陆地棉钾吸收相关基因GhHAK1的克隆与功能分析

棉花是一种典型的喜钾经济作物,其产量和品质形成与钾含量密切相关。克隆获得棉花高亲和性钾转运体基因GhHAK1框,系统进化树表明该GhHAK1基因属于第Ⅰ亚族,此分支被认为介导高亲和性K+。膜结构预测显示该基因编码的蛋白跨膜螺旋区域(TMS)有12个,且在第2和第3 TMS之间有一个较长的胞质质环。洋葱表皮亚细胞定位表明,该基因编码蛋白定位在细胞质膜上;继而对部分转GhHAK1基因拟南芥纯合系进行K+营养试验,发现在低钾(0.05 mmol/L)条件下,野生型拟南芥表现明显的缺钾症状,叶片黄化,植株抽薹明显受抑制,而转基因材料则表现植株叶片生长正常,抽薹未受影响,同时转基因拟南芥叶片中K+含量约为野生型拟南芥的2倍左右,根中K+含量约为1.5倍左右。该结果初步表明GhHAK1基因具有介导植株钾高效吸收的功能,为进一步培育适应土壤钾素匮乏及盐渍化环境下生长的棉花新品种提供重要的基因资源。

Cloning and Fuctional Characterization of a Potassium Absorption Related Gene GhHAK1 from Cotton (Gossypium hirsutum L.)

Cotton is an important economic crop typically with preference for potassium. Its yield and quality are closely related to potassium content. In this study, open read frame of GhHAK1 was cloned from the upland cotton. The dendrograms of GhHAK1 showed that it belonged to theⅠsubtribe, which was considered to be an important component of high-affinity system for K+. The trans-membrane region prediction reveals that the protein coded by this gene with 12 trans-membrane domains (TMS), and it had a long cytoplasmic ring between the second and third TMS. The sub-cellular localization experiment of onion epidermis showed that GhHAK1 was located on plasma membrane. And under the condition of low potassium (0.05 mmol/L) condition, the wild-type Arabidopsis showed obvious symptoms of K deficiency, the leaves turned yellow and bolting was obviously inhibited. But the transgenic plants growth was not affected. Besides, the content of K+ in transgenic Arabidopsis leaves was double that of the wild type and the content of K+ in root was about 1.5 times. The results showed that GhHAK1 might possess efficient potassium absorption function and would provide important genetic resources for further breeding new cotton varieties adapted to potassium deficiency soil and saline environment.