Reference genes for real-time quantitative reverse transcriptase-PCR In the higher termite Nasutitermes takasagoensis (Isoptera: Termitidae) comparing soldiers with minor workers

In higher termites (family Termitidae), gene expression analysis among the various castes has rarely been carried out, and information about the expression of housekeeping genes is lacking. To evaluate suitable reference genes for use as internal controls in real-time quantitative reverse transcriptase-PCR (qRT-P CR), the partial sequences of four candidate housekeepinggenes (18S ribosomal DNA gene (18S rDNA), beta-actin, elongation factor-1 alpha, and NADH dehydrogenase) were determined in the termitid termite Nasutitermes takasagoensis, whose soldiers perform a highly developed defensive behavior using chemical secretion. The uniform loading of RNA samples of minor worker and soldier heads was conducted, and the equal efficiency of enzyme reactions for each gene was tested. The current analyses suggest that betaactin is the most suitable internal control gene for qRT-PCR studies of gene expression in N. takasagoensis. Studies on soldier-specific gene expression in derived termites are important in order to discuss the evolutional process of termite defensive behavior/weapons, and to determine the mechanism of polyphenism shown in social insects. From this study it was demonstrated that qRT-PCR analysis using beta-actin as a reference gene will be a useful tool for future studies.