Stem cankers on sunflower (Helianthus annuus) in Australia reveal a complex of pathogenic Diaporthe (Phomopsis) species

Thompson, S. M. and Tan, Y. P. and Young, A. J. and Neate, S. M. and Aitken, E. A. B. and Shivas, R. G. (2011) Stem cankers on sunflower (Helianthus annuus) in Australia reveal a complex of pathogenic Diaporthe (Phomopsis) species. Persoonia: Molecular Phylogeny and Evolution of Fungi, 27. pp. 80-89. ISSN 0031-5850

Abstract

The identification of Diaporthe (anamorph Phomopsis) species associated with stem canker of sunflower (Helianthus annuus) in Australia was studied using morphology, DNA sequence analysis and pathology. Phylogenetic analysis revealed three clades that did not correspond with known taxa, and these are believed to represent novel species. Diaporthe gulyae sp. nov. is described for isolates that caused a severe stem canker, specifically pale brown to dark brown, irregularly shaped lesions centred at the stem nodes with pith deterioration and midstem lodging. This pathogenicity of D. gulyae was confirmed by satisfying Koch's Postulates. These symptoms are almost identical to those of sunflower stem canker caused by D. helianthi that can cause yield reductions of up to 40% in Europe and the USA, although it has not been found in Australia. We show that there has been broad misapplication of the name D. helianthi to many isolates of Diaporthe (Phomopsis) found causing, or associated with, stem cankers on sunflower. In GenBank, a number of isolates had been identified as D. helianthi, which were accommodated in several clades by molecular phylogenetic analysis. Two less damaging species, D. kochmanii sp. nov. and D. kongii sp. nov., are also described from cankers on sunflower in Australia.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2011 Nationaal Herbarium Nederland & Centraalbureau voor Schimmelcultures. Published version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 12 Jun 2014 05:54
Last Modified: 09 Feb 2017 05:11
Uncontrolled Keywords: Diaporthe gulyae; Diaporthe kochmanii; Diaporthe kongii; ITS; phylogeny; sunflower taxonomy; TEF-1ALPHA
Fields of Research : 06 Biological Sciences > 0603 Evolutionary Biology > 060310 Plant Systematics and Taxonomy
06 Biological Sciences > 0605 Microbiology > 060505 Mycology
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970106 Expanding Knowledge in the Biological Sciences
Identification Number or DOI: 10.3767/003158511X617110
URI: http://eprints.usq.edu.au/id/eprint/25194

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