水稻淡黄叶突变体xws的光合特性与基因定位

为了解析水稻叶绿体发育和高光效育种中光合作用的机理,本研究以不育系P88S群体中发现的一株淡黄叶自然突变体xws为试验材料,对该突变体进行表型鉴定和光合特征分析,并对其进行精细定位和候选基因分析。结果表明,xws在整个生育期叶片、茎和穗均呈淡黄色。与野生型相比,xws叶片、茎和穗的叶绿素a、叶绿素b和类胡萝卜素含量均显著下降。透射电镜观察结果发现,与野生型相比,xws嗜锇小体消失,类囊体数量减少。xws的净光合效率、气孔导度、蒸腾速率、胞间CO₂浓度和叶绿素荧光参数与野生型相比均降低。以xws与R032杂交的F₂群体作为定位群体,将基因精细定位至水稻第3号染色体分子标记WY242和WY119之间,其物理距离为51.7 kb。本研究结果为进一步研究水稻叶绿体发育,从而提高水稻光合作用和分子调控网络途径提供了理论支撑。

Photosynthetic Characteristics and Gene Mapping of Pale Yellow Leaf Rice Mutant xws

In order to analyze the mechanism of photosynthesis in rice chloroplast development and high light efficiency breeding, a pale yellow leaf mutant xws which was found in P88S, a sterile line, was used as the test material in this study. The phenotypic identification and photosynthetic characteristics of the mutant, and fine mapping and candidate gene analysis were performed. The results showed that the leaves of xws displayed faint yellow throughout the growth periods, and its stems and spikes also showed yellow. Compared with the wild type, the content of chlorophyll a, chlorophyll b and carotenoids in the leaves, stems and spikes of xws were decreased significantly. Transmission electron microscopy showed that the osmophilic bodies were disappeared and the number of thylakoids was decreased in the mutant compared with the wild type. The net photosynthetic efficiency, stomatal conductance, transpiration rate and intercellular CO₂ concentration of xws were all decreased compared with that of the thewild type, and the chlorophyll fluorescence parameters also decreased. With the F₂ population derived from xws and R032 as the mapping population, the gene was finely mapped between molecular markers WY242 and WY119 on chromosome 3, with the physical distance of 51.7 kb. The results will be helpful for further researches on rice chloroplast development and provide theoretical support for improving rice photosynthesis and molecular regulation network.