Puccinia graminis causes stem rust, a serious disease of cereals and forage grasses. Important formae speciales of P. graminis and their typical hosts are P. graminis f. sp. tritici (Pg-tr) in wheat and barley, P. graminis f. sp. lolii (Pg-lo) in perennial ryegrass and tall fescue, and P. graminis f. sp. phlei-pratensis (Pg-pp) in timothy grass. Brachypodium distachyon is an emerging genetic mo...

Race TTKSK (Ug99) of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici) is a serious threat to both wheat and barley production worldwide because of its wide virulence on many cultivars and rapid spread from eastern Africa. Line Q21861 is one of the most resistant barleys known to this race. To elucidate the genetics of resistance in this line, we evaluated the Q21861/SM89010 (Q/SM...

Sequence tagged site (STS) markers have been developed recently to identify resistance genes in wheat. A number of wild relatives have been used to transfer resistance genes into wheat cultivars. Accessions of wild species of Triticeae: Aegilops longissima (4), Ae. speltoides (6), Ae. tauschii (8), Ae. umbellulata (3), Ae. ventricosa (3), Triticum spelta (2), T. timopheevi (3), T. boeoticum (4)...

The genome size of the pine fusiform rust pathogen Cronartium quercuum f.sp. fusiforme (Cqf) was determined by flow cytometric analysis of propidium iodide-stained, intact haploid pycniospores with haploid spores of two genetically well characterized fungal species, Sclerotinia sclerotiorum and Puccinia graminis f.sp. tritici, as size standards. The Cqf haploid genome was estimated at ~90 Mb, s...

In plants, disease resistance mediated by the gene-for-gene mechanism involves the recognition of specific effector molecules produced by the pathogen either directly or indirectly by the resistance-gene products. This recognition triggers a series of signals, thereby serving as a molecular switch in regulating defense mechanisms by the plants. To understand the mechanism of action of the barle...

Rusts are one of the most severe threats to cereal crops because new pathogen races emerge regularly, resulting in infestations that lead to large yield losses. In 1999, a new race of stem rust, Puccinia graminis f. sp. tritici (Pgt TTKSK or Ug99), was discovered in Uganda. Most of the wheat and barley cultivars grown currently worldwide are susceptible to this new race. Pgt TTKSK has already s...

Race-specific resistance genes protect the global wheat crop from stem rust disease caused by Puccinia graminis f. sp. tritici (Pgt) but are often overcome owing to evolution of new virulent races of the pathogen. To understand virulence evolution in Pgt, we identified the protein ligand (AvrSr50) recognized by the Sr50 resistance protein. A spontaneous mutant of Pgt virulent to Sr50 contained ...

WANNER, R., FBRSTER, H., MENDGEN, K., AND STAPLES, R. C. 1985. Synthesis ofdifferentiation-specific proteins in germlings of the wheat stem rust fungus after heat shock. Experimental Mycology 9, 279-283. When uredospore germlings of the wheat stem rust fungus (Puccinia graminis tritici) were heat-shocked to induce differentiation, changes in the pattern of proteins synthesized were observed whe...

Fungal root endophytes obtained from natural vegetation were tested for antifungal activity in dual culture tests against the root pathogen Gaeumannomyces graminis var. tritici. Fifteen isolates, including Acremonium blochii, Acremonium furcatum, Aspergillus fumigatus, Cylindrocarpon sp., Cylindrocarpon destructans, Dactylaria sp., Fusarium equiseti, Phoma herbarum, Phoma leveillei, and a steri...