New insights into the chilling injury of postharvest white mushroom (Agaricus bisporus) related to mitochondria and electron transport pathway under high O2/CO2 controlled atmospheres

Abstract

Mitochondria and their electron transport pathway (ETP) might have a potential role in response to chilling stress. Notwithstanding, it is a novel area and the relative research is still in the early stages. In this study, we attempt to explore the explicit mechanisms of the 80% O2 + 20% CO2 treatment on alleviating chilling injury (CI) to white mushrooms based on the ETP and mitochondria, with natural air as the control.CI incidence, proportions of cytochrome pathway (CCP) and alternative pathway (AP), activities of key enzymes of CCP and AP, the relative gene expressions, mitochondrial structure and functions were investigated at 1 °C. The results reported that 80% O2 + 20% CO2 treatment prevented the occurrence of CI and retained the ATP yield. With regard to the ETP, the 80% O2 + 20% CO2 treatment restrained the decline in the proportion of CCP and boosted the proportion of AP through impacting the key enzymes and relative genes expressions. It also retarded mitochondria swelling and maintained higher levels of membrane fluidity and cytochrome c (Cyt c). Our results illustrated that 80% O2 + 20% CO2 dramatically alleviated the development of CI in white mushrooms, which could possibly be ascribed to the adjustment of ETP while retaining the structure and functions of the mitochondrion and the switching of its two conformations.