Epigenetic control of plant senescence and linked processes
TL;DR: The review outlines the concept of epigenetic control of interconnected regulatory pathways steering stress responses and plant development and summarizes recent findings on global alterations in chromatin structure, histone and DNA modifications, and ATP-dependent chromatin remodelling during plant senescence and linked processes.
Abstract: Senescence processes are part of the plant developmental programme. They involve reprogramming of gene expression and are under the control of a complex regulatory network closely linked to other developmental and stressresponsive pathways. Recent evidence indicates that leaf senescence is regulated via epigenetic mechanisms. In the present review, the epigenetic control of plant senescence is discussed in the broader context of environmentsensitive plant development. The review outlines the concept of epigenetic control of interconnected regulatory pathways steering stress responses and plant development. Besides giving an overview of techniques used in the field, it summarizes recent findings on global alterations in chromatin structure, histone and DNA modifications, and ATPdependent chromatin remodelling during plant senescence and linked processes.
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TL;DR: The Oncidium Gower Ramsey orchid is both an important cut flower plant and a potential good model plant for study the ethylene-sensitive floral senescence.
Abstract: The Oncidium Gower Ramsey orchid is both an important cut flower plant and a potential good model plant for study the ethylene-sensitive floral senescence. Though significant progress has been made...
4 citations
TL;DR: The results demonstrate that DcATX1 is a H3K4 methyltransferase that promotes the expression of DcWRKY75, DcACO1 and DcSAG12 by regulating H 3K4me3 levels, thereby accelerating ethylene induced petal senescence in carnation.
Abstract: Petal senescence is controlled by a complex regulatory network. Epigenetic regulation like histone modification influences chromatin state and gene expression. However, involvement of histone methylation in regulating petal senescence is still largely unknown. Here, we found that the trimethylation of histone H3 at Lysine 4 (H3K4me3) is increased during the ethylene induced petal senescence in carnation (Dianthus caryophyllus L.). The H3K4me3 levels are positively associated with the expression of transcription factor DcWRKY75, ethylene biosynthetic genes DcACS1 and DcACO1, and senescence associated genes (SAGs) DcSAG12 and DcSAG29. Further, we identified that carnation DcATX1 (ARABIDOPSIS HOMOLOG OF TRITHORAX1) encodes a histone lysine methyltransferase which can methylate H3K4. Knockdown of DcATX1 delays ethylene induced petal senescence in carnation, which is associated with the downregulated expression of DcWRKY75, DcACO1 and DcSAG12. While overexpression of DcATX1 exhibits the opposite effects. DcATX1 promotes the transcription of DcWRKY75, DcACO1 and DcSAG12 by targeting to their promoters to elevate the H3K4me3 levels. Overall, our results demonstrate that DcATX1 is a H3K4 methyltransferase that promotes the expression of DcWRKY75, DcACO1 and DcSAG12 by regulating H3K4me3 levels, thereby accelerating ethylene induced petal senescence in carnation. This study further indicates that epigenetic regulation is important for plant senescence process. One sentence summary A histone methyltransferase promotes ethylene induced petal senescence in cut flower
4 citations
TL;DR: How HEB downregulation negatively affects the progression of senescence, resulting in changes in transcription of senescing-promoting genes, as well as the activity of enzymes involved in chlorophyll degradation, thereby explaining the stay-green phenotype is described.
Abstract: Leaf senescence and plant aging are traits of great interest for breeders Senescing cells undergo important physiological and biochemical changes, while cellular structures such as chloroplasts are degraded with dramatic metabolic consequences for the whole plant The possibility of prolonging the photosynthetic ability of leaves could positively impact the plant's life span with benefits for biomass production and metabolite accumulation; plants with these characteristics display a stay-green phenotype A group of plant transcription factors known as NAC play a pivotal role in controlling senescence: here we describe the involvement of the tomato NAC transcription factor Solyc12g036480, which transcript is present in leaves and floral buds Since its silencing delays leaf senescence and prevents plants from ageing, we renamed Solyc12g0364 HḖBĒ, for the Greek goddess of youth In this manuscript we describe how HEB downregulation negatively affects the progression of senescence, resulting in changes in transcription of senescence-promoting genes, as well as the activity of enzymes involved in chlorophyll degradation, thereby explaining the stay-green phenotype
3 citations
Dissertation•
01 Jan 2017
TL;DR: Experiments revealed that conditions prior to and during the resumption of vegetative growth in the spring could alter the order of emergence of runners and flowers, raising the question of the suitability of F. vesca as a model perennial.
Abstract: The growth and development of Fragaria vesca, as a model plant system, was investigated to better understand the control of perenniality in plants. Experiments revealed that conditions prior to and during the resumption of vegetative growth in the spring could alter the order of emergence of runners and flowers. Under natural conditions, rapid terminal shoot apical meristem growth
occurred during the spring and early summer, followed by a marked decline from June; experimental study suggested this was likely to be a response to runner development.
Environment was found to regulate the fate of axillary buds: low temperature (11°C) and short days (10h) promoted branch crown development, whereas at high temperatures (>18°C) runners were initiated regardless of photoperiod. Autumn conditions induced flowering and F. vesca ecotypes varied in their timing of flower initiation (inferred from emergence); a possible
relationship to latitude was confounded by response variation between years in one ecotype. There was also ecotypic variation in runnering and typically those that flowered earlier runnered less. Detailed experiments on one ecotype showed that spring flower emergence and vegetative growth had a more complex response to winter chilling than that reported for many tree species,
raising the question of the suitability of F. vesca as a model perennial. Greater chill accumulation advanced runner and flower emergence during forcing; the influence of warm periods during chilling was inferred using a range of chill models. Overall, the research highlights the importance of studying plant development in the natural context. An experimental approach is proposed to
allow better understanding of plant ecological development, and suggestions provided for the possible implications of predicted climate change.
3 citations
Cites background from "Epigenetic control of plant senesce..."
...This form of response has been viewed as evidence for a global systemic signal in Arabidopsis, with all shoot meristems responding co-ordinately regardless of the physiological process (Hensel et al., 1994; Ay et al., 2014)....
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01 Jan 2019
TL;DR: In this chapter, the recent progress in leaf senescence research, with special emphasis on the epigenetic regulation via alterations in chromatin organization, is described in detail.
Abstract: The leaf, an important plant organ, plays a significant role in plant development, starting from organogenesis to abscission through senescence. Leaf senescence is the naturally evolved plant aging process, which utilizes the resources from departing leaves to the growing and storage organs of the plant by salvaging nutrients, especially nitrogen, which has a significant role in grain protein reserve. This crucial plant developmental process involves the complex regulatory network of concerted gene activity, hormonal regulation, and many other processes, including biotic and abiotic stresses. Of late, the technological advances in molecular biology make it possible to dissect the underlying complex molecular mechanism involved in leaf senescence. Eukaryotic deoxyribonucleic acid (DNA), along with the basic histone proteins, form three-dimensional (3D) packaging structures called nucleosomes, which can be either the euchromatin or the heterochromatin type, the former being transcriptionally active. A growing body of evidence indicates that the dynamic chromatin structure influences gene expression during senescence and related developmental processes by accessing the euchromatic DNA to transcription factors (TFs), ribonucleic acid (RNA) polymerases, and other regulatory proteins. This transient modification in chromatin architecture during leaf senescence is possible due to histone modification, chromatin remodeling, and changes in methylation, acetylation, phosphorylation, sumoylation, and ubiquitination of the histone proteins. This in turn regulates the transcription of senescence-associated genes (SAGs) in a reversible manner by transcriptional activation or repression during this transition. In this chapter, the recent progress in leaf senescence research, with special emphasis on the epigenetic regulation via alterations in chromatin organization, is described in detail.
3 citations
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TL;DR: The surface of nucleosomes is studded with a multiplicity of modifications that can dictate the higher-order chromatin structure in which DNA is packaged and can orchestrate the ordered recruitment of enzyme complexes to manipulate DNA.
10,046 citations
TL;DR: It is proposed that this epigenetic marking system represents a fundamental regulatory mechanism that has an impact on most, if not all, chromatin-templated processes, with far-reaching consequences for cell fate decisions and both normal and pathological development.
Abstract: Chromatin, the physiological template of all eukaryotic genetic information, is subject to a diverse array of posttranslational modifications that largely impinge on histone amino termini, thereby regulating access to the underlying DNA. Distinct histone amino-terminal modifications can generate synergistic or antagonistic interaction affinities for chromatin-associated proteins, which in turn dictate dynamic transitions between transcriptionally active or transcriptionally silent chromatin states. The combinatorial nature of histone amino-terminal modifications thus reveals a “histone code” that considerably extends the information potential of the genetic code. We propose that this epigenetic marking system represents a fundamental regulatory mechanism that has an impact on most, if not all, chromatin-templated processes, with far-reaching consequences for cell fate decisions and both normal and pathological development.
9,309 citations
TL;DR: The X-ray crystal structure of the nucleosome core particle of chromatin shows in atomic detail how the histone protein octamer is assembled and how 146 base pairs of DNA are organized into a superhelix around it.
Abstract: The X-ray crystal structure of the nucleosome core particle of chromatin shows in atomic detail how the histone protein octamer is assembled and how 146 base pairs of DNA are organized into a superhelix around it. Both histone/histone and histone/DNA interactions depend on the histone fold domains and additional, well ordered structure elements extending from this motif. Histone amino-terminal tails pass over and between the gyres of the DNA superhelix to contact neighbouring particles. The lack of uniformity between multiple histone/DNA-binding sites causes the DNA to deviate from ideal superhelix geometry.
7,841 citations
TL;DR: Drawing on insights from both plants and animals should deepen the understanding of the regulation and biological significance of DNA methylation.
Abstract: Cytosine DNA methylation is a stable epigenetic mark that is crucial for diverse biological processes, including gene and transposon silencing, imprinting and X chromosome inactivation. Recent findings in plants and animals have greatly increased our understanding of the pathways used to accurately target, maintain and modify patterns of DNA methylation and have revealed unanticipated mechanistic similarities between these organisms. Key roles have emerged for small RNAs, proteins with domains that bind methylated DNA and DNA glycosylases in these processes. Drawing on insights from both plants and animals should deepen our understanding of the regulation and biological significance of DNA methylation.
3,180 citations
TL;DR: This work has shown that transcription occurs against a backdrop of mixtures of complex modifications, which probably have several roles, and suggests that a more likely model is of a sophisticated, nuanced chromatin 'language' in which different combinations of basic building blocks yield dynamic functional outcomes.
Abstract: An important development in understanding the influence of chromatin on gene regulation has been the finding that DNA methylation and histone post-translational modifications lead to the recruitment of protein complexes that regulate transcription. Early interpretations of this phenomenon involved gene regulation reflecting predictive activating or repressing types of modification. However, further exploration reveals that transcription occurs against a backdrop of mixtures of complex modifications, which probably have several roles. Although such modifications were initially thought to be a simple code, a more likely model is of a sophisticated, nuanced chromatin 'language' in which different combinations of basic building blocks yield dynamic functional outcomes.
2,674 citations