View source for Puccinia coronata f. sp. avenae

{{Short description|Variation of the crown rust fungus}}
{{Infraspeciesbox special 
| name = ''Puccinia coronata'' f.sp. ''avenae''
| image = 
| image_alt = 
| image_caption = 
| genus = Puccinia
| species = coronata
| variety = avenae
| infraspecies_rank1_name = Forma specialis
| infraspecies_rank1 = ''avenae''
| infraspecies_rank1_abbrev = f.sp.
}}
'''''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'').<ref name= "Mayama March 1982">{{cite journal|last1=Mayama|first1=S.|last2=Matasuura|first2=Y|last3=Iida|first3=H|last4=Tani|first4=T|title=The role of avenalumin in the resistance of oat to crown rust, ''Puccinia coronoata'' f. sp. ''avenae''|journal=[[Physiological Plant Pathology]]|date=March 1982|volume=20|issue=2|pages=189–199|doi=10.1016/0048-4059(82)90084-4}}</ref> Almost every growing region of oat has been affected by this pathogen at one point or another.<ref name="Cereal Disease Lab" /> During particularly bad epidemics, the worldwide crop yields have been reduced by up to 40%.<ref name="Cereal Disease Lab" /> 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.<ref name="Cereal Disease Lab">{{cite web|title=Oat crown rust|url=http://www.ars.usda.gov/Main/docs.htm?docid=9919|website=Cereal Disease Laboratory|publisher=United States Department of Agriculture &#124; Agricultural Research Service|accessdate=19 October 2015}}</ref> ''Pca'' urediniospores germinate the best at temperature between {{convert|10-30|C|F|0}} with germ-tube growth optimized at {{convert|20|C|F|0}}.<ref>{{cite journal|last1=Kochman|first1=J.K.|last2=Brown|first2=J.F.|title=Effect of temperature, light and host on prepenetration development of ''Puccinia graminis avenae'' and ''Puccinia coronata avenae''|journal= [[Annals of Applied Biology]] |date=March 1976|volume=82|issue=2|pages=241–249|doi=10.1111/j.1744-7348.1976.tb00559.x}}</ref>

The [[virulence]] of ''Pca'' and the resistance of wild oat plants is a highly studied topic. It seems that the [[plant disease resistance|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.<ref name=":0">{{cite journal|last1=Dinoor|first1=Amos|title=Oat crown rust resistance in Israel|journal= [[Annals of the New York Academy of Sciences]] |date=February 1977|volume=287|issue=1|pages=357–366|doi=10.1111/j.1749-6632.1977.tb34253.x|bibcode=1977NYASA.287..357D|s2cid=83866651}}</ref> There are most likely multiple traits that control both virulence and resistance which suggests a very interactive [[Host–parasite coevolution|host-parasite coevolution]].<ref name=":0" /> A few specific [[Locus (genetics)|loci]] have been found to confer resistance such as ''{{visible anchor|Pca (locus)|text=Pca}}'' which conferred a dominant, resistant phenotype to nine different isolates of ''P. coronata''.<ref name=":1" /> 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.<ref name=":1">{{cite journal|last1=Rayapati|first1=P.J.|last2=Greogry|first2=J.W.|last3=Lee|first3=M|last4=Wise|first4=R.P.|title=A linkage map of diploid ''Avena'' based on RFLP loci and a locus conferring resistance to nine isolates of ''Puccinia coronata'' var. ''<nowiki>'avenae'</nowiki>''|journal= [[Theoretical and Applied Genetics]] |date=December 1994|volume=89|issue=7|pages=831–837|doi=10.1007/BF00224505|pmid=24178091|s2cid=22100351}}</ref> Some studies suggest that the responses are dependent upon the physiological race of the rust involved due to mutations that arise in separate races.<ref>{{cite journal|last1=Dumsday|first1=J.L|last2=Smith|first2=K.F.|last3=Forster|first3=J.W.|last4=Jones|first4=E. S.|title=SSR-based genetic linkage analysis of resistance to crown rust (''Puccinia coronata'' f. sp. ''lolii'') in perennial ryegrass (''Lolium perenne'')|journal= [[Plant Pathology]] |date=October 2003|volume=52|issue=5|pages=628–637|doi=10.1046/j.1365-3059.2003.00884.x|doi-access=free}}</ref>

One way in which the expression of certain genes has been found to combat ''Pca'' is through the production of [[avenalumin]]s.<ref name="Mayama March 1982" /> Avenalumins are [[antimicrobial compound]]s which inhibit [[hypha]]l growth, thus preventing ''P. coronata'' from spreading.<ref name="Mayama March 1982" /> Avenalumins are only found in infected areas of plants and nowhere else.<ref name="Mayama March 1982" /> The production of avenalumins is regulated by some of the same genes that have been found to confer [[crop fungal disease resistance|resistance in certain lines of oats]], thus indicating their importance in resistance.<ref name="Mayama March 1982" /> In addition to total resistance to specific [[race (biology)|race]]s, in such cases as the production avenalumins, partial or [[horizontal resistance]] provides a way to reduce the effect of ''P. coronata''.<ref name="Briere 1994">{{cite journal|last1=Briere|first1=S.C.|last2=Kushalappa|first2=A.C.|last3=Mather|first3=D.E|title=Screening for Partial Resistance to an Isolate of Crown Rust (''Puccinia coronata'' f. sp. ''avenae'') Race 264 in Oat Cultivars and Breeding Lines|journal= [[Canadian Journal of Plant Pathology]] |date=1994|volume=16|issue=1|pages=49–55|doi=10.1080/07060669409500787|bibcode=1994CaJPP..16...49B }}</ref>

== References ==
{{Reflist}}
{{DISPLAYTITLE:''Puccinia coronata'' f. sp. ''avenae''}}
[[Category:Puccinia|coronata avenae]]
[[Category:Fungi described in 1837]]
[[Category:Fungal plant pathogens and diseases]]
[[Category:Galls]]
[[Category:Oats diseases]]
[[Category:Taxa named by August Carl Joseph Corda]]
[[Category:Forma specialis taxa]]