Expression profiles of the trehalose-6-phosphate synthase gene associated with thermal stress in ostrinia furnacalis (Lepidoptera: Crambidae)

Abstract

Trehalose is the major blood sugar in insects. Physiological significance of this compound has been extensively reported. Trehalose-6-phosphate synthase (TPS) is an important enzyme in the trehalose biosynthesis pathway. Full-length cDNAs of TPS (Oftps) and its alternative splicing isoform (Oftps-isoformI) were cloned from the Asian corn borer (ACB), Ostrinia furnacalis (Guenée; Lepidoptera: Crambidae) larvae. The Oftps and Oftps-isoformI transcripts were 2913 and 1689 bp long, contained 2529 and 1293 bp open reading frames encoding proteins of 842 and 430 amino acids with a molecular mass of 94.4 and 48.6 kDa, respectively. Transcriptional profiling and response to thermal stress of Oftps gene were determined by quantitative real-time PCR showing that the Oftps was predominantly expressed in the larval fat body, significantly enhanced during molting and transformation; and thermal stress also induced Oftps expression. Gene structure analysis is indicating that one TPS domain and one trehalose-6-phosphate phosphatase (TPP) domain were located at the N- and C-termini of OfTPS, respectively, while only the TPS domain was detected in OfTPS-isoformI. Three-dimensional modeling and heterologous expression were developed to predict the putative functions of OfTPS and OfTPS-isoformI. We infer that the expression of Oftps gene is thermally induced and might be crucial for larvae survival.