Tolerance of potentially diazotrophic bacteria to adverse environmental conditions and plant growth-promotion in sugarcane

ABSTRACT

Sugarcane is one of the crops responsible for the high consumption of fertilizers in Brazil. To minimize this demand a sustainable alternative is to increase the studies to evaluate the beneficial effects of the relationship between plants/microorganisms, mainly plant growth-promoting bacteria. The objectives of this study were: a) to evaluate potentially diazotrophic bacteria isolates from sugarcane in adverse environmental conditions; b) inoculate these bacteria in sugarcane to evaluate their ability in plant growth-promotion. The study was carried in the Northeast of Brazil. Bacterial genera Burkholderia sp., Pantoea sp., Stenotrophomonas sp. and Enterobacter sp. were evaluated in different culture medium and later the bacterial isolates were inoculated in sugarcane evaluating the plant growth-promotion. Stenotrophomonas sp. and Pantoea sp. were tolerant to salinity and to different sources of carbon in acid medium and too tolerated high concentrations of pesticides and produced quorum sensing molecules (QS), but did not increase the dry matter production of sugarcane. Burkholderia sp. and Enterobacter sp. were more sensitive to salinity and pest control, but were more effective in plant growth-promotion. The tolerance of the bacteria to the adverse environmental conditions interfered negatively in the ability to plant growth-promotion.

KEYWORDS:

• Biological nitrogen fixation
• plant growth-promoting bacteria
• inoculating bacteria
• salt tolerance
• pesticide tolerance

Acknowledgments

Special thanks to the Laboratory of Genetics and Microbial Biotechnology of the Academic Unit of Garanhuns (UAG), Federal Rural University of Pernambuco (UFRPE), coordination and improvement of higher level personnel (CAPES), Foundation of protection of science and technology of the state of Pernambuco (FACEPE) and the National Council for Scientific and Technological Development (CNPQ).

Disclosure statement

No potential conflict of interest was reported by the authors.