The Evolution of the FT/TFL1 Genes in Amaranthaceae and Their Expression Patterns in the Course of Vegetative Growth and Flowering in Chenopodium rubrum

Abstract

The FT/TFL1 gene family controls important aspects of plant development: MFT-like genes affect germination, TFL1-like genes act as floral inhibitors, and FT-like genes are floral activators. Gene duplications produced paralogs with modified functions required by the specific lifestyles of various angiosperm species. We constructed the transcriptome of the weedy annual plant Chenopodium rubrum and used it for the comprehensive search for the FT/TFL1 genes. We analyzed their phylogenetic relationships across Amaranthaceae and all angiosperms. We discovered a very ancient phylogenetic clade of FT genes represented by the CrFTL3 gene of C. rubrum. Another paralog CrFTL2 showed an unusual structural rearrangement which might have contributed to the functional shift. We examined the transcription patterns of the FT/TFL1 genes during the vegetative growth and floral transition in C. rubrum to get clues about their possible functions. All the genes except for the constitutively expressed CrFTL2 gene, and the CrFTL3 gene, which was transcribed only in seeds, exhibited organ-specific expression influenced by the specific light regime. The CrFTL1 gene was confirmed as a single floral activator from the FT/TFL1 family in C. rubrum. Its floral promoting activity may be counteracted by CrTFL1. C. rubrum emerges as an easily manipulated model for the study of floral induction in weedy fast-cycling plants lacking a juvenile phase.

Evolution and Expression of Reproductive Transition Regulatory Genes FT/TFL1 With Emphasis in Selected Neotropical Orchids

“…However, some MFT genes from few early divergent angiosperms and eudicots form a different group in the absence of A. thaliana homologs. It is likely that these genes belong to yet another subfamily that has been comparatively less sampled (Drabešová et al, 2016). Within the FT/TFL1like clades we were able to identify a number of large scale as well as local duplications and the associated changes in protein sequences in the resulting paralogs.…”

“…The MFT-like copies are not clustered together but rather form the MFT-like grade, which predates the FT/TFL1-like duplication (Supplementary Figure S1). Within this grade MFT1 and MFT2-like groups were labeled (Drabešová et al, 2016). Because of the large number of sequences and the divergence between the FT and the BFT/TFL1like copies, subsequent independent ML analyses for each clade were performed.…”

Phylogenomic Analysis of the PEBP Gene Family from Kalanchoë

“…Furthermore, the BFT-like genes from both species demonstrated novel gene structure with three exons and two introns resulting from a fusion between exon 2 and exon 3 (103 nt). Even though PEBP genes have highly conserved gene structures, some species exhibit novel features such as additional intron/exon in Musa acuminate [3] and Chenopodium rubrum [70], and exon fusion in Zea mays of FT-like genes [24]. KlTFL1.1 was predicted to have alternative transcript as a result of downstream alternative usage of transcription start site (TSS).…”

TheFLOWERING LOCUS T LIKE 2-1gene ofChenopodiumtriggers precocious flowering in Arabidopsis seedlings

“…The orthologs of BvFT2 and BvFT1 were found in all members of the family Amaranthaceae so far analyzed (Drabešová et al ., 2016). The CrFTL1 gene in Oxybasis rubra (syn.…”

“…The FTL2-2 gene underwent dynamic structural evolution. Unlike the FTL2-1 paralog, which contains four conserved exons and three introns similarly to the other angiosperm FT genes, the FTL2-2 acquired an additional exon and intron (Drabešová et al ., 2016). Whereas the complete FTL2-2 gene exists in O. rubra .…”