Transferability of SSR markers in the grass family.

摘要

Simple sequence repeat (SSR) markers are a valuable tool suitable for many genetic studies but their initial development is costly, time consuming and labor intensive. Based on the conservation of gene content and order among closely related species, transferability, application of existing SSR markers from one species in another species, is considered as an alternative way to obtain SSR markers. Our objectives were to examine (1) the transferability of SSR markers among wheat (Triticum aestivum L.), rye ( Secale cereale L.) and triticale (x Triticosecale Wittmack); (2) the genetic diversity of hexaploid triticale accessions using wheat and rye SSR markers; and (3) transferability in 11 agronomically important grass genera using SSR markers from rice (Oryza sativa L.), sorghum (Sorghum bicolor L.) and wheat. Transferability of 148 wheat SSR markers to rye was 17%, whereas 25% of 28 rye markers were amplifiable in wheat. In triticale, 58% and 39% transferability was achieved for wheat and rye markers, respectively. In the genetic diversity study of 80 hexaploid triticale accessions, 43 wheat and 14 rye SSR markers detected an average gene diversity of 0.54. Cluster analysis grouped the accessions into 5 clusters that were generally consistent with the available pedigree information, country of origin, growth habit, and release year. Every larger cluster, however, included lines with unrelated pedigrees, different countries of origin, growth habit, and release year. Transferability of 20 SSR markers each of rice, sorghum and wheat in 11 grass genera yielded none to multiple amplification products in non-donor genera. The alignment of sequences amplified by Xcup61, a sorghum marker, showed the homologous fragment amplified in sugar cane (Saccharum officinarum L.), a closely related genus, but not in distant genera, wheat, triticale and barley (Hordeum vulgare L.). Overall results indicated that the SSR markers were transferable in the closely related species and could be used in the genetic studies. However, the amplification products of non-donor species should be sequenced to ensure their homology.