Abstract
BackgroundPowdery mildew of barley is a wind-borne and obligate biotrophic pathogen, which ranks among the most widespread barley pathogens worldwide. However, purposeful research towards studying the structure of the barley powdery mildew populations, of their virulence and of effectiveness of certain resistance genes against the infection was not conducted in Kazakhstan till present time. This paper is the first to describe characteristics of the pathotype structure of Blumeria graminis f.sp. hordei (Bgh) population and effectiveness of resistance genes in two regions of barley cultivation in the republic.ResultsOne hundred and seven isolates of Bgh were obtained from seven populations occurring on cultivated barley at two geographically locations in Kazakhstan during 2015 and 2016. Their virulence frequency was determined on 17 differential lines Pallas. All isolates were virulent on the resistance gene Mla8 and avirulent for the resistance genes Mla9, Mla1 + MlaAl2, Mla6 + Mla14, Mla13 + MlRu3, Mla7 + MlNo3, Mla10 + MlDu2, Mla13 + MlRu3 and Mlo-5. The frequencies of isolates overcoming the genes Mla3, Mla22, Mlat Mlg + MlCP and Mla12 + MlEm2 were 0.0–33.33%, and frequencies of isolates overcoming the genes Mlra, Mlk, MlLa and Mlh ranged from 10.0 to 78.6%. Based on reactions of differential lines possessing the genes Mla22, Mlra, Mlk, Mlat, MlLa and Mlh, pathotypes were identified. In total, 23 pathotypes with virulence complexity ranging from 1 to 6 were identified. During both years in all populations of South Kazakhstan and Zhambyl regions pathotypes 24 and 64 mainly prevailed.ConclusionsObtained data suggest that low similarity of populations Bgh in Kazakhstan to European, African, Australian and South-East Asian populations. The present study provides a foundation for future studies on the pathogenic variability within of Bgh populations in Kazakhstan and addresses the knowledge gap on the virulence structure of Bgh in Central Asia. Complete effectiveness of the resistance genes, for which no corresponding virulence was found, will allow Kazakhstanean breeders to access many modern barley cultivars that those possessing the resistance effectiveness genes.
Highlights
Powdery mildew of barley is a wind-borne and obligate biotrophic pathogen, which ranks among the most widespread barley pathogens worldwide
The present study provides a foundation for future studies on the pathogenic variability within of Blumeria graminis f.sp. hordei (Bgh) populations in Kazakhstan and addresses the knowledge gap on the virulence structure of Bgh in Central Asia
Differentiation of Kazakhstani barley powdery mildew population resulted in isolation and propagation of 23 pathotypes with different virulence to isogenic Pallas lines
Summary
Powdery mildew of barley is a wind-borne and obligate biotrophic pathogen, which ranks among the most widespread barley pathogens worldwide. Purposeful research towards studying the structure of the barley powdery mildew populations, of their virulence and of effectiveness of certain resistance genes against the infection was not conducted in Kazakhstan till present time. Hordei (Bgh) population and effectiveness of resistance genes in two regions of barley cultivation in the republic. Spring two-rowed barley represents over 90% of all barleys in the country [6]. Such a low output can be explained by strong pressure from abiotic factors, such as drought, heat, and heavy rains in autumn, and by periodic invasions of devastating barley pathogens [7]. The pathogen affects crops of winter and spring barley in Kazakhstan. Finding effective and durable control measures to constrain powdery mildew fungi represents an important challenge in crop protection research
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