Histological localization of fungal endophytes in healthy tissues of Adhatoda vasica Nees

A research protocol has been developed to locate endophytic fungi present inside the healthy leaves and stems of Adhatoda vasica using the microtome technique. The surface-sterilized explants after staining with lactophenol cotton blue showed the presence of endophytic fungi in intercellular spaces of ground and dermal tissues. In transverse sections of leaf at 100x magnification, dense blue colonies of endophytic fungi in epidermis and mesophyll region were recorded, while sprinkled colonies were seen in vascular bundles. In transverse sections of stem at 100x magnification, dense colonies of endophytic fungi in phloem and slightly lesser in epidermal region were observed. Scattered colonies were also recorded in xylem and cortex tissues. The fungal colonies were also present in intracellular and extracellular regions of both explants. Further studies will be required to identify these fungal isolates through pure culture on PDA plates to explore their biosynthetic pathway.