Comparative transcriptomics reveals desynchronisation of gene expression during the floral transition between Arabidopsis andBrassica rapacultivars

Comparative transcriptomics can be used to translate an understanding of gene regulatory networks from model systems to less studied species. Here, we use RNA-Seq to determine and compare gene expression dynamics through the floral transition in the model speciesArabidopsis thalianaand the closely related cropBrassica rapa. We find that different curve registration functions are required for different genes, indicating that there is no single common ‘developmental time’ between Arabidopsis andB. rapa. A detailed comparison between Arabidopsis andB. rapaand between twoB. rapaaccessions reveals different modes of regulation of the key floral integratorSOC1, and that the floral transition in theB. rapaaccessions is triggered by different pathways. Our study adds to the mechanistic understanding of the regulatory network of flowering time in rapid cyclingB. rapaand highlights the importance of registration methods for the comparison of developmental gene expression data.