Identification of novel candidate gene associated with early heading on chromosome 5B in wheat mutant jg1489.

Heading date (HD) is a critical agronomic trait that influences wheat's adaptation to environmental conditions and plays a pivotal role in yield stability. In this study, an early-heading mutant jg1489 was identified following γ-ray irradiation of the wild type (WT) wheat variety Jing411. This mutant headed 2-3 days earlier than the WT, with no significant differences in other yield-related traits. Bulked Segregant Analysis (BSA), genetic linkage analysis of the F₂ population from a cross between the WT and mutant, and phenotypic validation in F_2:3 lines were used to finely map the HD gene to a 12.4-Mb region on chromosome 5B. Transcriptome analysis of developing spikes from both WT and jg1489 at three key developmental stages revealed that differentially expressed genes (DEGs) were significantly enriched in pathways related to photosynthesis and photosynthesis-antenna proteins, suggesting a potential role in photosynthetic regulation. Within the mapped region, six high-probability candidate genes were identified based on sequence variation and expression patterns. Functional annotation, supported by studies of homologs in other species, highlighted three genes encoding serine proteases, bromodomain-containing protein, and UTP-glucose-1-phosphate uridylyltransferase as the most likely regulators of HD. These findings provide valuable insights into the genetic regulation of HD in wheat and support the development of new wheat varieties with optimized heading times.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01580-2.