RAR1 is a eukaryotic zinc-binding protein first identified as required for race-specific resistance to powdery mildew in barley. To study the function of TaRAR1 involvement in wheat (Triticum aestivum L.) defense against the infection of stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst), we identified and cloned three wheat homeologous genes highly similar to the barley HvRar1, des...

The rust Puccinia andropogonis (Schwein.) was studied on its aecial and telial plant hosts, comandra (Comandra umbellata L. Nutt.) and big bluestem (Andropogon gerardii Vitman), respectively, in a native prairie to investigate the influence of aecial host proximity on disease severity of the telial host in a natural system. Both hosts were mapped to measure distances from comandra clones to sel...

The Neotropical rust fungus Puccinia psidii, notorious for the severity of its impacts and its broad host range in the family Myrtaceae, is believed to pose the greatest current threat to Hawaii’s forests, including Eucalyptus plantations. Multiple strains of this rust have demonstrated ability to infect different suites of host plants. Only one genotype established in Hawai'i in early 2005 and...

4 General introduction 6 Paper I. 13 Are environmental factors influencing the prevalence of rust in pathosystem Falcaria vulgaris– Pucinia sii-falcariae? Paper II. 29 Low effect of pathogen on population characteristics in pathosystem Falcaria vulgaris–Pucinia sii-falcariae: matrix model results Paper III. 57 Effect of systemic diseases on clonal integration: modelling approach

Damage or mortality from pathogens can reduce productivity of forest plantations, as well as significantly harm natural forest ecosystems. Genetic resistance within the host species is the first line of defense for tree species. Resistance breeding programs for the native fusiform rust and exotic (to North America) white pine blister rust diseases are two of the longest concerted efforts in for...

Virulence shifts in populations of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of Pst, necessitating the identification and introgression of new sources of resistance. Germplasm core collections that reflect the range of gene...

The barley stem rust resistance gene Reaction to Puccinia graminis 1 (Rpg1), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen Puccinia graminis f. sp. tritici. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inoculation, followed by hyphae and haustorium formation. The RPG1 protein is constitutively expressed an...

Analysis of DNA sequence variation among genotypes is useful for differentiation of wheat accessions, selection strategies and genetic development of crop plants. We screened molecular markers for yellow rust resistance genes (Yr7, Yr9, Yr15, Yr18, Yr26, and YrH52), which are in the gene-rich regions of wheat chromosomes 1B, 2B, and 7D, to investigate DNA sequence differences and repeat mo...

Stem rust is one of the most potentially harmful wheat diseases, but has been effectively controlled in China since 1970s. However, the interest in breeding wheat with durable resistance to stem rust has been renewed with the emergence of Ug99 (TTKSK) virulent to the widely used resistance gene Sr31, and by which the wheat stem rust was controlled for 40 years in wheat production area worldwide...