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Characterization of nuclear microsatellite markers from Agrostis species
Citation:
REICHMAN, J. R., B. SMITH, AND L. S. WATRUD. Characterization of nuclear microsatellite markers from Agrostis species. Presented at Botany 2008 Conference, Vancouver, AB, CANADA, July 26 - 30, 2008.
Impact/Purpose:
Agrostis stolonifera L. (creeping bentgrass) is a widely distributed, out-crossing, wind-pollinated, perennial grass that has been genetically engineered for a variety of traits including herbicide, disease and insect resistance.
Description:
Agrostis stolonifera L. (creeping bentgrass) is a widely distributed, out-crossing, wind-pollinated, perennial grass that has been genetically engineered for a variety of traits including herbicide, disease and insect resistance. This allotetraploid species (A2A2A3A3 genomic compliment) is sexually compatible with at least 12 other species present in North America and recent transgene escapes from field test plots and persistence within wild populations have been documented in the USA. Given the possibility of future transgene flow out of engineered creeping bentgrass cultivars, population-level markers are needed to improve identification of hybrids (F1 crop X wild and backcross progeny) and to analyze structural changes in wild populations that may be associated with transgene introgression. In addition, genome-specific markers would simplify population analyses for allopolyploids. We have enriched nuclear microsatellite libraries directly from accessions of A. stolonifera cultivar Crenshaw, a wild A. stolonifera population and from the diploid A. transcaspica (putative A3A3) for clones containing AC, AG, AAC, AAG, ATG, AGG and GAAT motif repeats. Six hundred ninety clones were sequenced. Primers designed from 88 clones containing microsatellites were screened for amplification specificity against a reference panel including the source taxa plus A. gigantea (A1A1A2A2A3A3), A. capillaris (A1A1A2A2), A. castellana (A1A1A2A2) and A. canina (A1A1). Of these, 42 primer pairs correctly amplified homologous loci which are being evaluated for size heterogeneity between individuals within the Agrostis accessions. We now have identified 8 loci that appear to have informative polymorphisms, and plan to expand this number to at least 12 for further testing on natural Agrostis populations. Methods developed for assessing ecological safety of open-pollinating transgenic bentgrass cultivars will also be useful for studies on population biology and phylogeography of Agrostis species.