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Puccinia coronata f.sp. avenae
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Pucciniomycetes
Order: Pucciniales
Family: Pucciniaceae
Genus: Puccinia
Species: P. coronata
Variety: P. c. var. avenae
Forma specialis: P. c.  f.sp. avenae
Trionomial name
Puccinia coronata f.sp. avenae

Puccinia coronata f. sp. avenae is the variation ( forma specialis, f. sp.) of the crown rust fungus ( Puccinia coronata) which infects oat plants (Avena sativa). [1] Almost every growing region of oat has been affected by this pathogen at one point or another. [2] During particularly bad epidemics, the worldwide crop yields have been reduced by up to 40%. [2] One reason why Pca has such a prominent effect is that the conditions which favor oat production also favor the growth and inoculation of the rusts: Meaning that years in which the highest yields of crops are expected are the same years in which losses are the highest as well. [2] Pca urediniospores germinate the best at temperature between 10–30 °C (50–86 °F) with germ-tube growth optimized at 20 °C (68 °F). [3]

The virulence of Pca and the resistance of wild oat plants is a highly studied topic. It seems that the resistance level of the oat plant is dependent upon which race of Pca is acting on it; the virulence of the fungal pathogen also seems to depend upon which strain the strain of oat being attacked. [4] There are most likely multiple traits that control both virulence and resistance which suggests a very interactive host-parasite coevolution. [4] A few specific loci have been found to confer resistance such as Pca which conferred a dominant, resistant phenotype to nine different isolates of P. coronata. [5] An additional isolate of P. coronata was also resisted, although another, un-linked gene may be involved which correlates the theory that resistance and virulence in A. sativa are controlled by multiple genes. [5] Some studies suggest that the responses are dependent upon the physiological race of the rust involved due to mutations that arise in separate races. [6]

One way in which the expression of certain genes has been found to combat Pca is through the production of avenalumins. [1] Avenalumins are antimicrobial compounds which inhibit hyphal growth, thus preventing P. coronata from spreading. [1] Avenalumins are only found in infected areas of plants and nowhere else. [1] The production of avenalumins is regulated by some of the same genes that have been found to confer resistance in certain lines of oats, thus indicating their importance in resistance. [1] In addition to total resistance to specific races, in such cases as the production avenalumins, partial or horizontal resistance provides a way to reduce the effect of P. coronata. [7]

References

  1. ^ a b c d e Mayama, S.; Matasuura, Y; Iida, H; Tani, T (March 1982). "The role of avenalumin in the resistance of oat to crown rust, Puccinia coronoata f. sp. avenae". Physiological Plant Pathology. 20 (2): 189–199. doi: 10.1016/0048-4059(82)90084-4.
  2. ^ a b c "Oat crown rust". Cereal Disease Laboratory. United States Department of Agriculture | Agricultural Research Service. Retrieved 19 October 2015.
  3. ^ Kochman, J.K.; Brown, J.F. (March 1976). "Effect of temperature, light and host on prepenetration development of Puccinia graminis avenae and Puccinia coronata avenae". Annals of Applied Biology. 82 (2): 241–249. doi: 10.1111/j.1744-7348.1976.tb00559.x.
  4. ^ a b Dinoor, Amos (February 1977). "Oat crown rust resistance in Israel". Annals of the New York Academy of Sciences. 287 (1): 357–366. Bibcode: 1977NYASA.287..357D. doi: 10.1111/j.1749-6632.1977.tb34253.x. S2CID  83866651.
  5. ^ a b Rayapati, P.J.; Greogry, J.W.; Lee, M; Wise, R.P. (December 1994). "A linkage map of diploid Avena based on RFLP loci and a locus conferring resistance to nine isolates of Puccinia coronata var. 'avenae'". Theoretical and Applied Genetics. 89 (7): 831–837. doi: 10.1007/BF00224505. PMID  24178091. S2CID  22100351.
  6. ^ Dumsday, J.L; Smith, K.F.; Forster, J.W.; Jones, E. S. (October 2003). "SSR-based genetic linkage analysis of resistance to crown rust (Puccinia coronata f. sp. lolii) in perennial ryegrass (Lolium perenne)". Plant Pathology. 52 (5): 628–637. doi: 10.1046/j.1365-3059.2003.00884.x.
  7. ^ Briere, S.C.; Kushalappa, A.C.; Mather, D.E (1994). "Screening for Partial Resistance to an Isolate of Crown Rust (Puccinia coronata f. sp. avenae) Race 264 in Oat Cultivars and Breeding Lines". Canadian Journal of Plant Pathology. 16 (1): 49–55. Bibcode: 1994CaJPP..16...49B. doi: 10.1080/07060669409500787.
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