Fig. 6: Rhizobium sp. 4F10 ocd gene is required for bacterial fitness and stress protection in plants.

a Overview of the ocd gene cluster in the genome of Rhizobium sp. 4F10. Genes are colored based on predicted functions, and names are assigned according to the query sequence. b ocd gene mediated transformation pathway from L-Ornithine to L-Proline. c Phenotypes of plants (Col-0) inoculated with Rhizobium sp. 4F10 and △ocd grown on 1/2 MS (mock) plates or PEG plates (osmotic stress). n = 10 biological replicates for individual group (n = 5). d Primary root length and (e) shoot fresh weight were assessed for plants inoculated by Rhizobium sp. 4F10 or △ocd, with uninoculated plants serving as the control group (n = 10). Primary root length and fresh weight were rescored at 9 d and 14 d after inoculation, respectively. Data represent mean (bar) ± standard error of the mean (error bar). Only the significant differences (marked with P-value) between different genotypes are listed (two-sided Student’s t test). Three independent experiments showed similar results. f Growth rate of Rhizobium sp. 4F10 and △ocd grown in the LB liquid medium were measured as optical density (n = 3). Data represent mean (dot) ± standard error of the mean (error bar). Only the significant differences (marked with P-value) between Rhizobium sp. 4F10 and △ocd are shown (two-sided Student’s t test). Three independent experiments showed similar results. g Phenotypes and (h) quantification results of the survival rate of Rhizobium sp. 4F10 and △ocd after 1 minute and 5 minutes of treatment with 1% H₂O₂ (n = 6). Data represent mean ± standard error of the mean (error bar). Only the significant differences (marked with P-value) between Rhizobium sp. 4F10 and △ocd at different time points are shown (two-sided Student’s t test).