Abstract
Plant tissue culture is extensively employed in plant functional genomics research and crop genetic improvement breeding. The callus induction ability is critical for utilizing Agrobacterium-mediated genetic transformation. In this study, we conducted a genome-wide association study (GWAS) utilizing 368 rice accessions to identify traits associated with callus induction rate (CIR), resulting in the identification of a total of 104 significant SNP loci. Integrated with gene function annotation and transcriptome analysis, 13 high-confidence candidate genes involved in auxin-related, CYC cyclins, and histone H3K9-specific methyltransferase were identified in significant loci. Furthermore, we also verified a candidate gene, Os05g0493500 (OsCycB1;5), and employed the CRISPR/Cas9 system to generate OsCycB1;5 knockout mutants in rice (Oryza sativa L.). The OscycB1;5 mutant displays significantly reduced callus induction and proliferation capacity, this result indicating OsCycB1;5 is required for the callus formation in rice. Overall, this study provides several reliable loci and high-confidence candidate genes that may significantly affect callus formation in rice. This information will offer valuable insights into the mechanisms underlying callus formation not only in rice but also in other plants.