Mapping a leaf rust resistance gene in durum wheat Ofanto and its suppressor in common wheat.

Epidemics of leaf rust (caused by the fungal pathogen Erikss., ) raise concerns regarding sustainability of wheat production. Deployment of resistant cultivars is the most effective and economic strategy for combating this disease. Ofanto is a durum wheat cultivar that exhibits high resistance to race PHT throughout its entire growing period. In the present study, we identified a leaf rust resistance gene in Ofanto and temporarily designated it as . was mapped to a 2.5 cM genetic interval in chromosome arm 6BL between Indel markers and . During introgression of from Ofanto to common wheat it was observed that F plants of Ofanto crossed with Shi4185 exhibited leaf rust resistance whereas the F of Ofanto crossed with ND4503 was susceptible. In order to map the presumed suppressor locus, a Shi4185/ND4503//Ofanto three-way pentaploid population was generated and was mapped on chromosome arm 2AS. was mapped within a 2.6 cM genetic interval flanked by and . Fine mapping using 2,268 plants of the three-way cross narrowed the suppressor locus to a 68.2-kbp physical interval according to IWGSC RefSeq v1.1. Sequence analysis of genes in the physical interval revealed that encoding an RPP-13-like protein with an NB-ARC domain was a potential candidate for .