茶树水通道蛋白基因的克隆与表达分析

从茶树中克隆了6个水通道蛋白(aquaporin,AQP)基因的cDNA全长序列,根据序列相似性和系统进化分析结果,分别命名为CsNIP1;1、CsNIP5;1、CsPIP2;1、CsPIP2;2、CsTIP1;1和CsTIP2;2。氨基酸序列特征分析表明,6个基因的编码氨基酸序列长度在250~301个氨基酸残基,分子量在25.186~30.728kD之间;均为疏水性蛋白,并都含有6个跨膜螺旋;6个基因均含有MIP蛋白家族的特征序列HF/I/VNPA/SI/L/VTI/FA/G和NPA(Asn-Pro-Ala)基序,以及类似沙漏状的跨膜三级结构。荧光定量PCR分析显示:这6个基因在根、茎、叶和花中均表达,且在根中的表达水平最高,表明它们与茶树根系的物质转运密切相关;CsAQPs基因的表达受ABA、高盐、干旱和低温胁迫的调控,表明它们可能参与茶树抗逆响应。

Cloning and Expression Analysis of Aquaporin Protein Genes in Tea Plant (Camellia sinensis)

The full length of cDNA of six CsAQP genes were cloned from tea plant, and named as CsNIP1;1, CsNIP5;1, CsPIP2;1, CsPIP2;2, CsTIP1;1 and CsTIP2;2, respectively, based on the phylogenetic analysis and sequence similarity.Amino acid sequence characteristics analysis showed that their amino acid residues length are ranged from 250 to 301, and those of molecular weight are ranged from 25.186 to 30.728 kD. All CsAQPs are hydrophobic proteins, and have 6 transmembrane helices in each member. Moreover, they are conserved on the characteristic sequence HF/I/VNPA/SI/L/VTI/FA/G, the two NPA (Asn Pro Ala) motifs, and the hourglass fold of MIP protein family. The real time RT PCR results showed that six CsAQPs were ubiquitously expressed in roots, stems, leaves and flowers, whereas all of them had the highest level in roots, indicating that they might be closely related to the regulation of water transport in the roots of tea plant. The expression patterns of CsAQPs were modulated by ABA, salt, drought and cold treatments, demonstrating that they are involved in the tea plant response to abiotic stress.