Wheat (Triticum aestivum L.) is an important staple crop for global human. The necrotrophic fungus Rhizoctonia cerealis is the causal pathogen of sharp eyespot, a devastating disease of wheat. Herein, we identified RcMEP1, a zinc metalloproteaseencoding gene from R. cerealis genomic sequences, and characterized its pathogenesis function. RcMEP1 expressed at markedly-high levels during R. cerealis infection process to wheat. The predicted protein RcMEP1 comprises of 287 amino acid residues and contains a signal peptide and a M43 metalloprotease domain harboring the active site motif (HEVGHWLGLYH). The assays of Agrobacterium tumefaciens-mediated transient expression in Nicotiana benthamiana leaves indicated that RcMEP1 is an apoplastic elicitor of cell death, and that the predicted signal peptide functions and is required for secretion and cell death-induction. The purified RcMEP1 protein and its M43 domain peptide were individually able to induce plant cell death and H₂O₂ accumulation, and to inhibit expression of host chitinases when infiltrated into wheat and N. benthamiana leaves, while the M43 domain-deleting peptide and negative control lacked the capacity. Moreover, compared with the control pretreatment, the purified RcMEP1 protein or its M43-domain peptide resulted in enhanced pathogenesis in the inoculated wheat, whereas the M43 domain-deleting peptide failed. These results suggest that RcMEP1 acted as an important pathogenicity factor during R. cerealis infection to wheat and that its signal peptide and M43 domain are required for the secretion and pathogenesis of RcMEP1. This study provides insights into pathogenesis role of M43 domain-containing metalloproteases during R. cerealis infection to wheat.

小麦（Triticum aestivum L.）是全球人类的重要主粮。的死体营养真菌纹枯病是纹枯病的致病病原体，小麦的破坏性疾病。在本文中，我们确定RcMEP1，从锌metalloproteaseencoding基因R.禾谷基因组序列，并表征其发病机制的功能。RcMEP1在小麦感染谷物的过程中以高水平表达。预测的蛋白RcMEP1包含287个氨基酸残基，并包含一个信号肽和一个带有活性位点基序（HEVGHWLGLYH）的M43金属蛋白酶结构域。根癌农杆菌的测定烟草叶片中介导的瞬时表达表明，RcMEP1是细胞死亡的质外诱导剂，并且预测的信号肽起作用，并且是分泌和诱导细胞死亡的必需物质。纯化的RcMEP1蛋白及其M43结构域肽分别能够诱导植物细胞死亡和H ₂ O ₂积累，并能渗入小麦和本氏烟草中并抑制宿主几丁质酶的表达。叶，而M43域删除肽和阴性对照缺乏能力。此外，与对照预处理相比，纯化的RcMEP1蛋白或其M43结构域肽导致接种小麦的发病机理增强，而M43结构域缺失肽失败。这些结果表明，RcMEP1在小麦感染谷物的过程中起着重要的致病性因子作用，其信号肽和M43结构域是RcMEP1分泌和发病所必需的。这项研究提供了洞察到麦角芽孢杆菌感染小麦过程中包含M43域的金属蛋白酶的发病机理的见解。