Prioritization of candidate genes regulating the dwarfness in rice by integration of whole-genome and transcriptome analyses

Abstract

Dwarfism is a major trait for developing lodging-resistant rice cultivars. Gamma irradiation-induced mutagenesis has proven to be an effective method for generating dwarf rice mutants. In this research, we isolated a dwarf mutant from Anna R (4) in the M₂ generation and subsequently stabilized the trait through successive selfing of progeny across the M₃-M₇ generations. We then employed whole-genome re-sequencing (WGRS) and RNA sequencing (RNA-seq) analyses of Anna R (4) and the mutant (designated as ACM-20001) to elucidate the underlying mechanisms and identify candidate genes associated with dwarfness. Numerous genetic variations were identified between Anna (R) 4 and ACM-20001 through WGRS. In total, 2049 genetic variants, including 343 InDels and 1706 nonsynonymous SNPs, were identified across 697 genes. Additionally, RNA-seq analysis revealed 2,881 differentially expressed genes between the wild-type Anna (R) 4 and the mutant ACM-20001, with 1,451 genes up-regulated and 1,430 genes down-regulated in ACM-20001 compared to Anna (R) 4. By integrating WGRS and RNA-seq data with functional annotation analysis, we identified the most likely candidate genes (i.e., Os02g0506400, Os05g0515200, Os06g0154200 and Os08g0250900) related to dwarfness. Quantitative real-time PCR analysis verified the expression of these genes. Collectively, our study provides valuable insights in to the genes and mechanisms underlying dwarfness in rice. Further studies are required to elucidate the roles of these candidate genes in dwarfness, which contribute to advancements rice breeding programs.