Visualizing the Effect of Cultivation Regimes on Carotenoid Metabolism and Its Interplay with Endophytic Bacterial...

As the demand for saffron expands, it is urgent to find suitable local cultivation regimes to improve saffron quality. Two-segment cultivation was proposed in the Yangtze River Delta of China. However, the soil- and water-free cultivation method may alter the grown microenvironment, thereby affecting the endophytic bacterial communities and its interactions with bioactive compounds. Herein, a comprehensive strategy based on nontargeted spatial metabolomics and high-throughput sequencing was established. Mass spectrometry imaging results showed that the crocins accumulated in the stigma part of saffron with the two-segment cultivation method. Flavor components like safranal and picrocrocin accumulated in the stigma and style part of saffron with a traditional outdoor cultivation method. Additionally, Citrobacter showed a positive correlation with the contents of crocin, which might be attributed to the elevated gene expression of ALDH, UGT74AD1, and UGT91P3. The strategy established might provide a valuable foundation for understanding cultivation regimes in nontraditional saffron-growing regions.