Spore liberation and dispersal in smut fungi

Teliospores are the most important diaspores of smut fungi, albeit not the only ones. The role of basidia, basidiospores, secondary spores, yeast cell s, and infected parts of the host for dispersal has often been neglected. M any smut species have soral structures like galls, peridia, and elaters, wh ich cause teliospores to be liberated over prolonged periods. This increase s the chance that at least some spores are released under favourable wet cl imatic conditions and while host plants are susceptible. In this review, the diversity of dispersal units as well as vectors of smut fungi are presented. The importance of timing of diaspore liberation, flex ibility in dispersal strategies, and the genetic and evolutionary implicati ons of dispersal strategies of smut fungi are discussed. The general considerations are complemented by examples based on original f ield and laboratory observations: peridia of Forysia corniculata and certai n species of Sporisorium expose the spore mass by hygroscopic movement unde r wet conditions (hygrochasy) favourable for teliospore germination and inf ection of a host plant. Basidia with firmly attached basidiospores liberate d from spore balls of Doassansiopsis deformans, branched basidiospores of R homphospora nymphaeae, needle-shaped basidiospores of species of Entyloma, folded basidiospores of Mycosyrinx cissi, and stellate groups of yeast cell s of Trichocintractia utriculicola show enlarged surfaces, which are advant ageous for dispersal in water. Galls Filled with spore balls of Doassansiop sis limnocharidis and witches' brooms formed by spikelets infected by Cintr actia standleyana separate from the host and fall into water where they are dispersed.