FIGURE 6.

Fate of (R)-mellein and (-)-terremutin from plantlets incubating medium or from medium of B. subtilis-PTA-271-pretreated plantlets. Eight weeks old plantlets treated with PTA-271 were transferred in a new MS medium containing (R)-mellein (Bs + M) 350 μg/L (A,B) or (-)-terremutin (Bs + T) 750 μg/L (C,D). The same experiment was performed with non-bacteria pretreated plantlets, then transferred on (-)-terremutin 750 μg/L (Ctl + T) or (R)-mellein 350 μg/L (Ctl + M). Phytotoxin concentrations were determined either: daily in the plant culture media from 0 to 72 h (A,C), or 72 h post-exposure as percentage accumulated in shoots (S) and roots (R) (B,D). Data are means ± SD of three independent experiments, each with triplicates (at least four plantlets by replicate). The toxin controls indicated none physicochemical disappearance. Phytotoxins were not detectable inside bacterial pellet. Vertical bars with different letters are significantly different (Multiple Comparison procedures with Tukey’s test, P < 0.05).