The mutation of pseudouridine synthase gene BrTRUD1 resulted in glossy leaf in Chinese cabbage

BrTRUD1 encoding pseudouridine synthase was responsible for the glossy leaf in Chinese cabbage, and its function was verified via Arabidopsis transformation. Leaf glossiness is a crucial commercial trait for assessing the market value of Chinese cabbage. We isolated a glossy leaf mutant wdm21 from an EMS-mutagenized population of a DH line 'FT.' Genetic analysis revealed that the mutant trait was controlled by a single recessive nuclear gene. MutMap sequencing and KASP genotyping assays identified BraA03g032280.3.5C as the candidate gene. BraA03g032280.3.5C is an ortholog of Arabidopsis AtTRUD1 encoding pseudouridine synthase. A C-T base substitution occurred at a position 270 bp upstream of the ATG start codon in the BrTRUD1 promoter. This mutation significantly reduced the activity of the promoter and led to lower expression of BrTRUD1 in wdm21. Subcellular localization analysis displayed that BrTRUD1 localized to the nucleus. Heterologous complementation in Arabidopsis demonstrated that trud1 could restore to Col-0 via overexpressing BrTRUD1 in trud1. The research results demonstrated that BrTRUD1 mutant could lead to glossy leaf, which provided Chinese cabbage an excellent commercial trait.