Lack of the barley (Hordeum vulgare) seven-transmembrane domain MLO protein confers resistance against the fungal pathogen Blumeria graminis f. sp. hordei (Bgh). To broaden the basis for MLO structure/function studies, we sequenced additional mlo resistance alleles, two of which confer only partial resistance. Wild-type MLO dampens the cell wall-restricted hydrogen peroxide burst at points of a...

MORC1 and MORC2, two of the seven members of the Arabidopsis (Arabidopsis thaliana) Compromised Recognition of Turnip CrinkleVirus1 subfamily ofmicrorchidiaGyrase,Heat ShockProtein90,HistidineKinase,MutL (GHKL)ATPases,were previously shown to be required in multiple layers of plant immunity. Here, we show that the barley (Hordeum vulgare) MORCs also are involved in disease resistance. Genome-wi...

Powdery mildew fungi are parasites that cause disease on a wide range of important crops. Plant resistance (R) genes, which induce host defences against powdery mildews, encode proteins that recognise avirulence (AVR) molecules from the parasite in a gene-for-gene manner. To gain insight into how virulence evolves in Blumeria graminis f.sp. hordei, associations between segregating AVR genes wer...

Increases in two extracellular peroxidases were observed following inoculation of barley (Hordeum vulgare L.) with the powdery mildew pathogen (Erysiphe graminis DC.: Fr. f. sp. hordei Em. Marchal). The more prominent isozyme, P8.5, was purified from intercellular wash fluids by acetone precipitation, ion-exchange chromatography, isoelectric focusing, and gel filtration. Purified P8.5 is a heme...

Introgressive hybridization has played a crucial role in crop breeding. Powdery mildew-resistant gene 21 (Pm21), located on the short arm of chromosome 6V of Haynaldia villosa (H. villosa), is typically a representative element which is transferred to hexaploid wheat through introgressive hybridization. Determination of sequence evidence for H. villosa DNA introgression would help trace Pm21 in...

Podosphaera (Sphaerotheca) euphorbiae on Euphorbia epithymoides (= E. polychroma, cushion spurge) is reported for the first time in North America. Neoerysiphe (Erysiphe) galeopsidis on Lamium amplexicaule (henbit), Blumeria (Erysiphe) graminis on Festuca idahoenis (Idaho fescue), Taphrina johansonii on Populus tremuloides (trembling aspen), and Taphrina occidentalis on Alnus rubra (red alder) a...