Developmental and tissue-specific expression of CHS1 from Plutella xylostella and its response to chlorfluazuron

The cDNA of chitin synthase-1 gene of Plutella xylostella (PxCHS1) was characterized and expression patterns of the two splice variants PxCHS1A and PxCHS1B were investigated in various developmental stages and in major body tissues by RT-PCR and real-time quantitative PCR (qPCR). The PxCHS1 cDNA was 5461 bp in length with an open reading frame of 4701 bp that encoded a putative protein of 1567 amino acids with predicted molecular mass of 179 kDa. The two splice variants were expressed from the mutually exclusive exons which were same in size (177 bp) but showed only 66% identity at the nucleotide level. Both splice variants were expressed in all developmental stages. The qPCR data suggested an uneven expression of the two variants in the body where expression of PxCHS1A was 3.7-fold higher than that of PxCHS1B. The expression of PxCHS1A was 1.5-fold higher in the head than the body whereas in case of PxCHS1B the difference between head and body was 6.3-fold. Chlorfluazuron did not change the expression of PxCHS1 in larvae.