尖孢镰刀菌HG-11响应解淀粉芽胞杆菌B501胁迫的机制分析

Mechanism Analysis of Fusarium oxysporum HG-11 Responses to Biocontrol Agent Bacillus amyloliquefaciens B501

前期研究发现生防拮抗菌解淀粉芽胞杆菌(Bacillus amyloliquefaciens)B501能够显著抑制尖孢镰刀菌(Fusarium oxysporum)HG-11,检测发现B501可以形成生物膜,具备产生纤维素酶和淀粉酶的能力。目前生物防治主要着眼于生防微生物的抑菌机制,而病原菌如何应对生防微生物胁迫的机制却常被忽略,因此旨在利用RNA-seq技术研究HG-11对B501生防胁迫响应的分子机制。结果表明,与对照HG-11样品相比,B501发酵液处理的HG-11样品中共有3171个基因显著差异表达,其中2106个基因上调表达,1065个基因下调表达。上调表达有与细胞壁和细胞膜结构相关的基因如甾醇3-β-葡萄糖基转移酶基因、脂肪酸合成酶基因等,与抗氧化相关的上调表达基因有氧化物酶基因、P-P-键-水解驱动的跨膜转运蛋白基因等,以及与核糖体和线粒体相关的上调表达基因,如核糖体蛋白复合物、异柠檬酸脱氢酶等基因;下调表达的酰基转移酶基因、DNA连接酶基因等均为与细胞修复相关的基因。推测B501的抗菌物质通过破坏细胞壁及细胞膜的结构,并进入细胞内部破坏核糖体和线粒体从而抑制真菌生长。而HG-11通过调节与此相关的多个靶标蛋白或合成途径的基因表达,以缓解B501的生防胁迫作用。初步明确了尖孢镰刀菌应对生防解淀粉芽胞杆菌胁迫的基因表达差异,病原菌的自我防御机制或许是生防菌株易变表现的一个重要因素,提高了对病原菌与生防菌互作结构的认识。

In previous studies,it was found that Fusarium oxysporum HG-11 was significantly inhibited by Bacillus amyloliquefaciens B501 which had the ability to form biofilm,produce amylase and cellulase.At present,the research of biological control mainly focuses on the antibacterial mechanism of biocontrol microorganisms to pathogens,but the mechanism of pathogens response to the stress of biocontrol microorganisms is often ignored.The RNA-seq technology was used to study the molecular mechanism of HG-11 responses to biological stress of B501.The results showed that 3171 genes were deferentially expressed in HG-11 treated with B501 comparing with the control HG-11,in which 2106 genes were up-regulated and 1065 were down-regulated,the up-regulated expression genes related to the fungal cell wall,were sterol 3-β-glucosyltransferase gene,fatty acid synthetase gene,etc.,the up-regulated expression genes related to the antioxidant system were oxidase gene,p-p-bond-hydrolysis-driven transmembrane transporter gene,etc.,and up-regulated expression genes related to ribosome and mitochondria were ribosome protein complex gene and isocitrate dehydrogenase gene,etc.In contrast,acyltransferase gene and DNA ligase generelated to cell repair were significantly down-regulated.It is suggested that the antibacterial substances of B501 can inhibit the growth of fungi by destroying the structure of cell wall and cell membrane,and damaging ribosome and mitochondria in cell interior.However,HG-11 can alleviate the biological stress of B501 by regulating the gene expression of multiple target proteins or synthetic pathways.The self-defense mechanism of pathogenic fungi may be an important factor in the variable performance of biocontrol strains.This study may improve the understanding in the interaction mechanism of pathogen and biocontrol bacteria.