An Insect Counteradaptation against Host Plant Defenses Evolved through Concerted Neofunctionalization
An Insect Counteradaptation against Host Plant Defenses Evolved through Concerted Neofunctionalization
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DOI：
10.1093/molbev/msz019
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发表时间：
2019-05-01
影响因子：
10.7
通讯作者：
Kroymann, Juergen
中科院分区：
文献类型：
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作者：
Heidel-Fischer, Hanna M.;Kirsch, Roy;Kroymann, Juergen
植食性昆虫与其寄主植物之间的拮抗性化学相互作用通常被认为是逐步共同进化的过程，其中一方的进化创新被另一方的相应进步所抵消。硫代葡萄糖苷硫酸酯酶（GSS）的活性是小菜蛾，小菜蛾，克服一个高度多样化的次生代谢物为基础的宿主防御系统中的小菜蛾。GSS基因位于一个古老的arylsulfataselike基因簇中，但基因拷贝的确切作用及其进化轨迹尚不清楚。在这里，我们结合联合收割机的功能调查重复的昆虫芳基硫酸酯酶与相关的核苷酸取代模式的分析。我们发现，小菜蛾基因组编码三个GSS不同的底物光谱和不同的表达模式，以响应芥子油苷。与我们的预期相反，基因拷贝的早期功能多样化并不表明宿主和草食动物之间存在共同进化的军备竞赛。相反，重复芳基硫酸酯酶基因的两个拷贝在昆虫宿主转移的背景下协同进化，以在正选择下获得新的解毒功能，我们称之为“协同新功能化”的重复基因保留模式。"
Antagonistic chemical interactions between herbivorous insects and their host plants are often thought to coevolve in a stepwise process, with an evolutionary innovation on one side being countered by a corresponding advance on the other. Glucosinolate sulfatase (GSS) enzyme activity is essential for the Diamondback moth, Plutella xylostella, to overcome a highly diversified secondary metabolite-based host defense system in the Brassicales. GSS genes are located in an ancient cluster of arylsulfataselike genes, but the exact roles of gene copies and their evolutionary trajectories are unknown. Here, we combine a functional investigation of duplicated insect arylsulfatases with an analysis of associated nucleotide substitution patterns. We show that the Diamondback moth genome encodes three GSSs with distinct substrate spectra and distinct expression patterns in response to glucosinolates. Contrary to our expectations, early functional diversification of gene copies was not indicative of a coevolutionary arms race between host and herbivore. Instead, both copies of a duplicated arylsulfatase gene evolved concertedly in the context of an insect host shift to acquire novel detoxifying functions under positive selection, a pattern of duplicate gene retention that we call "concerted neofunctionalization."