| Self-incompatibility and male sterility are two main approaches to produce hybrids in crops.For the self-incompatibility approache of hybrid production,pepole have to face the troublesome problems such as artificial bud pollination for the propagation of self-incompatibility lines, vigor degeneration due to the successive self-cross as well as hard to achieve100%purity of hybrid, so it results in higher cost of production hybrids. Therefore, it is more popular for using male sterile line to produce hybrid seed. Mustard (Brassica juncea) is a kind of important cruciferous vegetables,and mustard is a highly self-compatible crop, so the male sterile line is very important for the production of mustard hybrids.With the rapid development of modern biotechnology, generation male sterility through genetic engineering techniques have became a hot topic in plant male sterility research, and the mechanism behind cytoplasmic male sterility (CMS) attract more researcher.In present, the viewpoint that the genes related with CMS located on chloroplast genome and mitochondrial genome is accepted generally. Due to no direct evidence demonstrate that chloroplast genome mutation will lead to CMS, so researchers have generally considered the mitochondrial genome variation will lead to CMS. A few reports showed there are a few gene such as MSH1, RECA3, and OSB1on nuclear genome which are responsible for the stability maintain of mitochondrial genome. The suppressed or function lose of these genes will cause mitochondrial genome rearrangements occurring, which may lead to phenotype changes, even cytoplasmic male sterility produce. Among the three genes, MSH1is considered the the most important gene for the maintain of mitochondrial genome stability,However, There’s little study about MSH1gene in plant is reported in China,and let alone a study in mustard crop.There are reports have shown MSH1is not only affect the CMS, but also have influence plant phenotypic changes, such as delayed flowering, increased chlorophyll content..This study take the "Yu Feng" mustard as target material to study the impact on phenotypic changes of mustard by MSH1gene RNAi. The purpose of this study is to generate non-transgenic mustard cytoplasmic male sterility, delayed flowering mustard, photosynthetic capacity improved mustard. The results are as follows:1.A687bp fragment of MSH1gene was cloned from Brassica cDNA, the sequence similarity is98%comparied with the spliced Brassica oleracea MSH1gene sequence based on sequence data of BRAD.And the sequence homology is95%comparied with the fragment from mustard genome. Take the687bp fragment as the interfering target region of MSH1mRNA, a RNAi vector pCA13BarMSH1RNAi of MSH1gene were constructed, which contains a Bar gene as the marker gene for the transgenic plants selection by using herbicide PPT.2.The RNAi vector of pCA13BarMSH1RNAi was transformed into mustard by Agrobacterium-mediated genetic transformation. Total7transgenic plants with resistance to herbicide PPT were generated. The further PCR identification indicated the MSH1RNAi gene had been introduced into the mustard genome.3.No male sterile phenotype was observed on7To transgenic plants. However, more branchses or dwarfing were observed on several plants.Transgenic plants m-2,m-3,m-5and m-7generated more branchses, m-6plants showed dwarfing phenotype,but no any changes were observed for m-1and m-4transgenic plants.4.The T1generation of7MSH1RNAi transgenic plants were obtained by self-cross,but no phynotype abnormal were observed on seedling stage. |
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