Exogenous ATP attenuated fermentative metabolism in postharvest strawberry fruit under elevated CO2 atmosphere by maintaining energy status

Elevated CO2 shows adverse effects in horticultural crops including off-flavor formation and carbohydrate consumption. Here, 1 mM adenosine triphosphate (ATP) was applied to strawberry fruit under 20 % CO2 atmosphere to investigate its regulation on fermentative and carbohydrate metabolism. The results showed that ATP treatment increased endogenous ATP content by 27 %, and delayed the decrease of energy charge under elevated CO2 atmosphere. Exogenous ATP showed no adverse effects on fruit firmness and color but attenuated the accumulation of acetaldehyde and ethanol, which were 72 % and 75 % lower in ATP+CO2-treated fruit compared CO2-treared fruit, respectively. The inhibition of fermentative metabolism resulted from the repression of pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH) activities, as well as FaADH expression. Meanwhile, ATP treatment also maintained carbohydrate levels under elevated CO2 atmosphere, with 6 %, 7 %, and 11 % more glucose, fructose and sucrose observed at the end of the storage period as compared with the CO2-treated group, respectively. The down-regulation of enzymes activities and gene expressions involved in sucrose catabolism and glycolysis may account for the inhibition of carbohydrate consumption. These results indicated that exogenous ATP might be a strategy to optimize elevated CO2 treatment to avoid its adverse effects.