Chemistry Research Unit, Center for Medical Agricultural and Veterinary Entomology U.S. Department of Agriculture-Agricultural Research Service, Gainesville, FL, USA.
Plant Stress and Germplasm Development Unit, Cropping Systems Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Lubbock, TX, USA.
Planta. 2020 Sep 23;252(4):62. doi: 10.1007/s00425-020-03475-2.
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. 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.
在高粱中，ω-3 脂肪酸去饱和酶 MSD3 产生的亚油酸被用于诱导茉莉酸的产生，这对于抵抗草地贪夜蛾至关重要。茉莉酸（JA）是一种植物激素，它调节植物的发育和应激反应。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 以调节花序发育和小穗育性非常重要，但它们在植物防御中的功能仍不清楚。在这项研究中，我们研究了这些基因是否在高粱对鳞翅目害虫草地贪夜蛾的取食反应中产生 JA 中发挥重要作用。与野生型对照相比，msd3 突变体在受虫害和未受虫害的植物叶片中积累的 JA 较少，这表明 MSD3 参与了应激诱导的 JA 产生。相比之下，msd2 突变体中诱导的 JA 产生与野生型没有区别，这表明 MSD2 不参与诱导的 JA 产生。观察到 S. frugiperda 在 msd3 和 msd2 突变体上的生长都有所增加，这表明 JA 和其他氧化脂类在高粱的防御反应中都发挥了作用。
