Aliphatic esters: The missing link in fruit-frugivore olfactory communication?

脂肪族酯：水果与食果动物嗅觉交流中缺失的环节？

• 批准号: 397399570
• 负责人: Dr. Omer Nevo
• 金额: --
• 依托单位: Forschungsgruppe Evolutionsökologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/397399570?language=en
• 关键词: Aliphatic; esters; missing; link; fruit

Fruit odor has only recently been recognized as an important source of information to frugivores and potentially as a signaling system mediating the mutualistic interaction between plants and seed-dispersers. Most studies on fruit odor have focused on entire odor bouquets of ripe fruits and did not consider the roles of individual chemicals in conveying information to frugivores. An exception to this are ethanol and methanol, which are both byproducts of fruit maturation due to sugar fermentation or cell-wall degradation and have been suggested to be used by animals. Yet behavioral tests failed to document their function as attractants of frugivores. This may be the results of their deleterious effects. Aliphatic esters are ubiquitous in fruit odor and are responsible for most of what people perceive as fruity odor. They are often synthesized by flowers to increase their odor profiles and attract pollinators. Crucially, they are a direct biochemical product of alcohols such as methanol and ethanol. Many fruits actively synthesize aliphatic esters upon ripeness and alcohols are in fact a limiting factor in ester production. As a result, aliphatic esters in fruit odor are likely to be highly correlated with methanol and ethanol level and thus with fruit ripeness. The project will test the hypothesis that (a) fruit maturation is accompanied with increased levels of methanol and ethanol; (b) these alcohols are converted to aliphatic esters which are emitted as fruit odor, thus making ester levels in the odor an honest signal for fruit ripeness; and (c) that animals feeding on these fruits and dispersing their seeds are attracted to aliphatic esters and use them for fruit selection. The project will be conducted in Kibale National Park and Nagugabo Research Station, Uganda. It will incorporate chemical analysis of wild fruits and behavioral experiments with monkeys and, for the first time, wild African elephants. The results are expected to provide a high-resolution outlook on the evolutionary ecology of fruit odor and particularly aliphatic esters, as well as to develop methods which can be applied in many future studies in the field.

直到最近，水果气味才被认为是食果动物的重要信息来源，并且有可能作为介导植物和种子传播者之间互利相互作用的信号系统。大多数关于水果气味的研究都集中在成熟水果的整个气味香味上，没有考虑单个化学物质在向食果动物传递信息中的作用。乙醇和甲醇是一个例外，它们都是水果成熟过程中糖发酵或细胞壁降解的副产品，建议动物使用。然而行为测试未能证明它们作为食果动物引诱剂的功能。这可能是它们有害影响的结果。脂肪族酯在水果气味中普遍存在，并且是人们所感知的大部分水果气味的原因。它们通常由花朵合成，以增加气味并吸引传粉者。至关重要的是，它们是甲醇和乙醇等醇类的直接生化产品。许多水果在成熟时会主动合成脂肪族酯，而酒精实际上是酯类生产的限制因素。因此，水果气味中的脂肪族酯可能与甲醇和乙醇水平高度相关，从而与水果成熟度高度相关。该项目将检验以下假设：(a) 果实成熟伴随着甲醇和乙醇含量的增加； (b) 这些醇转化为脂肪族酯，并以水果气味的形式散发出来，从而使气味中的酯含量成为水果成熟度的真实信号； (c) 以这些水果为食并散布种子的动物会被脂肪族酯所吸引，并利用它们来选择水果。该项目将在乌干达基巴莱国家公园和纳古加博研究站进行。它将结合对野生水果的化学分析和猴子的行为实验，并首次对野生非洲象进行行为实验。研究结果预计将为水果气味，特别是脂肪族酯的进化生态学提供高分辨率的展望，并开发可应用于该领域许多未来研究的方法。