scholarly journals The role of sugars in integrating environmental signals during the regulation of leaf senescence

2005 ◽  
Vol 57 (2) ◽  
pp. 391-399 ◽  
Author(s):  
Astrid Wingler ◽  
Sarah Purdy ◽  
Jamie A. MacLean ◽  
Nathalie Pourtau
Keyword(s):  
Leaf Senescence ◽  
Environmental Signals

scholarly journals A WRKY transcription factor, TaWRKY42-B, facilitates initiation of leaf senescence by promoting jasmonic acid biosynthesis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ming-Ming Zhao ◽  
Xiao-Wen Zhang ◽  
Yong-Wei Liu ◽  
Ke Li ◽  
Qi Tan ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Expression Profiles ◽  
Functional Characterization ◽  
Wrky Transcription Factor ◽  
Positive Role ◽  
Environmental Signals ◽  
Source To Sink ◽  
Age Dependent ◽  
Functional Investigation

Abstract Background Leaf senescence comprises numerous cooperative events, integrates environmental signals with age-dependent developmental cues, and coordinates the multifaceted deterioration and source-to-sink allocation of nutrients. In crops, leaf senescence has long been regarded as an essential developmental stage for productivity and quality, whereas functional characterization of candidate genes involved in the regulation of leaf senescence has, thus far, been limited in wheat. Results In this study, we analyzed the expression profiles of 97 WRKY transcription factors (TFs) throughout the progression of leaf senescence in wheat and subsequently isolated a potential regulator of leaf senescence, TaWRKY42-B, for further functional investigation. By phenotypic and physiological analyses in TaWRKY42-B-overexpressing Arabidopsis plants and TaWRKY42-B-silenced wheat plants, we confirmed the positive role of TaWRKY42-B in the initiation of developmental and dark-induced leaf senescence. Furthermore, our results revealed that TaWRKY42-B promotes leaf senescence mainly by interacting with a JA biosynthesis gene, AtLOX3, and its ortholog, TaLOX3, which consequently contributes to the accumulation of JA content. In the present study, we also demonstrated that TaWRKY42-B was functionally conserved with AtWRKY53 in the initiation of age-dependent leaf senescence. Conclusion Our results revealed a novel positive regulator of leaf senescence, TaWRKY42-B, which mediates JA-related leaf senescence via activation of JA biosynthesis and has the potential to be a target gene for molecular breeding in wheat.

scholarly journals Specificity of H2O2 signaling in leaf senescence: is the ratio of H2O2 contents in different cellular compartments sensed in Arabidopsis plants?

2022 ◽  
Vol 27 (1) ◽  
Author(s):  
Ulrike Zentgraf ◽  
Ana Gabriela Andrade-Galan ◽  
Stefan Bieker
Keyword(s):  
Hydrogen Peroxide ◽  
Leaf Senescence ◽  
Mineral Resources ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Differential Impact ◽  
Environmental Signals ◽  
Complex Process ◽  
Cellular Compartments

AbstractLeaf senescence is an integral part of plant development and is driven by endogenous cues such as leaf or plant age. Developmental senescence aims to maximize the usage of carbon, nitrogen and mineral resources for growth and/or for the sake of the next generation. This requires efficient reallocation of the resources out of the senescing tissue into developing parts of the plant such as new leaves, fruits and seeds. However, premature senescence can be induced by severe and long-lasting biotic or abiotic stress conditions. It serves as an exit strategy to guarantee offspring in an unfavorable environment but is often combined with a trade-off in seed number and quality. In order to coordinate the very complex process of developmental senescence with environmental signals, highly organized networks and regulatory cues have to be in place. Reactive oxygen species, especially hydrogen peroxide (H2O2), are involved in senescence as well as in stress signaling. Here, we want to summarize the role of H2O2 as a signaling molecule in leaf senescence and shed more light on how specificity in signaling might be achieved. Altered hydrogen peroxide contents in specific compartments revealed a differential impact of H2O2 produced in different compartments. Arabidopsis lines with lower H2O2 levels in chloroplasts and cytoplasm point to the possibility that not the actual contents but the ratio between the two different compartments is sensed by the plant cells.

scholarly journals The Role of Light and Circadian Clock in Regulation of Leaf Senescence

2021 ◽  
Vol 12 ◽  
Author(s):  
Juhyeon Lee ◽  
Myeong Hoon Kang ◽  
Jung Yeon Kim ◽  
Pyung Ok Lim
Keyword(s):  
Circadian Clock ◽  
Leaf Senescence ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Control Plant ◽  
Structural Features ◽  
Clock Period ◽  
Environmental Signals

Leaf senescence is an integrated response of the cells to develop age information and various environmental signals. Thus, some of the genes involved in the response to environmental changes are expected to regulate leaf senescence. Light acts not only as the primary source of energy for photosynthesis but also as an essential environmental cue that directly control plant growth and development including leaf senescence. The molecular mechanisms linking light signaling to leaf senescence have recently emerged, exploring the role of Phytochrome-Interacting Factors (PIFs) as a central player leading to diverse senescence responses, senescence-promoting gene regulatory networks (GRNs) involving PIFs, and structural features of transcription modules in GRNs. The circadian clock is an endogenous time-keeping system for the adaptation of organisms to changing environmental signals and coordinates developmental events throughout the life of the plant. Circadian rhythms can be reset by environmental signals, such as light-dark or temperature cycles, to match the environmental cycle. Research advances have led to the discovery of the role of core clock components as senescence regulators and their underlying signaling pathways, as well as the age-dependent shortening of the circadian clock period. These discoveries highlight the close relationship between the circadian system and leaf senescence. Key issues remain to be elucidated, including the effect of light on leaf senescence in relation to the circadian clock, and the identification of key molecules linking aging, light, and the circadian clock, and integration mechanisms of various senescence-affecting signals at the multi-regulation levels in dynamics point of view.

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

scholarly journals Programmed chloroplast destruction during leaf senescence involves 13-lipoxygenase (13-LOX)

2016 ◽  
Vol 113 (12) ◽  
pp. 3383-3388 ◽  
Author(s):  
Armin Springer ◽  
ChulHee Kang ◽  
Sachin Rustgi ◽  
Diter von Wettstein ◽  
Christiane Reinbothe ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Critical Role ◽  
Transit Peptide ◽  
Physiological Changes ◽  
Pathogen Defense ◽  
Chloroplast Transit Peptide ◽  
Selective Destruction ◽  
Plastid Envelope ◽  
Volatile Aldehydes

Leaf senescence is the terminal stage in the development of perennial plants. Massive physiological changes occur that lead to the shut down of photosynthesis and a cessation of growth. Leaf senescence involves the selective destruction of the chloroplast as the site of photosynthesis. Here, we show that 13-lipoxygenase (13-LOX) accomplishes a key role in the destruction of chloroplasts in senescing plants and propose a critical role of its NH2-terminal chloroplast transit peptide. The 13-LOX enzyme identified here accumulated in the plastid envelope and catalyzed the dioxygenation of unsaturated membrane fatty acids, leading to a selective destruction of the chloroplast and the release of stromal constituents. Because 13-LOX pathway products comprise compounds involved in insect deterrence and pathogen defense (volatile aldehydes and oxylipins), a mechanism of unmolested nitrogen and carbon relocation is suggested that occurs from leaves to seeds and roots during fall.

Role of Histones During Leaf Senescence

2019 ◽  
pp. 187-197 ◽  
Author(s):  
Bhubaneswar Pradhan ◽  
Krishna Kumar Jangid ◽  
Maryam Sarwat ◽  
Sujit Kumar Bishi
Keyword(s):  
Leaf Senescence

scholarly journals Endospores and other lysis-resistant bacteria comprise a widely shared core community within the human microbiota

2017 ◽  
Author(s):  
Sean M. Kearney ◽  
Sean M. Gibbons ◽  
Mathilde Poyet ◽  
Thomas Gurry ◽  
Kevin Bullock ◽  
...  
Keyword(s):  
Dietary Fatty Acids ◽  
Resistant Bacteria ◽  
Human Gut ◽  
Environmental Signals ◽  
Human Microbiota ◽  
Disease States ◽  
Culture Independent ◽  
Health And Disease ◽  
Over Time

AbstractEndospore-formers in the human microbiota are well adapted for host-to-host transmission, and an emerging consensus points to their role in determining health and disease states in the gut. The human gut, more than any other environment, encourages the maintenance of endospore formation, with recent culture-based work suggesting that over 50% of genera in the microbiome carry genes attributed to this trait. However, there has been limited work on the ecological role of endospores and other stress-resistant cellular states in the human gut. In fact, there is no data to indicate whether organisms with the genetic potential to form endospores actually form endosporesin situand how sporulation varies across individuals and over time. Here, we applied a culture-independent protocol to enrich for endospores and other stress-resistant cells in human feces to identify variation in these states across people and within an individual over time. We see that cells with resistant states are more likely than those without to be shared among multiple individuals, which suggests that these resistant states are particularly adapted for cross-host dissemination. Furthermore, we use untargeted fecal metabolomics in 24 individuals and within a person over time to show that these organisms respond to shared environmental signals, and in particular, dietary fatty acids, that likely mediate colonization of recently disturbed human guts.

scholarly journals SAUR49 Can Positively Regulate Leaf Senescence by Suppressing SSPP in Arabidopsis

2019 ◽  
Vol 61 (3) ◽  
pp. 644-658 ◽  
Author(s):  
Zewen Wen ◽  
Yuanyuan Mei ◽  
Jie Zhou ◽  
Yanjiao Cui ◽  
Dan Wang ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Protein Phosphatase ◽  
Functional Characterization ◽  
Transcript Level ◽  
In Planta ◽  
Environmental Signals ◽  
Receptor Like Kinase ◽  
Premature Leaf Senescence ◽  
Natural Leaf ◽  
Two Hybrid

Abstract The involvement of SMALL AUXIN-UP RNA (SAUR) proteins in leaf senescence has been more and more acknowledged, but the detailed mechanisms remain unclear. In the present study, we performed yeast two-hybrid assays and identified SAUR49 as an interactor of SENESCENCE SUPPRESSED PROTEIN PHOSPHATASE (SSPP), which is a PP2C protein phosphatase that negatively regulates Arabidopsis leaf senescence by suppressing the leucine-rich repeat receptor-like protein kinase SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE (SARK), as reported previously by our group. The interaction between SAUR49 and SSPP was further confirmed in planta. Functional characterization revealed that SAUR49 is a positive regulator of leaf senescence. The accumulation level of SAUR49 protein increased during natural leaf senescence in Arabidopsis. The transcript level of SAUR49 was upregulated during SARK-induced premature leaf senescence but downregulated during SSPP-mediated delayed leaf senescence. Overexpression of SAUR49 significantly accelerated both natural and dark-induced leaf senescence in Arabidopsis. More importantly, SAUR49 overexpression completely reversed SSPP-induced delayed leaf senescence. In addition, overexpression of SAUR49 reversed the decreased plasma membrane H+-ATPase activity mediated by SSPP. Taken together, the results showed that SAUR49 functions in accelerating the leaf senescence process via the activation of SARK-mediated leaf senescence signaling by suppressing SSPP. We further identified four other SSPP-interacting SAURs, SAUR30, SAUR39, SAUR41 and SAUR72, that may act redundantly with SAUR49 in regulating leaf senescence. All these observations indicated that certain members of the SAUR family may serve as an important hub that integrates various hormonal and environmental signals with senescence signals in Arabidopsis.

scholarly journals Protein Phosphatases in G1 Regulation

2020 ◽  
Vol 21 (2) ◽  
pp. 395 ◽  
Author(s):  
Ruth Martín ◽  
Vilte Stonyte ◽  
Sandra Lopez-Aviles
Keyword(s):  
Cell Cycle ◽  
Protein Phosphatases ◽  
Eukaryotic Cells ◽  
Signalling Pathways ◽  
Cyclin Dependent Kinase ◽  
Restriction Point ◽  
Environmental Signals ◽  
Substrate Phosphorylation ◽  
Cell Cycle Machinery

Eukaryotic cells make the decision to proliferate, to differentiate or to cease dividing during G1, before passage through the restriction point or Start. Keeping cyclin-dependent kinase (CDK) activity low during this period restricts commitment to a new cell cycle and is essential to provide the adequate timeframe for the sensing of environmental signals. Here, we review the role of protein phosphatases in the modulation of CDK activity and as the counteracting force for CDK-dependent substrate phosphorylation, in budding and fission yeast. Moreover, we discuss recent findings that place protein phosphatases in the interface between nutritional signalling pathways and the cell cycle machinery.

Sign in / Sign up

Export Citation Format

Share Document