A new system using Solanum tuberosum for the co-cultivation of Glomus intraradices and its potential for mass producing spores of arbuscular mycorrhizal fungi

Freshly harvested potato tubers, Solanum tuberosum var 'Pukhraj', were inoculated for transformation with Agrobacterium rhizogenes strain Ri1600. Hairy roots were formed after 8 days of co-cultivation and the transformation efficiency was 40 %. The transformants were transferred from Murashige and Skoog medium (MS) to Modified White's medium (MW) and finally on a hormone-free minimal medium (M). The putative transformants were confirmed using rolA and rolB gene specific primers for the polymerase chain reaction (PCR) analysis. The root inducing (Ri) T-DNA transformed potato roots were co-cultured with Glomus intraradices (CMCCROC7) to obtain arbuscular mycorrhizal root organ cultures (AM-ROC dual cultures), which were used for studying the symbiosis with Glomus intraradices and the potential for spore production in vitro. Sporulation was comparable with the existing in vitro carrot-dual culture system. Around 60,250 spores/jar could be harvested with around 38,314 extraradical spores/jar and around 21,936 intraradical spores/jar. The new method using potato is certainly promising for the mass production of mycorrhizal biofertilizers. The viability of the spores when tested on potato roots was nearly 100 % and more than half of the roots were colonized 12 weeks after inoculation.