ABSTRACT

Aroma is a critical factor influencing consumer acceptability of ripe fruit. When fruit are eaten, the aroma travels retronasally from the mouth into the olfactory receptors located in the nose after exhaling. In kiwifruit (Actinidia spp.), terpene volatiles such as α-terpinolene and 1,8-cineole have been shown to contribute to the characteristic aroma of ripe fruit. Notably, 1,8-cineole contributes a key floral/eucalyptus note to the aroma of ripe A. chinensis ‘Hort16A’ kiwifruit, based on sensory descriptive and discriminant analysis. Emission of α-terpinolene and 1,8-cineole in kiwifruit is induced by ethylene, and production peaks when fruit are at eating ripeness. Two monoterpene synthase TPS-b family genes have been isolated from the fruit of A. arguta and A. chinensis that produce α-terpinolene and 1,8-cineole, respectively. Here we discuss terpene volatiles with respect to fruit aroma and consumer sensory evaluation, analyze the gene structure and conserved motifs of TPS-b genes in published kiwifruit genomes and then construct a transcriptional regulatory network based on Actinidia TPS-b. These data provide further insights into the potential molecular mechanisms underlying signature monoterpene synthesis to improve flavor in kiwifruit.

摘要

香气是影响消费者对成熟水果接受度的关键因素。吃水果时，香气会在呼气后从口腔逆鼻传播到位于鼻子中的嗅觉感受器。在猕猴桃（猕猴桃属）中，萜烯挥发物如 α-萜品油烯和 1,8-桉树脑已被证明有助于成熟水果的特征香气。值得注意的是，基于感官描述和判别分析，1,8-桉树脑对成熟的A. chinensis 'Hort16A' 奇异果的香气做出了关键的花香/桉树香调。奇异果中 α-萜品油烯和 1,8-桉树脑的释放是由乙烯诱导的，果实在食用成熟时产生高峰。已从A. arguta的果实中分离出两个单萜合酶 TPS-b 家族基因和A. chinensis分别产生 α-萜品油烯和 1,8-桉树脑。在这里，我们讨论了萜类挥发物对水果香气和消费者感官评价的影响，分析了已发表的猕猴桃基因组中 TPS-b 基因的基因结构和保守基序，然后构建了基于猕猴桃TPS-b 的转录调控网络。这些数据进一步深入了解了标志性单萜合成的潜在分子机制，以改善猕猴桃的风味。