Phylogenetic analysis reveals contrasting levels of host specialization in Rhizoctonia solani, highlighting evolutionary drivers of fungal pathogen population structure.
Key Points
To evaluate global patterns of genetic diversity, phylogenetic structure, and host-transition dynamics across anastomosis groups of the plant pathogen Rhizoctonia solani.
Analyzed a global dataset of 4,119 R. solani rDNA-ITS sequences collected over 70 years, including newly sampled isolates from Nebraska.
Evaluated phylogenetic consistency across markers using a concatenated ITS and TEF-1α dataset of 162 sequences.
Reconstructed ancestral host states and inferred transition dynamics across plant families.
Phylogenetic analysis confirmed that most recognized anastomosis groups form well-supported clades corresponding to established designations.
Generalist anastomosis groups exhibited more transient host associations, whereas specialist lineages demonstrated stronger host-associated genetic differentiation.
Ancestral host-state reconstruction revealed that the AG-3 lineage evolved from an ancestor with a broad host range to specialize exclusively on Solanaceae without subsequent host reversals.