Colonization of Mycobacterium phlei in the rhizosphere of wheat grown under saline conditions

Authors: DILFUZA EGAMBERDIEVA

Abstract: One of the natural reservoirs of potentially human-pathogenic bacteria is believed to be the rhizosphere. The aim of the present work was to test nontuberculous mycobacterium Mycobacterium phlei MbP18 for its ability to colonize the rhizosphere of wheat and to evaluate its effect on plant growth under saline conditions. In competitive wheat root tip colonization assays, M. phlei MbP18 showed poor competitive colonization of the wheat rhizosphere compared to the reference strain. The strain produced lipase, amylase, cellulase, and pectinase and grew well in the presence of high salt (up to 4% NaCl) and at high temperatures (up to 40 °C). It was also able to utilize a wide range of carbohydrates for growth. The strain produced indole-3-acetic acid and proved to be very efficient in promoting a significant increase in the shoot and root of wheat under saline conditions. In conclusion, the results of this study indicate that M. phlei MbP18 has beneficial effects on plant growth under saline conditions through its ability to produce different biologically active compounds such as cell wall-degrading enzymes and the phytohormone auxin. However, its competitive colonization abilities in the rhizosphere are poor. In light of this observation, attempts should be made to manage the rhizosphere in order to prevent colonization of the rhizosphere by pathogens. This will help remove mycobacteria from habitats where humans or animals can be exposed.

Keywords: Mycobacterium phlei, colonization, enzymes, indole-3-acetic acid, plant growth stimulation

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