scholarly journals The Arabidopsis Mediator complex subunits MED14/SWP and MED16/SFR6/IEN1 differentially regulate defense gene expression in plant immune responses

2013 ◽  
Vol 75 (3) ◽  
pp. 484-497 ◽  
Author(s):  
Xudong Zhang ◽  
Jin Yao ◽  
Yanping Zhang ◽  
Yijun Sun ◽  
Zhonglin Mou
Keyword(s):  
Gene Expression ◽  
Immune Responses ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
Defense Gene

scholarly journals The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

2021 ◽  
Author(s):  
Huaming He ◽  
Jordi Denecker ◽  
Katrien Van Der Kelen ◽  
Patrick Willems ◽  
Robin Pottie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Negative Regulator ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
A Genome ◽  
Oxidative Stress Responses

Abstract Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.

scholarly journals HOS15 is a transcriptional corepressor of NPR1-mediated gene activation of plant immunity

2020 ◽  
Vol 117 (48) ◽  
pp. 30805-30815
Author(s):  
Mingzhe Shen ◽  
Chae Jin Lim ◽  
Junghoon Park ◽  
Jeong Eun Kim ◽  
Dongwon Baek ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ubiquitin Ligase ◽  
Transcriptional Activation ◽  
Plant Immunity ◽  
Gene Activation ◽  
Transcriptional Corepressor ◽  
Defense Gene Expression ◽  
Dynamic Regulation ◽  
Defense Gene ◽  
Transcriptional Corepressors

Transcriptional regulation is a complex and pivotal process in living cells. HOS15 is a transcriptional corepressor. Although transcriptional repressors generally have been associated with inactive genes, increasing evidence indicates that, through poorly understood mechanisms, transcriptional corepressors also associate with actively transcribed genes. Here, we show that HOS15 is the substrate receptor for an SCF/CUL1 E3 ubiquitin ligase complex (SCFHOS15) that negatively regulates plant immunity by destabilizing transcriptional activation complexes containing NPR1 and associated transcriptional activators. In unchallenged conditions, HOS15 continuously eliminates NPR1 to prevent inappropriate defense gene expression. Upon defense activation, HOS15 preferentially associates with phosphorylated NPR1 to stimulate rapid degradation of transcriptionally active NPR1 and thus limit the extent of defense gene expression. Our findings indicate that HOS15-mediated ubiquitination and elimination of NPR1 produce effects contrary to those of CUL3-containing ubiquitin ligase that coactivate defense gene expression. Thus, HOS15 plays a key role in the dynamic regulation of pre- and postactivation host defense.

scholarly journals Characterization of a Diffusible Signal Capable of Inducing Defense Gene Expression in Tobacco

1997 ◽  
Vol 113 (2) ◽  
pp. 621-629 ◽  
Author(s):  
J. Chappell ◽  
A. Levine ◽  
R. Tenhaken ◽  
M. Lusso ◽  
C. Lamb
Keyword(s):  
Gene Expression ◽  
Defense Gene Expression ◽  
Defense Gene

Decreased defense gene expression in tolerance versus resistance to Verticillium dahliae in potato

2013 ◽  
Vol 13 (3) ◽  
pp. 367-378 ◽  
Author(s):  
Helen H. Tai ◽  
Claudia Goyer ◽  
H. W. (Bud) Platt ◽  
David De Koeyer ◽  
Agnes Murphy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Verticillium Dahliae ◽  
Defense Gene Expression ◽  
Defense Gene
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