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Sample records for bacterial leaf blight

  1. Screening Rice Cultivars for Resistance to Bacterial Leaf Blight.

    Science.gov (United States)

    Fred, Agaba Kayihura; Kiswara, Gilang; Yi, Gihwan; Kim, Kyung-Min

    2016-05-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defenserelated genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals. PMID:26869604

  2. 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 Xa

  3. Capability of Streptomyces spp. in Controlling Bacterial Leaf Blight Disease in Rice Plants

    OpenAIRE

    Ratih D. Hastuti; Yulin Lestari2); Rasti Saraswati; Antonius Suwanto; Chaerani

    2012-01-01

    Problem statement: Bacterial Leaf Blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is the most damaging disease in lowland rice growing areas in Indonesia. Streptomyces spp. have been known as a producer of antimicrobial compounds that can be used as biocontrol agents. This study examined the ability of three promising indigenous Streptomyces isolates which were previously selected from in vitro agar media and greenhouse test to suppress natural infection of Xoo during dry and wet s...

  4. 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.

  5. Development of the variety for resistance against bacterial leaf-blight in rice with thermal neutrons

    International Nuclear Information System (INIS)

    In search for the development of genes for resistance against bacterial leaf-blight in rice, thermal neutrons generated from the Research Reactor at the Kyoto University have been applied to the breeding. In this paper, the developmental outcome is described, and a potential application of thermal neutrons for breeding the variety of resistance against bacterial leaf-blight in rice is reviewed. When thermal neutrons were delivered to the rice, the ratio of absorbed doses by B-10, which is contained in a small quantity in the plant, was found to be larger than expected. This implies characteristic effects of thermal neutrons on the plant. When boric acid was incorporated into the plant before irradiation, the effect of thermal neutrons per irradiation time was considered to become great. The frequency of mutations for resistance was significantly higher by thermal neutron, as compared with that induced by other mutagens, such as gamma radiation, ethylene-imine, ethyl-methane-sulfonate, and nitroso-methyl-urea. Genetic analysis of mutants for resistance revealed recessive genes and polygenes. Finally, the application of thermal neutrons and other radiations would contribute greatly to a resolution of serious pollution problems in global food and environment. (N.K.)

  6. Southern leaf blight disease severity is correlated with decreased maize leaf epiphytic bacterial species richness and the phyllosphere bacterial diversity decline is enhanced by nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Heather eManching

    2014-08-01

    Full Text Available Plant leaves are inhabited by a diverse group of microorganisms that are important contributors to optimal growth. Biotic and abiotic effects on plant growth are usually studied in controlled settings examining response to variation in single factors and in field settings with large numbers of variables. Multi-factor experiments with combinations of stresses bridge this gap, increasing our understanding of the genotype-environment-phenotype functional map for the host plant and the affiliated epiphytic community. The maize inbred B73 was exposed to single and combination abiotic and the biotic stress treatments: low nitrogen fertilizer and high levels of infection with southern leaf blight (causal agent Cochliobolus heterostrophus. Microbial epiphyte samples were collected at the vegetative early-season phase and species composition was determined using 16S ribosomal intergenic spacer analysis. Plant traits and level of southern leaf blight disease were measured late-season. Bacterial diversity was different among stress treatment groups (P< 0.001. Lower species richness—alpha diversity--was correlated with increased severity of southern leaf blight disease when disease pressure was high. Nitrogen fertilization intensified the decline in bacterial alpha diversity. While no single bacterial ribotype was consistently associated with disease severity, small sets of ribotypes were good predictors of disease levels. Difference in leaf bacterial-epiphyte diversity early in the season were correlated with plant disease severity, supporting further tests of microbial epiphyte-disease correlations for use in predicting disease progression.

  7. 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.

  8. Genetic analysis of the induced mutants of rice resistant to bacterial leaf blight

    International Nuclear Information System (INIS)

    Full text: Seeds of the rice cultivar 'Harebare', which is susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons, gamma-rays, ethyleneimine and ethylmethane-sulfonate. In the M2, plants with better resistance to BLB were identified through inoculation at the seedling and the flag leaf stages with an isolate (T7174) of the Japanese differential race I. Several mutant lines resistant to BLB were selected through tests of the M3 or M4 lines derived from selected resistant M2 plants. The frequency of resistant mutants was significantly higher after the thermal neutron treatment than after treatments with other mutagens. Two mutants, which originated from the neutron treatment, showing a highly quantitative resistance to multiple BLB races were analysed for gene(s) for resistance. The resistance of one of them (M41) to the Japanese races I, II, III, IV, and V was found to be conditioned by a single recessive gene. Three other recessive genes for resistance are known, but their reaction to differential races is different. Therefore, this gene was thought to be new and was tentatively designated as xa-nm(t). The resistance of another mutant (M57) was found to be polygenically inherited. (author)

  9. 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%.

  10. First report of bacterial leaf blight on mustard greens (Brassica juncea) caused by pseudomonas cannabina pv. alisalensis in Mississippi

    Science.gov (United States)

    In 2010, a brassica leafy greens grower in Sunflower County, Mississippi, observed scattered outbreaks of a leaf blight disease on mustard greens (Brassica juncea) in a 180-hectare field. A severe outbreak of leaf blight occurred on mustard greens and turnip greens (Brassica rapa) in the same field...

  11. Capability of Streptomyces spp. in Controlling Bacterial Leaf Blight Disease in Rice Plants

    Directory of Open Access Journals (Sweden)

    Ratih D. Hastuti

    2012-01-01

    Full Text Available Problem statement: Bacterial Leaf Blight (BLB caused by Xanthomonas oryzae pv. oryzae (Xoo is the most damaging disease in lowland rice growing areas in Indonesia. Streptomyces spp. have been known as a producer of antimicrobial compounds that can be used as biocontrol agents. This study examined the ability of three promising indigenous Streptomyces isolates which were previously selected from in vitro agar media and greenhouse test to suppress natural infection of Xoo during dry and wet season trials in 2009/2010 at the Muara Experimental Research Station, Bogor West Java, Indonesia. Approach: Streptomyces isolates (PS4-16, LBR-02 and LSW-05 were applied through seed coating in a peat-based carrier followed by seedling soaking, spray treatment, or combination of both methods, either singly or in combination of two or three isolates. The number of Streptomyces population in the peat carrier at the time of inoculation was above 107 cell g-1. The efficacy of Streptomyces was compared to that chemical spray using NORDOX 56 WP (a.i., zinc oxide 56% and non-treatment. Treated and untreated seeds were grown in plots (5×5 m2 and set in a randomized complete block design with four replications. Results: In the dry season experiment, application of Streptomyces spp. reduced BLB severity when compared to that of untreated plots, although did not reduce BLB incidence. PS4-16, applied singly through seed coating followed by seedling soaking, reduced the Area Under Disease Progress Curve (AUDPC at 70 Days After Planting (DAP to 1458, which was equally effective to the chemical spray (AUDPC value 1434 and simultaneously promoted plant height and gave the highest rice yield. In the wet season trial PS4-16 and LBR-02, applied singly or in dual combination through seed coating followed by seedling soaking, suppressed BLB severity, PS4-16 was confirmed as the most effective isolate by reducing the AUDPC to 1923, which was not significantly different to the

  12. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice

    OpenAIRE

    Sung-Il Kim; Jong Tae Song; Jin-Yong Jeong; Hak Soo Seo

    2016-01-01

    Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues...

  13. A new gene, developed through mutagenesis with thermal neutrons, for resistance of rice to bacterial leaf blight

    International Nuclear Information System (INIS)

    Dry seed lots of a rice variety, Harebare, susceptible to bacterial leaf blight (BLB), were treated with thermal neutrons with and without pre-treatment of the seeds by boron-enrichment, gamma-rays and nitroso-methyl-urea (NMU). The selections were made on M2-M3 materials by inoculation of Japanese BLB race III, with the result that several BLB resistant mutants to race III and the other differential races could be obtained. Mutagenic efficiency of thermal neutrons to the seeds without boron-enrichment for induction of BLB resistant mutants was found to be significantly higher than that of the other mutagens. Four mutant lines of all the selected ones were analyzed for genes for BLB resistance through cross tests between the mutants and the original variety. Harebare, indicating that the resistance in the mutants was conditioned by single recessive gene(s). The mutant designated 86M95 was especially noted for its gene conferring complete (or durable) resistance to multiple BLB races. The 86M95 mutant or the gene may be of practical value for breeding of rice for BLB resistance. (author)

  14. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice.

    Science.gov (United States)

    Kim, Sung-Il; Song, Jong Tae; Jeong, Jin-Yong; Seo, Hak Soo

    2016-01-01

    Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects. PMID:26879887

  15. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

    Science.gov (United States)

    Shi, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-06-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection. PMID:26948237

  16. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice

    OpenAIRE

    SHI, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-01-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metab...

  17. 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...

  18. 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.

  19. Close linkage of a blast resistance gene, Pias(t), with a bacterial leaf blight resistance gene, Xa1-as(t), in a rice cultivar ‘Asominori’

    Science.gov (United States)

    Endo, Takashi; Yamaguchi, Masayuki; Kaji, Ryota; Nakagomi, Koji; Kataoka, Tomomori; Yokogami, Narifumi; Nakamura, Toshiki; Ishikawa, Goro; Yonemaru, Jun-ichi; Nishio, Takeshi

    2012-01-01

    It has long been known that a bacterial leaf blight-resistant line in rice obtained from a crossing using ‘Asominori’ as a resistant parent also has resistance to blast, but a blast resistance gene in ‘Asominori’ has not been investigated in detail. In the present study, a blast resistance gene in ‘Asominori’, tentatively named Pias(t), was revealed to be located within 162-kb region between DNA markers YX4-3 and NX4-1 on chromosome 4 and to be linked with an ‘Asominori’ allele of the bacterial leaf blight resistance gene Xa1, tentatively named Xa1-as(t). An ‘Asominori’ allele of Pias(t) was found to be dominant and difference of disease severity between lines having the ‘Asominori’ allele of Pias(t) and those without it was 1.2 in disease index from 0 to 10. Pias(t) was also closely linked with the Ph gene controlling phenol reaction, suggesting the possibility of successful selection of blast resistance using the phenol reaction. Since blast-resistant commercial cultivars have been developed using ‘Asominori’ as a parent, Pias(t) is considered to be a useful gene in rice breeding for blast resistance. PMID:23341747

  20. Research Progress on Northern Leaf Blight in Corn

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yingnan; WANG Zhenhua

    2009-01-01

    The northern corn leaf blight is one of the most serious diseases in maize production. The research progress on etiology, generation law and control strategy, antigen identification, resistance mechanism and inheritance of this disease was discussed. And the research work which should be enhanced in China was pointed out, such as mechanism of resistance inheritance, developing function marker, gene mining, screening resistance resource and dominant physiological race in different areas.

  1. 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.

  2. Resistance of Antimicrobial Peptide Gene Transgenic Rice to Bacterial Blight

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WU Chao; LIU Mei; LIU Xu-ri; Hu Guo-cheng; SI Hua-min; SUN Zong-xiu; LIU Wen-zhen; Fu Ya-ping

    2011-01-01

    Antimierobial peptide is a polypeptide with antimicrobial activity.Antimicrobial peptide genes Np3 and Np5 from Chinese shrimp (Fenneropenaeus Chinensis) were integrated into Oryza sativa L.subsp.japonica cv.Aichi ashahi by Agrobacterium mediated transformation system.PCR analysis showed that the positive ratios of Np3 and Np5 were 36% and 45% in T0 generation,respectively.RT-PCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation,and there was no obvious difference in agronomic traits between transgenic plants and non-transgenic plants.Four Np3 and Np5 transgenic lines in T1 generation were inoculated with ×anthomonas oryzae pv.oryzae strain CR4,and all the four transgenic lines had significantly enhanced resistance to bacterial blight caused by the strain CR4.The Np5 transgenic lines also showed higher resistance to bacterial blight caused by strains JS97-2,Zhe 173 and OS-225.It is suggested that transgenic lines with Np5 gene might possess broad spectrum resistance to rice bacterial blight.

  3. Primary study on the resistance to bacterial blight (X. oryzae) in Cecropin B gene transgenic rices

    Institute of Scientific and Technical Information of China (English)

    HUAZhihua; HUANGDanian; XUERui; WANGXiaoling; GAOZhenya

    1998-01-01

    Bacterial blight (BB) is one of the major diseases to rice. Antibacterial Cecropin B gene has been cloned and transformed into rice. We studied the resistance to bacterial blight in Cecropin B gene tronsgenic rices.

  4. Controlling rice bacterial blight in Africa : needs and prospects

    OpenAIRE

    Verdier, Valérie; Cruz, C.V.; Leach, J. E.

    2012-01-01

    Rice cultivation has drastically increased in Africa over the last decade. During this time, the region has also seen a rise in the incidence of rice bacterial blight caused by the pathogen Xanthomonas oryzae pv. oryzae. The disease is expanding to new rice production areas and threatens food security in the region. Yield losses caused by X. oryzae pv. oryzae range from 20 to 30% and can be as high as 50% in some areas. Employing resistant cultivars is the most economical and effective way to...

  5. Sustainable control of pea bacterial blight : approaches for durable genetic resistance and biocontrol by endophytic bacteria

    NARCIS (Netherlands)

    Elvira-Recuenco, M.

    2000-01-01

    Key-words: bacterial blight, biological control, biodiversity, endophytic bacteria, L-form, pea, PDRl retrotransposon, Pisum sativum, Pisum abyssinicum, Pseudomonas syringae pv. pisi, race specific resistance, race non-specific resistance, Spanish landraces.Pea bacterial blight (Pseudom

  6. Development of a weather-based model for Botrytis leaf blight of onion

    OpenAIRE

    Leandro Luiz Marcuzzo; Roberto Haveroth

    2016-01-01

    ABSTRACT In the present study, onion plants were tested under controlled conditions for the development of a climate model based on the influence of temperature (10, 15, 20 and 25°C) and leaf wetness duration (6, 12, 24 and 48 hours) on the severity of Botrytis leaf blight of onion caused by Botrytis squamosa. The relative lesion density was influenced by temperature and leaf wetness duration (P

  7. Neofusicoccum ribis Associated with Leaf Blight on Rubber (Hevea brasiliensis in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    A. I. C. Nyaka Ngobisa

    2013-03-01

    Full Text Available Hevea brasiliensis is a natural source of rubber and an important plantation tree species in Malaysia. Leaf blight disease caused by Fusicoccum substantially reduces the growth and performance of H. brasiliensis. The aim of this study was to use a combination of both morphological characteristics and molecular data to clarify the taxonomic position of the fungus associated with leaf blight disease. Fusicoccum species were isolated from infected leaves collected from plantations at 3 widely separated locations – Selangor, Perak, and Johor states – in Peninsular Malaysia in 2010. All the isolates were identified according to their conidial patterns and DNA sequences generated from internal transcribed spacers (ITS1 and ITS2, the 5.8S rRNA, and an unknown locus (BotF15 containing microsatellite repeats. Based on taxonomic and sequence data, Neofusicoccum ribis was identified as the main cause of leaf blight disease in H. brasiliensis in commercial plantations in Malaysia. A pathogenicity trial on detached leaves further confirmed that N. ribis causes leaf blight disease. N. ribis is an important leaf pathogen, and its detection in Malaysia has important implications for future planting of H. brasiliensis.

  8. Development of a weather-based model for Botrytis leaf blight of onion

    Directory of Open Access Journals (Sweden)

    Leandro Luiz Marcuzzo

    2016-03-01

    Full Text Available ABSTRACT In the present study, onion plants were tested under controlled conditions for the development of a climate model based on the influence of temperature (10, 15, 20 and 25°C and leaf wetness duration (6, 12, 24 and 48 hours on the severity of Botrytis leaf blight of onion caused by Botrytis squamosa. The relative lesion density was influenced by temperature and leaf wetness duration (P <0.05. The disease was most severe at 20°C. Data were subjected to nonlinear regression analysis. Beta generalized function was used to adjust severity and temperature data, while a logistic function was chosen to represent the effect of leaf wetness on the severity of Botrytis leaf blight. The response surface obtained by the product of two functions was expressed as ES = 0.008192 * (((x-51.01089 * ((30-x1.19052 * (0.33859/(1+3.77989 * exp (-0.10923*y, where ES represents the estimated severity value (0.1; x, the temperature (°C; and y, the leaf wetness (in hours. This climate model should be validated under field conditions to verify its use as a computational system for the forecasting of Botrytis leaf blight in onion.

  9. Performance of resistance gene pyramids to races of rice bacterial blight in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    ZHENGKangle; ZHUANGJieyun; WANGHanrong

    1998-01-01

    The effect of gene pyramiding on resistance to bacterial blight (BB) in rice was evahlated among the IR24-based near isogenic lines conraining single resistance gene and gene pyramids containing two, three or lour resistancegenes (see table).

  10. 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

  11. 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.

  12. TURCICUM LEAF BLIGHT OF MAIZE INCITED BY Exserohilum turcicum: A REVIEW

    Directory of Open Access Journals (Sweden)

    T. Rajeshwar Reddy

    2014-03-01

    Full Text Available Globally maize (Zea mays L. is the first and most important cereal crop gown under diversity of environments unmatched by any other crop, as expansion of maize to new areas and environment still continues due to its range of plasticity. It is prone to as many as 112 diseases in different parts of the world, caused by fungi, bacteria, viruses and nematodes leading to extensive damage. In India about 61 diseases have been reported to affect the crop. These include seedling blights, stalk rots, foliar diseases, downy mildews and ear rots (Payaket al., 1973 and Payak and Sharma, 1985.Among the fungal diseases turcicum leaf blight caused by Exserohilum turcicum (Pass.. Leonard and Suggs. (Synonyms:Helminthosprium turcicum (Pass. Leonard and Suggs [Perfect stage: Setosphaeria turcica (Luttrell Leonard and Suggs. (Synonym: Trichometasphaeria turcica (Luttrell] is one the important foliar disease causing severe reduction in grain and fodder yield to the tune of 16 -98% (Kachapur and Hegde, 1988. The disease was first described by Passerini (1876 from Italy and by Butler (1907 from India. In India, this disease is prevalent in Andhra Pradesh, Karnataka, Bihar, Himachal Pradesh and Maharashtra. Turcicum leaf blight is potentially an important foliar disease in areas where the temperatures drop at night while the humidity is high. The disease is known to affect maize from seedling stage till harvest. Loss in grain yield will be more if it occurs at flowering, silking and grain filling stages. Lesions produced on the leaves of susceptible plants are normally large (4 -20 cm long and 1-5 cm wide, elliptical in shape and greyish green to tan in color, in conditions of high relative humidity, lesions may be covered with masses of dark conidia of the fungus. The conidia are olive grey and spindle shaped with 1- 9 septations. These conidia spread through air germinate on the surface and penetrate directly. Turcicum blight injures or kills the leaf tissues and

  13. Inheritance of resistance to bacterial streak and hacterial blight in rice

    Institute of Scientific and Technical Information of China (English)

    XUJianlong; WANGHanrong; LINYi; XIYongan

    1998-01-01

    Bacterial streak(BS) caused by Xanthomonas campesiris pv. oryzicola bas become one of the major diseases in southbern rice areas.Up to date, tbere are few reports on the inheritance of resistance to BS and its relationsbip with the resistance to bacterial blight(BB).

  14. Tagging RAPD markers to a bacterial blight resistance gene in rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The somaclonal mutant HX_3 has shown a broad spectrum resistance to bacterial blight. To study the inheritance of the bacterial blight resistance in HX_3, a cross was made between HX_3 and a susceptible cultivar Longtefu A. The F2 population of 418 plants was inoculated with Chinese bacterial blight strain Zhe 173 (pathotype Ⅳ ). Results showed that the F2 progenies segregated in a ratio of 3R∶ 1S (324 resistant plants and 94 susceptible plants). From the plants tested, 114 individuals (86 resistant and 28 susceptible) were chosen randomly for RAPD analysis. Twelve highly resistant and 12 highly susceptible plants were selected to form a resistant pool and a susceptible pool, respectively.

  15. Occurrence of Leaf Blight on Cosmos Caused by Alternaria cosmosa in Korea

    Directory of Open Access Journals (Sweden)

    Jian Xin Deng

    2015-03-01

    Full Text Available In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea.

  16. Occurrence of Leaf Blight on Cosmos Caused by Alternaria cosmosa in Korea.

    Science.gov (United States)

    Deng, Jian Xin; Lee, Ji Hye; Paul, Narayan Chandra; Cho, Hye Sun; Lee, Hyang Burm; Yu, Seung Hun

    2015-03-01

    In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus) leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea.

  17. Integrated Control of Fire Blight with Bacterial Antagonists and Oxytetracycline

    Science.gov (United States)

    In the Pacific Northwest of the United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of Erwinia amylovora were prevalent. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the duration of inhibitory acti...

  18. Differential responses to pea bacterial blight in stems, leaves and pods under glasshouse and field conditions

    NARCIS (Netherlands)

    Elvira-Recuenco, M.; Bevan, J.R.; Taylor, J.D.

    2003-01-01

    Resistance to pea bacterial blight (Pseudomonas syringae pv. pisi) in different plant parts was assessed in 19 Pisum sativum cultivars and landraces, carrying race-specific resistance genes (R-genes) and two Pisum abyssinicum accessions carrying race-nonspecific resistance. Stems, leaves and pods we

  19. Identification of markers associated with bacterial blight resistance loci in cowpea (Vigna unguiculata (L.) Walp.)

    NARCIS (Netherlands)

    Agbicodo, A.C.M.E.; Fatokun, C.A.; Bandyopadhyay, R.; Wydra, K.; Diop, N.N.; Muchero, W.; Ehlers, J.D.; Roberts, P.A.; Close, T.J.; Visser, R.G.F.; Linden, van der C.G.

    2010-01-01

    Cowpea bacterial blight (CoBB), caused by Xanthomonas axonopodis pv. vignicola (Xav), is a worldwide major disease of cowpea [Vigna unguiculata (L.) Walp.]. Among different strategies to control the disease including cultural practices, intercropping, application of chemicals, and sowing pathogen-fr

  20. Complete genome sequence of Japanese erwinia strain ejp617, a bacterial shoot blight pathogen of pear.

    Science.gov (United States)

    Park, Duck Hwan; Thapa, Shree Prasad; Choi, Beom-Soon; Kim, Won-Sik; Hur, Jang Hyun; Cho, Jun Mo; Lim, Jong-Sung; Choi, Ik-Young; Lim, Chun Keun

    2011-01-01

    The Japanese Erwinia strain Ejp617 is a plant pathogen that causes bacterial shoot blight of pear in Japan. Here, we report the complete genome sequence of strain Ejp617 isolated from Nashi pears in Japan to provide further valuable insight among related Erwinia species.

  1. 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.

  2. Stemphylium Leaf Blight of Garlic (Allium sativum in Spain: Taxonomy and In Vitro Fungicide Response

    Directory of Open Access Journals (Sweden)

    Laura Gálvez

    2016-10-01

    Full Text Available The most serious aerial disease of garlic is leaf blight caused by Stemphylium spp. Geographical variation in the causal agent of this disease is indicated. Stemphylium vesicarium has been reported in Spain, whereas S. solani is the most prevalent species recorded in China. In this study, Stemphylium isolates were obtained from symptomatic garlic plants sampled from the main Spanish production areas. Sequence data for the ITS1–5.8S–ITS2 region enabled assignation of the isolates to the Pleospora herbarum complex and clearly distinguished the isolates from S. solani. Conidial morphology of the isolates corresponded to that of S. vesicarium and clearly discriminated them from S. alfalfae and S. herbarum on the basis of the size and septation pattern of mature conidia. Conidial morphology as well as conidial length, width and length:width ratio also allowed the Spanish isolates to be distinguished from S. botryosum and S. herbarum. Control of leaf blight of garlic is not well established. Few studies are available regarding the effectiveness of chemical treatments to reduce Stemphylium spp. incidence on garlic. The effectiveness of nine fungicides of different chemical groups to reduce Stemphylium mycelial growth in vitro was tested. Boscalid + pyraclostrobin (group name, succinate dehydrogenase inhibitors + quinone outside inhibitors, iprodione (dicar-boximide, and prochloraz (demethylation inhibitors were highly effective at reducing mycelial growth in S. vesicarium with EC₅₀ values less than 5 ppm. In general, the effectiveness of the fungicide was enhanced with increasing dosage.

  3. Improvement of Resistance to Bacterial Blight by Marker-Assisted Selection in a Wide Compatibility Restorer Line of Hybrid Rice

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiu-hua; LUO Yan-chang; LIU Qiao-quan; WANG Shou-hai; WU Hsin-kan; LI Cheng-quan; WANG Zong-yang; WU Shuang; GU Ming-hong; WANG De-zheng; DU Shi-yun

    2004-01-01

    4183 is a promising wide compatibility restorer line with good grain quality. Its hybrid rice Shuangyou 4183 (Shuangjiu A/4183) was registered in Anhui Province in 2003. However, the line and its hybrid rice are susceptible to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). R4183 carrying Xa21 was developed to improve bacterial blight resistance of 4183 through introducing the broad-spectrum resistance gene Xa21 by marker-aided selection. R4183 had similar level of bacterial blight resistance to IRBB21, the resistant donor, while maintained the wide compatibility, restoring ability and other good economic traits of the recurrent parent 4183. Critical issues on improvement of bacterial blight resistance of hybrid rice and breeding strategies were also discussed.

  4. Pathogenic reaction of some introduced rice cultivars (lines) to seven pathotypes of bacterial blight in Hangzhou

    Institute of Scientific and Technical Information of China (English)

    SHENYing; ZHUPeiliang; YUANXiaoping

    1993-01-01

    Bacterial blight (BB) caused by Xanthomonas oryzae pv.oryzae (Xoo) is a major rice disease in China. 138 introduced cultivars (lines) were tested on pathogenicity with seven pathotypes of BB at CNRRI Experiment Station during Apt-Oct,1991.

  5. ECONOMIC EVALUATION OF FUNGICIDE APPLICATION ON TARO (Colocasia esculenta LEAF BLIGHT

    Directory of Open Access Journals (Sweden)

    Tarla D N

    2014-05-01

    Full Text Available Taro is an important crop in Cameroon but yields of the crop has severely affected by pests and diseases especially leaf blight. An economic evaluation of fungicide applications on taro blight was conducted in Dschang, Cameroon, during the 2012 cropping season. A split-plot design was used, with two factors; fungicide and cultivar, replicated three times. Whole plots were assigned to five fungicide spray schedules (7, 14, 21, 28-day, and non-treated while sub-plots were assigned to two taro cultivars; the dark green petioles (“Ibo coco” cultivar and the light green petioles small leaves (“Ehkoueh’lah” cultivar. A fungicide, Plantomil 72 WP was applied at 3.33 kgha-1 . Blight severity was scored weekly in every sub-plot, and yields were obtained at harvest. Data was subjected to the analysis of variance. Standardized area under disease progress curve (SAUDPC was high (p = 0.005 in control plots compared to sprayed plots of the cultivars. The high SAUDPC values were correlated with low yields (16.11 t/ha in control plots of “Ibo coco” compared to high yields (60.44 to 62.11 t/ha in sprayed plots. For “Ehkoueh’lah”, yield differences between control and sprayed plots were not high, 33.11 tha-1 in the control compared to 46.83 to 49.06 tha-1 in sprayed plots. The highest yield increase of 74.06 and 32.51 % for “Ibo coco” and “Ehkoueh’lah”, respectively was obtained from 7-day sprayed plots. Economic analysis revealed that a 28-day fungicide spray frequency had the highest rate of return, 13.78 and 6.63 and net benefits of 8.26 and 4.76 million FCFAha-1 for “Ibo coco” and “Ehkoueh’lah”, respectively. Thus, taro leaf blight can be managed with monthly applications of fungicide.

  6. Genetics and Improvement of Bacterial Blight Resistance of Hybrid Rice in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi

    2009-01-01

    Since 1980s, rice breeding for resistance to bacterial blight has been rapidly progressing in China. The gene Xa4 was mainly used in three-line indica hybrid and two-line hybrid rice. The disease has been 'quiet' for 20 years in China, yet in recent years it has gradually emerged and been prevalent in fields planted with newly released rice varieties in the Changjiang River valley. Under the circumstances, scientists inevitably raised several questions: what causes the resurgence and what should we do next? And/or is resistance breeding still one of the main objectives in rice improvement? Which approach do we take on resistance breeding so that the resistance will be more durable, and the resistance gene will be used more efficiently? A combined strategy involving traditional method, molecular marker-assisted selection, and transgenic technology should bring a new era to the bacterial blight resistance hybrid rice breeding program. This review also briefly discusses and deliberates on issues related to the broadening of bacterial blight resistance, and suitable utilization of resistance genes, alternate planting of available resistance genes; and understands the virulent populations of the bacterial pathogen in China even in Asia.

  7. 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.

  8. Combining ability of Phaseolus vulgaris L. for resistance to common bacterial blight

    Directory of Open Access Journals (Sweden)

    Rosana Rodrigues

    1999-12-01

    Full Text Available Many diseases limit dry bean and snap bean yields. Common bacterial blight (CBB, caused by Xanthomonas axonopodis pv. phaseoli, is one of the most serious bacterial diseases in dry bean and snap bean that cause crop losses. Since there is no satisfactory chemical control, the use of resistant cultivars is an important control measure. Genetic studies of resistance are important for choosing appropriate breeding methods. Combining ability was determined for disease resistance in three snap bean genotypes (Alessa, Hab 52 and Hab 198 and two dry bean genotypes (Bac-6 and A-794. Plants were inoculated with highly pathogenic isolate CNF 15, using a razor blade procedure in leaves and needle punctures in pods. They were evaluated 7 days after inoculation. Leaves were evaluated on a 1 to 5 scale and pods by lesion diameter. Diallel analysis was conducted using Griffing's model. General combining ability (GCA was significant for both leaf and pod infection, whereas specific combining ability (SCA was significant for disease reaction in pods. Bac-6 and A-794 were considered superior genotypes for leaf resistance. Nonadditive effects were predominant in pod reactions, and Alessa x Bac-6, Alessa x A-794 and Hab 52 x Bac-6 were the best combinations.Entre as várias doenças que causam problemas às culturas do feijão-de-vagem e do feijão comum, uma das mais importantes é o crestamento bacteriano comum (CBB, causado pela bactéria Xanthomonas axonopodis pv. phaseoli, que pode ocasionar grandes perdas na produção. O controle químico não é eficiente, e entre as medidas de controle recomendadas, destaca-se a resistência genética. Estudos genéticos da resistência são básicos para a definição dos métodos de melhoramento a serem adotados para cada caso. Avaliou-se a capacidade de combinação de três genótipos de feijão-de-vagem (Alessa, Hab 52, Hab 198 e dois de feijão comum (Bac-6 e A-794 quanto à resistência ao CBB, em folhas e vagens. A

  9. [Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].

    Science.gov (United States)

    Tovkach, F I; Moroz, S N; Korol', N A; Faĭdiuk, Iu V; Kushkina, A I

    2013-01-01

    Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants.

  10. Research Status and Prospect ofBurkholderia glumae, the Pathogen Causing Bacterial Panicle Blight

    Institute of Scientific and Technical Information of China (English)

    CUI Zhou-qi; ZHU Bo; XIE Guan-lin; LI Bin; HUANG Shi-wen

    2016-01-01

    Bacterial panicle blight caused by Burkholderia glumae is one of the most severe seed-borne bacterial diseases of rice in the world. Currently, this disease has affected many countries of Asia, Africa, South and North America. It is a typical example of the shifting from minor plant disease to major disease due to the changes of environmental conditions. Some virulent factors of B. glumae have been identified, including toxoflavins and lipases, whose productions are dependent on the TofI/TofR quorum-sensing system, and type III effectors. In spite of its economic significance, neither effective control measure for this disease nor resistant rice variety is currently available. In recent years, genomics, transcriptomics and other molecular methods have provided useful information for better understanding the molecular mechanisms underlyingB. glumaevirulence and the rice defence mechanisms against pathogens. For the prevention of this pathogen, our laboratory has developed a rapid and sensitive multiplex PCR assay for detecting and distinguishingB. glumae from otherBurkholderia species. This improved understanding ofB. glumae will shed new light on bacterial panicle blight disease management.

  11. Controlling Botrytis elliptica Leaf Blight on Hybrid Lilies through the Application of Convergent Chemical X-ray Irradiation

    Directory of Open Access Journals (Sweden)

    Sung-Jun Hong

    2016-04-01

    Full Text Available X-ray irradiation with convergent chemicals such as nano-silver particles or sodium dichloroisocyanurate (NaDCC has been used to control leaf blight on cut lilies. The oriental hybrid lily cultivars Siberia, Le Reve, and Sorbonne were irradiated five times by 200 Gy of X-rays in 2014. In 2015, Siberia and Sorbonne were irradiated three times by 150 Gy of X-rays. After artificial infection with Botrytis elliptica on the leaves and petals of cut lilies, this study used convergent chemical X-ray irradiation of 200 Gy or 150 Gy. Leaf and petal blight was measured in terms of incidence and severity at 8 days after infection using total 552 cuttings. Results indicate that the treatments of X-ray irradiation and NaDCC in 2014 and 2015 slightly decreased the severity of petal blight on Siberia and Sorbonne. However, the results were not significant and severity did not decrease as NaDCC concentration increased. Vase-life was observed separately after X-ray irradiation of 270 cut lilies in 2014 and 108 cut lilies in 2015. Chlorophyll content was not affected by either 200 Gy or 150 Gy of X-rays. The number of days of fully opened flowers at Siberia of 150 Gy and Le Revu of 200 Gy increased by 1–2 days. In addition, the relative fresh weights of the X-rayed flowers were 10% drier than the non-irradiated controls. Overall, leaf blight control by X-ray was inferior to the control by gamma rays, and petal color was bleached in Sorbonne and Le Reve cvs. by 150 Gy of X-rays.

  12. Controlling Botrytis elliptica Leaf Blight on Hybrid Lilies through the Application of Convergent Chemical X-ray Irradiation.

    Science.gov (United States)

    Hong, Sung-Jun; Koo, Tae-Hoon; Yun, Sung-Chul

    2016-04-01

    X-ray irradiation with convergent chemicals such as nano-silver particles or sodium dichloroisocyanurate (NaDCC) has been used to control leaf blight on cut lilies. The oriental hybrid lily cultivars Siberia, Le Reve, and Sorbonne were irradiated five times by 200 Gy of X-rays in 2014. In 2015, Siberia and Sorbonne were irradiated three times by 150 Gy of X-rays. After artificial infection with Botrytis elliptica on the leaves and petals of cut lilies, this study used convergent chemical X-ray irradiation of 200 Gy or 150 Gy. Leaf and petal blight was measured in terms of incidence and severity at 8 days after infection using total 552 cuttings. Results indicate that the treatments of X-ray irradiation and NaDCC in 2014 and 2015 slightly decreased the severity of petal blight on Siberia and Sorbonne. However, the results were not significant and severity did not decrease as NaDCC concentration increased. Vase-life was observed separately after X-ray irradiation of 270 cut lilies in 2014 and 108 cut lilies in 2015. Chlorophyll content was not affected by either 200 Gy or 150 Gy of X-rays. The number of days of fully opened flowers at Siberia of 150 Gy and Le Revu of 200 Gy increased by 1-2 days. In addition, the relative fresh weights of the X-rayed flowers were 10% drier than the non-irradiated controls. Overall, leaf blight control by X-ray was inferior to the control by gamma rays, and petal color was bleached in Sorbonne and Le Reve cvs. by 150 Gy of X-rays. PMID:27147927

  13. Fungicide baseline for mycelial sensitivity of Exserohilum turcicum, causal agent of northern corn leaf blight

    Directory of Open Access Journals (Sweden)

    Roberto Luis De Rossi

    2015-03-01

    Full Text Available Northern corn leaf blight, caused by Exserohilum turcicum (Et, is one of the major corn diseases which can reduce grain yield and quality. The aim of this study was to determine the mycelial sensitivity of ten Et isolates, five from Argentina and five from Brazil, to six fungicides (carbendazim, captan, fludioxinil, metalaxyl, iprodione and thiram used in seed treatment. The inhibitory concentration (IC50 was determined by using seven concentrations of the fungicides supplemented to the agar medium. The mycelial colony diameter was measured with a digital caliper. Experimental design was completely randomized with four replicates. Data on the percent mycelial growth inhibition were analyzed by logarithmic regression and the IC50 was calculated. The fungicide iprodione was the most potent, with IC50 50 mg/L for all isolates. Although iprodione is the most potent fungicide, it is not used for corn seed treatment. The IC50s obtained in this study can be used as baseline for future monitoring studies of Et sensitivity to fungicides.

  14. Leaf blight and defoliation of Eugenia spp. caused by Cylindrocladium candelabrum and C. spathiphylli in Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Sebastião Poltronieri

    2011-06-01

    Full Text Available Leaf blight and defoliation of Eugenia stipitata Mc Vaugh and Eugenia patrisii Vahl, caused respectively by Cylindrocladium candelabrum (Calonectria scoparia and C. spathiphylli (Calonectria spathiphylli are reported in the state of Pará, Brazil. On both host species, the disease is characterized by dark brown lesions of different sizes and shapes. A whitish bright sporulation, resembling Cylindrocladium is observed on the necrotic lesions by using a stereomycroscope or a pocket lense (10-20 X. Under favorable conditions and depending on the level of infection, intense premature tree defoliation may also be found.Although the conidial germination and mycelial growth were higher at 25ºC for both species, C. candelabrum was more sensitive to the variation of temperature (10, 20, 30 and 40 ºC than C. spathiphylli. This is the first report of C. candelabrum and C. spathiphylli on Eugenia stipitata (araçá-boi and on Eugenia patrisii (ubaia-da-amazônia, respectively in Brazil.

  15. Transgenic Rice Plants Harboring Genomic DNA from Zizania latifolia Confer Bacterial Blight Resistance

    Institute of Scientific and Technical Information of China (English)

    SHEN Wei-wei; SONG Cheng-li; CHEN Jie; Fu Ya-ping; Wu Jian-li; JIANG Shao-mei

    2011-01-01

    Based on the sequence of a resistance gene analog FZ14 derived from Zizania latifolia (Griseb.),a pair of specific PCR primers FZ14P1/FZ14P2 was designed to isolate candidate disease resistance gene.The pooled-PCR approach was adopted using the primer pair to screen a genomic transformation-competent artificial chromosome (TAC) library derived from Z.latifolia.A positive TAC clone (ZR1) was obtained and confirmed by sequence analysis.The results indicated that ZR1 consisted of conserved motifs similar to P-loop (kinase 1a),kinase 2,kinase 3a and GLPL (Gly-Leu-Pro-Leu),suggesting that it could be a portion of NBS-LRR type of resistance gene.Using Agrobacterium-mediated transformation of Nipponbare mature embryo,a total of 48 independent transgenic T0 plants were obtained.Among them,36 plants were highly resistant to the virulent bacterial blight strain P×O71.The results indicate that ZR1 contains at least one functional bacterial blight resistance gene.

  16. Complete Genome Sequence of Japanese Erwinia Strain Ejp617, a Bacterial Shoot Blight Pathogen of Pear ▿

    OpenAIRE

    Park, Duck Hwan; Thapa, Shree Prasad; Choi, Beom-Soon; Kim, Won-Sik; Hur, Jang Hyun; Cho, Jun Mo; Lim, Jong-Sung; Choi, Ik-Young; Lim, Chun Keun

    2010-01-01

    The Japanese Erwinia strain Ejp617 is a plant pathogen that causes bacterial shoot blight of pear in Japan. Here, we report the complete genome sequence of strain Ejp617 isolated from Nashi pears in Japan to provide further valuable insight among related Erwinia species.

  17. Bacterial blight (Pseudomonas pisi Sackett) of peas in South Africa, with special reference to frost as a predisposing factor

    NARCIS (Netherlands)

    Boelema, B.H.

    1972-01-01

    In the beginning of the nineteen fifties bacterial blight caused much damage to pea crops in South Africa, particularly to those grown for seed production. A study has been made of the causal organism and the conditioning factors of the disease, special attention being paid to frost as a predisposin

  18. Cloning of a peroxidase gene from cassava with potential as a molecular marker for resistance to bacterial blight

    OpenAIRE

    Luiz Filipe Pereira; Goodwin, Paul H.; Larry Erickson

    2003-01-01

    Cassava bacterial blight (CBB), caused by Xanthomonas axonopodis pv. manihotis, is considered one of the most important bacterial diseases of cassava (Manihot esculenta Crantz). In order to characterize the cassava genes involved in resistance to this disease, a genomic clone of a cationic peroxidase gene, MEPX1, was isolated by PCR from cassava cultivar MCOL 22. The DNA sequence of MEPX1 showed high homology with other plant peroxidase genes and contained a large intron typical of peroxidase...

  19. Gene expression analysis during cassava defense response to bacterial blight disease

    Directory of Open Access Journals (Sweden)

    Soto-Suárez Mauricio

    2006-12-01

    Full Text Available Cassava bacterial blight (CBB caused by Xanthomonas axonopodis pv. manihotis (Xam is a destructive disease in the South América and África and yield losses range between 12 and 100%. Cytochemistry and biochemistry of defense response to CBB have been well studied. However, the response of the plant to pathogen attack at the molecular and cellular level remains uncharacterized. Identification of genes associated with defense responses is one of most critical steps leading to the elucidation of disease resistance mechanisms in cassava. In this study, we identified differentially expressed genes during pathogen attack by subtractive hybridization, using the Differential Subtraction Chain method (DSC. A population of cDNA obtained from infected plants was used as ";treatment"; and a population of cDNA obtained from healthy plants was used as ";control";. 1536 clones were isolated from the resistant varieties (MBRA 685 and SG 107-35. Of these, 110 randomly selected clones were sequenced and a homology search was conducted. The sequence analysis showed that 14 cDNA clones shared homology with plant genes involved in defense responses, 70 clones were either homologous to plant genes of unknown function or showed no homology, representing new genes potentially involved in cassava defense responses. A cDNA microarray was constructed by spotting the clones identified from our subtractive libraries. Other clones potentially involved in cassava defense responses were also included. The cassava defense cDNA microarray was used to confirm the differential expression of the clones. Keywords: cassava, bacterial blight, gene expression, subtractive library, microarrays.

  20. 芋瘟的发生与综合防治措施%Occurrence and integrated control measures of taro leaf blight

    Institute of Scientific and Technical Information of China (English)

    王桂华

    2012-01-01

    芋瘟是南平市延平市芋头生产中最主要的一种病害,严重影响芋头种植业的发展。该文分析芋瘟的发病症状及发病规律,并总结其综合防治措施。%Leaf blight is one of the main diseases in taro production in Yanping District of Nanping City, it affects seriously the development of taro industry. The disease symptom and occurrence regularity of taro leaf blight were analysed and some integrated control measures were summarized in this paper.

  1. Quantitative analysis of resistance in cotton to three new isolates of the bacterial blight pathogen.

    Science.gov (United States)

    Wallace, T P; El-Zik, K M

    1990-04-01

    Genetic variability for virulence of the bacterial blight pathogen [Xanthomonas campestris pv malvacearum (Smith) Dye] on cotton (Gossypium hirsutum L.) has been shown by the identification of 19 races of the pathogen based on disease reactions of a set of ten host differentials. This study was conducted to determine the inheritance of host resistance to three recently identified isolates of X. campestris pv malvacearum, which are virulent on the entire set of differentials. True leaves of Tamcot CAMD-E, LEBOCAS-3-80, Stoneville 825, and their f1, F2, and backcross progenies were wound-inoculated in the field with separate bacterial suspensions of the virulent HV3, HV7, and Sudan isolates of the pathogen. LEBOCAS-3-80 was replaced with S295, a new immune cultivar, for a greenhouse study in which both cotyledons and true leaves were inoculated. Disease reactions were rated on a scale of 1-10, and genetic models were proposed utilizing generation means analysis. Dominance, when significant, was in the direction of resistance in all but one cross-isolate combination. Digenic interaction components indicated a duplicate type. Narrow-sense heritability for resistance ranged from 0.59 to 0.68; therefore, primarily additive-genetic variability among the selected cutlivars was detected, indicating that breeding for improved resistance to these isolates is a practical goal.

  2. Combining ability for common bacterial blight resistance in snap and dry bean (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    Roberto dos Santos Trindade

    2014-11-01

    Full Text Available Common bacterial blight (CBB, which is caused by Xanthomonas axonopodis pv. phaseoli (Xap, is the main bacterial disease in snap beans and controlling this disease using resistant cultivars is still a challenge. This work aimed to study the combining ability for CBB resistance in Phaseolus vulgaris genotypes. Six parents (two genotypes of CBB-resistant dry bean and four susceptible snap bean accessions were crossed in a complete diallel scheme without reciprocals to estimate the general and specific ability to Xap resistance. CBB resistance was evaluated by the inoculation with two Xap isolates, and its severity was evaluated based on the four following resistance components: area under the disease progress curve; scores in the leaves; latent period and diameter of pod lesion. Differences between the two isolates were observed considering all the disease components. Besides pathogen variability, significant GCA and SCA indicate that additive and non-additive effects are involved in Xap-resistance control for the evaluated genotypes, implying that CBC resistance is a trait with complex inheritance. For breeding purposes, the result demonstrates the need to apply breeding methods that are focused on advanced generations selection.

  3. Transfer of bacterial blight resistance from Oryza meyeriana to O.Sativa L.by asymmetric somatic hybridization

    Institute of Scientific and Technical Information of China (English)

    ZHU Yongsheng; CHEN Baotang; YU Shunwu; ZHANG Duanpin; ZHANG Xueqin; YAN Qiusheng

    2004-01-01

    Asymmetric somatic hybrid plants were produced between cultivated rice (Oryza sativa L.) and wild species [O. Meyeriana (Zoll. etMor, exSteud.)] with high resistance to rice bacterial blight. X-ray-irradiated protoplasts of the wild species were used as donor and chemically fused with iodoacetamide-inactivated protoplasts of rice cv. 02428to produce hybrids. Seventy-two plants were regenerated from 623 calli based on metabolic complementation. The morphological characters of the plants closely resembled that of the rice. Simple sequence repeats were employed to identify their hybridity. Cytological analysis of root-tips revealed that their chromosome number varied in the range of 27-38. The somatic hybrids were inoculated with strains of Xanthamonas oryzae pv. Oryzae at adult growth stage and demonstrated the resistance to bacterial blight introgression from the O. Meyeriana.

  4. Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L. and Oryza meyeriana L.

    Institute of Scientific and Technical Information of China (English)

    严成其; 钱凯先; 薛刚平; 吴忠长; 陈跃磊; 颜秋生; 张雪琴; 吴平

    2004-01-01

    Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O.sativa and O.meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance.

  5. Production of bacterial blight resistant lines from somatic hybridization between Oryza sativa L.and Oryza meyeriana L.

    Institute of Scientific and Technical Information of China (English)

    严成其; 钱凯先; 薛刚平; 吴忠长; 陈跃磊; 颜秋生; 张雪琴; 吴平

    2004-01-01

    Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs. Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with highest resistance have been used in the rice bfeeding program for the improvement of bacterial blight resistance.

  6. Field evaluation of leaf blight-resistant plant introductions of Brassica Juncea and Brassica Rapa and elucidation of inheritance of resistance

    Science.gov (United States)

    Brassica leafy greens (Brassica juncea and Brassica rapa) represent one of the most economically important vegetable crop groups in the southeastern United States. In the last 10 years, numerous occurrences of a leaf blight disease on these leafy vegetables have been reported in several states. One ...

  7. Potential impact of a hybrid leaf blight disease that infects both carrot and potato

    Science.gov (United States)

    Alternaria dauci and Alternaria solani are two forms of necrotrophic fungi. A. dauci targets carrot crops, while A. solani mainly targets potato. Both species of Alternaria have been able to produce blight on their respective target plants. Recently, an A. dauci hybrid has appeared that is able to i...

  8. Gamma radiation-induced mutant of NSIC RC144 with broad-spectrum resistance to bacterial blight

    International Nuclear Information System (INIS)

    Mutant lines derived from gamma radiation-treated commercial variety NSIC RC144 were produced and screened for novel resistance to bacterial blight, one of the most serious diseases of rice. Preliminary screening of a bulk M2 population through induced method using race 3 of the pathogen Xanthomonas oryzae pv. oryzae (Xoo) resulted in the selection of 89 resistant plants. Subsequent repeated bacterial blight screenings and generation advance for five seasons resulted in the selection of two highly resistant M7 sister lines whose origin can be traced to a single M2 plant. DNA fingerprinting using 63 genome-wide simple sequence repeat (SSR) markers revealed an identical pattern in these lines. Using the same set of markers, they also exhibited 98% similarity to wild type NSIC RC144 indicating that the resistance is due to mutation and not due to genetic admixture or seed impurity. Two seasons of bacterial blight screening using 14 local isolates representing ten races of Xoo revealed an identical reaction pattern in these lines. The reaction pattern was observed to be unique compared to known patterns in four IRBB isolines (IRBB 4, 5, 7 and 21) with strong resistant reaction to bacterial blight suggesting possible novel resistance. The susceptible reaction in F1 testcrosses using Xoo race 6 and the segregation patterns in two F2 populations that fit with the expected 3 susceptible: 1 resistant ratio (P = 0.4, ns) suggest a single-gene recessive mutation in these lines. These mutants are now being used as resistance donor in the breeding program while further molecular characterization to map and characterize the mutated gene is being pursued

  9. Pyramiding blast, bacterial blight and brown planthopper resistance genes in rice restorer lines

    Institute of Scientific and Technical Information of China (English)

    JI Zhi-juan; Yang Shu-dong; ZENG Yu-xiang; LIANG Yan; YANG Chang-deng; QIAN Qian

    2016-01-01

    Rice blast, bacterial blight (BB) and brown planthopper (BPH) are the three main pests of rice. This study investigated pyr-amiding genes resistant to blast, BB and BPH to develop restorer lines. Ten new lines with blast, BB and/or BPH resistance genes were developed using marker-assisted selection (MAS) technique and agronomic trait selection (ATS) method. Only HR13 with resistance genes to blast, BB and BPH was obtained. In addition to blast and BB resistance, four lines (HR39, HR41, HR42, HR43) demonstrated moderate resistance to BPH, but MAS for BPH resistance genes were not conducted in developing these four lines. These data suggested that there were unknown elite BPH resistance genes in the Zhongzu 14 donor parent. A more effective defense was demonstrated in the lines withPi1 andPi2 genes although the weather in 2012 was favorable to disease incidence. Blast resistance of the lines with a single resistance gene,Pita, was easily inlfuenced by the weather. Overal, the information obtained through pyramiding multiple resistance genes on developing the restorer lines is helpful for rice resistance breeding.

  10. Identification of molecular markers linked to rice bacterial blight resistance genes from Oryza meyeriana

    Directory of Open Access Journals (Sweden)

    Jing WANG,Chen CHENG,Yanru ZHOU,Yong YANG,Qiong MEI,Junmin LI,Ye CHENG,Chengqi YAN,Jianping CHEN

    2015-09-01

    Full Text Available Y73 is a progeny of asymmetric somatic hybridization between Oryza sativa cv. Dalixiang and the wild rice species Oryza meyeriana. Inoculation with a range of strains of Xanthomonas oryzae pv. oryzae showed that Y73 had inherited a high level of resistance to rice bacterial blight (BB from its wild parent. An F2 population of 7125 individuals was constructed from the cross between Y73 and a BB-susceptible cultivar IR24. After testing 615 SSR and STS markers covering the 12 rice chromosomes, 186 markers were selected that showed polymorphism between Y73 and IR24. Molecular markers linked to the BB resistance genes in Y73 were scanned using the F2 population and the polymorphic markers. The SSR marker RM128 on chromosome 1, the STS marker R03D159 on chromosome 3 and the STS marker R05D104 on chromosome 5 were found to be linked to the rice BB resistance genes in Y73.

  11. Metabolite profiles of rice cultivars containing bacterial blight-resistant genes are distinctive from susceptible rice

    Institute of Scientific and Technical Information of China (English)

    Jiao Wu; Haichuan Yu; Haofu Dai; Wenli Mei; Xin Huang; Shuifang Zhu; Ming Peng

    2012-01-01

    The metabolic changes of bacterial blight-resistant line C418/Xa23 generated by molecular marker-assisted selection (n =12),transgenic variety C418-Xa21 generated by using the Agrobacterium-mediated system (n =12),and progenitor cultivar C418 (n =12) were monitored using gas chromatography/mass spectrometry.The validation,discrimination,and establishment of correlative relationships between metabolite signals were performed by cluster analysis,principal component analysis,and partial least squares-discriminant analysis.Significant and unintended changes were observed in 154 components in C418/Xa23 and 48 components in C418-Xa21 compared with C418 (P < 0.05,Fold change > 2.0).The most significant decreases detected (P< 0.001) in both C418/Xa23 and C418-Xa21 were in three amino acids: glycine,tyrosine,and alanine,and four identified metabolites: malic acid,ferulic acid,succinic acid,and glycerol.Linoleic acid was increased specifically in C418/Xa23 which was derived from traditional breeding.This line,possessing a distinctive metabolite profile as a positive control,shows more differences vs.the parental than the transgenic line.Only succinic acid that falls outside the boundaries of natural variability between the two non-transgenic varieties C418 and C418/Xa23 should be further investigated with respect to safety or nutritional impact.

  12. Nucleotide diversity analysis of three major bacterial blight resistance genes in rice.

    Directory of Open Access Journals (Sweden)

    Waikhom Bimolata

    Full Text Available Nucleotide sequence polymorphisms among R gene alleles influence the process of co-evolutionary interaction between host and pathogen by shaping the response of host plants towards invading pathogens. Here, we present the DNA sequence polymorphisms and diversities present among natural alleles of three rice bacterial blight resistance genes, Xa21, Xa26 and xa5. The diversity was examined across different wild relatives and cultivars of Oryza species. Functional significance of selected alleles was evaluated through semi-quantitative reverse transcription polymerase chain reaction and real time PCR. The greatest nucleotide diversity and singleton variable sites (SVS were present in Xa26 (π = 0.01958; SVS = 182 followed by xa5 and Xa21 alleles. The highest frequency of single nucleotide polymorphisms were observed in Xa21 alleles and least in xa5. Transition bias was observed in all the genes and 'G' to 'A' transitions were more favored than other form of transitions. Neutrality tests failed to show the presence of selection at these loci, though negative Tajima's D values indicate the presence of a rare form of polymorphisms. At the interspecies level, O. nivara exhibited more diversity than O. sativa. We have also identified two nearly identical resistant alleles of xa5 and two sequentially identical alleles of Xa21. The alleles of xa5 showed basal levels of expression while Xa21 alleles were functionally not expressed.

  13. REVIEW ON BANDED LEAF AND SHEATH BLIGHT OF RICE CAUSED BY Rhizoctonia solani KUHN

    OpenAIRE

    P. Srinivas; Ved Ratan; Atm Prakash Patel; G. Bindu Madhavi

    2013-01-01

    Rice (Oryza sativa L.) is a graminaceous crop. It is one of the important staple foods for Asian countries. Sheath blight disease is an important fungal disease of rice. Currently, this disease is distributed in almost all the rice growing states. The disease is alarming due to its intensive cultivation of modern high yielding varieties with high doses of nitrogenous fertilizers. Crop with a high plant density and close canopy associated favors disease build up from panicle initiation onwards...

  14. Identification and Fine Mapping of rhm1 Locus for Resistance to Southern Corn Leaf Blight in Maize

    Institute of Scientific and Technical Information of China (English)

    Yuanzeng Zhao; Xiaomin Lu; Chaoxian Liu; Haiying Guan; Mei Zhang; Zhongfeng Li; Hongwei Cai; Jinsheng Lai

    2012-01-01

    rhm1 is a major recessive disease resistance locus for Southern corn leaf blight (SCLB).To further narrow down its genetic position,F2 population and BC1F1 population derived from the cross between resistant (H95rhm) and susceptible parents (H95) of maize (Zea mays) were constructed.Using newly developed markers,rhm1 was initially delimited within an interval of 2.5 Mb,and then finally mapped to a 8.56 kb interval between InDel marker IDP961-503 and simple sequence repeat (SSR) marker A194149-1.Three polymorphic markers IDP961-504,IDP B2-3 and A194149-2 were shown to be co-segregated with the rhm1 locus.Sequence analysis of the 8.56 kb DNA fragment revealed that it contained only one putative gene with a predicted amino acid sequence identical to lysine histidine transporter 1 (LHT1).Comparative sequence analysis indicated that the LHT1 in H95rhm harbors a 354 bp insertion in its third exon as compared with that of susceptible alleles in B73,H95 and Mo17.The 354 bp insertion resulted in a truncation of the predicted protein of candidate resistance allele (LHT1-H95rhm).Our results strongly suggest LHT1 as the candidate gene for rhm1 against SCLB.The tightly linked molecular markers developed in this study can be directly used for molecular breeding of resistance to Southern corn leaf blight in maize.

  15. BIOLOGICAL CONTROL OF BANDED LEAF AND SHEATH BLIGHT DISEASE (Rhizoctonia solani KUHN IN CORN WITH FORMULATED Bacillus subtilis BR23

    Directory of Open Access Journals (Sweden)

    Amran Muis

    2016-10-01

    Full Text Available Rhizoctonia solani Kuhn. causing banded leaf and sheath blight diseases is one of the important fungi of corn world wide. The fungus is commonly controlled by using fungicide because no resistant variety available. The objective of the study was to develop a seed treatment formulation of the selected Bacillus subtilis to control R. solani in corn. The study was conducted in the Department of Plant Pathology, College of Agriculture, University of the Philippines Los Bañòs, College, Laguna from May 2004 to August 2005, using sweet corn var. IPB Supersweet as test plant. Corn seeds were surface sterilized for 10 minutes in 1% sodium hypochlorite solution and 5% ethanol, washed thrice with sterile distilled water and air-dried. The seeds were coated with formulated B. subtilis BR23 and used for several experiments, such as evaluation for their germination and growth in the laboratory, effectively on R. solani in the baked and nonbaked field soil under greenhouse condition, and in the microplots artificially infested with R. solani. The treatment was compared with other standard seed treatment of synthetic fungicides such as captan (10 g per kg seeds and metalaxyl (10 g per kg seeds. The experiments were designed in a completely random design with three replications. Parameters observed were seed germination, plant height, disease scores, and plant yield. Laboratory formulated B. subtilis BR23 used as seed treatment had no detrimental effects on seed germination and seedling vigor. In microplots artificially infested with a selected highly virulent R. solani, seed treatment with the same formulation increased grain yield by 27% compared to that of the control captan seed treatment with 14.4%. The studies showed the potential of B. subtilis BR23 for commercialization as a seed treatment for the control of banded leaf and sheath blight disease (R. solani in corn.

  16. Feasible Management of Southern Corn Leaf Blight via Induction of Systemic Resistance by Bacillus cereus C1L in Combination with Reduced Use of Dithiocarbamate Fungicides

    Directory of Open Access Journals (Sweden)

    Yi-Ru Lai

    2016-10-01

    Full Text Available Dithiocarbamate fungicides such as maneb and mancozeb are widely used nonsystemic protectant fungicides to control various plant fungal diseases. Dithiocarbamate fungicides should be frequently applied to achieve optimal efficacy of disease control and avoid either decline in effectiveness or wash-off from leaf surface. Dithiocarbamates are of low resistance risk but have the potential to cause human neurological diseases. The objective of this study was to develop a strategy to effectively control plant disease with reduced use of dithiocarbamtes. Southern corn leaf blight was the model pathosystem for the investigation. When corn plants were drench-treated with Bacillus cereus C1L, a rhizobacterium able to induce systemic resistance in corn plants against southern leaf blight, frequency of spraying dithiocarbamate fungicides could be decreased. The treatment of B. cereus C1L was able to protect maize from southern leaf blight while residues of dithiocarbamates on leaf surface were too low to provide sufficient protection. On the other hand, frequent sprays of mancozeb slightly but significantly reduced growth of corn plants under natural conditions. In contrast, application of B. cereus C1L can significantly promote growth of corn plants whether sprayed with mancozeb or not. Our results provide the information that plant disease can be well controlled by rhizobacteria-mediated induced systemic resistance in combination with reduced but appropriate application of dithiocarbamate fungicides just before a heavy infection period. An appropriate use of rhizobacteria can enhance plant growth and help plants overcome negative effects caused by dithiocarbamates.

  17. Feasible Management of Southern Corn Leaf Blight via Induction of Systemic Resistance by Bacillus cereus C1L in Combination with Reduced Use of Dithiocarbamate Fungicides

    Science.gov (United States)

    Lai, Yi-Ru; Lin, Pei-Yu; Chen, Chao-Ying; Huang, Chien-Jui

    2016-01-01

    Dithiocarbamate fungicides such as maneb and mancozeb are widely used nonsystemic protectant fungicides to control various plant fungal diseases. Dithiocarbamate fungicides should be frequently applied to achieve optimal efficacy of disease control and avoid either decline in effectiveness or wash-off from leaf surface. Dithiocarbamates are of low resistance risk but have the potential to cause human neurological diseases. The objective of this study was to develop a strategy to effectively control plant disease with reduced use of dithiocarbamtes. Southern corn leaf blight was the model pathosystem for the investigation. When corn plants were drench-treated with Bacillus cereus C1L, a rhizobacterium able to induce systemic resistance in corn plants against southern leaf blight, frequency of spraying dithiocarbamate fungicides could be decreased. The treatment of B. cereus C1L was able to protect maize from southern leaf blight while residues of dithiocarbamates on leaf surface were too low to provide sufficient protection. On the other hand, frequent sprays of mancozeb slightly but significantly reduced growth of corn plants under natural conditions. In contrast, application of B. cereus C1L can significantly promote growth of corn plants whether sprayed with mancozeb or not. Our results provide the information that plant disease can be well controlled by rhizobacteria-mediated induced systemic resistance in combination with reduced but appropriate application of dithiocarbamate fungicides just before a heavy infection period. An appropriate use of rhizobacteria can enhance plant growth and help plants overcome negative effects caused by dithiocarbamates. PMID:27721698

  18. Limitations of Cassava Bacterial Blight: New Advances Limitaciones de la bacteriosis vascular de yuca: Nuevos avances

    Directory of Open Access Journals (Sweden)

    Verdier Valérie

    2006-12-01

    Full Text Available Cassava (Manihot esculenta, a starchy root crop, constitutes the source of alimentation for over 600 million people worldwide. Cassava Bacterial Blight (CBB is caused bythe bacterium Xanthomonas axonopodis pv. manihotis (Xam. This review will focus on the current knowledge on the molecular cassava-Xam interaction. We will present the different molecular techniques developed to assess the genetic diversity and dynamics of Xam populations. We will also present different methods developed for detecting the pathogen in vegetative planting materials and true seeds and their contribution to reduce the impact of the disease. We will review different studies conducted to gain a better understanding on the molecular mechanisms and the genes involved in the cassava bacterial resistance, including the recent advances obtained using functional
    genomics. The acquired knowledge in the last years for this pathosystem will help to establish better disease control strategies and generate, in a short term, resistant cassava varieties contributing to solve one of the main problems of poor cassava farmers and this effort will open a new horizon to the cassava crop in the world.La yuca (Manihot esculenta constituye la base de la alimentación de más de 600 millones de personas en el mundo. Una de las principales limitaciones de este cultivo es la bacteriosis vascular, ocasionada por la bacteria Xanthomonas axonopodis pv. manihotis (Xam. Este artículo revisa el conocimiento actual acerca de la interacción Xanthomonas-yuca. Se presentan estudios recientes llevados a cabo sobre la diversidad y dinámica de las poblaciones de Xam empleando diferentes estrategias moleculares. Se describen los diferentes métodos desarrollados para la detección y diagnóstico de la bacteria en plantas y semillas de yuca y su contribución para reducir el impacto de la enfermedad. Se presentan los estudios encaminados a comprender los mecanismos moleculares y los genes

  19. LIMITACIONES DE LA BACTERIOSIS VASCULAR DE YUCA: NUEVOS AVANCES Limitations of Cassava Bacterial Blight: New Advances

    Directory of Open Access Journals (Sweden)

    CAMILO LÓPEZ

    Full Text Available La yuca (Manihot esculenta constituye la base de la alimentación de más de 600 millones de personas en el mundo. Una de las principales limitaciones de este cultivo es la bacteriosis vascular, ocasionada por la bacteria Xanthomonas axonopodis pv. manihotis (Xam. Este artículo revisa el conocimiento actual acerca de la interacción Xanthomonasyuca. Se presentan estudios recientes llevados a cabo sobre la diversidad y dinámica de las poblaciones de Xam empleando diferentes estrategias moleculares. Se describen los diferentes métodos desarrollados para la detección y diagnóstico de la bacteria en plantas y semillas de yuca y su contribución para reducir el impacto de la enfermedad. Se presentan los estudios encaminados a comprender los mecanismos moleculares y los genes responsables en la resistencia de la yuca a la bacteriosis vascular incluyendo los últimos avances obtenidos gracias a la aplicación de estrategias de genómica funcional. El conocimiento adquirido en los últimos años en este patosistema permitirá desarrollar mejores estrategias para el manejo de la enfermedad así como desarrollar a corto plazo variedades de yuca resistentes a la bacteriosis lo que contribuiría a resolver uno de los principales problemas de los productores pobres de yuca y le abriría un horizonte promisorio al cultivo de la yuca en el mundo.Cassava (Manihot esculenta, a starchy root crop, constitutes the source of alimentation for over 600 million people worldwide. Cassava Bacterial Blight (CBB is caused the bacterium Xanthomonas axonopodis pv. manihotis (Xam. This review will focus on the current knowledge on the molecular cassava-Xam interaction. We will present the different molecular techniques developed to assess the genetic diversity and dynamics of Xam populations. We will also present different methods developed for detecting the pathogen in vegetative planting materials and true seeds and their contribution to reduce the impact of the

  20. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-04-19

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively.

  1. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  2. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the −Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from −Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the −Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the −Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in −Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  3. Effect of Trichoderma harzianum biomass and Bradyrhizobium sp. strain NC 92 to control leaf blight disease of bambara groundnut (Vigna subterranea) caused by Rhizoctonia solani in the field

    OpenAIRE

    Mana Kanjanamaneesathian; Paranee Sawangsri; Ashara Pengnoo; Jira Suwanprasert

    2007-01-01

    Four hundred and sixty two strains of Trichoderma spp. were isolated from 23 soil samples in which groundnut (Arachis hypogaea L.) and bambara groundnut (Vigna subterranea L.) had been planted in Songkhla, Phattalung, Nakhon Si Thammarat, Narathiwat and Yala provinces. These fungi were tested against Rhizoctonia solani, a causal agent of leaf blight of bambara groundnut, using dual culture technique on PDA medium. Among 462 isolates tested, 226 isolates had an ability to overgrow R. solani co...

  4. Identification of Pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and Detection of Quantitative Trait Loci and Markers for Resistance to Bacterial Blight of Cassava.

    Science.gov (United States)

    Wydra, K; Zinsou, V; Jorge, V; Verdier, V

    2004-10-01

    ABSTRACT Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype-environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F(1) cassava genotypes deriving from the male parent 'CM2177-2' and the female parent 'TMS30572' were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population were resistant to stem inoculation by four strains of X. axonopodis pv. manihotis from different locations in Africa, and 19 groups with differential reactions to the four strains were identified, suggesting that the strains represent different pathotypes. Four genotypes were resistant to leaf inoculation, and three were resistant to both stem and leaf inoculations. Genotypes with susceptible, moderately resistant, and resistant reactions after leaf and stem inoculation partly differed in their reactions on leaves and stems. Based on the genetic map of cassava, single-markeranalysis of disease severity after stem-puncture inoculation was performed. Eleven markers were identified, explaining between 16 and 33.3% of phenotypic variance of area under disease progress curve. Five markers on three and one linkage groups from the female- and male-derived framework of family CM8820, respectively, seem to be weakly associated with resistance to four strains of X. axonopodis pv. manihotis. Based on the segregation of alleles from the female of family CM8873, one marker was significantly associated with resistance to two X. axonopodis pv. manihotis strains, GSPB2506 and GSPB2511, whereas five markers were not linked to any linkage group. The quantitative trait loci (QTL) mapping results also suggest that the four African strains belong to four different pathotypes. The identified pathotypes should be useful for screening for resistance, and the QTL and markers will support

  5. Association mapping of common bacterial blight resistance QTL in Ontario bean breeding populations

    Directory of Open Access Journals (Sweden)

    Navabi Alireza

    2011-03-01

    Full Text Available Abstract Background Common bacterial blight (CBB, incited by Xanthomonas axonopodis pv. phaseoli (Xap, is a major yield-limiting factor of common bean (Phaseolus vulgaris L. production around the world. Host resistance is practically the most effective and environmentally-sound approach to control CBB. Unlike conventional QTL discovery strategies, in which bi-parental populations (F2, RIL, or DH need to be developed, association mapping-based strategies can use plant breeding populations to synchronize QTL discovery and cultivar development. Results A population of 469 dry bean lines of different market classes representing plant materials routinely developed in a bean breeding program were used. Of them, 395 lines were evaluated for CBB resistance at 14 and 21 DAI (Days After Inoculation in the summer of 2009 in an artificially inoculated CBB nursery in south-western Ontario. All lines were genotyped using 132 SNPs (Single Nucleotide Polymorphisms evenly distributed across the genome. Of the 132 SNPs, 26 SNPs had more than 20% missing data, 12 SNPs were monomorphic, and 17 SNPs had a MAF (Minor Allelic Frequency of less than 0.20, therefore only 75 SNPs were used for association study, based on one SNP per locus. The best possible population structure was to assign 36% and 64% of the lines into Andean and Mesoamerican subgroups, respectively. Kinship analysis also revealed complex familial relationships among all lines, which corresponds with the known pedigree history. MLM (Mixed Linear Model analysis, including population structure and kinship, was used to discover marker-trait associations. Eighteen and 22 markers were significantly associated with CBB rating at 14 and 21 DAI, respectively. Fourteen markers were significant for both dates and the markers UBC420, SU91, g321, g471, and g796 were highly significant (p ≤ 0.001. Furthermore, 12 significant SNP markers were co-localized with or close to the CBB-QTLs identified previously in bi

  6. Vegetative Compatibility Groups in Cercospora kikuchii, the Causal Agent of Cercospora Leaf Blight and Purple Seed Stain in Soybean.

    Science.gov (United States)

    Cai, G; Schneider, R W

    2005-03-01

    ABSTRACT Nitrogen nonutilizing (Nit) mutants were used to assess vegetative compatibility of 58 isolates of Cercospora kikuchii, 55 of which were isolated from soybean plants in Louisiana. Two isolates were vegetatively self-incompatible. Of 56 self-compatible isolates, 16 were assigned to six multimember vegetative compatibility groups (VCGs), 01 to 06, with 2 or 3 isolates in each VCG. The other 40 isolates each belonged to a distinct VCG. All six multimember VCGs contained isolates from different soy bean cultivars, and three included isolates from different locations. Only one of six multimember VCGs included isolates both from soybean leaves and seed, while the other five included isolates from only leaves or seed. The likelihood of tissue specificity or preference was discussed. All isolates and tested Nit mutants produced cercosporin on potato dextrose agar under light. Significantly different amounts of cercosporin were produced among wild-type isolates, and two Nit mutants produced significantly more cercosporin than their wild-type counterparts. All isolates produced typical Cercospora leaf blight symptoms on soybean plants in greenhouse pathogenicity tests.

  7. Cloning of a peroxidase gene from cassava with potential as a molecular marker for resistance to bacterial blight

    Directory of Open Access Journals (Sweden)

    Pereira Luiz Filipe

    2003-01-01

    Full Text Available Cassava bacterial blight (CBB, caused by Xanthomonas axonopodis pv. manihotis, is considered one of the most important bacterial diseases of cassava (Manihot esculenta Crantz. In order to characterize the cassava genes involved in resistance to this disease, a genomic clone of a cationic peroxidase gene, MEPX1, was isolated by PCR from cassava cultivar MCOL 22. The DNA sequence of MEPX1 showed high homology with other plant peroxidase genes and contained a large intron typical of peroxidase genes. The predicted translation product showed a heme-ligand motif, also a characteristic of peroxidases, as well as phosphorylation, myristoylation and glycosylation sites. The amino acid sequence had 75 % homology with two Arabidopsis thaliana peroxidases. A Southern blot of 17 cassava cultivars, probed with MEPX1, showed multiple hybridization bands. Polymorphisms between cultivars generally reflected geographic origin, but there was also an association with resistance to CBB, indicating that MEPX1 could be a potentially useful marker for this trait.

  8. REVIEW ON BANDED LEAF AND SHEATH BLIGHT OF RICE CAUSED BY Rhizoctonia solani KUHN

    Directory of Open Access Journals (Sweden)

    P. Srinivas

    2013-12-01

    Full Text Available Rice (Oryza sativa L. is a graminaceous crop. It is one of the important staple foods for Asian countries. Sheath blight disease is an important fungal disease of rice. Currently, this disease is distributed in almost all the rice growing states. The disease is alarming due to its intensive cultivation of modern high yielding varieties with high doses of nitrogenous fertilizers. Crop with a high plant density and close canopy associated favors disease build up from panicle initiation onwards. Poor weed management practices and increase in frequency of irrigation have aggravated, incidence of the disease due to modified micro climatic conditions. The disease was first recorded from Japan (Miyake, 1910. In India, the disease was first reported from Gurudaspur, Punjab (Paracer and Chahal, 1963 and later it was reported from Uttar Pradesh (Kohli, 1966. The management of this disease is possible only after the detailed study of different aspect of this disease and the pathogen. Management of the disease below its economic threshold is important for increasing the production, productivity and quality of the produce. Recognizing the importance of the problem, need for the effective and socio economically feasible management of the pathogen, the present review presented by keeping the above stated factors of the disease into consideration.

  9. Quantitative Trait Loci in Sweet Corn Associated with Partial Resistance to Stewart's Wilt, Northern Corn Leaf Blight, and Common Rust.

    Science.gov (United States)

    Brown, A F; Juvik, J A; Pataky, J K

    2001-03-01

    ABSTRACT Partial resistance to Stewart's wilt (Erwina stewartii, syn. Pantoea stewartii), northern corn leaf blight (NCLB) (Exserohilum turcicum), and common rust (Puccinia sorghi) was observed in an F(2:3) population developed from a cross between the inbred sweet corn lines IL731a and W6786. The objective of this study was to identify quantitative trait loci (QTL) associated with partial resistance using restriction fragment length polymorphic markers. Phenotypic data were collected for 2 years for Stewart's wilt, NCLB, and common rust but, due to significant family-environment interaction, analysis was conducted individually on data from each year. In 2 years of evaluation for the three diseases, a total of 33 regions in the maize genome were associated with partial resistance describing from 5.9 to 18% of the total phenotypic variability. Of six regions common in both years, three were associated with partial resistance to Stewart's wilt (chromosomes 4:07, 5:03, and 6:04), one was associated with NCLB (chromosome 9:05), and two were associated with common rust (chromosomes 2:04 and 3:04). The rust QTL on 3S mapped to within 20 cM of the rp3 locus and explained 17.7% of the phenotypic variability. Some of the QTL associated with partial resistance to the three diseases have been reported previously, and some are described here for the first time. Results suggest it may be possible to consolidate QTL from various elite backgrounds in a manner analogous to the pyramiding of major resistance genes. We also report here on two QTL associated with anthocyanin production on chromosomes 10:6 and 5:03 in the general location of the a2 gene. PMID:18943349

  10. 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

  11. Breeding Rice Restorer Lines with High Resistance to Bacterial Blight by Using Molecular Marker-Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    DENG Qi-ming; WANG Shi-quan; ZHENG Ai-ping; ZHANG Hong-yu; LI Ping

    2006-01-01

    Two bacterial blight (BB) resistance genes, Xa21 and Xa4, from IRBB24 were introduced into hybrid rice restorer line Mianhui 725, which is highly susceptible to BB, by using hybridization and molecular marker-assisted selection technology. Four homologous restorer lines were obtained through testing the R target genes with molecular markers and analyzing parental genetic background. Inoculation of the four lines and their hybrids with the specific strains of Xanthomonas oryzae pv. oryzae, P1, P6 and seven representative strains of Chinese pathotype, C Ⅰ -CⅦ, showed that all of the four lines and their hybrids were highly resistant and presented broad resistance-spectrum to BB. The hybrids of G46A / R207-2 displayed good agronomic characters and high yield potential, and R207-2 was named Shuhui 207.

  12. Characterization of novel bacteriophages for biocontrol of bacterial blight in leek caused by Pseudomonas syringae pv. porri

    Directory of Open Access Journals (Sweden)

    Sofie eRombouts

    2016-03-01

    Full Text Available Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum, is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4 and vB_PsyM_KIL5, and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b. Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the ‘KIL-like viruses’, related to the Felixounalikevirus genus, together with phage phiPsa374 from Pseudomonas syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3 and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  13. Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri.

    Science.gov (United States)

    Rombouts, Sofie; Volckaert, Anneleen; Venneman, Sofie; Declercq, Bart; Vandenheuvel, Dieter; Allonsius, Camille N; Van Malderghem, Cinzia; Jang, Ho B; Briers, Yves; Noben, Jean P; Klumpp, Jochen; Van Vaerenbergh, Johan; Maes, Martine; Lavigne, Rob

    2016-01-01

    Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the "KIL-like viruses," related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  14. First record of Glomerella cingulata causing leaf blight on Talauma ovata (Magnoliaceae) Primeiro relato de Glomerella cingulata causando queima foliar em Talauma ovata (Magnoliaceae)

    OpenAIRE

    Bruno Sérgio Vieira; Olinto Liparini Pereira; Márcio Luiz Batista; Robert Weingart Barreto

    2005-01-01

    Glomerella cingulata was found causing severe leaf blight on Talauma ovata, a common tree species in the Atlantic tropical rain forest floodplains of Southern Brazil. The disease and pathogen are described and illustrated and patogenicity is also demonstrated. This is the first report of this disease.Glomerella cingulata foi encontrado causando severa queima-foliar em Talauma ovata, uma espécie arbórea comum em florestas úmidas tropicais do Sudeste do Brasil. A doença e o patógeno foram descr...

  15. In-vitro evaluation of fungicides, bioagents and aqueous leaf extracts against Alternaria leaf blight of cotton

    Directory of Open Access Journals (Sweden)

    U. Dey

    2012-07-01

    Full Text Available All the six fungicides viz.,Mancozeb (75% WP; Carbendazim (50WP, Copper oxychloride (50WP, Captan (50 WP, Thiram (75 % WP, Chlorothalonil (75 WP evaluated in vitro (@500, 1000 and 1500 ppm were found effective against A. macrospora and caused significant inhibition of test pathogen over untreated control. However, Thiram was found most effective and recorded significantly highest mean mycelial inhibition (90.42%. This was followed by the fungicides, Captan (82.04%, Mancozeb (79.88%, Carbendazim(77.5%, Chlorothalonil (74.52% and copper oxychloride (71.75%. All the five fungal and one bacterial bioagents/ antagonists evaluated in vitro against A. macrospora were found antifungal/ antagonistic against the test pathogen. However, T. viride was found most effective and recorded least linear mycelial growth (32.72 mm with corresponding significantly highest mycelial inhibition (63.64% of the test pathogen. The second and third best bioagents found were T. koningii and P. fluorescens, which recorded linear mycelial growth, respectively of 33.90 mm and 33.95 mm with corresponding mycelial inhibition, respectively of 62.33 and 62.27 per cent. All the six botanicals/plant extracts evaluated in vitro (@5, 10 and 15 % each were found fungistatic/ fungicidal against. A.macrospora. However, significantly least mean radial mycelial growth (56.18mm and significantly highest mean mycelial inhibition (37.47% was recorded with Garlic. The second and third best botanicals found were onion and Tulsi which recorded second and third least mean radial mycelial growth, respectively of 58.52 mm and 62.51 mm with corresponding mean mycelial inhibition of 34.97 and 32.86 per cent, respectively.

  16. Leaf blight of catharanthus roseus (l). g. don caused by macrophomina phaseolina (tassi) goid and its in vitro control through bio-pesticides

    International Nuclear Information System (INIS)

    Catharanthus roseus (L.).G. Don, a highly valued medicinal plant suffers from a serious disease. A survey on the symptom and severity of the leaf blight of C. roseus was performed in the nurseries of the Institute of Forestry and Environmental Sciences (IFESCU), Bangladesh Council of Industrial Research (BCSIR) and Bangladesh Forest Research Institute (BFRI), Bangladesh. An observation was also made in the avenues and garden of King Saud University (KSU), Kingdom of Saudi Arabia. No disease was recorded in KSU, but severe infections were found in all the locations surveyed in Bangladesh. The highest infection percentage and the highest disease index were found in BCSIR nursery followed by BFRI and the lowest was recorded in IFESCU nursery. Macrophomina phaseolina (Tassi) Goid was isolated and it was proved to be pathogenic. This is the first report of leaf blight of C. roseus caused by M. phaseolina. Azadirachta indica, Ocimum sanctum Vitex negundo, Mucuna pruriens, Calotropis procera, Terminalia arjuna, Allium sativum, Zingiber officinalis and Allium cepa were used as biopesticides. Out of the nine plant species screened, T. arjuna showed the highest (58.37%) inhibition percentage which was followed by A. indica (55.72%) and the lowest (27.4%) inhibition percentage were obtained with V. negundo whereas the rest of the plant extracts showed more or less same inhibitory effect. (author)

  17. 国内木薯病害普查及细菌性萎蔫病安全性评估%General Survey on Cassava Diseases and Safety Assessment of Cassava Bacterial Blight

    Institute of Scientific and Technical Information of China (English)

    李超萍; 时涛; 刘先宝; 蔡吉苗; 裴月令; 黄贵修

    2011-01-01

    2007~2010年,对广西、海南、云南等木薯主产区进行病害普查.结果发现,至今危害国内木薯的主要病害有7种,包括真菌病害6种[褐斑病(Cercosporidium henningsii)、炭疽病(colletotrichum gloeosPorioides)、离孺孢叶斑病(Bipolaris setariae)、棒孢霉叶斑病(Corynespora cassiicola)、白点病(phaeoramularia manihotis)和萎蔫叶斑病(Cercospora vicosae)],细菌病害1种[细菌性萎蔫病(Xanthomonas axonopodis pv manihotis)],其中离孺孢叶斑病和棒孢霉叶斑病为新发病害;7种病害中褐斑病和细菌性萎蔫病发生面积最大,危害最为严重.风险评估结果表明,细菌性萎蔫病菌为高度危险性有害生物.%During 2007 to 2010, cassava(Manihot esculenta Crantz)diseases survey was conducted in Guangxi, Hainan and Yunnan, the main cassava planting areas of China. The results showed that only seven diseases, six fungal diseases and one bacterial disease, were found. The cassava brown leaf spot caused by Cercosporidium henningsii and the bacterial blight caused by Xanthomonas axonopodis pv Manihotis prevailed in most cassava planting areas and caused serious damage. The safety assessment indicated that the cassava bacterial blight was a high risk disease. At present, cassava diseases are becoming one of the most important limiting factors for the development of cassava industry and would have a very serious,potential economic risk on correlative industry and the ecology of the tropic area.

  18. Field evaluation of different antibacterial antibiotic and plant extracts against bacterial blight of soybean caused by pseudomonas syringae pv. glycinea

    Directory of Open Access Journals (Sweden)

    G.P. Jagtap

    2012-08-01

    Full Text Available A field experiment was carried out to study effect of different antibacterial antibiotics and plant extracts against bacterial blight of soybean caused by Pseudomonas syringae pv. glycinea. The highest mean per cent disease incidence 35.51 per cent was observed in poushamycin treatment. The lowest mean per cent disease incidence 12.74 per cent was found in treatment streptocycline 100 ppm + Copper oxychloride (@0.25% and recorded highest seed yield (2605 kg/ha and test weight (14.33 g is superior over rest of treatments which was at par with streptocycline 100 ppm (14.28%, copper oxychloride (19.40 and Bactinashak 500 ppm (25.12%. The highest mean per cent disease incidence 28.16 per cent was observed in Tulsi and lowest mean per cent disease incidence 15.03 per cent was found in treatment Neem. Sprays of Neem is superior over rest of treatment minimum disease incidence was observed in this treatments (11.00 % and which was at par with Ginger Garlic, Onion and Tulsi.

  19. Fine mapping of the rice bacterial blight resistance gene Xa-4 and its co-segregation marker

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An F2 population developed from the Xa-4 near isogenic lines,IR24 and IRBB4,was used for fine mapping of the rice bacterial blight resistance gene,Xa-4.Some restriction fragment length polymorphism (RFLP) markers on the high-density map constructed by Harushima et al.and the amplified DNA fragments homologous to the conserved domains of plant disease resistance (R) genes were used to construct the genetic linkage map around the gene Xa-4 by scoring susceptible individuals in the population.Xa-4 was mapped between the RFLP marker G181 and the polymerase chain reaction (PCR) marker M55.The R gene homologous fragment marker RS13 was found co-segregating with Xa-4 by analyzing all the plants in the population.This result opened an approach to map-based cloning of this gene,and marker RS13 can be applied to molecular marker-assisted selection of Xa-4 in rice breeding programs.

  20. 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.

  1. Improvement of Basmati rice varieties for resistance to blast and bacterial blight diseases using marker assisted backcross breeding.

    Science.gov (United States)

    Ellur, Ranjith K; Khanna, Apurva; Yadav, Ashutosh; Pathania, Sandeep; Rajashekara, H; Singh, Vikas K; Gopala Krishnan, S; Bhowmick, Prolay K; Nagarajan, M; Vinod, K K; Prakash, G; Mondal, Kalyan K; Singh, Nagendra K; Vinod Prabhu, K; Singh, Ashok K

    2016-01-01

    Marker assisted backcross breeding was employed to incorporate the blast resistance genes, Pi2 and Pi54 and bacterial blight (BB) resistance genes xa13 and Xa21 into the genetic background of Pusa Basmati 1121 (PB1121) and Pusa Basmati 6. Foreground selection for target gene(s) was followed by arduous phenotypic and background selection which fast-tracked the recovery of recurrent parent genome (RPG) to an extent of 95.8% in one of the near-isogenic lines (NILs) namely, Pusa 1728-23-33-31-56, which also showed high degree of resemblance to recurrent parent, PB6 in phenotype. The phenotypic selection prior to background selection provided an additional opportunity for identifying the novel recombinants viz., Pusa 1884-9-12-14 and Pusa 1884-3-9-175, superior to parental lines in terms of early maturity, higher yield and improved quality parameters. There was no significant difference between the RPG recovery estimated based on SSR or SNP markers, however, the panel of SNPs markers was considered as the better choice for background selection as it provided better genome coverage and included SNPs in the genic regions. Multi-location evaluation of NILs depicted their stable and high mean performance in comparison to the respective recurrent parents. The Pi2+Pi54 carrying NILs were effective in combating a pan-India panel of Magnaporthe oryzae isolates with high level of field resistance in northern, eastern and southern parts of India. Alongside, the PB1121-NILs and PB6-NILs carrying BB resistance genes xa13+Xa21 were resistant against Xanthomonas oryzae pv. oryzae races of north-western, southern and eastern parts of the country. Three of NILs developed in this study, have been promoted to final stage of testing during the ​Kharif 2015 in the Indian National Basmati Trial. PMID:26566849

  2. Breeding of R8012, a Rice Restorer Line Resistant to Blast and Bacterial Blight Through Marker-Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    ZHAN Xiao-deng; ZHOU Hai-peng; CHAI Rong-yao; ZHUANG Jie-yun; CHENG Shi-hua; CAO Li-yong

    2012-01-01

    Genetic improvement Is one of the most effective strategies to prevent rlce from blast and bacterial blight (BB)diseases,the two most prevalent diseases jeopardizing rice production.Rice hybrids with dural resistance to blast and BB are needed for sustainable production of food.An incomplete diallels design resulted in 25 crosses between five blast and five BB resistant germplasrn accesslons.Only one pair of parents,DH146 × TM487,showed polymorphism for all the markers to Identify one blast resistance gene P125 and three BB resistance genes,Xa21,xa13 and xa5,thus it was used in the marker-assisted selection (MAS).F2 individuals of DH148 × TM487 were genotyped using flanking markers of RM3330and sequence tagged site (STS) marker SAT for P125.The resistant F2 plants with P125 were used for pyramiding BB resistance genes Xa21,xa13 and xa5 identified by the markers pTA248,RM264 and RM153,respectively In subsequent generations.Finally,after selection for agronomic traits and restoration ability among 12 pyramided lines,we acquired an elite restorer line,R8012 including all four target genes (P125+Xa21+xa13+xa5).Hybrid Zhong 9A/R8012 derived from the selected line showed stronger resistance to blast and BB,and higher grain yield than the commercial checks uniformally in experimental plots,2007 state-wide yield trial and 2008 nation-wide yield trial.This study provides a paradigmatic example to show that MAS is a practically feasible tool in effectively pyramiding multiple resistance genes.The resultant restoring line and its hybrid would play an important role in securing rice production in China.

  3. Induction of bacterial blight resistance in elite Indian rice (Oryza sativa L.) cultivars using gamma irradiation and ethyl methane sulfonate

    International Nuclear Information System (INIS)

    Rice is one of the most important crops in the world, feeding more than 50% of the human population. During the last 30 years, mutation breeding has played a significant role in rice breeding programmes. Rice mutants with higher yield, greater tolerance to diseases and pests and other agronomic qualities have been released for commercial cultivation in many countries. By the year 1991, as many as 278 rice cultivars had been released world-wide out of which 24 were from India. Bacterial blight (BB) caused by Xanthomonas oryzae pv oryzae is the second most important disease in southeast Asia, causing an average of 21 kg/ha yield loss. In the Basmati field yield loss can reach up to 100%. Moreover, there is no resistant source of Basmati rice known for its quality and aroma. Induction of bacterial blight resistance in basmati rice will not only help in developing high yielding Basmati cultivars without compromising the quality but will also be a good source of resistance for other Basmati rice varieties. Therefore, seeds of two Indian rice varieties viz. PR106 and Pusa Basmati 1 were treated with EMS (0.25% and 0.5%) at pH 7.0 at 25 ± 1 deg C for 12 h and gamma rays (100 and 200 Gy). A 3500-curie 60Co gamma cell with a dose rate of 3200 radians per minute was used for gamma irradiation of the paddy seeds containing 13% moisture. After mutagenic treatment seeds were germinated along with corresponding controls in petri dishes lined with wet filter paper. The seeds from the M1 generation were grown in the plant-to- progeny method for the M2 generation at Kapurthala, Punjab Agricultural University. Each progeny had 22-25 plants. The plant-to-plant distance was 20 cm and row-to-row distance was 30 cm. For every 20 lines, one line of check (parent variety) was grown. Screening against BB was made in the M2 generation by inoculating the plants at maximum tillering stage, following Kauffman et al. (1973). Observations for disease severity were recorded after 14 days of

  4. Survey for incidence and severity of bacterial blight of cotton caused by Xanthomonas axonopodis pv. malvacearum in different districts of Marathwada region

    Directory of Open Access Journals (Sweden)

    D. Utpal

    2012-07-01

    Full Text Available An extensive roving survey was conducted in different districts of Marathwada region of Maharashtra State to isolate the pathogen associated with the bacterial blight disease of cotton. In all 76 cotton fields were surveyed and average disease incidence (PI to the tune of 51.12 per cent has been observed. Highest disease incidence noticed in Parbhani district (67% followed by Hingoli (63%, Nanded (58% and Latur (54%. The lowest disease incidence noticed in Jalna district (36%. Highest disease severity noticed in Parbhani district followed by Hingoli, Latur, Nanded and Aurangabad.

  5. Identification of pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and detection of quantitative trait loci and markers for resistance to bacterial blight of Cassava

    OpenAIRE

    Wydra, Kerstin; Zinsou, Valerien; Jorge, Véronique; Verdier, Valérie

    2004-01-01

    Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype–environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F1 cassava genotypes deriving from the male parent ‘CM2177-2’ and the female parent ‘TMS30572’ were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population ...

  6. Controle da mancha acinzentada da cebola e seu impacto sobre a qualidade de mudas Control of onion leaf blight (Botrytis squamosa and their impact on the seedling quality

    Directory of Open Access Journals (Sweden)

    João Américo Wordell Filho

    2006-12-01

    Full Text Available O presente trabalho estudou o efeito da adubação química e orgânica, fungicidas, fertilizantes foliares e extratos vegetais sobre a severidade da mancha acinzentada causada por Botrytis squamosa e a qualidade de mudas de cebola. Para tanto, realizou-se um experimento na Epagri/Estação Experimental de Ituporanga, SC, no período de maio a julho de 2005. Em um delineamento experimental de blocos casualizados com quatro repetições, em esquema de parcela sub-dividida, testou-se os seguintes tratamentos (Fator A: a testemunha; b fungicida ciprodinil (75 g i.a./100 L; c fosfito de potássio (00-30-20, 250 mL/100 L; d fertilizante foliar (03-00-16, 400 mL/100 L; e calda bordalesa (0,3%; f calda bordalesa/fosfito de potássio; g extrato da alga Ulva fasciata (0,2%, peso seco: volume; h extrato de cavalinha Equisetum arwense (0,26%; i extrato de Urtiga dióica (0,47%. Os canteiros foram conduzidos com adubação química ou orgânica (Fator B. A área foliar necrosada foi avaliada semanalmente e usada para calcular a área abaixo da curva de progresso da doença (AACPD. O tipo de fertilização não afetou o desenvolvimento da mancha acinzentada, porém a adubação química aumentou o comprimento e o diâmetro do pseudocaule das mudas. Os tratamentos ciprodinil, fosfito de potássio, fertilizante foliar (03-00-16, calda bordalesa e fosfito combinado com calda bordalesa, reduziram significativamente a doença, enquanto que os extratos não foram eficazes.This work studied the effect of mineral and organic fertilization, fungicides, foliar fertilizers and plant extracts on the severity of onion leaf blight caused by Botrytis squamosa and onseedling quality. Field experiment was carried out at Epagri's experimental station in Ituporanga-SC from May to July 2005. In a split-plot design with four replicates the following treatments (factor A were tested: a control; b fungicide ciprodinil (75 g a.i./100 L; c potassium fosfite (00-30-20, 250 mL./100 L

  7. Influence of 3 Trichoderma Strains on the Pathogenic Bacterium of Leaf Blight from Poplar Tree%3株木霉对杨树叶枯病病原菌的影响

    Institute of Scientific and Technical Information of China (English)

    周秀华; 崔磊

    2011-01-01

    The confironting culture was performed on 3 Trichoderma strains and pathogenic bacterium of leaf blight from poplar tree using PDA synthetic medium and the inhibition effect of Trichoderma on pathogenic bacterium was investigated. The results showed that all of the 3 Trichoderma strains had antagonistic action on the pathogenic bacterium of leaf blight from poplar tree and the inhibition effect of Trichoderma citrinoviride 2 was best.%采用PDA综合培养基对3株木霉和杨树叶枯病病原菌进行对峙培养,考察木霉对病原菌的抑制效果.结果表明,3株木霉对杨树叶枯病痛原菌均具有拮抗作用,其中桔绿木霉2的抑菌效果最佳.

  8. Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance.

    Science.gov (United States)

    Abhilash Kumar, V; Balachiranjeevi, C H; Bhaskar Naik, S; Rambabu, R; Rekha, G; Harika, G; Hajira, S K; Pranathi, K; Anila, M; Kousik, M; Vijay Kumar, S; Yugander, A; Aruna, J; Dilip Kumar, T; Vijaya Sudhakara Rao, K; Hari Prasad, A S; Madhav, M S; Laha, G S; Balachandran, S M; Prasad, M S; Viraktamath, B C; Ravindra Babu, V; Sundaram, R M

    2016-01-01

    RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the

  9. Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance.

    Science.gov (United States)

    Abhilash Kumar, V; Balachiranjeevi, C H; Bhaskar Naik, S; Rambabu, R; Rekha, G; Harika, G; Hajira, S K; Pranathi, K; Anila, M; Kousik, M; Vijay Kumar, S; Yugander, A; Aruna, J; Dilip Kumar, T; Vijaya Sudhakara Rao, K; Hari Prasad, A S; Madhav, M S; Laha, G S; Balachandran, S M; Prasad, M S; Viraktamath, B C; Ravindra Babu, V; Sundaram, R M

    2016-01-01

    RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the

  10. Identification and gene prediction of a 24 kb region containing xa5, a recessive bacterial blight resistance gene in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yiming; JIANG Guanghuai; CHEN Xuewei; XIA Zhihui; LI Xiaobing; ZHU Lihuang; ZHAI Wenxue

    2003-01-01

    Rice xa5 gene provides recessive, race-specific resistance to bacterial blight disease caused by the pathogen Xanthomonas oryzae pv. oryzae and has great value for research and breeding. In an effort to clone xa5, an F2 population of 4892 individuals was developed from the xa5 near isogenic lines, IR24 and IRBB5. A fine mapping procedure was conducted and tightly linked RFLP markers were used to screen a BAC library of IRBB56, a resistant rice line containing the xa5 gene. A 213 kb contig covering the xa5 locus was constructed. According to the sequences from the International Rice Genome Sequening Project (IRGSP), the Chinese Superhybrid Rice Genome Project (SRGP) and some sub-clones of the contig, twelve SSLP and CAPS markers were developed for fine mapping. The xa5 gene was mapped to a 0.3 cM interval between markers K5 and T4, which spanned an interval of approximately 24 kb, co-segregating with marker T2. Sequence analysis of the 24 kb region revealed that an ABC transporter and a basal transcription factor (TFIIa) were potential candidates for the xa5 resistance gene product. The molecular mechanism by which the xa5 gene provides recessive, race-specific resistance to bacterial blight will be elucidated by the functional tests of the 24 kb DNA and the candidate genes.

  11. 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.

  12. 枯草芽孢杆菌B47菌株抗菌物质的分离纯化及其对玉米小斑病的防治作用%Purification of Antimicrobial Substance Produced by Bacillus subtilis B47 and Its Effect on Southern Corn Leaf Blight

    Institute of Scientific and Technical Information of China (English)

    叶云峰; 黎起秦; 袁高庆; 付岗; 缪剑华; 林纬

    2011-01-01

    枯草芽孢杆菌Bacillus subtilis菌株B47为番茄内生细菌,能产生对多种植物病原菌有抑制作用的抗菌物质。通过盐酸沉淀、甲醇抽提、硅胶柱层析、凝胶过滤层析和反相高效液相色谱(RP-HPLC)法提取和纯化到该抗菌物质。理化性质测定结果表明,该物质热稳定性和抗紫外线稳定性好;在碱条件下稳定;对蛋白酶不敏感;能溶于甲醇;双缩脲反应呈阳性,茚三酮反应呈阴性,但经酸水解后茚三酮反应呈阳性,推测该物质可能为环肽类物质。该物质对测试的14种病原真菌有拮抗作用,其中,对玉米大小斑病菌和各种香蕉叶斑病菌的拮抗作用%Bacillus subtilis B47 is an endophytic bacterium of tomato,and produces a substance to inhibit some plant pathogens.The antimicrobial substance was extracted and purified by hydrochloric acid precipitation,methanol extraction,silica gel column chromatography,gel filtration chromatography and reversed phase high performance liquid chromatography.The purified substance was stable to alkaline,heat,protease and UV.It could dissolve in methanol.The substance showed positive reaction to biuret and negative reaction to ninhydrin,but showed positive reaction to ninhydrin when it was hydrolyzed with acid.All the data above indicated that the substance could be ring peptide.The growth of 14 plant pathogens could be inhibit by the substance,among which,the pathogens of the northern corn leaf blight,southern corn leaf blight and banana leaf spot were inhibited strongly,while no inhibition to the tested bacterial pathogens.Control efficacy of antimicrobial substance produced by Bacillus subtilis B47 at 0.3 g·L-1 on the southern corn leaf blight in field was 53.05%.

  13. Effect of Trichoderma harzianum biomass and Bradyrhizobium sp. strain NC 92 to control leaf blight disease of bambara groundnut (Vigna subterranea caused by Rhizoctonia solani in the field

    Directory of Open Access Journals (Sweden)

    Mana Kanjanamaneesathian

    2007-01-01

    Full Text Available Four hundred and sixty two strains of Trichoderma spp. were isolated from 23 soil samples in which groundnut (Arachis hypogaea L. and bambara groundnut (Vigna subterranea L. had been planted in Songkhla, Phattalung, Nakhon Si Thammarat, Narathiwat and Yala provinces. These fungi were tested against Rhizoctonia solani, a causal agent of leaf blight of bambara groundnut, using dual culture technique on PDA medium. Among 462 isolates tested, 226 isolates had an ability to overgrow R. solani completely. Further testing found 13 isolates having the ability to parasitize mycelia of R. solani. Among these isolates, ThB-1-54 produced a cellulolytic enzyme on congo-red agar. This isolate was later identified as T. harzianum Rifai. In the field test, applying biomass of the isolate ThB-1-54 cultured on ground mesocarp fiber of oil palm, the combination of the isolate ThB-1-54 on ground mesocarp fiber of oil palm and Bradyrhizobium sp. (strain NC 92, or fungicide (iprodione had no effect on disease severity, yield, or the amount of total nitrogen content in stems or seeds of bambara groundnut plant.

  14. Bacterial brown leaf spot of citrus, a new disease caused by Burkholderia andropogonis

    Science.gov (United States)

    A new bacterial disease of citrus was recently identified in Florida and named as bacterial brown leaf spot (BBLS) of citrus. BBLS-infected citrus displayed flat, circular and brownish lesions with water-soaked margins surrounded by a chlorotic halo on leaves. Based on Biolog carbon source metabolic...

  15. Jasmonate induction of the monoterpene linalool confers resistance to rice bacterial blight and its biosynthesis is regulated by JAZ protein in rice.

    Science.gov (United States)

    Taniguchi, Shiduku; Hosokawa-Shinonaga, Yumi; Tamaoki, Daisuke; Yamada, Shoko; Akimitsu, Kazuya; Gomi, Kenji

    2014-02-01

    Jasmonic acid (JA) is involved in the regulation of host immunity in plants. Recently, we demonstrated that JA signalling has an important role in resistance to rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice. Here, we report that many volatile compounds accumulate in response to exogenous application of JA, including the monoterpene linalool. Expression of linalool synthase was up-regulated by JA. Vapour treatment with linalool induced resistance to Xoo, and transgenic rice plants overexpressing linalool synthase were more resistance to Xoo, presumably due to the up-regulation of defence-related genes in the absence of any treatment. JA-induced accumulation of linalool was regulated by OsJAZ8, a rice jasmonate ZIM-domain protein involving the JA signalling pathway at the transcriptional level, suggesting that linalool plays an important role in JA-induced resistance to Xoo in rice.

  16. 桉树焦枯病菌(Calonectria pseudoreteaudii)生物学特性测定%Biological characteristics of Calonectria pseudoreteaudii associated with Cylindrocladium leaf blight

    Institute of Scientific and Technical Information of China (English)

    陈全助; 陈慧洁; 郭文硕; 叶小真; 沈金清

    2014-01-01

    丽赤壳属多数种是桉树焦枯病( Cylindrocladium leaf blight)重要致病菌,掌握病原菌生物学特性有助于从病原角度了解病害发生发展,科学指导防治。对桉树焦枯病致病菌株Calonectria pseudoreteaudii生物学特性进行测定。结果表明:该菌株菌丝生长以燕麦片琼脂培养基生长最快,最适温度为24-26℃,最适pH值为7.0,而光照条件不影响菌丝生长;菌株产孢最适温度为25℃,最适pH值为6.0,以光照、PDA培养基产孢量较高;分生孢子萌发与相对湿度成正相关,最适温度为28℃,最适pH值为6.0,黑暗有助于孢子萌发。%Absrt act:Calonectria spp., particularly in their Cylindrocladium anamorph form, are well-known pathogens associated with Cylin-drocladium leaf blight.For the purpose of understanding the biological characteristics of Ca.pseudoreteaudii YA5j2 and guiding how to control this disease, biological characteristics of this isolate were determined.The optimal conditions for mycelium growth were oatmeal agar medium with pH 7.0 cultivated at 24-26℃, and illuminance had no significant effect on hyphae growth.The suitable conditions for spore production were potato dextrose agar medium with pH 6.0 cultivated at 25℃in the light.Conidium germination had a positive correlation with relative humidity, and conidium under the circumstance with high humidity, pH 6.0, temperature at 28 ℃, and without illumination contributed to germination.

  17. 钟山县甜玉米大小斑病流行分析及防治对策%Epiphytotic analysis and control countermeasures of northern and southern leaf blight on sweet corn in Zhongshan County

    Institute of Scientific and Technical Information of China (English)

    钟珍秀

    2011-01-01

    This paper analyzes the characteristics,occurrence regularity and causes of northern and southern leaf blight on sweet corn in Yantang Township of Zhongshan County.According to the local conditions,the corresponding cultivation technical measures have bee%通过对钟山县燕塘镇甜玉米大小斑病的流行特点和发生规律及原因进行分析,根据当地实际提出相应的栽培技术措施,把大小斑病对甜玉米的危害降到最低限度。

  18. Identification of Pathogens Causing Common Bacterial Blight on Common Bean (Phaseolus vulgaris L.)%菜豆普通细菌性疫病病原菌鉴定

    Institute of Scientific and Technical Information of China (English)

    陈泓宇; 徐新新; 段灿星; 王述民; 朱振东

    2012-01-01

    [目的]明确中国北方地区菜豆普通细菌性疫病病原菌.[方法]应用菌落特征、油菜黄单胞菌菜豆变种诊断试剂检测、致病性测定、16SrDNA和16S-23SrDNA ITS序列分析、特异PCR检测、脂肪酸分析及生理生化反应特征对病原菌分离物进行鉴定.[结果]从病害样品和菜豆种子样品中均分离到类似黄单胞杆菌的细菌分离物,选取25个代表分离物进行致病性测定,有24个分离物在菜豆品种“英国红”上导致典型菜豆普通细菌性疫病症状.结合16S rDNA及16S-23S rDNA ITS序列比对分析、特异性PCR检测及生理生化反应的结果,24个分离物中7株被鉴定为地毯草黄单胞菌菜豆变种,17株为褐色黄单胞菌褐色亚种.[结论]中国北方地区发生的菜豆普通细菌性疫病由地毯草黄单胞菌菜豆变种或(和)褐色黄单胞菌褐色亚种引起;褐色黄单胞菌褐色亚种在中国属首次报道.%[ Objective ] The objective of this study is to identify the pathogens that cause common bacterial blight on common bean in north China. [Method) The causal agents were identified by colony characterization, detection using Xanthomonas campestris pv. phaseoli diagonsis kit (ADGEN EXPRESS, pathogenicity test, sequencing 16 rDNA and 16S-23S rDNA intergenic spacer (ITS) regions, PCR detection using specific primers for X. axonopodis pv. Phaseoli and X. fuscans subsp. Fuscans, fatty acid methyl esters (FAME) analysis and biochemical characterization tests. [Result] Bacterial isolates of Xanthmonads-like were isolated from all diseased plant and seed samples. Twenty-five representative isolates were selected for pathogenicity test, and 24 tested isolates casused typical symptoms of common bacterial blight on the inoculated plants of common bean cutivar 'Yingguohong'. Based on pathenogenicity test, and combined with the results of diagonsis kit and specific PCR detection, biochemical and molecular characterization, 7 isoaltes were

  19. Toward the positional cloning of qBlsr5a, a QTL underlying resistance to bacterial leaf streak, using overlapping sub-CSSLs in rice.

    Directory of Open Access Journals (Sweden)

    Xiaofang Xie

    Full Text Available Bacterial leaf steak (BLS is one of the most destructive diseases in rice. Studies have shown that BLS resistance in rice is quantitatively inherited, controlled by multiple quantitative trait loci (QTLs. A QTL with relatively large effect, qBlsr5a, was previously mapped in a region of ∼ 380 kb on chromosome 5. To fine map qBlsr5a further, a set of overlapping sub-chromosome segment substitution lines (sub-CSSLs were developed from a large secondary F2 population (containing more than 7000 plants, in which only the chromosomal region harboring qBlsr5a was segregated. By genotyping the sub-CSSLs with molecular markers covering the target region and phenotyping the sub-CSSLs with artificial inoculation, qBlsr5a was delimited to a 30.0-kb interval, in which only three genes were predicted. qRT-PCR analysis indicated that the three putative genes did not show significant response to the infection of BLS pathogen in both resistant and susceptible parental lines. However, two nucleotide substitutions were found in the coding sequence of gene LOC_Os05g01710, which encodes the gamma chain of transcription initiation factor IIA (TFIIAγ. The nucleotide substitutions resulted in a change of the 39th amino acid from valine (in the susceptible parent to glutamic acid (in the resistant parent. Interestingly, the resistant parent allele of LOC_Os05g01710 is identical to xa5, a major gene resistant to bacterial leaf blight (another bacterial disease of rice. These results suggest that LOC_Os05g01710 is very possibly the candidate gene of qBlsr5a.

  20. A Study on The Genetic Diversity of Rice Leaf Blight Pathogen%水稻条斑病菌遗传多样性研究

    Institute of Scientific and Technical Information of China (English)

    周丽洪; 杨俊; 李淼; 姬广海

    2014-01-01

    为更好监测条斑病菌的流行和鉴定其区域性的群体结构,本研究比较了利用鉴别寄主、毒性相关基因差异、可变数目串联重复序列3种方法对条斑病菌进行小种分类的优劣。结果显示:利用可变数目串联重复序列进行条斑病菌进行小种分类具有快速有效且精准方便的优势;利用10个可变数目串联重复序列位点分析全国40份菌株,10个VNTR均具有多样性,聚类分析显示:利用多个可变数目串联重复序列进行条斑病菌遗传多样性研究技术,是一种快速而有效的研究技术,能反映出条斑病菌株水平的基因型、系统发育和分类学关系,可应用于种以下水平的分类和鉴定。%For the monitoring the prevalence of Xanthomonas oryzae pv.oryzicola and identification of their regional group structure ,this study compared three methods of differential hosts ,toxicity-related genetic differ-ences and avariable number of tandem repeats for race classification .The results showed that:the VNTR was a fast,effective,precise and convenient method for race classification .10 VNTR sites were used to evaluate the 40 strains in China .These 10 VNTR sites were of diversity for cluster analysis .The use of the diversity of VNTR sites for Xoc race classification is a fast and effective technique , which can reflect the level of leaf blight strains’ genotype,the relationship between phylogeney and race classification .

  1. Study on Turf Grass Leaf Blight of Bipolaris sorokiniana.%草坪草离蠕孢叶枯病的研究

    Institute of Scientific and Technical Information of China (English)

    刘振宇; 侯新村; 张志国

    2000-01-01

    Bipolaris sorokiniana能浸染草坪禾草叶片形成梭形病斑,并可导致芽腐、苗枯、根腐、茎基腐、鞘腐等症状;病原菌在10~40℃下能够生长,最适生长温度为25℃;病原菌分生孢子在不同萌发条件中以水平萌发较好;分生孢子萌发需要空气条件,但对营养要求不严格;在20~35℃下分生孢子均可萌发,以28℃下萌发最好;八种不同药剂对病原菌的抑制效果表明,50%施保功可湿性粉剂1500倍液效果较好,其抑菌圈直径和抑制分生孢子萌发率分别为46.2mm和81.3%,其他几种药剂对孢子萌发也有较好的抑制作用。%Bipolaris sorokiniana may affect turf grass to cause leaf spot, bud rot, seedling blight, root rot, sheath rot. The temperature range of colony growth is 10~40℃, the optimum 25℃. Conidia can germinate in the temperature range of 20~35℃, and germinate best at 28℃; Conidia germinate well on slide water surface, contrary to other different methods, and they can germinate well under given air condition, but germination is not strict with nutrition. The inhibiting test of 8 kinds of fungicide showed Sporgon 50WP was most effective, and the inhibiting effect of the others was well to the conidia germination.

  2. 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.

  3. 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.

  4. Frequency, Size, and Localization of Bacterial Aggregates on Bean Leaf Surfaces

    Science.gov (United States)

    Monier, J.-M.; Lindow, S. E.

    2004-01-01

    Using epifluorescence microscopy and image analysis, we have quantitatively described the frequency, size, and spatial distribution of bacterial aggregates on leaf surfaces of greenhouse-grown bean plants inoculated with the plant-pathogenic bacterium Pseudomonas syringae pv. syringae strain B728a. Bacterial cells were not randomly distributed on the leaf surface but occurred in a wide range of cluster sizes, ranging from single cells to over 104 cells per aggregate. The average cluster size increased through time, and aggregates were more numerous and larger when plants were maintained under conditions of high relative humidity levels than under dry conditions. The large majority of aggregates observed were small (less than 100 cells), and aggregate sizes exhibited a strong right-hand-skewed frequency distribution. While large aggregates are not frequent on a given leaf, they often accounted for the majority of cells present. We observed that up to 50% of cells present on a leaf were located in aggregates containing 103 cells or more. Aggregates were associated with several different anatomical features of the leaf surface but not with stomates. Aggregates were preferentially associated with glandular trichomes and veins. The biological and ecological significance of aggregate formation by epiphytic bacteria is discussed. PMID:14711662

  5. TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.

    Science.gov (United States)

    Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

    2013-08-01

    Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat. PMID:23918959

  6. A Comparison of the Molecular Organization of Genomic Regions Associated with Resistance to Common Bacterial Blight in Two Phaseolus vulgaris Genotypes

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    Gregory E. Perry

    2013-08-01

    Full Text Available Resistance to common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli, in Phaseolus vulgaris is conditioned by several loci on different chromosomes. Previous studies with OAC-Rex, a CBB-resistant, white bean variety of Mesoamerican origin, identified two resistance loci associated with the molecular markers Pv-CTT001 and SU91, on chromosome 4 and 8, respectively. Resistance to CBB is assumed to be derived from an interspecific cross with Phaseolus acutifolius in the pedigree of OAC-Rex. Our current whole genome sequencing effort with OAC-Rex provided the opportunity to compare its genome in the regions associated with CBB resistance with the v1.0 release of the P. vulgaris line G19833, which is a large seeded bean of Andean origin, and (assumed to be CBB susceptible.. In addition, the genomic regions containing SAP6, a marker associated with P. vulgaris-derived CBB-resistance on chromosome 10, were compared. These analyses indicated that gene content was highly conserved between G19833 and OAC-Rex across the regions examined (>80%. However, fifty-nine genes unique to OAC Rex were identified, with resistance gene homologues making up the largest category (10 genes identified. Two unique genes in OAC-Rex located within the SU91 resistance QTL have homology to P. acutifolius ESTs and may be potential sources of CBB resistance. As the genomic sequence assembly of OAC-Rex is completed, we expect that further comparisons between it and the G19833 genome will lead to a greater understanding of CBB resistance in bean.

  7. ‘Carolina Broadleaf’ mustard green (Brassica juncea L.) resistant to the bacterial leaf blight pathogen Pseudomonas cannabina pv. alisalensis

    Science.gov (United States)

    A leafy-green mustard (Brassica juncea L.) cultivar designated ‘Carolina Broadleaf’ has been released by the Agricultural Research Service of the U.S. Dept. of Agriculture in 2015. This released cultivar is a narrow-based population of leafy-green mustard derived from a U.S. plant introduction (PI)...

  8. Rizobactérias no controle da mancha angular do algodoeiro Rhizobacteria to control cotton bacterial blight

    Directory of Open Access Journals (Sweden)

    Alessandra Keiko Nakasone Ishida

    2008-02-01

    Full Text Available Avaliou-se o potencial de rizobactérias na indução de resistência do algodoeiro à Xanthomonas axonopodis pv. malvacearum. Após o isolamento das rizobactérias, foram selecionados os isolados capazes de reduzir os sintomas da mancha angular bacteriana em casa de vegetação, os quais foram aplicados espacialmente separados do patógeno desafiador. Os melhores isolados foram testados quanto à capacidade de reduzir os sintomas da ramulose e da murcha de Verticillium e de inibir diretamente os patógenos in vitro. Do total de 123 isolados de rizobactérias foram selecionados cinco, L2-1 (Bacillus cereus, MT5-6 (Bacillus cereus, L2-2 (Achromobacter xylosoxidans, MT5-5 (Bacillus cereus e MT5-11 (Brevibacterium sp., os quais apresentaram controle da mancha angular acima de 40%, em relação à testemunha. Nenhum isolado reduziu a severidade da ramulose e da murcha de Verticillium em relação à testemunha, nem apresentou efeito inibitório direto in vitro a X. axonopodis pv. malvacearum e Colletotrichum gossypii var. cephalosporioides. Para V. dahliae, apenas o isolado L2-1 apresentou efeito inibitório.The potential of rhizobacteria was evaluated for resistance induction against Xanthomonas axonopodis pv. malvacearum. After isolation, the rhizobacteria were screened for the reduction of angular leaf spot severity under greenhouse conditions. They were spatially separated from the challenging pathogen. The best isolates were tested for the capacity to reduce ramulose and Verticillium wilt severity and directly inhibit pathogens in vitro. From a total of 123 rhizobacterial isolates, five were selected, L2-1 (Bacillus cereus, MT5-6 (Bacillus cereus, L2-2 (Achromobacter xylosoxidans, MT5-5 (Bacillus cereus and MT5-11 (Brevibacterium sp., which showed angular leaf spot control above 40% as compared to the control. The tested isolates neither reduced the severity of ramulose and verticillium wilt compared to the control nor showed in vitro direct

  9. Evaluation of pyraclostrobin and acibenzolar-S-methyl on common bacterial blight of snap beanAvaliação de pyraclostrobin e acibenzolar-S-methyl sobre o crestamento bacteriano comum do feijão-vagem

    Directory of Open Access Journals (Sweden)

    Renata de Cássia Camara

    2012-04-01

    Full Text Available Assays were done under greenhouse conditions in order to evaluate the effect of pyraclostrobin (0.0375, 0.0750 and 0.150 mL.L-1 and acibenzolar-S-methyl (ASM (0.025 g.L-1 in common bacterial blight, using leaves of snap beans cultivar Bragança. These chemicals were sprayed at three different times: five days before; five days before + five days after; and five days after leaf inoculation with an isolate of Xanthomonas axonopodis pv. phaseoli. They were determinate the levels of polyphenoloxidase, peroxidase and total soluble proteins on inoculated and non-inoculated leaves of snap beans sprayed with pyraclostrobin (0.075 g.L-1 and ASM (0.025 g.L-1. All concentration of pyraclostrobin and ASM reduced the area under the disease progress curve (AUDPC on leaves of snap beans, and the least AUDPC value was observed when this products were sprayed five days before + five days after inoculation. Higher levels of polyphenoloxidase, peroxidase and the total soluble proteins were observed on leaves sprayed with pyraclostrobin or ASM.Ensaios foram conduzidos sob condições de casa-de-vegetação para avaliar o efeito de pyraclostrobin (0,0375; 0.0750 e 0,150 mL.L-1 e acibenzolar-S-methyl (ASM (0.025 g.L-1 sobre o crestamento bacteriano comum, em folhas de feijão-vagem cultivar Bragança. Os produtos foram pulverizados em três diferentes períodos: cinco dias antes, cinco dias antes + cinco dias após e cinco dias após a inoculação dos folíolos com um isolado de Xanthomonas axonopodis pv. phaseoli. Foram determinados os teores de polifenoloxidase, peroxidase e proteínas solúveis totais em folhas inoculadas e não-inoculadas de feijão-vagem pulverizadas com pyraclostrobin (0,075 g.L-1 e ASM (0,025 g.L-1. Todas as concentrações de pyraclostrobin e ASM reduziram os valores da área abaixo da curva do progresso da doença (AUPDC e o menor valor da AUPDC foi observado para a aplicação dos produtos cinco dias antes + cinco dias após a inocula

  10. Antibacterial activity of plant extracts against Xanthomonas axonopodis Pv. Punicae causing bacterial blight of Pomegranate (Punica granatum L.

    Directory of Open Access Journals (Sweden)

    Alane S K

    2016-01-01

    Full Text Available Pomegranate (Punica granatum L. is the important fruit crop cultivated throughout the world. It is famous for its refreshing fruits. The crop is affected by ‘bacterial blight’ caused by Xanthomonas axonopodis pv. punicae, which is responsible for the failure of crop. It results in the dropping of leaves as well as fruits. It is very hard to manage the disease with chemicals as well as antibiotics and farmers suffer from heavy economic losses. In the present study, aqueous, ethyl alcohol and acetone extracts of ten medicinally useful plants were used against Xanthomonas axonopodis pv. punicae in vitro. The plant extracts showed antibacterial activity and caused inhibition of growth of Xanthomonas axonopodis pv. Punicae. Among them, Mentha spicata, Murraya Koeninngi, Allium sativum and Tridax procumbens caused maximum inhibition of the test bacterium.

  11. Identification and Biological Characteristics of Fusarium verticillioides (Saccardo)Nirenberg Causing Leaf Blight on TiPlant(Cordvline fruticosa Chevalier)%朱蕉叶枯病菌的鉴定及生物学特性

    Institute of Scientific and Technical Information of China (English)

    童依婷; 晏冬华; 彭文煊; 黄静华; 黄洪滨; 易润华

    2016-01-01

    通过致病性测定、形态学特性和系统发育分析,确定引起朱蕉叶枯病的病原菌为轮状镰刀菌 Fusarium verticillioides(Saccardo) Nirenberg。研究表明,在测试的7种培养基中,PDA最有利于病原菌生长,PSCA最有利于产孢。以蜂蜜为碳源的培养基上生长最快,产孢量最大,而以柠檬酸钠作碳源时生长最慢,产孢量最小;以蛋白胨为氮源时生长最快,而以酵母膏为氮源时产孢量最大。病原菌的最适生长和产孢的温度为25℃,在pH值为8时生长速率最快,pH值为7时产孢量最大。光照对病原菌生长影响差异显著,对产孢量影响差异不显著。%The pathogen of leaf blight on ti plant(Cordyline fruticosa Chevalier)was recognized as Fusarium verticillioides(Saccardo)Nirenberg according to thepathogenicity tests,the biological characteristics and phylogenetic analysis.The results of biological characteristics showed that among the seven tested media, the pathogen grew fastest and sporulated richest on potato dextrose agar(PDA) medium and potatosugarCordyline fruticosa leaf agar(PSCA);the Czapek–Dox medium(CDM) with equal quality of honey to substitute as carbon source was most favorable for the mycelial growth and sporulation ofF. verticillioides, while with sodium citrate was most unfavorable among the eleven tested carbon sources;thebestnitrogen source for the mycelial growth and sporulation were peptone and yeast extract respectively among the tested nitrogen sources;thetemperature25℃wasoptimumfor the mycelial growth and sporulation;the mycelial growth was encouraged by pH 8.0 and the sporulation was by pH 7.0;light treatments had no significant effect onthe sporulation butit hadsignificant onthe mycelial growth of the pathogen of leaf blight on ti plant.

  12. Research Progress of Spikelet Rot Disease and Bacterial Panicle Blight of Rice%水稻穗腐病和穗枯病的研究进展

    Institute of Scientific and Technical Information of China (English)

    李路; 刘连盟; 王国荣; 汪爱娟; 王玲; 孙磊; 黎起秦; 黄世文

    2015-01-01

    水稻穗腐病和穗枯病是我国新上升或新出现的两个水稻后期穗部病害。近年来,随着气候的变化、耕作栽培制度及肥水管理的改变以及品种(组合)的更替,两病在我国的发生和危害程度越来越严重。穗腐病和穗枯病病原菌有色,可产生毒素,不但直接影响水稻产量,还导致稻米品质降低,危害食用者的健康。穗腐病和穗枯病在发病时期、发生部位和危害程度上具有相似性。综述了两病害的发生、流行规律、危害状况、病原菌生物特性和毒素研究以及防治方法,提出了研究上目前存在的问题和今后的研究方向。%Rice spikelet rot disease (RSRD)and bacterial panicle blight of rice (BPBR),two newly increasing or emerging diseases in China,are both panicle diseases in the late growth stage of rice.The diseases have become more and more serious in recent years due to the changes of climate,cultivation system,nutrient and water management as well as the substitute of rice varieties/combinations.The RSRD and BPBR not only affected rice yield directly but also decreased rice quality due to the colourful pathogens and pathogenic toxins.The toxins were also noxious to the animals and human beings.The two diseases have similarities in epidemic period,infected parts of rice and the damage degree. The regularity of the diseases’occurrence and epidemiology,the damage status,the investigation of pathogens’ biological characteristics and their toxins,the control approaches in paddy fields were briefly reviewed.We pointed out the issues existed in current research and the research directions of these two diseases in the future.

  13. 水稻穗腐病和穗枯病的研究进展%Research Progress of Spikelet Rot Disease and Bacterial Panicle Blight of Rice

    Institute of Scientific and Technical Information of China (English)

    李路; 刘连盟; 王国荣; 汪爱娟; 王玲; 孙磊; 黎起秦; 黄世文

    2015-01-01

    水稻穗腐病和穗枯病是我国新上升或新出现的两个水稻后期穗部病害。近年来,随着气候的变化、耕作栽培制度及肥水管理的改变以及品种(组合)的更替,两病在我国的发生和危害程度越来越严重。穗腐病和穗枯病病原菌有色,可产生毒素,不但直接影响水稻产量,还导致稻米品质降低,危害食用者的健康。穗腐病和穗枯病在发病时期、发生部位和危害程度上具有相似性。综述了两病害的发生、流行规律、危害状况、病原菌生物特性和毒素研究以及防治方法,提出了研究上目前存在的问题和今后的研究方向。%Rice spikelet rot disease (RSRD)and bacterial panicle blight of rice (BPBR),two newly increasing or emerging diseases in China,are both panicle diseases in the late growth stage of rice.The diseases have become more and more serious in recent years due to the changes of climate,cultivation system,nutrient and water management as well as the substitute of rice varieties/combinations.The RSRD and BPBR not only affected rice yield directly but also decreased rice quality due to the colourful pathogens and pathogenic toxins.The toxins were also noxious to the animals and human beings.The two diseases have similarities in epidemic period,infected parts of rice and the damage degree. The regularity of the diseases’occurrence and epidemiology,the damage status,the investigation of pathogens’ biological characteristics and their toxins,the control approaches in paddy fields were briefly reviewed.We pointed out the issues existed in current research and the research directions of these two diseases in the future.

  14. Phenotypic and biochemical characterisation of the causal agent of bacterial leaf streak of maize / Nienaber

    OpenAIRE

    Nienaber, Jesse Jay

    2015-01-01

    Maize is the staple food for a majority of people in Southern Africa, but plant diseases are responsible for at least 10% of crop production losses. Bacterial leaf streak (BLS) of maize was first reported in South Africa in 1949 and has not been reported elsewhere. Very little is known about the pathogen involved and therefore it is deemed necessary to compile a characteristic profile for the pathogen to prevent the possibility of major crop losses as a result of this disease. This study a...

  15. Bacterial Blight Resistance Genes Anchored to Physics Map of Rice Genome%水稻抗白叶枯病基因在物理图谱上的锚定

    Institute of Scientific and Technical Information of China (English)

    鲍思元

    2013-01-01

    到目前为止,经国际注册确认和期刊报道的水稻白叶枯病抗性基因共35个.已被定位的抗性基因有26个,即第1染色体上有2个,Xa29(t)和xa34(t);第3染色体上有Xa11;第4染色体上有6个,Xa1、Xa2、Xa12、Xa14、Xa25(t)、Xa31(t);第5染色体上有xa5;第6染色体上有3个,Xa7、Xa27(t)、xa33(t);第7染色体上有xa8;第8染色体上有xa13;第11染色体上有9个,Xa3/Xa26、Xa4、Xa1O、Xa21、Xa22(t)、Xa23、Xa30(t)、Xa32(t)、Xa36(t);第12染色体上有2个,xa25、xa32(t).Xa1、xa5、xa13、Xa21、Xa23、xa25、Xa26、Xa27已成功克隆.文中利用GRAMENE网站公布的抗白叶枯病基因的分子标记,在日本晴的测序图谱Gramene Annotated NipponbareSequence2009上进行物理图谱锚定,将已定位的26个抗白叶枯病基因锚定在其物理图谱的26个位点上,为抗白叶枯病基因的基因克隆、分子标记辅助选择奠定了基础.%Up to the present day, there are a total of 35 bacterial blight resistance genes registered internationally or reported in international journals. Among them, 26 genes were mapped, including Xa29(t) , xa34(t) on chromosome 1; Xall on chromosome 3; Xal, Xal, XaYl, Xal4, Xa25(t) , Xa31(t) on chromosome 4; xa5 on chromosome 5; Xal, Xall(t) , xa33(t) on chromosome 6; xd& on chromosome 7; xal3 on chromosome 8; Xa3/Xa26, XaA, XaW, Xa21 , Xa22(t) , Xa23, Xa30(t) , Xa32(t) , Xa36(t) on chromosome 11; xa25, xa32(t) on chromosome 12. 8 bacterial blight resistance genes were cloned, including Xal, xa5, xal3 , Xa21 , Xa23, xa25 , Xa26 and Xa21. Molecular markers of bacterial blight resistance genes from GRAMENE website were anchored to the physics map of Gramene Annotated Nipponbare Sequence 2009. 26 bacterial blight resistance genes were anchored to the physics map 26 units place through this research. The work laid the foundation for cloning bacterial blight resistance genes and the marker-assisted selection in breeding programs.

  16. 广西桂花叶枯病病原菌鉴定及其生物学特性研究%Identification and Characterization of Causal Agent of Sweet Osmanthus Leaf Blight in Guangxi

    Institute of Scientific and Technical Information of China (English)

    谢玲; 唐晨光; 岑贞陆; 黄思良; 秦碧霞; 覃丽萍; 胡春锦

    2009-01-01

    A sweet osmanthus leaf blight severely occurred in Nanning city, Guangxi, China. The pathogen was isolated and its pathogenicity to sweet osmanthus plants confirmed by inoculation tests. The pathogenic isolate CHS was identified as Alternaria alternata (Fr.)Keissler based on its morphological characteristics and ITS sequence. The optimum temperature and pH value for growth and conidial germination were 28 ℃ and 6-7, respectively. Different conditions of light showed no obvious effect on the mycelial growth. Black light was favorable for conidial production. Tests on fungicidal sensitivity in vitro showed that the pathogen was highly sensitive to difenoconazole, prochloraz and propiconazole. This is the first record of sweet osmanthus leaf blight caused by A. alternata in Guangxi.%在广西南宁桂花树上严重发生一种叶枯病,从病叶上分离到桂花叶枯病菌(编号CHS),在致病性测定的基础上,根据病原菌株CHS的形态及ITS序列,将其鉴定为Alternaria alternata(Fr.)Keissler.对该菌的生物学特性研究结果表明:菌丝生长、孢子形成和孢子萌发的最适温度均为28 ℃;生长发育最适pH值为6~7;不同光环境对该菌菌丝生长发育影响不大,黑光环境最利于孢子萌发;在供试的培养基中PDA最适合菌丝生长和产孢;苯醚甲环唑、咪鲜胺和丙环唑对该菌的抑制作用最强.由A. alternata引起的桂花叶枯病在广西的发生属首次报道.

  17. Effect on the Occurrence and Epidemic of Corn Northern Leaf Blight in Two-plant Cultivation Mode%双株栽培模式对玉米大斑病流行时间动态影响

    Institute of Scientific and Technical Information of China (English)

    傅俊范; 刘震; 景殿玺; 周如军; 薛彩云

    2014-01-01

    The two-plant cultivation mode is the production of corn in Liaoning province on the new cultivation mode, which consists of two-plant orientation cultivation mode and two-plant abutted cultivation mode. According to the principles of plant disease epidemiology, epidemic dynamics of Northern Leaf Blight of corn was comparative-ly studied among two-plant orientation cultivation mode, two-plant abutted cultivation mode and conventional culti-vation mode, by using field experimental design and artificial inoculation technique. The research showed that the disease indexes in two-plant orientation cultivation mode and two-plant abutted cultivation mode were lower than conventional cultivation mode. By comparative analysis with SPSS 11.5, Logistic model is suitable for describing the epidemic dynamics of Northern Leaf Blight in the two-plant orientation cultivation mode, two-plant abutted cultiva-tion mode and conventional cultivation mode.%双株栽培模式是辽宁省玉米生产的新型栽培模式,包括双株定向栽培模式和双株紧靠栽培模式。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,对双株定向栽培模式、双株紧靠栽培模式和常规栽培模式下玉米大斑病发生流行动态进行比较研究。调查研究发现,双株定向栽培模式和双株紧靠栽培模式的病情指数低于常规栽培模式。通过SPSS 11.5软件对比分析,Logistic模型适用于描述双株定向栽培模式、双株紧靠栽培模式和常规栽培模式下玉米大斑病流行时间动态。

  18. Spatial Organization of Dual-Species Bacterial Aggregates on Leaf Surfaces

    Science.gov (United States)

    Monier, J.-M.; Lindow, S. E.

    2005-01-01

    The spatial organization of cells within bacterial aggregates on leaf surfaces was determined for pair-wise mixtures of three different bacterial species commonly found on leaves, Pseudomonas syringae, Pantoea agglomerans, and Pseudomonas fluorescens. Cells were coinoculated onto bean plants and allowed to grow under moist conditions, and the resulting aggregates were examined in situ by epifluorescence microscopy. Each bacterial strain could be localized because it expressed either the green or the cyan fluorescent protein constitutively, and the viability of individual cells was assessed by propidium iodide staining. Each pair of bacterial strains that was coinoculated onto leaves formed mixed aggregates. The degree of segregation of cells in mixed aggregates differed between the different coinoculated pairs of strains and was higher in mixtures of P. fluorescens A506 and P. agglomerans 299R and mixtures of P. syringae B728a and P. agglomerans 299R than in mixtures of two isogenic strains of P. agglomerans 299R. The fractions of the total cell population that were dead in mixed and monospecific aggregates of a gfp-marked strain of P. agglomerans 299R and a cfp-marked strain of P. agglomerans 299R, or of P. fluorescens A506 and P. agglomerans 299R, were similar. However, the proportion of dead cells in mixed aggregates of P. syringae B728a and P. agglomerans 299R was significantly higher (13.2% ± 8.2%) than that in monospecific aggregates of these two strains (1.6% ± 0.7%), and it increased over time. While dead cells in such mixed aggregates were preferentially found at the interface between clusters of cells of these strains, cells of these two strains located at the interface did not exhibit equal probabilities of mortality. After 9 days of incubation, about 77% of the P. agglomerans 299R cells located at the interface were dead, while only about 24% of the P. syringae B728a cells were dead. The relevance of our results to understanding bacterial interactions

  19. EXPRESIÓN DE DOS GENES CANDIDATOS A RESISTENCIA CONTRA LA BACTERIOSIS VASCULAR EN YUCA Expression Of Two Resistance Gene Candidates Against Cassava Bacterial Blight In Cassava

    Directory of Open Access Journals (Sweden)

    ELÍZABETH CONTRERAS NIETO

    Full Text Available La yuca (Manihot esculenta Crantz, Euphorbiaceae es el cuarto cultivo en importancia a nivel mundial como fuente de calorías para la población humana y cuya producción se ve afectada por la bacteriosis vascular, enfermedad ocasionada por Xanthomonas axonopodis pv. manihotis (Xam. La resistencia a enfermedades en plantas depende de la presencia de genes de resistencia (R, los cuales reconocen a los patógenos y simultáneamente permiten desencadenar la respuesta de defensa. A pesar de recientes esfuerzos encaminados a la identificación de genes R en yuca, aún no se ha logrado clonar el primer gen R en este cultivo. En el presente trabajo se estudió el perfil de expresión de dos Genes Candidatos a Resistencia (RGCs asociados a QTLs de defensa contra la bacteriosis vascular en yuca. A partir de la técnica transcripción reversa y reacción en cadena de la polimerasa (RT-PCR se evaluó la expresión de los genes RXam1 y RXam2 en tallos y hojas de las variedades resistentes SG107-35 y MBRA685 de yuca, después de ser inoculadas con la cepa CIO151 de Xam. Se observó que RXam1 es inducido a partir de los cinco días post-inoculación tanto en tallos como hojas de las dos variedades, mientras que RXam2 es expresado de manera constitutiva en la variedad MBRA685.Cassava (Manihot esculenta Crantz, Euphorbiaceae is the fourth food crop used as an important energy source for human population worldwide. Cassava Bacterial Blight (CBB is the most important disease of this crop. CBB is caused by the pathogenic bacterium Xanthomonas axonopodis pv. manihotis (Xam. Plants have developed sophisticated mechanisms to detect and respond to infection by pathogens. These mechanisms depend on the presence of resistance (R genes, which recognize proteins produced by pathogens. Although efforts have been conducted to identify R genes in cassava, the first R gene in this crop has not been cloned. The present work studied the expression profile of two resistance gene

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

    OpenAIRE

    Ren, Gaidi; Zhang, Huayong; Lin, Xiangui; Zhu, Jianguo; Jia, Zhongjun

    2015-01-01

    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 fertilizatio...

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

    OpenAIRE

    Gaidi eRen; Huayong eZhang; Xiangui eLin; Jianguo eZhu; Zhongjun eJia

    2015-01-01

    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...

  2. 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.

  3. 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

    2016-01-01

    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. PMID:27493604

  4. 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. PMID:27493604

  5. 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...

  6. Evaluation of assembling methods on determination of whole genome sequence of Xylella fastidiosa blueberry bacterial leaf scorch strain

    Science.gov (United States)

    Blueberry bacterial leaf scorch (BBLS) disease, a threat to blueberry production in the Southern USA and potentially elsewhere, is caused by Xylella fastidiosa. Efficient control of BBLS requires knowledge of the pathogen. However, this is challenging because Xylella fastidiosa is difficult to cultu...

  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. 玉米大斑病感、抗近等基因系SNP基因芯片分析%SNP Gene Chip Analysis of Near-isogenic Lines to North Corn Leaf Blight

    Institute of Scientific and Technical Information of China (English)

    马骏; 王延波; 刘欣芳; 李明; 弓雪; 齐欣; 姜敏

    2014-01-01

    A pair near-isogenic lines of north corn leaf blight using of SNP gene chip(56 110 SNP) was ana-lyzed. Through bioinformatics and comparative genomics analysis, potential genes screening and function prediction were performed. Thirty-nine SNP were identified associated with resistance, ten candidate area were positioned, lo-cated bin2.06, 3.02/3.03, 3.04, 3.07, 3.08, 7.03 and bin9.08. Twenty-four candidate genes were digged out. The function included a variety of kinase activity, metal ion,energy metabolism and balance.%通过SNP基因芯片(56110个SNP)对A619感、A619Ht3抗玉米大斑病近等基因系进行分析,采用生物信息学和比较基因组学方法进行显著SNP位点候选基因筛查和功能预测。结果表明,发现10个热点区域,分别位于bin2.06、3.02/3.03、3.04、3.07、3.08、7.03和bin9.08,38个SNP被确定与大斑病抗性相关;挖掘出24个候选基因,通过注释发现,候选基因多与各种受体类酶活性、金属离子及能量的代谢和平衡等功能相关。

  9. A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight Revisión sobre el hongo Microcyclus ulei, agente causal del mal suramericano de la hoja del caucho

    Directory of Open Access Journals (Sweden)

    Ancízar Aristizábar Fabio

    2006-12-01

    Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.El hongo ascomycete Microcyclus ulei es el agente causal del SALB que es una de las enfermedades más importan­tes del árbol de caucho natural (Hevea brasiliensis en América Latina y ha sido responsable de numerosas pérdidas económicas. Este hongo ha presentado alta variabilidad fisiológica y se sugiere su alta adaptabilidad, dentro de los mecanismos asociados a su virulencia se ha descrito la tolerancia al HCN. Se han obtenido clones de Hevea resistentes mediante mejoramiento genético, sin embargo, aun no son bien conocidos los mecanismos asociados a ésta. Un mayor conocimiento de este patógeno permitirá el desarrollo de nuevas estrategias de control así como el mayor entendimiento de los mecanismos asociados a resistencia del hospedero. Palabras clave: Microcyclus ulei, SALB, Hevea brasiliensis.

  10. Preparation and evaluation of Bacillus megaterium-alginate microcapsules for control of rice sheath blight disease.

    Science.gov (United States)

    Wiwattanapatapee, R; Chumthong, A; Pengnoo, A; Kanjanamaneesathian, M

    2013-08-01

    Bacillus megaterium encapsulated in calcium alginate microcapsules was prepared and tested for its efficacy against sheath blight disease of rice. In laboratory conditions, the aqueous suspension (1:100, v/v in potato dextrose agar) of the bacterial microcapsules (10(10) spores/ml) inhibited mycelial growth of Rhizoctonia solani (>99 %) after the microcapsules were produced and stored for 12 months at room temperature (28 ± 2 °C). The survival of the bacterium in the microcapsules in response to ultraviolet (u.v.) irradiation and high temperature was investigated. The survivability of the bacterium in the encapsulated form was greater than that of the fresh cells when it was subjected to u.v. (20-W General electric u.v. lamp from a 25 cm distance for 48 h) and a high temperature treatment (80 °C for 48 h). Cells of the bacterium were detected by scanning electron microscope on both the leaf sheath and the leaf blade (in pot tests in a greenhouse) after spraying encapsulated product. The number of bacteria on the surface of both rice tissues (5 Log. number/g of plant) after spraying with encapsulated product was not significantly different from that after spraying with fresh cells onto the rice seedlings. Spraying the encapsulated B. megaterium on rice plants in the greenhouse was as effective as spraying a chemical fungicide for suppressing rice sheath blight disease. PMID:23508397

  11. 水稻白叶枯病抗性基因的鉴定、定位、克隆与育种应用%Identification, Mapping, Isolation of the Genes Resisting to Bacterial Blight and Their Breeding Application in Rice

    Institute of Scientific and Technical Information of China (English)

    夏春; 陈红旗; 朱旭东

    2012-01-01

    Bacterial blight, caused by Xanthomonas oryzae pv. Oryzae, is the most devastating plant bacterial disease in Asia. Exploration, identification and utilization of new resistant germplasms to rice breeding are the effective pathway to control the disease. Mapping and cloning the resistant genes makes MAS (marker-assisted selection) and transgenic technology play a great role in breeding program for disease resistance and let people have a profound insight on molecular mechanism of resistance to bacterial blight. In this paper, mapping, cloning and application of the genes resisting to bacterial blight were summarized, and also some suggestion was put forward to relieve the damaging extent caused by bacterial blight via utilizing disease resistant breeding program.%水稻白叶枯病是由黄单胞杆菌水稻变种(Xanthomonas oryzae pv.oryzae Xoo)引起的细菌性病害,发掘、鉴定和利用新抗源是控制水稻白叶枯病的有效途径.白叶枯抗性基因定位和克隆,使分子标记辅助选择和转基因技术在白叶枯抗病育种中发挥了重大作用,也使人们在分子水平对白叶枯病抗性机制有了深刻认识.文章综述了白叶枯病抗性基因定位,克隆以及在育种方面的应用,并对如何利用抗病育种减轻白叶枯病的危害提出了几点建议.

  12. 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.

  13. 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.

  14. 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.

  15. 水稻白叶枯病抗性基因及其分子标记辅助选择育种研究进展%Research Progress in Resistant Genes to Bacterial Blight of Rice and Its Molecular Marker Assisted Selection

    Institute of Scientific and Technical Information of China (English)

    毛凌华; 聂元元; 李瑶; 吴晓峰; 陈胜军; 李永辉; 卢明; 黄仁良; 蔡耀辉

    2011-01-01

    综述了白叶枯病抗性基因的克隆与定位研究进展,并介绍了几种具有重要利用价值的抗性基因的应用前景,以及水稻白叶枯病抗性基因工程育种的发展前景和存在的问题.%The authors summarized the research progress in the cloning and mapping of genes resistant to rice bacterial blight, introduced the application prospects of several resistant genes,which had important value in use, and put forward the developmental prospects and existing problems of the genetic engineering breeding of rice resistant to bacterial blight.

  16. Bacterial leaf spot of radicchio (Cichorium intybus) is caused by Xanthomonas hortorum

    Science.gov (United States)

    Beginning in 2002 a leaf spot disease of radicchio (Cichorium intybus) was observed in Monterey County, California. Lesions were maroon to dark brown in color; in some cases the margins of brown lesions became dark maroon with aging. Each leaf spot was observable from both adaxial and abaxial leaf s...

  17. The Preliminary Study on the Control of Southern Corn Leaf Blight by Trichoderma harzianum SH2303%哈茨木霉SH2303防治玉米小斑病的初步研究

    Institute of Scientific and Technical Information of China (English)

    马佳; 范莉莉; 傅科鹤; 余传金; 李雅乾; 陈捷

    2014-01-01

    Trichoderma harzianum SH2303 with high biocontrol activity against southern corn leaf blight (SCLB) was isolated from field soil. Pretreated detached maize leaves with T. harzianum SH2303 showed induced resistance to SCLB with a duration of 15 days. Efficacy of T. harzianum SH2303 against SCLB reached 78.1%and 56.3%under greenhouse and field conditions respectively when spraying spore suspension over maize seedling leaves prior to inoculation of the pathogen. The activities of phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD) in maize leaves peaked at 36 h in the Trichoderma treatments after pathogen challenging inoculation. RNA expression levels of Pal and Sod were also upregulated in pace with the enzyme activity. Results indicated that induced resistance might be one of the important mechanisms in the biocontrol of SCLB by T. harzianum SH2303.%哈茨木霉SH2303是本实验室分离获得的1株具有生防效果的菌株,该菌株能够较好的防治玉米小斑病。通过离体叶片试验确定哈茨木霉SH2303诱导玉米抗小斑病的持效期达15 d。盆栽及大田试验表明,防治玉米小斑病防效分别达到78.1%和56.3%。盆栽试验表明,哈茨木霉 SH2303处理的叶片在挑战接种小斑病菌后第36 h,玉米体内防御反应酶系PAL和SOD活性达到峰值。同时,防御基因Pal和Sod的表达水平也明显上升。综合分析表明,哈茨木霉SH2303的诱导抗性作用是防治玉米小斑病的重要机制之一。

  18. 不同玉米品种对大斑病的抗性与相关防御酶活性的关系研究%Defense Enzyme Activities and the Resistance to Northern Leaf Blight of Different Hybrids in Maize

    Institute of Scientific and Technical Information of China (English)

    王光达; 黄初女; 吴委林; 卜宪娟; 郑大浩

    2014-01-01

    以吉林省玉米早熟、中早熟区种植的4个玉米品种及其亲本为材料,对不同玉米品种对大斑病的抗性与苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和多酚氧化酶(PPO)等3种防御酶活性的关系进行研究。结果表明,3种防御酶PAL、POD和PPO与玉米对大斑病的抗性关系非常密切,玉米植株受大斑病菌侵染后,防御酶活性比对照明显增高。防御酶的作用受品种遗传背景的影响,不同品种中不同防御酶对其大斑病抗性的贡献有差异。受大斑病菌侵染后,抗病性强的品种,PAL和PPO或PAL和POD酶活性发生协同增强,且从抽丝期到灌浆期酶活性协同增强的防御酶不发生酶活性衰减或衰减微弱;感病的品种,从抽丝期到灌浆期存在2种或3种防御酶活性同时衰减现象。%Four maize hybrids and their parental lines widely planted in early-maturity and mid-early maturity zones as materials, relations of the resistance to northern leaf blight in diverse maize hybrids with defense enzyme activities of phenylalnine ammonialyase(PAL), peroxidase(POD) and polyphenoloxidase(PPO) were investigated. The results showed that the activities of defense enzymes PAL, POD and PPO were highly related to maize resis-tance to northern leaf blight. In addition, the defense enzyme activity in maize leaves after infected with northern leaf blight pathogens was obviously increased in comparison with control. The function of these defense enzymes may be affected by genetic backgrounds of maize hybrids, and the contribution of each defense enzyme in an individ-ual hybrid to the resistance to maize northern leaf blight was different. After infected by maize northern leaf blight, for the resistant hybrids, activities of two defense enzymes both PAL and PPO or both PAL and POD were simultane-ously enhanced, and no attenuation of enzyme activity of these defense enzymes at filling stage occurred in compari-son with those at silking

  19. A Single-Tube, Functional Marker-Based Multiplex PCR Assay for Simultaneous Detection of Major Bacterial Blight Resistance GenesXa21, xa13 andxa5 in Rice

    Institute of Scientific and Technical Information of China (English)

    S. K. HAJIRA; M. ANILA; S. BHASKAR; V. ABHILASH; H. K. MAHADEVASWAMY; M. KOUSIK; T. DILIPKUMAR; G. HARIKA; G. REKHA; R. M. SUNDARAM; G. S. LAHA; A. YUGANDER; S. M. BALACHANDRAN; B. C. VIRAKTAMATH; K. SUJATHA; C. H. BALACHIRANJEEVI; K. PRANATHI

    2016-01-01

    In marker-assisted breeding for bacterial blight (BB) resistance in rice, three major resistance genes, viz.,Xa21, xa13andxa5,are routinely deployed either singly or in combinations. As efficient and functional markers are yet to be developed forxa13 andxa5,we have developed simple PCR-based functional markers for both the genes.Forxa13,we designed a functional PCR-based marker, xa13-prom targeting the InDel polymorphism in the promoter of candidate geneOs8N3 located on chromosome 8 of rice. With respect toxa5, a multiplex-PCR based functional marker system, named xa5FM, consisting of two sets of primer pairs targeting the 2-bp functional nucleotide polymorphism in the exon II of the geneTFIIAɤ5 (candidate forxa5), has been developed. Both xa13-prom and xa5FM can differentiate the resistant and susceptible alleles forxa13 andxa5, respectively, in a co-dominant fashion. Using these two functional markers along with the already reported functional PCR-based marker forXa21 (pTA248),we designed a single-tube multiplex PCR based assay for simultaneous detection of all the three major resistance genes and demonstrated the utility of the multiplex marker system in a segregating population.

  20. Marker-aided Incorporation of Xa38, a Novel Bacterial Blight Resistance Gene, in PB1121 and Comparison of its Resistance Spectrum with xa13 + Xa21.

    Science.gov (United States)

    Ellur, Ranjith K; Khanna, Apurva; S, Gopala Krishnan; Bhowmick, Prolay K; Vinod, K K; Nagarajan, M; Mondal, Kalyan K; Singh, Nagendra K; Singh, Kuldeep; Prabhu, Kumble Vinod; Singh, Ashok K

    2016-01-01

    Basmati rice is preferred internationally because of its appealing taste, mouth feel and aroma. Pusa Basmati 1121 (PB1121) is a widely grown variety known for its excellent grain and cooking quality in the international and domestic market. It contributes approximately USD 3 billion to India's forex earning annually by being the most traded variety. However, PB1121 is highly susceptible to bacterial blight (BB) disease. A novel BB resistance gene Xa38 was incorporated in PB1121 from donor parent PR114-Xa38 using a modified marker-assisted backcross breeding (MABB) scheme. Phenotypic selection prior to background selection was instrumental in identifying the novel recombinants with maximum recovery of recurrent parent phenome. The strategy was effective in delimiting the linkage drag to <0.5 mb upstream and <1.9 mb downstream of Xa38 with recurrent parent genome recovery upto 96.9% in the developed NILs. The NILs of PB1121 carrying Xa38 were compared with PB1121 NILs carrying xa13 + Xa21 (developed earlier in our lab) for their resistance to BB. Both NILs showed resistance against the Xoo races 1, 2, 3 and 6. Additionally, Xa38 also resisted Xoo race 5 to which xa13 + Xa21 was susceptible. The PB1121 NILs carrying Xa38 gene will provide effective control of BB in the Basmati growing region. PMID:27403778

  1. Studies on fire blight.

    NARCIS (Netherlands)

    Schouten, H.J.

    1991-01-01

    Part 1Effects of water potential and temperature on multiplication of and pressure by Erwinia amylovora in host plantsAnalysis of field data from Eve Billing, England, on the duration of the incubation period of fire blight revealed that temperature and rainfall wer

  2. Rootstock-regulated gene expression patterns associated with fire blight resistance in apple

    Science.gov (United States)

    Background: Desirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple....

  3. Bacterial succession on decomposing leaf litter exhibits a specific occurrence pattern of cellulolytic taxa and potential decomposers of fungal mycelia.

    Science.gov (United States)

    Tláskal, Vojtěch; Voříšková, Jana; Baldrian, Petr

    2016-11-01

    The decomposition of dead plant biomass contributes to the carbon cycle and is one of the key processes in temperate forests. While fungi in litter decomposition drive the chemical changes occurring in litter, the bacterial community appears to be important as well, especially later in the decomposition process when its abundance increases. In this paper, we describe the bacterial community composition in live Quercus petraea leaves and during the subsequent two years of litter decomposition. Members of the classes Alpha-, Beta- and Gammaproteobacteria and the phyla Actinobacteria, Bacteroidetes and Acidobacteria were dominant throughout the experiment. Bacteria present in the oak phyllosphere were rapidly replaced by other taxa after leaf senescence. There were dynamic successive changes in community composition, in which the early-stage (months 2-4), mid-stage (months 6-8) and late-stage (months 10-24) decomposer communities could be distinguished, and the diversity increased with time. Bacteria associated with dead fungal mycelium were important during initial decomposition, with sequence relative abundances of up to 40% of the total bacterial community in months 2 and 4 when the highest fungal biomass was observed. Cellulose-decomposing bacteria were less frequent, with abundance ranging from 4% to 15%. The bacterial community dynamics reflects changes in the availability of possible resources either of the plant or microbial origin. PMID:27543318

  4. Assessment of Relationship Between Bacterial Stripe Resistance And Leaf Protein Bands In Rice (Oryza sativa L.) Varieties.

    Science.gov (United States)

    Talei, D.; Fotokian, M. H.

    2008-01-01

    Bacterial stripe as a new rice disease in Iran is more frequent nowadays. The objective of this study was to assessment of resistance in rice varieties together with evaluating of zymogram bands resulted from SDS PAGE electrophoresis of leaf proteins. For this purpose, 30 lines were tested in a randomized complete block design with three replications. The analysis of variance showed that there was significant difference between genotypes for resistance. Mean compare based on field results revealed that Domsiyah had the lowest resistance while Nemat and 7162 demonstrated the highest resistance. Laboratory results showed that there were significant difference between protein bands resulted from sensitive and resistance verities. Twenty bands were observed through SDS PAGE electrophoresis of leaf proteins. The 9th and 12th bands were found in sensitive varieties while were not in resistance genotypes. According to the results of this study, 7162 variety can be considered as the sources of resistance in breeding programs. Meanwhile attending to existence of 9th and 12th bands in sensitive varieties, resistance against bacterial stripe of rice maybe influenced by absence of these proteins.

  5. Variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps biosynthetic locus in Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice

    Directory of Open Access Journals (Sweden)

    Sonti Ramesh V

    2004-10-01

    Full Text Available Abstract Background In animal pathogenic bacteria, horizontal gene transfer events (HGT have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (LPS. As a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. Since LPS is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. Although LPS has been suggested as a potentiator of plant defense responses, interstrain variation at lps biosynthetic gene clusters has not been reported for any plant pathogenic bacterium. Results We report here the complete sequence of a 12.2 kb virulence locus of Xanthomonas oryzae pv. oryzae (Xoo encoding six genes whose products are homologous to functions involved in LPS biosynthesis and transport. All six open reading frames (ORFs have atypical G+C content and altered codon usage, which are the hallmarks of genomic islands that are acquired by horizontal gene transfer. The lps locus is flanked by highly conserved genes, metB and etfA, respectively encoding cystathionine gamma lyase and electron transport flavoprotein. Interestingly, two different sets of lps genes are present at this locus in the plant pathogens, Xanthomonas campestris pv. campestris (Xcc and Xanthomonas axonopodis pv. citri (Xac. The genomic island is present in a number of Xoo strains from India and other Asian countries but is not present in two strains, one from India (BXO8 and another from Nepal (Nepal624 as well as the closely related rice pathogen, Xanthomonas oryzae pv. oryzicola (Xoor. TAIL-PCR analysis indicates that sequences related to Xac are present at the lps locus in both BXO8 and Nepal624. The Xoor strain has a hybrid lps gene cluster, with sequences at the metB and etfA ends, being most closely related to sequences from Xac and the tomato pathogen, Pseudomonas syringae pv. tomato respectively. Conclusion This is the first report of hypervariation at an lps locus between different strains of a plant pathogenic bacterium. Our results indicate that multiple HGT events have occurred at this locus in the xanthomonad group of plant pathogens.

  6. 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.

  7. Differential survival of solitary and aggregated bacterial cells promotes aggregate formation on leaf surfaces

    Science.gov (United States)

    Monier, J.-M.; Lindow, S. E.

    2003-01-01

    The survival of individual Pseudomonas syringae cells was determined on bean leaf surfaces maintained under humid conditions or periodically exposed to desiccation stress. Cells of P. syringae strain B728a harboring a GFP marker gene were visualized by epifluorescence microscopy, either directly in situ or after recovery from leaves, and dead cells were identified as those that were stained with propidium iodide in such populations. Under moist, conducive conditions on plants, the proportion of total live cells was always high, irrespective of their aggregated state. In contrast, the proportion of the total cells that remained alive on leaves that were periodically exposed to desiccation stress decreased through time and was only ≈15% after 5 days. However, the fraction of cells in large aggregates that were alive on such plants in both condition was much higher than more solitary cells. Immediately after inoculation, cells were randomly distributed over the leaf surface and no aggregates were observed. However, a very aggregated pattern of colonization was apparent within 7 days, and >90% of the living cells were located in aggregates of 100 cells or more. Our results strongly suggest that, although conducive conditions favor aggregate formation, such cells are much more capable of tolerating environmental stresses, and the preferential survival of cells in aggregates promotes a highly clustered spatial distribution of bacteria on leaf surfaces. PMID:14665692

  8. Expression Profiling of Genes Related to Adult Plant Resistance to Bacterial Blight of Rice%水稻白叶枯病成株抗性相关基因的表达谱

    Institute of Scientific and Technical Information of China (English)

    沙爱华; 林兴华; 黄俊斌; 张端品

    2006-01-01

    Genes related to adult plant resistance (APR) of rice to Xanthomonas oryzae pv. oryzae were detected by using cDNA-AFLP (amplified fragment length polymorphism). Of 16 000 fragments inspected, 122 showed differential expression patterns. 70 fragments were cloned and sequenced. 41 fragments had amino acid sequences homologous to known proteins. Northern blots and RT-PCR analysis were used to test the expression of 29 fragments which encoded proteins with identified function and of these, 10 fragments were verified to be associated with APR. These fragments encode proteins involved in electron transfer and proton transport, the ubiquitin-proteasome pathway, and epigenetic gene regulation. Differential expression of these fragments between seedlings and adult plants suggests that they may play a pivotal role in rice APR to bacterial blight.%采用cDNA-AFLP(amplified fragment length polymorphism)分析了水稻白叶枯病成株抗性相关基因的表达.在检测的16 000个基因片段中,122个表现为差异表达.对其中的70个片段进行了克隆和测序,有41个片段编码的氨基酸序列与已知基因同源.通过Northern杂交和RT-PCR分析了29个功能已知基因的表达,检测到10个基因表现出表达差异.这些基因编码蛋白参与电子和质子转运、泛素-蛋白体途径以及表观遗传调控(epigenetic regulation)等.这些基因在不同处理的水稻苗期和成株期叶片中存在表达差异,表明它们可能在成株抗性中发挥重要作用.

  9. 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.

  10. 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)。

  11. Biological Control of Pseudomonas syringae pv. syringae, the Causal Agent of Basal Kernel Blight of Barley, by Antagonistic Pantoea agglomerans.

    Science.gov (United States)

    Braun-Kiewnick, A; Jacobsen, B J; Sands, D C

    2000-04-01

    ABSTRACT Strains of Pantoea agglomerans (synanamorph Erwinia herbicola) suppressed the development of basal kernel blight of barley, caused by Pseudomonas syringae pv. syringae, when applied to heads prior to the Pseudomonas syringae pv. syringae infection window at the soft dough stage of kernel development. Field experiments in 1994 and 1995 revealed 45 to 74% kernel blight disease reduction, whereas glasshouse studies resulted in 50 to 100% disease control depending on the isolate used and barley cultivar screened. The efficacy of biocontrol strains was affected by time and rate of application. Percentage of kernels infected decreased significantly when P. agglomerans was applied before pathogen inoculation, but not when coinoculated. A single P. agglomerans application 3 days prior to the pathogen inoculation was sufficient to provide control since populations of about 10(7) CFU per kernel were established consistently, while Pseudomonas syringae pv. syringae populations dropped 100-fold to 2.0 x 10(4) CFU per kernel. An application to the flag leaf at EC 49 (before heading) also reduced kernel infection percentages significantly. Basal blight decreased with increasing concentrations (10(3) to 10(7) CFU/ml) of P. agglomerans, with 10(7) CFU/ml providing the best control. For long-term preservation and marketability, the survival of bacterial antagonists in several wettable powder formulations was tested. Over all formulations tested, the survival declined between 10- to >100-fold over a period of 1.5 years (r = -0.7; P = 0.000). Although not significant, storage of most formulations at 4 degrees C was better for viability (90 to 93% survival) than was storage at 22 degrees C (73 to 79%). However, long-term preservation had no adverse effect on biocontrol efficacy. PMID:18944586

  12. Reação de genótipos de feijão ao crestamento bacteriano comum, avaliado por dois métodos de inoculação Reaction of bean genotypes to the common bacterial blight, evaluated by two inoculation methods

    Directory of Open Access Journals (Sweden)

    Alciani da Silva

    2009-01-01

    Full Text Available Conhecer a resistência de genótipos de feijão à fitopatógenos é importante para uso em programas de melhoramento genético. Duas técnicas de inoculação bacteriana foram testadas para avaliar a sensibilidade de genótipos de feijão ao crestamento bacteriano comum, causado por Xanthomonas axonopodis pv. phaseoli. Foram inoculados folíolos de 56 genótipos de feijão, utilizando-se das técnicas de agulhas múltiplas e incisão com tesoura, utilizando o isolado XAP 15497. Foi possível classificar 21 genótipos resistentes, 13 moderadamente resistentes, 9 moderadamente suscetíveis e 13 suscetíveis pelo método de inoculação com agulhas múltiplas. No método de inoculação com tesoura, foi possível classificar 24 genótipos como resistentes, 21 como moderadamente resistentes, 7 como moderadamente suscetíveis e 4 suscetíveis. Os genótipos IPR Chopim, IAPAR 81, IAPAR 16, BRS Campeiro, BRS Radiante, IAPAR 80, UTF 6, SM 9906, PI 2072620, LP 01-51, PB 4, Uirapuru, IAPAR 20, Zonin, IAPAR 31, 2 V, CNPF 7762, BRS Talismã, Pérola, Lon Rosinha e UTF 9 tiveram comportamento semelhante diante dos dois métodos de inoculação. Verificou-se que os dois métodos de inoculação foram eficientes para a determinação das reações de suscetibilidade e resistência dos genótipos. Porém, a técnica de inoculação com agulhas múltiplas demonstrou maior praticidade e precisão para a avaliação da área foliar inoculada.The knowledge of resistance of bean genotypes to pathogens is important to genetic breeding programs. Two methods of bacterial inoculation were tested to evaluate the sensitivity of bean genotypes to common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli. Leaves of 56 bean genotypes were inoculated by the method of multiple needles and the method of incision with scissors, using the isolated XAP 15497. We classified 21 genotypes as resistant, 13 as moderately resistant, 9 as moderately susceptible, and 13 as

  13. Seca dos ponteiros da goiabeira causada por Erwinia psidii: níveis de incidência e aspectos epidemiológicos Guava bacterial blight due to Erwinia psidii: incidence levels and epidemiological aspects

    Directory of Open Access Journals (Sweden)

    Abi Soares Anjos Marques

    2007-01-01

    Full Text Available Um dos fatores limitantes ao cultivo da goiabeira no Brasil é a 'seca dos ponteiros', causada por Erwinia psidii, presente nas regiões Sudeste e Centro-Oeste, onde se concentram grandes áreas produtoras. Considerando a pequena disponibilidade de informações sobre a epidemiologia e níveis de incidência dessa bacteriose, este estudo teve como objetivos: confirmar a distribuição e verificar a dispersão da seca dos ponteiros da goiabeira no Distrito Federal; investigar o efeito da temperatura sobre a multiplicação in vitro de E. psidii; desenvolver um teste de patogenicidade prático e eficiente e avaliar a sobrevivência in vitro da bactéria em diferentes substratos. A doença foi identificada em 56% das propriedades produtoras avaliadas no DF, com 81,9% de correlação entre a presença de sintomas e o diagnóstico laboratorial. A melhor faixa de temperatura para multiplicação de E. psidii foi de 24 a 33 ºC, e a bactéria permaneceu viável por até 120 dias em suspensão em água. A inoculação da bactéria em folhas ou hastes destacadas levou ao aparecimento de sintomas a partir do sétimo dia e mostrou-se eficiente como um teste rápido para se avaliar a patogenicidade de isolados.A major disease that affects guava is 'bacterial blight', caused by Erwinia psidii, which has been reported in Southeastern and Central Regions of Brazil where the major producing areas are located. Considering the lack of information on epidemiology and incidence levels of this disease, the objectives of this study were to confirm the presence and to verify the spread of the disease in Distrito Federal (DF; to determine optimal temperature for in vitro multiplication of E. psidii; to develop a simple and effective method for pathogenicity testing and to evaluate in vitro bacterial survival on different substrates. The disease was detected in 56% of producing orchards evaluated in DF, with a correlation of 81, 9% between presence of symptoms and

  14. Assessing the effect of litter species on the dynamic of bacterial and fungal communities during leaf decomposition in microcosm by molecular techniques.

    Directory of Open Access Journals (Sweden)

    Wenjing Xu

    Full Text Available Although bacteria and fungi are well-known to be decomposers of leaf litter, few studies have examined their compositions and diversities during the decomposition process in tropical stream water. Xishuangbanna is a tropical region preserving one of the highest floristic diversity areas in China. In this study, leaf litter of four dominant plant species in Xishuangbanna was incubated in stream water for 42 days during which samples were taken regularly. Following DNA extraction, PCR-DGGE (denaturing gradient gel electrophoresis and clone-sequencing analyses were performed using bacterial and fungal specific primers. Leaf species have slightly influences on bacterial community rather than fungal community. The richness and diversity of bacteria was higher than that of fungi, which increased towards the end of the 42-day-incubation. The bacterial community was initially more specific upon the type of leaves and gradually became similar at the later stage of decomposition with alpha-proteobacteria as major component. Sequences affiliated to methanotrophs were obtained that indicates potentially occurrence of methane oxidation and methanogenesis. For the fungal community, sequences affiliated to Aspergillus were predominant at the beginning and then shifted to Pleosporales. Our results suggest that the microorganisms colonizing leaf biofilm in tropical stream water were mostly generalists that could exploit the resources of leaves of various species equally well.

  15. 土层置换对马铃薯叶片酶活性及晚疫病的影响%Effects of Soil Replacement of Potato Leaf Enzyme Activity and Late Blight Disease Index

    Institute of Scientific and Technical Information of China (English)

    张丁; 苍真名; 白雪静; 王秋菊; 刘峰; 高中超; 焦峰; 翟瑞常

    2015-01-01

    The analysis of the effects of soil displacement and soil sterilization measures on enzyme activity in leaves of potato, and provide the technical support of sciencefor the elimination of potato continuous cropping obstacle was reaseached. The results showed that soil replacement or soil sterilization treatment increased the activity of protective enzyme in potato leaves (superoxide dismutase, peroxidase and catalase), and reduced the activity of cellulase and protease, which improved the resistance of potato to late blight. Soil replacement and soil sterilization treatment eliminates the potato late blight caused by continuous cropping obstacles incidence,and Phasphate 15% and the replacement of soil (T2) and Application of soil fungicide antiseptic spirit and no replacement of soil (H) treatment in eliminating due to continuous cropping potato late blightbest effect. But the soil through?soil replacement and add organic fertilizer after treatment (T3 treatment), the disease index of potato late blight of potato during the growing period of the whole inner were significantly higher than the other four treatments,and the replacement of soil (T1),T2 and H treatment was 17.5%,47.1%,60.8% and 66.6% higher than the CK in 77 days respectively,which showed that the use of organic manure was not conducive to the reduction of potato late blight in soil after replacement.%研究了土层置换及土壤灭菌措施对马铃薯叶片酶活性的影响. 结果表明,土层置换或土壤灭菌处理提高了马铃薯叶片中保护酶(超氧化物歧化酶、过氧化物酶和过氧化氢酶)的活性,降低了叶片中纤维素酶和蛋白酶的活性,提高了马铃薯对晚疫病的抵抗能力. 土层置换和土壤灭菌处理可以消除马铃薯由于连作障碍而产生的晚疫病的发病率,其中增施磷肥15%且置换土壤(T2)与施杀菌灵且不置换土壤(H)处理在消除马铃薯由于连作而产生的晚疫病方面效果最佳. 而土壤经过土壤

  16. 五味子叶枯病病原菌的生物学特性及其拮抗放线菌的初筛∗%Biological Characteristics of the Pathogen of Schisandra chinensis Leaf Blight and Screening of Antagonistic Actinomycete Strain against the Pathogen

    Institute of Scientific and Technical Information of China (English)

    王壮; 张爱华; 雷锋杰; 匙坤; 张连学

    2015-01-01

    采用室内平皿培养法研究五味子叶枯病菌的生物学特性,平板对峙法筛选拮抗放线菌。结果表明:叶枯病病原菌在PDA及PDBA培养基上最有利于菌丝生长及产孢;温度对菌丝生长和产孢量影响较大,25℃为其最适温度,同样温度下,黑暗条件显著有利于产生孢子,光照更利于菌丝生长;pH 6~7为菌株生长最适pH;最佳碳、氮源分别为果糖及蛋白胨;孢子致死温度测定为54℃。筛选到2株对五味子叶枯病病原菌拮抗效果较好的放线菌A-25-8和A38,其拮抗率分别为66�26%和66�10%。%Petri dish culture method was used to study biological characteristics of Schisandra chinensis leaf blight pathogen, and plate confrontation method was used to screen antagonistic actino⁃mycetes. The results showed that mycelia grew faster and spore generated more in medium PDA and PDBA. Temperature affected mycelia growth and spore generation at 25 ℃. At the same tempera⁃ture, dark condition was significantly beneficial for spore generation and light condition was benefi⁃cial for mycelial growth. pH 6~7 was most suitable for the pathogen. Fructose and peptone were the best carbon source and nitrogen source for the pathogen. Deadly temperature for the spore was 54 ℃. Two strains ( A-25-8 and A38 ) of the 28 actinomycetes had potential antagonistic effects against leaf blight pathogen and inhibition rate was 66�26% and 66�10%, respectively.

  17. Late Blight demonstrations December 2013-February 2014

    NARCIS (Netherlands)

    Schepers, H.T.A.M.; Gunadi, N.; Putter, de H.; Wustman, R.; Moekasan, T.K.; Laksminiwati, P.; Karjadi, A.K.

    2014-01-01

    Late blight caused by Phytophthora infestans is one of the most important diseases worldwide. Also in Indonesia control of late blight is very important in potato and tomato, especially in the rainy season. In order to learn more about the important factors that determine late blight control - such

  18. Disease-reducing effect of Chromolaena odorata extract on sheath blight and other rice diseases.

    Science.gov (United States)

    Khoa, Nguyen Đac; Thuy, Phan Thi Hong; Thuy, Tran Thi Thu; Collinge, David B; Jørgensen, Hans Jørgen Lyngs

    2011-02-01

    Sheath blight caused by Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a major cause of crop loss in intensive rice production systems. No economically viable control methods have been developed. We screened aqueous extracts of common herbal plants that could reduce sheath blight lesions and found that foliar spraying and seed soaking application of extracts of either fresh or dried leaves of Chromolaena odorata gave up to 68% reduction in sheath blight lesion lengths under controlled and semi-field conditions. The observed reductions were not dependent on growth conditions of C. odorata and rice cultivar. The effect was observed until 21 days after inoculation and was not dependent on microbial activity. Under semi-field conditions, extracts also reduced severity of other important rice diseases, i.e., blast (Pyricularia oryzae) using foliar spray (up to 45%), brown spot (Bipolaris oryzae) using seed treatment (up to 57%), and bacterial blight (Xanthomonas oryzae pv. oryzae) using both application methods (up to 50%). PMID:20839964

  19. 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.

  20. Use of Promising Bacterial Strains for Controlling Anthracnose on Leaf and Fruit of Mango Caused by Colletotrichum gloeosporioides

    Directory of Open Access Journals (Sweden)

    Prakong YENJIT

    2004-06-01

    Full Text Available A total 146 isolates of bacteria were taken from leaf surface, fruit skin, and blossom of mango (var. Nam Dorkmai. They were tested for the inhibition of mycelial growth of Colletotrichum gloeosporioides, a causal agent of anthracnose, on potato dextrose agar (PDA. Seventy-four bacterial isolates inhibited the growth of fungal mycelia by 24.51-49.10%. The 40 highly effective isolates out of 74 isolates were further tested for the potential to reduce the development of anthracnose lesion on detached leaves of mango marcotages at 24 h after inoculation of pathogen. Results indicated that 12 isolates provided high efficacy for inhibiting disease by 51.39-86.11%. Application of these bacteria on mango fruits at 24 h prior to the inoculation of the pathogen revealed that isolates B46 and B12 suppressed disease by 50.36 and 44.13% respectively while Trichoderma harzianum CB-Pin-01 provided 37.30% of the inhibition. For controlling post-harvest disease, an isolate B12 or B12 integrated with hot water treatment (55 oC provided 91.33 and 88.00% of disease severity reduction respectively when applied at 24 h before inoculation of pathogen. Isolates B12 and B44 were identified as Bacillus subtilis while B46 and K112 were B. licheniformis and B. cereus respectively. The mechanism of these isolates for controlling C. gloeosporioides was the reduction of spore germination and the inhibition of germ-tube elongation.

  1. Linhagens de feijoeiro comum com fenótipos agronômicos favoráveis e resistência ao crestamento bacteriano comum e antracnose Common bean lines with suitable agronomic phenotypes and resistant to bacterial blight and anthracnose

    Directory of Open Access Journals (Sweden)

    Joaquim Geraldo Cáprio da Costa

    2003-10-01

    Full Text Available O crestamento bacteriano comum e a antracnoseincitados por Xanthomonas axonopodis pv. phaseoli (Smith Vauterin, Hoste, Kesters & Swings e Colletotrichum lindemuthianum (Sacc. & Magn. Scrib., respectivamente, podem reduzir consideravelmente a produtividade do feijoeiro comum (Phaseolus vulgaris L.. Conduziu-se este trabalho com o objetivo de obter linhagens com resistência conjunta ao crestamento bacteriano comum e à antracnose, com características agronômicas desejáveis. Foram obtidas 35 populações F2 provenientes de cruzamentos simples entre linhagens com resistência ao crestamento bacteriano comum proveniente de P. acutifolius A. Gray e linhagens resistentes à antracnose e com características agronômicas favoráveis. As populações segregantes de F2 a F5 foram inoculadas com o patótipo 89 de C. lindemuthianum com uma concentração de 1,2 x 10(6 conídios/mL e submetidas à seleção massal modificada. As plantas que apresentaram grau superior a 4 foram eliminadas. Na geração F5, foi realizada seleção individual das plantas remanescentes para obter as famílias F6. As famílias F6 foram avaliadas mediante inoculação com os patótipos 55, 89, 95 e 453 de C. lindemuthianum. As famílias F7 resistentes à antracnose foram inoculadas em casa-de-vegetação por incisão das folhas primárias com tesoura mergulhada em uma suspensão de 5 x 10(7 ufc do isolado XpCNF 15 de X. axonopodis pv. phaseoli. As linhagens resistentes foram avaliadas em quatro experimentos de campo. Foram selecionadas 17 linhagens com alto rendimento de grãos, resistentes ao crestamento bacteriano comum e à antracnose, com boa altura de inserção das vagens inferiores e resistentes ao acamamento.Common bacterial blight and anthracnose diseases, incited by Xanthomonas axonopodis pv. phaseoli (Smith Vauterin, Hoste, Kesters & Swings and Colletotrichum lindemuthianum (Sacc. & Magn. Scrib., respectively, are major constrains for dry bean (Phaseolus vulgaris L

  2. 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.

  3. Appraise a combination of fungicides against blast and sheath blight diseases of paddy (Oryza sativa L.)

    OpenAIRE

    Prasanna Kumar M K; Veerabhadraswamy A L

    2014-01-01

    In present study various fungicides were screened against blast (leaf and neck) and sheath blight disease of rice. Among them, Conika 50% WP (Kasugamycin 5% + Copper Oxychloride 45% WP), Dhanucop Team (Tricyclazole 75% WP) and RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG) were found effective against blast diseases. While, the seed treatment fungicide Isotianil SC 200 and its combination with Trifloxystrobin 500 SC were found least effective against leaf and neck bla...

  4. 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.

  5. Erwinia amylovora pyrC mutant causes fire blight despite pyrimidine auxotrophy.

    Science.gov (United States)

    Ramos, L S; Sinn, J P; Lehman, B L; Pfeufer, E E; Peter, K A; McNellis, T W

    2015-06-01

    Erwinia amylovora bacteria cause fire blight disease, which affects apple and pear production worldwide. The Erw. amylovora pyrC gene encodes a predicted dihydroorotase enzyme involved in pyrimidine biosynthesis. Here, we discovered that the Erw. amylovora pyrC244::Tn5 mutant was a uracil auxotroph. Unexpectedly, the Erw. amylovora pyrC244::Tn5 mutant grew as well as the wild-type in detached immature apple and pear fruits. Fire blight symptoms caused by the pyrC244::Tn5 mutant in immature apple and pear fruits were attenuated compared to those caused by the wild-type. The pyrC244::Tn5 mutant also caused severe fire blight symptoms in apple tree shoots. A plasmid-borne copy of the wild-type pyrC gene restored prototrophy and symptom induction in apple and pear fruit to the pyrC244::Tn5 mutant. These results suggest that Erw. amylovora can obtain sufficient pyrimidine from the host to support bacterial growth and fire blight disease development, although de novo pyrimidine synthesis by Erw. amylovora is required for full symptom development in fruits. Significance and impact of the study: This study provides information about the fire blight host-pathogen interaction. Although the Erwinia amylovora pyrC mutant was strictly auxotrophic for pyrimidine, it grew as well as the wild-type in immature pear and apple fruits and caused severe fire blight disease in apple trees. This suggests that Erw. amylovora can obtain sufficient pyrimidines from host tissue to support growth and fire blight disease development. This situation contrasts with findings in some human bacterial pathogens, which require de novo pyrimidine synthesis for growth in host blood, for example.

  6. Late blight and early blight resistance from Solanum hougasii introgressed into Solanum tuberosum

    Science.gov (United States)

    Late blight, caused by Phytophthora infestans, and early blight, incited by Alternaria solani,are the two most widely occurring foliar diseases of potato in the U.S. Resistance to both diseases is necessary if growers are to reduce fungicide applications. Field resistance to late blight has previous...

  7. Complete Genome Sequence for the Fusarium Head Blight Antagonist Bacillus amyloliquefaciens Strain TrigoCor 1448

    OpenAIRE

    Nelson, Beth A.; Ramaiya, Preethi; Lopez de Leon, Alfredo; Kumar, Ravi; Crinklaw, Austin; Jolkovsky, Eliana; Crane, Julia M.; Bergstrom, Gary C; Rey, Michael W.

    2014-01-01

    We present the complete genome sequence for Bacillus amyloliquefaciens TrigoCor 1448 (ATCC 202152), a bacterial biological control agent for Fusarium head blight in wheat. We compare it to its closest relative, B. amyloliquefaciens strain AS43.3.

  8. Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight

    Science.gov (United States)

    Microencapsulation and controlled release of Pantoea agglomerans strain E325 (E325), which is an antagonist to bacterial pathogen (Erwinia amylovora) of fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 µm in diamet...

  9. 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.

  10. Biocontrol of Late Blight (Phytophthora capsici Disease and Growth Promotion of Pepper by Burkholderia cepacia MPC-7

    Directory of Open Access Journals (Sweden)

    Mao Sopheareth

    2013-03-01

    Full Text Available A chitinolytic bacterial strain having strong antifungal activity was isolated and identified as Burkholderia cepacia MPC-7 based on 16S rRNA gene analysis. MPC-7 solubilized insoluble phosphorous in hydroxyapatite agar media. It produced gluconic acid and 2-ketogluconic acid related to the decrease in pH of broth culture. The antagonist produced benzoic acid (BA and phenylacetic acid (PA. The authentic compounds, BA and PA, showed a broad spectrum of antimicrobial activity against yeast, several bacterial and fungal pathogens in vitro. To demonstrate the biocontrol efficiency of MPC-7 on late blight disease caused by Phytophthora capsici, pepper plants in pot trials were treated with modified medium only (M, M plus zoospore inoculation (MP, MPC-7 cultured broth (B and B plus zoospore inoculation (BP. With the sudden increase in root mortality, plants in MP wilted as early as five days after pathogen inoculation. However, plant in BP did not show any symptom of wilting until five days. Root mortality in BP was markedly reduced for as much as 50%. Plants in B had higher dry weight, P concentration in root, and larger leaf area compared to those in M and MP. These results suggested that B. cepacia MPC-7 should be considered as a candidate for the biological fertilizer as well as antimicrobial agent for pepper plants.

  11. Antibiosis Contributes to Biological Control of Fire Blight by Pantoea agglomerans Strain Eh252 in Orchards.

    Science.gov (United States)

    Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

    2002-11-01

    ABSTRACT Fire blight, caused by Erwinia amylovora, is the most serious bacterial disease of pear and apple trees. Biological control with strains of Pantoea agglomerans (syn. Erwinia herbicola) may provide an effective disease management strategy for fire blight. Most strains of P. agglomerans evaluated for suppression of fire blight produce compounds that inhibit the growth of E. amylovora in culture. The role of these inhibitory compounds in fire blight suppression in orchard environments has not been studied. In seven field trials in Oregon, we compared the population dynamics and disease suppression with P. agglomerans Eh252, a strain that produces a single antibiotic, with its near-isogenic antibiotic-deficient derivative, strain 10:12. Water or suspensions of Eh252 or 10:12 (1 x 10(8) CFU/ml) were applied at 30 and 70% bloom to pear or apple trees. Aqueous suspensions of freeze-dried cells of E. amylovora (3 x 10(5) CFU/ml) were applied at full bloom. Additional trees were treated with streptomycin or oxytetracycline at 30 and 70% bloom and in some experiments, 1 day after application of the pathogen. Population sizes of Eh252 or 10:12 on pear blossoms were estimated by spreading dilutions of blossom washes on culture media. Average population sizes of Eh252 and 10:12 on blossoms ranged from 10(5) to 10(7) CFU, and in five of six trials, the relative area under the population curve of Eh252 was not significantly different than that of its derivative 10:12. Both Eh252 and 10:12 reduced the growth of the pathogen on blossoms compared with inoculated water-treated controls. Eh252 significantly decreased the incidence of fire blight in six of seven field trials compared with the incidence on water-treated trees, and 10:12 similarly reduced the incidence of fire blight in four of seven trials. In three of seven field trials, trees treated with Eh252 had a significantly lower incidence of fire blight compared with trees treated 3 with 10:12. Overall,3 Eh252 reduced

  12. 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. PMID:26654914

  13. Mycosphaerella and Teratosphaeria species associated with leaf diseases on Eucalyptus globulus in southern Brazil

    NARCIS (Netherlands)

    Teodoro, M.G.; Ferreira, M.A.; Guimarães, L.M.S.; Mafia, R.G.; Groenewald, J.Z.; Crous, P.W.; Alfenas, A.C.

    2012-01-01

    Leaf blight and defoliation caused by Teratosphaeria species is one of the most important leaf diseases of Eucalyptus globulus. Due to the importance of this tree species for the production of pulp and paper, and recent reports of severe leaf disease symptoms in Brazil, the present study was conduct

  14. Appraise a combination of fungicides against blast and sheath blight diseases of paddy (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar M K

    2014-02-01

    Full Text Available In present study various fungicides were screened against blast (leaf and neck and sheath blight disease of rice. Among them, Conika 50% WP (Kasugamycin 5% + Copper Oxychloride 45% WP, Dhanucop Team (Tricyclazole 75% WP and RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG were found effective against blast diseases. While, the seed treatment fungicide Isotianil SC 200 and its combination with Trifloxystrobin 500 SC were found least effective against leaf and neck blast diseases. However, in case of sheath blight, Thifluzamide 24% SC, RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG, Propiconazole 25% EC (Tilt, Tricyclazole 75% WP (Beam and a new combination fungicide, Fluxapyroxad 62.5 g/l + Epoxiconazlle 62.5 g/l EC (Adexar w/v EC were found effective.

  15. Compatibilidade de Dicyma pulvinata com defensivos agrícolas e eficiência do biocontrole do mal-das-folhas da seringueira em campo Compatibility of Dicyma pulvinata with pesticides and biocontrol efficiency of South American leaf blight of rubber tree under field conditions

    Directory of Open Access Journals (Sweden)

    Débora Ferreira Melo

    2008-02-01

    Full Text Available O objetivo deste trabalho foi avaliar quatro isolados do fungo antagonista Dicyma pulvinata quanto à compatibilidade com defensivos agrícolas e adjuvantes, e a eficiência desses isolados no controle do mal-das-folhas (Microcyclus ulei da seringueira (Hevea sp. em campo. A compatibilidade dos isolados com defensivos e adjuvantes foi avaliada com base no crescimento micelial e na esporulação do fungo, em testes conduzidos in vitro. Para avaliação da eficiência do antagonista contra M. ulei, em campo, os quatros isolados do antagonista foram comparados ao controle exercido pelo tratamento com os fungicidas propiconazol + mancozeb. Os ensaios conduzidos em laboratório indicaram a incompatibilidade de D. pulvinata com os fungicidas benomyl, carbendazim, mancozeb, propiconazol e, ainda, com o inseticida acaricida endosulfan. Dois dos adjuvantes testados (Tween 20 e Tween 80 não afetaram o desenvolvimento do fungo. Foi comprovada a ação do antagonista D. pulvinata sobre M. ulei, em campo, com destaque para os isolados CEN 62 e CEN 93, que apresentaram eficiência de controle semelhante ao tratamento fungicida padrão.The objective of this work was to evaluate four isolates of the antagonist fungus Dicyma pulvinata in terms of its compatibility with chemical pesticides and adjuvants products, and the efficiency of these isolates as biocontrol agent against South American leaf blight (Microcyclus ulei of rubber tree (Hevea sp. under field conditions. Isolates compatibility with chemical pesticides and adjuvants was evaluated on mycelial growth and fungus sporulation in vitro. To assess the efficiency of the antagonist against M. ulei under field conditions, the four isolates were compared to the control by the fungicide mixture propiconazol + mancozeb. The assays showed incompatibility of the antagonistic fungus with the fungicides benomyl, carbendazim, mancozeb, propiconazol, besides the insecticide-acaricide endosulfan. Two of the adjuvants

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

    OpenAIRE

    A. A. Yamin; A. Sudarman; D. Evvyernie

    2013-01-01

    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 be...

  17. 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....... 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...

  18. Novel species of Botryosphaeriaceae associated with shoot blight of pistachio.

    Science.gov (United States)

    Chen, ShuaiFei; Li, GuoQing; Liu, FeiFei; Michailides, Themis J

    2015-01-01

    Various species of phytopathogenic Botryosphaeriaceae were identified previously from pistachio trees worldwide. Disease symptoms caused by pathogens in Botryosphaeriaceae on pistachio include panicle and shoot blight, leaf defoliation, fruit discoloration and decay. In this study species of Botryosphaeriaceae were collected from blighted pistachio shoots in Arizona, USA, and Greece. The aims of this study were to identify these Botryosphaeriaceae isolates and to test their pathogenicity to pistachio. The fungi were identified based on comparisons of DNA sequence data of the nuclear rDNA internal transcribed spacer region (ITS), a partial translation elongation factor 1-alpha gene (TEF1), a partial β-tubulin gene (TUB2) and morphological characteristics. Results indicated that some isolates collected from pistachio represent two previously undescribed species, which we described here as Lasiodiplodia americana sp. nov. from the United States and Neofusicoccum hellenicum sp. nov. from Greece. Field inoculations of L. americana and N. hellenicum on branches of four pistachio cultivars showed that both L. americana and N. hellenicum are pathogenic on pistachio. The four pistachio cultivars differed in their susceptibility to the Botryosphaeriaceae species. Results of this study suggested that the two new species of Botryosphaeriaceae need to be monitored carefully to determine the distribution of these pathogens and the possible spread to other areas.

  19. Novel species of Botryosphaeriaceae associated with shoot blight of pistachio.

    Science.gov (United States)

    Chen, ShuaiFei; Li, GuoQing; Liu, FeiFei; Michailides, Themis J

    2015-01-01

    Various species of phytopathogenic Botryosphaeriaceae were identified previously from pistachio trees worldwide. Disease symptoms caused by pathogens in Botryosphaeriaceae on pistachio include panicle and shoot blight, leaf defoliation, fruit discoloration and decay. In this study species of Botryosphaeriaceae were collected from blighted pistachio shoots in Arizona, USA, and Greece. The aims of this study were to identify these Botryosphaeriaceae isolates and to test their pathogenicity to pistachio. The fungi were identified based on comparisons of DNA sequence data of the nuclear rDNA internal transcribed spacer region (ITS), a partial translation elongation factor 1-alpha gene (TEF1), a partial β-tubulin gene (TUB2) and morphological characteristics. Results indicated that some isolates collected from pistachio represent two previously undescribed species, which we described here as Lasiodiplodia americana sp. nov. from the United States and Neofusicoccum hellenicum sp. nov. from Greece. Field inoculations of L. americana and N. hellenicum on branches of four pistachio cultivars showed that both L. americana and N. hellenicum are pathogenic on pistachio. The four pistachio cultivars differed in their susceptibility to the Botryosphaeriaceae species. Results of this study suggested that the two new species of Botryosphaeriaceae need to be monitored carefully to determine the distribution of these pathogens and the possible spread to other areas. PMID:25977211

  20. 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.

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

    International Nuclear Information System (INIS)

    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. (papers)

  2. Rootstock-regulated gene expression patterns associated with fire blight resistance in apple

    Directory of Open Access Journals (Sweden)

    Jensen Philip J

    2012-01-01

    Full Text Available Abstract Background Desirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple. The purpose of the present study was to quantify rootstock-mediated differences in scion fire blight susceptibility and to identify transcripts in the scion whose expression levels correlated with this response. Results Rootstock influence on scion fire blight resistance was quantified by inoculating three-year old, orchard-grown apple trees, consisting of 'Gala' scions grafted to a range of rootstocks, with E. amylovora. Disease severity was measured by the extent of shoot necrosis over time. 'Gala' scions grafted to G.30 or MM.111 rootstocks showed the lowest rates of necrosis, while 'Gala' on M.27 and B.9 showed the highest rates of necrosis. 'Gala' scions on M.7, S.4 or M.9F56 had intermediate necrosis rates. Using an apple DNA microarray representing 55,230 unique transcripts, gene expression patterns were compared in healthy, un-inoculated, greenhouse-grown 'Gala' scions on the same series of rootstocks. We identified 690 transcripts whose steady-state expression levels correlated with the degree of fire blight susceptibility of the scion/rootstock combinations. Transcripts known to be differentially expressed during E. amylovora infection were disproportionately represented among these transcripts. A second-generation apple microarray representing 26,000 transcripts was developed and was used to test these correlations in an orchard-grown population of trees segregating for fire blight resistance. Of the 690 transcripts originally identified using the first-generation array, 39 had expression levels that correlated with fire blight resistance in the breeding population. Conclusions Rootstocks had significant effects on the fire blight

  3. Determining the order of resistance genes against Stagonospora nodorum blotch, Fusarium head blight and stem rust on wheat chromosome 3BS

    Science.gov (United States)

    Fungal diseases of wheat occur every year in the U.S., leading to significant grain yield losses. Stagonospora nodorum blotch (SNB), Fusarium head blight (FHB) and stem rust (SR) are caused by the fungi Stagonospora nodorum, Fusarium graminearum and Puccinia graminis, respectively. These leaf and he...

  4. Bacteriocin Serratine-P as a biological tool in the control of fire blight Erwinia amylovora.

    Science.gov (United States)

    Schoofs, H; Vandebroek, K; Pierrard, A; Thonart, P; Lepoivre, P; Beaudry, T; Deckers, T

    2002-01-01

    Fire blight, caused by the bacterium Erwinia amylovora (Burill Winslow et al.), is the most important bacterial disease in European pear growing. It can cause a lot of damage in some countries on apple and on pear trees in orchards and also in the fruit tree nurseries. In Belgium, the disease is present since 1972. Control of fire blight in Belgian fruit orchards is made on a broad basis of measurements in and around the fruit trees. The use of an antibiotic is allowed for application only during the primary blossom period under strict controlled regulations. The use of antobiotics in agriculture is strongly discussed on the European level today and will probably disappear in the near future. Therefore, the research on fire blight control concentrates on the possibilities of biological control with antagonistic bacteria such as Pantoea agglomerans (Erwinia herbicola), Bacillus subtilis or Pseudomonas syringae strain A 506. The use of Serratine-P, a phage tail-like bacteriocin, produced by Serratia plymiticum, shows an interesting antibacterial activity against Erwinia amylovora. Its mode of action consists in the perforation of the cytoplasmic membrane of the target cell, inducing perturbations in cellular exchanges and a final lysis of the bacterial cell. In this paper some trials are discussed on the use of Serratine-P at different doses and on different infection types on pear trees. The results indicate interesting protection possibilities on blossom- and fruit infections. PMID:12701444

  5. The early days of late blight

    OpenAIRE

    Birch, Paul RJ; Cooke, David EL

    2013-01-01

    Large-scale DNA sequencing of samples of foliage collected in the 19th century from plants infected with late blight has shown that the potato famines of the 1840s were triggered by a single clonal lineage of Phytophthora infestans, called HERB-1, which persisted for at least 50 years.

  6. In vitro induction of variability through radiation for late blight resistance and heat tolerance in potato

    International Nuclear Information System (INIS)

    In vitro cultured shoots of potato, cvs. 'Kufri Jyoti' and 'Kufri Chandramukhi', were irradiated with 20 and 40 Gy gamma rays. Microtubers, obtained from MIV3 shoots multiplied in vitro, were planted in pots. The resulting plants were screened for resistance to late blight, using detached leaf method. In 'Kufri Chandramukhi', 42% plants and in 'Kufri Jyoti' 36% plants, obtained from 40 Gy treatment, showed resistance to late blight. The frequency of resistant plants was lower from 20 Gy treatment. The progenies of putatively resistant plants were grown in field, and inoculated with sporangial inoculum of late blight fungus. The field grown progeny segregated for disease resistance, and approximately 56% plants showed resistance. During the next propagation, the frequency of resistant plants increased to 72%. For developing heat tolerance, microtubers obtained from 20 and 40 Gy treatments and in vitro multiplied M1V3 shoots were cultured at high temperature of 28C. In both varieties, the number of the microtubers per plant was highly reduced and the resulting microtubers had distorted shape but showed better germination (62%), even in early sowing at relatively higher temperature. Of the two radiation doses, the higher dose of 40 Gy gave better results in both the varieties. Heat tolerance was also assessed from chlorophyll persistence. The progenies from putative heat-tolerant plants were tested in field by planting at higher temperature in two subsequent generations. The heat tolerant plants segregated in each generation, but the frequency of heat-tolerant plants increased. (author)

  7. Prevalence, Development, and Significance of Ascochyta Blight Caused by Peyronellaea pinodes in Pisum elatius Populations Growing in Natural Ecosystems.

    Science.gov (United States)

    Golani, M; Frenkel, O; Bornstein, M; Shulhani, R; Abbo, S; Shtienberg, D

    2016-08-01

    Wild Pisum populations prevail in Israel in regions with diverse climatic conditions. A comprehensive survey was conducted in the winters of 2007-08 and 2008-09 at two sites in northern Israel, aiming to (i) document the density of Pisum elatius plants in natural ecosystems and elucidate factors related to their initial infection by Ascochyta blight and (ii) determine the factors governing disease development over time on individual plants. The surveyors identified P. elatius plants growing in designated quadrats, inspected each plant visually, and recorded the incidence and severity of its Ascochyta blight symptoms. Ascochyta blight, caused by Peyronellaea pinodes, was ubiquitous in Pisum elatius populations at both survey sites in both seasons. However, the total leaf area exhibiting disease symptoms of individual plants was very low, and stem and pod infections were rarely observed. Based on analyses of the survey data, it was suggested that, in natural ecosystems, the teleomorph stage of Peyronellaea pinodes serves as the main source of the primary and the secondary inoculum of the disease. In addition, it was found that infected leaves dropped off soon after infection, thereby precluding development of stem lesions. The plants continued growing and did not die; thus, they overcame the disease and could be considered "cured". This phenomenon was examined and confirmed in artificially inoculated, potted-plant experiments. It would be worthwhile to exploit the potential of this unique resistance mechanism as a tool for Ascochyta blight management in pea breeding. PMID:27050576

  8. Prevalence, Development, and Significance of Ascochyta Blight Caused by Peyronellaea pinodes in Pisum elatius Populations Growing in Natural Ecosystems.

    Science.gov (United States)

    Golani, M; Frenkel, O; Bornstein, M; Shulhani, R; Abbo, S; Shtienberg, D

    2016-08-01

    Wild Pisum populations prevail in Israel in regions with diverse climatic conditions. A comprehensive survey was conducted in the winters of 2007-08 and 2008-09 at two sites in northern Israel, aiming to (i) document the density of Pisum elatius plants in natural ecosystems and elucidate factors related to their initial infection by Ascochyta blight and (ii) determine the factors governing disease development over time on individual plants. The surveyors identified P. elatius plants growing in designated quadrats, inspected each plant visually, and recorded the incidence and severity of its Ascochyta blight symptoms. Ascochyta blight, caused by Peyronellaea pinodes, was ubiquitous in Pisum elatius populations at both survey sites in both seasons. However, the total leaf area exhibiting disease symptoms of individual plants was very low, and stem and pod infections were rarely observed. Based on analyses of the survey data, it was suggested that, in natural ecosystems, the teleomorph stage of Peyronellaea pinodes serves as the main source of the primary and the secondary inoculum of the disease. In addition, it was found that infected leaves dropped off soon after infection, thereby precluding development of stem lesions. The plants continued growing and did not die; thus, they overcame the disease and could be considered "cured". This phenomenon was examined and confirmed in artificially inoculated, potted-plant experiments. It would be worthwhile to exploit the potential of this unique resistance mechanism as a tool for Ascochyta blight management in pea breeding.

  9. Firestop: a chemical against bacterial diseases of fruit trees recently available in Europe

    OpenAIRE

    Brisset, Marie-Noelle; Luisetti, J.; Gaignard, Jean Luc

    1991-01-01

    Effectiveness of Firestop, a slow release formulation of flumequine, was evaluated under controlled conditions (greenhouse, controlled environment chamber) and in experimental orchards, against Erwinia amylovora (fire blight) in pear and apple, and Pseudomonas syringae pv persicae (bacterial dieback) in peach. Firestop (0.3 g ai |-1 for fire blight and 0.1 or 0.15 g ai |- 1 for bacterial dieback) was as efficient as Bordeaux mixture and less efficient than the conventional antibiotics, st...

  10. Gene expression in response to bacterial blight infection in rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@After a comprehensive screening of 47 rice lines inoculat_ed at different development stages with 7 different strains of Xanthomonas oryzae pv. oryzae , we selected 2 strains CR1 and CR7 from CNRRI,China. They gave a resistant and susceptible interaction respectively, when they were used to infect 15 d old seedlings of C101PKT.

  11. Development of late blight resistant potatoes by cisgenic stacking

    NARCIS (Netherlands)

    Jo, K.R.; Kim, C.J.; Kim, S.J.; Kim, T.J.; Bergervoet-van Deelen, J.E.M.; Jongsma, M.A.; Visser, R.G.F.; Jacobsen, E.; Vossen, J.H.

    2014-01-01

    Background Phytophthora infestans, causing late blight in potato, remains one of the most devastating pathogens in potato production and late blight resistance is a top priority in potato breeding. The introduction of multiple resistance (R) genes with different spectra from crossable species into p

  12. Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice.

    Science.gov (United States)

    Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

    2016-06-01

    Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen. PMID:27436950

  13. A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander

    Science.gov (United States)

    A TaqMan-based real-time PCR assay is developed for strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences present only in genomic sequence of oleander strain Ann1. The assay is spe...

  14. Enhanced biological control of phytophthora blight of pepper by biosurfactant-producing pseudomonas.

    Science.gov (United States)

    Ozyilmaz, Umit; Benlioglu, Kemal

    2013-12-01

    Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching (1 × 10(9) cells/ml), ASM (0.1 μg a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil. PMID:25288970

  15. Genetic differences between blight-causing Erwinia species with differing host specificities, identified by suppression subtractive hybridization.

    Science.gov (United States)

    Triplett, Lindsay R; Zhao, Youfu; Sundin, George W

    2006-11-01

    PCR-based subtractive hybridization was used to isolate sequences from Erwinia amylovora strain Ea110, which is pathogenic on apples and pears, that were not present in three closely related strains with differing host specificities: E. amylovora MR1, which is pathogenic only on Rubus spp.; Erwinia pyrifoliae Ep1/96, the causal agent of shoot blight of Asian pears; and Erwinia sp. strain Ejp556, the causal agent of bacterial shoot blight of pear in Japan. In total, six subtractive libraries were constructed and analyzed. Recovered sequences included type III secretion components, hypothetical membrane proteins, and ATP-binding proteins. In addition, we identified an Ea110-specific sequence with homology to a type III secretion apparatus component of the insect endosymbiont Sodalis glossinidius, as well as an Ep1/96-specific sequence with homology to the Yersinia pestis effector protein tyrosine phosphatase YopH.

  16. The Solanum demissumR8 late blight resistance gene is an Sw-5 homologue that has been deployed worldwide in late blight resistant varieties

    NARCIS (Netherlands)

    Vossen, Jack H.; Arkel, van Gert; Bergervoet-van Deelen, Marjan; Jo, Kwang Ryong; Jacobsen, Evert; Visser, Richard G.F.

    2016-01-01

    The potato late blight resistance geneR8has been cloned.R8is found in five late blight resistant varieties deployed in three different continents. R8 recognises Avr8 and is homologous to the NB-LRR protein Sw-5 from tomato.Abstract: The broad spectrum late blight resistance gene R8 from Solanum

  17. Taro Leaf Blight—A Threat to Food Security

    Directory of Open Access Journals (Sweden)

    Tom Okpul

    2012-07-01

    Full Text Available Taro leaf blight (caused by the Oomycete Phytophthora colocasiae is a disease of major importance in many regions of the world where taro is grown. Serious outbreaks of taro leaf blight in Samoa in 1993 and in the last few years in Cameroon, Ghana and Nigeria continue to demonstrate the devastating impact of this disease on the livelihoods and food security of small farmers and rural communities dependent on the crop. The spread of the disease to new geographical areas also poses a major threat to neighbouring countries and taro growing regions still free from the disease. Past research, particularly in the Pacific, has demonstrated that management measures such as chemical and cultural control are largely ineffective and that breeding for disease resistance is the most sustainable approach to manage the disease. Recently, the Pacific and South-east Asian regional taro networks have made excellent progress in developing cultivars resistant to taro leaf blight through enhanced utilization of taro genetic resources and close collaboration between farmers and researchers in breeding programs. These programs have secured vital taro genetic resources for future use. This paper provides an overview of the disease, its origin, distribution, biology, epidemiology, management and global impact. The paper will largely focus on breeding strategies to address the disease including challenges, opportunities and constraints. It also discusses how these breeding experiences and outputs can be scaled up to other geographical areas where the disease has been recently introduced or under threat of introduction.

  18. 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.

  19. Reaction of peach tree genotypes to bacterial leaf spot caused by Xanthomonas arboricola pv. prunis Reação de genótipos de pessegueiro a mancha foliar causada por Xanthomonas arboricola pv. pruni

    Directory of Open Access Journals (Sweden)

    José Gilberto Sousa Medeiros

    2011-02-01

    Full Text Available Bacterial leaf spot (BLS, caused by Xanthomonas arboricola pv. pruni, is one of the most important diseases in Brazilian peach [Prunus persica (L. Batsch] orchards and all over the world. The main objective of this study was to evaluate for BLS sensitivity of peach genotypes. Evaluations of thirty genotypes were carried out during the onset of the disease, for incidence, severity and defoliation, in field conditions. Pearson's correlations between the percentage of defoliation and leaf severity rating were performed. Genotypes 'Conserva 985', 'Conserva 871', 'Conserva 1129', and 'Tropic Snow', as resistance sources, and 'Conserva 1153', 'Bonão', 'Conserva 1125', and 'Atenas', as susceptible to BLS, were submitted to detached-leaf bioassay and greenhouse evaluation. The peach genotypes showed different reactions to the BLS, and none was immune to the pathogen. 'Conserva 985' and 'Conserva 1129' confirmed resistance responsiveness while 'Conserva 1153', 'Conserva 1125' and 'Atenas' were found susceptible for the detached-leaf bioassay.A bacteriose foliar causada por Xanthomonas arboricola pv. pruni é uma das mais importantes doenças do pessegueiro [Prunus persica (L. Batsch] no Brasil e no mundo. Avaliou-se a sensibilidade de genótipos de pessegueiro a X. arboricola pv. pruni. Trinta genótipos foram avaliados em campo, quanto à incidência, severidade e desfolha causada pela bactéria. Calculou-se a correlação entre desfolha e severidade da doença. A partir dos resultados obtidos em campo, foram selecionados quatro genótipos resistentes ('Conserva 985', 'Conserva 871', 'Conserva 1129' e 'Tropic Snow' e quatro suscetíveis ('Conserva 1153', 'Bonão', 'Conserva 1125' e 'Atenas' para serem novamente avaliados pelo bioensáio com folhas destacadas e em casa de vegetação. Os genótipos diferiram quanto a reação ao patógeno, não sendo observada imunidade. Confirmou-se a resistência para 'Conserva 985' e 'Conserva 1129' e a

  20. Hypersensitive response and acyl-homoserine lactone production of the fire blight antagonists Erwinia tasmaniensis and Erwinia billingiae.

    Science.gov (United States)

    Jakovljevic, Vladimir; Jock, Susanne; Du, Zhiqiang; Geider, Klaus

    2008-09-01

    Fire blight caused by the Gram-negative bacterium Erwinia amylovora can be controlled by antagonistic microorganisms. We characterized epiphytic bacteria isolated from healthy apple and pear trees in Australia, named Erwinia tasmaniensis, and the epiphytic bacterium Erwinia billingiae from England for physiological properties, interaction with plants and interference with growth of E. amylovora. They reduced symptom formation by the fire blight pathogen on immature pears and the colonization of apple flowers. In contrast to E. billingiae, E. tasmaniensis strains induced a hypersensitive response in tobacco leaves and synthesized levan in the presence of sucrose. With consensus primers deduced from lsc as well as hrpL, hrcC and hrcR of the hrp region of E. amylovora and of related bacteria, these genes were successfully amplified from E. tasmaniensis DNA and alignment of the encoded proteins to other Erwinia species supported a role for environmental fitness of the epiphytic bacterium. Unlike E. tasmaniensis, the epiphytic bacterium E. billingiae produced an acyl-homoserine lactone for bacterial cell-to-cell communication. Their competition with the growth of E. amylovora may be involved in controlling fire blight.

  1. First Occurence of Fire Blight on Apricot (Prunus armeniaca in Hungary

    Directory of Open Access Journals (Sweden)

    Anita VÉGH

    2013-12-01

    Full Text Available During July 2012, a severe unusual disease symptom was observed on young shoots on apricot (Prunus armeniaca 10/13 hybrid in the city of Pomáz, near Budapest. The naturally infected shoots showed typical symptoms of fire blight including terminal shoots with brown to black necrotic lesions. Symptoms were the same as fire blight symptoms reported from other hosts and locations. The first occurrence of fire blight on an apricot tree in Europe was recorded in Czech Republic in 2011. Samples of the leaves and shoots with symptoms were macerated and spread on King’s medium B. After 24 hours of incubation at 26 °C, bacteria morphologically similar to E. amylovora were detected. Isolate induced hypersensitive reaction on tobacco (Nicotiana tabacum L. ‘White Burley’ leaves. Biochemical test was also used for identification, and the result of API 20E kit (Biomérieux, Marcy l’Etoile, France, demonstrate that the bacterium belongs to Enterobacteriaceae family. A pathogenicity tests were positive on young apricot shoots and immature fruits. For molecular identification of the pathogen the 16S rDNA region was amplified from isolate Ea-ApricotPo1 with a general bacterial primer pair (63f forward and 1389r reverse. The PCR products were cloned into a pGEM T-Easy plasmid vector (Promega, Madison, WI USA and were transformed into Escherichia coli DH5α cells. A recombinant plasmid (2A2.5 was sequenced by M13 forward and reverse primers. The sequence was deposited in GenBank (Accession No. HF546214 and showed 99-100% sequence homology with a number of E. amylovora isolates, including type strain FN666575 with 100% similarity. On the basis of the symptoms, colony morphology, biochemical tests, and 16S rDNA sequence homology, the pathogen was identified as E. amylovora. This is a first record of a natural outbreak of fire blight on apricot in Hungary.

  2. Impact of new populations of Phytophthora infestans on integrated late blight management

    OpenAIRE

    Flier, W. G.; Kessel, G.J.T.; Bosch, van den, F.J.P.; Turkensteen, L.J.

    2002-01-01

    A recent migration of a variable population of P. infestans has largely displaced the clonal A1 population in Western Europe. Sexual reproduction in European late blight populations is now possible and has been reported. The increased levels of aggressiveness form an important epidemiological feature of this new blight population. The impact of `new blight¿ on crop protection strategies based on late blight resistant cultivars and fungicides is discussed

  3. 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

  4. Inheritance and Molecular Mapping of New Genes Conferring Late Blight and CPB Resistance in Mexican Wild Potato Species Solanum pinnatisectum%墨西哥野生马铃薯Solanum pinnatisectum抗晚疫病及抗马铃薯甲虫新基因的遗传分析与分子标记

    Institute of Scientific and Technical Information of China (English)

    陈勤; 孙慧生; 杨继良; 李海燕; Sanjib Nandy; Debbie Beasley; 王冬冬; Mark Goettel

    2009-01-01

    因.同时分离与甲虫抗性密相关的分子标记的工作正在进行中.%Late blight (Phytophthora infestans) and Colorado potato beetle (CPB) are the most disastrous disease and insect problem of potatoes. Development of high levels of late blight and CPB resistant potatoes has become a high priority for the Canadian potato breeding program. New genes for late blight and CPB resistance have been identified in a wild 1EBN diploid Mexican species Solanum pinnatisectum which has been successfully transferred via protoplast fusion to the cultivated potato background. However, development of new potato cultivars with late blight and CPB resistance has been a difficult and cumbersome task. To accelerate the isolation of the resistant genes, molecular DNA markers tightly linked to the resistance are needed. In this study, a susceptible diploid potato S. Cardiophyllum was selected as the male parent to cross with S. Pin-natisectum. The F1 and BC1 populations were assessed for resistance to late blight and CPB by the detached leaf method. Dis-ease test using US-8/A2 mating type isolate revealed that all of the F1 individuals were resistant to the late blight. The ratio of late blight resistant plants to susceptible plants was 1 : 1 in BC1 populations. The results confirmed that a single dominant gene Rpil for late blight resistance was present in S. Pinnatisectum. For CPB resistance, a 1:3 resistant to susceptible ratio in BC1 populations confirmed polygenic inheritance. Molecular marker analysis combined with bulked segregating analysis (BSA) was carried out in the F1 and BC1 populations for fine mapping late blight resistant gene Rpi1 in S. Pinnatisectum. Twenty seven specific PCR primers were designed from sequence information of EST and STS markers located between RFLP markers TG20A and CP56 on potato chromosome Ⅶ. Several new DNA markers showed the linkage relation with the late blight resistant gene Rpi1. The analysis of a large number of individual plants

  5. 水稻内生细菌B196的鉴定及其对水稻纹枯病的防治作用%Identification of Rice Endophytic Bacterial Strain B196 and Its Control Effect on Rice Sheath Blight

    Institute of Scientific and Technical Information of China (English)

    农倩; 陈雪凤; 黎起秦; 袁高庆; 林纬; 黄永禄

    2011-01-01

    从水稻体内分离得到的细菌菌株B196对水稻纹枯病菌Rhizoctonia solani的生长有较强抑制作用.通过形态学和生理生化鉴定及16S rDNA序列分析,将菌株B196鉴定为巨大芽孢杆菌Bacillus megaterium.采用浸种和喷雾的方法将菌株B196接种到水稻植株后,均能在稻株体内回收到该菌株,表明菌株B196能在水稻体内定殖.菌株B196对水稻纹枯病的盆栽和田间防效分别为64.29%和55.13%.%A bacterium strain B196, isolated from the rice plants, could inhibit the growth of Rhizoctonia solani. According to its morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, the strain B196 was identified as Bacillus megaterium. This strain could colonize in rice plants after inoculating with seed dipping and spraying. Control effect of strain B196 on rice sheath blight was 64.29% in pot and 55.13% in fields.

  6. Effect of Morphological Traits on Sheath Blight Resistance in Rice%水稻株形对纹枯病抗性的影响

    Institute of Scientific and Technical Information of China (English)

    韩月澎; 邢永忠; 顾世梁; 陈宗祥; 潘学彪; 陈秀兰

    2003-01-01

    Sheath blight, caused by the Rhizoctonia solani Kuhn, is one of the most serious diseasesof rice (Oryza sativa L.). The relationship between morphological traits and sheath blight resistance wasinvestigated in 1999 and 2000 by using a segregant population consisting of 240 inbred recombinationlines, derived from an elite combination of Zhenshan 97 × Minghui 63. Partial correlation analysis betweenphenotypic data (morphological characteristics and heading date (HD)) and sheath blight ratings (SBR)showed that only one trait, plant compactness, was significantly correlated with resistance to sheath blightin both 1999 and 2000, eight traits, such as plant height, heading date, and penultimate leaf angle, weresignificantly correlated with SBR in either of the two years, and the remaining 10 morphological traits werenot consistently associated with SBR in the two years. A major quantitative trait locus (QTL) controllingplant compactness was found to be in the site on chromosome 9 adjacent to the region responsible forqSB9, a major QTLs conferring sheath blight resistance. One out of the three QTLs contributing to apenultimate leaf angle was mapped approximately on the same region as another sheath blight resistanceQTL, qSB5, located on chromosome 5. Whereas, no QTLs underlying most other traits was detected onthe chromosomal region correlated with sheath blight resistance QTL. The results in the present studysuggested that the morphological traits were not the main factors responsible for the SBR separationamong the recombinant inbred lines (RILs) population. Nevertheless, some morphological characteristicshad some indirect influence on expression of sheath blight resistance genes through altering a microcli-mate on paddy field so as to influence the infection of the pathogen and development of the disease. Anefficient approach in resistance breeding to sheath blight was recommended by pyramiding major QTLs forsheath blight resistance and selecting those morphological

  7. Fusarium head blight of winter rye (Secale cereale L.

    Directory of Open Access Journals (Sweden)

    Irena Kiecana

    2012-12-01

    Full Text Available Investigations on Fusarium head blight of rye were carried out in the years 2005-2007 on 10 production fields in the Lublin region. The percentage of heads showing the fusariosis symptoms in the years 2005-2007 ranged from 0 to 7%. Mycological analysis of kernels and chaff obtained from heads with Fusarium blight (scab symptoms showed that Fusarium avenaceum, Fusarium culmorum and Fusarium sporotrichioides were the largest threat to heads of this cereal. The species of Fusarium poae and Fusarium crookwellense were also isolated from infected rye heads. The dominance of particular species in infecting rye heads was determined by weather conditions.

  8. Systems and models of fire blight (Erwinia amylovora prediction

    Directory of Open Access Journals (Sweden)

    Krzysztof Kielak

    2013-12-01

    Full Text Available The paper presents fire blight prediction models and systems, developed in Europe (system Billing - versions: BOS, BRS, BIS95 and originated from this system: Firescreen, FEUERBRA and ANLAFBRA and in United States (Californian system, model Maryblyt and system Cougarblight. Use of above models and systems in various climatic-geographic conditions and comparison of obtained prognostic data to real fire blight occurrence is reviewed. The newest trends in research on improvement of prognostic analyses parameters with their adjustment to particular conditions and consideration of infection source occurrence are also presented.

  9. Drag increase and drag reduction found in phytoplankton and bacterial cultures in laminar flow: Are cell surfaces and EPS producing rheological thickening and a Lotus-leaf Effect?

    Science.gov (United States)

    Jenkinson, Ian R.; Sun, Jun

    2014-03-01

    The laminar-flow viscosity of ocean and other natural waters consists of a Newtonian aqueous component contributed by water and salts, and a non-Newtonian one contributed mainly by exopolymeric polymers (EPS) derived largely from planktonic algae and bacteria. Phytoplankton and EPS form thin layers in stratified waters, often associated with density discontinuities. A recent model (Jenkinson and Sun, 2011. J. Plankton Res., 33, 373-383) investigated possible thalassorheological control of pycnocline thickness (PT) by EPS secreted by the harmful dinoflagellate Karenia mikimotoi. The model, based on published measurements of viscosity increase by this species, found that whether it can influence PT depends on the relationship between increased viscosity, deformation rates/stresses and length scale, which the present work has investigated. To do this, flow rate vs. hydrostatic pressure (and hence wall stress) was measured in cultures (relative to that in reference water) in capillaries of 5 radii 0.35-1.5 mm, close to oceanic-turbulence Kolmogorov length. We compared cultures of the potentially harmful algae, K. mikimotoi, Alexandrium catenella, Prorocentrum donghaiense, Skeletonema costatum, Phaeodactylum tricornutum and the bacterium Escherichia coli. Drag increase, ascribed to rheological thickening by EPS, occurred in the smallest capillaries, but drag reduction (DR) occurred in the largest ones. Since this occurred at Reynolds numbers Re too small for turbulence (or turbulent DR) to occur, this was laminar-flow DR. It may have been superhydrophobic DR (SDR), associated with the surfaces of the plankton and bacteria. SDR is associated with the self-cleaning Lotus-leaf Effect, in which water and dirt are repelled from surfaces bearing nm- to µm-sized irregularities coated with hydrophobic polymers. Because DR decreased measured viscosity and EPS thickening increased it, we could not validate the model. DR, however, represents hitherto unknown phenomenon in the

  10. Towards Managing Stemphylium Blight of Lentil in the Pacific Northwest

    Science.gov (United States)

    Stemphylium blight of lentil, caused by the fungus Stemphylium botryosum, has recently emerged as a disease problem in the Pacific Northwest, particularly on the recently released lentil cultivar ‘Morena’. The first step toward managing the disease is to correctly identify early signs of the diseas...

  11. Blighted Spaces and the Politics of Everyday Life

    Directory of Open Access Journals (Sweden)

    2003-11-01

    Full Text Available While a great deal is known about the demographic and historical trends that shape the built environment of American cities, much less is known about the politics of everyday life among residents who continue to live in postindustrial neighborhoods. This study seeks to compensate for the current gaps in academic research by conducting spatially informed ethnography in a North Philadelphia community. Specifically, the study will explore the issue of urban "blight" from a cultural geography perspective, primarily by looking at the ways in which "blighted" spaces shape everyday life, and everyday life in turn shapes and produces the spatial environment. In response to these concerns, my study poses the questions: What would it mean to focus on the ways in which human agency, imagination, and subjectivity are shaped by "blighted" geographical locations? What would it mean to pay ethnographic attention to how subjects in given historical conditions are shaped by "blighted" spaces, as well as how they respond to these spaces in culturally specific ways? By incorporating critical interdisciplinary approaches, this study offers a new way of looking at the various practices of daily life - including flexible, informal economic activities and post-welfare related "lifestyles" of resistance. Through the lens of spatial ethnography, the study seeks to elucidate the ways in which postindustrial space interacts with culture, poverty and addiction; as well as the ways in which users continue to appropriate postindustrial spaces in culturally meaningful ways under the aegis of the semi-welfare state.

  12. Integrated Control of Fire Blight with Antagonists and Oxytetracycline

    Science.gov (United States)

    In the Pacific Northwest of the United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of Erwinia amylovora arose. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the duration of inhibitory activity of o...

  13. Can physiology help us to combat late blight in potato?

    NARCIS (Netherlands)

    Struik, P.C.

    2010-01-01

    Late blight is a devastating disease in potato production world-wide. Breeding for resistance is complex because of the versatile and aggressive population of Phytophthora infestans, which overcomes any new genetic source of resistance very rapidly. There are reliable fungicides available to control

  14. Fire blight: applied genomic insights of the pathogen and host

    Science.gov (United States)

    The enterobacterial phytopathogen, Erwinia amylovora, causes fire blight, an invasive disease that threatens a wide range of commercial and ornamental Rosaceae host plants. The response elicited by E. amylovora in its host during disease development is similar to the hypersensitive reaction that ty...

  15. The cold-induced defensin TAD1 confers resistance against snow mold and Fusarium head blight in transgenic wheat.

    Science.gov (United States)

    Sasaki, Kentaro; Kuwabara, Chikako; Umeki, Natsuki; Fujioka, Mari; Saburi, Wataru; Matsui, Hirokazu; Abe, Fumitaka; Imai, Ryozo

    2016-06-20

    TAD1 (Triticum aestivum defensin 1) is induced during cold acclimation in winter wheat and encodes a plant defensin with antimicrobial activity. In this study, we demonstrated that recombinant TAD1 protein inhibits hyphal growth of the snow mold fungus, Typhula ishikariensis in vitro. Transgenic wheat plants overexpressing TAD1 were created and tested for resistance against T. ishikariensis. Leaf inoculation assays revealed that overexpression of TAD1 confers resistance against the snow mold. In addition, the TAD1-overexpressors showed resistance against Fusarium graminearum, which causes Fusarium head blight, a devastating disease in wheat and barley. These results indicate that TAD1 is a candidate gene to improve resistance against multiple fungal diseases in cereal crops.

  16. Late blight in organic potato growing: managing resistance and early tuber growth

    OpenAIRE

    Hospers - Brands, Monique; Timmermans, Bart; van der Putten, Peter; Struik, Paul; Tiemens-Hulscher, Marjolein; Lammerts van Bueren, Edith

    2008-01-01

    In organic potato production yields are often reduced by potato late blight (Phytophthora infestans). Two aspects are important in late blight management: a sufficiently high (field) resistance to late blight, and early tuber formation. With early tuber formation the period of tuber growth is extended at the beginning, and with a high resistance level at the end. In 2006 and 2007 experiments were carried out in which the effects of the physiological age of seed tubers on field resistance ...

  17. Teratogenicity studies on late blighted potatoes in nonhuman primates (Macaca mulatta and Saguinus labiatus).

    Science.gov (United States)

    Allen, J R; Marlar, R J; Chesney, C F; Helgeson, J P; Kelman, A; Weckel, G; Traisman, E; White, J W

    1977-02-01

    Female rhesus monkeys and marmosets were fed a diet containing blighted potatoes (Phytophthora infestans) at a level of 10g/kg per day for at least two weeks prior to breeding and six weeks following conception in order to gain additional information on the association of blighted potatoes and the development of anencephaly and spina bifida in primate species. There was an absence of either of these neural-tube defects in 32 rhesus and 14 marmoset infants whose mothers had received a blighted potato diet. In addition there were no cranial osseous defects. There were, however, two rhesus monkey infants with internal hydrocephalus whose mothers had consumed blighted potatoes.

  18. Epidemiology and integrated control of potato late blight in Europe

    DEFF Research Database (Denmark)

    Cooke, L R; Schepers, H T A M; Hermansen, A;

    2011-01-01

    20 years. The relative importance of the different primary inoculum sources and specific measures for reducing their role, such as covering dumps with plastic and preventing seed tubers from becoming infected, is described for the different regions. In NW Europe, varieties with greater resistance...... tend not to be grown on a large scale. From the grower’s perspective, the savings in fungicide input that can be achieved with these varieties are not compensated by the higher (perceived) risk of blight. Fungicides play a crucial role in the integrated control of late blight. The spray strategies...... in NW Europe and a table of the specific attributes of the most important fungicides in Europe are presented. The development and use of decision support systems (DSSs) in NW Europe are described. In The Netherlands, it is estimated that almost 40% of potato growers use recommendations based...

  19. 绿豆细菌性病害田间药剂防治试验%Field Control Test Against Mung Bean Bacterial Disease

    Institute of Scientific and Technical Information of China (English)

    郑旭

    2015-01-01

    绿豆细菌性病害是影响绿豆产量及品质的重要病害,为选用安全、高效、低毒的防治药剂,以大面积生产用感病品种绿丰2号为材料,选用72%农用硫酸链霉素可湿性粉剂、20%叶枯唑可湿性粉剂、50%福美双可湿性粉剂低、中、高量对绿豆细菌性病害进行防治筛选试验。田间试验结果表明:72%农用链霉素可湿性粉剂对绿豆细菌性病害的防治效果最好,1000、2000、3000倍液处理在第3次药后7、14 d的防治效果均大于70%,第3次药后21 d防效也大于65%;其次是20%叶枯唑可湿性粉剂600、800倍液;50%福美双可湿性粉剂对绿豆细菌性病害基本无效。%Mung bean bacterial disease is an important disease affecting yield and quality of mungbean .Taking the control agent with safty ,high efficiency and low toxicity ,large area production Lyufeng2 as materials ,agri‐cultural streptomycin sulphate 72% wettable power ,20% leaf blight wettable powder ,50% thiram wettable powder ,medium and high amount were taken to prevention and control of screening test against mung bean bacterial diseases .Field trials showed that agricultural streptomycin 72% wettable powder of mung bean bacte‐rial diseases prevention and control of the best effect ,after 7 days and 14 days liquid treatment of control effect were greater than 70% by 1 000 times ,2 000 times and 3 000 times liquid ,after 21 days the drug was the third time control effect was greater than 65% followed by 20% leaf blight wettable powder 600 times and 800 times liquid ;Thiram 50% wettable powder of mung bean bacterial disease was invalid .

  20. Development of late blight resistance and heat tolerance through gamma irradiation of shoot cultures in potato

    International Nuclear Information System (INIS)

    In vitro shoot cultures of two potato varieties viz., Kufri jyoti and Kufri Chandramukhi were gamma irradiated at 20 Gy and 40 Gy. Micro tubers were induced in micro propagated M1V3 generation. For heat tolerance micro tubers were induced at elevated (28C) incubation temperature (optimum being 201C) and were characterized by early sowing, chlorophyll persistence and harvest index. The number of micro tubers/plant was highly reduced at elevated temperature and the resulting tubers exhibited distorted shapes and growth of apical buds. Thus obtained micro tubers exhibited better germination (62.3%) even in early sowing at relatively higher temperature. The progenies from putative heat tolerant plants were grown in the field by sowing at higher temperature for four subsequent generations. Heat tolerant plants segregated in each generation but the frequency of heat tolerant plants increased in the advanced generation. For developing late blight resistance micro tubers produced from irradiated shoot cultures were sown in pots and resulting plants were screened using detached leaf method. The progenies of putative resistant plants grown in the field were artificially inoculated with sporangial inoculum of Phytophthora infection's. Field grown plants exhibited segregation with respect to disease reaction and about 56 per cent plants showed resistance. Segregation was reduced during following generation and the frequency of resistant plants was increased up to 72.3 per cent. Thus, repeated selections has helped in developing stable mutants in both the varieties

  1. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars.

    Directory of Open Access Journals (Sweden)

    Cornelia Chizzali

    Full Text Available Pear (Pyrus communis is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS. Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in 'Harrow Sweet', while only PcBIS2 transcripts were detected in 'Alexander Lucas' and 'Conference'. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight was observed in the transition zone of 'Harrow Sweet', whereas the concentrations were ten times lower in 'Conference' and not even detectable in 'Alexander Lucas'. In 'Harrow Sweet', the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of 'Alexander Lucas' and 'Conference' advanced down to the rootstock, resulting in necrosis of the entire shoots.

  2. Biological control of late blight of potatoes: In vivo and in vitro evaluation of microbial antagonists against tuber blight.

    OpenAIRE

    Hollywood, J. C.

    2004-01-01

    The cost of losses and control measures attributed to late blight of potatoes caused by Phytophthora infestans, are estimated to exceed {dollar}5 billion annually. Breeding for resistance is difficult owing to the tetraploid genotype of potato and current strains of the pathogen have developed resistance to chemical control. Consequently the search for biological control has assumed greater importance. In this investigation an in vivo bioassay was used to select soils antagonistic to late bli...

  3. The Potential of the South American Leaf Blight as a Biological Agent

    OpenAIRE

    Oghenekome Onokpise; Clifford Louime

    2012-01-01

    When asked by the Department of Homeland Security to create potential terrorism scenarios, even “Out of the Box Thinkers” initially failed to come up with the following scenario. Oil tankers, refineries, nuclear plants, etc., are obvious potential terrorists’ targets, and adequate measures are being taken to protect them. However, what if the target were to be a non-food commodity product, such as natural rubber tree plantations located in places as remote as sou...

  4. The Potential of the South American Leaf Blight as a Biological Agent

    Directory of Open Access Journals (Sweden)

    Oghenekome Onokpise

    2012-11-01

    Full Text Available When asked by the Department of Homeland Security to create potential terrorism scenarios, even “Out of the Box Thinkers” initially failed to come up with the following scenario. Oil tankers, refineries, nuclear plants, etc., are obvious potential terrorists’ targets, and adequate measures are being taken to protect them. However, what if the target were to be a non-food commodity product, such as natural rubber tree plantations located in places as remote as southeast Asian countries like Thailand or Indonesia? Would it be of concern? At first thought “maybe not”, but think again. What could the release of a deadly microorganism (fungus/virus/bacteria in a rubber tree plantation in Indonesia, Malaysia or Thailand possibly mean to you or the world economy?

  5. A Sorghum MYB Transcription Factor Induces 3-Deoxyanthocyanidins and Enhances Resistance against Leaf Blights in Maize

    Directory of Open Access Journals (Sweden)

    Farag Ibraheem

    2015-01-01

    Full Text Available Sorghum responds to the ingress of the fungal pathogen Colletotrichum sublineolum through the biosynthesis of 3-deoxyanthocyanidin phytoalexins at the site of primary infection. Biosynthesis of 3-deoxyanthocyanidins in sorghum requires a MYB transcription factor encoded by yellow seed1 (y1, an orthologue of the maize gene pericarp color1 (p1. Maize lines with a functional p1 and flavonoid structural genes do not produce foliar 3-deoxyanthocyanidins in response to fungal ingress. To perform a comparative metabolic analysis of sorghum and maize 3-deoxyanthocyanidin biosynthetic pathways, we developed transgenic maize lines expressing the sorghum y1 gene. In maize, the y1 transgene phenocopied p1-regulated pigment accumulation in the pericarp and cob glumes. LC-MS profiling of fungus-challenged Y1-maize leaves showed induction of 3-deoxyanthocyanidins, specifically luteolinidin. Y1-maize plants also induced constitutive and higher levels of flavonoids in leaves. In response to Colletotrichum graminicola, Y1-maize showed a resistance response.

  6. 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).

  7. Response of germinating barley seeds to Fusarium graminearum: The first molecular insight into Fusarium seedling blight

    DEFF Research Database (Denmark)

    Yang, Fen; Svensson, Birte; Finnie, Christine

    2011-01-01

    Fusarium seedling blight in cereals can result in significant reductions in plant establishment but has not received much attention. The disease often starts during seed germination due to sowing of the seeds infected by Fusarium spp. including Fusarium graminearum. In order to gain the first...... provides the first molecular insight into Fusarium seedling blight....

  8. Estimating the global severity of potato late blight with GIS-linked disease forecast models

    NARCIS (Netherlands)

    Hijmans, R.J.; Forbes, G.A.; Walker, T.S.

    2000-01-01

    Global severity of potato late blight was estimated by linking two disease forecast models, Blitecast and Simcast, to a climate data base in a geographic information system (GIS). The disease forecast models indirectly estimate late blight severity by determining how many sprays are needed during a

  9. Fine mapping of the Ph-3 gene conferring resistance to late blight (Phytophthora infestans) in tomato

    NARCIS (Netherlands)

    Zhang, C.Z.; Liu, L.; Zheng, Z.; Sun, Y.Y.; Zhou, L.X.; Yang, Y.H.; Cheng, F.; Zhang, Z.H.; Wang, X.W.; Huang, S.W.; Xie, B.Y.; Du, Y.C.; Bai, Y.; Li, J.M.

    2013-01-01

    Late blight, caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary, is a devastating disease for tomato and potato crops. In the past decades, many late blight resistance (R) genes have been characterized in potato. In contrast, less work has been conducted on tomato. The Ph-3 gene

  10. Analysing potato late blight control as a social-ecological system using fuzzy cognitive mapping

    NARCIS (Netherlands)

    Pacilly, Francine C.A.; Groot, Jeroen C.J.; Hofstede, Gert Jan; Schaap, Ben F.; Lammerts van Bueren, Edith

    2016-01-01

    Potato late blight, caused by Phytophthora infestans, is one of the main diseases in potato production, causing major losses in yield. Applying environmentally harmful fungicides is the prevailing and classical method for controlling late blight, thus contaminating food and water. There is theref

  11. 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...

  12. Introduction of a rice blight resistance gene, Xa21, into five Chinese rice varieties through an Agrobacterium-mediated system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A cloned gene, Xa21 was transferred into five widely-used Chinese rice varieties through an Agrobacterium-mediated system, and over 110 independent transgenic lines were obtained. PCR and Southern analysis of transgenic plants revealed the integration of the whole Xa21 gene into the host genomes. The integrated Xa21 gene was stably inherited, and segregated in a 3∶1 ratio in the selfed T1 generation when one copy of the gene was integrated in the transformants. Inoculation tests displayed that transgenic T0 plants and Xa21 PCR-positive T1 plants were highly resistant to bacterial blight disease. The selected Xa21 homozygous resistant transgenic lines with desirable qualities may be propagated as new varieties or utilized in hybrid rice breeding.

  13. Introduction of a rice blight resistance gene, Xa21, into five Chinese rice varieties through an Agrobacterium -mediated system

    Institute of Scientific and Technical Information of China (English)

    翟文学; 李晓兵; 田文忠; 周永力; 潘学彪; 曹守云; 赵显峰; 赵彬; 章琦; 朱立煌

    2000-01-01

    A cloned gene, Xa21 was transferred into five widely-used Chinese rice varieties through an Agrobacterium-mediated system, and over 110 independent transgenic lines were obtained. PCR and Southern analysis of transgenic plants revealed the integration of the whole Xa21 gene into the host genomes. The integrated Xa21 gene was stably inherited, and segregated in a 3 : 1 ratio in the selfed T1 generation when one copy of the gene was integrated in the transfor-mants. Inoculation tests displayed that transgenic T0 plants and Xa21 PCR-positive T1 plants were highly resistant to bacterial blight disease. The selected Xa21 homozygous resistant transgenic lines with desirable qualities may be propagated as new varieties or utilized in hybrid rice breeding.

  14. Biological Efficacy of Streptomyces sp. Strain BN1 against the Cereal Head Blight Pathogen Fusarium graminearum

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-03-01

    Full Text Available Fusarium head blight (FHB caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

  15. Resistance Evaluation to Sheath Blight in Transgenic Rice Lines

    Institute of Scientific and Technical Information of China (English)

    LIAi-hong; XuXin-ping; DAIZheng-yuan; CHENZong-xiang; LIBao-jian; ZHANGHong-xi; PANXue-biao

    2004-01-01

    Resistance of forty one homozygous rice lines transformed with chitinase gene (RC24) and β-1,3-glucanse gene (β-1,3-Glu) to sheath blight was analyzed by inoculation. Among different lines, the resistance had significant differences according to the result by cluster analysis. The lines could be categorized into resistant, moderately resistant, moderately susceptible and susceptible typcs, while 92.1% of which belonging to moderately resistant or moderately susceptible type. For different resistant or susceptible lines, the resistance to rice sheath blight was remarkable correlated with the chitinase activity of transgenic lines except resistant type lines, in which enzyme activity coded by target gene was lower than moderately resistant type. The chitinase activity of transgenic lines tested at different time after inoculation or different organs of the same plant was uniform, which suggested that the expression of chitinase gene was constitutive in nature. Check varieties' chitinase acdvity would change at different time after inoculation and reach a peak at sometime, but it had no difference at various parts of the same plant.

  16. Resistance Evaluation to Sheath Blight in Transgenic Rice Lines

    Institute of Scientific and Technical Information of China (English)

    LI Ai-hong; XU Xin-ping; DAI Zheng-yuan; CHEN Zong-xiang; LI Bao-jian; ZHANG Hong-xi; PAN Xue-biao

    2004-01-01

    Resistance of forty-one homozygous rice lines transformed with chitinase gene (RC24) and β-1,3 -glucanse gene (β-1,3-Glu) to sheath blight was analyzed by inoculation. Among different lines, the resistance had significant differences according to the result by cluster analysis. The lines could be categorized into resistant, moderately resistant, moderately susceptible and susceptible types, while 92.1% of which belonging to moderately resistant or moderately susceptible type. For different resistant or susceptible lines, the resistance to rice sheath blight was remarkable correlated with the chitinase activity of transgenic lines except resistant type lines, in which enzyme activity coded by target gene was lower than moderately resistant type. The chitinase activity of transgenic lines tested at different time after inoculation or different organs of the same plant was uniform, which suggested that the expression of chitinase gene was constitutive in nature. Check varieties' chitinase activity would change at different time after inoculation and reach a peak at sometime, but it had no difference at various parts of the same plant.

  17. Comparative transcript profiling by SuperSAGE identifies novel candidate genes for controlling potato quantitative resistance to late blight not compromised by late maturity.

    Directory of Open Access Journals (Sweden)

    Astrid M. Draffehn

    2013-11-01

    Full Text Available Resistance to pathogens is essential for survival of wild and cultivated plants. Pathogen susceptibility causes major losses of crop yield and quality. Durable field resistance combined with high yield and other superior agronomic characters are therefore important objectives in every crop breeding program. Precision and efficacy of resistance breeding can be enhanced by molecular diagnostic tools, which result from knowledge of the molecular basis of resistance and susceptibility. Breeding uses resistance conferred by single R genes and polygenic quantitative resistance. The latter is partial but considered more durable. Molecular mechanisms of plant pathogen interactions are elucidated mainly in experimental systems involving single R genes, whereas most genes important for quantitative resistance in crops like potato are unknown. Quantitative resistance of potato to Phytophthora infestans causing late blight is often compromised by late plant maturity, a negative agronomic character. Our objective was to identify candidate genes for quantitative resistance to late blight not compromised by late plant maturity. We used diagnostic DNA-markers to select plants with different field levels of maturity corrected resistance (MCR to late blight and compared their leaf transcriptomes before and after infection with P. infestans using SuperSAGE (serial analysis of gene expression technology and next generation sequencing. We identified 2034 transcripts up or down regulated upon infection, including a homolog of the kiwi fruit allergen kiwellin. 806 transcripts showed differential expression between groups of genotypes with contrasting MCR levels. The observed expression patterns suggest that MCR is in part controlled by differential transcript levels in uninfected plants. Functional annotation suggests that, besides biotic and abiotic stress responses, general cellular processes such as photosynthesis, protein biosynthesis and degradation play a role

  18. Multiple hydrolases in bean leaves (Phaseolus vulgaris L.) and the effect of the halo blight disease caused by Pseudomonas phaseolicola (Burkh.) Dowson.

    Science.gov (United States)

    Rudolph, K; Stahmann, M A

    1966-03-01

    Multiple forms of hydrolytic enzymes were demonstrated in extracts of healthy bean leaves (Phascolus vulgaris L.) and bean leaves infected with the halo blight organism [Pseudomonas phaseolicola (Burkh.) Dowson] by polyacrylamide disc electrophoresis. Bean leaves contained up to 4 acid phosphatase bands, 9 esterase bands active towards alpha-naphthyl acetate, and 7 esterase bands towards alpha-naphthyl butyrate. Only low or no activity was found for alkaline phosphatase, lipase, and aminopeptidase. Two artifacts are described which were observed with the lead phosphate method for acid phosphatase and the Tween method for demonstration of lipase. After infection with the halo blight organism the major acid phosphatase of the host increased during early and decreased at later infection stages. An acid phosphatase of bacterial origin with a more neutral pH optimum could be demonstrated in infected leaves. It is suggested that the bacterial acid phosphatase plays a role in uptake of metabolites by the pathogen. Several esterase bands decreased after infection. One host band with activity towards alpha-naphthyl butyrate increased. Also the pathogen showed an esterase band with high activity towards alpha-naphthyl butyrate. PMID:5906374

  19. First Occurence of Fire Blight on Apricot (Prunus armeniaca) in Hungary

    OpenAIRE

    Végh, Anita; László PALKOVICS

    2013-01-01

    During July 2012, a severe unusual disease symptom was observed on young shoots on apricot (Prunus armeniaca 10/13 hybrid) in the city of Pomáz, near Budapest. The naturally infected shoots showed typical symptoms of fire blight including terminal shoots with brown to black necrotic lesions. Symptoms were the same as fire blight symptoms reported from other hosts and locations. The first occurrence of fire blight on an apricot tree in Europe was recorded in Czech Republic in 2011. Samples of ...

  20. 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.

  1. Effect of simulated rain on the efficiency of fungicides in potato late blight and early blight control

    Directory of Open Access Journals (Sweden)

    Jesus Guerino Tofoli

    2014-12-01

    Full Text Available Rainfastness of fungicides used in the control of late blight (Phytophthora infestans and early blight (Alternaria solani of potato was evaluated under green house and laboratory conditions. ‘Agata’ and ‘Monalisa’ plants treated with fungicides against both diseases were subjected to 20 mm controlled rain simulation for 6 min at 30 min, 1, 2, and 4 h after application. Once all leaves had dried, foliar discs were transferred to Petri dishes and inoculated with the respective pathogens. The plates were then incubated in a BOD chamber for a 12-h photoperiod at 18°C and 25°C, respectively. Disease severity was evaluated by determining the area (% of the foliar discs affected by disease on 5 and 7 days post-inoculation. The results suggest that systemic or inherent tenacity fungicides were less influenced by the simulated rain as compared to contact fungicides. An increase in drying time promoted higher control levels of both diseases, indicating a better retention and absorption of the tested fungicides.

  2. Studies on the Control of Ascochyta Blight in Field Peas (Pisum sativum L.) Caused by Ascochyta pinodes in Zhejiang Province, China.

    Science.gov (United States)

    Liu, Na; Xu, Shengchun; Yao, Xiefeng; Zhang, Guwen; Mao, Weihua; Hu, Qizan; Feng, Zhijuan; Gong, Yaming

    2016-01-01

    Ascochyta blight, an infection caused by a complex of Ascochyta pinodes, Ascochyta pinodella, Ascochyta pisi, and/or Phoma koolunga, is a destructive disease in many field peas (Pisum sativum L.)-growing regions, and it causes significant losses in grain yield. To understand the composition of fungi associated with this disease in Zhejiang Province, China, a total of 65 single-pycnidiospore fungal isolates were obtained from diseased pea samples collected from 5 locations in this region. These isolates were identified as Ascochyta pinodes by molecular techniques and their morphological and physiological characteristics. The mycelia of ZJ-1 could penetrate pea leaves across the stomas, and formed specific penetration structures and directly pierced leaves. The resistance level of 23 available pea cultivars was tested against their representative isolate A. pinodes ZJ-1 using the excised leaf-assay technique. The ZJ-1 mycelia could penetrate the leaves of all tested cultivars, and they developed typical symptoms, which suggested that all tested cultivars were susceptible to the fungus. Chemical fungicides and biological control agents were screened for management of this disease, and their efficacies were further determined. Most of the tested fungicides (11 out of 14) showed high activity toward ZJ-1 with EC50 pea-related niches and significantly reduced the severity of disease under greenhouse and field conditions. To our knowledge, this is the first study on ascochyta blight in field peas, and results presented here will be useful for controlling the disease in this area.

  3. Evaluation of the BlightPro Decision Support System for Management of Potato Late Blight Using Computer Simulation and Field Validation.

    Science.gov (United States)

    Small, Ian M; Joseph, Laura; Fry, William E

    2015-12-01

    The objective of this study was to evaluate the utility of the BlightPro decision support system (DSS) for late blight management using computer simulation and field tests. Three fungicide schedules were evaluated: (i) calendar-based (weekly) applications, (ii) applications according to the DSS, or (iii) no fungicide. Simulation experiments utilized 14 years of weather data from 59 locations in potato-producing states. In situations with unfavorable weather for late blight, the DSS recommended fewer fungicide applications with no loss of disease suppression; and, in situations of very favorable weather for late blight, the DSS recommended more fungicide applications but with improved disease suppression. Field evaluation was conducted in 2010, 2011, 2012, and 2013. All experiments involved at least two cultivars with different levels of resistance. DSS-guided and weekly scheduled fungicide treatments were successful at protecting against late blight in all field experiments. As expected, DSS-guided schedules were influenced by prevailing weather (observed and forecast) and host resistance and resulted in schedules that maintained or improved disease suppression and average fungicide use efficiency relative to calendar-based applications. The DSS provides an interactive system that helps users maximize the efficiency of their crop protection strategy by enabling well-informed decisions.

  4. Antifungal Action of Ginkgo biloba Outer Seedcoat on Rice Sheath blight

    Directory of Open Access Journals (Sweden)

    Tae-Seok Oh

    2015-03-01

    Full Text Available From study of antifungal actions on the rice sheath blight by using the extract of Ginkgo biloba outer seedcoats, we found that the extracts of Ginkgo biloba outer seedcoats of all treatment concentrations had inhibited the rice sheath blight. Among them, the most effective concentration was 250 mg/l at which the growth of microbe was 26 mm and even at the packaging test, when sprayed the G. biloba outer seedcoats at the level of 250 mg/l, the damage rate of the rice sheath blight was identified as 13%. As a result investigating the antifungal activity by separating polysaccharides from G. biloba outer seedcoats, it showed that the clear zone of 14 mm or more was formed at the concentration of 250 mg/l or higher. Based on these results, we concluded that the G. biloba outer seedcoat is a natural substance with the antifungal activity on the rice sheath blight.

  5. Integrating cultural control methods for tomato late blight (Phytophthora infestans) in Uganda

    NARCIS (Netherlands)

    Tumwine, J.; Frinking, H.D.; Jeger, M.J.

    2002-01-01

    Cultural control measures against tomato late blight (Phytophthora infestans) were evaluated in six field experiments over 3 years in Uganda. Each experiment included sanitation (removal of diseased plant tissues), fungicide (mancozeb) application, and an untreated control, as standard treatments. L

  6. Expression of viral EPS-depolymerase reduces fire blight susceptibility in transgenic pear.

    Science.gov (United States)

    Malnoy, Mickaël; Faize, Mohamed; Venisse, Jean-Stéphane; Geider, Klaus; Chevreau, Elisabeth

    2005-02-01

    Erwinia amylovora is the causal agent of fire blight of Maloideae. One of the main pathogenicity factors of this bacterium is the exopolysaccharide (EPS) of its capsule. In this paper, we used genetic transformation tools to constitutively express an EPS-depolymerase transgene in the pear (Pyrus communis L.) cv. Passe Crassane with the aim of decreasing its high susceptibility to fire blight. Expression of the depolymerase gene in 15 independent transgenic clones led, on average, to low depolymerase activity, although relatively high expression was observed at the transcriptional and translational levels. Only two of the transgenic clones (9X and 10M) consistently showed a decrease in fire blight susceptibility in vitro and in the greenhouse. These clones were also among the highest expressers of depolymerase at the RNA and enzyme activity levels. The correlation observed among all transgenic clones between depolymerase expression and fire blight resistance suggested the potential of this strategy.

  7. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars

    Science.gov (United States)

    Chizzali, Cornelia; Swiddan, Asya K.; Abdelaziz, Sahar; Gaid, Mariam; Richter, Klaus; Fischer, Thilo C.; Liu, Benye; Beerhues, Ludger

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in ‘Harrow Sweet’, while only PcBIS2 transcripts were detected in ‘Alexander Lucas’ and ‘Conference’. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of ‘Harrow Sweet’, whereas the concentrations were ten times lower in ‘Conference’ and not even detectable in ‘Alexander Lucas’. In ‘Harrow Sweet’, the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of ‘Alexander Lucas’ and ‘Conference’ advanced down to the rootstock, resulting in necrosis of the entire shoots. PMID:27410389

  8. The Identity of a Pea Blight Fungus in South Africa *

    Directory of Open Access Journals (Sweden)

    K. T. van Warmelo

    1966-12-01

    Full Text Available The perfect stage of Ascochyta pinodes (Berk. & Blox. Jones, a cause of pea blight in Natal, was compared with type material of  Sphaeria pinodes Berk, and Blox.,  Mycosphaerella pinodes (Berk. & Blox. Stone, and  Didymella pinodes (Berk. & Blox. Petrak and the development o f its ascocarps studied. Two types of ascocarp were found on the material of  Didymella pinodes, one perithecial and the other ascolocular in structure. The ascocarp of the South African fungus was typically ascolocular in development and construction and similar to that of other species of Mycosphaerella. These ascocarps were identical to those of  Sphaeria pinodes and Mycosphaerella pinodes and the ascolocular ascocarps of the  DidymeUa pinodes material. In development and morphology this fungus agrees more closely with the original generic concepts of the genus Mycosphaerella Joh. than with  Didymella Sacc. and should thus be named Mycosphaerella pinodes (Berk. & Blox. Stone.

  9. Preservation methods for isolates of ascochyta blight fungi

    Directory of Open Access Journals (Sweden)

    Joanna Marcinkowska

    2014-08-01

    Full Text Available Isolates of ascochyta blight fungi, two of Ascochyta pisi, four of Mycosphaerella pinodes and four of Phoma pinodella were stored: A - on slants under mineral oil, B - on CN's medium agar disks, and as conidial suspension: C - in glycerine, D · in water. Viability and pathogenicity of recovered cultures after each consecutive year were assesed from 1991 to 1999. The compared parameters were first of all strongly influenced by the preservation method, but fungus species and number of years had a minor importance. The best for longer storage was method "A" because after 9 years the isolates were viable, highly pathogenic, and cultures recovered from them were clean. Thc method "C'' is good for short keeping (2-3 years, as conidia in vials need only small space and gave clean cultures.

  10. Unveiling and deploying durability of late blight resistance in potato : from natural stacking to cisgenic stacking

    OpenAIRE

    Kwang-Ryong Jo

    2013-01-01

    The potato, which receives an increased attention as a food crop, has long been in threats from the oomycete Phytophthora infestans, the causal agent of late blight. This disease still remains the most important constraint in potato producing regions of the world. It might cause the complete destruction of the foliage and tubers of potato if meteorological conditions are conducive to the onset and spread of late blight epidemics. Although fungicides applications provide sufficient levels of l...

  11. Chestnut blight in Portugal : spread and populational structure of Cryphonectria parasitica

    OpenAIRE

    Bragança, Maria Helena Pires, 1964-

    2007-01-01

    Tese de doutoramento em Biologia (Microbiologia), apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2008 Cryphonectria parasitica, the causal agent of chestnut blight, has been considered one of the most important mortality factors of the sweet chestnut Castanea sativa all over the world. To evaluate the current distribution of chestnut blight in Portugal, all chestnut growing regions across the entire country were screened, a total of 191 chestnut stands were surveyed...

  12. Delphinella Shoot Blight on Abies lasiocarpa Provenances in Norway

    Directory of Open Access Journals (Sweden)

    Venche Talgø

    2015-12-01

    Full Text Available Delphinella shoot blight (Delphinella abietis attacks true firs (Abies spp. in Europe and North America. Especially subalpine fir (A. lasiocarpa, one of the main Christmas tree species in Norway, is prone to the disease. The fungus kills current year needles, and in severe cases entire shoots. Dead needles become covered with black fruiting bodies, both pycnidia and pseudothecia. Delphinella shoot blight has mainly been a problem in humid, coastal regions in the northwestern part of Southern Norway, but, probably due to higher precipitation in inland regions during recent years, heavy attacks were found in 2011 in a field trial with 76 provenances of subalpine fir in Southeastern Norway. However, the amount of precipitation seemed less important once the disease had established in the field. Significant differences in susceptibility between provenances were observed. In general, the more bluish the foliage was, the healthier the trees appeared. The analysis of provenance means indicated that, at least for the southern range, the disease ratings were correlated with foliage color. This study also includes isolation, identification, a pathogenicity test, a seed test and electron microscopy of the wax layer on the needles. The fungus was identified based on the morphology of spores and by sequencing the Internal Transcribed Spacer (ITS regions of the ribosomal DNA. Koch’s postulates were fulfilled. The fungus was found present on newly harvested seeds and may therefore spread via international seed trade. When comparing the wax layers on green and blue needles, those of the latter were significantly thicker, a factor that may be involved in disease resistance.

  13. Cultural Heritage in the Gulf: Blight or Blessing?

    Directory of Open Access Journals (Sweden)

    Djamel Boussaa

    2014-12-01

    Full Text Available In the Gulf and after gaining independence in the 1960s and 1970s many cities witnessed a staggering rapid urban growth. The urban centers, which formed the central parts of these cities, underwent continuous pressures of destruction and redevelopment. A large number of these centers have been often demolished and replaced by alien imported high-rise buildings. The urban cores which escaped complete demolition have survived as isolated pockets in the middle of hybrid environments. This dilemma raises important questions; is this surviving cultural heritage blight or blessing? Is it "blight" and obstacle that stifles our cities from moving forward to aspire for a bright and prosperous future, or is it "blessing" an asset that can form a major catalyst to promote our cities while maintaining strong roots with their past? Accordingly, what should be the future of these surviving historic centers? Will they be demolished to pave way for more ambitious growth or can they be conserved and sustained for present and future generations? Will the historic city, the heart of urban life and the main protector of our cities identities, survive and continue to be places for living within the emerging global cities of today and tomorrow? This paper attempts to highlight the importance of dealing with the conservation and development issue, by raising and discussing the following question: How can our cultural heritage be a setting of appropriate conservation and development in the emerging global environments? In order to discuss this issue, three historic cities from the Gulf; Old Dubai in UAE, Old Jeddah in Saudi Arabia and Old Doha in Qatar will form the setting of this research.

  14. Functional analysis of OsPGIP1 in rice sheath blight resistance.

    Science.gov (United States)

    Wang, Rui; Lu, Liaoxun; Pan, Xuebiao; Hu, Zongliang; Ling, Fei; Yan, Yan; Liu, Yemao; Lin, Yongjun

    2015-01-01

    As one of the most devastating diseases of rice, sheath blight causes severe rice yield loss. However, little progress has been made in rice breeding for sheath blight resistance. It has been reported that polygalacturonase inhibiting proteins can inhibit the degradation of the plant cell wall by polygalacturonases from pathogens. Here, we prokaryotically expressed and purified OsPGIP1 protein, which was verified by Western blot analysis. Activity assay confirmed the inhibitory activity of OsPGIP1 against the PGase from Rhizoctonia solani. In addition, the location of OsPGIP1 was determined by subcellular localization. Subsequently, we overexpressed OsPGIP1 in Zhonghua 11 (Oryza sativa L. ssp. japonica), and applied PCR and Southern blot analysis to identify the positive T0 transgenic plants with single-copy insertions. Germination assay of the seeds from T1 transgenic plants was carried out to select homozygous OsPGIP1 transgenic lines, and the expression levels of OsPGIP1 in these lines were analyzed by quantitative real-time PCR. Field testing of R. solani inoculation showed that the sheath blight resistance of the transgenic rice was significantly improved. Furthermore, the levels of sheath blight resistance were in accordance with the expression levels of OsPGIP1 in the transgenic lines. Our results reveal the functions of OsPGIP1 and its resistance mechanism to rice sheath blight, which will facilitate rice breeding for sheath blight resistance. PMID:25488398

  15. Inheritance Analysis and Identification of SSR Markers Linked to Late Blight Resistant Gene in Tomato

    Institute of Scientific and Technical Information of China (English)

    ZHU Hai-shan; WU Tao; ZHANG Zhen-xian

    2006-01-01

    Late blight caused by Phytophthora infestans is the most serious disease of tomato production in China. Studies on the genetics of resistance and identification of molecular markers are very useful for breeding late blight resistant varieties.The objective of this paper was to study the inheritance of late blight resistance and identify simple sequence repeat (SSR)markers associated with resistance allele in tomato (Lycopersicon esculentum Mill). The results came from an F2 progeny of 241 plants derived from a cross between 5# inbred line that is susceptible to late blight and a resistant accession CLN2037E. The late blight responses of F2 plants were tested by artificially inoculation of detached-leaflets in plate and natural infection assayed under greenhouse conditions. Both methods showed that the resistance is dominant and inherited as monogenic trait. Genetic mapping and linkage analysis showed that the late blight resistance gene Ph-ROL was located on chromosome 9 with a genetic distance of 5.7 cM to the SSR marker TOM236.

  16. Evaluation of Nutritive Value of Water Hyacinth (Eichhornia crassipes) Leaf Meal in Compound Diets for Rohu, Labeo rohita (Hamilton, 1822) Fingerlings after Fermentation with Two Bacterial Strains Isolated from Fish Gut

    OpenAIRE

    Saha, Sangbrita; Ray, Arun Kumar

    2011-01-01

    Nine isonitrogenous (30% crude protein approximately) and isocaloric (18.23 kJ g-1) experimental diets (D1-D9) were formulated either with raw or treated (fermented with fish intestinal bacteria) Eichhornia crassipes leaf meal at 20%, 30% and 40% levels replacing other ingredients partially from a fish meal based reference diet (RD). Two specific strains of fish intestinal bacteria, Bacillus subtilis CY5 (isolated from Cyprinus carpio) and B. megaterium CI3 (isolated from Ctenopharyngodon id...

  17. Development of forecasting elements for minimization of fungicide treatment in potato protection against early blight in Moscow region

    OpenAIRE

    Penjkin Roman V.; Doroškina Ljudmila A.; Smirnov Aleksej N.

    2013-01-01

    Early blight of potato (the agent is imperfect fungus Alternaria alternata (Fr.) Keissl.) is a serious disease of potatoes under hot conditions. This disease is important in the regions of Eastern and Southern Europe, Asia and Africa. It is controlled with intensive application of fungicides commonly used against late blight. However, currently fungicides cause undesirable damage to humans and the environment. Elements of forecasting the early blight have been developed in order to mini...

  18. Overexpressing CYP71Z2 enhances resistance to bacterial blight by suppressing auxin biosynthesis in rice.

    Directory of Open Access Journals (Sweden)

    Wenqi Li

    Full Text Available The hormone auxin plays an important role not only in the growth and development of rice, but also in its defense responses. We've previously shown that the P450 gene CYP71Z2 enhances disease resistance to pathogens through regulation of phytoalexin biosynthesis in rice, though it remains unclear if auxin is involved in this process or not.The expression of CYP71Z2 was induced by Xanthomonas oryzae pv. oryzae (Xoo inoculation was analyzed by qRT-PCR, with GUS histochemical staining showing that CYP71Z2 expression was limited to roots, blades and nodes. Overexpression of CYP71Z2 in rice durably and stably increased resistance to Xoo, though no significant difference in disease resistance was detected between CYP71Z2-RNA interference (RNAi rice and wild-type. Moreover, IAA concentration was determined using the HPLC/electrospray ionization/tandem mass spectrometry system. The accumulation of IAA was significantly reduced in CYP71Z2-overexpressing rice regardless of whether plants were inoculated or not, whereas it was unaffected in CYP71Z2-RNAi rice. Furthermore, the expression of genes related to IAA, expansin and SA/JA signaling pathways was suppressed in CYP71Z2-overexpressing rice with or without inoculation.These results suggest that CYP71Z2-mediated resistance to Xoo may be via suppression of IAA signaling in rice. Our studies also provide comprehensive insight into molecular mechanism of resistance to Xoo mediated by IAA in rice. Moreover, an available approach for understanding the P450 gene functions in interaction between rice and pathogens has been provided.

  19. Function of TALE1Xam in cassava bacterial blight: a transcriptomic approach

    OpenAIRE

    Muñoz Bodnar, Alejandra

    2012-01-01

    Xanthomonas axonopodis pv. manihotis (Xam) en una bacteria gram negativa responsable del añublo bacteriano de la yuca. La yuca (Manihot esculenta Crantz) es una de las fuentes más importantes de carbohidratos para más de 1000 millones de personas alrededor del mundo y representa igualmente una fuente importante de energía por las altas concentraciones de almidón en sus raíces. El añublo bacteriano de la yuca representa una limitación importante para el cultivo masivo de este alimento, sin ...

  20. Constitutive expression of the xylanase inhibitor TAXI-III delays Fusarium head blight symptoms in durum wheat transgenic plants.

    Science.gov (United States)

    Moscetti, Ilaria; Tundo, Silvio; Janni, Michela; Sella, Luca; Gazzetti, Katia; Tauzin, Alexandra; Giardina, Thierry; Masci, Stefania; Favaron, Francesco; D'Ovidio, Renato

    2013-12-01

    Cereals contain xylanase inhibitor (XI) proteins which inhibit microbial xylanases and are considered part of the defense mechanisms to counteract microbial pathogens. Nevertheless, in planta evidence for this role has not been reported yet. Therefore, we produced a number of transgenic plants constitutively overexpressing TAXI-III, a member of the TAXI type XI that is induced by pathogen infection. Results showed that TAXI-III endows the transgenic wheat with new inhibition capacities. We also showed that TAXI-III is correctly secreted into the apoplast and possesses the expected inhibition parameters against microbial xylanases. The new inhibition properties of the transgenic plants correlate with a significant delay of Fusarium head blight disease symptoms caused by Fusarium graminearum but do not significantly influence leaf spot symptoms caused by Bipolaris sorokiniana. We showed that this contrasting result can be due to the different capacity of TAXI-III to inhibit the xylanase activity of these two fungal pathogens. These results provide, for the first time, clear evidence in planta that XI are involved in plant defense against fungal pathogens and show the potential to manipulate TAXI-III accumulation to improve wheat resistance against F. graminearum.

  1. Metabolic versatility and antibacterial metabolite biosynthesis are distinguishing genomic features of the fire blight antagonist Pantoea vagans C9-1.

    Directory of Open Access Journals (Sweden)

    Theo H M Smits

    Full Text Available BACKGROUND: Pantoea vagans is a commercialized biological control agent used against the pome fruit bacterial disease fire blight, caused by Erwinia amylovora. Compared to other biocontrol agents, relatively little is currently known regarding Pantoea genetics. Better understanding of antagonist mechanisms of action and ecological fitness is critical to improving efficacy. PRINCIPAL FINDINGS: Genome analysis indicated two major factors Contribute to biocontrol activity: competition for limiting substrates and antibacterial metabolite production. Pathways for utilization of a broad diversity of sugars and acquisition of iron were identified. Metabolism of sorbitol by P. vagans C9-1 may be a major metabolic feature in biocontrol of fire blight. Biosynthetic genes for the antibacterial peptide pantocin A were found on a chromosomal 28-kb genomic island, and for dapdiamide E on the plasmid pPag2. There was no evidence of potential virulence factors that could enable an animal or phytopathogenic lifestyle and no indication of any genetic-based biosafety risk in the antagonist. CONCLUSIONS: Identifying key determinants contributing to disease suppression allows the development of procedures to follow their expression in planta and the genome sequence contributes to rationale risk assessment regarding the use of the biocontrol strain in agricultural systems.

  2. [Bacterial diseases of rape].

    Science.gov (United States)

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

    2012-01-01

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

  3. Effectiveness of fungicide-free approaches to the protection of potato and tomato against late blight

    Directory of Open Access Journals (Sweden)

    Smirnov Aleksej N.

    2011-01-01

    Full Text Available The article describes fungicide-free ecologically tolerant technologies for the protection of potato and tomato against Phytophthora infestans (Mont. de Bary, agent of late blight of these crops. It has been proved that potato cultivars with field resistance (Lugovskoy provide a protection level comparable to the effectiveness of modern fungicides. Plant extracts from Southern plants can be used as biopesticides in order to additionally suppress the development of late blight. For example, extracts of four species from Yemen (fam. Asteraceae: Psiadia arabica Jaup and Spach; fam. Lamiaceae: Lawsonia inermis L ; Dodonea viscos L ; Euryops arabicus Steud. ex Jaub and Spach were capable of suppressing late blight development on potato. On the contrary, plant growth regulators, Novosil (active compound triterpene acids, Larixin (active compound dihydroquerticin, and Terpenol (active compound triterpene acids, in spite of the periods of high efficiency against late blight, do not provide satisfying effect since these substances could sometimes even promote a pathogen development. Also, vaccination of tomato with attenuated strain of tobacco mosaic virus (TMV could improve viability and immune status of plants under normal conditions, and in the case of stress situation it promoted weakness of plants and P. infestans infection. In Eastern Europe, fungicide-free technologies for the protection of potato and tomato against late blight, corresponding to the ecological criterion, should be additionally elaborated and tested for potato and tomato cropping.

  4. Quantitative Effects of Early and Late Blights on Tomato Yields in Cameroon

    Directory of Open Access Journals (Sweden)

    Fontem, DA.

    2003-01-01

    Full Text Available Early blight caused by Alternaria solani and late blight caused by Phytophthora infestans are the major diseases of tomato (Lycopersicon esculentum in Cameroon. The effect of both diseases on fruit yield was evaluated during the 1995 growing season in Dschang, Cameroon.Ten varieties were planted in the first trial (March-July and nine in the second (July- November. In both trials, plots were sprayed weekly with Ridomil Plus (2.0 kg/ha before flowering and with maneb (1.6 kg/ha after flowering. Early blight was more severe in the early part of the first trial, while late blight caused most damage during the second. Marketable yields varied according to variety. High yields in sprayed plots were obtained in Dona F1 (61.63 t/ha and Heinz 1370 (68.24 t/ha during the first trial, and in Fline (58.35 t/ha, Mecline (64.25 t/ha, and Moboline (55.16 t/ha during the second trial. Percent fruit infection in sprayed plots caused by both diseases varied according to variety from 12 to 65% in the first season and from 14 to 52% in the second, while losses in marketable yields for both blights were as high as 100% in unsprayed plots.

  5. Gram-Positive Bacteria Associated with Rice in China and Their Antagonists Against the Pathogens of Sheath Blight and Bakanae Disease in Rice

    Institute of Scientific and Technical Information of China (English)

    LUO Jin-yan; XIE Guan-lin; LI Bin; LUO Yuan-chan; ZHAO Li-han; WANG Xiao; LIU Bo; LI Wen

    2005-01-01

    It is necessary to understand the bacterial populations associated with rice so as to provide more information and natural resources for effective management of major diseases in rice. A survey on screening and identification of gram-positive bacteria was conducted during 1998-2004. Seven hundred and fifty-six rice samples were collected from Zhejiang, Jiangsu, Fujian and Yunnan Provinces, China. Over 1000 bacterial isolates were isolated and tested for colony morphology, pathogenicity, and some characteristics of bacteriology including Gram staining, fluorescent pigment on Kings medium B and microscopic observation for endospore. Together with five standard reference strains, 74 representative gram-positive bacterial isolates were confirmed by Biolog and gas chromatographic analysis of fatty acid methyl esters. Five bacterial species of Bacillus and other three genera were identified and isolates from Bacillus sublitis and Bacillus megaterium, exhibited the most effective inhibition against the pathogens of sheath blight and bakanae disease of rice. A few isolates from Bacillus pumilus and Bacillus megaterium showed weak virulent on rice together with some virulent isolates, dsk should be considered when isolates from these species were screened for biocontrol agents.

  6. Dynamics of Cryphonectria hypovirus infection in chestnut blight cankers.

    Science.gov (United States)

    Bryner, Sarah Franziska; Prospero, Simone; Rigling, Daniel

    2014-09-01

    Virulent strains of the chestnut blight fungus Cryphonectria parasitica cause lethal bark cankers on chestnut trees. Infection of C. parasitica with Cryphonectria hypovirus 1 in Europe biologically controls this disease, leading to nonlethal and inactive cankers. Unexpectedly, virus-free C. parasitica strains have been isolated from inactive cankers. In this study, we compared the virulence of virus-infected and virus-free C. parasitica strains isolated from either inactive or active cankers on chestnut seedlings and sprouts. In the seedling experiment, we assessed canker growth and seedling mortality. In the sprout experiment, we also assessed canker growth and made fungal reisolations to determine virus infection and immigration of foreign vegetative compatibility (vc) types over a period of 13 years in a coppice forest. Overall, the virulence of virus-free C. parasitica strains isolated from inactive versus active cankers did not differ. Significant differences were only attributed to virus infection. Virus infection and fungal strain composition in cankers changed over time. Foreign vc types immigrated into cankers and virus-free cankers became virus-infected within a few years. Most of the cankers were callused over time and became inactive. However, we observed that the virus did not always persist in these cankers. This study demonstrates that virus spread occurs effectively in European chestnut forests and that this biocontrol system is highly dynamic.

  7. An Update on Genetic Resistance of Chickpea to Ascochyta Blight

    Directory of Open Access Journals (Sweden)

    Mamta Sharma

    2016-03-01

    Full Text Available Ascochyta blight (AB caused by Ascochyta rabiei (Pass. Labr. is an important and widespread disease of chickpea (Cicer arietinum L. worldwide. The disease is particularly severe under cool and humid weather conditions. Breeding for host resistance is an efficient means to combat this disease. In this paper, attempts have been made to summarize the progress made in identifying resistance sources, genetics and breeding for resistance, and genetic variation among the pathogen population. The search for resistance to AB in chickpea germplasm, breeding lines and land races using various screening methods has been updated. Importance of the genotype × environment (GE interaction in elucidating the aggressiveness among isolates from different locations and the identification of pathotypes and stable sources of resistance have also been discussed. Current and modern breeding programs for AB resistance based on crossing resistant/multiple resistant and high-yielding cultivars, stability of the breeding lines through multi-location testing and molecular marker-assisted selection method have been discussed. Gene pyramiding and the use of resistant genes present in wild relatives can be useful methods in the future. Identification of additional sources of resistance genes, good characterization of the host–pathogen system, and identification of molecular markers linked to resistance genes are suggested as the key areas for future study.

  8. Mapping of the S. demissum late blight resistance gene R8 to a new locus on chromosome IX

    NARCIS (Netherlands)

    Jo, K.R.; Arens, M.J.B.; Kim, T.Y.; Jongsma, M.A.; Visser, R.G.F.; Jacobsen, E.; Vossen, J.H.

    2011-01-01

    The use of resistant varieties is an important tool in the management of late blight, which threatens potato production worldwide. Clone MaR8 from the Mastenbroek differential set has strong resistance to Phytophthora infestans, the causal agent of late blight. The F1 progeny of a cross between the

  9. Competitive Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-Spectrum Late Blight Resistance

    Science.gov (United States)

    Potato late blight is a particularly destructive plant disease caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary. Late blight has remained particularly problematic despite intensive breeding efforts to integrate resistance into cultivated potato. This is due to the pathogen’s ab...

  10. Efficacy of fungicides on the progress of early blight and yield of potato in Cameroon

    Directory of Open Access Journals (Sweden)

    Fontera, DA.

    1992-01-01

    Full Text Available Five fungicides were evaluated during the 1990 and 1991 growing seasons in two locations in Cameroon for efficacy on the progress of early blight and yield of potato. Disease-progress curves fitted the logistic transformation better than the Gompertz. Fungicidal treatments reduced the rate of early blight progress and area under disease-progress curve (AUDPC. Early blight was more severe in the 1991 season and yields recorded in this season were lower than those in 1990. In both seasons, high yields were obtained in plots receiving six sprays maneb or mancozeb. Two sprays of Ridomil plus (12 % metalaxyl + 60 % cuprous oxide and six of cupric hydroxide also produced appreciable yields, while fosetyl-AI (three sprays provided the least yield increase. Yield losses in non-sprayed plots were estimated at 15.7-53.6 %. Yields were negatively correlated to AUDPC.

  11. Quantification of lateral heterogeneity in carbohydrate permeability of isolated plant leaf cuticles

    NARCIS (Netherlands)

    Remus-Emsermann, M.N.P.; De Oliveira, S.; Schreiber, L.; Leveau, J.H.J.

    2011-01-01

    In phyllosphere microbiology, the distribution of resources available to bacterial colonizers of leaf surfaces is generally understood to be very heterogeneous. However, there is little quantitative understanding of the mechanisms that underlie this heterogeneity. Here, we tested the hypothesis that

  12. Relationship between soil cellulolytic activity and suppression of seedling blight of barley in arable soils

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Knudsen, I.; Elmholt, S.;

    2002-01-01

    The objective was to investigate the relationship between soil suppression of seedling blight of barley caused by Fusarium culmorum (W.G. Smith) Sacc. and the soil cellulolytic activity of beta-glucosidase, cellobiohydrolase and endocellulase. Disease suppression was investigated in bioassays....... From the preliminary results obtained, it is proposed that the cellulolytic activity can be used as an enzymatic approach to study the microbial turnover of organic matter in soils and as indicator of seedling blight of barley caused by F. culmorum. (C) 2002 Elsevier Science B.V. All rights reserved....

  13. Survival of Fusarium graminearum, the causal agent of Fusarium head blight. A review

    OpenAIRE

    Leplat, Johann; Friberg, Hanna; Abid, Muhammad; Steinberg, Christian

    2013-01-01

    Wheat is one of the most cultivated crops worldwide. In 2010, 20 % of wheat and durum wheat were cultivated in Europe, 17 % in China and 9 % in Russia and in North America. Wheat yield can be highly decreased by several factors. In particular Fusarium graminearum Schwabe is a worldwide fungal pest impacting wheat production. F. graminearum is the causal agent of Fusarium head blight, root and stem-base rot of cereals. Losses caused by Fusarium head blight in Northern and Central America from ...

  14. 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.

  15. 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%.

  16. Studies on the control of ascochyta blight in field peas (Pisum sativum L. caused by Ascochyta pinodes in Zhejiang Province, China

    Directory of Open Access Journals (Sweden)

    Na eLiu

    2016-04-01

    Full Text Available Ascochyta blight, an infection caused by a complex of Ascochyta pinodes, Ascochyta pinodella, Ascochyta pisi, and/or Phoma koolunga, is a destructive disease in many field peas (Pisum sativum L.-growing regions, and it causes significant losses in grain yield. To understand the composition of fungi associated with this disease in Zhejiang Province, China, a total of 65 single-pycnidiospore fungal isolates were obtained from diseased pea samples collected from 5 locations in this region. These isolates were identified as Ascochyta pinodes by molecular techniques and their morphological and physiological characteristics. The mycelia of ZJ-1 could penetrate pea leaves across the stomas, and formed specific penetration structures and directly pierced leaves. The resistance level of 23 available pea cultivars was tested against their representative isolate A. pinodes ZJ-1 using the excised leaf-assay technique. The ZJ-1 mycelia could penetrate the leaves of all tested cultivars, and they developed typical symptoms, which suggested that all tested cultivars were susceptible to the fungus. Chemical fungicides and biological control agents were screened for management of this disease, and their efficacies were further determined. Most of the tested fungicides (11 out of 14 showed high activity towards ZJ-1 with EC50 < 5 μg/mL. Moreover, fungicides, including tebuconazole, boscalid, iprodione, carbendazim and fludioxonil, displayed more than 80% disease control efficacy under the recorded conditions. Three biocontrol strains of Bacillus sp. and one of Pantoea agglomerans were isolated from pea-related niches and significantly reduced the severity of disease under greenhouse and field conditions. To our knowledge, this is the first study on ascochyta blight in field peas, and results presented here will be useful for controlling the disease in this area.

  17. Studies on the Control of Ascochyta Blight in Field Peas (Pisum sativum L.) Caused by Ascochyta pinodes in Zhejiang Province, China.

    Science.gov (United States)

    Liu, Na; Xu, Shengchun; Yao, Xiefeng; Zhang, Guwen; Mao, Weihua; Hu, Qizan; Feng, Zhijuan; Gong, Yaming

    2016-01-01

    Ascochyta blight, an infection caused by a complex of Ascochyta pinodes, Ascochyta pinodella, Ascochyta pisi, and/or Phoma koolunga, is a destructive disease in many field peas (Pisum sativum L.)-growing regions, and it causes significant losses in grain yield. To understand the composition of fungi associated with this disease in Zhejiang Province, China, a total of 65 single-pycnidiospore fungal isolates were obtained from diseased pea samples collected from 5 locations in this region. These isolates were identified as Ascochyta pinodes by molecular techniques and their morphological and physiological characteristics. The mycelia of ZJ-1 could penetrate pea leaves across the stomas, and formed specific penetration structures and directly pierced leaves. The resistance level of 23 available pea cultivars was tested against their representative isolate A. pinodes ZJ-1 using the excised leaf-assay technique. The ZJ-1 mycelia could penetrate the leaves of all tested cultivars, and they developed typical symptoms, which suggested that all tested cultivars were susceptible to the fungus. Chemical fungicides and biological control agents were screened for management of this disease, and their efficacies were further determined. Most of the tested fungicides (11 out of 14) showed high activity toward ZJ-1 with EC50 control efficacy under the recorded conditions. Three biocontrol strains of Bacillus sp. and one of Pantoea agglomerans were isolated from pea-related niches and significantly reduced the severity of disease under greenhouse and field conditions. To our knowledge, this is the first study on ascochyta blight in field peas, and results presented here will be useful for controlling the disease in this area. PMID:27148177

  18. EFFECTS OF LATE BLIGHT RESISTANT POTATO CONTAINING RB GENE ON THE SOIL MICROBES, PESTS AND PLANT DISEASES

    Directory of Open Access Journals (Sweden)

    Eny Ida Riyanti

    2014-10-01

    Full Text Available Late blight caused by Phytophthora infestans is an important disease on potato.  Several potato hybrids have been generated by crossing local varieties (Atlantic and Granola with Katahdin SP951 which contains late blight resistance gene RB.  Prior to release, these hybrids need to be evaluated for their environ-mental effects on non-target organisms and natural pests and diseases. The objectives of the study were to investigate the effect of LBR potato hybrids on beneficial soil microbes, pests and diseases. The trial was conducted in the confined field trial (CFT in Lembang, West Java. The parental non-transgenic (NT clones (Granola, Atlantic and Katahdin and LBR hybrids (four clones of Atlantic x Katahdin SP951 hybrids; 10 clones of Granola x Katahdin SP951 were planted at a plant spacing of 30 cm x 70 cm. Fungicide applications were used as treat-ments (no spray, five and twenty times sprays. The experi-ment was arranged in a randomized completely block design with three replications. The parameters determined were popula-tions of N2 fixing and P solubilizing bacteria, soil C/N ratio as well as natural pests and diseases. The results showed that the transgenic LBR potato hybrids did not have negative effect on N fixing bacteria. The bacterial populations were around 1010-11 cells g-1 soil before planting, 1012 cells at 1.5 months after planting (MAP and 108 cells after harvest. For P- solubilizing bacteria, their populations were 1010 cells before planting, 1012 cells at 1.5 MAP and 1011 cells g-1  soil after harvest. The soil C/N ratio of the transgenic plot was not statistically different compared to non-transgenic plot, i.e. 12-15 before planting, 10-11 at 1.5 MAP, and 10 after harvest in non-spray plot. Pests and diseases such as Alternaria solani, Liriomyza, potato tubber moth, aphid and mites on the transgenic and non-transgenic plots were statistically not different. The resistance score for A. solani was 7.2 (parental tansgenic and

  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. 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.

  1. R gene stacking by trans- and cisgenesis to achieve durable late blight resistance in potato

    NARCIS (Netherlands)

    Zhu, S.

    2014-01-01

    Among the many diseases of potato (Solanum tuberosum L.), which is the third food crop in the world after wheat and rice, late blight caused by the oomycete pathogen Phytophthora infestans, is one of the most serious diseases. In the last century, major resistance (R) genes were introgressed mainly

  2. Bringing Benefits and Warding off Blights in Due Commandment (Analytic Study Compared with the Jordanian Law)

    Science.gov (United States)

    Al Etoum, Niebal Mohd Ibrahim; Mowafi, Hanan Sami Mohammad; Al Zubaidi, Faraj Hamad Salem

    2016-01-01

    The study aims to highlight the benefits and blights of the due commandment (intestate law) under Jordanian law for the year (2010) in the article (279). The study came in two sections, the first one dealt with the concept of due commandment, its legitimacy, verdict and terms; in the second section, I've dealt with the persons entitled to due…

  3. Unveiling and deploying durability of late blight resistance in potato : from natural stacking to cisgenic stacking

    NARCIS (Netherlands)

    Kwang-Ryong Jo,

    2013-01-01

    The potato, which receives an increased attention as a food crop, has long been in threats from the oomycete Phytophthora infestans, the causal agent of late blight. This disease still remains the most important constraint in potato producing regions of the world. It might cause the complete destruc

  4. Efficacy of different fungicides against Rhizoctonia brown patch and Pythium blight on turfgrass in Italy.

    Science.gov (United States)

    Mocioni, M; Titone, P; Garibaldi, A; Gullino, M L

    2003-01-01

    Brown patch, incited by Rhizoctonia solani Kuhn, and Pythium blight, caused by Pythium spp. are two of the diseases most frequently observed on turfgrass in high maintenance stands, as on golf courses. In such conditions the control strategies, based on chemicals, are particularly difficult due to the scarcity of fungicides registered for turf in Italy. The results obtained in experimental trials carried out to evaluate the efficacy of chemical and biological products against brown patch and Pythium blight are reported. On mature turfgrass, maintained under fairway conditions, azoxystrobin, and trifoxystrobin, not yet registered on turf, were very effective against brown patch. Tebuconazole, applied in three different formulations, was very effective against R. solani, while Trichoderma spp. and azadiractine did not control the pathogen. In greenhouse conditions on Agrostis stolonifera, in the presence of severe disease incidence, due to artificial inoculation, benalaxyl-M satisfactorily controlled Pythium blight; Trichoderma spp. as well as a commercial formulation of T. harzianum, applied one week before the inoculation, were not effective. Among the fungicides not yet registered for use on turfgrass in Italy, metalaxyl-M + mancozeb was effective against Pythium blight. PMID:15151284

  5. Genetic diversity of rice sheath blight isolates (Rhizoctonia solani AG-1 IA) from different rice cultivars

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Rhizoctonia solani AG 1 IA, the non specific, soil borne, and plant casual agent of rice sheath blight, occurring world widely in rice fields, has become a major disease to rice. In this study,relationships among R. solani AG 1 IA isolates, collected from different rice cultivars were reported.

  6. Fire blight in different production systems in Germany and strategies to control the disease

    OpenAIRE

    Jelkmann, Wilhelm

    2004-01-01

    Fire blight, caused by the bacterium Erwinia amylovora, is a serious disease of pome fruits in many countries of the world. The disease was first recognized at the end of the 18th century in the USA. Its first occurence in Europe was reported in 1957 from England.

  7. Evaluation of Commercial Watermelon Rootstocks for Tolerance to Phytophthora Blight and Watermelon Vine Decline

    Science.gov (United States)

    Phytophthora blight and fruit rot caused by Phytophthora capsici, and watermelon vine decline (WVD) caused by Squash vein yellowing virus (SqVYV), are two important and emerging diseases of watermelons (Citrullus lanatus). Recently, the practice of grafting seedless watermelons (triploids) onto roo...

  8. Multiple minor QTLs are responsible for Fusarium head blight resistance in Chinese wheat landrace Haiyanzhong

    Science.gov (United States)

    Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is a devastatingve disease in wheat (Triticum aestivum L.). Use of host resistance is one of the most effective strategies to minimize the disease damage. Haiyanzhong (HYZ) is a Chinese wheat landrace that shows a high level of resi...

  9. Introduction of Several Methods to Control Fusarium Head Blight(FHB)

    Institute of Scientific and Technical Information of China (English)

    张荣; 张敏

    2008-01-01

    Abstract:Fusariam head blight(FHB)is a worldwide destructive disease of wheat in the warm,semi-humid or humid regions,especially serious in China.The disease not only causes significant losses in yield and re duces grain quanlity,but also induces toxin to contaminated seeds,which is harmful to the healthy of human and livestocks,So it is important to control it.There are several methods to control Fusarium head blight (FHB).Such as using Crop rotation,Soil cultivation and Fertiliser,biological control,Fungicides control, transgenes,resistance to control Fusarium head blight(FHB).All of these methods gain some effect,but also exist their deficiency.Sometimes crop rotation had no significant effect on DON contamination of wheat grain,subsequent reductions in DON contamination were inconsistent when using Soil cultivation and Fer tiliser,Unfortunately,under field conditions,the biological control achieved has been shown to be variable and in some tests has failed to give any control,The use of fungicides,however,have not been consistently effective in controlling FHB and in reducing DON formation,transgene-silencing at different generations is a problem to use transgenes,Information on location of QTL for FHB resistance should improve dramatically in the near future on resistance to control Fusarium head blight(FHB).Therefore,it is pressing to improve control methods,especially to DON.

  10. Population genomics of Fusarium graminearum head blight pathogens in North America

    Science.gov (United States)

    In this study we utilized comparative genomics to identify candidate adaptive alleles in the fungus Fusarium graminearum, the primary pathogen of Fusarium head blight (FHB) in cereal crops. Recent epidemics of FHB have been economically devastating to agriculture, as F. graminearum reduces cereal yi...

  11. Validation of Fusarium head blight resistance QTL using the NC-Neuse / Bess doubled haploid population

    Science.gov (United States)

    Fusarium Head Blight (FHB) is one of the most damaging diseases of wheat. It lowers the grain yield and quality, and contaminates grain with the mycotoxin deoxynivalenol (DON). Genetic resistance is a critical control measure and breeding objective. Many studies have focused on the genetic basis of ...

  12. Action and reaction of host and pathogen during Fusarium head blight disease

    DEFF Research Database (Denmark)

    Walter, Stephanie; Nicholson, Paul; Doohan, Fiona M

    2010-01-01

    The Fusarium species Fusarium graminearum and Fusarium culmorum, Which are responsible for Fusarium head blight (FHB) disease, reduced world-wide cereal crop yield and, as a consequence of their mycotoxin production in cereal grain, impact on both human and animal health. Their study is greatly...

  13. Investigation of the effect of nitrogen on severity of Fusarium Head Blight in barley

    DEFF Research Database (Denmark)

    Yang, Fen; Jensen, J.D.; Spliid, N.H.;

    2010-01-01

    The effect of nitrogen on Fusarium Head Blight (FHB) in a susceptible barley cultivar was investigated using gel-based proteomics. Barley grown with either 15 or 100 kg ha(-1)N fertilizer was inoculated with Fusarium graminearum (Fg). The storage protein fraction did not change significantly...

  14. Impact of new populations of Phytophthora infestans on integrated late blight management

    NARCIS (Netherlands)

    Flier, W.G.; Kessel, G.J.T.; Bosch, van den G.B.M.; Turkensteen, L.J.

    2002-01-01

    A recent migration of a variable population of P. infestans has largely displaced the clonal A1 population in Western Europe. Sexual reproduction in European late blight populations is now possible and has been reported. The increased levels of aggressiveness form an important epidemiological featur

  15. Introgression and genetic characterization of alien Fusarium head blight resistance in wheat

    Science.gov (United States)

    Alien species are an important source of genetic variability in wheat (Triticum spp.) and carry genes for resistance to numerous pathogens, including Fusarium graminearum Schwabe, the causal agent of Fusarium head blight (FHB). The goal of this project was to develop breeder-friendly, FHB-resistant ...

  16. Elevated [CO2] compromises both Type I and Type II wheat resistance to Fusarium head blight

    Science.gov (United States)

    Fusarium head blight (FHB) is one of the world’s most devastating wheat diseases, and results in significant yield loss and contamination of grain with harmful mycotoxins called trichothecenes. Despite emerging risks of increased mycotoxin contamination in food and feed associated with climate chang...

  17. The potato late blight pathogen Phytophthora infestans and other pathogenic oomycota

    NARCIS (Netherlands)

    Govers, F.; Drenth, A.; Pieterse, C.M.J.

    1997-01-01

    Potato late blight, caused by a member of the Oomycota, Phytophthora infestans (Mont.) De Bary, is one of the most important and devastating diseases of potato (Solanum tuberosum). The pathogen attacks both foliage and tubers, and spreads rapidly through host tissues, thereby causing a destructive n

  18. Durable Late Blight Resistance in Potato Through Dynamic Varieties Obtained by Cisgenesis

    NARCIS (Netherlands)

    Haverkort, A.J.; Boonekamp, P.M.; Hutten, R.; Jacobsen, E.; Lotz, L.A.P.; Kessel, G.J.T.; Vossen, J.H.; Visser, R.G.F.

    2016-01-01

    From 2006 through 2015, a research project on Durable Resistance in potato against Phytophthora (DuRPh) was carried out at Wageningen University and Research Centre. Its objective was to develop a proof of principle for durable resistance against late blight by cisgenesis. This public-funded proj

  19. Fusarium head blight resistance in wheat using the in vitro androgenic approach.

    NARCIS (Netherlands)

    Bruins, M.B.M.

    1998-01-01

    Wheat ( Triticum aestivum L.) belongs to the three most important food crops in the world. In certain years, the crop can suffer considerable damage as a result of Fusarium Head Blight (FHB), especially as no chemical control is effective against this disease. This disease is mainly caused by the fu

  20. The role of oospores in the epidemiology of potato late blight

    NARCIS (Netherlands)

    Kessel, G.J.T.; Andersson, B.; Widmark, A.K.; Yuen, J.E.; Evenhuis, A.; Turkensteen, L.J.; Lehtinen, A.; Nielsen, B.; Ravnskov, S.; Hansen, J.G.; Hermansen, A.; Brurberg, M.B.; Nordskog, B.

    2009-01-01

    Potato late blight (Phytophthora infestans) is a plant disease feared globally by farmers and the potato industry. P. infestans is a heterothallic oomycete with two mating types. Until recently the pathogen was limited to surviving between seasons as living mycelia in its host plant in most parts of

  1. Fusarium spp. associated with head blight of wheat in South Africa

    Science.gov (United States)

    Fusarium head blight (FHB) of wheat is caused by numerous Fusarium species, including trichothecene-producers. In South Africa, FHB is mostly associated with irrigated wheat rotated with maize. Twenty symptomatic wheat heads were collected from four cultivars each in irrigated fields in the Northern...

  2. Results of potato late blight demonstrations in Garut and Pangalengan, Indonesia, October 2014-January 2015

    NARCIS (Netherlands)

    Schepers, H.T.A.M.; Gunadi, N.; Putter, de H.; Moekasan, T.K.; Prabaningrum, L.; Karjadi, A.K.

    2015-01-01

    Demo plots with potato varieties Atlantic and Granola were laid out in Garut and Pangalengan from October 2014 to January 2015. The objective of the demo plots described in this report are to investigate the influence of three factors on the efficacy of three factors in late blight control strategie

  3. Pantoea applied genomics to understand and improve biocontrol activity against fire blight

    Science.gov (United States)

    Pantoea agglomerans and P. vagans (ex. Erwinia herbicola) are common epiphytes of pome fruit flowers and three strains (E325, P10c, C9-1) have been commercially developed as effective biocontrol products for managing fire blight (Erwinia amylovora). Antibiotics as a standard, reliable chemical optio...

  4. [Erwinia amylovora--the fire blight pathogen of trees in Ukraine].

    Science.gov (United States)

    Iakovleva, L M; Moroz, S N; Shcherbina, T N; Ogorodnik, L E; Gvozdiak, R I; Patyka, V F

    2014-01-01

    Niduses of fire blight of fruit and ornamental trees have been found in the Kyiv and Vinnitsa regions of Ukraine. Pathogen Erwinia amylovora was isolated between April and October. The pathogen was often accompanied by bacteria Pseudomonas syringae pv. syringae. Artificial infection with a mixture of bacteria E. amylovora and P. syringae pv. syringae accelerates and enhances the disease process in the laboratory.

  5. Leaf spring, and electromagnetic actuator provided with a leaf spring

    OpenAIRE

    Berkhoff, Arthur Perry; Lemmen, Remco Louis Christiaan

    2002-01-01

    The invention relates to a leaf spring for an electromagnetic actuator and to such an electromagnetic actuator. The leaf spring is formed as a whole from a disc of plate-shaped, resilient material. The leaf spring comprises a central fastening part, an outer fastening part extending therearound and at least two leaf spring arms extending between the central and outer fastening part. Viewed from the central fastening part, the leaf spring arms (23) have a first zone (24) originating from the c...

  6. 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.

  7. 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. PMID:27178300

  8. Bacterial Vaginosis

    Science.gov (United States)

    ... 586. Related Content STDs during Pregnancy Fact Sheet Pregnancy and HIV, Viral Hepatitis, and STD Prevention Pelvic Inflammatory Disease ( ... Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ... STDs See Also Pregnancy Reproductive ...

  9. Bacterial Meningitis

    Science.gov (United States)

    ... Schedules Preteen & Teen Vaccines Meningococcal Disease Sepsis Bacterial Meningitis Recommend on Facebook Tweet Share Compartir On this ... serious disease. Laboratory Methods for the Diagnosis of Meningitis This manual summarizes laboratory methods used to isolate, ...

  10. 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

  11. 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

  12. Control of seedling blight in winter wheat by seed treatments - impact on emergence, crop stand, yield and deoxynivalenol

    DEFF Research Database (Denmark)

    Jørgensen, Lise N; K. Nielsen, Linda; Nielsen, Bent J

    2012-01-01

    Seedling blight caused by Fusarium spp. and Microdochium spp. is common on wheat grain, and severe attacks can lead to poor establishment of new crops. Several seed treatments using bitertanol, difenoconazole, triticonazole, maneb, fludioxonil or guazatine found to significantly control Fusarium...... seedling blight (Fusarium spp., Microdochium spp.) were improving germination and reducing seedling blight on roots and coleoptiles under field conditions in winter wheat. Some of the seed treatments were also shown to have an impact on soil-borne Fusarium in trials carried out under glasshouse conditions...... germination by approximately 100%, which led to an improved crop stand and yield increases in the range of 1.2–1.5 tonnes ha−1. Attacks of Fusarium head blight were relatively slight in the two trials and the content of deoxynivalenol was below the EU limits of 1250 ppb in the harvested grain. Even so, seed...

  13. 草坪草叶枯病病原鉴定%Identification of Leaf Blight Pathogen on Turfgrass

    Institute of Scientific and Technical Information of China (English)

    徐秉良; 王吉霞

    2002-01-01

    从典型叶枯病病斑中分离出3种病原茵,经对其病原茵形态、培养性状和致病性等方面的测定表明,兰州市草坪草叶枯病主要致病茵为禾草离蠕孢(成polaris 5arokiniaha),其次为狗牙根离蠕孢(B.cynodontis).禾草离蠕孢茵在不同品种草坪草中的潜育期不同,在感病品种ReblⅡ中的潜育期为36h,在抗病品种Raymond中的潜育期为72 h.

  14. Population structure of Cercospora kikuchii, the causal agent of Cercospora leaf blight and purple seed stain in soybean.

    Science.gov (United States)

    Cai, G; Schneider, R W

    2008-07-01

    Random amplified polymorphic DNA (RAPD) and microsatellite-primed polymerase chain reaction (MP-PCR) were used to characterize 164 isolates of Cercospora kikuchii, most of which were collected from Louisiana. Plant tissue (seeds versus leaves), but not host cultivar, had a significant impact on pathogen population differentiation. Cluster analysis showed that the Louisiana population was dominated by a primary lineage (group I) with only a few Louisiana isolates belonging to the minor lineage that also included the non-Louisiana isolates (group II). A previous study showed that isolates could be differentiated according to vegetative compatibility groups (VCGs). However, RAPD and MP-PCR data demonstrated that isolates of C. kikuchii were not generally clustered according to these VCGs. Furthermore, genetic relationships within and between VCGs were examined using sequences of the intergenic spacer region of rDNA. These analyses showed that VCG is not an indicator of evolutionary lineage in this fungus. Our results suggest the likely existence of a cryptically functioning sexual stage in some portion of the C. kikuchii population.

  15. Biosynthesis of the antimetabolite 6-thioguanine in Erwinia amylovora plays a key role in fire blight pathogenesis.

    Science.gov (United States)

    Coyne, Sébastien; Chizzali, Cornelia; Khalil, Mohammed N A; Litomska, Agnieszka; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

    2013-09-27

    Sulfur for fire: The molecular basis for the biosynthesis of the antimetabolite 6-thioguanine (6TG) was unveiled in Erwinia amylovora, the causative agent of fire blight. Bioinformatics, heterologous pathway reconstitution in E. coli, and mutational analyses indicate that the protein YcfA mediates guanine thionation in analogy to 2-thiouridylase. Assays in planta and in cell cultures reveal for the first time a crucial role of 6TG in fire blight pathogenesis.

  16. Bacterial carbonatogenesis

    International Nuclear Information System (INIS)

    Several series of experiments in the laboratory as well as in natural conditions teach that the production of carbonate particles by heterotrophic bacteria follows different ways. The 'passive' carbonatogenesis is generated by modifications of the medium that lead to the accumulation of carbonate and bicarbonate ions and to the precipitation of solid particles. The 'active' carbonatogenesis is independent of the metabolic pathways. The carbonate particles are produced by ionic exchanges through the cell membrane following still poorly known mechanisms. Carbonatogenesis appears to be the response of heterotrophic bacterial communities to an enrichment of the milieu in organic matter. The active carbonatogenesis seems to start first. It is followed by the passive one which induces the growth of initially produced particles. The yield of heterotrophic bacterial carbonatogenesis and the amounts of solid carbonates production by bacteria are potentially very high as compared to autotrophic or chemical sedimentation from marine, paralic or continental waters. Furthermore, the bacterial processes are environmentally very ubiquitous; they just require organic matter enrichment. Thus, apart from purely evaporite and autotrophic ones, all Ca and/or Mg carbonates must be considered as from heterotrophic bacterial origin. By the way, the carbon of carbonates comes from primary organic matter. Such considerations ask questions about some interpretations from isotopic data on carbonates. Finally, bacterial heterotrophic carbonatogenesis appears as a fundamental phase in the relationships between atmosphere and lithosphere and in the geo-biological evolution of Earth. (author)

  17. Characterization of tomato accessions for resistance to early blight

    Directory of Open Access Journals (Sweden)

    José Fernando Jurca Grigolli

    2011-01-01

    Full Text Available The purpose of this study was to characterize 50 tomato genotypes of the Vegetable Genebank of the FederalUniversity of Viçosa. They were evaluated together with the controls Débora, Fanny and Santa Clara, in a randomized block designwith two replications. The experiment was conducted in a research field of the UFV, from February to May 2007. We evaluated thedisease severity, which is the percentage of diseased leaf area. The severity values were transformed into area under the diseaseprogress curve (AUDPC, improving the result visualization. The analysis of variance and grouping of AUDPC means by the Scott-Knott test at 5 % significance were performed. The accessions BGH-2081, BGH-2034, BGH-700, BGH-2057, BGH-2035, BGH-2054, BGH-2018, BGH-2065, BGH-2008, and BGH-2032 had a lower mean AUDPC than the controls and are therefore indicatedfor future breeding programs.

  18. 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.

  19. Genetic characterization of the HrpL regulon of the fire blight pathogen Erwinia amylovora reveals novel virulence factors.

    Science.gov (United States)

    McNally, R Ryan; Toth, Ian K; Cock, Peter J A; Pritchard, Leighton; Hedley, Pete E; Morris, Jenny A; Zhao, Youfu; Sundin, George W

    2012-02-01

    The bacterial pathogen Erwinia amylovora is the causal agent of fire blight, an economically significant disease of apple and pear. Disease initiation by E. amylovora requires the translocation of effector proteins into host cells via the hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS). The alternative sigma factor HrpL positively regulates the transcription of structural and translocated components of the T3SS via hrp promoter elements. To characterize genome-wide HrpL-dependent gene expression in E. amylovora Ea1189, wild-type and Ea1189ΔhrpL strains were cultured in hrp-inducing minimal medium, and total RNA was compared using a custom microarray designed to represent the annotated genes of E. amylovora ATCC 49946. The results revealed 24 genes differentially regulated in Ea1189ΔhrpL relative to Ea1189 with fold-change expression ratios greater than 1.5; of these, 19 genes exhibited decreased transcript abundance and five genes showed increased transcript abundance relative to Ea1189. To expand our understanding of the HrpL regulon and to elucidate direct versus indirect HrpL-mediated effects on gene expression, the genome of E. amylovora ATCC 49946 was examined in silico using a hidden Markov model assembled from known Erwinia spp. hrp promoters. This technique identified 15 putative type III novel hrp promoters, seven of which were validated with quantitative polymerase chain reaction based on expression analyses. It was found that HrpL-regulated genes encode all known components of the hrp T3SS, as well as five putative type III effectors. Eight genes displayed apparent indirect HrpL regulation, suggesting that the HrpL regulon is connected to downstream signalling networks. The construction of deletion mutants of three novel HrpL-regulated genes resulted in the identification of additional virulence factors as well as mutants displaying abnormal motility and biofilm phenotypes. PMID:21831138

  20. Leaf spring, and electromagnetic actuator provided with a leaf spring

    NARCIS (Netherlands)

    Berkhoff, Arthur Perry; Lemmen, Remco Louis Christiaan

    2002-01-01

    The invention relates to a leaf spring for an electromagnetic actuator and to such an electromagnetic actuator. The leaf spring is formed as a whole from a disc of plate-shaped, resilient material. The leaf spring comprises a central fastening part, an outer fastening part extending therearound and

  1. [The sugar cane blight of the 1860s: science applied to agriculture].

    Science.gov (United States)

    Bediaga, Begonha

    2012-12-01

    The Imperial Instituto Fluminense de Cultura (Fluminense Imperial Institute of Agriculture) encouraged debate with a view to eradicating the blight that devastated sugar cane plantations in the State of Bahia. Rural landowners, government officials and men of science participated in the discussions. The article presents the context of the sciences applied to agriculture, especially agricultural chemistry and the repercussions of the 'discoveries' of Justus Liebig in Brazil. The debate at the Imperial Instituto about the sugar cane blight was analyzed, together with the ideas espoused there and the characters involved in the issue. The procedures and solutions presented are studied, as well as the formation of knowledge networks around the agricultural sciences, which was in the process of institutionalization at the time.

  2. QTL mapping of resistance to sheath blight in maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    YANG Hua; YANG Junpin; RONG Tingzhao; TAN Jun; QIU Zhenggao

    2005-01-01

    The genetic linkage map has been constructed with 125 SSR markers based on BC1:2 population consisting of 322 lines derived from the combination of (CML270×478) ×CML270 in maize (Zea mays L.), covering 1939.0 cM of maize genome. The average mapping distance was about 15.5 cM. Three major QTLs of the relative resistant index of resistance to maize sheath blight (Rhizoctonia solani) had been located on chromosomes 1, 7 by composite interval mapping (CIM). 7 QTLs of the plant height have been located on chromosomes 3, 4, 5, 6. Five QTLs of ear height have been located on chromosomes 3, 4, 6. The resistance to the sheath blight is shown to be not relative to plant height and ear height genetically. Inbred line CML270 was used for molecular assisted selection and cloning the genes.

  3. Reduction of Fusarium head blight and deoxynivalenol in wheat with early fungicide applications of prothioconazole

    OpenAIRE

    Edwards, Simon G; Godley, Nigel

    2010-01-01

    Abstract Numerous studies have identified the benefit of fungicides applied at flowering (Zadoks Growth Stage (GS) 59-69) in the reduction of Fusarium head blight (FHB) and the reduction of deoxynivalenol (DON) in harvested wheat grain. Two experiments were performed to identify the ability of prothioconazole (Proline?, Bayer CropScience) at three timings to reduce FHB and resulting DON in harvested grain of wheat. Prothioconazole (150 g ha-1) was applied to plots of wheat at GS3...

  4. PHYSICAL, MORPHOLOGICAL PROPERTIES AND RAMAN SPECTROSCOPY OF CHESTNUT BLIGHT DISEASED CASTANEA SATIVA MILL. WOOD

    OpenAIRE

    Gokhan Gunduz,; Mehmet Ali Oral; Mehmet Akyuz; Deniz Aydemir; Barbaros Yaman; Nejla Asik; Ali Savas Bulbul; Surhay Allahverdiyev

    2016-01-01

    In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD) wood were investigated, and the study also included observations using Raman spectroscopy. The objective of these investigations was to determine the extent of the damage that is done to the wood of the diseased chestnut trees, which must be removed from the forest and used in the manufacture of industrial products. It was indicated that most of the adverse effects of the disease were in the vascu...

  5. Non-conventional possibilities of protection of apple and pear against fire blight (Erwinia amylovora)

    OpenAIRE

    Piotr Sobiczewski; Grzegorz Krupiński; Joanna Puławska

    2013-01-01

    Standard program of plant protection against fire blight consists of use of management practices and chemical control method. Recently a new, non-conventional possibilities based on application of biocontrol agents (two biopreparations have been already introduced into practice: Bliteban A506 (Pseudomonas fluorescens) and BlossomBless (Pantoea agglomerans), plant extracts active against Erwinia amylovora (AkseBio containing extracts from Thymbra spicata and Biomit Plussz with extracts from va...

  6. TWIG BLIGHT AND DEFOLIATION CAUSED BY Colletotrichum horii IN PERSIMMONS IN BRAZIL

    Directory of Open Access Journals (Sweden)

    LOUISE LARISSA MAY DE MIO

    2015-03-01

    Full Text Available Persimmon anthracnose has been a great concern to Brazilian producers. This study aimed to identify and characterized the causal species from Brazilian persimmons byassessing morphological and molecular characteristics and pathogenicity tests. Five fungal isolatesobtained from diseased twigs and fruits were identified as Colletotrichum horii, based on morphologicalcharacteristics and nucleotide sequences of ITS region. Inoculation tests revealed that the fungal isolates caused necrotic spots followed by defoliation of leaves, blight of twigs and buds of potted persimmon plants.

  7. Survival potential of Phytophthora infestans sporangia in relation to environmental factors and late blight occurrence

    Directory of Open Access Journals (Sweden)

    Modesto Olanya Ocen

    2016-01-01

    Full Text Available Potato is an important crop globally and late blight (Phytophthora infestans often results in severe crop loss. The cost for late blight control can be in excess of $210 million in the United States. We utilised a non-parametric density distribution analysis of local temperature (T and relative humidity (RH, from 2005 to 2009, to assess and validate sporangia survival potential using survival model and late blight risks during the potato cropping season at Presque Isle, in the northern part of the state of Maine, USA. Modelbased analyses showed that ambient temperatures of 3−30°C and RH values of 45−100% were conducive for sporangia survival. Disease outbreaks and risk periods coincided with a high sporangia survival probability (15−35%. Due to the omission of solar radiation (SR in the computation of survival potential in previous research, we applied a Cox proportional model to estimate the probability of sporangia survival [i.e. hazard at a specific time H(t] as a function of baseline hazard (H0 and the influencing parameters. The model is: H(t = H0(t × exp(0.067ET + 0.138T + 0.083RH + 0.001SR where ET is exposure time. The survival model indicated that RH (β = 0.083 and T (β = 0.138 were significant (p < 0.05 factors in sporangia survival in comparison to SR (β = 0.001. The hazard ratio, indicative of sporangia survival risk, varied with the predictors. For the unit increase of T, sporangia survival hazard increased by 1.148 times. The Cox model and sporangia hazard probabilities can be used for short-term disease forecasts based on the risk period most conducive for pathogen survival and targeted fungicide applications for optimum late blight management.

  8. Controlling Foliar Blight of Wheat in South Asia: A Holistic Approach

    OpenAIRE

    Duveiller, E.; Sharma, R.C.; MERCADO, D.; MARAITE, H.; BHATTA, M. R.; Ortiz-Ferrara, G.; Sharma, D.

    2005-01-01

    Foliar blight is a major biotic constraint to wheat in the Gangetic plains of south Asia, particularly in the rice-wheat system. The disease occurs as a complex of spot blotch and tan spot caused by C. sativus and P. tritici-repentis, respectively. Yield losses reach on average 15% but are variable depending on sowing time, years, locations and stress conditions. Resistance breeding has been the cornerstone of the control strategy. Through international agricultural research efforts in collab...

  9. Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica.

    OpenAIRE

    Cortesi, P; McCulloch, C.E.; Song, H; H. Lin; Milgroom, M G

    2001-01-01

    Vegetative incompatibility in fungi has long been known to reduce the transmission of viruses between individuals, but the barrier to transmission is incomplete. In replicated laboratory assays, we showed conclusively that the transmission of viruses between individuals of the chestnut blight fungus Cryphonectria parasitica is controlled primarily by vegetative incompatibility (vic) genes. By replicating vic genotypes in independent fungal isolates, we quantified the effect of heteroallelism ...

  10. Role of micronutrients in defense to white rust and Alternaria blight infecting Indian mustard.

    Science.gov (United States)

    Rathi, A S; Singh, Dhiraj; Avtar, Ram; Kumar, Pawan

    2015-03-01

    Field experiments were carried out at Oilseeds Research Area of CCS Haryana Agricultural University, Hisar during rabi, 2008-09 to 2011-12 to find out the possible role of soil application of different micronutrients alone and in combinations in defense to white rust and Alternaria blight diseases in Indian mustard [Brassica juncea (L.) Czern & Coss.]. Among the sole application of micronutrients, minimum disease severity of both white rust (35.0%) and Alternaria blight (31.8%) was observed when S @ 40 kg ha in the form of Gypsum was applied as basal dose in the soil. When Gypsum was supplemented with Borax @10 kg ha(-1) or with ZnSO4 @15 kg ha(-1) the level of tolerance seems to be improved for both the diseases as compared to the sole treatment of each nutrient, i.e., ZnSO4 @ 15 kg/ha, Borax @ 10 kg ha' and Gypsum @ 250 kg ha(-1). Furthermore, minimum disease severity of both white rust (31.3 %) and Alternaria blight (26.3 %) was observed with soil application of ZnSO4 @ 15 kg ha(-1) + Borax @ 10 kg ha(-1) + Gypsum @250 kg ha(-1) as basal dose as compared to the severity of white rust (43.6%) and Alternaria blight (38.6%) in untreated check. Significant increase in seed yield (1612 kg ha(-1)) was also recorded in above mentioned treatment as compared to the yield (1337 kg ha(-1)) in untreated check. These findings will also be helpful in maintaining soil health and minimizing the losses due to both the fungal diseases for eco-friendly sustainability of Indian mustard.

  11. 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...

  12. 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

  13. 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

  14. The Contemporary Situation of Dothistroma Needle Blight Outbreak in the Czech Republic

    Directory of Open Access Journals (Sweden)

    BEDNAROVA, Miroslava

    2007-01-01

    Full Text Available Dothistroma needle blight Mycosphaerella pini E. Rostrup resp. its anamorphic stage Dothistroma septospora (Dorog. Morelet was for the first time noted in the region of the Czech Republic in a consignment of imported plants of Austrian pine Pinus nigra Arnold in 1999. In 2000, it was also found on Pinus nigra in an open planting in a plantation of Christmas trees near the village of Jedovnice by Brno in the South Moravia. In the Czech Republic, Dothistroma needle blight was identified on 19 species of pines and 5 species of spruces. The critical period for infection is in the Czech Republic from the second half of May until the end of June, when the new shoots and needles develop. The incubation period lasts about 2–4 months depending on climatic conditions. The first symptoms on the needles infected in the current year appear in August being clearly expressed from September to November. In the CR, Dothistroma needle blight spread probably with infected planting stock obtained from import at the end of the 80s and at the beginning of the 90s.

  15. 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...... biogeochemical processes are carried exclusively by bacteria. * Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life....

  16. [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. PMID:27474242

  17. Prospect of the QTL-qSB-9Tq utilized in molecular breeding program of japonica rice against sheath blight

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The major QTL-qSB-9Tq conferring partial resistance to rice (Oryza sativa L.) sheath blight (Rhizoctonia solani Kühn) has been verified on chromosome 9 of the indica rice cultivar, Teqing. In this study, the prospect of this QTL utilized in molecular breeding program of japonica rice for sheath blight resistance was investigated. Most of the japonica rice cultivars showed lower level of sheath blight resistance than the indica rice cultivars. At the corresponding site of qSB-9Tq, nine typical japonica rice culfivars from different ecological regions or countries proved to possess the susceptible allele(s). Introgression of qSB-9Tq into these cultivars enhanced their resistance level by decreasing sheath blight score of 1.0 (0.5-1.3), which indicated that qSB-9Tq had a large potential in strengthening the resistance of japonica rice to sheath blight. The use of the three molecular markers, which were polymorphic between Teqing and many japonica rice cultivars, promotes the application of qSB-9Tq in a concrete molecular breeding program.

  18. The Role of Antioxidant Enzymes in Adaptive Responses to Sheath Blight Infestation under Different Fertilization Rates and Hill Densities

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2014-01-01

    Full Text Available Sheath blight of rice, caused by Rhizoctonia solani, is one of the most devastating rice diseases worldwide. No rice cultivar has been found to be completely resistant to this fungus. Identifying antioxidant enzymes activities (activity of superoxide dismutase (SOD, peroxidase (POD, and catalase (CAT and malondialdehyde content (MDA responding to sheath blight infestation is imperative to understand the defensive mechanism systems of rice. In the present study, two inoculation methods (toothpick and agar block method were tested in double-season rice. Toothpick method had greater lesion length than agar block method in late season. A higher MDA content was found under toothpick method compared with agar block method, which led to greater POD and SOD activities. Dense planting caused higher lesion length resulting in a higher MDA content, which also subsequently stimulated higher POD and SOD activity. Sheath blight severity was significantly related to the activity of antioxidant enzyme during both seasons. The present study implies that rice plants possess a system of antioxidant protective enzymes which helps them in adaptation to sheath blight infection stresses. Several agronomic practices, such as rational use of fertilizers and optimum planting density, involved in regulating antioxidant protective enzyme systems can be regarded as promising strategy to suppress the sheath blight development.

  19. 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.

  20. Rpi-vnt1.1, a Tm-2(2) Homolog from Solanum venturii, Confers Resistance to Potato Late Blight

    NARCIS (Netherlands)

    Foster, S.J.; Park, T.H.; Pel, M.; Brigneti, G.; Sliwka, J.; Jagger, L.; Vossen, van der E.A.G.; Jones, J.D.G.

    2009-01-01

    Despite the efforts of breeders and the extensive use of fungicide control measures, late blight still remains a major threat to potato cultivation worldwide. The introduction of genetic resistance into cultivated potato is considered a valuable method to achieve durable resistance to late blight. H

  1. 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

    2014-01-01

    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%. PMID:25146135

  2. Characterization of Anticancer, Antimicrobial, Antioxidant Properties and Chemical Compositions of Peperomia Pellucida Leaf Extract

    OpenAIRE

    Desy Fitrya Syamsumir; Julius Yong Fu Siong; Wendy Wee; Lee Seong Wei

    2011-01-01

    Peperomia pellucida leaf extract was characterized for its anticancer, antimicrobial, antioxidant activities, and chemical compositions. Anticancer activity of P. pellucida leaf extract was determined through Colorimetric MTT (tetrazolium) assay against human breast adenocarcinoma (MCF-7) cell line and the antimicrobial property of the plant extract was revealed by using two-fold broth micro-dilution method against 10 bacterial isolates. Antioxidant activity of the plant extract was then char...

  3. Identification of Secondary Metabolites Compounds and Antibacterial Activities on The Extract of Soursop Leaf

    OpenAIRE

    Dian Riana Ningsih; Zusfahair Zusfahair; Dwi Kartika

    2016-01-01

    Treatment of bacterial infectious diseases using semi-synthetic antibiotics can lead to resistance, so as to overcome it necessary to search for natural ingredients from plant extracts that has potential as an antibacterial, one of which is the leaf extract of soursop (Annona muricata L.). This study aims to determine the antibacterial activity of soursop leaf against E. coli and identify groups most active chemical compounds from the extracts. Soursop leaves extracted by maceration using n-h...

  4. Cladosporium cladosporioides and C. tenuissimum Cause Blossom Blight in Strawberry in Korea.

    Science.gov (United States)

    Nam, Myeong Hyeon; Park, Myung Soo; Kim, Hyun Sook; Kim, Tae Il; Kim, Hong Gi

    2015-09-01

    Blossom blight in strawberry was first observed in a green house in Nonsan, Damyang, and Geochang areas of Korea, between early January to April of 2012. Disease symptoms started as a grey fungus formed on the stigma, which led to the blossom blight and eventually to black rot and necrosis of the entire flower. We isolated the fungi purely from the infected pistils and maintained them on potato dextrose agar (PDA) slants. To test Koch's postulates, we inoculated the fungi and found that all of the isolates caused disease symptoms in the flower of strawberry cultivars (Seolhyang, Maehyang, and Kumhyang). The isolates on PDA had a velvet-like appearance, and their color ranged between olivaceous-brown and smoky-grey to olive and almost black. The intercalary conidia of the isolates were elliptical to limoniform, with sizes ranging from 5.0~10.5 × 2.5~3.0 µm to 4.0~7.5 × 2.0~3.0 µm, respectively. The secondary ramoconidia of these isolates were 0- or 1-septate, with sizes ranging betweem 10.0~15.0 × 2.5~3.7 µm and 8.7~11.2 × 2.5~3.2 µm, respectively. A combined sequence analysis of the internal transcribed spacer regions, partial actin (ACT), and translation elongation factor 1-alpha (TEF) genes revealed that the strawberry isolates belonged to two groups of authentic strains, Cladosporium cladosporioides and C. tenuissimum. Based on these results, we identified the pathogens causing blossom blight in strawberries in Korea as being C. cladosporioides and C. tenuissimum. PMID:26539056

  5. EVALUATION OF TRICHODERMA SPP. ON BEAN CULTURE, IN ANTHRACNOSE, WEB BLIGHT AND ROOT-KNOT NEMATODE

    Directory of Open Access Journals (Sweden)

    P. E. V. Aguiar

    2014-09-01

    Full Text Available Mato Grosso is the third largest producer of bean from Brazil, being the third harvest (irrigated the most productive, but diseases such as anthracnose, web blight and nematodes of galls cause losses to producers. In addition, a measure widely used and little studied for the control of diseases and nematodes in Mato Grosso is the biological control, which consists of the action of other microorganisms on phytopathogens. Thus, the objective of the present study was to evaluate the effect of Trichoderma harzianum and T. asperellum in the development (height of plants, chlorophyll and number of pods of culture of bean, in the control of anthracnose (Colletotrichum lindemuthianum, web blight (Rhizoctonia solani and in the population of Meloidogyne spp. in the soil. The experiment was accomplished in area experimental of University Federal of Mato Grosso/Campus Sinop. The experimental design was of entirely randomized with 12 parcels of 5m² each, with 3 treatments and 4 replications. The cultivar used was Whitey, carioca group, and the seed treatment performed with product Pyraclostrobin + Thiophanate Methyl + Fipronil and after drying of the inoculation of biocontrol agents and manual seeding. It was observed that the application of T. harzianum and T. asperellum, not promoted increase of chlorophyll, height of plants in bean culture, without reducing the population of Meloidogyne spp.. However, biocontrol agents have reduced the severity of anthracnose and web blight and promoted an increase in the average number of plant pods-1. It is therefore concluded that biocontrol agents show potential for application in bean culture in the North of Mato Grosso.

  6. Development of the First Cisgenic Apple with Increased Resistance to Fire Blight.

    Directory of Open Access Journals (Sweden)

    Thomas D Kost

    Full Text Available The generation and selection of novel fire blight resistant apple genotypes would greatly improve the management of this devastating disease, caused by Erwinia amylovora. Such resistant genotypes are currently developed by conventional breeding, but novel breeding technologies including cisgenesis could be an alternative approach. A cisgenic apple line C44.4.146 was regenerated using the cisgene FB_MR5 from wild apple Malus ×robusta 5 (Mr5, and the previously established method involving A. tumefaciens-mediated transformation of the fire blight susceptible cultivar 'Gala Galaxy' using the binary vector p9-Dao-FLPi. The line C44.4.146 was shown to carry only the cisgene FB_MR5, controlled by its native regulatory sequences and no transgenes were detected by PCR or Southern blot following heat induced recombinase-mediated elimination of the selectable markers. Although this line contains up to 452 bp of vector sequences, it still matches the original definition of cisgenesis. A single insertion of T-DNA into the genome of 'Gala Galaxy' in chromosome 16 was identified. Transcription of FB_MR5 in line C44.4.146 was similar to the transcription in classically bred descendants of Mr5. Three independent shoot inoculation experiments with a Mr5 avirulent strain of Erwinia amylovora were performed using scissors or syringe. Significantly lower disease symptoms were detected on shoots of the cisgenic line compared to those of untransformed 'Gala Galaxy'. Despite the fact that the pathogen can overcome this resistance by a single nucleotide mutation, this is, to our knowledge, the first prototype of a cisgenic apple with increased resistance to fire blight.

  7. 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.

  8. Exploring new roles for the rpoS gene in the survival and virulence of the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Santander, Ricardo D; Monte-Serrano, Mercedes; Rodríguez-Herva, José J; López-Solanilla, Emilia; Rodríguez-Palenzuela, Pablo; Biosca, Elena G

    2014-12-01

    Erwinia amylovora causes fire blight in economically important plants of the family Rosaceae. This bacterial pathogen spends part of its life cycle coping with starvation and other fluctuating environmental conditions. In many Gram-negative bacteria, starvation and other stress responses are regulated by the sigma factor RpoS. We obtained an E. amylovora rpoS mutant to explore the role of this gene in starvation responses and its potential implication in other processes not yet studied in this pathogen. Results showed that E. amylovora needs rpoS to develop normal starvation survival and viable but nonculturable (VBNC) responses. Furthermore, this gene contributed to stationary phase cross-protection against oxidative, osmotic, and acid stresses and was essential for cross-protection against heat shock, but nonessential against acid shock. RpoS also mediated regulation of motility, exopolysaccharide synthesis, and virulence in immature loquats, but not in pear plantlets, and contributed to E. amylovora survival in nonhost tissues during incompatible interactions. Our results reveal some unique roles for the rpoS gene in E. amylovora and provide new knowledge on the regulation of different processes related to its ecology, including survival in different environments and virulence in immature fruits.

  9. Discovery of plant phenolic compounds that act as type III secretion system inhibitors or inducers of the fire blight pathogen, Erwinia amylovora.

    Science.gov (United States)

    Khokhani, Devanshi; Zhang, Chengfang; Li, Yan; Wang, Qi; Zeng, Quan; Yamazaki, Akihiro; Hutchins, William; Zhou, Shan-Shan; Chen, Xin; Yang, Ching-Hong

    2013-09-01

    Erwinia amylovora causes a devastating disease called fire blight in rosaceous plants. The type III secretion system (T3SS) is one of the important virulence factors utilized by E. amylovora in order to successfully infect its hosts. By using a green fluorescent protein (GFP) reporter construct combined with a high-throughput flow cytometry assay, a library of phenolic compounds and their derivatives was studied for their ability to alter the expression of the T3SS. Based on the effectiveness of the compounds on the expression of the T3SS pilus, the T3SS inhibitors 4-methoxy-cinnamic acid (TMCA) and benzoic acid (BA) and one T3SS inducer, trans-2-(4-hydroxyphenyl)-ethenylsulfonate (EHPES), were chosen for further study. Both the T3SS inhibitors (TMCA and BA) and the T3SS inducer (EHPES) were found to alter the expression of T3SS through the HrpS-HrpL pathway. Additionally, TMCA altered T3SS expression through the rsmBEa-RsmAEa system. Finally, we found that TMCA and BA weakened the hypersensitive response (HR) in tobacco by suppressing the T3SS of E. amylovora. In our study, we identified phenolic compounds that specifically targeted the T3SS. The T3SS inhibitor may offer an alternative approach to antimicrobial therapy by targeting virulence factors of bacterial pathogens.

  10. Leaf development: A cellular perspective

    Directory of Open Access Journals (Sweden)

    Gerrit TS Beemster

    2014-07-01

    Full Text Available Through its photosynthetic capacity the leaf provides the basis for growth of the whole plant. In order to improve crops for higher productivity and resistance for future climate scenarios, it is important to obtain a mechanistic understanding of leaf growth and development and the effect of genetic and environmental factors on the process. Cells are both the basic building blocks of the leaf and the regulatory units that integrate genetic and environmental information into the developmental program. Therefore, to fundamentally understand leaf development, one needs to be able to reconstruct the developmental pathway of individual cells (and their progeny from the stem cell niche to their final position in the mature leaf. To build the basis for such understanding, we review current knowledge on the spatial and temporal regulation mechanisms operating on cells, contributing to the formation of a leaf. We focus on the molecular networks that control exit from stem cell fate, leaf initiation, polarity, cytoplasmic growth, cell division, endoreduplication, transition between division and expansion, expansion and differentiation and their regulation by intercellular signaling molecules, including plant hormones, sugars, peptides, proteins and microRNAs. We discuss to what extent the knowledge available in the literature is suitable to be applied in systems biology approaches to model the process of leaf growth, in order to better understand and predict leaf growth starting with the model species Arabidopsis thaliana.

  11. 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....

  12. 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....

  13. 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....

  14. 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

  15. 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....

  16. 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.

  17. Bacterial Hydrodynamics

    Science.gov (United States)

    Lauga, Eric

    2016-01-01

    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 micrometer 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, I review the biomechanics of bacterial motility and look ahead to future challenges.

  18. 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.

  19. First report of the crucifer pathogen Pseudomonas cannabina pv. alisalensis causing bacterial blight on radish (Raphanus sativus) in Germany

    Science.gov (United States)

    Pseudomonas cannabina pv. alisalensis is a severe pathogen of crucifers across the U.S. We compared a strain isolated from diseased radish (Raphanus sativus) in Germany to pathotypes and additional strains of P. cannabina pv. alisalensis and P. syringae pv. maculicola. We demonstrated that the patho...

  20. Transcriptome Alterations Resulting From Infection And Recovery Of Leafy Spurge To Cassava Bacterial Blight (Xanthomonas axonopodis pv. Manihotis)

    Science.gov (United States)

    Leafy spurge is a perennial rangeland weed that has been developed as a model weed system. An extensive EST database and cDNA microarrays containing more than 23,000 unigenes have been developed and used to characterize a variety of physiological processes from bud dormancy to drought stress and rec...

  1. The use of tissue culture techniques with irradiation to improve potato resistance to late blight

    International Nuclear Information System (INIS)

    A mutation breeding program was conducted to improve potato (Solanum tuberosum) resistance to late blight disease caused by Phytophthora infestans. In vitro cultured explants from potato cvs. Draga, Diamant, Spunta were irradiated with gamma ray doses 25, 30, and 35 Gy. Growing shoots were cut and re-cultured every 2 weeks until the 4th generation (MV4) to make sure no chimeral tissues still existed in the mutant material. Plantlets were subsequently propagated to obtain enough explants for in vitro selection pressure. Around 3000 plantlets from the three cultivars were subjected to selection pressure using co-culture technique. MV4 explants were incubated in jars, containing MS medium, with mycelia of P. infestans. Surviving plantlets were propagated and re-incubated with the pathogen for three consecutive generations. Resistant plantlets were acclimatized and transferred to pots and grown under glasshouse conditions. Plants were later inoculated, at the adult stage, with sporangial suspension. Cultivar Draga produced the highest number of resistant plants. Ten plants of Draga appeared to be resistant to late blight whereas only one plant from each of the other 2 cultivars was resistant. Mutant plants varied in number of produced minitubers from 13 to 70, Also, weight of these minitubers varied from less than 1 to 35 grams. Selected mutant lines will undergo further testing under field conditions for P. infestans resistance and other agronomic characteristics. (author)

  2. In vitro induction, isolation and selection of potato mutants resistant to late blight

    International Nuclear Information System (INIS)

    A mutation breeding program was conducted to improve potato resistance to late blight disease caused by Phytophthora infestans. In vitro cultured explants from cvs Draga, Diamant, Spunta were irradiated with gamma ray doses 25, 30, and 35 Gy. Growing shoots were cut and re-cultured every 2 weeks until the 4th generation (MV4) to make sure no chimeral tissues still existed in the mutant material. Plantlets were subsequently propagated to obtain enough explants for in vitro selection pressure. Around 3,000 plantlets from the 3 cultivars were subjected to selection pressure using co-culture technique. MV4 explants were incubated in jars, containing MS medium, with mycelia of P. infestans. Surviving plantlets were propagated and re-incubated with the pathogen for 3 consecutive generations. Resistant plantlets were acclimatized and transferred to pots and grown under glasshouse conditions. Plants were later inoculated, at the adult stage, with sporangial suspension. Cv Draga produced the highest number of resistant plants. Ten plants of Draga appeared to be resistant to late blight, whereas only one plant from each of the other 2 cvs was resistant. Mutant plants varied in number of produced minitubers from 13 to 70. Also, weight of these minitubers varied from less than 1 to 35 grams. Selected mutant lines will undergo further testing under field conditions for P. infestans resistance and other agronomic characteristics

  3. An Assessment of the Impact of Two Late Blight Tolerant Potato Varieties

    International Nuclear Information System (INIS)

    A study was made to assess the impact of two late blight tolerant potato varieties Tigoni and Asante releases in 1998. The appraisal and impact assessment set out to collect information on the adoption of the two varieties; assess their economic impact; and forecast future prospects for these two varieties and identity constraints to their adoption and diffusion in three divisions of Molo, Timboroa and Laikipia. The methodology adopted was conducting field surveys between September and October 2001, and gathering secondary information from the Ministry of Agriculture, research Centres, seed companies, NGO's and farmers. Results indicated that high yield, early maturity, tolerant to late blight, good market for ware potatoes and good taste were the advantages of Tigoni and Asante, widely recognised in all survey sites. Disadvantages of Tigoni and Asante were poor storage, rapid greening of tubers (mainly for Tigoni), and limited availability of planting material. The two varieties had higher yield benefits, net benefit per hectare and higher rates of return compared to the local varieties. the rate of returns when the local cultivars were substituted by the new improved varieties ranged from 556 to 1070%. Data on diffusion of Tigoni and Asante showed that combined acreage of varieties Tigoni and Asante rose to 196.3, 137.5 and 1476 ha in Molo, Timboroa and Laikipia respectively. The future forecast for the two varieties is good if the limitation on seed availability is addressed

  4. Strategies for managing Fusarium head blight and deoxynivalenol accumulation in wheat.

    Science.gov (United States)

    Yuen, Gary Y; Schoneweis, Susan D

    2007-10-20

    Many mycotoxigenic fungi infect plant hosts and cause disease in the field. Therefore, control of field infection by these fungi is a critical step in managing mycotoxin accumulation in the harvested product. Fusarium graminearum, also known as Gibberella zeae, is the causal agent of Fusarium head blight (FHB), or scab, in cereals and is also the primary agent responsible for contamination of grain with deoxynivalenol (DON). Research efforts worldwide are devoted to the development of strategies to control field infection of wheat and barley by this pathogen. Strategies include the use of fungicides and biological control agents to protect flowering heads from infection. There is extensive effort in breeding for host resistance to infection and spread of the pathogen within the heads. Scientists are also seeking exogenous traits to introduce into cereals to enhance resistance. Cultural practices are also being examined, primarily as measures to reduce pathogen survival and inoculum production in crop residues. The successes and limitations of these strategies in the management of Fusarium head blight and deoxynivalenol are discussed.

  5. Current progress on genetic interactions of rice with rice blast and sheath blight fungi

    Institute of Scientific and Technical Information of China (English)

    Yulin JIA; Guangjie LIU; Stefano COSTANZO; Seonghee LEE; Yuntao DAI

    2009-01-01

    Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens office resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.

  6. Effects of Fungicides, Time of Application, and Application Method on Control of Sclerotinia Blight in Peanut

    Directory of Open Access Journals (Sweden)

    Jason E. Woodward

    2015-01-01

    Full Text Available Field studies were conducted from 2007 to 2010 to evaluate the response of peanut cultivars to different fungicides, application timings, and methods. Overall, fungicides reduced Sclerotinia blight incidence and increased pod yields when applied to susceptible and partially resistant cultivars. Disease suppression was greater when full fungicide rates were applied preventatively; however, yields between fungicide treated plots were similar. Lower levels of disease and higher yields were achieved with the partially resistant cultivar Tamrun OL07 compared to the susceptible cultivars Flavor Runner 458 and Tamrun OL 02. Despite possessing improved resistance Tamrun OL07 responded to all fungicide applications. While similar levels of disease control were achieved with broadcast or banded applications made during the day or at night, the yield response for the different application methods was inconsistent among years. A negative relationship (slope = −73.8; R2=0.73; P<0.01 was observed between final disease incidence ratings and yield data from studies where a fungicide response was observed. These studies suggest that both boscalid and fluazinam are effective at controlling Sclerotinia blight in peanuts. Alternative management strategies such as nighttime and banded applications could allow for lower fungicide rates to be used; however, additional studies are warranted.

  7. Future prospects for ascochyta blight resistance breeding in cool season food legumes

    Directory of Open Access Journals (Sweden)

    Diego eRubiales

    2012-02-01

    Full Text Available Legume cultivation is strongly hampered by the occurrence of ascochyta blights. Strategies of control have been developed but only marginal successes have been achieved. Breeding for disease resistance is regarded the most cost efficient method of control. Significant genetic variation for disease resistance exists in most legume crops with numerous germplasm lines maintained, providing an excellent resource for plant breeders. Fast and reliable screening methods have been adjusted to fulfil breeding programmes needs. However, the complex inheritance controlled quantitatively by multiple genes, have been difficult to manipulate. Successful application of biotechnology to ascochyta blight resistance breeding in legume crops will facilitate both a good biological knowledge of the crops and of the mechanisms underlying resistance. The current focus in applied breeding is leveraging biotechnological tools to develop more and better markers to speed up the delivery of improved cultivars to the farmer. To date, however, progress in marker development and delivery of useful markers has been slow. The limited saturation of the genomic regions bearing putative QTLs in legume crops makes difficult to identify the most tightly-linked markers

  8. Mapping QTLs for Fusarium Head Blight Resistance in an Interspecific Wheat Population

    Science.gov (United States)

    Giancaspro, Angelica; Giove, Stefania L.; Zito, Daniela; Blanco, A.; Gadaleta, Agata

    2016-01-01

    Fusarium head blight (scab) is one of the most widespread and damaging diseases of wheat, causing grain yield and quality losses and production of harmful mycotoxins. Development of resistant varieties is hampered by lack of effective resistance sources in the tetraploid wheat primary gene pool. Here we dissected the genetic basis of resistance in a new durum wheat (Triticum turgidum ssp. durum) Recombinant inbred lines (RILs) population obtained by crossing an hexaploid resistant line and a durum susceptible cultivar. A total of 135 RILs were used for constituting a genetic linkage map and mapping loci for head blight incidence, severity, and disease-related plant morphological traits (plant height, spike compactness, and awn length). The new genetic map accounted for 4,366 single nucleotide polymorphism markers assembled in 52 linkage groups covering a total length of 4,227.37 cM. Major quantitative trait loci (QTL) for scab incidence and severity were mapped on chromosomes 2AS, 3AL, and 2AS, 2BS, 4BL, respectively. Plant height loci were identified on 3A, 3B, and 4B, while major QTL for ear compactness were found on 4A, 5A, 5B, 6A, and 7A. In this work, resistance to Fusarium was transferred from hexaploid to durum wheat, and correlations between the disease and morphological traits were assessed. PMID:27746787

  9. 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.

  10. Identification of Corn Bacterial Wilt Pathogen by Nested-PCR Based on 16S rDNA%16S nested-PCR技术检测玉米细菌性枯萎病菌

    Institute of Scientific and Technical Information of China (English)

    吴琼; 陈枝楠; 范怀忠; 金显忠

    2005-01-01

    玉米细菌性枯萎病是玉米上的重要种传病害,病原菌为Pantoea stewartii subsp.stewartii.本研究设计了16S通用引物,扩增该病菌及其近似种的16S rDNA,通过序列测定和分析,针对该病菌设计了特异性引物,采用nested-PCR技术,能够准确地区别该病菌及其近似种,检测的灵敏度在DNA水平上达到10-3pg级,检测活菌则达到2 cfu.检测人工污染的玉米种子时,不受种子提取液中其它物质的干扰,灵敏度依然达到2 cfu.%Pantoea stewartii subsp. stewartii is the seed-borne causative agent of bacterial wilt and leaf blight of sweet corn and maize. In this study, a specific 16S rDNA-based nested-PCR (nPCR) was developed to identify the bacterium from a range of closely related bacteria. This PCR assay was proved to be highly sensitive with the detection limit of 10 -3pg genomic DNA or 2 colony forming units (cfu). Moreover, this PCR assay successfully detected the target bacteria as few as 2 cfu when tested with artificially contaminated seeds, and the sensitivity was not affected by seed compounds.

  11. Tissue-specific expression of Arabidopsis NPR1 gene in rice for sheath blight resistance without compromising phenotypic cost.

    Science.gov (United States)

    Molla, Kutubuddin Ali; Karmakar, Subhasis; Chanda, Palas Kumar; Sarkar, Sailendra Nath; Datta, Swapan Kumar; Datta, Karabi

    2016-09-01

    Rice sheath blight disease, caused by the fungus Rhizoctonia solani, is considered the second most important disease of rice after blast. NPR1 (non expressor of PR1) is the central regulator of systemic acquired resistance (SAR) conferring broad spectrum resistance to various pathogens. Previous reports have indicated that constitutive expression of the Arabidopsis thaliana NPR1 (AtNPR1) gene results in disease resistance in rice but has a negative impact on growth and agronomic traits. Here, we report that green tissue-specific expression of AtNPR1 in rice confers resistance to the sheath blight pathogen, with no concomitant abnormalities in plant growth and yield parameters. Elevated levels of NPR1 activated the defence pathway in the transgenic plants by inducing expression of endogenous genes such as PR1b, RC24, and PR10A. Enhanced sheath blight resistance of the transgenic plants was evaluated using three different bioassay systems. A partially isolated toxin from R. solani was used in the bioassays to measure the resistance level. Studies of the phenotype and yield showed that the transgenic plants did not exhibit any kind of phenotypic imbalances. Our results demonstrate that green tissue-specific expression of AtNPR1 is an effective strategy for controlling the sheath blight pathogen. The present work in rice can be extended to other crop plants severely damaged by the pathogen. PMID:27457988

  12. Gene expression profiling during asexual development of the late blight pathogen Phytophthora infestans reveals a highly dynamic transcriptome

    NARCIS (Netherlands)

    Judelson, H.S.; Ah-Fong, A.M.V.; Aux, G.; Avrova, A.O.; Bruce, C.; Cakir, C.; Cunha, da L.; Grenville-Briggs, L.; Latijnhouwers, M.; Ligterink, W.; Meijer, H.J.G.; Roberts, S.; Thurber, C.S.; Whisson, S.C.; Birch, P.R.J.; Govers, F.; Kamoun, S.; West, van P.; Windass, J.

    2008-01-01

    Much of the pathogenic success of Phytophthora infestans, the potato and tomato late blight agent, relies on its ability to generate from mycelia large amounts of sporangia, which release zoospores that encyst and form infection structures. To better understand these stages, Affymetrix GeneChips bas

  13. Rainfall thresholds as support for timing fungicide applications in the control of potato late blight in Ecuador and Peru

    DEFF Research Database (Denmark)

    Kromann, Peter; Taipe, Arturo; Perez, Willmer G.;

    2009-01-01

    Accumulated rainfall thresholds were studied in seven field experiments conducted in Ecuador and Peru for their value in timing applications of fungicide to control potato late blight, caused by Phytophthora infestans. Fungicide regimes based on accumulated rainfall thresholds ranging from 10 to 70...

  14. Palisade Russet: A late blight resistant potato cultivar having a low incidence of sugar ends and high specific gravity

    Science.gov (United States)

    Palisade Russet is a medium-late maturing, lightly russeted potato breeding clone notable for its resistance to late blight (Phytophthora infestans) infection of foliage and tuber. Palisade Russet is suitable for processing with low tuber glucose concentrations observed following long-term storage ...

  15. Isolates of Rhizoctonia solani can produce both web blight and root rot symptoms in common bean (Phaseolus vulgaris L.)

    Science.gov (United States)

    Rhizoctonia solani Kühn (Rs) is an important pathogen in the tropics, causing web blight (WB), and a widespread soil-borne root rot (RR) pathogen of common bean (Phaseolus vulgaris L.) worldwide. This pathogen is a species complex classified into 14 anastomosis groups (AG). Some AGs have been report...

  16. FIRST REPORT OF BLOSSOM BLIGHT OF STRAWBERRY (FRAGARIA X ANANASSA DUCH.) CAUSED BY PSEUDOMONAS MARGINALIS IN CALIFORNIA.

    Science.gov (United States)

    A novel blossom blight was detected in commercial plantings of the strawberry (Fragaria x ananassa Duch.) in 2003 in central coastal California. Koch’s postulates were completed and etiology of the pathogen was determined. Physiological and molecular characterization showed that the pathogen was rel...

  17. Effective marker alleles associated with type II resistance of wheat to Fusarium head blight infection in fields

    Science.gov (United States)

    Molecular markers associated with known quantitative trait loci (QTLs) for type 2 resistance to Fusarium head blight (FHB) in bi-parental mapping populations usually have more than two alleles in breeding populations. Therefore, understanding the association of each allele with FHB response is parti...

  18. 马铃薯晚疫病的综合防治%Integrate control of potato late blight

    Institute of Scientific and Technical Information of China (English)

    宋伯符

    2001-01-01

    马铃薯晚疫病是马铃薯产区发生最普遍和最严重的真菌性病害,是具有毁灭性的病害,在大流行年份常造成马铃薯的绝产.因此世界各国专家都把马铃薯晚疫病作为马铃薯生产上的第一个最重要的病害.马铃薯晚疫病的防治以选育抗病品种为主,并结合药剂防治措施,以期达到控制马铃薯晚疫病发生的目的.%Potato late blight has been regarded as the most widely and serious fungal disease in potato production areas. It is one of the fatal diseases and often causes no production at all in the epidemic years. Hence specialists from all over the world regard potato late blight as the most serious disease in potato production. The main controlling method of potato late blight is to combine resistant varieties breeding with agricultural measures such as chemical spray etc. in an attempt to achieve the goal of controlling the occurrence and epidemic of potato late blight.

  19. Verification test on an innovated method for the studies on inheritance of resistance to rice sheath blight

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@We have recently developed a systematic method for the study on the inheritance of resistance to sheath blight. The key of the system is an innovated method of inoculation and investigation along with the employment of the permanent population. This paper reported the procedure of the system and the result of its verification.

  20. Molecular cytogenetic characterization of alien introgressions with gene Fhb3 for resistance to Fusarium head blight disease of wheat

    Science.gov (United States)

    Fusarium head blight (FHB) resistance was identified in the alien species Leymus racemosus, and wheat-Leymus introgression lines with FHB resistance were reported previously. Detailed molecular cytogenetic analysis of alien introgressions T01, T09, and T14 and the mapping of Fhb3, a new gene for FHB...

  1. Efficiacy of bumble bee disseminated biological control agents for control of Botrytis Blossom blight of Rabbiteye Blueberry

    Science.gov (United States)

    Botrytis blossom blight caused by Botrytis cinerea may cause severe crop loss in rabbiteye blueberry, necessitating applications of expensive fungicides. Commercial bumble bees, Bombus impatiens, were tested as vectors of the fungicidal biological control agents (BCAs), Prestop® Gliocladium catenula...

  2. Complete Genome Sequence of Pseudomonas fluorescens LBUM636, a Strain with Biocontrol Capabilities against Late Blight of Potato.

    Science.gov (United States)

    Morrison, Christopher K; Novinscak, Amy; Gadkar, Vijay J; Joly, David L; Filion, Martin

    2016-01-01

    Herein provided is the full-genome sequence of Pseudomonas fluorescens LBUM636. This strain is a plant growth-promoting rhizobacterium (PGPR) which produces phenazine-1-carboxylic acid, an antibiotic involved in the biocontrol of numerous plant pathogens, including late blight of potato caused by the plant pathogen Phytophthora infestans. PMID:27231373

  3. Competitive Interaction Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-spectrum Late Blight Resistance

    Science.gov (United States)

    The resistance (R) gene RB confers broad-spectrum resistance to potato late blight and belongs. The RB protein recognizes the presence of members of the Phytophthora infestans effector family IPI-O to elicit resistance. Most isolates of the pathogen contain IPI-O variants that are recognized by R...

  4. First report of Lasiodiplodia theobromae causing inflorescence blight and fruit rot of longan (Dimocarpus longan L.) in Puerto Rico

    Science.gov (United States)

    Longan is a tropical fruit tree in the Sapindaceae family. During a disease survey from 2008 to 2010, fruit rot and inflorescence blight (rotting of the rachis, rachilla and flowers) were observed at the USDA-ARS Research Farm in Isabela, Puerto Rico. Tissue sections (1 mm2) of diseased inflorescenc...

  5. Genome-wide association mapping of fusarium head blight resistance in wheat (Triticum aestivum L.) using genotyping by sequencing

    Science.gov (United States)

    Fusarium head blight (FHB) is one of the most important wheat diseases worldwide and host resistance displays complex genetic control. A genome-wide association study (GWAS) was performed on 273 winter wheat breeding lines from the mid-western and eastern regions of the US to identify chromosomal re...

  6. 通过构建单染色体片段代换系验证水稻细菌性条斑病抗性QTL qBlsr3d%Verification of QTL qBlsr3d Conferring Resistance to Bacterial Leaf Streak in Rice by Constructing SSSL

    Institute of Scientific and Technical Information of China (English)

    曹金良; 陈志伟; 林德塨; 吴为人; 谢小芳

    2014-01-01

    单染色体片段代换系是QTL精细定位的理想材料。水稻对细菌性条斑病的抗性属于典型的数量抗性。本研究以课题组构建的携有多个细条病抗性QTL (qBlsr3d, qBlsr5a和qBlsr5b)的近等基因系H359R为供体亲本,以感病品种H359为受体亲本,通过杂交,多次回交和自交,并结合分子标记辅助选择,成功构建了仅携有QTL qBlsr3d的单染色体片段代换系,命名为H359-BLSR3D。进一步通过分子标记定位分析表明:渗入区段位于第3号染色体分子标记3DSSR3和3DSSR12之间,物理距离约为1250 kb。田间接种鉴定表明:H359-BLSR3D与感病亲本H359间的细条病抗性差异显著,结果证明了抗性QTL qBlsr3d的真实存在。H359-BLSR3D将为QTL qBlsr3d的精细定位和最终克隆奠定基础。%Chromosome segment substitution line (CSSL) is an ideal material for fine mapping of QTL. Bacterial leaf steak (BLS) resistance in rice is quantitatively inherited. In the present study, using near-isogenic lines H359R with multi-resistant QTLs (qBlsr3d, qBlsr5a, qBlsr5b) as the donor parent (constructed by our group previous) and H359 as the recurrent parent, by cross, back-cross, self-cross and marker-based selection, single segment substitution line (SSSL) with qBlsr3d was developed. Further mapping showed that:the target fragment is located within a 1 250 kb region between markers 3DSSR3 and 3DSSR12 on chromosome 3. Inoculation experiment showed that the resistrance was statistically significant between H359-BLSR3D and H359, the result testify that QTL qBlsr3d is truly exsit. H359-BLSR3D would provide the basis for QTL qBlsr3d fine mapping and its final cloning.

  7. Hyperspectral remote sensing for advanced detection of early blight (Alternaria solani) disease in potato (Solanum tuberosum) plants

    Science.gov (United States)

    Atherton, Daniel

    Early detection of disease and insect infestation within crops and precise application of pesticides can help reduce potential production losses, reduce environmental risk, and reduce the cost of farming. The goal of this study was the advanced detection of early blight (Alternaria solani) in potato (Solanum tuberosum) plants using hyperspectral remote sensing data captured with a handheld spectroradiometer. Hyperspectral reflectance spectra were captured 10 times over five weeks from plants grown to the vegetative and tuber bulking growth stages. The spectra were analyzed using principal component analysis (PCA), spectral change (ratio) analysis, partial least squares (PLS), cluster analysis, and vegetative indices. PCA successfully distinguished more heavily diseased plants from healthy and minimally diseased plants using two principal components. Spectral change (ratio) analysis provided wavelengths (490-510, 640, 665-670, 690, 740-750, and 935 nm) most sensitive to early blight infection followed by ANOVA results indicating a highly significant difference (p < 0.0001) between disease rating group means. In the majority of the experiments, comparisons of diseased plants with healthy plants using Fisher's LSD revealed more heavily diseased plants were significantly different from healthy plants. PLS analysis demonstrated the feasibility of detecting early blight infected plants, finding four optimal factors for raw spectra with the predictor variation explained ranging from 93.4% to 94.6% and the response variation explained ranging from 42.7% to 64.7%. Cluster analysis successfully distinguished healthy plants from all diseased plants except for the most mildly diseased plants, showing clustering analysis was an effective method for detection of early blight. Analysis of the reflectance spectra using the simple ratio (SR) and the normalized difference vegetative index (NDVI) was effective at differentiating all diseased plants from healthy plants, except for the

  8. Study on Potato and Tomato Late Blights Controlled by 250 g/L Azoxystrobin SC in Wuling Mountain%250g/L嘧菌酯悬浮剂防治武陵山区马铃薯及番茄晚疫病的试验研究

    Institute of Scientific and Technical Information of China (English)

    向前; 刘传清; 张锋涛

    2011-01-01

    进行250 g/L嘧菌酯悬浮剂防治武陵山区马铃薯及番茄晚疫病的试验研究,结果表明:250 g/L嘧菌酯悬浮剂茎叶处理对马铃薯及番茄晚疫病均有一定的防效,速效性及持效性均显著或极显著优于对照药剂,并对作物安全,防病增产效果突出。%This paper disscussed potato and tomato late blights controlled by 250 g/L azoxystrobin SC in Wuling Mountain.The results showed that leaf dealing by 250 g/L azoxystrobin SC could control potato and tomato late blights in a certain extent,whose readily availability and continuity were significantly or remarkbly significantly superior than those of CK.250 g/L axoxystrobin SC was safe to crops,the effects of disease control and yield increasing were significant.

  9. 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.

  10. STATIC ANALYSIS OF LEAF SPRING

    OpenAIRE

    E VENUGOPAL GOUD; G HARINATH GOWD

    2012-01-01

    Leaf springs are special kind of springs used in automobile suspension systems. The advantage of leaf spring over helical spring is that the ends of the spring may be guided along a definite path as it deflects to act as a structural member in addition to energy absorbing device. The main function of leaf spring is not only tosupport vertical load but also to isolate road induced vibrations. It is subjected to millions of load cycles leading to fatigue failure. Static analysis determines the ...

  11. 一株水稻纹枯菌拮抗细菌的分离与鉴定%Isolation and identification of an antagonistic bacterium against Rhizoctonia solani, the causing agent of rice sheath blight

    Institute of Scientific and Technical Information of China (English)

    谢宗华; 高健; 王金宇; 彭喜旭; 唐新科; 王海华

    2012-01-01

    [目的]从土壤中分离并鉴定水稻纹枯菌拮抗细菌,测定其体外抑菌和温室防治效果.[方法]采用系列稀释法和平板对峙法筛选拮抗细菌,基于形态、生理特征及16S rDNA 序列鉴定其分类地位,采用种子细菌化温室试验测定其防效.[结果]从蔬菜根际土壤中筛选出一株纹枯菌拮抗细菌,命名为kwkjT4.菌株具有明显的体外抑菌活性,对水稻纹枯病的温室防效与井冈霉素相当,初步鉴定为假紫色色杆菌(Chromobacterium pseudoviolaceum).最适生长条件为pH 7.0,温度32℃,培养时间为36 h;抑菌活性物质产生的最适培养条件为pH 6.0,温度28℃,培养时间为48 h;表明两者并不一致.[结论]kwkjT4菌株在水稻纹枯病的生物防治中具有潜在的应用价值.这是C.pseudoviolaceum拮抗纹枯菌的首次报道.%[Objective] This study is aimed to isolate and characterize antagonistic bacteria from soil, and evaluate their in vitro inhibition and control efficacy against Rhizoctonia solani, the causing agent of rice sheath blight in a green house. [Methods] Serial dilution method and dual culture technique on agar plate were used for screening bacteria. Strain identification was based on morphological and physiological characteristics, and phylogenetic analysis of 16S rDNA sequence. Control efficacy against rice sheath blight was evaluated by seed bacteriza-tion tests in a green house. [Results] An antagonistic bacterial strain against Rhizoctonia solani was isolated and screened from vegetable rhizosphere soil. The strain, designated as kwkjT4, exhibited excellent in vitro inhibition against the fungal pathogen. Its control efficacy against rice sheath blight was comparable to that of jinggangmycin. It was preliminarily identified as a strain of Chromobacterium pseudoviolaceum. The optimal growth conditions of the strain were as follows: pH 7.0, temperature 32 ℃, incubation time 36 h. Inconsistence with those for the bacterial growth, the

  12. Genome Sequence of a Xylella fastidiosa Strain Causing Mulberry Leaf Scorch Disease in Maryland.

    Science.gov (United States)

    Guan, Wei; Shao, Jonathan; Zhao, Tingchang; Huang, Qi

    2014-01-01

    Xylella fastidiosa causes bacterial leaf scorch in landscape trees, including mulberry. We determined the draft genome of the mulberry strain Mul-MD in order to gain a better understanding of the molecular basis of strain divergence, host specificity, nutrient requirements, and pathogenicity, as well as to develop genome-based specific detection methods. PMID:24604658

  13. 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 ...

  14. Preliminary identification of bacterial strain causing Anthurium bacterial blight%红掌细菌性疫病的病原菌初步鉴定

    Institute of Scientific and Technical Information of China (English)

    姬广海; 魏亚东; 蒋桂芝; 管旭芳; 喻盛甫; 刘昌芬

    2004-01-01

    在云南西双版纳的红掌上发现一种由细菌侵染引起的病害,从叶片的病组织上分离到具有致病性的杆状细菌,将分离的病原菌接种于健康的红掌上,表现出与田间一致的症状.感病初期在叶缘或叶脉间出现水渍状小点,后期病斑多呈棕褐色至黑色坏死,病健交界处多呈黄色.从接种发病的病斑与田间标样上分离的病原菌菌落形态完全相同.通过菌株的培养性状、常规生理生化特性及透射电镜下菌体形态观察结果,将病原菌初步鉴定为黄单胞菌属(Xanthomonas).BIOLOG鉴定和致病性测定结果进一步鉴定病原菌为地毯草黄单胞菌花叶万年青致病变种Xanthomonas axonopodis pv.dieffenbachiae(Xad)(McCulloch & Pirone)Vauterin et al..

  15. Proteomics Identification of Differentially Expressed Leaf Proteins in Response to Setosphaeria turcica Infection in Resistant Maize

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-li; SI Bing-wen; FAN Cheng-ming; LI Hong-jie; WANG Xiao-ming

    2014-01-01

    Northern corn leaf blight (NCLB), caused by the heterothallic ascomycete fungus Setosphaeria turcica, is a destructive foliar disease of maize and represents a serious threat to maize production worldwide. A comparative proteomic study was conducted to explore the molecular mechanisms underlying the defense responses of the maize resistant line A619 Ht2 to S. turcica race 13. Leaf proteins were extracted from mock and S. turcica-infected leaves after inoculated for 72 h and analyzed for differentially expressed proteins using two-dimensional electrophoresis and mass spectrometry identiifcation. 137 proteins showed reproducible differences in abundance by more than 2-fold at least, including 50 up-regulated proteins and 87 down-regulated proteins. 48 protein spots were successfully identiifed by MS analysis, which included 10 unique, 6 up-regulated, 20 down-regulated and 12 disappeared protein spots. These identiifed proteins were classiifed into 9 functional groups and involved in multiple functions, particularly in energy metabolism (46%), protein destination and storage (12%), and disease defense (18%). Some defense-related proteins were upregulated such asβ-glucosidase, SOD, polyamines oxidase, HSC 70 and PPIases; while the expressions of photosynthesis- and metabolism-related proteins were down-regulated, by inoculation with S. turcica. The results indicated that a complex regulatory network was functioned in interaction between the resistant line A619 Ht2 and S. turcica. The resistance processes of A619 Ht2 mainly resided on directly releasing defense proteins, modulation of primary metabolism, affecting photosyntesis and carbohydrate metabolism.

  16. 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.

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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

  2. What determines a leaf's shape?

    Science.gov (United States)

    Dkhar, Jeremy; Pareek, Ashwani

    2014-01-01

    The independent origin and evolution of leaves as small, simple microphylls or larger, more complex megaphylls in plants has shaped and influenced the natural composition of the environment. Significant contributions have come from megaphyllous leaves, characterized usually as flat, thin lamina entrenched with photosynthetic organelles and stomata, which serve as the basis of primary productivity. During the course of evolution, the megaphylls have attained complexity not only in size or venation patterns but also in shape. This has fascinated scientists worldwide, and research has progressed tremendously in understanding the concept of leaf shape determination. Here, we review these studies and discuss the various factors that contributed towards shaping the leaf; initiated as a small bulge on the periphery of the shoot apical meristem (SAM) followed by asymmetric outgrowth, expansion and maturation until final shape is achieved. We found that the underlying factors governing these processes are inherently genetic: PIN1 and KNOX1 are indicators of leaf initiation, HD-ZIPIII, KANADI, and YABBY specify leaf outgrowth while ANGUSTIFOLIA3 and GROWTH-REGULATING FACTOR5 control leaf expansion and maturation; besides, recent research has identified new players such as APUM23, known to specify leaf polarity. In addition to genetic control, environmental factors also play an important role during the final adjustment of leaf shape. This immense amount of information available will serve as the basis for studying and understanding innovative leaf morphologies viz. the pitchers of the carnivorous plant Nepenthes which have evolved to provide additional support to the plant survival in its nutrient-deficient habitat. In hindsight, formation of the pitcher tube in Nepenthes might involve the recruitment of similar genetic mechanisms that occur during sympetaly in Petunia. PMID:25584185

  3. Variations in Disease Resistance of Chestnut Cultivars against Chestnut Blight Fungus, Cryphonectria parasitica

    Institute of Scientific and Technical Information of China (English)

    LEE Sanghyun; KIM Kyunghee; PIAO Chungen; MOON Byungju

    2006-01-01

    Chestnut blight caused by Cryphonectria parasitica is one of the major chestnut diseases occurred on stems and branches. Oriental chestnut has more resistance than American one. Twenty-five cultivars of chestnut tree including various cultivars such as Tsukuba, Okkwang, Rihei, Ginyose, Eunsan, etc. Were tested with a rapid, simple and reliable method. The cultivar Banseki is one of the most resistant cultivars tested and has the necrotic area of 0.40 cm2. However, the necrotic areas of the cultivars of American chestnut, Eunsan, Kwangjujoyul and Eaton, ranges from 3.35 to 2.61 cm2 and these cultivars are relatively susceptible to this pathogen. Many pycnidia of this pathogen were observed on the inner and outer bark tissues after incubating for 3 weeks.

  4. Antifungal activity of Syzygium cumini against Ascochyta rabiei-the cause of chickpea blight.

    Science.gov (United States)

    Jabeen, Khajista; Javaid, Arshad

    2010-07-01

    Aqueous, ethanol and n-hexane extracts from leaves, fruit, root-bark and stem-bark of Syzygium cumini (L.) Skeels were tested for their antifungal activity against Ascochyta rabiei (Pass.) Lab., the cause of blight disease of the chickpea (Cicer arietinum L.). Different concentrations, namely 1, 2, ..., 5% of both aqueous and the two organic solvent extracts were used in this study. Aqueous extracts of all the four test plant parts, namely leaves, fruit, stem-bark and root-bark, showed significant antifungal activity resulting in 7-30%, 22-59%, 23-39% and 21-64% reduction in fungal growth, respectively. Similarly, n-hexane stem-bark extract, and ethanol root- and stem-bark extracts also significantly suppressed the growth of target fungal species, resulting in 17-39%, 24-30% and 12-32% suppression in fungal growth. PMID:19588279

  5. Interactions between chestnut gall wasp and blight: a new criticality for chestnut

    Directory of Open Access Journals (Sweden)

    Turchetti T

    2010-12-01

    Full Text Available The fast spread of Chinese gall wasp (Dryocosmus kuriphilus represents a new constraint factor for chestnut stands and orchards in Italy. So far, the favourable effect of hypovirulence in Cryphonectria parasitica-Castanea sativa patho-system allowed the development of chestnut cultivation. This situation could be modified by the progressive weakening of the trees caused by intensive attacks of the new parasite. During recent surveys worrying blight damage recurrences were observed in different Italian chestnut areas (in Piemonte, Trentino and Toscana regions which were highly infested by the Chinese wasp. While biological control treatments against the parasite are carried out, it is necessary to set up integrated protocols for the management of chestnut orchards to allow the survival of trees and their productivity.

  6. Non-conventional possibilities of protection of apple and pear against fire blight (Erwinia amylovora

    Directory of Open Access Journals (Sweden)

    Piotr Sobiczewski

    2013-12-01

    Full Text Available Standard program of plant protection against fire blight consists of use of management practices and chemical control method. Recently a new, non-conventional possibilities based on application of biocontrol agents (two biopreparations have been already introduced into practice: Bliteban A506 (Pseudomonas fluorescens and BlossomBless (Pantoea agglomerans, plant extracts active against Erwinia amylovora (AkseBio containing extracts from Thymbra spicata and Biomit Plussz with extracts from various plant species and microelements and resistance inducers (Regalis, Bion and plant extracts are of great interest. Also plant transformation with resistance genes such as: hrpN (harpin, dpo (EPS depolymerase and lytic protein genes (attacin E, cecropin SB-37, T4 lysozyme is a promising perspective.

  7. Reduction of lesion growth rate of late blight plant disease in transgenic potato expressing harpin protein

    Institute of Scientific and Technical Information of China (English)

    李汝刚; 范云六

    1999-01-01

    Using harpin protein gene from apple fire blight pathogen Erwinia amylavora and potato prp1-1 promoter as main DNA elements, the feasibility of using pathogen infection-induced hypersensitive response was explored as a new strategy of engineering fungal disease resistance. Three plant transformation vectors were constructed and 68 transgenic potato plants were produced through Agrobacterium mediated transformation method. Southern, Northern and Western blot analysis demonstrated the insertion, transcription and protein expression of harpin protein gene in transgenic plants. Disease resistance test using a complex race of Phytophthora infestans as challenging pathogen showed that both constitutive and pathogen infection-induced expression of harpin protein gene in transgenic potato reduced the lesion growth rate of fungus. Among plants where harpin protein gene expression was induced only by fungus infection, two plants were found to be highly resistant to P. infestans infection. Fungal hyphae were not pr

  8. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

    Science.gov (United States)

    Simonin, Kevin A; Burns, Emily; Choat, Brendan; Barbour, Margaret M; Dawson, Todd E; Franks, Peter J

    2015-03-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO₂ concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO₂ concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO₂ on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO₂ assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  9. ROLE OF EPIDEMIOLOGICAL AND BIOCHEMICAL FACTORS AGAINST EARLY BLIGHT OF POTATO

    Directory of Open Access Journals (Sweden)

    Muhammad Idrees

    2013-04-01

    Full Text Available Epidemiological and biochemical factors play a significant role in early blight disease development in potatoes. For this 29 test cultivars/ lines, were screened, 15 lines including Cardinal and Desiree were found to be very highly susceptible. Eight lines including Diament FSD-White, and TPS-9813 showed highly susceptible response. Two lines i.e. 9802 and 396266-33 were susceptible. Only one variety /advanced line FD-1-8 was found to be resistant. None of the 29 advanced lines was found to be highly resistant while two lines such as FD-3-9 and FD-48-41 were shown moderately resistant response. At varietal level, among 29 test varieties/ advanced lines, all the varieties showed highly significant correlation with minimum temperature and negative correlation with maximum temperature. 18 varieties/advanced lines have significant correlation with pan evaporation. Whereas all the 29 varieties/ advanced lines did not show any correlation with relative humidity and wind speed. Five varieties/ advanced lines namely Cardinal, 396240-181, 9803, FD-1-9 and 9801 were selected to study the relationship of environmental conditions with disease severity. Maximum disease severity was recorded at 17-200C maximum temperature, 6-9oC of minimum air temperature and 1.9-2.4 mm pan evaporation. Relative humidity and wind speed almost had no significant effect on disease severity. On varietal level early blight disease severity had significant correlation with phenolic production both in leaves and tubers. Among 29 varieties, 20 varieties had significant correlation with phenolic production while 9 had no correlation in case of leaves while in case of tubers 19 varieties/ lines showed significant correlation & 10 lines did not show any correlation with phenolics production. 

  10. Evaluation of Susceptibility of Different Pear Hybrid Populations to Fire Blight (Erwinia amylovora

    Directory of Open Access Journals (Sweden)

    Yasemin EVRENOSOĞLU

    2011-05-01

    Full Text Available Fire blight disease caused by pathogenic bacterium Erwinia amylovora, is the serious disease of pear, and there is not a certain chemical management against this disease except antibiotic-type compounds such as streptomycin. It is very important to improve new fire blight resistant cultivars in case of integrated disease management. With this purpose, different crosses have been made between Pyrus communis varieties that have good fruit characteristics and resistant cultigens. Besides, self and open pollination treatments have been carried out in maternal plants. The disease resistance level of the hybrids obtained from these combinations was determined by artificial inoculations by Erwinia amylovora in greenhouse conditions. A total of 3284 hybrids were inoculated, and 2631 of them survived and were distributed to different susceptibility classes. 19.88% of the inoculated hybrids was killed by Erwinia amylovora. Total distribution of the hybrids to susceptibility classes was as 6.18% in class “A- slightly susceptible”, 3.11% in class “B- less susceptible”, 8.89% in class “C- mid-susceptible”, 20.28% in class “D- susceptible”, and 61.54% in class “E- very susceptible”. Majority of class “A- slightly susceptible” hybrids were obtained from ‘Magness’ x ‘Ankara’ combination. ‘Kieffer’ x ‘Santa Maria’, ‘Kieffer’ open pollination, ‘Magness’ x ‘Akça’, ‘Magness’ x ‘Kieffer’, ‘Magness’ x ‘Santa Maria’, ‘Mustafa Bey’ x ‘Moonglow’ treatments displayed good results with respect to “A- slightly susceptible” character. It is very important to evaluate these hybrid pear populations through different fruit and tree characteristics in the future.

  11. Efficacy of Bacillus subtilis MBI 600 Against Sheath Blight Caused by Rhizoctonia solani and on Growth and Yield of Rice

    Institute of Scientific and Technical Information of China (English)

    K. VIJAY KRISHNA KUMAR; M. E. MILLER; S. KR. YELLAREDDYGARI; M. S. REDDY; J. W. KLOEPPER; K. S. LAWRENCE; X. G. ZHOU; H. SUDINI; D. E. GROTH; S. KRISHNAM RAJU

    2012-01-01

    Rice sheath blight disease (ShB),caused by Rhizoctonia solani,gives rise to significant grain yield losses.The present study evaluated the efficacy of Integral(R),the commercial liquid formulation of Bacillus subtilis strain MBI 600,against rice ShB and for plant growth promotion.In greenhouse studies,four log concentrations of Integral (from 2.2×106to 2.2×109 cfu/mL) were used as seed treatment (ST) After 25 d,seedlings were dipped (SD) into integral prior to transplanting.At 30 d after transplanting (DAT),leaf sheaths were inoculated with immature sclerotia of the pathogen.At 45 DAT,a foliar spray (FS) with Integral was applied to some treatments.The fungicide control was 50% carbendazim at 1.0 g/L,and a nontreated control was also included.Overall,there were 10 treatments,each with five replications.ShB severity was rated at 52 DAT,and seedling height and number of tillers per plant were rated at 60 DAT.In 2009,two field trials evaluated Integral at 2.2×108 and 2.2×109 cfu/mL.Integral was applied as ST,and seedlings were produced in a nursery bed.After 32 d,seedlings were treated with integral as SD and transplanted into 10 m2 blocks.Foliar sprays were given at 45 and 60 DAT.There were seven treatments,each with eight replications arranged as a factorial randomized complete block design.At 20 DAT,the plots were broadcast inoculated with R.solani produced on rice grains.Seedling height before transplanting,ShB severity at 90 DAT,and grain yield at harvest were recorded.Integral at 2.2×109 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions.The Integral treatments of ST + SD + FS at 2.2×108 cfu/mL significantly suppressed ShB over other treatments.In field studies,Integral provided significant increase of seedling height in nursery,and number of tillers per plant,compared with the control.ShB severity was significantly suppressed with higher concentrations of Integral compared to lower

  12. 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. PMID:24392817

  13. Antibiofilm activity of Dendrophthoe falcata against different bacterial pathogens.

    Science.gov (United States)

    Karthikeyan, Alagarsamy; Rameshkumar, Ramakrishnan; Sivakumar, Nallusamy; Al Amri, Issa S; Karutha Pandian, Shunmugiah; Ramesh, Manikandan

    2012-12-01

    Dendrophthoe falcata is a hemiparasitic plant commonly used for ailments such as ulcers, asthma, impotence, paralysis, skin diseases, menstrual troubles, pulmonary tuberculosis, and wounds. In this context, the validations of the traditional claim that the leaf extract of D. falcata possesses antibiofilm and anti-quorum sensing activity against different bacterial pathogens were assessed. The bacterial biofilms were quantified by crystal violet staining. Among the 17 bacterial pathogens screened, the methanolic fraction of the leaf extract clearly demonstrated antibiofilm activity for Proteus mirabilis, Vibrio vulnificus, Aeromonas hydrophila, Shigella sonnei, Chromobacterium violaceum ATCC 12472, Vibrio parahaemolyticus, Vibrio harveyi, Vibrio alginolyticus, Vibrio cholerae, and Proteus vulgaris. At biofilm inhibitory concentrations, biofilm formation was reduced by up to 70-90 %. Furthermore, the potential quorum-sensing activity of the leaf extract was tested by agar well diffusion using Chromobacterium violaceum (ATCC 12472 & CV O26) reporter strains. The inhibition of violacein production may be due to direct or indirect interference on QS by active constituents or the interactive effect of different phytocompounds present in the extracts. This is the first report on antibiofilm and QS activity of D. falcata leaf extracts, signifying the scope for development of complementary medicine for biofilm-associated infections. PMID:23115018

  14. Antipyretic and antibacterial activity of Chloranthus erectus (Buch.-Ham.) Verdcourt leaf extract: A popular folk medicine of Arunachal Pradesh

    OpenAIRE

    Tag, Hui; Nima D Namsa; Mandal, M; Kalita, P; Das, AK; Mandal, SC

    2010-01-01

    Objective: The main objective of this work was to study the antipyretic and antibacterial activity of C. erectus (Buch.-Ham.) Verdcourt leaf extract in an experimental albino rat model. Materials and Methods: The methanol extract of C. erectus leaf (MECEL) was evaluated for its antipyretic potential on normal body temperature and Brewer’s yeast-induced pyrexia in albino rat’s model. While the antibacterial activity of MECEL against five Gram (−) and three Gram (+) bacterial strains and antimy...

  15. The Eschericia coli Growth Inhibition Activity of Some Fermented Medicinal Plant Leaf Extract from the Karo Highland, North Sumatra

    OpenAIRE

    NOVIK NURHIDAYAT; EVI TRIANA

    2009-01-01

    A lot of traditional medicinal plant has antibacterial acitivities. Most of these plants are freshly chewed or grounded and used directly to treat infectious bacterial deseases. However, some practices employ a traditionally spontaneous fermentation on boiled extracted leaf, root or other parts of the plant. This work reports a laboratory stimulated spontaneous fermentation of leaf extracts from selected medicinal plants collected from the Karo Higland. The spontaenous fermentation was stimul...

  16. Severidade da mela da soja causada por Rhizoctonia solani AG-1 IA em função de doses de potássio Severity of hte foliar blight of the soylean caused by Rhizoctonia solani AG-1 IA infunction of doses of potassium

    Directory of Open Access Journals (Sweden)

    Marco Antonio Basseto

    2007-03-01

    Full Text Available O fungo Rhizoctonia solani pertencente ao grupo de anastomose 1 IA (AG-1 IA é um dos patógenos mais importantes afetando a cultura da soja no Brasil. Este fungo causa queima da folha e/ou mela em soja, para a qual medidas de manejo cultural são consideradas alternativas importantes para controle antes do estabelecimento da doença. Há evidências de que a adubação potássica diminui substancialmente a severidade dos sintomas de várias doenças da soja como a queima foliar (Cercospora kikuchii, a seca da haste e da vagem (Phomopsis phaseoli var. sojae e o cancro da haste (Diaporthe phaseolorum f. sp. meridionalis. Apesar das evidências do efeito do potássio no controle de várias doenças da soja, não há informação na literatura sobre o efeito desse nutriente no controle da mela. A hipótese testada foi que a mela da soja pode ser controlada através de incrementos na adubação potássica. De maneira geral, concluiu-se que, sob condições de casa de vegetação, o incremento de K no solo não resultou no controle da mela da soja. É necessário, entretanto, confirmar esta observação conduzindo-se experimentos sob condições de campo, podendo-se incluir a avaliação do efeito da doença sob aspectos da produção.The fungus Rhizoctonia solani, belonging to anastomosis group 1IA (AG-1 IA is one of the most important pathogens affecting soybean in Brazil. This fungus causes aerial or foliar blight of soybean, and cultural measures are thought as important choices for the control before the establishment of the disease. Based on evidences that potassium amendments can substantially reduce the severity of several soybean diseases such as Cercospora leaf blight (Cercospora kikuchii, pod and stem blight (Phomopsis phaseoli var. sojae and stem canker (Diaporthe phaseolorum f. sp. meridionalis. Despite all evidence, there is no information in the literature about the effect of potassium controlling the soybean foliar blight. The

  17. 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.

  18. Conventional and real-time PCRs for detection of Erwinia piriflorinigrans allow its distinction from the fire blight pathogen, Erwinia amylovora.

    Science.gov (United States)

    Barbé, Silvia; Bertolini, Edson; Roselló, Montserrat; Llop, Pablo; López, María M

    2014-04-01

    Erwinia piriflorinigrans is a new pathogenic species of the bacterial genus Erwinia that has been described recently in Spain. Accurate detection and identification of E. piriflorinigrans are challenging because its symptoms on pear blossoms are similar to those caused by Erwinia amylovora, the causal agent of fire blight. Moreover, these two species share phenotypic and molecular characteristics. Two specific and sensitive conventional and real-time PCR protocols were developed to identify and detect E. piriflorinigrans and to differentiate it from E. amylovora and other species of this genus. These protocols were based on sequences from plasmid pEPIR37, which is present in all strains of E. piriflorinigrans analyzed. After the stability of the plasmid was demonstrated, the specificities of the protocols were confirmed by the amplification of all E. piriflorinigrans strains tested, whereas 304 closely related pathogenic and nonpathogenic Erwinia strains and microbiota from pear trees were not amplified. In sensitivity assays, 10(3) cells/ml extract were detected in spiked plant material by conventional or real-time PCR, and 10(2) cells/ml were detected in DNA extracted from spiked plant material by real-time PCR. The protocols developed here succeeded in detecting E. piriflorinigrans in 102 out of 564 symptomatic and asymptomatic naturally infected pear samples (flowers, cortex stem tissue, leaves, shoots, and fruitlets), in necrotic Pyracantha sp. blossoms, and in necrotic pear and apple tissues infected with both E. amylovora and E. piriflorinigrans. Therefore, these new tools can be used in epidemiological studies that will enhance our understanding of the life cycle of E. piriflorinigrans in different hosts and plant tissues and its interaction with E. amylovora.

  19. Control technique of sphaeropsis shoot blight in Pinus teada%火炬松枯梢病防治技术

    Institute of Scientific and Technical Information of China (English)

    沈友爱

    2001-01-01

    Sphaeropsis shoot blight in Pinus teada is a serious disease in south of China.The control experiments of cutting blight shoots,applying fertilizer and spraying fungicide were made ,The result shows that the above measures combined with spraying 50% Carbendazim wp could reach an efficacy of 88.6%.%火炬松枯梢病Sphaeropsis sapinea是为害火炬松Pinus taeda的毁灭性病害。该文通过剪枯梢、施肥和喷药相结合进行防治试验,结果表明:以剪枯梢为主,结合施肥或喷50%多菌灵的防治措施效果较好,防治率88.6%。

  20. Hyperspectral remote sensing for advanced detection of early blight (Alternaria solani) disease in potato (Solanum tuberosum) plants

    Science.gov (United States)

    Atherton, Daniel

    Early detection of disease and insect infestation within crops and precise application of pesticides can help reduce potential production losses, reduce environmental risk, and reduce the cost of farming. The goal of this study was the advanced detection of early blight (Alternaria solani) in potato (Solanum tuberosum) plants using hyperspectral remote sensing data captured with a handheld spectroradiometer. Hyperspectral reflectance spectra were captured 10 times over five weeks from plants grown to the vegetative and tuber bulking growth stages. The spectra were analyzed using principal component analysis (PCA), spectral change (ratio) analysis, partial least squares (PLS), cluster analysis, and vegetative indices. PCA successfully distinguished more heavily diseased plants from healthy and minimally diseased plants using two principal components. Spectral change (ratio) analysis provided wavelengths (490-510, 640, 665-670, 690, 740-750, and 935 nm) most sensitive to early blight infection followed by ANOVA results indicating a highly significant difference (p potato plants.

  1. 植物内生细菌在辣椒体内的定殖动态及对辣椒疫病的防治效果%Colonization Dynamics of Endophytic Bacteria in Capsicum annuum and Their Control Effects on Pepper Phytophthora Blight

    Institute of Scientific and Technical Information of China (English)

    付思娅; 陈双林; 闫淑珍

    2013-01-01

    为了探讨具生防作用的植物内生细菌在辣椒体内的定殖动态与其防治辣椒疫病的关系,采用对峙培养法和盆栽苗防效法筛选生防菌株,依据菌体形态、生理生化性质和16S rDNA序列鉴定菌种,用抗利福平标记研究菌株在辣椒苗中的定殖动态,在同时接入植物内生细菌和灌根接种辣椒疫霉菌的条件下分析生防菌株的定殖数量与防效的关系。结果表明,菌株G9、R15和J13对辣椒疫病防效最好,经鉴定均为荧光假单胞菌Pseudomonas fluorescens。菌株G9和R15在辣椒根部定殖量高于菌株J13;定殖周期均在30~40 d,呈“先增后减”的变化趋势;菌株G9和R15在接种第15 d时定殖量最高,菌株J13在根、茎和叶中定殖量达到最高的天数分别为第9、15和15~20 d,定殖数量的变化为根>茎>叶。菌株G9定殖量达到9.73×105 cfu·g−1时辣椒疫病的防效达到100%,保持该数量的时间约6 d;菌株R15定殖量达到6.30×105 cfu·g−1以上时对辣椒疫病的防效达到100%,保持该数量的时间约14 d。研究结果展现了植物内生细菌在辣椒疫病生物防治上的应用潜力,为制定植物内生细菌防治辣椒疫病的施用技术提供了科学依据。%In order to clarify the relationships between colonization dynamics of endophytic bacteria and the control effects on pepper Phytophthora blight, endophytic bacterial strains were screened by dual culturing against Phytophthora capsici and control effects were measured on the potted seedlings. The endophytic bacteria were identified based on their morphological characteristics, biochemical characteristics and 16S rDNA sequence BLAST. Colonization dynamics of endophytic bacteria in seedlings of Capsicum annuum were also conducted by rifampicin labelling and their relationships with control effects were analyzed. The results showed that three endophytic bacterial strains G9, R15 and J13 had obvious

  2. How to pattern a leaf.

    Science.gov (United States)

    Bolduc, N; O'Connor, D; Moon, J; Lewis, M; Hake, S

    2012-01-01

    Leaf development presents a tremendous resource for tackling the question of patterning in biology. Leaves can be simple or highly dissected. They may have elaborated parts such as the tendrils of a pea leaf or the rolled blade of a carnivorous pitcher plant. Despite the variation in size, shape, and function, all leaves initiate in the same manner: from the flanks of a meristem. The maize leaf is useful for analysis of patterning due to the wealth of mutants and the distinct tissues along the proximal distal axis. The blade is distal, the sheath is proximal, and the ligule forms at the blade/sheath boundary. Establishment of this boundary involves the transcription factors LIGULELESS1 and LIGULELESS2 and the kinase LIGULELESS NARROW. The meristem-specific protein KNOTTED1 (KN1) binds and modulates the lg2 gene. Given the localization of KN1 at the proximal end of the leaf from the time of inception, we hypothesize that KN1 has a role in establishing the very proximal end of the leaf, whereas an auxin maximum guides the growing distal tip. PMID:23174765

  3. Transcriptome analysis of root response to citrus blight based on the newly assembled Swingle citrumelo draft genome

    OpenAIRE

    Zhang, Yunzeng; Barthe, Gary; Grosser, Jude W.; Wang, Nian

    2016-01-01

    Background Citrus blight is a citrus tree overall decline disease and causes serious losses in the citrus industry worldwide. Although it was described more than one hundred years ago, its causal agent remains unknown and its pathophysiology is not well determined, which hampers our understanding of the disease and design of suitable disease management. Results In this study, we sequenced and assembled the draft genome for Swingle citrumelo, one important citrus rootstock. The draft genome is...

  4. EVALUATION OF DISEASE RESISTANCE POTENTIAL OF SEVEN POTATO GENOTYPES AGAINST EARLY BLIGHT CAUSED BY Alternaria tenuissima UNDER GREENHOUSE CONDITIONS

    OpenAIRE

    Hamid Reza Mirkarimi; Ahmad Abasi Moghadam; Javad Mozafari

    2013-01-01

    Early blight of potato was caused by various species of genus Alternaria, the disease has a prominent role in reducing crop yields in most of the countries, especially in Iran. Various studies has been conducted for the finding out the information regarding the diversity of pathogen and estimation of damage caused by genus Alternaria tenuissima in Iran, but the information regarding the resistance against this fungal pathogen in various genotype of potatoes are in scarcity. Seven isolat...

  5. Incidence and etiology of maize seedling blight and control of soil borne pathogens using seed treatments / Johnny Viviers

    OpenAIRE

    Viviers, Johnny

    2014-01-01

    Seedling blight of maize has significantly influenced field crop stands and seedling vigour over various localities and seasons. The extent of the problem is influenced by a number of factors which includes soil temperature (generally below 13 °C), waterlogged soils, inadequate fertilization, herbicide damage and fungal pathogens. The fungi generally causing seedling damping off are often involved in a complex and succession over time varying in importance depending on the field circumstances...

  6. Progresso do crestamento gomoso e perdas na cultura da melancia Disease progress and crop losses due to watermelon gummy stem blight

    Directory of Open Access Journals (Sweden)

    Gil R. dos Santos

    2005-06-01

    32 m were established in areas free of the disease, without any history of cucurbit cultivation, and no control measures were applied. Data for the disease progress curves were obtained from the mean diseased leaf area in an area of 768 m², at 45; 50; 55; 60; 65; 74; 80 and 87 days after planting (DAP. Disease progressed according to the exponential model, even under marginally favorable environmental conditions. Maximum severity values were observed 87 DAP (12.5-13.6% diseased leaf area. The crop loss experiment was laid out in a randomized completed block design with five disease levels and four replicates. Disease levels were obtained with the application of five fungicide doses (per 100 L of water of a mixture of active ingredients chlorothalonil and methyl thiophanate, as follows: (a 0 g a.i. (control; (b chlorothalonil 25 g + methyl thiophanate 10 g; (c chlorothalonil 75 g + methyl thiophanate 30 g; (d chlorothalonil 125 g + methyl thiophanate 50 g; (e chlorothalonil 250 g + methyl thiophanate 100 g. Disease severity was evaluated once, 78 DAP, with a disease scale ranging from 0 to 9, based on the percentage of diseased leaf area. Maximum disease levels were observed 78 DAP in control plots (26.5% diseased leaf area. There was high negative correlation (r=-0.96 between disease levels and fruit yield. Yield losses due to gummy stem blight reached 19.2% and chemical control reduced disease levels significantly.

  7. Functional relationships of leafing intensity to plant height, growth form and leaf habit

    Science.gov (United States)

    Yan, En-Rong; Milla, Rubén; Aarssen, Lonnie W.; Wang, Xi-Hua

    2012-05-01

    Leafing intensity, i.e. the number of leaves per unit of stem volume or mass, is a common developmental correlate of leaf size. However, the ecological significance and the functional implications of variation in leafing intensity, other than its relation to leaf size, are unknown. Here, we explore its relationships with plant height, growth form, leaf size, and leaf habit to test a series of corollaries derived from the leafing intensity premium hypothesis. Volume-based leafing intensities and plant heights were recorded for 109 woody species from the subtropical evergreen broadleaf forests of eastern China. In addition, we compiled leafing intensity data from published literature, and combined it with our data to form a 398 species dataset, to test for differences of leafing intensity between plant growth forms (i.e. herbaceous and woody) and leaf habits (i.e. deciduous and evergreens). Leafing intensity was negatively correlated with plant height and individual leaf mass. Volume-based leafing intensities were significantly higher in herbaceous species than in woody species, and also higher in deciduous than in evergreen woody species. In conclusion, leafing intensity relates strongly to plant height, growth form, leaf size, and leaf habit in directions generally in accordance to the leafing intensity premium hypothesis. These results can be interpreted in terms of the evolution of adaptive strategies involving response to herbivory, competitive ability for light and reproductive economy.

  8. Effect of meteorological factors on the development of lentil stemphylium blight at different sowing dates in rampur, chitwan, Nepal

    Directory of Open Access Journals (Sweden)

    Subash Subedi

    2016-04-01

    Full Text Available Stemphylium species are pathogenic to a number of crops under broad geography and diverse environments. Stemphylium blight of lentil (Lens culinaris Medik caused by Stemphylium botryosum Walr is becoming a serious emerging threat to lentil cultivation and become widespread throughout major legume growing areas in Nepal. Lentil was sown in different dates to observed incidence and severity of stemphylium blight in Rampur, Chitwan during two consecutive years 2012-2014. Lentil seeds sown up to middle of November escaped the disease severity and also resulted higher yield compared to other dates. Disease severity increased with the advancement of sowing date from November 1 to December 21 with decreased yields. The trends of disease development were similar in both years. The maximum and minimum temperatures, total rainfall and sunshine hour ranging from 22.42-24.23°C (mean 23.32°C, 4.12-13.00°C(mean 8.56°C, 9.6-30.5mm (mean 24.85mm and 200.05-309.85 hour (mean 254.95 hour respectively were favorable for disease development. A multiple linear regression model with temperature, rainfall and sunshine hours was developed to predict stemphylium blight disease severity on lentil plants.

  9. Potential for the integration of biological and chemical control of sheath blight disease caused by Rhizoctonia solani on rice.

    Science.gov (United States)

    Boukaew, Sawai; Klinmanee, Chanasirin; Prasertsan, Poonsuk

    2013-10-01

    Biological control using antagonistic microbes to minimize the use of chemical pesticides has recently become more prevalent. In an attempt to find an integrated control system for sheath blight, caused by Rhizoctonia solani in rice, Streptomyces philanthi RM-1-138, commercial formulations of Bacillus subtilis as Larminar® and B. subtilis strain NSRS 89-24+MK-007 as Biobest® and chemical fungicides including carbendazim®, validamycin®, propiconazole® and mancozeb® were applied alone and in combination with S. philanthi RM-1-138. In vitro experiments showed that all treatments tested did provide some control against mycelial growth and sclerotia production by R. solani PTRRS-9. In addition, the four chemical fungicides had no detrimental effects on S. philanthi RM-1-138 even at high concentrations (up to 100 μg/ml). The efficacy of S. philanthi RM-1-138, the commercial formulations of B. subtilis, chemical fungicides alone or in combination with S. philanthi RM-1-138 was also tested in a greenhouse experiment against sheath blight disease on rice plants. All treatments showed some protection of rice for sheath blight by 47-60 % when carbendazim® was applied alone and up to 74 % when combined with S. philanthi RM-1-138. PMID:23653261

  10. Sources of resistance in chickpea (cicer arietinum l.) land races against ascochyta rabiei causal agent of ascochyta blight disease

    International Nuclear Information System (INIS)

    Ascochyta blight disease, caused by the fungus Ascochyta rabiei, is a major yield limiting factor of chickpea in Turkey and around the world. This study was conducted to identify sources of genetic resistance against chickpea blight caused by Ascochyta rabiei. For this purpose, 68 chickpea land races of different origins were evaluated in both field and growth chamber conditions during 2008-2009 growing seassons. Two standard cultivars were used as a reference, Inci (resistant) and Canitez (susceptible). Disease severity scoring was conducted on a 1-9 rating scale 21 days after inoculation in growth chamber test and at flowering and pot filling stages in field tests. Analysis of variance (ANOVA) test showed a significant difference among the chickpea landraces in ascochyta blight resistance at p<0.05. None of the chickpea land races was highly resistant to the pathogen in growth chamber and field conditions. Only two landraces (10A and 28B) were moderately resistant to the disease. Some of the landraces resulted in a particular plant to exhibit no disease symptoms, indicating that the variation within chickpea land races was high. Therefore, seeds of this plant were harvested separately and preserved for further evaluations. (author)

  11. Control of plant defense mechanisms and fire blight pathogenesis through the regulation of 6-thioguanine biosynthesis in Erwinia amylovora.

    Science.gov (United States)

    Coyne, Sébastien; Litomska, Agnieszka; Chizzali, Cornelia; Khalil, Mohammed N A; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

    2014-02-10

    Fire blight is a devastating disease of Rosaceae plants, such as apple and pear trees. It is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium Erwinia amylovora. The plant pathogen produces the well-known antimetabolite 6-thioguanine (6TG), which plays a key role in fire blight pathogenesis. Here we report that YcfR, a member of the LTTR family, is a major regulator of 6TG biosynthesis in E. amylovora. Inactivation of the regulator gene (ycfR) led to dramatically decreased 6TG production. Infection assays with apple plants (Malus domestica cultivar Holsteiner Cox) and cell cultures of Sorbus aucuparia (mountain ash, rowan) revealed abortive fire blight pathogenesis and reduced plant response (biphenyl and dibenzofuran phytoalexin production). In the presence of the ΔycfR mutant, apple trees were capable of activating the abscission machinery to remove infected tissue. In addition to unveiling the regulation of 6TG biosynthesis in a major plant pathogen, we demonstrate for the first time that this antimetabolite plays a pivotal role in dysregulating the plant response to infection.

  12. The Differences among Pear Genotypes to Fire Blight (Erwinia amylovora Attack, Based on Observations of Natural Infection

    Directory of Open Access Journals (Sweden)

    Adriana F. SESTRAS

    2008-08-01

    Full Text Available Fire blight, caused by the bacterium Erwinia amylovora, is one of the most damaging diseases of pear in the world. In Cluj-Napoca area, situated in central Transylvania, Romania, fire blight was observed first in 1994, very late comparative with the other countries from occidental Europe. The response of the pear cultivars and species from National Pear Collection from Cluj-Napoca to fire blight attack, assessed in natural conditions of infection, range on a large scale of variability, which denotes a strong influence of the genotype in expression of resistance or sensitivity to disease. From all genotypes, about 20.5% have not presented symptoms of attack, among them being the following: 'Blanquet precoce', 'Klementinka', 'Severianka', 'Beurre Bachelier', 'Kieffer Seedling', 'Er Shi Shinge', 'Beurre Amanlis', 'Bristol Cross', 'Beurre Liegel', 'Beurre Lucon', 'Grand Champion', 'Magness', 'Mericourt' etc. and several ancient autochthonous cultivars ('Pere malaiete', 'De zahar de Bihor', 'Cu miez rosu', 'Clopotele', 'Garoafa mare', 'Craiese', 'Para de apa'. Also, there were identified several species of Pyrus with no attack, as P. pollveria, P. common pear, P. lindlezi, P. malifolia, P. persica, P. ussuriensis, P. variolosa. The remarked genotypes could be potential sources for further breeding programmes and increase the number of genotypes available for breeding new pear cultivars resistant to Erwinia attack.

  13. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach that ...

  14. Analysis of Peanut Leaf Proteome

    DEFF Research Database (Denmark)

    Ramesh, R.; Suravajhala, Prashanth; Pechan, T.

    2010-01-01

    approach to define function of their associated genes. Proteome analysis linked to genome sequence information is critical for functional genomics. However, the available protein expression data is extremely inadequate. Proteome analysis of peanut leaf was conducted using two-dimensional gel...... electrophoresis in combination with sequence identification using MALDI/TOF to determine their identity and function related to growth, development and responses to stresses. Peanut leaf proteins were resolved into 300 polypeptides with pI values between 3.5 and 8.0 and relative molecular masses from 12 to 100 k......Da. A master leaf polypeptide profile was generated based on the consistently expressed protein pattern. Proteins present in 205 spots were identified using GPS software and Viridiplantae database (NCBI). Identity of some of these proteins included RuBisCO, glutamine synthetase, glyoxisomal malate...

  15. Sgt1, but not Rar1, is essential for the RB-mediated broad-spectrum resistance to potato late blight

    Directory of Open Access Journals (Sweden)

    Wielgus Susan M

    2008-01-01

    Full Text Available Abstract Background Late blight is the most serious potato disease world-wide. The most effective and environmentally sound way for controlling late blight is to incorporate natural resistance into potato cultivars. Several late blight resistance genes have been cloned recently. However, there is almost no information available about the resistance pathways mediated by any of those genes. Results We previously cloned a late blight resistance gene, RB, from a diploid wild potato species Solanum bulbocastanum. Transgenic potato lines containing a single RB gene showed a rate-limiting resistance against all known races of Phytophthora infestans, the late blight pathogen. To better understand the RB-mediated resistance we silenced the potato Rar1 and Sgt1 genes that have been implicated in mediating disease resistance responses against various plant pathogens and pests. The Rar1 and Sgt1 genes of a RB-containing potato clone were silenced using a RNA interference (RNAi-based approach. All of the silenced potato plants displayed phenotypically normal growth. The late blight resistance of the Rar1 and Sgt1 silenced lines were evaluated by a traditional greenhouse inoculation method and quantified using a GFP-tagged P. infestans strain. The resistance of the Rar1-silenced plants was not affected. However, silencing of the Sgt1 gene abolished the RB-mediated resistance. Conclusion Our study shows that silencing of the Sgt1 gene in potato does not result in lethality. However, the Sgt1 gene is essential for the RB-mediated late blight resistance. In contrast, the Rar1 gene is not required for RB-mediated resistance. These results provide additional evidence for the universal role of the Sgt1 gene in various R gene-mediated plant defense responses.

  16. Control of fire blight (Erwinia amylovora on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

    Directory of Open Access Journals (Sweden)

    Srđan G. Aćimović

    2015-02-01

    Full Text Available Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH or acibenzolar-S-methyl (ASM, significant reduction of blossom and shoot blight symptoms was observed compared to water- or non-injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2 and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control.

  17. 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

  18. 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

  19. Effect of nitrogen supply on leaf appearance, leaf growth, leaf nitrogen economy and photosynthetic capacity in maize (Zea mays L.)

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.; Birch, C.J.

    2005-01-01

    Leaf area growth and nitrogen concentration per unit leaf area, Na (g m-2 N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain Na and photosynthetic capacity per unit leaf area. This paper

  20. Fire Blight Control: The Struggle Goes On. A Comparison of Different Fire Blight Control Methods in Switzerland with Respect to Biosafety, Efficacy and Durability

    Directory of Open Access Journals (Sweden)

    Michele Gusberti

    2015-09-01

    Full Text Available Fire blight (FB, caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable level in years of heavy disease pressure. The Swiss authorities therefore currently allow the controlled use of the antibiotic streptomycin against FB in years that are predicted to have heavy infection periods, but only one treatment per season is permitted. Another strategy for controlling Erwinia is to breed resistant/tolerant apple cultivars. One way of accelerating the breeding process is to obtain resistant cultivars by inserting one or several major resistance genes, using genetic engineering. To date, no study summarizing the impact of different FB control measures on the environment and on human health has been performed. This study consequently aims to compare different disease-control measures (biological control, chemical control, control by antibiotics and by resistant/tolerant apple cultivars obtained through conventional or molecular breeding applied against E. amylovora, considering different protection goals (protection of human health, environment, agricultural diversity and economic interest, with special emphasis on biosafety aspects. Information on each FB control measure in relation to the specified protection goal was assessed by literature searches and by interviews with experts. Based on our results it can be concluded that the FB control measures currently applied in Switzerland are safe for consumers, workers and the environment. However, there are several gaps in our knowledge of the human health and environmental impacts analyzed: data are missing (1 on long term studies on the efficacy of most of the analyzed FB control measures; (2 on the safety of operators handling streptomycin; (3 on residue analyses of Equisetum plant extract, the copper

  1. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  2. Analysis of Circadian Leaf Movements.

    Science.gov (United States)

    Müller, Niels A; Jiménez-Gómez, José M

    2016-01-01

    The circadian clock is a molecular timekeeper that controls a wide variety of biological processes. In plants, clock outputs range from the molecular level, with rhythmic gene expression and metabolite content, to physiological processes such as stomatal conductance or leaf movements. Any of these outputs can be used as markers to monitor the state of the circadian clock. In the model plant Arabidopsis thaliana, much of the current knowledge about the clock has been gained from time course experiments profiling expression of endogenous genes or reporter constructs regulated by the circadian clock. Since these methods require labor-intensive sample preparation or transformation, monitoring leaf movements is an interesting alternative, especially in non-model species and for natural variation studies. Technological improvements both in digital photography and image analysis allow cheap and easy monitoring of circadian leaf movements. In this chapter we present a protocol that uses an autonomous point and shoot camera and free software to monitor circadian leaf movements in tomato. PMID:26867616

  3. A method to improve leaf succulence quantification

    OpenAIRE

    André Mantovani

    1999-01-01

    Leaf succulence has important physiological and ecological implications. Currently it is quantified by Delf's index (fresh weight/leaf area) and fresh weight/ dry weight ratio. Both indeces are reconsidered and a new index is proposed. Shade and sun leaves from terrestrial, hemiepiphytic and epiphytic aroids were studied. Delf's formula, which does not consider dry weight, overestimated leaf succulence. As fresh weight / dry weight ratio (fw / dw) does not consider leaf area, plants with the ...

  4. Evidence of horizontal gene transfer between obligate leaf nodule symbionts.

    Science.gov (United States)

    Pinto-Carbó, Marta; Sieber, Simon; Dessein, Steven; Wicker, Thomas; Verstraete, Brecht; Gademann, Karl; Eberl, Leo; Carlier, Aurelien

    2016-09-01

    Bacteria of the genus Burkholderia establish an obligate symbiosis with plant species of the Rubiaceae and Primulaceae families. The bacteria, housed within the leaves, are transmitted hereditarily and have not yet been cultured. We have sequenced and compared the genomes of eight bacterial leaf nodule symbionts of the Rubiaceae plant family. All of the genomes exhibit features consistent with genome erosion. Genes potentially involved in the biosynthesis of kirkamide, an insecticidal C7N aminocyclitol, are conserved in most Rubiaceae symbionts. However, some have partially lost the kirkamide pathway due to genome erosion and are unable to synthesize the compound. Kirkamide synthesis is therefore not responsible for the obligate nature of the symbiosis. More importantly, we find evidence of intra-clade horizontal gene transfer (HGT) events affecting genes of the secondary metabolism. This indicates that substantial gene flow can occur at the early stages following host restriction in leaf nodule symbioses. We propose that host-switching events and plasmid conjugative transfers could have promoted these HGTs. This genomic analysis of leaf nodule symbionts gives, for the first time, new insights in the genome evolution of obligate symbionts in their early stages of the association with plants. PMID:26978165

  5. 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)

  6. 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...

  7. 7 CFR 29.2278 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2351.)...

  8. 7 CFR 29.2530 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2530 Section 29.2530 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2601.)...

  9. 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...

  10. 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....

  11. 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....

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Nonchemical pest control in China rice: a review

    OpenAIRE

    Huang, Shiwen; Wang, Ling; Liu, Lianmeng; Fu, Qian; Zhu, Defeng

    2014-01-01

    Major pests such as blast, sheath blight, bacterial blight, plant hoppers, leaf folder, and stem borers occur in rice paddy fields. These pests cause high damage to the grain and straw yield. The application of high N fertilizer loads increases the predisposition of rice crops to be infected by pests. Many agrochemicals used to control pests lead to pest adaptation and resistance, loss of soil fertility and organic carbon, soil erosion, decreasing biodiversity, and desertification. Chemical f...

  17. Combining ability for Fusarium head blight resistance in wheat (Triticum aestivum L.

    Directory of Open Access Journals (Sweden)

    Subas Malla

    2010-12-01

    Full Text Available Fusarium head blight (FHB caused by Fusarium graminearum reduces wheat (Triticum aestivum L. em. Thell grain yield and end-use quality worldwide. Three each of FHB susceptible (‘Nekota’, ‘2137’, and ‘Harding’ and resistant (‘Ning 7840’, ‘ND2710’ and ‘BacUp’ parents were included in a partial diallel mating design (Griffing’s Method 4, Model 1. The F4:5 progeny was evaluated for healthy index, undamaged kernels, and deoxynivalenol (DON content following artificial inoculation and mist-irrigation in 2006 and 2007. General combining ability (GCA was highly significant (P < 0.01 for healthy index; whereas specific combining ability (SCA and GCA-by-year interaction were not significant. The combining ability ratio and narrow-sense heritability were 0.95 and 0.83, respectively. The Genotype, Genotype-by-Environment (GGE biplot analysis showed that the ND2710/BacUp combination had the best healthy index and undamaged kernels; whereas Ning 7840 contributed resistance to DON accumulation. The results indicated additive gene effects mainly control that healthy index. Thus, genetic gain in developing resistance in wheat can be achieved through selection.

  18. In vitro induction of variation through radiation for late blight resistance and heat tolerance in potato

    International Nuclear Information System (INIS)

    In vitro plants were obtained from nodal sections of sprouts of cvs. 'Kufri Jyoti' and 'Kufri Chandramukhi' of potato cultured on MS medium with 3% sucrose. Callus from leaves of in vitro cultured plantlets was induced on modified Linsmaier and Skoog medium supplemented with 5 mg/1 NAA. The obtained shoots and calli were irradiated with 20 and 40 Gy gamma rays. Irradiatied shoots were transferred to MS medium with 8% sucrose for multiplication, and then to MS medium with 8% sucrose and 10 mg/1 BAP to induce microtuber formation, which gave on average 1.3 microtubers per plant. The microtubers were planted in pots and variation was observed in plant morphology and tuber characters. To study variation for late blight resistance, irradiated calli were kept on Gamborg B-5 medium with culture filtrate of Phytophthora infestans. To induce variation for heat tolerance, in vitro shoots from irradiated material were mass-propagated and allowed to produce microtubers at high temperature. (author). 3 refs, 3 tabs

  19. Advances in Mapping Loci Conferring Resistance to Rice Sheath Blight and Mining Rhizoctonia solani Resistant Resources

    Institute of Scientific and Technical Information of China (English)

    ZENG Yu-xiang; JI Zhi-juan; MA Liang-yong; LI Xi-ming; YANG Chang-deng

    2011-01-01

    Sheath blight (SB) caused by Rhizoctonia solani is one of the three major diseases of rice,and now has become the most severe disease causing rice yield loss in China.Breeding and use of varieties resistant to SB is crucial in controlling the disease,but the advances achieved have been limited due to the lack of highly SB-resistant rice germplasm.Genetic analysis revealed that the SB resistance in rice was a typical quantitative trait controlled by multi-genes.Although many QTLs conferring resistance to SB have been identified in recent years,most of the QTLs only showed small effects and few of them have been evaluated for utilization potential.Many R.solani-resistant resources have been found in wild rice species,microorganisms and other plant species.It is already known that the SB-resistance could be improved in transgenic rice plants by genetic transformation.This paper reviewed the genetic mapping of loci associated with resistance to rice SB,the evaluation of the potential of resistance QTLs,and the resistant resources found in various organisms besides rice.To develop SB-resistant rice varieties,it is important to develop and explore new resistant rice germplasms,fine map and evaluate resistance QTLs,and also to pay attention to various bio-resources showing resistance to R.solani.

  20. A method for the rapid detection and identification of halo blight pathogen on common bean

    Directory of Open Access Journals (Sweden)

    Popović Tatjana

    2014-01-01

    Full Text Available A diagnostic method based on nested-PCR, followed by ELISA and conventional bacteriology tests, for the rapid and reliable detection of halo blight pathogen Pseudomonas savastanoi pv. phaseolicola (Psp collected from infected bean leaves and seeds is described. Psp formed white, small and flat colonies on nutrient agar medium, creamy white, flat and circular on Milk-Tween agar medium and light yellow, convex and shiny on modified sucrose peptone agar medium. Eighteen Gram-negative, catalase-positive and oxidase-negative strains were subjected to nested PCR with primers P 5.1/P 3.1 and P 5.2/P 3.2, which directed the amplification of the 450 bp target DNA fragment in all tested strains. According to the results of DAS- and PTA-ELISA with respect to reactivity to specific antibodies, all analyzed strains belonged to Psp bacterium. Pathogenicity was tested on bean pods and cotyledon leaves, on which greasy spots were formed. Psp did not cause hypersensitive reaction on the leaves of tobacco and geranium. Strains produced levan, fluorescent pigment, oxidative metabolism of glucose, did not reduce nitrate, did not produce indole and H2S, did not hydrolyze starch, gelatin and esculin; they produced acid from glucose, mannose, sucrose and glycerol, and did not produce acid from maltose, starch, esculin, dulcite, sorbitol, inositol and erythritol.

  1. BIS(4-FLUOROPHENYLSULFONYLDITHIOCARBIMATOZINCATE(II SALTS: NEW ANTIFUNGALS FOR THE CONTROL OF Botrytis BLIGHT

    Directory of Open Access Journals (Sweden)

    Alexandre A. Oliveira

    2015-07-01

    Full Text Available Botrytis blight or gray mold is a highly destructive disease caused by Botrytis spp., that infects flowers, trees vegetables, fruit, especially grapevines and strawberry. Three new compounds with general formula (A2[Zn(4-FC6H4SO2N=CS22], where A = PPh3CH3 (2a, PPh3C2H5 (2b, PPh3C4H9 (2c, and the previously published compounds where A = PPh4 (2d and NBu4 (2e, were synthesized by the reaction of 4-fluorophenylsulfonyldithiocarbimate potassium dihydrate and zinc(II acetate dihydrate with the appropriate counter cations (A halides. The new compounds were characterized by infrared, 1H and 13C NMR spectroscopies. All these salts inhibited the growth of Botrytis cinerea, with compounds 2c and 2d showing greater antifungal activity than zinc dimethyldithiocarbamate, the active principle of the fungicide Ziram. The bis(dithiocarbimatezincate(II salts are also active against the bacteria Escherichia coli and Staphylococcus aureus.

  2. Characterization of a Viral EPS-Depolymerase, a Potential Tool for Control of Fire Blight.

    Science.gov (United States)

    Kim, W S; Geider, K

    2000-11-01

    ABSTRACT A 3.3-kb fragment of genomic DNA from bacteriophage Phi-Ea1h encoding an amylovoran-directed depolymerase lyase was sequenced, and three open reading frames (ORFs) were detected. The first ORF could encode a lysozyme and the second a holin that may form a pore supporting cell lysis by the lysozyme. The third ORF encodes a protein of 657 amino acids and deletion mutation in this DNA fragment abolished extracellular polysaccharide (EPS)-degrading activity. A putative promoter and a ribosome binding sequence were located in front of the gene. A polymerase chain reaction product spanning the gene was inserted into multi copy plasmids including fusions with a Histidine-tagged sequence to facilitate its purification on a nickel nitrilotriacetic acid column. Maximal activity of the purified protein was observed between pH 4 and 5 at 52 degrees C. Visualized by staining with fluorescein isothiocyanate-labeled lectin from Abrus precatorious, the enzyme degraded the EPS-capsules of Erwina amylovora. In virulence assays, no symptoms were detected for a low inoculum of an E. amylovora strain when pear slices were soaked in a solution of depolymerase in contrast to control slices without addition of the enzyme. Furthermore, gfp- or lux-labeled E. amylovora cells were not propagated, when their amylovoran capsules were removed by the depolymerase. The enzyme could be a tool for biological control of fire blight.

  3. Screening of ten advanced chickpea lines for blight and wilt resistance

    International Nuclear Information System (INIS)

    Ten advanced chickpea lines developed at NIAB were screened for resistance to Ascochyta blight and Fusarium wilt diseases in different sets of experiments conducted under controlled environment. Inoculation of plants by spore suspension of virulent strains of Ascochyta rabiei revealed that one line (97313) was resistant tolerant, two lines (97305, 97392) were tolerant, six lines (97306, 97310, 97311, 97303, 97302, 97393) were tolerant/susceptible and one line (97301) was susceptible. Screening of the same lines against Fusarium wilt by water culture method showed that two lines (97301, 97313) were moderately resistant, four lines (97302, 97303, 97306, 97393) were tolerant and the remaining four lines were susceptible. Screening through phytotoxic culture filtrates revealed that two lines (97302, 97313) were less sensitive to culture filtrates of Ascochyta rabiei and Fusarium oxysporum than the resistant check (CM88). These lines were also analyzed spectrophotometrically for peroxidase enzyme activity. Maximum enzyme activity was detected after 48 hours of inoculation with A. rabiei in three lines (97305, 97311, 97313) and resistant check (CM88) while enzyme activity in the remaining lines reached its maximum after 72 hours of inoculation which was comparable to the susceptible check (Pb-1). These studies lead to the conclusion that one line (97313) exhibited resistance against both the diseases and can be used as a source of resistance for further improvement of chickpea germplasm. (author)

  4. Exploiting selective genotyping to study genetic diversity of resistance to Fusarium head blight in barley.

    Science.gov (United States)

    Wingbermuehle, W J; Gustus, C; Smith, K P

    2004-10-01

    Numerous barley cultivars from around the world have been identified as potential sources of Fusarium head blight (FHB) resistance genes. All of these cultivars exhibit partial resistance, and several mapping studies have shown that resistance to FHB is controlled by multiple genes. Successful development of barley cultivars with high levels of FHB resistance will require combining genes from multiple sources. We characterized five potential new sources of FHB resistance ('AC Oxbow', 'Atahualpa', 'HOR211', 'PFC88209', and 'Zhedar#1') to determine if they contain new FHB resistance genes. Cluster analysis, using a set of 80 SSR markers distributed throughout the genome, showed that most of the new sources of resistance were not similar to three cultivars that have been used in previous FHB mapping studies ('Chevron', 'Frederickson', and 'Gobernadora'), with 'Atahualpa' and 'HOR211' being the most dissimilar. By selective genotyping, we determined whether markers linked to six known FHB resistance quantitative trait loci (QTLs), discovered in other genotypes, explained variation for resistance in advanced breeding populations created from the new sources of resistance. Markers linked to four of the six known QTLs were associated with FHB severity in at least one of the populations. However, none of the six QTL regions were associated with variation for FHB severity in populations derived from crosses that utilized sources of resistance HOR211 or PFC88209. Selective genotyping is an efficient method for breeders to utilize current QTL information about disease resistance to search for new resistance genes. PMID:15257434

  5. PHYSICAL, MORPHOLOGICAL PROPERTIES AND RAMAN SPECTROSCOPY OF CHESTNUT BLIGHT DISEASED CASTANEA SATIVA MILL. WOOD

    Directory of Open Access Journals (Sweden)

    Gokhan Gunduz

    2016-03-01

    Full Text Available In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD wood were investigated, and the study also included observations using Raman spectroscopy. The objective of these investigations was to determine the extent of the damage that is done to the wood of the diseased chestnut trees, which must be removed from the forest and used in the manufacture of industrial products. It was indicated that most of the adverse effects of the disease were in the vascular cambium. There was a clear indication of deterioration of the wood in the last growth ring next to vascular cambium. In the diseased secondary xylem region next to vascular cambium; vessel diameter, vessel frequency and vessel element length had a decrease, and vessel and other cells were irregular compared to healthy wood. Spores were detected and identified as Cryphonectria parasitica (Murrill. Annual ring properties (annual growth ring width, latewood percentage, etc. were similar in diseased wood compared to healthy wood. The Raman spectroscopy results showed no significant changes in the structure of the cell wall or its components. After removing the diseased parts, unlimited usage of formerly wood is possible. Heat treatment of the wood is suggested before use in the interest of sanitation and dimensional stability.

  6. Transcriptome Analysis Reveals Candidate Genes involved in Blister Blight defense in Tea (Camellia sinensis (L) Kuntze).

    Science.gov (United States)

    Jayaswall, Kuldip; Mahajan, Pallavi; Singh, Gagandeep; Parmar, Rajni; Seth, Romit; Raina, Aparnashree; Swarnkar, Mohit Kumar; Singh, Anil Kumar; Shankar, Ravi; Sharma, Ram Kumar

    2016-01-01

    To unravel the molecular mechanism of defense against blister blight (BB) disease caused by an obligate biotrophic fungus, Exobasidium vexans, transcriptome of BB interaction with resistance and susceptible tea genotypes was analysed through RNA-seq using Illumina GAIIx at four different stages during ~20-day disease cycle. Approximately 69 million high quality reads were assembled de novo, yielding 37,790 unique transcripts with more than 55% being functionally annotated. Differentially expressed, 149 defense related transcripts/genes, namely defense related enzymes, resistance genes, multidrug resistant transporters, transcription factors, retrotransposons, metacaspases and chaperons were observed in RG, suggesting their role in defending against BB. Being present in the major hub, putative master regulators among these candidates were identified from predetermined protein-protein interaction network of Arabidopsis thaliana. Further, confirmation of abundant expression of well-known RPM1, RPS2 and RPP13 in quantitative Real Time PCR indicates salicylic acid and jasmonic acid, possibly induce synthesis of antimicrobial compounds, required to overcome the virulence of E. vexans. Compendiously, the current study provides a comprehensive gene expression and insights into the molecular mechanism of tea defense against BB to serve as a resource for unravelling the possible regulatory mechanism of immunity against various biotic stresses in tea and other crops. PMID:27465480

  7. Transcriptome Analysis Reveals Candidate Genes involved in Blister Blight defense in Tea (Camellia sinensis (L) Kuntze)

    Science.gov (United States)

    Jayaswall, Kuldip; Mahajan, Pallavi; Singh, Gagandeep; Parmar, Rajni; Seth, Romit; Raina, Aparnashree; Swarnkar, Mohit Kumar; Singh, Anil Kumar; Shankar, Ravi; Sharma, Ram Kumar

    2016-07-01

    To unravel the molecular mechanism of defense against blister blight (BB) disease caused by an obligate biotrophic fungus, Exobasidium vexans, transcriptome of BB interaction with resistance and susceptible tea genotypes was analysed through RNA-seq using Illumina GAIIx at four different stages during ~20-day disease cycle. Approximately 69 million high quality reads were assembled de novo, yielding 37,790 unique transcripts with more than 55% being functionally annotated. Differentially expressed, 149 defense related transcripts/genes, namely defense related enzymes, resistance genes, multidrug resistant transporters, transcription factors, retrotransposons, metacaspases and chaperons were observed in RG, suggesting their role in defending against BB. Being present in the major hub, putative master regulators among these candidates were identified from predetermined protein-protein interaction network of Arabidopsis thaliana. Further, confirmation of abundant expression of well-known RPM1, RPS2 and RPP13 in quantitative Real Time PCR indicates salicylic acid and jasmonic acid, possibly induce synthesis of antimicrobial compounds, required to overcome the virulence of E. vexans. Compendiously, the current study provides a comprehensive gene expression and insights into the molecular mechanism of tea defense against BB to serve as a resource for unravelling the possible regulatory mechanism of immunity against various biotic stresses in tea and other crops.

  8. Leaf spring assembly for wheel suspension

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, K.; Mishima, Y.; Kuwayama, K.

    1986-09-16

    This patent describes a leaf spring assembly which consists of: a longitudinal leaf spring made of fiber reinforced plastics having a first surface to be applied with a tension force and a second surface to be applied with a compression force, the first surface of the leaf spring being a flat surface, and the second surface of the leaf spring being provided with a protrusion located substantially at the central portion of the leaf spring. The protrusion is made of a number of laminated short fibrous sheet-like materials saturated with synthetic resin, the short fibrous sheet-like materials of the protrusion being laminated independently and separately from reinforcement fibrous sheet-like materials in the leaf spring; a pair of pad members of elastic material attached to the first and second surfaces of the leaf spring; a pair of retainer plates attached to the first and second surfaces of the leaf spring through the pad members, one of the retainer plates being formed with an indented portion coupled with the protrusion of the leaf spring through one of the pad members without any clearance to clamp the leaf spring at its central portion and being further provided with a pair of protruded portions which are arranged adjacent to the indented portion to retain the paid member in place by engagement therewith; and means for clamping the retainer plates to the leaf spring and mounting the same on an axle housing.

  9. 山地延迟番茄晚疫病的发生与防治%Occurrence and Prevention of Delay Tomato Late Blight in Mountainous Region

    Institute of Scientific and Technical Information of China (English)

    李景明

    2015-01-01

    Symptom expression,etiology,occurred conditions of tomato late blight were elabrated.Causes of the outbreak on tomato late blight were analyzed.And in view of the characteristics of tomato late blight,prevention measures were put forward,so as to provide reference for delay tomato growers to forecast and prevention of the disease in Qingzhen City.%阐述了番茄晚疫病症状表现尧病原尧发生条件,分析该病重发原因,并针对番茄晚疫病的危害特点,提出防治措施,以期为清镇市延迟番茄种植户预测和防治该病提供参考。

  10. Identification and Characterization of Botrytis Blossom Blight of Japanese Plums Caused by Botrytis cinerea and B. prunorum sp. nov. in Chile.

    Science.gov (United States)

    Ferrada, Enrique E; Latorre, Bernardo A; Zoffoli, Juan P; Castillo, Antonio

    2016-02-01

    Blossom blight is a destructive disease of plums (Prunus salicina) when humid and temperate weather conditions occur in Chile. Disease incidence ranging from 4 to 53% has been observed. Symptoms include light brown petal necrosis, starting as light brown mottles or V-shaped necrosis at the margins of the petals, progressing to the stamen and pistils. In this study, the etiology of blossom blight of plums was determined. High- and low-sporulating isolates of Botrytis were obtained consistently from blighted blossoms and apparently healthy flowers of plums. Based on colony morphology, conidial production and molecular phylogenetic analysis, these high- and low-sporulating isolates were identified as B. cinerea and B. prunorum sp. nov., respectively. Phylogenetic analysis of the genes glyceraldehyde 3-phosphate dehydrogenase (G3PDH), heat-shock protein 60 (HSP60), and DNA-dependent RNA polymerase subunit II (RPB2) grouped B. prunorum isolates in a single cluster, distantly from B. cinerea and other Botrytis species. The phylogenetic analysis of necrosis and ethylene-inducing protein (NEP1 and NEP2) genes corroborated these results. Analysis of the internal transcribed spacer region and large-subunit (26S) ribosomal DNA and detection of Boty and Flipper transposable elements, were not useful to differentiate between these Botrytis species. Both species were pathogenic on plum flowers and the fruit of plums, apples, and kiwifruits. However, B. prunorum was less virulent than B. cinerea. These pathogens were re-isolated from inoculated and diseased tissues; thus, Koch's postulates were fulfilled, confirming its role in blossom blight of plums. B. cinerea was predominant, suggesting that B. prunorum may play a secondary role in the epidemiology of blossom blight in plums in Chile. This study clearly demonstrated that the etiology of blossom blight of plums is caused by B. cinerea and B. prunorum, which constitute a species complex living in sympatry on plums and possibly

  11. Progress in Research on Leaf Blight of Wheat in China%我国小麦叶枯性病害研究进展

    Institute of Scientific and Technical Information of China (English)

    商鸿生; 王凤乐

    2001-01-01

    在我国引起小麦叶枯病的主要病原真菌种类有Bipolaris sorokiniana、Monographella nivalis、Alternaria triticina、Septoria tritici和Stagonospora nodorum等,均能造成冬小麦和春小麦严重减产。本文全面评述了自20世纪70年代以来我国关于小麦叶枯病的研究状况,重点介绍了病害分布、经济重要性、病原学、病害循环、流行因素、寄主抗病性和药剂防治等方面的重要进展。并进而讨论了存在问题和改进途径,以利于今后调整研究内容,规范研究方法,开展长远的基础性研究和组织重大技术攻关。

  12. QTL analysis of late blight resistance in a diploid potato family of Solanum phureja x S. stenotomum.

    Science.gov (United States)

    Costanzo, S; Simko, I; Christ, B J; Haynes, K G

    2005-08-01

    Field resistance to Phytophthora infestans (Mont.) de Bary, the causal agent of late blight in potatoes, has been characterized in a potato segregating family of 230 full-sib progenies derived from a cross between two hybrid Solanum phureja x S. stenotomum clones. The distribution of area under the disease progress curve values, measured in different years and locations, was consistent with the inheritance of multigenic resistance. Relatively high levels of resistance and transgressive segregations were also observed within this family. A genetic linkage map of this population was constructed with the intent of mapping quantitative trait loci (QTLs) associated with this late blight field resistance. A total of 132 clones from this family were genotyped based on 162 restriction fragment length polymorphism (RFLP) markers. The genome coverage by the map (855.2 cM) is estimated to be at least 70% and includes 112 segregating RFLP markers and two phenotypic markers, with an average distance of 7.7 cM between two markers. Two methods were employed to determine trait-marker association, the non-parametric Kruskal-Wallis test and interval mapping analysis. Three major QTLs were detected on linkage group III, V, and XI, explaining 23, 17, and 10%, respectively, of the total phenotypic variation. The present study revealed the presence of potentially new genetic loci in this diploid potato family contributing to general resistance against late blight. The identification of these QTLs represents the first step toward their introgression into cultivated tetraploid potato cultivars through marker-assisted selection. PMID:15931506

  13. Control Methods for Potato Late Blight and Improvement Measures%马铃薯晚疫病综合防治方法及改进措施

    Institute of Scientific and Technical Information of China (English)

    李永国; 王志伟

    2012-01-01

    The symptoms, charafLerisLics, causing factors of potato late blight were introduced; and the comprehensive control method was put forward. Improvement measures were also proposed for existing problems in controlling patato late blight.%介绍了马铃薯晚疫病的症状、特点、影响发病的因素,并提出了综合防治方法,针对马铃薯晚疫病防治过程中存在的问题提出了改进措施

  14. Study of Investigation and Irulence Differentiation for Chestnut Blight%板栗疫病的调查和致病力分化研究概况

    Institute of Scientific and Technical Information of China (English)

    吴兆荣

    2013-01-01

    The occurrence law of chestnut blight was introduced, the investigation method was elaborated. The pathogenesis of chestnut blight was studied with two dimensional gel electrophore method. From the perspective of proteomics, irulence differentiation was studied%介绍了板栗疫病的发生规律,论述了板栗疫病的调查方法,探讨了双向凝胶电泳法研究板栗疫病菌的致病机理,并从蛋白质组学角度介绍了板栗疫病菌致病力分化的研究.

  15. Molecular and physiological properties of bacteriophages from North America and Germany affecting the fire blight pathogen Erwinia amylovora

    OpenAIRE

    Müller, Ina; Lurz, Rudi; Kube, Michael; Quedenau, Claudia; Jelkmann, Wilhelm; Geider, Klaus

    2011-01-01

    Summary For possible control of fire blight affecting apple and pear trees, we characterized Erwinia amylovora phages from North America and Germany. The genome size determined by electron microscopy (EM) was confirmed by sequence data and major coat proteins were identified from gel bands by mass spectroscopy. By their morphology from EM data, φEa1h and φEa100 were assigned to the Podoviridae and φEa104 and φEa116 to the Myoviridae. Host ranges were essentially confined to E. amylovora, stra...

  16. Characteristics of Resistance to Rice Sheath Blight of Zhongda 2, a Transgenic Rice Line as Modified by Gene "RC24"

    Institute of Scientific and Technical Information of China (English)

    YUAN Hong-xu; XU Xin-ping; ZHANG Jian-zhong; GUO Jian-fu; LI Bao-jian

    2004-01-01

    The transgenic rice, Zhongda 2, which was genetically modified from an indica rice line Zhuxian B by rice chitinase gene (RC24), had high resistance to rice sheath blight (Rhizoctonia solani) in laboratory and a two-year field experiment. The pathogen could invade sheath of Zhongda 2 and induce symptoms of the disease. No difference was noted in time of penetration or incubation period between Zhongda 2 and non-transgenic rice control, Zhuxian B, but the hyphae lysate could be observed earlier five non-transgenic rice lines showed higher resistance than donor non-transgenic parents, but the resistance was different along with the different maternal parents.

  17. BIS(4-FLUOROPHENYLSULFONYLDITHIOCARBIMATO)ZINCATE(II) SALTS: NEW ANTIFUNGALS FOR THE CONTROL OF Botrytis BLIGHT

    OpenAIRE

    Oliveira, Alexandre A; Oliveira, Marcelo R. L.; Mayura M. M. Rubinger; Elisa L. Piló; Daniele C. Menezes; Laércio Zambolim

    2015-01-01

    Botrytis blight or gray mold is a highly destructive disease caused by Botrytis spp., that infects flowers, trees vegetables, fruit, especially grapevines and strawberry. Three new compounds with general formula (A)2[Zn(4-FC6H4SO2N=CS2)2], where A = PPh3CH3 (2a), PPh3C2H5 (2b), PPh3C4H9 (2c), and the previously published compounds where A = PPh4 (2d) and NBu4 (2e), were synthesized by the reaction of 4-fluorophenylsulfonyldithiocarbimate potassium dihydrate and zinc(II) acetate dihydrate with...

  18. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement.

    Science.gov (United States)

    Maloof, Julin N; Nozue, Kazunari; Mumbach, Maxwell R; Palmer, Christine M

    2013-01-01

    High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping. PMID:23380664

  19. The Influence of Leaf Angle and Leaf Surface Characteristics on the Process of Rainfall Interception

    Science.gov (United States)

    Holder, C.; Ginebra, R.; Webb, R.

    2015-12-01

    Individual choice in plant selection for household landscaping influences differences in runoff from urban watersheds because the variation in plant canopy architecture results in rainfall interception differences. Understanding the variables that influence rainfall interception and understanding the mechanism of rainfall interception are important concepts for sustainable watershed management. The broad objective of this study was to explore the influence of leaf hydrophobicity, water droplet retention, and leaf angle on the mechanism and process of rainfall interception and raindrop impaction on leaf surfaces of common tree species from the semi-arid regions of the western United States. Leaf hydrophobicity is determined by the cohesive forces of the water molecules among themselves and the adhesive forces that result from the molecular interactions between the water droplet and the leaf surface. Water droplet retention is a measure of how easily a water droplet drains off a leaf surface. The specific hypotheses examined were 1) larger raindrops falling on leaf surfaces will deflect the leaf to an angle greater than the water droplet retention angle; 2) an increased leaf angle, whether from natural position or deflection due to droplet impact and retention, reduces interception from raindrop impaction on hydrophobic and hydrophilic leaf surfaces; and 3) increased droplet size and frequency decrease rainfall interception more significantly in the hydrophilic case. These hypotheses were addressed in a laboratory experiment by 1) measuring leaf hydrophobicity and water droplet retention using a goniometer with a tilting base; 2) measuring leaf traits such as leaf area, leaf surface roughness, trichome density, and specific storage capacity; 3) examining raindrop splash on leaf surfaces with varying leaf hydrophobicity, water droplet retention, and leaf angle with a raindrop generator and high-speed video camera; and 4) modeling the impact of raindrop splash on leaf

  20. Antagonistic potential of Pseudomonas graminis 49M against Erwinia amylovora, the causal agent of fire blight.

    Science.gov (United States)

    Mikiciński, Artur; Sobiczewski, Piotr; Puławska, Joanna; Malusa, Eligio

    2016-08-01

    In a previous study (Mikiciński et al. in Eur J Plant Pathol, doi: 10.1007/s10658-015-0837-y , 2015), we described the characterization of novel strain 49M of Pseudomonas graminis, isolated from the phyllosphere of apple trees in Poland showing a good protective activity against fire blight on different organs of host plants. We now report investigations to clarify the basis for this activity. Strain 49M was found to produce siderophores on a medium containing complex CAS-Fe(3+) and HDTMA, but was not able to produce N-acyl homoserine lactones (AHLs). Moreover, it formed a biofilm on polystyrene and polyvinyl chloride (PVC) surfaces. Strain 49M gave a positive reaction in PCR with primers complementary to gacA, the regulatory gene influencing the production of several secondary metabolites including antibiotics. The genes prnD (encoding pyrrolnitrin), pltC, pltB (pyoluteorin), phlD (2,4-diacetyl-phloroglucinol) and phzC as well as phzD (and their homologs phzF and phzA encoding phenazine), described for antagonistic fluorescent pseudomonads, however, were not detected. Research into the biotic relationship between strain 49M and Erwinia amylovora strain Ea659 on five microbiological media showed that this strain clearly inhibited the growth of the pathogen on King's B and nutrient agar with glycerol media, to a very small extent on nutrient agar with sucrose, and not at all on Luria-Bertani agar. On medium 925, strain 49M even stimulated E. amylovora growth. The addition of ferric chloride to King's B resulted in the loss of its inhibitory ability. Testing the survival of 49M in vitro showed its resistance to drought, greater than that of E. amylovora. PMID:27002332