ABSTRACT: Identification of avirulence genes in the barley powdery mildew fungus (Bgh) by RNA-sequencing and transcriptome-wide association analysis on a set of Bgh isolates
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012. Molecular Plant Pathology 13 (4): 414-430. DOI: 10.1111/j.1364-3703.2011.00783.x). Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to identify small RNAs (sRNAs) from both barley and Bgh that regulate gene expression both within species and cross-kingdom.
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012. Molecular Plant Pathology 13 (4): 414-430. DOI: 10.1111/j.1364-3703.2011.00783.x). Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to discover novel transcripts expressed following barley infection with blumeria.
Project description:The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012. Molecular Plant Pathology 13 (4): 414-430. DOI: 10.1111/j.1364-3703.2011.00783.x). Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to identify small RNA-derived transcript cleavage sites from both barley and Bgh that regulate gene expression at the post-transcriptional level both within species and cross-kingdom.
Project description:Purpose: The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al., 2012). B. graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.). We sought to address the temporal regulation of membrane trafficking associated gene expression in barley-powdery mildew interactions. We created an isogenic panel of immune signaling mutants to address three main questions: (i) which Blumeria secreted proteins are differentially regulated in response to different compromised genotypes, (ii) which barley membrane trafficking genes are altered in response to pathogen attack, and (iii) how are these genes interacting across genotypes and infection stages.
Project description:Powdery mildew is a very common plant disease and only few plants are immune. Host interactions have been identified and characterized for the pathosystems barley-B. graminis f. sp. tritici (Bgt) and wheat-B. graminis f. sp. hordei (Bgh), whereas no data are reported about powdery mildew and nonhost plants, such as rice. On the other hand rice nonhost resistance is widely unexploited and only few expression data are available. To characterize rice response during nonhost interaction with Bgh, a global expression analysis was performed by using the GeneChip® Rice Genome Array. To describe rice gene expression profiles during nonhost interaction, 2 week-old rice plantlets were inoculated with Bgh. Treated (inoculated) and control (mock) samples were collected 24 hours post-inoculation for GeneChip® Rice Genome Array hybridization.
Project description:We performed RNA-sequencing of Bgh-infected barley leaves at two different time-points after infection to examine gene expression in the barley powdery mildew isolate DH14 during plant pathogenesis.
Project description:Powdery mildew is a very common plant disease and only few plants are immune. Host interactions have been identified and characterized for the pathosystems barley-B. graminis f. sp. tritici (Bgt) and wheat-B. graminis f. sp. hordei (Bgh), whereas no data are reported about powdery mildew and nonhost plants, such as rice. On the other hand rice nonhost resistance is widely unexploited and only few expression data are available. To characterize rice response during nonhost interaction with Bgh, a global expression analysis was performed by using the GeneChipM-BM-. Rice Genome Array. To describe rice gene expression profiles during nonhost interaction, 2 week-old rice plantlets were inoculated with Bgh. Treated (inoculated) and control (mock) samples were collected 24 hours post-inoculation for GeneChipM-BM-. Rice Genome Array hybridization. For transcript proM-oM-,M-^Aling experiments with powdery mildew, entire leaves were sampled from rice plantlets 2 weeks old (cv. Nipponbare). Treated and control (mock) rice leaves were collected 24 hours post inoculation. Three biological replicates for inoculated and control plants were extracted and analysed independently with the GeneChipM-BM-. Rice Genome Array.
Project description:Arabidopsis does not support the growth and asexual reproduction of the barley pathogen, Blumeria graminis f. sp. hordei Bgh). A majority of germlings fail to penetrate the epidermal cell wall and papillae. To gain additional insight into this interaction, we determined whether the salicylic acid (SA) or jasmonate (JA)/ethylene (ET) defence pathways played a role in blocking barley powdery mildew infections. Only the eds1 mutant and NahG transgenics supported a modest increase in penetration success by the barley powdery mildew. We also compared the global gene expression patterns of Arabidopsis inoculated with the non-host barley powdery mildew to those inoculated with a virulent, host powdery mildew, Erysiphe cichoracearum. Genes repressed by inoculations with non-host and host powdery mildews relative to non-inoculated control plants accounted for two-thirds of the differentially expressed genes. A majority of these genes encoded components of photosynthesis and general metabolism. Consistent with this observation, Arabidopsis growth was inhibited following inoculation with Bgh, suggesting a shift in resource allocation from growth to defence. A number of defence-associated genes were induced during both interactions. These genes likely are components of basal defence responses, which do not effectively block host powdery mildew infections. In addition, genes encoding defensins, anti-microbial peptides whose expression is under the control of the JA/ET signalling pathway, were induced exclusively by non-host pathogens. Ectopic activation of JA/ET signalling protected Arabidopsis against two biotrophic host pathogens. Taken together, these data suggest that biotrophic host pathogens must either suppress or fail to elicit the JA/ET signal transduction pathway.
Project description:Disease resistance is mediated by specific recognition of pathogen avriulence effectors (AVR) by nucleotide-binding leucine-rich repeat (NLR) receptors. The barley (Hordeum vulgare) mildew locus A (mla) resistance gene homolog 1 (RGH1) encoded NLRs (MLAs) confer isolate-specific resistance to the widespread mildew fungus Blumeria graminis forma specialis hordei (Bgh). In barley, MLA has been subject to extensive functional diversification, resulting in allelic resistance specificities, each recognizing a cognate Bgh AVRa. The by genetic association isolated AVRa1 and AVRa13 effectors belong to the candidate secreted effector protein (CSEP) gene family (Lu et al., 2016). To unravel the complex mechanisms underlying MLA functional diversification in barley and wheat, isolation of numerous Bgh AVRa genes and recognition of their gene products by MLA is necessary. Our here deployed higher resolution genetic association approach identified the Bgh avirulence gene candidate loci AVRa7, AVRa9, AVRa22 and AVRa10 by associating of transcript polymorphisms and AVRa phenotypes from a collection of 27 Bgh isolates. We collected 10 Bgh isolates from a local Bgh population in Cologne in addition to our previous collection of 17 Bgh isolates (Lu et al., 2016).
