Comprehensive Effects of Flowering Locus T-Mediated Stem Growth in Tobacco

A gain-of-function mutation at the C-terminus of FT-D1 promotes heading by interacting with 14-3-3A and FDL6 in wheat

Vernalization and photoperiod pathways converging at FT1 control the transition to flowering in wheat. Here, we identified a gain-of-function mutation in FT-D1 that results in earlier heading date (HD), and shorter plant height and spike length in the gamma ray-induced eh1 wheat mutant. Knockout of the wild-type and overexpression of the mutated FT-D1 indicate that both alleles are functional to affect HD and plant height. Protein interaction assays demonstrated that the frameshift mutation in FT-D1eh1 exon 3 led to gain-of-function interactions with 14-3-3A and FDL6, thereby enabling the formation of florigen activation complex (FAC) and consequently activating a flowering-related transcriptomic programme. This mutation did not affect FT-D1eh1 interactions with TaNaKR5 or TaFTIP7, both of which could modulate HD, potentially via mediating FT-D1 translocation to the shoot apical meristem. Furthermore, the 'Segment B' external loop is essential for FT-D1 interaction with FDL6, while residue Y85 is required for interactions with TaNaKR5 and TaFTIP7. Finally, the flowering regulatory hub gene, ELF5, was identified as the FT-D1 regulatory target. This study illustrates FT-D1 function in determining wheat HD with a suite of interaction partners and provides genetic resources for tuning HD in elite wheat lines.

Hormonal Regulation and Stimulation Response of Jatropha curcas L. Homolog Overexpression on Tobacco Leaf Growth by Transcriptome Analysis

The Flowering locus T (FT) gene encodes the florigen protein, which primarily regulates the flowering time in plants. Recent studies have shown that FT genes also significantly affect plant growth and development. The FT gene overexpression in plants promotes flowering and suppresses leaf and stem development. This study aimed to conduct a transcriptome analysis to investigate the multiple effects of Jatropha curcas L. homolog (JcFT) overexpression on leaf growth in tobacco plants. The findings revealed that JcFT overexpression affected various biological processes during leaf development, including plant hormone levels and signal transduction, lipid oxidation metabolism, terpenoid metabolism, and the jasmonic-acid-mediated signaling pathway. These results suggested that the effects of FT overexpression in plants were complex and multifaceted, and the combination of these factors might contribute to a reduction in the leaf size. This study comprehensively analyzed the effects of JcFT on leaf development at the transcriptome level and provided new insights into the function of FT and its homologous genes.

Mechanisms of Vernalization-Induced Flowering in Legumes

Vernalization is the requirement for exposure to low temperatures to trigger flowering. The best knowledge about the mechanisms of vernalization response has been accumulated for Arabidopsis and cereals. In Arabidopsis thaliana, vernalization involves an epigenetic silencing of the MADS-box gene FLOWERING LOCUS C (FLC), which is a flowering repressor. FLC silencing releases the expression of the main flowering inductor FLOWERING LOCUS T (FT), resulting in a floral transition. Remarkably, no FLC homologues have been identified in the vernalization-responsive legumes, and the mechanisms of cold-mediated transition to flowering in these species remain elusive. Nevertheless, legume FT genes have been shown to retain the function of the main vernalization signal integrators. Unlike Arabidopsis, legumes have three subclades of FT genes, which demonstrate distinct patterns of regulation with respect to environmental cues and tissue specificity. This implies complex mechanisms of vernalization signal propagation in the flowering network, that remain largely elusive. Here, for the first time, we summarize the available information on the genetic basis of cold-induced flowering in legumes with a special focus on the role of FT genes.