Abstract:
Objective Molecular mechanism of rice senescence was studied by locating and cloning the specific gene from a mutant artificially induced with early senescence.
Methods Japonica rice Yunyin was treated with EMS to artificially induce a genetically stable early senescence w14. The mutant was crossed with Nipponbare to construct an isolated F2 population. Subsequently, equal parts of the DNA of 100 recessive and dominant plants in the population were mixed. The differential loci between these two DNA pools were analyzed by BSA-seq to locate the target early senescence-related gene.
Results The early senescence phenotype of w14 was found to be controlled by a single recessive gene. The mutagenic gene mapped and identified by the specific sequence showed the main peak located in Chr 3 and the candidate interval Chr 3: 27.5–29.5 Mb. In the region, two qualified candidate causal variants were found.
Conclusion The mutation site of the candidate gene Loc_ Os03g49210 located in the 2nd exon was determined to have changed in the wild-type from C to T. It was a non-synonymous mutation that resulted in the 20th amino acid encoded by the gene changed from T (threonine) to I (isoleucine) and led to the functional alternation. Being homologous with human BRCA1, the target gene was named OsBRCA1.
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