Genome sequence of Leclercia adecarboxylata QDSM01 with multiple plant growth promoting properties

Leclercia adecarboxylata QDSM01 is a plant growth-promoting bacterium isolated from the rhizosphere soil of maize. However, the relevant molecular mechanisms remain obscure. This study investigated the effect of Leclercia adecarboxylata QDSM01 on the seedling growth of maize, rice and soybean and uncovered the bacterium's biochemical characterization (biofilm, plant hormone secretion, nitrogen generation, phosphorus and potassium solubilization). In-depth analysis of the functional genes related to the biochemical characterization was conducted by complete genome sequence. Strain QDSM01 significantly promoted the seedling growth of maize and rice, but not soybean. The strain QDSM01 was identified as Leclercia adecarboxylata based on a comparison of 16 S rRNA gene sequences and complete genome sequence. The complete genome sequence indicated the strain comprised a 4,461,951 bp chromosome and 5 plasmids. Moreover, antiSMASH analysis revealed a total of four secondary metabolite gene clusters, consisting of putative non-ribosomal peptide synthase (NRPS), terpenoids, thiopeptides and arylpolyene. These gene clusters play an important role in promoting plant growth and resistance. Furthermore, the genes involved in biofilm formation, quorum sensing, chemotaxis, motility, indole-3-acetic acid production (IAA), siderophore, nitrogen generation, solubilization and uptake of phosphate and potassium were identified. Meanwhile, in vitro experiments were also performed to confirm these functions. In addition, the strong IAA production ability of strain QDSM01 was observed than other strains of Leclercia adecarboxylata. These results suggest that Leclercia adecarboxylata QDSM01 can serve as a biofertilizer that improves plant growth. This study will be helpful for further studies of Leclercia adecarboxylata on the mechanisms of plant growth promotion.