Hemasri N.K., Arun Nagendran N. and Saraswathi K.
Abstract
Endophytic fungi colonizing the inner parts of plants provide both direct and indirect benefits to their hosts. These fungi also assist in the invasiveness of exotic species by producing growth-promoting substances. Hence, in the present investigation, endophytes associated with the leaves and stems of an exotic, invasive species, Senna spectabilis, were isolated based on the hypothesis that the associated endosymbiotic fungi produce a notable quantity of growth-promoting substances. Their growth-promoting efficacy was evaluated. Three fungal endophytes, namely Aspergillus niger, Aspergillus flavus and Schizophyllum commune were isolated from S. spectabilis and identified using ITS sequencing. All three isolates exhibited extracellular enzymatic activities, phosphate solubilization ability and production of the phytohormone indole-3-acetic acid. Enzymes, which are hydrolytic in nature, such as amylase, cellulase, protease and pectinase were produced at higher levels by A. niger. S. commune, in the presence of tryptophan, exhibited the highest lipase activity, the greatest phosphate-solubilizing index and the highest indole-3-acetic acid synthesis. All three isolates enhanced seed germination and seedling vigour in Vigna radiata, especially when applied as a consortium. The present study indicates that these endophytes can be effectively exploited as bioinoculants both individually and in consortium for sustainable agricultural production.