论文题目: Comparative study of Arabidopsis PBS1 and a wheat PBS1 homolog helps understand the mechanism of PBS1 functioning in innate immunity

论文编号:
作者: Jianhang Sun（孙建杭）, Guozhong Huang（黄国中）, Fenggui Fan（范锋贵）, Shuangfeng Wang（王双凤）, Yingying Zhang（张莹莹）,Yufang Han（韩玉芳）, Yanmin Zou（邹艳敏）, Dongping Lu（吕东平）
刊物名称: Scientific Reports
卷期页码: 7, (1), 5487
发表年度: 2017
DOI: http://doi.org/10.1038/s41598-017-05904-x
摘要:

Arabidopsis AVRPPHB SUSCEPTIBLE1 (PBS1) serves as a "decoy" in activating RESISTANCE TO PSEUDOMONAS SYRINGAE5 (RPS5) upon cleavage by Pseudomonas phaseolicola B (AvrPphB), a Pseudomonas syringae effector. The SEMPH motif in PBS1 was thought to allow it to be distinguished by RPS5 from the closely related Arabidopsis kinases. However, the underlying mechanism is not fully understood. Here, we isolated and characterized a wheat PBS1 homolog, TaPBS1. Although this plasma membrane-localized kinase could be cleaved by AvrPphB and could associate with RPS5, it failed to trigger RPS5-mediated hypersensitive response (HR) in a transient assay. TaPBS1 harbors a STRPH motif. The association of RPS5 with TaPBS1 was weaker than with PBS1. Change of the STRPH motif to the SEMPH motif allowed TaPBS1 to trigger HR. However, the SEMPH motif is not required for association of PBS1 with RPS5. The difference between "SEMPH" and "STRPH" points to the importance of "EM" in PBS1. Furthermore we found that a negatively charged amino acid at the position of "E" in the SEMPH motif was required for recognition of PBS1 by RPS5. Additionally, both PBS1 and TaPBS1 undergo the flagellin-induced phosphorylation. Therefore, our work will help understand the mechanism of PBS1 functioning in plant innate immunity.