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本研究通过筛选水稻籼型恢复系明恢86的组培变异后代,获得一个失控性细胞坏死突变体rcd1(runaway cell death 1)。结果显示:从苗期后期起,rcd1叶片出现橙黄色类病斑;分蘖期后,类病斑性状加剧;抽穗期后,类病斑串联成片,茎、叶、穗干枯,并衰亡。q RT-PCR分析表明,Os PR1b、Os NAC4、Os PAL1、Os CHT1、Os CHT3、Os POC1等病程相关基因在rcd1类病斑叶片组织中表达量明显高于其在野生型叶片组织中的表达水平。田间调查发现,rcd1突变体表现出对胡麻斑病抗性增强。遗传分析显示,rcd1突变性状由单一隐性核基因控制。利用93-11与rcd1配制的F2群体进行基因定位,将rcd1定位在水稻第12染色体着丝粒附近In Del标记ID7909和ID8337之间约428 kb的区间。测序及共分离分析发现,rcd1与SL基因等位。在rcd1突变体中,SL基因编码区发生G1205T的单碱基突变,导致第370位氨基酸Arg→Leu的变异。本研究结果可为更深入解析rcd1调控水稻类病斑形成及抗病应答机制奠定了基础。
In this study, runaway cell death 1 (rcd1) was obtained by screening the tissue culture mutant progenies of indica restorer line Minghui86 in rice. The results showed that: from the late seedling stage, rcd1 leaves appeared orange-yellow lesions; tillering stage, the lesion-like traits aggravated; heading stage, the lesions in series into pieces, stems, leaves, ears dry and decay. q RT-PCR analysis showed that the expression of Os PR1b, Os NAC4, Os PAL1, Os CHT1, Os CHT3, Os POC1 and other disease-related genes in leaf spot tissue of rcd1 type was significantly higher than that in wild type leaf tissue Level. Field surveys showed that the rcd1 mutant showed increased resistance to the disease. Genetic analysis showed that the rcd1 mutant trait was controlled by a single recessive nuclear gene. The F2 population with 93-11 and rcd1 was used for gene mapping and rcd1 was located in the region of 428 kb between In Del marker ID7909 and ID8337 near chromosome 12 of rice. Sequencing and co-segregation analysis revealed that rcd1 and SL genes were allelic. In the rcd1 mutant, a single-base mutation of G1205T occurs in the coding region of the SL gene, resulting in a variation of the 370th amino acid Arg → Leu. The results of this study may lay a foundation for deeper understanding of rcd1 regulation of rice lesion formation and disease-resistant mechanism.