Insight into the Functional Diversification of Lipases in the Endoparasitoid Pteromalus puparum (Hymenoptera: Pteromalidae) by Genome-scale Annotation and Expression Analysis.

Jiale Wang,Fang Wang,Hongwei Yao,Gongyin Ye,Qisheng Song,Jiqiang Song,Qi Fang

doi:10.3390/insects11040227

Abstract

Lipases play essential roles in digestion, transport, and processing of dietary lipids in insects. For parasitoid wasps with a unique life cycle, lipase functions could be multitudinous in particular. Pteromalus puparum is a pupal endoparasitoid of butterflies. The female adult deposits eggs into its host, along with multifunctional venom, and the developing larvae consume host as its main nutrition source. Parasitoid lipases are known to participate in the food digestion process, but the mechanism remains unclear. P. puparum genome and transcriptome data were interrogated. Multiple alignments and phylogenetic trees were constructed. We annotated a total of 64 predicted lipase genes belonging to five lipase families and suggested that eight venom and four salivary lipases could determine host nutrition environment post-parasitization. Many putative venom lipases were found with incomplete catalytic triads, relatively long β9 loops, and short lids. Data analysis reveals the loss of catalytic activities and weak triacylglycerol (TAG) hydrolytic activities of lipases in venom. Phylogenetic trees indicate various predicted functions of lipases in P. puparum. Our information enriches the database of parasitoid lipases and the knowledge of their functional diversification, providing novel insight into how parasitoid wasps manipulate host lipid storage by using venom lipases.

Highlights

Lipases (EC 3.1.1.3), defined as triacylglycerol (TAG) acylhydrolases, usually catalyze the hydrolysis of lipids at the lipid–water interface and play a crucial role in controlling lipid uptake, transport, and utilization in insects
Our results showed that three lipase genes were highly expressed in larval salivary glands, screening of venom-specific and salivary-specific in P
It is generally believed that many parasitoid wasps have lost the capability to synthesize lipids themselves and have to obtain lipids from hosts during development

Summary

Introduction

Lipases (EC 3.1.1.3), defined as triacylglycerol (TAG) acylhydrolases, usually catalyze the hydrolysis of lipids at the lipid–water interface and play a crucial role in controlling lipid uptake, transport, and utilization in insects. Most lipases from all organisms can be grouped into six families according to the sequence relationship within the α/β hydrolase fold superfamily of proteins. They are neutral (PF00151), acid (PF04083), lipase (PF01674), lipase (PF01764), GDSL (named after the conserved amino acid motif of Gly, Asp, Ser, and Leu around the active site Ser; PF00657), and hormone-sensitive lipases (PF06350) [1,2]. With a catalytic triad (usually Ser–Asp/Glu–His), which is capable of generating a charge relay system and a highly nucleophilic serine, all lipases from those six families use a two-step reaction mechanism. It contains lots of phospholipases, it is not considered or analyzed in this study

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