Colletotrichum scovillei, a member of the Colletotrichum acutatum species complex, causes severe anthracnose of pepper fruit, reducing yield and quality. However, the molecular mechanisms underlying its pathogenesis are unknown. Ste7 kinase in the Fus3/Kss1-related mitogen protein kinase signaling pathway plays an important role in plant infection by phytopathogenic fungi. In this study, the function of CsSTE7, an ortholog of Ste7, was investigated in C. scovillei using a targeted gene deletion mutant (ΔCsste7). Compared to the wild type, ΔCsste7 had normal mycelial growth, but conidial morphology, germination of conidia, and tolerance to cell wall integrity and osmotic stresses were defective. Importantly, ΔCsste7 was completely defective in appressorium formation and causing anthracnose on pepper fruits. These defects were restored in the complemented strain (Csste7c). The results suggest that CsSTE7 is essential for development and pathogenicity of C. scovillei.

斯科维尔炭疽菌 (Colletotrichum scovillei ) 是尖头炭疽菌(Colletotrichum acutatum)物种复合体的成员，会引起辣椒果实严重炭疽病，降低产量和品质。然而，其发病机制的分子机制尚不清楚。 Fus3/Kss1相关丝裂原蛋白激酶信号通路中的Ste7激酶在植物病原真菌感染植物中发挥重要作用。在本研究中，使用靶向基因缺失突变体 ( ΔCsste7 ) 在C. scovillei中研究了Ste7的直系同源物CsSTE7的功能。与野生型相比，ΔCsste7菌丝生长正常，但分生孢子形态、分生孢子萌发以及对细胞壁完整性和渗透胁迫的耐受性有缺陷。重要的是，ΔCsste7在附着胞形成方面完全有缺陷，并导致辣椒果实炭疽病。这些缺陷在补充菌株（Csste7c）中得到了恢复。结果表明，CsSTE7对于C. scovillei的发育和致病性至关重要。