大豆bHLH转录因子家族成员的进化及功能分化研究

Evolution and Function Divergence Analysis of the bHLH Transcription Factor Family in Soybean (Glycine max L.)

碱性螺旋-环-螺旋蛋白(basic Helix-Loop-Hleix,bHLH)转录因子家族是动植物中最大的转录因子家族之一,主要由碱性氨基酸区域和螺旋-环-螺旋区域组成,在动植物生长发育和胁迫应答反应中发挥着重要作用.本研究通过对大豆全基因组生物信息学分析和分子生物学研究手段,深入研究了大豆bHLH基因家族的进化机制,同时探讨了该基因家族在大豆中的功能分化.结果表明,大豆中含有340个非冗余的bHLH基因家族成员,通过对这些成员的Pfam蛋白结构域、Motif组成和系统进化关系的分析,将这些成员分为15组共24个亚家族,在大豆20条染色体上呈现不均匀分布.bHLH理化性质差异较大,编码的大豆氨基酸数量为91～815aa,相对分子量为10 273.88～91 300.38,理论等电点为4.56～10.40;碱性氨基酸区含有His5-Glu9-Arg13保守序列,与靶基因结合有关,HLH区含有Arg23和Arg55,与形成二聚体有关,同时含有5种保守元件.多数成员在大豆根以及花发育的5个时期中具有组织表达特异性,不同基因表达量差异较大.

The basic Hclix-Loop-Hlcix (bHLH) gene family,one of the largest plant transcript factor families ,playedan important roleinthegrowthanddevelopment in plantsandanimals.Theevolutionary mecha nism of the soybean bHLH gene family was analyzed) further the function differentiation through bioinformatics and molecular biology methods was discussed. The results showed that the soybean contains 34 0 members of bHLH genes, which can be divided into 24 subgroups through the domain structures, motif compositions and phylogenetic relationships,anddistributedin20chromosomesunevenly.Thechemicalcharacteristic of bHLH geneswere significantly different with the length of amino acidwas 91 ?81 5,the rclativemiolccularwcight was 10 273.88-91 300.38,andthetheoretical equivalencepointvariesfrom4.56to10.40. The alkaline aminoacid region contains the conservative sequence of His5-Glu9-Argl3, which is associated with the target gene. The bHLH region contains Arg23 and Arg55 and contains five conservative elements,which is related to the formation of dimer. Most of the members showed specific tissue expression and different gene expression levels in root and the development of flower in soybean.