水稻类树状突变体pla1-5的鉴定与基因克隆

在粳稻品种台北309经60 Co-γ辐射诱变的后代中发现了一份类树状突变体pla1-5,该突变体表现为植株矮化、叶片小且数量增多、分蘖数减少、高位分蘖、穗分化受阻等特征。遗传分析表明,该性状受一对隐性核基因控制。利用图位克隆技术将目的基因定位在第10染色体长臂上两个分子标记CHR1027和CHR1030之间,物理距离为58kb,并与SSR标记CHR1028和CHR1029共分离。根据水稻基因组序列的注释,该区域内存在5个完整的预测基因。测序分析表明pla1-5突变体中一个编码细胞色素P450CYP78A11的释义基因LOC_Os10g26340第1外显子内缺失了一个碱基T,导致移码突变和翻译提前终止。据此,初步推测细胞色素P450CYP78A11基因为PLA1-5的候选基因。

Identification and Gene Cloning of the Leafy Head Mutant pla1 5 in Rice

From the progeny of a japonica variety Taipei 309 treated with 60Co γ ray irradiation, a leafy head mutant pla1 5 (plasttochron 1 5) with dwarf phenotype and small leaf was identified. Comparing with the wild type, the pla1 5 mutant has more leaves and less tillers, and therefore fails to produce a normal panicle at the maturity stage. The genetic analysis showed that the pla1 5 phenotype was controlled by a single recessive nuclear gene. By the map based cloning, the target gene was finally narrowed down to a 58 kb region between SSR markers CHR1027 and CHR1030 on the long arm of chromosome 10, and co segregates with the molecular markers CHR1028 and CHR1029. There were five predicted genes in the mapped region. The  sequencing analysis results revealed that there was a  deletion of the nucleotide T in the first exon of the gene LOC_Os10g26340 encoding cytochrome P450 CYP78A11 in the pla1 5 mutant, which might result in a downstream frame shift and a premature termination. These results implied that the P450 CYP78A11  gene might be the candidate gene of PLA1 5.