Project description:In order to explore the role of LaeA in secondary metabolite biosynthetic gene clusters’ regulation, toxin production, and virulence of Valsa mali, TMT-based proteomic analysis of wildtype, LaeA deletion mutant and overexpression mutant were performed. Totally, 4,299 proteins (FDR < 0.01) were identified by searching against the Valsa mali protein sequence database.
Project description:Dicer proteins are mainly responsible for generating small RNAs (sRNAs). In previous study, two DCL proteins in Valsa mali, the pathogenic fungus of apple tree Valsa canker, were found to be associated with the pathogenicity and generation of sRNAs. In this study, we constructed two milRNA libraries using the the wild-type 03-8 (MVm) and Vm-DCL2 deletion mutant (MD2) strains and the differential expression of miRNA-like RNAs (milRNAs) were analyzed based on the deep-sequencing of the wild-type and Vm-DCL2 mutant, respectively. In total, by comparing the expression difference of milRNAs between MVm and MD2, it was found that 33 milRNAs were not detected in MD2, 28 milRNAs were both detected in MVm and MD2. By statistical analysis, one and 17 milRNAs showed up-regulated and down-regulated expression in MD2 compared with MVm, respectively (p<0.05). Importantly, 10 milRNAs were not detected in MD2, and identified to be DCL2 dependent milRNAs. We also identified the target genes of these milRNAs using degradome sequencing technology and found they were associated with protein phosphatase, isocitrate dehydrogenase, phosphoglycerate mutase, etc. The study will lay a foundation for the comprehensive analysis of pathogenic mechanisms of V. mali, and enrich cognition of the generation and function of fungal sRNA.
Project description:miRNAs were important regulators involving in plant-pathogen interactions. However, their roles in apple response to Valsa canker pathogen (Valsa mali, Vm) infection were poorly understood. In this study, we constructed two miRNA libraries using the bark tissues of apple twig (Malus domestica Borkh “Fuji”) inoculated with Vm (IVm) and PDA medium (control, BMd). Among the all miRNAs, 23 miRNAs were specifically isolated in BMd and 39 miRNAs were specifically isolated in IVm. Compared with BMd, the expression of 294 miRNAs decreased, and 172 miRNAs increased in IVm, respectively. We also identified the target genes of these miRNAs using degradome sequencing technology. In total, 353 differentially expressed miRNAs during the pathogen infection were detected to target 1 077 unigenes with 2 251 cleavage sites. Based on GO and KEGG analysis, the genes were found to be mainly related to transcription regulation and signal transduction. We further selected 17 miRNAs and 22 corresponding target genes to detect the expression profiles during pathogen infection. The results indicate that most of them are involved in apple twig-Vm interaction. What’s more, miRNAs and their corresponding target genes seem to regulate the apple twig-Vm interaction by forming many complicated regulation networks. It is worth that a conserved miRNAs mdm-miR482b, which was down regulated in IVm compared with BMd, has 14 potential target genes, and most of them were disease resistance related genes. More important, the feedback regulation of sRNA pathway in apple twig was much more complex and critical in the interaction between apple bark tissue and V. mali. The results provide insights into the crucial functions of miRNAs in the woody plant, apple tree-Vm interaction.
Project description:MicroRNAs (miRNAs) play important roles by regulating the expression of target genes in plant and animal. However, little known about mechanism of fungal miRNA-like RNAs (milRNAs) regulating target gene restricts their functional exploration. In this study, multiple omics were used to identify the milRNAs and their target genes in a phytopathogenic fungus Valsa mali. Many candidate pathogenic factors were found to be regulated by milRNA-directed cleavage way. Absence or downregulated expression of Vm-milRNAs promote expression of candidate pathogenic factors during V. mali infection. Vm-milR16 is a significantly downregulated milRNA during V. mali infection, resulting in significantly upregulated expression of three target genes: VmSNF1, VmDODA, and VmHy1. Overexpression of Vm-milR16 significantly reduces the pathogenicity of V. mali. And all the three target genes of Vm-milR16 are required for the full pathogenicity of V. mali. Further analysis revealed that VmSNF1 regulates the pathogenicity by affecting the expression of pectinase genes during V. mali infection. And all the three target genes are essential for oxidative stress response during V. mali-host interaction. Vm-milRNAs may help V. mali to intelligently use limited resources and adaptively regulate pathogenicity by enhancing expression of pathogenic factors and fitness during infection.