Catalase inhibition alters suberization and wound healing in potato (Solanum tuberosum) tubers

In response to wounding, potato (Solanum tuberosum L.) tubers generate hydrogen peroxide (H2O2) in association with suberization, a critical phase of the wound-healing process. In the present study, the effect of aminotriazole (AT), a catalase (CAT, EC 1.11.1.6) inhibitor, on cut tubers was investigated using fresh weight (FW) loss and pathogen attack symptoms as indicators of wound-healing efficiency. Seven days after treatment, AT-treated tuber halves lost more FW and developed infection signs compared with the controls. Thiourea, another CAT inhibitor, as well as exogenous H2O2 treatments induced the same effects as AT suggesting that the alteration of the wound healing may be caused by CAT inhibition and the resulting accumulation of H2O2. Using transgenic tubers, FW losses 1 week after wounding were either higher (CAT repression) or lower (CAT overexpression) than those of the wildtype. When tuber halves were allowed to wound heal for different periods before treatment, AT had no effect on the progress of their wound healing if wound-healed for at least 3 days. This implies that AT may affect early wound-healing-related events, especially those occurring before or during suberization. A time-course analysis of the effects of AT treatment on wounded tuber tissues revealed that AT prevented the deposition of the polyphenolic domain of suberin in association with CAT inhibition and H2O2 accumulation. These data are important in identifying factors that may be required to regulate suberization and contribute to a better understanding of this critical process to hasten its rate and limit wound-related losses in stored potato tubers.