Fig. 3: Regulation of G. sunshinyii DMSP synthesis and role of DsyGD in salt tolerance.
From: Alternative dimethylsulfoniopropionate biosynthesis enzymes in diverse and abundant microorganisms
a, G. sunshinyii DMSP and DMSHB accumulation measured by GC. b, dysG transcription from cultures grown under standard conditions (35 PSU MBM and 0.5 mM NH4Cl), low salt (5 PSU), high salt (50 PSU) or high nitrogen (10 mM NH4Cl). DMSP and DMSHB values in a represent the mean of three independent biological replicates with the error bars indicating the respective standard deviations. For a, statistically significant differences compared with control conditions were determined using a two-sided Student’s t-test (DMSP group, low salt: ***P = 0.0002; high salt: *P = 0.0409; high N: *** P = 0.0002. DMSHB group, low salt: **P = 0.0013 and ***P = 0.0004). For the RT–qPCR assays in b, the mean values of three technical replicates for each of three independent biological replicates are shown. The error bars indicate standard deviation. For b, statistically significant differences compared with control conditions were determined using a two-sided Student’s t-test (low salt: ****P = 1.31 × 10−6; high salt: *** P = 0.0009; high N: ****P = 3.219 × 10−5). c, Growth of wild type E. coli MC4100, the salt-sensitive E. coli otsA−mutant strain FF4169 (deficient in trehalose production) and FF4169 strains expressing cloned dsyGD was monitored in media containing 0.5 M NaCl alone or with 1 mM GB, DMSP or DMSP synthesis intermediates (MTHB and DMSHB). The arrows indicate the three strains that did not grow. The values shown represent the mean of three biological replicates with the error bars indicating the respective standard deviations. d, DMSP levels in selected cells after the 36 h incubation experiments shown in c. The mean values of three biological replicates are shown with the error bars indicating standard deviation. ND, not detected.
