Possible non-target effects of the widely-used, non-selective herbicide glyphosate were examined in six cyanobacterial strains, and the basis of their resistance was investigated. All cyanobacteria showed a remarkable tolerance to the herbicide up to millimolar levels. Two of them were found to possess an insensitive form of glyphosate target, the shikimate pathway enzyme 5-enol-pyruvyl-shikimate-3-phosphate synthase. Four strains were able to use the phosphonate as the only phosphorus source. Low uptake rates were measured only under P-deprivation. Experimental evidence for glyphosate metabolization was obtained also in strains apparently unable to use the phosphonate. Results suggest that various mechanisms may concur in providing cyanobacterial strains with herbicide tolerance. Data account also for their widespread ability to metabolize the phosphonate. However, such capability seems limited by low cell permeability to glyphosate, and is promptly repressed when inorganic phosphate is available.
Biochemical bases for a widespread tolerance of cyanobacteria to the phosphonate herbicide glyphosate
FORLANI, Giuseppe;
2008
Abstract
Possible non-target effects of the widely-used, non-selective herbicide glyphosate were examined in six cyanobacterial strains, and the basis of their resistance was investigated. All cyanobacteria showed a remarkable tolerance to the herbicide up to millimolar levels. Two of them were found to possess an insensitive form of glyphosate target, the shikimate pathway enzyme 5-enol-pyruvyl-shikimate-3-phosphate synthase. Four strains were able to use the phosphonate as the only phosphorus source. Low uptake rates were measured only under P-deprivation. Experimental evidence for glyphosate metabolization was obtained also in strains apparently unable to use the phosphonate. Results suggest that various mechanisms may concur in providing cyanobacterial strains with herbicide tolerance. Data account also for their widespread ability to metabolize the phosphonate. However, such capability seems limited by low cell permeability to glyphosate, and is promptly repressed when inorganic phosphate is available.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
