近年孢子丝菌病的发病率逐年攀升，其病原菌致病性的形成机制尚未明确。孢子丝菌由菌丝相向酵母相的形态转化过程是其致病性形成的关键所在。孢子丝菌通过双组分信号系统识别环境信号，再激活丝裂原活化蛋白激酶（MAPK）信号通路，进而调控酵母相特异性基因及毒力相关等基因的表达。但有关孢子丝菌MAPK通路激活的详细机制所知甚少。我们前期利用比较蛋白组学方法鉴定出Ste-20激酶为孢子丝菌酵母相特异表达蛋白，而Ste-20激酶在酿酒酵母中被证明可以激活MAPK通路。我们推测Ste-20在孢子丝菌的双相转换和致病性形成中具有重要作用。本课题拟采用前期建立的根癌农杆菌介导的小分子双链RNA干扰技术构建Ste-20基因沉默菌株，比较基因干扰株与野生株的差异，探明Ste-20激酶在孢子丝菌双相转换和致病性形成中的作用及机制。本课题的执行，可以加深对孢子丝菌病发病机制的认识，为孢子丝菌病提供新的治疗策略。

The incidence of sporotrichosis was increased in recent years, but the mechanisms of its pathogenicity still remain unclear. The phase inversion process of Sporothrix schenckii from the mycelial to the yeast phase is the key of its pathogenicity. The Sporothrix schenckii to sense and respond to environmental signals by two-component signaling systems, then activating the mitogen-activated protein kinase (MAPK) pathway that in turn regulates the yeast phase transformation and virulence gene expression. However, the mechanisms of MAPK pathway activation in Sporothrix schenckii are not very clear. Our previous studies demonstrated that the Ste-20 kinase is a yeast phase-specific protein in Sporothrix schenckii by comparative proteomics. The Ste-20 kinase has been proved to activate the MAPK pathway in Saccharomyces cerevisiae. Our results suggest that Ste-20 kinase may play an important role in the two-phase conversion and pathogenicity of Sporothrix schenckii. In this project, we will further elucidate the role and mechanism of Ste-20 kinase relulates the duplex conversion and pathogenicity in Sporothrix schenckii by our pre-established RNA interference technology which mediated by Agrobacterium tumefaciens. This study may benefit us in understanding the pathogenesis of sporotrichosis and provide novel therapeutic strategies.