Specific binding of NTP to MaDORN1.19 enhances cold tolerance of postharvest banana fruit during storage

Abstract

As the first plant receptor gene for extracellular ATP (eATP), DORN1, could play a key role in responding low temperature in plants. This study investigated the interactions of the banana receptor, MaDORN1.19, with nucleoside triphosphates (NTPs) to affect chilling injury (CI) of banana fruit stored for 8 d at 6 °C. Molecular simulation found that ATP or GTP exhibited more stable interactions with MaDORN1.19 according to the lower libDOCK scores and more amino acid residues in binding pockets compared with CTP and UTP. Results indicated that the CI indices of ATP or GTP-treated banana fruit were 1.6 and 1.79 whereas those of UTP or CTP-treated and non-treated fruit were 2.11, 2.07 and 2.22, respectively. Furthermore, application of ATP or GTP significantly maintained a low level of eATP, inhibited the accumulation of malondialdehyde and enhanced the antioxidant ability of banana fruit during cold storage. Based on the CI extent, binding ability of NTP to MaDORN1.19 and the NTP treatment effect, it can be suggested that ATP or its analogs could specifically bind to MaDORN1.19 to maintain eATP homeostasis, retard oxidative damage, ensure membrane integrity and, thus, attenuate chilling injury of banana fruit during cold storage. This study provided new insights of eATP in the CI occurrence of banana fruit during storage at low temperature.