Pseudomonas spp. Isolated from the Rhizosphere of Angelica sinsensis (Oliv.) Diels and the Complementarity of Their Plant Growth-Promoting Traits

Pseudomonas has been revealed as an important member of plant probiotics, with its rich species diversity implying complementary plant growth-promoting (PGP) traits. However, information on Pseudomonas species in the microecology of Angelica sinensis and medicinal plants in general remains to be further investigated. This study examined the microecological characteristics, PGP traits, and their underlying molecular mechanisms of Pseudomonas. Filling this gap will provide an important reference for microbial community design centered on dominant functional bacterial genera. In this study, we characterized the microecological traits, PGP properties, and their underlying molecular mechanisms of Pseudomonas strains. Microbiome analysis identified Pseudomonas as the dominant genus in the rhizosphere and a core endophytic genus, exerting significant influences on both (path coefficients = 0.971, 0.872). Comparative phenomics suggested potential functional complementarity among different strains. Our observations revealed significant differentiation in PGP traits: P. umsongensis X08 showed exceptional performance in IAA and siderophore production (IAA: 1.24 mg/mL, siderophore halo diameter: 2.04 cm); P. frederiksbergensis X06 exhibited advantages in ACC deaminase activity and potassium solubilization; and P. allii X32 demonstrated high organic phosphorus solubilization capability (3.98 mg/L). Finally, genomic data revealed that P. allii X32 possesses a rich repertoire of PGP-related genes and metabolic pathways, providing a basis for establishing molecular mechanistic hypotheses for these traits. In summary, Pseudomonas strains from different species, which exhibit complementary probiotic functions without antagonism in the A. sinensis microecosystem, provide valuable microbial resources for the ecological cultivation of A. sinensis.