Mycorrhizal influence on metabolites, indigestible oligosaccharides, mineral nutrition and phytochemical constituents in onion (Allium cepa L.) plant

• Study on modified stem vis a vis mycorrhizal relationship of a modified stem than normal root.
• AM fungi in onion were found enhancing metabolites and mineral nutrition in onion bulb.
• It is the first report that AMF can increase the indigestible oligosaccharides in onion bulb.
• The AMF induces the phytochemical changes within the bulbs of onion plant.

Mycorrhizal fungi are symbionts forming mutualistic relationship with plant roots. In the present study, surface sterilized onion seeds were sown in earthen pots filled with sterile soil. Half the pots were inoculated with sterilized arbuscular mycorrhizal fungi (AMF) spores and sterilized inoculated maize root fragments and another half without any AMF inoculation represented control but were provided sterilized maize root fragments having no AMF colonization. After 40 days of germination, the inoculated plants along with their controls were sampled at 20, 40, 60 and 80 days of growth. The bulbs of onion plant are shown to present a higher level of metabolites like carbohydrates, protein and phenolics, and mineral nutrition in the mycorrhizal ones as compared to the non-inoculated ones. The HPLC analysis depicted that indigestible oligosaccharides are increased due to AMF inoculation. Phytochemical changes in the AMF infected plants in comparison to their respective controls by GC–MS analysis are also reported here in.