Stripe Rust Resistance in Aegilops tauschii Germplasm

Abstract

Aegilops tauschii Coss., the D‐genome progenitor of hexaploid wheat (Triticum aestivum L.), is an important source of useful genes for wheat improvement. We characterized a germplasm collection of 118 Ae. tauschii accessions for response to stripe rust, a devastating disease caused by the fungus Puccinia striiformis f. sp. tritici (Pst). We evaluated tillering stage and adult‐plant resistance to stripe rust using prevalent Pst races from the United States and China. Resistant accessions predominated in Ae. tauschii subsp. strangulata and Ae. tauschii subsp. tauschii from the Caspian Sea region. We further analyzed the inheritance of stripe rust resistance by inoculating F2 plants of 60 crosses with a mixture of Chinese Pst races. Crosses between resistant and susceptible lines indicated both dominant and recessive inheritance. Tests of allelism among 14 highly resistant accessions indicated the common presence of YrAS2388, previously mapped on chromosome arm 4DS, in all accessions. In conclusion, the study presented valuable data on stripe rust resistance in Ae. tauschii, which assist with informed introgression of the D‐genome trait for stripe rust resistance in common wheat.

An ancestral NB-LRR with duplicated 3′UTRs confers stripe rust resistance in wheat and barley

“…The diverse Ae. tauschii D genome offers a valuable gene pool for stripe rust resistance 20,22 . To date, several stripe rust resistance genes have been mapped in Ae.…”

Molecular genetic characterisation of triple rust resistance in Aegilops tauschii

“…In our study, the stripe rust resistance gene Yr672 mapped to the short arm of chromosome 4D, where YrAS2388 / Yr28 were positioned earlier (Singh et al 2000;Huang et al 2011;Liu et al 2013 and Lr41 are allelic and linked closely to the SSR marker Xgdm35 (Singh et al 2004;Thind et al 2017). Through 90K SNP analysis, we identified tightly linked markers that are much closer to the gene than marker Xgdm35 reported earlier (Figure 3.2).…”

“…tauschii created a bottleneck in the genetic diversity of bread wheat (Rasheed et al 2018). In recent years, the germplasm of wild relatives were widely exploited to enrich the rust resistance gene pools for commercial breeding (Rouse et al 2011a;Liu et al 2013;Kalia et al 2017). Direct recombination between chromosome segments of wheat and its wild relatives encouraged breeders to facilitate artificial hybridisation for introgression of novel genes for genetic diversity Despite the availability of high-quality reference genome sequences, genetic information to unveil unique traits that are present only in old landraces and wild relatives are insufficient.…”

“…Therefore, the emergence of new races of stripe rust threaten wheat cultivation in Australia through exotic introductions, as demonstrated by the previous incidences. Detection of a stripe rust race in 2011 in Europe that has overcome the predominant winter wheat cultivar "Warrior" poses a serious threat on a global scale due to its tolerance of warm temperatures (Hubbard et al 2015;Hovmoller et al 2017 (Liu et al 2013). Accessions of Ae.…”

“…strangulata hold better resistance than ssp. tauschii accessions (Liu et al 2013). Two stripe rust resistance genes, Yr28 (accession WX219) and YrAs2388…”