Avocados (Persea americana Mill.) are climacteric fruits, the ripening of which during postharvest at room temperature is strongly ethylene dependent. However, the role of other phytohormones in the modulation of postharvest ripening of avocados is still poorly understood. The optimal ripening state of avocados is attained a few days after harvest depending on the genotype, growing region and initial maturity stage of the fruit, and cold temperature storage is commonly used to delay this process. Here, we hypothesized that the ripening of avocados at room temperature may be governed not only by ethylene, but also by other phytohormones. With this aim, we analyzed the hormonal profiling of avocados subjected to either 4 °C and 25 °C during 10 days of postharvest. A biphasic response was observed during postharvest ripening of avocados at room temperature. While ethylene alone appeared to govern fruit ripening during the first transfer from cold to room temperature, a complex hormonal interplay occurred during ripening of avocados leading to a progressive fruit softening at room temperatures. Aside from ethylene, auxin, gibberellins, jasmonates and ABA appeared to be involved in avocado fruit ripening during postharvest at room temperature. Cold storage for a period of 10 days inhibited this hormonal response related to ripening. Furthermore, avocados stored at cold temperatures underwent a quick response in order to tolerate cold stress leading to changes in endogenous ABA and jasmonates. We conclude that a complex hormonal interplay, rather than ethylene alone, modulates postharvest ripening of avocados and that cold storage can effectively be employed as a technique to prevent avocados from a rapid ripening thanks to the cold stress tolerance mechanisms deployed by fruits through multiple hormonal regulation.

中文翻译：

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鳄梨果实成熟和冷驯化调节中的激素相互作用

鳄梨 (Persea americana Mill.) 是更年期水果，其在室温下采后的成熟过程强烈依赖于乙烯。然而，其他植物激素在鳄梨采后成熟调控中的作用仍知之甚少。根据果实的基因型、生长区域和初始成熟阶段，鳄梨在收获后几天达到最佳成熟状态，通常使用低温储存来延迟这一过程。在这里，我们假设鳄梨在室温下的成熟不仅受乙烯控制，还受其他植物激素的控制。为此，我们分析了在收获后 10 天内经受 4 °C 和 25 °C 的鳄梨的激素分析。在室温下鳄梨的采后成熟过程中观察到双相反应。虽然在从冷到室温的第一次转移过程中，乙烯似乎单独控制了果实的成熟，但在鳄梨成熟过程中发生了复杂的激素相互作用，导致果实在室温下逐渐软化。除了乙烯，生长素、赤霉素、茉莉酸和 ABA 似乎与室温下收获后的鳄梨果实成熟有关。冷藏 10 天会抑制这种与成熟相关的激素反应。此外，在低温下储存的鳄梨经历了快速反应，以耐受导致内源性 ABA 和茉莉酸改变的冷应激。我们得出结论，一个复杂的激素相互作用，而不是单独的乙烯，