Comparison of newly synthetic hexaploid wheat with its donors on SSR products

Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the construction of genetic segregation population for SSR markers. However, data on the evolution of microsatellites during the polyploidization event of hexaploid wheat are limited. In this study, 66 pairs of specific to A/B genome SSR patterns among newly synthesized hexaploid wheat, the donor tetraploid wheat and Aegilops tauschii were compared. The results indicated that most SSR markers were conserved during the polyploidization events of newly synthetic hexaploid wheat, from Triticum turgidum and Ae. tauschii. Over 70% A/B genome specific SSR markers could amplify the SSR sequences from the D genome of Ae. tauschii. Most amplified fragments from Ae. tauschii were detected in synthetic hexaploid at corresponding positions with the same sizes and patterns as in its parental Ae. tauschii. This suggested that these SSR markers, specific for A/B genome in common wheat, could amplify SSR products of D genome besides A/B genome in the newly synthesized hexaploid wheat, that is, these SSR primers specific for A/B genome in common wheat were nonspecific for the A/B genome in the synthetic hexaploid wheat. In addition, one amplified Ae. tauschii product was not detected in the newly synthetic hexaploid wheat. An extra-amplified product was found in the newly synthetic hexaploid wheat. These results suggested that caution should be taken when using SSR marker to genotype newly synthetic hexaploid wheat.