Vernalization-mediated chromatin changes

Zografos, Brett R.; Sung, Sibum

doi:10.1093/jxb/ers157

Cited by 30 publications

(19 citation statements)

References 49 publications

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“…FLC expression is regulated by a complex network involving epigenetic regulators, such as Polycomb Repressive Complex (PRC) components, in response to flowering signals in autonomous, vernalization, and other vernalization-independent pathways (Clarke and Dean, 1994;Johanson et al, 2000;Zhang and van Nocker, 2002;Michaels et al, 2004;Simpson, 2004;Kim et al, 2009;He, 2012;Zografos and Sung, 2012;Kim and Sung, 2014). Thus, we examined the expression of those known upstream regulators of FLC in 9-d-old wild-type and top1a-10 seedlings.…”

Section: Top1a Directly Controls Flc Expressionmentioning

confidence: 99%

DNA Topoisomerase Iα Affects the Floral Transition

et al. 2016

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ORCID ID: 0000-0002-9778-8855 (H.Y.).DNA topoisomerases modulate DNA topology to maintain chromosome superstructure and genome integrity, which is indispensable for DNA replication and RNA transcription. Their function in plant development still remains largely unknown. Here, we report a hitherto unidentified role of Topoisomerase Ia (TOP1a) in controlling flowering time in Arabidopsis (Arabidopsis thaliana). Loss of function of TOP1a results in early flowering under both long and short days. This is attributed mainly to a decrease in the expression of a central flowering repressor, FLOWERING LOCUS C (FLC), and its close homologs, MADS AFFECTING FLOWERING4 (MAF4) and MAF5, during the floral transition. TOP1a physically binds to the genomic regions of FLC, MAF4, and MAF5 and promotes the association of RNA polymerase II complexes to their transcriptional start sites. These correlate with the changes in histone modifications but do not directly affect nucleosome occupancy at these loci. Our results suggest that TOP1a mediates DNA topology to facilitate the recruitment of RNA polymerase II at FLC, MAF4, and MAF5 in conjunction with histone modifications, thus facilitating the expression of these key flowering repressors to prevent precocious flowering in Arabidopsis.

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Section: Top1a Directly Controls Flc Expressionmentioning

confidence: 99%

DNA Topoisomerase Iα Affects the Floral Transition

et al. 2016

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“…Notably, a number of genes are rapidly induced by above-freezing cold temperatures to trigger cold acclimation in plants (Thomashow, 2001;Chinnusamy et al, 2007). Vernalization is similar to cold acclimation in that both responses are triggered by similar above-freezing temperatures (Lang, 1965;Bond et al, 2011;Zografos and Sung, 2012). However, there are two major differences.…”

Section: Vernalization As a Response To Cold Temperaturesmentioning

confidence: 98%

“…In addition, vernalization requires longer period of cold exposure than cold acclimation. For example, cold acclimation can be achieved within days of cold exposure whereas vernalization needs 4~6 weeks of cold exposure in Arabidopsis (Lang, 1965;Bond et al, 2011;Zografos and Sung, 2012). This is an adaptive feature of the vernalization response to ensure that plants respond to winter cold, but not to fluctuating temperatures.…”

Section: Vernalization As a Response To Cold Temperaturesmentioning

confidence: 99%

Genetic and Epigenetic Mechanisms Underlying Vernalization

Kim

Sung

2014

The Arabidopsis Book

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Plants have evolved a number of monitoring systems to sense their surroundings and to coordinate their growth and development accordingly. Vernalization is one example, in which flowering is promoted after plants have been exposed to a long-term cold temperature (i.e. winter). Vernalization results in the repression of floral repressor genes that inhibit the floral transition in many plant species. Here, we describe recent advances in our understanding of the vernalization-mediated promotion of flowering in Arabidopsis and other flowering plants. In Arabidopsis, the vernalization response includes the recruitment of chromatin-modifying complexes to floral repressors and thus results in the enrichment of repressive histone marks that ensure the stable repression of floral repressor genes. Changes in histone modifications at floral repressor loci are stably maintained after cold exposure, establishing the competence to flower the following spring. We also discuss similarities and differences in regulatory circuits in vernalization responses among Arabidopsis and other plants.

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“…Signals from the vernalization pathway, photoperiod pathway, autonomous pathway, GA pathway, and plant age all contribute to ensuring the correct timing of flowering Wellmer and Riechmann, 2010;Srikanth and Schmid, 2011). Within the vernalization pathway, a number of key players have been identified (Andrés and Coupland, 2012;Schmitz and Amasino, 2012;Song et al, 2012;Zografos and Sung, 2012). In winter annuals, a functional FRIGIDA (FRI) allele is required to activate FLOWERING LOCUS C (FLC).…”

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confidence: 99%

“…FLC strongly suppresses the flowering promoters FLOWERING LOCUS T (FT) and AGAMOUS LIKE20 (AGL20; also referred to as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1) and thus inhibits flowering. During vernalization, VERNALIZATION INSENSITIVE3 (VIN3) represses FLC, and the repressed state is maintained in subsequent warm periods by epigenetic silencing (Crevillén and Dean, 2011;Zografos and Sung, 2012), allowing FT, AGL20, and, through positive feedback with AGL20, AGL24 (Liu et al, 2008) to initiate flowering. Many natural populations and most laboratory accessions, among them Columbia-0 (Col-0), carry nonfunctional FRI or FLC alleles and thus respond only weakly to vernalization, resulting in fast flowering, summer-annual life cycles (Johanson et al, 2000;Gazzani et al, 2003;Shindo et al, 2005).…”

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confidence: 99%

Gene Regulatory Variation Mediates Flowering Responses to Vernalization along an Altitudinal Gradient in Arabidopsis

et al. 2014

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Steep environmental gradients provide ideal settings for studies of potentially adaptive phenotypic and genetic variation in plants. The accurate timing of flowering is crucial for reproductive success and is regulated by several pathways, including the vernalization pathway. Among the numerous genes known to enable flowering in response to vernalization, the most prominent is FLOWERING LOCUS C (FLC). FLC and other genes of the vernalization pathway vary extensively among natural populations and are thus candidates for the adaptation of flowering time to environmental gradients such as altitude. We used 15 natural Arabidopsis (Arabidopsis thaliana) genotypes originating from an altitudinal gradient (800-2,700 m above sea level) in the Swiss Alps to test whether flowering time correlated with altitude under different vernalization scenarios. Additionally, we measured the expression of 12 genes of the vernalization pathway and its downstream targets. Flowering time correlated with altitude in a nonlinear manner for vernalized plants. Flowering time could be explained by the expression and regulation of the vernalization pathway, most notably by AGAMOUS LIKE19 (AGL19), FLOWERING LOCUS T (FT), and FLC. The expression of AGL19, FT, and VERNALIZATION INSENSITIVE3 was associated with altitude, and the regulation of MADS AFFECTING FLOWERING2 (MAF2) and MAF3 differed between low-and highaltitude genotypes. In conclusion, we found clinal variation across an altitudinal gradient both in flowering time and the expression and regulation of genes in the flowering time control network, often independent of FLC, suggesting that the timing of flowering may contribute to altitudinal adaptation.

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Vernalization-mediated chromatin changes

Cited by 30 publications

References 49 publications

DNA Topoisomerase Iα Affects the Floral Transition

DNA Topoisomerase Iα Affects the Floral Transition

Genetic and Epigenetic Mechanisms Underlying Vernalization

Gene Regulatory Variation Mediates Flowering Responses to Vernalization along an Altitudinal Gradient in Arabidopsis

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