Temporal genetic differentiation of Cercospora beticola populations in New York Table beet fields

Knight, Noel L. and Vaghefi, Niloofar and Hansen, Zachariah R. and Kikkert, Julie R. and Pethybridge, Sarah J. (2018) Temporal genetic differentiation of Cercospora beticola populations in New York Table beet fields. Plant Disease, 102 (11). pp. 2074-2082. ISSN 0191-2917


Annual epidemics of Cercospora leaf spot (CLS), caused by the fungus Cercospora beticola, can result in substantial defoliation in table beet fields in New York. High allelic and genotypic diversity have been described within C. beticola populations; however, information on the temporal stability of populations is lacking. C. beticola isolates were obtained from symptomatic leaves in three table beet fields in successive years. Two of the fields were organic mixed-cropping farms and the third was managed conventionally in a broad-acre cropping system. C. beticola isolates (n = 304) were genotyped using 12 microsatellite markers. Genotypic diversity (Simpson's complement index = 0.178 to 0.990), allele frequencies, and indices of differentiation between years varied. Pairwise index of differentiation values ranged from 0.02 to 0.25 for clone-corrected data, and indicated significant genetic differentiation at Farm 2. No multilocus genotype was shared between years. The shift in multilocus genotypes between years questions the role of clonally reproducing primary inoculum. Collectively, these results suggest that a dominant inoculum source for initiating annual CLS epidemics is external to the field of interest. These findings have implications for CLS disease management in conventional and organic table beet production.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Crop Health
Date Deposited: 17 Mar 2019 23:52
Last Modified: 22 Apr 2019 23:44
Uncontrolled Keywords: sugar beet; Cercospora beticola; C beticola
Fields of Research : 06 Biological Sciences > 0607 Plant Biology > 060704 Plant Pathology
06 Biological Sciences > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics
Identification Number or DOI: 10.1094/PDIS-01-18-0175-RE
URI: http://eprints.usq.edu.au/id/eprint/36094

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