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Sample records for identified powdery mildew

  1. Resistance to Powdery Mildews

    DEFF Research Database (Denmark)

    Siwoszek, Agnieszka Izabela

    how the basic resistance components contribute to resistance against powdery mildews. Furthermore, I propose an alternative strategy of achieving resistance to barley powdery mildew by application of peptide aptamers. Peptide aptamers are small proteins selected to specifically target conserved Yx......C motif of barley powdery mildew effectors. I present a proof-of-concept study in Arabidopsis, where overexpression of peptide aptamers significantly reduced the susceptibility to barley powdery mildew. Moreover, I set the discovery in a bigger context by summarizing genetic engineering technologies...

  2. NMR Spectroscopy Identifies Metabolites Translocated from Powdery Mildew Resistant Rootstocks to Susceptible Watermelon Scions.

    Science.gov (United States)

    Mahmud, Iqbal; Kousik, Chandrasekar; Hassell, Richard; Chowdhury, Kamal; Boroujerdi, Arezue F

    2015-09-16

    Powdery mildew (PM) disease causes significant loss in watermelon. Due to the unavailability of a commercial watermelon variety that is resistant to PM, grafting susceptible cultivars on wild resistant rootstocks is being explored as a short-term management strategy to combat this disease. Nuclear magnetic resonance-based metabolic profiles of susceptible and resistant rootstocks of watermelon and their corresponding susceptible scions (Mickey Lee) were compared to screen for potential metabolites related to PM resistance using multivariate principal component analysis. Significant score plot differences between the susceptible and resistant groups were revealed through Mahalanobis distance analysis. Significantly different spectral buckets and their corresponding metabolites (including choline, fumarate, 5-hydroxyindole-3-acetate, and melatonin) have been identified quantitatively using multivariate loading plots and verified by volcano plot analyses. The data suggest that these metabolites were translocated from the powdery mildew resistant rootstocks to their corresponding powdery mildew susceptible scions and can be related to PM disease resistance.

  3. Grapevine powdery mildew resistance and susceptibility loci identified on a high-resolution SNP map.

    Science.gov (United States)

    Barba, Paola; Cadle-Davidson, Lance; Harriman, James; Glaubitz, Jeffrey C; Brooks, Siraprapa; Hyma, Katie; Reisch, Bruce

    2014-01-01

    Improved efficacy and durability of powdery mildew resistance can be enhanced via knowledge of the genetics of resistance and susceptibility coupled with the development of high-resolution maps to facilitate the stacking of multiple resistance genes and other desirable traits. We studied the inheritance of powdery mildew (Erysiphe necator) resistance and susceptibility of wild Vitis rupestris B38 and cultivated V. vinifera 'Chardonnay', finding evidence for quantitative variation. Molecular markers were identified using genotyping-by-sequencing, resulting in 16,833 single nucleotide polymorphisms (SNPs) based on alignment to the V. vinifera 'PN40024' reference genome sequence. With an average density of 36 SNPs/Mbp and uniform coverage of the genome, this 17K set was used to identify 11 SNPs on chromosome 7 associated with a resistance locus from V. rupestris B38 and ten SNPs on chromosome 9 associated with a locus for susceptibility from 'Chardonnay' using single marker association and linkage disequilibrium analysis. Linkage maps for V. rupestris B38 (1,146 SNPs) and 'Chardonnay' (1,215 SNPs) were constructed and used to corroborate the 'Chardonnay' locus named Sen1 (Susceptibility to Erysiphe necator 1), providing the first insight into the genetics of susceptibility to powdery mildew from V. vinifera. The identification of markers associated with a susceptibility locus in a V. vinifera background can be used for negative selection among breeding progenies. This work improves our understanding of the nature of powdery mildew resistance in V. rupestris B38 and 'Chardonnay', while applying next-generation sequencing tools to advance grapevine genomics and breeding.

  4. Resistance to Powdery Mildews

    DEFF Research Database (Denmark)

    Siwoszek, Agnieszka Izabela

    in majority of them. Resistance to barley powdery mildew in the field is controlled by use of resistant varieties in a combination with fungicides. Early disease management is crucial for effective control. Yet, the pathogen commonly develops fungicide resistance due to simple point mutations. Several studies...... investigated reduced fitness of plants as a cost of resistance to pathogens. In case of barley powdery mildew, most common resistance (mlo) is linked to a higher susceptibility to other pathogens and spontaneous necrosis that leads to yield reduction. Thus, there is a clear need for alternative methods of crop...... protection. In the present study, I provide an overview of the current knowledge about plant pathogens and plant disease resistance. I use Arabidopsis as a model to investigate the mechanism of non-host resistance, presumed to be the most durable and broad-spectrum form of resistance. I attempt to determine...

  5. Powdery Mildew Disease Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Somerville, Shauna C.

    2010-08-31

    The overall goal of this project was to characterize the PMR5 protein, a member of the DUF231/TBR family, and to determine its role in plant cell wall biogenesis. Since the pmr5 mutants are also resistant to the fungal powdery mildew pathogen, we wished to determine what specific cell wall changes are associated with disease resistance and why. The graduate student working on this project made mutations in the putative active site of PMR5, assuming it is a member of the SGNH/GDSL esterase superfamily (Anantharaman and Aravind, 2010, Biology Direct 5, 1). These mutants were inactive in planta suggesting that PMR5 is a functional enzyme and not a binding protein or chaperone. In addition, she determined that cell wall preparations from the pmr5 mutant exhibited a modest reduction (13%) in total acetyl groups. To pursue characterization further, the graduate student expressed the PMR5 protein in a heterologous E. coli system. She could purify PMR5 using a two step protocol based on tags added to the N and C terminus of the protein. She was able to show the PMR5 protein bound to pectins, including homogalacturonan, but not to other cell wall components (e.g., xyloglucans, arabinans). Based on these observations, a postdoctoral fellow is currently developing an enzyme assay for PMR5 based on the idea that it may be acetylating the homogalacturonic acid pectin fraction. Our initial experiments to localize PMR5 subcellularly suggested that it occurred in the endoplasmic reticulum. However, since the various pectins are believed to be synthesized in the Golgi apparatus, we felt it necessary to repeat our results using a native promoter expression system. Within the past year, we have demonstrated conclusively that PMR5 is localized to the endoplasmic reticulum, a location that sets it apart from most cell wall biogenesis and modification enzymes. The graduate student contributed to the characterization of two suppressor mutants, which were selected as restoring powdery

  6. Triticale powdery mildew: population characterization and wheat gene efficiency.

    Science.gov (United States)

    Bouguennec, Annaig; Trottet, Maxime; du Cheyron, Philippe; Lonnet, Philippe

    2014-01-01

    Powdery mildew has emerged on triticale in the early 2000s in many locations, probably due to a host range expansion of the wheat formae speciales, Blumeria graminis f.sp. tritici. Many triticale cultivars are highly susceptible to powdery mildew, mainly in seedling stage, revealing a probably narrow genetic basis for powdery mildew resistance genes (Pm). Moreover, as Blumeria graminis is an obligate biotrophic fungus, it is very time consuming and difficult to maintain powdery mildew isolates for a non-specialized laboratory and populations can evolve. In order to identify wheat Pm genes efficient against natural populations of powdery mildew, wheat differential hosts and triticale seedlings were inoculated below susceptible triticale crop naturally contaminated by mildew, in several locations and several years. Symptoms on seedlings were measured after approximately two weeks of incubation in favorable fungus growth conditions. According to these data, we classified the Pm genes presents in our wheat differential hosts set in 3 classes: Pm already overcame by triticale powdery mildew, Pm having variable effects and Pm still efficient against triticale mildew. Data on triticale seedlings allowed us to identify some few triticale cultivars resistant to Blumeria graminis in seedling stage. We will try to identify Pm genes present in those cultivars next year by testing them with the characterized isolates of powdery mildew from Gent University. Nevertheless, interspecific crossing of wheat, resistant to powdery mildew in seedling stage, and rye have been initiated to introduce potentially interesting genes for resistance in triticale.

  7. Using a limited mapping strategy to identify major QTLs for resistance to grapevine powdery mildew (Erysiphe necator) and their use in marker-assisted breeding.

    Science.gov (United States)

    Riaz, S; Tenscher, A C; Ramming, D W; Walker, M A

    2011-04-01

    A limited genetic mapping strategy based on simple sequence repeat (SSR) marker data was used with five grape populations segregating for powdery mildew (Erysiphe necator) resistance in an effort to develop genetic markers from multiple sources and enable the pyramiding of resistance loci. Three populations derived their resistance from Muscadinia rotundifolia 'Magnolia'. The first population (06708) had 97 progeny and was screened with 137 SSR markers from seven chromosomes (4, 7, 9, 12, 13, 15, and 18) that have been reported to be associated with powdery or downy mildew resistance. A genetic map was constructed using the pseudo-testcross strategy and QTL analysis was carried out. Only markers from chromosome 13 and 18 were mapped in the second (04327) and third (06712) populations, which had 47 and 80 progeny, respectively. Significant QTLs for powdery mildew resistance with overlapping genomic regions were identified for different tissue types (leaf, stem, rachis, and berry) on chromosome 18, which distinguishes the resistance in 'Magnolia' from that present in other accessions of M. rotundifolia and controlled by the Run1 gene on chromosome 12. The 'Magnolia' resistance locus was termed as Run2.1. Powdery mildew resistance was also mapped in a fourth population (08391), which had 255 progeny and resistance from M. rotundifolia 'Trayshed'. A locus accounting for 50% of the phenotypic variation mapped to chromosome 18 and was named Run2.2. This locus overlapped the region found in the 'Magnolia'-based populations, but the allele sizes of the flanking markers were different. 'Trayshed' and 'Magnolia' shared at least one allele for 68% of the tested markers, but alleles of the other 32% of the markers were not shared indicating that the two M. rotundifolia selections were very different. The last population, 08306 with 42 progeny, derived its resistance from a selection Vitis romanetii C166-043. Genetic mapping discovered a major powdery mildew resistance locus

  8. Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi.

    Science.gov (United States)

    Liyanage, K K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

    2017-02-09

    Powdery mildew is a fungal disease that infects a wide range of plants, including rubber trees, which results in a reduction of latex yields of up to 45%. The causal agent of powdery mildew of rubber was first described as Oidium heveae, but later morpho-molecular research suggested that in the past, O. heveae has been confused with Erysiphe quercicola. However, it is still under debate whether the causal agent should be classified as a species of the genus Erysiphe emend. or Golovinomyces and Podosphaera, respectively. Therefore, the aim of this study was to undertake the morpho-molecular characterization of powdery mildew species associated with rubber trees, thus resolving these taxonomic issues. Morphological observation under light and scanning electron microscopes (SEM) clearly identified two morphotypes of the rubber powdery mildew. With the support of morphological and phylogenetic data, one of the two morphotypes was identified as the asexual morph of E. quercicola, while the second morphotype is still insufficiently known and according to the morphological results obtained we assume that it might belong to the genus Golovinomyces. More collections and additional molecular data are required for final conclusions regarding the exact taxonomic position of the second morphotype of rubber powdery mildew and its relation to the name O. heveae. The haplotype analysis identified eight haplotype groups of E. quercicola indicating the high genetic diversity of the species.

  9. Interaction between powdery mildew and barley with ¤mlo5¤ mildew resistance

    DEFF Research Database (Denmark)

    Lyngkjær, M.F.; Østergård, Hanne

    1998-01-01

    Powdery mildew infection of barley with the mlo5 barley powdery mildew resistance gene was examined, using near-isogenic barley lines, with and without mlo5 resistance, and two near-isogenic powdery mildew isolates, HL3/5 and GE3 with high (virulent) or low (avirulent) penetration efficiency...

  10. rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew

    Institute of Scientific and Technical Information of China (English)

    Na WANG; Yajun MA; Cuiyun YANG; Guanghui DAI; Zhezhi WANG

    2008-01-01

    To determine the pathogens of cucumber downy mildew and cucumber powdery mildew by molecular marker,we amplified and sequenced the rDNA-ITS region of the pathogens of cucumber downy mildew and cucumber powdery mildew collected from the Shanghai region.The intra-/interspecific sequence difference was analyzed by rDNA-ITS sequence.The results show that the length of rDNA-ITS1 and rDNA-ITS2 of cucumber downy mildew's pathogen was 141 bp and 406 bp,respectively,with GC contents of 41.13% in ITS1 and 46.8% (Minhang and Jinshan District,sml and sm2) or 46.55% (Pudong District,sm3) in ITS2.The rDNA-ITS sequence was intraspecific conservation.The interspecific difference was related with their kin relationship.The pathogen of cucumber downy mildew was identified as Pseudoperonospora cubensis by molecular marker.The length of rDNA-ITS1 and rDNA-ITS2 of cucumber powdery mildew's pathogen was 136 bp and 89 bp,respectively,with GC contents being 59.56% and 66.29%,and rDNA-ITS sequence being highly conservative in this study that was the same as Sphaerotheca cucurbitae.But the sequence difference between the strains in the Shanghai region in this study with S.fuliginea was 4.5%,which was identified by morphology.It is suggested that the pathogen of cucumber powdery mildew should be further clarified and determined.

  11. Bacillus sp. BS061 Suppresses Gray Mold and Powdery Mildew through the Secretion of Different Bioactive Substances.

    Science.gov (United States)

    Kim, Young-Sook; Song, Ja-Gyeong; Lee, In-Kyoung; Yeo, Woon-Hyung; Yun, Bong-Sik

    2013-09-01

    A Bacillus sp. BS061 significantly reduced disease incidence of gray mold and powdery mildew. To identify the active principle, the culture filtrate was partitioned between butanol and water. The antifungal activity against B. cinerea was evident in the butanol-soluble portion, and active substances were identified as cyclic lipopeptides, iturin A series, by nuclear magnetic resonance spectrometry (NMR) and mass analysis. Interestingly, antifungal activity against powdery mildew was observed in the water-soluble portion, suggesting that cyclic lipopeptides have no responsibility to suppress powdery mildew. This finding reveals that biocontrol agents of Bacillus origin suppress gray mold and powdery mildew through the secretion of different bioactive substances.

  12. The effectivity of Tilletiopsis albescens in biocontrol of powdery mildew

    DEFF Research Database (Denmark)

    Knudsen, I.M.B.; Skou, J.P.

    1993-01-01

    Tilletiopsis albescens grows well on powdery mildew fungi inoculated on barley or cucumber leaves and causes collapse of the colonies. Application of ballistospores or cut mycelium was equally effective for biocontrol, and the effectiveness tended to increase exponentially with the concentration...... of germinating units (conidia and cut mycelium) applied. Seventy percent relative humidity or more is required for effective biocontrol. Two applications of T. albescens in the period from 3 days before to 3 days after inoculation with powdery mildew were more effective than one. Applications before inoculation...... or 7 days after inoculation with powdery mildew had little effect. T. albescens followed the powdery mildew as it was disseminated to uninoculated leaves, but this did not result in an effective biocontrol. The potential for using T. albescens for biocontrol of powdery mildews is discussed....

  13. LIFEGUARD proteins support plant colonization by biotrophic powdery mildew fungi.

    Science.gov (United States)

    Weis, Corina; Hückelhoven, Ralph; Eichmann, Ruth

    2013-09-01

    Pathogenic microbes manipulate eukaryotic cells during invasion and target plant proteins to achieve host susceptibility. BAX INHIBITOR-1 (BI-1) is an endoplasmic reticulum-resident cell death suppressor in plants and animals and is required for full susceptibility of barley to the barley powdery mildew fungus Blumeria graminis f.sp. hordei. LIFEGUARD (LFG) proteins resemble BI-1 proteins in terms of predicted membrane topology and cell-death-inhibiting function in metazoans, but display clear sequence-specific distinctions. This work shows that barley (Hordeum vulgare L.) and Arabidopsis thaliana genomes harbour five LFG genes, HvLFGa-HvLFGe and AtLFG1-AtLFG5, whose functions are largely uncharacterized. As observed for HvBI-1, single-cell overexpression of HvLFGa supports penetration success of B. graminis f.sp. hordei into barley epidermal cells, while transient-induced gene silencing restricts it. In penetrated barley epidermal cells, a green fluorescent protein-tagged HvLFGa protein accumulates at the site of fungal entry, around fungal haustoria and in endosomal or vacuolar membranes. The data further suggest a role of LFG proteins in plant-powdery mildew interactions in both monocot and dicot plants, because stable overexpression or knockdown of AtLFG1 or AtLFG2 also support or delay development of the powdery mildew fungus Erysiphe cruciferarum on the respective Arabidopsis mutants. Together, this work has identified new modulators of plant-powdery mildew interactions, and the data further support functional similarities between BI-1 and LFG proteins beyond cell death regulation.

  14. Spatial aggregation of pathotypes of barley powdery mildew

    DEFF Research Database (Denmark)

    O'Hara, R.B.; Brown, J.K.M.

    1997-01-01

    Aggregation in the distribution of pathotypes of Erysiphe graminis f.sp. hordei, the barley powdery mildew pathogen, was investigated in field plots of 'Golden Promise', 'Proctor' and 'Tyra'. 'Golden Promise' and 'Proctor' have no effective mildew resistance alleles, whereas 'Tyra' has Mla1, which...

  15. Histo-chemical and biochemical analysis reveals association of er1 mediated powdery mildew resistance and redox balance in pea.

    Science.gov (United States)

    Mohapatra, Chinmayee; Chand, Ramesh; Navathe, Sudhir; Sharma, Sandeep

    2016-09-01

    Powdery mildew caused by Erysiphe pisi is one of the important diseases responsible for heavy yield losses in pea crop worldwide. The most effective method of controlling the disease is the use of resistant varieties. The resistance to powdery mildew in pea is recessive and governed by a single gene er1. The objective of present study is to investigate if er1 mediated powdery mildew resistance is associated with changes in the redox status of the pea plant. 16 pea genotypes were screened for powdery mildew resistance in field condition for two years and, also, analyzed for the presence/absence of er1 gene. Histochemical analysis with DAB and NBT staining indicates accumulation of reactive oxygen species (ROS) in surrounding area of powdery mildew infection which was higher in susceptible genotypes as compared to resistant genotypes. A biochemical study revealed that the activity of superoxide dismutase (SOD) and catalase, enzymes involved in scavenging ROS, was increased in, both, resistant and susceptible genotypes after powdery mildew infection. However, both enzymes level was always higher in resistant than susceptible genotypes throughout time course of infection. Moreover, irrespective of any treatment, the total phenol (TP) and malondialdehyde (MDA) content was significantly high and low in resistant genotypes, respectively. The powdery mildew infection elevated the MDA content but decreased the total phenol in pea genotypes. Statistical analysis showed a strong positive correlation between AUDPC and MDA; however, a negative correlation was observed between AUDPC and SOD, CAT and TP. Heritability of antioxidant was also high. The study identified few novel genotypes resistant to powdery mildew infection that carried the er1 gene and provided further clue that er1 mediated defense response utilizes antioxidant machinery to confer powdery mildew resistance in pea.

  16. IDENTIFICATION OF RAPD MARKER LINKED TO POWDERY MILDEW RESISTANCE GENE Pm 12 IN WHEAT

    Institute of Scientific and Technical Information of China (English)

    GU Feng; ZHANG Qing-li; GUO Xiao-chun; LI Tao; WANG Hong-gang

    2004-01-01

    Powdery mildew is one of the most serious diseases of wheat in China. In this paper,bulked segregant analysis (BSA) was used to search for randomly amplified polymorphic DNA (RAPD) markers linked to the Pm12 gene,which confers resistance to the powdery mildew in wheat. 200 decamer primers were screened and one RAPD marker (S1071900) was identified to be linked to Pm 12 in coupling phase, and their genetic distance is 11.98 ±4.00cM. This marker can be used for marker - assisted selection in wheat breeding for the identification or pyramiding of Pm12 with other resistance genes.Key Words: Wheat, RAPD, Powdery mildew, resistance genes.

  17. Interaction of barley powdery mildew effector candidate CSEP0055 with the defence protein PR17c

    DEFF Research Database (Denmark)

    Zhang, Wen-Jing; Pedersen, Carsten; Kwaaitaal, Mark Adrianus Cornelis J

    2012-01-01

    A large number of effector candidates have been identified recently in powdery mildew fungi. However, their roles and how they perform their functions remain unresolved. In this study, we made use of host-induced gene silencing and confirmed that the secreted barley powdery mildew effector...... candidate, CSEP0055, contributes to the aggressiveness of the fungus. This result suggests that CSEP0055 is involved in the suppression of plant defence. A yeast two-hybrid screen indicated that CSEP0055 interacts with members of the barley pathogenesis-related protein families, PR1 and PR17. Interaction...... with PR17c was confirmed by bimolecular fluorescence complementation analyses. Down-regulation and over-expression of PR17c in epidermal cells of barley confirmed that this protein is important for penetration resistance against the powdery mildew fungus. In line with this, PR17c was found...

  18. Sequence and phylogenetic analyses of novel totivirus-like double-stranded RNAs from field-collected powdery mildew fungi.

    Science.gov (United States)

    Kondo, Hideki; Hisano, Sakae; Chiba, Sotaro; Maruyama, Kazuyuki; Andika, Ida Bagus; Toyoda, Kazuhiro; Fujimori, Fumihiro; Suzuki, Nobuhiro

    2016-02-02

    The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field-collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (powdery mildew fungus populations infecting red clover plants in the field.

  19. QTL Mapping for Adult Plant Resistance to Powdery Mildew in Italian Wheat cv. Strampelli

    Institute of Scientific and Technical Information of China (English)

    Asad Muhammad Azeem; BAI Bin; LAN Cai-xia; YAN Jun; XIA Xian-chun; ZHANG Yong; HE Zhong-hu

    2013-01-01

    The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci (QTLs) for resistance to powdery mildew in a population of 249 F2:3 lines from Strampelli/Huixianhong. Adult plant powdery mildew tests were conducted over 2 yr in Beijing and 1 yr in Anyang and simple sequence repeat (SSR) markers were used for genotyping. QTLs Qpm.caas-3BS, Qpm.caas-5BL.1, and Qpm.caas-7DS were consistent across environments whereas, Qpm.caas-2BS.1 found in two environments, explained 0.4-1.6, 5.5-6.9, 27.1-34.5, and 1.0-3.5%of the phenotypic variation respectively. Qpm.caas-7DS corresponded to the genomic location of Pm38/Lr34/Yr18. Qpm.caas-4BL was identified in Anyang 2010 and Beijing 2011, accounting for 1.9-3.5%of phenotypic variation. Qpm.caas-2BS.1 and Qpm.caas-5BL.1 contributed by Strampelli and Qpm.caas-3BS by Huixianhong, seem to be new QTL for powdery mildew resistance. Qpm.caas-4BL, Qpm.caas-5BL.3, and Qpm.caas-7DS contributed by Strampelli appeared to be in the same genomic regions as those mapped previously for stripe rust resistance in the same population, indicating that these loci conferred resistance to both stripe rust and powdery mildew. Strampelli could be a valuable genetic resource for improving durable resistance to both powdery mildew and stripe rust in wheat.

  20. Strategies for RUN1 deployment using RUN2 and REN2 to manage grapevine powdery mildew informed by studies of race-specificity

    Science.gov (United States)

    The TIR-NB-LRR gene, Resistance to Uncinula necator 1 (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic Vitis vinifera cultivars. However, powdery mildew cleistothecia ha...

  1. Fine physical and genetic mapping of powdery mildew resistance gene MlIW172 originating from wild emmer(Triticum dicoccoides)

    Science.gov (United States)

    Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most important wheat diseases in the world. In this study, a single dominant powdery mildew resistance gene MlIW172 was identified in the IW172 wild emmer accession and mapped to the distal region of chromosome arm 7AL (bin7A...

  2. Powdery Mildew Resistance in 268 Entries of Hordeum vulgare

    DEFF Research Database (Denmark)

    Jiang, W.M.; Jørgensen, Jørgen Helms; Torp, J

    1984-01-01

    A collection of 24 'Spontaneum' barley [H. vulgare ssp. spontaneum] entries and one comprising 244 Ethiopian barleys [H. vulgare ssp. vulgare] were tested for resistance to 4 powdery mildew [used by Erysiphe graminis f. sp. hordei] cultures that carried genes for virulence corresponding to most...... of the known powdery mildew resistance genes. The infection types and spectra of resistance were compared to those of 31 test lines with 35 known resistance genes to find possible new resistance genes and to reveal known resistance genes. The collections may possess some new and some known resistance genes...

  3. The relationship between powdery mildew (Sphaerotheca fuliginea) resistance and leaf chlorosis sensitivity in cucumber (Cucumis sativus) studied in single seed descent lines

    NARCIS (Netherlands)

    Zijlstra, S.; Jansen, R.C.; Groot, S.P.C.

    1995-01-01

    The genetic relation between powdery mildew resistance and sensitivity for leaf chlorosis of glasshouse cucumber was investigated. The powdery mildew resistant, leaf chlorosis sensitive hybrid variety 'Profito' was crossed with the powdery mildew susceptible, non chlorosis sensitive hybrid variety '

  4. Evidence for cucurbit powdery mildew pathogen races based on watermelon differentials

    Science.gov (United States)

    Powdery mildew (PM) caused by Podosphaera xanthii occurs in open fields and greenhouses and can severely limit cucurbit production. Presently seven races of P. xanthii have been identified using melon (Cucumis melo) differentials. Physiological races of this pathogen have not been classified for ot...

  5. Transcriptional, microscopic and macroscopic investigations into monogenic and polygenic interactions of tomato and powdery mildew

    NARCIS (Netherlands)

    Li Chengwei,

    2005-01-01

    Powdery mildew ( Oidium neolycopersici) is a worldwide obligate fungal disease of tomato ( Solanum lycopersicum ). Six monogenic Ol genes and three major QTLs were identified and mapped on tomato genome. In this thesis, the mechanisms of both compatible and incompatible interactions of tomato and O.

  6. New Sources of Resistance to Cucurbit Powdery Mildew in Melon

    Science.gov (United States)

    Many physiological races of the cucurbit powdery mildew pathogen (CPM) Podosphaera xanthii (Castagne) Braun & Shishkoff have been reported on melon (Cucumis melo L.). Melon accession PI 313970 is the only reported source of host plant resistance to race S, which first appeared in Imperial Valley, CA...

  7. Hop powdery mildew control through alteration of spring pruning practices

    Science.gov (United States)

    Since 1997, Podosphaera macularis, the causal agent of hop powdery mildew, has become a recurrent threat to hops in the Pacific Northwest because of the potential to reduce cone yield and quality. Disease management practices often involve preventative fungicide applications, but alternative approac...

  8. Structure and evolution of barley powdery mildew effector candidates

    DEFF Research Database (Denmark)

    Pedersen, Carsten; Themaat, Emiel Ver Loren van; McGuffin, Liam J.;

    2012-01-01

    Protein effectors of pathogenicity are instrumental in modulating host immunity and disease resistance. The powdery mildew pathogen of grasses Blumeria graminis causes one of the most important diseases of cereal crops. B. graminis is an obligate biotrophic pathogen and as such has an absolute...

  9. Identification of novel powdery mildew resistance sources in wheat

    Science.gov (United States)

    Powdery mildew is a globally dominating disease of wheat with a high occurrence frequency, and genetic resistance plays an important role in managing this devastating disease. The objectives of this study were to evaluate leaf rust resistance and the underlying genes of breeding lines in the USA, a...

  10. Response of yellow flowering magnolia varieties to powdery mildew, 2015

    Science.gov (United States)

    Yellow flowering varieties of Magnolia spp. hybrids were planted in April 2008 in a field plot with Waynesboro loam soil at the Otis L. Floyd Nursery Research Center in McMinnville, TN. Severity of powdery mildew was determined on 14 Jul, 21 Aug and 15 Oct using a scale of 0-100% foliage affected. ...

  11. Structure and evolution of barley powdery mildew effector candidates

    DEFF Research Database (Denmark)

    Pedersen, Carsten; Themaat, Emiel Ver Loren van; McGuffin, Liam J.;

    2012-01-01

    Protein effectors of pathogenicity are instrumental in modulating host immunity and disease resistance. The powdery mildew pathogen of grasses Blumeria graminis causes one of the most important diseases of cereal crops. B. graminis is an obligate biotrophic pathogen and as such has an absolute...... requirement to suppress or avoid host immunity if it is to survive and cause disease....

  12. Importance of prumycin produced by Bacillus amyloliquefaciens SD-32 in biocontrol against cucumber powdery mildew disease.

    Science.gov (United States)

    Tanaka, Keijitsu; Fukuda, Mutsumi; Amaki, Yusuke; Sakaguchi, Takatoshi; Inai, Koji; Ishihara, Atsushi; Nakajima, Hiromitsu

    2017-05-30

    Powdery mildew disease of cucurbits is caused mainly by Podosphaera fusca, which is one of the most important limiting factors in cucurbit production worldwide. Previously we reported that Bacillus amyloliquefaciens biocontrol strain SD-32 produces C17 bacillomycin D and [Ile]surfactin, and that these metabolites play important roles in SD-32's biocontrol over cucumber gray mold disease. Our further investigation demonstrated that the culture broth and its supernatant suppressed cucumber powdery mildew disease in greenhouse experiments. However, the active principle(s) remained unknown. The active compound was isolated from the culture supernatant after anti-powdery mildew disease activity-guided purification and identified as prumycin. Prumycin significantly suppressed the disease, whereas bacillomycin D and [Ile]surfactin did not. Prumycin did not induce the expression of plant defense genes (PR1a and VSP1), suggesting that it does not act via plant defense response. Light microscopic observations of prumycin-treated cucumber cotyledon suggested that prumycin inhibits the conidial germination of P. fusca. This study demonstrates that prumycin is a major factor in SD-32's suppression of cucumber powdery mildew disease. Our findings shed light for the first time on prumycin's role in biocontrol by Bacillus against this disease. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Mildew-omics: How global analyses aid the understanding of life and evolution of powdery mildews

    Directory of Open Access Journals (Sweden)

    Laurence Veronique Bindschedler

    2016-02-01

    Full Text Available The common powdery mildew plant diseases are caused by ascomycete fungi of the order Erysiphales. Their characteristic life style as obligate biotrophs renders functional analyses in these species challenging, mainly because of experimental constraints to genetic manipulation. Global large-scale (-omics approaches are thus particularly valuable and insightful for the characterisation of the life and evolution of powdery mildews. Here we review the knowledge obtained so far from genomic, transcriptomic and proteomic studies in these fungi. We consider current limitations and challenges regarding these surveys and provide an outlook on desired future investigations on the basis of the various –omics technologies.

  14. Host cell entry of powdery mildew is correlated with endosomal transport of antagonistically acting VvPEN1 and VvMLO to the papilla.

    Science.gov (United States)

    Feechan, A; Jermakow, A M; Ivancevic, A; Godfrey, D; Pak, H; Panstruga, R; Dry, I B

    2013-10-01

    Challenge by a nonadapted powdery mildew fungal pathogen leads to the formation of a local cell-wall apposition (papilla) beneath the point of attempted penetration. Several plasma membrane (PM) proteins with opposing roles in powdery mildew infection, including Arabidopsis thaliana PENETRATION1 (PEN1) and barley (Hordeum vulgare) MILDEW RESISTANCE LOCUS O (MLO), are localized to the site of powdery mildew attack. PEN1 contributes to penetration resistance to nonadapted powdery mildews, whereas MLO is a susceptibility factor required by adapted powdery mildew pathogens for host cell entry. Our previous studies have demonstrated that the vesicle and endosomal trafficking inhibitors, brefeldin A and wortmannin, have opposite effects on the penetration rates of adapted and nonadapted powdery mildews on grapevine. These findings prompted us to study the pathogen-induced intracellular trafficking of grapevine variants of MLO and PEN1. We first identified grapevine (Vitis vinifera) VvPEN1 and VvMLO orthologs that rescue Arabidopsis Atpen1 and Atmlo2 mlo6 mlo12 null mutants, respectively. By using endomembrane trafficking inhibitors in combination with fluorescence microscopy, we demonstrate that VvMLO3/VvMLO4 and VvPEN1 are co-trafficked together from the PM to the site of powdery mildew challenge. This focal accumulation of VvMLO3/VvMLO4 and VvPEN1 to the site of attack seems to be required for their opposing functions during powdery mildew attack, because their subcellular localization is correlated with the outcome of attempted powdery mildew penetration.

  15. Whole-Genome Resequencing of a Cucumber Chromosome Segment Substitution Line and Its Recurrent Parent to Identify Candidate Genes Governing Powdery Mildew Resistance

    Science.gov (United States)

    Yu, Ting; Xu, Xuewen; Yan, Yali; Qi, Xiaohua; Chen, Xuehao

    2016-01-01

    Cucumber is an economically important vegetable crop worldwide. Powdery mildew (PM) is one of the most severe diseases that can affect cucumber crops. There have been several research efforts to isolate PM resistance genes for breeding PM-resistant cucumber. In the present study, we used a chromosome segment substitution line, SSL508-28, which carried PM resistance genes from the donor parent, JIN5-508, through twelve generations of backcrossing with a PM-susceptible inbred line, D8. We performed whole-genome resequencing of SSL508-28 and D8 to identify single nucleotide polymorphisms (SNPs), and insertions and deletions (indels). When compared against the reference genome of the inbred cucumber line 9930, a total of 468,616 SNPs and 67,259 indels were identified in SSL508-28, and 537,352 SNPs and 91,698 indels were identified in D8. Of these, 3,014 non-synonymous SNPs and 226 frameshift indels in SSL508-28, and 3,104 non-synonymous SNPs and 251 frameshift indels in D8, were identified. Bioinformatics analysis of these variations revealed a total of 15,682 SNPs and 6,262 indels between SSL508-28 and D8, among which 120 non-synonymous SNPs and 30 frameshift indels in 94 genes were detected between SSL508-28 and D8. Finally, out of these 94 genes, five resistance genes with nucleotide-binding sites and leucine-rich repeat domains were selected for qRT-PCR analysis. This revealed an upregulation of two transcripts, Csa2M435460.1 and Csa5M579560.1, in SSL508-28. Furthermore, the results of qRT-PCR analysis of these two genes in ten PM resistant and ten PM susceptible cucumber lines showed that when exposed to PM, Csa2M435460.1 and Csa5M579560.1 exhibited a higher expression level of resistant lines than susceptible lines. This indicates that Csa2M435460.1 and Csa5M579560.1 are candidate genes for PM resistance in cucumber. In addition, the non-synonymous SNPs in Csa2M435460.1 and Csa5M579560.1, identified in SSL508-28 and D8, might be the key to high PM-resistance in

  16. Rationalization of pesticide treatments against powdery mildew of grape.

    Science.gov (United States)

    Spera, G; La Torre, A; Gianferro, M; Bugliosi, R

    2007-01-01

    The powdery mildew represents one of the diseases which affect the grape, it is diffused in all agricultural regions with variable intensity and epidemic course in operation of many microclimatic factors. The powdery mildew of grape is caused from Uncinala necator (Schw.) Burr. (nowadays named Erysiphe necator Schwein.); it is controlled with systemic therapy and contact chemicaL products. In some vineyards located in Latium (central Italy), different field trials have been carried out purposely to rationalize the treatments against E. necator. We have studied the powdery mildew infections through monitoring a set of environmental parameters, the evaluation of cultivar sensibility, the agricultural production method and the area characteristics. We have analysed the following environmental parameters monitoring every 15 minutes: precipitation, soil temperature, solar radiation, wind direction, wind speed, atmospheric relative humidity, atmospheric temperature, leaf wetness, soil humidity to cm 20 and soil humidity to cm 40. Besides, we have used Artificial Intelligence analysis techniques to try to forecast U. necator infections. Guideline EPPO/OEPP PP 1/4 (4) has been used. The trials were conducted in conventional and organic farms. In 2 conventional farms and in organic farm we have considered 1 untreated control thesis, in order to follow the course of infection, 1 standard farm reference thesis (standard), where the treatments were carried out according to the usual farm procedures and 1 thesis where the treatments were carried out according to examining the environmental data. In another conventional vineyard, we have considered only 1 untreated control thesis and 1 standard farm reference thesis (standard) to study disease trend. The achieved results have underlined the possibility (through the knowledge of data pedoclimatic and cultural) to position the treatments against the powdery mildew so that to reduce their number. The lower number of treatments that

  17. Cytological and molecular analysis of nonhost resistance in rice to wheat powdery mildew and leaf rust pathogens.

    Science.gov (United States)

    Cheng, Yulin; Yao, Juanni; Zhang, Hongchang; Huang, Lili; Kang, Zhensheng

    2015-07-01

    Cereal powdery mildews caused by Blumeria graminis and cereal rusts caused by Puccinia spp. are constant disease threats that limit the production of almost all important cereal crops. Rice is an intensively grown agricultural cereal that is atypical because of its immunity to all powdery mildew and rust fungi. We analyzed the nonhost interactions between rice and the wheat powdery mildew fungus B. graminis f. sp. tritici (Bgt) and the wheat leaf rust fungus Puccinia triticina (Ptr) to identify the basis of nonhost resistance (NHR) in rice against cereal powdery mildew and rust fungi at cytological and molecular levels. No visible symptoms were observed on rice leaves inoculated with Bgt or Ptr. Microscopic observations showed that both pathogens exhibited aberrant differentiation and significantly reduced penetration frequencies on rice compared to wheat. The development of Bgt and Ptr was also completely arrested at early infection stages in cases of successful penetration into rice leaves. Attempted infection of rice by Bgt and Ptr induced similar defense responses, including callose deposition, accumulation of reactive oxygen species, and hypersensitive response in rice epidermal and mesophyll cells, respectively. Furthermore, a set of defense-related genes were upregulated in rice against Bgt and Ptr infection. Rice is an excellent monocot model for genetic and molecular studies. Therefore, our results demonstrate that rice is a useful model to study the mechanisms of NHR to cereal powdery mildew and rust fungi, which provides useful information for the development of novel and durable strategies to control these important pathogens.

  18. QTL mapping of powdery mildew resistance in WI 2757 cucumber (Cucumis sativus L)

    Science.gov (United States)

    Powdery mildew is a serious fungal disease of cucumber and other cucurbot crops in the US and many other parts of the world. Resistant cultivars have been deployed in production for a long time, but the genetic mechanisms of powdery mildew resistance in cucumber are not well understood. In a three-y...

  19. Evaluation and Quantitative trait loci mapping of resistance to powdery mildew in lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is the major leafy vegetable that is susceptible to powdery mildew disease under greenhouse and field conditions. We mapped quantitative trait loci (QTLs) for resistance to powdery mildew under greenhouse conditions in an interspecific population derived from a cross betw...

  20. Powdery mildew caused by Podosphaera macularis on hop (Humulus lupulus) in North Carolina

    Science.gov (United States)

    In June 2015, a grower in western North Carolina detected powdery mildew in a small hop yard. Characteristic colonies of the pathogen where observed on cultivars Cashmere, Cascade, and Chinook. Leaves with powdery mildew were collected from cultivar Cashmere for confirmation of the pathogen identi...

  1. Characterization of resistance to powdery mildew in the Hop cultivars Newport and Comet

    Science.gov (United States)

    Hop powdery mildew, caused by Podosphaera macularis, is an important disease in the Northwestern U.S. Outbreaks of powdery mildew on cultivars previously resistant to the disease have been reported increasingly with the emergence of virulent pathogen strains capable of overcoming a commonly deployed...

  2. Role of MLO genes in susceptibility to powdery mildew in apple and grapevine

    NARCIS (Netherlands)

    Pessina, Stefano

    2016-01-01

    Powdery mildew (PM) is a major fungal disease that threatens thousands of plant species. PM is caused by Podosphaera leucotricha in apple and Erysiphe necator in grapevine. Powdery mildew is controlled by frequent applications of fungicides, having negative effects on the environment, and leading to

  3. Powdery mildew fungal effector candidates share N-terminal Y/F/WxC-motif

    Directory of Open Access Journals (Sweden)

    Emmersen Jeppe

    2010-05-01

    Full Text Available Abstract Background Powdery mildew and rust fungi are widespread, serious pathogens that depend on developing haustoria in the living plant cells. Haustoria are separated from the host cytoplasm by a plant cell-derived extrahaustorial membrane. They secrete effector proteins, some of which are subsequently transferred across this membrane to the plant cell to suppress defense. Results In a cDNA library from barley epidermis containing powdery mildew haustoria, two-thirds of the sequenced ESTs were fungal and represented ~3,000 genes. Many of the most highly expressed genes encoded small proteins with N-terminal signal peptides. While these proteins are novel and poorly related, they do share a three-amino acid motif, which we named "Y/F/WxC", in the N-terminal of the mature proteins. The first amino acid of this motif is aromatic: tyrosine, phenylalanine or tryptophan, and the last is always cysteine. In total, we identified 107 such proteins, for which the ESTs represent 19% of the fungal clones in our library, suggesting fundamental roles in haustoria function. While overall sequence similarity between the powdery mildew Y/F/WxC-proteins is low, they do have a highly similar exon-intron structure, suggesting they have a common origin. Interestingly, searches of public fungal genome and EST databases revealed that haustoria-producing rust fungi also encode large numbers of novel, short proteins with signal peptides and the Y/F/WxC-motif. No significant numbers of such proteins were identified from genome and EST sequences from either fungi which do not produce haustoria or from haustoria-producing Oomycetes. Conclusion In total, we identified 107, 178 and 57 such Y/F/WxC-proteins from the barley powdery mildew, the wheat stem rust and the wheat leaf rust fungi, respectively. All together, our findings suggest the Y/F/WxC-proteins to be a new class of effectors from haustoria-producing pathogenic fungi.

  4. Preliminary research on the identification system for anthracnose and powdery mildew of sandalwood leaf based on image processing.

    Science.gov (United States)

    Wu, Chunyan; Wang, Xuefeng

    2017-01-01

    This paper presents a survey on a system that uses digital image processing techniques to identify anthracnose and powdery mildew diseases of sandalwood from digital images. Our main objective is researching the most suitable identification technology for the anthracnose and powdery mildew diseases of the sandalwood leaf, which provides algorithmic support for the real-time machine judgment of the health status and disease level of sandalwood. We conducted real-time monitoring of Hainan sandalwood leaves with varying severity levels of anthracnose and powdery mildew beginning in March 2014. We used image segmentation, feature extraction and digital image classification and recognition technology to carry out a comparative experimental study for the image analysis of powdery mildew, anthracnose disease and healthy leaves in the field. Performing the actual test for a large number of diseased leaves pointed to three conclusions: (1) Distinguishing effects of BP (Back Propagation) neural network method, in all kinds of classical methods, for sandalwood leaf anthracnose and powdery mildew disease are relatively good; the size of the lesion areas were closest to the actual. (2) The differences between two diseases can be shown well by the shape feature, color feature and texture feature of the disease image. (3) Identifying and diagnosing the diseased leaves have ideal results by SVM, which is based on radial basis kernel function. The identification rate of the anthracnose and healthy leaves was 92% respectively, and that of powdery mildew was 84%. Disease identification technology lays the foundation for remote monitoring disease diagnosis, preparing for remote transmission of the disease images, which is a very good guide and reference for further research of the disease identification and diagnosis system in sandalwood and other species of trees.

  5. Reprint of "Sequence and phylogenetic analyses of novel totivirus-like double-stranded RNAs from field-collected powdery mildew fungi".

    Science.gov (United States)

    Kondo, Hideki; Hisano, Sakae; Chiba, Sotaro; Maruyama, Kazuyuki; Andika, Ida Bagus; Toyoda, Kazuhiro; Fujimori, Fumihiro; Suzuki, Nobuhiro

    2016-07-02

    The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field-collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (powdery mildew fungus populations infecting red clover plants in the field.

  6. Identification of Powdery Mildew Responsive Genes in Hevea brasiliensis through mRNA Differential Display.

    Science.gov (United States)

    Li, Xiang; Bi, Zhenghong; Di, Rong; Liang, Peng; He, Qiguang; Liu, Wenbo; Miao, Weiguo; Zheng, Fucong

    2016-01-29

    Powdery mildew is an important disease of rubber trees caused by Oidium heveae B. A. Steinmann. As far as we know, none of the resistance genes related to powdery mildew have been isolated from the rubber tree. There is little information available at the molecular level regarding how a rubber tree develops defense mechanisms against this pathogen. We have studied rubber tree mRNA transcripts from the resistant RRIC52 cultivar by differential display analysis. Leaves inoculated with the spores of O. heveae were collected from 0 to 120 hpi in order to identify pathogen-regulated genes at different infection stages. We identified 78 rubber tree genes that were differentially expressed during the plant-pathogen interaction. BLAST analysis for these 78 ESTs classified them into seven functional groups: cell wall and membrane pathways, transcription factor and regulatory proteins, transporters, signal transduction, phytoalexin biosynthesis, other metabolism functions, and unknown functions. The gene expression for eight of these genes was validated by qRT-PCR in both RRIC52 and the partially susceptible Reyan 7-33-97 cultivars, revealing the similar or differential changes of gene expressions between these two cultivars. This study has improved our overall understanding of the molecular mechanisms of rubber tree resistance to powdery mildew.

  7. PHOTOSYNTHETIC PIGMENTS IN HEVEA CLONES UNDER POWDERY MILDEW ATTACK

    Directory of Open Access Journals (Sweden)

    Gisely Cristina Gonzalez

    2013-08-01

    Full Text Available http://dx.doi.org/10.5902/1980509810561The rubber tree [Hevea brasiliensis (Willd. ex Adr. Of Juss. Muell. Arg.] can be affected by the occurrence of the fungus Oidium heveae, which causes one of the most important diseases of rubber trees, powdery mildew. This work studied meet changes in photosynthetic pigments, an indicator of oxidative stress, in seedlings of three Hevea brasiliensis clones, RRIM 600, GT1 and PR255, under infection in Oidium heveae. The experiment was conducted in an open environment under natural photoperiod conditions and at the beginning of the trial, the rubber plants would be inoculated were sprayed with an aqueous suspension containing O. heveae at a concentration of 16 x 104 conidia mL-1. On the day of inoculation and after 48, 96, 144 and 192 h leaf samples were collected for the determination of photosynthetic pigments. Degradation in photosynthetic pigments in the period of infection was observed in rubber tree clones studied; thus, there is oxidative stress in clones of rubber trees. No promising genetic material for genetic improvement work stress tolerance by Oidium heveae was identified.

  8. Biocontrol agent Bacillus amyloliquefaciens LJ02 induces systemic resistance against cucurbits powdery mildew.

    Science.gov (United States)

    Li, Yunlong; Gu, Yilin; Li, Juan; Xu, Mingzhu; Wei, Qing; Wang, Yuanhong

    2015-01-01

    Powdery mildew is a fungal disease found in a wide range of plants and can significantly reduce crop yields. Bacterial strain LJ02 is a biocontrol agent (BCA) isolated from a greenhouse in Tianjin, China. In combination of morphological, physiological, biochemical and phylogenetic analyses, strain LJ02 was classified as a new member of Bacillus amyloliquefaciens. Greenhouse trials showed that LJ02 fermentation broth (LJ02FB) can effectively diminish the occurrence of cucurbits powdery mildew. When treated with LJ02FB, cucumber seedlings produced significantly elevated production of superoxide dismutase, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase as compared to that of the control. We further confirmed that the production of free salicylic acid (SA) and expression of one pathogenesis-related (PR) gene PR-1 in cucumber leaves were markedly elevated after treating with LJ02FB, suggesting that SA-mediated defense response was stimulated. Moreover, LJ02FB-treated cucumber leaves could secrete resistance-related substances into rhizosphere that inhibit the germination of fungi spores and the growth of pathogens. Finally, we separated bacterium and its fermented substances to test their respective effects and found that both components have SA-inducing activity and bacterium plays major roles. Altogether, we identified a BCA against powdery mildew and its mode of action by inducing systemic resistance such as SA signaling pathway.

  9. Powdery Mildew Control and Yield Response of Inodorus Melon

    Directory of Open Access Journals (Sweden)

    Ippolito Camele

    Full Text Available The research was carried out on melon (Cucumis melo L. var. inodorus Naud. in 2006 and 2007 at “Pantanello” Experimental Farm (40° 24’N; 16° 48’E; 10 m a.s.l.; Metaponto, southern Italy to evaluate the efficacy of a low environmental impact control strategy against powdery mildew of cucurbits. Winter melon was treated with a new anti-oidium formulation, called Stifénia, obtained from fenugreek seeds and stimulating the plant self-defence. The adopted experimental design included two control strategies (1. biological, using Stifénia and 2. conventional, using penconazole, myclobutanil and sulphur and an untreated control (treated with water alone applied to two cultivars of inodorus melon (cv ‘Amarillo’ and HF1 ‘Cocorito’, the latter a genotype resistant to powdery mildew. Stifénia applications were not effective against the disease; in fact, there were no differences in percentage of attacked plant surface between treated plots and untreated ones. The melon marketable yield was significantly higher with the conventional strategy respect to Stifénia and control. Repeated applications of Stifénia resulted in a significant decrease of marketable yield even in comparison with the untreated control. The cultivars significantly affected powdery mildew development, since the resistant one (‘Cocorito’ was attacked later and damaged always lower than the non-resistant genotype (‘Amarillo’. Laboratory analyses carried out on infected leaves always confirmed that Golovinomyces cichoracearum D.C. was responsible of the disease.

  10. Morphological and phylogenetic comparisons amongst powdery mildews on Catalpa in the UK.

    Science.gov (United States)

    Cook, Roger T A; Henricot, Béatrice; Henrici, Alick; Beales, Paul

    2006-06-01

    Three species of powdery mildew, Erysiphe elevata, E. catalpae, and Neoerysiphe galeopsidis were identified on Catalpa species in England in 2004. A new disease record, N. galeopsidis was the first Catalpa mildew to appear (in June), but it was later out-competed by E. elevata that caused the most serious damage. Both mildews also attacked C. speciosa, C. xerubescens and a new host, xChitalpa tashkentensis, a Chilopsis xCatalpa hybrid. No powdery mildew was detected on C. bungei, C. ovata, or C. fargesii. Identifications of the pathogens using morphological data were fully supported by DNA analysis yielding characteristic rDNA ITS sequences. The sequences placed E. catalpae within the E. aquilegiae clade. The sequences for E. elevata from southern England and France closely matched those from Hungary and North America, confirming the recent spread of this pathogen from the USA. It eventually overran N. galeopsidis and its sudden appearance in the UK could be due to greater aggressiveness and to the production of more ascomata especially during autumns with delayed leaf fall as in 2001. A further species, Oidium hiratae (i.e. Podosphaera sp.), though described from a 1978 UK collection on C. bignonioides, was not detected in the field.

  11. Indirect effect of a transgenic wheat on aphids through enhanced powdery mildew resistance.

    Directory of Open Access Journals (Sweden)

    Simone von Burg

    Full Text Available In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew became more favourable for another pest (aphids.

  12. Indirect effect of a transgenic wheat on aphids through enhanced powdery mildew resistance.

    Science.gov (United States)

    von Burg, Simone; Álvarez-Alfageme, Fernando; Romeis, Jörg

    2012-01-01

    In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici) and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM) mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew) became more favourable for another pest (aphids).

  13. Fine mapping of a dominantly inherited powdery mildew resistance major-effect QTL, Pm1.1, in cucumber identifies a 41.1 kb region containing two tandemly arrayed cysteine-rich receptor-like protein kinase genes

    Science.gov (United States)

    Powdery mildew (PM) is a severe fungal disease in cucumber, but the molecular genetic mechanisms of PM resistance in cucumber are still poorly understood. In this study, through marker-assisted backcrossing with an elite susceptible inbred line D8, we developed a single segment substitution line SSS...

  14. Map - vs. homology - based cloning for the recessive gene ol-2 conferring resistance to tomato powdery mildew

    NARCIS (Netherlands)

    Pavan, S.N.C.; Zheng, Z.; Borisova, M.; Berg, van den P.M.M.M.; Lotti, C.; Giovanni, de C.; Lindhout, P.; Jong, de J.H.; Ricciardi, L.; Visser, R.G.F.; Bai, Y.

    2008-01-01

    The recessive gene ol-2 confers papilla-associated and race-non-specific resistance to tomato powdery mildew caused by Oidium neolycopersici. In order to facilitate marker assisted selection (MAS) in practical breeding programmes, we identified two simple sequence repeat (SSR) markers and one

  15. Field assessment of partial resistance to powdery mildew in spring barley

    DEFF Research Database (Denmark)

    Nørgaard Knudsen, J. Chr.; Dalsgaard, H. H.; Jørgensen, Jørgen Helms

    1986-01-01

    Partial resistance to powdery mildew in spring barley was evaluated in three plot types: large isolation plots, in 1.4 m2 plots in chessboard design with guard plots of spring wheat and in single rows. Percentage leaf area covered by powdery mildew was scored four to six times during the season....... The relationship between single scores of amount of powdery mildew on the upper four leaves and the area under the disease progress curve was high in all plot designs during the first two to three weeks after heading, allowing selection for the trait by one or two scorings. Differential ranking of varieties...

  16. Detection of pre-symptomatic rose powdery-mildew and gray-mold diseases based on thermal vision

    Science.gov (United States)

    Jafari, M.; Minaei, S.; Safaie, N.

    2017-09-01

    Roses are the most important plants in ornamental horticulture. Roses are susceptible to a number of phytopathogenic diseases. Among the most serious diseases of rose, powdery mildew (Podosphaera pannosa var. rosae) and gray mold (Botrytis cinerea) are widespread which require considerable attention. In this study, the potential of implementing thermal imaging to detect the pre-symptomatic appearance of these fungal diseases was investigated. Effects of powdery mildew and gray mold diseases on rose plants (Rosa hybrida L.) were examined by two experiments conducted in a growth chamber. To classify the healthy and infected plants, feature selection was carried out and the best extracted thermal features with the largest linguistic hedge values were chosen. Two neuro-fuzzy classifiers were trained to distinguish between the healthy and infected plants. Best estimation rates of 92.55% and 92.3% were achieved in training and testing the classifier with 8 clusters in order to identify the leaves infected with powdery mildew. In addition, the best estimation rates of 97.5% and 92.59% were achieved in training and testing the classifier with 4 clusters to identify the gray mold disease on flowers. Performance of the designed neuro-fuzzy classifiers were evaluated with the thermal images captured using an automatic imaging setup. Best correct estimation rates of 69% and 80% were achieved (on the second day post-inoculation) for pre-symptomatic appearance detection of powdery mildew and gray mold diseases, respectively.

  17. Effects of sunlight exposure on grapevine powdery mildew development.

    Science.gov (United States)

    Austin, Craig N; Wilcox, Wayne F

    2012-09-01

    Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

  18. Phenotypic characterization of papaya genotypes to determine powdery mildew resistance

    Directory of Open Access Journals (Sweden)

    Marcelo Vivas

    2017-06-01

    Full Text Available In support of breeding of papaya (Carica papaya, the disease incidence and severity of powdery mildew (Ovulariopsis caricicola were evaluated in papaya genotypes. Two experiments in complete randomized blocks were carried out, one in the field and the other in a greenhouse. In field experiments, the lowest mean disease incidence was observed on the genotypes ‘Costa Rica’ and ‘Baixinho Super’, and the lowest mean disease severity on ‘Caliman M5’, ‘GTF’, ‘SH 11-08’, and ‘JS 11’. In the greenhouse experiment, the genotypes ‘Caliman M5’, ‘Golden’, ‘Kapoho Solo’, ‘Waimanalo’, ‘Mamão Bené’, ‘SH 12-07’, ‘JS 12’, and ‘GTF’ had the lowest mean incidence in at least one evaluation. On the other hand, for severity, the genotypes ‘Diva’, ‘Sunrise Solo 72/12’, ‘Kapoho Solo PA’, ‘Waimanalo’, ‘Maradol’, ‘Maradol GL’, ‘SH 15-04’, ‘FMV, ‘JS 12-4’, ‘SH 12-07’ and ‘Sekati FLM’ had the lowest means. These results indicate these genotypes for a possible use in breeding for reduction of powdery mildew intensity

  19. Genomic identification, phylogeny, and expression analysis of MLO genes involved in susceptibility to powdery mildew in Fragaria vesca.

    Science.gov (United States)

    Miao, L X; Jiang, M; Zhang, Y C; Yang, X F; Zhang, H Q; Zhang, Z F; Wang, Y Z; Jiang, G H

    2016-08-05

    The MLO (powdery mildew locus O) gene family is important in resistance to powdery mildew (PM). In this study, all of the members of the MLO family were identified and analyzed in the strawberry (Fragaria vesca) genome. The strawberry contains at least 20 members of the MLO family, and the protein sequence contained between 171 and 1485 amino acids, with 0-34 introns. Chromosomal localization showed that the MLOs were unevenly distributed on each of the chromosomes, except for chromosome 4. The greatest number of MLOs (seven) was found on chromosome 3. A phylogenetic tree showed that the MLOs were divided into seven groups (I-VII), four of which consisted of MLOs from strawberry, Arabidopsis thaliana, rice, and maize, suggesting that these genes may have evolved after the divergence of monocots and dicots. Multiple sequence alignment showed that strawberry MLO candidates related to powdery mildew resistance possessed seven highly conserved transmembrane domains, a calmodulin-binding domain, and two conserved regions, all of which are important domains for powdery mildew resistance genes. Expressed sequence tag analysis revealed that the MLOs were induced by multiple abiotic stressors, including low and high temperature, drought, and high salinity. These findings will contribute to the functional characterization of MLOs related to PM susceptibility, and will assist in the development of disease resistance in strawberries.

  20. Two major er1 alleles confer powdery mildew resistance in three pea cultivars bred in Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    Suli Sun; Yuhua He; Cheng Dai; Canxing Duan; Zhendong Zhu

    2016-01-01

    Powdery mildew, caused by Erysiphe pisi D.C., is an important disease of pea (Pisum sativum L.). The use of cultivars carrying powdery mildew resistance alleles at the er1 locus is the most effective and economical means of controlling this disease. The objectives of this study were to screen Chinese elite pea cultivars for resistance to E. pisi and to identify the responsible gene at the er1 locus. Among the 37 pea cultivars tested, three (Yunwan 8, Yunwan 21, and Yunwan 23) were immune to E. pisi infection in phenotypic evaluations. The full-length cDNA sequences of the er1 candidate gene, PsMLO1, from the three resistant cultivars and control plants were analyzed. Comparison of the cDNA sequences of 10 clones revealed differences among the powdery mildew-resistant cultivars, susceptible controls, and wild-type cultivar Sprinter. The observed resistance in Yunwan 8 plants resulted from a point mutation (C→G) at position 680 of PsMLO1 that introduced a stop codon, leading to premature termination of protein synthesis. The responsible resistance allele was identified as er1–1. Powdery mildew resistance in Yunwan 21 and Yunwan 23 plants was caused by identical insertions or deletions in PsMLO1. Three distinct PsMLO1 transcripts were observed in Yunwan 21 and Yunwan 23 plants. These transcripts were characterized by a 129-bp deletion and 155-and 220-bp insertions, respectively. The responsible resistance allele was identified as er1–2. We have characterized two important er1 alleles in three E. pisi-resistant pea cultivars bred in Yunnan Province, China. These cultivars represent important genetic resources for the breeding of powdery mildew-resistant pea cultivars.

  1. Two major er1 alleles confer powdery mildew resistance in three pea cultivars bred in Yunnan Province, China

    Directory of Open Access Journals (Sweden)

    Suli Sun

    2016-10-01

    Full Text Available Powdery mildew, caused by Erysiphe pisi D.C., is an important disease of pea (Pisum sativum L.. The use of cultivars carrying powdery mildew resistance alleles at the er1 locus is the most effective and economical means of controlling this disease. The objectives of this study were to screen Chinese elite pea cultivars for resistance to E. pisi and to identify the responsible gene at the er1 locus. Among the 37 pea cultivars tested, three (Yunwan 8, Yunwan 21, and Yunwan 23 were immune to E. pisi infection in phenotypic evaluations. The full-length cDNA sequences of the er1 candidate gene, PsMLO1, from the three resistant cultivars and control plants were analyzed. Comparison of the cDNA sequences of 10 clones revealed differences among the powdery mildew-resistant cultivars, susceptible controls, and wild-type cultivar Sprinter. The observed resistance in Yunwan 8 plants resulted from a point mutation (C → G at position 680 of PsMLO1 that introduced a stop codon, leading to premature termination of protein synthesis. The responsible resistance allele was identified as er1–1. Powdery mildew resistance in Yunwan 21 and Yunwan 23 plants was caused by identical insertions or deletions in PsMLO1. Three distinct PsMLO1 transcripts were observed in Yunwan 21 and Yunwan 23 plants. These transcripts were characterized by a 129-bp deletion and 155- and 220-bp insertions, respectively. The responsible resistance allele was identified as er1–2. We have characterized two important er1 alleles in three E. pisi-resistant pea cultivars bred in Yunnan Province, China. These cultivars represent important genetic resources for the breeding of powdery mildew-resistant pea cultivars.

  2. Transcriptome sequencing in a Tibetan barley landrace with high resistance to powdery mildew.

    Science.gov (United States)

    Zeng, Xing-Quan; Luo, Xiao-Mei; Wang, Yu-Lin; Xu, Qi-Jun; Bai, Li-Jun; Yuan, Hong-Jun; Tashi, Nyima

    2014-01-01

    Hulless barley is an important cereal crop worldwide, especially in Tibet of China. However, this crop is usually susceptible to powdery mildew caused by Blumeria graminis f. sp. hordei. In this study, we aimed to understand the functions and pathways of genes involved in the disease resistance by transcriptome sequencing of a Tibetan barley landrace with high resistance to powdery mildew. A total of 831 significant differentially expressed genes were found in the infected seedlings, covering 19 functions. Either "cell," "cell part," and "extracellular region" in the cellular component category or "binding" and "catalytic" in the category of molecular function as well as "metabolic process" and "cellular process" in the biological process category together demonstrated that these functions may be involved in the resistance to powdery mildew of the hulless barley. In addition, 330 KEGG pathways were found using BLASTx with an E-value cut-off of powdery mildew infection.

  3. Identification and mapping of two powdery mildew resistance genes in Triticum boeoticum L.

    Science.gov (United States)

    Chhuneja, Parveen; Kumar, Krishan; Stirnweis, Daniel; Hurni, Severine; Keller, Beat; Dhaliwal, Harcharan S; Singh, Kuldeep

    2012-04-01

    Powdery mildew (PM) caused by Blumeria graminis f. sp. tritici (Bgt), is one of the important foliar diseases of wheat that can cause serious yield losses. Breeding for cultivars with diverse resources of resistance is the most promising approach for combating this disease. The diploid A genome progenitor species of wheat are an important resource for new variability for disease resistance genes. An accession of Triticum boeoticum (A(b)A(b)) showed resistance against a number of Bgt isolates, when tested using detached leaf segments. Inheritance studies in a recombinant inbred line population (RIL), developed from crosses of PM resistant T. boeoticum acc. pau5088 with a PM susceptible T. monococcum acc. pau14087, indicated the presence of two powdery mildew resistance genes in T. boeoticum acc. pau5088. Analysis of powdery mildew infection and molecular marker data of the RIL population revealed that both powdery mildew resistance genes are located on the long arm of chromosome 7A. Mapping was conducted using an integrated linkage map of 7A consisting of SSR, RFLP, STS, and DArT markers. These powdery mildew resistance genes are tentatively designated as PmTb7A.1 and PmTb7A.2. The PmTb7A.2 is closely linked to STS markers MAG2185 and MAG1759 derived from RFLP probes which are linked to powdery mildew resistance gene Pm1. This indicated that PmTb7A.2 might be allelic to Pm1. The PmTb7A.1, flanked by a DArT marker wPt4553 and an SSR marker Xcfa2019 in a 4.3 cM interval, maps proximal to PmT7A.2. PmTb7A.1 is putatively a new powdery mildew resistance gene. The powdery mildew resistance genes from T. boeoticum are currently being transferred to cultivated wheat background through marker-assisted backcrossing, using T. durum as bridging species.

  4. Biological control mechanisms of D-pinitol against powdery mildew in cucumber

    OpenAIRE

    Chen, J; Fernandez, Diana; Wang, D. D.; Chen, Y. J.; Dai, G. H.

    2014-01-01

    D-pinitol is an effective agent for controlling powdery mildew (Podosphaera xanthii) in cucumber. In this study, we determined the mechanisms of D-pinitol in controlling powdery mildew in cucumber plants. We compared P. xanthii development on cucumber leaf surface treated with D-pinitol or water (2 mg ml(-1)) at different time points after inoculation. The germinating conidia, hyphae, and conidiophores of the pathogen were severely damaged by D-pinitol at any time of application tested. The h...

  5. Loss of function in Mlo orthologs reduces susceptibility of pepper and tomato to powdery mildew disease caused by Leveillula taurica.

    Directory of Open Access Journals (Sweden)

    Zheng Zheng

    Full Text Available Powdery mildew disease caused by Leveillula taurica is a serious fungal threat to greenhouse tomato and pepper production. In contrast to most powdery mildew species which are epiphytic, L. taurica is an endophytic fungus colonizing the mesophyll tissues of the leaf. In barley, Arabidopsis, tomato and pea, the correct functioning of specific homologues of the plant Mlo gene family has been found to be required for pathogenesis of epiphytic powdery mildew fungi. The aim of this study was to investigate the involvement of the Mlo genes in susceptibility to the endophytic fungus L. taurica. In tomato (Solanum lycopersicum, a loss-of-function mutation in the SlMlo1 gene results in resistance to powdery mildew disease caused by Oidium neolycopersici. When the tomato Slmlo1 mutant was inoculated with L. taurica in this study, it proved to be less susceptible compared to the control, S. lycopersicum cv. Moneymaker. Further, overexpression of SlMlo1 in the tomato Slmlo1 mutant enhanced susceptibility to L. taurica. In pepper, the CaMlo2 gene was isolated by applying a homology-based cloning approach. Compared to the previously identified CaMlo1 gene, the CaMlo2 gene is more similar to SlMlo1 as shown by phylogenetic analysis, and the expression of CaMlo2 is up-regulated at an earlier time point upon L. taurica infection. However, results of virus-induced gene silencing suggest that both CaMlo1 and CaMlo2 may be involved in the susceptibility of pepper to L. taurica. The fact that overexpression of CaMlo2 restored the susceptibility of the tomato Slmlo1 mutant to O. neolycopersici and increased its susceptibility to L. taurica confirmed the role of CaMlo2 acting as a susceptibility factor to different powdery mildews, though the role of CaMlo1 as a co-factor for susceptibility cannot be excluded.

  6. RFLP Tagging of a Gene Pm12 for Powdery Mildew Resistance in Wheat (Triticum aestivum L. )

    Institute of Scientific and Technical Information of China (English)

    贾继增; T.E.Miller; S.M.Reader; M.D.Gale

    1994-01-01

    A dominant gene, Pml2, conferring the resistance to powdery mildew (Erysiphe graminis) has been transferred to wheat from Aegilops speltoides. Sixteen RFLP probes were used to test Line 31 and its parents, showing that Line 31 is a 6B/6S translocation lines. The linkage analysis by five probes indicates that Pm12 is located on the chromosome 6B/6S, and tightly flanked by an RFLP marker α-Amy-1 (1.1 cM), identified by RFLP and isozyme analysis. This approach is equally applicable to the identification of other transferred alien genes and the segments of alien chromosome introgressed into wheat.

  7. A transgenic wheat with a stilbene synthase gene resistant to powdery mildew obtained by biolistic method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Stilbene, a kind of phytoalexin, plays an important role in resistance to fungal and bacterial infection in plants. It strongly inhibits the growth of fungi and sprout of spore. Stilbene synthase gene (Vst1) obtained from grapevine has been transferred into common spring wheat Jinghong 5 by using the biolistic transformation method. Five transgenic plants (T0) were obtained from the bombarded 2014 immature embryos. One immune plantlet and 3 plantlets with mid-resistance to powdery mildew were identified from the transgenic plants of T3 generation which came from 2 T0 transgenic plants.

  8. MECHANISMS INVOLVED IN MYCORRHIZAL WHEAT PROTECTION AGAINST POWDERY MILDEW.

    Science.gov (United States)

    Mustafa, G; Tisserant, B; Randoux, B; Fontaine, J; Sahraoui, A Lounes-Hadj; Reignault, Ph

    2014-01-01

    In France, the Ecophyto 2018 national action plan will set out to reduce the use of pesticides by 50% by 2018, if possible. To achieve this goal, the use of arbuscular mycorrhizal (AM) fungi could be a potential alternative method allowing the control of crop diseases. The inoculation by AM fungi has been demonstrated to protect plants against soil-borne pathogens, but little is known about their effectiveness against aerial pathogens, such as the biotrophic fungus Blumeria graminis f.sp. tritici (Bgt) causing wheat (Triticum aestivum) powdery mildew. In the present study, wheat plants were grown in pots, under controlled conditions. Using various phosphorus (P) concentrations, the effectiveness of three AM inocula (Rhizophagus irregularis (Ri), Funneliformis mosseae (Fm)) and Solrize, a mixture of Ri and Fm) in Orvantis wheat cultivar, were tested. After 42 days of culture, mycorrhizal (M) and non-mycorrhizal (NM) wheat plants were infected by Bgt. A satisfactory mycorrhizal rate was obtained with the phosphorus concentration P/5 (P corresponding to the dose used in wheat fields in = 62 mg/L). Our work shows, for the first time, (i) a protective effect of AM inoculation against wheat powdery mildew, reaching up to 73% with Fm inocula, and (ii) its ability to induce a systemic resistance in wheat. Thereafter, we investigated mechanisms involved in this protection. Control plants, M plants, infected plants by Bgt, and M-infected plants were compared at: (i) cytological level, our results revealed that papillae and whole-fluorescent cells presence was induced, conversely fungal haustorium formation in epidermal cells was reduced within M plants leaves (ii) enzymatic level-by assessing defense enzyme activities (lipoxygenase, peroxidase) known as defense markers were measured 24, 48, 72 and 96 hours after infection (hai). The importance of these activities in the defense pathways induced in wheat by AM fungi will be discussed.

  9. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle.

    Science.gov (United States)

    Tabata, Jun; De Moraes, Consuelo M; Mescher, Mark C

    2011-01-01

    Powdery mildews (Erysiphales) are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae) feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata) infected by powdery mildew (Podosphaera sp.) and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata) to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.

  10. Monitoring powdery mildew of winter wheat by using moderate resolution multi-temporal satellite imagery.

    Directory of Open Access Journals (Sweden)

    Jingcheng Zhang

    Full Text Available Powdery mildew is one of the most serious diseases that have a significant impact on the production of winter wheat. As an effective alternative to traditional sampling methods, remote sensing can be a useful tool in disease detection. This study attempted to use multi-temporal moderate resolution satellite-based data of surface reflectances in blue (B, green (G, red (R and near infrared (NIR bands from HJ-CCD (CCD sensor on Huanjing satellite to monitor disease at a regional scale. In a suburban area in Beijing, China, an extensive field campaign for disease intensity survey was conducted at key growth stages of winter wheat in 2010. Meanwhile, corresponding time series of HJ-CCD images were acquired over the study area. In this study, a number of single-stage and multi-stage spectral features, which were sensitive to powdery mildew, were selected by using an independent t-test. With the selected spectral features, four advanced methods: mahalanobis distance, maximum likelihood classifier, partial least square regression and mixture tuned matched filtering were tested and evaluated for their performances in disease mapping. The experimental results showed that all four algorithms could generate disease maps with a generally correct distribution pattern of powdery mildew at the grain filling stage (Zadoks 72. However, by comparing these disease maps with ground survey data (validation samples, all of the four algorithms also produced a variable degree of error in estimating the disease occurrence and severity. Further, we found that the integration of MTMF and PLSR algorithms could result in a significant accuracy improvement of identifying and determining the disease intensity (overall accuracy of 72% increased to 78% and kappa coefficient of 0.49 increased to 0.59. The experimental results also demonstrated that the multi-temporal satellite images have a great potential in crop diseases mapping at a regional scale.

  11. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle.

    Directory of Open Access Journals (Sweden)

    Jun Tabata

    Full Text Available Powdery mildews (Erysiphales are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata infected by powdery mildew (Podosphaera sp. and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.

  12. mlo-based powdery mildew resistance in hexaploid bread wheat generated by a non-transgenic TILLING approach.

    Science.gov (United States)

    Acevedo-Garcia, Johanna; Spencer, David; Thieron, Hannah; Reinstädler, Anja; Hammond-Kosack, Kim; Phillips, Andrew L; Panstruga, Ralph

    2017-03-01

    Wheat is one of the most widely grown cereal crops in the world and is an important food grain source for humans. However, wheat yields can be reduced by many abiotic and biotic stress factors, including powdery mildew disease caused by Blumeria graminis f.sp. tritici (Bgt). Generating resistant varieties is thus a major effort in plant breeding. Here, we took advantage of the non-transgenic Targeting Induced Lesions IN Genomes (TILLING) technology to select partial loss-of-function alleles of TaMlo, the orthologue of the barley Mlo (Mildew resistance locus o) gene. Natural and induced loss-of-function alleles (mlo) of barley Mlo are known to confer durable broad-spectrum powdery mildew resistance, typically at the expense of pleiotropic phenotypes such as premature leaf senescence. We identified 16 missense mutations in the three wheat TaMlo homoeologues, TaMlo-A1, TaMlo-B1 and TaMlo-D1 that each lead to single amino acid exchanges. Using transient gene expression assays in barley single cells, we functionally analysed the different missense mutants and identified the most promising candidates affecting powdery mildew susceptibility. By stacking of selected mutant alleles we generated four independent lines with non-conservative mutations in each of the three TaMlo homoeologues. Homozygous triple mutant lines and surprisingly also some of the homozygous double mutant lines showed enhanced, yet incomplete, Bgt resistance without the occurrence of discernible pleiotropic phenotypes. These lines thus represent an important step towards the production of commercial non-transgenic, powdery mildew-resistant bread wheat varieties.

  13. Studies on biological control of powdery mildew in cucumber (Sphaerotheca fuliginea) and rose (Sphaerotheca pannosa) by means of mycoparasites.

    NARCIS (Netherlands)

    Verhaar, M.A.

    1998-01-01

    Powdery mildew on rose ( Sphaerotheca pannosa ) and cucumber ( Sphaerotheca fuliginea ) are two serious diseases in glasshouses. Intensive control by fungicides is needed. The research presented here deals with biocontrol of powdery mildew on cucumber and rose by means of mycoparasites.The mycoparas

  14. Pea powdery mildew er1 resistance is associated to loss-of-function mutations at a MLO homologous locus

    NARCIS (Netherlands)

    Pavan, S.N.C.; Schiavulli, A.; Appiano, M.; Visser, R.G.F.; Bai, Y.

    2011-01-01

    The powdery mildew disease affects several crop species and is also one of the major threats for pea (Pisum sativum L.) cultivation all over the world. The recessive gene er1, first described over 60 years ago, is well known in pea breeding, as it still maintains its efficiency as a powdery mildew

  15. Transcriptomes That Confer to Plant Defense against Powdery Mildew Disease in Lagerstroemia indica

    Directory of Open Access Journals (Sweden)

    Xinwang Wang

    2015-01-01

    Full Text Available Transcriptome analysis was conducted in two popular Lagerstroemia cultivars: “Natchez” (NAT, a white flower and powdery mildew resistant interspecific hybrid and “Carolina Beauty” (CAB, a red flower and powdery mildew susceptible L. indica cultivar. RNA-seq reads were generated from Erysiphe australiana infected leaves and de novo assembled. A total of 37,035 unigenes from 224,443 assembled contigs in both genotypes were identified. Approximately 85% of these unigenes have known function. Of them, 475 KEGG genes were found significantly different between the two genotypes. Five of the top ten differentially expressed genes (DEGs involved in the biosynthesis of secondary metabolites (plant defense and four in flavonoid biosynthesis pathway (antioxidant activities or flower coloration. Furthermore, 5 of the 12 assembled unigenes in benzoxazinoid biosynthesis and 7 of 11 in flavonoid biosynthesis showed higher transcript abundance in NAT. The relative abundance of transcripts for 16 candidate DEGs (9 from CAB and 7 from NAT detected by qRT-PCR showed general agreement with the abundances of the assembled transcripts in NAT. This study provided the first transcriptome analyses in L. indica. The differential transcript abundance between two genotypes indicates that it is possible to identify candidate genes that are associated with the plant defenses or flower coloration.

  16. Application of Glycerol for Induced Powdery Mildew Resistance in Triticum aestivum L.

    Science.gov (United States)

    Li, Yinghui; Song, Na; Zhao, Chuanzhi; Li, Feng; Geng, Miaomiao; Wang, Yuhui; Liu, Wanhui; Xie, Chaojie; Sun, Qixin

    2016-01-01

    Previous work has demonstrated that glycerol-3-phosphate (G3P) and oleic acid (18:1) are two important signal molecules associated with plant resistance to fungi. In this article, we provide evidence that a 3% glycerol spray application 1-2 days before powdery mildew infection and subsequent applications once every 4 days was sufficient to stimulate the plant defense responses without causing any significant damage to wheat leaves. We found that G3P and oleic acid levels were markedly induced by powdery mildew infection. In addition, TaGLI1 (encoding a glycerol kinase) and TaSSI2 (encoding a stearoylacyl carrier protein fatty acid desaturase), two genes associated with the glycerol and fatty acid (FA) pathways, respectively, were induced by powdery mildew infection, and their promoter regions contain some fungal response elements. Moreover, exogenous application of glycerol increased the G3P level and decreased the level of oleic acid (18:1). Glycerol application induced the expression of pathogenesis-related (PR) genes (TaPR-1, TaPR-2, TaPR-3, TaPR-4, and TaPR-5), induced the generation of reactive oxygen species (ROS) before powdery mildew infection, and induced salicylic acid (SA) accumulation in wheat leaves. Further, we sprayed glycerol in a wheat field and found that it significantly (p powdery mildew disease and lessened disease-associated kernel weight loss, all without causing any noticeable degradation in wheat seed quality.

  17. Biotrophy at Its Best: Novel Findings and Unsolved Mysteries of the Arabidopsis-Powdery Mildew Pathosystem.

    Science.gov (United States)

    Kuhn, Hannah; Kwaaitaal, Mark; Kusch, Stefan; Acevedo-Garcia, Johanna; Wu, Hongpo; Panstruga, Ralph

    2016-01-01

    It is generally accepted in plant-microbe interactions research that disease is the exception rather than a common outcome of pathogen attack. However, in nature, plants with symptoms that signify colonization by obligate biotrophic powdery mildew fungi are omnipresent. The pervasiveness of the disease and the fact that many economically important plants are prone to infection by powdery mildew fungi drives research on this interaction. The competence of powdery mildew fungi to establish and maintain true biotrophic relationships renders the interaction a paramount example of a pathogenic plant-microbe biotrophy. However, molecular details underlying the interaction are in many respects still a mystery. Since its introduction in 1990, the Arabidopsis-powdery mildew pathosystem has become a popular model to study molecular processes governing powdery mildew infection. Due to the many advantages that the host Arabidopsis offers in terms of molecular and genetic tools this pathosystem has great capacity to answer some of the questions of how biotrophic pathogens overcome plant defense and establish a persistent interaction that nourishes the invader while in parallel maintaining viability of the plant host.

  18. Serine/threonine kinase gene Stpk-V, a key member of powdery mildew resistance gene Pm21, confers powdery mildew resistance in wheat.

    Science.gov (United States)

    Cao, Aizhong; Xing, Liping; Wang, Xiaoyun; Yang, Xueming; Wang, Wei; Sun, Yulei; Qian, Chen; Ni, Jinlong; Chen, Yaping; Liu, Dajun; Wang, Xiue; Chen, Peidu

    2011-05-10

    Powdery mildew resistance gene Pm21, located on the chromosome 6V short arm of Haynaldia villosa and transferred to wheat as a 6VS·6AL translocation (T6VS·6AL), confers durable and broad-spectrum resistance to wheat powdery mildew. Pm21 has become a key gene resource for powdery mildew resistance breeding all over the world. In China, 12 wheat varieties containing Pm21 have been planted on more than 3.4 million hectares since 2002. Pm21 has been intractable to molecular genetic mapping because the 6VS does not pair and recombine with the 6AS. Moreover, all known accessions of H. villosa are immune to powdery mildew fungus. Pm21 is still defined by cytogenetics as a locus. In the present study, a putative serine and threonine protein kinase gene Stpk-V was cloned and characterized with an integrative strategy of molecular and cytogenetic techniques. Stpk-V is located on the Pm21 locus. The results of a single cell transient expression assay showed that Stpk-V could decrease the haustorium index dramatically. After the Stpk-V was transformed into a susceptible wheat variety Yangmai158, the characterized transgenic plants showed high and broad-spectrum powdery mildew resistance similar to T6VS·6AL. Silencing of the Stpk-V by virus-induced gene silencing in both T6VS·6AL and H. villosa resulted in their increased susceptibility. Stpk-V could be induced by Bgt and exogenous H(2)O(2), but it also mediated the increase of endogenous H(2)O(2), leading to cell death and plant resistance when the plant was attacked by Bgt.

  19. QTL identification in an interspecific grapevine cross segregating for resistance to Powdery Mildew, Downy Mildew, Black Rot, and Phylloxera

    Science.gov (United States)

    Grapevine is a highly heterozygous plant with a complex genetic background. Here, we report the use of an F1 family (N = 125) from a cross of MN1264 × MN1246 made in 2010. The cross contains at least six Vitis species in its ancestry and segregates for resistance to powdery mildew (Erysiphe necator)...

  20. Map - vs. homology - based cloning for the recessive gene ol-2 conferring resistance to tomato powdery mildew

    OpenAIRE

    Pavan, S.N.C.; Zheng, Z.; Borisova, M.; Berg, van den, G.J.; Lotti, C.; Giovanni, , da Bergamo; Lindhout, P.; de Jong; Ricciardi, L.; Visser, R.G.F.; Bai, Y.

    2008-01-01

    The recessive gene ol-2 confers papilla-associated and race-non-specific resistance to tomato powdery mildew caused by Oidium neolycopersici. In order to facilitate marker assisted selection (MAS) in practical breeding programmes, we identified two simple sequence repeat (SSR) markers and one cleaved amplified polymorphic sequence (CAPS) marker which are linked to the resistance locus and co-dominantly inherited. Aiming to provide a base for ol-2 positional cloning, we used a large segregatin...

  1. Proteomic analysis of the compatible interaction of wheat and powdery mildew (Blumeria graminis f. sp. tritici).

    Science.gov (United States)

    Li, Jie; Yang, Xiwen; Liu, Xinhao; Yu, Haibo; Du, Congyang; Li, Mengda; He, Dexian

    2017-02-01

    Proteome characteristics of wheat leaves with the powdery mildew pathogen Blumeria graminis f. sp. tritici (Bgt) infection were investigated by two-dimensional electrophoresis and tandem MALDI-TOF/TOF-MS. We identified 46 unique proteins which were differentially expressed at 24, 48, and 72 h post-inoculation. The functional classification of these proteins showed that most of them were involved in photosynthesis, carbohydrate and nitrogen metabolism, defense responses, and signal transduction. Upregulated proteins included primary metabolism pathways and defense responses, while proteins related to photosynthesis and signal transduction were mostly downregulated. As expected, more antioxidative proteins were activated at the later infection stage than the earlier stage, suggesting that the antioxidative system of host plays a role in maintaining the compatible interaction between wheat and powdery mildew. A high accumulation of 6-phosphogluconate dehydrogenase and isocitrate dehydrogenase in infected leaves indicated the regulation of the TCA cycle and pentose phosphate pathway in parallel to the activation of host defenses. The downregulation of MAPK5 could be facilitated for the compatible interaction of wheat plants and Bgt. qRT-PCR analysis supported the data of protein expression profiles. Our results reveal the relevance of primary plant metabolism and defense responses during compatible interaction, and provide new insights into the biology of susceptible wheat in response to Bgt infection.

  2. Whole Genome Re-Sequencing and Characterization of Powdery Mildew Disease-Associated Allelic Variation in Melon.

    Directory of Open Access Journals (Sweden)

    Sathishkumar Natarajan

    Full Text Available Powdery mildew is one of the most common fungal diseases in the world. This disease frequently affects melon (Cucumis melo L. and other Cucurbitaceous family crops in both open field and greenhouse cultivation. One of the goals of genomics is to identify the polymorphic loci responsible for variation in phenotypic traits. In this study, powdery mildew disease assessment scores were calculated for four melon accessions, 'SCNU1154', 'Edisto47', 'MR-1', and 'PMR5'. To investigate the genetic variation of these accessions, whole genome re-sequencing using the Illumina HiSeq 2000 platform was performed. A total of 754,759,704 quality-filtered reads were generated, with an average of 82.64% coverage relative to the reference genome. Comparisons of the sequences for the melon accessions revealed around 7.4 million single nucleotide polymorphisms (SNPs, 1.9 million InDels, and 182,398 putative structural variations (SVs. Functional enrichment analysis of detected variations classified them into biological process, cellular component and molecular function categories. Further, a disease-associated QTL map was constructed for 390 SNPs and 45 InDels identified as related to defense-response genes. Among them 112 SNPs and 12 InDels were observed in powdery mildew responsive chromosomes. Accordingly, this whole genome re-sequencing study identified SNPs and InDels associated with defense genes that will serve as candidate polymorphisms in the search for sources of resistance against powdery mildew disease and could accelerate marker-assisted breeding in melon.

  3. Whole Genome Re-Sequencing and Characterization of Powdery Mildew Disease-Associated Allelic Variation in Melon.

    Science.gov (United States)

    Natarajan, Sathishkumar; Kim, Hoy-Taek; Thamilarasan, Senthil Kumar; Veerappan, Karpagam; Park, Jong-In; Nou, Ill-Sup

    2016-01-01

    Powdery mildew is one of the most common fungal diseases in the world. This disease frequently affects melon (Cucumis melo L.) and other Cucurbitaceous family crops in both open field and greenhouse cultivation. One of the goals of genomics is to identify the polymorphic loci responsible for variation in phenotypic traits. In this study, powdery mildew disease assessment scores were calculated for four melon accessions, 'SCNU1154', 'Edisto47', 'MR-1', and 'PMR5'. To investigate the genetic variation of these accessions, whole genome re-sequencing using the Illumina HiSeq 2000 platform was performed. A total of 754,759,704 quality-filtered reads were generated, with an average of 82.64% coverage relative to the reference genome. Comparisons of the sequences for the melon accessions revealed around 7.4 million single nucleotide polymorphisms (SNPs), 1.9 million InDels, and 182,398 putative structural variations (SVs). Functional enrichment analysis of detected variations classified them into biological process, cellular component and molecular function categories. Further, a disease-associated QTL map was constructed for 390 SNPs and 45 InDels identified as related to defense-response genes. Among them 112 SNPs and 12 InDels were observed in powdery mildew responsive chromosomes. Accordingly, this whole genome re-sequencing study identified SNPs and InDels associated with defense genes that will serve as candidate polymorphisms in the search for sources of resistance against powdery mildew disease and could accelerate marker-assisted breeding in melon.

  4. The Wheat Mediator Subunit TaMED25 Interacts with the Transcription Factor TaEIL1 to Negatively Regulate Disease Resistance against Powdery Mildew.

    Science.gov (United States)

    Liu, Jie; Zhang, Tianren; Jia, Jizeng; Sun, Jiaqiang

    2016-03-01

    Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici, is a major limitation for the production of bread wheat (Triticum aestivum). However, to date, the transcriptional regulation of bread wheat defense against powdery mildew remains largely unknown. Here, we report the function and molecular mechanism of the bread wheat Mediator subunit 25 (TaMED25) in regulating the bread wheat immune response signaling pathway. Three homoalleles of TaMED25 from bread wheat were identified and mapped to chromosomes 5A, 5B, and 5D, respectively. We show that knockdown of TaMED25 by barley stripe mosaic virus-induced gene silencing reduced bread wheat susceptibility to the powdery mildew fungus during the compatible plant-pathogen interaction. Moreover, our results indicate that MED25 may play a conserved role in regulating bread wheat and barley (Hordeum vulgare) susceptibility to powdery mildew. Similarly, bread wheat ETHYLENE INSENSITIVE3-LIKE1 (TaEIL1), an ortholog of Arabidopsis (Arabidopsis thaliana) ETHYLENE INSENSITIVE3, negatively regulates bread wheat resistance against powdery mildew. Using various approaches, we demonstrate that the conserved activator-interacting domain of TaMED25 interacts physically with the separate amino- and carboxyl-terminal regions of TaEIL1, contributing to the transcriptional activation activity of TaEIL1. Furthermore, we show that TaMED25 and TaEIL1 synergistically activate ETHYLENE RESPONSE FACTOR1 (TaERF1) transcription to modulate bread wheat basal disease resistance to B. graminis f. sp. tritici by repressing the expression of pathogenesis-related genes and deterring the accumulation of reactive oxygen species. Collectively, we identify the TaMED25-TaEIL1-TaERF1 signaling module as a negative regulator of bread wheat resistance to powdery mildew.

  5. No indication of strict host associations in a widespread mycoparasite: grapevine powdery mildew (Erysiphe necator) is attacked by phylogenetically distant Ampelomyces strains in the field.

    Science.gov (United States)

    Pintye, Alexandra; Bereczky, Zsolt; Kovács, Gábor M; Nagy, László G; Xu, Xiangming; Legler, Sara Elisabetta; Váczy, Zsuzsanna; Váczy, Kálmán Zoltán; Caffi, Tito; Rossi, Vittorio; Kiss, Levente

    2012-07-01

    Pycnidial fungi belonging to the genus Ampelomyces are common intracellular mycoparasites of powdery mildews worldwide. Some strains have already been developed as commercial biocontrol agents (BCAs) of Erysiphe necator and other powdery mildew species infecting important crops. One of the basic, and still debated, questions concerning the tritrophic relationships between host plants, powdery mildew fungi, and Ampelomyces mycoparasites is whether Ampelomyces strains isolated from certain species of the Erysiphales are narrowly specialized to their original mycohosts or are generalist mycoparasites of many powdery mildew fungi. This is also important for the use of Ampelomyces strains as BCAs. To understand this relationship, the nuclear ribosomal DNA internal transcribed spacer (ITS) and partial actin gene (act1) sequences of 55 Ampelomyces strains from E. necator were analyzed together with those of 47 strains isolated from other powdery mildew species. These phylogenetic analyses distinguished five major clades and strains from E. necator that were present in all but one clade. This work was supplemented with the selection of nine inter-simple sequence repeat (ISSR) markers for strain-specific identification of Ampelomyces mycoparasites to monitor the environmental fate of strains applied as BCAs. The genetic distances among strains calculated based on ISSR patterns have also highlighted the genetic diversity of Ampelomyces mycoparasites naturally occurring in grapevine powdery mildew. Overall, this work showed that Ampelomyces strains isolated from E. necator are genetically diverse and there is no indication of strict mycohost associations in these strains. However, these results cannot rule out a certain degree of quantitative association between at least some of the Ampelomyces lineages identified in this work and their original mycohosts.

  6. Allelic barley MLA immune receptors recognize sequence-unrelated avirulence effectors of the powdery mildew pathogen.

    Science.gov (United States)

    Lu, Xunli; Kracher, Barbara; Saur, Isabel M L; Bauer, Saskia; Ellwood, Simon R; Wise, Roger; Yaeno, Takashi; Maekawa, Takaki; Schulze-Lefert, Paul

    2016-10-18

    Disease-resistance genes encoding intracellular nucleotide-binding domain and leucine-rich repeat proteins (NLRs) are key components of the plant innate immune system and typically detect the presence of isolate-specific avirulence (AVR) effectors from pathogens. NLR genes define the fastest-evolving gene family of flowering plants and are often arranged in gene clusters containing multiple paralogs, contributing to copy number and allele-specific NLR variation within a host species. Barley mildew resistance locus a (Mla) has been subject to extensive functional diversification, resulting in allelic resistance specificities each recognizing a cognate, but largely unidentified, AVRa gene of the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). We applied a transcriptome-wide association study among 17 Bgh isolates containing different AVRa genes and identified AVRa1 and AVRa13, encoding candidate-secreted effectors recognized by Mla1 and Mla13 alleles, respectively. Transient expression of the effector genes in barley leaves or protoplasts was sufficient to trigger Mla1 or Mla13 allele-specific cell death, a hallmark of NLR receptor-mediated immunity. AVRa1 and AVRa13 are phylogenetically unrelated, demonstrating that certain allelic MLA receptors evolved to recognize sequence-unrelated effectors. They are ancient effectors because corresponding loci are present in wheat powdery mildew. AVRA1 recognition by barley MLA1 is retained in transgenic Arabidopsis, indicating that AVRA1 directly binds MLA1 or that its recognition involves an evolutionarily conserved host target of AVRA1 Furthermore, analysis of transcriptome-wide sequence variation among the Bgh isolates provides evidence for Bgh population structure that is partially linked to geographic isolation.

  7. Genetic dissection of powdery mildew resistance in interspecific half-sib grapevine families using SNP-based maps.

    Science.gov (United States)

    Teh, Soon Li; Fresnedo-Ramírez, Jonathan; Clark, Matthew D; Gadoury, David M; Sun, Qi; Cadle-Davidson, Lance; Luby, James J

    2017-01-01

    Quantitative trait locus (QTL) identification in perennial fruit crops is impeded largely by their lengthy generation time, resulting in costly and labor-intensive maintenance of breeding programs. In a grapevine (genus Vitis) breeding program, although experimental families are typically unreplicated, the genetic backgrounds may contain similar progenitors previously selected due to their contribution of favorable alleles. In this study, we investigated the utility of joint QTL identification provided by analyzing half-sib families. The genetic control of powdery mildew was studied using two half-sib F1 families, namely GE0711/1009 (MN1264 × MN1214; N = 147) and GE1025 (MN1264 × MN1246; N = 125) with multiple species in their ancestry. Maternal genetic maps consisting of 1077 and 1641 single nucleotide polymorphism (SNP) markers, respectively, were constructed using a pseudo-testcross strategy. Ratings of field resistance to powdery mildew were obtained based on whole-plant evaluation of disease severity. This 2-year analysis uncovered two QTLs that were validated on a consensus map in these half-sib families with improved precision relative to the parental maps. Examination of haplotype combinations based on the two QTL regions identified strong association of haplotypes inherited from 'Seyval blanc', through MN1264, with powdery mildew resistance. This investigation also encompassed the use of microsatellite markers to establish a correlation between 206-bp (UDV-015b) and 357-bp (VViv67) fragment sizes with resistance-carrying haplotypes. Our work is one of the first reports in grapevine demonstrating the use of SNP-based maps and haplotypes for QTL identification and tagging of powdery mildew resistance in half-sib families.

  8. Localization of powdery mildew resistance gene Ml-ra on barley chromosome 5

    DEFF Research Database (Denmark)

    Doll, Hans; Jensen, Hans Peter

    1986-01-01

    Evidence is presented that the powdery mildew resistance gene called Ml-(41/145) represents a unique, unnamed locus, which we suggest to be designated Ml-ra with reference to variety 'Ragusa b' [Hordeum vulgare]. Ml-ra is located on the short arm of chormosome 5 near powdery mildew resistance locus...... Ml-a and the seed storage protein loci Hor1 and Hor2. The most likely order of the loci is Hor1, Ml-a, Ml-ra, and Hor2....

  9. Mutation of the Glucosinolate Biosynthesis Enzyme Cytochrome P450 83A1 Monooxygenase Increases Camalexin Accumulation and Powdery Mildew Resistance.

    Science.gov (United States)

    Liu, Simu; Bartnikas, Lisa M; Volko, Sigrid M; Ausubel, Frederick M; Tang, Dingzhong

    2016-01-01

    Small secondary metabolites, including glucosinolates and the major phytoalexin camalexin, play important roles in immunity in Arabidopsis thaliana. We isolated an Arabidopsis mutant with increased resistance to the powdery mildew fungus Golovinomyces cichoracearum and identified a mutation in the gene encoding cytochrome P450 83A1 monooxygenase (CYP83A1), which functions in glucosinolate biosynthesis. The cyp83a1-3 mutant exhibited enhanced defense responses to G. cichoracearum and double mutant analysis showed that this enhanced resistance requires NPR1, EDS1, and PAD4, but not SID2 or EDS5. In cyp83a1-3 mutants, the expression of genes related to camalexin synthesis increased upon G. cichoracearum infection. Significantly, the cyp83a1-3 mutant also accumulated higher levels of camalexin. Decreasing camalexin levels by mutation of the camalexin synthetase gene PAD3 or the camalexin synthesis regulator AtWRKY33 compromised the powdery mildew resistance in these mutants. Consistent with these observations, overexpression of PAD3 increased camalexin levels and enhanced resistance to G. cichoracearum. Taken together, our data indicate that accumulation of higher levels of camalexin contributes to increased resistance to powdery mildew.

  10. Powdery Mildew Resistance in Wheat Cultivar Mv Hombár is Conferred by a New Gene, PmHo.

    Science.gov (United States)

    Komáromi, Judit; Jankovics, Tünde; Fábián, Attila; Puskás, Katalin; Zhang, Zengyan; Zhang, Miao; Li, Hongjie; Jäger, Katalin; Láng, László; Vida, Gyula

    2016-11-01

    A new powdery mildew resistance gene designated as PmHo was identified in 'Mv Hombár' winter wheat, bred in Martonvásár, Hungary. It has exhibited a high level of resistance over the last two decades. Genetic mapping of recombinant inbred lines derived from the cross 'Ukrainka'/Mv Hombár located this gene on chromosome 2AL. The segregation ratio and consistent effect in all environments indicated that PmHo is a major dominant powdery mildew resistance gene. The race-specific nature of resistance in Mv Hombár was shown by the emergence of a single virulent pathotype designated as 51-Ho. This pathotype was, to some extent, able to infect Mv Hombár, developing visible symptoms with sporulating colonies. Microscopic studies revealed that, in incompatible interactions, posthaustorial hypersensitivity reaction was the most prevalent but not exclusive plant defense response in Mv Hombár, and fungal growth was mostly arrested during haustorium formation or in the early stages of colony development. The delayed fungal development of the virulent pathotype 51-Ho may be explained by additional effects of other loci that were also involved in the powdery mildew resistance of Mv Hombár.

  11. Mutation of the glucosinolate biosynthesis enzyme cytochrome P450 83A1 monooxygenase increases camalexin accumulation and powdery mildew resistance

    Directory of Open Access Journals (Sweden)

    Simu eLiu

    2016-03-01

    Full Text Available Small secondary metabolites, including glucosinolates and the major phytoalexin camalexin, play important roles in immunity in Arabidopsis thaliana. We isolated an Arabidopsis mutant with increased resistance to the powdery mildew fungus Golovinomyces cichoracearum and identified a mutation in the gene encoding cytochrome P450 83A1 monooxygenase (CYP83A1, which functions in glucosinolate biosynthesis. The cyp83a1-3 mutant exhibited enhanced defense responses to G. cichoracearum and double mutant analysis showed that this enhanced resistance requires NPR1, EDS1, and PAD4, but not SID2 or EDS5. In cyp83a1-3 mutants, the expression of genes related to camalexin synthesis increased upon G. cichoracearum infection. Significantly, the cyp83a1-3 mutant also accumulated higher levels of camalexin. Decreasing camalexin levels by mutation of the camalexin synthetase gene PAD3 or the camalexin synthesis regulator AtWRKY33 compromised the powdery mildew resistance in these mutants. Consistent with these observations, overexpression of PAD3 increased camalexin levels and enhanced resistance to G. cichoracearum. Taken together, our data indicate that accumulation of higher levels of camalexin contributes to increased resistance to powdery mildew.

  12. New wheat-rye 5DS-4RS·4RL and 4RS-5DS·5DL translocation lines with powdery mildew resistance.

    Science.gov (United States)

    Fu, Shulan; Ren, Zhenglong; Chen, Xiaoming; Yan, Benju; Tan, Feiquan; Fu, Tihua; Tang, Zongxiang

    2014-11-01

    Powdery mildew is one of the serious diseases of wheat (Triticum aestivum L., 2 n = 6 × = 42, genomes AABBDD). Rye (Secale cereale L., 2 n = 2 × = 14, genome RR) offers a rich reservoir of powdery mildew resistant genes for wheat breeding program. However, extensive use of these resistant genes may render them susceptible to new pathogen races because of co-evolution of host and pathogen. Therefore, the continuous exploration of new powdery mildew resistant genes is important to wheat breeding program. In the present study, we identified several wheat-rye addition lines from the progeny of T. aestivum L. Mianyang11 × S. cereale L. Kustro, i.e., monosomic addition lines of the rye chromosomes 4R and 6R; a disomic addition line of 6R; and monotelosomic or ditelosomic addition lines of the long arms of rye chromosomes 4R (4 RL) and 6R (6 RL). All these lines displayed immunity to powdery mildew. Thus, we concluded that both the 4 RL and 6 RL arms of Kustro contain powdery mildew resistant genes. It is the first time to discover that 4 RL arm carries powdery mildew resistant gene. Additionally, wheat lines containing new wheat-rye translocation chromosomes were also obtained: these lines retained a short arm of wheat chromosome 5D (5 DS) on which rye chromosome 4R was fused through the short arm 4 RS (designated 5 DS-4 RS · 4 RL; 4 RL stands for the long arm of rye chromosome 4R); or they had an extra short arm of rye chromosome 4R (4 RS) that was attached to the short arm of wheat chromosome 5D (5 DS) (designated 4 RS-5 DS · 5 DL; 5 DL stands for the long arm of wheat chromosome 5D). These two translocation chromosomes could be transmitted to next generation stably, and the wheat lines containing 5 DS-4 RS · 4 RL chromosome also displayed immunity to powdery mildew. The materials obtained in this study can be used for wheat powdery mildew resistant breeding program.

  13. Hybridization of powdery mildew strains gives rise to pathogens on novel agricultural crop species.

    Science.gov (United States)

    Menardo, Fabrizio; Praz, Coraline R; Wyder, Stefan; Ben-David, Roi; Bourras, Salim; Matsumae, Hiromi; McNally, Kaitlin E; Parlange, Francis; Riba, Andrea; Roffler, Stefan; Schaefer, Luisa K; Shimizu, Kentaro K; Valenti, Luca; Zbinden, Helen; Wicker, Thomas; Keller, Beat

    2016-02-01

    Throughout the history of agriculture, many new crop species (polyploids or artificial hybrids) have been introduced to diversify products or to increase yield. However, little is known about how these new crops influence the evolution of new pathogens and diseases. Triticale is an artificial hybrid of wheat and rye, and it was resistant to the fungal pathogen powdery mildew (Blumeria graminis) until 2001 (refs. 1,2,3). We sequenced and compared the genomes of 46 powdery mildew isolates covering several formae speciales. We found that B. graminis f. sp. triticale, which grows on triticale and wheat, is a hybrid between wheat powdery mildew (B. graminis f. sp. tritici) and mildew specialized on rye (B. graminis f. sp. secalis). Our data show that the hybrid of the two mildews specialized on two different hosts can infect the hybrid plant species originating from those two hosts. We conclude that hybridization between mildews specialized on different species is a mechanism of adaptation to new crops introduced by agriculture.

  14. Antisense expression of peach mildew resistance locus O (PpMlo1) gene confers cross-species resistance to powdery mildew in Fragaria x ananassa.

    Science.gov (United States)

    Jiwan, Derick; Roalson, Eric H; Main, Dorrie; Dhingra, Amit

    2013-12-01

    Powdery mildew (PM) is one of the major plant pathogens. The conventional method of PM control includes frequent use of sulfur-based fungicides adding to production costs and potential harm to the environment. PM remains a major scourge for Rosaceae crops where breeding approaches mainly resort to gene-for-gene resistance. We have tested an alternate source of PM resistance in Rosaceae. Mildew resistance locus O (MLO) has been well studied in barley due to its role in imparting broad spectrum resistance to PM. We identified PpMlo1 (Prunus persica Mlo) in peach and characterized it further to test if a similar mechanism of resistance is conserved in Rosaceae. Due to its recalcitrance in tissue culture, reverse genetic studies involving PpMloI were not feasible in peach. Therefore, Fragaria x ananassa LF9 line, a taxonomic surrogate, was used for functional analysis of PpMlo1. Agrobacterium-mediated transformation yielded transgenic strawberry plants expressing PpMlo1 in sense and antisense orientation. Antisense expression of PpMlo1 in transgenic strawberry plants conferred resistance to Fragaria-specific powdery mildew, Podosphaera macularis. Phylogenetic analysis of 208 putative Mlo gene copies from 35 plant species suggests a large number of duplications of this gene family prior to the divergence of monocots and eudicots, early in eudicot diversification. Our results indicate that the Mlo-based resistance mechanism is functional in Rosaceae, and that Fragaria can be used as a host to test mechanistic function of genes derived from related tree species. To the best of our knowledge, this work is one of the first attempts at testing the potential of using a Mlo-based resistance strategy to combat powdery mildew in Rosaceae.

  15. Durable broad-spectrum powdery mildew resistance in pea er1 plants is conferred by natural loss-of-function mutations in PsMLO1

    NARCIS (Netherlands)

    Humphry, M.; Reinstädler, A.; Ivanov, S.; Bisseling, T.; Panstruga, R.

    2011-01-01

    Loss-of-function alleles of plant-specific MLO (Mildew Resistance Locus O) genes confer broad-spectrum powdery mildew resistance in monocot (barley) and dicot (Arabidopsis thaliana, tomato) plants. Recessively inherited powdery mildew resistance in pea (Pisum sativum) er1 plants is, in many aspects,

  16. Knockdown of MLO genes reduces susceptibility to powdery mildew in grapevine

    NARCIS (Netherlands)

    Pessina, Stefano; Lenzi, Luisa; Perazzolli, Michele; Campa, Manuela; Costa, Dalla Lorenza; Urso, Simona; Valè, Giampiero; Salamini, Francesco; Velasco, Riccardo; Malnoy, Mickael

    2016-01-01

    Erysiphe necator is the causal agent of powdery mildew (PM), one of the most destructive diseases of grapevine. PM is controlled by sulfur-based and synthetic fungicides, which every year are dispersed into the environment. This is why PM-resistant varieties should become a priority for sustainable

  17. Cucurbit powdery mildew of melon incited by Podosphaera xanthii: global and western U.S. perspectives

    Science.gov (United States)

    Cucurbit powdery mildew (CPM) is a major problem of melon (Cucumis melo L.) production worldwide, that is mostly caused by two fungi: Podosphaera xanthii and Golovinomyces cichoracearum (DC) V.P. Heluta (formerly Erysiphe cichoracearum). The two species may co-infect in some areas of northern Europe...

  18. Suppression of cucumber powdery mildew by UV-B is affected by background light quality

    Science.gov (United States)

    Brief (5-10 min) exposure to UV-B radiation (280-300 nm) suppressed powdery mildew (Podosphaera xanthii) on Cucumis sativus. The effect was enhanced by red light (600-660 nm), but offset by blue light (420-500 nm) and UV-A (300-420 nm). Compared to untreated controls, 2 h red light from specific lig...

  19. Quantitative Analysis of the Early Powdery Mildew Infection Stages on Resistant Barley Genotypes

    DEFF Research Database (Denmark)

    Andersen, J. B.; Torp, J.

    1986-01-01

    A classification system was developed, that allowed quantification of the leaf surface development of the barley powdery mildew fungus on barley. An experiment with Manchuria and Pallas as susceptible controls and 4 resistance gene each represented by three lines with different gene backgrounds s...

  20. Cucurbit powdery mildews: Methodology for objective determination and denomination of races

    Science.gov (United States)

    Cucurbit powdery mildew (CPM), a disease on field and greenhouse cucurbit crops worldwide, is caused most frequently by two obligate erysiphaceous ectoparasites (Golovinomyces orontii s.l., Podosphaera xanthii) that are highly variable in their pathogenicity and virulence. Various, independent syste...

  1. Strategies for durable resistance to the grapevine powdery mildew fungus, Erysiphe necator

    Science.gov (United States)

    Nearly all cultivars of Vitis vinifera are highly susceptible to the grapevine powdery mildew fungus, Erysiphe necator. Grape breeders around the world are working to introgress resistance from wild Vitis. Of the widely-used introgressions, most involve dominant, race-specific resistance phenotype...

  2. Powdery mildew suppresses herbivore-induced plant volatiles and interferes with parasitoid attraction in Brassica rapa

    Science.gov (United States)

    The co-occurrence of different antagonists on a plant can greatly affect infochemicals with ecological consequences for higher trophic levels. Here we investigated how the presence of a plant pathogen, the powdery mildew Erysiphe cruciferarum, on Brassica rapa affects 1) plant volatiles emitted in r...

  3. Evaluation of watermelon varieties for tolerance to powdery mildew and Phytophthora fruit rot, 2014

    Science.gov (United States)

    This experiment was conducted at the U.S. Vegetable Laboratory farm in Charleston, SC. The soil was Yonges loamy fine sand. This study was undertaken to determine the performance of seeded and seedless commercial watermelon varieties for tolerance to powdery mildew (PM) and Phytophthora fruit rot as...

  4. Powdery mildew resistant cucurbit rootstocks confer tolerance to grafted susceptible watermelon scions

    Science.gov (United States)

    Cucurbit powdery mildew (PM) caused by Podosphaera xanthii can impact seedling growth and cause serious losses in greenhouse and open fields. We have developed watermelon and bottle gourd germplasm lines with high levels of resistance to PM. A PM susceptible watermelon cultivar Mickey Lee (ML) was g...

  5. Management of Powdery Mildew in Squash by Plant and Alga Extract Biopesticides.

    Science.gov (United States)

    Zhang, Shouan; Mersha, Zelalem; Vallad, Gary E; Huang, Cheng-Hua

    2016-12-01

    Although many fungicides are registered for use to control powdery mildew on cucurbits, management of resistance to fungicides in pathogen populations still remains a major challenge. Two biopesticides Regalia SC and HMO 736 were evaluated in the greenhouse and field for their efficacy against powdery mildew in squash. In greenhouses, Regalia SC alone significantly (P powdery mildew compared to the nontreated control, and was as effective as the chemical standard Procure 480SC (triflumizole). In alternation with Procure 480SC, Regalia SC demonstrated greater or equivalent effects on reducing the disease. HMO 736 alone showed varying levels of disease control, but alternating with Procure 480SC significantly improved control efficacy. In addition, application of Regalia SC or HMO 736 each in alternation with Procure 480SC significantly increased the chlorophyll content in leaves and the total fresh weight of squash plants, when compared with the water control, Regalia SC and HMO 736 alone. In field trials, application of Regalia SC and HMO 736 each alone significantly reduced disease severity in one of two field trials during the early stage of disease development, but not during later stages when disease pressure became high. Both Regalia SC and HMO 736 each applied in alternation with Procure 480SC significantly improved the control efficacy compared to Procure 480SC alone. Results from this study demonstrated that an integrated management program can be developed for powdery mildew in squash by integrating the biopesticides Regalia SC, HMO 736 with the chemical fungicide Procure 480SC.

  6. Tolerance to powdery mildew conferred in susceptible watermelon scion by grafting on resistant rootstocks

    Science.gov (United States)

    Cucurbit powdery mildew (PM) caused by Podosphaera xanthii, can impact seedling growth and cause serious losses in greenhouse and open field production. We have developed several watermelon and bottle gourd germplasm lines with high levels of resistance to PM. A PM susceptible cultivar Mickey Lee ...

  7. Exogenous trehalose induces defenses in wheat before and during a biotic stress caused by powdery mildew.

    Science.gov (United States)

    Tayeh, Christine; Randoux, Béatrice; Vincent, Dorothée; Bourdon, Natacha; Reignault, Philippe

    2014-03-01

    Powdery mildew would be one of the most damaging wheat diseases without the extensive use of conventional fungicides. Some of the alternative control strategies currently emerging are based on the use of resistance inducers. The disacharride trehalose (TR) is classically described as an inducer of defenses in plants to abiotic stress. In this work, the elicitor or priming effect of TR was investigated in wheat both before and during a compatible wheat-powdery mildew interaction through molecular, biochemical, and cytological approaches. In noninoculated conditions, TR elicited the expression of genes encoding chitinase (chi, chi1, and chi4 precursor), pathogenesis-related protein 1, as well as oxalate oxidase (oxo). Moreover, lipid metabolism was shown to be altered by TR spraying via the upregulation of lipoxygenase (lox) and lipid-transfer protein (ltp)-encoding gene expression. On the other hand, the protection conferred by TR to wheat against powdery mildew is associated with the induction of two specific defense markers. Indeed, in infectious conditions following TR spraying, upregulations of chi4 precursor and lox gene expression as well as an induction of the LOX activity were observed. These results are also discussed with regard to the impact of TR on the fungal infectious process, which was shown to be stopped at the appressorial germ tube stage. Our findings strongly suggest that TR is a true inducer of wheat defense and resistance, at least toward powdery mildew.

  8. Functional Analysis of Barley Powdery Mildew Effector Candidates and Identification of their Barley Targets

    DEFF Research Database (Denmark)

    Ahmed, Ali Abdurehim

    The genome of barley powdery mildew fungus (Blumeria graminis f. sp. hordei, Bgh) encodes around 500 Candidate Secreted Effector Proteins (CSEPs), which are believed to be delivered to the barley cells either to interfere with plant defence and/or promote nutrient uptake. So far, little is known...

  9. Meta-analysis reveals a critical period for management of powdery mildew on Hop cones

    Science.gov (United States)

    Results of 28 field trials conducted over a 12-year period investigating management of hop powdery mildew caused by Podosphaera macularis were quantitatively summarized by meta-analysis to compare product efficacy and use patterns by mode of action as defined by Fungicide Resistance Action Committe...

  10. Adaptation to partial resistance to powdery mildew in the hop cultivar Cascade by Podosphaera macularis

    Science.gov (United States)

    The hop cultivar Cascade has been grown in the Pacific Northwestern U.S. with minimal input for management of powdery mildew (Podosphaera macularis) for nearly 20 years due to the putatively quantitative resistance in this cultivar. While partial resistance is generally thought to be more durable th...

  11. Registration of ‘Wyandot-14’ soybean with resistance to soybean aphid and powdery mildew

    Science.gov (United States)

    ‘Wyandot-14’ soybean [Glycine max (L.) Merr.] with resistance to soybean aphid biotypes 1 and 2 and resistance to powdery mildew was jointly released by the USDA-Agricultural Research Service and The Ohio Agricultural Research and Development Center (OARDC) as a late maturity group (MG) II (2.9) foo...

  12. Quantitative trait loci associated with resistance to powdery mildew in cornus florida

    Science.gov (United States)

    Powdery mildew of flowering dogwood (Cornus florida) caused by Erysiphe pulchra is one of the most destructive diseases in nursery production of flowering dogwood throughout the southeastern U.S. Since the mid-1990s, efforts to breed for resistance to the disease have been undertaken, but to-date on...

  13. Editorial: First report of powdery mildew (Oidium sp.) on Pincushion flowers (Scabiosa columbaria) in New York

    NARCIS (Netherlands)

    Jankovics, T.; Kiss, L.; Niks, R.E.; Daughtrey, M.L.

    2009-01-01

    Scabiosa columbaria (Dipsacaceae) is a popular perennial ornamental in the United States. It is native to Europe and was introduced to North America by nursery trade only recently. In the spring of 2006, symptoms of powdery mildew infection were observed on overwintered plants of S. columbaria cv.

  14. Mapping of QTL for resistance to powdery mildew and resistance gene analogues in perennial ryegrass

    DEFF Research Database (Denmark)

    Schejbel, B; Jensen, L B; Asp, T;

    2008-01-01

    The objective of this study was to map resistance gene analogues (RGA) and quantitative trait loci (QTL) for powdery mildew resistance in perennial ryegrass (Lolium perenne L.). The mapping population consisted of 184 F2 genotypes produced from a cross between one genotype of a synthetic perennial...

  15. Identification of genes affecting the response of tomato and Arabidopsis upon powdery mildew infection

    NARCIS (Netherlands)

    Gao, D.

    2014-01-01

      Many plant species are hosts of powdery mildew fungi, including Arabidopsis and economically important crops such as wheat, barley and tomato. Resistance has been explored using induced mutagenesis and natural variation in the plant species. The isolated genes encompass loss-of-function susc

  16. Identification of breeding signatures in grapevine hybrids, donors of resistances against downy and powdery mildew

    NARCIS (Netherlands)

    Vezzulli, S.; Peressotti, E.; Banchi, E.; Dolzani, C.; Micheli, S.; Stefanini, M.; Salamini, F.; Velasco, R.; Riaz, S.; Walker, M.A.; Reisch, B.I.; De Weg, Van W.E.; Bink, M.C.

    2015-01-01

    Grapevine (Vitis vinifera L.) is one of the most valuable crops in the world, but has been often plagued by encountering new parasites that still represent a major constraint, such as downy (DM) and powdery (PM) mildew. Nowadays, growers are still obliged to recur to a massive use of pesticides t

  17. Identification of breeding signatures in grapevine hybrids, donors of resistances against downy and powdery mildew

    NARCIS (Netherlands)

    Vezzulli, S.; Peressotti, E.; Banchi, E.; Dolzani, C.; Micheli, S.; Stefanini, M.; Salamini, F.; Velasco, R.; Riaz, S.; Walker, M.A.; Reisch, B.I.; De Weg, Van W.E.; Bink, M.C.

    2015-01-01

    Grapevine (Vitis vinifera L.) is one of the most valuable crops in the world, but has been often plagued by encountering new parasites that still represent a major constraint, such as downy (DM) and powdery (PM) mildew. Nowadays, growers are still obliged to recur to a massive use of pesticides

  18. Golovinomyces spadaceus causing powdery mildew on Coreopsis hybrid 'Full Moon' (Heliantheae, Asteraceae) in Washington State

    Science.gov (United States)

    Symptoms of powdery mildew were observed on a Coreopsis cultivar in the Horticulture and Landscape Architecture Garden on the Washington State University campus, Pullman, Whitman County, Washington. White to off-white sporulating mycelial areas were ~5mm in diam to confluent and confined to adaxial...

  19. Susceptibility pays off: insights into the mlo-based powdery mildew resistance

    NARCIS (Netherlands)

    Appiano, Michela

    2016-01-01

    Powdery mildew (PM) is a worldwide-occurring plant disease caused by ascomycete fungi of the order Erysiphales. A conspicuous number of plant species are susceptible to this disease, the occurrence of which is increasing due to the influence of climate change. Symptoms are easy to recognize by the p

  20. Confirming resistance in bottle gourd germplasm by quantifying powdery mildew conidia using a cellometer

    Science.gov (United States)

    Powdery mildew (PM) caused by Podosphaera xanthii, an important foliar disease affecting cucurbit crops grown in the United States, commonly occurs on foliage, petioles, and stems. We have developed two highly resistant bottle gourd (Lagenaria siceraria) germplasm (USVL351 and USVL482) for use in o...

  1. Tolerance to Cucurbit Powdery Mildew in USDA Bottle Gourd (Lagenaria siceraria) Plant Introductions (PI)

    Science.gov (United States)

    Powdery mildew (Podosphaera xanthii) can cause severe damage to cucurbit crops grown in open fields and greenhouses. Bottle gourd plants (Lagenaria siceraria) are being used throughout the world as rootstocks for grafting watermelon. In recent years, there has been a growing interest in the USA in...

  2. Characterization of resistance mechanisms to powdery mildew (Erysiphe betae) in beet (Beta vulgaris).

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Prats, Elena; Emeran, Amero A; Rubiales, Diego

    2009-04-01

    Beet powdery mildew incited by Erysiphe betae is a serious foliar fungal disease of worldwide distribution causing losses of up to 30%. In the present work, we searched for resistance in a germplasm collection of 184 genotypes of Beta vulgaris including fodder (51 genotypes), garden (60 genotypes), leaf (51 genotypes), and sugar (22 genotypes) beet types. Resistant genotypes were identified in the four beet types under study. In addition, mechanisms underlying resistance were dissected through histological studies. These revealed different resistance mechanisms acting at different fungal developmental stages, i.e., penetration resistance, early and late cell death, or posthaustorial resistance. Most genotypes were able to hamper fungal development at several stages. The later are interesting for breeding aiming to resistance durability. Furthermore, characterization of defense mechanisms will be useful for further cellular and molecular studies to unravel the bases of resistance in this species.

  3. The enhanced callose deposition in barley with ml-o powdery mildew resistance genes

    DEFF Research Database (Denmark)

    Skou, Jens-Peder

    1985-01-01

    Carborundum treatment of barley leaves induced a callose deposition which was detected as diffuse blotches in the epidermal cells of susceptible barleys and as deeply stained tracks along the scratches in barleys with the ml-o powdery mildew resistance gene. Subsequent inoculation with powdery...... mildew resulted in appositions that enlarged inversely to their size in the respective varieties when inoculated without carborundum treatment. Aphids sucking the leaves resulted in rows of callose containing spots along the anticlinal cell walls. The spots were larger in the ml-o mutant than...... in the mother variety. Callose was deposited in connection with the pleiotropic necrotic spotting in barleys with the ml-o gene. Modification of the necrotic spotting by crossing the ml-o gene into other gene backgrounds did not result in any change in the size of appositions upon inoculation with powdery...

  4. The enhanced callose deposition in barley with ml-o powdery mildew resistance genes

    DEFF Research Database (Denmark)

    Skou, Jens-Peder

    1985-01-01

    Carborundum treatment of barley leaves induced a callose deposition which was detected as diffuse blotches in the epidermal cells of susceptible barleys and as deeply stained tracks along the scratches in barleys with the ml-o powdery mildew resistance gene. Subsequent inoculation with powdery...... mildew resulted in appositions that enlarged inversely to their size in the respective varieties when inoculated without carborundum treatment. Aphids sucking the leaves resulted in rows of callose containing spots along the anticlinal cell walls. The spots were larger in the ml-o mutant than...... in the mother variety. Callose was deposited in connection with the pleiotropic necrotic spotting in barleys with the ml-o gene. Modification of the necrotic spotting by crossing the ml-o gene into other gene backgrounds did not result in any change in the size of appositions upon inoculation with powdery...

  5. Assessment of Lipid Transfer Protein (LTP1) Gene in Wheat Powdery Mildew Resistance

    Institute of Scientific and Technical Information of China (English)

    LI Ai-li; MENG Cheng-sheng; ZHOU Rong-hua; MA Zhi-ying; JIA Ji-zeng

    2006-01-01

    This study is to investigate the role of lipid transfer protein (LTP1) gene of wheat (Triticum aestivum L.) in powdery mildew (Blumeria graminis f. sp. tritici, Bgt) resistance. A pair of primers based on the full length cDNA of wheat LTP1was used for amplifying the coding regions of LTP in hexaploid (AABBDD) wheat and its diploid donors T. urartu (AA),Ae. speltoides ssp speltoide (SS) and Ae. tauchii ssp strangulate (DD). LTP1 and LTP2 of wheat were isolated from the tested two hexaploid (ABD) materials: powdery mildew resistance near isogenic line (NIL) Mardler/7 x B ainong 3217 and its susceptible parent Bainong 3217 at the same time, while only one kind of LTP gene was found in the tested three diploid materials respectively by using the above PCR primer pairs. Two peaks of the expression of LTP1 and LTP2 induced by powdery mildew were observed [one occurred at 3 h after inoculation (hai); the other occurred at 10 hai] in resistant NIL Mardler/7 x Bainong3217 in comparison with a steady transcript level of LTP1 and LTP2 in susceptible Bainong3217.Transient over-expression result showed that LTP1 reduced the penetration efficiency (PE) of powdery mildew in susceptible cultivar by about 28.3%. This result indicated an obvious effectiveness of LTP1 in powdery mildew resistance. Expression analysis also showed that LTP1 and LTP2 of wheat are generally involved in salt/drought, but not in low temperature stress early responses.

  6. Elevated early callose deposition results in complete penetration resistance to powdery mildew in Arabidopsis.

    Science.gov (United States)

    Ellinger, Dorothea; Naumann, Marcel; Falter, Christian; Zwikowics, Claudia; Jamrow, Torsten; Manisseri, Chithra; Somerville, Shauna C; Voigt, Christian A

    2013-03-01

    A common response by plants to fungal attack is deposition of callose, a (1,3)-β-glucan polymer, in the form of cell wall thickenings called papillae, at site of wall penetration. While it has been generally believed that the papillae provide a structural barrier to slow fungal penetration, this idea has been challenged in recent studies of Arabidopsis (Arabidopsis thaliana), where fungal resistance was found to be independent of callose deposition. To the contrary, we show that callose can strongly support penetration resistance when deposited in elevated amounts at early time points of infection. We generated transgenic Arabidopsis lines that express POWDERY MILDEW RESISTANT4 (PMR4), which encodes a stress-induced callose synthase, under the control of the constitutive 35S promoter. In these lines, we detected callose synthase activity that was four times higher than that in wild-type plants 6 h post inoculation with the virulent powdery mildew Golovinomyces cichoracearum. The callose synthase activity was correlated with enlarged callose deposits and the focal accumulation of green fluorescent protein-tagged PMR4 at sites of attempted fungal penetration. We observed similar results from infection studies with the nonadapted powdery mildew Blumeria graminis f. sp. hordei. Haustoria formation was prevented in resistant transgenic lines during both types of powdery mildew infection, and neither the salicylic acid-dependent nor jasmonate-dependent pathways were induced. We present a schematic model that highlights the differences in callose deposition between the resistant transgenic lines and the susceptible wild-type plants during compatible and incompatible interactions between Arabidopsis and powdery mildew.

  7. Mapping of Mungbean Yellow Mosaic India Virus (MYMIV and powdery mildew resistant gene in black gram [Vigna mungo(L. Hepper

    Directory of Open Access Journals (Sweden)

    Tuba Anjum,K. Sanjeev Gupta and Subhojit Datta

    2010-07-01

    Full Text Available Black gram, one of the important species of Asian Vigna group of grain legumes, is widely grown in South Asia and is animportant source of dietary protein. The two main biological constraints particularly Mungbean Yellow Mosaic IndiaVirus(MYMIV and powdery mildew pose a major threat to black gram production in India. Several reports on mappingmungbean yellow mosaic virus disease and powdery mildew resistant genes on black gram using parental lines suitable forcountries viz. Australia and Japan are available. However, to achieve precision in plant breeding, it is important that mappingof traits are done using parental lines which are best suited for the target area/country. Microsatellite markers facilitateeffective screening of mapping population and marker assisted selection for target traits such as disease resistance in manycrops. Linkage mapping for identification of genes conferring resistance to these target traits in the crop is underway. Theparents selected for MYMIV mapping population are DPU 88-31 as resistant source and AKU 9904 as susceptible one. Forestablishment of powdery mildew mapping population RBU 38 was used as resistant and DPU 88-31 as the susceptible one.Parental polymorphism was assessed using 363 SSR and 24 RGH markers. Efforts are being made to identify the markerstightly linked to the genes responsible for resistance which will be useful for marker assisted breeding for developingMYMIV and powdery mildew resistant cultivars in black gram.

  8. QTL mapping of powdery mildew resistance in WI 2757 cucumber (Cucumis sativus L.).

    Science.gov (United States)

    He, Xiaoming; Li, Yuhong; Pandey, Sudhakar; Yandell, Brain S; Pathak, Mamta; Weng, Yiqun

    2013-08-01

    Powdery mildew (PM) is a very important disease of cucumber (Cucumis sativus L.). Resistant cultivars have been deployed in production for a long time, but the genetic mechanisms of PM resistance in cucumber are not well understood. A 3-year QTL mapping study of PM resistance was conducted with 132 F2:3 families derived from two cucumber inbred lines WI 2757 (resistant) and True Lemon (susceptible). A genetic map covering 610.4 cM in seven linkage groups was developed with 240 SSR marker loci. Multiple QTL mapping analysis of molecular marker data and disease index of the hypocotyl, cotyledon and true leaf for responses to PM inoculation identified six genomic regions in four chromosomes harboring QTL for PM resistance in WI 2757. Among the six QTL, pm1.1 and pm1.2 in chromosome 1 conferred leaf resistance. Minor QTL pm3.1 (chromosome 3) and pm4.1 (chromosome 4) contributed to disease susceptibility. The two major QTL, pm5.1 and pm5.2 were located in an interval of ~40 cM in chromosome 5 with each explaining 21.0-74.5 % phenotypic variations. Data presented herein support two recessively inherited, linked major QTL in chromosome 5 plus minor QTL in other chromosomes that control the PM resistance in WI 2757. The QTL pm5.2 for hypocotyl resistance plays the most important role in host resistance. Multiple observations in the same year revealed the importance of scoring time in the detection of PM resistance QTL. Results of this study provided new insights into phenotypic and genetic mechanisms of powdery mildew resistance in cucumber.

  9. Identification and utilization of a new Erysiphe necator isolate NAFU1 to quickly evaluate powdery mildew resistance in wild Chinese grapevine species using detached leaves.

    Science.gov (United States)

    Gao, Yu-Rong; Han, Yong-Tao; Zhao, Feng-Li; Li, Ya-Juan; Cheng, Yuan; Ding, Qin; Wang, Yue-Jin; Wen, Ying-Qiang

    2016-01-01

    The most economically important disease of cultivated grapevines worldwide is powdery mildew caused by the biotrophic fungal pathogen Erysiphe necator. To integrate effective genetic resistance into cultivated grapevines, numerous disease resistance screens of diverse Vitis germplasm, including wild species, have been conducted to identify powdery mildew resistance, but the results have been inconsistent. Here, a new powdery mildew isolate that is infectious on grapevines, designated Erysiphe necator NAFU1 (En. NAFU1), was identified and characterized by phylogeny inferred from the internal transcribed spacer (ITS) of pathogen ribosomal DNA sequences. Three classical methods were compared for the maintenance of En. NAFU1, and the most convenient method was maintenance on detached leaves and propagation by contact with infected leaves. Furthermore, controlled inoculations of En. NAFU1 were performed using detached leaves from 57 wild Chinese grapevine accessions to quickly evaluate powdery mildew resistance based on trypan blue staining of leaf sections. The results were compared with previous natural epidemics in the field. Among the screened accessions inoculated with En. NAFU1, 22.8% were resistant, 33.3% were moderately resistant, and 43.9% were susceptible. None of the accessions assessed herein were immune from infection. These results support previous findings documenting the presence of race-specific resistance to E. necator in wild Chinese grapevine. The resistance of wild Chinese grapevine to En. NAFU1 could be due to programmed cell death. The present results suggest that En. NAFU1 isolate could be used for future large-scale screens of resistance to powdery mildew in diverse Vitis germplasms and investigations of the interaction between grapevines and pathogens.

  10. Identification and Mapping of Two New Genes Conferring Resistance to Powdery Mildew from Aegilops tauschii (Coss.) Schmal

    Institute of Scientific and Technical Information of China (English)

    Xiao-Li Sun; Di Liu; Hai-Quan Zhang; Na-Xin Huo; Rong-Hua Zhou; Ji-Zeng Jia

    2006-01-01

    Two powdery mildew resistance genes were Identified from Aegilops tauschii accessions Y201 and Y212and mapped using two different F2 populations derived from the crosses between susceptible accession Y2272 and Y201, and susceptible accession Y2263 and Y212. Genetic analysis of resistance to powdery mildew indicated that the resistance of Y201 was controlled by a single dominant gene, whereas the resistance of Y212 was controlled by a single recessive gene. We have temporarily designated these genes as PmY201 and PmY212, respectively. By bulk segregation analysis, six microsatellite markers including Xgwm174, cfd26, cfd57, cfd102, Xgwm583 and Xgwm639 were found to be linked to PmY201 with genetic distances of 5.2, 7.7, 9.6, 12.5, 20.2 and 22.1 cM, respectively. Five SSR markers, including cfd57, Xgwm182,cfd7, cfd102, and cfd12, were found to be linked to PmY212 with distances of 5.6, 7.2, 11.5, 14.7, and 18.5 cM,respectively. According to the locations of the linked markers, the two resistance genes were located in the 5DL region. Based on the chromosomal locations and the resistance patterns of the two genes, we propose that PmY201 and PmY212 are two novel powdery mildew resistance genes, and are suitable for marker-assisted selection.

  11. Towards positional isolation of three quantitative trait loci conferring resistance to powdery mildew in two Spanish barley landraces.

    Directory of Open Access Journals (Sweden)

    Cristina Silvar

    Full Text Available Three quantitative trait loci (QTL conferring broad spectrum resistance to powdery mildew, caused by the fungus Blumeria graminis f. sp. hordei, were previously identified on chromosomes 7HS, 7HL and 6HL in the Spanish barley landrace-derived lines SBCC097 and SBCC145. In the present work, a genome-wide putative linear gene index of barley (Genome Zipper and the first draft of the physical, genetic and functional sequence of the barley genome were used to go one step further in the shortening and explicit demarcation on the barley genome of these regions conferring resistance to powdery mildew as well as in the identification of candidate genes. First, a comparative analysis of the target regions to the barley Genome Zippers of chromosomes 7H and 6H allowed the development of 25 new gene-based molecular markers, which slightly better delimit the QTL intervals. These new markers provided the framework for anchoring of genetic and physical maps, figuring out the outline of the barley genome at the target regions in SBCC097 and SBCC145. The outermost flanking markers of QTLs on 7HS, 7HL and 6HL defined a physical area of 4 Mb, 3.7 Mb and 3.2 Mb, respectively. In total, 21, 10 and 16 genes on 7HS, 7HL and 6HL, respectively, could be interpreted as potential candidates to explain the resistance to powdery mildew, as they encode proteins of related functions with respect to the known pathogen defense-related processes. The majority of these were annotated as belonging to the NBS-LRR class or protein kinase family.

  12. Differential gene expression in individual papilla-resistant and powdery mildew-infected barley epidermal cells

    DEFF Research Database (Denmark)

    Gjetting, T.; Carver, Timothy L. W.; Skøt, Leif

    2004-01-01

    Resistance and susceptibility in barley to the powdery mildew fungus (Blumeria graminis f. sp. hordei) is determined at the single-cell level. Even in genetically compatible interactions, attacked plant epidermal cells defend themselves against attempted fungal penetration by localized responses...... leading to papilla deposition and reinforcement of their cell wall. This conveys a race-nonspecific form of resistance. However, this defense is not complete, and a proportion of penetration attempts succeed in infection. The resultant mixture of infected and uninfected leaf cells makes it impossible...... to relate powdery mildew-induced gene expression in whole leaves or even dissected epidermal tissues to resistance or susceptibility. A method for generating transcript profiles from individual barley epidermal cells was established and proven useful for analyzing resistant and successfully infected cells...

  13. Inheritance of resistance to powdery mildew in pea and pathogenesis-related aspects

    Directory of Open Access Journals (Sweden)

    Ricardo Lima dos Santos

    2012-06-01

    Full Text Available The inheritance of resistance to powdery mildew in the pea cultivar MK-10 and some histological aspects of infection were assessed. For the inheritance study, F1, F2, backcrosses and F3 generations of MK-10 crossed with two susceptible populations were evaluated. Histological evaluations included percentage of germinated conidia, percentage of conidia that formed appresoria, percentage of conidia that established colonies, and number of haustoria per colony. Segregation ratios obtained in the resistance inheritance study were compared by Chi-square (ײ test and the histological data were analyzed by Tukey's test at 5% probability. It was concluded that resistance of MK-10 to powdery mildew is due to a pair of recessive alleles since it is expressed in the pre-penetration stage and completed by post-penetration localized cellular death, characteristic of the presence of the pair of recessive alleles er1er1.

  14. The value of powdery mildew resistance in grapes: Evidence from California

    Directory of Open Access Journals (Sweden)

    Kate Binzen Fuller

    2014-12-01

    Full Text Available Powdery mildew (PM is a fungal disease that damages many crops, including grapes. In California, wine, raisin, and table grapes contributed over $3.9 billion to the value of farm production in 2011. Grape varieties with resistance to powdery mildew are currently being developed, using either conventional or transgenic approaches, each of which has associated advantages and disadvantages. PM-resistant varieties of grapes could yield large economic benefits to California grape growers—potentially allowing cost savings as high as $48 million per year in the subset of the industry covered by our analysis (Crimson Seedless table grapes, all raisin grapes, and Central Coast Chardonnay wine grapes, but benefits range widely across the different grape production systems.

  15. Inhibitive Mechanisms of Two Silicon Compounds on Powdery Mildew of Melon

    Institute of Scientific and Technical Information of China (English)

    GUO Yu-rong; LIU Lei; ZHAO Hua; CHEN De-rong; BI Yang

    2005-01-01

    Seedlings of Yujinxiang melon were used to investigate the effect and inhibitive mechanism of sodium silicate and nanosized silicon oxide on powdery mildew. The results showed that the severity of powdery mildew on melon seedlings was lowered significantly by treatment with either of the two silicon compounds, although the effect of sodium silicate was more powerful than silicon oxide. Application of sodium silicate to the seedlings caused significant increases in the activity of peroxidase (POD) and of 3-1,3-glucosidase (GLU), both enzymes are known to be associated with the disease defence systems of plants. SEM-EDX analysis of sodium silicate-treated leaves of the melon seedlings showed an elevated level of silicon deposit at stomata and epidermis. Treatment with nanosized silicon oxide also resulted in a similar increase in silicon deposit, but the treatment did not cause a significant increase in POD activity.

  16. Arabidopsis phospholipase Dδ is involved in basal defense and nonhost resistance to powdery mildew fungi

    DEFF Research Database (Denmark)

    Pinosa, Francesco; Buhot, Nathalie; Kwaaitaal, Mark Adrianus Cornelis J

    2013-01-01

    Plants have evolved a complex array of defensive responses against pathogenic microorganisms. Recognition of microbes initiates signaling cascades that activate plant defenses. The membrane lipid phosphatidic acid, produced by phospholipase D (PLD), has been shown to take part in both abiotic...... and biotic stress signaling. In this study, the involvement of PLD in the interaction between Arabidopsis (Arabidopsis thaliana) and the barley powdery mildew fungus Blumeria graminis f. sp. hordei (Bgh) was investigated. This nonadapted pathogen is normally resisted by a cell wall-based defense, which stops....... In conclusion, we propose that PLD is involved in defense signaling in nonhost resistance against powdery mildew fungi and put PLDδ forward as the main isoform participating in this process....

  17. A Japanese powdery mildew isolate with exceptionally large infection efficience on Mlo-resistant barley

    DEFF Research Database (Denmark)

    Lyngkjær, M.F.; Jensen, H.P.; Østergård, Hanne

    1995-01-01

    A Japanese field isolate (Race I) of Erysiphe graminis f,sp. hordei was tested on 17 barley lines carrying the mlo powdery mildew resistance gene. Race I produced many successful infections with infection type larger than or equal to 2 on six lines (M66, MC20, SR1, SR7, Atem and Totem). On the re......A Japanese field isolate (Race I) of Erysiphe graminis f,sp. hordei was tested on 17 barley lines carrying the mlo powdery mildew resistance gene. Race I produced many successful infections with infection type larger than or equal to 2 on six lines (M66, MC20, SR1, SR7, Atem and Totem...

  18. Hot pepper (Capsicum chinense, Jacq. inheritance of reaction to powdery mildew

    Directory of Open Access Journals (Sweden)

    Blat Sally Ferreira

    2006-01-01

    Full Text Available The pepper species C. chinense has been considered one of the most important resistance sources to powdery mildew Capsicum spp. However, the inheritance in this species was unknown. The purpose of this work was to study its reaction inheritance. Two powdery mildew resistant parents, 'Pimenta Cheiro' 1 and PI 152225 and two moderately susceptible ones, 'Pimenta Doce' IH-1761 and 'Pimenta Índio', were used to obtain three F1 and their respective F2 generations: 'Pimenta Doce' IH-1761 'Pimenta Cheiro' 1, 'Pimenta Índio' PI 152225 and 'Pimenta Doce' IH-1761 PI 152225. The powdery mildew epidemy was natural using inoculum from a highly-sporulating susceptible pepper host. Powdery mildew host reaction evaluations were carried out during the fruiting stage using a rating system based on disease severity scales varying from 1 (resistant to 5 (highly susceptible. The experimental design was completely randomized. The following genetic parameters were estimated: gene action, heritability coefficient and expected selection gain in the F3 generation. The transgressive segregation in F2 indicated oligogenic inheritance. Results show the presence of additive, dominant, and epistatic gene action. The dominant and epistatic effects detected in crosses presented negative values, tending towards susceptibility. The heritability and selection gain estimates were moderate, with values of 35.5% and 1.7% for 'Pimenta Doce' IH 1761 'Pimenta Cheiro' 1, from 50.4% to 3.5% for 'Pimenta Índio' PI 152225, and 49% and 2.7% for the 'Pimenta Doce' IH 1761 PI 152225 crosses, respectively. These gene action results are favorable for breeding programs and exploration of hybrids.

  19. Multiple Evolutionary Events Involved in Maintaining Homologs of Resistance to Powdery Mildew 8 in Brassica napus

    Science.gov (United States)

    Li, Qin; Li, Jing; Sun, Jin-Long; Ma, Xian-Feng; Wang, Ting-Ting; Berkey, Robert; Yang, Hui; Niu, Ying-Ze; Fan, Jing; Li, Yan; Xiao, Shunyuan; Wang, Wen-Ming

    2016-01-01

    The Resistance to Powdery Mildew 8 (RPW8) locus confers broad-spectrum resistance to powdery mildew in Arabidopsis thaliana. There are four Homologous to RPW8s (BrHRs) in Brassica rapa and three in Brassica oleracea (BoHRs). Brassica napus (Bn) is derived from diploidization of a hybrid between B. rapa and B. oleracea, thus should have seven homologs of RPW8 (BnHRs). It is unclear whether these genes are still maintained or lost in B. napus after diploidization and how they might have been evolved. Here, we reported the identification and sequence polymorphisms of BnHRs from a set of B. napus accessions. Our data indicated that while the BoHR copy from B. oleracea is highly conserved, the BrHR copy from B. rapa is relatively variable in the B. napus genome owing to multiple evolutionary events, such as gene loss, point mutation, insertion, deletion, and intragenic recombination. Given the overall high sequence homology of BnHR genes, it is not surprising that both intragenic recombination between two orthologs and two paralogs were detected in B. napus, which may explain the loss of BoHR genes in some B. napus accessions. When ectopically expressed in Arabidopsis, a C-terminally truncated version of BnHRa and BnHRb, as well as the full length BnHRd fused with YFP at their C-termini could trigger cell death in the absence of pathogens and enhanced resistance to powdery mildew disease. Moreover, subcellular localization analysis showed that both BnHRa-YFP and BnHRb-YFP were mainly localized to the extra-haustorial membrane encasing the haustorium of powdery mildew. Taken together, our data suggest that the duplicated BnHR genes might have been subjected to differential selection and at least some may play a role in defense and could serve as resistance resource in engineering disease-resistant plants. PMID:27493652

  20. Multiple Evolutionary Events Involved in Maintaining Homologs of Resistance to Powdery Mildew 8 in Brassica napus.

    Science.gov (United States)

    Li, Qin; Li, Jing; Sun, Jin-Long; Ma, Xian-Feng; Wang, Ting-Ting; Berkey, Robert; Yang, Hui; Niu, Ying-Ze; Fan, Jing; Li, Yan; Xiao, Shunyuan; Wang, Wen-Ming

    2016-01-01

    The Resistance to Powdery Mildew 8 (RPW8) locus confers broad-spectrum resistance to powdery mildew in Arabidopsis thaliana. There are four Homologous to RPW8s (BrHRs) in Brassica rapa and three in Brassica oleracea (BoHRs). Brassica napus (Bn) is derived from diploidization of a hybrid between B. rapa and B. oleracea, thus should have seven homologs of RPW8 (BnHRs). It is unclear whether these genes are still maintained or lost in B. napus after diploidization and how they might have been evolved. Here, we reported the identification and sequence polymorphisms of BnHRs from a set of B. napus accessions. Our data indicated that while the BoHR copy from B. oleracea is highly conserved, the BrHR copy from B. rapa is relatively variable in the B. napus genome owing to multiple evolutionary events, such as gene loss, point mutation, insertion, deletion, and intragenic recombination. Given the overall high sequence homology of BnHR genes, it is not surprising that both intragenic recombination between two orthologs and two paralogs were detected in B. napus, which may explain the loss of BoHR genes in some B. napus accessions. When ectopically expressed in Arabidopsis, a C-terminally truncated version of BnHRa and BnHRb, as well as the full length BnHRd fused with YFP at their C-termini could trigger cell death in the absence of pathogens and enhanced resistance to powdery mildew disease. Moreover, subcellular localization analysis showed that both BnHRa-YFP and BnHRb-YFP were mainly localized to the extra-haustorial membrane encasing the haustorium of powdery mildew. Taken together, our data suggest that the duplicated BnHR genes might have been subjected to differential selection and at least some may play a role in defense and could serve as resistance resource in engineering disease-resistant plants.

  1. Development of partial ontogenic resistance to powdery mildew in hop cones and its management implications.

    Science.gov (United States)

    Twomey, Megan C; Wolfenbarger, Sierra N; Woods, Joanna L; Gent, David H

    2015-01-01

    Knowledge of processes leading to crop damage is central to devising rational approaches to disease management. Multiple experiments established that infection of hop cones by Podosphaera macularis was most severe if inoculation occurred within 15 to 21 days after bloom. This period of infection was associated with the most pronounced reductions in alpha acids, cone color, and accelerated maturation of cones. Susceptibility of cones to powdery mildew decreased progressively after the transition from bloom to cone development, although complete immunity to the disease failed to develop. Maturation of cone tissues was associated with multiple significant affects on the pathogen manifested as reduced germination of conidia, diminished frequency of penetration of bracts, lengthening of the latent period, and decreased sporulation. Cones challenged with P. macularis in juvenile developmental stages also led to greater frequency of colonization by a complex of saprophytic, secondary fungi. Since no developmental stage of cones was immune to powdery mildew, the incidence of powdery mildew continued to increase over time and exceeded 86% by late summer. In field experiments with a moderately susceptible cultivar, the incidence of cones with powdery mildew was statistically similar when fungicide applications were made season-long or targeted only to the juvenile stages of cone development. These studies establish that partial ontogenic resistance develops in hop cones and may influence multiple phases of the infection process and pathogen reproduction. The results further reinforce the concept that the efficacy of a fungicide program may depend largely on timing of a small number of sprays during a relatively brief period of cone development. However in practice, targeting fungicide and other management tactics to periods of enhanced juvenile susceptibility may be complicated by a high degree of asynchrony in cone development and other factors that are situation-dependent.

  2. Management of Powdery Mildew in Squash by Plant and Alga Extract Biopesticides

    Directory of Open Access Journals (Sweden)

    Shouan Zhang

    2016-12-01

    Full Text Available Although many fungicides are registered for use to control powdery mildew on cucurbits, management of resistance to fungicides in pathogen populations still remains a major challenge. Two biopesticides Regalia SC and HMO 736 were evaluated in the greenhouse and field for their efficacy against powdery mildew in squash. In greenhouses, Regalia SC alone significantly (P < 0.05 reduced powdery mildew compared to the nontreated control, and was as effective as the chemical standard Procure 480SC (triflumizole. In alternation with Procure 480SC, Regalia SC demonstrated greater or equivalent effects on reducing the disease. HMO 736 alone showed varying levels of disease control, but alternating with Procure 480SC significantly improved control efficacy. In addition, application of Regalia SC or HMO 736 each in alternation with Procure 480SC significantly increased the chlorophyll content in leaves and the total fresh weight of squash plants, when compared with the water control, Regalia SC and HMO 736 alone. In field trials, application of Regalia SC and HMO 736 each alone significantly reduced disease severity in one of two field trials during the early stage of disease development, but not during later stages when disease pressure became high. Both Regalia SC and HMO 736 each applied in alternation with Procure 480SC significantly improved the control efficacy compared to Procure 480SC alone. Results from this study demonstrated that an integrated management program can be developed for powdery mildew in squash by integrating the biopesticides Regalia SC, HMO 736 with the chemical fungicide Procure 480SC.

  3. Development of partial ontogenic resistance to powdery mildew in hop cones and its management implications.

    Directory of Open Access Journals (Sweden)

    Megan C Twomey

    Full Text Available Knowledge of processes leading to crop damage is central to devising rational approaches to disease management. Multiple experiments established that infection of hop cones by Podosphaera macularis was most severe if inoculation occurred within 15 to 21 days after bloom. This period of infection was associated with the most pronounced reductions in alpha acids, cone color, and accelerated maturation of cones. Susceptibility of cones to powdery mildew decreased progressively after the transition from bloom to cone development, although complete immunity to the disease failed to develop. Maturation of cone tissues was associated with multiple significant affects on the pathogen manifested as reduced germination of conidia, diminished frequency of penetration of bracts, lengthening of the latent period, and decreased sporulation. Cones challenged with P. macularis in juvenile developmental stages also led to greater frequency of colonization by a complex of saprophytic, secondary fungi. Since no developmental stage of cones was immune to powdery mildew, the incidence of powdery mildew continued to increase over time and exceeded 86% by late summer. In field experiments with a moderately susceptible cultivar, the incidence of cones with powdery mildew was statistically similar when fungicide applications were made season-long or targeted only to the juvenile stages of cone development. These studies establish that partial ontogenic resistance develops in hop cones and may influence multiple phases of the infection process and pathogen reproduction. The results further reinforce the concept that the efficacy of a fungicide program may depend largely on timing of a small number of sprays during a relatively brief period of cone development. However in practice, targeting fungicide and other management tactics to periods of enhanced juvenile susceptibility may be complicated by a high degree of asynchrony in cone development and other factors that are

  4. Effects of bunch rot (Botrytis cinerea) and powdery mildew (Erysiphe necator) fungal diseases on wine aroma

    Science.gov (United States)

    Lopez Pinar, Angela; Rauhut, Doris; Ruehl, Ernst; Buettner, Andrea

    2017-03-01

    This study aimed to characterize the effects of bunch rot and powdery mildew on the primary quality parameter of wine, the aroma. The influence of these fungal diseases was studied by comparative Aroma Extract Dilution Analyses (AEDA) and sensory tests. The effect of bunch rot was investigated on three grape varieties, namely White Riesling, Red Riesling and Gewürztraminer and that of powdery mildew on the hybrid Gm 8622-3; thereby, samples were selected that showed pronounced cases of infection to elaborate potential currently unknown effects. Both infections revealed aromatic differences induced by these fungi. The sensory changes were not associated with one specific compound only, but were due to quantitative variations of diverse substances. Bunch rot predominantly induced an increase in the intensities of peach-like/fruity, floral and liquor-like/toasty aroma notes. These effects were found to be related to variations in aroma substance composition as monitored via AEDA, mainly an increase in the FD factors of lactones and a general moderate increase of esters and alcohols. On the other hand, powdery mildew decreased the vanilla-like character of the wine while the remaining sensory attributes were rather unaffected. Correspondingly, FD factors of the main aroma constituents were either the same or only slightly modified by this disease. Moreover, bunch rot influenced the aroma profiles of the three varieties studied to a different degree. In hedonic evaluation, bunch rot-affected samples were rated as being more pleasant in comparison to their healthy controls in all three varieties while the powdery mildew-affected sample was rated as being less pleasant than its healthy control.

  5. Wheat protection against powdery mildew by arbuscular mycorrhizal fungi : mechanisms and optimization

    OpenAIRE

    Mustafa, Ghalia

    2015-01-01

    The use of arbuscular mycorrhizal fungi (AMF) could be an innovative alternative to chemicals against fungal plant diseases. Our work aimed at studying the possible protective effect of arbuscular mycorrhization in the bread wheat (Triticum aestivum L.) against Blumeria graminis f. sp. tritici (Bgt), a biotrophic fungi responsible of wheat powdery mildew, a disease affecting the aerial plant organs. Wheat mycorrhizal inoculation by Funneliformis mosseae (Fm), under controlled and optimized co...

  6. Multiple evolutionary events involved in maintaining homologs of Resistance to Powdery Mildew 8 in Brassica napus

    Directory of Open Access Journals (Sweden)

    Qin Li

    2016-07-01

    Full Text Available The Resistance to Powdery Mildew 8 (RPW8 locus confers broad-spectrum resistance to powdery mildew in Arabidopsis thaliana. There are four Homologous to RPW8s (BrHRs in Brassica rapa and three in B. oleracea (BoHRs. B. napus (Bn is derived from diploidization of a hybrid between B. rapa and B. oleracea, thus should have seven homologs of RPW8 (BnHRs. It is unclear whether these genes are still maintained or lost in B. napus after diploidization and how they might have been evolved. Here we reported the identification and sequence polymorphisms of BnHRs from a set of B. napus accessions. Our data indicated that while the BoHR copy from B. oleracea is highly conserved, the BrHR copy from B. rapa is relatively variable in the B. napus genome owing to multiple evolutionary events, such as gene loss, point mutation, insertion, deletion and intragenic recombination. Given the overall high sequence homology of BnHR genes, it is not surprising that both intragenic recombination between two orthologs and two paralogs were detected in B. napus, which may explain the loss of BoHR genes in some B. napus accessions. When ectopically expressed in Arabidopsis, a C-terminally truncated version of BnHRa and BnHRb, as well as the full length BnHRd fused with YFP at their C-termini could trigger cell death in the absence of pathogens and enhanced resistance to powdery mildew disease. Moreover, subcellular localization analysis showed that both BnHRa-YFP and BnHRb-YFP were mainly localized to the extra-haustorial membrane (EHM encasing the haustorium of powdery mildew. Taken together, our data suggest that the duplicated BnHR genes might have been subjected to differential selection and at least some may play a role in defense and could serve as resistance resource in engineering disease-resistant plants.

  7. Airborne hyperspectral imaging for the detection of powdery mildew in wheat

    Science.gov (United States)

    Franke, Jonas; Mewes, Thorsten; Menz, Gunter

    2008-08-01

    Plant stresses, in particular fungal diseases, show a high variability in spatial and temporal dimension with respect to their impact on the host. Recent "Precision Agriculture"-techniques allow for a spatially and temporally adjusted pest control that might reduce the amount of cost-intensive and ecologically harmful agrochemicals. Conventional stressdetection techniques such as random monitoring do not meet demands of such optimally placed management actions. The prerequisite is an accurate sensor-based detection of stress symptoms. The present study focuses on a remotely sensed detection of the fungal disease powdery mildew (Blumeria graminis) in wheat, Europe's main crop. In a field experiment, the potential of hyperspectral data for an early detection of stress symptoms was tested. A sophisticated endmember selection procedure was used and, additionally, a linear spectral mixture model was applied to a pixel spectrum with known characteristics, in order to derive an endmember representing 100% powdery mildew-infected wheat. Regression analyses of matched fraction estimates of this endmember and in-field-observed powdery mildew severities showed promising results (r=0.82 and r2=0.67).

  8. Breeding and molecular cytogenetic identification of wheat-Thinopyrum intermedium addition lines resistant to powdery mildew

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Wheat-related species Th. intermedium was used to cross with common wheat Yannong 15. In the self progenies of the hybrid, two addition lines, Ⅱ-1-7-1 and Ⅱ-3-3-2, stable in cytology, were developed by cytology and powdery mildew resistance identification. Their chromosome number were 2n = 44 and formed 22 bivalents at PMC MI. In F1 of the two addition lines crossing with Yannong 15, there appeared about one univalent at PMC MI, respectively. Resistance identification in greenhouse and field using the No. 15 and mixed strains of E. gramnis f. sp. tritici showed that they were immune to powdery mildew. Chromosome number and resistance identification using the F2 single plants of the addition line crossing with Yannong 15 indicated that the resistant gene was located on the alien chromosomes. In situ hybridization using St and E genomic DNA as probe showed that the added chromosome in the two addition lines probably came from the E genome of Th. intermedium, which indicated that a pair of E genome chromosomes carried a new resistant gene to powdery mildew.

  9. Transformation of the cucurbit powdery mildew pathogen Podosphaera xanthii by Agrobacterium tumefaciens.

    Science.gov (United States)

    Martínez-Cruz, Jesús; Romero, Diego; de Vicente, Antonio; Pérez-García, Alejandro

    2017-03-01

    The obligate biotrophic fungal pathogen Podosphaera xanthii is the main causal agent of powdery mildew in cucurbit crops all over the world. A major limitation of molecular studies of powdery mildew fungi (Erysiphales) is their genetic intractability. In this work, we describe a robust method based on the promiscuous transformation ability of Agrobacterium tumefaciens for reliable transformation of P. xanthii. The A. tumefaciens-mediated transformation (ATMT) system yielded transformants of P. xanthii with diverse transferred DNA (T-DNA) constructs. Analysis of the resultant transformants showed the random integration of T-DNA into the P. xanthii genome. The integrations were maintained in successive generations in the presence of selection pressure. Transformation was found to be transient, because in the absence of selection agent, the introduced genetic markers were lost due to excision of T-DNA from the genome. The ATMT system represents a potent tool for genetic manipulation of P. xanthii and will likely be useful for studying other biotrophic fungi. We hope that this method will contribute to the development of detailed molecular studies of the intimate interaction established between powdery mildew fungi and their host plants.

  10. Effects of silicates from scaps of photovoltaic industries on powdery mildew of zucchini.

    Science.gov (United States)

    Pugliese, M; Alvarez, M T Moreno; Gullino, M L; Garibaldi, A

    2012-01-01

    Silicon is the second most abundant element on earth's surface and its use can stimulate natural defense mechanisms in plants. The effect of silicate from scraps of photovoltaic industries against powdery mildew on zucchini (Cucurbita pepo) was evaluated under greenhouse conditions. Potted plants were inoculated with a spore suspension containing 1 x 10(5) cfu/ml. The following treatments have been carried out, 3 and 10 days after pathogen inoculation: chemical fungicide (propiconazole, TILT 25 EC, Syngenta); Bacillus subtilis (250 g/hl, Serenade, Intrachem); 1% and 0.1% sodium silicate (r = 1); 1% and 0.1% sodium silicate (r = 2); tap water as control. Disease incidence and severity were assessed 7, 14 and 21days after pathogen inoculation. Results showed that the application of 1% sodium silicate (r = 1) significantly reduced the powdery mildew to a level similar to chemical control. The other treatments, including Bacillus subtilis, reduced disease severity compared to water control, but were less efficient. The use of silicates from photovoltaic industries is a valid alternative for the control of powdery mildew on zucchini, in particular in organic farming. However, silicates might not be sufficient at higher disease incidence levels, and their use is more suitable within an integrated disease control strategy.

  11. Effect of climate change on infection of grapevine by downy and powdery mildew under controlled environment.

    Science.gov (United States)

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

    2011-01-01

    Plant responses to elevated CO2 and temperature have been much studied in recent years, but effects of climate change on pathological responses are largerly unknown. The pathosystems grapevine (Vitis vinifera) - downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necatrix) were chosen as models to assess the potential impact of increased CO2 and temperature on disease incidence and severity under controlled environment. Grapevine potted plants were grown in phytotrons under 4 different simulated climatic conditions: (1) standard temperature (ranging from 18 degrees to 22 degrees C) and standard CO2 concentration (450 ppm); (2) standard temperature and elevated CO2 concentration (800 ppm); (3) elevated temperature (ranging from 22 degrees to 26 degrees C, 4 degrees C higher than standard) and standard CO2 concentration; (4) elevated temperature and CO2 concentration. Each plant was inoculated with a spore suspension containing 5x10(5) cfu/ml. Disease index and physiological parameters (chlorophyll content, fluorescence, assimilation rate) were assessed. Results showed an increase of the chlorophyll content with higher temperatures and CO2 concentration, to which consequently corresponded an higher fluorescence index. Disease incidence of downy mildew increased when both CO2 and temperatures were higher, while an increase in CO2 did not influenced powdery mildew incidence, probably due to the increased photosynthetic activity of plants under such conditions. Considering that the rising concentrations of CO2 and other greenhouse gases will lead to an increase in global temperature and longer seasons, we can assume that this will allow more time for pathogens evolution and could increase pathogen survival, indirectly affecting downy and powdery mildews of grapevine.

  12. Effect of soil heating, severity of powdery mildew and nitrogen fertilization on yield of winter wheat

    Energy Technology Data Exchange (ETDEWEB)

    Buschhaus, H.; Werning, L.

    1981-01-01

    Field studies were conducted to determine the effect of different levels of nitrogen and severity of powdery mildew on yield of winter wheat grown in soil heated with waste heat from power plants. Soil heating reduced yield depending on efficiency of mildew control and nitrogen level from 12 to 37%. Disease severity showed a linear increase with intensity of heating corresponding with a decrease in yield reduction. In the non-heated plot, 0.8% of the flag leaves were diseases. Increase soil temperatures by 2-3/sup 0/C caused a 2% rise in mildew severity and at 5-6/sup 0/C 3%, respectively. Control of powdery mildew increased yield on the unheated plot about 5,2 dt/ha, on the moderately heated about 8,7 dt/ha and on the plots with highest temperature about 11,1 dt/ha over that of untreated plots. Nitrogen fertilizers increased yield on non-heated plots, in heated plots with diseased plants, only. Nitrogen did not increases yield of healthy plants on heated plots.

  13. The Novel Gene VpPR4-1 from Vitis pseudoreticulata Increases Powdery Mildew Resistance in Transgenic Vitis vinifera L.

    Science.gov (United States)

    Dai, Lingmin; Wang, Dan; Xie, Xiaoqing; Zhang, Chaohong; Wang, Xiping; Xu, Yan; Wang, Yuejin; Zhang, Jianxia

    2016-01-01

    Pathogenesis-related proteins (PRs) can lead to increased resistance of the whole plant to pathogen attack. Here, we isolate and characterize a PR-4 protein (VpPR4-1) from a wild Chinese grape Vitis pseudoreticulata which shows greatly elevated transcription following powdery mildew infection. Its expression profiles under a number of abiotic stresses were also investigated. Powdery mildew, salicylic acid, and jasmonic acid methyl ester significantly increased the VpPR4-1 induction while NaCl and heat treatments just slightly induced VpPR4-1 expression. Abscisic acid and cold treatment slightly affected the expression level of VpPR4-1. The VpPR4-1 gene was overexpressed in 30 regenerated V. vinifera cv. Red Globe via Agrobacterium tumefaciens-mediated transformation and verified by the Western blot. The 26 transgenic grapevines exhibited higher expression levels of PR-4 protein content than wild-type vines and six of them were inoculated with powdery mildew which showed that the growth of powdery mildew was repressed. The powdery mildew-resistance of Red Globe transformed with VpPR4-1 was enhanced inoculated with powdery mildew. Moreover, other powdery mildew resistant genes were associated with feedback regulation since VpPR4-1 is in abundance. This study demonstrates that PR-4 protein in grapes plays a vital role in defense against powdery mildew invasion.

  14. Powdery mildew outbreaks caused by Podosphaera macularis on Hop cultivars possessing the resistance gene R6 in the Pacific Northwestern United States

    Science.gov (United States)

    Resistant cultivars of hop (Humulus lupulus) have been grown, with the aim of helping to manage powdery mildew in the Pacific Northwest since the first report of the disease in the field in 1997 (4). A major objective of many breeding programs is development of resistance to powdery mildew, and thi...

  15. Dynamic evolution of resistance gene analogs in the orthologous genomic regions of powdery mildew resistance gene MlIW170 in Triticum dicoccoides and Aegilops tauschii

    Science.gov (United States)

    Wheat is one of the most important staple grain crops in the world. Powdery mildew disease caused by Blumeria graminis f.sp. tritici can result in significant losses in both grain yield and quality in wheat. In this study, the wheat powdery mildew resistance gene MlIW170 locus located on the short ...

  16. Identification and genetic mapping of the putative Thinopyrum intermedium-derived dominant powdery mildew resistance gene PmL962 on wheat chromosome arm 2BS

    Science.gov (United States)

    Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease affecting the production of wheat (Triticum aestivum). Powdery mildew resistance was putatively transferred from Thinopyrum intermedium to the common wheat line L962, which conferred resistance to multiple Ch...

  17. Lessons from a Phenotyping Center Revealed by the Genome-Guided Mapping of Powdery Mildew Resistance Loci.

    Science.gov (United States)

    Cadle-Davidson, Lance; Gadoury, David; Fresnedo-Ramírez, Jonathan; Yang, Shanshan; Barba, Paola; Sun, Qi; Demmings, Elizabeth M; Seem, Robert; Schaub, Michelle; Nowogrodzki, Anna; Kasinathan, Hema; Ledbetter, Craig; Reisch, Bruce I

    2016-10-01

    The genomics era brought unprecedented opportunities for genetic analysis of host resistance, but it came with the challenge that accurate and reproducible phenotypes are needed so that genomic results appropriately reflect biology. Phenotyping host resistance by natural infection in the field can produce variable results due to the uncontrolled environment, uneven distribution and genetics of the pathogen, and developmentally regulated resistance among other factors. To address these challenges, we developed highly controlled, standardized methodologies for phenotyping powdery mildew resistance in the context of a phenotyping center, receiving samples of up to 140 grapevine progeny per F1 family. We applied these methodologies to F1 families segregating for REN1- or REN2-mediated resistance and validated that some but not all bioassays identified the REN1 or REN2 locus. A point-intercept method (hyphal transects) to quantify colony density objectively at 8 or 9 days postinoculation proved to be the phenotypic response most reproducibly predicted by these resistance loci. Quantitative trait locus (QTL) mapping with genotyping-by-sequencing maps defined the REN1 and REN2 loci at relatively high resolution. In the reference PN40024 genome under each QTL, nucleotide-binding site-leucine-rich repeat candidate resistance genes were identified-one gene for REN1 and two genes for REN2. The methods described here for centralized resistance phenotyping and high-resolution genetic mapping can inform strategies for breeding resistance to powdery mildews and other pathogens on diverse, highly heterozygous hosts.

  18. Identification of powdery mildew resistance genes in Polish common oat (Avena sativa L. cultivars using host-pathogen tests

    Directory of Open Access Journals (Sweden)

    Sylwia Okoń

    2012-10-01

    Full Text Available The aim of the present study was to characterize and identify powdery mildew resistance genes in Polish common oat cultivars using host-pathogen tests. A differential set of six Blumeria graminis f.sp. avenae isolates virulent or avirulent to four cultivars and one line that has known resistance to powdery mildew were used. Among the investigated cultivars, only four of them (13.3% had resistance patterns similar to genotypes belonging to the differential set. The resistance of OMR group 1 was found in the cultivar ‘Dragon’, while that of OMR2 in the cultivar ‘Skrzat’. The cultivars ‘Deresz’ and ‘Hetman’ showed a resistance pattern that corresponded with OMR group 3. The resistance corresponding to OMR4 was not found, which suggests that until now this gene has not been used in Polish oat breeding programmes. The cultivar ‘Canyon’ had a different pat- tern of resistance than the genotypes that have already known OMR genes, which indicates that the resistance of this cultivar is determined by a new gene or a combination of known genes.

  19. Introgression of Resistance to Powdery Mildew Conferred by Chromosome 2R by Crossing Wheat Nullisomic 2D with Rye

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Using the nullisomic back-cross procedure, four wheat-rye chromosome substitution 2R (2D) lines with different agronomic performance, designated WR02-145-1, WR01-145-2, WR02-145-3, and WR02-145-4, were produced from a cross between 2D nullisomic wheat (Triticum aestivum L. cv. "Xiaoyan 6") and rye (Secale cereale L. cv. "German White"). The chromosomal constitution of 2n=42=21 in WR02-145 lines was confirmed by cytological and molecular cytogenetic methods. Using genomic in situ hybridization on root tip chromosome preparations, a pair of intact rye chromosomes was detected in the WR02-145 lines. PCR using chromosome-specific primers confirmed the presence of 2R chromosomes of rye in these wheat-rye lines, indicating that WR02-145 lines are disomic chromosome substitution lines 2R (2D). The WR02-145 lines are resistant to the powdery mildew (Erysiphe graminis DC. f. sp. tritici E. Marchal) isolates prevalent in northern China and may possess gene(s) for resistance to powdery mildew, which differ from the previously identified Pm7 gene located on chromosome 2RL. The newly developed "Xiaoyan 6"- "German White"2R (2D) chromosome substitution lines are genetically stable, show desirable agronomic traits, and are expected to be useful in wheat improvement.

  20. Quinoa from Valley (Chenopodium quinoa Willd.: Valuable source of genetic resistance to powdery mildew(Peronospora farinosa Willd.

    Directory of Open Access Journals (Sweden)

    Gabriel Julio

    2013-02-01

    Full Text Available In order to identify quinoa resistant cultivars to powdery mildew (Peronospora farinosa of high yield and large grain size, 36 cultivars were evaluated under two different fungicide applications and a control in the Valle Bajo from Cochabamba. We determined the realtive Area under Develop Progress Curve of Peronosporafarinosa (AUDPCPF relative, the yield and another eleven quantitative variables. The results showed that cultivars 01Tardía, 08Tardía, 12Tardía, 04Tardía, 11Tardía 10Tardía, 19Tardía y 18Tardía were susceptible and the cultivars H172, A26, A03, A16, A22, A14 and H171 were resistant. The cultivars A40, H177, A26, H172, A25, A1 y H176 showed yields from 3.4 to 6.34 t ha-1. The cultivars 15 Tardía, 03 Tardía, 14 Tardía, H173, H171, A25, H176 and H172 with chemical control strategy and the tricobalreacted favorably against powdery mildew, which was associated with levels of resistance in each cultivar. Finally, there was a high significant negative correlation between the variables AUDPCPF relative and physiological maturity, plant length, panicle length, stem diameter, panicle diameter and weight of 100 seeds. This showed that when the attack of mildewis severe, also affects the grains yield.

  1. Use of potassium bicarbonate (Armicarb) on the control of powdery mildew (Sphaerotheca mors-uvae) of gooseberry (Ribes uva-crispa).

    Science.gov (United States)

    Wenneker, M; Kanne, J

    2010-01-01

    Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots, stems and fruits of gooseberry (Ribes uva-crispa). Environmental friendly and biological control measures are being sought throughout the world. Especially in organic gooseberry growing effective control measures are needed, because powdery mildew infections may result in a total loss of the crop. In organic currant growing the number of adequate control methods is very limited. Sulphur as a fungicide against powdery mildew in e.g. gooseberry or table grape growing is not recommendable due to possible bleaching of berries and scorching of tender shoots. Various bicarbonate salts are suggested as a good option to control powdery mildew. In a field trial the effect of potassium bicarbonate (Armicarb) on the on the control of powdery mildew of gooseberry was evaluated. Four treatments; i.e. two preventive strategies and two curative strategies, were applied. PLants were sprayed until runoff. The percent of infected fruits and disease severity were assessed. In the unsprayed control plots very high disease incidences were observed; on average more than 90% of the berries were infected with powdery mildew. The weekly (preventive) spray applications with potassium carbonate reduced the disease incidences on fruits significantly. On average approximately 10% of the fruits were affected by powdery mildew. However, the number of spray applications was high. In conclusion, our results indicate that applications of potassium bicarbonate (as Armicarb) are effective in reducing the incidence and severity of American powdery mildew in gooseberry. Early spray applications are necessary to protect berries against powdery mildew infections. Future research will focus on reducing the number of applications, e.g. warning models based on powdery mildew of rose (Sphaerotheca pannosa).

  2. QTL molecular marker location of powdery mildew resistance in cucumber (Cucumis sativus L.)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The cucumber lines, S94 (Northern China open-field type, powdery mildew (PM) susceptible) and S06 (European greenhouse type, PM resistant), and their F6:7 populations were used to investigate PM re-sistance under seedling spray inoculation in 2005/Autumn and 2006/Spring. QTL analysis was under-taken based on a constructed molecular linkage map of the corresponding F6 population using com-posite interval mapping. A total of four QTLs (pm1.1, pm2.1, pm4.1 and pm6.1) for PM resistance were identified and located on LG 1, 2, 4 and 6, respectively, explaining 5.2%-21.0% of the phenotypic variation. Three consistent QTLs (pm1.1, pm2.1 and pm4.1) were detected under the two test conditions. The QTL pm6.1 was only identified in 2005/Autumn. The total phenotypic variation explained by the QTLs was 52.0% and 42.0% in 2005/Autumn and 2006/Spring, respectively. Anchor markers tightly linked to those loci (<5 cM) could lay a basis for both molecular marker-assisted breeding and map-based gene cloning of the PM-resistance gene in cucumber.

  3. SSR Inheritance Analysis and Screening for Linked Marker of Powdery Mildew Resistance in Cucumber(Cucumis sativus L.)%黄瓜白粉病抗性遗传分析与连锁标记筛选

    Institute of Scientific and Technical Information of China (English)

    聂京涛; 潘俊松; 何欢乐; 司龙亭; 蔡润

    2011-01-01

    In order to accelerate molecular marker assisted breeding process of powdery mildew resistance in cucumber ( Cucumis sativus L.) , in this paper, high susceptible cucumber inbred line M 12,abd high resistant inbred line M3 to powdery mildew were taken as parent and their hybrid, F2 populations and BC1 populations were used as experimental materials.We identified the seedlings inoculated with powdery mildew fungus and probed into the genetic regulation of powdery mildew resistance in cucumber.Combing with BSA method and SSR technology, SSR markers linked to the major resistant gene of powdery mildew in cucumber was obtained.The results showed that the resistance to powdery mildew was mainly controlled by a single recessive gene.By analyzing F2 single plant with SSR technique, a marker SSR15592 linked to the resistant gene was identified.The genetic distance between this marker and resistant gene was 7.62 cM.%以黄瓜高感、高抗白粉病自交系M12、M3为亲本组合得到的F2群体和BC1群体为试材,采用苗期接种鉴定,探讨了黄瓜白粉病抗性的遗传规律;结合BSA法和SSR技术,获得了与黄瓜白粉病抗性主效基因连锁的SSR标记.结果表明,供试亲本间白粉病抗性主要受一隐性单基因控制.对F2单株进行SSR分析,鉴定出1个与黄瓜白粉病抗性基因连锁的标记SSR15592,该标记与抗性基因间的遗传距离为7.62 cM.

  4. Chromosomal location and comparative genomics analysis of powdery mildew resistance gene Pm51 in a putative wheat-Thinopyrum ponticum introgression line.

    Science.gov (United States)

    Zhan, Haixian; Li, Guangrong; Zhang, Xiaojun; Li, Xin; Guo, Huijuan; Gong, Wenping; Jia, Juqing; Qiao, Linyi; Ren, Yongkang; Yang, Zujun; Chang, Zhijian

    2014-01-01

    Powdery mildew (PM) is a very destructive disease of wheat (Triticum aestivum L.). Wheat-Thinopyrum ponticum introgression line CH7086 was shown to possess powdery mildew resistance possibly originating from Th. ponticum. Genomic in situ hybridization and molecular characterization of the alien introgression failed to identify alien chromatin. To study the genetics of resistance, CH7086 was crossed with susceptible genotypes. Segregation in F2 populations and F2:3 lines tested with Chinese Bgt race E09 under controlled conditions indicated that CH7086 carries a single dominant gene for powdery mildew resistance. Fourteen SSR and EST-PCR markers linked with the locus were identified. The genetic distances between the locus and the two flanking markers were 1.5 and 3.2 cM, respectively. Based on the locations of the markers by nullisomic-tetrasomic and deletion lines of 'Chinese Spring', the resistance gene was located in deletion bin 2BL-0.89-1.00. Conserved orthologous marker analysis indicated that the genomic region flanking the resistance gene has a high level of collinearity to that of rice chromosome 4 and Brachypodium chromosome 5. Both resistance specificities and tests of allelism suggested the resistance gene in CH7086 was different from previously reported powdery mildew resistance genes on 2BL, and the gene was provisionally designated PmCH86. Molecular analysis of PmCH86 compared with other genes for resistance to Bgt in the 2BL-0.89-1.00 region suggested that PmCH86 may be a new PM resistance gene, and it was therefore designated as Pm51. The closely linked flanking markers could be useful in exploiting this putative wheat-Thinopyrum translocation line for rapid transfer of Pm51 to wheat breeding programs.

  5. Insights into the recent emergence of powdery mildew on its 'new' host triticale: from origin to disease control.

    Science.gov (United States)

    Troch, Veronique; Audenaert, Kris; Bekaert, Boris; Höfte, Monica; Haesaert, Geert

    2014-01-01

    The development of new crop species and their associated agro-ecosystems led simultaneously to the emergence of new pathogens (Stukenbrock and McDonald, 2008). This research focused on the recent emergence of powdery mildew (Blumeria graminis) on triticale (x Triticosecale Wittmack). In a first part, we aimed to gain insights into the evolutionary origin of this pathogen on its new host. A secondary aim was to investigate the presence of powdery mildew resistance in current commercial triticale cultivars, including its cellular basis of resistance. To address these research goals, we have pursued a molecular, pathological and cytological approach. This discussion will reflect on the experimental findings described in this research and their impact for future management of powdery mildew on triticale and other cereals.

  6. Adult plant and seedling resistance to powdery mildew in a Triticum aestivum x Triticum militinae hybrid line.

    Science.gov (United States)

    Jakobson, Irena; Peusha, Hilma; Timofejeva, Ljudmilla; Järve, Kadri

    2006-02-01

    In the progeny of a cross between the common wheat cultivar Tähti and Triticum militinae, a member of the timopheevii group of tetraploid wheats, several hybrid lines were selected that are characterized by improved seedling and adult plant resistance (APR) to powdery mildew. An F2 single-seed descendant mapping population segregating for seedling resistance and APR to powdery mildew was analysed for the identification of quantitative trait loci (QTL). The main QTL responsible for APR was detected on the long arm of chromosome 4A tightly linked to the Xgwm160 locus on a T. militinae translocation explaining up to 54% of phenotypic variance. The same translocation influenced seedling resistance to powdery mildew upon inoculation of plants with a synthetic population of Blumeria graminis DC. f. sp. tritici, and explained 28-33% of the phenotypic variance.

  7. Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew [Podosphaera leucotricha (Ell. et Ev. Salmon

    Directory of Open Access Journals (Sweden)

    Zbigniew Borecki

    2013-12-01

    Full Text Available Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew was evaluated in 1983-1986. Four groups of susceptibility were distinguished. None of the 13 tested scab-resistant apple trees exhibited complete field immunity to apple powdery mildew. Two cultivars, 'Prima' and 'Primula', were practically resistant. 'Liberty' and two numbered selections, NY-140-9 and NY-158-2, belonged to the group of lower susceptibility. Moderate susceptibility was shown by: 'Novamac', 'Freedom', 'Gavin', 'Prima' and 'Florina'. The group of apple trees most susceptible to Podosphaera leucotricha included: 'Macfree', 'Priscilla' and 'Nova Easygro'. It is not necessary to use chemical sprays to control powdery mildew on 'Prima' and 'Primula'. A reduced spraying program may be recommended only under high disease pressure on less susceptible apple cultivars. A regular spray schedule is needed on moderately susceptible apple trees, but improved chemical control is necessary on the most susceptible ones.

  8. Differences in early callose deposition during adapted and non-adapted powdery mildew infection of resistant Arabidopsis lines.

    Science.gov (United States)

    Naumann, Marcel; Somerville, Shauna; Voigt, Christian

    2013-06-01

    The deposition of callose, a (1,3)-β-glucan cell wall polymer, can play an essential role in the defense response to invading pathogens. We could recently show that Arabidopsis thaliana lines with an overexpression of the callose synthase gene PMR4 gained complete penetration resistance to the adapted powdery mildew Golovinomyces cichoracearum and the non-adapted powdery mildew Blumeria graminis f. sp hordei. The penetration resistance is based on the transport of the callose synthase PMR4 to the site of attempted fungal penetration and the subsequent formation of enlarged callose deposits. The deposits differed in their total diameter comparing both types of powdery mildew infection. In this study, further characterization of these callose deposits revealed that size differences were especially pronounced in the core region of the deposits. This suggests that specific, pathogen-dependent factors exist, which might regulate callose synthase transport to the core region of forming deposits.

  9. Genetic and comparative genomics mapping reveals that a powdery mildew resistance gene Ml3D232 originating from wild emmer co-segregates with an NBS-LRR analog in common wheat (Triticum aestivum L.).

    Science.gov (United States)

    Zhang, Hongtao; Guan, Haiying; Li, Jingting; Zhu, Jie; Xie, Chaojie; Zhou, Yilin; Duan, Xiayu; Yang, Tsomin; Sun, Qixin; Liu, Zhiyong

    2010-11-01

    Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most important wheat diseases worldwide and breeding for resistance using diversified disease resistance genes is the most promising approach to prevent outbreaks of powdery mildew. A powdery mildew resistance gene, originating from wild emmer wheat (Triticum turgidum var. dicoccoides) accessions collected from Israel, has been transferred into the hexaploid wheat line 3D232 through crossing and backcrossing. Inoculation results with 21 B. graminis f. sp. tritici races indicated that 3D232 is resistant to all of the powdery mildew isolates tested. Genetic analyses of 3D232 using an F(2) segregating population and F(3) families indicated that a single dominant gene, Ml3D232, confers resistance in the host seedling stage. By applying molecular markers and bulked segregant analysis (BSA), we have identified polymorphic simple sequence repeats (SSR), expressed sequence tags (EST) and derived sequence tagged site (STS) markers to determine that the Ml3D232 is located on chromosome 5BL bin 0.59-0.76. Comparative genetic analyses using mapped EST markers and genome sequences of rice and Brachypodium established co-linearity of the Ml3D232 genomic region with a 1.4 Mb genomic region on Brachypodium distachyon chromosome 4, and a 1.2 Mb contig located on the Oryza sativa chromosome 9. Our comparative approach enabled us to develop new EST-STS markers and to delimit the genomic region carrying Ml3D232 to a 0.8 cM segment that is collinear with a 558 kb region on B. distachyon. Eight EST markers, including an NBS-LRR analog, co-segregated with Ml3D232 to provide a target site for fine genetic mapping, chromosome landing and map-based cloning of the powdery mildew resistance gene. This newly developed common wheat germplasm provides broad-spectrum resistance to powdery mildew and a valuable resource for wheat breeding programs.

  10. Identification and characterization of wheat long non-protein coding RNAs responsive to powdery mildew infection and heat stress by using microarray analysis and SBS sequencing

    Directory of Open Access Journals (Sweden)

    Peng Huiru

    2011-04-01

    Full Text Available Abstract Background Biotic and abiotic stresses, such as powdery mildew infection and high temperature, are important limiting factors for yield and grain quality in wheat production. Emerging evidences suggest that long non-protein coding RNAs (npcRNAs are developmentally regulated and play roles in development and stress responses of plants. However, identification of long npcRNAs is limited to a few plant species, such as Arabidopsis, rice and maize, no systematic identification of long npcRNAs and their responses to abiotic and biotic stresses is reported in wheat. Results In this study, by using computational analysis and experimental approach we identified 125 putative wheat stress responsive long npcRNAs, which are not conserved among plant species. Among them, some were precursors of small RNAs such as microRNAs and siRNAs, two long npcRNAs were identified as signal recognition particle (SRP 7S RNA variants, and three were characterized as U3 snoRNAs. We found that wheat long npcRNAs showed tissue dependent expression patterns and were responsive to powdery mildew infection and heat stress. Conclusion Our results indicated that diverse sets of wheat long npcRNAs were responsive to powdery mildew infection and heat stress, and could function in wheat responses to both biotic and abiotic stresses, which provided a starting point to understand their functions and regulatory mechanisms in the future.

  11. A Cluster of Nucleotide-Binding Site-Leucine-Rich Repeat Genes Resides in a Barley Powdery Mildew Resistance Quantitative Trait Loci on 7HL.

    Science.gov (United States)

    Cantalapiedra, Carlos P; Contreras-Moreira, Bruno; Silvar, Cristina; Perovic, Dragan; Ordon, Frank; Gracia, María Pilar; Igartua, Ernesto; Casas, Ana M

    2016-07-01

    Powdery mildew causes severe yield losses in barley production worldwide. Although many resistance genes have been described, only a few have already been cloned. A strong QTL (quantitative trait locus) conferring resistance to a wide array of powdery mildew isolates was identified in a Spanish barley landrace on the long arm of chromosome 7H. Previous studies narrowed down the QTL position, but were unable to identify candidate genes or physically locate the resistance. In this study, the exome of three recombinant lines from a high-resolution mapping population was sequenced and analyzed, narrowing the position of the resistance down to a single physical contig. Closer inspection of the region revealed a cluster of closely related NBS-LRR (nucleotide-binding site-leucine-rich repeat containing protein) genes. Large differences were found between the resistant lines and the reference genome of cultivar Morex, in the form of PAV (presence-absence variation) in the composition of the NBS-LRR cluster. Finally, a template-guided assembly was performed and subsequent expression analysis revealed that one of the new assembled candidate genes is transcribed. In summary, the results suggest that NBS-LRR genes, absent from the reference and the susceptible genotypes, could be functional and responsible for the powdery mildew resistance. The procedure followed is an example of the use of NGS (next-generation sequencing) tools to tackle the challenges of gene cloning when the target gene is absent from the reference genome.

  12. A Cluster of Nucleotide-Binding Site–Leucine-Rich Repeat Genes Resides in a Barley Powdery Mildew Resistance Quantitative Trait Loci on 7HL

    Directory of Open Access Journals (Sweden)

    Carlos P. Cantalapiedra

    2016-07-01

    Full Text Available Powdery mildew causes severe yield losses in barley production worldwide. Although many resistance genes have been described, only a few have already been cloned. A strong QTL (quantitative trait locus conferring resistance to a wide array of powdery mildew isolates was identified in a Spanish barley landrace on the long arm of chromosome 7H. Previous studies narrowed down the QTL position, but were unable to identify candidate genes or physically locate the resistance. In this study, the exome of three recombinant lines from a high-resolution mapping population was sequenced and analyzed, narrowing the position of the resistance down to a single physical contig. Closer inspection of the region revealed a cluster of closely related NBS-LRR (nucleotide-binding site–leucine-rich repeat containing protein genes. Large differences were found between the resistant lines and the reference genome of cultivar Morex, in the form of PAV (presence-absence variation in the composition of the NBS-LRR cluster. Finally, a template-guided assembly was performed and subsequent expression analysis revealed that one of the new assembled candidate genes is transcribed. In summary, the results suggest that NBS-LRR genes, absent from the reference and the susceptible genotypes, could be functional and responsible for the powdery mildew resistance. The procedure followed is an example of the use of NGS (next-generation sequencing tools to tackle the challenges of gene cloning when the target gene is absent from the reference genome.

  13. Molecular cytogenetic identification of a wheat– Thinopyrum ponticum translocation line resistant to powdery mildew

    Indian Academy of Sciences (India)

    FANG HE; YINGUANG BAO; XIAOLEI QI; YINGXUE MA; XINGFENG LI; HONGGANG WANG

    2017-03-01

    Thinopyrum ponticum (2n = 70) serves as a valuable gene pool for wheat improvement. Line SN0224, derived from crosses between Th. ponticum and the common wheat cultivar Yannong15, was identified in the present study. Cytogenetic observations showed that SN0224 contains 42 chromosomes in the root-tip cells and 21 bivalents in the pollen mother cells, therebydemonstrating its cytogenetic stability. Genomic in situ hybridization, probed with the total genomic DNA of Th. ponticum, produced hybridization signals in the distal region of two wheat chromosome arms. After inoculation with the Blumeriagraminis f. sp. tritici (Bgt) isolates, SN0224 exhibited immunity. Segregation in F1s and F2s from the cross SN0224/cv. Huixianhong indicated that SN0224 carries a single dominant gene for powdery mildew (Pm) resistance, which was temporarily designated PmSn0224. Three markers Barc212, Xwmc522 and Xbarc1138 were detected to be linked with PmSn0224. Based on the locations of the markers, PmSn0224 was located on the chromosome 2A. None of the three markers above is linked with the previously reported PM resistance genes on chromosome 2A, and none of the previously reported PM resistance genes on chromosome 2A is related to Th. ponticum. Therefore, PmSn0224 is likely a novel gene putatively from Th. ponticum.

  14. Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew.

    Science.gov (United States)

    Wang, Yanpeng; Cheng, Xi; Shan, Qiwei; Zhang, Yi; Liu, Jinxing; Gao, Caixia; Qiu, Jin-Long

    2014-09-01

    Sequence-specific nucleases have been applied to engineer targeted modifications in polyploid genomes, but simultaneous modification of multiple homoeoalleles has not been reported. Here we use transcription activator-like effector nuclease (TALEN) and clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (refs. 4,5) technologies in hexaploid bread wheat to introduce targeted mutations in the three homoeoalleles that encode MILDEW-RESISTANCE LOCUS (MLO) proteins. Genetic redundancy has prevented evaluation of whether mutation of all three MLO alleles in bread wheat might confer resistance to powdery mildew, a trait not found in natural populations. We show that TALEN-induced mutation of all three TaMLO homoeologs in the same plant confers heritable broad-spectrum resistance to powdery mildew. We further use CRISPR-Cas9 technology to generate transgenic wheat plants that carry mutations in the TaMLO-A1 allele. We also demonstrate the feasibility of engineering targeted DNA insertion in bread wheat through nonhomologous end joining of the double-strand breaks caused by TALENs. Our findings provide a methodological framework to improve polyploid crops.

  15. 秦岭主要林区白粉菌分类研究初报%Preliminary Study on Taxonomy of Powdery Mildews in Qinling Mountains

    Institute of Scientific and Technical Information of China (English)

    白露超; 曹支敏; 代拴法; 姚三中

    2012-01-01

    依据国际新的白粉菌分类系统,采用传统形态学分类与无性型个体发育及其超微结构相结合的方法,对采自秦岭主要林区的白粉菌进行了分类鉴定.共鉴定出白粉菌5族、9属、61种,并列出了白粉菌名录,涉及森林植物36科、72属、112种,其中1种为白粉菌的寄主新纪录.%Based on the new classification system of Erysiphales, a total of 5 tribes, 9 genera, 61 species of powdery mildew from Qinling Mountains were identified) classified by traditional morphology, the ontogenesis and the ul-trastructures of conidia. A checklist was provided Thirty six families, 72 genera, 112 species, in which 1 species (Duchesnea indica) is new record of powdery mildew, of host plants and their geographical distributions were reported in the checklist pertain to 61 species of powdery mildew.

  16. Biological control of the cucurbit powdery mildew pathogen Podosphaera xanthii by means of the epiphytic fungus Pseudozyma aphidis and parasitism as a mode of action.

    Science.gov (United States)

    Gafni, Aviva; Calderon, Claudia E; Harris, Raviv; Buxdorf, Kobi; Dafa-Berger, Avis; Zeilinger-Reichert, Einat; Levy, Maggie

    2015-01-01

    Epiphytic yeasts, which colonize plant surfaces, may possess activity that can be harnessed to help plants defend themselves against various pathogens. Due to their unique characteristics, epiphytic yeasts belonging to the genus Pseudozyma hold great potential for use as biocontrol agents. We identified a unique, biologically active isolate of the epiphytic yeast Pseudozyma aphidis that is capable of inhibiting Botrytis cinerea via a dual mode of action, namely induced resistance and antibiosis. Here, we show that strain L12 of P. aphidis can reduce the severity of powdery mildew caused by Podosphaera xanthii on cucumber plants with an efficacy of 75%. Confocal and scanning electron microscopy analyses demonstrated P. aphidis proliferation on infected tissue and its production of long hyphae that parasitize the powdery mildew hyphae and spores as an ectoparasite. We also show that crude extract of P. aphidis metabolites can inhibit P. xanthii spore germination in planta. Our results suggest that in addition to its antibiosis as mode of action, P. aphidis may also act as an ectoparasite on P. xanthii. These results indicate that P. aphidis strain L12 has the potential to control powdery mildew.

  17. Biological control of the cucurbit powdery mildew pathogen Podosphaera xanthii by means of the epiphytic fungus Pseudozyma aphidis and parasitism as a mode of action

    Directory of Open Access Journals (Sweden)

    Aviva eGafni

    2015-03-01

    Full Text Available Epiphytic yeasts, which colonize plant surfaces, may possess activity that can be harnessed to help plants defend themselves against various pathogens. Due to their unique characteristics, epiphytic yeasts belonging to the genus Pseudozyma hold great potential for use as biocontrol agents. We identified a unique, biologically active isolate of the epiphytic yeast Pseudozyma aphidis that is capable of inhibiting Botrytis cinerea via a dual mode of action, namely induced resistance and antibiosis. Here, we show that strain L12 of P. aphidis can reduce the severity of powdery mildew caused by Podosphaera xanthii on cucumber plants with an efficacy of 75%. Confocal and scanning electron microscopy analyses demonstrated P. aphidis proliferation on infected tissue and its production of long hyphae that parasitize the powdery mildew hyphae and spores as an ectoparasite. We also show that crude extract of P. aphidis metabolites can inhibit P. xanthii spore germination in planta. Our results suggest that in addition to its antibiosis mode of action, P. aphidis may also act as an ectoparasite on P. xanthii. These results indicate that P. aphidis strain L12 has the potential to control powdery mildew.

  18. Molecular Cytogenetic Identification of a Wheat-Thinopyron intermedium (Host) Barkworth & DR Dewey Partial Amphiploid Resistant to Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    Shu-Bing LIU; Hong-Gang WANG; Xue-Yong ZHANG; Xing-Feng LI; Da-Yong LI; Xia-Yu DUAN; Yi-Lin ZHOU

    2005-01-01

    Wide cross and molecular cytogenetic methods were used to transfer the powdery mildew resistance gene from Thinopyron intermedium (Host) Barkworth & DR Dewey to wheat. Among the progeny of crossing common wheat (Triticum aestivum L.) Yannong 15 with Th. intermedium, a partial amphiploid E990256, with resistance to powdery mildew, was developed. It had 56 chromosomes and could form 28bivalents in pollen mother cells at metaphase I of meiosis. Resistance verification by race 15 at the seedling stage and by mixed strains of Erysiphales gramnis DC. f. sp. tritici Em. Marchal at the adult stage showed it was immune to powdery mildew at both stages. Gene postulation via 21 isolates of E. gramnis f. sp. tritici and 29 differential hosts showed it was nearly immune to all the isolates used, and its resistance pattem was different from all the mildew resistance genes used, which indicated it probably contained a new resistance gene to powdery mildew. Biochemical verification showed it might convey different Th. intermedium chromosomes from those of the wheat-Th. intermedium partial amphiploids Zhong 1-5. Genomic in situ hybridization analysis by using St genomic DNA as the probe showed E990256 contained a recombination genome of St and E.

  19. Preventative and Curative Effects of Several Plant Derived Agents Against Powdery Mildew Disease of Okra

    Directory of Open Access Journals (Sweden)

    Moustafa Hemdan Ahmed MOHARAM

    2012-08-01

    Full Text Available The preventative and curative effects of some plant derived agents based on plant extracts or essential oils were studied at different concentrations against Erysiphe cichoracearum DC. ex Merat, the causal pathogen of okra powdery mildew by the detached leaf-disk and potted plants bioassays. Through detached leaf-disk assay, the highest mean preventative effect (97.74% was recorded by neem seed oil followed by jojoba oil (89.82% and extract of Rynoutria sachalinensis (82.77%. Neem seed oil at 1% was the most effective agent followed by jojoba oil and extract of R. sachalinensis at 1.5% and 2%, respectively, where they suppressed E. cichoracearum completely. Potted plants assay revealed that neem seed oil, jojoba oil and extract of R. sachalinensis as well as the fungicide (active ingredient dinocap showed higher preventative efficacy at all leaf olds treated after 7 and 14 days of inoculation as compared with extracts of henna and garlic. Moreover, the preventative efficacy partly remained apparent after 14 days of inoculation at all leaf olds tested. In field trials through 2010 and 2011 growing seasons, when the first symptoms of powdery mildew appeared naturally, 1.5% jojoba oil, 2% extract of R. sachalinensis and 1% neem seed oil were sprayed individually twice on grown plants to evaluate their efficacy on controlling powdery mildew, growth and yield of okra. Resulted showed that neem seed oil was the most effective agent and highly decreased the disease severity to 29.92%, recorded the highly curative effect (68.15% and also improved plant growth and pods yield.

  20. Strategies for RUN1 Deployment Using RUN2 and REN2 to Manage Grapevine Powdery Mildew Informed by Studies of Race Specificity.

    Science.gov (United States)

    Feechan, Angela; Kocsis, Marianna; Riaz, Summaira; Zhang, Wei; Gadoury, David M; Walker, M Andrew; Dry, Ian B; Reisch, Bruce; Cadle-Davidson, Lance

    2015-08-01

    The Toll/interleukin-1 receptor nucleotide-binding site leucine-rich repeat gene, "resistance to Uncinula necator 1" (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic V. vinifera cultivars. However, sporulating powdery mildew colonies and cleistothecia of the heterothallic pathogen have been found on introgression lines containing the RUN1 locus growing in New York (NY). Two E. necator isolates collected from RUN1 vines were designated NY1-131 and NY1-137 and were used in this study to inform a strategy for durable RUN1 deployment. In order to achieve this, fitness parameters of NY1-131 and NY1-137 were quantified relative to powdery mildew isolates collected from V. rotundifolia and V. vinifera on vines containing alleles of the powdery mildew resistance genes RUN1, RUN2, or REN2. The results clearly demonstrate the race specificity of RUN1, RUN2, and REN2 resistance alleles, all of which exhibit programmed cell death (PCD)-mediated resistance. The NY1 isolates investigated were found to have an intermediate virulence on RUN1 vines, although this may be allele specific, while the Musc4 isolate collected from V. rotundifolia was virulent on all RUN1 vines. Another powdery mildew resistance locus, RUN2, was previously mapped in different V. rotundifolia genotypes, and two alleles (RUN2.1 and RUN2.2) were identified. The RUN2.1 allele was found to provide PCD-mediated resistance to both an NY1 isolate and Musc4. Importantly, REN2 vines were resistant to the NY1 isolates and RUN1REN2 vines combining both genes displayed additional resistance. Based on these results, RUN1-mediated resistance in grapevine may be enhanced by pyramiding with RUN2.1 or REN2; however, naturally occurring isolates in North America display some virulence on vines with these resistance genes. The characterization of additional resistance sources is needed to identify

  1. Ozone and sulphur dioxide effects on the lilac powdery mildew fungus

    Energy Technology Data Exchange (ETDEWEB)

    Hibben, C.R.; Taylor, M.P.

    1975-01-01

    Colonisation of lilac (Syringa vulgaris) by the powdery mildew fungus (Microsphaera alni) is often sparse in sites exposed to urban air pollutants. The influence of ozone(O/sub 3/) and sulphur dioxide (SO/sub 2/) on conidial germination and the establishment of infection by M. alni was studied. Although tolerant of O/sub 3/, mildew infection was reduced by acute and chronic doses of SO/sub 2/. Conidial germination and the appressorium phase were the stages most sensitive to SO/sub 2/. Infection was unimpeded on leaves previously fumigated, thus confirming that these reactions were due more to the fungicidal, rather than the phytotoxic, properties of the pollutant. There was no synergism between the two gases that lowered the threshold of toxicity to conidia. A member of the Fungi Imperfecti, Hyalodendron album, sporulated on mildew colonies on lilac leaves. It was antagonistic to the mildew by reducing both conidial germination and the formation of appressoria. Conidia of H. album were more sensitive to O/sub 3/ and SO/sub 2/ than M. alni. These results suggest that the role of nonpathogenic microbial epiphytes should be considered when assessing the full impact of air pollutants on obligate parasites, and possibly on other foliar pathogens.

  2. 植物白粉病的化学防治进展%Development of Chemical Control for Powdery Mildew on Plants

    Institute of Scientific and Technical Information of China (English)

    周益林; 段霞瑜; 盛宝钦

    2001-01-01

    Powdery mildew is a type of important disease on plants, and fungicides is a main mean for controlling powdery mildew. The development and history of chemical control for powdery mildew was briefly reviewed, and some important fungicides and the mechanism of their action were introduced.%对植物白粉病的化学防治历史和发展进行了综述,同时介绍了一些重要的药剂及其作用机制,并讨论了白粉病化学防治中存在的问题。

  3. Infestation of transgenic powdery mildew-resistant wheat by naturally occurring insect herbivores under different environmental conditions.

    Directory of Open Access Journals (Sweden)

    Fernando Álvarez-Alfageme

    Full Text Available A concern associated with the growing of genetically modified (GM crops is that they could adversely affect non-target organisms. We assessed the impact of several transgenic powdery mildew-resistant spring wheat lines on insect herbivores. The GM lines carried either the Pm3b gene from hexaploid wheat, which confers race-specific resistance to powdery mildew, or the less specific anti-fungal barley seed chitinase and β-1,3-glucanase. In addition to the non-transformed control lines, several conventional spring wheat varieties and barley and triticale were included for comparison. During two consecutive growing seasons, powdery mildew infection and the abundance of and damage by naturally occurring herbivores were estimated under semi-field conditions in a convertible glasshouse and in the field. Mildew was reduced on the Pm3b-transgenic lines but not on the chitinase/glucanase-expressing lines. Abundance of aphids was negatively correlated with powdery mildew in the convertible glasshouse, with Pm3b wheat plants hosting significantly more aphids than their mildew-susceptible controls. In contrast, aphid densities did not differ between GM plants and their non-transformed controls in the field, probably because of low mildew and aphid pressure at this location. Likewise, the GM wheat lines did not affect the abundance of or damage by the herbivores Oulema melanopus (L. and Chlorops pumilionis Bjerk. Although a previous study has revealed that some of the GM wheat lines show pleiotropic effects under field conditions, their effect on herbivorous insects appears to be low.

  4. Identification and translocation of metabolites from powdery mildew resistant rootstocks to susceptible watermelon scions using nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Watermelon (Citrullus lanatus), an important commercial crop, and nutritious fruit, is high in antioxidants, vitamins, and lycopene. Powdery mildew (PM) is a serious disease caused by Podosphaera xanthii, which significantly reduces watermelon production in the U.S. and other parts of the world. C...

  5. Distribution and characterization of Podosphaera macularis virulent on hop cultivars possessing R6-based resistance to powdery mildew

    Science.gov (United States)

    In 2012, an epidemic of powdery mildew occurred in Washington and Idaho on previously resistant cultivars whose resistance was putatively based on the gene designated R6. In 2013, isolates capable of causing severe disease on cultivars with R6-based resistance were confirmed in Oregon and became wid...

  6. Initiative for international cooperation of researchers and breeders related to determination and denomination of cucurbit powdery mildew races

    Science.gov (United States)

    Cucurbit powdery mildew (CPM) is caused most frequently by two obligate erysiphaceous ectoparasites, Golovinomyces orontii s.l. and Podosphaera xanthii, that are highly variable in virulence. Various independent systems of CPM race determination and denomination cause a chaotic situation in cucurbit...

  7. ‘Appalachian Joy’ is a supernumery, white-bracted cultivar of cornus florida resistant to powdery mildew

    Science.gov (United States)

    The wholesale nursery industry in Tennessee contributes more than $200 million to the annual economy of the state and are in excess of $50 million annually for flowering dogwood (Cornus florida). Two fungal diseases, dogwood anthracnose and powdery mildew (Discula destructiva and Erysiphe pulchra, r...

  8. Studies in plant pathogenic fungi—II. On some powdery mildews (Erysiphales) recently recorded from the Netherlands

    NARCIS (Netherlands)

    Noordeloos, M.E.; Loerakker, W.M.

    1989-01-01

    Full descriptions and notes on their pathogenous properties are given of the anamorphs of four powdery mildews recently recorded as new from the Netherlands. Two are described as new species, viz. Oidium longipes on Solarium melongena and O. limnanthis on Limnanthes alba. Oidium lycopersicum Cooke &

  9. A disulphide isomerase gene (PDI-V) from Haynaldia villosa contributes to powdery mildew resistance in common wheat.

    Science.gov (United States)

    Faheem, Muhammad; Li, Yingbo; Arshad, Muhammad; Jiangyue, Cheng; Jia, Zhao; Wang, Zongkuan; Xiao, Jin; Wang, Haiyan; Cao, Aizhong; Xing, Liping; Yu, Feifei; Zhang, Ruiqi; Xie, Qi; Wang, Xiue

    2016-04-13

    In this study, we report the contribution of a PDI-like gene from wheat wild relative Haynaldia villosa in combating powdery mildew. PDI-V protein contains two conserved thioredoxin (TRX) active domains (a and a') and an inactive domain (b). PDI-V interacted with E3 ligase CMPG1-V protein, which is a positive regulator of powdery mildew response. PDI-V was mono-ubiquitinated by CMPG1-V without degradation being detected. PDI-V was located on H. villosa chromosome 5V and encoded for a protein located in the endoplasmic reticulum. Bgt infection in leaves of H. villosa induced PDI-V expression. Virus induced gene silencing of PDIs in a T. durum-H. villosa amphiploid compromised the resistance. Single cell transient over-expression of PDI-V or a truncated version containing the active TXR domain a decreased the haustorial index in moderately susceptible wheat cultivar Yangmai 158. Stable transgenic lines over-expressing PDI-V in Yangmai 158 displayed improved powdery mildew resistance at both the seedling and adult stages. By contrast over-expression of point-mutated PDI-V(C57A) did not increase the level of resistance in Yangmai 158. The above results indicate a pivotal role of PDI-V in powdery mildew resistance and showed that conserved TRX domain a is critical for its function.

  10. Pea powdery mildew er1 resistance is associated to loss-of-function mutations at a MLO homologous locus.

    Science.gov (United States)

    Pavan, Stefano; Schiavulli, Adalgisa; Appiano, Michela; Marcotrigiano, Angelo R; Cillo, Fabrizio; Visser, Richard G F; Bai, Yuling; Lotti, Concetta; Ricciardi, Luigi

    2011-12-01

    The powdery mildew disease affects several crop species and is also one of the major threats for pea (Pisum sativum L.) cultivation all over the world. The recessive gene er1, first described over 60 years ago, is well known in pea breeding, as it still maintains its efficiency as a powdery mildew resistance source. Genetic and phytopathological features of er1 resistance are similar to those of barley, Arabidopsis, and tomato mlo powdery mildew resistance, which is caused by the loss of function of specific members of the MLO gene family. Here, we describe the obtainment of a novel er1 resistant line by experimental mutagenesis with the alkylating agent diethyl sulfate. This line was found to carry a single nucleotide polymorphism in the PsMLO1 gene sequence, predicted to result in premature termination of translation and a non-functional protein. A cleaved amplified polymorphic sequence (CAPS) marker was developed on the mutation site and shown to be fully co-segregating with resistance in F(2) individuals. Sequencing of PsMLO1 from three powdery mildew resistant cultivars also revealed the presence of loss-of-function mutations. Taken together, results reported in this study strongly indicate the identity between er1 and mlo resistances and are expected to be of great breeding importance for the development of resistant cultivars via marker-assisted selection.

  11. Mapping of novel powdery mildew resistance gene Pm53 introgressed from Aegilops speltoides into soft red winter wheat

    Science.gov (United States)

    Powdery mildew of wheat (Triticum aestivum L.) is a major fungal disease in many areas of the world, caused by Blumeria graminis f.sp. tritici (Bgt). Host plant resistance is the preferred form of disease prevention because it is both economical and environmentally benign. Identification of new resi...

  12. Genetic mapping of MlUM15: an Aegilops neglecta-derived powdery mildew resistance gene in common wheat

    Science.gov (United States)

    Powdery mildew, caused by Blumeria graminis DC f. sp. tritici, is a major fungal disease of wheat (Triticum aestivum L.) in cool and humid climates. Race-specific host plant resistance is a reliable, economical, and environmentally benign form of disease prevention. The identification of molecular m...

  13. Preliminary evaluation of resistance to powdery mildew (Podosphaera xanthii) in AVRDC collections of bitter gourd (Momordica charantia L.)

    Science.gov (United States)

    Bitter gourd (Momordica charantia L.) is an important market vegetable in Asia, where it is also used in folk medicine to manage type 2 diabetes. Powdery mildew caused by Podosphaera xanthii is a serious fungal disease of bitter gourd and yield losses of up to 50% have been reported. After observi...

  14. On-farm and on-station evaluations of three orchard management approaches against apple scab and apple powdery mildew

    NARCIS (Netherlands)

    Holb, I.J.; Abonyi, F.; Buurma, J.; Heijne, B.

    2017-01-01

    In a three-year study (from 2012 to 2014), the efficacy of three apple management approaches (conventional, standard and advanced Integrated Pest Management - CON, IPM1 and IPM2, respectively) was aimed to investigate against apple scab and apple powdery mildew in on-station (small research scale)

  15. Potential Sources of Resistance to Cucurbit Powdery Mildew in US Plant Introductions (PI) of Lagenaria Siceraria (bottle gourd)

    Science.gov (United States)

    Powdery mildew (Podosphaera xanthii) can cause severe damage to cucurbit crops grown in open fields and greenhouses. In recent years, there has been a growing interest in the USA in grafting watermelon plants onto various cucurbit rootstocks. Bottle gourd plants (Lagenaria siceraria) are being use...

  16. Genome-wide association study for crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) resistance in an oat (Avena sativa) collection of commercial varieties and landraces.

    Science.gov (United States)

    Montilla-Bascón, Gracia; Rispail, Nicolas; Sánchez-Martín, Javier; Rubiales, Diego; Mur, Luis A J; Langdon, Tim; Howarth, Catherine J; Prats, Elena

    2015-01-01

    Diseases caused by crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) are among the most important constraints for the oat crop. Breeding for resistance is one of the most effective, economical, and environmentally friendly means to control these diseases. The purpose of this work was to identify elite alleles for rust and powdery mildew resistance in oat by association mapping to aid selection of resistant plants. To this aim, 177 oat accessions including white and red oat cultivars and landraces were evaluated for disease resistance and further genotyped with 31 simple sequence repeat and 15,000 Diversity Arrays Technology (DArT) markers to reveal association with disease resistance traits. After data curation, 1712 polymorphic markers were considered for association analysis. Principal component analysis and a Bayesian clustering approach were applied to infer population structure. Five different general and mixed linear models accounting for population structure and/or kinship corrections and two different statistical tests were carried out to reduce false positive. Five markers, two of them highly significant in all models tested were associated with rust resistance. No strong association between any marker and powdery mildew resistance at the seedling stage was identified. However, one DArT sequence, oPt-5014, was strongly associated with powdery mildew resistance in adult plants. Overall, the markers showing the strongest association in this study provide ideal candidates for further studies and future inclusion in strategies of marker-assisted selection.

  17. The genetics of resistance to powdery mildew in cultivated oats (Avena sativa L.): current status of major genes.

    Science.gov (United States)

    Hsam, Sai L K; Mohler, Volker; Zeller, Friedrich J

    2014-05-01

    The genetics of resistance to powdery mildew caused by Blumeria graminis f. sp. avenae of four cultivated oats was studied using monosomic analysis. Cultivar 'Bruno' carries a gene (Pm6) that shows a recessive mode of inheritance and is located on chromosome 10D. Cultivar 'Jumbo' possesses a dominant resistance gene (Pm1) on chromosome 1C. In cultivar 'Rollo', in addition to the gene Pm3 on chromosome 17A, a second dominant resistance gene (Pm8) was identified and assigned to chromosome 4C. In breeding line APR 122, resistance was conditioned by a dominant resistance gene (Pm7) that was allocated to chromosome 13A. Genetic maps established for resistance genes Pm1, Pm6 and Pm7 employing amplified fragment length polymorphism (AFLP) markers indicated that these genes are independent of each other, supporting the results from monosomic analysis.

  18. Identification of Co-Segregating RAPD Marker Linked to Powdery Mildew Resistance Gene Pm 18 in Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-li; GU Feng; LI Tao; GAO Ju-rong; WANG Hong-gang

    2004-01-01

    The Pm18 gene of wheat confers resistance to the powdery mildew which is oneof the most serious diseases in many regions of the world. In this study, bulked segregant analysis (BSA) was used to develop randomly amplified polymorphic DNA (RAPD) markers linked to Pml8 gene. Three hundred and twenty decamer primers were screened and one of them was identified as RAPD marker (S411600) linked to Pml8. Using the F2 mapping population from the cross Pml8 × Chancellor, the marker S411600 was shown to co-segregate with the gene Pml8. This marker can be conveniently used for marker-assisted selection in wheat breeding programs for the identification or pyramiding of Pml8 with other resistance genes.

  19. Development of Random Amplified Polymorphism DNA Markers Linked to Powdery Mildew Resistance Gene in Melon

    Directory of Open Access Journals (Sweden)

    Budi Setiadi Daryono

    2015-11-01

    Full Text Available A random amplified polymorphic DNA (RAPD marker linked to powdery mildew resistance gene (Pm-I in melon PI 371795 was reported. However, the RAPD marker has problem in scoring. To detect powdery mildew resistance gene (Pm-I in melon accurately, the RAPD marker was cloned and sequenced to design sequence characterized amplified region (SCAR markers. SCAPMAR5 marker derived from pUBC411 primer yielded a single DNA band at 1061 bp. Segregation of SCAPMAR5 marker in bulk of F2 plants demonstrated that the marker was co-segregated with RAPD marker from which the SCAR marker was originated. Moreover, results of SCAR analysis in diverse melons showed SCAPMAR5 primers obtained a single 1061 bp linked to Pm-I in resistant melon PI 371795 and PMAR5. On the other hand, SCAPMAR5 failed to detect Pm-I in susceptible melons. Results of this study revealed that SCAR analysis not only confirmed melons that had been clearly scored for resistance to Pm-I evaluated by RAPD markers, but also clarified the ambiguous resistance results obtained by the RAPD markers.   Key words: Cucumis melo L., Pm-I, RAPD, SCAPMAR5

  20. Essential oils and whole milk in the control of soybean powdery mildew

    Directory of Open Access Journals (Sweden)

    Fabiano José Perina

    2013-11-01

    Full Text Available This research aimed to evaluate the potential of essential oils (EOs and cow's whole milk (CWM in order to control soybean powdery mildew and to estimate the most effective concentrations of these natural products in reducing the disease severity on soybean plants. Three experiments were carried out: The first experiment evaluated and selected the most effective treatments to reduce the severity of soybean powdery mildew under greenhouse conditions; the second experiment evaluated the effect of CWM and EOs of citronella, lemongrass, eucalyptus, cinnamon and tea tree on the pathogen through the ultrastructure analysis of soybean leaflets infected by Erysiphe diffusa using the scanning electron microscope (SEM and light microscope (LM technology. In the third experiment, the most effective products were tested at several concentrations in order to define the most effective concentrations to reduce disease severity under greenhouse conditions. The treatments CWM (100mL L-1 and EOs of citronella, lemongrass and eucalyptus (1.0mL L-1, reduced the disease severity from 67 to 74%. Direct effects from all natural products tested on the structures of E. diffusa were demonstrated through the SEM and LM analysis. Concentrations at 1.5mL L-1 for EOs of citronella, lemongrass and eucalyptus and also at 180mL L-1 for the treatment CWM were the most effective against E. diffusa on soybean.

  1. Application of Osthol Induces a Resistance Response Against Powdery Mildew in Pumpkin Leave

    Directory of Open Access Journals (Sweden)

    Yong Jian Fan

    2007-09-01

    Full Text Available Plants can defend themselves against fungal infection by natural means inducedby biotic and abiotic elicitors. Osthol is a natural compound extracted from dried fruits ofCnidii Monnieri Fructus. In this study, it has been shown to not only be a fungicide withacceptable curative properties (control efficacy of 68.72, but it also showed a significantprophylactic effect (with control efficacy of 77.36 against pumpkin powdery mildew at aconcentration of 100 μg·mL-1. In pumpkin leaves with/or without inoculation ofSphaerotheca fuliginea, osthol treatment induced the accumulation of chitinase andperoxidase and enhanced the transcription of chitinase gene in non-inoculated leaves. Thepotentiation of phenylalanine amonia-lyase activity in leaves by osthol application andfollowing inoculation was absent in that with inoculation or osthol treatment, indicatingthat induced PAL in osthol-pretreated plants was inoculation-mediated. In conclusion, thisnatural compound could induce resistance response in the plant against powdery mildew.

  2. Uncinula necator (Schow Burr., the Causal Agent of Grape Powdery Mildew: Economic Impact, Epidemiology and Control

    Directory of Open Access Journals (Sweden)

    Zoran Miladinović

    2007-01-01

    Full Text Available The article is an overview of what we know at present about the patogen Uncinula necator and the disease powdery mildew of grapevine, i.e. its economic status, inoculum source, microclimate conditions, vine susceptibility and principles of its protection.Powdery mildew is a major grapevine disease in terms of losses. It infects the plant’s green parts, reducing its fertility, spoiling the quality of grapes and wine and ruining plant vitality. The process additionally affects subsequent vegetation seasons. The disease occursevery year and its intensity depends on a number of factors.It had long been assumed that overwintering mycelium was the primary source of inoculum. More recent research, however, has revealed a crucial role of cleistothecia in many vineyards. They were found in our vine-growing regions long ago but their true role in the epidemiology of disease has been explained only recently.Microclimate conditions considerably affect the abundance and vitality of cleistothecia and the pathogen’s infection potential. Outbreaks and intensity of disease both depend on them, while vine susceptibility plays another important role, depending on cultivarand plant ontogenesis. Grapevine is most sensitive during flowering and bunch formation when conditions are generally good for the disease to appear and spread.Temperature, precipitation and relative air humidity may limit the occurrence of powdery mildew, but extreme values in that respect are a rarity. Their normal scope is more or less favourable for the disease, especially in Podgorica vineyards.Knowing the pathogen, especially its infection potential, environmental conditions, dynamics of host development and timely and good quality protection of vines, both preventive and chemical, is crucial for grapevine protection.Prevention is important but treatments with fungicides are crucial for U. necator control, and they can either focus on destroying the inoculum and delaying mildew outbreaks

  3. Genome-Wide Study of the Tomato SlMLO Gene Family and Its Functional Characterization in Response to the Powdery Mildew Fungus Oidium neolycopersici.

    Science.gov (United States)

    Zheng, Zheng; Appiano, Michela; Pavan, Stefano; Bracuto, Valentina; Ricciardi, Luigi; Visser, Richard G F; Wolters, Anne-Marie A; Bai, Yuling

    2016-01-01

    The MLO (Mildew Locus O) gene family encodes plant-specific proteins containing seven transmembrane domains and likely acting in signal transduction in a calcium and calmodulin dependent manner. Some members of the MLO family are susceptibility factors toward fungi causing the powdery mildew disease. In tomato, for example, the loss-of-function of the MLO gene SlMLO1 leads to a particular form of powdery mildew resistance, called ol-2, which arrests almost completely fungal penetration. This type of penetration resistance is characterized by the apposition of papillae at the sites of plant-pathogen interaction. Other MLO homologs in Arabidopsis regulate root response to mechanical stimuli (AtMLO4 and AtMLO11) and pollen tube reception by the female gametophyte (AtMLO7). However, the role of most MLO genes remains unknown. In this work, we provide a genome-wide study of the tomato SlMLO gene family. Besides SlMLO1, other 15 SlMLO homologs were identified and characterized with respect to their structure, genomic organization, phylogenetic relationship, and expression profile. In addition, by analysis of transgenic plants, we demonstrated that simultaneous silencing of SlMLO1 and two of its closely related homologs, SlMLO5 and SlMLO8, confer higher level of resistance than the one associated with the ol-2 mutation. The outcome of this study provides evidence for functional redundancy among tomato homolog genes involved in powdery mildew susceptibility. Moreover, we developed a series of transgenic lines silenced for individual SlMLO homologs, which lay the foundation for further investigations aimed at assigning new biological functions to the MLO gene family.

  4. Inheritance of Powdery Mildew Resistance in Cucumber (Cucumis sativus L.) and Development of an AFLP Marker for Resistance Detection

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cucumber powdery mildew is one of the most destructive diseases of cucumber throughout the world. In the present study, inheritance of powdery mildew resistance in three crosses, and linkage of resistance with amplified fragment length polymorphism (AFLP) markers are studied to formulate efficient strategies for breeding cultivars resistant to powdery mildew. The joint analysis of multiple generations and AFLP technique has been applied in this study. The best model is the one with two major genes, additive, dominant, and epistatic effects, plus polygenes with additive, dominant, and epistatic effects (E-1-0 model). The heritabilities of the major genes varied from 64.26% to 97.82%, and susceptibility was incompletely dominant for the two major genes in the three crosses studied. The additive effects of the two major genes and the dominant effect of the second major gene were high, and the epistatic effect of the additive-dominant between the two major genes was the highest in cross Ⅰ. In cross Ⅱ, the absolute value of the additive effect, dominant effect, and potential ratio of the first major gene were far higher than those of the second major gene, and the epistatic effect of the additive-additive was the highest. The genetic parameters of the two major genes in cross Ⅲ were similar to those in cross Ⅱ. Correlation and regression analyses showed that marker E25/M63-103 was linked to a susceptible gene controlling powdery mildew resistance. The marker could account for 19.98% of the phenotypic variation. When the marker was tested on a diverse set of 29 cucumber lines, the correlation between phenotype and genotype was not significant, which suggested cultivar specialty of gene expression or different methods of resistance to powdery mildew. The target DNA fragment was 103 bp in length, and only a small part was found to be homologous to DNA in the other species evaluated,which indicated that it was unique to the cucumber genome.

  5. Identification of QTL for adult-plant resistance to powdery mildew in Chinese wheat landrace Pingyuan 50

    Institute of Scientific and Technical Information of China (English)

    Muhammad; Azeem; Asad; Bin; Bai; Caixia; Lan; Jun; Yan; Xianchun; Xia; Yong; Zhang; Zhonghu; He

    2014-01-01

    Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance(APR)to powdery mildew in the field for over 60 years. To dissect the genetic basis of APR to powdery mildew in this cultivar, a mapping population of 137 double haploid(DH) lines derived from Pingyuan 50/Mingxian 169 was evaluated in replicated field trials for two years in Beijing(2009–2010 and 2010–2011) and one year in Anyang(2009–2010). A total of 540 polymorphic SSR markers were genotyped on the entire population for construction of a linkage map and QTL analysis. Three QTL were mapped on chromosomes 2BS(QPm.caas-2BS.2), 3BS(QPm.caas-3BS),and 5AL(QPm.caas-5AL) with the resistance alleles contributed by Pingyuan 50 explaining 5.3%,10.2%, and 9.1% of the phenotypic variances, respectively, and one QTL on chromosome 3BL(QPm.caas-3BL) derived from Mingxian 169 accounting for 18.1% of the phenotypic variance.QPm.caas-3BS, QPm.caas-3BL, and QPm.caas-5AL appear to be new powdery mildew APR loci.QPm.caas-2BS.2 and QPm.caas-5AL are possibly pleiotropic or closely linked resistance loci to stripe rust resistance QTL. Pingyuan 50 could be a potential genetic resource to facilitate breeding for improved APR to both powdery mildew and stripe rust.

  6. Identification of QTL for adult-plant resistance to powdery mildew in Chinese wheat landrace Pingyuan 50

    Directory of Open Access Journals (Sweden)

    Muhammad Azeem Asad

    2014-10-01

    Full Text Available Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance (APR to powdery mildew in the field for over 60 years. To dissect the genetic basis of APR to powdery mildew in this cultivar, a mapping population of 137 double haploid (DH lines derived from Pingyuan 50/Mingxian 169 was evaluated in replicated field trials for two years in Beijing (2009–2010 and 2010–2011 and one year in Anyang (2009–2010. A total of 540 polymorphic SSR markers were genotyped on the entire population for construction of a linkage map and QTL analysis. Three QTL were mapped on chromosomes 2BS (QPm.caas-2BS.2, 3BS (QPm.caas-3BS, and 5AL (QPm.caas-5AL with the resistance alleles contributed by Pingyuan 50 explaining 5.3%, 10.2%, and 9.1% of the phenotypic variances, respectively, and one QTL on chromosome 3BL (QPm.caas-3BL derived from Mingxian 169 accounting for 18.1% of the phenotypic variance. QPm.caas-3BS, QPm.caas-3BL, and QPm.caas-5AL appear to be new powdery mildew APR loci. QPm.caas-2BS.2 and QPm.caas-5AL are possibly pleiotropic or closely linked resistance loci to stripe rust resistance QTL. Pingyuan 50 could be a potential genetic resource to facilitate breeding for improved APR to both powdery mildew and stripe rust.

  7. Fine physical and genetic mapping of powdery mildew resistance gene MlIW172 originating from wild emmer (Triticum dicoccoides.

    Directory of Open Access Journals (Sweden)

    Shuhong Ouyang

    Full Text Available Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most important wheat diseases in the world. In this study, a single dominant powdery mildew resistance gene MlIW172 was identified in the IW172 wild emmer accession and mapped to the distal region of chromosome arm 7AL (bin7AL-16-0.86-0.90 via molecular marker analysis. MlIW172 was closely linked with the RFLP probe Xpsr680-derived STS marker Xmag2185 and the EST markers BE405531 and BE637476. This suggested that MlIW172 might be allelic to the Pm1 locus or a new locus closely linked to Pm1. By screening genomic BAC library of durum wheat cv. Langdon and 7AL-specific BAC library of hexaploid wheat cv. Chinese Spring, and after analyzing genome scaffolds of Triticum urartu containing the marker sequences, additional markers were developed to construct a fine genetic linkage map on the MlIW172 locus region and to delineate the resistance gene within a 0.48 cM interval. Comparative genetics analyses using ESTs and RFLP probe sequences flanking the MlIW172 region against other grass species revealed a general co-linearity in this region with the orthologous genomic regions of rice chromosome 6, Brachypodium chromosome 1, and sorghum chromosome 10. However, orthologous resistance gene-like RGA sequences were only present in wheat and Brachypodium. The BAC contigs and sequence scaffolds that we have developed provide a framework for the physical mapping and map-based cloning of MlIW172.

  8. Resistance to powdery mildew in the pea cultivar Xucai 1 is conferred by the gene er1

    Institute of Scientific and Technical Information of China (English)

    Suli Sun; Zhongyi Wang; Haining Fu; Canxing Duan; Xiaoming Wang; Zhendong Zhu

    2015-01-01

    Powdery mildew, caused by Erysiphe pisi D.C., is a major constraint to pea production worldwide. The pea cultivar Xucai 1 has shown high resistance to E. pisi under greenhouse and field conditions. The objectives of this study were to identify and characterize genes conferring resistance to powdery mildew in Xucai 1. Three crosses, Qizhen 76 × Xucai 1,Bawan 6 × Xucai 1, and Xucai 1 × Bawan 6, were made to generate populations for genetic analysis. The resistance to E. pisi and segregation ratios in the F1, F2, and F2:3populations suggested a single recessive gene conferring the resistance of Xucai 1. Bulked segregant analysis was used to map the resistance gene using two F2 populations. The resistance gene was close to markers AD60 and c5 DNAmet on linkage group VI with genetic distances of9.9 c M and 15.4 c M in the Xucai 1 × Bawan 6 F2 population and 8.7 c M and 8.1 c M in the Qizhen 76 × Xucai 1 F2 population, respectively, suggesting that the resistance gene was an er1 allele. This hypothesis was confirmed by comparison of the c DNA sequences of the Ps MLO1 gene between the parents and the Ps MLO1 wild type. Three distinct types of transcripts in Xucai 1, characterized by a 129-bp deletion and 155- and 220-bp insertions,were detected, consistent with the structure of the er1-2 allele. We concluded that resistance in Xucai 1 was conferred by er1-2 and that its linked markers will be useful in pea breeding programs.

  9. Suppression of edr2-mediated powdery mildew resistance, cell death and ethylene-induced senescence by mutations in ALD1 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Haozhen Nie; Yingying Wu; Chunpeng Yao; Dingzhong Tang

    2011-01-01

    EDR2 is a negative regulator of the defense response and cell death in Arabidopsis. Loss-of-function of EDR2 leads to enhanced resistance to powdery mildew. To identify new components in the EDR2 signal transduction pathway, mutations that suppress edr2 resistant phenotypes were screened. Three mutants, edts5-1, edts5-2 and edts5-3 (edr (t)wo (s)uppressor 5), were identified. The EDTS5 gene was identified by map-based cloning and previously was shown to encode an aminotransferase (ALD1). Therefore we renamed these three alleles ald1-10, ald1-11 and ald1-12, respectively. Mutations in ALD1 suppressed all edr2-mediated phenotypes, including powdery mildew resistance, programmed cell death and ethylene-induced senescence. Accumulation of hydrogen peroxide in edr2 was also suppressed by ald1 mutation. The expression of defense-related genes was up-regulated in the edr2 mutant, and the up-regulation of those genes in edr2 was suppressed in the edr2/ald1 double mutant. The ald1 single mutant displayed delayed ethylene-induced senescence. In addition, ald1 mutation suppressed edr1-mediated powdery mildew resistance, but could not suppress the edr1/edr2 double-mutant phenotype. These data demonstrate that ALD1 plays important roles in edr2-mediated defense responses and senescence, and revealed a crosstalk between ethylene and salicylic acid signaling mediated by ALD1 and EDR2.

  10. Messages from Powdery Mildew DNA:How the Interplay with a Host Moulds Pathogen Genomes

    Institute of Scientific and Technical Information of China (English)

    Pietro D. Spanu

    2014-01-01

    The genomes of the barley,Arabidopsis and pea powdery mildew are signiifcantly larger than those of related fungi. This is due to an extraordinary expansion of retro-trasposons that are evident as repetitive elements in the sequence. The protein coding genes are fewer than expected due to an overall reduction in the size of gene families, a reduction in the number of paralogs and because of the loss of certain metabolic pathways. Many of these changes have also been observed in the genomes of other taxonomically unrelated obligate biotrophic pathogens. The only group of genes that bucks the trend of gene loss, are those encoding small secreted proteins that bear the hall marks of effectors.

  11. Effects of elevated CO2 and temperature on interactions of zucchini and powdery mildew

    Directory of Open Access Journals (Sweden)

    Massimo PUGLIESE

    2013-01-01

    Full Text Available Effects of increased CO2 and temperature on powdery mildew (Podosphaera xanthii of zucchini (Cucurbita pepo, were evaluated under controlled conditions. Zucchini plants were grown in phytotrons under four different simulated climatic conditions: 450 ppm of CO2 at standard (18°C night, 24°C day and elevated temperatures (22°C night, 28°C day, elevated CO2 (800 ppm with standard temperature and elevated CO2 (800 ppm with elevated temperature (4°C higher than standard. Physiological responses of zucchini and pathogen development were studied. Under elevated CO2 both healthy and infected zucchini plants grew better when temperature was lower. Elevated CO2 generally caused no significant differences in pathogen development or disease severity, whereas elevated temperature stimulated the development of the pathogen. A combination of elevated CO2 and temperature always stimulated the development of the pathogen and disease severity compared to standard conditions.

  12. Rye Pm8 and wheat Pm3 are orthologous genes and show evolutionary conservation of resistance function against powdery mildew.

    Science.gov (United States)

    Hurni, Severine; Brunner, Susanne; Buchmann, Gabriele; Herren, Gerhard; Jordan, Tina; Krukowski, Patricia; Wicker, Thomas; Yahiaoui, Nabila; Mago, Rohit; Keller, Beat

    2013-12-01

    The improvement of wheat through breeding has relied strongly on the use of genetic material from related wild and domesticated grass species. The 1RS chromosome arm from rye was introgressed into wheat and crossed into many wheat lines, as it improves yield and fungal disease resistance. Pm8 is a powdery mildew resistance gene on 1RS which, after widespread agricultural cultivation, is now widely overcome by adapted mildew races. Here we show by homology-based cloning and subsequent physical and genetic mapping that Pm8 is the rye orthologue of the Pm3 allelic series of mildew resistance genes in wheat. The cloned gene was functionally validated as Pm8 by transient, single-cell expression analysis and stable transformation. Sequence analysis revealed a complex mosaic of ancient haplotypes among Pm3- and Pm8-like genes from different members of the Triticeae. These results show that the two genes have evolved independently after the divergence of the species 7.5 million years ago and kept their function in mildew resistance. During this long time span the co-evolving pathogens have not overcome these genes, which is in strong contrast to the breakdown of Pm8 resistance since its introduction into commercial wheat 70 years ago. Sequence comparison revealed that evolutionary pressure acted on the same subdomains and sequence features of the two orthologous genes. This suggests that they recognize directly or indirectly the same pathogen effectors that have been conserved in the powdery mildews of wheat and rye.

  13. Powdery Mildew Decreases the Radial Growth of Oak Trees with Cumulative and Delayed Effects over Years

    Science.gov (United States)

    Bert, Didier; Lasnier, Jean-Baptiste; Capdevielle, Xavier; Dugravot, Aline; Desprez-Loustau, Marie-Laure

    2016-01-01

    Quercus robur and Q. petraea are major European forest tree species. They have been affected by powdery mildew caused by Erysiphe alphitoides for more than a century. This fungus is a biotrophic foliar pathogen that diverts photosynthetate from the plant for its own nutrition. We used a dendrochronological approach to investigate the effects of different levels of infection severity on the radial growth of young oak trees. Oak infection was monitored at individual tree level, at two sites in southwestern France, over a five-year period (2001–2005). Mean infection severity was almost 75% (infected leaf area) at the end of the 2001 growing season, at both sites, but only about 40% in 2002, and 8%, 5% and 2% in 2003, 2004 and 2005, respectively. Infection levels varied considerably between trees and were positively related between 2001 and 2002. Increment cores were taken from each tree to assess annual ring widths and increases in basal area. Annual radial growth was standardised to take the effect of tree size into account. Annual standardised radial growth was significantly and negatively correlated with infection severity in the same year, for both 2001 and 2002, and at both sites. The decrease in growth reached 70–90% for highly infected trees. The earlywood width was poorly correlated with infection severity, but the proportion of latewood in tree rings was lower in highly infected trees (60%) than in less heavily infected trees (85%). Infection in 2001 and 2002 was found to have a cumulative effect on radial growth in these years, together with a delayed effect detectable in 2003. Thus, even non-lethal pathogens like powdery mildew can have a significant impact on tree functioning. This impact should be taken into account in growth and yield models, to improve predictions of forest net primary production. PMID:27177029

  14. Phylogeography and population structure of the grape powdery mildew fungus, Erysiphe necator, from diverse Vitis species

    Directory of Open Access Journals (Sweden)

    Brewer Marin

    2010-09-01

    Full Text Available Abstract Background The grape powdery mildew fungus, Erysiphe necator, was introduced into Europe more than 160 years ago and is now distributed everywhere that grapes are grown. To understand the invasion history of this pathogen we investigated the evolutionary relationships between introduced populations of Europe, Australia and the western United States (US and populations in the eastern US, where E. necator is thought to be native. Additionally, we tested the hypothesis that populations of E. necator in the eastern US are structured based on geography and Vitis host species. Results We sequenced three nuclear gene regions covering 1803 nucleotides from 146 isolates of E. necator collected from the eastern US, Europe, Australia, and the western US. Phylogeographic analyses show that the two genetic groups in Europe represent two separate introductions and that the genetic groups may be derived from eastern US ancestors. Populations from the western US and Europe share haplotypes, suggesting that the western US population was introduced from Europe. Populations in Australia are derived from European populations. Haplotype richness and nucleotide diversity were significantly greater in the eastern US populations than in the introduced populations. Populations within the eastern US are geographically differentiated; however, no structure was detected with respect to host habitat (i.e., wild or cultivated. Populations from muscadine grapes, V. rotundifolia, are genetically distinct from populations from other Vitis host species, yet no differentiation was detected among populations from other Vitis species. Conclusions Multilocus sequencing analysis of the grape powdery mildew fungus is consistent with the hypothesis that populations in Europe, Australia and the western US are derived from two separate introductions and their ancestors were likely from native populations in the eastern US. The invasion history of E. necator follows a pattern

  15. Powdery Mildew Decreases the Radial Growth of Oak Trees with Cumulative and Delayed Effects over Years.

    Directory of Open Access Journals (Sweden)

    Didier Bert

    Full Text Available Quercus robur and Q. petraea are major European forest tree species. They have been affected by powdery mildew caused by Erysiphe alphitoides for more than a century. This fungus is a biotrophic foliar pathogen that diverts photosynthetate from the plant for its own nutrition. We used a dendrochronological approach to investigate the effects of different levels of infection severity on the radial growth of young oak trees. Oak infection was monitored at individual tree level, at two sites in southwestern France, over a five-year period (2001-2005. Mean infection severity was almost 75% (infected leaf area at the end of the 2001 growing season, at both sites, but only about 40% in 2002, and 8%, 5% and 2% in 2003, 2004 and 2005, respectively. Infection levels varied considerably between trees and were positively related between 2001 and 2002. Increment cores were taken from each tree to assess annual ring widths and increases in basal area. Annual radial growth was standardised to take the effect of tree size into account. Annual standardised radial growth was significantly and negatively correlated with infection severity in the same year, for both 2001 and 2002, and at both sites. The decrease in growth reached 70-90% for highly infected trees. The earlywood width was poorly correlated with infection severity, but the proportion of latewood in tree rings was lower in highly infected trees (60% than in less heavily infected trees (85%. Infection in 2001 and 2002 was found to have a cumulative effect on radial growth in these years, together with a delayed effect detectable in 2003. Thus, even non-lethal pathogens like powdery mildew can have a significant impact on tree functioning. This impact should be taken into account in growth and yield models, to improve predictions of forest net primary production.

  16. Molecular mapping of powdery mildew resistance gene Eg-3 in cultivated oat (Avena sativa L. cv. Rollo).

    Science.gov (United States)

    Mohler, Volker; Zeller, Friedrich J; Hsam, Sai L K

    2012-05-01

    Powdery mildew is a prevalent fungal disease affecting oat (Avena sativa L.) production in Europe. Common oat cultivar Rollo was previously shown to carry the powdery mildew resistance gene Eg-3 in common with cultivar Mostyn. The resistance gene was mapped with restriction fragment length polymorphism (RFLP) markers from Triticeae group-1 chromosomes using a population of F(3) lines from a cross between A. byzantina cv. Kanota and A. sativa cv. Rollo. This comparative mapping approach positioned Eg-3 between cDNA-RFLP marker loci cmwg706 and cmwg733. Since both marker loci were derived from the long arm of barley chromosome 1H, the subchromosomal location of Eg-3 was assumed to be on the long arm of oat chromosome 17. Amplified fragment length polymorphism (AFLP) marker technology featured as an efficient means for obtaining markers closely linked to Eg-3.

  17. 平榛白粉病药剂防治试验%Corylus heterophylla Powdery Mildew Test

    Institute of Scientific and Technical Information of China (English)

    王尧; 孙冬伟

    2012-01-01

      Powdery mildew is an important disease with hazelnut ,rapid onset ,spread fast ,serious harm characteristics of .The hazelnut powdery mildew testing found ,Corylus heterophylla pow-dery mildew in Fushun city starting period for June to early July ,flourishing period in the middle of July to late September ,stage of 10 month to month l1 .Effect of chemical control of powdery mildew of Corylus heterophylla effective best is 12 .5% myclobutanil 1000 times liquid ,use 7 days later to investigate its control effect reached 57 .6% ,45% and 15% 200 times solution LSSS three Triadimefon 400 times fluid control effect were 51 .2% ,51 .7% .%  白粉病是榛子的重要病害,具有发病快、传播快、危害严重的特点.通过对平榛白粉病药剂防治试验发现,平榛白粉病在抚顺市始发期为6月上旬至7月上旬,盛发期为7月中旬至9月下旬,末期为10月上旬至11月.平榛白粉病有效药剂防治效果最好的是12.5%腈菌唑1000倍液,施用7天后调查其防治效果达到57.6%,45%石硫合剂200倍液和15%三唑酮400倍液防治效果分别为51.2%、51.7%.

  18. The Podosphaera fusca TUB2 gene, a molecular "Swiss Army knife" with multiple applications in powdery mildew research.

    Science.gov (United States)

    Vela-Corcía, David; Bellón-Gómez, Davinia; López-Ruiz, Francisco; Torés, Juan Antonio; Pérez-García, Alejandro

    2014-02-01

    The powdery mildew fungus Podosphaera fusca (synonym Podosphaera xanthii) is the main causal agent of cucurbit powdery mildew and one of the most important limiting factors for cucurbit production worldwide. Despite the fungus' economic importance, very little is known about the physiological and molecular processes involved in P. fusca biology and pathogenesis. In this study, we isolated and characterised the β-tubulin-encoding gene of P. fusca (PfTUB2) to develop molecular tools with different applications in powdery mildew research. PfTUB2 is predicted to encode a protein of 447 amino acid residues. The coding region is interrupted by six introns that occur at approximately the same positions as the introns present in other fungal TUB2-like genes. Once cloned, the PfTUB2 sequence information was used in different applications. Our results showed that the TUB2 gene is a good marker for molecular phylogenetics in powdery mildew fungi but it is unsuitable for the analysis of intraspecific diversity in P. fusca. The expression of PfTUB2 was proven to be stable in different temperature conditions, supporting its use as a reference gene in quantitative gene expression studies. Furthermore, an allele-specific PCR assay for the detection of resistance to methyl-2-benzimidazole carbamate (MBC) fungicides in P. fusca was developed based on the correlation between the single amino acid change E198A in β-tubulin and the MBC resistance phenotype. Lastly, PfTUB2 was used as a target gene in the development of a high-throughput method to quantify fungal growth in plant tissues.

  19. Allocation of the S-genome chromosomes of Aegilops variabilis Eig. carrying powdery mildew resistance in triticale (× Triticosecale Wittmack).

    Science.gov (United States)

    Kwiatek, M; Belter, J; Majka, M; Wiśniewska, H

    2016-03-01

    It has been hypothesized that the powdery mildew adult plant resistance (APR) controlled by the Pm13 gene in Aegilops longissima Schweinf. & Muschl. (S(l)S(l)) has been evolutionary transferred to Aegilops variabilis Eig. (UUSS). The molecular marker analysis and the visual evaluation of powdery mildew symptoms in Ae. variabilis and the Ae. variabilis × Secale cereale amphiploid forms (2n = 6x = 42, UUSSRR) showed the presence of product that corresponded to Pm13 marker and the lower infection level compared to susceptible model, respectively. This study also describes the transfer of Ae. variabilis Eig. (2n = 4x = 28, U(v)U(v)S(v)S(v)) chromosomes, carrying powdery mildew resistance, into triticale (× Triticosecale Wittm., 2n = 6x = 42, AABBRR) using Ae. variabilis × S. cereale amphiploid forms. The individual chromosomes of Ae. variabilis, triticale 'Lamberto' and hybrids were characterized by genomic and fluorescence in situ hybridization (GISH/FISH). The chromosome configurations of obtained hybrid forms were studied at first metaphase of meiosis of pollen mother cells (PMCs) using GISH. The statistical analysis showed that the way of S-genome chromosome pairing and transmission to subsequent hybrid generations was diploid-like and had no influence on chromosome pairing of triticale chromosomes. The cytogenetic study of hybrid forms were supported by the marker-assisted selection using Pm13 marker and visual evaluation of natural infection by Blumeria graminis, that allowed to select the addition or substitution lines of hybrids carrying chromosome 3S(v) which were tolerant to the powdery mildew infection.

  20. A complex protein derivative acts as biogenic elicitor of grapevine resistance against powdery mildew under field conditions.

    Science.gov (United States)

    Nesler, Andrea; Perazzolli, Michele; Puopolo, Gerardo; Giovannini, Oscar; Elad, Yigal; Pertot, Ilaria

    2015-01-01

    Powdery mildew caused by Erysiphe necator is one of the most important grapevine diseases in several viticulture areas, and high fungicide input is required to control it. However, numerous synthetic chemical pesticides are under scrutiny due to concerns about their impact on human health and the environment. Biopesticides, such as biogenic elicitors, are a promising alternative to chemical fungicides. Although several studies have reported on effective elicitors against grapevine diseases, their efficacy under field conditions has not been investigated extensively or has occurred at rather limited levels. Our goal was to examine the efficacy of a protein-based composition, namely nutrient broth (NB), against powdery mildew under field conditions and to characterize its mechanism of action. Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures. The level of disease control achieved with NB was comparable to standard fungicide treatments both on leaves and bunches across three different years. NB has no direct toxic effect on the germination of E. necator conidia, and it activates plant resistance with both systemic and translaminar effect in experiments with artificial inoculation under controlled conditions. NB induced the expression of defense-related genes in grapevine, demonstrating stimulation of plant defense mechanisms, prior to and in the early stages of pathogen infection. NB is a natural derivative from meat and yeast, substances that tend not to raise concerns about toxicological and ecotoxicological properties. NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

  1. Studies in plant pathogenic fungi—II. On some powdery mildews (Erysiphales) recently recorded from the Netherlands

    OpenAIRE

    Noordeloos, M.E.; Loerakker, W.M.

    1989-01-01

    Full descriptions and notes on their pathogenous properties are given of the anamorphs of four powdery mildews recently recorded as new from the Netherlands. Two are described as new species, viz. Oidium longipes on Solarium melongena and O. limnanthis on Limnanthes alba. Oidium lycopersicum Cooke & Massee is redescribed on account of the study of the holotype and recently collected material, and an Oidium sp. occurring on Chrysanthemum morifolium is critically compared with the existing desc...

  2. A complex protein derivative acts as biogenic elicitor of grapevine resistance against powdery mildew under field conditions

    Directory of Open Access Journals (Sweden)

    Andrea eNesler

    2015-09-01

    Full Text Available Powdery mildew caused by Erysiphe necator is one of the most important grapevine diseases in several viticulture areas, and high fungicide input is required to control it. However, numerous synthetic chemical pesticides are under scrutiny due to concerns about their impact on human health and the environment. Biopesticides, such as biogenic elicitors, are a promising alternative to chemical fungicides. Although several studies have reported on effective elicitors against grapevine diseases, their efficacy under field conditions has not been investigated extensively or has occurred at rather limited levels. Our goal was to examine the efficacy of a protein-based composition, namely nutrient broth (NB, against powdery mildew under field conditions and to characterize its mechanism of action. Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures. The level of disease control achieved with NB was comparable to standard fungicide treatments both on leaves and bunches across three different years. NB has no direct toxic effect on the germination of E. necator conidia, and it activates plant resistance with both systemic and translaminar effect in experiments with artificial inoculation under controlled conditions. NB induced the expression of defense-related genes in grapevine, demonstrating stimulation of plant defense mechanisms, prior to and in the early stages of pathogen infection. NB is a natural derivative from meat and yeast, substances that tend not to raise concerns about toxicological and ecotoxicological properties. NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

  3. Lagged association between powdery mildew leaf severity, airborne inoculum, weather, and crop losses in strawberry.

    Science.gov (United States)

    Carisse, O; Morissette-Thomas, V; Van der Heyden, H

    2013-08-01

    used to construct the model (r = 0.99 and 0.90) and of independent data (r = 0.92). For the 12 epidemics studied, 5% crop loss was reached when an average of 17% leaf area diseased was observed since the beginning of symptom development. These results indicate that information on foliar powdery mildew must be considered when making strawberry powdery mildew management decisions.

  4. Gene expression profiling related to powdery mildew resistance in wheat with the method of suppression subtractive hybridization

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    "Bainong 3217×Mardler" BC5F4 wheat line at the initial stage of inoculation with powdery mildew pathogen (Erysiphe graminis DC) was used to construct a suppression subtractive hybridization (SSH) cDNA library. Totally 760 ESTs were obtained through sequencing. Similarity analysis of ESTs based on BLASTn and BLASTx with the sequences in GenBank, in combination with macroarray differential screening, revealed that 199 ESTs of 65 kinds were known to be functionally disease resistance related. Based on the gene expression profiling in the present study, it is postulated that salicylic acid (SA) and MAP-related signal transduction pathways were involved in powdery mildew resistance in wheat. System acquired resistance genes were predominant in terms of kinds and quantity. With the initiation of cell defense reaction, the genes conferring anti-oxida- tion substances were largely expressed and thus cell protection mechanism was activated. Much evidence revealed that phenylpropanes metabolic pathway was involved in phytoalexin synthesis in wheat powdery mildew resistance. Genes conferring some enzymes of structural modification of cell walls and proteinase inhibitors inhibiting pathogen growth were also detected. The genes controlling a few proteinases (mainly cysteine proteinase) had a considerable redundancy of expression.

  5. Daily light integral and day light quality: Potentials and pitfalls of nighttime UV treatments on cucumber powdery mildew.

    Science.gov (United States)

    Suthaparan, Aruppillai; Solhaug, Knut Asbjørn; Stensvand, Arne; Gislerød, Hans Ragnar

    2017-10-01

    Nighttime ultraviolet (UV) radiation, if applied properly, has a significant potential for management of powdery mildews in many crop species. In this study, the role of growth light duration, irradiance, a combination of both (daily light integral) and light spectral quality (blue or red) on the efficacy of UV treatments against powdery mildew caused by Podosphaera xanthii and the growth performance of cucumber plants was studied in growth chambers. Increasing daily light integral provided by high-pressure sodium lamps (HPS) decreased efficacy of nighttime UV treatments against P. xanthii, but it increased plant growth. Furthermore, the efficacy of nighttime UV decreased when day length was increased from 16 to 20h at a constant daily light integral. The efficacy of nighttime UV increased if red light was applied after UV treatment, showing the possibility of day length extension without reducing the effect of UV. Increasing the dose of blue light during daytime reduced the efficacy of nighttime UV in controlling the disease, whereas blue deficient growth light (<6% of blue) caused UV mediated curling of young leaves. Furthermore, application of blue light after nighttime UV reduced its disease control efficacy. This showed the importance of maintaining a minimum of blue light in the growth light before nighttime UV treatment. Findings from this study showed that optimization of nighttime UV for management of powdery mildew is dependent on the spectral composition of the photosynthetically active radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. An LRR/Malectin Receptor-Like Kinase Mediates Resistance to Non-adapted and Adapted Powdery Mildew Fungi in Barley and Wheat.

    Science.gov (United States)

    Rajaraman, Jeyaraman; Douchkov, Dimitar; Hensel, Götz; Stefanato, Francesca L; Gordon, Anna; Ereful, Nelzo; Caldararu, Octav F; Petrescu, Andrei-Jose; Kumlehn, Jochen; Boyd, Lesley A; Schweizer, Patrick

    2016-01-01

    Pattern recognition receptors (PRRs) belonging to the multigene family of receptor-like kinases (RLKs) are the sensing devices of plants for microbe- or pathogen-associated molecular patterns released from microbial organisms. Here we describe Rnr8 (for Required for non-host resistance 8) encoding HvLEMK1, a LRR-malectin domain-containing transmembrane RLK that mediates non-host resistance of barley to the non-adapted wheat powdery mildew fungus Blumeria graminis f.sp. tritici. Transgenic barley lines with silenced HvLEMK1 allow entry and colony growth of the non-adapted pathogen, although sporulation was reduced and final colony size did not reach that of the adapted barley powdery mildew fungus B. graminis f.sp. hordei. Transient expression of the barley or wheat LEMK1 genes enhanced resistance in wheat to the adapted wheat powdery mildew fungus while expression of the same genes did not protect barley from attack by the barley powdery mildew fungus. The results suggest that HvLEMK1 is a factor mediating non-host resistance in barley and quantitative host resistance in wheat to the wheat powdery mildew fungus.

  7. An LRR/malectin receptor-like kinase mediates resistance to non-adapted and adapted powdery mildew fungi in barley and wheat

    Directory of Open Access Journals (Sweden)

    Jeyaraman Rajaraman

    2016-12-01

    Full Text Available Pattern recognition receptors (PRRs belonging to the multigene family of receptor-like kinases (RLKs are the sensing devices of plants for microbe- or pathogen-associated molecular patterns released from microbial organisms. Here we describe Rnr8 (for required for nonhost resistance 8 encoding HvLEMK1, a LRR-malectin domain-containing transmembrane RLK that mediates nonhost resistance of barley to the non-adapted wheat powdery mildew fungus Blumeria graminis f.sp. tritici. Transgenic barley lines with silenced HvLEMK1 allow entry and colony growth of the non-adapted pathogen, although sporulation was reduced and final colony size did not reach that of the adapted barley powdery mildew fungus Blumeria graminis f.sp. hordei. Transient expression of the barley or wheat LEMK1 genes enhanced resistance in wheat to the adapted wheat powdery mildew fungus while expression of the same genes did not protect barley from attack by the barley powdery mildew fungus. The results suggest that HvLEMK1 is a factor mediating nonhost resistance in barley and quantitative host resistance in wheat to the wheat powdery mildew fungus.

  8. Evaluation of wavelet spectral features in pathological detection and discrimination of yellow rust and powdery mildew in winter wheat with hyperspectral reflectance data

    Science.gov (United States)

    Shi, Yue; Huang, Wenjiang; Zhou, Xianfeng

    2017-04-01

    Hyperspectral absorption features are important indicators of characterizing plant biophysical variables for the automatic diagnosis of crop diseases. Continuous wavelet analysis has proven to be an advanced hyperspectral analysis technique for extracting absorption features; however, specific wavelet features (WFs) and their relationship with pathological characteristics induced by different infestations have rarely been summarized. The aim of this research is to determine the most sensitive WFs for identifying specific pathological lesions from yellow rust and powdery mildew in winter wheat, based on 314 hyperspectral samples measured in field experiments in China in 2002, 2003, 2005, and 2012. The resultant WFs could be used as proxies to capture the major spectral absorption features caused by infestation of yellow rust or powdery mildew. Multivariate regression analysis based on these WFs outperformed conventional spectral features in disease detection; meanwhile, a Fisher discrimination model exhibited considerable potential for generating separable clusters for each infestation. Optimal classification returned an overall accuracy of 91.9% with a Kappa of 0.89. This paper also emphasizes the WFs and their relationship with pathological characteristics in order to provide a foundation for the further application of this approach in monitoring winter wheat diseases at the regional scale.

  9. RUN1 and REN1 Pyramiding in Grapevine (Vitis vinifera cv. Crimson Seedless) Displays an Improved Defense Response Leading to Enhanced Resistance to Powdery Mildew (Erysiphe necator).

    Science.gov (United States)

    Agurto, Mario; Schlechter, Rudolf O; Armijo, Grace; Solano, Esteban; Serrano, Carolina; Contreras, Rodrigo A; Zúñiga, Gustavo E; Arce-Johnson, Patricio

    2017-01-01

    Fungal pathogens are the cause of the most common diseases in grapevine and among them powdery mildew represents a major focus for disease management. Different strategies for introgression of resistance in grapevine are currently undertaken in breeding programs. For example, introgression of several resistance genes (R) from different sources for making it more durable and also strengthening the plant defense response. Taking this into account, we cross-pollinated P09-105/34, a grapevine plant carrying both RUN1 and REN1 pyramided loci of resistance to Erysiphe necator inherited from a pseudo-backcrossing scheme with Muscadinia rotundifolia and Vitis vinifera 'Dzhandzhal Kara,' respectively, with the susceptible commercial table grape cv. 'Crimson Seedless.' We developed RUN1REN1 resistant genotypes through conventional breeding and identified them by marker assisted selection. The characterization of defense response showed a highly effective defense mechanism against powdery mildew in these plants. Our results reveal that RUN1REN1 grapevine plants display a robust defense response against E. necator, leading to unsuccessful fungal establishment with low penetration rate and poor hypha development. This resistance mechanism includes reactive oxygen species production, callose accumulation, programmed cell death induction and mainly VvSTS36 and VvPEN1 gene activation. RUN1REN1 plants have a great potential as new table grape cultivars with durable complete resistance to E. necator, and are valuable germplasm to be included in grape breeding programs to continue pyramiding with other sources of resistance to grapevine diseases.

  10. Quaternary IPM (integrated pest management)--concept for the control of powdery mildew in sugar beets.

    Science.gov (United States)

    Wolf, P F J; Verreet, A

    2008-01-01

    Powdery mildew, caused by Erysiphe betae (Vanha) Weltzien, may be assumed as an important leaf disease in sugar beet growing areas of central Europe. Although the causal agent is mainly adapted to arid climatic zones, the disease is appearing every year, where the extent of infection is mainly dependent on weather conditions and susceptibility of cultivar. The losses caused by powdery mildew seldom exceed 10% of sugar yield; moreover, losses are likely only under the condition that the epidemic onset occurs before end-August. Nevertheless, the epidemic onset varies in a wide range, as there are years with high incidence followed by growing periods without severe infection. Therefore, in order to have a flexible control of the disease, where the use of fungicides could be minimised to an essential amount, a quaternary IPM (Integrated Pest Management) -concept was developed. The development is based on epidemiological field studies (Germany, 1993-2004, n = 76) of sugar beet leaf diseases under variation of year, site and cultivar. Efficacy of fungicide treatment timing was assessed in relation to the epidemic development. Comparison of treatments comprised fungicide sprays carried out from disease initiation till later stages of the epidemic. Additionally, the assessments were performed in relation to an untreated and a healthy control--the latter was three times treated according to a treatment regime with three to four week intervals. The effect of different application timings was measured by the potential of disease and yield loss control. The quaternary concept combines the advantages of four elements in order to compensate the constraints of the single tools: The period without disease risk is determined by a so-called negative-prognosis (i). First symptoms appear in the period from mid-July till the beginning of September. If disease initiation cannot be excluded, field observations by a sample of 100 leaves are advised. The disease scores enable the appliance

  11. Genetic mapping of two genes conferring resistance to powdery mildew in common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Pérez-Vega, Elena; Trabanco, Noemí; Campa, Ana; Ferreira, Juan José

    2013-06-01

    Powdery mildew (PM) is a serious disease in many legume species, including the common bean (Phaseolus vulgaris L.). This study investigated the genetic control behind resistance reaction to PM in the bean genotype, Cornell 49242. The results revealed evidence supporting a qualitative mode of inheritance for resistance and the involvement of two independent genes in the resistance reaction. The location of these resistance genes was investigated in a linkage genetic map developed for the XC RIL population. Contingency tests revealed significant associations for 28 loci out of a total of 329 mapped loci. Fifteen were isolated or formed groups with less than two loci. The thirteen remaining loci were located at three regions in linkage groups Pv04, Pv09, and Pv11. The involvement of Pv09 was discarded due to the observed segregation in the subpopulation obtained from the Xana genotype for the loci located in this region. In contrast, the two subpopulations obtained from the Xana genotype for the BM161 locus, linked to the Co-3/9 anthracnose resistance gene (Pv04), and from the Xana genotype for the SCAReoli locus, linked to the Co-2 anthracnose resistance gene (Pv11), exhibited monogenic segregations, suggesting that both regions were involved in the genetic control of resistance. A genetic dissection was carried out to verify the involvement of both regions in the reaction to PM. Two resistant recombinant lines were selected, according to their genotypes, for the block of loci included in the Co-2 and Co-3/9 regions, and they were crossed with the susceptible parent, Xana. Linkage analysis in the respective F2 populations supported the hypothesis that a dominant gene (Pm1) was located in the linkage group Pv11 and another gene (Pm2) was located in the linkage group Pv04. This is the first report showing the localization of resistance genes against powdery mildew in Phaseolus vulgaris and the results offer the opportunity to increase the efficiency of breeding

  12. 亚麻种质对白粉病的抗性评价%Resistance Evaluation of Flax Varieties to Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    乔红霞; 陈娟

    2012-01-01

    The resistance evaluation of 53 flax varieties to powdery mildew in Qingyang region were conducted, the results showed that there were nearly no flax varieties with immune to powdery mildew, except for Xiji variety. There are very short of flax germplasm resources which are resistance to powdery mildew in Qingyang region.%对收集的53个亚麻种质进行了白粉病田间抗性评价,结果表明所调查的亚麻种质均无免疫(M)植株,仅西吉胡麻为抗(R)病品种,庆阳市抗白粉病亚麻资源材料较为匮乏.

  13. The novel gene VpPR4-1 from Vitis pseudoreticulata increases powdery mildew resistance in transgenic Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Lingmin eDai

    2016-05-01

    Full Text Available Pathogenesis-related proteins (PRs can lead to increased resistance of the whole plant to pathogen attack. Here, we isolate and characterize a PR-4 protein from a wild Chinese grape Vitis pseudoreticulata which shows greatly elevated transcription following powdery mildew infection. Its expression profiles under a number of abiotic stresses were also investigated. The PR-4 gene was overexpressed in regenerated V. vinifera cv. Red Globe via Agrobacterium tumefaciens-mediated transformation and verified by the Western blot. The transgenic grapevines exhibited higher expression levels of PR-4 protein content than wild-type vines and also repressed the growth of powdery mildew. The PR gene responds differently to different stresses in the PR-4 transformants. This study demonstrates that PR-4 protein in grapes plays a vital role in defense against powdery mildew invasion.

  14. Reconstitution of cyanogenesis in barley (Hordeum vulgare L.) and its implications for resistance against the barley powdery mildew fungus.

    Science.gov (United States)

    Nielsen, Kirsten A; Hrmova, Maria; Nielsen, Janni Nyvang; Forslund, Karin; Ebert, Stefan; Olsen, Carl E; Fincher, Geoffrey B; Møller, Birger Lindberg

    2006-04-01

    Barley (Hordeum vulgare L.) produces a leucine-derived cyanogenic beta-D-glucoside, epiheterodendrin that accumulates specifically in leaf epidermis. Barley leaves are not cyanogenic, i.e. they do not possess the ability to release hydrogen cyanide, because they lack a cyanide releasing beta-D-glucosidase. Cyanogenesis was reconstituted in barley leaf epidermal cells through single cell expression of a cDNA encoding dhurrinase-2, a cyanogenic beta-D-glucosidase from sorghum. This resulted in a 35-60% reduction in colonization rate by an obligate parasite Blumeria graminis f. sp. hordei, the causal agent of barley powdery mildew. A database search for barley homologues of dhurrinase-2 identified a (1,4)-beta-D-glucan exohydrolase isozyme betaII that is located in the starchy endosperm of barley grain. The purified barley (1,4)-beta-D-glucan exohydrolase isozyme betaII was found to hydrolyze the cyanogenic beta-D-glucosides, epiheterodendrin and dhurrin. Molecular modelling of its active site based on the crystal structure of linamarase from white clover, demonstrated that the disposition of the catalytic active amino acid residues was structurally conserved. Epiheterodendrin stimulated appressoria and appressorial hook formation of B. graminis in vitro, suggesting that loss of cyanogenesis in barley leaves has enabled the fungus to utilize the presence of epiheterodendrin to facilitate host recognition and to establish infection.

  15. 芍药白粉病的空间分布型及抽样技术∗%Spatial Distribution Pattern and Sampling Method of Peony Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    何玉会; 马海霞; 瞿小杰; 李茜; 杨信东

    2014-01-01

    对芍药白粉病的空间分布型进行研究,结果表明:芍药白粉病的空间分布型为聚集分布。芍药白粉病的理论抽样数研究结果表明:若想获得精确的调查结果,在常见的发病条件下(每个植株的病级数为1~5),大约需要调查200~700个植株。如果想获得较为精确的调查结果,在常见的发病条件下(每个植株的病级数为1~5),大约需要调查50~170个植株。另外还制定了指导防治工作的序贯抽样检索表。%Peony samples with powdery mildew were collected in Changchun, Jilin province in this study. The spatial distribution of the peony powdery mildew was found to be in a pattern of aggrega⁃ted distribution. In addition, optimum sample number for analyzing peony powdery mildew was de⁃termined. The field survey results showed that, under normal disease condition, 200—700 plant samples ( 1—5 disease grade of peony powdery mildew per plant) were required to analyze data with high precision; while 50—170 plant samples ( 1—5 disease grade of peony powdery mildew per plant) were required to analyze data with moderate precision. A sequential sampling search table was established, which can be used for directing peony powdery mildew disease control.

  16. Prediction Model for Predicting Powdery Mildew using ANN for Medicinal Plant—Picrorhiza kurrooa

    Science.gov (United States)

    Shivling, V. D.; Ghanshyam, C.; Kumar, Rakesh; Kumar, Sanjay; Sharma, Radhika; Kumar, Dinesh; Sharma, Atul; Sharma, Sudhir Kumar

    2016-06-01

    Plant disease fore casting system is an important system as it can be used for prediction of disease, further it can be used as an alert system to warn the farmers in advance so as to protect their crop from being getting infected. Fore casting system will predict the risk of infection for crop by using the environmental factors that favor in germination of disease. In this study an artificial neural network based system for predicting the risk of powdery mildew in Picrorhiza kurrooa was developed. For development, Levenberg-Marquardt backpropagation algorithm was used having a single hidden layer of ten nodes. Temperature and duration of wetness are the major environmental factors that favor infection. Experimental data was used as a training set and some percentage of data was used for testing and validation. The performance of the system was measured in the form of the coefficient of correlation (R), coefficient of determination (R2), mean square error and root mean square error. For simulating the network an inter face was developed. Using this interface the network was simulated by putting temperature and wetness duration so as to predict the level of risk at that particular value of the input data.

  17. Inheritance of Resistance to Powdery Mildew Race 1W in Watermelon.

    Science.gov (United States)

    Ben-Naim, Yariv; Cohen, Yigal

    2015-11-01

    Powdery mildew caused by Podosphaera xanthii is a major disease of watermelon in Israel. In this study, 291 accessions of Citrullus spp. were evaluated for resistance against P. xanthii race 1W. Only eight accessions exhibited high level of resistance. Inheritance of resistance against P. xanthii race 1W was studied by crossing three resistant accession of Citrullus lanatus var. citroides BIU 119, PI 189225, or PI 482312 with the susceptible cultivar 'Malali' or 'Sugar Baby'. Parents, F1, F2, and back cross progenies were evaluated for resistance in growth chambers at the cotyledon stage and the 4-leaf stage and in the field, at the 15-leaf stage. Resistance at the cotyledon stage was controlled by a single, partially dominant gene, whereas at the 4-leaf stage or the 15-leaf stage resistance was controlled by three complimentary, partially dominant genes. Crosses made among these resistant accessions revealed that BIU 119 and PI 189225 carry the same genes for resistance, whereas PI 482312 shares two out of three genes with both BIU 119 and PI 189225. A breeding line with high resistance level and good fruit qualities was developed from BIU 119 × HA5500.

  18. Heterogeneity of Powdery Mildew Resistance Revealed in Accessions of the ICARDA Wild Barley Collection

    Science.gov (United States)

    Dreiseitl, Antonin

    2017-01-01

    The primary genepool of barley comprises two subspecies – wild barley (Hordeum vulgare subsp. spontaneum) and cultivated barley H. vulgare. subsp. vulgare. The former originated 5.5 million years ago in southwest Asia and is the immediate ancestor of cultivated barley, which arose around 10,000 years ago. In this study, the specific resistance of a set of 146 wild barley accessions, maintained by the International Center for Agriculture Research in the Dry Areas (ICARDA), to 32 isolates of barley powdery mildew caused by Blumeria graminis f. sp. hordei was evaluated. The set comprised 146 heterogeneous accessions of a previously tested collection. Seed was obtained by single seed descent and each accession was usually represented by five single plant progenies. In total, 687 plant progenies were tested. There were 211 phenotypes of resistance among the accessions, 87 of which were found in single plants, while 202 plants contained the eight most common phenotypes. The most frequent phenotype was found in 56 plants that were susceptible to all pathogen isolates, whereas the second most frequent phenotype, which occurred in 46 plants, was resistant to all isolates. The broad resistance diversity that was revealed is of practical importance and is an aid to determining the extent and role of resistance in natural ecosystems.

  19. A new putative alphapartitivirus recovered from the powdery mildew fungus Erysiphe palczewskii.

    Science.gov (United States)

    Xiong, Guihong; Qiu, Ping; Li, Cong; Chen, Zhuo; Islam, Saif Ul; Fang, Shouguo; Wu, Zujian; Zhang, Songbai; Du, Zhenguo

    2017-02-27

    Two double-stranded RNAs (dsRNA) likely representing the genome of a novel alphapartitivirus which we provisionally named Erysiphe palczewskii alphapartitivirus 1 (EpV1) were recovered from the powdery mildew fungus E. palczewskii infecting Sophora japonica in Jingzhou, Hubei province of China. The two dsRNAs, 1955 (dsRNA1) and 1917 (dsRNA2) bp in size, respectively, each contains a single open reading frame (ORF) encoding a 585- and 528-aa protein, respectively. The 585-aa protein contains a conserved RNA-dependent RNA polymerase (RdRp) domain and shows significant homology to RdRps of approved or putative partitiviruses, particularly those belonging to the genus Alphapartitivirus. However, it shares an aa sequence identity lower than 80% with its closest relative, the RdRp of the putative alphapartitivirus Grapevine partitivirus, and lower than 60% with the RdRps of other partitiviruses. In a phylogenetic tree constructed with RdRp aa sequences of selected partitiviruses, the putative virus EpV1 clustered with Grapevine partitivirus and formed a well-supported monophyletic clade with known or putative alphapartitiviruses.

  20. Genetic control of common bean (Phaseolus vulgaris resistance to powdery mildew (Erysiphe polygoni

    Directory of Open Access Journals (Sweden)

    Rezende Viviane Ferreira

    1999-01-01

    Full Text Available Genetic control of common bean (Phaseolus vulgaris resistance to powdery mildew (Erysiphe polygoni was studied using segregating populations from the bean variety crosses Jalo x ESAL 686 and ESAL 550 x ESAL 686. F2 plants, together with the parents, were inoculated and evaluated using a scale of values from one (plant without symptoms to nine (completely infected plant. F2 plants were harvested individually, and F2:3 families were obtained. These families were evaluated in an 11 x 11 and 12 x 12 simple lattice statistical design for the Jalo x ESAL 686 and ESAL 550 x ESAL 686 crosses, respectively, using the same value scale as the F2 generation. The segregation observed in F2 plants and F2:3 families indicated that two genes are involved in genetic control, due to a double recessive epistasis. The high linear regression coefficient (b between F2 plants and their F2:3 family, 0.66 for ESAL 550 x ESAL 686 cross, and 0.71 for Jalo x ESAL 686 cross, showed that the trait is highly heritable.

  1. Allele mining in barley genetic resources reveals genes of race-nonspecific powdery mildew resistance

    Directory of Open Access Journals (Sweden)

    Annika eSpies

    2012-01-01

    Full Text Available Race-nonspecific, or quantitative, pathogen resistance is of high importance to plant breeders due to its expected durability. However, it is usually controlled by multiple quantitative trait loci (QTL and therefore difficult to handle in practice. Knowing the genes that underlie race-nonspecific resistance would allow its exploitation in a more targeted manner. Here, we performed an association-genetic study in a customized worlwide collection of spring barley accessions for candidate genes of race-nonspecific resistance to the powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh and combined data with results from QTL-mapping- as well as functional-genomics approaches. This led to the idenfication of 11 associated genes with converging evidence for an important role in race-nonspecific resistance in the presence of the Mlo-gene for basal susceptibility. Outstanding in this respect was the gene encoding the transcription factor WRKY2. The results suggest that unlocking plant genetic resources and integrating functional-genomic with genetic approaches accelerates the discovery of genes underlying race-nonspecific resistance in barley and other crop plants.

  2. Tempered mlo broad-spectrum resistance to barley powdery mildew in an Ethiopian landrace.

    Science.gov (United States)

    Ge, Xintian; Deng, Weiwei; Lee, Zheng Zhou; Lopez-Ruiz, Francisco J; Schweizer, Patrick; Ellwood, Simon R

    2016-07-12

    Recessive mutations in the Mlo gene confer broad spectrum resistance in barley (Hordeum vulgare) to powdery mildew (Blumeria graminis f. sp. hordei), a widespread and damaging disease. However, all alleles discovered to date also display deleterious pleiotropic effects, including the naturally occurring mlo-11 mutant which is widely deployed in Europe. Recessive resistance was discovered in Eth295, an Ethiopian landrace, which was developmentally controlled and quantitative without spontaneous cell wall appositions or extensive necrosis and loss of photosynthetic tissue. This resistance is determined by two copies of the mlo-11 repeat units, that occur upstream to the wild-type Mlo gene, compared to 11-12 in commonly grown cultivars and was designated mlo-11 (cnv2). mlo-11 repeat unit copy number-dependent DNA methylation corresponded with cytological and macroscopic phenotypic differences between copy number variants. Sequence data indicated mlo-11 (cnv2) formed via recombination between progenitor mlo-11 repeat units and the 3' end of an adjacent stowaway MITE containing region. mlo-11 (cnv2) is the only example of a moderated mlo variant discovered to date and may have arisen by natural selection against the deleterious effects of the progenitor mlo-11 repeat unit configuration.

  3. Essential oils: an alternative approach to management of powdery mildew diseases

    Directory of Open Access Journals (Sweden)

    Elena STURCHIO

    2015-01-01

    Full Text Available In recent years there has been growing interest in the application of plant-derived substances in agriculture as alternatives to the use of pesticides, in order to obtain healthy crops and more environmentally sustainable crop production systems. The properties of some essential oils as natural fungicides were evaluated, to promote their use in alternative agriculture. Potentially detrimental effects caused by essential oil residues in soil were also assessed by mutagenicity assays to avoid possible adverse effects related to the use of these materials. Trials in a controlled environment were set up, using ‘Romanesco’ zucchini treated with essential oils, either exclusively or alternated with a synthetic fungicide. The treatments were applied when natural infection by Podosphaera xanthii appeared on test plants, and powdery mildew incidence and severity were assessed after six weeks. Preliminary results indicated that the alternation of natural materials with effective synthetic fungicide maintained effective disease control, and may also assist with management of pesticide resistance in P. xanthii. No relevant mutagenic effects of essential oil residues in soil were revealed, although an appropriate formulation useful under field conditions is required for effective application.

  4. Prediction Model for Predicting Powdery Mildew using ANN for Medicinal Plant— Picrorhiza kurrooa

    Science.gov (United States)

    Shivling, V. D.; Ghanshyam, C.; Kumar, Rakesh; Kumar, Sanjay; Sharma, Radhika; Kumar, Dinesh; Sharma, Atul; Sharma, Sudhir Kumar

    2017-02-01

    Plant disease fore casting system is an important system as it can be used for prediction of disease, further it can be used as an alert system to warn the farmers in advance so as to protect their crop from being getting infected. Fore casting system will predict the risk of infection for crop by using the environmental factors that favor in germination of disease. In this study an artificial neural network based system for predicting the risk of powdery mildew in Picrorhiza kurrooa was developed. For development, Levenberg-Marquardt backpropagation algorithm was used having a single hidden layer of ten nodes. Temperature and duration of wetness are the major environmental factors that favor infection. Experimental data was used as a training set and some percentage of data was used for testing and validation. The performance of the system was measured in the form of the coefficient of correlation (R), coefficient of determination (R2), mean square error and root mean square error. For simulating the network an inter face was developed. Using this interface the network was simulated by putting temperature and wetness duration so as to predict the level of risk at that particular value of the input data.

  5. Gene Location and Molecular Markers of Powdery Mildew Resistance in Wheat%小麦抗白粉病基因定位与分子标记

    Institute of Scientific and Technical Information of China (English)

    胡英考; 辛志勇

    2000-01-01

    Genetic location and molecular markers of powdery mildew resistance genes in wheat were reviewed. The inheritance of powdery mildew resistance was also introduced. The research perspective was discussed in this paper%对小麦抗白粉病基因的遗传定位与分子标记进行了综述,介绍了小麦抗白粉病的遗传,并对今后的研究方向进行了讨论。

  6. Key Components of Different Plant Defense Pathways Are Dispensable for Powdery Mildew Resistance of the Arabidopsis mlo2 mlo6 mlo12 Triple Mutant

    Directory of Open Access Journals (Sweden)

    Hannah Kuhn

    2017-06-01

    Full Text Available Loss of function mutations of particular plant MILDEW RESISTANCE LOCUS O (MLO genes confer durable and broad-spectrum penetration resistance against powdery mildew fungi. Here, we combined genetic, transcriptomic and metabolomic analyses to explore the defense mechanisms in the fully resistant Arabidopsis thaliana mlo2 mlo6 mlo12 triple mutant. We found that this genotype unexpectedly overcomes the requirement for indolic antimicrobials and defense-related secretion, which are critical for incomplete resistance of mlo2 single mutants. Comparative microarray-based transcriptome analysis of mlo2 mlo6 mlo12 mutants and wild type plants upon Golovinomyces orontii inoculation revealed an increased and accelerated accumulation of many defense-related transcripts. Despite the biotrophic nature of the interaction, this included the non-canonical activation of a jasmonic acid/ethylene-dependent transcriptional program. In contrast to a non-adapted powdery mildew pathogen, the adapted powdery mildew fungus is able to defeat the accumulation of defense-relevant indolic metabolites in a MLO protein-dependent manner. We suggest that a broad and fast activation of immune responses in mlo2 mlo6 mlo12 plants can compensate for the lack of single or few defense pathways. In addition, our results point to a role of Arabidopsis MLO2, MLO6, and MLO12 in enabling defense suppression during invasion by adapted powdery mildew fungi.

  7. A component of the Sec61 ER protein transporting pore is required for plant susceptibility to powdery mildew

    Directory of Open Access Journals (Sweden)

    Wen-Jing eZhang

    2013-05-01

    Full Text Available Biotrophic pathogens, like the powdery mildew fungi, require living plant cells for their growth and reproduction. During infection, a specialized structure called the haustorium is formed by the fungus. The haustorium is surrounded by a plant cell-derived extrahaustorial membrane (EHM. Over the EHM, the fungus obtains nutrients from and secretes effectors into the plant cell. In the plant cell these effectors interfere with cellular processes such as pathogen defense and membrane trafficking. However, the mechanisms behind effector delivery are largely unknown. This paper provides a model for and new insights into a putative transfer mechanism of effectors into the plant cell. We show that silencing of the barley Sec61βa protein results in decreased susceptibility to the powdery mildew fungus. HvSec61βa is a component of both the endoplasmic reticulum (ER translocon and retrotranslocon pores, the latter being part of the ER-associated protein degradation machinery (ERAD. We provide support for a model suggesting that the retrotranslocon function of HvSec61βa is required for successful powdery mildew fungal infection. HvSec61βa-GFP and a luminal ER marker were co-localized to the ER, which was found to be in close proximity to the EHM around the haustorial body, but not the haustorial fingers. This differential EHM proximity suggests that the ER, including HvSec61βa, may be actively recruited by the haustorium, potentially to provide efficient effector transfer to the cytosol. Effector transport across this EHM-ER interface may occur by a vesicle-mediated process, while the Sec61 retrotranslocon pore potentially provides an escape route for these proteins to reach the cytosol.

  8. A component of the Sec61 ER protein transporting pore is required for plant susceptibility to powdery mildew.

    Science.gov (United States)

    Zhang, Wen-Jing; Hanisch, Susanne; Kwaaitaal, Mark; Pedersen, Carsten; Thordal-Christensen, Hans

    2013-01-01

    Biotrophic pathogens, like the powdery mildew fungi, require living plant cells for their growth and reproduction. During infection, a specialized structure called the haustorium is formed by the fungus. The haustorium is surrounded by a plant cell-derived extrahaustorial membrane (EHM). Over the EHM, the fungus obtains nutrients from and secretes effector proteins into the plant cell. In the plant cell these effectors interfere with cellular processes such as pathogen defense and membrane trafficking. However, the mechanisms behind effector delivery are largely unknown. This paper provides a model for and new insights into a putative transfer mechanism of effectors into the plant cell. We show that silencing of the barley Sec61βa transcript results in decreased susceptibility to the powdery mildew fungus. HvSec61βa is a component of both the endoplasmic reticulum (ER) translocon and retrotranslocon pores, the latter being part of the ER-associated protein degradation machinery. We provide support for a model suggesting that the retrotranslocon function of HvSec61βa is required for successful powdery mildew fungal infection. HvSec61βa-GFP and a luminal ER marker were co-localized to the ER, which was found to be in close proximity to the EHM around the haustorial body, but not the haustorial fingers. This differential EHM proximity suggests that the ER, including HvSec61βa, may be actively recruited by the haustorium, potentially to provide efficient effector transfer to the cytosol. Effector transport across this EHM-ER interface may occur by a vesicle-mediated process, while the Sec61 retrotranslocon pore potentially provides an escape route for these proteins to reach the cytosol.

  9. Mapping of Powdery Mildew Resistance Gene pmCH89 in a Putative Wheat-Thinopyrum intermedium Introgression Line

    Directory of Open Access Journals (Sweden)

    Liyuan Hou

    2015-07-01

    Full Text Available Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt, is a globally serious disease adversely affecting wheat production. The Bgt-resistant wheat breeding line CH09W89 was derived after backcrossing a Bgt resistant wheat-Thinopyrum intermedium partial amphiploid TAI7045 with susceptible wheat cultivars. At the seedling stage, CH09W89 exhibited immunity or high resistance to Bgt pathotypes E09, E20, E21, E23, E26, Bg1, and Bg2, similar to its donor line TAI7045 and Th. intermedium. No Th. intermedium chromatin was detected based on genomic in situ hybridization of mitotic chromosomes. To determine the mode of inheritance of the Bgt resistance and the chromosomal location of the resistance gene, CH09W89 was crossed with two susceptible wheat cultivars. The results of the genetic analysis showed that the adult resistance to Bgt E09 in CH09W89 was controlled by a single recessive gene, which was tentatively designated as pmCH89. Two polymorphic SSR markers, Xwmc310 and Xwmc125, were linked to the resistance gene with genetic distances 3.1 and 2.7 cM, respectively. Using the Chinese Spring aneuploid and deletion lines, the resistance gene and its linked markers were assigned to chromosome arm 4BL in the bin 0.68–0.78. Due to its unique position on chromosome 4BL, pmCH89 appears to be a new locus for resistance to powdery mildew. These results will be of benefit for improving powdery mildew resistance in wheat breeding programs.

  10. Molecular Cytogenetic Identification of a New Wheat-Rye 6R Chromosome Disomic Addition Line with Powdery Mildew Resistance.

    Directory of Open Access Journals (Sweden)

    Diaoguo An

    Full Text Available Rye (Secale cereale L. possesses many valuable genes that can be used for improving disease resistance, yield and environment adaptation of wheat (Triticum aestivum L.. However, the documented resistance stocks derived from rye is faced severe challenge due to the variation of virulent isolates in the pathogen populations. Therefore, it is necessary to develop desirable germplasm and search for novel resistance gene sources against constantly accumulated variation of the virulent isolates. In the present study, a new wheat-rye line designated as WR49-1 was produced through distant hybridization and chromosome engineering protocols between common wheat cultivar Xiaoyan 6 and rye cultivar German White. Using sequential GISH (genomic in situ hybridization, mc-FISH (multicolor fluorescence in situ hybridization, mc-GISH (multicolor GISH and EST (expressed sequence tag-based marker analysis, WR49-1 was proved to be a new wheat-rye 6R disomic addition line. As expected, WR49-1 showed high levels of resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici, Bgt pathogens prevalent in China at the adult growth stage and 19 of 23 Bgt isolates tested at the seedling stage. According to its reaction pattern to different Bgt isolates, WR49-1 may possess new resistance gene(s for powdery mildew, which differed from the documented powdery mildew gene, including Pm20 on chromosome arm 6RL of rye. Additionally, WR49-1 was cytologically stable, had improved agronomic characteristics and therefore could serve as an important bridge for wheat breeding and chromosome engineering.

  11. Nuclear Function of Subclass I Actin-Depolymerizing Factor Contributes to Susceptibility in Arabidopsis to an Adapted Powdery Mildew Fungus.

    Science.gov (United States)

    Inada, Noriko; Higaki, Takumi; Hasezawa, Seiichiro

    2016-03-01

    Actin-depolymerizing factors (ADFs) are conserved proteins that function in regulating the structure and dynamics of actin microfilaments in eukaryotes. In this study, we present evidence that Arabidopsis (Arabidopsis thaliana) subclass I ADFs, particularly ADF4, functions as a susceptibility factor for an adapted powdery mildew fungus. The null mutant of ADF4 significantly increased resistance against the adapted powdery mildew fungus Golovinomyces orontii. The degree of resistance was further enhanced in transgenic plants in which the expression of all subclass I ADFs (i.e. ADF1-ADF4) was suppressed. Microscopic observations revealed that the enhanced resistance of adf4 and ADF1-4 knockdown plants (ADF1-4Ri) was associated with the accumulation of hydrogen peroxide and cell death specific to G. orontii-infected cells. The increased resistance and accumulation of hydrogen peroxide in ADF1-4Ri were suppressed by the introduction of mutations in the salicylic acid- and jasmonic acid-signaling pathways but not by a mutation in the ethylene-signaling pathway. Quantification by microscopic images detected an increase in the level of actin microfilament bundling in ADF1-4Ri but not in adf4 at early G. orontii infection time points. Interestingly, complementation analysis revealed that nuclear localization of ADF4 was crucial for susceptibility to G. orontii. Based on its G. orontii-infected-cell-specific phenotype, we suggest that subclass I ADFs are susceptibility factors that function in a direct interaction between the host plant and the powdery mildew fungus.

  12. The powdery mildew resistance gene Pm8 derived from rye is suppressed by its wheat ortholog Pm3.

    Science.gov (United States)

    Hurni, Severine; Brunner, Susanne; Stirnweis, Daniel; Herren, Gerhard; Peditto, David; McIntosh, Robert A; Keller, Beat

    2014-09-01

    The powdery mildew resistance gene Pm8 derived from rye is located on a 1BL.1RS chromosome translocation in wheat. However, some wheat lines with this translocation do not show resistance to isolates of the wheat powdery mildew pathogen avirulent to Pm8 due to an unknown genetically dominant suppression mechanism. Here we show that lines with suppressed Pm8 activity contain an intact and expressed Pm8 gene. Therefore, the absence of Pm8 function in certain 1BL.1RS-containing wheat lines is not the result of gene loss or mutation but is based on suppression. The wheat gene Pm3, an ortholog of rye Pm8, suppressed Pm8-mediated powdery mildew resistance in lines containing Pm8 in a transient single-cell expression assay. This result was further confirmed in transgenic lines with combined Pm8 and Pm3 transgenes. Expression analysis revealed that suppression is not the result of gene silencing, either in wheat 1BL.1RS translocation lines carrying Pm8 or in transgenic genotypes with both Pm8 and Pm3 alleles. In addition, a similar abundance of the PM8 and PM3 proteins in single or double homozygous transgenic lines suggested that a post-translational mechanism is involved in suppression of Pm8. Co-expression of Pm8 and Pm3 genes in Nicotiana benthamiana leaves followed by co-immunoprecipitation analysis showed that the two proteins interact. Therefore, the formation of a heteromeric protein complex might result in inefficient or absent signal transmission for the defense reaction. These data provide a molecular explanation for the suppression of resistance genes in certain genetic backgrounds and suggest ways to circumvent it in future plant breeding.

  13. Collinearity Analysis and High-Density Genetic Mapping of the Wheat Powdery Mildew Resistance Gene Pm40 in PI 672538.

    Science.gov (United States)

    Zhong, Shengfu; Ma, Lixia; Fatima, Syeda Akash; Yang, Jiezhi; Chen, Wanquan; Liu, Taiguo; Hu, Yuting; Li, Qing; Guo, Jingwei; Zhang, Min; Lei, Li; Li, Xin; Tang, Shengwen; Luo, Peigao

    2016-01-01

    The wheat powdery mildew resistance gene Pm40, which is located on chromosomal arm 7BS, is effective against nearly all prevalent races of Blumeria graminis f. sp tritici (Bgt) in China and is carried by the common wheat germplasm PI 672538. A set of the F1, F2 and F2:3 populations from the cross of the resistant PI 672538 with the susceptible line L1034 were used to conduct genetic analysis of powdery mildew resistance and construct a high-density linkage map of the Pm40 gene. We constructed a high-density linkage genetic map with a total length of 6.18 cM and average spacing between markers of 0.48 cM.Pm40 is flanked by Xwmc335 and BF291338 at genetic distances of 0.58 cM and 0.26 cM, respectively, in deletion bin C-7BS-1-0.27. Comparative genomic analysis based on EST-STS markers established a high level of collinearity of the Pm40 genomic region with a 1.09-Mbp genomic region on Brachypodium chromosome 3, a 1.16-Mbp genomic region on rice chromosome 8, and a 1.62-Mbp genomic region on sorghum chromosome 7. We further anchored the Pm40 target intervals to the wheat genome sequence. A putative linear index of 85 wheat contigs containing 97 genes on 7BS was constructed. In total, 9 genes could be considered as candidates for the resistances to powdery mildew in the target genomic regions, which encoded proteins that were involved in the plant defense and response to pathogen attack. These results will facilitate the development of new markers for map-based cloning and marker-assisted selection of Pm40 in wheat breeding programs.

  14. Characterization of a New Pm2 Allele Conferring Powdery Mildew Resistance in the Wheat Germplasm Line FG-1.

    Science.gov (United States)

    Ma, Pengtao; Xu, Hongxng; Li, Lihui; Zhang, Hongxia; Han, Guohao; Xu, Yunfeng; Fu, Xiaoyi; Zhang, Xiaotian; An, Diaoguo

    2016-01-01

    Powdery mildew has a negative impact on wheat production. Novel host resistance increases the diversity of resistance genes and helps to control the disease. In this study, wheat line FG-1 imported from France showed a high level of powdery mildew resistance at both the seedling and adult stages. An F2 population and F2:3 families from the cross FG-1 × Mingxian 169 both fit Mendelian ratios for a single dominant resistance gene when tested against multiple avirulent Blumeria tritici f. sp. tritici (Bgt) races. This gene was temporarily designated PmFG. PmFG was mapped on the multi-allelic Pm2 locus of chromosome 5DS using seven SSR, 10 single nucleotide polymorphism (SNP)-derived and two SCAR markers with the flanking markers Xbwm21/Xcfd81/Xscar112 (distal) and Xbwm25 (proximal) at 0.3 and 0.5 cM being the closest. Marker SCAR203 co-segregated with PmFG. Allelism tests between PmFG and documented Pm2 alleles confirmed that PmFG was allelic with Pm2. Line FG-1 produced a significantly different reaction pattern compared to other lines with genes at or near Pm2 when tested against 49 Bgt isolates. The PmFG-linked marker alleles detected by the SNP-derived markers revealed significant variation between FG-1 and other lines with genes at or near Pm2. It was concluded that PmFG is a new allele at the Pm2 locus. Data from seven closely linked markers tested on 31 wheat cultivars indicated opportunities for marker-assisted pyramiding of this gene with other genes for powdery mildew resistance and additional traits.

  15. Mapping of Powdery Mildew Resistance Gene pmCH89 in a Putative Wheat-Thinopyrum intermedium Introgression Line.

    Science.gov (United States)

    Hou, Liyuan; Zhang, Xiaojun; Li, Xin; Jia, Juqing; Yang, Huizhen; Zhan, Haixian; Qiao, Linyi; Guo, Huijuan; Chang, Zhijian

    2015-07-28

    Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a globally serious disease adversely affecting wheat production. The Bgt-resistant wheat breeding line CH09W89 was derived after backcrossing a Bgt resistant wheat-Thinopyrum intermedium partial amphiploid TAI7045 with susceptible wheat cultivars. At the seedling stage, CH09W89 exhibited immunity or high resistance to Bgt pathotypes E09, E20, E21, E23, E26, Bg1, and Bg2, similar to its donor line TAI7045 and Th. intermedium. No Th. intermedium chromatin was detected based on genomic in situ hybridization of mitotic chromosomes. To determine the mode of inheritance of the Bgt resistance and the chromosomal location of the resistance gene, CH09W89 was crossed with two susceptible wheat cultivars. The results of the genetic analysis showed that the adult resistance to Bgt E09 in CH09W89 was controlled by a single recessive gene, which was tentatively designated as pmCH89. Two polymorphic SSR markers, Xwmc310 and Xwmc125, were linked to the resistance gene with genetic distances 3.1 and 2.7 cM, respectively. Using the Chinese Spring aneuploid and deletion lines, the resistance gene and its linked markers were assigned to chromosome arm 4BL in the bin 0.68-0.78. Due to its unique position on chromosome 4BL, pmCH89 appears to be a new locus for resistance to powdery mildew. These results will be of benefit for improving powdery mildew resistance in wheat breeding programs.

  16. Cultivar-Based Introgression Mapping Reveals Wild Species-Derived Pm-0, the Major Powdery Mildew Resistance Locus in Squash.

    Science.gov (United States)

    Holdsworth, William L; LaPlant, Kyle E; Bell, Duane C; Jahn, Molly M; Mazourek, Michael

    2016-01-01

    Powdery mildew is a major fungal disease on squash and pumpkin (Cucurbita spp.) in the US and throughout the world. Genetic resistance to the disease is not known to occur naturally within Cucurbita pepo and only infrequently in Cucurbita moschata, but has been achieved in both species through the introgression of a major resistance gene from the wild species Cucurbita okeechobeensis subsp. martinezii. At present, this gene, Pm-0, is used extensively in breeding, and is found in nearly all powdery mildew-resistant C. pepo and C. moschata commercial cultivars. In this study, we mapped C. okeechobeensis subsp. martinezii-derived single nucleotide polymorphism (SNP) alleles in a set of taxonomically and morphologically diverse and resistant C. pepo and C. moschata cultivars bred at Cornell University that, by common possession of Pm-0, form a shared-trait introgression panel. High marker density was achieved using genotyping-by-sequencing, which yielded over 50,000 de novo SNP markers in each of the three Cucurbita species genotyped. A single 516.4 kb wild-derived introgression was present in all of the resistant cultivars and absent in a diverse set of heirlooms that predated the Pm-0 introgression. The contribution of this interval to powdery mildew resistance was confirmed by association mapping in a C. pepo cultivar panel that included the Cornell lines, heirlooms, and 68 additional C. pepo cultivars and with an independent F2 population derived from C. okeechobeensis subsp. martinezii x C. moschata. The interval was refined to a final candidate interval of 76.4 kb and CAPS markers were developed inside this interval to facilitate marker-assisted selection.

  17. Collinearity Analysis and High-Density Genetic Mapping of the Wheat Powdery Mildew Resistance Gene Pm40 in PI 672538

    Science.gov (United States)

    Fatima, Syeda Akash; Yang, Jiezhi; Chen, Wanquan; Liu, Taiguo; Hu, Yuting; Li, Qing; Guo, Jingwei; Zhang, Min; Lei, Li; Li, Xin; Tang, Shengwen; Luo, Peigao

    2016-01-01

    The wheat powdery mildew resistance gene Pm40, which is located on chromosomal arm 7BS, is effective against nearly all prevalent races of Blumeria graminis f. sp tritici (Bgt) in China and is carried by the common wheat germplasm PI 672538. A set of the F1, F2 and F2:3 populations from the cross of the resistant PI 672538 with the susceptible line L1034 were used to conduct genetic analysis of powdery mildew resistance and construct a high-density linkage map of the Pm40 gene. We constructed a high-density linkage genetic map with a total length of 6.18 cM and average spacing between markers of 0.48 cM.Pm40 is flanked by Xwmc335 and BF291338 at genetic distances of 0.58 cM and 0.26 cM, respectively, in deletion bin C-7BS-1-0.27. Comparative genomic analysis based on EST-STS markers established a high level of collinearity of the Pm40 genomic region with a 1.09-Mbp genomic region on Brachypodium chromosome 3, a 1.16-Mbp genomic region on rice chromosome 8, and a 1.62-Mbp genomic region on sorghum chromosome 7. We further anchored the Pm40 target intervals to the wheat genome sequence. A putative linear index of 85 wheat contigs containing 97 genes on 7BS was constructed. In total, 9 genes could be considered as candidates for the resistances to powdery mildew in the target genomic regions, which encoded proteins that were involved in the plant defense and response to pathogen attack. These results will facilitate the development of new markers for map-based cloning and marker-assisted selection of Pm40 in wheat breeding programs. PMID:27755575

  18. Localization of the Laevigatum powdery mildew resistance gene to barley chromosome 2 by the use of RFLP markers

    DEFF Research Database (Denmark)

    Giese, H.; Holm-Jensen, A.G.; Jensen, H.P.;

    1993-01-01

    The powdery mildew disease resistance gene Ml(La) was found to belong to a locus on barely chromosome 2. We suggest that this locus be designated MlLa. Linkage analysis was carried out on 72 chromosome-doubled, spring-type progeny lines from a cross between the winter var 'Vogelsanger Gold' and t......' and the spring var 'Alf'. A map of chromosome 2 spanning 119 cM and flanked by two peroxidase gene loci was constructed. In addition to the Laevigatum resistance locus the map includes nine RFLP markers, the two peroxidase gene loci and the six-row locus in barley....

  19. Systemic Resistance to Powdery Mildew in Brassica napus (AACC) and Raphanus alboglabra (RRCC) by Trichoderma harzianum TH12.

    Science.gov (United States)

    Alkooranee, Jawadayn Talib; Yin, Yongtai; Aledan, Tamarah Raad; Jiang, Yingfen; Lu, Guangyuan; Wu, Jiangsheng; Li, Maoteng

    2015-01-01

    Trichoderma harzianum TH12 is a microbial pesticide for certain rapeseed diseases. The mechanism of systemic resistance induced by TH12 or its cell-free culture filtrate (CF) in Brassica napus (AACC) and Raphanus alboglabra (RRCC) to powdery mildew disease caused by ascomycete Erysiphe cruciferarum was investigated. In this study, we conducted the first large-scale global study on the cellular and molecular aspects of B. napus and R. alboglabra infected with E. cruciferarum. The histological study showed the resistance of R. alboglabra to powdery mildew disease. The growth of fungal colonies was not observed on R. alboglabra leaves at 1, 2, 4, 6, 8, and 10 days post-inoculation (dpi), whereas this was clearly observed on B. napus leaves after 6 dpi. In addition, the gene expression of six plant defense-related genes, namely, PR-1, PR-2 (a marker for SA signaling), PR-3, PDF 1.2 (a marker for JA/ET signaling), CHI620, and CHI570, for both genotypes were analyzed in the leaves of B. napus and R. alboglabra after treatment with TH12 or CF and compared with the non-treated ones. The qRT-PCR results showed that the PR-1 and PR-2 expression levels increased in E. cruciferarum-infected leaves, but decreased in the TH12-treated leaves compared with leaves treated with CF. The expression levels of PR-3 and PDF1.2 decreased in plants infected by E. cruciferarum. However, expression levels increased when the leaves were treated with TH12. For the first time, we disclosed the nature of gene expression in B. napus and R. alboglabra to explore the resistance pathways in the leaves of both genotypes infected and non-infected by powdery mildew and inoculated or non-inoculated with elicitor factors. Results suggested that R. alboglabra exhibited resistance to powdery mildew disease, and the application of T. harzianum and its CF are a useful tool to facilitate new protection methods for resist or susceptible plants.

  20. Identification and structure of the mating-type locus and development of PCR-based markers for mating type in powdery mildew fungi.

    Science.gov (United States)

    Brewer, Marin Talbot; Cadle-Davidson, Lance; Cortesi, Paolo; Spanu, Pietro D; Milgroom, Michael G

    2011-07-01

    In ascomycetes, mating compatibility is regulated by the mating-type locus, MAT1. The objectives of this study were to identify and sequence genes at the MAT1 locus in the grape powdery mildew fungus, Erysiphe necator, to develop a PCR-based marker for determining mating type in E. necator, and to develop degenerate primers for amplification by PCR of conserved regions of mating-type idiomorphs in other powdery mildew fungi. We identified MAT1-2-1 of the MAT1-2 idiomorph in E. necator based on the homologous sequence in the genome of Blumeria graminis f. sp. hordei and we found MAT1-1-1 and MAT1-1-3 of the MAT1-1 idiomorph from transcriptome sequences of E. necator. We developed and applied a reliable PCR-based multiplex marker to confirm that genotype correlated with mating phenotype, which was determined by pairing with mating-type tester isolates. Additionally, we used the marker to genotype populations of E. necator from different Vitis spp. from throughout the USA. We found both mating types were present in all populations and mating-type ratios did not deviate from 1:1. The mating-type genes in E. necator are similar to those of other Leotiomycetes; however, the structure of the MAT1 locus in E. necator, like the MAT1-2 idiomorph of B. graminis, is markedly different from other ascomycetes in that it is greatly expanded and may contain a large amount of repetitive DNA. As a result, we were unable to amplify and sequence either idiomorph in its entirety. We designed degenerate primers that amplify conserved regions of MAT1-1 and MAT1-2 in E. necator, Podosphaera xanthii, Microsphaera syringae, and B. graminis, representing the major clades of the Erysiphales. These degenerate primers or sequences obtained in this study from these species can be used to identify and sequence MAT1 genes or design mating-type markers in other powdery mildew fungi as well.

  1. BACILLUS SUBTILIS FOR THE CONTROL OF POWDERY MILDEW ON CUCUMBER AND ZUCCHINI SQUASH

    Directory of Open Access Journals (Sweden)

    BETTIOL WAGNER

    1997-01-01

    Full Text Available Application of concentrated metabolites of Bacillus subtilis - CMBS - (5,000 µg/mL one and 24 h before or after inoculation of Sphaerotheca fuliginea (3 x 104 conidia/mL reduced the number of lesions on cucumber leaves by 90-99%. The average number of lesions on control plants was 16.7 per leaf. A wettable powder product formulated with cells (10% and metabolites (10% of B. subtilis (WPBS, and CMBS sprayed on cucumber plants (1,000 µg/mL and 10,000 µg/mL twice a week totally controlled powdery mildew. In the control treatment, 18 days after the first spray, the percent leaf surface covered by lesions was 99.0 and 46.7%, on the cotyledonary and expanded leaves, respectively. In the control treatment, 30 days after the first spray, the percent leaf surface with lesions was 26.1%, while leaves sprayed with CMBS presented no lesions. The fresh weight per plant was 4.3 g in the control treatment; 12.2 g, and 10.2 g for plants sprayed with CMBS at the concentration of 1,000 and 10,000 µg/mL, respectively; and 9.7 g and 10.1 g for plants sprayed with WPBS 1,000 and 10,000 µg/mL, respectively. For zucchini squash, CMBS (5,000 µg/mL sprayed every 2, 4, and 6 days showed reductions in lesioned leaf surface of 100.0, 98.3, and 94.7%, respectively.

  2. Further isolation of AFLP and LMS markers for the mapping of the Ol-2 locus related to powdery mildew (Oidium neolycopersici) resistance in tomato (Solanum lycopersicum L.)

    NARCIS (Netherlands)

    Ricciardi, L.; Lotti, C.; Pavan, S.N.C.; Bai, Y.; Lindhout, P.; Giovanni, de C.

    2007-01-01

    Tomato powdery mildew (Oidium neolycopersici) is a new plant disease that in recent years has frequently occurred in open field and protected environments to cause serious damage to tomato crops. Currently, the development of resistant cultivars appear to be the best eco-compatible solution to contr

  3. The wheat homolog of putative nucleotide-binding site-leucine-rich repeat resistance gene TaRGA contributes to resistance against powdery mildew.

    Science.gov (United States)

    Wang, Defu; Wang, Xiaobing; Mei, Yu; Dong, Hansong

    2016-03-01

    Powdery mildew, one of the most destructive wheat diseases worldwide, is caused by Blumeria graminis f. sp. tritici (Bgt), a fungal species with a consistently high mutation rate that makes individual resistance (R) genes ineffective. Therefore, effective resistance-related gene cloning is vital for breeding and studying the resistance mechanisms of the disease. In this study, a putative nucleotide-binding site-leucine-rich repeat (NBS-LRR) R gene (TaRGA) was cloned using a homology-based cloning strategy and analyzed for its effect on powdery mildew disease and wheat defense responses. Real-time reverse transcription-PCR (RT-PCR) analyses revealed that a Bgt isolate 15 and salicylic acid stimulation significantly induced TaRGA in the resistant variety. Furthermore, the silencing of TaRGA in powdery mildew-resistant plants increased susceptibility to Bgt15 and prompted conidia propagation at the infection site. However, the expression of TaRGA in leaf segments after single-cell transient expression assay highly increased the defense responses to Bgt15 by enhancing callose deposition and phenolic autofluorogen accumulation at the pathogen invading sites. Meanwhile, the expression of pathogenesis-related genes decreased in the TaRGA-silenced plants and increased in the TaRGA-transient-overexpressing leaf segments. These results implied that the TaRGA gene positively regulates the defense response to powdery mildew disease in wheat.

  4. The Lr46 gene conditions partial adult-plant resistance to yellow rust, stem rust, and powdery mildew in Thatcher wheat

    Science.gov (United States)

    Disease resistance is a critical goal for many wheat improvement programs. Wheat cultivars are often attacked by multiple diseases, including the rusts and powdery mildew. F6 recombinant inbred lines (RILs) derived from the cross of Thatcher*3/CI13227 that had been previously characterized as having...

  5. Effects of Powdery Mildew on 1 000-Kernel Weight, Crude Protein Content and Yield of Winter Wheat in Three Consecutive Growing Seasons

    Institute of Scientific and Technical Information of China (English)

    CAO Xue-ren; YAO Dong-ming; DUAN Xia-yu; LIU Wei; FAN Jie-ru; DING Ke-jian; ZHOU Yi-lin

    2014-01-01

    In order to clarify the impact posed by wheat powdery mildew (Blumeria graminis f. sp. tritici) on the yield and yield components in different epidemic seasons, ifeld trials were conducted in three growing seasons, 2009-2010, 2010-2011 and 2011-2012, in Langfang City, Hebei Province, China. The relationships between 1 000-kernel weight, crude protein content of grain and yield and disease index (DI), as well as area under disease progress curve (AUDPC) were studied. The models of the percentage of loss of 1 000-kernel weight, crude protein content and yield were constructed using DI at critical point (CP) of growth stages (GS) and AUDPC in the three growing seasons, respectively. The CPs for estimating 1 000-kernel weight, crude protein content of grain and yield of wheat caused by powdery mildew were GS 11.1, GS 10.5.3 and GS 10.5.3, respectively. Models based on DI at CP to estimate the percentage of loss of 1 000-kernel weight, crude protein content of grain and yield were better than models based on AUDPC. And models of the percentage of loss of 1 000-kernel weight, crude protein content and yield for 2011-2012 season were signiifcant different from these for 2009-2010 and 2010-2011 seasons. These results indicated that besides powdery mildew, weather conditions also had inlfuence on 1 000-kernel weight, crude protein content of grain and yield loss of wheat when powdery mildew occurred.

  6. Selection of New Wheat Germplam with Resistance to Powdery Mildew from Haynalddia villosa%簇毛麦抗白粉病新种质的选育

    Institute of Scientific and Technical Information of China (English)

    刘润堂

    2011-01-01

    Wheat powdery mildew is one of wheat main diseases. We used Haynaldia villosa as antigens, gene resistance to powdery mildew from Haynaldia villosa was introduced to wheat through crossing radiation and young embryo culture. By disease resistant identification, systematic selection and cell analysis, we have selected high yield varieties and new germplasm with good agronomic characters and resistance to powdery mildew. By DNA analysis, gene resistant to powdery mildew from Haynaldia villosa has been joined to wheat varieties.%小麦白粉病是小麦的主要病害之一.以簇毛麦为抗源,采用杂交与辐射、组织培养相结合的方法,将簇毛麦的抗白粉病基因导入小麦.经抗病鉴定、系统选育和细胞学分析,选育出农艺性状较好、抗白粉病的小麦新种质.经DNA分析,证明簇毛麦抗白粉病基因(或染色体片断)已被导入小麦品种.

  7. Use of potassium bicarbonate (Armicarb) on the control of powdery mildew (Sphaerotheca mors-uvae) of gooseberry (Ribes uva-crispa)

    NARCIS (Netherlands)

    Wenneker, M.; Kanne, H.J.

    2011-01-01

    Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots, stems and fruits of gooseberry (Ribes uva-crispa). Environmental friendly and biological control measures are being sought throughout the world. Especially in organic gooseberry growing effective control measures are needed, beca

  8. Oidium neolycopersici: Intra-specific variability inferred from AFLP analysis and relationship with closely related powdery mildew fungi infecting various plant species

    NARCIS (Netherlands)

    Jankovics, T.; Bai, Y.; Kovacs, G.M.; Bardin, M.; Nicot, P.C.; Toyoda, H.; Matsuda, Y.; Niks, R.E.; Kiss, L.

    2008-01-01

    Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length

  9. Dominant negative RPW8.2 fusion proteins reveal the importance of haustorium-oriented protein trafficking for resistance against powdery mildew in Arabidopsis.

    Science.gov (United States)

    Zhang, Qiong; Berkey, Robert; Pan, Zhiyong; Wang, Wenming; Zhang, Yi; Ma, Xianfeng; King, Harlan; Xiao, Shunyuan

    2015-01-01

    Powdery mildew fungi form feeding structures called haustoria inside epidermal cells of host plants to extract photosynthates for their epiphytic growth and reproduction. The haustorium is encased by an interfacial membrane termed the extrahaustorial membrane (EHM). The atypical resistance protein RPW8.2 from Arabidopsis is specifically targeted to the EHM where RPW8.2 activates haustorium-targeted (thus broad-spectrum) resistance against powdery mildew fungi. EHM-specific localization of RPW8.2 suggests the existence of an EHM-oriented protein/membrane trafficking pathway during EHM biogenesis. However, the importance of this specific trafficking pathway for host defense has not been evaluated via a genetic approach without affecting other trafficking pathways. Here, we report that expression of EHM-oriented, nonfunctional RPW8.2 chimeric proteins exerts dominant negative effect over functional RPW8.2 and potentially over other EHM-localized defense proteins, thereby compromising both RPW8.2-mediated and basal resistance to powdery mildew. Thus, our results highlight the importance of the EHM-oriented protein/membrane trafficking pathway for host resistance against haustorium-forming pathogens such as powdery mildew fungi.

  10. A Transient Expression System for the Functional Assessment of Early Response Genes on the Powdery Mildew Infected Barley or Wheat Leaves

    Institute of Scientific and Technical Information of China (English)

    LI Ai-li

    2003-01-01

    The principle and the basic steps of the transient assay system for the functional assessment ofearly response genes on the powdery mildew infected barley or wheat leaves were summarized in brief. The development of this technology and its extensive application were reviewed. Future studies on this approach wererecommended in this paper.

  11. Oidium neolycopersici: Intra-specific variability inferred from AFLP analysis and relationship with closely related powdery mildew fungi infecting various plant species

    NARCIS (Netherlands)

    Jankovics, T.; Bai, Y.; Kovacs, G.M.; Bardin, M.; Nicot, P.C.; Toyoda, H.; Matsuda, Y.; Niks, R.E.; Kiss, L.

    2008-01-01

    Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polym

  12. Control of powdery mildew on glasshouse-grown roses and tomatoes in the Netherlands using anhydrous milk fat and soybean oil emulsions

    NARCIS (Netherlands)

    Wurms, K.V.; Hofland-Zijlstra, Jantineke

    2015-01-01

    Powdery mildew (PM) is a very serious disease affecting glasshouse-grown roses and tomatoes in the Netherlands. Control is limited because of resistance to existing fungicides. Anhydrous milk fat (AMF) and soybean oil (SBO) emulsions were evaluated for control of PM in roses and tomatoes. Both AM

  13. Development of diagnostic PCR markers closely linked to the tomato powdery mildew resistance gene Ol-1 on chromosome 6 of tomato

    NARCIS (Netherlands)

    Huang, C.C.; Cui, Y.Y.; Weng, C.R.; Zabel, P.; Lindhout, P.

    2000-01-01

    Lycopersicon hirsutum G1.1560 is a wild accession of tomato that shows resistance to Oidium lycopersicum, a frequently occurring tomato powdery mildew. This resistance is largely controlled by an incompletely dominant gene Ol-1 near the Aps-1 locus in the vicinity of the resistance genes Mi and

  14. Codominant PCR-based markers and candidate genes for powdery mildew resistance in melon (Cucumis melo L.).

    Science.gov (United States)

    Yuste-Lisbona, Fernando J; Capel, Carmen; Gómez-Guillamón, María L; Capel, Juan; López-Sesé, Ana I; Lozano, Rafael

    2011-03-01

    Powdery mildew caused by Podosphaera xanthii is a major disease in melon crops, and races 1, 2, and 5 of this fungus are those that occur most frequently in southern Europe. The genotype TGR-1551 bears a dominant gene that provides resistance to these three races of P. xanthii. By combining bulked segregant analysis and amplified fragment length polymorphisms (AFLP), we identified eight markers linked to this dominant gene. Cloning and sequencing of the selected AFLP fragments allowed the development of six codominant PCR-based markers which mapped on the linkage group (LG) V. Sequence analysis of these markers led to the identification of two resistance-like genes, MRGH5 and MRGH63, belonging to the nucleotide binding site (NBS)-leucine-rich repeat (LRR) gene family. Quantitative trait loci (QTL) analysis detected two QTLs, Pm-R1-2 and Pm-R5, the former significantly associated with the resistance to races 1 and 2 (LOD score of 26.5 and 33.3; 53.6 and 61.9% of phenotypic variation, respectively), and the latter with resistance to race 5 (LOD score of 36.8; 65.5% of phenotypic variation), which have been found to be colocalized with the MRGH5 and MRGH63 genes, respectively. The results suggest that the cluster of NBS-LRR genes identified in LG V harbours candidate genes for resistance to races 1, 2, and 5 of P. xanthii. The evaluation of other resistant germplasm showed that the codominant markers here reported are also linked to the Pm-w resistance gene carried by the accession 'WMR-29' proving their usefulness as genotyping tools in melon breeding programmes.

  15. Protection of wheat against leaf and stem rust and powdery mildew diseases by inhibition of polyamine metabolism

    Science.gov (United States)

    Weinstein, L. H.; Osmeloski, J. F.; Wettlaufer, S. H.; Galston, A. W.

    1987-01-01

    In higher plants, polyamines arise from arginine by one of two pathways: via ornithine and ornithine decarboxylase or via agmatine and arginine decarboxylase but in fungi, only the ornithine decarboxylase pathway is present. Since polyamines are required for normal growth of microorganisms and plants and since the ornithine pathway can be irreversibly blocked by alpha-difluoromethylornithine (DFMO) which has no effect on arginine decarboxylase, fungal infection of green plants might be controlled by the site-directed use of such a specific metabolic inhibitor. DFMO at relatively low concentrations provided effective control of the three biotrophic fungal pathogens studied, Puccinia recondita (leaf rust), P. graminis f. sp. tritici (stem rust), and Erysiphe graminis (powdery mildew) on wheat (Triticum aestivum L.) Effective control of infection by leaf or stem rust fungi was obtained with sprays of DFMO that ranged from about 0.01 to 0.20 mM in experiments where the inhibitor was applied after spore inoculation. The powdery mildew fungus was somewhat more tolerant of DFMO, but good control of the pathogen was obtained at less than 1.0 mM. In general, application of DFMO after spore inoculation was more effective than application before inoculation. Less control was obtained following treatment with alpha-difluoromethylarginine (DFMA) but the relatively high degree of control obtained raises the possibility of a DFMA to DFMO conversion by arginase.

  16. Molecular cytogenetic identification of a wheat-rye 1R addition line with multiple spikelets and resistance to powdery mildew.

    Science.gov (United States)

    Yang, Wujuan; Wang, Changyou; Chen, Chunhuan; Wang, Yajuan; Zhang, Hong; Liu, Xinlun; Ji, Wanquan

    2016-04-01

    Alien addition lines are important for transferring useful genes from alien species into common wheat. Rye is an important and valuable gene resource for improving wheat disease resistance, yield, and environment adaptation. A new wheat-rye addition line, N9436B, was developed from the progeny of the cross of common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) cultivar Shaanmai 611 and rye (Secale cereal L., 2n = 2x = 14, RR) accession Austrian rye. We characterized this new line by cytology, genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), molecular markers, and disease resistance screening. N9436B was stable in morphology and cytology, with a chromosome composition of 2n = 42 + 2t = 22II. GISH investigations showed that this line contained two rye chromosomes. GISH, FISH, and molecular maker identification suggested that the introduced R chromosome and the missing wheat chromosome arms were 1R chromosome and 2DL chromosome arm, respectively. N9436B exhibited 30-37 spikelets per spike and a high level of resistance to powdery mildew (Blumeria graminis f. sp. tritici, Bgt) isolate E09 at the seedling stage. N9436B was cytologically stable, had the trait of multiple spikelets, and was resistant to powdery mildew; this line should thus be useful in wheat improvement.

  17. Protection of wheat against leaf and stem rust and powdery mildew diseases by inhibition of polyamine metabolism.

    Science.gov (United States)

    Weinstein, L H; Osmeloski, J F; Wettlaufer, S H; Galston, A W

    1987-01-01

    In higher plants, polyamines arise from arginine by one of two pathways: via ornithine and ornithine decarboxylase or via agmatine and arginine decarboxylase but in fungi, only the ornithine decarboxylase pathway is present. Since polyamines are required for normal growth of microorganisms and plants and since the ornithine pathway can be irreversibly blocked by alpha-difluoromethylornithine (DFMO) which has no effect on arginine decarboxylase, fungal infection of green plants might be controlled by the site-directed use of such a specific metabolic inhibitor. DFMO at relatively low concentrations provided effective control of the three biotrophic fungal pathogens studied, Puccinia recondita (leaf rust), P. graminis f. sp. tritici (stem rust), and Erysiphe graminis (powdery mildew) on wheat (Triticum aestivum L.) Effective control of infection by leaf or stem rust fungi was obtained with sprays of DFMO that ranged from about 0.01 to 0.20 mM in experiments where the inhibitor was applied after spore inoculation. The powdery mildew fungus was somewhat more tolerant of DFMO, but good control of the pathogen was obtained at less than 1.0 mM. In general, application of DFMO after spore inoculation was more effective than application before inoculation. Less control was obtained following treatment with alpha-difluoromethylarginine (DFMA) but the relatively high degree of control obtained raises the possibility of a DFMA to DFMO conversion by arginase.

  18. Quantification of the Changes in Potent Wine Odorants as Induced by Bunch Rot (Botrytis cinerea) and Powdery Mildew (Erysiphe necator).

    Science.gov (United States)

    Lopez Pinar, Angela; Rauhut, Doris; Ruehl, Ernst; Buettner, Andrea

    2017-01-01

    Fungal infections are detrimental for viticulture since they may reduce harvest yield and wine quality. This study aimed to characterize the effects of bunch rot and powdery mildew on wine aroma by quantification of representative aroma compounds using Stable Isotope Dilution Analysis (SIDA). For this purpose, samples affected to a high degree by each fungus were compared with a healthy sample in each case; to this aim, the respective samples were collected and processed applying identical conditions. Thereby, the effects of bunch rot were studied in three different grape varieties: White Riesling, Red Riesling and Gewürztraminer whereas the influence of powdery mildew was studied on the hybrid Gm 8622-3. Analyses revealed that both fungal diseases caused significant changes in the concentration of most target compounds. Thereby, the greatest effects were increases in the concentration of phenylacetic acid, acetic acid and γ-decalactone for both fungi and all grape varieties. Regarding other compounds, however, inconsistent effects of bunch rot were observed for the three varieties studied.

  19. Quantification of the Changes in Potent Wine Odorants as Induced by Bunch Rot (Botrytis cinerea and Powdery Mildew (Erysiphe necator

    Directory of Open Access Journals (Sweden)

    Angela Lopez Pinar

    2017-08-01

    Full Text Available Fungal infections are detrimental for viticulture since they may reduce harvest yield and wine quality. This study aimed to characterize the effects of bunch rot and powdery mildew on wine aroma by quantification of representative aroma compounds using Stable Isotope Dilution Analysis (SIDA. For this purpose, samples affected to a high degree by each fungus were compared with a healthy sample in each case; to this aim, the respective samples were collected and processed applying identical conditions. Thereby, the effects of bunch rot were studied in three different grape varieties: White Riesling, Red Riesling and Gewürztraminer whereas the influence of powdery mildew was studied on the hybrid Gm 8622-3. Analyses revealed that both fungal diseases caused significant changes in the concentration of most target compounds. Thereby, the greatest effects were increases in the concentration of phenylacetic acid, acetic acid and γ-decalactone for both fungi and all grape varieties. Regarding other compounds, however, inconsistent effects of bunch rot were observed for the three varieties studied.

  20. QTL Analysis and Nested Association Mapping for Adult Plant Resistance to Powdery Mildew in Two Bread Wheat Populations

    Directory of Open Access Journals (Sweden)

    Yan Ren

    2017-07-01

    Full Text Available CIMMYT wheat (Triticum aestivum L. lines Francolin#1 and Quaiu#3 displayed effective and stable adult plant resistance (APR to Chinese Blumeria graminis f. sp. tritici isolates in the field. To elucidate their genetic basis of resistance, two recombinant inbred line (RIL populations of their crosses with Avocet, the susceptible parent, were phenotyped in Zhengzhou and Shangqiu in the 2014–2015 and 2015–2016 cropping seasons. These populations were also genotyped with SSR (simple sequence repeat markers and DArT (diversity arrays technology markers. Two common significant quantitative trait loci (QTL on wheat chromosomes 1BL and 4BL were detected in both populations by joint and individual inclusive composite interval mapping, explaining 20.3–28.7% and 9.6–15.9% of the phenotypic variance in Avocet × Francolin#1 and 4.8–11.5% and 10.8–18.9% in Avocet × Quaiu#3, respectively. Additional QTL were mapped on chromosomes 1DL and 5BL in Avocet × Francolin#1 and on 2DL and 6BS in Avocet × Quaiu#3. Among these, QPm.heau-1DL is probably a novel APR gene contributing 6.1–8.5% of total phenotypic variance. The QTL on 1BL corresponds to the pleiotropic multi-pathogen resistance gene Yr29/Lr46/Pm39, whereas the QTL on 2DL maps to a similar region where stripe rust resistance gene Yr54 is located. The QTL identified can potentially be used for the improvement of powdery mildew and rust resistance in wheat breeding.

  1. Transcriptome analysis of genes related to resistance against powdery mildew in wheat-Thinopyrum alien addition disomic line germplasm SN6306.

    Science.gov (United States)

    Li, Quanquan; Niu, Zubiao; Bao, Yinguang; Tian, Qiuju; Wang, Honggang; Kong, Lingrang; Feng, Deshun

    2016-09-15

    Wheat powdery mildew, which is mainly caused by Blumeria graminis f. sp. tritici (Bgt), seriously damages wheat production. The wheat-Thinopyrum intermedium alien addition disomic line germplasm SN6306, being one of the important sources of genes for wheat resistance, is highly resistant to Bgt E09 and to many other powdery mildew physiological races. However, knowledge on the resistance mechanism of SN6306 remains limited. Our study employed high-throughput RNA sequencing based on next-generation sequencing technology (Illumina) to obtain an overview of the transcriptome characteristics of SN6306 and its parent wheat Yannong 15 (YN15) during Bgt infection. The sequencing generated 104,773 unigenes, 9909 of which showed varied expression levels. Among the 9909 unigenes, 1678 unigenes showed 0 reads in YN15. The expression levels in Bgt-inoculated SN6306 and YN15 of exactly 39 unigenes that showed 0 or considerably low reads in YN15 were validated to identify the genes involved in Bgt resistance. Among the 39 unigenes, 12 unigenes were upregulated in SN6306 by 3-45 times. These unigenes mainly encoded kinase, synthase, proteases, and signal transduction proteins, which may play an important role in the resistance against Bgt. To confirm whether the unigenes that showed 0 reads in YN15 are really unique to SN6306, 8 unigenes were cloned and sequenced. Results showed that the selected unigenes are more similar to SN6306 and Th. intermedium than to the wheat cultivar YN15. The sequencing results further confirmed that the unigenes showing 0 reads in YN15 are unique to SN6306 and are most likely derived from Th. intermedium (Host) Nevski. Thus, the genes from Th. intermedium most probably conferred the resistance of SN6306 to Bgt.

  2. Towards a more sustainable agriculture: wheat mycorrhization to protect against powdery mildew.

    Science.gov (United States)

    Mustafa, G; Tisserant, B; Randoux, B; Fontaine, J; Reignault, Ph; Sahraoui, A Lounes-Hadj

    2013-01-01

    One of the means to reduce the use of pesticides, which are harmful for humans and the environment, is the development of alternative methods to control crop diseases. In this context, arbuscular mycorrhizal inoculation possesses a great potential for crop production by a more sustainable agriculture. Our work aims to (i) determine the optimal conditions for wheat mycorrhization (ii) study the impact of arbuscular mycorrhizal inoculation on a foliar disease of wheat, powdery mildew (Blumeria graminis f.sp. tritici, Bgt), (iii) evaluate the stimulation of natural defences of wheat (Triticuma estivum). Therefore, this work consisted firstly of defining the parameters, affecting the establishment of wheat mycorrhization, such as: phosphorus concentration (62, 12.5, 6.2 mg/L), culture time (4, 5, 6, 7 weeks), arbuscular mycorrhizal species used as an inoculum (Rhizophagus irregularis (Ri), Glomus masseae (Gm) and the mixture of (Ri+Gm)) and wheat cultivars (Orvantis and Lord, sensitive and moderately resistant to Bgt, respectively). Secondly, the protective effect of mycorrhizal inoculation against Bgt was estimated by comparing infection rates of wheat seedlings subjected and non-subjected to AMF. Finally, to better understand the biochemical mechanisms involved in the protection, two enzymatic activities described as defense markers [lipoxygenase (LOX) and peroxidase (POX)] were also assessed. Extensive mycorrhization (about 31%) was obtained at P/5 concentration (12.5 mg/L) when wheat plants were 6 weeks old. The highest colonization rate was obtained when wheat was inoculated with Gm compared to SZE and Ri. The higher resistance level of Lord wheat cultivar against Bgt did not affect the mycorrhizal rate compared to the more susceptible cultivar Orvantis. Our work showed a significant protection level in mycorrhizal (M) wheat plants against Bgt, estimated to about 25 and 43% with Ri and SZE respectively compared to non-mycorrhizal (NM) Orvantis plants. The

  3. Development and Identification of Wheat Haynaldia villosa 6DL/6VS Translocation Lines with Powdery Mildew Resistance

    Institute of Scientific and Technical Information of China (English)

    Li Hui; Chen Xiao; Xin Zhiyong; Ma Youzhi; Xu Huijun

    2000-01-01

    Wheat-H. villosa 6DL/6VS translocation lines, Pm97033, Pm97034 and Pm97035 developed by(TH3/4 ×Wan7107)F1 young embryo and anther culture, were evaluated by powdery mildew resistance test, cytogenetic analysis, biochemical analysis, and in situ hybridization respectively. Pm97033 and its hybrids crossing with susceptible cultivar Wan7107, 6D/6V substitution line and double ditelocentric lines (DDT) of Chinese Spring(C S)6A, 6B and 6D were all immune to powdery mildew through the growing period. It was with the somatic chromosome number of 42 and twenty-one bivalents at M I in pollen mother cells (PMCs M I ). The configurations at pMCs M I in hybrids F1 of Pm97033 with either susceptible cultivar or 6D/6V substitution line were 21 biva lents. In hybrids F1 between Pm97033 and C S 6A, 6B DDT, twenty bivalents and one allo-trivalent (t I t)composing of one univalent and two telocentric chromosomes were observed at PMCs M I . The configuration between Pm97033 and C S 6D DDT was twenty bivalents, one allo-bivalent (I t)and one telocentric chromosome. The results of cytogenetic analysis showed that Pm97033 was a translocation line , and the translocation was related to chromosome 6D. The results of in situ hybridization between probe labeled with biotin of H. villosa total DNA and the chromosomes showed that the three lines were all Robertsonian translocation lines. Glutamate oxaloacetate transaminase (GOT)isozyrme analyses showed that the translocation lines expressed the same pattern with C S,and without the specific band of 6VL of H. villas compared with substitution line and addition line. In α-zone of gliadin-2 pattern, all lines resistant to powdery mildew expressed an identical specific band encoded by the gene located on 6VS of H. villosa. All the cytogenetic and biochemical analysis confirmed that Pm97033, etc. were 6DL/6VS translocation lines with the substitution of 6VS for 6DS.

  4. Mla- and Rom1-mediated control of microRNA398 and chloroplast copper/zinc superoxide dismutase regulates cell death in response to the barley powdery mildew fungus

    Science.gov (United States)

    Barley Mla (Mildew resistance locus a) confers allele-specific interactions with natural variants of the ascomycete fungus, Blumeria graminis f. sp. hordei (Bgh), causal agent of powdery mildew disease. Significant reprogramming of host gene expression occurs upon infection by this obligate biotrop...

  5. InDel Markers for Identification of Cucumber Powdery Mildew Resistance%用于黄瓜白粉病抗性鉴定的InDel标记

    Institute of Scientific and Technical Information of China (English)

    聂京涛; 李晓丹; 姚永康; 潘俊松; 何欢乐; 刘士辉; 蔡润

    2015-01-01

    The co-dominant InDel markers were successfully explored based on the insertion-deletion (InDel)mutation in the major gene/QTL conferring powdery mildew resistance in cucumber(Cucumis sativus L.). The InDel marker InDel-MLO1 was co-segregated with the major gene for powdery mildew resistance through linkage analysis. Known of powdery mildew resistance phenotype,24 cucumber lines originated from various geographical regions of the world were tested by the InDel marker. The results showed that the genotypes of InDel-MLO1 were consistent with their resistance phenotypes in 21 cucumber lines,which indicated that this causal InDel mutation for powdery mildew resistance occurred frequently during the evolution and domestication of cucumber. Therefore,our finding confirmed that the InDel marker is very useful for identification of cucumber powdery mildew resistance and molecular marker-assisted breeding for most of the cucumber lines,and thus,the process of powdery mildew resistance breeding in cucumber will be accelerated.%根据黄瓜白粉病抗性主效基因/QTL的插入/缺失突变,将其设计成共显性的InDel分子标记。通过群体连锁分析,发现InDel-MLO1标记与黄瓜白粉病抗性主效基因共分离。应用该标记对24份来自世界各地且白粉病抗性已知的黄瓜材料进行抗性验证,21份材料的抗性表型与标记的带型一致,说明在黄瓜进化和驯化过程中,造成抗病表型的该插入/缺失突变发生普遍。因此,该InDel标记适合于大多数黄瓜材料的白粉病抗性鉴定和分子标记辅助育种,从而加快黄瓜白粉病抗病育种的进程。

  6. Single-cell transcript profiling of barley attacked by the powdery mildew fungus

    DEFF Research Database (Denmark)

    Gjetting, Torben; Hagedorn, Peter; Schweizer, Patrick

    2007-01-01

    attacked at the same time may resist fungal penetration. To date, the mixed cellular responses seen even in susceptible host leaves have made it difficult to relate induced changes in gene expression to resistance or susceptibility in bulk leaf samples. By microextraction of cell-specific m......RNA and subsequent cDNA array analysis, we have successfully obtained separate gene expression profiles for specific mildew-resistant and -infected barley cells. Thus, for the first time, it is possible to identify genes that are specifically regulated in infected cells and, presumably, involved in fungal...... establishment. Further, although much is understood about the genetic basis of effective papilla resistance associated with mutant mlo barley, we provide here the first evidence for gene regulation associated with effective papilla-based nonspecific resistance expressed in nominally "susceptible" wild...

  7. Observed and predicted changes in virulence gene frequencies at 11 loci in a local barley powdery mildew population

    DEFF Research Database (Denmark)

    Hovmøller, M.S.; Munk, L.; Østergård, H.

    1993-01-01

    a survey comprising 11 virulence loc. Predictions were based on a model where selection forces were estimated through detailed mapping in the local area of host cultivars and their resistance genes, and taking into account the changes in distribution of host cultivars during the year caused by growth......The aim of the present study was to investigate observed and predicted changes in virulence gene frequencies in a local aerial powdery mildew population subject to selection by different host cultivars in a local barley area. Observed changes were based on genotypic frequencies obtained through...... with a constant distribution of host cultivars. Significant changes in gene frequencies were observed for virulence genes subject to strong direct selection as well as for genes subject mainly to indirect selection (hitchhiking). These patterns of changes were generally as predicted from the model. The influence...

  8. Increased callose deposition in plants lacking DYNAMIN-RELATED PROTEIN 2B is dependent upon POWDERY MILDEW RESISTANT 4.

    Science.gov (United States)

    Leslie, Michelle E; Rogers, Sean W; Heese, Antje

    2016-11-01

    Callose deposition within the cell wall is a well-documented plant immune response to pathogenic organisms as well as to pathogen-/microbe- associated molecular patterns (P/MAMPs). However, the molecular mechanisms that modulate pathogen-induced callose deposition are less understood. We reported previously that Arabidopsis plants lacking the vesicle trafficking component DYNAMIN-RELATED PROTEIN 2B (DRP2B) display increased callose deposition in response to the PAMP flg22. Here, we show that increased number of flg22-induced callose deposits in drp2b leaves is fully dependent on the callose synthase POWDERY MILDEW RESISTANT 4 (PMR4). We propose that in addition to functioning in flg22-induced endocytosis of the plant receptor, FLAGELLIN SENSING 2, DRP2B may regulate the trafficking of proteins involved in callose synthesis, such as PMR4, and/or callose degradation.

  9. Defence reactions of plants to fungal pathogens: principles and perspectives, using powdery mildew on cereals as an example

    Science.gov (United States)

    Heitefuss, Rudolf

    2001-06-01

    Diseases of crop plants may lead to considerable yield losses. To control fungal diseases, fungicides are used extensively in present-day agricultural production. In order to reduce such external inputs, cultivars with natural resistance to important fungal pathogens are recommended in systems of integrated plant protection. Basic research, including genetics and molecular methods, is required to elucidate the mechanisms by which plants react to an attack by fungal pathogens and successfully defend themselves. This review examines our knowledge with respect to the multicomponent systems of resistance in plants, using powdery mildew on barley as an example. In addition, the question is adressed whether systemic acquired resistance and plants with transgenic resistance may be utilized in future plant protection strategies.

  10. Chromosome substitutions in progeny of hybrids Triticum aestivum x Triticum timopheevii resistant to brown rust and powdery mildew

    Energy Technology Data Exchange (ETDEWEB)

    Badaeva, E.D. [Engelhardt Institute of Molecular Biology, Moscow (Russian Federation); Badaev, N.S. [Bioengineering Center, Moscow (Russian Federation); Enno, T.M.; Peusha, H.O. [Institute of Experimental Biology, Moscow (Russian Federation); Zeller, F.J. [Institut fuer Pflanzenbau und Pflanzenzuechtung, Muenchen (Germany)

    1995-01-01

    By the C-banding technique, chromosome analysis of introgressive wheat lines derived from the tetraploid species T. timopheevii and T. militinae, with complex immunity to pathogens, was performed. It is shown that all hybrid lines possess genetic material of T. timopheevii and are stable in chromosome number (2n = 6x = 42) and composition. In the lines studied, the number of substitutions per genome varied from one to three; variation in the spectrum of chromosome substitutions was observed. Karyotypes of lines 146-155-T, SMT 30, SMT 34, SMT 37, and SMT 45, resistant to brown rust and powdery mildew, had one common chromosome substitution 6B(6G). It is suggested that the resistance to pathogens of these lines is determined by chromosome 6G of T. timopheevii.

  11. Comparison of mobile and stationary spore-sampling techniques for estimating virulence frequencies in aerial barley powdery mildew populations

    DEFF Research Database (Denmark)

    Hovmøller, M.S.; Munk, L.; Østergård, Hanne

    1995-01-01

    Gene frequencies in samples of aerial populations of barley powdery mildew (Erysiphe graminis f.sp. hordei), which were collected in adjacent barley areas and in successive periods of time, were compared using mobile and stationary sampling techniques. Stationary samples were collected from trap...... by the stationary technique will mainly reflect the source varieties present in the local area, whereas samples collected by the mobile spore trap will mainly reflect sources close to the sampling route. Therefore, sampling sites as well as sampling routes should be defined such that source varieties...... plants in three periods within 1 week at a distance of more than 1000 m from the nearest barley field. At four dates within the same 8-day period, other samples were collected by a mobile spore trap along four sampling routes of a total distance of 130 km around the stationary stand of exposure...

  12. Screening extracts of Achyranthes japonica and Rumex crispus for activity against various plant pathogenic fungi and control of powdery mildew.

    Science.gov (United States)

    Kim, Jin-Cheol; Choi, Gyung Ja; Lee, Seon-Woo; Kim, Jin-Seog; Chung, Kyu Young; Cho, Kwang Yun

    2004-08-01

    Methanol extracts of fresh materials of 183 plants were screened for in vivo antifungal activity against Magnaporthe grisea, Corticium sasaki, Botrytis cinerea, Phytophthora infestans, Puccinia recondita and Erysiphe graminis f sp hordei. Among them, 33 plant extracts showed disease-control efficacy of more than 90% against at least one of six plant diseases. The methanol extracts of Achyranthes japonica (whole plant) and Rumex crispus (roots) at concentrations greater than 11 g fresh weight of plant tissue per litre of aqueous Tween 20 solution effectively controlled the development of barley powdery mildew caused by E graminis f sp hordei in an in vivo assay using plant seedlings. At a concentration of 300 g fresh weight of plant tissue per litre of Tween 20 solution, the two extracts were as efficient as the fungicide fenarimol (30 mg litre(-1)) and more active than the fungicide polyoxin B (100 and 33 mg litre(-1)) against Sphaerotheca fuliginea on cucumber plants in glasshouse trials.

  13. Evaluation of Inbred Line about Seed-used Pumpkin Resistances to the Powdery Mildew Disease%籽用南瓜优质自交系白粉病抗性初步评价

    Institute of Scientific and Technical Information of China (English)

    赵茜; 徐丽珍

    2012-01-01

    In order to select good resistant inbred lines of seed-used pumpkin to powdery mildew disease,30 kinds inbred lines of seed-used pumpkin for resistance powdery mildew disease were identified in the natural condition.The results showed that there were no immune and high resistant types.There two resistant types,accounting for 6.7% of all appraisal inbred-lines,eleven of moderate resistant material,accounting for 36.7% and 17 susceptible types,accounting for 56.7%.The difference of seed-used pumpkin for resistance powdery mildew disease was significantly among inbred-lines.%为了筛选出优质的籽用南瓜白粉病的抗性自交系,在自然发病条件下,鉴定了30份籽用南瓜自交系白粉病的抗病性。结果表明:无免疫和高抗类型;抗病类型为2份,占所有鉴定自交系的6.7%;中抗类型为11份,占所有鉴定自交系的36.7%;其余为感病类型17份,占所有鉴定自交系的56.7%。籽用南瓜自交系对白粉病的抗性都存在显著差异。

  14. Functional characterization of the powdery mildew susceptibility gene SmMLO1 in eggplant (Solanum melongena L.).

    Science.gov (United States)

    Bracuto, Valentina; Appiano, Michela; Ricciardi, Luigi; Göl, Deniz; Visser, Richard G F; Bai, Yuling; Pavan, Stefano

    2017-01-09

    Eggplant (Solanum melongena L.) is one of the most important vegetables among the Solanaceae and can be a host to fungal species causing powdery mildew (PM) disease. Specific homologs of the plant Mildew Locus O (MLO) gene family are PM susceptibility factors, as their loss of function results in a recessive form of resistance known as mlo resistance. In a previous work, we isolated the eggplant MLO homolog SmMLO1. SmMLO1 is closely related to MLO susceptibility genes characterized in other plant species. However, it displays a peculiar non-synonymous substitution that leads to a T → M amino acid change at protein position 422, in correspondence of the MLO calmodulin-binding domain. In this study, we performed the functional characterization of SmMLO1. Transgenic overexpression of SmMLO1 in a tomato mlo mutant compromised resistance to the tomato PM pathogen Oidium neolycopersici, thus indicating that SmMLO1 is a PM susceptibility factor in eggplant. PM susceptibility was also restored by the transgenic expression of a synthetic gene, named s-SmMLO1, encoding a protein identical to SmMLO1, except for the presence of T at position 422. This indicates that the T → M polymorphism does not affect the protein role as PM susceptibility factor. Overall, the results of this work are of interest for the functional characterization of MLO proteins and the introduction of PM resistance in eggplant using reverse genetics.

  15. The occurrence and the chemical control of powdery mildew of Lagerstroemia indica Lina%紫薇白粉病的发生及药剂防治

    Institute of Scientific and Technical Information of China (English)

    苏秀梅

    2012-01-01

    This paper probed into the occurrence and the chemical control of powdery mildew of lagerstroemia indica as well as the effect of 7 caixin bactericides on powdery mildew through experiments.The results indicated that Xiansheng had the best effect when these bactericides were used alone and the mixture of Jiajituobujin and Siansheng worked the best when they were mixed.%7种杀菌剂单独喷施和混合喷施对紫薇白粉病的防治效果。结果表明:单独喷施一种杀菌剂时,仙生防效最好;混合喷施两种杀菌剂时,以甲基托布津+仙生防效最佳。

  16. Effect Study of Different Fungicides on Wheat Powdery Mildew%不同杀菌剂防治小麦白粉病药效研究

    Institute of Scientific and Technical Information of China (English)

    石晓慧; 章诚

    2013-01-01

    研究不同杀菌剂对小麦白粉病的防治效果,结果表明:25%丙环唑乳油、50%醚菌酯水分散粒剂对小麦白粉病的防治效果较好,平均防治效果分别达到84.72%、86.05%。%Effect of different fungicides on wheat powdery mildew was studied.The results showed that 25% propiconazole EC and 50%Kresoxim-methyl WG had better control effects on wheat powdery mildew ,the average control effect reached 84.72%,86.05%,respectively.

  17. The relationship between powdrey mildew (Sphaerotheca fuliginea) resistance and leaf chlorosis sensitivity in cucumber (Cucumis sativus) studied in single seed descent lines

    NARCIS (Netherlands)

    Zijlstra, S.; Jansen, R.C.; Groot, S.P.C.

    1995-01-01

    The genetic relation between powdery mildew resistance and sensitivity for leaf chlorosis of glasshouse cucumber was investigated. The powdery mildew resistant, leaf chlorosis sensitive hybrid variety 'Profito' was crossed with the powdery mildew susceptible, non chlorosis sensitive hybrid variety '

  18. Occurrence and Control Experiments on Powdery Mildew of Corylus heterophylla%平榛白粉病的发生与防治试验

    Institute of Scientific and Technical Information of China (English)

    王忠; 左慧

    2015-01-01

    论述了平榛白粉病的发病规律,利用不同浓度的代森铵、多菌灵、甲基托布津、三唑酮和百菌清药剂对平榛白粉病进行防治试验,比较了不同种类和不同浓度的药剂对平榛白粉病的防治效果。结果表明:平榛白粉病初期发病为5月下旬至6月初,发病高峰期为6月下旬至7月下旬;代森铵、甲基托布津、多菌灵、百菌清、三唑酮等药剂对平榛白粉病的防治均有不同程度的效果,以25%三唑酮可湿性粉剂防治效果最好,可达到80%以上。%The pathogenesis regularity on powdery mildew of Corylus heterophylla was discussed.Different concen-trations of dyson ammonium,carbendazim,thiophanate-methyl,triadimefon and chlorothalonil pesticides were used to control of powdery mildew C.heterophylla.Control effects of different types and concentrations on powdery mil-dew of C.heterophylla were compared.Result shows that early stage of powdery mildew of C.heterophylla is from late May to early June,the peak incidence is in late June to late July;dyson ammonium,thiophanate-methyl, carbendazim,chlorothalonil and triadimefon have effects with varying degrees;25% triadimefon WP can obtain the optimal control effect,being above 80%.

  19. E3 ubiquitin ligase gene CMPG1-V from Haynaldia villosa L. contributes to powdery mildew resistance in common wheat (Triticum aestivum L.).

    Science.gov (United States)

    Zhu, Yanfei; Li, Yingbo; Fei, Fei; Wang, Zongkuan; Wang, Wei; Cao, Aizhong; Liu, Yuan; Han, Shuang; Xing, Liping; Wang, Haiyan; Chen, Wei; Tang, Sanyuan; Huang, Xiahe; Shen, Qianhua; Xie, Qi; Wang, Xiue

    2015-10-01

    Powdery mildew is one of the most devastating wheat fungal diseases. A diploid wheat relative, Haynaldia villosa L., is highly resistant to powdery mildew, and its genetic resource of resistances, such as the Pm21 locus, is now widely used in wheat breeding. Here we report the cloning of a resistance gene from H. villosa, designated CMPG1-V, that encodes a U-box E3 ubiquitin ligase. Expression of the CMPG1-V gene was induced in the leaf and stem of H. villosa upon inoculation with Blumeria graminis f. sp. tritici (Bgt) fungus, and the presence of Pm21 is essential for its rapid induction of expression. CMPG1-V has conserved key residues for E3 ligase, and possesses E3 ligase activity in vitro and in vivo. CMPG1-V is localized in the nucleus, endoplasmic reticulum, plasma membrane and partially in trans-Golgi network/early endosome vesicles. Transgenic wheat over-expressing CMPG1-V showed improved broad-spectrum powdery mildew resistance at seedling and adult stages, associated with an increase in expression of salicylic acid-responsive genes, H2 O2 accumulation, and cell-wall protein cross-linking at the Bgt infection sites, and the expression of CMPG1-V in H. villosa was increased when treated with salicylic acid, abscisic acid and H2 O2 . These results indicate the involvement of E3 ligase in defense responses to Bgt fungus in wheat, particularly in broad-spectrum disease resistance, and suggest association of reactive oxidative species and the phytohormone pathway with CMPG1-V-mediated powdery mildew resistance.

  20. 伞房决明白粉病的初次报道%First report of powdery mildew caused by Oidium cassiae-siameae on Cassia corymbosa

    Institute of Scientific and Technical Information of China (English)

    赵桂华; 李德伟; 席刚俊

    2010-01-01

    Cassia corymbosa is an introduced ornamental shrub in the Yangtze River Delta area.Severe powdery mildew occurred on C.corymbosa from late August to mid-November.It caused early defoliation and some infected plants failed to survive in the following year.The powdery mildew is caused by Oidium cassiae-siameae.The pathogen did not develop teleomorph under field observation in the last three years.This is the first report of C.corymbosa,as a new host of powdery mildew caused by Oidium cassiae-siameae.This fungus is a newly reported species in mainland China.%伞房决明是长江三角洲地区的园林绿化木本植物,在每年8月下旬至11月中旬会发生严重的白粉病,造成提前落叶,导致次年部分植株死亡.该病由 Oidium cassiae-siameae 引起.经过3年多的野外观察,未发现有性世代.初次报道伞房决明为 Oidium cassiae-siameae 白粉菌的新寄主.此真菌为中国大陆的初次记载.

  1. Cloning of a novel phosphateserine aminotransferase gene from a Triticum aestivum-Elytrigia elongatum alien substitution line with resistance to powdery mildew

    Institute of Scientific and Technical Information of China (English)

    HE Daoyi; WANG Honggang

    2005-01-01

    Shannong 551, a T. aestivum-E. elongatum alien substitution line with resistance to powdery mildew, was inoculated with pathogenic spores of powdery mildew. The leaf samples were prepared 48 h after inoculation for scanning electron microscopy. The result showed that germination of spores and growth of young mycelia on leaves of Shannong 551 were suppressed at the early stage of infection. At the same time, RNAs were prepared from the leaves for the cloning of WRP1 and RPW2 by cDNA RDA and RACE technology. BLAST analysis of the sequences indicated that both WRP1 and RPW2 were novel genes. WRP1 contains no complete ORF. RPW2 contains the conserved structure domain of aminotransferase, and its DNA sequence shares high homology with genes of phosphateserine aminotransferase in many organisms. Therefore, it is speculated as a novel phosphateserine aminotransferase gene. The results of Northern blot suggested that expression of RPW2 occurred at the early stage of infection by powdery mildew. Southern blot using the probe of RPW2, in which there was strong hybridizing signals in both genome of Shannong 551 and E. elongatum, but not in those of Jinan 13 and Lumai No.5, indicated that RPW2 derived from the genome of E. elongatum.

  2. 黄瓜白粉病拮抗细菌 Bs-18的筛选与鉴定%Screening and Identification of Antagonistic Bacterium Bs-18 against Cucumber Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    孙淑琴; 杨秀荣; 田涛; 孙冰冰

    2015-01-01

    为筛选对黄瓜白粉病菌具有拮抗作用的生防菌株,从温室土壤样品中分离到细菌菌株692株。经室内平板拮抗性筛选和盆栽防治试验,筛选出菌株Bs-18对黄瓜白粉病具有良好的防治作用,盆栽防效达82.22%。对菌株Bs-18进行形态特征、生理生化特性和16 S rDNA测序分析,将其鉴定为解淀粉芽孢杆菌( Bacillus amyloliquefaciens)。%To obtain antagonistic bacteria for biocontrol of cucumber powdery mildew , 692 bacterial strains were isolated from different greenhouse soil samples .The strain Bs-18 , which had good inhibitory effect on cucumber powdery mildew with the control effect of 82 .22%, was screened out using plate confrontation method and pot test .Based on the morphological characteristics , physicochemical properties and 16 S rDNA sequence analysis , the strain Bs-18 was identified as Bacillus amyloliquefaciens.

  3. The Carbon/Nitrogen Regulator ARABIDOPSIS TOXICOS EN LEVADURA31 Controls Papilla Formation in Response to Powdery Mildew Fungi Penetration by Interacting with SYNTAXIN OF PLANTS121 in Arabidopsis1[W][OPEN

    Science.gov (United States)

    Maekawa, Shugo; Inada, Noriko; Yasuda, Shigetaka; Fukao, Yoichiro; Fujiwara, Masayuki; Sato, Takeo; Yamaguchi, Junji

    2014-01-01

    The carbon/nitrogen (C/N) balance of plants is not only required for growth and development but also plays an important role in basal immunity. However, the mechanisms that link C/N regulation and basal immunity are poorly understood. We previously demonstrated that the Arabidopsis (Arabidopsis thaliana) Arabidopsis Tóxicos en Levadura31 (ATL31) ubiquitin ligase, a regulator of the C/N response, positively regulates the defense response against bacterial pathogens. In this study, we identified the plasma membrane-localized soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor SYNTAXIN OF PLANTS121 (SYP121) as a novel ATL31 interactor. The syp121-1 loss-of-function mutant showed similar hypersensitivity to C/N stress conditions as the atl31 atl6 double mutant. SYP121 is essential for resistance to penetration by powdery mildew fungus and positively regulates the formation of cell wall appositions (papillae) at fungal entry sites. Microscopic analysis demonstrated that ATL31 was specifically localized around papillae. In addition, ATL31 overexpressors showed accelerated papilla formation, enhancing their resistance to penetration by powdery mildew fungus. Together, these data indicate that ATL31 plays an important role in connecting the C/N response with basal immunity by promoting papilla formation through its association with SYP121. PMID:24394775

  4. Genomic and metabolic traits endow Bacillus velezensis CC09 with a potential biocontrol agent in control of wheat powdery mildew disease.

    Science.gov (United States)

    Cai, Xun-Chao; Liu, Chang-Hong; Wang, Bao-Tong; Xue, Ya-Rong

    2017-03-01

    Bacillus velezensis CC09, which was isolated from healthy leaves of Cinnamomum camphora and previously identified as Bacillus amyloliquefaciens CC09, shows great potential as a new biocontrol agent, in control of many phytopathogenic diseases. To extend our understanding of the potential antifungal capacities, we did a whole genome analysis of strain CC09. Result shows that strain CC09 has a relatively large genome size (4.17Mb) with an average GC content of 46.1%, and 4021 predicted genes. Thirteen secondary metabolites encoding clusters have been identified within the genome of B. velezensis CC09 using genome mining technique. Data of comparative genomic analysis indicated that 3 of the clusters are conserved by all strains of B. velezensis, B. amyloliquefaciens and B. subtilis 168, 9 by B. velezensis and B. amyloliquefaciens, and 2 by all strains of B. velezensis. Another 2 clusters encoding NRPS (Non-Ribosomal Peptide Synthetases) and NRPS-TransATPKS (NRPS and trans-Acyl Transferase Polyketide Synthetases) respectively are observed only in 15 B. velezensis strains, which might lead to the synthesis of novel bioactive compounds and could be explored as antimicrobial agents in the future. These clusters endow B. velezensis CC09 with strong and broad antimicrobial activities, for example, in control of wheat powdery mildew disease. Moreover, our data further confirmed the taxonomy of strain CC09 is a member of B. velezensis rather than a strain of B. amyloliquefaciens based on core genome sequence analysis using phylogenomic approach.

  5. EDR2 negatively regulates salicylic acid-based defenses and cell death during powdery mildew infections of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Nishimura Marc

    2007-07-01

    Full Text Available Abstract Background The hypersensitive necrosis response (HR of resistant plants to avirulent pathogens is a form of programmed cell death in which the plant sacrifices a few cells under attack, restricting pathogen growth into adjacent healthy tissues. In spite of the importance of this defense response, relatively little is known about the plant components that execute the cell death program or about its regulation in response to pathogen attack. Results We isolated the edr2-6 mutant, an allele of the previously described edr2 mutants. We found that edr2-6 exhibited an exaggerated chlorosis and necrosis response to attack by three pathogens, two powdery mildew and one downy mildew species, but not in response to abiotic stresses or attack by the bacterial leaf speck pathogen. The chlorosis and necrosis did not spread beyond inoculated sites suggesting that EDR2 limits the initiation of cell death rather than its spread. The pathogen-induced chlorosis and necrosis of edr2-6 was correlated with a stimulation of the salicylic acid defense pathway and was suppressed in mutants deficient in salicylic acid signaling. EDR2 encodes a novel protein with a pleckstrin homology and a StAR transfer (START domain as well as a plant-specific domain of unknown function, DUF1336. The pleckstrin homology domain binds to phosphatidylinositol-4-phosphate in vitro and an EDR2:HA:GFP protein localizes to endoplasmic reticulum, plasma membrane and endosomes. Conclusion EDR2 acts as a negative regulator of cell death, specifically the cell death elicited by pathogen attack and mediated by the salicylic acid defense pathway. Phosphatidylinositol-4-phosphate may have a role in limiting cell death via its effect on EDR2. This role in cell death may be indirect, by helping to target EDR2 to the appropriate membrane, or it may play a more direct role.

  6. STUDY ON POWDERY MILDEW RESISTANCE TRANSFER FROM S. CEREALE L.cv. WEILING RYE INTO WHEAT%威岭栽培黑麦抗白粉病特性导入小麦的研究

    Institute of Scientific and Technical Information of China (English)

    张怀渝; 任正隆

    2007-01-01

    Weiling rye (S. cereale L.cv.),a Chinese dwarf rye,confers high powdery mildew(Erysiphe gramininis f.sp.tritici) in China. My8443,a wheat cultivars infecting seriously powdery mildew disease,was used as the female parent and Weiling rye was used as the donor of powdery mildew resistance in the study. A new wheat-rye translocation line,named No.147,was developed from BC2F6 progenies of wheat cultivars My8443 and Weiling rye to transfer the resistance from Weiling rye to common wheat. The powdery mildew resistance of No.147 and its parents were investigated in seedling and adult stages by artificially inoculating the mixture of advanced pathogenic races in room and field and the single pathogenic race in room. Improved Giemsa Cbanding technique and genomic in situ hybridization (GISH,Genomic in situ hybridization) were used to identify wheat and rye chromosomes. Acid polyacylamide gel electrophoresis(APAGE) separation of endosperm gliadin and simple sequence repeat(SSR) PCR amplification of 11 SCM-Se-cale cereale markers also were employed for 1RS confirmation in the study. The results showed that No.147 was a new 1BL/1RS wheat-rye chromosome translocation with high powdery mildew resistance derived from Weiling rye. The reason on the formation of the new wheat-rye chromosome translocation was analyzed. The utilizations of resistance gene resource derived from Chinese Weiling rye and the new 1BL/1RS translocation line in wheat genetics and breeding improvement were discussed in the paper.%威岭黑麦(Weiling rye)是一个高抗白粉病(Erysiphe gramininis,f.sp.tritici)的中国矮杆栽培黑麦.以Weiling rye作为白粉病抗源,高感白粉病小麦栽培品种My8443为母本,从Weiling rye与小麦My8443远缘杂交的BC2F6后代中鉴定出一个新的小麦-黑麦易位系No.147,以实现威岭黑麦白粉病抗性向普通栽培小麦的转移.No.147及其亲本的抗白粉病特性通过苗期和成株期优势生理小种混合接种和室内单生理小

  7. Alternative Fungicide Spraying for the Control of Powdery Mildew Caused by Sphaerotheca fusca on Greenhouse Watermelon (Citrullus lanatus

    Directory of Open Access Journals (Sweden)

    Hyo-Jung Kang

    2014-03-01

    Full Text Available Alternative spraying was developed using fungicides and potassium phosphonate to control watermelon powdery mildew (WPM caused by Sphaerotheca fusca under greenhouse condition. In 2010 trial, a total of 9 combinations of 6 fungicides which are legally registered in Korea and currently used on watermelon farms were tested for the control efficacy against WPM. Though the combination of chlorothalonil (Chl-myclobutanil (My-fenarimol (Fen-hexaconazole (Hex was the most effective (82.6% in the first-year trial, it had the problem that My, Fen and Hex have the same mode of action. Therefore, in the second-year trial to improve the fungicide combination and to reduce fungicide application, fungicides and potassium phosphonate (P combinations were tested for WPM control using 500 ppm aqueous potassium phosphonate solution which is both eco-friendly and showing different mode of action from the fungicides tested. The P-My-Fen-Hex applied at 10-day intervals provided relatively high control (75.6%, whereas Chl-My-Fen-P provided 31.8% control. To improve the control, fungicides and P were applied at 7-day intervals in the third-year trial. Though Chl-My-Fen-Hex provided the highest control (89.6%, P-My-Fen-Hex also provided relatively high control (83.5% compared to 65.9 % control with Chl-My-Fen-P, which suggests that Chl-My-Fen-Hex could be replaced with P-My-Fen-Hex for WPM control.

  8. Elemental micro-PIXE mapping of hypersensitive lesions in Lagenaria sphaerica (Cucurbitaceae) resistant to Sphaerotheca fuliginea (powdery mildew)

    Science.gov (United States)

    Weiersbye-Witkowski, I. M.; Przybylowicz, W. J.; Straker, C. J.; Mesjasz-Przybylowicz, J.

    1997-07-01

    Genotypes of the Southern African cucurbit, Lagenaria sphaerica, that are resistant to powdery-mildew ( Sphaerotheca fuliginea) exhibit foliar hypersensitive (HS) lesions on inoculation with this fungal pathogen. Elemental distributions across radially symmetrical HS lesions, surrounding unlesioned leaf tissue and uninoculated leaf tissue, were obtained using the true elemental imaging system (Dynamic Analysis) of the NAC Van de Graaff nuclear microprobe. Raster scans of 3 MeV protons were complemented by simultaneous PIXE and BS point analyses. The composition of cellulose (C 6H 10O 5) was used as constant matrix composition for scans, and the sample thickness was found from BS spectra. Si and elements heavier than Ca contributed to matrix composition within HS lesions and the locally elevated Ca raised the limits of detection for some trace metals of interest. In comparison to uninoculated tissue, inoculated tissue was characterised by higher overall concentrations of all measured elements except Cu. Fully developed, 6 day-old HS lesions and the surrounding tissue could be divided into five zones, centred on the fungal infection site. Each zone was characterized by distinct local elemental distributions (either depletion, or accumulation to potentially phytotoxic levels).

  9. Climate year type of wheat powdery mildew epidemics in Hebei Province of North China based on rule of thumb%基于经验法则的小麦白粉病气候年型分析

    Institute of Scientific and Technical Information of China (English)

    姚树然; 霍治国; 司丽丽

    2013-01-01

    温湿度条件是影响小麦白粉病发生流行的关键气象要素.应用河北省主麦区1987-2010年小麦白粉病资料和相应气象资料,利用合成分析和秩相关分析,筛选出影响小麦白粉病流行的关键气象因子;根据经验法则,利用小麦白粉病流行阶段的温度距平和湿度距平判别白粉病流行程度,并确定了白粉病流行的气候年型与指标.经历史回代,判别小麦白粉病流行程度准确率为84%,并进行了2011年、2012年的外延指标判别,准确率达100%,综合判断准确率在85%以上.该研究结果可为小麦白粉病影响评估与长期预报提供科学依据.%Temperature and humidity are the most important meteorological elements affecting the epidemics of wheat powdery mildew. Based on the wheat powdery mildew epidemics data in the main wheat production areas in Hebei Province in 1987-2010 and the related meteorological data , and by the methods of composite analysis and rank correlation analysis, the key meteorological factors affecting the wheat powdery mildew epidemics were set up. According to the rule of thumb, the epidemic degree of the powdery mildew was distinguished by the anomaly of temperature and the anomaly of humidity climate at different epidemic stages of the powdery mildew, and the year types and controlling factors of the powdery mildew epidemics were determined. From the validation of historical data, the general accordance ratio was 84% . By using the extrapolated controlling factors values of the powdery mildew epidemics in 2011 and 2012, the forecast accuracy was 100%. When integrated with the climate year types, the forecast accuracy was above 85%. Our results could provide scientific references for the assessment and long-term forecast of wheat powdery mildew epidemics.

  10. Do 14-3-3 proteins and plasma membrane H+-ATPases interact in the barley epidermis in response to the barley powdery mildew fungus?

    DEFF Research Database (Denmark)

    Finnie, C.; Andersen, C.H.; Borch, J.

    2002-01-01

    14-3-3 proteins form a family of highly conserved proteins with central roles in many eukaryotic signalling networks. In plants, they bind to and activate the plasma membrane H+-ATPase, creating a binding site for the phytotoxin fusicoccin. Barley 14-3-3 transcripts accumulate in the epidermis upon......+-ATPase. These effects are seen specifically in the inoculated epidermis and not in the whole leaf. We propose that 14-3-3 proteins are involved in an epidermis-specific response to the powdery mildew fungus, possibly via an activation of the plasma membrane H+-ATPase....

  11. Do 14-3-3 proteins and plasma membrane H+-AtPases interact in the barley epidermis in response to the barley powdery mildew fungus?

    DEFF Research Database (Denmark)

    Finni, Christine; Andersen, Claus H; Borch, Jonas

    2002-01-01

    14-3-3 proteins form a family of highly conserved proteins with central roles in many eukaryotic signalling networks. In plants, they bind to and activate the plasma membrane H+-ATPase, creating a binding site for the phytotoxin fusicoccin. Barley 14-3-3 transcripts accumulate in the epidermis upon......+-ATPase. These effects are seen specifically in the inoculated epidermis and not in the whole leaf. We propose that 14-3-3 proteins are involved in an epidermis-specific response to the powdery mildew fungus, possibly via an activation of the plasma membrane H+-ATPase....

  12. AvrPm2 encodes an RNase-like avirulence effector which is conserved in the two different specialized forms of wheat and rye powdery mildew fungus.

    Science.gov (United States)

    Praz, Coraline R; Bourras, Salim; Zeng, Fansong; Sánchez-Martín, Javier; Menardo, Fabrizio; Xue, Minfeng; Yang, Lijun; Roffler, Stefan; Böni, Rainer; Herren, Gerard; McNally, Kaitlin E; Ben-David, Roi; Parlange, Francis; Oberhaensli, Simone; Flückiger, Simon; Schäfer, Luisa K; Wicker, Thomas; Yu, Dazhao; Keller, Beat

    2017-02-01

    There is a large diversity of genetically defined resistance genes in bread wheat against the powdery mildew pathogen Blumeria graminis (B. g.) f. sp. tritici. Many confer race-specific resistance to this pathogen, but until now only the mildew avirulence gene AvrPm3(a2/f2) that is recognized by Pm3a/f was known molecularly. We performed map-based cloning and genome-wide association studies to isolate a candidate for the mildew avirulence gene AvrPm2. We then used transient expression assays in Nicotiana benthamiana to demonstrate specific and strong recognition of AvrPm2 by Pm2. The virulent AvrPm2 allele arose from a conserved 12 kb deletion, while there is no protein sequence diversity in the gene pool of avirulent B. g. tritici isolates. We found one polymorphic AvrPm2 allele in B. g. triticale and one orthologue in B. g. secalis and both are recognized by Pm2. AvrPm2 belongs to a small gene family encoding structurally conserved RNase-like effectors, including Avra13 from B. g. hordei, the cognate Avr of the barley resistance gene Mla13. These results demonstrate the conservation of functional avirulence genes in two cereal powdery mildews specialized on different hosts, thus providing a possible explanation for successful introgression of resistance genes from rye or other grass relatives to wheat.

  13. Identification of Powdery Mildew Resistant Genes based on SCAR Markers in Common Bean (Phaseolus vulgaris L.)%普通菜豆抗白粉病基因SCAR标记鉴定

    Institute of Scientific and Technical Information of China (English)

    吴星波; 郝俊杰; 张晓艳; 万述伟; 李红卫; 邵阳; 孙吉禄

    2013-01-01

    Eight SCAR primer combinations( SAU5, SS18, SF6Em3, SF12R9, SF13R10, SF18R7, SF18R15 and SMe1Em5) of common bean powdery mildew resistant genes were used to check the genome DNA of 78 common bean accessions. The SCAR primer pairs of SF12R9, SF13R10, SF18R7, SF18R15 and SMe1Em5 did not amplified target bands at all; SAU5 marker appeared in 52 accessions, SF6Em3 marker in 66 accessions, and SS18 marker in 76 accessions. 2~3 SCAR markers appeared in 76 accessions respectively. The types of powdery mildew resistant genes in each of the 78 accessions have been identified, and the accessions with pyramiding powdery mildew resistance genes were selected.%利用8个来自于普通菜豆抗白粉病基因SCAR 标记( SAU5、SS18、SF6Em3、SF12R9、SF13R10、SF18R7、SF18R15和SMe1Em5)引物组,对78份普通菜豆资源进行抗白粉病分子标记的鉴定。结果表明:在这78份资源中, SF12R9、SF13R10、SF18R7、SF18R15和SMe1Em5均无扩增带。有52份资源含有SAU5标记,66份资源含有SF6Em3标记,76份资源含有SS18标记。76份资源含有2~3个标记。该研究明确了78份参试菜豆资源所含的抗白粉病基因类型,并筛选出抗白粉病基因聚合体的参试菜豆资源。

  14. Calcium transport in protoplasts isolated from ml-o barley isolines resistant and susceptible to powdery mildew. [Hordeum vulgare L

    Energy Technology Data Exchange (ETDEWEB)

    Wrona, A.F.; Spanswick, R.M.; Aist, J.R. (Cornell Univ., Ithaca, NY (USA))

    1988-12-01

    Free cytoplasmic calcium has been postulated to play a role in preventing powdery mildew in a series of homozygous ml-o mutants of barley, Hordeum vulgare L. Protoplasts isolated from 7-day-old plants of the ml-o resistant-susceptible (R-S) barley isolines, Riso 5678/3* {times} Carlsberg II R and S, were used to test for differences in fluxes of Ca{sup 2+} across the plasmalemma. Greater influx or lesser efflux might account for a higher free cytosolic Ca{sup 2+} postulated to exist in ml-o R mutants. Uniform patterns of uptake were maintained for 3 hours from solutions of 0.2 and 2 millimolar Ca{sup 2+}. Washout curves of {sup 45}Ca{sup 2+} from R and S protoplasts revealed three compartments - presumed to represent release from the vacuole, organelles, and the cytoplasm (which included bound as well as free Ca{sup 2+}). Uptake and washout did not differ between isolines. On the basis of recent determinations of submicromolar levels of free cytoplasmic Ca{sup 2+} and their initial rates of {sup 45}ca-labeled Ca{sup 2+} uptake, they show that measurement of the unidirectional influx of Ca{sup 2+} across the plasmalemma is not feasible because the specific activity of the pool of free cytoplasmic calcium increases almost instantaneously to a level that would result in a significant, but unknown, efflux of label. Similarly, measurement of the efflux of Ca{sup 2+} across the plasmalemma is not possible since the activity of the pool of free cytoplasmic calcium is a factor of 350 smaller than the most rapid component of the washout experiment. This pool of cytoplasmic free Ca{sup 2+} will wash out too rapidly and be too small to detect under the conditions of these experiments.

  15. Ethylene and Abscisic Acid Signaling Pathways Differentially Influence Tomato Resistance to Combined Powdery Mildew and Salt Stress

    Science.gov (United States)

    Kissoudis, Christos; Seifi, Alireza; Yan, Zhe; Islam, A. T. M. Tanjimul; van der Schoot, Hanneke; van de Wiel, Clemens C. M.; Visser, Richard G. F.; van der Linden, C. G.; Bai, Yuling

    2017-01-01

    There is currently limited knowledge on the role of hormones in plants responses to combinations of abiotic and pathogen stress factors. This study focused on the response of tomato near-isogenic lines (NILs) that carry the Ol-1, ol-2, and Ol-4 loci, conferring resistance to tomato powdery mildew (PM) caused by Oidium neolycopersici, to combined PM and salt stress. These NILs were crossed with the notabilis (ABA-deficient), defenceless1 (JA-deficient), and epinastic (ET overproducer) tomato mutants to investigate possible roles of hormone signaling in response to combined stresses. In the NILs, marker genes for hormonal pathways showed differential expression patterns upon PM infection. The epinastic mutation resulted in breakdown of resistance in NIL-Ol-1 and NIL-ol-2. This was accompanied by reduced callose deposition, and was more pronounced under combined salt stress. The notabilis mutation resulted in H2O2 overproduction and reduced susceptibility to PM in NIL-Ol-1 under combined stress, but lead to higher plant growth reduction under salinity and combined stress. Resistance in NIL-ol-2 was compromised by the notabilis mutation, which was potentially caused by reduction of callose deposition. Under combined stress the compromised resistance in NIL-ol-2 was restored. PM resistance in NIL-Ol-4 remained robust across all mutant and treatment combinations. Hormone signaling is critical to the response to combined stress and PM, in terms of resistance and plant fitness. ABA appears to be at the crossroads of disease susceptibility/senescence and plant performance under combined stress These gained insights can aid in narrowing down targets for improving crop performance under stress combinations. PMID:28119708

  16. Critical yield-point model to estimate damage caused by brown spot and powdery mildew in barley

    Directory of Open Access Journals (Sweden)

    Lenita Agostinetto

    2014-06-01

    Full Text Available Barley (Hordeum vulgaris L. is the second most important winter crop in Southern Brazil. The excessive rainfall in this region during the crop-growing season increases the frequency and intensity of foliar fungal diseases. The research aimed to determine the damage function equations (DFE for the multiple pathosystem of barley brown spot and powdery mildew based on the relationship between grain yield and diseases intensity at different 'BRS Cauê' cultivar growth stages (GS during 2009 and 2010 growing seasons in Southern Brazil. The experiments were arranged in a randomized complete block design with nine treatments and four replicates. The disease gradients were generated by strobilurins and triazols fungicides rates and number of applications on barley cv. Cauê. The fungicide applications and disease incidence and severity assessments were performed at the 22, 31, 39, 45 and 56 plant GS. The DFE were obtained by variance analysis and linear regression between grain yield and diseases intensity. Significant and negative DFE were obtained and the damage coefficients (DC varied from 29.48 to 100.08 (2009 and from 36.08 to 113.57kg ha-1 (2010 for incidence, and from 219.5 to 6,276.6 (2009 and 102.3 to 5,292.5kg ha-1 (2010 for severity. The largest damage coefficients were obtained when diseases assessments were made on GS 22 and 31 on both growing seasons evaluated. DFE were used to calculate the economic damage threshold (EDT as a criterion to indicate the fungicide application moment to control the diseases in cultivars similar to 'BRS Cauê' in Southern Brazil.

  17. 盐城市小麦白粉病发生特点与防治对策%Patterns of Wheat Powdery Mildew Incidence in Yancheng City and Control Measures

    Institute of Scientific and Technical Information of China (English)

    黄婷婷; 陈永明; 林付根; 赵阳; 朱汉清; 王献

    2016-01-01

    小麦白粉病在江苏盐城麦区发生程度逐年加重,且已呈现常发态势。2015年本地小麦白粉病的发生特点,从小麦品种、气候条件、栽培方式等方面分析了重发原因,并提出了适时适量播种小麦,选用抗病品种,应用新型高效药剂以及采用“预防为主,抓小治早”的防治对策,以期为小麦白粉病的防治提供技术支持。%In recent years,there has been an increased incidence of wheat powdery mildew in Yancheng City of Jiangsu Province, which has become a recurrent disease.This paper elaborates patterns of its incidence in 2015 when it reached epidemic levels in Yancheng.The factors contributing to the high incidence of wheat powdery mildew are also discussed,which include the adopted wheat varieties being susceptible to powdery mildew,and the weather conditions and cultural practices favoring the development of this dis-ease.Finally,control measures are recommended,which should be effective in reducing the incidence of wheat powdery mildew in the future.

  18. Cucumber Powdery Mildew Pathogen Molecular Identification and Prevention Technology in Greenhouse in Huzhu%互助县温室大棚黄瓜白粉病病原菌分子鉴定及防治技术

    Institute of Scientific and Technical Information of China (English)

    白露佼; 蔡芳; 王鹏

    2015-01-01

    In order to ascertain types of cucumber powdery mildew pathogen, we investigated cucumber greenhouse in Huzhu county randomly,and collected plant tissue with disease, that acquisition of powdery mildew on the molecular iden-tification of powdery mildew pathogen suggested cucumber powdery mildew should be prevented primarily by chemical control methods as before, combined with high temperature.%为明确青海互助县温室大棚黄瓜白粉病病原菌的分类,随机调查种植黄瓜的日光温室,采集发病的植株组织,对白粉菌进行无性型扫描电镜观察和 DNA 提取。试验结果发现,互助县温室大棚内白粉菌为苍耳单囊白粉菌,生产中仍以化学防治为主,可结合高温闷棚灭菌。

  19. BP Neural Network Applications in the Incidence Forecast of Wheat Powdery Mildew in Xuchang%BP神经网络在许昌小麦白粉病发病趋势预测中的应用

    Institute of Scientific and Technical Information of China (English)

    李文峰

    2013-01-01

    通过统计河南省许昌小麦白粉病发生发展的气象生理指标及历年该病发生的资料,构建了小麦白粉病发病的气象预报模型。 BP神经网络小麦白粉病发病趋势预测模型应用了BP人工神经网络的函数映射能力并采用检验函数,拟合精度和预报精度都较高,经过对比优于多元线性回归模型,能很好地实现预期效果,对许昌小麦白粉病发病的预测预防工作具有一定的现实指导意义。%Using the physiological indicators and meteorological statistics of wheat powdery mildew over the years in Xuchang,Henan,the incidence of powdery mildew weather forecast model applied BP artificial neural network function mapping capability and test function. The fitting accuracy and forecast accuracy of BP neural network trend forecasting model for wheat powdery mildew is higher than the multiple linear regression model,which can well realize the desired effect. The study has a certain practical significance on Xuchang wheat powdery mildew disease prediction and prevention work.

  20. Inhibitive Effect of Bio-agents Against Powdery Mildew in Organic Cucumber%2种生物制剂对有机黄瓜白粉病的防治效果

    Institute of Scientific and Technical Information of China (English)

    唐洪杰; 魏萍; 姚夕敏; 徐玉恒; 马宗国; 沈庆斌

    2015-01-01

    白粉病是危害保护地黄瓜的重要病害之一,利用生物制剂防治黄瓜白粉病对满足有机农业标准(GB/T 19630—2011)要求具有重要实际意义。本研究比较了枯草芽孢杆菌可湿性粉剂(10亿cfu/g)和氨基寡糖素对有机黄瓜白粉病的防治效果。结果表明,在黄瓜白粉病发病较轻时(病情指数低于18.19),连续喷施枯草芽孢杆菌可湿性粉剂200倍稀释液和700倍稀释的氨基寡糖素能较好地控制白粉病的发生,防治效果分别达到87.2%~90.7%和52.5%~91.5%。建议在有机黄瓜未发生白粉病危害或白粉病病情指数小于10的情况下应用生物制剂进行防控。%Cucumber powdery mildew is one important diseases threatening to the facility cultivation of cucumber, biological agents application to control cucumber powdery mildew is significantly critical to meet organic agriculture standard (GB/T 19630——2011) requirements in the actual production. This study compared the effect of bacillus subtilis wettable powder (1 billion cfu/g) and amino-sugars for powdery mildew control in organic cucumber planting. Results showed that, continuous spraying 200 times bacillus subtilis wettable powder or 700 times amino-sugars could better control the occurrence of powdery mildew when the cucumber powdery mildew disease was lighter (disease index less than 18.19). And the control effects reached 87.2%-90.7% and 52.5%-91.5% respectively. It was advised that before the organic cucumber powdery mildew happened or the disease index less than 10 use biological agents to control organic cucumber powdery mildew.

  1. Effect of temperature, relative humidity and light on conidial germination of oak powdery mildew (Microsphaera alphitoides Griff. et Maubl. under controlled conditions

    Directory of Open Access Journals (Sweden)

    Pap P.

    2013-01-01

    Full Text Available The influence of temperature, humidity and light on the conidial germination and germ tube elongation of oak powdery mildew (Microsphaera alphitoides Griff. et Maubl. was studied in controlled conditions. The maximal germ tube length was attained at 25°C, whereas at lower and higher than optimal temperatures, germ tube growth was significantly lower. Germ tubes begin to develop at all values of relative humidity (10-100%, reaching the maximum length at 90%. The development of germ tubes was the most intense in full light and the lowest in total darkness. The artificial infection of floating leaves showed that an increasing age had an inhibitory effect on the mycelium development and spore formation. Since conidia play a crucial role in powdery mildew epidemiology, it is of particular importance to elucidate the influence of environmental factors in the complex relations that exist between the plant and its pathogen. [Projekat Ministarstva nauke Republike Srbije, br. 43007: Studying climate change and its influence on the environment: Impacts, adaptation and mitigation

  2. Loss of actin cytoskeletal function and EDS1 activity, in combination, severely compromises non-host resistance in Arabidopsis against wheat powdery mildew.

    Science.gov (United States)

    Yun, Byung-Wook; Atkinson, Helen A; Gaborit, Charlotte; Greenland, Andy; Read, Nick D; Pallas, Jacqueline A; Loake, Gary J

    2003-06-01

    Plant immunity against the majority of the microbial pathogens is conveyed by a phenomenon known as non-host resistance (NHR). This defence mechanism affords durable protection to plant species against given species of phytopathogens. We investigated the genetic basis of NHR in Arabidopsis against the wheat powdery mildew fungus Blumeria graminis f. sp. tritici (Bgt). Both primary and appressorial germ tubes were produced from individual Bgt conidia on the surface of the Arabidopsis leaves. Attempted infection occasionally resulted in successful penetration, which led to the development of an abnormal unilateral haustorium. Inoculation of a series of Arabidopsis defence-related mutants with Bgt resulted in the attenuation of reactive oxygen intermediate (ROI) production and salicylic acid (SA)-dependent defence gene expression in eds1, pad4 and nahG plants, which are known to be defective in some aspects of host resistance. Furthermore, Bgt often developed bilateral haustoria in the mutant Arabidopsis lines that closely resembled those formed in wheat. A similar decrease in NHR was observed following treatment of the wild-type Arabidopsis plants with cytochalasin E, an inhibitor of actin microfilament polymerisation. In eds1 mutants, inhibition of actin polymerisation severely compromised NHR in Arabidopsis against Bgt. This permitted completion of the Bgt infection cycle on these plants. Therefore, actin cytoskeletal function and EDS1 activity, in combination, are major contributors to NHR in Arabidopsis against wheat powdery mildew.

  3. Resistance of melon powdery mildew isolates to kresoxim-methyl in Guangxi and determination of its sensitivity to three fungicides%广西瓜类白粉病菌对醚菌酯的抗药性及其对3种药剂的敏感性检测

    Institute of Scientific and Technical Information of China (English)

    林珊宇; 朱桂宁; 颜梅新; 贤小勇

    2014-01-01

    [Objective]The resistance level, distribution and development of melon powdery mildew isolates to kresoxim-methyl in Guangxi were identified and effective alternative fungicides were screened to provide references for prevention and controlling of melon powdery mildew. [Method]From 2007 to 2012, bitter gourd, wax gourd, muskmelon, cucumber and bottle gourd disease samples were collected from Nanning, Guiping, and Beihai, etc. Their isolates’ resistance to kresoxim-methyl were detected by leaf disk tests. Sensitivity of high-resistant isolates to carbendazim, trifloxystrobin and propineb were also analyzed. [Result]The results showed that 83 melon powdery mildew population produced resistance to kresoxim-methyl in varying degrees. Resistant isolates were mainly distributed in bitter gourd powdery mildew and their resistant fre-quency was the highest (63.89%), while bottle gourd isolates had the lowest resistant frequency (6.67%). The resistant level of bitter gourd powdery mildew against to kresoxim-methyl increased gradually from 2007 to 2012 in Nanning City, resulting in development of high-resistance population. Fungicide screening assay results indicated that powdery mildew isolates with highly resistant to kresoxim-methyl, were highly drug-fast to carbendazim and cross-resistant to trifloxystrobin, but was sensi-tive to propineb. [Conclusion]In Guangxi, melon powdery mildew isolates were highly resistant to kresoxim-methyl and al-ternate use of propineb in the production process could be recommended.%【目的】了解广西瓜类白粉病菌对醚菌酯的抗性水平、抗性菌株的分布和发展趋势,并筛选瓜类白粉病防治药剂,为瓜类白粉病的抗性预防及防治提供参考。【方法】2007~2012年从广西南宁、桂平、北海等地采集苦瓜、冬瓜、甜瓜、黄瓜和葫芦瓜白粉病菌样品,采用叶碟保湿培养法检测供试菌株对醚菌酯的抗药性,并选取高抗菌株测定其对多菌灵、肟菌

  4. 打瓜白粉病药剂防治技术研究%Study on the Technique of Controling Seed- used Watermelon Powdery Mildew with Bactericides

    Institute of Scientific and Technical Information of China (English)

    韩盛; 李新辉; 于建新; 王艳; 杨渡; 李承业; 潘竟海; 李妍娥; 杨静飞; 严丽; 刘同业; 侯秀芳

    2012-01-01

    [ Objective ] Because seed - used watermelon powdery mildew induced serious damage in Xinjiang Region, we study the control efficacy of six bactericides to seed - used watermelon powdery mildew in the field. [Method] Comparison of the control efficacy of six bactericides to seed -used watermelon powdery mildew was made in the field plot experiment. [Result]Fourteen days after using these bactericides twice, thecontrol efficacy of 10% ZJ0712 wp 5 ,000 times solution is 73. 80% , achieving the highest control efficacy in all the six used bactericides And the control efficacy of 10% ZJ0712 wp 1,0000 times solution, 50% Kresoxim - methyl WG 3 ,000 times solution, 400 g/L Flusilazole EC 7 ,500 times solution and 25% Ethirimol wp 1,500 times solution are also effective, reaching the effect of 69. 69% , 69.56% , 68. 48% , and 67. 32% respectively after being used 14 days later. [ Conclusion]The control efficacy of ZJ0712 wp, 50% Kresoxim - methyl WG, 400 g/L Flusilazole EC and 25% Ethirimol wp are quite effective, so it is suggested that they could be used in production by turn, and the rule for controlling seed - used watermelon powdery mildew is made. The primary sources of infection and suitable time for controlling this disease have been clearly made, too. The key to controlling seed - used watermelon powdery mildew is to spray effective bactericide in time.%[目的]针对打瓜白粉病在新疆严重危害的现状,研究6种杀菌剂对打瓜白粉病的田间防治效果.[方法]采用田间小区试验,比较6种药剂的防效差异.[结果]两次施药后第14 d,10%苯醚菌酯悬浮剂5000倍液防效最高,防效达73.80%.10%苯醚菌酯悬浮剂10 000倍液、50%醚菌酯水分散粒剂3 000倍液、400 g/L氟硅唑乳油7 500倍液和25%乙嘧酚悬浮剂1 500倍液的防效也较好,药后14 d分别达69.69%、69.56%、68.48%和67.32%.[结论]4种药剂防效较好,推荐在生产中交替使用.提出了打瓜白粉病防治原则,明

  5. Capacidade combinatória em mamoeiro para resistência a oídio Combining ability for resistance to powdery-mildew in papaya

    Directory of Open Access Journals (Sweden)

    Marcelo Vivas

    2012-01-01

    Full Text Available A resistência genética constitui alternativa sustentável para o controle do oídio. Objetivando indicar possíveis combinações híbridas que contribuam para a redução da severidade de oídio em folha de mamoeiro, foi realizado um cruzamento dialélico envolvendo oito genótipos, sendo quatro do grupo 'Solo' e quatro do grupo 'Formosa'. Os 56 híbridos (F1's e recíprocos juntamente com seus genitores foram avaliados em blocos casualizados com quatro repetições. A severidade do oídio na folha foi quantificada em março e maio de 2010, respectivamente, aos 11 e 13 meses após o plantio. Com a média de cada tratamento foram estimadas as capacidades geral e específica de combinação. Assim, considerando as estimativas da capacidade combinatória obtidas com base na média das duas avaliações, as melhores combinações para os genitores avaliados quanto à severidade do oídio foram 'Maradol x Waimanalo', 'Maradol x Sunrise Solo 72/12', 'JS 12-4 x São Mateus', 'Sekati x Waimanalo', 'Sekati x Golden', 'Sekati x Sunrise Solo 72/12', 'Sekati x São Mateus', 'Waimanalo x São Mateus' e 'Golden x São Mateus'. Os resultados evidenciam ainda a possibilidade de obtenção de híbridos com potencial para redução da severidade do oídio provenientes de cruzamentos entre genótipos dos grupos 'Solo' e 'Formosa' e também em cruzamentos dentro do grupo 'Solo'.Genetic resistance represents a sustainable alternative to control powdery-mildew in papaya crop. Diallelic crosses were performed among eight papaya genotypes, belonging to 'Solo' and 'Formosa' heterotic groups, four from each one with aiming to indicate possible hybrid combinations that contribute to reducing the severity of powdery-mildew on leaf. The 56 hybrid combinations (F1's and reciprocals along with their parents were evaluated in a randomized complete block design with four replications. Powdery-mildew severity on leaves was measured in March and May 2010, respectively, at 11

  6. A barley SKP1-like protein controls abundance of the susceptibility factor RACB and influences the interaction of barley with the barley powdery mildew fungus.

    Science.gov (United States)

    Reiner, Tina; Hoefle, Caroline; Hückelhoven, Ralph

    2016-02-01

    In an increasing number of plant-microbe interactions, it has become evident that the abundance of immunity-related proteins is controlled by the ubiquitin-26S proteasome system. In the interaction of barley with the biotrophic barley powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh), the RAC/ROP [RAT SARCOMA-related C3 botulinum toxin substrate/RAT SARCOMA HOMOLOGUE (RHO) of plants] guanosine triphosphatase (GTPase) HvRACB supports the fungus in a compatible interaction. By contrast, barley HvRBK1, a ROP-binding receptor-like cytoplasmic kinase that interacts with and can be activated by constitutively activated HvRACB, limits fungal infection success. We have identified a barley type II S-phase kinase 1-associated (SKP1)-like protein (HvSKP1-like) as a molecular interactor of HvRBK1. SKP1 proteins are subunits of the SKP1-cullin 1-F-box (SCF)-E3 ubiquitin ligase complex that acts in the specific recognition and ubiquitination of protein substrates for subsequent proteasomal degradation. Transient induced gene silencing of either HvSKP1-like or HvRBK1 increased protein abundance of constitutively activated HvRACB in barley epidermal cells, whereas abundance of dominant negative RACB only weakly increased. In addition, silencing of HvSKP1-like enhanced the susceptibility of barley to haustorium establishment by Bgh. In summary, our results suggest that HvSKP1-like, together with HvRBK1, controls the abundance of HvRACB and, at the same time, modulates the outcome of the barley-Bgh interaction. A possible feedback mechanism from RAC/ROP-activated HvRBK1 on the susceptibility factor HvRACB is discussed.

  7. A functional EDS1 ortholog is differentially regulated in powdery mildew resistant and susceptible grapevines and complements an Arabidopsis eds1 mutant.

    Science.gov (United States)

    Gao, Fei; Shu, Xiaomei; Ali, Mohammad Babar; Howard, Susanne; Li, Nan; Winterhagen, Patrick; Qiu, Wenping; Gassmann, Walter

    2010-04-01

    Vitis vinifera (grapevine) is the most economically important deciduous fruit crop, but cultivated grapevine varieties lack adequate innate immunity to a range of devastating diseases. To identify genetic resources for grapevine innate immunity and understand pathogen defense pathways in a woody perennial plant, we focus in this study on orthologs of the central Arabidopsis thaliana defense regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). The family of EDS1-like genes is expanded in grapevine, and members of this family were previously found to be constitutively upregulated in the resistant variety 'Norton' of the North American grapevine species Vitis aestivalis, while they were induced by Erysiphe necator, the causal agent of grapevine powdery mildew (PM), in the susceptible V. vinifera variety 'Cabernet Sauvignon'. Here, we determine the responsiveness of individual EDS1-like genes in grapevine to PM and salicylic acid, and find that EDS1-like paralogs are differentially regulated in 'Cabernet Sauvignon', while two are constitutively upregulated in 'Norton'. Sequencing of VvEDS1 and VaEDS1 cDNA and genomic clones revealed high conservation in the protein-encoding sequence and some divergence of the promoter sequence in the two grapevine varieties. Complementation of the Arabidopsis eds1-1 mutant showed that the EDS1-like gene with highest predicted amino acid sequence similarity to AtEDS1 from either grapevine varieties is a functional ortholog of AtEDS1. Together, our analyses show that differential susceptibility to PM is correlated with differences in EDS1 expression, not differences in EDS1 function, between resistant 'Norton' and susceptible 'Cabernet Sauvignon'.

  8. Species and physiological race identification of melon powdery mildew fungus in Jiangsu,Zhejiang and Shanghai areas%江浙沪甜瓜白粉病菌及其生理小种的鉴定

    Institute of Scientific and Technical Information of China (English)

    李苹芳; 朱凌丽; 羊杏平; 徐锦华; 刘广; 姚协丰; 牛徐江

    2015-01-01

    为明确江浙沪地区甜瓜白粉病致病菌种类及优势生理小种,2014年秋季从江浙沪地区包括江苏宿迁宿城、淮安、南京六合、南京玄武、苏州吴中、南通海门,上海嘉定、奉贤,浙江宁波等地大棚甜瓜植株上采集了9份白粉病菌,通过镜检白粉孢子、考马斯亮蓝染色菌丝推断上述白粉病菌为单囊壳白粉菌Podosphaera xanthii;以南京玄武地区的白粉病菌DNA为模板扩增克隆其rDNA内转录间隔区(ITS)序列,分析确认其为单囊壳白粉菌Podosphaera xanthii;采用国际通用的13个鉴别寄主对上述白粉病菌进行喷雾接种鉴定,根据鉴别寄主抗感反应确认上述甜瓜白粉病菌为单囊壳白粉菌生理小种1,未发现其他生理小种。本研究初步明确了江浙沪地区甜瓜白粉病菌的菌种及优势生理小种,为甜瓜抗白粉病育种奠定了基础。%To identify the species and physiological races of melon powdery mildew fungus from Jiangsu,Zhejiang and Shanghai areas,nine powdery mildew fungus were collected from melon plants grown in plastic tunnels in southeast China in⁃lcuding Sucheng Suqian,Huai’an,Luhe Nanjing,Xuanwu Nanjing,Wuzhong Suzhou,Haimen Nantong in Jiangsu province, Jiading and Fengxian in Shanghai and Ningbo in Zhejiang province during autumn in 2014. Microscopic observation of the conidia and Coomassie brilliant blue staining of the hyphae identified them as Podosphaera xanthii. The rDNA internal tran⁃scribed space(ITS)sequence analysis of the fungus from Nanjing Xuanwu confirmed it as Podosphaera xanthii. When these pathogens were inoculated onto the 13 international standard differential host,they were classified as P. xanthii Race 1 ac⁃cording to their susceptible/resistant reactions,no other races were found. This study characterized the species and pre⁃dominate physiological races of melon powdery mildew fungus collected in Jiangsu,Zhejiang and Shanghai areas,which laid

  9. Powdery Mildew Resistance Conferred by Loss of the ENHANCED DISEASE RESISTANCE1 Protein Kinase Is Suppressed by a Missense Mutation in KEEP ON GOING, a Regulator of Abscisic Acid Signaling1[W][OA

    Science.gov (United States)

    Wawrzynska, Anna; Christiansen, Katy M.; Lan, Yinan; Rodibaugh, Natalie L.; Innes, Roger W.

    2008-01-01

    Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to infection by powdery mildew (Golovinomyces cichoracearum). EDR1 encodes a protein kinase, but its substrates and the pathways regulated by EDR1 are unknown. To identify components of the EDR1 signal transduction pathway(s), we conducted a forward genetic screen for mutations that suppressed edr1-mediated disease resistance. Genetic mapping and cloning of one of these suppressor mutations revealed a recessive missense mutation in the KEEP ON GOING gene (KEG; At5g13530), which we designated keg-4. KEG encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like repeats. The KEG protein has previously been shown to have ubiquitin ligase activity and to negatively regulate protein levels of the transcription factor ABCISIC ACID INSENSITIVE5. KEG mRNA levels were found to be 3-fold higher in edr1 mutant plants compared to wild type. Loss-of-function mutations in KEG are seedling lethal and are hypersensitive to glucose and abscisic acid (ABA). The keg-4 mutation, in contrast, conferred resistance to 6% glucose and suppressed edr1-mediated hypersensitivity to ABA, suggesting that the keg-4 mutation suppresses ABA signaling by altering KEG function. Several ABA-responsive genes were found to be further up-regulated in the edr1 mutant following ABA treatment, and this up-regulation was suppressed by the keg-4 mutation. We conclude that edr1-mediated resistance to powdery mildew is mediated, in part, by enhanced ABA signaling. PMID:18815384

  10. Powdery mildew resistance conferred by loss of the ENHANCED DISEASE RESISTANCE1 protein kinase is suppressed by a missense mutation in KEEP ON GOING, a regulator of abscisic acid signaling.

    Science.gov (United States)

    Wawrzynska, Anna; Christiansen, Katy M; Lan, Yinan; Rodibaugh, Natalie L; Innes, Roger W

    2008-11-01

    Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to infection by powdery mildew (Golovinomyces cichoracearum). EDR1 encodes a protein kinase, but its substrates and the pathways regulated by EDR1 are unknown. To identify components of the EDR1 signal transduction pathway(s), we conducted a forward genetic screen for mutations that suppressed edr1-mediated disease resistance. Genetic mapping and cloning of one of these suppressor mutations revealed a recessive missense mutation in the KEEP ON GOING gene (KEG; At5g13530), which we designated keg-4. KEG encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like repeats. The KEG protein has previously been shown to have ubiquitin ligase activity and to negatively regulate protein levels of the transcription factor ABCISIC ACID INSENSITIVE5. KEG mRNA levels were found to be 3-fold higher in edr1 mutant plants compared to wild type. Loss-of-function mutations in KEG are seedling lethal and are hypersensitive to glucose and abscisic acid (ABA). The keg-4 mutation, in contrast, conferred resistance to 6% glucose and suppressed edr1-mediated hypersensitivity to ABA, suggesting that the keg-4 mutation suppresses ABA signaling by altering KEG function. Several ABA-responsive genes were found to be further up-regulated in the edr1 mutant following ABA treatment, and this up-regulation was suppressed by the keg-4 mutation. We conclude that edr1-mediated resistance to powdery mildew is mediated, in part, by enhanced ABA signaling.

  11. Discovery of a Novel er1 Allele Conferring Powdery Mildew Resistance in Chinese Pea (Pisum sativum L. Landraces.

    Directory of Open Access Journals (Sweden)

    Suli Sun

    Full Text Available Pea powdery mildew, caused by Erysiphe pisi D.C., is an important disease worldwide. Deployment of resistant varieties is the main way to control this disease. This study aimed to screen Chinese pea (Pisum sativum L. landraces resistant to E. pisi, and to characterize the resistance gene(s at the er1 locus in the resistant landraces, and to develop functional marker(s specific to the novel er1 allele. The 322 landraces showed different resistance levels. Among them, 12 (3.73%, 4 (1.24% and 17 (5.28% landraces showed immunity, high resistance and resistance to E. pisi, respectively. The other landraces appeared susceptible or highly susceptible to E. pisi. Most of the immune and highly resistant landraces were collected from Yunnan province. To characterize the resistance gene at the er1 locus, cDNA sequences of PsMLO1 gene were determined in 12 immune and four highly resistant accessions. The cDNAs of PsMLO1 from the immune landrace G0005576 produced three distinct transcripts, characterized by a 129-bp deletion, and 155-bp and 220-bp insertions, which were consistent with those of er1-2 allele. The PsMLO1 cDNAs in the other 15 resistant landraces produced identical transcripts, which had a new point mutation (T→C at position 1121 of PsMLO1, indicating a novel er1 allele, designated as er1-6. This mutation caused a leucine to proline change in the amino acid sequence. Subsequently, the resistance allele er1-6 in landrace G0001778 was confirmed by resistance inheritance analysis and genetic mapping on the region of the er1 locus using populations derived from G0001778 × Bawan 6. Finally, a functional marker specific to er1-6, SNP1121, was developed using the high-resolution melting technique, which could be used in pea breeding via marker-assisted selection. The results described here provide valuable genetic information for Chinese pea landraces and a powerful tool for pea breeders.

  12. Discovery of a Novel er1 Allele Conferring Powdery Mildew Resistance in Chinese Pea (Pisum sativum L.) Landraces.

    Science.gov (United States)

    Sun, Suli; Fu, Haining; Wang, Zhongyi; Duan, Canxing; Zong, Xuxiao; Zhu, Zhendong

    2016-01-01

    Pea powdery mildew, caused by Erysiphe pisi D.C., is an important disease worldwide. Deployment of resistant varieties is the main way to control this disease. This study aimed to screen Chinese pea (Pisum sativum L.) landraces resistant to E. pisi, and to characterize the resistance gene(s) at the er1 locus in the resistant landraces, and to develop functional marker(s) specific to the novel er1 allele. The 322 landraces showed different resistance levels. Among them, 12 (3.73%), 4 (1.24%) and 17 (5.28%) landraces showed immunity, high resistance and resistance to E. pisi, respectively. The other landraces appeared susceptible or highly susceptible to E. pisi. Most of the immune and highly resistant landraces were collected from Yunnan province. To characterize the resistance gene at the er1 locus, cDNA sequences of PsMLO1 gene were determined in 12 immune and four highly resistant accessions. The cDNAs of PsMLO1 from the immune landrace G0005576 produced three distinct transcripts, characterized by a 129-bp deletion, and 155-bp and 220-bp insertions, which were consistent with those of er1-2 allele. The PsMLO1 cDNAs in the other 15 resistant landraces produced identical transcripts, which had a new point mutation (T→C) at position 1121 of PsMLO1, indicating a novel er1 allele, designated as er1-6. This mutation caused a leucine to proline change in the amino acid sequence. Subsequently, the resistance allele er1-6 in landrace G0001778 was confirmed by resistance inheritance analysis and genetic mapping on the region of the er1 locus using populations derived from G0001778 × Bawan 6. Finally, a functional marker specific to er1-6, SNP1121, was developed using the high-resolution melting technique, which could be used in pea breeding via marker-assisted selection. The results described here provide valuable genetic information for Chinese pea landraces and a powerful tool for pea breeders.

  13. Forecast Technology Research of Wheat Powdery Mildew Comprehensive Occurrence Degree in Henan Province%河南省小麦白粉病综合发生等级预测技术研究

    Institute of Scientific and Technical Information of China (English)

    李彤霄

    2015-01-01

    Based on the wheat powdery mildew investigation data and corresponding meteorological data from 1991 to 2010 in Zhenping county and Yichuan county, from 1991 to 2000 in Anyang county and Xiangcheng city,the meteorological factors affecting wheat powdery mildew occurrence degree were ana-lyzed,and Henan wheat powdery mildew regional and comprehensive forecasting models were built.The result showed that the wheat powdery mildew occurrence degrees of Zhenping, Yichuan, Anyang and Xiangcheng were all related to the relative humidity in March and the temperature and rainfall coefficient in late March last year,and the correlation coefficients of the four stations all passed significance test ofα=0.01.Henan wheat powdery mildew regional and comprehensive forecasting models were built using these two factors.Using the regional models to forecast the wheat powdery mildew occurrence degrees of the four stations in 2012,the forecasting degrees of three stations were the same as the real situation,and the other one had one degree of error,so the results were all in specified range.The comprehensive model was used to forecast the wheat powdery mildew occurrence degrees of Henan in 2011 and 2012,and the forecasting accuracy rate was 100%.The models can forecast the wheat powdery mildew occurrence de-gree in parts and all of Henan, and provide references for holding the wheat powdery mildew occurrence degree globally.%利用镇平县和伊川县1991—2010年、安阳县和项城市1991—2000年的小麦白粉病调查资料和气象观测资料,通过数理统计的方法分析影响小麦白粉病发生等级的各种气象因子,建立河南省小麦白粉病分区预测模型,并以此为基础建立河南省综合预测模型。研究表明,镇平、伊川、安阳和项城小麦白粉病发生等级均与3月份的相对湿度和上年3月下旬的温雨系数显著相关。利用以上2个气象因子建立了河南省小麦白粉病分区发生等级预测模

  14. Ontogenic resistance of leaves and fruit, and how leaf folding influences the distribution of powdery mildew on strawberry plants colonized by Podosphaera aphanis.

    Science.gov (United States)

    Asalf, Belachew; Gadoury, David M; Tronsmo, Anne Marte; Seem, Robert C; Dobson, Andrew; Peres, Natalia A; Stensvand, Arne

    2014-09-01

    Ontogenic or age-related resistance has been noted in many pathosystems but is less often quantified or expressed in a manner that allows the concept to be applied in disease management programs. Preliminary studies indicated that leaves and fruit of three strawberry cultivars rapidly acquired ontogenic resistance to the powdery mildew pathogen, Podosphaera aphanis. In the present study, we quantify the development of ontogenic resistance in controlled inoculations of 10 strawberry cultivars using diverse isolates of P. aphanis in New York and Florida, USA, and in Norway. We report the differential and organ-specific development of ontogenic resistance in the receptacle and externally borne strawberry achenes. We further report that rapid development of ontogenic resistance prior to unfolding of emergent leaves, rather than differential susceptibility of adaxial versus abaxial leaf surfaces, may explain the commonly observed predominance of powdery mildew on the lower leaf surfaces. Susceptibility of leaves and fruit declined exponentially with age. Receptacle tissue of berries inoculated at four phenological stages from bloom to ripe fruit became nearly immune to infection approximately 10 to 15 days after bloom, as fruit transitioned from the early green to the late green or early white stage of berry development, although the achenes remained susceptible for a longer period. Leaves also acquired ontogenic resistance early in their development, and they were highly resistant shortly after unfolding and before the upper surface was fully exposed. No significant difference was found in the susceptibility of the adaxial versus abaxial surfaces. The rapid acquisition of ontogenic resistance by leaves and fruit revealed a narrow window of susceptibility to which management programs might be advantageously adapted.

  15. 哈茨木霉菌防治安顺金刺梨白粉病试验初报%Preliminary Report on Test of Prevention and Control of Powdery Mildew of Anshun Var. Leioclada by Using Trichoderma Harzianum

    Institute of Scientific and Technical Information of China (English)

    程友忠; 韦景枫

    2015-01-01

    The trichoderma harzianum is a non-toxic and non-residue microbial fungicides. An experimental research of pre-vention and cure of powdery mildew of Anshun Rosa sterilis var. leioclada by using trichoderma harzianum was carried out. The results showed that the 2 250 g/hm2 trichoderma harzianum preparation had a good control effect on the powdery mildew of var. leioclada and could upgrade the yield of Rosa sterilis var. leioclada.%哈茨木霉菌是微生物杀菌剂,无毒无残留。通过哈茨木霉菌对安顺金刺梨白粉病防治试验研究,结果表明,2250 g/hm2哈茨木霉菌制剂对金刺梨白粉病有良好防治效果,并能提高金刺梨的产量。

  16. The Test Report about Kresoxim 50% WP Against Cucumber Powdery Mildew%50%醚菌酯可湿性粉剂防治黄瓜白粉病药效试验报告

    Institute of Scientific and Technical Information of China (English)

    李易初; 刘佳

    2012-01-01

    50%醚菌酯可湿性粉剂对黄瓜白粉病有较高的防效,试验中的防效为77.0%~88.6%,没有药害现象。使用时推荐剂量为50%醚菌酯可湿性粉剂247g/hm2,于黄瓜白粉病发病前或初开始喷药,间隔7天喷药2次以上。%50% Kresoxim WP on cucumber powdery mildew with high control effect,test the efficacy was 77.0%-88.6%,no injury phenomenon.Use the recommended dose is 50% Kresoxim WP 247g/hm2,cucumber powdery mildew in the beginning before the onset or spraying interval of 7 days of spraying 2 times.

  17. Melon Powdery Mildew Resistant Genes, Pathogen Differentiation Hosts and Breeding Germplasm%甜瓜白粉病的抗病基因、鉴定寄主及种质资源

    Institute of Scientific and Technical Information of China (English)

    林德佩

    2011-01-01

    This article reviews the research of melon Powdery Mildew resistant genes, pathogen differentiation hosts,germplasm for breeding resistance to Powdery Mildew. The characteristics of 13 melon lines used for PM pathogen differentiation are described.%综合了当前有关甜瓜白粉病抗病基因、病原菌种和生理小种及其载体种质资源的研究成果,同时介绍了抗白粉病种质资源在生理小种鉴定中的应用及13份甜瓜抗病种质的性状特征、特性.

  18. Study on Relationship of Sowing Time with Yield and Powdery Mildew%播种期对亚麻白粉病发病指数及产量的影响

    Institute of Scientific and Technical Information of China (English)

    陈娟; 乔红霞

    2012-01-01

    本试验验采用不同油用亚麻品种,分析研究了播种期对产量及白粉病发病情况的影响,结果表明播种期对白粉病发病的影响不显著,适当提早播种能较大幅度地提高油用亚麻产量,是一项行之有效的丰产栽培技术.%This paper analyzed the relationship of sowing time with the yield and the severity of powdery mildew, different oil flax varieties were investigated. The results showed that early sowing did not have an evident influence on powdery mildew but could increase the yield of flax significantly. Reasonable early sowing is an effective high - yield cultivation technique.

  19. Aegilops tauschii Accessions with Geographically Diverse Origin Show Differences in Chromosome Organization and Polymorphism of Molecular Markers Linked to Leaf Rust and Powdery Mildew Resistance Genes

    Science.gov (United States)

    Majka, Maciej; Kwiatek, Michał T.; Majka, Joanna; Wiśniewska, Halina

    2017-01-01

    Aegilops tauschii (2n = 2x = 14) is a diploid wild species which is reported as a donor of the D-genome of cultivated bread wheat. The main goal of this study was to examine the differences and similarities in chromosomes organization among accessions of Ae. tauschii with geographically diversed origin, which is believed as a potential source of genes, especially determining resistance to fungal diseases (i.e., leaf rust and powdery mildew) for breeding of cereals. We established and compared the fluorescence in situ hybridization patterns of 21 accessions of Ae. tauschii using various repetitive sequences mainly from the BAC library of wheat cultivar Chinese Spring. Results obtained for Ae. tauschii chromosomes revealed many similarities between analyzed accessions, however, some hybridization patterns were specific for accessions, which become from cognate regions of the World. The most noticeable differences were observed for accessions from China which were characterized by presence of distinct signals of pTa-535 in the interstitial region of chromosome 3D, less intensity of pTa-86 signals in chromosome 2D, as well as lack of additional signals of pTa-86 in chromosomes 1D, 5D, or 6D. Ae. tauschii of Chinese origin appeared homogeneous and separate from landraces that originated in western Asia. Ae. tauschii chromosomes showed similar hybridization patterns to wheat D-genome chromosomes, but some differences were also observed among both species. What is more, we identified reciprocal translocation between short arm of chromosome 1D and long arm of chromosome 7D in accession with Iranian origin. High polymorphism between analyzed accessions and extensive allelic variation were revealed using molecular markers associated with resistance genes. Majority of the markers localized in chromosomes 1D and 2D showed the diversity of banding patterns between accessions. Obtained results imply, that there is a moderate or high level of polymorphism in the genome of Ae

  20. 压砂甜瓜白粉病病原菌18S rDNA序列分析%Analysis of 18S rDNA Sequence of Melon Powdery Mildew from Lands Overlaid with Sands in Ningxia

    Institute of Scientific and Technical Information of China (English)

    杨静玲; 刘建利

    2011-01-01

    [Objective] The aim was to analyze the 18S rDNA sequence of melon powdery mildew from lands overlaid with sands. [Method] Thepathogen of melon powdery mildew was isolated from infected plants of "Yujinxiang" ,a major melon variety eultivated in lands overlaid with sandsof droughty midregion in Ningxia. Genome DNA was extracted from its conidia using Chelex-100 method. 18S rDNA sequence was amplified byPCR,which was analyzed by Blast after sequencing,and the phylogenetic tree was constructed. [ Result] 18S rDNA sequence analysis showed thatthe pathogen of melon powdery mildew belonged to Podosphaera. [Conclusion] The study provided reference for biocontrol and disease-resistancebreeding against melon powdery mildew.%[目的] 测定并分析压砂甜瓜白粉病痛原菌的18S rDNA序列.[方法] 从宁夏中部干旱带压砂甜瓜主栽品种“玉金香”发病植株上分离白粉病病原菌,采用Chelex-100法从其分生孢子中提取基因组DNA,PCR扩增18S rDNA序列,测序后进行Blast分析比对,并构建系统发育树.[结果] 18S rDNA序列分析表明压砂甜瓜白粉病痛原菌属单囊壳属(Podosphaera).[结论] 为生物防治压砂甜瓜白粉病和抗白粉病育种研究提供了参考.

  1. Study on Occurrence Law and Control of Powdery Mildew of Mahonia fortunei%狭叶十大功劳白粉病的发病规律及防治研究

    Institute of Scientific and Technical Information of China (English)

    耿晓东; 周英; 陈君君

    2013-01-01

      为了防治狭叶十大功劳白粉病,在充分了解其发病规律的基础上,对狭叶十大功劳白粉病的发病情况进行了较系统的观察和调查,同时应用4种药剂对狭叶十大功劳白粉病进行了药剂防治试验。结果表明:狭叶十大功劳白粉病在苏州全年发病具有明显的季节性,每年的5月上旬至6月中旬和10月下旬至11月下旬是2个发病高峰期。在发病初期使用15%三唑酮可湿性粉剂2000倍液进行药剂处理,可以有效控制病情的蔓延。%  In order to control the powdery mildew of Mahonia fortunei ,based on its occurrence law ,the inci-dences of powdery mildew of Mahonia f ortunei were observed and investigated systematically ,and chemical control experiment on powdery mildew of Mahonia f ortunei were tested by 4 kinds of chemicals .The results showed that the powdery mildew of Mahonia f ortunei had obvious seasonal character in Suzhou .It occurred in early May to mid June and late October to late November as two peak period of disease .Using 15% triadimefon WP 2 000 times liquid could effectively control the disease at the early stage .

  2. Research on the Resistance Induced with Multi-factors Combination of Pepper to Powdery Mildew%多因子联合诱导辣椒对白粉病的抗病性研究

    Institute of Scientific and Technical Information of China (English)

    赵建方; 陈洪美; 徐臣善; 李东臣; 张乃琴; 金桂芳

    2013-01-01

    In order to study the new method to control powdery mildew of peppers effectively ,the different in-ductive resistance factors were selected to combin into new inductive combinations ,resistance of pepers to pow-dery mildew was determined .The results showed that the inductive effect of inductive combinations on powdery mildew of peppers was better than single factor .Both successive and repeated induction of different combina-tions further improved the inductive effect ,the control rate of powdery mildew was over 80% in field ,and the effect of combined induction was higher than conventional fungicide .%为了探索有效防治辣椒白粉病的新方法,将筛选得到的多个不同的抗病诱导因子进行配伍,组合成新的诱导组合体,研究其诱导辣椒苗对白粉病的抗病性影响。结果表明:诱导组合体的诱导效应比单一因子高;用不同的诱导组合体进行相继诱导和循环诱导,进一步提高了诱导效应,对辣椒白粉病的田间防治效果达到80%以上,高于常规杀菌剂的防治效果。

  3. 部分蔷薇属种质资源的白粉病抗性评价%Assessing the Resistance of Several Rosa Germplasms to Powdery Mildew (Podosphaera pannosa)

    Institute of Scientific and Technical Information of China (English)

    王蕴红; 王金耀; 张启翔; 罗乐; 于超; 潘会堂

    2013-01-01

    The resistance to the powdery mildew of ten wild Rosa materials and four rose cultivars were assessed. The No. 2 material of Rosa beggeriana, R. oxyacantha, the No. 3 material of R. laxa and ' Kardinal' were high resistance germ-plasms. ' Sun City' , R. iliensis and the No. 1 material of R. beggeriana were high sensitive germplasms. The process of powdery mildew pathogen infection was observed under microscope. The results showed that after inoculation the mycelium and spores of powdery mildew were successfully attached on the leave surface and the mycelium increased with the days after inoculation. The infection procedure completed in 96 h-120 h after inoculation. The development of the powdery mildew on Rosa leaves were described with latent period, disease score and rate of symptom development.%对5种10份新疆野生蔷薇种质资源和4个月季品种进行了白粉病抗性评价,结果发现了弯刺蔷薇2号、尖刺蔷薇、疏花蔷薇3号和‘红衣主教’4个高抗材料,‘太阳城’、伊犁蔷薇和弯刺蔷薇1号3个易感材料,表明野生蔷薇属资源中存在较为优良的抗白粉病种质;显微观察了月季白粉病病原菌侵染叶片的过程,发现白粉病侵染月季的过程经过96 ~ 120 h即可完成,并从白粉病的潜伏时间、病情级别、病级的发展速率3个方面描述了发病过程.

  4. 小麦抗白粉病分子育种的研究现状及研究进展%Research Status and Advances on Molecular Breeding about Resistance to Powdery Mildew in Wheat

    Institute of Scientific and Technical Information of China (English)

    刘国圣

    2016-01-01

    Wheat powdery mildew is the main process of wheat diseases, therefore the disease resistant variety is the most effective and economical measure in the prevention and cure of the disease. In recent years, molecular marker technology research and development has become the basis of resistance to powdery mildew in science and technology, this technology provides great convenience for white powder resistance molecular breeding. Based on this, from the status in molecular breeding of resistance to powdery mildew, this paper analyzed the three types of wheat resistance and wheat powdery mildew resistance gene cloning, and then studied on development from gene angle positioning.%小麦白粉病成为小麦种植过程中主要病害之一,在防治该病时采用抗病品种是最为有效、经济的措施。近年来,分子标记技术的研究与发展成为了抗白粉病技术中比较科学的技术,这种技术为抗白粉分子育种提供极大的便利。基于此,从抗白粉病的分子育种研究现状出发,分析小麦抗性的三种类型及小麦抗白粉病的基因克隆,然后从基因定位角度探讨研究发展。

  5. Study on Indicators Related with Pea Powdery Mildew Resistance%豌豆白粉病抗性相关指标的研究

    Institute of Scientific and Technical Information of China (English)

    张丽娟; 杨晓明; 陆建英; 王昶

    2015-01-01

    It is studied the relations between pea powdery mildew resistance and physiological indicators. Selected 4 kinds of pea with different resistance to pea powdery mildew. The content of soluble sugar and chloroplast changes in activity of specific enzymes such as SOD,CAT,POD,PPO and PAL are detected. The result shows that the content of chloroplast and the activity of POD,PPO and PAL are decreased as the resistance weakened,the activity of CAT was increased as the resistance weakened,while there is no significant correlation in content of the activity of SOD.The result of variance analysis illustrated the significant difference in the content of chloroplast and the activity of PPO,PAL and CAT between different cultivars (P<0.01). So it is confirmed that the content of chloroplast and the activity of PAL and CAT could used as indicator for resistance to pea powdery mildow.%为研究豌豆白粉病抗病性与各生理指标间的关系,选取4种抗性不同的豌豆品种为试材,测定各品种间叶绿素和可溶性糖含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性变化。结果表明,不同抗性品种中叶绿素含量、POD、PPO活性和PAL活性随豌豆白粉病抗性减弱而降低;CAT活性随豌豆白粉病抗性减弱而升高;SOD活性与豌豆白粉病抗性没有明显变化规律。方差分析结果显示,不同抗感病品种间叶绿素含量、PPO活性、PAL活性和CAT活性差异极显著(P<0.01),因此可以用叶绿素含量、PPO活性、PAL活性和CAT活性来反映对豌豆白粉病抗性的强弱。

  6. Mechanisms of Resistance to an Azole Fungicide in the Grapevine Powdery Mildew Fungus, Erysiphe necator.

    Science.gov (United States)

    Frenkel, Omer; Cadle-Davidson, Lance; Wilcox, Wayne F; Milgroom, Michael G

    2015-03-01

    We studied the mechanisms of azole resistance in Erysiphe necator by quantifying the sensitivity to myclobutanil (EC50) in 65 isolates from the eastern United States and 12 from Chile. From each isolate, we sequenced the gene for sterol 14α-demethylase (CYP51), and measured the expression of CYP51 and homologs of four putative efflux transporter genes, which we identified in the E. necator transcriptome. Sequence variation in CYP51 was relatively low, with sequences of 40 U.S. isolates identical to the reference sequence. Nine U.S. isolates and five from Chile carried a previously identified A to T nucleotide substitution in position 495 (A495T), which results in an amino acid substitution in codon 136 (Y136F) and correlates with high levels of azole resistance. We also found a nucleotide substitution in position 1119 (A1119C) in 15 U.S. isolates, whose mean EC50 value was equivalent to that for the Y136F isolates. Isolates carrying mutation A1119C had significantly greater CYP51 expression, even though A1119C does not affect the CYP51 amino acid sequence. Regression analysis showed no significant effects of the expression of efflux transporter genes on EC50. Both the Y136F mutation in CYP51 and increased CYP51 expression appear responsible for azole resistance in eastern U.S. populations of E. necator.

  7. 新疆伊犁地区胡麻白粉病发生与消长规律研究%Occurrence, Growth and Decline of Flax Powdery Mildew (Oidium Lini Skoric) in Yili

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    The occurrence , growth and decline of flax powdery mildew ( Oidium Lini Skoric) were investigated during 2010-2012 in Yili, Xinjiang, the results showed that the first time of occurrence of flax powdery mildew was the late of June , and the peak time was the middle of July , the disease spread speedily and shortly.The occurrence and epidemic of flax powdery mildew had a close relationship with the local meteorological factors.%  2010-2012年在新疆伊宁市对胡麻白粉病田间发生时期、发生与消长规律进行了系统研究,结果表明:新疆伊宁市胡麻白粉病始发期为6月下旬,盛发期为7月中旬,胡麻白粉病呈现发病时间短,流行速度快的特点。胡麻白粉病发生流行跟当地的气象因素有密切的关系。

  8. Control Effect of Endophytic Bacterium LP 5 to Cucumber Powdery Mildew%植物内生细菌LP5对黄瓜白粉病的田间防治效果

    Institute of Scientific and Technical Information of China (English)

    郭小英; 刘慧平; 韩巨才

    2011-01-01

    以翠贝为对照药剂,比较了植物内生细菌LP5发酵液对黄瓜白粉病的田间防治效果.结果表明,对照药剂翠贝对黄瓜白粉病的防治效果达88.3%,内生细菌LP5的发酵液对黄瓜白粉病的防治效果这79.4%,显然内生细菌LP5具有较好的防治效果,具有一定的开发应用价值.%Using beth as the contrast agent, the field control effect of fermentation liquor from endophytic bacterium LP5 on cucumber powdery mildew was tested. The control effect of beth on cucumber powdery mildew was 88.3%, the effect of fermentation liquor of LP5 was 79.3%. The result showed that endophytic bacterum LP5 had obvious control effect on cucumber powdery mildew, so it had certain development and application value.

  9. Ectopic Expression of the Wild Grape WRKY Transcription Factor VqWRKY52 in Arabidopsis thaliana Enhances Resistance to the Biotrophic Pathogen Powdery Mildew But Not to the Necrotrophic Pathogen Botrytis cinerea.

    Science.gov (United States)

    Wang, Xianhang; Guo, Rongrong; Tu, Mingxing; Wang, Dejun; Guo, Chunlei; Wan, Ran; Li, Zhi; Wang, Xiping

    2017-01-01

    WRKY transcription factors are known to play important roles in plant responses to biotic stresses. We previously showed that the expression of the WRKY gene, VqWRKY52, from Chinese wild Vitis quinquangularis was strongly induced 24 h post inoculation with powdery mildew. In this study, we analyzed the expression levels of VqWRKY52 following treatment with the defense related hormones salicylic acid (SA) and methyl jasmonate, revealing that VqWRKY52 was strongly induced by SA but not JA. We characterized the VqWRKY52 gene, which encodes a WRKY III gene family member, and found that ectopic expression in Arabidopsis thaliana enhanced resistance to powdery mildew and Pseudomonas syringae pv. tomato DC3000, but increased susceptibility to Botrytis cinerea, compared with wild type (WT) plants. The transgenic A. thaliana lines displayed strong cell death induced by the biotrophic powdery mildew pathogen, the hemibiotrophic P. syringe pathogen and the necrotrophic pathogen B. cinerea. In addition, the relative expression levels of various defense-related genes were compared between the transgenic A. thaliana lines and WT plants following the infection by different pathogens. Collectively, the results indicated that VqWRKY52 plays essential roles in the SA dependent signal transduction pathway and that it can enhance the hypersensitive response cell death triggered by microbial pathogens.

  10. Occurrence Grade Index Model of Dynamic Early Warning for Wheat Powdery Mildew in Typical Region%典型区域小麦白粉病发生气象等级动态预警模型

    Institute of Scientific and Technical Information of China (English)

    张蕾; 霍治国; 姜燕; 王丽

    2015-01-01

    通过分析历年小麦白粉病病情指数随时间的变化特点,将河南省南阳市的病情资料统一内插处理为以周为时间尺度的资料序列,将河北省正定县、辛集市、馆陶县和磁县的资料统一内插处理为以候为时间尺度的资料序列。利用2001-2010年小麦白粉病观测资料及相应时段的气象资料,采用秩相关分析和通径分析方法筛选分析影响白粉病发生等级的关键因子及因子贡献,基于Bayes准则建立南阳市和河北4县的区域小麦白粉病等级预测模型。结果表明:小麦白粉病病情指数随时间的变化符合Logistic曲线特点,内插处理效果较好;影响南阳市小麦白粉病发生的关键因子是前1周的病害发生等级、前1周至当周的相对湿度、前2周至当周的日照时数和前3周至当周的降雨系数,影响河北4县的关键因子是前1候的病害发生等级、前3候至当候的平均温度、前3候至当候的降水量和前3候至当候的降雨系数。利用指标模型对南阳市和河北4县病害发生等级进行检验,达到完全“一致”的准确率超过85%,“基本一致”的准确率超过90%,说明模型预警效果较好,可以用于相应区域小麦白粉病短时临近预报。%As being prone to wheat powdery mildew, Henan and Hebei province are affected severely by wheat powdery mildew. Through analysis on variable characteristic of disease index for winter powdery mildew, the disease index data in Nanyang city was interpolated at week scale and interpolated at pentad scale in Zhengding, Xinji, Guantao and Cixian. Based on disease observation data for wheat powdery mildew from 2001 to 2010 and daily meteorological data for corresponding period, the key factors and key period affecting occurrence grade for wheat powdery mildew were selected using rank correlation analysis and path analysis. Occurrence grade index model of dynamic warning for wheat powdery mildew

  11. 优质抗白粉病网纹甜瓜新品系的选育及利用%Breeding and Using of New Muskmelon Strains Which is Good in Quality and Powdery Mildew Resistant

    Institute of Scientific and Technical Information of China (English)

    李秀秀; 段爱民; 吕敬刚; 李长缨; 焦定量; 张艳宁; 加藤正弘

    2001-01-01

    Powdery mildew resistant Hami melon type variety was used tocross with muskmelon variety,then through inbreeding successively,seperating and selecting,according to the results of powdery mildew development naturally in field and artificial inoculation in seedling stage,three muskmelon strains which is powdery mildew resistant were obtained.The characteristics of their fruits were surveyed and the hybrid combinations by them were made.Three strains all show good netted veins,sick pulp and high sugar content.This will supply parent materials for breeding of new muskmelon hybrid.%利用抗病的哈密瓜类型材料与网纹类型材料杂交,结合田间自然发病和苗期人工接种抗性鉴定,通过连续自交分离选择,获得3个稳定的抗白粉病的网纹类型品系材料。经果实性状调查和杂交组合配制,3个品系均表现出网纹形成良好、果肉厚,折光糖含量高等特点,为网纹甜瓜新品种选育提供了亲本材料。

  12. Comparative genetic mapping revealed powdery mildew resistance gene MlWE4 derived from wild emmer is located in same genomic region of Pm36 and Ml3D232 on chromosome 5BL

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong; WANG Yong; CHEN Yong-xing; LIU Zhi-yong; OUYANG Shu-hong; WANG Li-li; CUI Yu; WU Qiu-hong; LIANG Yong; WANG Zhen-zhong; XIE Jing-zhong; ZHANG De-yun

    2015-01-01

    Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most devastating wheat diseases. Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is a promising source of disease resistance for wheat. A powdery mildew resistance gene conferring resistance to B. graminis f. sp. tritici isolate E09, originating from wild emmer wheat, has been transferred into the hexaploid wheat line WE4 through crossing and backcrossing. Genetic analyses indicated that the powdery mildew resistance was control ed by a single dominant gene, temporarily designated MlWE4. By mean of comparative genomics and bulked segregant analysis, a genetic linkage map of MlWE4 was constructed, and MlWE4 was mapped on the distal region of chromosome arm 5BL. Comparative genetic linkage maps showed that genes MlWE4, Pm36 and Ml3D232 were co-segregated with markers XBD37670 and XBD37680, indicating they are likely the same gene or al eles in the same locus. The co-segregated markers provide a starting point for chromosome landing and map-based cloning of MlWE4, Pm36 and Ml3D232.

  13. 枯草芽孢杆菌防治草莓白粉病的田间试验%Field Efficacy Trials of Bacillus subtilis against Powdery Mildew of Strawberry

    Institute of Scientific and Technical Information of China (English)

    彭燕; 冯清拔; 伍书钦

    2016-01-01

    Strawberry powdery mildew is a major disease in qionghai strawberry production , seriously affecting the production of strawberry. Qionghai strawberry planting during the low temperature, high humidity climate, is advantageous to the strawberry powdery mildew. In this article, through different combination formula discovery: Bacillus subtilis according to 4050 g/hm2 dosage used alone to prevent strawberry powdery mildew control effect was 92.09%, and the incidence of mixed chemicals-luna, do after treatment with, has a fast control effect and the advantages of long effective period.%草莓白粉病是琼海草莓生产中的常发性主要病害,严重影响草莓的生产.琼海草莓种植期间低温、 高湿气候情况频发,有利于草莓白粉病的发生.通过不同配方组合发现:枯草芽孢杆菌按4050 g/hm2用量单独使用,预防草莓白粉病防效达92.09%,发病后混合化学药剂露娜森做治疗,具有防效快、 持效期长等优点.

  14. The antagonistic strain Bacillus subtilis UMAF6639 also confers protection to melon plants against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses.

    Science.gov (United States)

    García-Gutiérrez, Laura; Zeriouh, Houda; Romero, Diego; Cubero, Jaime; de Vicente, Antonio; Pérez-García, Alejandro

    2013-05-01

    Biological control of plant diseases has gained acceptance in recent years. Bacillus subtilis UMAF6639 is an antagonistic strain specifically selected for the efficient control of the cucurbit powdery mildew fungus Podosphaera fusca, which is a major threat to cucurbits worldwide. The antagonistic activity relies on the production of the antifungal compounds iturin and fengycin. In a previous study, we found that UMAF6639 was able to induce systemic resistance (ISR) in melon and provide additional protection against powdery mildew. In the present work, we further investigated in detail this second mechanism of biocontrol by UMAF6639. First, we examined the signalling pathways elicited by UMAF6639 in melon plants, as well as the defence mechanisms activated in response to P. fusca. Second, we analysed the role of the lipopeptides produced by UMAF6639 as potential determinants for ISR activation. Our results demonstrated that UMAF6639 confers protection against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses, which include the production of reactive oxygen species and cell wall reinforcement. We also showed that surfactin lipopeptide is a major determinant for stimulation of the immune response. These results reinforce the biotechnological potential of UMAF6639 as a biological control agent.

  15. Efficacy Trial of Ethirimol and Other Fungicides against Powdery Mildew of Pumpkin%乙嘧酚等药剂防治南瓜白粉病药效试验

    Institute of Scientific and Technical Information of China (English)

    张焕春; 徐桂凤; 尹国香; 刘学卿; 夏秀波; 曹守军

    2012-01-01

      In order to solve the problem of Oidium sp. showing resistance against triazole fungicides, we carried out the trail to screen out effective fungicides against the powdery mildew of pumpkin in greenhouse. The results showed that ethirimol, kumulus and hexaconazole had better control effects against the powdery mildew of pumpkin, and ethirimol possessed the highest control efficiency of 92.82%, so it was the best fungicide using together with other fungicides to control powdery mildew of pumpkin.%  针对南瓜白粉病菌对三唑类农药产生抗药性的问题,进行了几种新药剂防治大棚南瓜白粉病的防效筛选试验.试验结果表明,乙嘧酚、硫磺、己唑醇对南瓜白粉病有较好的防治效果,其中乙嘧酚防效最高,达到92.82%,可作为首选药剂,与其他农药配合使用.

  16. Ectopic Expression of the Wild Grape WRKY Transcription Factor VqWRKY52 in Arabidopsis thaliana Enhances Resistance to the Biotrophic Pathogen Powdery Mildew But Not to the Necrotrophic Pathogen Botrytis cinerea

    Science.gov (United States)

    Wang, Xianhang; Guo, Rongrong; Tu, Mingxing; Wang, Dejun; Guo, Chunlei; Wan, Ran; Li, Zhi; Wang, Xiping

    2017-01-01

    WRKY transcription factors are known to play important roles in plant responses to biotic stresses. We previously showed that the expression of the WRKY gene, VqWRKY52, from Chinese wild Vitis quinquangularis was strongly induced 24 h post inoculation with powdery mildew. In this study, we analyzed the expression levels of VqWRKY52 following treatment with the defense related hormones salicylic acid (SA) and methyl jasmonate, revealing that VqWRKY52 was strongly induced by SA but not JA. We characterized the VqWRKY52 gene, which encodes a WRKY III gene family member, and found that ectopic expression in Arabidopsis thaliana enhanced resistance to powdery mildew and Pseudomonas syringae pv. tomato DC3000, but increased susceptibility to Botrytis cinerea, compared with wild type (WT) plants. The transgenic A. thaliana lines displayed strong cell death induced by the biotrophic powdery mildew pathogen, the hemibiotrophic P. syringe pathogen and the necrotrophic pathogen B. cinerea. In addition, the relative expression levels of various defense-related genes were compared between the transgenic A. thaliana lines and WT plants following the infection by different pathogens. Collectively, the results indicated that VqWRKY52 plays essential roles in the SA dependent signal transduction pathway and that it can enhance the hypersensitive response cell death triggered by microbial pathogens. PMID:28197166

  17. Adaptabilidade e estabilidade de genótipos de soja avaliados para resistência ao oídio Adaptability and stability of soybean genotypes evaluated for resistance to powdery mildew

    Directory of Open Access Journals (Sweden)

    Derval Gomes Pereira

    2008-10-01

    Full Text Available O objetivo desta pesquisa foi identificar genótipos de soja com adaptabilidade e estabilidade de comportamento para resistência ao oídio em condições de campo. O trabalho foi realizado no Campo Experimental Professor Diogo Alves de Mello, do Departamento de Fitotecnia, da Universidade Federal de Viçosa (UFV, em Viçosa, Minas Gerais. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições, disposto em parcelas subdivididas, com 15 genótipos (parcelas e sete épocas de avaliação (subparcela. A avaliação da incidência e severidade do oídio nos genótipos foi realizada por meio da quantificação visual do nível de infecção (NI provocado pelo oídio, sendo avaliados o nível de infecção da área foliar infectada pelo oídio (NIAFI e o nível de infecção do folíolo mais infectado pelo oídio (NIFI. Foram realizadas a análise de variância e análise de adaptabilidade e estabilidade conforme EBERHART & RUSSELL (1966. Os resultados permitiram tirar as seguintes conclusões: os genótipos que apresentaram os melhores níveis de resistência, em geral, também foram os de melhor adaptabilidade e estabilidade, tanto para NIAFI quanto para NIFI, com destaque para: UFV 89-361826 T2, UFV 94-334268, UFV-16 e UFV-19, FT-10 RC5 (F3, FT-Abyara RC6 (F2, Doko RC, FT-Abyara RC5 (F4, enquanto que os mais suscetíveis foram os de pior previsibilidade (estabilidade de comportamento, com destaque para UFV 94-5126, FT-104, UFV 94-3500, FT-Cristalina, FT-Estrela e BR-16.The objective of this research was to identify soybean genotypes with good adaptability and stability of behavior for resistance to powdery mildew in field conditions. The work was carried out at the Professor Diogo Alves de Mello Experimental Station, Agronomy Department of the Federal University of Viçosa (UFV, Viçosa, Minas Gerais. The experiment was arranged in a randomized block design, in split-plots, with 15 genotypes (plots and seven

  18. The Morphology of Six Powdery Mildew Account and rDNA ITS Phylogenetic Analysis in QingHai Province%青海省6种白粉菌的形态记述及rDNA-ITS 系统发育分析

    Institute of Scientific and Technical Information of China (English)

    樊桂芳

    2015-01-01

    In this paper, we classified and identified six kinds of powdery mildew in Qinghai on morphological, and carried on rDNA- ITS amplification and sequencing experiments. Phylogenetic tree was constructed. We analyzed the several species phylogenetic relationship between each other. Studies showed that the results of morphological are consistent with subsystem development, and have confirmed the international theories and methods of classifition of powdery mildew are reasonable.%对采自青海省的6种白粉菌进行了形态学分类鉴定,并对这几种 rDNA-ITS 序列进行扩增和测序,构建了系统发育树,分析了这几种白粉病菌的种类和彼此之间的系统发育关系。研究证明,形态分类学结果与分子系统发育结果一致,也证实国际白粉菌分类理论与方法的合理性。

  19. 醚菌酯可湿性粉剂对黄瓜白粉病的防效研究%Study on Control Effect of Kersoxim-Methyl WP on Cucumber Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Powdery mildew is a main leaf-disease in cucumbercultivation which serious damage to the produc-tion .Fungicide application is an effective measure in controlling the disease at present .In order to determine the control effects and optimal dosage of Kersoxim-Methyl WP on cucumber powdery mildew ,its control effects were tested in 2010~2011 .The results showed that the control efficiency of Kersoxim-Methyl WP on cucum-ber powdery mildew was 66 .7% ~88 .6% ,with no phytotoxicity to cucumber ,which indicated Kersoxim-Meth-yl could be applied to control of cucumber powdery midew .%  黄瓜白粉病是黄瓜栽培过程中普遍发生的叶部病害,严重危害黄瓜生产,药剂防治是目前防治该病害的主要手段。为了测定醚菌酯可湿性粉剂对黄瓜白粉病的防治效果及最佳使用剂量,2010和2011年连续2 a进行了醚菌酯可湿性粉剂对黄瓜白粉病的药效试验。结果表明:该药剂对黄瓜白粉病的防效达66.7%~88.6%,对黄瓜生产安全无药害,可以用于对黄瓜白粉病的防治。

  20. Produtos alternativos no controle do oídio em mudas de eucalipto Alternative products to control powdery mildew on eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Rafaela Mazur Bizi

    2008-06-01

    Full Text Available A silvicultura brasileira tem empregado o eucalipto pela sua adaptabilidade, rápido crescimento e produtividade, além de possuir outras características como a qualidade, diversidade e adequação de sua madeira para a indústria. Para tal, existe a necessidade de uma produção contínua de mudas, as quais podem ser atacadas pelo fungo Oidium sp. O controle do oídio é feito com fungicidas, mesmo não havendo produtos registrados para o eucalipto. O objetivo deste trabalho foi avaliar produtos alternativos (sais e tanino, óleos, extratos de plantas, leite e derivados, e antagonistas para o controle desta doença comparando os mais promissores com fungicida. Os produtos foram pulverizados em mudas de Eucalyptus benthamii Maiden & Cambage e mantidas em casa-de-vegetação com alto potencial de inóculo de Oidium sp. A severidade da doença foi avaliada por meio de uma escala de notas de 0 (ausência de sintomas a 4 (sintomas muito severo e calculada a área abaixo da curva de progresso da doença (AACPD. Verificou-se que, os menores valores de AACPD de oídio foram obtidos com piraclostrobina + epoxiconazol, que controlou 92 % da doença, e os melhores produtos alternativos testados foram o leite de vaca e Lecanicillium sp. que controlaram respectivamente 36,5 % e 33,9 % da doença no ensaio comparativo.Eucalypt plays an important role in Brazilian forestry because of its good adaptation, fast growth, high productivity, as well as a lot of good qualities for industry. Eucalyptus reforestation needs a continuous production of seedlings, which can be attacked by Oidium sp. The control of powdery mildew is based on fungicides, but for eucalypts there are no products commercially registered. The objective of this work was to evaluate chemical products, essential oils, plants extracts, milk and dairy products and antagonist for the alternative control of this disease. Seedlings of E. benthamii Maiden & Cambage were used in the assays. Disease

  1. The powdery mildew resistance gene REN1 co-segregates with an NBS-LRR gene cluster in two Central Asian grapevines

    Directory of Open Access Journals (Sweden)

    Morgante Michele

    2009-12-01

    Full Text Available Abstract Background Grape powdery mildew is caused by the North American native pathogen Erysiphe necator. Eurasian Vitis vinifera varieties were all believed to be susceptible. REN1 is the first resistance gene naturally found in cultivated plants of Vitis vinifera. Results REN1 is present in 'Kishmish vatkana' and 'Dzhandzhal kara', two grapevines documented in Central Asia since the 1920's. These cultivars have a second-degree relationship (half sibs, grandparent-grandchild, or avuncular, and share by descent the chromosome on which the resistance allele REN1 is located. The REN1 interval was restricted to 1.4 cM using 38 SSR markers distributed across the locus and the segregation of the resistance phenotype in two progenies of collectively 461 offspring, derived from either resistant parent. The boundary markers delimit a 1.4-Mbp sequence in the PN40024 reference genome, which contains 27 genes with known functions, 2 full-length coiled-coil NBS-LRR genes, and 9 NBS-LRR pseudogenes. In the REN1 locus of PN40024, NBS genes have proliferated through a mixture of segmental duplications, tandem gene duplications, and intragenic recombination between paralogues, indicating that the REN1 locus has been inherently prone to producing genetic variation. Three SSR markers co-segregate with REN1, the outer ones confining the 908-kb array of NBS-LRR genes. Kinship and clustering analyses based on genetic distances with susceptible cultivars representative of Central Asian Vitis vinifera indicated that 'Kishmish vatkana' and 'Dzhandzhal kara' fit well into local germplasm. 'Kishmish vatkana' also has a parent-offspring relationship with the seedless table grape 'Sultanina'. In addition, the distant genetic relatedness to rootstocks, some of which are derived from North American species resistant to powdery mildew and have been used worldwide to guard against phylloxera since the late 1800's, argues against REN1 being infused into Vitis vinifera from a

  2. Efficiency of Several Fungicides to Control Wheat Powdery Mildew%几种杀菌剂对小麦白粉病的防治效果

    Institute of Scientific and Technical Information of China (English)

    杨共强; 宋玉立; 何文兰; 孙静

    2011-01-01

    为了筛选对小麦白粉病有效的防治药剂,在小麦白粉病发病初期,选用7.5%氟环唑乳油、50%醚菌酯干悬浮剂等13种杀菌剂进行喷雾,25d后调查发病情况.结果表明,13种杀菌剂对小麦白粉病均有一定的防效,为40.5%~86.8%.其中50%醚菌酯干悬浮剂、7.5%氟环唑乳油、25%丙环唑乳油3种药剂对小麦白粉病的防效最好,分别为86.8%、85.1%、79.3%其次为50%禾瑞水分散粒剂、5%烯肟菌胺乳油、12.5%烯唑醇可湿性粉剂、15%氯啶菌酯乳油、20%戊唑醇·烯肟菌胺悬浮剂和15%三唑酮可湿性粉剂6种药剂,防效在60.8%~69.3%.以上9种药剂对小麦白粉病有较好的防治效果,可在生产上推广应用.%In order to screen effective fungicides to control wheat powdery mildew, the efficacy of 13 fungicides was measured against wheat powdery mildew in the fields. The fungicides were spayed at the early stage of the disease and the disease condition was investigated after 25 days. The results showed that 13 fungicides had some control effects of 40. 5%-86. 8%. Three fungicides, 50% Kresoxim-methyl DF,7. 5% Epoxiconazole EC and 25% Propiconazole EC had best control effect (86. 8%, 85. 1% and 79. 3%, respectively), and the other six fungicides, 50% Cyprodinil WG, 5% SYP-1620 EC,12. 5% Diniconazole WP,15% SYP-7017 EC, 20% Tebuconazole ~ SYP-1620 SC and 15% Triadimefon WP also had good control effect (69. 3%, 66. 7%, 65.0%, 63. 6%, 62. 4% and 60. 8% .respectively). The nine fungicides were recommended for use in wheat production.

  3. The knock-down of the expression of MdMLO19 reduces susceptibility to powdery mildew (Podosphaera leucotricha) in apple (Malus domestica).

    Science.gov (United States)

    Pessina, Stefano; Angeli, Dario; Martens, Stefan; Visser, Richard G F; Bai, Yuling; Salamini, Francesco; Velasco, Riccardo; Schouten, Henk J; Malnoy, Mickael

    2016-10-01

    Varieties resistant to powdery mildew (PM; caused by Podosphaera leucotricha) are a major component of sustainable apple production. Resistance can be achieved by knocking-out susceptibility S-genes to be singled out among members of the MLO (Mildew Locus O) gene family. Candidates are MLO S-genes of phylogenetic clade V up-regulated upon PM inoculation, such as MdMLO11 and 19 (clade V) and MdMLO18 (clade VII). We report the knock-down through RNA interference of MdMLO11 and 19, as well as the complementation of resistance with MdMLO18 in the Arabidopsis thaliana triple mlo mutant Atmlo2/6/12. The knock-down of MdMLO19 reduced PM disease severity by 75%, whereas the knock-down of MdMLO11, alone or in combination with MdMLO19, did not result in any reduction or additional reduction of susceptibility compared with MdMLO19 alone. The test in A. thaliana excluded a role for MdMLO18 in PM susceptibility. Cell wall appositions (papillae) were present in both PM-resistant and PM-susceptible plants, but were larger in resistant lines. No obvious negative phenotype was observed in plants with mlo genes knocked down. Apparently, MdMLO19 plays the pivotal role in apple PM susceptibility and its knock-down induces a very significant level of resistance. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  4. Fungal species that cause powdery mildew in greenhouse-grown cucumber and melon in Paraná State, Brazil=Espécies de fungos que causam oídio em casas de vegetação cultivadas com pepino e melão no Estado do Paraná, Brasil

    Directory of Open Access Journals (Sweden)

    Dauri José Tessmann

    2012-07-01

    Full Text Available The powdery mildew caused by Oidium spp. is an important disease for several crops of the Cucurbitaceae family. Although the teleomorphs, Podosphaera xanthii and Golovinomyces cichoracearum, currently have already been described as the causal agents of powdery mildew in Brazil, only P. xanthii is considered the main causal agent of powdery mildew field epidemics. The objective of this work was to identify and determine the prevalence of the species causing powdery mildew in cucumber (Cucumis sativus and melon (Cucumis melo var. reticulatus grown in greenhouses in the State of Paraná in Brazil. The morphological traits of the conidial stages, such as the presence of fibrosin bodies and a germinative tube, were used to identify the species. Leaves exhibiting high severity of powdery mildew were collected from plants of 13 plastic greenhouses during different seasons in 2003/2004 and in different regions of Paraná State. In all environments, a significant prevalence of P. xanthii (80-100% was observed affecting parthenocarpic or ordinary cucumber and melon. Golovinomyces cichoracearum was observed in six greenhouses, with up to 20% of conidia of this species on the samples.O oidio, causado por Oidium sp. é uma importante doença para espécies de plantas cultivadas da família das cucurbitáceas. Apesar das espécies teleomórficas Podosphaera xanthii e Golovinomyces cichoracearum já terem sido citadas como causadoras de oídio no Brasil, geralmente em trabalhos publicados atualmente tem-se referenciado somente a P. xanthii como agente causal dessa doença em cucurbitáceas em cultivo convencional. Por isso, este trabalho teve como objetivo identificar e quantificar a freqüência de ocorrência dessas duas espécies causadoras de oídio nas culturas de pepino (Cucumis sativus e melão nobre (Cucumis melo var. reticulatus conduzidas em estufas plásticas no Estado do Paraná. Para a identificação de P. xanthii e G. cichoracearum utilizaram

  5. Meteorological Factors and its Forecast on Wheat Powdery Mildew Occurrence in China%小麦白粉病发生气象条件和气象预报研究进展

    Institute of Scientific and Technical Information of China (English)

    郑秋红; 杨霏云; 朱玉洁

    2013-01-01

    基于已有成果,采用影响事实检测法,系统分析和汇总气象条件对小麦白粉病影响的规律,对气象因子在国内小麦白粉病预报中的应用进行综述,指出当前研究存在的问题,并对未来发展进行展望.已有研究表明,夏季气温偏低对白粉病病菌的越夏有利;秋冬季及早春气温偏高或阴雨日偏多利于病情发展,但雨水过多且集中则不利于病害发展;冬小麦生长中后期高温干旱会抑制病情发展;日照少则利于白粉病流行;病菌借助大气环流完成异地传播.关于气象因子对小麦白粉病影响的研究多基于田间观测,通过与气象资料对比分析,建立小麦白粉病发生发展与各气象因子及因子组合间的定量关系.有关小麦白粉病的气象预报分定性和定量两大类:定性预报一般采用指标预测法;定量预报以数理统计方法应用为多,人工神经网络法、模糊数学法和灰色系统理论也有应用.目前国内小麦白粉病预报研究中尚存在数据资料有限、指标选择不当、模拟方法仅限于黑箱和灰箱模型、研究结果地域性强、实用性较差等问题.机理模型的研究极少,未来亟待开展.%The impact of meteorological factors to wheat powdery mildew was analyzed based on the previous researches,by using of the method of detecting facts.Application of meteorological factors to wheat powdery mildew forecast was summarized,and problems in current research were pointed out and future research trend was suggested.Previous researches showed that low summer temperature was conducive to powdery mildew survival.Higher temperature and more precipitation in autumn,winter and early spring were conducive to the occurrence and development of powdery mildew.But overmuch rainfall was not conducive to the development of powdery mildew.High temperature over 25 ℃ and drought could inhibit disease development.Low sunshine was conducive to the development of powdery

  6. Compromised Photosynthetic Electron Flow and H2O2 Generation Correlate with Genotype-Specific Stomatal Dysfunctions during Resistance against Powdery Mildew in Oats.

    Science.gov (United States)

    Sánchez-Martín, Javier; Montilla-Bascón, Gracia; Mur, Luis A J; Rubiales, Diego; Prats, Elena

    2016-01-01

    Stomatal dysfunction known as "locking" has been linked to the elicitation of a hypersensitive response (HR) following attack of fungal pathogens in cereals. We here assess how spatial and temporal patterns of different resistance mechanisms, such as HR and penetration resistance influence stomatal and photosynthetic parameters in oat (Avena sativa) and the possible involvement of hydrogen peroxide (H2O2) in the dysfunctions observed. Four oat cultivars with differential resistance responses (i.e., penetration resistance, early and late HR) to powdery mildew (Blumeria graminis f. sp. avenae, Bga) were used. Results demonstrated that stomatal dysfunctions were genotype but not response-type dependent since genotypes with similar resistance responses when assessed histologically showed very different locking patterns. Maximum quantum yield (Fv/Fm) of photosystem II were compromised in most Bga-oat interactions and photoinhibition increased. However, the extent of the photosynthetic alterations was not directly related to the extent of HR. H2O2 generation is triggered during the execution of resistance responses and can influence stomatal function. Artificially increasing H2O2 by exposing plants to increased light intensity further reduced Fv/Fm ratios and augmented the patterns of stomatal dysfunctions previously observed. The latter results suggest that the observed dysfunctions and hence a cost of resistance may be linked with oxidative stress occurring during defense induced photosynthetic disruption.

  7. Characterization of RAPD Markers, and the RFLP Marker Linked to Powdery Mildew Resistance Gene Derived from Different Accessions of H. villosa

    Institute of Scientific and Technical Information of China (English)

    LI Hui; CHEN Xiao; SHI Ai-nong; KONG Fan-jing; S Leath; J P Murphy; JIA Xu

    2005-01-01

    The analysis was carried out on performance of the resistance gene from Haynaldia villosa accession of the former Soviet Union to different isolates of Bluemerie graminis. Polymorphisms were revealed between 6D/6V substitution line Pm930640and its pedigree parents using five RAPD markers of OPAN031700, OPAI017oo, OPAL03750, OPAD07480 and OPAG1558oscreened out from 120 random 10-mers primers. Three RAPD markers of OPAN03, OPAI01 and OPAL03 were linked with the resistance gene by analysis of F2 population of Chancellor×Pm930640. Analysis of 29 wheat lines including part of lines conferring the known genes from Pm1 to Pm20 respectively, lines conferring resistance gene from two H. villosaaccessions and the related wheat parents, were analyzed and the results showed that these markers not only linked to thegene resistant to powdery mildew from H. villosa, but also detected different genetic backgrounds. OPAL03750 can beused as the marker to distinguish the different resistant lines from two H. villosa accessions because it was only observedin the materials from H. villosa of the former Soviet Union. RFLP analysis also showed the polymorphisms between twoH. villosa accessions and their derived resistant lines.

  8. A stilbene synthase allele from a Chinese wild grapevine confers resistance to powdery mildew by recruiting salicylic acid signalling for efficient defence

    Science.gov (United States)

    Jiao, Yuntong; Xu, Weirong; Duan, Dong; Wang, Yuejin; Nick, Peter

    2016-01-01

    Stilbenes are central phytoalexins in Vitis, and induction of the key enzyme stilbene synthase (STS) is pivotal for disease resistance. Here, we address the potential for breeding resistance using an STS allele isolated from Chinese wild grapevine Vitis pseudoreticulata (VpSTS) by comparison with its homologue from Vitis vinifera cv. ‘Carigane’ (VvSTS). Although the coding regions of both alleles are very similar (>99% identity on the amino acid level), the promoter regions are significantly different. By expression in Arabidopsis as a heterologous system, we show that the allele from the wild Chinese grapevine can confer accumulation of stilbenes and resistance against the powdery mildew Golovinomyces cichoracearum, whereas the allele from the vinifera cultivar cannot. To dissect the upstream signalling driving the activation of this promoter, we used a dual-luciferase reporter system in a grapevine cell culture. We show elevated responsiveness of the promoter from the wild grape to salicylic acid (SA) and to the pathogen-associated molecular pattern (PAMP) flg22, equal induction of both alleles by jasmonic acid (JA), and a lack of response to the cell death-inducing elicitor Harpin. This elevated SA response of the VpSTS promoter depends on calcium influx, oxidative burst by RboH, mitogen-activated protein kinase (MAPK) signalling, and JA synthesis. We integrate the data in the context of a model where the resistance of V. pseudoreticulata is linked to a more efficient recruitment of SA signalling for phytoalexin synthesis. PMID:27702992

  9. 20%烯肟菌胺·戊唑醇悬浮剂对辣椒白粉病的防治效果%Control Effect of SYP-1620·Tebuconazole Suspension Concentrate against Capsicum Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    何献声; 姚娜

    2011-01-01

    [Aims] Capsicum powdery mildew is an important plant disease. It induces crop's yield loss and quality drop. Chemical control is a good means to control the disease, such as triadimefon, difenoconazole and flusilazole. [Results] In field trial, SYP-1620-tebuconazole 20% SC had excellent control effect against capsicum powdery mildew. At 100-200 g a.I./ha, by using the mixed fungicide two or three times through spraying means, the control effect was better than kresoxim-methyl and triadimefon. The mixed fungicide was safe to capsicum. [Conclusions] SYP-1620-tebuconazole 20% SC has good control effect against powdery mildew and good to capsioum security.%[目的]白粉病是影响辣椒正常生长的重要病害,严重影响辣椒的产量和品质.化学防治是控制辣椒白粉病的重要措施,多种药剂,如三唑酮、苯醚甲环唑、氟硅唑等均可用于该病害的防治.[结果]田间小区试验结果一致表明:20%烯肟菌胺·戊唑醇悬浮剂对辣椒白粉病具有优异的防治效果,100~200 mg/L处理剂量,施药2~3次,对辣椒白粉病的防治效果在85%以上,优于醚菌酯和三唑酮.在试验剂量下,对供试作物辣椒安全.[结论]20%烯肟菌胺·戊唑醇悬浮剂可用于田间辣椒白粉病的防治,具备较好的防治效果和安全性.

  10. 几种药剂对葡萄白粉病的防治效果%Efficacy of Several Fungicides for Control of Grape Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    门光耀; 任毓忠; 吉丽丽; 张涛; 刘培源; 韩宏伟; 李国英

    2011-01-01

    [Objective] Grape powdery mildew ( GPM), incited by Uncinula necator,is a major disease and causes yield reductions to grape growing in Xinjiang. Use of fungicides is the primary method of controlling GPM.The objective of this research was to evaluate the efficacy of several fungicides for control of GPM . [Method]In vivo laboratory assay methods used to determine the sensitivity of conidia germination to fungicides, and field protection and treating trials were conducted to evaluate the effect of foliar fungicides on CPM . [ Result] The results of laboratory experiments showed that 2. 00 g/L Lime - Sulfur crystal, 0. 50 g/L Myclobutanil WP, 0. 15 g/L Triadimefon WP were the most effective in inhibiting conidia germination of Uacinula necator, and their inhibition can reach 96.57%, 93.71% and 85.71% , respectively. Any of the fungicide treatment by using 0. 15 g/L Triadimefon WP, 2 . 00 9,L Lime - SuKur crystal, 0.06 g/L Diniconazole WP and 0. 11g/L Tebuconazole is remarkably better than other reagents in prevention or field treatment. The prevention and treatment efficiency can reach 88 . 85 %/70 . 17 % , 87 .88 %/77 .05% , 82 . 86 %/78 . 62 % respectively . The preventive functions of 0 . 50 g/ L Myclobutanil WP and 0. 11 g/L Tebuconazole SC are quite satisfactory. [Conclusion] Thereby, the above -mentioned fungicides can be used effectively in controlling grape powdery mildew before and during the disease .%[目的]葡萄白粉病(Uncinula necator)是造成新疆葡萄减产的重要病害之一,杀菌剂的应用是控制该病的主要方法,确定几种杀菌剂对葡萄白粉病的防治效果.[方法]通过室内药剂筛选、田间保护与治疗试验等方法,了解各供试杀菌剂之间对白粉病防治效果的异同,并采用Duncan新复极差法对不同处理的防效进行差异显著性分析,从而选出防效较好的药剂.[结果]2.00 g/L石硫合剂结晶、0.50 g/L冠信WP、0.15 g/L三唑酮WP能明显抑制分生

  11. Biological characteristics of tobacco powdery mildew pathogen%烟草白粉病菌的生物学特性研究

    Institute of Scientific and Technical Information of China (English)

    邢荷荷; 梁晨; 于静; 张成省; 孔凡玉; 王凤龙

    2015-01-01

    采用水琼脂玻片法测定不同的环境和营养因子对烟草白粉病菌Golovinomyces orontii (Castagne) V. P. Heluta分生孢子萌发的影响。研究表明:分生孢子萌发的最适温度为25℃,致死温度为42℃10min;适宜相对湿度范围为93%-100%;对光照要求不严格;在pH5-pH8范围分生孢子萌发率无显著差异;在碳氮源利用方面,该菌对供试碳源均能利用,其中果糖的效果最好;但供试氮源对分生孢子均有不同程度的抑制作用。%Water agar slide method was used for measuring the effect of different environmental and nutritional factors on conidia germination of tobacco powdery mildew pathogenGolovinomyces orontii (Castagne) V. P. Heluta. Results indicated that optimum temperature for germination was 25℃, lethal temperature for conidia was 42℃ 10min and optimal relative humidity was 93%-100%. It was also found that conidia germination had no strict requirement for illumination. There is no significant difference in conidia germination rates within pH range of 5 to 8. The pathogen could utilize all tested carbon sources, among which fructose was the best. Tested nitrogen sources had different inhibition effect on conidia germination.

  12. Phosphorus supply, arbuscular mycorrhizal fungal species, and plant genotype impact on the protective efficacy of mycorrhizal inoculation against wheat powdery mildew.

    Science.gov (United States)

    Mustafa, G; Randoux, B; Tisserant, B; Fontaine, J; Magnin-Robert, M; Lounès-Hadj Sahraoui, A; Reignault, Ph

    2016-10-01

    A potential alternative strategy to chemical control of plant diseases could be the stimulation of plant defense by arbuscular mycorrhizal fungi (AMF). In the present study, the influence of three parameters (phosphorus supply, mycorrhizal inoculation, and wheat cultivar) on AMF protective efficiency against Blumeria graminis f. sp. tritici, responsible for powdery mildew, was investigated under controlled conditions. A 5-fold reduction (P/5) in the level of phosphorus supply commonly recommended for wheat in France improved Funneliformis mosseae colonization and promoted protection against B. graminis f. sp. tritici in a more susceptible wheat cultivar. However, a further decrease in P affected plant growth, even under mycorrhizal conditions. Two commercially available AMF inocula (F. mosseae, Solrize®) and one laboratory inoculum (Rhizophagus irregularis) were tested for mycorrhizal development and protection against B. graminis f. sp. tritici of two moderately susceptible and resistant wheat cultivars at P/5. Mycorrhizal levels were the highest with F. mosseae (38 %), followed by R. irregularis (19 %) and Solrize® (SZE, 8 %). On the other hand, the highest protection level against B. graminis f. sp. tritici was obtained with F. mosseae (74 %), followed by SZE (58 %) and R. irregularis (34 %), suggesting that inoculum type rather than mycorrhizal levels determines the protection level of wheat against B. graminis f. sp. tritici. The mycorrhizal protective effect was associated with a reduction in the number of conidia with haustorium and with an accumulation of polyphenolic compounds at B. graminis f. sp. tritici infection sites. Both the moderately susceptible and the most resistant wheat cultivar were protected against B. graminis f. sp. tritici infection by F. mosseae inoculation at P/5, although the underlying mechanisms appear rather different between the two cultivars. This study emphasizes the importance of taking into account the considered

  13. Flor Revisited (Again):eQTL and Mutational Analysis of NB-LRR Mediated Immunity to Powdery Mildew in Barley

    Institute of Scientific and Technical Information of China (English)

    Roger Wise; Priyanka Surana; Greg Fuerst; Ruo Xu; Divya Mistry; Julie Dickerson; Dan Nettleton

    2014-01-01

    Genes encoding early signaling events in pathogen defense often are identiifed only by their phenotype. Such genes involved in barley-powdery mildew interactions includeMla, specifying race-speciifc resistance;Rar1(Required for Mla12-speciifed resistance1), andRom1 (Restoration of Mla-speciifed resistance1). The HSP90-SGT1-RAR1 complex appears to function as chaperone in MLA-speciifed resistance, however, much remains to be discovered regarding the precise signaling underlying plant immunity. Genetic analyses of fast-neutron mutants derived from CI 16151 (Mla6) uncovered a novel locus, designated Rar3(Required for Mla6-specified resistance3).Rar3 segregates independent ofMla6 andRar1, andrar3 mutants are susceptible toBlumeria graminis f. sp.hordei (Bgh) isolate 5874 (AVRa6), whereas, wild-type progenitor plants are resistant. Comparative expression analyses of therar3 mutantvs. its wild-type progenitor were conductedvia Barley1 GeneChip and GAIIx paired-end RNA-Seq. Whereas Rar1affects transcription of relatively few genes; Rar3appearstoinlfuence thousands, notably in genes controlling ATP binding, catalytic activity, transcription, and phosphorylation; possibly membrane bound or in the nucleus. eQTL analysis of a segregating doubled haploid population identiifed over two-thousand genes as being regulated byMla(q value/FDR=0.00001), a subset of which are signiifcant inRar3 interactions. The intersection of datasets derived frommla-loss-of-function mutants,Mla-associated eQTL, andrar3-mediated transcriptome reprogramming are narrowing the focus on essential genes required forMla-speciifed immunity.

  14. Fine mapping, phenotypic characterization and validation of non-race-specific resistance to powdery mildew in a wheat-Triticum militinae introgression line.

    Science.gov (United States)

    Jakobson, Irena; Reis, Diana; Tiidema, Anu; Peusha, Hilma; Timofejeva, Ljudmilla; Valárik, Miroslav; Kladivová, Monika; Simková, Hana; Doležel, Jaroslav; Järve, Kadri

    2012-08-01

    Introgression of several genomic loci from tetraploid Triticum militinae into bread wheat cv. Tähti has increased resistance of introgression line 8.1 to powdery mildew in seedlings and adult plants. In our previous work, only a major quantitative trait locus (QTL) on chromosome 4AL of the line 8.1 contributed significantly to resistance, whereas QTL on chromosomes 1A, 1B, 2A, 5A and 5B were detected merely on a suggestive level. To verify and characterize all QTLs in the line 8.1, a mapping population of double haploid lines was established. Testing for seedling resistance to 16 different races/mixtures of Blumeria graminis f. sp. tritici revealed four highly significant non-race-specific resistance QTL including the main QTL on chromosome 4AL, and a race-specific QTL on chromosome 5B. The major QTL on chromosome 4AL (QPm.tut-4A) as well as QTL on chromosome 5AL and a newly detected QTL on 7AL were highly effective at the adult stage. The QPm.tut-4A QTL accounts on average for 33-49 % of the variation in resistance in the double haploid population. Interactions between the main QTL QPm.tut-4A and the minor QTL were evaluated and discussed. A population of 98 F(2) plants from a cross of susceptible cv. Chinese Spring and the line 8.1 was created that allowed mapping the QPm.tut-4A locus to the proximal 2.5-cM region of the introgressed segment on chromosome 4AL. The results obtained in this work make it feasible to use QPm.tut-4A in resistance breeding and provide a solid basis for positional cloning of the major QTL.

  15. ITS Sequence Analysis of Several Powdery Mildew from Henan Province%河南省几种白粉菌的ITS序列分析

    Institute of Scientific and Technical Information of China (English)

    马原松; 裴冬丽; 王文静; 李成伟

    2012-01-01

    采用改良CTAB法提取河南省5种植物白粉菌DNA,扩增其rDNA内转录间隔区(ITS)序列,并进行亲缘关系分析.结果表明:寄生于凤仙、豇豆和菊芋的叉丝单囊壳属白粉菌,其ITS序列聚在一支,遗传距离小,亲缘关系近;寄生在大叶黄杨上的冬青卫矛白粉菌和番茄上的新番茄粉孢菌,其ITS序列聚在另外一支.此分析结果与5种白粉菌的形态学分类结果相一致,说明ITS序列分析技术可以为病原菌的分类鉴定及系统发育等研究提供依据.%The DNA of five powdery mildews from Henan province were extracted by modified CTAB method,and then the rDNA ITS sequences were amplified to analyze the phylogenetic relationship. The result showed that three ITS sequences of Podosphaera section from Impatiens balsamina ,Vigna un-guiculata and Helianthus tuberosus were in one cluster for their small genetic distances and close genetic relationships, and the ITS sequences of Erysiphe sp. from Euonymus japonicus and Odium neolycopersici from tomato were in another cluster,which was consistent with the classification by the morphological characteristics. Therefore, the application of ITS sequences can provide important theoretical basis for pathogen classification and phylogenetic relationship analysis.

  16. Silicon-mediated resistance of Arabidopsis against powdery mildew involves mechanisms other than the salicylic acid (SA)-dependent defence pathway.

    Science.gov (United States)

    Vivancos, Julien; Labbé, Caroline; Menzies, James G; Bélanger, Richard R

    2015-08-01

    On absorption by plants, silicon (Si) offers protection against many fungal pathogens, including powdery mildews. The mechanisms by which Si exerts its prophylactic role remain enigmatic, although a prevailing hypothesis suggests that Si positively influences priming. Attempts to decipher Si properties have been limited to plants able to absorb Si, which excludes the model plant Arabidopsis because it lacks Si influx transporters. In this work, we were able to engineer Arabidopsis plants with an Si transporter from wheat (TaLsi1) and to exploit mutants (pad4 and sid2) deficient in salicylic acid (SA)-dependent defence responses to study their phenotypic response and changes in defence expression against Golovinomyces cichoracearum (Gc) following Si treatment. Our results showed that TaLsi1 plants contained significantly more Si and were significantly more resistant to Gc infection than control plants when treated with Si, the first such demonstration in a plant transformed with a heterologous Si transporter. The resistant plants accumulated higher levels of SA and expressed higher levels of transcripts encoding defence genes, thus suggesting a role for Si in the process. However, TaLsi1 pad4 and TaLsi1 sid2 plants were also more resistant to Gc than were pad4 and sid2 plants following Si treatment. Analysis of the resistant phenotypes revealed a significantly reduced production of SA and expression of defence genes comparable with susceptible controls. These results indicate that Si contributes to Arabidopsis defence priming following pathogen infection, but highlight that Si will confer protection even when priming is altered. We conclude that Si-mediated protection involves mechanisms other than SA-dependent defence responses.

  17. Transcriptional expression of Stilbene synthase genes are regulated developmentally and differentially in response to powdery mildew in Norton and Cabernet Sauvignon grapevine.

    Science.gov (United States)

    Dai, Ru; Ge, Hui; Howard, Susanne; Qiu, Wenping

    2012-12-01

    Stilbenic compounds are natural phytoalexins that have antimicrobial activities in plant defense against pathogens. Stilbene synthase (STS) is the key enzyme that catalyzes the biosynthesis of stilbenic compounds. Grapevine genome contains a family of preliminarily annotated 35 STS genes, the regulation of each STS gene needs to be studied to define their roles. In this study, we selected eight STS genes, STS8, STS27/31, STS16/22, STS13/17/23, and applied quantitative polymerase chain reaction (qPCR) to characterize their transcriptional expression profiles in leaf tissues upon infection by the powdery mildew fungus (PM), Erysiphe necator (Schw.) Burr. Their transcripts were also compared in young and old leaves as well as in the berry skin at five developmental stages in Vitis vinifera 'Cabernet Sauvignon' and Vitis aestivalis 'Norton'. The results showed that transcripts of selected STS genes increased significantly in Cabernet Sauvignon leaves at 24 and 48 h post inoculation with PM spores and remained unchanged in Norton leaves in response to the PM infection. Transcripts of STS8, STS27/31 and STS13/17/23 were more abundant in the old leaves of Norton than in Cabernet Sauvignon. STS genes showed lower expression levels in young leaves than in old leaves. Transcript levels of the eight STS genes increased drastically in the berry skin of Cabernet Sauvignon and Norton post véraison. In addition, the content of trans-resveratrol in the berry skin rapidly increased post véraison and reached the highest level at harvest. These assays demonstrated that individual STS genes are regulated differentially in response to PM infection and during development in the two grape varieties. The present study yields basic knowledge for further investigation of the regulation and function of each STS gene in grapevine and provides experimental evidences for the functional annotation of the STS gene family in the grapevine genome.

  18. 兼抗全蚀病和白粉病小麦新种质的创制与鉴定%Development and Characterization of Wheat Lines with Resistance to Take-All and Powdery Mildew Diseases

    Institute of Scientific and Technical Information of China (English)

    祝秀亮; 李钊; 杜丽璞; 徐惠君; 杨丽华; 庄洪涛; 马翎健; 张增艳

    2012-01-01

    "Take-all", primarily caused by Gaeumannomyces graminis var. Tritici (Ggt), and powdery mildew, mainly caused by Blumeria graminis f. Sp. Tritici (Bgt), are important diseases of wheat (Triticum aestivum L.) worldwide. The wheat cultivar Yangmai 18 carrying a powdery mildew resistance gene Pm21, shows broad-spectrum resistance to powdery mildew. We have isolated a lipid transfer protein gene TaLTPS from wheat. To study the role of TaLTP5 in wheat defense responses to the major pathogens of take-all, we introduced this gene into Yangmai 18 via bombarding the particle containing the TaLTPS expressing vector pA25-TaLTP5. The TaLTPS transgenic wheat plants from T0 to T3 generations were subjected to PCR, Southern blot, RT-PCR, and Q-RT-PCR analyses. We also evaluated the disease resistances of the TaLTPS transgenic plants against inoculating Ggt and Bgt. The PCR and Southern blotting results showed that the alien TaLTP5 was transferred and integrated into the genomes of three transgenic wheat lines, and inherited stably in the transgenic wheat lines. The RT-PCR and Q-RT-PCR results indicated that the introduced TaLTPS was over-expressed in transgenic wheat lines, which showed significantly-enhanced resistance to take-all, suggesting that TaLTPS gene is involved in the defense response to Ggt infection. In addition, the resistance of transgenic lines to powdery mildew was not influenced by the introduced gene TaLTPS. Thus, TaLTPS transgenic wheat Yangmai 18 exhibits resistance to both "Take-all" and powdery mildew.%TaLTP5是从小麦中分离到的一个脂质转移蛋白编码基因.利用基因枪介导法将TaLTP5表达载体pA25-TaLTP5转入抗白粉病的小麦品种扬麦18(含抗白粉病基因Pm21)中,旨在选育兼抗全蚀病和白粉病的小麦新种质.对转基因小麦T0~T3代植株中引入的TaLTP5基因进行分子检测和抗病性鉴定.PCR检测、Southern杂交分析结果表明,外源TaLTP5基因已转入、整合到3个转基因小麦株系

  19. Study on the Resistance of 60 Cashew Clones to Powdery Mildew Disease in Mozambique%莫桑比克60个腰果品系对腰果白粉病的抗性研究

    Institute of Scientific and Technical Information of China (English)

    王金辉; 张中润; 梁李宏; Americo Uaciquete; 黄伟坚; 黄海杰

    2013-01-01

    为研究莫桑比克腰果品系对白粉病的抗性,筛选出对白粉病具有抗性的腰果品系.在莫桑比克楠普拉省,调查了白粉病在60个腰果品系果实上的为害状况.结果显示,同一条件下,各腰果品系坚果上的白粉病为害程度差异很大.其中,品系AC34和4.2VM受白粉病的为害程度最低,其次为AZA 17/79、B4、H1和M96-2.3VM,其余品系的坚果为害率和为害指数相对较高.根据笔者调查中腰果对白粉病抗性的评价标准,60个腰果品系中,分别有高抗品系6个、抗性品系1个、中抗品系9个、感病品系21个、高感品系23个.感病品系和高感品系共占调查总数的73.3%,说明莫桑比克推广种植的腰果品系对白粉病抗性普遍较差.%In order to study the resistance of cashew to powdery mildew disease in Mozambique, and find the cashew clones that are resistant to powdery mildew disease. In Nampula Province of Mozambique, the damage of cashew fruit of 60 cashew clones caused by powdery mildew disease was investigated. The result indicated that, under the same condition, the cashew nut damage degree of different cashew clones were different. The damage degree of AC34 and 4.2VM were the lowest. The next were AZA17/79, B4, H1 and M96-2.3VM. The damage rates and damage indexes of other clones were higher relatively. According to the resistance evaluation criteria of cashew to powdery mildew disease in this paper, there were 6 high resistant clones, 1 resistant clone, 9 medium resistant clones, 21 susceptible clones and 23 high susceptible clones in the 60 investigated cashew clones. The susceptible and high susceptible clones account for 73.3% of the total samples. The most cashew clones in Mozambique were low resistant to powdery mildew disease.

  20. Characterization and Genetic Analysis of a Novel Light-Dependent Lesion Mimic Mutant, lm3, Showing Adult-Plant Resistance to Powdery Mildew in Common Wheat.

    Directory of Open Access Journals (Sweden)

    Fang Wang

    Full Text Available Lesion mimics (LMs that exhibit spontaneous disease-like lesions in the absence of pathogen attack might confer enhanced plant disease resistance to a wide range of pathogens. The LM mutant, lm3 was derived from a single naturally mutated individual in the F1 population of a 3-1/Jing411 cross, backcrossed six times with 3-1 as the recurrent parent and subsequently self-pollinated twice. The leaves of young seedlings of the lm3 mutant exhibited small, discrete white lesions under natural field conditions. The lesions first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. The lesions were initiated through light intensity and day length. Histochemical staining revealed that lesion formation might reflect programmed cell death (PCD and abnormal accumulation of reactive oxygen species (ROS. The chlorophyll content in the mutant was significantly lower than that in wildtype, and the ratio of chlorophyll a/b was increased significantly in the mutant compared with wildtype, indicating that lm3 showed impairment of the biosynthesis or degradation of chlorophyll, and that Chlorophyll b was prone to damage during lesion formation. The lm3 mutant exhibited enhanced resistance to wheat powdery mildew fungus (Blumeria graminis f. sp. tritici; Bgt infection, which was consistent with the increased expression of seven pathogenesis-related (PR and two wheat chemically induced (WCI genes involved in the defense-related reaction. Genetic analysis showed that the mutation was controlled through a single partially dominant gene, which was closely linked to Xbarc203 on chromosome 3BL; this gene was delimited to a 40 Mb region between SSR3B450.37 and SSR3B492.6 using a large derived segregating population and the available Chinese Spring chromosome 3B genome sequence. Taken together, our results provide information regarding the identification of a novel wheat LM gene, which will facilitate the additional fine

  1. Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.

    Directory of Open Access Journals (Sweden)

    Aili Li

    Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.

  2. Powdery mildew of Ruta graveolens in Brazil caused by Oidiopsis haplophylli Oídio de Ruta graveolens no Brasil causado por Oidiopsis haplophylli

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    José Ricardo Liberato

    2006-03-01

    Full Text Available Oidiopsis haplophylli is described causing powdery mildew on Ruta graveolens for the first time in Brazil (Viçosa, MG. The fungus causes yellowing of infected leaves accompanied by the presence of a whitish mycelial colony abaxially. The following combination of characters typical of this species was observed on the specimens collected in Viçosa: mycelium hypophyllous, hemiendophytic (partly external and partly internal, entering the leaves through the stomata; conidiophores hypophyllous, produced from the internal mycelium emerging through the stomata, cylindrical, hyaline, smooth; conidia, isolate, dimorphic - primary conidia lanceolate, 66.5-91.5 x 11.0-20.0 mm l/w ratio 3.5-6.2, secondary conidia cylindrical with rounded ends, 57.0-81.5 x 13.5-20.0 mm, l/w ratio 3.1 - 5.3, aseptate, hyaline, smooth.Oidiopsis haplophylli é relatado causando oídio em arruda (Ruta graveolens pela primeira vez no Brasil (Viçosa, MG. O fungo causa um amarelecimento de folhas de arruda sem bordos definidos acompanhado de cobertura fúngica branca na superfície abaxial. O seguinte conjunto de características, típico desta espécie foi observado nos espécimes coletados em Viçosa: presença de micélio hemiendofítico (parcialmente interno e parcialmente externo, tênue a denso com penetração das folhas através dos estômatos; conidióforos originando do micélio interno, emergindo através dos estômatos, cilíndricos, hialinos, lisos; conídios unicelulares, hialinos, produzidos isoladamente, dimórficos - conídios primários lanceolados, 66,5-91,5 x 11,0-20,0 mm, razão c/l 3,5-6,2, conídios secondários cilíndricos com extremidades arredondadas, 57,0-81,5 x 13,5-20,0 mm, razão c/l 3,1-5,3.

  3. Rapid Staining Method to Detect and Identify Downy Mildew (Peronospora belbahrii in Basil

    Directory of Open Access Journals (Sweden)

    Adolfina R. Koroch

    2013-07-01

    Full Text Available Premise of the study: Demand for fresh-market sweet basil continues to increase, but in 2009 a new pathogen emerged, threatening commercial field/greenhouse production and leading to high crop losses. This study describes a simple and effective staining method for rapid microscopic detection of basil downy mildew (Peronospora belbahrii from leaves of basil (Ocimum basilicum. Methods and Results: Fresh leaf sections infected with P. belbahrii were placed on a microscope slide, cleared with Visikol™, and stained with iodine solution followed by one drop of 70% sulfuric acid. Cell walls of the pathogen were stained with a distinct coloration, providing a high-contrast image between the pathogen and plant. Conclusions: This new staining method can be used successfully to identify downy mildew in basil, which then can significantly reduce its spread if identified early, coupled with mitigation strategies. This technique can facilitate the control of the disease, without expensive and specialized equipment.

  4. Control Efficacy of Several Fungicides to Wheat Powdery Mildew%几种杀菌剂对小麦白粉病的防治效果

    Institute of Scientific and Technical Information of China (English)

    高海峰; 努尔孜亚·亚力买买提; 李广阔; 高永红; 雷钧杰; 王锁牢

    2013-01-01

    [目的]通过室内及田间试验,筛选对小麦白粉病防治效果较好的化学药剂及合理的使用方法.[方法]采取室内盆栽接菌试验及田间小区试验相结合的方式进行,在植株发病后喷雾防治,药后定期调查防治效果.[结果]药后10 d,250g/L丙环唑乳油112.5 g a.i/hm2处理在室内及田间试验对白粉病的防效分别为82.02%和74.02%,防治效果优于其它药剂处理的防效;其次是25%三唑酮可湿性粉剂135 g a.i/hm2处理,室内及田间试验防效分别为81.84%和67.24%;400 g/L氟硅唑乳油48 g a.i/hm2处理的室内及田间试验防效分别为69.25%和67.99%,对白粉病的防效也较好.25%乙嘧酚水悬浮剂187.5 g a.i/hm2处理、250 g/L已唑醇悬浮剂18.75 g a.i/hm2处理、10%苯醚菌酯悬浮剂12 g a.i/hm2处理在室内试验中对白粉病防治效果较好,但田间小区试验中防效略低.[结论]250g/L丙环唑乳油112.5 g a.i/hm2处理、25%三唑酮可湿性粉剂135 g a.i/hm2处理、400 g/L氟硅唑乳油48 g a.i/hm2处理可有效控制小麦白粉病的发生及危害,且对小麦生长安全,可在大田合理轮换使用.%[Objective and Method] The present study is to screen fungicides which can effectively control the wheat powdery mildew disease,Blumeria graminis f.sp.tritici.[Method] 6 kinds of fungicides were tested by spraying medicine onto the diseased plants in the laboratory and field experiments.[Result]Results showed that treatments of 25% propiconazole with the rate of 112.5 g a.i/hm2,25% triadimefon with the rate of 135 g a.i/hm2,40% flusilazole with the rate of 48 g a.i/hm2 provided effective control both in laboratory and in field experiments,and the control efficacy on the tenth day after spraying were 82.02%,81.84%,69.25%,74.02%,67.99% and 67.24% respectively.Treatments of 25% ethirimol with the rate of 187.5 g a.i/hm2,25% hexaconazole with the rate of 18.75 g a.i/hm2,and 10% ZJ0712 with the rate

  5. Marker Assisted Transfer of Two Powdery Mildew Resistance Genes PmTb7A.1 and PmTb7A.2 from Triticum boeoticum (Boiss. to Triticum aestivum (L..

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    Ahmed Fawzy Abdelnaby Elkot

    Full Text Available Powdery mildew (PM, caused by Blumeria graminis f. sp. tritici, is one of the important wheat diseases, worldwide. Two PM resistance genes, designated as PmTb7A.1 and PmTb7A.2, were identified in T. boeoticum acc. pau5088 and mapped on chromosome 7AL approximately 48cM apart. Two resistance gene analogue (RGA-STS markers Ta7AL-4556232 and 7AL-4426363 were identified to be linked to the PmTb7A.1 and PmTb7A.2, at a distance of 0.6cM and 6.0cM, respectively. In the present study, following marker assisted selection (MAS, the two genes were transferred to T. aestivum using T. durum as bridging species. As many as 12,317 florets of F1 of the cross T. durum /T. boeoticum were pollinated with T. aestivum lines PBW343-IL and PBW621 to produce 61 and 65 seeds, respectively, of three-way F1. The resulting F1s of the cross T. durum/T. boeoticum//T. aestivum were screened with marker flanking both the PM resistance genes PmTb7A.1 and PmTb7A.2 (foreground selection and the selected plants were backcrossed to generate BC1F1. Marker assisted selection was carried both in BC1F1 and the BC2F1 generations. Introgression of alien chromatin in BC2F1 plants varied from 15.4-62.9 percent. Out of more than 110 BC2F1 plants showing introgression for markers linked to the two PM resistance genes, 40 agronomically desirable plants were selected for background selection for the carrier chromosome to identify the plants with minimum of the alien introgression. Cytological analysis showed that most plants have chromosome number ranging from 40-42. The BC2F2 plants homozygous for the two genes have been identified. These will be crossed to generate lines combining both the PM resistance genes but with minimal of the alien introgression. The PM resistance gene PmTb7A.1 maps in a region very close to Sr22, a stem rust resistance gene effective against the race Ug99. Analysis of selected plants with markers linked to Sr22 showed introgression of Sr22 from T. boeoticum in

  6. Eficiência e persistência de fungicidas no controle do oídio do trigo via tratamento de sementes Efficiency and persistence of fungicides in the control of powdery mildew of wheat through seed treatment

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    Erlei Melo Reis

    2008-12-01

    Full Text Available O oídio do trigo, causado por Blumeria graminis f.sp. tritici, ocorre com alta freqüência e intensidade em cultivares suscetíveis, na região Sul do Brasil. Em experimento conduzido em casa-de-vegetação, avaliou-se a eficiência e o período de proteção dos fungicidas difenoconazole (15 SC 100, 200 e 300 mL, flutriafol (12,5 SC 200, 300 e 400 mL triadimenol (15 SC 200, 300 e 400 mL e triticonazole (20 SC 135, 270 e 400 mL/ 100 kg de sementes, em três doses da formulação comercial, aplicados via tratamento de semente para o controle do agente causal do oídio. Sementes de trigo, cultivar BR 23, suscetível à doença, foram tratadas com os fungicidas e semeadas em vasos plásticos, contendo como substrato uma mistura de solo, areia e vermiculita. Vasos contendo plantas de trigo, contendo sinais do fungo, foram colocados entre os tratamentos para servir como fonte de inóculo primário. As avaliações foram realizadas diariamente, no afilho principal, desde o surgimento dos primeiros sinais. Utilizou-se como critério de quantificação da doença a incidência de folhas infectadas, até que a planta estivesse com a quarta folha totalmente expandida. Curvas ajustadas segundo o modelo logístico foram obtidas para cada fungicida em suas três doses. O período de proteção conferido pelos fungicidas foi menor para o produto difenoconazole, aumentando o período com o flutriafol e, posteriormente, com o triticonazole. O maior período de proteção foi obtido com o fungicida triadimenol.Wheat powdery mildew has been frequently detected in high intensities in wheat fields seeded with susceptible cultivars in southern Brazil. In experiment conducted in greenhouse the persistence of the fungicides difenoconazol, flutriafol, triadimenol, and triticonazol were assessed at three rates of commercial formulation, applied as seed treatment to control powdery mildew. Wheat seeds of cultivar BR 23, susceptible to powdery mildew, were treated with

  7. Inheritances of Resistance to Powdery Mildew and Stripe Rust in Cryptic Alien Introgression from Thinopyrum intermedium%小偃麦渐渗系对白粉病和条锈病抗性的遗传分析

    Institute of Scientific and Technical Information of China (English)

    詹海仙; 李光蓉; 张晓军; 李欣; 畅志坚

    2012-01-01

    CH5382 is a stable cryptic alien introgression carrying resistance genes of Thinopyrum intermedium. It was highly resistant to both powdery mildew and stripe rust disease. To determine the resistance inheritances in it, CH5382 was crossed with three susceptible cultivars (line ). The adult tests of F1 , F2 and F3 progenies from these crosses and their parents were inoculated with Egt isolate E09 in Taiyuan greenhouse and with mixed Pst isolates including CYR32 at Sichuan disease nursery Respectively. It was consistent to both powdery mildew (IT0) and stripe rust (IT 0; ) for F, plants and their resistant parent CH5382 indicating complete dominance of the two resistances in these crosses. Powdery mildew resistant and susceptible segregation ratios satisfactorily fit 3R: 1S in the F2 populations and segregation ratios for stripe rust reaction of F2 progenies from these crosses suit 3R: 1S. The F2.3 lines displayed a segregation ratio of 1 (all R): 2 segregating: 1 (all S) ,demonstrating that the powdery mildew resistance and stripe rust resistance in CH5382 were conferred by a single dominant gene separately.%CH5382是一个携带中间偃麦草抗性基因的隐形异源渐渗系,它兼抗白粉病和条锈病.为明确其抗性的遗传规律,用高感品种绵阳11、台长29和SY95-71杂交,将其F1、F2、F3家系及其亲本分别在太原温室(用白粉病E09菌系接种)和四川成都电子科技大学农场(用条锈病菌CYR32接种)进行了抗性基因的遗传分析.结果表明,F1对2种病害的抗性分别为免疫(0级),近免疫(0;级);F2分离群体中,白粉病抗感分离比例符合3R:1S;条锈病的抗感分离比例也符合3R:1S;F3家系的抗感分离比例均符合1R:2Seg:1S的理论比例.说明小偃麦渐渗系CH5382对白粉病和条锈病的抗性均受1对显性基因控制.

  8. Efeito de tipos de leite sobre oídio em abóbora plantadas a campo Effect of types of cow milk on the powdery mildew control of pumpkin under field conditions

    Directory of Open Access Journals (Sweden)

    Mariana Zatarim

    2005-06-01

    Full Text Available O trabalho foi realizado a campo para avaliar a eficiência de diversos tipos de leite de vaca sobre o oídio da abóbora cultivar Piramoita, causado por Sphaerotheca fuliginea. Utilizou-se o delineamento experimental de blocos ao acaso com seis tratamentos, cinco repetições e cinco plantas por parcela. Os tratamentos foram: leite cru, leite pasteurizado do tipo C, leite integral do tipo longa vida, leite pasteurizado tipo C + Yakult®, leite integral do tipo longa vida + Yakult® e água como controle. Os melhores resultados no controle da doença foram obtidos com leite de vaca cru, com leite do tipo C e leite do tipo C + Yakult®. Concluiu-se que leite é uma alternativa viável no controle do oídio, mesmo após o início da infecção, no campo. Sua utilização na forma de leite cru mais eficiente e na forma de longa vida o menos eficiente.In the present work we evaluated, under field conditions, the efficiency of several types of cow milk on the control of powdery mildew of pumpkin cv. Piramoita, caused by Sphaerotheca fuliginea. The experimental design consisted of randomized blocks with six treatments, five replications and five plants per plot. The treatments were: raw cow milk, pasteurized type C milk, integral long life milk and the association of the last two with Yakult® and a control with water. Milk is a viable alternative to control powdery mildew, even after infections have started under field conditions. Raw cow milk, type C milk and type C + Yakult® were the most efficient and integral long life was the least efficient.

  9. Research on Control Effects of Insecticidal Composition Picoxystrobin and Imidacloprid on Cucumber Powdery Mildew and Aphids%啶氧菌酯和吡虫啉高效杀菌杀虫组合物对黄瓜白粉病及蚜虫的防治效果研究

    Institute of Scientific and Technical Information of China (English)

    朱爽

    2013-01-01

    Control effects of insecticidal composition picoxystrobin and imidacloprid on cucumber powdery mildew and aphids were studied.The results showed that 40%imidacloprid picoxystrobin SC had the best control effect on cucumber powdery mildew and aphids ,control effects achieved 85.98%,84.89%,respectively.%进行啶氧菌酯和吡虫啉高效杀菌杀虫组合物对黄瓜白粉病及蚜虫的防治效果研究,结果表明:40%啶氧菌酯·吡虫啉悬浮剂对黄瓜白粉病及黄瓜蚜虫的防治效果最好,分别达85.98%、84.89%。

  10. Reaction of families and lines of melon to powdery mildew Reação de famílias e linhagens de melão ao oídio

    Directory of Open Access Journals (Sweden)

    Rui Sales Júnior

    2011-09-01

    Full Text Available Powdery mildew, caused by Podosphaera xanthii, is an important disease of melon in the Brazilian Northeast. The objective of this work was to evaluate the reaction of families, lines and cultivars of melon to P. xanthii. Two experiments in simple lattice were carried out under field conditions in the municipalities of Mossoró and Baraúna to evaluate 144 families. In a greenhouse, an experiment was carried out in a completely randomized design to evaluate 19 lines and the cultivars Yellow Queen, Chilton and Hy Mark. Disease was assessed by a severity scale. There was genetic variability among families. The families 4, 5, 11, 14, 18, 23, 33, 42, 101, 112 and 140 were identified in both sites as resistant. The lines LOF-027, LOF-105, LPS-124, MEL-008 and cultivar Chilton showed resistance to race 1 of the fungus.O oídio, causado por Podosphaera xanthii, é uma importante doença do melão no Nordeste brasileiro. O objetivo do presente trabalho foi avaliar a reação de famílias, linhagens e cultivares de melão a P. xanthii. Foram conduzidos, em condições de campo, nos municípios de Mossoró e Baraúna, experimentos em látice simples para avaliar 144 famílias. Em casa de vegetação, foi conduzido um experimento em delineamento inteiramente casualizado para avaliar 19 linhagens e as cultivares Yellow Queen, Chilton e Hy Mark. A severidade da doença foi avaliada mediante uma escala de notas. Houve variabilidade genética entre as famílias. Foram identificadas como resistentes, em ambos os locais, as famílias 4, 5, 11, 14, 18, 23, 33, 42, 101, 112 e 140. As linhagens LOF-027, LOF-105, LPS-124, MEL-008 e a cultivar Chilton mostraram resistência à raça 1 do fungo.

  11. Alternativas para el control de la cenicilla (Oidium sp. en pepino (Cucumis sativus L. Alternatives for the control of powdery mildew (Oidium sp. in cucumbers (Cucumis sativus L.

    Directory of Open Access Journals (Sweden)

    Moisés Gilberto Yáñez Juárez

    2012-04-01

    Full Text Available Esta investigación se realizó para conocer el efecto de sales de fosforo y potasio en el desarrollo y control de la cenicilla (Oidium sp. en pepino. Plantas de pepino var. Poinset 76 con signos de la enfermedad fueron asperjadas con soluciones de bicarbonato de potasio, bicarbonato de sodio, fosfato monopotásico, nitrato de potasio, cloruro de potasio y fosfito de potasio. La aplicación de sales no presentó efectos significativos (p≤ 0.05 en la altura y número de hojas en las plantas evaluadas. Con fosfito de potasio la incidencia de la enfermedad varió entre el 27.9 y 32.4%, con bicarbonato de potasio entre 19.9 y 29.5% y en el testigo la variación fue entre 44.1 y 47.4%. Veintiséis días después de la primera aplicación (dda las plantas tratadas con bicarbonato de potasio y fosfito de potasio mostraron 67.7 y 62.0% menor severidad que las testigo. Cuarenta y dos dda con bicarbonato de potasio y fosfito de potasio se logró 49.4 y 44.5% menos severidad que el testigo. Los resultados obtenidos mostraron que fosfito de potasio y bicarbonato de potasio a 5 y 4.7 g L, respectivamente, redujeron de manera significativa (p≤ 0.05 la incidencia y severidad de la enfermedad.This research was conducted to know the effect of phosphorous and potassium salts in the growth and control of powdery mildew (Oidium sp. in cucumbers. Cucumber plants of the variety Poinset 76 with signs of the disease were sprayed with potassium bicarbonate, sodium bicarbonate, monopotassium sulphate, potassium nitrate, potassium chloride and potassium phosphite solutions. The application of salts showed no significant effects (p≤ 0.05 on the height and number of leaves of plants evaluated. With potassium phosphite, the incidence of the disease varied between 27.9 and 32.4%; with potassium bicarbonate, it was between 19.9 and 29.5%, and in the control, variation went between 44.1 and 47.4%. Twenty-six days after the first application (dda, plants treated with

  12. Expression of WRKY and MYB genes during infection with powdery ...

    African Journals Online (AJOL)

    Moamar

    2012-06-12

    Jun 12, 2012 ... very likely encoding an important signaling component of leaf senescence and ... the two kinds of genes (WRKY and MYB) respond to the stress of powdery mildew ..... Signal perception and transduction in plant defense ...

  13. Combining ability in sweet pepper for resistance to powdery mildew Capacidade de combinação em pimentão para resistência a oídio

    Directory of Open Access Journals (Sweden)

    Cristina B Marchesan

    2009-06-01

    Full Text Available With the increase of the production of pepper in protected environment, pathogens began to cause serious damages to producers such as Leveillula taurica (Lév. Arn., fungus that causes powdery mildew. The systemic fungicides have not shown very satisfactory results. Thus, considering that protected cropping of pepper in Brazil is significant and growing, the incorporation of genes that confer resistance to powdery mildew is important for the maintenance of this cropping system. In this research, carried out in 2007 in Campinas, São Paulo State, Brazil, the agronomic performance and resistance to powdery mildew was determined by triple hybrids of sweet pepper through general and specific combining ability of their parents. For agronomic performance of the triple hybrid, it was evaluated the weight length and width average of the fruit, length and width ratio of the fruit and wall thickness. For severity of powdery mildew a scale of scores from 1 to 5 was used. For statistical and genetic analysis, it was adopted Griffing's method two, model I, adapted for partial diallel. The experimental design was completely randomized blocks, with 17 treatments, including ten experimental hybrids and seven parents, eight replications and four plants per plot. The additive effects were greater than the non-additive effects for all agronomic characters; 'P36-R' and 'Platero' were highlighted as good combiners; 'Quantum-R x HV-12', 'Rubia x HV-12' and 'P36-R x HV-12' presented the best specific combining ability; the mean square of the specific combining ability for the severity of the disease was significant indicating the importance of genes with dominant and epistatic effect; triple hybrids obtained by crosses with 'Quantum-R' and 'Rubia-R' had negative general combining ability and the best reactions to powdery mildew.Com o aumento do cultivo protegido de pimentão, patógenos como Leveillula taurica (Lév. Arn., fungo causador do oídio, passaram a causar s

  14. Powdery mildew of Allium species caused by Oidiopsis taurica in Brazil Oídio em espécies do gênero Allium, causado por Oidiopsis taurica, no Brasil

    Directory of Open Access Journals (Sweden)

    Ailton Reis

    2004-12-01

    Full Text Available Oidiopsis taurica Salmon (Syn. Oidiopsis sicula Scalia was identified as the causal agent of a powdery mildew disease occurring on distinct Allium species in Brazil. This disease was initially observed in plastic house and field-grown garlic (Allium sativum and leek (A. porrum accessions in Brasília (Federal District and in field-grown and greenhouse onion (A. cepa cultivars in Belém do São Francisco (Pernambuco State and Brasília, respectively. Typical symptoms consisted of chlorotic areas on the leaf surface corresponding to a fungal colony. These lesions turned to a brownish color with the progress of the disease. Fungi morphology was similar to that described for O. taurica. Endophytic mycelium emerging through estomata, light pale conidia were dimorphic (lanceolate primary conidia and somewhat cylindrical secondary conidia, fibrosin bodies were absent, conidia formed predominantly single (not in chains, and appressoria were non-lobed. Its sexual stage, Leveillula taurica (Lev. Arnaud, was not observed. Inoculations were performed with the O. taurica isolates from distinct Allium hosts. These isolates were also pathogenic to sweet pepper and tomato, indicating an apparent absence of host specialization. One bunching onion (A. fistulosum accessions was not infected by O. taurica suggesting that this species might carry useful resistance alleles to this pathogen. This is the first formal report of a powdery mildew disease on species of the genus Allium in Brazil. This disease might become important on these vegetable crops especially in hot and dry areas such as those in the Central and Northeast regions of Brazil.O fungo Oidiopsis taurica Salmon (= Oidiopsis sicula Scalia foi identificado como sendo o agente causal de uma nova doença do tipo oídio em alho (Allium sativum, alho porró (A. porrum e cebola (A. cepa no Brasil. Esta doença foi observada tanto em condições de casa de vegetação quanto a campo em Brasília e Pernambuco. O

  15. Identification of mildew resistance in wild and cultivated Central Asian grape germplasm

    OpenAIRE

    Riaz, Summaira; Boursiquot, Jean-Michel; Dangl, Gerald; Lacombe, Thierry; Laucou, Valerie; Tenscher, Alan C; Walker, M. Andrew

    2013-01-01

    Abstract Background Cultivated grapevines, Vitis vinifera subsp. sativa, evolved from their wild relative, V. vinifera subsp. sylvestris. They were domesticated in Central Asia in the absence of the powdery mildew fungus, Erysiphe necator, which is thought to have originated in North America. However, powdery mildew resistance has previously been discovered in two Central Asian cultivars and in Chinese Vitis species. ...

  16. Control Effect of Different Fungicides to Powdery Mildew of Jatropha curcas%不同药剂对麻疯树白粉病的防治效果研究

    Institute of Scientific and Technical Information of China (English)

    郑少华

    2014-01-01

    Four highly effective and lowly toxic fungicides (including 70% of methyl topsin wettable powder ,50% of daconil suspending agent ,5% of hexaconazole microemulsion and 15% of triadimefon wettable powder)were used in plot trials and the results show that all of them are effective to the control of powdery mildew and among them ,the best effective fungicides is 70% of methyl topsin with 800 times of water and the controlling effect reaches 88 .89%after spraying 3 times ,which had remarkable and lasting effect ,and the control effect was superior to others .The controlling effect of tow concentration chemicals can be strengthened obviously by increasing spraying times ,there-fore ,it is suggested that low concentration chemicals should be sprayed continuuously 2 ~ 3 times ,which can delay the resistance of powdery mildew to fungicides .%选用日曹-甲基托布津70%可湿性粉剂、百菌清50%悬浮剂、云大翠丽5%己唑醇微乳剂和粉锈宁15%可湿性粉剂等4种高效低毒的农药对麻疯树白粉病进行大田药效试验,结果表明:4种药剂对麻疯树白粉病均具有显著的防治效果,其中以日曹-甲基托布津70%可湿性粉剂稀释800倍液的防治效果最好,3次施药后防治效果达88.89%,对麻疯树白粉病的防治效果显著且稳定,优于其他药剂;喷洒次数的增加可明显提高低浓度杀菌剂的防治效果,因此生产上应尽量使用低浓度药剂连续喷洒2~3次,可延缓麻疯树白粉病抗药性的产生。

  17. Use of suppression subtractive hybridization to identify downy mildew genes expressed during infection of Arabidopsis thaliana.

    Science.gov (United States)

    Bittner-Eddy, Peter D; Allen, Rebecca L; Rehmany, Anne P; Birch, Paul; Beynon, Jim L

    2003-11-01

    SUMMARY Peronospora parasitica is an obligate biotrophic oomycete that causes downy mildew in Arabidopsis thaliana and Brassica species. Our goal is to identify P. parasitica (At) genes that are involved in pathogenicity. We used suppression subtractive hybridization (SSH) to generate cDNA libraries enriched for in planta-expressed parasite genes and up-regulated host genes. A total of 1345 clones were sequenced representing cDNA fragments from 25 putative P. parasitica (At) genes (Ppat 1-25) and 618 Arabidopsis genes. Analyses of expression patterns showed that 15 Ppats were expressed only in planta. Eleven Ppats encoded peptides with homology (BlastP values planta-expressed genes from P. parasitica (At) that complements other gene discovery approaches such as EST sequencing.

  18. 高抗白粉病小麦-山羊草新种质TA002的创制和遗传研究%Development and Genetic Analysis of a Novel Wheat-Aegilops Germplasm TA002 Resistant to Powdery Mildew

    Institute of Scientific and Technical Information of China (English)

    王玉海; 何方; 鲍印广; 明东风; 董磊; 韩庆典; 李莹莹; 王洪刚

    2016-01-01

    Objective] Powdery mildew is one of the most devastating diseases of wheat. It is widely accepted that the most economic, efficient and safest way to control powdery mildew is breeding and planting powdery mildew resistant cultivars.Aegilops ventricosa andAegilops cylindrica, which possess many favorable characters and good qualities such as resistance to diseases, tolerance to environmental stresses, are close-related relatives of wheat. The objective of this study was to develop novel powdery mildew resistant germplasm line via wide hybridization between common wheat andAegilops ventricosa and/orAegilops cylindrica for genetic improvement.[Method] Improved fuchsin squash and seed set examination were used to determine the cytogenetic stability and fertility of TA002. Acid polyacrylamide gel electrophoresis (A-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to analyze the subunit composition of gliadin, high and low molecular weight glutenin (HMW-GS and LMW-GS) respectively. Genomicin situ hybridization (GISH), multicolor genomicin situ hybridization (mc-GISH), multicolor fluorescencein situhybridization (mc-FISH) and molecular markers were employed to detect the genetic nature of TA002. Respective inoculation of powdery mildew isolates was performed to detect the reaction of TA002 to powdery mildew.[Result] TA002 (2n = 42) showed equivalent seed set to that of common wheat. Both TA002 and its hybrid F1 with common wheat Mingxian169 housed 21 bivalents in the pollen mother cells observed at metaphase I (PMCs MI) and took on chromosomal segregation of 21 to 21 in pollen mother cells examined at anaphase I (PMCs AI). Contrast to wheat parent Yannong15 highly susceptible to powdery mildew, TA002, similar to SDAU18 and its parentsAegilops ventricosa andAegilops cylindrica, was highly resistant to powdery mildew. Immunization and resistant-susceptible segregation of 3﹕1 was observed respectively in F1and F2 of the crosses

  19. Cashew Apple Damage of 60 Cashew Clones Caused by Powdery Mildew Disease in Mozambique%莫桑比克60个腰果品系果梨抗白粉病调查初报

    Institute of Scientific and Technical Information of China (English)

    梁李宏; 王金辉; 张中润; Americo Uaciquete; 黄海杰; 黄伟坚

    2012-01-01

    在莫桑比克楠普拉省调查了白粉病对60个腰果品系果梨的为害情况.结果显示,在相同的栽培条件下,不同腰果品系的果梨受白粉病为害程度差异很大.品系AZA17/79受白粉病的为害程度最低,为害率和为害指数分别仅为3.7%和0.91%,其次为H1、M96-2.3VM、AC34、4.2VM和Local 3,为害率在9.4% ~20.4%,为害指数在4.87%~10.28%.其余品系的果梨为害率和为害指数相对较高.根据本文的腰果品系对白粉病抗性的评价标准(果梨),对60个腰果品系的果梨抗白粉病进行了评价,结果表明:高抗品系有5个,分别为AZA17/79、H1、M96-2.3VM、AC34和4.2VM;抗性品系5个,分别为Local 3、B4、2.4PA、1.20VM和11.9PA;中抗品系3个,分别为CCM9-61、AC10/14和5.12PA;感病品系6个,为AC6、9.1NAS、7.1PA、1.12PA、12.8PA和12.9PA;其余41个品系均属于高感品系.说明莫桑比克推广种植的腰果品系的果梨对白粉病抗性普遍较差,容易遭受白粉病为害.%In Nampula Province of Mozambique, the cashew apple damage of 60 cashew clones caused by powdery mildew disease was investigated. The result indicated that, under the same condition, the cashew apple damage degree of different cashew clones was different. The cashew apple damage degree of AZA17/79 was the lowest. Its damage rate and damage index was 3.7% and 0.91 % respectively. The next were HI, M96-2.3VM, AC34, 4.2VM and Local 3. Their damage rates were between 9.4% and 20.4%, and their damage indexes were between 4.87% and 10.28%. The damage rates and damage indexes of other clones were higher relatively. According to the resistance evaluation criteria of cashew to powdery mildew disease in this paper, there were 5 high resistant clones, 5 resistant clones, 3 moderate resistant clones, 6 susceptible clones and 41 high susceptible clones in the 60 investigated cashew clones. The high resistant clones were AZA17/79, HI, M96 ?2.3VM, AC34 and 4.2VM. The resistant clones

  20. Vitis vinifera VvNPR1.1 is the functional ortholog of AtNPR1 and its overexpression in grapevine triggers constitutive activation of PR genes and enhanced resistance to powdery mildew.

    Science.gov (United States)

    Le Henanff, Gaëlle; Farine, Sibylle; Kieffer-Mazet, Flore; Miclot, Anne-Sophie; Heitz, Thierry; Mestre, Pere; Bertsch, Christophe; Chong, Julie

    2011-08-01

    Studying grapevine (Vitis vinifera) innate defense mechanisms is a prerequisite to the development of new protection strategies, based on the stimulation of plant signaling pathways to trigger pathogen resistance. Two transcriptional coactivators (VvNPR1.1 and VvNPR1.2) with similarity to Arabidopsis thaliana NPR1 (Non-Expressor of PR genes 1), a well-characterized and key signaling element of the salicylic acid (SA) pathway, were recently isolated in Vitis vinifera. In this study, functional characterization of VvNPR1.1 and VvNPR1.2, including complementation of the Arabidopsis npr1 mutant, revealed that VvNPR1.1 is a functional ortholog of AtNPR1, whereas VvNPR1.2 likely has a different function. Ectopic overexpression of VvNPR1.1 in the Arabidopsis npr1-2 mutant restored plant growth at a high SA concentration, Pathogenesis Related 1 (PR1) gene expression after treatment with SA or bacterial inoculation, and resistance to virulent Pseudomonas syringae pv. maculicola bacteria. Moreover, stable overexpression of VvNPR1.1-GFP in V. vinifera resulted in constitutive nuclear localization of the fusion protein and enhanced PR gene expression in uninfected plants. Furthermore, grapevine plants overexpressing VvNPR1.1-GFP exhibited an enhanced resistance to powdery mildew infection. This work highlights the importance of the conserved SA/NPR1 signaling pathway for resistance to biotrophic pathogens in V. vinifera.

  1. Reação de acessos de pimentão e pimentas ao oídio (Oidiopsis taurica Reaction of sweet and hot pepper accesses to powdery mildew (Oidiopsis taurica

    Directory of Open Access Journals (Sweden)

    Sally F. Blat

    2005-03-01

    Full Text Available O oídio causado pelo fungo Oidiopsis taurica é uma das principais doenças no gênero Capsicum spp. Seus danos podem causar desfolha de até 75% e perdas de até 40% em produção. Seu controle através de fungicidas tem se mostrado ineficaz, sendo a resistência genética a melhor alternativa. Poucas fontes de resistência já foram identificadas em Capsicum annuum. Neste trabalho avaliou-se os acessos da coleção de Capsicum spp. do banco de germoplasma da USP/ESALQ quanto às suas reações ao oídio e identificar novas fontes de resistência. O experimento foi conduzido em casa de vegetação em condições severas de ocorrência do patógeno. Durante a fase de frutificação foi feita a avaliação das reações, através de uma escala de notas, de 1 (resistente a 5 (altamente suscetível. Dos 156 acessos testados, 53 foram considerados resistentes, sendo representados por 5 acessos em C. annuum, 31 em C. baccatum e 17 em C. chinense. Dentre os acessos resistentes em C. annuum, a variedade dihaploide HV-12 mostrou-se como a mais resistente. Duas novas fontes de resistência se destacaram em C. annuum, #124 e Chilli. Esses acessos mostraram um mecanismo diferenciado de resistência, apresentando uma reação de hipersensibilidade ao patógeno. Os híbridos comerciais Reinger, Nathalie, Margarita, Magali R e Magda foram classificados como suscetíveis a altamente suscetíveis. Grande parte dos acessos resistentes de C. baccatum e C. chinense apresentaram desfolha em conseqüência do mecanismo de hipersensibilidade.Powdery mildew caused by Oidiopsis taurica is one of the major diseases of Capsicum spp., causing damage due to defoliation of up to 75% and yield losses of up to 40%. Disease control with fungicide is inefficient, genetic resistance being the best way of control. Few resistant sources have been identified in Capsicum annuum. Capsicum spp. collection accesses of USP/ESALQ germplasm bank were screened in their reaction and

  2. 遥感与气象数据结合预测小麦灌浆期白粉病%Wheat powdery mildew forecasting in filling stage based on remote sensing and meteorological data

    Institute of Scientific and Technical Information of China (English)

    马慧琴; 黄文江; 景元书

    2016-01-01

    利用多源数据对区域尺度上小麦白粉病的发生状况准确及时地预报能为农业服务和农业植保等部门提供重要信息,实现小麦白粉病的有效预防。研究利用一景2014年5月6日的landsat8遥感影像提取出植被指数、地表温度(land surface temperature,LST)和影像中各波段反射率特征,同时用2014年3月-5月份的站点逐日地面气象资料计算获得各气象特征,并经过GIS空间插值分析得到相应的空间气象特征。通过Relief算法和泊松相关系数相结合的方式进行遥感和气象特征的筛选,最终得出改进的简单比值指数(modified simple ratio index,MSR)、重归一化植被指数(re-normalized difference vegetation index,RDVI)、3月21日-4月20日总日照时数和4月11日-5月10日大于0.1 mm降雨日数。采用相关向量机(relevance vector machine,RVM)的方法分别用筛选出的遥感、气象数据特征及2种数据特征相结合的方式构建了河北省石家庄市藁城、晋州和赵县3地区小麦灌浆期白粉病的发生预测模型,并对3种不同数据模型进行了验证与评估。试验结果表明,遥感气象数据模型的总体精度达到84.2%,优于遥感数据模型的80.0%和气象数据模型的74.7%。进而得出,相比于单站点准确和空间不连续的气象数据和类型单一的遥感数据,遥感气象数据更适合于区域尺度范围内的作物病虫害发生发展状况的预测研究。%Powdery mildew is one of the main serious diseases for winter wheat. An accurate and timely forecasting of the wheat powdery mildew occurrence at the regional scale by using multi-source data can provide important information for crop protection decision making, and achieving effective prevention of wheat powdery mildew. In this study, the Landsat8 remote sensing image was used to extract the land surface temperature (LST), the vegetation indices which included

  3. 小麦新品系2-26中抗白粉病基因的遗传分析和RAPD标记%GENETIC ANALYSIS AND RAPD MARKERS OF POWDERY MILDEW RESISTANCE GENE IN WHEAT LINE 2-26

    Institute of Scientific and Technical Information of China (English)

    赵勤; 白罗; 傅体华

    2011-01-01

    Powdery mildew,caused by Blumeria Graminis f.sp.tritici,is one of the most important damaging diseases in many regions of the world.In present study,genetic analysis of resistance for powdery mildew in a stable wheat line 2-26,which was derived from the hybrid progeny between Triticum durum-Dasypyrum villosum amphiploid and common wheat,was carried out.The result indicated the powdery mildew resistance in line 2-26 is controlled by a single dominant gene and temporarily named Pm2-26.Molecular markers and bulked sergeant analysis were used to characterized the powdery mildew resistance gene.Two RAPD markers(SBSC2 and SBSI20) were found tightly linked to the resistance gene in line 2-26.These results provided a basis to further transfer into stable SCAR marker in future.In addition,the gene origin in line 2-26 and relationships with other resistance genes were also discussed in this paper.%由小麦白粉病菌引起的白粉病是世界上很多小麦种植区的主要病害之一。本研究对稳定抗白粉病品系2-26中的抗病基因采用常规遗传方法进行了分析。结果表明,2-26中存在一对显性抗白粉病基因,暂命名为Pm2-26。运用RAPD方法对白粉病抗感亲本和抗感池进行DNA多态性分析,获得2个紧密连锁的RAPD标记(SBSC2和SBSI20),为进一步转化为稳定可靠的SCAR标记提供了基础。

  4. Mid-term Prediction on Meteorological Factors for Wheat Powdery Mildew (Blumeria graminis) in Hebei Province Based on Fisher Criterion%基于Fisher判别准则的河北省小麦白粉病气象条件中期预报模型

    Institute of Scientific and Technical Information of China (English)

    司丽丽; 姚树然; 闫峰

    2013-01-01

    Correlation analysis between wheat powdery mildew occurrence data of 7 stations in Hebei province and meteorological data in corresponding period from 1983 to 2010 was made.It was confirmed that the average relative humidity during late March to middle April was the key factor for the epidemic disease.There was no significant difference between slight and serious areas in Hebei province by using of the T-test for the difference of disease occurrence.It is not necessary to establish different prediction models for different regions.Discriminant classifying models for wheat powdery mildew were established by using of Fisher criterion.The model accuracy reached 82.5%based on evaluation for the historical data,and the forecasting result in the year of 2010 displayed that the accuracy was 100%.In general,the forecasting accuracy of powdery mildew was raised by establishing the models,and these models provide a solid foundation for wheat powdery mildew forecasting and early control on wheat.%将1983-2010年河北省麦区7个站点的白粉病发生程度与同期气象资料进行相关分析,初步明确了3月下旬-4月中旬平均相对湿度是影响病害流行的关键气象因子;t检验结果显示,河北省白粉病轻、重分布区的差异不显著,表明不必分区建立预测函数;通过Fisher判别准则,构建了白粉病发生程度的判别分级模型,其历史拟合率达到82.5%,2010年的试报准确率达到100%,表明模型预报效果较好.该模型的建立提高了对小麦白粉病预测的准确性,为小麦白粉病的早期防治提供了依据.

  5. Genetic Analysis and Gene Deduction of Powdery Mildew Resistance in T. durum-Ae. squarrosa Amphidiploids%硬粒小麦-粗山羊双二倍体白粉病抗性的遗传分析与基因推导

    Institute of Scientific and Technical Information of China (English)

    胡英考; 辛志勇; 陈孝; 张增艳; 段霞瑜

    2001-01-01

    对99份硬粒小麦-粗山羊双二倍体用北京地区流行的5号白粉菌生理小种进行了白粉病抗性鉴定,筛选出11个苗期抗病的双二倍体材料和2个全生育期抗病的材料M53和M81。对M53和M81及其硬粒小麦和粗山羊草亲本进行的抗白粉病鉴定结果表明,其抗性来源于粗山羊草。与M53和M81具有相同硬粒小麦亲本、不同粗山羊草亲本双二倍体的抗性结果也表明抗性基因来源于粗山羊草。对M53和M81的抗性遗传分析表明,它们均携带1个单显性抗病基因。用14个白粉菌生理小种对已知抗病基因品系与M53和M81两份待测材料进行接种鉴定,结果表明,M53和M81与已知基因的抗菌谱均不相同,M53与M81的抗菌谱也不相同,说明M53和M81各自分别携带1个新的显性抗白粉病基因。%Eleven seedlings with resistance and two amphidiploids with disease resistanceatalldevelopmental stagewerescreened by using No.15 isolate of E. graminis f. sp. tritici to inoculate 99 T. durum-Ae. squarrosa amphidiploids. The two amphidiploids with disease resistance at all developmental stage, M53 and M81, and their Ae. squarrosa parents were resistant to No.15 isolate of powdery mildew payhogen, but their T. durum parents were susceptible. Therefore, the powdery mildewresistance of M53 and M81 were derived from Ae. squarrosa. Amphidiploid M74, which had the same durum parent as M53 but different Ae. squrrosa parent, was susceptible to No.15 isolate in adult stage. M29 and M35, which had the same durum parent as M81 but different Ae. squarrosa parent were susceptible in all stage. These results were also proved that the powdery mildew resistance genes were derived from Ae. sqarrosa. Genetic analysis showed that powdery mildew resistance gene in M53 or M81 was a single dominant gene. A series of lines with known powdery mildew resistance genes and two unknown lines were used to test response patterns with 14 differential isolates of

  6. Eficácia de extratos de nim para o controle do oídio do feijoeiro Effectiveness of neem extracts in controlling the powdery mildew of bean plant

    Directory of Open Access Journals (Sweden)

    Solange Monteiro de Toledo Piza Gomes Carneiro

    2007-03-01

    Full Text Available O nim, Azadirachta indica, vem sendo estudado nos últimos anos para o controle de fitopatógenos. O objetivo deste trabalho foi avaliar o efeito do óleo, do extrato de sementes e do extrato de folhas de nim no controle do oídio do feijoeiro, em casa de vegetação. Uma formulação comercial de óleo emulsionável de nim foi testada em concentrações entre 0,25 e 2,0%, em aplicações antes ou após o surgimento dos sintomas da doença. O extrato de sementes foi produzido em laboratório por meio da trituração das sementes em água destilada, sendo pulverizado 48 horas antes ou 24 horas após a inoculação do patógeno. Avaliou-se, após o surgimento dos sintomas, a eficiência de uma formulação comercial de extrato de folhas, nas concentrações de 0,25 e 0,5%. Verificou-se que o óleo de nim foi eficiente para o controle da doença quando aplicado antes ou depois do surgimento dos sintomas. O extrato de sementes controlou a doença nas três concentrações testadas. Por outro lado, o extrato de folhas não foi eficiente no controle do oídio do feijoeiro.The neem, Azadirachta indica, has been studied in the last years for the use in controlling plant pathogens. The objective of this work was to evaluate the effect of the neem oil, seed kernel extract and leaf extract on the control of the powdery mildew of the bean plant under green house conditions. The emulsified neem oil was tested for concentrations between 0.25 and 2.0% and sprayed before or after the appearance of the symptoms of the disease. The seed kernel extract was produced under laboratory conditions by grinding the kernels in distilled water, which was sprayed 48 hours before or 24 hours after the inoculation of the pathogen. It was also evaluated the efficiency of a commercial leaf extract at the concentrations of 0.25 and 0.5% which was sprayed after the appearance of the symptoms. The results of this work showed that the neem oil was efficient in the control of the

  7. Study on the Technique of Controlling Powdery Mildew of Cucumber with Amistar%阿米西达防治黄瓜白粉病的技术研究

    Institute of Scientific and Technical Information of China (English)

    谢标洪; 朱文达; 华旭明; 曾传龙; 何益民

    2011-01-01

    [ Objective ] The purpose was to study the control technique of powdery mildew of cucumber. [ Method ] The sensitivity of Sphaerotheca fuliginea in melon to Amistar was studied by young plant spraying, fungicide-wetted leaf disc floating, leaf disc floating, leaf disc fungicide-wetting and sponge mat-leaf disc floating methods. [ Result] The EC50 of young plant spraying, fungicide-wetted leaf disc floating, leaf disc floating, leaf disc fungicide-wetting and sponge mat-leaf disc floating methods were 0. 020 00, 0. 004 67, 0.007 56, 0.070 90 and 0. 167 50 μg/ml resp. , indicating that fungicide-wetted leaf disc floating method was most sensitive and leaf disc floating method was secondary. The EC50 of 3 repetitions of leaf disc floating method were 0.007 75, 0.007 56 and 0. 007 80 μg/ml resp. , indicating that the repeatability of leaf disc floating method was best. The determination results of leaf disc floating method showed that the toxicity of Amistar to S. fuliginea in melon was stronger than that of myclobutanil. The control effects of 90 and 120 μg/ml 25% Amistar on powdery mildew of cucumber were significantly superior to that of control fungicide 30 μg/ml 17% myclobutanil. [ Conclusion ] Amistar could be used as efficient fungicide to control S. fuliginea in melon and it could be used as substitute for other fungicides, such as myclobutanil.%[目的]研究黄瓜白粉病的防治技术.[方法]采用小株喷雾法、叶盘沾药漂浮法、叶盘漂浮法、叶盘沾药法和海绵垫叶盘漂浮法研究了瓜类白粉病菌对阿米西达的敏感性,[结果]测得小株喷雾法、叶盘沾药漂浮法、叶盘漂浮法、叶盘沾药法和海绵垫叶盘漂浮法的EC50分别为0.020 00、0.004 67、0.007 56、0.07090和0.167 50μg/ml,表明叶盘沾药漂浮法最灵敏,叶盘漂浮法次之.叶盘漂浮法3次重复的EC50分别为0.007 75、0.007 56和0.007 80μg/ml, 说明叶盘漂浮法的重复性好.叶盘漂浮法测定结果表明,阿

  8. 几种药剂对压砂地甜瓜白粉病田间药效评价%Evaluation of Field Control Efficiency of Different Fungicides on Melon Powdery Mildew in Gravel-mulched Field

    Institute of Scientific and Technical Information of China (English)

    张怡; 徐彪

    2013-01-01

    [Aims] The purpose of this research was to screen out effective fungicides with good safety to provide evidences for scientific basis for the control of melon powdery mildew.[Methods] "DMRT" method was used to analyze variance and Duncan-style with new multiple range to test the significance of differences.[Results] The results showed that the efficacy of triadimefon 25% WP at 105 g a.i./ha,mancozeb 70% WP at 2100 g a.i./ha,kresoxim-methyl boscalid 30% SC at 202.5 g a.i./ha,kresoxim-methyl 50% DF at 150 g a.i./ha; flusilazole 40% EC at 48 g a.i./ha; sulfur 50% SC at 750 g a.i./ha were 40.01,74.76,81.99,75.43,43.58 and 72.55%,respectively,after 7 days of twice treatments.[Conclusions] Mancozeb 70% WP at 2100 g a.i./ha,kresoxim-methyl boscalid 30% SC at 202.5 g a.i./ha,kresoximmethyl 50% DF at 150 g a.i./ha and sulfur 50% SC at 750 g a.i./ha have better control effects,both safe to melon in the range of experiment fungicide dosages and no chemical injury was observed.All of them can be used to control melon powdery mildew and used alternatively.%[目的]筛选出对压砂地甜瓜白粉病防效较好的杀菌剂,为安全、高效防治甜瓜白粉病提供科学依据.[方法]采用“DMRT”法进行方差分析,并用邓肯氏新复极差法检验差异显著性.[结果]在第2次施药后7d,25%三唑酮WP 105 g a.i./hm2、70%代森锰锌WP 2100 g a.i./hm2、30%醚菌酯·啶酰菌胺SC 202.5 g a.i./hm2、50%醚菌酯DF 150 g a.i./hm2、40%氟硅唑EC 48 g a.i./hm2、50%硫磺SC 750 g a.i./hm2的防治效果分别40.01%、74.76%、81.99%、75.43%、43.58%和72.55%.[结论]70%代森锰锌WP 2100 g a.i./hm2、30%醚菌酯·啶酰菌胺SC 202.5 g a.i./hm2、50%醚菌酯DF 150 g a.i./hm2、50%硫磺SC 750 g a.i./hm2对甜瓜白粉病均防效良好,且对甜瓜安全无药害,可以用来防治甜瓜白粉病,交替使用.

  9. Identification of RAPD markers linked to powdery mildew resistance gene Pm23 in wheat%小麦抗白粉病基因Pm23的RAPD标记

    Institute of Scientific and Technical Information of China (English)

    张庆利; 刘艳华; 李涛; 高居荣; 王洪刚

    2003-01-01

    The Pm23 gene of wheat confers resistance to powdery mildew,which is one of the most serious diseases in many regions of the world.In this paper,bulked segregant analysis (BSA) was used to search for randomly amplified polymorphic DNA (RAPD) markers linked to Pm23 gene.320 decamer primers were screened,and were one RAPD marker (OPE051100) linked in coupling phase to Pm23 .Using the F2 mapping population from a cross of Pm23×Chancellor,Pm23 was shown to be closely linked to the marker OPE051100 at a genetic distance of 10.65±3.25 cM.This marker can be conveniently used for marker-assisted selection in wheat breeding programs for the identification or pyramiding of Pm23 with other resistance genes.%小麦抗白粉病基因Pm23对世界上很多麦区流行的白粉病表现高抗或免疫.本研究以Pm23和Chancellor为抗感亲本,用集群分离分析法对抗性基因Pm23进行了RAPD分析,从320个十碱基随机引物中筛选到一个与Pm23紧密连锁的相引相标记OPE051100. 对F2分离群体进行RAPD分析表明,该标记与Pm23基因之间的连锁距离为:10.65±3.25 cM.该标记可以有效用于小麦育种分子标记辅助选择中.

  10. 3种药剂防治奶油南瓜白粉病药效试验%Drug efficiency experiment of three fungicides on cream pumpkin powdery mildew

    Institute of Scientific and Technical Information of China (English)

    刘丽娥

    2012-01-01

    进行43%戊唑醇悬浮剂、0.5%大黄素甲醚水剂、75%肟菌.戊唑醇水分散粒剂3种药剂防治奶油南瓜白粉病的田间药效试验,结果表明:43%戊唑醇悬浮剂4 000倍液的防效较好,且持效期较长;其次为75%肟菌.戊唑醇水分散粒剂5 000倍液,具有戊唑醇与肟菌酯的综合作用机理、杀菌谱广的特点,持效期也较长;0.5%大黄素甲醚水剂250倍液的防效较低,但其为植物源杀菌剂,产品安全性较化学农药高,也具有应用推广前景。%The field drug-efficiency experiments of three kinds of fungicides(43% tebuconazole SC,0.5% physcion agent,75% trifloxystrobin· tebuconazole WG) on cream pumpkin powdery mildew disease were carried out.The results showed that 400-times diluent of 43% tebuconazole SC had a better control efficiency and longer effective period,followed by 5000-times diluent of 75% trifloxystrobin· tebuconazole WG,which had comprehensive action effects of trifloxystrobin and tebuconazole,a broad spectrum of disease control and longer effective period.However,250-times diluent of 0.5% physcion agent had lower control efficiency.But it also had potential application prospects,for it was botanical microbicides and was more safety than chemical fungicide.

  11. Effects of the Epichloёgansuensis endophyte on the disease resistance of drunken horse grass to powdery mildew%内生真菌对醉马草白粉病抗性的影响

    Institute of Scientific and Technical Information of China (English)

    柳莉; 郭长辉; 吕卉; 古丽君; 李春杰

    2015-01-01

    Previous studies have shown that endophytes can increase the resistance of drunken horse grass (Ach-natherum inebrians )to many stresses,such as insects,diseases,waterlogging,drought,salt,and heavy met-als.The aim of this study was to compare the resistance of endophyte-infected (E+ )and endophyte-free (E- ) drunken horse grass to powdery mildew (Blumeria graminis ).Forty pots of drunken horse grass (20 E+plants and 20 E- plants)were grown in a greenhouse.After 2 months,the natural infection rates,the percent-age of diseased leaves,and the disease indexes of powdery mildew in both E+ and E- plants were estimated and recorded.At the same time,the E+ and E- drunken horse grass plants were scored as healthy,slightly dis-eased,or severely diseased based on a disease index.Then,four replicates of E+ and E- plants were randomly selected to measure several physiological indexes;chlorophyll content,activities of superoxide dismutase (SOD)and peroxidase (POD),and the contents of malondialdehyde (MDA)and proline (Pro).Chlorophyll content was measured by acetone extraction,SOD and POD activities were evaluated using nitroblue tetrazoli-um and guaiacol assays,respectively,and MDA and Pro contents were determined using the sulfosalicylic acid and glucosinolate barbituric acid methods,respectively.The disease infection rate,the percentage of diseased leaves,and disease indexes of E- plants were 97%,86%,and 82.49,respectively,significantly higher (P <0.05)than their respective values in E+ plants (48%,60%,and 50.76).The chlorophyll and proline contents and SOD and POD activities were higher in E+ plants than in E- plants,regardless of whether the plants were slightly or severely infected.The MDA content was significantly (P <0.05 )lower in E+ plants than in E-plants.These results provide evidence that endophyte infection can increase the resistance of drunken horse grass to powdery mildew disease.%为研究内生真菌对醉马草白粉病抗性的影响,在温室条件下,

  12. Avaliação de danos de insetos e de severidade de oídio em genótipos de soja Evaluation of insect damage and powdery mildew severity in soybean genotypes

    Directory of Open Access Journals (Sweden)

    André Luiz Lourenção

    2005-01-01

    Full Text Available Avaliou-se o desempenho de 24 linhagens de soja do programa de melhoramento do Instituto Agronômico (IAC em experimentos de campo em relação ao ataque de insetos e à incidência de oídio. Três experimentos, um para cada ciclo (precoce, semiprecoce e médio foram instalados nas unidades experimentais de Assis (anos agrícolas 2001/2002 e 2002/2003 e de Ribeirão Preto (2001/2002. Para os três experimentos, o delineamento utilizado foi o de blocos ao acaso, com dez tratamentos e seis repetições. As injúrias foliares causadas por lagartas de Anticarsia gemmatalis Hübner foram estimadas visualmente, atribuindo-se uma porcentagem de desfolha à parcela inteira. Os danos de percevejos [Piezodorus guildinii (West. e Euschistus heros (F.] foram avaliados através da porcentagem de retenção foliar atribuída à parcela inteira e por meio da massa de grãos comerciáveis. A severidade de oídio (Microsphaera diffusa Cke. Pk. foi estimada mediante escala de notas de 1 a 5, de acordo com a intensidade dos sintomas. Considerando-se os resultados das duas localidades, entre o germoplasma de ciclo precoce destaca-se a linhagem IAC 98-4307, com baixa retenção foliar e maior produtividade em presença de percevejos. No grupo de ciclo semiprecoce, observa-se que na linhagem IAC 98-2814 não há retenção foliar, porém, maior produtividade, caracterizando-se como resistente a percevejos, embora seja o genótipo mais desfolhado por lagartas e com maiores sintomas de oídio. Entre os genótipos de ciclo médio, IAC 98-2856 tem produtividade superior em presença de altas ou baixas infestações de percevejos, indicando possuir resistência do tipo tolerância, embora apresente retenção foliar sob baixa pressão de percevejos.Performance of 24 soybean lines from the breeding program of Instituto Agronômico (IAC was evaluated under field conditions, as to attack of insects and incidence of powdery mildew. Three experiments, one for each maturity

  13. 小麦种质N9820抗白粉病的特异基因表达谱分析%Expression of special genes resistant to powdery mildew ( Blumeria graminis f.sp.tritici) in wheat germplasm N9820

    Institute of Scientific and Technical Information of China (English)

    吴金华; 马峙英; 张西平; 吉万全

    2012-01-01

    Wheat germplasm N9820, developed by our research group, is a resistant material to powdery mildew. In order to understand the resistant mechanism of wheat germplasm N9820 to powdery mildew infection, a suppression subtraction hybridization (SSH) cDNA library was constructed with cDNA from N9820 leaf inoculated with Blumeria graminis as the tester and cDNA from N9820 healthy leaf as the driver. A total of 122 positive clones were randomly chosen from the SSH-cDNA library. After screening of repeated and redundant sequences, 61 ESTs were acquired. Nucleic acid and protein homology search were performed using the BLAST (Basic Local Alignment Search Tool) program with the default settings at NCBI website (http:// www. ncbi. nlm. nih. gov). BlastX results in nr-protein database revealed that 35 ESTs were highly homologous with known proteins involved in signal transduction, metabolism, cell structure, energy metabolism, transport, protein synthesis and processing, and disease resistance. BlastNr results showed that 47 ESTs had high identities with known ESTs, and 14 ESTs matched none in the nr-database. Compared with BlastX and BlastNr analysis, 19 ESTs were both in the nucleic acid and protein databases including 5 for energy metabolism, 2 for transport, 3 for protein synthesis and processing, and 2 for disease resistance. The most frequent sequence was ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit.

  14. Major Quantitative Trait Loci and Putative Candidate Genes for Powdery Mildew Resistance and Fruit-Related Traits Revealed by an Intraspecific Genetic Map for Watermelon (Citrullus lanatus var. lanatus).

    Science.gov (United States)

    Kim, Kwang-Hwan; Hwang, Ji-Hyun; Han, Dong-Yeup; Park, Minkyu; Kim, Seungill; Choi, Doil; Kim, Yongjae; Lee, Gung Pyo; Kim, Sun-Tae; Park, Young-Hoon

    2015-01-01

    An intraspecific genetic map for watermelon was constructed using an F2 population derived from 'Arka Manik' × 'TS34' and transcript sequence variants and quantitative trait loci (QTL) for resistance to powdery mildew (PMR), seed size (SS), and fruit shape (FS) were analyzed. The map consists of 14 linkage groups (LGs) defined by 174 cleaved amplified polymorphic sequences (CAPS), 2 derived-cleaved amplified polymorphic sequence markers, 20 sequence-characterized amplified regions, and 8 expressed sequence tag-simple sequence repeat markers spanning 1,404.3 cM, with a mean marker interval of 6.9 cM and an average of 14.6 markers per LG. Genetic inheritance and QTL analyses indicated that each of the PMR, SS, and FS traits is controlled by an incompletely dominant effect of major QTLs designated as pmr2.1, ss2.1, and fsi3.1, respectively. The pmr2.1, detected on chromosome 2 (Chr02), explained 80.0% of the phenotypic variation (LOD = 30.76). This QTL was flanked by two CAPS markers, wsb2-24 (4.00 cM) and wsb2-39 (13.97 cM). The ss2.1, located close to pmr2.1 and CAPS marker wsb2-13 (1.00 cM) on Chr02, explained 92.3% of the phenotypic variation (LOD = 68.78). The fsi3.1, detected on Chr03, explained 79.7% of the phenotypic variation (LOD = 31.37) and was flanked by two CAPS, wsb3-24 (1.91 cM) and wsb3-9 (7.00 cM). Candidate gene-based CAPS markers were developed from the disease resistance and fruit shape gene homologs located on Chr.02 and Chr03 and were mapped on the intraspecific map. Colocalization of these markers with the major QTLs indicated that watermelon orthologs of a nucleotide-binding site-leucine-rich repeat class gene containing an RPW8 domain and a member of SUN containing the IQ67 domain are candidate genes for pmr2.1 and fsi3.1, respectively. The results presented herein provide useful information for marker-assisted breeding and gene cloning for PMR and fruit-related traits.

  15. 氯化胆碱诱导黄瓜抗白粉病机理研究%Studies on Cucumber Resistance Mechanism to Powdery Mildew Induced by Choline Chloride

    Institute of Scientific and Technical Information of China (English)

    陈夕军; 沈世炜; 陈银凤; 张青; 张家豪; 张孝然; 黄奔立

    2013-01-01

    Choline chloride is a new growth regulator. When the cucumber seedlings were treated with 10 mmol·L-1 choline chloride,their plant height,root length,dry weight,fresh weight,and chlorophyll content were remarkably improved.Studies on induce resistance mechanism showed that the content or activity of β-1,3-glucanase,chitinase,hydroxyproline rich glycoproteins(HRGP)and malondialdehyde(MAD)of cucumber seedlings were significantly increased after being treated with choline chloride.The conidiospores of Sphaerotheca fuliginea were inoculated on the cucumber leaves treated with choline chloride.The results showed that the germination rate of conidiospores was decline. The length of germ tubes was shorter and the number of new conidia strings was less than the contrast. Choline chloride treatment on cucumber plants can delay and alleviate the occurrence of powdery mildew.%氯化胆碱是一种新型广效的生长调节剂,以10 mmol·L-1氯化胆碱处理黄瓜幼苗可明显提高植株的株高、根长、鲜质量、干质量和叶绿素含量。诱导抗性机理研究表明:氯化胆碱处理后,黄瓜幼苗体内β-1,3-葡聚糖酶、几丁质酶活性及富含羟脯氨酸糖蛋白、丙二醛含量均明显上升。以白粉病菌分生孢子接种经氯化胆碱处理过的黄瓜叶片,结果显示分生孢子萌发率较低,芽管较短,且新产生的分生孢子串数量较少。用氯化胆碱处理黄瓜植株,可延迟和减轻黄瓜白粉病的发生。

  16. Screening for SSR markers linked to wheat powdery mildew resistance gene Pm2%小麦抗白粉病基因Pm2的SSR标记筛选

    Institute of Scientific and Technical Information of China (English)

    王黎明; 朱玉丽; 李兴锋; 王洪刚

    2011-01-01

    为筛选与小麦抗白粉病基因Pm2紧密连锁的分子标记,将感病品种Chancellor与Pm2的近等基因系杂交,获得F1、F2分离群体,采用分离群体分组法对Pm2进行了微卫星(microsatellite,又称simple sequence repeats,SSR)标记分析.结果表明,定位于小麦5D染色体上的71对SSR引物中有12对引物能在Pm2的近等基因系、Chancellor间稳定地揭示出多态性差异,7对引物Xcfd189、Xcfd29、Xcfd8、Xcfd102、Xcfd7、Xcfd57和Xgwm190分别能在抗病、感病池间和F2分离群体的抗病、感病单株间稳定地扩增出特异性产物.7对引物所扩增的特异谱带分别为:Xcfd189360、Xcfd29190、Xcfd8160、Xcfd102250、Xcfd7200、Xcfd57245和Xgwm190210,它们与Pm2基因间的遗传距离分别为0、1.5、2.3、5.4、10.2、31.5和54.3 cM,其中标记Xcfd189360与Pm2共分离,标记Xcfd29190、Xcfd8160和Xcfd102250与Pm2紧密连锁,可用于Pm2的标记辅助选择.%To detect molecular markers linked to wheat powdery mildew resistance gene Pni2, microsatel-lite (simple sequence repeats, SSR) markers and bulked segregant analysis (BSA) method were used in the F2 segregation population derived from the F, of between common wheat susceptible cultivar Chancellor and Pm2 near-isogonics line ( NIL). The polymorphisms were revealed by 12 from 71 pairs SSR primers originally assigned to chromosome 5D of wheat between NIL of Pm2 and Chancellor. The polymorphic bands were found by 7 of these 12 SSR primers between the resistant and susceptible DNA pools, and the resistant and susceptible plants of the F2 population, respectively. These specific DNA bands were designated as Xcfd 189360, Xcfd29190, Xcfd8160, XcfdlO22JO, Xcfd, Xcfd57245 and Xgwml90210, respectively. The genetic distance between these marks and Pm2 was 0, 1.5, 2. 3, 5.4, 10. 2, 31.5 and 54. 3 cM, respectively. On the genetic linkage map of Pm2, Xcfdl89360 was shown to co-segregate with the Pm2 gene, and markers Xcfd29190, Xcfd8l60 and Xcfdl02j50

  17. Barley leaf transcriptome and metabolite analysis reveals new aspects of compatibility and Piriformospora indica-mediated systemic induced resistance to powdery mildew.

    Science.gov (United States)

    Molitor, Alexandra; Zajic, Doreen; Voll, Lars M; Pons-K Hnemann, Jorn; Samans, Birgit; Kogel, Karl-Heinz; Waller, Frank

    2011-12-01

    Colonization of barley roots with the basidiomycete fungus Piriformospora indica (Sebacinales) induces systemic resistance against the biotrophic leaf pathogen Blumeria graminis f. sp. hordei (B. graminis). To identify genes involved in this mycorrhiza-induced systemic resistance, we compared the leaf transcriptome of P. indica-colonized and noncolonized barley plants 12, 24, and 96 h after challenge with a virulent race of B. graminis. The leaf pathogen induced specific gene sets (e.g., LRR receptor kinases and WRKY transcription factors) at 12 h postinoculation (hpi) (prepenetration phase) and vesicle-localized gene products 24 hpi (haustorium establishment). Metabolic analysis revealed a progressing shift of steady state contents of the intermediates glucose-1-phosphate, uridinediphosphate-glucose, and phosphoenolpyruvate 24 and 96 hpi, indicating that B. graminis shifts central carbohydrate metabolism in favor of sucrose biosynthesis. Both B. graminis and P. indica increased glutamine and alanine contents, whereas substrates for starch and nitrogen assimilation (adenosinediphosphate- glucose and oxoglutarate) decreased. In plants that were more B. graminis resistant due to P. indica root colonization, 22 transcripts, including those of pathogenesis-related genes and genes encoding heat-shock proteins, were differentially expressed ?twofold in leaves after B. graminis inoculation compared with non-mycorrhized plants. Detailed expression analysis revealed a faster induction after B. graminis inoculation between 8 and 16 hpi, suggesting that priming of these genes is an important mechanism of P. indica-induced systemic disease resistance.

  18. A Barley ROP GTPase ACTIVATING PROTEIN Associates with Microtubules and Regulates Entry of the Barley Powdery Mildew Fungus into Leaf Epidermal Cells[C][W

    Science.gov (United States)

    Hoefle, Caroline; Huesmann, Christina; Schultheiss, Holger; Börnke, Frederik; Hensel, Götz; Kumlehn, Jochen; Hückelhoven, Ralph

    2011-01-01

    Little is known about the function of host factors involved in disease susceptibility. The barley (Hordeum vulgare) ROP (RHO of plants) G-protein RACB is required for full susceptibility of the leaf epidermis to invasion by the biotrophic fungus Blumeria graminis f. sp hordei. Stable transgenic knockdown of RACB reduced the ability of barley to accommodate haustoria of B. graminis in intact epidermal leaf cells and to form hairs on the root epidermis, suggesting that RACB is a common element of root hair outgrowth and ingrowth of haustoria in leaf epidermal cells. We further identified a barley MICROTUBULE-ASSOCIATED ROP-GTPASE ACTIVATING PROTEIN (MAGAP1) interacting with RACB in yeast and in planta. Fluorescent MAGAP1 decorated cortical microtubules and was recruited by activated RACB to the cell periphery. Under fungal attack, MAGAP1-labeled microtubules built a polarized network at sites of successful defense. By contrast, microtubules loosened where the fungus succeeded in penetration. Genetic evidence suggests a function of MAGAP1 in limiting susceptibility to penetration by B. graminis. Additionally, MAGAP1 influenced the polar organization of cortical microtubules. These results add to our understanding of how intact plant cells accommodate fungal infection structures and suggest that RACB and MAGAP1 might be antagonistic players in cytoskeleton organization for fungal entry. PMID:21685259

  19. Efeito de lodo de esgoto sobre patógenos habitantes do solo e severidade de oídio da soja Effect of sewage sludge in soil-borne pathogens and powdery mildew severity in soybean

    Directory of Open Access Journals (Sweden)

    Fabio Fernando de Araújo

    2009-09-01

    ântulas de soja, nos três cultivos, foi inversamente proporcional à concentração do lodo de Franca, sendo totalmente inibida na concentração de 20%. Nos estudos com R. solani não foram observados efeitos da aplicação do lodo da ETE de Franca sobre o tombamento e a severidade. No primeiro cultivo a resposta ao tombamento foi quadrática para o lodo Barueri, sendo que ocorreu aumento nas concentrações de 1N e 2N, e redução na concentração 4N. No segundo cultivo ocorreu aumento nos índices de tombamento de plantas em relação ao primeiro, com resposta quadrática para o lodo Barueri, mas com ponto de inflexão mínimo na concentração de 1N, sendo que para a concentração 8N o tombamento foi semelhante à testemunha. A severidade da doença no colo das plantas manteve a mesma resposta quadrática para o lodo de Barueri nos dois cultivos, com ponto de máximo na dose 4N. Para M. phaseolina a incidência da doença foi inversamente proporcional à concentração do lodo de Franca. Dessa forma, os resultados não permitem conclusão sobre a indução de supressividade à R. solani e M. phaseolina.Sewage sludge, complying with environmental demands, has potential for use in agriculture. The incorporation of sewage sludge may changes the chemical, physical and biological soil properties, for being rich in macro and micronutrients and organic matter. These changes can provide benefits such as the increase in the availability of nutrients for plants, and the induction of suppressiveness to soilborne plant pathogens and resistance to foliar diseases. However, it may influence negatively the biological and chemical balance of the soil, due to the presence of contaminants. The objective of this work was to evaluate the effect of sewage sludge on the severity soybean (Glycine max powdery mildew (Erysiphe diffusa and on suppressiveness to Rhizoctonia solani and Macrophomina phaseolina The experiments used soil which received four successive applications of sewage sludge

  20. Influência do espaçamento e população de plantas sobre doenças de final de ciclo e oídio e caracteres agronômicos em soja = Influence of row spacing and plant population on late season disease severity, powdery mildew and agronomic characters in soybean

    Directory of Open Access Journals (Sweden)

    Jorge Luiz Knebel

    2006-07-01

    Full Text Available Este trabalho foi conduzido em Cascavel, Estado do Paraná, na safra de2004/2005, utilizando a cultivar de soja CD 202, para avaliar a influência do espaçamento e da população de plantas sobre a severidade de (DFC doenças de final de ciclo (Septoria glycines e Cercospora kikuchii e oídio da soja (Microsphaera diffusa e caracteres agronômicos da cultura. Os tratamentos foram 3 espaçamentos (22,5; 45,0 e 67,5 cm e 3 populações (200; 400; e 600 mil plantas ha-1. As DFC tiveram menor severidade no espaçamento reduzido e na população mais baixa, enquanto a ocorrência de oídio não se alterou. Em todos os espa��amentos, quanto maior a população de plantas, maior a altura final e, conseqüentemente, maior o acamamento de plantas. O número de legumes/planta foi superior no maior espaçamento e reduziu com o aumento da população; o número de grãos/planta diminuiu com o aumento da população; e a produtividade foi superior no menor espaçamento.This study was carried out in Cascavel, Paraná State, during the growing season 2004/2005, using soybean cultivar CD 202. The aim was to evaluate the influence of row-spacing and plant population on lateseason disease severity (Septoria glycines and Cercospora kikuchii, soybean powdery mildew (Microsphaera diffusa and agronomic characters of the culture. The treatments were three row spacing (22.5; 45.0 and 67.5 cm and three plant populations (200; 400; and 600 thousand plants ha-1. Late season disease had smaller severity in the reduced spacing and in the lowest population, while the powdery mildew occurrence did not modify with these factors. In all spacing, as larger the plants density, larger the plants height and consequently larger the plants fallen. The number pods per plant was higher with the largest spacing and it decreased with the population increase; the number of grains per plant decreased with the population increase; and the productivity was higher in the smallest spacing.

  1. Effects of Silicon Fertilizer in Different Application Ways on Powdery Mildew Control, Starch Content and Farinographical Properties of Wheat (Triticum aestivum L.)%硅肥施用方式对小麦白粉病防治效果及籽粒淀粉含量与粉质特性的影响

    Institute of Scientific and Technical Information of China (English)

    王东勇; 杨习文; 贺德先; 吴寅

    2014-01-01

    以西农979和周麦18为材料,在大田条件下研究了硅肥不同施用方式对小麦白粉病防控效果及籽粒淀粉含量和粉质特性的影响。结果表明,增施硅肥能显著降低白粉病感病植株的病情指数,提高抗病能力,尤其是底施硅肥+挑旗期喷施硅肥处理的防控效果为最佳,灌浆中后期效果最为明显。硅肥不同施用方式均能提高籽粒总淀粉和支链淀粉的含量,其中底施硅肥+挑旗期喷施硅肥处理增幅分别达到10.4%和24.7%,降低直链淀粉的含量;同时可延长面团形成时间和稳定时间,提高面粉吸水率,降低弱化度。%Field experiments were conducted to investigate the effects of silicon fertilizer in various appli-cation ways on prevention and control of wheat powdery mildew , grain starch content and farinographical prop-erties with the cultivars Xinong 979 and Zhoumai 18 as experimental materials .The results showed that the disease index was decreased and the disease resistance was increased significantly under the silicon fertilization treatments, especially the treatment of bottom fertilization +foliar application at flag stage;the control effect of powdery mildew at late grain -filling stage was the best .The silicon fertilization treatments could increase the contents of total starch and amylopectin , and water absorption of flour , prolong the time of dough development and stability , but decrease the amylose content and weakening degree .The contents of total starch and amyl-opectin increased by 10 .4%and 24 .7%respectively under the treatment of bottom fertilization +foliar appli-cation at flag stage .

  2. Ultracytochemical Localization and Effects of Calcium on Isoenzyme in the Leaves of Cucumis melo L.Under the Stress of Powdery Mildew%白粉病菌胁迫下甜瓜叶片中Ca2+的细胞化学定位及外源Ca2+对POD、CAT和SOD同功酶的影响

    Institute of Scientific and Technical Information of China (English)

    钟俐; 李冠

    2012-01-01

    [Objective] The aim of this experiment is to study the uhracytochemical localization of calcium in mesophyll cells of Cucumis melo L. before and after inoculating Podosphaera xanthii and the effects of exogenous calcium on three isoenzymes of defense enzymes which will be useful for further elucidating the process of calcium signal transduction and resistance mechanism to powdery mildew of melon. [Method] With the method of electron microscope and cytochemistry technology, a hydroponic experiment was carried out to explore the effects of different calcium treatments on isoenzymes of peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) in leaves of the melon seedlings under powdery mildew stress. [Result] The calcium in mesophyll cells of resistant variety 'MR-1' and in susceptible variety 'JS' gathered in cytoplasm and there were a remarkable increase of calcium level in cytoplasm and reduced greatly in vacuolate and intercellular space when inoculating P. xanthii for 2 d. The calcium localization in leaf cells of 'MR-1' trended to the status as before inoculating when the seedlings were treated for 6 d. However, larger calcium deposited and localized together in the cytoplasm of 'JS' and the structure of mesophyll cells were destroyed until to death and there were no recover of calcium from cytoplasm into vacuolate and intercellular space. Compared with the control, the application 6 mmol-L-1 CaCl2 in nutrient solution significantly alleviated the stress on the melon leaves system that the activities of SOD, POD and CAT isoenzymes were significantly improved, while application of 75 mmol-L-1 LaCl3 in nutrient solution significantly inhibited the three isoenzymes activities. [Conclusion] Calcium ditribution in leaf cells of C. melo L. changed greatly due to its resistance ability at the stress of powdery mildew. A lot of Ca2+was released from Ca2+pool (vacuoles) into cytoplasm, then was pumped return vacuoles in mesophyll cells of resistance variety 'MR

  3. ldentification and Control of Powdery Mildew,Boll Rot Disease,Fruit Blight, Blossom Blight,Phytoph-thora Rot,Alternaria Fruit Rot of Eggplant%茄子白粉病、红腐病、果实疫病、花腐病、绵疫病和交链孢果腐病的识别与防治

    Institute of Scientific and Technical Information of China (English)

    李继红

    2012-01-01

    Damage symptom and onset characteristics of powdery mildew,boll rot disease,fruit blight,blossom blight, phytophthora rot and alternaria fruit rot of eggplant were introduced. To control these diseases scientifically and effec-tively on the basis of correct identifica-tion was the best way of mitigation of damage and increasing income.The study provided theoretical basis for improving yield and quality of eggplant.%介绍了茄子白粉病、红腐病、果实疫病、花腐病、绵疫病和交链孢果腐病的危害症状及发病特点,提出在正确识别病害的基础上,做到科学、有效的防治,是减轻损失、增大收益的最佳途径。为提高茄子的产量和品质提供了一定的理论依据。

  4. Identification of Wheat-Aegilops Ovata Derivatives Using SSR Markers and Evaluation of Their Powdery Mildew Resistance%小麦-卵穗山羊草衍生后代的SSR分子标记鉴定和白粉病抗性评价

    Institute of Scientific and Technical Information of China (English)

    吴红坡; 王亚娟; 王长有; 吉万全

    2012-01-01

    Aegilops species carrying the U or/and M genomes represent a prominent source of useful genes for wheat breeding. We generated 19 wheat-Aegilops ovata derivatives through hybridization between common wheat and Aegilops ovata. Four hundred SSR (simple sequence repeat) markers were used to investigate the polymorphisms among parental lines, Chinese Spring, Shaanyou 225 and Aegilopsovata, of which 341 markers (85.25%) could amplify bands in Aegilopsovata, and 20 of them (5%) showed specific bands in Aegilopsovata, and were applied to investigate germplasm in- heritance of Aegilops ovata in wheat-Aegilops ovata derivatives. The results showed that 10 markers could amplify specific bands in the 19 derivatives, indicating that all these 19 derivatives inherited germplasms from Aegilops ovata and these 10 SSR markers could be used in further identification of next generations. We also conducted powdery mildew resistance evaluation on the 19 derivatives, and 16 of them are immune to powdery mildew like Aegilops ovata, one of their parents, but not like the other two parental lines, Chinese Spring and Shaanyou 225, which are highly susceptible to powdery mildew, indicating that the powdery mildew resistance in the 16 derivatives were explicitly inherited from Aegilops ovata.%山羊草属植物是普通小麦改良过程中重要的有益基因来源,小麦的许多抗病虫、抗逆基因都来源于山羊草属植物。本研究利用杂交和回交的方法,成功获得了19株小麦-卵穗山羊草衍生后代,实验选取均匀分布于小麦各条染色体的SSR标记400个,对三个亲本(中国春、卵穗山羊草和陕优225)以及19株衍生后代进行分子标记特异性分析,结果表明,341个标记可以在卵穗山羊草中扩增出条带,说明SSR标记在山羊草中位点丰富;20个标记可以在卵穗山羊草中扩增出特异条带,说明在卵穗山羊草中有不同于另外两个亲本的特异SSR位点;将20个在卵穗山羊

  5. Efeitos de diferentes condições de irrigação e densidade de semeadura no microclima e na ocorrência de helmintosporiose de oídio em trigo Effects of different conditions of irrigation and crop density in microclimate and spot blotch and powdery mildew occurrence

    Directory of Open Access Journals (Sweden)

    Paulo Cesar Sentelhas

    1993-01-01

    Full Text Available Avaliou-se, em Campinas (SP, o efeito da irrigação por aspersão e da densidade de semeadura na temperatura média do ar e na duração do período de molhamento (DPM, e sua influência em helmintosporiose e oídio na cultura do trigo, em experimentos ao nível de campo durante os invernos de 1990 e 1991 respectivamente. Os resultados foram submetidos a análises estatísticas: de diferença de dados pareados (microclima e de intervalos de confiança (taxa de crescimento das moléstias. As áreas com maior densidade de plantas e irrigadas mostraram a seguinte tendência: as temperaturas médias foram mais baixas, 0,7°C, e a DPM, com maior duração, 45 minutos. Com relação às taxas de crescimento, notou-se que foram influenciadas positivamente pela irrigação e pela densidade de semeadura quando as condições macroclimáticas não eram amplamente favoráveis ao desenvolvimento dos patógenos.Field experiments (1990 and 1991 were carried out in Campinas, State of São Paulo, Brazil, during winter season, in order to study sprinkler irrigation and crop density effects on micrometeorological parameters (average air temperature and dew duration and to evaluate their influence in the occurrence of spot blotch and powdery mildew in wheat crop. The results obtained were submitted to statistical analysis: comparison of means of two independent sample analysis (microclimate and confidence interval analysis (infection rates. It was verified that in the most dense and irrigated plots the average air temperatures were lower (0.7°C and the dew durations (DPM were longer (45 minutes than in the other plots. The infection rates of diseases were influenced positively by irrigation and crop density when the macroclimatic conditions were not favorable to disease development.

  6. Naturally occurring broad-spectrum powdery mildw resistance in a central American tomato accession is caused by loss of Mlo function

    NARCIS (Netherlands)

    Bai, Y.; Pavan, S.N.C.; Zheng, Z.; Zappel, N.F.; Reinstadler, A.; Lotti, C.; Giovanni, de C.; Ricciardi, L.; Lindhout, P.; Visser, R.G.F.; Theres, K.; Panstruga, R.

    2008-01-01

    The resistant cherry tomato (Solanum lycopersicum var. cerasiforme) line LC-95, derived from an accession collected in Ecuador, harbors a natural allele (ol-2) that confers broad-spectrum and recessively inherited resistance to powdery mildew (Oidium neolycopersici). As both the genetic and phytopat

  7. Identification of molecular markers linked to the mildew resistance gene Pl-d in apple.

    Science.gov (United States)

    James, C M; Clarke, J B; Evans, K M

    2004-12-01

    Powdery mildew poses a serious problem for apple growers, and resistance to the disease is a major objective in breeding programmes for cultivar improvement. As selective pressure allows pathogens to overcome previously reliable resistances, there is a need for the introduction of novel resistance genes into new breeding lines. This investigation is concerned with the identification of the first set of molecular markers linked to the gene for mildew resistance, Pl-d, from the accession 'D12'. As no prior information on the map position or markers for Pl-d were available, a bulked-segregant approach was used to test 49 microsatellite primers, 176 amplified fragment length polymorphism (AFLP) primers and 80 random amplified polymorphic DNA (RAPD) primers in a progeny segregating for Pl-d resistance, 'Fiesta' (susceptible) x A871-14 ('Worcester Pearmain' x 'D12'). The segregations of the markers identified in the resistant and susceptible bulks were scored in the progeny, then the recombination fractions between Pl-d and the most tightly linked markers were calculated and a map prepared. Three AFLP, one RAPD and two microsatellite markers were identified. One AFLP was developed into a sequence-characterised amplified region marker, while the microsatellites CH03C02 and CH01D03 were flanking markers, 7 and 11 recombination units, respectively, from Pl-d. Two more distant microsatellites on the same linkage group, CH01D09 and CH01G12, confirmed the orientation of the markers on the linkage group. These microsatellites place Pl-d on the bottom of linkage group 12 in published apple maps, a region where a number of other disease resistance genes have been identified.

  8. 基于 rDNA-ITS 法鉴定的霉变烟叶真菌种类%Fungi Species in Mildew Tobacco Leaves Identified Based on rDNA-ITS

    Institute of Scientific and Technical Information of China (English)

    吴阔; 聂鑫; 朱法亮; 罗华元; 林昆; 李枝桦; 朱海滨; 饶智; 董石飞; 陈初; 侯占高

    2014-01-01

    为烟草仓储霉变的预防提供参考,利用稀释平板法和ITS序列鉴定红云红河集团仓库中霉变烟叶的真菌种类。结果表明:霉变烟叶的真菌主要为曲霉属和青霉属的烟曲霉、黑曲霉、灰绿曲霉、阿曲霉、黄曲霉、产黄青霉菌、桔青霉。%In order to provide a reference for preventing the occurrence of mildew in tobacco warehouse,the authors identified the fungal species in the warehouse of Hongyun-Honghe Tobacco Group by dilution-plate method and ITS sequence identification.Results:The local tobacco mildew occurred mainly from Aspergillus and Penicillium, including Aspergillus fumigatus , Aspergillus niger , Aspergillusglaucus, Aspergillus amstelodami , Aspergillus flavus , Penicillium chrysogenum and Penicillium citrinum .

  9. Immigration of the barley mildew pathogen into field plots of barley

    DEFF Research Database (Denmark)

    O'Hara, R.B.; Brown, J.K.M.

    1996-01-01

    Immigration of the barley powdery mildew pathogen (Erysiphe graminis f.sp. hordei) into field plots of the spring barley variety Tyra (carrying the resistance allele Mla1) was investigated. Spores were trapped from the top of the plot canopies, as well as from control plots of wheat with no barley...... nearby. Comparison of the frequencies of virulent and avirulent single-colony isolates showed that the amount of immigration, relative to the amount of inoculum being produced within the plot, reduced very rapidly, until it could not be detected in the middle of the growing season (mid-June)....

  10. Mutants of downy mildew resistance in Lactuca sativa (lettuce).

    Science.gov (United States)

    Okubara, P A; Anderson, P A; Ochoa, O E; Michelmore, R W

    1994-07-01

    As part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to Bremia lactucae, the casual fungus of downy mildew. Using a rapid and reliable screen, we identified 16 distinct mutants of Latuca sativa that have lost activity of one of four different downy mildew resistance genes (Dm). In all mutants, only a single Dm specificity was affected. Genetic analysis indicated that the lesions segregated as single, recessive mutations at the Dm loci. Dm3 was inactivated in nine of the mutants. One of five Dm 1 mutants was selected from a population of untreated seeds and therefore carried a spontaneous mutation. All other Dm1, Dm3, Dm5/8 and Dm7 mutants were derived from gamma- or fast neutron-irradiated seed. In two separate Dm 1 mutants and in each of the eight Dm3 mutants analyzed, at least one closely linked molecular marker was absent. Also, high molecular weight genomic DNA fragments that hybridized to a tightly linked molecular marker in wild type were either missing entirely or were truncated in two of the Dm3 mutants, providing additional evidence that deletions had occurred in these mutants. Absence of mutations at loci epistatic to the Dm genes suggested that such loci were either members of multigene families, were critical for plant survival, or encoded components of duplicated pathways for resistance; alternatively, the genes determining downy mildew resistance might be limited to the Dm loci.

  11. Detection of wheat powdery mildew by differentiating background factors using hyperspectral imaging

    Science.gov (United States)

    Accurate assessment of crop disease severities is the key for precision application of pesticides to prevent disease infestation. In-situ hyperspectral imaging technology can provide high-resolution imagery with spectra for rapid identification of crop disease and determining disease infestation pat...

  12. Scanning ultrastructural ontogeny of cleistothecia in the powdery mildew Microsphaera alphitoides

    Directory of Open Access Journals (Sweden)

    Katarzyna Turnau

    2014-08-01

    Full Text Available Morphogenesis of cleistothecia in Microsphaera alphitoides Griff. et Maubl. (Erysiphales, Ascomycetes on naturally infected leaf of oak was investigated with the scanning electron microscope. All phases of the life cycle of this specks have been described. Some comparisons between methods of preparation of the material have been made.

  13. Interaction of basal foliage removal and late season fungicide applications in management of Hop powdery mildew

    Science.gov (United States)

    Experiments were conducted over three years to evaluate whether fungicide applications could be ceased after the most susceptible stages of cone development (late July) without unduly affecting crop yield and quality when disease pressure was moderated with varying levels of basal foliage removal. I...

  14. Reactive oxygen intermediates in plant-microbe interactions: who is who in powdery mildew resistance?

    Science.gov (United States)

    Hückelhoven, Ralph; Kogel, Karl-Heinz

    2003-04-01

    Reactive oxygen intermediates (ROIs) such as hydrogen peroxide (H(2)O(2)) and the superoxide anion radical (O*(2)(-)) accumulate in many plants during attack by microbial pathogens. Despite a huge number of studies, the complete picture of the role of ROIs in the host-pathogen interaction is not yet fully understood. This situation is reflected by the controversially discussed question as to whether ROIs are key factors in the establishment and maintenance of either host cell inaccessibility or accessibility for fungal pathogens. On the one hand, ROIs have been implicated in signal transduction as well as in the execution of defence reactions such as cell wall strengthening and a rapid host cell death (hypersensitive reaction). On the other hand, ROIs accumulate in compatible interactions, and there are reports suggesting a function of ROIs in restricting the spread of leaf lesions and thus in suppressing cell death. Moreover, in situ analyses have demonstrated that different ROIs may trigger opposite effects in plants depending on their spatiotemporal distribution and subcellular concentrations. This demonstrates the need to determine the particular role of individual ROIs in distinct stages of pathogen development. The well-studied interaction of cereals with fungi from the genus Blumeria is an excellent model system in which signal transduction and defence reactions can be further elucidated in planta. This review article gives a synopsis of the role of ROI accumulation, with particular emphasis on the pathosystem Hordeum vulgare L.- Blumeria graminis.

  15. Uncinula necator (Schow Burr., the Causal Agent of Grape Powdery Mildew: Infection Potential and Microclimate

    Directory of Open Access Journals (Sweden)

    Zoran Miladinović

    2007-01-01

    Full Text Available Microclimate in Podgorica vineyards and its effect on the formation, maturing and rupturing of cleistothecia, and disease outbreak, was studied. An analysis of collected data on minimum and maximum temperatures and precipitation over the periods November-April (2001/2002, 2002/2003 and 2003/2004 and April-July (2002, 2003 and 2004 and their comparison with the average values over a 50-year period, indicate that neither temperature nor precipitation act as a limiting factor for disease outbreak and development in Podgorica vineyards. Over the trial period, conditions were favourable for the formation and maturing of cleistothecia between November and April. Asum of 1100ºC mean daily temperature was reached by mid-March.From bud burst to end of vine flowering, the conditions were again nearly optimal both for ascospore release from cleistothecia and primary infection, and for secondary infection. Initial symptoms appeared on lower leaves and inflorescences. Cleistothecia appeared inall green parts of grapevine. In 2002, and 2004, conditions were favourable for a secondary infection of bunches, leaves and canes from April to mid-July. Conditions for secondary infection were less favourable in the second half of June 2003. That year was characterized by warmer weather with less rainfall, especially in June and July. In 2004, precipitation and temperature were lower than in 2002, which resulted in a slightly less severe outbreak of disease.

  16. The effect of fungicide dose on the composition of laboratory populations of barley powdery mildew

    DEFF Research Database (Denmark)

    O'Hara, R.B.; Nielsen, B.J.; Østergård, Hanne

    2000-01-01

    , with the decline being more rapid in the population treated with the high dose, where one pathotype dominated the population after 31 generations. This pathotype was apparently not the fittest in the population treated with the low dose. This implies that knowledge of ED50 is not sufficient to predict pathotype...

  17. Comparative Studies on Callose Formation in Powdery Mildew Compatible and Incompatible Barley

    DEFF Research Database (Denmark)

    Skou, Jens-Peder; Jørgensen, Jørgen Helms; Lilholt, Ulla

    1984-01-01

    . This is the 1st case where the effect of callose refers to the action of a specific gene. Six susceptible Japanese varieties formed large appositions but they were initiated as late as in other susceptible varieties, and their color was paler than in other barleys. Nine Hordeum spp. [H. capense, H. chilense, H...

  18. Functions of EDS1-like and PAD4 genes in grapevine defenses against powdery mildew.

    Science.gov (United States)

    Gao, Fei; Dai, Ru; Pike, Sharon M; Qiu, Wenping; Gassmann, Walter

    2014-11-01

    The molecular interactions between grapevine and the obligate biotrophic fungus Erysiphe necator are not understood in depth. One reason for this is the recalcitrance of grapevine to genetic modifications. Using defense-related Arabidopsis mutants that are susceptible to pathogens, we were able to analyze key components in grapevine defense responses. We have examined the functions of defense genes associated with the salicylic acid (SA) pathway, including ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), EDS1-LIKE 2 (EDL2), EDL5 and PHYTOALEXIN DEFICIENT 4 (PAD4) of two grapevine species, Vitis vinifera cv. Cabernet Sauvignon, which is susceptible to E. necator, and V. aestivalis cv. Norton, which is resistant. Both VaEDS1 and VvEDS1 were previously found to functionally complement the Arabidopsis eds1-1 mutant. Here we show that the promoters of both VaEDS1 and VvEDS1 were induced by SA, indicating that the heightened defense of Norton is related to its high SA level. Other than Va/VvEDS1, only VaEDL2 complemented Arabidopsis eds1-1, whereas Va/VvPAD4 did not complement Arabidopsis pad4-1. Bimolecular fluorescence complementation results indicated that Vitis EDS1 and EDL2 proteins interact with Vitis PAD4 and AtPAD4, suggesting that Vitis EDS1/EDL2 forms a complex with PAD4 to confer resistance, as is known from Arabidopsis. However, Vitis EDL5 and PAD4 did not interact with Arabidopsis EDS1 or PAD4, correlating with their inability to function in Arabidopsis. Together, our study suggests a more complicated EDS1/PAD4 module in grapevine and provides insight into molecular mechanisms that determine disease resistance levels in Vitis species native to the North American continent.

  19. Functional Analysis of Barley Powdery Mildew Effector Candidates and Identification of their Barley Targets

    DEFF Research Database (Denmark)

    Ahmed, Ali Abdurehim

    about the function of many CSEPs in virulence and the identities of their host targets. In this PhD study, we investigated the function of nine CSEPs and found that CSEP0081, CSEP0105, CSEP0162 and CSEP0254 act as effectors by promoting the Bgh infection success. Independent silencing of these CSEPs...... to the cytosol and the nucleus of barley epidermal cells. Furthermore, CSEP0162 and CSEP0254 accumulated in the extrahaustorial matrix in Bgh-infected cells. This implies that their virulence targets may localize in the same cellular compartments. Using yeast two-hybrid screens, two barley small heat shock...... misfolding and aggregation. Through their chaperone activity, some sHsps contribute to pathogen defence by stabilizing intracellular proteins, including resistance and defence signalling proteins. In this study, we validated the chaperone activity of the barley Hsp16.9, which prevented the aggregation...

  20. The barley powdery mildew effector candidates CSEP0081 and CSEP0254 promote fungal infection success

    DEFF Research Database (Denmark)

    Ahmed, Ali Abdurehim; Pedersen, Carsten; Thordal-Christensen, Hans

    2016-01-01

    independent silencing of the transcripts for these CSEPs significantly reduced the fungal penetration and haustoria formation rate. Both CSEPs are likely required during and after the formation of haustoria, in which their transcripts were found to be differentially expressed, rather than in epiphytic tissue...

  1. Genetic dissection of a TIR-NB-LRR locus from the wild North American grapevine species Muscadinia rotundifolia identifies paralogous genes conferring resistance to major fungal and oomycete pathogens in cultivated grapevine.

    Science.gov (United States)

    Feechan, Angela; Anderson, Claire; Torregrosa, Laurent; Jermakow, Angelica; Mestre, Pere; Wiedemann-Merdinoglu, Sabine; Merdinoglu, Didier; Walker, Amanda R; Cadle-Davidson, Lance; Reisch, Bruce; Aubourg, Sebastien; Bentahar, Nadia; Shrestha, Bipna; Bouquet, Alain; Adam-Blondon, Anne-Françoise; Thomas, Mark R; Dry, Ian B

    2013-11-01

    The most economically important diseases of grapevine cultivation worldwide are caused by the fungal pathogen powdery mildew (Erysiphe necator syn. Uncinula necator) and the oomycete pathogen downy mildew (Plasmopara viticola). Currently, grapegrowers rely heavily on the use of agrochemicals to minimize the potentially devastating impact of these pathogens on grape yield and quality. The wild North American grapevine species Muscadinia rotundifolia was recognized as early as 1889 to be resistant to both powdery and downy mildew. We have now mapped resistance to these two mildew pathogens in M. rotundifolia to a single locus on chromosome 12 that contains a family of seven TIR-NB-LRR genes. We further demonstrate that two highly homologous (86% amino acid identity) members of this gene family confer strong resistance to these unrelated pathogens following genetic transformation into susceptible Vitis vinifera winegrape cultivars. These two genes, designated resistance to Uncinula necator (MrRUN1) and resistance to Plasmopara viticola (MrRPV1) are the first resistance genes to be cloned from a grapevine species. Both MrRUN1 and MrRPV1 were found to confer resistance to multiple powdery and downy mildew isolates from France, North America and Australia; however, a single powdery mildew isolate collected from the south-eastern region of North America, to which M. rotundifolia is native, was capable of breaking MrRUN1-mediated resistance. Comparisons of gene organization and coding sequences between M. rotundifolia and the cultivated grapevine V. vinifera at the MrRUN1/MrRPV1 locus revealed a high level of synteny, suggesting that the TIR-NB-LRR genes at this locus share a common ancestor. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  2. Using SSH Technology to Identify Relevant Genes Resistant to Cucumber Downy Mildew%利用SSH技术鉴定黄瓜抗霜霉病相关基因

    Institute of Scientific and Technical Information of China (English)

    刘大军; 秦智伟; 周秀艳; 辛明; 武涛

    2014-01-01

    Adopting SSH technology,this paper studied on the difference expressive genes of downy mildew resistant cucumber inbred line ‘M801-3-1’ before and after the infection of downy mildew.Disease-resistant cucumber material vaccinated downy mildew and unvaccinated cDNA library was constructed using SSH technology.Forty-eight positive clones were obtained by reverse Northern blot hybridization detection, and 14 UniESTs were obtained including 8 singletons and 6 contigs via molecular biology software.The SSH-EST genes function analysis indicated that oxidative stress resistance and chloroplast reconstruction and protection mechanisms had very important role on disease resistance.At the same time,the paper put forward that Clpb,HSP70,HSP22 and peptidyl-prolyl cis-trans isomerase might be involved in the R gene-mediated defense reaction,and smHSP might be the ‘defending target’ of R protein,responsible for monitoring intracellular exception.This study has provided a key evidence for revealing the relations between active oxygen mechanism and R gene mediate protection mechanism.%采用SSH技术对黄瓜抗霜霉病自交系M801-3-1侵染霜霉病菌前后的差异表达基因进行了研究。利用 SSH 技术构建抗病黄瓜材料接种霜霉病菌和未接种差异表达的差减cDNA文库。经反向Northern blot杂交检测,共得到48个阳性克隆。利用分子生物学软件对测序后的序列进行质量检测和聚类、拼接,共得到14个UniESTs,其中包括8个singletons和6个contigs。通过SSH-EST代表基因功能的分析,说明抗氧化胁迫能力和叶绿体的重建和保护机制对抗病品种抗病有重要作用。同时,提出SSH-EST代表的clpb、HSP70、HSP22和肽脯氨酰顺反异构酶还可能参与了R基因介导的防御反应,smHSP有可能就是R蛋白的“保卫靶”,负责监测细胞内的异常,这一发现为揭示活性氧机制和R基因介导的防卫机制之间的关系提供了关键证据。

  3. How Specific is Non-Hypersensitive Host and Nonhost Resistance of Barley to Rust and Mildew Fungi?

    Institute of Scientific and Technical Information of China (English)

    Niks R. E.

    2014-01-01

    Full nonhost resistance can be deifned as immunity, displayed by an entire plant species against all genotypes of a plant pathogen. Interesting biological questions are, whether the genes responsible for the nonhost status of a plant species have a general or a specific effectiveness to heterologous (“nonhost”) pathogens? Is the nonhost resistance to pathogens of plant species that are related to the nonhost based onR-genes or on other types of genes?We study this question in barley (Hordeum vulgareL.), which is a near-nonhost to several rusts (Puccinia) of cereals and grasses. By crosses and selection we accumulated susceptibility and developed an experimental line, SusPtrit, with high susceptibility to at least nine different heterologous rust taxa such as the wheat andAgropyron leaf rusts (P. triticina andP. persistens, respectively). At the microscopic level there is also some variation among barley accessions in the degree that the heterologous wheat powdery mildew (Blumeria graminisf.sp.tritici) is able to form haustoria in epidermal cells. So, also the genetics of the variation in level of nonhost resistance to heterologous mildew fungi can be studied in barley. Our data obtained on mapping populations involving three regular nonhost-immune accessions (Vada, Cebada Capa and Golden Promise) suggest that nonhost resistance is the joined effect of multiple, quantitative genes (QTLs) and very occasionally a major gene (R-gene?) is involved. Most QTLs have effect to only one or two heterologous rusts, but some have a wider spectrum. This was conifrmed in a set of QTL-NILs. Those QTL-NILs are used to ifne-map the effective genes. In some cases, a QTL region with effectiveness to several heterologous rusts might be a cluster of genes with a more narrow spectrum of effectiveness. Our evidence suggests that nonhost resistance in barley to rust and powdery mildew fungi of related Gramineae is not due toR-genes, but to pathogen species-speciifc quantitative

  4. Analysis of microsatellites from the transcriptome of downy mildew pathogens and their application for characterization of Pseudoperonospora populations

    Directory of Open Access Journals (Sweden)

    Emma C. Wallace

    2017-05-01

    Full Text Available Downy mildew pathogens affect several economically important crops worldwide but, due to their obligate nature, few genetic resources are available for genomic and population analyses. Draft genomes for emergent downy mildew pathogens such as the oomycete Pseudoperonospora cubensis, causal agent of cucurbit downy mildew, have been published and can be used to perform comparative genomic analysis and develop tools such as microsatellites to characterize pathogen population structure. We used bioinformatics to identify 2,738 microsatellites in the P. cubensis predicted transcriptome and evaluate them for transferability to the hop downy mildew pathogen, Pseudoperonospora humuli, since no draft genome is available for this species. We also compared the microsatellite repertoire of P. cubensis to that of the model organism Hyaloperonospora arabidopsidis, which causes downy mildew in Arabidopsis. Although trends in frequency of motif-type were similar, the percentage of SSRs identified from P. cubensis transcripts differed significantly from H. arabidopsidis. The majority of a subset of microsatellites selected for laboratory validation (92% produced a product in P. cubensis isolates, and 83 microsatellites demonstrated transferability to P. humuli. Eleven microsatellites were found to be polymorphic and consistently amplified in P. cubensis isolates. Analysis of Pseudoperonospora isolates from diverse hosts and locations revealed higher diversity in P. cubensis compared to P. humuli isolates. These microsatellites will be useful in efforts to better understand relationships within Pseudoperonospora species and P. cubensis on a population level.

  5. Genetics of resistance against lettuce downy mildew

    Science.gov (United States)

    Lettuce (Lactuca sativa) is one of the most valuable vegetable crops in the U.S. Downy mildew (DM), caused by Bremia lactucae, is the most important foliar disease of lettuce worldwide, which decreases the quality of the marketable portion of the crop. The use of resistant varieties carrying dominan...

  6. The Hibernation of the oak Mildew

    NARCIS (Netherlands)

    Kerling, L.C.P.

    1966-01-01

    The oak mildew invaded Western Europa in the years 1908 and 1909. Since then this parasite, Microsphaera alphitoides Griff. & Maubl. (syn. M. quercina (Schw.) Burr.) has occurred regularly in the Netherlands on oak seedlings and oak coppice, mainly Quercus pedunculata Ehr. (syn. Q. robur L. ). After

  7. Forecasting and management of hop downy mildew

    Science.gov (United States)

    Downy mildew of hop, caused by Pseudoperonospora humuli, is managed in the Pacific Northwestern U.S. by regular application of fungicides. A degree-day model that forecasts the first emergence of shoots systemically infection with P. humuli (termed basal spikes) and a risk index for secondary sprea...

  8. Association of RGA-SSCP markers with resistance to downy mildew and anthracnose in grapevines.

    Science.gov (United States)

    Tantasawat, P A; Poolsawat, O; Prajongjai, T; Chaowiset, W; Tharapreuksapong, A

    2012-07-02

    Downy mildew (Plasmopara viticola) and anthracnose (Sphaceloma ampelinum) are two major diseases that severely affect most grapevine (Vitis vinifera) cultivars grown commercially in Thailand. Progress of conventional breeding programs of grapevine for improved resistance to these diseases can be speeded up by selection of molecular markers associated with resistance traits. We evaluated the association between 13 resistance gene analog (RGA)-single-strand conformation polymorphism (SSCP) markers with resistance to downy mildew and anthracnose in 71 segregating progenies of seven cross combinations between susceptible cultivars and resistant lines. F(1) hybrids from each cross were assessed for resistance to downy mildew and anthracnose (isolates Nk4-1 and Rc2-1) under laboratory conditions. Association of resistance traits with RGA-SSCP markers was evaluated using simple linear regression analysis. Three RGA-SSCP markers were found to be significantly correlated with anthracnose resistance, whereas significant correlation with downy mildew resistance was observed for only one RGA-SSCP marker. These results demonstrate the usefulness of RGA-SSCP markers. Four candidate markers with significant associations to resistance to these two major diseases of grapevine were identified. However, these putative associations between markers and resistance need to be verified with larger segregating populations before they can be used for marker-assisted selection.

  9. Epidemiology of Basil Downy Mildew.

    Science.gov (United States)

    Cohen, Yigal; Ben Naim, Yariv; Falach, Lidan; Rubin, Avia E

    2017-06-09

    Basil downy mildew (BDM) caused by the oomycete Peronospora belbahrii is a destructive disease of sweet basil (Ocimum basilicum) worldwide. It originated in Uganda in the 1930s and recently spread to Europe, the Middle East, Americas, and the Far East. Seed transmission may be responsible for its quick global spread. The pathogen attacks leaf blades, producing chlorotic lesions with ample dark asexual spores on the lower leaf surface. Oospores may form in the mesophyll of infected leaves. The asexual spores germinate on a wet leaf surface within 2 h and penetrate into the epidermis within 4 h. Spore germination and infection occur at a wide range of temperatures from 5 to 28.5°C. Infection intensity depends on the length of dew period, leaf temperature, and inoculum dose. The duration of latent period (from infection to sporulation) extends from 5 to 10 days, depending on temperature and light regime. The shortest is 5 days at 25°C under continuous light. Sporulation requires high humidity but not free leaf wetness. Sporulation occurs at 10 to 26°C. At the optimum temperature of 18°C, the process of sporulation requires 7.5 h at relative humidity ≥ 85%, with 3 h for sporophores emergence from stomata and 4.5 h for spore formation. Sporophores can emerge under light or darkness, but spore formation occurs in the dark only. Limited data are available on spore dispersal. Spores dispersed from sporulating plants contaminate healthy plants within 2 h of exposure. Settled spores may survive on leaf surface of healthy plants for prolonged periods, depending on temperature. Seed transmission of the disease occurs in Europe, but not in Israel or the United States. P. belbahrii in Israel also attacks species belonging to Rosemarinus, Nepeta, Agastache, Micromeria, and Salvia but not Plectranthus (coleus). A Peronospora species that infects coleus does not infect sweet basil. Control of BDM includes chemical, physical, and genetic means. The fungicide mefenoxam was

  10. Novas raças de Bremia lactucae, agente causador do míldio da alface, identificadas no estado de São Paulo New races of Bremia lactucae, causal agent of lettuce downy mildew, identified in São Paulo state, Brazil

    Directory of Open Access Journals (Sweden)

    Jean de O Souza

    2011-09-01

    Full Text Available O objetivo deste trabalho foi relatar o surgimento de raças de Bremia lactucae, agente causal do míldio nas principais regiões produtoras de alface do estado de São Paulo. O estudo foi realizado no Laboratório de Melhoramento Genético de Hortaliças do Departamento de Produção Vegetal da UNESP, Campus de Jaboticabal. No período de 2006 e 2007, foram coletados 36 isolados de B. lactucae de diferentes regiões produtoras de alface no estado. Para identificação das raças foram utilizadas as cultivares diferenciadoras conforme o código "Sextet". Foram identificadas três novas raças, SPBl:02, SPBl:03 e SPBl:04 com os referidos comportamentos do fungo: (63/31/19/00, (63/63/19/00 e (63/63/03/00. Os genes Dm-14, Dm-17, Dm-18, Dm-37 e Dm-38 conferem resistência a essas novas raças identificadas.The objective of this paper was to report new races of lettuce downy mildew causal agent Bremia lactucae in São Paulo State. The study was carried out in the laboratory of Crop Genetics in the Department of Crop Science at the college of Agricultural and Veterinary Sciences, Jaboticabal campus. A total of 36 isolates of B. lactucae was collected in different regions. The identification of races was based on compatibility reaction on the differential cultivars of the "Sextet". Three new races of B. lactucae, SPBl:02 (63/31/19/00, SPBl:03 (63/63/19/00 and SPBl:04 (63/63/03/00 were identified according to "Sextet" code. Genes Dm-14, Dm-17, Dm-18, Dm-37 and Dm-38 confer resistance to these new races identified.

  11. Epidemiology and control of spinach downy mildew in coastal California

    Science.gov (United States)

    The most serious threat to global fresh market spinach production is spinach downy mildew, caused by the obligate biotrophic pathogen, Peronospora effusa. Downy mildew causes yellow chlorotic lesions on spinach leaf tissue, often accompanied by abundant sporulation on the undersides of leaves. Very ...

  12. Peroxidase profiling reveals genetic linkage between peroxidase gene clusters and basal host and non-host resistance to rusts and mildew in barley.

    Directory of Open Access Journals (Sweden)

    Ana M González

    Full Text Available BACKGROUND: Higher plants possess a large multigene family encoding secreted class III peroxidase (Prx proteins. Peroxidases appear to be associated with plant disease resistance based on observations of induction during disease challenge and the presence or absence of isozymes in resistant vs susceptible varieties. Despite these associations, there is no evidence that allelic variation of peroxidases directly determines levels of disease resistance. METHODOLOGY/PRINCIPAL FINDINGS: The current study introduces a new strategy called Prx-Profiling. We showed that with this strategy a large number of peroxidase genes can be mapped on the barley genome. In order to obtain an estimate of the total number of Prx clusters we followed a re-sampling procedure, which indicated that the barley genome contains about 40 peroxidase gene clusters. We examined the association between the Prxs mapped and the QTLs for resistance of barley to homologous and heterologous rusts, and to the barley powdery mildew fungus. We report that 61% of the QTLs for partial resistance to P. hordei, 61% of the QTLs for resistance to B. graminis and 47% of the QTLs for non-host resistance to other Puccinia species co-localize with Prx based markers. CONCLUSIONS/SIGNIFICANCE: We conclude that Prx-Profiling was effective in finding the genetic location of Prx genes on the barley genome. The finding that QTLs for basal resistance to rusts and powdery mildew fungi tend to co-locate with Prx clusters provides a base for exploring the functional role of Prx-related genes in determining natural differences in levels of basal resistance.

  13. Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

    OpenAIRE

    Zhang, N.

    2008-01-01

    Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29 Backcross Inbred Lines (BILs) representing in total 96% of the L. saligna genome, 15 introgressions were identified to contribute to this resistance at one to four tested lettuce developmental stages and ...

  14. Occurrence of a black mildew in Santalum album plantation at Anakulam, Thiruvananthapuram, Kerala, India

    Directory of Open Access Journals (Sweden)

    V.B. Hosagoudar

    2013-06-01

    Full Text Available The Anakulam sub-unit of the Trivandrum Division of the Kerala Forest Development Corporation has planted 7.84 ha of sandal wood trees in Block V, including the plantation of 5200 plants in the year 2010 and 3000 plants during the year 2011 at a spacing of 3x3m. This area is located at an altitude of 300m. The entire sandal wood plantation is being affected with a black mildew fungus, identified as Asterina congesta.

  15. Occurrence of a black mildew in Santalum album plantation at Anakulam, Thiruvananthapuram, Kerala, India

    Directory of Open Access Journals (Sweden)

    V.B. Hosagoudar

    2013-06-01

    Full Text Available The Anakulam sub-unit of the Trivandrum Division of the Kerala Forest Development Corporation has planted 7.84 ha of sandal wood trees in Block V, including the plantation of 5200 plants in the year 2010 and 3000 plants during the year 2011 at a spacing of 3x3m. This area is located at an altitude of 300m. The entire sandal wood plantation is being affected with a black mildew fungus, identified as Asterina congesta.

  16. Response of container-grown flowering dogwood cultivars to powdery mildew under sun/shade production and different fertilizer regimes

    Science.gov (United States)

    Container-grown dogwoods are an important product in the nursery and landscape industry and rank third in the US in nursery sales of ornamental trees. Dogwoods are a challenging crop to produce in container culture mainly due to fertilizer, water, and shade management. Our experiments indicate that ...

  17. Effect of rain on the development of wheat powdery mildew (Erysiphe graminis DC. f. sp. tritici Marchal)

    Energy Technology Data Exchange (ETDEWEB)

    Merchan, V.M.; Kranz, J.

    1986-01-01

    The effect of simulated and natural rain on colony growth and production of conidia as well as on germination and infection efficiency of daily produced conidia of individual colonies of Erysiphe graminis f. sp. tritici has been studied at 14 and 20/sup 0/C. In growth chambers, the development of colonies was not markedly affected by daily applications of varying levels of distilled water when applied as small droplets (< 2 mm 0) and low terminal velocity. However, the infection efficiency of newly formed conidia was reduced, mainly by a washing-off effect, and, thus, the number of daughter colonies lower. This could also be found in the field already with low intensities of rain. Heavy precipitation, through the high terminal velocity of large droplets, impaired colony growth partially or totally. But occasionally, even with 14.3 mm rainfall, it was observed that, due to appropriate positioning, leaves with colonies were not directly wetted. In such cases, colonies remained dry and spore dispersal was not hampered.

  18. Lessons from a phenotyping center revealed by the genome-guided mapping of powdery mildew resistance loci

    Science.gov (United States)

    The genomics era brought unprecedented tools for genetic analysis of host resistance, but careful attention is needed on obtaining accurate and reproducible phenotypes so that genomic results appropriately reflect biology. Phenotyping host resistance by natural infection in the field can produce var...

  19. Early detection and classification of powdery mildew-infected rose leaves using ANFIS based on extracted features of thermal images

    Science.gov (United States)

    Jafari, Mehrnoosh; Minaei, Saeid; Safaie, Naser; Torkamani-Azar, Farah

    2016-05-01

    Spatial and temporal changes in surface temperature of infected and non-infected rose plant (Rosa hybrida cv. 'Angelina') leaves were visualized using digital infrared thermography. Infected areas exhibited a presymptomatic decrease in leaf temperature up to 2.3 °C. In this study, two experiments were conducted: one in the greenhouse (semi-controlled ambient conditions) and the other, in a growth chamber (controlled ambient conditions). Effect of drought stress and darkness on the thermal images were also studied in this research. It was found that thermal histograms of the infected leaves closely follow a standard normal distribution. They have a skewness near zero, kurtosis under 3, standard deviation larger than 0.6, and a Maximum Temperature Difference (MTD) more than 4. For each thermal histogram, central tendency, variability, and parameters of the best fitted Standard Normal and Laplace distributions were estimated. To classify healthy and infected leaves, feature selection was conducted and the best extracted thermal features with the largest linguistic hedge values were chosen. Among those features independent of absolute temperature measurement, MTD, SD, skewness, R2l, kurtosis and bn were selected. Then, a neuro-fuzzy classifier was trained to recognize the healthy leaves from the infected ones. The k-means clustering method was utilized to obtain the initial parameters and the fuzzy "if-then" rules. Best estimation rates of 92.55% and 92.3% were achieved in training and testing the classifier with 8 clusters. Results showed that drought stress had an adverse effect on the classification of healthy leaves. More healthy leaves under drought stress condition were classified as infected causing PPV and Specificity index values to decrease, accordingly. Image acquisition in the dark had no significant effect on the classification performance.

  20. A component of the Sec61 ER protein transporting pore is required for plant susceptibility to powdery mildew

    DEFF Research Database (Denmark)

    Zhang, Wen-Jing; Hanisch, Susanne; Kwaaitaal, Mark Adrianus Cornelis J

    2013-01-01

    , which was found to be in close proximity to the EHM around the haustorial body, but not the haustorial fingers. This differential EHM proximity suggests that the ER, including HvSec61βa, may be actively recruited by the haustorium, potentially to provide efficient effector transfer to the cytosol...

  1. Regulation of basal resistance by a powdery mildew-induced cysteine-rich receptor-like protein kinase in barley

    DEFF Research Database (Denmark)

    Rayapuram, Cbgowda; Jensen, Michael K; Maiser, Fabian

    2012-01-01

    , followed by a rather short 17-amino-acid transmembrane domain, which includes an AAA motif, two features characteristic of endoplasmic reticulum (ER)-targeted proteins and, finally, a characteristic putative protein kinase domain in the C-terminus. The HvCRK1 transcript was isolated from leaves inoculated...

  2. Suppression of resistance to Erysiphe graminis f.sp. hordei conferred by the mlo5 barley powdery mildew resistance gene

    DEFF Research Database (Denmark)

    Lyngkjær, M.F.; Carver, T.L.W.; Zeyen, R.J.

    1997-01-01

    . Additional suppression of mlo5 penetration resistance against the avirulent E. graminis isolate was achieved by using DDG, mannose, or glucose in combination with the phenylalanine ammonia lyase inhibitor alpha-aminooxy-beta-phenylpropionic acid (AOPP). A mlo virulent isolate of E. graminis was also tested...... phenolic compound synthesis, but that phenolics are not responsible for the primary mechanism of mlo5 penetration resistance. Sequestration of phosphate ions caused by complexing with DDG or mannose may lower the energy available for penetration resistance in these barley lines, obviating both inherent...

  3. Genetic dissection of powdery mildew resistance in interspecific half-sib grapevine families using SNP-based maps

    Science.gov (United States)

    Quantitative trait locus (QTL) identification in perennial fruit crops is impeded largely by their lengthy generation time, resulting in costly and labor-intensive maintenance of breeding programs. In a grapevine (genus Vitis) breeding program, although experimental families are typically unreplicat...

  4. Genetic diversity among Lagenaria siceraria accessions containing resistance to root-knot nematodes, whiteflies, ZYMV or powdery mildew

    Science.gov (United States)

    In recent years, there has been an increased interest in Europe and in the U.S. in grafting watermelon onto bottle gourd, Lagenaria siceraria (Mol.) Standl. In this study, genetic diversity and relationships were examined [using 240 sequence related amplified polymorphism (SRAP) markers] among 56 U...

  5. The composition, anti-mildew and anti-wood-decay fungal activities of the leaf and fruit oils of Juniperus formosana from Taiwan.

    Science.gov (United States)

    Su, Yu-Chang; Hsu, Kuan-Ping; Wang, Eugene I-Chen; Ho, Chen-Lung

    2013-09-01

    In this study, anti-mildew and anti-wood-decay fungal activities of the leaf and fruits essential oil and its constituents from Juniperus formosana were evaluated in vitro against seven mildew fungi and four wood decay fungi, respectively. The main compounds responsible for the anti-mildew and anti-wood-decay fungal activities were also identified. The essential oil from the fresh leaves and fruits of J. formosana were isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS, respectively. The leaf oil mainly consisted of alpha-pinene (41.0%), limonene (11.5%), alpha-cadinol (11.0%), elemol (6.3%), and beta-myrcene (5.8%); the fruit oil was mostly alpha-pinene (40.9%), beta-myrcene (32.4%), alpha-thujene (5.9%) and limonene (5.9%). Comparing the anti-mildew and anti-wood-decay fungal activities of the oils suggested that the leaf oil was the most effective. For the anti-mildew and anti-wood-decay fungal activities of the leaf oil, the active source compounds were determined to be alpha-cadinol and elemol.

  6. Characterization of Particle Size Distributions of Powdery Building Material Aerosol Generated by Fluidization and Gravitation

    Directory of Open Access Journals (Sweden)

    Tadas Prasauskas

    2012-10-01

    Full Text Available This study aims to identify particle size distributions (PSD of aerosol of powdery building materials commonly used in construction work (cement, chalk, clay, wood sawdust, wood grinding dust, gypsum, hydrated lime, masonry grout, quartz sand, sand and structural lime by two aerosolization methods: fluidization and gravitation. Fluidization and gravitation methods represent industrial activities such as pneumotransportation and unloading. Both particle resuspension mechanisms have been modelled in laboratory conditions. The particle size distributions of resuspended particulate matter from powdery building materials were rather similar identified by both fluidization and gravitation methods, with an exception of wood sawdust and sand. The PM10 fraction ranged between 30% and 87%, PM2.5 from 7% to 28% and PM1.0 from 3% to 7% of the total mass of particulate matter. The highest PM10/PMtotal ratio was calculated for masonry grout - 0.87, and the lowest ratio for quartz sand - 0.30. The highest ratio of PM2.5/PMtotal was calculated for sand - 0.23, the lowest for quartz sand - 0.07. Substantial quantities of PM2.5 were found to be emitted implying a potential threat to human health.DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1519

  7. Downy mildew resistance induced by Trichoderma harzianum T39 in susceptible grapevines partially mimics transcriptional changes of resistant genotypes

    Directory of Open Access Journals (Sweden)

    Perazzolli Michele

    2012-11-01

    Full Text Available Abstract Background Downy mildew, caused by Plasmopara viticola, is one of the most severe diseases of grapevine and is commonly controlled by fungicide treatments. The beneficial microorganism Trichoderma harzianum T39 (T39 can induce resistance to downy mildew, although the molecular events associated with this process have not yet been elucidated in grapevine. A next generation RNA sequencing (RNA-Seq approach was used to study global transcriptional changes associated with resistance induced by T39 in Vitis vinifera Pinot Noir leaves. The long-term aim was to develop strategies to optimize the use of this agent for downy mildew control. Results More than 14.8 million paired-end reads were obtained for each biological replicate of T39-treated and control leaf samples collected before and 24 h after P. viticola inoculation. RNA-Seq analysis resulted in the identification of 7,024 differentially expressed genes, highlighting the complex transcriptional reprogramming of grapevine leaves during resistance induction and in response to pathogen inoculation. Our data show that T39 has a dual effect: it directly modulates genes related to the microbial recognition machinery, and it enhances the expression of defence-related processes after pathogen inoculation. Whereas several genes were commonly affected by P. viticola in control and T39-treated plants, opposing modulation of genes related to responses to stress and protein metabolism was found. T39-induced resistance partially inhibited some disease-related processes and specifically activated defence responses after P. viticola inoculation, causing a significant reduction of downy mildew symptoms. Conclusions The global transcriptional analysis revealed that defence processes known to be implicated in the reaction of resistant genotypes to downy mildew were partially activated by T39-induced resistance in susceptible grapevines. Genes identified in this work are an important source of markers

  8. Study on the Motion state of Powdery materials in Dense-phase Pneumatic Conveying Pipe

    Directory of Open Access Journals (Sweden)

    Lia Zhihua

    2016-01-01

    Full Text Available Using the method of computational fluid dynamics, a model is created about powdery materials flowing in the dense-phase pneumatic conveying pipe. the motion state powdery materials flowing in the horizontal and vertical pipe is simulated. It is found that in the horizontal pipe the powdery materials represent the flow of dune-like state, and continuously move forward in this form, the volume fraction of powdery materials at the pipe's bottom is large, the velocity is low; In the vertical pipe, the columnar solid-plug can form and scatter continuously, and the motion state is closer to fluidization.

  9. Lactuca saligna, a non-host for lettuce downy mildew (Bremia lactucae), harbors a new race-specific Dm gene and three QTL's for resistance

    NARCIS (Netherlands)

    Jeuken, M.J.W.; Lindhout, P.

    2002-01-01

    Lactuca sativa (lettuce) is susceptible to Bremia lactucae (downy mildew). In cultivated and wild Lactuca species, Dm genes have been identified that confer race-specific resistance. However, these genes were soon rendered ineffective by adaptation of the pathogen. Lactuca saligna (wild lettuce) is

  10. Transcriptome and Small RNAome Dynamics during a Resistant and Susceptible Interaction between Cucumber and Downy Mildew

    Directory of Open Access Journals (Sweden)

    Alyssa Burkhardt

    2016-03-01

    Full Text Available Cucumber ( L. downy mildew, caused by the obligate oomycete pathogen (Berk. and Curt. Rostov., is the primary factor limiting cucumber production. Although sources of resistance have been identified, such as plant introduction line PI 197088, the genes and processes involved in mediating resistance are still unknown. In the current study, we conducted a comprehensive transcriptome and small RNAome analysis of a resistant (PI 197088 and susceptible (‘Vlaspik’ cucumber during a time course of infection using Illumina sequencing. We identified significantly differentially expressed (DE genes within and between resistant and susceptible cucumber leaves over a time course of infection. Weighted gene correlation network analyses (WGCNA created coexpression modules containing genes with unique expression patterns between Vlaspik and PI 197088. Recurring data trends indicated that resistance to cucumber downy mildew is associated with earlier response to the pathogen, hormone signaling, and regulation of nutrient supply. Candidate resistance genes were identified from multiple transcriptome analyses and literature support. Additionally, parallel sequencing of small RNAs (sRNAs from cucumber and during the infection time course was used to identify and quantify novel and existing microRNA (miRNA in both species. Predicted miRNA targets of cucumber transcripts suggest a complex interconnectedness of gene expression regulation in this plant–pathogen system. This work bioinformatically uncovered gene expression patterns involved in the mediation of or response to resistance. Herein, we provide the foundation for future work to validate candidate resistance genes and miRNA-based regulation proposed in this study.

  11. Comparison of three fungicide spray advisories for lettuce downy mildew

    NARCIS (Netherlands)

    Wu, B.M.; Subbarao, K.V.; Bruggen, van A.H.C.; Koike, S.T.

    2001-01-01

    Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform satisfactoril

  12. Extracts of Inula viscosa Control Downy Mildew of Grapes Caused by Plasmopara viticola.

    Science.gov (United States)

    Cohen, Yigal; Wang, Wenqiao; Ben-Daniel, Bat-Hen; Ben-Daniel, Yigal

    2006-04-01

    ABSTRACT The oily paste extracts of Inula viscosa leaves made with organic solvents were effective in controlling downy mildew caused by Plasmopara viticola in detached leaf tissues of grapes in growth chambers. Thin-layer chromatography of such extracts revealed the presence of 11 Rf regions of which four contained highly effective compounds against the disease. Two major inhibitory compounds, each comprising 10.6% of the total paste weight, were identified as tomentosin and costic acid. An emulsified concentrate formulation of the oily paste extracts provided excellent activity against the disease in the field. The effective dose (concentration) required for 90% control of the disease in treated shoots in the field was below 0.125% (paste in water). No seasonal fluctuations were observed in the control efficacy of six extracts made from I. viscosa leaves harvested during the period of May to July. In whole vines, treated and artificially inoculated, the paste concentration required for 90% control of the disease ranged between 0.30 to 0.37%, whereas in naturally infected vines it was 0.58%. It appears that I. viscosa is a valuable source for fungicidal preparations against downy mildew of grapes. This is the first report on the control of a disease with I. viscosa extracts under field conditions.

  13. Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce.

    Science.gov (United States)

    Simko, Ivan; Atallah, Amy J; Ochoa, Oswaldo E; Antonise, Rudie; Galeano, Carlos H; Truco, Maria Jose; Michelmore, Richard W

    2013-10-07

    Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids.

  14. Development of a compact powdery sample negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Motoi [Doshisha Univ., Tanabe, Kyoto (Japan). Faculty of Engineering; Sasao, Mamiko; Kawano, Hiroyuki

    1997-02-01

    A gas-feed-free compact negative ion source can be realized by utilizing the process of electron stimulated desorption from powdery sample. A negative ion source of this type is designed to be attached to a standard 1.33 inch copper-gasket-flange. The ion source is operated stable with LiH powder for more than 10 hours with the mass-separated negative hydrogen ion current of 1 nA. The source causes minute gas emission, and particularly suitable for ion beam applications in which a good vacuum is required. The present status of the compact ion source development is briefly described. (author)

  15. Inactivation of mildew in rough rice and wheat by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jun, E-mail: jwang@zju.edu.c [Department of Biosystems Engineering, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029 (China); Yu Yong [Department of Biosystems Engineering, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029 (China)

    2010-06-15

    Rough rice and wheat were irradiated by gamma ray ({sup 60}Co) with different doses and the mildew inactivation efficacy was investigated after 0, 6 and 12 month storage. Five genera of mildew in rough rice and wheat were detected, including Alternaria, Fusarium, Aspergillus, Penicillium and Rhizopus. For Aspergillus, four genera of mold were detected, including Aspergillus Kawachii, Aspergillus glaucus, Aspergillus niger, Aspergillus flavus. Detection rates of the five genera of mildew and four genera of Aspergillus were all reduced with increasing dose after 0, 6 and 12 months storage. The detection rates of the other four genera of mildew had no significant change during storage.

  16. Genome analyses of the sunflower pathogen Plasmopara halstedii provide insights into effector evolution in downy mildews and Phytophthora

    NARCIS (Netherlands)

    Sharma, Rahul; Xia, Xiaojuan; Cano, Liliana M; Evangelisti, Edouard; Kemen, Eric; Judelson, Howard; Oome, Stan; Sambles, Christine; van den Hoogen, D Johan; Kitner, Miloslav; Klein, Joël; Meijer, Harold J G; Spring, Otmar; Win, Joe; Zipper, Reinhard; Bode, Helge B; Govers, Francine; Kamoun, Sophien; Schornack, Sebastian; Studholme, David J; Van den Ackerveken, Guido; Thines, Marco

    2015-01-01

    BACKGROUND: Downy mildews are the most speciose group of oomycetes and affect crops of great economic importance. So far, there is only a single deeply-sequenced downy mildew genome available, from Hyaloperonospora arabidopsidis. Further genomic resources for downy mildews are required to study thei

  17. Resistance Against Basil Downy Mildew in Ocimum Species.

    Science.gov (United States)

    Ben-Naim, Yariv; Falach, Lidan; Cohen, Yigal

    2015-06-01

    Downy mildew, caused by the oomycete Peronospora belbahrii, is a devastating disease of sweet basil. In this study, 113 accessions of Ocimum species (83 Plant Introduction entries and 30 commercial entries) were tested for resistance against downy mildew at the seedling stage in growth chambers, and during three seasons, in the field. Most entries belonging to O. basilicum were highly susceptible whereas most entries belonging to O. americanum, O. kilimanadascharicum, O. gratissimum, O. campechianum, or O. tenuiflorum were highly resistant at both the seedling stage and the field. Twenty-seven highly resistant individual plants were each crossed with the susceptible sweet basil 'Peri', and the F1 progeny plants were examined for disease resistance. The F1 plants of two crosses were highly resistant, F1 plants of 24 crosses were moderately resistant, and F1 plants of one cross were susceptible, suggesting full, partial, or no dominance of the resistance gene(s), respectively. These data confirm the feasibility of producing downy mildew-resistant cultivars of sweet basil by crossing with wild Ocimum species.

  18. Effects of stacked quantitative resistances to downy mildew in lettuce do not simply add up

    NARCIS (Netherlands)

    Boer, den E.; Pelgrom, K.T.B.; Zhang, N.; Visser, R.G.F.; Niks, R.E.; Jeuken, M.J.W.

    2014-01-01

    Key message In a stacking study of eight resistance QTLs in lettuce against downy mildew, only three out of ten double combinations showed an increased resistance effect under field conditions. Abstract Complete race nonspecific resistance to lettuce downy mildew, as observed for the nonhost wild le

  19. Simple Sequence Repeat Markers Useful for Sorghum Downy Mildew (Peronosclerospora sorghi) and Related Species

    Science.gov (United States)

    A recent outbreak of sorghum downy mildew, in Texas, has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically poin...

  20. Inhibition of Blumeria graminis germination and germling development within colonies of oat mildew

    DEFF Research Database (Denmark)

    Carver, T.L.W.; Roberts, P.C.; Thomas, B.J.;

    2001-01-01

    established oat mildew colonies, most formed abnormal, hypha-like germ tubes. Since they did not form appressoria, and ere thus Unable to attempt penetration, it was impossible to determine whether oat mildew colonies induced accessibility of underlying oat epidermal cells. However, when superficial...... ff. spp. formed normal appressoria. This was also true When conidia germinated within established barley mildew colonies. Within barley mildew colonies, appressoria of f. sp. hordei penetrated epidermal cells formed haustoria more frequently than appressoria distant from colonies. Similarly, ff. spp...... structures of established colonies were removed, germlings of all ff. spp. formed appressoria freely,, on cells containing oat mildew colony haustoria. Furthermore, these cells showed high level induced accessibility not only to f. sp. avenae but also to the normally non-pathogenic ff, spp. This indicated...

  1. Simultaneous powdery boronaluminizing of steel stable in aluminum melts

    Energy Technology Data Exchange (ETDEWEB)

    Zakhariev, Z. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev str., Bl.11, 1113 Sofia (Bulgaria)], E-mail: zahary19@mail.bg; Marinov, M.; Penyashki, T.; Tsokov, Pl. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev str., Bl.11, 1113 Sofia (Bulgaria)

    2008-07-14

    The corrosion resistance of a boron-aluminized carbon steel C45 in aluminum melt has been investigated. Simultaneous saturation with aluminum and boron has been performed with different powdery mixtures. Simultaneous boronizing and aluminizing of steels has been found possible, layers of up to 1 mm thickness being obtained. Corrosion tests have shown the advantages of the two-component layers obtained by the alumothermic method (Al{sub 2}O{sub 3} + Al + B{sub 2}O{sub 3} + NaF) as compared to other saturating mixtures and especially single-component boronizing with EKabor. It has been shown that the two-component boron-aluminized layer can be used for protecting usual carbon steels in aluminum melts.

  2. 78 FR 9027 - Notice of Decision To Authorize the Importation of Litchi, Longan, and Rambutan From the...

    Science.gov (United States)

    2013-02-07

    ... additional declaration stating that the consignment was inspected and found free of the powdery mildew Oidium... stating that the consignment was inspected and found free of the powdery mildew Oidium nephelii; and...

  3. 75 FR 57019 - Pesticide Product Registrations; Conditional Approval

    Science.gov (United States)

    2010-09-17

    ... leaf spot, leaf spot, powdery mildew, and soybean rust, and on apples to control cedar apple rust, powdery mildew, quince rust, and scab. List of Subjects Environmental protection, Chemicals, Pests...

  4. 77 FR 13260 - Notice of Availability of a Pest Risk Analysis for the Importation of Litchi, Longan, and...

    Science.gov (United States)

    2012-03-06

    ... additional declaration stating that the consignment was inspected and found free of the powdery mildew Oidium... stating that the consignment was inspected and found free of the powdery mildew Oidium nephelii; and...

  5. Nocturnal Fanning Suppresses Downy Mildew Epidemics in Sweet Basil.

    Science.gov (United States)

    Cohen, Yigal; Ben-Naim, Yariv

    2016-01-01

    Downy mildew is currently the most serious disease of sweet basil around the world. The oomycete causal agent Peronospora belbahrii requires ≥ 4h f