Genetic entanglement between Cercospora species associating Soybean Purple Seed Stain

GUILLIN, EA; GOTTLIEB, A. M.; GRIJALBA PE; OLIVEIRA LO

MYCOLOGICAL PROGRESS

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2017

1617-416X

Soybean Purple Seed Stain (S-PSS) isa destructive, worldwide distributed fungal disease of caused by several Cercospora species. This work aims toshed light into the nature of the genealogical and genetic relationshipsamongst S-PSS causal agents. Fungal isolates were obtained from Argentina andBrazil that belong to the leading countries in soybean production worldwide.DNA sequences were obtained from eight loci across the collection of isolates. Relationshipswere evaluated through Bayesian phylogenetic inferences, and distance andcharacter-based network analyses and discriminant analyses. Occurrence of reticulateevolutionary events was tested with recombination tests. The high haplotypediversity (H = 1.0) was arranged in four validated haplogroups. Reticulatenetwork topologies were evident, and 11 recombination events were validatedthrough several tests. Five of these events occurred across species boundaries.Comparison with sequences from 70 Cercosporaspecies indicated that at least five monophyletic groups of S-PSS causing agentsare currently present in South America. The provided evidence supports thehypothesis that interspecific genetic exchange plays a significant role in theevolutionary dynamics of Cercosporaspecies in this region. The occurrence of interspecific recombination hasimplications for understanding epidemiological threats to soybean productionthat appear to be more serious than previously anticipated.