商陆PaHAK1与拟南芥HAK/KUP/KT家族基因的比较分析

Comparative analysis of HAK/KUP/KT gene family in Arabidopsis thaliana and PaHAK1 in Phytolacca acinosa

为探明商陆高亲和性K+转运体基因(Pa HAK1)的结构、功能及商陆耐低钾的原因,分析比较了商陆Pa HAK1和拟南芥HAK/KUP/KT家族基因中15个基因编码的高亲和性钾离子转运体氨基酸序列、蛋白质结构及其理化性质。结果表明:HAK基因家族编码蛋白均定位于细胞膜上,含有多个跨膜结构且跨膜结构域是蛋白质的保守结构域;Pa HAK1与At KUP3的跨膜结构十分相似,低钾胁迫下Pa HAK1和At KUP3的高表达与其高亲和钾转运吸收功能密切相关。系统进化树分析结果表明,Pa HAK1与拟南芥HAK基因家族中At KUP8亲缘关系最近,其氨基酸序列相似度为76.98%,推测Pa HAK1还可能通过维持细胞内高水平钾量在水分胁迫下发挥重要的调节作用。

In order to explore the structure and function of the high affinity potassium transporter gene of Phytolacca acinosa Roxb（Pa HAK1） and analyze the reasons of tolerance to low potassium in Phytolacca acinosa Roxb, the amino acid sequences and protein structures and physicochemical properties of 15 high affinity potassium ion transporters in HAK/KUP/KT gene family of Arabidopsis thaliana and Pa HAK1 of Phytolacca acinosa Roxb were compared. The results showed that all coding proteins were orientated on cell membrane, and they contained multiple transmembrane domain with conserve amino acid sequences. The transmembrane structure of Pa HAK1 was very similar to that of At KUP3, and the high expression of Pa HAK1 and At KUP3 under low potassium stress was closely related to the high affinity potassium transport and absorption function. Phylogenetic analysis showed that Pa HAK1 had the closest evolutionary relationship with At KUP8 in Arabidopsis thaliana HAK gene families. Their amino acid sequences similarity was 76.98%. It is suggested that Pa HAK1 also plays an important regulatory role under water stress by maintaining a high level of intracellular potassium.