Study Of Increasing The Senescence-resistant Ability Of Xinjiang Cotton By Ipt Gene

Cotton is the important economic crop. As the biggest area of cotton growthing in China, Xinjiang province lost 10% to 15% of cotton because of senescence prematurely every year. Sometimes, the number is 25% eventually. And more than this, the premature senescence maybe cause cotton flowering abnormally. Thus it is important to increase cotton's senescence-resistance in order to improve its production and quality. People have found that using exogenous cytokinin can help plant resisting senescence, but its use is limited because the cost of producing cytokinin extent generously for its complex structure.The main gene of using genetic engineering technology to change density of cytokinin of plant is isopentenyl-transferases(ipt) gene. However, it will be bad for plant if the gene expressing continually for example slow growth, plant dwarf, infertility seeds, without roots and so on. So, we should choose suitable promoter to regulate the expression of ipt gene.Our study used cold-inducible promoter PRD29A,PCBF3 and senescence-inducible promoter PSAG12 which come from Arabidopsis thaliana to regulate the expression of ipt gene. And we constructed three plant express vector(pBI121-PRD29A-ipt, pBI121-PSAG12-ipt, pBI121-PCBF3-ipt).By the observation of transgenic tobaccos we found that transgenic tobaccos decreased apical dominance but improved lateral bud growing and inhabited root elongation comparing with wild-type tobaccos. When transplanted transgenic tobaccos outdoor, they grew better than wild-type tobacco for example bigger leaves and higher content of chlorophyll. Despite they had lateral bud, they could grow normally. We conformed the regulation effect of promoter controlling ipt gene by the analysis of transgenic tobaccos, and by doing this we could have a good use of the constructed vector.The main way of transforming cotton is pollen-tube-pathway method, but this way waste time and power and limit the efficiency of cotton transforming. By this we set up the system of cotton regeneration. Induce cotton hypocotyl growing embryo-callus, then induce growing buds, and in the end grow roots so regenerate seedlings. We dip hypocotyl by Agrobacterium tumefaciens and induce regenerating cotton seedlings.Our study confirmed the use of expression system by transforming tobacco, which set up the background for further use to cotton. At the same time we constructed the regeneration system of cotton, which is useful for transforming cotton, get rid of disadvantage of pollen-tube-pathway method and save lots of time and power. Our study has important meaning for the research of increasing the ability of Xinjiang cotton.