Diversity and plant growth promoting potential of gut culturable bacteria in third-instar nymphs of Eocanthecona furcellata（Wolff）

【Objective】 To study the composition of culturable bacteria in the gut of nymphs of the Eocanthecona furcellata（Wolff），and analyze the growth promoting characteristics of the strains，so as to provide scientific basis and research materials for the study of the relationship among the gut bacteria of E. furcellata，hosts and plants，as well as the development and utilization of probiotic. 【Method】 The traditional bacterial isolation and culture method was used to isolate and purify the gut bacteria of nymphs of E. furcellata. The isolated gut bacteria were classified and identified by bacterial morphology，staining reaction，physiological and biochemical tests and 16S rDNA sequence analysis，and qualitative analysis of the growth promoting potential of the strains was conducted by determining their nitrogen fixation，phosphorus solubilization，indoleacetic acid production and siderophore production ability. 【Result】 A total of 11 strains of bacteria were isolated from the gut of nymphs of E. furcellata，the 11 strains of gut bacteria included 8 Gram-positive bacteria and 3 Gram-negative bacteria strains. The cell morphology of 3 strains was short rod-shaped，1 stain was globular，and 7 strains were rod-shaped. and the 11 strains of gut bacteria bebonged to 2 phyla，2 classes，3 orders，4 families and 4 genera. The dominant phylum，class，order，family and genus were Firmicutes（85.67%），Bacilli（85.67%），Lactobacillales （75.80%），Enterococcaceae（75.80%），Enterococcus（75.80%）respectively. At the species level，E. faecalis（75.80%）， Bacillus subtilis（9.17%），Morganella morganii（6.51%），Serratia nematodiphila（4.49%），S. marcescens（3.30%），B. thuringiensis（0.28%），B. velezensis（0.27%）and B. altitudinis（0.18%） were identified as abundant bacterial species. Plant promoting characterization of the 11 isolated strains showed that 2 strains of Serratia had the highest promotion potential with 4 plant growth promoting properties：nitrogen fixation，phosphorus solubilization，indoleacetic acid production and siderophore production，followed by 1 strain of Morganella with 3 plant growth promoting properties：phosphorus solubilization，indoleacetic acid production and siderophore production. 【Conclusion】 The culturable bacterial species in the gut of nymphs of E. furcellata are relatively abundant，and 11 bacterial strains isolated from the gut have different degrees of growth promoting properties.