Reactive Oxygen Species Alleviate Cell Death Induced by Thaxtomin A in <i>Arabidopsis thaliana</i> Cell Cultures

• Main Authors: Fatima Awwad, Guillaume Bertrand, Michel Grandbois, Nathalie Beaudoin
• Format: Article
• Language: English
• Published: MDPI AG 2019-09-01
• Series: Plants
• Subjects: cell wall rigidity; H₂O₂; programmed cell death; thaxtomin A
• Online Access: https://www.mdpi.com/2223-7747/8/9/332

Thaxtomin A (TA) is a cellulose biosynthesis inhibitor synthesized by the soil actinobacterium <i>Streptomyces scabies</i>, which is the main causal agent of potato common scab. TA is essential for the induction of scab lesions on potato tubers. When added to <i>Arabidopsis thaliana</i> cell cultures, TA induces an atypical programmed cell death (PCD). Although production of reactive oxygen species (ROS) often correlates with the induction of PCD, we observed a decrease in ROS levels following TA treatment. We show that this decrease in ROS accumulation in TA-treated cells is not due to the activation of antioxidant enzymes. Moreover, <i>Arabidopsis</i> cell cultures treated with hydrogen peroxide (H₂O₂) prior to TA treatment had significantly fewer dead cells than cultures treated with TA alone. This suggests that H₂O₂ induces biochemical or molecular changes in cell cultures that alleviate the activation of PCD by TA. Investigation of the cell wall mechanics using atomic force microscopy showed that H₂O₂ treatment can prevent the decrease in cell wall rigidity observed after TA exposure. While we cannot exclude the possibility that H₂O₂ may promote cell survival by altering the cellular redox environment or signaling pathways, our results suggest that H₂O₂ may inhibit cell death, at least partially, by reinforcing the cell wall to prevent or compensate for damages induced by TA.