水稻卷叶突变体基因shallot like1-Fuhui673鉴定、克隆与序列分析

Identification, cloning and sequence analysis of shallot like1-Fuhui673 from a rolled leaf mutant in rice

叶片是水稻进行光合作用的重要器官,其形态直接影响光合作用的强弱.叶片适度卷曲可以使叶片保持直立,改善群体内部透光状况,提高光能利用率,进而提高水稻产量.本研究通过Co60-γ辐照诱变杂交水稻恢复系福恢673,获得一个卷叶突变体,命名为sll1-fh673(shallot-like1 from Fuhui673).经遗传学分析表明,该突变体sll1-fh673卷叶性状受1对隐性基因控制,结合混合群体(BSA)和隐性群体(RCA)分离分析法,将该基因ssl1-fh673精细定位于水稻第9染色体的inD el标记Ri9-20与Ri9-7之间52 kb的区域内.测序结果表明,sll1-fh673(LOC_Os09g23200)的核苷酸序列在第1个外显子第447 bp处由C替换为A,447 bp后缺失5个碱基,导致编码的氨基酸序列从第148位起发生改变并移码,造成蛋白功能异常.因此,推测sll1-fh673是SLL1的新等位基因,该新等位基因的挖掘丰富了SLL1基因的等位资源,有助于深入研究叶片卷曲的形成机理.

Leaves are the important organ for photosynthesis in rice and the strong and weak photosynthesis will be directly influenced with their morphologic structure of leaves. Moderate rolling leaf could keep plants upright, improve light transmittance of population, increase efficiency of light utilization and then increase rice yield. We obtained a rolled leaf mutant, named sll1-fh673（shallot like1-Fuhui673） derived from the restorer line Fuhui673（Oryza sativa L. ssp. indica） of hybrid rice, which were treated with 60 Co-γ radiation. The leaves of the sll1-fh673 rolled inward like a cylinder during the whole growth period. The characteristics of the sll1-fh673 were distinct from those of the wild-type plants, with shorter on plant height and ear length, malformed spikelets, decreased the grain number per spike, smaller grain shape, worse development of the seed. The result of genetic analysis indicated that the phenotype of rolled leaves of sll1-fh673 was controlled by a single recessive nuclear gene. Meanwhile, the sll1-fh673 gene was mapped to a 52-kb region between in Del marker Ri9-20 and Ri9-7 on the Chromosome 9 of rice with Bulked Segregant Analysis and Recessive-class Analysis methods. But there was a cloned rolled leaf gene SLL1（LOC_Os09 g23200） in the mapped regions, which might be the candidate gene of sll1-fh673. The sequencing analysis revealed that there was a single-base substitution from C to A and five-base deletion in the first exon in sll1-fh673 comparing with the SLL1 gene, leading to frame-shift mutation after the 148 aa and dysfunction of sll1 protein. So we speculated that the sll1-fh673 gene might be allelic to SLL1 gene. These results will deepen our understanding the mechanisms of the leaf rolling and enriches the allelic resource of the SLL1 gene. We will predict binding sites of the sll1-fh673 gene and find interacting protein of down-regulation, and then carry out the molecular mechanism of the leaf rolling, such as electrophoretic mobility shift assay（EMSA）, DNA Chip Technology and Yeast One Hybrid System in the future.