Molecular phylogeny, diversity and bioprospecting of endophytic fungi associated with wild ethnomedicinal North American plant Echinacea purpurea (Asteraceae)

Authors: CARVALHO, CAMILA - Universidade Federal De Minas Gerais; Wedge, David; Cantrell, Charles; SILVA-HUGHES, ALICE - Universidade Federal De Minas Gerais; Pan, Zhiqiang - Peter; MORAES, RITA - University Of Mississippi; MADOXX, VICTOR - University Of Mississippi; ROSA, LUIZ - Universidade Federal De Minas Gerais

Submitted to: Chemistry and Biodiversity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2016
Publication Date: 6/11/2016
Citation: Carvalho, C.R., Wedge, D.E., Cantrell, C.L., Silva-Hughes, A.F., Pan, Z., Moraes, R.M., Madoxx, V.L., Rosa, L.H. 2016. Molecular phylogeny, diversity and bioprospecting of endophytic fungi associated with wild ethnomedicinal North American plant Echinacea purpurea (Asteraceae). Chemistry and Biodiversity. 13:918-930 DOI: 10.1002/cbdv.201500299.

Interpretive Summary: Endophytic fungi represent a particular group of microorganism that lives within the vascular tissue and spaces of plant without causing apparent negative effects on the host plant. Many plant species have been shown to shelter interesting endophytic fungal communities which are able of producing antimicrobial, antiparasitic, and antitumor compounds. Among the endophytic groups studied, those recovered from medicinal plants are of particular interest to us because they often produce compounds which appear to play a role in host plant defense or possess unique biologically active metabolites. Eight antifungal extracts were selected for chemical analysis. Forty fatty acids were identified by gas chromatographic analysis. Our results indicated that purple coneflower (Echinacea purpurea) lives symbiotically with different endophytic fungi that are able to produce bioactive fatty acids and aromatic compounds active against important plant pathogenic fungi. The detection of the different fatty acids and aromatic compounds produced by endophytic fungi associated with wild purple coneflower suggests that it may have intrinsic mutualistic resistance against some plant pathogen in its natural environment.

Technical Abstract: The endophytic fungal community associated with the wild ethnomedicinal North American plant Echinacea purpurea was investigated as well as its potential for providing antifungal compounds against plant pathogenic fungi. A total of 233 endophytic fungal isolates were obtained and classified into 42 different taxa of 16 genera using molecular methods. The most frequent colonisers were Alternaria alternata, Colletotrichum dematium and Stagonosporopsis sp. 2. The endophytic fungal community showed moderate richness and evenness, but high diversity indices. In addition, the rarefaction curve indicated that not all of the diversity was recovered. The extracts of 29 endophytic fungi displayed activities against important phytopathogenic fungi. Eight antifungal extracts were selected for chemical analysis. Forty fatty acids were identified by GC-FID analysis. The compounds (-)-5-methylmellein and (-) (3R)-8-hydroxy-6-methoxy-3,5-dimethyl-3,4-dihydroisocoumarin were isolated from Biscogniauxia mediterranea EPU38CA crude extract. (-)-5-Methylmellein showed weak activity against P. obscurans, P. viticola and F. oxysporum, and caused growth stimulation of C. fragariae, C. acutatum, C. gloeosporioides and B. cinerea. (-) (3R)-8-Hydroxy-6-methoxy-3,5-dimethyl-3,4-dihydroisocoumarin appeared slightly more active in the microtiter environment than 5-methylmellein. Our results indicate that E. purpurea lives symbiotically with different endophytic fungi, which are able to produce bioactive fatty acids and aromatic compounds active against important phytopathogenic fungi. The detection of the different fatty acids and aromatic compounds produced by the endophytic community associated with wild E. purpurea suggests that it may have intrinsic mutualistic resistance against phytopathogen attacks in its natural environment.