Broad-Spectrum Resistance to Leaf Rust in the Argentinean Wheat Cultivar “Klein Proteo” Is Controlled by LrKP Located on Chromosome 2BS

Abstract

Wheat leaf rust, caused by Puccinia triticina, is a severe fungal disease threatening global wheat production. The rational application of genetic loci controlling wheat resistance to leaf rust in breeding practice is still the best choice for disease control. A previous study indicated that the Argentinean wheat cultivar “Klein Proteo” might carry leaf rust resistance (Lr) genes Lr3a and Lr10, as well as an unknown Lr gene. In this study, seedlings of “Klein Proteo” showed high resistance to all the 20 Pt pathotypes isolated in China. Using bulked segregant RNA sequencing (BSR-seq) and developed CAPS markers, the single-dominant gene LrKP was initially mapped to a 114–168 Mb region on chromosome 2BS. Using gene-specific primers of a previously cloned chromosome 2BS-located Lr13 gene, we found that “Klein Proteo” also carried the Lr13 gene. Moreover, the expression of Lr13 in the resistant bulk was significantly higher than that in the susceptible bulk. Nevertheless, “Klein Proteo” showed a much broader and higher resistance compared with the near isogenic line and “ZhouMai 22” carrying Lr13. In conclusion, the wheat cultivar “Klein Proteo” showed great potential in the genetic improvement of wheat resistance to leaf rust in China and the genetic bases controlling the broad-spectrum resistance were initially revealed.