Etude de l’aptitude des souches fongiques, isolées de la rhizosphère de deux plantes steppiques de la région minière d’Ain-Babouche, à la remédiation des sols métallifères.

Abstract

The aim of this work is to highlight a resistant endophytic mycoflora in the roots of two metallophylic species Hedysarum pallidum Desf. and Lygeum spartum L. growing on soil contaminated with antimony (Sb) and arsenic (As) in Djebel Hamimat (Algeria) region, to study the toxicity of mycoendophytes with respect to toxicity of Sb and As, to evaluate the level of oxidative stress and the antioxidant defense systems of Aspergillus tubingensis and Fusarium oxyporum induced by metalloid toxicity. Our work demonstrates, the presence of mycoendophytes associated with the roots of the two plant species studied for the first time in Algeria; H. pallidum, and L. spartum. This latter have a colonization frequencies of 64.58% and 96.87% respectively. among the isolated mycoendophytes, only Aspergillus tubingensis was resistant to 500 mM Sb, and Fusarium oxysporum tolerated 30 mM As. The toxicity tests in vitro on A. tubingensis and F. oxysporum revealed that these strains accumulated a significant amounts of Sb in their biomass, in contrast to As. As regards the indicators of the oxidative stress level and the antioxidant responses of the two endophytic species, MDA, H2O2 and intracellular proline content increase significantly with increasing doses of Sb and As in the culture medium. Antioxidant responses vary quantitatively and qualitatively from a fungal species to another, and from a metalloid to another. This suggests that these endophytic strains may be potential agents for the bioremediation of soil and aquatic environments contaminated with antimony and arsenic.