Actively growing extraradical hyphae extending from mycorrhizal plants are an important source of inoculum in soils which has seldom been considered in vitro to inoculate young plantlets. Seedlings of Medicago truncatula were grown in vitro in the extraradical mycelium network extending from mycorrhizal plants. After 3, 6, 9, 12, and 15 days of contact with the mycelium, half of the seedlings were harvested and analyzed for root colonization. The other half was carefully transplanted in vitro on a suitable growth medium and mycelium growth and spore production were evaluated for 4 weeks. Seedlings were readily colonized after 3 days of contact with the mycelium. Starting from 6 days of contact, the newly colonized seedlings were able to reproduce the fungal life cycle, with the production of thousands of spores within 4 weeks. The fast mycorrhization process developed here opens the door to a broad range of in vitro studies for which either homogenous highly colonized seedlings or mass-produced in vitro inoculum is necessary.

Glomus cubense (Glomeraceae, Glomeromycetes) was isolated from a lagoon vegetation area on a clay soil deposition environment in the vicinity of San José de las Lajas, Cuba. The species description is based on spore morphological parameters from in vivo pot cultures and molecular analyses. The new species is characterized by its small, generally irregular in shape, 20-48 × (24–)54-72 μm hyaline to faintly yellow spores that have a 2-layered spore wall and arise in clusters. Phylogenetic analyses of the rDNA ITS region and H+ATPase place the species into the Glomeraceae without close relatives among named Glomus species. Glomus cubense forms mycorrhizal associations with sorghum and leek plants under greenhouse pot-culture growing conditions and with a diversity of crop plants under field conditions. The name cubense refers to Cuba, the country where the species was found.

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