Many plants require prolonged exposure to cold to acquire the competence to flower. The process by which cold exposure results in competence is known as vernalization. In
Vernalization accelerates flowering after prolonged winter cold. Transcriptional and epigenetic changes are known to be involved in the regulation of the vernalization response. Despite intensive applications of next‐generation sequencing in diverse aspects of plant research, genome‐wide transcriptome and epigenome profiling during the vernalization response has not been conducted. In this work, to our knowledge, we present the first comprehensive analyses of transcriptomic and epigenomic dynamics during the vernalization process in
- Award ID(s):
- 1656764
- NSF-PAR ID:
- 10449689
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 103
- Issue:
- 4
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 1490-1502
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary Arabidopsis thaliana , vernalization leads to the stable repression of the floral repressor via chromatin modification, including an increase of trimethylation on lysine 27 of histone H3 (H3K27me3) by Polycomb Repressive Complex 2 (FLOWERING LOCUS CPRC 2). Vernalization in pooids is associated with the stable induction of a floral promoter, (VERNALIZATION 1VRN1 ). From a screen for mutants with a reduced vernalization requirement in the model grassBrachypodium distachyon , we identified two recessive alleles of (ENHANCER OF ZESTE ‐LIKE 1 ).EZL 1 is orthologous toEZL 1A. thaliana , a gene that encodes the catalytic subunit ofCURLY LEAF 1PRC 2.B. distachyon ezl1 mutants flower rapidly without vernalization in long‐day (LD ) photoperiods; thus, is required for the proper maintenance of the vegetative state prior to vernalization. Transcriptomic studies inEZL 1ezl1 revealed mis‐regulation of thousands of genes, including ectopic expression of several floral homeotic genes in leaves. Loss of results in the global reduction of H3K27me3 and H3K27me2, consistent with this gene making a major contribution toEZL 1PRC 2 activity inB. distachyon . Furthermore, inezl1 mutants, the flowering genes andVRN 1 (AGAMOUS ) are ectopically expressed and have reduced H3K27me3. Artificial microAG RNA knock‐down of either orVRN 1 inAG ezl1‐1 mutants partially restores wild‐type flowering behavior in non‐vernalized plants, suggesting that ectopic expression inezl1 mutants may contribute to the rapid‐flowering phenotype. -
SUMMARY Flowering of the reference legume
Medicago truncatula is promoted by winter cold (vernalization) followed by long‐day photoperiods (VLD) similar to winter annual Arabidopsis. However, Medicago lacksFLC andCO , key regulators of Arabidopsis VLD flowering. Most plants have twoINHIBITOR OF GROWTH (ING ) genes (ING1 andING2 ), encoding proteins with an ING domain with two anti‐parallel alpha‐helices and a plant homeodomain (PHD) finger, but their genetic role has not been previously described. In Medicago,Mting1 gene‐edited mutants developed and flowered normally, but anMting2‐1 Tnt1 insertion mutant and gene‐editedMting2 mutants had developmental abnormalities including delayed flowering particularly in VLD, compact architecture, abnormal leaves with extra leaflets but no trichomes, and smaller seeds and barrels.Mting2 mutants had reduced expression of activators of flowering, including theFT ‐like geneMtFTa1 , and increased expression of the candidate repressorMtTFL1c , consistent with the delayed flowering of the mutant.MtING2 overexpression complementedMting2‐1 , but did not accelerate flowering in wild type. The MtING2 PHD finger bound H3K4me2/3 peptides weaklyin vitro , but analysis of gene‐edited mutants indicated that it was dispensable to MtING2 function in wild‐type plants. RNA sequencing experiments indicated that >7000 genes are mis‐expressed in theMting2‐1 mutant, consistent with its strong mutant phenotypes. Interestingly, ChIP‐seq analysis identified >5000 novel H3K4me3 locations in the genome ofMting2‐1 mutants compared to wild type R108. Overall, our mutant study has uncovered an important physiological role of a plantING2 gene in development, flowering, and gene expression, which likely involves an epigenetic mechanism. -
Abstract Conservative flowering behaviours, such as flowering during long days in summer or late flowering at a high leaf number, are often proposed to protect against variable winter and spring temperatures which lead to frost damage if premature flowering occurs. Yet, due the many factors in natural environments relative to the number of individuals compared, assessing which climate characteristics drive these flowering traits has been difficult. We applied a multidisciplinary approach to 10 winter‐annual
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Burbank, Lindsey Price (Ed.)
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Cross‐species systems analysis of evolutionary toolkits of neurogenomic response to social challenge
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