Submitted to: Molecular Ecology Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2009
Publication Date: 6/1/2009
Citation: Wang, X.W., Good, L.L., Wadl, P.A., Johnson, D.H., Panthee, D., Scheffler, B.E., Rinehart, T.A., Stewart, N.R., Yuan, J., Stewart, N.C., Trigiano, R.N. 2009. Microsatellites from Conyza canadensis (horseweed). Molecular Ecology Resources. 9(5):1375-1379. Interpretive Summary: Conyza canadensis (horseweed), a native plant native to North America, is considered an economically important weed of many crops. It can severely reduce yield when present in high densities and is especially problematic in low- or no-tillage cropping systems. Horseweed is self-fertile (selfing) and produces large amounts seeds , which are wind-dispersed potentially over long distances. Glyphosate has been the primary herbicide used to control weeds in limited tilling cropping systems for glyphosate- resistant crops such as soybean. Glyphosate-resistant horseweed populations have developed because of this selection pressure and are common throughout the United States. Here, we report the development of microsatellites from C. canadensis using a biotin enrichment protocol and testing their cross amplification in 22 horseweed accessions from various locations in the U.S. and Canada. These and other microsatellites will be useful in assessing the genetic diversity of the species, and studying naturally occurring and geographical dispersal of glyphosate-resistant populations of the weed.
Technical Abstract: Microsatellite loci were identified from Conyza canadensis (horseweed). Primer pairs for 64 loci were developed and of these eight were optimized and screened using genomic DNA from 22 accessions of horseweed from North America. Most loci were polymorphic and the number of alleles per locus ranged from 1 to 8. Observed heterozygosity ranged from 0 to 0.14 and expected heterozygosity ranged from 0.0 to 0.78. These and other microsatellites will be useful in seed dispersal and population studies of naturally occurring glyphosate-resistant plants.