File S1 - Interact to Survive: Phyllobacterium brassicacearum Improves Arabidopsis Tolerance to Severe Water Deficit and Growth Recovery

Supporting information. Table S1, Soil chemical properties of the compost (Neuhaus N2), soil and two mixtures of both. Mixture 1 was sampled before experimentation and mixture 2 was sampled after experimentations. nd: not determined. Soil analysis was performed by ALFA Agricultural Service and Research Building, Soil Testing Laboratory of Auburn University. Figure S1, Soil water potential during soil drying. Soil water potential was determined using a potentiometer (WP4-T dewpoint meter, Decagon Devices, Pullman, WA 99163, USA) during soil drying (from 0.35 to 0.06 g H2O g−1 dry soil). Figure S2, Growth of P. brassicacearum STM196 strain is not affected by soil water deficit. Growth of STM196 strain was represented by cfu/mg of soil under well-watered condition (WW) and water deficit (WD). Data are means (±SE) of 3 replicates. Figure S3, Whole-rosette mean Fv/Fm is not affected by inoculation under well watered condition (WW). Mean Fv/Fm of non-inoculated plants (NI; closed squares) and inoculated plants (I; open squares) during time courses. Data are means (±SE) of 3–32 plants. Grey points represent individuals for each condition (NI; closed symbols and I; open symbols). Figure S4, P. brassicacearum STM196 induces a delayed decrease of Fv/Fm in response to WD. Relationship between whole-rosette Fv/Fm and leaf relative water content of non-inoculated (NI; closed symbols) and STM196-inoculated (I; open symbols) plants under well watered (WW) and water deficit (WD; 6%p) during soil drying (35%, 20%, 10% and 6%) and after rewatering (20%r, 35%r and 35%r at flowering). The dashed line represents the 90%-mortality threshold. Surviving plants with mean Fv/Fm values above the threshold, are represented by triangles (n = 3–10 and n = 3–19 for NI and I plants, respectively) and perishing plants, with mean Fv/Fm below the threshold, are represented by upside-down triangles (n = 3–9 and n = 3 for NI and I plants, respectively). Figure S5, Effect of P. brassicacearum STM196 strain and water deficit on growth, physiology and development of A. thaliana at flowering. A) Dry mass of rosette leaves, B) days to flowering and C) leaf relative water content of non-inoculated (NI) and inoculated (I) plants under well watered (WW) and severe water deficit (WD; 6%p). Data are means (±SE) of 11–27 plants. Different letters indicate significant differences following Kruskal-Wallis test (P (DOCX)