Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RHO GTPases are regulators of cell polarity and immunity in eukaryotes. In plants, RHO-like RAC/ROP GTPases are regulators of cell shaping, hormone responses, and responses to microbial pathogens. The barley (Hordeum vulgare L.) RAC/ROP protein RACB is required for full susceptibility to penetration by Blumeria graminis f.sp. hordei (Bgh), the barley powdery mildew fungus. Disease susceptibility factors often control host immune responses. Here we show that RACB does not interfere with early microbe-associated molecular pattern-triggered immune responses such as the oxidative burst or activation of mitogen-activated protein kinases. RACB also supports rather than restricts expression of defence-related genes in barley. Instead, silencing of RACB expression by RNAi leads to defects in cell polarity. In particular, initiation and maintenance of root hair growth and development of stomatal subsidiary cells by asymmetric cell division is affected by silencing expression of RACB. Nucleus migration is a common factor of developmental cell polarity and cell-autonomous interaction with Bgh RACB is required for positioning of the nucleus near the site of attack from Bgh We therefore suggest that Bgh profits from RACB's function in cell polarity rather than from immunity-regulating functions of RACB.
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PMID:Barley disease susceptibility factor RACB acts in epidermal cell polarity and positioning of the nucleus. 2705 42

Pathogen-associated molecular pattern-triggered immunity (PTI) builds one of the first layers of plant disease resistance. In susceptible plants, PTI is overcome by adapted pathogens. This can be achieved by suppression of PTI with the help of pathogen virulence effectors. However, effectors may also contribute to modification of host metabolism or cell architecture to ensure successful pathogenesis. Barley responds to treatment with the pathogen-associated molecular patterns flg22 or chitin with phosphorylation of mitogen-activated protein kinases and an oxidative burst. RAC/ROP GTPases can act as positive or negative modulators of these plant immune responses. The RAC/ROP GTPase RACB is a powdery mildew susceptibility factor of barley. However, RACB apparently does not negatively control early PTI responses but functions in polar cell development during invasion of the pathogen into living host epidermal cells. Here, we further discuss the incomplete picture of PTI in Triticeae.
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PMID:PAMP-triggered immune responses in barley and susceptibility to powdery mildew. 2734 36