大麦阶段性低温诱导白化突变体的转录组分析

Transcription Analysis of Stage Specific Low Temperature Induced Albinism in Barley

叶色突变体是研究叶绿素代谢、叶绿体发育和光合作用的重要材料。本研究从大麦鄂啤2号(野生型)7Li离子突变体库中筛选获得一份大麦阶段性低温诱导白化突变体(SLTW),该突变体受低温诱导后,于五叶期叶片开始出现白化现象,温度升高后于拔节期逐步恢复为绿色。与野生型相比,该突变体叶片中叶绿素a、叶绿素b和类胡萝卜素含量均显著下降。SLTW突变体与野生型的转录组比较分析表明,差异表达基因显著富集到类胡萝卜素合成、四吡咯结合、血红素结合、铁结合、氧化还原过程、光合作用等通路上。叶绿素合成基因(ID号为HORVU.MOREX.r2.2HG0174230)和类胡萝卜素代谢基因(ID号为HORVU.MOREX.r2.5HG0354290)在SLTW突变体与野生型中的表达量均差异显著,且均检测到SNP突变,推测这些基因可能与大麦阶段性白化有关。编码光合作用-天线蛋白、细胞色素P450、跨膜转运(ABC转运)蛋白及转录因子也可能是调控大麦阶段性白化的潜在候选基因。

Leaf color mutants are important materials for studying chlorophyll metabolism, chloroplast development and photosynthesis. A stage specific low temperature induced white leaf(SLTW) mutant was derived from the barley mutant library, which was constructed by treating Epi 2(wild type) with ~7Li-ion beams. Leaf color of the mutant began to turn into albinism at the five-leaf stage induced by low temperature, and gradually returned to green at jointing stage. Comparing with wild type, the content of chlorophyll a, chlorophyll b, and carotenoids in the SLTW mutants were significantly lower than those of the wild type. Transcription analysis of the SLTW mutant and wild type indicated that, Differentially expressed genes were significantly enriched in the carotenoid biosynthesis, tetrapyrrole binding, heme binding, iron ion binding, oxidation-reductase process and photosynthesis, etc. Chlorophyll biosynthesis related gene(ID:HORVU.MOREX.r2.2HG0174230) and carotenoid metabolism related gene(ID:HORVU.MOREX.r2.5HG0354290) showed significant differences between SLTW and wild type, and SNP mutations were also detected. They were the putative genes, responsible for stage specific low temperature induced albinism. Genes encoding photosynthesis-antenna protein, cytochrome P450,membrane transport(ABC transport) protein and transcription factors may also be the candidate genes for regulating stage specific low temperature induced albinism.