Submitted to: Fungal Genetics Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2005
Publication Date: March 15, 2005
Citation: Szabo, L.J., Nguyen, K.P. 2005. Development of simple sequence repeat markers for Puccinia graminis and P. triticina. Fungal Genetics Newsletter. 52:S72. Technical Abstract: Rusts are obligate plant parasitic fungi with a complex life cycle that often includes five different spore stages. As a result, molecular studies are often performed with the asexual, dikaryotic uredinial stage (urediniospores) using dominant markers (RAPDs, AFLPs). Currently, molecular genetic and population genetic studies are underway with the wheat rust fungi Puccinia graminis f.sp. tritici and P. triticina, the causal agents of wheat stem rust and wheat leaf rust, respectively. The lack of co-dominant molecular markers for genetic analysis has been a significant impediment. Simple sequence repeat (SSR) enriched libraries were constructed from P. graminis and P. triticina genomic DNA. Approximately 200 clones from each library were screened and sequenced. Sixty SSR markers have been developed from the P. graminis clones and the majority consist of di-nucleotide (AG and GT) repeats ranging from 10 to 28 repeats in length. Eleven of the repeats were complex and often contained degenerate motifs. Thirty of the markers have been screened against 10 P. graminis North American isolates, 27 of which were polymorphic and detected from 2 to 10 alleles per marker. Fifty-six markers have been developed from the P. triticina clones, the majority of which consist of di-nucleotide (AG and GT) repeats and 13 consist of tri-nucleotide repeats (CAA). Screening of these markers against a select set of P. triticina isolates has begun.