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【目的】叶片是水稻进行光合作用的主要场所,叶片颜色的变化与水稻的生长发育直接相关。发掘水稻叶色突变体,是水稻功能基因组学研究的重要遗传基础。【方法】利用EMS诱变日本晴获得一个能稳定遗传的淡绿叶突变体,暂命名为pgl11(pale green leaf 11)。在不同生育期测定野生型与突变体的叶绿素含量。在苗期,取野生型与突变体叶片进行叶绿体结构的透射电镜观察。在分蘖期,测定野生型与突变体的光合参数并观察气孔结构。在成熟期,测定野生型和pgl11的主要农艺性状。以pgl11为母本,南京6号为父本构建相应的F2群体,采用图位克隆的方法,对该基因进行定位。【结果】从苗期开始,突变体pgl11的每一片新叶均表现为淡绿色,叶绿素含量显著降低,叶绿体发育异常。随着叶片的生长,叶色由淡绿逐渐转绿,至抽穗期时叶绿素含量亦无明显差异。pgl11还表现光合速率、气孔导度明显下降,胞间CO_2浓度上升。扫描电镜观察发现,突变体pgl11的气孔发育异常。与野生型相比,突变体的农艺性状如株高、剑叶宽、二次枝梗数、每穗粒数、粒长、粒宽、千粒重以及结实率等均显著降低。对叶绿素合成、光合作用以及质体发育相关基因的表达量测定表明,突变体pgl11中参与叶绿体转录和翻译相关基因的表达量显著升高,而叶绿素合成和光合作用相关基因的表达量显著下降。遗传分析表明,该突变表型受一对隐性核基因控制。通过图位克隆的方法将该基因定位于第1染色体上的C6和C8标记之间,物理距离约为110 kb。【结论】该定位区间内未见有叶色相关基因报道,推测PGL11基因可能是一个新的水稻叶色基因。
【Objective】 Leaf is the main site for photosynthesis in rice. The change of leaf color is directly related to the growth and development of rice. Discovery of rice leaf color mutants is an important genetic basis for functional genomics research in rice. 【Method】 A light green leaf mutant with stable inheritance was obtained by EMS mutation of Nipponbare and temporarily named pgl11 (pale green leaf 11). Determination of chlorophyll content in wild-type and mutant at different growth stages. At seedling stage, the leaves of wild-type and mutant were observed by transmission electron microscopy. At tillering stage, the photosynthetic parameters of wild-type and mutant were determined and the stomatal structure was observed. At maturity, the major agronomic traits of wild-type and pgl11 were determined. The F2 population was constructed with pgl11 as the female parent and Nanjing 6 as the male parent, and the gene was mapped by map-based cloning method. 【Result】 From the seedling stage, each new leaf of mutant pgl11 showed light green, chlorophyll content decreased significantly, and chloroplast developed abnormally. With the growth of leaves, the leaf color turned from light green to green gradually, and there was no significant difference in chlorophyll content at heading stage. pgl11 also showed photosynthetic rate, stomatal conductance decreased significantly, intercellular CO 2 concentration increased. Scanning electron microscopy showed that the stoma of pgl11 mutant was abnormal. Compared with the wild type, the agronomic traits of mutants such as plant height, flag leaf width, number of secondary branches, grain number per spike, grain length, grain width, grain weight and seed setting rate decreased significantly. The expression of genes involved in chlorophyll synthesis, photosynthesis and plastid development showed that the expression level of chloroplast transcripts and translation related genes in pgl11 mutant was significantly increased while the expression of chlorophyll synthesis and photosynthesis related genes decreased significantly. Genetic analysis shows that the mutant phenotype is controlled by a pair of recessive nuclear genes. The gene was located between the C6 and C8 markers on chromosome 1 by the map-based cloning method and the physical distance was about 110 kb. 【Conclusion】 There are no leaf color related genes reported in the mapping region. It is speculated that PGL11 gene may be a new leaf color gene in rice.