- Li, Yinghui;
- Wei, Zhen-Zhen;
- Sela, Hanan;
- Govta, Liubov;
- Klymiuk, Valentyna;
- Roychowdhury, Rajib;
- Chawla, Harmeet Singh;
- Ens, Jennifer;
- Wiebe, Krystalee;
- Bocharova, Valeria;
- Ben-David, Roi;
- Pawar, Prerna B;
- Zhang, Yuqi;
- Jaiwar, Samidha;
- Molnár, István;
- Doležel, Jaroslav;
- Coaker, Gitta;
- Pozniak, Curtis J;
- Fahima, Tzion
Gene cloning in repeat-rich polyploid genomes remains challenging. Here, we describe a strategy for overcoming major bottlenecks in cloning of the powdery mildew resistance gene (R-gene) Pm69 derived from tetraploid wild emmer wheat. A conventional positional cloning approach was not effective owing to suppressed recombination. Chromosome sorting was compromised by insufficient purity. A Pm69 physical map, constructed by assembling Oxford Nanopore Technology (ONT) long-read genome sequences, revealed a rapidly evolving nucleotide-binding leucine-rich repeat (NLR) R-gene cluster with structural variations. A single candidate NLR was identified by anchoring RNA sequencing reads from susceptible mutants to ONT contigs and was validated by virus-induced gene silencing. Pm69 is likely a newly evolved NLR and was discovered in only one location across the wild emmer wheat distribution range in Israel. Pm69 was successfully introgressed into cultivated wheat, and a diagnostic molecular marker was used to accelerate its deployment and pyramiding with other R-genes.