Molecular genetics and physiological analyses of the transition to flowering in winter rapeseed
Understanding the stages of reproductive development and the genetic factors that control this process is essential to optimize yield and produce varieties that are better adapted to the changing climate. A global gene expression profiling of the SAM, accompanied with detailed histological analyses of the stages of meristematic development of winter rapeseed Express617 during floral transition was performed in this study. The aims were to determine the timing of floral transition and to identify gene paralogs that mark each stage of meristem development. Although some previous studies on rapeseed flowering-time included transcriptome analysis (Jones et al., 2018; O'Neill et al., 2019; Shah et al.,2018), such high resolution of physiological and molecular analysis of the floral transition during the course of vernalization was still lacking. The results of this study provide comprehensive insights of cold-driven floral transition in winter rapeseed, and open new avenues for further flowering time and yield related studies. In this work, we showed through histological analysis, that winter rapeseed plants, at a certain developmental age, initiate floral transition in the first five weeks of vernalization. Through transcriptome analysis, we identified the genes that are associated with different stages of the flowering response, and showed that specific paralogs of Bna.SOC1 (Bna.SOC1.A05 and Bna.SOC1.C04-random) and Bna.SPL5 (Bna.SPL5.C05 and Bna.SPL5.A05) are induced during the early events of the floral transition. Moreover, we investigated the age-dependent responsiveness to vernalization and showed that pre-vernalization growth periods affect the timing of the floral transition in winter rapeseed, and that Bna.SOC1 and Bna.SPL5 genes respond to age-related signals downstream of Bna.FLC. The study on genomic variation in flowering time genes, between spring and winter types, uncovered a novel presence/absence variation upstream of Bna.SOC1.A05 that is associated with growth type in rapeseed.
Use and reproduction:
No license. The provisions of the German Copyright Act (UrhG) apply.
Please note that individual components of the publication may be subject to other licensing or copyright conditions.