Knowing me, knowing you: Self and non-self recognition in plant immunity

Abstract

Perception of non-self molecules known as microbe-associated molecular patterns (MAMPs) by host pattern recognition receptors (PRRs) activates plant pattern-triggered immunity (PTI). Pathogen infections often trigger the release of modified-self molecules, termed damage- or danger-associated molecular patterns (DAMPs), which modulate MAMP-triggered signaling to shape the frontline of plant immune responses against infections. In the context of advances in identifying MAMPs and DAMPs, cognate receptors, and their signaling, here, we focus on the most recent breakthroughs in understanding the perception and role of non-self and modified-self patterns. We highlight the commonalities and differences of MAMPs from diverse microbes, insects, and parasitic plants, as well as the production and perception of DAMPs upon infections. We discuss the interplay between MAMPs and DAMPs for emerging themes of the mutual potentiation and attenuation of PTI signaling upon MAMP and DAMP perception during infections.

Citrus genomic resources unravel putative genetic determinants of Huanglongbing pathogenicity

“…Bacterial pathogens trigger immune response via recognition by either membrane-localized pattern recognition receptors (PRRs) and intracellular nucleotide-binding domain leucine-rich repeat receptors (NLRs), 12 , 13 leading to PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI), respectively. PTI and ETI share multiple downstream immune responses including the influx of Ca 2+ , ROS burst, activation of mitogen-activated protein kinase (MAPK) cascades, defense gene induction, and biosynthesis of defense phytohormones.…”

“…PTI and ETI share multiple downstream immune responses including the influx of Ca 2+ , ROS burst, activation of mitogen-activated protein kinase (MAPK) cascades, defense gene induction, and biosynthesis of defense phytohormones. 12 , 13 Recent studies showed that both PTI and ETI are needed to mount a robust immune response, as they synergistically enhance each other. 14 , 15 , 16 , 17 , 18 , 19 , 20 In citrus there are a large number of genes involved in these two signaling pathways.…”

Protein Profiling of Psittacanthus calyculatus during Mesquite Infection

“…Diverse parasitic hormones have been anticipated in the site of infection from gene expression analysis related to accumulation of auxins in the early stages of the haustorium development [ 36 , 37 , 38 , 39 , 40 ]. Nevertheless, successful infection of P. calyculatus in a host tree is dependent on the establishment mechanisms in phenological stages such as germination and growth of seedlings, as well as metabolic signatures in haustorium development, enzymes involved in bark layer degradation and xylem connection, and molecular and genetic factors that inhibit the host immune system [ 34 , 41 , 42 , 43 , 44 , 45 , 46 ]. Therefore, molecular analyses on the development of the haustorium are necessary, involving scanning biomolecules such as phytohormones, proteins, and enzymes involved in haustorium development and thus in the establishment on the host.…”

Natural variation of immune epitopes reveals intrabacterial antagonism

“…1,2,3 Surface-localized pattern recognition receptors (PRRs) include receptor-like kinases (RLKs) and receptor-like proteins (RLPs) that recognize conserved MAMPs or damage-associated molecular patterns, resulting in PRRtriggered immunity (PTI). 3,4 Activation of PTI induces multiple defense responses including: the production of reactive oxygen species (ROS), ethylene production, apoplast alkalization, activation of mitogen-activated protein kinase (MAPK) cascades, transcriptional reprogramming, and callose deposition at the cell wall culminating in disease resistance. 4,5 The most well-studied PRR is FLAGELLIN-SENSING 2 (FLS2), which recognizes the 22-amino acid flagellin epitope, flg22, from bacterial FliC.…”