Localization of cellulolytic system and de novo transcriptome analysis of whole larval gut of Zophobas morio (Coleoptera: Tenebrionidae) disclosed the existence of glycosyl hydrolase family-9

Abstract

The present study was aimed at localizing the cellulolytic system in the larval gut of Zophobas morio. Quantitative analysis revealed maximum cellulolytic activity in the midgut followed by foregut and hindgut. Additionally, examination of physicochemical characterization showed the highest endogenous cellulase activity of 2250.32 U/mg at 40°C and the enzyme was stable between pH 5 and 6. Distinct patterns of influence of divalent cations were also found. De novo transcriptome analysis of whole gut envisaged the prevalence of the endogenously transcribed cellulase gene. The assembled transcriptome identified the existence of an isoform of endoglucanase with significant resemblance to glycosyl hydrolase family-9 (GH9). Twenty-seven other members of GH family were also revealed in the study. Consequently, the existence of independent cellulolytic system with the larvae possessing its own cellulolytic gene belonging to the GH9 as revealed by the transcriptome makes them an optimum resource for bioenergy research.