Effect of three suppressors on the expression of powdery mildew resistance genes in barley

Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 492-498 ◽  
Author(s):  
J. Helms Jørgensen
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Infection Type ◽  
Phenotypic Expression ◽  
Mildew Resistance ◽  
Erysiphe Graminis Hordei ◽  
Key Words Barley ◽  
Additional Resistance ◽  
Infection Types

Three recessive mutagen-induced alleles that partially suppress the phenotypic expression of the semidominant powdery mildew resistance gene Mla12 have been studied. When each suppressor is present in homozygous condition, the infection type 0, conferred by gene Mla12 when homozygous, is changed to intermediate infection types. The three suppressor lines were crossed with seven near-isogenic lines with different powdery mildew resistance genes and one, M100, was crossed with nine additional lines. Seedlings of parents and from the F1and F2 generations were tested with powdery mildew isolates that possessed the appropriate avirulence and virulence genes. The segregation of phenotypes in the F2 generation disclosed that the three suppressors affected the phenotypic expression of three resistance genes, whereas that of four resistance genes remained unaffected. The suppressor in mutant M100 affected the phenotypic expression of 9 of the 10 additional resistance genes present. It is suggested that the three suppressors are mutationally modified genes involved in host defence processes. This implies that different resistance genes employ different, but overlapping, spectra of defence processes, or signal transduction pathways. Key words : barley, Hordeum vulgare, powdery mildew, Erysiphe graminis hordei, mutation, resistance, suppressor.

Genetic analysis of barley mutants with modifications of powdery mildew resistance gene Ml-a12

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 129-132 ◽  
Author(s):  
J. Helms Jørgensen
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Infection Type ◽  
Phenotypic Expression ◽  
Mutant Gene ◽  
Suppressor Gene ◽  
Susceptible Variety ◽  
Powdery Mildew Resistance Gene ◽  
Erysiphe Graminis Hordei ◽  
Infection Types

Fifteen mutants with increased powdery mildew susceptibility (infection types between 0–1 and 3–4) were crossed with the Ml-a12 resistant mother line 'Sultan-5' (infection type 0) and the susceptible variety 'Carlsberg II'. Analysis of the material revealed that 13 mutants had mutational modifications of the Ml-a12 gene. Two mutants had a suppressor-mutant gene that modified the phenotypic expression of gene Ml-a12. One suppressor gene was recessive, the other was semidominant. The possible function of gene Ml-a12 is discussed.Key words: barley, Hordeum vulgare, powdery mildew, Erysiphe graminis hordei, mutation, resistance, suppressor.

scholarly journals Strategies for RUN1 Deployment Using RUN2 and REN2 to Manage Grapevine Powdery Mildew Informed by Studies of Race Specificity

2015 ◽  
Vol 105 (8) ◽  
pp. 1104-1113 ◽  
Author(s):  
Angela Feechan ◽  
Marianna Kocsis ◽  
Summaira Riaz ◽  
Wei Zhang ◽  
David M. Gadoury ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Interleukin 1 ◽  
Resistance Locus ◽  
Mildew Resistance ◽  
Grapevine Powdery Mildew ◽  
Additional Resistance ◽  
Race Specificity

The Toll/interleukin-1 receptor nucleotide-binding site leucine-rich repeat gene, “resistance to Uncinula necator 1” (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic V. vinifera cultivars. However, sporulating powdery mildew colonies and cleistothecia of the heterothallic pathogen have been found on introgression lines containing the RUN1 locus growing in New York (NY). Two E. necator isolates collected from RUN1 vines were designated NY1-131 and NY1-137 and were used in this study to inform a strategy for durable RUN1 deployment. In order to achieve this, fitness parameters of NY1-131 and NY1-137 were quantified relative to powdery mildew isolates collected from V. rotundifolia and V. vinifera on vines containing alleles of the powdery mildew resistance genes RUN1, RUN2, or REN2. The results clearly demonstrate the race specificity of RUN1, RUN2, and REN2 resistance alleles, all of which exhibit programmed cell death (PCD)-mediated resistance. The NY1 isolates investigated were found to have an intermediate virulence on RUN1 vines, although this may be allele specific, while the Musc4 isolate collected from V. rotundifolia was virulent on all RUN1 vines. Another powdery mildew resistance locus, RUN2, was previously mapped in different V. rotundifolia genotypes, and two alleles (RUN2.1 and RUN2.2) were identified. The RUN2.1 allele was found to provide PCD-mediated resistance to both an NY1 isolate and Musc4. Importantly, REN2 vines were resistant to the NY1 isolates and RUN1REN2 vines combining both genes displayed additional resistance. Based on these results, RUN1-mediated resistance in grapevine may be enhanced by pyramiding with RUN2.1 or REN2; however, naturally occurring isolates in North America display some virulence on vines with these resistance genes. The characterization of additional resistance sources is needed to identify resistance gene combinations that will further enhance durability. For the resistance gene combinations currently available, we recommend using complementary management strategies, including fungicide application, to reduce populations of virulent isolates.

Modification of barley powdery mildew resistance gene Ml-a12 by induced mutation

1986 ◽  
Vol 28 (5) ◽  
pp. 725-731 ◽  
Author(s):  
J. Torp ◽  
J. Helms Jørgensen
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Powdery Mildew Resistance ◽  
Mutant Gene ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance ◽  
High Mutation Frequency ◽  
Erysiphe Graminis Hordei ◽  
Recessive Mutant ◽  
Infection Types

Kernels from a barley line, 'Sultan-5', with powdery mildew resistance gene Ml-a12 were treated with mutagens. Among 10 381 M1 spikes progeny tested with Ml-a12 avirulent powdery mildew, 25 segregated mutants with infection types between 0–1 n and 3–4cn. The resistance of the mutants is race specific in the sense that it is expressed only with powdery mildew cultures that are Ml-a12 avirulent but not with an Ml-a12 virulent culture. Genetic analysis of 10 mutants revealed that 9 had mutant genes that were allelic to gene Ml-a12, and one had a recessive mutant gene inherited independently of Ml-a12 on which it acted as a suppressor. The high mutation frequency in gene Ml-a12 and the gradual inhibition of the expression of gene Ml-a12, by mutation or suppression, strongly supports the suggestion that the gene function is associated with incompatibility rather than with compatibility.Key words: barley, Hordeum vulgare, powdery mildew, Erysiphe graminis hordei, mutation, resistance, suppressor.

Identification and SSR Mapping of Two Powdery Mildew Resistance Genes in Wild Emmer (Triticum dicoccoides) Accessions IW3 and IW10

2009 ◽  
Vol 35 (5) ◽  
pp. 761-767 ◽  
Author(s):  
Gen-Qiao LI ◽  
Ti-Lin FANG ◽  
Hong-Tao ZHANG ◽  
Chao-Jie XIE ◽  
Zuo-Min YANG ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Triticum Dicoccoides ◽  
Wild Emmer ◽  
Mildew Resistance

scholarly journals Virulence frequencies to powdery mildew resistance genes of winter barley cultivars

2010 ◽  
Vol 40 (No. 4) ◽  
pp. 135-140 ◽  
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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