Resistance Expression Of Bar-transgenic Wheat And Analysis Of Their Compositive Traits

This paper mainly focus on the research of bar gene's resistance to PPT and how transgene of bar affects the agricultural characteristic of transgenic wheat. Main results as following:Introducing bar gene into wheatIn this paper, lines of wheat containing bar gene were obtained from bombarded transformation and the sexual transfer of the transgene. In crossing experiments, the transgenic lines L34 and L28 which contains bar gene were crossed with different non-transgenic females-wanmai48 and yangmai87158, and then progeny of BC2 were screened by PPT resistance detect and PCR analysis. This indicates that it is possible to transform transgene successfully via sexual way into non-transgenic genotypes. Therefore, it will shorten the period of wheat breeding if the sexual transfer of the transgene method (STTM) is applied combined with molecular breeding methods, such as bombarded transformation and Agrobacterium tumefaciens-mediated transformation.PPT resistance detectTo understand PPT resistance of transgenic lines, some analysis methods and resistance parameters were adopted. In this research, seed bioassay method was applied because of its advantage, such as shorter period, lower cost and simpler manipulation.GS activity in leaf decreased evidently after PPT treatment. Furthermore, water lost from the leaf of samples. GS activity of transgenic lines also reduced remarkably when they were treated with PPT, but it restored in short time. It suggests that toxicity of PPT could be eliminated by PAT which is product of bar gene.PAT activity assay indicated that the lines transformed by bombard had higher PAT activity than those lines obtained from STTM. Among the progeny BC1, BC2 obtained from STTM, some lines had no PAT activity. The reason may contribute to the separation of bar gene in plants.Effects of PPT on chlorophyll content in the leaves of wheatAfter treatment with PPT, chlorophyll content of the control decreased due to reduced GS activity in leaf, but transgenic lines'had small changes. This confirms that PPT can strongly limit the synthesis of chloroplast. Sensitivity to PPT of plant may be caused by failed synthesis chlorophyll in plant after treatment with PPT.Resistance heredity of bar geneObservation of bar gene's heredity characteristic was performed. Separation of bar gene in BC1 and BC2 obtained from the STTM accorded to Mendel's Laws of Inheritance. It shows that transgene of bar can be easily introduced into other varieties of wheat by STTM.Agricultural characteristic of wheat transformed with bar geneThe results of this experiment showed that agricultural characteristic of BC2 had no remarkable difference comparison to that of control, but T1 agricultural characteristic was inferior to control's. It suggests that the period of breeding could be shortened by application of molecular breeding methods combined with STTM.