Cloning And Characterization Of QLOP2、qPSR2-1,A Major Cold Tolerant QTL From Dongxiang Wild Rice

Cultivated rice (Oryza sativa L.) is one of the most important crops in the world, after corn and wheat, because of its relatively small genome, genetic transformation system mature and collinearity with other crops, making it a plant molecular genetics and genomics research model plant. In recent years, rice seedling chilling caused plant growth delay and death, which has became a natural disaster that affecting stable food production around the world. Therefore, mining cold-tolerant germplasm, identifying molecular mechanism of cold tolerance and providing reliable quantitative trait loci (QTL) for molecular marker-assisted selection are important for enhancing rice tolerance and ensuring food safety.In this study, leaf osmotic potential and seedling survival of two cold tolerance indicators are used. A mapping population consisting of 151 BC2F1 plants was constructed by using Dongxiang wild rice(Oryza rufipogon Griff.) as a donor parent and chilling-sensitive indica as a recurrent parent. Through development of polymorphic molecular markers and a large segregating populations of 8324 BC4F2, qLOP2 and qPSR2-1 were co-located to a 39.3-kb candidate region. Based on Nipponbare physical map in the RAP 1.0 database, Os02g0677300 exists in this candidate region.After comparison and analysis, the gene belongs to AP2/EREBP family DREB transcription factor, which plays an important role in the regulation of plants to low temperature, hormones, pathogens, drought, high salinity and other abiotic stress responses. In this study, through transgenic tissue culture technology, using Agrobacterium-mediated to transfer to indica R6547 mature embryos in order to obtain transgenic resistance to cold material. Finally, we get To transgenic plants 66, by PCR, a total of 45 positive transgenic plants, conversion rate is 7.35%.At low temperature stress, rice membrane system is damaged, chlorophyll synthesis is inhibited, chloroplast structural is damaged, which leads to decreased photosynthetic ability, relative water content in cells is also decreased. The free proline content in plants can be significantly increased under stress conditions, which reflects the resistance of plants. If the determination of the above physiological indicators that can effectively respond to the situation of plants resistant to cold. So the Tj generation of transgenic plants were physiological testing, the results show that, T1 transgenic plants in the survival rate, chlorophyll content and fluorescence value, relative water content and proline content were higher which shows the gene plays an important role. This study reveals the molecular mechanism of cold tolerance in rice and provides a theoretical basis for further regulatory pathways research at seedling stage.