Current understanding of flowering pathways in plants: focusing on the vernalization pathway in Arabidopsis and several vegetable crop plants

Abstract

Over the decades, extensive studies have been performed to elucidate the molecular mechanisms underlying the floral transition process in model plants, as well as in crop plants. It has been demonstrated that floral integrator genes, such as FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CO 1, are highly conserved in most of the flowering plants. This finding has accelerated the identification and functional analyses of these orthologues involved in floral transition in flowering plant species. Even though the upstream regulator networks of the floral integrator genes seem to be quite diverged among plant species, they share four conserved flowering pathways, including the photoperiod, autonomous, gibberellin, and vernalization pathways. The comprehensive knowledge of the molecular mechanisms underlying floral transitions in the model plant Arabidopsis thaliana has helped us explore and elucidate the molecular mechanisms controlling floral transitions in other crop plants. This review highlights the current understandings of the flowering pathways elucidated in Arabidopsis, and mainly focuses on understanding the vernalization pathway in Arabidopsis as well as in several horticultural crop plants, including those of the genus Brassica.