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Rapid changes in the genetic composition of Stagonosporopsis tanaceti population in Australian pyrethrum fields


Vaghefi, N and Hay, FS and Ades, PK and Pethybridge, SJ and Ford, R and Taylor, PWJ, Rapid changes in the genetic composition of Stagonosporopsis tanaceti population in Australian pyrethrum fields, Phytopathology, 105, (3) pp. 358-369. ISSN 0031-949X (2015) [Refereed Article]

Copyright Statement

2015 The American Phytopathological Society

DOI: doi:10.1094/PHYTO-08-14-0212-R


A novel set of microsatellite markers were developed and employed for geographical and temporal population analyses of Stagonosporopsis tanaceti, the cause of ray blight of pyrethrum in Australia. Genotyping of 407 isolates, using 13 markers, suggested an asexual mode of reproduction with significant linkage disequilibrium and high levels of clonality. Low geographical differentiation and widespread distribution of a few multilocus genotypes (MLGs), in the absence of airborne ascospores, suggested the role of human-mediated movement of seed as a major means of long-distance pathogen dispersal. The genetic composition of S. tanaceti was stable for a decade then changed rapidly in only 2 years. Bayesian clustering analyses and minimum spanning networks determined only two major clonal lineages in and prior to 2010. However, in 2012, a previously unobserved cluster of MLGs was detected, which significantly increased in frequency and displaced the historically dominant MLGs by 2013. This rapid change in the genetic composition of S. tanaceti could indicate a second introduction then a selective sweep, or strong selection pressures from recently introduced fungicides or pyrethrum varieties. These results may have serious implications for durability of management strategies for this disease.

Item Details

Item Type:Refereed Article
Keywords:microsatellite development, S chrysanthemi, S inoxydabilis, temporal population genetics
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant pathology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Industrial crops
Objective Field:Plant extract crops
UTAS Author:Hay, FS (Dr Frank Hay)
ID Code:105995
Year Published:2015
Web of Science® Times Cited:12
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2016-01-22
Last Modified:2016-05-10

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