Fig 1.
Phylograms of the homeodomain locus (A) and pheromone/receptor homologues (B) in 8 families of Pucciniales: Araucariomycetaceae, Coleosporiaceae, Melampsoraceae, Phragmidiaceae, Pucciniaceae, Skierkaceae, Sphaerophgramiaceae and Zaghouaniaceae. Genes at the homeodomain locus (HD1 and HD2) are suspected to regulate mating compatibility in rust fungi and are present in all suborders of Pucciniales.
Fig 2.
Potential models for exchange of nuclei in life cycles of rust fungi.
(A) The standard sexual life cycle of macrocyclic, heteroecious rust fungi. (B) Exchange of nuclei in sexual reproduction with haplotypes fertilised by spermatia. (C) Hypothetical exchange of nuclei between dikaryotic hyphae of rust fungi in somatic hybridisation. (D) Hypothetical exchange of nuclei between monokaryotic and dikaryotic hyphae in di-mon mating, whether (i) nuclei from the dikaryotic hyphae of a fertilised spermogonium/aecium are donated to an unfertilised spermogonium; or (ii) nuclei are donated to potential monokaryotic hyphal growth. Multiple pathways in the illustrated figure lead to identical genotypes in blue rectangles.