Natural existing arbuscular mycorrhizal-bacterial biofilm associations and their functional behavior
Aditi Pandit1,2,3, Leena Johny1, David Cahill2, Lambert Brau2, Alok Adholeya1 and Mandira Kochar1
1TERI Deakin Nanobiotechnology Centre, Sustainable Agriculture Division, The Energy and Resources Institute, TERI Gram, Gwal Pahari, Gurugram, Haryana 122103, India
2School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Geelong, Victoria 3216, Australia
3University of South Bohemia, Department of Ecosystem Biology, České Budějovice 37005, Czech Republic
In symbiosis with plants, arbuscular mycorrhizal fungi (AMF) access the stored carbon from the roots in exchange for nutrients and water uptake. In the mycorrhizal-plant symbiosis, AMF–associated bacteria (AAB) serve as a third partner and are tightly associated with AMF. AABs are involved in mycorrhizal activity and nutrient uptake enhancement and have an impact on plant development. In order to create biofertilizers for sustainable crop production, it is important to understand the function and process of this cross-kingdom natural coexistence. In our research, we used 33 isolates of in-vitro and in-situ grown AMF co-cultures, and characterized 231 AABs using 16S rDNA analysis. 109 selected AABs were examined for ten functional qualities that promote plant growth, and it was found that different bacterial strains had a variety of advantageous traits. The association of AABs was seen as biofilm and endobacteria using microscopic methods. Further, by using an optimized in-vitro plate assay system, an association recreation of 11 AAB-Rhizophagus irregularis was investigated to look at the impact on mycorrhization and different functional capabilities. It was observed that AABs moved along the developing R. irregularis hyphae and spores. Different AABs had an impact on AMF sporulation as well as their capability to solubilize phosphate and potassium and nitrogen fixation. We discovered both the synergistic interactions and partnerships between the two inter-kingdom microbial partners. Understanding the molecular elements of these fungal-bacterial connections, which will enable their later use and modification for sustainable agriculture practices, is another area of focus.