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

Vaghefi, Niloofar and Hay, Frank S. and Ades, Peter K. and Pethybridge, Sarah Jane and Ford, Rebecca and Taylor, Paul W. J. (2015) Rapid changes in the genetic composition of Stagonosporopsis tanaceti population in Australian pyrethrum fields. Phytopathology, 105 (3). pp. 358-369. ISSN 0031-949X

Abstract

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.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version cannot be displayed due to copyright restrictions.
Faculty / Department / School: No Faculty
Date Deposited: 23 Aug 2017 03:22
Last Modified: 07 Feb 2018 02:10
Fields of Research : 06 Biological Sciences > 0607 Plant Biology > 060704 Plant Pathology
06 Biological Sciences > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Identification Number or DOI: 10.1094/PHYTO-08-14-0212-R
URI: http://eprints.usq.edu.au/id/eprint/32945

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