小麦TaHKT家族基因的生物信息学分析

Bioinformatic Analysis of the TaHKT Gene Family in Wheat

高亲和性钾离子转运蛋白(high-affinity K+transporter, HKT)是植物体内一种非常重要的离子转运蛋白,具有运输Na+/K+的能力,在植物响应盐胁迫过程中发挥重要作用。为系统了解小麦TaHKT家族基因,挖掘有效的小麦耐盐基因,本研究采用生物信息学的方法,对小麦TaHKT家族基因进行了全基因组分析,鉴定了家族成员,构建了系统进化树,并对其跨膜结构域、染色体定位、基因结构、Motif、上游顺式作用元件、共线性以及表达谱等进行了分析。结果鉴定出23个TaHKT基因,其编码蛋白质长度为443~590 aa,等电点范围8.2~10.4,跨膜结构域为6~8个。23个基因分布于小麦的2、4、6、7号染色体上,根据亲缘关系可将其分为3个亚族,同一亚族的成员具有较为相似的Motif组成和基因结构。23个基因中,发现了4对串联重复基因,10对大片段复制基因,具有良好的共线性。顺式作用元件分析发现,大部分TaHKT成员含有盐胁迫响应元件MYB、G-box、ABRE和DRE。表达谱分析发现,TaHKT基因在小麦的16种组织中均有表达,在根、茎中的表达量较高,其中TraesCS4D02G361300(ID,下同)在根中的表达量最高。在盐胁迫处理后,不同成员对盐胁迫响应程度不同,TraesCS7B02G318400在盐胁迫处理后表达量逐渐降低;TraesCS2B02G451400和TraesCS2D02G428200在盐胁迫处理后的表达量也明显降低;TraesCS2B02G451800在根部几乎不表达,但在受到盐胁迫处理后表达量逐渐提高,推测它们在小麦抵御盐胁迫过程中发挥不同作用。

The high-affinity K+transporter(HKT)is a very important ion transporter protein in plants,with the ability to transport Na+/K+,and plays a crucial role in plant response to salt stress.In order to systematically understand the TaHKT gene family in wheat and explore effective wheat salt tolerance related genes,in this study,we conducted a genome-wide analysis of this gene family,identified the members,constructed a phylogenetic tree,and analyzed their transmembrane structural domains,chromosomal localization,gene structure,motif,upstream cis-acting elements,covariance and expression profiles analysis.As a result,23 TaHKT gene family members have been identified,all of which encoded proteins ranging from 443 to 590 amino acids in length,with 8.2 to 10.4 isoelectric points,and 6 to 8 transmembrane domains.TaHKT genes were distributed on chromosomes 2,4,6 and 7 of wheat and could be divided into three subfamilies according to their genetic phylogeny,and members of the same subfamily had relatively similar motif composition and gene structure.Four pairs of tandem repeat genes and 10 pairs of large fragment duplication genes with good covariance were found among the 23 gene family members.Analysis of cis-acting elements revealed that most gene family members contained salt stress responsive cis-elements:MYB,G-box,ABRE and DRE.Expression profile analysis revealed that TaHKT genes were expressed in all 16 tissues of wheat,especially in roots and stems.TraesCS4D02G361300 showed the highest expression in the root.After salt stress treatment,the expression patterns of different family members differed.The expression of TraesCS7B02G318400 was gradually decreased;TraesCS2B02G451400 and TraesCS2D02G428200 were also significantly decreased;TraesCS2B02G451800 was hardly expressed in roots,but the expression gradually increased,indicating they may play essential roles in wheat tolerance to salt stress.