Fungal and Plant Diversity and Correspondence with Soil and Environmental Properties on Brownfields in a Semi-Arid Area

Certain fungi, including root-associated fungi, are capable of degrading organic contaminants of concern and enhancing the bio and phyto-remediation of metal and mixed contaminated soils. A better understanding of the fungal diversity of contaminated sites in arid and semi-arid regions can aid in selection of top fungal candidates for application in remediation, and understanding which variables control fungal diversity and abundance on contaminated sites sets the stage for unraveling the mechanisms requiring understanding for their successful application in field settings. Eight contaminated sites (known as brownfields) across semi-arid Southern California were surveyed for plant and microbial volunteers with the goal of identifying locally adapted species tolerant of the mixed organic and inorganic contaminated soils and the hot and dry climate found regionally. Several native hyperaccumulators of metals of concern were identified after sampling using microwave digestion and ICP-MS. Soil physico-chemical properties, environmental variables such as soil moisture, and microbial diversity were analyzed and the 16S, SSU and ITS2 regions of DNA extracted from interspace and rhizosphere soils were sequenced to identify bacterial and fungal, including mycorrhizal, diversity and abundance. Fungi from the Ascomycota including known petroleum-degrading fungi were dominant across all sites. A CCA was run to analyze the correspondence between soil physical and chemical properties including contaminant type and concentration, environmental variables, and fungal diversity was undertaken. The results presented aim to elucidate which soil and environmental variables are correlated with the fungal diversity on contaminated sites and help unravel the interactions between mycorrhizas, other fungi, and plants in these contaminated environments.