Development of simple sequence repeat markers for bermudagrass from its expressed sequence tag sequences and preexisting sorghum SSR markers

Bermudagrass (Cynodon spp.) is extensively cultivated for forage and turf in the the southern United States and in parts of Asia, Africa, southern Europe, Australia and South America. However, few simple sequence repeat (SSR) markers are available for bermudagrass genetics research. Accordingly, the objective of this study was to develop SSR markers in bermudagrass by transferring sorghum genomic SSR primers and by exploring bermudagrass expressed sequence tags (ESTs) from the National Center for Biotechnology Information (NCBI) database. The transferability of 354 tested sorghum SSRs was 57% to C. transvaalensis T577 (2n = 2x = 18), 27% to C. dactylon Tifton 10 (2n = 6x = 54) and 22% to Zebra (2n = 4x = 36). Among the transferred SSRs, 65 primer pairs generated reproducible SSR bands across the three genotypes. From 20,237 Cynodon ESTs at NCBI, 303 designed SSR primer pairs amplified target bands in at least one of C. dactylon var. aridus (2n = 2x = 18), C. transvaalensis T577, C. dactylon cv. Tifton 10, and C. dactylon var. dactylon Zebra. Of the effective EST SSRs, 230 primer pairs produced reproducible bands in all four genotypes. The study demonstrated that EST sequences and sorghum SSR primers are useful sources for the development of SSR markers for bermudagrass. The developed SSR markers will make a valuable contribution to the molecular identification of commercial cultivars, construction of genetic maps, and marker-assisted breeding in bermudagrass.