Carotenoids are important natural pigments and essential for the coloration formation in plant petals. The difference in the accumulation of carotenoids always leads to the difference in flower coloration in O. fragrans. In this study, flower petals from different O. fragrans groups with different coloration were used. The critical genes and corresponding transcription factor (TF) candidates playing important role in carotenoid accumulation in petals were investigated through the integrated carotenoid profiles and transcriptomic analysis. We found the difference in the contents and compositions of carotenoids endow flower petal with diversified coloration, and expression levels of OfNCED3, OfDXS2, OfCCD1, OfGGPPS2, OfDXR3, OfBCH2, and OfCCD4 were critical factors modulating carotenoid accumulation. Further analysis showed that 61, 19, 21, 47, 16, 21, and 29 potential TF candidates with high Pearson correlation coefficients (|r|> 0.80) were but also for the first time speculated to interact with the promoter of OfNCED3, OfDXS2, OfCCD1, OfGGPPS2, OfDXR3, OfBCH2, and OfCCD4, respectively. In which, 17 TF candidates might bind to multiple gene promoters (>2) for affecting the carotenoid accumulation in O. fragrans petals. Furthermore, nine and one of OfCCD4 potential TFs presented similar and opposite expression pattern with OfCCD4, respectively, further indicating they might potentially participate in OfCCD4 expression regulation. Collectively, our data established the possible regulatory network between the critical genes and potential TF candidates and provided useful information for studying the underlying transcriptional mechanism of carotenoid accumulation in O. fragrans.

Carotenoids are important natural pigments and essential for the coloration formation in plant petals. The difference in the accumulation of carotenoids always leads to the difference in flower coloration in O. fragrans. In this study, flower petals from different O. fragrans groups with different coloration were used. The critical genes and corresponding transcription factor (TF) candidates playing important role in carotenoid accumulation in petals were investigated through the integrated carotenoid profiles and transcriptomic analysis. We found the difference in the contents and compositions of carotenoids endow flower petal with diversified coloration, and expression levels of OfNCED3, OfDXS2, OfCCD1, OfGGPPS2, OfDXR3, OfBCH2, and OfCCD4是调节类胡萝卜素积累的关键因素。进一步分析表明，61、19、21、47、16、21 和 29 个具有高 Pearson 相关系数 (|r|> 0.80) 的潜在 TF 候选者也首次被推测与OfNCED3、OfDXS2的启动子相互作用, OfCCD1, OfGGPPS2, OfDXR3, OfBCH2 , 和OfCCD4分别。其中，17 个候选 TF 可能与多个基因启动子 (>2) 结合，以影响O. fragrans花瓣中类胡萝卜素的积累。此外，9 个和 1 个OfCCD4潜在 TF 分别与OfCCD4呈现相似和相反的表达模式，进一步表明它们可能潜在地参与OfCCD4表达调控。总的来说，我们的数据在关键基因和潜在 TF 候选者之间建立了可能的调控网络，并为研究O. fragrans中类胡萝卜素积累的潜在转录机制提供了有用的信息。