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 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 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 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 Ring/U-Box Protein AtUSR1 Functions in Promoting Leaf Senescence Through JA Signaling Pathway in Arabidopsis

2020 ◽  
Vol 11 ◽  
Author(s):  
Zenglin Zhang ◽  
Mengmeng Xu ◽  
Yongfeng Guo
Keyword(s):  
Transcription Factor ◽  
Signaling Pathway ◽  
Leaf Senescence ◽  
Luciferase Assay ◽  
Significant Delay ◽  
Delayed Senescence ◽  
Age Dependent ◽  
Ja Signaling ◽  
Senescence Phenotype

Leaf senescence is regulated by a large number of internal and environmental factors. Here, we report that AtUSR1 (U-box Senescence Related 1) which encodes a plant Ring/U-box protein, is involved in age-dependent and dark-induced leaf senescence in Arabidopsis. Expression of AtUSR1 gene in leaves was up-regulated in darkness and during aging. Plants of usr1, an AtUSR1 gene knock-down mutant, showed a significant delay in age-dependent and dark-induced leaf senescence and the delayed senescence phenotype was rescued when the AtUSR1 gene was transferred back to the mutant plants. Meanwhile, overexpression of AtUSR1 caused accelerated leaf senescence. Furthermore, the role of AtUSR1 in regulating leaf senescence is related to MYC2-mediuated jasmonic acid (JA) signaling pathway. MeJA treatments promoted the accumulation of AtUSR1 transcripts and this expression activation was dependent on the function of MYC2, a key transcription factor in JA signaling. Dual-luciferase assay results indicated that MYC2 promoted the expression of AtUSR1. Overexpression of AtUSR1 in myc2 mutant plants showed precocious senescence, while myc2 mutation alone caused a delay in leaf senescence, suggesting that AtUSR1 functions downstream to MYC2 in the JA signaling pathway in promoting leaf senescence.

scholarly journals Integrative Analyses of Biochemical Properties and Transcriptome Reveal the Dynamic Changes in Leaf Senescence of Tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Binghui Zhang ◽  
Jiahan Yang ◽  
Gang Gu ◽  
Liao Jin ◽  
Chengliang Chen ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Biochemical Properties ◽  
Dynamic Changes ◽  
Software Analysis ◽  
Nicotiana Tabacum L ◽  
Series Expression ◽  
Functional Investigation ◽  
Short Time

Leaf senescence is an important process of growth and development in plant, and it is a programmed decline controlled by a series of genes. In this study, the biochemical properties and transcriptome at five maturity stages (M1∼M5) of tobacco leaves were analyzed to reveal the dynamic changes in leaf senescence of tobacco. A total of 722, 1,534, 3,723, and 6,933 genes were differentially expressed (DEG) between M1 and M2, M1 and M3, M1 and M4, and M1 and M5, respectively. Significant changes of nitrogen, sugars, and the DEGs related to metabolite accumulation were identified, suggesting the importance of energy metabolism during leaf senescence. Gene Ontology (GO) analysis found that DEGs were enriched in biosynthetic, metabolic, photosynthesis, and redox processes, and especially, the nitrogen metabolic pathways were closely related to the whole leaf senescence process (M1∼M5). All the DEGs were grouped into 12 expression profiles according to their distinct expression patterns based on Short Time-series Expression Miner (STEM) software analysis. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis found that these DEGs were enriched in pathways of carbon metabolism, starch and sucrose metabolism, nitrogen metabolism, and photosynthesis among these expression profiles. A total of 30 core genes were examined by Weight Gene Co-expression Network Analysis (WGCNA), and they appeared to play a crucial role in the regulatory of tobacco senescence. Our results provided valuable information for further functional investigation of leaf senescence in plants.

scholarly journals Exploring gene networks in two sunflower lines with contrasting leaf senescence phenotype using a system biology approach

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Sebastián Moschen ◽  
Johanna Marino ◽  
Salvador Nicosia ◽  
Janet Higgins ◽  
Saleh Alseekh ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Crop Yield ◽  
Leaf Senescence ◽  
Metabolic Pathways ◽  
Gene Networks ◽  
Expression Profiles ◽  
Functional Characterization ◽  
Inbred Lines ◽  
Strong Impact ◽  
The Impact

Abstract Background Leaf senescence is a complex process, controlled by multiple genetic and environmental variables. In sunflower, leaf senescence is triggered abruptly following anthesis thereby limiting the capacity of plants to keep their green leaf area during grain filling, which subsequently has a strong impact on crop yield. Recently, we performed a selection of contrasting sunflower inbred lines for the progress of leaf senescence through a physiological, cytological and molecular approach. Here we present a large scale transcriptomic analysis using RNA-seq and its integration with metabolic profiles for two contrasting sunflower inbred lines, R453 and B481–6 (early and delayed senescence respectively), with the aim of identifying metabolic pathways associated to leaf senescence. Results Gene expression profiles revealed a higher number of differentially expressed genes, as well as, higher expression levels in R453, providing evidence for early activation of the senescence program in this line. Metabolic pathways associated with sugars and nutrient recycling were differentially regulated between the lines. Additionally, we identified transcription factors acting as hubs in the co-expression networks; some previously reported as senescence-associated genes in model species but many are novel candidate genes. Conclusions Understanding the onset and the progress of the senescence process in crops and the identification of these new candidate genes will likely prove highly useful for different management strategies to mitigate the impact of senescence on crop yield. Functional characterization of candidate genes will help to develop molecular tools for biotechnological applications in breeding crop yield.

The functional characterization of LjNRT2.4 indicates a novel, positive role of nitrate for an efficient nodule N 2 ‐fixation activity

2020 ◽  
Vol 228 (2) ◽  
pp. 682-696 ◽  
Author(s):  
Vladimir Totev Valkov ◽  
Stefano Sol ◽  
Alessandra Rogato ◽  
Maurizio Chiurazzi
Keyword(s):  
Functional Characterization ◽  
Positive Role ◽  
Fixation Activity

Are Three Items Sufficient to Measure Sense of Coherence?

2018 ◽  
Vol 34 (4) ◽  
pp. 229-237 ◽  
Author(s):  
Francesca Chiesi ◽  
Andrea Bonacchi ◽  
Caterina Primi ◽  
Alessandro Toccafondi ◽  
Guido Miccinesi
Keyword(s):  
Sense Of Coherence ◽  
Convergent Validity ◽  
Clinical Sample ◽  
Clinical Samples ◽  
Depression Symptoms ◽  
Time Saving ◽  
Positive Role ◽  
Patients With Cancer ◽  
Measure Sense

Abstract. The present study aimed at evaluating if the three-item sense of coherence (SOC) scale developed by Lundberg and Nystrom Peck (1995) can be effectively used for research purpose in both nonclinical and clinical samples. To provide evidence that it represents adequately the measured construct we tested its validity in a nonclinical (N = 658) and clinical sample (N = 764 patients with cancer). Results obtained in the nonclinical sample attested a positive relation of SOC – as measured by the three-item SOC scale – with Antonovsky’s 13-item and 29-item SOC scales (convergent validity), and with dispositional optimism, sense of mastery, anxiety, and depression symptoms (concurrent validity). Results obtained in the clinical sample confirmed the criterion validity of the scale attesting the positive role of SOC – as measured by the three-item SOC scale – on the person’s capacity to respond to illness and treatment. The current study provides evidence that the three-item SOC scale is a valid, low-loading, and time-saving instrument for research purposes on large sample.

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