| In this study,three extreme drought resistant cotton varieties and three extreme drought sensitive cotton varieties were used as experimental materials.The expression of UDPGP gene and APX gene in Gossypium hirsutum under 15% PEG-6000 stress at different time and space was detected by q RT-PCR.The main genes responding to drought stress were screened,and the key genes in these two families were sequenced to understand their structures At the same time,plant expression vectors and silencing vectors of the two genes were constructed and transferred into different varieties of cotton materials.After detection and verification,the positive transgenic plants were subjected to soil drought stress at seedling stage to explore the drought resistance function of the two genes.The results are as follows:1.Under 15% PEG-6000 stress,GhUDPGP10 and GhAPX07 genes were up-regulated in the two cotton varieties with different resistance.Although there were differences between the two gene expression patterns,the gene expression in drought resistant cotton varieties was significantly higher than that in drought sensitive cotton varieties.The expression of GhUDPGP10 gene and GhAPX07 gene was dominant at 12 h and 3 h after 15% PEG-6000 stress,and the expression of GhUDPGP10 gene was more stable than that of GhAPX07 gene.This indicated that there was a close relationship between the expression of GhUDPGP10 gene and GhAPX07 gene and the response of cotton seedling to drought stress.2.The CDS regions of GhUDPGP10 gene and GhAPX07 gene were cloned and sequenced from the c DNA strand of cotton leaves under drought stress for 12 h in Xin Lu Zhong 36.The results showed that both GhUDPGP10 gene and GhAPX07 gene encode hydrophilic proteins without signal peptide region and transmembrane region,and their secondary and tertiary structures are similar to UDPGP protein and APX protein,indicating that GhUDPGP10 gene and GhAPX07 gene are members of UDPGP gene family and APX gene family respectively.3.The plant expression vector and virus silencing vector of GhUDPGP10 gene were successfully constructed and transferred into cotton.The results showed that: under the same drought stress conditions,the leaf wilting and curling degree of the over expressed non transgenic plants were more obvious than that of the transgenic plants,the stem water loss and shrinkage degree were more serious,and the dry death time was relatively early;Compared with the normal plants,the silent plants would have the phenomenon of leaf wilting and curling,stem shrinkage and dry death at an earlier time.These results indicate that GhUDPGP10 gene is indeed involved in the response process of cotton to drought stress.4.The plant expression vector and virus silencing vector of GhAPX07 gene were successfully constructed and transferred into drought sensitive and drought resistant cotton materials respectively.The results showed that the transgenic plants with overexpression had better tolerance to drought stress than non transgenic plants under the same conditions,However,the drought stress adaptability of silent plants decreased significantly,and the plants appeared the phenotype of dry death earlier.These results suggest that GhAPX07 gene is involved in the response of cotton to drought stress. |
