Differential expression patterns of two delta-9-acyl-CoA desaturases in (Lepidoptera: Hepialidae) during different seasons and cold exposure.

larvae have a limited distribution in the Tibetan Plateau and are the host of a parasitic fungus, . Low temperature is a main environmental stress. However, understanding of cold adaptation mechanisms is insufficient. Delta-9-acyl-CoA desaturase (D9D) is closely correlated with cold adaptation for many organisms. To further understand the cold adaptation processes in larvae, two s, and were sequenced, and expression patterns were investigated during different seasons and cold exposure (under 0°C) in the laboratory. The full lengths of two cDNAs are 1,290 bp and 1,603 bp, and the ORFs encode a polypeptide of 348 and 359 amino acids, respectively. Four transmembrane domains, three conserved histidine residues and five hydrophobic regions exist in these two sequences. The expression level of is up-regulated in the long-term cold exposure and negatively correlated with temperature in seasonal patterns. responds to cold temperature in short-term cold exposure and positively corresponds temporarily in seasonal expression. Two s may have different substrate specificities, tends to use C16:0 and C18:0 as substrate while prefers C18:0. In conclusion, may play a very important role in cold tolerance and regulates function in short-term cold exposure and content change of fatty acids in the body.