Unresolved Problems in the Life Cycle of Truffles

ABSTRACT

The mating system and ploidy level of truffles, both mycorrhizal and sterile fruit-body hyphae are the subject of conflicting hypotheses. The current dogma concerning Ascomycetes, supported by recent studies on truffles, maintains that the mycorrhizing mycelium is homokaryotic and that the short-lived ascogenous heterokaryotic hyphae resulting from the fertilization process occur only in truffle primordia. Therefore the gleba and sterile veins are also homokaryotic. Other studies show heterokaryons both in gleba and mantle hyphae of some truffle species, leading to the conclusion that longterm heterokaryons do exist in truffles. The matter is discussed.