谷子黄叶色突变体ylm-1的精细定位与功能分析

Fine Mapping and Functional Analysis of Yellow Leaf Mutant ylm-1 in Foxtail Millet

谷子叶色突变体在研究C_(4)光能利用效率和叶绿素代谢机制方面具有重要作用。为探究谷子叶色突变的分子机制,利用甲基磺酸乙酯(EMS)处理谷子品种豫谷1号,获得1个稳定遗传的黄叶色突变体ylm-1。通过表型和遗传分析及遗传背景检测,同时利用突变位点图谱(MutMap)技术对突变基因进行精细定位。结果表明,ylm-1整个生育期叶色均为淡黄色;ylm-1与野生型遗传背景相同且受1对隐性核基因控制;MutMap精细定位到第9号染色体关联区间内共13个非同义突变基因,其中,Seita.9G249900是一个编码与红叶绿素代谢还原酶(RCCR)相关的基因,该基因位于第9号染色体19937988与19940620bp之间,含有2个外显子和1个内含子,在第2外显子361bp处发生A/T碱基突变,导致1个谷氨酸(E)变成天冬氨酸(D)。根据突变碱基设计了dCAPS标记,进一步验证了ylm-1候选基因突变位点。黄叶色突变体ylm-1的鉴定与基因功能分析将为该基因的有效利用、功能验证及作用机制研究奠定理论与技术基础。

Leaf color mutants play an important role in investigating the utilization of C_(4) light energy and the mechanism of chlorophyll metabolism in foxtail millet.To study the molecular mechanism of the leaf color mutant in foxtail millet,we identified a stable mutant ylm-1 from the library generated by treating Yugu 1 with ethyl methanesulfonate(EMS).The mutant was studied by phenotype identification,genetic analysis and genetic background identification.At the same time,the mutated gene was mapped quickly and precisely using a mutation map(MutMap).The results showed that ylm-1 displayed a yellow leaf phenotype throughout the growth phase.ylm-1 had the same genetic background as the wild type controlled by a recessive nuclear gene with genetic analysis.The association interval contained 13 non-synonymous mutant genes in the ninth chromosome by the MutMap procedure.Seita.9G249900 was one of the genes encoding a chloroplast associated red chlorophyll catabolite reductase whose physical position was between 19937988 and 19940620bp of the ninth chromosome and contains two exons and one intron.An A/T base mutation occurred at 361bp in the second exon,resulting in a glutamate(E)changing to an aspartic acid(R).The mutation site of the candidate gene in ylm-1 was further verified by the dCAPS marker.The identification and gene functional analysis of a new yellow leaf mutant ylm-1,which will provide a theoretical and technical basis for the effective use,the study of the functional evidence and the mechanism of action of the gene in foxtail millet.