Exogenous dopamine ameliorates chilling injury in banana fruits by enhancing endogenous dopamine and glycine betaine accumulation and promoting ROS scavenging system activity

This study explored the efficiency of exogenous dopamine in ameliorating chilling injury in banana fruits during storage at 7 oC for 21 days. By 150 mu M dopamine treatment, alleviating chilling injury in banana fruits was associated with lower electrolyte leakage and MDA accumulation, revealing membrane integrity maintenance. Banana fruits treated with 150 mu M dopamine exhibited higher endogenous dopamine accumulation, which could be ascribed to triggering the expression of TyrDC gene. By 150 mu M dopamine treatment, higher endogenous dopamine accumulation in banana fruits was concomitant with higher endogenous glycine betaine accumulation arising from provoking the expression of CMO and BADH genes and enhancing the activity of BADH enzyme. Banana fruits treated with 150 mu M dopamine exhibited higher chlorophyll accumulation due to lower expression of MDC, PPH, PaO, and RCCR genes, while by enhancing the activity of SOD, CAT, APX, and GR enzymes, banana fruits treated with 150 mu M dopamine exhibited lower H2O2 accumulation. In addition, lower electrolyte leakage and MDA accumulation in banana fruits treated with 150 mu M dopamine demonstrated membrane integrity maintenance. Therefore, dopamine could be exogenously applied to alleviate chilling injury in banana fruits by enhancing the endogenous dopamine and glycine betaine accumulation and promoting the activity of ROS system activity.