Gene mapping and candidate gene analysis of a sorghum sheathed panicle‐I mutant

Abstract

Abstract Panicle exsertion is essential for crop yield and quality, and understanding its molecular mechanisms is crucial for optimizing plant architecture. In this study, the sheathed panicle‐I (shp‐I) mutant was identified from the ethyl methane sulfonate mutant population of the sorghum [Sorghum bicolor (L.) Moench] variety Hongyingzi (HYZ). While phenotypically similar to the wild type during the seedling stage, shp‐I exhibits a significantly shorter peduncle internode at the heading stage. Cytomorphological analysis revealed reduced parenchyma cell size within the mutant's peduncle internode. Phytohormonal profiling showed lower levels of indole‐3‐acetic acid and higher concentrations of brassinosteroid in the mutant compared to the wild type at the peduncle internode. Genetic analysis confirmed that the mutant phenotype was caused by a recessive single‐gene mutation. Through bulked segregant analysis sequencing (BSA‐seq) genetic mapping, the causative locus for the mutant phenotype was localized to a 59.65–59.92 Mb interval on chromosome 10, which contains 28 putative genes. Additionally, the gene SbiHYZ.10G230700, which encodes a BTB/POZ and MATH (BPM) domain protein, was identified as a candidate gene. Further analysis revealed that the non‐synonymous mutations in the candidate gene were located within the MATH domain, affecting the 3D structure of the protein. In summary, this study provides a new genetic material and candidate genes for future research into the molecular regulation of sorghum peduncle length.