Why Sequence White Rot Fungus?

White rot fungi produce unique extracellular oxidative enzymes that degrade lignin, as well as related compounds found in explosive-contaminated materials, pesticides, and toxic wastes.

Lignin plays a key role in the carbon cycle as the most abundant aromatic compound in nature, providing the protective matrix surrounding the cellulose microfibrils of plant cell walls. Although lignin is a formidable substrate, its degradation by certain fungi was recognized and described nearly 125 years ago. The organisms responsible, collectively referred to as white rot fungi (since they degrade brown lignin and leave behind white cellulose), are basidiomycetes, a fungal group that includes edible mushrooms as well as plant pathogens such as smuts and rust. Phanerochaete chrysosporium is the first basidiomycete genome to be sequenced.

Phanerochaete chrysosporium has been the most intensively studied white rot fungus. White rot fungi secrete an array of peroxidases and oxidases that act nonspecifically via the generation of lignin free radicals, which then undergo spontaneous cleavage reactions. The nonspecific nature and exceptional oxidation potential of the enzymes has attracted considerable interest for application in bioprocesses such as organopollutant degradation and fiber bleaching.

Phanerochaete chrysosporium has several features that might make it very useful. First, unlike some white rot fungi, it leaves the cellulose of the wood virtually untouched. Second, it has a very high optimum temperature (about 40 degrees C), which means it can grow on wood chips in compost piles, which attain a very high temperature. These characteristics point to some possible roles in biotechnology.

Genome Portal site: Phanerochaete chrysosporium