DUT and infection: The differences between the trimeric and dimeric Dut interactions with the SaPIbov1 mutants were further confirmed using a phage-interference spot test assay (see Methods for explanation) where different strains containing WT or mutant SaPIbov1 (StlWT, StlY112A or StlYY-AA) were used as recipients for infection with phages φ11 (trimeric Dut), 80α (trimeric Dut) or φNM1 (dimeric Dut).