Large-spored Alternaria pathogens in section Porri disentangled
J H C Woudenberg1, M Truter2, J Z Groenewald3
1CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, Netherlands ; WUR, Laboratory of Phytopathology, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands.
Studies in Mycology
|December 11, 2014
Summary
This study reclassifies the fungal genus Alternaria section Porri, describing 10 new species and synonymizing 27, clarifying pathogen identification for diseases like early blight and purple blotch.
Area of Science:
- Mycology
- Plant Pathology
- Molecular Phylogenetics
Background:
- The fungal genus Alternaria is ubiquitous and was recently divided into 24 sections.
- Alternaria section Porri is the largest, encompassing species with medium to large conidia and long beaks, including significant plant pathogens.
- Accurate species identification is crucial for understanding and managing plant diseases.
Purpose of the Study:
- To revise the taxonomy of Alternaria section Porri using multi-gene phylogenetics and morphological data.
- To clarify species boundaries and identify causal agents of economically important plant diseases.
- To describe new species and synonymize existing names within Alternaria section Porri.
Main Methods:
- Construction of a multi-gene phylogeny using ITS, GAPDH, RPB2, TEF1, and Alt a 1 gene regions.
- Supplementation of molecular data with morphological and cultural studies for species recognition.
- Comparative analysis of isolates causing specific plant diseases.
Main Results:
- Recognition of 63 species within Alternaria section Porri, including 10 newly described species.
- Synonymization of 27 previously recognized species names.
- Clarification of early blight pathogens on tomato (synonymized under A. linariae) and potato (A. protenta, A. solani, A. grandis).
- Confirmation of A. allii and A. porri causing onion purple blotch, with challenges in distinguishing them based on beak and branch numbers.
- Delineation of three species affecting Passifloraceae, reducing the previous count from four.
- Identification of three species affecting sweet potato, including two new species.
- Description of a new Alternaria section with two large-spored species possessing concatenate conidia.
Conclusions:
- The taxonomic revision of Alternaria section Porri provides a more robust species concept based on integrated data.
- Accurate identification of Alternaria species is essential for effective disease management strategies in agriculture.
- This study contributes significantly to the understanding of Alternaria diversity and its role as plant pathogens.
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