Characterization of a versatile rhizospheric organism from cucumber identified as Ochrobactrum haematophilum.

Several rhizobacteria play a vital role in promoting plant growth and protecting plants against fungal diseases and degrading pesticides in the environment. In this study, a bacterial strain, designated H10, was isolated from the rhizosphere at Laixi in Shandong Province, China, and was identified as Ochrobactrum haematophilum based on API 20 NE tests and 16S rRNA gene sequence analysis. The plant growth-promoting characteristics of the strain were further characterized, and the results showed that strain H10 produces siderophore, indol-3-acetic (IAA) and solubilized phosphate but lacks 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Inoculation with the strain was found to significantly increase (p < 0.05) the growth of cucumber in pot experiments. Strain H10 was assessed in vitro for antagonism against several pathogenic fungi and showed high antifungal activity. The cell-free culture filtrates, which had high extracellular chitinase, β-1,3-glucanase and protease activities, could inhibit the growth of all pathogenic fungi tested, indicating that growth suppression was partly due to extracellular antifungal metabolites present in the culture filtrates. Changes in hyphal morphology were observed in phytopathogenic fungi after treatment with the culture filtrates. Additionally, strain H10 was able to degrade 80%, 85% and 58% of the pesticides chlorpyrifos, β-cypermethrin and imidacloprid, respectively, within 60 h in liquid culture. The inoculation of strain H10 into soil treated with 100 mg kg(-1) of the three pesticides accordingly resulted in a higher degradation rate than in noninoculated soils. These results highlight the potential of this bacterium for use as a biofertilizer and biopesticide and suggest that it may provide an alternative to the use of chemical fertilizers and pesticides in agriculture. Additionally, it may represent a bioremediation agent that can remove contaminating chemical pesticide residues from the environment.

Zhao L ，Teng S ，Liu Y 《-》

Bacillus strains isolated from rhizosphere showed plant growth promoting and antagonistic activity against phytopathogens.

Seven bacterial isolates screened from rhizosphere of common bean growing at Uttarakhand Himalaya showed potential plant growth promoting (PGP) and antagonistic activities. Based on 16S rRNA gene sequence the isolate BPR7 was identified as Bacillus sp. BPR7. The strain BPR7 produced IAA, siderophore, phytase, organic acid, ACC deaminase, cyanogens, lytic enzymes, oxalate oxidase, and solubilized various sources of organic and inorganic phosphates as well as potassium and zinc. Strain BPR7 strongly inhibited the growth of several phytopathogens such as Macrophomina phaseolina, Fusarium oxysporum, F. solani, Sclerotinia sclerotiorum, Rhizoctonia solani and Colletotricum sp. in vitro. Cell-free culture filtrate of strain BPR7 also caused colony growth inhibition of all test pathogens. PGP and antifungal activities of Bacillus sp. BPR7 suggest that it may be exploited as a potential bioinoculant agent for P. vulgaris.

Kumar P ，Dubey RC ，Maheshwari DK 《-》

[Isolation and identification of a strain DN2 degrading nicotine].

Yuan YJ ，Lu ZX ，Huang LJ ，Lv FX ，Bie XM ... -  《-》

New bacterial strain of the genus Ochrobactrum with glyphosate-degrading activity.

Hadi F ，Mousavi A ，Noghabi KA ，Tabar HG ，Salmanian AH ... -  《-》

[Isolation of moniliformin-degrading bacterium Ochrobactrum sp. and analysis of its functional properties].

Chen W ，Zhang H ，Li J 《-》