Microsatellite DNA polymorphism divergence in Triticum dicoccoides accessions highly resistant to yellow rust

T. Fahima, M. S. Röder, A. Grama, E. Nevo

Research output: Contribution to journalArticlepeer-review

Abstract

Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat throughout the world. Wild emmet wheat, Triticum dicoccoides, the progenitor of cultivated wheat, was found to be a valuable source for novel stripe-rust-resistance genes. The objective of the present study was to estimate the extent of genetic diversity among the wild emmer wheat accessions, previously identified as highly resistant to stripe rust, in order to select suitable parents for genetic-mapping studies. Twenty three wheat microsatellite (WMS) markers were used to detect DNA polymorphism among 21 accessions of T. dicoccoides, which included 19 resistant and two susceptible accessions originating mainly from the center of origin and diversity in the Upper Galilee and Hermon Mountain in northern Israel. In addition, two Triticum durum and one Triticum aestivum lines were also included in the analysis. The 23 WMS markers used were located on 23 chromosome arms, representing all 14 chromosomes of genomes A and B of wheat, and revealed a total of 230 alleles. The number of alleles ranged from 5 to 18, with an average of ten alleles per WMS. Genetic dissimilarity values between genotypes, calculated by the WMS-derived data, were used to produce a dendrogram of the relationships among accessions using the unweighted pair-group method with arithmetic averages (UPGMA). The results showed that all of the wild emmet wheat accessions could be distinguished. Most of the resulting groups were strongly related to the ecogeographical origin of the accessions, indicating that the genetic diversity of T. dicoccoides is correlated with geographic distribution. The three major groups were the Rosh Pinna group (north of the Sea of Galilee), the Mount Hermon group (north of the Golan Heights) and Mount Kena'an group (Upper Galilee). The genetic similarity (GS) of the 21 T. dicoccoides accessions based on WMS results averaged 0.31. As expected, the T. durum and T. aesthivum lines were grouped separately from the T. dicoccoides accessions. The results obtained suggest that a relatively small number of microsatellites can be used for the estimation of genetic diversity in wild material of T. dicoccoides. These results will be useful in the identification of suitable parents for the development of mapping populations for tagging yellow-rust resistance genes derived from T. dicoccoides. Furthermore, future work could test the adaptive evolutionary significance of microsatellites in natural populations of wild emmet wheat.

Original languageEnglish
Pages (from-to)187-195
Number of pages9
JournalTheoretical And Applied Genetics
Volume96
Issue number2
DOIs
StatePublished - Feb 1998

Keywords

  • Genetic diversity
  • Microsatellite markers
  • Stripe rust
  • Triticum dicoccoides
  • Wheat

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Genetics

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