BraVRG, a novel protein of Brassica rapa, is induced by vernalization and promotes flowering in Arabidopsis thaliana

Abstract

Plant flowering is an important economical characteristic for the transformation from vegetative growth to reproductive growth, especially for biennial crops. Additionally, bolting or flowering time is more important for vegetable plants due to their different harvest organs, such as flower for cauliflower and broccoli and leafy heads for cabbage and Chinese cabbage. The flowering time of Arabidopsis thaliana has six classical regulated pathways, and some key regulated genes are identified in Brassicaceae crops. However, the regulatory mechanism needs further exploration. Here, we reported an novel protein BraVRG (Vernalization Related Gene) of Chinese cabbage induced by vernalization. The expression of BraVRG increased rapidly at 14 day of vernalization in the semi-winter type of Brassica rapa and 21 days for the winter types. Meanwhile the modifications of H3K4me3 deposited on BraVRG increased but H3K27me3 decreased. Moreover, BraVRG promoted flowering in transgenic A. thaliana compared with the wild types accompanied the downregulated expression of FLC caused by the decrease of H3K4me3 enrichment and the increase of H3K27me3 on FLC with or without vernalization conditions.

Keywords: BraVRG; Brassica rapa; Flowering time; Histone modifications.