Evidence that variation in DNA polymerase delta subunit 1 underlies geminivirus resistance in diverse plants

Identifying loci conferring resistance to geminiviruses is an on-going priority in diverse crop species. Multiple geminivirus resistance QTLs and genes have been described, including most recently DNA polymerase delta subunit 1 ( POLD1 ) in both cassava and tomato. From this, we hypothesized that POLD1-mediated resistance is present in a broad range of plant species. An analysis of multiple species with published geminivirus resistance QTLs was done to identify species with POLD1 variation consistent with known resistance alleles. Further, allele mining of over 7,000 accessions across 10 different genera, from both dicots and monocots, identified additional substitutions in key regions of the POLD1 protein as possible novel resistance alleles. These results provide evidence that POLD1 variation is a source for geminivirus resistance in diverse plants including cotton, soybean, squash, wheat, and maize.