Cell wall proteins of the ectomycorrhizal basidiomycete Pisolithus tinctorius: Identification, function, and expression in symbiosis

Specific cell-cell and cell-substrate interactions direct the growth of ect omycorrhizal fungi to their host root targets. These elaborate mechanisms l ead to the differentiation of distinct multihyphal structures, the mantle, and the Hartig net. In the ectomycorrhizal basidiomycete Pisolithus tinctor ius, the use of two-dimensional gel electrophoresis, immunocytochemical mic roscopy, and RNA blot analysis has demonstrated the differential expression of cell wall proteins (CWPs), such as hydrophobins, adhesins, and mannopro teins, during symbiotic interaction. In other fungi, these CWPs have been s uggested to play a role in hyphae aggregation, intracellular signaling casc ades, and cytoskeletal changes. The recent cloning of the genes for several of these CWPs in P. tinctorius allows us to address their function in symb iosis. This review summarizes our knowledge of CWPs in P. tinctorius and co nsiders parallels with other biotrophic fungi as a possible framework for f uture work. (C) 1999 Academic Press.