1. Comparing the regulation and function of FLOWERING LOCUS T homologues in Brassica napus
- Author
-
Wang, Juanjuan and Wang, Juanjuan
- Abstract
Brassica napus, a crop that greatly contributes to global agricultural economies, originated approximately 7,500 years ago through interspecific hybridization between Brassica rapa and Brassica oleracea, resulting in a complex genome with A and C sub-genomes. Flowering time is a crucial phenological trait that directly affects the yield potential and economic sustainability of B. napus. In Arabidopsis thaliana, the FLOWERING LOCUS T (FT) gene plays a pivotal role in flowering regulation. It encodes florigen, a mobile signal that is synthesized in leaves and moves to the apical meristem to trigger the transition from vegetative to reproductive growth. Despite the well-characterized functions and regulatory mechanisms of FT in A. thaliana, knowledge about the FT homologues in B. napus, a species belonging to the same family as A. thaliana, is relatively limited. To address this, we identified and characterized eight FT homologues in B. napus. Among these genes, four BnFT genes show synteny among A. thaliana, Schrenkiella parvula and B. napus, two out of the three NEW SISTER OF FT AND TSF (NFT) genes that possess synteny only among the B. napus and S. parvula were predicted to be pseudogenes, and a C-GENOME SISTER OF FT AND TSF (CFT) gene is unique to B. napus and the C-genome parent, B. oleracea, but absent from S. parvula and A. thaliana. In inter-species complementation experiments, six functional FT homologues all exhibited weaker complementation ability compared to FT, but when expressed directly in the shoot apical meristem, four BnFTs exhibited a similar and strong florigen function as FT, whereas BnNFT.A7 and BnCFT.C4 still showed reduced florigen activity. Furthermore, four BnFT genes contain conserved sequence Block A, Block C and Block E in their flanking sequences, which are known to be involved in the transcriptional regulation of FT. The four BnFT genes are expressed predominantly in long-day conditions, showing an upward parabola of diurnal expression wi
- Published
- 2024