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

FRANCISCO MASSOT; ANA MARÍA GIULIETTI; MARÍA EMILIA SMITH; LUCIANO JOSÉ MERINI; VICTORIA ANDREA VITALI

ECOLOGICAL ENGINEERING

ELSEVIER SCIENCE BV

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

0925-8574

The broad-spectrum herbicide glyphosate (N ? phosphonomethylglicine) is the most common pesticideused in the Humid Pampa, the main agricultural region in Argentina. According to agronomical practicesand topogeographical characteristics of the region, rhizoremediation arises as a promising technologyto mitigate glyphosate impact on health and agroecosystems. Lotus corniculatus L. (birdsfoot trefoil) andLotus tenuis Waldst. et Kit. (=Lotus glaber Mill., narrowleaf trefoil) were selected to carry out tolerancestudies as the starting point of a rhizoremediation process. L. corniculatus presented the highest rootand foliar tolerance to glyphosate, corresponding to 5.0 mg kg−1and 700 g ha−1respectively. The enzymeenolpyruvylshikimate-3-phosphate synthase (EPSP synthase) partial cDNA sequence and whole plantshikimate accumulation assay were performed on L. corniculatus in order investigate tolerance mech-anisms. No amino acid substitution related to glyphosate tolerance was found on EPSP synthase cDNAsequence. The shikimate accumulation study indicates that limited uptake and/or translocation of theherbicide is the most probable tolerance mechanism. Results obtained in this study, plus the produc-tive and adaptive advantages of L. corniculatus make it a valuable candidate to develop rhizoremediationstrategies.