The combined effects of climate, soil, and rhizospheric microorganisms determine the quality and suitable production zones of Stellaria dichotoma L. var. lanceolata Bge. in China

Stellaria dichotoma L. var. lanceolata Bge. (S. lanceolata) is a psammophytic plant endemic to the northwest region of China and has now developed into a cultivated economic crop. It is the original plant species used in traditional Chinese medicine as Yinchaihu. Recently, the lack of scientifically guided production zoning has exacerbated the arbitrary introduction and expansion of S. lanceolata cultivation, resulting in significant changes to its habitat and quality. This study utilizes distribution data of wild S. lanceolata along with data from 33 environmental factors to analyze the primary habitat factors influencing the species' distribution using the Maxent model, simulating both current and future suitable production zones. Additionally, amplicon sequencing was employed to investigate changes in rhizospheric soil microorganisms across different cultivation sites and years. Furthermore, metabolomics, near-infrared spectroscopy, and the quantification of active ingredient content were used to assess the effects of various suitable zones on S. lanceolata. The migration trends of S. lanceolata toward the central and eastern regions of Inner Mongolia revealed that elev, bio_4, bio_13, bio_11, and S_clay are the primary ecological and soil factors influencing suitability zoning, contributing a cumulative rate of 80.5%. The rhizosphere microbial environment shifted significantly from high to medium suitability habitats. As cultivation duration increased, the diversity of fungi and bacteria and the functional genera within the rhizosphere exhibited significant changes. Notably, there were substantial alterations in metabolic processes and substance accumulation during the transition from high to medium and low suitability zones, resulting in the identification of 281 and 370 differential metabolites, respectively. Additionally, the near-infrared spectral characteristics and active ingredient content of S. lanceolata in high suitability zones displayed distinct specificity. In particular, the contents of total flavonoids (2.772 mg·g−1), dichotomines B (0.057 mg·g−1), and quercetin-3-O-β-D-glucoside (0.312 mg·g−1) were notably higher, with the overall quality score surpassing that of other suitable zones. This study revealed the key climatic, soil, and rhizosphere microbial environmental factors influencing the quality formation of S. lanceolata and the selection of suitable production zones, offering guidance for sustainable development and production zone planning.