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Beijerinckia derxii releases plant growth regulators and amino acids in synthetic media independent of nitrogenase activity
Author(s) -
Thuler D.S.,
Floh E.I.S.,
Handro W.,
Barbosa H.R.
Publication year - 2003
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2003.02047.x
Subject(s) - nitrogenase , putrescine , biology , bacteria , spermidine , biochemistry , azotobacteraceae , amino acid , nitrogen fixation , ethylene , enzyme , genetics , catalysis
Aims: This study aims at evaluating the ability of Beijerinckia derxii , a free‐living nitrogen (N)‐fixing bacterium frequently isolated from tropical soils, to release certain plant growth regulators [indoleacetic acid (IAA), ethylene, polyamines] and amino acids into the growth medium. Methods and Results: The production of those substances was compared using both cultures in which nitrogenase was active (N‐free medium) and cultures in which nitrogenase was repressed (combined‐N cultures). Those cultures were grown under agitation and in absence of agitation. Total IAA production was higher in agitated, N‐free cultures but specific production was greater in combined‐N cultures under agitation. Putrescine and spermidine were detected under all conditions tested. Ethylene was produced in both N‐free and combined‐N cultures. A greatest diversity of amino acids was released in N‐free cultures. Conclusions: There was no inhibition of the production of the analysed substances under conditions where nitrogenase was inactive. Significance and Impact of the Study: Beijerinckia derxii is potentially a producer of plant‐active substances; its presence in the natural environment suggests that this bacterium may contribute to the development of other living organisms.