Study on the seasonal endobacterial profile of Avicennia officinalis, focusing on core bacterial consortia within mangrove pneumatophores

Microhabitats are smaller pockets of ecosystems with unique conditions and they serve as major contributors of species richness. Mangrove plants offer a diverse array of such microhabitats (rhizosphere, phyllosphere, endosphereetc), and the inhabitant bacteria benefit the host by providing better salinity tolerance, faster and better nutrient mobilization, protection from phytopathogens and assistance in seed germination. Identification of such beneficial bacteria,their growth requirementsandmetabolism, willhave direct application in the field of agriculture and ecosystem restoration. Hence in this study, effort has been made to elucidate the seasonal numerical and compositional profile of pneumatophore bacterial consortia of Avicennia officinalis, from the mangrove ecosystemof Poovar, South Kerala, India. The physico-chemical parameters of mangrove water, micronutrient availability within the pneumatophore and the count,morphologyand biochemical characteristics of the endosymbiont bacterial consortia were analyzed simultaneously. Significant variation is observed across the rainy and the non-rainyseasons, in the water parameters and in the endobacterial CFU count. Antagonistically,the micronutrient contentand the endobacterial composition of the pneumatophore remained stable across the seasons. The biochemicalprofile of the endobacterial consortia illustrated the metabolic co-dependence and complementarity among the host and the symbiotic consortia,which substantiate the need for such a solid core bacterial consortium within the plant host. Further studies are warranted in this lane to trace the beneficial metabolic pathways of symbiotic bacterial strains, which could find wide application in the field of agriculture and human health.