Evolutionary constraints and regulatory plasticity shape host specialization in the Magnaporthe oryzae species complex.

Genetic differentiation and regulatory plasticity in Magnaporthe oryzae underpin stable host specialization, with only rare shifts like wheat blast occurring over time.

• Why it matters: Understanding the evolutionary mechanisms behind host adaptation is crucial for predicting and controlling pathogen emergence and crop losses, especially as host shifts threaten global food security.
• What they did: The study combines evolutionary genomics, transcriptomics, and metabolomics to propose the "Constrained Plasticity" framework, highlighting three interacting layers—genomic scaffolding, regulatory networks, and metabolic compatibility—that drive host specialization.
• The result: This systems-level model explains the stability of host-adapted lineages and predicts conditions for pathogen emergence, guiding the development of targeted, lineage-aware resistance strategies.