Diversity and Antimicrobial Activity of Endophytic Fungi Associated with Houttuynia cordata Thunb

The study focused on the endophytic fungi associated with Houttuynia cordata Thunb., also known as Fish mint, from four districts of Assam, India. This plant is widely used in traditional medicine to treat various ailments such as dysentery, cold, fever, mumps, etc. The investigation aimed to isolate and identify these fungi from healthy plant tissues and to assess their antimicrobial properties. Sixty-one endophytic fungal isolates were obtained from the leaf, stem, and root tissues of H. cordata. The highest fungal population was recorded in samples from North Lakhimpur district, followed by Nagaon and Kamrup (M) districts. Among the isolated fungi, one particular strain of Trichoderma obtained from Nagaon district showed significant antifungal activity against six test fungal pathogens in vitro. The fungal species was further identified as Trichoderma virens strain MBDM1 through 28S rDNA sequence analysis and molecular phylogeny. The ethyl acetate extract of T. virens was analyzed using GC-MS, revealing the presence of six fungicidal metabolites: 1-H-benzotriazol, Trans,cis-1,7-dimethylspiro[4.5]decane, 2H-Pyrane-2-one-tetrahydro-6-pentyl 4-nitro-, 8-decanoic acid, Thiazolo[3,2-a]benzimidazol-3(2H)- one and Cyclotrisiloxane hexamethyl. These compounds are likely responsible for the antifungal activity against the test fungal pathogens.. KEYWORDS :Antifungal activity, Antimicrobial metabolites, Endophytic fungi, Houttuynia cordata, Trichoderma