Wang Chenyang, Zheng Yaning, Liu Zhishan, Qian Yongpan, Li Yue, Yang Limei, Liu Sihui, Liang Wenxing, Li Jingtao
College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao, China.
College of Science and Information, Qingdao Agricultural University, Qingdao, China.
Front Microbiol. 2023 Jan 25;14:1103418. doi: 10.3389/fmicb.2023.1103418. eCollection 2023.
Pathogens utilize secretory effectors to manipulate plant defense. f. sp. () is the causal agent of wilt disease in tomatoes. We previously identified 32 secreted effector candidates by LC-MS analysis. In this study, we functionally identified one of the secreted proteins, FolAsp, which belongs to the aspartic proteases (Asp) family. The FolAsp was upregulated with host root specifically induction. Its N-terminal 1-19 amino acids performed the secretion activity in the yeast system, which supported its secretion in . Phenotypically, the growth and conidia production of the deletion mutants were not changed; however, the mutants displayed significantly reduced virulence to the host tomato. Further study revealed the FolAsp was localized at the apoplast and inhibited INF1-induced cell death . Meanwhile, FolAsp could inhibit flg22-mediated ROS burst. Furthermore, FolAsp displayed protease activity on host protein, and overexpression of FolAsp in enhanced pathogen virulence. These results considerably extend our understanding of pathogens utilizing secreted protease to inhibit plant defense and promote its virulence, which provides potential applications for tomato improvement against disease as the new drug target.
病原体利用分泌效应子来操控植物防御。番茄枯萎病菌（Fusarium oxysporum f. sp. lycopersici）是番茄枯萎病的致病因子。我们之前通过液相色谱-质谱分析鉴定出32个分泌效应子候选物。在本研究中，我们对其中一种分泌蛋白FolAsp进行了功能鉴定，它属于天冬氨酸蛋白酶（Asp）家族。FolAsp在宿主根部特异性诱导下上调表达。其N端的1 - 19个氨基酸在酵母系统中具有分泌活性，这支持了它在番茄枯萎病菌中的分泌。从表型上看，番茄枯萎病菌缺失突变体的生长和分生孢子产生没有变化；然而，这些突变体对宿主番茄的毒力显著降低。进一步研究表明，FolAsp定位于质外体并抑制INF1诱导的细胞死亡。同时，FolAsp能抑制flg22介导的活性氧爆发。此外，FolAsp对宿主蛋白具有蛋白酶活性，在番茄枯萎病菌中过表达FolAsp可增强病原体的毒力。这些结果极大地扩展了我们对病原体利用分泌蛋白酶抑制植物防御并促进其毒力的理解，为作为新药物靶点的番茄抗病改良提供了潜在应用。
