Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agriculture and Biotechnology, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou 310058, China.
Centre of Analysis and Measurement, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou 310058, China.
Int J Mol Sci. 2022 Jun 14;23(12):6622. doi: 10.3390/ijms23126622.
The plant-specific ASR (abscisic acid, stress and ripening) transcription factors are pivotal regulators of plant responses to abiotic stresses. However, their functions in plant disease resistance remain largely unknown. In this study, we revealed the role of OsASR6 in rice plants’ resistance to two important bacterial diseases caused by Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) and elucidated the mechanisms underlying OsASR6-regulated resistance. The expression of OsASR6 was strongly elevated in response to both Xoo and Xoc challenges. Silencing of OsASR6 in OsASR6-RNAi transgenic plants markedly enhanced rice resistance to the two bacterial pathogens. Moreover, comparative transcriptome analyses for OsASR6-RNAi and wild-type plants inoculated and uninoculated with Xoc demonstrated that OsASR6 suppressed rice resistance to Xoc by comprehensively fine-tuning CIPK15- and WRKY45-1-mediated immunity, SA signaling and redox homeostasis. Further luciferase reporter assays confirmed that OsASR6 negatively regulated CIPK15 but not WRKY45-1 expression in planta. Overexpression of OsCIPK15 strongly enhanced rice resistance to Xoo and Xoc. Collectively, these results reveal that OsASR6 alleviates rice resistance through the transcriptional suppression of OsCIPK15, and thus links calcium signaling to rice resistance against X. oryzae. Our findings provide insight into the mechanisms underlying OsASR6-mediated regulation of rice resistance to X. oryzae.
植物特异性 ASR（脱落酸、胁迫和成熟）转录因子是植物对非生物胁迫反应的关键调节因子。然而，它们在植物抗病性中的作用在很大程度上仍然未知。在这项研究中，我们揭示了 OsASR6 在水稻植株对由稻黄单胞菌 pv. 引起的两种重要细菌性疾病的抗性中的作用oryzae (Xoo) 和 X. oryzae pv. oryzicola (Xoc)，并阐明了 OsASR6 调节抗性的机制。OsASR6 的表达在响应 Xoo 和 Xoc 挑战时强烈上调。在 OsASR6-RNAi 转基因植物中沉默 OsASR6 显着增强了水稻对两种细菌病原体的抗性。此外，对 OsASR6-RNAi 和未接种和接种 Xoc 的野生型植物进行比较转录组分析表明，OsASR6 通过全面精细调节 CIPK15 和 WRKY45-1 介导的免疫、SA 信号和氧化还原稳态来抑制水稻对 Xoc 的抗性。进一步的荧光素酶报告基因测定证实，OsASR6 在体内负调控 CIPK15 但不调控 WRKY45-1 的表达。OsCIPK15 的过表达强烈增强了水稻对 Xoo 和 Xoc 的抗性。总之，这些结果表明，OsASR6 通过转录抑制 OsCIPK15 来减轻水稻的抗性，从而将钙信号与水稻对稻黄单胞菌的抗性联系起来。我们的研究结果为 OsASR6 介导的水稻对稻黄单胞菌抗性调控的机制提供了新的认识。
