The FLOWERING LOCUS T (FT) gene is the essential integrator of flowering regulatory pathways in angiosperms. The paralogs of the FT gene may perform antagonistic functions, as exemplified by BvFT1, that suppresses flowering in Beta vulgaris, unlike the paralogous activator BvFT2. The roles of FT genes in other amaranths were less investigated. Here, we transformed Arabidopsis thaliana with the FLOWERING LOCUS T like (FTL) genes of Chenopodium ficifolium and found that both CfFTL1 and CfFTL2-1 accelerated flowering, despite having been the homologs of the Beta vulgaris floral promoter and suppressor, respectively. The floral promotive effect of CfFTL2-1 was so strong that it caused lethality when overexpressed under the 35S promoter. CfFTL2-1 placed in an inducible cassette accelerated flowering after induction with methoxyphenozide. The spontaneous induction of CfFTL2-1 led to precocious flowering in some primary transformants even without chemical induction. The CqFT2-1 homolog from Chenopodium quinoa had the same impact on viability and flowering as CfFTL2-1 when transferred to A. thaliana. After the FTL gene duplication in Amaranthaceae, the FTL1 copy maintained the role of floral activator. The second copy FTL2 underwent subsequent duplication and functional diversification, which enabled it to control the onset of flowering in amaranths to adapt to variable environments.

The FLOWERINGLOCUS T like 2–1 gene of Chenopodium ficifolium andChenopodium quinoa acts as a strong activator of flowering in Arabidopsis, triggering flowering at cotyledon stage and causing lethality when overexpressed.

• Keywords
• Chenopodium, FLOWERING LOCUS T like genes, floral induction, flowering, lethality,
• MeSH
• Arabidopsis * genetics   metabolism   MeSH
• Chenopodium * genetics   metabolism   MeSH
• Flowers genetics   metabolism   MeSH
• Arabidopsis Proteins * genetics   metabolism   MeSH
• Gene Expression Regulation, Plant genetics   MeSH
• Seedlings metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Arabidopsis Proteins * MeSH

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.

• Keywords
• Amaranthaceae, Chenopodium rubrum, FLOWERING LOCUS T/TERMINAL FLOWER1 gene family, evolution, flowering, gene rearrangement, transcriptome,
• MeSH
• Amaranthaceae classification   genetics   growth & development   MeSH
• Phenotype MeSH
• Phylogeny MeSH
• Genetic Variation MeSH
• Genome, Plant MeSH
• Protein Conformation MeSH
• Flowers genetics   MeSH
• Evolution, Molecular * MeSH
• Models, Molecular MeSH
• Multigene Family MeSH
• Organ Specificity MeSH
• Gene Expression Regulation, Plant * MeSH
• Genes, Plant * MeSH
• Plant Proteins chemistry   genetics   MeSH
• Gene Expression Profiling MeSH
• Light MeSH
• Transcriptome MeSH
• Computational Biology methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Plant Proteins MeSH

The proper timing of flowering is essential for the adaptation of plant species to their ever-changing environments. The central position in a complex regulatory network is occupied by the protein FT, which acts as a florigen. We found that light, following a permissive period of darkness, was essential to induce the floral promoter CrFTL1 and to initiate flowering in seedlings of the short-day plant Chenopodium rubrum L. We also identified two novel CONSTANS-like genes in C. rubrum and observed their rhythmic diurnal and circadian expressions. Strong rhythmicity of expression suggested that the two genes might have been involved in the regulation of photoperiod-dependent processes, despite their inability to complement co mutation in A. thaliana. The CrCOL1 and CrCOL2 genes were downregulated by dark-light transition, regardless of the length of a preceding dark period. The same treatment activated the floral promoter CrFTL1. Light therefore affected CrCOL and CrFTL1 in an opposite manner. Both CrCOL genes and CrFTL1 displayed expression patterns unique among short-day plants. Chenopodium rubrum, the subject of classical physiological studies in the past, is emerging as a useful model for the investigation of flowering at the molecular level.

• Keywords
• CONSTANS-like, Chenopodium rubrum, FLOWERING LOCUS T-like, flowering, gene expression, light sensitivity, short-day plant.,
• MeSH
• Arabidopsis MeSH
• Chenopodium genetics   growth & development   physiology   MeSH
• Florigen metabolism   MeSH
• Photoperiod MeSH
• Flowers growth & development   MeSH
• Reverse Transcriptase Polymerase Chain Reaction MeSH
• Promoter Regions, Genetic MeSH
• Gene Expression Regulation, Plant * MeSH
• Plant Proteins genetics   metabolism   MeSH
• Amino Acid Sequence MeSH
• Sequence Alignment MeSH
• Seedlings growth & development   MeSH
• Genetic Complementation Test MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Florigen MeSH
• Plant Proteins MeSH

Chimeric genes are significant sources of evolutionary innovation that are normally created when portions of two or more protein coding regions fuse to form a new open reading frame. In plant mitochondria astonishingly high numbers of different novel chimeric genes have been reported, where they are generated through processes of rearrangement and recombination. Nonetheless, because most studies do not find or report nucleotide variation within the same chimeric gene, evolution after the origination of these chimeric genes remains unstudied. Here we identify two alleles of a complex chimera in Silene vulgaris that are divergent in nucleotide sequence, genomic position relative to other mitochondrial genes, and expression patterns. Structural patterns suggest a history partially influenced by gene conversion between the chimeric gene and functional copies of subunit 1 of the mitochondrial ATP synthase gene (atp1). We identified small repeat structures within the chimeras that are likely recombination sites allowing generation of the chimera. These results establish the potential for chimeric gene divergence in different plant mitochondrial lineages within the same species. This result contrasts with the absence of diversity within mitochondrial chimeras found in crop species.

• MeSH
• Alleles MeSH
• DNA Primers genetics   MeSH
• Species Specificity MeSH
• Phylogeny MeSH
• Transcription, Genetic MeSH
• Genetic Variation MeSH
• Genome, Plant MeSH
• Codon MeSH
• Crosses, Genetic MeSH
• RNA, Messenger metabolism   MeSH
• Genes, Mitochondrial * MeSH
• Models, Genetic MeSH
• Evolution, Molecular MeSH
• Mosaicism MeSH
• Polymerase Chain Reaction MeSH
• Likelihood Functions MeSH
• Arabidopsis Proteins genetics   MeSH
• Proton-Translocating ATPases genetics   MeSH
• Gene Expression Regulation MeSH
• Recombination, Genetic MeSH
• Genes, Plant MeSH
• Silene genetics   MeSH
• Blotting, Southern MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Names of Substances
• ATP1 protein, Arabidopsis MeSH Browser
• DNA Primers MeSH
• Codon MeSH
• RNA, Messenger MeSH
• Arabidopsis Proteins MeSH
• Proton-Translocating ATPases MeSH