Assessing the glyphosate tolerance of Lotus corniculatus and L. tenuis to perform rhizoremediation strategies in the Humid Pampa (Argentina)

MASSOT, F; SMITH, E; VITALI, VA; GIULIETTI, AM; MERINI, LJ

ECOLOGICAL ENGINEERING

ELSEVIER SCIENCE BV

Lugar: Oxford; Año: 2016 vol. 90 p. 392 - 398

0925-8574

The broad-spectrum herbicide glyphosate (N ?phosphonomethylglicine) is the most common pesticide used in the Humid Pampa,the main agricultural region in Argentina. According to agronomical practicesand topogeographical characteristics of the region, rhizoremediation arises asa promising technology to mitigate glyphosate impact on health andagroecosystems. Lotus corniculatus L. (birdsfoot trefoil) and Lotus tenuis Waldst et Kit. (=Lotus glaber Mill., narrowleaf trefoil)  were selected to carry out tolerance studiesas the starting point of a rhizoremediation process. L. corniculatus presented the highest root and foliar toleranceto glyphosate, corresponding to 5.0 mg kg-1 and 700 g ha-1respectively. The enzyme enolpyruvylshikimate-3-phosphate synthase (EPSP synthase) partial cDNA sequence andwhole plant shikimate accumulation assay were performed on L. corniculatus in order investigate tolerance mechanisms. No aminoacid substitution related to glyphosate tolerance was found on EPSP synthase cDNA sequence. The shikimateaccumulation study indicates that limited uptake and/or translocation of theherbicide is the most probable tolerance mechanism. Results obtained in thisstudy, plus the productive and adaptive advantages of L. corniculatus make it a valuable candidate to developrhizoremediation strategies.