Les J. Szabo

Learn More
Rust fungi are some of the most devastating pathogens of crop plants. They are obligate biotrophs, which extract nutrients only from living plant tissues and cannot grow apart from their hosts. Their lifestyle has slowed the dissection of molecular mechanisms underlying host invasion and avoidance or suppression of plant innate immunity. We sequenced the(More)
UNLABELLED SUMMARY Stem rust has been a serious disease of wheat, barley, oat and rye, as well as various important grasses including timothy, tall fescue and perennial ryegrass. The stem rust fungus, Puccinia graminis, is functionally an obligate biotroph. Although the fungus can be cultured with difficulty on artificial media, cultures grow slowly and(More)
ABSTRACT Puccinia spp. are widespread pathogens of cereals and grasses that annually cause significant yield losses worldwide, especially in barley, oat, and wheat. Urediniospore morphology and early symptom development have limited usefulness for distinguishing Puccinia spp. Therefore, we developed real-time polymerase chain reaction assays for rapid(More)
Rust fungi are obligate biotrophic pathogens that cause considerable damage on crop plants. Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, and Melampsora larici-populina, the poplar leaf rust pathogen, have strong deleterious impacts on wheat and poplar wood production, respectively. Filamentous pathogens such as rust fungi secrete(More)
We developed an evolutionary relevant model system, barley-Puccinia [corrected] rust fungi, to study the inheritance and specificity of plant factors that determine to what extent innate nonhost immunity can be suppressed. A mapping population was developed from a cross between an experimental barley line (SusPtrit) [corrected] with exceptional(More)
In this study we provide a phylogenetically based introduction to the classes and orders of Pucciniomycotina (= Urediniomycetes), one of three subphyla of Basidiomycota. More than 8000 species of Pucciniomycotina have been described including putative saprotrophs and parasites of plants, animals and fungi. The overwhelming majority of these (approximately(More)
The life history of Puccinia striiformis remains a mystery because the alternate host has never been identified. Inoculation of grasses using aeciospores from naturally infected Berberis chinensis and B. koreana resulted in infection on Poa pratensis, producing uredinia typical of stripe rust caused by P. striiformis. Analyses using real-time polymerase(More)
Four cDNA clones (corresponding to tlp-1, -2, -3, and -4 genes) encoding thaumatin-like (TL), pathogenesis-related proteins were isolated from oat (Avena sativa) infected by an incompatible isolate Pga-1H of the oat stem rust fungus (Puccinia graminis f. sp. avenae). All four cDNA clones contained an open reading frame predicted to encode a 169-amino acid(More)
ABSTRACT In the late 1990s, commercial garlic fields in California (CA) were devastated by an outbreak of rust caused by Puccinia allii. We compared collections of the pathogen from garlic (Allium sativum) and chives (A. schoenoprasum) in central CA and Oregon (OR) to collections from garlic and leek (A. porrum and A. ampeloprasum) in the Middle East.(More)
Race Ug99 (TTKSK) of Puccinia graminis f. sp. tritici, detected in Uganda in 1998, has been recognized as a serious threat to food security because it possesses combined virulence to a large number of resistance genes found in current widely grown wheat (Triticum aestivum) varieties and germplasm, leading to its potential for rapid spread and evolution.(More)