Transformation Of TaPHR1Gene And Genetic Analysis Of Transgenic Wheat

Phosphorus, one of the essential elements for plant, is often a limiting nutrient because ofits low availability and mobility in soils. Significant changes in plant morphology andbiochemical processes are associated with Pi deficiency. Wheat is one of the most importantcrops in the world, and the difference of phosphorus efficiency among different wheatgenotypes are highly significant. Exploration and utilization of the genetic resources of highefficient phosphorus nutrition in wheat are the key to sustainable agricultural development. Atthe same time, genetic transformation is a valuable tool for direct crop improvement andfunctional genomics study. Unfortunately, wheat is considered as a recalcitrant plant togenetic transformation due to its low efficiency and genotype dependency.Mature embryos of Tangnong18and Jimai22were used to study the influence factors ofthe tissue culture and the transformation mediated by A. tumefaciens. Based on this technique,TaPHR1gene had been integrated into the genome of wheat variety Jimai22. Then, Jimai22and its transgenic plant had been adopted in present research work for investigating plantgrowth, morphological characters of root and phosphorus nutrition characteristics of wheatseedlings under different phosphorus supply in the hydroponic culture system. The mainresults of the research are as follows:1. The imbibition time, concentration of plant growth regulator and so on wereimportant influence factors for the induction, differentiation and regeneration of wheat matureembryos callus, and the optimal system was estbilshed. In this research, the most appropriateconcentration of2,4-D and KT were2.0mg/L and5mg/L, the optimal imbibition time was16hours.2. The A.tumefaciens cell density, inoculation duration, co-cultivation conditions and soon were important influence factors for transformation of wheat mature embryos，and theoptimal system of genetic transformation mediated by A.tumefaciens was preliminarilyestablished. In this research, the best transformation parameters were：OD600=0.6of bacterial density，30minutes infection with A.tumefacienens，3days co-cultivation with the filter paperon the surface of medium。3. Using the system of transformation, the over expression vector pTaPHR1, whichcontaining the gene TaPHR1and NPTⅡ, was introduced into wheat variety Jimai22byAgrobacterium strains LB4404. As a result, some transgenic wheat plants were obtained, andthey were proved that target gene have been integrated into the wheat genome by using PCRamplification and Southern blotting. At the same time, target gene was transmitted from theparent to the next generation, and the segregation pattern conformed to the Mendelian law.4. Under the hydroponic culture established in this research, when the Pi supply wasdeprived, the biomass, average root diameter, phosphorus concentration and content of wheatseedlings decreased dramatically, but the stress obviously increased the root/shoot ratio, totalroot length and uptake area, lateral root numbers, phosphorus uptake efficiency and utilizationefficiency were also changed. The variation tendency of different genotypes were similar, butthe amplitude of variation was remarkably different, the transgenic plant of Jimai22withmore TaPHR1gene which is got thought agrobacterium tumefaciens-mediated method hasstronger tolerance to phosphorus insufficiency.