Work

Functional 5Bq allele is responsible for the compact spike phenotype in common wheat (Triticum aestivum L.)

Year: 2026

Type: article

Abstract: BACKGROUND: Spike morphology is an important characteristic of common wheat because of its effects on yield potential. However, few available genes regulating spike morphology have been reported in common wheat. RESULTS: We identified a compact spike mutant S-Cp2, which was obtained by treating common wheat cultivar ‘Shumai482’ with ethyl methanesulfonate. The gene responsible for the compact spike phenotype of S-Cp2 was mapped and cloned. According to a genetic analysis, the formation of a compact spike in S-Cp2 was controlled by a single dominant locus (Cs-5B) on chromosome 5BL. This locus was mapped to an 87 kb interval between markers KASP-58070 and KASP-58158, wherein 5Bq gene was detected. One missense mutation was called within the microRNA172-binding site of 5Bq in S-Cp2, suggesting that the mutated 5Bq allele (5BQ4) is responsible for the compact spike phenotype. This was confirmed by cloning 5Bq in revertants obtained by treating S-Cp2 with ethyl methanesulfonate. As expected, the 5BQ4 allele was expressed at significantly higher levels than the 5Bq allele in developing spike tissues. According to a haplotype analysis, the functional haplotype 1 for 5Bq was gradually accumulated in modern Chinese wheat cultivars. CONCLUSION: In this study, we identified a functional 5Bq allele by genetic mapping, which was responsible for the compact spike phenotype in mutant S-Cp2. The study findings highlight the potential utility of 5Bq for breeding novel wheat cultivars.

Source: BMC Plant Biology

DOI: 10.1186/s12870-026-08583-x