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Sample records for bacterial leaf spot

  1. Show us your spots! Researchers need samples of bacterial leaf spots on celery, cilantro, parsley, and other crops.

    Science.gov (United States)

    Since 2002, a severe leaf spot disease on parsley has occurred throughout central coastal California and particularly in Monterey County. Three different bacterial pathogens (Pseudomonas syringae pv. apii, P. syringae pv. coriandricola and an organism very closely related to P. viridiflava) have bee...

  2. Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae.

    Science.gov (United States)

    Kim, Da-Ran; Gang, Gun-Hye; Jeon, Chang-Wook; Kang, Nam Jun; Lee, Sang-Woo; Kwak, Youn-Sig

    2016-08-01

    Strawberry bacterial angular leaf spot (ALS) disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August), the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%). To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

  3. Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae

    Directory of Open Access Journals (Sweden)

    Da-Ran Kim

    2016-08-01

    Full Text Available Strawberry bacterial angular leaf spot (ALS disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August, the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%. To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

  4. Molecular characterization of Xanthomonas strains responsible for bacterial leaf spot of tomato in Ethiopia

    Science.gov (United States)

    Bacterial spot of tomato (BST) is a major constraint to tomato production in Ethiopia and many other countries leading to significant crop losses. In the present study, using pathogenicity tests, sensitivity to copper and streptomycin, and multilocus sequence analysis, a diverse group of Xanthomonas...

  5. Evaluation of indigenous bacterial strains for biocontrol of the frogeye leaf spot of soya bean caused by Cercospora sojina.

    Science.gov (United States)

    Simonetti, E; Carmona, M A; Scandiani, M M; García, A F; Luque, A G; Correa, O S; Balestrasse, K B

    2012-08-01

    Assessment of biological control of Cercospora sojina, causal agent of frogeye leaf spot (FLS) of soya bean, using three indigenous bacterial strains, BNM297 (Pseudomonas fluorescens), BNM340 and BNM122 (Bacillus amyloliquefaciens). From cultures of each bacterial strain, cell suspensions and cell-free supernatants were obtained and assayed to determine their antifungal activity against C. sojina. Both mycelial growth and spore germination in vitro were more strongly inhibited by bacterial cell suspensions than by cell-free supernatants. The Bacillus strains BNM122 and BNM340 inhibited the fungal growth to a similar degree (I ≈ 52-53%), while cells from P. fluorescens BNM297 caused a lesser reduction (I ≈ 32-34%) in the fungus colony diameter. The foliar application of the two Bacillus strains on soya bean seedlings, under greenhouse conditions, significantly reduced the disease severity with respect to control soya bean seedlings and those sprayed with BNM297. This last bacterial strain was not effective in controlling FLS in vivo. Our data demonstrate that the application of antagonistic bacteria may be a promising and environmentally friendly alternative to control the FLS of soya bean.   To our knowledge, this is the first report of biological control of C. sojina by using native Bacillus strains. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  6. Association analysis of bacterial leaf spot resistance and SNP markers derived from expressed sequence tags (ESTs) in lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is a devastating disease of lettuce worldwide. Since there are no chemicals available for effective control of the disease, host-plant resistance is highly desirable to protect lettuce production. A total of 179 lettuce ge...

  7. Science Letters:Differentiation of xanthomonads causing the bacterial leaf spot of poinsettia in China from the pathotype strain of Xanthomonas axonopodis pv. Poinsettiicola

    Institute of Scientific and Technical Information of China (English)

    LI Bin; XIE Guan-lin; SWINGS J.

    2005-01-01

    In October 2003, a new bacterial disease with symptoms similar to those caused by Xanthomonas axonopodis pv.poinsettiicola was observed on poinsettia leaves at a flower nursery in Zhejiang Province of China. Three Xanthomonas strains were isolated from infected plants and classified as X. axonopodis. They were differentiated from the pathotype strain LMG849 of X. axonopodis pv. poinsettiicola causing bacterial leaf spot of poinsettia by comparison of pathogenicity, substrate utilization and BOX-PCR genomic fingerprints.

  8. 草莓细菌叶斑病病原鉴定%Bacterial Pathogen Identification of Leaf Spot on Strawberry

    Institute of Scientific and Technical Information of China (English)

    米楠

    2011-01-01

    Traditional bacterial identification measures by appearance observation and physiology bio-chemical tests and the mordern bacterial identification measures by 16S rDNA technique were used to identify the bacterial pathogen of leaf spot on strawberry. The results showed that the strain could use glucose,lactose,maltose,sucrose,D-Trehalose,starch,mannitol,inositol,L-Valine and L-Proline. The strain was positive for nitrate reduction, arginine cihydrolase and oxidase reaction,but negative for fat hydrolysis,starch hydrolysis and gelatin hydrolysis. At last,the strain was identified as Xanthomonas fragariae.%采用形态观察、生理生化特性测试等传统的细菌鉴定方法和16srDNA碱基序列测定等现代的细菌鉴定方法鉴定草莓细菌叶斑病菌株。结果表明:该菌株可利用的碳源有葡萄糖、乳糖、麦芽糖、蔗糖、D-海藻糖、淀粉、甘露醇、肌醇、L-缬氨酸、L-精氨酸。硝酸盐还原试验为阳性,淀粉水解阴性,明胶水解阴性,油脂水解阴性,精氨酸双水解酶阳性,接触酶阳性;鉴定该菌株为草莓黄单孢菌(Xanthomonas fragariae)。

  9. Klebsiella pneumoniae subsp.pneumoniae引起云南省香蕉细菌性叶斑病%A New Bacterial Leaf Spot of Banana Caused by Klebsiella pneumoniae subsp.pneumoniae in Yunnan Province of China

    Institute of Scientific and Technical Information of China (English)

    陈丽华; 黄敏; 何鹏飞; Hon-hing HO; 吴毅歆; 何月秋

    2016-01-01

    To identify the pathogen causing a new bacterial leaf spot on banana (Musa sapientum L.) in Xinping County,Yunnan Province of China,the bacterium was isolated from the infected banana plant and identified by cultural and morphological studies,pathogenicity test,physiological and biochemical detection as well as sequences analyses of gyrB,16S rDNA and rpoB genes.The results showed that the leaf spot disease was caused by Klebsiella pneumoniae subsp.pneumoniae.The pathogen could infect banana fruit,pseudo-stem and leaf.Black spots appeared on diseased pseudo-stems within 3 days after inoculation and they enlarged lengthwise in both directions,causing massive brown necrosis of the internal tissues within the pseudo-stem in 7 days.This is the first report of K.pneumoniae subsp.pneumoniae causing leaf spot of banana plants in the world.%为明确一种新的香蕉(Musa sapientum)细菌性叶斑病病原菌,以云南省新平县香蕉园区发现的一种新病害为供试材料,通过分离培养、形态观察、致病性测定、生理生化试验和gyrB,16S rDNA和rpoB基因片段分析,对病原菌进行了鉴定.该病由克雷伯氏肺炎球菌肺炎亚种(Klebsiella pneumoniae subsp.pneumoniae)引起,病菌可侵染香蕉叶片、假茎和果实.茎干被病原菌侵入3d后即可出现黑色小斑点,在接种部位附近呈上下方向蔓延趋势,7d后茎干上出现大面积棕色坏死,内部组织褐变.本文在世界上首次报道克雷伯氏肺炎球菌肺炎亚种可侵染香蕉植株,引起香蕉细菌性叶斑病.

  10. Mutation breeding in sunflower for resistance to alternaria leaf spot

    OpenAIRE

    de Marcelo Oliveira F.; Tulmann Augusto Neto; Regina Leite M.V.B.C.; Vania Castiglioni B.R.; Arias C.A.A.

    2004-01-01

    Genetic variability for resistance to Alternarla leaf spot disease (Alternaria helianthi) can be induced by radiation or chemical mutagens. The objectives of this study were to create genetic variability in cultivated sunflower and to select lines resistant to Alternaria leaf spot. In the first experiment, sunflower seeds of the genotype HA BR 104 were irradiated with 150 and 165 Gy of gamma rays. Seeds were sown in the field at the Embrapa Soybean experimental station, in Londrina, PR, Brazi...

  11. Leaf Spot of Yam Caused by Pseudophloeosporella dioscoreae in Korea.

    Science.gov (United States)

    Hong, Sung Kee; Kim, Wan Gyu; Lee, Young Kee; Choi, Hyo Won; Choi, Kyung Jin; Lee, Sang Yeob

    2010-03-01

    Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.

  12. FaRXf1: a locus conferring resistance to angular leaf spot caused by Xanthomonas fragariae in octoploid strawberry

    Science.gov (United States)

    Angular leaf spot caused by Xanthomonas fragariae is the only major bacterial disease of cultivated strawberry (Fragaria ×ananassa). While this disease may cause reductions of up to 8 % of marketable yield in Florida winter annual production, no resistant cultivars have been commercialized. Wild acc...

  13. Multilocus sequence typing of Pseudomonas syringae sensu lato confirms previously described genomospecies and permits rapid identification of P. syringae pv. coriandricola and P. syringae pv. apii causing bacterial leaf spot on parsley.

    Science.gov (United States)

    Bull, Carolee T; Clarke, Christopher R; Cai, Rongman; Vinatzer, Boris A; Jardini, Teresa M; Koike, Steven T

    2011-07-01

    Since 2002, severe leaf spotting on parsley (Petroselinum crispum) has occurred in Monterey County, CA. Either of two different pathovars of Pseudomonas syringae sensu lato were isolated from diseased leaves from eight distinct outbreaks and once from the same outbreak. Fragment analysis of DNA amplified between repetitive sequence polymerase chain reaction; 16S rDNA sequence analysis; and biochemical, physiological, and host range tests identified the pathogens as Pseudomonas syringae pv. apii and P. syringae pv. coriandricola. Koch's postulates were completed for the isolates from parsley, and host range tests with parsley isolates and pathotype strains demonstrated that P. syringae pv. apii and P. syringae pv. coriandricola cause leaf spot diseases on parsley, celery, and coriander or cilantro. In a multilocus sequence typing (MLST) approach, four housekeeping gene fragments were sequenced from 10 strains isolated from parsley and 56 pathotype strains of P. syringae. Allele sequences were uploaded to the Plant-Associated Microbes Database and a phylogenetic tree was built based on concatenated sequences. Tree topology directly corresponded to P. syringae genomospecies and P. syringae pv. apii was allocated appropriately to genomospecies 3. This is the first demonstration that MLST can accurately allocate new pathogens directly to P. syringae sensu lato genomospecies. According to MLST, P. syringae pv. coriandricola is a member of genomospecies 9, P. cannabina. In a blind test, both P. syringae pv. coriandricola and P. syringae pv. apii isolates from parsley were correctly identified to pathovar. In both cases, MLST described diversity within each pathovar that was previously unknown.

  14. Epidemiology of light leaf spot (Pyrenopeziza brassicae) on winter oilseed rape (Brassica napus) = De epidemiologie van 'light leaf spot' (Pyrenopeziza brassicae) in winterkoolzaad (Brassica napus)

    NARCIS (Netherlands)

    Gilles, T.

    2000-01-01

    Forecasts of the severity of light leaf spot of winter oilseed rape are needed to help growers with their decisions on fungicide applications at times when sprays are needed to control light leaf spot, but the disease is difficult to diagnose. A thorough understanding of stages in

  15. ldentification and Control Methods of Eggplant Bacterial Wilt, Soft Rot, Necrotic Leaf Spot, Mo-saic Virus, Root-knot Ne-matode Disease, Sun-scald, Leaf Scorch and Dehiscent Fruit%茄子青枯病、软腐病、细菌性褐斑病、病毒病、根结线虫病、日灼病、叶烧病和裂果的识别与防治

    Institute of Scientific and Technical Information of China (English)

    郑丹丹; 张杨林

    2012-01-01

    介绍了茄子青枯病、软腐病、细菌性褐斑病、病毒病、根结线虫病、日灼病、叶烧病和裂果的危害症状、发病特点,并从农业措施、化学防治等方面总结了各病害的综合防治方法。%The symptom and disease characteristics of eggplant bacterial wilt, soft rot, necrotic leaf spot, mosaic virus, root-knot nematode disease, sunscald, leaf scorch and dehiscent fruit were in-troduced. Then the integrated control methods were put forward, which con-tained measures of agricultural control, chemical control and so on.

  16. Inhibition of Xanthomonas fragariae, Causative Agent of Angular Leaf Spot of Strawberry, through Iron Deprivation

    Directory of Open Access Journals (Sweden)

    Peter Henry

    2016-10-01

    Full Text Available In commercial production settings, few options exist to prevent or treat angular leaf spot of strawberry, a disease of economic importance and caused by the bacterial pathogen Xanthomonas fragariae (Xfr. In the process of isolating and identifying Xfr bacteria from symptomatic plants, we observed growth inhibition of Xfr by bacterial isolates from the same leaf macerates. Identified as species of Pseudomonas and Rhizobium, these isolates were confirmed to suppress growth of Xfr in agar overlay plates and in microtiter plate cultures, as did our reference strain Pseudomonas putida KT2440. Screening of a transposon mutant library of KT2440 revealed that disruption of the biosynthetic pathway for the siderophore pyoverdine resulted in complete loss of Xfr antagonism, suggesting iron competition as a mode of action. Antagonism could be replicated on plate and in culture by addition of purified pyoverdine or by addition of the chelating agents tannic acid and dipyridyl, while supplementing the medium with iron negated the inhibitory effects of pyoverdine, tannic acid and dipyridyl. When co-inoculated with tannic acid onto strawberry plants, Xfr’s ability to cause foliar symptoms was greatly reduced, suggesting a possible opportunity for iron-based management of angular leaf spot. We discuss our findings in the context of ‘nutritional immunity’, the idea that plant hosts restrict pathogens access to iron, either directly, or indirectly through their associated microbiota.

  17. Tan spot - the most harmful wheat leaf disease in Latvia

    Directory of Open Access Journals (Sweden)

    Biruta Bankina

    2012-12-01

    Full Text Available Tan spot (Pyrenophora tritici-repentis is one of the most important wheat diseases in Latvia. Significant spreading of this disease was observed from 1998. Field experiments were carried out at the Research and Training Farm "Peterlauki" of the Latvia University of Agriculture, during 1998-2003. Development of diseases was observed on 14 winter wheat varieties, dynamics of development was investigated on 'Donskaja polukarlikovaja' and 'Stava'. Assessments of the disease severity were carried out on the upper three leaves each week from the start of stem elongation to full ripening. Tan spot was observed at the stage of stem elongation in 2003, and only after flowering in 1999. Increase of the disease severity was slow until stage of milk ripeness, and only in late stages of wheat development sharp increase of the disease was observed. Total rate of infection (through the session of vegetation was very slow (0,01-0,19, but during ripening rate achieved 0,5-0,6. The main reason of so unequal development of the disease seems changes in amount of infection sources. Other possible reason of rapid increase of the disease development is the relationship between leaf age and susceptibility to the disease. Further research is necessary for better understanding of tan spot life cycle.

  18. Characterization and mapping of a spotted leaf mutant in rice (Oryza sativa

    Directory of Open Access Journals (Sweden)

    Xue Xu

    2014-06-01

    Full Text Available Spotted leaf mutant belongs to a class of mutants that can produce necrotic lesions spontaneously in plants without any attack by pathogens. These mutants have no beneficial effect on plant productivity but provide a unique opportunity to study programmed cell death in plant defense responses. A novel rice spotted leaf mutant (spl30 was isolated through low-energy heavy ion irradiation. Lesion expression was sensitive to light and humidity. The spl30 mutant caused a decrease in chlorophyll and soluble protein content, with marked accumulation of reactive oxygen species (ROS around the lesions. In addition, the spl30 mutant significantly enhanced resistance to rice bacterial blight (X. oryzae pv. oryzae from China (C1-C7. The use of SSR markers showed that the spl30 gene was located between markers XSN2 and XSN4. The genetic distance between the spl30 gene and XSN2 and between spl30 and XSN4 was 1.7 cM and 0.2 cM, respectively. The spl30 gene is a new gene involved in lesion production and may be related to programmed cell death in rice. The ability of this mutant to confer broad resistance to bacterial blight provides a model for studying the interaction between plants and pathogenic bacteria.

  19. Genetic dissection of novel QTLs for resistance to leaf spots and Tomato spotted wilt virus in peanut (Arachis hypogaea L.)

    Science.gov (United States)

    Peanut is an import crop, economically and nutritiously, but high production cost is a serious challenge to peanut farmers as exemplified by chemical spray to control foliar diseases such as leaf spots and thrips, the vectors of tomato spotted wilt virus (TSWV). The objective of this research was to...

  20. Leaf Spot and Stem Rot on Wilford Swallowwort Caused by Stemphylium lycopersici in Korea.

    Science.gov (United States)

    Hong, Sung Kee; Choi, Hyo Won; Lee, Young Kee; Shim, Hong Sik; Lee, Sang Yeob

    2012-12-01

    In June 2012, leaf spot and stem rot were observed on Wilford Swallowwort plants grown in Cheonan, Korea. Three fungal isolates obtained from the diseased leaves and stems were identified as Stemphylium lycopersici, based on morphological, cultural, and molecular characteristics and pathogenicity. This is the first report of leaf spot and stem rot on Wilford Swallowwort caused by S. lycopersici.

  1. Effects of formulation and surfactant on control of early leaf spot of peanut with tebuconazole

    Science.gov (United States)

    Prior to 1997, control of early leaf spot with the DMI fungicide tebuconazole, applied in a block of 4 mid-season applications scheduled between 2 applications of chlorothalonil, was similar to a full-season program with chlorothalonil. Periodically since 1997, control of early leaf spot with tebuc...

  2. Resistance in winter barley against Ramularia leaf spot

    DEFF Research Database (Denmark)

    Hjortshøj, Rasmus Lund

    Ramularia leaf spot is an emerging disease in barley caused by R. collo-cygni. At present little is known about the resistance mechanisms carried out by the host plant to avoid disease development. Nor is the lifecycle of the fungus or its populations structure fully understood. To gain insight...... into these aspects four experiments were set up; (1) a mapping experiment aiming at identifying QTL’s controlling disease levels under field conditions was conducted in two winterbarley populations. (2) a toxin assay testing the parental lines used in the mapping populations for response to Rubellin D was developed....... (3) microarray analysis of transcriptional response in barley to inoculation with R. collo-cygni was carried out, and finally the (4) population genetic structure of R. collo-cygni was assessed by AFLP and gene sequencing. Based on these experiments interaction was compared to the interactions of C...

  3. First Report of Fusarium subglutinans Causing Leaf Spot Disease on Cymbidium Orchids in Korea.

    Science.gov (United States)

    Han, Kyung-Sook; Park, Jong-Han; Back, Chang-Gi; Park, Mi-Jeong

    2015-09-01

    In 2006~2010, leaf spot symptoms, that is, small, yellow spots that turned into dark brown-to-black lesions surrounded by a yellow halo, were observed on Cymbidium spp. in Gongju, Taean, and Gapyeong in Korea. A Fusarium species was continuously isolated from symptomatic leaves; in pathogenicity testing, isolates caused leaf spot symptoms consisting of sunken, dark brown lesions similar to the original ones. The causal pathogen was identified as Fusarium subglutinans based on morphological and translation elongation factor 1-alpha sequence analyses. This is the first report of F. subglutinans as the cause of leaf spot disease in Cymbidium spp. in Korea.

  4. Classification of Cotton Leaf Spot Disease Using Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Prof. Sonal P. Patil

    2014-05-01

    Full Text Available In order to obtain more value added products, a product quality control is essentially required Many studies show that quality of agriculture products may be reduced from many causes. One of the most important factors of such quality plant diseases. Consequently, minimizing plant diseases allows substantially improving quality of the product Suitable diagnosis of crop disease in the field is very critical for the increased production. Foliar is the major important fungal disease of cotton and occurs in all growing Indian cotton regions. In this paper I express Technological Strategies uses mobile captured symptoms of Cotton Leaf Spot images and categorize the diseases using support vector machine. The classifier is being trained to achieve intelligent farming, including early detection of disease in the groves, selective fungicide application, etc. This proposed work is based on Segmentation techniques in which, the captured images are processed for enrichment first. Then texture and color Feature extraction techniques are used to extract features such as boundary, shape, color and texture for the disease spots to recognize diseases.

  5. Retrieving leaf area index from SPOT4 satellite data

    Directory of Open Access Journals (Sweden)

    M. Aboelghar

    2010-12-01

    Full Text Available A research project was conducted as collaboration between the National Authority for Remote Sensing and Space Sciences (NARSS in Egypt and the Institute of Remote Sensing Applications (IRSA, Chinese Academy of Sciences. The objective of this study is to generate normalized difference vegetation index (NDVI–leaf area index (LAI statistical inversion models for three rice varieties planted in Egypt (Giza-178, Sakha-102, and Sakha-104 using the data of two rice growing seasons. Field observations were carried out to collect LAI field measurements during 2008 and 2009 rice seasons. The SPOT4 satellite data acquired in rice season of 2008 and 2009 conjunction with field observations dates were used to calculate the vegetation indices values. Statistical analyses were performed to confirm the assumptions of inversion modeling for plant variables and to get reliable models that fit the inversion relationship between LAI and NDVI. The inversion process resulted in three NDVI–LAI models adequate to predict LAI with 95% confidence for the three different rice varieties. The accuracy of the generated models ranged between 50% in the case of Sakha-104 and 82% in the case of Giza-178. LAI maps were produced from NDVI imageries based on the generated models.

  6. Molecular Diagnostics in the Mycosphaerella Leaf Spot Disease Complex of Banana and for Radopholus similis

    NARCIS (Netherlands)

    Arzanlou, M.; Kema, G.H.J.; Waalwijk, C.; Carlier, I.; Vries, de P.M.; Guzmán, M.; Araya Vargas, M.; Helder, J.; Crous, P.W.

    2009-01-01

    Mycosphaerella leaf spots and nematodes threaten banana cultivation worldwide. The Mycosphaerella disease complex involves three related ascomycetous fungi: Mycosphaerella fijiensis, M. musicola and M. eumusae. The exact distribution of these three species and their disease epidemiology remain

  7. Molecular Diagnostics in the Mycosphaerella Leaf Spot Disease Complex of Banana and for Radopholus similis

    NARCIS (Netherlands)

    Arzanlou, M.; Kema, G.H.J.; Waalwijk, C.; Carlier, I.; Vries, de P.M.; Guzmán, M.; Araya Vargas, M.; Helder, J.; Crous, P.W.

    2009-01-01

    Mycosphaerella leaf spots and nematodes threaten banana cultivation worldwide. The Mycosphaerella disease complex involves three related ascomycetous fungi: Mycosphaerella fijiensis, M. musicola and M. eumusae. The exact distribution of these three species and their disease epidemiology remain uncle

  8. Severity of banana leaf spot in an intercropping system in two cycles of banana Prata Ana

    OpenAIRE

    Valdeir Dias Gonçalves; Silvia Nietsche; Marlon Cristian Toledo Pereira; Manoel Xavier de Oliveira Júnior; Roberto Célio Antunes Júnior; Carlos Ruggiero

    2008-01-01

    Prata Ana is the most planted banana cultivar in northern Minas Gerais, Brazil. It is however susceptible to several pathogens. This study was carried out to evaluate the disease severity of banana leaf spot in the Prata Ana cv. in the first and second cycle under six different planting systems. The randomized block experimental design was used with six treatments and four replications. lit an evaluation of the severity of banana leaf spot, no disease symptoms were found on Thap Maeo and Caip...

  9. Control of angular leaf spot on dry beans with fungicides and its effect on plant production

    OpenAIRE

    Deman, Luis Alfredo Raue; Maringoni, Antonio Carlos [UNESP

    2012-01-01

    The angular leaf spot of dry bean caused by the fungus Phaeoisairopsis griseola is a very important disease on dry bean crops in Brazil. In propitious weather conditions, susceptible cultivars have significant losses due to this disease. In these conditions, fungicide usage is an important step for angular leaf spot management. Since the effects of this method of control on plant physiology are not known, this study had the following objectives: a) Verify the action of fungicide in physiologi...

  10. First Record of Alternaria simsimi Causing Leaf Spot on Sesame (Sesamum indicum L.) in Korea.

    Science.gov (United States)

    Choi, Young Phil; Paul, Narayan Chandra; Lee, Hyang Burm; Yu, Seung Hun

    2014-12-01

    Leaf spot disease was observed in sesame (Sesamum indicum L.) during 2009 and 2010 in Korea. The pathogen was identified as Alternaria simsimi based on morphological and cultural characteristics. The morphological identification was well supported by phylogenetic analysis of the ribosomal DNA-internal transcribed spacer region. A. simsimi isolates caused spot symptoms on leaves and stems of sesame plants 2 wk after artificial inoculation, which were similar to those observed in the field. This is the first record of leaf spot disease in Korea caused by A. simsimi.

  11. Genetic parameters and selection for resistance to bacterial spot in recombinant F6 lines of Capsicum annuum

    Directory of Open Access Journals (Sweden)

    Messias Gonzaga Pereira

    2009-01-01

    Full Text Available This study aimed to advance generations and select superior sweet pepper genotypes with resistance tobacterial spot, using the breeding method Single Seed Descent (SSD based on the segregating population derived from thecross between Capsicum annuum L. UENF 1421 (susceptible, non-pungent and UENF 1381 (resistant, pungent. Thesegregating F3 generation was grown in pots in a greenhouse until the F5 generation. The F6 generation was grown in fieldconditions. The reaction to bacterial spot was evaluated by inoculation with isolate ENA 4135 of Xanthomonas campestris pv.vesicatoria, based on a score scale and by calculating the area under the disease progress curve (AUDPC. The presence orabsence of capsaicin was also assessed. Eighteen F6 lines were bacterial leaf spot-resistant. Since no capsaicin was detectedin the F6 lines 032, 316, 399, 434, and 517, these will be used in the next steps of the sweet pepper breeding program.

  12. Genetic Dissection of Novel QTLs for Resistance to Leaf Spots and Tomato Spotted Wilt Virus in Peanut (Arachis hypogaea L.)

    Science.gov (United States)

    Pandey, Manish K.; Wang, Hui; Khera, Pawan; Vishwakarma, Manish K.; Kale, Sandip M.; Culbreath, Albert K.; Holbrook, C. Corley; Wang, Xingjun; Varshney, Rajeev K.; Guo, Baozhu

    2017-01-01

    Peanut is an important crop, economically and nutritiously, but high production cost is a serious challenge to peanut farmers as exemplified by chemical spray to control foliar diseases such as leaf spots and thrips, the vectors of tomato spotted wilt virus (TSWV). The objective of this research was to map the quantitative trait loci (QTLs) for resistance to leaf spots and TSWV in one recombinant inbred line (RIL) mapping population of “Tifrunner × GT-C20” for identification of linked markers for marker-assisted breeding. Here, we report the improved genetic linkage map with 418 marker loci with a marker density of 5.3 cM/loci and QTLs associated with multi-year (2010–2013) field phenotypes of foliar disease traits, including early leaf spot (ELS), late leaf spot (LLS), and TSWV. A total of 42 QTLs were identified with phenotypic variation explained (PVE) from 6.36 to 15.6%. There were nine QTLs for resistance to ELS, 22 QTLs for LLS, and 11 QTLs for TSWV, including six, five, and one major QTLs with PVE higher than 10% for resistance to each disease, respectively. Of the total 42 QTLs, 34 were mapped on the A sub-genome and eight mapped on the B sub-genome suggesting that the A sub-genome harbors more resistance genes than the B sub-genome. This genetic linkage map was also compared with two diploid peanut physical maps, and the overall co-linearity was 48.4% with an average co-linearity of 51.7% for the A sub-genome and 46.4% for the B sub-genome. The identified QTLs associated markers and potential candidate genes will be studied further for possible application in molecular breeding in peanut genetic improvement for disease resistance. PMID:28197153

  13. Genetic Analysis and Gene Mapping of Light Brown Spotted Leaf Mutant in Rice

    Institute of Scientific and Technical Information of China (English)

    FENG Bao-hua; YANG Yang; SHI Yong-feng; LIN Lu; CHEN Jie; WEI Yan-lin; Hei LEUNG

    2013-01-01

    A light brown spotted-leaf mutant of rice was isolated from an ethane methyl sulfonate (EMS)induced IR64 mutant bank.The mutant,designated as Ibsl1 (light brown spotted-leaf 1),displayed light brown spot in the whole growth period from the first leaf to the flag leaf under natural summer field conditions.Agronomic traits including plant height,growth duration,number of filled grains per panicle,seed-setting rate and 1000-grain weight of the mutant were significantly affected.Genetic analysis showed that the mutation was controlled by a single recessive gene,tentatively named Ibsl1(t),which was mapped to the short arm of chromosome 6.By developing simple sequence repeat (SSR) markers,the gene was finally delimited to an interval of 130 kb between markers RM586 and RM588.The Ibsl1(t) gene is likely a novel rice spotted-leaf gene since no other similar genes have been identified near the chromosomal region.The genetic data and recombination populations provided will facilitate further fine-mapping and cloning of the gene.

  14. Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce.

    Science.gov (United States)

    Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

    2012-10-01

    The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009-2010 crop cycle. Total bacterial populations averaged between 10(5) and 10(6) per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial 'core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment.

  15. Effects of cherry leaf spot on photosynthesis in tart cherry 'Montmorency' foliage.

    Science.gov (United States)

    Gruber, B R; Kruger, E L; McManus, P S

    2012-07-01

    Results described here span a total of three field seasons and quantitatively depict the effects of an economically important fungal pathogen (Blumeriella jaapii) on tart cherry (Prunus cerasus 'Montmorency') leaf physiology. For the first time, leaf photosynthesis, stomatal conductance (g(s)), maximum ribulose-1,5-bisphosphate carboxylation rate (V(cmax)), and maximum electron transport (J(max)) were measured as functions of visible cherry leaf spot disease (CLS) severity. Defined as the proportion of chlorotic and necrotic tissue per leaf, CLS severity was estimated from leaves of mature 'Montmorency' trees in 2007, 2008, and 2009. Briefly, as visible disease severity increased, all of the leaf-level physiological parameters decreased significantly (P tart cherry leaves due to CLS appears to be mediated through disproportionately large perturbations in g(s), V(cmax), and J(max). These findings offer a new perspective on the amount of damage that this serious disease can inflict.

  16. Reaction of the BASE 120 lines to angular leaf spot in Puerto Rico

    Science.gov (United States)

    Common bean (Phaseolus vulgaris L.) is limited by diseases such as Angular leaf spot (ALS), caused by Phaeoisariopsis griseola (Sacc.) Ferraris sin. Pseudocercospora griseola (Sacc.) Crous & U. Braun. The virulence of Phaeoisariopis griseola isolate ALS-9029-JD2 from Juana Diaz, PR was determined by...

  17. Control of Cherry Leaf Spot and Cherry Fruit Fly at Sour Cherry

    Directory of Open Access Journals (Sweden)

    Maria BOROVINOVA

    2015-06-01

    Full Text Available The investigations were made in the experimental sour cherry orchard from the Institute of Agriculture, Kyustendil, Bulgaria, during the period 2010-2014, in order to compare conventional and integrated sour cherry protection against cherry leaf spot and cherry fruit fly. Two variants were investigated, with two different treatment approaches for the control of cherry leaf spot and cherry fruit fly. Variant 1 – cherry leaf spot was controlled by protective treatments with dodin and tebuconazole + trifloxystrobin and cherry fruit fly was controlled by treatments with deltametrin and thiacloprid, independently of density. Variant 2 - cherry leaf spot was controlled by post-infection (curative treatments with tebuconazole + trifloxystrobin and cherry fruit fly was controlled by treatments based on biological threshold: 10-11 cherry fruit fly females caught in traps up to the moment for chemical treatment. It was established that Blumeriella japii can be successfully controlled by post-infection treatments and by this the number of insecticide treatments was reduced. The treatments against cherry fruit fly can be avoided or reduced when the attack control is based on the biological threshold established in the studied area.

  18. Differential Expression of R-genes to Associate Leaf Spot Resistance in Cultivated Peanut

    Science.gov (United States)

    Breeding for acceptable levels of Early (ELS) or Late Leaf Spot (LLS) resistance in cultivated peanut has been elusive due to extreme variability of plant response in the field and the proper combinations of resistance (R)-genes in any particular peanut line. R-genes have been shown to be involved ...

  19. Cercospora leaf spot: monitoring and managing fungicide resistance in populations of Cercospora beticola in Michigan

    Science.gov (United States)

    Cercospora leaf spot (CLS, Cercospora beticola) is the most serious foliar disease of sugarbeet in Michigan and Ontario.Management of CLS depends on timely fungicide applications, disease forecasting prediction models and the use of CLS resistant sugar beet varieties. Fungicides have a dominant role...

  20. Fine genetic mapping of target leaf spot resistance gene cca-3 in cucumber, Cucumis sativus L

    Science.gov (United States)

    The target leaf spot (TLS) is a very important fungal disease in cucumber. In this study, we conducted fine genetic mapping of a recessively inherited resistance gene, cca-2 against TLS with 1,083 F2 plants derived from the resistant cucumber inbred line D31 and the susceptible line D5. Initial mapp...

  1. Septoria-like pathogens causing leaf and fruit spot of pistachio

    NARCIS (Netherlands)

    Crous, P.W.; Quaedvlieg, W.; Sarpkaya, K.; Can, C.; Erkiliç, A.

    2013-01-01

    Several species of Septoria are associated with leaf and fruit spot of pistachio (Pistacia vera), though their identity has always been confused, making identification problematic. The present study elucidates the taxonomy of the Septoria spp. associated with pistachio, and distinguishes four specie

  2. Effect of climate change on Alternaria leaf spot of rocket salad and black spot of basil under controlled environment.

    Science.gov (United States)

    Pugliese, M; Cogliati, E; Gullino, M L; Garibaldi, A

    2012-01-01

    Plant responses to elevated CO2 and temperature have been much studied in recent years, but effects of climate change on pathological responses are still largely unknown. The pathosystems rocket (Eruca vesicaria subsp. sativa)--Alternaria leaf spot (Alternaria japonica) and basil (Ocimum basilicum)--black spot (Colletotrichum gloeosporioides) were chosen as models to assess the potential impact of increased CO2 and temperature on disease incidence and severity under controlled environment. Potted plants were grown in phytotrons under 4 different simulated climatic conditions: (1) standard temperature (ranging from 18 degrees to 22 degrees C) and standard CO2 concentration (400 ppm); (2) standard temperature and elevated CO2 concentration (800 ppm); (3) elevated temperature (ranging from 22 degrees to 26 degrees C, 4 degrees C higher than standard) and standard CO2 concentration; (4) elevated temperature and CO2 concentration. Each plant was inoculated with a spore suspension containing 1 x 10(5) cfu/ml of the pathogen. Disease incidence and severity were assessed 14 days after inoculation. Increasing CO2 to 800 ppm showed a clear increment in the percentage of Alternaria leaf spot on rocket leaves compared to standard conditions. Basil plants grown at 800 ppm of CO2 showed increased black spot symptoms compared to 400 ppm. Disease incidence and severity were always influenced by the combination of rising CO2 and increased temperature, compared to standard conditions (400 ppm of CO2 - 22 degrees C). Considering the rising concentrations of CO2 and global temperature, we can assume that this could increase the severity of Alternaria japonica on rocket and Colletotrichum gloeosporioides on basil.

  3. Genetic control of the angular leaf spot reaction in common bean leaves and pods

    Directory of Open Access Journals (Sweden)

    Jerônimo Constantino Borel

    2011-12-01

    Full Text Available Information about genetic control of plant reaction to pathogens is essential in plant breeding programs focusing resistance. This study aimed to obtain information about genetic control of the angular leaf spot reaction in leaves and pods from common bean (Phaseolus vulgaris L. line ESAL 686. This line was crossed with cultivars Jalo EEP 558 (resistant, Cornell 49-242 (resistant and Carioca MG (susceptible. Generations F1, F2 and backcrosses (BC11 and BC21 were obtained. In the dry season (2009, parents and respective populations were evaluated for angular leaf spot reaction under field conditions. Disease severity was evaluated on leaves and pods using diagrammatic scales. Severity scores were obtained and mean and variance genetic components were estimated for both. Segregation of F2 generation was analyzed for some crosses. Different genes control angular leaf spot reaction in leaves and pods. Mean and variance components showed predominance of additive effects. Heritability was high, however, was greater on pods than on leaves which indicated that leaf reaction is more influenced by the environment.

  4. Isolation and characterization of a spotted leaf 32 mutant with early leaf senescence and enhanced defense response in rice

    Science.gov (United States)

    Sun, Liting; Wang, Yihua; Liu, Ling-long; Wang, Chunming; Gan, Ting; Zhang, Zhengyao; Wang, Yunlong; Wang, Di; Niu, Mei; Long, Wuhua; Li, Xiaohui; Zheng, Ming; Jiang, Ling; Wan, Jianmin

    2017-01-01

    Leaf senescence is a complex biological process and defense responses play vital role for rice development, their molecular mechanisms, however, remain elusive in rice. We herein reported a rice mutant spotted leaf 32 (spl32) derived from a rice cultivar 9311 by radiation. The spl32 plants displayed early leaf senescence, identified by disintegration of chloroplasts as cellular evidence, dramatically decreased contents of chlorophyll, up-regulation of superoxide dismutase enzyme activity and malondialdehyde, as physiological characteristic, and both up-regulation of senescence-induced STAY GREEN gene and senescence-associated transcription factors, and down-regulation of photosynthesis-associated genes, as molecular indicators. Positional cloning revealed that SPL32 encodes a ferredoxin-dependent glutamate synthase (Fd-GOGAT). Compared to wild type, enzyme activity of GOGAT was significantly decreased, and free amino acid contents, particularly for glutamate and glutamine, were altered in spl32 leaves. Moreover, the mutant was subjected to uncontrolled oxidative stress due to over-produced reactive oxygen species and damaged scavenging pathways, in accordance with decreased photorespiration rate. Besides, the mutant showed higher resistance to Xanthomonas oryzae pv. Oryzae than its wild type, coupled with up-regulation of four pathogenesis-related marker genes. Taken together, our results highlight Fd-GOGAT is associated with the regulation of leaf senescence and defense responses in rice. PMID:28139777

  5. Phylogenetic and Morphological Identification of the Novel Pathogen of Rheum palmatum Leaf Spot in Gansu, China.

    Science.gov (United States)

    Wang, Yan; Charkowski, Amy O; Zeng, Cuiyun; Zhu, Tiantian; Wang, Huizhen; Chen, Honggang

    2016-06-01

    A new leaf spot disease was observed on leaves of Rheum palmatum (Chinese rhubarb) in Northwest China (Gansu Province) starting in 2005. A Septoria-like fungus was isolated and completion of Koch's postulates confirmed that the fungus was the casual agent of the leaf spot disease. Morphology and molecular methods were combined to identify the pathogen. The fungus produced conidiomata pycnidia and the conidia were 2~5 septate, 61.2~134.1 µm in length and 3.53~5.3 µm in width, which is much larger than the known Spetoria species that infects Polygonaceae species. Phylogenic analysis of the internal transcribed spacer region confirmed that this Spetoria-like fungus is within the Spetoria genus but distinct from known Spetoria species. Together, these morphological and phylogenetic data support that the R. palmatum infecting Spetoria strain is a newly-described plant pathogenic species.

  6. Disease variation and chemical control of Ramularia leaf spot in sugar beet

    DEFF Research Database (Denmark)

    Thach, Tine; Munk, Lisa; Hansen, Anne Lisbet

    2013-01-01

    Data from 1999 to 2009 on Ramularia leaf spot caused by Ramularia beticola in sugar beet showed that it was a serious disease in sugar beet in 5 out of 11 seasons. The severity and significance of the disease was found to vary depending on events with precipitation, particularly in two specific...... weeks in July and September. Several fungicides were found to give effective control, and positive net yield responses were found in 9 out of 11 seasons. The average sugar yield response varied in individual years between 0.7 and 2.2 t ha−1. High levels of control of Ramularia leaf spot was obtained...... in field trials, a semi-field trial and an in vitro test using the compounds pyraclostrobin, epoxiconazole, difenoconazole and propiconazole. Dose response trials with epoxiconazole from two seasons showed both reduced efficacy and yield responses from low doses. They also proved that the optimal input...

  7. Characterization and Genetic Analysis of a Novel Rice Spotted-leaf Mutant HM47 with Broad-spectrum Resistance to Xanthomonas oryzae pv.oryzae(F)

    Institute of Scientific and Technical Information of China (English)

    Bao-Hua Feng; Yang Yang; Yong-Feng Shi; Hai-Chao Shen; Hui-Mei Wang; Qi-Na Huang; Xia Xu

    2013-01-01

    A stable inherited rice spotted-leaf mutant HM47 derived from an EMS-induced IR64 mutant bank was identified.The mutant expressed hypersensitive response (HR)-like symptoms throughout its whole life from the first leaf to the flag leaf,without pathogen invasion.Initiation of the lesions was induced by light under natural summer field conditions.Expression of pathogenesis-related genes including PAL,PO-C1,POX22.3 and PBZ1 was enhanced significantly in association with cell death and accumulation of H2O2 at and around the site of lesions in the mutant in contrast to that in the wild-type (WT).Disease reaction to Xanthomonas oryzae pv.oryzae from the Philippines and China showed that HM47 is a broad-spectrum disease-resistant mutant with enhanced resistance to multiple races of bacterial blight pathogens tested.An F2 progeny test showed that bacterial blight resistance to race HB-17 was cosegregated with the expression of lesions.Genetic analysis indicated that the spotted-leaf trait was controlled by a single recessive gene,tentatively named splHM47,flanked by two insertion/deletion markers in a region of approximately 74 kb on the long arm of chromosome 4.Ten open reading frames are predicted,and all of them are expressed proteins.Isolation and validation of the putative genes are currently underway.

  8. Yield, market quality, and leaf spots partial resistance of interspecific peanut progenies

    Directory of Open Access Journals (Sweden)

    Taís de Moraes Falleiro Suassuna

    2015-08-01

    Full Text Available Development of leaf spots resistant runner peanut cultivars is one of the major demands in Brazil. In the 2009/10 crop season, 12 pre-breeding progenies (LPM were selected out of 380 plants of an interspecific BC1 F3 population for leaf spots resistance and agronomic traits. In the 2010/11, the 12 LPMs were evaluated for leaf spots resistance, without fungicide sprays. The recurrent parent (susceptible control and all LPMs were susceptible; partial resistant segregating plants were selected. Some progenies had yield, pod and seed shape similar to the control. The 12, and the 5 LPMs selected in the 2011/12 and 2012/13 crop seasons, respectively, were evaluated under appropriate disease management. Differences were detected for pod yield and weight of 100 seeds. Seed/pod weight ratio, oil content and oleic/linoleic ratio were similar to the control. Individual plants were selected for pod yield and market quality. Variability detected in the first backcross generation for partial resistance and agronomic traits will be useful.

  9. Comparative QTL Mapping of Resistance to Gray Leaf Spot in Maize Based on Bioinformatics

    Institute of Scientific and Technical Information of China (English)

    SHI Li-yu; LI Xin-hai; HAO Zhuan-fang; XIE Chuan-xiao; JI Hai-lian; L(U) Xiang-ling; ZHANG Shi-huang; PAN Guang-tang

    2007-01-01

    The integration QTL map for gray leaf spot resistance in maize was constructed by compiling a total of 57 QTLs available with genetic map IBM2 2005 neighbors as reference.Twenty-six "real QTLs" and seven consensus QTLs were identified by refining these 57 QTLs using overview and meta-analysis approaches.Seven consensus QTLs were found on chromosomes 1.06,2.06,3.04,4.06,4.08,5.03,and 8.06,and the map coordinates were 552.53,425.72,279.20,368.97,583.21,308.68 and 446.14 cM,respectively.Using a synteny conservation approach based on comparative mapping between the maize genetic map and rice physical map,a total of 69 rice and maize resistance genes collected from websites Gramene and MaizeGDB were projected onto the maize genetic map IBM2 2005 neighbors,and 2(Rgene32,ht1),4(Rgene5,rp3,scmv2,wsm2),and 4(ht2,Rgene6,Rgene8 and Rgene7)positional candidate genes were found in three consensus QTLs on chromosomes 2.06,3.04,and 8.06,respectively.The results suggested that the combination of meta-analysis of gray leaf spot in maize and sequence homologous comparison between maize and rice could be an efficient strategy for identifying major QTLs and corresponding candidate genes for the gray leaf spot.

  10. Metabolic Response of Strawberry (Fragaria x ananassa) Leaves Exposed to the Angular Leaf Spot Bacterium (Xanthomonas fragariae).

    Science.gov (United States)

    Kim, Min-Sun; Jin, Jong Sung; Kwak, Youn-Sig; Hwang, Geum-Sook

    2016-03-09

    Plants have evolved various defense mechanisms against biotic stress. The most common mechanism involves the production of metabolites that act as defense compounds. Bacterial angular leaf spot disease (Xanthomonas fragariae) of the strawberry (Fragaria x ananassa) has become increasingly destructive to strawberry leaves and plant production. In this study, we examined metabolic changes associated with the establishment of long-term bacterial disease stress using UPLC-QTOF mass spectrometry. Infected leaves showed decreased levels of gallic acid derivatives and ellagitannins, which are related to the plant defense system. The levels of phenylalanine, tryptophan, and salicylic acid as precursors of aromatic secondary metabolites were increased in inoculated leaves, whereas levels of coumaric acid, quinic acid, and flavonoids were decreased in infected plants, which are involved in the phenylpropanoid pathway. In addition, phenylalanine ammonia-lyase (PAL) activity, a key enzyme in the phenylpropanoid pathway, was decreased following infection. These results suggest that long-term bacterial disease stress may lead to down-regulation of select molecules of the phenylpropanoid metabolic pathway in strawberry leaves. This approach could be applied to explore the metabolic pathway associated with plant protection/breeding in strawberry leaves.

  11. Spatial modelling of rice yield losses in Tanzania due to bacterial leaf blight and leaf blast in a changing climate

    NARCIS (Netherlands)

    Duku, Confidence; Sparks, Adam H.; Zwart, Sander J.

    2016-01-01

    Rice is the most rapidly growing staple food in Africa and although rice production is steadily increasing, the consumption is still out-pacing the production. In Tanzania, two important diseases in rice production are leaf blast caused by Magnaporthe oryzae and bacterial leaf blight caused by

  12. Molecular variability analyses of Apple chlorotic leaf spot virus capsid protein

    Indian Academy of Sciences (India)

    T Rana; V Chandel; Y Kumar; R Ram; V Hallan; A A Zaidi

    2010-12-01

    The complete sequences of the coat protein (CP) gene of 26 isolates of Apple chlorotic leaf spot virus (ACLSV) from India were determined. The isolates were obtained from various pome (apple, pear and quince) and stone (plum, peach, apricot, almond and wild Himalayan cherry) fruit trees. Other previously characterized ACLSV isolates and Trichoviruses were used for comparative analysis. Indian ACLSV isolates among themselves and with isolates from elsewhere in the world shared 91–100% and 70–98% sequence identities at the amino acid and nucleotide levels, respectively. The highest degree of variability was observed in the middle portion with 9 amino acid substitutions in contrast to the N-terminal and C-terminal ends, which were maximally conserved with only 4 amino acid substitutions. In phylogenetic analysis no reasonable correlation between host species and/or geographic origin of the isolates was observed. Alignment with capsid protein genes of other Trichoviruses revealed the TaTao ACLSV peach isolate to be phylogenetically closest to Peach mosaic virus, Apricot pseudo chlorotic leaf spot virus and Cherry mottle leaf virus. Recombination analysis (RDP3 ver.2.6) done for all the available ACLSV complete CP sequences of the world and Indian isolates indicate no significant evidence of recombination. However, one recombination event among Indian ACLSV-CP isolates was detected. To the best of our knowledge, this is the first report of complete CP sequence variability study from India and also the first evidence of homologous recombination in ACLSV.

  13. A single gene controls leaf background color in caladium (Araceae) and is tightly linked to genes for leaf main vein color, spotting and rugosity

    Science.gov (United States)

    Cao, Zhe; Sui, Shunzhao; Yang, Qian; Deng, Zhanao

    2017-01-01

    Modern cultivated caladiums (Caladium×hortulanum) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem, which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar ‘Miss Muffet’ and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem. Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F, but is tightly linked to three loci (S, V and RLF) controlling leaf spotting, main vein color, and rugosity in caladium. A linkage map that consists of four loci controlling major caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in caladium and in the Araceae family. The information gained in this study will be very useful for caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world. PMID:28101369

  14. Predicting favorable conditions for early leaf spot of peanut using output from the Weather Research and Forecasting (WRF) model.

    Science.gov (United States)

    Olatinwo, Rabiu O; Prabha, Thara V; Paz, Joel O; Hoogenboom, Gerrit

    2012-03-01

    Early leaf spot of peanut (Arachis hypogaea L.), a disease caused by Cercospora arachidicola S. Hori, is responsible for an annual crop loss of several million dollars in the southeastern United States alone. The development of early leaf spot on peanut and subsequent spread of the spores of C. arachidicola relies on favorable weather conditions. Accurate spatio-temporal weather information is crucial for monitoring the progression of favorable conditions and determining the potential threat of the disease. Therefore, the development of a prediction model for mitigating the risk of early leaf spot in peanut production is important. The specific objective of this study was to demonstrate the application of the high-resolution Weather Research and Forecasting (WRF) model for management of early leaf spot in peanut. We coupled high-resolution weather output of the WRF, i.e. relative humidity and temperature, with the Oklahoma peanut leaf spot advisory model in predicting favorable conditions for early leaf spot infection over Georgia in 2007. Results showed a more favorable infection condition in the southeastern coastline of Georgia where the infection threshold were met sooner compared to the southwestern and central part of Georgia where the disease risk was lower. A newly introduced infection threat index indicates that the leaf spot threat threshold was met sooner at Alma, GA, compared to Tifton and Cordele, GA. The short-term prediction of weather parameters and their use in the management of peanut diseases is a viable and promising technique, which could help growers make accurate management decisions, and lower disease impact through optimum timing of fungicide applications.

  15. Predicting favorable conditions for early leaf spot of peanut using output from the Weather Research and Forecasting (WRF) model

    Science.gov (United States)

    Olatinwo, Rabiu O.; Prabha, Thara V.; Paz, Joel O.; Hoogenboom, Gerrit

    2012-03-01

    Early leaf spot of peanut ( Arachis hypogaea L.), a disease caused by Cercospora arachidicola S. Hori, is responsible for an annual crop loss of several million dollars in the southeastern United States alone. The development of early leaf spot on peanut and subsequent spread of the spores of C. arachidicola relies on favorable weather conditions. Accurate spatio-temporal weather information is crucial for monitoring the progression of favorable conditions and determining the potential threat of the disease. Therefore, the development of a prediction model for mitigating the risk of early leaf spot in peanut production is important. The specific objective of this study was to demonstrate the application of the high-resolution Weather Research and Forecasting (WRF) model for management of early leaf spot in peanut. We coupled high-resolution weather output of the WRF, i.e. relative humidity and temperature, with the Oklahoma peanut leaf spot advisory model in predicting favorable conditions for early leaf spot infection over Georgia in 2007. Results showed a more favorable infection condition in the southeastern coastline of Georgia where the infection threshold were met sooner compared to the southwestern and central part of Georgia where the disease risk was lower. A newly introduced infection threat index indicates that the leaf spot threat threshold was met sooner at Alma, GA, compared to Tifton and Cordele, GA. The short-term prediction of weather parameters and their use in the management of peanut diseases is a viable and promising technique, which could help growers make accurate management decisions, and lower disease impact through optimum timing of fungicide applications.

  16. Major QTL Conferring Resistance to Rice Bacterial Leaf Streak

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bacterial leaf streak (BLS) is one of the important limiting factors to rice production in southern China and other tropical and sub-tropical areas in Asia. Resistance to BLS was found to be a quantitative trait and no major resistant gene was located in rice until date. In the present study, a new major quantitative trait locus (QTL) conferring resistance to BLS was identified from a highly resistant variety Dular by the employment of Dular/Balilla (DB) and Dular/IR24 (DI) segregation populations and was designated qBLSR-11-1. This QTL was located between the simple sequence repeat (SSR) markers RM120 and RM441 on chromosome 11 and could account for 18.1-21.7% and 36.3% of the variance in DB and DI populations, respectively. The genetic pattern of rice resistance to BLS was discussed.

  17. Weather based warning systems for bean angular-leaf-spot and anthracnose

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    2012-09-01

    Full Text Available Data available in the literature were used to develop a warning system for bean angular leaf spot and anthracnose, caused by Phaeoisariopsis griseola and Colletotrichum lindemuthianum, respectively. The model is based on favorable environmental conditions for the infectious process such as continuous leaf wetness duration and mean air temperature during this subphase of the pathogen-host relationship cycle. Equations published by DALLA PRIA (1977 showing the interactions of those two factors on the disease severity were used. Excell spreadsheet was used to calculate the leaf wetness period needed to cause different infection probabilities at different temperature ranges. These data were employed to elaborate critical period tables used to program a computerized electronic device that records leaf wetness duration and mean temperature and automatically shows the daily disease severity value (DDSV for each disease. The model should be validated in field experiments under natural infection for which the daily disease severity sum (DDSS should be identified as a criterion to indicate the beginning and the interval of fungicide applications to control both diseases.

  18. Bacterial leaf symbiosis in angiosperms: host specificity without co-speciation.

    Directory of Open Access Journals (Sweden)

    Benny Lemaire

    Full Text Available Bacterial leaf symbiosis is a unique and intimate interaction between bacteria and flowering plants, in which endosymbionts are organized in specialized leaf structures. Previously, bacterial leaf symbiosis has been described as a cyclic and obligate interaction in which the endosymbionts are vertically transmitted between plant generations and lack autonomous growth. Theoretically this allows for co-speciation between leaf nodulated plants and their endosymbionts. We sequenced the nodulated Burkholderia endosymbionts of 54 plant species from known leaf nodulated angiosperm genera, i.e. Ardisia, Pavetta, Psychotria and Sericanthe. Phylogenetic reconstruction of bacterial leaf symbionts and closely related free-living bacteria indicates the occurrence of multiple horizontal transfers of bacteria from the environment to leaf nodulated plant species. This rejects the hypothesis of a long co-speciation process between the bacterial endosymbionts and their host plants. Our results indicate a recent evolutionary process towards a stable and host specific interaction confirming the proposed maternal transmission mode of the endosymbionts through the seeds. Divergence estimates provide evidence for a relatively recent origin of bacterial leaf symbiosis, dating back to the Miocene (5-23 Mya. This geological epoch was characterized by cool and arid conditions, which may have triggered the origin of bacterial leaf symbiosis.

  19. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs.

  20. A review on threat of gray leaf spot disease of maize in Asia

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    Narayan Bahadur Dhami

    2015-12-01

    Full Text Available Biotic and biotic constraints are yield limiting factors in maize producing regions. Among these gray leaf spot is a yield limiting foliar disease of maize in high land regions of Asia. This review is done from related different national and international journals, thesis, books, research papers etc. The objectives of this review are to become familiar with genetics and inheritance, epidemiology, symptoms and disease management strategies etc. High relative humidity, temperature, minimum tillage and maize monoculture are important factors responsible for disease development. The sibling species of Cercospora zeae-maydis (Tehon and Daniels, 1925 Group I and Group II and Cercospora sorghai var. maydis (Chupp, 1954 are associated with this disease. Pathogens colonize in maize debris. Conidia are the source of inoculums for disease spread. Severe blighting of leaves reduces sugars, stalk lodging and causes premature death of plants resulting in yield losses of up to 100%. Disease management through cultural practices is provisional. The use of fungicides for emergencies is effective however; their prohibitive cost and detrimental effects on the environment are negative consequences. The inheritance of tolerance is quantitative with small additive effects. The introgression of resistant genes among the crosses of resistant germplasm enhances the resistance. The crosses of resistant and susceptible germplasm possess greater stability than the crosses of susceptible and resistant germplasm. The development of gray leaf spot tolerant populations through tolerance breeding principle is an economical and sustainable approach to manage the disease.

  1. The disease prevalence and severity of Cercospora leaf spot in sugar beet cultivations in Kayseri

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    Hacer Handan ALTINOK

    2012-12-01

    Full Text Available Cercospora leaf spot disease (Cercospora beticola Sacc., is one of the most economically important fungal diseases in sugar beet growing. Under appropriate climatic conditions, the disease can reach epidemic levels. Although some fungicides exist for disease control, resistance development by pathogen against fungicides is creating difficulties. Besides, use of resistant varieties which is considered as the most efficient and environment-friendly method is adversely affected by pathogen’s ability to exhibit high genetic variations and varying resistance levels against different races of pathogen restricts the success of resistance breeding studies. In order to reveal status of this disease in Kayseri province, surveys were conducted in 2010 and 2011 in sugar beet growing areas and disease prevalence and severity were determined. Approximately, 1500 da area in 90 fields were examined and about 700 da of this area found as infected with Cercospora leaf spot disease in both years of the survey. Highest disease prevalence and severity were found as 80 % and 45 %, respectively, in Sarıoğlan district, which is followed by central district, Develi and Bünyan. Among surveyed districts, lowest prevalence and severity were detected as approx. 65 % and 35 %, respectively, in Yeşilhisar.

  2. Transcriptome profiling of buffalograss challenged with the leaf spot pathogen Curvularia inaequalis

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    Bimal Sajeewa Amaradasa

    2016-05-01

    Full Text Available Buffalograss (Bouteloua dactyloides is a low maintenance United States native turfgrass species with exceptional drought, heat and cold tolerance. Leaf spot caused by Curvularia inaequalis negatively impacts buffalograss visual quality. Two leaf spot susceptible and two resistant buffalograss lines were challenged with C. inaequalis. Samples were collected from treated and untreated leaves when susceptible lines showed symptoms. Transcriptome sequencing was done and differentially expressed genes were identified. Approximately 27 million raw sequencing reads were produced per sample. More than 86% of the sequencing reads mapped to an existing buffalograss reference transcriptome. De novo assembly of unmapped reads was merged with the existing reference to produce a more complete transcriptome. There were 461 differentially expressed transcripts between the resistant and susceptible lines when challenged with the pathogen and 1552 in its absence. Previously characterized defense-related genes were identified among the differentially expressed transcripts. Twenty one resistant line transcripts were similar to genes regulating pattern triggered immunity and 20 transcripts were similar to genes regulating effector triggered immunity. There were also nine up-regulated transcripts in resistance lines which showed potential to initiate systemic acquired resistance (SAR and three transcripts encoding pathogenesis-related proteins which are downstream products of SAR. This is the first study characterizing changes in the buffalograss transcriptome when challenged with C. inaequalis.

  3. Severity of banana leaf spot in an intercropping system in two cycles of banana Prata Anã

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    Valdeir Dias Gonçalves

    2008-01-01

    Full Text Available Prata Anã is the most planted banana cultivar in northern Minas Gerais, Brazil. It is however susceptible toseveral pathogens. This study was carried out to evaluate the disease severity of banana leaf spot in the Prata Anã cv. in thefirst and second cycle under six different planting systems. The randomized block experimental design was used with sixtreatments and four replications. In an evaluation of the severity of banana leaf spot, no disease symptoms were found onThap Maeo and Caipira. The evolution curve of the disease indicated seasonal effects in the first and second cycles. Theseverity of banana leaf spot was highest soon after the regional rainy period from November to March. A comparison of themeans of the evaluations indicated a reduction in disease severity from the first to the second cycle.

  4. Optical Inspection and Morphological Analysis of Diospyros kaki Plant Leaves for the Detection of Circular Leaf Spot Disease

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    Ruchire Eranga Wijesinghe

    2016-08-01

    Full Text Available The feasibility of using the bio-photonic imaging technique to assess symptoms of circular leaf spot (CLS disease in Diospyros kaki (persimmon leaf samples was investigated. Leaf samples were selected from persimmon plantations and were categorized into three groups: healthy leaf samples, infected leaf samples, and healthy-looking leaf samples from infected trees. Visually non-identifiable reduction of the palisade parenchyma cell layer thickness is the main initial symptom, which occurs at the initial stage of the disease. Therefore, we established a non-destructive bio-photonic inspection method using a 1310 nm swept source optical coherence tomography (SS-OCT system. These results confirm that this method is able to identify morphological differences between healthy leaves from infected trees and leaves from healthy and infected trees. In addition, this method has the potential to generate significant cost savings and good control of CLS disease in persimmon fields.

  5. Optical Inspection and Morphological Analysis of Diospyros kaki Plant Leaves for the Detection of Circular Leaf Spot Disease.

    Science.gov (United States)

    Wijesinghe, Ruchire Eranga; Lee, Seung-Yeol; Kim, Pilun; Jung, Hee-Young; Jeon, Mansik; Kim, Jeehyun

    2016-08-12

    The feasibility of using the bio-photonic imaging technique to assess symptoms of circular leaf spot (CLS) disease in Diospyros kaki (persimmon) leaf samples was investigated. Leaf samples were selected from persimmon plantations and were categorized into three groups: healthy leaf samples, infected leaf samples, and healthy-looking leaf samples from infected trees. Visually non-identifiable reduction of the palisade parenchyma cell layer thickness is the main initial symptom, which occurs at the initial stage of the disease. Therefore, we established a non-destructive bio-photonic inspection method using a 1310 nm swept source optical coherence tomography (SS-OCT) system. These results confirm that this method is able to identify morphological differences between healthy leaves from infected trees and leaves from healthy and infected trees. In addition, this method has the potential to generate significant cost savings and good control of CLS disease in persimmon fields.

  6. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

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    Zebenay Gezahegn

    2015-02-01

    Full Text Available Objective: To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether leaf extracts of Thevetia peruviana (T. peruviana against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods: The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results: The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions: The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

  7. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Zebenay Gezahegn; Mohd Sayeed Akhtar; Delelegn Woyessa; Yinebeb Tariku

    2015-01-01

    Objective:To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether) leaf extracts of Thevetia peruviana (T. peruviana) against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods:The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results:The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions:The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

  8. Common bean breeding for resistance to anthracnose and angular leaf spot assisted by SCAR molecular markers

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    Gilmar Silvério da Rocha

    2012-01-01

    Full Text Available The objective of the present study was to assess the genetic potential of inbred carioca common bean families from five populations derived from crossings involving elite lines and a disease-resistant line (Rudá- R, and to assess the efficiency of SCAR molecular markers in selecting plants resistant to anthracnose and angular leaf spot, at the time of bulk formation. Plant architecture, yield and grain type were assessed. Significant effect among families within population was observed, suggesting wide genetic variability for the characters assessed. Twenty-six superior families were selected. The families contained the greatest number of markers, identified by SCAR molecular markers in the F4 generation. Eighteen of these families were resistant to the races 65 and 453 of Colletotrichum lindemuthianum and five were resistant to the race 63.23 of Pseudocercospora griseola. Thus selection assisted by SCAR markers, in the F4 generation, was an important tool in common bean br e eding.

  9. Bioefficacy of plant extracts to control Cercospora leaf spot of mungbean (Vigna radiata

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    M.N. Uddin

    2013-06-01

    Full Text Available The experiment was conducted at Bangladesh Agricultural Research Institute farm, Joydebpur, Gazipur during March to July 2007 to evaluate the bioefficacy of some plant extracts in controlling Cercospora leaf spot of mungbean. Six indigenous plant species i.e. Neem leaves extract (1:4 w/v, Garlic cloves extract (1:5 w/v, Biskatali leaves extract (1:4 w/v, Alamanda leaves extract (1:6 w/v, Arjun leaves extract (1:4 w/v and Debdaru leaves extract (1:5 w/v were used in this experiment. The experiment was laid out in RCBD with seven treatments and four replications. Data on disease incidence, severity, yield contributing characters and yield of mungbean were recorded. Naturally, infection of the disease was considered in this experiment. The lowest disease incidence (7.33% at 60 DAS was found in T1. Lowest and similar disease severity (PDI= 4.55 was found in T2 and T3 at the same DAS. Neem extract treated plots gave better response in yield (1.26 t ha-1 and all the yield contributing parameters like inflorescences plant-1 (13.45, tallest plant (51.44 cm, the maximum number of pods plant-1 (26.81, length of pod (8.56 cm, number of seeds pod-1 (12.64 and 1000 seeds weight (27.33 g followed by T2 and T3. The highest disease incidence (26.50% and disease index (13.65% were recorded in treatment T7 at 60 DAS. Yield and all yield contributing factors were lowest in same treatment. The results of the experiment suggested that the use of neem leaves extracts are effective for minimizing Cercospora leaf spot incidence, severity and increasing yield of mungbean.

  10. Re-evaluating the taxonomic status of Phaeoisariopsis griseola, the causal agent of angular leaf spot of bean

    NARCIS (Netherlands)

    Crous, Pedro W; Liebenberg, Merion M; Braun, Uwe; Groenewald, Johannes Z

    2006-01-01

    Angular leaf spot of Phaseolus vulgaris is a serious disease caused by Phaeoisariopsis griseola, in which two major gene pools occur, namely Andean and Middle-American. Sequence analysis of the SSU region of nrDNA revealed the genus Phaeoisariopsis to be indistinguishable from other hyphomycete anam

  11. Re-evaluating the taxonomic status of Phaeoisariopsis griseola, the causal agent of angular leaf spot of bean.

    NARCIS (Netherlands)

    Crous, P.W.; Liebenberg, M.M.; Braun, U.; Groenewald, J.Z.

    2006-01-01

    Angular leaf spot of Phaseolus vulgaris is a serious disease caused by Phaeoisariopsis griseola, in which two major gene pools occur, namely Andean and Middle-American. Sequence analysis of the SSU region of nrDNA revealed the genus Phaeoisariopsis to be indistinguishable from other hyphomycete anam

  12. Novel Pseudomonas syringae strains associated with leaf spot diseases on watermelon (Citrullus lanatus) and squash (Cucurbita pepo) in California

    Science.gov (United States)

    In 2006 and 2011, bacteria, fluorescent on KMB, were isolated from leaf spots of greenhouse-grown watermelon (Citrullus lanatus) and field-grown squash (Cucurbita pepo) in coastal California. Biochemical characterization of the isolates indicated that they belonged to Pseudomonas syringae. Multilocu...

  13. Systems genetics reveals a transcriptional network associated with susceptibility in the maize-grey leaf spot pathosystem

    Science.gov (United States)

    We have applied a systems genetics approach to elucidate molecular mechanisms of maize responses to gray leaf spot (GLS) disease, caused by Cercospora zeina, a major threat to maize production globally. We conducted expression QTL (eQTL) analysis of gene expression variation measured in earleaf samp...

  14. Xanthomonas euvesicatoria Causes Bacterial Spot Disease on Pepper Plant in Korea

    Science.gov (United States)

    Kyeon, Min-Seong; Son, Soo-Hyeong; Noh, Young-Hee; Kim, Yong-Eon; Lee, Hyok-In; Cha, Jae-Soon

    2016-01-01

    In 2004, bacterial spot-causing xanthomonads (BSX) were reclassified into 4 species—Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes—gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria. PMID:27721693

  15. Xanthomonas euvesicatoria Causes Bacterial Spot Disease on Pepper Plant in Korea

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    Min-Seong Kyeon

    2016-10-01

    Full Text Available In 2004, bacterial spot-causing xanthomonads (BSX were reclassified into 4 species—Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes—gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria.

  16. Role of leaf surface sugars in colonization of plants by bacterial epiphytes.

    Science.gov (United States)

    Mercier, J; Lindow, S E

    2000-01-01

    The relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of Pseudomonas fluorescens on individual bean leaves. Data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. Sugars were depleted during the course of bacterial colonization of the leaf surface. However, about 20% of readily utilizable sugar, such as glucose, present initially remained on fully colonized leaves. The amounts of sugars on a population of apparently identical individual bean leaves before and after microbial colonization exhibited a similar right-hand-skewed distribution and varied by about 25-fold from leaf to leaf. Total bacterial population sizes on inoculated leaves under conditions favorable for bacterial growth also varied by about 29-fold and exhibited a right-hand-skewed distribution. The amounts of sugars on leaves of different plant species were directly correlated with the maximum bacterial population sizes that could be attained on those species. The capacity of bacteria to deplete leaf surface sugars varied greatly among plant species. Plants capable of supporting high bacterial population sizes were proportionally more depleted of leaf surface nutrients than plants with low epiphytic populations. Even in species with a high epiphytic bacterial population, a substantial amount of sugar remained after bacterial colonization. It is hypothesized that residual sugars on colonized leaves may not be physically accessible to the bacteria due to limitations in wettability and/or diffusion of nutrients across the leaf surface.

  17. Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

    Science.gov (United States)

    Möller, Jens; Emge, Philippe; Avalos Vizcarra, Ima; Kollmannsberger, Philip; Vogel, Viola

    2013-12-01

    Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length.

  18. Salicylic acid confers enhanced resistance to Glomerella leaf spot in apple.

    Science.gov (United States)

    Zhang, Ying; Shi, Xiangpeng; Li, Baohua; Zhang, Qingming; Liang, Wenxing; Wang, Caixia

    2016-09-01

    Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emergent disease that results in severe defoliation and fruit spots in apple. Currently, there are no effective means to control this disease except for the traditional fungicide sprays. Induced resistance by elicitors against pathogens infection is a widely accepted eco-friendly strategy. In the present study, we investigated whether exogenous application of salicylic acid (SA) could improve resistance to GLS in a highly susceptible apple cultivar (Malus domestica Borkh. cv. 'Gala') and the underlying mechanisms. The results showed that pretreatment with SA, at 0.1-1.0 mM, induced strong resistance against GLS in 'Gala' apple leaves, with SA treated leaves showing significant reduction in lesion numbers and disease index. Concurrent with the enhanced disease resistance, SA treatment markedly increased the total antioxidant capacity (T-AOC) and defence-related enzyme activities, including catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). As expected, SA treatment also induced the expression levels of five pathogenesis-related (PR) genes including PR1, PR5, PR8, Chitinase and β-1,3-glucanase. Furthermore, the most pronounced and/or rapid increase was observed in leaves treated with SA and subsequently inoculated with G. cingulata compared to the treatment with SA or inoculation with the pathogen. Together, these results suggest that exogenous SA triggered increase in reactive oxygen species levels and the antioxidant system might be responsible for enhanced resistance against G. cingulata in 'Gala' apple leaves.

  19. In Vivo Monitoring on Growth and Spread of Gray Leaf Spot Disease in Capsicum annuum Leaf Using Spectral Domain Optical Coherence Tomography

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    Naresh Kumar Ravichandran

    2016-01-01

    Full Text Available We have demonstrated the application of optical coherence tomography (OCT in diagnosis of growth and spread of the gray leaf spot disease in Capsicum annuum leaf caused by the fungus Stemphylium lycopersici. Using 2D cross-sectional and 3D volumetric images of OCT, in vivo study of layer differences between fungus infected leaves and healthy leaves was observed with distinctive features. We observed that the internal layers of the disease-affected parts of the leaf seem to merge forming a single thick layer. The obtained OCT results verify the noninvasive diagnosis ability of fungal growth and spread in Capsicum annuum leaves and the applicability of this methodology for other plant diseases.

  20. Hyperspectral Imaging for Determining Pigment Contents in Cucumber Leaves in Response to Angular Leaf Spot Disease.

    Science.gov (United States)

    Zhao, Yan-Ru; Li, Xiaoli; Yu, Ke-Qiang; Cheng, Fan; He, Yong

    2016-06-10

    Hyperspectral imaging technique was employed to determine spatial distributions of chlorophyll (Chl), and carotenoid (Car) contents in cucumber leaves in response to angular leaf spot (ALS). Altogether, 196 hyperspectral images of cucumber leaves with five infection severities of ALS were captured by a hyperspectral imaging system in the range of 380-1,030 nm covering 512 wavebands. Mean spectrum were extracted from regions of interest (ROIs) in the hyperspectral images. Partial least square regression (PLSR) models were used to develop quantitative analysis between the spectra and the pigment contents measured by biochemical analyses. In addition, regression coefficients (RCs) in PLSR models were employed to select important wavelengths (IWs) for modelling. It was found that the PLSR models developed by the IWs provided the optimal measurement results with correlation coefficient (R) of prediction of 0.871 and 0.876 for Chl and Car contents, respectively. Finally, Chl and Car distributions in cucumber leaves with the ALS infection were mapped by applying the optimal models pixel-wise to the hyperspectral images. The results proved the feasibility of hyperspectral imaging for visualizing the pigment distributions in cucumber leaves in response to ALS.

  1. Grouping sunflower genotypes for yield, oil content, and reaction to Alternaria leaf spot using GGE biplot

    Directory of Open Access Journals (Sweden)

    Regina Maria Villas Bôas de Campos Leite

    2015-08-01

    Full Text Available Abstract:The objective of this work was to evaluate the suitability of the multivariate method of principal component analysis (PCA using the GGE biplot software for grouping sunflower genotypes for their reaction to Alternaria leaf spot disease (Alternariaster helianthi, and for their yield and oil content. Sixty-nine genotypes were evaluated for disease severity in the field, at the R3 growth stage, in seven growing seasons, in Londrina, in the state of Paraná, Brazil, using a diagrammatic scale developed for this disease. Yield and oil content were also evaluated. Data were standardized using the software Statistica, and GGE biplot was used for PCA and graphical display of data. The first two principal components explained 77.9% of the total variation. According to the polygonal biplot using the first two principal components and three response variables, the genotypes were divided into seven sectors. Genotypes located on sectors 1 and 2 showed high yield and high oil content, respectively, and those located on sector 7 showed tolerance to the disease and high yield, despite the high disease severity. The principal component analysis using GGE biplot is an efficient method for grouping sunflower genotypes based on the studied variables.

  2. Using SPOT data and leaf area index for rice yield estimation in Egyptian Nile delta

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    M. Aboelghar

    2011-12-01

    Full Text Available The objective of the current work is to generate statistical empirical rice yield estimation models under the local conditions of the Egyptian Nile delta. The methodology is based on regressing measured yield with satellite derived spectral information or leaf area index (LAI. LAI field measurements and spectral information from SPOT data collected during two crop seasons are examined against measured yield to generate the yield models. Near-infrared and red bands, six vegetation indices and LAI of 100 points are used as the main inputs for the modeling process while 20 points of the same are used for validation process. Nine models are generated and tested against the observed yield. Comparing the generated models show relatively higher superiority of (LAI-yield and (infrared-yield models over the rest of the models with (0.061 and (0.090 as a standard error of estimate and (0.945 and (0.883 as coefficient of determinations between modeled and observed yield. The models are applicable a month before harvest for similar regions with same conditions.

  3. Molecular characterization of RAPD and SCAR marker linked to the frog-eye leaf spot resistance gene in soybean

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two fragments SCS3620 and SCS3580 of the co-dominant marker OPS03620&580 that were linked to the resistance gene of soybean frog-eye leaf spot have been completely sequenced.A significant insertion of 30 bp is the main reason of the polymorphism between the two fragments.The results of Southern hybridization indicate that SCS3620 derives from a single- or low-copy sequence and can be used as an RFLP probe.A co-dominant SCAR marker SCS3620&580 has been developed based on the sequences.The segregation of SCS3620&580 is similar to that of RAPD marker OPS03620&580.Significant polymorphism has been shown between resistant and susceptible genotypes when 62 soybean genotypes were surveyed for the SCAR marker.Therefore,the marker can be used in the resistance breeding of soybean frog-eye leaf spot by marker-assisted selection.

  4. Evaluation of the Efficacy of Different Fungicide for the Management of Alternaria Leaf Spot Disease of Chilli

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Yadav

    2015-03-01

    Full Text Available Alternaria leaf spot of chilli caused by Alternaria alternate is an important disease affecting chilly production areas in India. The disease is primarily controlled through the use of fungicidal seed treatments. In this study, different fungicides viz. Captol, Captan, Ziram, Captofol, Thiram, Indofill Z 78 and Indofill Z 45 were assessed for their ability to reduce the growth of Alternaria alternata under laboratory conditions. Maximum inhibition (100% was achieved by Captol and capton followed by captofol (89.5 % while 0.1 % dose given. This paper reports the efficacy of fungicides that can be used under field conditions to control alternaria leaf spot in tropical regions and demonstrates the use of a method of application that could significantly improve the efficacy of disease control.

  5. Antibacterial activity of essential oils on Xanthomonas vesicatoria and control of bacterial spot in tomato

    Directory of Open Access Journals (Sweden)

    Gilvaine Ciavareli Lucas

    2012-03-01

    Full Text Available The objective of this work was to evaluate the effects of plant essential oils (EOs on the growth of Xanthomonas vesicatoria, on bacterial morphology and ultrastructure, and on the severity of tomato bacterial spot. EOs from citronella, clove, cinnamon, lemongrass, eucalyptus, thyme, and tea tree were evaluated in vitro at concentrations of 0.1, 1.0, 10, and 100% in 1.0% powdered milk. The effect of EOs, at 0.1%, on the severity of tomato bacterial spot was evaluated in tomato seedlings under greenhouse conditions. The effects of citronella, lemongrass, clove, and tea tree EOs, at 0.1%, on X. vesicatoria cells were evaluated by transmission electron microscopy. All EOs showed direct toxic effect on the bacteria at a 10%-concentration in vitro. Under greenhouse conditions, the EOs of clove, citronella, tea tree, and lemongrass reduced disease severity. EOs of clove and tea tree, and streptomycin sulfate promoted loss of electron-dense material and alterations in the cytoplasm, whereas EO of tea tree promoted cytoplasm vacuolation, and those of citronella, lemongrass, clove, and tea tree caused damage to the bacterial cell wall. The EOs at a concentration of 0.1% reduce the severity of the disease.

  6. Dose and application rate of fungicide to control leaf rust (Puccinia triticina and yellow spot (Pyrenophora tritici repentis of wheat

    Directory of Open Access Journals (Sweden)

    Gustavo Migliorini de Oliveira

    2015-02-01

    Full Text Available The aim of this paper was to study the role of dose and rate of application, and the effect of concentration of fungicide in the spray solution resulted from the interaction of these factors, in the control of leaf rust and yellow spot of wheat. It was conducted two experiments, the first used the CD 104 cultivar (susceptible to lead rust and yellow spot. The experimental design was an factorial 3 x 3 + untreated control, that involve the factors dose (0,25, 0,30 and 0,35 L.ha-1 and application rate (143, 286 and 429 L.ha-1. The second experiment used the BRS 208 cultivar (resistant to leaf rust and moderately resistant to yellow spot. The experimental design was an factorial 2 x 2 + untreated control, consisting the factors dose (0,2 and 0,3 L.ha-1 and application rate (143 and 286 L.ha-1. The applications were made with a coastal sprayer by CO2, pressure of 250 kPa, XR 110-02 nozzle, which generated an application rate of 143 L.ha-1. The respective rates of each treatment were changed by the number of sprayers per area. It was also used a spore trap denominated Siga, associated with meteorological data and weather forecast, which detected spores of rust and yellow spot before the symptoms in the plants, helping in the identification of disease and in the timing of application. There wasn´t any interaction between dose and rate of application for any of the experiments, therefore, there wasn´t effect of concentration of fungicide in control. The dose and rate of application just influenced in the control of the yellow spot. Higher doses and rates were more effective. However, no difference was observed for yield and hectolitre weight among treatments, except untreated control

  7. Fenton reagent and titanium dioxide nanoparticles as antifungal agents to control leaf spot of sugar beet under field conditions

    Directory of Open Access Journals (Sweden)

    Hamza Amany

    2016-07-01

    Full Text Available In this study, foliar sprays of Fenton solutions (Fenton reaction, Fenton-like reaction and Fenton complex, titanium dioxide (TiO2 and the recommended fungicide (chlorothalonil were estimated in the control of sugar beet leaf spot caused by Cercospora beticola under field conditions in two growing seasons. In addition, the impacts of these treatments on some crop characters (leaf dry weight, root fresh weight, soluble solid content, sucrose content and purity of sugar were examined. Biochemical and histological changes in the livers and kidneys of treated rats compared to an untreated control were utilized to assess the toxicity of the examined curative agents. Overall, chlorothalonil and Fenton complex were the most effective treatments for disease suppression in both tested seasons followed by Fenton-like reagent, Fenton’s reagent and TiO2, respectively. Growth and yield characters of treated sugar beet significantly increased in comparison to an untreated control. There were mild or no (biochemical and histological changes in the livers and kidneys of treated rats compared to the control. Fenton solutions and TiO2 may offer a new alternative for leaf spot control in sugar beet.

  8. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

    Institute of Scientific and Technical Information of China (English)

    Rabia Naz; Asghari Bano

    2012-01-01

    Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  9. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains.

    Science.gov (United States)

    Naz, Rabia; Bano, Asghari

    2012-12-01

    To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  10. Effect of leaf type and pesticide exposure on abundance of bacterial taxa in mosquito larval habitats.

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    Ephantus J Muturi

    Full Text Available Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations of four pesticides with different modes of action on the target organisms; permethrin, malathion, atrazine and glyphosate. We tested the hypotheses that leaf species support different quantities of major taxonomic groups of bacteria and that exposure to pesticides at environmentally relevant concentrations alters bacterial abundance and community structure in mosquito larval habitats. We found support for both hypotheses suggesting that leaf litter identity and chemical contamination may alter the quality and quantity of mosquito food base (microbial communities in larval habitats. The effect of pesticides on microbial communities varied significantly among leaf types, suggesting that the impact of pesticides on natural microbial communities may be highly complex and difficult to predict. Collectively, these findings demonstrate the potential for detritus composition within mosquito larval habitats and exposure to pesticides to influence the quality of mosquito larval habitats.

  11. Mapping of angular leaf spot resistance QTL in common bean (Phaseolus vulgaris L. under different environments

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    Oblessuc Paula

    2012-06-01

    Full Text Available Abstract Background Common bean (Phaseolus vulgaris L. is the most important grain legume for human diet worldwide and the angular leaf spot (ALS is one of the most devastating diseases of this crop, leading to yield losses as high as 80%. In an attempt to breed resistant cultivars, it is important to first understand the inheritance mode of resistance and to develop tools that could be used in assisted breeding. Therefore, the aim of this study was to identify quantitative trait loci (QTL controlling resistance to ALS under natural infection conditions in the field and under inoculated conditions in the greenhouse. Results QTL analyses were made using phenotypic data from 346 recombinant inbreed lines from the IAC-UNA x CAL 143 cross, gathered in three experiments, two of which were conducted in the field in different seasons and one in the greenhouse. Joint composite interval mapping analysis of QTL x environment interaction was performed. In all, seven QTLs were mapped on five linkage groups. Most of them, with the exception of two, were significant in all experiments. Among these, ALS10.1DG,UC presented major effects (R2 between 16% - 22%. This QTL was found linked to the GATS11b marker of linkage group B10, which was consistently amplified across a set of common bean lines and was associated with the resistance. Four new QTLs were identified. Between them the ALS5.2 showed an important effect (9.4% under inoculated conditions in the greenhouse. ALS4.2 was another major QTL, under natural infection in the field, explaining 10.8% of the variability for resistance reaction. The other QTLs showed minor effects on resistance. Conclusions The results indicated a quantitative inheritance pattern of ALS resistance in the common bean line CAL 143. QTL x environment interactions were observed. Moreover, the major QTL identified on linkage group B10 could be important for bean breeding, as it was stable in all the environments. Thereby, the GATS11b

  12. Bacterial spot and early blight biocontrol by epiphytic bacteria in tomato plants

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    Roberto Lanna Filho

    2010-12-01

    Full Text Available The objective of this work was to evaluate in vitro and in vivo biocontrol of bacterial spot (Xanthomonas vesicatoria and early blight (Alternaria solani by the epiphytic bacteria Paenibacillus macerans and Bacillus pumilus. Tomato plants were previously sprayed with epiphytic bacteria, benzalkonium chloride and PBS buffer and, after four days, they were inoculated with A. solani and X. vesicatoria. To determine the phytopathogenic bacteria population, leaflet samples were collected from each treatment every 24 hours, for seven days, and plated on semi-selective medium. The effect of epiphytic bacteria over phytopathogens was performed by the antibiosis test and antagonistic activity measured by inhibition zone diameter. The epiphytic and benzalkonium chloride drastically reduced the severity of early blight and bacterial spot in comparison to the control (PBS. In detached leaflets, the epiphytic bacteria reduced in 70% the number of phytopathogenic bacteria cells in the phylloplane. The antibiosis test showed that the epiphytic bacteria efficiently inhibit the phytopathogens growth. In all the bioassays, the epiphytic bacteria protect tomato plants against the phytopathogens

  13. ldentification and Control Methods of Eggplant Black Blight, Ascochyta Leaf Spot, Early Blight, Brown Leaf Spot, Anthracnose, Black Spot and Rhizopus Fruit Rot%茄子黑枯病、褐轮纹病、早疫病、褐斑病、炭疽病、黑斑病和黑根霉果腐病的识别与防治

    Institute of Scientific and Technical Information of China (English)

    张杨林; 郑丹丹

    2013-01-01

    The symptom and disease characteristics of eggplant black blight, ascochyta leaf spot, early blight, brown leaf spot, anthracnose, black spot and rhizopus fruit rot were introduced. Then the integrated control methods were put forward, which contained measures of a-gricultural control, chemical control and so on.%介绍了茄子黑枯病、褐轮纹病、早疫病、褐斑病、炭疽病、黑斑病和黑根霉果腐病的危害症状、发病特点,并从农业措施、化学防治等方面总结了各病害的综合防治方法。

  14. Salicylic acid and cysteine contribute to arbutin-induced alleviation of angular leaf spot disease development in cucumber.

    Science.gov (United States)

    Kuźniak, Elżbieta; Wielanek, Marzena; Chwatko, Grażyna; Głowacki, Rafał; Libik-Konieczny, Marta; Piątek, Milena; Gajewska, Ewa; Skłodowska, Maria

    2015-06-01

    Arbutin induced suppression of angular leaf spot disease in cucumber resulting from lower populations of Pseudomonas syringae pv lachrymans in the infected tissues. This study provides insight into mechanisms that may potentially account for this effect. In the absence of the pathogen, exogenous arbutin-induced expression of PR1, the marker of salicylic acid signaling, increased the content of salicylic acid and modulated the cysteine pool. This suggested that arbutin promoted cucumber plants to a "primed" state. When challenged with the pathogen, the arbutin-treated plants showed strongly reduced infection symptoms 7 days after inoculation. At this time point, they were characterized by higher contents of free and protein-bound cysteine due to higher cysteine biosynthetic capacity related to increased activities of serine acetyltransferase and cysteine synthase when compared with plants infected without arbutin treatment. Moreover, in the arbutin-treated and infected plants the contents of free salicylic acid and its conjugates were also increased, partly owing to its biosynthesis via the phenylpropanoid pathway. We suggest that arbutin-induced abrogation of angular leaf spot disease in cucumber could be mediated by salicylic acid and cysteine-based signaling.

  15. [Colonization characteristics of endophytic bacteria NJ13 in Panax ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng].

    Science.gov (United States)

    Chen, Chang-Qing; Li, Tong; Li, Xin-Lian; Jiang, Yun; Tian, Lei; Xu, Peng

    2014-05-01

    To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG.

  16. Bacterial Leaf Scorch of Amenity Trees a Wide-Spread Problem of Economic Significance to the Urban Forest

    Science.gov (United States)

    James Lashomb; Alan Iskra; Ann Brooks Gould; George Hamilton

    2003-01-01

    Bacterial leaf scorch (BLS) of amenity trees is caused by the bacterium Xylella fastidiosa, a xylem-limited pathogen that causes water stress resulting in leaf scorch, decline, and eventual death of affected trees. Recent surveys indicate that BLS is widespread throughout the eastern half of the United States. In New Jersey, BLS primarily affects red and pin oaks...

  17. The mechanics of bacterial cluster formation on plant leaf surfaces as revealed by bioreporter technology.

    Science.gov (United States)

    Tecon, Robin; Leveau, Johan H J

    2012-05-01

    Bacteria that colonize the leaves of terrestrial plants often occur in clusters whose size varies from a few to thousands of cells. For the formation of such bacterial clusters, two non-mutually exclusive but very different mechanisms may be proposed: aggregation of multiple cells or clonal reproduction of a single cell. Here we assessed the contribution of both mechanisms on the leaves of bean plants that were colonized by the bacterium Pantoea agglomerans. In one approach, we used a mixture of green and red fluorescent P. agglomerans cells to populate bean leaves. We observed that this resulted in clusters made up of only one colour as well as two-colour clusters, thus providing evidence for both mechanisms. Another P. agglomerans bioreporter, designed to quantify the reproductive success of bacterial colonizers by proxy to the rate at which green fluorescent protein is diluted from dividing cells, revealed that during the first hours on the leaf surface, many bacteria were dividing, but not staying together and forming clusters, which is suggestive of bacterial relocation. Together, these findings support a dynamic model of leaf surface colonization, where both aggregative and reproductive mechanisms take place. The bioreporter-based approach we employed here should be broadly applicable towards a more quantitative and mechanistic understanding of bacterial colonization of surfaces in general. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. First report of Elsinoe leaf and fruit spot and Elsinoe pyri on apple in Denmark

    DEFF Research Database (Denmark)

    Glazowska, Sylwia Emilia; Schiller, Michaela; Lund, Ole Søgaard

    2013-01-01

    An apple disease, known as “Topaz spot” in northern Europe (Trapman and Jansonius, 2008) has since year 2000 become widespread in Danish organic apple orchards (Malus domestica). Characteristic symptoms are small spots (black on fruits, brown on leaves) having a silvery-grey cen- tre. The associa...

  19. Effect of foliar fertilizer and fungicidal protection against leaf spot diseases on winter wheat

    Directory of Open Access Journals (Sweden)

    Agnieszka Mączyńska

    2012-12-01

    Full Text Available Field experiments were carried out in the seasons 2000/2001 and 2001/2002 in Plant Protection Institute, Sooenicowice Branch to assess the influence of foliar fertilizers such as Ekolist PK 1, Ekolist Mg, Mikrosol Z and Urea on healthiness of winter wheat. Foliar fertilizers were mixed with fungicides. The fungicides were applied at full or half recommended doses. The effect of the disease on wheat leaves was evaluated three times in each vegetation season. Remaining green leaf area (GLA of leaves was also determined. GLA of the leaves F-1 was not significantly different for each combination with different fertilization and different levels of chemical treatment. The application of foliar fertilizer only had no effect on green leaf area (GLA. The results indicate that foliar fertilization of all experimental plots improved leaf condition and therefore halted the development of wheat leaf diseases. The increases of 1000 grain mass and yield was high for each plot where a fertilizer and a full or half dose of a fungicide was applied. Foliar fertilizing with no chemical control had no proven effect on studied parameters.

  20. Protective Activity of the Mixtures of Pine Oil and Copper Hydroxide against Bacterial Spot and Anthracnose on Red Pepper

    Directory of Open Access Journals (Sweden)

    Jae-Woo Soh

    2014-09-01

    Full Text Available This research was performed to examine the protective activities of the mixtures of pine oil and copper hydroxide against bacterial spot and anthracnose on pepper plants. As for bacterial spot, the treatment of pine oil alone displayed high disease incidence (59.6% and low protective effect (28.9%. In comparison, the treatments of mixtures and copper hydroxide alone showed protective activities of 66.8-76.1%. The mixture of pine oil and copper hydroxide (4:1 suppressed the most effectively bacterial spot on pepper. On the other hand, the mixture of pine oil and copper hydroxide (4:1 also showed the strongest protective effect against pepper anthracnose among the 4 treatments tested; its disease incidence and disease control value were 49.8% and 41.7%, respectively. The other treatments showed low protective activities with control values of 7.4-17.1%. These results suggested that the mixture of pine oil and copper hydroxide (4:1 can be used for the environmental-friendly disease control of bacterial spot and anthracnose on pepper.

  1. Influence of leaf pubescence on the behavior of the two-spotted spider mite (Tetranychus urticae and the European red mite (Panonychus ulmi

    Directory of Open Access Journals (Sweden)

    Wojciech Warabieda

    2013-12-01

    Full Text Available Movement behavior of two mite species: two-spotted spider mite (Tetranychus urticae and European red mite (Panonychus ulmi on leaves of some apple cultivars (´Greensleeves´, ´Spartan' and SA 455-2 selection with different density of pubescence was analysed. Assessment of the leaf pubescence density was performed using an originally developed quick method based on digital pubescence mage analysis. For P.ulmi, both stop time and average speed did not depend on kind of leaf. In contrary. T.urticae revealed higher movement activity on slight pubescent leaves compared to leaves with high leaf hair density.

  2. Draft genome sequence of Cercospora sojina isolate S9, a fungus causing frogeye leaf spot (FLS disease of soybean

    Directory of Open Access Journals (Sweden)

    Fanchang Zeng

    2017-06-01

    Full Text Available Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. The fungus Cercospora sojina is a plant pathogen that threatens global soybean supplies. Here, we report the genome sequence of C. sojina strain S9 and detect genome features and predicted genomic elements. The genome sequence of C. sojina is a valuable resource with potential in studying the fungal pathogenicity and soybean host resistance to frogeye leaf spot (FLS, which is caused by C. sojina. The C. sojina genome sequence has been deposited and available at DDBJ/EMBL/GenBank under the project accession number AHPQ00000000.

  3. Fine-mapping of a major QTL controlling angular leaf spot resistance in common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Keller, Beat; Manzanares, Chloe; Jara, Carlos; Lobaton, Juan David; Studer, Bruno; Raatz, Bodo

    2015-05-01

    A major QTL for angular leaf spot resistance in the common bean accession G5686 was fine-mapped to a region containing 36 candidate genes. Markers have been developed for marker-assisted selection. Common bean (Phaseolus vulgaris L.) is an important grain legume and an essential protein source for human nutrition in developing countries. Angular leaf spot (ALS) caused by the pathogen Pseudocercospora griseola (Sacc.) Crous and U. Braun is responsible for severe yield losses of up to 80%. Breeding for resistant cultivars is the most ecological and economical means to control ALS and is particularly important for yield stability in low-input agriculture. Here, we report on a fine-mapping approach of a major quantitative trait locus (QTL) ALS4.1(GS, UC) for ALS resistance in a mapping population derived from the resistant genotype G5686 and the susceptible cultivar Sprite. 180 F3 individuals of the mapping population were evaluated for ALS resistance and genotyped with 22 markers distributed over 11 genome regions colocating with previously reported QTL for ALS resistance. Multiple QTL analysis identified three QTL regions, including one major QTL on chromosome Pv04 at 43.7 Mbp explaining over 75% of the observed variation for ALS resistance. Additional evaluation of 153 F4, 89 BC1F2 and 139 F4/F5/BC1F3 descendants with markers in the region of the major QTL delimited the region to 418 kbp harboring 36 candidate genes. Among these, 11 serine/threonine protein kinases arranged in a repetitive array constitute promising candidate genes for controlling ALS resistance. Single nucleotide polymorphism markers cosegregating with the major QTL for ALS resistance have been developed and constitute the basis for marker-assisted introgression of ALS resistance into advanced breeding germplasm of common bean.

  4. Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Perseguini, Juliana Morini Küpper Cardoso; Oblessuc, Paula Rodrigues; Rosa, João Ricardo Bachega Feijó; Gomes, Kleber Alves; Chiorato, Alisson Fernando; Carbonell, Sérgio Augusto Morais; Garcia, Antonio Augusto Franco; Vianello, Rosana Pereira; Benchimol-Reis, Luciana Lasry

    2016-01-01

    The common bean (Phaseolus vulgaris L.) is the world's most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum) and angular leaf spot (ALS; Pseudocercospora griseola) are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL) controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will contribute to more

  5. Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L..

    Directory of Open Access Journals (Sweden)

    Juliana Morini Küpper Cardoso Perseguini

    Full Text Available The common bean (Phaseolus vulgaris L. is the world's most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum and angular leaf spot (ALS; Pseudocercospora griseola are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will

  6. TALE-induced bHLH transcription factors that activate a pectate lyase contribute to water soaking in bacterial spot of tomato

    Science.gov (United States)

    Schwartz, Allison R.; Morbitzer, Robert; Lahaye, Thomas; Staskawicz, Brian J.

    2017-01-01

    AvrHah1 [avirulence (avr) gene homologous to avrBs3 and hax2, no. 1] is a transcription activator-like (TAL) effector (TALE) in Xanthomonas gardneri that induces water-soaked disease lesions on fruits and leaves during bacterial spot of tomato. We observe that water from outside the leaf is drawn into the apoplast in X. gardneri-infected, but not X. gardneriΔavrHah1 (XgΔavrHah1)-infected, plants, conferring a dark, water-soaked appearance. The pull of water can facilitate entry of additional bacterial cells into the apoplast. Comparing the transcriptomes of tomato infected with X. gardneri vs. XgΔavrHah1 revealed the differential up-regulation of two basic helix–loop–helix (bHLH) transcription factors with predicted effector binding elements (EBEs) for AvrHah1. We mined our RNA-sequencing data for differentially up-regulated genes that could be direct targets of the bHLH transcription factors and therefore indirect targets of AvrHah1. We show that two pectin modification genes, a pectate lyase and pectinesterase, are targets of both bHLH transcription factors. Designer TALEs (dTALEs) for the bHLH transcription factors and the pectate lyase, but not for the pectinesterase, complement water soaking when delivered by XgΔavrHah1. By perturbing transcriptional networks and/or modifying the plant cell wall, AvrHah1 may promote water uptake to enhance tissue damage and eventual bacterial egression from the apoplast to the leaf surface. Understanding how disease symptoms develop may be a useful tool for improving the tolerance of crops from damaging disease lesions. PMID:28100489

  7. Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis)

    Science.gov (United States)

    In previous work, using near isogenic line (NIL) populations in which segments of the tesosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot resistance. We identified...

  8. Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

    Science.gov (United States)

    The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

  9. Linkage mapping of the Phg-1 and Co-14 genes for resistance to angular leaf spot and anthracnose in the common bean cultivar AND 277

    Science.gov (United States)

    The Andean common bean (Phaseolus vulgaris L.) cultivar AND 277 is an important source of disease resistance to angular leaf spot (ALS, caused by Pseudocercospora griseola) and anthracnose (caused by Colletotrichum lindemuthianum). AND 277 has the Phg-1 gene that confers resistance to eight races of...

  10. Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Oliver Richard P

    2008-03-01

    Full Text Available Abstract Background Knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. In this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by Phoma medicaginis, an economically important necrotrophic pathogen of Medicago spp., was examined in the model legume M. truncatula. Results Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 × A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P Phoma medicaginis one (rnpm1 genetically mapped to the top arm of linkage group 4 (LG4. rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1–5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P rnpm2, was located on the lower arm of LG8 in the SA27063 × SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs are apparent in the genomic sequence of the reference accession A17 at the

  11. Hybrid Rice Resistant to Bacterial Leaf Blight Developed By Marker Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    CAO; Li-yong; ZHUANG; Jie-yun; YUAN; Shou-jiang; ZHAN; Xiao-deng; ZHENG; Kang-le; CHENG; Shi-hua

    2003-01-01

    Through recurrént backcrossing in combination with molecular marker-assisted selection (MAS), restorer lines R8006 and R1176 carrying Xa-21 , a gene having broad-spectrum resistance to rice bacterial leaf blight, were selected. By crossing the two lines to CMS line Zhong 9A, two new hybrid rice combinations, Zhongyou 6 and Zhongyou 1176 were developed. The hybrids showed high resistance to diseases, good grain quality and high yielding potential in national and provincial adaptability and yield trials.

  12. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria.

    Science.gov (United States)

    Yasmin, Sumera; Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1-19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82-116 μg mL-1) and produced indole acetic acid (0.48-1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice.

  13. Phenotypic and genotypic variation among Capsicum annuum recombinant inbred lines resistant to bacterial spot.

    Science.gov (United States)

    Moreira, S O; Rodrigues, R; Oliveira, H S; Medeiros, A M; Sudré, C P; Gonçalves, L S A

    2013-04-17

    A breeding program carried out under Brazilian growing conditions to obtain Capsicum annuum cultivars with disease resistance to bacterial spot (BS) produced 8 promising recombinant inbred lines (RILs). The present study aimed to characterize these RILs using phenotypic descriptors and molecular markers (inter-simple sequence repeat) and to confirm their resistance to BS. Twenty-two phenotypic descriptors and 15 inter-simple sequence repeat primers were used to characterize the RILs. The parent, UENF 1381, which is resistant to BS, and 'Casca Dura Ikeda', a traditional cultivar, were used as standards. Variability among genotypes was observed considering either binary or multicategorical characteristics, such as fruit length, fruit diameter, and fruit longitudinal and transversal section. Such variability in fruit traits can be exploited to develop new genotypes with BS resistance for various types of market consumption. RILs numbered 1, 3, and 6 were the most homogenous, whereas those coded 2, 5, 8, and 11 had the same level of heterogeneity as that observed in 'Casca Dura Ikeda'. Molecular analysis clustered the genotypes into 5 groups, with RILs 1, 2, 3, and 5 allocated in isolated groups. RILs 1, 2, 6, and 8 confirmed resistance to BS. Considering homogeneity level and BS resistance, RILs 1 and 6 were suitable for use as pre-cultivars in final tests to register and release two new C. annuum cultivars.

  14. Transgenic resistance confers effective field level control of bacterial spot disease in tomato.

    Directory of Open Access Journals (Sweden)

    Diana M Horvath

    Full Text Available We investigated whether lines of transgenic tomato (Solanum lycopersicum expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides.

  15. Identiifcation and Genetic Analysis of a Novel Rice Spotted-Leaf Mutant with Broad-Spectrum Resistance to Xanthomonas oryzae pv. oryzae

    Institute of Scientific and Technical Information of China (English)

    SHEN Hai-chao; SHI Yong-feng; FENG Bao-hua; WANG Hui-mei; XU Xia; HUANG Qi-na; LÜ Xiang-guang; WU Jian-li

    2014-01-01

    A spotted-leaf mutant of rice HM143 was isolated from an EMS-induced IR64 mutant bank. Brown lesions randomly distributed on leaf blades were observed about 3 wk after sowing. The symptom lasted for the whole plant growth duration. Histochemical analysis indicated that cell death occurred in and around the site of necrotic lesions accompanied with accumulation of hydrogen hyperoxide. Agronomic traits were largely similar to the wild type IR64 except seed setting rate and 1 000-grain weight which were signiifcantly decreased in the mutant. Disease resistance of the mutant to multiple races of Xanthomonas oryzae pv. oryzae was signiifcantly enhanced. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively termed splHM143. In addition, using molecular markers and 1 023 mutant type individuals from an F2 segregating population derived from the cross HM143/R9308, the spotted-leaf gene was ifnally delimited to an interval of 149 kb between markers XX25 and ID40 on the long arm of chromosome 4. splHM143 is likely a novel rice spotted-leaf gene since no other similar genes have been identiifed near the chromosomal region.

  16. Transcriptome Analysis of Poplar during Leaf Spot Infection with Sphaerulina spp.

    Science.gov (United States)

    Foster, Adam J; Pelletier, Gervais; Tanguay, Philippe; Séguin, Armand

    2015-01-01

    Diseases of poplar caused by the native fungal pathogen Sphaerulina musiva and related species are of growing concern, particularly with the increasing interest in intensive poplar plantations to meet growing energy demands. Sphaerulina musiva is able to cause infection on leaves, resulting in defoliation and canker formation on stems. To gain a greater understanding of the different responses of poplar species to infection caused by the naturally co-evolved Sphaerulina species, RNA-seq was conducted on leaves of Populus deltoides, P. balsamifera and P. tremuloides infected with S. musiva, S. populicola and a new undescribed species, Ston1, respectively. The experiment was designed to contain the pathogen in a laboratory environment, while replicating disease development in commercial plantations. Following inoculation, trees were monitored for disease symptoms, pathogen growth and host responses. Genes involved in phenylpropanoid, terpenoid and flavonoid biosynthesis were generally upregulated in P. balsamifera and P. tremuloides, while cell wall modification appears to play an important role in the defense of P. deltoides. Poplar defensive genes were expressed early in P. balsamifera and P. tremuloides, but their expression was delayed in P. deltoides, which correlated with the rate of disease symptoms development. Also, severe infection in P. balsamifera led to leaf abscission. This data gives an insight into the large differences in timing and expression of genes between poplar species being attacked by their associated Sphaerulina pathogen.

  17. Transcriptome Analysis of Poplar during Leaf Spot Infection with Sphaerulina spp.

    Directory of Open Access Journals (Sweden)

    Adam J Foster

    Full Text Available Diseases of poplar caused by the native fungal pathogen Sphaerulina musiva and related species are of growing concern, particularly with the increasing interest in intensive poplar plantations to meet growing energy demands. Sphaerulina musiva is able to cause infection on leaves, resulting in defoliation and canker formation on stems. To gain a greater understanding of the different responses of poplar species to infection caused by the naturally co-evolved Sphaerulina species, RNA-seq was conducted on leaves of Populus deltoides, P. balsamifera and P. tremuloides infected with S. musiva, S. populicola and a new undescribed species, Ston1, respectively. The experiment was designed to contain the pathogen in a laboratory environment, while replicating disease development in commercial plantations. Following inoculation, trees were monitored for disease symptoms, pathogen growth and host responses. Genes involved in phenylpropanoid, terpenoid and flavonoid biosynthesis were generally upregulated in P. balsamifera and P. tremuloides, while cell wall modification appears to play an important role in the defense of P. deltoides. Poplar defensive genes were expressed early in P. balsamifera and P. tremuloides, but their expression was delayed in P. deltoides, which correlated with the rate of disease symptoms development. Also, severe infection in P. balsamifera led to leaf abscission. This data gives an insight into the large differences in timing and expression of genes between poplar species being attacked by their associated Sphaerulina pathogen.

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

    Science.gov (United States)

    Hodges, C F; Coleman, L W

    1984-06-01

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

  19. Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens.

    Science.gov (United States)

    Aylward, Frank O; Burnum, Kristin E; Scott, Jarrod J; Suen, Garret; Tringe, Susannah G; Adams, Sandra M; Barry, Kerrie W; Nicora, Carrie D; Piehowski, Paul D; Purvine, Samuel O; Starrett, Gabriel J; Goodwin, Lynne A; Smith, Richard D; Lipton, Mary S; Currie, Cameron R

    2012-09-01

    Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant neotropical herbivores cultivate symbiotic fungus gardens on large quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers. Using metagenomic and metaproteomic techniques, we characterize the bacterial diversity and physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter and Escherichia. We show that these bacterial communities possess genes associated with lignocellulose degradation and diverse biosynthetic pathways, suggesting that they play a role in nutrient cycling by converting the nitrogen-poor forage of the ants into B-vitamins, amino acids and other cellular components. Our metaproteomic analysis confirms that bacterial glycosyl hydrolases and proteins with putative biosynthetic functions are produced in both field-collected and laboratory-reared colonies. These results are consistent with the hypothesis that fungus gardens are specialized fungus-bacteria communities that convert plant material into energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities in the ecology and evolution of herbivorous metazoans.

  20. Occurrence of Bipolaris maydis leaf spot on tanzania guineagrass in the north region of the Mato Grosso state

    Directory of Open Access Journals (Sweden)

    Tauan Rimoldi Tavanti

    2016-08-01

    Full Text Available The monoculture associated with the intensification of livestock results on appearance of diseases in forages, which can lead to significant losses. Symptomatic leaves of Tanzania guineagrass (Panicum maximum collected in Alta Floresta and Nova Guarita, Mato Grosso State, Brazil, were analyzed in the Plant Pathology Laboratory of UNEMAT/Alta Floresta. Fragments of diseased tissues previously disinfected in 70% ethanol and sodium hypochlorite to 1000 ppm solutions, were plated in a potato dextrose agar culture medium. The plates were stored at 25 °C and 12-hours photo period, for seven days. After this period Tanzânia guineagrass (Panicum maximum plants were inoculated with the pathogen from infected plants collected on both cities. To complete Koch's postulate, after the onset of symptoms, the pathogen was reisolated. The fungus Bipolaris maydis, causal agent of leaf spot was identified, based on the observation of fungal structures in the light microscope, the use of sort keys and the of Koch’s postulate.

  1. Genetic characterization and linkage disequilibrium mapping of resistance to gray leaf spot in maize(Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    Liyu; Shi; Xiangling; Lv; Jianfeng; Weng; Hanyong; Zhu; Changlin; Liu; Zhuanfang; Hao; Yu; Zhou; Degui; Zhang; Mingshun; Li; Xiaoke; Ci; Xinhai; Li; Shihuang; Zhang

    2014-01-01

    Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.

  2. Tobacco leaf spot and root rot caused by Rhizoctonia solani Kühn.

    Science.gov (United States)

    Gonzalez, Marleny; Pujol, Merardo; Metraux, Jean-Pierre; Gonzalez-Garcia, Vicente; Bolton, Melvin D; Borrás-Hidalgo, Orlando

    2011-04-01

    Rhizoctonia solani Kühn is a soil-borne fungal pathogen that causes disease in a wide range of plants worldwide. Strains of the fungus are traditionally grouped into genetically isolated anastomosis groups (AGs) based on hyphal anastomosis reactions. This article summarizes aspects related to the infection process, colonization of the host and molecular mechanisms employed by tobacco plants in resistance against R. solani diseases. Teleomorph: Thanatephorus cucumeris (Frank) Donk; anamorph: Rhizoctonia solani Kühn; Kingdom Fungi; Phylum Basidiomycota; Class Agaricomycetes; Order Cantharellales; Family Ceratobasidiaceae; genus Thanatephorus. Somatic hyphae in culture and hyphae colonizing a substrate or host are first hyaline, then buff to dark brown in colour when aging. Hyphae tend to form at right angles at branching points that are usually constricted. Cells lack clamp connections, but possess a complex dolipore septum with continuous parenthesomes and are multinucleate. Hyphae are variable in size, ranging from 3 to 17 µm in diameter. Although the fungus does not produce any conidial structure, ellipsoid to globose, barrel-shaped cells, named monilioid cells, 10-20 µm wide, can be produced in chains and can give rise to sclerotia. Sclerotia are irregularly shaped, up to 8-10 mm in diameter and light to dark brown in colour. Symptoms in tobacco depend on AG as well as on the tissue being colonized. Rhizoctonia solani AG-2-2 and AG-3 infect tobacco seedlings and cause damping off and stem rot. Rhizoctonia solani AG-3 causes 'sore shin' and 'target spot' in mature tobacco plants. In general, water-soaked lesions start on leaves and extend up the stem. Stem lesions vary in colour from brown to black. During late stages, diseased leaves are easily separated from the plant because of severe wilting. In seed beds, disease areas are typically in the form of circular to irregular patches of poorly growing, yellowish and/or stunted seedlings. Knowledge is scarce

  3. Resistance to Bacterial Leaf Blight in a Somaclonal Rice Mutant HX-3 at Cellular Level

    Institute of Scientific and Technical Information of China (English)

    GAO Dong-ying; ZHOU Yi-hong; HUANG Xue-qing; SUN Li-hua; LIU Ai-min

    2004-01-01

    The interaction between rice host and its pathogen Xanthomonas oryzae pv. oryzae (Xoo) at cellular level was studied by using a resistant somaclonal mutant HX-3 and its susceptable donor Minghui 63. After inoculation with Xoo strain Zhe 173 (Chinese pathotype Ⅳ), the activity of superoxide dismutase (SOD) and peroxidase (POD) in the callus of Minghui 63 was increased dramatically, and the active oxygen(O2 - .) was produced at a higher rate; Meanwhile, the callus grew slowly with the reduction of protein content. Compared to the activity of SOD and POD, the production rate of O2-. and the fresh weight in HX-3 callus varied little after the inoculation. It could be proposed that there were great differences between the resistance of HX-3 and Mighui 63 at cellular level. There was no difference detected concerning resistance to bacterial leaf blight in HX-3 between the plant and the callus.

  4. Impact of solar radiation exposure on phyllosphere bacterial community of red-pigmented baby leaf lettuce.

    Science.gov (United States)

    Truchado, Pilar; Gil, M Isabel; Reboleiro, Patricia; Rodelas, Belén; Allende, Ana

    2017-09-01

    Solar radiation has been identified as a stress factor affecting phyllosphere associated bacteria colonization and survival during primary production. In the present study, the impact of different solar radiation doses on the phyllosphere microbiota of red-pigmented baby leaf lettuce cultivated in open field under commercial conditions was evaluated. Four weeks before harvest, the growing field was divided into four plots; each one was consecutively covered with one-week-interval with a light-excluding plastic to reduce the sunlight exposure. Four different solar radiation treatments were generated and cumulative photosynthetically active radiation (PAR) was used to differentiate treatments as follows: 4889 ± 428 μmol/m(2)/s (uncovered), 4265 ± 356 μmol/m(2)/s (covered for 1 week), 3602 ± 225 μmol/m(2)/s (covered for 2 weeks) and 3115 ± 313 μmol/m(2)/s (covered for 3 weeks). The size and composition of the phyllosphere bacterial community were determined by cultivation-depended (plate count) and independent (qPCR) techniques. Exposure to decreased levels of cumulative PAR did not produce significant differences in total bacterial community size, regardless of the chosen quantification techniques. However, total bacteria size quantified by qPCR was around 3.5 orders of magnitude higher than those obtained by plate count. The observed differences between cultivation-depended and independent techniques could be attributed to the presence of non-viable or viable but non-culturable (VBNC) bacteria. The bacterial community structure was analyzed using temperature gradient gel electrophoresis (TGGE), and significant differences were detected when the four solar treatment were compared. A qPCR approach was applied to the quantification of specific bacterial phyla and classes, previously identified in the phyllosphere of plants available literature, confirming that Proteobacteria, Bacteroidetes, Actinobacterias and Firmicutes were the most abundantly

  5. Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

    Science.gov (United States)

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

    2015-05-01

    Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.

  6. Evaluation of triticale accessions for resistance to wheat bacterial leaf streak caused by Xanthomonas translucens pv. undulosa

    Science.gov (United States)

    The bacterium Xanthomonas translucens pv. undulosa (Xtu) causes bacterial leaf streak (BLS) on wheat and other small grains. Several triticale accessions were reported to possess high levels of resistance to wheat Xtu strains. In this study, we evaluated a worldwide collection of 502 triticale acces...

  7. Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens

    Energy Technology Data Exchange (ETDEWEB)

    Aylward, Frank O.; Burnum, Kristin E.; Scott, Jarrod J.; Suen, Garret; Tringe, Susannah G.; Adams, Sandra M.; Barry, Kerrie W.; Nicora, Carrie D.; Piehowski, Paul D.; Purvine, Samuel O.; Starrett, Gabriel J.; Goodwin, Lynne A.; Smith, Richard D.; Lipton, Mary S.; Currie, Cameron R.

    2012-09-01

    Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant Neotropical herbivores cultivate symbiotic fungus gardens on massive quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers in mature Atta colonies. Here we use metagenomic, and metaproteomic techniques to characterize the bacterial diversity and overall physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that, in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter, and Escherichia. We show that these bacterial communities possess genes commonly associated with lignocellulose degradation, and likely participate in the processing of plant biomass. Additionally, we demonstrate that bacteria in these environments encode a diverse suite of biosynthetic pathways, and that they may enrich the nitrogen-poor forage of the ants with B-vitamins, amino acids, and proteins. These results are consistent with the hypothesis that fungus gardens are highly-specialized fungus-bacteria communities that efficiently convert plant material into usable energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities to the ecology and evolution of herbivorous metazoans.

  8. Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis

    Directory of Open Access Journals (Sweden)

    Abdjad Asih Nawangsih

    2011-04-01

    Full Text Available Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis. X. oryzae pv. oryzae (Xoo causes bacterial leaf blight (BLB of rice (Oryza sativa L., a major disease that constrains production of the staple crop in many countries of the world. Identification of X. oryzae pv. oryzae (Xoo was conducted based on the disease symptoms, pathogenicity, morphological, physiological, and genetic characteristics of bacterial cultures isolated from the infected plants. Fifty bacterial isolates predicted as Xoo have been successfully isolated. They are aerobic, rod shaped, and Gram negative bacteria. The isolates were evaluated for their hypersensitivity in tobacco and pathogenicity in rice plant. Fifty isolates induced hypersensitive reaction in tobacco and showed pathogenicity symptom in rice in different length. Based on physiological test, hypersensitivity and pathogenicity reactions, three bacterial isolates strongly predicted as Xoo, i.e. STG21, STG42, and STG46, were non indole formation, non pigment fluorescent, hydrolyzed casein, catalase activity positive, but negative oxidase. Partial sequencing of 16S rRNA genes of STG21 and STG42 showed 80% and 82% homology with X. oryzae, respectively, while STG46 showed 84% homology with X. campestris. Mini-Tn5 transposon mutagenesis of STG21 generated one of the mutants (M5 lossed it’s ability to induce hypersensitive reaction in tobacco plant and deficient in pathogenicity on rice. The lesion length of rice leaf caused by the mutant M5 decreased up to 80%.

  9. INFLUENCE OF CULTURAL PRACTICES ON THE DEVELOPMENT OF GRAY LEAF SPOT (GLS ON MAIZE AT BAKO, WESTERN ETHIOPIA

    Directory of Open Access Journals (Sweden)

    Kedir Wako

    2012-12-01

    Full Text Available The experiment was conducted at Bako Agricultural Research Center from 2008 to 2009 cropping seasons in order to evaluate the effect of sowing dates and ploughing frequency on the development of Grey Leaf Spot (GLS on maize. The susceptible variety Phb 3253, with three sowing dates (early, optimum and late at 10 days interval and three ploughing treatments: Minimum tillage (once, farmer’s practice (three times ploughing and four times ploughing were used. All plots were uniformly treated with GLS infected crop residue before first ploughing. Trial was laid out in factorial arrangement in Randomized Complete Block Design (RCBD with three replications. Among the planting dates, the highest disease severity of 7.60, 7.44  & 7.00, (1-9 scale and Area Under Disease Progress Curve (AUDPC 305.83, 280.1 and 280.33 were recorded in early sown minimum (conservation tillage practices, while the lowest was with AUDPC 161.50, 196.50 and 222.67 in four times ploughed plots in 2007, 2008 and 2009 years respectively. The highest thousand seed weight and grain yield was observed in four times ploughed and in early sown plots, while the lowest thousand seed weights and grain yield were recorded in the conservation tillage practice. Four times ploughed and early sown fields had a mean yield advantage of 474.73kg (6.66% and a total yield advantage 2020.77kg (36.23.6% over three times ploughed and minimum tillage practices for the three seasons 2008-2009. In general higher disease severity, low thousand seed weight and grain yield were recorded for the conservation tillage compared to other practices. The overall results showed that four times ploughing result in superior maize grain yield performance compared to others as it has resulted in reducing the disease development.

  10. Systems genetics reveals a transcriptional network associated with susceptibility in the maize-grey leaf spot pathosystem.

    Science.gov (United States)

    Christie, Nanette; Myburg, Alexander A; Joubert, Fourie; Murray, Shane L; Carstens, Maryke; Lin, Yao-Cheng; Meyer, Jacqueline; Crampton, Bridget G; Christensen, Shawn A; Ntuli, Jean F; Wighard, Sara S; Van de Peer, Yves; Berger, Dave K

    2017-02-01

    We used a systems genetics approach to elucidate the molecular mechanisms of the responses of maize to grey leaf spot (GLS) disease caused by Cercospora zeina, a threat to maize production globally. Expression analysis of earleaf samples in a subtropical maize recombinant inbred line population (CML444 × SC Malawi) subjected in the field to C. zeina infection allowed detection of 20 206 expression quantitative trait loci (eQTLs). Four trans-eQTL hotspots coincided with GLS disease QTLs mapped in the same field experiment. Co-expression network analysis identified three expression modules correlated with GLS disease scores. The module (GY-s) most highly correlated with susceptibility (r = 0.71; 179 genes) was enriched for the glyoxylate pathway, lipid metabolism, diterpenoid biosynthesis and responses to pathogen molecules such as chitin. The GY-s module was enriched for genes with trans-eQTLs in hotspots on chromosomes 9 and 10, which also coincided with phenotypic QTLs for susceptibility to GLS. This transcriptional network has significant overlap with the GLS susceptibility response of maize line B73, and may reflect pathogen manipulation for nutrient acquisition and/or unsuccessful defence responses, such as kauralexin production by the diterpenoid biosynthesis pathway. The co-expression module that correlated best with resistance (TQ-r; 1498 genes) was enriched for genes with trans-eQTLs in hotspots coinciding with GLS resistance QTLs on chromosome 9. Jasmonate responses were implicated in resistance to GLS through co-expression of COI1 and enrichment of genes with the Gene Ontology term 'cullin-RING ubiquitin ligase complex' in the TQ-r module. Consistent with this, JAZ repressor expression was highly correlated with the severity of GLS disease in the GY-s susceptibility network.

  11. Non-nodulated bacterial leaf symbiosis promotes the evolutionary success of its host plants in the coffee family (Rubiaceae)

    DEFF Research Database (Denmark)

    Verstraete, Brecht; Janssens, Steven; Rønsted, Nina

    2017-01-01

    Every plant species on Earth interacts in some way or another with microorganisms and it is well known that certain forms of symbiosis between different organisms can drive evolution. Within some clades of Rubiaceae (coffee family), a specific plant-bacteria interaction exists in which non...... in the Late Miocene, a period when the savannah habi- tat is believed to have expanded on the African continent and herbivore pressure increased. The presence of bacterial leaf endophytes appears to be restricted to Old World lineages so far. Plant lineages with leaf endophytes show a significantly higher...

  12. 一份新的水稻斑点叶突变体spl32的鉴定和基因定位%Characterization of a Novel Spotted Leaf Mutantspl32 and Mapping ofSpl32(t) Gene in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    钟振泉; 罗文龙; 刘永柱; 王慧; 陈志强; 郭涛

    2015-01-01

    A dominant spotted-leaf mutant of rice was isolated from F2 (Yuejingsimiao 2/H4) population. The mutant, designated asspl32 (spotted-leaf 32), initiated brown spots on leaf apex at the panicle differentiation period, and then gradually spread them to whole leaf and sheath. Trypan blue staining indicated that the formation of spots was not caused by cell death. Taken normal green leaf plants segregated from heterozygous F5 as control (CK), we found seeds per panicle and seed setting rate of spotted leaf plants were significantly lower than these of CK. After appearance of spots, the POD activity and MDA content ofspl32 were significantly higher than these of CK, while photosynthetic pigment content inspl32was reduced, without significant changes in chlorophyll fluorescence parameters. The resistance to rice bacterial blight inspl32was greatly improved by inoculation ofXan-thomonas oryzae pv.oryzae at heading period. The spotted-leaf trait ofspl32was verified to be controlled by a dominant gene that temporarily designated asSpl32(t). The novel rice spotted-leaf genewas mapped between markers Ind-c and RM206 on chromo-some 11 with a F2 (02428/spl32) population.%从F2(粤晶丝苗2号/H4)群体中,鉴定出一份显性斑点叶突变体spl32(spotted leaf 32)。其叶片褐色斑点受自然光诱导,在幼穗分化期从叶尖逐渐扩散至叶鞘,台盼蓝染色表明斑点并非由细胞死亡引起。以从 F5杂合个体分离出的正常叶色植株为对照,斑点叶植株的穗粒数、结实率显著降低。斑点出现后, spl32的POD活性和MDA含量均显著高于对照;同时, spl32叶片光合色素含量降低,但荧光动力学参数并无显著变化。抽穗期人工接菌表明, spl32对水稻白叶枯病菌抗性较对照显著提高。遗传分析表明 spl32斑点性状由一个显性基因 Spl32(t)控制,利用 F2(02428/spl32)群体将其定位在第11染色体Ind-c和RM206之间,推测该基因为一个新的水稻斑点叶基因。

  13. TLC profiles and antibacterial activity of Glinus oppositifolius L. Aug. DC. (Molluginaceae leaf and stem extracts against bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Juliana Janet R. Martin-Puzon

    2015-07-01

    Full Text Available Objective: To determine the antibacterial activities and the thin-layer chromatography (TLC fingerprint profiles of leaf and stem extracts of Glinus oppositifolius L. Aug. DC (G. oppositifolius. Methods: The leaves and stems were extracted using chloroform, ethanol and methanol as solvents. The antibacterial activity of the extracts were evaluated through disc diffusion, minimum inhibitory concentration and bactericidal concentration assays against methicillinresistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended spectrum β-lactamase-producing, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamaseproducing Pseudomonas aeruginosa (P. aeruginosa and Acinetobacter baumanii (A. baumanii. The TLC separation was carried out on leaf and stem ethanol extracts in ethyl acetate: n-hexane solvent system. Distinct spots were examined under visible light, UV 254 nm, UV 366 nm and after spraying with vanillin-sulfuric acid. Results: The leaf extracts revealed antibacterial activities, inhibiting the growth of the nonresistant and multidrug-resistant strains of the Gram-negative bacteria Escherichia coli, P. aeruginosa and A. baumanii. The TLC fingerprint profiles demonstrated the presence of various phytochemicals in leaf and stem extracts. Leaf extracts exhibited more diverse constituents compared to stem extracts, but some constituents were similar in both plant parts. Conclusions: G. oppositifolius leaf extracts can be used as new, alternative sources of antimicrobials against non-resistant and multidrug-resistant strains of the Gram-negative bacteria Escherichia coli, P. aeruginosa and A. baumanii. The TLC profiles represent the chemical integrity of G. oppositifolius leaf and stem extracts which form an important and powerful tool for standardization, authentication, quality control and determination of bioactive components of G. oppositifolius in any formulation and in powder form.

  14. Response of leaf endophytic bacterial community to elevated CO2 at different growth stages of rice plant

    Directory of Open Access Journals (Sweden)

    Gaidi eRen

    2015-08-01

    Full Text Available Plant endophytic bacteria play an important role in plant growth and health. In the context of climate change, the response of plant endophytic bacterial communities to elevated CO2 at different rice growing stages is poorly understood. Using 454 pyrosequencing, we investigated the response of leaf endophytic bacterial communities to elevated CO2 (eCO2 at the tillering, filling and maturity stages of the rice plant under different nitrogen fertilization conditions (low nitrogen fertilization (LN and high nitrogen fertilization (HN. The results revealed that the leaf endophytic bacterial community was dominated by Gammaproteobacteria-affiliated families, such as Enterobacteriaceae and Xanthomonadaceae, which represent 28.7-86.8% and 2.14-42.6% of the total sequence reads, respectively, at all tested growth stages. The difference in the bacterial community structure between the different growth stages was greater than the difference resulting from the CO2 and nitrogen fertilization treatments. The eCO2 effect on the bacterial communities differed greatly under different nitrogen application conditions and at different growth stages. Specifically, eCO2 revealed a significant effect on the community structure under both LN and HN levels at the tillering stage; however, the significant effect of eCO2 was only observed under HN, rather than under the LN condition at the filling stage; no significant effect of eCO2 on the community structure at both the LN and HN fertilization levels was found at the maturity stage. These results provide useful insights into the response of leaf endophytic bacterial communities to elevated CO2 across rice growth stages.

  15. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

    Directory of Open Access Journals (Sweden)

    Tao Ding

    Full Text Available Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

  16. Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

    Science.gov (United States)

    Ding, Tao; Melcher, Ulrich

    2016-01-01

    Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

  17. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Directory of Open Access Journals (Sweden)

    Leonardo De La Fuente

    Full Text Available Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen.

  18. Biocontrol Potential of Streptomyces hydrogenans Strain DH16 toward Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

    Science.gov (United States)

    Manhas, Rajesh K.; Kaur, Talwinder

    2016-01-01

    Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v) of S. hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10%) and streptomycete cells significantly improved seed germination (75–80%) and vigor index (1167–1538). Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers. PMID:28018402

  19. Biocontrol Potential of Streptomyces hydrogenans strain DH16 Towards Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

    Directory of Open Access Journals (Sweden)

    Rajesh Kumari Manhas

    2016-12-01

    Full Text Available Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v of Streptomyces hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10% and streptomycete cells significantly improved seed germination (75-80% and vigour index (1167-1538. Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

  20. Biocontrol Potential of Streptomyces hydrogenans Strain DH16 toward Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus.

    Science.gov (United States)

    Manhas, Rajesh K; Kaur, Talwinder

    2016-01-01

    Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v) of S. hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10%) and streptomycete cells significantly improved seed germination (75-80%) and vigor index (1167-1538). Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

  1. Isolation and Identification of Corynespora cassiicola Causing Banana Leaf Spot Disease%香蕉棒孢霉叶斑病菌的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    林善海; 黄思良; 张贺; 漆艳香; 覃丽萍; 谢玲; 付岗

    2011-01-01

    Three isolates were obtained from banana leaf spot sanples collected from Nanning, Guangxi by tissue isolation.The pathogenicity of the isolates was confirmed based on Koch's postulates.The conidia and conidiophores produced on the PDA-incubated colonies became longer than those on naturally occurred banana leaf spots.The pathogenic isolate CATAS100 was identified as a member of Corynespora cassicola based on its morphological characters on PDA medium and rDNA-ITS (ribosomal DNA internal transcribed spacer) sequence.This is the first report on molecular identification of Corynespora cassiicola causing banana leaf spots in China.%从广西南宁市采集香蕉棒孢霉叶斑病样本,用常规组织分离法获得3个菌株,经柯赫氏法则验证确定其为香蕉叶斑病的病原菌.该菌的形态特征在分离培养前后变化较大,自然病斑上的分生孢子和分生孢子梗均较短,经PDA培养基分离培养后显著变长,培养后的病原菌彤态特征与前人对Corynespora cassiicola的描述一致.根据形态特征及rDNA-ITS区序列比对结果,确定该病原菌株为多主棒孢菌[Corynespora cassiicola(Berk &Curt)Wei].

  2. Interaction between workers during a short time window is required for bacterial symbiont transmission in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Marsh, Sarah E.; Thomas-Poulsen, Michael; Pinto-Tomás, Adrián;

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudon......Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry...... occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure...

  3. Autoregulation of nodulation interferes with impacts of nitrogen fertilization levels on the leaf-associated bacterial community in soybeans.

    Science.gov (United States)

    Ikeda, Seishi; Anda, Mizue; Inaba, Shoko; Eda, Shima; Sato, Shusei; Sasaki, Kazuhiro; Tabata, Satoshi; Mitsui, Hisayuki; Sato, Tadashi; Shinano, Takuro; Minamisawa, Kiwamu

    2011-03-01

    The diversities leaf-associated bacteria on nonnodulated (Nod(-)), wild-type nodulated (Nod(+)), and hypernodulated (Nod(++)) soybeans were evaluated by clone library analyses of the 16S rRNA gene. To analyze the impact of nitrogen fertilization on the bacterial leaf community, soybeans were treated with standard nitrogen (SN) (15 kg N ha(-1)) or heavy nitrogen (HN) (615 kg N ha(-1)) fertilization. Under SN fertilization, the relative abundance of Alphaproteobacteria was significantly higher in Nod(-) and Nod(++) soybeans (82% to 96%) than in Nod(+) soybeans (54%). The community structure of leaf-associated bacteria in Nod(+) soybeans was almost unaffected by the levels of nitrogen fertilization. However, differences were visible in Nod(-) and Nod(++) soybeans. HN fertilization drastically decreased the relative abundance of Alphaproteobacteria in Nod(-) and Nod(++) soybeans (46% to 76%) and, conversely, increased those of Gammaproteobacteria and Firmicutes in these mutant soybeans. In the Alphaproteobacteria, cluster analyses identified two operational taxonomic units (OTUs) (Aurantimonas sp. and Methylobacterium sp.) that were especially sensitive to nodulation phenotypes under SN fertilization and to nitrogen fertilization levels. Arbuscular mycorrhizal infection was not observed on the root tissues examined, presumably due to the rotation of paddy and upland fields. These results suggest that a subpopulation of leaf-associated bacteria in wild-type Nod(+) soybeans is controlled in similar ways through the systemic regulation of autoregulation of nodulation, which interferes with the impacts of N levels on the bacterial community of soybean leaves.

  4. Bacterial colonization of the phyllosphere of mediterranean perennial species as influenced by leaf structural and chemical features.

    Science.gov (United States)

    Yadav, R K P; Karamanoli, K; Vokou, D

    2005-08-01

    In this study, we assessed various leaf structural and chemical features as possible predictors of the size of the phyllosphere bacterial population in the Mediterranean environment. We examined eight perennial species, naturally occurring and coexisting in the same area, in Halkidiki (northern Greece). They are Arbutus unedo, Quercus coccifera, Pistacia lentiscus, and Myrtus communis (evergreen sclerophyllous species), Lavandula stoechas and Cistus incanus (drought semi-deciduous species), and Calamintha nepeta and Melissa officinalis (non-woody perennial species). M. communis, L. stoechas, C. nepeta, and M. officinalis produce essential oil in substantial quantities. We sampled summer leaves from these species and (1) estimated the size of the bacterial population of their phyllosphere, (2) estimated the concentration of different leaf constituents, and (3) studied leaf morphological and anatomical features and expressed them in a quantitative way. The aromatic plants are on average more highly colonized than the other species, whereas the non-woody perennials are more highly colonized than the woody species. The population size of epiphytic bacteria is positively correlated with glandular and non-glandular trichome densities, and with water and phosphorus contents; it is negatively correlated with total phenolics content and the thickness of the leaf, of the mesophyll, and of the abaxial epidermis. No correlation was found with the density of stomata, the nitrogen, and the soluble sugar contents. By regression tree analysis, we found that the leaf-microbe system can be effectively described by three leaf attributes with leaf water content being the primary explanatory attribute. Leaves with water content >73% are the most highly colonized. For leaves with water content 1.34 mg g(-1) d.w.) are more colonized, and leaves with the adaxial epidermis thicker than 20.77 microm are the least colonized. Although these critical attributes and values hold true only within

  5. Nucleotide sequences of a Korean isolate of apple stem grooving virus associated with black necrotic leaf spot disease on pear (Pyrus pyrifolia).

    Science.gov (United States)

    Shim, Hyekyung; Min, Yeonju; Hong, Sungyoul; Kwon, Moonsik; Kim, Daehyun; Kim, Hyunran; Choi, Yongmoon; Lee, Sukchan; Yang, Jaemyung

    2004-10-31

    Pear black necrotic leaf spot (PBNLS) is a disease of pears caused by capillovirus-like particles, which can be observed under the electron microscope. The disease was analyzed by Western blot analysis with antisera raised against apple stem grooving virus (ASGV) coat protein. cDNAs covering the entire genome were synthesized by RT-PCR and RACE using RNA isolated from Chenopodium quinoa infected with sap extracted from pear leaves carrying black necrotic spot disease. The complete genome sequence of the putative pear virus, 6497 nucleotides in length excluding the poly (A) tail, was determined and analyzed. It contains two overlapping open reading frames (ORFs). ORF1, spans from nucleotide position 37 to 6354, producing a putative protein of 241 kDa. ORF2, which is in a different reading frame within ORF1, begins at nucleotide 4788 and terminates at 5750, and produces a putative protein of 36 kDa. The 241 kDa protein contains sequences related to the NTP-binding motifs of helicases and RNA-dependent RNA polymerases. The 36-kDa protein contains the consensus sequence GDSG found in the active sites of several cellular and viral serine proteases. Morphological and serological analysis, and sequence comparison between the putative pear virus, ASGV, citrus tatter leaf virus and cherry virus A of the capillovirus suggest that PBNLS may be caused by a Korean isolate of ASGV.

  6. Pathovars of Pseudomonas syringae Causing Bacterial Brown Spot and Halo Blight in Phaseolus vulgaris L. Are Distinguishable by Ribotyping

    Science.gov (United States)

    González, Ana J.; Landeras, Elena; Mendoza, M. Carmen

    2000-01-01

    Ribotyping was evaluated as a method to differentiate between Pseudomonas syringae pv. phaseolicola and pv. syringae strains causing bacterial brown spot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with restriction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combination of data from both procedures yielded 19 combined ribotypes. Cluster analysis of the combined ribotypes differentiated the pathovars phaseolicola and syringae, as well as different clonal lineages within these pathovars. The potential of ribotyping to screen for correlations between lineages and factors such as geographical region and/or bean varieties is also reported. PMID:10653764

  7. Characterization of hypersensitive resistance to bacterial spot race T3 (Xanthomonas perforans) from tomato accession PI 128216.

    Science.gov (United States)

    Robbins, Matthew D; Darrigues, Audrey; Sim, Sung-Chur; Masud, Mohammed Abu Taher; Francis, David M

    2009-09-01

    Bacterial spot of tomato is caused by four species of Xanthomonas. The accession PI 128216 (Solanum pimpinellifolium) displays a hypersensitive reaction (HR) to race T3 strains (predominantely Xanthomonas perforans). We developed an inbred backcross (IBC) population (BC(2)S(5), 178 families) derived from PI 128216 and OH88119 (S. lycopersicum) as the susceptible recurrent parent for simultaneous introgression and genetic analysis of the HR response. These IBC families were evaluated in the greenhouse for HR to race T3 strain Xcv761. The IBC population was genotyped with molecular markers distributed throughout the genome in order to identify candidate loci conferring resistance. We treated the IBC population as a hypothesis forming generation to guide validation in subsequent crosses. Nonparametric analysis identified an association between HR and markers clustered on chromosome 11 (P P > 0.002). Further analysis of the IBC population suggested that markers on chromosome 6 and 11 failed to assort independently, a phenomenon known as gametic phase disequilibrium. Therefore, to validate marker-trait linkages, resistant IBC plants were crossed with OH88119 and BC(3)F(2) progeny were evaluated for HR in the greenhouse. In these subsequent populations, the HR response was associated with the chromosome 11 markers (P 0.25). Independent F(2) families were developed by crossing resistant IBC lines to OH8245, OH88119, and OH7530. These populations were genotyped, organized into classes based on chromosome 11 markers, and evaluated for resistance in the field. The PI 128216 locus on chromosome 11 provided resistance that was dependent on gene dosage and genetic background. These results define a single locus, Rx-4, from PI 128216, which provides resistance to bacterial spot race T3, has additive gene action, and is located on chromosome 11.

  8. Combined effects of elevated CO{sub 2} and natural climatic variation on leaf spot diseases of redbud and sweetgum trees

    Energy Technology Data Exchange (ETDEWEB)

    McElrone, Andrew J., E-mail: ajmcelrone@ucdavis.ed [USDA-ARS, Crops Pathology and Genetics Research Unit, 2154 RMI North, Davis, CA 95616 (United States); Department of Viticulture and Enology, University of California, Davis, CA 95616 (United States); Hamilton, Jason G. [Department of Biology, Ithaca College, Ithaca, NY 14850 (United States); Krafnick, Anthony J. [Department of Biology, Saint Joseph' s University, Philadelphia, PA 19131 (United States); Aldea, Mihai; Knepp, Rachel G.; DeLucia, Evan H. [Department of Plant Biology, University of Illinois, Urbana-Champaign, Urbana-Champaign, IL 61801 (United States)

    2010-01-15

    Atmospheric CO{sub 2} concentrations are predicted to double within the next century and alter climate regimes, yet the extent that these changes will affect plant diseases remains unclear. In this study conducted over five years, we assessed how elevated CO{sub 2} and interannual climatic variability affect Cercospora leaf spot diseases of two deciduous trees. Climatic data varied considerably between the five years and altered disease expression. Disease incidence and severity for both species were greater in years with above average rainfall. In years with above average temperatures, disease incidence for Liquidambar styraciflua was decreased significantly. When significant changes did occur, disease incidence and severity always increased under elevated CO{sub 2}. Chlorophyll fluorescence imaging of leaves revealed that any visible increase in disease severity induced by elevated CO{sub 2} was mitigated by higher photosynthetic efficiency in the remaining undamaged leaf tissue and in a halo surrounding lesions. - Climatic variation had a greater impact than elevated CO{sub 2} on Cercospora diseases, especially since leaf photosynthetic efficiency increased under elevated CO{sub 2}.

  9. Structure and Origin of Xanthomonas arboricola pv. pruni Populations Causing Bacterial Spot of Stone Fruit Trees in Western Europe.

    Science.gov (United States)

    Boudon, Sylvain; Manceau, Charles; Nottéghem, Jean-Loup

    2005-09-01

    ABSTRACT Xanthomonas arboricola pv. pruni, the causal agent of bacterial spot on stone fruit, was found in 1995 in several orchards in southeastern France. We studied population genetics of this emerging pathogen in comparison with populations from the United States, where the disease was first described, and from Italy, where the disease has occurred since 1920. Four housekeeping genes (atpD, dnaK, efp, and glnA) and the intergenic transcribed spacer region were sequenced from a total of 3.9 kb of sequences, and fluorescent amplified fragment length polymorphism (FAFLP) analysis was performed. A collection of 64 X. arboricola pv. pruni strains, including 23 strains from France, was analyzed. The X. arboricola pv. pruni population had a low diversity because no sequence polymorphisms were observed. Population diversity revealed by FAFLP was lower for the West European population than for the American population. The same bacterial genotype was detected from five countries on three continents, a geographic distribution that can be explained by human-aided migration of bacteria. Our data support the hypothesis that the pathogen originated in the United States and subsequently has been disseminated to other stone-fruit-growing regions of the world. In France, emergence of this disease was due to a recent introduction of the most prevalent genotype of the bacterium found worldwide.

  10. Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

    Directory of Open Access Journals (Sweden)

    Jared M LeBoldus

    Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

  11. Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

    Science.gov (United States)

    LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

    2013-01-01

    Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

  12. High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases.

    Science.gov (United States)

    Valentini, Giseli; Gonçalves-Vidigal, Maria Celeste; Hurtado-Gonzales, Oscar P; de Lima Castro, Sandra Aparecida; Cregan, Perry B; Song, Qijian; Pastor-Corrales, Marcial A

    2017-08-01

    Co-segregation analysis and high-throughput genotyping using SNP, SSR, and KASP markers demonstrated genetic linkage between Ur-14 and Co-3 (4) /Phg-3 loci conferring resistance to the rust, anthracnose and angular leaf spot diseases of common bean. Rust, anthracnose, and angular leaf spot are major diseases of common bean in the Americas and Africa. The cultivar Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and the gene cluster Co-3 (4) /Phg-3 containing two tightly linked genes conferring resistance to anthracnose and angular leaf spot, respectively. We used co-segregation analysis and high-throughput genotyping of 179 F2:3 families from the Rudá (susceptible) × Ouro Negro (resistant) cross-phenotyped separately with races of the rust and anthracnose pathogens. The results confirmed that Ur-14 and Co-3 (4) /Phg-3 cluster in Ouro Negro conferred resistance to rust and anthracnose, respectively, and that Ur-14 and the Co-3 (4) /Phg-3 cluster were closely linked. Genotyping the F2:3 families, first with 5398 SNPs on the Illumina BeadChip BARCBEAN6K_3 and with 15 SSR, and eight KASP markers, specifically designed for the candidate region containing Ur-14 and Co-3 (4) /Phg-3, permitted the creation of a high-resolution genetic linkage map which revealed that Ur-14 was positioned at 2.2 cM from Co-3 (4) /Phg-3 on the short arm of chromosome Pv04 of the common bean genome. Five flanking SSR markers were tightly linked at 0.1 and 0.2 cM from Ur-14, and two flanking KASP markers were tightly linked at 0.1 and 0.3 cM from Co-3 (4) /Phg-3. Many other SSR, SNP, and KASP markers were also linked to these genes. These markers will be useful for the development of common bean cultivars combining the important Ur-14 and Co-3 (4) /Phg-3 genes conferring resistance to three of the most destructive diseases of common bean.

  13. Etiology and intensity of leaf spot in wheat cultivars at three sites at Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Anderson Luiz Durante Danelli

    2011-09-01

    Full Text Available This study aimed to identify and quantify the causal agents of fungal leaf blights, and compare different assessment methods for disease quantification. The experiments were conducted with 20 medium cycle cultivars in Passo Fundo, Saint Augustus and Vacaria counties with three replications in randomized blocks. For evaluation 20 leaves were collected per plot, at flowering stage. Disease severity was estimated by the percent diseased leaf area and lesions number per leaf. For fungus etiology, twenty five discs of each leaf sample containing a lesion were subjected to a humid chamber. After three days incubation fungi identification was performed under a dissecting microscope. The mean incidence, number of lesions and severity data were subjected to analysis of variance and means compared by the Tukey’s multiple test at 5% significance level. The severity and lesions number were the most efficient criteria to fungal foliar disease, predominantly Bipolaris sorokiniana, Drechslera siccans, D. tritici-repentis and Stagonospora nodorum. The cultivars with the highest incidence rates were not the same as that presented the greatest number of injuries and severity. Join the appearance D. siccans and the resurgence of S. nodorum.

  14. Production of Gentisyl Alcohol from Phoma herbarum Endophytic in Curcuma longa L. and Its Antagonistic Activity Towards Leaf Spot Pathogen Colletotrichum gloeosporioides.

    Science.gov (United States)

    Gupta, Suruchi; Kaul, Sanjana; Singh, Baljinder; Vishwakarma, Ram A; Dhar, Manoj K

    2016-11-01

    Endophytes from medicinal plants represent a potential source of bioactive compounds. During the present investigation, fungal endophytes were isolated from turmeric (Curcuma longa), an important medicinal plant. A total of 207 endophytic fungal isolates were obtained from the rhizome of C. longa L. They were grouped into seven genera based on morphological and molecular data. The fungal endophytes of C. longa were evaluated for antifungal activity against Colletotrichum gloeosporioides, the causal organism of leaf spot of turmeric. The disease is a major cause for economic loss in turmeric cultivation. Endophytic Phoma herbarum showed significant activity against C. gloeosporioides and was therefore selected for further studies. A compound gentisyl alcohol was isolated from P. herbarum which showed effective antagonism against C. gloeosporioides. The organism could therefore be used as a biocontrol agent against C. gloeosporioides.

  15. Stable integration and expression of wasabi defensin gene in "Egusi" melon (Colocynthis citrullus L.) confers resistance to Fusarium wilt and Alternaria leaf spot.

    Science.gov (United States)

    Ntui, Valentine Otang; Thirukkumaran, Gunaratnam; Azadi, Pejman; Khan, Raham Sher; Nakamura, Ikuo; Mii, Masahiro

    2010-09-01

    Production of "Egusi" melon (Colocynthis citrullus L.) in West Africa is limited by fungal diseases, such as Alternaria leaf spot and Fusarium wilt. In order to engineer "Egusi" resistant to these diseases, cotyledonary explants of two "Egusi" genotypes, 'Ejagham' and NHC1-130, were transformed with Agrobacterium tumefaciens strain EHA101 harbouring wasabi defensin gene (isolated from Wasabia japonica L.) in a binary vector pEKH1. After co-cultivation for 3 days, infected explants were transferred to MS medium containing 100 mg l(-l) kanamycin to select transformed tissues. After 3 weeks of culture, adventitious shoots appeared directly along the edges of the explants. As much as 19 out of 52 (36.5%) and 25 out of 71 (35.2%) of the explants in genotype NHC1-130 and 'Ejagham', respectively, formed shoots after 6 weeks of culture. As much as 74% (14 out of 19) of the shoots regenerated in genotype NHC1-130 and 72% (18 out of 25) of those produced in genotype 'Ejagham' were transgenic. A DNA fragment corresponding to the wasabi defensin gene or the selection marker nptII was amplified by PCR from the genomic DNA of all regenerated plant clones rooted on hormone-free MS medium under the same selection pressure, suggesting their transgenic nature. Southern blot analysis confirmed successful integration of 1-5 copies of the transgene. RT-PCR, northern and western blot analyses revealed that wasabi defensin gene was expressed in transgenic lines. Transgenic lines showed increased levels of resistance to Alternaria solani, which causes Alternaria leaf spot and Fusarium oxysporum, which causes Fusarium wilt, as compared to that of untransformed plants.

  16. 天女木兰叶斑病病菌生物学特性研究%Research on Leaf Spot Pathogen Biological Characteristics of Magnolia sieboldii

    Institute of Scientific and Technical Information of China (English)

    刘波

    2016-01-01

    Using Magnolia sieboldii leaf spot pathogen as the test materials of different carbon and nitrogen sources on Magnolia leaf spot pathogen growth;the results show that:lactose and glucose is the carbon source for mycelial growth and ammonium nitrate is the nitrogen source;glucose is the most suitable carbon source for spore germination and ammonium nitrate is the nitrogen source;The suitable temperature for mycelial growth is 25℃ and for spore germination is 20~25℃;all-optical conditions suitable for mycelial growth and spore germination;the pH values for the mycelium growth and spore germination are 8 and 7,respectively.%以天女木兰叶斑病病菌为试材,研究不同碳、氮源对天女木兰叶斑病病菌生长的影响;试验结果表明:适合菌丝生长碳源是乳糖与葡萄糖;适合菌丝生长的氮源是硝酸铵;最适合孢子萌发的碳源是葡萄糖;适合孢子萌发的氮源是硝酸铵;25益适宜菌丝的生长,适宜孢子萌发的温度是20~25益;全光适宜菌丝的生长和孢子萌发。适合菌丝的生长和孢子萌发PH8与PH7。

  17. Foliar application of the leaf-colonizing yeast Pseudozyma churashimaensis elicits systemic defense of pepper against bacterial and viral pathogens

    Science.gov (United States)

    Lee, Gahyung; Lee, Sang-Heon; Kim, Kyung Mo; Ryu, Choong-Min

    2017-01-01

    Yeast associates with many plant parts including the phyllosphere, where it is subject to harsh environmental conditions. Few studies have reported on biological control of foliar pathogens by yeast. Here, we newly isolated leaf-colonizing yeasts from leaves of field-grown pepper plants in a major pepper production area of South Korea. The yeast was isolated using semi-selective medium supplemented with rifampicin to inhibit bacterial growth and its disease control capacity against Xanthomonas axonopodis infection of pepper plants in the greenhouse was evaluated. Of 838 isolated yeasts, foliar spray of Pseudozyma churashimaensis strain RGJ1 at 108 cfu/mL conferred significant protection against X. axonopodis and unexpectedly against Cucumber mosaic virus, Pepper mottle virus, Pepper mild mottle virus, and Broad bean wilt virus under field conditions. Direct antagonism between strain RGJ1 and X. axonopodis was not detected from co-culture assays, suggesting that disease is suppressed via induced resistance. Additional molecular analysis of the induced resistance marker genes Capsicum annuum Pathogenesis-Related (CaPR) 4 and CaPR5 indicated that strain RGJ1 elicited plant defense priming. To our knowledge, this study is the first report of plant protection against bacterial and viral pathogens mediated by a leaf-colonizing yeast and has potential for effective disease management in the field. PMID:28071648

  18. Autoregulation of Nodulation Interferes with Impacts of Nitrogen Fertilization Levels on the Leaf-Associated Bacterial Community in Soybeans ▿ †

    OpenAIRE

    2011-01-01

    The diversities leaf-associated bacteria on nonnodulated (Nod−), wild-type nodulated (Nod+), and hypernodulated (Nod++) soybeans were evaluated by clone library analyses of the 16S rRNA gene. To analyze the impact of nitrogen fertilization on the bacterial leaf community, soybeans were treated with standard nitrogen (SN) (15 kg N ha−1) or heavy nitrogen (HN) (615 kg N ha−1) fertilization. Under SN fertilization, the relative abundance of Alphaproteobacteria was significantly higher in Nod− an...

  19. Effect of Several Fungicides on Controlling Leaf Spot of Sugar Beet%几种杀菌剂防治甜菜褐斑病效果分析

    Institute of Scientific and Technical Information of China (English)

    杨安沛; 马俊义; 陈卫民; 孙桂荣

    2011-01-01

    [目的]筛选出防治甜菜褐斑病(Cercoapora belicola Sacc.)效果较好的杀菌剂为该病的有效防治提供理论依据.[方法]选择5种杀菌剂,进行防治甜菜褐斑病的田间小区试验.[结果]筛选出防治效果较好的杀菌剂是福星5000倍液和氟硅唑·多菌灵(12.5%·27.5%)悬浮剂,防效分别为60.80%和58.37%.与其他杀菌剂有显著性差异.5种杀菌剂防治时应连续喷药,间隔期7d,连续施药2次.I结论]5种杀菌剂均对甜菜褐斑病有一定的防治效果,防效最高的杀菌剂是福星、氟硅唑·多菌灵,可在生产上推广应用.%[ Objective]The aim of this study was to screen better fungicides for controlling sugar beet leaf apot . [Method] Selecting several fungicides to carry out experiment of controlling sugar beet leaf spot in the field. [ Result] Fuxing 5000 times and Flusdazole·Carbendazim ( 12 . 5% 27 . 5 % ) are better fungicides , their controlling efficiency exceeded 60 . 80% and 58 . 37% . They have significant differences from other fungicides. All fungicides slowly give their pesticide effects, the fungicides should be continually applied every 7 days by twice spraying , the control effect will be increased . [ Conclusion]Several fungicides have a preventive effect on the beet leaf spot, anti - efficient pbarmaceuticals : fuxing and Flusilazole · Carbendazim ( 12. 5% · 27 . 5 % ) have the highest control effects .They could be applied in production .

  20. Leaf-Associated Bacterial and Fungal Taxa Shifts in Response to Larvae of the Tree Hole Mosquito, Ochlerotatus triseriatus

    Science.gov (United States)

    Kaufman, Michael G.; Chen, Shicheng; Walker, Edward D.

    2014-01-01

    Larvae of the eastern tree hole mosquito, Ochlerotatus triseriatus (Say), and related container-breeding species are known to feed upon substrate-associated microorganisms. Although the importance of these microbial resources to larval growth has been established, almost nothing is known about the taxonomic composition and dynamics of these critical microbial food sources. We examined bacterial and fungal community compositional changes on oak leaves tethered in natural tree hole habitats of O. triseriatus. We eliminated larvae experimentally in a subset of the tree holes and examined 16S rDNA gene sequences for bacteria and ergosterol concentrations and 18S rRNA gene sequences for fungi collected from leaf material subsamples. Leaf ergosterol content varied significantly with time, but not treatment. Principal component analysis (PCA) was used to compare microbial taxonomic patterns found in leaves incubated with or without larvae present, and we found that larval presence affected both bacterial and fungal groups, either from loosely attached or strongly adherent categories. Bacterial communities generally grouped more tightly when larvae were present, and class level taxa proportions changed when larvae were present, suggesting selection by larval feeding or activities for particular taxa such as members of the Bacteroidetes, Alphaproteobacteria, and Betaproteobacteria classes. Fungal taxa composite scores also separated along PC axes related to the presence of larvae and indicated larval feeding effects on several higher taxonomic groups, including Saccharomycetes, Dothideomycetes, and Chytridiomycota. These results support the hypothesis that larval mosquito feeding and activities altered microbial communities associated with substrate surfaces, potentially leading to decreased food value of the resource and affecting decomposition of particulate matter in the system. PMID:17899246

  1. Mosquitocidal properties of Calotropis gigantea (Family: Asclepiadaceae) leaf extract and bacterial insecticide, Bacillus thuringiensis, against the mosquito vectors.

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Prasanna Kumar, Kanagarajan; Panneerselvam, Chellasamy; Mahesh Kumar, Palanisamy; Amerasan, Duraisamy; Subramaniam, Jayapal; Vincent, Savariar

    2012-08-01

    Calotropis gigantea leaf extract and Bacillus thuringiensis were tested first to fourth-instar larvae and pupae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The medicinal plants were collected from the area around Bharathiar University, Coimbatore, India. Calotropis gigantea leaf was washed with tap water and shade-dried at room temperature. An electrical blender powdered the dried plant materials (leaves). The powder 500 g of the leaf was extracted with 1.5 L of organic solvents of methanol for 8 h using a Soxhlet apparatus and filtered. The crude leaf extracts were evaporated to dryness in a rotary vacuum evaporator. The plant extract showed larvicidal and pupicidal effects after 24 h of exposure; no mortality was observed in the control group. For Calotropis gigantea, the median lethal concentration values (LC(50)) observed for the larvicidal and pupicidal activities against mosquito vector species Anopheles stephensi I to IV larval instars and pupae were 73.77, 89.64, 121.69, 155.49, and 213.79 ppm; Aedes aegypti values were 92.27, 106.60, 136.48, 164.01, and 202.56 ppm; and Culex quinquefasciatus values were 104.66, 127.71, 173.75, 251.65, and 314.70 ppm, respectively. For B. thuringiensis, the LC(50) values of I to IV larval instars and pupae of Anopheles stephensi were 37.24, 45.41, 57.82, 80.09, and 98.34 ppm; Aedes aegypti values were 42.38, 51.90, 71.02, 96.17, and 121.59 ppm; and Culex quinquefasciatus values were 55.85, 68.07, 94.11, 113.35, and 133.87 ppm, respectively. The study proved that the methanol leaf extract of Calotropis gigantea and bacterial insecticide B. thuringiensis has mosquitocidal property and was evaluated as target species of mosquito vectors. This is an ideal ecofriendly approach for the control of vector control programs.

  2. Some new and noteworthy diseases of poplars in India. [Botryodiplodia sett-rot; Alternaria tip blight; Cladosporium leaf spot; Fusarium pink incrustation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.

    1983-09-01

    Four new diseases of poplars namely Botryodiplodia sett-rott, Alternaria tip blight, Cladosporium leaf spot and Fusarium pink incrustation are described in this paper. Botryodiplodia palmarum causes sett-rott of poplars both at pre-sprouting and post-sprouting stage. The pathogen also causes mortality of poplar plants in the field within 4-6 weeks after planting. Alternaria stage of Pleuspora infectoria has been found as the cause of blackening and dying of growing tips and young leaves of a Populus sp. and P. deltoides in nurseries. Cladosporium humile has been recorded as the cause of brown spot followed by crumpling and premature shedding of leaves in P. ciliata, P. nigra and P. alba. The cause of Fusarium incrustation disease on P. cilata has been identified as Fusarium sp. of Gibbosum group. Pathogenicity of Botryodiplodia palmarum and Alternaria stage of Pleospora infectoria was confirmed by artificial inoculations. Brief descriptions of Alternaria, Cladosporium and Fusarium are also given. The paper also gives a short account of some noteworthy diseases recorded on poplars namely Ganoderma root rot, foliage ruts and stem cankers. Ganoderma root-rot is found to reach alarming proportions in closely spaced poplar plantations. Melampsora ciliata, an indigenous rust, is found to attack mainly clones of P. deltoides, P. yunnanensis, P. trichocarpa, P. alba and some cultivars of P. x euramericana in nurseries. A brief account of three types of stem cankers i.e. cankers due to pink disease fungus, Corticium salmonicolor, sun-scaled cankers and cankers associated with slime flux on various clones of P. deltoides is also given.

  3. Contribution of the drought tolerance-related stress-responsive NAC1 transcription factor to resistance of barley to Ramularia leaf spot.

    Science.gov (United States)

    McGrann, Graham R D; Steed, Andrew; Burt, Christopher; Goddard, Rachel; Lachaux, Clea; Bansal, Anuradha; Corbitt, Margaret; Gorniak, Kalina; Nicholson, Paul; Brown, James K M

    2015-02-01

    NAC proteins are plant transcription factors that are involved in tolerance to abiotic and biotic stresses, as well as in many developmental processes. Stress-responsive NAC1 (SNAC1) transcription factor is involved in drought tolerance in barley and rice, but has not been shown previously to have a role in disease resistance. Transgenic over-expression of HvSNAC1 in barley cv. Golden Promise reduced the severity of Ramularia leaf spot (RLS), caused by the fungus Ramularia collo-cygni, but had no effect on disease symptoms caused by Fusarium culmorum, Oculimacula yallundae (eyespot), Blumeria graminis f. sp. hordei (powdery mildew) or Magnaporthe oryzae (blast). The HvSNAC1 transcript was weakly induced in the RLS-susceptible cv. Golden Promise during the latter stages of R. collo-cygni symptom development when infected leaves were senescing. Potential mechanisms controlling HvSNAC1-mediated resistance to RLS were investigated. Gene expression analysis revealed no difference in the constitutive levels of antioxidant transcripts in either of the over-expression lines compared with cv. Golden Promise, nor was any difference in stomatal conductance or sensitivity to reactive oxygen species-induced cell death observed. Over-expression of HvSNAC1 delayed dark-induced leaf senescence. It is proposed that mechanisms controlled by HvSNAC1 that are involved in tolerance to abiotic stress and that inhibit senescence also confer resistance to R. collo-cygni and suppress RLS symptoms. This provides further evidence for an association between abiotic stress and senescence in barley and the development of RLS.

  4. NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

    Directory of Open Access Journals (Sweden)

    Yasuyo Sekiyama

    2017-01-01

    Full Text Available Cercospora leaf spot (CLS is one of the most serious leaf diseases for sugar beet (Beta vulgaris L. worldwide. The breeding of sugar beet cultivars with both high CLS resistance and high yield is a major challenge for breeders. In this study, we report the nuclear magnetic resonance (NMR-based metabolic profiling of field-grown leaves for a subset of sugar beet genotypes harbouring different levels of CLS resistance. Leaves were collected from 12 sugar beet genotypes at four time points: seedling, early growth, root enlargement, and disease development stages. 1H-NMR spectra of foliar metabolites soluble in a deuterium-oxide (D2O-based buffer were acquired and subjected to multivariate analyses. A principal component analysis (PCA of the NMR data from the sugar beet leaves shows clear differences among the growth stages. At the later time points, the sugar and glycine betaine contents were increased, whereas the choline content was decreased. The relationship between the foliar metabolite profiles and resistance level to CLS was examined by combining partial least squares projection to latent structure (PLS or orthogonal PLS (OPLS analysis and univariate analyses. It was difficult to build a robust model for predicting precisely the disease severity indices (DSIs of each genotype; however, GABA and Gln differentiated susceptible genotypes (genotypes with weak resistance from resistant genotypes (genotypes with resistance greater than a moderate level before inoculation tests. The results suggested that breeders might exclude susceptible genotypes from breeding programs based on foliar metabolites profiled without inoculation tests, which require an enormous amount of time and effort.

  5. Faba Bean Can Adapt to Chocolate Spot Disease by Pretreatment with Shikimic and Salicylic Acids through Osmotic Adjustment, Solutes Allocation and Leaf Turgidity

    Directory of Open Access Journals (Sweden)

    Heshmat S. Aldesuquy

    2014-03-01

    Full Text Available This study investigated the effect of shikimic and salicylic acids at the concentrations of 0.4 and 0.7 mM, respectively, or their combination as phenolic compounds and Ridomil MZ at the concentration of 250 g/100 L as a fungicide on osmotic pressure (OP, solutes allocation, organic acids, inorganic ions and relative water content were quantified in Vicia faba leaves infected by Botrytis fabae. Pathogen induced noticeable decrease in osmotic pressure, total soluble sugar (TSS and inorganic osmolytes (i.e. Na+, K+, Ca2+, Mg2+ and Cl- while caused obvious increase in proline, total soluble nitrogen (TSN and organic acids (i.e. Keto and citric acids in water extract of the leaf of faba bean plants. Furthermore, pathogen caused marked decrease in relative water content (RWC of infected leaves and as a consequence the saturation water deficit (SWD was increased. Exogenous application of shikimic acid, salicylic acid or their combination could counteract the adverse effects of B. fabae on osmotic adjustment by inducing additional increase in proline, total soluble sugars, total soluble nitrogen and organic acids which in turn increase the osmotic pressure as well as relative water content in leaves of infected plants. Recovery of osmotic adjustment as well as leaf turgidity of infected host by using these chemical inducers may encourage the using of them as protective control means. The results of the present study showed also that the application of chemical inducers such as shikimic and salicylic acids or their interaction increased the resistance of Vicia faba against the chocolate spot disease.

  6. Mulberry leaf extract mediated synthesis of gold nanoparticles and its anti-bacterial activity against human pathogens

    Science.gov (United States)

    Adavallan, K.; Krishnakumar, N.

    2014-06-01

    Gold nanoparticles (Au-NPs) were synthesized at room temperature using Morus alba (mulberry) leaf extract as reducing and stabilizing agent. The development of plant mediated synthesis of nanoparticles is gaining importance due to its simplicity, low cost, non-toxicity, eco-friendliness, long term stability and reproducible aqueous synthesis method to obtain a self-assembly of nearly monodispersed Au-NPs. The formation and morphology of biosynthesized nanoparticles are investigated with the help of UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) techniques. Au-NPs formation was screened by UV-Vis spectroscopy through color conversion due to surface plasmon resonance band at 538 nm for Au-NPs. DLS studies revealed that the average size of Au-NPs was 50 nm. TEM studies showed the particles to be nearly spherical with few irregular shapes and particle size ranges 15-53 nm. The AFM image clearly shows the surface morphology of the well-dispersed Au-NPs with less than 50 nm. The high crystallinity of nanoparticles is evident from bright circular spots in the selected area electron diffraction (SAED) pattern. X-ray diffraction pattern showed high purity and face-centered cubic structure of Au-NPs. The FT-IR results indicate the presence of different functional groups present in the biomolecule capping the nanoparticles. Further, biosynthesized Au-NPs show strong zone of inhibition against Vibrio cholera (gram-negative) and Staphylococcus aureus (gram-positive) whereas, chemically synthesized Au-NPs and mulberry leaf extract exhibit a fair zone of inhibition.

  7. The mechanics of bacterial cluster formation on plant leaf surfaces as revealed by bioreporter technology

    NARCIS (Netherlands)

    Tecon, R.; Leveau, J.H.J.

    2012-01-01

    Bacteria that colonize the leaves of terrestrial plants often occur in clusters whose size varies from a few to thousands of cells. For the formation of such bacterial clusters, two non-mutually exclusive but very different mechanisms may be proposed: aggregation of multiple cells or clonal

  8. Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

    Directory of Open Access Journals (Sweden)

    Jacqueline M Benson

    2015-03-01

    Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR loci. Nested association mapping (NAM was used to identify 16 quantitative trait loci (QTL for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will

  9. Temporal Incubation Dynamic of Apple Leaf Brown Spot Caused byDiplocarpon mali%苹果褐斑病潜育动态

    Institute of Scientific and Technical Information of China (English)

    雍道敬; 李保华; 张延安; 王彩霞; 董向丽; 郭长飞

    2014-01-01

    褐斑病是导致苹果早期落叶的主要病害。研究旨在通过调查褐斑病的流行规律,为制定综合防治方案提供理论依据。2011和2012年,将褐斑病菌(Diplocarpon mali)分生孢子悬浮液分4-6次喷雾接种于富士苹果各龄期的叶片,接种后观测记录每个接种叶片第1个病斑出现的时间,每3 d观测一次,依此计算褐斑病在富士叶片上的平均潜育期、最短潜育期和显症历期。接种期间用全自动气象站,每30 min记录接种苹果树附近的气温、降雨量和相对湿度苹果褐斑病在富士苹果叶片上的平均潜育期23.8 d;最短潜育期为8-20 d,平均为13.6 d;显症历期为12-54 d,平均为31.3 d。在显症历期内,不同的时期显症病斑数不同。6、7月份接种叶片比8月份接种叶片的最短潜育期和显症历期长。防雨棚内培育叶片的最短潜育期和显症历期长于自然条件下培育的叶片的最短潜育期和显症历期。苹果褐斑病在基部老龄叶片上潜育期短,在代谢旺盛的梢部叶片上潜育期长。苹果生长前期(6、7月份)接种叶片的潜育期显著的长于生长后期(8、9月份)接种叶片的潜育期。苹果褐斑病的显症是一个动态的过程,其潜育时间和显症历期都相对较长。除取决于病原与寄主的组合外,苹果褐斑病潜育时间和显症历期的长短主要受叶片龄期、衰老程度和生理状态,即叶片抗病性的影响。6-9月份是苹果褐斑病的主要发病期,在此期间气温对褐斑病潜育期的影响不大,而降雨和高湿能促进病斑显症。在褐斑病菌侵染后的15 d,甚至20 d内,使用内吸治疗性杀菌剂能抑制绝大部分潜育期病斑发病。%[Objective] Leaf brown spot caused byDiplocarpon mali is the main disease causing defoliation of apple tree in early season. In order to understand the epidemics and design programs to control the disease, temporal

  10. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  11. The Cucumber leaf spot virus p25 auxiliary replicase protein binds and modifies the endoplasmic reticulum via N-terminal transmembrane domains

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, Kankana [University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4 (Canada); Theilmann, Jane; Reade, Ron; Sanfacon, Helene [Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0 (Canada); Rochon, D’Ann, E-mail: dann.rochon@agr.gc.ca [University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4 (Canada); Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0 (Canada)

    2014-11-15

    Cucumber leaf spot virus (CLSV) is a member of the Aureusvirus genus, family Tombusviridae. The auxiliary replicase of Tombusvirids has been found to localize to endoplasmic reticulum (ER), peroxisomes or mitochondria; however, localization of the auxiliary replicase of aureusviruses has not been determined. We have found that the auxiliary replicase of CLSV (p25) fused to GFP colocalizes with ER and that three predicted transmembrane domains (TMDs) at the N-terminus of p25 are sufficient for targeting, although the second and third TMDs play the most prominent roles. Confocal analysis of CLSV infected 16C plants shows that the ER becomes modified including the formation of punctae at connections between ER tubules and in association with the nucleus. Ultrastructural analysis shows that the cytoplasm contains numerous vesicles which are also found between the perinuclear ER and nuclear membrane. It is proposed that these vesicles correspond to modified ER used as sites for CLSV replication. - Highlights: • The CLSV p25 auxiliary replicase targets the endoplasmic reticulum (ER). • Targeting of CLSV p25 is associated with ER restructuring. • Restructuring of the ER occurs during CLSV infection. • CLSV p25 contains 3 predicted transmembrane domains 2 of which are required for ER targeting. • Vesicles derived from the ER may be sites of CLSV replication.

  12. Transformation of blackgram (Vigna mungo (L.) Hepper) by barley chitinase and ribosome-inactivating protein genes towards improving resistance to Corynespora leaf spot fungal disease.

    Science.gov (United States)

    Chopra, Rajan; Saini, Raman

    2014-12-01

    Blackgram (Vigna mungo (L.) Hepper), an important grain legume crop, is sensitive to many fungal pathogens including Corynespora cassiicola, the causal agent of corynespora leaf spot disease. In the present study, plasmid pGJ42 harboring neomycin phosphotransferase (nptII) a selectable marker gene, the barley antifungal genes chitinase (AAA56786) and ribosome-inactivating protein (RIP; AAA32951) were used for the transformation, to develop fungal resistance for the first time in blackgram. The presence and integration of transgene into the blackgram genome was confirmed by PCR and Southern analysis with an overall transformation frequency of 10.2 %. Kanamycin selection and PCR analysis of T0 progeny revealed the inheritance of transgene in Mendelian fashion (3:1). Transgenic plants (T1), evaluated for fungal resistance by in vitro antifungal assay, arrested the growth of C. cassiicola up to 25-40 % over the wild-type plants. In fungal bio-assay screening, the transgenic plants (T1) sprayed with C. cassiicola spores showed a delay in onset of disease along with their lesser extent in terms of average number of diseased leaves and reduced number and size of lesions. The percent disease protection among different transformed lines varies in the range of 27-47 % compare to control (untransformed) plants. These results demonstrate potentiality of chitinase and RIP from a heterologous source in developing fungal disease protection in blackgram and can be helpful in increasing the production of blackgram.

  13. Identification of SSR and RAPD markers linked to a resistance allele for angular leaf spot in the common bean (Phaseolus vulgaris line ESAL 550

    Directory of Open Access Journals (Sweden)

    Gilvan Ferreira da Silva

    2003-12-01

    Full Text Available The objective of this study was to identify RAPD and SSR markers associated with a resistant allele for angular leaf spot (Phaeoisariopsis griseola from the line 'ESAL 550', derived from the Andean 'Jalo EEP 558' cultivar, to assist selection of resistant genotypes. The resistant line 'ESAL 550' and the susceptible cultivar 'Carioca MG' were crossed to generate F1 and F2 populations. One hundred and twenty F2:3 families were evaluated. The DNA of the 12 most resistant families was bulked and the same was done with the DNA of the 10 most susceptible, generating two contrasting bulks. One RAPD and one SSR marker was found to be linked in coupling phase to the resistant allele. The SSR marker was amplified by the primer PV-atct001(282C, and its distance from the resistant allele was 7.6 cM. This is the most useful marker for indirect selection of resistant plants in segregating populations. The RAPD marker was amplified by the primer OPP07(857C linked in coupling phase to the resistant allele, and distant 24.4 cM. Therefore, this RAPD marker is not so useful in assisting selection because it is too far from the resistant allele.

  14. PRELIMINARY RESULTS OF THE STUDY ON THE SPREAD OF APPLE CHLOROTIC LEAF SPOT VIRUS (ACLSV IN DIFFERENT FRUIT TREE SPECIES IN KYUSTENDIL REGION OF BULGARIA

    Directory of Open Access Journals (Sweden)

    Aneliya BORISOVA

    2005-08-01

    Full Text Available The survey was carried out mostly in one of the main fruit tree growing regions of Bulgaria - Kyustendil, during the period of 2004-2005. A total of 632 trees corresponding to 50 apple, 27 pear, 19 plum, 4 peach, 9 sweet cherry and 4 sour cherry cultivars and 21 apricot elites were tested for the presence of Apple chlorotic leaf spot virus (ACLSV and six other viruses by ELISA. Samples for analyses were collected from different organs of plants: flowers, leaves or phloem tissues. In the present research, ACLSV was not found in pear, plum, apricot and sour cherry. The highest infection rate of the virus among the infected fruit tree species was in apple (73 % followed by sweet cherry (13.3 % and peach (11.76 %. The frequency of mixed infection was 43.2 % in the infected apple, 33.4 % in sweet cherry and 12.5 % in peach trees. The highest concentrations of ACLSV, measured by ELISA, were observed in naturally grown flower petals of apple and sweet cherry trees in May.

  15. HarpinPss-mediated enhancement in growth and biological control of late leaf spot in groundnut by a chlorothalonil-tolerant Bacillus thuringiensis SFC24.

    Science.gov (United States)

    Anil, Kondreddy; Podile, Appa Rao

    2012-04-20

    Chemical and biological approaches have been adopted to increase the growth and yield of crops and reduce loss due to diseases. We have adopted an integrated approach, where both direct antagonism and induced resistance were combined to reduce the incidence of late leaf spot (LLS) disease in groundnut caused by Phaeoisariopsis personata. Chitinolytic chlorothalonil-tolerant soil bacterium Bacillus thuringiensis SFC24 (Bt SFC24) was manipulated in vitro to express secretable form of elicitor protein harpin(Pss) of Pseudomonas syringae pv. syringae. Severity of the LLS decreased by 65% when the leaves were sprayed with B. thuringiensis expressing harpin(Pss) (Bt-pss). As seed treatment, there was an increase in growth of groundnut. Bt and Bt-pss accounted to 13% and 36% increase in shoot length. Expression of a secretable form of harpin(Pss) thus improved the ability of B. thuringiensis SFC24 to promote growth and control LLS in groundnut. In this new approach a chlorothalonil-tolerant chitinolytic bacterium was genetically engineered to secrete elicitor harpin(Pss) for dual benefit of growth promotion and disease control.

  16. Cruzamentos dialélicos de linhagens de milho sob condições de mancha de Phaeosphaeria Diallel crosses among maize lines under Phaeosphaeria leaf spot infestation

    Directory of Open Access Journals (Sweden)

    Maria Elisa Ayres Guidetti Zagatto Paterniani

    2000-06-01

    Full Text Available Híbridos simples de milho resultantes de cruzamentos dialélicos entre dez linhagens endogâmicas provenientes do CIMMYT foram avaliados em 4 locais do Estado de São Paulo (Estações Experimentais do IAC, em 1996/97, quanto à estabilidade e adaptabilidade da produtividade de grãos. Os ensaios foram instalados sob delineamento de blocos casualizados com três repetições, incluindo quatro testemunhas comerciais. Foi verificada grande previsibilidade da produção e adaptabilidade ampla (b=1,0 da maioria dos híbridos, indicando que o conjunto de linhagens é fonte potencial de híbridos heteróticos e de estabilidade satisfatória. Houve intensa severidade da mancha foliar de Phaeosphaeria maydis em Ribeirão Preto, considerada um dos fatores de estresse que mais contribuiu para a redução da qualidade ambiental. A doença foi avaliada cerca de 30 dias após o florescimento, através de uma escala de notas de 1 a 9, correspondendo a 0% e >80% de aréa foliar afetada na planta adulta, respectivamente. Houve uma tendência dos materiais mais resistentes à doença apresentarem valores de adaptabilidade menores que 1,0 (bSingle-cross hybrids of maize obtained from diallell crosses among ten inbred lines from CIMMYT were grown in four locations of the State of São Paulo, Brazil, during 1996/97, to evaluate stability and adaptability of grain yield. The experiments were set up in a randomized block design with three replications, including four comercial controls. High predictability of grain yield and general adaptability (b=1,0 was observed for most hybrids, indicating that the lines are a potential source of heterosis as well as for good adaptability. A severe infestation of Phaeosphaeria maydis leaf spot occured in Ribeirão Preto, representing a stress factor responsible for reduction of environmental quality. The disease was assessed about 30 days after flowering, using a scale of grades of 1 to 9, for 0% and 80% of the leaf area

  17. 香蕉真菌性叶斑病病原种群结构季节性变化研究%Seasonal variation in population structure of banana mycotic leaf spot pathogen

    Institute of Scientific and Technical Information of China (English)

    林善海; 黄思良; 岑贞陆; 覃丽萍; 黎起秦; 付岗

    2011-01-01

    [目的]研究香蕉叶斑病病原真菌种群结构的季节性变化,为香蕉叶斑病的流行学研究和防治提供理论依据.[方法]2009年6~10月,对南宁市金陵镇第1年生香蕉的真菌性叶斑病病原随机抽样,检测单个病斑的病原菌,并分析每个时期病原菌的种群结构.[结果]南宁市金陵镇香蕉真菌性叶斑病病原至少有9种,主要病原为香蕉暗双孢菌(Cordana musae).叶斑病类型以单一病原侵染为主,其独立侵染的检出率随着季节的变化呈先升后降趋势,最高峰(8月15目)达88.8%;复合侵染的叶斑病类型以两种病原共同侵染居多,检出率的变化趋势与单一病原相反;除Alternaria musae和Pestalotiopsis menezesiana外,其他7种病原之间可共同侵染香蕉;Cordana musae的总检出率呈振幅式上升,最高检出率达92.8%.[结论]季节变化是影响香蕉真菌性叶斑病病原种群结构的一个主要环境因子.Cordana musae是田间香蕉真菌性叶斑病病原菌的优势种,建议香蕉叶斑病的防治主要针对由Cordana musae引起的灰纹病.%[Objective]The present work was carried out to study the seasonal variation in population structure of banana mycotic leaf spot pathogen in order to provide information for its control. [Method]The effects of fungal pathogens, causing mycotic leaf spot diseases, were investigated on annual growth of banana plantations at Jinling Township (Nanning) from June to October, 2009. Pathogens of leaf spot were examined and the population structure was analyzed during each period. [Result]At least nine fungal pathogens of mycotic leaf spots of banana were observed, amongst which, the Cordana musae was the major pathogen. The single-pathogen-induced banana leaf spots (SBLS) were predominant. The detection rate of SBLS was slightly higher and declined rapidly along with seasonal variations, with the peak rate (88.8%) detected on 15 August. The co-infected banana leaf spots (CBLS) with two

  18. 水稻淡褐斑叶突变体lbsll的遗传分析与基因定位%Genetic Analysis and Gene Mapping of a Light Brown Spotted Leaf Mutant in Rice

    Institute of Scientific and Technical Information of China (English)

    奉保华; 杨杨; 施勇烽; 林璐; 陈洁; 黄奇娜; 魏彦林; Hei LEUNG; 吴建利

    2012-01-01

    A light brown spotted-leaf mutant of rice was isolated from an EMS-induced IR64 mutant bank. The mutant, designated as lbs.ll (light brown spotted-leaf 1), displayed light brown spot in the whole growth period from the first leaf to the flag leaf under natural summer field conditions. Agronomic traits including plant height, growth duration, seed-setting rate and 1000-grain weight of the mutant were significantly affected. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively termed lbsll (t), which was mapped to the short arm of chromosome 6. With developed SSR markers, the gene was finally delimited to an interval of 130 kb between markers RM586 and RM588. The Ibsll (t) gene is likely a novel rice spotted-leaf gene since no other similar genes have been i-dentified near the chromosomal region. The genetic data and recombination populations provided will facilitate further fine-mapping and cloning of the gene.%通过EMS诱变籼稻品种IR64获得一个稳定遗传的淡褐色斑点叶突变体lbsll(light broun spotted leaf1).在自然条件下,突变体播种后10~14 d,叶片上出现淡褐色斑点,随后逐渐扩散至全叶,第1叶至剑叶上均有淡褐色斑,为全生育期性状.斑点性状的表达对株高、生育期、结实率和千粒重等农艺性状具有显著的影响.遗传分析结果表明,该淡褐色斑点叶性状受一个隐性核基因控制.将突变体lbsll与正常叶色水稻Morobereken杂交构建F2定化群体,利用SSR标记,最终将该淡褐叶基因lbsll(t)定位在第6染色体短臂上一个约130 kb的区段上.定位的结果和发展的群体为该基因的进一步精细定位和克隆奠定了基础.

  19. Assessment of the Antimicrobial Activity of Olive Leaf Extract Against Foodborne Bacterial Pathogens

    Science.gov (United States)

    Liu, Yanhong; McKeever, Lindsay C.; Malik, Nasir S. A.

    2017-01-01

    Olive leaf extract (OLE) has been used traditionally as a herbal supplement since it contains polyphenolic compounds with beneficial properties ranging from increasing energy levels, lowering blood pressure, and supporting the cardiovascular and immune systems. In addition to the beneficial effects on human health, OLE also has antimicrobial properties. The aim of this work was to investigate the antimicrobial effect of OLE against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. Our results demonstrated that at a concentration of 62.5 mg/ml, OLE almost completely inhibited the growth of these three pathogens. In addition, OLE also reduced cell motility in L. monocytogenes, which correlated with the absence of flagella as shown by scanning electron microscopy. Moreover, OLE inhibited biofilm formation in L. monocytogenes and S. Enteritidis. Taken together, OLE, as a natural product, has the potential to be used as an antimicrobial to control foodborne pathogens. PMID:28210244

  20. 一种由麦根腐平脐蠕孢(Bipolaris sorokiniana)引起的柳枝稷叶斑病%A leaf spot disease of switchgrass caused by Bipolaris sorokiniana

    Institute of Scientific and Technical Information of China (English)

    马甲强; 袁庆华; 王瑜; 苗丽宏

    2016-01-01

    In 2014,switchgrass leaf spot was found on switchgrass in Shandong,China.In order to clear switchgrass leaf spot pathogen and it's taxonomic status,the pathogen was identified by morphology and molecular biology identification.According to the characteristics of conidia,conidiophores and conidia germination,it was identified as Bipolaris sorokiniana.Conidia were mostly straight,oblong,ovate,and olive-brown with 3 to 9 septa,it's two ends germinate.the dimensions were (13.5-25.5) μm × (21-78.5) μm.Conidiophores were single,sympodial,straight or geniculate,gray to brown,multiseptate,with 2 to 8 septa,Conidiophores were (45-112) μm × (6-8) μm.Sequence analysis of the rDNA-ITS region showed that the identity had 100% homology with Bipolaris sorokiniana in GenBank.The first report of leaf spot caused by Bipolaris sorokiniana on switchgrass in China.

  1. 玉米灰斑病及抗性研究%The Research Advance on Resistance to Grey Leaf Spot in Maize

    Institute of Scientific and Technical Information of China (English)

    曹国辉

    2009-01-01

    玉米灰斑病由尾孢菌引起.尾孢菌在玉米叶粉碳酸钙琼脂培养基上能够产生分生孢子.采用注射法可以进行人工接种,空气湿度大、温度适宜条件下利于病害发生.参考玉米大、小斑病国家调查标准,提出9级标准记载植株灰斑病发病级别.研究表明,以推广种植抗病品种为主,辅助以栽培管理的综合防治措施是防治玉米灰斑病的有效途径.目前,在我国主要玉米种质中,仅有PB类群种质表现为抗灰斑病,四平头、旅大红骨、PA等类群种质多表现为感病.随着玉米灰斑病危害加重,应加强玉米灰斑病抗性基因发掘、种质改良和创新研究.%Grey leaf spot(GLS) caused by Gercospora zeae-maydis is one of the important diseases in maize worldwide. In recent years, GLS occurs more and more severely and becomes the major disease in maize growing area of China. GLS can produce conidia on the medium of maize leaf powder plus CaCO3 agar and can be artificially inoculated by injection method. High humidity and suitable temperature are very conducive for the occurrence of GLS. According to the national evaluation standard of maize exserohilum turcicum and bipolarize maydays, 9 scales is suggest-ed for evaluating GLS severity. Development and cultivation of GLS resistant hybrids is the effective way to control GLS. Currently, PB germplasm is identified to be resistant to GLS, while Sipingtou, Lvdahonggu and PA germplasm are most susceptible. With GLS occurs more widely in China, gene identification and utilization and germplasm improvement for GLS resistance should be strengthened.

  2. Mancha de mirotécio em algodoeiro causada por Myrothecium roridum Myrothecium leaf spot of cotton caused by Myrothecium roridum

    Directory of Open Access Journals (Sweden)

    Maurício Conrado Meyer

    2006-09-01

    Full Text Available A mancha de mirotécio causada por Myrothecium roridum Tode ex Fr. foi observada em lavouras de algodão no sul do Maranhão, causando reduções de produtividade de até 60%. Os sintomas da doença são lesões necróticas, circulares, com estruturas salientes, os esporodóquios, de distribuição irregular. Foram observadas lesões nos pecíolos, brácteas, folhas e maçãs de algodoeiro cv. Deltapine Acala 90, Fibermax 966 e Sure Grow 821. O isolamento do fungo foi realizado em meio de cultura batata-dextrose-ágar (BDA. O teste de patogenicidade foi realizado em maçãs sadias, destacadas de algodoeiro cv. Fibermax 966, no estádio vegetativo R6, previamente desinfestadas. Foram testados 13 isolados de M. roridum, oito provenientes de algodão e cinco de soja. Avaliações das estruturas fúngicas foram realizadas com auxílio de microscópio óptico equipado com um micrômetro ocular. Os isolados causaram infecções em maçãs de algodão e destacou-se como mais agressivo o MA-75, proveniente de algodão, apresentando diâmetro médio de lesão de 1,3cm, aos sete DAI e 2,7cm aos 14 DAI. Todos os isolados formaram esporodóquios dispostos concenticamente em meio BDA. Os conídios são unicelulares, hialinos a oliváceos, abundantemente produzidos em massa verde-oliva a preta. Os conídios de isolados provenientes de algodão mediram, em média, 5,1µm x 1,5µm, e os obtidos de soja, 5,8µm x 1,5µm. Estes resultados relatam a ocorrência da mancha de mirotécio, causada por M. roridum, em lavouras comerciais de algodão no Brasil.Myrothecium leaf spot caused by Myrothecium roridum Tode ex Fr. was observed on cotton fields in Maranhão State, Brazil, causing yield reduction of up to 60%. Disease symptoms are lesions with concentric necrotic rings, with salient structures (sporodochia irregularly distributed. Symptoms were observed on petioles, bracts, leaves and bolls of cotton cultivars Deltapine Acala 90, Fibermax 966 and Sure Grow 821

  3. 玉米抗弯孢菌叶斑病的快速鉴定方法%Rapid Evaluation Method of Corn Curvularia Leaf Spot Disease

    Institute of Scientific and Technical Information of China (English)

    叶克苁; 郭新梅; 魏志刚; 张恩盈; 宋希云

    2011-01-01

    In order to find a primary evaluation method of maize for resistance to Curvularia leaf spot disease, the pathogenicity of ctude toxin and filtrate was compared, and the relationship between seedling growth and inbred lines' resistance was analyzed in this paper. The results showed that the content of protein and polycose in filtrate was more than that in crude toxin. In the same dilution rate,the ctude toxin and filtrate had no significant difference in pathogenicity. The filtrate inhibition to seeds germination and plantule and radicle growth was positive correlated with field resistance of inbred lines, so it could be used as a simple method to preliminary assess the resistance of inbred lines.%为了探寻一种室内初步鉴定玉米自交系弯孢菌叶斑病抗病性的方法,比较新月弯孢菌粗毒素与纱布过滤的菌液对玉米种子萌发的影响,分析种子生长抑制情况与田间抗病性的关系.结果表明,纱布过滤的菌液中蛋白质及多糖质量浓度高于粗毒素中两者的质量浓度,在稀释同等倍数的前提下,两者的致病力之间没有显著差异,且过滤的菌液对种子萌发、胚芽及胚根的生长抑制情况与田间抗病性的表现基本一致,可作为初步衡量玉米自交系弯孢菌叶斑病抗病性的方法.

  4. In Vitro Rumen Fermentation and Anti Mastitis Bacterial Activity of Diet Containing Betel Leaf Meal (Piper betle L.

    Directory of Open Access Journals (Sweden)

    A. A. Yamin

    2013-08-01

    Full Text Available The aims of this experiment was to study the inhibition effect of betel leaf meal (BLM addition into concentrate diet on mastitis causing bacteria and on rumen fermentation condition. The study consisted of five dietary treatments of BLM level in concentrate feed, i.e., 0%, 2%, 4%, 6%, and 8% and four replicates of each treatment. The treatment diets together with napier grass in ratio of 40 : 60 were fermented using rumen liquor. All treatments were examined their antibacterial activity before and after fermentation. After four hours fermentation, supernatant of each samples were analyzed for VFA, NH3, number of bacteria and protozoa. Dry matter (DM and organic matter (OM digestibility were analyzed after 48 h fermentation. The results showed that before fermentation, 8% BLM addition caused the bigest (P<0.05 inhibition diameter of Staphylococcus spp. growth compared to other lower levels. However after fermentation there were no significant differences among the addition levels of BLM. Two per cent of BLM addition produced higher VFA (P<0.05 than the other addition levels. Ammonia concentration, dry matter (DM and organic matter (OM digestibility were not different among the treatments. Addition of BLM significantly (P<0.01 decreased protozoa number, but did not affect bacterial count. It is concluded that the addition of 2% BLM in concentrate feed can be used effectively to inhibit the growth of mastitis causing bacteria (Staphylococcus spp. and does not disturb rumen fermentation condition.

  5. Development of bioformulation and delivery system of Pseudomonas fluorescens against bacterial leaf blight of rice (Xanthomonas oryzae pv. oryzae).

    Science.gov (United States)

    Jambhulkar, P P; Sharma, P

    2014-09-01

    Antagonistic potential of Pseudomonas fluorescens isolate RRb-11 has been evaluated against bacterial leaf blight (BLB) pathogen of rice in vitro, in vivo, microplot and field tests. RRb-11 isolate mass multiplied in substrates like talc and kaolinite powder and bran of barley, soybean and wheat to prepare suitable bioformulation. The maximum shelf life of P. fluorescens was recorded in talc based bioformulation up to 150 days after storage. In rhizosphere competence study, the root rhizosphere of talc, kaolinite and barley based bioformulation treated plants showed good survivability and competence even up to 90 days after treatment. In field study, the talc based bioformulation was applied and the best results were obtained when talc based bioformulation of P. fluorescens RRb-11 was applied as seed treatment, seedling root dip and soil application in combination which reduced the disease by 92.3 and 88.5% over control in the year 2009 and 2010, respectively. This treatment also produced maximum yield of 3.88 t ha(-1) i.e., 61% greater than control.

  6. Interaction between workers during a short time window is required for bacterial symbiont transmission in Acromyrmex leaf-cutting ants.

    Science.gov (United States)

    Marsh, Sarah E; Poulsen, Michael; Pinto-Tomás, Adrián; Currie, Cameron R

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudonocardia Actinobacteria exosymbiont on their bodies that produces antifungal compounds that help inhibit specialized parasites of the ants' fungal garden. Major workers emerge from their pupal cases (eclose) symbiont-free, but exhibit visible Actinobacterial coverage within 14 days post-eclosion. Using subcolony experiments, we investigate exosymbiont transmission within Acromyrmex colonies. We found successful transmission to newly eclosed major workers fostered by major workers with visible Actinobacteria in all cases (100% acquiring, n = 19). In contrast, newly eclosed major workers reared without exosymbiont-carrying major workers did not acquire visible Actinobacteria (0% acquiring, n = 73). We further show that the majority of ants exposed to major workers with exosymbionts within 2 hours of eclosion acquired bacteria (60.7% acquiring, n = 28), while normal acquisition did not occur when exposure occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure the defensive function within colonies, as well as specificity and partner fidelity in the ant-bacterium association.

  7. Are leaf glandular trichomes of oregano hospitable habitats for bacterial growth?

    Science.gov (United States)

    Karamanoli, K; Thalassinos, G; Karpouzas, D; Bosabalidis, A M; Vokou, D; Constantinidou, H-I

    2012-05-01

    Phyllospheric bacteria were isolated from microsites around essential-oil-containing glands of two oregano (Origanum vulgare subsp. hirtum) lines. These bacteria, 20 isolates in total, were subjected to bioassays to examine their growth potential in the presence of essential oils at different concentrations. Although there were qualitative and quantitative differences in the essential oil composition between the two oregano lines, no differences were recorded in their antibacterial activity. In disk diffusion bioassays, four of the isolated strains could grow almost unrestrained in the presence of oregano oil, another five proved very sensitive, and the remaining 11 showed intermediate sensitivity. The strain least inhibited by oregano essential oil was further identified by complete16s rRNA gene sequencing as Pseudomonas putida. It was capable of forming biofilms even in the presence of oregano oil at high concentrations. Resistance of P. putida to oregano oil was further elaborated by microwell dilution bioassays, and its topology on oregano leaves was studied by electron microscopy. When inoculated on intact oregano plants, P. putida was able not only to colonize sites adjacent to essential oil-containing glands, but even to grow intracellularly. This is the first time that such prolific bacterial growth inside the glands has been visually observed. Results of this study further revealed that several bacteria can be established on oregano leaves, suggesting that these bacteria have attributes that allow them to tolerate or benefit from oregano secondary metabolites.

  8. Implication of the bacterial endosymbiont Rickettsia spp. in interactions of the whitefly Bemisia tabaci with tomato yellow leaf curl virus.

    Science.gov (United States)

    Kliot, Adi; Cilia, Michelle; Czosnek, Henryk; Ghanim, Murad

    2014-05-01

    Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with bacterial load. Our work

  9. Intracellular distribution, cell-to-cell trafficking and tubule-inducing activity of the 50 kDa movement protein of Apple chlorotic leaf spot virus fused to green fluorescent protein.

    Science.gov (United States)

    Satoh, H; Matsuda, H; Kawamura, T; Isogai, M; Yoshikawa, N; Takahashi, T

    2000-08-01

    The 50 kDa protein (50KP) encoded by ORF2 of Apple chlorotic leaf spot virus (ACLSV) fused to green fluorescent protein (GFP) was expressed transiently in cells of Nicotiana occidentalis and Chenopodium quinoa leaves. Its intracellular distribution, cell-to-cell trafficking in leaf epidermis and tubule formation on the surface of protoplasts were analysed. The 50KP-GFP fluorescence was distributed as small irregular spots or a fibrous network structure on the periphery of epidermal cells and protoplasts of both plant species. In leaf epidermis of N. occidentalis, the protein spread from the cells that produced it into neighbouring cells in both young and mature leaves and targetted plasmodesmata in these cells. In contrast, GFP was restricted to single cells in most cases in mature leaves. When 50KP and GFP were co-expressed in leaf epidermis of N. occidentalis, GFP spread more widely from the initial cells that produced it than when GFP was expressed alone, suggesting that 50KP facilitated the cell-to-cell trafficking of GFP. 50KP-GFP was able to complement local spread of 50KP-deficient virus when expressed transiently in leaf epidermis of C. quinoa. Expression of 50KP-GFP in protoplasts resulted in the production of tubular structures protruding from the surface. Mutational analyses showed that the C-terminal region (aa 287-457) was not essential for localization to plasmodesmata, cell-to-cell trafficking, complementation of movement of 50KP-deficient virus or tubule formation on protoplasts. In contrast, deletions in the N-terminal region resulted in the complete disruption of all these activities.

  10. Comparative Genomic and Phenotypic Characterization of Pathogenic and Non-Pathogenic Strains of Xanthomonas arboricola Reveals Insights into the Infection Process of Bacterial Spot Disease of Stone Fruits.

    Science.gov (United States)

    Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M; Cubero, Jaime

    2016-01-01

    Xanthomonas arboricola pv. pruni is the causal agent of bacterial spot disease of stone fruits, a quarantinable pathogen in several areas worldwide, including the European Union. In order to develop efficient control methods for this disease, it is necessary to improve the understanding of the key determinants associated with host restriction, colonization and the development of pathogenesis. After an initial characterization, by multilocus sequence analysis, of 15 strains of X. arboricola isolated from Prunus, one strain did not group into the pathovar pruni or into other pathovars of this species and therefore it was identified and defined as a X. arboricola pv. pruni look-a-like. This non-pathogenic strain and two typical strains of X. arboricola pv. pruni were selected for a whole genome and phenotype comparative analysis in features associated with the pathogenesis process in Xanthomonas. Comparative analysis among these bacterial strains isolated from Prunus spp. and the inclusion of 15 publicly available genome sequences from other pathogenic and non-pathogenic strains of X. arboricola revealed variations in the phenotype associated with variations in the profiles of TonB-dependent transporters, sensors of the two-component regulatory system, methyl accepting chemotaxis proteins, components of the flagella and the type IV pilus, as well as in the repertoire of cell-wall degrading enzymes and the components of the type III secretion system and related effectors. These variations provide a global overview of those mechanisms that could be associated with the development of bacterial spot disease. Additionally, it pointed out some features that might influence the host specificity and the variable virulence observed in X. arboricola.

  11. Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity.

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B; Graham, James H; Setubal, João C; Wang, Nian

    2011-11-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity.

  12. Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificity ▿ #

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B.; Graham, James H.; Setubal, João C.; Wang, Nian

    2011-01-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity. PMID:21908674

  13. 广西香蕉真菌性叶斑病病原菌种群结构分析%Investigations on the fungal populations associated with banana leaf spot diseases in Guangxi

    Institute of Scientific and Technical Information of China (English)

    林善海; 黄思良; 覃丽萍; 付岗; 岑贞陆; 谢玲

    2011-01-01

    2009年2-3月对广西香蕉主产区真菌性叶斑病病原进行抽样鉴定.结果显示,广西香蕉真菌性叶斑病病原至少有10种,主要病原为Cordana musae,分布广,检出率为56.77%~92.19%;Corynespora cassiicola和Deightoniella torulosa为次,两种病原菌均主要集中在南宁地区,检出率分别为32.34%和22.61%;叶斑病类型以单一病原侵染为主,检出率为78.13%~92.19%;复合侵染的叶斑病类型以2种病原共同侵染居多.%Investigations on banana leaf spot fungal pathogens were conducted in major banana production areas in Guangxi between February and March in 2009. The results showed that at least 10 fungal pathogens were found in the banana leaf spot samples. Cordana musae was the most frequently observed fungal pathogen with a detection rate of 56.77%-92.19% in the samples. Corynespora cassiicola and Deightoniella torulosa were mainly observed in the samples collected from the plantations at Nanning City, with the detection rates of 32.34% and 22. 61%, respectively. The banana leaf spots with only a single pathogen were predominant (78.13%-92.19%) compared to those with two or more fungal pathogens.

  14. Identification and Gene Mapping of a Spotted-leaf Mutant hm197 in Rice%水稻斑点叶突变体hm197的鉴定及其基因定位

    Institute of Scientific and Technical Information of China (English)

    李小红; 吴建利; 施勇烽; 张晓波; 奉保华; 宋莉欣; 王惠梅; 徐霞; 黄奇娜; 郭丹

    2015-01-01

    A stable inherited rice spotted-leaf mutant hm197 was isolated from a diepoxybutane-induced IR64 mutant bank.Under natural conditions,brown lesions were first observed on the tips of the mutant leaves 10 weeks after sowing,and spread gradually downward to cover the whole leaf blades.Genetic analysis indicated that the mutant trait was controlled by a novel single recessive nuclear gene,tentatively termed as splhm97 ,located in the long arm of chromosome 4.Agronomic traits including the plant height,seed-setting rate and 1000-grain weight were significantly decreased in hm197 .The initiation of brown lesions in hm197 was induced by natural sun light.In addition,the photosynthetic pigment contents and net photosynthetic rate in the mutant were significantly lower than those in the wild type IR64.Histochemical analysis showed that H2 O2 and O2∸ accumulation were presented in and around the lesions in hm197 .Furthermore,senescence-related parameters including the activities of SOD,APX,total soluble protein and MDA contents were also significantly altered in the mutant while resistance to bacterial blight pathogens was largely enhanced in the mutant in contrast to the wild type IR64.%通过双环氧丁烷(diepoxybutane)诱变籼稻品种 IR64获得遗传稳定的水稻褐色斑点叶突变体hm197.在自然条件下,该突变体褐色斑点自播种后10周开始于叶尖出现,而后慢慢扩散至全叶.遗传分析表明,该褐色斑点性状受一对隐性核基因控制,暂名splhm197,并将其定位在第4染色体长臂上140 kb的区段内.与野生型IR64相比,突变体株高、结实率和千粒重等农艺性状均显著下降.遮光处理表明,hm197褐色斑点的形成受自然光照的诱导.此外,hm197光合色素含量和光合效率也比野生型显著降低.组织化学分析表明,突变体中有过氧化氢和大量超氧阴离子 O2∸的沉积.与 IR64相比, hm197叶片中清除氧自由基酶系统中 SOD和 APX活性极显著上升,其余

  15. DnaK as Antibiotic Target: Hot Spot Residues Analysis for Differential Inhibition of the Bacterial Protein in Comparison with the Human HSP70.

    Directory of Open Access Journals (Sweden)

    Federica Chiappori

    Full Text Available DnaK, the bacterial homolog of human Hsp70, plays an important role in pathogens survival under stress conditions, like antibiotic therapies. This chaperone sequesters protein aggregates accumulated in bacteria during antibiotic treatment reducing the effect of the cure. Although different classes of DnaK inhibitors have been already designed, they present low specificity. DnaK is highly conserved in prokaryotes (identity 50-70%, which encourages the development of a unique inhibitor for many different bacterial strains. We used the DnaK of Acinetobacter baumannii as representative for our analysis, since it is one of the most important opportunistic human pathogens, exhibits a significant drug resistance and it has the ability to survive in hospital environments. The E.coli DnaK was also included in the analysis as reference structure due to its wide diffusion. Unfortunately, bacterial DnaK and human Hsp70 have an elevated sequence similarity. Therefore, we performed a differential analysis of DnaK and Hsp70 residues to identify hot spots in bacterial proteins that are not present in the human homolog, with the aim of characterizing the key pharmacological features necessary to design selective inhibitors for DnaK. Different conformations of DnaK and Hsp70 bound to known inhibitor-peptides for DnaK, and ineffective for Hsp70, have been analysed by molecular dynamics simulations to identify residues displaying stable and selective interactions with these peptides. Results achieved in this work show that there are some residues that can be used to build selective inhibitors for DnaK, which should be ineffective for the human Hsp70.

  16. Field Control Effect of 40% Azoxystrobin Tebuconazole SC on Apple Ahernaria Leaf Spots%40%嘧菌酯·戊唑醇悬浮剂对苹果斑点落叶病田间药效试验

    Institute of Scientific and Technical Information of China (English)

    鞠志远; 郭彩霞; 宋晓东; 谢克虎; 张曰秋

    2014-01-01

    40%嘧菌酯·戊唑醇悬浮剂对苹果斑点落叶病田间药效试验结果表明:40%嘧菌酯·戊唑醇悬浮剂3000倍、4000倍、5000倍液对苹果斑点落叶病的田间防效分别为91.0%、89.8%、87.3%,均高于多抗霉素的防效,各处理间有极显著差异,在红富士苹果上安全无药害,可以推广应用。%The results of field control effect of 40% azoxystrobin tebuconazole SC on apple A hernaria leaf spots showed that when the concentration of 40%azoxystrobin tebuconazole SC was diluted into 3 000 times,4 000 times and 5 000 times,the field effects on the apple A ltermaria leaf spots were 91.0%、89.8%、87.3%respectively,and were all higher than that of polyoxin.It had significant differences between all the treatment.40%azoxystrobin tebuconazole SC was safe for Fuji apple without any injury and could be widely applied.

  17. Biological characteristics of the pathogen causing gray leaf spot of loquat%枇杷灰斑病菌的生物学特性

    Institute of Scientific and Technical Information of China (English)

    谷会; 陈维信; 刘爱媛; 冯淑杰; 齐颖

    2009-01-01

    为了抑制枇杷灰斑病菌[Pestalotiopsis eriobotryfolia(Guba)Chen et Chao]的生长发育,防治枇杷灰斑病害的发生,研究了温度、湿度、pH值、光照、营养对枇杷灰斑病菌生长、产孢和孢子萌发的影响.该菌在PDA培养基上菌丝生长的温度为8~36℃.最适24℃;产生分生孢子的温度为8~34℃,最适26℃;分生孢子萌发的温度为8~36℃,最适28℃.在pH 3~10的PDA培养基上该菌均能生长和产孢,产生分生孢子最适pH 4,分生孢子萌发和菌丝生长最适pH 5.分生孢子在饱和湿度或水滴中萌发快,相对湿度低于90%时不能萌发.麦芽糖、蔗糖对分生孢子萌发有促进作用.硫酸铵、磷酸铵、硝酸铵对分生孢子萌发有抑制作用.分生孢子在50℃温水中经10 min或55℃温水中经2 min处理完全失去活力.菌丝体在50℃温水中经15 min或55℃温水中经2 min处理完全失去活力.%The effect of temperature, pH,light, carbon source, nitrogen source and moisture on the mycelial growth, sporula-tion and conidial germination of loquat gray leaf spot fungus [Pestalotiopsis eriobotryfolia (Guba) Chen et Chao]was primarily studied. For the mycelia growth ofP. eriobotrffolia ,the range of temperatures was 8 to 36 ℃ ,the optimum being 24℃; and the range of pH was 3 to 10, the optimum being 5. For the sporulation, the range of temperatures was 8 to 34 ℃, the optimum being 26℃ ; and the range of pH was 3 to 10,the optimum being 4. For the conidial germination ,the range of temperature was 8 to 36℃, the optimum being 28 ℃; and the range of pH was 3 to lO,the optimum being 5. When the relative humidity reached 100% or in water,the percentage of conidial germination was the highest; the conidia were found not germinated when the RH was below 90%. The maltose, or sucrose could promote the conidial germination. The ammonium sulfate, ammo-nium phosphate,or ammonium nitrate could inhibit the conidial germination. The lethal temperature

  18. Bioefficacy of larvicdial and pupicidal properties of Carica papaya (Caricaceae) leaf extract and bacterial insecticide, spinosad, against chikungunya vector, Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Naresh Kumar, Arjunan; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-02-01

    The present study was carried out to establish the properties of Carica papaya leaf extract and bacterial insecticide, spinosad on larvicidal and pupicidal activity against the chikungunya vector, Aedes aegypti. The medicinal plants were collected from the area around Bharathiar University, Coimbatore, India. C. papaya leaf was washed with tap water and shade-dried at room temperature. An electrical blender powdered the dried plant materials (leaves). The powder (500 g) of the leaf was extracted with 1.5 l of organic solvents of methanol for 8 h using a Soxhlet apparatus and then filtered. The crude leaf extracts were evaporated to dryness in a rotary vacuum evaporator. The plant extract showed larvicidal and pupicidal effects after 24 h of exposure; however, the highest larval and pupal mortality was found in the leaf extract of methanol C. papaya against the first- to fourth-instar larvae and pupae of values LC(50) = I instar was 51.76 ppm, II instar was 61.87 ppm, III instar was 74.07 ppm, and IV instar was 82.18 ppm, and pupae was 440.65 ppm, respectively, and bacterial insecticide, spinosad against the first to fourth instar larvae and pupae of values LC(50) = I instar was 51.76 ppm, II instar was 61.87 ppm, III instar was 74.07 ppm, and IV instar was 82.18 ppm, and pupae was 93.44 ppm, respectively. Moreover, combined treatment of values of LC(50) = I instar was 55.77 ppm, II instar was 65.77 ppm, III instar was 76.36 ppm, and IV instar was 92.78 ppm, and pupae was 107.62 ppm, respectively. No mortality was observed in the control. The results that the leaves extract of C. papaya and bacterial insecticide, Spinosad is promising as good larvicidal and pupicidal properties of against chikungunya vector, A. aegypti. This is an ideal eco-friendly approach for the control of chikungunya vector, A. aegypti as target species of vector control programs.

  19. Fungitoxicidade de grupos químicos sobre Myrothecium roridum in vitro e sobre a mancha-de-mirotécio em algodoeiro Fungitoxicity of chemical groups on Myrothecium roridum in vitro and on myrothecium leaf spot on cotton plants

    Directory of Open Access Journals (Sweden)

    Juliano César da Silva

    2006-05-01

    Full Text Available O objetivo deste trabalho foi avaliar a fungitoxicidade de produtos pertencentes aos grupos dos benzimidazóis, triazóis, estrobilurinas, isoftalonitrilas e ditiocarbamatos sobre a germinação conidial e o crescimento micelial in vitro de isolados de Myrothecium roridum e, in vivo, sobre a severidade da mancha-de-mirotécio em plantas de algodoeiro. Nos testes in vitro os fungicidas foram solubilizados em meio BDA, utilizando-se as concentrações de 0,1, 1, 10 e 100 mg L-1 de ingrediente ativo. A fungitoxidade dos produtos foi avaliada por meio da ED50 (dose necessária para inibir 50% da germinação conidial ou crescimento micelial. Em casa de vegetação, estimou-se a severidade da mancha-de-mirotécio pela porcentagem de área foliar lesionada nas plantas de algodoeiro tratadas antes (preventivo e depois (curativo da inoculação do patógeno. Os fungicidas tiofanato metílico, carbendazim, metconazol, tiofanato metílico + clorotalonil, piraclostrobina + epoxiconazol, piraclostrobina + metiram, triflostrobina + propiconazol e tebuconazol inibiram com alta eficácia (ED50The objective of this work was to evaluate the toxicity of benzimidazoles, triazoles, strobilurins, isoftalonitrils and ditiocarbamats on Myrothecium roridum conidial germination and micelial growth in vitro, and the myrothecium leaf spot severity on cotton plants. On in vitro tests, fungicides were solubilized in PDA media at the following concentrations: 0.1, 1, 10 and 100 mg L-1. The toxicity of the products were evaluated by the ED50 rate (required for inhibiting 50% of the conidial germination or mycelial growth. In greenhouse tests, the severity of myrothecium leaf spot was quantified by measuring the leaf area affected by the pathogen in cotton plants sprayed before (preventive and after (curative the pathogen inoculation. The fungicides thiophanate methyl, carbendazim, metconazole, thiophanate methyl + chlorothalonil, pyraclostrobin + epoxyconazole, pyraclostrobin

  20. Novel components of leaf bacterial communities of field-grown tomato plants and their potential for plant growth promotion and biocontrol of tomato diseases.

    Science.gov (United States)

    Romero, Fernando M; Marina, María; Pieckenstain, Fernando L

    2016-04-01

    This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  1. Alguns aspectos epidemiológicos da mancha bacteriana (Xanthomonas spp. do tomateiro na região de Caçador/SC Some epidemiological aspects of bacterial spot (Xanthomonas spp. of tomato in Caçador/SC, Brazil

    Directory of Open Access Journals (Sweden)

    Leandro Luiz Marcuzzo

    2009-06-01

    Full Text Available Objetivando explorar alguns aspectos da epidemiologia da de orvalho e um período médio de 13 horas continuas de umidade mancha bacteriana do tomateiro, incitada por Xanthomonas spp., relativa e"90%. A população bacteriana epifítica oscilou nas 10 em Caçador/SC, um ensaio a campo foi conduzido com plantas semanas após o plantio, conforme as condições climáticas, no inoculadas antes do transplantio. A cada sete dias e durante 19 entanto após o inicio dos sintomas manteve-se estável. O semanas foi monitorada a população bacteriana epifítica, as progresso da doença foi representado pelo modelo logístico y = condições climáticas e a severidade na planta. Constatou-se que o 0.99964/(1+exp(10.35989-0.69762*x e devido a pratica de inicio da epidemia teve concomitância com início da maturação apenas 1 colheita semanal, a severidade em frutos foi alta, fisiológica dos frutos do primeiro cacho, sendo que 77 dias antes atingindo 30,22% com produtividade total de117,88 ton.ha-1. Este do início da colheita não houve sintomas nas folhas. Observou-se, estudo epidemiológico servirá de um indicativo para determinação que mesmo em condição de estiagem, houve acréscimo da doença do inicio da epidemia e será usado na validação de um sistema de devido ao constante molhamento foliar decorrente da formação previsão para a mancha bacteriana do tomateiro.Aiming to explore some epidemiological aspects of bacterial spot of tomato incited by Xanthomonas spp., a field experiment was carried out in Caçador, SC. Tomato plants were inoculated with a bacterial suspension before transplanting. At seven-day intervals the bacterial population on leaf surface and disease severity were monitored during 19 weeks. Daily weather records were registered during the crop season. It was observed that epidemic onset coincided with physiological maturation of the first fruit clusters. Leaves were symptomless until 77 days before harvest. It was

  2. SCAR Marker Resistance-related to Cucumber Alternaria Leaf Spot and Resistance Identification of Cucumber Germplasm%与黄瓜抗黑斑病基因连锁的SCAR标记及抗病资源筛选

    Institute of Scientific and Technical Information of China (English)

    王惠哲; 李淑菊; 杨瑞环; 管炜; 邓强; 曹明明

    2014-01-01

    In order to establish molecular marker-assisted selection system of cucumber alternaria leaf spot with F1,F2and BC1population between a susceptible parent(L 63) and a resistant parent(L 9),a co-dominant AFLP marker was successfully converted into a simple, applied and co-dominant SCAR marker. Special marker SCEM 126/122 were designed according to the sequence information of AFLP( E-CC/M-CAT) fragments. The marker was closely linked to the cucumber alternaria leaf spot resistance-related gene, and the genetic distance between the marker and the gene was 4. 4 cM. The marker could be useful in marker-assisted selection in cucumber breeding. The acquired SCAR marker had many advantages including fast,accurate,low cost,free from an environmental in-fluence et. 64 resistant germplasm were abtained from total 290. Application of the acquired marker will inhance cu-cumber alternaria leaf spot disease resistant germplasm evaluation.%为建立黄瓜抗黑斑病分子标记辅助育种体系,以黄瓜感黑斑病母本L 63和抗黑斑病父本L 9及其F1、F2分离群体为试材,将与黑斑病抗性相关基因连锁的一个共显性AFLP标记E-CC/M-CAT进行了测序,根据序列特点设计了特异的SCAR引物SCEM126/122,成功地转换成了简单实用的共显性SCAR标记,经验证该标记与黄瓜抗黑斑病相关基因连锁遗传距离为4.4 cM,可以作为黄瓜抗黑斑病辅助选择的标记。且该标记具有迅速、简便、成本低、不受环境条件限制的优点,扩增条带清晰,无杂带和拖尾现象,适合用于大量样本分析。利用引物SCEM126/122对290份材料进行抗病性检测,结果表明有64份抗病材料,为进行抗黑斑病黄瓜新品种的选育奠定了基础。

  3. Raças de Xanthomonas spp. associadas à mancha-bacteriana em tomate para processamento industrial no Brasil Races of Xanthomonas spp. associated to bacterial spot in processing tomatoes in Brazil

    Directory of Open Access Journals (Sweden)

    Alice Maria Quezado-Duval

    2004-03-01

    Full Text Available A grande diversidade genética dos agentes causadores da mancha-bacteriana dificulta sobremaneira o desenvolvimento de variedades de pimentão e tomate com resistência durável. Setenta e dois isolados de Xanthomonas spp. provenientes de campos comerciais de tomate para processamento industrial dos estados de Goiás, Minas Gerais, Pernambuco e Bahia foram classificados em raças com base nas reações de genótipos diferenciais de tomateiro (Walter, Hawaii 7998 e NIL 216 e de Capsicum (ECW [Early Calwonder], ECW-10R, ECW-20R, ECW-30R e PI235047. As plantas foram inoculadas no estádio de três a cinco folhas verdadeiras por infiltração de suspensão bacteriana (5 ´ 10(8 UFC/ml na superfície abaxial da folha. Em seguida, foram mantidas em câmara de crescimento em fotoperíodo de 12 h/12 h (luz/escuro a 28ºC. A reação de hipersensibilidade foi observada até 36 horas após a inoculação, dependendo do genótipo da hospedeira. Foram identificadas as raças T1P2, T1P8 e T3 em X. axonopodis pv. vesicatoria; a raça T2 em X. vesicatoria; e as raças T2P7 e T2P8 em X. gardneri. A presença dos genes avrRxv e avrXv3 nos isolados que causaram reação de hipersensibilidade em 'Hawaii 7998' (raça T1 e 'NIL 216' (raça T3, respectivamente, foi confirmada por reação em cadeia da polimerase (PCR usando iniciadores específicos. Este é o primeiro relato da ocorrência no Brasil das raças T3, T1P8, T2P7 e T2P8.The great genetic diversity of the causal agents of bacterial spot is the main problem to the development of tomato and pepper varieties with durable resistance. Seventy two strains of Xanthomonas spp. collected from commercial fields of processing tomatoes in the states of Goiás, Minas Gerais, Pernambuco, and Bahia were classified in races according to their reactions on differential genotypes of tomato (Walter, Hawaii 7998 and NIL 216 and Capsicum [ECW (Early Calwonder, ECW-10R, ECW-20R, ECW-30R and PI 235047]. Bacterial suspensions (5

  4. Characterization and Gene Fine Mapping of a Rice Dominant Spotted-leaf Mutant%一个水稻显性斑点叶突变体的鉴定和基因精细定位

    Institute of Scientific and Technical Information of China (English)

    郭丹; 施勇烽; 王惠梅; 张晓波; 宋莉欣; 徐霞; 贺彦; 郭梁; 吴建利

    2016-01-01

    A stable inherited rice spotted-leaf mutantHM113 was isolated from an EMS-induced IR64 mutant bank. Under natural conditions, brown lesions were observed on the leaves in three weeks after sowing and spread to the sheaths at the initial heading stage. Agronomic traits including the plant height, panicle length, number of panicles, number of filled grain/panicle, seed-setting rate and 1000-grain weight were decreased significantly inHM113. In addition, the photosynthetic pigment contents, net photo-synthetic rate and soluble protein content in the mutant were significantly lower than those in the wild type IR64, while the MDA content was similar to that in the wild-type. Activities of CAT and SOD were significantly lower and activity of POD was signifi-cantly higher in the mutant than in IR64. Histochemical analysis showed that cell death and ROS accumulation were occurred in and around the lesions inHM113. Furthermore, disease resistance to bacterial blight pathogens was significantly enhanced in the mutant in contrast to that in the wild type IR64. Expression of defense-related genes includingAOS2,PAL4,PR10,andPR1b was apparently up-regulated in the mutant. Genetic analysis indicated that the mutant trait was controlled by a novel single dominant nuclear gene, tentatively termedas SplHM113, which was detected to be located in a region around 308 kb flanked by RM21605 and RM418 on the long arm of chromosome 7. The data and populations obtained in the present study would facilitate the isolation and functional analysis ofSplHM113.%通过EMS (ethane methyl sulfonate)诱变籼稻品种IR64获得一个稳定遗传的显性斑点叶突变体HM113。在大田环境下,突变体褐色斑点在播种后3周的叶片上产生,始穗期扩散至叶鞘。与野生型IR64相比,突变体HM113的株高、结实率和千粒重等农艺性状显著下降,光合色素含量、净光合速率和可溶性蛋白含量显著降低。同时突

  5. Recognition of phomopsis vexans in solanum melongena based on leaf disease spot features%基于叶片病斑特征的茄子褐纹病识别方法

    Institute of Scientific and Technical Information of China (English)

    田凯; 张连宽; 熊美东; 黄志豪; 李就好

    2016-01-01

    目前对蔬菜病害的识别方法都有一定的局限性,难以满足现代农业要求。该文以计算机视觉技术为手段,结合图像处理与模式识别技术,重点分析了茄子病害叶片上褐纹病病斑的颜色、形状、纹理特征参数,提出了一种基于叶片病斑特征的茄子褐纹病识别方法。根据在HSI(hue-saturation-intensity)颜色空间中叶片上病斑色调不同的特点,利用H分量图像提取病斑,获取病斑图片,然后提取每个病斑区域的12个颜色参数、11个形状参数和8个纹理参数等共31个特征参数。再通过方差和主成分分析法选择20个分类能力强的特征参数组成分类特征向量,并随机选取35个非褐纹病病斑的特征向量与35个褐纹病病斑的特征向量组成的训练集,构建Fisher判别函数对测试集进行分类,试验结果表明,对茄子褐纹病的识别准确率达到90%,说明该识别方法可以对茄子叶部病害进行快速、准确识别,为田间开放环境下实现茄子病害实时检测提供了技术支撑。%Phomopsis vexans is one of the most devastating diseases of Solanum melongena. Early detection and prevention of crop diseases is critical to control the diseases, improve crop yields, reduce the economic losses and control pesticide pollution. Therefore, the research of recognition methods for crop diseases is necessary. This paper proposed a disease recognition method of phomopsis vexans in Solanum melongena, based on leaf disease spot features. In this method, computer vision technology was used as a means of digital image processing and pattern recognition technique, focusing on analysis of the diseased leaf spots of color, shape, texture parameters. Diseased sample image was collected through an image acquisition system which composed of FitPC and server with long-distance point-to-point transmission. The collected diseased leaf images were processed using a series of image pre

  6. Fine mapping and analysis of a candidate gene in tomato accession PI128216 conferring hypersensitive resistance to bacterial spot race T3.

    Science.gov (United States)

    Pei, Chengcheng; Wang, Hui; Zhang, Jieyun; Wang, Yuanyuan; Francis, David M; Yang, Wencai

    2012-02-01

    Bacterial spot caused by Xanthomonas euvesicatoria, X. vesicatoria, X. perforans and X. gardneri is one of the most destructive diseases in tomatoes (Solanum lycopersicum L.) growing in tropical and subtropical regions. Exploring resistance genes from diverse germplasm and incorporating them into cultivated varieties are critical for controlling this disease. The S. pimpinellifolium accession PI128216 was reported to carry the Rx4 gene on chromosome 11 conferring hypersensitivity and field resistance to race T3. To facilitate the use of marker-assisted selection in breeding and map-based cloning of the gene, an F(2) population derived from a cross between the susceptible variety OH88119 and the resistant accession PI128216 was created for fine mapping of the Rx4 gene. Using 18 markers developed through various approaches, we mapped the gene to a 45.1-kb region between two markers pcc17 and pcc14 on chromosome 11. A NBS-LRR class of resistance gene was identified as the candidate for the Rx4 gene based on annotation results from the International Tomato Annotation Group. Comparison of the genomic DNA sequences of the Rx4 alleles in PI128216 and OH88119 revealed a 6-bp insertion/deletion (InDel) and eight SNPs. The InDel marker was successfully used to distinguish resistance and susceptibility in 12 tomato lines. These results will facilitate cloning the Rx4 gene and provide a useful tool for marker-assisted selection of this gene in tomato breeding programs.

  7. On Epidemiological Characteristics of Leaf Spot Disease of Stevia rebaudiana and Screening of Germicides at Mianyang%四川绵阳地区甜叶菊叶斑病的发病特征与杀菌剂筛选

    Institute of Scientific and Technical Information of China (English)

    罗明华; 曹远东

    2012-01-01

    本试验主要调查了四川绵阳地区甜叶菊叶斑病的发病规律;采用叶面喷雾法,测定多菌灵、乙基托布津、代森锌、粉锈宁、百菌清防治甜叶菊叶斑病的效果。结果表明:①绵阳地区甜叶菊叶斑病在6月中旬开始出现,6月下旬为发病高峰,病情指数为28.3。②在试验药剂中,相同稀释度75%百菌清,50%乙基托布津,65%代森锌防治效果相似,显著优于50%多菌灵和15%粉锈宁。%The occurrence regularity of leaf spot disease of Stevia rebaudiana Bertoni were surveyed at Mianyang, Sichuan in this experiment, and Zineb, Carbendazim, Thiophenateethyl, Chlorothalonil were used to evaluate effects against leaf spot disease of Stevia rebaudianai. The results were that: ①the occurrence regularity was that it began to occur in the middle of June, the latter half of June was the peak season, and the average field disease index was 28.3 ; ② the control effects of 75% by Chlorothalonil WP ,65% by Zineb WP( 可湿 性粉), 50% by Thiophenateethyl WP , 15% by Triadimefon WP and 50% by Carbendazim WP.

  8. 云南河口地区香蕉褐缘灰斑病的发生规律研究%Occurrence Regularity of Banana Sigatoka Leaf Spot Disease in Hekou of Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    张建春; 邓成菊; 陈伟强; 李芹; 刘学敏; 杨绍琼; 王晓燕; 胡原鸿; 黄绍忠

    2013-01-01

    The study is about banana sigatoka leaf spot disease in Hekou of Yunnan province. The findings show that the occurrence and the rule of development of the disease are influenced by temperature and rainfall. The disease begins at spring, when the temperature rises and reaches peak between October and December. The degree of harm of the disease differs greatly between different geographic environments, disease index: eastern district (11.81) > central and southern district (10.40) >western district (7.94) but the basic rule is that the disease in low altitude districts begins earlier than high altitude districts and is more harmful than that of the low districts and the disease index decreased with the rises of altitude, which has certain guiding significance for agricultural production.%对云南河口地区香蕉褐缘灰斑病(Banana Sigatoka Leaf Spot Disease)进行研究,结果表明:病害的发生、发展规律主要受温度和降雨量的影响;春季气温回升时开始发病,10~11月危害达到高峰值;不同地理环境危害程度有明显差异,病情指数东部地区(11.81)>中南部地区(10.40)>西部地区(7.94),但危害的基本规律是低海拔地区比高海拔地区先发病,且发病程度比高海拔地区严重,病情指数随着海拔的升高而降低。

  9. Photosynthetic efficiency of healthy leaf area influenced by angular leaf spot severity in bean field/ Influência da severidade de mancha angular na eficiência fotossintética da área foliar sadia de feijoeiro, sob condições de campo

    Directory of Open Access Journals (Sweden)

    Cláudia Vieira Godoy

    2005-06-01

    Full Text Available This paper aimed to show the relationship among healthy leaf area, angular leaf spot severity and bean yield, under field conditions, indicating the influence of this relationship on photosynthetic efficiency of leaf tissue remaining on plants. Leaf area and severity of angular leaf spot [Phaeoisariopsis griseola (Sacc. Ferraris] of bean were weekly assessed, beginning at 30 days after emergence (DAE. Different levels of severity were reached varying the timing of fungicide spraying (fentin hydroxide 0.10% + tebuconazole 0.04%. Variations on total leaf area were consequence of natural variation on plants and also due to different physic and chemical soil conditions among plots. The relation between healthy leaf area duration (HAD and area under disease progress curve (AUDPC and yield (g m-2 presented R2=74.8% and healthy area absorption (HAA, AUDPC and yield (g m-2 presented R2=74.7%. Results indicated reduction of yield when severity (AUDPC was high, even in plots with same level of healthy leaf area. So, the disease influenced the photosynthetic efficiency of healthy leaf area, besides avoiding the production of the necrotic tissue.O objetivo do trabalho foi demonstrar, em parcelas experimentais sob condições de campo, a relação entre área foliar sadia, severidade de mancha angular e produção em feijoeiro indicando a influência desta relação na eficiência fotossintética do tecido foliar remanescentes nas plantas. Área foliar e severidade de mancha angular [Phaeoisariopsis griseola (Sacc. Ferraris] de feijoeiro foram avaliadas semanalmente, iniciando-se aos 30 dias após a emergência (DAE. Obtiveram-se diferentes níveis de severidade variando-se a data de início de aplicação da mistura fungicida (fentin hydroxide 0,10% + tebuconazole 0,04%. Variações na quantidade de área foliar foram obtidas em função da variação inerente entre plantas e das diferenças de condições físicoquímicas encontradas no solo das parcelas

  10. The 50-kDa protein of Apple chlorotic leaf spot virus interferes with intracellular and intercellular targeting and tubule-inducing activity of the 39-kDa protein of Grapevine berry inner necrosis virus.

    Science.gov (United States)

    Isogai, M; Saitou, Y; Takahashi, N; Itabashi, T; Terada, M; Satoh, H; Yoshikawa, N

    2003-03-01

    To understand why transgenic Nicotiana occidentalis plants expressing a functional movement protein (MP) of Apple chlorotic leaf spot virus (ACLSV) show specific resistance to Grapevine berry inner necrosis virus (GINV), the MPs of ACLSV (50KP) and GINV (39KP) were fused to green, yellow, or cyan fluorescent proteins (GFP, YFP, or CFP). These fusion proteins were transiently expressed in leaf cells of both transgenic (50KP) and nontransgenic (NT) plants, and the intracellular and intercellular trafficking and tubule-inducing activity of these proteins were compared. The results indicate that in epidermal cells and protoplasts from 50KP plant leaves, the trafficking and tubule-inducing activities of GINV-39KP were specifically blocked while those of ACLSV-50KP and Apple stem grooving virus MP (36KP) were not affected. Additionally, when 39KP-YFP and 50KP-CFP were coexpressed in the leaf epidermis of NT plants, the fluorescence of both proteins was confined to single cells, indicating that 50KP-CFP interferes with the cell-to-cell trafficking of 39KP-YFP and vice versa. Mutational analyses of 50KP showed that the deletion mutants that retained the activities described above still blocked cell-to-cell trafficking of 39KP, but the dysfunctional 50KP mutants could no longer impede cell-to-cell movement of 39KP. Transgenic plants expressing the functional 50KP deletion mutants showed specific resistance against GINV. In contrast, transgenic plants expressing the dysfunctional 50KP mutants did not show any resistance to the virus. From these results, we conclude that the specific resistance of 50KP plants to GINV is due to the ability of the 50KP to block intracellular and intercellular trafficking of GINV 39KP.

  11. Larvicidal efficacy of Catharanthus roseus Linn. (Family:Apocynaceae) leaf extract and bacterial insecticideBacillus thuringiensis againstAnopheles stephensi Liston

    Institute of Scientific and Technical Information of China (English)

    Chellasamy Panneerselvam; Kadarkarai Murugan; Kalimuthu Kovendan; Palanisamy Mahesh Kumar; Sekar Ponarulselvam; Duraisamy Amerasan; Jayapal Subramaniam; Jiang-Shiou Hwang

    2013-01-01

    Objective:To explore the larvicidal activity ofCatharanthus roseus(C. roseus) leaf extract and Bacillus thuringiensis(B. thuringiensis) against the malarial vectorAnopheles stephensi(An. stephensi), when being used alone or together.Methods:The larvicidal activity was assayed at various concentrations under the laboratory and field conditions.TheLC50 andLC90 values of theC. roseus leaf extract were determined by probit analysis.Results:The plant extract showed larvicidal effects after24 h of exposure;however, the highest larval mortality was found in the petroleum ether extract ofC. roseus against the first to fourth instars larvae withLC50=3.34,4.48, 5.90 and8.17 g/L, respectively;B. thuringiensis against the first to fourth instars larvae with LC50=1.72,1.93,2.17 and2.42 g/L, respectively; and the combined treatment withLC50=2.18,2.41, 2.76 and3.22 g/L, respectively.No mortality was observed in the control.Conclusions:The petroleum ether extract ofC. roseus extract andB. thuringiensis have potential to be used as ideal eco-friendly agents for the control ofAn. stephensi in vector control programs.The combined treatment with this plant crude extract and bacterial toxin has better larvicidal efficacy against An. stephensi.

  12. Elaboração e validação de escala diagramática para a cercosporiose do pimentão Development and validation of a diagrammatic key for Cercospora leaf spot of sweet pepper

    Directory of Open Access Journals (Sweden)

    Sami Jorge Michereff

    2006-09-01

    Full Text Available A cercosporiose do pimentão, causada pelo fungo Cercospora capsici, é uma importante doença que ocorre em condições tropicais. Devido à inexistência de métodos padronizados para quantificação desta doença em campo, uma escala diagramática com os níveis de 1,5; 3,5; 8,0; 16,5; 31,0 e 50% de área foliar lesionada foi elaborada e testada para a acurácia, a precisão e a reprodutibilidade das estimativas de severidade da cercosporiose do pimentão, sem e com a sua utilização. Na validação da escala diagramática, 50 folhas com diferentes níveis de severidade da doença, mensurados previamente com o programa AutoCAD®, foram avaliadas por 13 avaliadores, sem e com a utilização da escala diagramática. Foram realizadas duas avaliações com utilização da escala, com intervalo de sete dias, onde seqüências diferentes das mesmas folhas foram estimadas visualmente pelos mesmos avaliadores. A acurácia e a precisão de cada avaliador foi determinada por regressão linear simples, entre a severidade real e a estimada. Sem a escala, oito avaliadores superestimaram significativamente a severidade da doença. Com a escala, os avaliadores obtiveram melhores níveis de acurácia e precisão, embora quatro tendessem a superestimar a severidade, com os erros absolutos concentrando-se abaixo de 10%. Os avaliadores apresentaram boa repetibilidade e elevada reprodutibilidade das estimativas com a utilização da escala, o mesmo não sendo verificado sem a utilização desta. A escala diagramática proposta mostrou-se adequada para avaliação da severidade da cercosporiose do pimentão.Cercospora leaf spot of sweet pepper caused by the fungus Cercospora capsici is an important disease occurring in tropical conditions. Due to the inexistence of standard methods to quantify this disease in field conditions, a diagrammatic key including the levels 1.5, 3.5, 8.0,16.5, 31.0 and 50.0% of diseased leaf area was elaborated and tested for accuracy

  13. Reação de cultivares de trigo à ferrugem da folha e mancha amarela e responsividade a fungicidas Reaction of wheat cultivars to leaf rust and yellow spot and responsiveness to fungicides

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    Nédio Rodrigo Tormen

    2013-02-01

    Full Text Available Com o objetivo de avaliar a reação de cultivares de trigo à ferrugem da folha, causada por Puccinia triticina, e mancha amarela, causada por Drechslera tritici-repentis, e sua responsividade ao controle químico com fungicidas, foi conduzido experimento de campo durante os invernos de 2009 e 2010, Itaara-RS. As cultivares avaliadas foram 'FCEP 51', 'FCEP 52', 'CD 114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' e 'OR Pampeano'; na safra 2010, a cultivar 'CD 114' foi substituída pela OR Quartzo. Os tratamentos avaliados foram: P1 - testemunha sem aplicação de fungicida; P2 - fempropimorfe (560g ha-1 de i.a.; P3 - azoxistrobina + ciproconazol (60+24g ha-1 de i.a.; e P4 - piraclostrobina + metconazol (60+97,5g ha-1 de i.a.. Após a segunda aplicação, efetuaram-se avaliações semanais de severidade das doenças, cujos dados foram utilizados para o cálculo da Área Abaixo da Curva de Progresso da Doença (AACPD. Também foram determinados a produtividade e o peso do hectolitro. No que se refere à suscetibilidade às doenças, as cultivares estudadas apresentaram respostas distintas de um ano para o outro. Para ferrugem, o comportamento mostrou-se similar em ambos os anos, enquanto que, para mancha amarela, houve variação. Quanto à resposta ao controle químico, ocorreram variações de acordo com o patógeno e com o grau de suscetibilidade das cultivares. O uso integrado de resistência genética e controle químico mostrou-se mais efetivo para ferrugem da folha.Aiming to evaluate the susceptibility of wheat cultivars to leaf rust and yellow spot and their responsiveness to chemical fungicides, two field trials were carried out, during 2009 and 2010 winter's. The cultivars evaluated were: 'FCEP 51', 'FCEP 52', 'CD114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' and 'OR Pampeano'. In 2010, the 'CD 114' cultivar was replaced by Quartzo

  14. Use of Blood Smears and Dried Blood Spots for Polymerase Chain Reaction-Based Detection and Quantification of Bacterial Infection and Plasmodium falciparum in Severely Ill Febrile African Children.

    Science.gov (United States)

    Wihokhoen, Benchawan; Dondorp, Arjen M; Turner, Paul; Woodrow, Charles J; Imwong, Mallika

    2016-02-01

    Molecular approaches offer a means of testing archived samples stored as dried blood spots in settings where standard blood cultures are not possible. Peripheral blood films are one suggested source of material, although the sensitivity of this approach has not been well defined. Thin blood smears and dried blood spots from a severe pediatric malaria study were assessed using specific polymerase chain reaction (PCR) primers to detect non-typhoidal Salmonella (NTS; MisL gene), Streptococcus pneumoniae (lytA), and Plasmodium falciparum (18S rRNA). Of 16 cases of NTS and S. pneumoniae confirmed on blood culture, none were positive by PCR using DNA extracts from blood films or dried blood spots. In contrast, four of 36 dried blood spots and two of 178 plasma samples were PCR positive for S. pneumoniae, despite negative bacterial blood cultures, suggesting false positives. Quantitative assessment revealed that the effective concentration of P. falciparum DNA in blood films was three log orders of magnitude lower than for dried blood spots. The P. falciparum kelch13 gene could not be amplified from blood films. These findings question the value of blood PCR-based approaches for detection of NTS and S. pneumoniae, and show that stored blood films are an inefficient method of studying P. falciparum.

  15. Responses of three very large inducible GTPases to bacterial and white spot syndrome virus challenges in the giant fresh water prawn Macrobrachium rosenbergii.

    Science.gov (United States)

    Huang, Ying; Jin, Min; Yin, Shaowu; Ding, Zhengfeng; Wang, Wen; Ren, Qian

    2016-04-01

    Interferons (IFNs) are cytokines secreted by cells in response to invasion by pathogens, such as viruses, bacteria, parasites, or tumor cells. Very large inducible GTPases (VLIG) are the latest IFN-inducible GTPase family to be discovered and are the largest known GTPases of any species. However, VLIG proteins from invertebrates have yet to be characterized. In this study, three forms of VLIGs designated as MrVLIG1, MrVLIG2, and MrVLIG3 were cloned from the giant fresh water prawn Macrobrachium rosenbergii. MrVLIG1 has a 5445 bp open reading frame (ORF) encoding an 1814-amino acid protein. The complete nucleotide sequence of MrVLIG2 cDNA is 7055 bp long consisting of a 5757 bp ORF encoding a protein with 1918 amino acids. The full length of the MrVLIG3 gene consists of 5511 bp with a 3909 bp ORF encoding a peptide with 1302 amino acids. BLASTP and phylogenetic tree analyses showed that the three MrVLIGs are clustered into one subgroup and, together with other vertebrate VLIGs, into a branch. Tissue distribution analysis indicated that the mRNAs of the three MrVLIGs were widely expressed in almost all detected tissues, including the hemocytes, heart, hepatopancreas, gills, stomach, and intestine, with the highest expression in the hepatopancreas. They were also detected in the intestine but with relatively low expression levels. Quantitative real-time RT-PCR analysis showed that the mRNA transcripts of the MrVLIGs in the hepatopancreas were significantly expressed at various time points after infection with Vibrio parahaemolyticus and white spot syndrome virus. In summary, the three isoforms of VLIG genes participate in the innate immune response of the shrimps to bacterial and viral infections.

  16. MOSAIC, BACTERIAL SPOT AND BLIGHT IN PEPPER-REVIEW MOSAICO, PÚSTULA BACTERIANA E REQUEIMA DO PIMENTÃO – REVISÃO BIBLIOGRÁFICA

    Directory of Open Access Journals (Sweden)

    Francisco J. B. Reifschneider

    2007-09-01

    Full Text Available

    A review about sintomatology, etiology, epidemiology, control, inoculation and evaluation of mosaic (potato virus Y, bacterial spot (Xanthomonas campestris pv. vesicatoria and blight (Phytophthora capsici is presented.

    Aspectos relacionados à sintomatologia, etiologia, epidemiologia, controle, inoculação e avaliação de mosaico (vírus Y da batata, pústula bacteriana (Xanthomonas campestris pv. vesicatoria e requeima (Phytophthora capsici são abordados em revisão bibliográfica. Em diversos países, o mosaico do pimentão (Capsicum annuun L. é enfermidade importante (LANGE & HAMMI, 1977; WIJS, 1980; NAGAI, 1984 e em algumas localidades foi considerado o problema mais sério da cultura (LOCKHART & FISCHER, 1974. Dentre as bacterioses que afetam o pimentão, a que mais se destaca é a pústula bacteriana (KIMURA, 1984. Também a requeima ou murcha é problema em diversas regiões produtoras (KIMBLE & GROGANK 1960; BAZAN DE SEGURA, 1962; MATTA & GARIBALDI, 1972; ERHAD & HILLE, 1975; MATSUOKA ei alii, 1984. Essa revisão pretende abordar cada uma destas doenças, abrangendo aspectos desde sintomatologia até controle, de utilidade na elaboração de projetos de pesquisa que visem ao controle por resistência genética.

  17. Comparative transcriptome proifling of two maize near-isogenic lines differing in the allelic state for bacterial brown spot disease resistance

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-jun; Xu Li; ZHAO Pan-feng; LI Na; WU Lei; HE Yan; WANG Shou-cai

    2015-01-01

    The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hal (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated tran-scriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufifcient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identiifed to have signiifcantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveil ance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were deifned, providing the repertoire of candidate genes for further functional characterization and identiifcation of their regulation patterns during pathogen infection.

  18. Efeito de produtos químicos e biológicos sobre a mancha bacteriana, flora microbiana no filoplano e produtividade de pimentão Effects of chemical and biological products on bacterial spot, microbial flora and yield in bell pepper

    Directory of Open Access Journals (Sweden)

    Débora AG da Silva

    2006-06-01

    Itaipu and Magali R. The study was carried out under field conditions from May to December 2002. A randomized complete block experimental design was used with four replications in a 4 x 3 factorial design. Weekly assessments were made for plant height (cm; number of stems; total number of leaves; number of fallen leaves; number of leaves with visible symptoms; damaged leaf area (severity, and yield (t ha-1. The microbial population resident in the phyloplan and fruits was quantified at the same time. There was no effect of treatments on yield, but an effect was observed on plant growth, on leaf spot and on the microbial flora. Copper oxychloride inhibited plant development, reduced number of fallen leaves and decreased the bacterial flora. Agrobio stimulated plant growth and, like streptomycin sulfate + oxytetracycline, inhibited the bacterial population, except Bacillus sp., and fungi, except Cladosporium sp. in the phyloplan. Among the genotypes, the hybrid Magali R was significantly superior in plant vigor, yield and resistance to bacterial spot. The results suggest bactericidal activity of the Agrobio under field conditions.

  19. Mecanismos bioquímicos da defesa do algodoeiro à mancha de ramulária mediados pelo silício Biochemical aspects of cotton resistance to ramularia leaf spot mediated by silicon

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    Carmen Rosa da Silva Curvêlo

    2013-01-01

    plantas da cv. BRS Buriti supridas com Si, houve aumento nas atividades da QUI e da GLU aos 21 dai em relação às não supridas com Si. Conclui-se que a resistência do algodoeiro à mancha de ramulária foi bioquimicamente potencializada pelo Si, principalmente para as plantas da cv. NuOpal consideradas suscetíveis à mancha de ramulária.This study investigated the effect of silicon (Si on cotton resistance to ramularia leaf spot (Ramularia areola. Plants of cotton (cvs. NuOpal and BRS Buriti were grown in nutrient solution containing 0 (+Si or 2 mM Si L-1 (-Si and inoculated with a conidial suspension of R. areola at 30 days after emergence. The incubation period (IP, latent period (LP60, severity, number of lesions (NL per cm² of leaf area, lesion size (LS, foliar Si concentration and the activities of defense enzymes peroxidases (POX, polyphenoloxidases (PPO, chitinases (CHI, β-1,3-glucanases (GLU, and phenylalanine ammonia-lyases (PAL were evaluated. Data from severity were used to calculate the area under ramularia leaf spot progress curve (AURLSPC. Leaf Si concentration increased by 64% on plants supplied with Si compared to plants not supplied with this element. There were increases of 10 and 14.7% for IP and LP60, respectively, on plants supplied with Si. Reductions of 38.6 and 62.4% for NL and 17.2 and 26.6% for LS occurred, respectively, for plants from NuOpal and BRS Buriti cvs supplied with Si. AURLSPC was reduced by 35% for the +Si treatment compared to the -Si treatment. The concentration of total soluble phenolic compounds on plants of both cv. supplied with Si increased during the progress of ramularia, but the lowest values occurred for the -Si treatment until 18 days after inoculation (dai. The increase on the concentration of lignin derivatives was significant only for plants of cv. BRS Buriti infected by R. areola and supplied with Si. POX activity was higher on plants from the two cultivars supplied with Si compared to plants not supplied with

  20. Mecanismos bioquímicos da defesa do algodoeiro à mancha de ramulária mediados pelo silício Biochemical aspects of cotton resistance to ramularia leaf spot mediated by silicon

    Directory of Open Access Journals (Sweden)

    Carmen Rosa da Silva Curvêlo

    2013-03-01

    plantas da cv. BRS Buriti supridas com Si, houve aumento nas atividades da QUI e da GLU aos 21 dai em relação às não supridas com Si. Conclui-se que a resistência do algodoeiro à mancha de ramulária foi bioquimicamente potencializada pelo Si, principalmente para as plantas da cv. NuOpal consideradas suscetíveis à mancha de ramulária.This study investigated the effect of silicon (Si on cotton resistance to ramularia leaf spot (Ramularia areola. Plants of cotton (cvs. NuOpal and BRS Buriti were grown in nutrient solution containing 0 (+Si or 2 mM Si L-1 (-Si and inoculated with a conidial suspension of R. areola at 30 days after emergence. The incubation period (IP, latent period (LP60, severity, number of lesions (NL per cm² of leaf area, lesion size (LS, foliar Si concentration and the activities of defense enzymes peroxidases (POX, polyphenoloxidases (PPO, chitinases (CHI, β-1,3-glucanases (GLU, and phenylalanine ammonia-lyases (PAL were evaluated. Data from severity were used to calculate the area under ramularia leaf spot progress curve (AURLSPC. Leaf Si concentration increased by 64% on plants supplied with Si compared to plants not supplied with this element. There were increases of 10 and 14.7% for IP and LP60, respectively, on plants supplied with Si. Reductions of 38.6 and 62.4% for NL and 17.2 and 26.6% for LS occurred, respectively, for plants from NuOpal and BRS Buriti cvs supplied with Si. AURLSPC was reduced by 35% for the +Si treatment compared to the -Si treatment. The concentration of total soluble phenolic compounds on plants of both cv. supplied with Si increased during the progress of ramularia, but the lowest values occurred for the -Si treatment until 18 days after inoculation (dai. The increase on the concentration of lignin derivatives was significant only for plants of cv. BRS Buriti infected by R. areola and supplied with Si. POX activity was higher on plants from the two cultivars supplied with Si compared to plants not supplied with

  1. Indução de resistência em feijoeiro a mancha angular por extratos de micélio de Pycnoporus sanguineus Resistance induction in bean plants against angular leaf spot by extracts from Pycnoporus sanguineus mycelium

    Directory of Open Access Journals (Sweden)

    Clair Aparecida Viecelli

    2010-03-01

    Full Text Available O feijoeiro (Phaseolus vulgaris L. está entre as principais culturas da agricultura nacional e pode ser afetada por várias doenças, como a mancha angular causada por Pseudocercospora griseola. Com o objetivo de desenvolver métodos alternativos ao químico para o controle desta doença, verificou-se o potencial de extratos de micélio de Pycnoporus sanguineus para atividade antimicrobiana in vitro contra P. griseola e para indução de resistência e ativação de enzimas de defesa em feijoeiro, como peroxidase, polifenoloxidase e β-1,3-glucanase, além de sua influência nos teores de proteínas e clorofilas. Os experimentos in vitro e em casa de vegetação foram constituídos pelos extratos de micélio de P. sanguineus e dos controles água, acibenzolar-S-metil (ASM: 75 mg i.a./L e fungicida azoxystrobin (40 mg i.a./L. In vitro o extrato de micélio apresentou efeito sobre o crescimento micelial, a esporulação e a germinação de esporos de P. griseola. In vivo a severidade foi reduzida em 93% e 50% em casa de vegetação e a campo respectivamente, em relação ao controle água. A atividade das enzimas peroxidase e polifenoloxidase e os teores de proteínas e clorofilas foram maiores nas plantas tratadas com o extrato. Estes resultados indicam a eficiência de P. sanguineus para o controle alternativo da mancha angular do feijoeiro.Angular leaf spot, caused by the fungus Pseudocercospora griseola, is a major disease of common bean (Phaseolus vulgaris L. in Brazil. The objective of this research was to develop an alternative method for controlling this disease based on an aqueous extract of Pycnoporus sanguineus mycelium. It was evaluated the antimicrobial activity of the aqueous extract against P. griseola as well as its activity of resistance induction against angular leaf spot. The role of the plant defense enzymes peroxidase, polyphenol oxidase and β-1,3-glucanase, and the proteins and chlorophyll content was investigated. The

  2. Melhoramento do feijoeiro comum com grão tipo carioca, visando resistência à antracnose e à mancha angular Breeding of common bean with carioca type grain for the resistance to anthracnose and angular leaf spot

    Directory of Open Access Journals (Sweden)

    Mansuêmia Alves Couto

    2008-10-01

    Full Text Available Objetivou-se no trabalho, selecionar linhagens de feijoeiro comum que reunissem, além da alta produtividade, porte ereto e grãos do tipo Carioca, também a resistência à antracnose e à mancha angular. O material experimental constituiu-se de 143 linhagens oriundas de três famílias segregantes F1:4RC2 {[(G2333 X ESAL 696 X ESAL 696] X CI 140}. Foram conduzidos quatro experimentos em três localidades da região sul de Minas Gerais, avaliando-se a produção, o tipo de grão, o porte e a reação à mancha angular. A reação à antracnose foi determinada a partir de inoculações de plantas jovens de cada linhagem, com as raças 2047 e 1545, mantidas em câmara de nevoeiro por três dias e transferidas para casa de vegetação com irrigação por aspersão, a cada quatro horas. Selecionaram-se quatro linhagens com alta produtividade, porte mais arbustivo, grãos tipo carioca e com resistência à mancha angular (nota até 4. Uma das linhagens selecionada possui o alelo Co-4², outras duas possuem o alelo Co-7 de resistência à antracnose e a última, embora seja suscetível à antracnose, possui resistência à mancha angular (nota 3,97 e maior produtividade de grãos.Aiming to select common bean lines with high grain yield, Carioca grain type, upright plant habit and resistant to anthracnose and angular leaf spot, 143 lines were selected from three families of the cross F1:4RC2 {[(G2333 X ESAL 696 X ESAL 696] X CI 140}. The promising lines were selected based on the agronomical traits in four field experiments, set up in three places in Southern MG State using the square lattice design. The reaction of each line to the anthracnose was evaluated by inoculating the seedlings using the races 1545 and 2047, and kept in humid chamber during three days, and then moved to greenhouse with sprinkle irrigation every four hours. Four lines with high grain yield, upright plant habit, Carioca grain type, and resistance to angular leaf spot (score up

  3. Avaliação de extrato de algas no progresso temporal da mancha de Mycosphaerella em cultivares de morangueiro Evaluation of seaweed extract on temporal progress of Mycosphaerella leaf spot in strawberry cultivars

    Directory of Open Access Journals (Sweden)

    Cristiano Nunes Nesi

    2013-02-01

    Full Text Available Em morangueiros, a mancha das folhas, causada por Mycosphaerella fragariae, é uma das doenças mais comuns na cultura, o que torna importantes os estudos de controle alternativo e de cultivares, sobre o progresso da epidemia. Em busca de práticas alternativas para seu controle, avaliou-se o efeito de cultivares de morangueiro e do extrato da alga Ascophyllum nodosum, na expressão dos sintomas de mycosphaerella, além de avaliar o ajuste de modelos de crescimento para o progresso temporal da incidência e severidade da doença. Utilizou-se o extrato de algas a 29%, na dose de 2 L ha-1, aplicado no solo, na folha e em ambos. As cultivares Dover, Toyonoka, Albion, Camarosa, Ventana, Campinas, Tudla e Camino Real foram avaliadas, quinzenalmente, quanto a incidência e severidade da doença. Utilizou-se o delineamento inteiramente casualizado, com parcelas subdivididas e três repetições. Com os dados de incidência e severidade, calculou-se a área abaixo da curva de progresso da doença e utilizou-se a análise de variância para avaliar o efeito de cultivares e do extrato de algas. Aos dados do progresso temporal da incidência e da severidade, em cada cultivar, foram ajustados os modelos monomolecular, logístico e de Gompertz. O extrato de algas não apresentou efeito ou interação com cultivares, no controle da mycosphaerella. Houve efeito de cultivar com menor intensidade da doença, em Albion e Ventana, devido, principalmente, ao atraso na epidemia, pela redução do inóculo inicial efetivo. Aos dados de progresso temporal da incidência e da severidade ajustaram-se, respectivamente, os modelos logístico e monomolecular, para todas as cultivares.Leaf spot, caused by Mycosphaerella fragariae, is a common foliar disease infectious to a broad variety of strawberry cultivars. In a search for alternative control methods, seaweed extract from Ascophyllum nodosum was applied to strawberry cultivars and evaluated for its effect on

  4. Seleção de famílias de feijoeiro resistente à antracnose e à mancha-angular Selection of common bean families resistant to anthracnose and angular leaf spot

    Directory of Open Access Journals (Sweden)

    Marcelo Geraldo de Morais Silva

    2006-10-01

    Full Text Available O objetivo deste trabalho foi identificar famílias de feijoeiro com resistência a Colletotrichum lindemuthianum e Phaeoisariopsis griseola e com outros fenótipos agronômicos desejáveis. As famílias utilizadas foram obtidas do cruzamento entre a linhagem H91, portadora de três alelos de resistência à antracnose, com três famílias F2:5 resistentes à mancha-angular, derivadas da cultivar Jalo EEP 558. Foi utilizado o delineamento látice quadrado em todos os experimentos. Inicialmente, foram avaliadas 144 famílias F2:3, no inverno de 2004, em Lavras, MG, com base no tipo de grão. Foram selecionadas 80 famílias F2:4 e avaliadas com a testemunha BRSMG Talismã, no período das águas de 2004/2005, no mesmo local. Considerando-se o tipo de grão e a resistência à mancha-angular e antracnose, foram mantidas 48 famílias F2:5, que foram avaliadas na seca de 2005, em Lavras e Lambari, MG. Essas 48 famílias passaram por inoculação das raças 2047, 73 e 1545 de C. lindemuthianum, para verificação da presença dos alelos de resistência Co-4², Co-5 e Co-7, respectivamente. Foram identificados genótipos da maioria das 48 famílias, quanto à reação à antracnose, das quais se destacaram quatro, em relação ao tipo de grão semelhante ao 'Carioca', de porte ereto, produtividade elevada e resistência à mancha-angular.The objective of this work was to select common bean families resistant to Colletotrichum lindemuthianum and Phaeoisariopsis griseola and, also, with superior agronomical traits. Families used were obtained from crosses of H91 lineage, bearer of three alleles resistant to anthracnose, and F2;5 families derived from the cultivar Jalo EEP 558, which is resistant to angular leaf spot. Square lattice design was used in all experiments. Initially the F2:3 families (144 were evaluated in the winter of 2004, in Lavras county, MG, Brazil, based on grain type. Eighty families (F2:4 were selected and evaluated with the check

  5. Rocky Mountain Spotted Fever (For Parents)

    Science.gov (United States)

    ... Feeding Your 1- to 2-Year-Old Rocky Mountain Spotted Fever KidsHealth > For Parents > Rocky Mountain Spotted Fever Print A A A What's in ... en español La rickettsiosis maculosa About RMSF Rocky Mountain spotted fever (RMSF) is a bacterial infection that's ...

  6. Atividades de quitinase e beta-1,3-glucanase após eliciação das defesas do tomateiro contra a mancha-bacteriana Chitinase and beta-1,3-glucanase activities after the elicitation of tomato defenses against bacterial spot

    Directory of Open Access Journals (Sweden)

    Fábio Rossi Cavalcanti

    2006-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência de eliciadores biológicos e químicos sobre as atividades de duas proteínas relacionadas à patogênese (PR, quitinase e beta-1,3-glucanase, em folhas de tomateiro, e avaliar o potencial desses eliciadores na redução do progresso da mancha-foliar causada por Xanthomonas campestris pv. vesicatoria. Plantas de tomateiro da cultivar Santa Cruz Kada foram pulverizadas com: acibenzolar-S-metil (ASM; 0,2 g L-1; formulação biológica proveniente de biomassa cítrica, denominada Ecolife (5 mL L-1; suspensão de quitosana (MCp; 200 g L-1, proveniente de micélio de Crinipellis perniciosa; extrato aquoso de ramos de lobeira (Solanum lycocarpum infectados por C. perniciosa (VLA; 300 g L-1. As plantas foram desafiadas com um isolado virulento da bactéria, quatro dias depois das pulverizações. Plantas pulverizadas com extratos biológicos mostraram redução da mancha-bacteriana. ASM proporcionou 49,3% de proteção, e foi igual à MCp e Ecolife e superior ao VLA. Este último não diferiu significativamente de MCp e Ecolife. Observou-se maior atividade das duas enzimas nas plantas tratadas, principalmente nas primeiras horas após as pulverizações.The objective of this work was to assess the influence of foliar application of resistance inducers and the activation of plant pathogenesis-related (PR proteins, chitinases and beta-1,3-glucanases, against Xanthomonas campestris pv. vesicatoria, and evaluate the potential of these elicitors on the reduction of bacterial leaf spot. Tomato plants of the cultivar Santa Cruz Kada were sprayed with: acibenzolar-S-methyl (0.2 g L-1 ASM; Ecolife, a biological formulation based on citric biomass (5 mL L-1; chitosan suspension from Crinipellis perniciosa mycelium (MCp; 200 g L-1; an aqueous extract from branches of lobeira (Solanum lycocarpum infected with C. perniciosa (VLA; 300 g L-1. Plants were challenged with a virulent bacterial strain four days after

  7. Mutagenesis of beta-1,3-Glucanase Genes in Lysobacter enzymogenes Strain C3 Results in Reduced Biological Control Activity Toward Bipolaris Leaf Spot of Tall Fescue and Pythium Damping-Off of Sugar Beet.

    Science.gov (United States)

    Palumbo, Jeffrey D; Yuen, Gary Y; Jochum, C Christine; Tatum, Kristin; Kobayashi, Donald Y

    2005-06-01

    ABSTRACT Lysobacter enzymogenes produces extracellular lytic enzymes capable of degrading the cell walls of fungi and oomycetes. Many of these enzymes, including beta-1,3-glucanases, are thought to contribute to the biological control activity expressed by several strains of the species. L. enzymogenes strain C3 produces multiple extracellular beta-1,3-glucanases encoded by the gluA, gluB, and gluC genes. Analysis of the genes indicates they are homologous to previously characterized genes in the related strain N4-7, each sharing >95% amino acid sequence identity to their respective counterparts. The gluA and gluC gene products encode enzymes belonging to family 16 glycosyl hydrolases, whereas gluB encodes an enzyme belonging to family 64. Mutational analysis indicated that the three genes accounted for the total beta-1,3-glucanase activity detected in culture. Strain G123, mutated in all three glucanase genes, was reduced in its ability to grow in a minimal medium containing laminarin as a sole carbon source. Although strain G123 was not affected in antimicrobial activity toward Bipolaris sorokiniana or Pythium ultimum var. ultimum using in vitro assays, it was significantly reduced in biological control activity against Bipolaris leaf spot of tall fescue and Pythium damping-off of sugar beet. These results provide direct supportive evidence for the role of beta-1,3-glucanases in biocontrol activity of L. enzymogenes strain C3.

  8. ISR meets SAR outside: additive action of the endophyte Bacillus pumilus INR7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper.

    Science.gov (United States)

    Yi, Hwe-Su; Yang, Jung Wook; Ryu, Choong-Min

    2013-01-01

    Induced resistance has been recognized as an attractive tool for plant disease management in modern agriculture. During the last two decades, studies on chemically- and biologically elicited induced resistance have revealed previously unknown features of the plant defense response including defense priming. As a biological trigger for induced resistance, plant growth-promoting rhizobacteria (PGPR) are a group of root-associated bacteria that can reduce plant disease severity and incidence, and augment plant growth and yield under greenhouse and field conditions. We evaluated the potential of an endophytic PGPR, Bacillus pumilus INR7, to induce systemic resistance against bacterial spot caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Trials in the greenhouse showed significantly less symptom development in pepper plants inoculated with strain INR7 compared to a water treatment. Furthermore, a single dipping treatment with INR7 before transplantation of pepper plants into the field elicited an induced systemic resistance response against bacterial spot caused by artificially infiltration of X. axonopodis pv. vesicatoria and even against naturally occurring bacterial spot disease. We identified an additive effect on induced resistance after administration of a combination treatment composed of strain INR7 with a chemical inducer, benzothiadiazole (BTH) in the field. The combination treatment stimulated expression of pepper defense marker genes CaPR1, CaTin1, and CaPR4 to a greater extent than did treatment with either agent alone. Similar experiments conducted with tobacco revealed no additive effects under field conditions. Interestingly, co-application of plants with INR7 lifted the growth repressing effect of BTH. Application of BTH onto pepper and tobacco did not affect rhizosphere colonization but supported a higher population density inside plant roots when compared to water-treated control plants. Our results indicate that PGPR can be used in

  9. Avaliação de cultivares de mandioca, para consumo in natura, quanto à resistência à mancha parda da folha Evaluation of cassava cultivars for resistance to brown leaf spot

    Directory of Open Access Journals (Sweden)

    Ronaldo P. Santos

    2004-06-01

    Full Text Available Visando confirmar o agente etiológico da 'mancha-parda' e avaliar diferentes cultivares de mandioca quanto à resistência a doença e às características agronômicas e nutricionais no estado do Rio de Janeiro, realizaram-se dois ensaios em condições de campo, na UFRRJ. No primeiro, de fevereiro de 1997 a junho de 1998, avaliaram-se seis cultivares (Amarelinha, Marcos OP, IAC-264, Baiana, Mantiqueira e Sonora. No segundo, de janeiro a agosto de 1999, avaliaram-se as mesmas cultivares mais a 'Saracura' e Rosada de SC. Em ambos ensaios utilizou-se o delineamento de blocos ao acaso com três repetições. A intensidade de doença, originada a partir de infecção natural, foi quantificada a cada sete e 15 dias, e por ocasião da colheita, quando se estimaram a severidade e a incidência de folhas lesionadas, taxa de desfolha e número de folhas lesionadas. Com os dados de severidade e de incidência, construíram-se curvas e calcularam-se os valores da área abaixo da curva de progresso da doença (AACPD, para as estimativas da severidade da doença e da incidência de folhas infectadas, respectivamente. Houve diferença entre as cultivares quanto à resistência à mancha parda da folha, causada por Cercosporidium henningsii. A 'Amarelinha' foi a mais suscetível e 'Baiana' e 'Sonora' as mais resistentes. Não houve, em geral, diferença significativa entre as cultivares quanto à produtividade e características das raízes, com destaque porém, para a cultivar Amarelinha que apresentou raízes mais uniformes e com maior peso médio. Houve correlação negativa e significativa entre a severidade da doença, expressa pelos valores da AACPD e número e peso das raízes.Two field experiments were conducted to confirm the etiological agent of the cassava 'brown leaf spot', to study the progress of the disease and to evaluate resistance, agronomic and nutritional traits of different cassava cultivars. The experiments were performed in Rio de

  10. Diversity of bacteriophages infecting Xanthomonas oryzae pv. oryzae in paddy fields and its potential to control bacterial leaf blight of rice.

    Science.gov (United States)

    Chae, Jong-Chan; Hung, Nguyen Bao; Yu, Sang-Mi; Lee, Ha Kyung; Lee, Yong Hoon

    2014-06-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

  11. 防治叶菜病虫害型生物菌肥生产技术%Production Technology of Biological Bacterial Fertilizer for Prevention and Cure of Plant Diseases and Insect Pests of Leaf Vegetables

    Institute of Scientific and Technical Information of China (English)

    万德印; 王刚; 郑曙光

    2015-01-01

    针对农业生产中大量使用农药、化肥所导致的食品安全和环境污染问题,开发了防治叶菜病虫害型生物菌肥生产工艺,并介绍了菌种选择及生产技术指标等。防治叶菜病虫害型生物菌肥是在传统的叶菜专用菌肥中添加枯草芽孢杆菌和苏云金芽孢杆菌,不仅可有效防治叶菜病虫害,还利于培肥地力、提高叶菜产量和品质。%In connection with problems of food safety and environmental pollution caused by pesticide and fertilizer widely used in agriculture production,the production technology of biological bacterial fertilizer for prevention and cure of plant diseases and insect pests of leaf vegetables is researched and developed,and the strain selection and production technical indexes are introduced. The biological bacterial fertilizer for prevention and cure of plant diseases and insect pests of leaf vegetables is produced by adding bacillus subtilis and bacillus thuringlensis to traditional special bacterial fertilizer for leaf vegetables,it can not only effectively prevent and cure plant diseases and insect pests of leaf vegetables,but also benefit raising soil fertility,promoting yield and quality of leaf vegetables.

  12. Liver spots

    Science.gov (United States)

    Liver spots are changes in skin color that occur in older skin. The coloring may be due to aging, exposure to the sun or other sources of ultraviolet light, or causes that are not known. Liver spots are very common after age 40. They occur ...

  13. Ação do biofertilizante Agrobio sobre a mancha-bacteriana e desenvolvimento de mudas de pimentão Effect of the Agrobio biofertilizer on the bacterial spot and the development of bell pepper transplants

    Directory of Open Access Journals (Sweden)

    Cláudia S.R. Deleito

    2005-03-01

    beneficial effect of Agrobio on bell pepper (Capsicum annuum L. transplants under greenhouse conditions. Two cultivars, 'Cascadura Ikeda' and 'Cascadura Itaipu' were used. Four Agrobio treatments, all diluted 5% (v/v in distilled water were used. They consisted of: (a raw; (b autoclaved (120ºC/20 min; (c filtered in millipore (0,22 µ diameter and (d the fraction retained on the millipore. They were applied as foliage sprays or directly on the substrate. As control treatments, oxytetracicline + streptomycin sulphate (0.8 g L-1, copper oxichloride (2.4 g L-1 and water were used. Raw of filtered Agrobio, as a foliage spray, resulted in better control of the disease and higher growth of the transplants, compared to autoclaved and fraction retained of the Agrobio and substrate sprays. All Agrobio treatments resulted in a less satisfactory disease control when compared to the commercial products, copper oxichloride and oxitetracicline + streptomycin sulphate, but more, effective than water. Agrobio stimulated the vegetative growth of the transplants, reduced the incidence of bacterial spot, increased the leaf area and promoted a better retention of infected leaves and the Bacillus spp. population.

  14. The efficacy of Carica papaya leaf extract on some bacterial and a fungal strain by well diffusion method

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    C. Baskaran

    2012-10-01

    Full Text Available Objective: To investigate the antimicrobial activity and phytochemical screening Ethanol, methanol, Ethyl acetate, acetone, chloroform, Petroleum ether, hexane, hot water, and extracts of Carica papaya. Methods: The aim of the present study was to evaluate the qualitative analysis of phytochemicals and antimicrobial activity of various solvent extracts of Carica papaya. The antimicrobial activities of different solvent extracts of Carica papaya were tested against the Gram-positive and Gram-negative bacterial strains and fungus by observing the zone of inhibition. The Gram-positive bacteria used in the test were Staphylococcus aureus, Bacillus cereus and Micrococcus luteus, and the Gram-negative bacteria were Escherichia coli, and Klebsiella pneumoniae, fungus like Aspergillus niger, Aspergillus flavus, Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Candida kefyr. Results: It was observed that ethanol, methanol, ethyl acetate, aceton, chloroform, petroleum ether, hexane and aquas extracts showed activity against bacteria and fungus. The chloroform extract of Carica papaya showed more activity against Micrococcus luteus, zone of diameter 15.17暲0.29mm and acetone extract of Carica papaya showed more activity against Candida albicans, zone of diameter 11.23暲0.25mm compared to other solvent extracts. Conclusions: In this study chloroform extract in bacteria and acetone extract in fungus showed a varying degree of inhibition to the growth of tested organism, than Ethanol, methanol, Ethyl acetate, Petroleum ether, hexane and hot water extracts. The results confirmed the presence of antibacterial and antifungal activity of Carica papaya extract against various human pathogenic bacteria. Presences of phytochemical and antimicrobial activity are confirmed.

  15. Identification and biological characteristics of pathogen of oat brown leaf spot in Tibetan%西藏秋播燕麦苗期褐斑病病原鉴定及生物学特性研究

    Institute of Scientific and Technical Information of China (English)

    何苏琴; 荆卓琼; 丁文娇; 赵桂琴; 金涛

    2011-01-01

    通过病原菌的分离、回接及病原菌形态学鉴定,将西藏秋播燕麦褐斑病的病原鉴定为麦根腐平脐蠕孢(Bipolaris sorokiniana)。病菌菌丝在5~35℃均可生长,最适生长温度30℃;在10~30℃均可产孢,20℃时的产孢量最大。培养温度不同,孢子大小亦不同,20℃时孢子最大;15℃时孢子隔膜数最多。分生孢子在10%的燕麦叶汁中,5~35℃均可萌发,15~35℃5h的萌发率≥90%;20~30℃5h的萌发率〉95%。对燕麦、玉米、高粱、青稞、小麦、豌豆具有较强的致病性。%Pathogen(strain YMZD-2),isolated from brown leaf spot of autumn sowing oat in Tibetan Shannan Region,was identificated based on Koch's rule and morphology and and its Biological Characteristics was tested as well.The results showed that the pathogen(strain YMZD-2) belongs to Bipolaris sorokiniana.And mycelial growing temperature ranged from 5 ℃ to 35 ℃,(optimum 30 ℃).The highest condia yield was at 20 ℃.The morphology of conidia was variable with cultural temperatures,the biggest conidia was at 20 ℃,the most distoseptate numbers were at 15 ℃.Conidia germinated at 5~35 ℃,germination percentage higher than 90% at 15~35 ℃,and 95% at 20~30 ℃which were both under treatments in 5 hours in 5 hours in 10% oat leaf juice.The pathogen showed there were aggressive virulence to oat,corn,sorghum,hulless barley,wheat and pea under artificial inoculation condition.

  16. 454-Pyrosequencing survey of microbiota in adult Spotted Wing Drosophila (SWD) corroborates a core microbiome and additional symbiotic and entomopathogenic bacterial associates

    Science.gov (United States)

    Complete surveys of insect endosymbionts including species of economic importance have until recently been hampered by a lack of high-throughput genetic assays. We used 454-pyrosequencing of the 16S rRNA gene amplicon of adult spotted wing Drosophila (SWD) Drosophila suzukii (Matsumura) from souther...

  17. OCCURRENCE OF LEAF SPOTS CAUSED BY FUNGI AND A BACTERIUM ON COTTON CULTIVARS OCORRÊNCIA DE MANCHAS FOLIARES CAUSADAS POR FUNGOS E BACTÉRIA EM CULTIVARES DE ALGODOEIRO

    Directory of Open Access Journals (Sweden)

    Miguel Ferreira Soria

    2008-11-01

    Full Text Available

    The cotton leaf spot diseases caused by fungi and bacteria are a growing problem, leading to an increasing use of fungicides. During the 2000/2001 and 2001/2002 growing seasons, field experiments were carried out in a randomized block design, with five replications, aiming to evaluate the behavior of the cotton cultivars Ita-90, CD-401, CD-402, CD-403, CD-404, Fibermax 986, DeltaOpal, and Facual, as related to leaf spot diseases caused by Stemphylium spp., Alternaria spp., Ramularia areola, and the bacterium Xanthomonas axonopodis pv. malvacearum. The cotton cultivars Ita-90 and Facual were the less susceptible to the Stemphylium/Alternaria complex and R. areola. However, Ita-90 was more susceptible to X. axonopodis pv. Malvacearum. The cultivars with the least incidence of X. axonopodis were CD-403, Fibermax 986, and DeltaOpal. The cotton cultivar Facual presented the lowest yield, while the remaining cultivars showed similar yields.

    KEY-WORDS: Xanthomonas axonopodis pv. Malvacearum; Stemphylium spp; Alternaria spp; Ramularia areola.

    As manchas foliares causadas por fungos e bactérias no algodoeiro são um problema cada vez mais grave, levando à utilização, cada vez maior, de fungicidas para controlá-las. Nas safras de 2000/2001 e 2001/2002, foram realizados experimentos m campo, em delineamento de blocos ao acaso, com cinco epetições, objetivando avaliar o comportamento das

  18. Characterization of rust, early and late leaf spot resistance in wild and cultivated peanut germplasm Caracterização da resistência à ferrugem, mancha preta e mancha castanha em germoplasma silvestre e cultivado de amendoim

    Directory of Open Access Journals (Sweden)

    Alessandra Pereira Fávero

    2009-02-01

    Full Text Available Groundnut (Arachis hypogaea has an AB genome and is one of the most important oil crops in the world. The main constraints of crop management in Brazil are fungal diseases. Several species of the genus Arachis are resistant to pests and diseases. The objective of our experiments was to identify wild species belonging to the taxonomic section Arachis with either A or B (or " non-A" genomes that are resistant to early leaf spot (Cercospora arachidicola, late leaf spot (Cercosporidium personatum and rust (Puccinia arachidis. For the identification of genotypes resistant to fungal diseases, bioassays with detached leaves were done in laboratory conditions, with artificial inoculation, a controlled temperature of 25ºC and a photoperiod of 10 h light/14 h dark, for 20-42 days, depending on the fungi species. Most of the accessions of wild species were more resistant than accessions of A. hypogaea for one, two or all three fungi species studied. Arachis monticola, considered to be a possible tetraploid ancestor or a derivative of A. hypogaea, was also more susceptible to Cercosporidium personatum and Puccinia arachidis, as compared to most of the wild species. Therefore, wild germplasm accessions of both genome types are available to be used for the introgression of resistance genes against three fungal diseases of peanut.O amendoim (Arachis hypogaea possui genoma AB e é uma das mais importantes culturas oleaginosas em todo o mundo. Os principais problemas da cultura no Brasil são as doenças fúngicas. Várias espécies do gênero Arachis são resistentes a pragas e doenças. Este trabalho visou a identificar espécies silvestres pertencentes à seção Arachis associadas aos genomas A ou B (ou " não-A" do amendoim que são resistentes à mancha castanha (Cercospora arachidicola, mancha preta (Cercosporidium personatum e ferrugem (Puccinia arachidis. Para a identificação de genótipos resistentes a doenças fúngicas, bioensaios utilizando

  19. Epidemic Law of Cassava Brown Leaf Spot Caused by Passalora henningsii in the Red River Basin of Yunnan Province%云南红河流域木薯褐斑病流行规律初步研究

    Institute of Scientific and Technical Information of China (English)

    张光勇; 黄绍中; 陈伟强; 孙寅虎; 张建春; 邓成菊; 李芹; 刘学敏; 杨绍琼; 王晓燕

    2016-01-01

    采用系统观察方法对红河流域木薯主产区木薯褐斑病发生和流行规律进行研究,结果表明:病害在木薯生长前期5月份开始发病,生长中、后期的7月份后病情呈明显上升,9、10月份达到最高峰,危害率达100%,病情指数20.50~30.77;下游区域的病情>中游>上游,病情的周年消长和区域性差异主要是降雨量和湿度的影响;高海拔区域(350~400 m)病情高于低海拔区域(250~300 m),这与高海拔区域气温相对偏低有关。%The occurrence and epidemic law of cassava Brown Leaf Spot were studied through systematic observation. The re-sults indicated that this disease appeared in the early stage of growth in May, and significantly become more seriously in the middle and late growth stage in July, finally to the peak in September and October, with 100% of infection. The disease index ranged in 20.50 to 30.77. It was found that the disease was getting worse from upstream, the middle segment to the down-stream of this basin. The rainfall and humidity have greatly effect on the dynamics of the disease in a year. Why there are more serious disease at high altitude of 350 to 400 m than that of at altitude of 250 to 300 m, just because of the low temperature.

  20. Spotted inflation

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Tomohiro, E-mail: matsuda@sit.ac.jp [Laboratory of Physics, Saitama Institute of Technology, Fusaiji, Okabe-machi, Saitama 369-0293 (Japan)

    2010-11-01

    We describe new scenarios for generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ''spot'', which arises from interactions associated with an enhanced symmetric point (ESP) on the trajectory. Our first example uses the spot to induce a gap in the field equation. We observe that the gap in the field equation may cause generation of curvature perturbation if it does not appear simultaneous in space. The mechanism is similar to the scenario of inhomogeneous phase transition. Then we observe that the spot interactions may initiate warm inflation in the cold Universe. Creation of cosmological perturbation is discussed in relation to the inflaton dynamics and the modulation associated with the spot interactions.

  1. Controle químico da mancha-bacteriana do tomate para processamento industrial em campo Field chemical control of bacterial spot on tomato for industrial processing

    Directory of Open Access Journals (Sweden)

    Abadia dos R Nascimento

    2013-03-01

    cloretos de benzalcônio. ASM e famoxadona + mancozebe foram os que promoveram uma relação benefício/custo superior a 1.In order to evaluate chemical control of bacterial spot on tomato for industrial processing, two field trials were carried out at the Unilever Bestfoods experimental station, in Goiânia, Goias state, Brazil. The first trial was in a randomized complete block design, with 15 treatments and three replications, using the hybrid Heinz 9992 inoculated with Xanthomonas perforans. The second trial was in a split-plot randomized complete block design with chemical foliar applications (10 treatments and hybrids (Hypeel 108 and U2006 as factors. Plants were inoculated with X. perforans and X. gardneri. In both trials the chemicals, in different number of applications and combinations, were: acibenzolar-S-methyl (ASM; famoxadone + mancozeb; metiram + pyraclostrobin; phosphite PK; benzalkonium chlorides; cuprous oxide, and copper hydroxide (SC, WP and WG. For both trials, disease severity on leaves, number of fruits with symptoms and yield were evaluated. In the second one, sunscald was also evaluated. For the first trial, significant severity differences (p>0.05 among treatments were observed only in the first two evaluations, but none of them differed from the water check control. In the second trial, significant differences were detected only in foliar severity in first evaluation for hybrids. For number of fruits with symptoms and sunscald, besides hybrids, interaction among factors was also significant. 'U2006' was more resistant than 'Hypeel 108', which also had highest sunscald values, but concerning fruits with symptoms, the opposite was observed. The two factors were significant for yield data, 'U2006' yielded better than 'Hypeel 108'. Despite none of the treatments have differed in yield from the water control, famoxadone + mancozeb, which resulted in the highest yield, differed from copper hydroxide, ASM - famoxadone + mancozeb, and benzalkonium

  2. The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces.

    Directory of Open Access Journals (Sweden)

    Nina Bjørk Arnfinnsdottir

    Full Text Available In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG. On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis.

  3. The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces

    Science.gov (United States)

    Arnfinnsdottir, Nina Bjørk; Ottesen, Vegar; Lale, Rahmi; Sletmoen, Marit

    2015-01-01

    In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD) on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG). On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis. PMID:26039378

  4. SPOT Program

    Science.gov (United States)

    Smith, Jason T.; Welsh, Sam J.; Farinetti, Antonio L.; Wegner, Tim; Blakeslee, James; Deboeck, Toni F.; Dyer, Daniel; Corley, Bryan M.; Ollivierre, Jarmaine; Kramer, Leonard; Zimmerman, Patrick L.; Khatri, Reshma

    2010-01-01

    A Spacecraft Position Optimal Tracking (SPOT) program was developed to process Global Positioning System (GPS) data, sent via telemetry from a spacecraft, to generate accurate navigation estimates of the vehicle position and velocity (state vector) using a Kalman filter. This program uses the GPS onboard receiver measurements to sequentially calculate the vehicle state vectors and provide this information to ground flight controllers. It is the first real-time ground-based shuttle navigation application using onboard sensors. The program is compact, portable, self-contained, and can run on a variety of UNIX or Linux computers. The program has a modular objec-toriented design that supports application-specific plugins such as data corruption remediation pre-processing and remote graphics display. The Kalman filter is extensible to additional sensor types or force models. The Kalman filter design is also strong against data dropouts because it uses physical models from state and covariance propagation in the absence of data. The design of this program separates the functionalities of SPOT into six different executable processes. This allows for the individual processes to be connected in an a la carte manner, making the feature set and executable complexity of SPOT adaptable to the needs of the user. Also, these processes need not be executed on the same workstation. This allows for communications between SPOT processes executing on the same Local Area Network (LAN). Thus, SPOT can be executed in a distributed sense with the capability for a team of flight controllers to efficiently share the same trajectory information currently being computed by the program. SPOT is used in the Mission Control Center (MCC) for Space Shuttle Program (SSP) and International Space Station Program (ISSP) operations, and can also be used as a post -flight analysis tool. It is primarily used for situational awareness, and for contingency situations.

  5. Identification of the Pathogen from Cassava Brown Leaf Spot and Its Biological Characteristics%木薯褐斑病病原鉴定及其生物学特性研究

    Institute of Scientific and Technical Information of China (English)

    裴月令; 时涛; 李超萍; 蔡吉苗; 黄贵修

    2013-01-01

    褐斑病是中国木薯生产中最为严重的叶部真菌性病害.采用多种分离方法,经致病性评价后获得该病的病原菌,形态观察和ITS序列分析结果表明其为亨宁氏钉孢(Passalora henningsii).比较光照、菌丝打断、紫外线和菌丝打断-紫外等方法的诱导产孢效果,结果表明:只有菌丝打断-紫外诱导法能够产生大量分生孢子,CME(麦芽木薯叶)培养基、28℃、pH6.0~7.0、紫外线连续诱导、25 mL/皿、14~21 d为产孢最适条件.对菌株CPHHN02的生物学特性研究表明,CA培养基、26~28℃、pH6.0、连续黑暗、碳氮源分别为D-葡萄糖、D-甘露醇、D-乳糖和胰蛋白胨为菌株最适培养条件.大型分生孢子的最适萌发温度为26℃,致死温度为60℃10 min.%Brown Leaf Spot is the most serious leaf fungous disease in the cassava plantations of China.In our research,several separation and inoculation methods were applied,pathogenicity test was finished and the pathogen was isolated,morphlogical identification and ITS sequence analysis indicated the pathogen was Passalora henningsii.Four methods(light,hyphae-breaking,UV and hyphae broken-UV)were compared for their inducing capability in producing conidia from P.henningsii.The results showed large number of conidia could obtain by hyphae broken-UV method,and the best condition was Malt-cassava leaves medium,28 ℃,pH 6.0~7.0,continuous UV induction,25 mL/plate,14~21 d.The biological characteristics study of strain CPHHN02 showed CA medium,26~28 ℃,pH 6.0,continuous dark,D-glucose,D-mannitol,D-lactose and tryptone were the best culture condition.The optimal temperature for macroconidia germination was 26 ℃ and the lethal temperature was 60 ℃ for 10 min.

  6. Research methodology for maize gray leaf spot:Ⅰ.sporulation of Cercospora zeae-maydis%玉米灰斑病研究方法:Ⅰ.玉米灰斑病菌孢子的培养

    Institute of Scientific and Technical Information of China (English)

    赵正龙; 吴兴兴; 毛自朝; 何月秋

    2011-01-01

    为了明确玉米灰斑病菌的产孢条件,将玉米灰斑病菌接种到马铃薯蔗糖(PSA),燕麦番茄碳酸钙(OTCA)、玉米叶粉碳酸钙(MLPCA)、燕麦粉(OA)、粗面粉(CWPA)等5种培养基上,于25℃下培养,测定该菌生长速度、产孢时间和产孢量.结果表明,菌丝在上述培养基上生长速度均较慢,每天平均生长0.33 nun左右,其中以在OA和PSA上生长速度相对较快.基于上述结果,构建了玉米灰斑病菌孢子培养的二级分段培养法,即将菌丝块接种于加有10~15粒直径为5 mm玻璃珠的马铃薯蔗糖(PS)液体培养基三角瓶里,在25℃,180 r/min条件下振荡培养15 d,形成菌丝悬液,再取菌丝悬浮液涂布在MLPCA培养基上,避光培养13 d左右,可获得大童供接种的分生孢子.长期光照促进菌丝生长,不利于孢子的形成,而长期黑暗不利于菌丝生长,但有利于孢子的形成.%The pathogen of maize gray leaf spot, Cercospora zeae-maydis, was inoculated on potato sucrose agar (PSA), oat tomato plus CaCO3 agar(OTCA), maize leaf powder plus CaCO3 agar(MLPCA), oatmeal agar(OA) and crude wheat powder agar (CWPA), and incubated at 25 ℃ for measuring the mycelial growth, sporulation time and number. The results showed that the mycelia grew very slow on the media, with an average of 0.33 mm per day. They grew fastest on OA and PSA, slower on CWPA and most slowly on MLPCA. Based on the results,a sporulation method was set up, namely two-step culturing method. The mycelia were inoculated into flask with PS and 10-15 glass balls of 5mm diameter, and shaken at 25 ℃ and 180 r/min for 15 days, to culture the mycelial fragment suspension. Then the suspension was smeared on MLPCA medium and incubated for about 13 days at 25 ℃ without light. By this way, a large number of spores could be produced for inoculation. Long illumination promoted the mycelial growth, but on the contrary, long darkness was conducive to sporulation.

  7. 油棕叶斑病的病原鉴定及其生物学特性%Identification and Biological Characteristics of Pathogen of Leaf Spot in Oil Palm, (Elaeis guineensis Jacq)

    Institute of Scientific and Technical Information of China (English)

    牛晓庆; 唐庆华; 余凤玉; 朱辉; 宋薇薇; 雷新涛

    2011-01-01

    对油棕发生的一种严重叶部病害进行研究,对该病病原进行了分离和鉴定,经ITS序列分析确定该病病原为半知菌亚门拟茎点霉属真菌.生物学特性研究结果表明:该茵分生孢子呈椭圆形或球形,浅褐色至深褐色;马铃薯葡萄糖琼脂培养基(PDA)最适合该茵生长,其次是胡萝卜琼脂培养基(CDA)和燕麦琼脂培养基(OMA);在10 ~30℃范围内均可生长,最适生长温度为25℃;最适pH值为7.0;以葡萄糖为碳源,以蛋白胨为氮源最适合茵丝生长,该病原茵的致死温度是50℃.%A pathogen causing the leaf spot disease of Elaeis guineensis Jacq was isolated and identified by ITS sequence analysis, and its biological characteristics were studied in this paper. The results showed that the pathogen was identified as Phomopsis sp. In Deuteromycotina, its conidiophore was oval or round in shape, and light brown or deep brown in color. Potato dextrose agar medium (PDA) was the optimum medium for its mycelial growth, followed by carrot agar medium (CDA) and oat agar medium (OMA). The proper temperature for its mycelial growth ranged from 10 °C to 30 °C , but the optimum temperature was 25 t. The suitable pH - value was 7.0. For the mycelial growth of this pathogen, the optimum carbon source and nitrogen source were glucose and tryptone respectively, and the lethal temperature to Phomopsis sp. Was 50 °C.

  8. Occurrence and Distribution of Papaya ring spot virus and Papaya leaf-distortion mosaic virus in Hainan Province%海南番木瓜PRSV和PLDMV病毒发生情况及分子鉴定

    Institute of Scientific and Technical Information of China (English)

    张雨良; 黄启星; 郭安平; 曾会才; 赵辉; 孔华; 刘志昕

    2013-01-01

    对海南昌江、乐东、澄迈、文昌和三亚5个主要番木瓜产区的病毒病发生情况进行调查.对76份番木瓜疑似病毒样品进行检测,检测结果表明海南番木瓜病毒病主要有2种:由番木瓜环斑病毒(Papaya ring spot virus,PRSV)引起的番木瓜环斑病毒病和由番木瓜畸形花叶病毒(Papaya leaf-distortion mosaic virus,PLDMV)引起的番木瓜畸形花叶病毒病.其中,番木瓜环斑病毒病最为常见,检出率达77.63%,是影响海南地区番木瓜产业健康发展的主要病毒病:畸形花叶病毒病发生率很低,仅检出2例番木瓜畸形花叶病毒病样品.以PRSV病毒基因组P1和Hc-Pro作为靶标基因进行分子克隆、测序,结果表明海南地区PRSV病毒可明显分为2个株系:HNPRSV-1株系和HN-PRSV-2株系.此外,基于CP基因的系统进化树分析结果表明在海南新发现的PLDMV病毒可能源于台湾和日本.本研究可为开展番木瓜花叶病的防控和创制抗花叶病毒番木瓜新种质提供数据参考.

  9. CONTROL OF ANGULAR LEAF SPOT BY USING PROTECTIVE MIXTURES IN IRRIGATED COMMON BEAN UNDER ORGANIC CROPPING SYSTEM CONTROLE DE MANCHA-ANGULAR UTILIZANDO-SE CALDAS FERTIPROTETORAS EM CULTIVO ORGÂNICO DE FEIJOEIRO IRRIGADO

    Directory of Open Access Journals (Sweden)

    Charles Martins de Oliveira

    2010-10-01

    Full Text Available

    A field experiment was carried out with the Pérola and BRS Valente cultivars, aiming to evaluate the efficiency of protective mixtures, in two spraying periods, for controlling angular leaf spot caused by Phaeoisariopsis griseola in common bean, under organic cropping system, in the dry season and under irrigation. A randomized complete block design, in a 2x4 factorial scheme, with four replications, was used, in which the first factor was the spraying intervals (15 and 30 days, and the second the protective mixtures (bordeaux, lime sulfur, and a mixture with silicate Rocksil® and control without any mixture. To the Pérola cultivar, the bordeaux mixture provided an increase of 17,7% in grain yield, when compared to the non-sprayed control, reducing significantly the angular leaf spot severity, achieving a control efficiency of 75%, and propitiating a profit of R$ 386.40 ha-1, when applied at each 15 days. To the BRS Valente cultivar, the bordeaux mixture and lime sulfur provided an increase of 25% and 21,8% in grain yield, in comparison to the non-sprayed control, achieving a control efficiency of 62% and a profit of R$ 573.15 ha-1 and R$ 464.10 ha-1, respectively, when applied at each 15 days.

    KEY-WORDS: Phaeoisariopsis griseola; Phaseolus vulgaris; organic agriculture; bordeaux mixture; lime sulfur.

    Bacterial diversity shift determined by different diets in the gut of the spotted wing fly Drosophila suzukii is primarily reflected on acetic acid bacteria

    KAUST Repository

    Vacchini, Violetta

    2016-11-25

    The pivotal role of diet in shaping gut microbiota has been evaluated in different animal models, including insects. Drosophila flies harbour an inconstant microbiota among which acetic acid bacteria (AAB) are important components. Here, we investigated the bacterial and AAB components of the invasive pest Drosophila suzukii microbiota, by studying the same insect population separately grown on fruit-based or non-fruit artificial diet. AAB were highly prevalent in the gut under both diets (90 and 92% infection rates with fruits and artificial diet, respectively). Fluorescent in situ hybridization and recolonization experiments with green fluorescent protein (Gfp)-labelled strains showed AAB capability to massively colonize insect gut. High-throughput sequencing on 16S rRNA gene indicated that the bacterial microbiota of guts fed with the two diets clustered separately. By excluding AAB-related OTUs from the analysis, insect bacterial communities did not cluster separately according to the diet, suggesting that diet-based diversification of the community is primarily reflected on the AAB component of the community. Diet influenced also AAB alpha-diversity, with separate OTU distributions based on diets. High prevalence, localization and massive recolonization, together with AAB clustering behaviour in relation to diet, suggest an AAB role in the D. suzukii gut response to diet modification. This article is protected by copyright. All rights reserved.

  10. Bacterial diversity shift determined by different diets in the gut of the spotted wing fly Drosophila suzukii is primarily reflected on acetic acid bacteria.

    Science.gov (United States)

    Vacchini, Violetta; Gonella, Elena; Crotti, Elena; Prosdocimi, Erica M; Mazzetto, Fabio; Chouaia, Bessem; Callegari, Matteo; Mapelli, Francesca; Mandrioli, Mauro; Alma, Alberto; Daffonchio, Daniele

    2017-04-01

    The pivotal role of diet in shaping gut microbiota has been evaluated in different animal models, including insects. Drosophila flies harbour an inconstant microbiota among which acetic acid bacteria (AAB) are important components. Here, we investigated the bacterial and AAB components of the invasive pest Drosophila suzukii microbiota, by studying the same insect population separately grown on fruit-based or non-fruit artificial diet. AAB were highly prevalent in the gut under both diets (90 and 92% infection rates with fruits and artificial diet respectively). Fluorescent in situ hybridization and recolonization experiments with green fluorescent protein (Gfp)-labelled strains showed AAB capability to massively colonize insect gut. High-throughput sequencing on 16S rRNA gene indicated that the bacterial microbiota of guts fed with the two diets clustered separately. By excluding AAB-related OTUs from the analysis, insect bacterial communities did not cluster separately according to the diet, suggesting that diet-based diversification of the community is primarily reflected on the AAB component of the community. Diet influenced also AAB alpha-diversity, with separate OTU distributions based on diets. High prevalence, localization and massive recolonization, together with AAB clustering behaviour in relation to diet, suggest an AAB role in the D. suzukii gut response to diet modification. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  11. TUC 550: nueva variedad de poroto negro (Phaseolus vulgaris L. con tolerancia a la mancha angular (Phaeoisariopsis griseola TUC 550: a new variety of black bean (Phaseolus vulgaris L. with tolerance to angular leaf spot (ALS

    Directory of Open Access Journals (Sweden)

    Oscar N. Vizgarra

    Full Text Available La mancha angular del poroto (Phaseolus vulgaris L., causada por el hongo Phaeoisariopsis griseola (Sacc. Ferraris, provoca pérdidas importantes en el cultivo de poroto. Este trabajo describe la obtención de una nueva variedad de poroto negro, con tolerancia a la mancha angular y óptimo rendimiento, que podría reemplazar a las actuales variedades comerciales difundidas en el Noroeste Argentino. En el año 2001, se introdujeron del Centro Internacional de Agricultura Tropical (CIAT, Colombia, 55 líneas de poroto negro, en las que se combinaban genes que les otorgaban tolerancia múltiple a las principales enfermedades, entre ellas, la mancha angular. Estas líneas fueron sembradas en parcelas de observación en las localidades de La Invernada (La Cocha, Tucumán y San Agustín (Cruz Alta, Tucumán en los años 2002 y 2003. El testigo local fue la variedad TUC 500. Se identificaron cuatro líneas con altos niveles de tolerancia, las que posteriormente fueron evaluadas en invernáculo con 10 patotipos de P. griseola, provenientes de la zona de cultivo. Como resultado de las evaluaciones, se seleccionó una línea adaptada a la región con buen comportamiento con respecto a mancha angular y buen potencial de rendimiento. Estas características fundamentaron la inscripción de TUC 550, en el año 2006, como una nueva variedad de poroto negro ante el Instituto Nacional de Semillas (INASE.The purpose of this work was to develop a bean cultivar with tolerance to angular leaf spot (ALS which would replace the susceptible bean cultivars currently used in Northwestem Argentina (NWA. In 2001, 55 lines of black beans were introduced from the International Center for Tropical Agriculture. These presented multiple genes that endowed them with tolerance to the main diseases affecting the crop. In 2002, these lines were cultivated at two sites, La Invernada (La Cocha, Tucumán and San Agustín (Cruz Alta, Tucumán, in order to compare their yields and

  12. Época de aplicação de fungicida para controle da mancha de Mycosphaerella do morangueiro Timing of fungicide application for Mycosphaerella leaf spot control on strawberry

    Directory of Open Access Journals (Sweden)

    Cleber Furlanetto

    1999-11-01

    Full Text Available Estudou-se o efeito da época do início da aplicação de fungicida na severidade da mancha de Mycosphaerella fragariae em parcelas experimentais de morango cv. IAC-Campinas. O ensaio foi conduzido em área produtora (Brazlândia, DF em blocos ao acaso com seis tratamentos (épocas de início de pulverização e quatro repetições. Foram efetuadas aplicações quinzenais com o p.a. prochloraz (450 g i.a/litro na dosagem de 100 ml/100 litros de água, e testadas as épocas de início de aplicação: Plantio (pulverização por ocasião do plantio das mudas, com um total de dez aplicações; Flor1 (após a primeira florada, oito aplicações; Flor2 (após a segunda florada, seis aplicações; Flor3 (após a terceira florada, quatro aplicações; Flor4 (após a quarta florada, duas aplicações e Test (testemunha pulverizada com água desde o transplantio. As seguintes variáveis foram avaliadas: produção total acumulada; severidade de doença; número de folhas mortas e sadias; número de hastes lesionadas e sadias. Os resultados indicaram que os tratamentos Plantio e Flor1 foram superiores aos demais em todos os critérios (Duncan, 5%. O tratamento Flor2 apresentou controle intermediário de doença. Os demais tratamentos não apresentaram diferenças estatísticas significativas entre si.The effect of timing of first fungicide application on the severity of Mycosphaerella leaf spot (Mycosphaerella fragariae on strawberry cv. IAC-Campinas was studied in field plots located in Brazlândia-DF, Brazil. The experiment was conducted as a randomized complete block design with six treatments (times of first fungicide delivery and four replicates. The fungicide (prochloraz - 450 g a.i./L was delivered at a dosage of 100 ml/100 L of water, on a 15-day schedule. The following periods for first application were tested: "Plant": at transplant stage; with a total of ten fungicide applications; "Flor1": at first flowering stage, total of eight applications

  13. ITS-rDNA phylogeny of Colletotrichum spp. causal agent of apple Glomerella leaf spot Filogenia por ITS-rDNA de Colletotrichum spp., agente causal da mancha foliar da Gala em macieira

    Directory of Open Access Journals (Sweden)

    Diorvania Ribeiro Giaretta

    2010-04-01

    Full Text Available Several diseases have affected apple production, among them there is Glomerella leaf spot (GLS caused by Colletotrichum spp. The first report of this disease in apple was in plants nearby citrus orchards in São Paulo State, Brazil. The origin of this disease is still not clear, and studies based on the molecular phylogeny could relate the organisms evolutionarily and characterize possible mechanisms of divergent evolution. The amplification of 5.8S-ITS (Internal Transcribed Spacer of rDNA of 51 pathogenic Colletotrichum spp. isolates from apples, pineapple guava and citrus produced one fragment of approximately 600 bases pairs (bp for all the isolates analyzed. The amplified fragments were cleaved with restriction enzymes, and fragments from 90 to 500bp were obtained. The sequencing of this region allowed the generation of a phylogenetic tree, regardless of their hosts, and 5 isolated groups were obtained. From the "in silico" comparison, it was possible to verify a variation from 93 to 100% of similarity between the sequences studied and the Genbank data base. The causal agent of GLS is nearly related (clustered to isolates of pineapple guava and to the citrus isolates used as control.A produção de maçã vem sendo comprometida pela ocorrência de muitas doenças, entre as quais se destaca a Mancha Foliar de Glomerella (MFG, causada por Colletotrichum spp. O primeiro relato dessa doença em maçã foi registrado em plantas próximas a pomares de citrus no Estado de São Paulo, Brasil. A origem da MFG ainda não está bem clara, e estudos baseados na filogenia permitirão relacionar o organismo evolutivamente, possibilitando caracterizar possíveis mecanismos divergentes de evolução. A amplificação da região 5.8S-ITS (espaçador interno transcrito do rDNA de 51 isolados de Colletotrichum patogênicos em de maçã, goiabeira serrana e citrus produziu um fragmento de aproximadamente 600 pares de bases (pb para todos os isolados analisados

  14. Intensity of angular leaf spot and anthracnose on pods of common beans cultivated in three cropping systems Intensidade da mancha-angular e da antracnose em vagens de feijão em três sistemas de cultivo

    Directory of Open Access Journals (Sweden)

    Rogério Faria Vieira

    2009-01-01

    Full Text Available With the purpose to evaluate the intensity of angular leaf spot (ALS and anthracnose (ANT on pods, nine genotypes of common bean were planted in three cropping systems: monocrop (MC, monocrop grown on trellises (MCT, and intercrop with maize (ICM. In MC, beans were planted 0.5 m apart. Trelisses were set up with 1.8 m high bamboos and beans were sown 0.65 m apart. In ICM, beans were planted simultaneously with maize and in its rows. This cereal was sown 1.0 m apart with four plants per meter. Each cropping system was an independent trial installed close to each other. Climbing genotypes of beans most susceptible to ALS had less diseased pods in ICM than in both MC and MCT, but the less susceptible genotypes, regardless of their growth type, as well as the susceptible bush and semiclimbing genotypes, were similarly attacked by ALS in the three systems. ANT on pods of the susceptible bean cv. Pérola was less intense in MCT than in MC, and less intense in ICM than in MCT. ANT seed transmission was 11 %, 9.1 %, and 4.4 % when seeds come from MC, MCT, and ICM, respectively.Com o objetivo de avaliar a intensidade da mancha-angular (MA e da antracnose (ANT em vagens, nove genótipos de feijão foram plantados em três sistemas de plantio: monocultivo (MC, monocultivo com tutoragem artificial (MCT e consórcio com milho (CCM. No MC, o feijão foi semeado no espaçamento entre fileiras de 0,50 m. Para o MCT, utilizaram-se varas de bambu formando "Vs" invertidos com 1,8 m de altura, nos quais foi mantido o espaçamento entre fileiras de 0,65 m na base. No CCM, o feijão foi plantado simultaneamente ao milho e em suas fileiras. Esse cereal foi semeado no espaçamento de 1,0 m, com quatro plantas por metro. Cada sistema de cultivo foi um ensaio independente, todos instalados na mesma área. Os genótipos trepadores mais suscetíveis à MA apresentaram menos vagens doentes no CCM que no MC e MCT, mas os genótipos menos atacados pela MA, independentemente

  15. Immune responses of whiteleg shrimp, Litopenaeus vannamei (Boone, 1931), to bacterially expressed dsRNA specific to VP28 gene of white spot syndrome virus.

    Science.gov (United States)

    Taju, G; Madan, N; Abdul Majeed, S; Kumar, T Raj; Thamizhvanan, S; Otta, S K; Sahul Hameed, A S

    2015-05-01

    In this study, dsRNA specific to VP28 gene of white spot syndrome virus (WSSV) of shrimp was synthesized in Escherichia coli in large scale and studied the immune response of shrimp to dsRNA-VP28. The haematological parameters such as clotting time and total haemocytes counts, and immunological parameters such as prophenoloxidase (proPO), superoxide dismutase (SOD), superoxide anion (SOA) and malondialdehyde content, as well as the mRNA expression of ten immune-related genes were examined to estimate the effect of dsRNA-VP28 on the innate immunity of Litopenaeus vannamei. The activities of proPO, SOA and SOD significantly increased in haemocyte after dsRNA-VP28 treatment, whereas MDA content did not change significantly. Among the ten immune-related genes examined, only the mRNA expression of proPO, cMnSOD, haemocyanin, crustin, BGBP, lipopolysaccharides (LPs), lectin and lysozyme in haemocytes, gill and hepatopancreas of L. vannamei, was significantly upregulated at 12 h after dsRNA-VP28 treatment, while no significant expression changes were observed in Toll receptor and tumour receptor genes. The increase of proPO and SOD activities, and SOA level and mRNA expression level of proPO, cMnSOD, haemocyanin, crustin, BGBP, LPs, lectin and lysozyme after dsRNA-VP28 stimulation indicate that these immune-related genes were involved in dsRNA-VP28-induced innate immunity in shrimp.

  16. Mongolian spots

    Directory of Open Access Journals (Sweden)

    Divya Gupta

    2013-01-01

    Full Text Available Mongolian spots (MS are birthmarks that are present at birth and their most common location is sacrococcygeal or lumbar area. Lesions may be single or multiple and usually involve < 5% total body surface area. They are macular and round, oval or irregular in shape. The color varies from blue to greenish, gray, black or a combination of any of the above. The size varies from few to more than 20 centimetres. Pigmentation is most intense at the age of one year and gradually fades thereafter. It is rarely seen after the age of 6 years. Aberrant MS over occiput, temple, mandibular area, shoulders and limbs may be confused with other dermal melanocytoses and bruises secondary to child abuse, thus necessitating documentation at birth. Although regarded as benign, recent data suggest that MS may be associated with inborn errors of metabolism and neurocristopathies. Mongolian spots usually resolve by early childhood and hence no treatment is generally needed if they are located in the sacral area. However, sometimes it may be required for extrasacral lesions for cosmesis.

  17. A study on the effect of using mangrove leaf extracts as a feed additive in the progress of bacterial infections in marine ornamental fish

    Institute of Scientific and Technical Information of China (English)

    Thangavelu Balasubramanian; Kapila Tissera

    2013-01-01

    Objective: To ascertain the feasibility of using sustainable natural resources in maintaining disease free fish in such establishments.Methods:causative bacteria were identified by morphology and biochemical techniques. The antibacterial activity and disease resistant capability of mangrove plant leaf extract were investigated against fish pathogens.Results:The infected marine ornamental fishes were collected from the hatchery condition and inhibition activity at the concentration of 220, 200, 175 and 150 µg/mL against Pseudomonas fluorescens, Pseudomonas aeruginosa, Vibrio parahaemolyticus, and Vibrio anguillarum respectively. The experimental trial reveals feeding marine ornamental fish with feed incorporated with a methanol leaf extract of Avicennia marina, increases their survival and reduces their susceptibility to infections from the isolated bacteria. Based on the in vitro assay, methanol extract of Avicennia marina was exhibited good Conclusions: The mangrove leaves have potential to control the infections caused by Pseudomonas fluorescens, Pseudomonas aeruginosa, Vibrio parahaemolyticus and Vibrio anguillarum.

  18. Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples.

    Science.gov (United States)

    Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S

    2015-12-01

    We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10(0) stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10(0)) stock and 20 μl aliquots of six dilutions (10(1)-10(6)) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10(0)-10(5) dilutions, and for colloidal suspensions and solid samples (10% w/v), 10(1)-10(6) dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae, SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

  19. Optimization of single plate-serial dilution spotting (SP-SDS with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples

    Directory of Open Access Journals (Sweden)

    Pious Thomas

    2015-12-01

    Full Text Available We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS with the prime recommendation of sample anchoring (100 stocks. For pure cultures, serial dilutions were prepared from 0.1 OD (100 stock and 20 μl aliquots of six dilutions (101–106 were applied as 10–15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 100–105 dilutions, and for colloidal suspensions and solid samples (10% w/v, 101–106 dilutions were used. Following incubation, at least one dilution level yielded 6–60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae, SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

  1. AM真菌摩西球囊霉对2种花生叶斑病的生防及促生作用%Biocontrol Effects of AM Fungus Glomus mosseae on Two Peanut Leaf Spots and its Growth-promoting Effects on Peanut

    Institute of Scientific and Technical Information of China (English)

    鄢洪海; 张茹琴; 安佰国

    2011-01-01

    为了研究丛枝菌根(Arbuscular mycorrhiza,AM)真菌对2种花生叶部病害黑斑病(Cercosporium personatuma)和网斑病(Phoma arachidicola)的生物防治作用以及对花生生长的促进作用,为开发绿色菌肥奠定基础,在盆栽条件下对花生品种‘花育22号’接种AM真菌摩西球囊霉(Glomus mosseae),在自然发病情况下,测定摩西球囊霉接种对花生黑斑病和网斑病的防治效果以及对花生株高、分枝、果荚数、果荚干重、地上部干重、地下部干重等生长指标的影响.结果表明,接种AM真菌摩西球囊霉使花生株高、分枝、荚果数、荚果干重、地上部干重等生长指标显著地增加;对花生黑斑病防治效果为5.4%,对网斑病防治效果为10.2%.AM通过促进花生生长而补偿了病害造成的损失是其抗病机制之一.表明分离的摩西球囊霉是一株具有促进花生生长,对2种叶部病害具有一定生防作用的AM菌株.%In order to study biocontrol effects of arbuscular mycorrhizal (AM) on two leaf spots, peanut (Arachis hypogaea L.) black spot (Cercosporium personatuma) and peanut net blotch {Phoma arachidicola), the growth-promoting effects of AM fungus on peanut, and as a result, laying a foundation for the development of green manure, peanut cultivar ' Huayu 22' inoculated with AM fungus Glomus mosseae in a pot experiment, under natural infection conditions, biocontrol effects of G. Mosseae on peanut black spot and peanut net blotch, growth indices including plant height, the numbers of branches or pods, dry mass of pods, aboveground or underground dry mass of peanut were investigated. The results indicated that, inoculation peanut with G. Mosseae significantly improved plant height, the numbers of branches or pods, dry mass of pods, aboveground dry mass of peanut, and induced systemic acquired resistance to the two leaf spots. Control effect on peanut black spot was 5.4%, whereas on net peanut blotch was 10.2%. One of

  2. Rocky Mountain Spotted Fever

    Science.gov (United States)

    ... facebook share with twitter share with linkedin Rocky Mountain Spotted Fever Rocky Mountain spotted fever is a ... New Mexico. Why Is the Study of Rocky Mountain Spotted Fever a Priority for NIAID? Tickborne diseases ...

  3. Are 'hot spots' hot spots?

    Science.gov (United States)

    Foulger, Gillian R.

    2012-07-01

    The term 'hot spot' emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a 'normal' mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ˜200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40-50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200-300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been

  4. 越南对抗角斑病棉花品种的选育(英)%Screening of Promising Cotton Varieties for Bacterial Blight Resistance

    Institute of Scientific and Technical Information of China (English)

    Bui Thi Ngan

    2002-01-01

    @@ I Introduction Bacterial Blight (Xanthomonas malvacearum ,BB) was probably originated in India, although the disease was first reported in the USA by Atkinson (1891), who gave the names angular leaf spot, blackarm and bacterial boll rot to the various stages in the syndrome of the disease. The first programme to breed for cultivar resistance to the disease was initiated in Sudan by research officers with the Cotton Research Corporation. Methods adopted there were soon implemented in Uganda and most of the early resistant varieties grown in many African countries were derived from the Uganda programme.

  5. Seleção de linhagens de feijão rosinha de boa cocção, resistentes à antracnose e mancha angular Selection of pink grain common bean lines with good cooking ability, resistance to anthracnose and angular leaf spot

    Directory of Open Access Journals (Sweden)

    Diego Velásquez Faleiro e Silva

    2009-09-01

    Full Text Available Cultivares de feijoeiro com grão rosinha foram de grande importância, no passado, e ainda hoje, mesmo com a preferência pelo grão carioca, há nichos de mercado para feijões do grupo Rosinha. Dessa forma, o objetivo do trabalho foi selecionar linhagens de feijoeiro comum com grão rosinha, alta produção de grãos, rápido cozimento e resistentes à antracnose e à mancha angular. A partir de cinco famílias F8 superiores, provenientes do cruzamento entre os genitores Rosinha Maria da Fé e ESAL 693, foram extraídas 143 linhagens as quais foram avaliadas na safra das águas de 2005/2006 em Lavras (MG. Dessas, manteve-se 99 linhagens que foram avaliadas em Lavras e Lambari (MG, na safra da seca de 2006. As 24 linhagens selecionadas foram novamente avaliadas nos dois locais, no inverno de 2006. Os caracteres avaliados foram produção e tipo de grão, tempo de cocção, reação à mancha angular e também, foi realizado o teste de resistência ao patótipo 65 de Colletotrichum lindemuthianum. Nas linhagens, observaram-se variabilidade genética para todos os caracteres avaliados, altas estimativas dos coeficientes de herdabilidade, assegurando elevados ganhos com a seleção. Foram selecionadas quatro linhagens com alta produção, tipo de grão ideal, com rápido tempo de cocção e resistência à mancha angular e à antracnose.Common bean cultivars with pink grain type used to be very important, although there is still some market spot for them. The objective of the research was to select common bean lines with pink grain, high grain yield with good cooking ability, and resistance to anthracnose and angular leaf spot. One hundred and forty three lines were selected from five F8 segregant families derived from the cross Rosinha Maria da Fé x ESAL 693. Those lines were evaluated in the rainy season of 2005/2006 at Lavras county, MG State. Ninety nine lines were kept and tested in the dry season of 2006 at Lavras and Lambari. The 24

  6. Differential Proteomic Analysis of Leaf Development at Rice (Oryza sativa)Seedling Stage

    Institute of Scientific and Technical Information of China (English)

    SHAO Cai-hong; LIU Guang-rong; WANG Jing-yuan; YUE Cai-fei; LIN Wen-xiong

    2008-01-01

    To identify the function of differential expression proteins in different leaves of rice seedlings extracted from 2- to 5-leaf stages,the leaf proteins at the seedling stage of hybrid rice Shanyou 63 were studied by using the approach of plant proteomics,and those proteins were separated with two-dimensional electrophoresis (2-DE) and then analyzed with an imagemaster 2D Elite 5.0.The results showed that the 41 protein spots were detected differential expression,of which 17 new protein spots appeared after the 3-leaf stage,including 9 special protein spots,which were only detected at the 3-leaf stage.Thirteen protein spots increased first and then decreased in expression abundance gradually and finally even disappeared.For the other 11 protein spots,3 protein spots decreased,but 6 protein spots were opposite in expression abundance,however,2 protein spots expressed in an irregular pattern after the 2-leaf stage.Of the 41 differential leaf proteins,15 protein spots were identified by ESI-Q MS/MS and categorized into 4 groups of functions.The results indicated that proteins were the carders of the functions in cells,but were significantly influenced by the changes in cell function or intercellular environment;hence,the reason that caused the proteomic changes as mentioned earlier might be related to the occurrence of tillers at the rice seedling stage after the 3-leaf stage.

  7. Productivity and biochemical properties of green tea in response to full-length and functional fragments of HpaGXooc, a harpin protein from the bacterial rice leaf streak pathogen Xanthomonas oryzae pv. oryzicola

    Indian Academy of Sciences (India)

    Xiaojing Wu; Tingquan Wu; Juying Long; Qian Yin; Yong Zhang; Lei Chen; Ruoxue Liu; Tongchun Gao; Hansong Dong

    2007-09-01

    Harpin proteins from plant pathogenic bacteria can stimulate hypersensitive cell death (HCD), drought tolerance, defence responses against pathogens and insects in plants, as well as enhance plant growth. Recently, we identified nine functional fragments of HpaGXooc, a harpin protein from Xanthomonas oryzae pv. oryzicola, the pathogen that causes bacterial leaf streak in rice. Fragments HpaG1–94, HpaG10–42, and HpaG62–138, which contain the HpaGXooc regions of the amino acid sequence as indicated by the number spans, exceed the parent protein in promoting growth, pathogen defence and HCD in plants. Here we report improved productivity and biochemical properties of green tea (Camellia sinensis) in response to the fragments tested in comparison with HpaGXooc and an inactive protein control. Field tests suggested that the four proteins markedly increased the growth and yield of green tea, and increased the leaf content of tea catechols, a group of compounds that have relevance in the prevention and treatment of human diseases. In particular, HpaG1–94 was more active than HpaGXooc in expediting the growth of juvenile buds and leaves used as green tea material and increased the catechol content of processed teas. When tea shrubs were treated with HpaHXooc and HpaG1–94 compared with a control, green tea yields were over 55% and 39% greater, and leaf catechols were increased by more than 64% and 72%, respectively. The expression of three homologues of the expansin genes, which regulate plant cell growth, and the CsCHS gene encoding a tea chalcone synthase, which critically regulates the biosynthesis of catechols, were induced in germinal leaves of tea plants following treatment with HpaG1–94 or HpaGXooc. Higher levels of gene expression were induced by the application of HpaG1–94 than HpaGXooc. Our results suggest that the harpin protein, especially the functional fragment HpaG1–94, can be used to effectively increase the yield and improve the biochemical

  8. Development of genomic resources for the narrow-leafed lupin (Lupinus angustifolius): construction of a bacterial artificial chromosome (BAC) library and BAC-end sequencing

    Science.gov (United States)

    2011-01-01

    Background Lupinus angustifolius L, also known as narrow-leafed lupin (NLL), is becoming an important grain legume crop that is valuable for sustainable farming and is becoming recognised as a potential human health food. Recent interest is being directed at NLL to improve grain production, disease and pest management and health benefits of the grain. However, studies have been hindered by a lack of extensive genomic resources for the species. Results A NLL BAC library was constructed consisting of 111,360 clones with an average insert size of 99.7 Kbp from cv Tanjil. The library has approximately 12 × genome coverage. Both ends of 9600 randomly selected BAC clones were sequenced to generate 13985 BAC end-sequences (BESs), covering approximately 1% of the NLL genome. These BESs permitted a preliminary characterisation of the NLL genome such as organisation and composition, with the BESs having approximately 39% G:C content, 16.6% repetitive DNA and 5.4% putative gene-encoding regions. From the BESs 9966 simple sequence repeat (SSR) motifs were identified and some of these are shown to be potential markers. Conclusions The NLL BAC library and BAC-end sequences are powerful resources for genetic and genomic research on lupin. These resources will provide a robust platform for future high-resolution mapping, map-based cloning, comparative genomics and assembly of whole-genome sequencing data for the species. PMID:22014081

  9. Loss of outer membrane integrity in Gram-negative bacteria by silver nanoparticles loaded with Camellia sinensis leaf phytochemicals: plausible mechanism of bacterial cell disintegration

    Indian Academy of Sciences (India)

    M SINGH; A K MALLICK; M BANERJEE; R KUMAR

    2016-12-01

    New generation antimicrobial and smart drugs are the needs of the present era in fighting microbial infection and various chronic diseases. Nowadays nanoparticles (NPs) are widely applied in biomedical fields by virtue of their surface modification, which enhances both target selectivity and function. This study is a continuation of our earlier study that demonstrated antimicrobial property of NPs against both Gram-positive and Gramnegative organisms (Goswami et al, 2015). Silver NPs were synthesized using tea leaves (Camellia sinensis) decoction and were characterized using UV-vis spectrophotometry, transmission electron microscopy (TEM) and Fouriertransformed infrared spectroscopy (FTIR). The silver NPs were stable at various environmental conditions. The stability of the particles may be due to various phytochemicals of tea that were bound to the surface of reducedsilver ions as a capping agent. The antimicrobial activity of NP was investigated against three Gram-negative pathogenic bacteria (Shigella dysentriae, Salmonella infestis and Vibrio parahaemolyticus). The outer membrane ofGram-negative bacteria is a lipopolysaccharide (LPS) in nature and provides protection from various stress conditions and antibiotics. But a silver NP destroys its membrane integrity and thus helps in cell killing. Spectral changesconfirmed NP interaction with hydrophobic moiety of LPS. Minimum inhibitory concentrations for S. dysentriae, S. infestis and V. parahaemolyticus were 3.75, 5.25 and 5.25 $\\mu$g ml$^{−1}$, respectively. Inhibition of biofilm formationwas significant with the three bacterial strains. Cytoplasmic leakage from each bacterial strain was also demonstrated on account of NP treatment. The particles demonstrated good biocompatibility. No damage of human buccal mucosal cells was recorded even at concentration of 10 mg ml$^{−1}$. Thus, silver NPs would be potential oral therapeutic molecules against Gram-negative bacteria.

  10. Development and Validation of an Infection Risk Model for Bacterial Canker of Kiwifruit, Using a Multiplication and Dispersal Concept for Forecasting Bacterial Diseases.

    Science.gov (United States)

    Beresford, R M; Tyson, J L; Henshall, W R

    2017-02-01

    A weather-based disease prediction model for bacterial canker of kiwifruit (known worldwide as Psa; Pseudomonas syringae pv. actinidiae biovar 3) was developed using a new mechanistic scheme for bacterial disease forecasters, the multiplication and dispersal concept. Bacterial multiplication is estimated from a temperature function, the M index, accumulated from hourly air temperature over 3 days for hours when the leaf canopy is wet. Rainfall provides free water to move inoculum to infection sites, and the daily risk indicator, the R index, is the 3-day accumulation of the M index output on days with total rainfall >1 mm; otherwise, R is zero. The model was field-tested using potted kiwifruit trap plants exposed for discrete periods in infected kiwifruit orchards to identify when leaf infection occurred. In a 9-week study during spring, the R index predicted leaf-spot intensity with high accuracy (R(2) = 93%) and, in an 82-week seasonal accuracy study, prediction of infection incidence was most accurate from spring to late summer and lower during other times. To implement the risk model for the New Zealand kiwifruit industry, a modified risk index, R', used relative humidity (RH) >81% instead of wetness, so that 2- and 6-day weather forecasts of RH could be used. Risk index values were affected by the shape of the temperature function and an alternative 'low temperature' function for the M index was identified that could be used in climates in which high temperatures are known to limit Psa development during some parts of the year. This study has shown how infection risk for bacterial diseases can be conceptualized as separate processes for temperature-dependent bacterial multiplication and rain-dependent dispersal and infection. This concept has potentially wide application for bacterial disease prediction in the same way that the infection monocycle concept has had for fungal disease prediction.

  11. An HPLC-MS characterization of the changes in sweet orange leaf metabolite profile following infection by the bacterial pathogen Candidatus Liberibacter asiaticus.

    Directory of Open Access Journals (Sweden)

    Faraj M Hijaz

    Full Text Available Huanglongbing (HLB presumably caused by Candidatus Liberibacter asiaticus (CLas threatens the commercial U.S. citrus crop of an annual value of $3 billion. The earliest shift in metabolite profiles of leaves from greenhouse-grown sweet orange trees infected with Clas, and of healthy leaves, was characterized by HPLC-MS concurrently with PCR testing for the presence of Clas bacteria and observation of disease symptoms. Twenty, 8-month-old 'Valencia' and 'Hamlin' trees were grafted with budwood from PCR-positive HLB source trees. Five graft-inoculated trees of each variety and three control trees were sampled biweekly and analyzed by HPLC-MS and PCR. Thirteen weeks after inoculation, Clas was detected in newly growing flushes in 33% and 55% of the inoculated 'Hamlin' and 'Valencia' trees, respectively. Inoculated trees remained asymptomatic in the first 20 weeks, but developed symptoms 30 weeks after grafting. No significant differences in the leaf metabolite profiles were detected in Clas-infected trees 23 weeks after inoculation. However, 27 weeks after inoculation, differences in metabolite profiles between control leaves and those of Clas-infected trees were evident. Affected compounds were identified with authentic standards or structurally classified by their UV and mass spectra. Included among these compounds are flavonoid glycosides, polymethoxylated flavones, and hydroxycinnamates. Four structurally related hydroxycinnamate compounds increased more than 10-fold in leaves from 'Hamlin' and 'Valencia' sweet orange trees in response to Clas infection. Possible roles of these hydroxycinnamates as plant defense compounds against the Clas infection are discussed.

  12. Rocky Mountain spotted fever

    Science.gov (United States)

    ... Mountain spotted fever is caused by the bacteria Rickettsia rickettsii (R. Rickettsii) , which is carried by ticks. ... Saunders; 2014:chap 212. Walker DH, Blaton LS. Rickettsia rickettsii and other spotted fever group rickettsiae (Rocky ...

  13. Effect of crop density of two genotypes of maize in the severity of gray leaf spot and yield in the second season cropInfluência da densidade de cultivo de dois genótipos de milho na severidade da mancha de cercospora e no rendimento de grãos na safrinha

    Directory of Open Access Journals (Sweden)

    Luis Gustavo Amorim Pessoa

    2012-08-01

    Full Text Available Among the diseases that affect the corn crop and can reduce the yield, there is cercospora gray leaf, caused by Cercospora spp. This disease is very important in the second season crop or ‘safrinha’. The objective of this study was to evaluate the severity of cercospora leaf spot in transgenic corn hybrids Agroceres Yieldgard AG 9010 YG and Advance NK Agrisure TL (Bt11, using two plant densities: 78,000 and 100,000 plants per hectare. The results showed that the higher density of plants increased the severity of the disease and provided a lower yield. There was no significant interaction between hybrids and severity of the disease. Entre as doenças que incidem na cultura do milho e podem reduzir seu rendimento, há a mancha de cercospora, causada por Cercospora spp., especialmente importante em milho de segunda época, ou ‘safrinha’. O objetivo deste trabalho foi avaliar a severidade da cercosporiose em nos híbridos transgênicos de milho Agroceres Yieldgard AG 9010 YG e Advance NK Agrisure TL (Bt11, em duas densidades de cultivo: 78.000 e 100.000 plantas por hectare. Os resultados permitiram constatar que a menor densidade de plantas favoreceu o incremento da severidade da doença e proporcionou menor rendimento de grãos. Não houve interação significativa entre os híbridos e a severidade da doença.

  14. Crestamento foliar, nova sintomatologia em algodoeiro causada por Xanthomonas axonopodis pv. malvacearum Cotton leaf blight, a new symptomatology caused by Xanthomonas axonopodis pv. malvacearum

    Directory of Open Access Journals (Sweden)

    Valdemar Atílio Malavolta Jr.

    2008-06-01

    Full Text Available Foi observada recentemente no Estado de São Paulo uma nova sintomatologia em algodoeiro cv. Makina, IAC 24 e Detaopal, causada por Xanthomonas axonopodis pv. malvacearum (Xam, denominada "crestamento foliar". Caracteriza-se por crestamento foliar, geralmente acompanhado por halo clorótico, podendo também causar sintomas de "V" invertido, a partir dos bordos foliares. Linhagens de Xam foram comparadas, por meio de testes de patogenicidade, bioquímicos, sorológicos, culturais e PCR-RFLP da região espaçadora 16S-23S DNAr. Independentemente do tipo de sintoma, as linhagens apresentaram características e perfis idênticos aos apresentados pela linhagem tipo, confirmando a identidade dos isolados como Xanthomonas axonopodis pv. malvacearum.Recently a new symptomatology on cotton plants (cv. Makina, IAC 24 and Deltaopal caused by Xanthomonas axonopodis pv. malvacearum (Xam was observed in São Paulo state, Brazil, and named "bacterial leaf blight". The symptom was characterized by leaf blight, generally exhibiting chlorotic haloes and sometimes showing V-shaped lesions beginning at the leaves' border. Strains of Xam responsible for typical angular leaf spots and bacterial leaf blight were compared through pathological, biochemical, serological, cultural and RFLP-PCR tests of the 16S-23S spacer region. Independently of the symptom type, the strains exhibited characteristics and profiles that were identical to those exhibited by the type strain, which confirms the isolates identity Xanthomonas axonopodis pv. malvacearum

  15. Improvement of Bacterial Leaf Blight Resistance of Wenhui 117 by Molecular Marker-assisted Selection%利用分子标记辅助选择改良温恢117白叶枯病抗性

    Institute of Scientific and Technical Information of China (English)

    罗天宽; 张小玲; 杨文清; 卢华金; 朱世杨; 荆赞革; 唐征; 刘庆

    2011-01-01

    以恢复系温恢117为受体,以IRBB21为抗白叶枯病基因Xa21的供体,通过杂交、多次回交和自交,结合分子标记辅助选择技术,将Xa21基因导入温恢117中,结合抗性基因Xa21的分子检测和农艺性状表现,筛选出带有Xa21基因的15个恢复系株系.采用白叶枯病菌株的专化强毒菌系P6进行接种鉴定,各株系的白叶枯病抗性均强于受体亲本温恢117,其中株系M033抗性与IRBB21相当,而农艺性状与温恢117相近.%Using Wenhui 117, an elite restorer line in rice, as the receptor and IRBB21 as the donor of a gene to bacterial leaf blight(BLB) resistance, the resistant gene Xa21 was introduced into rice restorer lines through crossing and backcrossing with the molecular marker-assisted selection. 15 restorer lines carrying the gene Xa21 were acquired based on the molecular marker test and agronomic performance. A subsequent inoculation identification of BLB resistance was conducted to these improved lines with the gene Xa21 . It was found that all of the improved lines had a better BLB resistance than the receptor Wenhui 117. Among them, the line M033 had both such a high BLB resistance as the donor IRBB21 and similar agronomic characteristics to the receptor Wenhui 117.

  16. Functional overlap of the Arabidopsis leaf and root microbiota.

    Science.gov (United States)

    Bai, Yang; Müller, Daniel B; Srinivas, Girish; Garrido-Oter, Ruben; Potthoff, Eva; Rott, Matthias; Dombrowski, Nina; Münch, Philipp C; Spaepen, Stijn; Remus-Emsermann, Mitja; Hüttel, Bruno; McHardy, Alice C; Vorholt, Julia A; Schulze-Lefert, Paul

    2015-12-17

    Roots and leaves of healthy plants host taxonomically structured bacterial assemblies, and members of these communities contribute to plant growth and health. We established Arabidopsis leaf- and root-derived microbiota culture collections representing the majority of bacterial species that are reproducibly detectable by culture-independent community sequencing. We found an extensive taxonomic overlap between the leaf and root microbiota. Genome drafts of 400 isolates revealed a large overlap of genome-encoded functional capabilities between leaf- and root-derived bacteria with few significant differences at the level of individual functional categories. Using defined bacterial communities and a gnotobiotic Arabidopsis plant system we show that the isolates form assemblies resembling natural microbiota on their cognate host organs, but are also capable of ectopic leaf or root colonization. While this raises the possibility of reciprocal relocation between root and leaf microbiota members, genome information and recolonization experiments also provide evidence for microbiota specialization to their respective niche.

  17. Cedar leaf oil poisoning

    Science.gov (United States)

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  18. 香蕉突脐蠕孢叶斑病菌Brn1基因的PCR扩增与序列分析%PCR amplification and sequence analysis of Brn1 gene of Exserohilum rostratum causing banana leaf spot disease

    Institute of Scientific and Technical Information of China (English)

    林善海; 黄思良; 覃丽萍; 胡春锦; 余功明; 付岗

    2011-01-01

    [目的]为从分子水平进一步鉴定引起香蕉叶斑病的突脐蠕孢霉,对突脐蠕孢的Brn1基因序列进行了分析.[方法]用引物Brn1 01(5'-GCCAACATCGCAAACATGG-3’)and Brn1 02(5’-GCAAGCAGCACCGTCAATACCAAT-3')对3个分生孢子形态差异较大的香蕉突脐蠕孢叶斑病菌(CLER09 、D087和JL05)的Brn1基因进行PCR扩增和系统发育分析.[结果]不同菌株间存在简单的碱基缺失和替换,供试菌株与Exserohilum rostratum在系统发育树上聚类在同一个分支,与Exserohilum属其他种明显分开,形成一个独立的演化群.遗传距离分析表明,供试菌株与E.rostratum亲缘关系相近,菌株间的遗传距离为0.000~0.018,而Exserohilum属种间的遗传距离为0.020~0.093.[结论]E.rostratum菌株间的遗传变异较大,但仍属种内变异;Brn1基因可作为支持具有明显形态变异菌株为E.rostratum成员的分子依据.%[Objective]Different strains of Exserohilum rostratum,causing exserohilum banana leaf spot disease were characterized at molecular level using the conserved sequence of Brn1 gene.[Method] Brn1 gene of three pathogenic isolates (CLER09,D087 and JL05) of E.rostratum causing exserohilum banana leaf spot disease was amplified using primer pair Brn1 01 (5'-GCCAACATCGCAAACATGG-3') and Brn1 02 (5'-GCAAGCAGCACCGTCAATACCAAT-3'),and phylogenetic analysis was carried out.[Result] The results showed absence and substitute of single bases in Brn1 sequences among different isolates of E.rostratum isolated from diseased banana plant and sequence collected from GenBank database.The isolates collected from banana were clustered with E.rostratum in an absolute evolution group in the phylogenetic tree,and significantly distinguished from other species of Exserohilum spp.Analysis result of the genetic distance matrix showed that tested isolates were genetically close to E.rostratum sequences collected from GenBank database with intraspecies genetic distance of 0.000-0.018 and

  19. 二比空栽培模式对玉米弯孢菌叶斑病流行动态影响%Effects of Two-one Row Interval Cultivation Pattern on the Epidemiology of Curvularia Leaf Spot of Maize

    Institute of Scientific and Technical Information of China (English)

    景殿玺; 刘震; 周如军; 傅俊范

    2013-01-01

    根据植物病害流行学原理,通过田间试验设计及人工接种技术,对二比空栽培模式与常规栽培模式下玉米弯孢菌叶斑病发生流行动态进行比较研究。结果表明,二比空栽培模式的发病程度轻于常规栽培模式,病害初始病情与传播速率均低于常规模式。病害流行时间动态模型拟合发现,Weibull模型较好,其中,两种栽培模式下病害指数增长期(始发期)相同,二比空栽培模式下病害Weibull增长期(盛发期)短于常规模式,且衰退期出现较早。%Based on the principles of plant disease epidemics, the field trial design and artificial inoculation were conducted for comparing the occurrence and epidemics of curvularia leaf spot of maize disease between under the two-one row interval cultivation mode and conventional cultivation mode. The disease under the two-one row interval cultivation mode presented a less disease severity than the conventional cultivation mode. The initial disease symptoms and transmission rate were lower in two-one row interval cultivation mode than the conventional cultivation mode. The dynamic patterns of disease epidemics fitted the model of Weibull. Two maize cultivation modes showed a similar dis-ease exponential period(initiation period). The disease in the two-one row interval cultivation mode had a shorter growth period and an earlier recession period than the conventional cultivation mode.

  20. 利用酵母双杂交筛选与苹果褪绿叶斑病毒CP互作的寄主因子%Screening of the Host Factors Interacting with CP ofApple chlorotic leaf spot virusby Yeast Two-Hybrid System

    Institute of Scientific and Technical Information of China (English)

    何乙坤; 钟敏; 胡同乐; 王树桐; 段豪; 丁丽; 王亚南; 曹克强

    2014-01-01

    Objective] The objective of this study is to screen the host factors interacting with coat protein (CP) ofApple chlorotic leaf spot virus (ACLSV) by yeast two-hybrid system and analyze their function in the interaction between host and virus by the method of bioinformatics.[Method] Firstly, the bait vector of pGBKT7-CP was constructed and transformed into Y2H gold. The growth of the transformed yeast was assayed on the culture plate of SD/-Trp, SD/-Trp/-His and SD/-Trp/-Ade-X-α-Gal to make clear the self-activating effect of pGBKT7-CP. The plasmids of pGBKT7-CPand pGBKT7 were transformed intoY2H gold, the OD 600 of which was tested by ultraviolet spectrophotometer at different stages. The effect of pGBKT7-CP on the yeast was analyzed. Secondly, the interactive proteins of CP were screened from cDNA library ofMalus sylvestris cv. R12740-7A constructed early by yeast two-hybrid sequencing transformation. At last, the positive clones were selected from the culture plate of SD/-Ade/-His/-Leu/-Trp/X-α-Gal and sequenced. BLAST analysis was made for the host factors in the GenBank and the function in the interaction between host and virus was deduced based on gene annotation.[Result] The bait vector of pGBKT7-CP was constructed. The transformed yeast Y2H gold was able to grow on the plate of SD/-Trp, but not able to grow on the plate of SD/-Trp/-His and SD/-Trp/-Ade-X-α-Gal, which implied that the recombined plasmid had no ability to activate the reporter gene of His and Ade.The growth of pGBKT7-CPand the control was similar, which predicated that the recombined plasmid had no virulence to the yeast. Sixty-nine interactive factors were obtained, which were divided into 10 types of proteins based on their functions, including transcription factor activity, carbon fixation activity, cellular iron ion homeostasis, defense response, hydrolase activity, oxidase activity, oxidoreductase activity, photosystem II assembly and protein binding activity. Eight host genes (Malus3

  1. Antibacterial activity of mangrove leaf extracts against human pathogens

    Digital Repository Service at National Institute of Oceanography (India)

    Sahoo, G.; Mulla, N.S.S.; Ansari, Z.A.; Mohandass, C.

    The antibacterial activity of leaf extract of mangroves, namely, Rhizophora mucronata, Sonneratia alba and Exoecaria agallocha from Chorao island, Goa was investigated against human bacterial pathogens Staphylococcus aureus, Streptococcus sp...

  2. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  3. Spotted Seal Distribution Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of spotted seals (Phoca largha). It was...

  4. Mononucleosis spot test

    Science.gov (United States)

    Monospot test; Heterophile antibody test; Heterophile agglutination test; Paul-Bunnell test; Forssman antibody test ... The mononucleosis spot test is done when symptoms of mononucleosis are ... Fatigue Fever Large spleen (possibly) Sore throat Tender ...

  5. Evaluation of plant activator and chemical fungicides on leaf blight (Bipolaris sorokiniana) development and yield of wheat.

    Science.gov (United States)

    Aminuzzaman, F M; Hossain, I

    2007-06-01

    Bion 50 WG (Benzothiodiazole), Tilt-250 EC (Propiconazole) and Amistar (Azoxystrobin) either alone and some of their combinations were evaluated against leaf blight/spot (Bipolaris sorokiniana) development and yield of wheat. All the treatments significantly reduced leaf spot reaction of wheat over untreated control. But Bion in combination with Amistar resulted significantly highest reduction of leaf spot reaction of wheat (p = 0.05) against all the tested pathotypes inoculated at flag leaf stage. In the field, Bion reduced leaf spot severity at heading and flowering stage in 2000-2001 and at hard dough stage in 2001-2002. Number of grains/ear not significantly increased by treating seeds with Bion though 1000-grain weight is significantly increased (p = 0.05) in 2000-2001 by Bion. Statistically higher grain yield was obtained from the experimental plot by treating seeds with Bion and Amistar. Bion resulted 53.33% higher grain yield in compare to untreated control.

  6. Brief History of Cercospora Leaf Spot of Sugar Beet

    Science.gov (United States)

    Sugar beet (Beta vulgaris L.) is most likely native to western and southern Asia and is believed to have arrived in Europe via the Mediterranean countries through Egypt. The cultivation of sugar beet as an alternate source of sugar is attributed Andreas Siegmund Marggraf in the 1740s. Subsequent pro...

  7. narrow sense heritability and gene effects for late leaf spot ...

    African Journals Online (AJOL)

    ACSS

    The Bi parental mating design was employed, where three crosses ... have been raised in the same environment, (ii) only autosomal ..... North. Carolina Cooperative Extension Service,. College of Agriculture & Life Sciences North. Carolina ...

  8. Effect of leaf surface waxes on leaf colonization by Pantoea agglomerans and Clavibacter michiganensis.

    Science.gov (United States)

    Marcell, Lise M; Beattie, Gwyn A

    2002-12-01

    To evaluate the influence of leaf cuticular waxes on bacterial colonization of leaves, bacterial colonization patterns were examined on four glossy maize (Zea mays L.) mutants that were altered in their cuticular wax biosynthesis. Mutant gl3 was indistinguishable from the wild-type maize in its ability to foster colonization by the two bacterial species, Pantoea agglomerans and Clavibacter michiganensis subsp. nebraskensis. In contrast, the other three mutants supported the development of populations that significantly differed in size from those on the wild type. Mutant gl5 gl20 supported smaller populations of P. agglomerans, but not C. michiganensis, while mutant gl1 supported larger populations of C. michiganensis but not P. agglomerans. Mutant gl4 supported larger populations of both bacterial species. The exceptional ability of mutant gl4 to support bacterial colonization was hypothesized to result from the lower density of the crystalline waxes on gl4 than on the wild type, because a reduced crystal density could promote capillary water movement and water trapping among the wax crystals. This hypothesis was supported by the demonstration that the mechanical introduction of gaps among the wax crystals of the wild-type leaves resulted in the establishment of larger P. agglomerans populations on the altered leaves. These results provide the first direct evidence that leaf surface waxes affect bacterial leaf colonization at various stages of colonization and in a bacterial species-dependent manner.

  9. LEAF DISEASE SEVERITY MEASUREMENT USING IMAGE PROCESSING

    Directory of Open Access Journals (Sweden)

    Sanjay B. Patil

    2011-10-01

    Full Text Available Fungi-caused diseases in sugarcane are the most predominant diseases which appear as spots on the leaves. If not treated on time, causes the severe loss. Excessive use of pesticide for plant diseases treatment increases the cost and environmental pollution so their use must be minimized. This can be achieved by targeting the diseases places, with the appropriate quantity and concentration of pesticide by estimating disease severity using image processing technique. Simple threshold and Triangle thresholding methods are used to segment the leaf area and lesion region area respectively. Finally diseases are catcogrise by calculating the quotient of lesion area and leaf area. The accuracy of the experiment is found to be 98.60 %. Research indicates that this method to calculate leaf disease severity is fast and accurate.

  10. 莴苣叶斑病菌的分离鉴定及弱毒菌株致病力的衰退%Isolation of the pathogens causing leaf spot of lettuce and analysis of the reason causing the attenuated virulence

    Institute of Scientific and Technical Information of China (English)

    潘显婷; 陆训; 庞茜丹; 高必达; 周倩

    2016-01-01

    Fourstrains were isolated from lettuce with leaf spot disease by tissue isolation method and identified as Stemphyliumspp. with ITS sequences analysis. An attenuated strain with debilitated pathogenicity and slower growth rate named WS–01 was found by artifical inoculation. The cellulose CF11 method was used to extract dsRNA to determine the relation between the debilitated pathogenicity and its dsRNA mycovirus, three dsRNAs ranged from 1 kb to 5 kb were detected in the WS–01 strain. High temperature-ribavirin-hyphal tip isolation method for elimination of virus was conducted. The results showed that the pathogenicity of mycovirus-eliminated strain WS–01–D was enhanced and the phenotype returned to normal compared to the original strain, indicating the abnormal phenotype of strain WS–01 was related to its dsRNA.%利用组织分离法,从感染叶斑病的莴苣叶片上分离得到4株真菌,ITS序列分析鉴定为匍柄霉(Stemphylium spp.)。科赫氏法则验证其致病性时发现,菌株 WS–01较其他菌株致病力减弱,且生长缓慢。用纤维素吸附法提取菌株WS–01的dsRNA,发现WS–01含有3条1~5 kb的dsRNA条带,提示WS–01菌株内含有dsRNA病毒。利用高温–利巴韦林–尖端脱毒结合的方法消除WS–01内的病毒,所得菌株WS–01–D与菌株WS–01相比,致病性增强且表型恢复正常,提示弱毒菌株WS–01的致病力减弱与其所含dsRNA有关。

  11. 双株定向栽培模式对玉米弯孢菌叶斑病发生流行及玉米产量的影响%Effects of Two-plants Orientation Cultivation Pattern on the Maize Yield and Occurrence and Epidemic of Curvularia Leaf Spot

    Institute of Scientific and Technical Information of China (English)

    李金堂; 默书霞

    2015-01-01

    Through the field experiments for two years, influences of two-plants orientation cultivation pattern and conventional cultivation pattern on the occurrence and epidemic and maize yield of curvularia leaf spot were studied. The results showed that the disease was even more severe under two-plants orientation cultivation pattern than that of conventional cultivation pattern and the disease differences was more obvious under suitable environ⁃mental conditions. Epidemic phases under the two cultivation patterns derived from the Logistic models showed that the exponential growth period and recession period under two-plants orientation cultivation pattern were more short⁃er than those of conventional cultivation pattern and the logistic growth phase was 4 to 5 days longer accordingly which indicated that two-plants orientation cultivation pattern was more favorable to disease epidemic. Maize yield under two-plants orientation cultivation pattern was higher than that of conventional cultivation pattern, but with the expansion of the disease differences, this will reduce the yield advantage.%通过两年田间小区试验,观察比较双株定向栽培模式和常规栽培模式下玉米弯孢菌叶斑病发生流行动态及对玉米产量的影响。结果表明,双株定向栽培模式下玉米弯孢菌叶斑病的病情重于常规栽培模式,适合病害发生的环境条件下病情差异更为明显。应用Logistic模型推导两种栽培模式下病害的流行时期,双株定向栽培模式的指数增长期及衰退期较常规栽培模式短,而逻辑斯蒂增长期则长4~5 d,说明双株定向栽培模式更适合病害的发生与流行。双株定向栽培的玉米产量高于常规栽培,但随着两者病情差距的扩大,增产优势会降低。

  12. Efficacy of Fungicides and Spatial Distribution of Angular Leaf Spot on Tripterygium wilfordii Infected by Pseudocercospra elaeodendri%雷公藤角斑病菌的室内毒力测定及病害空间分布格局研究

    Institute of Scientific and Technical Information of China (English)

    谢婉凤; 郭文硕; 冯丽贞; 苏良玉; 叶小真; 黄秀萍; 刘金燕

    2014-01-01

    用8种真菌杀菌剂防治雷公藤角斑病,室内孢子毒力试验表明:孢子萌发抑制效果以75%百菌清可湿性粉剂最好, EC50=0.49 mg · L-1, EC=0.78 mg · L-1,其次是25%腐霉利可湿性粉剂,80%代森锰锌可湿性粉剂。浓度70 mg · L-1嘧霉胺及100 mg · L-1的异菌脲、甲基硫菌灵、三唑酮对分生孢子萌发的抑制率均小于10%。通过聚集度指标法的测定、Iwao的回归分析法和 Taylor 的幂法则对雷公藤角斑病的空间分布格局进行研究,结果表明,雷公藤角斑病病株在林间为均匀分布。%Efficacy of 8 fungicides was examined in vitro on the germination of Pseudocercospra elaeodendri .The best effect of the fungicides was the 75% mass fraction chlorothalonil WP with EC50 =0.49 mg · L -2 ,EC= 0.78 mg · L -2 ,followed by the 25% mass fraction procymidone thiram WP ,and then ,the 80% mass fraction mancozeb WP .Spore germination inhibition rates of < 10% were found for pyrimethanil (70 mg · L -2 ) ,iprodione (100 mg · L -1 ) ,thiophanate-metlyl (100 mg · L -1 ) and tradimefon (100 mg · L -1 ) after 7 h incubation .Based on the aggregation indices ,Iwao′s regression and Taylor′s power law ,the spatial distribution pattern of the angular leaf spot of Tripterygium wilfordii was found to be uniform in the area′s forests .

  13. Report of Sclerotinia sclerotiorum as the causal organism of the leaf ...

    African Journals Online (AJOL)

    SARAH

    2015-06-30

    Jun 30, 2015 ... organism of the leaf spot and stem blight disease of. African yam bean ... ABSTRACT. Objectives: There has been a dearth of information on the fungal field diseases, which affect the production of ... with other staples such as yam, plantain, cassava, .... The spots were bordered by black margins and light.

  14. Antibacterial activity of various leaf extracts of Merremia emarginata

    Institute of Scientific and Technical Information of China (English)

    EK Elumalai; M Ramachandran; T Thirumalai; P Vinothkumar

    2011-01-01

    Objective: To investigate the antibacterial activity and phytochemical screening of the aqueous, methanol and petroleum ether leaf extracts of Merremia emarginata (M. emarginata). Methods:The antibacterial activity of leaf extracts of M. emarginata were evaluated by agar well diffusion method against four selected bacterial species. Results: The presence of tannins, flavonoids, amino acids, starch, glycosides and carbohydrates in the different leaf extracts was established. The methanol extract was more effective against Bacillus cereus and Escherichia coli, whereas aqueous extract was more effective against Staphylococcus aureus and Pseudomonas aeruginosa.Conclusions: The results in the present study suggest that M. emarginata leaf can be used in treating diseases caused by the tested organisms.

  15. Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

    Science.gov (United States)

    In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

  16. Identification and Classification of Leaf Diseases in Turmeric Plants

    Directory of Open Access Journals (Sweden)

    Nandhini M,

    2016-02-01

    Full Text Available Plant disease identification is the most important sector in agriculture. Turmeric is one of the important rhizomatous crops grown in India. The turmeric leaf is highly exposed to diseases like rhizome rot, leaf spot, and leaf blotch. The identification of plant diseases requires close monitoring and hence this paper adopts technologies to manage turmeric plant diseases caused by fungi to enable production of high quality crop yields. Various image processing and machine learning techniques are used to identify and classify the diseases in turmeric leaf. The dataset with 800 leaf images of different categories were pre-processed and segmented to promote efficient feature extraction. Machine learning algorithms like support vector machine, decision tree and naïve bayes were applied to train the model. The performance of the model was evaluated using 10 fold cross validation and the results are reported.

  17. SpotADAPT

    DEFF Research Database (Denmark)

    Kaulakiene, Dalia; Thomsen, Christian; Pedersen, Torben Bach

    2015-01-01

    Having constantly increasing amounts of data, the analysis of it is often entrusted for a MapReduce framework. The execution of an analytical workload can be cheapened by adopting cloud computing resources, and in particular by using spot instances (cheap, fluctuating price instances) offered by ...

  18. Arc spot grouping: An entanglement of arc spot cells

    Energy Technology Data Exchange (ETDEWEB)

    Kajita, Shin, E-mail: kajita.shin@nagoya-u.jp [EcoTopia Science Institute, Nagoya University, Nagoya 464-8603 (Japan); Hwangbo, Dogyun; Ohno, Noriyasu [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Tsventoukh, Mikhail M. [Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Barengolts, Sergey A. [Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation)

    2014-12-21

    In recent experiments, clear transitions in velocity and trail width of an arc spot initiated on nanostructured tungsten were observed on the boundary of the thick and thin nanostructured layer regions. The velocity of arc spot was significantly decreased on the thick nanostructured region. It was suggested that the grouping decreased the velocity of arc spot. In this study, we try to explain the phenomena using a simple random walk model that has properties of directionality and self-avoidance. And grouping feature was added by installing an attractive force between spot cells with dealing with multi-spots. It was revealed that an entanglement of arc spot cells decreased the spot velocity, and spot cells tend to stamp at the same location many times.

  19. Distribution of white spots after de-bonding in orthodontic patients

    OpenAIRE

    Zabokova-Bilbilova, Efka; Muratovska, Ilijana; Stojanovska, Vera; Stefafanovska, E.; Dimova, Cena

    2014-01-01

    Fixed orthodontic appliances can interfere with removing bacterial plaques from dental surfaces which can ultimately lead to white spot formation. The aim of this study was to evaluate the quantity of white spots lesions in orthodontic patients treated with fixed orthodontic appliances during different treatment periods and to reveal the teeth most commonly affected by white spot lesions. Materials and Methods: A total of 30 patients undergoing or ...

  20. TV spots' impact.

    Science.gov (United States)

    El-bakly, S

    1994-09-01

    The Information, Education and Communication (IEC) Center of the State Information Service was established in 1979 for the purpose of providing information to the people on the population issue. The Ministry of Information has accorded the State Information Service free TV and radio air time for family planning dramas and spots. In the early years information campaigns were organized to make people aware of the population problem by slogans, songs, and cartoons. Around 1984 misconceptions about family planning and contraceptives were attacked through a number of TV and radio spots. A few years later 21 spots on specific contraceptive methods were broadcast which were aired for three years over 3000 times. They were extremely successful. The impact of these TV spots was one of the major reasons why the contraceptive prevalence rate increased from 30% in 1984 to 38% in 1988 and 47% in 1992. Spots were also broadcast about the social implications of large families. The TV soap opera "And The Nile Flows On", with the family planning message interwoven into it, was very well received by the target audience. A program entitled "Wedding of the Month" features couples who know family planning well. The most successful radio program is a 15-20 minute long quiz show for residents of the villages where the Select Villages Project is being implemented. The State Information Service has 60 local information centers in the 26 governorates of Egypt that make plans for the family planning campaign. In 1992 the Minya Initiative, a family planning project was implemented in the Minya Governorate. As a result, the contraceptive prevalence rate rose from 22% to 30% over 18 months. A new project, the Select Village Project, was developed in 1993 that replicates the Minya Initiative on the village level in other governorates. This new project that was implemented in sixteen governorates.

  1. High resolution microarray comparative genomic hybridisation analysis using spotted oligonucleotides.

    NARCIS (Netherlands)

    Carvalho, B; Ouwerkerk, E; Meijer, G.A.; Ylstra, B.

    2004-01-01

    BACKGROUND: Currently, comparative genomic hybridisation array (array CGH) is the method of choice for studying genome wide DNA copy number changes. To date, either amplified representations of bacterial artificial chromosomes (BACs)/phage artificial chromosomes (PACs) or cDNAs have been spotted as

  2. Spilocaea pyracanthae causing leaf scab on loquat in Pakistan

    Directory of Open Access Journals (Sweden)

    Haris Butt

    2015-01-01

    Full Text Available ABSTRACT Loquat is attacked by many phytopathogenic fungi. Among these Spilocaea pyracanthae is of economic importance. The fungus received no attention in Pakistan and some other parts of the world. The current study is focused on the symptomatology of this disease and the etiology of the fungus. During extensive surveys of loquat orchards in 2013 heavy infestations of this disease were observed. The leaf symptoms were observed as olive brown, opaque necrotic sub-circular spots, with light brown coloration in the center. Two or more spots coalesced in severe infections covering large leaf areas. The fungus was identified as Spilocaea pyracanthae on the basis of conidia and morphological characters. The pathogenicity of the fungus was confirmed on healthy plants under greenhouse conditions by following Koch's postulates. The fungus produced characteristic leaf scab symptoms on young leaves. This is the first report of Spilocaea pyracanthae causing leafscab of loquat in Pakistan.

  3. Spilocaea pyracanthae causing leaf scab on loquat in Pakistan

    Directory of Open Access Journals (Sweden)

    Haris Butt

    2016-03-01

    Full Text Available ABSTRACT Loquat is attacked by many phytopathogenic fungi. Among these Spilocaea pyracanthae is of economic importance. The fungus received no attention in Pakistan and some other parts of the world. The current study is focused on the symptomatology of this disease and the etiology of the fungus. During extensive surveys of loquat orchards in 2013 heavy infestations of this disease were observed. The leaf symptoms were observed as olive brown, opaque necrotic sub-circular spots, with light brown coloration in the center. Two or more spots coalesced in severe infections covering large leaf areas. The fungus was identified as Spilocaea pyracanthae on the basis of conidia and morphological characters. The pathogenicity of the fungus was confirmed on healthy plants under greenhouse conditions by following Koch's postulates. The fungus produced characteristic leaf scab symptoms on young leaves. This is the first report of Spilocaea pyracanthae causing leafscab of loquat in Pakistan.

  4. Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data

    Directory of Open Access Journals (Sweden)

    Zhan-yu LIU

    2008-09-01

    Full Text Available Large-scale farming of agriculture crops requires real-time detection of disease for field pest management. Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann. Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy, R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it's at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity.

  5. Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data

    Institute of Scientific and Technical Information of China (English)

    LIU Zhan-yu; HUANG Jing-feng; TAO Rong-xiang

    2008-01-01

    Large-scale farming of agriculture crops requires real-time detection of disease for field pest management.Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann). Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy), R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it's at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity.

  6. Poisson Spot with Magnetic Levitation

    Science.gov (United States)

    Hoover, Matthew; Everhart, Michael; D'Arruda, Jose

    2010-01-01

    In this paper we describe a unique method for obtaining the famous Poisson spot without adding obstacles to the light path, which could interfere with the effect. A Poisson spot is the interference effect from parallel rays of light diffracting around a solid spherical object, creating a bright spot in the center of the shadow.

  7. Great Red Spot (GRS)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    A huge permanent anticyclone in Jupiter's southern hemisphere, visible as a reddish oval at just over 20 °S. The earliest unequivocal observation was by Heinrich Schwabe in 1831 (the often-quoted sighting by Robert Hooke in 1664 now seems to have been of a similar but different spot). The GRS became a striking feature around 1880, when it developed a deep red coloration. It was also prominent in ...

  8. El spot electoral negativo

    Directory of Open Access Journals (Sweden)

    Palma Peña-Jiménez

    2011-01-01

    Full Text Available l spot político tiene durante la campaña un objetivo final inequívoco: la consecución del voto favorable. Se dirige al cuerpo electoral a través de la televisión y de Internet, y presenta, en muchos casos, un planteamiento negativo, albergando mensajes destinados a la crítica frontal contra el adversario, más que a la exposición de propuestas propias. Este artículo se centra en el análisis del spot electoral negativo, en aquellas producciones audiovisuales construidas sin más causa que la reprobación del contrincante. Se trata de vídeos que, lejos de emplearse en difundir las potencialidades de la organización y las virtudes de su candidato –además de su programa electoral–, consumen su tiempo en descalificar al oponente mediante la transmisión de mensajes, muchas veces, ad hominem. Repasamos el planteamiento negativo del spot electoral desde su primera manifestación, que en España data de 1996, año de emisión del conocido como vídeo del dóberman, sin olvidar otros ejemplos que completan el objeto de estudio.

  9. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2014-01-01

    Full Text Available A major security challenge on the Internet is the existence of the large number of compromised machines. Such machines have been increasingly used to launch various security attacks including spamming and spreading malware, DDoS, and identity theft. These compromised machines are called “Zombies”. In general E-mail applications and providers uses spam filters to filter the spam messages. Spam filtering is a technique for discriminating the genuine message from the spam messages. The attackers send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  10. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2015-10-01

    Full Text Available A major security challenge on the Internet is the existence of the large number of compromised machines. Such machines have been increasingly used to launch various security attacks including spamming and spreading malware, DDoS, and identity theft. These compromised machines are called "Zombies". In general E-mail applications and providers uses spam filters to filter the spam messages. Spam filtering is a technique for discriminating the genuine message from the spam messages. The attackers send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  11. Dinâmica temporal da mancha foliar da 'Gala' em macieiras conduzidas sob os sistemas de produção convencional e orgânico Temporal dynamic of 'Gala' leaf spot in apples under conventional and organic production systems

    Directory of Open Access Journals (Sweden)

    Amauri Bogo

    2010-02-01

    Full Text Available Este trabalho objetivou avaliar a dinâmica temporal da Mancha Foliar da 'Gala' em macieira nos sistemas convencional e orgânico de produção, em condições edafo-climáticas do Planalto Catarinense. A incidência e severidade foram quantificadas quinzenalmente, em 100 folhas, distribuídas em quatro ramos da cultivar 'Royal Gala' com 12 repetições, gerando 16 mapas em cada sistema de produção. A severidade foi avaliada de acordo com escala diagramática específica. Com os dados obtidos, foram plotadas curvas de progresso da doença, e as epidemias foram comparadas em relação à a início do aparecimento dos sintomas (IAS; b tempo para atingir a máxima incidência e severidade da doença (TAMID e TAMSD; c valor máximo de incidência e severidade da doença (Imax e Smax; e d área abaixo da curva de progresso da incidência e severidade da doença (AACPID e AACPSD. Os dados de incidência e severidade foram analisados por meio de análise de regressão linear simples, sendo ajustados para três modelos empíricos, Logístico, Monomolecular e Gompertz. A cultivar 'Royal Gala' foi suscetível ao Colletotrichum sp., e as maiores intensidades de doença foram registradas no sistema de produção orgânico. O modelo mais apropriado para descrever o progresso da doença foi o Logístico e, por meio do uso da incidência, não foram detectadas diferenças significativas entre os sistemas de produção, porém a taxa de progresso da severidade da doença foi significativamente maior no sistema de produção orgânico do que no convencional.This study aimed to evaluate the temporal dynamic of 'Gala' leaf spot under conventional and organic systems of production in edafoclimatic conditions of Santa Catarina plateau. The incidence and severity were quantified biweekly in 100 leaves distributed in four branches of the "Royal Gala" cultivar with 12 replications, generating 16 maps for each system of production. The disease severity was evaluated

  12. 环境因素对香蕉叶斑病菌喙突脐蠕孢生长和产孢的影响%Effects of environmental factors on growth and sporulation of Exserohilum rostratum causing banana leaf spot disease

    Institute of Scientific and Technical Information of China (English)

    林善海; 黄思良; 岑贞陆; 覃丽萍; 付岗; 黎起秦

    2013-01-01

    For the purposes of further indepth understanding of the biological characters of Exserohilum rostratum causing banana leaf spots, the influence of partial environmental factors (carbon sources, nitrogen sources and plant extracts) on growth and sporulation of 3 tested isolates (CLER09, D08 and JL05) were investigated. The results indicated that most of the conidia first germinated from the base, and bipolar germinations occurred after 10h of incubation at 28℃. All of the tested isolates showed similar growth reactions on utilizing 20 carbon sources and 26 nitrogen sources. They could utilize all of the tested carbon sources except inulin, and all of the tested nitrogen sources for their vegetative growth and sporulation. The vegetative growth of the isolates were better on 6 tested plant extract media as compared with potato dextrose agar (PDA) medium. All of the tested plant extract media were more suitable for sporulation of isolates CLER09 and JL05 as compared with PDA medium. Except oatmeal agar medium, the other 5 media were more suitable for sporulation of isolate D087 as compared with PDA medium. Conidial morphology was found to be significantly influenced by plant extract media. The conidial lengths of isolates D087 and JL05 markedly extended on rice bran agar and elephant grass agar, while the conidial widths of isolate CLER09 markedly broadened on cornmeal agar medium.%为进一步明确香蕉叶斑病菌喙突脐蠕孢的生物学特性,调查了部分环境因素(碳氮源、植物成分培养基)对供试菌株(CLER09、D087和JL05)的营养生长和产孢的影响.结果显示,分生孢子主要先从基部萌芽,在28℃下约培养10h后出现两端萌芽;供试菌株对测试的20种碳源及26种氮源显示相似的生长反应,均可利用除菊糖外的测试碳源及氮源进行营养生长和产孢;测试的6种植物成分培养基对供试菌株的营养生长效果皆优于PDA培养基;除燕麦培养基外,其余5

  13. Cold spots in neonatal incubators are hot spots for microbial contamination.

    Science.gov (United States)

    de Goffau, Marcus C; Bergman, Klasien A; de Vries, Hendrik J; Meessen, Nico E L; Degener, John E; van Dijl, Jan Maarten; Harmsen, Hermie J M

    2011-12-01

    Thermal stability is essential for the survival and well-being of preterm neonates. This is achieved in neonatal incubators by raising the ambient temperature and humidity to sufficiently high levels. However, potentially pathogenic microorganisms also can thrive in such warm and humid environments. We therefore investigated whether the level of microbial contamination (i.e., the bacterial load) inside neonatal incubators can be predicted on the basis of their average temperature and relative humidity settings, paying special attention to local temperature differences. Swab samples were taken from the warmest and coldest spots found within Caleo incubators, and these were plated to determine the number of microbial CFU per location. In incubators with high average temperature (≥ 34°C) and relative humidity (≥ 60%) values, the level of microbial contamination was significantly higher at cold spots than at hot spots. This relates to the fact that the local equilibrium relative humidity at cold spots is sufficiently high to sustain microbial growth. The abundance of staphylococci, which are the main causative agents of late-onset sepsis in preterm neonates, was found to be elevated significantly in cold areas. These findings can be used to improve basic incubator hygiene.

  14. Modeling leaf venation morphogenesis

    CERN Document Server

    Laguna, M F; Jagla, E A

    2007-01-01

    We explore the possibility that the formation of leaf venation patterns is driven by mechanical instabilities in the growing leaf. In contrast to the prevalent canalization hypothesis based on polar auxin transport, mechanical instabilities lead very naturally to hierarchical patterns with an abundant number of closed loops as they exists in almost every leaf venation. We propose a continuum model where the vein formation is driven by a mechanical collapse of the mesophyll layer in the growing leaf, and present a numerical study of this model using a phase field approach. The results show the same qualitative features as real venation patterns and, furthermore, have the same statistical properties.

  15. Turbulent spots in hypervelocity flow

    Science.gov (United States)

    Jewell, Joseph S.; Leyva, Ivett A.; Shepherd, Joseph E.

    2017-04-01

    The turbulent spot propagation process in boundary layer flows of air, nitrogen, carbon dioxide, and air/carbon dioxide mixtures in thermochemical nonequilibrium at high enthalpy is investigated. Experiments are performed in a hypervelocity reflected shock tunnel with a 5-degree half-angle axisymmetric cone instrumented with flush-mounted fast-response coaxial thermocouples. Time-resolved and spatially demarcated heat transfer traces are used to track the propagation of turbulent bursts within the mean flow, and convection rates at approximately 91, 74, and 63% of the boundary layer edge velocity, respectively, are observed for the leading edge, peak, and trailing edge of the spots. A simple model constructed with these spot propagation parameters is used to infer spot generation rates from observed transition onset to completion distance. Spot generation rates in air and nitrogen are estimated to be approximately twice the spot generation rates in air/carbon dioxide mixtures.

  16. [3] Diseases Caused By Bacterial Pathogens In Inland Water

    OpenAIRE

    若林, 久嗣; 吉田, 照豊; 野村, 哲一; 中井, 敏博; 高野, 倫一

    2016-01-01

    Bacterial diseases cause huge damages in fish farms worldwide, and numerous bacterial pathogens from inland and saline waters have been identified and studied for their characterization, diagnosis, prevention and control. In this chapter, eight important fish diseases viz. 1) streptococcosis (inland water), 2) furunculosis, 3) bacterial gill disease, 4) columnaris disease, 5) bacterial cold-water disease, 6) red spot disease, 7) edwardsiellosis (Edwardsiella ictaluri), and 8) motile aeromonad...

  17. Bacterial Vaginosis

    Science.gov (United States)

    ... Form Controls Cancel Submit Search the CDC Bacterial Vaginosis (BV) Note: Javascript is disabled or is not ... STD on Facebook Sexually Transmitted Diseases (STDs) Bacterial Vaginosis – CDC Fact Sheet Language: English (US) Españ ...

  18. Spotting effect in microarray experiments

    Directory of Open Access Journals (Sweden)

    Mary-Huard Tristan

    2004-05-01

    Full Text Available Abstract Background Microarray data must be normalized because they suffer from multiple biases. We have identified a source of spatial experimental variability that significantly affects data obtained with Cy3/Cy5 spotted glass arrays. It yields a periodic pattern altering both signal (Cy3/Cy5 ratio and intensity across the array. Results Using the variogram, a geostatistical tool, we characterized the observed variability, called here the spotting effect because it most probably arises during steps in the array printing procedure. Conclusions The spotting effect is not appropriately corrected by current normalization methods, even by those addressing spatial variability. Importantly, the spotting effect may alter differential and clustering analysis.

  19. Allozyme gene diversities in some leaf beetles (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Krafsur, E S

    1999-08-01

    Gene diversity at allozyme loci was investigated in the bean leaf beetle, Ceratoma trifurcata Forster; the elm leaf beetle, Xanthogaleruca luteola (Muller); the cottonwood leaf beetle, Chrysomela scripta Fabricus; the western corn rootworm, Diabrotica virgifera virgifera LeConte; the southern corn rootworm, also called the spotted cucumber beetle, D. undecimpunctata howardi Baker; the northern corn rootworm, D. barberi Smith and Lawrence; and the Colorado potato beetle, Leptinotarsa decemlineata (Say). Six of these species are economically important pests of crops and display adaptive traits that may correlate with genetic diversity. Gene diversity H(E) in bean leaf beetles was 17.7 +/- 4.0% among 32 loci. In western corn rootworms, H(E) = 4.8 +/- 2.0% among 36 loci, and in spotted cucumber beetles, H(E) = 11.9 +/- 2.7% among 39 loci. Diversity among 27 loci was 10.5 +/- 4.3% in the Colorado potato beetle. The data were compared with gene diversity estimates from other leaf beetle species in which heterozygosities varied from 0.3 to 21% and no correlation was detected among heterozygosities, geographic ranges, or population densities. Distributions of single-locus heterozygosities were consistent with selective neutrality of alleles.

  20. Characterization of partial resistance to black spot disease of Rosa spp.

    Science.gov (United States)

    Black spot disease (BSD) is one of the most serious diseases of garden roses. Both complete (vertical) resistance and partial (horizontal) resistance have been identified in 16 rose genotypes using two laboratory assays, the detached leaf assay (DLA) and the whole plant inoculation (WPI) approaches...

  1. Using SPOT data for calibrating a wheat growth model under Mediterranean conditions

    NARCIS (Netherlands)

    Clevers, J.G.P.W.; Vonder, O.W.; Jongschaap, R.E.E.; Desprats, J.F.; King, C.; Prévot, L.; Bruguier, N.

    2002-01-01

    This paper describes the use of SPOT satellite data for deriving crop biophysical parameters at various dates during the growing season. In particular, the leaf area index (LAI) was estimated by using the semi-empirical CLAIR model. Subsequently, these LAI estimates were used for calibrating the mec

  2. Bacterial Vaginosis

    Science.gov (United States)

    ... Issues > Conditions > Sexually Transmitted > Bacterial Vaginosis Health Issues Listen Español Text Size Email Print Share Bacterial Vaginosis Page Content Bacterial vaginosis (BV) is the most common vaginal infection in sexually active teenaged girls . It appears to be caused by ...

  3. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  4. Leaf Size in Swietenia

    Science.gov (United States)

    Charles B. Briscoe; F. Bruce. Lamb

    1962-01-01

    A study was made of the putative hybrid of bigleaf and small-leaf mahoganies. Initial measurements indicated that bigleaf mahogany can be distinguished from small-leaf mahogany by gross measurements of leaflets. Isolated mother trees yield typical progeny. Typical mother trees in mixed stands yield like progeny plus, usually, mediumleaf progeny. Mediumleaf mother trees...

  5. Root bacterial endophytes alter plant phenotype, but not physiology

    DEFF Research Database (Denmark)

    Henning, Jeremiah A.; Weston, David J.; Pelletier, Dale A.;

    2016-01-01

    (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf...

  6. The SPOT satellite

    Science.gov (United States)

    Fouquet, J.-P.

    1981-03-01

    The background, objectives and data products of the French SPOT remote sensing satellite system are presented. The system, which was developed starting in 1978 with the subsequent participation of Sweden and Belgium, is based on a standard multimission platform with associated ground control station and a mission-specific payload, which includes two High-Resolution Visible range instruments allowing the acquisition of stereoscopic views from different orbits. Mission objectives include the definition of future remote sensing systems, the compilation of a cartographic and resources data base, the study of species discrimination and production forecasting based on frequent access and off-nadir viewing, the compilation of a stereoscopic data base, and platform and instrument qualification, for possible applications in cartography, geology and agriculture. Standard data products will be available at three levels of preprocessing: radiometric correction only, precision processing for vertical viewing, and cartographic quality processing.

  7. Bacterial Sialidase

    Science.gov (United States)

    2004-01-01

    Data shows that elevated sialidase in bacterial vaginosis patients correlates to premature births in women. Bacterial sialidase also plays a significant role in the unusual colonization of Pseudomonas aeruginosa in cystic fibrosis patients. Crystals of Salmonella sialidase have been reproduced and are used for studying the inhibitor-enzyme complexes. These inhibitors may also be used to inhibit a trans-sialidase of Trypanosome cruzi, a very similar enzyme to bacterial sialidase, therefore preventing T. cruzi infection, the causitive agent of Chagas' disease. The Center for Macromolecular Crystallography suggests that inhibitors of bacterial sialidases can be used as prophylactic drugs to prevent bacterial infections in these critical cases.

  8. Bactericidal activity of black pepper, bay leaf, aniseed and coriander against oral isolates.

    Science.gov (United States)

    Chaudhry, Nazia Masood Ahmed; Tariq, Perween

    2006-07-01

    Present investigation focused on antibacterial potential of aqueous decoction of black pepper (Piper nigrum L.), bay leaf (Laurus nobilis L.), aniseed (Pimpinella anisum L.), and coriander (Coriandum sativum L.) against 176 bacterial isolates belonging to 12 different genera of bacterial population isolated from oral cavity of 200 individuals. The disc diffusion technique was employed. Overall aqueous decoction of black pepper was the most bacterial-toxic exhibited 75% antibacterial activity as compared to aqueous decoction of bay leaf (53.4%) and aqueous decoction of aniseed (18.1%), at the concentration of 10 ml/disc. The aqueous decoction of coriander did not show any antibacterial effect against tested bacterial isolates.

  9. Justifications Shape Ethical Blind Spots

    NARCIS (Netherlands)

    Pittarello, Andrea; Leib, Margarita; Gordon-Hecker, Tom; Shalvi, Shaul

    2015-01-01

    To some extent, unethical behavior results from people's limited attention to ethical considerations, which results in an ethical blind spot. Here, we focus on the role of ambiguity in shaping people's ethical blind spots, which in turn lead to their ethical failures. We suggest that in ambiguous se

  10. Divide and conquer spot noise

    NARCIS (Netherlands)

    Leeuw, W.C. de; Liere, R. van

    1997-01-01

    The design and implementation of an interactive spot noise algorithm is presented. Spot noise is a technique which utilizes texture for the visualization of flow fields. Various design tradeoffs are discussed that allow an optimal implementation on a range of high end graphical workstations. Two app

  11. Black-spot poison ivy.

    Science.gov (United States)

    Schram, Sarah E; Willey, Andrea; Lee, Peter K; Bohjanen, Kimberly A; Warshaw, Erin M

    2008-01-01

    In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most common cause of allergic contact dermatitis in the United States, black-spot poison ivy dermatitis is relatively rare.

  12. ANTIBACTERIAL ACTIVITY OF DIFFERENT EXTRACT OF MORINGA OLEIFERA LEAF AGAINST SOME PATHOGENIC BACTERIA

    OpenAIRE

    Santosh Kumar Singh

    2013-01-01

    Leaf extracts of Moringa oleifera (aqueous, hexane, ethanol and methanol) were investigated for antibacterial activity and found effective against all tested strains. However leaf extracted in methanol was more effective followed by ethanol, aqueous and hexane. Methanol extract of leaf showed maximum activity against the tested bacterial strains and MIC was 2, 3 and 3 mg/ml for Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli respectively. Therefore this can be selected for ...

  13. ANTIBACTERIAL ACTIVITY OF DIFFERENT EXTRACT OF MORINGA OLEIFERA LEAF AGAINST SOME PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Singh

    2013-04-01

    Full Text Available Leaf extracts of Moringa oleifera (aqueous, hexane, ethanol and methanol were investigated for antibacterial activity and found effective against all tested strains. However leaf extracted in methanol was more effective followed by ethanol, aqueous and hexane. Methanol extract of leaf showed maximum activity against the tested bacterial strains and MIC was 2, 3 and 3 mg/ml for Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli respectively. Therefore this can be selected for further investigation to determine its therapeutic potential.

  14. Genome Sequence of a Xylella fastidiosa Strain Causing Sycamore Leaf Scorch Disease in Virginia.

    Science.gov (United States)

    Guan, Wei; Shao, Jonathan; Davis, Robert E; Zhao, Tingchang; Huang, Qi

    2014-08-21

    Xylella fastidiosa causes bacterial leaf scorch in landscape trees including sycamore. We determined the draft genome of X. fastidiosa strain Sy-Va, isolated in Virginia from a sycamore tree displaying leaf scorch symptoms. The Sy-VA genome contains 2,477,829 bp, and has a G+C content of 51.64 mol%.

  15. Distribution of White Spots after Debanding in Orthodontic Patients

    Directory of Open Access Journals (Sweden)

    F. Arbabzadeh Zavareh

    2006-12-01

    Full Text Available Statement of problem: Fixed orthodontic appliances can interfere with removing bacterial plaques from dental surfaces which can ultimately lead to white spot formation.Purpose: The aim of this study was to evaluate the quantity of white spots and areas of decalcification following fixed orthodontic treatment.Materials and Methods: A total of 100 patients undergoing or scheduled for fixed orthodontic treatment were divided into two groups. Group A consisted of fifty volunteers before the initiation of therapy and group B included fifty patients at the end of their treatment. In group A, the buccal surfaces of the first molars in each quadrant were examined for the presence of enamel decalcifications. After removing the orthodontic bands in group B, the buccal surfaces of the first molars in each quadrant were examined for white spots. Gender, oral hygiene level, plaque index, type of cement and duration of treatment were recorded for all patients. Binomial logistic regression, chi-square and Mann-Whitney U-tests were used for statistical analysis.Results: The number of white spots in group A was 28 (14% which was significantly lower than group B with 83 (41.5% decalcified lesions (P<0.01. Oral hygiene and duration of treatment had a significant effect on the occurrence of white spots (P<0.05.Conclusion: The results showed that patients with orthodontic bands are at higher risk for white spot formation and good oral hygiene demonstrates a protective effect on their reduction. Both professional and daily oral hygiene measures can decrease thecariogenicity of bacterial plaques in these patients.

  16. Pattern Formation in a Bacterial Colony Model

    Directory of Open Access Journals (Sweden)

    Xinze Lian

    2014-01-01

    Full Text Available We investigate the spatiotemporal dynamics of a bacterial colony model. Based on the stability analysis, we derive the conditions for Hopf and Turing bifurcations. Furthermore, we present novel numerical evidence of time evolution of patterns controlled by parameters in the model and find that the model dynamics exhibit a diffusion controlled formation growth to spots, holes and stripes pattern replication, which show that the bacterial colony model is useful in revealing the spatial predation dynamics in the real world.

  17. Seleção de progênies de Coffea arabica com resistência simultânea à mancha aureolada e à ferrugem alaranjada Selection of progenies of Coffea arabica with simultaneous resistance to bacterial blight and leaf rust

    Directory of Open Access Journals (Sweden)

    Marcos Rafael Petek

    2006-01-01

    Full Text Available O objetivo desta investigação foi estudar progênies de Coffea arabica quanto a resistência à ferrugem alaranjada, causada por Hemileia vastatrix, e à mancha aureolada, causada por Pseudomonas syringae pv. garcae. O experimento foi instalado no Centro de Produção e Experimentação de Londrina, do Instituto Agronômico do Paraná. Utilizou-se delineamento em blocos ao acaso, com três repetições, 13 tratamentos (11 progênies e as testemunhas 'IAPAR 59' e 'Catuaí Vermelho IAC 81'. Os resultados sugerem investigar a possibilidade da ocorrência de novo(s patotipo(s de P. syringae pv. garcae no Paraná. Observou-se na cultivar 'IAPAR 59' resistência suficiente para reduzir danos provocados por P. syringae pv. garcae, causador da mancha aureolada, em regiões de alta ocorrência do patógeno no Paraná. Na progênie "Catuaí" x "Icatú" PRFB 2-27-1/F5 (IAPAR 96095 verificou-se resistência simultânea à ferrugem alaranjada e à mancha aureolada e deverá ser testada em ensaios regionais.This research aimed at to study C. arabica progenies as to resistances to bacterial blight "mancha aureolada", caused by Pseudomonas syringae pv. garcae, and coffee leaf rust, caused by Hemileia vastatrix. The experiment was carried out in the Centro de Produção e Experimentação de Londrina, Instituto Agronômico do Paraná. It was set in a randomized complete block design with 13 treatments (11 progenies and the controls 'IAPAR 59' and 'Catuaí Vermelho IAC 81' and three replications. The results suggest the ocurrence of new(s pathotype(s of P. syringae pv. garcae in Paraná State. The IAPAR 59 cultivar is an option to minimize the damage caused by P. syringae pv. garcae in areas of high incidence of this pathogen. The progeny PRFB 2-27-1/F5 (IAPAR 96095 from "Catuaí" x "Icatú" cross presented simultaneous resistance to leaf rust and to bacterial blight ("mancha aureolada". It will be tested in future regional trials.

  18. Leaf growth is conformal

    CERN Document Server

    Alim, Karen; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  19. Leaf growth is conformal

    Science.gov (United States)

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I.; Boudaoud, Arezki

    2016-10-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  20. Antimicrobial activity of medicinal plant leaf extracts against pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Atikya Farjana

    2014-09-01

    Full Text Available Objective: To determine antibacterial activity of water, oil and methanol extracts of guava (Psidium guajava, green tea (Camellia sinensis, neem (Azadirachta indica and marigold (Calendula officinalis against different species of bacteria, Pseudomonas spp., Vibrio cholerae, Vibrio parahaemolyticus (V. parahaemolyticus, Klebsiella spp., Escherichia coli, Salmonella spp. and Staphylococcus aureus (S. aureus. Methods: Antibacterial activity of plant extracts was measured by agar well diffusion method. Results: Boiled water extracts of guava leaf showed the largest zone of inhibition (22 mm against V. parahaemolyticus. Water extracts of green tea leaf at boiling and room temperature showed 17.5 mm and 19 mm zone of inhibitions against V. parahaemolyticus and S. aureus, respectively. Boiled water extract of neem leaf showed moderate zone of inhibition against Escherichia coli (10 mm and Klebsiella spp. (11 mm. Water and oil extracts of marigold leaf at both boiling and room temperature did not show any zone of inhibition against any of the tested microorganisms. Methanol extracts of both guava and green tea leaves showed same zone of inhibition against Pseudomonus spp. (18 mm. Methanol extract of neem leaf showed antibacterial acitivity against Klebsiella spp. (16 mm and Vibrio cholerae (14 mm and that of marigold leaf showed antimicrobial activity against S. aureus (18 mm and Klebsiella spp. (12 mm. Conclusions: The results from the study suggest that the leaves of guava, green tea, neem and marigold show anibacterial activity against different bacterial species. They could be used as alternatives to common antimicrobial agents for treatment of bacterial infections.

  1. Antimicrobial activity of seed, pomace and leaf extracts of sea ...

    African Journals Online (AJOL)

    Antimicrobial activity of seed, pomace and leaf extracts of sea buckthorn ( Hippophae rhamnoides L.) against foodborne and food spoilage pathogens. ... Bacterial enumeration was significantly reduced by 0.15 to 0.31, 0.26 to 1.72 and 0.59 to ...

  2. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  3. Remote sensing based mapping of leaf nitrogen and leaf area index in European landscapes using the REGularized canopy reFLECtance (REGFLEC) model

    DEFF Research Database (Denmark)

    Boegh, E.; Houborg, R.; Bienkowski, J.

    2011-01-01

    index (LAI) are important determinants of the maximum CO2 Methods/Approach uptake by plants and trees. In the EU project NitroEurope, high spatial resolution (10-20 m) remote sensing data from the HRG and HRVIR sensors onboard the SPOT satellites were acquired to derive maps of leaf N and LAI for 5...

  4. Neglected bacterial zoonoses.

    Science.gov (United States)

    Chikeka, I; Dumler, J S

    2015-05-01

    Bacterial zoonoses comprise a group of diseases in humans or animals acquired by direct contact with or by oral consumption of contaminated animal materials, or via arthropod vectors. Among neglected infections, bacterial zoonoses are among the most neglected given emerging data on incidence and prevalence as causes of acute febrile illness, even in areas where recognized neglected tropical diseases occur frequently. Although many other bacterial infections could also be considered in this neglected category, five distinct infections stand out because they are globally distributed, are acute febrile diseases, have high rates of morbidity and case fatality, and are reported as commonly as malaria, typhoid or dengue virus infections in carefully designed studies in which broad-spectrum diagnoses are actively sought. This review will focus attention on leptospirosis, relapsing fever borreliosis and rickettsioses, including scrub typhus, murine typhus and spotted fever group rickettsiosis. Of greatest interest is the lack of distinguishing clinical features among these infections when in humans, which confounds diagnosis where laboratory confirmation is lacking, and in regions where clinical diagnosis is often attributed to one of several perceived more common threats. As diseases such as malaria come under improved control, the real impact of these common and under-recognized infections will become evident, as will the requirement for the strategies and allocation of resources for their control.

  5. 木薯叶片愈伤组织对枯萎病病原菌的抗性筛选%Screening for Cassava Leaf Callus Resistance to Bacterial Wilt

    Institute of Scientific and Technical Information of China (English)

    陆荣生; 韩美丽; 霍秀娟; 马跃峰

    2012-01-01

    以木薯品种“GR911”、“面包木薯”试管苗叶片为材料,研究木薯枯萎病病原菌粗提物对愈伤组织增殖与分化的影响.以期建立枯萎病病原菌粗提物为选择压力的木薯离体抗病筛选体系。结果表明:所用品种幼叶愈伤诱导与增殖的适宜配方为改良的MS培养基+0.5-0.75mg/L2,4一D:愈伤分化适宜配方为的MS培养基+O.75—1.0mg/LZT。“GR911”与“面包木薯”愈伤增殖过程中。愈伤褐化率达到50%所需的细菌液粗提物浓度分别为5.5×、2.5×^6cfu/mE:愈伤组织分化过程中,愈伤褐化率达到50%所需的菌液粗提物浓度分别为7.0×10^6、4.0×10^6cfu/mL。通过建立木薯愈伤组织离体抗病筛选体系。为木薯无性系变异育种奠定基础。%This study was made to clarify the effects of bacterial crude toxin culture on proliferation and differentiation of callus in cassava, to screen system of resistance to bacterial wilt caused by Xanthomonas manihotis (Artheodet Bey.) Stars in vitro. The young leaves from plantlet were used as explants. On basal modified MS medium, the optimum hormone concentration is 0.5-0.75 mg/L 2 ,4-D for induction and proliferation of callus, and 0.75-1.0 mg/ L ZT for differentiation of callus. To achieve 50 % callus browning rate during callus proliferation, the concentration of bacteria crude toxin culture in medium should be 5.5×106 cfu/ml for species GR991 and 2.5× 106 cfu/ml for species MianBao. To get 50 % callus browning rate during callus differentiation, the concentration of bacteria crude toxin culture in medi-um should be 7.0×106 cfu/ml for species GR991 and 4.0× 106 cfu/ml for species MianBao. By this ex- periment, the screening system of resistance to bacterial wilt was established in vitro in cassava, and this system can be used for clone breeding studies.

  6. Coulomb explosion of "hot spot"

    CERN Document Server

    Oreshkin, V I; Chaikovsky, S A; Artyomov, A P

    2016-01-01

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed and estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  7. Final report on the safety assessment of AloeAndongensis Extract, Aloe Andongensis Leaf Juice,aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice,aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract.

    Science.gov (United States)

    2007-01-01

    Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow latex containing a number of anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for cathartic effects. The gel contains polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%. Oral administration of various anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces; polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and antiviral activities, and has been effective in wound healing and infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic

  8. Root bacterial endophytes alter plant phenotype, but not physiology

    DEFF Research Database (Denmark)

    Henning, Jeremiah A.; Weston, David J.; Pelletier, Dale A.

    2016-01-01

    Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant...... phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits...... (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf...

  9. Production of polyclonal antiserum specific to the 27.5 kDa envelope protein of white spot syndrome virus

    NARCIS (Netherlands)

    You, Z.O.; Nadala, E.C.B.; Yang, J.S.; Hulten, van M.C.W.; Loh, P.C.

    2002-01-01

    A truncated version of the white spot syndrome virus (WSSV) 27.5 kDa envelope protein was expressed as a histidine tag fusion protein in Escherichia coli. The bacterial expression system allowed the production of up to 10 mg of purified recombinant protein per liter of bacterial culture. Antiserum f

  10. Production of polyclonal antiserum specific to the 27.5 kDa envelope protein of white spot syndrome virus

    NARCIS (Netherlands)

    You, Z.O.; Nadala, E.C.B.; Yang, J.S.; Hulten, van M.C.W.; Loh, P.C.

    2002-01-01

    A truncated version of the white spot syndrome virus (WSSV) 27.5 kDa envelope protein was expressed as a histidine tag fusion protein in Escherichia coli. The bacterial expression system allowed the production of up to 10 mg of purified recombinant protein per liter of bacterial culture. Antiserum f

  11. Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-05-01

    Full Text Available Systemic acquired resistance (SAR is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields.

  12. Two volatile organic compounds trigger plant self-defense against a bacterial pathogen and a sucking insect in cucumber under open field conditions.

    Science.gov (United States)

    Song, Geun Cheol; Ryu, Choong-Min

    2013-05-08

    Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields.

  13. Significant yield increases from control of leaf diseases in maize - an overlooked problem?!

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup

    2012-01-01

    The area of maize has increased in several European countries in recent years. In Denmark, the area has increased from 10,000 ha in 1980 to 185,000 ha in 2011. Initially only silage maize was cultivated in Denmark, but in more recent years the area of grain maize has also increased. Farms growing...... maize have often grown maize consecutively for several years. This leads to significant amounts of debris building up in the fields, which serves as an important source of inoculum for diseases when new crops are grown. In recent years, leaf diseases have caused production problems over several seasons....... Two major diseases have been identified: Eyespot (Kabatiella zeae) and Northern leaf blotch (Exserohilum turcicum). Other diseases, including Southern maize leaf blight or maydis leaf blight, caused by Bipolaris maydis, and Northern corn leaf spot, caused by Bipolaris zeicola, may potentially play...

  14. Bacterial gastroenteritis

    Science.gov (United States)

    ... most common types of bacterial gastroenteritis in a couple of days. The goal is to make you feel better and avoid dehydration. Drinking enough fluids and learning what to eat will help ease symptoms. You ...

  15. Bacterial vaginosis

    National Research Council Canada - National Science Library

    Islam, Aliya; Safdar, Anjum; Malik, Ayesha

    2009-01-01

    To estimate the frequency of bacterial vaginosis in women with preterm labour. Descriptive cross sectional study carried out in department of Obstetrics and Gynaecology, Military Hospital and Army Medical College Laboratory, Rawalpindi...

  16. Identification of Alfalfa Leaf Diseases Using Image Recognition Technology

    Science.gov (United States)

    Qin, Feng; Liu, Dongxia; Sun, Bingda; Ruan, Liu; Ma, Zhanhong; Wang, Haiguang

    2016-01-01

    Common leaf spot (caused by Pseudopeziza medicaginis), rust (caused by Uromyces striatus), Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana) and Cercospora leaf spot (caused by Cercospora medicaginis) are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering) and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis). After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection), disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM) and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features) was the optimal model. For this SVM model, the

  17. ASSESSMENT OF BIOTHERAPEUTIC POTENTIAL OF PIMENTA DIOICA (ALLSPICE LEAF EXTRACT

    Directory of Open Access Journals (Sweden)

    Dr Pratima Khandelwal et al

    2012-09-01

    Full Text Available All-spice (pimenta is one of the under-utilized resources available in the tropical regions of the globe. It is a variety of sweet pepper used as a spice and its leaves are used for traditional culinary purpose. Researchers have studied the antioxidant potentials of the berries of the plant, but no documented work is reported on its stem, leaf and roots for antimicrobial properties. Thus, the present investigation was carried out to access the antimicrobial and anti-oxidation potentials of leaf extracts using three solvent systems, (Aqueous, acetone and methanol. All solvent systems at different concentrations were evaluated for antibacterial, antifungal and reducing capacity against selected bacterial and fungal pathogens; zone of inhibition was exhibited by methanol leaf extracts in decreasing order for Escherichia coli, Bacillus cereus, Salmonella typhimurium, and Staphylococcus aureus. Lesser inhibitory zones were obtained by acetone leaf extracts, whereas, Klebsiella pneumonia and Pseudomonas aeruginosa were not inhibited by any extracts. Aqueous extract demonstrated no inhibitory activity against tested bacterial pathogens. All the three leaf extracts were found to be ineffective against fungal strains (Fusarium oxysporum, Aspergillus niger, Aspergillus flavus and Candida albicans tested. Protein content in each extract was determined and reducing capability was estimated which was found to be high in methanol and acetone extract whereas aqueous extract showed low reducing ability.

  18. Comparative leaf proteomics of drought-tolerant and -susceptible peanut in response to water stress

    DEFF Research Database (Denmark)

    Katam, Ramesh; Sakata, Katsumi; Suravajhala, Prashanth;

    2016-01-01

    drought tolerance characteristics were subjected to WS, and their leaf proteome was compared using two-dimensional electrophoresis complemented with MALDI-TOF/TOF mass spectrometry. Ninety-six protein spots were differentially abundant to water stress in both cultivars that corresponded to 60 non...

  19. Laser based spot weld characterization

    Science.gov (United States)

    Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

    2016-02-01

    Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

  20. Leaf anatomy and photosynthesis

    NARCIS (Netherlands)

    Berghuijs, H.N.C.

    2016-01-01

    Keywords: CO2 diffusion, C3 photosynthesis, mesophyll conductance, mesophyll resistance, re-assimilation, photorespiration, respiration, tomato Herman Nicolaas Cornelis Berghuijs (2016). Leaf anatomy and photosynthesis; unravelling the CO2 diffusion pathway in C3 leaves. PhD thesis. Wageningen Unive

  1. Is this Red Spot the Blue Spot (locus ceruleum)?

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Won Sick; Lee, Yu Kyung; Lee, Min Kyung; Hwang, Kyung Hoon [Gachon University Gil Hospital, Incheon (Korea, Republic of)

    2010-06-15

    The authors report brain images of 18F-FDG-PET in a case of schizophrenia. The images showed strikingly increased bilateral uptake in the locus ceruleum. The locus ceruleum is called the blue spot and known to be a center of the norepinephrinergic system.

  2. Bacterial diseases of tomato plants in terms of open and covered growing of Ukraine

    Directory of Open Access Journals (Sweden)

    J.V. Kolomiets

    2017-06-01

    Full Text Available It was established that the main causes of mass diseases of tomato in covered ground in Ukraine are agents of bacterial black spotting, bacterial speck and in open ground are agent of bacterial cancer of tomato plants. Typical symptoms of diseases are wilting and die-off of young plants, blackening of fiber vascular bundles, black spotting of leaves and fruits, and fruit stem rot. It was studied morphological and cultural, as well as physiological and biochemical properties of the selected strains of the agents of tomato bacterial diseases. We recommended biological preparations Phytocide and Phytohelp based on the bacteria Bacillus subtilis, to restrict the development of the agents of bacterial black spotting Xanthomonas vesicatoria and bacterial cancer Clavibacter michiganensis subsp. michiganensis.

  3. Separation and identification of Musa acuminate Colla (banana) leaf proteins by two-dimensional gel electrophoresis and mass spectrometry.

    Science.gov (United States)

    Lu, Y; Qi, Y X; Zhang, H; Zhang, H Q; Pu, J J; Xie, Y X

    2013-12-19

    To establish a proteomic reference map of Musa acuminate Colla (banana) leaf, we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Tryptic digests of 44 spots were subjected to peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. Three spots that were not identified by MALDI-TOF MS analysis were identified by searching against the NCBInr, SwissProt, and expressed sequence tag (EST) databases. We identified 41 unique proteins. The majority of the identified leaf proteins were found to be involved in energy metabolism. The results indicate that 2D-PAGE is a sensitive and powerful technique for the separation and identification of Musa leaf proteins. A summary of the identified proteins and their putative functions is discussed.

  4. 海南省芒果细菌性黑斑病原菌生理生化特性初步研究%Preliminary Study on Physiological and Biochemical Features of the Pathogen of Mango Bacterial Black Spot in Hainan Province

    Institute of Scientific and Technical Information of China (English)

    漆艳香; 谢艺贤; 张贺; 张欣; 陆英; 喻群芳; 蒲金基

    2014-01-01

    In order to understand the physiological and biochemical features of Xanthomonas campestris pv. mangiferaeindicae and provide theoretical basis for scientific control of mango bacterial black spot, thirteen physiological and seven biochemical indexes of twelve Xanthomonas campestris pv. mangiferaeindicae strains from four cities (or counties) of Hainan Province were identified in this study. The results showed that nine out of thirteen physiological features were identical, including NaCl tolerance, pH tolerance, tween-80, acetate, sucrose, galactose, lactose, maltose and mannite, while the utilization of fructose, glucose, rhamnose and xylose was obviously different. Among seven tested biochemical features, oxidase, catalase, and amylase reaction, nitrate reduction, starch hydrolysis and gelatin hydrolysis were identical except H2S. Jaccard’s genetic similarity coefficients were calculated and dendrograms were constructed by the unweighted pair group method of arithmetic average (UPGMA) using the NTSYS-pc version 2.10. Different cluster analysis of physiological and biochemical tests indicated that strains from different cities or counties could share the same class, which showed that there were some diversities among Xanthomonas campestris pv. mangiferaeindicae in Hainan Province.%为了明确海南省芒果细菌性黑斑病原菌的生理生化特性,为该病害的科学防治提供理论基础。从海南省4县市分离获得12株芒果细菌性黑斑病原菌(Xanthomonas campestris pv. mangiferaeindicae)菌株并对其进行13项生理和7项生化特性测定。结果表明,在所测试的13项生理特征中有9项[耐盐性(1%~3%)、pH(5.0~8.0)、吐温80、醋酸盐、蔗糖、α-半乳糖、乳糖、麦芽糖和甘露醇]反应结果完全相同,但对果糖、葡萄糖、鼠李糖和木糖等碳源的利用却有明显差异。在7项生化试验项目中,除HNMG15产H2S试验为阴性外,其余供试菌株的氧化酶、过

  5. The puzzling MILAGRO hot spots

    CERN Document Server

    Drury, Luke

    2008-01-01

    We discuss the reported detection by the MILAGRO experiment of localised hot spots in the cosmic ray arrival distribution and the difficulty of interpreting these observations. A model based on secondary neutron production in the heliotail is shown to fail. An alternative model based on loss-cone leakage through a magnetic trap from a local source region is proposed.

  6. Early detection of sugar beet pathogen Ramularia beticola in leaf and air samples using qPCR

    DEFF Research Database (Denmark)

    Wieczorek, Thies Marten; Jørgensen, Lise Nistrup; Hansen, Anne Lisbet

    2014-01-01

    A quantitative PCR method (qPCR) was developed for the detection and quantification of Ramularia beticola causing Ramularia leaf spot in sugar beet. R. beticola specific primers were designed based on the internal transcribed spacer region 2 (ITS2). The assay was applied on DNA extracted from...... also tested with the qPCR assay. It was possible to detect the presence of R. beticola in the leaves pre-symptomatic at least 10 days before the occurrence of the visible symptoms of Ramularia leaf spot. This is the first report of a molecular assay, which allows screening for the presence of R...

  7. DNA Fingerprinting of Mycobacterium tuberculosis Complex Culture Isolates Collected in Brazil and Spotted onto Filter Paper

    OpenAIRE

    Burger,Marion; Raskin, Salmo; Brockelt, Sonia R.; Amthor, Beate; Geiss, Heinrich K.; Haas, Walter H.

    1998-01-01

    The usefulness of filter paper for preservation of bacterial cells was shown by mixed-linker DNA fingerprint analysis of Mycobacterium tuberculosis isolates from 77 Brazilian patients. DNA fingerprints of samples spotted onto filter paper and conventional culture material were identical. Thus, filter paper specimens analyzed by an amplification-based typing method provide a new resource for epidemiological studies of infectious diseases.

  8. DNA fingerprinting of Mycobacterium tuberculosis complex culture isolates collected in Brazil and spotted onto filter paper.

    Science.gov (United States)

    Burger, M; Raskin, S; Brockelt, S R; Amthor, B; Geiss, H K; Haas, W H

    1998-02-01

    The usefulness of filter paper for preservation of bacterial cells was shown by mixed-linker DNA fingerprint analysis of Mycobacterium tuberculosis isolates from 77 Brazilian patients. DNA fingerprints of samples spotted onto filter paper and conventional culture material were identical. Thus, filter paper specimens analyzed by an amplification-based typing method provide a new resource for epidemiological studies of infectious diseases.

  9. Arabidopsis onset of leaf death mutants identify a regulatory pathway controlling leaf senescence

    NARCIS (Netherlands)

    Jing, Hai-Chun; Sturre, Marcel J.G.; Hille, Jacques; Dijkwel, Paul P.

    2002-01-01

    The onset of leaf senescence is controlled by leaf age and ethylene can promote leaf senescence within a specific age window. We exploited the interaction between leaf age and ethylene and isolated mutants with altered leaf senescence that are named as onset of leaf death (old) mutants. Early leaf

  10. Bacterial Ecology

    DEFF Research Database (Denmark)

    Fenchel, Tom

    2011-01-01

    Bacterial ecology is concerned with the interactions between bacteria and their biological and nonbiological environments and with the role of bacteria in biogeochemical element cycling. Many fundamental properties of bacteria are consequences of their small size. Thus, they can efficiently exploit...

  11. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    1994-01-01

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation, mea

  12. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  13. SPOT- 4 North American Data Buy

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS has contracted with SPOT Image Corporation to acquire and provide Satellite Pour l'Observation de la Terre (SPOT) satellite data for calendar years 2010 and...

  14. SPOT 5 North American Data Buy

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS has contracted with SPOT Image Corporation to acquire and provide Satellite Pour l'Observation de la Terre (SPOT) satellite data for calendar years 2010 and...

  15. Rocky Mountain Spotted Fever: Statistics and Epidemiology

    Science.gov (United States)

    ... The CDC Cancel Submit Search The CDC Rocky Mountain Spotted Fever (RMSF) Note: Javascript is disabled or ... please visit this page: About CDC.gov . Rocky Mountain Spotted Fever (RMSF) Symptoms, Diagnosis, and Treatment Statistics ...

  16. SPOT- 5 North American Data Buy

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS has contracted with SPOT Image Corporation to acquire and provide Satellite Pour l'Observation de la Terre (SPOT) satellite data for calendar years 2010 and...

  17. SPOT 4 North American Data Buy

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS has contracted with SPOT Image Corporation to acquire and provide Satellite Pour l'Observation de la Terre (SPOT) satellite data for calendar years 2010 and...

  18. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  19. Leaf anatomy and photosynthesis

    OpenAIRE

    Berghuijs, H.N.C.

    2016-01-01

    Keywords: CO2 diffusion, C3 photosynthesis, mesophyll conductance, mesophyll resistance, re-assimilation, photorespiration, respiration, tomato Herman Nicolaas Cornelis Berghuijs (2016). Leaf anatomy and photosynthesis; unravelling the CO2 diffusion pathway in C3 leaves. PhD thesis. Wageningen University, Wageningen, The Netherlands, with summaries in English and Dutch. 286 pages Optimizing photosynthesis can contribute to improving crop yield, which is necessary to meet the increasing global...

  20. Spectrum-specific damage and solar ultraviolet radiation avoidance in the two-spotted spider mite.

    Science.gov (United States)

    Sakai, Yuta; Osakabe, Masahiro

    2010-01-01

    The spatial distribution of the two-spotted spider mite Tetranychus urticae Koch is biased toward the lower surfaces of leaves as compared with the upper leaf surfaces on their host plants. Because of the deleterious effects of solar ultraviolet (UV) irradiation, we hypothesized T. urticae remains on lower leaf surfaces as an adaptation to avoid solar UV radiation (UVR). We examined the effects of solar UVR components on females and tested whether spatial distribution was associated with solar UVR avoidance. Attenuation of solar UVR using UV opaque film increased fecundity and reduced the movement of females from the upper to the lower leaf surfaces. In contrast, diverting solar UVR to the lower leaf surface using a light reflection sheet caused the mites to move from the lower to the upper leaf surfaces; however, attenuated UV reflection did not, suggesting that they occupy the lower leaf surface to avoid solar UVR. In monochromatic UVR tests, no eggs hatched when placed under 280-300 nm radiation, whereas almost all eggs hatched at 320-360 nm. Adult females, however, did not avoid wavelengths of 280 and 300 nm, but avoided 320-340 nm. We conclude that T. urticae exploit UVA information to avoid ambient UVB radiation.

  1. Improvements on analytic modelling of stellar spots

    CERN Document Server

    Montalto, M; Oshagh, M; Boisse, I; Bruno, G; Santos, N C

    2014-01-01

    In this work we present the solution of the stellar spot problem using the Kelvin-Stokes theorem. Our result is applicable for any given location and dimension of the spots on the stellar surface. We present explicitely the result up to the second degree in the limb darkening law. This technique can be used to calculate very efficiently mutual photometric effects produced by eclipsing bodies occulting stellar spots and to construct complex spot shapes.

  2. 9 CFR 149.4 - Spot audit.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Spot audit. 149.4 Section 149.4... LIVESTOCK IMPROVEMENT VOLUNTARY TRICHINAE CERTIFICATION PROGRAM § 149.4 Spot audit. (a) In addition to regularly scheduled site audits, certified production sites will be subject to spot audits. (1) Random...

  3. Delivering high-resolution landmarks using inkjet micropatterning for spatial monitoring of leaf expansion

    Directory of Open Access Journals (Sweden)

    Cronk Quentin CB

    2011-01-01

    Full Text Available Abstract Background Inkjet micropatterning is a versatile deposition technique with broad applications in numerous fields. However, its application in plant science is largely unexplored. Leaf expansion is one of the most important parameters in the field of plant science and many methods have been developed to examine differential expansion rates of different parts of the leaf lamina. Among them, methods based on the tracking of natural landmarks through digital imaging require a complicated setup in which the leaf must remain fixed and under tension. Furthermore, the resolution is limited to that of the natural landmarks, which are often difficult to find, particularly in young leaves. To study the fine scale expansion dynamics of the leaf lamina using artificial landmarks it is necessary to place small, noninvasive marks on a leaf surface and then recover the location of those marks after a period of time. Results To monitor leaf expansion in two dimensions, at very fine scales, we used a custom designed inkjet micropatterning system to print a grid composed of c. 0.19 mm2 cells on small developing leaves of ivy (Hedera helix using 40 μm dots at a spacing of c. 91 μm. The leaves in different growing stages were imaged under magnification to extract the coordinates of the marks which were then used in subsequent computer-assisted leaf expansion analyses. As an example we obtained quantified global and local expansion information and created expansion maps over the entire leaf surface. The results reveal a striking pattern of fine-scale expansion differences over short periods of time. In these experiments, the base of the leaf is a "cold spot" for expansion, while the leaf sinuses are "hot spots" for expansion. We have also measured a strong shading effect on leaf expansion. We discuss the features required to build an inkjet printing apparatus optimized for use in plant science, which will further maximize the range of tissues that can be

  4. [Bacterial vaginosis].

    Science.gov (United States)

    Romero Herrero, Daniel; Andreu Domingo, Antonia

    2016-07-01

    Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists.

  5. Comparing Leaf and Root Insertion

    Directory of Open Access Journals (Sweden)

    Jaco Geldenhuys

    2010-07-01

    Full Text Available We consider two ways of inserting a key into a binary search tree: leaf insertion which is the standard method, and root insertion which involves additional rotations. Although the respective cost of constructing leaf and root insertion binary search trees trees, in terms of comparisons, are the same in the average case, we show that in the worst case the construction of a root insertion binary search tree needs approximately 50% of the number of comparisons required by leaf insertion.

  6. Comparative leaf development in angiosperms.

    Science.gov (United States)

    Tsukaya, Hirokazu

    2014-02-01

    Recent accumulation of our knowledge on basic leaf development mechanisms in model angiosperm species has allowed us to pursue evolutionary development (evo/devo) studies of various kinds of leaf development. As a result, unexpected findings and clues have been unearthed aiding our understanding of the mechanisms involved in the diversity of leaf morphology, although the covered remain limited. In this review, we highlight recent findings of diversified leaf development in angiosperms. Copyright © 2013 The Author. Published by Elsevier Ltd.. All rights reserved.

  7. A hydroponic rice seedling culture model system for investigating proteome of salt stress in rice leaf.

    Science.gov (United States)

    Kim, Dea-Wook; Rakwal, Randeep; Agrawal, Ganesh Kumar; Jung, Young-Ho; Shibato, Junko; Jwa, Nam-Soo; Iwahashi, Yumiko; Iwahashi, Hitoshi; Kim, Du Hyun; Shim, Ie-Sung; Usui, Kenji

    2005-12-01

    By using an in vivo hydroponic rice seedling culture system, we investigated the physiological and biochemical responses of a model rice japonica cultivar Nipponbare to salt stress using proteomics and classical biochemical methods. Yoshida's nutrient solution (YS) was used to grow rice seedlings. YS-grown 18-day-old seedlings manifested highly stable and reproducible symptoms, prominently the wilting and browning of the 3rd leaf, reduced photosynthetic activity, inhibition in overall seedling growth, and failure to develop new (5th) leaf, when subjected to salt stress by transferring them to YS containing 130 mM NaCl for 4 days. As leaf response to salt stress is least investigated in rice by proteomics, we used the 3rd leaf as source material. A comparison of 2-DE protein profiles between the untreated control and salt-stressed 3rd leaves revealed 55 differentially expressed CBB-stained spots, where 47 spots were increased over the control. Of these changed spots, the identity of 33 protein spots (27 increased and 5 decreased) was determined by nESI-LC-MS/MS. Most of these identified proteins belonged to major metabolic processes like photosynthetic carbon dioxide assimilation and photorespiration, suggesting a good correlation between salt stress-responsive proteins and leaf morphology. Moreover, 2-DE immunoblot and enzymatic activity analyses of 3rd leaves revealed remarkable changes in the key marker enzymes associated with oxidative damage to salt stress: ascorbate peroxidase and lipid peroxidation were induced, and catalase was suppressed. These results demonstrate that hydroponic culture system is best suited for proteomics of salt stress in rice seedling.

  8. 7 CFR 29.2528 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture Regulations...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  9. 7 CFR 29.3033 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  10. 7 CFR 29.3525 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  11. Leaf growth of contrasting Poa species

    NARCIS (Netherlands)

    Fiorani, Fabio

    2002-01-01

    In the grass genus Poa a wide variation in final leaf size and leaf growth rate exists. In this thesis leaf growth was analyzed at different levels. At the cellular level, inherent variation in leaf elongation rate and final leaf size was correlated to the length of the elongation zone and to merist

  12. 7 CFR 29.1028 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  13. ESA uncovers Geminga's `hot spot'

    Science.gov (United States)

    2004-07-01

    16 July 2004 Astronomers using ESA’s X-ray observatory XMM-Newton have detected a small, bright ‘hot spot’ on the surface of the neutron star called Geminga, 500 light-years away. The hot spot is the size of a football field and is caused by the same mechanism producing Geminga’s X-ray tails. This discovery identifies the missing link between the X-ray and gamma-ray emission from Geminga. hi-res Size hi-res: 1284 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot This figure shows the effects of charged particles accelerated in the magnetosphere of Geminga. Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of particles kicked out by Geminga’s strong magnetic field, trail the neutron star as it moves about in space. Panel (b) shows how electrically charged particles interact with Geminga’s magnetic field. For example, if electrons (blue) are kicked out by the star, positrons (in red) hit the star’s magnetic poles like in an ‘own goal’. Panel (c) illustrates the size of Geminga’s magnetic field (blue) compared to that of the star itself at the centre (purple). The magnetic field is tilted with respect to Geminga’s rotation axis (red). Panel (d) shows the magnetic poles of Geminga, where charged particles hit the surface of the star, creating a two-million degrees hot spot, a region much hotter than the surroundings. As the star spins on its rotation axis, the hot spot comes into view and then disappears, causing the periodic colour change seen by XMM-Newton. An animated version of the entire sequence can be found at: Click here for animated GIF [low resolution, animated GIF, 5536 KB] Click here for AVI [high resolution, AVI with DIVX compression, 19128 KB] hi-res Size hi-res: 371 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (a) Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of

  14. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  15. The artificial leaf.

    Science.gov (United States)

    Nocera, Daniel G

    2012-05-15

    To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a

  16. Watermarking spot colors in packaging

    Science.gov (United States)

    Reed, Alastair; Filler, TomáÅ.¡; Falkenstern, Kristyn; Bai, Yang

    2015-03-01

    In January 2014, Digimarc announced Digimarc® Barcode for the packaging industry to improve the check-out efficiency and customer experience for retailers. Digimarc Barcode is a machine readable code that carries the same information as a traditional Universal Product Code (UPC) and is introduced by adding a robust digital watermark to the package design. It is imperceptible to the human eye but can be read by a modern barcode scanner at the Point of Sale (POS) station. Compared to a traditional linear barcode, Digimarc Barcode covers the whole package with minimal impact on the graphic design. This significantly improves the Items per Minute (IPM) metric, which retailers use to track the checkout efficiency since it closely relates to their profitability. Increasing IPM by a few percent could lead to potential savings of millions of dollars for retailers, giving them a strong incentive to add the Digimarc Barcode to their packages. Testing performed by Digimarc showed increases in IPM of at least 33% using the Digimarc Barcode, compared to using a traditional barcode. A method of watermarking print ready image data used in the commercial packaging industry is described. A significant proportion of packages are printed using spot colors, therefore spot colors needs to be supported by an embedder for Digimarc Barcode. Digimarc Barcode supports the PANTONE spot color system, which is commonly used in the packaging industry. The Digimarc Barcode embedder allows a user to insert the UPC code in an image while minimizing perceptibility to the Human Visual System (HVS). The Digimarc Barcode is inserted in the printing ink domain, using an Adobe Photoshop plug-in as the last step before printing. Since Photoshop is an industry standard widely used by pre-press shops in the packaging industry, a Digimarc Barcode can be easily inserted and proofed.

  17. Evaluation of SPOT imagery for the estimation of grassland biomass

    Science.gov (United States)

    Dusseux, P.; Hubert-Moy, L.; Corpetti, T.; Vertès, F.

    2015-06-01

    In many regions, a decrease in grasslands and change in their management, which are associated with agricultural intensification, have been observed in the last half-century. Such changes in agricultural practices have caused negative environmental effects that include water pollution, soil degradation and biodiversity loss. Moreover, climate-driven changes in grassland productivity could have serious consequences for the profitability of agriculture. The aim of this study was to assess the ability of remotely sensed data with high spatial resolution to estimate grassland biomass in agricultural areas. A vegetation index, namely the Normalized Difference Vegetation Index (NDVI), and two biophysical variables, the Leaf Area Index (LAI) and the fraction of Vegetation Cover (fCOVER) were computed using five SPOT images acquired during the growing season. In parallel, ground-based information on grassland growth was collected to calculate biomass values. The analysis of the relationship between the variables derived from the remotely sensed data and the biomass observed in the field shows that LAI outperforms NDVI and fCOVER to estimate biomass (R2 values of 0.68 against 0.30 and 0.50, respectively). The squared Pearson correlation coefficient between observed and estimated biomass using LAI derived from SPOT images reached 0.73. Biomass maps generated from remotely sensed data were then used to estimate grass reserves at the farm scale in the perspective of operational monitoring and forecasting.

  18. The worldwide leaf economics spectrum

    NARCIS (Netherlands)

    Wright, I.J.; Reich, P.B.; Westoby, M.; Ackerly, D.D.; Baruch, Z.; Bongers, F.J.J.M.; Cavender-Bares, J.; Chapin, T.; Cornelissen, J.H.C.; Diemer, M.; Flexas, J.; Garnier, E.; Groom, P.K.; Gulias, J.; Hikosaka, K.; Lamont, B.B.; Lee, T.; Lee, W.; Lusk, C.; Midgley, J.J.; Navas, M.L.; Niinements, Ü.; Oleksyn, J.; Osada, N.; Poorter, H.; Poot, P.; Prior, L.; Pyankov, V.I.; Roumet, C.; Thomas, S.C.; Tjoelker, M.G.; Veneklaas, E.J.; Villar, R.

    2004-01-01

    Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients

  19. A Hot Spot in Coma

    CERN Document Server

    Donnelly, R H; Forman, W R; Jones, C; Churazov, E; Gilfanov, M R

    1999-01-01

    We study the temperature structure of the central part (r<18' ~0.7 h50**-1 Mpc) of the Coma cluster of galaxies using ASCA data. Two different analysis methods produce results in good agreement with each other and reveal the presence of interesting structures in the gas temperature distribution. Globally, the average temperature in the center of the cluster is 9.0 +/- 0.6 keV in good agreement with previous results. Superimposed on this, we find a cool area with temperatures of 4-6 keV associated with a filament of X-ray emission extending southeast from the cluster center detected by Vikhlinin and coworkers. We also find a hot spot with a temperature of around 13 keV displaced north from the central peak of emission. The distribution of the gas temperatures and relative specific entropies suggests that the cool features are most likely gas stripped from a galaxy group centered on NGC 4874 falling toward the core from outside, while the hot spot located ``ahead'' of this in-falling gas is due to shock heat...

  20. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... in the formation of highly complex sessile communities, referred to as biofilms. Such microbial communities are often highly dynamic and heterogeneous in nature. Microbial biofilms are of great importance in a wide range of natural processes and industrial settings, from the commensal flora of the gastrointestinal...

  1. Integrating sustainable hunting in biodiversity protection in Central Africa: hot spots, weak spots, and strong spots.

    Directory of Open Access Journals (Sweden)

    John E Fa

    Full Text Available Wild animals are a primary source of protein (bushmeat for people living in or near tropical forests. Ideally, the effect of bushmeat harvests should be monitored closely by making regular estimates of offtake rate and size of stock available for exploitation. However, in practice, this is possible in very few situations because it requires both of these aspects to be readily measurable, and even in the best case, entails very considerable time and effort. As alternative, in this study, we use high-resolution, environmental favorability models for terrestrial mammals (N = 165 in Central Africa to map areas of high species richness (hot spots and hunting susceptibility. Favorability models distinguish localities with environmental conditions that favor the species' existence from those with detrimental characteristics for its presence. We develop an index for assessing Potential Hunting Sustainability (PHS of each species based on their ecological characteristics (population density, habitat breadth, rarity and vulnerability, weighted according to restrictive and permissive assumptions of how species' characteristics are combined. Species are classified into five main hunting sustainability classes using fuzzy logic. Using the accumulated favorability values of all species, and their PHS values, we finally identify weak spots, defined as high diversity regions of especial hunting vulnerability for wildlife, as well as strong spots, defined as high diversity areas of high hunting sustainability potential. Our study uses relatively simple models that employ easily obtainable data of a species' ecological characteristics to assess the impacts of hunting in tropical regions. It provides information for management by charting the geography of where species are more or less likely to be at risk of extinction from hunting.

  2. Integrating sustainable hunting in biodiversity protection in Central Africa: hot spots, weak spots, and strong spots.

    Science.gov (United States)

    Fa, John E; Olivero, Jesús; Farfán, Miguel Ángel; Márquez, Ana Luz; Vargas, Juan Mario; Real, Raimundo; Nasi, Robert

    2014-01-01

    Wild animals are a primary source of protein (bushmeat) for people living in or near tropical forests. Ideally, the effect of bushmeat harvests should be monitored closely by making regular estimates of offtake rate and size of stock available for exploitation. However, in practice, this is possible in very few situations because it requires both of these aspects to be readily measurable, and even in the best case, entails very considerable time and effort. As alternative, in this study, we use high-resolution, environmental favorability models for terrestrial mammals (N = 165) in Central Africa to map areas of high species richness (hot spots) and hunting susceptibility. Favorability models distinguish localities with environmental conditions that favor the species' existence from those with detrimental characteristics for its presence. We develop an index for assessing Potential Hunting Sustainability (PHS) of each species based on their ecological characteristics (population density, habitat breadth, rarity and vulnerability), weighted according to restrictive and permissive assumptions of how species' characteristics are combined. Species are classified into five main hunting sustainability classes using fuzzy logic. Using the accumulated favorability values of all species, and their PHS values, we finally identify weak spots, defined as high diversity regions of especial hunting vulnerability for wildlife, as well as strong spots, defined as high diversity areas of high hunting sustainability potential. Our study uses relatively simple models that employ easily obtainable data of a species' ecological characteristics to assess the impacts of hunting in tropical regions. It provides information for management by charting the geography of where species are more or less likely to be at risk of extinction from hunting.

  3. Integrating Sustainable Hunting in Biodiversity Protection in Central Africa: Hot Spots, Weak Spots, and Strong Spots

    Science.gov (United States)

    Fa, John E.; Olivero, Jesús; Farfán, Miguel Ángel; Márquez, Ana Luz; Vargas, Juan Mario; Real, Raimundo; Nasi, Robert

    2014-01-01

    Wild animals are a primary source of protein (bushmeat) for people living in or near tropical forests. Ideally, the effect of bushmeat harvests should be monitored closely by making regular estimates of offtake rate and size of stock available for exploitation. However, in practice, this is possible in very few situations because it requires both of these aspects to be readily measurable, and even in the best case, entails very considerable time and effort. As alternative, in this study, we use high-resolution, environmental favorability models for terrestrial mammals (N = 165) in Central Africa to map areas of high species richness (hot spots) and hunting susceptibility. Favorability models distinguish localities with environmental conditions that favor the species' existence from those with detrimental characteristics for its presence. We develop an index for assessing Potential Hunting Sustainability (PHS) of each species based on their ecological characteristics (population density, habitat breadth, rarity and vulnerability), weighted according to restrictive and permissive assumptions of how species' characteristics are combined. Species are classified into five main hunting sustainability classes using fuzzy logic. Using the accumulated favorability values of all species, and their PHS values, we finally identify weak spots, defined as high diversity regions of especial hunting vulnerability for wildlife, as well as strong spots, defined as high diversity areas of high hunting sustainability potential. Our study uses relatively simple models that employ easily obtainable data of a species' ecological characteristics to assess the impacts of hunting in tropical regions. It provides information for management by charting the geography of where species are more or less likely to be at risk of extinction from hunting. PMID:25372705

  4. Turning A New Leaf

    Institute of Scientific and Technical Information of China (English)

    CORRIE; DOSH

    2008-01-01

    Chinese-blend teas tap into American’s craving for caffeine Walking into the warm den of The Tea Spot,in the heart of New York’s Greenwich Village,entering students from nearby New York University are greeted with a blast of sweet,grassy scents that erases winter’s chill. A wall of canisters stretching from floor to ceiling sits behind the counter,with names such as"Madagascar Bourbon Vanilla"and"Gunpowder"emblazoned on them. Store manager Alice Seurattan offers up a sample of an Oolong blend,and says Chinese-blend teas comprise about 20 percent of the store’s available teas.

  5. Leaf chlorophyll content as a proxy for leaf photosynthetic capacity.

    Science.gov (United States)

    Croft, Holly; Chen, Jing M; Luo, Xiangzhong; Bartlett, Paul; Chen, Bin; Staebler, Ralf M

    2017-09-01

    Improving the accuracy of estimates of forest carbon exchange is a central priority for understanding ecosystem response to increased atmospheric CO2 levels and improving carbon cycle modelling. However, the spatially continuous parameterization of photosynthetic capacity (Vcmax) at global scales and appropriate temporal intervals within terrestrial biosphere models (TBMs) remains unresolved. This research investigates the use of biochemical parameters for modelling leaf photosynthetic capacity within a deciduous forest. Particular attention is given to the impacts of seasonality on both leaf biophysical variables and physiological processes, and their interdependent relationships. Four deciduous tree species were sampled across three growing seasons (2013-2015), approximately every 10 days for leaf chlorophyll content (ChlLeaf ) and canopy structure. Leaf nitrogen (NArea ) was also measured during 2014. Leaf photosynthesis was measured during 2014-2015 using a Li-6400 gas-exchange system, with A-Ci curves to model Vcmax. Results showed that seasonality and variations between species resulted in weak relationships between Vcmax normalized to 25°C (Vcmax25) and NArea (R(2)  = 0.62, P models to derive ChlLeaf . TBMs largely treat photosynthetic parameters as either fixed constants or varying according to leaf nitrogen content. This research challenges assumptions that simple NArea -Vcmax25 relationships can reliably be used to constrain photosynthetic capacity in TBMs, even within the same plant functional type. It is suggested that ChlLeaf provides a more accurate, direct proxy for Vcmax25 and is also more easily retrievable from satellite data. These results have important implications for carbon modelling within deciduous ecosystems. © 2017 Her Majesty the Queen in Right of Canada.

  6. On the relationship between leaf photosynthetic capacity and leaf chlorophyll and implications for simulating GPP in space and time

    Science.gov (United States)

    Houborg, R.; Cescatti, A.; Migliavacca, M.

    2012-12-01

    Advancing the use of remote sensing data for retrieving key vegetation physiological controls is of critical importance for modeling spatio-temporal variations in gross primary productivity (GPP) with high fidelity. Key land-surface model controls on GPP, such as the maximum rate of carboxylation (Vcmax) that governs leaf photosynthetic efficiency, are typically assigned fixed literature-based values for broad categories of vegetation types although in reality temporal and spatial variability can be significant in response to differences in plant phenology and physiological condition, nutrient availability and climate. Vcmax defines the biochemical capacity of leaves to assimilate CO2 and is related to the nitrogen content of leaves, which is indirectly related to leaf reflectance and transmittance spectra. However, the fact that Vcmax is a leaf level parameter complicates larger scale parameterizations based on remote sensing observations due to confounding influences from the canopy and soil. Thus a key challenge is to separate the leaf contribution associated with changes in Vcmax from the total remote sensing signal. Chlorophylls are vital pigments for photosynthesis and directly controls leaf absorption in the visible waveband region. Here we report on the utility of satellite-based leaf chlorophyll (Chl) retrievals for quantifying Vcmax variability in space and time, and look into a mechanistic methodology for exploiting Chl information within the Community Land Model (CLM4) for improved predictability of GPP. Chl is retrieved from Landsat imagery by inversion of leaf optics and canopy reflectance models within the framework of REGFLEC (REGularized canopy reFLECtance tool). The potential of Chl retrievals for constraining model simulations of GPP is evaluated at multiple flux tower sites.ig. 1 Benefit of using satellite-based leaf chlorophyll (Chl) for parameterizing Vcmax and constraining modeled carbon fluxes over the growing season at a corn site in

  7. Bacterial hydrodynamics

    CERN Document Server

    Lauga, Eric

    2015-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells yet they represent the bulk of the world's biomass, and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds-number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micron scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically-complex environments. Using hydrodynamics as an organizing framework, we review the biomechanics of bacterial motility and look ahead to future challenges.

  8. Antimicrobial compounds from leaf extracts of Jatropha curcas, Psidium guajava, and Andrographis paniculata.

    Science.gov (United States)

    Rahman, M M; Ahmad, S H; Mohamed, M T M; Ab Rahman, M Z

    2014-01-01

    The present research was conducted to discover antimicrobial compounds in methanolic leaf extracts of Jatropha curcas and Andrographis paniculata and ethanolic leaf extract of Psidium guajava and the effectiveness against microbes on flower preservative solution of cut Mokara Red orchid flowers was evaluated. The leaves were analyzed using gas chromatography-mass spectrometry. A total of nine, 66, and 29 compounds were identified in J. curcas, P. guajava, and A. paniculata leaf extracts, with five (88.18%), four (34.66%), and three (50.47%) having unique antimicrobial compounds, respectively. The experimental design on vase life was conducted using a completely randomized design with 10 replications. The flower vase life was about 6 days in the solution containing the P. guajava and A. paniculata leaf extracts at 15 mg/L. Moreover, solution with leaf extracts of A. paniculata had the lowest bacterial count compared to P. guajava and J. curcas. Thus, these leaf extracts revealed the presence of relevant antimicrobial compounds. The leaf extracts have the potential as a cut flower solution to minimize microbial populations and extend flower vase life. However, the activities of specific antimicrobial compounds and double or triple combination leaf extracts to enhance the effectiveness to extend the vase life need to be tested.

  9. Antimicrobial Compounds from Leaf Extracts of Jatropha curcas, Psidium guajava, and Andrographis paniculata

    Directory of Open Access Journals (Sweden)

    M. M. Rahman

    2014-01-01

    Full Text Available The present research was conducted to discover antimicrobial compounds in methanolic leaf extracts of Jatropha curcas and Andrographis paniculata and ethanolic leaf extract of Psidium guajava and the effectiveness against microbes on flower preservative solution of cut Mokara Red orchid flowers was evaluated. The leaves were analyzed using gas chromatography-mass spectrometry. A total of nine, 66, and 29 compounds were identified in J. curcas, P. guajava, and A. paniculata leaf extracts, with five (88.18%, four (34.66%, and three (50.47% having unique antimicrobial compounds, respectively. The experimental design on vase life was conducted using a completely randomized design with 10 replications. The flower vase life was about 6 days in the solution containing the P. guajava and A. paniculata leaf extracts at 15mg/L. Moreover, solution with leaf extracts of A. paniculata had the lowest bacterial count compared to P. guajava and J. curcas. Thus, these leaf extracts revealed the presence of relevant antimicrobial compounds. The leaf extracts have the potential as a cut flower solution to minimize microbial populations and extend flower vase life. However, the activities of specific antimicrobial compounds and double or triple combination leaf extracts to enhance the effectiveness to extend the vase life need to be tested.

  10. The effect of burdock leaf fraction on adhesion, biofilm formation, quorum sensing and virulence factors of Pseudomonas aeruginosa.

    Science.gov (United States)

    Lou, Z; Wang, H; Tang, Y; Chen, X

    2017-03-01

    This study aimed to evaluate the effect of a fraction of burdock (Arctium lappa L.) leaf on the initial adhesion, biofilm formation, quorum sensing and virulence factors of Pseudomonas aeruginosa. Antibiofilm activity of the burdock leaf fraction was studied by the method of crystal violet staining. When the concentration of the burdock leaf fraction was 2·0 mg ml(-1) , the inhibition rates on biofilm formation of P. aeruginosa were 100%. The burdock leaf fraction was found to inhibit the formation of biofilm by reducing bacterial surface hydrophobicity, decreasing bacterial aggregation ability and inhibiting swarming motility. Interestingly, the burdock leaf fraction inhibited the secretion of quorum-sensing (QS) signalling molecule 3-oxo-C12-HSL and interfered quorum sensing. Moreover, the QS-regulated pyocyanin and elastase were also inhibited. Chemical composition analysis by UPLC-MS showed 11 active compounds in the burdock leaf fraction. The burdock leaf fraction significantly inhibited the formation of biofilm and quorum sensing, as well as significantly decreased the content of virulence factors. This study introduces a natural and effective bacterial biofilm inhibitor, which could also significantly decrease the content of virulence factors and the drug resistance of P. aeruginosa. © 2016 The Society for Applied Microbiology.

  11. First Report of Leaf Rust Caused by Puccinia caricis in Farfugium japonicum in Korea.

    Science.gov (United States)

    Yun, Yeo Hong; Kwon, Hyuk Woo; Ahn, Hong Seok; Kim, Seong Hwan

    2015-09-01

    Farfugium japonicum is used in traditional medicine and as an edible herb in China and Korea. In July 2013, leaf spots were observed in F. japonicum seedlings at Ulleung Island, Gyeongsangbuk Province, Korea. Early symptoms on the leaf adaxial surface included roughly circular yellow spots that later developed brown, necrotic centers. The aecia were hypophyllous, cupulate, yellowish, 180~430 µm in diameter, clustered, and erumpent with a peridium with a recurved margin. The aeciospores were globoid, 14~17 × 13~16 µm, light yellow or colorless, and densely verrucose. The 28S rDNA sequence of the isolate was identical to each other and shared 99% identity with Puccinia caricis. This is the first report of rust caused by P. caricis in F. japonicum in Korea or elsewhere in the world.

  12. Identification of an emergent bacterial blight of garlic in Brazil

    Science.gov (United States)

    Outbreaks of a bacterial blight disease occurred on garlic (Allium sativum) cultivars Roxo Caxiense, Quiteria and Cacador in Southern Brazil, and threatened the main production regions of Rio Grande do Sul State. Symptoms were characterized by watersoaked reddish streaks along the leaf midrib, follo...

  13. Defective active silicon uptake affects some components of rice resistance to brown spot.

    Science.gov (United States)

    Dallagnol, Leandro J; Rodrigues, Fabrício A; Mielli, Mateus V B; Ma, Jian F; Datnoff, Lawrence E

    2009-01-01

    Rice is known to accumulate high amounts of silicon (Si) in plant tissue, which helps to decrease the intensity of many economically important rice diseases. Among these diseases, brown spot, caused by the fungus Bipolaris oryzae, is one of the most devastating because it negatively affects yield and grain quality. This study aimed to evaluate the importance of active root Si uptake in rice for controlling brown spot development. Some components of host resistance were evaluated in a rice mutant, low silicon 1 (lsi1), defective in active Si uptake, and its wild-type counterpart (cv. Oochikara). Plants were inoculated with B. oryzae after growing for 35 days in a hydroponic culture amended with 0 or 2 mMol Si. The components of host resistance evaluated were incubation period (IP), relative infection efficiency (RIE), area under brown spot progress curve (AUBSPC), final lesion size (FLS), rate of lesion expansion (r), and area under lesion expansion progress curve (AULEPC). Si content from both Oochikara and lsi1 in the +Si treatment increased in leaf tissue by 219 and 178%, respectively, over the nonamended controls. Plants from Oochikara had 112% more Si in leaf tissue than plants from lsi1. The IP of brown spot from Oochikara increased approximately 6 h in the presence of Si and the RIE, AUBSPC, FLS, r, and AULEPC were significantly reduced by 65, 75, 33, 36, and 35%, respectively. In the presence of Si, the IP increased 3 h for lsi1 but the RIE, AUBSPC, FLS, r, and AULEPC were reduced by only 40, 50, 12, 21, and 12%, respectively. The correlation between Si leaf content and IP was significantly positive but Si content was negatively correlated with RIE, AUBSPC, FLS, r, and AULEPC. Single degree-of-freedom contrasts showed that Oochikara and lsi1 supplied with Si were significantly different from those not supplied with Si for all components of resistance evaluated. This result showed that a reduced Si content in tissues of plants from lsi1 dramatically affected

  14. Relationships between phyllosphere bacterial communities and plant functional traits in a neotropical forest.

    Science.gov (United States)

    Kembel, Steven W; O'Connor, Timothy K; Arnold, Holly K; Hubbell, Stephen P; Wright, S Joseph; Green, Jessica L

    2014-09-23

    The phyllosphere--the aerial surfaces of plants, including leaves--is a ubiquitous global habitat that harbors diverse bacterial communities. Phyllosphere bacterial communities have the potential to influence plant biogeography and ecosystem function through their influence on the fitness and function of their hosts, but the host attributes that drive community assembly in the phyllosphere are poorly understood. In this study we used high-throughput sequencing to quantify bacterial community structure on the leaves of 57 tree species in a neotropical forest in Panama. We tested for relationships between bacterial communities on tree leaves and the functional traits, taxonomy, and phylogeny of their plant hosts. Bacterial communities on tropical tree leaves were diverse; leaves from individual trees were host to more than 400 bacterial taxa. Bacterial communities in the phyllosphere were dominated by a core microbiome of taxa including Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria, and Sphingobacteria. Host attributes including plant taxonomic identity, phylogeny, growth and mortality rates, wood density, leaf mass per area, and leaf nitrogen and phosphorous concentrations were correlated with bacterial community structure on leaves. The relative abundances of several bacterial taxa were correlated with suites of host plant traits related to major axes of plant trait variation, including the leaf economics spectrum and the wood density-growth/mortality tradeoff. These correlations between phyllosphere bacterial diversity and host growth, mortality, and function suggest that incorporating information on plant-microbe associations will improve our ability to understand plant functional biogeography and the drivers of variation in plant and ecosystem function.

  15. Voyager 1 Red Spot Movie

    Science.gov (United States)

    2000-01-01

    This movie shows the portion of Jupiter around the Great Red Spot as it swirls through more than 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storm shows how dynamic the Jovian atmosphere is.As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  16. Maize YABBY genes drooping leaf1 and drooping leaf2 affect agronomic traits by regulating leaf architecture

    Science.gov (United States)

    Leaf architectural traits, such as length, width and angle, directly influence canopy structure and light penetration, photosynthate production and overall yield. We discovered and characterized a maize (Zea mays) mutant with aberrant leaf architecture we named drooping leaf1 (drl1), as leaf blades ...

  17. Active suppression of a leaf meristem orchestrates determinate leaf growth.

    Science.gov (United States)

    Alvarez, John Paul; Furumizu, Chihiro; Efroni, Idan; Eshed, Yuval; Bowman, John L

    2016-10-06

    Leaves are flat determinate organs derived from indeterminate shoot apical meristems. The presence of a specific leaf meristem is debated, as anatomical features typical of meristems are not present in leaves. Here we demonstrate that multiple NGATHA (NGA) and CINCINNATA-class-TCP (CIN-TCP) transcription factors act redundantly, shortly after leaf initiation, to gradually restrict the activity of a leaf meristem in Arabidopsis thaliana to marginal and basal domains, and that their absence confers persistent marginal growth to leaves, cotyledons and floral organs. Following primordia initiation, the restriction of the broadly acting leaf meristem to the margins is mediated by the juxtaposition of adaxial and abaxial domains and maintained by WOX homeobox transcription factors, whereas other marginal elaboration genes are dispensable for its maintenance. This genetic framework parallels the morphogenetic program of shoot apical meristems and may represent a relic of an ancestral shoot system from which seed plant leaves evolved.

  18. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    Science.gov (United States)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  19. Ambystoma maculatum (spotted salamander). Reproduction

    Science.gov (United States)

    Glorioso, Brad M.; Waddle, Hardin; Hefner, Jeromi

    2012-01-01

    The Spotted Salamander is a wide-ranging salamander of the eastern United States that typically breeds in winter or early spring in ephemeral pools in lowland forests. Ambystoma maculatum is known to deposit 2-4 egg masses per year, each containing 1-250 eggs. As part of ongoing research into the ecology and reproductive biology of Spotted Salamanders in the Kisatchie District of Kisatchie National Forest in Natchitoches Parish, Louisiana, USA, we have been counting the number of embryos per egg mass. We captured seven female A. maculatum in a small pool, six of which were still gravid. We took standard measurements, including SVL, and then implanted a Passive Integrated Transponder (PIT tag) into each adult female as was the protocol. About an hour after processing these animals we marked new A. maculatum egg masses found in the same small pool using PVC pin flags pushed carefully through the outer jelly. We did not have enough time to process them that evening, and it was not until a few days later that we photographed those masses. We discovered that one of the masses contained a PIT tag in the outer jelly that corresponded to one of the six gravid females that were marked that same evening. To our knowledge, this is the first report of PIT tags being the means, albeit coincidentally, by which a particular egg mass of Ambystoma maculatum has been assigned to a particular female. For our purposes, losing the PIT tag from the adult female is counter to the goals of our study of this population, and we will no longer be implanting PIT tags into gravid females.

  20. Investigations on the necrotic injury to Taro Leaf by photochemical oxidants

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Y.; Takasaki, T.; Morikawa, M.; Matsumaru, T.; Shiratori, K.; Omichi, S.; Yoda, H.

    1975-03-01

    In August of 1969, taro, Colocasia antiquorum SCHOTT., planted in Ichihara city and neighboring towns in chiba prefecture, was observed to be suddenly damaged. The injury appeared as reddish-brown necrotic spots on interveinal mesophyll along the veins. Some injured leaves died back within few days. In order to resolve the reason for singular leaf injury, field surveys were made everywhere leaf injury occurred. The cause of taro leaf injury was determined to be as follows and attributed to air pollution. 1) Two plant growth chambers were prepared for this examinations. One was equipped with activated carbon and manganese dioxide filters for the purpose of removing air pollutants such as photochemical oxidants and sulfur dioxide. The other was without any filter. 2) When was planted taro in the filtered chamber, the injury was completely suppressed. In the filterless chamber the injury occurred many times throughout summer. 3) It was found that the air was sometimes polluted by photochemical oxidants and pollutants achieved more than 10 or 20 pphm in maximum concentration in the filterless chamber. Taro leaf injury developed immediately after occurrance of photochemical air pollutants. 4) At that time tobacco, Bel W3 which had been planted together with taro in filterless chamber, was severly injured. 5) Histological observation was carried out on cross sections of injured leaves. Their palisade cells and tissues were damaged and brown pigment sometimes accumulated in affected tissue, but epidermis and spongy tissues remained normal. 6) Ozone fumigation was examined on taro leaves with 30 pphm in concentration for 3 hours. Immediately after the fumigation water soaked spots developed on their leaves and turned to the chlorotic spots after 1 or 2 days. Most of chlorotic spots developed on interveinal mesophyll along the vein.

  1. Pregnancy Complications: Bacterial Vaginosis

    Science.gov (United States)

    ... Complications & Loss > Pregnancy complications > Bacterial vaginosis and pregnancy Bacterial vaginosis and pregnancy E-mail to a friend Please ... this page It's been added to your dashboard . Bacterial vaginosis (also called BV or vaginitis) is an infection ...

  2. Pregnancy Complications: Bacterial Vaginosis

    Science.gov (United States)

    ... Loss > Pregnancy complications > Bacterial vaginosis and pregnancy Bacterial vaginosis and pregnancy E-mail to a friend Please ... page It's been added to your dashboard . Bacterial vaginosis (also called BV or vaginitis) is an infection ...

  3. Bacterial vaginosis -- aftercare

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000687.htm Bacterial vaginosis - aftercare To use the sharing features on this ... back after you use the bathroom. Preventing Bacterial Vaginosis You can help prevent bacterial vaginosis by: Not ...

  4. Bacterial pericarditis (image)

    Science.gov (United States)

    Bacterial pericarditis is an inflammation of the pericardium, the sac-like covering of the heart, caused by a bacterial infection. The bacterial infection causes inflammation and swelling of the pericardium. Pain ...

  5. Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

    Directory of Open Access Journals (Sweden)

    Zahoor Ahmad BHAT

    2011-03-01

    Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

  6. Hot Spot Removal System: System description

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

  7. Rocky Mountain spotted fever in children.

    Science.gov (United States)

    Woods, Charles R

    2013-04-01

    Rocky Mountain spotted fever is typically undifferentiated from many other infections in the first few days of illness. Treatment should not be delayed pending confirmation of infection when Rocky Mountain spotted fever is suspected. Doxycycline is the drug of choice even for infants and children less than 8 years old.

  8. The biology of the California spotted owl

    Science.gov (United States)

    R.J. Gutiérrez; Douglas J. Tempel; M. Zachariah Peery

    2017-01-01

    The spotted owl (Strix occidentalis) is one of the most studied raptors in the world (Lõmus 2004) because forest management throughout its range has the potential to negatively affect owl populations. Information on the California spotted owl (S. o. occidentalis) has been summarized in several literature reviews (e.g.,...

  9. Front blind spot crashes in Hong Kong.

    Science.gov (United States)

    Cheng, Yuk Ki; Wong, Koon Hung; Tao, Chi Hang; Tam, Cheok Ning; Tam, Yiu Yan; Tsang, Cheuk Nam

    2016-09-01

    In 2012-2014, our laboratory had investigated a total of 9 suspected front blind spot crashes, in which the medium and heavy goods vehicles pulled away from rest and rolled over the pedestrians, who were crossing immediately in front of the vehicles. The drivers alleged that they did not see any pedestrians through the windscreens or the front blind spot mirrors. Forensic assessment of the goods vehicles revealed the existence of front blind spot zones in 3 out of these 9 accident vehicles, which were attributed to the poor mirror adjustments or even the absence of a front blind spot mirror altogether. In view of this, a small survey was devised involving 20 randomly selected volunteers and their goods vehicles and 5 out of these vehicles had blind spots at the front. Additionally, a short questionnaire was conducted on these 20 professional lorry drivers and it was shown that most of them were not aware of the hazards of blind spots immediately in front of their vehicles, and many did not use the front blind spot mirrors properly. A simple procedure for quick measurements of the coverage of front blind spot mirrors using a coloured plastic mat with dimensional grids was also introduced and described in this paper.

  10. [Clitoris and G spot: an intimate affair].

    Science.gov (United States)

    Foldes, P; Buisson, O

    2007-01-01

    Ultrasonography is a good means for studying the clitoris and its relationship with the G spot. We used it to demonstrate that clitoral bodies have a descending movement and come close to the distal anterior vaginal wall during a voluntary or reflex contraction of levator ani muscles. This fact could explain the particular sensitivity of the G spot and its role in the orgasm.

  11. HotSpot Software Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Walker, H; Homann, S G

    2009-03-12

    This Software Test Plan (STP) describes the procedures used to verify and validate that the HotSpot Health Physics Codes meet the requirements of its user base, which includes: (1) Users of the PC version of HotSpot conducting consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling. This plan is intended to meet Critical Recommendation 2 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  12. HotSpot Software Configuration Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Walker, H; Homann, S G

    2009-03-12

    This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  13. 7 CFR 29.3528 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3528 Section 29.3528 Agriculture... Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some extent by the size and shrinkage of the veins or fibers (See...

  14. 7 CFR 29.3036 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface...

  15. 7 CFR 28.415 - Low Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Low Middling Light Spotted Color. 28.415 Section 28... Spotted Color. Low Middling Light Spotted Color is color which in spot or color, or both, is between Low Middling Color and Low Middling Spotted Color....

  16. 7 CFR 28.412 - Strict Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Light Spotted Color. 28.412 Section 28... Light Spotted Color. Strict Middling Light Spotted Color is color which in spot or color, or both, is between Strict Middling Color and Strict Middling Spotted Color....

  17. 7 CFR 28.413 - Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Light Spotted Color. 28.413 Section 28.413... Spotted Color. Middling Light Spotted Color is color which in spot or color, or both, is between Middling Color and Middling Spotted Color....

  18. 7 CFR 28.411 - Good Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Good Middling Light Spotted Color. 28.411 Section 28... Light Spotted Color. Good Middling Light Spotted Color is color which in spot or color, or both, is between Good Middling Color and Good Middling Spotted Color....

  19. Physico-chemical characterization of banana varieties resistant to black leaf streak disease for industrial purposes

    Directory of Open Access Journals (Sweden)

    Rossana Catie Bueno de Godoy

    2016-01-01

    Full Text Available ABSTRACT: Cultivated bananas have very low genetic diversity making them vulnerable to diseases such as black-Sigatoka leaf spot. However, the decision to adopt a new banana variety needs to be based on a robust evaluation of agronomical and physical-chemical characteristics. Here, we characterize new banana varieties resistant to black-Sigatoka leaf spot and compare them to the most widely used traditional variety (Grand Naine. Each variety was evaluated for a range of physic-chemical attributes associated with industrial processing and flavor: pH, TTA, TSS/TTA, total sugars, reducing sugars and non-reducing sugars, humidity, total solids and yield. The Thap Maeo variety had the highest potential as a substitute for the Grand Naine variety, having higher levels of total soluble solids, reducing sugars, total sugars and humidity. The Caipira and FHIA 2 varieties also performed well in comparison with the Grand Naine variety. Cluster analysis indicated that the Grand Naine variety was closely associated with varieties from the Gross Michel subgroup (Bucaneiro, Ambrosia and Calipso and the Caipira variety, all of which come from the same AAA genomic group. It was concluded that several of the new resistant varieties could potentially substitute the traditional variety in areas affected by black-Sigatoka leaf spot disease.

  20. Metabolic adaptation, a specialized leaf organ structure and vascular responses to diurnal N

    NARCIS (Netherlands)

    Brouwer, Paul; Bräutigam, Andrea; Buijs, Valerie A.; Tazelaar, Anne O.E.; Werf, van der Adrie; Schlüter, Urte; Reichart, Gert Jan; Bolger, Anthony; Usadel, Björn; Weber, Andreas P.M.; Schluepmann, Henriette

    2017-01-01

    Sustainable agriculture demands reduced input of man-made nitrogen (N) fertilizer, yet N2 fixation limits the productivity of crops with heterotrophic diazotrophic bacterial symbionts. We investigated floating ferns from the genus Azolla that host phototrophic diazotrophic Nostoc azollae in leaf

  1. Green synthesis, antimicrobial and cytotoxic effects of silver nanoparticles mediated by Eucalyptus camaldulensis leaf extract

    Directory of Open Access Journals (Sweden)

    Afrah Eltayeb Mohammed

    2015-05-01

    Conclusions: Our findings indicated that extracellular synthesis of AgNPs mediated by E. camaldulensis leaf extract had an efficient bactericidal activity against the bacterial species tested. The exact mechanism of the extracellular biosynthesis of metal NP was not well understood. Further studies are needed to highlight the biosynthesis process of AgNPs and also to characterize the toxicity effect of these particles.

  2. Management of almond leaf scorch disease: long term data on yield, tree vitality, and disease progress

    Science.gov (United States)

    Almond leaf scorch (ALS) disease has been a chronic problem for California almond growers. This disease is caused by the bacterial pathogen Xylella fastidiosa and is transmitted by xylem-feeding insects. Previous research suggested that retaining, rather than roguing, ALS-affected trees may be more ...

  3. Genetics of Ophraella leaf beetles

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposal is to collect samples of each species of Ophraella leaf beetle encountered, not to exceed 50 specimens per species, for genetic analysis using DNA...

  4. Dermoscopy of black-spot poison ivy.

    Science.gov (United States)

    Rader, Ryan K; Mu, Ruipu; Shi, Honglan; Stoecker, William V; Hinton, Kristen A

    2012-10-15

    Black-spot poison ivy is an uncommon presentation of poison ivy (Toxicodendron) allergic contact dermatitis. A 78-year-old sought evaluation of a black spot present on her right hand amid pruritic vesicles. The presentation of a black spot on the skin in a clinical context suggesting poison ivy is indicative of black-spot poison ivy. Dermoscopy revealed a jagged, centrally homogeneous, dark brown lesion with a red rim. A skin sample was obtained and compared against a poison ivy standard using ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). This finding confirmed the presence of multiple urushiol congeners in the skin sample. Black-spot poison ivy may be added to the list of diagnoses that show a specific dermoscopic pattern.

  5. Laser Spot Detection Based on Reaction Diffusion

    Science.gov (United States)

    Vázquez-Otero, Alejandro; Khikhlukha, Danila; Solano-Altamirano, J. M.; Dormido, Raquel; Duro, Natividad

    2016-01-01

    Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations. PMID:26938537

  6. Laser Spot Detection Based on Reaction Diffusion

    Directory of Open Access Journals (Sweden)

    Alejandro Vázquez-Otero

    2016-03-01

    Full Text Available Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

  7. Agave Americana Leaf Fibers

    Directory of Open Access Journals (Sweden)

    Ashish Hulle

    2015-02-01

    Full Text Available The growing environmental problems, the problem of waste disposal and the depletion of non-renewable resources have stimulated the use of green materials compatible with the environment to reduce environmental impacts. Therefore, there is a need to design products by using natural resources. Natural fibers seem to be a good alternative since they are abundantly available and there are a number of possibilities to use all the components of a fiber-yielding crop; one such fiber-yielding plant is Agave Americana. The leaves of this plant yield fibers and all the parts of this plant can be utilized in many applications. The “zero-waste” utilization of the plant would enable its production and processing to be translated into a viable and sustainable industry. Agave Americana fibers are characterized by low density, high tenacity and high moisture absorbency in comparison with other leaf fibers. These fibers are long and biodegradable. Therefore, we can look this fiber as a sustainable resource for manufacturing and technical applications. Detailed discussion is carried out on extraction, characterization and applications of Agave Americana fiber in this paper.

  8. Why do leaf-tying caterpillars abandon their leaf ties?

    Directory of Open Access Journals (Sweden)

    Michelle Sliwinski

    2013-09-01

    Full Text Available Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats, but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently

  9. Karhunen-Loeve Transform and Sparse Representation Based Plant Leaf Disease Recognition

    Directory of Open Access Journals (Sweden)

    Tian Jie

    2013-09-01

    Full Text Available To improve the classification accuracy rate of apple leaf disease images and solve the problem of dimension redundancy in feature extraction, Karhunen-Loeve (K-L transform and sparse representation are applied to apple leaf disease recognition. Firstly 9 color features and 8 texture features of disease leaf images are extracted and taken as feature vectors after dimensionality reduction by the K-L transform. Then, for each of apple mosaic virus, apple rust and apple alternaria leaf spot, 40 apple leaf images are selected as the training samples, whose feature vectors are made up of the dictionary of the sparse representation, respectively. Each testing sample is classified into the class with the minimal residual. The identifying results using the proposed method are analyzed and compared with those of the Support Vector Machine (SVM and original sparse representation method. The average classification accuracy rate of the proposed method is 94.18 %, which confirms its good robustness. In addition, the proposed method not only improves the plant leaf disease classification accuracy but also solves the redundancy problem of the extracted features.

  10. Root bacterial endophytes alter plant phenotype, but not physiology

    Directory of Open Access Journals (Sweden)

    Jeremiah A. Henning

    2016-11-01

    Full Text Available Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant phenotype. We chose three bacterial strains that differed in predicted metabolic capabilities, plant hormone production and metabolism, and secondary metabolite synthesis. We inoculated each bacterial strain on a single genotype of Populus trichocarpa and measured the response of plant growth related traits (root:shoot, biomass production, root and leaf growth rates and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light–Asat, and saturating CO2–Amax. Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf growth rate up to 137% relative to non-inoculated control plants, evidence that plants respond to bacteria by modifying morphology. However, endophyte inoculation had no influence on total plant biomass and photosynthetic traits (net photosynthesis, chlorophyll content. In sum, bacterial inoculation did not significantly increase plant carbon fixation and biomass, but their presence altered where and how carbon was being allocated in the plant host.

  11. Immunoglobulin genes and antibody responses in the spotted wolffish (Anarhichas minor Olafsen).

    Science.gov (United States)

    Espelid, S; Halse, M; Solem, S T; Jørgensen, T O

    2001-07-01

    The spotted wolffish Anarhichas minor Olafsen is a promising new species in aquaculture in the cold waters of northern Norway. In this paper, some basic immunological studies of this marine species are reported. Of comparative interest are the cDNA sequences of the immunoglobulin transcript and the antibody responses to model antigens. Of more practical importance are the humoral immune responses and antibody specificities to potentially pathogenic bacteria. Full length cDNA clones encoding the immunoglobulin heavy and light chains in the spotted wolffish were sequenced demonstrating variable degrees of similarity to other teleost fish species. Also in the spotted wolffish the CH4 domain was deleted in the transmembrane form of the immunoglobulin heavy chain (IgH) as a receptor on B cells, with the transmembrane exon spliced directly to the CH3 domain. The antibody responses to various antigens like hapten-carrier molecules, protein antigens and bacterial pathogens were relatively high, but with some interesting exceptions. Anti-hapten responses to NIP and FITC were high while anti-DNS responses were low, but more surprisingly, there was hardly any B-cell response to the carrier molecule LPH. On the other hand, protein antigens like CGG and BSA were highly immunogenic in the spotted wolffish as were the bacterial antigens Vibrio anguillarum, V. salmonicida and Aeromonas salmonicida.

  12. Indirect selection for resistance to ear rot and leaf diseases in maize lines using biplots.

    Science.gov (United States)

    Pereira, G S; Camargos, R B; Balestre, M; Von Pinho, R G; C Melo, W M

    2015-09-21

    Leaf disease and ear rot have caused reductions in maize yield in Brazil and other producer countries. Therefore, the aims of this study were to analyze the association between husked ear yield and the severity of maize white spot, gray leaf spot, helminthosporium, and ear rot caused by Fusarium verticillioides and Diplodia maydis using biplots in a mixed-model approach. The responses of 238 lines introduced to Brazil and four controls were evaluated using an incomplete block design with three replicates in two locations: Lavras and Uberlândia, Minas Gerais, Brazil. Two experiments were conducted in each location, one with F. verticillioides and the other with D. maydis. The mixed models elucidated the relationship between yield, leaf disease, and ear disease. Significant genotype x environment and genotype x pathogen interactions were observed. In conclusion, husked ear yield is more associated with ear rot than with the leaf diseases evaluated, justifying the indirect selection for resistance to kernel rot in maize-F. verticillioides and maize-D. maydis pathosystems by yield evaluation.

  13. Cytopathological changes in Schefflera actinophylla Harms. naturally infected with impatiens necrotic spot virus (INSV

    Directory of Open Access Journals (Sweden)

    Anna Rudzińska-Langwald

    2014-01-01

    Full Text Available Plants of Schefflera actinophylla Harms. with stunted growth, chlorotic and necrotic spots and patterns, leaf epinasty and distortion are infected with impatiens necrotic spot virus classified as a member of genus Tospovirus. Studies with electron microscope revealed that in cells of S. actinophylla leaves there were no virus particle inclusions typical for tospovirus infection, but only single particles were present. The isolate of INSV was defective and the amount of INSV particles was strongly reduced in Schefflera plants. Some inclusions (I type were composed of short branched cisterns of endoplasmic reticulum and a dark substance forming characteristic bands. The II type represented inclusions that were usually ballshaped and composed of a dark substance resembling that of the I type, but not accompanied by endoplasmic reticulum cisterns. The III type of inclusions was composed of dark, osmophilic masses. The inclusions present in the cells differ from those typical for tospovirus infection.

  14. Superluminal Spot Pair Events in Astronomical Settings: Sweeping Beams

    CERN Document Server

    Nemiroff, Robert J

    2014-01-01

    Sweeping beams of light can cast spots moving with superluminal speeds across scattering surfaces. Such faster-than-light speeds are well-known phenomena that do not violate special relativity. It is shown here that under certain circumstances, superluminal spot pair creation and annihilation events can occur that provide unique information to observers. These spot pair events are {\\it not} particle pair events -- they are the sudden creation or annihilation of a pair of relatively illuminated spots on a scattering surface. Real spot pair illumination events occur unambiguously on the scattering surface when spot speeds diverge, while virtual spot pair events are observer dependent and perceived only when real spot radial speeds cross the speed of light. Specifically, a virtual spot pair creation event will be observed when a real spot's speed toward the observer drops below $c$, while a virtual spot pair annihilation event will be observed when a real spot's radial speed away from the observer rises above $c...

  15. Mutualistic ants as an indirect defence against leaf pathogens.

    Science.gov (United States)

    González-Teuber, Marcia; Kaltenpoth, Martin; Boland, Wilhelm

    2014-04-01

    Mutualistic ants are commonly considered as an efficient indirect defence against herbivores. Nevertheless, their indirect protective role against plant pathogens has been scarcely investigated. We compared the protective role against pathogens of two different ant partners, a mutualistic and a parasitic ant, on the host plant Acacia hindsii (Fabaceae). The epiphytic bacterial community on leaves was evaluated in the presence and absence of both ant partners by cultivation and by 454 pyrosequencing of the 16S rRNA gene. Pathogen-inflicted leaf damage, epiphytic bacterial abundance (colony-forming units) and number of operational taxonomic units (OTUs) were significantly higher in plants inhabited by parasitic ants than in plants inhabited by mutualistic ants. Unifrac unweighted and weighted principal component analyses showed that the bacterial community composition on leaves changed significantly when mutualistic ants were removed from plants or when plants were inhabited by parasitic ants. Direct mechanisms provided by ant-associated bacteria would contribute to the protective role against pathogens. The results suggest that the indirect defence of mutualistic ants also covers the protection from bacterial plant pathogens. Our findings highlight the importance of considering bacterial partners in ant-plant defensive mutualisms, which can contribute significantly to ant-mediated protection from plant pathogens. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  16. Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

    DEFF Research Database (Denmark)

    Bøgh, Eva; Houborg, R; Bienkowski, J

    2013-01-01

    sensing images acquired from the HRG and HRVIR sensors aboard the SPOT satellites were used to assess the predictability of LAI, CHLl and Nl. Five spectral vegetation indices (SVIs) were used (the Normalized Difference Vegetation index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green......Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and they play a significant role in the global cycles of carbon, nitrogen and water. Remote sensing data from satellites can be used to estimate leaf area index (LAI), leaf...... area, species variations, and spatial variations in nutrient availability. Information on Nl and total Nc pools within the landscapes is important for the spatial evaluation of nitrogen and carbon cycling processes. The upcoming Sentinel-2 satellite mission will provide new multiple narrow-band data...

  17. CMB Cold Spot from Inflationary Feature Scattering

    CERN Document Server

    Wang, Yi

    2015-01-01

    We propose a "feature-scattering" mechanism to explain the cosmic microwave background cold spot seen from {\\it WMAP} and {\\it Planck} maps. If there are hidden features in the potential of multi-field inflation, the inflationary trajectory can be scattered by such features. The scattering is controlled by the amount of isocurvature fluctuations, and thus can be considered as a mechanism to convert isocurvature fluctuations into curvature fluctuations. This mechanism predicts localized cold spots (instead of hot ones) on the CMB. In addition, it may also bridge a connection between the cold spot and a dip on the CMB power spectrum at $\\ell \\sim 20$.

  18. Calonectria spp. causing leaf spot, crown and root rot of ornamental plants in Tunisia

    NARCIS (Netherlands)

    Lombard, L.; Polizzi, G.; Guarnaccia, V.; Vitale, A.; Crous, P.W.

    2012-01-01

    Calonectria spp. are important pathogens of ornamental plants in nurseries, especially in the Northern Hemisphere. They are commonly associated with a wide range of disease symptoms of roots, leaves and shoots. During a recent survey in Tunisia, a number of Calonectria spp. were isolated from tissue

  19. Calonectria spp. causing leaf spot, crown and root rot of ornamental plants in Tunisia

    NARCIS (Netherlands)

    Lombard, L.; Polizzi, G.; Guarnaccia, V.; Vitale, A.; Crous, P.W.

    2011-01-01

    Calonectria spp. are important pathogens of ornamental plants in nurseries, especially in the Northern Hemisphere. They are commonly associated with a wide range of disease symptoms of roots, leaves and shoots. During a recent survey in Tunisia, a number of Calonectria spp. were isolated from tissue

  20. Genomics of peanut leaf-spot pathogens; and RNA-interference-mediated control of aflatoxins

    Science.gov (United States)

    An overview update of the research done at USDA-ARS National Peanut Research Laboratory will be presented: including: the release of the Cercospora arachidicola genome, sequencing of Cercosporidium personatum, a workflow to study genetic diversity of aflatoxigenic Aspergillus, and progress on the us...

  1. Quantitative trait loci (QTLs) for resistance to gray leaf spot and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... Kenya Agricultural Research Institute, Biotechnology Centre, P.O. Box 14733, Nairobi 00800. Accepted 2 .... two types of resistance against P. sorghi: partial and race-specific. .... complete block design with three replicates.

  2. First report of Alternaria alternata causing leaf spot on Ruth's golden aster (Pityopsis ruthii) in Tennessee

    Science.gov (United States)

    Ruth’s golden aster, Pityopsis ruthii (Small), is an endangered, herbaceous perennial plant that is only endemic to small sections of the Hiwassee and Ocoee Rivers, in Polk County, Tennessee. In July 2015, a greenhouse grown plant exhibited symptoms of disease that included elongated brown lesions o...

  3. prevalence of angular leaf spot disease and sources of resistance in ...

    African Journals Online (AJOL)

    USER

    1International Centre for Tropical Agriculture (CIAT), P. O. Box 6247, Kampala, Uganda ... (Received 1 July, 2016; accepted 17 February, 2017) ... practices and environmental factors on the disease prevalence in the country to facilitate ...

  4. Disease variation and chemical control of Ramularia leaf spot in sugar beet

    DEFF Research Database (Denmark)

    Thach, Tine; Munk, Lisa; Hansen, Anne Lisbet

    2013-01-01

    in field trials, a semi-field trial and an in vitro test using the compounds pyraclostrobin, epoxiconazole, difenoconazole and propiconazole. Dose response trials with epoxiconazole from two seasons showed both reduced efficacy and yield responses from low doses. They also proved that the optimal input...... of fungicides varies significantly between seasons depending on disease severity. A sensitivity test of R. beticola to different fungicides showed a normal distribution of sensitivity with no sign of resistance development to either strobilurins or triazoles. Results from a semi-field trial showed both good...... preventive and curative effects with 84–100% disease control from epoxiconazole, difenoconazole and pyraclostrobin. In order to optimize an IPM control strategy better forecasting systems are needed along with cultivars providing higher levels of resistance to the disease....

  5. aqueous plant extracts for control of groundnut leaf spot in burkina ...

    African Journals Online (AJOL)

    ACSS

    2017-08-08

    Aug 8, 2017 ... African Crop Science Journal by African Crop Science Society is licensed under a Creative .... fruits of the other plants species were dried in shade at ... disease, 2 = lesions present on lower leaves ..... Plant Pathology Journal.

  6. Severity of angular leaf spot and rust diseases on common beans in ...

    African Journals Online (AJOL)

    ACSS

    the incidence and severity of ALS in five bean agro-ecologies within Uganda was ... Key words: Common beans, disease management, Phaseolus vulgaris, ... plants has been shown to reduce pest and ... plant nutrition through organic soil.

  7. Pseudocercospora opuntiae sp. nov., the causal organism of cactus leaf spot in Mexico

    NARCIS (Netherlands)

    Ayala-Escobar, V.; Jesús Yáñez-Morales, de M.; Braun, U.; Groenewald, J.Z.; Crous, P.W.

    2006-01-01

    Pseudocercospora opuntiae is newly described from Opuntia spp. from Mexico, where it causes a serious disease of this host. Although P. opuntiae is morphologically similar to other members of the genus with pigmented conidia and conidiophores, and unthickened, not darkened conidiogenous scars, DNA s

  8. Experimental and simulated strength of spot welds

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Bennedbæk, Rune A.K.; Larsen, Morten B.

    2014-01-01

    Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load-elongation cu......Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load......-elongation curves revealing the maximum load and the elongation at break. Welding and strength testing is simulated by SORPAS® 3D, which allows the two processes to be prepared in a combined simulation, such that the simulated welding properties are naturally applied to the simulation of strength testing. Besides...

  9. How Many Spots Does a Cheetah Have?

    Science.gov (United States)

    Reed, Kristine M.

    2000-01-01

    Describes first grade students' mathematical investigation of the number of spots on a cheetah. The exploration of counting and estimation strategies that grew from the investigation gives evidence that mathematicians come in all ages. (ASK)

  10. Tissue Testing Can Spot Zika at Birth

    Science.gov (United States)

    ... 166828.html Tissue Testing Can Spot Zika at Birth: CDC Just 1 in 10 possible cases actually ... havoc on babies, but diagnosing the infection before birth remains a challenge. Now, there's some good news: ...

  11. Scientists Spot Genes Behind Crohn's, Ulcerative Colitis

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_166957.html Scientists Spot Genes Behind Crohn's, Ulcerative Colitis Large study finds key ... Researchers say they've come closer to pinpointing genes linked with inflammatory bowel diseases such as Crohn's ...

  12. SPOT Controlled Image Base 10 meter

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — SPOT Controlled Image Base 10 meter (CIB-10) is a collection of orthorectified panchromatic (grayscale) images. The data were acquired between 1986 and 1993 by the...

  13. A comprehensive overview of the Cold Spot

    CERN Document Server

    Vielva, P

    2010-01-01

    The report of a significant deviation of the CMB temperature anisotropies distribution from Gaussianity (soon after the public release of the WMAP data in 2003) has become one of the most solid WMAP anomalies. This detection grounds on an excess of the kurtosis of the Spherical Mexican Hat Wavelet coefficients at scales of around 10 degrees. At these scales, a prominent feature --located in the southern Galactic hemisphere-- was highlighted from the rest of the SMHW coefficients: the Cold Spot. This article presents a comprehensive overview related to the study of the Cold Spot, paying attention to the non-Gaussianity detection methods, the morphological characteristics of the Cold Spot, and the possible sources studied in the literature to explain its nature. Special emphasis is made on the Cold Spot compatibility with a cosmic texture, commenting on future tests that would help to give support or discard this hypothesis.

  14. SPOT Controlled Image Base 10 meter

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — SPOT Controlled Image Base 10 meter (CIB-10) is a collection of orthorectified panchromatic (grayscale) images. The data were acquired between 1986 and 1993 by the...

  15. How Many Spots Does a Cheetah Have?

    Science.gov (United States)

    Reed, Kristine M.

    2000-01-01

    Describes first grade students' mathematical investigation of the number of spots on a cheetah. The exploration of counting and estimation strategies that grew from the investigation gives evidence that mathematicians come in all ages. (ASK)

  16. Measuring microfocus focal spots using digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Fry, David A [Los Alamos National Laboratory

    2009-01-01

    Measurement of microfocus spot size can be important for several reasons: (1) Quality assurance during manufacture of microfocus tubes; (2) Tracking performance and stability of microfocus tubes; (3) Determining magnification (especially important for digital radiography where the native spatial resolution of the digital system is not adequate for the application); (4) Knowledge of unsharpness from the focal spot alone. The European Standard EN 12543-5 is based on a simple geometrical method of calculating focal spot size from unsharpness of high magnification film radiographs. When determining microfocus focal spot dimensions using unsharpness measurements both signal-to-noise (SNR) and magnification can be important. There is a maximum accuracy that is a function of SNR and therefore an optimal magnification. Greater than optimal magnification can be used but it will not increase accuracy.

  17. HST image of Saturn's 'white spot'

    Science.gov (United States)

    1990-01-01

    Saturn's 'white spot' or cloud believed to be ammonia ice crystals recorded by the Hubble Space Telescope (HST) planetary camera in blue and infrared light. HST data was computer-processed improving the image sharpness.

  18. White-spot disease of salmon fry

    Science.gov (United States)

    Mazuranich, J.J.; Nielson, W.E.

    1959-01-01

     White-spot disease, sometimes referred to as coagulated-yolk disease, has been associated with excessive mortalities occurring among the fry and early fingerling stages of the fall chinook salmon (Oncorhynchus tshawytacha) at the U.S. Fish-Cultural Stations at Carson, Cook, Underwood, and Willard, Washington. This disease of eggs and fry should not be confused with the "white-spot" infection that is caused in fingerlings by members of the protozoan genus Ichthyophthirius.

  19. Modeling deflagration waves out of hot spots

    Science.gov (United States)

    Partom, Yehuda

    2017-01-01

    It is widely accepted that shock initiation and detonation of heterogeneous explosives comes about by a two-step process known as ignition and growth. In the first step a shock sweeping through an explosive cell (control volume) creates hot spots that become ignition sites. In the second step, deflagration waves (or burn waves) propagate out of those hot spots and transform the reactant in the cell into reaction products. The macroscopic (or average) reaction rate of the reactant in the cell depends on the speed of those deflagration waves and on the average distance between neighboring hot spots. Here we simulate the propagation of deflagration waves out of hot spots on the mesoscale in axial symmetry using a 2D hydrocode, to which we add heat conduction and bulk reaction. The propagation speed of the deflagration waves may depend on both pressure and temperature. It depends on pressure for quasistatic loading near ambient temperature, and on temperature at high temperatures resulting from shock loading. From the simulation we obtain deflagration fronts emanating out of the hot spots. For 8 to 13 GPa shocks, the emanating fronts propagate as deflagration waves to consume the explosive between hot spots. For higher shock levels deflagration waves may interact with the sweeping shock to become detonation waves on the mesoscale. From the simulation results we extract average deflagration wave speeds.

  20. Unblinding the dark matter blind spots

    Science.gov (United States)

    Han, Tao; Kling, Felix; Su, Shufang; Wu, Yongcheng

    2017-02-01

    The dark matter (DM) blind spots in the Minimal Supersymmetric Standard Model (MSSM) refer to the parameter regions where the couplings of the DM particles to the Z-boson or the Higgs boson are almost zero, leading to vanishingly small signals for the DM direct detections. In this paper, we carry out comprehensive analyses for the DM searches under the blind-spot scenarios in MSSM. Guided by the requirement of acceptable DM relic abundance, we explore the complementary coverage for the theory parameters at the LHC, the projection for the future underground DM direct searches, and the indirect searches from the relic DM annihilation into photons and neutrinos. We find that (i) the spin-independent (SI) blind spots may be rescued by the spin-dependent (SD) direct detection in the future underground experiments, and possibly by the indirect DM detections from IceCube and SuperK neutrino experiments; (ii) the detection of gamma rays from Fermi-LAT may not reach the desirable sensitivity for searching for the DM blind-spot regions; (iii) the SUSY searches at the LHC will substantially extend the discovery region for the blind-spot parameters. The dark matter blind spots thus may be unblinded with the collective efforts in future DM searches.

  1. Spatial structuring of bacterial communities within individual Ginkgo biloba trees.

    Science.gov (United States)

    Leff, Jonathan W; Del Tredici, Peter; Friedman, William E; Fierer, Noah

    2015-07-01

    Plant-associated microorganisms affect the health of their hosts in diverse ways, yet the distribution of these organisms within individual plants remains poorly understood. To address this knowledge gap, we assessed the spatial variability in bacterial community diversity and composition found on and in aboveground tissues of individual Ginkgo biloba trees. We sampled bacterial communities from > 100 locations per tree, including leaf, branch and trunk samples and used high-throughput sequencing of the 16S rRNA gene to determine the diversity and composition of these communities. Bacterial community structure differed strongly between bark and leaf samples, with bark samples harbouring much greater bacterial diversity and a community composition distinct from leaves. Within sample types, we observed clear spatial patterns in bacterial diversity and community composition that corresponded to the samples' proximity to the exterior of the tree. The composition of the bacterial communities found on trees is highly variable, but this variability is predictable and dependent on sampling location. Moreover, this work highlights the importance of carefully considering plant spatial structure when characterizing the microbial communities associated with plants and their impacts on plant hosts.

  2. Biophysical control of leaf temperature

    Science.gov (United States)

    Dong, N.; Prentice, I. C.; Wright, I. J.

    2014-12-01

    In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (ΔT), the latter to the transpiration rate. We present field measurements of ΔT which confirm the existence of a 'crossover temperature' in the 25-30˚C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (ω) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ΔT) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf

  3. RELATIONSHIP BETWEEN MANGOSTEEN LEAF NITROGEN CONTENTS AND LEAF SPAD VALUES

    Directory of Open Access Journals (Sweden)

    Eko Setiawan

    2014-03-01

    Full Text Available We investigated nitrogen contents on mangosteen leaf and related on leaf SPAD value. The experiment was conducted using mangosteen trees grown in commercial orchard in Bogor, Indonesia during May to October 2010. Mangosteen trees of 3 different ages, young (20-year-old, middle-aged (35-year-old, and old (50-year-old trees, each of five trees, were selected for study, and the canopy of each tree was divided into 9 sectors based on height (bottom, middle, top and width (inner, center, outer. SPAD values had a negative correlation with leaf N content in all ages and could be explained by regressionl equations N level (% DW = -0.0099 × SPAD + 2.2366; R² = 0.91; N level (% DW = -0.0177 × SPAD + 2.8001; R² = 0.67; and N level (% DW = -0.0187 × SPAD + 2.7785; R² = 0.45 in young, middle-aged and old trees, respectively. It is suggested that the SPAD value determined by a portable chlorophyll meter can be used to obtain a quick estimation of mangosteen leaf N status. Keywords: age, fruiting position, Garcinia mangostana L., nitrogen, SPAD

  4. A leaf detection method using image sequences and leaf movement

    NARCIS (Netherlands)

    Hemming, J.; Henten, van E.J.; Tuijl, van B.A.J.; Bontsema, J.

    2005-01-01

    Besides harvesting the fruits, a very time demanding task is removing old leaves from cucumber and tomato plants grown in greenhouses. To be able to automate this process by a robot, a leaf detection method is required. One possibility for the detection is to exploit the different dynamic behaviour

  5. Origin of the Outbreak in France of Pseudomonas syringae pv. actinidiae Biovar 3, the Causal Agent of Bacterial Canker of Kiwifruit, Revealed by a Multilocus Variable-Number Tandem-Repeat Analysis

    Science.gov (United States)

    Cunty, A.; Cesbron, S.; Poliakoff, F.; Jacques, M.-A.

    2015-01-01

    The first outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 were detected in France in 2010. P. syringae pv. actinidiae causes leaf spots, dieback, and canker that sometimes lead to the death of the vine. P. syringae pv. actinidifoliorum, which is pathogenic on kiwi as well, causes only leaf spots. In order to conduct an epidemiological study to track the spread of the epidemics of these two pathogens in France, we developed a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). MLVA was conducted on 340 strains of P. syringae pv. actinidiae biovar 3 isolated in Chile, China, France, Italy, and New Zealand and on 39 strains of P. syringae pv. actinidifoliorum isolated in Australia, France, and New Zealand. Eleven polymorphic VNTR loci were identified in the genomes of P. syringae pv. actinidiae biovar 3 ICMP 18744 and of P. syringae pv. actinidifoliorum ICMP 18807. MLVA enabled the structuring of P. syringae pv. actinidiae biovar 3 and P. syringae pv. actinidifoliorum strains in 55 and 16 haplotypes, respectively. MLVA and discriminant analysis of principal components revealed that strains isolated in Chile, China, and New Zealand are genetically distinct from P. syringae pv. actinidiae strains isolated in France and in Italy, which appear to be closely related at the genetic level. In contrast, no structuring was observed for P. syringae pv. actinidifoliorum. We developed an MLVA scheme to explore the diversity within P. syringae pv. actinidiae biovar 3 and to trace the dispersal routes of epidemic P. syringae pv. actinidiae biovar 3 in Europe. We suggest using this MLVA scheme to trace the dispersal routes of P. syringae pv. actinidiae at a global level. PMID:26209667

  6. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  7. 7 CFR 28.423 - Middling Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Spotted Color. 28.423 Section 28.423... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Spotted Cotton § 28.423 Middling Spotted Color. Middling Spotted Color is color which is within the range represented by a set of samples in the custody...

  8. Land surface phenology from SPOT VEGETATION time series

    Directory of Open Access Journals (Sweden)

    A. Verger

    2016-12-01

    Full Text Available Land surface phenology from time series of satellite data are expected to contribute to improve the representation of vegetation phenology in earth system models. We characterized the baseline phenology of the vegetation at the global scale from GEOCLIM-LAI, a global climatology of leaf area index (LAI derived from 1-km SPOT VEGETATION time series for 1999-2010. The calibration with ground measurements showed that the start and end of season were best identified using respectively 30% and 40% threshold of LAI amplitude values. The satellite-derived phenology was spatially consistent with the global distributions of climatic drivers and biome land cover. The accuracy of the derived phenological metrics, evaluated using available ground observations for birch forests in Europe, cherry in Asia and lilac shrubs in North America showed an overall root mean square error lower than 19 days for the start, end and length of season, and good agreement between the latitudinal gradients of VEGETATION LAI phenology and ground data.

  9. LEAF: A Microcomputer Program for Constructing the Tukey Stem and Leaf Graph.

    Science.gov (United States)

    Pascale, Pietro J.; Smith, Joseph

    1986-01-01

    This paper presents a BASIC microcomputer program that constructs the Tukey (1977) stem and leaf graph. Options within the LEAF program include a modified stem and leaf where the stem is split and a parallel stem and leaf graph where two separate sets of data are displayed from a common stem. (Author)

  10. APPLICATION OF FOLIAR FERTILIZER AND FUNGICIDES ON WHITE SPOT DISEASE CONTROL AND DEVELOPMENT OF MAIZE

    Directory of Open Access Journals (Sweden)

    C. H. Brito

    2016-11-01

    Full Text Available This study aimed to evaluate the effect of forms of application of foliar fertilizers and fungicides to control fungus causing white maize spot, Phaeosphaeria maydis, and the growth and development of hybrids maize. The design had randomized blocks, with the use two sources hybrids maize with different reaction to white maize spot: resistant and susceptive and application with moisture of foliar chemical fungicide + cobalt foliar + molybdenum foliar + manganese and control treatment, without application consisting of four treatments and five replications. In the treatments with application of moisture were done on vegetative maize growth stage V8 (stage that determine that the number of kernel rows, VT (stage that arrives when the last branch of the tassel is completely visible and reproductive maize growth stage R2 (kernels are white on the outside and resemble a blister. The evaluation of variables of growth of maize plants: grain dry mass, cob dry mass, leaf dry mass, culm dry mass and modificated leaf ear and total plant dry mass. Harvest was carried out when the grains were 20% humidity. The application of fungicides and foliar fertilizers increased the leaves, culm, ear modificated, cobs and shoot dry mass plants maize. The application of fungicides and foliar fertilizers providing returning of 11.409,5 kg ha-1 of shoot dry mass plants with increased of 1.296 kg ha-1 on soil(12,81%. In the susceptive hybrid maize the application of fungicides and foliar fertilizers provide higher dry mass grains and shoot of plants.

  11. 7 CFR 29.2529 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole...

  12. 7 CFR 29.6022 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap...

  13. 7 CFR 29.3526 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from...

  14. 7 CFR 29.3034 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco...

  15. 7 CFR 29.3035 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See...

  16. 7 CFR 29.3527 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity....

  17. 7 CFR 29.6023 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by...

  18. 7 CFR 29.1030 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity....

  19. Comparison of half and full-leaf shape feature extraction for leaf classification

    Science.gov (United States)

    Sainin, Mohd Shamrie; Ahmad, Faudziah; Alfred, Rayner

    2016-08-01

    Shape is the main information for leaf feature that most of the current literatures in leaf identification utilize the whole leaf for feature extraction and to be used in the leaf identification process. In this paper, study of half-leaf features extraction for leaf identification is carried out and the results are compared with the results obtained from the leaf identification based on a full-leaf features extraction. Identification and classification is based on shape features that are represented as cosines and sinus angles. Six single classifiers obtained from WEKA and seven ensemble methods are used to compare their performance accuracies over this data. The classifiers were trained using 65 leaves in order to classify 5 different species of preliminary collection of Malaysian medicinal plants. The result shows that half-leaf features extraction can be used for leaf identification without decreasing the predictive accuracy.

  20. Superoscillating electron wave functions with subdiffraction spots

    Science.gov (United States)

    Remez, Roei; Tsur, Yuval; Lu, Peng-Han; Tavabi, Amir H.; Dunin-Borkowski, Rafal E.; Arie, Ady

    2017-03-01

    Almost one and a half centuries ago, Abbe [Arch. Mikrosk. Anat. 9, 413 (1873), 10.1007/BF02956173] and shortly after Lord Rayleigh [Philos. Mag. Ser. 5 8, 261 (1879), 10.1080/14786447908639684] showed that, when an optical lens is illuminated by a plane wave, a diffraction-limited spot with radius 0.61 λ /sinα is obtained, where λ is the wavelength and α is the semiangle of the beam's convergence cone. However, spots with much smaller features can be obtained at the focal plane when the lens is illuminated by an appropriately structured beam. Whereas this concept is known for light beams, here, we show how to realize it for a massive-particle wave function, namely, a free electron. We experimentally demonstrate an electron central spot of radius 106 pm, which is more than two times smaller than the diffraction limit of the experimental setup used. In addition, we demonstrate that this central spot can be structured by adding orbital angular momentum to it. The resulting superoscillating vortex beam has a smaller dark core with respect to a regular vortex beam. This family of electron beams having hot spots with arbitrarily small features and tailored structures could be useful for studying electron-matter interactions with subatomic resolution.