DNP and ATP regulate the pulp breakdown development in Phomopsis longanae Chi-infected longan fruit through modulating the ROS metabolism

Compared with the P. longanae-infected longan, the DNP-treated P. longanae-infected fruit represented a higher pulp breakdown index, a higher O(2)(–.) production rate, and a higher MDA content, but the lower activities of APX, SOD and CAT, the lower transcript levels of DlAPX6, DlSOD1, DlSOD2, DlSOD3 and DlCAT1, the lower values of AsA, GSH, flavonoid and total phenolics, a lower scavenging ability of DPPH radical, and a lower value of reducing power. Whereas, the ATP-treated P. longanae-infected samples showed the contrary results. The above findings indicated that the DNP-promoted the pulp breakdown in P. longanae-infected longan was because DNP weakened the capacity of scavenging ROS, raised the O(2)(–.) level, and accelerated the membrane lipids peroxidation. However, the ATP-suppressed the pulp breakdown in P. longanae-infected longan was because ATP improved the capacity of scavenging ROS, reduced the O(2)(–.) level, and reduced the membrane lipids peroxidation.