A 5‐bp Deletion in BrGL1 Leads to Glabrous Leaves in Chinese Cabbage

ABSTRACT Trichomes are key morphological features that significantly influence the taste and quality of Chinese cabbage ( Brassica rapa ssp. L. pekinensis ), while also enhancing its resistance to biotic and abiotic stresses. In this study, genetic analysis of a segregating F 2 population derived from the trichome leaf Chinese cabbage line ‘12d1’ and the glabrous leaf pakchoi line ‘AB515’ indicated that the glabrous leaf trait is controlled by a single recessive gene. Through bulked segregant analysis (BSA) sequencing, fine mapping, and candidate gene sequence analysis, we identified BrGL1 as the causal gene for trichome formation in Chinese cabbage. Sequence alignment further revealed that a 5‐bp deletion in the third exon of the BrGL1 gene in ‘AB515’ resulted in a premature termination of BrGL1. Transcriptome profiling further demonstrates impaired trichome development in ‘AB515’. BrGL1 was localized to the nucleus and exhibited self‐activation activity. Yeast one hybrid and dual‐luciferase assays indicated that BrGL1 directly binds to the BrTTG2 promoter and activates its expression. These findings provide valuable resources for elucidating the molecular mechanism of leaf trichome formation in Chinese cabbage and for genetic improvement.