Diversity of fungal endophytes from Phlogacanthus thyrsiformis (Roxb. Ex Hardw.) mabb., a promising medicinal plant in Arunachal Pradesh, northeast India

De Barry (1866) coined the term 'endophyte' to detect fungi which lives intercellularly and intracellularly in plants tissues, without causing any harm to the plant (Compant et al. 2017, Jeewon et al. 2017). Further, on the bases of their interaction with host plants, fungal endophytes may be divided into three groupscommensalists, parasites and mutualists (Jia et al 2016, Kirschner 2018). In mutualism, definite fungal endophytes gives tolerance to abiotic and biotic stresses on their host plants, improve their growth, and restrain diseases (Redman 2002, Rodriguez 2008). These Endophytes protect their hosts from infectious agents and adverse conditions by secreting bioactive secondary metabolites (Nath et al. 2012, Nongalleima et al. 2013). Endophytic fungi were reported in almost all the plants spp viz. algae, ferns, mosses and mainly in gymnosperms, angiosperms, reported from various parts of the world (Radic and Strukelj 2012, Doilom et al. 2017). Many researchers have proven that endophyte are the potential source of novel natural products for exploitation in modern medicine, agriculture and industry (Kaul et al. 2013). Till date it has been found that taxol can be produced by endophytic fungi Metarhizium anisopliae and Cladosporium cladosporioides (El-Maali et al 2018). Moreover, since, fungal endophytes can easily be grown in laboratories under routine culture techniques, hence, the potential for discovering virtually inexhaustible supply of metabolites is high. Fungal endophytes are capable of producing compounds similar to their host plants, and are capable in the preservation of world's diminishing biodiversity (Bender et al. 2016, Mane et al. 2017). However, the practicality of commercial production of compounds by The findings of the present study deals with the first type of its report, as presented in the current study, on the diversity of fungal endophyte from ethno medicinal plantPhlogacanthus thyrsiformis (Roxb.ex Hardw.) Mabb. , (Acanthaceae). The plant is growing wildly in the forest of Papum Pare, Arunachal Pradesh, India. The samples of the fungal endophytes were collected randomly from the study area and identified based on the morphological, cultural, and reproductive structures (hyaline, ellipsoidal, aseptate, pycnidia, beta conidia, perithecia, asci and ascospores). Further, the phylogenetic analysis of the isolated species was made, using the sequences of 5.8S and 28S rDNA internal transcribed spacer sequence 1 and 4. Overall, 41 fungal spp have been isolated, out of which 37 species belong to the class Ascomycetes; 01 species belong to the each class Zygomycota, Oomycota and Basidiomycota, respectively; however 01 fungal endophyte couldn't identified properly. The maximum number of fungal isolates were recorded from leaves (37%), followed by stems (33%) and root (30%). The observations shows that Colletotrichum siamense was the most dominant endophytic fungi, isolated from the selected plant (P. thyrsiformis); followed by Chaetomium globosum, Sordaria fimicola, Aureobasidium sp. , Pythiopsis cymosa etc. However, Colletotrichum siamense, Aspergillus fischeri, Plenodomus wasabiae, Aspergillus fumigatus, Nigrospora oryzae, Saccharomycetales sp. , Epicoccum nigrum. , Curvularia borreriae, Colletotrichum guajavae were the common fungal endophytes recorded from all the plant parts viz., leaf, stem and roots. Besides this, the density of colonization (rD%) was also recorded chronologically as Colletotrichum siamense (12.66%) < Chaetomium globosum (3.33%) < Sordariomycetes sp. , Sordaria fimicola and Aureobasidium sp. (2.66%) followed by the other remaining endophytes (0.66% to 2.00%), respectively.