Quantitative resistance of flax to flax rust (<i>Melampsora lini</i>)

Kowalska, Anna; Niks, Rients E.

doi:10.1080/07060669809500425

Cited by 2 publications

(8 citation statements)

References 27 publications

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“…Fibre flax accessions were selected from previous experiments (Kowalska and Niks 1998): quantitatively resistant Afganistan with low IF, L.U. from Bombay and Resistenta with medium IF, and the most susceptible accession, Cascade.…”

Section: Plant Materialsmentioning

confidence: 99%

“…This isolate was avirulent to 21 flax genes for resistance, including K and Nl (Kowalska and Niks 1998). Inoculum was prepared as a mixture of urediospores with Lycopodium powder (1:10, v/v).…”

Section: Pathogenmentioning

confidence: 99%

“…Most of the accessions of wild Linum species did not show any macroscopic symptoms of infection after inoculation with M. lini (Kowalska and Niks 1998). Some of the species may be nonhosts of the rust.…”

Section: Introductionmentioning

confidence: 98%

“…The accessions differed in IF, but in contrast with the PR in the barley -P. hordei pathosystem, they did not differ in LP. The low IF was associated with the appearance of erratic necrosis; on some plants, pustules were interspersed with few necrotic flecks (Kowalska and Niks 1998).…”

Section: Introductionmentioning

confidence: 99%

“…In a previous study (Kowalska and Niks 1998), the quantitative resistance in the flax -M. lini pathosystem was investigated and compared with that of partial resistance (PR) of barley to the barley leaf rust fungus (Puccinia hordei). PR retards epidemic development, although plants show a nonhypersensitive infection type (Parlevliet 1979).…”

Section: Introductionmentioning

confidence: 99%

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Histology of quantitative resistance in flax to the flax rust fungus (Melampsora lini)

Kowalska

Niks

1999

Canadian Journal of Plant Pathology

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Macroscopical and histological research is useful to characterize quantitative resistance. Analysis of histological components of the resistance to the flax rust fungus {Melampsora lini) was carried out on seedlings of seven flax (Linum usitatissimum) accessions: five fibre flax accessions with various levels of quantitative resistance and two near-isogenic lines of linseed with gene AT or NI. Flax seedlings were inoculated with uredospores. Collected leaves of the flax accessions were stained with Chlorazol Black E. It was found that in the pathosystem flax -M. lini, a lower number of pustules (lower infection frequency) on quantitatively resistant accessions did not result from mechanisms acting before stomatal penetration by the fungus. Reduced infection frequency was associated with increased rates of early abortion of the rust fungus but rates of this abortion were not large enough to explain the low infection frequency on the quantitatively resistant accessions Afganistan and Solido. In both of the accessions the number of haustoria formed 2 days after inoculation and the size of established colonies after 5 days were reduced. Hyphae of the fungus in the accession Solido stained intensely, and appeared stunted and crinkled. Most of the established colonies in the quantitatively resistant accessions were associated with plant cell necrosis, and at the macroscopic level, pustules were interspersed with some necrotic flecks. This indicates that quantitative resistance of flax to flax rust was caused by incomplete hypersensitivity. Various intensities of the hypersensitive reaction were involved with the resistance of some wild Linum species against M. lini, although in some other accessions it was based on prehaustorial arrestment of the infection units.Résumé : La recherche macroscopique et histologique est utile pour caractériser la resistance quantitative. L'analyse, au niveau histologique, de composants de la resistance a la rouille du lin (Melampsora lini) a été effectuée sur sept obtentions de lin (Linum usitatissimum) : cinq obtentions de lin textile possédant de la resistance quantitative a des degrés divers et deux lignées quasi-isogéniques de lin cultivé possédant les gènes K et NL Des semis de lin ont été inoculés avec des urédospores. Des feuilles provenant des obtentions de lin ont été récoltées et colorées au noir de chlorazol E. On a trouvé que dans Ie pathosystème lin -M. lini un plus petit nombre de pustules (intensité d'infection plus faible) sur des obtentions a resistance quantitative n'était pas Ie résultat de mécanismes agissant avant la penetration du stomate par Ie champignon. La diminution de l'intensité d'infecüon était reliée a 1'augmentation du taux d'avortement précoce du champignon de la rouille, mais Ie taux d'avortement n'était pas suffisamment élevé pour expliquer la plus faible intensité d'infection des obtentions quantitativement résistantes Afganistan et Solido. Chez ces deux obtentions, Ie nombre d'haustoriums formés 2 jours après 1'inoculation et la dimension des colonies ...

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Section: Plant Materialsmentioning

confidence: 99%

Section: Pathogenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Histology of quantitative resistance in flax to the flax rust fungus (Melampsora lini)

Kowalska

Niks

1999

Canadian Journal of Plant Pathology

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Rust of flax and linseed caused byMelampsora lini

Lawrence¹,

Dodds

Ellis

2007

Molecular Plant Pathology

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SUMMARYMelampsora lini , while of economic importance as the causal agent of rust disease of flax and linseed, has for several decades been the 'model' rust species with respect to genetic studies of avirulence/virulence. Studies by Harold Flor demonstrated that single pairs of allelic genes determine the avirulence/virulence phenotype on host lines with particular resistance genes and led him to propose his famous 'gene-for-gene' hypothesis. Flor's inheritance studies, together with those subsequently carried out by others, also revealed that, in some cases, an inhibitor gene pair and an avirulence/virulence gene pair interact to determine the infection outcome on host lines with particular resistance genes. Recently, avirulence/virulence genes at four loci, AvrL567 , AvrM , AvrP4 and AvrP/AvrP123 , have been cloned. All encode novel, small, secreted proteins that are recognized inside plant cells. Yeast two-hybrid studies have shown that the AvrL567 proteins interact directly with the resistance gene protein. The molecular basis of Flor's gene-for-gene relationship has now been elucidated for six interacting gene pairs: those involving resistance genes L5 , L6 , L7 , M , P and P2 , where both the resistance gene and the corresponding avirulence gene have been cloned. In other inheritance studies it has been shown that M. lini does not possess a (+) and (-) mating system, but may possess a two factor system. Double-stranded (ds) RNA molecules occur in many strains of M . lini : examination of the progeny of one strain that possesses 11 dsRNA molecules revealed that they fall into three transmission units, designated L, A and B. The L unit consists of a single large dsRNA of 5.2 kbp while the A and B units each consist of five dsRNAs in the size range 1.1-2.8 kbp. The three units have different sexual and asexual transmission characteristics. The L unit is encapsidated in a virus-like particle, whereas the other units are not encapsidated. The population and coevolutionary aspects of M. lini on a wild, native Australian host species, Linum marginale , have been extensively investigated. A recent molecular analysis revealed that the M. lini isolates from L. marginale fall into two distinct lineages, one of which is apparently hybrid between two diverse genomes. Isolates in this lineage are largely fixed for heterozygosity, which suggests that sexual recombination does not occur in this lineage.

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Quantitative resistance of flax to flax rust (Melampsora lini)

Cited by 2 publications

References 27 publications

Histology of quantitative resistance in flax to the flax rust fungus (Melampsora lini)

Histology of quantitative resistance in flax to the flax rust fungus (Melampsora lini)

Rust of flax and linseed caused byMelampsora lini

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