Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Screening and characterization of endophytes from selected medicinal plants and evaluation of their potential for bioactive natural compounds

Auteur : Sharma,Vijay Kumar

Université de soutenance : Banaras Hindu University

Grade : Doctor of Philosophy (PhD) 2016

Résumé partiel
Endophytic fungi are typically those that reside inside healthy parts of plants without causing detectable disease symptom to them. They are relatively less explored group of the fungal community, but recently they became of considerable interest to the scientific community due to their potential to produce novel and host origin natural compounds, and various other benefits like growth enhancement and herbivore resistance to the host plant. Practically, they can be any fungus/fungi that grow out from surface-sterilized healthy plant tissue on a provided culture medium. The present study assessed the diversity and potential of the fungal endophytes of Syzygium cumini L. The host plant is native to Indian subcontinent, commonly called as Jamun, has huge economic values and is attributed to posses several medicinal properties in the folk medicinal system of India. The plant samples (bark, leaf and stem) were collected from three different locations (Loc. 1 : BHU, Varanasi, U.P. ; Loc. 2 : Rethali, Meerut, U.P. ; Loc. 3 : Ranibagh, Nainital, Uttarakhand) in three different seasons (winter, summer and monsoon). The isolation of the endophytic fungi was performed after proper surface sterilization with NaOCl (4%), on PDA supplemented with 250 mg/l of streptomycin. A total of 2216 endophytic isolates belonging to 28 fungal taxa were recovered from 4050 tissue segments (1350 segments of each tissue) of Syzygium cumini. The isolated endophytic fungi were identified by their morphological and microscopic features, but mycelia sterilia were identified through molecular method and sequences have been deposited to the GeneBank database of NCBI with respective accession numbers. Out of 28 fungal species 21 were identified microscopically while 7 were identified using molecular method. Among tissues leaf harboured maximum endophytic diversity (number and type of fungal taxa) in all season at all location while bark was least colonized by endophytic fungi. Findings of this study suggest that among tissues, leaf harboured the maximum endophytic diversity (number of isolates and number of fungal taxa) in all seasons at all locations while bark had shown least colonization. The endophytic diversity was found higher in monsoon season followed by winter and least in summer. The endophytic diversity was found higher at Location 3 (Ranibagh) followed by location 1 (BHU) and minimum at location 2 (Rethali). Out of 28 endophytic fungal taxa recovered Colletotrichum gloeosporioides (12.004%) was found most dominant taxa followed by Curvularia sp. (8.168%), Alternaria alternata (6.634%), Aspergillus niger (6.273%) and Stenella sp. (6.002%), whereas Daldinia sp. (0.316%) followed by Veronaea sp. (0.406%), Phoma putaminum (0.903%), Scytalidium sp. (0.903%) and Aspergillus terreus (1.038%) were recorded as a rare/or incidental taxa. The recovery of rare and incidental species indicates adequacy of sampling size as well as isolation and sterilization protocol adopted in this study.

Présentation et version intégrale (Shodhganga)