为了解植物化合防御物质皂苷对专食性天敌莲草直胸跳甲Agasicles hygrophila的防御作用,测定莲草直胸跳甲2龄幼虫取食皂苷后的排泄和肠道变化,利用转录组测序筛选参与皂苷代谢的候选基因,并采用RNA干扰技术鉴定候选基因功能.结果发现,取食皂苷导致莲草直胸跳甲幼虫排泄量增加,肠道畸变,排泄量与取食皂苷浓度正相关.转录组测序发现,与对照相比,取食100 mmol/L皂苷处理的莲草直胸跳甲幼虫肠道有496条差异表达基因,其中261个上调基因和235个下调基因.GO分类和KEGG分类分析发现糖苷水解酶家族1(glycoside hydrolase family 1,GH1)基因集中在碳水化合物水解通路.利用RNA干扰技术鉴定发现,莲草直胸跳甲AghyGH1a基因沉默可导致幼虫取食皂苷后排泄量增加,肠道内容物颜色更暗沉.表明莲草直胸跳甲AghyGH1a参与皂苷代谢.
Abstract
To investigate the defensive role of the chemical defense compound saponin against larvae of the specialized biocontrol natural enemy alligator weed flea beetle Agasicles hygrophila,changes in lar-val excretion and gut were studied following feeding the second-instar larvae with saponin. Transcrip-tomic sequencing was used to analyze candidate genes involved in saponin metabolism,and the func-tions of these genes were identified by using RNA interference (RNAi). Results showed that ingestion of saponin increased larval excretion and caused intestinal distortion compared to the control,with ex-cretion levels positively correlated with saponin concentration. Transcriptome sequencing identified a total of 496 differentially expressed genes in larvae fed with saponin,including 261 up-regulated genes and 235 down-regulated genes. GO classification and KEGG classification analysis revealed enrichment of glycoside hydrolase family 1 (GH1) genes involved in carbohydrate hydrolysis pathways. Using RNAi,silencing of AghyGH1a increased larval excretion and darkened gut contents,indicating its role in saponin metabolism in this beetle.
维普
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