Assessment of diversity, distribution and antibacterial activity of endophytic fungi isolated from a medicinal plant Adenocalymma alliaceum Miers Ravindra N. Kharwar & Satish K. Verma & Ashish Mishra & Surendra K. Gond & Vijay K. Sharma & Talat Afreen & Anuj Kumar Received: 7 July 2011 /Accepted: 19 November 2011 /Published online: 6 December 2011 # Springer Science+Business Media B.V. 2011 Abstract A study was conducted for isolation, identifica- tion and antibacterial potential of fungal endophytes of Adenocalymma alliaceum Miers., (Bignoniaceae), a medic- inal shrub vine plant which has long history for its usages in curing various disorders. A total of 149 isolates of endo- phytic fungi representing 17 fungal taxa were obtained from 270 segments (90 from each stem, leaf and petiole) of this plant. Hyphomycetes (77.85%) were the most prevalent, followed by Ascomycetes (8.05%) and Coelomycetes (4.03%) respectively. A considerable amount of fungal iso- lates was kept under (10.07%) Mycelia-Sterilia (MS). Leaf harboured maximum colonization of endophytic fungi (72.22%) which was greater than stem (67.78%) and petiole (25.54%). The Jc similarity index was maximum (0.619) between stem vs leaf followed by leaf vs petiole (0.571) and stem vs petiole (0.428). The dominant endophytic fungi were Alternaria alternata, Aspergillus niger, Stenella agalis, Fusarium oxysporum, Curvularia lunata and Fusarium roseum. Among twelve endophytic fungi tested for antibac- terial activity, crude extracts of nine endophytic fungi (75%), showed antibacterial potential against one or more clinical human pathogens. Alternaria alternata, Curvularia lunata, Penicillium sp. and Chaetomium globosum exhibited significant antibacterial activity against 4 of 5 tested pathogens, showing broad spectrum activity. This in- vestigation explains the value of sampling from different tissues of a host plant for the greater species diversity, and additionally, the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for many of the useful antibacterial compounds. Keywords Antibacterial . Adenocalymma alliaceum . Colonization frequency . Diversity . Endophytic fungi 1 Introduction Endophytes are all those microorganisms that colonise and cause asymptomatic infections in healthy plant tissues (Wilson 1995), and provide an effective protection to the concerned hosts against array of biotic and abiotic stresses (Omacini et al. 2001 and Redman et al. 2002). Endophytes in general, are very important and viable components of microbial biodiversity. Fungal endophytes are ubiquitous among terrestrial plants (Petrini et al. 1982 and Carroll 1988), having been reported in algae (Hawksworth 1987), lichen (Petrini et al. 1990 and Li et al. 2007), mosses (Schulz et al. 1993), conifers (Carroll and Carroll 1978), and angiosperm (Clay 1988; Rodrigues 1994; Hyde et al. 1997; Verma et al. 2007 and Gond et al. 2007). The fungi are considered hyperdiverse, as 1.5 million of species have been estimated (Hawksworth 2001) and only 6–7% of this has been described so far while, rests are still awaiting their chance to be introduced to existing microbial world. Temperate plants are maximally studied for endo- phytic fungi, thus the fungal endophytes of the tropical plants need to be explored to describe for the remaining 93% of mycoflora (Murali et al. 2007). R. N. Kharwar (*) : S. K. Verma : A. Mishra : S. K. Gond : V. K. Sharma : T. Afreen Mycopathology and Microbial Technology Laboratory, Department of Botany, Banaras Hindu University, Varanasi 221005, India e-mail: rnkharwar@yahoo.com A. Kumar Department of Botany, Buddha P. G. College, Kushinagar, UP, India Symbiosis (2011) 55:39–46 DOI 10.1007/s13199-011-0142-2