论文部分内容阅读
水稻(Oryza sativa)起源于热带,随着人们对粮食需求的增长其种植区不断向北扩展,这就要求选择耐冷能力强的水稻品种。但是目前,对水稻耐冷性的分化及其机制的研究尚少见报道。本研究以辽宁、江苏和广东3个不同气候地区水稻为实验材料,通过冷害症状及叶绿素荧光指数比较水稻耐冷性差异,采用DNA甲基化亚硫酸盐测序法(bisulfite sequencing PCR,BSP),研究CBF(C-repeat binding factor)冷响应转录通路的ICE1(inducer of CBF expression 1)基因区域与启动子区域甲基化水平影响不同品种水稻冷害差异的分子机制。结果表明ICE1基因区域甲基化水平无差异,但是启动子区域甲基化有显著差异(P<0.05)。辽宁丹粳17(LN004)的ICE1基因启动子区域2个胞嘧啶被甲基化,耐冷指数最高;江苏的南粳5055(JS013)的ICE1基因启动子区域7个胞嘧啶被甲基化,耐冷指数居中;广东的粤新占2号(GD008)的ICE1基因启动子区域11个胞嘧啶被甲基化,耐冷指数为最低。定量PCR检测结果显示,ICE1和其下游调控的CBF1(C-repeat DRE binding factor 1)、CBF3(C-repeat DRE binding factor 3)的基因表达量与耐冷性显著正相关(P<0.05),但是与ICE1启动子区域甲基化水平显著负相关(P<0.05)。这表明辽宁(LN004)、江苏(JS013)和广东(GD008)水稻的耐冷性与地区气候相适应,且耐冷性受ICE1基因甲基化水平决定的CBF冷响应转录通路调节。本研究结果为进一步解释水稻耐冷的分子机制提供了理论依据。
Oryza sativa, which originated in the tropics, continues to expand northward as people demand more food, which requires the selection of rice varieties that are resistant to cold stress. However, at present, the research on the differentiation of cold tolerance and its mechanism in rice is seldom reported. In this study, rice from three climatic regions of Liaoning, Jiangsu and Guangdong were used as experimental materials. The cold tolerance and chlorophyll fluorescence index were used to compare the cold tolerance of rice, and the DNA methylation bisulfite sequencing (BSP) CBF (C-repeat binding factor) cold-responsive transcriptional pathway ICE1 (inducer of CBF expression 1) gene promoter region methylation levels affect different types of rice cold damage molecular mechanism. The results showed that there was no difference in the ICE1 gene methylation level, but the promoter methylation was significantly different (P <0.05). Two cytosines were methylated in the promoter region of ICE1 gene in Danjing 17 (Liaoning Province), and the highest cold tolerance index was found. Seven cytosines in ICE1 promoter region of Nanjing Japonica 5055 (JS013) were methylated and resistant to cold The index was in the middle; 11 cytosines were methylated in ICE1 gene promoter region of Guangdong Yuexinzhan 2 (GD008), with the lowest cold tolerance index. Quantitative PCR results showed that the gene expression level of ICE1 and its downstream C-repeat DRE binding factor 1 and CBF3 (C-repeat DRE binding factor 3) were significantly and positively correlated with cold tolerance (P <0.05) There was a significant negative correlation with ICE1 promoter methylation (P <0.05). This indicates that the cold tolerance of rice in Liaoning (LN004), Jiangsu (JS013) and Guangdong (GD008) is compatible with the regional climate and the cold tolerance is regulated by the CBF cold-responsive transcriptional pathway determined by the ICE1 gene methylation level. The results provide a theoretical basis for further explaining the molecular mechanism of cold tolerance in rice.