Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
Instituto de Biotecnología, Universidad Nacional Autónoma de México, 61500, Cuernavaca, Morelos, Mexico.
Cell Mol Life Sci. 2018 Sep;75(17):3215-3229. doi: 10.1007/s00018-018-2768-1. Epub 2018 Feb 9.
True Bugs (Insecta: Heteroptera) produce venom or saliva with diverse bioactivities depending on their feeding strategies. However, little is known about the molecular evolution of the venom toxins underlying these biological activities. We examined venom of the giant fish-killing water bug Lethocerus distinctifemur (Insecta: Belostomatidae) using infrared spectroscopy, transcriptomics, and proteomics. We report 132 venom proteins including putative enzymes, cytolytic toxins, and antimicrobial peptides. Over 73% (96 proteins) showed homology to venom proteins from assassin bugs (Reduviidae), including 21% (28 proteins from seven families) not known from other sources. These data suggest that numerous protein families were recruited into venom and diversified rapidly following the switch from phytophagy to predation by ancestral heteropterans, and then were retained over > 200 my of evolution. In contrast, trophic switches to blood-feeding (e.g. in Triatominae and Cimicidae) or reversions to plant-feeding (e.g., in Pentatomomorpha) were accompanied by rapid changes in the composition of venom/saliva, including the loss of many protein families.
真昆虫（昆虫纲：半翅目）根据其取食策略产生具有多种生物活性的毒液或唾液。然而，对于这些生物活性所依赖的毒液毒素的分子进化知之甚少。我们使用红外光谱、转录组学和蛋白质组学研究了巨型食鱼水黾（Lethocerus distinctifemur）（昆虫纲：田鳖科）的毒液。我们报告了 132 种毒液蛋白，包括推测的酶、细胞毒素和抗菌肽。超过 73%（96 种蛋白）与猎蝽（Reduviidae）的毒液蛋白具有同源性，包括 21%（来自七个家族的 28 种蛋白）来自其他来源。这些数据表明，大量蛋白家族被招募到毒液中，并在祖先半翅目动物从植食性转变为捕食性后迅速多样化，然后在 >2 亿年的进化过程中被保留下来。相比之下，向吸血（例如在三锥虫科和锥蝽科）或返回到植物食性（例如在半翅目）的营养转变伴随着毒液/唾液组成的快速变化，包括许多蛋白家族的丧失。
