Transcriptomic and proteomic analysis of putative digestive proteases in the salivary gland and gut of Empoasca (Matsumurasca) onukii Matsuda

Abstract

Background: Infestation by tea green leafhoppers, Empoasca (Matsumurasca) onukii , could cause a series of biochemical changes in tea leaves. As a typical cell-rupture feeder, E. onukii secretes proteases while probing with its stylet into the tender shoots of tea plants ( Camellia sinensis ). This study identified and analyzed proteases specifically expressed in the salivary gland (SG) and gut of E. onukii through enzymatic activity assays, complemented with an integrated analysis of transcriptome and proteome data.Results: In total, 129 contigs representing seven types of putative proteases were identified. Transcript abundance of digestive proteases and enzymatic activity assays showed that cathepsin B-like protease, cathepsin L-like protease, and serine proteases (trypsin- and chymotrypsin-like protease) were highly abundant in the gut while moderately abundant in the SG. The abundance pattern of digestive proteases in the SG and gut of E. onukii differed from that of other hemipterans including Nilaparvata lugens , Laodelphax striatellus , Acyrthosiphum pisum , Halyomorpha halys and Nephotettix cincticeps . Phylogenetic analysis showed that aminopeptidase N-like proteins and serine proteases abundant in the SG or gut of hemipterans were distributed to two distinct clusters.Conclusions: Altogether, this study provide insightful information on the digestive system of E. onukii and observed different patterns of proteases abundant in the SG and gut of E. onukii , in comparison with other five hemipteran species. These results will be beneficial in understanding the interaction between tea plants and E. onukii .