中文摘要：

水通道蛋白（aquaporin,AQP）是位于生物膜上的一类古老的通道蛋白,能够高效地运输水分,在整个植物生长发育过程中发挥重要作用.本研究从棉（Gossypium hirsutum）纤维细胞中分离出1个编码水通道蛋白的基因,该基因序列中有3个内含子和4个外显子,开放阅读框为837 bp,编码一个含278个氨基酸残基的多肽.序列比对和进化分析表明该基因与烟草NtPIP2;1同源性最高（86％）,属于PIP2水通道蛋白,将该蛋白编码的基因命名为GhAQP2（GenBank登录号：KJ920936）.利用半定量RT-PCR对GhAQP2基因在棉花不同器官和不同发育阶段纤维中的表达模式进行分析,发现该基因在纤维细胞中优势表达,其表达量在开花后随着纤维的发育逐渐升高,在开花后6～18d的纤维细胞中持续高表达,然后下降.将GhAQP2基因转化BY-2烟草（Nicotiana tobacum）悬浮细胞对其功能进行初步分析,发现该基因在BY-2细胞中过量表达使细胞形态发生显著变化,由圆球状变为长条状,且细胞由聚集变为松散状态.这些结果提示GhAQP2可能在棉花纤维伸长过程中起重要作用.

英文摘要：

Aquaporins（AQPs） are ancient channel proteins localized in biological membranes and facilitating water transport through cell membranes rapidly.Aquaporins play an important role in plant development.A gene encoded aquaporin was isolated from cotton （Gossypium hirsutum） fiber and named GhAQP2 （GenBank accession No.：KJ920936）.The full length of GhAQP2 composed three introns and four exons,and contained a open reading frame of 837 bp encoding 279 amino acids.Analysis of multiple alignment and phylogenetic tree showed that GhAQP2 shared the highest identity with NtPIP2; 1（86％） and belonged to PIP2 protein family.Semi-quantitative RT-PCR was used to investigate the expression profile of GhAQP2 in different tissues and fibers from different days post-anthesis.The results showed that GhAQP2 was preferentially expressed in cotton fiber,and the transcript level increased along with fiber development and maintained at high abundance in fiber cells at 6 to 18 days post anthesis,after which time it gradually decreased.The GhAQP2 was transformed into tobacco （Nicotiana tobacum） suspension BY-2 cells to preliminary analyze the gene function.Overexpression of GhAQP2 in BY-2 cells led to cell shape significantly changed from round to long strip,and the cell state changed from aggregating to loose.All our results manifested that GhAQP2 may have important effect on the elongation of cotton fiber cell.