Macroconida and microconida spores of Nectria haematococca MPVI. Photo by Dr. Dai Tsuchiya

The fungus Nectria haematococca Mating Population VI (MPVI), also commonly referred to by its asexual name Fusarium solani is a member of an evolutionary group called the Fusarium solani species complex, which is comprised of about 50 species. The term "mating population" refers to the fact that members of MPVI are sexually fertile with one another, indicating that they form a biological species.

Members of the F. solani species complex have an ubiquitous distribution and colonize a wide variety of habitats. They can be found as soil-inhabiting saprophytes, rhizosphere colonizers, or as pathogens, which cause disease on many plant and animal species, including humans.   Perhaps because of their cosmopolitan nature these fungi have an impressive range of metabolic capabilities; they can degrade a variety of recalcitrant compounds such as lignin and lignocellulose, hydrocarbons (e.g., pyrene, fluoroacetate), plastics, pesticides (e.g., DDT, butachlor, ioxynil), and cyanide complexes. Indeed, N. haematococca MPVI is tolerant to many compounds shown to be toxic to other fungi, including antibiotics, heavy metals and metabolic poisons.

N. haematococca MPVI is the most studied of the F. solani complex and some of the genes controlling the ability of this fungus to colonize specific habitats are located on conditionally dispensable supernumerary chromosomes ("CD chromosomes"), which were first described in this fungus in 1991. These chromosomes are known to carry habitat-defining genes involved in resistance to plant antibiotics, the utilization of specific carbon and nitrogen sources, and in host-specific pathogenicity. The most relevant aspect of the biology of the CD chromosomes is the evidence suggesting that they originated by horizontal gene transfer. The availability of the genomic sequence of N. haematococca MPVI will allow a critical test of this hypothesis. In addition, the genomic sequence should assist the identification of genes from specific biosynthetic and catabolic processes involved in the responses of this fungus to a variety of environmental conditions (e. g. toxic chemicals, stress, recalcitrant carbon sources, pathogenic vs. saprophytic growth, anaerobic growth, etc.). Thus, the genomic sequence of this fungus should be of great interest to a number of user communities, including those engaged in bioremediation, biotechnology, agriculture, evolutionary studies, comparative genomics, and computational biology.