Screening, Identification and Growth-Promotion Products of Multifunctional Bacteria in a Chinese Fir Plantation

This research was aimed to screen and identify multifunctional phosphorusdissolving bacteria of a Chinese fir (Cunninghamia lanceolata) plantation and study its phosphorusdissolving characteristics in order to provide strain resources and a theoretical basis for developing the appropriate bacterial fertilizer of a Chinese fir plantation.(1) Thirteen phosphorus-dissolving bacteria were isolated and screened in total, and P5 (195.61 mg L����1) had the strongest capacity of phosphorus-solubilized. Five phosphorus-dissolving bacteria were provided with nitrogenase activity, and the highest activity of nitrogenase was P10 and P5 (71.90 C2H4 nmol mL����1 h����1 and 71.00 C2H4 nmol mL����1 h����1, respectively). Four strains were provided with ACC deaminase activity, and the highest activity of ACC deaminase was P5 and P9, (0.74 mol mg����1 h����1 and 0.54 mol mg����1 h����1, respectively). Most strains could secrete IAA, and three strains of bacteria had a strong secretory ability, which could secrete IAA with a concentration greater than 15 mg mL����1, and P5 was 18.00, P2 was 17.30, P6 was 15.59 (mg mL����1). P5 produced carriers of iron better than others, and the ratio of the diameter of the iron production carrier ring to the diameter of the colony was 1.80, respectively, which was significantly higher than other strains. Combining all kinds of factors, P5 multifunctional phosphorus-dissolving bacteria were screened for eventual further study. (2) Strain P5 was identified as Burkholderia ubonensis, based on the colony characteristics, physiological and biochemical tests, 16SrDNA sequence analysis and phylogenetic tree construction. Conclusion P5 has a variety of high-efficiency growth-promoting capabilities, and the ability to produce IAA, ACC deaminase activity and siderophore performance are significantly higher than other strains, which had great potential in the development of microbial fertilizer.