Adaptation of Blumeria graminis f.sp. hordei to barley resistance genes in the Czech Republic in 1971&ndash;2000

Results of scoring the resistance of 35 selected spring barley varieties to powdery mildew, exhibiting high powdery mildew severity, in 307 variety trials of the Central Institute for Supervising and Testing in Agriculture were analysed. The varieties can be divided into two groups: the varieties that could not induce any changes in the pathogen population (the varieties with no effective resistance gene and varieties carrying gene mlo) and the varieties possessing major resistance genes [a total of 12 Ml-genes: a1, a3, a6, a7, a9, a12, a13, at, k1, La, g and (Kr)] to which the pathogen population adapted in 1971–2000. The time slope of decreasing resistance of varieties is described. The importance of individual evolutionary forces (mutations, migration, direct selection, indirect selection and recombinations) for the erosion of efficiency of respective major resistance genes and the effects of pathogen adaptation on population complexity and diversity are discussed.

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Virulence frequencies to powdery mildew resistance genes of winter barley cultivars

Plant Protection Science ◽

10.17221/466-pps ◽

2010 ◽

Vol 40 (No. 4) ◽

pp. 135-140 ◽

Cited By ~ 11

Author(s):

A. Dreiseitl

Keyword(s):

Czech Republic ◽

Powdery Mildew ◽

Resistance Genes ◽

Powdery Mildew Resistance ◽

Spring Barley ◽

Winter Barley ◽

The Czech Republic ◽

Mildew Resistance ◽

Barley Cultivars ◽

Random Samples

The virulence frequencies to powdery mildew resistance genes possessed by winter barley cultivars registered and newly tested in the Czech Republic were studied in 2000, 2002 and 2004. Random samples of the populations originating from winter and spring barley fields were obtained from the air by a mobile version of a jet spore sampler mounted on a car roof. Conidia were sampled by driving across the Czech Republic. Fourteen differentials, carrying 18 out of 20 currently identified resistance genes present in winter barley cultivars, were used. High virulence frequencies (85–100%) to most resistance genes were found. Lower virulence frequencies (14.1–40.1%) were found to only three resistance genes that have not been described yet; their preliminary designations are Ml(Va), Ml(Dt) and Ml(Ca). The importance of resistance of winter barley cultivars is discussed with respect to limiting the speed with which the pathogen adapts to genetic resistances possessed by commercial cultivars of both winter and spring barley, and to the necessity of lowering the costs for powdery mildew control in barley.

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Resistance of Spring Barley Varieties to Powdery Mildew in theCzechRepublicin 1971–2000

Czech Journal of Genetics and Plant Breeding ◽

10.17221/3718-cjgpb ◽

2011 ◽

Vol 39 (No. 2) ◽

pp. 31-44 ◽

Cited By ~ 2

Author(s):

A. Dreiseitl ◽

P. Pařízek

Keyword(s):

Molecular Markers ◽

Powdery Mildew ◽

Resistance Genes ◽

High Resistance ◽

Spring Barley ◽

Resistant Variety ◽

High Susceptibility ◽

Pathogen Population ◽

Major Resistance Gene ◽

Resistance Score

Resistance to powdery mildew of 127 spring barley varieties was evaluated in 702 official variety trials, using scores from 1 to 9. Trials with sufficient disease severity were only analysed. Varieties possessing the resistance genes Mla7 (Elgina), Ml(Kr) (BR-1519), Mla13 (Koral) and mlo (Forum) were among the most resistant ones. The varieties Diamant, HE-3527, HE-3631, II/61-FUDII and Zefir showed high susceptibility. Fifteen varieties, carrying the genes Mla1, Mla3, Mla6, Mla9, Mla13, Ml(Kr) and Ml(Sc), were in the first years of testing highly resistant, but became susceptible later. The score of the most resistant variety ranged each year from 8.05 to 9.00, only in 1987–1991 it was lower. Since the pathogen population rapidly adapted to most resistance genes in the mid eighties, no resistant variety was found in 1987–1989. From 1986 to 1995 on average only 6.6% of the tested varieties were resistant, but there was no variety with resistance score above 8.50. High resistance was typical for varieties possessing an effective major resistance gene. Since the resistance of such varieties was not durable, we recommend breeding of varieties with at least two fully effective resistance genes, using molecular markers.  

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Disease resistance and pathogen population genetic

Plant Protection Science ◽

10.17221/10375-pps ◽

2002 ◽

Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽

pp. 245-248

Author(s):

B.A. McDonald ◽

C. Linde

Keyword(s):

Resistance Gene ◽

Resistance Genes ◽

Durable Resistance ◽

Genetic Resistance ◽

Pathogen Population ◽

Evolutionary Forces ◽

Boom And Bust ◽

Major Resistance Genes ◽

Pathogen Populations ◽

Plant Pathosystems

Plant pathologists have seen many boom-and-bust cycles following the deployment of resistant varieties. These cycles result when pathogen populations adapt to the presence of a major resistance gene by evolving a new population that can overcome this resistance gene. The breakdown of genetic resistance is due to the evolution of the local pathogen population because of selection for mutants, recombinants, or immigrants that are better adapted to the resistant cultivar. To understand the process that leads to breakdown of a resistance gene, we need to understand the processes that govern pathogen evolution. Population geneticists have identified five evolutionary forces that interact to affect the evolution of organisms. We ranked these risks and developed a quantitative framework to predict the risk that a pathogen will evolve to overcome major resistance genes. Our hypothesis is that much of the durability of resistance genes is due to the nature of the pathogen population rather than to the nature of the resistance gene. The framework we developed can be used as a hypothesis to test against a large number of plant pathosystems. The underlying principles of the framework can be tested individually or in combination according to the available knowledge of the population genetics for any pathogen. We propose that this framework can be used to design breeding strategies to break the boom-and-bust cycle and lead to durable resistance.

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Virulence spectra determination in selected Blumeria graminis f. sp. hordei isolates

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201058050083 ◽

2010 ◽

Vol 58 (5) ◽

pp. 83-90

Author(s):

Antonín Dreiseitl ◽

Petra Adamcová

Keyword(s):

Czech Republic ◽

Powdery Mildew ◽

Resistance Genes ◽

Specific Resistance ◽

Pathogen Population ◽

The Czech Republic ◽

Barley Powdery Mildew ◽

Significant Step ◽

Complete Set ◽

Powdery Mildew Pathogen

Virulence spectra for 14 isolates of the barley powdery mildew pathogen considered to be added to the pathogen genebank were determined. The isolates were obtained from a sample of aerial pathogen population collected across the Czech Republic in 2009. The spectra were determined on 28 barley varieties, possessing mostly specific resistance genes and inoculated with the isolates examined. Based on differentiation among each other, all 14 isolates showed their originality. None of the isolates exhibited increased pathogenicity to a variety with the non-specific resistance gene mlo9. All isolates were virulent on varieties carrying specific resistance genes Mla8 and Mlra, and in contrast, none of the isolates was virulent on a variety with the gene Mla23 and with a combination of genes Mla3, MlaTu2. Required characters, such as virulence on the resistance Lv or avirulence on the gene Mlh, were confirmed in some isolates. The results represent a significant step toward obtaining a complete set of information about every isolate before its including in the working genebank of the pathogen.

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Emerging Blumeria graminis f. sp. hordei pathotypes reveal ‘Psaknon’ resistance in European barley varieties

The Journal of Agricultural Science ◽

10.1017/s0021859615001069 ◽

2015 ◽

Vol 154 (6) ◽

pp. 1082-1089 ◽

Cited By ~ 6

Author(s):

A. DREISEITL

Keyword(s):

Powdery Mildew ◽

Central Europe ◽

Powdery Mildew Resistance ◽

Quantitative Resistance ◽

Spring Barley ◽

Blumeria Graminis ◽

Winter Barley ◽

Cereal Crops ◽

Alternative Source ◽

The Czech Republic

SUMMARYBarley (Hordeum vulgare L.) is one of the most important cereal crops in the world and powdery mildew caused by the airborne fungus Blumeria graminis f. sp. hordei is a worldwide disease that causes frequent epidemics in Central and Northwestern Europe. Psaknon was one of first varieties in which powdery mildew resistance (Mlp1) was found, but no commercial variety with this resistance and no pathotype with the corresponding virulence have been recorded. In 2014, four isolates collected in the Czech Republic and virulent to Mlp1 were tested on 25 varieties and were also virulent to seven other resistances, including Venezia. These isolates revealed the presence of Mlp1 in six commercial spring and winter barley varieties from Southeastern and Central Europe and in six German winter barley candidate lines for registration in Czech variety trials. Based on the combined results of virulence and resistance, it was concluded that Vp1 is becoming a major factor contributing to increased virulence complexity and pathotype diversity in Central Europe. In breeding, employment of the non-specific resistance Mlo for spring barley and accumulation of quantitative resistance genes for winter barley can still be recommended in addition to exploiting a non-host resistance from an alternative source such as that present in Hordeum bulbosum.

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Effectiveness of major resistance genes and identification of new sources for disease resistance in wheat

Acta Agronomica Hungarica ◽

10.1556/aagr.59.2011.3.7 ◽

2011 ◽

Vol 59 (3) ◽

pp. 241-248 ◽

Cited By ~ 2

Author(s):

G. Vida ◽

M. Cséplő ◽

G. Gulyás ◽

I. Karsai ◽

T. Kiss ◽

...

Keyword(s):

Disease Resistance ◽

Powdery Mildew ◽

Leaf Rust ◽

Resistance Genes ◽

Rust Resistance ◽

Genetic Material ◽

Leaf Rust Resistance ◽

Wheat Varieties ◽

Major Resistance Genes ◽

Greenhouse Tests

Among the factors which determine yield reliability an important role is played by disease resistance. One of the breeding aims in the Martonvásár institute is to develop wheat varieties with resistance to major diseases. The winter wheat varieties bred in Martonvásár are examined in artificially inoculated nurseries and greenhouses for resistance to economically important pathogens. The effectiveness of designated genes for resistance to powdery mildew and leaf rust has been monitored over a period of several decades. None of the designated major resistance genes examined in greenhouse tests is able to provide complete resistance to powdery mildew; however, a number of leaf rust resistance genes provide full protection against pathogen attack (Lr9, Lr19, Lr24, Lr25, Lr28 and Lr35). In the course of marker-assisted selection, efficient resistance genes (Lr9, Lr24, Lr25 and Lr29) have been incorporated into Martonvásár wheat varieties. The presence of Lr1, Lr10, Lr26, Lr34 and Lr37 in the Martonvásár gene pool was identified using molecular markers. New sources carrying alien genetic material have been tested for powdery mildew and leaf rust resistance. Valuable Fusarium head blight resistance sources have been identified in populations of old Hungarian wheat varieties. Species causing leaf spots (Pyrenophora tritici-repentis, Septoria tritici and Stagonospora nodorum) have gradually become more frequent over the last two decades. Tests on the resistance of the host plant were begun in Martonvásár four years ago and regular greenhouse tests on seedlings have also been initiated.

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Specific Resistance of Barley to Powdery Mildew, Its Use and Beyond: A Concise Critical Review

Genes ◽

10.3390/genes11090971 ◽

2020 ◽

Vol 11 (9) ◽

pp. 971 ◽

Cited By ~ 2

Author(s):

Antonín Dreiseitl

Keyword(s):

Powdery Mildew ◽

Resistance Genes ◽

Plant Pathogens ◽

Specific Resistance ◽

Wide Spectrum ◽

Quantitative Resistance ◽

Spring Barley ◽

Durable Resistance ◽

Genetic Resistance ◽

Barley Cultivars

Powdery mildew caused by the airborne ascomycete fungus Blumeria graminis f. sp. hordei (Bgh) is one of most common diseases of barley (Hordeum vulgare). This, as with many other plant pathogens, can be efficiently controlled by inexpensive and environmentally-friendly genetic resistance. General requirements for resistance to the pathogens are effectiveness and durability. Resistance of barley to Bgh has been studied intensively, and this review describes recent research and summarizes the specific resistance genes found in barley varieties since the last conspectus. Bgh is extraordinarily adaptable, and some commonly recommended strategies for using genetic resistance, including pyramiding of specific genes, may not be effective because they can only contribute to a limited extent to obtain sufficient resistance durability of widely-grown cultivars. In spring barley, breeding the nonspecific mlo gene is a valuable source of durable resistance. Pyramiding of nonspecific quantitative resistance genes or using introgressions derived from bulbous barley (Hordeum bulbosum) are promising ways for breeding future winter barley cultivars. The utilization of a wide spectrum of nonhost resistances can also be adopted once practical methods have been developed.

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