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Tan spot of pyrethrum is caused by a Didymella species complex


Pearce, TL and Scott, JB and Crous, PW and Pethybridge, SJ and Hay, FS, Tan spot of pyrethrum is caused by a Didymella species complex, Plant Pathology, 65, (7) pp. 1170-1184. ISSN 0032-0862 (2016) [Refereed Article]

Copyright Statement

Copyright 2015 British Society for Plant Pathology

DOI: doi:10.1111/ppa.12493


Tan spot is a disease of pyrethrum (Tanacetum cinerariifolium) in Australia. Recent increases in the severity and incidence of the disease have prompted a re-evaluation of the pathogen, originally described as Microsphaeropsis tanaceti, including its phylogenetic relationships and morphology. Nucleotide comparison of partial sequences of the nuclear ribosomal internal transcribed spacer, β-tubulin, large subunit 28S nrDNA (LSU), actin and glyceraldehyde-3-phosphate dehydrogenase loci identified two distinct haplotypes within the species. Haplotype differentiation was consistent for each locus, except for the LSU, within which sequences were identical across all isolates. Morphological variation, especially culture pigmentation and conidial size, consistently supported the phylogenetic data distinguishing two haplotypes. Phylogenetic comparisons of M. tanaceti incorporating 98 Didymellaceae species did not associate the M. tanaceti haplotypes with the genus Microsphaeropsis. The two M. tanaceti haplotypes were closely related, and clustered in the Didymella sensu stricto clade. Based on these phylogenetic results, supported by their distinct morphology and cultural characteristics, the two haplotypes of M. tanaceti are reclassified as two species of Didymella, namely D. rosea and D. tanaceti. The implications of two closely related species causing tan spot of pyrethrum are discussed.

Item Details

Item Type:Refereed Article
Keywords:Didymellaceae, multilocus, phylogenetics, taxonomy
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Horticultural production
Research Field:Horticultural crop protection (incl. pests, diseases and weeds)
Objective Division:Plant Production and Plant Primary Products
Objective Group:Industrial crops
Objective Field:Plant extract crops
UTAS Author:Pearce, TL (Dr Tamieka Pearce)
UTAS Author:Scott, JB (Dr Jason Scott)
ID Code:109907
Year Published:2016
Web of Science® Times Cited:19
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2016-07-06
Last Modified:2017-11-06

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