|GONZALEZ-CHAVEZ, MA. DEL CARMEN|
|CARILLO GONZALEZ, RELOGIO|
Submitted to: Fourth International Conference on Mycorrhizae
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2003
Publication Date: 6/27/2003
Citation: Gongalez-Chavez, M., Carillo-Gonzalez, Wright, S.E., Nichols, K.A. 2004. Role of glomalin in sequestration of heavy metals. Fourth International Conference on Mycorrhizae. p. 503.
Technical Abstract: Bioremediation, specifically biostabilization, is a promising alternative for remediation of soils contaminated by potentially toxic elements (PTEs). This alternative involves the use of microorganisms and bioproducts to stabilize and ameliorate toxic effects of these elements to the plant-soil-environment system. There is evidence that arbuscular mycorrhizal fungi (AMF) may have an important role in polluted soils, such as an increment in plant tolerance and sequestration-accumulation of PTEs. It has been reported that arbuscular hyphae are involved in the sequestration and accumulation of PTEs at the cell wall level. However, the mechanisms used to withstand PTE are not very well understood. An exploratory study to investigate the possible participation of glomalin, a glycoprotein produced by all AMF, in sequestration of PTEs was performed. Glomalin was extracted from two polluted soils containing high concentrations of total and (DTPA)-available PTEs, by two autoclaving cycles using 50mM citric acid pH=8.0. Bradford total proteins (BTP), immunoreactive glomalin (IRG) and glomalin yield (GY) were determined from the extracts. The PTE content of glomalin was measured by atomic absorption spectroscopy. In Soil 1 (with higher available PTEs) lower BTP (0.49 mg protein g soil-1), IRG (0.18 mg protein g soil-1) and GY (2.35 mg glomalin g soil-1) were observed in comparison to Soil 2 which had 1.18, 0.67 and 6.4 mg g soil-1 of BTP, IRG and GY, respectively. Glomalin under natural conditions sequestered different PTEs from the soils. Sequestration by glomalin was higher in soil 2 (4.29 mg Cu, 1.12 mg Pb and 0.08 mg Cd g glomalin-1) than in soil 1 (1.55, 0.62, 0.02 mg g glomalin-1 for Cu, Pb and Cd, respectively), while Mn sequestration was similar in both soils. Glomalin sequestration and stabilization of these elements is interesting because of the toxicity of these PTEs to the soil-plant system.