- Award ID(s):
- 1905062
- NSF-PAR ID:
- 10211880
- Date Published:
- Journal Name:
- Journal of Experimental Botany
- ISSN:
- 0022-0957
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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We assessed mechanistic temperature influence on flowering by incorporating temperature-responsive flowering mechanisms across developmental age into an existing model. Temperature influences the leaf production rate as well as expression of FLOWERING LOCUS T (FT), a photoperiodic flowering regulator that is expressed in leaves. The Arabidopsis Framework Model incorporated temperature influence on leaf growth but ignored the consequences of leaf growth on and direct temperature influence of FT expression. We measured FT production in differently aged leaves and modified the model, adding mechanistic temperature influence on FT transcription, and causing whole-plant FT to accumulate with leaf growth. Our simulations suggest that in long days, the developmental stage (leaf number) at which the reproductive transition occurs is influenced by day length and temperature through FT, while temperature influences the rate of leaf production and the time (in days) the transition occurs. Further, we demonstrate that FT is mainly produced in the first 10 leaves in the Columbia (Col-0) accession, and that FT accumulation alone cannot explain flowering in conditions in which flowering is delayed. Our simulations supported our hypotheses that: (i) temperature regulation of FT, accumulated with leaf growth, is a component of thermal time, and (ii) incorporating mechanistic temperature regulation of FT can improve model predictions when temperatures change over time.more » « less
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Summary LIKE HETEROCHROMATIN PROTEIN1 (LHP1) encodes the only plant homologue of the metazoan HETEROCHROMATIN PROTEIN1 (HP1) protein family. The LHP1 protein is necessary for proper epigenetic regulation of a range of developmental processes in plants. LHP1 is a transcriptional repressor of flowering‐related genes, such as
FLOWERING LOCUS T (FT ),FLOWERING LOCUS C (FLC ),AGAMOUS (AG ) andAPETALA 3 (AP3 ). We found that LHP1 interacts with importin α‐1 (IMPα‐1), importin α‐2 (IMPα‐2) and importin α‐3 (IMPα‐3) bothin vitro andin vivo . A genetic approach revealed that triple mutation ofimpα‐1 ,impα‐2 andimpα‐3 resulted in Arabidopsis plants with a rapid flowering phenotype similar to that of plants with mutations inlhp1 due to the upregulation ofFT expression. Nuclear targeting of LHP1 was severely impaired in theimpα triple mutant, resulting in the de‐repression of LHP1 target genesAG ,AP3 andSHATTERPROOF 1 as well asFT . Therefore, the importin proteins IMPα‐1, ‐2 and ‐3 are necessary for the nuclear import of LHP1. -
Abstract Background Flowering signals are sensed in plant leaves and transmitted to the shoot apical meristems, where the formation of flowers is initiated. Searches for a diffusible hormone-like signaling entity (“florigen”) went on for many decades, until a product of plant gene
FT was identified as the key component of florigen in the 1990s, based on the analysis of mutants, genetic complementation evidence, and protein and RNA localization studies. Sequence homologs of FT protein are found throughout prokaryotes and eukaryotes; some eukaryotic family members appear to bind phospholipids or interact with the components of the signal transduction cascades. Most FT homologs are known to share a constellation of five charged residues, three of which, i.e., two histidines and an aspartic acid, are located at the rim of a well-defined cavity on the protein surface.Results We studied molecular features of the FT homologs in prokaryotes and analyzed their genome context, to find tentative evidence connecting the bacterial FT homologs with small molecule metabolism, often involving substrates that contain sugar or ribonucleoside moieties. We argue that the unifying feature of this protein family, i.e., a set of charged residues conserved at the sequence and structural levels, is more likely to be an enzymatic active center than a catalytically inert ligand-binding site.
Conclusions We propose that most of FT-related proteins are enzymes operating on small diffusible molecules. Those metabolites may constitute an overlooked essential ingredient of the florigen signal.
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The circadian clock represents a critical regulatory network, which allows plants to anticipate environmental changes as inputs and promote plant survival by regulating various physiological outputs. Here, we examine the function of the clock-regulated transcription factor, CYCLING DOF FACTOR 6 (CDF6), during cold stress in Arabidopsis thaliana . We found that the clock gates CDF6 transcript accumulation in the vasculature during cold stress. CDF6 mis-expression results in an altered flowering phenotype during both ambient and cold stress. A genome-wide transcriptome analysis links CDF6 to genes associated with flowering and seed germination during cold and ambient temperatures, respectively. Analysis of key floral regulators indicates that CDF6 alters flowering during cold stress by repressing photoperiodic flowering components, FLOWERING LOCUS T ( FT ), CONSTANS ( CO ), and BROTHER OF FT (BFT) . Gene ontology enrichment further suggests that CDF6 regulates circadian and developmental-associated genes. These results provide insights into how the clock-controlled CDF6 modulates plant development during moderate cold stress.more » « less
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Abstract Association between seed dormancy (SD) and flowering time (FT) may generate a synergy in plant adaptation. This research aimed to identify patterns and underlying genes of the association in rice (
Oryza sativa ). Four F2and two BC1F1populations from crosses of weedy/cultivated rice, and two families of progeny lines from backcrosses were evaluated for variations in time to flowering and germination ability. The two measurements were correlated negatively in the F2and BC1F1populations, but positively in advanced generations of the progeny lines. The negative correlations were resulted from linkage disequilibria between SD and FT loci at 7–40 cM apart. The positive correlations arose from co-located SD and FT loci undetectable in the BC1F1population. Two independent sets of co-localized loci were isolated as single Mendelian factors, and haplotypes that promote flowering and reduce germination derived from weedy and cultivated rice, respectively. The presence of negative and positive correlations indicates that the rice complex has maintained two contrasting patterns of SD-FT coadaptation, with the positive being “recessive” to the negative pattern. Modeling with isogenic lines suggests that a negative pattern could generate a greater synergy (difference between haplotype variants) than the positive one for seedbank persistence, or enhanced plant adaptation to seasonal changes in temperature or moisture. However, the early-flowering dormant genotype of a positive pattern could also have a selective advantage over its counterpart for weeds to avoid harvesting. The isolated haplotypes could be used to manipulate cultivars simultaneously for germination ability and growth duration.