Flower odor is often essential for attracting pollinators, and this is especially true for species-specific mutualism such as the one between Ficus species and their pollinating wasps. Receptive figs emit a stage and species specific odor composed of a mix of volatile organic compounds (VOC) that is attractive to their pollinators. Histological studies suggest that the ostiolar bracts are the main locus of fig floral VOC synthesis. To confirm a major role of the ostiole in VOC synthesis, detect the genes involved in VOC synthesis and analyze differences between closely related species, we compare the transcriptomes of pre-receptive and receptive figs of two closely related species, F. hirta and F. triloba. The two species presented similar numbers of expressed genes and similar annotation, classification results, and their up-regulated unigenes belonged to similar biosynthetic pathways. However, phenylpropanoid and terpene synthesis were the main enriched VOC pathways in receptive figs of F. hirta while terpene and jasmonate synthesis were the main enriched VOC pathways in F. triloba. The shift in gene expression between pre-receptive and receptive figs was much more marked in the ostiolar bracts than in the flowers of F. hirta, and in the fig wall, confirming an important role of the ostiole in receptive fig odor emission. Only one unigene directly involved in VOC synthesis presented signatures of positive selection, further supporting that the source of interspecific receptive fig odor differentiation is based on gene regulation rather than on gene differentiation. Regulation based receptive fig odor differentiation between species suggests a potential for rapid evolution of this interspecific barrier.

花的气味通常对于吸引授粉媒介是必不可少的，对于物种特定的共生关系（例如榕属物种与其授粉的黄蜂之间的共生关系）尤其如此。无花果散发出阶段和物种特有的气味，这些气味由挥发性有机化合物（VOC）的混合物组成，对它们的传粉者具有吸引力。组织学研究表明，丁香片是无花果花VOC合成的主要场所。为了确认油sti素在VOC合成中的主要作用，检测与VOC合成有关的基因并分析密切相关物种之间的差异，我们比较了两个密切相关物种F.hirta和F.的无花果前体和无花果的转录组。三叶虫。这两个物种呈现相似数量的表达基因和相似的注释，分类结果，并且它们上调的单基因属于相似的生物合成途径。然而，苯丙和萜烯合成均的接受无花果主要富集的VOC途径F.古草而萜烯和茉莉酮酸酯的合成分别在主富集的VOC途径F.榆叶梅。前体无花果and片中接受前无花果和接受前无花果之间的基因表达变化比F. hirta的花明显得多。，以及在无花果壁上，证实了油sti素在无花果气味释放中的重要作用。仅一个直接参与VOC合成的单基因呈现出阳性选择的特征，进一步支持种间接受无花果气味分化的来源是基于基因调控而不是基因分化。物种之间基于调节的无花果气味的区别表明该种间障碍的快速发展潜力。