Related Experiment Video

Updated: Jun 2, 2026

Identification of Post-translational Modifications of Plant Protein Complexes
10:07

Identification of Post-translational Modifications of Plant Protein Complexes

Published on: February 22, 2014

Phosphorylation of a WRKY transcription factor by two pathogen-responsive MAPKs drives phytoalexin biosynthesis in

Guohong Mao1, Xiangzong Meng, Yidong Liu

  • 1Department of Biochemistry, Interdisciplinary Plant Group, and Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA.

The Plant Cell
|April 19, 2011
PubMed

Insights

The WRKY33 transcription factor is crucial for plant defense against pathogens. It acts downstream of MPK3/MPK6 kinases to activate camalexin production in Arabidopsis thaliana, enhancing antimicrobial responses.

Area of Science:

  • Plant molecular biology
  • Plant-pathogen interactions
  • Biochemistry

Background:

  • Plants defend against pathogens by producing antimicrobial compounds called phytoalexins.
  • Mitogen-activated protein kinases MPK3 and MPK6 are known to be involved in inducing camalexin, a key phytoalexin in Arabidopsis thaliana.

Purpose of the Study:

  • To identify transcription factors acting downstream of MPK3/MPK6 in the plant immune response.
  • To elucidate the role of WRKY33 in MPK3/MPK6-mediated camalexin biosynthesis.

Main Methods:

  • Analysis of wrky33 mutants for camalexin production.
  • Chromatin immunoprecipitation assays to study WRKY33 promoter binding.
  • Phosphorylation site mutation analysis of WRKY33.
  • Phospho-protein mobility shift assays to detect WRKY33 phosphorylation by MPK3/MPK6.

Main Results:

  • WRKY33 is essential for MPK3/MPK6- and pathogen-induced camalexin production.
  • WRKY33 expression is regulated by the MPK3/MPK6 cascade and WRKY33 binds its own promoter.
  • WRKY33 is phosphorylated by MPK3/MPK6, and this phosphorylation is critical for its function in camalexin biosynthesis.

Conclusions:

  • WRKY33 acts downstream of MPK3/MPK6 in the signaling pathway leading to camalexin production.
  • The MPK3/MPK6-WRKY33 module is a key regulator of metabolic reprogramming for plant defense.
  • This pathway highlights a positive feedback loop involving WRKY33 in plant immunity.

More Related Videos

Pattern-Triggered Oxidative Burst and Seedling Growth Inhibition Assays in Arabidopsis thaliana04:11

Pattern-Triggered Oxidative Burst and Seedling Growth Inhibition Assays in Arabidopsis thaliana

Published on: May 21, 2019

Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem11:50

Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem

Published on: October 1, 2015

Related Concept Videos

Cell Signaling in Plants01:25

Cell Signaling in Plants

Plant cells communicate to coordinate their cycle of growth, flowering and fruiting, and activities in roots, shoots, and leaves in response to the changing environmental conditions. Plant signaling is distinct from animal signaling. Plants primarily utilize enzyme-linked receptors, whereas the largest class of cell-surface receptors in animals are G-protein coupled receptors (GPCRs). Unlike animals, receptor tyrosine kinases are rare in plants. Instead, plants have a diverse class of...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
Gene Regulation During Sporulation01:17

Gene Regulation During Sporulation

Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...