Antimicrobial activity of endophytic fungi from olive tree leaves.
In this study, the antimicrobial potential of three fungal endophytes from leaves of Olea europaea L. was evaluated and the host plant extract effect in the antimicrobial activity was examined. The volatile compounds produced by endophytes were identified by GC/MS and further correlated with the antimicrobial activity. In potato dextrose agar, both Penicillium commune and Penicillium canescens were the most effective inhibiting Gram-positive and -negative bacteria (up to 2.7-fold compared to 30 µg/mL chloramphenicol), whereas Alternaria alternata was most effective inhibiting yeasts (up to 8.0-fold compared to 25 μg/mL fluconazole). The presence of aqueous leaf extract in culture medium showed to induce or repress the antimicrobial activity, depending on the endophytic species. In the next step, various organic extracts from both A. alternata mycelium and cultured broth were prepared; being ethyl acetate extracts displayed the widest spectrum of anti-microorganisms at a minimum inhibitory concentration ≤0.095 mg/mL. The volatile composition of the fungi that displayed the highest (A. alternata) and the lowest (P. canescens) antimicrobial activity against yeasts revealed the presence of six volatiles, being the most abundant components (3-methyl-1-butanol and phenylethyl alcohol) ascribed with antimicrobial potentialities. Overall the results highlighted for the first time the antimicrobial potential of endophytic fungi from O. europaea and the possibility to be exploited for their antimicrobial agents.
REQUIMTE-LAQV, School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
Cynthia
C
Malhadas
REQUIMTE-LAQV, School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
Ricardo
R
Malheiro
REQUIMTE-LAQV, School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
José Alberto
JA
Pereira
REQUIMTE/Laboratory of Toxicology, Faculty of Pharmacy, Porto University, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
Paula Guedes
PG
de Pinho
REQUIMTE-LAQV, School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal. pbaptista@ipb.pt.
Paula
P
Baptista
D000085:Acetates / Q000737:chemistry; D000528:Alternaria / Q000187:drug effects; D002701:Chloramphenicol / Q000494:pharmacology; D060026:Endophytes / Q000378:metabolism*; D015725:Fluconazole / Q000494:pharmacology; D005658:Fungi / Q000502:physiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D031658:Olea / Q000737:chemistry / Q000382:microbiology*; D010407:Penicillium / Q000378:metabolism; D000439:Pentanols / Q000494:pharmacology; D010626:Phenylethyl Alcohol / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000382:microbiology; D055549:Volatile Organic Compounds / Q000737:chemistry / Q000494:pharmacology; D015003:Yeasts / Q000187:drug effects
D000085:Acetates; D000439:Pentanols; D010936:Plant Extracts; D055549:Volatile Organic Compounds; D002701:Chloramphenicol; C007650:ethyl acetate; D015725:Fluconazole; C029683:isopentyl alcohol; D010626:Phenylethyl Alcohol
Alternaria alternata; Minimum inhibitory concentration; Olea europaea L.; Volatile fraction