Parasitic root-knot nematodes (RKNs) cause a severe reduction in crop yield and seriously threaten agricultural production. The phytohormones jasmonates (JAs) are important signals regulating resistance to multiple biotic and abiotic stresses. However, the molecular mechanism for JAs-regulated defense against RKNs in tomato remains largely unclear. In this study, we found that the transcription factor SlWRKY45 interacted with most JA-ZIM domain family proteins (JAZs), key repressors of the JA signaling. After infection by the RKN Meloidogyne incognita, the slwrky45 mutants exhibited lower gall numbers and egg numbers per gram of roots than wild type, whereas overexpression of SlWRKY45 attenuated resistance to M. incognita. Under M. incognita infection, the contents of jasmonic acid (JA) and JA-isoleucine (JA-Ile) in roots were repressed by SlWRKY45-overexpression. Furthermore, SlWRKY45 bound to and inhibited the promoter of the JA biosynthesis gene ALLENE OXIDE CYCLASE (AOC), and repressed its expression. Overall, our findings revealed that the SlJAZ-interaction protein SlWRKY45 attenuated RKN-regulated JA biosynthesis and repressed defense against the RKN M. incognita in tomato.

中文翻译：

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SlWRKY45 与 jasmonate-ZIM 结构域蛋白相互作用，负调控番茄根结线虫南方根结线虫的防御

寄生根结线虫（RKNs）导致作物产量严重下降，严重威胁农业生产。茉莉酸植物激素 (JAs) 是调节对多种生物和非生物胁迫抗性的重要信号。然而，JAs 调控的番茄中 RKNs 防御的分子机制仍不清楚。在这项研究中，我们发现转录因子 SlWRKY45 与大多数 JA-ZIM 结构域家族蛋白 (JAZ) 相互作用，这是 JA 信号传导的关键抑制因子。在被 RKN 南方根结线虫感染后，slwrky45 突变体每克根的瘿数和卵数低于野生型，而 SlWRKY45 的过表达减弱了对南方根结线虫的抗性。在 M. incognita 感染下，SlWRKY45过表达抑制了根中茉莉酸（JA）和JA-异亮氨酸（JA-Ile）的含量。此外，SlWRKY45 结合并抑制 JA 生物合成基因 ALLENE OXIDE CYCLASE (AOC) 的启动子，并抑制其表达。总体而言，我们的研究结果表明，SlJAZ 相互作用蛋白 SlWRKY45 减弱了 RKN 调节的 JA 生物合成并抑制了番茄中对 RKN M. incognita 的防御。