The taxonomic history of Ceratocystis (Ceratocystidaceae), a genus that includes many improtant plant pathogens has been complicated and remains a topic of active debate. This is a consequence of the fact that many of the commonly used species recognition concepts (morphological, biological) are violated in this group. Species delineation in Ceratocystis thus has relied predominantly on genealogical concordance phylogenetic species recognition (GCPSR) using multiple markers, including the Internal Transcribed Spacer (ITS) region, β-tubulin and translation elongation factor 1-α. Recent research has however provided evidence of intragenomic variation of ITS, as well as genealogical discordance in isolates belonging to what has been referred to as the Latin-American clade (LAC). This phylogenetic incongruence is not limited to the LAC and increasing numbers of new species are displaying this variation in Ceratocystis. In this study, we examined the extent of phylogenetic incongruence in Ceratocystis using a phylogenomics approach, and explored the potential role of hybridization as the source of this incongruent signal. The results showed that incongruence is extensive in Ceratocystis, particularly in species of the LAC, which was typified by three equally represented topologies. The role of hybridization as the potential source of discordance requires further research. This is particularly because, the results in this study can also be explained by high levels of shared ancestral polymorphism in this recently diverged lineage. This study is the first to apply a phylogenomics approach to resolve species boundary questions in Ceratocystis.
No datasets are available for this submission.