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This article examines the role of FIO1, an RNA methyltransferase, in alternative splicing and its impact on flowering regulation in Arabidopsis thaliana. The authors analyze previous studies and find that differences in conclusions may be due to variations in experimental conditions and data analysis methods. They also compare different tools for detecting differential splicing and find that exon-based tools have higher recall rates, while event-based tools have higher precision rates. The study provides insights into the molecular functions of FIO1 and emphasizes the importance of considering experimental conditions and data analysis in research. Additionally, the article explores the potential influence of FIO1 on flowering time but acknowledges the need for further research to fully understand its mechanisms and environmental adaptation. [Extracted from the article]

Summary: Flowering is a vital agronomic trait that determines the economic value of most ornamental plants. The flowering time of rose (Rosa spp.) is photoperiod insensitive and is thought to be tightly controlled by light intensity, although the detailed molecular mechanism remains unclear.Here, we showed that rose plants flower later under low‐light (LL) intensity than under high‐light (HL) intensity, which is mainly related to the stability of PHYTOCHROME‐INTERACTING FACTORs (RcPIFs) mediated by OPEN STOMATA 1‐Like (RcOST1L) under different light intensity regimes.We determined that HL conditions trigger the rapid phosphorylation of RcPIFs before their degradation. A yeast two‐hybrid screen identified the kinase RcOST1L as interacting with RcPIF4. Moreover, RcOST1L positively regulated rose flowering and directly phosphorylated RcPIF4 on serine 198 to promote its degradation under HL conditions. Additionally, phytochrome B (RcphyB) enhanced RcOST1L‐mediated phosphorylation of RcPIF4 via interacting with the active phyB‐binding motif. RcphyB was activated upon HL and recruited RcOST1L to facilitate its nuclear accumulation, in turn leading to decreased stability of RcPIF4 and flowering acceleration.Our findings illustrate how RcPIF abundance safeguards proper rose flowering under different light intensities, thus uncovering the essential role of RcOST1L in the RcphyB–RcPIF4 module in flowering. [ABSTRACT FROM AUTHOR]

Plant architecture is central in determining crop yield. In the short-day species strawberry, a crop vegetatively propagated by daughter-plants produced by stolons, fruit yield is further dependent on the trade-off between sexual reproduction (fruits) and asexual reproduction (daughter-plants). Both are largely dependent on meristem identity, which establishes the development of branches, stolons and inflorescences. Floral initiation and plant architecture are modulated by the balance between two related proteins, FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1). We explored in woodland strawberry the role of the uncharacterised FveFT2 and FveFT3 genes and of the floral repressor FveTFL1 through gene expression analyses, grafting and genetic transformation (overexpression and gene editing). We demonstrate the unusual properties of these genes. FveFT2 is a nonphotoperiodic florigen permitting short-day (SD) flowering and FveTFL1 is the long-hypothesised long-day systemic antiflorigen that contributes, together with FveFT2, to the photoperiodic regulation of flowering. We additionally show that FveFT3 is not a florigen but promotes plant branching when overexpressed, that is likely to be through changing axillary meristem fate, therefore resulting in a 3.5-fold increase in fruit yield at the expense of stolons. We show that our findings can be translated into improvement of cultivated strawberry in which FveFT2 overexpression significantly accelerates flowering.

Summary: Urbanization can affect the timing of plant reproduction (i.e. flowering and fruiting) and associated ecosystem processes. However, our knowledge of how plant phenology responds to urbanization and its associated environmental changes is limited.Herbaria represent an important, but underutilized source of data for investigating this question. We harnessed phenological data from herbarium specimens representing 200 plant species collected across 120 yr from the eastern US to investigate the spatiotemporal effects of urbanization on flowering and fruiting phenology and frost risk (i.e. time between the last frost date and flowering).Effects of urbanization on plant reproductive phenology varied significantly in direction and magnitude across species ranges. Increased urbanization led to earlier flowering in colder and wetter regions and delayed fruiting in regions with wetter spring conditions. Frost risk was elevated with increased urbanization in regions with colder and wetter spring conditions.Our study demonstrates that predictions of phenological change and its associated impacts must account for both climatic and human effects, which are context dependent and do not necessarily coincide. We must move beyond phenological models that only incorporate temperature variables and consider multiple environmental factors and their interactions when estimating plant phenology, especially at larger spatial and taxonomic scales. See also the Commentary on this article by Zhu & Song, 239: 2057–2059. [ABSTRACT FROM AUTHOR]

We then modeled the residuals of these models against: (a) temperature; (b) temperature and its quadratic; (c) temperature and its cubic; and (d) temperature as a saturating exponential decay. The extremity of recent phenology is stark: during this 10 SP th sp decade of study, the record for the highest average annual temperature was broken six times and, in 2021 alone, species at nine of the 72 sites exhibited the earliest flowering phenology ever recorded. Keywords: climate change; flowering; Korea Meteorological Agency; phenological variance; woody plant phenology EN climate change flowering Korea Meteorological Agency phenological variance woody plant phenology 824 829 6 07/03/23 20230801 NES 230801 Data availability All reproducible analysis codes are released in the Supporting Information; the data are housed with the Korean Meteorological Agency and are also released in the Supporting Information. Climate change, flowering, phenological variance, Korea Meteorological Agency, woody plant phenology. [Extracted from the article]

Summary: The histone variant H2A.Z plays key functions in transcription and genome stability in all eukaryotes ranging from yeast to human, but the molecular mechanisms by which H2A.Z is incorporated into chromatin remain largely obscure.Here, we characterized the two homologs of yeast Chaperone for H2A.Z‐H2B (Chz1) in Arabidopsis thaliana, AtChz1A and AtChz1B. AtChz1A/AtChz1B were verified to bind to H2A.Z‐H2B and facilitate nucleosome assembly in vitro. Simultaneous knockdown of AtChz1A and AtChz1B, which exhibit redundant functions, led to a genome‐wide reduction in H2A.Z and phenotypes similar to those of the H2A.Z‐deficient mutant hta9‐1hta11‐2, including early flowering and abnormal flower morphologies.Interestingly, AtChz1A was found to physically interact with ACTIN‐RELATED PROTEIN 6 (ARP6), an evolutionarily conserved subunit of the SWR1 chromatin‐remodeling complex. Genetic interaction analyses showed that atchz1a‐1atchz1b‐1 was hypostatic to arp6‐1. Consistently, genome‐wide profiling analyses revealed partially overlapping genes and fewer misregulated genes and H2A.Z‐reduced chromatin regions in atchz1a‐1atchz1b‐1 compared with arp6‐1.Together, our results demonstrate that AtChz1A and AtChz1B act as histone chaperones to assist the deposition of H2A.Z into chromatin via interacting with SWR1, thereby playing critical roles in the transcription of genes involved in flowering and many other processes. [ABSTRACT FROM AUTHOR]

Summary: Alternative splicing of pre‐mRNAs is crucial for plant growth and development. Serine/arginine‐rich (SR) proteins are a conserved family of RNA‐binding proteins that are critical for both constitutive and alternative splicing. However, how phosphorylation of SR proteins regulates gene transcription and alternative splicing during plant development is poorly understood.We found that the Arabidopsis thaliana L. SR protein‐specific kinase II family proteins (SRPKIIs) play an important role in plant development, including flowering. SRPKIIs regulate the phosphorylation status of a subset of specific SR proteins, including SR45 and SC35, which subsequently mediates their subcellular localization.A phospho‐dead SR45 mutant inhibits the assembly of the apoptosis‐and splicing‐associated protein complex and thereby upregulates the expression of FLOWERING LOCUS C (FLC) via epigenetic modification. The splicing efficiency of FLC introns was significantly increased in the shoot apex of the srpkii mutant. Transcriptomic analysis revealed that SRPKIIs regulate the alternative splicing of c. 400 genes, which largely overlap with those regulated by SR45 and SC35‐SCL family proteins.In summary, we found that Arabidopsis SRPKIIs specifically affect the phosphorylation status of a subset SR proteins and regulate the expression and alternative splicing of FLC to control flowering time. [ABSTRACT FROM AUTHOR]

Summary: Chromatin is a dynamic platform within which gene expression is controlled by epigenetic modifications, notably targeting amino acid residues of histone H3. Among them is lysine 27 of H3 (H3K27), the trimethylation of which by the Polycomb Repressive Complex 2 (PRC2) is instrumental in regulating spatiotemporal patterns of key developmental genes. H3K27 is also subjected to acetylation and is found at sites of active transcription. Most information on the function of histone residues and their associated modifications in plants was obtained from studies of loss‐of‐function mutants for the complexes that modify them.To decrypt the genuine function of H3K27, we expressed a non‐modifiable variant of H3 at residue K27 (H3.3K27A) in Arabidopsis, and developed a multi‐scale approach combining in‐depth phenotypical and cytological analyses, with transcriptomics and metabolomics.We uncovered that the H3.3K27A variant causes severe developmental defects, part of them are reminiscent of PRC2 mutants, part of them are new. They include early flowering, increased callus formation and short stems with thicker xylem cell layer. This latest phenotype correlates with mis‐regulation of phenylpropanoid biosynthesis.Overall, our results reveal novel roles of H3K27 in plant cell fates and metabolic pathways, and highlight an epigenetic control point for elongation and lignin composition of the stem. [ABSTRACT FROM AUTHOR]

Dr. Steven H. Strauss, a University Distinguished Professor of Forest Biotechnology at Oregon State University, discusses his interest in plant science and his motivation to pursue a career in research. He credits his mentors during his PhD at the University of California at Berkeley for being his role models. Dr. Strauss highlights some of his favorite papers from the New Phytologist journal, including one on the genetic variation in amenability to genetic transformation and regeneration, another on the determination of crown phenology in quaking aspen, and a third on lignin modification in poplar. He also expresses his fondness for poplars, especially aspens and cottonwoods, due to their beauty and amenability to biotech methods. [Extracted from the article]

Summary: Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone‐setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone‐like structures, called transition shoots, in positions where wild‐type P. abies always produces vegetative shoots.We collect acrocona and wild‐type samples, and RNA‐sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele‐specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees.A member of the SQUAMOSA BINDING PROTEIN‐LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co‐segregation between the early cone‐setting phenotype and trees homozygous for the acrocona mutation.In conclusion, we demonstrate evolutionary conservation of the age‐dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies. [ABSTRACT FROM AUTHOR]

Summary: Arabis alpina is a polycarpic perennial, in which PERPETUAL FLOWERING1 (PEP1) regulates flowering and perennial traits in a vernalization‐dependent manner. Mutagenesis screens of the pep1 mutant established the role of other flowering time regulators in PEP1‐parallel pathways.Here we characterized three allelic enhancers of pep1 (eop002, 085 and 091) which flower early. We mapped the causal mutations and complemented mutants with the identified gene. Using quantitative reverse transcriptase PCR and reporter lines, we determined the protein spatiotemporal expression patterns and localization within the cell. We also characterized its role in Arabidopsis thaliana using CRISPR and in A. alpina by introgressing mutant alleles into a wild‐type background.These mutants carried lesions in an AAA+ ATPase of unknown function, FLOWERING REPRESSOR AAA+ATPase 1 (AaFRAT1). AaFRAT1 was detected in the vasculature of young leaf primordia and the rib zone of flowering shoot apical meristems. At the subcellular level, AaFRAT1 was localized at the interphase between the endoplasmic reticulum and peroxisomes. Introgression lines carrying Aafrat1 alleles required less vernalization to flower and reduced number of vegetative axillary branches. By contrast, A. thaliana CRISPR lines showed weak flowering phenotypes.AaFRAT1 contributes to flowering time regulation and the perennial growth habit of A. alpina. [ABSTRACT FROM AUTHOR]

Summary: Plant–pollinator mutualisms rely upon the synchrony of interacting taxa. Climate change can disrupt this synchrony as phenological responses to climate vary within and across species. However, intra‐ and interspecific variation in phenological responses is seldom considered simultaneously, limiting our understanding of climate change impacts on interactions among taxa across their ranges.We investigated how variation in phenological sensitivity to climate can alter ecological interactions simultaneously within and among species using natural history collections and citizen science data. We focus on a unique system, comprising a wide‐ranged spring ephemeral with varying color morphs (Claytonia virginica) and its specialist bee pollinator (Andrena erigeniae).We found strongly opposing trends in the phenological sensitivities of plants vs their pollinators. Flowering phenology was more sensitive to temperature in warmer regions, whereas bee phenology was more responsive in colder regions. Phenological sensitivity varied across flower color morphs. Temporal synchrony between flowering and pollinator activity was predicted to change heterogeneously across the species' ranges in the future.Our work demonstrates the complexity and fragility of ecological interactions in time and the necessity of incorporating variation in phenological responses across multiple axes to understand how such interactions will change in the future. [ABSTRACT FROM AUTHOR]

Summary: Plants age by developmental phase changes. In Arabidopsis, the juvenile to adult vegetative phase change (VPC) is marked by clear heteroblastic changes in leaves. VPC and the subsequent vegetative to reproductive phase change are promoted by SQUAMOSA PROMOTOR BINDING PROTEIN‐LIKE (SPL) transcription factors and repressed by miR156/157 targeting SPL transcripts.By genetic, phenotypic, and gene expression analyses, we studied the role of the longevity‐promoting AT‐HOOK MOTIF NUCLEAR LOCALIZED 15 (AHL15) and family members in SPL‐driven plant ageing.Arabidopsis ahl loss‐of‐function mutants showed accelerated VPC and flowering, whereas AHL15 overexpression delayed these phase changes. Expression analysis and tissue‐specific AHL15 overexpression revealed that AHL15 affects VPC and flowering time directly through its expression in the shoot apical meristem and young leaves, and that AHL15 represses SPL2/9/13/15 gene expression in a miR156/157‐independent manner. The juvenile traits of spl loss‐of‐function mutants appeared to depend on enhanced expression of the AHL15 gene, whereas SPL activity prevented vegetative growth from axillary meristem by repressing AHL15 expression.Our results place AHL15 and close family members together with SPLs in a reciprocal regulatory feedback loop that modulates VPC, flowering time, and axillary meristem development in response to both internal and external signals. [ABSTRACT FROM AUTHOR]

Summary: Today plants often flower earlier due to climate warming. Herbarium specimens are excellent witnesses of such long‐term changes. However, the magnitude of phenological shifts may vary geographically, and the data are often clustered. Therefore, large‐scale analyses of herbarium data are prone to pseudoreplication and geographical biases.We studied over 6000 herbarium specimens of 20 spring‐flowering forest understory herbs from Europe to understand how their phenology had changed during the last century. We estimated phenology trends with or without taking spatial autocorrelation into account.On average plants now flowered over 6 d earlier than at the beginning of the last century. These changes were strongly associated with warmer spring temperatures. Flowering time advanced 3.6 d per 1°C warming. Spatial modelling showed that, in some parts of Europe, plants flowered earlier or later than expected. Without accounting for this, the estimates of phenological shifts were biased and model fits were poor.Our study indicates that forest wildflowers in Europe strongly advanced their phenology in response to climate change. However, these phenological shifts differ geographically. This shows that it is crucial to combine the analysis of herbarium data with spatial modelling when testing for long‐term phenology trends across large spatial scales. [ABSTRACT FROM AUTHOR]

Summary: The APETALA2 (AP2) transcription factor regulates flower development, floral transition and shoot apical meristem (SAM) maintenance in Arabidopsis. AP2 is also regulated at the post‐transcriptional level by microRNA172 (miR172), but the contribution of this to SAM maintenance is poorly understood.We generated transgenic plants carrying a form of AP2 that is resistant to miR172 (rAP2) or carrying a wild‐type AP2 susceptible to miR172. Phenotypic and genetic analyses were performed on these lines and mir172 mutants to study the role of AP2 regulation by miR172 on meristem size and the rate of flower production.We found that rAP2 enlarges the inflorescence meristem by increasing cell size and cell number. Misexpression of rAP2 from heterologous promoters showed that AP2 acts in the central zone (CZ) and organizing center (OC) to increase SAM size. Furthermore, we found that AP2 is negatively regulated by AUXIN RESPONSE FACTOR 3 (ARF3). However, genetic analyses indicated that ARF3 also influences SAM size and flower production rate independently of AP2.The study identifies miR172/AP2 as a regulatory module controlling inflorescence meristem size and suggests that transcriptional regulation of AP2 by ARF3 fine‐tunes SAM size determination. [ABSTRACT FROM AUTHOR]

Summary: Plants have evolved to time their leafing, flowering and fruiting in appropriate seasons for growth, reproduction and resting. As a consequence of their adaptation to geographically different environments, there is a rich diversity in plant phenology from temperate and tropical climates. Recent progress in genetic and molecular studies will provide numerous opportunities to study the genetic basis of phenological traits and the history of adaptation of phenological traits to seasonal and aseasonal environments. Integrating molecular data with long‐term phenology and climate data into predictive models will be a powerful tool to forecast future phenological changes in the face of global environmental change. Here, we review the cross‐scale approach from genes to plant communities from three aspects: the latitudinal gradient of plant phenology at the community level, the environmental and genetic factors underlying the diversity of plant phenology, and an integrated approach to forecast future plant phenology based on genetically informed knowledge. Synthesizing the latest knowledge about plant phenology from molecular, ecological and mathematical perspectives will help us understand how natural selection can lead to the further evolution of the gene regulatory mechanisms in phenological traits in future forest ecosystems. [ABSTRACT FROM AUTHOR]

Summary: Many woody plants produce large floral displays early in the spring when xylem transport can be variable and often reduced. To determine whether stem hydraulics impact floral water use, we quantified floral transpiration and tested whether it was correlated with stem xylem conductivity in five temperate woody species that flower before producing leaves.We measured inflorescence gas exchange, examined the relationship between diffusive conductance and inflorescence morphology, and estimated the amount of water supplied to an inflorescence by the phloem. We also tested for correlation between transpiration and native stem xylem conductivity for branches with leaves and branches with flowers.The flowers of our study species obtain most of their water from the xylem. Diffusive conductance was higher in small inflorescences, but water content and daily transpiration rates were greater for larger inflorescences. We found no correlation between floral transpiration per branch and stem xylem conductivity within species.The data suggest that inflorescence water loss during anthesis is not limited by the xylem in our study species. We highlight the impact of floral morphology on hydraulic traits and encourage exploration into temporal shifts in floral hydration. [ABSTRACT FROM AUTHOR]

Summary: In Citrus, the response to environmental floral inductive signals is inhibited by the presence of developing fruits. The mechanism involves epigenetic activation of the CcMADS19 locus (FLC orthologue), encoding a floral repressor.To understand how this epigenetic regulation is reverted to allow flowering in the following season, we have forced precocious sprouting of axillary buds in fruit‐bearing shoots, and examined the competence to floral inductive signals of old and new leaves derived from them.We have found that CcMADS19 is enriched in repressive H3K27me3 marks in young, but not old leaves, revealing that axillary buds retain a silenced version of the floral repressor that is mitotically transmitted to the newly emerging leaves, which are able to induce flowering.Therefore, we propose that flowering in Citrus is necessarily preceded by vegetative sprouting, so that the competence to respond to floral inductive signals is reset in the new leaves. [ABSTRACT FROM AUTHOR]

Summary: Evolutionarily conserved DEK domain‐containing proteins have been implicated in multiple chromatin‐related processes, mRNA splicing and transcriptional regulation in eukaryotes.Here, we show that two DEK proteins, DEK3 and DEK4, control the floral transition in Arabidopsis. DEK3 and DEK4 directly associate with chromatin of related flowering repressors, FLOWERING LOCUS C (FLC), and its two homologs, MADS AFFECTING FLOWERING4 (MAF4) and MAF5, to promote their expression.The binding of DEK3 and DEK4 to a histone octamer in vivo affects histone modifications at FLC, MAF4 and MAF5 loci. In addition, DEK3 and DEK4 interact with RNA polymerase II and promote the association of RNA polymerase II with FLC, MAF4 and MAF5 chromatin to promote their expression.Our results show that DEK3 and DEK4 directly interact with chromatin to facilitate the transcription of key flowering repressors and thus prevent precocious flowering in Arabidopsis. [ABSTRACT FROM AUTHOR]

Summary: Rice is a facultative short day (SD) plant. In addition to serving as a model plant for molecular genetic studies of monocots, rice is a staple crop for about half of the world's population. Heading date is a critical agronomic trait, and many genes controlling heading date have been cloned over the last 2 decades. The mechanism of flowering in rice from recognition of day length by leaves to floral activation in the shoot apical meristem has been extensively studied. In this review, we summarise current progress on transcriptional and post‐transcriptional regulation of heading date in rice, with emphasis on post‐translational modifications of key regulators, including Heading date 1 (Hd1), Early heading date 1 (Ehd1), Grain number, plant height, and heading date7 (Ghd7). The contribution of heading date genes to heterosis and the expansion of rice cultivation areas from low‐latitude to high‐latitude regions are also discussed. To overcome the limitations of diverse genetic backgrounds used in heading date studies and to gain a clearer understanding of flowering in rice, we propose a systematic collection of genetic resources in a common genetic background. Strategies in breeding adapted cultivars by rational design are also discussed. [ABSTRACT FROM AUTHOR]

Summary: Flowering is regulated by genes that respond to changing daylengths and temperature, which have been well studied using controlled conditions; however, the molecular processes underpinning flowering in nature remain poorly understood.Here, we investigate the genetic pathways that coordinate flowering and inflorescence development of wheat (Triticum aestivum) as daylengths extend naturally in the field, using lines that contain variant alleles for the key photoperiod gene, Photoperiod‐1 (Ppd‐1).We found flowering involves a stepwise increase in the expression of FLOWERING LOCUS T1 (FT1), which initiates under day‐neutral conditions of early spring. The incremental rise in FT1 expression is overridden in plants that contain a photoperiod‐insensitive allele of Ppd‐1, which hastens the completion of spikelet development and accelerates flowering time. The accelerated inflorescence development of photoperiod‐insensitive lines is promoted by advanced seasonal expression of floral meristem identity genes. The completion of spikelet formation is promoted by FLOWERING LOCUS T2, which regulates spikelet number and is activated by Ppd‐1.In wheat, flowering under natural photoperiods is regulated by stepwise increases in the expression of FT1, which responds dynamically to extending daylengths to promote early inflorescence development. This research provides a strong foundation to improve yield potential by fine‐tuning the photoperiod‐dependent control of inflorescence development. [ABSTRACT FROM AUTHOR]

Summary: Climate warming may stimulate growth and reproduction in cold‐adapted plants, but also reduce their performance due to warming‐induced drought limitation. We tested this theory using a unique experiment with the alpine forb Rumex alpinus.We examined how climate warming over the past four decades affected its annual rhizome growth, leaf production and flowering, and whether responses varied between alpine, subalpine and montane populations.Before the period of accelerated warming in the 1970s and 1980s, the primary limitation on growth had been cold temperatures and short growing seasons. Increased summer temperatures in the 1990s and 2000s enhanced rhizome growth and leaf production, but not flowering. Alpine and subalpine plants profit more than montane plants, currently producing three times longer annual rhizome increments and twice as many leaves as 40 yr ago, and achieving nearly the same values as montane plants. During the warmest 2005–2015 period, growth became contingent on summer precipitation and began to decrease across all populations, likely due to an increasing water shortage in dense monospecific stands. Warming releases plants from cold limitations but induces water shortage.Rumex alpinus exceeds its thermal optimum and becomes water‐limited as the climate warms. Our results suggest that warming‐induced responses in alpine plants will not be one‐sided shifts to higher growth and reproduction, but rather multidimensional and spatiotemporally variable. [ABSTRACT FROM AUTHOR]

Summary: The timing of reproduction is a critical developmental decision in the life cycle of many plant species.Fine mapping of a rapid‐flowering mutant was done using whole‐genome sequence data from bulked DNA from a segregating F2 mapping populations. The causative mutation maps to a gene orthologous with the third subunit of DNA polymerase δ (POLD3), a previously uncharacterized gene in plants. Expression analyses of POLD3 were conducted via real time qPCR to determine when and in what tissues the gene is expressed.To better understand the molecular basis of the rapid‐flowering phenotype, transcriptomic analyses were conducted in the mutant vs wild‐type. Consistent with the rapid‐flowering mutant phenotype, a range of genes involved in floral induction and flower development are upregulated in the mutant.Our results provide the first characterization of the developmental and gene expression phenotypes that result from a lesion in POLD3 in plants. See also the Commentary on this article by Catalán & Vogel, 227: 1587–1590. [ABSTRACT FROM AUTHOR]

Summary: Perennials have a complex shoot architecture with axillary meristems organized in zones of differential bud activity and fate. This includes zones of buds maintained dormant for multiple seasons and used as reservoirs for potential growth in case of damage. The shoot of Arabis alpina, a perennial relative of Arabidopsis thaliana, consists of a zone of dormant buds placed between subapical vegetative and basal flowering branches. This shoot architecture is shaped after exposure to prolonged cold, required for flowering.To understand how vernalization ensures the maintenance of dormant buds, we performed physiological and transcriptome studies, followed the spatiotemporal changes of auxin, and generated transgenic plants.Our results demonstrate that the complex shoot architecture in A. alpina is shaped by its flowering behavior, specifically the initiation of inflorescences during cold treatment and rapid flowering after subsequent exposure to growth‐promoting conditions. Dormant buds are already formed before cold treatment. However, dormancy in these buds is enhanced during, and stably maintained after, vernalization by a BRC1‐dependent mechanism. Post‐vernalization, stable maintenance of dormant buds is correlated with increased auxin response, transport, and endogenous indole‐3‐acetic acid levels in the stem.Here, we provide a functional link between flowering and the maintenance of dormant buds in perennials. [ABSTRACT FROM AUTHOR]

Summary: Phenology, the study of seasonal timing of events in nature, plays a key role in the matching between organisms and their environment. Yet, it has been poorly integrated in trait‐based descriptions of the plant phenotype. Here, we focus on three phases of reproductive phenology – time of flowering, time of seed dispersal and duration of seed maturation – to test how these traits relate to other recognized dimensions of plant functioning.Traits describing reproductive phenology, together with reproductive plant height, seed mass, area of a leaf, and traits involved in leaf economics, were compiled for 139 species growing under Mediterranean climate conditions.Across all species, flowering time was positively related to reproductive height, while the duration of seed maturation was related to leaf economics. Relationships differed among growth forms, however: flowering time and reproductive height were related both in annuals and in herbaceous perennials, whereas the duration of seed maturation was related to seed mass only in annuals; no correlations were found for woody species.Phenology relates to other dimensions of plant functioning in a complex manner, suggesting that it should be considered as an independent dimension in the context of plant strategies. [ABSTRACT FROM AUTHOR]

Summary: In many perennial plants, seasonal flowering is primarily controlled by environmental conditions, but in certain polycarpic plants, environmental signals are locally gated by the presence of developing fruits initiated in the previous season through an unknown mechanism.Polycarpy is defined as the ability of plants to undergo several rounds of reproduction during their lifetime, alternating vegetative and reproductive meristems in the same individual.To understand how fruits regulate flowering in polycarpic plants, we focused on alternate bearing in Citrus trees that had been experimentally established as fully flowering or nonflowering.We found that the presence of the fruit causes epigenetic changes correlating with the induction of the CcMADS19 floral repressor, which prevents the activation of the floral promoter CiFT2 even in the presence of the floral inductive signals. By contrast, newly emerging shoots display an opposite epigenetic scenario associated with CcMADS19 repression, thereby allowing the activation of CiFT2 the following cold season. See also the Commentary on this article by Hoijemberg & Cerdán, 225: 10–12. [ABSTRACT FROM AUTHOR]

Summary: Pleiotropy occurs when one gene influences more than one trait, contributing to genetic correlations among traits. Consequently, it is considered a constraint on the evolution of adaptive phenotypes because of potential antagonistic selection on correlated traits, or, alternatively, preservation of functional trait combinations. Such evolutionary constraints may be mitigated by the evolution of different functions of pleiotropic genes in their regulation of different traits. Arabidopsis thaliana flowering‐time genes, and the pathways in which they operate, are among the most thoroughly studied regarding molecular functions, phenotypic effects, and adaptive significance. Many of them show strong pleiotropic effects. Here, we review examples of pleiotropy of flowering‐time genes and highlight those that also influence seed germination. Some genes appear to operate in the same genetic pathways when regulating both traits, whereas others show diversity of function in their regulation, either interacting with the same genetic partners but in different ways or potentially interacting with different partners. We discuss how functional diversification of pleiotropic genes in the regulation of different traits across the life cycle may mitigate evolutionary constraints of pleiotropy, permitting traits to respond more independently to environmental cues, and how it may even contribute to the evolutionary divergence of gene function across taxa. [ABSTRACT FROM AUTHOR]

Summary: In mammalians and yeast, the splicing factor U2AF65/Mud2p functions in precursor messenger RNA (pre‐mRNA) processing. Arabidopsis AtU2AF65b encodes a putative U2AF65 but its specific functions in plants are unknown. This paper examines the function of AtU2AF65b as a negative regulator of flowering time in Arabidopsis.We investigated the expression and function of AtU2AF65b in abscisic acid (ABA)‐regulated flowering as well as the transcript abundance and pre‐mRNA splicing of flowering‐related genes in the knock‐out mutants of AtU2AF65b.The atu2af65b mutants show early‐flowering phenotype under both long‐day and short‐day conditions. The transcript accumulation of the flowering repressor gene FLOWERING LOCUS C (FLC) is reduced in the shoot apex of atu2af65b, due to both increased intron retention and reduced transcription activation. Reduced transcription of FLC results, at least partially, from the abnormal splicing and reduced transcript abundance of ABSCISIC ACID‐INSENSITIVE 5 (ABI5), which encodes an activator of FLC in ABA‐regulated flowering signaling. Additionally, the expression of AtU2AF65b is promoted by ABA. Transition to flowering and splicing of FLC and ABI5 in the atu2af65b mutants are compromised during ABA‐induced flowering.ABA‐responsive AtU2AF65b functions in the pre‐mRNA splicing of FLC and ABI5 in shoot apex, whereby AtU2AF65b is involved in ABA‐mediated flowering transition in Arabidopsis. [ABSTRACT FROM AUTHOR]

Summary: Posttranslational histone modifications and the dynamics of histone variant H2A.Z are key mechanisms underlying the floral transition. In yeast, SWR1‐C and NuA4‐C mediate the deposition of H2A.Z and the acetylation of histone H4, H2A and H2A.Z, respectively. Yaf9 is a subunit shared by both chromatin‐remodeling complexes. The significance of the two Arabidopsis YAF9 homologues, YAF9A and YAF9B, is unknown.To get an insight into the role of Arabidopsis YAF9 proteins in plant developmental responses, we followed physiological, genetic, genomic, epigenetic, proteomics and cell biology approaches.Our data revealed that YAF9A and YAF9B are histone H3 readers with unequally redundant functions. Double mutant yaf9a yaf9b plants display pleiotropic developmental phenotypic alterations as well as misregulation of a wide variety of genes. We demonstrated that YAF9 proteins regulate flowering time by both FLC‐dependent and independent mechanisms that work in parallel with SWR1‐C. Interestingly, we show that YAF9A binds FLC chromatin and that YAF9 proteins regulate FLC expression by modulating the acetylation levels of H2A.Z and H4 but not H2A.Z deposition.Our work highlights the key role exerted by YAF9 homologues in the posttranslational modification of canonical histones and variants that regulate gene expression in plants to control development. [ABSTRACT FROM AUTHOR]

Summary: The role of the floral homeotic gene AGAMOUS (AG) and its close homologues in development of anemophilous, unisexual catkins has not previously been studied.We transformed two RNA interference (RNAi) constructs, PTG and its matrix‐attachment‐region flanked version MPG, into the early‐flowering female poplar clone 6K10 (Populus alba) to suppress the expression of its two duplicate AG orthologues.By early 2018, six out of 22 flowering PTG events and 11 out of 12 flowering MPG events showed modified floral phenotypes in a field trial in Oregon, USA. Flowers in catkins from modified events had 'carpel‐inside‐carpel' phenotypes. Complete disruption of seed production was observed in seven events, and sterile anther‐like organs in 10 events. Events with strong co‐suppression of both the two AG and two SEEDSTICK (STK) paralogues lacked both seeds and associated seed hairs. Alterations in all of the modified floral phenotypes were stable over 4 yr of study. Trees from floral‐modified events did not differ significantly (P < 0.05) from nonmodified transgenic or nontransgenic controls in biomass growth or leaf morphology.AG and STK genes show strong conservation of gene function during poplar catkin development and are promising targets for genetic containment of exotic or genetically engineered trees. [ABSTRACT FROM AUTHOR]

Contents Summary 35 I Overview of animal and plant WNK kinases 35 II. Structure: domains and topology 36 III. Phylogeny–evolutionary relationships 41 IV. Plant WNK kinase distribution and regulation of WNK expression and activity 41 V. Functions of WNK family members in physiology and development 41 VI. Say no more? Still many questions to be answered 45 Acknowledgements 46 References 46 Summary: WITH NO LYSINE (WNK) kinases are serine/threonine kinases uniquely characterized by an anomalous placement of a catalytic lysine, hence their moniker. In animals, WNK protein kinases play critical roles in protein trafficking of components that mediate renal ion transport processes and regulate osmoregulation of cell volume. In plants, the WNK kinase gene family is larger and more diverse. Recent studies revealed WNK kinase roles in orchestrating the trafficking of an ion channel, a lipid kinase complex in animals, and a heterotrimeric G protein signaling component in plants that is necessary for signal transduction. For this reason, new attention is geared toward investigating the mechanisms adopted by WNK kinases to nudge intracellular proteins to their destinations. In this review, the functions of WNK kinases in protein trafficking are derived from what we have learned from the model organism Arabidopsis thaliana. To place this new idea in context, we provide the predicted WNK kinase structures, their predicted expression patterns, a speculated evolutionary pathway, and the regulatory roles of plant WNKs in transport processes and other physiologies. We brazenly predict that the WNK kinases in both plants and animals will soon be recognized as a nexus for trafficking‐based signal transduction. [ABSTRACT FROM AUTHOR]

* Root knot nematodes (RKNs) penetrate into the root vascular cylinder, triggering morphogenetic changes to induce galls, de novo formed 'pseudo-organs' containing several giant cells (GCs). Distinctive gene repression events observed in early gall/GCs development are thought to be mediated by post-transcriptional silencing via microRNAs (miRNAs), a process that is far from being fully characterized. * Arabidopsis thaliana backgrounds with altered activities based on target 35S::MIMICRY172 (MIM172), 35S::TARGET OF EARLY ACTIVATION TAGGED 1 (TOE1)-miR172-resistant (35S::TOE1R) and mutant (flowering locus T-10 (ft-10)) lines were used for functional analysis of nematode infective and reproductive parameters. The GUS-reporter lines, MIR172A-E::GUS, treated with auxin (IAA) and an auxin-inhibitor (a-(phenyl ethyl-2-one)-indole-3-acetic acid (PEO-IAA)), together with the MIR172C AuxRE::GUS line with two mutated auxin responsive elements (AuxREs), were assayed for nematode-dependent gene expression. * Arabidopsis thaliana backgrounds with altered expression of miRNA172, TOE1 or FT showed lower susceptibility to the RKNs and smaller galls and GCs. MIR172C-D::GUS showed restricted promoter activity in galls/GCs that was regulated by auxins through auxin-responsive factors. IAA induced their activity in galls while PEO-IAA treatment and mutations in AuxRe motifs abolished it. * The results showed that the regulatory module miRNA172/TOE1/FT plays an important role in correct GCs and gall development, where miRNA172 is modulated by auxins. [ABSTRACT FROM AUTHOR]

Vernalisation requirement is an agriculturally important trait that postpones the development of cold-sensitive floral organs until the spring. The family Rosaceae includes many agriculturally important fruit and berry crops that suffer from crop losses caused by frost injury to overwintering flower buds. Recently, a vernalisation-requiring accession of the Rosaceae model woodland strawberry ( Fragaria vesca) has been identified in northern Norway. Understanding the molecular basis of the vernalisation requirement in this accession would advance the development of strawberry cultivars better adapted to temperate climate., We use gene silencing, gene expression analysis, genetic mapping and population genomics to study the genetic basis of the vernalisation requirement in woodland strawberry., Our results indicate that the woodland strawberry vernalisation requirement is endemic to northern Norwegian population, and mapping data suggest the orthologue of TERMINAL FLOWER1 ( Fv TFL1) as the causal floral repressor. We demonstrate that exceptionally low temperatures are needed to downregulate Fv TFL1 and to make these plants competent to induce flowering at low postvernalisation temperatures in the spring., We show that altered regulation of Fv TFL1 in the northern Norwegian woodland strawberry accession postpones flower induction until the spring, allowing plants to avoid winter injuries of flower buds that commonly occur in temperate regions. [ABSTRACT FROM AUTHOR]

Phenology is a key aspect of plant success. Recent research has demonstrated that herbarium specimens can provide important information on plant phenology. Massive digitization efforts have the potential to greatly expand herbarium-based phenological research, but also pose a serious challenge regarding efficient data collection., Here, we introduce CrowdCurio, a crowdsourcing tool for the collection of phenological data from herbarium specimens. We test its utility by having workers collect phenological data (number of flower buds, open flowers and fruits) from specimens of two common New England ( USA) species: Chelidonium majus and Vaccinium angustifolium. We assess the reliability of using nonexpert workers (i.e. Amazon Mechanical Turk) against expert workers. We also use these data to estimate the phenological sensitivity to temperature for both species across multiple phenophases., We found no difference in the data quality of nonexperts and experts. Nonexperts, however, were a more efficient way of collecting more data at lower cost. We also found that phenological sensitivity varied across both species and phenophases., Our study demonstrates the utility of CrowdCurio as a crowdsourcing tool for the collection of phenological data from herbarium specimens. Furthermore, our results highlight the insight gained from collecting large amounts of phenological data to estimate multiple phenophases. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Agustí et al., 225: 376–384. [ABSTRACT FROM AUTHOR]

Domestication of upland cotton ( Gossypium hirsutum) converted it from a lanky photoperiodic perennial to a day-neutral annual row-crop. Residual perennial traits, however, complicate irrigation and crop management, and more determinate architectures are desired. Cotton simultaneously maintains robust monopodial indeterminate shoots and sympodial determinate shoots. We questioned if and how the FLOWERING LOCUS T/ SINGLE FLOWER TRUSS ( SFT)-like and TERMINAL FLOWER1/ SELF- PRUNING ( SP)-like genes control the balance of monopodial and sympodial growth in a woody perennial with complex growth habit., Virus-based manipulation of Gh SP and Gh SFT expression enabled unprecedented functional analysis of cotton development., Gh SP maintains growth in all apices; in its absence, both monopodial and sympodial branch systems terminate precociously. Gh SFT encodes a florigenic signal stimulating rapid onset of sympodial branching and flowering in side shoots of wild photoperiodic and modern day-neutral accessions. High florigen concentrations did not alter monopodial apices, implying that once a cotton apex is SP-determined, it cannot be reset by florigen. Gh SP is also essential to establish and maintain cambial activity., Dynamic changes in Gh SFT and Gh SP levels navigate meristems between monopodial and sympodial programs in a single plant. SFT and SP influenced cotton domestication and are ideal targets for further agricultural optimization. [ABSTRACT FROM AUTHOR]

As a key epigenetic modification, the methylation of histone H3 lysine 36 (H3K36) modulates chromatin structure and is involved in diverse biological processes., To better understand the language of H3K36 methylation in rice ( Oryza sativa), we chose potential histone methylation enzymes for functional exploration. In particular, we characterized rice SET DOMAIN GROUP 708 ( SDG708) as an H3K36-specific methyltransferase possessing the ability to deposit up to three methyl groups on H3K36., Compared with the wild-type, SDG708-knockdown rice mutants displayed a late-flowering phenotype under both long-day and short-day conditions because of the down-regulation of the key flowering regulatory genes Heading date 3a ( Hd3a), RICE FLOWERING LOCUS T1 ( RFT1), and Early heading date 1 ( Ehd1). Chromatin immunoprecipitation experiments indicated that H3K36me1, H3K36me2, and H3K36me3 levels were reduced at these loci in SDG708-deficient plants. More importantly, SDG708 was able to directly target and effect H3K36 methylation on specific flowering genes. In fact, knockdown of SDG708 led to misexpression of a set of functional genes and a genome-wide decrease in H3K36me1/2/3 levels during the early growth stages of rice., SDG708 is a methyltransferase that catalyses genome-wide deposition of all three methyl groups on H3K36 and is involved in many biological processes in addition to flowering promotion. [ABSTRACT FROM AUTHOR]

Phenological changes among plants due to climate change are well documented, but often hard to interpret. In order to assess the adaptive value of observed changes, we study how annual plants with and without growth constraints should optimize their flowering time when productivity and season length changes. We consider growth constraints that depend on the plant's vegetative mass: self-shading, costs for nonphotosynthetic structural tissue and sibling competition., We derive the optimal flowering time from a dynamic energy allocation model using optimal control theory. We prove that an immediate switch (bang-bang control) from vegetative to reproductive growth is optimal with constrained growth and constant mortality., Increasing mean productivity, while keeping season length constant and growth unconstrained, delayed the optimal flowering time. When growth was constrained and productivity was relatively high, the optimal flowering time advanced instead. When the growth season was extended equally at both ends, the optimal flowering time was advanced under constrained growth and delayed under unconstrained growth., Our results suggests that growth constraints are key factors to consider when interpreting phenological flowering responses. It can help to explain phenological patterns along productivity gradients, and links empirical observations made on calendar scales with life-history theory. [ABSTRACT FROM AUTHOR]

Germination timing influences plant fitness, and its sensitivity to temperature may cause it to change as climate shifts. These changes are likely to be complex because temperatures that occur during seed maturation and temperatures that occur post-dispersal interact to define germination timing., We used the model organism Arabidopsis thaliana to determine how flowering time (which defines seed-maturation temperature) and post-dispersal temperature influence germination and the expression of genetic variation for germination., Germination responses to temperature (germination envelopes) changed as seeds aged, or after-ripened, and these germination trajectories depended on seed-maturation temperature and genotype. Different combinations of genotype, seed-maturation temperature, and after-ripening produced similar germination envelopes. Likewise, different genotypes and seed-maturation temperatures combined to produce similar germination trajectories. Differences between genotypes were most likely to be observed at high and low germination temperatures., The germination behavior of some genotypes responds weakly to maternal temperature but others are highly plastic. We hypothesize that weak dormancy induction could synchronize germination of seeds dispersed at different times. By contrast, we hypothesize that strongly responsive genotypes may spread offspring germination over several possible germination windows. Considering germination responses to temperature is important for predicting phenology expression and evolution in future climates. [ABSTRACT FROM AUTHOR]

As a step toward functional annotation of genes required for floral initiation and development within the Eucalyptus genome, we used short read sequencing to analyze transcriptomes of floral buds from early and late developmental stages, and compared these with transcriptomes of diverse vegetative tissues, including leaves, roots, and stems., A subset of 4807 genes (13% of protein-coding genes) were differentially expressed between floral buds of either stage and vegetative tissues. A similar proportion of genes were differentially expressed among all tissues. A total of 479 genes were differentially expressed between early and late stages of floral development. Gene function enrichment identified 158 gene ontology classes that were overrepresented in floral tissues, including 'pollen development' and 'aromatic compound biosynthetic process'. At least 40 floral-dominant genes lacked functional annotations and thus may be novel floral transcripts., We analyzed several genes and gene families in depth, including 49 putative biomarkers of floral development, the MADS-box transcription factors, 'S-domain'-receptor-like kinases, and selected gene family members with phosphatidylethanolamine-binding protein domains. Expanded MADS-box gene subfamilies in Eucalyptus grandis included SUPPRESSOR OF OVEREXPRESSION OF CO 1 ( SOC1), SEPALLATA ( SEP) and SHORT VEGETATIVE PHASE ( SVP) Arabidopsis thaliana homologs., These data provide a rich resource for functional and evolutionary analysis of genes controlling eucalypt floral development, and new tools for breeding and biotechnology. [ABSTRACT FROM AUTHOR]

Posttranslational acetylation of histones is reversibly regulated by histone deacetylases ( HDACs). Despite the evident significance of HDACs in Arabidopsis development, the biological roles and underlying molecular mechanisms of many HDACs are yet to be elucidated., By a reverse-genetic approach, we isolated an hda9 mutant and performed phenotypic analyses on it. In order to address the role of HDA9 in flowering, genetic, molecular, and biochemical approaches were employed., hda9 flowered early under noninductive short-day ( SD) conditions and had increased expression of the floral integrator FLOWERING LOCUS T ( FT) and the floral activator AGAMOUS- LIKE 19 ( AGL19) compared with the wild-type. The hda9 mutation increased histone acetylation and RNA polymerase II occupancy at AGL19 but not at FT during active transcription, and the HDA9 protein directly targeted AGL19. AGL19 expression was higher under SD than under inductive long-day (LD) conditions, and an AGL19 overexpression caused a strong up-regulation of FT. A genetic analysis showed that an agl19 mutation is epistatic to the hda9 mutation, masking both the early flowering and the increased FT expression of hda9., Taken together, our data indicate that HDA9 prevents precocious flowering under SD conditions by curbing the hyperactivation of AGL19, an upstream activator of FT, through resetting the local chromatin environment. [ABSTRACT FROM AUTHOR]

Different genotypes often exhibit opposite plastic responses in the timing of the onset of flowering with increasing plant density. In experimental studies, selection for accelerated flowering is generally found. By contrast, game theoretical studies predict that there should be selection for delayed flowering when competition increases., Combining different optimality criteria, the conditions under which accelerated or delayed flowering in response to density would be selected for are analysed with a logistic growth simulation model., To maximize seed production at the whole-stand level (simple optimization), selection should lead to accelerated flowering at high plant density, unless very short growing seasons select for similar onset of flowering at all densities. By contrast, selection of relative individual fitness will lead to delayed flowering when season length is long and/or growth rates are high., These different results give a potential explanation for the observed differences in direction of the plastic responses within and between species, including homeostasis, as a result of the effect of the variation in season length on the benefits of delayed flowering. This suggests that limited plasticity can evolve without the costs and limits that are currently thought to constrain the evolution of plasticity. [ABSTRACT FROM AUTHOR]

FT/ TFL1 family members have been known to be involved in the development and flowering in plants. In rose, Ro KSN, a TFL1 homologue, is a key regulator of flowering, whose absence causes continuous flowering. Our objectives are to functionally validate Ro KSN and to explore its mode of action in rose., We complemented Arabidopsis tfl1 mutants and ectopically expressed Ro KSN in a continuous-flowering (CF) rose. Using different protein interaction techniques, we studied Ro KSN interactions with Ro FD and Ro FT and possible competition., In Arabidopsis, Ro KSN complemented the tfl1 mutant by rescuing late flowering and indeterminate growth. In CF roses, the ectopic expression of Ro KSN led to the absence of flowering. Different branching patterns were observed and some transgenic plants had an increased number of leaflets per leaf. In these transgenic roses, floral activator transcripts decreased. Furthermore, Ro KSN was able to interact both with Ro FD and the floral activator, Ro FT. Protein interaction experiments revealed that Ro KSN and Ro FT could compete with Ro FD for repression and activation of blooming, respectively., We conclude that Ro KSN is a floral repressor and is also involved in the vegetative development of rose. Ro KSN forms a complex with Ro FD and could compete with Ro FT for repression of flowering. [ABSTRACT FROM AUTHOR]

The Bruno RNA-binding protein (RBP) has been shown to initially repress the translation of oskar mRNA during Drosophila oogenesis and later to be involved in a broad range of RNA regulation., Here, we show that homologous constitutive overexpression of each of two Arabidopsis thaliana Bruno-like genes, AtBRN1 and AtBRN2, delayed the flowering time, while the atbrn1 atbrn2-3 double mutant flowered early and exhibited increased expression of APETALA1 ( AP1) and LEAFY ( LFY) transcripts., Crossing of 35S::AtBRNs with SOC1 101-D plants demonstrated that 35S::AtBRNs suppress an early-flowering phenotype of SOC1 101-D in which the coding sequence ( CDS) with the 3′ UTR of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 ( SOC1) gene is overexpressed. However, this early-flowering phenotype by SOC1 overexpression was maintained in the plants coexpressing 35S::AtBRNs and 35S:: SOC1 without the 3′ UTR ( -3′ UTR)., Using yeast three-hybrid, electrophoretic mobility shift, RNA immunoprecipitation, and protoplast transient assays, we found that AtBRNs bind to the 3′ UTR of SOC1 RNA and participate in mRNA decay, which was mediated by the distal region of the SOC1 3′ UTR. Overall, AtBRNs repress SOC1 activity in a 3′ UTR-dependent manner, thereby controlling the flowering time in Arabidopsis. [ABSTRACT FROM AUTHOR]

FLOWERING LOCUS T ( FT) and CENTRORADIALIS ( CEN) homologs have been implicated in regulation of growth, determinacy and flowering., The roles of kiwifruit FT and CEN were explored using a combination of expression analysis, protein interactions, response to temperature in high-chill and low-chill kiwifruit cultivars and ectopic expression in Arabidopsis and Actinidia., The expression and activity of FT was opposite from that of CEN and incorporated an interaction with a FLOWERING LOCUS D ( FD)-like bZIP transcription factor. Accumulation of FT transcript was associated with plant maturity and particular stages of leaf, flower and fruit development, but could be detected irrespective of the flowering process and failed to induce precocious flowering in transgenic kiwifruit. Instead, transgenic plants demonstrated reduced growth and survival rate. Accumulation of FT transcript was detected in dormant buds and stem in response to winter chilling. In contrast, FD in buds was reduced by exposure to cold. CEN transcript accumulated in developing latent buds, but declined before the onset of dormancy and delayed flowering when ectopically expressed in kiwifruit., Our results suggest roles for FT, CEN and FD in integration of developmental and environmental cues that affect dormancy, budbreak and flowering in kiwifruit. [ABSTRACT FROM AUTHOR]

The study of the evolutionary and population genetics of quantitative traits requires the assessment of within- and among-population patterns of variation., We carried out experiments including eight Iberian Arabidopsis thaliana populations (10 individuals per population) in glasshouse and field conditions. We quantified among- and within-population variation for flowering time and for several field life-history traits. Individuals were genotyped with microsatellites, single nucleotide polymorphisms and four well-known flowering genes ( FRI, FLC, CRY 2 and PHYC). Phenotypic and genotypic data were used to conduct QST- FST comparisons., Life-history traits varied significantly among- and within-populations. Flowering time also showed substantial within- and among-population variation as well as significant genotype × environment interactions among the various conditions. Individuals bearing FRI truncations exhibited reduced recruitment in field conditions and differential flowering time behavior across experimental conditions, suggesting that FRI contributes to the observed significant genotype × environment interactions. Flowering time estimated in field conditions was the only trait showing significantly higher quantitative genetic differentiation than neutral genetic differentiation values., Overall, our results show that these A. thaliana populations are genetically more differentiated for flowering time than for neutral markers, suggesting that flowering time is likely to be under divergent selection. [ABSTRACT FROM AUTHOR]

Arabis alpina is a polycarpic perennial, in which PERPETUAL FLOWERING1 (PEP1) regulates flowering and perennial traits in a vernalization-dependent manner. Mutagenesis screens of the pep1 mutant established the role of other flowering time regulators in PEP1-parallel pathways. Here we characterized three allelic enhancers of pep1 (eop002, 085 and 091) which flower early. We mapped the causal mutations and complemented mutants with the identified gene. Using quantitative reverse transcriptase PCR and reporter lines, we determined the protein spatiotemporal expression patterns and localization within the cell. We also characterized its role in Arabidopsis thaliana using CRISPR and in A. alpina by introgressing mutant alleles into a wild-type background. These mutants carried lesions in an AAA + ATPase of unknown function, FLOWERING REPRESSOR AAA + ATPase 1 (AaFRAT1). AaFRAT1 was detected in the vasculature of young leaf primordia and the rib zone of flowering shoot apical meristems. At the subcellular level, AaFRAT1 was localized at the interphase between the endoplasmic reticulum and peroxisomes. Introgression lines carrying Aafrat1 alleles required less vernalization to flower and reduced number of vegetative axillary branches. By contrast, A. thaliana CRISPR lines showed weak flowering phenotypes. AaFRAT1 contributes to flowering time regulation and the perennial growth habit of A. alpina., (© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.)

FLOWERING LOCUS C ( FLC) is one of the main genes influencing the vernalization requirement and natural flowering time variation in the annual Arabidopsis thaliana. Here we studied the effects of vernalization on flowering and its genetic basis in the perennial Arabidopsis lyrata., Two tandemly duplicated FLC genes ( FLC1 and FLC2) were compared with respect to expression and DNA sequence. The effect of vernalization on flowering and on the expression of FLC1 was studied in three European populations. The genetic basis of the FLC1 expression difference between two of the populations was further studied by expression quantitative trait locus ( eQTL) mapping and sequence analysis., FLC1 was shown to have a likely role in the vernalization requirement for flowering in A. lyrata. Vernalization decreased its expression and the northern study populations showed higher FLC1 expression than the southern one. eQTL mapping between two of the populations revealed one eQTL affecting FLC1 expression in the genomic region containing the FLC genes. Most FLC1 sequence differences between the study populations were found in the promoter region and in the first intron., Variation in the FLC1 sequence may cause differences in FLC1 expression between late- and early-flowering A. lyrata populations. [ABSTRACT FROM AUTHOR]