P-242 - Exploring the role of DNA polymerase δ subunit 1 in geminivirus resistance in Arabidopsis thaliana

Geminiviruses are single-stranded DNA viruses that infect several economically important crop species, including cassava, cotton, tomato, and other members of the Solanaceae family. These viruses rely on host DNA polymerases for their replication, with DNA polymerase δ (POLD1) playing a critical role. A recent study identified specific amino acid changes within the cassava POLD1 protein that correlated with dominant resistance to cassava geminiviral pathogens. However, the underlying molecular mechanisms of POLD1-mediated resistance and its applicability in diverse plant species remain unclear. To investigate if this resistance mechanism is functional beyond cassava, we have identified a strain of Arabidopsis containing a homozygous mutation in POLD1 for challenge with beet curly top virus (BCTV) to assess for geminivirus resistance. Additionally, we are undertaking a transgenic approach to directly study cassava PolD1-resistant alleles in Arabidopsis during geminiviral infection. By conducting these experiments in Arabidopsis as proof of concept, we will (1) determine if POLD1 resistant alleles can function in systems other than cassava and (2) have established a tractable model system to further understand the molecular function of POLD1 resistance alleles.