MULTIPLE MECHANISMS OF ACTIONS AND ROLE IN ECTOMYCORRHIZAE SYMBIOSIS BY MYCORRHIZA HELPER BACTERIA: A MINI REVIEW

Abstract

Mycorrhiza helper bacteria (MHB) are organisms that specifically promote mycorrhiza formation especially
ectomycorrhizal fungi by producing growth metabolites that encourages easy proliferation of the fungal hyphae thereby
increasing the chances of the fungal hyphae to colonise plant roots with a large surface area. Mycorrhizal fungi are the
best-known examples of fungal and bacterial interactions as the hyphae offer good ecological niches for other microbes.
AM fungal spores harbour Bacteria Like Organisms (BLOs) also referred to as endosymbionts in their cytoplasm and
these organisms complete their life cycle within the eukaryotic cells giving rise to a further level of symbiosis. MHB may
play a vital role in root-fungus recognition, in fungal growth, in the modification of the rhizospheric soil. It may act as
stimulus to the formation of lateral roots in mycorrhizal plants as well as help in in germination of fungal propagules. The
specificity of the interaction between MHB and the fungi and between MHB and the symbiont plant have also been
explored.