Cultivation of Edible Ectomycorrhizal Fungi by in Vitro Mycorrhizal Synthesis

Abstract

A significant proportion of ectomycorrhizal fungal species form edible fruiting bodies, and several of these species are important commercially. The most highly regarded ectomycorrhizal fungi include truffles, in particular, the Italian white truffle (Tuber magnatum Pico) and Perigord black truffle (Tuber melanosporum Vittad.), chanterelle (Cantharellus cibarius Fr.), porcini (Boletus edulisBull.: Fr. sensu latu), andmatsutake [Tricholoma matsutake (S. Ito et Imai) Sing.]. Though generally not as highly regarded, species such as the saffronmilk cap [Lactarius deliciosus (L.: Fr.) S.F. Gray], Caesar’s mushroom [Amanita caesarea (Scop.:Fr.) Pers.], burgundy truffle (Tuber uncinatum Chatin), bianchetto truffle (Tuber borchii Vittad.) and shoro [Rhizopogon rubescens (Tul.) Tul.] are also popular in some countries. Very high prices are paid for the truffles. For example, in 2003, a year in which harvest was poor, the prized Italian white truffle (T.magnatum) sold for US$ 2,200–4,600/kg (http://www.tuber.it/pagine/comuni/borsa.php), while the Perigord black truffle retailed for US$ 900–2,000/kg and the bianchetto truffle, generally modestly priced, for US$ 300/kg (http://www. Acqualagna.info/). Matsutake is also very highly regarded, and grade 1 can retail forUS$ 1,250/kg ormore (Martinez-Carrera et al. 2002).Despite these high prices, over the past fewdecades, there has been a steady upward trend in the price paid for these fungi, due to a general decline in production (Hall et al. 2003a). Numerous factors have led to this steady decline in production, including deforestation, the introduction of exotic forest species that are not symbiotic with edible mycorrhizal mushrooms, poor forest management and indiscriminate harvesting of fruiting bodies. Other factors, such as