State Key Laboratory for Crop Genetics & Germplasm Enhancement, Jiangsu Provincial Center of Plant Gene Engineering, Nanjing Agricultural University, Weigang, Nanjing, China.
Institute of Crop Science, the National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China.
J Exp Bot. 2018 Aug 14;69(18):4433-4442. doi: 10.1093/jxb/ery223.
Improved knowledge of the interactions between plants and insects will facilitate better insect control in crops. Brassinosteroids (BRs) play a vital role in plant growth, developmental processes, and responses to pathogen infection, but the role of BRs in interactions between plants and insects remain largely unknown. In this study, we characterized a negative role of BRs in rice defense against brown planthopper (BPH, Nilaparvata lugens) and examined its underlying mechanisms. We found that BPH infestation suppressed the BR pathway while successively activating the salicylic acid (SA) and jasmonic acid (JA) pathways. In addition, BR-overproducing mutants and plants treated with 24-epibrassinolide (BL) showed increased susceptibility to BPH, whereas BR-deficient mutants were more resistant than the wild-type. BRs down-regulated the expression of genes related to the SA pathway and reduced SA content while genes related to the JA pathway were up-regulated and JA content increased after BPH infestation. Furthermore, BR-mediated suppression of the SA pathway was impaired both in JA-deficient and JA-insensitive mutants. Our results demonstrate that BRs promote the susceptibility of rice plants to BPH by modulating the SA and JA pathways.
提高对植物与昆虫相互作用的认识将有助于更好地控制作物中的昆虫。油菜素内酯（BRs）在植物生长、发育过程以及对病原体感染的反应中起着至关重要的作用，但 BRs 在植物与昆虫相互作用中的作用在很大程度上仍不清楚。在这项研究中，我们描述了 BRs 在水稻抵御褐飞虱（BPH，Nilaparvata lugens）中的防御作用中的负调控作用，并研究了其潜在的机制。我们发现，褐飞虱取食抑制了 BR 途径，同时相继激活了水杨酸（SA）和茉莉酸（JA）途径。此外，BR 过量产生突变体和用 24-表油菜素内酯（BL）处理的植株对褐飞虱表现出更高的敏感性，而 BR 缺陷型突变体比野生型更具抗性。BRs 下调与 SA 途径相关的基因的表达并降低 SA 含量，而与 JA 途径相关的基因在褐飞虱取食后上调，JA 含量增加。此外，BR 介导的 SA 途径的抑制在 JA 缺陷型和 JA 不敏感突变体中均受到损害。我们的结果表明，BRs 通过调节 SA 和 JA 途径促进了水稻植株对褐飞虱的易感性。
