In vitro mass-production of the arbuscular mycorrhizal fungus, Glomus versiforme, associated with Ri T-DNA transformed carrot roots

Abstract

The rate of in vitro spore formation of the arbuscular mycorrhizal fungus Glomus versiforme was followed in Petri dishes, using mycorrhizal root-segment inoculum associated with Ri T-DNA transformed carrot roots. Three phases of sporulation were observed: a lag phase, a period of intensive spore production and a plateau phase. An average of 9500 spores per Petri dish was produced after 5 months of dual culture. The root-organ culture system supported extensive root colonization, with many arbuscules and vesicles being formed. The fungus, both within root-segments and as spores produced, was viable and able to complete its life cycle in vitro. The mycorrhizal root-segments, however, exhibited higher inoculum potential due to the numerous vesicles and extensive intraradical mycelium.