Abstract:
Aims: Endophytic fungi are a diverse group of microorganisms that stay asymptomatically in the healthy tissues of the
host. Many fungal endophytes are associated with the tea plant (Camellia sinensis) and the pathogens of the tea plant
have the potential to grow as endophytes or act as latent pathogens during the initial growth of the plant. The present
study aimed at screening tea endophytic fungi with the potential for control of a few critical phytopathogens, Fusarium
sp., Lasiodiplodia theobromae, Pestalotiopsis sp. and Sclerotinia sclerotiorum while evaluating the efficiency of growth
inhibition of these phytopathogens by the endophytic fungal isolates using in vitro assays.
Methodology and results: Five endophytic fungal strains; Colletotrichum gloeosporioides, C. siamense, Daldinia
eschscholtzii, Pseudopestalotiopsis chinensis and Phyllosticta capitalensis isolated from leaves of C. sinensis in Sri
Lanka were evaluated for growth inhibition against plant pathogens; Fusarium sp., L. theobromae, Pestalotiopsis sp. and
S. sclerotiorum using the dual culture assay and volatile compound-mediated inhibition assay. All the fungal endophytes
used in this study exhibited antifungal activity against Fusarium sp., Pestalotiopsis sp. and S. sclerotiorum in the dual
culture assay on PDA. Daldinia eschscholtzii (67.30%) and C. gloeosporioides (61.54%) showed strong antagonistic
activity against S. sclerotiorum, while P. capitalensis (42.30%) demonstrated moderate activity. All the endophytic fungal
strains showed moderate antifungal activities against Fusarium sp. The percentage growth inhibitions of Pestalotiopsis
sp. by all the endophytic isolates tested were below 25.00%. In the volatile compound-mediated inhibition assay, none of
the endophytic isolates showed visible inhibition against the phytopathogens used.
Conclusion, significance and impact of study: In this study, the fungal endophytes which showed potential
antagonistic activity against the tested phytopathogens can be used to develop commercialized products of fungal
biocontrol agents (BCAs) for controlling plant fungal diseases.
