The bacterial effector AvrRxo1 inhibits vitamin B6 biosynthesis to promote infection in rice.

Haifeng Liu, Chongchong Lu, Yang Li, Tao Wu, Baogang Zhang, Baoyou Liu, Wenjie Feng, Qian Xu, Hansong Dong, Shengyang He, Zhaohui Chu, Xinhua Ding

Plant communications 2022 May 09

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Xanthomonas oryzae pv. oryzicola (Xoc), which causes rice bacterial leaf streak, invades leaves mainly through stomata, which are often closed as a plant immune response against pathogen invasion. How Xoc overcomes stomatal immunity is unclear. Here, we show that the effector protein AvrRxo1, an ATP-dependent protease, enhances Xoc virulence and inhibits stomatal immunity by targeting and degrading rice OsPDX1 (pyridoxal phosphate synthase), thereby reducing vitamin B6 (VB6) levels in rice. VB6 is required for the activity of aldehyde oxidase, which catalyzes the last step of abscisic acid (ABA) biosynthesis, and ABA positively regulates rice stomatal immunity against Xoc. Thus, we provide evidence supporting a model in which a major bacterial pathogen inhibits plant stomatal immunity by directly targeting VB6 biosynthesis and consequently inhibiting the biosynthesis of ABA in guard cells to open stomata. Moreover, AvrRxo1-mediated VB6 targeting also explains the poor nutritional quality, including low VB6 levels, of Xoc-infected rice grains. Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.

Citation

Haifeng Liu, Chongchong Lu, Yang Li, Tao Wu, Baogang Zhang, Baoyou Liu, Wenjie Feng, Qian Xu, Hansong Dong, Shengyang He, Zhaohui Chu, Xinhua Ding. The bacterial effector AvrRxo1 inhibits vitamin B6 biosynthesis to promote infection in rice. Plant communications. 2022 May 09;3(3):100324