Cloning Of CesA Gene Family And Functional Analysis Of CesA3 Gene In Larix Gmelinii

Larix gmelinii is a coniferous tree belonging to Larix of Pinaceae.It is mainly distributed in large and small Xing’an Mountains.It is a tree species for afforestation and forest regeneration in barren mountains.It is widely used as raw materials for housing construction,civil engineering and wood fiber industry.Cellulose is the main component of plant cell wall,which is stored in the primary and secondary walls of plants.Cellulose is mainly synthesized by cellulose synthase(CesA),and the expression abundance of cellulose synthase affects the growth and development of plants.Therefore,it is of great significance to further study the function and expression regulation of cellulose synthase in L.gmelinii to provide effective candidate genes for genetic improvement of wood quality.In this study,firstly,using the transcriptome data of L.gmelinii,the cellulose synthase gene family members of L.gmelinii were cloned and analyzed by bioinformatics.Secondly,based on the above research results,we selected Lg CesA3 gene from the cloned gene family members.On the one hand,we cloned its promoter and analyzed its expression pattern by constructing expression vector and genetic transformation in Arabidopsis;on the other hand,we overexpressed the gene in Arabidopsis through phenotypic analysis,fiber content,hemicellulose,lignin content and so on The function of Lg CesA3 gene was further studied.This work laid a foundation for the research of expression pattern and function analysis of cellulose synthase gene family members.The main results are as follows.1.Based on the transcriptome database of L.gmelinii,six unigenes encoding cellulose synthase were retrieved.The full-length c DNA sequences of these genes were cloned by race and RT-PCR,and named Lg CesA1,Lg CesA3,Lg CesA4,Lg CesA5,Lg CesA6 and Lg CesA8 respectively.Bioinformatics analysis showed that the length of the above six coding sequences were 829-1100aa;the encoded proteins were located on the plasma membrane;they contained conserved functional domains;they belonged to transmembrane proteins;and phylogenetic tree analysis showed that the six coding sequences were divided into two branches.2.Based on the 1623 BP promoter sequence of Larch(L.gmelinii)gene obtained from previous studies,the vector of PORE R1-p Lg CesA3: : GUS was constructed.The gus reporter gene was used to analyze the expression pattern of Lg CesA3.The results showed that the expression of p Lg CesA3 gene was regulated by cis elements such as methyl jasmonate,abscisic acid,auxin and light.3.The function of Lg CesA3 gene was analyzed by screening homozygous lines from T3 generation seeds of transgenic Arabidopsis thaliana.The results showed that the content of cellulose increased and the content of hemicellulose decreased in Lg CesA3 transgenic lines;There was no significant difference in lignin content.