Sahu Smaranika, Dutta Abinash, Ray Dinesh Kumar, Pradhan Jyotsnarani, Dandapat Jagneshwar
Department of Biotechnology, Utkal University, Bhubaneswar, Odisha, India.
Ion Beam Laboratory, Institute of Physics, Bhubaneswar, Odisha, India.
Comp Biochem Physiol B Biochem Mol Biol. 2018 Sep;223:39-49. doi: 10.1016/j.cbpb.2018.06.004. Epub 2018 Jun 30.
Tasar silkworm, Antheraea mylitta is a polyphagous insect that primarily feeds on Terminalia arjuna, Terminalia tomentosa and Shorea robusta. However, larval rearing on S. robusta results in poor performance for the reasons unexplored. Oxidative burden imposed by host plants is presumed to be a determining factor for larval fitness. With this hypothesis we have analyzed the foliar constituents of the respective host plants, the levels of oxidative stress and antioxidant protection in the larval tissues in response to their altered feeding on different host plants for different durations (2 and 10 days). Results indicate that S. robusta leaves contain the highest amount of tannin and redox active metals compared to those of other host plants. Consequently, hemolymph and midgut tissues of the larvae shifted to S. robusta exhibited oxidative predominance. Increased activities of superoxide dismutase, catalase and glutathione S-transferase in the larval tissues indicated an adaptive response to host plant driven oxidative assault. Our in vitro study also strongly supplements the in vivo findings indicating S. robusta foliages as a strong inducer of lipid peroxidation (LPx). Copper and Iron were found to be more potent in inducing LPx in the midgut tissues of the larvae compared to Zinc and Manganese. This study for the first time demonstrates the combined implications of host plant derived allelochemicals and elements on oxidative stress and antioxidant plasticity in this insect. The overall findings also brace up the newly emerging concept on joint effects hypothesis (organic and elemental defence) for enhanced plant defence.
柞蚕，即印度柞蚕，是一种多食性昆虫，主要以印度乌檀、毛叶印度乌檀和娑罗双为食。然而，以娑罗双饲养幼虫时，其生长性能不佳，原因尚未明确。宿主植物施加的氧化负担被认为是幼虫健康状况的决定因素。基于这一假设，我们分析了相应宿主植物的叶片成分，以及幼虫组织在不同时长（2天和10天）以不同宿主植物为食后，其氧化应激水平和抗氧化保护情况。结果表明，与其他宿主植物相比，娑罗双叶片中的单宁和氧化还原活性金属含量最高。因此，转食娑罗双的幼虫血淋巴和中肠组织呈现氧化优势。幼虫组织中超氧化物歧化酶、过氧化氢酶和谷胱甘肽S -转移酶活性增加，表明对宿主植物引发的氧化攻击有适应性反应。我们的体外研究也有力地补充了体内研究结果，表明娑罗双叶片是脂质过氧化（LPx）的强诱导剂。与锌和锰相比，铜和铁在诱导幼虫中肠组织脂质过氧化方面更具效力。本研究首次证明了宿主植物衍生的化感物质和元素对该昆虫氧化应激和抗氧化可塑性的综合影响。总体研究结果也支持了关于增强植物防御的联合效应假说（有机和元素防御）这一新兴概念。
