Endophytic bacteria associated with banana cultivars and their inoculation effect on plant growth

The occurrence and role of endophytic bacterial communities in banana under different field-grown conditions have not yet been explored. Hence, a survey was conducted in five different banana cultivars - Rasthali, Hill banana, Co1, Nattu Poovan and Red banana - for the assessment of bacterial endophytes grown in Tamil Nadu, Southern India. From 352 endophytes isolated, 17 were selected based on distinct morpho-physiological characters. The 17 selected isolates were grouped into eight different genera, which belong to the phyla Actinobacteria, Firmicutes and Proteobacteria, with remarkable differences in the bacterial compositions among the banana cultivars. Higher bacterial diversity was observed in Rasthali and Red banana when compared to Co1 and Nattu Poovan. Isolates exhibited at least one functional plant growth-promoting trait when tested for siderophore production and indole-3-acetic acid (IAA) synthesis. Representative isolates from eight different genera were further analyzed for plant-microbe interactions. A seedling inoculation experiment on tomato showed a significant effect on seed germination, seedling growth, vigor index, and biomass production compared to the uninoculated control. However, a comprehensive approach is needed to evaluate the full potential of bacterial endophytes to improve quality and yield in banana under field conditions.