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

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.

Genome-Wide Identification and Analysis of Lipases in Fig Wasps (Chalcidoidea, Hymenoptera)

“…In this study, we identified a total of 481 lipase genes in 12 fig wasp species belonging to neutral, acid, lipase3, GDSL and HSL lipase gene families. Lipase2 was not found in fig wasps, which was consistent with the lack of lipase2 in other insects [ 14 ]. This is the first investigation of the lipase gene family in fig wasps.…”

“…Compared with two phylogenetic related N. vitripennis and A. mellifera , we can see the number of lipases in N. vitripennis (62) was close to that of P. tridentata . However, the A. mellifera (26) had the least number of lipases in the reported insects [ 14 ]. The expansion and contraction analysis also revealed that A. mellifera as well as all the PFWs had a significant contraction.…”

“…Horne, et al [ 13 ] investigated the lipase of five insect species and found that the total number of the lipases varied two-fold. Five lipase gene families were identified in insects, among which the neutral and acid lipases were the two most abundant families, occupying from 69.23% ( Apis mellifera ) to 92.86% ( Drosophila melanogaster ) of the total number of lipases [ 13 , 14 ]. Neutral lipase family genes in Drosophila underwent multiple tandem duplication events leading to the expansion of gene family size [ 15 ].…”

“…Neutral lipase family genes in Drosophila underwent multiple tandem duplication events leading to the expansion of gene family size [ 15 ]. However, most of the insect lipases lack TAG hydrolysis activity, even though the acid lipases had intact cap domains required for TAG hydrolysis [ 14 ]. Wang, et al [ 14 ] also found the loss of catalytic activities and weak TAG hydrolytic activities of lipases in the venom of the parasitoid wasp Pteromalus puparum .…”

“…However, most of the insect lipases lack TAG hydrolysis activity, even though the acid lipases had intact cap domains required for TAG hydrolysis [ 14 ]. Wang, et al [ 14 ] also found the loss of catalytic activities and weak TAG hydrolytic activities of lipases in the venom of the parasitoid wasp Pteromalus puparum . Thus, the biological significance of lipase diversity remains unclear.…”