促生解淀粉芽胞杆菌SQR9 定殖对黄瓜根系 基因表达的转录组学研究.

Abstract:[Objectives]The objective of this study was to illustrate the plant growth-promoting mechanisms in terms of the response of plants to rhizosphere beneficial microbes, based on the transcriptional profiling of cucumber root genes responsive to the inoculation of plant growth-promoting rhizobacterium Bacillus amyloliquefaciens SQR9. [Methods]The transcriptional response of cucumber root genes to B,, amyloliquefaciens SQR9 was analyzed by Illumina high, throughput transcriptome sequencing, the significant differentially expressed genes were further examined by gene ontology(GO) and Kyoto encyclopedia of genes and genomes(KEGG) analysis. [Results]As compared with the non, inoculated control, 484 genes were detected to be significantly differentially expressed after the inoculation of strain SQR9, including 300 up, regulated genes and 184 down, regulated genes. Real, time PCR validation showed that the expression patterns of the selected genes were in accordance with the results of transcriptional profiling analysis, suggesting that the transcriptome data were reliable. The differentially expressed genes in response to strain SQR9 were mainly involved in carbohydrate metabolism, amino acid metabolism, biosynthesis of other secondary metabolites, and signal transduction. With regards to the genes related to plant growth, promotion, ASP1 that encodes for an aspartate transaminase was activated by strain SQR9 and was up, regulated by approximately 4 times, the expression of PDC encoding for pyruvate decarboxylase in glycolysis(EMP pathway), as well as FBA6 encoding for fructose, bisphosphate aldolase in Calvin cycle, were both up, regulated by 3- 5 times in the inoculated treatment as compared with the control, in the IAA, responsive pathway, IAA8 that encodes for a repressor, was down, regulated by strain SQR9, while SAUR77 and SAUR21 encoding the responsive proteins, were up, regulated by approximately 3 times, suggesting that the exogenous indole, 3, acetic acid(IAA)stimulated the endogenesis IAA, pathway in plants. In regard to plant immunity, the inoculation of strain SQR9 increased the expression of WRKY29 and ERF1B encoding for transcription factors involved in immune signaling pathway, which could induce the host systemic resistance and enhance the disease resistance, moreover, genes encodes for stress resistance factor C4 H and ADH1, were significantly activated by inoculation. [Conclusions] PGPR strain SQR9 promotes cucumber plants growth and enhances disease resistance through activation of genes involved in metabolism and immune pathway. [ABSTRACT FROM AUTHOR]