Different Pathogen Defense Strategies in Arabidopsis: More than Pathogen Recognition

Abstract

Plants constantly suffer from simultaneous infection by multiple pathogens, which can be divided into biotrophic, hemibiotrophic, and necrotrophic pathogens, according to their lifestyles. Many studies have contributed to improving our knowledge of how plants can defend against pathogens, involving different layers of defense mechanisms. In this sense, the review discusses: (1) the functions of PAMP (pathogen-associated molecular pattern)-triggered immunity (PTI) and effector-triggered immunity (ETI), (2) evidence highlighting the functions of salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET)-mediated signaling pathways downstream of PTI and ETI, and (3) other defense aspects, including many novel small molecules that are involved in defense and phenomena, including systemic acquired resistance (SAR) and priming. In particular, we mainly focus on SA and (JA)/ET-mediated signaling pathways. Interactions among them, including synergistic effects and antagonistic effects, are intensively explored. This might be critical to understanding dynamic disease regulation.

A fungal pathogen induces systemic susceptibility and systemic shifts in wheat metabolome and microbiome composition

“…SAR is known to be a central component of the plant immune system [37][38][39] . The spread of immune signals from the site of infection acts to prime systemic plant parts against further pathogen infection.…”

“…8d). Salicylic acid regulates local defense responses against biotrophic pathogens and is a crucial component of SAR in both monocot and dicot plants [37][38][39]41 . The observed increase of salicylate conjugate levels confirms the local and systemic activation of defense responses against a biotrophic pathogen in Chinese Spring.…”

Plant–Pathogen Interactions: Underestimated Roles of Phyto-oxylipins

“…Effectors are recognised and induce a much stronger disease resistance, effector-triggered immunity (ETI). A broad-spectrum resistance called systemic acquired resistance (SAR) is finally activated, which will keep the plant alarmed and prepared for other attacks for weeks to months [44]. SAR can also be activated by elicitors [45][46][47][48].…”

The Pattern and Function of DNA Methylation in Fungal Plant Pathogens

“…Pathogenic fungi utilize diverse strategies to colonize plants and trigger disease [1,[6][7][8]. Some fungi kill their host and feed on dead material (necrotrophs), while others colonize living tissue (biotrophs) [7][8][9][10]. Successful invasion of plant hosts requires tight regulation of pathogenic development and formation of specialized infection structures [7,[11][12][13][14].…”