Publikationsdatum:
2024-01-12
Beschreibung:
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\xe2\x80\x99s 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.
Schlagwort(e):
Diaporthe gulyae
;
Diaporthe kochmanii
;
Diaporthe kongii
;
ITS
;
phylogeny
;
sunflower taxonomy
;
TEF-1\xce\xb1
Repository-Name:
National Museum of Natural History, Netherlands
Materialart:
info:eu-repo/semantics/article
Format:
application/pdf
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