板栗疫病菌RasGAP基因的功能研究

Functional Study of RasGAP Gene in Chestnut Blight Fungus

Ras超家族蛋白的生化功能是催化GTP的水解,为生命体提供能量。RasGAP是Ras蛋白激活子,可提高Ras蛋白对GTP的水解能力。本研究利用同源双交换的方法成功构建了板栗疫病菌RasGAP基因的缺失突变株ΔRasGAP。与野生型菌株EP155及敲除出发菌株Δcpku80相比,ΔRasGAP突变体的菌丝形态、漆酶分泌、致病力和对低毒病毒复制的支持均无明显变化。但ΔRasGAP的生长速度加快,色素分泌延迟,分生孢子产量也显著下降。mRNA定量分析表明,RasGAP基因的缺失导致产孢相关基因的转录模式发生明显改变,提示RasGAP是板栗疫病菌分生孢子形成的一个重要调控因子。本研究为揭示板栗疫病菌产孢机制提供了新的知识。

The Ras superfamily protein provides energy to the living body by catalyzing the hydrolysis of GTP.RasGAP is a Ras protein activator,which can enhance the hydrolytic capacity of Ras protein.In this study,the C.parasitica RasGAP gene deletion strainΔRasGAP was constructed successfully by homologous recombination.Compared to the wild strain EP155 and the knock-out original strainΔcpku80,the mycelial morphology,laccase secretion,virulence and virus accumulation of RasGAP null mutant did not obviously change.However,theΔRasGAP mutants showed a phenotype of faster growth rate,delayed orange pigmentation and lower level of sporulation.Besides,transcriptional analysis showed that deletion of RasGAP influenced the transcript accumulation level of four sporulation-related genes,indicating that RasGAP is an important regulatory factor for the formation of conidia of C.parasitica.This work provides a novel knowledge for further studying mechanisms of the sporulation in C.parasitica.