Correlation analysis of aroma, rhizosphere microbiota, and active constituents in Qianhu from different origins

This study aimed to investigate the differences and intrinsic relationships among aroma components, rhizosphere microorganisms, and active constituents of Qianhu from the geo-authentic production area of Ningguo, Anhui Province, and other production areas, including Guizhou and Chongqing.

Gas chromatography-ion mobility spectrometry (GC-IMS) was used to analyze aroma components, and relative odor activity value (ROAV) analysis was applied to identify key aroma compounds and potential markers for origin discrimination. High-throughput sequencing was used to characterize bacterial and fungal communities in rhizosphere soils. High-performance liquid chromatography (HPLC) was performed to determine the contents of praeruptorin A (PA) and praeruptorin B (PB). Correlation analysis was further conducted to clarify the relationships among aroma components, rhizosphere microorganisms, and active constituents.

A total of 69 volatile components were identified. Among them, 10 key aroma compounds with ROAV values greater than 1 showed significantly higher ROAV values in Ningguo samples than in samples from other regions, indicating a pronounced aroma advantage. The dominant bacterial taxa in the rhizosphere of the geo-authentic production area were norank_o__Vicinamibacterales and norank_o__Terriglobales, while the dominant fungal taxa were Didymella and Neocosmospora. Active constituent analysis showed that sample G2 from Guizhou had the highest PA content (1.76%), whereas sample ND4 from Ningguo had the highest PB content (0.25%). Correlation analysis revealed that within the bacterial community, Gaiellales showed positive correlation trends with multiple components and exhibited the broadest range of associations. Within the fungal community, Neocosmospora and Bisifusarium showed positive correlation trends with multiple aroma components, suggesting potential roles in flavor formation. Among bacteria, norank_f__Vicinamibacteraceae showed a positive correlation trend with PA, while norank_o__Rokubacteriales showed a positive correlation trend with PB. Among fungi, Neocosmospora showed a negative correlation trend with PA and a positive correlation trend with PB. Regarding aroma components, heptaldehyde-M showed a positive correlation trend with PA, while unidentified compound 6 showed a negative correlation trend with PA and a positive correlation trend with PB.

Qianhu from the geo-authentic region (Ningguo) showed certain advantageous trends in aroma intensity and key microbial taxa. The accumulation of PA and PB may be associated with distinct microbial functional groups. These findings provide preliminary exploratory insights into the microecological mechanisms underlying the geo-authenticity formation of Qianhu.