Allele mining of eukaryotic translation initiation factor genes inPrunusspecies for the identification of new sources of resistance to sharka

Abstract

AbstractBackgroundMembers of the eukaryotic translation initiation complex are co-opted in viral infection, leading to susceptibility in many crop species, including stone fruit trees (Prunus spp). Therefore, modification of one of those eukaryotic translation initiation factors or changes in their gene expression may result in resistance.ObjectiveWe searched the crop and wildPrunusgermplasm from the Armeniaca and Amygdalus taxonomic sections for allelic variants in theeIF4EandeIFiso4Egenes, to identify alleles potentially linked to resistance to thePlum Pox Virus(PPV).Methodology and resultsOver one thousand stone fruit accessions (1,397) were screened for variation in eIF4E and eIFiso4E transcript sequences which are in single copy within the diploidPrunusgenome. We identified new alleles for both genes that are not evident in haplotypes associated with PPV susceptible individuals. Overall, analyses showed thateIFiso4Eis genetically more constrained since it displayed less polymorphism thaneIF4E. We also demonstrated more variation at both loci in the related wild species than in crop species. As the eIFiso4E translation initiation factor was identified as indispensable for PPV infection inPrunusspecies, a selection of ten differenteIFiso4Ehaplotypes along 13 individuals were tested by infection with PPV and eight of them displayed a range of reduced susceptibility to resistance, indicating new potential sources of resistance to sharka.