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Author:
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Muñoz Robredo, P.; Rubio, P.; Infante, R.; Campos Vargas, R.; Manríquez, D.; González Agüero, M.; Defilippi, B. G.
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Abstract:
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Apricots are climacteric fruits with a high susceptibility to flesh softening and loss of flavor during
postharvest storage, and most of the ripening processes are regulated by ethylene, which also has an
effect on its own biosynthesis. To understand this process in apricot, inhibition of ethylene biosynthesis
and perception was performed for studying key genes involved in the ethylene biosynthetic pathway.
Apricots, cv. “Patterson”, were harvested with yellow-green ground color and immediately treated with
either the ethylene perception inhibitor 1-methyl cyclopropene (1-MCP) at 10 L L−1 or the ethylene
biosynthesis inhibitor aminoethoxyvinylglycine (AVG) at 1 g L−1. After treatment, quality and physiological
attributes such as firmness, color, total soluble solids, acidity, fruit weight, ethylene production
and respiration rates were evaluated every 2 d until they ripened at 20 ◦C. Gene expression analysis was
performed by quantitative polymerase chain reaction (qPCR). Both ethylene inhibitors were effective
in reducing ethylene production, respiration rate and fruit softening. Three 1-aminocyclopropane-1-
carboxylic-acid synthase (ACS) genes were characterized, but only the expression of ACS2 was highly
reduced by ethylene inhibition, suggesting a key role in ethylene synthesis at ripening. Contrarily, ACS1
and ACS3 showed a higher expression under ethylene inhibition suggesting that the corresponding genes
are individually regulated in a specific mode as observed in other climacteric fruits. Finally, changes in
1-aminocyclopropane-1-carboxylic-acid oxidase genes did not show a consistent pattern of ethylene
modulation. |