Transcriptional Regulators of Plant Adaptation to Heat Stress.

Heat stress (HS) is becoming an increasingly large problem for food security as global warming progresses. As sessile species, plants have evolved different mechanisms to cope with the disruption of cellular homeostasis, which can impede plant growth and development. Here, we summarize the mechanisms underlying transcriptional regulation mediated by transcription factors, epigenetic regulators, and regulatory RNAs in response to HS.

Misexpression Approaches for the Manipulation of Flower Development.

The generation of dominant gain-of-function mutants through activation tagging is a forward genetic approach that can be applied to study the mechanisms of flower development, complementing the screening of loss-of-function mutants. In addition, the functions of genes of interest can be further analyzed through reverse genetics. A commonly used method is gene overexpression, where ectopic expression can result in an opposite phenotype to that caused by a loss-of-function mutation.

Histone Demethylases JMJ30 and JMJ32 Modulate the Speed of Vernalization Through the Activation of in .

Vernalization is the promotion of flowering after prolonged exposure to cold. In , vernalization induces epigenetic silencing of the floral repressor gene (). Among the repressive epigenetic marks, the trimethylation of lysine 27 on histone H3 proteins (H3K27me3) is a critical contributor to the epigenetic silencing of .

H3K27me3 demethylases alter HSP22 and HSP17.6C expression in response to recurring heat in Arabidopsis.

Acclimation to high temperature increases plants' tolerance of subsequent lethal high temperatures. Although epigenetic regulation of plant gene expression is well studied, how plants maintain a memory of environmental changes over time remains unclear. Here, we show that JUMONJI (JMJ) proteins, demethylases involved in histone H3 lysine 27 trimethylation (H3K27me3), are necessary for Arabidopsis thaliana heat acclimation.

Identification of a Devernalization Inducer by Chemical Screening Approaches in .

Vernalization is the promotion of flowering after prolonged exposure to cold. In , vernalization induces epigenetic silencing of the floral repressor gene (). The repressive epigenetic mark trimethylation of lysine 27 on histone H3 proteins (H3K27me3) is a critical contributor to the epigenetic silencing of .

When to stop: an update on molecular mechanisms of floral meristem termination.

Flowers have fascinated humans for millennia, not only because of their beauty, but also because they give rise to fruits, from which most agricultural products are derived. In most angiosperms, the number and position of floral organs are morphologically and genetically defined, and their development is tightly controlled by complex regulatory networks to ensure reproductive success. How flower development is temporally initiated and spatially maintained has been widely researched.

In Situ Proximity Ligation Assay to Detect the Interaction Between Plant Transcription Factors and Other Regulatory Proteins.

In plants, a lot of transcription factors fulfill their roles in gene regulation through the interaction with other regulatory proteins and co-factors. Thus, confirmation of protein-protein interaction is key to understand the precise function of transcription factors. Many methods have been developed to investigate the protein-protein interaction in vivo and in vitro.

SUPERMAN regulates floral whorl boundaries through control of auxin biosynthesis.

Proper floral patterning, including the number and position of floral organs in most plant species, is tightly controlled by the precise regulation of the persistence and size of floral meristems (FMs). In , two known feedback pathways, one composed of WUSCHEL (WUS) and CLAVATA3 (CLV3) and the other composed of AGAMOUS (AG) and WUS, spatially and temporally control floral stem cells, respectively. However, mounting evidence suggests that other factors, including phytohormones, are also involved in floral meristem regulation.

Dynamics of H3K27me3 methylation and demethylation in plant development.

Epigenetic regulation controls multiple aspects of the plant development. The N-terminal tail of histone can be differently modified to regulate various chromatin activities. One of them, the trimethylation of histone H3 lysine 27 (H3K27me3) confers a repressive chromatin state with gene silencing.

Co-ordination of Flower Development Through Epigenetic Regulation in Two Model Species: Rice and Arabidopsis.

Angiosperms produce flowers for reproduction. Flower development is a multistep developmental process, beginning with the initiation of the floral meristems, followed by floral meristem identity specification and maintenance, organ primordia initiation, floral organ identity specification, floral stem cell termination and finally floral organ maturation. During flower development, each of a large number of genes is expressed in a spatiotemporally regulated manner.

Jumonji demethylases moderate precocious flowering at elevated temperature via regulation of FLC in Arabidopsis.

As sessile organisms, plants have evolved multiple mechanisms to respond to environmental changes to improve survival. Arabidopsis plants show accelerated flowering at increased temperatures. Here we show that Jumonji-C domain-containing protein JMJ30 directly binds to the flowering-repressor FLOWERING LOCUS C (FLC) locus and removes the repressive histone modification H3 lysine 27 trimethylation (H3K27me3).

Arabidopsis MRG domain proteins bridge two histone modifications to elevate expression of flowering genes.

Trimethylation of lysine 36 of histone H3 (H3K36me3) is found to be associated with various transcription events. In Arabidopsis, the H3K36me3 level peaks in the first half of coding regions, which is in contrast to the 3'-end enrichment in animals. The MRG15 family proteins function as 'reader' proteins by binding to H3K36me3 to control alternative splicing or prevent spurious intragenic transcription in animals.

Timing mechanism dependent on cell division is invoked by Polycomb eviction in plant stem cells.

Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay.

Misexpression approaches for the manipulation of flower development.

The generation of dominant gain-of-function mutants through activation tagging is a forward genetic approach that complements the screening of loss-of-function mutants and that has been successfully applied to studying the mechanisms of flower development. In addition, the functions of genes of interest can be further analyzed through reverse genetics. A commonly used method is gene overexpression, where strong, often ectopic expression can result in an opposite phenotype to that caused by a loss-of-function mutation.

Functional roles of histone modification, chromatin remodeling and microRNAs in Arabidopsis flower development.

Flowers are the reproductive units of angiosperms and originate from small number of stem cells maintained at the growing tips of shoots. Flower development is a multistep process starting from an environmental response, followed by the meristem identity change, termination of the stem cell activity, organ polarity control, organ identity determination, and organogenesis. It is regulated through many hard-wired genetic pathways, composed of transcription factors, signaling molecules, catalytic enzymes, and structural proteins.

Flowering and genome integrity control by a nuclear matrix protein in Arabidopsis.

The matrix attachment regions (MARs) binding proteins could finely orchestrate temporal and spatial gene expression during development. In Arabidopsis, transposable elements (TEs) and TE-like repeat sequences are transcriptionally repressed or attenuated by the coordination of many key players including DNA methyltransferases, histone deacetylases, histone methyltransferases and the siRNA pathway, which help to protect genomic integrity and control multiple developmental processes such as flowering. We have recently reported that an AT-hook nuclear matrix binding protein, TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK), participates in a histone deacetylation (HDAC) complex to silence TEs and genes containing a TE-like sequence, including AtMu1, FWA and FLOWERING LOCUS C (FLC) in Ler background.

The AT-hook/PPC domain protein TEK negatively regulates floral repressors including MAF4 and MAF5.

Epigenetic regulations of transposable elements (TEs) and TE-like repeat sequences help to protect genomic integrity and control various developmental processes, including flowering time. This complex action of gene silencing requires the coordination of many key players including DNA methylases, histone deacetylases and histone methyltranferases. We have recently reported that an AT-hook DNA binding protein, TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK), participates in silencing TEs and TE-like sequence containing genes, such as Ler FLOWERING LOCUS C (FLC) and FWA.

A matrix protein silences transposons and repeats through interaction with retinoblastoma-associated proteins.

Epigenetic regulation helps to maintain genomic integrity by suppressing transposable elements (TEs) and also controls key developmental processes, such as flowering time. To prevent TEs from causing rearrangements and mutations, TE and TE-like repetitive DNA sequences are usually methylated, whereas histones are hypoacetylated and methylated on specific residues (e.g.