Genome-wide Identification And Expression Analysis Of WOX And LBD Family Gene During Adventitious Root Development In Tea Plant

Adventitious root formation is a key link in asexual propagation of tea trees.In this study,‘Shan C ha No.1’ was used as the material and treated with exogenous hormones under hydroponic condition.The whole genome was used to identify WUSCHEL-related homeobox(WOX)and Lateral organ boundaries domain(LBD)family members and analyze their expression characteristics during adventitious root formation.Tobacco transformation analysis was carried out on candidate key family members to analyze the function of genes in regulating adventitious root formation,providing theoretical basis for the study of physiological and molecular mechanisms of adventitious root formation,and providing certain technical guidance for production practice and theoretical guiding significance for fine variety breeding of tea trees.The main results are as follows:1.A total of 19 WOX genes and 56 LBD genes were identified.The open reading frame of WOX gene is 519bp-2121 bp,the amino acid length of WOX protein is 172 aa-706 aa,the molecular weight of WOX is 19 461.41 da-81150.51 da,and the isoelectric point of WOX protein is 5.09-9.3.The open reading frame length of LBD gene is 372 bp to 1206 bp,the amino acid length of LBD protein is 123 aa to 401 aa,the molecular weight of LBD is13608.71 Da to 45071.59 Da,and the isoelectric point of LBD protein is 4.59 to 9.37.WOX is divided into three groups,of which WUS branch contains 11 tea tree WOX proteins,middle branch contains 3 tea tree WOX proteins,and ancient branch contains 5tea tree WOX proteins.LBD can be divided into two categories.C lass I protein contains 46 tea tree LBD proteins and C lass II protein contains 10 tea tree LBD proteins.WOX has 2-9conservative motifs and LBD has 3-6 conservative motifs.Four possible genes related to adventitious root development were screened out.Four possible genes related to adventitious root development were screened out,include Cs LBD17,Cs LBD18,Cs LBD47 and Cs LBD48.2.It was proved that exogenous application of 1×10-6 mol/L melatonin and 1×10-6mol/L salicylic acid could significantly promote adventitious root formation in tea plants.Gene expression analysis of adventitious root generation process shows that the four tea tree LBD genes of Cs LBD17,Cs LBD18,Cs LBD47 and Cs LBD48 can regulate the occurrence of adventitious root.It is preliminarily shown that the four genes,namely,Cs LBD17,Cs LBD18,Cs LBD17,and Cs LBD18,can regulate adventitious root formation in tea plants.C loning and obtaining Cs LBD17,Cs LBD18,Cs LBD47,Cs LBD48 gene sequences,the open reading frame length of Cs LBD17 gene is 699 bp,the amino acid length of the protein is 232 aa,the molecular weight is 25879.95,and the isoelectric point is5.61;The open reading frame length of the Cs LBD18 gene is 609 bp,the amino acid length of the protein is 202 aa,the molecular weight is 21992.25,and the isoelectric point is 8.39.The open reading frame length of the Cs LBD47 gene is 576 bp,the amino acid length of the protein is 191 aa,the molecular weight is 21046.17,and the isoelectric point is 6.88.The open reading frame length of Cs LBD48 gene is 696 bp,the amino acid length of the protein is 231 aa,the molecular weight is 25364.23,and the isoelectric point is 5.76.The overexpression vectors of these four genes were constructed,and the Cs LBD18 gene was transformed into tobacco,and 9 positive overexpressed plants were obtained.the Phenotype showed that the number and length of adventitious roots were better than those of wild type.But the gene function needs further verification.