FIGURE 1.

The EPS assays for all RR gene mutants of Xoc GX01 strain. The EPS biosynthesis ability of RR gene mutants was observed on solid medium NA plus 2% sucrose. The names of each mutant and the wild type strain were labeled beneath the colonies. One microliter of each bacterial culture (OD₆₀₀ = 0.1) was inoculated on the plate, and the bacteria were grown for 72 h at 28°C. A five-degree scoring system had been established for EPS plate assay, adapted from the method by Tang et al. (1991), in which EPS production of each strain was scored by the colonial morphology and size. The degree of EPS production of each strain was listed in Table 2. (A) The EPS assays for RR gene mutant from GX_XOC0263 to GX_XOC2203. (B) The EPS assays for RR gene mutant from GX_XOC2221 to GX_XOC4109 and genetic complementary strain of NK2201.