Diaporthe amygdali, a species complex or a complex species?

Area of Science:

• Mycology
• Evolutionary Biology
• Phylogenetics

Background:

• Accurate species delimitation is crucial for understanding fungal diversity and evolution.
• The fungal genus Diaporthe presents challenges in species boundary definition.
• The Diaporthe amygdali complex is a monophyletic group with unclear species limits.

Purpose of the Study:

• To clarify species boundaries within the Diaporthe amygdali complex.
• To evaluate the efficacy of the Genealogical Concordance Phylogenetic Species Recognition principle (GCPSR).
• To assess the utility of coalescent-based models (GMYC and PTP) for species delimitation.

Main Methods:

• Analysis of combined multilocus DNA sequences.
• Application of the Genealogical Concordance Phylogenetic Species Recognition principle (GCPSR).
• Utilized coalescent-based models: General Mixed Yule-Coalescent (GMYC) and Poisson Tree Processes (PTP).

Main Results:

• Incongruence between individual gene phylogenies and coalescent methods did not support distinct species within the complex.
• Evidence suggests the absence of reproductive isolation and gene flow barriers.
• The Diaporthe amygdali complex is determined to be a single species.

Conclusions:

• The Diaporthe amygdali complex represents a single species, challenging previous assumptions.
• The Genealogical Concordance Phylogenetic Species Recognition principle (GCPSR) is vital for accurate species delimitation.
• Coalescent methods provide robust tools for refining species boundaries in fungal genera like Diaporthe.