title: Geographical gradient of the eIF4E alleles conferring resistance to potyviruses in pea (Pisum) germplasm.
abstract: BACKGROUND
  The eukaryotic translation initiation factor 4E was shown to be involved in resistance against several potyviruses in plants, including pea. We combined our knowledge of pea germplasm diversity with that of the eIF4E gene to identify novel genetic diversity.
  
  
  RESULTS
  Germplasm of 2803 pea accessions was screened for eIF4E intron 3 length polymorphism, resulting in the detection of four eIF4E(A-B-C-S) variants, whose distribution was geographically structured. The eIF4E(A) variant conferring resistance to the P1 PSbMV pathotype was found in 53 accessions (1.9%), of which 15 were landraces from India, Afghanistan, Nepal, and 7 were from Ethiopia. A newly discovered variant, eIF4E(B), was present in 328 accessions (11.7%) from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The eIF4E(C) variant was detected in 91 accessions (3.2% of total) from India (20%), Afghanistan (33%), the Iberian Peninsula (22%) and the Balkans (9.3%). The eIF4E(S) variant for susceptibility predominated as the wild type. Sequencing of 73 samples, identified 34 alleles at the whole gene, 26 at cDNA and 19 protein variants, respectively. Fifteen alleles were virologically tested and 9 alleles (eIF4E(A-1-2-3-4-5-6-7), eIF4E(B-1), eIF4E(C-2)) conferred resistance to the P1 PSbMV pathotype.
  
  
  CONCLUSIONS
  This work identified novel eIF4E alleles within geographically structured pea germplasm and indicated their independent evolution from the susceptible eIF4E(S1) allele. Despite high variation present in wild Pisum accessions, none of them possessed resistance alleles, supporting a hypothesis of distinct mode of evolution of resistance in wild as opposed to crop species. The Highlands of Central Asia, the northern regions of the Indian subcontinent, Eastern Africa and China were identified as important centers of pea diversity that correspond with the diversity of the pathogen. The series of alleles identified in this study provides the basis to study the co-evolution of potyviruses and the pea host.
authors.affiliation: Department of Plant Biology, Mendel University in Brno, Brno, Czech Republic; CEITEC MENDELU, Mendel University in Brno, Brno, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Konečná
authors.affiliation: Department of Cell Biology and Genetics, Palacky University in Olomouc, Olomouc, Czech Republic.
authors.forename: Dana
authors.initials: D
authors.lastname: Šafářová
authors.affiliation: Department of Cell Biology and Genetics, Palacky University in Olomouc, Olomouc, Czech Republic.
authors.forename: Milan
authors.initials: M
authors.lastname: Navrátil
authors.affiliation: Department of Plant Biology, Mendel University in Brno, Brno, Czech Republic; CEITEC MENDELU, Mendel University in Brno, Brno, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hanáček
authors.affiliation: Western Regional Plant Introduction Station - USDA, Pullman, Washington, United States of America.
authors.forename: Clarice
authors.initials: C
authors.lastname: Coyne
authors.affiliation: Division of Plant Sciences, University of Dundee at James Hutton Institute, Invergowrie, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Flavell
authors.affiliation: Vavilov Institute of Plant Industries, Saint Petersburg, Russian Federation.
authors.forename: Margarita
authors.initials: M
authors.lastname: Vishnyakova
authors.affiliation: John Innes Centre, Norwich, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Ambrose
authors.affiliation: Australian Grains Genebank, Horsham, Victoria, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Redden
authors.affiliation: Department of Botany, Palacky University in Olomouc, Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Smýkal
mesh_terms: D000483:Alleles; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000502:physiology*; D005843:Geography; D018532:Pisum sativum / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D010935:Plant Diseases / Q000821:virology*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D017800:Potyvirus / Q000472:pathogenicity*
chemical_list: D039561:Eukaryotic Initiation Factor-4E; D010940:Plant Proteins