Improving Cotton's Ability Of Anti-drought Through Research On Aquaporins Genes Of Gossypium Hirsutum Leaf

Aquaporins refers to the water channel protein which lies on cell membrane and can selectively transfer water molecule effectively. It exists considerabIely in many kinds of animals, plants,microbe,etc. The transfer of free water which idmediated by aquaporins between different biomembranes is the main method of water in or out of cell. During the development of plant, gene expression of aquaporins with different code is connected with differnet physiological process, including the closeness of stomatal, the movement of organ, cell alongation and cell fission. What's more, aquaporins can also control the movement of water molecule between different membranes during the process of germination of seed, loading and unloading of phloem and stress response, so the water-selected channel in plant formed bu the aquaporins plays an important role in mediating the flowing of water molecule in or between cells, controlling the balance of water in plant and improving the ability of anti-salt and anti-drought.According to the current research in and abroad, only two kinds of aquaporins have been found in Gossypium hirsutum, they are plasma membrane intrinsic protein and tonoplast intrinsic protein. And former one only be found have expressed in the root, stalk and ovule but very rare in leaf. In this research, adopting the method of RT-PCR and according to the aquaporin gene's primer of Gossypium hirsutum published on the GenBank, we got four Gossypium hirsutum plasma membrane aquaporin genes by cloning. They are follows:GhPIPl;1, GhPIP1;2, GhPIP2;l and GhPIP2;2, and the testing sequence results show that the similarity between the sequences of these four genes and the published four is over 98%; what is more, the similarity between the sequences of amino acid is over 99%.Then expression vector pBI121-GhPIP has been constructured., and transferred into model plant tobacco mediated by agrobacterium. We have got transgenic tobacco. After preliminary RT-PCR analysis, we know that the transcription of transgenic plant is normal.In the study,300bp of four genes had been selected separately as the interference fragments to construct interference vector of RNA. Firstly, intermediate vector was constructed, then it was constructed on the expression vector pCAM2300 to transform the callus of embryo. After observing the growth condition of transformed callus, measuring the total weight of callus and the weight of callus without free water, the results of control group showed that callus' ability of controlling water had been improved. And this also showed that interference purpose had been achieved and the gene had been kept silence. The study has set foundation for the further study on similar gene.