Plant-Pathogen Interaction Mechanisms in Populus Species

Populus species occupy a central role in forest ecosystems and bioenergy plantations, yet their long lifespan renders them vulnerable to a broad spectrum of pathogens. Defence against invading fungi and bacteria is initiated by cell-surface receptors that detect conserved microbial features, leading to pattern-triggered immunity. Successful pathogens then deploy effectors that can subvert these basal defences, but resistance (R) proteins often recognise such effectors and trigger a stronger, effector-triggered immunity. Downstream of these recognition events, complex signalling networks involving salicylic acid, jasmonic acid and abscisic acid orchestrate transcriptional reprogramming of defence genes. Key transcription factors, including members of the WRKY, NAC and MYB families, activate pathways for cell-wall reinforcement, phenylpropanoid biosynthesis and accumulation of antifungal metabolites such as flavan-3-ols. Recent work has also highlighted the role of small RNAs in interkingdom communication, whereby poplar-derived siRNAs target pathogen genes and contribute to co-evolutionary dynamics. In parallel, pathogen infection can disrupt host carbon metabolism and transport, tipping the balance between growth and defence. Advances in genomic and transcriptomic tools have elucidated the temporal coordination of gene networks, from early recognition to late-stage cell death, offering new strategies for breeding disease-resistant cultivars and sustainable forest management.

Research from Nature Portfolio

Recent studies have shown that canker-causing fungi such as Botryosphaeria and Valsa induce a form of carbon starvation in poplar stems by downregulating genes involved in carbon metabolism and transport. Early transcriptome profiling revealed a marked decrease in expression of sugar-transporters and enzymes of starch and sucrose metabolism, while genes for secondary metabolite production and lignin synthesis were upregulated as a defensive response. Physiological measurements confirmed a progressive decline in photosynthetic assimilation and non-structural carbohydrate reserves, accompanied by increased water-use efficiency. These findings illuminate a chronological sequence in which molecular inhibition of carbon pathways precedes depletion of energy stores, suggesting that reinforcing carbon allocation mechanisms could enhance poplar resilience to canker diseases.

Plant-Pathogen Interaction Mechanisms in Populus Species publication trend

The graph below shows the total number of articles in plant-pathogen interaction mechanisms in populus species across all publications each year (not limited to Nature Index journals).

Technical terms

Pattern-triggered immunity (PTI): A basal defence response activated when cell-surface receptors recognise conserved microbial molecules.

Effector-triggered immunity (ETI): A robust immune reaction initiated by intracellular resistance proteins upon detection of pathogen effectors.

Nucleotide-binding leucine-rich repeat (NB-LRR) proteins: Intracellular receptors that detect pathogen effectors and activate ETI.

Phenylpropanoid pathway: A metabolic route producing lignin, flavonoids and other defence compounds.

Weighted gene co-expression network analysis (WGCNA): A computational method for identifying clusters of co-expressed genes associated with specific traits.

Small interfering RNA (siRNA): Short RNA molecules that guide sequence-specific degradation of complementary mRNA, including those of pathogens.

References

1. Transcriptome Sequencing and WGCNA Reveal Key Genes in Response to Leaf Blight in Poplar. International Journal of Molecular Sciences (2023).
2. The responses of poplars to fungal pathogens: A review of the defensive pathway. Frontiers in Plant Science (2023).
3. Salicylic acid activates poplar defense against the biotrophic rust fungus Melampsora larici‐populina via increased biosynthesis of catechin and proanthocyanidins. New Phytologist (2018).
4. Fungal canker pathogens trigger carbon starvation by inhibiting carbon metabolism in poplar stems. Scientific Reports (2019).