Population structure of Cylindrocladium parasiticum infecting peanuts (Arachis hypogaea) in Georgia, USA
- First Online:
- 134 Downloads
Cylindrocladium parasiticum is an important pathogen of peanut (Arachis hypogaea) causing the disease Cylindrocladium black rot. The genetic structure of this haploid pathogen was determined for populations associated with peanut in Georgia, USA. Ten polymorphic microsatellite markers were used to determine genetic and genotypic diversity among three sub-populations representing the geographic distribution of peanut production in Georgia. Among 200 isolates collected, only 10 unique multilocus haplotypes were identified, with one multilocus haplotype occurring 176 times. Although no evidence for random mating was observed, the existence of loops in a constructed haplotype network hint at the possibility of recombination events. The absence of random mating might therefore be attributed to the homothallic nature of C. parasiticum as well as the clonality of the population, without excluding the possible occurrence of recombination. Cylindrocladium parasiticum thus appears to consist of a genetically homogeneous population throughout Georgia with mainly clonal reproduction or inbreeding contributing to the observed population genetic structure.
KeywordsCalonectria ilicicola Haplotype network Homothallic Microsatellites Population genetics Simple sequence repeat (SSR)
Cylindrocladium black rot
Indistinguishable multilocus haplotypes
Distinguishable multilocus haplotypes
- Bell, D. K., & Sobers, E. K. (1966). A peg, pod, and root necrosis of peanuts caused by a species of Calonectria. Phytopathology, 56, 1361–1364.Google Scholar
- Bell, D. K., Locke, B. J., & Thompson, S. S. (1973). The status of Cylindrocladium black rot of peanut in Georgia since its discovery in 1965. Plant Disease Reporter, 57, 90–94.Google Scholar
- Brenneman, T. (2003). Use of fumigation and resistant cultivars to manage Cylindrocladium black rot (CBR). In: T. B. Brenneman, & C. L. Butts (Eds.), 2003 Georgia peanut research-extension report (pp. 76–82). Dawson: USDA. Retrieved November 20, 2008, from http://www.ars.usda.gov/sp2UserFiles/Place/66040000/ResearchandExtensionReports/2003GAReport.pdf.
- Hood, G. (2008). PopTools version 3.0.6. Retrieved February, 2009, from PopTools, CSIRO Australia Web site: http://www.cse.csiro.au/poptools/download.htm.
- Krigsvold, D. T., Garren, K. H., & Griffin, G. J. (1977). Importance of peanut field cultivation and soybean cropping in the spread of Cylindrocladium crotalariae within and among peanut fields. Plant Disease Reporter, 61, 495–499.Google Scholar
- Rowe, R. C., Johnston, S. A., & Beute, M. K. (1974). Formation and dispersal of Cylindrocladium crotalariae microsclerotia in infected peanut roots. Phytopathology, 64, 1294–1297.Google Scholar
- Yeh, F. C., Yang, R., & Boyle, T. (1999). POPGENE Version 1.31: Microsoft window-based freeware for population genetic analysis. University of Alberta and Centre for International Forestry Research.Google Scholar