New Breakthrough in Expansin Gene Research of Tobacco

Recently, the Tobacco functional Genome Innovation team of the Tobacco Research Institute of the Chinese Academy of Agricultural Sciences has made new progress in the research on the cell wall polysaccharide metabolic expansin gene.

Tobacco is an important economic crop in China, and the cell wall material is the main component of tobacco leaf. The structure and composition of cell wall determine the loosening degree of tobacco leaf, which is closely related to the flammability, harmfulness and smoking evaluation of tobacco leaf. How to improve the structure and composition of tobacco cell wall is one of the most basic and core contents in improving tobacco quality and reducing tobacco damage and coke. Expansin is a kind of protein that can cause the relaxation of plant cell wall. It loosens the structure of cell wall by breaking the hydrogen bond between cellulose microfibers or between cellulose and other cell wall polysaccharides.

The tobacco functional genome innovation team systematically analyzed the expansin gene family using the information of the general tobacco genome database, identified more than 50 expansin subfamily genes in tobacco, and analyzed their gene structure, evolutionary relationship, possible cis-acting elements (cis-element) in the gene promoter region and trans-acting factors regulating gene expression. Through expression microarray and real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) analysis, expansin genes such as NtEXPA11, NtEXPB3, NtEX-LA1 and NtEXLB2 were found to be specifically and highly expressed in tobacco leaves or senescent leaves.