# Adenosine triphosphate treatment affects strawberry fruit quality by regulating sugar and organic acid metabolism

## TL;DR

Applying ATP to strawberries helps maintain their quality by influencing sugar and acid levels, which can extend their shelf life.

## Contribution

This study reveals how ATP regulates sugar and organic acid metabolism in strawberries to preserve fruit quality.

## Key findings

- 1 mM ATP maintained fruit color, increased soluble solids, and reduced acidity in strawberries.
- ATP treatment enhanced enzyme activities and gene expression related to sugar metabolism.
- ATP promoted citrate and malate degradation while altering enzyme activities in organic acid metabolism.

## Abstract

Strawberries are characterized by distinctive flavors, sweet taste profiles, and abundant bioactive nutrients. However, they have a tender texture, and are prone to rapid ripening and softening post-harvest, leading to a loss of their commercial quality and marketability. Exogenous adenosine triphosphate (ATP) at appropriate concentrations can activate beneficial extracellular ATP signaling pathways that preserve agricultural product quality and extend shelf life during storage. However, research on the effects of exogenous ATP on strawberries is limited. Therefore, we aimed to analyze the regulatory effects of different concentrations of ATP on strawberry ripening by exploring its effects on sugar and organic acid metabolism in strawberries.

The effects of different concentrations of ATP on the quality, sugar metabolism, and organic acids of strawberry fruits stored at 4 °C for 15 days were examined.

The results demonstrated that 1 mM ATP effectively maintained fruit color, promoted the accumulation of soluble solids, reduced titratable acidity, and inhibited the decline in pulp firmness in sugar metabolism. Treatment with 1 mM ATP promoted the accumulation of glucose, fructose, and sucrose in strawberries, and enhanced the activities of acid invertase (AI), neutral invertase (NI), sucrose synthase (SS-s), sucrose cleavage enzyme (SS-c), and hexokinase (HK). It upregulated the expression of FaAI, FaSS1, FaSPS1, FaSPS2, FaNI, and FaHK3. In organic acid metabolism, 1 mM ATP treatment promoted the degradation of citrate and malate, and enhanced the activities of phosphoenolpyruvate carboxylase (PEPC) and NADP-dependent malic enzyme (NADP-ME), but reduced the activities of ferredoxin NADP-reductase-linked malate dehydrogenase (NAD-MDH) and citrate synthase (CS) enzymes. It also upregulated the gene expression of FaPEPC and FaNAD-IDH, and downregulated the expression of FaCS5.

Overall, 1 mM ATP treatment maintained strawberry fruit quality by regulating the expression of key genes and enzyme activities involved in sugar and organic acid metabolism in strawberries, thereby extending its shelf life.