Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China.
Insect Sci. 2013 Jun;20(3):307-17. doi: 10.1111/1744-7917.12002. Epub 2013 Jan 14.
Southwestern corn borer (SWCB, Diatraea grandiosella) and fall armyworm (FAW, Spodoptera frugiperda) are major pests of sorghum in the southern United States. Host plant resistance is a desirable means for reducing plant damage and yield losses from both insects. In this study, we evaluated 12 sorghum lines for whorl-stage resistance to leaf-feeding SWCB and FAW in greenhouse and laboratory bioassays. Differential plant responses were detected against the two insects. Among 12 lines tested, CM1821, Della and PI196583 were resistant to both insects, while BTx2752 was largely susceptible. Line R.09110 was resistant to SWCB, but susceptible to FAW, whereas Redbine-60 was susceptible to SWCB, but not to FAW. In addition, we quantified various chemical components in the plants and determined their association with insect resistance. Tannin and chlorophyll in leaves did not show any significant correlation with resistance to either insects, but contents of soluble protein in general were negatively correlated with resistance to both insects. Endogenous soluble sugar and dhurrin were only positively correlated with resistance to SWCB, but not with FAW resistance. To gain some molecular insight into resistance mechanism of sorghum to SWCB, we performed qPCR reactions for key genes encoding enzymes involved in dhurrin and jasmonic acid (JA) biosynthesis on selected resistant or susceptible lines. Although these genes were rapidly and strongly induced by insect feeding in all lines, the observed resistance is likely explained by higher constitutive dhurrin contents in some resistant lines and higher basal JA biosynthesis in others. Our results suggest that sorghum utilizes multiple strategies to defend itself against SWCB.
南方玉米穗螟（SWCB，Diatraea grandiosella）和秋粘虫（FAW，Spodoptera frugiperda）是美国南部高粱的主要害虫。寄主植物抗性是减少两种昆虫对植物造成损害和产量损失的理想方法。在这项研究中，我们在温室和实验室生物测定中评估了 12 个高粱品系对叶食性 SWCB 和 FAW 的轮生期抗性。检测到针对这两种昆虫的不同植物反应。在测试的 12 个品系中，CM1821、Della 和 PI196583 对两种昆虫均具有抗性，而 BTx2752 则基本易感。品系 R.09110 对 SWCB 具有抗性，但对 FAW 敏感，而 Redbine-60 对 SWCB 敏感，但对 FAW 不敏感。此外，我们量化了植物中的各种化学成分，并确定了它们与昆虫抗性的关联。叶片中的单宁和叶绿素与对两种昆虫的抗性均无显著相关性，但可溶性蛋白质的含量通常与对两种昆虫的抗性呈负相关。内源性可溶性糖和千里光宁仅与对 SWCB 的抗性呈正相关，而与对 FAW 的抗性无关。为了深入了解高粱对 SWCB 抗性的机制，我们对选定的抗性或敏感品系中参与千里光宁和茉莉酸（JA）生物合成的关键基因进行了 qPCR 反应。尽管这些基因在所有品系中都被昆虫取食迅速且强烈地诱导，但观察到的抗性可能是由于一些抗性品系中较高的组成型千里光宁含量和其他品系中较高的基础 JA 生物合成所致。我们的结果表明，高粱利用多种策略来防御 SWCB。
