Castro Bardo, Baik Suji, Tran Megann, Zhu Jie, Li Tianrun, Tang Andrea, Aoun Nathalie, Blundell Alison C, Gomez Michael, Zhang Elaine, Cho Myeong-Je, Lowe-Power Tiffany, Siddique Shahid, Staskawicz Brian, Coaker Gitta
Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA.
Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA.
Plant Cell. 2025 May 9;37(5). doi: 10.1093/plcell/koaf049.
Reactive oxygen species (ROS) accumulation is required for effective plant defense. Accumulation of the Arabidopsis (Arabidopsis thaliana) NADPH oxidase respiratory burst oxidase homolog D (RBOHD) is regulated by phosphorylation of a conserved C-terminal residue (T912) leading to ubiquitination by the RING E3 ligase Pbl13-interacting RING domain E3 ligase (PIRE). Arabidopsis PIRE knockouts exhibit enhanced ROS production and resistance to the foliar pathogen Pseudomonas syringae. Here, we identified 170 PIRE homologs, which emerged in tracheophytes and expanded in angiosperms. We investigated the role of tomato (Solanum lycopersicum) PIRE homologs in regulating ROS production, RBOH stability, and disease resistance. Mutational analyses of residues corresponding to T912 in the tomato RBOHD ortholog, SlRBOHB, affected protein accumulation and ROS production in a PIRE-dependent manner. Using genome editing, we generated mutants in 2 S. lycopersicum PIRE (SlPIRE) homologs. SlPIRE1 edited lines (Slpire1) in the tomato cultivar M82 displayed enhanced ROS production upon treatment with flg22, an immunogenic epitope of flagellin. Furthermore, Slpire1 exhibited decreased disease symptoms and bacterial accumulation when inoculated with foliar bacterial pathogens P. syringae and Xanthomonas campestris. However, Slpire1 exhibited similar levels of colonization as wild type upon inoculation with diverse soil-borne pathogens. These results indicate that PIRE regulates RBOHs in multiple plant species and is a promising target for foliar disease control. This study also highlights the pathogen-specific role of PIRE, indicating its potential for targeted manipulation to enhance foliar disease resistance without affecting root-associated pathogenic interactions.
活性氧（ROS）积累是植物有效防御所必需的。拟南芥（Arabidopsis thaliana）NADPH氧化酶呼吸爆发氧化酶同源物D（RBOHD）的积累受保守C末端残基（T912）磷酸化的调控，导致被RING E3连接酶Pbl13相互作用RING结构域E3连接酶（PIRE）泛素化。拟南芥PIRE基因敲除植株表现出增强的ROS产生以及对叶部病原菌丁香假单胞菌（Pseudomonas syringae）的抗性。在此，我们鉴定出170个PIRE同源物，它们出现在维管植物中并在被子植物中扩增。我们研究了番茄（Solanum lycopersicum）PIRE同源物在调节ROS产生、RBOH稳定性和抗病性方面的作用。对番茄RBOHD直系同源基因SlRBOHB中与T912相对应的残基进行突变分析，以PIRE依赖的方式影响蛋白质积累和ROS产生。利用基因组编辑技术，我们在2个番茄PIRE（SlPIRE）同源物中产生了突变体。番茄品种M82中的SlPIRE1编辑株系（Slpire1）在用鞭毛蛋白的免疫原性表位flg22处理后表现出增强的ROS产生。此外，Slpire1在接种叶部细菌病原菌丁香假单胞菌和野油菜黄单胞菌（Xanthomonas campestris）时表现出减轻的病害症状和细菌积累。然而，Slpire1在接种多种土传病原菌时表现出与野生型相似的定殖水平。这些结果表明PIRE在多种植物物种中调节RBOH，是叶部病害防治的一个有前景的靶点。本研究还突出了PIRE在病原体特异性方面的作用，表明其在不影响与根相关的致病相互作用的情况下进行靶向操作以增强叶部抗病性的潜力。
