Relative mRNA levels of CBF and COR genes in the cbf1 (a), cbf2 (b), cbf3 (c), cor47 (d) and ice1 (e) mutants during the post-thaw recovery period. The values for non-inoculated wild-type (Col) plants was set to 1.00, and the values of the colonized plants expressed relative to them. Data are means of three independent experiments ± SD. Asterisks indicate significant differences compared to the non-inoculated plants (*P < .05, **P < .01, t-test). Black (white) bars: P. indica-(un-)colonized plants.