大豆脱落酸受体基因家族鉴定、系统发育进化及表达模式分析

Identification,phylogenetic evolution and expression analysis of abscisic acid receptors gene family in Glycine max L.Merr

【目的】鉴定大豆脱落酸受体基因(GmPYLs)家族成员,并进行系统发育进化及表达模式分析,为深入研究该基因家族在大豆生长发育和非生物胁迫中的作用机制提供理论依据。【方法】以拟南芥PYLs基因(AtPYLs)家族成员序列为参考,从JGI和NCBI数据库鉴定出GmPYLs基因家族成员;利用生物信息学方法对该基因家族的组成、基因结构、保守性、系统进化、启动子区顺式作用元件及其编码蛋白理化性质和结构域等进行全面分析,并基于转录组测序数据,对GmPYLs基因家族成员的表达模式进行分析。【结果】从大豆全基因组序列中鉴定出21个GmPYLs基因,长度为500~4000 bp,分布在15条染色体上,编码蛋白的氨基酸数量为178~267个,分子量为19457.11~29105.43 Da,理论等电点(pI)为4.82~7.23,均为亲水蛋白,但稳定性存在明显差异,主要定位于细胞质中。GmPYLs蛋白的二级结构以α-螺旋和无规则卷曲为主。GmPYLs基因家族成员可分为四大组,同一组成员基因结构及其编码蛋白的氨基酸序列、三级结构、结构域和保守基序(motif)均相似。大豆、拟南芥、苜蓿和水稻的PYLs基因被分为五大类群(Ⅰ~Ⅴ),大豆、拟南芥、水稻和苜蓿的大多数PYLs基因归于Ⅰ、Ⅱ和Ⅲ类群;Ⅳ类群含少量的拟南芥和大豆PYLs基因,而Ⅴ类群仅含少部分苜蓿PYLs基因。拟南芥与大豆直系同源基因对数量多于拟南芥与苜蓿直系同源基因对数量。21个GmPYLs基因的启动子序列主要包含响应逆境胁迫、调节生长发育及响应植物激素的顺式作用元件,且所有GmPYLs基因的启动子区至少含有1个植物激素响应元件,其中,以含ABA响应元件的GmPYLs基因数量最多。GmPYLs基因具有组织表达特异性,且品种间的表达模式也存在差异。【结论】GmPYLs基因家族成员在系统发育进化上较保守,其基因组复制事件可能发生在豆科植物分化以后,且大部分GmPYLs基因被保留,在响应非生物胁迫中存在广泛的潜在机制,尤其与激素响应密切相关。

【Objective】The abscisic acid receptor gene family in Glycine max L. Merr GmPYLs was identified by bioinformatics,and analyzed its evolution model and expression pattern. The purpose of this study was to provide a theoretical basis for in-depth study of the role of PYL gene in soybean development and abiotic stress.【Method】The reported members of PYLs gene family in Arabidopsis thaliana(AtPYLs)were used as a reference,and the members of GmPYLs gene family were identified by JGI and NCBI databases. The gene family composition,gene structure,conservatism,evolutionary relationship,cis-acting element of promoter region,and its coding protein physicochemical properties and domain were analyzed by bioinformatics method. Based on high throughput transcriptome sequencing data,the expression patterns of GmPYLs gene family members were analyzed.【Result】In this study,21 GmPYLs genes were identified from soybean whole genome sequence,which were distributed on 15 chromosomes with a sequence length of 500-4000 bp.The protein encoded was 19457.11-29105.43 Da in molecular weight,amino acids number was 178 to 267,theoretical isoelectric point(PI)was 4.82-7.23,which was hydrophilic protein mainly distributed in the cytoplasm. But the stability was different. The secondary structure of the protein was mainly α-helix and random coil. The GmPYLs gene family could be divided into four groups. In the same group,the gene structure,amino acid sequence of conded protein,protein tertiary structure,functional domain and conserved motif were very similar. The PYLs genes of G. max,Arabidopsis thaliana,Oryza sativa and Medicago truncatula were divided into five groups(Ⅰ-Ⅴ). Most of the PYLs genes in G. max,Arabidopsis thaliana,Oryza sativa and Medicago truncatula were classified into groups Ⅰ,Ⅱ and Ⅲ. Group IV contained a small amount of AtPYLs and GmPYLs genes,while group Ⅴ contained only a small part of MtrPYLs genes. The promoter sequences of 21 GmPYLs genes mainly contained cis-acting elements that responded to stress,regulate growth and respond to plant hormones. The promoter regions of all GmPYLs genes contained at least one hormone response element,of which the largest number of GmPYLs genes containing ABA response elements. The results of transcriptome sequencing analysis showed that GmPYLs gene had tissue-specific expression|,and there were differences in the expression patterns between different varieties.【Conclusion】Members of the GmPYLs gene family are conservative in phylogenetic evolution,and their genome replication events may occur after legume differentiation,and most of the GmPYLs genes are retained. There are a wide range of potential mechanisms in response to abiotic stress,closely related to hormone response.