Exploring the Suillus luteus genome to understand the functional ecology of an ectomycorrhizal fungus adapted to heavy metal stress (R-4205)

Suillus luteus is an ectomycorrhizal symbiotic fungus that colonises the fine absorption roots of pine trees. From the mycorrhizal root tips, an extensive network of fungal hyphae extends into the surrounding soil, scavenging for nutrients. A significant part of these nutrients is provided to the host plant in exchange for carbohydrates. This particular fungal species has evolved metal-tolerant populations on severely metal-contaminated sites. This adaptive metal tolerance, which is based on metal exclusion, is of great importance for the host tree. The fungus not only avoids an excessive transfer of the toxic metal(s) towards the plant but in the same time improves the transfer of essential nutrients, which are often very scarce in these metal-contaminated soils. How these adaptive ecotypes realise metal tolerance and meanwhile maintain a balanced nutrient uptake under these harsh conditions remains unknown. The aim of this project is to decipher these mechanisms making use of the forthcoming genome sequence of a zinc-tolerant S. luteus. Gene repertoires involved in heavy metal homeostasis and tolerance and in micro- and macronutrient mobilization will be identified and compared with other mycorrhizal fungi that are currently sequenced. Genes of interest will be functionally characterised through complementation studies in yeast and expression of these key genes will be investigated in different S. luteus ecotypes.

Keywords:HEAVY METALS, SOIL CONTAMINATION

Disciplines:General biology, Plant biology