柳枝稷质膜型水通道蛋白基因PvPIP1的克隆和序列分析

利用同源克隆结合RACE技术从柳枝稷（Panicum virgatum）中克隆得到了cDNA全长为1215bp的柳枝稷质膜型水通道蛋白基因（PvPIP1），包含867bp开放阅读框序列，编码288个氨基酸，将该基因提交到GenBank，获得登录号KC955176。生物信息学分析表明PvPIP1基因分子量为30.78kD，含有6个跨膜区，2个高度保守的NPA模体结构，存在PIPs的高度保守序列GGGANXXXXGY和TGI/TNPARSL/FGAAI/VI/VF/YN。对其同源性的分析表明，PvPIP1基因与黑麦草（Lolium perenne）和大麦（Hordeum vulgare）的质膜型水通道蛋白同源性高达98%和93%。荧光定量PCR结果显示，在PEG胁迫的任何时间点PvPIP1基因的表达与对照相比都表现上调，在ABA和NaCl胁迫的9h内其相对表达量高于对照，推测PvPIP1基因可能参与柳枝稷对逆境的抗性反应。研究结果将为今后进一步探讨该基因在非生物逆境胁迫中的作用提供依据与信息。

Cloning and Sequence Analysis of the Plasma Membrane Aquaporins Gene PvPIP1 in Switchgrass

The full-length cDNA sequence of PvPIP1 was obtained from switchgrass 'Alamo' by the rapid-amplification of cDNA ends 3' and 5' RACE technology. Physicochemical properties and molecular features of PvPIP1 were predicted by bioinformatics approaches. The full-length cDNA sequence (GenBank Accession No. KC955176) was 1215 bp in length, containing a 867 bp open reading frame (ORF) encoding a 288 amino acids (30.78 kD). Bioinformatics analysis revealed that PvPIP1 gene exhibited a typical structure with six membrane-spanning domains and an internal symmetry showing two highly conserved Asn-Pro-Ala (NPA) motifs, and possessing the PIP family signal consensus sequence GGGANXXXXGY and TGI/TNPARSL/FGAAI/VI/ VF/YN. Similarity alignment of plant demonstrated that amino acids showed high identity with LpAQP (98%) and HvAQP (93%). The expression of PvPIP1 was up-regulated in all time points under PEG stress and the relative expression levels were significantly higher than those of control within 9 h of ABA and NaCl stress. This result indicated that PvPIP1 might play an important regulation role under stress in switchgrass. These results provided important information for further studies on molecular regulation mechanism underlying abiotic stress resistance in switchgrass.