Short-term chromium (VI) exposure increases phosphorus uptake by the extraradical mycelium of the arbuscular mycorrhizal fungus Rhizophagus irregularis MUCL 41833

GIL CARDEZA ML, CALONNE-SALMON M, GÓMEZ E, DECLERCK S

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2017

0045-6535

Hexavalent chromium is a potent carcinogen, whilephosphorus is an essential nutrient. The role of arbuscular mycorrhizal fungi  (AMF)  in the uptake of P is well known and was alsoreported, at low levels, for Cr. However, it is unclear whether the uptake ofCr can impact the short­-term uptake dynamics of P since both elements have a similarchemical structure  and may thuspotentially compete with each other during the uptake process. This studyinvestigated the impact of Cr(VI) on short-term P uptake by the AMF Rhizophagus irregularis  MUCL 41833 in Medicago truncatula. Bi-compartmented Petri plates were used tospatially separate a root compartment (RC) from a hyphal compartment (HC) usinga whole plant in vitro culture system.The HC was supplemented with Cr(VI). Chromium(VI) as well as total Cr and P weremonitored during 16 h within the HC and their concentrations determined by theend of the experiment within roots and shoots. Our results indicated that the uptake and translocationof Cr from hyphae to roots was a fast process: roots in which the extraradicalmycelium (ERM) was exposed to Cr(VI) accumulated more Cr than roots of which theERM was not exposed to Cr(VI) or was dead. Our results further confirmed that deadERM immobilized more Cr than alive ERM. Finally our results demonstrated that theshort exposure to Cr(VI) was sufficient to stimulate P uptake by the ERM andthat the stimulation process began within the first 4 h of exposure.