Taxonomy, phylogeny, and divergence time estimation for <i>Apiosphaeria guaranitica</i>, a Neotropical parasite on bignoniaceous hosts.

<i>Apiosphaeria guaranitica</i>, the causal agent of brown crust disease of several bignoniaceous hosts, among them <i>Handroanthus</i> and <i>Tabebuia</i> species, has been traditionally placed in Phyllachoraceae, based exclusively on morphological studies, without supporting molecular evidence. Here we provide molecular data for the link between sexual and asexual states of the fungus, and elucidate the phylogeny of <i>A. guaranitica</i>. The multilocus phylogenetic analyses employed sequences from the 18S subunit (18S), 28S subunit (28S), and nuclear internal transcribed spacers (ITS1-5.8S-ITS2 = ITS) of the nuc rDNA, second largest subunit of RNA polymerase II (<i>RPB</i>2), and translation elongation factor 1-α (<i>TEF</i>1) genetic loci. Estimates of the divergence time of this lineage were supported by fossil-calibra-tion (FC), and secondary calibration (SC) strategies. Our results indicate a natural placement of <i>Apiosphaeria</i> within Diaporthaceae (Diaporthales), where it represents an ancient lineage of the crown-group of Diaporthaceae, diverging during the late Paleocene at 61.15 (FC) and 60.63 (SC) MYA. This divergence time estimate within Diaporthales is based on <i>Spataporthe taylori</i>, a diaporthaceous fossil.