Figure 3

Overexpression of AtUCP1 increases mitochondrial uncoupled respiration, resulting in decreased cellular ATP content. (A) Time-course of respiration measurements on isolated mitochondria from WT and P07 plants. Malate (10 mM) and glutamate (5 mM) were added to the respiration medium to provide substrates for the electron transport chain. ADP (800 μM) was used to stimulate ADP-dependent respiration, and the ATP synthase inhibitor oligomycin (5 μM) was used to measure oxygen consumption due to uncoupled respiration. Maximum oxygen consumption was measured in the presence of FCCP (2 μM). (B) Average oxygen consumption of WT and P07 isolated mitochondria in the presence of ADP, oligomycin and FCCP. The leak ratio was calculated as the ratio between oxygen consumption in the presence of oligomycin and that in the presence of FCCP. (C) Decreased ATP levels in the L3, L4 and L5 leaves of the P07 transgenic line compared with WT. The data are representative of six biological replicates (n = 6). *p < 0.05 and **p < 0.1 compared with WT. Error bars, mean ± s.e.m.