Organizing co mmittee

 
 

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Poster presentation 
215 
CRUDE EXTRACTS ANTIBACTERIAL AND ANTIFUNGAL ACTIVITY OF 
SIX FUNGAL ISOLATES FROM ORCHIDS Zeuxine strateumatica AND 
Spiranthes hongkongensis 
N. Bibikov
1
, F. Eshboev
2 
 
1) Lomonosov Moscow State University, Moscow, Russia 
2) S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of 
the Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent 
 
Interest towards antimicrobial activity of plant-associated fungi is explained by its 
unpredictable strain-specificity and influent on plant’s medical properties (Gouda et al., 
2016). Studies of fungal microbiome in previously unexplored plant hosts or locations 
bring strains with activity often conditioned by presence of novel chemical compounds 
(Singh et al, 2021). Thus, studying activity of unusual isolates has considerable 
potential for application in medicine and pharmacology. 
Six strains of endophytic fungi were isolated from orchids 
Zeuxine strateumatica 
and 
Spiranthes hongkongensis 
collected in Shenzhen, China. Cultures were isolated by 
placing root fragments on agar plates. Using ITS region sequencing isolated fungi were 
identified as 
Ceratobasidium 
sp
1
, 
Curvularia lunata, Scytalidium circinatum 
from 
Z. 
strateumatica 
and
Ceratobasidium 
sp
2
, 
Nigrospora 
sp., 
Talaromyces 
sp. from 
S. 
hongkongensis
. Among six isolates four are ascomycetous endophytes and two orchid 
mycorrhizal strains of genus 
Ceratobasidium. 
Ethyl acetate extracts of the fungi were 
prepared, dried, and redissolved in methanol. Antimicrobial activity was tested using 
disc-diffusion method against five test cultures: gram-positive bacteria 
Bacillus subtilis 
and 
Staphylococcus aureus
, gram-negative bacteria 
Escherichia coli 
and 
Pseudomonas 
aeruginosa
and 
Candida albicans 
yeast. 
Ascomycetous endophytes show activity against test strains. The broadest activity is 
shown by 
Talaromyces 
sp. isolate against all test cultures. The highest activity is shown 
by 
S. circinatum 
strain against three bacterial strains. Mycorrhizal fungi show no 
activity against test cultures (see table 1). 
Table 1 
Diameter of inhibition zones of studied isolates. N/A – activity not detected 
Inhibition zone diameter, mm 
B. subtilis 
S. aureus E. coli P. aeruginosa C. albicans 
Ceratobasidium 
sp
1
 
N/A