Abstract
Leaf rust is a foliar disease caused by the fungus Puccinia triticina that may severely reduce durum wheat yield. Resistance to this pathogen is common in modern durum germplasm but is frequently based on Lr72 and Lr14a. After accounts of races with virulence to Lr14a gene in France in 2000, the present study reports the detection in 2013 for the first time of a new race with virulence to Lr14a and Lr72. The aim of this work was to characterize the virulence pattern of four Spanish isolates with virulence to Lr14a, and to discuss the consequences of this presence. Rusted leaves from cultivars ‘Don Jaime’ (Lr14a) and ‘Gallareta’ (Lr72) were collected in 2013 in the field at two Spanish sites, one in the south (near Cadiz) and another in the north (near Girona). Spores from single pustule for each cultivar and site were multiplied on susceptible cultivar ‘Don Rafael’. Then, the four isolates were inoculated on a set of 19 isogenic lines Thatcher to characterize their virulence spectrum. All isolates presented the same virulence pattern. They were virulent on both Lr14a and Lr72 and the race was named DBB/BS. This race was very similar to those reported in 2009-11, but with added virulence to Lr14a. The resistance based on Lr14a has therefore been overcome in Spain, by a new race that has likely emerged via stepwise mutation from the local predominating races. This information is important to guide breeders in their breeding programmes and gene deployment strategies.
Highlights
Durum wheat (Triticum turgidum subsp. durum) is an important crop in the Mediterranean basin
After accounts of races with virulence to Lr14a gene in France in 2000, the present study reports the detection in 2013 for the first time of a new race with virulence to Lr14a and Lr72
For more than three decades, the leaf rust resistance gene Lr14a has been effective in protecting durum wheat against leaf rust in Spain The presence of this commonly occurring gene in durum wheat germplasm was first reported by Herrera-Foessel et al (2008), who found two closely linked SSR (Single Sequence Repeats) markers
Summary
Durum wheat (Triticum turgidum subsp. durum) is an important crop in the Mediterranean basin. Durum) is an important crop in the Mediterranean basin. One of the most important biotic constraints affecting this crop is leaf rust, caused by the fungus Puccinia triticina. The Lr14a gene is located on chromosome arm 7BL and was originally transferred from the emmer wheat ‘Yaroslav’ to common wheat, and from there to durum wheat. Many cultivars resistant to leaf rust are known to carry Lr14a, such as ‘Creso’, an Italian cultivar first released in 1974, its descendant ‘Colosseo’ (Maccaferri et al, 2010), and some CIMMYT derived cultivars like ‘Don Jaime’ (Soleiman et al, 2014a). All have been resistant to the prevailing leaf rust races in Spain until 2011 (Soleiman, 2013)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
