Potential biocontrol and plant growth promotion of an endophytic bacteria isolated from Glycyrrhiza uralensis seeds

Abstract

Abstract Background Endophytic bacteria have been demonstrated to be one of the most potentially important biocontrol agents for their efficiently improved plant growth and protection of host plants from infection by phytopathogens. Results Nine strains of endophytic bacteria isolated from Glycyrrhiza uralensis Fisch. (G. uralensis) seeds were screened for the inhibitory effect against 5 fungal phytopathogens by using dual culture method. Among which, the isolate FT2 showed the highest percentage of inhibition to all the test fungal phytopathogens. Detached root assay showed that FT2 significantly reduced disease index and rotted area on Angelica sinensis root slices caused by Fusarium acuminatum. FT2 also exhibited multiple plant growth promotion traits by qualitative analytical method. Based on phenotypic, physiological and biochemical characterization and genotypic characterization, the FT2 strain was identified as Stenotrophomonas rhizophila. Application of strain FT2 reduced the disease index of Cucumber Fusarium Wilt, and the biocontrol effect was equal to chemical fungicide, carbendazim. Moreover, strain FT2 increased the plant height, stem diameter, leaf number and fresh weight of cucumber seedlings and the activities of the defense-related enzymes including phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase. In addition, strain FT2 could promote seed germination and seedling growth of G. uralensis and increase enzyme activities, available nutrient contents and bacterial count in G. uralensis rhizosphere soil. Conclusions The results demonstrated that the strain FT2 could be used to develop environmentally friendly microbial products to improve the activity against pathogenic and promote plant growth.

Keywords

• Stenotrophomonas rhizophila
• Biocontrol
• Growth promoting
• Glycyrrhiza uralensis seeds
• Endophytic bacteria