Phosphorus addition promotes the growth by improving microbial function and recruiting Cupriavidus basilensis-10 strain in rhizosphere soil of Phellodendron chinense Schneid seedlings

Phosphorus (P) influences the soil nutrient cycle, microbial function and plant growth, but the mechanism of P additions promoting the growth of Phellodendron chinense Schneid is not documented. In this study, CK (0 g·m −2 ), P5 (5 g·m −2 ), P10 (10 g·m −2 ) and P15 (15 g·m −2 ) treatments were conducted, and the biomass, photosynthetic pigment, soil microenvironment and core bacterial function were investigated. Results showed that P additions reduced soil pH and organic carbon contents, decreased bacterial α -diversity and microbial network complexity, whereas enhanced ammonium nitrogen, nitrate nitrogen and available phosphorus contents, along with acid phosphatase and catalase activities, strengthened fungal network stability and increased the absolute abundance of Cupriavidus taxa, ultimately improved the pigment contents and biomass of seedlings, which the P10 treatment was the best. P10 treatment upregulated the expressions of abfA , amyA , manB , xylA , rbcL , smtA , nxrA , nifH , amoA1 , nasA , gcd and phnK genes, boosted the contents of estrone, estriol, 17α-hydroxyprogesterone, docasahexaenoic acid and prostaglandin F2α, simultaneously decreased nucleotide-related metabolite contents in rhizosphere soil. Furthermore, Cupriavidus basilensis -10 identified as keystone strain enhanced the AP content and ACP activity in vitro, increased the photosynthetic pigment and leaf AP contents, plant height and biomass of P. chinense Schneid seedlings. These findings indicate that P10 treatment promotes the growth by improving microbial function and recruiting Cupriavidus basilensis -10 strain in rhizosphere soil of P. chinense Schneid seedlings. • P additions promoted the growth of P. chinense Schneid seedlings, with P10 treatment showing the best effect. • P additions reduced the microbial network complexity and enhanced Cupriavidus abundance in rhizosphere soil. • P10 treatment upregulated gene expressions of nutrient cycle and key metabolite contents in rhizosphere soil. • Isolated Cupriavidus basilensis -10 strain improved the biomass of P. chinense Schneid seedlings.