不同水稻种质中渗透胁迫抗性基因DREB2A的遗传多样性分析

本研究旨在分析转录因子DREB2A基因在不同水稻种质中的遗传多样性,以期为水稻耐渗透胁迫遗传改良提供分子工具。利用单倍型分析、系统进化树、遗传距离和密码子偏好性分析,对85份不同类型水稻种质中DREB2A基因的功能性核苷酸序列变异及遗传多样性进行了研究。共鉴定出55个核苷酸变异位点,其中12个位于编码区,43个位于非编码区;鉴定出12个DREB2A等位基因型,其中来自非洲栽培稻(Oryza glaberrima)的3个等位基因型表现大片段变异;根据DREB2A基因的序列变异鉴定出39个单倍型,其中33个为新单倍型;将所有单倍型分为三组（Group I、II和III）,其中非洲栽培稻(Oryza glaberrima)中的10个单倍型单独分为一组(Group III);系统进化树、遗传距离和密码子偏好性分析均表明Group III与其他两组具有较大差异。对85份不同类型水稻种质中DREB2A基因的序列分析表明,非洲栽培稻(Oryza glaberrima)中的DREB2A等位基因在序列变异、系统进化关系和密码子偏好性方面均明显不同于其他种质材料中的等位基因。

DREB2A Gene Resistant to Osmotic Stress in Rice Germplasms: Genetic Diversity Analysis

The purpose is to analyze the genetic diversity of DREB2A gene in different rice germplasms and to provide molecular tools for genetic improvement of osmotic stress-resistance in rice. Haplotype analysis, phylogenetic tree, genetic distance and codon preference analysis were used to study the functional nucleotide sequence variation and genetic diversity of DREB2A gene in 85 rice germplasms of different types. A total of 55 nucleotide mutation sites were identified, 12 of which were located in the coding region and 43 were located in the non-coding region. Twelve DREB2A alleles were identified, including 3 alleles of African cultivated rice (Oryza glaberrima) with large block variation; and 39 haplotypes were identified according to sequence variations of the DREB2A, of which 33 were new haplotypes; all haplotypes were divided into three groups (Group I, II and III), and Group III was made of 10 haplotypes from African rice; Group III showed greater differences with other two groups according to phylogenetic tree, genetic distance and codon usage preference analysis. Sequence analysis of DREB2A genes in 85 rice germplasms of different types showed that DREB2A alleles in African rice were apparently different to the alleles from other types of germplasms in sequence variation, phylogenetic relationship and codon preference.