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通过EMS(ethane methyl sulfonate)诱变籼稻品种IR64获得一个稳定遗传的显性斑点叶突变体HM113。在大田环境下,突变体褐色斑点在播种后3周的叶片上产生,始穗期扩散至叶鞘。与野生型IR64相比,突变体HM113的株高、结实率和千粒重等农艺性状显著下降,光合色素含量、净光合速率和可溶性蛋白含量显著降低。同时突变体CAT和SOD活性显著降低,POD活性显著上升。组织化学分析显示,突变体叶片中积累了大量活性氧,且斑点处细胞坏死。白叶枯病菌接种结果显示,HM113是一个广谱抗性增强的突变体。实时定量PCR分析表明HM113中防卫反应基因AOS2、PAL4、PR10和PR1b等的表达大幅上调。遗传分析表明,突变体褐斑性状受单显性基因(SplHM113)控制,利用图位克隆法将该基因定位在第7染色体长臂RM21605和RM418之间,物理距离约为308 kb。本研究为褐斑基因Spl~(HM113)的克隆与功能分析奠定了基础。
A stably inherited dominant spot leaf mutant, HM113, was obtained by inducting indica rice variety IR64 with ethane methyl sulfonate. Under field conditions, mutant brown spots were produced on the leaves of 3 weeks after sowing, beginning with the leaf sheath. Compared with the wild-type IR64, the agronomic traits such as plant height, seed setting rate and 1000-grain weight of mutant HM113 significantly decreased, and photosynthetic pigment content, net photosynthetic rate and soluble protein content decreased significantly. At the same time, the activities of CAT and SOD were significantly decreased and POD activity was significantly increased. Histochemical analysis showed that a large amount of reactive oxygen species accumulated in the mutant leaves, and the cells at the spots were necrotic. Bacterial blight inoculation results showed that HM113 is a broad-spectrum resistance-mutated mutant. Real-time quantitative PCR analysis showed that the expression of defense response genes AOS2, PAL4, PR10 and PR1b in HM113 and the like were significantly up-regulated. Genetic analysis showed that the brown spot trait was controlled by a single dominant gene (SplHM113). The mapped gene was located between RM21605 and RM418 on the 7th chromosome using the map-based cloning method with a physical distance of about 308 kb. This study laid the foundation for the cloning and functional analysis of the brown spot gene Sp1 ~ (HM113).