Energy status of ripening and postharvest senescent fruit of litchi (Litchi chinensis Sonn.)

Abstract

BackgroundRecent studies have demonstrated that cellular energy is a key factor switching on ripening and senescence of fruit. However, the factors that influence fruit energy status remain largely unknown.ResultsHPLC profiling showed that ATP abundance increased significantly in developing preharvest litchi fruit and was strongly correlated with fruit fresh weight. In contrast, ATP levels declined significantly during postharvest fruit senescence and were correlated with the decrease in the proportion of edible fruit. The five gene transcripts isolated from the litchi fruit pericarp were highly expressed in vegetative tissues and peaked at 70 days after flowering (DAF) consistent with fruit ADP concentrations, except for uncoupling mitochondrial protein 1 (UCP1), which was predominantly expressed in the root, and ATP synthase beta subunit (AtpB), which was up-regulated significantly before harvest and peaked 2 days after storage. These results indicated that the color-breaker stage at 70 DAF and 2 days after storage may be key turning points in fruit energy metabolism. Transcript abundance of alternative oxidase 1 (AOX1) increased after 2 days of storage to significantly higher levels than those of LcAtpB, and was down-regulated significantly by exogenous ATP. ATP supplementation had no significant effect on transcript abundance of ADP/ATP carrier 1 (AAC1) and slowed the changes in sucrose non-fermenting-1-related kinase 2 (SnRK2) expression, but maintained ATP and energy charge levels, which were correlated with delayed senescence.ConclusionsOur results suggest that senescence of litchi fruit is closely related with energy. A surge of LcAtpB expression marked the beginning of fruit senescence. The findings may provide a new strategy to extend fruit shelf life by regulating its energy level.

Hydrogen sulfide delays leaf yellowing of stored water spinach (Ipomoea aquatica) during dark-induced senescence by delaying chlorophyll breakdown, maintaining energy status and increasing antioxidative capacity

“…Therefore, a higher ATP status can weaken the TCA cycle and result in the lower respiration rate. Taken together, we concluded that the decreased respiration rate in NaHS-treated samples might be attributed to the higher ATP level, which is also in accordance with the findings reported by Wang et al (2013), showing that the respiration rates could be inhibited by high ATP level during storage of litchi.…”

Oxidative Stress Associated with Chilling Injury in Immature Fruit: Postharvest Technological and Biotechnological Solutions

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CO2-driven changes in energy and fermentative metabolism in harvested strawberries

“…It is known that energy metabolism plays significant roles in the postharvest physiology of fruit and vegetables, and that ATP, ADP and AMP levels, as well as energy status, are affected by environmental factors, mainly by low oxygen levels (Saquet et al, 2001;Wang et al, 2013;Huang et al, 2014). A reduction of the cellular energy charge together with the accumulation of fermentative metabolites are generally considered to be common responses to hypoxia in aerobic organisms, including plants, and even a slight decrease in oxygen concentration provokes a drop in the cellular energy status (ATP/ADP ratio) (Geigenberger, 2003).…”