Functional dissection of naturally occurring amino acid substitutions in eIF4E that confers recessive potyvirus resistance in plants.
Naturally existing variation in the eukaryotic translation initiation factor 4E (eIF4E) homolog encoded at the pvr1 locus in Capsicum results in recessively inherited resistance against several potyviruses. Previously reported data indicate that the physical interaction between Capsicum-eIF4E and the viral genome-linked protein (VPg) is required for the viral infection in the Capsicum-Tobacco etch virus (TEV) pathosystem. In this study, the potential structural role(s) of natural variation in the eIF4E protein encoded by recessive resistance alleles and their biological consequences have been assessed. Using high-resolution three-dimensional structural models based on the available crystallographic structures of eIF4E, we show that the amino acid substitution G107R, found in many recessive plant virus resistance genes encoding eIF4E, is predicted to result in a substantial modification in the protein binding pocket. The G107R change was shown to not only be responsible for the interruption of VPg binding in planta but also for the loss of cap binding ability in vitro, the principal function of eIF4E in the host. Overexpression of the Capsicum-eIF4E protein containing the G107R amino acid substitution in Solanum lycopersicum indicated that this polymorphism alone is sufficient for the acquisition of resistance against several TEV strains.
Yeam
Inhwa
I
Department of Plant Breeding and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
Cavatorta
Jason R
JR
Ripoll
Daniel R
DR
Kang
Byoung-Cheorl
BC
Jahn
Molly M
MM
D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001120:Arginine / Q000235:genetics; D002212:Capsicum / Q000276:immunology / Q000378:metabolism / Q000821:virology*; D039561:Eukaryotic Initiation Factor-4E / Q000737:chemistry / Q000378:metabolism*; D005998:Glycine / Q000235:genetics; D007113:Immunity, Innate / Q000276:immunology*; D018551:Solanum lycopersicum / Q000235:genetics / Q000821:virology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology*; D030821:Plants, Genetically Modified; D017800:Potyvirus / Q000502:physiology*; D011485:Protein Binding; D039381:RNA Cap-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014026:Nicotiana; D017361:Viral Nonstructural Proteins / Q000378:metabolism
D039561:Eukaryotic Initiation Factor-4E; D050505:Mutant Proteins; D039381:RNA Cap-Binding Proteins; D012261:Ribonucleoproteins; D017361:Viral Nonstructural Proteins; C102206:genome-linked viral protein, potato virus Y; D001120:Arginine; D005998:Glycine