Vernalization Regulates Flowering Genes and Modulates Glucosinolates Biosynthesis in Chinese Cabbage

Abstract

Long-term cold exposure, such as that in winter, termed vernalization, provides flowering competence in many winter-annual, biennial, and perennial plants, including Brassicaceae family plants. Vernalization results in significant phenotypic and physiological changes, including floral transition in plants, which are accompanied by transcriptomic changes. To date, studies attempting to determine the molecular processes underpinning vernalization responses, especially flowering, have mainly focused on model Arabidopsis thaliana plants. To better understand the vernalization response in Chinese cabbage (Brassica rapa ssp. pekinensis), we investigated transcriptomic changes occurring during vernalization. We found that thousands of genes were dynamically modulated by both short-term (cold acclimation) and long-term cold (vernalization) exposure, compared with non-vernalized samples. Further, 15 hierarchical clusters of differentially expressed genes were identified based on their distinct expression patterns. A gene ontology analysis using upregulated and downregulated genes during the vernalization time course revealed that metabolic and physiological changes also occur during vernalization. Particularly, we noticed that vernalization upregulated the transcription of glucosinolate (GSL) pathway genes and the levels of corresponding GSL compounds in Chinese cabbage. Overall, vernalization triggers dynamic transcriptomic alterations to not only genes related to floral transition but also genes involved in GSL metabolism in Chinese cabbage plants.