Natural Variations Of E1-E4 Genes In Different Maturity Group Soybeans And Analysis Of The Gene Effects

Soybean is one of the most important crops in the world.The production,quality and maturity traits of soybean are closely related.Soybean varieties have rich genetic diversity in traits of growth.North American Researchers established maturity group system according to the differences of soybean adaption to latitudes,which can distinguish the difference of photoperiod and temperature adaptability of soybean varieties and become an international standard.Traditional genetics study has found a series of gene related to the maturity traits of soybean,which are known as E-series gene.Among them,the effect of E1-E4 genes are the most significant.In this study,126 soybean varieties were selected from the different maturity groups and pot plant in Beijing for investigating of VE,R1,R7 and R8.The genomic DNA was extracted from fresh leaves,and the E1-E4 gene was cloned and sequenced.Sequence polymorphism and haplotype analysis were performed and the phenotypic data were analyzed in order to know the distribution and natural variation of E1-E4 gene in different maturity groups.According to the previous study and if the natural variation change the amino acid sequence,the genotype have been identified in this study as follows:E1:E1?el-as?el-fs?el-nl;E2:E2-in?E2-d1?e2-ns;E3:E3-Ha?E3-Mi?e3-tr?e3-fs?e3-ns;E4:E4?e4-SORE-1?e4-kes?e4-new.e4-new is a novel genotype which have absence gene function by a base deletion in the third exon of the E4 gene.The results of sequencing showed that the E1-E4 genes were conserved and the mutations in the coding region were scarce,suggesting that E1-E4 was subjected to heavy pressure of natural selection.The results showed that the genotypes of E1-E4 gene had obvious distribution boundaries showing a clear pattern of band distribution,and the genotype gradually from the recessive type transits to dominant type with the maturity groups growing.Indicating that the genotype was associated with the maturity groups,and the combinations of genotypes resulted in continuous differences in the maturity groups.Through the clustering analysis of phenotypic data,the whole varieties are divided into three groups,which are:(1)Early maturing varieties which are not sensitive to photoperiod and temperature,and maturity relevant traits are shortened.(2)Varieties which adapt to the photoperiod and temperature of Beijing,and maturity traits are stable.(3)late maturing varieties which are sensitive to photoperiod and temperature,and maturity relevant traits are elongation.Through the analysis of genotype data,the whole varieties are divided into three groups,which are:(1)Most of the E1-E4 gene were recessive genotypes,and the differences in maturity traits were caused by the differences in recessive genotype.(2)The E1-E4 loci showed a mixed state of dominant and recessive genotype,and the difference of maturity traits was caused by different combinations of genotype.(3)E1-E4 gene are dominant genotypes,the differences in maturity traits were caused by other genes.Analysis with maturity groups data we can found that two methods of classification get same result,the varieties could be divided into MG0000-MGO,MGI-MGV,MGVI-MGX 3 group.It is proved that the maturity groups system can distinguish the varieties well.The phenotypic classification results showed that the maturity groups of soybean varieties which can adapt to the photoperiod and temperature of Beijing were MGI-MGV.At the same time,genotyping results divided three groups of soybean varieties with different research focus.Analysis result show that the effect of E1-E4 gene is E1>E2>E3>E4.There was a significant correlation between genotype and maturity traits.The empirical equation was given by linear regressing of genotype and phenotype data.In order to study the effect of the recessive genotype in early maturing soybean varieties,183 varieties were used.The E1-E4 gene identification results and statistic analysis results show that the effect of the e3-tr genotype is between dominant and recessive,have a part of function.el-fs and e3-ns only distributed in early maturing varieties,all of these three genotypes can be used as excellent early-maturing breeding material.