Development and Characterization of Simple Sequence Repeat (SSR) Markers for St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze).

St. Augustinegrass is a commonly used turfgrass across the southeastern US for its superior shade tolerance, stoloniferous growth habit, and moderately low input requirements compared to other warm season grasses. Despite the wide range of molecular markers currently available and the progress made in the application of these tools to several turfgrass species, marker development in St. Augustinegrass has been extremely limited. The development of a robust set of informative markers would be necessary for effective genetic characterization of this species’ genome. Simple sequence repeat (SSR) markers are highly informative, reproducible, and automatable, making them widely applicable in plant improvement. The objectives of this study were to (i) increase the pool of informative molecular markers for this species by isolating genomic SSRs, and (ii) use these markers to characterize the genetic diversity amongst Stenotaphrum germplasm. For these purposes, a genomic library from cultivar ‘Raleigh’ was developed for sequencing. A total of 25,011 sequences flanking SSR regions were identified from Illumina sequencing data.  131 SSR primer pairs were designed and evaluated for amplification and polymorphism on a diverse panel of 42 cultivars and plant introductions. The efficiency of amplification was 94%. Polymorphism was observed for every amplified marker, with a range of two to seven alleles per locus. Moreover, high levels of transfer to Pembagrass, another member of the Stenotaphrum genus, were observed.  These markers are a valuable resource for genetic studies and breeding applications in St. Augustinegrass.