Main conclusion Linolenic acid produced by the ω-3 fatty acid desaturase MSD3 in sorghum is used for insect-induced jasmonic acid production and is important for resistance against Spodoptera frugiperda . Abstract Jasmonic acid (JA) is a phytohormone that regulates both plant development and stress responses. In sorghum ( Sorghum bicolor ), the ω-3 fatty acid desaturase Multiseeded3 (MSD3) and the 13-lipoxygenase Multiseeded2 (MSD2) are important for producing JA to regulate panicle development and spikelet fertility, but their function in plant defense remains unknown. In this study, we examined whether these genes are important for the production of JA in response to herbivory by the insect pest Spodoptera frugiperda . Compared to wild-type controls, the msd3 mutant accumulated less JA in leaves of both infested and uninfested plants , revealing that MSD3 is involved in stress-induced JA production. In contrast, herbivore-induced JA production in the msd2 mutant was indistinguishable from wild type, indicating that MSD2 does not function in herbivore-induced JA production. An increase of S. frugiperda growth was observed on both the msd3 and msd2 mutants, hinting at roles for both JA and additional oxylipins in sorghum’s defense responses.

中文翻译：

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13-脂氧合酶 MSD2 和 ω-3 脂肪酸去饱和酶 MSD3 影响高粱对草地贪夜蛾的抗性

主要结论 由高粱中的 ω-3 脂肪酸去饱和酶 MSD3 产生的亚麻酸可用于昆虫诱导的茉莉酸生产，并且对抗草地夜蛾具有重要意义。摘要 茉莉酸（JA）是一种调节植物发育和胁迫反应的植物激素。在高粱 ( Sorghum bicolor ) 中，ω-3 脂肪酸去饱和酶 Multiseeded3 (MSD3) 和 13-脂氧合酶 Multiseeded2 (MSD2) 对于产生 JA 以调节穗发育和小穗生育力很重要，但它们在植物防御中的作用仍然未知。在这项研究中，我们检查了这些基因是否对害虫 Spodoptera frugiperda 的草食性反应中 JA 的产生很重要。与野生型对照相比，msd3 突变体在受侵染和未受侵染植物的叶片中积累的 JA 较少，揭示MSD3参与应激诱导的JA产生。相比之下，msd2 突变体中草食动物诱导的 JA 产生与野生型没有区别，表明 MSD2 在草食动物诱导的 JA 产生中不起作用。在 msd3 和 msd2 突变体上都观察到 S. frugiperda 生长的增加，这暗示了 JA 和其他氧化脂在高粱的防御反应中的作用。