Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-Agriculture, Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, School of Wetland, Yancheng Teachers University, Yancheng, 224001, Jiangsu, China.
Genetica. 2020 Apr;148(2):87-99. doi: 10.1007/s10709-020-00090-7. Epub 2020 Feb 24.
Crabs feed on a wide range of items and display diverse feeding strategies. The primary objective of this study was to investigate 10 digestive enzyme genes in representative crabs to provide insights into the genetic basis of feeding habits among crab functional groups. Crabs were classified into three groups based on their feeding habits: herbivores (HV), omnivores (OV), and carnivores (CV). To test whether crabs' feeding adaptations matched adaptive evolution of digestive enzyme genes, we examined the 10 digestive enzyme genes of 12 crab species based on hepatopancreas transcriptome data. Each of the digestive enzyme genes was compared to orthologous sequences using both nucleotide- (i.e., PAML and Datamonkey) and protein-level (i.e., TreeSAAP) approaches. Positive selection genes were detected in HV crabs (AMYA, APN, and MGAM) and CV crabs (APN, CPB, PNLIP, RISC, TRY, and XPD). Additionally, a series of positive selection sites were localized in important functional regions of these digestive enzyme genes. This is the first study to characterize the molecular basis of crabs' digestive enzyme genes based on functional feeding group. Our data suggest that HV crabs have evolved an enhanced digestion capacity for carbohydrates, and CV crabs have acquired digestion capacity for proteins and lipids.
螃蟹以广泛的食物为食，并表现出多样化的摄食策略。本研究的主要目的是研究代表螃蟹中的 10 种消化酶基因，以了解螃蟹功能群摄食习性的遗传基础。根据摄食习性，螃蟹分为三类：草食性（HV）、杂食性（OV）和肉食性（CV）。为了测试螃蟹的摄食适应性是否与消化酶基因的适应性进化相匹配，我们根据肝胰腺转录组数据，对 12 种螃蟹物种的 10 种消化酶基因进行了研究。使用核苷酸（即 PAML 和 Datamonkey）和蛋白质水平（即 TreeSAAP）方法，将每个消化酶基因与同源序列进行比较。在 HV 螃蟹（AMYA、APN 和 MGAM）和 CV 螃蟹（APN、CPB、PNLIP、RISC、TRY 和 XPD）中检测到正选择基因。此外，在这些消化酶基因的重要功能区域中还定位了一系列正选择位点。这是首次基于功能摄食群对螃蟹消化酶基因的分子基础进行描述的研究。我们的数据表明，HV 螃蟹进化出了对碳水化合物更强的消化能力，而 CV 螃蟹则获得了对蛋白质和脂肪的消化能力。
