Cloning And Analysis Of Glycosyl Hydrolase Family 7 Genes In The Gut Of Reticulitermes Chinese Snyder

Cellulose is the most abundant biomass on the Earth, and one of the most important industrial material and renewable resources in the nature. Termites can decompose cellulose from the deadwood and defoliation and degrade the soil organic matter. Therefore it can improve soil nutrition and promote the material recycling. Previous studies have shown that termites degrade cellulose with the help of different cellulases. The endogenous cellulases mainly come from intestinal epithelial cells and salivary glands. There are also cellulases originated from termite symbionts. However, so far only a few reports about the diversity of termite cellulases are avaible. The mechanism of cellulose digestion by various termites remains unknown.In this study nine ORFs of cellulase genes from the hindgut fluid of Reticulitermes Chinese Snyder were obtained by RT-PCR and RACE technique. The genes (1353 bp ) encoding 451 amino acid were 98%-99% similar in amino acid sequences with each other. Two genomic cellulase genes with the same length (1353 bp) were obtained by direct amplification from DNA extracted from hindgut fluid, indicating that there are no introns in the studied genomic cellulase gene. Blast search in the GenBank data base showed that the 11 obtained cellulase genes were most closely related to cellulase genes belong to glycosyl hydrolase family 7 detected from symbiotic protists of different wood-feeding termites or cockroaches, indicating the possible protist origin of these genes. The deduced amino acid sequences of the cellulase shared 55%-88% sequence similarity with those of wood-feeding termites or cockroaches. The highest similarity is 88% compared with the GHF7 from Reticulitermes speratus, whereas the lowest similarity is 62% compared with the GHF7 from Mastotermes darwiniensis, indicating the possible co-evolution between cellulases and their termite hosts. Regarding the abundant diversity of termite cellulases, more work should be done in the future to reveal the function and mechanism of various cellulases in the gut of wood-feeding termites like Reticulitermes Chinese.