Nejvíce citovaný článek - PubMed ID 30958099
Functional Variation of Plant-Pathogen Interactions: New Concept and Methods for Virulence Data Analyses
Barley is an important crop grown on almost 49 Mha worldwide in 2021 and is particularly significant in Europe where powdery mildew is the most frequent disease on susceptible varieties. The most suitable way to protect crops is by exploiting genetic resistance. However, the causal agent Blumeria hordei is an extremely adaptable pathogen. The aims of this research were to increase our knowledge of the rapidly changing pathogen population and detect rare virulences. Random samples of the pathogen were obtained from the air by means of a mobile spore sampler. Spores were collected by driving across the Czech Republic in 2019, 2021 and 2023, and 299 isolates were analyzed on 121 host varieties. No infection occurred on 35 differentials, rare virulence was recorded on 31 varieties and a higher virulence frequency was found on 55 differentials. A core set of differentials along with four additional varieties distinguishes 295 pathotypes (Simple Index = 0.987) and the virulence complexity of isolates varied from 4 to 19 with an average of 10.39. The detection of new virulences, the increasing frequency of previously rare virulences and high pathotype diversity as well as high virulence complexity confirm that using nonspecific durable resistance is crucial for successfully breeding commercial varieties.
- Klíčová slova
- Blumeria graminis f. sp. hordei, Hordeum vulgare, barley, powdery mildew, resistance genes, reverse octal notation, virulence complexity, virulence frequency,
- Publikační typ
- časopisecké články MeSH
Plant research and breeding depends on plant genotypes; therefore, genotype authenticity of accessions is the basic requirement for users of gene banks. Surprisingly, this extremely important topic is rarely reported in the scientific community. Non-authentic are accessions that are mislabelled and undesirable genotypes of heterogeneous accessions. In barley, we try to uncover both named problems on the basis of postulated major powdery mildew resistance genes. These are diverse, environmentally stable and their use is well documented and suitable for genotype characterization. In this contribution, we postulate resistance genes in 15 varieties represented by 157 derived lines of 32 accessions originating from seven foreign gene banks and compare these findings with previous results including those 15 identically labelled varieties from our domestic gene bank. We found that 37.5% of the gene bank accessions investigated herein were heterogeneous, and at least 20.0% were mislabelled. A large-scale molecular characterisation of varieties is now being carried out, and using authentic varieties must be one of the key requirements. Therefore, accessions of each variety from a minimum of three gene banks whose identity has been verified by reliable methods should be compared before starting new experiments. These will involve molecular varietal characterisation to serve as a foundation for future plant science research and effective crop improvement.
Barley is an important crop grown annually on about 55 Mha and intensively cultivated in Europe. In central and north-western Europe, spring and winter barley can be grown in similar environments which creates suitable conditions for the development of barley pathogens, including Blumeria graminis f. sp. hordei, the causal agent of powdery mildew. Apart from pesticide application, it can be controlled by inexpensive and environmentally-friendly genetic resistance. In this contribution, results of the resistance gene identification in 58 barley cultivars to powdery mildew are presented. In 56 of them their resistances were postulated and in two hybrid cultivars a recently developed method of gene identification was used. In total, 18 known resistance genes were found and several unknown genes were detected. In spring barley, a gene of durable resistance mlo is still predominant. MlVe found in winter SU Celly was the only new resistance gene recorded in barley cultivars registered in the Czech Republic in this time span. Since 2001 eight new genes of specific resistance have been identified in cultivars registered in the country and their response under field conditions is discussed, including the corresponding responses of the pathogen population due to directional selection. Different strategies for breeding spring and winter barley are recommended.
- Klíčová slova
- Blumeria graminis f. sp. hordei, Hordeum vulgare, infection response arrays, pathogen isolates, resistance gene postulation,
- MeSH
- ječmen (rod) * genetika MeSH
- nemoci rostlin genetika MeSH
- šlechtění rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Evropa MeSH
Cultivation of resistant varieties is an environmentally friendly and inexpensive method of crop protection. Numerous alleles of specific disease resistance occur in cereals and other crops, and knowledge of their presence in individual varieties has wide utilization in research and practice. Postulation based on phenotyping host-pathogen interactions and the gene-for-gene model is a common way of identifying these genes. The same technique and design of tests are used for postulating virulence when pathogen populations are studied. Powdery mildews caused by different formae speciales of Blumeria graminis (Bg) are important cereal diseases. In this contribution, experimental methods are described that use a model organism Bg f. sp. hordei, which can be employed for other cereal mildews and possibly rusts. It includes illustrations and a summary of our long-term practical experience. It also critically evaluates the benefits of leaf segment tests compared with screening whole plants.
- Klíčová slova
- Blumeria graminis f. sp. hordei, Hordeum vulgare, barley powdery mildew, biotrophic pathogens, cereals, resistance gene postulation,
- Publikační typ
- časopisecké články MeSH
