Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/6/2011
Publication Date: 8/6/2011
Citation: Castell-Miller, C.V., Dornbusch, M.R., Samac, D.A. 2011. Multilocus analysis of Phoma sclerotioides isolates from Minnesota [abstract]. Plant Biology 2011, American Society of Plant Biologists Meeting, August 6-10, 2011, Minneapolis, Minnesota. Available: http://www.apsnet.org/meetings/Documents/2011_meeting_Abstracts/a11ma164.htm.
Technical Abstract: Phoma sclerotioides causes brown root rot in alfalfa which reduces winter survival. Regional genotypes occur, but local population structures have not been characterized. The population genetic structure and gene flow within alfalfa fields in Minnesota was inferred using multilocus analysis. Portions of chitin synthase 1 (CHS; 299 bp), glyceraldehyde-3-phosphate dehydrogenase (G3PD; 578 bp), the rDNA internal transcribed spacers (ITS; 498 bp), and their concatenated sequences (CS) (1,375 bp), were analyzed for 102 isolates from four sites. Diversity of the CS was similar for two collection years with regard to nucleotide (Pi) and haplotype (Hd) diversity, as well as Theta values, although a different number of haplotypes were found each year. Sequence of G3PD was the most diverse for Pi and Theta values among other estimators, while CHS had the highest Hd in both years. In 2007, no population differentiation was found between isolates from two sites with the CS, and abundant gene flow (Nm=31.50) was detected. In 2008, highly significant population differentiation between isolates from four sites, including the two sampled in 2007, and more restricted gene flow (Nm=1.86) was detected. Neutrality tests on the individual or joint sequences were not statistically significant. The level of nucleotide and haplotype diversity indicates that the Minnesota population is not recently introduced and nucleotide variation is mostly driven by random genetic drift.