Plant & Animal Genome VI Conference

P56

DEVELOPMENT OF AG-REPEAT MICROSATELLITE MARKERS FOR WILD AND CULTIVATED RICE SPECIES (ORYZA spp.)

1. Laboratorio de Biotecnologia , Embrapa/CNPT, cp 569 , Passo Fundo, RS, Brazil
2. Laboratorio de Genetica de Plantas, Embrapa/Cenargen, cp 02372, Brasilia, DF, Brazil

Microsatellites are short tandem repeat sequences of nucleotides distributed throughout the eukaryotic genomes. Among the several classes of molecular markers, microsatellite loci stand out as codominant markers with high information content such as high number of alleles per locus, high polymorphism and high expected heterozygosity value. The objective of this work was to develop a set of primers that amplify AG-rich regions of the Oryza genome that could be used for population genetic studies of Oryza species, as well as genetic diversity, mapping and marker-assisted selection of Oryza sativa. AG-repeat enriched libraries were developed from total DNA extracted from young leaves of the South-American wild rice O. glumaepatula and the cultivated rice O. sativa. The AG-rich clones were then sequenced and specific primers complementary to flanking regions of the microsatellite loci were designed and synthesized. Eleven microsatellite loci from O. glumaepatula AG-rich clones were studied in 30 cultivated rice varieties commonly used in upland and irrigated rice breeding programs. The conservation of these eleven microsatellites were evaluated in 33 wild rice accessions representing the diploid (AA, BB, CC, EE and FF) and tetraploid (CCDD and BBCC) rice genomes. Microsatellite alleles were identified after ethidium bromide staining of metaphor gel electrophoresis of PCR products. Alleles at the eleven microsatellite loci could be amplified in all rice species tested representing the five diploid and two tetraploid genomes, indicating a high level of conservation of these loci in the different species. Heterozigosity estimates of cultivated rice varieties and wild rice accessions were made for each microsatellite locus. The conservation of microsatellite loci in Oryza species and the high information content of these loci highly recommend the use of these markers in population genetics studies and mapping efforts in interspecific and intraspecific crosses of rice. Financial support: CAPES, PADCT/CNPq