Enhanced biosynthesis of the natural antimicrobial glyceollins in soybean seedlings by priming and elicitation

Glyceollins are a class of antimicrobial prenylated pterocarpans produced in soybean seedlings upon fungus elicitation. Priming with reactive oxygen species (ROS) prior to elicitation with Rhizopus oligosporus/oryzae (R) was investigated for its potential to enhance glyceollin production. ROS-priming prior to R-elicitation (ROS + R) increased glyceollin production (8.6 ± 0.9 µmol/g dry weight (DW)) more than 4-fold compared to elicitation without priming (1.9 ± 0.4 µmol/g DW). Furthermore, ROS-priming was superior to two physical primers which were used as benchmark primers, namely slicing (5.0 ± 0.6 µmol glyceollins/g DW) and sonication (4.8 ± 1.0 µmol glyceollins/g DW). Subsequently, the robustness of ROS + R was assessed by applying it to another soybean cultivar, where it also resulted in a significantly higher glyceollin content than R-elicitation without priming. ROS-priming prior to elicitation provides opportunities for improving the yield in large-scale production of natural antimicrobials due to the ease of application and the robustness of the effect across cultivars.