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Sample records for chlorosis

  1. Precision phenotyping of imidazolinone-induced chlorosis in sunflower.

    Science.gov (United States)

    Ochogavía, Ana Claudia; Gil, Mercedes; Picardi, Liliana; Nestares, Graciela

    2014-12-01

    Chlorosis level is a useful parameter to assess imidazolinone resistance in sunflower (Helianthus annuus L.). The aim of this study was to quantify chlorosis through two different methods in sunflower plantlets treated with imazapyr. The genotypes used in this study were two inbred lines reported to be different in their resistance to imidazolinones. Chlorosis was evaluated by spectrophotometrical quantification of photosynthetic leaf pigments and by a bioinformatics-based color analysis. A protocol for pigment extraction was presented which improved pigment stability. Chlorophyll amount decreased significantly when both genotypes were treated with 10 μM of imazapyr. Leaf color was characterized using Tomato Analyzer(®) color test software. A significant positive correlation between color reduction and chlorophyll concentration was found. It suggests that leaf color measurement could be an accurate method to estimate chlorosis and infer chlorophyll levels in sunflower plants. These results highlight a strong relationship between imidazolinone-induced chlorosis and variations in leaf color and in chlorophyll concentration. Both methods are quantitative, rapid, simple, and reproducible. Thus, they could be useful tools for phenotyping and screening large number of plants when breeding for imidazolinone resistance in this species. PMID:25914598

  2. 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...

  3. GRAPEVINE Fe-CHLOROSIS ON PODUNAVLJE VINEGROWING AREA

    OpenAIRE

    Mato Drenjančević

    2012-01-01

    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 ...

  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. 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

  6. 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...

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

    Science.gov (United States)

    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

  9. First report of Tomato chlorosis virus infecting sweet pepper in Costa Rica

    Science.gov (United States)

    In September 2008, a survey of whiteflies and whitefly-borne viruses was performed in greenhouses in the province of Cartago, Costa Rica. During this survey, sweet pepper (Capsicum annuum cv. Nataly) plants showing interveinal chlorosis, enations, necrosis, and mild upward leaf curling were observed...

  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. PMID:26370789

  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. 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

  16. 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.

  17. 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.

  18. Microarray analysis of iron deficiency chlorosis in near-isogenic soybean lines

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    Cianzio Silvia R

    2007-12-01

    Full Text Available Abstract Background Iron is one of fourteen mineral elements required for proper plant growth and development of soybean (Glycine max L. Merr.. Soybeans grown on calcareous soils, which are prevalent in the upper Midwest of the United States, often exhibit symptoms indicative of iron deficiency chlorosis (IDC. Yield loss has a positive linear correlation with increasing severity of chlorotic symptoms. As soybean is an important agronomic crop, it is essential to understand the genetics and physiology of traits affecting plant yield. Soybean cultivars vary greatly in their ability to respond successfully to iron deficiency stress. Microarray analyses permit the identification of genes and physiological processes involved in soybean's response to iron stress. Results RNA isolated from the roots of two near isogenic lines, which differ in iron efficiency, PI 548533 (Clark; iron efficient and PI 547430 (IsoClark; iron inefficient, were compared on a spotted microarray slide containing 9,728 cDNAs from root specific EST libraries. A comparison of RNA transcripts isolated from plants grown under iron limiting hydroponic conditions for two weeks revealed 43 genes as differentially expressed. A single linkage clustering analysis of these 43 genes showed 57% of them possessed high sequence similarity to known stress induced genes. A control experiment comparing plants grown under adequate iron hydroponic conditions showed no differences in gene expression between the two near isogenic lines. Expression levels of a subset of the differentially expressed genes were also compared by real time reverse transcriptase PCR (RT-PCR. The RT-PCR experiments confirmed differential expression between the iron efficient and iron inefficient plants for 9 of 10 randomly chosen genes examined. To gain further insight into the iron physiological status of the plants, the root iron reductase activity was measured in both iron efficient and inefficient genotypes for plants

  19. 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

    2016-03-23

    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

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

    Science.gov (United States)

    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

  1. 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.

  2. Peach latent mosaic viroid variants inducing peach calico (extreme chlorosis) contain a characteristic insertion that is responsible for this symptomatology

    International Nuclear Information System (INIS)

    The involvement of Peach latent mosaic viroid (PLMVd) in an extensive chlorosis of peach known as calico (PC) has been advanced but ultimate proof is lacking. Sequencing of 16 full-length PLMVd cDNA clones of a PC isolate revealed two groups of variants. Nine had a size (336-338 nt) similar to that of typical PLMVd variants of nonsymptomatic and mosaic-inducing isolates, whereas the other 7 were longer (348-351 nt) due to an insertion of 12-13 nt. This insertion was always found in the hairpin loop capping the hammerhead arm, had a limited sequence variability, and folded itself into a hairpin. When three PLMVd dimeric transcripts, two with and the other without the insertion, were slash-inoculated on GF-305 peach seedlings, PC symptoms were produced exclusively by the RNAs containing the insertion, which was conserved in the progeny. These data demonstrate that the agent of PC is PLMVd. Direct support that the 12- to 13-nt insertion contains the PC pathogenicity determinant was obtained by its removal through site-directed mutagenesis from one of the PC-inducing variants. Inoculations with dimeric transcripts of the resulting variant showed that it could replicate but without eliciting symptoms. Our results also suggest that the insertion emerges sporadically de novo

  3. 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

  4. Complete nucleotide sequence of capsicum chlorosis virus isolated from Phalaenopsis orchid and the prediction of the unexplored genetic information of tospoviruses.

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    Zheng, You-Xiu; Chen, Ching-Chung; Jan, Fuh-Jyh

    2011-03-01

    Phalaenopsis orchids are popular ornamentals all over the world. A tospovirus, capsicum chlorosis virus (CaCV-Ph) had been identified as the cause of chlorotic ringspots on leaves of Phalaenopsis orchids in Taiwan. The tripartite genome of CaCV-Ph was found to contain 3608, 4848 and 8916 nt of S, M and L RNAs, respectively. Phylogenetic analysis of the nucleocapsid (N) protein confirmed that CaCV-Ph is a member of the watermelon silver mottle virus (WSMoV) serogroup in the genus Tospovirus. Based on the relations among the nonstructural protein (NSs), glycoprotein (GnGc), thrips genera, host and geographical distribution, tospoviruses and thrips could be classified into two major types: WSMoV-Thrips-Asian and Tomato spotted wilt virus (TSWV)-Frankliniella-EuroAmerican. The proline (P(459)) of all tospoviral Gn proteins was indispensable for thrips transmission, but the RGD motif, which is maintained by only six tospoviruses, may not be required for thrips transmission. An RdRp catalytic domain found in the conserved region of the L protein may recognize the typically conserved sequences on the 5' and 3' terminal regions (5' AGAGCAAU 3'). PMID:21161553

  5. 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...

  6. 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

  7. Comportamento sazonal da clorose variegada dos citros em três regiões do Estado de São Paulo Seasonal behaviour of citrus variegated chlorosis in three regions of São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Francisco F. Laranjeira

    2003-12-01

    Full Text Available Caracterizou-se a evolução de variáveis relacionadas à clorose variegada dos citros em plantas de três regiões do Estado de São Paulo (Noroeste, Centro e Sul, visando determinar diferenças no padrão sazonal do patógeno, dos vetores, do hospedeiro e da doença. Foram avaliadas mensalmente 20 plantas sintomáticas em talhões de laranja (Citrus sinensis 'Pêra' enxertada em limão (Citrus limonia 'Cravo', em três regiões do Estado de São Paulo, no período de dezembro de 1998 a dezembro de 2000, utilizando-se as seguintes variáveis: número de brotações novas (bn; percentagem de ramos sintomáticos (prs; percentagem de ramos assintomáticos infetados (prai; percentagem total de ramos infetados (ptri e estimativa de concentração bacteriana (ecb. Em cada região foram obtidas as variáveis temperatura mínima, temperatura máxima, precipitação pluviométrica e número de cigarrinhas capturadas em armadilha amarela. Para a determinação de correlação entre variáveis, utilizou-se a análise de Lags Distribuídos e para a comparação de regiões e estações do ano, a análise de Kruskal-Wallis, Friedman e o teste de Nemenyi (pThis work was to characterize the evolution of Citrus variegated chlorosis (CVC related variables in plants of three regions in the State of São Paulo (Northeast, Center and South, in order to demonstrate differences in seasonal pattern of the pathogen, Xylella fastidiosa, vectors (sharpshooters, host [sweet orange (Citrus sinensis 'Pera' grafted on Rangpur lime (Citrus limonia] and disease. Twenty symptomatic plants were evaluated monthly from December 1998 to December 2000. The following variables were measured: number of new flushes (nf, percentage of symptomatic branches (psb, percentage of infected assymptomatic branches (piab, percentage of infected branches (pib, estimation of bacteria concentration (ebc, lower and higher temperatures, rain fall and number of sharpshooters in yellow traps. The

  8. 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

  9. Efecto de la clorosis férrica en el tamño y la concentración de aceite en el fruto del palto (Persea americana Mill. Effect of iron chlorosis on avocado (Persea americana Mill. fruit size and oil concentration

    Directory of Open Access Journals (Sweden)

    Bruno Razeto

    2005-03-01

    Full Text Available Con el objetivo de determinar en qué medida la clorosis férrica influye en el tamaño y el contenido de aceite en el fruto de palto (Persea americana Mill. se realizó un estudio en un huerto de 22 años cv. Hass, ubicado en Quillota, Chile (32º51’ lat. Sur, 71º6’long. Oeste. Se seleccionaron 12 árboles con distinto grado de clorosis férrica, desde algunos con follaje verde normal hasta otros severamente cloróticos. Con fecha 30 de agosto se colectaron 15 frutos y 30 hojas por árbol. En estas muestras se determinó la concentración de hierro mediante espectrofotometría. En la piel del fruto y en las hojas se midió color con colorímetro triestímulo y concentración de clorofila mediante extracción con etanol y medición de absorbancia en espectrofotómetro. También se determinó el peso del fruto y la concentración de aceite en la pulpa mediante extracción con éter de petróleo. El fruto de los árboles normales presentó una concentración de hierro de 13,8 mg kg-1 (P In order to determine the effect of iron chlorosis on fruit size and oil content, of avocado (Persea americana Mill. a trial was conducted on a 22-year-old orchard cv. Hass located at Quillota, Chile (32º51’ S lat., 71º6’ W long.. Twelve trees with different degrees of iron chlorosis were selected, normal green foliage and others highly chlorotic. Fifteen fruit and 30 leaves per tree were taken on August 30. In this samples iron concentration was determined by spectrophotometry. Color by tri-stimulus colorimetry and chlorophyll concentration by ethanol extraction and spectrophotometer absorbance were measured on leaves and fruit peels. Fruit weight and oil content were measured by petroleum ether extraction. Fruit from normal trees had an iron concentration of 13.8 mg kg-1 (P <= 0,05 higher than that of chlorotic trees. A high correlation between the chlorophyll level of leaves and fruit peels was found (R² = 0.74. The leaf chlorophyll concentration was

  10. 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

  11. 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

  12. 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

  13. 76 FR 8603 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Science.gov (United States)

    2011-02-15

    ... FR 17289-17295 on April 6, 2010. FOR FURTHER INFORMATION CONTACT: Dr. Arnold Tschanz, Senior Plant... and published in the Federal Register on April 6, 2010 (75 FR 17289-17295, Docket No. APHIS-2008- 0052... for HLB and that was published in the Federal Register and effective on June 17, 2010 (75 FR...

  14. 75 FR 17289 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Science.gov (United States)

    2010-04-06

    ... Animal and Plant Health Inspection Service 7 CFR Part 319 RIN 0579-AD07 Citrus Seed Imports; Citrus... of nursery stock to prohibit the importation of propagative seed of several Rutaceae (citrus family... are also requiring propagative seed of these genera imported from all other countries to...

  15. 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.

  16. Multiple suppressors of RNA silencing encoded by both genomic RNAs of the crinivirus, Tomato chlorosis virus

    OpenAIRE

    Cañizares, Mª Carmen; J. Navas-Castillo; Moriones, E

    2008-01-01

    Viruses express proteins with silencing suppression activity to counteract the RNA silencing-mediated defense response of the host. In the family Closteroviridae, examples of multiple-component RNA silencing suppression systems have been reported

  17. Ultraviolet radiation and sugar-induced chlorosis in detached leaves of Elodea densa

    International Nuclear Information System (INIS)

    When portions of the leaves of Elodea densa were exposed to shortwave ultraviolet (uv) radiation for 20 to 30 s at 2,000 μW/cm2, the chloroplasts of the irradiated tissue did not change in volume and remained green, but chloroplasts of the adjacent nonirradiated tissue decreased in volume, became yellow, and were transformed into yellow-orange chromoplasts during a 5 to 7-day period. Similar changes can be induced in nonirradiated leaves by incubating them in glucose or sucrose solutions. Chloroplasts in uv-exposed leaf tissue, however, remained green and did not decrease in volume even when incubated in glucose or sucrose solutions. Cycloheximide (10 ppM) prevented uv-induced yellowing of adjacent nonirradiated leaf tissue as well as glucose- and sucrose-induced yellowing in nonirradiated leaves. Similarly, cycloheximide prevented sugar-induced anthocyanin synthesis in the light. Cytoplasmic streaming continued in all treatments

  18. The Synechococcus strain PCC 7942 glnN product (glutamine synthetase III) helps recovery from prolonged nitrogen chlorosis.

    Science.gov (United States)

    Sauer, J; Dirmeier, U; Forchhammer, K

    2000-10-01

    We report the cloning and sequencing of the glnN gene encoding a class III glutamine synthetase from the cyanobacterium Synechococcus strain PCC 7942. Mapping of the transcriptional start site revealed a DNA sequence in the promoter region that resembles an imperfect NtcA binding motif. Expression of glnN is impaired in NtcA- and P(II)-deficient mutants. The only parameter which was negatively affected in the glnN mutant compared to the wild type was the recovery rate of prolonged nitrogen-starved cells with low concentrations of combined nitrogen. PMID:10986271

  19. The Synechococcus Strain PCC 7942 glnN Product (Glutamine Synthetase III) Helps Recovery from Prolonged Nitrogen Chlorosis

    OpenAIRE

    Sauer, Jörg; Dirmeier, Ulrike; Forchhammer, Karl

    2000-01-01

    We report the cloning and sequencing of the glnN gene encoding a class III glutamine synthetase from the cyanobacterium Synechococcus strain PCC 7942. Mapping of the transcriptional start site revealed a DNA sequence in the promoter region that resembles an imperfect NtcA binding motif. Expression of glnN is impaired in NtcA- and PII-deficient mutants. The only parameter which was negatively affected in the glnN mutant compared to the wild type was the recovery rate of prolonged nitrogen-star...

  20. Comportamento sazonal da clorose variegada dos citros em três regiões do Estado de São Paulo Seasonal behaviour of citrus variegated chlorosis in three regions of São Paulo State, Brazil

    OpenAIRE

    Francisco F. Laranjeira; Armando Bergamin Filho; Lilian Amorim; João Roberto S. Lopes

    2003-01-01

    Caracterizou-se a evolução de variáveis relacionadas à clorose variegada dos citros em plantas de três regiões do Estado de São Paulo (Noroeste, Centro e Sul), visando determinar diferenças no padrão sazonal do patógeno, dos vetores, do hospedeiro e da doença. Foram avaliadas mensalmente 20 plantas sintomáticas em talhões de laranja (Citrus sinensis) 'Pêra' enxertada em limão (Citrus limonia) 'Cravo', em três regiões do Estado de São Paulo, no período de dezembro de 1998 a dezembro de 2000, u...

  1. 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

    OpenAIRE

    Eduardo Caruso Machado; Ricardo Ferraz de Oliveira; Rafael Vasconcelos Ribeiro; Camilo Lázaro Medina; Eduardo Sanches Stuchi; Fábio Ricardo Marin; José Aliçandro Bezerra da Silva; Simone Rodrigues da Silva

    2006-01-01

    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...

  2. Inactivation of the clpC1 gene encoding a chloroplast Hsp100 molecular chaperone causes growth retardation, leaf chlorosis, lower photosynthetic activity, and a specific reduction in photosystem content.

    Science.gov (United States)

    Sjögren, Lars L E; MacDonald, Tara M; Sutinen, Sirkka; Clarke, Adrian K

    2004-12-01

    ClpC is a molecular chaperone of the Hsp100 family. In higher plants there are two chloroplast-localized paralogs (ClpC1 and ClpC2) that are approximately 93% similar in primary sequence. In this study, we have characterized two independent Arabidopsis (Arabidopsis thaliana) clpC1 T-DNA insertion mutants lacking on average 65% of total ClpC content. Both mutants display a retarded-growth phenotype, leaves with a homogenous chlorotic appearance throughout all developmental stages, and more perpendicular secondary influorescences. Photosynthetic performance was also impaired in both knockout lines, with relatively fewer photosystem I and photosystem II complexes, but no changes in ATPase and Rubisco content. However, despite the specific drop in photosystem I and photosystem II content, no changes in leaf cell anatomy or chloroplast ultrastructure were observed in the mutants compared to the wild type. Previously proposed functions for envelope-associated ClpC in chloroplast protein import and degradation of mistargeted precursors were examined and shown not to be significantly impaired in the clpC1 mutants. In the stroma, where the majority of ClpC protein is localized, marked increases of all ClpP paralogs were observed in the clpC1 mutants but less variation for the ClpR paralogs and a corresponding decrease in the other chloroplast-localized Hsp100 protein, ClpD. Increased amounts of other stromal molecular chaperones (Cpn60, Hsp70, and Hsp90) and several RNA-binding proteins were also observed. Our data suggest that overall ClpC as a stromal molecular chaperone plays a vital role in chloroplast function and leaf development and is likely involved in photosystem biogenesis. PMID:15563614

  3. 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 ...

  4. Influence du type de nutrition azotée sur le déclenchement de la chlorose du sapin de Nordmann (Abies nordmanniana, Spach, 1842)

    OpenAIRE

    Khalil, N.; Leyval, C.; Bonneau, M.; Guillet, B.

    1989-01-01

    Cases of chlorosis have been frequently mentioned in the Nordmann fir (Abies nordmanniana) growing on calcareous soils. Symptoms appear during the early stages of growth and are diagnosed by a needle yellowing. Among the factors implicated in triggering chlorosis, the soil carhonates, bicarbonate-carbonate ionic activity of the soil solution, structure and texture of the soils and the kind of nitrogen nutrition are frequently cited. The characteristics of chlorosis have been studied in ...

  5. Chemical composition on cacao leaves infected by viruses

    International Nuclear Information System (INIS)

    Chemical analysis on cacao leaves that have chlorosis spots caused by cocoa 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. (author tr.)

  6. 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...

  7. 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...

  8. Consequences of iron deficiency on fruit quality in citrus and stawberry

    OpenAIRE

    Pestana, M.; de Varennes, Amarilis; Miguel, Maria Graça; Correia, P. J.

    2010-01-01

    Iron deficiency (iron chlorosis) is an important nutritional disorder in several plants, including fruit trees and strawberry. Iron chlorosis does not result from a small level of iron in soils but rather from impaired acquisition and use of this metal by plants. Calcium carbonate, present in great amounts in calcareous soils, and the resulting large levels of bicarbonate ions, are the main causes of iron deficiency. Countries in southern Europe, such as Portugal, Spain, Italy and...

  9. Adaptation to Fe-deficiency requires remodeling of the photosynthetic apparatus

    OpenAIRE

    Moseley, Jeffrey L.; Allinger, Tanja; Herzog, Sebastian; Hoerth, Patric; Wehinger, Elke; Merchant, Sabeeha; Hippler, Michael

    2002-01-01

    The molecular mechanisms underlying the onset of Fe-deficiency chlorosis and the maintenance of photosynthetic function in chlorotic chloroplasts are relevant to global photosynthetic productivity. We describe a series of graded responses of the photosynthetic apparatus to Fe-deficiency, including a novel response that occurs prior to the onset of chlorosis, namely the disconnection of the LHCI antenna from photosystem I (PSI). We propose that disconnection is mediated by a change in the phys...

  10. Manganese Toxicity in Sugarcane Plantlets Grown on Acidic Soils of Southern China

    Science.gov (United States)

    Huang, Yu Lan; Yang, Shu; Long, Guang Xia; Zhao, Zun Kang; Li, Xiao Feng; Gu, Ming Hua

    2016-01-01

    Ratoon sugarcane plantlets in southern China have suffered a serious chlorosis problem in recent years. To reveal the causes of chlorosis, plant nutrition in chlorotic sugarcane plantlets and the role of manganese (Mn) in this condition were investigated. The study results showed that the pH of soils growing chlorotic plantlets ranged from 3.74 to 4.84. The symptoms of chlorosis were similar to those of iron (Fe) deficiency while the chlorotic and non-chlorotic plantlets contained similar amount of Fe. Chlorotic plantlets had 6.4-times more Mn in their leaf tissues compared to the control plants. There was a significantly positive correlation between Mn concentration in the leaves and the exchangeable Mn concentration in the soils. Moreover, leaf Mn concentration was related to both seasonal changes in leaf chlorophyll concentration and to the occurrence of chlorosis. Basal stalks of mature sugarcanes contained up to 564.36 mg·kg-1 DW Mn. Excess Mn in the parent stalks resulted in a depress of chlorophyll concentration in the leaves of sugarcanes as indicated by lower chlorophyll concentration in the leaves of plantlets emerged from basal stalks. Ratoon sugarcane plantlets were susceptible to chlorosis due to high Mn accumulation in their leaves (456.90–1626.95 mg·kg-1 DW), while in planted canes chlorosis did not occur because of low Mn accumulation (94.64–313.41mg·kg-1 DW). On the other hand, active Fe content in chlorotic plantlets (3.39 mg kg-1 FW) was only equivalent to 28.2% of the concentration found in the control. These results indicate that chlorosis in ratoon sugarcane plantlets results from excessive Mn accumulated in parent stalks of planted cane sugarcanes grown on excessive Mn acidic soils, while active Fe deficiency in plantlets may play a secondary role in the chlorosis. PMID:27023702

  11. 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.

  12. 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...

  13. Evaluation of low-volume sprayers used in asian citrus Psyllid control applications

    Science.gov (United States)

    The Asian citrus psyllid (Diaphorina citri Kumayama, Sternorrhyncha: Psyllidae) is a detrimental pest to citrus crops when it serves as a vector of the pathogen that causes greening (huanglongbing, or HLB). Transmission of this disease causes mottling, chlorosis, dieback and reductions in both frui...

  14. 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 ...

  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. 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...

  17. 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

  18. 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...

  19. THE ROLE OF BRAZIL IN THE WORLD ORANGE JUICE MARKET: A THREAT POSED BY CVC

    OpenAIRE

    Fernandes, Waldir B.; Thomas H. Spreen

    2002-01-01

    The role of the processed citrus industry of Brazil, the largest world orange juice producer, is discussed with reference to CVC (citrus variegated chlorosis), a bacterial disease that affects one-third of the Brazilian tree inventory. Scenarios are analyzed via a spatial equilibrium model on the impact of increased/decreased CVC incidence.

  20. Genetic Differences between Two Strains of Xylella fastidiosa Revealed by Suppression Subtractive Hybridization†

    OpenAIRE

    Harakava, Ricardo; Gabriel, Dean W.

    2003-01-01

    Suppression subtractive hybridization was used to rapidly identify 18 gene differences between a citrus variegated chlorosis (CVC) strain and a Pierce's disease of grape (PD) strain of Xylella fastidiosa. The results were validated as being highly representative of actual differences by comparison of the completely sequenced genome of a CVC strain with that of a PD strain.

  1. Lack of evidence for transmission of Xylella fastidiosa from infected sweet orange seed

    Science.gov (United States)

    Citrus variegated chlorosis is among the principle diseases that affect sweet orange in Brazil and Argentina, and is viewed as an emerging threat by the U.S. sweet orange industry. The disease is caused by the fastidious bacterium Xylella fastidiosa, and can be transmitted by both leafhopper insect...

  2. Two whole genome sequences of Xylella fastidiosa (strains M12 and M23) causing almond leaf scorch disease in California

    Science.gov (United States)

    Xylella fastidiosa is a Gram negative, nutritionally fastidious plant pathogenic bacterium that causes many economically important diseases including almond leaf scorch disease (ALSD) and Pierce’s disease of grape in California, as well as citrus variegated chlorosis in South America. Genome inform...

  3. 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...

  4. 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.

  5. 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...

  6. 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...

  7. [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

  8. [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

  9. CITRUS AND COFFEE STRAINS OF XYLELLA FASTIDIOSA INDUCE PIERCES DISEASE IN GRAPEVINE

    Science.gov (United States)

    Xylella fastidiosa causes citrus variegated chlorosis disease in Brazil and Pierces Disease of grapevines in the United States. Both of these diseases cause significant production problems in the respective industries. The recent establishment of the glassy-winged sharpshooter in California has ra...

  10. CITRUS AND COFFEE STRAINS OF XYELLA FASTIDIOSA INDUCE PIERCE'S DISEASE IN GRAPEVINE

    Science.gov (United States)

    Xyella fastidiosa causes Citrus Varigated Chlorosis (CVC) and Coffee Leaf Scorch (CLS) diseases in Brazil and Pierce's Disease (PD) of grapvine in the United States. All three diseases cause significant production problems in the respective industries. The recent establishment of the glassy-winged...

  11. Using Maize chlorotic dwarf virus to explore future frontiers in plant virology

    Science.gov (United States)

    Maize chlorotic dwarf virus (MCDV) causes a chlorosis and stunting disease of corn throughout the Midwest United States. It is a waikavirus transmitted by the leafhopper Graminella nigrifrons. Although waikaviruses are economically important viruses in corn and rice, little is known about the viru...

  12. 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.

  13. Interactive effects of O3 exposure on California black oak (Quercus kelloggii Newb.) seedlings with and without N amendment

    International Nuclear Information System (INIS)

    We examined the short-term separate and combined effects of simulated nitrogen (N) deposition (fertilization) and ozone (O3) exposure on California black oak seedlings (Quercus kelloggii Newb.), an ecologically important tree of the San Bernardino Mountains downwind of Los Angeles. Realistic concentrations of O3 were found to cause statistically and biologically significant negative effects on plant health, including lowered photosynthetic ability, lowered water use efficiency, and increased leaf chlorosis and necrosis. When subjected to abrupt changes in light levels, O3-exposed plants showed both a slower and smaller response than O3-free plants. Fertilized plants exhibited a significantly greater pre- to post-treatment decline in A at saturated [CO2] and a significantly lower level of post-treatment chlorosis than unfertilized plants. Fertilization tended to reduce plant sensitivity to O3. - Short term O3 exposure reduced carbon acquisition and water use efficiency in Quercus kelloggii seedlings; nitrogen amendment reduced sensitivity to ozone

  14. 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.

  15. Physiolgical and ecological studies of the vegetation on ore deposits, 3; Radioecological symptoms of plants over uranium ore deposits in Koisan, Korea

    International Nuclear Information System (INIS)

    From 1975 to 1981, the survey was carried out to find out radioecological effects of uranium ore deposits on natural vegetation in Koisan, Korea. The symptoms of spotty and mosaic chlorosis, and necrosis were observed in flowering plants in the areas of uranium ore deposits at Deok-Peung-Ri A, B, and C in Koisan. Although 13 species were found to be chlorosis and necrosis, foliages observed are small and very rare. The features of these symptoms closely resemble those occured by the effects of heavy metals. The amount of transparent radiation throughout the depth of soils from uranium radiation sources decreases exponentially. The mean contents in leaves of spotty and mosaik chlorotic plants, and soils were 1.36∼1.53 and 5.3∼7.4ppm, respectively

  16. 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...

  17. Effect of Enhanced Zinc Nutrition on Mitigation of Huanglongbing (HLB)-affected Citrus

    OpenAIRE

    Li, S L; Li, Z. G.; He, Z. L.

    2014-01-01

    The growth decline of huanglongbing (HLB)-affected citrus trees is considered to be associated with nutritional disorder, as typical symptoms of HLB such as stunted tree growth, chlorosis or blotchy mottle of leaves, resembles zinc (Zn), iron (Fe) and manganese (Mn) deficiencies, while lower Zn concentration has been consistently reported in the HLB affected compared to healthy plants. Hydroponic culture studies were conducted to evaluate the effects of enhanced Zn nutrition on the mitigation...

  18. Molecular and morphological identification of mealybug species (Hemiptera: Pseudococcidae) in brazilian vineyards

    OpenAIRE

    Pacheco da Silva, Vitor Cezar; Bertin, Aline; Blin, Aurélie; Germain, Jean-Francois; Bernardi, Daniel; Rignol, Guylène; Botton, Marcos

    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 Braz...

  19. 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...

  20. 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...

  1. 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.

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

    OpenAIRE

    Vladimir Vukadinović; Vesna Vukadinović; Irena Jug; Željko Kraljičak; Boris Đurđević

    2008-01-01

    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...

  3. Genetic linkage maps of 'Pêra' sweet orange and 'Cravo' mandarin with RAPD markers Mapas genéticos de ligação de laranja 'Pêra' e tangerina 'Cravo' utilizando marcadores RAPD

    OpenAIRE

    Roberto Pedroso de Oliveira; Mariângela Cristofani; Marcos Antônio Machado

    2004-01-01

    The objective of this work was to construct linkage maps of 'Pêra' sweet orange [Citrus sinensis (L.) Osbeck] and 'Cravo' mandarin (Citrus reticulata Blanco) using RAPD markers and the pseudo-testcross strategy. The parents were chosen according to the resistance/susceptibility to citrus variegate chlorosis (CVC). The segregation of 176 markers was analyzed in 94 progeny of F1 hybrids, which were obtained from controlled crossings. The linkage map of 'Pêra' sweet orange had 117 markers define...

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

    OpenAIRE

    Abolghassem Emamverdian; Yulong Ding; Farzad Mokhberdoran; Yinfeng Xie

    2015-01-01

    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 ...

  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. 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...

  8. 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...

  9. Callus Induction and Adventitious Shoot Regeneration from Different Explants of Rootstocks GF-677 (Prunus amygdalus x P. persica)

    OpenAIRE

    ELEKTRA SPAHIU; PETRIT RAMA; BARI HODAJ

    2015-01-01

    GF-677 is one of the most suitable rootstocks for almond and peach used in calcareous soils to overcome lime induced chlorosis. The objective of this study is the in vitro cultivation of the peach rootstock GF-677, in determining the protocol for inoculation and for micropropagation in the medium, influencing the development and the outgrowth of the rootstock. The present study focused on the effect of different explants of this rootstock on regenerative potential tissue culture techniques. T...

  10. Micropropagation of phytoplasma-affected Limonium sinuatum Mill. plants

    OpenAIRE

    Eleonora Gabryszewska; Maria Kamińska; Małgorzata Korbin; Anna Rudzińska-Langwald

    2014-01-01

    Healthy and AY-affected plants of L.sinuatum have been propagated in vitro for 12 months on the media with and without cytokinins. In the contrary to the healthy plants the phytoplasma affected statice showed abnormal proliferation of the axillary shoots, shortening of the internodes, smaller leaves and severe chlorosis. On the medium without cytokinins, diseased plants proliferated and formed 7.0 axillary shoots per explant but the healthy ones only formed 2.3 shoots; however, the fresh weig...

  11. 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

    OpenAIRE

    Amin Imran; Patil Basavaprabhu L; Briddon Rob W; Mansoor Shahid; Fauquet Claude M

    2011-01-01

    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 describe...

  12. Nitrogen Starvation Acclimation in Synechococcus elongatus: Redox-Control and the Role of Nitrate Reduction as an Electron Sink

    Directory of Open Access Journals (Sweden)

    Alexander Klotz

    2015-03-01

    Full Text Available Nitrogen starvation acclimation in non-diazotrophic cyanobacteria is characterized by a process termed chlorosis, where the light harvesting pigments are degraded and the cells gradually tune down photosynthetic and metabolic activities. The chlorosis response is governed by a complex and poorly understood regulatory network, which converges at the expression of the nblA gene, the triggering factor for phycobiliprotein degradation. This study established a method that allows uncoupling metabolic and redox-signals involved in nitrogen-starvation acclimation. Inhibition of glutamine synthetase (GS by a precise dosage of l-methionine-sulfoximine (MSX mimics the metabolic situation of nitrogen starvation. Addition of nitrate to such MSX-inhibited cells eliminates the associated redox-stress by enabling electron flow towards nitrate/nitrite reduction and thereby, prevents the induction of nblA expression and the associated chlorosis response. This study demonstrates that nitrogen starvation is perceived not only through metabolic signals, but requires a redox signal indicating over-reduction of PSI-reduced electron acceptors. It further establishes a cryptic role of nitrate/nitrite reductases as electron sinks to balance conditions of over-reduction.

  13. Nitrogen Starvation Acclimation in Synechococcus elongatus: Redox-Control and the Role of Nitrate Reduction as an Electron Sink.

    Science.gov (United States)

    Klotz, Alexander; Reinhold, Edgar; Doello, Sofía; Forchhammer, Karl

    2015-01-01

    Nitrogen starvation acclimation in non-diazotrophic cyanobacteria is characterized by a process termed chlorosis, where the light harvesting pigments are degraded and the cells gradually tune down photosynthetic and metabolic activities. The chlorosis response is governed by a complex and poorly understood regulatory network, which converges at the expression of the nblA gene, the triggering factor for phycobiliprotein degradation. This study established a method that allows uncoupling metabolic and redox-signals involved in nitrogen-starvation acclimation. Inhibition of glutamine synthetase (GS) by a precise dosage of l-methionine-sulfoximine (MSX) mimics the metabolic situation of nitrogen starvation. Addition of nitrate to such MSX-inhibited cells eliminates the associated redox-stress by enabling electron flow towards nitrate/nitrite reduction and thereby, prevents the induction of nblA expression and the associated chlorosis response. This study demonstrates that nitrogen starvation is perceived not only through metabolic signals, but requires a redox signal indicating over-reduction of PSI-reduced electron acceptors. It further establishes a cryptic role of nitrate/nitrite reductases as electron sinks to balance conditions of over-reduction. PMID:25780959

  14. 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)

  15. 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.

  16. 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...

  17. 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...

  18. 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:...

  19. Molecular characterisation of phytoplasmas infecting roses in Poland

    OpenAIRE

    Hanna Śliwa; Tadeusz Malinowski; Maria Kamińska

    2013-01-01

    Symptoms of shoot dieback and leaf yellowing followed by leaf chlorosis were observed in naturally infected roses 'Frisco' and 'Suela', cultivated in a commercial greenhouse in Poland. The presence of phytoplasma was demonstrated in affected plants by nested polymerase chain reaction (PCR) with R16Fl/RO and Pl/P7 primer pairs in the first round followed by a second one with R16F2n/R2, fA/rA, Pc399/P1694, R16(I)Fl/Rl and Pl/fArev primer pairs. Restriction fragment length polymorphism (RFL...

  20. Nucleotide sequence of a chickpea chlorotic stunt virus relative that infects pea and faba bean in China.

    Science.gov (United States)

    Zhou, Cui-Ji; Xiang, Hai-Ying; Zhuo, Tao; Li, Da-Wei; Yu, Jia-Lin; Han, Cheng-Gui

    2012-07-01

    We determined the genome sequence of a new polerovirus that infects field pea and faba bean in China. Its entire nucleotide sequence (6021 nt) was most closely related (83.3% identity) to that of an Ethiopian isolate of chickpea chlorotic stunt virus (CpCSV-Eth). With the exception of the coat protein (encoded by ORF3), amino acid sequence identities of all gene products of this virus to those of CpCSV-Eth and other poleroviruses were pea mild chlorosis virus is proposed. PMID:22476900

  1. The Role of Molybdenum in Biological Nitrogen Fixation

    Directory of Open Access Journals (Sweden)

    Armiadi

    2009-09-01

    Full Text Available The availability of soil Molybdenum (Mo especially for acid soil is scarcely found, while their existency determines the process of Nitrogen fixation. Mo is the component of meta-protein nitrogenase which helps the process of biological nitrogen fixation and acts as essential component which needed for N bacteria metabolism. The nitrogenase enzyme needs Mo element in the process of its metabolism, which acts as electron carrier between oxidized and reduction stages. The deficiency of Mo has been reported in several crops, with various appearance, such as chlorosis or yellowish leaves. The paper describes the role of Mo in biological nitrogen fixation.

  2. 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...

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

    OpenAIRE

    Ngouajio, M.; Hagood, ES.

    1991-01-01

    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 ...

  4. The absorption and transportation of ferric-salt in apple trees

    International Nuclear Information System (INIS)

    59Fe tracer technique was used to study the ferric-salt absorption, utilization and transportation in apple trees. The results indicated that absorption and utilization rate of ferric salt was 0.056%∼0.110% for roots and 30% for leaves, and that Fe is not easily to be transferred from one part to another. Fulvic acid iron had a better effect than ferrous sulfate. Ferric-salt absorption, utilization and transference were different among the cultivars. Intensive injections of ferrous salt into the apple trunks seemed to be more effective for correcting of chlorosis

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

    OpenAIRE

    Emanoela Nardes; Maurício Garcia de Camargo; Paulo Cunha Lana

    2013-01-01

    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 a...

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

    Science.gov (United States)

    Cary; R. Bruce; Stubben, Christopher J.

    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.

  7. 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

  8. 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...

  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. 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.

  11. Air pollution effects on the structure of Citrus aurantium leaves

    Energy Technology Data Exchange (ETDEWEB)

    Psaras, G.K.; Christodoulakis, N.S.

    1987-09-01

    Individual air pollutants cause acute and chronic plant injury, act on stomata and affect carbon dioxide exchange as well as plant growth and development. Inhibition of photosynthesis by several air pollutants has been reported repeatedly. Besides, structural modifications of cell organelles have been reported after fumigation by SO/sub 2/. Although chlorosis and subsequent necrosis are common phenomena caused by artificial treatment with pollutants, fine structural leaf characteristics of plants exposed to long-term air pollution in natural conditions are little explored. Light microscope examination of air pollution affected leaves of plants common in natural ecosystems of Athens' metropolitan area revealed chlorosis phenomena. Electron microscope examination of the leaves of a common subshrub of greek phryganic formations grown in a heavily air polluted natural ecosystem of Athens metropolitan area revealed pronounced ultrastructural anomalies of chloroplasts, mitochondria and microbodies of the mesophyll cells. This organelle destruction of the photosynthesizing tissue as well as the minimization of the ecosystem primary productivity are attributed to the compound action of several toxic air pollutants of the photochemical smog of Athens. This work describes the long-term air pollution effects on the structural features of the leaves of Citrus aurantium, a decorative species planted throughout the heavily air polluted city of Athens.

  12. 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.

  13. Amiprophosmethyl-induced efficient in vitro production of polyploids in raphanobrassica with the aid of aminoethoxyvinylglycine (AVG) in the culture medium.

    Science.gov (United States)

    Niimi, Hiroyuki; Watanabe, Masami; Serizawa, Hiroaki; Koba, Takato; Nakamura, Ikuo; Mii, Masahiro

    2015-12-01

    Optimum conditions for obtaining tetraploid were investigated in raphanobrassica, the intergeneric hybrid between radish (Raphanus sativus) and kale (Brassica oleracea var. acephala) by treating in vitro plants with an anti-mitotic agent, amiprophosmethyl (APM). Initially, no tetraploids but hexaploids and octaploids were induced by the treatments. Although the leaves of these polyploids of raphanobrassica showed chlorosis during subcultures in in vitro conditions, the chlorosis could be successfully prevented by the ethylene inhibitors, both AVG and AgNO3. Based on this result, AVG was added into medium used for the culture after the chromosome doubling treatment, which subsequently resulted in increased survival rates of the treated plant materials as well as increased production rates of polyploids including tetraploid. These polyploid plants showed obviously different characters from the original diploid plant. The tetraploid plant had bigger sizes in shoot, flower and leaf, and more number of leaves than the diploid. On the other hand, the hexaploid and octaploid plants had smaller sizes in shoots and leaves, and less number of leaves than the diploid. Concentration of glucosinolates, functional substances of Brassicaceae crops, did not significantly differ between diploid and tetraploid of raphanobrassica, but reduced in hexaploid and octaploid. PMID:26719742

  14. Adaptation to Fe-deficiency requires remodeling of the photosynthetic apparatus.

    Science.gov (United States)

    Moseley, Jeffrey L; Allinger, Tanja; Herzog, Sebastian; Hoerth, Patric; Wehinger, Elke; Merchant, Sabeeha; Hippler, Michael

    2002-12-16

    The molecular mechanisms underlying the onset of Fe-deficiency chlorosis and the maintenance of photosynthetic function in chlorotic chloroplasts are relevant to global photosynthetic productivity. We describe a series of graded responses of the photosynthetic apparatus to Fe-deficiency, including a novel response that occurs prior to the onset of chlorosis, namely the disconnection of the LHCI antenna from photosystem I (PSI). We propose that disconnection is mediated by a change in the physical properties of PSI-K in PSI in response to a change in plastid Fe content, which is sensed through the occupancy, and hence activity, of the Fe-containing active site in Crd1. We show further that progression of the response involves remodeling of the antenna complexes-specific degradation of existing proteins coupled to the synthesis of new ones, and establishment of a new steady state with decreased stoichiometry of electron transfer complexes. We suggest that these responses are typical of a dynamic photosynthetic apparatus where photosynthetic function is optimized and photooxidative damage is minimized in graduated responses to a combination of nutrients, light quantity and quality. PMID:12485992

  15. 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

  16. 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.

  17. 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

  18. Molecular and biological characterization of corchorus mottle virus, a new begomovirus from Brazil.

    Science.gov (United States)

    Blawid, Rosana; Fontenele, Rafaela S; Lacorte, Cristiano; Ribeiro, Simone G

    2013-12-01

    A begomovirus infecting Orinoco jute (Corchorus hirtus) from Brazil was characterized. Molecular analysis revealed a bipartite genomic organization, which is typical of the New World begomoviruses. Sequence analysis and phylogenetic data showed that both genomic components have the closest relationship with abutilon mosaic Brazil virus, with an identity of 87.3 % for DNA-A, indicating that this virus is a member of a new begomovirus species for which the name "Corchorus mottle virus" (CoMoV) is proposed. Sida rhombifolia plants inoculated by biolistics with an infectious clone of CoMoV showed systemic vein chlorosis, mottling and leaf deformation symptoms, while Nicotiana benthamiana and tomato plants had symptomless infection. CoMoV is the first corchorus-infecting begomovirus reported in Brazil. PMID:23812656

  19. 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.

  20. Effect of cadmium on growth, protein content and peroxidase activity in pea plants

    International Nuclear Information System (INIS)

    n this study the effects of different cadmium chloride concentrations (5, 10, 20, 50, and 100 mu M) on some physiological and biochemical processes including seed germination, root and shoot fresh and dry weight, protein content and peroxidase activity in peas (Cicer arietinum cv. pars) were investigated. Cadmium did not have any significant effect on the rate of pea seed germination. However, it affected the subsequent growth rate in these plants. Higher cadmium concentrations specially at 50 and 100 mu M reduced plant growth significantly. Leaf chlorosis, wilting and leaf abscission were observed in plants treated with cadmium. Protein content in pea roots reduced significantly in the presence of high cadmium concentrations. Low concentrations of CdCl/sub 2/ resulted in higher peroxidase activity both in roots and shoots of pea plants. (author)

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Domino effect of pollution from sour gas fields : failing legume nodulation and the honey industry

    International Nuclear Information System (INIS)

    The sustainability of the honey industry in Alberta's Peace Country has been threatened by pollution from sour gas fields. The region has suffered crop reductions and chlorosis in grains, grasses, and legumes. Severe die-back and die-off of aspens and poplars has also been observed. Crops per colony were reduced by as much as 75 per cent, and winter losses more than tripled. Nectar flow patterns shifted from main flow in early summer to late flows in August or September from second growth alfalfa. A sampling of 27 fields found nitrogen fixation in alfalfa and red clovers lacking in areas downwind from major oil and sour gas flaring facilities. The reduction of the early season nectar flow appears to be caused by the synergistic interaction of ozone and sulphur compounds when ozone levels are at their highest. Reduced ozone levels in the fall permit a late, but uncertain flow from alfalfa plants

  7. Experiences with the use of remote-sensing data with regard to pine trees. Erfahrungen beim Einsatz von Fernerkundungsdaten an der Baumart Kiefer

    Energy Technology Data Exchange (ETDEWEB)

    Kuebler, K.; Ammer, U.; Franken, W. (Muenchen Univ. (Germany, F.R.). Lehrstuhl fuer Landschaftstechnik); Reinhartz, P. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany, F.R.). Inst. fuer Optoelektronik)

    1990-11-01

    At the test site 'Haunstetter Wald' near the city of Augsburg investigations with remotely sensed pine stands (Pinus sylvestris L.) were carried out. The first point in the study dealt with the question of true interpretation of vitality, especially when comparing features on the ground and from the air. We found evident differences between the two interpretation methods. In a further step scanner data collected during low-level flights were analyzed to look for spectral reflection differences between pine and other tree species. Actually there were differences between various species and between damage classes like needle loss and chlorosis. Finally, a pine stand slightly differing from its environment could automatically be classified using a data set from 1000 m flight altitude. The results corresponded satisfactorily with those obtained from true color and CIR-images. (orig.).

  8. 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.

  9. Crystallization and preliminary X-ray analysis of stationary phase survival protein E (SurE) from Xylella fastidiosa in two crystal forms

    International Nuclear Information System (INIS)

    The crystallization and preliminary analysis of two crystal forms of survival protein E from X. fastidiosa are reported. The bacterium Xylella fastidiosa is a phytopathogenic organism that causes citrus variegated chlorosis, a disease which attacks economically important crops, mainly oranges. In this communication, the crystallization and preliminary X-ray crystallographic analysis of XfSurE, a survival protein E from X. fastidiosa, are reported. Data were collected for two crystal forms, I and II, to 1.93 and 2.9 Å resolution, respectively. Crystal form I belonged to space group C2, with unit-cell parameters a = 172.36, b = 84.18, c = 87.24 Å, α = γ = 90, β = 96.59°, whereas crystal form II belonged to space group C2, with unit-cell parameters a = 88.05, b = 81.26, c = 72.84 Å, α = γ = 90, β = 94.76°

  10. [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

  11. Evaluation of the potential of Pistia stratiotes L. (water lettuce) for bioindication and phytoremediation of aquatic environments contaminated with arsenic.

    Science.gov (United States)

    Farnese, F S; Oliveira, J A; Lima, F S; Leão, G A; Gusman, G S; Silva, L C

    2014-08-01

    Specimens of Pistia stratiotes were subjected to five concentrations of arsenic (As) for seven days. Growth, As absorption, malondialdehyde (MDA) content, photosynthetic pigments, enzymatic activities, amino acids content and anatomical changes were assessed. Plant arsenic accumulation increased with increasing metalloid in the solution, while growth rate and photosynthetic pigment content decreased. The MDA content increased, indicating oxidative stress. Enzymatic activity and amino acids content increased at the lower doses of As, subsequently declining in the higher concentrations. Chlorosis and necrosis were observed in the leaves. Leaves showed starch accumulation and increased thickness of the mesophyll. In the root system, there was a loss and darkening of roots. Cell layers formed at the insertion points on the root stems may have been responsible for the loss of roots. These results indicate that water lettuce shows potential for bioindication and phytoremediation of As-contaminated aquatic environments. PMID:25627371

  12. [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

  13. 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

  14. Kinetics of Fe+2 uptake from different iron sources by low-chill peach leaf discs using 59Fe as radiotracer

    International Nuclear Information System (INIS)

    Iron chlorosis is a universal problem of peach cultivation in alkaline and calcareous soils. The foliar fertilization method of iron application is one of the best solutions to this problem. The aim of this study was to examine the kinetics of 59Fe up take through different iron sources by low-chill peach leaf discs. Three different iron sources viz. ferrous sulphate, ferric citrate and FeEDTA were used in this study. Dual pattern of iron up take was obtained when 0.5 per cent ferrous sulphate was used. The uptake of ferrous sulphate was found to be the maximum at 40 min. Both ferric citrate (0.5 per cent) and FeEDTA (0.1 per cent) showed an exponentially increased uptake up to 10 min. (author)

  15. Influence of nitrogen and Bradyrhizobium japonicum on the growth of late maturing soybean by using 15N method

    International Nuclear Information System (INIS)

    The successful of symbiosis between soybean and rhizobia is only possible under favorable soil condition. Only then biological N2 fixation may occur. The objective of this study was to determine the effect of N-fertilizer and Bradyrhizobium japonicum on the growth and yield of late maturing soybean by using 15N. The experiment was conducted at the Department of Agronomy at Bogor in an Inceptisol from Darmaga. Due to high level of Mn-exchangeable resulted from gamma radiation to sterilize the soil, nodulation failed totality. Soybean plant showed chlorosis and Mn toxicity symptoms. Soybean were only affected by N-fertilizer levels. 90 kg ha-1, which at this rate gave the highest shoot and root weights, but tended to lower in total N of plant than 0,45 kg and 135 kg N/ha, respectively. The higher nitrogen fertilizer dose , the higher uptake nitrogen derived from fertilizer. Seed were not formed. (author)

  16. 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

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

    Science.gov (United States)

    Janos, David P; Scott, John; Aristizábal, Catalina; Bowman, David M J S

    2013-01-01

    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. PMID:23460899

  18. 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

  19. Evaluation sous serre de la tolérance à la salinité de quelques porte-greffes d'agrumes : Citrus aurantium et deux hybrides de Poncirus trifoliata (Poncirus x Citrus sinensis et Poncirus x Mandarinier sunki

    Directory of Open Access Journals (Sweden)

    Abdellatif R.

    2005-01-01

    Full Text Available Citrus rootstocks response to salinity. To determine the effects of salinity on the intensity of chlorosis, growth and uptake of Na+ and Cl-, we grew three Citrus rootstocks (sour orange Citrus aurantium (C.a and two new hybrids of Poncirus trifoliata [P.t. x Citrus sinensis (PXC and P.t. x Mandarinier sunki (PXM] in nutrient solutions containing 0, 35 or 70 mM NaCl during 30 or 60 days. Foliar damages increase with time for all treatments and rootstocks. The intensity and the frequency of the chlorosis caused after 30 days of saline stress reveal the sensitivity of PXC and the tolerance of PXM. Moreover, if apical growth of the C.a is not affected by 35 mM NaCl, it is stimulated on the other hand for PXM and is inhibited for PXC. The concentration 70 mM NaCl affects the vigour of rootstocks more severely and shows the tolerance of PXM and the sensitivity of PXC. The biomass decreases with time for all treatments and rootstocks. However, it appears that the concentration 35 mM NaCl is insufficient for the discrimination between rootstocks against salt stress. But, at 70 mM NaCl, the reduction of the biomass confirms the sensitivity of PXC and proves the tolerance of PXM. Furthermore, the content of leaves in Cl- and Na+ is affected meaningfully by salinity, time of stress and rootstocks (PXM appears to be efficient excluding of Cl-. Contents in Na+ and Cl- are correlated with foliar toxicity symptoms. This content is also correlated with biomass reduction of PXC. Therefore, in addition to inhibitory effects of high concentrations of Cl- and Na+, an imbalance of essential nutrients may also contribute to the reduction in growth of this rootstocks under saline conditions.

  20. 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.

  1. 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.

  2. Defence reactions in the apoplastic proteome of oilseed rape (Brassica napus var. napus attenuate Verticillium longisporum growth but not disease symptoms

    Directory of Open Access Journals (Sweden)

    Kües Ursula

    2008-12-01

    Full Text Available Abstract Background Verticillium longisporum is one of the most important pathogens of Brassicaceae that remains strictly in the xylem during most stages of its development. It has been suggested that disease symptoms are associated with clogging of xylem vessels. The aim of our study was to investigate extracellular defence reactions induced by V. longisporum in the xylem sap and leaf apoplast of Brassica napus var. napus in relation to the development of disease symptoms, photosynthesis and nutrient status. Results V. longisporum (strain VL43 did not overcome the hypocotyl barrier until 3 weeks after infection although the plants showed massive stunting of the stem and mild leaf chlorosis. During this initial infection phase photosynthetic carbon assimilation, transpiration rate and nutrient elements in leaves were not affected in VL43-infected compared to non-infected plants. Proteome analysis of the leaf apoplast revealed 170 spots after 2-D-protein separation, of which 12 were significantly enhanced in response to VL43-infection. LS-MS/MS analysis and data base searches revealed matches of VL43-responsive proteins to an endochitinase, a peroxidase, a PR-4 protein and a β-1,3-glucanase. In xylem sap three up-regulated proteins were found of which two were identified as PR-4 and β-1,3-glucanase. Xylem sap of infected plants inhibited the growth of V. longisporum. Conclusion V. longisporum infection did not result in drought stress or nutrient limitations. Stunting and mild chlorosis were, therefore, not consequences of insufficient water and nutrient supply due to VL43-caused xylem obstruction. A distinct array of extracellular PR-proteins was activated that might have limited Verticillium spreading above the hypocotyl. In silico analysis suggested that ethylene was involved in up-regulating VL43-responsive proteins.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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)

  11. Heavy metal toxicities in vegetable crops. I. Effect of zinc concentration in nutrient solution on growth of vegetable crops

    Energy Technology Data Exchange (ETDEWEB)

    Osawa, T.

    1971-01-01

    Fourteen species of vegetable crops were grown in solution culture with addition of zinc, in order to investigate the symptom of zinc toxicity and relative tolerance of vegetable species to zinc. With the increasing concentration of zinc in the nutrient solution, the plant growth was generally inhibited. In the 30 ppm zinc treatment, most vegetable crops showed especially poor growth accompanied with chlorosis. The relative tolerance of vegetable crops to zinc was evaluated according to the concentration of zinc in the nutrient solution corresponding to a 50 per cent reduction in dry weight of tops. Welsh onion did not show the 50 per cent yield reduction even in the highest zinc treatment. In Japanese hornwort, carrot, and celery the 50 per cent yield reduction was observed between the 10 and 30 ppm zinc treatments, and in several crops including fruit vegetables, Cruciferous vegetables, and lettuce between the 3 and 10 ppm zinc treatments. Spinach was estimated to be most susceptible, which showed the 50 per cent yield reduction between the 1 and 3 ppm zinc treatments. In most crops, the concentration of zinc in leaves of control plants was less than 100 ppm in dry matter and increased with the increasing supply of zinc in the nutrient solution. There was no evident relation between the zinc accumulating capacity in leaves and the relative tolerance of vegetable crops to zinc. The accumulation of zinc in roots was generally higher than that in leaves.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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. PMID:25062012

  14. Differential expression of the lethal gene Luteus-Pa in cacao of the Parinari series.

    Science.gov (United States)

    Rehem, B C; Almeida, A-A F; Figueiredo, G S F; Gesteira, A S; Santos, S C; Corrêa, R X; Yamada, M M; Valle, R R

    2016-01-01

    The recessive lethal character Luteus-Pa is found in cacao (Theobroma cacao) genotypes of the Parinari series (Pa) and is characterized by expression of leaf chlorosis and seedling death. Several genotypes of the Pa series are bearers of the gene responsible for the expression of the Luteus-Pa character, which can be used as a tool for determining relationships between genotypes of this group. To evaluate this phenomenon, we analyzed the differential expression of genes between mutant seedlings and wild-type hybrid Pa 30 x 169 seedlings, with the aim of elucidating the possible lethal mechanisms of the homozygous recessive character Luteus-Pa. Plant material was harvested from leaves of wild and mutant seedlings at different periods to construct a subtractive library and perform quantitative analysis using real-time PCR. The 649 sequences obtained from the subtractive library had an average length of 500 bp, forming 409 contigs. The probable proteins encoded were grouped into 10 functional categories. Data from ESTs identified genes associated with Rubisco, peroxidases, and other proteins and enzymes related to carbon assimilation, respiration, and photosystem 2. Mutant seedlings were characterized by synthesizing defective PsbO and PsbA proteins, which were overexpressed from 15 to 20 days after seedling emergence. PMID:26910005

  15. Transcriptome analysis of the salivary glands of potato leafhopper, Empoasca fabae.

    Science.gov (United States)

    DeLay, Bridget; Mamidala, Praveen; Wijeratne, Asela; Wijeratne, Saranga; Mittapalli, Omprakash; Wang, Jian; Lamp, William

    2012-12-01

    The potato leafhopper, Empoasca fabae, is a pest of economic crops in the United States and Canada, where it causes damage known as hopperburn. Saliva, along with mechanical injury, leads to decreases in gas exchange rates, stunting and chlorosis. Although E. fabae saliva is known to induce plant responses, little knowledge exists of saliva composition at the molecular level. We subjected the salivary glands of E. fabae to Roche 454-pyrosequencing which resulted significant number (30,893) of expressed sequence tags including 2805 contigs and 28,088 singletons. A high number of sequences (78%) showed similarity to other insect species in GenBank, including Triboliumcastaneum, Drosophilamelanogaster and Acrythosiphonpisum. KEGG analysis predicted the presence of pathways for purine and thiamine metabolic, biosynthesis of secondary metabolites, drug metabolism, and lysine degradation. Pfam analysis showed a high number of cellulase and carboxylesterase protein domains. Expression analysis of candidate genes (alpha amylase, lipase, pectin lyase, etc.) among different tissues revealed tissue-specific expression of digestive enzymes in E. fabae. This is the first study to characterize the sialotranscriptome of E. fabae and the first for any species in the family of Cicadellidae. Due to the status of these insects as economic pests, knowledge of which genes are active in the salivary glands is important for understanding their impact on host plants. PMID:23063500

  16. PATHOGENIC BEHAVIOUR OF ALTERNARIA ALTERNATA AND PHYTOTOXICITY OF ITS CULTURE FILTRATES ON LEPIDIUM SATIVUM: A MEDICINAL HERB OF IMMENSE PHARMACOLOGICAL POTENTIAL

    Directory of Open Access Journals (Sweden)

    U. K. KHARE

    2013-01-01

    Full Text Available Alternaria alternata causing leaf spot in Lepidium sativum was isolated and purified from diseased leaf tissuescollected from collected from the Medicinal and Aromatic plant garden, Department of Crop and HerbalPhysiology, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (M.P.; isolated and purified on Potato DextroseAgar media. Microscopic examination of a seven days old culture revealed hyaline, septate and branched mycelia,conidiophores with 30.0-80.2 µ length and 3-6 µ width and obclavate to obpyriform conidia (23-30 x 9.2-12.7µ with short conical beak arranged in acropetal fashion. The isolated culture and its culture filtrates wereinoculated to germinated seedlings of chandrasur and also incubated with healthy leaves in a growth chamber.Typical symptoms of Alternaria leaf spot was observed both in in vivo and in vitro inoculated plantlets anddetached leaves respectively. Chlorosis on the hypocotyls and leaves were observed. A. alternata was consistentlyreisolated from symptomatic leaf tissues on PDA. Thus, an efficient and reliable screening method wherein theeffect of the selection agent (pathogen culture, culture filtrate/phytotoxin was demonstrated providing soundpharmacological rational in terms of micro propagation and development of Alternaria resistant L. sativum, animportant medicinal herb.

  17. 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

  18. 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.

  19. Systems biology and metabolic modelling unveils limitations to polyhydroxybutyrate accumulation in sugarcane leaves; lessons for C4 engineering.

    Science.gov (United States)

    McQualter, Richard B; Bellasio, Chandra; Gebbie, Leigh K; Petrasovits, Lars A; Palfreyman, Robin W; Hodson, Mark P; Plan, Manuel R; Blackman, Deborah M; Brumbley, Stevens M; Nielsen, Lars K

    2016-02-01

    In planta production of the bioplastic polyhydroxybutyrate (PHB) is one important way in which plant biotechnology can address environmental problems and emerging issues related to peak oil. However, high biomass C4 plants such as maize, switch grass and sugarcane develop adverse phenotypes including stunting, chlorosis and reduced biomass as PHB levels in leaves increase. In this study, we explore limitations to PHB accumulation in sugarcane chloroplasts using a systems biology approach, coupled with a metabolic model of C4 photosynthesis. Decreased assimilation was evident in high PHB-producing sugarcane plants, which also showed a dramatic decrease in sucrose and starch content of leaves. A subtle decrease in the C/N ratio was found which was not associated with a decrease in total protein content. An increase in amino acids used for nitrogen recapture was also observed. Based on the accumulation of substrates of ATP-dependent reactions, we hypothesized ATP starvation in bundle sheath chloroplasts. This was supported by mRNA differential expression patterns. The disruption in ATP supply in bundle sheath cells appears to be linked to the physical presence of the PHB polymer which may disrupt photosynthesis by scattering photosynthetically active radiation and/or physically disrupting thylakoid membranes. PMID:26015295

  20. Rapid, specific and quantitative assays for the detection of the endophytic bacterium Methylobacterium mesophilicum in plants.

    Science.gov (United States)

    Lacava, P T; Li, W B; Araújo, W L; Azevedo, J L; Hartung, J S

    2006-06-01

    Xylella fastidiosa is a xylem-limited bacterium that causes citrus variegated chlorosis disease in sweet orange. There is evidence that X. fastidiosa interacts with endophytic bacteria present in the xylem of sweet orange, and that these interactions, particularly with Methylobacterium mesophilicum, may affect disease progress. However, these interactions cannot be evaluated in detail until efficient methods for detection and enumeration of these bacteria in planta are developed. We have previously developed standard and quantitative PCR-based assays specific for X. fastidiosa using the LightCycler system [Li, W.B., Pria Jr., L.P.M.W.D., X. Qin, and J.S. Hartung, 2003. Presence of Xylella fastidiosa in sweet orange fruit and seeds and its transmission to seedlings. Phytopathology 93:953-958.], and now report the development of both standard and quantitative PCR assays for M. mesophilicum. The assays are specific for M. mesophilicum and do not amplify DNA from other species of Methylobacterium or other bacteria commonly associated with citrus or plant tissue. Other bacteria tested included Curtobacterium flaccumfaciens, Pantoea agglomerans, Enterobacter cloacae, Bacillus sp., X. fastidiosa, Xanthomonas axonopodis pv. citri, and Candidatus Liberibacter asiaticus. We have demonstrated that with these methods we can quantitatively monitor the colonization of xylem by M. mesophilicum during the course of disease development in plants artificially inoculated with both bacteria. PMID:16266765

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  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. 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

  8. A possible scenario for the evolution of Banana streak virus in banana.

    Science.gov (United States)

    Iskra-Caruana, Marie-Line; Chabannes, Matthieu; Duroy, Pierre-Olivier; Muller, Emmanuelle

    2014-06-24

    Outbreaks of Banana streak virus (BSV) have been recorded worldwide where Musa spp. is grown during the last 20 years with no convincing evidence of epidemics. Epidemics were previously reported in Uganda where BSV is currently endemic. BSV is a plant pararetrovirus of the family Caulimoviridae, genus Badnavirus it causes chlorosis leaf streak disease. The information currently available on banana streak disease makes it possible to identify a complex of distinct BSV species each causing the same disease. BSV exists in two states: one as an episomal form, infecting plant cells; the other as viral DNA integrated within the B genome of banana (endogenous BSV-eBSV) forming a viral genome for de novo viral particles. Both forms can be infectious in banana plants. The BSV phylogeny is polyphyletic with BSV distributed in two clades. Clade 1 clusters BSV species that occur worldwide and may have an eBSV counterpart, whereas Clade 3 only comprises BSV species from Uganda. Clearly, two distinct origins explain such BSV diversity. However, the epidemiology/outbreaks of BSV remains unclear and the role of eBSV needs to be clarified. In this review, the biodiversity of BSV is explained and discussed in the light of field and molecular epidemiology data. A scheme is proposed for the co-evolution of BSV and banana based on old or recent infection hypotheses related to African domestication sites and banana dissemination to explain the disease context. PMID:24457073

  9. Studies on nutrient interaction in some soils of egypt using radioactive isotopes

    International Nuclear Information System (INIS)

    With increasing cultivation of improved plant varieties, and the progressive use of high - analysis fertilizers, zinc deficiency in plants is believed to become a common cause for low crop yields, particularly with high application of fertilizer P in many soils of arid and semi - arid regions. Relationships and mechanisms relating phosphorus and zinc are gaining attention and there is still no agreement as to whether the interaction between the two elements is one of antagonizing or augmentation. Some investigators consider the interaction in terms of effect of phosphorus on zinc absorption in roots and / or zinc translocation through the plant. Although fertilizer P may increase plant growth, plants may become deficient in Zn. In such cases, the total uptake of Zn by crop may increases, but its concentration decreases to the deficiency level. lack of Zn in the plant may reduce yield of fruits or grains (Olsen,1972). On the other hand, plants may absorb large amount of Zn rendering its concentration reaching excessive or toxic levels. This would interfere with the normal metabolic function of other nutrients . Excessive uptake of Zn by plants may disturb the metabolic function of Fe, and the plant may suffer from Fe chlorosis even though Fe may be present at normal concentration in plant

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Differential responses in pear and quince genotypes induced by Fe deficiency and bicarbonate.

    Science.gov (United States)

    Donnini, Silvia; Castagna, Antonella; Ranieri, Annamaria; Zocchi, Graziano

    2009-07-15

    Most of the studies carried out on Fe deficiency condition in arboreous plants have been performed, with the exception of those carried out on plants grown in the field, in hydroponic culture utilizing a total iron depletion growth condition. This can cause great stress to plants. By introducing Fe deficiency induced by the presence of bicarbonate, we found significant differences between Pyrus communis L. cv. Conference and Cydonia oblonga Mill. BA29 and MA clones, characterized by different levels of tolerance to chlorosis. Pigment content and the main protein-pigment complexes were investigated by HPLC and protein gel blot analysis, respectively. While similar changes in the structural organization of photosystems (PSs) were observed in both species under Fe deficiency, a different reorganization of the photosynthetic apparatus was found in the presence of bicarbonate between tolerant and susceptible genotypes, in agreement with the photosynthetic electron transport rate measured in isolated thylakoids. In order to characterize the intrinsic factors determining the efficiency of iron uptake in a tolerant genotype, the main mechanisms induced by Fe deficiency in Strategy I species, such as Fe3+-chelate reductase (EC 1.16.1.7) and H+-ATPase (EC 3.6.3.6) activities, were also investigated. We demonstrate that physiological and biochemical root responses in quince and pear are differentially affected by iron starvation and bicarbonate supply, and we show a high correlation between tolerance and Strategy I activation. PMID:19269060

  17. 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.

  18. 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

  19. Assessment of forest damage using Landsat TM, elevation models and digital forest maps

    Energy Technology Data Exchange (ETDEWEB)

    Ekstrand, S.

    1993-09-01

    The main purpose of this study was to examine the capability of Landsat Thematic Mapper to detect damage on Norway spruce in Sweden. The utility of satellite data in forest damage assessments is hampered by spatial variations in stand characteristics such as species composition, age and density. It is also complicated by topographic effects. This thesis describes the response of Landsat TM data to defoliation in Norway spruce, to variations in stand conditions and to topography. In areas with moderate defoliation symptoms but no chlorosis, a damage estimation algorithm based solely on Landsat TM band 4 was more appropriate than earlier proposed ratio algorithms. The usefulness of digitized stand data and digital elevation models for potentially reducing the effects of forest canopy inhomogeneities and terrain variations was investigated. Using a model accounting for these effects, healthy to slightly defoliated spruce forest could be separated from moderately defoliated forest. The method enables an improvement of the earlier documented Landsat TM capability to detect severely damaged forest. 130 refs, 53 figs, 12 tabs Thematic Mapper to detect damage on

  20. 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

  1. 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.

  2. 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.

  3. 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 International Symposium on Soil and Plant Analysis: Soil, Plant and Water Analysis: Quality Analytical Tools for an Era of Ecological Awareness. Soil and Plant Analysis Council, Cancun, Mexico, 36.KCl between 4.5 and 5.5. Except carbocalk, other "slowly-effect" materials can be recommended for liming, especially for vineyards and orchards.

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

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    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.

  5. 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

    2006-01-01

    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.

  6. 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

  7. Zinc and/or cadmium accumulation in Gynura pseudochina (L.) DC. studied in vitro and the effect on crude protein

    Science.gov (United States)

    Panitlertumpai, Natthawoot; Nakbanpote, Woranan; Sangdee, Aphidech; Thumanu, Kanjana; Nakai, Izumi; Hokura, Akiko

    2013-03-01

    Gynura pseudochina (L.) DC. is a zinc (Zn)/cadmium (Cd) hyperaccumulative plant. The aim of this study was to examine the tolerance of G. pseudochina (L.) DC. for Zn and/or Cd accumulation and protein expression. An in vitro tissue culture system was used to control the environment and effects of the microorganisms. Treatments with higher Zn and Cd concentrations increased chlorosis and the accumulation of metals in the root and shoot. Cd treatment at low levels induced the growth of the plant, and the translocation factor was high. A dual treatment with Cd and Zn decreased the metals' toxicity and demonstrated the plant's proclivity to accumulate Cd. The SDS-PAGE and FT-IR analyses showed the effect of the metals' toxicity on protein expression and secondary structure. Moreover, using XAFS techniques, it was demonstrated that treatment with a high Zn concentration (100 mg l-1) resulted in tetrahedral coordination with mixed S/O ligation in the protein extract as compared with Znsbnd O coordination in the protein extract from the control plant cultured in the presence of trace levels of Zn (0.04 mg l-1). This research suggested that G. pseudochina (L.) DC. had properties to tolerate a high Zn and Cd concentration, related to the sulphur proteins.

  8. 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

  9. 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.

  10. A conserved KIN17 curved DNA-binding domain protein assembles with SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 to adapt Arabidopsis growth and development to limiting copper availability.

    Science.gov (United States)

    Garcia-Molina, Antoni; Xing, Shuping; Huijser, Peter

    2014-02-01

    Proper copper (Cu) homeostasis is required by living organisms to maintain essential cellular functions. In the model plant Arabidopsis (Arabidopsis thaliana), the SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 (SPL7) transcription factor participates in reprogramming global gene expression during Cu insufficiency in order to improve the metal uptake and prioritize its distribution to Cu proteins of major importance. As a consequence, spl7 null mutants show morphological and physiological disorders during Cu-limited growth, resulting in lower fresh weight, reduced root elongation, and chlorosis. On the other hand, the Arabidopsis KIN17 homolog belongs to a well-conserved family of essential eukaryotic nuclear proteins known to be stress activated and involved in DNA and possibly RNA metabolism in mammals. In the study presented here, we uncovered that Arabidopsis KIN17 participates in promoting the Cu deficiency response by means of a direct interaction with SPL7. Moreover, the double mutant kin17-1 spl7-2 displays an enhanced Cu-dependent phenotype involving growth arrest, oxidative stress, floral bud abortion, and pollen inviability. Taken together, the data presented here provide evidence for SPL7 and KIN17 protein interaction as a point of convergence in response to both Cu deficiency and oxidative stress. PMID:24335506

  11. 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)

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

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    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.

  13. 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.

  14. 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)

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

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    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. Altered levels of LIL3 isoforms in Arabidopsis lead to disturbed pigment-protein assembly and chlorophyll synthesis, chlorotic phenotype and impaired photosynthetic performance.

    Science.gov (United States)

    Lohscheider, Jens N; Rojas-Stütz, Marc C; Rothbart, Maxi; Andersson, Ulrica; Funck, Dietmar; Mendgen, Kurt; Grimm, Bernhard; Adamska, Iwona

    2015-10-01

    Light-harvesting complex (LHC)-like (LIL) proteins contain two transmembrane helices of which the first bears a chlorophyll (Chl)-binding motif. They are widespread in photosynthetic organisms, but almost nothing is known about their expression and physiological functions. We show that two LIL3 paralogues (LIL3:1 and LIL3:2) in Arabidopsis thaliana are expressed in photosynthetically active tissues and their expression is differentially influenced by light stress. Localization studies demonstrate that both isoforms are associated with subcomplexes of LHC antenna of photosystem II. Transgenic plants with reduced amounts of LIL3:1 exhibited a slightly impaired growth and have reduced Chl and carotenoid contents as compared to wild-type plants. Ectopic overexpression of either paralogue led to a developmentally regulated switch to co-suppression of both LIL3 isoforms, resulting in a circular chlorosis of the leaf rosettes. Chlorotic sectors show severely diminished levels of LIL3 isoforms and other proteins, and thylakoid morphology was changed. Additionally, the levels of enzymes involved in Chl biosynthesis are altered in lil3 mutant plants. Our data support a role of LIL3 paralogues in the regulation of Chl biosynthesis under light stress and under standard growth conditions as well as in a coordinated ligation of newly synthesized and/or rescued Chl molecules to their target apoproteins. PMID:25808681

  17. California black oak response to nitrogen amendment at a high O{sub 3}, nitrogen-saturated site

    Energy Technology Data Exchange (ETDEWEB)

    Grulke, N.E. [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States)]. E-mail: ngrulke@fs.fed.us; Dobrowolski, W. [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Mingus, P. [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Fenn, M.E. [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States)

    2005-10-15

    In a nitrogen (N) saturated forest downwind from Los Angeles, California, the cumulative response to long-term background-N and N-amendment on black oak (Quercus kelloggii) was described in a below-average and average precipitation year. Monthly measurements of leaf and branch growth, gas exchange, and canopy health attributes were conducted. The effects of both pollutant exposure and drought stress were complex due to whole tree and leaf level responses, and shade versus full sun leaf responses. N-amended trees had lower late summer carbon (C) gain and greater foliar chlorosis in the drought year. Leaf water use efficiency was lower in N-amended trees in midsummer of the average precipitation year, and there was evidence of poor stomatal control in full sun. In shade, N-amendment enhanced stomatal control. Small differences in instantaneous C uptake in full sun, lower foliar respiration, and greater C gain in low light contributed to the greater aboveground growth observed. - Despite ecosystem-level N saturation, lower foliar respiration and significant photosynthetic gains under low light conditions resulted in greater wood production in black oak.

  18. California black oak response to nitrogen amendment at a high O3, nitrogen-saturated site

    International Nuclear Information System (INIS)

    In a nitrogen (N) saturated forest downwind from Los Angeles, California, the cumulative response to long-term background-N and N-amendment on black oak (Quercus kelloggii) was described in a below-average and average precipitation year. Monthly measurements of leaf and branch growth, gas exchange, and canopy health attributes were conducted. The effects of both pollutant exposure and drought stress were complex due to whole tree and leaf level responses, and shade versus full sun leaf responses. N-amended trees had lower late summer carbon (C) gain and greater foliar chlorosis in the drought year. Leaf water use efficiency was lower in N-amended trees in midsummer of the average precipitation year, and there was evidence of poor stomatal control in full sun. In shade, N-amendment enhanced stomatal control. Small differences in instantaneous C uptake in full sun, lower foliar respiration, and greater C gain in low light contributed to the greater aboveground growth observed. - Despite ecosystem-level N saturation, lower foliar respiration and significant photosynthetic gains under low light conditions resulted in greater wood production in black oak

  19. 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.

  20. 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.

  1. 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

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

    Directory of Open Access Journals (Sweden)

    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. 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

  4. 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

  5. Cadmium uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Haghiri, F.

    1973-01-01

    Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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

  11. Biomonitoring heavy metal contaminations by moss visible parameters.

    Science.gov (United States)

    Chen, Yang-Er; Cui, Jun-Mei; Yang, Jin-Chuan; Zhang, Zhong-Wei; Yuan, Ming; Song, Chun; Yang, Hui; Liu, Han-Mei; Wang, Chang-Quan; Zhang, Huai-Yu; Zeng, Xian-Yin; Yuan, Shu

    2015-10-15

    Traditional sampling for heavy metal monitoring is a time-consuming and inconvenient method, which also does not indicate contaminants non-invasively and instantaneously. Moss is sensitive to heavy metals and is therefore considered a pollution indicator. However, it is unknown what kind physiological parameters can indicate metal contaminations quickly and non-invasively. Here, we systematically examined the effects of six heavy metals on physiological parameters and photosynthetic activities of two moss species grown in aquatic media or moist soil surface. We suggest that a phenotype with anthocyanin accumulation pattern and chlorosis pattern and two chlorophyll fluorescence parameters with their images can roughly reflect metal species groups, concentrations and differences between the two moss species. In other words, metal contaminations could be roughly estimated visually using the naked eye. Enzymatic and non-enzymatic anti-oxidative abilities and photosynthetic protein contents of Eurhynchium eustegium were higher than those of Taxiphyllum taxirameum, indicating their differential metal tolerance. Neither anti-oxidative abilities nor photosynthetic proteins were found to be ideal indicators. This study provides new ideas to monitor heavy metals rapidly and non-invasively in water or on wetland and moist soil surface. PMID:25919648

  12. 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.

  13. 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.

  14. 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.

  15. 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

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

    Directory of Open Access Journals (Sweden)

    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. 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

  18. A chilling sensitive mutant of Arabidopsis with altered steryl-ester metabolism

    International Nuclear Information System (INIS)

    A chilling-sensitive mutant of Arabidopsis thaliana was isolated and subjected to genetic, physiological, and biochemical analysis. The chilling-sensitive nature of the mutant line is due to a single recessive nuclear mutation at a locus designated chs1. In contrast to wild-type plants, which are not adversely affected by low temperatures, the chs1 mutant is killed by several days of exposure to temperatures below 18 degree C. Following exposure to chilling temperatures, the mutant displays two common symptoms of chilling injury - leaf chlorosis and electrolyte leakage. In these respects, the physiological response of the mutant to low temperatures mimics the response observed in some naturally occurring chilling sensitive species. The biochemical basis of chilling sensitivity was explored by examining the pattern of incorporation of 14CO2 into soluble metabolites and lipids in wild-type and mutant plants. The only difference observed between the mutant and wild type was that following low temperature treatment, the mutant accumulated 10-fold more radioactivity in a specific class of neutral lipids which were identified by a variety of criteria to be steryl-esters. The accumulation of radioactivity in the steryl-ester fraction occurs 24 hours before there is any visible evidence of chilling injury

  19. 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

  20. 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

  1. Effect of nickel-stresses on uptake, pigments and antioxidative responses of water lettuce, Pistia stratiotes L.

    Science.gov (United States)

    Singh, Kavita; Pandey, S N

    2011-05-01

    Water lettuce plants were exposed to various concentrations (0, 0.01,0.1, 1.0 and 10.0 ppm) of nickel as nickel sulphate in nutrient medium. The effect of graded nickel (Ni +2) concentrations on visible symptoms of toxicity, pigments (chlorophyll a, b and total) and antioxidative attributes were evaluated. Plants exposed to high nickel (1.0 and 10.0 ppm) showed visible toxicity symptoms, such as wilting, chlorosis in young leaves, browning of root tips and broken off roots, observed at 6 days after treatment. Nickel was accumulated more in root (863.3 microg g-1 dry weight) than leaves (116.2 microg g-1 dry weight) at 6 days of treatment. Nickel exposure decreased chlorophyll a, b and total chlorophyll contents. Relative water content decreased at high nickel (1.0 and 10.0 ppm).Antioxidants, such as proline content and peroxidase activity increased with increase in nickel concentrations, whereas, other carotenoids and protein contents at 1.0 ppm and activity of catalase at 10 ppm of nickel were decreased. The low level of nickel stimulates photosynthetic pigments and antioxidative attributes. The study may be helpful in phytoremedial strategies and biological indication of nickel toxicity in aquatic plants. PMID:22167955

  2. 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.

  3. 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

  4. 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.

  5. Nitrogen control of chloroplast differentiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1998-05-01

    This project was directed toward understanding at the physiological, biochemical and molecular levels of how photosynthetic organisms adapt to long-term nitrogen-deficiency conditions is quite incomplete even though limitation of this nutrient is the most commonly restricts plant growth and development. For our work on this problem, the unicellular green alga, Chlamydomonas reinhardtii, was grown in continuous cultures in which steady-state levels of nitrogen can be precisely controlled. N-limited cells exhibit the classical symptoms of deficiency of this nutrient, chlorosis and slow growth rates, and respond to nitrogen provision by rapid greening and chloroplast differentiation. We have addressed three aspects of this problem: (1) the regulation of pigment synthesis; (2) control of expression of nuclear genes encoding photosynthetic proteins; (3) changes in metabolic and electron transport pathways that enable sustained CO{sub 2} fixation even though they cannot be readily converted into amino and nucleic acids. For the last, principle components are: (a) enhanced mitochondrial respiratory activity intimately associated with photosynthates, and (b) the occurrence in thylakoids of a supplemental electron transport pathway that facilitates reduction of the plastoquinone pool. Together, these distinguishing features of N-limited cells are likely to enable cell survival, especially under conditions of high irradiance stress.

  6. 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

  7. Leaf domatia mediate mutualism between mites and a tropical tree.

    Science.gov (United States)

    Romero, Gustavo Q; Benson, Woodruff W

    2004-08-01

    Although associations between mites and leaf domatia have been widely reported, their consequences for plants, especially for natural tree populations, particularly in the tropics, are largely unknown. In experiments with paired Cupania vernalis (Sapindaceae) saplings in a semi-deciduous forest in south-east Brazil, we blocked leaf domatia to examine their effect: (1) on mites and other arthropods, and (2) on damage caused by fungi and herbivorous arthropods. In general, plants with resin-blocked domatia had fewer predaceous mites on leaves than control plants with unaltered domatia, but the total abundances of fungivorous and of phytophagous mites remained unchanged. However, phytophagous eriophyid mites, the most numerous inhabitants of domatia, decreased on leaf surfaces with the blocking treatment. In a second experiment, treated plants lacking functional domatia developed significantly greater numbers and areas of chlorosis, apparently due to increased eriophyid attacks, whereas fungal attack, epiphyll abundance and leaf-area loss were unaffected. This seems to be the first experimental study to demonstrate that leaf domatia can benefit plants against herbivory in a natural system. The possible stabilizing effect of leaf domatia on predator-prey interactions is discussed. PMID:15205936

  8. 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.

  9. 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

  10. Relationship Between Mycorrhizal Associations and Tree Phyto-Sanitary Conditions of Urban Woodlands of Bogota D.C., Colombia

    International Nuclear Information System (INIS)

    Spore number and root infection by Arbuscular mycorrhizal fungi were evaluated in Eugenia myrtifolia, Ficus soatensis and Croton bogotensis, in parks and green zones of urban woodlands of Bogota D.C, Colombia. The aim was to investigate relations between mycorrhizal associations and tree phyto-sanitary conditions, and effects of two distinct climatic zones. It was demonstrated that plant species and climate are significant sources of variations in the general mycorrhizal state. Eugenia myrtifolia showed the highest degree of root colonization but the lowest number of spores, while C. 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

  11. 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

  12. 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

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    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. 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. Seedborne fungal contamination: consequences in space-grown wheat

    Science.gov (United States)

    Bishop, D. L.; Levine, H. G.; Kropp, B. R.; Anderson, A. J.; Hood, E. E. (Principal Investigator)

    1997-01-01

    Plants grown in microgravity are subject to many environmental stresses that may promote microbial growth and result in disease symptoms. Wheat (cv. Super Dwarf) recovered from an 8-day mission aboard a NASA (National Aeronautics and Space Administration) space shuttle showed disease symptoms, including girdling of leaf sheaths and chlorosis and necrosis of leaf and root tissues. A Neotyphodium species was isolated from the seed and leaf sheaths of symptomatic wheat used in the spaceflight mission. Certain isozymes of a peroxidase unique to extracts from the microgravity-grown plants were observed in extracts from earth-grown Neotyphodium-infected plants but were not present in noninfected wheat. The endophytic fungus was eliminated from the wheat seed by prolonged heat treatment at 50 degrees C followed by washes with water at 50 degrees C. Plants from wheat seed infected with the Neotyphodium endophyte were symptomless when grown under greenhouse conditions, whereas symptoms appeared after only 4 days of growth in closed containers. Disease spread from an infected plant to noninfected plants in closed containers. Dispersion via spores was found on asymptomatic plants at distances of 7 to 18 cm from infected plants. The size and shape of the conidia, mycelia, and phialide-bearing structures and the ability to grow rapidly on carbohydrates, especially xylose, resembled the characteristics of N. chilense, which is pathogenic on orchard grass, Doctylis glomerati. The Neotyphodium wheat isolate caused disease symptoms on other cereals (wheat cv. Malcolm, orchard grass, barley, and maize) grown in closed containers.

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

    International Nuclear Information System (INIS)

    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 π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we 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 activate 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 (half-lives in hours), 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

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Effects of Reductants on Phytoextraction of Chromium (VI) by Ipomoea aquatica.

    Science.gov (United States)

    Ton, Shan-Shin; Lee, Ming-Wei; Yang, Yin-Hsin; Hoi, Soi-Keong; Cheng, Wen-Che; Wang, Kai-Sung; Chang, Han-Hsin; Chang, Shih-Hsien

    2015-01-01

    Reductants are often used to reduce Cr(VI) in chemical treatments, yet the effects of the reductants on Cr(VI) phytoremediation are not fully understood. This study investigates the effects of different reductants on Cr(VI) phytoremediation by Ipomoea aquatica in simulated solution with 3 mg L(-1) of Cr(VI), pH0 of 6, and an incubation time of 5 days. Results indicate that the applications of S2O3(2-), Fe0, and Fe2+ at low doses notably increased root Cr concentrations, which were obviously higher than that those in the control (Cr6+ alone). However, high reductant concentrations decreased bioaccumulation of Cr in the roots and shoots of the plant. Statistical results indicate that Cr concentrations were significantly and negatively correlated with Fe concentrations in the roots and shoots of the plant (p<0.05). This suggest that Fe accumulation inhibited Cr accumulation in the plant. A Cr(VI) concentration of 3 mg L(-1) caused short, brown lateral roots with tip necrosis, leaf chlorosis, and noticeable shoot wilting. The leaf necrosis and shoot wilting is caused by oxidative damage of lateral roots by Cr(VI) rather than by the reactive oxygen species generated by the oxidative stress. Addition of the reductants effectively reduced these plant injuries. PMID:25495933

  6. 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.

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Leite B.

    2002-01-01

    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.

  12. 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

  13. 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.

  14. 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.

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

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    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.

  16. 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.

  17. Interspecific hybridization among cultivars of hardy Hibiscus species section Muenchhusia.

    Science.gov (United States)

    Kuligowska, Katarzyna; Lütken, Henrik; Christensen, Brian; Müller, Renate

    2016-03-01

    Rose mallows belong to the Muenchhusia section of the Hibiscus genus. They represent a small group of cold tolerant North American plants and are popular ornamentals mainly because of their abundant, large and colorful flowers. Due to their geographical origin they are well suited for garden use in temperate regions worldwide. The aim of the study was to investigate hybridization barriers in crosses among cultivars of Hibiscus species from the Muenchhusia section: H. coccineus, H. laevis and H. moscheutos. Crossing barriers were identified as both pre- and post-zygotic. The analysis of pollen tube growth revealed inhibition of pollen tubes and their abnormal growth. In specific crosses the fertilization success was low. The pre-fertilization barriers did not cause a complete reproductive isolation between the hybridization partners. In relation to post-fertilization barriers, the occurrence of hybrid incompatibilities such as unviability, chlorosis, necrosis, stunted growth and albinism were the main drawback in production of hybrids. The appearance of symptoms of hybrid incompatibilities was dependent upon specific parental plants. The obtained progeny had intermediate leaf morphology and flower morphology compared to parental plants. Hybridity state was verified by morphological analysis and RAPD markers. Based on the overall plant morphology, 472 hybrid progenies were obtained. PMID:27162501

  18. 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

  19. 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

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    Highlights: ► Cd accumulated in stem bottom part exceeded the defined hyperaccumulator threshold. ► No toxic symptoms occurred and TI of all growth parameters ranged between 0.7 and 1. ► The high level of Zn, Mn and Cu may contribute to the absence of chlorosis in stem. ► Cd/Ca synergistic effect observed in the stem may alleviate Cd toxicity. ► 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′ (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.

  3. 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.

  4. 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.

  5. 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.

  6. Artificial recharge of groundwater through sprinkling infiltration: impacts on forest soil and the nutrient status and growth of Scots pine.

    Science.gov (United States)

    Nöjd, Pekka; Lindroos, Antti-Jussi; Smolander, Aino; Derome, John; Lumme, Ilari; Helmisaari, Heljä-Sisko

    2009-05-01

    We studied the chemical changes in forest soil and the effects on Scots pine trees caused by continuous sprinkling infiltration over a period of two years, followed by a recovery period of two years. Infiltration increased the water input onto the forest soil by a factor of approximately 1000. After one year of infiltration, the pH of the organic layer had risen from about 4.0 to 6.7. The NH(4)-N concentration in the organic layer increased, most probably due to the NH(4) ions in the infiltration water, as the net N mineralization rate did not increase. Sprinkling infiltration initiated nitrification in the mineral soil. Macronutrient concentrations generally increased in the organic layer and mineral soil. An exception, however, was the concentration of extractable phosphorus, which decreased strongly during the infiltration period and did not show a recovery within two years. The NO(3)-N and K concentrations had reverted back to their initial level during the two-year recovery period, while the concentrations of Ca, Mg and NH(4)-N were still elevated. Nutrient concentrations in the pine needles increased on the infiltrated plots. However, the needle P concentration increased, despite the decrease in plant-available P in the soil. Despite the increase in the nutrient status, there were some visible signs of chlorosis in the current-year needles after two years of infiltration. The radial growth of the pines more than doubled on the infiltrated plots, which suggests that the very large increase in the water input onto the forest floor had no adverse effect on the functioning of the trees. However, a monitoring period of four years is not sufficient for detecting potential long term detrimental effects on forest trees. PMID:19269680

  7. Fractionated extracts of Russian wheat aphid eliciting defense responses in wheat.

    Science.gov (United States)

    Lapitan, Nora L V; Li, You-Chun; Peng, Junhua; Botha, Anna-Maria

    2007-06-01

    It is hypothesized that the interaction between aphids and plants follows a gene-for-gene model. The recent appearance of several new Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Homoptera: Aphididae), biotypes in the United States and the differential response of wheat, Triticum aestivum L., genotypes containing different resistance genes also suggest a gene-for-gene interaction. However, aphid elicitors remain unknown. This study was conducted to identify fractionated Russian wheat aphid extracts capable of eliciting differential responses between resistant and susceptible wheat genotypes. We extracted whole soluble compounds and separated proteins and metabolites from two Russian wheat aphid biotypes (1 and 2), injected these extracts into seedlings of susceptible wheat Gamtoos (dn7) and resistant 94M370 (Dn7), and determined phenotypic and biochemical plant responses. Injections of whole extract or protein extract from both biotypes induced the typical susceptible symptom, leaf rolling, in the susceptible cultivar, but not in the resistant cultivar. Furthermore, multiple injections with protein extract from biotype 2 induced the development of chlorosis, head trapping, and stunting in susceptible wheat. Injection with metabolite, buffer, or chitin, did not produce any susceptible symptoms in either genotype. The protein extract from the two biotypes also induced significantly higher activities of three defense-response enzymes (catalase, peroxidase, and beta-glucanase) in 94M370 than in Gamtoos. These results indicate that a protein elicitor from the Russian wheat aphid is recognized by a plant receptor, and the recognition is mediated by the Dn7-gene product. The increased activities of defense-response enzymes in resistant plants after injection with the protein fraction suggest that defense response genes are induced after recognition of aphid elicitors by the plant. PMID:17598566

  8. Biochemical and physiological detection of sulfur dioxide injury to pea plants (Pisum sativum)

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, H.J.; Klein, H.

    1977-05-01

    Biochemical and physlological experiments were conducted on pea plants (Pisum sativum) continuously exposed in growth chambers to SO/sub 2/ gas for 18 days. SO/sub 2/ gas concentrations were 0.1, 0.15, and 0.25 ppM. In plants exposed to 0.1 and 0.15 ppM it was clearly demonstrated that there was a greater accumulation of inorganic sulfur, a reduced buffer capacity of the cells relative to H-ions, and a stimulation of glutamate dehydrogenase activity. The only macroscopic symptom seen was slight chlorosis of the older leaves. There was only a slight decrease in fresh and dry weights of these plants compared to the control plants whereas in the group of plants exposed to 0.25 ppM SO/sub 2/ foliage necrosis was considerable. In addition, there was a marked reduction in the fresh and dry weights of the latter plants. However, the relationship among accumulated inorganic sulfur, reduced buffer capacity, and increased glutamate dehydrogenase activity as seen for the lower SO/sub 2/ concentrations was close. Accordingly, it might be possible to use these three parameters to diagnose SO/sub 2/ injury before any significant symptoms appear. In the case of severe SO/sub 2/ injury there was a marked increase in glutamine and ammonia concentrations suggesting that these factors in addition to the above could be used in diagnosing severe SO/sub 2/ injury. There was no significant difference between plants treated with 0.1 or 0.15 ppM SO/sub 2/ and control plants in the contents of K, Ca, P, and N fractions. Therefore, these factors would not be useful in the early detection of SO/sub 2/ injury.

  9. 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

  10. 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. PMID:25900437

  11. 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.

  12. A consortium of rhizobacterial strains and biochemical growth elicitors improve cold and drought stress tolerance in rice (Oryza sativa L.).

    Science.gov (United States)

    Kakar, K U; Ren, X-L; Nawaz, Z; Cui, Z-Q; Li, B; Xie, G-L; Hassan, M A; Ali, E; Sun, G-C

    2016-05-01

    In the present study, a consortium of two rhizobacteria Bacillus amyloliquefaciens Bk7 and Brevibacillus laterosporus B4, termed 'BB', biochemical elicitors salicylic acid and β-aminobutyric acid (SB) and their mixture (BBSB) were investigated for cold and drought stress tolerance in rice plants. After withholding water for 16 days, rice plants treated with BBSB showed 100% survival, improved seedling height (35.4 cm), shoot number (6.12), and showed minimum symptoms of chlorosis (19%), wilting (4%), necrosis (6%) and rolling of leaves. Similarly, BB inoculation enhanced plant growth and reduced overall symptoms in rice seedlings subjected to 0 ± 5 °C for 24 h. Our results imply several mechanisms underlying BB- and BBSB-elicited stress tolerance. In contrast to the control, both treatments significantly decreased leaf monodehydroascorbate (MDA) content and electrolyte leakage, and increased leaf proline and cholorophyll content. Moreover, activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) increased 3.0- and 3.6-fold, respectively. Moreover, expression of OsMYB3R-2, OsDIL, OsDREB1A and OsCDPK13 genes was significantly up-regulated, suggesting that these genes play important roles in abiotic stress tolerance of rice. In addition, bacterial strains Bk7 and B4 were able to produce high amounts of IAA and siderophores, and colonise the plant roots, while only strain Bk7 exhibited the capability to form biofilms and solubilise inorganic phosphate. This study indicates that the BB and BBSB bio-formulations can be used to confer induced systematic tolerance and improve the health of rice plants subject to chilling and drought stress. PMID:26681628

  13. 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.

  14. Variation in susceptibility to Wheat dwarf virus among wild and domesticated wheat.

    Science.gov (United States)

    Nygren, Jim; Shad, Nadeem; Kvarnheden, Anders; Westerbergh, Anna

    2015-01-01

    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 wheat. PMID

  15. 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

  16. 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

  17. Effects of simulated acid rain on germination, seedling growth and oxidative metabolism of recalcitrant-seeded Trichilia dregeana grown in its natural seed bank.

    Science.gov (United States)

    Ramlall, Chandika; Varghese, Boby; Ramdhani, Syd; Pammenter, Norman W; Bhatt, Arvind; Berjak, Patricia; Sershen

    2015-01-01

    Increased air pollution in a number of developing African countries, together with the reports of vegetation damage typically associated with acid precipitation in commercial forests in South Africa, has raised concerns over the potential impacts of acid rain on natural vegetation in these countries. Recalcitrant (i.e. desiccation sensitive) seeds of many indigenous African species, e.g. must germinate shortly after shedding and hence, may not be able to avoid exposure to acid rain in polluted areas. This study investigated the effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2 SO4 :HNO3 ) on germination, seedling growth and oxidative metabolism in a recalcitrant-seeded African tree species Trichilia dregeana Sond., growing in its natural seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, pH 3.0 treated seedlings exhibited signs of stress typically associated with acid rain: leaf tip necrosis, abnormal bilobed leaf tips, leaf necrotic spots and chlorosis, reduced leaf chlorophyll concentration, increased stomatal density and indications of oxidative stress. This may explain why total and root biomass of pH 3.0 treated seedlings were significantly lower than the control. Acid rain also induced changes in the species composition and relative abundance of the different life forms emerging from T. dregeana's natural seed bank and in this way could indirectly impact on T. dregeana seedling establishment success. PMID:24835442

  18. 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

  19. Oxidative stress responses and root lignification induced by Fe deficiency conditions in pear and quince genotypes.

    Science.gov (United States)

    Donnini, Silvia; Dell'Orto, Marta; Zocchi, Graziano

    2011-01-01

    We analysed Pyrus communis cv. Conference and Cydonia oblonga BA29, differently tolerant to lime-induced chlorosis, to identify the key mechanisms involved in their different performance under Fe deficiency induced by the absence of Fe (-Fe) or by the presence of bicarbonate (+FeBic). Under our experimental conditions, a decrease in root elongation was observed in BA29 under bicarbonate supply. Superoxide dismutase (SOD) and peroxidase (POD) activities were analysed and the relative isoforms were detected by native electrophoresis. The data obtained for both genotypes under -Fe and for BA29 +FeBic suggest the occurrence of overproduction of reactive oxygen species (ROS) and, at the same time, of a scarce capacity to detoxify them. The detection of ROS (O(2)(-) and H(2)O(2)) through histochemical localization supports these results and suggests that they could account for the modifications of mechanical properties of the cell wall during stress adaptation. On the other hand, in the cv. Conference +FeBic, an increase in non-specific POD activity was detected, confirming its higher level of protection in particular against H(2)O(2) accumulation. Peroxidases involved in lignification were assayed and histochemical analysis was performed. The results suggest that only in BA29 under bicarbonate supply can the presence of ROS in root apoplast be correlated with lignin deposits in external layers and in endodermis as a consequence of the shift of PODs towards a lignification role. We suggest that in BA29 the decrease in root growth could impair mineral nutrition, generating susceptibility to calcareous soils. In the cv. Conference, the allocation of new biomass to the root system could improve soil exploration and consequently Fe uptake. PMID:21389006

  20. In planta transient expression as a system for genetic and biochemical analyses of chlorophyll biosynthesis

    Directory of Open Access Journals (Sweden)

    Sawers Ruairidh JH

    2006-09-01

    Full Text Available Abstract Background Mg chelatase is a multi-subunit enzyme that catalyses the first committed step of chlorophyll biosynthesis. Studies in higher plants and algae indicate that the Mg chelatase reaction product, Mg-protoporphyrin IX plays an essential role in nuclear-plastid interactions. A number of Mg chelatase mutants have been isolated from higher plants, including semi-dominant alleles of ChlI, the gene encoding the I subunit of the enzyme. To investigate the function of higher plant CHLI, bacterial orthologues have been engineered to carry analogous amino acid substitutions to the higher plant mutations and the phenotypes examined through in vitro characterization of heterologously produced proteins. Here, we demonstrate the utility of a transient expression system in Nicotiana benthamiana for rapidly assaying mutant variants of the maize CHLI protein in vivo. Results Transient expression of mutant maize ChlI alleles in N. benthamiana resulted in the formation of chlorotic lesions within 4 d of inoculation. Immunoblot analyses confirmed the accumulation of maize CHLI protein suggesting that the chlorosis observed resulted from an interaction between maize CHLI and endogenous components of the N. benthamiana chlorophyll biosynthetic pathway. On the basis of this assay, PCR-based cloning techniques were used to rapidly recombine polymorphisms present in the alleles studied allowing confirmation of causative lesions. A PCR-based mutagenesis was conducted and clones assayed by transient expression. A number of novel allelic variants of maize ZmChlI were generated and analyzed using this assay, demonstrating the utility of this technique for fine mapping. Conclusion Transient expression provides a convenient, high-throughput, qualitative assay for functional variation in the CHLI protein. Furthermore, we suggest that the approach used here would be applicable to the analysis of other plastid-localized proteins where gain-of-function mutations

  1. NaCl alleviates Cd toxicity by changing its chemical forms of accumulation in the halophyte Sesuvium portulacastrum.

    Science.gov (United States)

    Wali, Mariem; Fourati, Emna; Hmaeid, Nizar; Ghabriche, Rim; Poschenrieder, Charlotte; Abdelly, Chedly; Ghnaya, Tahar

    2015-07-01

    It has previously been shown that certain halophytes can grow and produce biomass despite of the contamination of their saline biotopes with toxic metals. This suggests that these plants are able to cope with both salinity and heavy metal constraints. NaCl is well tolerated by halophytes and apparently can modulate their responses to Cd. However, the underlying mechanisms remain unclear. This study explores the impact of NaCl on growth, Cd accumulation, and Cd speciation in tissues of the halophyte Sesuvium portulacastrum. Seedlings of S. portulacastrum were exposed during 1 month to 0, 25, and 50 μM Cd combined with low salinity (LS, 0.09 mM NaCl) or high salinity (HS, 200 mM NaCl) levels. Growth parameters and total tissue Cd concentrations were determined, in leaves, stems, and root. Moreover, Cd speciation in these organs was assessed by specific extraction procedures. Results showed that, at LS, Cd induced chlorosis and necrosis and drastically reduced plant growth. However, addition of 200 mM NaCl to Cd containing medium alleviated significantly Cd toxicity symptoms and restored plant growth. NaCl reduced the concentration of Cd in the shoots; nevertheless, due to maintenance of higher biomass under HS, the quantity of accumulated Cd was not modified. NaCl modified the chemical form of Cd in the tissues by increasing the proportion of Cd bound to pectates, proteins, and chloride suggesting that this change in speciation is involved in the positive impact of NaCl on Cd tolerance. We concluded that the tolerance of S. portulacastrum to Cd was enhanced by NaCl. This effect is rather governed by the modification of the speciation of the accumulated Cd than by the reduction of Cd absorption and translocation. PMID:25758421

  2. 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

  3. 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.

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

    International Nuclear Information System (INIS)

    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 CCl4, CHCl3, and Triton X-100, precipitation with PEG-8000 and centrifugation in either Cs2SO4-sucrose cushion gradients or Cs2SO4 equilibrium density gradients. Purified virions formed a single UV-absorbing infectious band with densities of 1.31 and 1.245 g/ml in CsCl2 and Cs2SO4 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 106 under denaturing conditions. Molecular hybridization analysis using 3H-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

  5. 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

  6. 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.

  7. 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.

  8. 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)

  9. [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

  10. 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

  11. Characterization of novel virulent broad-host-range phages of Xylella fastidiosa and Xanthomonas.

    Science.gov (United States)

    Ahern, Stephen J; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry; Gonzalez, Carlos F

    2014-01-01

    The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ~4 × 10(-12) ml cell(-1) min(-1) for X. fastidiosa strain Temecula 1 and ~5 × 10(-10) to 7 × 10(-10) ml cell(-1) min(-1) for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa. PMID:24214944

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. Responses of a triple mutant defective in three iron deficiency-induced Basic Helix-Loop-Helix genes of the subgroup Ib(2) to iron deficiency and salicylic acid.

    Science.gov (United States)

    Maurer, Felix; Naranjo Arcos, Maria Augusta; Bauer, Petra

    2014-01-01

    Plants are sessile organisms that adapt to external stress by inducing molecular and physiological responses that serve to better cope with the adverse growth condition. Upon low supply of the micronutrient iron, plants actively increase the acquisition of soil iron into the root and its mobilization from internal stores. The subgroup Ib(2) BHLH genes function as regulators in this response, however their concrete functions are not fully understood. Here, we analyzed a triple loss of function mutant of BHLH39, BHLH100 and BHLH101 (3xbhlh mutant). We found that this mutant did not have any iron uptake phenotype if iron was provided. However, under iron deficiency the mutant displayed a more severe leaf chlorosis than the wild type. Microarray-based transcriptome analysis revealed that this mutant phenotype resulted in the mis-regulation of 198 genes, out of which only 15% were associated with iron deficiency regulation itself. A detailed analysis revealed potential targets of the bHLH transcription factors as well as genes reflecting an exaggerated iron deficiency response phenotype. Since the BHLH genes of this subgroup have been brought into the context of the plant hormone salicylic acid, we investigated whether the 3xbhlh mutant might have been affected by this plant signaling molecule. Although a very high number of genes responded to SA, also in a differential manner between mutant and wild type, we did not find any indication for an association of the BHLH gene functions in SA responses upon iron deficiency. In summary, our study indicates that the bHLH subgroup Ib(2) transcription factors do not only act in iron acquisition into roots but in other aspects of the adaptation to iron deficiency in roots and leaves. PMID:24919188

  19. Growth analysis of UV-B-irradiated cucumber seedlings as influenced by photosynthetic photon flux source and cultivar

    International Nuclear Information System (INIS)

    A growth analysis was made of ultraviolet-B (UV-B)-sensitive (Poinsett) and insensitive (Ashley) cultivars of Cucuumis satives L. grown in growth chambers at 600 μmol m−2 s−1 of photosynthetic photon flux (PPF) provided by red- and far-red-deficient metal halide (MH) or blue- and UV-A-deficient high pressure sodium/deluxe f HPS/DX) lamps. Plants were irradiated 6 h daily with 0.2 f-UV-B) or 18.2 C+UV-B) kJ m−2 day−1 of biologically effective UV-B for 8 or 15 days from time of seeding. In general, plants given supplemental UV-B for 15 days showed lower leaf area ratio (LARs, and higher specific leaf mass (SLM) mean relative growth rate (MRGR) and net assimilation rate (NAR) than that of control plants, but they showed no difference in leaf mass ratio (LMR), Plants grown under HPS/DX lamps vs MH lamps showed higher SLM and NAR. lower LAR and LMR. hut no difference in MRGR. LMR was the only growth parameter affected by cultivar: at 15 days, it was slightly greater in Poinsett than in Ashley. There were no interactive effects of UV-B. PPF source or cultivar on any of the growth parameters determined, indicating that the choice of either HPS/DX or MH lamps should not affect growth response to UV-B radiation. This was true even though leaves of UV-B-irradiated plants grown under HPS/DX lamps have been shown to have greater chlorosis than those grown under MH lamps. (author)

  20. 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.

  1. 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

  2. NblA, a key protein of phycobilisome degradation, interacts with ClpC, a HSP100 chaperone partner of a cyanobacterial Clp protease.

    Science.gov (United States)

    Karradt, Anne; Sobanski, Johanna; Mattow, Jens; Lockau, Wolfgang; Baier, Kerstin

    2008-11-21

    When cyanobacteria are starved for nitrogen, expression of the NblA protein increases and thereby induces proteolytic degradation of phycobilisomes, light-harvesting complexes of pigmented proteins. Phycobilisome degradation leads to a color change of the cells from blue-green to yellow-green, referred to as bleaching or chlorosis. As reported previously, NblA binds via a conserved region at its C terminus to the alpha-subunits of phycobiliproteins, the main components of phycobilisomes. We demonstrate here that a highly conserved stretch of amino acids in the N-terminal helix of NblA is essential for protein function in vivo. Affinity purification of glutathione S-transferase-tagged NblA, expressed in a Nostoc sp. PCC7120 mutant lacking wild-type NblA, resulted in co-precipitation of ClpC, encoded by open reading frame alr2999 of the Nostoc chromosome. ClpC is a HSP100 chaperone partner of the Clp protease. ATP-dependent binding of NblA to ClpC was corroborated by in vitro pull-down assays. Introducing amino acid exchanges, we verified that the conserved N-terminal motif of NblA mediates the interaction with ClpC. Further results indicate that NblA binds phycobiliprotein subunits and ClpC simultaneously, thus bringing the proteins into close proximity. Altogether these results suggest that NblA may act as an adaptor protein that guides a ClpC.ClpP complex to the phycobiliprotein disks in the rods of phycobilisomes, thereby initiating the degradation process. PMID:18818204

  3. 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

  4. 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

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    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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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%

  10. 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

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    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

  11. Genome sequence of a recombinant brassica yellows virus infecting Chinese cabbage.

    Science.gov (United States)

    Lim, Seungmo; Yoo, Ran Hee; Igori, Davaajargal; Zhao, Fumei; Kim, Kil Hyun; Moon, Jae Sun

    2015-02-01

    RNA from a Chinese cabbage plant (Brassica campestris ssp. pekinensis) showing leaf malformation and mottling was labeled and hybridized to a DNA chip capable of detecting plant viruses and viroids. Probes specific for beet mild yellowing virus (BMYV) and beet western yellows virus (BWYV) yielded positive results, suggesting that the plant was infected by a polerovirus. Primers designed from the sequences of the positive probes were used to amplify and sequence one portion of the viral genome. This sequence showed a 90 % or greater identity to several poleroviruses, including BMYV, BWYV, beet chlorosis virus (BChV) and turnip yellows virus (TuYV). The complete genome sequence of the Chinese cabbage-infecting polerovirus consisted of 5,666 nt and was most closely related to brassica yellows virus (BrYV; 94 % identity). The virus was named BrYV-Cheongsong (BrYV-CS). However, ORF3, ORF4 and the 5' half of ORF5 of BrYV-CS were more closely related to those of TuYV, BWYV, BChV and BMYV than to those of BrYV. Interestingly, a recombination event (positions 3531-4819 in BrYV-CS) was detected when this sequence was aligned with those of BrYV and TuYV. This region showed the highest sequence identity to that of TuYV (94 % identity) and had greater than 93 % identity to those of BWYV, BChV and BMYV, but it shared only 81 % identity with that of BrYV. Taken together, the genomes of BrYV-CS and BrYV are closely related. However, the structural genes in the 3' half of the genome of BrYV-CS are more closely related to those of other poleroviruses. PMID:25352211

  12. 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.

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    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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. The Citrus Sanitation Center of Estación Experimental Agroindustrial Obispo Colombres, Tucumán, Argentina El Centro de Saneamiento de Citrus de la Estación Experimental Agroindustrial Obispo Colombres de Tucumán, Argentina

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    Beatriz E. Stein

    Full Text Available In October 2004, the Estación Experimental Agroindustrial Obispo Colombres (Tucumán, Argentina founded its Citrus Sanitation Center. The goal of this center is to establish and keep a group of the most important citrus varieties and rootstocks true to type and free of graft-transmissible pathogens. These will be used as primary sources of propagating material for citrus growers and researchers in northwestern Argentina. Mother trees of the main commercial citrus varieties were selected from the germplasm bank of the experiment station and were recovered through the standard procedure of shoot tip grafting (STG. Healthy plants are carefully and periodically indexed by biological, serological and molecular methods for tristeza, psorosis, exocortis, cachexia, citrus variegated chlorosis, citrus canker and huanglongbing. The Citrus Sanitation Center will maintain a supply of healthy propagation material and will continue a program initiated in 1966, consting in introducing, producing and releasing nucellar clones.La Estación Experimental Agroindustrial Obispo Colombres (EEAOC creó en el año 2004 el Centro de Saneamiento de Citrus (CSC para la ejecución de tareas de limpieza y diagnóstico de virus en cítricos. El objetivo de este centro es establecer y mantener un plantel de plantas madres cítricas, de variedades copa y portainjertos, de alta calidad genética y libre de plagas y enfermedades transmisibles por injerto. Este grupo de plantas se constituye como fuente primaria de material de propagación para productores, viveristas e investigadores del noroeste argentino. Las plantas madres de las principales variedades comerciales de cítricos se seleccionaron del banco de germoplasma de la EEAOC y se recuperaron por la técnica de microinjerto de ápices caulinares, procedimiento estándar utilizado en la limpieza de plantas cítricas. Periódicamente se verifica su sanidad por métodos biológicos, serológicos y moleculares para las

  18. Potential of MuS1 Transgenic Tobacco for Phytoremediation of the Urban Soils Contaminated with Cadmium

    Science.gov (United States)

    Kim, K. H.; Kim, Y. N.; Kim, S. H.

    2010-05-01

    Urban soils are prone to contamination by trace elements such as Cd, Cu, Pb and Zn. Phytoremediation is one of the attractive remediation methods for soils contaminated with trace elements due to its non-destructive and environmentally-friendly characteristic. Scientists have tried to find hyper-accumulator plants in nature or to develop transgenic plant through genetic engineering. This study was carried out to identify a potential of MuS1 transgenic tobacco for phytoremediation of the urban soils contaminated with Cd. MuS1 is known as a multiple stress related gene with several lines. The previous study using RT-PCR showed that the expression of MuS1 gene in tobacco plant induced tolerance to Cd stress. For this study, MuS1 transgenic tobacco and wild-type tobacco (control) were cultivated in a hydroponic system treated with Cd (0, 50, 100 and 200μM Cd) for 3 weeks. At harvest, both tobacco and nutrient solution were collected and were analyzed for Cd. Effect of Cd treatment on morphological change of the tobacco leaves was also observed by variable-pressure scanning electron microscopy (VP-SEM). The tolerance of MuS1 transgenic tobacco to Cd stress was better than that of wild-type tobacco at all Cd levels. Especially, wild-type tobacco showed chlorosis and withering with 200μM Cd treatment, whereas MuS1 transgenic tobacco gradually recovered from Cd damage. Wild-type tobacco accumulated more Cd (4.65mg per plant) than MuS1 transgenic tobacco (2.37mg per plant) with 200μM Cd treatment. Cd translocation rate from root to leaves was 81.8 % for wild-type tobacco compared to 37.1 % for MuS1 transgenic tobacco. Result of VP-SEM showed that the number of trichome in the leaves for wild-type tobacco increased in comparison with that for untreated samples after 3 weeks, while that for MuS1 transgenic tobacco was not changed by Cd treatment. Results showed that the mechanism of the recovery of the MuS1 tobacco plant was not by high level of Cd uptake and accumulation

  19. 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

  20. Effect of boron nutrition on American ginseng in field and in nutrient cultures.

    Science.gov (United States)

    Proctor, John T A; Shelp, Barry J

    2014-01-01

    Field and nutrient cultures of American ginseng (Panax quinquefolius L.) were used to establish foliar symptoms related to boron (B) concentration in leaves and soils, and to evaluate radish as a time-saving model system for B nutrition. Application of excess B, 8 kg/ha versus the recommended 1.5 kg/ha, to field plantings of 2-, 3-, and 4-yr-old American ginseng plants just prior to crop emergence caused, within 4 wk after crop emergence, leaf symptoms of chlorosis followed by necrosis starting at the tips and progressing along the margins. The B concentration in leaves of 2-4-yr-old plants receiving 1.5 kg/ha B was 30 μg/g dry mass compared to 460 μg/g dry mass where 8 kg/ha B was applied. Similarly, B concentration in soils receiving the lower B concentration was 1.8 μg/g dry mass and 2.2-2.8 μg/g dry mass where the higher B concentration was applied. Application of 8 kg/ha B reduced the dry yield of 3rd-yr roots by 20% from 2745 kg/ha to 2196 kg/ha and 4th-yr roots by 26% from 4130 kg/ha to 3071 kg/ha. Ginseng seedlings and radish were grown under greenhouse conditions in nutrient culture with four B concentrations ranging from 0 mg/L to 10 mg/L. At 5 mg/L and 10 mg/L ginseng and radish developed typical leaf B toxicity symptoms similar to those described above for field-grown plants. Increasing B in the nutrient solution from 0.5 mg/L to 10 mg/L decreased, in a linear fashion, the root and leaf dry mass of ginseng, but not radish. Given the many similarities of ginseng and radish to B utilization, radish might be used as a time-saving model system for the study of B, and other micronutrients, in the slow-growing perennial ginseng. PMID:24558314

  1. 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.

  2. Characterisation and performance evaluation of twenty accessions of sweet potato (Ipomoea batatas (L.) Lam.) in the coastal savannah agro-ecological zone of Ghana

    International Nuclear Information System (INIS)

    This study assessed the genetic diversity, using morphological and protein markers, as well as incidence of viral diseases among 20 accessions of sweet potato. Morphological analysis was carried out using 47 traits while protein analysis was performed with sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Sample plants collected from the field were tested for viruses using nitrocellulose membrane enzyme-linked immuno-sorbent assay (NCM-ELISA) and PCR for a DNA virus (Sweet potato Leaf curl virus). Scions from symptomatic plants were grafted onto Ipomoea setosa, a nearly universal indicator plant for sweet potato viruses, and leaves were tested using NCM-ELISA. From the cluster analysis, the accessions were grouped into two clusters at a genetic similarity index of 61.6%. The accessions ER001 and HMA2 were shown to be possible duplicates. Accession US 020 recorded the highest total root yield and harvest index of 56.32 t/ha and 57.11% respectively. Similarly, two pairs of accession SA/BNARI and UE 007 as well as HMA I and US 029 were identified as duplicates based on their protein banding patterns. While, three entries, LOCAL I, US 004 and UK/BNARI were also identified as a single entity based on their banding patterns for leaf and tuber proteins. Symptoms observed in the field varied from vein clearing, chlorosis, leaf reduction to stunting and the highest index of symptom severity for only diseased plants (ISSdp) was 3.63 recorded for US 029. The highest disease incidence (100%) was recorded at 11 WAP and 12 WAP. NCM-ELISA test detected eight viruses out of ten, with SA/BNARI exhibiting all the eight viruses. Mixed infections ranged from duplet to octaplet. The indicator plant I. setosa grafted with scions from sweet potato showed clear symptoms similar to those observed on the field. PCR test using SPG3/SPG4 primers detected SPLCV in the UK/BNARI accessions. Based on the morphological characters as well as response to virus infection, two

  3. Screening for sweet potato (Ipomoea batatas (L.)) viruses and their elimination using thermotheraphy-meristem tip culture technique

    International Nuclear Information System (INIS)

    Despite its high potential for food security, production of sweet potato is constrained by viruses which reduce yield by 90%. It is therefore essential to screen for, identify and eliminate these viruses in elite clones before dissemination to farmers. In this study, visual symptomatology and PCR-based techniques were used to identify sweet potato viruses. Visual symptomatology revealed virus associated symptoms ranging from vein clearing, interveinal chlorosis, chlorotic spots, upward curling on leaf edges, leaf narrowing and distortion, purpling, blistering, reduction of the leaf blades and general leaf yellowing in all 22 accessions grown on the field. Disease Incidence (DI) significantly (p≤0.05) varied between accessions with US003 having the lowest (20%) while ten accessions had 90% DI at the end of the study. Index of symptom severity of all plants (ISSap) ranged from 1.08±0.09 to 3.67 ±0.11 with VOTCR003 having the lowest suggesting that it is a moderately susceptible accession while VOTCR002 had the highest suggesting that it is susceptible to viral diseases. Contrarily, index of symptom severity of diseased plants (ISSdp) ranged from 2.00±0.25 to 3.75±0.32. The accession VOTCR002 had the highest ISSdp. Visual symptomatology showed that VOTCR002 had the highest DI, ISSap and ISSdp suggesting that it is highly susceptible to viral diseases. Ten severely infected accessions were tested for Sweet Potato leaf curl virus (SPLCV), Sweet Potato chlorotic stunt virus (SPCSV), Sweet potato feathery mottle virus (SPFMV) and Sweet Potato mild mottle virus (SPMMV) using PCR and RT-PCR techniques. RT-PCR did not amplify any of the virus genomes due to prolonged storage enzymes, In contrast, PCR detected SPLCV in 30% of the accessions. Plants infected with SPLCV were grown in the chamber at 35 degrees celsius for 4 weeks followed by meristem top culture. The regenerants were indexed after ten weeks for SPLCV. Fifty two percent (52.385 od the regenerants were

  4. Factors affecting in vitro seed germination and shoot multiplication of a pitcher plant (Nepenthes mirabilis (Lour. Druce

    Directory of Open Access Journals (Sweden)

    Tokhao, W

    2007-03-01

    Full Text Available Mature seeds of a pitcher plant (Nepenthes mirabilis (Lour. Druce were cultured in liquid and solid MS medium (Murashige and Skoog, 1962 supplemented with BA (6-benzyladenine at 1, 3 or 5 mg/l or withcoconut water (20% v/v. The cultures were incubated under light and dark conditions. Seeds germinated only under light incubation and BA supplemented to both types of media, and solid medium with 3 mg/l BAresulted the highest seed germination (26% with good development of seedlings. On the contrary, the addition of coconut water to the basal medium produced poor seed germination and seedling growth. Moreover,all cultures in liquid medium terminated their growth after 6 weeks of culture. Young seedlings were subsequently transferred to fresh media of the same treatments after 15 weeks of seed culture. Multipleshoots were proliferated in all levels of BA after 6 weeks of transferring and more shoots were produced as BA level was increased. However, at high BA level of 5 mg/l, rosetting of shoots occurred while lowering BA level to 3 mg/l, fewer shoots were produced but they were vigorous, larger shoots with complete leaves. Rootdevelopment finally occurred in all BA treatments except the addition of coconut water.To evaluate the potential of shoot multiplication in different strengths of MS macromutrient, two types of explants, viz. shoot explants and stem explants (both approx. 1.5 cm long from in vitro seedlings,were cultured on full-strength MS macronutrient medium, 1/2 MS, 1/4 MS and 1/8 MS medium. Following 16 weeks of culture, shoot production (number/ explant increased in both explant types as the macronutrientstrength decreased. However, when lowering to 1/8 MS, the fewest shoots were produced and exhibited nutrient deficiency of leaf chlorosis. The optimum strength of MS macronutrient for the maximumproduction of normal shoots with complete leaves was 1/2 MS medium while 1/4 MS medium produced the highest shoot number from stem explants but

  5. 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

  6. 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

  7. Soil and crop management experiments in the Laboratory Biosphere: an analogue system for the Mars on Earth(R) facility.

    Science.gov (United States)

    Silverstone, S; Nelson, M; Alling, A; Allen, J P

    2005-01-01

    During the years 2002 and 2003, three closed system experiments were carried out in the "Laboratory Biosphere" facility located in Santa Fe, New Mexico. The program involved experimentation of "Hoyt" Soy Beans, (experiment #1) USU Apogee Wheat (experiment #2) and TU-82-155 sweet potato (experiment #3) using a 5.37 m2 soil planting bed which was 30 cm deep. The soil texture, 40% clay, 31% sand and 28% silt (a clay loam), was collected from an organic farm in New Mexico to avoid chemical residues. Soil management practices involved minimal tillage, mulching, returning crop residues to the soil after each experiment and increasing soil biota by introducing worms, soil bacteria and mycorrhizae fungi. High soil pH of the original soil appeared to be a factor affecting the first two experiments. Hence, between experiments #2 and #3, the top 15 cm of the soil was amended using a mix of peat moss, green sand, humates and pumice to improve soil texture, lower soil pH and increase nutrient availability. This resulted in lowering the initial pH of 8.0-6.7 at the start of experiment #3. At the end of the experiment, the pH was 7.6. Soil nitrogen and phosphorus has been adequate, but some chlorosis was evident in the first two experiments. Aphid infestation was the only crop pest problem during the three experiments and was handled using an introduction of Hyppodamia convergens. Experimentation showed there were environmental differences even in this 1200 cubic foot ecological system facility, such as temperature and humidity gradients because of ventilation and airflow patterns which resulted in consequent variations in plant growth and yield. Additional humidifiers were added to counteract low humidity and helped optimize conditions for the sweet potato experiment. The experience and information gained from these experiments are being applied to the future design of the Mars On Earth(R) facility (Silverstone et al., Development and research program for a soil

  8. 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.

  9. Development and characterization of an oat TILLING-population and identification of mutations in lignin and β-glucan biosynthesis genes

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    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. 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

    Directory of Open Access Journals (Sweden)

    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

  11. Seqüenciamento e variabilidade do fragmento genômico de Xylella fastidiosa amplificado pelos iniciadores RST31/33 Sequencing and variability of the Xylella fastidosa - specific genomic fragment amplified by the primer pair RST 31/33

    Directory of Open Access Journals (Sweden)

    Adriane Wendland

    2003-06-01

    Full Text Available Xylella fastidiosa é agente causal de diversas doenças de importância econômica como a clorose variegada dos citros (Citrus spp. (CVC, mal de Pierce da videira (Vitis vinifera, escaldadura da ameixeira (Prunus salicina e requeima do cafeeiro (Coffea arabica. A seqüência nucleotídica do fragmento genômico, específico de X. fastidiosa, amplificado pelo par de iniciadores RST31/33 foi determinada para 38 isolados de citros e para isolados de videira, cafeeiro e ameixeira objetivando avaliar o nível de polimorfismo entre isolados e a identidade genômica do fragmento. Não foi observado polimorfismo de seqüência nucleotídica entre isolados de citros, mas foi detectado polimorfismo entre isolados de citros e de videira, cafeeiro e ameixeira. A presença do sítio de clivagem RsaI, que distingue isolados de citros e videira de isolados de ameixeira e outras espécies arbóreas, foi identificada em um isolado de ameixeira proveniente dos EUA mas não em outro proveniente do Brasil.Xylella fastidiosa causes several plant diseases of economic importance such as citrus (Citrus spp. variegated chlorosis (CVC, Pierce's disease of grapevine (Vitis vinifera and leaf scorch of plum (Prunus salicina and coffee (Coffea arabica. The nucleotide sequence of the genomic fragment, specific to Xylella fastidosa, amplified by the pair of primers RST 31/33, was determined for 38 isolates from citrus and for isolates from grapevine, coffee and plum in order to assess the level of sequence polymorphism of this fragment among isolates, as well as its genomic identity. Sequence polymorphism was not observed among isolates from citrus, but was detected among isolates from citrus and from grapevine, coffee and plum. The presence of a RsaI restriction site, which distinguishes isolates from citrus and grapevine from plum and other arboreal species, was identified in a North American isolate from plum but not in a Brazilian one.

  12. 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.

  13. Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

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    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

  14. 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

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    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.

  15. 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

  16. 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

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    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

  17. 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.

  18. 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

  19. Complete Genome Sequence of Mulberry Vein Banding Associated Virus, a New Tospovirus Infecting Mulberry.

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    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.

  20. 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

  1. Genetic linkage maps of 'Pêra' sweet orange and 'Cravo' mandarin with RAPD markers Mapas genéticos de ligação de laranja 'Pêra' e tangerina 'Cravo' utilizando marcadores RAPD

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    Roberto Pedroso de Oliveira

    2004-02-01

    Full Text Available The objective of this work was to construct linkage maps of 'Pêra' sweet orange [Citrus sinensis (L. Osbeck] and 'Cravo' mandarin (Citrus reticulata Blanco using RAPD markers and the pseudo-testcross strategy. The parents were chosen according to the resistance/susceptibility to citrus variegate chlorosis (CVC. The segregation of 176 markers was analyzed in 94 progeny of F1 hybrids, which were obtained from controlled crossings. The linkage map of 'Pêra' sweet orange had 117 markers defined by 12 linkage groups, which spanned 612.1 cM. Only six markers could not be linked to the linkage group and 48.7% of the markers showed segregation distortion. The linkage map of 'Cravo' mandarin had 51 markers defined by 12 linkage groups, which spanned 353.3 cM. Only two markers did not link to the groups and 15.7% showed segregation distortion. The construction of linkage maps is relevant to future mapping studies of the inheritance of CVC, citrus canker and leprosis.O objetivo deste trabalho foi elaborar mapas de ligação de laranja 'Pêra' [Citrus sinensis (L. Osbeck] e tangerina 'Cravo' (Citrus reticulata Blanco utilizando marcadores RAPD e a estratégia pseudo-testcross. Os parentais foram escolhidos tomando-se por base o nível de resistência/suscetibilidade à clorose variegada dos citros (CVC. A segregação de 176 marcadores foi analisada em uma progênie de 94 híbridos F1, obtidos por meio de cruzamentos controlados. O mapa de ligação de laranja 'Pêra' apresentou 117 marcadores distribuídos em 12 grupos de ligação, totalizando 612,1 cM. Apenas seis marcadores não se ligaram a algum dos grupos de ligação e 48,7% deles apresentaram segregação distorcida. O mapa de ligação de tangerina 'Cravo' apresentou 51 marcadores distribuídos em 12 grupos de ligação, totalizando 353,3 cM. Apenas dois marcadores apresentaram-se desligados e 15,7% deles apresentaram segregação distorcida. A elaboração de mapas de ligação dessas

  2. 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

  3. 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.

  4. 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

  5. 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

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    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

  6. Integrating microarray analysis and the soybean genome to understand the soybeans iron deficiency response

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    Cannon Steven

    2009-08-01

    Full Text Available Abstract Background Soybeans grown in the upper Midwestern United States often suffer from iron deficiency chlorosis, which results in yield loss at the end of the season. To better understand the effect of iron availability on soybean yield, we identified genes in two near isogenic lines with changes in expression patterns when plants were grown in iron sufficient and iron deficient conditions. Results Transcriptional profiles of soybean (Glycine max, L. Merr near isogenic lines Clark (PI548553, iron efficient and IsoClark (PI547430, iron inefficient grown under Fe-sufficient and Fe-limited conditions were analyzed and compared using the Affymetrix® GeneChip® Soybean Genome Array. There were 835 candidate genes in the Clark (PI548553 genotype and 200 candidate genes in the IsoClark (PI547430 genotype putatively involved in soybean's iron stress response. Of these candidate genes, fifty-eight genes in the Clark genotype were identified with a genetic location within known iron efficiency QTL and 21 in the IsoClark genotype. The arrays also identified 170 single feature polymorphisms (SFPs specific to either Clark or IsoClark. A sliding window analysis of the microarray data and the 7X genome assembly coupled with an iterative model of the data showed the candidate genes are clustered in the genome. An analysis of 5' untranslated regions in the promoter of candidate genes identified 11 conserved motifs in 248 differentially expressed genes, all from the Clark genotype, representing 129 clusters identified earlier, confirming the cluster analysis results. Conclusion These analyses have identified the first genes with expression patterns that are affected by iron stress and are located within QTL specific to iron deficiency stress. The genetic location and promoter motif analysis results support the hypothesis that the differentially expressed genes are co-regulated. The combined results of all analyses lead us to postulate iron inefficiency in

  7. Comparative genomic characterization of citrus-associated Xylella fastidiosa strains

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    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

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.)

  13. 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

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    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.

  14. 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

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    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.

  15. 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

  16. 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

  17. 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.

  18. Impact of radionuclides on formation of structure of plants of polluted areas of the Semipalatinsk test sites territory

    International Nuclear Information System (INIS)

    Full text: Scales of dozes provoking damages of plants cover wide range of values. Lethal doze of acute irradiation for herbaceous plants fluctuates from 600 till 75 000 R. Radiosensitivity of plants depends on numerous cytological and genetic indicators, biological and chemical composition of plants, peculiarities of physiological processes. Ionising irradiation provokes decrease of accretion, loss of reproductive functions and sterility of pollen, delay or complete oppression of blooming, significant delay of growth. It was revealed that teratological transformations of meadow plants occur more often. Morphological and anatomical transformations of overground organs of Lepidium latifolium, Melilotus albus, Berteroa incana, Calamagrostis epigeios, Potentilla virgata, Odontites serotina, Linaria altaica, Rosa laxa were revealed in mesophyte communities (com.) of forb + Phragmites australis + Elytrigia repens (1998), com. of Calamagrostis epigeios + Galatella biflora + Sanguisorba offlcinalis (1998), com. of Elytrigia repens + Inula britannica (1999) under PED of gamma irradiation of 100-150 μR/H. Comparative analysis of morphological structure of 8 plants (annuals, biennials, perennials, dwarf semishrabs, shrubs) from the polluted and control plots revealed following changes: inhibition of growth (Berteroa incana,. Melilotus albus, Koch ia sieversiana, Rosa laxa); coiled stem (Phlomis tuberosa); change of direction of stem growth (Lepidium latifolium, Melilotus albus, Phlomis tuberosa); shortening of internodes (Rosa laxa); change of type of branching of stem (Rosa laxa) and dichotomy of stem (Lepidium latifolium); congestence of offshoots (Rosa laxa); change of section of stem (Melilotus albus, Phlomis tuberosa); change of shape of blade (Lepidium latifolium, Kochia sieversiana); change of dimensions of blade (Rosa laxa, Lepidium latifolium, Kochia sieversiana); chlorosis of leafs (Rosa laxa, Lepidium latifolium); wrinkled leafs (Lepidium latifolium); formation

  19. 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.

  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. Geostical analysis of spatial dynamics of Citrus Variegated Chlorossis Análise da dinâmica espacial da Clorose Variegada dos Citros através da Geoestatística

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    SÉRGIO R. ROBERTO

    2002-11-01

    Full Text Available The spatial dynamics of Citrus Variegated Chlorosis (CVC was studied in a five-year old commercial orchard of 'Valencia' sweet orange (Citrus sp. trees, located in the northern region of the state of São Paulo, Brazil. One thousand trees were assessed in 25 rows of 40 trees, planted at 8 x 5 m spacing. Disease incidence data were taken beginning in March 1994 and ending in January 1996, at intervals of four to five months. Disease aggregation was observed through the dispersion index analysis (Ib, which was calculated by dividing the area into quadrants. CVC spatial dynamics was examined using semivariogram analysis, which revealed that the disease was aggregated in the field forming foci of 10 to 14 m. For each well-fitted model, a kriging map was created to better visualize the distribution of the disease. The spherical model was the best fit for the data in this study. Kriging maps also revealed that the incidence of CVC increased in periods during which the trees underwent vegetative growth, coinciding with greater expected occurrence of insect vectors of the bacterium in the field.A dinâmica espacial da Clorose Variegada dos Citros (CVC foi estudada em um pomar comercial de laranja (Citrus sinensis 'Valência' de cinco anos de idade, localizada na região norte do Estado de São Paulo, Brasil. Foram avaliadas 1.000 plantas em uma quadra disposta em 25 ruas por 40 plantas por rua, plantada no espaçamento 8 x 5 m. As avaliações (presença ou ausência da doença iniciaram-se em março de 1994 e estenderam-se até janeiro de 1996, em um intervalo de quatro a cinco meses entre uma e outra. A agregação da doença foi observada por meio da análise do índice de dispersão (Ib, o qual foi calculado dividindo-se a área em quadrantes. A dinâmica espacial da CVC foi avaliada por análises de semivariogramas e apresentou padrão agregado da doença no campo formando reboleiras de 10 a 14 m. Para cada modelo ajustado, um mapa de krigagem foi

  2. 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

  3. 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

  4. 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

  5. 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

  6. Citrus sinensis leaf petiole and blade colonization by Xylella fastidiosa: details of xylem vessel occlusion Colonização de pecíolo e folha de Citrus sinensis por Xylella fastidiosa

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    Eduardo Alves

    2009-04-01

    Full Text Available Citrus variegated chlorosis (CVC, caused by Xylella fastidiosa, is an important disease of citrus in Brazil. X. fastidiosa is restricted to xylem vessels of plants and knowledge regarding xylem colonization is still limited. Our goal was to verify how this bacterium colonizes and spreads within xylem vessels of sweet orange Citrus sinensis cv. Pêra. Petioles and pieces of leaf blades from naturally infected plant exhibiting characteristic symptoms were prepared for light microscopy (LM, scanning electron microscopy (SEM, transmission electron microscopy (TEM and immunogold labeling (IGL. Petioles from healthy plants were used as control. IGL results, using an antibody against wall hemicelluloses, revealed that the pit membrane of vessels was altered. Bacterial cells were observed in the pit between adjacent vessels. Results support the contention that X. fastidiosa produces cellulases to reach adjacent vessels. SEM revealed that colonization of sweet orange started with X. fastidiosa cells attaching to the xylem wall, followed by an increase in the number of bacterial cells, the production of fibrous material, and finally vessel occlusion by biofilm composed of copious amounts of amorphous material, strands and cells. Phenolic materials, hyperplasia and hypertrophy were noticed in leaves with gummy material. Xylem vessels frequently contained an unknown needle-like, crystallized matter blocking the vessel.A clorose variegada dos citrus (CVC, causada por uma bactéria restrita ao xilema (Xylella fastidiosa, é uma importante doença de citros no Brasil, entretanto, pouco se sabe sobre a colonização dos vasos do xilema pela bactéria. O objetivo deste trabalho foi estudar como X. fastidiosa invade os vasos adjacentes do xilema e algumas das alterações expressas por plantas de laranja Pêra. Foram coletadas 15 amostras de pecíolos e áreas das folhas de plantas com sintomas característicos da doença, as quais foram preparadas para

  7. 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

  8. 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

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    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'.

  9. 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

  10. Broiler litter and inorganic nitrogen fertilizers influence on earliness and yield on strawberry and cabbage

    International Nuclear Information System (INIS)

    Author.Comparison of broiler litter (BL) rates to inorganic nitrogen fertilizers was studied during 1994-1995 as to its effect on earliness and yield of strawberry and cabbage grown on a calcareous soil. Strawberry (Frag aria x ananassa Duch.cv.Oso Grande) was grown using BL at rates which supplied 100 (BL1) or 200 (BL2) Kg N/ha, ammonium nitrate or nitrogen+trace elements applied at 150 Kg N/ha in six equally split applications throughout the growing season. Crop yield was higher (P0.05) under the litter treated plots especially the BL2 rate. Leaf Fe was comparable among treatments (P>0.05) and no Fe chlorosis symptoms were observed, even though the soil is calcareous. Residual soil nitrate-nitrogen was comparable (P>0.05) among all the treatments with the ammonium nitrate and the BL2 having the highest values, indicating that BL at 200 Kg N/ha apparently released an amount of N equivalent to that from the 150 Kg N/ha of ammonium nitrate. Available soil P (water soluble), although comparable among treatments (P>0.05), was higher under the BL treated plots especially at the 200 Kg N/ha rate reflecting the P content of the manure. It is recommended to apply BL at a rate of 200 Kg N/ha to fertilize strawberry over the use of inorganic N fertilizers at similar rates. O-S-Cross cabbage (Brassica oleracea var. Capitata) was tested using the same rates of BL described previously, ammonium nitrate or nitrogen+trace elements at 125 Kg N/ha split as 25 Kg N/ha early in the season, 50 Kg N/ha just before heading, and 50 Kg N/ha at heading. Total yield and marketable yield were higher under the inorganic treated plots than under BL (P2. The higher yields under the inorganic N fertilizer treated plots were also reflected in leaf nitrate-nitrogen. Leaf blade P was comparable (P>0.05) among all treatments indicating a high soil P level at the beginning of all treatments before heading (P>0.05) and at heading, where as at first harvest it was higher (P<0.05) under the nitrogen

  11. 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

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    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.

  12. HOSPEDANTES DE Ralstonia solanacearum EN PLANTACIONES DE BANANO Y PLÁTANO EN COLOMBIA HOSTS OF Ralstonia solanacearum ON BANANA AND PLANTAIN PLANTATIONS IN COLOMBIA

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    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.

  13. Agrogeology today

    Science.gov (United States)

    Kerek, Barbara; Kuti, Laszlo; Vatai, Jozsef

    2010-05-01

    the soil-(soil forming sediment)-parent rock-groundwater or "soil-parent rock-bedrock" system aimed at the prevention and elimination of harmful effects. 5. Investigation of the geological aspects of water regulation and irrigation as well as their impact on the environment. 6. Definition, examination and characterisation of the real soil forming geological sequence. In Hungary the actual agrogeological investigations were launched by the agricultural reambulation of geological mapping data. During the early 1980s the so-called BFK-method was elaborated to the agrogeological investigation of these areas still used today. The main aspect of this method is that apart from the common geological sampling of the boreholes samples are also taken from the top- and subsoil (horizon 1), the soil forming sediment or parent material (horizon 2), the fluctuation zone of the groundwater (horizon 3) as well as from the zone permanently below the groundwater level (horizon 4) and the groundwater itself (Figure 2). These samples undergo detailed laboratory analyses. The comparative evaluation of the derived results allows making different agrogeological conclusions. During the period elapsed from the early 1980s the survey of the pilot areas allowed us investigating among others the agrogeological relationships of salinisation, acidification, excess water risk, erosion, and trace element regime as well as vine chlorosis.

  14. 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.

  15. Multiplicação de gemas axilares de Acacia mearnsii de wild. Sob diferentes meios de cultura Multiplication of axillary shoots in Acacia mearnsii de wild. Under different culture medium

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    Ruter Disarz

    2009-08-01

    /1, with and without activated charcoal. It was used a randomized experimental design, with five, seven and four replicates, with four explants per replicate. The evaluations were performed after 30 days, through the counting of the numbers of leafs and axillary shoots and the presence of callus and chlorosis. Among the media used in the original composition, the MS promoted the best multiplication of axillary shoots (3,7 buds/explants on the thirtieth day of culture. Among the MS medium macro-nutrient concentrations, the dilution to 3/4 of the original concentration with the addition of activated carbon promoted the best responses for the multiplication of black wattle axillary shoots (7,7 buds/explant after 60 days of culture.

  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. 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

  18. 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

  19. 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.

  20. 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

  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.

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    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. ASİDİK YAGIŞLARIN TRİTİCUM VULGARE ( BUGDAY ve ZEA • • • • • MA YS SACCHARA TA (MISIR BITKILERINE ETKILERI

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    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

  3. 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

  4. 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.

  5. 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

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    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.

  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. Apple Rootstock New Variety Chistock #1%苹果砧木新品种中砧1号

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    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

  8. 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.

  9. Detection and partial characterization of an isolate of Groundnut ringspot virus in Solanum sessiliflorum Detecção e caracterização parcial de um isolado de Groundnut ringspot virus em Solanum sessiliflorum

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    ALESSANDRA J. BOARI

    2002-06-01

    Full Text Available The cubiu (Solanum sessiliflorum fruit, originating in the Amazon basin, is commonly used in that region for food, medicine, and cosmetics. In an experimental culture of cubiu, in order to evaluate its adaptation to conditions in the Northern region of the state of Rio de Janeiro, it was observed plants with mosaic symptoms. A cubiu plant was collected and analyzed to identify the etiological agent. After mechanical passage through a local lesion host, a host range test was performed. The virus induced chlorotic local lesions in Chenopodium quinoa, necrotic local lesions in Gomphrena globosa, mosaic in S. sessiliflorum, leaf and stem necrosis in tomato (Lycopersicon esculentum 'Rutgers', mosaic and leaf distortion in Datura stramonium and Physalis floridana, and necrotic local lesions followed by systemic necrosis and plant death in four Nicotiana species. Electron microscopic observations of ultra thin sections from infected cubiu leaves showed the presence of spheroidal, membrane-bound particles typical of tospovirus species. Analysis of the nucleocapsid protein from concentrated virus particles indicated the presence of a 28 kDa protein. RT-PCR was performed after total RNA extraction from infected IPA-6 tomato leaves. A fragment of approximately 0,8 kbp corresponding to the N gene was amplified, cloned and sequenced. The N protein from the cubiu isolate was 95% homologous to the Groundnut ringspot virus (GRSV protein, and no more than 85% homologous to those from Zucchini lethal chlorosis virus (ZLCV and Chrysanthemun stem necrosis virus (CSNV, Tomato spotted wilt virus (TSWV, and Tomato chlorotic spot virus (TCSV. This is the first report of the occurrence of GRSV (or any other plant virus in cubiu.O cubiu (Solanum sessiliflorum, originário da Amazônia, é um fruto utilizado como alimento, medicamento e cosmético. Em um plantio experimental de cubiu, para a avaliação da sua adaptação nas condições da região Norte do Estado do Rio

  10. 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