scholarly journals A Tripartite Amplification Loop Involving the Transcription Factor WRKY75, Salicylic Acid, and Reactive Oxygen Species Accelerates Leaf Senescence

2017 ◽  
Vol 29 (11) ◽  
pp. 2854-2870 ◽  
Author(s):  
Pengru Guo ◽  
Zhonghai Li ◽  
Peixin Huang ◽  
Bosheng Li ◽  
Shuang Fang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Transcription Factor ◽  
Salicylic Acid ◽  
Leaf Senescence ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Amplification Loop

scholarly journals WRKY55 transcription factor positively regulates leaf senescence and the defense response by modulating the transcription of genes implicated in the biosynthesis of reactive oxygen species and salicylic acid in Arabidopsis

Development ◽  
2020 ◽  
Vol 147 (16) ◽  
pp. dev189647
Author(s):  
Yiqiao Wang ◽  
Xing Cui ◽  
Bo Yang ◽  
Shutao Xu ◽  
Xiangyan Wei ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Transcription Factor ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Leaf Senescence ◽  
Single Gene ◽  
Bacterial Pathogen ◽  
Reactive Oxygen ◽  
Pathogen Resistance ◽  
Oxygen Species

ABSTRACTReactive oxygen species (ROS) and salicylic acid (SA) are two factors regulating leaf senescence and defense against pathogens. However, how a single gene integrates both ROS and SA pathways remains poorly understood. Here, we show that Arabidopsis WRKY55 transcription factor positively regulates ROS and SA accumulation, and thus leaf senescence and resistance against the bacterial pathogen Pseudomonas syringae. WRKY55 is predominantly expressed in senescent leaves and encodes a transcriptional activator localized to nuclei. Both inducible and constitutive overexpression of WRKY55 accelerates leaf senescence, whereas mutants delay it. Transcriptomic sequencing identified 1448 differentially expressed genes, of which 1157 genes are upregulated by WRKY55 expression. Accordingly, the ROS and SA contents in WRKY55-overexpressing plants are higher than those in control plants, whereas the opposite occurs in mutants. Moreover, WRKY55 positively regulates defense against P. syringae. Finally, we show that WRKY55 activates the expression of RbohD, ICS1, PBS3 and SAG13 by binding directly to the W-box-containing fragments. Taken together, our work has identified a new WRKY transcription factor that integrates both ROS and SA pathways to regulate leaf senescence and pathogen resistance.

scholarly journals Transcription Factor NAC075 Delays Leaf Senescence by Deterring Reactive Oxygen Species Accumulation in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Chengcheng Kan ◽  
Yi Zhang ◽  
Hou-Ling Wang ◽  
Yingbai Shen ◽  
Xinli Xia ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Transcription Factor ◽  
Leaf Senescence ◽  
Critical Role ◽  
Reactive Oxygen ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Loss Of Function ◽  
Mobility Shift

Leaf senescence is a highly complex genetic process that is finely tuned by multiple layers of regulation. Among them, transcriptional regulation plays a critical role in controlling the initiation and progression of leaf senescence. Here, we found that the NAC transcription factor NAC075 functions as a novel negative regulator of leaf senescence. Loss of function of NAC075 promotes leaf senescence in an age-dependent manner, whereas constitutive overexpression of NAC075 delays senescence in Arabidopsis. Transcriptome analysis revealed that transcript levels of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) are significantly suppressed in nac075 mutants compared with wild-type plants. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) analyses revealed that NAC075 directly binds the promoter of catalase 2 (CAT2). Moreover, genetic analysis showed that overexpression of CAT2 suppresses the overproduction of reactive oxygen species (ROS) and the early senescence phenotypes of nac075 mutants, suggesting that CAT2 acts downstream of NAC075 to delay leaf senescence by repressing ROS accumulation. Collectively, our findings provide a new regulatory module involving NAC075-CAT2-ROS in controlling leaf senescence in Arabidopsis.

scholarly journals The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species

2018 ◽  
Vol 19 (9) ◽  
pp. 2600 ◽  
Author(s):  
Rebecca Pratt ◽  
Cameron Brickman ◽  
Cameron Cottrill ◽  
Joseph Shapiro ◽  
Jiang Liu
Keyword(s):  
Reactive Oxygen Species ◽  
Positive Feedback ◽  
Reactive Oxygen ◽  
Underlying Mechanism ◽  
Short Review ◽  
Oxygen Species ◽  
Signaling Function ◽  
Amplification Loop

The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.

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