State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing 100193, China.
International Maize and Wheat Improvement Center (CIMMYT), ICRAF Campus, Gigiri, Nairobi, Kenya.
Plant Physiol. 2022 Jun 1;189(2):1065-1082. doi: 10.1093/plphys/kiac099.
Maize chlorotic mottle virus (MCMV) is the key pathogen causing maize lethal necrosis (MLN). Due to the sharply increased incidence of MLN in many countries, there is an urgent need to identify resistant lines and uncover the underlying resistance mechanism. Here, we showed that the abundance of maize (Zea mays) microR167 (Zma-miR167) positively modulates the degree of resistance to MCMV. Zma-miR167 directly targets Auxin Response Factor3 (ZmARF3) and ZmARF30, both of which negatively regulate resistance to MCMV. RNA-sequencing coupled with gene expression assays revealed that both ZmARF3 and ZmARF30 directly bind the promoter of Polyamine Oxidase 1 (ZmPAO1) and activate its expression. Knockdown or inhibition of enzymatic activity of ZmPAO1 suppressed MCMV infection. Nevertheless, MCMV-encoded p31 protein directly targets ZmPAO1 and enhances the enzyme activity to counteract Zma-miR167-mediated defense to some degree. We uncovered a role of the Zma-miR167-ZmARF3/30 module for restricting MCMV infection by regulating ZmPAO1 expression, while MCMV employs p31 to counteract this defense.
玉米褪绿斑驳病毒（MCMV）是导致玉米坏死性猝死（MLN）的关键病原体。由于许多国家 MLN 的发病率急剧上升，因此迫切需要鉴定抗性品系并揭示其潜在的抗性机制。在这里，我们表明玉米（Zea mays）microR167（Zma-miR167）的丰度正向调节对 MCMV 的抗性程度。Zma-miR167 直接靶向生长素反应因子 3（ZmARF3）和 ZmARF30，两者均负调控对 MCMV 的抗性。RNA 测序结合基因表达分析表明，ZmARF3 和 ZmARF30 均可直接结合多胺氧化酶 1（ZmPAO1）启动子并激活其表达。ZmPAO1 的敲低或抑制其酶活性可抑制 MCMV 感染。然而，MCMV 编码的 p31 蛋白可直接靶向 ZmPAO1 并增强酶活性，从而在一定程度上抵消 Zma-miR167 介导的防御。我们揭示了 Zma-miR167-ZmARF3/30 模块通过调节 ZmPAO1 表达来限制 MCMV 感染的作用，而 MCMV 则利用 p31 来对抗这种防御。
