A phylogenetic re-evaluation of Phyllosticta (Botryosphaeriales)

Area of Science:

• Mycology
• Plant Pathology
• Fungal Taxonomy

Background:

• Phyllosticta is a widespread fungal genus with a broad host range, posing challenges in classification.
• Previous morphological studies often grouped diverse taxa, obscuring species-specific identities and phylogenetic relationships.

Purpose of the Study:

• To redefine the genus Phyllosticta using molecular data.
• To clarify the phylogenetic position of Phyllosticta within the Dothideomycetes.
• To resolve taxonomic ambiguities and identify new species within the Phyllosticta genus.

Main Methods:

• Multigene DNA phylogenetic analysis using ITS, LSU, ACT, TEF, and GPDH gene regions.
• Phylogenetic analysis of 129 Phyllosticta isolates representing approximately 170 species names.
• Morphological examination and taxonomic revisions based on molecular data.

Main Results:

• Phyllosticta is confirmed to cluster sister to Botryosphaeriaceae, leading to the resurrection of the Phyllostictaceae family name.
• Approximately 170 previously recognized species names were investigated, with many identified as synonyms of Phyllosticta capitalensis.
• Twelve new Phyllosticta species were described, and epitype/neotype specimens were designated for seven additional species.
• Phyllosticta citrimaxima was identified on Citrus maxima fruit in Thailand, contributing to the citrus black spot complex.

Conclusions:

• The study provides a revised taxonomic framework for Phyllosticta, establishing its phylogenetic placement and clarifying species boundaries.
• The findings highlight the extensive synonymy within the genus and the need for further taxonomic work on species complexes.
• The identification of new species and the reclassification of existing ones contribute to a better understanding of Phyllosticta diversity and evolution.