Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Shanghai, 200032, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
New Phytol. 2020 Jan;225(1):474-487. doi: 10.1111/nph.16111. Epub 2019 Sep 25.
Ethylene (ET) and jasmonic acid (JA) play important roles in plant defenses against biotic stresses. Crosstalk between JA and ET has been well studied in mediating pathogen resistance, but its roles in piercing-sucking insect resistance are unclear. The brown planthopper (BPH; Nilaparvata lugens) is the most notorious piercing-sucking insect specific to rice (Oryza sativa) that severely affects yield. A genetic analysis revealed that OsEBF1 and OsEIL1, which are in the ET signaling pathway, positively and negatively regulated BPH resistance, respectively. Molecular and biochemical analyses revealed direct interactions between OsEBF1 and OsEIL1. OsEBF1, an E3 ligase, mediated the degradation of OsEIL1 through the ubiquitination pathway, indicating the negative regulation of the ET-signaling pathway in response to BPH infestation. An RNA sequencing analysis revealed that a JA biosynthetic pathway-related gene, OsLOX9, was downregulated significantly in the oseil1 mutant. Biochemical analyses, including yeast one-hybrid, dual luciferase, and electrophoretic mobility shift assay, confirmed the direct regulation of OsLOX9 by OsEIL1. This study revealed the synergistic and negative regulation of JA and ET pathways in response to piercing-sucking insect attack. The synergistic mechanism was realized by transcriptional regulation of OsEIL1 on OsLOX9. OsEIL1-OsLOX9 is a novel crosstalk site in these two phytohormone signaling pathways.
乙烯 (ET) 和茉莉酸 (JA) 在植物抵御生物胁迫方面发挥着重要作用。JA 和 ET 之间的串扰在介导病原体抗性方面已经得到了很好的研究，但在刺吸式昆虫抗性中的作用尚不清楚。褐飞虱 (BPH; Nilaparvata lugens) 是最臭名昭著的专门侵害水稻 (Oryza sativa) 的刺吸式昆虫，严重影响产量。遗传分析表明，ET 信号通路中的 OsEBF1 和 OsEIL1 分别正向和负向调控 BPH 抗性。分子和生化分析揭示了 OsEBF1 和 OsEIL1 之间的直接相互作用。作为 E3 连接酶的 OsEBF1 通过泛素化途径介导 OsEIL1 的降解，表明 ET 信号通路对 BPH 侵害的负调控。RNA 测序分析显示，JA 生物合成途径相关基因 OsLOX9 在 oseil1 突变体中显著下调。酵母单杂交、双荧光素酶和电泳迁移率变动分析等生化分析证实了 OsEIL1 对 OsLOX9 的直接调控。这项研究揭示了 JA 和 ET 途径在应对刺吸式昆虫攻击时的协同和负向调节。协同机制是通过 OsEIL1 对 OsLOX9 的转录调控来实现的。OsEIL1-OsLOX9 是这两种植物激素信号通路中的一个新的串扰位点。
