Premise
The timing and pattern of a plant's flowering can have important consequences for reproductive success. Variation in flowering phenology may influence the number of prospective mates, the ...risk of mating with lower quality individuals, and the likelihood of self‐pollination. Here we use a common garden experiment to explore within‐ and among‐population variation in phenology. Our work provides new insights into how flowering phenology shapes mating opportunity and flowering synchrony in a self‐compatible perennial.
Methods
To quantify variation in flowering phenology we raised progeny from nine populations of Mimulus ringens in a common garden. For each individual, we measured phenological traits including age at flowering onset, daily floral display size, total flower number, and flowering synchrony with other members of the population, and related these traits to mating opportunity. We also tested how individual flowering schedules influence the magnitude of synchrony.
Results
Flowering phenology and synchrony varied substantially within and among populations. From day to day, plants often oscillated between large and small daily floral displays. Additionally, flowering schedules of individual plants strongly influenced flowering synchrony and, along with the number of flowering days, markedly affected plants' mating opportunity.
Conclusions
Phenological traits such as flowering synchrony can affect the quantity of mating opportunities and may be important targets of natural selection. Our results highlight the need for studies that quantify flowering patterns of individuals as well as populations.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Summary
The transition from vegetative to reproductive growth, known as flowering, is a critical developmental process in flowering plants to ensure reproductive success. This process is strictly ...controlled by various internal and external cues; however, the underlying molecular regulatory mechanisms need to be further characterized.
Here, we report a plant‐specific protein, FCS‐LIKE ZINC FINGER PROTEIN 13 (FLZ13), which functions as a hitherto unknown negative modulator of flowering time in Arabidopsis thaliana.
Biochemical analysis showed that FLZ13 directly interacts with FLOWERING LOCUS C (FLC), a major flowering repressor, and that FLZ13 largely depends on FLC to repress the transcription of two core flowering integrators: FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1. In addition, FLZ13 works together with ABSCISIC ACID INSENSITIVE 5 to activate FLC expression to delay flowering.
Taken together, our findings suggest that FLZ13 is an important component of the gene regulatory network for flowering time control in plants.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The timing of the fruit-set stage (i.e., start and end of fruit set) is crucial in a plant's life cycle, but its response to temperature change is still unclear. We investigated the timing of seven ...phenological events, including fruit-set dates during 3 yr for six alpine plants transplanted to warmer (approximately +3.5 °C in soils) and cooler (approximately -3.5 °C in soils) locations along an altitudinal gradient in the Tibetan area. We found that fruit-set dates remained relatively stable under both warming and cooling during the 3-yr transplant experiment. Three earlier phenological events (emergence of first leaf, first bud set, and first flowering) and two later phenological events (first leaf coloring and complete leaf coloring) were earlier by 4.8-8.2 d/°C and later by 3.2-7.1 d/°C in response to warming. Conversely, cooling delayed the three earlier events by 3.8-6.9 d/°C and advanced the two later events by 3.2-8.1 d/°C for all plant species. The timing of the first and/or last fruit-set dates, however, did not change significantly compared to earlier and later phenological events. Statistical analyses also showed that the dates of fruit set were not significantly correlated or had lower correlations with changes of soil temperature relative to the earlier and later phenological events. Alpine plants may thus acclimate to changes in temperature for their fruiting function by maintaining relatively stable timings of fruit set compared with other phenological events to maximize the success of seed maturation and dispersal in response to short-term warming or cooling.
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BFBNIB, FZAB, GIS, IJS, INZLJ, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Synchronised and quasi‐periodic production of seeds by plant populations, known as masting, is implicated in many ecological processes, but how it arises remains poorly understood. Flowering and ...pollination dynamics are hypothesised to provide the mechanistic link for the observed relationship between weather and population‐level seed production. We report the first experimental test of the phenological synchrony hypotheses as a driver of pollen limitation in mast seeding oaks (Quercus ilex). Higher flowering synchrony yielded greater pollination efficiency, which resulted in 2‐fold greater seed set in highly synchronised oaks compared to asynchronous individuals. Pollen addition removed the negative effect of asynchronous flowering on seed set. Because phenological synchrony operates through environmental variation, this result suggests that oak masting is synchronised by exogenous rather than endogenous factors. It also points to a mechanism by which changes in flowering phenology can affect plant reproduction of mast‐seeding plants, with subsequent implications for community dynamics.
Our study demonstrates the causal link between flowering synchrony and seed set in trees. This research provides the first experimental support that pollen limitation due to asynchronous flowering reduces seed set ‐ a key assumption of the phenological synchrony hypothesis. This hypothesis integrates environmental conditions and pollen dynamics, and therefore brings together the two major factors thought to influence interannual synchrony of inter‐annual variation in seed production.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Understanding how flowering phenology responds to warming and cooling (i.e., symmetric or asymmetric response) is needed to predict the response of flowering phenology to future climate change that ...will happen with the occurrence of warm and cold years superimposed upon a long-term trend. A three-year reciprocal translocation experiment was performed along an elevation gradient from 3200 m to 3800 m in the Tibetan Plateau for six alpine plants. Transplanting to lower elevation (warming) advanced the first flowering date (FFD) and transplanting to higher elevation (cooling) had the opposite effect. The FFD of early spring flowering plants (ESF) was four times less sensitive to warming than to cooling (by −2.1 d/°C and 8.4 d/°C, respectively), while midsummer flowering plants (MSF) were about twice as sensitive to warming than to cooling (−8.0 d/°C and 4.9 d/°C, respectively). Compared with pooled warming and cooling data, warming alone significantly underpredicted 3.1 d/°C for ESF and overestimated 1.7 d/°C for MSF. These results suggest that future empirical and experimental studies should consider nonlinear temperature responses that can cause such warming-cooling asymmetries as well as differing life strategies (ESF vs. MSF) among plant species.
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BFBNIB, FZAB, GIS, IJS, INZLJ, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Key message
FKF1 dimerization is crucial for proper
FT
levels to fine-tune flowering time. Attenuating FKF1 homodimerization increased CO abundance by enhancing its COP1 binding, thereby accelerating ...flowering under long days.
In Arabidopsis (
Arabidopsis thaliana
), the blue-light photoreceptor FKF1 (FLAVIN-BINDING, KELCH REPEAT, F-BOX 1) plays a key role in inducing the expression of
FLOWERING LOCUS T
(
FT
), encoding the main florigenic signal in plants, in the late afternoon under long-day conditions (LDs) by forming dimers with
FT
regulators. Although structural studies have unveiled a variant of FKF1 (FKF1 I160R) that disrupts homodimer formation in vitro, the mechanism by which disrupted FKF1 homodimer formation regulates flowering time remains elusive. In this study, we determined that the attenuation of FKF1 homodimer formation enhances
FT
expression in the evening by promoting the increased stability of CONSTANS (CO), a primary activator of
FT
, in the afternoon, thereby contributing to early flowering. In contrast to wild-type FKF1, introducing the FKF1 I160R variant into the
fkf1
mutant led to increased
FT
expression under LDs. In addition, the FKF1 I160R variant exhibited diminished dimerization with FKF1, while its interaction with GIGANTEA (GI), a modulator of FKF1 function, was enhanced under LDs. Furthermore, the FKF1 I160R variant increased the level of CO in the afternoon under LDs by enhancing its binding to COP1, an E3 ubiquitin ligase responsible for CO degradation. These findings suggest that the regulation of FKF1 homodimerization and heterodimerization allows plants to finely adjust
FT
expression levels around dusk by modulating its interactions with GI and COP1.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Agriculture accounts for 70% of the global use of available freshwater. Projections show that demand for water will increase significantly due to climate change, population growth and development of ...agricultural enterprises globally. There is a need to develop water‐use efficient crop cultivars for sustainable agricultural production. Sorghum Sorghum bicolor (L.) Moench. is a powerhouse crop in drier regions supporting more than 500 million people. It is a relatively drought‐tolerant crop adapted to grow and yield in marginal environments where other dominant crops such as maize and wheat fail to survive. However, the mean yield of sorghum in the semi‐arid regions has stagnated around 1.0 ton/ha compared with the global average of 2.5 ton/ha, mainly due to recurrent droughts and heat stress. Breeding for drought‐tolerant cultivars is an economic and sustainable mitigation strategy against the current and projected drought stress. Therefore, the objectives of this review were to document the impact of drought stress and the key mitigation strategies under drought‐prone semi‐arid sorghum production systems. The first section of the review highlighted the impact of drought and its mitigation strategies emphasizing on the use of drought‐tolerant cultivars as the best strategy. This is followed by perspectives on aspects of drought‐response mechanisms, breeding methods and complementary technologies for drought tolerance. Integration of the conventional and molecular breeding technologies with rapid generation advancement methods could reduce the breeding cycle and increase the efficiency of deploying new varieties. Information presented in this review will guide agronomists and breeders to develop and deploy drought‐tolerant sorghum cultivars that are adapted to the changing production environments in the semi‐arid regions.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
In contrast to animals, plants cannot avoid unfavorable temperature conditions. Instead, plants have evolved intricate signaling pathways that enable them to perceive and respond to temperature. ...General acclimation processes that prepare the plant to respond to stressful heat and cold, usually occur throughout the whole plant. More specific temperature responses, however, are limited to certain tissues or cell types. While global responses are amenable to epigenomic analyses, responses which are highly localized are more problematic as the chromatin in question is not easily accessible. Here we review the current knowledge of the epigenetic regulation of FLOWERING LOCUS C and FLOWERING LOCUS T as examples of temperature-responsive flowering time regulators that are expressed broadly throughout the plants and in specific cell types, respectively. While undoubtably extremely successful, we reason that future analyses would benefit from higher spatiotemporal resolution. We conclude by reviewing methods and successful applications of tissue- and cell type-specific epigenomic analyses and provide a brief outlook into the future, single-cell epigenomics.
Floral transition from the vegetative to the reproductive stages is precisely regulated by both environmental and endogenous signals. Among these signals, photoperiod is one of the most important ...environmental factors for onset of flowering. A florigen, FLOWERING LOCUS T ( FT ) in Arabidopsis , has thought to be a major hub in the photoperiod-dependent flowering time regulation. Expression levels of FT likely correlates with potence of flowering. Under long days (LD), FT is mainly synthesized in leaves, and FT protein moves to shoot apical meristem (SAM) where it functions and in turns induces flowering. Recently, it has been reported that Arabidopsis grown under natural LD condition flowers earlier than that grown under laboratory LD condition, in which a red (R)/far-red (FR) ratio of light sources determines FT expression levels. Additionally, FT expression profile changes in response to combinatorial effects of FR light and photoperiod. FT orthologs exist in most of plants and functions are thought to be conserved. Although molecular mechanisms underlying photoperiodic transcriptional regulation of FT orthologs have been studied in several plants, such as rice, however, dynamics in expression profiles of FT orthologs have been less spotlighted. This review aims to revisit previously reported but overlooked expression information of FT orthologs from various plant species and classify these genes depending on the expression profiles. Plants, in general, could be classified into three groups depending on their photoperiodic flowering responses. Thus, we discuss relationship between photoperiodic responsiveness and expression of FT orthologs. Additionally, we also highlight the expression profiles of FT orthologs depending on their activities in flowering. Comparative analyses of diverse plant species will help to gain insight into molecular mechanisms for flowering in nature, and this can be utilized in the future for crop engineering to improve yield by controlling flowering time.
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