The plant Mediator complex and its role in jasmonate signaling

Abstract The Mediator complex is an essential, multisubunit transcriptional coactivator that is highly conserved in eukaryotes. Mediator interacts with gene-specific transcription factors, the RNA polymerase II transcriptional machinery, as well as several other factors involved in transcription, and acts as an integral hub to regulate various aspects of transcription. Recent studies of the plant Mediator complex have established that it functions in diverse aspects of plant development and fitness. Jasmonate (JA) is an oxylipin-derived plant hormone that regulates plant immunity and development. The basic helix–loop–helix transcription factor MYC2, which is a master regulator of JA signaling, orchestrates genome-wide transcriptional reprogramming of plant cells to coordinate defense- and growth-related processes. Here, we review the function of the plant Mediator complex in regulating JA signaling. We focus on the multifunctional Mediator subunit MED25, which emerges as an integrative hub for the transcriptional regulation of jasmonate signaling.

Download Full-text

Genome-Wide Analysis Reveals the Role of Mediator Complex in the Soybean—Phytophthora sojae Interaction

International Journal of Molecular Sciences ◽

10.3390/ijms20184570 ◽

2019 ◽

Vol 20 (18) ◽

pp. 4570 ◽

Cited By ~ 1

Author(s):

Dong Xue ◽

Na Guo ◽

Xiao-Li Zhang ◽

Jin-Ming Zhao ◽

Yuan-Peng Bu ◽

...

Keyword(s):

Salicylic Acid ◽

Rna Polymerase Ii ◽

Phytophthora Sojae ◽

Mediator Complex ◽

Limited Information ◽

Empty Vector ◽

Genome Wide ◽

Root Transformation ◽

Duplication Events

The mediator complex is an essential link between transcription factors and RNA polymerase II, and mainly functions in the transduction of diverse signals to genes involved in different pathways. Limited information is available on the role of soybean mediator subunits in growth and development, and their participation in defense response regulation. Here, we performed genome-wide identification of the 95 soybean mediator subunits, which were unevenly localized on the 20 chromosomes and only segmental duplication events were detected. We focused on GmMED16-1, which is highly expressed in the roots, for further functional analysis. Transcription of GmMED16-1 was induced in response to Phytophthora sojae infection. Agrobacterium rhizogenes mediated soybean hairy root transformation was performed for the silencing of the GmMED16-1 gene. Silencing of GmMED16-1 led to an enhanced susceptibility phenotype and increased accumulation of P. sojae biomass in hairy roots of transformants. The transcript levels of NPR1, PR1a, and PR5 in the salicylic acid defense pathway in roots of GmMED16-1-silenced transformants were lower than those of empty-vector transformants. The results provide evidence that GmMED16-1 may participate in the soybean–P. sojae interaction via a salicylic acid-dependent process.

Download Full-text

Role of the pre-initiation complex in Mediator recruitment and dynamics

eLife ◽

10.7554/elife.39633 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 10

Author(s):

Elisabeth R Knoll ◽

Z Iris Zhu ◽

Debasish Sarkar ◽

David Landsman ◽

Randall H Morse

Keyword(s):

Rna Polymerase Ii ◽

Gene Activation ◽

Mediator Complex ◽

Gene Promoters ◽

Initiation Complex ◽

Yeast Saccharomyces Cerevisiae ◽

Pol Ii ◽

Genome Wide ◽

Cooperative Assembly

The Mediator complex stimulates the cooperative assembly of a pre-initiation complex (PIC) and recruitment of RNA Polymerase II (Pol II) for gene activation. The core Mediator complex is organized into head, middle, and tail modules, and in budding yeast (Saccharomyces cerevisiae), Mediator recruitment has generally been ascribed to sequence-specific activators engaging the tail module triad of Med2-Med3-Med15 at upstream activating sequences (UASs). We show that yeast lacking Med2-Med3-Med15 are viable and that Mediator and PolII are recruited to promoters genome-wide in these cells, albeit at reduced levels. To test whether Mediator might alternatively be recruited via interactions with the PIC, we examined Mediator association genome-wide after depleting PIC components. We found that depletion of Taf1, Rpb3, and TBP profoundly affected Mediator association at active gene promoters, with TBP being critical for transit of Mediator from UAS to promoter, while Pol II and Taf1 stabilize Mediator association at proximal promoters.

Download Full-text

Role of the pre-initiation complex in Mediator recruitment and dynamics

10.1101/207282 ◽

2017 ◽

Cited By ~ 1

Author(s):

Elisabeth R. Knoll ◽

Z. Iris Zhu ◽

David Landsman ◽

Randall H. Morse

Keyword(s):

Rna Polymerase Ii ◽

Gene Activation ◽

Mediator Complex ◽

Gene Promoters ◽

Initiation Complex ◽

Eukaryotic Transcription ◽

Pol Ii ◽

Genome Wide ◽

Complex Functions

AbstractThe Mediator complex functions in eukaryotic transcription by stimulating the cooperative assembly of a pre-initiation complex (PIC) and recruitment of RNA Polymerase II (Pol II) for gene activation. The core Mediator complex is organized into head, middle, and tail modules, and in budding yeast (Saccharomyces cerevisiae), Mediator recruitment has generally been ascribed to sequence-specific activators engaging the tail module triad of Med2-Med3-Med15 at upstream activating sequences (UASs). We show that med2Δ med3Δ med15Δ yeast are viable and that Mediator lacking Med2-Med3-Med15 is associated with active promoters genome-wide. To test whether Mediator might alternatively be recruited via interactions with the PIC, we examined Mediator association genome-wide after depleting PIC components. We found that depletion of Taf1, Rpb3, and TBP profoundly affected Mediator association at active gene promoters, with TBP being critical for transit of Mediator from UAS to promoter, while Pol II and Taf1 stabilize Mediator association at proximal promoters.

Download Full-text

Faculty Opinions recommendation of Genome-wide analyses reveal RNA polymerase II located upstream of genes poised for rapid response upon S. cerevisiae stationary phase exit.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1025401.300733 ◽

2005 ◽

Author(s):

Michael Meisterernst

Keyword(s):

Rna Polymerase ◽

Stationary Phase ◽

Rna Polymerase Ii ◽

Rapid Response ◽

Genome Wide

Download Full-text

Genome-Wide Characterization of Jasmonates Signaling Components Reveals the Essential Role of ZmCOI1a-ZmJAZ15 Action Module in Regulating Maize Immunity to Gibberella Stalk Rot

International Journal of Molecular Sciences ◽

10.3390/ijms22020870 ◽

2021 ◽

Vol 22 (2) ◽

pp. 870

Author(s):

Liang Ma ◽

Yali Sun ◽

Xinsen Ruan ◽

Pei-Cheng Huang ◽

Shi Wang ◽

...

Keyword(s):

Fusarium Graminearum ◽

Maize Production ◽

Stalk Rot ◽

Enhanced Resistance ◽

Genome Wide ◽

Susceptibility Factors ◽

A Genome ◽

Function Module ◽

Ja Signaling ◽

Signaling Components

Gibberella stalk rot (GSR) by Fusarium graminearum causes significant losses of maize production worldwide. Jasmonates (JAs) have been broadly known in regulating defense against pathogens through the homeostasis of active JAs and COI-JAZ-MYC function module. However, the functions of different molecular species of JAs and COI-JAZ-MYC module in maize interactions with Fusarium graminearum and regulation of diverse metabolites remain unknown. In this study, we found that exogenous application of MeJA strongly enhanced resistance to GSR. RNA-seq analysis showed that MeJA activated multiple genes in JA pathways, which prompted us to perform a genome-wide screening of key JA signaling components in maize. Yeast Two-Hybrid, Split-Luciferase, and Pull-down assays revealed that the JA functional and structural mimic coronatine (COR) functions as an essential ligand to trigger the interaction between ZmCOIa and ZmJAZ15. By deploying CRISPR-cas9 knockout and Mutator insertional mutants, we demonstrated that coi1a mutant is more resistant, whereas jaz15 mutant is more susceptible to GSR. Moreover, JA-deficient opr7-5opr8-2 mutant displayed enhanced resistance to GSR compared to wild type. Together, these results provide strong evidence that ZmJAZ15 plays a pivotal role, whereas ZmCOIa and endogenous JA itself might function as susceptibility factors, in maize immunity to GSR.

Download Full-text