Volatile compounds produced during ripening of strawberry are key determinants of fruit quality and consumer preference. Strawberry volatiles are largely esters which are synthesized by alcohol acyltransferases (AATs) and degraded by carboxylesterases (CXEs). Although CXE activity can have a marked influence on volatile contents in ripe strawberry fruits, CXE function and regulation in them are poorly known. Here, we report the biochemical and functional characterization of the fruit receptacle-specific and ripening-related carboxylesterase FanCXE1. The expression of the corresponding gene was found to be antagonistically regulated by auxins and abscisic acid, key hormones that regulate fruit growth and ripening in strawberry. In vitro, FanCXE1 was able to hydrolyze artificial ester substrates similar to those produced by ripe strawberry fruits. Transient suppression of the FanCXE1 gene by RNAi resulted in an increase of important volatile esters such as methyl hexanoate, methyl butanoate and ethyl hexanoate as well as a decrease of the alcohols hexenol and linanool. The results of this work enhance our understanding of the molecular basis for volatile syntheses and facilitate production of better flavored strawberry fruits by introduction of the relevant alleles into common cultivars.

中文翻译：

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草莓果实FanCXE1羧酸酯酶参与成熟过程中挥发性酯的分解代谢

草莓成熟过程中产生的挥发性化合物是水果质量和消费者偏好的关键决定因素。草莓挥发物主要是由醇酰基转移酶 (AAT) 合成并由羧酸酯酶 (CXE) 降解的酯。尽管CXE活性对成熟草莓果实的挥发物含量有显着影响，但CXE在其中的功能和调控知之甚少。在这里，我们报告了果实容器特异性和成熟相关的羧酸酯酶 FanCXE1 的生化和功能表征。发现相应基因的表达受到生长素和脱落酸的拮抗调节，这些激素是调节草莓果实生长和成熟的关键激素。在体外，FanCXE1 能够水解类似于成熟草莓果实产生的人造酯底物。RNAi对FanCXE1基因的瞬时抑制导致重要的挥发性酯如己酸甲酯、丁酸甲酯和己酸乙酯的增加以及醇类己烯醇和亚麻醇的减少。这项工作的结果增强了我们对挥发性合成的分子基础的理解，并通过将相关等位基因引入常见品种来促进生产风味更好的草莓果实。