Exogenous dopamine application ameliorates chilling injury and preserves quality of kiwifruit during cold storage

Abstract

This study investigated the mechanisms employed by exogenous dopamine application in alleviating chilling injury in kiwifruits during storage at 1 °C for 120 days. Our results indicated that dopamine treatment at 150 µM alleviated chilling injury in kiwifruits during storage at 1 °C for 120 days. By 150 µM dopamine application, higher SUMO E3 ligase (SIZ1) and target of rapamycin (TOR) genes expression accompanied by lower poly(ADP-Ribose) polymerase 1 (PARP1) and sucrose non-fermenting 1-related kinase 1 (SnRK1) genes expression was associated with higher salicylic acid, ATP, NADPH and proline accumulation in kiwifruits during storage at 1 °C for 120 days. In addition, higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity arising from higher phenols and flavonoids accumulation in kiwifruits treated with 150 µM dopamine could be ascribed to higher phenylalanine ammonia-lyase (PAL) enzyme activity. Additionally, lower endogenous hydrogen peroxide (H₂O₂) accumulation along with higher ascorbic acid accumulation in kiwifruits treated with 150 µM dopamine could be attributed to lower superoxide dismutase (SOD) along with higher catalase (CAT) enzymes activity. Moreover, lower phospholipase D (PLD) and lipoxygenase (LOX) genes expression in kiwifruits treated with 150 µM dopamine was accompanied with membrane integrity preservation as evidenced by lower electrolyte leakage and malondialdehyde (MDA) accumulation. Therefore, exogenous dopamine could be employed as a potential technique for alleviating chilling injury in kiwifruits during cold storage.

Keywords: Chilling injury; DPPH scavenging capacity; Dopamine; Kiwifruit; Membrane integrity.

Fig. 1

Chilling injury in kiwifruits treated with dopamine at concentrations of 0, 50, 100, 150, and 200 µM during storage at 1 °C for 120 days. Mean values (n = 3) are presented, and error bars denote standard errors of the means. Different letters indicate significant differences determined by Duncan’s test at P < 0.05.

Fig. 2

Electrolyte leakage (A) and malondialdehyde accumulation (B) in kiwifruits treated with dopamine at concentrations of 0 and 150 µM during storage at 1 °C for 120 days. Data displayed as mean values (n = 3), with error bars representing standard errors. Different letters indicate significant differences determined by Duncan’s test at P < 0.05.

Fig. 3

Gene expression levels of SIZ1 (A), TOR (B), PARP1 (C) and SnRK1 (D) in kiwifruits treated with dopamine at concentrations of 0 and 150 µM during storage at 1 °C for 120 days. Mean values (n = 3) are presented, and error bars denote standard errors of the means. Different letters indicate significant differences determined by Duncan’s test at P < 0.05.

Fig. 4

Activity of SOD (A) and CAT (B) enzymes along with H₂O₂ (C) and ascorbic acid (D) accumulation in kiwifruits treated with dopamine at concentrations of 0 and 150 µM during storage at 1 °C for 120 days. Mean values of n = 3 are displayed, with error bars indicating standard errors of the means. Different letters denote significant differences based on Duncan’s test at P < 0.05.

Fig. 5

PAL enzyme activity (A) along with accumulation of phenols (B) and flavonoids (C), and DPPH scavenging capacity (D) in kiwifruits treated with dopamine at concentrations of 0 and 150 µM during storage at 1 °C for 120 days. Data displayed as mean values (n = 3), with error bars representing standard errors. Different letters indicate significant differences determined by Duncan’s test at P < 0.05.

Fig. 6

Expression of PLD (A), and LOX (B) genes in kiwifruits treated with dopamine at 0 and 150 µM during storage at 1 °C for 120 days. Mean values (n = 3) are presented, with error bars indicating standard errors. Different letters denote significant differences based on Duncan’s test at P < 0.05.

Fig. 7

Accumulation of endogenous ATP (A), NADPH (B), salicylic acid (C) and proline (D) in kiwifruits treated with dopamine at concentrations of 0 and 150 µM during storage at 1 °C for 120 days. Mean values (n = 3) are presented, with error bars representing standard errors. Different letters indicate significant differences determined by Duncan’s test at P < 0.05.