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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Publications at this Location » Publication #381170
Research Project: Biologically Based Technologies for Control of Soil-Borne Pathogens of Vegetables and Ornamentals

Location: Sustainable Agricultural Systems Laboratory

Title: Plant defense against necrotrophic pathogens

Author
item GHOZLAN, MAHMOUD - University Of Nebraska
item EL-ARGAWY, EMAN - University Of Nebraska
item TOKGOZ, SERKAN - University Of Nebraska
item Lakshman, Dilip
item MITRA, AMITAVA - University Of Nebraska

Submitted to: American Journal of Plant Sciences
Publication Type: Review Article
Publication Acceptance Date: 12/26/2020
Publication Date: 12/29/2020
Citation: Ghozlan, M.H., El-Argawy, E., Tokgoz, S., Lakshman, D.K., Mitra, A. 2020. Plant defense against necrotrophic pathogens. American Journal of Plant Sciences. 11(12):2122-2138. https://doi.org/10.4236/ajps.2020.1112149.
DOI: https://doi.org/10.4236/ajps.2020.1112149

Interpretive Summary: Plant parasites may attack and derive nutrition from plants in various modes viz; keeps the host cells alive while constantly deriving nutrition (biotrophic mode), momentarily establishes itself as a biotroph but soon kills the host cell and derives nutrition (hemi-biotrophic mode), or kills the host cell immediately upon establishing infection and derives nutrition from host cells (necrotrophic mode). The latter type association of plants and pathogens is more common amongst several soilborne fungal, bacterial, and oomycetous pathogens. The host plants deploy different defense mechanisms and appropriate immune responses to defend them against these pathogens, such as Pathogen/Microbe Associated Molecular Pattern (P/MAMP) or through Effector Triggered Immunity (ETI). This review summarizes our current understanding of necrotroph-host plant interactions. Progressive knowledge of plant immune response against necrotrophic pathogens may lead to the development of resistant or tolerant crop cultivars.

Technical Abstract: Necrotrophic pathogenic bacteria, fungi and oomycetes are widely distributed and are responsible for significant crop losses. Host plants deploy different defense mechanisms and appropriate immune responses to defend them against these pathogens. Regardless of the pathogen's lifestyle, infection activates plant immune responses either through Pathogen/Microbe Associated Molecular Pattern (P/MAMP) or through Effector Triggered Immunity (ETI). However, as R-genes are not usually associated with resistance to necrotrophs, resistance is largely dependent on the balanced interplay between crucial phytohormones in complex signaling pathways involving jasmonic acid (JA), ethylene, salicylic acid (SA) and abscisic acid (ABA). An increase in salicylic acid levels enhances susceptibility to necrotrophic pathogens but promotes resistance to hemibiotrophs, whereas a deficiency in SA or SA signaling has either no significant impact or affects resistance only at the primary infection site. The same fashion is observed for JA signaling system that appears to elicit resistance against diseases caused by necrotrophic pathogens, and can trigger systemic immunity conferring resistance against them. On the other hand, ABA can play a positive or negative role in plant defense responses to necrotrophs as ABA-mediated defense responses are dependent on specific plant–pathogen interactions. Understanding plant immune response against necrotrophic pathogens may lead to the development of resistant or tolerant crop cultivars.