Chapter 21 - Gene Transfer in the Fungal Host-Parasite System Absidia glauca-Parasitella parasitica Depends on Infection

Abstract

This chapter discusses the gene transfer in the fungal host—Parasite System Absidia glauca–Parasitella parasitica. Infection of the zygomycete Absidia glauca by the facultative mycoparasite Parasitella parasitica is accompanied by the formation of a limited cytoplasmic continuum between both partners. Successful infection of A. glauca by P. parasitica requires that the partners belong to complementary mating types. This observation points toward a physiological relationship between parasitism and the sexual pathway. In all mucoralean fungi, analyzed sexual differentiation depends on the synthesis of the sex pheromone trisporic acid. In A. glauca trisporic acid is synthesized via the complementary biosynthetic action of both mating types. Also complementary combinations between A. glauca and P. parasitica produce trisporic acid although this interspecific complementation does not induce the sexual pathway across genus borders. Therefore, it is hypothesized that trisporic acid is also involved in host–parasite recognition and presumably in mediating the first steps during the formation of infection structures. Mutants of A. glauca with defects in sexual spore formation were analyzed for their ability to serve as hosts for P. parasitica.