KASP markers reveal established and novel sources of resistance to Pea seed-borne mosaic virus in pea genetic resources.

Pea seed-borne mosaic virus (PSbMV) is both seed-borne and aphid transmitted and can cause economic losses in pea (Pisum sativum L.) production by reducing yield through decreased seed weight and number. The P1 pathotype is especially virulent, affecting this important vegetable crop across the United States and internationally in regions of West Asia, North Africa, Europe, and Australia. Previously, two Kompetitive Allele-Specific PCR (KASP) genotyping markers (eIF4E resistant 1 and 2) were developed and validated on P. sativum accessions identifying two PSbMV pathotype P1 resistance alleles in the eukaryotic translation initiation factor gene, eIF4E. The current study utilized these novel markers to rapidly evaluate 318 genetic resource accessions maintained as part of the USDA National Plant Germplasm System's Pea Single Plant Collection (PSPC). The evaluations also included 58 commercial and other plant introduction (PI) lines that were assessed for the two eIF4E resistance alleles. All genotyping results were validated in greenhouse assays by confirmation of observable disease symptoms following inoculations and by ELISA. The eIF4E resistant 1 and 2 alleles were found in 18 accessions from the PSPC, 5 commercial lines, and 14 other PI accessions. A single PSPC accession showed resistance to PSbMV pathotype P1 that is believed to be a novel source of resistance based on sequencing analysis of eIF4E. Sources of resistance were identified in the PSPC and in commercial cultivars that can be introgressed into breeding lines using traditional techniques to reduce time and cost required to generate germplasm with superior disease-resistant traits.