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Sample records for chlorosis

  1. Delineating site-specific management zones for pH-induced iron chlorosis

    Science.gov (United States)

    Iron chlorosis can be a yield limiting factor in crop production especially on calcareous soils. Typical management for iron chlorosis includes the use of soil or foliar application of iron fertilizers, or the use of chlorosis tolerant cultivars. However, due to the interspersion of calcareous and n...

  2. Diodia vein chlorosis virus is a group-1 crinivirus.

    Science.gov (United States)

    Tzanetakis, Ioannis E; Wintermantel, William M; Poudel, Bindu; Zhou, Jing

    2011-11-01

    Members of the family Closteroviridae have emerged as a major problem in agricultural crops in the past two decades. Diodia vein chlorosis virus (DVCV) is an understudied whitefly-transmitted closterovirus. Given the presence of the primary host for the virus in major agricultural production areas in the United States, we characterized the virus at the molecular level, demonstrating that it belongs in the genus Crinivirus, developed detection protocols, evaluated its host range among hosts known to harbor viruses closely related to DVCV, and confirmed transmission by a second whitefly species, Trialeurodes vaporariorum.

  3. Morpho-physiological parameters affecting iron deficiency chlorosis response in soybean (Glycine max L.)

    Science.gov (United States)

    Iron deficiency chlorosis (IDC) leads to severe leaf chlorosis, low photosynthetic rates, and yield reductions of several million metric tons each year. In order to devise breeding and genetic transformation programs that aim at generating high-yielding and IDC-tolerant soybean lines, it is necessar...

  4. GRAPEVINE FE-CHLOROSIS ON PODUNAVLJE VINEGROWING AREA

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    Mato Drenjančević

    2012-06-01

    Full Text Available The characteristic of Podunavlje vinegrowing area in the far east of the Republic of Croatia is carbonate soil with loess as a parent substrate. Chlorosis is common on this soil and it is often caused by excess concentrations of calcium and magnesium and deficiency of iron and zinc. It can also be resulted by inactivation, if it is transformed so that a plant can not use it. The lack of iron in grape vine is resulted in leaf vein, first in younger leaves where the venation remains green, and then marginal necrosis and defoliation are developed. The results of the study include the data based on the field researches of Podunavlje vinegrowing subregion and exact research of fertilization field trial. Field research of Podunavlje vinegrowing subregion, vineyards of Srijem, Erdut and Baranya were conducted in July 2007. The field research consisted of locating plantations, measuring plantations chlorosis, determining their general condition and measuring total concentration of chloroplast pigments by an indirect method (chlorophyll meter on the chlorotic and nonchlorotic plants of a grapevine. The intensity of a relative chlorosis was calculated from data measured by a chlorophyll meter. Field research was located on the production area of a company Agro-Ilok ltd. in Ilok, locality Radoš, and carried out during the period 2008 and 2009. It included cultivar Welsh Riesling, grapevine stock Kober 5BB, the most important white cultivar and grapevine stock in the vinegrowing region Continental Croatia. The experiment was set up according to a split plot method at 5x3 levels. The main factor A consisted of different chemical treatments in a basic fertilization: : A1 = 0 control without fertilization; A2 = 150 kg P2O5 + 300 K2O kg ha-1 (KCl; A3 = 150 kg P2O5 + 300 K2O kg ha-1 (K2SO4; A4 = 150 kg P2O5 + 300 K2O kg ha-1 (KCl + 25 kg ha-1 Fe - FeSO4x7H2O; A5 = 150 kg P2O5 + 300 K2O kg ha-1 (K2SO4 + 25 kg ha-1 Fe - FeSO4x7H2O. Factor B had got three levels

  5. Genetic relationships of some Citrus genotypes based on the candidate iron chlorosis genes

    OpenAIRE

    KAÇAR, Yıldız AKA; Özhan ŞİMŞEK; DÖNMEZ, Dicle; BONCUK, Melda; YEŞİLOĞLU, Turgut; Ollitrault, Patrick

    2014-01-01

    Iron is one of the most important elements in plant mineral nutrition. Fe deficiency is a critical abiotic stress factor for Mediterranean citriculture; the development of marker-assisted selection for this trait would greatly enhance rootstock breeding. In this study, DNA sequencing and single-stranded conformation polymorphism (SSCP) analyses were performed to determine the allelic diversity of genes associated with tolerance to iron chlorosis in citrus. Two candidate iron chlorosis toleran...

  6. Accelerated senescence and enhanced disease resistance in hybrid chlorosis lines derived from interspecific crosses between tetraploid wheat and Aegilops tauschii.

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    Nakano, Hiroki; Mizuno, Nobuyuki; Tosa, Yukio; Yoshida, Kentaro; Park, Pyoyun; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions. PMID:25806790

  7. Accelerated senescence and enhanced disease resistance in hybrid chlorosis lines derived from interspecific crosses between tetraploid wheat and Aegilops tauschii.

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    Hiroki Nakano

    Full Text Available Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions.

  8. Ethylene-Induced Chlorosis in the Pathogenesis of Bipolaris sorokiniana Leaf Spot of Poa pratensis.

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    Hodges, C F; Coleman, L W

    1984-06-01

    Endogenous ethylene of Poa pratensis leaves infected by Bipolaris sorokiniana was evaluated as a factor in leaf chlorosis during pathogenesis. Detectable increases in endogenous ethylene of leaves of intact plants under normal ambient pressure occurred 12 hours after inoculation and was maximum at 48 hours; from 48 to 96 hours the ethylene progressively decreased. Necrotic lesions surrounded by chlorotic halos occurred on infected leaves between 24 and 48 hours. Midvein chlorosis interconnecting individual lesions and complete chlorosis of all tissues not directly affected by the lesions occurred between 72 and 96 hours, after maximum production of ethylene at 48 hours. The chlorophyll loss in infected leaves by 96 hours was 44% compared with controls.Subjecting inoculated leaves of intact plants to a controlled atmospheric-environmental system with an atmospheric pressure of 233 millibars and O(2) and CO(2) partial pressures adjusted to approximately that of normal ambient pressure during infection and disease development prevented most midvein chlorosis and complete chlorosis, but did not prevent necrotic lesion or chlorotic halo development. Under the hypobaric conditions, chlorophyll loss during disease development was reduced to 22% compared with controls at 96 hours. The observations suggest that ethylene may function late in pathogenesis of this host-pathogen interaction and is responsible for much of the chlorophyll loss after its maximum production at 48 hours.

  9. First report of taro vein chlorosis virus infecting taro [Colocasia esculenta (L.) Schott] in the United States of America

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    In March 2013, taro plants [Colocasia esculenta (L.) Schott cv. ‘iliuaua’] with leaves displaying veinal chlorosis and necrosis were observed at a germplasm collection on the island of Molokai. These symptoms were similar to those of taro vein chlorosis, an important disease of taro found in severa...

  10. RECOVERING FROM IRON DEFICIENCY CHLOROSIS IN NEAR ISOGENIC SOYBEANS: A MICROARRAY STUDY

    Science.gov (United States)

    Iron deficiency chlorosis (IDC) in soybeans has proven to be a perennial problem in the calcareous soils of the U.S. upper Midwest. A historically difficult trait to study in fields, the use of hydroponics in a controlled greenhouse environment has provided a mechanism to study genetic variation wh...

  11. Accelerated Senescence and Enhanced Disease Resistance in Hybrid Chlorosis Lines Derived from Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii

    OpenAIRE

    Hiroki Nakano; Nobuyuki Mizuno; Yukio Tosa; Kentaro Yoshida; Pyoyun Park; Shigeo Takumi

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlyin...

  12. Measuring leaf necrosis and chlorosis of bamboo induced by typhoon 0613 with RGB image analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; Haruhiko Yamamoto; Yasuomi Ibaraki

    2008-01-01

    Symptoms of leaf necrosis or chlorosis of bamboo induced by Typhoon 0613 (T0613) were analyzed using RGB image analysis in Yamaguchi city, Japan. Results showed a closely positive relationship between Green/Red (G/R) value for indoor taking images of bamboo individual leaves and chlorophyll meter value (SPAD) with regression coefficient of 0.961. The relation between G/R value of room taking images and Necrotic Area Percentage (NAP) for bamboo individual leaves showed an inverse logistic function relationship, with the correlated coefficient equaling to 0.958. Both leaf chlorosis and necrosis can be quantitatively estimated by RGB image analysis. Moreover, the variance of Green/Luminance (G/L) value for the same leaf was less than that of G/R for images taken in the conditions with large light difference, especially for green leaves. G/L value also exhibited a closer relationship with SPAD value of leaves with chlorosis than that of G/R values at the same condition. The relationship between G/L value for bamboo canopies and the Distance from Coastline (DC) was also closer than that of the G/R value for the images taken at field sites with big light difference.

  13. Complete genome sequence of bellflower vein chlorosis virus, a novel putative member of the genus Waikavirus.

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    Seo, Jang-Kyun; Kwak, Hae-Ryun; Lee, Ye-ji; Kim, Jaedeok; Kim, Mi-Kyeong; Kim, Chang-Seok; Choi, Hong-Soo

    2015-12-01

    The complete genome sequence of a new virus isolated from a bellflower (Campanula takesimana) plant was determined. The genome of this virus is composed of monopartite single-stranded RNA of 11,649 nucleotides in length. BLAST searches of protein databases showed that the encoded polyprotein has a maximum amino acid sequence identity of 42% (with 99% coverage) to the polyprotein of the isolate Orissa of rice tungro spherical virus (RTSV; genus Waikavirus). Phylogenetic analysis strongly supports that the identified virus is a member of a new species of the genus Waikavirus. The name bellflower vein chlorosis virus (BVCV) is proposed for this new virus.

  14. Reflectance spectroscopy: a tool for predicting soil properties related to the incidence of Fe chlorosis

    Energy Technology Data Exchange (ETDEWEB)

    Canasveras, J. C.; Barron, V.; Campillo, M. C. del; Viscarra Rossel, R. A.

    2012-07-01

    Chlorosis due to iron (Fe) deficiency (internervial yellowing) is the most important nutritional problem a susceptible plant can have in calcareous soils. Fe chlorosis is related with calcium carbonate equivalent (CCE), clay content and Fe extracted with oxalate (Fe{sub o}). Reflectance spectroscopy (RS) is a rapid, non-destructive, less expensive alternative tool that can be used to enhance or replace conventional methods of soil analysis. The aim of this work was to assess the usefulness of RS for the determination of some properties of Mediterranean soils including clay content, CCE, Feo, cation exchange capacity (CEC), organic matter (OM) and pH in water (pH{sub w}), with emphasis on those with a specially marked influence on the risk of Fe chlorosis. To this end, we used partial least-squares regression (PLS) to construct calibration models, leave-one-out cross-validation and an independent validation set. Our results testify to the usefulness of qualitative soil interpretations based on the variable importance for projection (VIP) as derived by PLS decomposition. The accuracy of predictions in each of the Vis-NIR, MIR and combined spectral regions differed considerably between properties. The R{sup 2}{sub a}dj and root mean square error (RMSE) for the external validation predictions were as follows: 0.83 and 37 mg kg{sup -}1 for clay content in the Vis-NIR-MIR range; 0.99 and 25 mg kg{sup -}1 for CCE, 0.80 and 0.1 mg kg{sup -}1 for Feo in the MIR range; 0.93 and 3 cmolc kg{sup -}1 for CEC in the Vis-NIR range; 0.87 and 2 mg kg{sup -}1 for OM in the Vis-NIR-MIR range, 0.61 and 0.2 for pH{sub w} in the MIR range. These results testify to the potential of RS in the Vis, NIR and MIR ranges for efficient soil analysis, the acquisition of soil information and the assessment of the risk of Fe chlorosis in soils. (Author) 36 refs.

  15. Induction of chlorosis, ROs generation and cell death by a toxin isolated from Pyricularia oryzae.

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    Tsurushima, Tetsu; Minami, Yukari; Miyagawa, Hisashi; Nakayashiki, Hitoshi; Tosa, Yukio; Mayama, Shigeyuki

    2010-01-01

    The ethyl acetate extract of the conidia germination fluid from an Avena isolate (Br58) of Pyricularia oryzae had chlorosis-inducing activity on oat leaf segments. The same activity was also present in the acetone extract of an oatmeal agar culture of Br58. Fungal cultures were used for a large-scale preparation. A series of acetone and ethyl acetate extraction monitored by chromatography was used to isolate an active fraction. The active principle was purified by HPLC. We show by NMR and LC/MS that the toxin was an oxidized C18 unsaturated fatty acid named Mag-toxin. Mag-toxin induced chlorosis on oat leaf segments incubated in the light but not in the dark. Reactive oxygen species (ROS) and cell death were induced by Mag-toxin in oat cells. The sub-cellular localization of ROS generation induced by the toxin treatment was correlated with the location of mitochondria. Interestingly, the induction of ROS generation and cell death by Mag-toxin was light-independent. PMID:21071840

  16. Identification of candidate genes involved in early iron deficiency chlorosis signaling in soybean (Glycine max) roots and leaves

    Science.gov (United States)

    Iron is an essential micronutrient for all living things, required in plants for photosynthesis, respiration and metabolism. A lack of bioavailable iron in soil leads to iron deficiency chlorosis (IDC), causing a reduction in photosynthesis and interveinal yellowing of leaves. Soybeans (Glycine ma...

  17. Mapping of iron and zinc quantitative trait loci in soybean for association to iron deficiency chlorosis resistance

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    Iron deficiency chlorosis (IDC) is a nutritional disease of soybean (Glycine max (L.) Merr.) which when left unchecked can result in a severe yield penalty or even death in the most extreme cases. In order to curb these effects, resistance to the disease is needed. Breeding for resistance has been ...

  18. The Vacuolar Manganese Transporter MTP8 Determines Tolerance to Iron Deficiency-Induced Chlorosis in Arabidopsis.

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    Eroglu, Seckin; Meier, Bastian; von Wirén, Nicolaus; Peiter, Edgar

    2016-02-01

    Iron (Fe) deficiency is a widespread nutritional disorder on calcareous soils. To identify genes involved in the Fe deficiency response, Arabidopsis (Arabidopsis thaliana) transfer DNA insertion lines were screened on a high-pH medium with low Fe availability. This approach identified METAL TOLERANCE PROTEIN8 (MTP8), a member of the Cation Diffusion Facilitator family, as a critical determinant for the tolerance to Fe deficiency-induced chlorosis, also on soil substrate. Subcellular localization to the tonoplast, complementation of a manganese (Mn)-sensitive Saccharomyces cerevisiae yeast strain, and Mn sensitivity of mtp8 knockout mutants characterized the protein as a vacuolar Mn transporter suitable to prevent plant cells from Mn toxicity. MTP8 expression was strongly induced on low-Fe as well as high-Mn medium, which were both strictly dependent on the transcription factor FIT, indicating that high-Mn stress induces Fe deficiency. mtp8 mutants were only hypersensitive to Fe deficiency when Mn was present in the medium, which further suggested an Mn-specific role of MTP8 during Fe limitation. Under those conditions, mtp8 mutants not only translocated more Mn to the shoot than did wild-type plants but suffered in particular from critically low Fe concentrations and, hence, Fe chlorosis, although the transcriptional Fe deficiency response was up-regulated more strongly in mtp8. The diminished uptake of Fe from Mn-containing low-Fe medium by mtp8 mutants was caused by an impaired ability to boost the ferric chelate reductase activity, which is an essential process in Fe acquisition. These findings provide a mechanistic explanation for the long-known interference of Mn in Fe nutrition and define the molecular processes by which plants alleviate this antagonism. PMID:26668333

  19. Effectiveness of mixtures of vivianite and organic materials in preventing iron chlorosis in strawberry

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, A. de; Carmona, E.; Quintero, J. M.; Delgado, A.

    2013-05-01

    Application of Fe salts with different organic matter sources has been demonstrated to be effective in preventing Fe deficiency chlorosis. The main objective of this work was to study the effectiveness of different Fe sources based on mixtures of humic substances or compost with vivianite in preventing this nutritional disorder in strawberry (Fragaria x ananassa cv Camarosa). To this end, a randomised block experiment involving four replications (3 plants per replication) and one factor (Fe source) was performed in a greenhouse using a calcareous growing medium. Iron sources studied were: (i) control without Fe, (ii) control with an effective Fe source in calcareous media (EDDHA-Fe, 0.1 g kg{sup -}1), (iii) vivianite (1 g kg{sup -}1 medium, which is the recommended rate), (iv) vivianite (1 g kg{sup -}1) + humic substances (HS 0.06 g kg{sup -}1), (v) vivianite (0.5 g kg{sup -}1) + HS (0.06 g kg{sup -}1) and (vi) a mixture of composted cork residue and vivianite at a 6:1 mass ratio (CORVIV) applied at a dose of 6 g kg-1 medium. All Fe sources were effective in increasing SPAD readings when compared with control without Fe. Treatments based on vivianite provided non-significantly different SPAD readings from that obtained with EDDHA-Fe. However, only CORVIV showed non-significantly different dry matter (DM) production, leaf area index, and total Fe content in the aerial part than EDDHA-Fe. Humic substances and vivianite at 1 g kg{sup -}1 increased DM yield in plants when compared with vivianite without HS, results with this last treatment being similar to those obtained with vivianite at 0.5 g kg–1 with HS. It can be concluded that studied sources of organic matter increased the efficiency of vivianite in preventing Fe chlorosis in strawberry, especially vivianite enriched cork compost which was as effective as EDDHA-Fe. (Author) 50 refs.

  20. Comparative analysis for quantification of Citrus Variegated Chlorosis in the field

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    Fabrício Packer Gonçalves

    2011-10-01

    Full Text Available Citrus Variegated Chlorosis (CVC caused by Xylella fastidiosa is one of the most important diseases for Brazilian citriculture. The CVC is a vascular disease with a long incubation period and symptoms similar to other disorders, and this factors difficult the CVC quantification in the field. Two methods of CVC assessment were compared in this study. The first method was based on a descriptive rating scale with four ratings, commonly used for the disease quantification. The second one was based on the incidence of symptomatic branches. The quantification of CVC through these two methods was carried out in a 10-year-old 'Natal' sweet orange orchard. The descriptive scale considered the symptoms of the entire plant. The disease incidence was evaluated in 36 branches in each plant. The assessments were conducted by three raters in 144 plants in July 2006 and July 2007 as well as in March and November 2008. The descriptive scale did not allow an accurate assessment and resulted in a moderate strength of agreement among the raters. On the other hand, the incidence quantification of CVC through the symptomatic branches showed high repeatability among the raters. We suggest the use of incidence of symptomatic branches as variable for CVC quantification.

  1. Fine mapping of Hch1, the causal D-genome gene for hybrid chlorosis in interspecific crosses between tetraploid wheat and Aegilops tauschii.

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    Hirao, Kana; Nishijima, Ryo; Sakaguchi, Kohei; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, one of the reproductive barriers between tetraploid wheat and its D-genome progenitor, Aegilops tauschii, inhibits normal growth of synthetic wheat hexaploids. Hybrid chlorosis appears to be due to an epistatic interaction of two loci from the AB and D wheat genomes. Our previous study assigned the causal D-genome gene for hybrid chlorosis, Hch1, to the short arm of chromosome 7D. Here, we constructed a fine map of 7DS near Hch1 using 280 F2 individuals from a cross of two wheat synthetic lines, one showing normal growth and the other showing hybrid chlorosis. The hybrid chlorosis phenotype was controlled by a single dominant allele of the Hch1 locus in the synthetic hexaploids. Hch1 was closely linked to four new markers within 0.2 cM, and may be localized near or within the two Ae. tauschii scaffolds containing the linked markers on 7DS. Comparative analysis of the Hch1 chromosomal region for Ae. tauschii, barley and Brachypodium showed that a local inversion occurred in the region proximal to Hch1 during the divergence between barley and Ae. tauschii, and that the Hch1 region on wheat 7DS is syntenic to Brachypodium chromosome 1. These observations provide useful information for further studies toward map-based cloning of Hch1. PMID:26687862

  2. Transcriptome Analysis of Capsicum Chlorosis Virus-Induced Hypersensitive Resistance Response in Bell Capsicum

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    Widana Gamage, Shirani M. K.; McGrath, Desmond J.; Persley, Denis M.

    2016-01-01

    Background Capsicum chlorosis virus (CaCV) is an emerging pathogen of capsicum, tomato and peanut crops in Australia and South-East Asia. Commercial capsicum cultivars with CaCV resistance are not yet available, but CaCV resistance identified in Capsicum chinense is being introgressed into commercial Bell capsicum. However, our knowledge of the molecular mechanisms leading to the resistance response to CaCV infection is limited. Therefore, transcriptome and expression profiling data provide an important resource to better understand CaCV resistance mechanisms. Methodology/Principal Findings We assembled capsicum transcriptomes and analysed gene expression using Illumina HiSeq platform combined with a tag-based digital gene expression system. Total RNA extracted from CaCV/mock inoculated CaCV resistant (R) and susceptible (S) capsicum at the time point when R line showed a strong hypersensitive response to CaCV infection was used in transcriptome assembly. Gene expression profiles of R and S capsicum in CaCV- and buffer-inoculated conditions were compared. None of the genes were differentially expressed (DE) between R and S cultivars when mock-inoculated, while 2484 genes were DE when inoculated with CaCV. Functional classification revealed that the most highly up-regulated DE genes in R capsicum included pathogenesis-related genes, cell death-associated genes, genes associated with hormone-mediated signalling pathways and genes encoding enzymes involved in synthesis of defense-related secondary metabolites. We selected 15 genes to confirm DE expression levels by real-time quantitative PCR. Conclusion/Significance DE transcript profiling data provided comprehensive gene expression information to gain an understanding of the underlying CaCV resistance mechanisms. Further, we identified candidate CaCV resistance genes in the CaCV-resistant C. annuum x C. chinense breeding line. This knowledge will be useful in future for fine mapping of the CaCV resistance locus and

  3. Iron deficiency chlorosis in plants as related to Fe sources in soil

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    Díaz, I.; Delgado, A.; de Santiago, A.; del Campillo, M. C.; Torrent, J.

    2012-04-01

    Iron deficiency chlorosis (IDC) is a relevant agricultural problem in many areas of the World where calcareous soils are dominant. Although this problem has been traditionally ascribed to the pH-buffering effect of soil carbonates, the content and type of Fe oxides in soil contribute to explain Fe uptake by plants and the incidence of this problem. During the last two decades, it has been demonstrated Fe extraction with oxalate, related to the content of poorly crystalline Fe oxides, was well-correlated with the chlorophyll content of plants and thus with the incidence of IDC. This reveals the contribution of poorly crystalline Fe oxides in soil to Fe availability to plants in calcareous soils, previously shown in microcosm experiments using ferrihydrite as Fe source in the growing media. In order to supply additional information about the contribution of Fe sources in soil to explain the incidence of IDC and to perform accurate methods to predict it, a set of experiments involving different methods to extract soil Fe and plant cultivation in pots to correlate amounts of extracted Fe with the chlorophyll content of plants (measured using the SPAD chlorophyll meter) were performed. The first experiment involved 21 soils and white lupin cultivation, sequential Fe extraction in soil to study Fe forms, and single extractions (DTPA, rapid oxalate and non-buffered hydroxylamine). After that, a set of experiments in pot involving growing of grapevine rootstocks, chickpea, and sunflower were performed, although in this case only single extractions in soil were done. The Fe fraction more closely related to chlorophyll content in plants (r = 0.5, p citrate + ascorbate (CA) extraction, which was the fraction that releases most of the Fe related to poorly crystalline Fe oxides, thus revealing the key role of these compounds in Fe supply to plants. Fe extracted with CA was more correlated with chlorophyll content in plants that oxalate extractable Fe, probably due to a more

  4. "Candidatus Phlomobacter fragariae" Is the Prevalent Agent of Marginal Chlorosis of Strawberry in French Production Fields and Is Transmitted by the Planthopper Cixius wagneri (China).

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    Danet, Jean-Luc; Foissac, Xavier; Zreik, Leyla; Salar, Pascal; Verdin, Eric; Nourrisseau, Jean-Georges; Garnier, Monique

    2003-06-01

    ABSTRACT Marginal chlorosis has affected strawberry production in France for about 15 years. A phloem-restricted uncultured bacterium, "Candidatus Phlomobacter fragariae," is associated with the disease. A large-scale survey for marginal chlorosis in French strawberry production fields and nurseries by polymerase chain reaction amplification of "Ca. P. fragariae" 16S rDNA revealed that symptoms of marginal chlorosis were not always induced by "Ca. P. fragariae" and that the stolbur phytoplasma could induce identical symptoms. "Ca. P. fragariae" was found to be predominant in strawberry production fields, whereas the stolbur phytoplasma was predominantly detected in nurseries. Two transmission periods of the disease, one in spring and the other from late summer to early fall, were evident. Cixius wagneri planthoppers captured on infected strawberry plants were demonstrated to be efficient vectors of "Ca. P. fragariae." The involvement in natural disease spread of the whitefly Trialeurodes vaporariorum, previously shown to acquire and multiply "Ca. P. fragariae" under greenhouse conditions, remains uncertain.

  5. Overexpression of SlRBZ Results in Chlorosis and Dwarfism through Impairing Chlorophyll, Carotenoid, and Gibberellin Biosynthesis in Tomato.

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    Fan, Mingqin; Gao, Shenghua; Ren, Junling; Yang, Qihong; Li, Hanxia; Yang, Changxian; Ye, Zhibiao

    2016-01-01

    ZFPs play important roles in many biological processes, including plant development, stress response, and phytohormone response. RanBP2-type zinc finger transcription factors have been characterized in animals and humans. However, their functions remain largely unknown in plants. In this study, we identified a RanBP2-type zinc finger protein gene (SlRBZ) in tomato. SlRBZ was constitutively expressed in roots, stems, leaves, flowers, and fruits. The SlRBZ-GFP fused protein was localized in the nucleus. Overexpression of SlRBZ resulted in chlorosis and dwarf phenotypes in tomato. Determination of physiological index showed that chlorophyll, carotenoid, and GAs contents were evidently decreased in transgenic plants. Furthermore, the qRT-PCR and RNA-Seq analyses demonstrated that the transcription of the genes involved in these biosynthesis pathways obviously decreased in SlRBZ-OE plants. In addition, ultrastructural observation by transmission electron microscopy indicated that plastids could not develop into mature chloroplasts with normal chloroplast membrane and thylakoid membrane system in SlRBZ-OE plants. The results suggest that overexpression of SlRBZ may impair the biosynthesis of chlorophyll, carotenoid, and gibberellin through blocking chloroplast development, resulting in chlorosis and dwarfism in tomato. PMID:27446137

  6. Genome-wide association studies identifies seven major regions responsible for iron deficiency chlorosis in soybean (Glycine max.

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    Sujan Mamidi

    Full Text Available Iron deficiency chlorosis (IDC is a yield limiting problem in soybean (Glycine max (L. Merr production regions with calcareous soils. Genome-wide association study (GWAS was performed using a high density SNP map to discover significant markers, QTL and candidate genes associated with IDC trait variation. A stepwise regression model included eight markers after considering LD between markers, and identified seven major effect QTL on seven chromosomes. Twelve candidate genes known to be associated with iron metabolism mapped near these QTL supporting the polygenic nature of IDC. A non-synonymous substitution with the highest significance in a major QTL region suggests soybean orthologs of FRE1 on Gm03 is a major gene responsible for trait variation. NAS3, a gene that encodes the enzyme nicotianamine synthase which synthesizes the iron chelator nicotianamine also maps to the same QTL region. Disease resistant genes also map to the major QTL, supporting the hypothesis that pathogens compete with the plant for Fe and increase iron deficiency. The markers and the allelic combinations identified here can be further used for marker assisted selection.

  7. Citrus Functional Genomics and Molecular Modeling in Relation to Citrus sinensis (Sweet Orange) Infection with Xylella fastidiosa (Citrus Variegated Chlorosis).

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    Dwivedi, Upendra N; Tiwari, Sameeksha; Prasanna, Pragya; Awasthi, Manika; Singh, Swati; Pandey, Veda P

    2016-08-01

    Citrus are among the economically most important fruit tree crops in the world. Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa infection, is a serious disease limiting citrus production at a global scale. With availability of citrus genomic resources, it is now possible to compare citrus expressed sequence tag (EST) data sets and identify single-nucleotide polymorphisms (SNPs) within and among different citrus cultivars that can be exploited for citrus resistance to infections, citrus breeding, among others. We report here, for the first time, SNPs in the EST data sets of X. fastidiosa-infected Citrus sinensis (sweet orange) and their functional annotation that revealed the involvement of eight C. sinensis candidate genes in CVC pathogenesis. Among these genes were xyloglucan endotransglycosylase, myo-inositol-1-phosphate synthase, and peroxidase were found to be involved in plant cell wall metabolism. These have been further investigated by molecular modeling for their role in CVC infection and defense. Molecular docking analyses of the wild and the mutant (SNP containing) types of the selected three enzymes with their respective substrates revealed a significant decrease in the binding affinity of substrates for the mutant enzymes, thus suggesting a decrease in the catalytic efficiency of these enzymes during infection, thereby facilitating a favorable condition for infection by the pathogen. These findings offer novel agrigenomics insights in developing future molecular targets and strategies for citrus fruit cultivation in ways that are resistant to X. fastidiosa infection, and by extension, with greater harvesting efficiency and economic value. PMID:27447755

  8. Danos causados pelo Zucchini lethal chlorosis virus (ZLCV sobre a produção de frutos comerciais de abobrinha de moita 'Caserta' Yield loss caused by Zucchini lethal chlorosis virus (ZLCV on zucchini squash 'Caserta'

    Directory of Open Access Journals (Sweden)

    José Segundo Giampan

    2009-09-01

    Full Text Available O ZLCV é um tospovírus encontrado com freqüência causando severos danos em cucurbitáceas. Nesse trabalho avaliaram-se os danos causados pelo ZLCV em abobrinha de moita 'Caserta', em campo na ESALQ/USP, Piracicaba-SP, onde esse vírus é freqüente. Plantas obtidas pela semeadura direta foram monitoradas periodicamente quanto à infecção pelo ZLCV por meio dos sintomas e por PTA-ELISA. Monitorou-se ainda a contaminação com Papaya ringspot virus - type W e Zucchini yellow mosaic virus, desconsiderando a produção dessas plantas. As plantas foram agrupadas em função da época de aparecimento dos sintomas do ZLCV, avaliando a produção de frutos comerciais (FC e não comerciais (FNC de cada grupo e comparando com a de plantas que permaneceram sem sintomas até o final do experimento. As plantas que apresentaram sintomas até os 23 dias após a emergência (DAE não produziram qualquer tipo de frutos. FC foram colhidos de plantas que apresentaram sintomas a partir dos 42 DAE. Mesmo assim, houve redução de 78,5 % na produção de FC. Plantas que mostraram sintomas por ocasião da última colheita (55 DAE apresentaram redução na produção de FC de 9,6 %. A infecção com o ZLCV até o início da frutificação inviabiliza a produção de FC de abobrinha de moita 'Caserta'.Zucchini lethal chlorosis virus (ZLCV is a tospovirus frequently associated with severe yield loss on cucurbit crops. The purpose of this work was to evaluate the damage caused by this virus on zucchini squash (Cucurbita pepo cv. Caserta under field condition. The experiment was carried out at the Campus of the College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil, were ZLCV is prevalent. After germination, zucchini squash plants were periodically monitored for the presence of characteristic symptoms induced by ZLCV and PTA-ELISA for virus indexing. Infection by Papaya ringspot virus - type W and Zucchini yellow mosaic virus were also monitored by

  9. Etiology of three recent diseases of citrus in São Paulo State: sudden death, variegated chlorosis and huanglongbing.

    Science.gov (United States)

    Bové, Joseph Marie; Ayres, Antonio Juliano

    2007-01-01

    , citrus variegated chlorosis (CVC), was observed in 1987 in the Triangulo Mineiro of Minas Gerais State and the northern and north-eastern parts of SSP. By 2000, the disease affected already 34% of the 200 million sweet orange trees in SSP. By 2005, the percentage had increased to 43%, and CVC was present in all citrus growing regions of Brazil. Electron microscopy showed that xylem-limited bacteria were present in all symptomatic sweet orange leaves and fruit tissues tested, but not in similar materials from healthy, symptomless trees. Bacteria were consistently cultured from twigs of CVC-affected sweet orange trees but not from twigs of healthy trees. Serological analyses showed the CVC bacterium to be a strain of Xylella fastidiosa. The disease could be reproduced and Koch's postulates fulfilled, by mechanically inoculating a pure culture of X. fastidiosa isolate 8.1.b into sweet orange seedlings. The genome of a CVC strain of X. fastidiosa was sequenced in SSP in the frame of a project supported by FAPESP and Fundecitrus. X. fastidiosa is the first plant pathogenic bacterium, the genome of which has been sequenced. Until recently, America was free of huanglongbing (HLB), but in March 2004 and August 2005, symptoms of the disease were recognized, respectively in the State of São Paulo (SSP) and in Florida, USA. HLB was known in China since 1870 and in South Africa since 1928. Because of its destructiveness and its rapid spread by efficient psyllid insect-vectors, HLB is probably the most serious citrus disease. HLB is caused by a phloem sieve tube-restricted Gram negative bacterium, not yet available in culture. In the 1990s, the bacterium was characterized by molecular techniques as a member of the alpha proteobacteria designated Candidatus Liberibacter africanus for the disease in Africa, and Candidatus Liberibacter asiaticus for HLB in Asia. In SSP, Ca. L. asiaticus is also present, but most of the trees are infected with a new species, Candidatus Liberibacter

  10. 猕猴桃黄化病营养诊断与土壤养分相关性的研究%Nutrients diagnosis of kiwi fruit chlorosis and study on relativity of soil nutrients

    Institute of Scientific and Technical Information of China (English)

    Tran Le Linh; 马海洋; 同延安; 路永莉; 来源; 刘芬; 陈毓君; 林文

    2012-01-01

    西北地区以石灰性土壤为主,土壤微量元素有效性较低,种植猕猴桃易出现黄化现象.采集正常和黄化猕猴桃叶片及其树冠下土壤样品进行营养诊断分析.结果表明,除Ca外,黄化叶片中N、P、K、Cu、Fe含量均较低,与正常叶片含量相比差异达极显著,其中Cu和Fe分别为正常叶片的66.85%与65.61%.铁是叶绿素合成的必需元素,表明黄化原因与缺铁有关.正常和黄化树体下土层各养分测定值差异不显著;说明植株叶片养分缺乏是植株根系吸收养分受阻,与土壤养分丰缺无关.需要通过改善土壤的其他条件(如pH,水分,通气状况等)或叶面喷肥来促进树体吸收.%The availabilities of trace elements in calcareous soil which is the main soil type in northwest of China are low. Iron-deficiency chlorosis is a common phenomenon to kiwi in calcareous soil. Leaves and soil samples of the normal and chlorosis kiwifruit trees were studied with nutrient diagnosis method. Except for calcium, the concentrations of nitrogen, phosphorus, potassium, copper and iron in leaves of chlorosis trees were significant lower than that of normal trees, especially copper and iron, contents of which in leaves of chlorosis trees were 66. 85% and 65. 61 % of normal trees, respectively. Iron was an essential element for chlorophyll synthesis, which showed chlorosis was related to iron deficiency. There were no significant differences with soil nutrients content between normal trees and chlorosis trees, which indicated the deficiencies of nutrients in leaves attribute to the obstruction of nutrients to absorb by root, and there was no significant relationship with the abundance and deficiency of soil nutrients. Absorption ability of trees could be improved through foliage fertilization, regulating soil pH value, moisture, aeration and so on.

  11. Development and systematic validation of qPCR assays for rapid and reliable differentiation of Xylella fastidiosa strains causing citrus variegated chlorosis.

    Science.gov (United States)

    Li, Wenbin; Teixeira, Diva C; Hartung, John S; Huang, Qi; Duan, Yongping; Zhou, Lijuan; Chen, Jianchi; Lin, Hong; Lopes, Silvio; Ayres, A Juliano; Levy, Laurene

    2013-01-01

    The xylem-limited, Gram-negative, fastidious plant bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC), a destructive disease affecting approximately half of the citrus plantations in the State of São Paulo, Brazil. The disease was recently found in Central America and is threatening the multi-billion U.S. citrus industry. Many strains of X. fastidiosa are pathogens or endophytes in various plants growing in the U.S., and some strains cross infect several host plants. In this study, a TaqMan-based assay targeting the 16S rDNA signature region was developed for the identification of X. fastidiosa at the species level. Another TaqMan-based assay was developed for the specific identification of the CVC strains. Both new assays have been systematically validated in comparison with the primer/probe sets from four previously published assays on one platform and under similar PCR conditions, and shown to be superior. The species specific assay detected all X. fastidiosa strains and did not amplify any other citrus pathogen or endophyte tested. The CVC-specific assay detected all CVC strains but did not amplify any non-CVC X. fastidiosa nor any other citrus pathogen or endophyte evaluated. Both sets were multiplexed with a reliable internal control assay targeting host plant DNA, and their diagnostic specificity and sensitivity remained unchanged. This internal control provides quality assurance for DNA extraction, performance of PCR reagents, platforms and operators. The limit of detection for both assays was equivalent to 2 to 10 cells of X. fastidiosa per reaction for field citrus samples. Petioles and midribs of symptomatic leaves of sweet orange harbored the highest populations of X. fastidiosa, providing the best materials for detection of the pathogen. These new species specific assay will be invaluable for molecular identification of X. fastidiosa at the species level, and the CVC specific assay will be very powerful for the

  12. Search of Xylella fastidiosa in plants with symptoms of chlorosis and leaf scorch present in ornamental areas in the university district and nearness

    International Nuclear Information System (INIS)

    The presence of Xylella fastidiosa is detected in plants considered as hosts of urban ornament with characteristic symptoms, present in gardens in the area of the university district and around in the area. Urban ornamental plants are identified with suggestive symptomatology of infection by X. fastidiosa in gardens of urban areas. Plants are classified according to the presence or absence of symptoms. In the study were gathered 97 samples, belonging to 29 vegetable species with symptoms of chlorosis on leaves, leaf scorch, delay in the development and loss of foliage. The identified plants are screened by techniques of ELISA, and immunofluorescence for the detection of X. fastidiosa. Xylella fastidiosa is isolated from urban ornamental plants. The isolates of Xylella obtained, are characterized phenotypic and molecularly. The performance of two standardized immunological techniques are compared for the serological detection of Xylella fastidiosa. The presence of X. fastidiosa is detected, using the DAS-ELISA technique on 48 of the 97 processed samples, corresponding to 46,1% of the samples. Parallely, the samples processed using the IFA technique, have detected the presence of X. fastidiosa in the same proportions

  13. Enhanced Reliability and Accuracy for Field Deployable Bioforensic Detection and Discrimination of Xylella fastidiosa subsp. pauca, Causal Agent of Citrus Variegated Chlorosis Using Razor Ex Technology and TaqMan Quantitative PCR

    OpenAIRE

    Ping Ouyang; Mohammad Arif; Jacqueline Fletcher; Ulrich Melcher; Francisco Manuel Ochoa Corona

    2013-01-01

    A reliable, accurate and rapid multigene-based assay combining real time quantitative PCR (qPCR) and a Razor Ex BioDetection System (Razor Ex) was validated for detection of Xylella fastidiosa subsp. pauca (Xfp, a xylem-limited bacterium that causes citrus variegated chlorosis [CVC]). CVC, which is exotic to the United States, has spread through South and Central America and could significantly impact U.S. citrus if it arrives. A method for early, accurate and sensitive detection of Xfp in pl...

  14. Avaliação de tangerinas, tangores e tangelos em relação à clorose variegada dos citros Evaluation of mandarines, tangors and tangelos in relation to the citrus variegated chlorosis (CVC

    Directory of Open Access Journals (Sweden)

    Simone Rodrigues da Silva

    2004-04-01

    Full Text Available A Clorose Variegada dos Citros (CVC, causada pela bactéria Xylella fastidiosa, é uma séria ameaça à citricultura brasileira, constituindo-se, atualmente, numa das principais doenças dos citros no Brasil. O objetivo desse trabalho foi avaliar cultivares de citros introduzidas quanto à suscetibilidade ou resistência à CVC, em condições de campo. O trabalho foi conduzido em Bebedouro-SP. Os materiais genéticos estudados foram cultivares de tangerinas e híbridos (tangores e tangelos introduzidas de bancos de germoplasma da Itália, Portugal, Espanha e Córsega. O trabalho foi constituído por 56 parcelas, com três plantas das quais uma foi inoculada, empregando-se o método de encostia, utilizando-se de mudas previamente infectadas como fontes da bactéria. Foram avaliados os sintomas da doença mediante observação visual através de notas e teste de PCR, específico para Xylella fastidiosa. Os materiais genéticos que se apresentaram positivos ao PCR, mas não apresentaram sintomas, e os que foram negativos ao PCR, possuem um potencial de utilização em programas de melhoramento genético visando à resistência e/ou à tolerância à doença.The Citrus Variegated Chlorosis (CVC, caused by the bacteria Xylella fastidiosa, is a serious threat to the Brazilian citriculture, being, actually, one of the mains diseases to the citrus in Brazil. The objective of this work was evaluate citrus cultivars, introduced according to the susceptibility or resistance to CVC, in field conditions. The research was carried in Bebedouro city - São Paulo state - Brazil. The genotypes studied were cultivars of mandarines and hybrids (tangors and tangelos, introduced from the germplasm collections of Italy, Portugal, Spain and Corsica. The work was composed by 56 portions, with 3 plants, being one of them inoculated, using the approach graft method, with infected plants. Were evaluated the symptoms of the disease by visual observation and PCR test

  15. 番茄褪绿病毒 CP 基因克隆、序列分析及原核表达%Cloning,Sequence Analysis and Prokaryotic Expression of Coat Protein Gene of Tomato chlorosis virus

    Institute of Scientific and Technical Information of China (English)

    韩磊; 迟胜起; 张剑峰

    2016-01-01

    In order to prepare the special antiserum of Tomato chlorosis virus(ToCV),the total RNA of tomato leaves infected with ToCV were extracted.According to the coat protein gene of ToCV,specific primers were de-signed to amplify the coding region of coat protein by RT-PCR,the prokaryotic expression vector pET32a-ToCVCP was constructed and the recombinant protein was expressed in E.coli Rosetta (DE3).The results showed that the ToCV CP gene(NCBI:KT809400)owned 774 bp nucleotides,encoding 257 amino acids.The similarity of nucleo-tide and predicted protein were 97.2% -99.6% and 97.3% -100.0%,respectively,compared with the CP gene of other ToCV isolates registered in GenBank.The nucleotide sequence of conserved sites accounted for 91 .3% of all loci,the amino acid sequence conserved sites accounted for 88.3% of all loci,indicated that the geographical or-igin of different ToCV CP gene had a relative higher conservative property.The ToCV CP gene was subcloned into the expression vector pET-32a(+)and the fusion protein was expressed in vitro.SDS-PAGE analysis showed that a specific recombinant protein of approximately 33 kDa was produced in the Rosetta (DE3)with the prokaryotic ex-pression vector pET32a-ToCVCP in 37 ℃with 1 .0 mmol /L IPTG for 6 hours.%为制备番茄褪绿病毒(Tomato chlorosis virus,ToCV)抗血清,以番茄病叶为试验材料,提取总 RNA,根据ToCV CP 基因设计特异性引物,利用 RT-PCR 方法克隆目的基因,构建原核表达载体 pET32a-ToCVCP,在大肠杆菌Rosetta (DE3)菌株中表达 CP 蛋白。结果表明:ToCV CP 基因(GenBank 登录号:KT809400)全长774 bp,编码257个氨基酸,与 GenBank 中其他地区分离物核苷酸序列同源性为97.2%~99.6%,推导的氨基酸序列同源性为97.3%~100.0%。核苷酸序列保守位点占全部位点的91.3%,氨基酸序列保守位点占全部位点的88.3%,表明不同地理来源的番茄褪绿病毒的 CP

  16. 侵染番茄的番茄褪绿病毒山东泰安分离物的分子鉴定和序列分析%Molecular detection and sequence analysis of Tomato chlorosis virus infecting tomato in Tai’an,Shandong Province

    Institute of Scientific and Technical Information of China (English)

    赵黎明; 李刚; 刘永杰; 刘永光; 孙国珍; 竺晓平

    2014-01-01

    2012年秋季,在山东泰安番茄主要种植区中采集到叶片褪绿,叶脉颜色变深的疑似番茄褪绿病毒病和番茄侵染性褪绿病毒病的番茄样品。利用番茄褪绿病毒(Tomato chlorosis virus ,ToCV)的特异引物 ToCV1/ToCV2和番茄侵染性褪绿病毒(Tomato infectious chlorosis virus ,TICV)的特异引物 TICV1/TICV2分别对样品进行扩增,最后仅得到利用引物 ToCV1/ToCV2扩增的101 bp 的核苷酸序列,对该核苷酸序列克隆并测序。序列比对表明,山东泰安地区分离物与已登录的番茄褪绿病毒(ToCV)分离物相似性都在99%以上。随后,对山东泰安种植区ToCV 番茄分离物进行外壳蛋白(CP)及热激蛋白(HSP70)序列的扩增、克隆和测序(GenBank 登录号 KC812620/KC812625),经 NCBI BLAST 比对发现,目的序列与番茄褪绿病毒日本番茄分离物 ToCV-Japan/Tochigi(GenBank登录号 AB513442/AB513443)相似性最高为99%,同属于毛型病毒属的番茄褪绿病毒,这是首次明确山东地区番茄受到番茄褪绿病毒的侵染。%In the autumn of 2012,tomato plants showing symptoms of interveinal chlorosis,leaf curling and nec-rotic fleck on lower leaves,similar to symptoms induced by Tomato chlorosis virus (ToCV)and Tomato infectious chlorosis virus (TICV)(two members of the genus Crinivirus in the family Closteroviridae)were collected in Tai’an, Shandong Province.Reverse transcription polymerase chain reaction (RT-PCR)was performed to test the presence of ToCV and TICVwith the specific primers ToCV1/ToCV2 and TICV1/TICV2 for ToCV and TICV,respectively.Only with ToCV primers,a 101-bp specific fragment was amplified from the symptomatic samples,and no amplification with TICV primers from any samples.Sequence analysis of the amplified fragment shared 99% nucleotide sequence identity with that of ToCV isolates registered in the NCBI.The presence of ToCV was confirmed by using the specific primer

  17. Fluxo de seiva e fotossíntese em laranjeira 'Natal' com clorose variegada dos citros Sap flow and photosynthesis of 'Natal' sweet orange plants with citrus variegated chlorosis

    Directory of Open Access Journals (Sweden)

    Eduardo Caruso Machado

    2006-06-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos da clorose variegada dos citros (CVC, no fluxo de seiva, trocas gasosas e atividade fotoquímica em laranjeira 'Natal', com e sem CVC, em condição de campo. O curso diário do fluxo de seiva, potencial da água na folha, assimilação de CO2, transpiração, condutância estomática e eficiência quântica máxima e efetiva do fotossistema II foram avaliados. O delineamento experimental foi em blocos ao acaso com cinco repetições. O fluxo de seiva foi 1,9 vez superior nas plantas sadias em relação às doentes. Em plantas doentes ocorreu queda de 43, 28 e 33% na assimilação de CO2, condutância estomática e transpiração, respectivamente. As plantas com CVC apresentaram fotoinibição dinâmica. Uma vez que a eficiência quântica efetiva apresentou um padrão de resposta semelhante, durante o dia, em ambos os tratamentos, o efeito protetor da fotorrespiração no aparato fotoquímico em plantas com CVC é discutido. As quedas de assimilação de CO2, transpiração e de fluxo de seiva, nas plantas com CVC, foram decorrentes do menor valor da condutância estomática, possivelmente causado pela colonização dos vasos do xilema pela Xylella fastidiosa.The objective of this work was to evaluate the effects of citrus variegated chlorosis (CVC on sap flow, gas exchanges and photochemical activity in 'Natal' sweet orange plants with and without CVC under field condition. Diurnal courses of sap flow, leaf water potential, CO2 assimilation rate and transpiration, stomatal conductance, potential and effective quantum efficiency of photosystem II were evaluated. The experiment was arranged in a random block design with five repetitions. Healthy plants showed sap flow values around 1.9 times higher than injured ones. Injured plants exhibited reductions of 43, 28 and 33% in CO2 assimilation rate, stomatal conductance and leaf transpiration, respectively. CVC-affected plants showed dynamic

  18. 不同铁制剂对石灰性土壤条件下猕猴桃缺铁黄化的矫治效果%Effects of different iron preparations on iron chlorosis of kiwifruit trees in lime soil conditions

    Institute of Scientific and Technical Information of China (English)

    王光州; 韩慧韬; 车金鑫; 张向东; 翟丙年

    2011-01-01

    This study was conducted to find the reasons for the kiwifruit chlorosis in Yangling Wei River flood land and to select better iron preparations for remedying it. Soil and plant diagnosis and spraying diagnosis were used onto the kiwifruit vines in some orchards within Yangling area. The remedy effects of different iron preparations were compared by determining the content of Chlorophyll and available iron of kiwifruit leaves and fruit quality. The results showed that the reason for kiwifruit chlorosis was not only low iron content in soil, but also owing to differences of absorption capacity of plants, which made plants absorb too much P, K, Zn, Mn and other elements into the plants, causing nutrient imbalances that resulted in the antagonism on the absorption of iron. The effects of the various iron preparations were significantly different. The citrate-Fe and the compound amino acid-Fe treatment were much better than others. These iron preparations significantly increased the content of Chlorophyll and available irons in the kiwifruit leaves and the content of Vc, soluble solids and irons, which effectively improved the quality of fruits. Among these iron preparations used in this study, the citrate-Fe and the compound amino acid-Fe are better iron preparations for correcting kiwifruit chlorosis.%为明确陕西杨凌渭河滩地猕猴桃出现黄化现象的原因,通过对喷施铁制剂矫正效果的比较,筛选出理想的铁制剂用于果树缺铁黄化病防治.以陕西杨凌西桥村出现缺铁黄化的猕猴桃园为研究对象,采用土壤诊断和叶片诊断等方法确定黄化的原因,并以清水为对照,喷施不同铁制剂(硫酸亚铁、柠檬酸铁、复合氨基酸铁、乳酸亚铁和腐殖酸铁)进行矫治,检测其对猕猴桃叶片叶绿素和有效铁含量及果实品质的影响.结果表明,猕猴桃黄化原因不仅仅是由于土壤有效铁含量低,还与植株吸收能力不同有关.由于植株过多吸收P、K、Zn

  19. Análise espaço-temporal da clorose variegada dos citros no Noroeste do Paraná, com uso de PCR para detecção de Xylella fastidiosa = Spatio-temporal analysis of the citrus variegated chlorosis (CVC in the Northwest of Paraná, using PCR for detection of Xylella fastidiosa

    Directory of Open Access Journals (Sweden)

    William Mário de Carvalho Nunes

    2006-07-01

    Full Text Available A citricultura é afetada por inúmeras doenças, como a clorose variegada do citros (CVC, causada pela bactéria Xylella fastidiosa. O objetivo deste trabalho foi determinar a distribuição espacial da doença dentro de pomares comerciais do Noroeste do Paraná com o uso de métodos moleculares. Foram selecionados pomares sintomáticos para CVC com as variedades ‘Pêra’, ‘Valência’ e ‘Folha Murcha’ (Citrus sinensis Osbeck. Foram marcadas para cada variedade, 4 plantas-referência positivas para CVC (por sintomas e análise molecular e 8 plantas ao redor de cada uma das plantas-referência foram amostradas, num total de 36 plantas por variedade. Realizou-se o teste da Reação da Polimerase em Cadeia (PCR para detecção da bactéria e na mesma época foram conduzidas avaliações visuais de sintomas de CVC. Os resultados da análise temporal, utilizando-se os modelos Monomolecular, Logístico e Gompertz, apontaram o modelo Logístico como o que melhor se ajustou para descrever o comportamento da doença no tempo, para todas as variedades estudadas. Observou-se que o comportamento espacial da doença diferiu quando a mesma área foiavaliada pelos métodos visual e molecular, resultando em uma diferença no padrão espacial das áreas avaliadas. Portanto, ambos os métodos empregados, sintomas e PCR, foram capazes de constatar asmudanças no padrão espacial apresentado, sendo que a análise molecular (PCR foi mais sensível para detectar as mudanças ocorridas.Countless diseases affect the citriculture, as the citrus variegated chlorosis (CVC which is caused by the bacteria Xylella fastidiosa.The aim of this work was to determine the space distribution of the disease inside commercial orchards in the Northwest of Paraná, using molecular methods. Symptomatic orchards were selected for CVC with the varieties 'Pêra', 'Valência' and 'Folha Murcha' (Citrus sinensis Osbeck. For each variety, 4 positive reference-plant for CVC

  20. Alternation of host plants as a survival mechanism of leafhoppers Dilobopterus costalimai and Oncometopia facialis (Hemiptera: Cicadellidae, vectors of the Citrus Variegated Chlorosis (CVC Alternância de hospedeiros como mecanismo de sobrevivência das cigarrinhas Dilobopterus costalimai e Oncometopia facialis (Hemiptera: Cicadellidae, vetoras da Clorose Variegada dos Citros (CVC

    Directory of Open Access Journals (Sweden)

    José Maria Milanez

    2001-12-01

    Full Text Available Dilobopterus costalimai (Young and Oncometopia facialis (Signoret are two of the most important species of citrus leafhoppers, vectors of bacterium Xylella fastidiosa which causes the Citrus Variegated Chlorosis (CVC disease. To develop a rearing technique for these species under laboratory conditions, the egg laying preference and nymph development were studied in different breeding systems: Rangpur lime (Citrus limonia and "falso boldo" (Vernonia condensata as host plants. Trials were set up in a randomized block design with three treatments (n=8. Females of D. costalimai had particular preference for ovipositing on Rangpur lime leaves while O. facialis females placed a higher number of eggs on "falso boldo", but it did not differ statistically from the Rangpur lime. The nymphal viability of D. costalimai was null in Rangpur lime and 58% in "falso boldo". For O. facialis the nymphal viability was 25 and 78% in Rangpur lime and "falso boldo", respectively. "Falso boldo" is more suitable as a host plant to rear the two species of citrus leafhoppers. The alternation of host plants seems to be an important survival mechanism of the CVC-vector species, as shown in natural conditions.Dilobopterus costalimai (Young e Oncometopia facialis (Signoret são duas das mais importantes espécies de cigarrinhas dos citros, transmissoras da bactéria Xylella fastidiosa causadora da doença conhecida como Clorose Variegada dos Citros (CVC. Com o objetivo de se desenvolver uma técnica de criação destas espécies, em condições de laboratório, estudou-se a preferência por postura e o desenvolvimento ninfal, em diferentes sistemas de criação, tendo como plantas hospedeiras limão cravo (Citrus limonia e falso boldo (Vernonia condensata. O delineamento experimental foi em blocos casualizados com três tratamentos e oito repetições. Fêmeas de D. costalimai tiveram acentuada preferência para ovipositar em folhas de limão cravo, enquanto que fêmeas de O

  1. Nonlinear models for describing the Citrus Variegated Chlorosis in groves of two counties at northwestern Paraná state, Brazil = Modelo não-linear para a curva de progresso de incidência da Clorose Variegada dos Citros (CVC em dois municípios da região noroeste do Estado do Paraná

    Directory of Open Access Journals (Sweden)

    Clara Matiko Ueda

    2010-10-01

    Full Text Available In Brazil, the production of sweet oranges has been threatened by the Citrus Variegated Chlorosis (CVC incited by the gram-negative bacterium Xylella fastidiosa (Wells. Commercial citrus groves in two counties at the Northwestern Paraná state were evaluated to estimate the disease progression by using parameterizations of nonlinear models. Groves of Citrus sinensis Osbeck, variety “Pêra”, “Valência”, “Natal” and “Folha Murcha” had all the plants evaluated for the presence of disease symptoms. Thereafter, different parameterizations of the Logistic and Gompertz models were fitted to these data. The goodness of fit was evaluated by the intrinsic (IN and parameter-effects (PE curvatures of Bates and Watts, the bias of Box and the Hougaard measures of skewness. In Loanda, the best model was the Fermi-Dirac, and in Nova Esperança the data were best fitted to the parameterization L5, which is also a parameterization from the Logistic model.A citricultura é afetada por diversas doenças, dentre as quais a Clorose Variegada dos Citros (CVC causada pela bactéria Xylella fastidiosa (Wells. Para a região noroeste do Estado do Paraná, onde foi avaliada a CVC, propõe-se encontrar modelos não-lineares de curvas de progresso de incidência da CVC que representem o percentual de plantas acometidas pela doença. Para avaliar o comprometimento dos pomares com relação à doença, foram escolhidos pomares comerciais em dois municípios, onde foi determinada a proporção de plantas doentes. Foram selecionados talhões de laranja doce (Citrus sinensis Osbeck nas variedades “Pêra”, “Valência”, “Natal” e “Folha Murcha” e a avaliação de todas as plantas do talhão foi realizada visualmente em relação à presença ou à ausência de sintomas de CVC. Para estimar o modelo que melhor se ajustou aos dados de progresso da proporção da doença em cada talhão, foram considerados modelos não-lineares decrescimento sigmoidal

  2. 75 FR 17289 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Science.gov (United States)

    2010-04-06

    ..., eradicate, or prevent the introduction or dissemination of a biological control organism, plant pest, or... dissemination of a biological control organism, plant pest, or noxious weed within the United States. (b... introduction or dissemination of plant pests and noxious weeds into the United States. The regulations...

  3. 76 FR 8603 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Science.gov (United States)

    2011-02-15

    ... disease of citrus and referred to below as HLB) is considered to be one of the most serious citrus... world where the disease is endemic, citrus trees decline and die within a few years and may never.... Manjunath. Asian Citrus Psyllids (Sternorrhyncha: Psyllidae) and Greening Disease of Citrus: A...

  4. Strictly NO3- Nutrition Alleviates Iron Deficiency Chlorosis in Arabidopsis thaliana Plants

    Directory of Open Access Journals (Sweden)

    Najoua Msilini

    2014-03-01

    Full Text Available The effects of NO3- nutrition on iron deficiency responses were investigated in Arabidopsis thaliana. Plants were grown with or without 5 µM Fe, and with NO3- alone or a mixture of NO3- and NH4+. The results indicated that, NO3- nutrition induced higher dry matter production, regardless the Fe concentration. Fe deficiency reduced growth activity, photosynthetic pigment concentration and Fe content of plants, whatever the N forms. This decrease was more pronounced in plants grown with mixed N source; those plants presented the highest EL and MDA and anthocyanin contents compared to plants grown under Fe sufficient conditions. In iron free-solutions, with NO3- as the sole nitrogen source, enhanced FC-R activity in the roots was observed. However, in the presence of NH4+, plants displayed some decrease in in FC-R and PEPC activities. The presence of NH4+ modified typical Fe stress responses in Arabidopsis thaliana plants.

  5. Gene Disruption by Homologous Recombination in the Xylella fastidiosa Citrus Variegated Chlorosis Strain

    Science.gov (United States)

    Gaurivaud, Patrice; Souza, Leonardo C. A.; Virgílio, Andrea C. D.; Mariano, Anelise G.; Palma, Renê R.; Monteiro, Patrícia B.

    2002-01-01

    Mutagenesis by homologous recombination was evaluated in Xylella fastidiosa by using the bga gene, coding for β-galactosidase, as a model. Integration of replicative plasmids by homologous recombination between the cloned truncated copy of bga and the endogenous gene was produced by one or two crossover events leading to β-galactosidase mutants. A promoterless chloramphenicol acetyltransferase gene was used to monitor the expression of the target gene and to select a cvaB mutant. PMID:12200328

  6. Pulsing with low concentration gibberellin plus benzyladenine or commercial floral preservatives affect postharvest longevity, quality, and leaf chlorosis of cut lilies and gladioli

    DEFF Research Database (Denmark)

    Ahmad, I.; Favero, B.T.; Dole, J.M.

    2014-01-01

    Effects of pulsing with different concentrations of gibberellin plus benzyladenine (GA4+7 + BA), a proprietary mixture of GA4+7 plus BA in a commercial floral preservative (GA4+7 + BA + preservative), or a propriety mixture of sugar plus acidifier developed for bulbous flowers (floral bulb preser...

  7. The Content of Mg, K and Ca Ions in Vine Leaf under Foliar Application of Magnesium on Calcareous Soils

    OpenAIRE

    David Gluhić; Mirjana Herak Ćustić; Marko Petek; Lepomir Čoga; Sanja Slunjski; Marijan Sinčić

    2009-01-01

    Chlorosis frequently occurs in vine production on calcareous soils, which is usually attributed to high calcium concentrations in soil. If symptoms appear on older leaves, it is taken that chlorosis is caused by a deficit of Mg2+ ions. A method of preventing chlorosis is foliar application of magnesium; however, uncontrolled application can lead to imbalance with potassium and calcium ions. The research objective was to find out whether foliar application of magnesium could solve the problem ...

  8. Flutuação populacional de espécies de cigarrinhas transmissoras da clorose variegada dos citros (CVC em Viçosa-MG Population dynamics of sharpshooters species transmitter of citrus variegated chlorosis (CVC in Viçosa-MG

    Directory of Open Access Journals (Sweden)

    Dierlei dos Santos

    2005-08-01

    Full Text Available Os objetivos deste trabalho foram avaliar a presença e a dinâmica populacional, ao longo do ano, de cigarrinhas transmissoras da CVC, no município de Viçosa - MG. As coletas foram realizadas no período de agosto de 2003 a julho de 2004, com auxílio de armadilhas adesivas amarelas e com rede entomológica (puçá. Das onze espécies comprovadamente capazes de transmitir a CVC, foram encontradas nove. O número total de cigarrinhas capturadas foi de 2.966, sendo 2.805 nas armadilhas e 161 no puçá. As três espécies da família Cicadellidae mais expressivas em número de insetos foram Bucephalogonia xanthophis (36,6% capturados na rede entomológica e 34,7% na armadilha, Dilobopterus costalimai (9,9% capturados na rede entomológica e 11,3% na armadilha e Acrogonia citrina (6,8% capturados na rede entomológica e 7,4% na armadilha. No mês de novembro, foram coletadas 378 cigarrinhas, correspondendo ao mês de maior incidência, sendo que 292 dessas foram coletadas na primeira quinzena, concorrendo para um pico populacional. Não houve diferença significativa entre o número médio de cigarrinhas coletadas no interior e na periferia da área.The objectives of this work were to evaluate the presence and the population dynamics of Citrus CVC transmitter sharpshooters along the year in the municipality of Viçosa- MG. The sharpshooter populations were monitored in the period of August 2003 to July 2004 using yellow adhesive traps and entomologic nets. During this period 2966 sharpshooters were captured and identified. Among eleven species known as CVC transmitters, nine were found in the region. The three most expressive species in number found were Bucephalogonia xanthophis (36,6% captured in entomological net and 34,7% in the trap, Dilobopterus costalimai (9,9% captured in entomological net and 11,3% in the trap and Acrogonia citrina (6,8% captured in entomological net and 7,4% in the trap. The largest incidence of sharpshooters occurred in November (378 insects, with the population reaching the pick in the first fifteen days of the month (292 insects. There was not significant difference among the medium number of sharpshooters collected in the interior and in the periphery of the area.

  9. The Complete Nucleotide Sequence and Genome Organization of Tomato Cholrosis Virus: A Distinct Crinivirus most Closely Related to Lettuce Infectious Yellow Virus

    Science.gov (United States)

    Tomato infectious chlorosis virus (TICV), affects tomato production in many temperate to subtropical parts of the world where production is impacted by the presence of the greenhouse whitefly (Trialeurodes vaporariorum). Symptoms include interveinal yellowing, and leaves become thickened and crispy,...

  10. Clorose férrica induzida pelo calcário

    OpenAIRE

    Pestana, Maribela; A. de Varennes; Correia, Pedro José

    2014-01-01

    Iron chlorosis is one of the most common and difficult to control problems in crops grown on calcareous soils. In alkaline soils, which represent one third of the Earth surface, the bicarbonate ion prevails and is a major induction factor of iron chlorosis. As a result, alkalinity limits Fe bioavailability in the soil solution, Fe reduction and assimilation, as well as transport and uptake within the plant. Due to this nutritional imbalance, plants develop different response strat...

  11. Crop Response to Glyphosate Trimesium Sulphosate

    OpenAIRE

    Danijela PAVLOVIC; VRBNICANIN, Sava; Carl REINHARDT

    2013-01-01

    Glyphosate may cause injury to non-target plants. The first detectable symptom after glyphosate treatment is the growth inhibition, followed by noticeable yellowing (chlorosis) of the treated tissue. Five to ten days after the treatment, the chlorosis turns into necrosis and the plants begin to die. Greenhouse research was conducted in 2007 to investigate the response of glyphosate resistant (GR) soybeans PAN 520 line and non-glyphosate resistant EGRET line of soybeans to glyphosate trimesium...

  12. Chemical composition on cacao leaves infected by viruses

    Energy Technology Data Exchange (ETDEWEB)

    Mustafa, M.; Delilah, M.; Syafrul, L.; Suryadi

    1980-09-01

    Chemical analysis on cacao leaves that have chlorosis spots caused by cacao swollen shoot viruses were carried out. It can be shown that leaves with chlorosis spots contain less chlorophyl and lipides than those without, but both do not show any significant difference in the concentration of water, glucose, saccharides, amino acid and proteins. It can be concluded that transport systems in the infected leaves are good so that the water and saccharides distribution in them are not disturbed.

  13. Iron deficiency in plants: An insight from proteomic approaches

    Science.gov (United States)

    Iron (Fe) deficiency chlorosis is a major nutritional disorder for crops growing in calcareous soils, and causes decreases in vegetative growth as well as marked yield and quality losses. With the advances in mass spectrometry techniques, a substantial body of knowledge has arisen on the changes in ...

  14. Leaf rust resistance in wheat line RL6062 is an allele at the Lr3 locus

    Science.gov (United States)

    RL6062, a 'Thatcher' backcross line of wheat (Triticum aestivum L.) has resistance to leaf rust (caused by Puccinia triticina) derived from a line of common wheat from Iran. RL6062 has an intermediate infection type (IT) of small to moderate uredinia surrounded by distinct chlorosis. RL6062 was cros...

  15. Two MATE Proteins Play a Role in Iron Efficiency in Soybean

    Science.gov (United States)

    Iron is a necessary but often limiting nutrient for plant growth and development. Soybeans grown on the high-pH calcareous soils are especially prone to developing iron deficiency chlorosis and suffering the resultant yield losses. Once iron is transported into the root, it must be translocated from...

  16. Setting good practices to assess the efficiency of iron fertilizers.

    Science.gov (United States)

    El-Jendoubi, Hamdi; Melgar, Juan Carlos; Alvarez-Fernández, Ana; Sanz, Manuel; Abadía, Anunciación; Abadía, Javier

    2011-05-01

    The most prevalent nutritional disorder in fruit tree crops growing in calcareous soils is Fe deficiency chlorosis. Iron-deficient, chlorotic tree orchards require Fe-fertilization, since chlorosis causes decreases in tree vegetative growth as well as fruit yield and quality losses. When assessing the effectiveness of Fe-fertilizers, it is necessary to use sound practices based in the state-of-the art knowledge on the physiology and biochemistry of Fe deficiency. This review provides an overview on how to carry out the assessment of the efficiency of Fe-fertilizers, discussing common errors found in the literature, outlining adequate procedures and giving real examples of practical studies carried out in our laboratory in the past decade. The review focuses on: i) the design of Fe-fertilization experiments, discussing several issues such as the convenience of using controlled conditions or field experiments, whether fertilizer assessment experiments should mimic usual fertilization practices, as well as aspects regarding product formulations, dosages, control references and number of replicates; ii) the assessment of chlorosis recovery upon Fe-fertilization by monitoring leaf chlorophyll, and iii) the analysis of the plant responses upon Fe-fertilization, discussing the phases of leaf chlorosis recovery and the control of other leaf nutritional parameters.

  17. The effects of Fe-chelate type and PH on substrate grown roses

    NARCIS (Netherlands)

    Voogt, W.; Sonneveld, C.

    2009-01-01

    Substrate grown roses appear to be susceptible to chlorosis, which indicates problems with Fe or Mn uptake and hence yield reduction. In common practice this problem is often treated by the addition of extra Fe-chelate, or the use of Fe-EDDHA instead of Fe-DTPA. In previous tests, it was shown that

  18. Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants

    NARCIS (Netherlands)

    Araujo, W.L.; Marcon, J.; Maccheroni, jr. W.; Elsas, van J.D.; Vuurde, van J.W.L.; Azevedo, de J.L.

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independen

  19. Iron partitioning at an early growth stage impacts iron deficiency responses in soybean plants (Glycine max L.)

    NARCIS (Netherlands)

    Santos, Carla S.; Roriz, Mariana; Pinto de Carvalho, S.M.P.; Vasconcelos, Marta W.

    2015-01-01

    Iron (Fe) deficiency chlorosis (IDC) leads to leaf yellowing, stunted growth and drastic yield losses. Plants have been differentiated into ‘Fe-efficient’ (EF) if they resist to IDC and ‘Fe-inefficient’ (IN) if they do not, but the reasons for this contrasting efficiency remain elusive. We grew E

  20. Aster yellows group (16SrI), subgroups 16SrI-A and 16SrI-B, phytoplasmas associated with lettuce yellows in Texas

    Science.gov (United States)

    In 2013, an epidemic of lettuce yellows occurred in the Winter Garden region of Texas. The infected plants were stunted with blanching and chlorosis in young heart leaves. A total of thirteen samples, including three apparently asymptomatic, from Romaine and leaf lettuce cultivars, on two different...

  1. Segregation of unknown signaling components in potato complicates marker-assisted selection for Ve-mediated Verticillium resistance

    Science.gov (United States)

    Verticillium wilt (VW), caused primarily by soil-borne fungi Verticillium dahliae Kleb and V. albo-atrum Reinke and Berthold is characterized by unilateral wilting of leaves, chlorosis, and premature senescence. VW is mainly controlled by fumigating fields with metam sodium, which has negative econo...

  2. Detection and quantification of Bremia lactucae by spore trapping and quantitative PCR

    Science.gov (United States)

    Bremia lactucae causes the characteristic vein-delimited lesions, leaf chlorosis and necrosis and adversely affects marketability of lettuce. The disease has been managed with a combination of host resistance and fungicide applications with mixed success over the years. Fungicide applications are ro...

  3. Fatty acid profiling to characterize California strains of Xylella fastidiosa

    Science.gov (United States)

    Different strains of Xylella fastidiosa cause diseases such as Pierce’s disease of grapevine, citrus variegated chlorosis, and bacterial leaf scorch of hardwoods. However, more research is needed to better define subspecies and strains of X. fastidiosa to improve both regulations concerning this bac...

  4. Xylella fastidiosa is associated with reduced yield and altered fruit quality in a rabbiteye blueberry orchard in Louisiana but does not appear to spread rapidly

    Science.gov (United States)

    Xylella fastidiosa is a bacterial pathogen that causes diseases such as Pierce’s disease of grape, bacterial leaf scorch of shade trees, and citrus variegated chlorosis. Work by researchers in Georgia and Florida has shown that it is the cause of bacterial leaf scorch of Southern highbush blueberrie...

  5. [Photochemical activity, spectral properties, and structure of chloroplasts in leaves of Pisum sativum L. under iron deficit and root anaerobiosis].

    Science.gov (United States)

    Ladygin, V G

    2005-01-01

    A combined effect of iron deficit and root anaerobiosis on the biochemical composition, functional activity, and structure of chloroplasts in pea leaves was studied. These factors are shown to affect the chlorophyll accumulation, causing leaf chlorosis. Iron deficit makes itself evident in the chlorosis of top leaves. In the case of root anaerobiosis, chlorosis damages lower plant layers. The destructive effects are summarized under the influence of both factors. The light-harvesting complexes of photosystems are reduced to a greater degree under iron deficit; under root anaerobiosis, complexes of reaction centers of photosystem I and II are reduced. Nevertheless, even under the combined effect of these factors, all pigment-protein complexes and their functional activities are preserved in yellow leaves. The ultrastructure of chloroplasts is gradually reduced in the course of developing chlorosis. In the begging, intergranal sites of thylakoids are destroyed, which is typical for iron deficit, then granal sites are broken. However, even in yellow and almost white leaves, small thylakoids capable of forming stacking and small grana of 2-3 thylakoids are preserved. The destructive effects are summarized due to different mechanisms of action of iron deficit and root anaerobiosis on the structure and function of leaves under their combined effect. PMID:15759507

  6. [Structural and functional organization of chloroplasts in leaves of Pisum sativum L. under conditions of root hypoxia and iron deficiency].

    Science.gov (United States)

    Ladygin, V G; Semenova, G A

    2003-01-01

    A combined effect of iron deficiency and root hypoxia on the biochemical composition activity and structure of chloroplasts in pea leaves have been studied. Both factors are shown to affect the accumulation of chlorophyll causing leaf chlorosis. At iron deficiency chlorosis occurs from the top of plant leaves. At root hypoxia chlorosis starts from the lower strata. At a combined action of both factors the destructive effects are summarized. It was established that light-harvesting complexes of photosystems were reduced stronger at iron deficiency, while complexes of reaction centers of photosystem I and photosystem II are lessened at root hypoxia. Nevertheless, even at a combined effect of both factors yellow leaves preserved small amounts of any pigment-protein complexes and their functional activities. The ultrastructure of chloroplasts during leaf chlorosis was gradually reduced. At first, intergranal sites of thylakoids and then granal ones were destroyed, that was typical of iron deficiency. However, even yellow and almost white leaves kept small thylakoids, capable of forming stacking and small grana made of 2-3 thylakoids. It has been concluded that the destructive effects are summarized due to different kinds of action of iron deficiency and root hypoxia on the structure and functioning of leaves at their combined action. PMID:15216630

  7. Response of broccoli and cabbage hybrid cultivars to clomazone

    Science.gov (United States)

    Clomazone herbicide (Command 3ME) is registered for cabbage in the U.S., but not for other cultivar groups within Brassica oleracea. Cabbage cultivars vary in clomazone tolerance, and recommended use rates can cause severe foliar chlorosis and yield reduction to susceptible cultivars. The objectiv...

  8. Development of an assay for rapid detection of the lettuce downy mildew pathogen, Bremia lactucae

    Science.gov (United States)

    Downy mildew of lettuce, caused by Bremia lactucae, causes chlorosis on leaves and adversely affects marketability. Though downy mildew on lettuce can be controlled by fungicide applications, it is costly to routinely apply fungicides to prevent the establishment of downy mildew. Repeated use of the...

  9. Iron fertilization with FeEDDHA : the fate and effectiveness of FeEDDHA chelates in soil-plant systems

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.

    2010-01-01

    Iron deficiency chlorosis is a nutritional disorder in plants which reduces crop yields both quantitatively and qualitatively, and causes large economic losses. It occurs world-wide, predominantly in plants grown on calcareous soils, as a result of a limited bioavailability of iron related to the po

  10. Nutritional status of the cauliflower cultivar 'verona' grown with omission of out added macronutrients.

    Science.gov (United States)

    Bianco, Matheus Saraiva; Cecílio Filho, Arthur Bernardes; de Carvalho, Leonardo Bianco

    2015-01-01

    Knowledge of plant nutritional status allows an understanding of the physiological responses of plants to crop fertilization. A hydroponic experiment evaluated the symptoms of macronutrient deficiency in cauliflower 'Verona' and determined: a) the macronutrient contents of foliar tissues when visual symptoms were observed, b) macronutrients content of foliar and inflorescence tissues at harvest. The effect of nutrient deficiency on inflorescence mass was also evaluated. Nitrogen deficiency caused chlorosis followed by purple color in the old leaves, while P deficiency caused only chlorosis in old leaves. Chlorosis at the edge of old leaves progressing to the center of the leaves was observed with the omission of K, and after was observed necrosis in the chlorotic areas. Ca deficiency caused tip burn in new leaves, while Mg deficiency caused internerval chlorosis in old leaves. The omission of each macronutrient reduced inflorescence dry matter. This deleterious effect was larger for N, P, and K deficiencies, reducing inflorescence dry matter by 87, 49, and 42%, respectively. When the nutrient solutions without N, P, K, Ca, or Mg were supplied to cauliflower plants, the macronutrient contents at harvest were 8.8, 0.6, 3.5, 13.0, and 0.8 g kg-1 in the foliar tissues and 27.3, 2.2, 21.6, 1.1, and 0.7 g kg-1 in the inflorescence tissues, respectively. PMID:25856380

  11. Copper exposure interferes with the regulation of the uptake, distribution and metabolism of sulfate in Chinese cabbage

    NARCIS (Netherlands)

    Shahbaz, Muhammad; Tseng, Mei Hwei; Stuiver, C. Elisabeth E.; Koralewska, Aleksandra; Posthumus, Freek S.; Venema, Jan Henk; Parmar, Saroj; Schat, Henk; Hawkesford, Malcolm J.; De Kok, Luit J.

    2010-01-01

    Exposure of Chinese cabbage (Brassica pekinensis) to enhanced Cu(2+) concentrations (1-10 mu M) resulted in leaf chlorosis, a loss of photosynthetic capacity and lower biomass production at >= 5 mu M. The decrease in pigment content was likely not the consequence of degradation, but due to hindered

  12. First report of 'Candidatus Liberibacter solanacearum' on tomato in Honduras

    Science.gov (United States)

    In April of 2012, tomato plants grown in several departments of Honduras, were observed with symptoms resembling those of “Candidatus Liberibacter solanacearum” (Lso) infection. The symptoms include overall chlorosis, severe stunting, leaf cupping, excessive branching of axillary shoots, and leaf pu...

  13. First report of "Candidatus Liberibacter solanacearum" infecting eggplant in Honduras

    Science.gov (United States)

    In May of 2012, eggplant (Solanum melongena) plants in an experimental research plot located at Zamorano in the Department of Francisco Morazán, Honduras, were observed with symptoms that included leaf chlorosis and cupping, overall stunting, and production of small and malformed fruits. The researc...

  14. THE ENDOPHYTE CURTOBACTERIUM FLACCUMFACIENS REDUCES SYMPTOMS CAUSED BY XYLELLA FASTIDIOSA IN CATHARANTHUS ROSEUSAN ENDOPHYTIC BACTERIUM FROM CITRUS

    Science.gov (United States)

    Citrus variegated chlorosis (CVC) is a disease of sweet orange (Citrus sinensis (L.)) caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that can infect all sweet orange cultivars. Sweet orange trees are sometimes observed to be infected by Xylella fastidiosa without showing seve...

  15. THE ROLE OF TYLOSES IN CROWN HYDRAULIC FAILURE OF MATURE WALNUT TREES AFFLICTED WITH APOPLEXY DISORDER

    Science.gov (United States)

    In the Central Valley of California, mature walnut trees afflicted with apoplexy disorder exhibit rapid and complete canopy defoliation within a few weeks of symptom initiation. Symptoms are typically found throughout the entire canopy and are initially expressed as wilting and chlorosis followed b...

  16. Genome-wide association analysis in spring wheat identifies QTL associated with resistance to a novel isolate of Pyrenophora tritici-repentis

    Science.gov (United States)

    Tan spot, caused by Pyrenophora tritici-repentis, is an important disease of wheat worldwide. Pathogenic races of P. tritici-repentis have been identified based on their ability to induce tan necrosis and/or chlorosis symptoms on differential wheat genotypes. Race 1 causes necrosis and extensive chl...

  17. Effect of Soil Moisture on Release of Low-MolecularWeight Organic Acids in Root Exudates and the Accumulation of Iron in Root Apoplasm of Peanut

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A three-compartments rhizobox was designed and used to study the low-molecular-weight organic acids in root exudates and the root apoplastic iron of "lime-induced chlorosis" peanut grown on a calcareous soil in relation to different soil moisture conditions. Results showed that chlorosis of peanuts developed under condition of high soil moisture level (250 g kg-1), while peanuts grew well and chlorosis did not develop when soil moisture was managed to a normal level (150 g kg-1). The malic acid, maleic acid and succinic acid contents of chlorotic peanut increased by 108.723, 0.029 and 22.446μg cm-2, respectively,compared with healthy peanuts. The content of citric acid and fumaric acid also increased in root exudates of chlorotic peanuts. On Days 28 and 42 of peanut growth, the accumulation of root apoplastic iron in chlorotic peanuts was higher than that of healthy peanuts. From Day 28 to Day 42, the mobilization percentages of chlorotic peanuts and healthy peanuts to root apoplastic iron were almost the same, being 52.4% and 52.8%,respectively, indicating that the chlorosis might be caused by the inactivation of iron within peanut plant grown on a calcareous soil under high soil moisture conditions.

  18. The Content of Mg, K and Ca Ions in Vine Leaf under Foliar Application of Magnesium on Calcareous Soils

    Directory of Open Access Journals (Sweden)

    David Gluhić

    2009-06-01

    Full Text Available Chlorosis frequently occurs in vine production on calcareous soils, which is usually attributed to high calcium concentrations in soil. If symptoms appear on older leaves, it is taken that chlorosis is caused by a deficit of Mg2+ ions. A method of preventing chlorosis is foliar application of magnesium; however, uncontrolled application can lead to imbalance with potassium and calcium ions. The research objective was to find out whether foliar application of magnesium could solve the problem of chlorosis, and whether magnesium affects ion interactions with potassium and calcium. The fertilizing trial was set up in vineyards, on anthropogenized rigosols, with different contents of available lime in soil (< 20, 25 and 30 % CaO. Fertilizer was applied three times during the growing period, in a total amount of 2500 g Mg/ha. According to the results, foliar application of magnesium can solve the problem of chlorosis only on soils with a lower lime content (< 20 % CaO. Magnesium concentrations in dry leaf ranged from 0.25 % (beginning of growing period to 0.64 % (post harvest, which is in agreement with literature data. On soils with a high lime content, negative correlation was determined between Mg and K ions in the leaf (r = -0.78. Although correlation between Mg and Ca in plant was positive (r = +0.61 to +0.90 during whole grape vine vegetative period, determined high ratios between Ca and Mg, especially during summer (12.4, indicated that Ca was dominant ion in plant disturbing K and Mg physiological roles.

  19. Crop Response to Glyphosate Trimesium Sulphosate

    Directory of Open Access Journals (Sweden)

    Danijela PAVLOVIC

    2013-12-01

    Full Text Available Glyphosate may cause injury to non-target plants. The first detectable symptom after glyphosate treatment is the growth inhibition, followed by noticeable yellowing (chlorosis of the treated tissue. Five to ten days after the treatment, the chlorosis turns into necrosis and the plants begin to die. Greenhouse research was conducted in 2007 to investigate the response of glyphosate resistant (GR soybeans PAN 520 line and non-glyphosate resistant EGRET line of soybeans to glyphosate trimesium sulphosate and to evaluate soybeans injury to help in weed resistance detection. The methods used to detect changes were dose response test, HPLC measurement based on glyphosate induced accumulation of shikimate, and morpho-anatomical changes (light and electron microscopy. Damaged chloroplasts are a clear indication of a glyphosate injury. If the injury rating is related to increased shikimate levels, there is greater certainty that differences among biotypes are due to glyphosate tolerance.

  20. Physiological and ecological studies of the vegetation on ore deposits. I. Zinc flora and indicator plants on the 2nd Yunwha mine. [Sedum sp. ; Dianthus sinensis

    Energy Technology Data Exchange (ETDEWEB)

    Chang, N.K.; Chang, S.M.

    1977-01-01

    During the period of 1975-76, a survey was carried out to find out zinc indicators in the natural vegetation in Korea. The symptoms of chlorosis were observed in flowering plants in the areas of zinc outcrop of Wolgok-A, Seokgok-9, and Sowolgok. Although 28 species were found to be chlorotic, the total quantity of chlorotic foliage observed was small. Reasons for chlorosis in the areas of zinc ore deposits is considered as effects of zinc, lead, copper and calcium ions. Sedum sp. and Dianthus sinensis were confined to soil containing more than exchangeable zinc of 30 ppm and to accumulation in the plants contained at least 1,300-14,000 ppm of zinc. Therefore, Sedum sp. and Dianthus sinensis might be used as zinc indicators in Korea. 12 references, 1 figure, 5 tables.

  1. Multilocus Simple Sequence Repeat Markers for Differentiating Strains and Evaluating Genetic Diversity of Xylella fastidiosa

    OpenAIRE

    Lin, Hong; Civerolo, Edwin L; Hu, Rong; Barros, Samuel; Francis, Marta; Walker, M Andrew

    2005-01-01

    A genome-wide search was performed to identify simple sequence repeat (SSR) loci among the available sequence databases from four strains of Xylella fastidiosa (strains causing Pierce's disease, citrus variegated chlorosis, almond leaf scorch, and oleander leaf scorch). Thirty-four SSR loci were selected for SSR primer design and were validated in PCR experiments. These multilocus SSR primers, distributed across the X. fastidiosa genome, clearly differentiated and clustered X. fastidiosa stra...

  2. Pest and disease monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Straw, Nigel; Lonsdale, David [Forest Research, Farnham (United Kingdom)

    2000-07-01

    This paper summaries the findings of surveys of pests and diseases carried out at pure and mixed plots of willow and poplar varieties twice a year during each growing season. The main causes of damage recorded were leaf rust, defoliation by insects, and leaf disease, distortion and chlorosis as well as frost damage, aphid infestation, and shoot dieback. Leaf rust for willow and poplar clones are plotted, and details of leaf rust and defoliation in pure and mixed plots are tabulated.

  3. Role of Zinc in Plant Nutrition- A Review

    OpenAIRE

    Hafeez, B.; Khanif, Y. M.; Saleem, M.

    2013-01-01

    Zinc is plant micronutrient which is involved in many physiological functions its inadequate supply will reduce crop yields. Zinc deficiency is the most wide spread micronutrient deficiency problem, almost all crops and calcareous, sandy soils, peat soils, and soils with high phosphorus and silicon are expected to be deficient. Zinc deficiencies can affect plant by stunting its growth, decreasing number of tillers, chlorosis and smaller leaves, increasing crop maturity period, spikelet steril...

  4. Identification of rice varieties tolerant to photooxidation and shading

    Institute of Scientific and Technical Information of China (English)

    JIAODemao; TONGHongyu; ZHANGTianxi

    1994-01-01

    Long time exposure of rice plants to strong light will cause leaves chlorosis due to photooxidation,while the long time exposure to weak light will do them shading. Six varieties-indica hybrid rice Shanyou 63 and its parents Minghui 63 and Zhenshan 97A, indica-japonica hybrid rice Yayou 2 and its parents 02428 and 3037-were identified for their sensibility to photooxidation and shading at the stem elongation stage.

  5. Detecting Genetic Introgression: High Levels of Intersubspecific Recombination Found in Xylella fastidiosa in Brazil

    OpenAIRE

    Nunney, Leonard; Yuan, Xiaoli; Bromley, Robin E.; Stouthamer, Richard

    2012-01-01

    Documenting the role of novel mutation versus homologous recombination in bacterial evolution, and especially in the invasion of new hosts, is central to understanding the long-term dynamics of pathogenic bacteria. We used multilocus sequence typing (MLST) to study this issue in Xylella fastidiosa subsp. pauca from Brazil, a bacterium causing citrus variegated chlorosis (CVC) and coffee leaf scorch (CLS). All 55 citrus isolates typed (plus one coffee isolate) defined three similar sequence ty...

  6. Genetic characterization of Xylella fastidiosa isolated from citrus and coffee plants Caracterização genética de Xylella fastidiosa isolada de plantas de citros e café

    OpenAIRE

    Vicente Savonitti Miranda; Paulo Roberto Silva Farias; Sérgio Rufo Roberto; Pedro Magalhães Lacava

    2007-01-01

    The Citrus Variegated Chlorosis and the Coffee Leaf Scorch are some of the many destructive diseases caused by Xylella fastidiosa, a gram-negative bacterium limited to the xylem of affected plants. As its genetic characterization is still not well established, different isolates of X. fastidiosa from citrus and coffee were evaluated through RAPD (Random Amplified Polymorphic DNA) technique to characterize and classify these isolates based on similarity coefficients. Sixteen isolates of X. fas...

  7. Characterization and correction of Fe deficiency in strawberry: novel approaches

    OpenAIRE

    Pestana, Maribela; Gama, Florinda; Saavedra, Teresa; Pinto, João Castro; Abadia, Anunciación; A. de Varennes; Correia, Pedro José

    2012-01-01

    Iron (Fe) is abundant in soils and although it is required in small amounts by plants the incidence of iron chlorosis (Fe deficiency) is very common in a number of crops and requires massive soil application of Fe-chelates to correct it. In this work, we present the most important results obtained in several experiments conducted with strawberry to study the physiological and biochemical response mechanisms to Fe deficiency, and the assessment of novel alternatives to control t...

  8. N-Acetylcysteine in Agriculture, a Novel Use for an Old Molecule: Focus on Controlling the Plant–Pathogen Xylella fastidiosa

    OpenAIRE

    Muranaka, Lígia S.; Giorgiano, Thais E.; Marco A. Takita; Forim, Moacir R.; Luis F C Silva; Helvécio D. Coletta-Filho; Machado, Marcos A; De Souza, Alessandra A.

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue use...

  9. Impact of copper toxicity on stone-head cabbage (Brassica oleracea var. capitata) in hydroponics

    OpenAIRE

    Ali, Sajid; Shahbaz, Muhammad; Shahzad, Ahmad Naeem; Khan, Hafiz Azhar Ali; Anees, Moazzam; Haider, Muhammad Saleem; Fatima, Ammara

    2015-01-01

    Arable soils are frequently subjected to contamination with copper as the consequence of imbalanced fertilization with manure and organic fertilizers and/or extensive use of copper-containing fungicides. In the present study, the exposure of stone-head cabbage (Brassica oleracea var. capitata) to elevated Cu2+ levels resulted in leaf chlorosis and lesser biomass yield at ≥2 µ M. Root nitrate content was not statistically affected by Cu2+ levels, although it was substantially decreased at ≥5 µ...

  10. Screening for Barley Waterlogging Tolerance in Nordic Barley Cultivars (Hordeum vulgare L.) Using Chlorophyll Fluorescence on Hydroponically-Grown Plants

    OpenAIRE

    Nils-Ove Bertholdsson

    2013-01-01

    Waterlogging can reduce crop yield by 20%–50% or more, and lack of efficient selection methods is an obstacle in plant breeding. The methods currently used are mainly indices based on germination ability in Petri dishes and leaf chlorosis in plants grown in waterlogged soils. Cultivation in oxygen-depleted nutrient solution is the ultimate waterlogging system. Therefore methods based on root growth inhibition and on fluorescence in plant material hydroponically grown in oxygen-depleted soluti...

  11. Ultrastructural changes in chloroplasts of mesophyll cells of chlorotic and prematurely yellowed leaves of Betula pendula Rothr

    Directory of Open Access Journals (Sweden)

    Krystyna Przybył

    2011-04-01

    Full Text Available The ultrastructure of chloroplasts was studied in mesophyll cells of the leaves of silver birch (Betula pendula showing interveinal chlorosis or premature yellowing, in comparison with leaves without symptoms or exhibiting symptoms of natural senescence. The leaves were collected between May 26 to June 7 and additionally in the September 10-12 from the upper part of the crown, from increments of the past four years. No major difference in ultrastructure of chloroplasts was found between spongy and palisade mesophyll cells. The following senescencerelated changes were observed in chloroplasts of prematurely yellowed leaves and showing inteveinal chlorosis: reduced chloroplast size, degeneration of the membrane systems of thylakoids and increased electron density of plastoglobuli. The most electron dark globules (lipid droplets were found together with starch grains in cells of spongy mesophyll of leaves showing interveinal chlorosis. Abnormal, spherical and rounded chloroplasts with electron-dark inside of thylakoids or the electron-dark stroma between thylakoids were found only in yellowed and chlorotic leaves in spring.

  12. Effects of manganese toxicity on leaf CO{sub 2} assimilation of contrasting common bean genotypes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Lynch, J.P. [The Pennsylvania State Univ., Dept. of Horticulture, PA (United States)

    1997-12-01

    Parameters related to leaf photosynthesis were evaluated in three genotypes of common bean (Phaseolus vulgaris L.) with contrasting tolerance to Mn toxicity. Two short-term studies in solution culture were used to assess the effect of excess Mn on CO{sub 2} assimilation in mature and immature leaves. Mn toxicity decreased total chlorophyll content only in immature leaves, with a consequent reduction of leaf CO{sub 2} assimilation. Mature leaves that showed brown speckles characteristics of Mn toxicity, did not suffer any detriment in their capacity to assimilate CO{sub 2}, at least in a 4-day experiment. Stomatal conductance and transpiration were not affected by the presence of high levels of Mn in leaf tissue. Lower stomatal conductance and transpiration rates were observed only in leaves with advanced chlorosis. Differences among genotypes were detected as increased chlorosis in the more sensitive genotype ZPV-292, followed by A-283 and less chlorosis in the tolerant genotype CALIMA. Since CO{sub 2} assimilation expressed per unit of chlorophyll was not different between high-Mn plants and control plants, we conclude that the negative effect of Mn toxicity on CO{sub 2} assimilation can be explained by a reduction in leaf chlorophyll content. (au) 29 refs.

  13. Ecological studies of plants for the control of environmental pollution. IV. Growth of various plant species as influenced by soil applied cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Cha, J.W.; Kim, B.W.

    1975-03-01

    The relations of the growth response of plants, i.e. 4 species of crops, 12 species of roadside trees and 5 species of horticultural plants to cadmium (Cd) were studied in pot cultures. Growth in dry weight of corn, soybeans, barley, and wheat plants was decreased with an increase in Cd concentration. Damage to corn plants caused by Cd treatment was more or less recovered when it was grown in soil with calcium, but the other three crops did not recover. Although crop plants used here absorbed a small amount of Cd through the roots, the Cd content in the shoots was directly proportionate to the concentration of Cd added to the soil. Additions of calcium and sulfur to soil were sufficient to change the soil pH. The chlorosis on leaves caused by Cd treatment was observed in 2 species such as Euonymus japonica and Rhododendron yedoense out of 5 species of the horticultural plants, especially at 50 ppm of Cd. Euonymus japonica had symptoms of chlorosis and defoliation, and at higher concentrations the symptoms were more severe. At 200 ppm of Cd little damage was observed in Pinus koraiensis and Ginkgo biloba, but severe chlorosis was observed in Robinia pseudoacacia and Sabina chinensis, Buxus koreana, Abies holophylla and Platanus orientalis. Nevertheless, those plants that had serious damage at 200 ppm of Cd showed weakened symptoms by adding calcium to the soil. There were many Cd tolerant species out of the plants used in this experiment, such as Crassula falcata, Chrysanthemum morifolium, Hibiscus syriacus, Ligustrum ovalifolium, Liriodendron tulipeferia, and Lespedeza crytobotrys.

  14. Effector-Triggered Immune Response in Arabidopsis thaliana Is a Quantitative Trait.

    Science.gov (United States)

    Iakovidis, Michail; Teixeira, Paulo J P L; Exposito-Alonso, Moises; Cowper, Matthew G; Law, Theresa F; Liu, Qingli; Vu, Minh Chau; Dang, Troy Minh; Corwin, Jason A; Weigel, Detlef; Dangl, Jeffery L; Grant, Sarah R

    2016-09-01

    We identified loci responsible for natural variation in Arabidopsis thaliana (Arabidopsis) responses to a bacterial pathogen virulence factor, HopAM1. HopAM1 is a type III effector protein secreted by the virulent Pseudomonas syringae strain Pto DC3000. Delivery of HopAM1 from disarmed Pseudomonas strains leads to local cell death, meristem chlorosis, or both, with varying intensities in different Arabidopsis accessions. These phenotypes are not associated with differences in bacterial growth restriction. We treated the two phenotypes as quantitative traits to identify host loci controlling responses to HopAM1. Genome-wide association (GWA) of 64 Arabidopsis accessions identified independent variants highly correlated with response to each phenotype. Quantitative trait locus (QTL) mapping in a recombinant inbred population between Bur-0 and Col-0 accessions revealed genetic linkage to regions distinct from the top GWA hits. Two major QTL associated with HopAM1-induced cell death were also associated with HopAM1-induced chlorosis. HopAM1-induced changes in Arabidopsis gene expression showed that rapid HopAM1-dependent cell death in Bur-0 is correlated with effector-triggered immune responses. Studies of the effect of mutations in known plant immune system genes showed, surprisingly, that both cell death and chlorosis phenotypes are enhanced by loss of EDS1, a regulatory hub in the plant immune-signaling network. Our results reveal complex genetic architecture for response to this particular type III virulence effector, in contrast to the typical monogenic control of cell death and disease resistance triggered by most type III effectors.

  15. Effect of phosphate fertilization on the bioavailability of iron in calcareous soils

    Science.gov (United States)

    Sánchez-Rodríguez, A. R.; del Campillo, M. C.; Barrón, V.; Torrent, J.

    2012-04-01

    Iron (Fe) chlorosis is the most important nutritional problem in sensitive plant species cultivated in calcareous soils, its main symptoms being interveinal yellowing in the younger leaves due to lack of chlorophyll and reduced growth. Fe chlorosis has been related to the content of poorly crystalline Fe oxides in soil. The effect of other nutrients, especially phosphorus (P), is, however, a matter of debate. In this work we examined whether fertilization with P alters the availability of Fe to sensitive plants growing in two different Fe chlorosis-inducing calcareous soils. Phosphate at rates of 0 (control), 25, 50, 100 and 200 mg P kg-1 soil was applied to pots where six-months-old olive trees cv. Arbequina were grown. The experiment lasted three years and took place in a shaded house. Chlorophyll concentration in the young leaves was estimated with the SPAD value (using a Minolta apparatus) three-four times per year. Furthermore, shoot length, dry weight of annual pruning and mineral element concentration were measured at the end of each year. In one of the soils, SPAD and leaf Fe concentration decreased with increasing P dose. However in the other soil, SPAD was not correlated with the rate of applied P. In both soils, potassium and zinc concentrations in plants fertilized with P were lower than those in the control plants. This work was funded by the Spanish Ministry of Science and Innovation, Projects: AGL 2005-06691-C02-01 and AGL 2008-05053-C02-02, and the European Regional Development Funds. ARSR acknowledges the finnancial support from the Spanish Ministry of Education as a fellow of the program "Training of University Teachers" (Formación del Profesorado Universitario, AP2008-04716)

  16. Influence of Sulfur Induced Stress on Oxidative Status and Antioxidative Machinery in Leaves of Allium cepa L.

    OpenAIRE

    Chandra, Neelam; Pandey, Nalini

    2014-01-01

    A pot culture experiment was carried out to assess the effect of sulfur stress on growth, oxidative status, and antioxidative metabolism. Onion plants were treated with three different levels of sulfur, namely, 1.0, 4.0, and 8.0 mM S L−1. Plants raised with 4.0 mM S L−1 represent sufficient growth for the best vegetative yield. Plants supplied with 1.0 and 8.0 mM S L−1 showed retarded growth, chlorosis, and reduction in biomass and photoassimilatory pigments. Tissue sulfur concentration and c...

  17. Ospapst1, a useful mutant for identifying seed purity and authenticity in hybrid rice

    OpenAIRE

    Lv, Qundan; Xu, Jiming; Wu, Ping

    2013-01-01

    The stability and completeness of male sterility is still a challenge in some male sterile rice lines, especially those of photoperiod/thermo-sensitive genic male sterility (P/TGMS). Leaf color marker is a widely practiced approach to reduce the impact of self-pollinated seeds of male sterile lines. The papst1 is a leaf color mutant. The newly emerged leaves of papst1 are chlorosis and have an impaired photosynthesis. But the other agronomic traits, such as germination rate, duration of matur...

  18. Commercial risk-based survey for HLB and implications for efficacy of Citrus Health Management Areas (CHMAs)

    OpenAIRE

    Gottwald, T.; Luo, W.; Riley, T; Parnell, S.

    2014-01-01

    The USDA, APHIS, PPQ has been conducting a risk-based multi-pest survey (MPS) for the past two years.  The initial 6 statewide survey cycles were conducted on a 6 week basis, whereas the subsequent 20 cycles have been conducted on a 3-week basis.  HLB and ACP are the two main pests addressed by the MPS but other citrus pests and diseases, i.e., Asiatic Citrus Canker (ACC), Citrus Leprosis Virus (CLiV), Citrus Black Spot (CBS) and Citrus Variegated Chlorosis (CVC) were also given lesser emphas...

  19. Chemical and Metabolic Aspects of Antimetabolite Toxins Produced by Pseudomonas syringae Pathovars

    Directory of Open Access Journals (Sweden)

    Eva Arrebola

    2011-08-01

    Full Text Available Pseudomonas syringae is a phytopathogenic bacterium present in a wide variety of host plants where it causes diseases with economic impact. The symptoms produced by Pseudomonas syringae include chlorosis and necrosis of plant tissues, which are caused, in part, by antimetabolite toxins. This category of toxins, which includes tabtoxin, phaseolotoxin and mangotoxin, is produced by different pathovars of Pseudomonas syringae. These toxins are small peptidic molecules that target enzymes of amino acids’ biosynthetic pathways, inhibiting their activity and interfering in the general nitrogen metabolism. A general overview of the toxins’ chemistry, biosynthesis, activity, virulence and potential applications will be reviewed in this work.

  20. Bazı Şelatlı Demir Gübrelerinin Şeftalide Demir Eksikliği Klorozuna Etkileri

    OpenAIRE

    AKGÜL, Hüseyin; Kadir UÇGUN; ALTINDAL, Mesut

    2013-01-01

    The peach trees are one of the most sensitive fruit species to iron deficiency. In particular, when the soil has highly pH value and lime content, iron deficiency consists. Iron deficiency causes significantly to loss of yield and quality it also leads seriously death of the tree. Chelated iron fertilizers are used widely to prevent iron deficiency chlorosis. However they don’t indicate the same effect in the same all soil conditions. In this study, the efficiency of EDDHA o-o:3.6, EDDHA o-o:...

  1. Early modern green sickness and pre-Freudian hysteria.

    Science.gov (United States)

    Schleiner, Winfried

    2009-01-01

    In early modern medicine, both green sickness (or chlorosis) and hysteria were understood to be gendered diseases, diseases of women. Green sickness, a disease of young women, was considered so serious that John Graunt, the father of English statistics, thought that in his time dozens of women died of it in London every year. One of the symptoms of hysteria was that women fell unconscious. The force of etymology and medical tradition was so strong that in one instance the gender of the patient seems to have been changed by the recorder to make the case fit medical theory. PMID:20027761

  2. Multiplexed lateral flow microarray assay for detection of citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis pv citri

    Energy Technology Data Exchange (ETDEWEB)

    Cary; R. Bruce (Santa Fe, NM); Stubben, Christopher J. (Los Alamos, NM)

    2011-03-22

    The invention provides highly sensitive and specific assays for the major citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis, including a field deployable multiplexed assay capable of rapidly assaying for both pathogens simultaneously. The assays are directed at particular gene targets derived from pathogenic strains that specifically cause the major citrus diseases of citrus variegated chlorosis (Xylella fastidiosa 9a5c) and citrus canker (Xanthomonas axonopodis pv citri). The citrus pathogen assays of the invention offer femtomole sensitivity, excellent linear dynamic range, and rapid and specific detection.

  3. Antioxidant Status of Vigna mungo L. in Response to Sulfur Nutrition

    OpenAIRE

    Neelam Chandra; Nalini Pandey

    2014-01-01

    Black gram (Vigna mungo L. var. DPU-88-31), an edible legume, was grown at 1, 2, 4, 6, and 8 meq S L−1 to study the effect of deficient and excess level of sulfur on oxidative metabolism. Plants supplied by 4 meq S L−1 showed optimum yield. Sulfur deficient plants (1 and 2 meq S L−1) showed reduction in growth and chlorosis of young leaves. Tissue sulfur and cysteine concentration was increased with increasing sulfur supply. The thresholds for critical concentration of sulfur deficiency and t...

  4. Differential response of corn (Zea mays L. to postemergence application of CGA-136872 at different growth stages

    Directory of Open Access Journals (Sweden)

    Ngouajio, M.

    1991-01-01

    Full Text Available CGA-136872 injured corn more when applied at the 5-leaf stage than when applied at the 7- and 9-leaf stage of corn. Symptoms of herbicide phytotoxicity were primarily stunting and chlorosis. Most injury occurred with high rates (400 g ai/ha and appeared during the first two weeks following treatment. At five weeks after treatment, corn recovery from injury was complete and no yield reduction was recorded. Yield loss occurred in the weedy check, due to competition with johnson grass (Sorghum halepense (L. Pers., giant foxtail (Setaria faberi Herrn., common lambsquarters (Chenopodium album L. and redroot pigweed (Amaranthus retroflexus L.

  5. Iron partitioning at an early growth stage impacts iron deficiency responses in soybean plants (Glycine max L.)

    OpenAIRE

    Carla eSantos; Mariana eRoriz; Carvalho, Susana M. P.; Marta Wilton Vasconcelos

    2015-01-01

    Iron (Fe) deficiency chlorosis (IDC) leads to leaf yellowing, stunted growth and drastic yield losses. Plants have been differentiated into ‘Fe-efficient’ (EF) if they resist to IDC and ‘Fe-inefficient’ (IN) if they do not, but the reasons for this contrasting efficiency remain elusive. We grew EF and IN soybean plants under Fe deficient and Fe sufficient conditions and evaluated if gene expression and the ability to partition Fe could be related to IDC efficiency. At an early growth stage, F...

  6. Effects of ammonium sulfate aerosols on vegetation—II. Mode of entry and responses of vegetation

    Science.gov (United States)

    Gmur, Nicholas F.; Evans, Lance S.; Cunningham, Elizabeth A.

    These experiments were designed to provide information on the rates of aerosol deposition, mode of entry, and effects of deposition of submicrometer ammonium sulfate aerosols on foliage of Phaseolus vulgaris L. A deposition velocity of 3.2 × 10 3cms-1 was constant during 3-week exposures of plants to aerosol concentrations of 26mg m -3 (i.e. about two orders of magnitude above ambient episode concentrations). Mean deposition rate on foliage was 4.1 × 10 -11 μg cm -2s -1. Visible injury symptoms included leaf chlorosis, necrosis and loss of turgor. Chlorosis was most frequent near leaf margins causing epinasty and near major veins. Internal injury occurred initially in spongy mesophyll cells. Eventually abaxial epidermal and palisade parenchyma cells were injured. These results suggest that submicrometer aerosols enter abaxial stomata and affect more internal cells before affecting leaf surface cells. Exposure to aerosols decreased both abaxial and adaxial leaf resistances markedly. Although visible injury to foliage occurred, no changes in dry mass of roots and shoots or leaf area occurred. These results suggest that for the plant developmental stage studied, while leaf resistances decreased and cellular injury occurred in foliage, these factors were not significantly related to plant growth and development.

  7. Effects of ammonium sulfate aerosols on vegetation--II. Mode of entry and responses of vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Gmur, N.F. (Brookhaven National Lab., Upton, NY); Evans, L.S.; Cunningham, E.A.

    1983-01-01

    These experiments were designed to provide information on the rates of aerosol deposition, mode of entry, and effects of deposition of submicrometer ammonium sulfate aerosols on foliage of Phaseolus vulgaris L. A deposition velocity of 3.2 x 10/sup -3/ cm s/sup -1/ was constant during 3-week exposures of plants to aerosol concentrations of 26mg m/sup -3/ (i.e., about two orders of magnitude above ambient episode concentrations). Mean deposition rate on foliage was 4.1 x 10/sup -11/ ..mu..g cm/sup -2/ s/sup -1/. Visible injury symptoms included leaf chlorosis, necrosis, and loss of turgor. Chlorosis was most frequent near leaf margins causing epinasty and near major veins. Internal injury occurred initially in spongy mesophyll cells. Eventually abaxial epidermal and palisade parenchyma cells were injured. These results suggest that submicrometer aerosols enter abaxial stomata and affect more internal cells before affecting leaf surface cells. Exposure to aerosols decreased both abaxial and adaxial leaf resistances markedly. Although visible injury to foliage occurred, no change in dry mass of roots and shoots or leaf area occurred. These results suggest that for the plant developmental stage studied, while leaf resistances decreased and cellular injury occurred in foliage, these factors were not significantly related to plant growth and development.

  8. Fly Ash and Composted Bio solids as a Source of Fe for Hybrid Poplar: A Greenhouse Study

    International Nuclear Information System (INIS)

    Soils of northwest New Mexico have an elevated ph and CaCo3 content that reduces Fe solubility, causes chlorosis, and reduces crop yields. Could bio solids and fly ash, enriched with Fe, provide safe alternatives to expensive Fe EDDHA (sodium ferric ethylenediamine di-(o-hydroxyphenyl-acetate)) fertilizers applied to Populus hybrid plots? Hybrid OP-367 was cultivated on a Doak sandy loam soil amended with composted bio solids or fly ash at three agricultural rates. Fly ash and Fe EDDHA treatments received urea ammonium nitrate (UAN), bio solids, enriched with N, did not. Both amendments improved soil and plant Fe. Heavy metals were below EPA regulations, but high B levels were noted in leaves of trees treated at the highest fly ash rate. ph increased in fly ash soil while salinity increased in bio solids-treated soil. Chlorosis rankings improved in poplars amended with both byproducts, although composted bio solids offered the most potential at improving Fe/tree growth cheaply without the need for synthetic inputs.

  9. Differential gene expression in Xylella fastidiosa 9a5c during co-cultivation with the endophytic bacterium Methylobacterium mesophilicum SR1.6/6.

    Science.gov (United States)

    Dourado, Manuella Nóbrega; Santos, Daiene Souza; Nunes, Luiz Roberto; Costa de Oliveira, Regina Lúcia Batista da; de Oliveira, Marcus Vinicius; Araújo, Welington Luiz

    2015-12-01

    Xylella fastidiosa, the causal agent of citrus variegated chlorosis (CVC), colonizes plant xylem, reducing sap flow, and inducing internerval chlorosis, leaf size reduction, necrosis, and harder and smaller fruits. This bacterium may be transmitted from plant to plant by sharpshooter insects, including Bucephalogonia xanthopis. The citrus endophytic bacterium Methylobacterium mesophilicum SR1.6/6 colonizes citrus xylem and previous studies showed that this strain is also transferred from plant to plant by B. xanthopis (Insecta), suggesting that this endophytic bacterium may interact with X. fastidiosa in planta and inside the insect vector during co-transmission by the same insect vector. To better understand the X. fastidiosa behavior in the presence of M. mesophilicum, we evaluated the X. fastidiosa transcriptional profile during in vitro interaction with M. mesophilicum SR1.6/6. The results showed that during co-cultivation, X. fastidiosa down-regulated genes related to growth and up-regulated genes related to energy production, stress, transport, and motility, suggesting the existence of a specific adaptive response to the presence of M. mesophilicum in the culture medium. PMID:26218710

  10. The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

    Science.gov (United States)

    Bao, Aili; Zhao, Zhuqing; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2015-06-04

    Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

  11. Main viruses in sweet cherry plantations of Central-Western Spain

    Directory of Open Access Journals (Sweden)

    Rodrigo Pérez Sánchez

    2015-02-01

    Full Text Available Sweet cherry trees (Prunus avium L. are susceptible to a range of diseases, but there have been no studies to date about the viral infection of sweet cherry trees in Spain. To determine the phytosanitary status of Spanish sweet cherry plantations, the incidence and leaf symptoms induced by Prune dwarf (PDV, Prunus necrotic ringspot (PNRSV and Apple chlorotic leaf spot (ACLSV viruses were investigated during 2009. Young leaf samples were taken from 350 sweet cherry trees, corresponding to 17 cultivars, and were analysed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA. To associate the leaf symptoms with the virus, 50 mature leaves from each infected tree were visually inspected during the summer. The ELISA results revealed that 72 % of sweet cherry trees were infected by at least one of the viruses. PDV occurred in all sampled cultivars and presented the highest infection rate, followed by ACLSV and PNRSV. A high number of trees showed asymptomatic, in both single and mixed infections. The leaf symptoms associated with the viruses involved generalized chlorosis around the midvein (PDV, chlorotic and dark brown necrotic ringspots on both secondary veins and intervein regions (PNRSV, chlorotic and reddish necrotic ringspots (ACLSV and generalized interveinal chlorosis (PDV-PNRSV.

  12. Phytotoxic Effects of Gliricidia sepium Prunings on Maize Germination and Growth

    International Nuclear Information System (INIS)

    Gliricidia sepium prunings are known to have both positive and negative effects on agrocrops. In this study, it's phytotoxic effects on maize seedlings were evaluated under both laboratory and field conditions. In the laboratory, a leachate of dry Gliricidia prunings (leaves) was prepared and used to irrigate maize seeds during germination and early growth. Three levels of leachate concentrations (25%, 50% and 100%) and control (distilled water) were used. Germination percentage and fresh weights of radicles and shoots were taken 10 Days After Planting (10 DAP). In the field, dry Gliricidia prunings were applied on experimental plots (0.5mx0.5m) as mulch at the rate of 10 tons ha-1 at 0, 1, 2 and 3 weeks before planting the maize seeds and a control where no mulch was added. Each plot was planted with 60 maize seeds and artificially irrigated. Germination percentage, leaf chlorosis and seedling biomass at 10 and 20 DAP were measure for each treatment. In the laboratory, Gliricidia leachate slightly reduced germination and depressed radicle and shoot growths of maize seedlings significantly (ANOVA: P,0.05). In the field there was no significant reduction in maize seed germination and growth due to addition of mulch. However, the lowest germination and biomass and the highest leaf chlorosis were recorded in the plots where mulch was added 10 weeks before planting the maize seeds

  13. Weed Control and Grain Sorghum (Sorghum bicolor Tolerance to Pyrasulfotole plus Bromoxynil

    Directory of Open Access Journals (Sweden)

    Dan D. Fromme

    2012-01-01

    Full Text Available Field studies were conducted during the 2008 and 2009 growing seasons at five locations in the Texas grain sorghum producing regions to evaluate pyrasulfotole plus bromoxynil combinations for weed control and grain sorghum response. All pyrasulfotole plus bromoxynil combinations controlled Amaranthus palmeri, Cucumis melo, and Proboscidea louisianica at least 94% while control of Urochloa texana was never better than 69%. Pyrasulfotole plus bromoxynil combinations did result in early season chlorosis and stunting; however, by the end of the growing season no visual injury or stunting differences were noted when compared to the untreated check. Early season grain sorghum chlorosis and stunting with pyrasulfotole plus bromoxynil combinations did not affect grain sorghum yields with the exception of pyrasulfotole at 0.03 kg ai/ha plus bromoxynil at 0.26 kg ai/ha plus atrazine at 0.58 kg ai/ha applied early postemergence followed by pyrasulfotole plus bromoxynil applied mid-postemergence which reduced yield at one of two locations in 2008. Grain sorghum yield increased following all pyrasulfotole plus bromoxynil treatments compared to the untreated check in 2009.

  14. Calcium Supplementation Improves Na+/K+ Ratio, Antioxidant Defense and Glyoxalase Systems in Salt-Stressed Rice Seedlings

    Science.gov (United States)

    Rahman, Anisur; Nahar, Kamrun; Hasanuzzaman, Mirza; Fujita, Masayuki

    2016-01-01

    The present study investigates the regulatory role of exogenous calcium (Ca) in developing salt stress tolerance in rice seedlings. Hydroponically grown 13-day-old rice (Oryza sativa L. cv. BRRI dhan47) seedlings were exposed to 200 mM NaCl alone and combined with 2 mM CaCl2 and 2 mM ethylene glycol tetraacetic acid (EGTA, a Ca scavenger) for 3 days. The salt stress caused growth inhibition, chlorosis and water shortage in the rice seedlings. The salt-induced stress disrupted ion homeostasis through Na+ influx and K+ efflux, and decreased other mineral nutrient uptake. Salt stress caused oxidative stress in seedlings through lipid peroxidation, loss of plasma membrane integrity, higher reactive oxygen species (ROS) production and methylglyoxal (MG) formation. The salt-stressed seedlings supplemented with exogenous Ca recovered from water loss, chlorosis and growth inhibition. Calcium supplementation in the salt-stressed rice seedlings improved ion homeostasis by inhibition of Na+ influx and K+ leakage. Exogenous Ca also improved ROS and MG detoxification by improving the antioxidant defense and glyoxalase systems, respectively. On the other hand, applying EGTA along with salt and Ca again negatively affected the seedlings as EGTA negated Ca activity. It confirms that, the positive responses in salt-stressed rice seedlings to exogenous Ca were for Ca mediated improvement of ion homeostasis, antioxidant defense and glyoxalase system. PMID:27242816

  15. Phytotoxic effects of fungicides, insecticides and nonpesticidal components on pepper depending on water quality

    Directory of Open Access Journals (Sweden)

    Slavica Vuković

    2014-06-01

    Full Text Available Modern agriculture relies on simultaneous application of fungicides, insecticides, fertilizers and adjuvants. The selection of compounds for tank-mixes has been rarely studied and it presents a risk in the application of pesticides but the quality of water should also be considered. The aim of this study was to assess the phytotoxic effects of several fungicides, insecticides, a complex fertilizer, an adjuvant and their mixtures on pepper (Capsicum annuum L. as a test plant, depending on water quality. The effects of the pesticides: azoxystrobin (Quadris, 0.75 l/ha, mancozeb (Dithane M-70, 2.5 kg/ha, thiamethoxam (Actara 25-WG, 0.07 kg/ha and cypermethrin (Cipkord EC-20, 0.3 l/ha, a complex fertilizer (Mortonijc plus /hereinafter: M+/ 3kg/ha, an adjuvant (Sillwet 77-L, 0.1 l/ha and their mixtures, were assessed depending on the quality of water (well water – slightly alkaline, very hard and with high nitrite content; tap water – neutral and slightly hard; surface water – alkaline, slightly hard and with high content of nitrite and ammonia using a puncture method. The effects were assessed after seven days by measuring the diameter of chlorosis and/or necrosis around puncture sites, and were expressed in mm2. The significance of differences between treatments was analyzed using a one-way ANOVA (LSD 0.05 %. In the slightly alkaline and very hard well water, all spray liquids containing Dithane M-70 caused a significant increase in leaf chlorosis area (from 6.0 to 25.2 mm2, compared to the control and other treatments. In the neutral and slightly hard tap water, all spray liquids containing Dithane M-70 caused a significant increase in leaf chlorosis (5.3 to 7.9 mm2 compared to the control and the other spray liquids, although its phytotoxicity in that water was at a lower level than it was in well water. However, in the weakly alkaline and slightly hard surface water from the river Sava, Dithane M–70, Dithane M-70 + Actara WG-25, Dithane M

  16. Iron and ferritin accumulate in separate cellular locations in Phaseolus seeds

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Przybylowicz, Wojciech J; Urbanski, Dorian Fabian;

    2010-01-01

    Background Iron is an important micronutrient for all living organisms. Almost 25% of the world's population is affected by iron deficiency, a leading cause of anemia. In plants, iron deficiency leads to chlorosis and reduced yield. Both animals and plants may suffer from iron deficiency when...... their diet or environment lacks bioavailable iron. A sustainable way to reduce iron malnutrition in humans is to develop staple crops with increased content of bioavailable iron. Knowledge of where and how iron accumulates in seeds of crop plants will increase the understanding of plant iron metabolism...... and will assist in the production of staples with increased bioavailable iron. Results Here we reveal the distribution of iron in seeds of three Phaseolus species including thirteen genotypes of P. vulgaris, P. coccineus, and P. lunatus. We showed that high concentrations of iron accumulate in cells surrounding...

  17. Complete genome sequence of yacon necrotic mottle virus, a novel putative member of the genus Badnavirus.

    Science.gov (United States)

    Lee, Ye-Ji; Kwak, Hae-Ryun; Lee, Young-Kee; Kim, Mi-Kyeong; Choi, Hong-Soo; Seo, Jang-Kyun

    2015-04-01

    The complete genome sequence of a previously undescribed virus isolated from a yacon plant exhibiting necrotic mottle, chlorosis, stunting, and leaf malformation symptoms in Gyeongju, Korea, was determined. The genome of this virus consists of one circular double-stranded DNA of 7661 bp in size. The genome contained four open reading frames (ORFs 1 to 4) on the plus strand that potentially encode proteins of 26, 32, 234, and 25 kDa. Protein BLAST analysis showed that ORF3, which is the largest ORF, has 45 % amino acid sequence identity (with 89 % coverage) to the ORF3 of fig badnavirus 1 (FBV-1), a recently identified badnavirus. Phylogenetic analysis provided further evidence that the virus identified in this study is probably a member of a new species in the genus Badnavirus. The name yacon necrotic mottle virus (YNMoV) is proposed for this new virus.

  18. Steel Slag as an Iron Fertilizer for Corn Growth and Soil Improvement in a Pot Experiment

    Institute of Scientific and Technical Information of China (English)

    WANG Xian; CAI Qing-Sheng

    2006-01-01

    The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1)of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.

  19. Complete genome sequence of yacon necrotic mottle virus, a novel putative member of the genus Badnavirus.

    Science.gov (United States)

    Lee, Ye-Ji; Kwak, Hae-Ryun; Lee, Young-Kee; Kim, Mi-Kyeong; Choi, Hong-Soo; Seo, Jang-Kyun

    2015-04-01

    The complete genome sequence of a previously undescribed virus isolated from a yacon plant exhibiting necrotic mottle, chlorosis, stunting, and leaf malformation symptoms in Gyeongju, Korea, was determined. The genome of this virus consists of one circular double-stranded DNA of 7661 bp in size. The genome contained four open reading frames (ORFs 1 to 4) on the plus strand that potentially encode proteins of 26, 32, 234, and 25 kDa. Protein BLAST analysis showed that ORF3, which is the largest ORF, has 45 % amino acid sequence identity (with 89 % coverage) to the ORF3 of fig badnavirus 1 (FBV-1), a recently identified badnavirus. Phylogenetic analysis provided further evidence that the virus identified in this study is probably a member of a new species in the genus Badnavirus. The name yacon necrotic mottle virus (YNMoV) is proposed for this new virus. PMID:25643816

  20. Exogenous Nitric Oxide Alleviated the Inhibition of Photosynthesis and Antioxidant Enzyme Activities in Iron-Deficient Chinese Cabbage(Brassica chinensis L.)

    Institute of Scientific and Technical Information of China (English)

    DING Fei; WANG Xiu-feng; SHI Qing-hua; WANG Mei-ling; YANG Feng-juan; GAO Qing-hai

    2008-01-01

    The effects of exogenous nitric oxide(NO)on plant growth,chlorophyll contents,photosynthetic and chlorophyll fluorescence parameters as well as lipid peroxidation and activities of antioxidant enzymes were investigated in Chinese cabbage plants exposed to iron(Fe)deficiency.Iron deficiency led to serious chlorosis in Chinese cabbage leaves,and resulted in significant decrease in plant growth,photosynthetic pigments,net photosynthetic rate,Fv/Fm,ΦPsⅡand activities of antioxidant enzymes,and increase in lipid peroxidation.While treatment with SNP,a NO donor,it could revert the iron deficiency symptoms,increased photosynthetic rate as well as activities of antioxidant enzymes,and protected membrane from lipid peroxidation,as a result,the growth inhibition of Chinese cabbage by Fe deficiency was alleviated.

  1. Long-chain acyl-homoserine lactones from Methylobacterium mesophilicum: synthesis and absolute configuration.

    Science.gov (United States)

    Pomini, Armando M; Cruz, Pedro L R; Gai, Cláudia; Araújo, Welington L; Marsaioli, Anita J

    2009-12-01

    The acyl-homoserine lactones (acyl-HSLs) produced by Methylobacterium mesophilicum isolated from orange trees infected with the citrus variegated chlorosis (CVC) disease have been studied, revealing the occurrence of six long-chain acyl-HSLs, i.e., the saturated homologues (S)-N-dodecanoyl (1) and (S)-N-tetradecanoyl-HSL (5), the uncommon odd-chain N-tridecanoyl-HSL (3), the new natural product (S)-N-(2E)-dodecenoyl-HSL (2), and the rare unsaturated homologues (S)-N-(7Z)-tetradecenoyl (4) and (S)-N-(2E,7Z)-tetradecadienyl-HSL (6). The absolute configurations of all HSLs were determined as 3S. Compounds 2 and 6 were synthesized for the first time. Antimicrobial assays with synthetic acyl-HSLs against Gram-positive bacterial endophytes co-isolated with M. mesophilicum from CVC-infected trees revealed low or no antibacterial activity. PMID:19919062

  2. Fastidian gum: the Xylella fastidiosa exopolysaccharide possibly involved in bacterial pathogenicity.

    Science.gov (United States)

    da Silva, F R; Vettore, A L; Kemper, E L; Leite, A; Arruda, P

    2001-09-25

    The Gram-negative bacterium Xylella fastidiosa was the first plant pathogen to be completely sequenced. This species causes several economically important plant diseases, including citrus variegated chlorosis (CVC). Analysis of the genomic sequence of X. fastidiosa revealed a 12 kb DNA fragment containing an operon closely related to the gum operon of Xanthomonas campestris. The presence of all genes involved in the synthesis of sugar precursors, existence of exopolysaccharide (EPS) production regulators in the genome, and the absence of three of the X. campestris gum genes suggested that X. fastidiosa is able to synthesize an EPS different from that of xanthan gum. This novel EPS probably consists of polymerized tetrasaccharide repeating units assembled by the sequential addition of glucose-1-phosphate, glucose, mannose and glucuronic acid on a polyprenol phosphate carrier. PMID:11583843

  3. [Changes in the biochemical composition, structure, and function of pea leaf chloroplasts in iron deficiency and root anoxia].

    Science.gov (United States)

    Ladygin, V G

    2004-01-01

    A combined effect of iron deficiency and root anoxia on the biochemical composition, function, and structure of pea leaf chloroplasts was studied. It was found that the chlorosis of apical leaves in response to iron deficiency was determined by the reduction of light-harvesting complexes I and II. Under root anoxia, complexes of the reaction centers of photosystems I and II degraded first. Weak activity was preserved even in yellow and white leaves under the effect of both factors. The ultrastructure of leaf chloroplasts gradually degraded. Initially, intergranal thylakoid sites were reduced, and the longitudinal orientation of grana was disturbed. However, yellow and white leaves still retained small thylakoids and grana. It is concluded that the degrading effects of iron deficiency and root anoxia on the complex composition and leaf chloroplast structure and function are additive because of their autonomous mechanisms. PMID:15553792

  4. Molecular mapping for seedling cold tolerance QTLs in rice

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The quantitative trait loci (QTLs) for cold tolerance relative characters were identified with microsatellitemarkers. Ten QTLs located on chromosome 1, 3, 4, 5, 6, 8, 9, 11(two)and 12 were detected for seedling height atdifferent low temperature. Only 2 of these were detected at the same locus at four environments, 1 was significant atthree environments, 6 were significant at two environments and 1 was significant at one environment. Seven QTLslocated on chromosome 1(two), 2(two),5,6, 8 were found for low temperature chlorosis resistance and five QTLslocated on chromosome 3, 4, 7, 8, 11 resistant to chilling injury. The amount of variation explained by individual QTLranged from 4.85% to 49.34%. There was no linkage relationship among the three characters, which indicates seedlingcold tolerance is a complex character and is controlled by different QTLs.

  5. IN - VITRO AND GREENHOUSE EVALUATION OF PHYTOPATHOGENIC POTENTIAL OF FUNGAL ISOLATES Alternaria tenuissima IN IRAN

    Directory of Open Access Journals (Sweden)

    Mirkarimi HR

    2013-09-01

    Full Text Available Early blight of solanaceae is the most common reported disease in Iran. The disease caused by Alternaria species.Various isolates of Alternaria tenuissima were collected from various locations of the country. The collected Isolates were tested against tomato (Lycopersicon lycopersicumL. crops in fields of Khansar Esfehan and National Plant Gene Bank of Iran. For d etermining the pathogenicity, these strains were tested against the genetic samples of Agria (susceptible, Delta (resistant control and Cosmos. Symptoms were recorded in both in vitro and greenhouse conditions. Under in vitro condition genetic samples of Agria and Cosmos shows the pathogenic symptoms second day while the Delta is showing symptoms fifth day after inoculation. The reported symptoms were necrosis, chlorosis and damping. Under greenhouse evaluation, the symptoms became apparent in the genetic Agria fourth day, while in Cosmos at the eighth day and in Delta fourteenth day after inoculation. Finally, morphology and pathogenicity tests, asserted the isolation of pathogenic A. tenuissima.

  6. Screening for disease resistance in barley cultivars against Bipolaris sorokiniana using callus culture method.

    Science.gov (United States)

    Chand, Ramesh; Sen, Devyani; Prasad, K D; Singh, A K; Bashyal, B M; Prasad, L C; Joshi, A K

    2008-04-01

    Screening for resistant barley genotypes in response to fungal toxin of Bipolaris sorokiniana was assessed on standing barley plants as well as in selected callus lines of the same. For the standing lines tested, those manifesting chlorosis in response to toxin infiltration showed a significantly slower disease progress as compared to the necrotic lines. Also, necrosis in the callus tissues of the susceptible cultivar in MS medium supplemented with different concentrations of the crude toxin was significantly higher than in the callus tissues of the chlorotic lines studied. Similar host response to the toxin in in vitro and field situations open up the possibility of screening barley cultivars for resistance to spot blotch using callus culture as against classical methods of screening in order to increase accuracy and save time and space.

  7. Índices agronômicos do meloeiro associados à dose adequada de nitrogênio, em ambiente protegido e no campo Muskmelon plant agronomical indice values associated with adequadenitrogen fertilizer rate, in unheated greenhouse and field

    Directory of Open Access Journals (Sweden)

    Evando Luiz Coelho

    2005-10-01

    conditions. Two experiments, in unheated greenhouse and field conditions, were carried out with similar procedures. Each experiment consisted of four randomized blocks containing five treatments or five nitrogen rates (0, 75, 150, 300, and 450 kg ha-1 of N, applied as urea. Part of the fertilizer was placed in furrows (30%, before seedling transplantation, and the remaining 70% were trickle-applied through part of the plant cycle. Initially, 14 days after transplantation, plant chlorosis intensity was evaluated by scores from 0 (no chlorosis to 5 (leaves completely chlorotics. At 25 and 53 days after transplantation, at first and second fruit setting, FLA and FLW were determined. At both experiments, chlorosis intensity decreased, FLA and FLW increased with increasing N rates. Chlorosis intensity values associated with MFY were 0.22 and 1.11 at greenhouse and field, respectively. In the greenhouse, at first and second sampling dates, FLA values associated with MFY were 107 and 72 cm² and FLW values were 0.36 and 0.26 g, respectively. In the field, the corresponding values were 89 and 69 cm² and 0.39 and 0.30 g, respectively. These are proposed melon plant index values indicators of the added N fertilizer rate adequacy.

  8. Proton activation studies of changes in mineral composition of eucalyptus obliqua due to phytophthora cinnamomi

    International Nuclear Information System (INIS)

    As part of a study of disease caused by Phytophthora cinnamomi in native vegetation, the mineral composition of diseased plants was compared with those free from disease, but grown under the same conditions. Young plants of Eucalyptus obliqua, three years old and with well-formed lignotubers, were selected (a) diseased plant from soil containing a high concentration of P. cinnamomi, and (b) unaffected plant from an adjacent area where the soil was free from this pathogen. The plants were ashed and their mineral composition was compared by activation analysis using proton beams from the Melbourne University Cyclotron. Results showed a 70% reduction in iron and 41% in titanium from diseased plants compared with disease-free plants. The reduction in iron is associated with severe chlorosis which occurs as a primary symptom in most plants attacked by this pathogen

  9. [Bacterial diseases of rape].

    Science.gov (United States)

    Zakharova, O M; Mel'nychuk, M D; Dankevych, L A; Patyka, V P

    2012-01-01

    Bacterial destruction of the culture was described and its agents identified in the spring and winter rape crops. Typical symptoms are the following: browning of stem tissue and its mucilagization, chlorosis of leaves, yellowing and beginning of soft rot in the place of leaf stalks affixion to stems, loss of pigmentation (violet). Pathogenic properties of the collection strains and morphological, cultural, physiological, and biochemical properties of the agents of rape's bacterial diseases isolated by the authors have been investigated. It was found that all the isolates selected by the authors are highly or moderately aggressive towards different varieties of rape. According to the complex of phenotypic properties 44% of the total number of isolates selected by the authors are related to representatives of the genus Pseudomonas, 37% - to Xanthomonas and 19% - to Pectobacterium. PMID:23293826

  10. Effects of simulated acid rain on the morphology, phenology and dry biomass of a local variety of maize (Suwan-1) in Southwestern Nigeria.

    Science.gov (United States)

    Macaulay, Babajide Milton; Enahoro, Gloria Ebarunosen

    2015-10-01

    Effects of acid rain on the morphology, phenology and dry biomass of maize (Suwan-1 variety) were investigated. The maize seedlings were subjected to different pH treatments (1.0, 2.0, 3.0, 4.0, 5.0 and 6.0) of simulated acid rain (SAR) with pH 7.0 as the control for a period of 90 days. The common morphological defects due to SAR application were necrosis and chlorosis. It was observed that necrosis increased in severity as the acidity increased whilst chlorosis was dominant as the acidity decreased. SAR encouraged rapid floral and cob growth but with the consequence of poor floral and cob development in pH 1.0 to 3.0 treatments. The result for the dry biomass indicates that pH treatments 2.0 to 7.0 for total plant biomass were not significantly different (P > 0.05) from one another, but were all significantly higher (P acid rain but with pronounced morphological and phenological defects which, however, have the capacity to reduce drastically the market value of the crop. Therefore, it may be concluded that Suwan-1 tolerated acid rain in terms of the parameters studied at pH 4.0 to 7.0 which makes it a suitable crop in acid rain-stricken climes. This research could also serve as a good reference for further SAR studies on maize or other important cereals. PMID:26362878

  11. Arbuscular-mycorrhizal networks inhibit Eucalyptus tetrodonta seedlings in rain forest soil microcosms.

    Directory of Open Access Journals (Sweden)

    David P Janos

    Full Text Available Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks-previously unrecognized as contributors to the ashbed effect-probably help to maintain the rain forest-savanna boundary.

  12. Epidemiology and genetic diversity of criniviruses associated with tomato yellows disease in Greece.

    Science.gov (United States)

    Orfanidou, C G; Dimitriou, C; Papayiannis, L C; Maliogka, V I; Katis, N I

    2014-06-24

    Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are two whitefly transmitted viruses which are classified in the genus Crinivirus of the family Closteroviridae. Both induce similar yellowing symptoms in tomato and are responsible for severe economic losses. ToCV is transmitted by Bemisia tabaci Gennadious, Trialeurodes vaporariorum Westwood and Trialeurodes abutilonea Haldeman, whereas TICV is transmitted only by T. vaporariorum. An extensive study was conducted during 2009-2012 in order to identify the virus species involved in tomato yellowing disease in Greece. Samples from tomato, other crops and weeds belonging to 44 species from 26 families were collected and analyzed using molecular methods. In addition, adult whiteflies were collected and analyzed using morphological characters and DNA markers. Results showed that TICV prevailed in tomato crops (62.5%), while ToCV incidence was lower (20.5%) and confined in southern Greece. ToCV was also detected in lettuce plants showing mild yellowing symptoms for the first time in Greece. Approximately 13% of the tested weeds were found to be infected, with TICV being the predominant virus with an incidence of 10.8%, whereas ToCV was detected only in 2.2% of the analyzed samples. These results indicate that the host range of TICV and ToCV in Greece is far more extensive than previously believed. T. vaporariorum was the most widespread whitefly species in Greece (80%), followed by B. tabaci (biotypes B and Q) (20%). Sequence analysis of the CP and CPm genes from Greek tomato and weed isolates of ToCV and TICV showed that even though both viruses have very wide host ranges their populations show very low molecular divergence.

  13. Nitric Oxide Improves Internal Iron Availability in Plants1

    Science.gov (United States)

    Graziano, Magdalena; Beligni, María Verónica; Lamattina, Lorenzo

    2002-01-01

    Iron deficiency impairs chlorophyll biosynthesis and chloroplast development. In leaves, most of the iron must cross several biological membranes to reach the chloroplast. The components involved in the complex internal iron transport are largely unknown. Nitric oxide (NO), a bioactive free radical, can react with transition metals to form metal-nitrosyl complexes. Sodium nitroprusside, an NO donor, completely prevented leaf interveinal chlorosis in maize (Zea mays) plants growing with an iron concentration as low as 10 μm Fe-EDTA in the nutrient solution. S-Nitroso-N-acetylpenicillamine, another NO donor, as well as gaseous NO supply in a translucent chamber were also able to revert the iron deficiency symptoms. A specific NO scavenger, 2-(4-carboxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, blocked the effect of the NO donors. The effect of NO treatment on the photosynthetic apparatus of iron-deficient plants was also studied. Electron micrographs of mesophyll cells from iron-deficient maize plants revealed plastids with few photosynthetic lamellae and rudimentary grana. In contrast, in NO-treated maize plants, mesophyll chloroplast appeared completely developed. NO treatment did not increase iron content in plant organs, when expressed in a fresh matter basis, suggesting that root iron uptake was not enhanced. NO scavengers 2-(4-carboxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and methylene blue promoted interveinal chlorosis in iron-replete maize plants (growing in 250 μm Fe-EDTA). Even though results support a role for endogenous NO in iron nutrition, experiments did not establish an essential role. NO was also able to revert the chlorotic phenotype of the iron-inefficient maize mutants yellow stripe1 and yellow stripe3, both impaired in the iron uptake mechanisms. All together, these results support a biological action of NO on the availability and/or delivery of metabolically active iron within the plant. PMID:12481068

  14. Bacterial Wilt and Boron Deficiency Stress: A New Disorder in Eucalypt Plantations in South China

    Institute of Scientific and Technical Information of China (English)

    DELL Bernard; XU Daping

    2006-01-01

    This paper reports on a new disorder that first appeared in eucalypt plantations in south China in 2003. The plantations were destructively sampled near Leizhou, Yanxi, Kaiping and Gaoyao in September to December 2003. Whilst some 5% of 0.5 to 1.5 year-old Eucalyptus urophylla trees declined rapidly and exhibited symptoms of wilting, the majority of the affected trees declined slowly and exhibited two foliar symptoms. Young leaves initially developed an interveinal chlorosis extending from the leaf margin inwards to the midrib. Most leaves then developed pockets of necrotic tissue that became bleached but typically had brown margins. The former symptoms have been recognised as being caused by limited boron supply in soil, but the latter symptoms have not been previously observed in eucalypts in China. Inorganic analysis showed that the leaves with the latter symptoms had deficient B concentrations whereas the leaves from healthy trees had adequate B concentrations. Bacterial wilt, Ralstonia solanacearum, was present at all sites where foliar symptoms and tree death were present. The root system of all trees with foliar chlorosis and necrosis had signs of infection in some roots and attrition of lateral roots. The trunk and branches of the recently died trees and the trees with advanced leaf drop had discoloured xylem, which on cutting, oozed bacterial slime. Possible relationships between root damage caused by abiotic (e.g. typhoons, root damage from hand weeding) and biotic factors and reduced B uptake are discussed. Recommendations are made for reducing bacterial wilt disease and improving B management in fast-growing short-rotation eucalypt plantations.

  15. Exogenous auxin alleviates cadmium toxicity in Arabidopsis thaliana by stimulating synthesis of hemicellulose 1 and increasing the cadmium fixation capacity of root cell walls

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiao Fang [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Wang, Zhi Wei [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Dong, Fang; Lei, Gui Jie [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Shi, Yuan Zhi [The Key Laboratory of Tea Chemical Engineering, Ministry of Agriculture, Yunqi Road 1, Hangzhou 310008 (China); Li, Gui Xin, E-mail: guixinli@zju.edu.cn [College of Agronomy and Biotechnology, Zhejiang University, Hangzhou 310058 (China); Zheng, Shao Jian [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China)

    2013-12-15

    Highlights: • Cd reduces endogenous auxin levels in Arabidopsis. • Exogenous applied auxin NAA increases Cd accumulation in the roots but decreases in the shoots. • NAA increases cell wall hemicellulose 1 content. • Hemicellulose 1 retains Cd and makes it difficult to be translocated to shoots. • NAA rescues Cd-induced chlorosis. -- Abstract: Auxin is involved in not only plant physiological and developmental processes but also plant responses to abiotic stresses. In this study, cadmium (Cd{sup 2+}) stress decreased the endogenous auxin level, whereas exogenous auxin (α-naphthaleneacetic acid, NAA, a permeable auxin analog) reduced shoot Cd{sup 2+} concentration and rescued Cd{sup 2+}-induced chlorosis in Arabidopsis thaliana. Under Cd{sup 2+} stress conditions, NAA increased Cd{sup 2+} retention in the roots and most Cd{sup 2+} in the roots was fixed in hemicellulose 1 of the cell wall. NAA treatment did not affect pectin content and its binding capacity for Cd{sup 2+}, whereas it significantly increased the content of hemicellulose 1 and the amount of Cd{sup 2+} retained in it. There were highly significant correlations between Cd{sup 2+} concentrations in the root, cell wall and hemicellulose 1 when the plants were subjected to Cd{sup 2+} or NAA + Cd{sup 2+} treatment for 1 to 7 d, suggesting that the increase in hemicellulose 1 contributes greatly to the fixation of Cd{sup 2+} in the cell wall. Taken together, these results demonstrate that auxin-induced alleviation of Cd{sup 2+} toxicity in Arabidopsis is mediated through increasing hemicellulose 1 content and Cd{sup 2+} fixation in the root, thus reducing the translocation of Cd{sup 2+} from roots to shoots.

  16. Suppressing Farnesyl Diphosphate Synthase Alters Chloroplast Development and Triggers Sterol-Dependent Induction of Jasmonate- and Fe-Related Responses.

    Science.gov (United States)

    Manzano, David; Andrade, Paola; Caudepón, Daniel; Altabella, Teresa; Arró, Montserrat; Ferrer, Albert

    2016-09-01

    Farnesyl diphosphate synthase (FPS) catalyzes the synthesis of farnesyl diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate. Arabidopsis (Arabidopsis thaliana) contains two genes (FPS1 and FPS2) encoding FPS. Single fps1 and fps2 knockout mutants are phenotypically indistinguishable from wild-type plants, while fps1/fps2 double mutants are embryo lethal. To assess the effect of FPS down-regulation at postembryonic developmental stages, we generated Arabidopsis conditional knockdown mutants expressing artificial microRNAs devised to simultaneously silence both FPS genes. Induction of silencing from germination rapidly caused chlorosis and a strong developmental phenotype that led to seedling lethality. However, silencing of FPS after seed germination resulted in a slight developmental delay only, although leaves and cotyledons continued to show chlorosis and altered chloroplasts. Metabolomic analyses also revealed drastic changes in the profile of sterols, ubiquinones, and plastidial isoprenoids. RNA sequencing and reverse transcription-quantitative polymerase chain reaction transcriptomic analysis showed that a reduction in FPS activity levels triggers the misregulation of genes involved in biotic and abiotic stress responses, the most prominent one being the rapid induction of a set of genes related to the jasmonic acid pathway. Down-regulation of FPS also triggered an iron-deficiency transcriptional response that is consistent with the iron-deficient phenotype observed in FPS-silenced plants. The specific inhibition of the sterol biosynthesis pathway by chemical and genetic blockage mimicked these transcriptional responses, indicating that sterol depletion is the primary cause of the observed alterations. Our results highlight the importance of sterol homeostasis for normal chloroplast development and function and reveal important clues about how isoprenoid and sterol metabolism is integrated within plant physiology and development. PMID

  17. Suppressing Farnesyl Diphosphate Synthase Alters Chloroplast Development and Triggers Sterol-Dependent Induction of Jasmonate- and Fe-Related Responses1[OPEN

    Science.gov (United States)

    Andrade, Paola; Caudepón, Daniel; Arró, Montserrat

    2016-01-01

    Farnesyl diphosphate synthase (FPS) catalyzes the synthesis of farnesyl diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate. Arabidopsis (Arabidopsis thaliana) contains two genes (FPS1 and FPS2) encoding FPS. Single fps1 and fps2 knockout mutants are phenotypically indistinguishable from wild-type plants, while fps1/fps2 double mutants are embryo lethal. To assess the effect of FPS down-regulation at postembryonic developmental stages, we generated Arabidopsis conditional knockdown mutants expressing artificial microRNAs devised to simultaneously silence both FPS genes. Induction of silencing from germination rapidly caused chlorosis and a strong developmental phenotype that led to seedling lethality. However, silencing of FPS after seed germination resulted in a slight developmental delay only, although leaves and cotyledons continued to show chlorosis and altered chloroplasts. Metabolomic analyses also revealed drastic changes in the profile of sterols, ubiquinones, and plastidial isoprenoids. RNA sequencing and reverse transcription-quantitative polymerase chain reaction transcriptomic analysis showed that a reduction in FPS activity levels triggers the misregulation of genes involved in biotic and abiotic stress responses, the most prominent one being the rapid induction of a set of genes related to the jasmonic acid pathway. Down-regulation of FPS also triggered an iron-deficiency transcriptional response that is consistent with the iron-deficient phenotype observed in FPS-silenced plants. The specific inhibition of the sterol biosynthesis pathway by chemical and genetic blockage mimicked these transcriptional responses, indicating that sterol depletion is the primary cause of the observed alterations. Our results highlight the importance of sterol homeostasis for normal chloroplast development and function and reveal important clues about how isoprenoid and sterol metabolism is integrated within plant physiology and development. PMID

  18. 芥菜型油菜黄化突变体L638-y的遗传及黄化基因gr1的分子标记%Inheritance of chlorophyll-deficient mutant L638-y in Brassica juncea L. and molecular markers for chlorophyll-deficient gene gr1

    Institute of Scientific and Technical Information of China (English)

    田颖; 黄谦心; 刘海衡; 王娇; 安蓉; 刘小娟; 胡胜武

    2012-01-01

    【目的】研究芥菜型油菜黄化突变体L638-y黄化性状的遗传规律,并初步定位黄化基因gr1。【方法】以芥菜型油菜黄化突变体L638-y分别与正常绿色的渭源大黄芥、2598进行杂交,根据杂交F1、F2和BC1材料单株的叶色调查结果进行遗传分析;以从L638-y与2598杂交后代选育得到的近等基因系(Near-isogenic line,NIL)为材料,选用SRAP、SSR、RAPD和AFLP分子标记,采用BSA(Bulk segregant analysis)法,初步定位黄化基因gr1。【结果】芥菜型油菜黄化突变体L638-y的黄化性状受2对隐性核基因控制,将其分别命名为gr1、gr2。将黄化基因gr1初步定位在2个AFLP分子标记EA4TG4和EA7MC1之间,其与2个标记间的遗传距离分别为33.6与21.5cM。【结论】芥菜型油菜黄化突变体L638-y的黄化性状受2对隐性核基因控制,且黄化基因gr1初步定位在EA4TG4和EA7MC1之间。%【Objective】 Inheritance of chlorophyll-deficient mutant L638-y in Brassica juncea and preliminary mapping of chlorophyll-deficient gene gr1 were done in this study.【Method】 The chlorophyll-deficient mutant L638-y was hybridized with the two normal lines,Weiyuandahuangjie and 2598,respectively.The resulting F1,F2 and BC1 populations were used to investigate the inheritance of chlorosis by checking leaf color phenotype in these progenies.The NIL(Near-isogenic line)derived from the progeny of the cross between L638-y and 2598 was used to map one of the chlorophyll-deficient genes-gr1 using SRAP,SSR,RAPD and AFLP with BSA(Bulk segregant analysis)method.【Result】 The chlorosis of L638-y was controlled by two pairs of recessive nuclear genes,namely gr1 and gr2.The chlorophyll-deficient gene gr1 was preliminary mapped between molecular markers EA4TG4 and EA7MC1,and the genetic distances to the markers were 33.6 cM and 21.5 cM,respectively.【Conclusion】 The chlorosis of L638-y was controlled by two pairs of recessive nuclear genes,and the chlorophyll

  19. Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

    Science.gov (United States)

    Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

    2003-08-25

    Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3

  20. Role of magnesium in carbon partitioning and alleviating photooxidative damage.

    Science.gov (United States)

    Cakmak, Ismail; Kirkby, Ernest A

    2008-08-01

    Magnesium (Mg) deficiency exerts a major influence on the partitioning of dry matter and carbohydrates between shoots and roots. One of the very early reactions of plants to Mg deficiency stress is the marked increase in the shoot-to-root dry weight ratio, which is associated with a massive accumulation of carbohydrates in source leaves, especially of sucrose and starch. These higher concentrations of carbohydrates in Mg-deficient leaves together with the accompanying increase in shoot-to-root dry weight ratio are indicative of a severe impairment in phloem export of photoassimilates from source leaves. Studies with common bean and sugar beet plants have shown that Mg plays a fundamental role in phloem loading of sucrose. At a very early stage of Mg deficiency, phloem export of sucrose is severely impaired, an effect that occurs before any noticeable changes in shoot growth, Chl concentration or photosynthetic activity. These findings suggest that accumulation of carbohydrates in Mg-deficient leaves is caused directly by Mg deficiency stress and not as a consequence of reduced sink activity. The role of Mg in the phloem-loading process seems to be specific; resupplying Mg for 12 or 24 h to Mg-deficient plants resulted in a very rapid recovery of sucrose export. It appears that the massive accumulation of carbohydrates and related impairment in photosynthetic CO2 fixation in Mg-deficient leaves cause an over-reduction in the photosynthetic electron transport chain that potentiates the generation of highly reactive O2 species (ROS). Plants respond to Mg deficiency stress by marked increases in antioxidative capacity of leaves, especially under high light intensity, suggesting that ROS generation is stimulated by Mg deficiency in chloroplasts. Accordingly, it has been found that Mg-deficient plants are very susceptible to high light intensity. Exposure of Mg-deficient plants to high light intensity rapidly induced leaf chlorosis and necrosis, an outcome that was

  1. Scientific Opinion on the pest categorisation of the tospoviruses

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Plant Health

    2012-07-01

    Full Text Available

    The European Commission requested EFSA’s Panel on Plant Health to perform the pest categorisation for the 24 viruses of the Tospovirus genus for the EU territory. The following tospoviruses were analysed: Tomato spotted wilt virus (TSWV, Impatiens necrotic spot virus (INSV, Iris yellow spot virus (IYSV, Polygonum ringspot virus (PolRSV, Groundnut ringspot virus (GRSV, Tomato chlorotic spot virus (TCSV, Alstroemeria necrotic streak virus (ANSV, Chrysanthemum stem necrosis virus (CSNV, Melon severe mosaic virus (MSMV, Tomato yellow (fruit ring virus (TYRV, Tomato zonate spot virus (TZSV, Groundnut yellow spot virus (GYSV, Groundnut chlorotic fan-spot virus (GCFSV, Groundnut bud necrosis virus (GBNV, Zucchini lethal chlorosis virus (ZLCV, Capsicum chlorosis virus (CaCV, Watermelon bud necrosis virus (WBNV, Watermelon silver mottle virus (WSMoV, Tomato necrotic ringspot virus (TNRV, Calla lily chlorotic spot virus (CCSV, Melon yellow spot virus (MYSV, Soybean vein necrosis associated virus (SVNaV, Bean necrotic mosaic virus (BeNMV and Pepper necrotic spot virus (PNSV. In reaching its conclusions, the Panel considered four parameters to be of critical importance in the risk assessment area: (i the presence of a tospovirus, (ii the existence of host plants, (iii the existence of thrips vector species and (iv the potential for damage to crops grown in Europe. Based on its analysis, the Panel concluded that the 24 viruses analysed could be allocated to four different risk groups. Seven viruses (GRSV, TCSV, ANSV, CSNV, MSMV, TYRV, TZSV for which both thrips species vectors and natural or experimental hosts crops are present in the EU territory were considered by the Panel to represent the highest risk to the EU territory. In

  2. Resistance to Verticillium dahliae (Kleb.) in the strawberry breeding lines.

    Science.gov (United States)

    Zebrowska, J; Hortyński, J; Cholewa, T; Honcz, K

    2006-01-01

    Verticillium species are soil-borne fungi with worldwide distribution, causing vascular disease that results in severe yield and quality losses in fruit and nut crops, legumes, vegetables, forest trees, and woody and herbaceous ornamentals. Most crop diseases are caused by the two species Verticillium dahliae Klebahn and V. albo-atrum Reinke and Berthier, which differ in morphology, host range, and growth characteristics. The control of Verticillium spp. is especially difficult because they can survive in the soil as resting structures for several years. Cultivation of resistant plant material is the most effective method of the disease elimination. Resistance to Verticillium dahliae Kleb. was examined in the four strawberry breeding lines i.e.'Kent S1', 'Kent o.p.', 'Plena S1', 'Plena o.p'. The strawberry isolate of cv. 'Elsanta' no.1093 of Verticillium dahliae from Pathogen Gene Bank (Poland-Poznań) was used throughout this study. Seedlings of strawberry breeding lines were used for in vitro inoculation at stage of 4 leaves. Their roots were dipped for approximately 1 min in conidial suspensions (inoculum concentration--60 spores at 100x magnification in the microscopic field). Observations of disease symptoms were performed at 15, 30, 45, 60 and 75 days post inoculation. Extent of leaf chlorosis was rated on a scale of 0-4 in which: 0 no symptom. 1 up to 25% chlorotic leaves. 2 up to 50% chlorotic leaves. 3 up to 75% chlorotic leaves. 4 up to 100% chlorotic leaves. Plant response to in vitro inoculation of V. dahliae was different and depended on the breeding line. The most susceptible breeding line was 'Plena S1' and the most resistant was the line 'Kent o.p'. The line 'Kent S1' was more susceptible than the last one, but much more resistant than the line 'Plena o.p'. Seedlings without disease symptoms were observed in all examined lines at 15 and 30 days post inoculation At 45 days post inoculation no plant without disease symptoms was observed. Disease

  3. PHYSIOLOGICAL AND BIOCHEMICAL CHANGES AT FOLIAR LEVEL INDUCED BY ATMOSPHERIC POLLUTANTS ON SAMPLES OF AESCULUS HIPPOCASTANUM L. FROM IAŞI CITY AREA

    Directory of Open Access Journals (Sweden)

    Bogdan Soltuzu

    2013-12-01

    Full Text Available We present in this paper some physiological changes (photosynthetic and transpiration processes intensity and biochemical (content of photo-assimilating pigments induced at foliar level by some pollutants in samples of Aesculus hippocastanum L. cultivated for ornamental purposes across the five air quality monitoring stations in Iasi city area. Pollutants monitored by the five stations are represented by gaseous (sulfur dioxide, carbon dioxide, nitrogen dioxide, ozone and solid pollutants (dust prone to sedimentation. Measurements were made "in vivo", as well on fresh material covering vegetation periods of years 2012 and 2013. The necrosis and   the inducted foliar chlorosis by polluting agents represent the clear materialization of some profound physiological modifications which disturb the photo-assimilating structures and assimilator  pigments. The results lead to the conclusion that the amount of chlorophyll a and b and the intensity of photosynthesis aren`t always correlated, as already known from literature. The most obvious results of pollutants influence occurred for the individuals situated at the traffic station Podul de Piatră, where SO2 and particulate solids in suspension are the predominating pollutants and this fact states that the traffic pollutants are the most destructive.

  4. Cigarrinhas dos Citros, Vetoras da Bactéria Xylella fastidiosa Wells et al.: Pragas Potenciais para a Citricultura Sergipana

    Directory of Open Access Journals (Sweden)

    Ruberval Azevedo

    2015-04-01

    Abstract. The citrus industry in Brazil plays a role of great economic, social, generating jobs, income and development. Brazil is the largest producer of citrus, the State of Sergipe stands out in 5th place in national production. Among the many pest problems faced by Brazilian citrus is Citrus Variegated Chlorosis (CVC, known as the yellowing caused by the bacterium Xylella fastidiosa Wells et al. The CVC was officially identified in Brazil in 1987, in orchards of “Triângulo Mineiro” and North and northwest of the state of São Paulo. In the Northeast Region of Brazil, was found in 1996 in the municipality of Boquim Sergipe, and Bahia in 1997, the municipalities of Rio Real and Itapicuru. The aim was to review the literature on the species of leafhoppers vectors of CVC, and verify that occur in the state of Sergipe. The first symptoms are seen in the leaves, then go for the fruits and end up affecting the entire plant, and to be perceived can take between five months and two years. The main vectors of X. fastidiosa in citrus are the sharpshooters of the family Cicadellidae. In Brazil 12 sharpshooters species have already been confirmed. For the state of Sergipe, is scarce information about the Cicadellidae vectors, the data are limited to the northern coast of Bahia, except for vague quote about four genus (Oncometropia, Acrogonia, Dilobopterus and Homolodisca and three species (Homolodisca ignorata Melichar, Acrogonia sp. and Homolodisca spottii Takiya, Cavichioli & McKamey.

  5. GEOSTATISTICAL MODEL EVALUATION OF LIMING ON OSIJEK-BARANYA COUNTY EXAMPLE

    Directory of Open Access Journals (Sweden)

    Vladimir Vukadinović

    2008-12-01

    Full Text Available Unfavorable pH of soil is the main reason for several different problems in debalance of mineral nutrition which can cause many problems in plant growth; such as leaves and fruit chlorosis and necrosis; etc. Therefore; liming as a measure for improving amount of acids soils must be conducted very carefully; with detail chemical soil analyses. This paper presents a segment of computer model for liming recommendation at the example of Osijek-Baranya County. Results of liming recommendation were obtained by geostatistical interpolation method – kriging. Totals of 9023 soil samples were analyzed in the period 2003–2007. The substitution acidity average was 5.49 (minimum 3.41 to maximum 8.20. Kriging shown that 241 379 ha (58.3% area of Osijek-Baranya County were acids soil. Therefore 90 593 ha have substitution acidity lower than 4.5 and 150 786 ha have pH KCl between 4.5 and 5.5. Except carbocalk; other "slowly-effect" materials can be recommended for liming; especially for vineyards and orchards.

  6. In vitro selection in resistance breeding of strawberry (Fragaria x ananassa duch.).

    Science.gov (United States)

    Zebrowska, Jadwiga Irena

    2010-01-01

    Genetic resistance to pathogenetic soil-borne fungus Verticillium dahliae Kleb. was examined in two strawberry somaclones. Strawberry somaclones were obtained in sterile culture from runner tips of cultivars 'Merton Dawn' and 'Selva'. In vitro selection was performed with the use of homogenate of liquid cultures of Verticillium dahliae. Microplants of both somaclones were inoculated at stage of 4. Leaves. Disease symptoms were observed at 15., 30., 45., 60. and 75. days post inoculation. Extent of leaf chlorosis was rated on a scale of 0-4. Under the controlled in vitro culture conditions a different response to infection by this pathogenic fungus was observed. After 75. days post inoculation the contribution of necrotic plants in somaclone of 'Merton Dawn' reached the value of 76%, whereas in somaclone of 'Selva' this value reached 86%. In control somaclones of 'Merton Dawn' and 'Selva' the contribution of necrotic plants after 75. days post mock-inoculation with sterile distilled water reached the considerably lower value of 13%. These results revealed that somaclone of 'Merton Dawn' was more genetically resistant to infection by V. dahliae than somaclone of 'Selva'. The observed response to in vitro infection caused by Verticillium dahliae in examined somaclones was similar in comparison with original cultivars. Furthermore, somaclonal variation induced in tissue cultured strawberry was sufficient to select variants that showed enhanced genetic resistance to Verticillium wilt caused by V. dahliae. In vitro selection can be efficiently used as an alternative program to conventional resistance breeding in strawberry.

  7. Potassium Transporter KUP7 Is Involved in K(+) Acquisition and Translocation in Arabidopsis Root under K(+)-Limited Conditions.

    Science.gov (United States)

    Han, Min; Wu, Wei; Wu, Wei-Hua; Wang, Yi

    2016-03-01

    Potassium (K(+)) is one of the essential macronutrients for plant growth and development. K(+) uptake from environment and K(+) translocation in plants are conducted by K(+) channels and transporters. In this study, we demonstrated that KT/HAK/KUP transporter KUP7 plays crucial roles in K(+) uptake and translocation in Arabidopsis root. The kup7 mutant exhibited a sensitive phenotype on low-K(+) medium, whose leaves showed chlorosis symptoms compared with wild-type plants. Loss of function of KUP7 led to a reduction of K(+) uptake rate and K(+) content in xylem sap under K(+)-deficient conditions. Thus, the K(+) content in kup7 shoot was significantly reduced under low-K(+) conditions. Localization analysis revealed that KUP7 was predominantly targeted to the plasma membrane. The complementation assay in yeast suggested that KUP7 could mediate K(+) transport. In addition, phosphorylation on S80, S719, and S721 was important for KUP7 activity. KUP7 was ubiquitously expressed in many organs/tissues, and showed a higher expression level in Arabidopsis root. Together, our data demonstrated that KUP7 is crucial for K(+) uptake in Arabidopsis root and might be also involved in K(+) transport into xylem sap, affecting K(+) translocation from root toward shoot, especially under K(+)-limited conditions. PMID:26851373

  8. Presence of rose spring dwarf-associated virus in Chile: partial genome sequence and detection in roses and their colonizing aphids.

    Science.gov (United States)

    Rivera, Paulina A; Engel, Esteban A

    2010-10-01

    Rose is one of the most important cut flowers produced in the world. It is also grown in landscape plantings and public gardens for ornamental purposes. However, there is no detailed information available about viruses infecting roses in Chile. In order to gain insight about the viruses that could be present, a plant showing yellow vein chlorosis in its leaves was collected from a garden in Santiago. Double-stranded RNA (dsRNA) was isolated and after a random primed RT-PCR amplification procedure followed by sequencing, Rose spring dwarf-associated virus (RSDaV) presence was established. In order to widen the survey, several additional symptomatic and asymptomatic plants as well as aphids were screened by RT-PCR using two different pairs of virus-specific primers. RSDaV was detected in 24% of the analyzed samples. To our knowledge, this is the first report of RSDaV in Chilean rose plants and Rhodobium porosum (Sanderson) aphids. PMID:20607379

  9. Detection and discrimination of members of the family Luteoviridae by real-time PCR and SYBR® GreenER™ melting curve analysis.

    Science.gov (United States)

    Chomic, Anastasija; Winder, Louise; Armstrong, Karen F; Pearson, Michael N; Hampton, John G

    2011-01-01

    This study investigated the suitability of a two step real-time RT-PCR melting curve analysis as a tool for the detection and discrimination of nine species in the plant virus family Luteoviridae, being Soybean dwarf virus [SbDV], Bean leafroll virus [BLRV], Beet chlorosis virus [BChV], Beet mild yellowing virus [BMYV], Beet western yellows virus [BWYV], Cereal yellow dwarf virus-RPV [CYDV-RPV], Cucurbit aphid-borne yellows virus [CABYV], Potato leafroll virus [PLRV] and Turnip yellows virus [TuYV]. Melting temperature and shape of the melting peak were analysed for 68 bp and 148 bp coat protein gene amplicons using SYBR® GreenER™ fluorescent dye. Specific melting peaks with unique melting temperature were observed for the various species of the family Luteoviridae using the 68 bp amplicon, but not with the 148 bp amplicon. Due to the high variability of sequences for some members of this family, different melting temperatures were also observed between different isolates of the species CYDV-RPV and TuYV. Nevertheless, discrimination between species was achieved for SbDV, BLRV, BChV, BMYV, CABYV and either PLRV or BWYV. Melting curve analysis, in this study, is a faster and more discriminatory alternative to gel electrophoresis of end-point PCR products for the detection of Luteoviridae infection. PMID:20933015

  10. A variant of Rubus yellow net virus with altered genomic organization.

    Science.gov (United States)

    Diaz-Lara, Alfredo; Mosier, Nola J; Keller, Karen E; Martin, Robert R

    2015-02-01

    Rubus yellow net virus (RYNV) is a member of the genus Badnavirus (family: Caulimoviridae). RYNV infects Rubus species causing chlorosis of the tissue along the leaf veins, giving an unevenly distributed netted symptom in some cultivars of red and black raspberry. Recently, a strain of RYNV was sequenced from a Rubus idaeus plant in Alberta, Canada, exhibiting such symptoms. The viral genome contained seven open reading frames (ORFs) with five of them in the sense-strand, including a large polyprotein. Here we describe a graft-transmissible strain of RYNV from Europe infecting cultivar 'Baumforth's Seedling A' (named RYNV-BS), which was sequenced using rolling circle amplification, enzymatic digestion, cloning and primer walking, and it was resequenced at a 5X coverage. This sequence was then compared with the RYNV-Ca genome and significant differences were observed. Genomic analysis identified differences in the arrangement of coding regions, promoter elements, and presence of motifs. The genomic organization of RYNV-BS consisted of five ORFs (four ORFs in the sense-strand and one ORF in the antisense-strand). ORFs 1, 2, and 3 showed a high degree of homology to RYNV-Ca, while ORFs 4 and 6 of RYNV-BS were quite distinct. Also, the predicted ORFs 5 and 7 in the RYNV-Ca were absent in the RYNV-BS sequence. These differences may account for the lack of aphid transmissibility of RYNV-BS. PMID:25480633

  11. Losses of leaf area owing to herbivory and early senescence in three tree species along a winter temperature gradient

    Science.gov (United States)

    González-Zurdo, P.; Escudero, A.; Nuñez, R.; Mediavilla, S.

    2016-03-01

    In temperate climates, evergreen leaves have to survive throughout low temperature winter periods. Freezing and chilling injuries can lead to accelerated senescence of part of the leaf surface, which contributes to a reduction of the lifespan of the photosynthetic machinery and of leaf lifetime carbon gain. Low temperatures are also associated with changes in foliar chemistry and morphology that affect consumption by herbivores. Therefore, the severity of foliar area losses caused by accelerated senescence and herbivory can change along winter temperature gradients. The aim of this study is to analyse such responses in the leaves of three evergreen species (Quercus ilex, Q. suber and Pinus pinaster) along a climatic gradient. The leaves of all three species presented increased leaf mass per area (LMA) and higher concentrations of structural carbohydrates in cooler areas. Only the two oak species showed visible symptoms of damage caused by herbivory, this being less intense at the coldest sites. The leaves of all three species presented chlorotic and necrotic spots that increased in size with leaf age. The foliar surface affected by chlorosis and necrosis was larger at the sites with the coldest winters. Therefore, the effects of the winter cold on the lifespan of the photosynthetic machinery were contradictory: losses of leaf area due to accelerated senescence increased, but there was a decrease in losses caused by herbivory. The final consequences for carbon assimilation strongly depend on the exact timing of the appearance of the damage resulting from low temperature and grazing by herbivores.

  12. Foxtail Mosaic Virus-Induced Gene Silencing in Monocot Plants1[OPEN

    Science.gov (United States)

    Liu, Na; Xie, Ke; Jia, Qi; Zhao, Jinping; Chen, Tianyuan; Li, Huangai; Wei, Xiang; Diao, Xianmin; Hong, Yiguo

    2016-01-01

    Virus-induced gene silencing (VIGS) is a powerful technique to study gene function in plants. However, very few VIGS vectors are available for monocot plants. Here we report that Foxtail mosaic virus (FoMV) can be engineered as an effective VIGS system to induce efficient silencing of endogenous genes in monocot plants including barley (Hordeum vulgare L.), wheat (Triticum aestivum) and foxtail millet (Setaria italica). This is evidenced by FoMV-based silencing of phytoene desaturase (PDS) and magnesium chelatase in barley, of PDS and Cloroplastos alterados1 in foxtail millet and wheat, and of an additional gene IspH in foxtail millet. Silencing of these genes resulted in photobleached or chlorosis phenotypes in barley, wheat, and foxtail millet. Furthermore, our FoMV-based gene silencing is the first VIGS system reported for foxtail millet, an important C4 model plant. It may provide an efficient toolbox for high-throughput functional genomics in economically important monocot crops. PMID:27225900

  13. CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.

    Science.gov (United States)

    Tian, Qiuying; Zhang, Xinxin; Yang, An; Wang, Tianzuo; Zhang, Wen-Hao

    2016-05-01

    Iron deficiency is one of the major limiting factors affecting quality and production of crops in calcareous soils. Numerous signaling molecules and transcription factors have been demonstrated to play a regulatory role in adaptation of plants to iron deficiency. However, the mechanisms underlying the iron deficiency-induced physiological processes remain to be fully dissected. Here, we demonstrated that the protein kinase CIPK23 was involved in iron acquisition. Lesion of CIPK23 rendered Arabidopsis mutants hypersensitive to iron deficiency, as evidenced by stronger chlorosis in young leaves and lower iron concentration than wild-type plants under iron-deficient conditions by down-regulating ferric chelate reductase activity. We found that iron deficiency evoked an increase in cytosolic Ca(2+) concentration and the elevated Ca(2+) would bind to CBL1/CBL9, leading to activation of CIPK23. These novel findings highlight the involvement of calcium-dependent CBL-CIPK23 complexes in the regulation of iron acquisition. Moreover, mutation of CIPK23 led to changes in contents of mineral elements, suggesting that CBL-CIPK23 complexes could be as "nutritional sensors" to sense and regulate the mineral homeostasis in Arabisopsis. PMID:26993237

  14. Iron Deficiency-induced Increase of Root Branching Contributes to the Enhanced Root Ferric Chelate Reductase Activity

    Institute of Scientific and Technical Information of China (English)

    Chong-Wei Jin; Wei-Wei Chen; Zhi-Bin Meng; Shao-Jian Zheng

    2008-01-01

    In various plant species, Fe deficiency increases lateral root branching. However, whether this morphological alteration contributes to the Fe deficiency-induced physiological responses still remains to be demonstrated. In the present research, we demonstrated that the lateral root development of red clover (Trifolium pretense L.) was significantly enhanced by Fe deficient treatment, and the total lateral root number correlated well with the Fe deficiency-induced ferric chelate reductase (FCR) activity. By analyzing the results from Dasgan et al. (2002), we also found that although the two tomato genotypes line227/1 (P1) and Roza (P2) and their reciprocal F1 hybrid lines ("P1 × P2" and "P2 × P1 ") were cultured under two different lower Fe conditions (10-6 and 10-7 M FeEDDHA), their FCR activities are significantly correlated with the lateral root number. More interestingly, the -Fe chlorosis tolerant ability of these four tomato lines displays similar trends with the lateral root density. Taking these results together, it was proposed that the Fe deficiency-induced increases of the lateral root should play an important role in resistance to Fe deficiency, which may act as harnesses of a useful trait for the selection and breeding of more Fe-efficiant crops among the genotypes that have evolved a Fe deficiency-induced Fe uptake system.

  15. Near-isogenic lines of Triticum aestivum with distinct modes of resistance exhibit dissimilar transcriptional regulation during Diuraphis noxia feeding

    Directory of Open Access Journals (Sweden)

    Anna-Maria Botha

    2014-10-01

    Full Text Available Russian wheat aphid (Diuraphis noxia, Kurdjumov feeding on susceptible Triticum aestivum L. leads to leaf rolling, chlorosis and plant death – symptoms not present in resistant lines. Although the effects of several D. noxia (Dn resistance genes are known, none have been isolated or characterized. Wheat varieties expressing different Dn genes exhibit distinct modes of D. noxia resistance, such as antibiosis (Dn1, tolerance (Dn2, and antixenosis (Dn5. However, the mechanism whereby feeding aphids are perceived, and how subsequent transcriptional responses are partitioned into resistance categories, remains unclear. Here we report on downstream events in near-isogenic wheat lines containing different Dn genes after D. noxia biotype SA1 feeding. Transcripts involved in stress, signal transduction, photosynthesis, metabolism and gene regulation were differentially regulated during D. noxia feeding. Expression analyses using RT-qPCR and RNA hybridization, as well as enzyme activity profiling, provide evidence that the timing and intensity of pathways induced are critical in the development of particular modes of resistance. Pathways involved include the generation of kinase signalling cascades that lead to a sustained oxidative burst, and a hypersensitive response that is active during antibiosis. Tolerance is a passive resistance mechanism that acts through repair or de novo synthesis of photosystem proteins. Results further suggest that ethylene-mediated pathways are possibly involved in generating volatile compounds and cell wall fortification during the antixenosic response.

  16. Crystal structure of NblA from Anabaena sp. PCC 7120, a small protein playing a key role in phycobilisome degradation.

    Science.gov (United States)

    Bienert, Ralf; Baier, Kerstin; Volkmer, Rudolf; Lockau, Wolfgang; Heinemann, Udo

    2006-02-24

    Cyanobacterial light-harvesting complexes, the phycobilisomes, are proteolytically degraded when the organisms are starved for combined nitrogen, a process referred to as chlorosis or bleaching. Gene nblA, present in all phycobilisome-containing organisms, encodes a protein of about 7 kDa that plays a key role in phycobilisome degradation. The mode of action of NblA in this degradation process is poorly understood. Here we presented the 1.8-A crystal structure of NblA from Anabaena sp. PCC 7120. In the crystal, NblA is present as a four-helix bundle formed by dimers, the basic structural units. By using pull-down assays with immobilized NblA and peptide scanning, we showed that NblA specifically binds to the alpha-subunits of phycocyanin and phycoerythrocyanin, the main building blocks of the phycobilisome rod structure. By site-directed mutagenesis, we identified amino acid residues in NblA that are involved in phycobilisome binding. The results provided evidence that NblA is directly involved in phycobilisome degradation, and the results allowed us to present a model that gives insight into the interaction of this small protein with the phycobilisomes.

  17. Biomonitoring of Epilobium hirsutum L. Health Status to Assess Water Ecotoxicity in Constructed Wetlands Treating Mixtures of Contaminants

    Directory of Open Access Journals (Sweden)

    Anna Guittonny-Philippe

    2015-02-01

    Full Text Available For the treatment of wastewater containing organic pollutants and metals in constructed wetlands (CWs, phytoindicators may help in guiding management practices for plants and optimizing phytoremediation processes. Hairy willow-herb (Epilobium hirsutum L. is a fast growing species commonly found in European CWs that could constitute a suitable phytoindicator of metal toxicity. E. hirsutum was exposed for 113 days in microcosm CWs, to a metal and metalloid mixture (MPM, containing Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Zn, an organic pollutant mixture (OPM, containing hydrocarbonsC10-C40, phenanthrene, pyrene, anionic detergent LAS and an organic pollutant and metal and metalloid mixture (OMPM, separately and at concentration levels mimicking levels of industrial effluents. Analyses of metal and As concentrations in biomass, and different biometric and physiological measurements were performed. Results showed that metal uptake patterns were affected by the type of pollutant mixture, resulting in variation of toxicity symptoms in E. hirsutum plants. Some of them appeared to be similar under MPM and OMPM conditions (leaf chlorosis and tip-burning, decrease of green leaf proportion, while others were characteristic of each pollutant mixture (MPM: Decrease of water content, increase of phenol content; OMPM: reduction of limb length, inhibition of vegetative reproduction, increase of chlorophyll content and Nitrogen balance index. Results emphasize the potential of E. hirsutum as a bioindicator species to be used in European CWs treating water with metal, metalloid and organic pollutants.

  18. Characterization and quantification of racemic and meso-ethylenediamine-N,N'-bis(2-hydroxy-5-sulfophenylacetic) acid/iron (III) by ion-pair ultra-high performance liquid chromatography coupled with diode array detector and electrospray tandem mass spectrometry.

    Science.gov (United States)

    Biasone, Alessandro; Cianci, Giusto; Di Tommaso, Donata; Piaggesi, Alberto; Tagliavini, Emilio; Galletti, Paola; Moretti, Fabio

    2013-03-22

    EDDHSA/Fe is a promising substitute of EDDHA/Fe to fight iron chlorosis. o,o-EDDHSA structure contains two chiral carbons giving the racemic and meso couples of stereoisomers. Ion-pair HPLC and UHPLC-UV/Vis-ESI-MS/MS methods were developed for the determination of racemic and meso-o,o-EDDHSA/Fe in commercial samples of chelates. The lack of a commercial EDDHSA standard was overcome by sulfonation of a commercial available o,o-EDDHA standard and subsequent quantification by (1)H-NMR. Assignment of configurations was carried out starting from racemic and meso-o,o-EDDHA/Fe by direct sulfonation to give the corresponding o,o-EDDHSA/Fe isomers. The performances of these methods were assessed in terms of intra and inter-day precision, linearity and selectivity. The high selectivity and lower detection limit (nanomolar) of the UHPLC-ESI-MS/MS method could allow to deepen the knowledge relative to meso and rac-o,o-EDDHSA/Fe interactions with plants, its fate in different soil conditions, its mobility and other environmental aspects. PMID:23411145

  19. Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

    Science.gov (United States)

    Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

    2002-01-16

    Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved. PMID:11782196

  20. The Sesquiterpenes β-Caryophyllene and Caryophyllene Oxide Isolated from Senecio salignus Act as Phytogrowth and Photosynthesis Inhibitors

    Directory of Open Access Journals (Sweden)

    Blas Lotina-Hennsen

    2012-02-01

    Full Text Available The n-hexane extract of S. salignus plants inhibited ATP synthesis and two sesquiterpenes, the b-caryophyllene (1 and caryophyllene oxide (2 were isolated from this nonpolar fraction. Compound 1 inhibited by 42% the root elongation of Physalis ixocarpa seedlings at 50 µg/mL and by 53% at 150 µg/mL, whereas at 150 µg/mL this compound only inhibited root elongation of Echinochloa crus-galli by 30%. On the other hand, compound 2 had no effect on either germination or root and stem growth of E. cruss galli and P. ixocarpa. However, 1 and 2 inhibited the dry biomass of P. ixocarpa plants grown for 18 days previous to treatment and it was found that 1 was the most active biomass inhibitor. The Chl a fluorescence transient in vivo experiment indicates that 1 (100 µg/mL has a major effect at 72 h after treatment on leaves of P. ixocarpa plants by inhibiting photosystem II (PS II transforming active reaction centers to “heat sinks” or the formation of silent reaction centers unable to reduce QA. b-Caryophyllene also induces chlorosis on treated leaves.

  1. The sesquiterpenes β-caryophyllene and caryophyllene oxide isolated from Senecio salignus act as phytogrowth and photosynthesis inhibitors.

    Science.gov (United States)

    Sánchez-Muñoz, B Arturo; Aguilar, Maria Isabel; King-Díaz, Beatriz; Rivero, José Fausto; Lotina-Hennsen, Blas

    2012-01-01

    The n-hexane extract of S. salignus plants inhibited ATP synthesis and two sesquiterpenes, the β-caryophyllene (1) and caryophyllene oxide (2) were isolated from this nonpolar fraction. Compound 1 inhibited by 42% the root elongation of Physalis ixocarpa seedlings at 50 µg/mL and by 53% at 150 µg/mL, whereas at 150 µg/mL this compound only inhibited root elongation of Echinochloa crus-galli by 30%. On the other hand, compound 2 had no effect on either germination or root and stem growth of E. cruss galli and P. ixocarpa. However, 1 and 2 inhibited the dry biomass of P. ixocarpa plants grown for 18 days previous to treatment and it was found that 1 was the most active biomass inhibitor. The Chl a fluorescence transient in vivo experiment indicates that 1 (100 µg/mL) has a major effect at 72 h after treatment on leaves of P. ixocarpa plants by inhibiting photosystem II (PS II) transforming active reaction centers to "heat sinks" or the formation of silent reaction centers unable to reduce Q(A). β-Caryophyllene also induces chlorosis on treated leaves. PMID:22310166

  2. Lichens as biological monitors in the Los Azufres geothermal field, Michoacan, Mexico; Liquenes como indicadores biologicos en el campo geotermico Los Azufres, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Peralta, Marlene; Chavez Carmona, Arturo [Universidad Michoacana de San Nicolas de Hidalgo, Morelia (Mexico)

    1995-09-01

    The results obtained in the monitoring of the atmospheric emissions of the Los Azufres geothermal field in Michoacan State, Mexico utilizing lichens as monitors of the presence of sulphur and arsenic, at the areas near geothermal sites, both under evaluation and production, are presented. The results are based on symptoms which included: chlorosis, necrosis, brown and reddish spots, loss of adherence to substrate, thalli disintegration and disappearance of sensitive species; and also on the amounts of sulphur and arsenic contained in the lichens thallus. [Espanol] Se presentan los resultados obtenidos en el monitoreo de las emisiones atmosfericas del campo geotermico Los Azufres, Michoacan, Mexico en el que se utilizaron liquenes como indicadores de la presencia de azufre y arsenico, en las areas cercanas a los sitios de pozos geotermicos tanto en evaluacion como en produccion. Los resultados estan basados en sintomas que incluyen clorosis, necrosis, manchas cafes y rojizas, perdida de adherencia al sustrato, desintegracion del talo y desaparicion de especies sensibles; asi como en los contenidos de azufre y arsenico en los talos liquenicos.

  3. Transcriptome analysis of Nicotiana tabacum infected by Cucumber mosaic virus during systemic symptom development.

    Directory of Open Access Journals (Sweden)

    Jie Lu

    Full Text Available Virus infection of plants may induce a variety of disease symptoms. However, little is known about the molecular mechanism of systemic symptom development in infected plants. Here we performed the first next-generation sequencing study to identify gene expression changes associated with disease development in tobacco plants (Nicotiana tabacum cv. Xanthi nc induced by infection with the M strain of Cucumber mosaic virus (M-CMV. Analysis of the tobacco transcriptome by RNA-Seq identified 95,916 unigenes, 34,408 of which were new transcripts by database searches. Deep sequencing was subsequently used to compare the digital gene expression (DGE profiles of the healthy plants with the infected plants at six sequential disease development stages, including vein clearing, mosaic, severe chlorosis, partial and complete recovery, and secondary mosaic. Thousands of differentially expressed genes were identified, and KEGG pathway analysis of these genes suggested that many biological processes, such as photosynthesis, pigment metabolism and plant-pathogen interaction, were involved in systemic symptom development. Our systematic analysis provides comprehensive transcriptomic information regarding systemic symptom development in virus-infected plants. This information will help further our understanding of the detailed mechanisms of plant responses to viral infection.

  4. Maize ZmFDR3 localized in chloroplasts is involved in iron transport

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency. Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots. Here,we describe the functional characterization of one of the genes identified in the screen,ZmFDR3 (Zea maize Fe-deficiency-related). Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport. ZmFDR3 contains a domain found in FliN-proteins of the type III secretion system and is predicted to localize to the thylakoid of plastids. Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots,stems and leaves,with high expression found in guard cell chloroplasts. Transgenic tobacco expressing a 35S-ZmFDR3 construct contains elevated iron content,displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type. Together,these results suggest that ZmFDR3 functions in chloroplast iron transport.

  5. Genetic Interactions Reveal that Specific Defects of Chloroplast Translation are Associated with the Suppression of var2-Mediated Leaf Variegation

    Institute of Scientific and Technical Information of China (English)

    Xiayan Liu; Mengdi Zheng; Rui Wang; Ruijuan Wang; Lijun An; Steve R. Rodermel; Fei Yu

    2013-01-01

    Arabidopsis thaliana L. yellow variegated (var2) mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGATION8 (SVR8), which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr8 23S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, S21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2 variegation and the existence of complex genetic interactions in chloroplast development.

  6. New host-virus relations between different Solanum species and viruses.

    Science.gov (United States)

    Takács, A P; Kazinczi, G; Horváth, J; Pribék, D

    2001-01-01

    We have studied the susceptibility or resistance of Solanum capsicastrum Link. et Schauer, S. comatum Sendt., S. dulcamara L., S. luteum Mill., S. malacoxylon Sendt. and S. nigrum L. to three aphid transmissible viruses [alfalfa mosaic alfamovirus (AMV), potato M. carlavirus (PVM) and potato S carlavirus (PVS)]. Out of the species, S. capsicastrum, S. comatum, S. dulcamara, S. malacoxylon and S. nigrum to AMV, S. capsicastrum and S. malacoxylon to PVM and S. capsicastrum, S. luteum and S. nigrum to PVS showed the highest resistance (immunity). Symptoms could not be seen on inoculated plants and the virus could be detected by them neither by serological nor biological tests. Solanum luteum plants were susceptible to AMV. Solanum comatum, S. dulcamara, S. luteum and S. nigrum showed susceptibility to PVM. Solanum comatum and S. dulcamara were susceptible to PVS. Symptoms (necrotic lesions, mosaic and chlorosis) could be seen after inoculation and the absorbance values (DAS-ELISA) exceeded twice that of the healthy control samples during the serological tests. PMID:12425036

  7. CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.

    Science.gov (United States)

    Tian, Qiuying; Zhang, Xinxin; Yang, An; Wang, Tianzuo; Zhang, Wen-Hao

    2016-05-01

    Iron deficiency is one of the major limiting factors affecting quality and production of crops in calcareous soils. Numerous signaling molecules and transcription factors have been demonstrated to play a regulatory role in adaptation of plants to iron deficiency. However, the mechanisms underlying the iron deficiency-induced physiological processes remain to be fully dissected. Here, we demonstrated that the protein kinase CIPK23 was involved in iron acquisition. Lesion of CIPK23 rendered Arabidopsis mutants hypersensitive to iron deficiency, as evidenced by stronger chlorosis in young leaves and lower iron concentration than wild-type plants under iron-deficient conditions by down-regulating ferric chelate reductase activity. We found that iron deficiency evoked an increase in cytosolic Ca(2+) concentration and the elevated Ca(2+) would bind to CBL1/CBL9, leading to activation of CIPK23. These novel findings highlight the involvement of calcium-dependent CBL-CIPK23 complexes in the regulation of iron acquisition. Moreover, mutation of CIPK23 led to changes in contents of mineral elements, suggesting that CBL-CIPK23 complexes could be as "nutritional sensors" to sense and regulate the mineral homeostasis in Arabisopsis.

  8. Physiological responses in roots of the grapevine rootstock 140 Ruggeri subjected to Fe deficiency and Fe-heme nutrition.

    Science.gov (United States)

    López-Rayo, Sandra; Di Foggia, Michele; Rodrigues Moreira, Erica; Donnini, Silvia; Bombai, Giuseppe; Filippini, Gianfranco; Pisi, Annamaria; Rombolà, Adamo D

    2015-11-01

    Iron (Fe)-heme containing fertilizers can effectively prevent Fe deficiency. This paper aims to investigate root physiological responses after a short period of Fe-heme nutrition and Fe deficiency under two pH conditions (with or without HEPES) in the Fe chlorosis-tolerant grapevine rootstock 140 Ruggeri. Organic acids in root exudates, Fe reduction capacity, both roots and root exudates contributions, together with other physiological parameters associated to plant Fe status were evaluated in plants grown in hydroponics. Analyses of root tips by SEM, and Raman and IR spectra of the precipitates of Fe-heme fertilizers were performed. The physiological responses adopted by the tolerant 140 Ruggeri to the application of Fe-heme indicated an increased Fe reduction capacity of the roots. This is the first report showing oxalic, tartaric, malic and ascorbic as major organic acids in Vitis spp. root exudates. Plants reacted to Fe deficiency condition exuding a higher amount of ascorbic acid in the rhizosphere. The presence of HEPES in the medium favoured the malic acid exudation. The lowest concentration of oxalic acid was found in exudates of plants subjected to Fe-heme and could be associated to a higher accumulation in their root tips visualized by SEM analysis. PMID:26276277

  9. Impact of copper toxicity on stone-head cabbage (Brassica oleracea var. capitata) in hydroponics.

    Science.gov (United States)

    Ali, Sajid; Shahbaz, Muhammad; Shahzad, Ahmad Naeem; Khan, Hafiz Azhar Ali; Anees, Moazzam; Haider, Muhammad Saleem; Fatima, Ammara

    2015-01-01

    Arable soils are frequently subjected to contamination with copper as the consequence of imbalanced fertilization with manure and organic fertilizers and/or extensive use of copper-containing fungicides. In the present study, the exposure of stone-head cabbage (Brassica oleracea var. capitata) to elevated Cu(2+) levels resulted in leaf chlorosis and lesser biomass yield at ≥2 µ M. Root nitrate content was not statistically affected by Cu(2+) levels, although it was substantially decreased at ≥5 µ M Cu(2+) in the shoot. The decrease in nitrate contents can be related to lower nitrate uptake rates because of growth inhibition by Cu-toxicity. Shoot sulfate content increased strongly at ≥2 µ M Cu(2+) indicating an increase in demand for sulfur under Cu stress. Furthermore, at ≥2 µM concentration, concentration of water-soluble non-protein thiol increased markedly in the roots and to a smaller level in the shoot. When exposed to elevated concentrations of Cu(2+) the improved sulfate and water-soluble non-protein thiols need further studies for the evaluation of their direct relation with the synthesis of metal-chelating compounds (i.e., phytochelatins). PMID:26290787

  10. Citrus plastid-related gene profiling based on expressed sequence tag analyses

    Directory of Open Access Journals (Sweden)

    Tercilio Calsa Jr.

    2007-01-01

    Full Text Available Plastid-related sequences, derived from putative nuclear or plastome genes, were searched in a large collection of expressed sequence tags (ESTs and genomic sequences from the Citrus Biotechnology initiative in Brazil. The identified putative Citrus chloroplast gene sequences were compared to those from Arabidopsis, Eucalyptus and Pinus. Differential expression profiling for plastid-directed nuclear-encoded proteins and photosynthesis-related gene expression variation between Citrus sinensis and Citrus reticulata, when inoculated or not with Xylella fastidiosa, were also analyzed. Presumed Citrus plastome regions were more similar to Eucalyptus. Some putative genes appeared to be preferentially expressed in vegetative tissues (leaves and bark or in reproductive organs (flowers and fruits. Genes preferentially expressed in fruit and flower may be associated with hypothetical physiological functions. Expression pattern clustering analysis suggested that photosynthesis- and carbon fixation-related genes appeared to be up- or down-regulated in a resistant or susceptible Citrus species after Xylella inoculation in comparison to non-infected controls, generating novel information which may be helpful to develop novel genetic manipulation strategies to control Citrus variegated chlorosis (CVC.

  11. Analysis of expressed sequence tags from Citrus sinensis L. Osbeck infected with Xylella fastidiosa

    Directory of Open Access Journals (Sweden)

    Alessandra A. de Souza

    2007-01-01

    Full Text Available In order to understand the genetic responses resulting from physiological changes that occur in plants displaying citrus variegated chlorosis (CVC symptoms, we adopted a strategy of comparing two EST libraries from sweet orange [Citrus sinensis (L. Osbeck]. One of them was prepared with plants showing typical CVC symptoms caused by Xylella fastidiosa and the other with non-inoculated plants. We obtained 15,944 ESTs by sequencing the two cDNA libraries. Using an in silico hybridization strategy, 37 genes were found to have significant variation at the transcriptional level. Within this subset, 21 were up-regulated and 16 were down-regulated in plants with CVC. The main functional categories of the down-regulated transcripts in plants with CVC were associated with metabolism, protein modification, energy and transport facilitation. The majority of the up-regulated transcripts were associated with metabolism and defense response. Some transcripts associated with adaptation to stress conditions were up-regulated in plants with CVC and could explain why plants remain alive even under severe water and nutritional stress. Others of the up-regulated transcripts are related to defense response suggesting that sweet orange plants activate their defense machinery. The genes associated with stress response might be expressed as part of a secondary response related to physiological alterations caused by the infection.

  12. AtSWEET4, a hexose facilitator, mediates sugar transport to axial sinks and affects plant development.

    Science.gov (United States)

    Liu, Xiaozhu; Zhang, Yan; Yang, Chao; Tian, Zhihong; Li, Jianxiong

    2016-01-01

    Plants transport photoassimilates from source organs to sink tissues through the phloem translocation pathway. In the transport phloem, sugars that escape from the sieve tubes are released into the apoplasmic space between the sieve element/companion cell complex (SE/CC) and phloem parenchyma cells (PPCs) during the process of long-distance transport. The competition for sugar acquisition between SE/CC and adjoining PPCs is mediated by plasma membrane translocators. YFP-tagged AtSWEET4 protein is localized in the plasma membrane, and PromoterAtSWEET4-GUS analysis showed that AtSWEET4 is expressed in the stele of roots and veins of leaves and flowers. Overexpression of AtSWEET4 in Arabidopsis increases plant size and accumulates more glucose and fructose. By contrast, knock-down of AtSWEET4 by RNA-interference leads to small plant size, reduction in glucose and fructose contents, chlorosis in the leaf vein network, and reduction in chlorophyll content in leaves. Yeast assays demonstrated that AtSWEET4 is able to complement both fructose and glucose transport deficiency. Transgenic plants of AtSWEET4 overexpression exhibit higher freezing tolerance and support more growth of bacterium Pseudomonas syringae pv. phaseolicola NPS3121. We conclude that AtSWEET4 plays an important role in mediating sugar transport in axial tissues during plant growth and development. PMID:27102826

  13. Effect of tris(3-hydroxy-4-pyridinonate) iron(III) complexes on iron uptake and storage in soybean (Glycine max L.).

    Science.gov (United States)

    Santos, Carla S; Carvalho, Susana M P; Leite, Andreia; Moniz, Tânia; Roriz, Mariana; Rangel, António O S S; Rangel, Maria; Vasconcelos, Marta W

    2016-09-01

    Iron deficiency chlorosis (IDC) is a serious environmental problem affecting the growth of several crops in the world. The application of synthetic Fe(III) chelates is still one of the most common measures to correct IDC and the search for more effective Fe chelates remains an important issue. Herein, we propose a tris(3-hydroxy-4-pyridinonate) iron(III) complex, Fe(mpp)3, as an IDC corrector. Different morphological, biochemical and molecular parameters were assessed as a first step towards understanding its mode of action, compared with that of the commercial fertilizer FeEDDHA. Plants treated with the pyridinone iron(III) complexes were significantly greener and had increased biomass. The total Fe content was measured using ICP-OES and plants treated with pyridinone complexes accumulated about 50% more Fe than those treated with the commercial chelate. In particular, plants supplied with compound Fe(mpp)3 were able to translocate iron from the roots to the shoots and did not elicit the expression of the Fe-stress related genes FRO2 and IRT1. These results suggest that 3,4-HPO iron(III) chelates could be a potential new class of plant fertilizing agents.

  14. Arsenic toxicity in Acacia mangium willd. and mimosa Caesalpiniaefolia benth. seedlings

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    Henrique Nery Cipriani

    2013-10-01

    Full Text Available Acacia mangium and Mimosa caesalpiniaefolia are fast-growing woody fabaceous species that might be suitable for phytoremediation of arsenic (As-contaminated sites. To date, few studies on their tolerance to As toxicity have been published. Therefore, this study assessed As toxicity symptoms in A. mangium and M. caesalpiniaefolia seedlings under As stress in a greenhouse. Seedlings of Acacia mangium and M. caesalpiniaefolia were grown for 120 d in an Oxisol-sand mixture with 0, 50, 100, 200, and 400 mg kg-1 As, in four replications in four randomized blocks. The plants were assessed for visible toxicity symptoms, dry matter production, shoot/root ratio, root anatomy and As uptake. Analyses of variance and regression showed that the growth of A. mangium and M. caesalpiniaefolia was severely hindered by As, with a reduction in dry matter production of more than 80 % at the highest As rate. The root/shoot ratio increased with increasing As rates. At a rate of 400 mg kg-1 As, whitish chlorosis appeared on Mimosa caesalpiniaefolia seedlings. The root anatomy of both species was altered, resulting in cell collapse, death of root buds and accumulation of phenolic compounds. Arsenic concentration was several times greater in roots than in shoots, with more than 150 and 350 mg kg-1 in M. caesalpiniaefolia and A. mangium roots, respectively. These species could be suitable for phytostabilization of As-contaminated sites, but growth-stimulating measures should be used.

  15. Bioaccumulation, subcellular, and molecular localization and damage to physiology and ultrastructure in Nymphoides peltata (Gmel.) O. Kuntze exposed to yttrium.

    Science.gov (United States)

    Fu, Yongyang; Li, Feifei; Xu, Ting; Cai, Sanjuan; Chu, Weiyue; Qiu, Han; Sha, Sha; Cheng, Guangyu; Xu, Qinsong

    2014-02-01

    Bioaccumulation, subcellular distribution, and acute toxicity of yttrium (Y) were evaluated in Nymphoides peltata. The effects of Y concentrations of 1-5 mg L(-1) applied for 4 days were assessed by measuring changes in photosynthetic pigments, nutrient contents, enzymatic and non-enzymatic antioxidants, and ultrastructure. The accumulation of Y in subcellular fractions decreased in the order of cell wall > organelle > soluble fraction. Much more Y was located in cellulose and pectin than in other biomacromolecules. The content of some mineral elements (Mg, Ca, Fe, Mn, and Mo) increased in N. peltata, but there was an opposite effect for P and K. Meanwhile, ascorbate, and catalase activity decreased significantly for all Y concentrations. In contrast, peroxidase activity was induced, while initial rises in superoxide dismutase activity and glutathione content were followed by subsequent declines. Morphological symptoms of senescence, such as chlorosis and damage to chloroplasts and mitochondria, were observed even at the lowest Y concentration. Pigment content decreased as the Y concentration rose and the calculated EC50 and MPC of Y for N. peltata were 2 and 0.2 mg L(-1) after 4 days of exposure, respectively. The results showed that exogenous Y was highly available in water and that its high concentration in water bodies might produce harmful effects on aquatic organisms. N. peltata is proposed as a biomonitor for the assessment of metal pollution in aquatic ecosystems. PMID:24170501

  16. Virus-induced gene silencing of the RPC5-like subunit of RNA polymerase III caused pleiotropic effects in Nicotiana benthamiana.

    Science.gov (United States)

    Nemchinov, Lev G; Boutanaev, Alexander M; Postnikova, Olga A

    2016-01-01

    In eukaryotic cells, RNA polymerase III is highly conserved and transcribes housekeeping genes such as ribosomal 5S rRNA, tRNA and other small RNAs. The RPC5-like subunit is one of the 17 subunits forming RNAPIII and its exact functional roles in the transcription are poorly understood. In this work, we report that virus-induced gene silencing of transcripts encoding a putative RPC5-like subunit of the RNA Polymerase III in a model species Nicotiana benthamiana had pleiotropic effects, including but not limited to severe dwarfing appearance, chlorosis, nearly complete reduction of internodes and abnormal leaf shape. Using transcriptomic analysis, we identified genes and pathways affected by RPC5 silencing and thus presumably related to the cellular roles of the subunit as well as to the downstream cascade of reactions in response to partial loss of RNA Polymerase III function. Our results suggest that silencing of the RPC5L in N. benthamiana disrupted not only functions commonly associated with the core RNA Polymerase III transcripts, but also more diverse cellular processes, including responses to stress. We believe this is the first demonstration that activity of the RPC5 subunit is critical for proper functionality of RNA Polymerase III and normal plant development. PMID:27282827

  17. Nitrogen control of chloroplast development: Progress report

    International Nuclear Information System (INIS)

    A manifestation of nitrogen deficiency in vascular plants and algae is chlorosis, indicating that chloroplast biogenesis can be strongly restricted by direct or indirect effects of nitrogen assimilation products. To define the molecular basis of nitrogen responses we are using Chlamydomonas reinhardtii. Depending on the levels of ammonium, steady-state deficiency conditions are established such that the cellular levels of chlorophylls and xanthophylls are depressed. Chloroplasts in nitrogen-deficient cells contain appreciable levels of carbon assimilation enzyme and thylakoids with high electron transport activities. However, the light harvesting complexes are nearly absent and Photosystem I exhibits unusual characteristics. Studies of rates of protein synthesis by in vivo pulse-chase labeling and levels of RNAs encoded by the chloroplast and nuclear genomes have been initiated: the accumulation of transcripts for the nuclear light-harvesting apoproteins is dramatically altered qualitatively and quantitatively; there is no major effect on chloroplast RNAs but, in general, these are inefficiently utilized for protein synthesis until nitrogen is provided to the cultures. Supplying nitrogen results in an almost immediate release of chloroplast mRNAs from a translational arrest but the stimulation of the accumulation of nuclear transcripts for light-harvesting apoproteins does not occur until after a 1-2 hour lag

  18. Response of Bread Wheat Genotypes to Immature Embryo Culture, Callus Induction and Drought Stress

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    Parvin Elyasi

    2012-07-01

    Full Text Available In order to evaluate the response of twenty genotypes of bread wheat (Triticum aestivum L. to callus induction and in vitro drought stress. The immature embryos of wheat were used in a Completely Randomized Design (CRD with six replications for callus induction and a 20×2 factorial experiment based on CRD design with three replications was carried out for response of genotypes to in vitro drought stress at the Agricultural College of Razi University, Kermanshah, Iran during 2010-2011. Significant differences were observed among the genotypes for Callus Growth Rate (CGR, Relative Fresh Weight Growth (RFWG, Relative Growth Rate (RGR and Percentage of Callus Induction (PCI indicating the presence of genetic variability, different responses of bread wheat genotypes to callus induction and possible selection of callus induction at in vitro level using immature embryos. Mean comparison of the traits measured in callus induction showed that genotypes 1 and 6 had the highest PCI (100%. Analysis of variance for CGR, RFWG and RGR, Relative Water Content (RWC, Percent of Callus Chlorosis (PCC and Proline Content (PC exhibited significant differences among the genotypes for all the characters in the stress condition (15% PEG. Screening drought tolerant genotypes and in vitro indicators of drought tolerance using mean rank, standard deviation of ranks and biplot analysis, discriminated genotypes (6, (19 and (1 as the most drought tolerant.

  19. Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance.

    Science.gov (United States)

    Yang, Liming; Fountain, Jake C; Wang, Hui; Ni, Xinzhi; Ji, Pingsheng; Lee, Robert D; Kemerait, Robert C; Scully, Brian T; Guo, Baozhu

    2015-10-19

    Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS) than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding.

  20. Interspecific hybridization between Nicotiana repanda Willd. and N. tabacum L. through in vitro culture of irradiated ovules

    International Nuclear Information System (INIS)

    Two techniques were useful in overcoming hybrid inviability between N. repanda and N. tabacum. These techniques combine gamma-ray irradiation to pollen or to egg cells (in ovules) with in vitro culture of fertilized ovules. When in vitro culture of fertilized ovules from in situ hybridization of N. repanda x N. tabacum was combined without gamma-ray irradiation to pollen or to egg cells (in ovules), all of the resulting seedlings developed chlorosis and died. Furthermore, in the case of in situ hybridization of N. repanda x N. tabacum with gamma-ray irradiated N. tabacum pollen, no viable seeds were obtained. By using both techniques, combining gamma-ray irradiation to N. tabacum pollen or to egg cells in (N. repanda ovules) with in vitro culture of fertilized ovules, we were successful in obtaining flowering hybrid plants. Thus, it appears that it may be possible to overcome hybrid inviability to a certain extent using both the pollen irradiation technique and the egg cell irradiation technique, i.e., gamma-ray irradiation to pollen or to egg cells (in ovules) before pollination and in vitro culture of fertilized ovules. (author)

  1. The Subcellular Localization and Functional Analysis of Fibrillarin2, a Nucleolar Protein in Nicotiana benthamiana

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    Luping Zheng

    2016-01-01

    Full Text Available Nucleolar proteins play important roles in plant cytology, growth, and development. Fibrillarin2 is a nucleolar protein of Nicotiana benthamiana (N. benthamiana. Its cDNA was amplified by RT-PCR and inserted into expression vector pEarley101 labeled with yellow fluorescent protein (YFP. The fusion protein was localized in the nucleolus and Cajal body of leaf epidermal cells of N. benthamiana. The N. benthamiana fibrillarin2 (NbFib2 protein has three functional domains (i.e., glycine and arginine rich domain, RNA-binding domain, and α-helical domain and a nuclear localization signal (NLS in C-terminal. The protein 3D structure analysis predicted that NbFib2 is an α/β protein. In addition, the virus induced gene silencing (VIGS approach was used to determine the function of NbFib2. Our results showed that symptoms including growth retardation, organ deformation, chlorosis, and necrosis appeared in NbFib2-silenced N. benthamiana.

  2. Comparative analysis of differentially expressed sequence tags of sweet orange and mandarin infected with Xylella fastidiosa

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    Alessandra A. de Souza

    2007-01-01

    Full Text Available The Citrus ESTs Sequencing Project (CitEST conducted at Centro APTA Citros Sylvio Moreira/IAC has identified and catalogued ESTs representing a set of citrus genes expressed under relevant stress responses, including diseases such as citrus variegated chlorosis (CVC, caused by Xylella fastidiosa. All sweet orange (Citrus sinensis L. Osb. varieties are susceptible to X. fastidiosa. On the other hand, mandarins (C. reticulata Blanco are considered tolerant or resistant to the disease, although the bacterium can be sporadically detected within the trees, but no disease symptoms or economic losses are observed. To study their genetic responses to the presence of X. fastidiosa, we have compared EST libraries of leaf tissue of sweet orange Pêra IAC (highly susceptible cultivar to X. fastidiosa and mandarin ‘Ponkan’ (tolerant artificially infected with the bacterium. Using an in silico differential display, 172 genes were found to be significantly differentially expressed in such conditions. Sweet orange presented an increase in expression of photosynthesis related genes that could reveal a strategy to counterbalance a possible lower photosynthetic activity resulting from early effects of the bacterial colonization in affected plants. On the other hand, mandarin showed an active multi-component defense response against the bacterium similar to the non-host resistance pattern.

  3. Transcriptome Analysis of the Phytobacterium Xylella fastidiosa Growing under Xylem-Based Chemical Conditions

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    Maristela Boaceff Ciraulo

    2010-01-01

    Full Text Available Xylella fastidiosa is a xylem-limited bacterium responsible for important plant diseases, like citrus-variegated chlorosis (CVC and grapevine Pierce's disease (PD. Interestingly, in vitro growth of X. fastidiosa in chemically defined media that resemble xylem fluid has been achieved, allowing studies of metabolic processes used by xylem-dwelling bacteria to thrive in such nutrient-poor conditions. Thus, we performed microarray hybridizations to compare transcriptomes of X. fastidiosa cells grown in 3G10-R, a medium that resembles grape sap, and in Periwinkle Wilt (PW, the complex medium traditionally used to cultivate X. fastidiosa. We identified 299 transcripts modulated in response to growth in these media. Some 3G10R-overexpressed genes have been shown to be upregulated in cells directly isolated from infected plants and may be involved in plant colonization, virulence and environmental competition. In contrast, cells cultivated in PW show a metabolic switch associated with increased aerobic respiration and enhanced bacterial growth rates.

  4. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development.

  5. Effet du milieu de culture sur le microbouturage de l'olivier (Olea europeae L. cv. Picholine Marocaine

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    Abousalim A.

    2003-01-01

    Full Text Available Effect of culture medium on micropropagation of olive (Olea europeae L. cv. Moroccan Picholine. The effect of the basal media OM (Olive Medium, 1/2 MS (Murashige et Skoog with half strength macronutrients, WPM (Lloyd and McCown, 1/2 Miller (Miller with half strength macronutrients, and K&H (medium with Knop macronutrients and Heller micronutrients, supplemented with 5 mg/l Zeatine, on shoot proliferation of mature ‘Moroccan Picholine'cultivar (30 years old was investigated. OM and 1/2 MS media were the most effective at the early stages of proliferation. A microcutting percentage of up to 91,6 and 90,9 % were achieved in OM and 1/2 MS media respectively but OM was distinguished later by permitting a better shoot growth with no vitrification symptoms The highest percentages of new shoots per explant were obtained with 1/2 MS and OM media (67 and 65 % respectively. OM was the most effective for shoot height (12,42 mm followed by 1/2 MS (8,92 mm. The other tested media induced an important callus development and leaf chlorosis, and the reduction of shoot growth was noticeable.

  6. Blood meal-based compound. Good choice as iron fertilizer for organic farming.

    Science.gov (United States)

    Yunta, Felipe; Di Foggia, Michele; Bellido-Díaz, Violeta; Morales-Calderón, Manuel; Tessarin, Paola; López-Rayo, Sandra; Tinti, Anna; Kovács, Krisztina; Klencsár, Zoltán; Fodor, Ferenc; Rombolà, Adamo Domenico

    2013-05-01

    Prevention of iron chlorosis with Fe synthetic chelates is a widespread agronomical practice but implies high costs and environmental risks. Blood meal is one of the main fertilizers allowed to be used in organic farming. Through this work a novel blood meal fertilizer was audited. Measurements such as FTIR, Raman, electron paramagnetic resonance, and Mössbauer spectroscopy, UV-visible properties, stability against pH, and batch experiments were performed to characterize and assess the reactivity on soil constituents and agronomic soils. The spectroscopy findings give clear indications that Fe is in the ferric oxidation state, is hexacoordinated, and has a low-spin form suggesting a similar structure to hemin and hematin. A spectrophotometric method at 400 nm was validated to quantify blood meal concentration at low electrolyte concentrations. Batch experiments demonstrated high reactivity of blood meal fertilizer with soil constituents, mainly in the presence of calcium, where aggregation processes are predominant, and its ability to take Fe from synthetic Fe (hydr)oxides. The beneficial profile of blood meal by a providing nitrogen source together with the capability to keep the Fe bound to porphyrin organic compounds makes it a good candidate to be used as Fe fertilizer in organic farming.

  7. Hygromycin B-induced cell death is partly mediated by reactive oxygen species in rice (Oryza sativa L.).

    Science.gov (United States)

    Oung, Hui-Min; Lin, Ke-Chun; Wu, Tsung-Meng; Chandrika, Nulu Naga Prafulla; Hong, Chwan-Yang

    2015-12-01

    The aminoglycoside antibiotic hygromycin B (Hyg) inhibits prokaryotic, chloroplast and mitochondrial protein synthesis. Because of the toxic effect of Hyg on plant cells, the HPT gene, encoding hygromycin phosphotransferase, has become one of the most widely used selectable markers in plant transformation. Yet the mechanism behind Hyg-induced cell lethality in plants is not clearly understood. In this study, we aimed to decipher this mechanism. With Hyg treatment, rice calli exhibited cell death, and rice seedlings showed severe growth defects, leaf chlorosis and leaf shrinkage. Rice seedlings also exhibited severe lipid peroxidation and protein carbonylation, for oxidative stress damage at the cellular level. The production of reactive oxygen species such as O2(·-), H2O2 and OH(·) was greatly induced in rice seedlings under Hyg stress, and pre-treatment with ascorbate increased resistance to Hyg-induced toxicity indicating the existence of oxidative stress. Overexpression of mitochondrial Alternative oxidase1a gene without HPT selection marker in rice enhanced tolerance to Hyg and attenuated the degradation of protein content, whereas the rice plastidial glutathione reductase 3 mutant showed increased sensitivity to Hyg. These results demonstrate that Hyg-induced cell lethality in rice is not only due to the inhibition of protein synthesis but also mediated by oxidative stress.

  8. Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 confers enhanced salinity tolerance in chimeric sugar beet (Beta vulgaris L.).

    Science.gov (United States)

    Wu, Guo-Qiang; Feng, Rui-Jun; Wang, Suo-Min; Wang, Chun-Mei; Bao, Ai-Ke; Wei, Li; Yuan, Hui-Jun

    2015-01-01

    Salinity is one of the major abiotic stresses that limit the growth and productivity of sugar beet (Beta vulgaris L.). To improve sugar beet's salinity tolerance, the ZxNHX and ZxVP1-1 genes encoding tonoplast Na(+)/H(+) antiporter and H(+)-PPase from xerophyte Zygophyllum xanthoxylum were co-expressed by Agrobacterium tumefaciens-mediated transformation. It is showed here that co-expression of ZxNHX and ZxVP1-1 confers enhanced salinity tolerance to the transformed sugar beet plants compared with the wild-type (WT) plants. The chimeric plants grew well in the presence of high salinity (400 mM NaCl), whereas WT plants displayed chlorosis and died within 8 days. Compared to WT plants, the chimeric plants co-expressing ZxNHX and ZxVP1-1 accumulated more proline, Na(+) and K(+) in their leaves and petioles when exposed to high salinity, which caused lower solute potential, retained more water and thus subjected to lesser cell membrane damage. Interestingly, the chimeric plants accumulated higher sucrose, glucose and fructose contents in their storage roots than WT plants in the absence or presence of high salinity. Our results suggested that co-expression of ZxNHX and ZxVP1-1 improved the osmoregulatory capacity in chimeric sugar beet through increased compartmentalization of ions into the vacuoles by enhancing the activity of proton pumps and thus mitigated Na(+)-toxicity for plants.

  9. First results of investigations into causes of diseases of cultivated chamomile (Matricaria recutita L. in Germany

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    Gärber, Ute

    2016-07-01

    Full Text Available Diseases on cultivated chamomile have occurred in Germany since 2007, which have severely been affecting the crop yields. The causes of damage are very complex and have not been identified yet. Additionally to the damage in the stems caused by larvae, fungal pathogens are of relevance. Tests of the Julius Kühn-Institute first revealed that a new, not yet identified fungus is pathogenic to chamomile. Symptoms observed in infection tests like chlorosis, browning and black coloration of stems and leaflets were identical to those in the field. The fungus sporulated on diseased plant parts under the conditions of climatic chamber (20 °C to 22 °C and 12 hours of light, 122 μmol from 17 days after inoculation (dai and could be reisolated on agar plates. The identification, biology and epidemiology of the fungus as well as the specific harmful effect and interaction with other harmful factors, especially animal pests, are being studied presently in a project funded by the Agency for Renewable Resources (Fachagentur Nachwachsende Rohstoffe, FNR. The goal is to develop sustainable plant protection concepts based on the knowledge about the pathogens to enable a stable cultivation of chamomile in Germany.

  10. Effects of fluoride on germination, early growth and antioxidant enzyme activities of legume plant species Prosopis juliflora.

    Science.gov (United States)

    Saini, Poonam; Khan, Suphiya; Baunthiyal, Mamta; Sharma, Vinay

    2013-03-01

    Prosopis juliflora (Mimosoideae) is a fast growing and drought resistant tree of semi-arid region of India where fluoride (F) toxicity is a common problem. In the present investigations this species was fluoride tested to check their capacity as bioindicator plant and its efficiency to accumulate. To achieve this aim, P. juliflora seedlings grown in hydroponic culture containing different concentrations of F were analyzed for germination percentage together with some biochemical parameters viz, antioxidant enzyme activities, total chlorophyll and accumulation of F in different plant parts. After 15 days of treatment, root growth (r = -0.928, p < 0.01), shoot growth (r = -0.976, p < 0.01), vigor index (r = -0.984, p < 0.01) were in decreasing trend with increasing concentration of NaF. Both catalase (3.2 folds) and peroxidase (2.7 folds) enzymes activity increased with increase in F concentration. Plant accumulated larger portion of the F in the roots (1024.63 microg g(-1) d.wt.) followed by shoot (492.30 microg g(-1) d.wt.). As P. juliflora did not show any morphological changes (marginal and tip chlorosis of leaf portions, necrosis and together these features are referred to as leaf "tip-burn") therefore, this species may be used as suitable bioindicator species for potentially F affected areas. Further, higher accumulation of F in roots indicates that P. juliflora is a suitable species for the removal of F in phytoremediation purposes.

  11. Light affects fumonisin production in strains of Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides isolated from rice.

    Science.gov (United States)

    Matić, Slavica; Spadaro, Davide; Prelle, Ambra; Gullino, Maria Lodovica; Garibaldi, Angelo

    2013-09-16

    Three Fusarium species associated with bakanae disease of rice (Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides) were investigated for their ability to produce fumonisins (FB1 and FB2) under different light conditions, and for pathogenicity. Compared to darkness, the conditions that highly stimulated fumonisin production were yellow and green light in F. verticillioides strains; white and blue light, and light/dark alternation in F. fujikuroi and F. proliferatum strains. In general, all light conditions positively influenced fumonisin production with respect to the dark. Expression of the FUM1 gene, which is necessary for the initiation of fumonisin production, was in accordance with the fumonisin biosynthetic profile. High and low fumonisin-producing F. fujikuroi strains showed typical symptoms of bakanae disease, abundant fumonisin-producing F. verticillioides strains exhibited chlorosis and stunting of rice plants, while fumonisin-producing F. proliferatum strains were asymptomatic on rice. We report that F. fujikuroi might be an abundant fumonisin producer with levels comparable to that of F. verticillioides and F. proliferatum, highlighting the need of deeper mycotoxicological analyses on rice isolates of F. fujikuroi. Our results showed for the first time the influence of light on fumonisin production in isolates of F. fujikuroi, F. proliferatum, and F. verticillioides from rice.

  12. Development of a protocol for the identification of tospoviruses and thrips species in individual thrips.

    Science.gov (United States)

    Seepiban, Channarong; Charoenvilaisiri, Saengsoon; Kumpoosiri, Mallika; Bhunchoth, Anjana; Chatchawankanphanich, Orawan; Gajanandana, Oraprapai

    2015-09-15

    A protocol for identifying tospovirus and thrips species in an individual thrips sample was successfully developed. First, an individual thrips was soaked in an RNA stabilization solution to preserve protein and nucleic acids and ground in a carbonate buffer containing 0.2% sodium diethyldithiocarbamate. Initially, the thrips extracts were screened for tospovirus infection by dot blot analysis using antibodies to nucleocapsid (N) proteins of tospoviruses. Thrips extracts with positive results by dot blot analysis were further subjected to RNA extraction. Next, tospovirus species were identified by reverse transcription-polymerase chain reaction (RT-PCR) using species-specific primers for the N genes of four tospoviruses known to occur in Thailand, including Capsicum chlorosis virus (CaCV), Melon yellow spot virus (MYSV), Tomato necrotic ringspot virus (TNRV) and Watermelon silver mottle virus (WSMoV). The residual genomic DNA in the thrips RNA extract was used as a template to identify thrips species by PCR with species-specific primers to the internal transcribed spacer 2 regions of the rRNA of Ceratothripoides claratris, Frankliniella intonsa, Scirtothrips dorsalis and Thrips palmi. This protocol was initially validated against laboratory-reared thrips and then used to determine the occurrence of viruliferous thrips species collected from tomato, pepper, watermelon and cucumber fields in Thailand. PMID:26141731

  13. Antioxidant Status of Vigna mungo L. in Response to Sulfur Nutrition

    Directory of Open Access Journals (Sweden)

    Neelam Chandra

    2014-01-01

    Full Text Available Black gram (Vigna mungo L. var. DPU-88-31, an edible legume, was grown at 1, 2, 4, 6, and 8 meq S L−1 to study the effect of deficient and excess level of sulfur on oxidative metabolism. Plants supplied by 4 meq S L−1 showed optimum yield. Sulfur deficient plants (1 and 2 meq S L−1 showed reduction in growth and chlorosis of young leaves. Tissue sulfur and cysteine concentration was increased with increasing sulfur supply. The thresholds for critical concentration of sulfur deficiency and toxicity were 0.315% and 0.434% dry weight. Biomass and photoassimilatory pigments were decreased and carbohydrates (sugar and starch were accumulated in leaves of sulfur deficient and excess plants. Accumulation of hydrogen peroxide and thiobarbituric acid reactive substances in sulfur deficient and excess plants caused oxidative damage in plants which was also evident by the increase in the activity of superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and concentration of ascorbate and nonprotein thiols.

  14. The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa

    Science.gov (United States)

    Gouran, Hossein; Gillespie, Hyrum; Nascimento, Rafael; Chakraborty, Sandeep; Zaini, Paulo A.; Jacobson, Aaron; Phinney, Brett S.; Dolan, David; Durbin-Johnson, Blythe P.; Antonova, Elena S.; Lindow, Steven E.; Mellema, Matthew S.; Goulart, Luiz R.; Dandekar, Abhaya M.

    2016-01-01

    Pierce’s disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease “PrtA” that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa. PMID:27492542

  15. Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 confers enhanced salinity tolerance in chimeric sugar beet (Beta vulgaris L.).

    Science.gov (United States)

    Wu, Guo-Qiang; Feng, Rui-Jun; Wang, Suo-Min; Wang, Chun-Mei; Bao, Ai-Ke; Wei, Li; Yuan, Hui-Jun

    2015-01-01

    Salinity is one of the major abiotic stresses that limit the growth and productivity of sugar beet (Beta vulgaris L.). To improve sugar beet's salinity tolerance, the ZxNHX and ZxVP1-1 genes encoding tonoplast Na(+)/H(+) antiporter and H(+)-PPase from xerophyte Zygophyllum xanthoxylum were co-expressed by Agrobacterium tumefaciens-mediated transformation. It is showed here that co-expression of ZxNHX and ZxVP1-1 confers enhanced salinity tolerance to the transformed sugar beet plants compared with the wild-type (WT) plants. The chimeric plants grew well in the presence of high salinity (400 mM NaCl), whereas WT plants displayed chlorosis and died within 8 days. Compared to WT plants, the chimeric plants co-expressing ZxNHX and ZxVP1-1 accumulated more proline, Na(+) and K(+) in their leaves and petioles when exposed to high salinity, which caused lower solute potential, retained more water and thus subjected to lesser cell membrane damage. Interestingly, the chimeric plants accumulated higher sucrose, glucose and fructose contents in their storage roots than WT plants in the absence or presence of high salinity. Our results suggested that co-expression of ZxNHX and ZxVP1-1 improved the osmoregulatory capacity in chimeric sugar beet through increased compartmentalization of ions into the vacuoles by enhancing the activity of proton pumps and thus mitigated Na(+)-toxicity for plants. PMID:26284097

  16. Comparative genomic analysis of coffee-infecting Xylella fastidiosa strains isolated from Brazil.

    Science.gov (United States)

    Barbosa, Deibs; Alencar, Valquíria Campos; Santos, Daiene Souza; de Freitas Oliveira, Ana Cláudia; de Souza, Alessandra A; Coletta-Filho, Helvecio D; de Oliveira, Regina Souza; Nunes, Luiz R

    2015-05-01

    Strains of Xylella fastidiosa constitute a complex group of bacteria that develop within the xylem of many plant hosts, causing diseases of significant economic importance, such as Pierce's disease in North American grapevines and citrus variegated chlorosis in Brazil. X. fastidiosa has also been obtained from other host plants, in direct correlation with the development of diseases, as in the case of coffee leaf scorch (CLS)--a disease with potential to cause severe economic losses to the Brazilian coffee industry. This paper describes a thorough genomic characterization of coffee-infecting X. fastidiosa strains, initially performed through a microarray-based approach, which demonstrated that CLS strains could be subdivided in two phylogenetically distinct subgroups. Whole-genomic sequencing of two of these bacteria (one from each subgroup) allowed identification of ORFs and horizontally transferred elements (HTEs) that were specific to CLS-related X. fastidiosa strains. Such analyses confirmed the size and importance of HTEs as major mediators of chromosomal evolution amongst these bacteria, and allowed identification of differences in gene content, after comparisons were made with previously sequenced X. fastidiosa strains, isolated from alternative hosts. Although direct experimentation still needs to be performed to elucidate the biological consequences associated with such differences, it was interesting to verify that CLS-related bacteria display variations in genes that produce toxins, as well as surface-related factors (such as fimbrial adhesins and LPS) that have been shown to be involved with recognition of specific host factors in different pathogenic bacteria. PMID:25737482

  17. Phytostabilization Potential of Yard long bean in Removing Cadmium from Soil

    Directory of Open Access Journals (Sweden)

    Deivanai S.

    2014-05-01

    Full Text Available The effect of cadmium (Cd on growth, physiology, distribution and tolerance was examined in root, shoot and leaves of yard-long bean (Vigna unguiculata subsp. sesquipedalis L.. The seeds were grown in pot culture under laboratory conditions for 60 days in Ferriera and Davis nutrient solution with three different concentrations (0.5, 1.0 and 2.0 mM of cadmium. Cd toxicity was evident from chlorosis in young leaves and increased concentrations of Cd brought significant negative effects on plant growth, photosynthetic rate and protein biosynthesis. Translocation of Cd was found to be more in roots than the above ground parts and the accumulation was in the order of root > shoot > leaf. Low root to shoot translocation of Cd makes the crop ideal for phytostabilization. Relatively high metal tolerance index obtained in the study indicated that the crop has greater tolerance to increase Cd exposure, though accumulation of Cd had altered thickness of root and root biomass. Owing to the crop’s adaptability to high temperature, drought conditions and ability to retain Cd in roots makes it a promising candidate for phytostabilization of soil contaminated by Cd.

  18. Influence Of Iron Sources In The Nutrient Medium On In Vitro Shoot Multiplication And Rooting Of Magnolia And Cherry Plum

    Directory of Open Access Journals (Sweden)

    Sokolov Rosen S.

    2015-12-01

    Full Text Available In this study, the effects of compounds providing Fe in chelated (NaFeEDTA and Fe(IIIAC and non-chelated (FeSO4·7H2O forms as components of culture media, on in vitro shoot multiplication and rooting of Magnolia soulangeana ‘Alexandrina’, Magnolia grandiflora and Prunus cerasifera ‘Nigra’ were comparatively evaluated. Each of the tested chemicals was used as a single Fe source in the basal salt medium. In the stages of shoot multiplication and rooting plant response was scored by biometrical indices (number of shoots, leaves and roots, shoot and root length, percent of rooted plants and root hairs. The occurrence of physiological disorders was estimated by visual observations. In presence of FeSO4, symptoms of chlorosis, hyperhy-dricity, early senescence and specific morphology of roots, suggesting Fe deficiency, were observed. These deteriorations were entirely prevented at the application of Fe chelates of which, in this experimental systems, Fe(IIIAC was tested for the first time. The addition of Fe(IIIAC positively affected the plant quality to extent comparable to that of NaFeEDTA. The obtained data suggest that both applied Fe chelates are more appropriate than non-chelated Fe form and can be alternatively used in the optimization of nutrient media for micropropagation of Magnolia and Prunus cerasifera genotypes.

  19. Investigation on Yield, Fruit Quality and Plant Characteristics of Some Local, European and American Strawberry Varieties and their Hybrids

    Directory of Open Access Journals (Sweden)

    Müge Özuygur

    2006-12-01

    Full Text Available This study was conducted in 2003-2004 and 2004-2005 growing periods. Our local cultivar “Osmanlı”, European and American cultivars: “Camarosa”, “Sweet Charlie”, “Gaviota”, “Maya”, “Paros”, “Cilady”, “Cigoulette”, “Marlate”, “Sophie”, “Ciloe”, “Diamante” and “Camarosa” , hybrids from Italian breeding program: “92/340/3”, “MT/j24/2”, “MT99/20/1”, “MT99/121/9”, “MT99/163/14”, “MT99/163/19”and “MT99/163/22”, and hybrids from Turkish breeding program: “3”, “5”, “6”, “8”, “11”, “13” and “17” were used as plant material. Average yield per plant (g/plant, fruit weight (g and some phenological plant characteristics such as plant growth shape, plant density, plant vigour, leaf size, leaf softness, beginning of flowering time and response to Fe chlorosis of experimental strawberry genotypes were evaluated. Hybrids MT J24/2 and MT 99/163/22 were found to be very satisfactory in terms of average yield/plant, and fruit weight respectively.

  20. Synthesis and characterization of γ-ferric oxide nanoparticles and their effect on Solanum lycopersicum.

    Science.gov (United States)

    Pavani, Tambur; Rao, K Venkateswara; Chakra, Ch Shilpa; Prabhu, Y T

    2016-05-01

    γ-Ferric oxide nanoparticles are synthesized through modern and facile ayurvedic route followed by normal and special purification steps, which are both cost-effective and eco-friendly. These synthesized γ-ferric oxide nanoparticles were applied on Solanum lycopersicum to search the effect on chlorophyll content. This process involves multiple filtration and calcination steps. The synthesized samples were analyzed by X-ray diffraction (XRD), UV-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and particle size analysis (PSA) to identify the purification step's influence on the structural, optical, morphological, magnetic, and particle size properties of ferric oxide nanoparticles (γ-phase). X-ray diffraction has revealed that ferric oxide nanoparticles have rhombohedral structure of α-phase (hematite) in initial purification process later transformed into cubic structure γ-phase (maghemite). UV-vis spectroscopy analysis has clearly shown that by repetitive purification steps, λmax has increased from 230 to 340 nm. TEM result has an intercorrelation with XRD results. γ-Ferric oxide nanoparticles were tested on Solanum lycopersicum (tomato seeds). The changes in the contents of chlorophyll a, chlorophyll b, and total carotene were studied using spectral measurements at two different dosages-0.5 and 2 M. As a result, at 0.5-M concentration, magnetic nanoparticles exhibit fruitful results by increasing the crop yield and being more resistant to chlorosis. PMID:26296507

  1. Molecular and morphological identification of mealybug species (Hemiptera: Pseudococcidae in Brazilian vineyards.

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    Vitor C Pacheco da Silva

    Full Text Available Mealybugs (Hemiptera: Pseudococcidae are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell, Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley, Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso, Pseudococcus viburni (Signoret, Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret. Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species.

  2. Effects of an experimental oil spill (bunker on seedling survival and growth rate of Laguncularia racemosa (Combretaceae

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    Emanoela Nardes

    2013-03-01

    Full Text Available The effects of bunker oil on survival and growth rate of Laguncularia racemosa were tested using 60 seedlings planted in small plastic bags (experimental unit. One of the six treatments was randomly assigned to each bag: 0 mL (control, 10 mL, 20 mL, 30 mL, 40 mL e 50 mL of bunker oil spilled in each bag. The experiment was monitored weekly for 20 weeks. The results were analyzed by repeated measure ANOVA and linear regression. In the first seven weeks, we observed chlorosis, loss of leafs and death rate significantly superior to plants of all treatments compared to the control group. Persistent effects like reduction of stem growth and leaf production was proportional to the initial oil concentration. The plants from control and 10 mL treatments were significantly superior to all remaining treatments in height, leaf number and healthy level. Results indicated that L. racemosa seedlings suffer both lethal and sublethal effects from exposition to bunker oil exposure.

  3. Molecular and morphological identification of mealybug species (Hemiptera: Pseudococcidae) in Brazilian vineyards.

    Science.gov (United States)

    Pacheco da Silva, Vitor C; Bertin, Aline; Blin, Aurélie; Germain, Jean-François; Bernardi, Daniel; Rignol, Guylène; Botton, Marcos; Malausa, Thibaut

    2014-01-01

    Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell), Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley), Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso), Pseudococcus viburni (Signoret), Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn) and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret). Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species.

  4. Ecotoxicological experiences on Lemna minor test system.

    Science.gov (United States)

    Szamosi-Hernádi, D; Oláh, B; Gáty, S; Pap, L

    2000-07-01

    Are plants generally less sensitive to toxicity than aquatic animals as indicated by some authors (1)? The use of phytotoxicity (higher plant) tests as a part of ecotoxicology is relatively underdeveloped. The objective of this study was to compare the results of the OECD Lemna Growth Inhibition Test with other mainly used test systems. Three toxicants were tested applying the Alga Growth Inhibition Test (Seleneastrum capricornutum), the Daphnia Immobilization Test (Daphnia magna) and the MICROTOX-test (Photobacterium phosphoreum). Duckweed plants were found to be sensitive to the chemicals tested, with nearly 100% inhibition of frond production occurring in the highest concentrations. The plants in some samples showed lesions (break up of the colony structure) and loss of green pigments (chlorosis), others showed localized dead tissues (necrosis). In addition to the morphological deviations (appearance) there is a wide range of characteristics to be observed on the test plants: number of fronds, number of plants, biomass, dry weight, mortality, CO2 and O2 exchange, concentration of chlorophyll a and chlorophyll b. It is consistent that the number of fronds is slightly more sensitive than or the same as the number of plants and that the biomass tend to be somewhat more tolerant than those for the number of plants (2). Applying the simplest way of observation, changes in the frond number were recorded. As Lemna minor show a characteristical sensitivity to the different kind of chemicals, it is a promising indicator of aquatic toxicity. PMID:10943492

  5. The complex biogeography of the plant pathogen Xylella fastidiosa: genetic evidence of introductions and Subspecific introgression in Central America.

    Directory of Open Access Journals (Sweden)

    Leonard Nunney

    Full Text Available The bacterium Xylella fastidiosa is a plant pathogen with a history of economically damaging introductions of subspecies to regions where its other subspecies are native. Genetic evidence is presented demonstrating the introduction of two new taxa into Central America and their introgression into the native subspecies, X. fastidiosa subsp. fastidiosa. The data are from 10 genetic outliers detected by multilocus sequence typing (MLST of isolates from Costa Rica. Six (five from oleander, one from coffee defined a new sequence type (ST53 that carried alleles at six of the eight loci sequenced (five of the seven MLST loci diagnostic of the South American subspecies Xylella fastidiosa subsp. pauca which causes two economically damaging plant diseases, citrus variegated chlorosis and coffee leaf scorch. The two remaining loci of ST53 carried alleles from what appears to be a new South American form of X. fastidiosa. Four isolates, classified as X. fastidiosa subsp. fastidiosa, showed a low level of introgression of non-native DNA. One grapevine isolate showed introgression of an allele from X. fastidiosa subsp. pauca while the other three (from citrus and coffee showed introgression of an allele with similar ancestry to the alleles of unknown origin in ST53. The presence of X. fastidiosa subsp. pauca in Central America is troubling given its disease potential, and establishes another route for the introduction of this economically damaging subspecies into the US or elsewhere, a threat potentially compounded by the presence of a previously unknown form of X. fastidiosa.

  6. The MqsRA Toxin-Antitoxin System from Xylella fastidiosa Plays a Key Role in Bacterial Fitness, Pathogenicity, and Persister Cell Formation.

    Science.gov (United States)

    Merfa, Marcus V; Niza, Bárbara; Takita, Marco A; De Souza, Alessandra A

    2016-01-01

    Through the formation of persister cells, bacteria exhibit tolerance to multidrug and other environmental stresses without undergoing genetic changes. The toxin-antitoxin (TA) systems are involved in the formation of persister cells because they are able to induce cell dormancy. Among the TA systems, the MqsRA system has been observed to be highly induced in persister cells of Xylella fastidiosa (causal agent of citrus variegated chlorosis-CVC) activated by copper stress, and has been described in Escherichia coli as related to the formation of persister cells and biofilms. Thus, we evaluated the role of this TA system in X. fastidiosa by overexpressing the MqsR toxin, and verified that the toxin positively regulated biofilm formation and negatively cell movement, resulting in reduced pathogenicity in citrus plants. The overexpression of MqsR also increased the formation of persister cells under copper stress. Analysis of the gene and protein expression showed that this system likely has an autoregulation mechanism to express the toxin and antitoxin in the most beneficial ratio for the cell to oppose stress. Our results suggest that this TA system plays a key role in the adaptation and survival of X. fastidiosa and reveal new insights into the physiology of phytopathogen-host interactions. PMID:27375608

  7. VapD in Xylella fastidiosa Is a Thermostable Protein with Ribonuclease Activity.

    Directory of Open Access Journals (Sweden)

    Juliano S Mendes

    Full Text Available Xylella fastidiosa strain 9a5c is a gram-negative phytopathogen that is the causal agent of citrus variegated chlorosis (CVC, a disease that is responsible for economic losses in Brazilian agriculture. The most well-known mechanism of pathogenicity for this bacterial pathogen is xylem vessel occlusion, which results from bacterial movement and the formation of biofilms. The molecular mechanisms underlying the virulence caused by biofilm formation are unknown. Here, we provide evidence showing that virulence-associated protein D in X. fastidiosa (Xf-VapD is a thermostable protein with ribonuclease activity. Moreover, protein expression analyses in two X. fastidiosa strains, including virulent (Xf9a5c and nonpathogenic (XfJ1a12 strains, showed that Xf-VapD was expressed during all phases of development in both strains and that increased expression was observed in Xf9a5c during biofilm growth. This study is an important step toward characterizing and improving our understanding of the biological significance of Xf-VapD and its potential functions in the CVC pathosystem.

  8. VapD in Xylella fastidiosa Is a Thermostable Protein with Ribonuclease Activity.

    Science.gov (United States)

    Mendes, Juliano S; Santiago, André da S; Toledo, Marcelo A S; Rosselli-Murai, Luciana K; Favaro, Marianna T P; Santos, Clelton A; Horta, Maria Augusta C; Crucello, Aline; Beloti, Lilian L; Romero, Fabian; Tasic, Ljubica; de Souza, Alessandra A; de Souza, Anete P

    2015-01-01

    Xylella fastidiosa strain 9a5c is a gram-negative phytopathogen that is the causal agent of citrus variegated chlorosis (CVC), a disease that is responsible for economic losses in Brazilian agriculture. The most well-known mechanism of pathogenicity for this bacterial pathogen is xylem vessel occlusion, which results from bacterial movement and the formation of biofilms. The molecular mechanisms underlying the virulence caused by biofilm formation are unknown. Here, we provide evidence showing that virulence-associated protein D in X. fastidiosa (Xf-VapD) is a thermostable protein with ribonuclease activity. Moreover, protein expression analyses in two X. fastidiosa strains, including virulent (Xf9a5c) and nonpathogenic (XfJ1a12) strains, showed that Xf-VapD was expressed during all phases of development in both strains and that increased expression was observed in Xf9a5c during biofilm growth. This study is an important step toward characterizing and improving our understanding of the biological significance of Xf-VapD and its potential functions in the CVC pathosystem. PMID:26694028

  9. The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa.

    Science.gov (United States)

    Gouran, Hossein; Gillespie, Hyrum; Nascimento, Rafael; Chakraborty, Sandeep; Zaini, Paulo A; Jacobson, Aaron; Phinney, Brett S; Dolan, David; Durbin-Johnson, Blythe P; Antonova, Elena S; Lindow, Steven E; Mellema, Matthew S; Goulart, Luiz R; Dandekar, Abhaya M

    2016-01-01

    Pierce's disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease "PrtA" that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa. PMID:27492542

  10. The complex biogeography of the plant pathogen Xylella fastidiosa: genetic evidence of introductions and Subspecific introgression in Central America.

    Science.gov (United States)

    Nunney, Leonard; Ortiz, Beatriz; Russell, Stephanie A; Ruiz Sánchez, Rebeca; Stouthamer, Richard

    2014-01-01

    The bacterium Xylella fastidiosa is a plant pathogen with a history of economically damaging introductions of subspecies to regions where its other subspecies are native. Genetic evidence is presented demonstrating the introduction of two new taxa into Central America and their introgression into the native subspecies, X. fastidiosa subsp. fastidiosa. The data are from 10 genetic outliers detected by multilocus sequence typing (MLST) of isolates from Costa Rica. Six (five from oleander, one from coffee) defined a new sequence type (ST53) that carried alleles at six of the eight loci sequenced (five of the seven MLST loci) diagnostic of the South American subspecies Xylella fastidiosa subsp. pauca which causes two economically damaging plant diseases, citrus variegated chlorosis and coffee leaf scorch. The two remaining loci of ST53 carried alleles from what appears to be a new South American form of X. fastidiosa. Four isolates, classified as X. fastidiosa subsp. fastidiosa, showed a low level of introgression of non-native DNA. One grapevine isolate showed introgression of an allele from X. fastidiosa subsp. pauca while the other three (from citrus and coffee) showed introgression of an allele with similar ancestry to the alleles of unknown origin in ST53. The presence of X. fastidiosa subsp. pauca in Central America is troubling given its disease potential, and establishes another route for the introduction of this economically damaging subspecies into the US or elsewhere, a threat potentially compounded by the presence of a previously unknown form of X. fastidiosa. PMID:25379725

  11. Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence.

    Science.gov (United States)

    Caserta, R; Picchi, S C; Takita, M A; Tomaz, J P; Pereira, W E L; Machado, M A; Ionescu, M; Lindow, S; De Souza, A A

    2014-11-01

    Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants. PMID:25099341

  12. The genome sequence of the plant pathogen Xylella fastidiosa. The Xylella fastidiosa Consortium of the Organization for Nucleotide Sequencing and Analysis.

    Science.gov (United States)

    Simpson, A J; Reinach, F C; Arruda, P; Abreu, F A; Acencio, M; Alvarenga, R; Alves, L M; Araya, J E; Baia, G S; Baptista, C S; Barros, M H; Bonaccorsi, E D; Bordin, S; Bové, J M; Briones, M R; Bueno, M R; Camargo, A A; Camargo, L E; Carraro, D M; Carrer, H; Colauto, N B; Colombo, C; Costa, F F; Costa, M C; Costa-Neto, C M; Coutinho, L L; Cristofani, M; Dias-Neto, E; Docena, C; El-Dorry, H; Facincani, A P; Ferreira, A J; Ferreira, V C; Ferro, J A; Fraga, J S; França, S C; Franco, M C; Frohme, M; Furlan, L R; Garnier, M; Goldman, G H; Goldman, M H; Gomes, S L; Gruber, A; Ho, P L; Hoheisel, J D; Junqueira, M L; Kemper, E L; Kitajima, J P; Krieger, J E; Kuramae, E E; Laigret, F; Lambais, M R; Leite, L C; Lemos, E G; Lemos, M V; Lopes, S A; Lopes, C R; Machado, J A; Machado, M A; Madeira, A M; Madeira, H M; Marino, C L; Marques, M V; Martins, E A; Martins, E M; Matsukuma, A Y; Menck, C F; Miracca, E C; Miyaki, C Y; Monteriro-Vitorello, C B; Moon, D H; Nagai, M A; Nascimento, A L; Netto, L E; Nhani, A; Nobrega, F G; Nunes, L R; Oliveira, M A; de Oliveira, M C; de Oliveira, R C; Palmieri, D A; Paris, A; Peixoto, B R; Pereira, G A; Pereira, H A; Pesquero, J B; Quaggio, R B; Roberto, P G; Rodrigues, V; de M Rosa, A J; de Rosa, V E; de Sá, R G; Santelli, R V; Sawasaki, H E; da Silva, A C; da Silva, A M; da Silva, F R; da Silva, W A; da Silveira, J F; Silvestri, M L; Siqueira, W J; de Souza, A A; de Souza, A P; Terenzi, M F; Truffi, D; Tsai, S M; Tsuhako, M H; Vallada, H; Van Sluys, M A; Verjovski-Almeida, S; Vettore, A L; Zago, M A; Zatz, M; Meidanis, J; Setubal, J C

    2000-07-13

    Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and two plasmids of 51,158 bp and 1,285 bp. We can assign putative functions to 47% of the 2,904 predicted coding regions. Efficient metabolic functions are predicted, with sugars as the principal energy and carbon source, supporting existence in the nutrient-poor xylem sap. The mechanisms associated with pathogenicity and virulence involve toxins, antibiotics and ion sequestration systems, as well as bacterium-bacterium and bacterium-host interactions mediated by a range of proteins. Orthologues of some of these proteins have only been identified in animal and human pathogens; their presence in X. fastidiosa indicates that the molecular basis for bacterial pathogenicity is both conserved and independent of host. At least 83 genes are bacteriophage-derived and include virulence-associated genes from other bacteria, providing direct evidence of phage-mediated horizontal gene transfer. PMID:10910347

  13. Legal considerations involving chemical control of iron and other deficiencies in plants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A; Samman, Y. S.

    1981-01-01

    Four cases of lawsuits involving use of chelating agents in plant nutrition are discussed. Three of them involved use of iron. One concerned addition of FeDTPA to nursery trees in containers. One case involved foliar application of FeHEDTA to potatoes in July by airplane. Another case not involving iron chelate was with ZnEDTA and MnEDTA with Fe as FeSO/sub 4/ later as a foliar spray. The Zn and MnEDTA were applied as a band 8 inches (20 cm) on both sides of nursery tree rows just as the buds that had been placed in the fall began growing in the spring. In the fourth case, many tomato transplants died when the transplanting was done with about 120 ml per plant of transplant solution containing besides N, P and K, about 19 mg Zn as ZnEDTA, 14 mg Mn as MnEDTA and 7 mg Fe as FeHEDTA. Cases such as these will probably discourage use of chelating agents in plant nutrition even if the chelating agents were not the damaging agent. Not enough developmental work was done on the potential toxicities from metal chelates. This trend to lawsuits makes it even more important to solve iron chlorosis problems via plant breeding.

  14. Laser-induced fluorescence of green plants. I - A technique for the remote detection of plant stress and species differentiation

    Science.gov (United States)

    Chappelle, E. W.; Wood, F. M., Jr.; Mcmurtrey, J. E., III; Newcomb, W. W.

    1984-01-01

    The laser-induced fluorescence (LIF) of green plants was evaluated as a means of remotely detecting plant stress and determining plant type. Corn and soybeans were used as representatives of monocots and dicots, respectively, in these studies. The fluorescence spectra of several plant pigments was excited with a nitrogen laser emitting at 337 nm. Intact leaves from corn and soybeans also fluoresced using the nitrogen laser. The two plant species exhibited fluorescence spectra which had three maxima in common at 440, 690, and 740 nm. However, the relative intensities of these maxima were distinctly different for the two species. Soybeans had an additional slight maxima at 525 nm. Potassium deficiency in corn caused an increase in fluorescence at 690 and 740 nm. Simulated water stress in soybeans resulted in increased fluorescence at 440, 525, 690, and 740 nm. The inhibition of photosynthesis in soybeans by 3-(3-4-dichlorophenyl)-1-1-dimethyl urea (DCMU) gave incresed fluorescence primarily at 690 and 740 nm. Chlorosis as occurring in senescent soybean leaves caused a decrease in fluorescence at 690 and 740 nm. These studies indicate that LIF measurements of plants offer the potential for remotely detecting certain types of stress condition and also for differentiating plant species.

  15. Photosynthetic efficiency of Pedunculate oak seedlings under simulated water stress

    Directory of Open Access Journals (Sweden)

    Popović Zorica

    2010-01-01

    Full Text Available Photosynthetic performance of seedlings of Quercus robur exposed to short-term water stress in the laboratory conditions was assessed through the method of induced fluorometry. The substrate for seedlings was clayey loam, with the dominant texture fraction made of silt, followed by clay and fine sand, with total porosity 68.2%. Seedlings were separated in two groups: control (C (soil water regime in pots was maintained at the level of field water capacity and treated (water-stressed, WS (soil water regime was maintained in the range of wilting point and lentocapillary capacity. The photosynthetic efficiency was 0.642±0.25 and 0.522±0.024 (WS and C, respectively, which was mostly due to transplantation disturbances and sporadic leaf chlorosis. During the experiment Fv/Fm decreased in both groups (0.551±0.0100 and 0.427±0.018 in C and WS, respectively. Our results showed significant differences between stressed and control group, in regard to both observed parameters (Fv/Fm and T½. Photosynthetic efficiency of pedunculate oak seedlings was significantly affected by short-term water stress, but to a lesser extent than by sufficient watering.

  16. Co-operative intermolecular kinetics of 2-oxoglutarate dependent dioxygenases may be essential for system-level regulation of plant cell physiology

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    Siddhartha eKundu

    2015-07-01

    Full Text Available Chlorosis, a common manifestation of Fe-deficiency in plants occurs in soils with an alkaline pH and/or a high concentration of calcium carbonate (calcareous, and is an important cause of depressed yield. The core premise of this work is the notion that the response to waning ferrous iron in the cytosol of graminaceous root cells is a well orchestrated pathophysiological event, wherein the principal co-ordinator is not restricted to a single protein, but is an assortment of enzymes. The 2OG-dependent sequences comprise members present in all major kingdoms of life, and catalyze the release of carbon dioxide and succinic acid from 2-oxoglutarate, and the hydroxylation of a substrate molecule. This generic reaction is, in most cases accompanied by a specialized conversion of the product. Here, I present a model of iron deficiency sensing and response actuation in the root cells of graminaceous crops. This hypothesis is centered on the rationale that, iron is an essential co-factor for the catalytic process, and therefore, declining cytosolic levels of this micronutrient could trigger compensatory measures. Regression models of empirically available kinetic data for iron and alpha-ketoglutarate were formulated, analysed, and compared. The results, when viewed in the context of the superfamily responding as a unit to this abiotic stressor, suggest that the 2OG-sequences can indeed, work together to mitigate the effects of this noxious stimulus.

  17. Effects of cadmium and lead concentrations and arbuscular mycorrhiza on growth, flowering and heavy metal accumulation in scarlet sage (Salvia splendens sello 'torreador'

    Directory of Open Access Journals (Sweden)

    Joanna Nowak

    2012-12-01

    Full Text Available The objective of this research was to examine the influence of Cd (0, 10, 20, 40 mg Cd·dm-3 and Pb (0, 10, 100, 200 mg Pb·dm-3 in growing substrate and mycorrhizal colonization of root system on growth, flowering, Cd and Pb accumulation in scarlet sage shoots. Both Cd and Pb had a negative effect on mycorrhizal colonization of scarlet sage roots. The effect of Cd and Pb on the growth of scarlet sage was negligible. Cd at 40 mg·dm-3 lowered the number of inflorescences and caused slight chlorosis of the lowermost leaves. Pb at 200 mg·dm-3 caused drying of the lowermost leaves. Both heavy metals accelerated flowering of non-mycorrhizal plants, independently of the concentration in growing media. Cd and Pb contents in scarlet sage shoots increased with the increasing content of these heavy metals in growing substrate in both non-mycorrhizal and mycorrhizal plants. Mycorrhization decreased the growth of scarlet sage and increased the accumulation of Cd and Pb in shoots of plants grown in media strongly polluted with heavy metals.

  18. Transcriptomic analysis of Ustilago maydis infecting Arabidopsis reveals important aspects of the fungus pathogenic mechanisms.

    Science.gov (United States)

    Martínez-Soto, Domingo; Robledo-Briones, Angélica M; Estrada-Luna, Andrés A; Ruiz-Herrera, José

    2013-08-01

    Transcriptomic and biochemical analyses of the experimental pathosystem constituted by Ustilago maydis and Arabidopsis thaliana were performed. Haploid or diploid strains of U. maydis inoculated in A. thaliana plantlets grew on the surface and within the plant tissues in the form of mycelium, inducing chlorosis, anthocyanin formation, malformations, necrosis and adventitious roots development, but not teliospores. Symptoms were more severe in plants inoculated with the haploid strain which grew more vigorously than the diploid strain. RNA extracted at different times post-infection was used for hybridization of one-channel microarrays that were analyzed focusing on the fungal genes involved in the general pathogenic process, biogenesis of the fungal cell wall and the secretome. In total, 3,537 and 3,299 genes were differentially expressed in the haploid and diploid strains, respectively. Differentially expressed genes were related to different functional categories and many of them showed a similar regulation occurring in U. maydis infecting maize. Our data suggest that the haploid strain behaves as a necrotrophic pathogen, whereas the diploid behaves as a biotrophic pathogen. The results obtained are evidence of the usefulness of the U. maydis-A. thaliana pathosystem for the analysis of the pathogenic mechanisms of U. maydis.

  19. Effects of cadmium and arsenic on Pteris vittata under hydroponic conditions.

    Science.gov (United States)

    Drava, Giuliana; Roccotiello, Enrica; Minganti, Vincenzo; Manfredi, Alice; Cornara, Laura

    2012-06-01

    Pteris vittata is known to hyperaccumulate arsenic, and a large number of studies on this fern species can be found in the literature aimed at evaluating its behavior when coexposed to other toxic elements. In the present study, P. vittata was treated with different concentrations of As and/or Cd in a hydroponic system, that is, under complete bioavailability of the elements, with the objective of investigating the effects of these two elements and their interactions. The response of the plant was evaluated by measuring As, Cd, P, and Ca concentrations in different parts of the plant. Moreover, the symptoms of phytotoxicity were assessed in terms of biomass reduction and loss of photosynthetic efficiency related to necrosis of pinnae. The concentrations of As and Cd measured in the fronds and the root system were significantly dependent on the treatment, whereas P and Ca concentrations were not affected. Interaction effects between As and Cd were observed, with maximum toxicity symptoms after treatment with both elements. This could affect the potential use of this fern for phytoremediation. Although As treatment produced a significant effect on leaves (e.g., chlorosis and necrosis), Cd treatment produced a stronger negative impact on plant health, reducing significantly the biomass and photosynthetic efficiency.

  20. Phytoremediation of arsenic by Trapa natans in a hydroponic system.

    Science.gov (United States)

    Baruah, Sangita; Borgohain, Jayasree; Sarma, K P

    2014-05-01

    Phytoremediation of arsenic (As) by water chestnut (Trapa natans) in a hydroponic system was studied. Plants were grown at two concentrations of arsenic, 1.28 mg/L and 10.80 mg/L, in a single metal solution. Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) confirmed highest arsenic concentration in the roots, followed by shoots and leaves. SEM-EDX also confirmed internalization of arsenic in T. natans and the damage caused due to arsenic exposure. Fourier Transform Infra Red Spectroscopy (FT-IRS) indicated that the binding characteristics of the arsenic ions involved the hydroxyl, amide, amino, and thiol groups in the biomass. Chlorophyll concentration decreased with increasing metal concentration and duration of exposure, but proline content increases with increasing concentration in the plant. Morphological changes were studied on the 3rd, 5th and 7th day. Unhealthy growth and chlorosis were found to be related with arsenic toxicity. From the above studies it is clear that T. natans can be used successfully for the removal of arsenic ions by a phytoremediation process.

  1. First report of Geosmithia langdonii and Geosmithia spp. isolated from a decaying elm (Ulmus minor in Geneva, Switzerland

    Directory of Open Access Journals (Sweden)

    Hänzi Martine

    2016-06-01

    Full Text Available The mortality of a young elm Ulmus minor in 2014 in Geneva prompted a search for the microorganisms potentially involved. Symptoms included foliar chlorosis and wilting followed by defoliation of branches. Wood symptoms included a brown streaking of sap wood and brown stains in trunk and branches. The comparison of the resulting ITS rDNA sequences to the NCBI Nucleotide database allowed to identify 10 different organisms. The genus Geosmithia represented 48% of the isolates belonging to three species: Geosmithia langdonii (7 isolates and 2 unknown morphologically and genetically different Geosmithia sp. 1 and sp. 2 (4 isolates. Geosmithia species are very little known ascomycetes, which have been recently shown to be opportunistic pathogens on broadleaved trees and conifers, living as saprobes in galleries of many bark beetle species. In the case described here, Geosmithia langdonii, and the unknown Geosmithia species were found in symptomatic wood while bark beetle galleries were found in close regions of the symptomatic wood. Geosmithia langdonii was the major fungus retrieved from the symptomatic wood and could have contributed, along with other identified fungal species, to a pathogenic complex producing symptoms similar to the ones of the Dutch Elm Disease and led to the dieback of this elm tree. Geosmithia langdonii and 2 yet unknown Geosmithia species (sp. 1 and sp. 2, different from any other reported Geosmithia species are reported from an elm tree in Switzerland for the first time.

  2. Investigating physiological characteristics of mint in the Raft aquaponic system and perlite medium

    Directory of Open Access Journals (Sweden)

    H. R. Roosta

    2010-12-01

    Full Text Available Aquaponic is a combination of fish and plant cultivated in recirculating systems. Fish culture in closed recirculating systems causes organic waste accumulation in the system. If these metabolites are used for plant nutrition, they are not mere waste, but have economical value and however benefit the fish production systems. Most aquaponic systems are designed as perlite-filled media, thin layer of nutrient solution, or Raft system. Photosynthesis parameters and water relations are good indexes for recognition of healthy plants and are used as tools for studying physiological conditions of plants. In this experiment, mint plants were cultivated in Raft aquaponic system and perlite medium. In Raft system, plant roots were suspending in water and absorbed water from pot bottom. Whereas in perlite system, roots were in the perlite medium and irrigation water was applied from top of the pots. The plants grown in Raft system showed mineral elements’ deficiency as leaf chlorosis. Photosynthesis and water parameters analysis showed that photosynthesis rate, stomatal conductance, transpiration, mezophyll efficiency, water use efficiency and photosynthesis active radiation were higher in the plants grown in perlite than in raft aquaponic system. On the other hand, stomatal conductance, leaf temperature and sub-stomatal CO2 were higher in the raft aquaponic system than perlite medium. Thus, due to better physiological conditions of mint plants, perlite medium might yield better results compared to raft aquaponic system.

  3. Relationship between heavy fuel oil phytotoxicity and polycyclic aromatic hydrocarbon contamination in Salicornia fragilis

    Energy Technology Data Exchange (ETDEWEB)

    Meudec, Anna; Poupart, Nathalie; Deslandes, Eric [Laboratoire d' Ecophysiologie et de Biotechnologie des Halophytes et des Algues Marines (LEBHAM), UPRES EA 3877, Institut Universitaire Europeen de la Mer, Universite de Bretagne Occidentale, Technopole Brest Iroise, Place Nicolas Copernic, 29280 Plouzane (France); Dussauze, Jacques [Institut Departemental d' analyses, de conseil et d' expertise en Hygiene alimentaire, Eau et environnement et Sante Animale (IDHESA), 120 rue Alexis de Rochon, BP52, 29280 Plouzane (France)

    2007-08-01

    Greenhouse experiments were carried out to study the effects of heavy fuel oil contamination on the growth and the development of Salicornia fragilis Ball and Tutin, a salt-marsh edible species. Plants were sampled in spring at the 'Aber du Conquet' (Finistere, France), and artificially exposed by coating shoot sections with N 6 fuel oil or by mixing it in their substratum. The impact of petroleum on plant development was followed by phytotoxicity assessments and PAH shoots assays. The plants exhibited visual symptoms of stress, i.e. chlorosis, yellowing, growth reduction and perturbations in developmental parameters. The contamination of plants by shoot coating appeared to be less than through soil. Moreover, the increase of the degree of pollution induced more marked effects on plants, likely because of the physical effects of fuel. However, bioaccumulation of PAHs in shoot tissues was also found to be significant, even at very low levels of contamination, and highly related to the conditions of exposure to oil. The strong relationships between the PAH contents of Salicornia plants and growth reduction suggest a chemical toxicity of fuel oil, compounds like PAHs being known to inhibit physiological processes in plants. (author)

  4. The dark side of the salad: Salmonella typhimurium overcomes the innate immune response of Arabidopsis thaliana and shows an endopathogenic lifestyle.

    Directory of Open Access Journals (Sweden)

    Adam Schikora

    Full Text Available Salmonella enterica serovar typhimurium contaminated vegetables and fruits are considerable sources of human infections. Bacteria present in raw plant-derived nutrients cause salmonellosis, the world wide most spread food poisoning. This facultative endopathogen enters and replicates in host cells and actively suppresses host immune responses. Although Salmonella survives on plants, the underlying bacterial infection mechanisms are only poorly understood. In this report we investigated the possibility to use Arabidopsis thaliana as a genetically tractable host system to study Salmonella-plant interactions. Using green fluorescent protein (GFP marked bacteria, we show here that Salmonella can infect various Arabidopsis tissues and proliferate in intracellular cellular compartments. Salmonella infection of Arabidopsis cells can occur via intact shoot or root tissues resulting in wilting, chlorosis and eventually death of the infected organs. Arabidopsis reacts to Salmonella by inducing the activation of mitogen-activated protein kinase (MAPK cascades and enhanced expression of pathogenesis related (PR genes. The induction of defense responses fails in plants that are compromised in ethylene or jasmonic acid signaling or in the MKK3-MPK6 MAPK pathway. These findings demonstrate that Arabidopsis represents a true host system for Salmonella, offering unique possibilities to study the interaction of this human pathogen with plants at the molecular level for developing novel drug targets and addressing current safety issues in human nutrition.

  5. Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae).

    Science.gov (United States)

    Kieling-Rubio, M A; Droste, A; Windisch, P G

    2012-11-01

    The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyer's solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L(-1) of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L(-1) of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L(-1) of Ni, when compared with the treatment without this metal. At 4.8 mg L(-1), leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species. PMID:23295508

  6. Boechera species exhibit species-specific responses to combined heat and high light stress.

    Science.gov (United States)

    Gallas, Genna; Waters, Elizabeth R

    2015-01-01

    As sessile organisms, plants must be able to complete their life cycle in place and therefore tolerance to abiotic stress has had a major role in shaping biogeographical patterns. However, much of what we know about plant tolerance to abiotic stresses is based on studies of just a few plant species, most notably the model species Arabidopsis thaliana. In this study we examine natural variation in the stress responses of five diverse Boechera (Brassicaceae) species. Boechera plants were exposed to basal and acquired combined heat and high light stress. Plant response to these stresses was evaluated based on chlorophyll fluorescence measurements, induction of leaf chlorosis, and gene expression. Many of the Boechera species were more tolerant to heat and high light stress than A. thaliana. Gene expression data indicates that two important marker genes for stress responses: APX2 (Ascorbate peroxidase 2) and HsfA2 (Heat shock transcription factor A2) have distinct species-specific expression patterns. The findings of species-specific responses and tolerance to stress indicate that stress pathways are evolutionarily labile even among closely related species.

  7. Studies on antioxidative enzymes induced by cadmium in pea plants (Pisum sativum).

    Science.gov (United States)

    Pandey, Nalini; Singh, Gaurav Kumar

    2012-03-01

    Pea plants (Pisum sativum cv. Swati) exposed to different concentration of cadmium (50,100, 200 microM Cd) under controlled glass house conditions were quantified for different physiological parameters and antioxidative enzymes. In pea plants, Cd produced a significant inhibition of growth and induced chlorosis, marginal yellowing and necrosis in young leaves, the effect being most pronounced at 200 microM Cd supply. An alteration in the activated oxygen metabolism of pea plants were also detected as evidenced by an increase in concentration of H2O2 and TBARS along with decrease in the chlorophyll and carotenoid concentration in leaves. Cadmium toxicity induced an increase in non-protein thiol, ascorbate, proline and cysteine concentration. A significant increment in the activity of SOD, APX and GR, and a decrease in CAT was observed as a result of Cd treatment. The enhanced activity of SOD and inhibition of CAT and POD produces a high build up of H2O2 which appears to be the main cause of oxidative stress due to Cd toxicity in pea plants.

  8. Cytotoxicity, Genotoxicity, and Phytotoxicity of Tannery Effluent Discharged into Palar River Basin, Tamil Nadu, India

    Science.gov (United States)

    Roy, Suki; Nagarchi, Lubbnaz; Das, Ishita; Mangalam Achuthananthan, Jayasri; Krishnamurthy, Suthindhiran

    2015-01-01

    Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE) on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%). TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations. PMID:26839546

  9. ORGANOGÊNESE INDIRETA A PARTIR DE EXPLANTES FOLIARES E MULTIPLICAÇÃO IN VITRO DE BROTAÇÕES DE Eucalyptus benthamii X Eucalyptus dunnii

    Directory of Open Access Journals (Sweden)

    Yohana de Oliveira-Cauduro

    2014-01-01

    Full Text Available The aims of this research were to evaluate different culture media for indirect organogenesis and shoot multiplication of Eucalyptus benthamii x Eucalyptus dunnii . For organogenesis, leaf explants were used to test the following treatments: two culture media (MS N/2 and JADS supplemented with 0.1 μM 1-naphthaleneacetic acid (NAA and thidiazuron (TDZ (0.1 or 0.5 μ M, with or without PVP- 40 (250 mg L -1 . The percentage of oxidized explants, callus forming explants, explants with anthocyanin,buds, shoots and the shoot number per explant were evaluated. In the multiplication experiment, isolated shoots were cultivated in MS, JADS and WPM media, all supplemented with 1.11 μ M BAP. Four subcultures were carried out every 28 days. In every subculture the explant oxidation, partial or total leaf chlorosis, fresh mass and mean number of shoot per explant were evaluated. The MS N/2 medium supplemented with 0.1 μM NAA and 0.5 μM TDZ promoted the highest rate of organogenesis (8.3% and the culture media MS supplemented with 1.11 μ M BAP the multiplication rate was higher than in the other media, in the first and the second subcultures (9.28 and 9.24, respectively, without differences between the three media in the following subcultures.

  10. Cytotoxicity, Genotoxicity, and Phytotoxicity of Tannery Effluent Discharged into Palar River Basin, Tamil Nadu, India.

    Science.gov (United States)

    Roy, Suki; Nagarchi, Lubbnaz; Das, Ishita; Mangalam Achuthananthan, Jayasri; Krishnamurthy, Suthindhiran

    2015-01-01

    Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE) on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%). TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations. PMID:26839546

  11. GROWTH RESPONSE OF THE DUCKWEED LEMNA MINOR TO HEAVY METAL POLLUTION

    Directory of Open Access Journals (Sweden)

    N. Khellaf ، M. Zerdaoui

    2009-07-01

    Full Text Available To assess the tolerance and effect of heavy metals pollution on the duckweed Lemna minor, the aquatic plants were exposed to different concentrations of copper (Cu, nickel (Ni, cadmium (Cd and zinc (Zn in a quarter Coïc and Lessaint solution at pH = 6.1 (± 0.1 and under a daily regime of 16 h light (101 μmol/m2.s1. Copper at 0.2 mg/L and nickel at 0.5 mg/L promoted the growth of Lemna fronds. At higher concentrations, Cu and Ni inhibited the growth of duckweed; the EC50 (concentration causing 50% inhibition were 0.47 mg/L for Cu and 1.29 mg/L for Ni. Cadmium and zinc decreased by 50% the growth of fronds when the medium contained respectively 0.64 and 5.64 mg/L (EC50. Duckweed tolerated Cu, Ni, Cd and Zn at concentrations of 0.4, 3.0, 0.4 and 15.0 mg/L respectively without showing any visible signs of toxicity (chlorosis, frond disconnection and necrosis. On the basis of visible symptoms and the EC50 values, the toxicity of the metals on Lemna. minor was in decreasing order of damage: Cu > Cd > Ni > Zn. It was concluded that the duckweed Lemna. minor is very sensitive to copper and cadmium pollution.

  12. Homeotic-like modification of stamens to petals is associated with aberrant mitochondrial gene expression in cytoplasmic male sterile Ogura Brassica juncea

    Indian Academy of Sciences (India)

    Gargi Meur; K. Gaikwad; S. R. Bhat; S. Prakash; P. B. Kirti

    2006-08-01

    We have previously reported correction of severe leaf chlorosis in the cytoplasmic male sterile Ogura (also called Ogu) Brassica juncea line carrying Ogura cytoplasm by plastid substitution via protoplast fusion. Two cybrids obtained from the fusion experiment, Og1 and Og2, were green and carried the plastid genome of B. juncea cv. RLM198. While Og1 displayed normal flower morphology comparable to that of its euplasmic B. juncea counterpart except for sterile anthers, Og2 retained homeotic-like floral modification of stamens to petal-like structures and several other floral deformities observed in the chlorotic (Ogu) B. juncea cv. RLM198 (or OgRLM). With respect to the mitochondrial genome, Og1 showed 81% genetic similarity to the fertile cultivar RLM while Og2 showed 93% similarity to OgRLM. In spite of recombination and rearrangements in the mitochondrial genomes in the cybrids, expression patterns of 10 out of 11 mitochondrial genes were similar in all the three CMS lines; the only exception was atp6, whose expression was altered. While Og1 showed normal atp6 transcript similar to that in RLM, in Og2 and OgRLM weak expression of a longer transcript was detected. These results suggest that the homeotic-like changes in floral patterning leading to petaloid stamens in Og2 and OgRLM may be associated with aberrant mitochondrial gene expression.

  13. The physiological mechanisms underlying the ability of Cistus monspeliensis L. from São Domingos mine to withstand high Zn concentrations in soils.

    Science.gov (United States)

    Arenas-Lago, Daniel; Carvalho, Luísa C; Santos, Erika S; Abreu, M Manuela

    2016-07-01

    Cistus monspeliensis L. is a species that grows spontaneously in contaminated mining areas from the Iberian Pyrite Belt. This species can have high concentrations of Zn in the shoots without visible signs of phytotoxicity. In order to understand the physiological mechanisms underlying this tolerance, C. monspeliensis was grown at several concentrations of Zn(2+) (0, 500, 1000, 1500, 2000µM) and the effects of this metal on plant development and on the defence mechanisms against oxidative stress were evaluated. Independently of the treatment, Zn was mainly retained in the roots. The plants with the highest concentrations of Zn showed toxicity symptoms such as chlorosis, low leaf size and decrease in biomass production. At 2000µM of Zn, the dry biomass of the shoots decreased significantly. High concentrations of Zn in shoots did not induce deficiencies of other nutrients, except Cu. Plants with high concentrations of Zn had low amounts of chlorophyll, anthocyanins and glutathione and high contents of H2O2. The highest concentrations of Zn in shoots of C. monspeliensis triggered defence mechanisms against oxidative stress, namely by triggering antioxidative enzyme activity and by direct reactive oxygen species (ROS) scavenging through carotenoids, that are unaffected by stress due to stabilisation by ascorbic acid. PMID:27054705

  14. AtSWEET4, a hexose facilitator, mediates sugar transport to axial sinks and affects plant development.

    Science.gov (United States)

    Liu, Xiaozhu; Zhang, Yan; Yang, Chao; Tian, Zhihong; Li, Jianxiong

    2016-04-22

    Plants transport photoassimilates from source organs to sink tissues through the phloem translocation pathway. In the transport phloem, sugars that escape from the sieve tubes are released into the apoplasmic space between the sieve element/companion cell complex (SE/CC) and phloem parenchyma cells (PPCs) during the process of long-distance transport. The competition for sugar acquisition between SE/CC and adjoining PPCs is mediated by plasma membrane translocators. YFP-tagged AtSWEET4 protein is localized in the plasma membrane, and PromoterAtSWEET4-GUS analysis showed that AtSWEET4 is expressed in the stele of roots and veins of leaves and flowers. Overexpression of AtSWEET4 in Arabidopsis increases plant size and accumulates more glucose and fructose. By contrast, knock-down of AtSWEET4 by RNA-interference leads to small plant size, reduction in glucose and fructose contents, chlorosis in the leaf vein network, and reduction in chlorophyll content in leaves. Yeast assays demonstrated that AtSWEET4 is able to complement both fructose and glucose transport deficiency. Transgenic plants of AtSWEET4 overexpression exhibit higher freezing tolerance and support more growth of bacterium Pseudomonas syringae pv. phaseolicola NPS3121. We conclude that AtSWEET4 plays an important role in mediating sugar transport in axial tissues during plant growth and development.

  15. Elimination of browning exudate and in vitro development of shoots in Pistacia vera L. cv. mateur and Pistacia atlantica Desf. Culture

    Directory of Open Access Journals (Sweden)

    M. I. Trujillo

    2014-02-01

    Full Text Available We report diminution and/or elimination of browning exudate followed by in vitro establishment of in Pistacia vera cv. mateur and Pistacia atlantica explants. Soaking P. vera cv. mateur explants prior to culture in L-cysteine HCl for 15 min (100 µM inhibits blackening of the modified Murashige and Skoog medium - MS + 400 mg/l NH4NO3 - and of the explants; while shoot formation was increased. The browning in P. vera cv. mateur and P. atlantica explants dissolved when modified MS and Quoirin and Lepoivre - QL.4 - media were supplemented with activated charcoal (from 1 to 3 g l-1 and with 4 and 8 days of darkness. These treatments were enough to eliminate browning from the explants and to improve the shoots elongation, but symptoms of chlorosis were detected. On the other hand, AgNO3 (from 15 to 40 µ1V1 showed a very strong antibrowning effect on the medium and explants of P. atlantica. Thus shoot organogenesis was best achieved and the developing sturdy shoots had large and green leaves.

  16. Cytotoxicity, Genotoxicity, and Phytotoxicity of Tannery Effluent Discharged into Palar River Basin, Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    Suki Roy

    2015-01-01

    Full Text Available Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%. TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations.

  17. Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

    Energy Technology Data Exchange (ETDEWEB)

    Xiaodong Huang; Dixon, D.G.; Greenberg, B.M. (Univ., of Waterloo, Ontario (Canada). Dept. of Biology)

    1993-06-01

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive [pi]-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions and potentially by photomodification of the chemicals to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, the authors investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activated the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid, and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated.

  18. Investigations into the organism level effects of the copper-induced oxidative stress response of Lemna gibba

    Energy Technology Data Exchange (ETDEWEB)

    Wall, V.D.; Klaine, S.J. [Clemson Univ., Pendleton, SC (United States)

    1995-12-31

    The use of biochemical endpoints to indicate exposure to environmental toxicants is becoming an accepted technique to determine chemical bio-availability. However, these biochemical endpoints, or biomarkers, have not fulfilled their potential as indicators of sublethal stress when used in this capacity. Difficulties associated with using biochemical endpoints to assess stress arise in differentiating an ``abnormal`` stress response from a physiologically acceptable one and identifying sublethal stress in a biologically and ecologically significant manner. This research examines organism level effects of the copper-induced oxidative-stress response in Lemna gibba. The growth of Lemna gibba was significantly inhibited by aqueous copper concentrations greater than 0.05 ppm during a 10 day exposure. Although effects were dose dependent, the results indicated a conspicuous decrease in growth rates and increase in malformation and chlorosis at 0.5 ppm copper and higher. There were significantly elevated levels of lipid peroxidation products (expressed as thiobarbituric acid reactive species (TBARS)) at 0.1 ppm copper and higher. A decrease in growth rates without an increase in TBARS suggested a diversion of energy towards defensive mechanisms, primarily, superoxide dismutase, peroxidase, catalase and glutathione. These parameters were investigated and analyzed with respect to the organism-level effects (growth rates) of Lemna gibba. The utility and relevance of these sub-cellular parameters as indicators of chemical induced stress at the organism level will be discussed.

  19. Phytoassessment of acid mine drainage: Lemna gibba bioassay and diatom community structure.

    Science.gov (United States)

    Gerhardt, A; de Bisthoven, L Janssens; Guhr, K; Soares, A M V M; Pereira, M J

    2008-01-01

    An integrated multilevel phytoassessment of an acid mine drainage (AMD, pH range 3.3-6.8) in southern Portugal was performed. A 7-day phytotoxicity bioassay with the duckweed Lemna gibba (chlorosis, necrosis, growth) was carried out, both in the laboratory and in situ, combined with an analysis of the resident epilithic diatom community. The toxicity test was performed with water from the AMD gradient, an unpolluted river control and acidified control water, in order to discriminate potential pH-effects from combined pH- and metal-effects. Diatom communities discriminated well among the sites (alkalophilic species versus halobiontic, acidobiontic and acidophilic species), showing inter-site differences to be larger than intra-site seasonal variations. In L. gibba exposed to AMD, necrosis and growth inhibition were higher in situ compared to the laboratory experiments. L. gibba was more sensitive to AMD than to acidified water. Already after 4 days, growth rate inhibition in L. gibba proved to be a reliable indicator of AMD-stress. Ecotoxicological thresholds obtained with L. gibba corresponded with those obtained previously with animals of intermediate tolerance to AMD. The results were summarised in a multimetric index. PMID:17952593

  20. Photoinduced toxicity of sediment-bound polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, B.M.; Duxbury, C.L.; Marwood, C.A.; Huang, X.D.; Dixon, D.G. [Univ. of Waterloo, Ontario (Canada)

    1994-12-31

    Polycyclic aromatic hydrocarbons (PAHs) are known to be both mutagenic and toxic. Light, in particular UV irradiation, increases their toxicity. Since aquatic plants cannot avoid PAHs or light, they are at risk. However, the major loadings of PAHs are in sediment. In this study the authors examined the assimilation of both intact and photomodified labelled PAHs bound to a surrogate, sediment (sand) by the higher aquatic plant Lemna gibba L. G-3. They found that simulated solar radiation significantly promoted the release of PAHs from sand and their assimilation by Lemna, although assimilation from the solid phase was slower than for chemicals placed directly into the aqueous medium. Toxicity of PAHs bound to sand was then measured by exposing plants to the sand-chemical composite for 8 d. Plants were exposed to both visible and SSR light conditions during this period, and toxicity was measured as inhibition of growth, inhibition of photosynthesis (chlorophyll fluorescence induction) and chlorosis. All three endpoints indicated that PAHs bound to a sediment phase can express phototoxicity and that the effects are most strongly promoted by the UV region of the solar spectrum. The authors have now extended this work to probe the effects of UV-B and PAHs on chloroplast development, with the finding that both stresses inhibit development of the photosynthetic apparatus.

  1. Toxicity of 14 photooxidized anthracene derivatives to Lemna gibba L.G-3

    Energy Technology Data Exchange (ETDEWEB)

    Mallakin, A.; MacConkey, B.J.; McKibbenyen, B.; Sniekusyen, V.; Dixon, D.G.; Greenberg, B.M. [Univ. of Waterloo, Ontario (Canada)

    1995-12-31

    Phototoxicity of PAHs is known to occur via photosensitization reactions and potentially by photomodification of chemicals to more toxic species. The hazards enhancement of polycyclic aromatic hydrocarbon (PAHs) toxicity to plants by artificial light source and natural solar radiation has been recently demonstrated. Growth and chlorosis were used as end points to assess the photoinduced toxicity to 14 oxygenated anthracene derivatives to Lemna gibba. Reversed-phase liquid chromatography (HPLC) equipped with diode array detector was used as analytical technique for measurement of polycyclic aromatic hydrocarbons photomodification products and to study the modification kinetics. The toxicity bioassays were performed both under visible light and simulated solar radiation (SSR), which mimicked the relative load of UV + visible light in solar radiation. Comparative studies with visible and SSR showed that the phototoxicity of these chemicals was activated, with UV radiation being the most influenced spectral region in enhancing the harmful effects of the chemicals. Photomodified PAHs exhibited toxicity in visible light and increased toxicity in simulate solar radiation. The rates of photomodification of chemicals were quite different but rapid enough to contribute to toxicity. There was increase in inhibition of growth of plants, relative to control, with increasing in rate of photomodification of the oxygenated PAHs.

  2. Calcium Mitigates Arsenic Toxicity in Rice Seedlings by Reducing Arsenic Uptake and Modulating the Antioxidant Defense and Glyoxalase Systems and Stress Markers.

    Science.gov (United States)

    Rahman, Anisur; Mostofa, Mohammad Golam; Alam, Md Mahabub; Nahar, Kamrun; Hasanuzzaman, Mirza; Fujita, Masayuki

    2015-01-01

    The effect of exogenous calcium (Ca) on hydroponically grown rice seedlings was studied under arsenic (As) stress by investigating the antioxidant and glyoxalase systems. Fourteen-day-old rice (Oryza sativa L. cv. BRRI dhan29) seedlings were exposed to 0.5 and 1 mM Na2HAsO4 alone and in combination with 10 mM CaCl2 (Ca) for 5 days. Both levels of As caused growth inhibition, chlorosis, reduced leaf RWC, and increased As accumulation in the rice seedlings. Both doses of As in growth medium induced oxidative stress through overproduction of reactive oxygen species (ROS) by disrupting the antioxidant defense and glyoxalase systems. Exogenous application of Ca along with both levels of As significantly decreased As accumulation and restored plant growth and water loss. Calcium supplementation in the As-exposed rice seedlings reduced ROS production, increased ascorbate (AsA) content, and increased the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glutathione peroxidase (GPX), superoxide dismutase (SOD), and the glyoxalase I (Gly I) and glyoxalase II (Gly II) enzymes compared with seedlings exposed to As only. These results suggest that Ca supplementation improves rice seedlings tolerance to As-induced oxidative stress by reducing As uptake, enhancing their antioxidant defense and glyoxalase systems, and also improving growth and physiological condition.

  3. Yield comparisons and unique characteristics of the dwarf wheat cultivar `USU-Apogee'

    Science.gov (United States)

    Bugbee, B.; Koerner, G.

    1997-01-01

    Extremely short, high yielding cultivars of all crop plants are needed to optimize the food production of bioregenerative life support systems in space. In the early 1980's, we examined over a thousand wheat genotypes from the world germplasm collection in search of genotypes with appropriate characteristics for food production in space. Here we report the results of 12 years of hybridization and selection for the perfect wheat cultivar. `USU-Apogee' is a full-dwarf hard red spring wheat (Triticum aestivum L.) cultivar developed for high yields in controlled environments. USU-Apogee was developed by the Utah Agricultural Experiment Station in cooperation with the National Aeronautics and Space Administration and released in April 1996. USU-Apogee is a shorter, higher yielding alternative to `Yecora Rojo' and `Veery-10', the short field genotypes previously selected for use in controlled environments. The yield advantage of USU-Apogee is 10 to 30% over these other cultivars, depending on environmental conditions. USU-Apogee (45-50 cm tall, depending on temperature) is 10 to 15 cm shorter than Yecora Rojo and 1 to 4 cm shorter than Veery-10. USU-Apogee was also selected for resistance to the calcium-induced leaf tip chlorosis that occurs in controlled-environments. Breeder seed of USU-Apogee will be maintained by the Crop Physiology Laboratory and seed is available for testing on request.

  4. Heavy Metal Stress and Some Mechanisms of Plant Defense Response

    Directory of Open Access Journals (Sweden)

    Abolghassem Emamverdian

    2015-01-01

    Full Text Available Unprecedented bioaccumulation and biomagnification of heavy metals (HMs in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS. This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs or metallothioneins (MTs metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants.

  5. Monitoring the sensitivity of selected crops to lead, cadmium and arsenic

    Directory of Open Access Journals (Sweden)

    Piršelová B.

    2011-12-01

    Full Text Available Heavy metals are highly toxic environmental pollutants. In plants, these compounds cause numerous slighter or stronger toxic effects. They inhibit root and shoot growth and yield production, affect nutrient uptake and homeostasis, and are frequently accumulated by agriculturally important crops. Effects of heavy metals on five selected species of agricultural crops were monitored. We focused our attention to general and commonly used stress indicators such as seed germination, weight and length of roots and shoots. Each of these characteristics was dependent on the tested plant species and tested heavy metals. Dosage of lead (500 mg/l had little effect on seed germination, cadmium (300 mg/l significantly affected seed germination of pea and barley, arsenic (100 mg/l caused total inhibition of seed germination in all tested plant species. Plants grow in soil contaminated with heavy metals showed several symptoms of metal toxicity (chlorosis, necrosis of leaf tips, blackening of roots. In general, the highest tolerance to tested metal ions was observed in both varieties of bean, and the lowest sensitivity was observed in soybean plants. The highest degree of toxicity was shown to have tested doses of cadmium and arsenic, the lowest the doses of lead. In general, the lowest tolerance indexes were determined based on the decrease in fresh weight of roots.

  6. Genetic interactions reveal that specific defects of chloroplast translation are associated with the suppression of var2-mediated leaf variegation.

    Science.gov (United States)

    Liu, Xiayan; Zheng, Mengdi; Wang, Rui; Wang, Ruijuan; An, Lijun; Rodermel, Steve R; Yu, Fei

    2013-10-01

    Arabidopsis thaliana L. yellow variegated (var2) mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGATION8 (SVR8), which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr8 23S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, S21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2 variegation and the existence of complex genetic interactions in chloroplast development. PMID:23721655

  7. The memory of iron stress in strawberry plants.

    Science.gov (United States)

    Gama, Florinda; Saavedra, Teresa; da Silva, José Paulo; Miguel, Maria Graça; de Varennes, Amarilis; Correia, Pedro José; Pestana, Maribela

    2016-07-01

    To provide information towards optimization of strategies to treat Fe deficiency, experiments were conducted to study the responses of Fe-deficient plants to the resupply of Fe. Strawberry (Fragaria × ananassa Duch.) was used as model plant. Bare-root transplants of strawberry (cv. 'Diamante') were grown for 42 days in Hoagland's nutrient solutions without Fe (Fe0) and containing 10 μM of Fe as Fe-EDDHA (control, Fe10). For plants under Fe0 the total chlorophyll concentration of young leaves decreased progressively on time, showing the typical symptoms of iron chlorosis. After 35 days the Fe concentration was 6% of that observed for plants growing under Fe10. Half of plants growing under Fe0 were then Fe-resupplied by adding 10 μM of Fe to the Fe0 nutrient solution (FeR). Full Chlorophyll recovery of young leaves took place within 12 days. Root ferric chelate-reductase activity (FCR) and succinic and citric acid concentrations increased in FeR plants. Fe partition revealed that FeR plants expressively accumulated this nutrient in the crown and flowers. This observation can be due to a passive deactivation mechanism of the FCR activity, associated with continuous synthesis of succinic and citric acids at root level, and consequent greater uptake of Fe. PMID:27010743

  8. Impacts of the Deepwater Horizon oil spill on the salt marsh vegetation of Louisiana.

    Science.gov (United States)

    Hester, Mark W; Willis, Jonathan M; Rouhani, Shahrokh; Steinhoff, Marla A; Baker, Mary C

    2016-09-01

    The coastal wetland vegetation component of the Deepwater Horizon oil spill Natural Resource Damage Assessment documented significant injury to the plant production and health of Louisiana salt marshes exposed to oiling. Specifically, marsh sites experiencing trace or greater vertical oiling of plant tissues displayed reductions in cover and peak standing crop relative to reference (no oiling), particularly in the marsh edge zone, for the majority of this four year study. Similarly, elevated chlorosis of plant tissue, as estimated by a vegetation health index, was detected for marsh sites with trace or greater vertical oiling in the first two years of the study. Key environmental factors, such as hydrologic regime, elevation, and soil characteristics, were generally similar across plant oiling classes (including reference), indicating that the observed injury to plant production and health was the result of plant oiling and not potential differences in environmental setting. Although fewer significant impacts to plant production and health were detected in the latter years of the study, this is due in part to decreased sample size occurring as a result of erosion (shoreline retreat) and resultant loss of plots, and should not be misconstrued as indicating full recovery of the ecosystem. PMID:27299994

  9. Comparative chemical screening and genetic analysis reveal tentoxin as a new virulence factor in Cochliobolus miyabeanus, the causal agent of brown spot disease on rice.

    Science.gov (United States)

    De Bruyne, Lieselotte; Van Poucke, Christof; Di Mavungu, Diana Jose; Zainudin, Nur Ain Izzati Mohd; Vanhaecke, Lynn; De Vleesschauwer, David; Turgeon, B Gillian; De Saeger, Sarah; Höfte, Monica

    2016-08-01

    Brown spot disease, caused by Cochliobolus miyabeanus, is currently considered to be one of the most important yield reducers of rice (Oryza sativa L.). Despite its agricultural importance, little is known about the virulence mechanisms deployed by the fungus. Therefore, we set out to identify novel virulence factors with a role in disease development. This article reports, for the first time, the production of tentoxin by C. miyabeanus as a virulence factor during brown spot disease and the identification of the non-ribosomal protein synthetase (NRPS) CmNps3, responsible for tentoxin biosynthesis. We compared the chemical compounds produced by C. miyabeanus strains differing in virulence ability using ultra-high-performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry (HRMS). The production of tentoxin by a highly virulent strain was revealed by principal component analysis of the detected ions and confirmed by UHPLC coupled to tandem-quadrupole mass spectrometry (MS/MS). The corresponding NRPS was identified by in silico genome analysis and confirmed by gene deletion. Infection tests with wild-type and Cmnps3 mutants showed that tentoxin acts as a virulence factor and is correlated with chlorosis development during the second phase of infection. Although rice has previously been classified as a tentoxin-insensitive plant species, our data demonstrate that tentoxin production by C. miyabeanus affects symptom development. PMID:26456797

  10. Maize ZmFDR3 localized in chloroplasts is involved in iron transport

    Institute of Scientific and Technical Information of China (English)

    HAN JianHui; SONG XiuFang; LI Peng; YANG HuiJun; YIN LiPing

    2009-01-01

    Iron is an essential nutrient for plant metabolism such that Fe-limited plants display chlorosis and suffer from reduced photosynthetic efficiency. Differential display previously identified genes whose expression was elevated in Fe-deficient maize roots. Here, we describe the functional characterization of one of the genes identified in the screen, ZmFDR3 (Zea maize Fe-deficiency-related). Heterologous functional complementation assays using a yeast iron uptake mutant showed that ZmFDR3 functions in iron transport. ZmFDR3 contains a domain found in FliN-proteins of the type Ⅲ secretion system and is predicted to localize to the thylakoid of plastids. Fluorescence immunocytochemistry showed that ZmFDR3 is localized in the plastids of roots, stems and leaves, with high expression found in guard cell chloroplasts. Transgenic tobacco expressing a 355-ZmFDR3 construct contains elevated iron content, displays well arranged thylakoid membranes and has photosynthetic indices that are higher than those of the wild type. Together, these results suggest that ZmFDR3 functions in chloroplast iron transport.

  11. The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis.

    Science.gov (United States)

    Krüßel, Lena; Junemann, Johannes; Wirtz, Markus; Birke, Hannah; Thornton, Jeremy D; Browning, Luke W; Poschet, Gernot; Hell, Rüdiger; Balk, Janneke; Braun, Hans-Peter; Hildebrandt, Tatjana M

    2014-05-01

    The sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) catalyzes the oxidation of persulfides in the mitochondrial matrix and is essential for early embryo development in Arabidopsis (Arabidopsis thaliana). We investigated the biochemical and physiological functions of ETHE1 in plant metabolism using recombinant Arabidopsis ETHE1 and three transfer DNA insertion lines with 50% to 99% decreased sulfur dioxygenase activity. Our results identified a new mitochondrial pathway catalyzing the detoxification of reduced sulfur species derived from cysteine catabolism by oxidation to thiosulfate. Knockdown of the sulfur dioxygenase impaired embryo development and produced phenotypes of starvation-induced chlorosis during short-day growth conditions and extended darkness, indicating that ETHE1 has a key function in situations of high protein turnover, such as seed production and the use of amino acids as alternative respiratory substrates during carbohydrate starvation. The amino acid profile of mutant plants was similar to that caused by defects in the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex and associated dehydrogenases. Thus, in addition to sulfur amino acid catabolism, ETHE1 also affects the oxidation of branched-chain amino acids and lysine.

  12. Genomics and X-ray microanalysis indicate that Ca2+ and thiols mediate the aggregation and adhesion of Xylella fastidiosa

    Directory of Open Access Journals (Sweden)

    B. Leite

    2002-06-01

    Full Text Available The availability of the genome sequence of the bacterial plant pathogen Xylella fastidiosa, the causal agent of citrus variegated chlorosis, is accelerating important investigations concerning its pathogenicity. Plant vessel occlusion is critical for symptom development. The objective of the present study was to search for information that would help to explain the adhesion of X. fastidiosa cells to the xylem. Scanning electron microscopy revealed that adhesion may occur without the fastidium gum, an exopolysaccharide produced by X. fastidiosa, and X-ray microanalysis demonstrated the presence of elemental sulfur both in cells grown in vitro and in cells found inside plant vessels, indicating that the sulfur signal is generated by the pathogen surface. Calcium and magnesium peaks were detected in association with sulfur in occluded vessels. We propose an explanation for the adhesion and aggregation process. Thiol groups, maintained by the enzyme peptide methionine sulfoxide reductase, could be active on the surface of the bacteria and appear to promote cell-cell aggregation by forming disulfide bonds with thiol groups on the surface of adjacent cells. The enzyme methionine sulfoxide reductase has been shown to be an auxiliary component in the adhesiveness of some human pathogens. The negative charge conferred by the ionized thiol group could of itself constitute a mechanism of adhesion by allowing the formation of divalent cation bridges between the negatively charged bacteria and predominantly negatively charged xylem walls.

  13. Specific amplification of iron receptor genes in Xylella fastidiosa strains from different hosts

    Directory of Open Access Journals (Sweden)

    Flávia Teresa Hansen Pacheco

    2006-01-01

    Full Text Available Bacterial production of siderophores may involve specific genes related to nonribosomal peptide and polyketide biosynthesis, which have not been fully identified in the genome of Xylella fastidiosa strain 9a5c. However, a search for siderophore-related genes in strain 9a5c indicated five membrane receptors, including siderophore, ferrichrome-iron and hemin receptors. All these biomolecules are thought to be associated with iron transport and utilization. Eighty isolates obtained from citrus orchards containing trees that developed citrus variegated chlorosis (CVC were screened for siderophore production. The results demonstrated that only 10 of the isolates did not produce siderophores. Additional strains obtained from coffee, almond, mulberry, elm, ragweed, periwinkle and grape also infected by X. fastidiosa were also shown by the chromeazurol bioassay to produce siderophores. In order to correlate siderophore production with the presence of siderophore-related genes, a polymerase chain reaction (PCR was developed using specific primers for the catechol-type ferric enterobactin receptor (pfeA and the hydroxamate-type ferrisiderophore receptor (fiuA genes of strain 9a5c. The PCR results confirmed our hypothesis by demonstrating that amplification products were detected in all strains except for those isolates that did not produce siderophores.

  14. Genome wide association mapping for the tolerance to the polyamine oxidase inhibitor guazatine in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Kostadin Evgeniev eAtanasov

    2016-04-01

    Full Text Available Guazatine is a potent inhibitor of polyamine oxidase (PAO activity. In agriculture, guazatine is used as non-systemic contact fungicide efficient in the protection of cereals and citrus fruits against disease. The composition of guazatine is complex, mainly constituted by a mixture of synthetic guanidated polyamines (polyaminoguanidines. Here we have studied the effects from exposure to guazatine in the weed Arabidopsis thaliana. We report that micromolar concentrations of guazatine are sufficient to inhibit growth of Arabidopsis seedlings and induce chlorosis, whereas germination is barely affected. We observed the occurrence of quantitative variation in the response to guazatine between 107 randomly chosen Arabidopsis accessions. This enabled us to undertake genome-wide association (GWA mapping that identified a locus on chromosome one associated with guazatine tolerance. CHLOROPHYLLASE 1 (CLH1 within this locus was studied as candidate gene, together with its paralog (CLH2. The analysis of independent clh1-2, clh1-3, clh2-3, clh2-2 and double clh1-2 clh2-3 mutant alleles indicated that CLH1 and/or CLH2 loss-of-function or expression down-regulation promote guazatine tolerance in Arabidopsis. We report a natural mechanism by which Arabidopsis populations can overcome toxicity by the fungicide guazatine.

  15. The effect of rootstocks on the growth and yielding of sour cherry cv. 'Łutówka'

    Directory of Open Access Journals (Sweden)

    Stanisław Wociór

    2012-12-01

    Full Text Available The strength of growth of 'Łutówka' trees was related to the soil quality and the rootstock. Measurements of the tree trunks and the crown size showed that on fertile soil the trees grafted on Mahaleb cherry grew worse, forming by 12% thinner trunks and by over 20% (significantly smaller crowns as compared to Mazzard cherry trees. On poor sandy-loamy soil the crowns of trees grafted on Mahaleb were significantly, more than 40% bigger than those on Mazzard cherry. No significant differences in the yielding and productivity of trees grafted on Mahaleb and Mazzard cherry trees were found on grey brown podzolic soil. The experiment conducted on sandy-loamy soil pointed to significant differences in the yielding and productivity between 'Łutówka' trees grafted on the studied rootstocks. The trees grafted on Mahaleb cherry in both studied years were characterized by significantly greater productivity than on the other rootstocks. Significantly higher yields were gathered from the trees on Mahaleb cherry than on vegetative rootstocks, and by 70% higher than on Mazzard cherry. P-HL A rootstock is of little use in the planting of 'Łutówka', which grown poorly on light soils. Besides poor growth and yielding, in longer dry periods the studies found the appearance of chlorosis of magnesium on older leaves, and even wilting of the leaves.

  16. Serological and molecular detection of Prune dwarf virus infecting stone fruits of Charmahal-va-Bakhtiari province, a central region of Iran

    Directory of Open Access Journals (Sweden)

    Nourolah Soltani

    2013-09-01

    Full Text Available Prune dwarf virus (PDV is one of the major positive RNA viruses which cause economical damages in stone fruit trees. The symptoms of PDV vary between different stone fruits namely sour and sweet cherry, almond, peach, apricot and plum including leaf narrowing, leaf chlorosis, vein clearing, mosaic, leaf whitening, leathery leaf, bushy branches and stunt trees. During the years 2011 and 2012, 251 leaf samples were collected for detection of PDV in stone fruit orchards of Charmahal-va-Bakhtiari province. DAS-ELISA test proved PDV presence serologically. Then, total RNA were extracted and tested by two-step RT-PCR which replicated partial and full coat protein sequence of PDV. One hundred and eighty one out of total samples (251 samples showed PDV infection using serological and two-step RT-PCR assays, hence, incidence of PDV in Charmahal-va-Bakhtiari province was confirmed. This is the first report of PDV in stone fruit orchards of Charmahal-va-Bakhtiari province and in Iran.

  17. Ammonium improves iron nutrition by decreasing leaf apoplastic pH of sunflower plants (Helianthus annuus L. cv. Frankasol)

    Institute of Scientific and Technical Information of China (English)

    ZOU Chunqin; ZHANG Fusuo

    2003-01-01

    The effect of nitrogen form on pH and concentration of soluble iron (Fe) in leaf apoplast was investigated in hydrophonically grown sunflower plants (Helianthus annuus L. cv. Frankasol), and the mechanism underlying the improved Fe nutrition by ammonium (NH4) supply was also elucidated. Ammonium supply ameliorated Fe nutrition of plants grown without Fe through decreasing apoplastic pH and increasing soluble Fe concentration in apoplastic fluid of young leaves. The soluble Fe concentration in apoplastic fluid and cell sap of young leaves, and xylem exudates of NH4 fed-plants was higher than that of nitrate (NO3) fed-plants, and no typical Fe-deficiency chlorosis in young leaves was observed in NH4 fed plant without Fe supply. The apoplastic pH was 6.15 and 5.94 in young leaves of Fe-deficient plants fed respectively with NO3 and NH4, while in Fe-sufficient plants, the apoplastic pH was 6.43 with NO3, and 5.50 with NH4 supply. In primary leaves, the apoplastic pH was around 6.25 irrespective of nitrogen form and Fe supply. The pH of xylem exudate was 5.72 in Fe-deficient plants fed with NO3 and 5.49 with NH4. Iron nutrition increased the pH of xylem exudate by 0.27 and 0.16 unit under NO3 and NH4 supply respectively.

  18. Glucose alleviates cadmium toxicity by increasing cadmium fixation in root cell wall and sequestration into vacuole in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yuan-Zhi Shi; Xiao-Fang Zhu; Jiang-Xue Wan; Gui-Xin Li; Shao-Jian Zheng

    2015-01-01

    Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadmium (Cd) concentration, and rescued Cd-induced chlorosis in Arabidopsis thaliana (Columbia ecotype, Col-0) under Cd stressed conditions. Glucose increased Cd retained in the roots, thus reducing its translocation from root to shoot significantly. The most Cd retained in the roots was found in the hemicellulose 1. Glucose combined with Cd (Glu þ Cd) treatment did not affect the content of pectin and its binding capacity of Cd while it increased the content of hemicelluloses 1 and the amount of Cd retained in it significantly. Furthermore, Leadmium Green staining indicated that more Cd was compartmented into vacuoles in Glu þ Cd treatment compared with Cd treatment alone, which was in accordance with the significant upregulation of the expression of tonoplast-localized metal transporter genes, suggesting that com-partmentation of Cd into vacuoles also contributes to the Glu-alleviated Cd toxicity. Taken together, we demonstrated that Glu-alleviated Cd toxicity is mediated through increas-ing Cd fixation in the root cell wall and sequestration into the vacuoles.

  19. Effects of experimental acid precipitation and liming on vigor, species abundance, and mineral nutrition of ground vegetation in a Norway spruce stand

    Energy Technology Data Exchange (ETDEWEB)

    Rodenkirchen, H.

    1986-09-01

    The effects of simulated sulfuric acid rain and liming on ground vegetation of a 74-year-old Norway Spruce stand were analysed since summer of 1983. During the first two growing seasons no significant change in species composition had occurred on any plot. The frequently applied acid rain injured some constant moss species, this was reflected by chlorosis, necroses, and reduced average coverage or frequency. Damaged moss segments had decreased Ca-, Mg-, Mn-, Zn- and K-concentrations. Some secondary moss species, however were more tolerant to acid precipitation. Liming with dolomite at the beginning of the experiment improved the Ca- and Mg-nutrition of all investigated species (Thuidium tamariscinum, Oxalis acetosella, spruce seedlings), lowered the intensity of injury by acid rain with mosses, and reduced the Mn- (and Zn-)uptake of the vascular plant species. The combination of liming and irrigation with acid or 'normal' water strongly increased the abundance of the herb Oxalis acetosella. Without liming the same species responded to acid rain with lower Ca- (and Mg-)contents in leaves but no visible foliar damage occurred.

  20. Alteration of extracellular enzymes in pinto bean leaves upon exposure to air pollutants, ozone and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Peters, J.L.; Castillo, F.J.; Heath, R.L. (Univ. of California, Riverside (USA))

    1989-01-01

    Diamine oxidase and peroxidase, associated with the wall in pinto bean (Phaseolus vulgaris L. var Pinto) leaves, can be washed out by vacuum infiltration and assayed without grinding the leaf. The diamine oxidase activity is inhibited in vivo by exposure of the plants to ozone (dose of 0.6 microliters per liter {times} hour), whereas the peroxidase activity associated with the wall space is stimulated. This dose does not cause obvious necrosis or chlorosis of the leaf. These alterations are greater when the dose of ozone exposure is given as a triangular pulse (a slow rise to a peak of 0.24 microliters per liter followed by a slow fall) compared to that given as a constant square wave pulse of 0.15 microliters per liter for the same 4 hour period. Exposure of the plants to sulfur dioxide (at a concentration of 0.4 microliters per liter for 4 hours) does not result in any change in the diamine oxidase or peroxidase activities, yet the total sulfhydryl content of the leaf is increased, demonstrating the entry of sulfur dioxide. These two pollutants, with different chemical reactivities, affect the activities of the extracellular enzymes in different manners. In the case of ozone exposure, the inhibition of extracellular diamine oxidase could profoundly alter the movements of polyamines from cell to cell.

  1. Enhanced biosynthesis of quercetin occurs as A photoprotective measure in Lycopersicon esculentum mill. under Acute UV-B exposure

    Directory of Open Access Journals (Sweden)

    Abhilasha Shourie

    2014-06-01

    Full Text Available Lycopersicon esculentum respond to UV-B by enhanced synthesis of flavonoid quercetin, a strong antioxidant that helps the plants to well acclimatize to UV-B stress. Three weeks old plants of L. esculentum were subjected to acute UV-B irradiation for 20, 40 and 60 minutes daily until 28 days and analyzed for the morphological and biochemical changes. UV-B exposure for 40 and 60 minutes considerably affected the growth and biomass of L. esculentum. The leaves were deformed, developed chlorosis and abscised early as compared to the unexposed plants. Biomass declined by 35% and total chlorophyll decreased by 24.7% due to disintegration of chloroplasts. Enhancement was seen in the content of carotenoids, anthocyanins and total flavonoids by 15, 33.3 and 22.8%, respectively, which was attributed to the photoprotective role of these compounds as potential quenchers of excess excitation energy. Quercetin content decreased on UV-B exposure to 20 and 40 min, and thereafter increased significantly by 5.19% on 60 min of exposure. This pattern probably indicated that the over-expression of genes involved in its biosynthesis such as phenylalanine ammonia lyase (PAL, chalcone synthase (CHS, flavanone 3-hydroxylase (F3H and dihydroflavonol 4-reductase (DFR occurred only after certain threshold exposure (60 min, which could be the strategy for developing tolerance against UV-B stress in L. esculentum.

  2. Identification of Tomato Leaf Factors that Activate Toxin Gene Expression in Pseudomonas syringae pv. tomato DC3000.

    Science.gov (United States)

    Li, X Z; Starratt, A N; Cuppels, D A

    1998-10-01

    ABSTRACT Coronatine is a non-host-specific chlorosis-inducing phytotoxin produced by the tomato and crucifer pathogen Pseudomonas syringae pv. tomato DC3000. How the chromosomal gene cluster controlling toxin synthesis in this strain is regulated in planta is unknown. Ice nucleation-active cor:inaZ marker-exchange derivatives of strain DC3000 were used to determine coronatine gene expression in various host and nonhost plants and in a minimal medium supplemented with selected tomato plant constituents. Ice nucleation activity, which was first detected 4 h after inoculation, was highest in cabbage, tomato, and soybean and lowest in melon and cucumber. No correlation existed between bacterial population size and expression level on the various plants. Crude tomato leaf extract and intercellular fluid were strong inducers of toxin synthesis. Based on high-performance liquid chromatography analyses and bioassays, we concluded that the active components of both preparations were malic and citric acids, with minor contributions coming from shikimic and quinic acid. Although several compounds including glucose and inositol activated the toxin genes when tested at high concentrations (3 to 5 mM), shikimic and quinic acids were the only ones with activity at concentrations below 0.1 mM. Neither acid could be used as a sole carbon source by strain DC3000. The signal activity of shikimic acid was enhanced 10-fold by the addition of glucose. None of the plant phenolics that we screened affected coronatine gene expression. PMID:18944822

  3. Arabidopsis copper transport protein COPT2 participates in the cross talk between iron deficiency responses and low-phosphate signaling.

    Science.gov (United States)

    Perea-García, Ana; Garcia-Molina, Antoni; Andrés-Colás, Nuria; Vera-Sirera, Francisco; Pérez-Amador, Miguel A; Puig, Sergi; Peñarrubia, Lola

    2013-05-01

    Copper and iron are essential micronutrients for most living organisms because they participate as cofactors in biological processes, including respiration, photosynthesis, and oxidative stress protection. In many eukaryotic organisms, including yeast (Saccharomyces cerevisiae) and mammals, copper and iron homeostases are highly interconnected; yet, such interdependence is not well established in higher plants. Here, we propose that COPT2, a high-affinity copper transport protein, functions under copper and iron deficiencies in Arabidopsis (Arabidopsis thaliana). COPT2 is a plasma membrane protein that functions in copper acquisition and distribution. Characterization of the COPT2 expression pattern indicates a synergic response to copper and iron limitation in roots. We characterized a knockout of COPT2, copt2-1, that leads to increased resistance to simultaneous copper and iron deficiencies, measured as reduced leaf chlorosis and improved maintenance of the photosynthetic apparatus. We propose that COPT2 could play a dual role under iron deficiency. First, COPT2 participates in the attenuation of copper deficiency responses driven by iron limitation, possibly to minimize further iron consumption. Second, global expression analyses of copt2-1 versus wild-type Arabidopsis plants indicate that low-phosphate responses increase in the mutant. These results open up new biotechnological approaches to fight iron deficiency in crops.

  4. Secretion of Phy tosiderophore and Its Effects on Soil Fe Availability

    Institute of Scientific and Technical Information of China (English)

    SHIWEI-MING; LIUZHI-YU

    1991-01-01

    Large amounts of phytosiderophore are detected from both the solution and the rhizosphere soil when cereal crops are under Fe deficiency stress.The extension of phytosiderophore in the rhizosphere soil is found only within 1 mm apart from the root surface.The rate of phytosiderophore secretion is negatively related to chlorophyll content in young leaves and positively related to the Fe-solubilizing capacity.Results from in vitro experiments whow 10 μmoles mugineic acid can dissolve 501 μg Fe from iron hydroxide and 146 ug from strengite.Thus,phytosiderophore can considerably enhance the soil iron availability by increasing the solubility of amorphous iron hydroxide and iron phosphate,and active Fe is consequently accumulated in the plant rhizosphere,43% higher than in the bulk soils There is evidence to support that mugineic acid chelates with Fe%3+ at a rate of 1:1 in the acid condition.In addition,we observe mugineic acid has certain effects on mobilization of P as well as Fe by dissolving the insoluble iron phosphate,And phytosiderophore seems to be an effective remedy for the chlorosis of dicotyledonous plants.

  5. In vitro selection in resistance breeding of strawberry (Fragaria x ananassa duch.).

    Science.gov (United States)

    Zebrowska, Jadwiga Irena

    2010-01-01

    Genetic resistance to pathogenetic soil-borne fungus Verticillium dahliae Kleb. was examined in two strawberry somaclones. Strawberry somaclones were obtained in sterile culture from runner tips of cultivars 'Merton Dawn' and 'Selva'. In vitro selection was performed with the use of homogenate of liquid cultures of Verticillium dahliae. Microplants of both somaclones were inoculated at stage of 4. Leaves. Disease symptoms were observed at 15., 30., 45., 60. and 75. days post inoculation. Extent of leaf chlorosis was rated on a scale of 0-4. Under the controlled in vitro culture conditions a different response to infection by this pathogenic fungus was observed. After 75. days post inoculation the contribution of necrotic plants in somaclone of 'Merton Dawn' reached the value of 76%, whereas in somaclone of 'Selva' this value reached 86%. In control somaclones of 'Merton Dawn' and 'Selva' the contribution of necrotic plants after 75. days post mock-inoculation with sterile distilled water reached the considerably lower value of 13%. These results revealed that somaclone of 'Merton Dawn' was more genetically resistant to infection by V. dahliae than somaclone of 'Selva'. The observed response to in vitro infection caused by Verticillium dahliae in examined somaclones was similar in comparison with original cultivars. Furthermore, somaclonal variation induced in tissue cultured strawberry was sufficient to select variants that showed enhanced genetic resistance to Verticillium wilt caused by V. dahliae. In vitro selection can be efficiently used as an alternative program to conventional resistance breeding in strawberry. PMID:21534479

  6. Screening for Barley Waterlogging Tolerance in Nordic Barley Cultivars (Hordeum vulgare L. Using Chlorophyll Fluorescence on Hydroponically-Grown Plants

    Directory of Open Access Journals (Sweden)

    Nils-Ove Bertholdsson

    2013-04-01

    Full Text Available Waterlogging can reduce crop yield by 20%–50% or more, and lack of efficient selection methods is an obstacle in plant breeding. The methods currently used are mainly indices based on germination ability in Petri dishes and leaf chlorosis in plants grown in waterlogged soils. Cultivation in oxygen-depleted nutrient solution is the ultimate waterlogging system. Therefore methods based on root growth inhibition and on fluorescence in plant material hydroponically grown in oxygen-depleted solution were evaluated against data on biomass accumulation in waterlogged soils. Both traits were correlated with waterlogging tolerance in soil, but since it was easier to measure fluorescence, this method was further evaluated. A selection of F2 plants with high and low fluorescence revealed a small but significant screening effect in F3 plants. A test of 175 Nordic cultivars showed large variations in chlorophyll fluorescence in leaves from oxygen-stressed seedlings, indicating that adaptation to waterlogging has gradually improved over the past 40–50 years with the introduction of new cultivars onto the market. However, precipitation also increased during the period and new cultivars may have inadvertently been adapted to this while breeding barley for grain yield. The results suggest that the hydroponic method can be used for screening barley populations, breeding lines or phenotyping of populations in developing markers for quantitative trait loci.

  7. Banana and coconut in-vitro cultures for induced mutations studies

    International Nuclear Information System (INIS)

    Explants obtained from shoot tips of developing suckers of banana were found to be suitable materials for plantlet formation in vitro. Subculture of the shoots formed from the original explant can lead to regeneration of numerous shoots from a single sucker. The technique can be a practical method of propagation. Though a more rapid rate of multiplication is still to be desired the present rate is much faster than the maximum rate of sucker production obtained under natural conditions. The conditions which favor shoot formation were the addition of benzyladenine, the use of dextrose at 2% instead of 4%, and the use of either Murashige and Skoog or of Vacin and Went salt solution. Viable explants can be obtained from suckers irradiated up to 10 Kr. Survival and shoot formation are sometimes not adversely affected by irradiation. Chlorosis and reduction in plantlet size and unusual seedling characters were among the features observed in plantlets regenerated from irradiated tissues. Proliferations derived from the cotyledonary sheath in coconut embryos could be successfully subcultured. The initial and subsequent proliferations may appear as nodular growths. In continuous subculture a nodular growth may change over to a large mass with smooth surface. Cellular characteristics of the two types of growth are markedly different. (author)

  8. Calcium Mitigates Arsenic Toxicity in Rice Seedlings by Reducing Arsenic Uptake and Modulating the Antioxidant Defense and Glyoxalase Systems and Stress Markers

    Directory of Open Access Journals (Sweden)

    Anisur Rahman

    2015-01-01

    Full Text Available The effect of exogenous calcium (Ca on hydroponically grown rice seedlings was studied under arsenic (As stress by investigating the antioxidant and glyoxalase systems. Fourteen-day-old rice (Oryza sativa L. cv. BRRI dhan29 seedlings were exposed to 0.5 and 1 mM Na2HAsO4 alone and in combination with 10 mM CaCl2 (Ca for 5 days. Both levels of As caused growth inhibition, chlorosis, reduced leaf RWC, and increased As accumulation in the rice seedlings. Both doses of As in growth medium induced oxidative stress through overproduction of reactive oxygen species (ROS by disrupting the antioxidant defense and glyoxalase systems. Exogenous application of Ca along with both levels of As significantly decreased As accumulation and restored plant growth and water loss. Calcium supplementation in the As-exposed rice seedlings reduced ROS production, increased ascorbate (AsA content, and increased the activities of monodehydroascorbate reductase (MDHAR, dehydroascorbate reductase (DHAR, catalase (CAT, glutathione peroxidase (GPX, superoxide dismutase (SOD, and the glyoxalase I (Gly I and glyoxalase II (Gly II enzymes compared with seedlings exposed to As only. These results suggest that Ca supplementation improves rice seedlings tolerance to As-induced oxidative stress by reducing As uptake, enhancing their antioxidant defense and glyoxalase systems, and also improving growth and physiological condition.

  9. Overexpression of Arabidopsis VIT1 increases accumulation of iron in cassava roots and stems.

    Science.gov (United States)

    Narayanan, Narayanan; Beyene, Getu; Chauhan, Raj Deepika; Gaitán-Solis, Eliana; Grusak, Michael A; Taylor, Nigel; Anderson, Paul

    2015-11-01

    Iron is extremely abundant in the soil, but its uptake in plants is limited due to low solubility in neutral or alkaline soils. Plants can rely on rhizosphere acidification to increase iron solubility. AtVIT1 was previously found to be involved in mediating vacuolar sequestration of iron, which indicates a potential application for iron biofortification in crop plants. Here, we have overexpressed AtVIT1 in the starchy root crop cassava using a patatin promoter. Under greenhouse conditions, iron levels in mature cassava storage roots showed 3-4 times higher values when compared with wild-type plants. Significantly, the expression of AtVIT1 showed a positive correlation with the increase in iron concentration of storage roots. Conversely, young leaves of AtVIT1 transgenic plants exhibit characteristics of iron deficiency such as interveinal chlorosis of leaves (yellowing) and lower iron concentration when compared with the wild type plants. Interestingly, the AtVIT1 transgenic plants showed 4 and 16 times higher values of iron concentration in the young stem and stem base tissues, respectively. AtVIT1 transgenic plants also showed 2-4 times higher values of iron content when compared with wild-type plants, with altered partitioning of iron between source and sink tissues. These results demonstrate vacuolar iron sequestration as a viable transgenic strategy to biofortify crops and to help eliminate micronutrient malnutrition in at-risk human populations.

  10. Enhanced salt resistance in apple plants overexpressing a Malus vacuolar Na+/H+ antiporter gene is associated with differences in stomatal behavior and photosynthesis.

    Science.gov (United States)

    Li, Chao; Wei, Zhiwei; Liang, Dong; Zhou, Shasha; Li, Yonghong; Liu, Changhai; Ma, Fengwang

    2013-09-01

    High salinity is a major abiotic factor that limits crop production. The dwarfing apple rootstock M.26 is sensitive to such stress. To obtain an apple that is adaptable to saline soils, we transformed this rootstock with a vacuolar Na(+)/H(+) antiporter, MdNHX1. Differences in salt tolerance between transgenic and wild-type (WT) rootstocks were examined under field conditions. We also compared differences when 'Naganofuji No. 2' apple was grafted onto these transgenic or WT rootstocks. Plants on the transgenic rootstocks grew well during 60 d of mild stress (100 mM NaCl) while the WT exhibited chlorosis, inhibited growth and even death. Compared with the untreated control, the stomatal density was greater in both non-grafted and grafted WT plants exposed to 200 mM NaCl. In contrast, that density was significantly decreased in leaves from grafted transgenic plants. At 200 mM NaCl, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and chlorophyll contents were markedly reduced in the WT, whereas the declines in those values were only minor in similarly stressed transgenic plants. Therefore, we conclude that overexpressing plants utilize a better protective mechanism for retaining higher photosynthetic capacity. Furthermore, this contrast in tolerance and adaptability to stress is linked to differences in stomatal behavior and photosynthetic rates.

  11. Comparative Proteomic Analysis of Differential Responses of Pinus massoniana and Taxus wallichiana var. mairei to Simulated Acid Rain

    Directory of Open Access Journals (Sweden)

    Wen-Jun Hu

    2014-03-01

    Full Text Available Acid rain (AR, a serious environmental issue, severely affects plant growth and development. As the gymnosperms of conifer woody plants, Pinus massoniana (AR-sensitive and Taxus wallichiana var. mairei (AR-resistant are widely distributed in southern China. Under AR stress, significant necrosis and collapsed lesions were found in P. massoniana needles with remarkable yellowing and wilting tips, whereas T. wallichiana var. mairei did not exhibit chlorosis and visible damage. Due to the activation of a large number of stress-related genes and the synthesis of various functional proteins to counteract AR stress, it is important to study the differences in AR-tolerance mechanisms by comparative proteomic analysis of tolerant and sensitive species. This study revealed a total of 65 and 26 differentially expressed proteins that were identified in P. massoniana and T. wallichiana var. mairei, respectively. Among them, proteins involved in metabolism, photosynthesis, signal transduction and transcription were drastically down-regulated in P. massoniana, whereas most of the proteins participating in metabolism, cell structure, photosynthesis and transcription were increased in T. wallichiana var. mairei. These results suggest the distinct patterns of protein expression in the two woody species in response to AR, allowing a deeper understanding of diversity on AR tolerance in forest tree species.

  12. Exploitation of subabul stem lignin as a matrix in controlled release agrochemical nanoformulations: a case study with herbicide diuron.

    Science.gov (United States)

    Yearla, Srinivasa Rao; Padmasree, Kollipara

    2016-09-01

    The utilization of nanomaterials in the domain of agriculture is at an inception, especially in the development of controlled release agrochemical nanoformulations. The present study demonstrated the potential of subabul stem lignin as a matrix material in agrochemical formulations using nanotechnology. In this study, "nanoprecipitation" method was employed and "optimized" to fabricate a stable herbicide, "diuron nanoformulation" (DNF). "Optimized DNF" (ODNF) has 5.17 ± 0.49 % diuron loading efficiency (DLE) and 74.3 ± 4 % encapsulation efficiency (EE). The size of nanoparticles in ODNF was 166 ± 68 nm as revealed by FESEM/TEM studies. Physicochemical characterization of ODNF by UV, FT-IR, and DSC studies revealed the successful loading of diuron within the lignin matrix. The ODNF exhibited nonlinear biphasic release profile for diuron. Further, the bioefficacy of diuron released from ODNF was tested using canola (Brassica rapa). B. rapa seedlings grown in the soil supplemented with ODNF showed early signs of leaf chlorosis and mortality when compared with seedlings grown in the presence of commercial diuron formulation (CDF) or bulk diuron (BD), respectively. This study not only revealed the exploitation of subabul stem lignin as a "matrix" in the controlled release nanoformulation of diuron but also opened up new avenues for utilizing it as matrix for several other agrochemicals associated with the growth and development of the plant. PMID:27259957

  13. Plant ozone injury symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Nouchi, I.; Odaira, T.; Sawada, T.; Oguchi, K.; Komeiji, T.

    1973-01-01

    A study of the phytotoxicity of ozone to plants was conducted in controlled-atmosphere greenhouses to determine if the symptoms of such exposure would be similar to symptoms exhibited by plants exposed to photochemical smog (which contains ozone) in the Tokyo area. Test plants used were herbaceous plants and woody plants, which were fumigated to 20 pphm ozone. Plants used as controls for the oxone exposure experiments were placed in a carbon filtered greenhouse. Herbaceous plants were generally sensitive to injury, especially Brassica rapa, Brassica pekinensis and others were extremely responsive species. In comparison with herbaceous plants, woody plants were rather resistant except for poplar. Depending on plant species and severity of injury, ozone-injury symptoms of herbaceous plants were bleaching, chlorosis, necrosis, and red-dish-brown flecks. Leaves of woody plants developed discrete, punctate spots, reddish-brown pigment on the upper surfaces and lastly defoliation. Ozone injury was typically confined to the upper leaf surfaces and notably greater mature leaves. Microscopic examination showed that pallisade cells were much more prone to ozone injury than other tissues.

  14. Impact of copper toxicity on stone-head cabbage (Brassica oleracea var. capitata) in hydroponics.

    Science.gov (United States)

    Ali, Sajid; Shahbaz, Muhammad; Shahzad, Ahmad Naeem; Khan, Hafiz Azhar Ali; Anees, Moazzam; Haider, Muhammad Saleem; Fatima, Ammara

    2015-01-01

    Arable soils are frequently subjected to contamination with copper as the consequence of imbalanced fertilization with manure and organic fertilizers and/or extensive use of copper-containing fungicides. In the present study, the exposure of stone-head cabbage (Brassica oleracea var. capitata) to elevated Cu(2+) levels resulted in leaf chlorosis and lesser biomass yield at ≥2 µ M. Root nitrate content was not statistically affected by Cu(2+) levels, although it was substantially decreased at ≥5 µ M Cu(2+) in the shoot. The decrease in nitrate contents can be related to lower nitrate uptake rates because of growth inhibition by Cu-toxicity. Shoot sulfate content increased strongly at ≥2 µ M Cu(2+) indicating an increase in demand for sulfur under Cu stress. Furthermore, at ≥2 µM concentration, concentration of water-soluble non-protein thiol increased markedly in the roots and to a smaller level in the shoot. When exposed to elevated concentrations of Cu(2+) the improved sulfate and water-soluble non-protein thiols need further studies for the evaluation of their direct relation with the synthesis of metal-chelating compounds (i.e., phytochelatins).

  15. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development. PMID:27243585

  16. Interference of nickel with copper and iron homeostasis contributes to metal toxicity symptoms in the nickel hyperaccumulator plant Alyssum inflatum.

    Science.gov (United States)

    Ghasemi, Rasoul; Ghaderian, S Majid; Krämer, Ute

    2009-11-01

    The divalent cations of several transition metal elements have similar chemical properties and, when present in excess, one metal can interfere with the homeostasis of another. To better understand the role of interactions between transition metals in the development of metal toxicity symptoms in plants, the effects of exposure to excess nickel (Ni) on copper (Cu) and iron (Fe) homeostasis in the Ni hyperaccumulator plant Alyssum inflatum were examined. Alyssum inflatum was hypertolerant to Ni, but not to Cu. Exposure to elevated subtoxic Ni concentrations increased Cu sensitivity, associated with enhanced Cu accumulation and enhanced root surface Cu(II)-specific reductase activity. Exposure to elevated Ni concentrations resulted in an inhibition of root-to-shoot translocation of Fe and concentration-dependent progressive Fe accumulation in root pericycle, endodermis and cortex cells of the differentiation zone. Shoot Fe concentrations, chlorophyll concentrations and Fe-dependent antioxidant enzyme activities were decreased in Ni-exposed plants when compared with unexposed controls. Foliar Fe spraying or increased Fe supply to roots ameliorated the chlorosis observed under exposure to high Ni concentrations. These results suggest that Ni interferes with Cu regulation and that the disruption of root-to-shoot Fe translocation is a major cause of nickel toxicity symptoms in A. inflatum. PMID:19691676

  17. Changes in carbohydrate metabolism in coconut palms infected with the lethal yellowing phytoplasma.

    Science.gov (United States)

    Maust, B E; Espadas, F; Talavera, C; Aguilar, M; Santamaría, J M; Oropeza, C

    2003-08-01

    ABSTRACT Lethal yellowing (LY), a disease caused by a phytoplasma, is the most devastating disease affecting coconut (Cocos nucifera) in Mexico. Thousands of coconut palm trees have died on the Yucatan peninsula while plantations in Central America and on the Pacific coast of Mexico are severely threatened. Polymerase chain reaction assays enable identification of incubating palm trees (stage 0+, phytoplasma detected but palm asymptomatic). With the development of LY, palm trees exhibit various visual symptoms such as premature nut fall (stage 1), inflorescence necrosis (stages 2 to 3), leaf chlorosis and senescence (stages 4 to 6), and finally palm death. However, physiological changes occur in the leaves and roots prior to onset of visual symptoms. Stomatal conductance, photosynthesis, and root respiration decreased in stages 0+ to 6. The number of active photosystem II (PSII) reaction centers decreased during stage 2, but maximum quantum use efficiency of PSII remained similar until stage 3 before declining. Sugar and starch concentrations in intermediate leaves (leaf 14) and upper leaves (leaf 4) increased from stage 0- (healthy) to stages 2 to 4, while root carbohydrate concentrations decreased rapidly from stage 0- to stage 0+ (incubating phytoplasma). Although photosynthetic rates and root carbohydrate concentrations decreased, leaf carbohydrate concentrations increased, suggesting inhibition of sugar transport in the phloem leading to stress in sink tissues and development of visual symptoms of LY.

  18. Iron partitioning at an early growth stage impacts iron deficiency responses in soybean plants (Glycine max L.

    Directory of Open Access Journals (Sweden)

    Carla eSantos

    2015-05-01

    Full Text Available Iron (Fe deficiency chlorosis (IDC leads to leaf yellowing, stunted growth and drastic yield losses. Plants have been differentiated into ‘Fe-efficient’ (EF if they resist to IDC and ‘Fe-inefficient’ (IN if they do not, but the reasons for this contrasting efficiency remain elusive. We grew EF and IN soybean plants under Fe deficient and Fe sufficient conditions and evaluated if gene expression and the ability to partition Fe could be related to IDC efficiency. At an early growth stage, Fe-efficiency was associated with higher chlorophyll content, but Fe reductase activity was low under Fe-deficiency for EF and IN plants. The removal of the unifoliate leaves alleviated IDC symptoms, increased shoot:root ratio and trifoliate leaf area. EF plants were able to translocate Fe to the aboveground plant organs, whereas the IN plants accumulated more Fe in the roots. FRO2-like gene expression was low in the roots; IRT1-like expression was higher in the shoots; and ferritin was highly expressed in the roots of the IN plants. The efficiency trait is linked to Fe partitioning and the up-regulation of Fe-storage related genes could interfere with this key process. This work provides new insights into the importance of mineral partitioning among different plant organs at an early growth stage.

  19. Increasing early crops of unprotected tomatoes (Lycopersicon esculentum Mill. with naphthoxyacetic acid applied on whole plants

    Directory of Open Access Journals (Sweden)

    Krystyna Górecka

    2013-12-01

    Full Text Available A parthenocarpy-inducing preparation, Betokson, containing beta-naphthoxyacetic acid (NOA as an active ingredient, was applied by spraying whole plants. As one of the controls, dipping the trusses in NOA solution was used according to a currently recommended technique. NOA applied by each of these treatment increased the very early yield (first 4 pickings by 4-11 times in cv. Venture and 3-4 times in cv. New Yorker in comparison with the untreated controls. Treating the whole plant increased the very early yield more than did dipping the trusses. The early yield (first 8 pickings was also increased in cv. Venture by NOA applied by both methods. Treatments with NOA decreased, however, the late yield. This decline was more marked with the higher NOA concentration and when the whole-plant-spray was applied. Gibberellic acid (GA3 applied alone as a whole-plant-spray at a concentration of 25 mg·dm-3, did not increase the very early yield but in combination with NOA, increased the early yield in cv. New Yorker. GA3 alone, or in combination with NOA, applied as a spray on the whole plant caused marked chlorosis of the leaves and marked decline of the total yield.

  20. Influence of Sulfur Induced Stress on Oxidative Status and Antioxidative Machinery in Leaves of Allium cepa L.

    Science.gov (United States)

    Chandra, Neelam; Pandey, Nalini

    2014-01-01

    A pot culture experiment was carried out to assess the effect of sulfur stress on growth, oxidative status, and antioxidative metabolism. Onion plants were treated with three different levels of sulfur, namely, 1.0, 4.0, and 8.0 mM S L(-1). Plants raised with 4.0 mM S L(-1) represent sufficient growth for the best vegetative yield. Plants supplied with 1.0 and 8.0 mM S L(-1) showed retarded growth, chlorosis, and reduction in biomass and photoassimilatory pigments. Tissue sulfur concentration and cysteine were increased with increasing sulfur supply. Carbohydrates (sugars and starch) were accumulated in sulfur stressed plants. Hydrogen peroxide levels were increased in sulfur stressed plants. Thiobarbituric acid reactive substances levels were also increased which was an indicator of lipid peroxidation. Enzymatic (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase) and nonenzymatic (asorbate) antioxidative components were enhanced in sulfur stressed plants. Glutathione was increased with increasing sulfur supply. The present study showed that the adverse effects of inadequate sulfur supply result in irregular metabolic activities and antioxidant machinery. PMID:27379315

  1. Heavy metal toxicity in rice and soybean plants cultivated in contaminated soil

    Directory of Open Access Journals (Sweden)

    Maria Lígia de Souza Silva

    2014-04-01

    Full Text Available Heavy metals can accumulate in soil and cause phytotoxicity in plants with some specific symptoms. The present study evaluated the specific symptoms on rice and soybeans plants caused by excess of heavy metals in soil. Rice and soybean were grown in pots containing soil with different levels of heavy metals. A completely randomized design was used, with four replications, using two crop species and seven sample soils with different contamination levels. Rice and soybean exhibited different responses to the high concentrations of heavy metals in the soil. Rice plants accumulated higher Cu, Mn, Pb and Zn concentrations and were more sensitive to high concentrations of these elements in the soil, absorbing them more easily compared to the soybean plants. However, high available Zn concentrations in the soil caused phytotoxicity symptoms in rice and soybean, mainly chlorosis and inhibited plant growth. Further, high Zn concentrations in the soil reduced the Fe concentration in the shoots of soybean and rice plants to levels considered deficient.

  2. Genome Wide Association Mapping for the Tolerance to the Polyamine Oxidase Inhibitor Guazatine in Arabidopsis thaliana.

    Science.gov (United States)

    Atanasov, Kostadin E; Barboza-Barquero, Luis; Tiburcio, Antonio F; Alcázar, Rubén

    2016-01-01

    Guazatine is a potent inhibitor of polyamine oxidase (PAO) activity. In agriculture, guazatine is used as non-systemic contact fungicide efficient in the protection of cereals and citrus fruits against disease. The composition of guazatine is complex, mainly constituted by a mixture of synthetic guanidated polyamines (polyaminoguanidines). Here, we have studied the effects from exposure to guazatine in the weed Arabidopsis thaliana. We report that micromolar concentrations of guazatine are sufficient to inhibit growth of Arabidopsis seedlings and induce chlorosis, whereas germination is barely affected. We observed the occurrence of quantitative variation in the response to guazatine between 107 randomly chosen Arabidopsis accessions. This enabled us to undertake genome-wide association (GWA) mapping that identified a locus on chromosome one associated with guazatine tolerance. CHLOROPHYLLASE 1 (CLH1) within this locus was studied as candidate gene, together with its paralog (CLH2). The analysis of independent clh1-2, clh1-3, clh2-3, clh2-2, and double clh1-2 clh2-3 mutant alleles indicated that CLH1 and/or CLH2 loss-of-function or expression down-regulation promote guazatine tolerance in Arabidopsis. We report a natural mechanism by which Arabidopsis populations can overcome toxicity by the fungicide guazatine. PMID:27092150

  3. Lotus japonicus plants of the Gifu B-129 ecotype subjected to alkaline stress improve their Fe(2+) bio-availability through inoculation with Pantoea eucalypti M91.

    Science.gov (United States)

    Campestre, María Paula; Castagno, Luis Nazareno; Estrella, María Julia; Ruiz, Oscar Adolfo

    2016-03-15

    Inoculation assays with Pantoea eucalypti M91 were performed on Lotus japonicus ecotype Gifu. Under alkaline conditions, this ecotype is characterized by the development of interveinal chlorosis of the apical leaves due to low mobilization of Fe(2+). Inoculation with P. eucalypti M91, a plant growth-promoting bacterial strain capable of producing pyoverdine-like and pyochelin-like siderophores under alkaline growth conditions, alters the root, resulting in a herringbone pattern of root branching. Additional features include improvement in Fe(2+) transport to the shoots, acidification of the hydroponic solution of the plant cultures, and an accompanying increase in the efficiency of the PSII parameters. In addition, there was an increase in the expression of the FRO1 and IRT1 genes, accompanied by a significant increase in FRO activity. Results showed that P. eucalypti M91 has a beneficial effect on the Fe acquisition machinery of Strategy I, as described for non-graminaceous monocots and dicots, suggesting its potential as an inoculant for legume crops cultivated in alkaline soils. PMID:26815729

  4. Effect of cadmium stress on inductive enzymatic and nonenzymatic responses of ROS and sugar metabolism in multiple shoot cultures of Ashwagandha (Withania somnifera Dunal).

    Science.gov (United States)

    Mishra, Bhawana; Sangwan, Rajender S; Mishra, Smrati; Jadaun, Jyoti S; Sabir, Farzana; Sangwan, Neelam S

    2014-09-01

    Withania somnifera is one of the most important medicinal plant and is credited with various pharmacological activities. In this study, in vitro multiple shoot cultures were exposed to different concentrations (5-300 μM) of cadmium (Cd) as cadmium sulphate to explore its ability to accumulate the heavy metal ion and its impact on the metabolic status and adaptive responses. The results showed that supplemental exposure to Cd interfered with N, P, and K uptake creating N, P, and K deficiency at higher doses of Cd that also caused stunting of growth, chlorosis, and necrosis. The study showed that in vitro shoots could markedly accumulate Cd in a concentration-dependent manner. Enzymatic activities and isozymic pattern of catalase, ascorbate peroxidase, guaiacol peroxidase, peroxidase, glutathione-S-transferase, glutathione peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase were altered substantially under Cd exposure. Sugar metabolism was also markedly modulated under Cd stress. Various other parameters including contents of photosynthetic pigments, phenolics, tocopherol, flavonoids, reduced glutathione, nonprotein thiol, ascorbate, and proline displayed major inductive responses reflecting their protective role. The results showed that interplay of enzymatic as well as nonenzymatic responses constituted a system endeavor of tolerance of Cd accumulation and an efficient scavenging strategy of its stress implications.

  5. 几种类型甘蓝雄性不育的研究 与显性不育系的利用%Investigation of Different Types of Male Sterility and Application of Dominant Male Sterility in Cabbage

    Institute of Scientific and Technical Information of China (English)

    方智远; 刘玉梅; 杨丽梅; 王晓武; 庄木

    2001-01-01

    Several types of male sterility (MS) in cabbage were investigated. The results indicated that using male sterility in 81132 controlled by a recessive gene only 50% male sterile plants can be achieved. Nigra cytoplasmic male sterility in CMSn78091 is associated with small nectar glands and un-fully opened flowers. Radish cytoplasmic male sterility in R1cc409 has problems of poor seed setting and chlorosis at low temperature. It is difficult to apply these three materials in cabbage breeding. Male sterile material CMSR29551 with improved radish male sterile cytoplasm has very stable male sterility and no problem of chlorosis at low temperatures. Several MS lines were developed after backcrossing it with different inbred lines. However,it was found that after several generations of backcrossing,hybrid vigor of the male sterile lines decreased,which limited its application in practical breeding. Male sterile line CMSR3625 with another improved radish cytoplasm has not only promising plant growth,flowering and seed setting characteristics,but also high combining ability. It showed good prospect in cabbage breeding. Male sterility controlled by dominant male sterile gene has perfect economic characteristics and male sterility. Two hybrids,which have passed the test of Committee of National Agricultural Variety Examination and Approving, were developed.%隐性不育材料83121ms,不育株率仅50%。黑芥胞质不育材料CMSN78091不育花不能完全开放,蜜腺小。萝卜胞质不育材料CMSR1409等及其转育后代开花结实性状不良,且低温下叶色黄化,以上3类不育材料在甘蓝实际育种中应用困难。改良的萝卜胞质不育材料CMSR29551等及其转育后代低温下叶色不黄化,在其转育后代中筛选出几份开花结实性状较好的不育系,但多代回交后不育系配制的F1杂种优势弱,应用有局限性。改良的萝卜胞质不育系CMSR3625等,植株性状、开花结实特性

  6. The role of micronutrients in crop production and human health

    International Nuclear Information System (INIS)

    The soils in Pakistan across 22 Mha cultivated area are predominantly alluvial and loessal, alkaline in pH, calcareous and low in organic matter. These factors are mainly responsible for nutrient fixation in soil and low availability to plants. Zinc (Zn) deficiency in Pakistan was the first micro nutrient disorder recognised in early 1970s as a cause of hadda disease in rice. After identification of Zn deficiency, extensive research has been carried out during last four decades on micro nutrient deficiencies in soils and their drastic effects on crops. Subsequently, field-scale deficiencies of zinc (Zn) boron (B) and iron (Fe) have been established in many field and horticultural crops. The most widespread deficiency is of Zn as 70 % of the soils of Pakistan are Zn deficient and observed in rice, wheat, cotton, maize, sunflower, sugarcane, brassica, potato and in many other crops along with citrus and deciduous fruits. Boron deficiency is another major nutritional disorder which severely affects rice, cotton, wheat, sugarbeet, peanut, citrus and deciduous fruits. The third field-scale disorder is Fe chlorosis which has been exhibited in peanut, chickpea, cotton, citrus, ornamentals and many tree species. Copper (Cu) and manganese (Mn) deficiencies are of localized occurrence. The mineral elements like Zn, Fe and Cu are as crucial for human health as organic compounds such as carbohydrates, fats, protein and vitamins. The daily dietary intake of young adult ranges from 10-60 mg for Fe, 2-3 mg for Cu and 15 mg for Zn. Intake less than these values can cause slow physiological processes. These micronutrients deficiencies in soil are not only hampering the crop productivity but also are deteriorating produce quality. High consumption of cereal based foods with low contents of micronutrients is causing health hazards in humans. The contents of micronutrients in food can be elevated either by supplementation, fortification or by agricultural strategies i.e., bio

  7. Effects of zinc smelter emissions on farms and gardens at Palmerton, PA

    Science.gov (United States)

    Chaney, R.L.; Beyer, W.N.; Gifford, C.H.; Sileo, L.

    1988-01-01

    In 1979, before the primary Zn smelter at Palmerton was closed due to excessive Zn and Cd emissions and change in the price of Zn, we were contacted by a local veterinarian regarding death of foals (young horses) on farms near the smelter. To examine whether Zn or Cd contamination of forage or soils could be providing potentially toxic levels of Zn or other elements in the diets of foals, we measured metals in forages, soils, and feces of grazing livestock on two farms near Palmerton. The farms were about 2.5 and about 10 km northeast of the East stack. Soils, forages, and feces were greatly increased in Zn and Cd. Soil, forage, and fecal Zn were near 1000 mg/kg and Cd, 10-20 mg/kg at farm A (2.5 km) compared to normal background levels of 43 mg Zn and 0.2 mg Cd/kg, respectively. Liver and kidney of cattle raised on Farm A were increased in Zn and Cd, indicating that at least part of the Zn and Cd in smelter contaminated forages was bioavailable. During the farm sampling, we obtained soil from one garden in Palmerton within 200 m of the primary (West) smelter. The Borough surrounds the smelter facility in a valley. Because soil Cd was near 100 mg/kg, we sampled garden soils and vegetables from over 40 gardens in 6 randomly selected blocks and in rural areas at different distances from the smelter during September, 1980. All homes were contacted on each sampled block. Nearly all homes had some garden, while at least 2 appeared to grow over 50% of their annual vegetable and potato consumption. Palmerton garden soils averaged 76 mg Cd/kg and 5830 mg Zn/kg. Gardeners had been taught to add limestone and organic fertilizers to counteract yield reduction and chlorosis due to the excessive soil Zn. Gardens with over 5000 mg Zn/kg were nearly allover pH 7, and many were calcareous. Because the smelter had not yet ceased operations in 1980, crops could have been polluted by aerosol Zn and Cd emitted by the smelter. Crop Zn and Cd were extremely high, about 100 times normal

  8. Cadmium tolerance and accumulation characteristics of mature flax, cv. Hermes: Contribution of the basal stem compared to the root

    Energy Technology Data Exchange (ETDEWEB)

    Douchiche, Olfa, E-mail: olfa.douchiche@hotmail.fr [Laboratory Glyco-MEV EA 4358, IFRMP 23, University of Rouen, 76821 Mont Saint Aignan Cedex (France); Laboratory Biologie et Physiologie Cellulaires Vegetales, Department of Biology, University of Tunis, 1060 Tunis (Tunisia); Chaiebi, Wided [Laboratory Biologie et Physiologie Cellulaires Vegetales, Department of Biology, University of Tunis, 1060 Tunis (Tunisia); Morvan, Claudine, E-mail: claudine.morvan@univ-rouen.fr [Laboratory PBS-UMR 6270 CNRS, FR 3038, University of Rouen, 76821 Mont Saint Aignan Cedex (France)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Cd accumulated in stem bottom part exceeded the defined hyperaccumulator threshold. Black-Right-Pointing-Pointer No toxic symptoms occurred and TI of all growth parameters ranged between 0.7 and 1. Black-Right-Pointing-Pointer The high level of Zn, Mn and Cu may contribute to the absence of chlorosis in stem. Black-Right-Pointing-Pointer Cd/Ca synergistic effect observed in the stem may alleviate Cd toxicity. Black-Right-Pointing-Pointer Hermes variety accumulated more Cd than the other flax varieties ever described. - Abstract: The potential of mature flax plants (cv. Hermes) to tolerate and accumulate cadmium (Cd) was studied to determine which part of the plant would be the key organ for phytoremediation purposes. After 4 month-growth on sand substrate containing 0.1 mM Cd in a greenhouse, the roots and stems were separated and the stems were divided into three parts. The effects of Cd were studied on growth parameters, histology and mineral nutrition. No visible toxic symptoms were observed. Tolerance-index values calculated from growth parameters and nutrients remained relatively high, allowing the development of the plant until maturity and formation of seeds. The roots and bottom stem accumulated the highest quantity of Cd (750 and 360 mg/kg dry matter), values which largely exceeded the threshold defined for hyperaccumulators. On the other hand, basal stem had a high bioconcentration factor (BCF = 32) and translocation factor TF Prime (2.5) but a low TF (0.5), indicating that this basal part would play a major role in phytoremediation (phytostabilization rather than phytorextraction). Therefore, the high tolerance to Cd and accumulation capacity make possible to grow Hermes flax on Cd-polluted soils.

  9. Symplastic phloem loading in poplar.

    Science.gov (United States)

    Zhang, Cankui; Han, Lu; Slewinski, Thomas L; Sun, Jianlei; Zhang, Jing; Wang, Zeng-Yu; Turgeon, Robert

    2014-09-01

    Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evidence suggests that sugar migrates passively through plasmodesmata from mesophyll cells into the sieve elements. The possibility of alternate loading mechanisms has important ramifications for the regulation of phloem transport and source-sink interactions. Here, we provide experimental evidence that, in gray poplar (Populus tremula × Populus alba), Suc enters the phloem through plasmodesmata. Transgenic plants were generated with yeast invertase in the cell walls to prevent Suc loading by this route. The constructs were driven either by the constitutive 35S promoter or the minor vein-specific galactinol synthase promoter. Transgenic plants grew at the same rate as the wild type without symptoms of loading inhibition, such as accumulation of carbohydrates or leaf chlorosis. Rates of photosynthesis were normal. In contrast, alfalfa (Medicago sativa) plants, which have limited numbers of plasmodesmata between mesophyll and phloem, displayed typical symptoms of loading inhibition when transformed with the same DNA constructs. The results are consistent with passive loading of Suc through plasmodesmata in poplar. We also noted defense-related symptoms in leaves of transgenic poplar when the plants were abruptly exposed to excessively high temperatures, adding to evidence that hexose is involved in triggering the hypersensitive response. PMID:25056922

  10. Impacts of ambient salinity and copper on brown algae: 1. Interactive effects on photosynthesis, growth, and copper accumulation.

    Science.gov (United States)

    Connan, Solène; Stengel, Dagmar B

    2011-07-01

    The effect of copper enrichment and salinity on growth, photosynthesis and copper accumulation of two temperate brown seaweeds, Ascophyllum nodosum and Fucus vesiculosus, was investigated in laboratory experiments. A significant negative impact of reduced salinity on photosynthetic activity and growth was observed for both species. After 15 days at a salinity of 5, photosynthesis of A. nodosum was entirely inhibited and growth ceased at a salinity of 15. Increased copper concentration negatively affected photosynthetic activity of A. nodosum and F. vesiculosus resulting in chlorosis and reduced seaweed growth; 5 mg L⁻¹ copper caused an inhibition of the photosynthesis and the degradation of seaweed tips. Under reduced salinity, copper toxicity was enhanced and caused an earlier impact on the physiology of seaweed tips. After exposure to copper and different salinities for 15 days, copper contents of seaweeds were closely related to copper concentration in the water; seaweed copper contents reached their maximum after 1 day of exposure; contents only increased again when additional, free copper was added to the water. At high water copper concentrations or low salinity, or a combination of both, copper content of A. nodosum decreased. By contrast, copper content of F. vesiculosus increased, suggesting that different binding sites or uptake mechanisms exist in the two species. The results suggest that when using brown seaweeds in biomonitoring in situ, any change in the environment will directly and significantly affect algal physiology and thus their metal binding capacity; the assessment of the physiological status of the algae in combination with the analysis of thallus metal content will enhance the reliability of the biomonitoring process. PMID:21549661

  11. Hydrogen sulphide improves adaptation of Zea mays seedlings to iron deficiency.

    Science.gov (United States)

    Chen, Juan; Wu, Fei-Hua; Shang, Yu-Ting; Wang, Wen-Hua; Hu, Wen-Jun; Simon, Martin; Liu, Xiang; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2015-11-01

    Hydrogen sulphide (H2S) is emerging as a potential molecule involved in physiological regulation in plants. However, whether H2S regulates iron-shortage responses in plants is largely unknown. Here, the role of H2S in modulating iron availability in maize (Zea mays L. cv Canner) seedlings grown in iron-deficient culture solution is reported. The main results are as follows: Firstly, NaHS, a donor of H2S, completely prevented leaf interveinal chlorosis in maize seedlings grown in iron-deficient culture solution. Secondly, electron micrographs of mesophyll cells from iron-deficient maize seedlings revealed plastids with few photosynthetic lamellae and rudimentary grana. On the contrary, mesophyll chloroplasts appeared completely developed in H2S-treated maize seedlings. Thirdly, H2S treatment increased iron accumulation in maize seedlings by changing the expression levels of iron homeostasis- and sulphur metabolism-related genes. Fourthly, phytosiderophore (PS) accumulation and secretion were enhanced by H2S treatment in seedlings grown in iron-deficient solution. Indeed, the gene expression of ferric-phytosiderophore transporter (ZmYS1) was specifically induced by iron deficiency in maize leaves and roots, whereas their abundance was decreased by NaHS treatment. Lastly, H2S significantly enhanced photosynthesis through promoting the protein expression of ribulose-1,5-bisphosphate carboxylase large subunit (RuBISCO LSU) and phosphoenolpyruvate carboxylase (PEPC) and the expression of genes encoding RuBISCO large subunit (RBCL), small subunit (RBCS), D1 protein (psbA), and PEPC in maize seedlings grown in iron-deficient solution. These results indicate that H2S is closely related to iron uptake, transport, and accumulation, and consequently increases chlorophyll biosynthesis, chloroplast development, and photosynthesis in plants.

  12. Two iron-regulated transporter (IRT) genes showed differential expression in poplar trees under iron or zinc deficiency.

    Science.gov (United States)

    Huang, Danqiong; Dai, Wenhao

    2015-08-15

    Two iron-regulated transporter (IRT) genes were cloned from the iron chlorosis resistant (PtG) and susceptible (PtY) Populus tremula 'Erecta' lines. Nucleotide sequence analysis showed no significant difference between PtG and PtY. The predicted proteins contain a conserved ZIP domain with 8 transmembrane (TM) regions. A ZIP signature sequence was found in the fourth TM domain. Phylogenetic analysis revealed that PtIRT1 was clustered with tomato and tobacco IRT genes that are highly responsible to iron deficiency. The PtIRT3 gene was clustered with the AtIRT3 gene that was related to zinc and iron transport in plants. Tissue specific expression indicated that PtIRT1 only expressed in the root, while PtIRT3 constitutively expressed in all tested tissues. Under iron deficiency, the expression of PtIRT1 was dramatically increased and a significantly higher transcript level was detected in PtG than in PtY. Iron deficiency also enhanced the expression of PtIRT3 in PtG. On the other hand, zinc deficiency down-regulated the expression of PtIRT1 and PtIRT3 in both PtG and PtY. Zinc accumulated significantly under iron-deficient conditions, whereas the zinc deficiency showed no significant effect on iron accumulation. A yeast complementation test revealed that the PtIRT1 and PtIRT3 genes could restore the iron uptake ability under the iron uptake-deficiency condition. The results will help understand the mechanisms of iron deficiency response in poplar trees and other woody species.

  13. Caracterización de los lepidópteros fitófagos asociados a la herbivoría de frailejones en la microcuenca de la quebrada Calostros del Parque Nacional Natural Chingaza

    Directory of Open Access Journals (Sweden)

    Cristian Salinas

    2013-06-01

    Full Text Available The paramo ecosystem is one of the most sensitive to changes in climate and land use. These changes in physical conditions may lead to changes in species composition and their life cycles, increasing susceptibility to attack by pathogens and other species that seize the opportunity to colonize new niches. The “frailejon”, Espeletia sp., is a keystone species of the páramo, but herbivory due to phytophagous insects and fungi has recently led to the death of a large number of frailejones. The knowledge of the biology and the effect of insects on such plants contribute to decision making related to environmental management, monitoring, sustainable management and ecosystem preservation. This study was conducted in the watershed of the Calostros creek, Chingaza National Park, Colombia, in order to determine the magnitude of Lepidoptera insect damage inflicted on vegetative structures of individuals of the genus Espeletia sp., and examine whether the symptoms and the degree of insect damage varies between plants from different elevations. For this purpose, 30 Espeletia plants were monitored bi-monthly over a period of six months. We observed three species of Lepidoptera larvae capable of causing damage to Espeletia sp. However only one species, Hellinsia sp., is widely distributed and is able to cause severe damage to frailejones, primarily to the apical meristem of plants. The pathology caused by Hellinsia sp. Includes tissue loss, severe chlorosis and leaf curling. Finally, it was observed that individuals of Espeletia sp have the ability to continue normal development after being hosts of larval Hellinsia sp.

  14. Shoot multiplication and plant regeneration in Caragana fruticosa (Pall.) Besser

    Institute of Scientific and Technical Information of China (English)

    ZHAI Xiao-jie; YANG Ling; SHEN Hai-long

    2011-01-01

    Different nutrient media can affectin vitro culturing protocols,and experimentation under varied growth conditions is valuable in plants where in vitro methods are in preliminary stages.We carried out the first in vitro propagation studies for the endangered species Caragana fruticosa (Fabaceae).We evaluated various nutrient media for their inpact on shoot elongation and axillary bud proliferation using different concentrations of 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA).Shoot elongation was evaluated based on adventitious shoot primary culture and subculture regeneration from Caragana seedlings.Our goal was to improve both micropropagation and regeneration in C.fruticosa.MS nutrient media was superior to 1/2MS macronutrients,DKW,QL,and WPM for shoot elongation and axillary shoot proliferation.Shoots grown on 1/2MS and WPM exhibited some chlorosis,and shoots on QL produced larger leavers than plants growing on normal medium.The shoot proliferation coefficient on MS media supplemented with 2.22 μM BA and 0.44 μM BA + 2.69 μM NAA was significantly higher than that with other treatments in the primary culture.Shoots on 2.22 μM BA showed a higher proliferation coefficient (3.17) than others in the subculture.Shoots were rooted on 1/2MS medium with the addition of different concentrations of NAA.The optimal concentration for rooting was 0.27 μM NAA (74%).Roots exhibited many stout and long root hairs.Survivl of established plantlets was 82% at 30 days after transfer to soil.Plants established in the green house showed normal growth and displayed no apparent morphological differences compared to stock plants.

  15. The 1981-1982 NCLAN (National Crop Loss Assessment Network) program at LLNL: The effects of ozone and sulfur dioxide, singly and in combination, on field-grown tomato

    Energy Technology Data Exchange (ETDEWEB)

    Surano, K.A.; Mutters, R.G.; Temple, P.J.; Bingham, G.E.; Kercher, J.R.; Shinn, J.H.

    1987-07-01

    The combined effects of ozone (O/sub 3/) and sulfur dioxide (SO/sub 2/) exposures on tomato (Lycopersicon esculentum Mill.) crop yields were measured during the 1981 and 1982 growing seasons. The effort, part of the National Crop Loss Assessment Network (NCLAN), had the objective of determining the yield dose response of tomato grown under commercial conditions. Dose response was determined using step-wise multiple regression techniques and was expressed as reduction in marketable yield as a function of increased pollutant levels. The crops were harvested during mid-September 1981 and during mid-October 1982. No O/sub 3/- or So/sub 2/-induced visible injury symptons (lesions, chlorosis, or becrosis) were apparent on foliage or fruits. Total marketable fruit fresh weight was used as the dependent variable in the regression analysis because it most closely represented the economic value of the crop. Comparison of chambered- and companion-plot data showed that the chambers themselves caused significant effects on the crop. Yields were reduced 12% in 1981 and 24% in 1982 due to the chambers. There was also more unripened fruit within the chambers because of chamber-induced uneven distribution of an aerially-applied ripening agent. Dose-response results were independent of the chamber effects. Based on companion-plot data, the yield of the crop in the research area was 65/plus minus/2 Mg ha/sup /minus/1/ in both years. The research-area yields correlated well with those from the adjacent commercial plantation. With respect to tomato production in the San Joaquin Valley, we recommend that an air quality management strategy be adopted to contain ambient O/sub 3/ concentrations at or below present levels. Containment at present levels would avoid O/sub 3/-induced tomato yield reductions greater than 7%, even during atypical years such as 1982. 26 refs., 17 figs., 9 tabs.

  16. Fusaric acid accelerates the senescence of leaf in banana when infected by Fusarium.

    Science.gov (United States)

    Dong, Xian; Xiong, Yinfeng; Ling, Ning; Shen, Qirong; Guo, Shiwei

    2014-04-01

    Fusarium oxysporum f.sp. cubense (FOC) is a causal agent of vascular wilt and leaf chlorosis of banana plants. Chloroses resulting from FOC occur first in the lowest leaves of banana seedlings and gradually progress upward. To investigate the responses of different leaf positions to FOC infection, hydroponic experiments with FOC inoculation were conducted in a greenhouse. Fusarium-infected seedlings exhibited a decrease in net photosynthesis rate, stomatal conductance, and transpiration rate of all leaves. The wilting process in Fusarium-infected seedlings varied with leaf position. Measurements of the maximum photochemical efficiency of photosystem II (F(V)/F(max) and visualization with transmission electron microscopy showed a positive correlation between chloroplast impairment and severity of disease symptoms. Furthermore, results of malondialdehyde content and relative membrane conductivity measurements demonstrated that the membrane system was damaged in infected leaves. Additionally, the activities of phenylalanine ammonia-lyase, peroxidase and polyphenol oxidase were increased and total soluble phenolic compounds were significantly accumulated in the leaves of infected plants. The structural and biochemical changes of infected plants was consistent with plant senescence. As the FOC was not detected in infected leaves, we proposed that the chloroplast and membrane could be damaged by fusaric acid produced by Fusarium. During the infection, fusaric acid was first accumulated in the lower leaves and water-soluble substances in the lower leaves could dramatically enhance fusaric acid production. Taken together, the senescence of infected banana plants was induced by Fusarium infection with fusaric acid production and the composition of different leaf positions largely contribute to the particular senescence process.

  17. Degradation of phycobilisomes in Synechocystis sp. PCC6803: evidence for essential formation of an NblA1/NblA2 heterodimer and its codegradation by A Clp protease complex.

    Science.gov (United States)

    Baier, Antje; Winkler, Wiebke; Korte, Thomas; Lockau, Wolfgang; Karradt, Anne

    2014-04-25

    When cyanobacteria acclimate to nitrogen deficiency, they degrade their large (3-5-MDa), light-harvesting complexes, the phycobilisomes. This massive, yet specific, intracellular degradation of the pigmented phycobiliproteins causes a color change of cyanobacterial cultures from blue-green to yellow-green, a process referred to as chlorosis or bleaching. Phycobilisome degradation is induced by expression of the nblA gene, which encodes a protein of ~7 kDa. NblA most likely acts as an adaptor protein that guides a Clp protease to the phycobiliproteins, thereby initiating the degradation process. Most cyanobacteria and red algae possess just one nblA-homologous gene. As an exception, the widely used "model organism" Synechocystis sp. PCC6803 expresses two such genes, nblA16803 and nblA26803, both of whose products are required for phycobilisome degradation. Here, we demonstrate that the two NblA proteins heterodimerize in vitro and in vivo using pull-down assays and a Förster energy-transfer approach, respectively. We further show that the NblA proteins form a ternary complex with ClpC (the HSP100 chaperone partner of Clp proteases) and phycobiliproteins in vitro. This complex is susceptible to ATP-dependent degradation by a Clp protease, a finding that supports a proposed mechanism of the degradation process. Expression of the single nblA gene encoded by the genome of the N2-fixing, filamentous cyanobacterium Nostoc sp. PCC7120 in the nblA1/nblA2 mutant of Synechocystis sp. PCC6803 induced phycobilisome degradation, suggesting that the function of the NblA heterodimer of Synechocystis sp. PCC6803 is combined in the homodimeric protein of Nostoc sp. PCC7120.

  18. Caracterização da comunidade bacteriana endofítica de citros por isolamento, PCR específico e DGGE Characterization of the endophytic bacterial community from citrus by isolation, specific PCR and DGGE

    Directory of Open Access Journals (Sweden)

    Paulo Teixeira Lacava

    2006-04-01

    Full Text Available O objetivo deste trabalho foi caracterizar a comunidade bacteriana endofítica de plantas assintomáticas (escapes e afetadas pela clorose variegada dos citros (CVC por meio de isolamento em meio de cultura, técnica de gradiente desnaturante em gel de eletroforese (DGGE e detecção de Methylobacterium mesophilicum e Xyllela fastidiosa por meio de PCR específico, para estudar esta comunidade e sua relação com a ocorrência da CVC. A análise da comunidade bacteriana via DGGE permitiu a detecção de X. fastidiosa, bem como Klebsiella sp. e Acinetobacter sp. como endófitos de citros. Foram observados também Curtobacterium sp., Pseudomonas sp., Enterobacter sp. e Bacillus spp. Utilizando primers específicos, Methylobacterium mesophilicum e X. fastidiosa também foram observadas, reforçando hipóteses de que estas bactérias podem estar interagindo no interior da planta hospedeira.The aim of this work was to characterize endophytic bacterial community of assintomatic (escape and Citrus Variegated Chlorosis (CVC-affected citrus plants using isolation in culture medium, denaturing gradient gel electrophoresis (DGGE technique and Methylobacterium mesophilicum as well as Xylella fastidiosa specific PCR, allowing to assess this community and its interactions with CVC. The study of bacterial community by DGGE analysis allowed the detection of X. fastidiosa, as well as Klebsiella sp. e Acinetobacter sp., which were not detected previously. Curtobacterium sp., Pseudomonas sp., Enterobacter sp. and Bacillus spp. were also observed as endophyte in citrus plants. Using specific primers Methylobacterium mesophilicum and X. fastidiosa were observed, reinforcing that these bacteria could interact inside the host plant.

  19. Use of mutants to study host/pathogen relations

    International Nuclear Information System (INIS)

    Forty-six mutants with changed reactions in powdery mildew resistance were selected after EMS treatment of seeds from three cultivars of spring barley. Recently, further experiments for the induction of new mutants were successfully run with EMS again and with sodium azide (NaN3); but no mutants were obtained in the same experiment after application of sublethal doses of N-methyl-N'-nitro-N-nitrosoguanidine. The original cultivars were characterized by a medium grade of resistance in the field. Mutations were expected to be of major and monogenic effect and consequently to be primarily race-specific in nature. A detailed analysis of resistance was started, both in the field and under spore-proof conditions of environment-controlled growth cabinets. In the field, the progress of disease was recorded during three summer periods on an individual plant basis. Specific mutants were clearly identified by their changed reactions to the natural epidemics, i.e. by (a) lower or (b) higher susceptibility; by (c) adult plant, or (d) by young plant resistance. Degrees of chlorosis or necrosis were estimated on the infected leaves and the influence of the attack on yield components was studied. By controlled infections with eight different isolates of mildew, race-specificity of resistance reactions was determined for all the 46 mutants. The results were unexpected in that they did not show clear-cut vertical relations between mutants and single pathogen races. In some instances, the general level of resistance appeared to be shifted from the original medium level to higher or lower degrees; in other cases, increase of severity of attack was recorded with some pathotypes and decrease with others on the same mutant host

  20. Physiological and biochemical mechanisms preventing Cd-toxicity in the hyperaccumulator Atriplex halimus L.

    Science.gov (United States)

    Mesnoua, Mohammed; Mateos-Naranjo, Enrique; Barcia-Piedras, José María; Pérez-Romero, Jesús Alberto; Lotmani, Brahim; Redondo-Gómez, Susana

    2016-09-01

    The xero-halophyte Atriplex halimus L., recently described as Cd-hyperaccumulator, was examined to determine Cd toxicity threshold and the physiological mechanisms involved in Cd tolerance. An experiment was conducted to investigate the effect of cadmium from 0 to 1350 μM on chlorophyll fluorescence parameters, gas exchange, photosynthetic pigment concentrations and antioxidative enzyme activities of A. halimus. Cadmium, calcium, iron, manganese, magnesium, potassium, phosphorous, sodium and zinc concentrations were also analyzed. Plants of A. halimus were not able to survive at 1350 μM Cd and the upper tolerance limit was recorded at 650 μM Cd; although chlorosis was observed from 200 μM Cd. Cadmium accumulation increased with increase in Cd supply, reaching maxima of 0.77 and 4.65 mg g(-1) dry weight in shoots and roots, respectively, at 650 μM Cd. Dry mass, shoot length, specific leaf area, relative growth rate, net photosynthetic rate, stomatal conductance, pigments contents and chlorophyll fluorescence were significantly reduced by increasing Cd concentration. However, the activities of superoxide dismutase (SOD; EC1.15.1.1), catalase (CAT; EC1.11.1.6) and guaiacol peroxidase (GPx; EC1.11.1.7) were significantly induced by Cd. Exposures to Cd caused also a significant decrease in P contents in roots, Mg and Mn contents in shoots and Fe and K contents in roots and shoots and had no effect on Ca, Na and Zn contents. The tolerance of A. halimus to Cd stress might be related with its capacity to avoid the translocation of great amounts of Cd in its aboveground tissues and higher activities of enzymatic antioxidants in the leaf. PMID:27135816

  1. Arabidopsis plastid AMOS1/EGY1 integrates abscisic acid signaling to regulate global gene expression response to ammonium stress

    KAUST Repository

    Li, Baohai

    2012-10-12

    Ammonium (NH4 +) is a ubiquitous intermediate of nitrogen metabolism but is notorious for its toxic effects on most organisms. Extensive studies of the underlying mechanisms of NH4 + toxicity have been reported in plants, but it is poorly understood how plants acclimate to high levels of NH4 +. Here, we identified an Arabidopsis (Arabidopsis thaliana) mutant, ammonium overly sensitive1 (amos1), that displays severe chlorosis under NH4 + stress. Map-based cloning shows amos1 to carry a mutation in EGY1 (for ethylene-dependent, gravitropism-deficient, and yellow-green-like protein1), which encodes a plastid metalloprotease. Transcriptomic analysis reveals that among the genes activated in response to NH4 +, 90% are regulated dependent on AMOS1/ EGY1. Furthermore, 63% of AMOS1/EGY1-dependent NH4 +-activated genes contain an ACGTG motif in their promoter region, a core motif of abscisic acid (ABA)-responsive elements. Consistent with this, our physiological, pharmacological, transcriptomic, and genetic data show that ABA signaling is a critical, but not the sole, downstream component of the AMOS1/EGY1-dependent pathway that regulates the expression of NH4 +-responsive genes and maintains chloroplast functionality under NH4 + stress. Importantly, abi4 mutants defective in ABA-dependent and retrograde signaling, but not ABA-deficient mutants, mimic leaf NH4 + hypersensitivity of amos1. In summary, our findings suggest that an NH4 +-responsive plastid retrograde pathway, which depends on AMOS1/EGY1 function and integrates with ABA signaling, is required for the regulation of expression of the presence of high NH4 + levels. © 2012 American Society of Plant Biologists. All Rights Reserved.

  2. Influência do manganês sobre a nutrição mineral e crescimento da pimenteira do reino (Piper nigrum, L. Effect of manganese on mineral nutrition and growth of black pepper (Piper nigrum, L.

    Directory of Open Access Journals (Sweden)

    C.A.C. Veloso

    1995-08-01

    Full Text Available A pimenteira do reino (Piper nigrum, L. vem sendo cultivada em sua maior parte em solos com acidez elevada e balia saturação por bases. O manganês em condições de alta acidez pode provocar toxidez às plantas. Visando estudar os efeitos do manganês nessa cultura foi conduzido um experimento com a cultivar Guajarina em solução nutritiva, O manganês foi fornecido nas concentrações de 0; 10; 20; 30; 40 e 50 mg/L. Na ausência do elemento foram observados sintomas de deficiência e redução no crescimento. O excesso de manganês (30 mg/L na solução nutritiva reduziu o desenvolvimento das plantas e a absorção de P, K, Ca, Mg, Cu, Fe e ZN. Observaram-se sintomas de toxidez de manganês a partir da concentração de 20 mg/L, caracterizados por cloróse e pontos necróticos nas folhas.Black pepper (Piper nigrum, L. is usually grown in soils of low natural fertility and high acidity. Under such conditions manganese can cause toxicity to plants. An experiment using young plants of the cultivar Guajarina grown in nutrient solution was carried out in order to verify the effects of rates of manganese on this crop. The manganese was supplied at the concentrations of 0, 10, 20, 30, 40 and 50 mg/L. Excess of manganese (30 mg/L in the nutrient solution caused a reduction in growth and in the uptake of P, K, Ca, Mg, Cu, Fe and Zn. Toxicity symptoms were chlorosis and necrotic dots in the leaves, when the level of supply was 20 mg/L or higher.

  3. Effects of Ni2+ toxicity on Hill reaction and membrane functionality in maize

    Directory of Open Access Journals (Sweden)

    Ghasemi F.

    2012-11-01

    Full Text Available Soil contamination with heavy metals has become a worldwide problem, leading to losses in agricultural yield and hazardous health effects as they enter the food chain . Nickel as an essential trace element, affect a number of biochemical and physiological processes in plants in toxic levels. The most common symptoms are chlorosis, and inhibited photosynthesis and respiration. Zea mays seeds were germinated and cultured on nutrient solution with nickel concentrations of 50-200 μmol for a period of two weeks. Studied physiological makers included photosynthetic pigments content, the rate of Hill reaction, K+ efflux and carbohydrate leakage from the roots to the external solution and cell death as a Ni-induced membrane damage. By increasing Ni concentration up to 100 μmol, the content of chlorophyll a increased, but decreased at 200 μmol Ni. No significant changes in chlorophyll b and carotinoids content observed.The rate of Hill reaction as an ability of chlorophyll a in the reaction center of PSII680 to split water, decreased by increasing Ni concentration. Different concentrations of nickel increased the K+ efflux and sugar leakage from roots to the culture and the cell death of root tips. The present results suggested that the disruption of photosynthesis by Ni cannot be attributed to any single factor and appears to result from its combined effects on chloroplast structure, chlorophyll content and photosynthetic protein complexes and treatment with different levels of nickel may induce structural damage and alterations in membrane properties by generation of reactive oxygen species.

  4. Jasmonate ZIM-domain (JAZ protein regulates host and nonhost pathogen-induced cell death in tomato and Nicotiana benthamiana.

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    Yasuhiro Ishiga

    Full Text Available The nonhost-specific phytotoxin coronatine (COR produced by several pathovars of Pseudomonas syringae functions as a jasmonic acid-isoleucine (JA-Ile mimic and contributes to disease development by suppressing plant defense responses and inducing reactive oxygen species in chloroplast. It has been shown that the F-box protein CORONATINE INSENSITIVE 1 (COI1 is the receptor for COR and JA-Ile. JASMONATE ZIM DOMAIN (JAZ proteins act as negative regulators for JA signaling in Arabidopsis. However, the physiological significance of JAZ proteins in P. syringae disease development and nonhost pathogen-induced hypersensitive response (HR cell death is not completely understood. In this study, we identified JAZ genes from tomato, a host plant for P. syringae pv. tomato DC3000 (Pst DC3000, and examined their expression profiles in response to COR and pathogens. Most JAZ genes were induced by COR treatment or inoculation with COR-producing Pst DC3000, but not by the COR-defective mutant DB29. Tomato SlJAZ2, SlJAZ6 and SlJAZ7 interacted with SlCOI1 in a COR-dependent manner. Using virus-induced gene silencing (VIGS, we demonstrated that SlJAZ2, SlJAZ6 and SlJAZ7 have no effect on COR-induced chlorosis in tomato and Nicotiana benthamiana. However, SlJAZ2-, SlJAZ6- and SlJAZ7-silenced tomato plants showed enhanced disease-associated cell death to Pst DC3000. Furthermore, we found delayed HR cell death in response to the nonhost pathogen Pst T1 or a pathogen-associated molecular pattern (PAMP, INF1, in SlJAZ2- and SlJAZ6-silenced N. benthamiana. These results suggest that tomato JAZ proteins regulate the progression of cell death during host and nonhost interactions.

  5. Defense responses in two ecotypes of Lotus japonicus against non-pathogenic Pseudomonas syringae.

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    Cesar D Bordenave

    Full Text Available Lotus japonicus is a model legume broadly used to study many important processes as nitrogen fixing nodule formation and adaptation to salt stress. However, no studies on the defense responses occurring in this species against invading microorganisms have been carried out at the present. Understanding how this model plant protects itself against pathogens will certainly help to develop more tolerant cultivars in economically important Lotus species as well as in other legumes. In order to uncover the most important defense mechanisms activated upon bacterial attack, we explored in this work the main responses occurring in the phenotypically contrasting ecotypes MG-20 and Gifu B-129 of L. japonicus after inoculation with Pseudomonas syringae DC3000 pv. tomato. Our analysis demonstrated that this bacterial strain is unable to cause disease in these accessions, even though the defense mechanisms triggered in these ecotypes might differ. Thus, disease tolerance in MG-20 was characterized by bacterial multiplication, chlorosis and desiccation at the infiltrated tissues. In turn, Gifu B-129 plants did not show any symptom at all and were completely successful in restricting bacterial growth. We performed a microarray based analysis of these responses and determined the regulation of several genes that could play important roles in plant defense. Interestingly, we were also able to identify a set of defense genes with a relative high expression in Gifu B-129 plants under non-stress conditions, what could explain its higher tolerance. The participation of these genes in plant defense is discussed. Our results position the L. japonicus-P. syringae interaction as a interesting model to study defense mechanisms in legume species.

  6. The plastid-localized pfkB-type carbohydrate kinases FRUCTOKINASE-LIKE 1 and 2 are essential for growth and development of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Gilkerson Jonathan

    2012-07-01

    Full Text Available Abstract Background Transcription of plastid-encoded genes requires two different DNA-dependent RNA polymerases, a nuclear-encoded polymerase (NEP and plastid-encoded polymerase (PEP. Recent studies identified two related pfkB-type carbohydrate kinases, named FRUCTOKINASE-LIKE PROTEIN (FLN1 and FLN2, as components of the thylakoid bound PEP complex in both Arabidopsis thaliana and Sinapis alba (mustard. Additional work demonstrated that RNAi-mediated reduction in FLN expression specifically diminished transcription of PEP-dependent genes. Results Here, we report the characterization of Arabidopsis FLN knockout alleles to examine the contribution of each gene in plant growth, chloroplast development, and in mediating PEP-dependent transcription. We show that fln plants have severe phenotypes with fln1 resulting in an albino phenotype that is seedling lethal without a source of exogenous carbon. In contrast, fln2 plants display chlorosis prior to leaf expansion, but exhibit slow greening, remain autotrophic, can grow to maturity, and set viable seed. fln1 fln2 double mutant analysis reveals haplo-insufficiency, and fln1 fln2 plants have a similar, but more severe phenotype than either single mutant. Normal plastid development in both light and dark requires the FLNs, but surprisingly skotomorphogenesis is unaffected in fln seedlings. Seedlings genetically fln1-1 with dexamethasone-inducible FLN1-HA expression at germination are phenotypically indistinguishable from wild-type. Induction of FLN-HA after 24 hours of germination cannot rescue the mutant phenotype, indicating that the effects of loss of FLN are not always reversible. Examination of chloroplast gene expression in fln1-1 and fln2-1 by qRT-PCR reveals that transcripts of PEP-dependent genes were specifically reduced compared to NEP-dependent genes in both single mutants. Conclusions Our results demonstrate that each FLN protein contributes to wild type growth, and acting additively are

  7. Isolation of Xylella fastidiosa from Citrus sinensis (L) Osb. And Vitis vinifera and study of genetic diversity in Costa Rica

    International Nuclear Information System (INIS)

    Xylella fastidiosa is a plant pathogenic bacterium that causes diseases in different crops. Symptoms similar to those caused by citrus variegated chlorosis (CVC) were observed in sweet orange trees which served as shade and fences in coffee plantations in Costa Rica, in 2002. A total of 35 citrus trees and 24 vines from eight different districts and 3 respectively were evaluated by 'double antibody sandwich enzyme-linked immunosorbent assay' (DASELISA), resulting in 21 citrus and 19 positive vid. From four citrus trees and six of vines, were obtained six isolates and seven isolates respectively in solid medium, whose morphological and biochemical characteristics coincided with those reported in the literature as characteristic of X. fastidiosa. The identity of the isolates is confirmed by the chain polymerase reaction (PCR) using primers 272-1/272-2int and RST31/RST33. Three isolates from Grecia (Alajuela Province) amplified a band of 500pb using specific primers 272-2int/CVC-1 for strains of X. fastidiosa that cause CVC. The genetic variability of isolates from each other in comparison with isolates of coffee in Costa Rica, U.S. grapes and citrus in Brazil have been studied using techniques of random amplification polymorphism DNA (RAPD) and length polymorphisms of restriction fragments (RFLPs) of the products obtained with primers int/272-2int JB-1/JB-2 and 272-1. The results showed a clear separation between citrus isolates of Costa Rica; and, an association of three of them with the strains of citrus in Brasil. Also, an association between strains of coffee of Costa Rica with grape vines in the U.S. An association of molecular analysis confirmed the data variance. (author)

  8. Biological characterization of fusapyrone and deoxyfusapyrone, two bioactive secondary metabolites of Fusarium semitectum.

    Science.gov (United States)

    Altomare, C; Perrone, G; Zonno, M C; Evidente, A; Pengue, R; Fanti, F; Polonelli, L

    2000-08-01

    Fusapyrone (1) and deoxyfusapyrone (2), two alpha-pyrones originally isolated from rice cultures of Fusarium semitectum, were tested in several biological assays. Compounds 1 and 2 showed considerable antifungal activity against several plant pathogenic and/or mycotoxigenic filamentous fungi, although they were inactive toward yeasts isolated from plants and the Gram-positive bacterium Bacillus megaterium in disk diffusion assays. Compound 1 was consistently more active than 2. Among the tested fungi, Fusarium species were the least sensitive to the two pyrones, while Alternaria alternata, Ascochyta rabiei, Aspergillusflavus, Botrytis cinerea, Cladosporium cucumerinum, Phoma tracheiphila, and Penicillium verrucosum were the most sensitive. Compounds 1 and 2 also showed good inhibitory activity toward agents of human mycoses. Aspergilli were the most sensitive, while some species-specific variability was found among the Candida spp. In an Artemia salina larvae bioassay, 1 was not toxic at the highest concentration tested (500 microM), whereas the LC(50) of 2 was 37.1 microM (21.8 microg/mL). Neither 1 nor 2 was phytotoxic in a panel of assays that monitored plant-cell toxicity, as well as wilt-, chlorosis-, and necrosis-inducing activity. Moreover, 2 stimulated the root elongation of tomato seedlings at doses of 10 and 100 microM. In consideration of the biological activities evidenced in this study, 1 and 2 appear to be potential candidates for biotechnological applications, as well as good models for studies on mechanism(s) of action and structure-activity relationships. PMID:10978211

  9. I. Identification and characterization of dasheen mosaic virus in Chinese evergreen plants (Aglaonema commutatum) in California. II. New approaches for detecting plant viruses

    Energy Technology Data Exchange (ETDEWEB)

    Kositratana, W.

    1985-01-01

    Chinese evergreen plants (Aglaonema commutatum) with symptoms of mild stunting, chlorosis, leaf distortion and mosaic, were observed in Southern California. Flexuous rods (ca. 750 nm) were detected in leaf dip and partially purified preparations. Dasheen mosac virus (DMV) was identified as the causal agent on the basis of host range, morphology and reaction with DMV antiserum in immunodouble diffusion and immunosorbent electron microscopy (ISEM) tests. Tetragonia expansa was found to be a new host of this virus. Surveys indicate that DMV is not widespread in cultivars of A. commutatum in Southern California. The virus was purified from leaves of seedling Philodendron selloum by clarification with CCl/sub 4/, CHCl/sub 3/, and Triton X-100, precipitation with PEG-8000 and centrifugation in either Cs/sub 2/SO/sub 4/-sucrose cushion gradients or Cs/sub 2/SO/sub 4/ equilibrium density gradients. Purified virions formed a single UV-absorbing infectious band with densities of 1.31 and 1.245 g/ml in CsCl/sub 2/ and Cs/sub 2/SO/sub 4/ equilibrium density gradients, respectively, and a sedimentation coefficient of 154 S as determined by a linear-log sucrose density gradient centrifugation. Dasheen mosaic virus has a plus-sense ssRNA with the M.W. of 3.2 x 10/sup 6/ under denaturing conditions. Molecular hybridization analysis using /sup 3/H-complementary DNA specific to DMV-Ca RNA showed that DMV-Ca isolate was more closely related to DMV-Fiji isolate than to DMV-Fla isolate, and was very distantly related to ZYMV, TEV. PeMoC and PVY.

  10. GROWTH AND PROPAGATION OF LIMNOBIUM LAEVIGATUM (HYDROCHARITACEAE UNDER DIFFERENT NUTRIENT CONCENTRATIONS

    Directory of Open Access Journals (Sweden)

    HÉCTOR APONTE

    Full Text Available Limnobium laevigatum is a floating macrophyte widely distributed in neotropical countries. Due to its potential role in bioremediation it is important to know the best conditions in which it can be propagated. One of the most important factors is the concentration of nutrients in the water. Therefore, the objective of the present work was to determine the nutrient concentration for optimal growth of L. laevigatum under laboratory conditions quantifying the parameters of biomass, occupied area, root size, and leaf production. Experiments were performed in which these morphological parameters were monitored over a period of 21 days along five nutrient concentrations of the water (0X, 12.5X, 25X, 50X and 100X; proportional to nutrient concentration. The highest leaf production, wet weight, number of ramets and leaf area were obtained at the intermediate nutrient concentration treatments (12.5X and 25X, while treatments 0X and 12.5X had higher root growth than the rest. Chlorosis and percentage of dead leaves followed opposite trends, with the first one being higher in the 0X treatment and progressively diminishing as the nutrients increased, with the latter being lower in that first treatment and increasing with the nutrient concentration. Relative growth rate (RGR was the highest in plants under 12.5X conditions with a value of 0.1239. The role of nutrients in the different physiological responses of the studied plant is discussed and a comparison of the RGR with other floating plant species is presented.

  11. [Micrococcus sp.--the pathogen of leaf necrosis of horse-chestnuts (Aesculus L.) in Kiev].

    Science.gov (United States)

    Iakovleva, L M; Makhinia, L V; Shcherbina, T N; Ogorodnik, L E

    2013-01-01

    A group of phytopathogenic bacteria was isolated from patterns of drying horse-chestnuts (Aesculus L.), which grow in Kyiv. The properties of slowly growing, highly aggressive microorganisms have been described in the paper. They grow up on the 8-10th day after sowing. The investigated microorganisms form very small (0.5-1 mm in diameter) colonies on the potato agar. Bacteria are protuberant, shining, smooth with flat edges, they are pale yellow, yellow, or pink. The bacteria are Gram-positive, spherical, are disposed in smears singly, in pairs, as accumulations, or netting. They are aerobes, do not form spores, are not mobile. They are inert in respect of different sources of carbon. They reduce nitrates, do not dilute gelatin, do not hydrolyze starch, do not release hydrogen sulphide and indole. The bacteria are catalase-positive, oxidase-negative. They do not cause potato and carrot rot. They lose quickly their viability under the laboratory conditions. The saturated acids C 14:0; C 15:0; C16:0; C18:0 have been revealed in the composition of cellular fatty acids. Microorganisms are identified as Micrococcus sp. Under artificial inoculation this highly aggressive pathogen causes drying of the horse-chestnut buds and necrosis, which occupies 1/3-1/2 of the leaf plate. A wide zone of chlorosis, surrounding necrosis, may occupy the whole leaf surface. The infected leaves use to twist up from the top (apex) or along a midrib and to dry. PMID:23866588

  12. Emerging pests and diseases threaten Eucalyptus camaldulensis plantations in Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    Deidda A

    2016-06-01

    Full Text Available The rapid growth and environmental adaptability of Eucalyptus species has favored their global cultivation for pulpwood production. On the island of Sardinia, Italy, eucalypt plantations were established in the 20th century primarily in areas reclaimed from marshland, but the trees are now grown all over the island as ornamentals or windbreaks, and for timber, pulp and honey production. In recent years, an unusual decline and mortality of unknown etiology has been observed in Eucalyptus camaldulensis (river red gum plantations throughout the island. Given the ecological and economic importance of eucalypt ecosystems in Sardinia, a survey was carried out in 2013 to determine which insect pests and fungal pathogens are directly involved in these phenomena. Field surveys throughout the island revealed severe infestations with the red gum lerp psyllid (Glycaspis brimblecombei at all 12 surveyed sites, with the greatest numbers of pre-imaginal stages and adults occurring between May and July. The adult population reached its peak in July, followed 2 months later by the peak population of its specific parasitoid, Psyllaephagus bliteus. Symptoms of leaf chlorosis, crown thinning, shoot and branch dieback, sunken cankers, epicormic shoots and exudations of kino gum were also observed at the 12 field sites. Symptomatic woody samples yielded fungal isolates representing three distinct families: Botryosphaeriaceae, Diaporthaceae and Valsaceae. Morphological and DNA sequence data revealed seven distinct fungal species, namely Diaporthe foeniculina, Neofusicoccum australe, N. luteum, N. mediterraneum, N. parvum, N. vitifusiforme and Valsa fabianae. Two putative new species of Cytospora were also identified. Neofusicoccum australe was the only species recovered from all 12 sites, with isolation frequencies of 51-95%. Pathogenicity trials revealed that all Neofusicoccum species except N. vitifusiforme are directly involved in the etiology of the observed

  13. Use of AIRS, OMI, MLS, and TES Data in Assessing Forest Ecosystem Exposure to Ozone

    Science.gov (United States)

    Spruce, Joseph P.

    2007-01-01

    Ground-level ozone at high levels poses health threats to exposed flora and fauna, including negative impacts to human health. While concern is common regarding depletion of ozone in the stratosphere, portions of the urban and rural United States periodically have high ambient levels of tropospheric ozone on the ground. Ozone pollution can cause a variety of impacts to susceptible vegetation (e.g., Ponderosa and Jeffrey pine species in the southwestern United States), such as stunted growth, alteration of growth form, needle or leaf chlorosis, and impaired ability to withstand drought-induced water stress. In addition, Southern Californian forests with high ozone exposures have been recently subject to multiyear droughts that have led to extensive forest overstory mortality from insect outbreaks and increased incidence of wildfires. Residual forests in these impacted areas may be more vulnerable to high ozone exposures and to other forest threats than ever before. NASA sensors collect a wealth of atmospheric data that have been used recently for mapping and monitoring regional tropospheric ozone levels. AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), MLS (Microwave Limb Sounder), and TES (Tropospheric Emission Spectrometer) data could be used to assess forest ecosystem exposure to ozone. Such NASA data hold promise for providing better or at least complementary synoptic information on ground-level ozone levels that Federal agency partners can use to assess forest health trends and to mitigate the threats as needed in compliance with Federal laws and mandates. NASA data products on ozone concentrations may be able to aid applications of DSTs (decision support tools) adopted by the USDA FS (U.S. Department of Agriculture Forest Service) and by the NPS (National Park Service), such as the Ozone Calculator, in which ground ozone estimates are employed to assess ozone impacts to forested vegetation.

  14. Phytophthora niederhauserii sp. nov., a polyphagous species associated with ornamentals, fruit trees and native plants in 13 countries.

    Science.gov (United States)

    Abad, Z Gloria; Abad, Jorge A; Cacciola, Santa Olga; Pane, Antonella; Faedda, Roberto; Moralejo, Eduardo; Pérez-Sierra, Ana; Abad-Campos, Paloma; Alvarez-Bernaola, Luis A; Bakonyi, József; Józsa, András; Herrero, Maria Luz; Burgess, Treena I; Cunnington, James H; Smith, Ian W; Balci, Yilmaz; Blomquist, Cheryl; Henricot, Béatrice; Denton, Geoffrey; Spies, Chris; Mcleod, Adele; Belbahri, Lassaad; Cooke, David; Kageyama, Koji; Uematsu, Seiji; Kurbetli, Ilker; Değirmenci, Kemal

    2014-01-01

    A non-papillate, heterothallic Phytophthora species first isolated in 2001 and subsequently from symptomatic roots, crowns and stems of 33 plant species in 25 unrelated botanical families from 13 countries is formally described here as a new species. Symptoms on various hosts included crown and stem rot, chlorosis, wilting, leaf blight, cankers and gumming. This species was isolated from Australia, Hungary, Israel, Italy, Japan, the Netherlands, Norway, South Africa, Spain, Taiwan, Turkey, the United Kingdom and United States in association with shrubs and herbaceous ornamentals grown mainly in greenhouses. The most prevalent hosts are English ivy (Hedera helix) and Cistus (Cistus salvifolius). The association of the species with acorn banksia (Banksia prionotes) plants in natural ecosystems in Australia, in affected vineyards (Vitis vinifera) in South Africa and almond (Prunus dulcis) trees in Spain and Turkey in addition to infection of shrubs and herbaceous ornamentals in a broad range of unrelated families are a sign of a wide ecological adaptation of the species and its potential threat to agricultural and natural ecosystems. The morphology of the persistent non-papillate ellipsoid sporangia, unique toruloid lobate hyphal swellings and amphigynous antheridia does not match any of the described species. Phylogenetic analysis based on sequences of the ITS rDNA, EF-1α, and β-tub supported that this organism is a hitherto unknown species. It is closely related to species in ITS clade 7b with the most closely related species being P. sojae. The name Phytophthora niederhauserii has been used in previous studies without the formal description of the holotype. This name is validated in this manuscript with the formal description of Phytophthora niederhauserii Z.G. Abad et J.A. Abad, sp. nov. The name is coined to honor Dr John S. Niederhauser, a notable plant pathologist and the 1990 World Food Prize laureate. PMID:24871599

  15. Transcript dynamics at early stages of molecular interactions of MYMIV with resistant and susceptible genotypes of the leguminous host, Vigna mungo.

    Science.gov (United States)

    Kundu, Anirban; Patel, Anju; Paul, Sujay; Pal, Amita

    2015-01-01

    Initial phases of the MYMIV-Vigna mungo interaction is crucial in determining the infection phenotype upon challenging with the virus. During incompatible interaction, the plant deploys multiple stratagems that include extensive transcriptional alterations defying the virulence factors of the pathogen. Such molecular events are not frequently addressed by genomic tools. In order to obtain a critical insight to unravel how V. mungo respond to Mungbean yellow mosaic India virus (MYMIV), we have employed the PCR based suppression subtractive hybridization technique to identify genes that exhibit altered expressions. Dynamics of 345 candidate genes are illustrated that differentially expressed either in compatible or incompatible reactions and their possible biological and cellular functions are predicted. The MYMIV-induced physiological aspects of the resistant host include reactive oxygen species generation, induction of Ca2+ mediated signaling, enhanced expression of transcripts involved in phenylpropanoid and ubiquitin-proteasomal pathways; all these together confer resistance against the invader. Elicitation of genes implicated in salicylic acid (SA) pathway suggests that immune response is under the regulation of SA signaling. A significant fraction of modulated transcripts are of unknown function indicating participation of novel candidate genes in restricting this viral pathogen. Susceptibility on the other hand, as exhibited by V. mungo Cv. T9 is perhaps due to the poor execution of these transcript modulation exhibiting remarkable repression of photosynthesis related genes resulting in chlorosis of leaves followed by penalty in crop yield. Thus, the present findings revealed an insight on the molecular warfare during host-virus interaction suggesting plausible signaling mechanisms and key biochemical pathways overriding MYMIV invasion in resistant genotype of V. mungo. In addition to inflate the existing knowledge base, the genomic resources identified in

  16. Transcript dynamics at early stages of molecular interactions of MYMIV with resistant and susceptible genotypes of the leguminous host, Vigna mungo.

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    Anirban Kundu

    Full Text Available Initial phases of the MYMIV-Vigna mungo interaction is crucial in determining the infection phenotype upon challenging with the virus. During incompatible interaction, the plant deploys multiple stratagems that include extensive transcriptional alterations defying the virulence factors of the pathogen. Such molecular events are not frequently addressed by genomic tools. In order to obtain a critical insight to unravel how V. mungo respond to Mungbean yellow mosaic India virus (MYMIV, we have employed the PCR based suppression subtractive hybridization technique to identify genes that exhibit altered expressions. Dynamics of 345 candidate genes are illustrated that differentially expressed either in compatible or incompatible reactions and their possible biological and cellular functions are predicted. The MYMIV-induced physiological aspects of the resistant host include reactive oxygen species generation, induction of Ca2+ mediated signaling, enhanced expression of transcripts involved in phenylpropanoid and ubiquitin-proteasomal pathways; all these together confer resistance against the invader. Elicitation of genes implicated in salicylic acid (SA pathway suggests that immune response is under the regulation of SA signaling. A significant fraction of modulated transcripts are of unknown function indicating participation of novel candidate genes in restricting this viral pathogen. Susceptibility on the other hand, as exhibited by V. mungo Cv. T9 is perhaps due to the poor execution of these transcript modulation exhibiting remarkable repression of photosynthesis related genes resulting in chlorosis of leaves followed by penalty in crop yield. Thus, the present findings revealed an insight on the molecular warfare during host-virus interaction suggesting plausible signaling mechanisms and key biochemical pathways overriding MYMIV invasion in resistant genotype of V. mungo. In addition to inflate the existing knowledge base, the genomic resources

  17. Biochemical responses of filamentous algae in different aquatic ecosystems in South East Turkey and associated water quality parameters.

    Science.gov (United States)

    Çelekli, Abuzer; Arslanargun, Hamdullah; Soysal, Çiğdem; Gültekin, Emine; Bozkurt, Hüseyin

    2016-11-01

    To the best of our knowledge, any study about biochemical response of filamentous algae in the complex freshwater ecosystems has not been found in the literature. This study was designed to explore biochemical response of filamentous algae in different water bodies from May 2013 to October 2014, using multivariate approach in the South East of Turkey. Environmental variables were measured in situ: water temperature, oxygen concentration, saturation, conductivity, salinity, pH, redox potential, and total dissolved solid. Chemical variables of aqueous samples and biochemical compounds of filamentous algae were also measured. It was found that geographic position and anthropogenic activities had strong effect on physico-chemical variables of water bodies. Variation in environmental conditions caused change in algal biomass composition due to the different response of filamentous species, also indicated by FTIR analysis. Biochemical responses not only changed from species to species, but also varied for the same species at different sampling time and sampling stations. Multivariate analyses showed that heavy metals, nutrients, and water hardness were found as the important variables governing the temporal and spatial succession and biochemical compounds. Nutrients, especially nitrate, could stimulate pigment and total protein production, whereas high metal content had adverse effects. Amount of malondialdehyde (MDA), H2O2, total thiol groups, total phenolic compounds, proline, total carbohydrate, and metal bioaccumulation by filamentous algae could be closely related with heavy metals in the ecosystems. Significant increase in MDA, H2O2, total thiol group, total phenolic compounds, and proline productions by filamentous algae and chlorosis phenomenon seemed to be an important strategy for alleviating environmental factors-induced oxidative stress as biomarkers. PMID:27508982

  18. Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 confers enhanced salinity tolerance in chimeric sugar beet (Beta vulgaris L.

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    Guo-Qiang eWu

    2015-07-01

    Full Text Available Salinity is one of the major abiotic stresses that limit the growth and productivity of sugar beet (Beta vulgaris L.. To improve sugar beet’s salinity tolerance, the ZxNHX and ZxVP1-1 genes encoding tonoplast Na+/H+ antiporter and H+-PPase from xerophyte Zygophyllum xanthoxylum were co-expressed by Agrobacterium tumefaciens-mediated transformation. It is showed here that co-expression of ZxNHX and ZxVP1-1 confers enhanced salinity tolerance to the transformed sugar beet plants compared with the wild-type (WT plants. The chimeric plants grew well in the presence of high salinity (400 mM NaCl, whereas WT plants displayed chlorosis and died within 8 days. Compared to WT plants, the chimeric plants co-expressing ZxNHX and ZxVP1-1 accumulated more proline, Na+ and K+ in their leaves and petioles when exposed to high salinity, which caused lower solute potential, retained more water and thus subjected to lesser cell membrane damage. Interestingly, the chimeric plants accumulated higher sucrose, glucose and fructose contents in their storage roots than WT plants in the absence or presence of high salinity. Our results suggested that co-expression of ZxNHX and ZxVP1-1 improved the osmoregulatory capacity in chimeric sugar beet through increased compartmentalization of ions into the vacuoles by enhancing the activity of proton pumps and thus mitigated Na+-toxicity for plants.

  19. Biology and harmfulness of Planococcus vovae (Nassonov (Hemiptera: Pseudococcidae in Belgrade area

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    Draga Graora

    2014-03-01

    Full Text Available Planococcus vovae (Nassonov (Hemiptera: Pseudococcidae is an important pest on plants of the family Cupressaceae. Its numerous populations have been present in recent years on Juniperus spp. in Belgrade. Feeding by sap-sucking on all aboveground plant organs, it causes growth stagnation, chlorosis, drying of needles and branches, and even of entire plants under heavy infestation. Additionally, the scale excretes large quantities of honeydew, on which sooty mold develops, reducing photosynthesis and causing faster plant deterioration. Throughout 2007 and 2008, P. vovae was recorded on Juniperus spp. in 12 localities in Belgrade, and on Thuja sp. in a single locality. The pest was found to develop three generations per year and overwinter on branches at the egg or second instar stages. The first generation adults were observed at the end of May, the second generation at the beginning of August, while the third generation was recorded at the beginning of October. Different overwintering modes, and variable oviposition, embryonic and larval development periods led to an overlapping of generations and continuous presence of all developmental stages on plants. In different localities the infestation of plants varied in abundance from a few individual specimens to very large colonies. The highest infestation intensity was recorded in the localities Bežanija, Dorćol and Voždovac. The predatory species Chrysoperla carnea (Stephens (Neuroptera: Chrysopidae and Nephus bipunctatus (Kugelann (Coleoptera: Coccinelidae were found in the scale colonies. Regarding N. bipunctatus, this was its first record as a new species in the Serbian fauna.

  20. Characterization of the LysR-type transcriptional regulator YcjZ-like from Xylella fastidiosa overexpressed in Escherichia coli.

    Science.gov (United States)

    Santiago, André S; Santos, Clelton A; Mendes, Juliano S; Toledo, Marcelo A S; Beloti, Lilian L; Souza, Alessandra A; Souza, Anete P

    2015-09-01

    The Xylella fastidiosa 9a5c strain is a xylem-limited phytopathogen that is the causal agent of citrus variegated chlorosis (CVC). This bacterium is able to form a biofilm and occlude the xylem vessels of susceptible plants, which leads to significant agricultural and economic losses. Biofilms are associated with bacterial pathogenicity because they are very resistant to antibiotics and other metal-based chemicals that are used in agriculture. The X. fastidiosa YcjZ-like (XfYcjZ-like) protein belongs to the LysR-type transcriptional regulator (LTTR) family and is involved in various cellular functions that range from quorum sensing to bacterial survival. In the present study, we report the cloning, expression and purification of XfYcjZ-like, which was overexpressed in Escherichia coli. The secondary folding of the recombinant and purified protein was assessed by circular dichroism, which revealed that XfYcjZ-like contains a typical α/β fold. An initial hydrodynamic characterization showed that XfYcjZ-like is a globular tetramer in solution. In addition, using a polyclonal antibody against XfYcjZ-like, we assessed the expression profile of this protein during the different developmental phases of X. fastidiosa in in vitro cultivated biofilm cells and demonstrated that XfYcjZ-like is upregulated in planktonic cells in response to a copper shock treatment. Finally, the ability of XfYcjZ-like to interact with its own predicted promoter was confirmed in vitro, which is a typical feature of LysR. Taken together, our findings indicated that the XfYcjZ-like protein is involved in both the organization of the architecture and the maturation of the bacterial biofilm and that it is responsive to oxidative stress. PMID:25979465

  1. Directed evolution induces tributyrin hydrolysis in a virulence factor of Xylella fastidiosa using a duplicated gene as a template.

    Science.gov (United States)

    Gouran, Hossein; Chakraborty, Sandeep; Rao, Basuthkar J; Asgeirsson, Bjarni; Dandekar, Abhaya

    2014-01-01

    Duplication of genes is one of the preferred ways for natural selection to add advantageous functionality to the genome without having to reinvent the wheel with respect to catalytic efficiency and protein stability. The duplicated secretory virulence factors of Xylella fastidiosa (LesA, LesB and LesC), implicated in Pierce's disease of grape and citrus variegated chlorosis of citrus species, epitomizes the positive selection pressures exerted on advantageous genes in such pathogens. A deeper insight into the evolution of these lipases/esterases is essential to develop resistance mechanisms in transgenic plants. Directed evolution, an attempt to accelerate the evolutionary steps in the laboratory, is inherently simple when targeted for loss of function. A bigger challenge is to specify mutations that endow a new function, such as a lost functionality in a duplicated gene. Previously, we have proposed a method for enumerating candidates for mutations intended to transfer the functionality of one protein into another related protein based on the spatial and electrostatic properties of the active site residues (DECAAF). In the current work, we present in vivo validation of DECAAF by inducing tributyrin hydrolysis in LesB based on the active site similarity to LesA. The structures of these proteins have been modeled using RaptorX based on the closely related LipA protein from Xanthomonas oryzae. These mutations replicate the spatial and electrostatic conformation of LesA in the modeled structure of the mutant LesB as well, providing in silico validation before proceeding to the laborious in vivo work. Such focused mutations allows one to dissect the relevance of the duplicated genes in finer detail as compared to gene knockouts, since they do not interfere with other moonlighting functions, protein expression levels or protein-protein interaction. PMID:25717364

  2. Sequence/structural analysis of xylem proteome emphasizes pathogenesis-related proteins, chitinases and β-1, 3-glucanases as key players in grapevine defense against Xylella fastidiosa.

    Science.gov (United States)

    Chakraborty, Sandeep; Nascimento, Rafael; Zaini, Paulo A; Gouran, Hossein; Rao, Basuthkar J; Goulart, Luiz R; Dandekar, Abhaya M

    2016-01-01

    Background. Xylella fastidiosa, the causative agent of various plant diseases including Pierce's disease in the US, and Citrus Variegated Chlorosis in Brazil, remains a continual source of concern and economic losses, especially since almost all commercial varieties are sensitive to this Gammaproteobacteria. Differential expression of proteins in infected tissue is an established methodology to identify key elements involved in plant defense pathways. Methods. In the current work, we developed a methodology named CHURNER that emphasizes relevant protein functions from proteomic data, based on identification of proteins with similar structures that do not necessarily have sequence homology. Such clustering emphasizes protein functions which have multiple copies that are up/down-regulated, and highlights similar proteins which are differentially regulated. As a working example we present proteomic data enumerating differentially expressed proteins in xylem sap from grapevines that were infected with X. fastidiosa. Results. Analysis of this data by CHURNER highlighted pathogenesis related PR-1 proteins, reinforcing this as the foremost protein function in xylem sap involved in the grapevine defense response to X. fastidiosa. β-1, 3-glucanase, which has both anti-microbial and anti-fungal activities, is also up-regulated. Simultaneously, chitinases are found to be both up and down-regulated by CHURNER, and thus the net gain of this protein function loses its significance in the defense response. Discussion. We demonstrate how structural data can be incorporated in the pipeline of proteomic data analysis prior to making inferences on the importance of individual proteins to plant defense mechanisms. We expect CHURNER to be applicable to any proteomic data set. PMID:27257535

  3. Quantification and localization of hesperidin and rutin in Citrus sinensis grafted on C. limonia after Xylella fastidiosa infection by HPLC-UV and MALDI imaging mass spectrometry.

    Science.gov (United States)

    Soares, Márcio Santos; da Silva, Danielle Fernandes; Forim, Moacir Rossi; da Silva, Maria Fátima das Graças Fernandes; Fernandes, João Batista; Vieira, Paulo Cezar; Silva, Denise Brentan; Lopes, Norberto Peporine; de Carvalho, Sérgio Alves; de Souza, Alessandra Alves; Machado, Marcos Antônio

    2015-07-01

    A high performance liquid chromatography-ultraviolet (HPLC-UV) method was developed for quantifying hesperidin and rutin levels in leaves and stems of Citrus limonia, with a good linearity over a range of 1.0-80.0 and 1.0-50.0 μg mL(-1) respectively, with r(2)>0.999 for all curves. The limits of detection (LOD) for both flavonoids were 0.6 and 0.5 μg mL(-1), respectively, with quantification (LOQ) being 2.0 and 1.0 μg mL(-1), respectively. The quantification method was applied to Citrus sinensis grafted onto C. limonia with and without CVC (citrus variegated chlorosis) symptoms after Xylella fastidiosa infection. The total content of rutin was low and practically constant in all analyses in comparison with hesperidin, which showed a significant increase in its amount in symptomatic leaves. Scanning electron microscopy studies on leaves with CVC symptoms showed vessel occlusion by biofilm, and a crystallized material was noted. Considering the difficulty in isolating these crystals for analysis, tissue sections were analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to confirm the presence of hesperidin at the site of infection. The images constructed from MS/MS data with a specific diagnostic fragment ion (m/z 483) also showed higher ion intensities for it in infected plants than in healthy ones, mainly in the vessel regions. These data suggest that hesperidin plays a role in the plant-pathogen interaction, probably as a phytoanticipin. This method was also applied to C. sinensis and C. limonia seedlings, and comparison with the graft results showed that the rootstock had an increased hesperidin content ∼3.6 fold greater in the graft stem than in the stem of C. sinensis seedlings. Increase in hesperidin content by rootstock can be related to induced internal defense mechanisms. PMID:25749617

  4. Characterization of Rhynchosia yellow mosaic Yucatan virus, a new recombinant begomovirus associated with two fabaceous weeds in Yucatan, Mexico.

    Science.gov (United States)

    Hernández-Zepeda, C; Brown, J K; Moreno-Valenzuela, O A; Argüello-Astorga, G; Idris, A M; Carnevali, G; Rivera-Bustamante, R F

    2010-10-01

    Rhynchosia minima (L.) DC. (Fabaceae) plants exhibiting bright golden mosaic symptoms were previously associated with begomovirus infection in Yucatan, México [1]. To characterize the begomovirus infecting these plants, the complete bipartite genome was cloned and sequenced. Sequence comparisons indicated that the virus was distinct from all other begomoviruses known to date, including those previously identified from symptomatic R. minima, and the name Rhynchosia yellow mosaic Yucatan virus (RhYMYuV) is proposed. Pairwise comparisons indicated that RhYMYuV DNA-A [2,597 nt, (EU021216)] and DNA-B [2,542 nt, (FJ792608)] components shared the highest nt sequence identity with Cabbage leaf curl virus (CaLCuV), 87% for component A and 71% for component B. Phylogenetic analysis indicated that both components of RhYMYuV are most closely related to other New World begomoviruses, having as closest relatives immediate outliers to the major Squash leaf curl virus (SLCV) clade. Recombination analysis of the RhYMYuV genome indicated that the DNA-A component has arisen through intermolecular recombination. R. minima plants inoculated with the monomeric clones developed a bright yellow mosaic similar to symptoms observed in naturally infected plants, confirming that the clones were infectious. Nicotiana benthamiana plants biolistically inoculated with monomeric clones developed curling and chlorosis in the newly emerging leaves. RhYMYuV was also detected in symptomatic Desmodium sect. Scorpiurus Benth. (Fabaceae) that were collected near the RhYMYuV-infected plants. PMID:20574644

  5. First genome analysis and molecular characterization of Chickpea chlorotic dwarf virus Egyptian isolate infecting squash.

    Science.gov (United States)

    Fahmy, Inas Farouk; Taha, Omnia; El-Ashry, Abdel Nasser

    2015-06-01

    This study aims to identifying and characterizing some molecular properties of geminiviruses co-infection in squash field crop cultivated in Egypt. Squash crops observed to be heavily infected with several insect vectors, also severe chlorosis and stunting was observed. Electron microscopic analysis has revealed geminate capsid particles which indicate the infection of Geminiviruses, especially SqLCV which represent an economic problem to squash filed crop in Egypt. We have investigated possible mixed infections with different plant viruses associated with chlorotic stunt diseases and or other genus groups of geminiviruses. The main objective of this study is to investigate the recombination events, possible recombinants and variants among these genera in the same family differing in vector transmission. This is the first report of the molecular characterization, phylogenetic analysis and putative recombination events of the full length genome of the Chickpea Chlorotic Dwarf Mastrevirus in Egypt. And the first report of co-infection with another begomovirus infecting squash plants. A full length clone of both viruses were isolated and characterized at the molecular level. The complete nucleotide sequence of DNA-A was determined (2,572 bp) and submitted to the genbank under accession no. KF692356. The isolate from Egypt has about 97.8 % homology with the Chickpea chlorotic dwarf virus (CpCDV) isolate from Syria DNA-A isolate FR687959, a 83.2 % homology with the Sudan isolate AM933134 and a 82.7 % homology with Pakistan isolate FR687960. To best of our knowledge this is the first report of complete genome of CpCDV that infect squash plants in Egypt and worldwide.

  6. Molecular, physiological and morphological analysis of waterlogging tolerance in clonal genotypes of Theobroma cacao L.

    Science.gov (United States)

    Bertolde, Fabiana Zanelato; De Almeida, Alex-Alan Furtado; Corrêa, Ronan Xavier; Gomes, Fábio Pinto; Gaiotto, Fernanda Amato; Baligar, Virupax C; Loguercio, Leandro Lopes

    2010-01-01

    In soil, anoxia conditions generated by waterlogging induce changes in genetic, morphological and physiological processes, altering the growth and development of plants. Mass propagation of cacao (Theobroma cacao L.) plantlets (clones) is affected by waterlogging caused by heavy rains and irrigation methods used to induce rooting. An experiment was undertaken to assess the effects of a 45-day flooding (anoxia) on physiological and morphological traits of 35 elite cacao genotypes, aiming at potentially identifying those with greater tolerance to flooding of the growth substrate. Eighteen fluorochrome-labeled microsatellite (SSR) primer pairs were used to assess genetic variability among clones, with 248 alleles being amplified and used to calculate similarity coefficients. The resulting dendrogram indicated the presence of four major groups, in which two represented 60% and 31% of the genotypes tested. A general trend toward high levels of heterozygosity was also found for physiological and morphological traits. The survival index (IS) for flood tolerance observed varied from 30 to 96%. Clones TSA-654, TSA-656, TSA-792, CA-1.4, CEPEC-2009 and PH-17 showed an IS value above 94%, whereas CEPEC-2010, CEPEC-2002, CA-7.1 and VB-903 clones were those mostly affected by waterlogging, with IS value below 56%. All genotypes displayed lenticel and adventitious root formation in response to waterlogging, although with different intensities. To determine whether patterns of physiological response could be associated with tolerance to anoxia, a similarity-grouping analysis was performed using the ratio between waterlogged and control values obtained for a series of physiological variables assessed. No specific pattern of physiological and morphological responses to waterlogging was strictly associated with survival of plantlets. However, results revealed by the dendrogram suggest that absence of leaf chlorosis may be a proper trait to indicate cacao clones with higher survival

  7. NEW VARIETIES AND FORMATIONS OF GRAPES ROOTSTOCKS

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    Zhukov A. I.

    2015-10-01

    Full Text Available In the modern wine growing, for fighting against root phylloxera an inoculation of European-Asian grapes varieties on rootstocks steady against this wrecker is used. In this article we present the information about the types of rootstocks of domestic and foreign breeding used in the modern branch of wine growing. The area of their use is described; the useful properties of rootstocks and their demerits are highlighted. The purpose of this work is creating new grapes rootstocks which wouldn't have the merits of existing rootstocks. The short description of the grapes rootstocks which were created in the Anapa Zonal Experimental Station of wine growing and winemaking such as AZOS-1, AZOS-2, AZOS-3, AZOS-4, AZOS-5 and AZOS-6 is given in the article. It is indicated that these rootstocks have a high resistance to a leaf form of phylloxera, to chlorosis and to some other diseases of a grapes bush. They have the short period of vegetation, high quantity of standard cutting from hectare and other useful properties. In the article the description of a new formation of rootstocks grapes bushes of "AOS- 1" and "AOS-2" with a free trail shoots is given. This construction of grapes bush is developed by the Anapa's Zonal Experimental Station of wine growing and winemaking. We have also given all the advantages of this forming in comparison with other designs of grapes bushes. It is especially noted that use of this forming of bushes increases the productivity per men in the process of bushes scrap and preparation of cutting; the expenditures on the struggle against diseases and wreckers on the vineyards are reduced; the quantity standard of grapes cutting increases by 27-33%

  8. Starch accumulation during hydroponic growth of spinach and basil plants under carbon dioxide enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Holbrook, G.P.; Hansen, J.; Wallick, K.; Zinnen, T.M. (North Illinois University, de Kalb, IL (USA). Dept. of Biological Sciences)

    1993-04-01

    The effects of CO[sub 2] enrichment, photoperiod duration, and inorganic phosphate levels on growth and starch accumulaton by spinach and basil plants were studied in a commercial hydroponic facility. During a 3-week growth period, both species exhibited increased whole-plant fresh weight as a result of an increase in atmospheric CO[sub 2] concentration from 400 to 1500 mul/1. However, basil leaves exhibited a 1.5- to 2-fold greater increase in specific leaf weight (SLW), and accumulated starch to much greater levels than did leaves of spinach. At 1500 mul CO[sub 2]/1, starch accounted for up to 38% of SLW with basil compared to [lt] 10% of SLW with spinach. The maximum ratio of starch/chlorophyll was 55.0 in basil leaves vs 8.0 in spinach leaves. High ratio values were associated with the appearance of chlorotic symptoms in leaves of basil grown under CO[sub 2] enrichment, whereas spinach did not exhibit chlorosis. Increasing inorganic phosphate concentrations from 0.7 to 1.8 mM in the hydroponic medium did not appreciably affect leaf starch accumulation in either species. Starch accumulation in basil leaves was not consistently related to the duration of the photoperiod. However, photoperiod-induced changes in leaf starch levels were much greater in basil than spinach. The results clearly indicate that different horticultural crops can show diverse responses to CO[sub 2] enrichment, and thus highlight the need to develop individual growth strategies to optimize production quality of each species.

  9. Continuous light increases growth, daily carbon gain, antioxidants, and alters carbohydrate metabolism in a cultivated and a wild tomato species.

    Science.gov (United States)

    Haque, Mohammad S; Kjaer, Katrine H; Rosenqvist, Eva; Ottosen, Carl-Otto

    2015-01-01

    Cultivated tomato species develop leaf injury while grown in continuous light (CL). Growth, photosynthesis, carbohydrate metabolism and antioxidative enzyme activities of a cultivated (Solanum lycopersicum L. 'Aromata') and a wild tomato species (Solanum pimpinellifolium L.) were compared in this study aiming to analyze the species-specific differences and thermoperiod effects in responses to CL. The species were subjected to three photoperiodic treatments for 12 days in climate chambers: 16-h photoperiod with a light/dark temperature of 26/16°C (P16D10 or control); CL with a constant temperature of 23°C (P24D0); CL with a variable temperature of 26/16°C (P24D10). The results showed that both species grown in CL had higher dry matter production due to the continuous photosynthesis and a subsequent increase in carbon gain. In S. lycopersicum, the rate of photosynthesis and the maximum photochemical efficiency of photosystem II declined in CL with the development of leaf chlorosis, reduction in the leaf chlorophyll content and a higher activity of antioxidative enzymes. The normal diurnal patterns of starch and sugar were only present under control conditions. The results demonstrated that CL conditions mainly affected the photosynthetic apparatus of a cultivated species (S. lycopersicum), and to a less degree to the wild species (S. pimpinellifolium). The negative effects of the CL could be alleviated by diurnal temperature variations, but the physiological mechanisms behind these are less clear. The results also show that the genetic potential for reducing the negative effects of CL does exist in the tomato germplasm. PMID:26217371

  10. Continuous light increases growth, daily carbon gain, antioxidants and alters carbohydrate metabolism in a cultivated and a wild tomato species

    Directory of Open Access Journals (Sweden)

    Mohammad Sabibul Haque

    2015-07-01

    Full Text Available Cultivated tomato species develop leaf injury while grown in continuous light (CL. Growth, photosynthesis, carbohydrate metabolism and antioxidative enzyme activities of a cultivated (Solanum lycopersicum L. ‘Aromata’ and a wild tomato species (Solanum pimpinellifolium L. were compared in this study aiming to analyse the species-specific differences and thermoperiod effects in responses to CL. The species were subjected to three photoperiodic treatments for 12 days in climate chambers: 16-h photoperiod with a light/dark temperature of 26/16ºC (P16D10 or control; CL with a constant temperature of 23ºC (P24D0; CL with a variable temperature of 26/16ºC (P24D10. The results showed that both species grown in CL had higher dry matter production due to the continuous photosynthesis and a subsequent increase in carbon gain. In S. lycopersicum, the rate of photosynthesis and the maximum photochemical efficiency of photosystem II declined in CL with the development of leaf chlorosis, reduction in the leaf chlorophyll content and a higher activity of antioxidative enzymes. The normal diurnal patterns of starch and sugar were only present under control conditions. The results demonstrated that CL conditions mainly affected the photosynthetic apparatus of a cultivated species (S. lycopersicum, and to a less degree to the wild species (S. pimpinellifolium. The negative effects of the CL could be alleviated by diurnal temperature variations, but the physiological mechanisms behind these are less clear. The results also show that the genetic potential for reducing the negative effects of CL does exist in the tomato germplasm.

  11. Possibilities of chemical weed control in Lupinus albus and Lupinus luteus-screening of herbicides.

    Science.gov (United States)

    Dewitte, K; Latré, J; Haesaert, G

    2006-01-01

    Weed control in sweet lupins is still a problem. Especially the phytotoxicity of herbicides in sweet lupins is not enough studied. Therefore a screening with 16 selected herbicides and 4 lupin varieties has been set up. During the growing season 2005, 10 of the tested herbicides were applied in pre-emergence, 6 in post-emergence. Pre-emergence: Most of the active matters tested in pre-emergence were not phytotoxic for lupins. Pendimethalin (1000 g/ha), linuron (500 g/ha), chlorotoluron (1500 g/ha), prosulfocarb (2400 g/ha), clomazone (72 g/ha), isoxaben (100 g/ha), metamitron (1050 g/ha) and dimethenamid-P (720 g/ha) were applied without causing any significant phytotoxic symptoms. Only the lupins treated with aclonifen (1200 g/ha) showed a significant growth inhibition, 3 weeks after treatment. Significantly more chlorosis was noticed when the lupins were treated with aclonifen or with diflufenican, in preemergence. Post-emergence: In post-emergence, diflufenican (50 g/ha) did not cause any crop damage. Florasulam (5 g/ha) caused almost 100% necrosis in L. albus as well as in L. luteus. Bentazon (652 g/ha), thifensulfuron-methyl (15 g/ha) and metribuzin (175 g/ha) caused obvious necrosis and growth inhibition of the crop. The growth inhibition was significantly more severe for lupins treated with bentazon than if they were treated with thifensulfuron-methyl or metribuzin. Three weeks after treatment, clomazone (90 g/ha) and diflufenican (50 g/ha), did not cause any crop injury at all. The results indicated an interesting range of active matters which can be applied in pre-emergence, but weed control in post-emergence stays difficult.

  12. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    Directory of Open Access Journals (Sweden)

    Lígia S Muranaka

    Full Text Available Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC. The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC, a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS. The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer. HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria.

  13. Phytophthora niederhauserii sp. nov., a polyphagous species associated with ornamentals, fruit trees and native plants in 13 countries.

    Science.gov (United States)

    Abad, Z Gloria; Abad, Jorge A; Cacciola, Santa Olga; Pane, Antonella; Faedda, Roberto; Moralejo, Eduardo; Pérez-Sierra, Ana; Abad-Campos, Paloma; Alvarez-Bernaola, Luis A; Bakonyi, József; Józsa, András; Herrero, Maria Luz; Burgess, Treena I; Cunnington, James H; Smith, Ian W; Balci, Yilmaz; Blomquist, Cheryl; Henricot, Béatrice; Denton, Geoffrey; Spies, Chris; Mcleod, Adele; Belbahri, Lassaad; Cooke, David; Kageyama, Koji; Uematsu, Seiji; Kurbetli, Ilker; Değirmenci, Kemal

    2014-01-01

    A non-papillate, heterothallic Phytophthora species first isolated in 2001 and subsequently from symptomatic roots, crowns and stems of 33 plant species in 25 unrelated botanical families from 13 countries is formally described here as a new species. Symptoms on various hosts included crown and stem rot, chlorosis, wilting, leaf blight, cankers and gumming. This species was isolated from Australia, Hungary, Israel, Italy, Japan, the Netherlands, Norway, South Africa, Spain, Taiwan, Turkey, the United Kingdom and United States in association with shrubs and herbaceous ornamentals grown mainly in greenhouses. The most prevalent hosts are English ivy (Hedera helix) and Cistus (Cistus salvifolius). The association of the species with acorn banksia (Banksia prionotes) plants in natural ecosystems in Australia, in affected vineyards (Vitis vinifera) in South Africa and almond (Prunus dulcis) trees in Spain and Turkey in addition to infection of shrubs and herbaceous ornamentals in a broad range of unrelated families are a sign of a wide ecological adaptation of the species and its potential threat to agricultural and natural ecosystems. The morphology of the persistent non-papillate ellipsoid sporangia, unique toruloid lobate hyphal swellings and amphigynous antheridia does not match any of the described species. Phylogenetic analysis based on sequences of the ITS rDNA, EF-1α, and β-tub supported that this organism is a hitherto unknown species. It is closely related to species in ITS clade 7b with the most closely related species being P. sojae. The name Phytophthora niederhauserii has been used in previous studies without the formal description of the holotype. This name is validated in this manuscript with the formal description of Phytophthora niederhauserii Z.G. Abad et J.A. Abad, sp. nov. The name is coined to honor Dr John S. Niederhauser, a notable plant pathologist and the 1990 World Food Prize laureate.

  14. In vitro shoot proliferation and in vitro and ex vitro root formation of Pyrus elaeagrifolia Pallas

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    Ahmet eAygun

    2015-03-01

    Full Text Available Shoot-tip cultures of Pyrus elaeagrifolia Pallas, an important gene source for drought and chlorosis resistance in pear rootstock breeding, were established from a wild mature tree originated from seed. Murashige and Skoog (MS basal medium supplemented with different concentrations of benzyladenine (BA singly or in combination with auxin was used in the study. In the initial culture, the highest percentages (> 80 % of shoot proliferation were obtained in the mediums supplemented with 9.0 µM BA x 0.5 µM auxin combination and 0.5 µM indole-3-acetic acid . In the subcultures, the highest shoot proliferation rates were obtained in the medium containing 4.5 and 9.0 µM BA. The shoot proliferation rates ranged from 91.1% to 96.4% in the second subculture and from 76.7 to 89.4% in the third subculture. In the second subculture, the shoots grown on 9.0 µM BA without auxin produced the best proliferation (10.6. For the in vitro rooting experiments, the highest rooting rate (54.2%, root length (10.5 mm and root number (2.5 were obtained from 10 days dark treatment on the medium containing half strength of macronutrients supplemented with 5 µM indole-3-butyric acid (IBA. For the ex vitro rooting experiments, shoot rooting was significantly influenced by 10 mM IBA applied as quick-dip method. The percentage of rooting was 55% and root number was 1.8 at this concentration.

  15. Photomorphogenesis and photoassimilation in soybean and sorghum grown under broad spectrum or blue-deficient light sources

    Science.gov (United States)

    Britz, S. J.; Sager, J. C.; Knott, W. M. (Principal Investigator)

    1990-01-01

    The role of blue light in plant growth and development was investigated in soybean (Glycine max [L.] Merr. cv Williams) and sorghum (Sorghum bicolor [L.] Moench. cv Rio) grown under equal photosynthetic photon fluxes (approximately 500 micromoles per square meter per second) from broad spectrum daylight fluorescent or blue-deficient, narrow-band (589 nanometers) low pressure sodium (LPS) lamps. Between 14 and 18 days after sowing, it was possible to relate adaptations in photosynthesis and leaf growth to dry matter accumulation. Soybean development under LPS light was similar in several respects to that of shaded plants, consistent with an important role for blue light photoreceptors in regulation of growth response to irradiance. Thus, soybeans from LPS conditions partitioned relatively more growth to leaves and maintained higher average leaf area ratios (mean LAR) that compensated lower net assimilation rates (mean NAR). Relative growth rates were therefore comparable to plants from daylight fluorescent lamps. Reductions in mean NAR were matched by lower rates of net photosynthesis (A) on an area basis in the major photosynthetic source (first trifoliolate) leaf. Lower A in soybean resulted from reduced leaf dry matter per unit leaf area, but lower A under LPS conditions in sorghum correlated with leaf chlorosis and reduced total nitrogen (not observed in soybean). In spite of a lower A, mean NAR was larger in sorghum from LPS conditions, resulting in significantly greater relative growth rates (mean LAR was approximately equal for both light conditions). Leaf starch accumulation rate was higher for both species and starch content at the end of the dark period was elevated two- and three-fold for sorghum and soybean, respectively, under LPS conditions. Possible relations between starch accumulation, leaf export, and plant growth in response to spectral quality were considered.

  16. Variations in metal tolerance and accumulation in three hydroponically cultivated varieties of Salix integra treated with lead.

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    Shufeng Wang

    Full Text Available Willow species have been suggested for use in the remediation of contaminated soils due to their high biomass production, fast growth, and high accumulation of heavy metals. The tolerance and accumulation of metals may vary among willow species and varieties, and the assessment of this variability is vital for selecting willow species/varieties for phytoremediation applications. Here, we examined the variations in lead (Pb tolerance and accumulation of three cultivated varieties of Salix integra (Weishanhu, Yizhibi and Dahongtou, a shrub willow native to northeastern China, using hydroponic culture in a greenhouse. In general, the tolerance and accumulation of Pb varied among the three willow varieties depending on the Pb concentration. All three varieties had a high tolerance index (TI and EC50 value (the effective concentration of Pb in the nutrient solution that caused a 50% inhibition on biomass production, but a low translocation factor (TF, indicating that Pb sequestration is mainly restricted in the roots of S. integra. Among the three varieties, Dahogntou was more sensitive to the increased Pb concentration than the other two varieties, with the lowest EC50 and TI for root and above-ground tissues. In this respect, Weishanhu and Yizhibi were more suitable for phytostabilization of Pb-contaminated soils. However, our findings also indicated the importance of considering the toxicity symptoms when selecting willow varieties for the use of phytoremediation, since we also found that the three varieties revealed various toxicity symptoms of leaf wilting, chlorosis and inhibition of shoot and root growth under the higher Pb concentrations. Such symptoms could be considered as a supplementary index in screening tests.

  17. Physiological and biochemical mechanisms preventing Cd-toxicity in the hyperaccumulator Atriplex halimus L.

    Science.gov (United States)

    Mesnoua, Mohammed; Mateos-Naranjo, Enrique; Barcia-Piedras, José María; Pérez-Romero, Jesús Alberto; Lotmani, Brahim; Redondo-Gómez, Susana

    2016-09-01

    The xero-halophyte Atriplex halimus L., recently described as Cd-hyperaccumulator, was examined to determine Cd toxicity threshold and the physiological mechanisms involved in Cd tolerance. An experiment was conducted to investigate the effect of cadmium from 0 to 1350 μM on chlorophyll fluorescence parameters, gas exchange, photosynthetic pigment concentrations and antioxidative enzyme activities of A. halimus. Cadmium, calcium, iron, manganese, magnesium, potassium, phosphorous, sodium and zinc concentrations were also analyzed. Plants of A. halimus were not able to survive at 1350 μM Cd and the upper tolerance limit was recorded at 650 μM Cd; although chlorosis was observed from 200 μM Cd. Cadmium accumulation increased with increase in Cd supply, reaching maxima of 0.77 and 4.65 mg g(-1) dry weight in shoots and roots, respectively, at 650 μM Cd. Dry mass, shoot length, specific leaf area, relative growth rate, net photosynthetic rate, stomatal conductance, pigments contents and chlorophyll fluorescence were significantly reduced by increasing Cd concentration. However, the activities of superoxide dismutase (SOD; EC1.15.1.1), catalase (CAT; EC1.11.1.6) and guaiacol peroxidase (GPx; EC1.11.1.7) were significantly induced by Cd. Exposures to Cd caused also a significant decrease in P contents in roots, Mg and Mn contents in shoots and Fe and K contents in roots and shoots and had no effect on Ca, Na and Zn contents. The tolerance of A. halimus to Cd stress might be related with its capacity to avoid the translocation of great amounts of Cd in its aboveground tissues and higher activities of enzymatic antioxidants in the leaf.

  18. Recovery of duckweed from time-varying exposure to atrazine.

    Science.gov (United States)

    Brain, Richard A; Hosmer, Alan J; Desjardins, Debbie; Kendall, Timothy Z; Krueger, Henry O; Wall, Steven B

    2012-05-01

    The purpose of the present study was to evaluate the recovery of duckweed (Lemna gibba L. G3) after being removed from multiple duration exposures to the herbicide atrazine. Consequently, L. gibba were exposed under various scenarios to atrazine at nominal concentrations ranging from 5 to 160 µg/L and durations of 1, 3, 5, 7, 9, and 14 d under static-renewal test conditions. Exposures were followed by a recovery phase in untreated media for either 7 or 14 d. The 3-, 5-, 7-, 9-, and 14-d median effective concentration (EC50) values were >137, >137, 124, >77, and >75 µg/L, respectively, based on mean growth rate. No clear effect trends were apparent between exposure duration and the magnitude of effective concentrations (EC50s or EC10s). No phytocidal effects of chlorosis or necrosis were identified for any treatment scenario. Nearly all L. gibba plants transferred from treatment groups of different exposure scenarios to media without atrazine during the recovery phase had growth rates that demonstrated immediate recovery, indicating effects were phytostatic in nature and reversible. Only the 1- and 5-d exposure scenarios had growth rates indicating marginally prolonged recovery at the higher concentrations (160 µg/L; additionally, at 40 µg/L for the 5-d exposure). Time to recovery, therefore, was found to be largely independent of exposure duration except at the highest concentrations assessed. Based on growth rate by interval, all treatments demonstrated recovery by the final assessment interval (days 5-7), indicating complete recovery in all exposure scenarios by 7 d, consistent with the mode of action of atrazine. PMID:22431202

  19. Different zinc sensitivity of Brassica organs is accompanied by distinct responses in protein nitration level and pattern.

    Science.gov (United States)

    Feigl, Gábor; Kolbert, Zsuzsanna; Lehotai, Nóra; Molnár, Árpád; Ördög, Attila; Bordé, Ádám; Laskay, Gábor; Erdei, László

    2016-03-01

    Zinc is an essential microelement, but its excess exerts toxic effects in plants. Heavy metal stress can alter the metabolism of reactive oxygen (ROS) and nitrogen species (RNS) leading to oxidative and nitrosative damages; although the participation of these processes in Zn toxicity and tolerance is not yet known. Therefore this study aimed to evaluate the zinc tolerance of Brassica organs and the putative correspondence of it with protein nitration as a relevant marker for nitrosative stress. Both examined Brassica species (B. juncea and B. napus) proved to be moderate Zn accumulators; however B. napus accumulated more from this metal in its organs. The zinc-induced damages (growth diminution, altered morphology, necrosis, chlorosis, and the decrease of photosynthetic activity) were slighter in the shoot system of B. napus than in B. juncea. The relative zinc tolerance of B. napus shoot was accompanied by moderate changes of the nitration pattern. In contrast, the root system of B. napus suffered more severe damages (growth reduction, altered morphology, viability loss) and slighter increase in nitration level compared to B. juncea. Based on these, the organs of Brassica species reacted differentially to excess zinc, since in the shoot system modification of the nitration pattern occurred (with newly appeared nitrated protein bands), while in the roots, a general increment in the nitroproteome could be observed (the intensification of the same protein bands being present in the control samples). It can be assumed that the significant alteration of nitration pattern is coupled with enhanced zinc sensitivity of the Brassica shoot system and the general intensification of protein nitration in the roots is attached to relative zinc endurance.

  20. Selected Morphological Characteristics, Lead Uptake and Phytochelatin Synthesis by Coffeeweed (Sesbania exaltata Raf. Grown in Elevated Levels of Lead-Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Maria F. T. Begonia

    2011-06-01

    Full Text Available Remediation of lead-contaminated soil is significant due to the inherent toxicity of lead (Pb, and the quantity of Pb discharged into the soil. One of the most cost-effective and environmentally sound technologies for the cleanup of metal-contaminated soils is through the use of plants. While much is known about the ecological evolution of metal tolerance in plants, the physiological, biochemical, and genetic mechanisms of tolerance is not well understood in the majority of resistant ecotypes such as the legume, Sesbania exaltata Raf. This study was therefore conducted to determine the morphological and physiological characteristics of Sesbania that had been grown in Pb-contaminated soil, and to assess phytochelatin synthesis as a way of elucidating its relative Pb tolerance. Sesbania plants were grown in the greenhouse and exposed to various levels of Pb: 0, 1000, and 2000 mg Pb/kg soil. Plants were harvested after 6, 8, and 10 weeks of growth and morphological characteristics (e.g., root and shoot biomass, root length, number of root nodules, shoot height, number of leaves, number of flowers, number and length of pods were recorded. Generally, there were no statistical differences in morphological characteristics among the treatments. Further, no discernible phytotoxic symptoms, such as chlorosis, wilting, or necrotic lesions, in neither roots nor shoots were observed. We concluded that while Sesbania did not fit the model of a hyperaccumulator, the plant was, nonetheless, tolerant to elevated Pb levels. Our assessment for phytochelatin synthesis as a tolerance mechanism was inconclusive and further investigations of tolerance mechanisms are warranted.

  1. Lead detoxification by coontail (Ceratophyllum demersum L.) involves induction of phytochelatins and antioxidant system in response to its accumulation.

    Science.gov (United States)

    Mishra, Seema; Srivastava, S; Tripathi, R D; Kumar, R; Seth, C S; Gupta, D K

    2006-11-01

    Coontail (Ceratophyllum demersum L.) plants when exposed to various concentrations of Pb (1-100microM) for 1-7days, exhibited both phytotoxic and tolerance responses. The specific responses were function of concentration and duration. Plants accumulated 1748mugPbg(-1) dw after 7d which reflected its metal accumulation ability, however most of the metal (1222microgg(-1) dw, 70%) was accumulated after 1d exposure only. The toxic effect and oxidative stress caused by Pb were evident by the reduction in biomass and photosynthetic pigments and increase in malondialddehyde (MDA) content and electrical conductivity with increase in metal concentration and exposure duration. Morphological symptoms of senescence phenomena such as chlorosis and fragmentation of leaves were observed after 7d. The metal tolerance and detoxification strategy adopted by the plant was investigated with reference to antioxidant system and synthesis of phytochelatins. Protein and antioxidant enzymes viz., superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (GPX, EC 1.11.1.7) ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6) and glutathione reductase (GR, EC 1.6.4.2) showed induction at lower concentration and duration followed by decline. All enzymes except GPX showed maximum activity after 1d. An increase in cysteine, non-protein thiols (NP-SH) and glutathione (GSH) content was observed at moderate exposure conditions followed by decline. Phytochelatins (PC(2) and PC(3)) were synthesized to significant levels at 10 and 50microM Pb with concomitant decrease in GSH levels. Thus production of PCs seems important for the detoxification of metal, however it may lead to depletion of GSH and consequently oxidative stress. Results suggest that plants responded positively to moderate Pb concentrations and accumulated high amount of metal. Due to metal accumulation coupled with detoxification potential, the plant appears to have potential for its use as phytoremediator species

  2. Selected morphological characteristics, lead uptake and phytochelatin synthesis by coffeeweed (Sesbania exaltata Raf.) grown in elevated levels of lead-contaminated soil.

    Science.gov (United States)

    Miller, Gloria; Begonia, Gregorio; Begonia, Maria F T

    2011-06-01

    Remediation of lead-contaminated soil is significant due to the inherent toxicity of lead (Pb), and the quantity of Pb discharged into the soil. One of the most cost-effective and environmentally sound technologies for the cleanup of metal-contaminated soils is through the use of plants. While much is known about the ecological evolution of metal tolerance in plants, the physiological, biochemical, and genetic mechanisms of tolerance is not well understood in the majority of resistant ecotypes such as the legume, Sesbania exaltata Raf. This study was therefore conducted to determine the morphological and physiological characteristics of Sesbania that had been grown in Pb-contaminated soil, and to assess phytochelatin synthesis as a way of elucidating its relative Pb tolerance. Sesbania plants were grown in the greenhouse and exposed to various levels of Pb: 0, 1000, and 2000 mg Pb/kg soil. Plants were harvested after 6, 8, and 10 weeks of growth and morphological characteristics (e.g., root and shoot biomass, root length, number of root nodules, shoot height, number of leaves, number of flowers, number and length of pods) were recorded. Generally, there were no statistical differences in morphological characteristics among the treatments. Further, no discernible phytotoxic symptoms, such as chlorosis, wilting, or necrotic lesions, in neither roots nor shoots were observed. We concluded that while Sesbania did not fit the model of a hyperaccumulator, the plant was, nonetheless, tolerant to elevated Pb levels. Our assessment for phytochelatin synthesis as a tolerance mechanism was inconclusive and further investigations of tolerance mechanisms are warranted.

  3. Directed evolution induces tributyrin hydrolysis in a virulence factor of Xylella fastidiosa using a duplicated gene as a template [v1; ref status: indexed, http://f1000r.es/48i

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    Hossein Gouran

    2014-09-01

    Full Text Available Duplication of genes is one of the preferred ways for natural selection to add advantageous functionality to the genome without having to reinvent the wheel with respect to catalytic efficiency and protein stability. The duplicated secretory virulence factors of Xylella fastidiosa (LesA, LesB and LesC, implicated in Pierce's disease of grape and citrus variegated chlorosis of citrus species, epitomizes the positive selection pressures exerted on advantageous genes in such pathogens. A deeper insight into the evolution of these lipases/esterases is essential to develop resistance mechanisms in transgenic plants. Directed evolution, an attempt to accelerate the evolutionary steps in the laboratory, is inherently simple when targeted for loss of function. A bigger challenge is to specify mutations that endow a new function, such as a lost functionality in a duplicated gene. Previously, we have proposed a method for enumerating candidates for mutations intended to transfer the functionality of one protein into another related protein based on the spatial and electrostatic properties of the active site residues (DECAAF. In the current work, we present in vivo validation of DECAAF by inducing tributyrin hydrolysis in LesB based on the active site similarity to LesA. The structures of these proteins have been modeled using RaptorX based on the closely related LipA protein from Xanthomonas oryzae. These mutations replicate the spatial and electrostatic conformation of LesA in the modeled structure of the mutant LesB as well, providing in silico validation before proceeding to the laborious in vivo work. Such focused mutations allows one to dissect the relevance of the duplicated genes in finer detail as compared to gene knockouts, since they do not interfere with other moonlighting functions, protein expression levels or protein-protein interaction.

  4. Global gene expression under nitrogen starvation in Xylella fastidiosa: contribution of the σ54 regulon

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    da Silva Neto José F

    2010-08-01

    Full Text Available Abstract Background Xylella fastidiosa, a Gram-negative fastidious bacterium, grows in the xylem of several plants causing diseases such as citrus variegated chlorosis. As the xylem sap contains low concentrations of amino acids and other compounds, X. fastidiosa needs to cope with nitrogen limitation in its natural habitat. Results In this work, we performed a whole-genome microarray analysis of the X. fastidiosa nitrogen starvation response. A time course experiment (2, 8 and 12 hours of cultures grown in defined medium under nitrogen starvation revealed many differentially expressed genes, such as those related to transport, nitrogen assimilation, amino acid biosynthesis, transcriptional regulation, and many genes encoding hypothetical proteins. In addition, a decrease in the expression levels of many genes involved in carbon metabolism and energy generation pathways was also observed. Comparison of gene expression profiles between the wild type strain and the rpoN null mutant allowed the identification of genes directly or indirectly induced by nitrogen starvation in a σ54-dependent manner. A more complete picture of the σ54 regulon was achieved by combining the transcriptome data with an in silico search for potential σ54-dependent promoters, using a position weight matrix approach. One of these σ54-predicted binding sites, located upstream of the glnA gene (encoding glutamine synthetase, was validated by primer extension assays, confirming that this gene has a σ54-dependent promoter. Conclusions Together, these results show that nitrogen starvation causes intense changes in the X. fastidiosa transcriptome and some of these differentially expressed genes belong to the σ54 regulon.

  5. A Novel Function for Arabidopsis CYCLASE1 in Programmed Cell Death Revealed by Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Analysis of Extracellular Matrix Proteins.

    Science.gov (United States)

    Smith, Sarah J; Kroon, Johan T M; Simon, William J; Slabas, Antoni R; Chivasa, Stephen

    2015-06-01

    Programmed cell death is essential for plant development and stress adaptation. A detailed understanding of the signal transduction pathways that regulate plant programmed cell death requires identification of the underpinning protein networks. Here, we have used a protagonist and antagonist of programmed cell death triggered by fumonisin B1 as probes to identify key cell death regulatory proteins in Arabidopsis. Our hypothesis was that changes in the abundance of cell death-regulatory proteins induced by the protagonist should be blocked or attenuated by concurrent treatment with the antagonist. We focused on proteins present in the mobile phase of the extracellular matrix on the basis that they are important for cell-cell communications during growth and stress-adaptive responses. Salicylic acid, a plant hormone that promotes programmed cell death, and exogenous ATP, which can block fumonisin B1-induced cell death, were used to treat Arabidopsis cell suspension cultures prior to isobaric-tagged relative and absolute quantitation analysis of secreted proteins. A total of 33 proteins, whose response to salicylic acid was suppressed by ATP, were identified as putative cell death-regulatory proteins. Among these was CYCLASE1, which was selected for further analysis using reverse genetics. Plants in which CYCLASE1 gene expression was knocked out by insertion of a transfer-DNA sequence manifested dramatically increased cell death when exposed to fumonisin B1 or a bacterial pathogen that triggers the defensive hypersensitive cell death. Although pathogen inoculation altered CYCLASE1 gene expression, multiplication of bacterial pathogens was indistinguishable between wild type and CYCLASE1 knockout plants. However, remarkably severe chlorosis symptoms developed on gene knockout plants in response to inoculation with either a virulent bacterial pathogen or a disabled mutant that is incapable of causing disease in wild type plants. These results show that CYCLASE1, which

  6. Beneficial effects of humic acid on micronutrient availability to wheat

    Science.gov (United States)

    Mackowiak, C. L.; Grossl, P. R.; Bugbee, B. G.

    2001-01-01

    Humic acid (HA) is a relatively stable product of organic matter decomposition and thus accumulates in environmental systems. Humic acid might benefit plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA on growth and micronutrient uptake in wheat (Triticum aestivum L.) grown hydroponically. Four root-zone treatments were compared: (i) 25 micromoles synthetic chelate N-(4-hydroxyethyl)ethylenediaminetriacetic acid (C10H18N2O7) (HEDTA at 0.25 mM C); (ii) 25 micromoles synthetic chelate with 4-morpholineethanesulfonic acid (C6H13N4S) (MES at 5 mM C) pH buffer; (iii) HA at 1 mM C without synthetic chelate or buffer; and (iv) no synthetic chelate or buffer. Ample inorganic Fe (35 micromoles Fe3+) was supplied in all treatments. There was no statistically significant difference in total biomass or seed yield among treatments, but HA was effective at ameliorating the leaf interveinal chlorosis that occurred during early growth of the nonchelated treatment. Leaf-tissue Cu and Zn concentrations were lower in the HEDTA treatment relative to no chelate (NC), indicating HEDTA strongly complexed these nutrients, thus reducing their free ion activities and hence, bioavailability. Humic acid did not complex Zn as strongly and chemical equilibrium modeling supported these results. Titration tests indicated that HA was not an effective pH buffer at 1 mM C, and higher levels resulted in HA-Ca and HA-Mg flocculation in the nutrient solution.

  7. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    Science.gov (United States)

    Muranaka, Lígia S; Giorgiano, Thais E; Takita, Marco A; Forim, Moacir R; Silva, Luis F C; Coletta-Filho, Helvécio D; Machado, Marcos A; de Souza, Alessandra A

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria. PMID:24009716

  8. The role of autophagy in chloroplast degradation and chlorophagy in immune defenses during Pst DC3000 (AvrRps4 infection.

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    Junjian Dong

    Full Text Available BACKGROUND: Chlorosis of leaf tissue normally observed during pathogen infection may result from the degradation of chloroplasts. There is a growing evidence to suggest that the chloroplast plays a significant role during pathogen infection. Although most degradation of the organelles and cellular structures in plants is mediated by autophagy, its role in chloroplast catabolism during pathogen infection is largely unknown. RESULTS: In this study, we investigated the function of autophagy in chloroplast degradation during avirulent Pst DC3000 (AvrRps4 infection. We examined the expression of defensive marker genes and suppression of bacterial growth using the electrolyte leakage assay in normal light (N and low light (L growing environments of wild-type and atg5-1 plants during pathogen treatment. Stroma-targeted GFP proteins (CT-GFP were observed with LysoTracker Red (LTR staining of autophagosome-like structures in the vacuole. The results showed that Arabidopsis expressed a significant number of small GFP-labeled bodies when infected with avirulent Pst DC3000 (AvrRps4. While barely detectable, there were small GFP-labeled bodies in plants with the CT-GFP expressing atg5-1 mutation. The results showed that chloroplast degradation depends on autophagy and this may play an important role in inhibiting pathogen growth. CONCLUSION: Autophagy plays a role in chloroplast degradation in Arabidopsis during avirulent Pst DC3000 (AvrRps4 infection. Autophagy dependent chloroplast degradation may be the primary source of reactive oxygen species (ROS as well as the pathogen-response signaling molecules that induce the defense response.

  9. Toxicity of zinc and copper to Brassica species: Implications for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Ebbs, S.D.; Kochian, L.V. [Cornell Univ., Ithaca, NY (United States)

    1997-05-01

    The toxicity of Zn and Cu in three species from the genus Brassica was examined to determine if these plants showed sufficient tolerance and metal accumulation to be used to phytoremediate a site contaminated with these two heavy metals. Hydroponically grown 12-d-old plants of Brassica juncea, B. rapa, and B. napus were grown for an additional 14 d in the presence of either elevated Zn (6.5 mg L{sup {minus}1}), Cu (0.32 mg L{sup {minus}1}), or Zn+Cu to quantify the toxic effects of these metals on several different growth parameters. With few exceptions, both root and shoot dry weight for all three species decreased significantly in the presence of heavy metals. Cu inhibited lateral root elongation in B. rapa, B. napus, and, to a lesser extent, B. juncea, while Zn tended to decrease only lateral root diameter. Both metals reduced shoot Fe and Mn concentrations in all three Brassica spp. to levels associated with Fe and Mn deficiencies. These deficiencies, however, did not correlate with observed patterns of leaf chlorosis. Nonetheless, heavy metal-induced inhibition of Fe and Mn accumulation may have been a significant factor in reducing plant growth. In terms of heavy metal removal, the Brassica spp, were more effective at removing Zn from the nutrient solution than Cu. The extent of Zn and Cu removal was reduced in the presence of both metals, as compared to the single heavy metal treatments. The implications of these results for phytoremediation are discussed. 20 refs., 6 figs., 1 tab.

  10. Response of turnips to chronic doses of ozone in open-top field chambers

    Energy Technology Data Exchange (ETDEWEB)

    Heagle, A.S.; Cure, W.W.; Rawlings, J.O.

    1985-01-01

    Turnips Brassica rapa L., were exposed to chronic doses of ozone (O3) by adding different amounts of O3 for 7 h a day to non-filtered air in open-top field chambers. One cultivar (Tokyo Cross) was tested in 1979 and four cultivars (Tokyo Cross, Shogoin, Purple Top White Globe and Just Right) in 1980. Ambient levels of O3 usually did not affect shoot or root weight in either year. In 1979, seasonal mean O3 levels greater than ambient caused greater percentage growth decreases of Tokyo Cross plants grown in the ground than for plants grown in 3.8 liter pots. In 1980, 7 h a day exposures from 20 October to 14 November to levels as high as 0.16 ppm caused some chlorosis on a few of the oldest leaves of all cultivars. No O3 was added from 15-17 November because the weather was cold, overcast and rainy. Exposures to O3 concentrations of 0.09 or 0.11 ppm for 3 - 5 h on the afternoon of 18 November caused severe foliar necrosis on all expanded leaves of all cultivars. The Weibull survival function was used to predict root weight decreases at different seasonal 7 h a day mean O3 levels using 0.025 ppm O3 as the control. Predicted percentage root weight losses for the four cultivars combined at seasonal O3 levels of 0.04, 0.06 and 0.08 ppm were 7, 24 and 47%, respectively.

  11. The effects of foliar fertilization with iron sulfate in chlorotic leaves are limited to the treated area. A study with peach trees (Prunus persica L. Batsch) grown in the field and sugar beet (Beta vulgaris L.) grown in hydroponics.

    Science.gov (United States)

    El-Jendoubi, Hamdi; Vázquez, Saúl; Calatayud, Angeles; Vavpetič, Primož; Vogel-Mikuš, Katarina; Pelicon, Primož; Abadía, Javier; Abadía, Anunciación; Morales, Fermín

    2014-01-01

    Crop Fe deficiency is a worldwide problem. The aim of this study was to assess the effects of foliar Fe applications in two species grown in different environments: peach (Prunus persica L. Batsch) trees grown in the field and sugar beet (Beta vulgaris L. cv. "Orbis") grown in hydroponics. The distal half of Fe-deficient, chlorotic leaves was treated with Fe sulfate by dipping and using a brush in peach trees and sugar beet plants, respectively. The re-greening of the distal (Fe-treated) and basal (untreated) leaf areas was monitored, and the nutrient and photosynthetic pigment composition of the two areas were also determined. Leaves were also studied using chlorophyll fluorescence imaging, low temperature-scanning electron microscopy microanalysis, scanning transmission ion microscopy-particle induced X-ray emission and Perls Fe staining. The distal, Fe-treated leaf parts of both species showed a significant increase in Fe concentrations (across the whole leaf volume) and marked re-greening, with significant increases in the concentrations of all photosynthetic pigments, as well as decreases in de-epoxidation of xanthophyll cycle carotenoids and increases in photochemical efficiency. In the basal, untreated leaf parts, Fe concentrations increased slightly, but little re-greening occurred. No changes in the concentrations of other nutrients were found. Foliar Fe fertilization was effective in re-greening treated leaf areas both in peach trees and sugar beet plants. Results indicate that the effects of foliar Fe-sulfate fertilization in Fe-deficient, chlorotic leaves were minor outside the leaf surface treated, indicating that Fe mobility within the leaf is a major constraint for full fertilizer effectiveness in crops where Fe-deficiency is established and leaf chlorosis occurs.

  12. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    Science.gov (United States)

    Muranaka, Lígia S; Giorgiano, Thais E; Takita, Marco A; Forim, Moacir R; Silva, Luis F C; Coletta-Filho, Helvécio D; Machado, Marcos A; de Souza, Alessandra A

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria.

  13. The effects of foliar fertilization with iron sulfate in chlorotic leaves are limited to the treated area. A study with peach trees (Prunus persica L. Batsch grown in the field and sugar beet (Beta vulgaris L. grown in hydroponics

    Directory of Open Access Journals (Sweden)

    Hamdi eEl-Jendoubi

    2014-01-01

    Full Text Available Crop Fe deficiency is a worldwide problem. The aim of this study was to assess the effects of foliar Fe applications in two species grown in different environments: peach (Prunus persica L. Batsch trees grown in the field and sugar beet (Beta vulgaris L. cv. ‘Orbis’ grown in hydroponics. The distal half of Fe-deficient, chlorotic leaves was treated with Fe sulfate by dipping and using a brush in peach trees and sugar beet plants, respectively. The re-greening of the distal (Fe-treated and basal (untreated leaf areas was monitored, and the nutrient and photosynthetic pigment composition of the two areas were also determined. Leaves were also studied using chlorophyll fluorescence imaging, low temperature-scanning electron microscopy microanalysis, scanning transmission ion microscopy-particle induced X-ray emission and Perls Fe staining. The distal, Fe-treated leaf parts of both species showed a significant increase in Fe concentrations (across the whole leaf volume and marked re-greening, with significant increases in the concentrations of all photosynthetic pigments, as well as decreases in de-epoxidation of xanthophyll cycle carotenoids and increases in photochemical efficiency. In the basal, untreated leaf parts, Fe concentrations increased slightly, but little re-greening occurred. No changes in the concentrations of other nutrients were found. Foliar Fe fertilization was effective in re-greening treated leaf areas both in peach trees and sugar beet plants. Results indicate that the effects of foliar Fe-sulfate fertilization in Fe-deficient, chlorotic leaves were minor outside the leaf surface treated, indicating that Fe mobility within the leaf is a major constraint for full fertilizer effectiveness in crops where Fe-deficiency is established and leaf chlorosis occurs.

  14. The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

    Science.gov (United States)

    Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

    2012-09-01

    Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under

  15. Identification of CBF14 and NAC2 Genes in Aegilops tauschii Associated with Resistance to Freezing Stress.

    Science.gov (United States)

    Masoomi-Aladizgeh, Farhad; Aalami, Ali; Esfahani, Masoud; Aghaei, Mohamad Jaafar; Mozaffari, Khadijeh

    2015-06-01

    Low temperature as one of the most important environmental factors limits the productivity of plants across the world. Aegilops, as a wild species of Poaceae, contains low temperature-responsive genes. In this study, we analyzed morphological (wilting, chlorosis, and recovery) and physiological (ion leakage) characteristics to identification of a cold-tolerant genotype. In this experiment, we introduced two transcription factors (TFs) in Aegilops species for the first time. Bioinformatics analysis demonstrated that our nucleotide sequences have high similarity with CBF14 (C-repeat-binding factor) and NAC2 (NAM, ATAF, and CUC) in Triticum aestivum. Based on the physiological and morphological data, one genotype (Aladizgeh) was identified as the most resistant genotype which was selected for further gene expression analysis. The real-time PCR results indicated that the CBF14 gene was not expressed 3 h following cold treatment, but the highest expression was observed after 6, 12, and 24 h of cold treatment; however, a sudden decrease was observed in its expression after 30 h. The NAC2 gene also was not expressed 3 h after cold stress, but the highest expression was at 24 h and similar to the CBF14 gene; its expression suddenly decreased after 30 h. Our results indicated that this genotype can tolerate -4 °C for 3 h, but the CBF14 and NAC2 genes were activated when treated for longer durations. Expression of TFs studied in this experiment had decreased after 30 h, in which cell death seems to be the important reason.

  16. Variation in susceptibility to Wheat dwarf virus among wild and domesticated wheat.

    Directory of Open Access Journals (Sweden)

    Jim Nygren

    Full Text Available We investigated the variation in plant response in host-pathogen interactions between wild (Aegilops spp., Triticum spp. and domesticated wheat (Triticum spp. and Wheat dwarf virus (WDV. The distribution of WDV and its wild host species overlaps in Western Asia in the Fertile Crescent, suggesting a coevolutionary relationship. Bread wheat originates from a natural hybridization between wild emmer wheat (carrying the A and B genomes and the wild D genome donor Aegilops tauschii, followed by polyploidization and domestication. We studied whether the strong selection during these evolutionary processes, leading to genetic bottlenecks, may have resulted in a loss of resistance in domesticated wheat. In addition, we investigated whether putative fluctuations in intensity of selection imposed on the host-pathogen interactions have resulted in a variation in susceptibility to WDV. To test our hypotheses we evaluated eighteen wild and domesticated wheat taxa, directly or indirectly involved in wheat evolution, for traits associated with WDV disease such as leaf chlorosis, different growth traits and WDV content. The plants were exposed to viruliferous leafhoppers (Psammotettix alienus in a greenhouse trial and evaluated at two time points. We found three different plant response patterns: i continuous reduction in growth over time, ii weak response at an early stage of plant development but a much stronger response at a later stage, and iii remission of symptoms over time. Variation in susceptibility may be explained by differences in the intensity of natural selection, shaping the coevolutionary interaction between WDV and the wild relatives. However, genetic bottlenecks during wheat evolution have not had a strong impact on WDV resistance. Further, this study indicates that the variation in susceptibility may be associated with the genome type and that the ancestor Ae. tauschii may be useful as genetic resource for the improvement of WDV resistance in

  17. Hypersensitive response-like reaction is associated with hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii coss.

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    Nobuyuki Mizuno

    Full Text Available BACKGROUND: Hybrid speciation is classified into homoploid and polyploid based on ploidy level. Common wheat is an allohexaploid species that originated from a naturally occurring interploidy cross between tetraploid wheat and diploid wild wheat Aegilops tauschii Coss. Aegilops tauschii provides wide naturally occurring genetic variation. Sometimes its triploid hybrids with tetraploid wheat show the following four types of hybrid growth abnormalities: types II and III hybrid necrosis, hybrid chlorosis, and severe growth abortion. The growth abnormalities in the triploid hybrids could act as postzygotic hybridization barriers to prevent formation of hexaploid wheat. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report on the geographical and phylogenetic distribution of Ae. tauschii accessions inducing the hybrid growth abnormalities and showed that they are widely distributed across growth habitats in Ae. tauschii. Molecular and cytological characterization of the type III necrosis phenotype was performed. The hybrid abnormality causing accessions were widely distributed across growth habitats in Ae. tauschii. Transcriptome analysis showed that a number of defense-related genes such as pathogenesis-related genes were highly up-regulated in the type III necrosis lines. Transmission electron microscope observation revealed that cell death occurred accompanied by generation of reactive oxygen species in leaves undergoing type III necrosis. The reduction of photosynthetic activity occurred prior to the appearance of necrotic symptoms on the leaves exhibiting hybrid necrosis. CONCLUSIONS/SIGNIFICANCE: Taking these results together strongly suggests that an autoimmune response might be triggered by intergenomic incompatibility between the tetraploid wheat and Ae. tauschii genomes in type III necrosis, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in Arabidopsis

  18. STUDYING THE INFLUENCE OF FUROLAN, METHIONINE AND THEIR COMPOSITIONS ON THE WATER BALANCE AND ANATOMICAL AND MORPHOLOGICAL CHARACTERISTICS OF WINTER WHEAT LEAVES OF KRASNODARSKAYA 99VARIETY

    Directory of Open Access Journals (Sweden)

    Yablonskaya Y. K.

    2016-02-01

    Full Text Available The plant body cells must contain a certain amount of water for a normal life. Water deficiency in cultivated plants was due to using herbicides used in intensive technologies of cultivation of agricultural crops. The conditions of the environment determine the sensitivity of the plant to herbicide. Soil and climatic conditions of winter wheat grown in the time of herbicide treatment are important for the effectiveness of its actions. It was found, that plants grown under shade or high humidity are more sensitive to herbicides than ones grown in bright sunlight and in times of drought. During drought, and in the open sunny spot, plant development is faster and become more stable. On soils rich in humus, we may grow less herbicide-resistant plants than in soils poor in organic matter. Herbicides are moved through the vascular system of plants with nutrients and metabolic products, they cause general poisoning as deformation of the stem and leaves of the plants, growth inhibition, chlorosis, fragility of leaves and stems, sterility, reducing the amount of free to bound water, which is particularly important for combating perennial weeds that have strong and well-developed root system. Monocots are able to immobilize the leaf herbicides. Latency of herbicides and their immobilization are carried out in various ways. Elucidation of the physiological characteristics that determine the resistance of plants to water scarcity and the effects of the herbicides is the most important task, the solution of which is not only of great theoretical, but also has practical significance

  19. Accumulation, distribution and toxicological effects induced by chromium on the development of mangrove plant Kandelia candel (L. Druce

    Directory of Open Access Journals (Sweden)

    Kazi Shakila Islam

    2009-04-01

    Full Text Available A study was performed for investigating accumulation, distribution and toxicological effects induced by chromium (Cr on the development of the mangrove seedling Kandelia candel (L. Druce. Seedlings treated with increasing concentrations of CrCl3 solution (0, 0.5, 1, 1.5, 2, 2.5, 3 mg L-1, respectively were grown in a basic nutrient solution for three months. The five month old seedlings were harvested for the experiment. This study showed that Cr treatment significantly decreased growth of K. candel in terms of seedling height, leaf number and total biomass. At the highest 3 mg L-1 Cr exposure, there was a 34.47% decrease in final seedling height, 68.95% decrease in leaf number and a 60.65% decrease in total biomass. The present study demonstrates that Cr accumulation ability of K. candel seedlings increased with the increase of treatment strength up to certain level. The concentrations of Cr in root, hypocotyl, stem and leaf ranged from 22.87 to 1.43 mg kg-1, 1.30 to 0.68 mg kg-1, 2.42 to 0.91 mg kg-1, and 1.74 to 0.74 mg kg-1, respectively. When comparing Cr concentration in different plant parts with respect to their controls, the results showed that treated plant root bioaccumulated high amounts of Cr. Almost 80% of Cr was accumulated mainly in roots. The distribution pattern of Cr in K. candel was Root > Stem > Leaf > Hypocotyl. Our findings indicated that the high concentration of Cr supply may interfere with several metabolic processes of seedlings, causing toxicity to plants as exhibited by chlorosis, necrosis, and finally, plant death.

  20. Differential RNAi responses of Nicotiana benthamiana individuals transformed with a hairpin-inducing construct during Plum pox virus challenge.

    Science.gov (United States)

    Montes, Christian; Castro, Álvaro; Barba, Paola; Rubio, Julia; Sánchez, Evelyn; Carvajal, Denisse; Aguirre, Carlos; Tapia, Eduardo; DelÍ Orto, Paola; Decroocq, Veronique; Prieto, Humberto

    2014-10-01

    Gene silencing and large-scale small RNA analysis can be used to develop RNA interference (RNAi)-based resistance strategies for Plum pox virus (PPV), a high impact disease of Prunus spp. In this study, a pPPViRNA hairpin-inducing vector harboring two silencing motif-rich regions of the PPV coat protein (CP) gene was evaluated in transgenic Nicotiana benthamiana (NB) plants. Wild-type NB plants infected with a chimeric PPV virus (PPV::GFP) exhibited affected leaves with mosaic chlorosis congruent to GFP fluorescence at 21 day post-inoculation; transgenic lines depicted a range of phenotypes from fully resistant to susceptible. ELISA values and GFP fluorescence intensities were used to select transgenic-resistant (TG-R) and transgenic-susceptible (TG-S) lines for further characterization of small interfering RNAs (siRNAs) by large-scale small RNA sequencing. In infected TG-S and untransformed (WT) plants, the observed siRNAs were nearly exclusively 21- and 22-nt siRNAs that targeted the whole PPV::GFP genome; 24-nt siRNAs were absent in these individuals. Challenged TG-R plants accumulated a full set of 21- to 24-nt siRNAs that were primarily associated with the selected motif-rich regions, indicating that a trans-acting siRNAs process prevented viral multiplication. BLAST analysis identified 13 common siRNA clusters targeting the CP gene. 21-nt siRNA sequences were associated with the 22-nt siRNAs and the scarce 23- and 24-nt molecules in TG-S plants and with most of the observed 22-, 23-, and 24-nt siRNAs in TG-R individuals. These results validate the use of a multi-hot spot silencing vector against PPV and elucidate the molecules by which hairpin-inducing vectors initiate RNAi in vivo. PMID:24964777

  1. Improved recovery of cryotherapy-treated shoot tips following thermotherapy of in vitro-grown stock shoots of raspberry (Rubus idaeus L.).

    Science.gov (United States)

    Wang, Qiaochun; Valkonen, Jari P T

    2009-01-01

    Raspberry bushy dwarf virus (RBDV) can be efficiently eradicated from raspberry plants (Rubus idaeus) by a procedure combining thermotherapy and cryotherapy. However, the bottleneck of this procedure is that, following thermotherapy, cryopreserved shoot tips become chlorotic during regrowth and eventually die after several subcultures. In addition, survival of heat-treated stock shoots and recovery of cryopreserved shoot tips following thermotherapy are low. The present study focused towards improving regrowth of cryopreserved raspberry shoot tips following thermotherapy. Results showed that preconditioning stock shoots with salicylic acid (SA; 0.01-0.1 mM) markedly increased survival of stock shoots after 4 weeks of thermotherapy. Regrowth of cryopreserved shoot tips following thermotherapy was also significantly enhanced when SA (0.05-0.1 mM) was used for preconditioning stock shoots. Addition of either Fe-ethylenediaminetetracetic acid (Fe-EDTA, 50 mg per L) or Fe-ethylenediaminedi(o)hydroxyphenylacetic acid (Fe-EDDHA, 50 mg per L) to post-culture medium strongly promoted regrowth and totally prevented chlorosis of shoots regenerated from cryopreserved shoot tips following thermotherapy. Using the parameters optimized in the present study, about 80 percent survival of heat-treated stock shoots and about 33 percent regrowth of cryopreserved shoot tips following thermotherapy were obtained. Morphology of plants regenerated from cryopreserved shoot tips following thermotherapy was identical to that of control plants, based on observations of leaf shape and size, internode length and plant height. Optimization of the thermotherapy procedure followed by cryotherapy will facilitate the wider application of this technique to eliminate viruses which can invade meristems.

  2. Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

    Directory of Open Access Journals (Sweden)

    Gustavo Habermann

    2006-01-01

    Full Text Available Citrus variegated chlorosis (CVC is a disease caused by Xylella fastidiosa. Using different concentrations of plant regulators, such as auxins (indole-3-butyric acid and gibberellic acid biosynthesis-inhibitor (paclobutrazol, physiological rooting capacity of healthy and CVC-affected stem cuttings were evaluated in order to investigate the importance of plant hormone imbalance and xylem occlusion in plants with CVC. The percentages of dead, alive and rooted cuttings, cuttings with callus and mean number of roots per cuttings did not show statistical differences in response to the distinct concentrations of synthetic plant regulators. There were differences only between healthy and CVC-affected cuttings. This showed the importance of xylem occlusion and diffusive disturbances in diseased plants, in relation to root initiation capacity and hormonal translocation in the plant tissue.Clorose variegada dos citros (CVC é uma doença causada por Xylella fastidiosa, podendo determinar oclusão do xilema e desbalanço hormonal, o que por fim está relacionado ao processo de iniciação radicial em estacas. Usando diferentes concentrações de fitorreguladores, como auxinas (ácido 3-indol butírico e inibidores da biossíntese de ácido giberélico (paclobutrazol, que são promotores do enraizamento de estacas, verificou-se a capacidade fisiológica de enraizamento de estacas sadias e com CVC, a fim de investigar a importância do desbalanço hormonal e oclusão do xilema em plantas doentes. As porcentagens de estacas mortas, vivas, enraizadas e com calo e o número médio de raízes por estaca não mostraram diferenças estatísticas em resposta às diferentes concentrações dos reguladores vegetais sintéticos. Houve diferenças apenas entre estacas sadias e doentes. Isto aponta a importância da oclusão do xilema e distúrbios difusivos em plantas doentes, em relação à capacidade de iniciação radicial e à translocação hormonal no tecido

  3. An advanced field experimental design to assess plant tolerance to heavy metal pollution

    Science.gov (United States)

    Łopata, Barbara; Szarek-Łukaszewska, Grażyna; Babst-Kostecka, Alicja

    2016-04-01

    the plant development, 2) the percentage of leaves showing visible symptoms of Zn toxicity (i.e. leaf chlorosis, mottling, necrosis, anthocyanescence), and measurement of 3) number of stems, 4) length of the longest stem, 5) effective photosystem II yield, and 6) chlorophyll content. Upon termination of the experiment, we are going to harvest all plant material for genetic, physiological and chemical analyses. This ongoing project is conducted in southern Poland and as a study object we chose the model pseudometallophyte Arabidopsis halleri (Brassicaceae). However, our enhanced experimental design can easily be adapted to other locations and species, thereby facilitating the intercomparisons between results obtained by different researchers and from a variety of geographic locations. The obtained plant material can be used in interdisciplinary approaches in support of efforts to improve environmental health and landscape quality at polluted sites.

  4. Efficacy of resistance selection to Verticillium wilt in strawberry (Fragaria x ananassa Duch. tissue culture

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    Jadwiga I. Żebrowska

    2012-12-01

    Full Text Available The soil-borne pathogenic fungus Verticillium dahliae Kleb. causes economic losses in crops in temperate regions of the world and hence is the most studied species. Strawberry (Fragaria x ananassa Duch. belongs to plant species susceptible to Verticillium dahliae, although the response to infection caused by this pathogen is varied and depends on the cultivar. Due to a lack of efficient methods in Verticillium wilt elimination, the selection of genetically resistant plant material is a priority direction in breeding programs. Efficacy of resistance selection to Verticillium dahliae Kleb. in strawberry tissue culture was examined on the basis of response to in vitro infection by this pathogenic fungus in two tissue cultured strawberry cultivars, i.e. 'Filon' and 'Teresa'. Culture was conducted for 16 months in an environmentally controlled growth room at 18-20°C, 60-70% relative humidity and light intensity of 100 µm E × m-2 × s-1 on a 16h light / 8h dark cycle. Subcultures were proliferated every 6 weeks on modified Murashige and Skoog medium. Four hundred microplants from each tissue cultured cultivar were inoculated under in vitro conditions at the 4-leaf stage with a homogenate of liquid mycelium of Verticillium dahliae serving as the selecting agent. Disease symptoms were observed at 15, 30, 45, 60, and 75th days post inoculation. The extent of leaf chlorosis was rated on a scale of 0-4. At day 75th post inoculation, the percentage of totally chlorotic plants in micropropagated cv. Teresa reached the value of 76.27%, whereas the proportion of such plants in inoculated tissue cultured cv. Filon reached the value of 89.40%. Also, the index of infection calculated for very severe disease symptoms in the subclone 'Teresa' reached the mean value lower when compared with that calculated for subclone 'Filon' (0.0962 and 0.1150, respectively. These results suggested that the micropropagated cv. Teresa exhibited higher genetic resistance to the

  5. Lipophilic components of the brown seaweed, Ascophyllum nodosum, enhance freezing tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Rayirath, Prasanth; Benkel, Bernhard; Mark Hodges, D; Allan-Wojtas, Paula; Mackinnon, Shawna; Critchley, Alan T; Prithiviraj, Balakrishnan

    2009-06-01

    Extracts of the brown seaweed Ascophyllum nodosum enhance plant tolerance against environmental stresses such as drought, salinity, and frost. However, the molecular mechanisms underlying this improved stress tolerance and the nature of the bioactive compounds present in the seaweed extracts that elicits stress tolerance remain largely unknown. We investigated the effect of A. nodosum extracts and its organic sub-fractions on freezing tolerance of Arabidopsis thaliana. Ascophyllum nodosum extracts and its lipophilic fraction significantly increased tolerance to freezing temperatures in in vitro and in vivo assays. Untreated plants exhibited severe chlorosis, tissue damage, and failed to recover from freezing treatments while the extract-treated plants recovered from freezing temperature of -7.5 degrees C in in vitro and -5.5 degrees C in in vivo assays. Electrolyte leakage measurements revealed that the LT(50) value was lowered by 3 degrees C while cell viability staining demonstrated a 30-40% reduction in area of damaged tissue in extract treated plants as compared to water controls. Moreover, histological observations of leaf sections revealed that extracts have a significant effect on maintaining membrane integrity during freezing stress. Treated plants exhibited 70% less chlorophyll damage during freezing recovery as compared to the controls, and this correlated with reduced expression of the chlorphyllase genes AtCHL1 and AtCHL2. Further, the A. nodosum extract treatment modulated the expression of the cold response genes, COR15A, RD29A, and CBF3, resulting in enhanced tolerance to freezing temperatures. More than 2.6-fold increase in expression of RD29A, 1.8-fold increase of CBF3 and two-fold increase in the transcript level of COR15A was observed in plants treated with lipophilic fraction of A. nodosum at -2 degrees C. Taken together, the results suggest that chemical components in A. nodosum extracts protect membrane integrity and affect the expression of

  6. Complete Genome Sequence of Mulberry Vein Banding Associated Virus, a New Tospovirus Infecting Mulberry.

    Directory of Open Access Journals (Sweden)

    Jiaorong Meng

    Full Text Available Mulberry vein banding associated virus (MVBaV that infects mulberry plants with typical vein banding symptoms had been identified as a tentative species of the genus Tospovirus based on the homology of N gene sequence to those of tospoviruses. In this study, the complete sequence of the tripartite RNA genome of MVBaV was determined and analyzed. The L RNA has 8905 nucleotides (nt and encodes the putative RNA-dependent RNA polymerase (RdRp of 2877 aa amino acids (aa in the viral complementary (vc strand. The RdRp of MVBaV shares the highest aa sequence identity (85.9% with that of Watermelon silver mottle virus (WSMoV, and contains conserved motifs shared with those of the species of the genus Tospovirus. The M RNA contains 4731 nt and codes in ambisense arrangement for the NSm protein of 309 aa in the sense strand and the Gn/Gc glycoprotein precursor (GP of 1,124 aa in the vc strand. The NSm and GP of MVBaV share the highest aa sequence identities with those of Capsicum chlorosis virus (CaCV and Groundnut bud necrosis virus (GBNV (83.2% and 84.3%, respectively. The S RNA is 3294 nt in length and contains two open reading frames (ORFs in an ambisense coding strategy, encoding a 439-aa non-structural protein (NSs and the 277-aa nucleocapsid protein (N, respectively. The NSs and N also share the highest aa sequence identity (71.1% and 74.4%, respectively with those of CaCV. Phylogenetic analysis of the RdRp, NSm, GP, NSs, and N proteins showed that MVBaV is most closely related to CaCV and GBNV and that these proteins cluster with those of the WSMoV serogroup, and that MVBaV seems to be a species bridging the two subgroups within the WSMoV serogroup of tospoviruses in evolutionary aspect, suggesting that MVBaV represents a distinct tospovirus. Analysis of S RNA sequence uncovered the highly conserved 5'-/3'-ends and the coding regions, and the variable region of IGR with divergent patterns among MVBaV isolates.

  7. Iron and ferritin accumulate in separate cellular locations in Phaseolus seeds

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    Blair Matthew W

    2010-02-01

    Full Text Available Abstract Background Iron is an important micronutrient for all living organisms. Almost 25% of the world population is affected by iron deficiency, a leading cause of anemia. In plants, iron deficiency leads to chlorosis and reduced yield. Both animals and plants may suffer from iron deficiency when their diet or environment lacks bioavailable iron. A sustainable way to reduce iron malnutrition in humans is to develop staple crops with increased content of bioavailable iron. Knowledge of where and how iron accumulates in seeds of crop plants will increase the understanding of plant iron metabolism and will assist in the production of staples with increased bioavailable iron. Results Here we reveal the distribution of iron in seeds of three Phaseolus species including thirteen genotypes of P. vulgaris, P. coccineus, and P. lunatus. We showed that high concentrations of iron accumulate in cells surrounding the provascular tissue of P. vulgaris and P. coccineus seeds. Using the Perls' Prussian blue method, we were able to detect iron in the cytoplasm of epidermal cells, cells near the epidermis, and cells surrounding the provascular tissue. In contrast, the protein ferritin that has been suggested as the major iron storage protein in legumes was only detected in the amyloplasts of the seed embryo. Using the non-destructive micro-PIXE (Particle Induced X-ray Emission technique we show that the tissue in the proximity of the provascular bundles holds up to 500 μg g-1 of iron, depending on the genotype. In contrast to P. vulgaris and P. coccineus, we did not observe iron accumulation in the cells surrounding the provascular tissues of P. lunatus cotyledons. A novel iron-rich genotype, NUA35, with a high concentration of iron both in the seed coat and cotyledons was bred from a cross between an Andean and a Mesoamerican genotype. Conclusions The presented results emphasize the importance of complementing research in model organisms with analysis in

  8. Effects of Different Ratio of Wood Vinegar Fertilizer on Camphor Forest Soil%不同配比的木醋肥对香樟林土壤性状的影响

    Institute of Scientific and Technical Information of China (English)

    胡妍玢; 陈杰; 杨学军; 李辉信

    2013-01-01

    将不同配比的木醋肥施用于香樟林地中,通过测定施肥后林地土壤微生物数量、酶活性、土壤部分化学性质以及植物黄化相关指标的变化情况,旨在选择效果明显的配比应用于城市绿地绿化植物的养护中.试验结果表明,6种试验配方均能不同程度地改善香樟林土壤性状,主要表现在:微生物数量增加、酶活性提高、化学性质得到改良,同时香樟黄化也得到有效控制.低浓度木醋液中加入低量有机肥,对土壤微生物有一定的抑制作用,并且化学性质和黄化改良效果不如其他处理明显;从生产应用、使用价值等综合效果来看,中低浓度木醋液中加入木炭粉(木醋液∶木炭粉比例为1∶5(V∶M))和中高量有机肥的处理改良效果最好.%By using different ratios of wood vinegar fertilizer in camphor forest,the changes of relevant indexes of soil microbial number,chemical properties,soil enzyme activity and chlorosis index was studied.The results showed that all the six different ratios of wood vinegar fertilizer could improve chemical properties of soil,increase soil microbial quantity,enhance soil enzyme activity and control etiolation of camphora trees.Compared with contrast,the ratio with low concentration of wood vinegar and low organic fertilizer treatment was not as good as other treatments in inhibiting soil microorganism,improving chemical properties and controlling etiolation.Based on an overall consideration of various factors,the ratios with middle or low concentration of wood vinegar added charcoal powder (wood vinegar:charcoal powder ratio =1 ∶ 5 (V / M) and middle or high organic fertilizer were better in use of urban afforesting and greening.

  9. Development and characterization of an oat TILLING-population and identification of mutations in lignin and β-glucan biosynthesis genes

    Directory of Open Access Journals (Sweden)

    Vivekanand Vivekanand

    2010-05-01

    Full Text Available Abstract Background Oat, Avena sativa is the sixth most important cereal in the world. Presently oat is mostly used as feed for animals. However, oat also has special properties that make it beneficial for human consumption and has seen a growing importance as a food crop in recent decades. Increased demand for novel oat products has also put pressure on oat breeders to produce new oat varieties with specific properties such as increased or improved β-glucan-, antioxidant- and omega-3 fatty acid levels, as well as modified starch and protein content. To facilitate this development we have produced a TILLING (Targeting Induced Local Lesions IN Genomes population of the spring oat cultivar SW Belinda. Results Here a population of 2600 mutagenised M2 lines, producing 2550 M3 seed lots were obtained. The M2 population was initially evaluated by visual inspection and a number of different phenotypes were seen ranging from dwarfs to giants, early flowering to late flowering, leaf morphology and chlorosis. Phloroglucinol/HCl staining of M3 seeds, obtained from 1824 different M2 lines, revealed a number of potential lignin mutants. These were later confirmed by quantitative analysis. Genomic DNA was prepared from the M2 population and the mutation frequency was determined. The estimated mutation frequency was one mutation per 20 kb by RAPD-PCR fingerprinting, one mutation per 38 kb by MALDI-TOF analysis and one mutation per 22.4 kb by DNA sequencing. Thus, the overall mutation frequency in the population is estimated to be one mutation per 20-40 kb, depending on if the method used addressed the whole genome or specific genes. During the investigation, 6 different mutations in the phenylalanine ammonia-lyase (AsPAL1 gene and 10 different mutations in the cellulose synthase-like (AsCslF6 β-glucan biosynthesis gene were identified. Conclusion The oat TILLING population produced in this work carries, on average, hundreds of mutations in every individual

  10. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour.

    Science.gov (United States)

    Fereres, Alberto; Peñaflor, Maria Fernanda G V; Favaro, Carla F; Azevedo, Kamila E X; Landi, Carolina H; Maluta, Nathalie K P; Bento, José Mauricio S; Lopes, Joao R S

    2016-01-01

    Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However

  11. Comportamento do girassol em relação a acidez do solo Sunflower response to soil acidity conditions

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    Maria Regina Gonçalves Ungaro

    1985-01-01

    Full Text Available Em solo Podzólico Vermelho-Amarelo, foi instalado, no ano agrícola de 1981/82, um ensaio de rotação de culturas envolvendo milho, soja, mucuna-preta e girassol. Doze parcelas foram plantadas com girassol: algumas apresentaram germinação baixa, parte aérea pouco desenvolvida e com clorose generalizada nas folhas; sistema radicular com raiz pivotante encurvada e ramificações secundárias pouco abundantes e grossas. As produções variaram conforme a intensidade desses sintomas. Com os resultados da análise de solo de cada parcela, obtiveram-se relações lineares entre produção de grãos de girassol e pH (r = 0,95 e saturação em bases do solo (r = 0,92. Obtiveram-se ainda outras relações, também lineares, entre altura de plantas, diâmetro dos capítulos e os índices de acidez do solo. Os resultados mostraram que o girassol também foi sensível à acidez do solo e que o critério do alumínio trocável, para a recomendação de calagem, não foi o mais adequado para esta planta.A crop rotation experiment involving corn, soybean, sunflower, and green manure was carried out in a Red-Yellow Podzolic soil. In some of the 12 plots with sunflower the seed germination was poor and the plants showed reduced growth, with leaf chlorosis, curved main roots, and fewer and thicker secondary roots. Yield was negatively correlated with the intensity of these symptoms. The grain yield was highly correlated with soil pH (r = 0.95 and soil base saturation (r = 0.92. Plant height and head diameter also showed linear relationship with those soil indices. The results obtained show that sunflower is very sensitive to soil acidity, and that the exchangeable aluminum criterion is inadequate for determining lime requirement for sunflower.

  12. Teores de nutrientes em cultivares de café arábica submetidos à deriva de glyphosate Nutrient content in arabica coffee cultivars subjected to glyphosate drift

    Directory of Open Access Journals (Sweden)

    A.C França

    2010-12-01

    Full Text Available Avaliaram-se, neste trabalho, os efeitos do glyphosate sobre os teores foliares de nutrientes em três cultivares de café (Coffea arabica. Utilizou-se o esquema fatorial (3 x 5 em delineamento de blocos casualizados, com quatro repetições, sendo os tratamentos compostos por três cultivares de café: Catucaí Amarelo (2 SL, Oeiras (MG-6851 e Topázio (MG-1190; e cinco doses de glyphosate (0; 57,6; 115,2; 230,4; e 460,8 g ha-1. Aos 45 e 120 DAA, coletaram-se folhas (terceiro par de ramos plagiotrópicos, contidos na parte mediana das plantas. Os sintomas de intoxicação foram caracterizados por clorose e estreitamento do limbo foliar para os três cultivares de café. Houve redução nos teores foliares de N, P, K, Cu e Zn aos 45 DAA e de N, K, Mn e Zn aos 120 DAA nas plantas de café tratadas com glyphosate, independentemente do cultivar utilizado. O cultivar Topázio apresentou as maiores reduções nos teores foliares de Fe e Mn, aos 45 DAA, e de P e Fe, aos 120 DAA.The effects of glyphosate on the foliar levels of nutrients in three coffee cultivars (Coffea arabica were evaluated in this work. A factorial (3 x 5 was used in a randomized block design with four replications, with treatments consisting of three coffee varieties: Catucaí Amarelo (2 SL, Oeiras (MG-6851 and Topázio (MG-1190 and five glyphosate doses (0, 57.6, 115.2, 230.4 and 460.8 g ha-1. At 45 and 120 DAA, leaves (third pair from plagiotrophic branches were collected from the medium part of the plants. Glyphosate intoxication symptoms were characterized by chlorosis and leaf narrowing for the three coffee varieties. There was a reduction in foliar levels of N, P, K, Cu and Zn at 45 DAA, and N, K, Mn and Zn at 120 DAA, in coffee plants treated with glyphosate, regardless of the cultivar used. Cultivar Topázio showed the greatest reductions in the foliar levels of Fe and Mn, at 45 DAA and P and Fe, at 120 DAA, when treated with glyphosate.

  13. Produção de prolina e suscetibilidade ao glufosinato de amônio em plantas transgênicas de citrumelo Swingle Proline production by transgenic plants of Swingle citrumelo and susceptibility to glufosinate ammonium

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    Cristine Elizabeth Alvarenga Carneiro

    2006-05-01

    Full Text Available O objetivo deste trabalho foi avaliar a sensibilidade de plantas transgênicas de citrumelo Swingle com elevada produção de prolina, ao herbicida glufosinato de amônio. As plantas utilizadas apresentavam a inserção do gene mutante da enzima delta1-pirrolina-5-carboxilato sintetase (P5CS, responsável pela biossíntese de prolina. A expressão do gene p5cs em plantas transgênicas causou aumento nas quantidades de prolina em tecidos foliares, em até cinco vezes, quando comparadas às plantas-controle tratadas com 200 µM de glufosinato de amônio. As plantas transgênicas acumularam maior quantidade de NH4+ nas folhas, em relação às plantas não-transgênicas. Os danos causados pelo herbicida foram avaliados in vitro, utilizando-se discos foliares cultivados em meio MS com diferentes concentrações de glufosinato de amônio. Observou-se maior clorose em discos foliares das plantas transgênicas, o que comprova a maior suscetibilidade de plantas de citrumelo Swingle com alta produção de prolina ao herbicida.The objective of this work was to evaluate the susceptibility to glufosinate ammonium of transgenic plants of Swingle citrumelo with high proline production. The mutant gene of the enzyme delta1-pyrroline-5-carboxylate synthetase (P5CS, the rate-limiting enzyme in proline biosynthesis, was inserted into Swingle citrumelo plants. The expression of the gene p5cs caused up to 5-fold increase on the proline content in leaf tissues of transgenic plants treated with 200 µM glufosinate ammonium, when compared with control plants. Leaves of transgenic plants accumulated higher amounts of NH4+ than the nontransgenic control. The herbicide toxicity was evaluated using leaf disks cultivated in MS medium, containing different concentrations of glufosinate ammonium. The severity of the chlorosis, observed in leaf disks of transgenic plants, confirmed the higher susceptibility of Swingle citrumelo plants, with high proline production, to this

  14. Genetic characterization of Xylella fastidiosa isolated from citrus and coffee plants Caracterização genética de Xylella fastidiosa isolada de plantas de citros e café

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    Vicente Savonitti Miranda

    2007-10-01

    Full Text Available The Citrus Variegated Chlorosis and the Coffee Leaf Scorch are some of the many destructive diseases caused by Xylella fastidiosa, a gram-negative bacterium limited to the xylem of affected plants. As its genetic characterization is still not well established, different isolates of X. fastidiosa from citrus and coffee were evaluated through RAPD (Random Amplified Polymorphic DNA technique to characterize and classify these isolates based on similarity coefficients. Sixteen isolates of X. fastidiosa were used on this trial, obtained from citrus, coffee and almond. The genetic polymorphism evaluation was performed using six arbitrary 10-base primer pairs. It was possible to establish a dendogram in which the isolates were classified into five groups (A, B, C, D and E. A prevalence of citrus isolates in groups A and D was observed. In groups B and C, there was a prevalence of coffee isolates meanwhile the group D consisted of the almond isolate, solely.A Clorose Variegada dos Citros e a Requeima das Folhas do Cafeeiro são algumas das várias doenças destrutivas causadas pela Xylella fastidiosa, que é uma bactéria gram-negativa e limitada ao xilema de plantas afetadas. Como a sua caracterização genética ainda não está determinada, diferentes isolados da X. fastidiosa de citros e café foram avaliados pela técnica RAPD (Polimorfismo do DNA Amplificado ao Acaso para caracterizar e classificar estes isolados com base em coeficientes de similaridade. Foram utilizados 16 isolados de X. fastidiosa provenientes de citros, café e amêndoa. A avaliação do polimorfismo genético foi realizada utilizando seis iniciadores randômicos de 10 pares de base. Foi possível estabelecer um dendograma no qual os isolados foram classificados em cinco grupos (A, B, C, D e E. Nos grupos A e D existe uma forte predominância de isolados de citros. Nos grupos B e C há predominância de isolados de café enquanto no grupo E ficou apenas o isolado de amêndoa.

  15. Redução dos sintomas causados pela Xylella fastidiosa subsp. pauca por meio de aplicação de benzotiadiazole e silício Redution of the symptons caused by Xylella fastidiosa subsp. pauca through application of benzothiadiazole and silicon

    Directory of Open Access Journals (Sweden)

    Juliana Camargo Martinati

    2007-08-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da aplicação do benzotiadiazole (BTH e do silício sobre o controle da doença causada pela Xylella fastidiosa subsp. pauca em Nicotiana tabacum. Os experimentos foram conduzidos em condições de casa de vegetação, onde as plantas de N. tabacum receberam inoculação de X. fastidiosa (linhagem 9a5c com 4,7x10(7 UFC mL-1. Os tratamentos consistiram da pulverização das folhas, com soluções de BTH (0,6 e 1,2 mM, e aplicação ao solo de soluções de metassilicato de sódio (2 e 4 µM de Si. Cinco plantas foram utilizadas, por tratamento. Plantas de N. tabacum tratadas com BTH não demonstraram redução de sintomas da bacteriose. Entretanto, plantas tratadas com metassilicato de sódio, sim. A indução de resistência pelo Si poderá ser útil no controle da clorose variegada dos citros.The objective of this work was to evaluate the effects of benzothiadiazole (BTH and silicon applications on the control of the disease caused by Xylella fastidiosa subsp. pauca on Nicotiana tabacum. The experiments were carried out under greenhouse conditions, where X. fastidiosa (9a5c strain containing 4.7x10(7 CFU mL-1 was inoculated in N. tabacum plants. The BTH and silicon treatments consisted of BTH (0.6 and 1.2 mM application to plant leaves, and sodium metasilicate solution (2 and 4 µM of Si application to soil. Plants of N. tabacum treated with BTH showed no reduction in symptoms. However, plants treated with sodium metasilicate (source of Si were rendered asymptomatic. Disease resistance induced by Si can be useful to control citrus variegated chlorosis.

  16. Incidência de Dilobopterus costalimai Young e Acrogonia citrina Marucci & Cavichioli, em pomares cítricos no noroeste paranaense = Incidence of Dilobopterus costalimai Young and Acrogonia citrina Marucci & Cavichioli, in citrus orchards in Northwestern Paraná

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    Aline Maria Orbolato Gonçalves

    2008-07-01

    Full Text Available As cigarrinhas das famílias Cicadellidae e Cercopidae são vetores da bactéria Xylella fastidiosa Wells, causadora da Clorose variegada dos citros. Esta doença traz sérios prejuízos à lavoura de citros no Noroeste Paranaense, e é estudada no Brasil desde 1987, quando foi descoberta pela primeira vez na região de Colina, São Paulo. Os vetores transmitem a X. fastidiosa quando se alimentam sugando a seiva do xilema, local onde a bactéria se instala, obstruindo a passagem da seiva. Este trabalho teve o objetivo de avaliar aocorrência das cigarrinhas vetoras Dilobopterus costalimai e Acrogonia citrina em pomar comercial de citros. O experimento foi realizado no sítio “Laranjeiras I”, município de Nova Esperança, região noroeste do Paraná, no período de julho de 2004 a agosto de 2006. Foram feitas amostragens mensais, por meio de armadilhas adesivas amarelas (Biocontrole®, nas variedades de laranjeiras [Citrus sinensis (L. Osbeck] Folha Murcha, Valência, Pêra e Natal.Nas variedades Pêra e Valência, a cigarrinha mais capturada foi Dilobopterus costalimai. Os meses de maior ocorrência das espécies foram entre dezembro e maio de cada ano.The sharpshooters of the families Cicadellidae and Cercopidae are vectors of Xylella fastidiosa (Wells, which causes citrus variegated chlorosis. This disease causes severe damage to the Paraná citrus industry, and it has been studied in Brazil since 1987, when it was discovered for the first time in the area of Colina, SP. The vectors transmit X. fastidiosa when they feed on the xylem sap, where the bacteria settles, obstructing the passage of the sap. This workhad the objective of evaluating the occurrence of the vector sharpshooter Dilobopterus costalimai and Acrogonia citrina in a commercial citrus orchard during the period between July 2004 and August 2006. The experiment was accomplished in the Laranjeiras I farm, in the city of Nova Esperança, northwestern Paraná. The collections

  17. Bioassay assessment of metarhizium anisopliae (metchnikoff sorokin (deuteromycota: hyphomycetes against Oncometopia facialis (signoret (hemiptera: cicadellidae Avaliação do bioensaio de Metarhizium anisopliae (metchnikoff sorokin (deuteromycota: hyphomycetes contra Oncometopia facialis (signoret (hemiptera: cicadellidae

    Directory of Open Access Journals (Sweden)

    Wolney Dalla Pria Júnior

    2008-03-01

    Full Text Available Citrus Variegated Chlorosis (CVC is an economically important, destructive disease in Brazil and is caused by Xylella fastidiosa and transmitted by sharpshooter insects. In this study, the efficacy of the fungus Metarhizium anisopliae in controlling the sharpshooter Oncometopia facialis was studied by bioassay conditions. In the bioassay, insects were sprayed with a suspension containing 5 X 10(7 conidia mL-1. Adults captured in the field were treated in groups of 10 in a total of 11 replications per treatment. Significant differences between the natural mortality and the mortality of insects treated with the fungus were observed 6 days after inoculations (PA Clorose Variegada dos Citros (CVC é uma doença economicamente importante e destrutiva no Brasil e é causada pela bactéria Xylella fastidiosa e transmitida por insetos vetores tal como Oncometopia facialis. Nesse estudo, a eficácia do fungo Metarhizium anisopliae em controlar o inseto vetor O. facialis foi estudada em condições de bioensaio. Nesse bioensaio, insetos foram pulverizados com uma suspensão de 5 X 10(7 conídio mL-1. Insetos-adultos capturados no campo foram tratados em grupos de 10, em um total de 11 replicatas por tratamento. Diferenças significativas entre a mortalidade natural e a mortalidade dos insetos tratados com o fungo foram observadas em 6 dias após a inoculação (P<0.05. Estas diferenças significativas aumentaram antes do décimo dia após o tratamento. O fungo causou uma mortalidade de 87,1%, com uma LT50 variando entre 5 e 6 dias. A LC50 foi de 1,2 X 10(6 conídio mL-1, variando de 7,7 X 10(5 a 2 X 10(6 conídio mL-1. Estes resultados mostraram que o vetor O. facialis foi susceptível a ação entomopatogênica de M. anisopliae em condições controladas durante o bioensaio.

  18. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour

    Science.gov (United States)

    Fereres, Alberto; Peñaflor, Maria Fernanda G. V.; Favaro, Carla F.; Azevedo, Kamila E. X.; Landi, Carolina H.; Maluta, Nathalie K. P.; Bento, José Mauricio S.; Lopes, Joao R.S.

    2016-01-01

    Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However

  19. Incidencia y sintomatología de cinco virus en parcelas comerciales de chile seco en Aguascalientes, San Luis Potosí y Zacatecas, México Incidence and symptomatology of five viruses in commercial dry chili pepper fields in Aguascalientes, San Luis Potosí, and Zacatecas, Mexico

    Directory of Open Access Journals (Sweden)

    Rodolfo Velásquez-Valle

    2012-04-01

    Full Text Available A nivel mundial el cultivo de chile es afectado por más de 60 enfermedades virales; sin embargo, poco se conoce acerca de ellas en el área productora de chile seco del norte centro de México por lo que el objetivo del presente trabajo consistió en detectar la presencia y sintomatología de cinco virus en parcelas comerciales de chile seco en los estados mencionados. Plantas de chile de los tipos mirasol y ancho fueron muestreadas y se anotó la presencia de síntomas como enanismo, clorosis, deformación de hojas, defoliación, necrosis vascular y ramas unidas. Las muestras fueron analizadas mediante la técnica DAS-ELISA empleando los antisueros para el virus del mosaico del tabaco (Tobacco mosaic virus: TMV, mosaico del pepino (Cucumber mosaic virus: CMV, Y de la papa (Potato virus Y: PVY, moteado del chile (Pepper mottle virus: PepMoV y jaspeado del tabaco (Tobacco etch virus: TEV. Esos virus fueron identificados en plantas de chile colectadas en las parcelas comerciales de chile seco de los tres estados antes mencionados.World-wide the chili pepper crop is affected by more than 60 viral diseases, although very little is known about them in the area of dry pepper plantation in northern-central Mexico. Consequently, the aims of this work were to identify the presence of the virus and the associated symptoms in commercial dry pepper fields of the states of Zacatecas, San Luis Potosí, and Aguascalientes, Mexico. Mirasol and ancho pepper plants were sampled and the presence of symptoms such as dwarfing, chlorosis, leaf deformation, defoliation, vascular necrosis and joined branches, were recorded. Samples were analyzed using DAS-ELISA with the antisera of the tobacco mosaic virus (Tobacco mosaic virus: TMV, cucumber mosaic virus (Cucumber mosaic virus: CMV, potato virus Y (Potato virus Y: PVY, pepper mottle virus (Pepper mottle virus: PepMoV, and tobacco etch virus (Tobacco etch virus: TEV. These viruses were identified in pepper plants

  20. Phytoavailability of Arsenic in pesticide-Applied Soils: Effect of Chemical Remediation

    Science.gov (United States)

    Mohamed, H.; Therapong, C.; Andra, S.; Datta, R.; Sarkar, D.

    2005-05-01

    Arsenic (As) occurs naturally in rocks and soils and in the water in contact with them. Arsenic contamination is also caused by a variety of anthropogenic activities such as the use of arsenical pesticides, mining, and other industrial processes. In humans, chronic exposure to As has been found to cause a number of cancers, peripheral nerve damage, and skin hyper-pigmentation. In plants, As causes growth inhibition, chlorosis, defoliation, and water-deficiency stress. The main objective of the present study was to evaluate the efficacy of water treatment residuals (WTRs) in reducing the phytoavailability of As in soils. WTRs are the by-products from drinking water purification plants and contain sediments, organic material from the raw water, Al/Fe oxides and activated C. They are amorphous and have an affinity for oxyanions (e.g., arsenate and arsenite), due to the high positive surface charge they generally possess. A greenhouse study was performed using two different types of soils, chosen on the basis of their potential differences with respect to reactivity and phytoavailability of As: Immokalee series (bleached sand with low pH) and Orelia series (sandy loam with high percentage of Ca; Mg and high pH). Rice (Oryza sativa var. M202) was used as the test crop to study the effect of WTR amendment on the plant availability of As. The soils were amended with two arsenical pesticides; sodium arsenate and dimethylarsenic acid (DMA) at two rates: 675 and 1500 mg/kg of As, representing the high end of As contamination, simulating Superfund site conditions. Rice plants were grown with and without WTRs for a period of 6 months. Growth parameters (germination percentage, plant biomass, root and shoot length) as well as As accumulation in plant tissues were studied. Soils were analyzed to determine the levels of plant available As in WTR-treated and untreated soils. Results obtained indicate that WTR-amendment of sodium arsenate contaminated soils resulted in considerable

  1. Ozone and carbon dioxide effects on spider mites in white clover and peanut

    Energy Technology Data Exchange (ETDEWEB)

    Heagle, A.S.; Brandenburg, R.L.; Burns, J.C.; Miller, J.E. [North Carolina State Univ., Raleigh, NC (United States)

    1994-11-01

    Effects of O{sub 3} and/or elevated CO{sub 2} on two-spotted spider mites (Tetranychus urticae Koch) grown on an O{sub 3}-sensitive and an O{sub 3}-resistant clone of white clover (Trifolium repens L.) were measured in greenhouse and field experiments. Peanut (Arachis hypogeae L.) {open_quote}NC-9{close_quote} was used in one greenhouse study with O{sub 3}. In field studies, O{sub 3} treatments were charcoal filtered air (CF), nonfiltered air (NF), and two NF treatments with O{sub 3} added for 12 h d{sup {minus}1} at proportions of {approx} 1.25 and 1.50 times the ambient O{sub 3} concentration. In greenhouse studies, constant amounts of O{sub 3} were added to CF for 6 h d{sup {minus}1} to achieve mean concentrations ranging from 5 to 100 nL L{sup {minus}1}. For the greenhouse O{sub 3} x CO{sub 2} experiment, CO{sub 2} concentrations were ambient and approximately twice-ambient for 24 h d{sup {minus}1}. Plants were exposed to O{sub 3} and/or CO{sub 2} for {approx} 7 d before infestation with mites; daily exposures continued for 14 to 28 d to allow reproduction for at least two generations. Leaves were sampled to count eggs, larvae, nymphs, and adults. Ozone caused more chlorosis and necrosis on the O{sub 3}-sensitive clover clone (NC-S) than on the O{sub 3}-resistant clone (NC-R). Carbon dioxide enrichment increased shoot growth of both clones by {approx}33%. Statistical analyses indicated significant O{sub 3} effects in some experiments and nonsignificant O{sub 3} effects in others. A trend toward increased mite populations with increased O{sub 3} occurred, however, on NC-S in all trials. No consistent trends occurred with NC-R. With peanut, a significant linear increase in mite population occurred with increased O{sub 3}. Carbon dioxide enrichment increased the rate of population increase on both clover clones, but more so on NC-R. 47 refs., 2 figs., 7 tabs.

  2. Evaluación del riesgo ambiental de carbofurano en bioensayos con organismos no blanco

    Directory of Open Access Journals (Sweden)

    José Alberto Iannacone

    2011-06-01

    Full Text Available El carbofurano es uno de los plaguicidas más empleado en la agricultura peruana. El objetivo de este trabajo fue evaluar el riesgo ambiental del carbofurano en bioensayos de toxicidad, sobre once especies no destinatarias. La siguiente secuencia relativa de mayor a menor cocientes de riesgo (CR del carbofurano para los 19 puntos finales de efecto en once especies fue encontrada: Daphnia magna (mortalidad > Lemna minor (inhibición de formación de las hojas > Paracheirodon innesi (nado extraño = P. innesi (incremento del movimiento opercular > Chironomus calligraphus (mortalidad > L. minor (necrosis > P. innesi (mortalidad > L. minor (clorosis > Tetrapygus niger (inhibición de la fecundación > Coturnix japonica (mortalidad > Oncorhynchus mykiss (incremento de coloración > Ceraeochrysa cincta (no eclosión de huevos > O. mykiss (mortalidad con oxígeno > O. mykiss (mortalidad sin oxígeno > Trichogramma pretiosum (mortalidad > C. cincta (mortalidad > T. pretiosum (no emergencia de adultos > Trichogramma pintoi (mortalidad > Beauveria bassiana (inhibición del crecimiento. Los cocientes de riesgo (CR indicaron en todos los casos un alto riesgo del carbofurano principalmente en el ambiente acuático en comparación con el terrestre.Carbofuran is one of the most employed pesticides in Peruvian agriculture. This research aimed to evaluate the risk assessment in bioassays of carbofuran on eleven non-target species. The following relative sequence in decreasing ecotoxicity order in terms of RQ (Risk quotient to carbofuran to 19 end points on 11 species was found: Daphnia magna (mortality > Lemna minor (inhibition of new fronds > Paracheirodon innesi (strange swim = P. innesi (increase of opercula movement > Chironomus calligraphus (mortality > L. minor (necrosis > P. innesi (mortality > L. minor (chlorosis > Tetrapygus niger (inhibition of fertilization> Coturnix japonica (mortality > Oncorhynchus mykiss (increase of coloration > Ceraeochrysa

  3. Multifactorial biogeochemical monitoring of linden alley in Moscow

    Science.gov (United States)

    Ermakov, Vadim; Khushvakhtova, Sabsbakhor; Tyutikov, Sergey; Danilova, Valentina; Roca, Núria; Bech, Jaume

    2015-04-01

    The ecological and biogeochemical assessment of the linden alley within the Kosygin Street was conducted by means of an integrated comparative study of soils, their chemical composition and morphological parameters of leaf linden. For this purpose 5 points were tested within the linden alley and 5 other points outside the highway. In soils, water extract of soil, leaf linden the content of Cu, Pb, Mn, Fe, Cd, Zn, As, Ni, Co Mo, Cr and Se were determined by AAS and spectrofluorimetric method [1]. Macrocomponents (Ca, Mg, K, Na, P, sulphates, chlorides), pH and total mineralization of water soil extract were measured by generally accepted methods. Thio-containing compounds in the leaves were determined by HPLC-NAM spectrofluorometry [2]. On level content of trace elements the soils of "contaminated" points different from background more high concentrations of lead, manganese, iron, selenium, strontium and low level of zinc. Leaf of linden from contaminated sites characterized by an increase of lead, copper, iron, zinc, arsenic, chromium, and a sharp decrease in the level of manganese and strontium. Analysis of the aqueous extracts of the soil showed a slight decrease in the pH value in the "control" points and lower content of calcium, magnesium, potassium, sodium and total mineralization of the water soil extract. The phytochelatins test in the leaves of linden was weakly effective and the degree of asymmetry of leaf lamina too. The most differences between the variants were marked by the degree of pathology leaves (chlorosis and necrosis) and the content of pigments (chlorophyll and carotene). The data obtained reflect the impact of the application of de-icing salts and automobile emissions. References 1. Ermakov V.V., Danilova V.N., Khyshvakhtova S.D. Application of HPLC-NAM spectrofluorimtry to determination of sulfur-containing compounds in the environmental objects// Science of the biosphere: Innovation. Moscow State University by M.V. Lomonosov, 2014. P. 10

  4. Effects of CO2 Concentration on Leaf Photosynthesis and Stomatal Conductance of Potatoes Grown Under Different Irradiance Levels and Photoperiods

    Science.gov (United States)

    Wheeler, R. M.; Fitzpatrick, A. H.; Tibbitts, T. W.

    2012-01-01

    Potato (Solanum tuberosum L.) cvs. Russet Burbank, Denali, and Norland, were grown in environmental rooms controlled at approx 350 micro mol/mol (ambient during years 1987/1988) and 1000 micro mol/mol (enriched) CO2 concentrations. Plants and electric lamps were arranged to provide two irradiance zones, 400 and 800 micro mol/mol/square m/S PPF and studies were repeated using two photoperiods (12-h light / 12-h dark and continuous light). Leaf photosynthetic rates and leaf stomatal conductance were measured using fully expanded, upper canopy leaves at weekly intervals throughout growth (21 through 84 days after transplanting). Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod increased leaf photosynthetic rates by 39% at 400 micro mol/mol/square m/S PPF and 27% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under continuous light decreased leaf photosynthetic rates by 7% at 400 micro mol/mol/square m/S PPF and 13% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod plants decreased stomatal conductance by an average of 26% at 400 micro mol/mol/square m/S PPF and 42% at 800 micro mol/mol/square m/S PPF. Under continuous light, CO2 enrichment resulted in a small increase (2%) of stomatal conductance at 400 micro mol/mol/square m/S PPF, and a small decrease (3%) at 800 micro mol/mol/square m/S PPF. Results indicate that CO2 enrichment under the 12-h photoperiod showed the expected increase in photosynthesis and decrease in stomatal conductance for a C3 species like potato, but the decreases in leaf photosynthetic rates and minimal effect on conductance from CO2 enrichment under continuous light were not expected. The plant leaves under continuous light showed more chlorosis and some rusty flecking versus plants under the 12-h photoperiod, suggesting the continuous light was more stressful on the plants. The increased

  5. Comparative genomic characterization of citrus-associated Xylella fastidiosa strains

    Directory of Open Access Journals (Sweden)

    Nunes Luiz R

    2007-12-01

    Full Text Available Abstract Background The xylem-inhabiting bacterium Xylella fastidiosa (Xf is the causal agent of Pierce's disease (PD in vineyards and citrus variegated chlorosis (CVC in orange trees. Both of these economically-devastating diseases are caused by distinct strains of this complex group of microorganisms, which has motivated researchers to conduct extensive genomic sequencing projects with Xf strains. This sequence information, along with other molecular tools, have been used to estimate the evolutionary history of the group and provide clues to understand the capacity of Xf to infect different hosts, causing a variety of symptoms. Nonetheless, although significant amounts of information have been generated from Xf strains, a large proportion of these efforts has concentrated on the study of North American strains, limiting our understanding about the genomic composition of South American strains – which is particularly important for CVC-associated strains. Results This paper describes the first genome-wide comparison among South American Xf strains, involving 6 distinct citrus-associated bacteria. Comparative analyses performed through a microarray-based approach allowed identification and characterization of large mobile genetic elements that seem to be exclusive to South American strains. Moreover, a large-scale sequencing effort, based on Suppressive Subtraction Hybridization (SSH, identified 290 new ORFs, distributed in 135 Groups of Orthologous Elements, throughout the genomes of these bacteria. Conclusion Results from microarray-based comparisons provide further evidence concerning activity of horizontally transferred elements, reinforcing their importance as major mediators in the evolution of Xf. Moreover, the microarray-based genomic profiles showed similarity between Xf strains 9a5c and Fb7, which is unexpected, given the geographical and chronological differences associated with the isolation of these microorganisms. The newly

  6. A New Disease of Cherry Plum Tree with Yellow Leaf Symptoms Associated with a Novel Phytoplasma in the Aster Yellows Group

    Institute of Scientific and Technical Information of China (English)

    LI Zheng-nan; ZHANG Lei; TAO Ye; CHI Ming; XIANG Yu; WU Yun-feng

    2014-01-01

    A novel phytoplasma was detected in a cherry plum (Prunus cerasifera Ehrh) tree that mainly showed yellow leaf symptom. The tree was growing in an orchard located in Yangling District, Shaanxi Province, China. The leaves started as chlorotic and yellowing along leaf minor veins and leaf tips. Chlorosis rapidly developed to inter-veinal areas with the whole leaf becoming pale yellow in about 1-4 wk. Large numbers of phytoplasma-like bodies (PLBs) were seen under transmission electron microscopy. The majority of the PLBs was spherical or elliptical vesicles, with diameters in range of 0.1-0.6 µm, and distributed in the phloem cells of the infected tissues. A 1 246-bp 16S ribosomal RNA (rRNA) gene fragment was ampliifed from DNA samples extracted from the yellow leaf tissues using two phytoplasma universal primer pairs R16mF2/R16mR1 and R16F2n/R16R2. Phylogenetic analysis using the 16S rRNA gene sequence suggested that the phytoplasma associated with the yellow leaf symptoms belongs to a novel subclade in the aster yellows (AY) group (16SrI group). Virtual and actual restriction fragment length polymorphism (RFLP) analysis of the 16S rRNA gene fragment revealed that the phytoplasma was distinguishable from all existing 19 subgroups in the AY group (16SrI) by four restriction sites, Hinf I, Mse I, Sau3A I and Taq I. The similarity coefifcients of comparing the RFLP pattern of the 16S rRNA gene fragment of this phytoplasma to each of the 19 reported subgroups ranged from 0.73 to 0.87, which indicates the phytoplasma associated with the cherry plum yellow leaf (CPYL) symptoms is probably a distinct and novel subgroup lineage in the AY group (16SrI). In addition, the novel phytoplasma was experimentally transmitted to periwinkle (Catharanthus roseus) plants from the tree with CPYL symptoms and then back to a healthy 1-yr-old cherry plum tree via dodder (Cuscuta odorata) connections.

  7. Comparison of phenotypes produced in response to transient expression of genes encoded by four distinct begomoviruses in Nicotiana benthamiana and their correlation with the levels of developmental miRNAs

    Directory of Open Access Journals (Sweden)

    Amin Imran

    2011-05-01

    Full Text Available Abstract Background Whitefly-transmitted geminiviruses (begomoviruses are a major limiting factor for the production of numerous dicotyledonous crops throughout the world. Begomoviruses differ in the number of components that make up their genomes and association with satellites, and yet they cause strikingly similar phenotypes, such as leaf curling, chlorosis and stunted plant growth. MicroRNAs (miRNAs are small endogenous RNAs that regulate plant growth and development. The study described here was aimed at investigating the effects of each virus encoded gene on the levels of developmental miRNAs to identify common trends between distinct begomoviruses. Results All genes encoded by four distinct begomoviruses (African cassava mosaic virus [ACMV], Cabbage leaf curl virus [CbLCuV], Tomato yellow leaf curl virus [TYLCV] and Cotton leaf curl virus/Cotton leaf curl betasatellite [CLCuV/CLCuMB] were expressed from a Potato virus X (PVX vector in Nicotiana benthamiana. Changes in the levels of ten miRNAs in response to the virus genes were determined by northern blotting using specific miRNA probes. For the monopartite begomoviruses (TYLCV and CLCuMV the V2 gene product was identified as the major symptom determinant while for bipartite begomoviruses (ACMV and CbLCuV more than one gene appears to contribute to symptoms and this is reflected in changes in miRNA levels. The phenotype induced by expression of the βC1 gene of the betasatellite CLCuMB was the most distinct and consisted of leaf curling, vein swelling, thick green veins and enations and the pattern of changes in miRNA levels was the most distinct. Conclusions Our results have identified symptom determinants encoded by begomoviruses and show that developmental abnormalities caused by transient expression of begomovirus genes correlates with altered levels of developmental miRNAs. Additionally, all begomovirus genes were shown to modulate miRNA levels, the first time this has been shown to

  8. Effects of CO[sub 2] concentration on photosynthesis, transpiration and production of greenhouse fruit vegetable crops

    Energy Technology Data Exchange (ETDEWEB)

    Nederhoff, E.M.

    1994-10-25

    The effect of the CO[sub 2] concentration of the greenhouse air (C) in the range 200 to 1100 [mu]mol mol[sup -1] was investigated in tomato (Lycopersicon esculentum Mill.), cucumber (Cucumis sativus L.), sweet pepper (Capsicum annuum L.) and eggplant (Solanum melongena L.), grown in greenhouses. The effect of C on canopy net photosynthetic CO[sub 2] assimilation rate (or photosynthesis, P) was expressed by a set of regression equations, relating P to PAR, C and LAI. A rule of thumb ('CO[sub 2]-rule') was derived, approximating the relative increase of P caused by additional CO[sub 2] at a certain C. This CO[sub 2]-rule is: X = (1000/C)[sup 2] * 1.5 (X in % per 100 [mu]mol[sup -1], and C in [mu]mol mol[sup -1]). Two models for canopy photosynthesis were examined by comparing them with the experimental photosynthesis data. No 'midday depression' in P was observed. The effects of C on leaf conductance (g) and on rate of crop transpiration (E) were investigated. An increase of 100 I[mu]mol mol[sup -1] ' in C reduced g by about 3-4% in sweet pepper, tomato and cucumber and by about 11% in eggplant. The effect of C on E was analyzed by combining the regression equation for g with the Penman-Monteith equation for E. C had only a relatively small effect on E, owing to thermal and hydrological feedback effects. The decoupling of g and E was quantified. No time-dependent variation or 'midday depression' in E was observed, and no significant effect of C on average leaf temperature was established. In five experiments, the effect of C on growth and production and on specific features were analyzed; fruit production (dry weight) was most affected by C in sweet pepper; fresh weight fruit production per unit CO[sub 2] was highest in cucumber; fruit quality was not influenced by C. High C promoted the 'short leaves syndrome' in tomato and 'leaf tip chlorosis' in eggplant, probably related to calcium and boron translocation

  9. Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula

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    Oliver Richard P

    2008-03-01

    Full Text Available Abstract Background Knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. In this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by Phoma medicaginis, an economically important necrotrophic pathogen of Medicago spp., was examined in the model legume M. truncatula. Results Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 × A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P Phoma medicaginis one (rnpm1 genetically mapped to the top arm of linkage group 4 (LG4. rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1–5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P rnpm2, was located on the lower arm of LG8 in the SA27063 × SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs are apparent in the genomic sequence of the reference accession A17 at the

  10. Produtividade e qualidade dos frutos da laranjeira 'Pêra' clone IAC em 16 porta-enxertos na região de Bebedouro-SP Yield and fruit quality of 'Pêra' sweet orange clone IAC on 16 rootstocks in Bebedouro region, State of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Eduardo Sanches Stuchi

    2004-08-01

    and chemical fruit characteristics such as fruit size, total soluble solids, acidity, ratio juice content and technological index of 'Pera' IAC sweet orange [Citrus sinensis (L. Osbeck], in a high inoculum pressure area of citrus variegated chlorosis (CVC. The spacement was 6.0 m between rows and 3.5 m between trees. The experimental design used was randomized blocks, with three replications and two trees per plot. The rootstocks tested were 'Sun Chu Sha Kat' mandarin (Citrus reticulata, 'Pectinífera' (C. reticulata, 'Shekwasha' (C. depressa Hayata, 'Pectinífera/Shekwasha' (C. depressa Hayata, 'Batangas' (C. reticulata, 'Oneco' (C. reticulata, citrangor [citrange (Poncirus trifoliata Raf. x C. sinensis x C. sinensis], citrandarin (C. sunki hort. ex Tanaka x Poncirus trifoliata L. Raf. cv. English, 'Sunki' (C. sunki, 'Suen-Kat' (C. sunki, Nasnaran (C. amblycarpa Ochse, 'Venezuela' mandarin (C. reticulata, 'Heen Naran' mandarin (C. lycopersicaeformis, 'Cravo' (C. limonia Osbeck x 'Cleopatra' (C. reshni hort ex Tanaka, 'Cravo' (C. limonia, 'Cleopatra' (C. reshni. CVC intensity was different due to rootstocks effects and not related with yield until the fourth year of production. With the exception of the Nasnaran mandarin the rootstocks induced initial fruit production and quality similar to 'Cravo'.

  11. Cultivo hidropônico de alface com água salobra subterrânea e rejeito da dessalinização em Ibimirim, PE Hydroponic lettuce production with brackish groundwater and desalination waste in Ibimirim, PE, Brazil

    Directory of Open Access Journals (Sweden)

    Alexandre N. Santos

    2010-09-01

    lettuce of plants. The plants exhibited general chlorosis at the beginning of the cycle, but this symptom was not verified at the harvest. The variety 'Vera' had a lower absolute growth and yield than the 'AF-1743'. On the other hand, the percent reduction for both varieties was similar - the shoot fresh matter accumulation was decreased by 17.06 and 15.74% (dS m-1-1 for 'Vera' and 'AF-1743', respectively.

  12. Prokaryotic Expression and Antiserum Preparation of the Coat Protein of Cymbidium Mosaic Virus%建兰花叶病毒CP基因的原核表达及抗血清制备

    Institute of Scientific and Technical Information of China (English)

    罗金水

    2009-01-01

    通过间接酶联免疫检测和电镜观察对从福建省漳州市采集的卡特兰病样进行检测,证明样品感染了建兰花叶病毒.设计一对特异性引物,扩增并克隆病毒分离物的外壳蛋白基因,随后将目的基因插入pET-29a(+)中构建相应的原核表达载体.目的蛋白经诱导表达及纯化后免疫家兔并获得了特异性抗血清.Westem blot检测结果表明.抗血清与诱导表达的CyMV外壳蛋白发生特异性反应.间接酶联免疫法检测结果表明,抗血清可检测病汁液的最低稀释度达1:51 200,最佳工作浓度为1:1000,病汁液灵敏度为0.39 mg/mL,而与TMV等11种同源或异源病毒均无明显的血清学交叉反应.%Cymbidium mosaic virus (CyMV) is one of the most important and worldwide viruses attacking orchids. This virus causes the symptoms of mosaic,chlorosis,necrosis and malformation in the orchids,and has a high economic impact to the orchid industry. Cattleya plants contracted with a disease were collected as samples from Zhangzhou,Fujian,and were identified to be infected with Cymbidium mosaic virus by using ID -ELISA and electronic microscopy assay. One pair of specific primers was designed for amplification of the coat protein(CP) gene from the samples infected with CyMV. The open reading frame encoding CP of CyMV isolate obtained from Zhangzhou,Fujian is 672 bp,encoding a 23.6 ku protein with 223 aa. The expected CP gene was then inserted into the pET-29a(+)vector for prokaryotic expression. And the aimed protein was purified and used to immune the rabbit for antiserum preparation. According the result of ID-ELISA analysis,specific rabbit anti-CyMV serum was prepared with a high titre of 1:51 200,a working concentration of 1:1 000 and sap sensitivity of 0.39 mg/mL. Western blot analysis confirmed that the antiserum reacted strongly and specifically to the CP of CyMV. There were no cross reactions between the antiserums and 11 species of homologous or heterologous

  13. Intoxicação de espécies de eucalipto submetidas à deriva do glyphosate Intoxication of eucalypt species under glyphosate drift

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    L.D. Tuffi Santos

    2006-06-01

    glyphosate drift, by means of herbicide subdoses, on the growth of five eucalypt species. The factorial model used five species (Eucalyptus urophylla, E. grandis, E. pellita, E. resinifera and E. saligna and five subdoses (0, 43.2, 86.4, 172.8, and 345.6 g ha-1 glyphosate arranged in a randomized block design, with four repetitions. Glyphosate applications were performed on the plants in such a way as to avoid reaching the upper third part of the plants 23 days after seed planting. The intoxication symptoms caused by glyphosate were similar for the different species, as characterized by wilt, chlorosis and leaf curling and in the case of larger doses, by necrosis and leaf senescence. Plants treated with subdoses above 86.4 g ha-1 glyphosate were severely intoxicated and were affected in their growth, with smaller height, diameter and less dry matter after 45 days of herbicide application. Among the species studied, E. resinifera showed to be the most tolerant to glyphosate drift, displaying the lowest intoxication values and greatest height and diameter increases, a fact not observed in the other species.

  14. HOSPEDANTES DE Ralstonia solanacearum EN PLANTACIONES DE BANANO Y PLÁTANO EN COLOMBIA HOSTS OF Ralstonia solanacearum ON BANANA AND PLANTAIN PLANTATIONS IN COLOMBIA

    Directory of Open Access Journals (Sweden)

    Mónica Obregón Barrios

    2008-12-01

    this bacterium has been associated with asymptomatic weeds found in high populations which facilitates the survival and permanence in the field. To determine the wild symptomatic and asymptomatic host in affected areas of banana and plantain plantations in el Valle del Cauca, Quindío and Urabá, it was carried out the collection of frequent weeds around the infected focus and isolatioin of the bacterium in SMSA culture medium. 124 isolates were subjected to biochemical and pathogenicity test in plantain and banana plants under environmental conditions in El Valle del Cauca and Urabá. In the pathogenicity test 67 out of 124 that were evaluated were positive, showing the typical symptoms such of the disease such as: wilting, chlorosis, leaf yellowing and dead plants. New bacterial weed host species have been found: Chaptalia nutans, Seneciodes cinerea, Tripogandra glandulosa, Plenax hirtus, Peperomia pellucida, Tripogandra cumanenses, Desmodium sp, and Cissus sicyoides (Vitaceae. The latter belongs to the Vitaceae family, which corresponds to the report of a new host family. The presence of the bacterium was confirmed in wild host previously reported.

  15. Efeitos do boro em algodoeiro cultivado em condições de casa de vegetação Effects of boron application to cotton plant in a greenhouse study

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    Nelson M. da Silva

    1979-01-01

    the aboveground portion of plant or in leaf blade, increased according to the levels of fertilization used. Boron concentration in deficient plant leaves varied between 10 and 39ppm of B, with an average of 19ppm, while leaves from plants exhibiting serious symptons of toxicity showed values higher than 590ppm of B. Stunted plants, excessively branched, having enlarged and dark nodes, deformed cotyledones and leaf blades, short leaf petioles with dark rings and pith necrosis, and abnormally flowers, are related as boron-deficients. Chlorosis of leaf, in the margin or among the veins, was considered as symptom of toxicity.

  16. Optimización de las condiciones de inoculación por biobalística de un Begomovirus en tomate y tabaco

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    Karina López-López

    2013-12-01

    living infected plant and extensive facilities to maintain the insect. Whitefly inoculations can also be problematic because of their preferential feeding habits on certain plants. Mechanical inoculation of Begomovirus is possible but generally at low rates and not in all cases. For this reason, particle bombardment (biolistic of DNA viral as an inoculum was developed. The possibility of using the Helios Gen System Gun (Biorad®, a biolistic hand-held device, for transmitting Begomovirus bipartite to tomato and tobacco plants was assayed and optimized. Biolistic inoculation was carried out with the hand held device at 220 or 320 psi, applying 1 or 2 shots /plant and using gold particles of 0.6 or 1.6µm in size. Characteristic symptoms of viral disease (chlorosis, mosaic and leaf deformation appeared 3 weeks post-inoculation in the newly developing leaves. Replication of the viral DNA in plants was confirmed by Polymerase Chain Reaction. All bombarded plants became infected when biolistic inoculation was carried out with the hand held device at 320psi and using 1.6 µm gold particles in size. To our knowledge, this is the first report in Colombia of successful direct inoculation of tomato and tobacco plants with Begomovirus bipartite geminivirus using a biolistic hand-held device.Key words: geminivirus, Solanum lycopersicum, Nicotiana tabacum, N. benthamiana, Bemisia tabaci. 

  17. Efecto depresivo de los agentes causales de las pudriciones secas en plantas producidas in vitro de malanga (Xanthosoma sagittifolium

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    Ernesto Espinosa Cuellar

    2012-06-01

    oxysporum Schlecht, Rhizoctonia solani Kühn and Sclerotium rolfsii Sacc isolated from infected plants with symptoms of poor development, chlorosis, leaf necrosis and rot the roots. Treatments consisted of the isolation of the three fungi separately, the mixture of the three fungi and uninoculated control. Previously acclimatized plants were planted in chambers had dimensions 0.90 x 0.90 x 0.90 m, in randomized complete block with four replications. 100 plants were inoculated for each treatment and control is left as an equal number of uninoculated plants was evaluated in each case the plant height, number of roots per plant and number of diseased roots and subsequently determined the fresh weight and dry the roots and foliage. Was harvested at 10 months after planting and assessed some components of performance, as the number of corms and cormels and their fresh weight, as the intensity of damage at the time of harvest. The results showed that the fungal pathogens Fusarium oxysporum Schlecht, Rhizoctonia solani Kühn and Sclerotium rolfsii Sacc associated with dry rot caused a depressive effect on taro plants grown in vitro produced cameras. The mixture of these three fungi was very aggressive, resulting in reduced plant height, fresh weight of leaves and number of roots, corms and cormels. Key words: Taro, dry rot, fungus.

  18. Superfícies de resposta do tangor 'Murcott' à fertilização com N, P e K Response models of 'Murcott' tangor to N, P, and K fertilization

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    Dirceu Mattos Junior

    2004-04-01

    Full Text Available O valor de comercialização no mercado de fruta fresca e a maior resistência a doenças, como o declínio e a clorose variegada dos citros, comparado às variedades de laranjas, estimularam a produção de tangerinas e de 'Murcott' na última década. Por outro lado, faltam informações seguras para o diagnóstico das necessidades de adubação para esses cítricos. Assim, o presente trabalho foi planejado com os objetivos de estudar a demanda por nutrientes e estabelecer doses de fertilizantes para maximizar a produtividade e a qualidade dos frutos de tangor 'Murcott' e definir critérios de diagnóstico da análise de folhas para o manejo nutricional dessas plantas. O experimento foi desenvolvido durante seis anos, num pomar comercial da variedade Murcott sobre limoeiro 'Cravo', com 4 anos de idade. Os tratamentos foram arranjados no delineamento fatorial fracionado, do tipo ½ (4³ e constituídos por níveis de N (30; 100; 170 e 240 kg N ha-1, de P (20; 80; 140 e 200 kg ha-1 de P2O5 e de K (30; 110; 190 e 270 kg ha-1 de K2O. O N aumentou a produção média do período, enquanto o efeito do K foi negativo. Não houve efeito significativo para doses de P. A produção máxima de frutos foi obtida com as doses 155; 20 e 30 kg ha-1, respectivamente, de N, P2O5 e K2O, enquanto, para otimizar o tamanho dos frutos, foi necessário elevar a doses de K para 270 kg ha-1 de K2O. Outras características de qualidade dos frutos também foram estudas, bem como critérios para a interpretação de resultados de análises de folhas.The Brazilian production of mandarins and 'Murcott' tangor has increased during the 1990's due to superior value of fruit for commercialization and higher resistance to citrus diseases, i.e.: citrus variegated chlorosis, compared to sweet oranges. On the other hand, there is a lack of information to establish optimum nutrient requirements for such varieties. Therefore, the present work aimed to study the response of 'Murcott

  19. Host colonization differences between citrus and coffee isolates of Xylella fastidiosa in reciprocal inoculation Diferenças em colonização do hospedeiro por isolados de Xylella fastidiosa de citros e cafeeiro em inoculações recíprocas

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    Simone de Souza Prado

    2008-01-01

    Full Text Available Citrus variegated chlorosis (CVC and coffee stem atrophy (CSA are important diseases in Brazil associated with closely-related strains of Xylella fastidiosa, but little is know about host aoverlappingnd importance of citrus and coffee as inoculum sources of these strains. In this study, reciprocal-inoculation experiments were performed to determine if CVC and CSA isolates are biologically similar within citrus and coffee plants. These two hosts were mechanically inoculated with a CVC and a CSA isolate of X. fastidiosa at four concentrations ranging between10³ and 10(9 colony forming units CFU mL-1. At two, four and eight months after inoculation, the infection efficiency and bacterial populations of the isolates in each host were determined by culturing. The CVC isolate infected both citrus and coffee plants, but developed lower populations in coffee. The CSA isolate did not colonize citrus. Inoculation of coffee plants with the CVC isolate resulted in low rates of infection and required an inoculum concentration ten-fold higher than that necessary to obtain a similar (25% rate of infection in citrus. The relatively low infection rates and bacterial numbers of the CVC isolate in coffee plants compared with those observed in citrus suggest that coffee is not a suitable host to serve as a source of inoculum of the CVC strain for primary spread to citrus or within coffee plantations.Clorose variegada dos citros (CVC e atrofia dos ramos do cafeeiro (ARC são doenças importantes no Brasil, associadas a estirpes de Xylella fastidiosa que são geneticamente próximas. Entretanto, pouco se sabe a respeito de plantas hospedeiras em comum e da importância de citros e cafeeiro como fontes de inóculo dessas estirpes. Neste estudo, realizaram-se experimentos de inoculação recíproca para determinar se isolados de X. fastidiosa de CVC e de ARC são biologicamente semelhantes em plantas de citros e café. Estes dois hospedeiros foram mecanicamente

  20. Danos visuais e anatômicos causados pelo glyphosate em folhas de Eucalyptus grandis Visible and anatomic damages caused by glyphosate in Eucalyptus grandis leaves

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    L.D. Tuffi Santos

    2008-03-01

    effects of four commercial glyphosate formulations under simulated spray drift (Scout®, Roundup NA®, Roundup transorb® and Zapp QI® on the morphoanatomy of six Eucalyptus grandis clones (UFV01, UFV02, UFV03, UFV04, UFV05 and UFV06. Following glyphosate application (129.6 g ha-1, symptoms were monitored daily and, at 14 days, leaf samples from the regions without visible symptoms were collected for microscopic analysis. All clones presented chlorosis and necrosis at the fourth day of glyphosate exposure, regardless of the formulation used. The UFV04 clone did not show any anatomical damage. The other clones suffered plasmolysis, cellular collapse, hypertrophy and formation of cicatrisation tissue. However, changes in leaf blade thickness were not observed. Plants exposed to Roundup transorb® presented the greatest visible intoxication percentage. Anatomically, plants exposed to Roundup NA® showed a higher number of damages. Analysis considering both anatomic and visible damages showed that UFV06 clone was the most susceptible to the formulations tested. The results confirmed the diagnostic and prognostic value of visual and anatomical analysis, respectively, and showed that these parameters are essential to evaluate clone susceptibility and the the phytotoxic potential of herbicides.

  1. Locais e período de alimentação da cigarrinha vetora de Xylella fastidiosa, Bucephalogonia xanthophis (Berg (Hemiptera: Cicadellidae, em mudas cítricas Feeding sites and food intake of Bucephalogonia xanthophis (Berg (Hemiptera: Cicadellidae, a sharpshooter vector of Xylella fastidiosa, on citrus plants

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    Marcelo Pedreira de Miranda

    2008-12-01

    Full Text Available A cigarrinha Bucephalogonia xanthophis (Berg (Hemiptera: Cicadellidae é um importante vetor da bactéria Xylella fastidiosa, agente causal da clorose variegada dos citros. Este trabalho teve como objetivo identificar o local preferido de alimentação e o período de maior atividade alimentar desta cigarrinha em citros, no sentido de elucidar o comportamento alimentar relacionado à transmissão da bactéria. O local de alimentação foi estudado em ensaio de escolha, no qual 30 insetos adultos foram liberados em gaiolas de observação (n = 10 contendo uma muda de laranja-doce [Citrus sinensis (L. Osbeck]. Após 1; 15; 21; 25; 39; 45 e 49 h da liberação, contaram-se os insetos na parte superior (ramos com brotações e inferior (haste principal, até H"40 cm de altura da muda. Nos ramos da parte superior, avaliou-se a preferência entre a haste, o pecíolo e o limbo foliar. Em um segundo ensaio, 20 machos e 20 fêmeas de B. xanthophis foram confinados individualmente sobre a haste de 'seedlings' de laranja-doce para determinar os períodos de alimentação, quantificando-se a excreção de 'honeydew' (medida indireta da ingestão em períodos sucessivos de dia e noite, durante 48 h. A maioria dos indivíduos de B. xanthophis preferiu a haste dos ramos novos (62%, na parte superior da muda cítrica (91%. Nos 'seedlings', observou-se maior volume de excreção e proporção de indivíduos excretando durante a fotofase, independentemente do sexo. Portanto, em estudos de transmissão de X. fastidiosa, deve-se considerar a preferência de B. xanthophis pela haste de brotações cítricas e sua maior atividade alimentar durante a fotofase.The sharpshooter Bucephalogonia xanthophis (Berg (Hemiptera: Cicadellidae is an important vector of Xylella fastidiosa, a bacterium that causes citrus variegated chlorosis. This study aimed to identify the preferred feeding sites and periods of this vector on citrus, in order to improve our understanding of the

  2. Monitoramento populacional das cigarrinhas vetoras de Xylella fastidiosa, através de armadilhas adesivas amarelas em pomares comerciais de citros Population monitoring of leafhopper vectors of Xylella fastidiosa, through yellow sticky traps in commercial citrus orchards

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    Rúbia de Oliveira Molina

    2010-12-01

    Full Text Available A Clorose variegada dos citros (CVC é uma doença causada pela bactéria de xilema Xylella fastidiosa Wells. A disseminação ocorre por meio de insetos vetores pertencente à ordem Hemiptera, família Cicadellidae (subfamília Cicadellinae, os quais transmitem a bactéria depois de se alimentarem em plantas contaminadas. Neste trabalho, objetivou-se identificar e monitorar as espécies de cigarrinhas vetoras em um pomar comercial no município de Paranavaí, Paraná. O experimento foi realizado em um talhão comercial de laranja doce (Citrus sinensis (L. Osbeck, variedade Pera, com 1.000 plantas de dez anos de idade. A amostragem foi realizada por meio de armadilhas adesivas amarelas, distribuídas na área periférica e central do pomar, com duas repetições por rua amostrada. As etiquetas foram distribuídas entre a 5ª e 30ª plantas em 10 ruas, totalizando 20 armadilhas que foram renovadas no pomar, a cada trinta dias, durante o período de avaliação que foi entre junho de 2005 e setembro de 2006. As principais espécies de Cicadellinae capturadas foram Acrogonia citrina Marucci & Cavichioli, Dilobopterus costalimai Young e Macugonalia cavifrons Stal. Essas espécies apresentaram ocorrência constante e frequência de 3,97%, 4,2%, 13,0% respectivamente, em relação ao total de cigarrinhas coletadas.Citrus variegated chlorosis (CVC is the disease caused by the bacteria Xylella fastidiosa Wells. Dissemination occurs through insect vectors belonging to the order Hemiptera, family Cicadellidae (subfamily Cicadellinae, which transmit the bacteria after feeding on infected plants. The objective of this study was to identify the species of insect vectors in an orchard in the municipality of Paranavaí, in the State of Paraná. The experiment was conducted in a commercial stand of sweet orange (Citrus sinensis (L. Osbeck, Pêra variety with 1,000 10-year-old plants. Monitoring was performed using yellow sticky traps, distributed in the central

  3. Reação de variedades e clones de laranjas a Xylella fastidiosa Reaction of oranges varieties and clones to Xylella fastidiosa

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    Paulo Sergio de Souza

    2006-04-01

    Full Text Available A clorose variegada dos citros (CVC é uma doença grave, causada por Xylella fastidiosa. As medidas usuais de controle mostram-se pouco eficientes ou práticas e com alto custo. Dessa forma, o uso de variedades resistentes e/ou tolerantes desponta como a alternativa mais eficiente, razão pela qual se julgou oportuna a realização deste trabalho. O presente estudo teve como objetivo avaliar o comportamento de variedades e clones de laranjas introduzidas em relação a X. fastidiosa. Foram estudados 59 variedades e clones de laranjas doces e 2 de laranjas azedas introduzidos da França, Itália e Portugal. O delineamento experimental foi o de blocos casualizados (DBC, com 62 tratamentos e 4 repetições, incluindo a variedade 'Pêra', como padrão. Cada parcela continha duas plantas, sendo uma inoculada e a outra sem inoculação. Para a inoculação do patógeno, foi empregado o método de encostia, utilizando-se de mudas infectadas. Para a avaliação da incidência da doença, utilizou-se de dados qualitativos, positivos ou negativos, enquanto para severidade empregou-se escala de notas, que foi estabelecida baseando-se nos sintomas de CVC, confirmados através dos testes de PCR. As variedades de laranjas azedas Beja e Sr. Pinto e as laranjas doces Navelina ISA 315, Navelina SRA 332 e Newhall Navel SRA 343 não apresentaram sintomas em folhas até 27 meses após a inoculação.Citrus variegated chlorosis (CVC is a serious disease, caused by Xylella fastidiosa, being the most important to the Brazilian citriculture. The usual measures of control show less efficient or practice and they are very expensive. The use of resistant varieties is showed as the most efficient, consisting the aimed of this research. The objective of the present work was study the behavior of varieties and clones introduced in relation to X. fastidiosa. Were studied 59 varieties and clones of sweet oranges and 2 sour oranges introduced from France, Italy and Portugal

  4. Deficiência hídrica agrava os sintomas fisiológicos da clorose variegada dos citros em laranjeira 'Natal' Water deficiency intensifies physiological symptoms of citrus variegated clorosis in 'Natal' sweet orange plants

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    Eduardo Caruso Machado

    2007-01-01

    Full Text Available A clorose variegada dos citros (CVC é uma doença que tem promovido sérios prejuízos aos laranjais das regiões Norte e Nordeste do Estado de São Paulo, onde a deficiência hídrica e as altas temperaturas são mais frequentes. Assim, este trabalho objetivou a avaliação do efeito da deficiência hídrica no desenvolvimento de sintomas fisiológicos em laranjeira 'Natal' com CVC. Foram realizadas medidas do potencial da água na folha, transpiração, condutância estomática e assimilação de CO2, em laranjeiras em condições naturais e submetidas à irrigação. O delineamento experimental foi em blocos ao acaso com cinco repetições. A condutância estomática, a transpiração diária e o potencial da água na folha foram menores nas plantas com CVC. A assimilação diária de CO2 foi menor nas laranjeiras com CVC mesmo quando irrigadas. De fato, a irrigação diminuiu o efeito da CVC, porém não impediu o estabelecimento da doença em laranjeiras inoculadas com Xylella fastidiosa. Em relação aos demais tratamentos, as plantas infectadas e mantidas sob condições naturais (sem irrigação apresentaram maior comprometimento das trocas gasosas, mesmo quando as avaliações fisiológicas foram feitas em período úmido (verão.Citrus variegated chlorosis (CVC is a disease that has caused serious economical losses in citrus grove located in the North and Northeastern regions of São Paulo State, where water deficiency and high temperature occur frequently. Therefore, the aim of this work was to evaluate the influence of water deficiency on the development of physiological symptoms in 'Natal' sweet orange plants with CVC. Measurements of leaf water potential, transpiration, stomatal conductance e CO2 assimilation were taken in plants under natural conditions and submitted to irrigation. The experimental design was in randomized blocks, with five replications. Stomatal conductance, daily transpiration and leaf water potential were

  5. Spatial-temporal distribution of sharpshooters (Hemyptera: Cicadellidae insect vectors of Xylella fastidiosa in citrus orchards = Distribuição espaço-temporal de cigarrinhas (Hemiptera: Cicadellidae vetores da Xylella fastidiosa em pomares cítricos

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    Rúbia de Oliveira Molina

    2016-07-01

    Full Text Available Variegated chlorosis (CVC is a citrus disease, reported initially in the northwest of São Paulo state and in the Triângulo Mineiro region of Minas Gerais state in 1987. The CVC is caused by the xylematic bacteria Xylella fastidiosa. The bacteria is spread through contaminated bubbles or by insect vectors belonging to the Hemyptera order and Cicadellidae family. The aimed of this study was to identify the species of Xylella fastidiosa insect vector and to determine its spatial and temporal distribution in commercial orchards of sweet orange [Citrus sinensis (L. Osbeck]. The experiment was conducted in a commercial area of sweet orange, Pêra variety, grafted on Rangpur lime, located in northwest Paraná. For sampling, yellow sticky traps were used, distributed in the peripheral and central area of the orchard with four replicates per street sampled (5, 30, 55 and 80th plant, each plant was considered a sample unit. Were evaluated ten plots per street, totaling 40 traps for sampling. Every thirty days during the evaluation period, the traps were renewed in the orchard. The main species caught were Acrogonia citrine and Dilobopterus costalimai. The highest incidences occurred from winter to spring, and summer to autumn of the next year. According to the geostatistical analysis, the spatial distribution of these species concentrated in the peripheral zone of the portion where a higher incidence of these species was captured. The results show that it is necessary to adopt pest management practices for the Cicadellidae vector of X. fastidiosa differentiated in space and time. = A clorose variegada dos citros (CVC é uma doença de plantas cítricas, constatada, em 1987, inicialmente nos municípios do noroeste paulista e da região do triângulo mineiro. Ela é causada por uma bactéria de xilema, denominada Xylella fastidiosa. Sua disseminação ocorre através de borbulhas contaminadas ou por meio de insetos vetores da ordem Hemiptera e fam

  6. Ingestão de seiva do xilema de laranjeiras 'Pêra' e 'Valência' (Citrus sinensis (L. Osbeck sadias e infectadas por Xylella fastidiosa, pelas cigarrinhas vetoras Oncometopia facialis e Dilobopterus costalimai (Hemiptera: Cicadellidae Xylem sap ingestion form healthy "Pera" and "Valencia" sweet orange (Citrus sinensis (L. Osbeck and infected ones by Xylella fastidiosa, Oncometopia facialis and Dilobopterus costalimai (Hemiptera: Cicadellidae

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    Luiz Henrique Montesino

    2006-08-01

    Full Text Available Estudou-se o efeito da infecção pela bactéria Xylella fastidiosa, agente causal da Clorose Variegada dos Citros (CVC, sobre a taxa de ingestão de seiva do xilema de plantas cítricas por duas espécies de cigarrinhas vetoras (Hemiptera: Cicadellidae. Foram utilizados pés-francos de laranjeira-doce (Citrus sinensis das variedades 'Pêra' e 'Valência', infectadas por X. fastidiosa da linhagem 9a5c, por meio de inoculação mecânica. Os insetos utilizados nos experimentos foram coletados em campo, sendo um representante da Tribo Cicadellini (Dilobopterus costalimai e um da Proconiini (Oncometopia facialis. A taxa de ingestão de seiva do xilema por O. facialis foi quantificada nos ramos das plantas e a de D. costalimai nas folhas e ramos, por meio da avaliação do volume do líquido (honeydew excretado por unidade de tempo. O consumo pela cigarrinha O. facialis nas plantas doentes foi menor do que nas plantas sadias. Na variedade 'Pêra' doente, o consumo foi baixo, não permitindo a quantificação da seiva eliminada. Na 'Pêra' sadia e na 'Valência' doente e sadia, O. facialis apresentou valores expressivos de excreção, com maior alimentação no período diurno. Nas plantas sadias das duas variedades, o consumo pela cigarrinha D. costalimai foi maior do que nas plantas com CVC. Comparando-se as variedades, o consumo foi superior na variedade 'Valência', e, em relação às partes da planta, folha e ramo, a taxa de ingestão foi maior no ramo das duas variedades, apresentando consumo maior no período diurno.It was studied the effect of Xylella fastidiosa infection, causal agent of Citrus Variegated Chlorosis (CVC, on the xylem sap ingestion rate of citrus plants by two sharpshooters species (Hemiptera: Cicadellidae. Seedlings of sweet orange Pera and Valencia (Citrus sinensis were used and infected by X. fastidiosa, strain 9a5c, obtained by mechanical inoculation. The insects used in the experiments were collected in the field, one

  7. 打孔塞入法治疗果树缺铁黄叶病%Therapy Study of Chlorotic Disorder of Fruit Trees Caused by Iron Deficiency through Punched Hole

    Institute of Scientific and Technical Information of China (English)

    王满平; 孙占育; 孙志强; 田芳银; 王小军

    2012-01-01

    Researches selected out eight kinds of iron-contained compounds and insert them to the holes dug on the trunks, in order to cure the fruit chlorosis reduced by iron deficiency economically, safely as well as efficiently,and overcome the poor effects of fertilizing iron on soil or tree leaves and the defects of injecting green-recovering potion from tree trunks, such as restriction by season, poor safety condition and complex operation. These compounds can be divided into four types including: (1) the soluble inorganic ferrous salt FeSO4 ·7H2O and FeCl2 ·4H2O; (2) the soluble inorganic ferric salt Fe2(SO4)3 and FeCl3 ·6H2O; (3) the hard dissolved iron compounds FeC2O4 and Fe2O3; (4) Iron complex ammonium ferrous sulphate Fe(NH4 )2 (SO4 )2 ·6H2O and ferrous citrate. The results showed that several iron-contained compounds can cure chlorotic disorder of fruit trees caused by iron-deficiency within 6~7 days,even the white leaves totally recover to green within 20 days. Fe(NH4 )2 (SO4)2 ·6H2O is the most economic, efficient and safest compound; FeSO4 ·7H2O is the second best. The research also paved a new way for treatment of other trace elements deficiency diseases.%为了经济、安全、高效地治疗果树因缺铁而引发的黄叶病,克服目前土壤和叶面施铁疗效差,树干注射复绿剂受季节限制、安全性差、操作复杂的缺陷,选用4类8种含Fe化合物(易溶性二价无机铁盐FeSO4·7H2O和FeCl2·4H2O,易溶性三价无机铁盐Fe2 (SO4)3和FeCl3·6H2O,难溶性Fe2O3和FeC2O4,铁络合物Fe( NH4)2(SO4)2·6H2O和FeC6O2H6),在树干上打孔后将其塞入.结果表明,多种含铁化合物都能使果树缺铁黄化病在第6至第7天开始复绿,20 d后使已经白化的叶片也能彻底恢复绿色,其中Fe(NH4)2(SO4)2·6H2O最为经济、安全、高效,FeSO4·7H2O次之.

  8. Effects of mutated replicase and movement protein genes on attenuation of tobacco mosaic virus

    Institute of Scientific and Technical Information of China (English)

    YANG; Gong; (

    2001-01-01

    [1]Banerjee, N., Wang, J. Y., Zaitlin, M., A single nucleotide change in the coat protein gene of tobacco mosaic virus is involved in the induction of severe chlorosis, Virology, 1995, 207: 234-239.[2]Dawson, W. O., Bubrick, P., Grantham, G. L., Modifications of the tobacco mosaic virus coat protein gene affecting replication, movement, and symptomatology, Mol. Plant Pathol., 1988, 78: 783-789.[3]Lu, B., Stubbs, G., Culver, J. N., Coat protein interactions involved in tobacco mosaic tobamovirus cross-protection, Virology, 1998, 248: 188-198.[4]Bao, Y. M., Carter, S. A., Nelson,R. S., The 126- and 183-kilodalton proteins of tobacco mosaic virus, and not their common nucleotide sequence, control mosaic symptom formation in tobacco, J. Virol., 1996, 70: 6378-6383.[5]Holt, C. A., Hodgson, A. J., Coker, F. A. et al., Characterization of the masked strain of tobacco mosaic virus: identification of the region responsible for symptom attenuation by analysis of an infectious cDNA clone, Mol. Plant-Microbe Interact., 1990, 3: 417-423.[6]Nishiguchi, M., Kikuchi, S., Kiho, Y. et al., Molecular basis of plant viral virulence, the complete nucleotide sequence of an attenuated strain of tobacco mosaic virus, Nucleic Acids Res., 1985, 13: 5585-5590.[7]Watanabe, Y., Morita, N., Nishiguchi, M.et al., Attenuated strains of tobacco mosaic virus reduced synthesis of a viral protein with a cell to cell movement function, J. Mol. Biol., 1987, 194: 699-704.[8]Lewandowski, D. J., Dawson, W. O., A single amino acid change in tobacco mosaic virus replicase prevents symptom production, Mol. Plant-Microbe Interact., 1993, 6: 157-160.[9]Yang, G., Qiu, B. S., Cloning and infectivity analysis of the cDNAs of tobacco mosaic virus (tomato strain) and its attenuated virus (N14) genomes, Chinese Journal of Biotechnology (in Chinese), 2000, 16: 207-210.[10]Yang, G., Liu, X. G., Qiu, B. S., Complete nucleotid sequences and genome structures of two Chinese tobacco

  9. Behavior of Eucalyptus grandis and E. cloeziana seedlings grown in arsenic-contaminated soil Comportamento de mudas de E. grandis E. eucalyptus cloeziana cultivadas em solo contaminado por arsênio

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    Roseli Freire Melo

    2010-06-01

    Full Text Available Arsenic has been considered the most poisonous inorganic soil pollutant to living creatures. For this reason, the interest in phytoremediation species has been increasing in the last years. Particularly for the State of Minas Gerais, where areas of former mining activities are prone to the occurrence of acid drainage, the demand is great for suitable species to be used in the revegetation and "cleaning" of As-polluted areas. This study was carried out to evaluate the potential of seedlings of Eucalyptus grandis (Hill Maiden and E. cloeziana F. Muell, for phytoremediation of As-polluted soils. Soil samples were incubated for a period of 15 days with different As (Na2HAsO4 doses (0, 50, 100, 200, and 400 mg dm-3. After 30 days of exposure the basal leaves of E. cloeziana plants exhibited purple spots with interveinal chlorosis, followed by necrosis and death of the apical bud at the 400 mg dm-3 dose. Increasing As doses in the soil reduced root and shoot dry matter, plant height and diameter in both species, although the reduction was more pronounced in E. cloeziana plants. In both species, As concentrations were highest in the root system; the highest root concentration was found in E. cloeziana plants (305.7 mg kg-1 resulting from a dose of 400 mg dm-3. The highest As accumulation was observed in E. grandis plants, which was confirmed as a species with potential for As phytoextraction, tending to accumulate As in the root system and stem.O arsênio (As tem sido considerado o poluente inorgânico de solo mais tóxico para os seres vivos, razão pela qual o interesse por espécies indicadoras e fitorremediadoras tem aumentado nos últimos anos. Particularmente para o Estado de Minas Gerais, que apresenta áreas remanescentes de atividade mineradora sujeitas à ocorrência de drenagem ácida, existe grande demanda por espécies com potencial para serem utilizadas na revegetação e "limpeza" de substratos contaminados por esse metaloide. Este

  10. Potential of macrophytes for removing atrazine from aqueous solution Potencial de macrófitas para remoção de atrazine de solução aquosa

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    F.P Guimarães

    2011-01-01

    Full Text Available The potential of three macrophytes, Azolla caroliniana, Salvinia minima, and Lemna gibba was assessed in this study to select plants for use in environmental remediation contaminated with atrazine. Experiments were carried out in a greenhouse over six days in pots containing Hoagland 0.25 strength nutritive solution at the following atrazine concentrations: 0; 0.01; 0.1; 1.0; 10.0 mg L-1. Decrease in biomass accumulation was observed in the three macrophytes, as well as toxic effects evidenced by the symptomatology developed by the plants which caused their deaths. The chlorosis and necrosis allowed to observe in the plants the high sensitivity of the three species to the herbicide. Plants presented low potential for removal of atrazine in solution when exposed to low concentrations of the herbicide. However, at the 10.0 mg L-1 atrazine concentration, L. gibba and A. caroliniana showed potential to remove the herbicide from the solution (0.016 and 0.018 mg atrazine per fresh mass gram, respectively. This fact likely resulted from the processes of atrazine adsorption by the dead material. The percentage of atrazine removed from the solution by the plants decreased when the plants were exposed to high concentrations of the pollutant. Azolla caroliniana, S. minima, and L. gibba were not effective in removing the herbicide from solution. The use of these species to remedy aquatic environments was shown to be limited.Avaliou-se, neste estudo, o potencial de três macrófitas - Azolla caroliniana, Salvinia minima e Lemna gibba - com vistas à seleção de plantas para remediação de ambientes contaminados por atrazine. Foram realizados experimentos em casa de vegetação durante seis dias, em vasos contendo solução nutritiva Hoagland (0,25 de força iônica, nas seguintes concentrações de atrazine: 0; 0,01; 0,1; 1,0; e 10,0 mg L-1. A redução da biomassa acumulada pelas macrófitas foi observada, bem como os efeitos de toxidez evidenciados pela

  11. Inhibition of cereal rust fungi by both class I and II defensins derived from the flowers of Nicotiana alata.

    Science.gov (United States)

    Dracatos, Peter M; van der Weerden, Nicole L; Carroll, Kate T; Johnson, Elizabeth D; Plummer, Kim M; Anderson, Marilyn A

    2014-01-01

    plants prior to the plants being inoculated with crown rust, they reduced the number of pustules per leaf area, as well as the amount of chlorosis induced by infection. Similar to observations in vitro, NaD1 was more effective as an antifungal control agent than NaD2. Further investigation revealed that both NaD1 and NaD2 permeabilized the plasma membranes of Puccinia spp. This study provides evidence that both secreted (NaD2) and nonsecreted (NaD1) defensins may be useful for broad-spectrum resistance to pathogens.

  12. Metabolic adaptations to ammonia-induced oxidative stress in leaves of the submerged macrophyte Vallisneria natans (Lour.) Hara.

    Science.gov (United States)

    Wang, Chao; Zhang, Song He; Wang, Pei Fang; Hou, Jun; Li, Wei; Zhang, Wen Jing

    2008-04-28

    Ammonia (i.e. the total of NH(3) and NH(4)(+)) has been one of the main causes of the decline of macrophytes in fresh water. In order to study the effects of ammonia toxicity, plants of the submersed macrophyte Vallisneria natans (Lour.) Hara were treated with various concentrations of NH(4)Cl (0.1, 0.4, 1.2, 2 and 2.8mM) for 4 days or with 2mM NH(4)Cl for different lengths of time (12h, 1, 2, 4 and 8 days). The toxic effect and oxidative stress caused by NH(4)Cl resulted in a reduction of total chlorophyll (chlorophyll a and b) and an increase in the levels of reactive oxygen species (ROS) O(2)(-) and H(2)O(2), with an increased concentration of NH(4)Cl and duration of exposure. Meanwhile, weak chlorosis and water-soaked symptoms were observed in older leaves exposed to 2.8mM NH(4)Cl for 4 days. The activity of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) was up-regulated in leaves treated with 1.2, 2 and 2.8mM NH(4)Cl for 4 days or with 2mM NH(4)Cl for 1, 2 and 4 days, when compared with controls. Among these enzymes, the activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase was significantly up-regulated in plants treated with 0.4mM NH(4)Cl for 4 days, while they were down-regulated at 4 and 8 days from their peak values in leaves treated with 2mM NH(4)Cl. The content of ascorbic acid decreased significantly in leaves treated with 0.4-2.8mM NH(4)Cl for 4 days or with 2mM NH(4)Cl for 2-8 days. The content of total glutathione (tGSH; reduced and oxidized glutathione) increased in leaves treated with NH(4)Cl at 0.4, 1.2 and 2mM for 4 days or with 2mM NH(4)Cl at 1, 2 and 4 days, while tGSH was decreased below the level of controls by treatment with 2.8mM NH(4)Cl for 4 days or to the level of controls by treatment with 2mM NH(4)Cl for 8 days. However, the content of malondialdehyde (MDA) decreased with increased concentration of NH(4)Cl and duration of

  13. RELACIÓN ENTRE ASOCIACIÓN MICORRÍCICA CON EL ESTADO FITOSANITARIO EN EL ARBOLADO URBANO DE BOGOTÁ D.C. RELATIONSHIP BETWEEN MYCORRHIZAL ASSOCIATION WITH THE STATE WOODY PLANT HEALTH IN THE CITY OF BOGOTA DC

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    CAROLINA RAMOS MONTAÑO

    . bogotensis had the opposite response. In general, dry environments favored the mycorrhizal infection levels. By considering overall data, there was a positive relation between the general phytosanitary status of the urban trees and the mycorrhizal colonization. The evaluation of the relationship with the incidence of specific foliar symptoms showed that chlorosis, bight and herbivory maintained a negative relation with the mycorrhization in E. myrtifolia and C. bogotensis. Results suggest that association with AM fungi helps in any way for reducing those symptoms, showing an important strategy to improve the sanity of urban trees.

  14. dsRNA介导的番木瓜环斑病毒(PRSV)的抗病性研究%Virus-resistance of Papaya Ringspot Virus Mediated by Double-Strand RNA

    Institute of Scientific and Technical Information of China (English)

    张帆; 姜玲

    2011-01-01

    Tobacco ( Nicotiana tabacum) , Arabidopsis thaliana, and host papaya( Carica papaya L. )of PRSV were used as model plant materials to testing whether RNAi could mediate resistance to papaya ringspot virus (PRSV). The agrobacterium was harbored with pHellsgate12-CPIR containing structured inverted sequences of the CP gene of PRSV,where were transformed into the tobacco and Arabidopsis. We also conducted an Agrobacterium-mediated transient expression experiment by infiltration in papaya. The three transgenic plants inoculated with PRSV were tested for resistance to PRSV. After PRSV challenge-inoculation for 3 to 7 days, leaves of the wild type plants displayed symptoms of necrosis, wrinkling and/or chlorosis, and the scale of the abnormal leaves in the transgenic plants was significantly lower than that of the wild type when the PRSV were inoculated in papaya and Arabidopsis separately.However, the difference in symptoms was not significant in transgenic tobacco and the control wild plant. We carried out a RT-PCR experiment on the three kinds of plants. The expression of CP mRNA was detected in the wild type plants infected with PRSV, but not in the transgenic plants. These results suggest that the transgenic plants may induce the RNAi process to resist PRSV.%以模式植物拟南芥(Arabidopsis thaliana)和烟草(Nicotiana tabacum)及PRSV寄主植物番木瓜(Carica papaya L.)作为试验材料,开展了番木瓜环斑病毒外壳蛋白基因dsRNA介导的PRSV病原抗性的研究.利用农杆菌介导法将番木瓜环斑病毒外壳蛋白CP基因反向重复表达载体pHellsgate12-CPIR(简称PHG12-CPIR)分别转化到烟草和拟南芥中,获得阳性植株,并利用渗透法和农杆菌介导的瞬时表达体系将pHG12-CPIR载体导入到番木瓜中.对转基因植株进行攻毒试验并分析了其抗病性.在接种3~7 d内,在拟南芥和番木瓜上转基因植株的发病情况较轻,而野生型植株叶片与转基因植株相比,均表现出不同

  15. In silico analysis of Mn transporters (NRAMP1) in various plant species.

    Science.gov (United States)

    Vatansever, Recep; Filiz, Ertugrul; Ozyigit, Ibrahim Ilker

    2016-03-01

    Manganese (Mn) is an essential micronutrient in plant life cycle. It may be involved in photosynthesis, carbohydrate and lipid biosynthesis, and oxidative stress protection. Mn deficiency inhibits the plant growth and development, and causes the various plant symptoms such as interveinal chlorosis and tissue necrosis. Despite its importance in plant life cycle, we still have limited knowledge about Mn transporters in many plant species. Therefore, this study aimed to identify and characterize high affinity Arabidopsis Mn root transporter NRAMP1 orthologs in 17 different plant species. Various in silico methods and digital gene expression data were used in identification and characterization of NRAMP1 homologs; physico-chemical properties of sequences were calculated, putative transmembrane domains (TMDs) and conserved motif signatures were determined, phylogenetic tree was constructed, 3D models and interactome map were generated, and gene expression data was analyzed. 49 NRAMP1 homologs were identified from proteome datasets of 17 plant species using AtNRAMP1 as query. Identified sequences were characterized with a NRAMP domain structure, 10-12 putative TMDs with cytosolic N- and C-terminuses, and 10-14 exons encoding a protein of 500-588 amino acids and 53.8-64.3 kDa molecular weight with basic characteristics. Consensus transport residues, GQSSTITGTYAGQY(/F)V(/I)MQGFLD(/E/N) between TMD-8 and 9 were identified in all sequences but putative N-linked glycosylation sites were not highly conserved. In phylogeny, NRAMP1 sequences demonstrated divergence in lower and higher plants as well as in monocots and dicots. Despite divergence of lower plant Physcomitrella patens in phylogeny, it showed similarity in superposed 3D models. Phylogenetic distribution of AtNRAMP1 and 6 homologs inferred a functional relationship to NRAMP6 sequences in Mn transport, while distribution of OsNRAMP1 and 5 homologs implicated an involvement of NRAMP1 sequences in Mn transport or a cross

  16. Ethylene inhibitor aminoethoxyvinilglycine on glomerella leaf spot in apple cultivar 'Royal Gala' Inibidor de etileno aminoetoxivinilglicina sobre a mancha foliar de 'Glomerella' na cultivar de macieira 'Royal Gala'

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    Amauri Bogo

    2011-06-01

    Full Text Available Aqueous solution of Aminoethoxyvinylglycine (AVG has been commercialized in Brazil as ReTainTM C, 15% mainly as a potent inhibitor of ethylene biosynthesis by prevention of pre-harvest abscission and ripening of apple fruits. The effect of the product was evaluated during the 2007-08 and 2008-09 crop seasons in edafoclimatic conditions of Santa Catarina upland. Plants of 'Royal Gala' cultivar were sprayed with ReTainTM C, four weeks before the first commercial harvest at doses of 0; 62,5; 125, and 250mg a.i L-1. The incidence and severity were quantified weekly in 100 leaves distributed in four branches with 12 replications and assessed the area under the incidence -I and severity -S disease progress curve (AUIDPC and AUSDPC of Glomerella leaf spot (GLS. The AUIDPC and AUSDPC were significantly higher after AVG application and although there was no significant difference between 125 and 250mg a.i L-1 doses in both 2007-08 and 2008-09 crop seasons. In general, the symptoms of GLS (e.g. chlorosis, necrosis increased between the fourth and eighth week after application.Solução aquosa de Aminoetoxivinilglicina (AVG tem sido comercializada no Brasil como ReTainTM C, 15%, principalmente como um potente inibidor da biossíntese do etileno na prevenção da abscisão e maturação de frutos em macieira. O efeito do produto foi avaliado durante as safras 2007-08 e 2008-09 nas condições edafo-climáticas do planalto Catarinense. Plantas de maçãs 'Royal Gala' foram pulverizadas com o ReTainTM C, quatro semanas antes da primeira colheita comercial, nas concentrações de 0;62,5; 125 e 250mg i.a L-1. A incidência e a severidade foram quantificadas semanalmente em 100 folhas, distribuídas em quatro ramos por plantas, com 12 repetições e calculado a área abaixo da curva do progresso da incidência -I e severidade -S da doença (AACPID e AACPSD. A AACPID e AACPSD foram significativamente maiores após a aplicação do AVG e não houve diferen

  17. Seletividade de cultivares de soja RR® submetidos a misturas em tanque de glyphosate + chlorimuron-ethyl associadas a óleo mineral e inseticidas selectivity of soybean RR® genotypes submitted to glyphosate + chlorimuron-ethyl tank mixtures associated to mineral oil and insecticides

    Directory of Open Access Journals (Sweden)

    C.D.G. Maciel

    2009-01-01

    mixtures combined with insecticides and adjuvants. Aiming to evaluate the selectivity of soybean RR® genotypes submitted to tank mixtures of the glyphosate formulations (Polaris®, Roundup Ready® and Roundup WG® with chlorimuron-ethyl (Classic®, and their associations with mineral oil (Joint Oil® and novaluron insecticides (Gallaxy 100 EC®, permethrin (Piredan® and methomyl (Lannate BR®, an experiment was conducted under field conditions at Maracai -São Paulo, during the 2006/2007 growing year. The experiment was arranged in a randomized complete block design with four replications, in a factorial scheme 16 x 4, with 16 representing the tank mixture associations of glyphosate formulations, mineral oil and insecticide, and the four genotypes Monsoy 7210RR®, Monsoy 7979RR®, BRS245RR® and CD 214RR®. Visual symptoms of initial intoxication in the genotypes studied were characterized by chlorosis and wrinkle in the leaves for all tank mixtures of glyphosate + chlorimuron-ethyl, associated or not with mineral oil, and novaluron, permethrin and methomyl insecticides .None of the tank mixtures promoted significant yield reductions for Monsoy 7210RR®, Monsoy 7979RR® and BRS245RR® genotypes, and controlled Ipomoea spp with satisfactory effectiveness, starting from 21 DAA (days after application.

  18. Cyanobacteria from the Baltic Sea and Finnish lakes as an energy source and modulators of bioenergetic pathways

    Energy Technology Data Exchange (ETDEWEB)

    Sumathy, S.

    2012-11-01

    . The extract from Nostoc XPORK 14A was the only one that modified the photosynthetic machinery and dark respiration. The compound responsible for this effect was identified, purified, and named M22. M22 demonstrated a dual-action mechanism: production of reactive oxygen species (ROS) under illumination and an unknown mechanism that also prevailed in the dark. During summer, the Baltic Sea is occupied by toxic blooms of Nodularia spumigena (hereafter referred to as N. spumigena), which produces a hepatotoxin called nodularin. Long-term exposure of the terrestrial plant spinach to nodularin was studied. Such treatment resulted in inhibition of growth and chlorosis of the leaves. Moreover, the activity and amount of mitochondrial electron transfer complexes increased in the leaves exposed to nodularin-containing extract, indicating upregulation of respiratory reactions, whereas no marked changes were detected in the structure or function of the photosynthetic machinery. Nodularin-exposed plants suffered from oxidative stress, evidenced by oxidative modifications of various proteins. Plants initiated strategies to combat the stress by increasing the levels of {alpha}-tocopherol, mitochondrial alternative oxidase (AOX), and mitochondrial ascorbate peroxidase (mAPX). (orig.)

  19. Exigências nutricionais da grápia ao fósforo e enxofre em Argissolo Vermelho distrófico arênico: efeito da adubação no crescimento Nutritional demand of grápia to phophorus and sulfur in paleaudalf soil: fertilization effects on growth

    Directory of Open Access Journals (Sweden)

    Evandro Luiz Missio

    2004-08-01

    conditions. Sixteen fertilization treatments were used in a complete bifactorial scheme (4x4, represented by the combination of four levels of P (0, 60, 120, and 180mg kg-1 and four levels of S (0, 10, 20, and 30mg kg-1. The plant growth in height, stem diameter, and number of leaves was analyzed monthly. After 130 days of cultivation other growth parameters were analyzed, as follow: number of fallen leaves, dry weight of roots, stem, leaves, and of the whole plant, and root/shoot dry weight ratio. The dry weight of the whole plant positively responded to the combination of phosphorus and sulfur fertilization, with the maximum technical efficiency level of 204 and 16mg kg-1 of soil, respectively. The phosphorus fertilization above 120mg kg-1 of soil gave rise a chlorosis in leaves similar to that of Fe deficiency. High availability of P in the soil was accounted for best growth of shoots in detriment of roots.

  20. 硝普钠对黄瓜幼苗缺镁和硝酸盐胁迫的缓解效应%Effects of sodium nitroprusside on alleviating magnesium deficiency of cucumber seedlings under NO-3 stress

    Institute of Scientific and Technical Information of China (English)

    杨全勇; 王秀峰; 韩宇睿; 杨静静; 魏珉; 杨凤娟; 史庆华; 李岩

    2015-01-01

    增加值、干物质增长量、幼苗根茎叶中镁离子含量、叶片光合色素含量、光合特性指标、叶绿素荧光、可溶性蛋白含量及抗氧化酶活性较未添加SNP处理的黄瓜幼苗显著提高,电解质渗漏率和丙二醛含量则明显降低。外施0.1 mmol/L SF则没有表现出明显的作用。【结论】硝酸盐胁迫下缺镁黄瓜幼苗生长受到明显抑制,出现失绿症状,通过添加0.1 mmol/L SNP ,黄瓜幼苗的生长抑制得到明显缓解,说明在硝酸盐胁迫下外源NO对缺镁黄瓜幼苗的胁迫有显著缓解作用,增强黄瓜幼苗的耐盐性和对镁的吸收能力。%[Objectives] Soils in the protected cultivation show serious secondary salinization, resulting in magnesium deficiency symptoms of plants. To explore effect of exogenous nitric oxide donor on alleviatingmagnesium deficiency under NO-3 stress in the experiment, the effect of exogenous nitric oxide donor ( sodium nitroprusside, SNP ) on growth of cucumber seedlings under magnesium deficiency was studied for providing a theoretical guidance to solving the problem of chlorosis of cucumber seedlings caused by magnesium deficiency.[Methods]The hydroponic method was used to cultivate cucumber seedlings, and seedlings with three real leaves were treated, and a basic nutrient solution was prepared according to the Yamazaki formula. The concentration of magnesium was designed as two levels, Mg2+ 2 mmol/L and Mg2+ 1 mmol/L, and the concentration of nitrate was designed as two levels, NO-3 14 mmol/L and NO-3 140 mmol/L. 0. 1 mmol/L SNP was applied to decrease the stress of magnesium deficiency and NO-3 stress on cucumber plants, and 0. 1 mmol/L SF( sodium ferricyanide) was used to observe influence of the SNP reaction products. The normal concentration of magnesium and nitrate treatment was set as control. NO-3 was provided by Ca(NO3)2·4H2O and KNO3(1 ∶1), and pH was adjusted by H2SO4 to keep at 5. 5-6. 5. [Results]1) The plant height

  1. Photosensitivity of Cucumber (Cucumis sativus L. Seedlings Exposed to Ultraviolet-B Radiation Fotosensibilidad de Plantines de Pepino de Ensalada (Cucumis sativus L. Expuestos a Radiación Ultravioleta del tipo B.

    Directory of Open Access Journals (Sweden)

    María Luisa Tapia F

    2010-03-01

    Full Text Available The intensity of ultraviolet-B radiation (UV-B has increased on the Earth´s surface due to the stratospheric ozone depletion, causing an adverse effect on a wide range of species, such as morphological, physiological, and biochemical alterations. This research studied the intraspecific photosensitivity of cucumber (Cucumis sativus L. seedlings exposed to UV-B. Six commercial cultivars were evaluated: Laura, Sprint 440, Dasher II, Exocet, Poinsett 76, and Marketmore 76 under greenhouse-controlled environmental conditions with a hydroponic sandwich-type system with a Hoagland II nutrient solution. Seedlings were irradiated from expanded cotyledons to the third true leaf with three intensities of UV-B radiation (30, 40, and 50 μW cm-2 for 18 d between 11:40-15:40 h. Seedling growth, morphology, accumulation of photosynthetic pigments, and absorbing UV-B pigments were evaluated. ‘Laura’ was the least affected by chlorosis and had a total absence of leaf curl, whereas ‘Poinsett 76’ was the most affected in the 40 and 50 μW cm-2 intensities. Both leaf area and seedling height of ‘Marketmore 76’ and ‘Poinsett 76’ had the lowest values. ‘Laura’ obtained the highest value in both fresh weight and dry weight. ‘Poinsett 76’ had the least amount of pigments absorbing UV-B and was 53% lower than that obtained by ‘Laura’. ‘Poinsett 76’ had lower chlorophyll and carotenoids. Parameters used were indicators of the seedling response to UV-B radiation, but could not be used for cucumber seedling sensitivity to UV-B radiation.La radiación ultravioleta tipo B (UV-B ha ido aumentando su intensidad a nivel de la superficie terrestre producto de la disminución del ozono estratosférico, provocando efectos negativos en una amplia gama de especies, observándose alteraciones morfológicas, fisiológicas y bioquímicas. En este trabajo se estudió la fotosensibilidad intraespecífica de plantines de pepino de ensalada (Cucumis sativus

  2. Effects of different pH values on seedling morphology and physiological characteristics of Vetiveria zizanioides under hydroponic culture%水培条件下不同 pH 值对香根草幼苗形态和生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    王青青; 周强; 於丙军

    2014-01-01

    part of leaf apexes with a little chlorosis and root morphology without obvious change except color under conditions of weak alkalinity ( pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0). With pH value of solution increasing ( alkalinity increasing) or decreasing (acidity increasing), both leaf water content and chlorophyll content decrease gradually and are lower than those of the control (pH 6. 5), while both relative electrolytic leakage and MDA content increase gradually and are higher than those of the control. In general, there are significant (P0. 05) difference in all indexes under conditions of weak alkalinity (pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0) with the control. With pH value of solution increasing ( alkalinity increasing ) or decreasing ( acidity increasing), both the maximum root length and root activity decrease gradually. Under conditions of weak alkalinity (pH 8. 0) and weak acidity (pH 5. 0), the maximum root length is slightly lower than that of the control and root activity is slightly higher than that of the control without significant difference. Under pH 9. 0-pH 11. 0 and pH 4. 0-pH 2. 0, both the maximum root length and root activity are significantly lower than those of the control, in which root length is the shortest and root activity is the smallest under pH 11. 0, with 60. 50% and 9. 52% of the control,respectively. It is suggested that V. zizanioides has a wide adaptation range to acidity-alkalinity of soil, and can adapt soil habitat with pH 4. 0-pH 9. 0.

  3. Tolerância de diferentes cultivares de cana-de-açúcar (Saccharum spp. A herbicidas Tolerance of different sugarcane (Saccharum spp. Cultivars to herbicides

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    F.S Zera

    2011-09-01

    . The cultivars were allocated to the plots and the herbicides to the sub-plots (five 8.0 m long rows and 1.5 m spacing, with 4 repetitions. The herbicides sulfentrazone (0.8 kg ha-1, imazapic (0.147 kg ha-1, isoxaflutole (0.1125 kg ha-1, clomazone (1.1 kg ha-1, ametryn (1.463 kg ha-1 + trifloxysulfuron sodium (0.037 kg ha-1 and control were evaluated on 3-yr-old ratoons of the cultivars IACSP94-2094, IACSP94-2101, IACSP93-3046, IACSP94-4004, IAC86-2480 and RB72454 in post emergence. The traits evaluated were: plant toxicity symptoms in the plant leaves; total chlorophyll content and photochemical efficiency (Fv/Fm at 15, 30 and 60 days after application (DAA; height (cm at 30 and 270 DAA, and plant stand (stalk m-1 at 30 and 180 DAA. Diameter (cm, estimated productivity (t ha-1 and quality analysis were evaluated at 270 DAA. The sugarcane cultivars IACSP94-2094, IACSP93-3046, IACSP94-4004, IAC86-2480, RB72454, and IACSP94-2101 especially, were susceptible to clomazone up to 30 DAA, due to leaf chlorosis and lower chlorophyll content, but had no effect on quality characteristics and productivity. The cultivars were also tolerant to other herbicides.

  4. ASİDİK YAGIŞLARIN TRİTİCUM VULGARE ( BUGDAY ve ZEA • • • • • MA YS SACCHARA TA (MISIR BITKILERINE ETKILERI

    Directory of Open Access Journals (Sweden)

    NEVİN YALÇIN

    1999-12-01

    Full Text Available Bu çalışmada, asidik yağışların Triticum Vulgare (Buğday ve Zea Mays Saccbarata ( Mısır bitkile rine et ki leri incel enmiştir. Bu a1naçla, 24 adet 20x20x30 cn1 boyutundaki teneke saksı lara ekilen tohumlar pH 1 � 2, 3, 4. 5, 6 olan HN03 ve H2S04 ç özel til e ri ile bir ay bo yunc a sulanmışlar dır.T. Vulgar e ve Z.M. Saccharata yap r a k lar ı n d a k loroz i s (sa r arma ve flecking (benekleşme görülmüştür.Büyüme, 15. g ünde n sonra durınuştur. pH s ı düşük olan çö zel t i l er ile sulanan bitkilerde boyca enge llennıe görülmüş, çürüme daha önce b aş ! an1ış tı r . Ayrıca as i di k çöz elti lerl e sulamanın tohum çim l e n m es i ni gec i ktirdi ğ i gözlenıniştir. Biyomas değ e r lerinde de k ayıpla r kaydedilıniştir. Düşük pH derecelerinde ka yıp l arı n daha fazla olduğu b eli r le nnı i ş t ir. Her iki bit k inin kök ve gövdelerinin anatemisinde bir bozulına görülmeıniştir. ABSTRACT In this study, the effects of acid rains on Triticum Vu l g a re (\\Vheat and Zea Mays Saccharata (Com were investigated. For this purpose, seeds were sowed to 24 tin pots at diı n ensions of 20x20x30 cm and they were vvatered with HN03 and H2S04 solutions which to be pH L 2, 3, 4, 5, 6 for o ne month. T.Vulgare and Z.M. Saccharata leavcs showed chlorosis and flecking. The growing stopped after 15 days. At solutions with low pH, p I ant l e ngt h s w ere n1easured shorter and rotting w as begun earlier than otlıers. It also inhibited seed gennination by de lay ing the same. The bi o mass values alsa s h owe d a loss and this was the h i g hest at the low pH degree s . The root and stern defo rmat i ons in each the two s p c ci es were not seemed . I. GİRİŞ Atmosferin kirl errmesi sonucu rneydana gelen asit yağmurlar1 veya asit ç ö k e J n 1 es i sanayinin, termik santr allerin , ulaşun araçlan n ın ve fosil yakıtların yaydığı SOx , kükürt oksit ve NOx , azot oksit

  5. Apple Rootstock New Variety Chistock #1%苹果砧木新品种中砧1号

    Institute of Scientific and Technical Information of China (English)

    韩振海; 王忆; 张新忠; 许雪峰; 孙扬吾; 沈隽

    2013-01-01

    The iron has a very important role in the growth and development of the plant,iron deficiency causes chlorosis in apple trees.The main producing areas of apple in China just iron deficiency,therefore,filter out iron-efficient resources from rich apple germplasm resources,and breeding new varieties of apple rootstocks through breeding means is fundamental pathway to solve due to iron deficiency affected yield and quality of apple production.Since 1984,the project team screened iron-efficient genotypes from 40 apple stocks and found Malus xiaojinensis Cheng et Jiang,grow normally and do not exhibit symptoms of chlorosisin in conditions of very low Fe content,was considered to be an excellent germplasm with tolerance to iron deficiency.Subsequently,open pollinated hybrids groups were established on the basis of M.xiaojinensis Cheng et Jiang seedlings.In 1990,excellent grades was obtained through original selection from natural seedlings.Then after multiple selection and comparison test,bred apple clonal rootstocks Chistock #1.Chistock #1 is a tetraploid in chromosome number (2n =4x =68),with a capacity of apomixis,and setting rate above 85% after emasculation bagged.Then with excellent grafting compatibility,seedling dry good standing and strong solid ground,semi-dwarf,dwarf extent,effects and yield capacity were similar with simi-dwarfing apple rootstock M7.Sweet fruit flavor,palatability,and excellent quality.Resist apple early defoliation disease and branches ring rot,high resistance to apple Chlorotic leaf spot virus(CLSV),Stem pitting virus(SPV) and the Stem groove virus(SGV) and other latent virus.Chistock #1 can effectively prevent etiolation due to iron deficiency as apple rootstock in the lime parent material soil areas.%铁是植物生长的必需微量元素,缺铁导致苹果发生失绿症,生长结果受到影响.我国苹果主产区恰在缺铁区域范围内,因此,从丰富的苹果种质资源中筛选出铁高效型资源,通

  6. Lead accumulation and tolerance of Moso bamboo (Phyllostachys pubescens) seedlings:applications of phytoremediation%植物修复的应用:毛竹苗对铅的积累与耐性研究

    Institute of Scientific and Technical Information of China (English)

    Dan LIU; Song LI; Ejazul ISLAM; Jun-ren CHEN; Jia-sen WU; Zheng-qian YE; Dan-li PENG; Wen-bo YAN; Kou-ping LU

    2015-01-01

    A hydroponics experiment was aimed at identifying the lead (Pb) tolerance and phytoremediation potential of Moso bamboo (Phyl ostachys pubescens) seedlings grown under different Pb treatments. Experimental results indicated that at the highest Pb concentration (400 μmol/L), the growth of bamboo seedlings was inhibited and Pb concentrations in leaves, stems, and roots reached the maximum of 148.8, 482.2, and 4282.8 mg/kg, respectively. Scanning electron microscopy revealed that the excessive Pb caused decreased stomatal opening, formation of abundant inclusions in roots, and just a few inclusions in stems. The ultrastructural analysis using transmission elec-tron microscopy revealed that the addition of excessive Pb caused abnormal y shaped chloroplasts, disappearance of endoplasmic reticulum, shrinkage of nucleus and nucleolus, and loss of thylakoid membranes. Although ultrastructural analysis revealed some internal damage, even the plants exposed to 400 µmol/L Pb survived and no visual Pb toxicity symptoms such as necrosis and chlorosis were observed in these plants. Even at the highest Pb treatment, no sig-nificant difference was observed for the dry weight of stem compared with controls. It is suggested that use of Moso bamboo as an experimental material provides a new perspective for remediation of heavy metal contaminated soil owing to its high metal tolerance and greater biomass.%目的:探索毛竹在修复铅污染土壤的植物修复潜力。  创新点:使用了毛竹作为一种全新的植物修复材料进行研究。得到了毛竹幼苗在铅胁迫下的生长与生理反应情况,不同植物组织对铅的吸收与积累情况,铅胁迫下毛竹幼苗表层与细胞超微结构的特征。  方法:根系形态分析(图3)、植物重金属含量分析(表1)、扫描电镜分析(图4)和透射电镜分析(图5)。  结论:各组织部位铅浓度的值揭示了,毛竹是一个很好的固定铅污染土

  7. Potential of macrophyte for removing arsenic from aqueous solution Potencial de remoção de arsênio de solução aquosa por macrofita

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    F.P. Guimaraes

    2012-12-01

    Full Text Available The potential of three aquatic macrophytes, Azoll caroliniana, Salvinia minima and Lemna gibba, was evaluated in this work aimed at selection of plants to be used in remediation of environments contaminated by arsenic (As. The experiments were carried out in a greenhouse during six days in pots containing Hoagland solution (¼ ionic strength at As concentrations of 0.5; 2.5 and 5.0 mg L-1. The three species showed greater As accumulation as the concentration of the metalloid in solution increased. However, a reduction was detected in fresh and dry mass gain when the plants were exposed to high As concentrations. The macrophytes showed differences in efficiency of removal of As in solution. A. caroliniana, S. minima and L. gibba accumulated, on average, 0.130; 0.200; and 1.397 mg mDM-1, respectively, when exposed to 5.0 mg L-1 of As. The macrophytes absorbed a greater quantity of As in solution with low phosphate content. The greater As concentration in L. gibba tissues lowered the chlorophyll and carotenoid contents as shown by the high chlorosis incidence. Lemna gibba also exhibited a decrease in leaf size, with the total chlorophyll and carotenoid synthesis not being affected by As in A. caroliniana. This species exhibited purplish leaves with high concentration of anthocyanin, whose presence suggested association to phosphate deficiency. Marginal necrosis occurred on S. minima floating leaves, with the released daughter-plants not showing any visual symptoms during the treatment. The percentage of As removed from the solution decreased when the plants were exposed to high concentrations of the pollutant. Among the three species studied, only L. gibba could be considered an As hyper-accumulator. The use of this plant species for remediation of aquatic environments was shown to be limited and requires further investigation.O potencial de três macrófitas aquáticas - Azolla caroliniana, Salvinia mínima e Lemna gibba - foi avaliado neste

  8. 水培条件下不同 pH 值对香根草幼苗形态和生理特性的影响%Effects of different pH values on seedling morphology and physiological characteristics of Vetiveria zizanioides under hydroponic culture

    Institute of Scientific and Technical Information of China (English)

    王青青; 周强; 於丙军

    2014-01-01

    part of leaf apexes with a little chlorosis and root morphology without obvious change except color under conditions of weak alkalinity ( pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0). With pH value of solution increasing ( alkalinity increasing) or decreasing (acidity increasing), both leaf water content and chlorophyll content decrease gradually and are lower than those of the control (pH 6. 5), while both relative electrolytic leakage and MDA content increase gradually and are higher than those of the control. In general, there are significant (P0. 05) difference in all indexes under conditions of weak alkalinity (pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0) with the control. With pH value of solution increasing ( alkalinity increasing ) or decreasing ( acidity increasing), both the maximum root length and root activity decrease gradually. Under conditions of weak alkalinity (pH 8. 0) and weak acidity (pH 5. 0), the maximum root length is slightly lower than that of the control and root activity is slightly higher than that of the control without significant difference. Under pH 9. 0-pH 11. 0 and pH 4. 0-pH 2. 0, both the maximum root length and root activity are significantly lower than those of the control, in which root length is the shortest and root activity is the smallest under pH 11. 0, with 60. 50% and 9. 52% of the control,respectively. It is suggested that V. zizanioides has a wide adaptation range to acidity-alkalinity of soil, and can adapt soil habitat with pH 4. 0-pH 9. 0.

  9. Effects of compound amino acid-iron fertilizer on fruit quality of kiwi fruit%喷施复合氨基酸铁肥对猕猴桃果实品质的影响

    Institute of Scientific and Technical Information of China (English)

    车金鑫; 蔡俊卿; 翟丙年; 郑小春; 卢海蛟; 赵政阳

    2011-01-01

    【Objective】 The effect of compound amino acid-Iron Fertilizer on iron content of kiwi fruit leaves,fruit quality and yield was investigated to screen the best spraying concentration of compound amino acid-Iron Complex Fertilizer which can be used in the fruit quality enhancement and the prevention and treatment of chlorosis.【Method】 5-year-old 'Qinmei' kiwifruit was used as test cultivar and the group which was sprayed clear water was used as control.Field experiment was conducted to study the effects of different concentrations of Compound amino acid-Iron Fertilizer(diluted 1 500,1 000,500 times) on kiwi fruit quality by determining the iron content of kiwi fruit leaves as well as the content of reducing sugar,titratable acid,vitamin C and iron in kiwi fruit and fruit yield in calcareous soil.【Result】 The results showed that spraying different concentrations of compound amino acid-iron fertilizer could significantly increase the iron content of etiolated kiwifruit leaves.Titratable acid in fruit first increased and then decreased with the increase of the concentration of compound amino acid-iron fertilizer.When compound amino acid-iron fertilizer(diluted 1 000 times) was sprayed,the fruit content of vitamin C,soluble solids and reducing sugar were the highest,the flavor was the best and the titratable acid was the lowest;When compound amino acid-iron fertilizer(diluted 500 times) was sprayed,the fruit iron content could be best increased.Compared with the control,spraying compound amino acid-iron fertilizer had no obvious effect on fruit yield.【Conclusion】 Considering the effects,the best concentration is 1 000 times of the compound amino acid-iron fertilizer on kiwi fruit quality under calcareous soil conditions.%【目的】研究喷施复合氨基酸铁肥对猕猴桃叶片铁含量及果实品质和产量的影响,筛选用于猕猴桃缺铁黄化病防治及果实品质提高的复合氨基酸铁肥的最佳喷施浓度

  10. CHEMICAL CONTROL OF ACARID Brevipalpus phoenicis (Geijskes, 1939 (Acari-Tenuipalpidae, TRANSMITTER OF LEPROSIS IN CITRUS CONTROLE QUÍMICO DO ÁCARO Brevipalpus phoenicis (Geijskes, 1939 (Acari-Tenuipalpidae, TRANSMISSOR DA LEPROSE EM CITROS

    Directory of Open Access Journals (Sweden)

    saúl Edgard Mendez Sanchez

    2007-09-01

    Full Text Available

    Leprosis of citrus is becoming a serious problem for a nascent citriculture of Goiás State, for this disease provokes defoliation and sometimes even death of young ‘Pera’ plants in forming orchard. This experiment was developed in one property with a forming orchard, located in the municipality of Leopoldo de Bulhões - Goiás. The prescribed treatments, expressed in dose per plant, of commercial product were: 1 binapacril (Acricid 40 CE, 16 ml; 2 clofentezine (Acaristop 50 SC, 2.0 ml; 3 clofentezine (Acaristop 50 SC, 3.0 ml; 4 tefluron + binapacril (Nomolt + Acricid 40 CE - 1.2 and 5.0 ml; 5 cyhexatin (Plictran 50 BR, 3.2 ml; 6 avermectin + triona (Vertirnec 18 CE + Triona B, 3.0 ml and 25 ml, respectively; 7 control. These treatments were realized in two stages. In the first, were ministered only acarid-killers; in the second, it was added foliar fertilization with formula 20-36-20, containing more Mg, S, B, Zn, Fe, Mn, Mo and Co, at dose of 10 g fertilizer/plant. Estimations were realized before and at 7, 15 and 30 days after pulverization, obtaining at 7 days the best results with treatments 3, 4, 5 and 6 with 77.95%, 77.20%, 78.11% and 80.31% of control, respectively, although it had none statistic significance. At 15 and 30 days all treatments presented results up to 75% of control. It is accentuated that in treatments 5 and 6 of the stage that received foliar fertilization the plants recovered from chlorosis with greater rapidity, when confronted with other treatments.

    A leprose dos citros está se tomando problema sério para a nascente citricultura causando desfolhamento e às vezes até a morte das plantas jovens de pomares em formação. Visando ao controle do ácaro da leprose Brevipalpus phoenicis (Geijskes, 1939, o experimento foi realizado em uma propriedade com pomar em formação da

  11. Efeito do metribuzin no controle das plantas daninhas e na produção de grãos em Glycine max (L merrill Effect of metribuzin in weed control and yield of Glycine max (L. merrill

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    J. P. Silva Neto

    1991-01-01

    field conditions in a clayey red yellow podzolic soil with 2,9% organic matter at Viçosa, MG, during the 1985 /86 growing season. Most of the monocotyledqns species present in the experimental area consisted of Cyperus rotundus L., Brachiaria plantaginea (Link Hitch and Cynodon dactylon (L. Pers. Reduction observed was only for Brachiaria plantaginea as metribuzin doses increased, the sa me occuring with dycot iledons species existent in the area except for Oxalis oxypt era Prop. wich was not controlled by the doses using. The avera ge of the tota l weed density minus Cyper us rotundus, Oxalis oxyptera and Cynodon da+-ylon was 141, 124, 62 and 59 plants.m² for 0,0; 0,35; 0,70 and 1,05 kg a.i.ha-1 metribuzin, respectively. The lowest dose of metri buzin (0,35 kg a.i.ha-1 was as sufficient to promote reduction on weed shoot biomass at the highest did (1,05 kg a.i.ha-1. However, the mean of the total weed density was drastically recuded in the doses of 0,70 and 1,05 kg a.i.ha-1. The metribuzin caused damage to soybean plants at highest dose (1,05 kg a.i.ha-1 employed with a slight leaf injury '(chlorosis until 25 days after emergence. After this period it was observed a total recovery of the plants treat ed with this dose. The yield and the harvest index were not affected by doses of metribuzin.

  12. Crescimento e morfoanatomia foliar de eucalipto sob efeito de deriva do glyphosate Leaf growth and morphoanatomy of eucalypt under the effect of glyphosate drift

    Directory of Open Access Journals (Sweden)

    L.D. Tuffi Santos

    2005-03-01

    -se aumento na espessura do limbo e do PPA submetidos a 345,6 g e.a. ha¹ de glyphosate, enquanto o PLA e a EAD demonstraram acréscimo na espessura somente aos 15 DAA sob a mesma dosagem. As doses de 172,8 e 345,6 g e.a. ha-1 de glyphosate promoveram aumento na espessura do limbo e do PPA aos 15 DAA. O aumento na espessura do limbo é resultante da expansão das células do parênquima paliçádico, podendo estar relacionado à resposta das plantas à perda de área foliar específica, bem como à síntese de compostos secundários, como celulases, provocados pela ação do glyphosate.The effects of glyphosate drift during application are harmful to the eucalypt culture. This work evaluated the effects of simulated glyphosate drift on leaf growth and morphoanatomy of the clone 15-CENIBRA (Eucalyptus urophylla X E. grandis. A randomized block design was used with four replications. Each experimental plot was represented by one plant cultivated in a 10 liter pot with soil. The treatments were 0; 43.2; 86.4; 172.8 and 34.6 g a.e. ha-1 of glyphosate, applied 40 days after seedling planting with a precision sprayer, so that the upper third of the plants was unaffected. The morphological alterations in the plant shoot were described .Intoxication percentage in relation to the control was evaluated 7, 15, and 30 days after application (DAA. Leaves were collected from the third node of the first basal branch of the plants, fixed in FAA50 and stored in 70% ethanol 7 and 15 DAA. Cross section of the intermediate region was stained with astra blue and basic fuchsia and installed on permanent slides to measure thickness, of the palisade (PPA and spongy (PLA parenchyma, epidermis of the adaxial (EAD and abaxial (EAB sides, as well as the proportion of each tissue area using software "Image-Pro Plus". From the 5th DAA, leaf wilt, chlorosis and curling were observed in the plant apices sprayed with 17.8 and 345.6 g a.e. ha¹ of glyphosate. The plants subjected to 24% of the rate attained

  13. Responses of ascorbate-glutathione cycle and glutathione metabolism to cadmium stress in Salix matsudana Koidz seedlings%旱柳幼苗抗坏血酸谷胱甘肽循环及谷胱甘肽代谢对镉胁迫的响应

    Institute of Scientific and Technical Information of China (English)

    杨卫东; 李廷强; 丁哲利; 杨肖娥

    2014-01-01

    Summary Cadmium (Cd) is released into environment due to anthropogenic activities, resulting in great environmental problems.As a no-essential element,Cd displays high toxic to plants,resulting in leaf chlorosis, root necrosis,inhibition of photosynthesis,and disorder of water and nutrient metabolism.Simultaneously,Cd stress induces the generation of reactive oxygen species (ROS).Plants have evolved many strategies to avoid Cd stress.The ascorbate-glutathione (AsA-GSH) cycle and glutathione metabolism involve in scavenging of ROS to prevent the accumulation of the strong oxidant H2 O2 . The AsA-GSH cycle contains four non-enzymatic antioxidants and four different enzymes,i.e.,ascorbate(AsA),dehydroascorbate(DHA)and reduced glutathione (GSH),oxidized glutathione(GSSG),ascorbate peroxidase(APX),monodehydroascorbate reductase(MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR).AsA-GSH cycle plays a pivotal role in counteracting Cd toxicity.Glutathione metabolism coupled with glutathione peroxidase (GPX) and glutathione S-transferase (GST) also plays a key role in Cd tolerance and detoxification. In the last decade,willows (Salix spp.) have showed large phytoremediation potential for heavy metals,and were considered as high Cd accumulators than other plants.Salix matsudana Koidz is mainly distributed in China, which is widely planted in flood-prone lands,showing great potential in phytoremediation of Cd.But compared with hyperaccumulators and other herbaceous plants,the tolerance and detoxification of Cd in willows have been poorly understood.In the present study,we aimed to investigate the AsA-GSH cycle and GSH metabolism of S. matsudana in response to Cd stress. Seedlings of S.matsudanas were mounted on Styrofoam and were grown in a hydroponic culture.After pre-gown for 60 days,seedlings with uniform size were selected and treated with different Cd doses(0,5 and 25μmol/L) for 28 d.Antioxidants (AsA,DHA,GSH,and GSSG) and related enzymes