CsSSK1基因调控暹罗炭疽菌胁迫应答和致病性的功能分析

Functional Analysis of CsSSK1 Gene in Response to Stress Response and Virulence in Colletotrichum siamense

暹罗炭疽菌(Colletotrichum siamense)是热带、亚热带地区许多农林作物炭疽病的主要病原菌。SSK1是双组分系统中的应答调节蛋白,已有研究显示病原真菌中的SSK1与病原菌的形态建成、胁迫反应、耐药性和致病力有关,但在不同菌中其功能存在差异。为了解暹罗炭疽菌中同源基因CsSSK1的功能,本研究利用同源重组法构建了CsSSK1基因缺失突变体ΔCsSSK1和回补菌株ΔCsSSK1(CsSSK1),对其进行表型观察。结果显示:与野生型菌株相比,形态发育上,缺失突变体ΔCsSSK1的菌丝生长速率略有降低,分生孢子较短且产孢量低,孢子萌发率也降低;胁迫应答上,ΔCsSSK1显著提高了炭疽菌对NaCl、山梨醇、蔗糖、葡萄糖、刚果红胁迫的敏感性,提高了对氟康唑和戊唑醇的敏感性,但降低了对咯菌腈的敏感性;致病功能方面,CsSSK1基因缺失明显降低了致病力。研究结果表明CsSSK1基因参与调控暹罗炭疽菌的形态建成,应答盐胁迫、渗透胁迫、刚果红胁迫反应,参与药剂敏感性调控,影响暹罗炭疽菌的致病能力。本研究结果为深入了解暹罗炭疽菌CsSSK1基因功能,解析病原真菌应答胁迫反应的分子机理奠定基础。

Colletotrichum siamense is the main pathogen of anthracnose in many crops in tropical and subtropical regions.SSK1 is a response regulator protein of the two-component system.Studies have shown that SSK1 in pathogenic fungi is related to the morphogenesis,stress response,drug resistance and pathogenicity of pathogens,but SSK1 homologues have distinct functions in different fungi.In order to understand the function of CsSSK1 in C.siamense,the CsSSK1 gene deletion mutantΔCsSSK1 and the complement strainΔCsSSK1(CsSSK1)were constructed and phenotypically observed.The results showed that the deletion mutantΔCsSSK1 showed slightly retarded mycelial growth,shorter conidia,lower sporulation and conidial germination rate.ΔCsSSK1 significantly increased the sensitivity of C.siamense to NaCl,sorbitol,sucrose,glucose and Congo red,and the sensitivity to fluconazole and tebuconazole,but decreased the sensitivity to fludioxonil.The pathogenicity ofΔCsSSK1 was significantly reduced.The results showed that CsSSK1 gene was involved in the regulation of C.siamense morphogenesis,response to salt stress,osmotic stress,Congo red stress and fungicide stress,affecting the pathogenicity of C.siamense.The results would lay a foundation for further understanding the function of CsSSK1 gene in C.siamense and analyzing the molecular mechanism of pathogenic fungi response to stress.