Differential transferability of EST-SSR primers developed from the diploid species Pseudoroegneria spicata, Thinopyrum bessarabicum, and Thinopyrum elongatum

Simple sequence repeat technology based on expressed sequence tag (EST-SSR) is a useful genomic tool for genome mapping, characterizing plant species relationships, elucidating genome evolution, and tracing genes on alien chromosome segments. EST-SSR primers developed from three perennial diploid species of Triticeae, Pseudoroegneria spicata (Pursh) Á. Löve (having St genome), Thinopyrum bessarabicum (Savul. & Rayss) Á. Löve (J b = E b = J), and Thinopyrum elongatum (Host) D.R. Dewey (J e = E e = E), were used to produce amplicons in these three species to (i) assess relative transferability, (ii) identify polymorphic species-specific markers, and (iii) determine genome relationships among the three species. Because of the close relationship between J b and J e genomes, EST-SSR primers derived from Th. bessarabicum and Th. elongatum had greater transferability to each other than those derived from the St-genome P. spicata. A large number of polymorphic species- and genome-specific EST-SSR amplicons were identified that will be used for construction of genetic maps of these diploid species, and tracing economically useful genes in breeding or gene transfer programs in various species of Triticeae.