A rare stop-gain SNP mutation in BrGL2 causes aborted trichome development in Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Biyuan Li, Xiaoya Ding, Zhichen Yue, Yanting Zhao, Juanli Lei, Yunxiang Zang, Qizan Hu & Peng Tao

Theoretical and Applied Genetics; May 9 2025; vol.138; article 112

Key message

A rare stop-gain SNP mutation in BrGL2 confers short hair phenotype of Chinese cabbage via bulked-segregant analysis sequencing, fine-mapping and gene silencing analysis.

Abstract

Trichomes negatively affect the quality of Chinese cabbage, a leafy vegetable crop in the family Brassicaceae. The short hair trait is caused by abnormal trichome development. In this study, the BraA07g025490.3C gene was identified as a candidate gene for the short hair trait in Chinese cabbage by BSA-seq and fine-mapping analyses. It was subsequently named BrGL2 because of its strong homology to AtGL2 (At1g79840). Sequence analysis indicated that a C to G single-nucleotide polymorphism (SNP) mutation in the sixth exon of BrGL2 produced a premature stop codon in the HCW (short hair) line, resulting in a loss-of-function mutation of BrGL2. This stop-gain SNP mutation was found exclusively in the HCW line, and not in 524 diverse B. rapa accessions. Further analysis by virus-induced gene silencing showed that the knock-down of BrGL2 in HN19-G lines (wild-type hair) reduced the size of leaf trichomes. BrGL2 affected trichome development probably by impacting the expression of downstream transcription factor genes and cell wall-related genes, as determined by comparative transcriptome analyses of wild type and short hair lines. On the basis of the identification and verification of the key stop-gain SNP mutation in BrGL2 resulting in aborted trichome development in Chinese cabbage, we propose a model for trichome development.

See https://link.springer.com/article/10.1007/s00122-025-04905-z