【Objective】Beneficial plant inter-root microorganisms can enhance soil-crop interactions and promote crop growth. The aim of this paper is to investigate the growth promotion mechanism of strain LN01, a maize PGPR (Plant growth-promoting rhizobacteria) strain, on maize plants.【Method】Firstly, 16S rRNA and whole genomics sequencing were used to clarify the taxonomic status of strain LN01. Secondly, a pot experiment was conducted to validate the growth-promoting effects of strain LN01 on maize. Whole-genome data mining was performed to identify genes related to plant growth promotion, and carbon-nitrogen analyzers, molybdenum-antimony colorimetric methods, flame photometers, Salkowski colorimetric methods, and Chrome Azurol Sulfonate（CAS）blue qualitative detection plates were used to study the nitrogen fixation, phosphate solubilization, potassium solubilization, indole-3-acetic acid（IAA）production, and siderophore capabilities of strain LN01.【Result】The strain LN01 promoted biomass accumulation in maize plants and effectively increased soil nutrient content. Strain LN01 was identified as Leclercia adecarboxylata. There were gene clusters in strain LN01's genome for these, including iron acquisition（fhuBCDEF, afuABC, efeOBU, and fepCDG）, phosphate solubilization（pstABCS, phoABER, phnACDEFGHIJKLP, and ugpABCE）, biological nitrogen fixation（nirBCD, nasA, glnA, gltBD, and nrtABC）, potassium solubilization（kdpABC, kefBCFG, trkAH, and kup）and IAA biosynthesis（trpABSCFRGD）. The biogenic gene synthesis clusters for four secondary metabolites that promoted plant growth, including non-ribosomal peptide synthases（NRPS）, terpenes, thiopeptides, and aryl polyenes, were identified throughout the genome by antiSMASH analysis. Strain LN01 had the capacity of nitrogen fixation, phosphate solubilizing activity, potassium solubilizing capacity, and IAA production by 15.14, 58.33, 15.6 and 42.2 mg/L, respectively, as well as iron-carrier production capacity.【Conclusion】Strain LN01 possesses genes related to nitrogen-fixing and phosphorus-solubilizing, potassium solubilization, iron carrier production and IAA secretion, which helps maize plants fix nutrients and promote maize plant development.
