Teng Dong, Jing Weixia, Lv Beibei, Huang Xinzheng, Zhao Danyang, Kou Junfeng, Liu Xiaohe, Dhiloo Khalid Hussain, Zhang Yongjun
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
Front Plant Sci. 2023 Sep 5;14:1249226. doi: 10.3389/fpls.2023.1249226. eCollection 2023.
Jasmonic acid (JA) and methyl jasmonate (MeJA), the crucial plant hormones, can induce the emission of plant volatiles and regulate the behavioral responses of insect pests or their natural enemies. In this study, two jasmonic acid carboxyl methyltransferases (JMTs), GhJMT1 and GhJMT2, involved in MeJA biosynthesis in were identified and further functionally confirmed. , recombinant GhJMT1 and GhJMT2 were both responsible for the conversion of JA to MeJA. Quantitative real-time PCR (qPCR) measurement indicated that and were obviously up-regulated in leaves and stems of after being treated with MeJA. In gas chromatography-mass spectrometry (GC-MS) analysis, MeJA treatment significantly induced plant volatiles emission such as ()-β-ocimene, ()-3-hexenyl acetate, linalool and (3)-4,8-dimethyl-1,3,7-nonatriene (DMNT), which play vital roles in direct and indirect plant defenses. Moreover, antennae of parasitoid wasps showed electrophysiological responses to MeJA, β-ocimene, -3-hexenyl acetate and linalool at a dose dependent manner, while our previous research revealed that DMNT excites electrophysiological responses and behavioral tendencies. These findings provide a better understanding of MeJA biosynthesis and defense regulation in upland cotton, which lay a foundation to JA and MeJA employment in agricultural pest control.
茉莉酸（JA）和茉莉酸甲酯（MeJA）是关键的植物激素，可诱导植物挥发物的释放，并调节害虫或其天敌的行为反应。在本研究中，鉴定了两个参与陆地棉中MeJA生物合成的茉莉酸羧基甲基转移酶（JMTs），即GhJMT1和GhJMT2，并进一步进行了功能验证。重组GhJMT1和GhJMT2均负责将JA转化为MeJA。定量实时PCR（qPCR）检测表明，用MeJA处理后，陆地棉叶片和茎中的GhJMT1和GhJMT2明显上调。在气相色谱 - 质谱（GC-MS）分析中，MeJA处理显著诱导了植物挥发物的释放，如（）-β-罗勒烯、（）-3-己烯基乙酸酯、芳樟醇和（3）-4,8-二甲基-1,3,7-壬三烯（DMNT），它们在植物直接和间接防御中起重要作用。此外，寄生蜂的触角对MeJA、β-罗勒烯、-3-己烯基乙酸酯和芳樟醇呈现剂量依赖性的电生理反应，而我们之前的研究表明DMNT能激发电生理反应和行为倾向。这些发现有助于更好地理解陆地棉中MeJA的生物合成和防御调节，为JA和MeJA在农业害虫防治中的应用奠定了基础。
