Identification And Characteristic Analysis Of SBP Gene Family In Foxtail Millet

SBP(SQUAMOSA PROMOTER BINDING PROTEIN)protein is a transcription factor and specific to plants,which plays an important role in the process of growth,development and environmental response.Foxtail millet is a grass C4 plant with a smaller genome(~510 Mb).Although many transcription factor gene families have been identified in foxtail millet,there is little information concerning SBP genes function in foxtail millet.In this study,`Yugu-1` was used to identify SBP gene family in foxtail millet,and analyze the physicochemical characteristics and phylogeny of SBP proteins.The expression of Si SBP gene family under PEG and ABA stress is analyzed by RT-q PCR.This study provides theoretical basis for the gene function research of the Si SBP gene family in growth and stress response,and also lays the foundation for the mining and utilization of millet functional genes.The main results of the study are as follows:1.There are 19 Si SBPs genes in the foxtail millet's genome,and the 19 Si SBPs genes are distributed on 9 chromosomes of foxtail millet.Each staining contains 1 to 4 members of the Si SBP gene family.The amino acid sequence of Si SBPs protein is 199 ~ 1118 aa.The conserved domain of Si SBP proteins in foxtail millet consists of 74 to 76 amino acid residues,all of them have a zinc-binding DNA binding domain.Si SBP proteins are divided into seven subgroups.They have 2 to 11 exons,and all of them are hydrophilic proteins.Si SBP proteins have signals in the nucleus except for Si SBP7.The Si SBP proteins are closer to the SBP proteins in sorghum and rice.2.The cis-acting elements in the promoter region of Si SBP gene family in foxtail millet mainly are response elements of plant hormone,drought,light and pathogenic bacteria,and wounds.RT-q PCR analysis under the stress of PEG and ABA shows that the expression of Si SBP2,Si SBP3,Si SBP8,Si SBP9,Si SBP11,Si SBP12 and Si SBP13 are up-regulated in leaves and stems,and the increased expression in leaves is higher than in stems.Comparedwith exogenous ABA stress,Si SBPs gene expression are appreciably increased after PEG stress treatment.3.The number of amino acids in Si SBP15 protein is 1118 aa.The Si SBP15 gene is mainly expressed in the tassel.Analysis of the promoter indicates that the main function of the Si SBP15 gene is to participate in seed development.Si SBP15 can participate the millet's response to abiotic stress and exogenous hormone induction.4.The number of amino acids in Si SBP19 protein is 968 aa.The expression of Si SBP19 gene is high in leaves and stems.Gene interactions indicate that Si SBP19 gene is involved in the metabolic pathway of plant carbohydrates,protein biosynthesis and degradation.Si SBP19 can also participate in foxtail millet's response to abiotic stress and exogenous hormone induction.