Figure 6. Effects of mutations of genes encoding several putative glycosyltransferases on biofilm formation and EPS production in Xoc wild-type and ΔrpfG mutant backgrounds.

(A) Elevated biofilm formation in Xoc ΔrpfG was reduced to the wild-type level when xagA, xagB and gumD, but not pgaA or pgaC was deleted singly in the ΔrpfG genotype. The full length xagA and gumD genes restored the ability of biofilm formation in ΔrpfG/xagA and ΔrpfG/gumD mutants, respectively. (B) The ability of ΔgumD to form biofilm was greatly attenuated in the wild-type background, but was restored by complementation. Biofilm formation in the ΔpgaA, ΔpgaC, ΔxagA and ΔxagB single mutants was not altered compared to the wild-type strain. (C) EPS production was significantly reduced in the ΔgumD mutant, but not in ΔpgaA, ΔpgaC, ΔxagA and ΔxagB mutants compared to the wild-type. These experiments were repeated at least three times with similar results.