Figure 3.

Phloroglucinol treatment of parental brine shrimp increased the resistance of their progeny for three subsequent generations against a bacterial infection with Vibrio parahaemolyticus or Vibrio harveyi. The parental generation treatment population (TF0) was treated with phloroglucinol (2 μM) until DAH16 and then three subsequent generations TF1, TF2, and TF3 were kept unexposed to phloroglucinol. The parental generation control population (CF0) as well as three subsequent generations CF1, CF2, and CF3 were not treated with phloroglucinol (see Figure 1 for detailed explanations). F1, F2, and F3 larvae from treated and untreated parents were subsequently used for vibrio (10⁷ cells/ml) challenge trials scoring the survival from 12 until 60 h post challenge with Vibrio parahaemolyticus (AHPND strain M0904) (A) or Vibrio harveyi (strain BB120) (B). During the subsequent common garden experiment, age- and size-synchronized 1-day-old larvae were used for vibrio (10⁷ cells/ml) challenge trials scoring the survival from 12 until 48 h post challenge with Vibrio parahaemolyticus (AHPND strain M0904) (C) or Vibrio harveyi (strain BB120) (D). Error bars represent the standard deviation (n = 7) and stars represent the significant difference over time at each time point (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, *****P < 0.00001) between the treatment groups and the control groups.