Plant Pathogenesis-Related Protein Functionality in Disease Resistance

Plants deploy an intricate immune system in which pathogenesis-related (PR) proteins play a central role in restricting pathogen invasion and progression. These proteins encompass diverse enzymatic and non-enzymatic activities, including hydrolytic enzymes that degrade pathogen cell walls, antimicrobial peptides that disrupt microbial membranes, and signalling modulators that amplify defence responses. PR proteins are typically induced by pathogen attack or by the accumulation of specific phytohormones such as salicylic acid, jasmonic acid and ethylene. Their local accumulation at sites of infection contributes to cell-wall reinforcement and direct antagonism of invading pathogens, while systemic induction underpins the phenomenon of acquired resistance throughout the plant. Genetic and biotechnological approaches have demonstrated that overexpression of specific PR proteins, notably β-1,3-glucanases and chitinases, can enhance resistance to a range of fungi and oomycetes without compromising plant fitness. Advances in plastid transformation and precise promoter engineering have enabled high-level, organelle-targeted expression of PR genes, thereby minimising off-target effects and reducing gene flow. Understanding the regulation, subcellular targeting and synergistic action of PR proteins is essential for the development of durable disease-resistant cultivars and for the integration of PR-based strategies into sustainable crop protection programmes.

Research from Nature Portfolio

Recent studies have demonstrated that plastid co-expression of PR proteins can confer robust resistance in field conditions. In tobacco, plastid transformation was used to express polycistronic RNAs encoding a basic PR protein (AP24) together with a β-1,3-glucanase. Transplastomic lines displayed strong resistance to soil-borne and foliar filamentous pathogens, maintaining high levels of both proteins without lesion-mimic symptoms. This work highlights the dual advantages of plastid inheritance—enhanced protein yield and containment of transgenes—while confirming that the concerted action of distinct PR proteins can protect against multiple pathogen classes under high inoculum pressure.

Plant Pathogenesis-Related Protein Functionality in Disease Resistance publication trend

The graph below shows the total number of articles in plant pathogenesis-related protein functionality in disease resistance across all publications each year (not limited to Nature Index journals).

Technical terms

Pathogenesis-related (PR) protein: Inducible plant proteins that contribute to defence by degrading pathogen structures or modulating immune signalling.

β-1,3-glucanase: A hydrolytic enzyme (PR-2 family) that cleaves β-1,3-glucan in fungal cell walls, impairing pathogen integrity.

Chitinase: An enzyme (PR-3 family) that degrades chitin polymers in fungal cell walls, facilitating pathogen lysis.

Plastid transformation: Genetic engineering technique targeting plant chloroplast genomes to achieve high-level, organelle-specific gene expression.

Salicylic acid (SA): A phytohormone that mediates systemic acquired resistance and transcriptional activation of PR genes.

References

1. Expression of pathogenesis-related proteins in transplastomic tobacco plants confers resistance to filamentous pathogens under field trials. Scientific Reports (2019).
2. Effect of Soil and Root Extracts on the Innate Immune Response of American Ginseng (Panax quinquefolius) to Root Rot Caused by Ilyonectria mors-panacis. Plants (2023).
3. Genome-Wide Identification and Expression Analysis of the Pepper β-1,3-gucanase Gene Family in Response to Phytophthora capsici Stresses. Agronomy (2025).
4. Electrical Stimulation Enhances Plant Defense Response in Grapevine through Salicylic Acid-Dependent Defense Pathway. Plants (2021).