cellular-immunity
Cellular immunity refers to immune responses driven by the activation of specialized cells rather than antibody production, encompassing processes like pathogen recognition, signaling cascades, and targeted cellular responses. While classically described in animals, analogous cell-mediated defense mechanisms in plants involve the activation of immune signaling pathways, programmed cell death, and the release of defense compounds in response to pathogens. Understanding these cellular-level immune processes helps researchers decode how plants recognize and resist disease, informing the development of more resilient crops.
open_in_new WikipediaPubMed · 2026-04-11
Plants have an internal quality-control system in a cellular compartment called the endoplasmic reticulum that, when stressed by pathogens, triggers immune defenses. This review maps how that stress response links to plant immunity—and how bacteria, fungi, and viruses have evolved tricks to shut it down.
The unfolded protein response (UPR) integrates with at least three distinct layers of plant immunity—pattern-triggered immunity, effector-triggered immunity, and systemic defenses—making it a central immune hub rather than a peripheral stress response.
Two major plant hormones, salicylic acid and jasmonic acid, act as 'rheostats' that fine-tune the balance between ER stress signaling and immune activation, determining whether a plant resists or succumbs to infection.
Pathogens including bacteria, oomycetes, and viruses deploy specific virulence factors that directly target the sensors and transcription factors of the UPR, actively dampening this immune pathway to gain a foothold in the plant.