Sambangi Pratyusha, Rani Pathipati Usha
Biology and Biotechnology Division, CSIR-Indian Institute of Chemical Technology, Taranaka, Hyderabad, Andhra Pradesh, India.
Arch Insect Biochem Physiol. 2016 Apr;91(4):230-45. doi: 10.1002/arch.21320. Epub 2016 Feb 18.
Groundnut, Arachis hypogea L., is one of the plant species that synthesizes phenolic compounds, resveratrol and coumaric acid. They are induced as a defense strategy in plant in response to feeding lepidopterans. The present study investigated the role of resveratrol and coumaric acid in producing antiherbivore effects as a direct defense against two major groundnut pests, Spodoptera litura F. and Amsacta albistriga W., and in indirect defense by attracting the egg parasitoid Trichogramma chilonis Ishii under laboratory conditions. The phenolic compounds deterred the feeding of both pests and caused reduction in the larval weights in a dose-dependent manner in leaf disk bioassays. Antioxidant mechanisms of larvae fed with these phenols were measured by estimating the activities of superoxide dismutase (SOD), ascorbate peroxidase (APOX), and catalase (CAT). Enzyme activities increased significantly in experimental larvae, more so in resveratrol-treated than in coumaric acid treated larvae. Feeding larvae with resveratrol and coumaric acid resulted in enhanced activities of detoxifying enzymes, carboxyl esterase (EST), and glutathione-S-transferase (GST) in the midgut tissues of both species, indicating the toxic nature of these compounds. Trichogramma chilonis was more attracted toward coumaric acid treatments in Y-olfactometer tests than to resveratrol. This study contributes to the understanding of the roles of resveratrol and coumaric acid in direct as well as indirect defense, we infer a possible utilization of these compounds in alternate measures of groundnut pest control in future.
花生，即落花生（Arachis hypogea L.），是能够合成酚类化合物、白藜芦醇和香豆酸的植物物种之一。这些化合物作为植物的一种防御策略，在植物受到鳞翅目昆虫取食时被诱导产生。本研究调查了白藜芦醇和香豆酸在产生抗食草动物效应方面的作用，作为对两种主要花生害虫斜纹夜蛾（Spodoptera litura F.）和白纹丽灯蛾（Amsacta albistriga W.）的直接防御，以及在实验室条件下通过吸引卵寄生蜂稻螟赤眼蜂（Trichogramma chilonis Ishii）进行间接防御。在叶盘生物测定中，酚类化合物抑制了两种害虫的取食，并以剂量依赖的方式导致幼虫体重减轻。通过估计超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APOX）和过氧化氢酶（CAT）的活性，测定了取食这些酚类化合物的幼虫的抗氧化机制。实验幼虫的酶活性显著增加，白藜芦醇处理的幼虫比香豆酸处理的幼虫增加得更多。用白藜芦醇和香豆酸喂养幼虫导致两种害虫中肠组织中的解毒酶羧酸酯酶（EST）和谷胱甘肽 - S - 转移酶（GST）的活性增强，表明这些化合物具有毒性。在Y型嗅觉仪测试中，稻螟赤眼蜂对香豆酸处理的吸引力比对白藜芦醇的吸引力更大。本研究有助于理解白藜芦醇和香豆酸在直接和间接防御中的作用，我们推断未来这些化合物可能会被用于花生害虫防治的替代措施中。
