The Endophytic Microbiota Drives Plant Growth and Flavonoid Dynamics in <i>Amana edulis</i> under Geographical Variation

The geographic origin influences endophytic bacterial communities in Amana edulis bulbs, impacting flavonoid accumulation. We analyzed bioactive components and endophytic microbiota in A. edulis bulbs from Anhui, Shandong, and Jiangsu provinces. Anhui samples exhibited significantly higher total flavonoid content and bulb weights compared to other regions. Bradyrhizobium spp. was identified as a biomarker genus in Anhui, positively correlating with total flavonoids, bulb fresh weight, catechin, and epicatechin levels. Metabolomic profiling revealed catechin and epicatechin as key differential flavonoids among the origins. Greenhouse pot experiments confirmed that inoculation with Bradyrhizobium sp. MA1 significantly enhanced bulb growth and flavonoid accumulation, notably increasing the catechin (37.99%) and epicatechin (12.03%) contents. This study reveals the microbial mechanism underlying geographical variations in A. edulis quality and provides a microbial-based strategy for sustainable cultivation and resource conservation.