棉花微管结合蛋白基因GhMAP1-LC3的克隆与表达分析

Cloning and Expression Analysis of GhMAP1-LC3 Gene from Cotton (Gossypium hirsutum L.)

应用RT-PCR从陆地棉（Gossypium hirsutum L．）石远321开花当天胚珠中分离到一个553bp的片段，含有一个360bp的开放读码框，推导的氨基酸序列（119个氨基酸）与水稻、拟南芥的MAP1-LC3（Microtubule-associated Protein 1-Light Chain3）分别具有94％与90％的同源性，由此推测该基因为编码棉花微管结合蛋白基因家族的一个成员，命名为GhMAP1-LC3。实时定量RT-PCR分析表明，该基因（GhMAP1-LC3）在棉花的胚根、叶片、花瓣、花药以及0—5DPA（开花后天数）胚珠、10-25DPA纤维中均有表达，其中以20DPA纤维中的表达量最高，而在下胚轴、-3DPA胚珠、30DPA纤维与35DPA纤维中没有表达。基于其表达模式以及对其他物种MAP1-LC3蛋白的认识，推测其对纤维初生壁的形成起着重要作用。

Using RT-PCR, a fragment of cDNA was obtained from the ovules of cotton （ Gossypium hirsutum L. ） cv. Shiyuan 321 at 0 DPA （days post anthesis）. The sequence of 553 bp, containing an open reading frame of 360 bp was deduced to encode a polypeptide of 119 amino acid residues, which shared 94% and 90% homology with the light chain 3 of microtubule-associated protein 1 （MAP1-LC3） from rice and Arabidopsis thaliana, respectively. Therefore, it seems that the cloned sequence represents the MAP1-LC3 gene in cotton, and it was named GhMAP1-LC3. The expression profile of the gene was analyzed by real-time quantitative RT-PCR. The results indicated that it was expressed in the ovule of 0-5 DPA and in the fiber of 10-25 DPA. In other cotton tissues, such as radicle, leaf, petal, anther, the transcript of GhMAP1-LC3 was also detected. The expression of GhMAP1-LC3 reached its peak in the fiber on 20 DPA. But the transcript of GhMAP1-LC3 was not detected in the fiber on 30 and 35 DPA, nor in the ovule on - 3 DPA and in hypocotyls. Based on the expression profile of GhMAP1-LC3 and the function of MAP1-LC3, it was suggested that GhMAP1-LC3 play an important role in the formation of the primary wall of cotton fiber.