Project description:Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease.
Project description:Epigenetic processes play a crucial role in the regulation of plant stress responses, but their role in plant-pathogen interactions remains poorly understood. Although histone modifying enzymes are deregulated in galls induced by root-knot nematode (RKN, Meloidogyne graminicola) in rice, their influence on plant defence and their genome-wide impact has not been comprehensively investigated. At genome-wide level, three histone marks, H3K9ac, H3K9me2 and H3K27me3 were studied by chromatin-immunoprecipitation (ChIP)-sequencing on RKN-induced galls at 3 days post inoculation. While levels of H3K9ac and H3K27me3 were strongly enriched, H3K9me2 was generally depleted in galls versus control root tips. Differential histone peaks were generally associated with plant defence related genes. Total RNA sequencing was performed to assess the effect of histone modification changes on gene expression.
Project description:This study employed label-free quantitative mass spectrometry to investigate the proteomic changes in roots of the susceptible rice cultivar Nipponbare during a compatible interaction with the root-knot nematode Meloidogyne graminicola. Root samples were collected at four time points: before inoculation (0 dpi), and at 1, 3, and 7 days post-inoculation (dpi). For time points where galls were visible (3 and 7 dpi), root sections containing galls were specifically collected. Three biological replicates were analyzed for each condition. In total, 6,072 proteins were identified. Comparative analysis between infected and uninfected roots identified 513 proteins uniquely regulated in response to nematode infection. Bioinformatic analyses (GO, KEGG) of these proteins highlighted significant enrichment in defense-related pathways, including phenylpropanoid biosynthesis, glutathione metabolism, and alpha-linolenic acid metabolism. Key downregulated defense-related proteins were further validated, and their corresponding gene expression was analyzed in a resistant rice accession.
Project description:Ascorbic acid (AA) is known to play a vital role in plant growth and detoxification of reactive oxygen species, however little is known about the significance of AA oxidation in plant defence against pathogens. • The role of ascorbate oxidation in rice defence against root-knot nematodes, Meloidogyne graminicola, was tested with application of AA, ascorbate oxidase (AO), dehydroascorbic acid (DHA), biosynthesis inhibitors and use of mutants. Transcriptome analysis was done on AO treated plants, and hormone measurements were executed to confirm the results. Biochemical analyses were used to study oxidative stress markers, including accumulation of H2O2, , malondialdehyde and AA/DHA.
