The New Variation in the Promoter Region of Is Involved in Flowering in .

Flowering time is an important agronomic trait in and has a wide range of variation. The change from vegetative to reproductive development is a major transition period, especially in flowering vegetable crops. In this study, two non-heading Chinese cabbage varieties with significantly different flowering times, Pak-choi ( var. Tesn et Lee) and Caitai ( var. Hort.), were used to construct segregated F populations. The bulk-segregant approach coupled with whole genome re-sequencing was used for QTL sequencing (QTL-seq) analysis to map flowering time traits. The candidate genes controlling flowering time in were predicted by homologous gene alignment and function annotation. The major-effect QTL was detected on chromosome A07 of , and the family gene was predicted as the candidate gene. Moreover, a new promoter regional difference of 1577 bp was revealed by analyzing the sequence of the gene. The promoter region activity analysis and divergent gene expression levels indicated that the difference in the promoter region may contribute to different flowering times. These findings provide insights into the mechanisms underlying the flowering time in and the candidate genes regulating flowering in production.