Fig. 5

Confirmation of bacterial provided thermotolerance. (A) Heat shock treatment regime: NHS, no heat shock control; NHS + Bac, inoculated plants with no heat shock; HS, heat shock at 45 °C; Pr + HS, thermo-priming followed by heat shock at 45 °C; Bac + HS, inoculate plants with bacteria prior to heat shock at 45 °C. (B) Hydroponically grown Arabidopsis seedlings were inoculated with live or heat-killed Variovorax sp. CF313 and co-cultured for 7 days prior to heat shock at 45 °C for 14 min. The supernatant of the bacteria culture solution was added to test for an indirect effect of bacterial-produced molecules on plant thermotolerance. After 4 days of recovery plants were harvested to measure chlorophyll content. Box plots represent relative chlorophyll content compared to non-heat shocked (NHS) control plants. Box plots display the 25th – 75th percentiles with the median (horizontal line) (n = 9–12 wells with ca. 10 seedlings each). Different letters indicate significant difference between treatments (Fisher’s LSD, P < 0.05)