Abstract

The purpose of this study was to assay the cultivable microorganisms of Davidia involucrate in rhizosphere soil and to analyze their diversity using colony and individual morphology and genetic profiling methods. A total of 118 strains were obtained after colony characterization and a microscopic examination, including 52 bacteria strains, 27 actinomycetes strains and 39 fungi strains. Fifty-seven (57) of these strains were randomly selected for rDNA analysis and phylogenetic identification, including 23 rhizobaceria isolates, 29 fungi isolates, and five streptomyces isolates. The selected isolates were accurately identified at the genus level with consistent results using a morphology examination and phylogenetic identification. From the study, we concluded the following: (1) Bacillus, Lactobacillus, Azotobacter, and Streptomyces are predominant microorganisms of D. involucrate in rhizophere soil and Bacillus is a dominant rhizobacteria that might have potential in host growth promotion; (2) the physiological activity of dovetree could significantly influence the microorganism biomass of the rhizophere soil; and (3) the dovetree is a highly complex rhizosphere ecosystem, and additional research on this topic should be carried out in the future.

Key words: Rhizosphere microorganism, Davidia involucrate, plant growth promotion, soil.

Abbreviation

PGPR, plant growth promoting rhizobacteria; PCR, polymerase chain reaction; DGGE, denaturing gradient gel electrophoresis; SSCP, single strand conformation polymorphism; RFLP, restriction fragment length polymorphisms; T-RFLP, terminal restriction fragment length polymorphisms; q-PCR, quantitative PCR; NA, nutrition agar; ISSA , inorganic salt starch agar; PDA , potato dextrose agar; CFU, colony forming units; BLAST, Basic local alignment search tool; NCBI, National Center of Biotechnology Information.