Cytokinins Promote Rust Susceptibility in Poplar by Suppressing Defence Signalling, Reducing Defence Accumulation and Reprogramming Primary Metabolism.

Elevated cytokinins in poplar during rust infection promote susceptibility by suppressing defenses and increasing nutrient availability, especially with ortho-topolin.

• Why it matters: Understanding how cytokinins influence tree-pathogen interactions is crucial because their roles in woody plants are largely unexplored, limiting potential disease management strategies.
• What they did: Researchers examined cytokinin levels, metabolism, and effects in Populus nigra during infection by Melampsora larici-populina, applying exogenous CKs and analyzing defense responses.
• The result: Findings show that increased CKs weaken chemical defenses and boost free amino acids, facilitating rust colonization, and revealing CKs' role in promoting pathogen susceptibility in trees.