Colonization and antagonistic activity of endophytic fungi in seagrasses: Understanding endophyte interactions

ABSTRACT

Aims@#This study assessed the colonization and antagonistic interaction of endophytic fungi isolated from the Philippine seagrasses. @*Methodology and results@#A total of 2690 explants from Enhalus acoroides, Thalassia hemprichii and Cymodocea serrulata were examined in this study. The colonization rate per seagrass species and tissue type were calculated from the number of explants with fungal growth after 14-day incubation on PDA culture media. The presence of fungal structures in seagrass tissues was examined by a histological method. The co-culture method and non-volatile compound assays determined the interaction between endophytic fungal species. Results showed that eight species of endophytic fungi colonized seagrasses, varying with host species and tissue types. Aspergillus ochraceopetaliformis and Penicillium citrinum were the most predominant particularly in E. acoroides leaves. Histological examination of seagrass explants revealed that endophytic fungi preferably colonize the intercellular and intracellular spaces of the cortical tissues. No fungal hyphae were detected in the vascular tissues of the three seagrass species suggesting no systemic fungal growth. The endophytic fungi in seagrasses interact antagonistically with each other in which hyphal interference, the presence of a demarcation line at the interaction zone, changes in colony colour and growth inhibition were observed during the interaction.@*Conclusion, significance and impact of study@#Seagrasses were colonized by a dynamic assemblage of endophytic fungi, which interact antagonistically with each other. Endophytes’ ability to restrict the growth of other fungal species during interaction suggested their importance in biocontrol and the production of inhibitory molecules.