Colletotrichum tanaceti, the causal agent of anthracnose, is an emerging pathogen of commercially grown pyrethrum (Tanacetum cinerariifolium) in Australia. A microsatellite marker library was developed to understand the spatio-genetic structure over three sampled years and across two regions where pyrethrum is cultivated in Australia. Results indicated that C. tanaceti was highly diverse with a mixed reproductive mode; comprising both sexual and clonal reproduction. Sexual reproduction of C. tanaceti was more prevalent in Tasmania than in Victoria. Little differentiation was observed among field populations likely due to isolation by colonization but most of the genetic variation was occurring within populations. Colletotrichum tanaceti was likely to have had a long-distance gene and genotype flow among distant populations within a state and between states. Anthropogenic transmission of propagules and wind dispersal of ascospores are the most probable mechanisms of long-distance dispersal of C. tanaceti. Evaluation of putative population histories suggested that C. tanaceti most likely originated in Tasmania and expanded from an unidentified host onto pyrethrum. Victoria was later invaded by the Tasmanian population. With the mixed mode of reproduction and possible long-distance gene flow, C. tanaceti is likely to have a high evolutionary potential thereby has ability to adapt to management practices in future.

Item Type:	Refereed Article
Keywords:	pyrethrum, Colletotrichum tanaceti, population structure, evolutionary potential, origin, anthracnose, population biology, ascomycetes
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Horticultural Production
Research Field:	Horticultural Crop Protection (Pests, Diseases and Weeds)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Industrial Crops
Objective Field:	Plant Extract Crops (e.g. Pyrethrum, Jojoba)
UTAS Author:	Scott, JB (Dr Jason Scott)
ID Code:	133104
Year Published:	2019
Deposited By:	TIA - Research Institute
Deposited On:	2019-06-11
Last Modified:	2019-10-15
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