Purpose: To isolate and identify the fungal endophytes of
Fagopyrum tataricum and assess their
antimicrobial activity.
Methods: The fungal isolates were identified according to their morphological characters and internal
transcribed spacer (ITS) sequence analysis. Both broth-dilution-colorimetric assay and spore
germination test were employed to assess the antimicrobial activity of fungal mycelia extracts..
Results: A total of 72 endophytic fungal isolates were successfully obtained from the healthy tissues of
F. tataricum. On the basis of their morphological and molecular characteristics, thirteen distinct fungal
isolates were identified, and belonged to
Alternaria
,
Bionectria
,
Botryosphaeria
,
Fusarium
,
Guignardia
,
Nectria
,
Neonectria
,
Phomopsis
,
Pseudocercospora
and
Verticillium
spp. Of these,
Pseudocercospora
owned the maximum colonization frequency (15.3 %), next for
Alternaria (12.5 %) and
Neonectria (11.1
%). Through antimicrobial screening assays, six endophytes (Fataf-4, 6, 9, 11, 12 and 15) were active
against
Bacillus subtilis
,
Staphylococcus aureus
,
Agrobacterium tumefaciens
,
Escherichia coli
and Pseudomonas lachrymans, and their minimal inhibitory concentration (MIC) ranged from 0.125 to 2.00
mg/mL. Furthermore, the endophytes, Fataf-9 and Fataf-11, also displayed strong inhibitory activity on
the spore germination of
F. oxysporum f. sp.
vasinfectum
and
F. oxysporum f. sp.
cucumerinum
, and
their median effective inhibitory concentration (IC
50) was 0.356, 0.463, 0.451 and 0.489 mg/mL,
respectively.
Conclusion: The endophytic fungi of
F. tataricum appear to be diverse and promising in their
antimicrobial activity, and may represent a potential source of antibiotics for agriculture and/or
pharmaceutical applications.
