MAMP (microbe-associated molecular pattern) triggered immunity in plants

Abstract

Plants are sessile organisms that are under constant attack from microbes. They rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. Preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. The plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting most potentially harmful microbes. The elicitors are essential structures for pathogen survival and are conserved among pathogens. The conserved microbe-specific molecules, referred to as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs), are recognized by the plant innate immune systems pattern recognition receptors (PRRs). General elicitors like flagellin (Flg), elongation factor Tu (EF-Tu), peptidoglycan (PGN), lipopolysaccharides (LPS), Ax21 (Activator of XA21-mediated immunity in rice), fungal chitin, and β-glucans from oomycetes are recognized by plant surface localized PRRs. Several of the MAMPs and their corresponding PRRs have, in recent years, been identified. This review focuses on the current knowledge regarding important MAMPs from bacteria, fungi, and oomycetes, their structure, the plant PRRs that recognizes them, and how they induce MAMP-triggered immunity (MTI) in plants.

TheArabidopsis thalianaTCP transcription factors: A broadening horizon beyond development

“…93 To counteract MTI, evolutionarily diverse microbes independently evolved mechanisms to secrete and deliver effector proteins into the plant extracellular space (apoplastic effectors) or inside the plant cell (cytoplasmic effectors), where pathogen effectors associate with cellular host targets to regulate MTI and/or interfere with metabolism in a fashion conducive to pathogen infection. As a countermeasure, plants recognize specific pathogen effectors via deploying a set of polymorphic intracellular immune receptors, also referred to as disease resistance (R) proteins.…”

Molecular cloning of a coiled-coil-nucleotide-binding-site-leucine-rich repeat gene from pearl millet and its expression pattern in response to the downy mildew pathogen

“…The battle between them activates the basal defense by elicitors such as bacterial flagellins, lipopolysaccharides, peptidoglycan, fungal chitin and β-glucans of oomycetes termed microbe-or pathogenassociated molecular patterns (MAMPs or PAMPs). These in turn are recognized by patternrecognition receptors (PRRs) localized on the membrane leading to pathogen associated molecular pattern triggered immunity (PTI) [1,2,3]. One of the reported MAMP-PRR recognition includes perception of Ax21 a Xanthomonas oryzae pv.…”

The novel elicitor AsES triggers a defense response against Botrytis cinerea in Arabidopsis thaliana

“…The mechanisms evolved by plants to protect themselves from pathogens comprise constitutive barriers and induced defense responses. The cuticle, the cell wall and phytoanticipins are pre-formed physical and chemical barriers that limit access of microbes to the plant cells [1,2]. Numerous pathogens can circumvent the constitutive defenses.…”