|Gonzalez-chavez, Ma. Del Carmen|
Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2004
Publication Date: 5/1/2004
Citation: Gonzalez-Chavez, M., Carillo-Gonzalez, R., Wright, S.E., Nichols, K.A. 2004. The role of glomalin, a protein produced by arbuscular mycorrhizal fungi, in sequestering potentially toxic elements. Environmental Pollution. 130:317-323. Interpretive Summary: Mechanisms to remediate soils that are polluted with heavy metals are needed worldwide. Wind and water erosion can carry pollutants into water and adjoining areas, unless polluted mine soils and soils polluted by other means are stabilized by plants. Naturally-occurring organic compounds in soils sequester potentially toxic elements (PTEs). Three experiments were performed to test whether PTEs are bound to an organic compound, glomalin, copiously produced and deposited in soil by common fungi that colonize plant roots. These experiments addressed binding of PTEs in polluted soils and binding of copper under controlled conditions by glomalin. Results from all of the experiments indicated that glomalin binds large amounts of PTEs. Growth of the fungi that produce glomalin can be optimized, even on polluted soils where growth of some plants is inhibited, by selecting appropriate plants and inoculating the plants with compatible and effective fungi. Therefore, glomalin should be considered for biostabilization leading to remediation of polluted soils.
Technical Abstract: Naturally-occurring soil organic compounds stabilize potentially toxic elements (PTEs). This study investigated sequestration of PTEs by the glycoprotein, glomalin, produced by arbuscular mycorrhizal fungi (AMF) in three experiments. Glomalin from two polluted soils had 1.6 - 4.3 mg Cu, 0.02 - 0.08 mg Cd and 0.62 - 1.12 mg Pb/g glomalin. Glomalin from hyphae of an isolate of Gigaspora rosea sequestered up to 28 mg Cu/g in vitro. Cu-tolerant and non-tolerant isolates of Glomus mosseae colonizing sorghum in an in vivo experiment were fed with nutrient solution containing 0.5, 10 and 20 M of Cu. Although no differences between isolates were detected, mean values for the 20 M Cu level were 1.6, 0.4, and 0.3 mg Cu/g for glomalin from hyphae, sand after removal of hyphae and roots, respectively. The Cu-glomalin complex is probably a combination of weak association and strong, irreversible sequestration. Glomalin should be considered for biostabilization leading to remediation of polluted soils.