Distribution and nucleotide diversity of Yr15 in wild emmer populations and chinese wheat germplasm

Yu He, Lihua Feng, Yun Jiang, Lianquan Zhang, Jun Yan, Gang Zhao, Jirui Wang, Guoyue Chen, Bihua Wu, Dengcai Liu, Lin Huang, Tzion Fahima

Research output: Contribution to journalArticlepeer-review

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating fungal disease of wheat. The wild emmer gene, Yr15 (Wtk1), which confers a strong broad-spectrum resistance to Pst isolates, is composed of kinase and pseudokinase domains. The analysis of 361 wild emmer accessions from a wide range of natural habitats confirms that functional Wtk1 is distributed mainly along a narrow axis from Mt. Carmel to Mt. Hermon regions, in the northern part of Israel, where environmental conditions are favorable to the onset of stripe rust. An analysis of full-length Wtk1 DNA sequences from 49 wild emmer accessions identified three haplotypes and extremely low nucleotide diversity (π = 0.00002). The sequence diversity of Wtk1 is 9.5 times lower than that of broad-spectrum partial resistance gene Yr36 (π = 0.00019), and both are in sharp contrast to the high level of nucleotide diversity previously reported for race-specific resistance genes (e.g., Lr10 and Pm3). However, the nonfunctional wtk1 sequences possess high level of nucleotide diversity (π = 0.07). These results may reflect the different resistance mechanisms and the different evolutionary processes that shaped these resistance genes. Yr15 was absent in 189 Chinese wheat landraces and was present in only 1.02% of the 583 tested modern Chinese wheat cultivars. These results corroborate our previous results showing that Yr15 was absent in 94% of a worldwide collection of 513 wheat cultivars, therefore indicating the importance of Yr15 in wheat stripe rust resistance breeding programs in China and elsewhere around the globe.

Original languageEnglish
Article number212
JournalPathogens
Volume9
Issue number3
DOIs
StatePublished - 13 Mar 2020

Bibliographical note

Publisher Copyright:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Chinese wheat germplasm
  • Nucleotide diversity
  • Stripe rust resistance
  • Wild emmer populations
  • Yr15

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases
  • General Immunology and Microbiology
  • Molecular Biology
  • Immunology and Allergy

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