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United States Department of Agriculture

Agricultural Research Service

Research Project: CEREAL RUST FUNGI: GENETICS, POPULATION BIOLOGY, AND HOST-PATHOGEN INTERACTIONS

Location: Cereal Disease Laboratory

Title: Host status of barley to Puccinia coronata from couch grass and P. striiformis from wheat and brome

Authors
item Niks, Rients -
item Van Heyzen, Skye -
item Szabo, Les
item Alemu, Sisay -

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2013
Publication Date: June 1, 2013
Citation: Niks, R.E., Van Heyzen, S., Szabo, L.J., Alemu, S.K. 2013. Host status of barley to Puccinia coronata from couch grass and P. striiformis from wheat and brome. European Journal of Plant Pathology. 136(2):393-405.

Interpretive Summary: Rust fungi are economically important pathogens of cereals and grasses. Understanding the host range of these plant pathogens is important to better understand the epidemiology and develop appropriate control strategies. Field collections in Europe of two rust pathogens, Puccinia coronata and P. striiformis (causal agents of crown rust and stripe rust, respectively) were characterized. The P. coronata sample, collected from wild couch grass (Elytrigia repens) was pathogenic on seedling stage of most barley accessions tested, but not on adult plants. Morphological and DNA analysis determined that this rust fungus is P. coronata f. sp. hordei. The P. striiformis sample, collected from brome grass (Bromus carinatus) was pathogenic to approximately 50% of the barley lines tested at the seedling stage. This was intermediate between the P. striiformis f. sp. tritici (wheat type) and P. striiformis f. sp. hordei (barley type), indicating that P. striiformis collected from brome grass is a distinct type of the stripe rust pathogen. Other scientists studying cereal rust diseases will use this information.

Technical Abstract: The pathogenicity and identity of a field sample (PcE) of crown rust fungus Puccinia coronata collected in Hungary on wild couch grass (Elytrigia repens) and of a field sample (Psb) of stripe rust (P. striiformis) collected in the Netherlands on California brome (Bromus carinatus) was studied. We focused on the analysis of the host susceptibility of cultivated barley (Hordeum vulgare) to both pathogen samples, in direct comparison with an isolate of P. striiformis f.sp. tritici (Pst) and P. striiformis f.sp. hordei (Psh). At the seedling stage 83% of the barley accessions were susceptible to PcE. At the adult plant stage, cultivated barley was predominantly resistant to this crown rust sample. Morphology, pathogenicity on Hordeum and Bromus and ITS DNA sequence analysis determined that PcE represents a European specimen of P. coronata f.sp. hordei. Sample Psb was pathogenic on 47% of the cultivated barley at the seedling stage. This is intermediate between the isolates Psh (90%) and Pst (10%). Psb and Psh were pathogenic to grasses representing several genera. The host range of the Pst isolate was more narrow. We conclude that Psb is unlikely to represent a genotype of Psh that happened to have colonized B. carinatus, and is likely a distinct form of P. striiformis.

Last Modified: 12/17/2014
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