Published in Scientific Papers. Series B, Horticulture, Volume LX
Written by Andreea COȘOVEANU, Cristina Emilia NIȚĂ, Beatrice Michaela IACOMI, Samuel RODRIGUEZ SABINA, Raimundo CABRERA
Endophytic fungi have been isolated from Artemisia austriaca (isolates HRO184, HRO183, HRO169 and HRO115), A. vulgaris (isolate HRO158) and A. thuscula (isolates HLP7, HLP26, HLP27, and HLP44) in Romania and La Palma, Canary Islands, Spain. The strains were studied for their bioactivity against phytopathgenic fungi (Alternaria alternata, Alternaria dauci, Alternaria brassicicola, Fusarium oxysporum, Fusarium solani, Fusarium moniliforme, Sclerotinia sclerotiorum, Botrytis cinerea, Phoma sp., Geotrichum sp. and Cladosporium sp.) using dual culture, agar dilution and volatile compounds (VOC) techniques. In dual culture assays, all Canarian isolates were strong antagonists of at least one pathogen and two Romanian isolates, HRO169 against S. sclerotiorum and HRO158 against A. brassicicola. In VOC assays, a difference was observed between slow growth isolates (1-2 cm/week) and normal growth (4-5 cm/week), therefore three moments of fungal pathogen inoculation were used: after three and five days from the endophyte inoculation. The highest inhibition gradually produced by the volatile compounds was observed with HLP44 isolate against Cladosporium sp. (%I = 31.5) at 7th day. Solvent extracts were obtained from HRO169, HRO158, HLP44, HLP27 and HLP7 isolates and further two of them (HRO158 and HLP44) were fractionated using vacuum-liquid chromatography eluted with n-hexane:EtAc:MeOH gradient to give seven fractions. Extract obtained from HLP44 isolate strongly inhibited A. brassicicola (%I = 44), F. moniliforme (%I =52.78) and S. sclerotiorum (%I = 50.4), at 0.1mg ml-1. Ethyl acetate fraction was the most active against A. brassicicola, F. solani and B. cinerea (%I = 42.68, 59.17 and 49.36, respectively, at 0.1mg ml-1) followed by the EtAc:MeOH (90:10) fraction which also inhibited A. brassicicola and F. solani (%I = 35.83 and 39.53, respectively).
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