Astragalus membranaceus var. mongholicus (AMM) is a widely used medicinal plant in China, primarily cultivated in the northern regions; however, the selection and breeding of superior varieties remains underdeveloped. To scientifically assess the germplasm resources of AMM and facilitate its breeding, this study collected 33 germplasm samples from five provinces and conducted a comprehensive evaluation of their botanical traits, agronomic traits, quality traits, and powdery mildew resistance. The results indicated that, among the 18 botanical and agronomic traits, the Shannon–Wiener diversity index (H′) for quantitative traits was higher than that for qualitative traits, with the coefficient of variation ranging from 6.82% to 34.14%. The characterization of five flavonoids and eight saponins based on the established UPLC-Q-TOF/MS technique revealed that 13 compounds showed significant abundance variations across germplasms. Correlation analysis revealed that plants with robust above-ground growth usually have higher yields. Moreover, the number of compound leaflets was positively correlated with flavonoid content in the roots, whereas germplasms with smaller above-ground biomass and thinner roots exhibited higher saponin content. Based on the comprehensive scores (F-value), the top three germplasms were An-31, An-26, and An-28, which may serve as promising breeding materials. Cluster analysis grouped the 33 germplasms into five categories, including high-content and high-yield groups. Five germplasms exhibiting strong disease resistance were identified, with An-26 demonstrating the best performance in yield, quality, and resistance. Furthermore, a negative correlation was observed between powdery mildew resistance and flavonoid content in roots. This study will provide a foundation for the AMM breeding and selection.

Gray mold disease severely impacts the yield and quality of Panax notoginseng (Burkill) F. H. Chen ex C. Chow & W.G. Huang. In this study, a strain of Botrytis fabiopsis J. Zhang, G.N. Wu & G.Q. Li labeled as 3-3 was isolated from the leaves affected by gray mould disease of P. notoginseng, identified as a novel pathogen for this plant. Targeting the strain 3-3, an antagonistic bacterial strain X30 was isolated from the leaves of P. notoginseng and was preliminarily identified as Bacillus amyloliquefaciens (Fukumoto) Priest et al. through morphological and molecular biological analyses. The in vitro antifungal test showed that strain X30, at a concentration of 1 × 10⁸ CFU mL⁻¹, had an inhibition rate of 84.63% against the B. fabiopsis strain 3-3, and it exhibited broad-spectrum antifungal activity against other major pathogenic fungi of P. notoginseng, including Alternaria alternata (Fr.) Keissl., Rhizoctonia solani J.G. Kühn and others. Additionally, strain X30 was found to produce ammonia, fix nitrogen, secrete plant growth hormones, and release multiple hydrolytic enzymes, thus possessing both plant-growth-promoting and antimicrobial traits. In pot experiments, an X30 suspension at 1 × 10⁸ CFU mL⁻¹ achieved 61.04% control rate against B. fabiopsis. Using non-targeted metabolomics, compounds in the culture filtrate of strain X30 were analyzed, and two organic acid compounds with antimicrobial activity were identified. Among them, phenylpyruvic acid had an EC₅₀ value of 312 µg mL⁻¹ against pathogen 3-3, while 2,6-dihydroxybenzoic acid had an EC₅₀ value of 660 µg mL⁻¹. B. amyloliquefaciens X30 provides a theoretical basis for developing green and efficient biocontrol agents against gray mould in P. notoginseng.