Diversity and seasonal variation of fungal endophytes associated with Ageratum conyzoides L.: an invasive species

Fungal endophytes are important yet an underexplored group of microbial organisms that colonize healthy living plant tissues without developing any visible symptoms of disease. These microbes engage in a crucial role in the successful population establishment of alien invasive species in introduced ranges by altering native community structures. Thus, the present work was aimed to isolate and document the endophytic fungi associated with Ageratum conyzoides, an invasive plant species of Tripura, North-east, India, by selecting different vegetative parts viz. leaf, stem and roots, taking into consideration tissue type, sampling sites and season. For the isolation of fungal endophytes, selected explants of vegetative parts of A. conyzoides were inoculated in the MEA (Malt Extract Agar) medium. During this study from eight sampling sites, a total of 480 segments were inoculated, altogether 283 isolates were identified using morphology, microscopic, and molecular characteristics. The maximum number of endophytes were recovered from the stem (101 isolates) and leaf (99 isolates) segments compared to the root (83 isolates) segments. Twenty-two (22) endophytic fungal strains were identified among which nineteen (19) genera belonged to Ascomycota, one (1) in Mucoromycota, and the rest were sterile forms. The sampling site, tissue type, and season-wise diversity of endophytic fungi were analyzed. Pleosporales, Xylariales, and Eurotiales were represented by contributing the most species of endophytic assemblages. Results revealed that fungal endophytes isolated from invasive plant species exhibited tissue and seasonal specificity. This investigation is the first attempt on the study of diversity, tissue-specificity, and seasonal variation of endophytic fungi from invasive alien plant species Ageratum conyzoides of Tripura, Northeastern India (NEI).