Showing papers on "Plant disease resistance published in 1994"

A Central Role of Salicylic Acid in Plant Disease Resistance

Abstract: Transgenic tobacco and Arabidopsis thaliana expressing the bacterial enzyme salicylate hydroxylase cannot accumulate salicylic acid (SA). This defect not only makes the plants unable to induce systemic acquired resistance, but also leads to increased susceptibility to viral, fungal, and bacterial pathogens. The enhanced susceptibility extends even to host-pathogen combinations that would normally result in genetic resistance. Therefore, SA accumulation is essential for expression of multiple modes of plant disease resistance.

RPS2 of Arabidopsis thaliana: a leucine-rich repeat class of plant disease resistance genes

Abstract: Plant disease resistance genes function is highly specific pathogen recognition pathways. PRS2 is a resistance gene of Arabidopsis thaliana that confers resistance against Pseudomonas syringae bacteria that express avirulence gene avrRpt2. RPS2 was isolated by the use of a positional cloning strategy. The derived amino acid sequence of RPS2 contains leucine-rich repeat, membrane-spanning, leucine zipper, and P loop domains. The function of the RPS2 gene product in defense signal transduction is postulated to involve nucleotide triphosphate binding and protein-protein interactions and may also involve the reception of an elicitor produced by the avirulent pathogen.

Active Oxygen Species in Plant Defense against Pathogens.

Abstract: Plant disease resistance to pathogens such as fungi, bacteria, and viruses often depends on whether the plant is able to recognize the pathogen early in the infection process. The recognition event leads to a rapid tissue necrosis at the site of infection, which is called the HR. The HR deprives the pathogen of nutrients and/or releases toxic molecules, thereby confining pathogen growth to a small region of the plant. This response provides resistance to the great majority of potential pathogens (nonhost or species resistance). For a given plant species, a much more limited number of true pathogens exhibit the ability to evade the host recognition system and grow extensively within the plant without evoking host necrosis at a11 or only after considerable delay. In this case, the plant exhibits susceptibility and the extensive growth of the successful pathogen can cause varying degrees of damage. However, certain races within pathogenic bacteria1 or funga1 species are recognized by certain cultivars or genotypes of the host plant species and the HR is triggered. These observations indicate that there is an ongqing evolution of the host plant's ability to recognize pathogen races that were previously unrecognized while the pathogen evolves to avoid recognition by a previously resistant host. Recognition of pathogens triggers a large range of inducible defense mechanisms that are believed to contribute to overall resistance in the plant. The mechanisms induced at the site of infection and associated with the HR include synthesis of antimicrobial compounds called phytoalexins, synthesis of hydrolytic enzymes that attack fungi and bacteria, and alterations in the synthesis of cell-wall structural proteins (for

RFLP mapping of genes conferring complete and partial resistance to blast in a durably resistant rice cultivar

Abstract: Moroberekan, a japonica rice cultivar with durable resistance to blast disease in Asia, was crossed to the highly susceptible indica cultivar, CO39, and 281 F7 recombinant inbred (RI) lines were produced by single seed descent. The population was evaluated for blast resistance in the greenhouse and the field, and was analyzed with 127 restriction fragment length polymorphism (RFLP) markers. Two dominant loci associated with qualitative resistance to five isolates of the fungus were tentatively named Pi-5(t) and Pi-7(t). They were mapped on chromosomes 4 and 11, respectively. To identify quantitative trait loci (QTLs) affecting partial resistance, RI lines were inoculated with isolate PO6-6 of Pyricularia oryzae in polycyclic tests. Ten chromosomal segments were found to be associated with effects on lesion number (P 6.0). Three of the markers associated with QTLs for partial resistance had been reported to be linked to complete blast resistance in previous studies. QTLs identified in greenhouse tests were good predictors of blast resistance at two field sites. This study illustrates the usefulness of RI lines for mapping a complex trait such as blast resistance and suggests that durable resistance in the traditional variety, Moroberekan, involves a complex of genes associated with both partial and complete resistance.

Enhanced Protection Against Fungal Attack by Constitutive Co–expression of Chitinase and Glucanase Genes in Transgenic Tobacco

Abstract: Plants respond to pathogen attack by the induction of a battery of defenses, suggesting that different protective mechanisms may have complementary roles in the overall expression of disease resistance. We have investigated possible functional interactions between two different hydrolytic enzymes, chitinase and glucanase, by constitutive co-expression in transgenic tobacco of genes encoding the rice RCH10 basic chitinase and the alfalfa AGLU1 acidic glucanase. Hybrid plants were generated by crossing transgenic parental lines exhibiting strong constitutive expression of cauliflower mosaic virus (CaMV) 35S enhancer / RCH10 and CaMV 35S double promoter / AGLU1 gene fusions, respectively. Evaluation of disease development in these hybrids, heterozygous for each transgene, and in homozygous selfed progeny, showed that combination of the two transgenes gave substantially greater protection against the fungal pathogen Cercospora nicotianae, causal agent of frogeye, than either transgene alone. Productive interactions between chitinase and glucanase transgenes in vivo point to combinatorial expression of antimicrobial genes as an effective approach to engineering enhanced crop protection against fungal disease.

A disease resistance gene in Arabidopsis with specificity for two different pathogen avirulence genes.

Abstract: The RPS3 and RPM1 disease resistance loci of Arabidopsis confer resistance to Pseudomonas syringae strains that carry the avirulence genes avrB and avrRpm1, respectively. We have previously shown that RPS3 and RPM1 are closely linked genetically. Here, we show that RPS3 and RPM1 are in fact the same gene. We screened a mutagenized Arabidopsis population with a P. syringae strain carrying avrB and found 12 susceptible mutants. All 12 mutants were also susceptible to an isogenic strain carrying avrRpm1, indicating a loss of both RPS3 and RPM1 functions. No mutants were recovered that lost only RPS3 function. Genetic analysis of four independent mutants revealed that the lesions were in RPS3. Thus, a single gene in Arabidopsis confers resistance that is specific to two distinct pathogen avirulence genes--a gene-for-genes interaction. This observation suggests that the RPS3/RPM1 gene product can bind multiple pathogen ligands, or alternatively, that it does not function as a receptor.

Biologically induced systemic acquired resistance in Arabidopsis thaliana

Abstract: Summary Local infection with a necrotizing pathogen can render plants resistant to subsequent infection by normally virulent pathogens. A system for biological induction of such systemic acquired resistance (SAR) in Arabidopsis thaliana is reported. When plants were immunized by local inoculation of a single leaf with avirulent Pseudomonas syringae pv. tomato (Pst) carrying the avrRpt2 avirulence gene, after 2 days other leaves became resistant, as measured symptomatically and by in planta bacterial growth, to challenge with a virulent Pst strain lacking this avirulence gene. Resistance was systemic and protected the plants against infection by other virulent pathogens including P. syringae pv. maculicola. Low-dose inoculation induced a strong SAR and double immunizations did not increase the level of protection indicating that the response of only a few cells to the immunizing bacteria is required. SAR was not induced by the virulent strain of Pst lacking avrRpt2. However, experiments with the Arabidopsis RPS2 disease resistance gene mutant rps2-201, which does not exhibit a local hypersensitive response to Pst carrying the corresponding avirulence gene avrRpt2, indicate that a hypersensitive response contributes to, but is not essential for, the induction of SAR. Thus, avrRpt2 activates either a branching signal pathway or separate parallel pathways for induction of localized hypersensitive resistance and SAR, with downstream potentiation of the systemic response by the local response. Using this system for the biological induction of SAR in Arabidopsis, it should be possible to dissect the molecular genetics of SAR by the isolation of mutants affected in the production, transmission, perception and transduction of the systemic signal(s).

Tomato mutants altered in bacterial disease resistance provide evidence for a new locus controlling pathogen recognition.

Abstract: We have employed a genetic approach to study the resistance of tomato to the phytopathogenic bacterium Pseudomonas syringae pv tomato. Resistance to P. s. tomato depends upon expression of the Pto locus in tomato, which encodes a protein with similarity to serine/threonine protein kinases and recognizes pathogen strains expressing the avirulence gene avrPto. Eleven tomato mutants were isolated with altered resistance to P. s. tomato strains expressing avrPto. We identified mutations both in the Pto resistance locus and in a new locus designated Prf (for Pseudomonas resistance and fenthion sensitivity). The genetic approach allowed us to dissect the roles of these loci in signal transduction in response to pathogen attack. Lines carrying mutations in the Pto locus vary 200-fold in the degree to which they are susceptible to P. s. tomato strains expressing avrPto. The pto mutants retain sensitivity to the organophosphate insecticide fenthion; this trait segregates with Pto in genetic crosses. This result suggested that contrary to previous hypotheses, the Pto locus controls pathogen recognition but not fenthion sensitivity. Interestingly, mutations in the prf locus result in both complete susceptibility to P. s. tomato and insensitivity to fenthion, suggesting that Prf plays a role in tomato signaling in response to both pathogen elicitors and fenthion. Because pto and prf mutations do not alter recognition of Xanthomonas campestris strains expressing avrBsP, an avirulence gene recognized by all tested tomato cultivars, Prf does not play a general role in disease resistance but possibly functions specifically in resistance against P. s. tomato. Genetic analysis of F2 populations from crosses of pto and prf homozygotes indicated that the Pto and Prf loci are tightly linked.

Differential protection against papaya ringspot virus isolates in coat protein gene transgenic papaya and classically cross-protected papaya.

Abstract: Transgenic papaya expressing the coat protein gene of the mild papaya ringspot virus strain from Hawaii (PRV HA 5-1) showed high levels of resistance against the severe PRV HA isolate from Hawaii. Inoculation with high concentrations of the virus, multiple mechanical inoculations, or graft inoculations failed to break the resistance of transgenic papaya. Virus recovery assays from these inoculated plants suggested that virus replication and movement were impaired. Transgenic papaya also showed high levels of resistance against severe PRV isolates recently collected from Hawaii. Similarly, PRV HA 5-1 cross-protected papaya offered high levels of protection against two of the three isolates from Hawaii

Transgenic tomato plants expressing the tomato yellow leaf curl virus capsid protein are resistant to the virus.

Abstract: The tomato yellow leaf curl virus (TYLCV) gene that encodes the capsid protein (V1) was placed under transcriptional control of the cauliflower mosaic virus 35S promoter and cloned into an Agrobacterium Ti-derived plasmid and used to transform plants from an interspecific tomato hybrid, Lycopersicon esculentum X L. pennellii (F1), sensitive to the TYLCV disease. When transgenic F1 plants, expressing the V1 gene, were inoculated with TYLCV using whiteflies fed on TYLCV-infected plants, they responded either as untransformed tomato or showed expression of delayed disease symptoms and recovery from the disease with increasingly more resistance upon repeated inoculation. Transformed plants that were as sensitive to inoculation as untransformed controls expressed the V1 gene at the RNA level only. All the transformed plants that recovered from disease expressed the TYLCV capsid protein.

Restriction fragment length polymorphism analysis of loci associated with disease resistance genes and developmental traits in Pisum sativum L.

Abstract: An F2 population of pea (Pisum sativum L.) consisting of 174 plants was analysed by restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) techniques. Ascochyta pisi race C resistance, plant height, flowering earliness and number of nodes were measured in order to map the genes responsible for their variation. We have constructed a partial linkage map including 3 morphological character genes, 4 disease resistance genes, 56 RFLP loci, 4 microsatellite loci and 2 RAPD loci. Molecular markers linked to each resistance gene were found: Fusarium wilt (6 cM from Fw), powdery mildew (11 cM from er) and pea common Mosaic virus (15 cM from mo). QTLs (quantitative traits loci) for Ascochyta pisi race C resistance were mapped, with most of the variation explained by only three chromosomal regions. The QTL with the largest effect, on chromosome 4, was also mapped using a qualitative, Mendelian approach. Another QTL displayed a transgressive segregation, i.e. the parental line that was susceptible to Ascochyta blight had a resistance allele at this QTL. Analysis of correlations between developmental traits in terms of QTL effects and positions suggested a common genetic control of the number of nodes and earliness, and a loose relationship between these traits and height.

Developmentally regulated cell death on expression of the fungal avirulence gene Avr9 in tomato seedlings carrying the disease-resistance gene Cf-9

Abstract: Plant defense responses are induced when the products of disease-resistance genes and pathogen avirulence genes interact We report here the effects of expressing the Cladosporium fulvum avirulence Avr9 gene product in a tomato line containing the Cf-9 disease-resistance gene A synthetic Avr9 gene was constructed to produce constitutive high-level expression of AVR9 peptide in the plant apoplast Avr9 expression in Cf-9-containing tomato lines is lethal, but cell death is developmentally regulated, in that necrosis is not visible until 10 days after planting seed Plant lines lacking Cf-9 and expressing Avr9 remain healthy The synthetic Avr9 gene exhibited the same specificity of action as the authentic C fulvum Avr9 gene Our results have significant implications for strategies using the gene combination Avr9/Cf-9 to engineer plants with enhanced disease resistance

Acquired Resistance in Barley (The Resistance Mechanism Induced by 2,6-Dichloroisonicotinic Acid Is a Phenocopy of a Genetically Based Mechanism Governing Race-Specific Powdery Mildew Resistance).

Abstract: Treatment of susceptible barley (Hordeum vulgare) seedlings with 2,6-dichloroisonicotinic acid (DCINA) induces disease resistance against the powdery mildew fungus (Erysiphe graminis f. sp. hordei). A cytological analysis of the interaction reveals the hypersensitive cell collapse in attacked, short epidermal cells, along with the accumulation of fluorescent material in papillae, that appear at the time of fungal arrest. The cell-type-specific hypersensitive reaction occurs prior to formation of haustoria, reminiscent of the mechanism identified in genetically resistant barley plants containing the functionally active Mlg gene (R. Gorg, K. Hollricher, P. Schulze-Lefert [1993] Plant J 3: 857-866). This observation indicates that the mechanism of DCINA-induced resistance is a phenocopy of the mechanism governed by the Mlg locus. The onset of acquired resistance correlates with high-level transcript accumulation of barley defense-related genes encoding pathogenesis-related protein-1, peroxidase, and chitinase but not [beta]-1,3-glucanase. Subcellular localization of peroxidase activity shows an increase in enzyme activity in the epidermal cell layer and in the intercellular fluids of barley leaves. Four out of more than 10 identified extracellular isozymes are induced by DCINA. The epidermal cell layer contains a major constitutively formed isozyme, together with two isozymes specifically induced by DCINA. The data support the hypothesis that host cell death and high-level accumulation of defense-related gene transcripts are not only commonly controlled in certain types of race-specific resistance (A. Freialdenhoven, B. Scherag, K. Hollricher, D.B. Collinge, H. Thordal-Christensen, P. Schulze-Lefert [1994] Plant Cell 6: 983-994) but also in acquired resistance, which confers protection to a broad spectrum of different pathogens.

Cytogenetically monitored transfer of powdery mildew resistance from rye into wheat.

Abstract: Powdery mildew, caused by the fungus Erysiphe graminis DC. ex Merat f. sp. tritici Em. Marchal, is a serious disease of cultivated bread wheat, Triticum aestivum L. em Thell. About 10 powdery mildew resistance genes are known in wheat and most of them are used in cultivar improvement. However, many of these genes were overcome by the fungus and are no longer effective and therefore, new sources of resistance are continuously being sought. Recently, we reported a new source of powdery mildew resistance, preliminarily designated MIP6L, that was derived from the long arm of chromosome 6R of Secale cereale L. cv. Prolific. The aim of this study was to transfer MIP6L to a cytologically stable wheat-rye chromosome translocation [...]

Intergeneric transfer (rye to wheat) of a gene(s) for Russian wheat aphid resistance

Abstract: An octoploid triticale was derived from the F 1 of a Russian wheat aphid-resistant rye, «Turkey 77», and «Chinese Spring» wheat. The alloploid was crossed to common wheat, and to «Imperial» rye/«Chinese Spring» disomic addition lines. F 2 progeny from these crosses were tested for Russian wheat aphid resistance and C-banded. A resistance gene(s) was found to be associated with chromosome arm 1RS of the «Turkey 77» rye genome. A monotelosomic 1RS («Turkey 77») addition plant was then crossed with the wheat cultivar «Gamtoos», which has the 1BL.1RS «Veery» translocation. Unlike the 1RS segment in «Gamtoos», the «Turkey 77»-derived 1RS telosome did not express the rust resistance genes Sr31 and Lr26, which could then be used as markers. From the F 1 a monotelosomic 1RS addition plant that was also heterozygous for the 1BL.1RS translocation was selected and testcrossed with an aphid-susceptible common wheat, «Inia 66». Meiotic pairing between the rye arms resulted in the recovery of five euploid Russian-wheat-aphid-resistant plants. One recombinant also retained Sr31 and Lr26 and was selfed to produce translocation homozygotes

Accumulation and translocation of tomato yellow leaf curl virus (TYLCV) in a Lycopersicon esculentum breeding line containing the L. chilense TYLCV tolerance gene Ty-1.

Abstract: The major tomato yellow leaf curl virus (TYLCV) tolerance gene, Ty-1, of the wild tomato species Lycopersicon chilense was mapped to chromosome 6 by using restriction fragment length polymorphism (RFLP) markers and introgressed into the domesticated tomato L. esculentum. Two nearly isogenic breeding lines were obtained. In infected fields, plants from line 32, which contained the Ty-1 allele, remained symptomless (tolerant line); plants from line 30, which did not contain the Ty-1 allele, were all symptomatic (susceptible line). The effect of the Ty-1 gene on TYLCV DNA accumulation and translocation was investigated by hybridizing plant DNA extracts with a viral DNA probe

Inheritance of black sigatoka disease resistance in plantain-banana (Musa spp.) hybrids.

Abstract: Black sigatoka (Mycosphaerella fijiensis Morelet), an airborne fungal leaf-spot disease, is a major constraint to plantain and banana (Musa spp.) production world-wide. Gaining further knowledge of the genetics of host-plant resistance will enhance the development of resistant cultivars, which is considered to be the most appropriate means to achieve stable production. Genetic analysis was conducted on 101 euploid (2x, 3x and 4x) progenies, obtained from crossing two susceptible triploid plantain cultivars with the resistant wild diploid banana ‘Calcutta 4’. Segregating progenies, and a susceptible reference plantain cultivar, were evaluated over 2 consecutive years. Three distinct levels of host response to black sigatoka were defined as follows: susceptible ( 10). Segregation ratios for resistance at the 2x level fitted a genetic model having one major recessive resistance allele (bs1) and two independent alleles with additive effects (bsr2 and bsr3). A similar model explains the results at the 4x level assuming that the favourable resistance alleles have a dosage effect when four copies of them are present in their respective loci (bsi4). The proposed model was further validated by segregation data of S1 progenies. Mechanisms of black sigatoka resistance are discussed in relation to the genetic model.

Practices and perspective of control of papaya ringspot virus by cross protection

Abstract: Papaya (Carica papaya L.) is widely grown in tropical and subtropical areas for its edible fruit and delicate taste. The plant grows fast and the fruit can be harvested 8–10 months after transplanting the tree in the field. It continues producing fruit for 2–3 years under normal conditions. The delicious and nutritious fruit contains a popular protease, papain, which helps to digest food for assimilation. The extensive adaption of this plant and wide acceptance of the fruit offer considerable promise for papaya as a commercial crop for local and export purpose. Like banana, pineapple, and mango, papaya is one of the important cash crops in the tropics and subtropics.

Characteristics of a resistance-breaking isolate of potato virus Y causing potato tuber necrotic ringspot disease.

Abstract: An Austrian isolate of potato virus YNTN, the causal agent of potato tuber necrotic ringspot disease (PTNRD), was serologically compared with seven Dutch PVYN isolates. Using polyclonal and monoclonal antibodies, it was found indistinguishable from PVYN. Determination of the nucleotide sequence of the coat protein cistron and comparison of the deduced amino acid sequence with coat protein sequences of other potyviruses revealed a high level of homology with PVYN coat protein sequences. This confirmed the close taxonomic relationship of PVYNTN with the PVYN subgroup of potato virus Y. PVYNTN is able to overcome all resistance genes known so far in commercial potato cultivars. Remarkably, transgenic PVY-protected tobacco plants are also resistant to PVYNTN infection upon mechanical and aphid-mediated inoculation. These experiments indicate that genetically engineered resistance offers great potential in protection of potato to new aggressive strains of PVYN.

Compensation indices of radiation-induced wheat-Agropyron elongatum translocations conferring resistance to leaf rust and stem rust

Abstract: Species belonging to the genus Agropyron are an important source of disease resistance for bread wheat. Several resistance genes have been transferred. C-banding and in situ hybridization are the methods of choice for analyzing introgressed alien chromatin. Using these methods, we characterized radiation-induced wheat-Agropyron elongatum chromosome translocation lines carrying the rust resistance genes Sr26 and Sr25/Lr19. Data show that Sr26 is located on the translocation chromosome T6AS.6AL-6Ae#1L

Resistance to powdery mildew (Oidium lycopersicum) in Lycopersicon hirsutum is controlled by an incompletely-dominant gene Ol-1 on chromosome 6.

Abstract: The inheritance of resistance to powdery mildew (Oidium lycopersicum) in Lycopersicon hirsutum was investigated by disease tests in segregating populations obtained by hybridising tomato (L. esculentum) cv Moneymaker with the wild relative L. hirsutum G1.1560. One incompletely dominant gene Ol-1 was found to largely control resistance to the disease. To map Ol-1, DNA pools from seven resistant and ten susceptible F2 plants were analyzed for random amplified polymorphic DNA (RAPD). With 32 primers tested, one RAPD, primed with the sequence 5'-GACGTGGTGA-3', was observed between the susceptible and the resistant bulks, which cosegregated with resistance in the F2 population of L. esculentum × L. hirsutum G1.1560. This RAPD was mapped on chromosome 6 by using an F2 (L. esculentum × L. pennellii) already mapped for 49 RFLPs. RFLP analysis of the F2 from L. esculentum cv Moneymaker × L. hirsutum G1.1560 demonstrated that Ol-1 maps near the Aps-1 region on chromosome 6, in the vicinity of the resistance genes to Meloidogyne spp. (Mi) and to Cladosporium fulvum (Cf-2/Cf-5).

Identification of somatic hybrids of dihaploid Solanum tuberosum lines and S. brevidens by species specific RAPD patterns and assessment of disease resistance of the hybrids.

Abstract: Symmetric somatic hybrids were produced by electrofusion of protoplasts of two dihaploid tuber-bearing potato (Solanum tuberosum L.) lines and Solanum brevidens Phil., a diploid non-tuber-bearing wild potato species. A total of 985 plants was obtained. Verification of nuclear hybridity of putative hybrids was based on additive RAPD patterns, general morphological characteristics and chromosome counts. 53 (90%) calli regenerated into plants which were identified as somatic hybrids. Most of the hybrids were aneuploids at the tetraploid (4×) or hexaploid (6×) level. The 20 hybrids tested expressed a high level of resistance to potato virus Y (PVY N ) characteristic of the S. brevidens parent. Resistance to late blight (Phytophthora infestans (Mont.) de Bary) varied between hybrids, but was on average better than that of the fusion parents. Resistance of hybrids to bacterial stem rot (Erwinia carotovora subsp. atroseptica (van Hall) Dye) was not superior to that of commercial potato cultivars.

Inheritance of Resistance to Mycosphaerella graminicola in Hexaploid Wheat

Abstract: Septoria tritici blotch constitutes a major disease problem of wheat world-wide. To efficiently breed wheat for resistance to this disease, an understanding is required of the inheritance of resistance. Our objective was to study the quantitative inheritance of resistance under field conditions. A nine-parent diallel and a generation mean experiments were conducted at Toluca, Mexico in 1986 and 1987, respectively, to investigate gene effects. General combining ability effects accounted for most of the variation although specific combining ability effects were detected in some crosses. Ias20*5/H567.71, Thornbird, and RPB709.71/Coc contributed the most to reduced disease severity. Reciprocal effects were detected in two of 36 crosses, where RPB709.71/Coc contributed additional reduced disease severity when used as female. The analysis of generation means confirmed results obtained from the diallel. Additive effects were also most important. Dominance effects and epistasis, mostly of the additive × additive type, were found in some crosses. Hence, substantial genetic progress for resistance can be expected among progeny from crosses with resistant parents. However, selection would be most effective if delayed to later generations because of dominance, and choice of the specific female parent may produce a higher level of resistance.

Identification of RFLP markers linked to crown rust resistance genes Pc 91 and Pc 92 in oat.

Abstract: Crown rust, caused by the fungal pathogen Puccinia coronata Cda. f. avenae (Eriks & E. Henn.), is recognized as a major disease of cultivated oat (Avena sativa L.). Control of the pathogen has relied on the identification of resistance genes (designated Pc genes) and their incorporation into oat cultivars. However, the limited durability of single genes conferring high levels of resistance to the disease has depleted the number of such resistance genes. New genes and ways to deploy them are needed to ensure adequate resistance in future oat cultivars [...]