Abstract
Infesting
Fusarium
species isolated from banana fruit samples were identified and quantified by morphological, mycotoxicological and molecular tools. A total of 19
Fusarium
isolates were obtained:
F. semitectum
was most predominant (26%), followed by
F. proliferatum
(16%),
F. circinatum
(16%),
F. chlamydosporum
(10.5%),
F. solani
(10.5%),
F. oxysporum
(10.5%) and
F. thapsinum
(5%). Fumonisin B1, deoxynivalenol and zearalenone contents were assayed by high-performance liquid chromatography (HPLC). Seventeen isolates, belonging to
F. chlamydosporum
,
F. circinatum
,
F. semitectum
,
F. solani
,
F. thapsinum
,
F. proliferatum
and
Fusarium
spp., produced mycotoxins when cultured on rice medium. Fumonisin was produced by all of the studied
Fusarium
isolates, except
F. oxysporum
, at a concentration of over 1 μg
/
mL.
F. citrinium
isolates 4 and 5 and
F. solani
isolate 3 were the most potent producers of deoxynivalenol. We compared the 19
Fusarium
isolates based on the bands amplified by 10 microsatellite primers. Of these, seven primers, (TCC)5, (TGG)5, (GTA)5, (ATG)5, (TAC)5, (TGC)5 and (TGT)5, yielded a high number of bands and different mean number of alleles. The similarity level between isolates was calculated using a simple matching coefficient. Dendrograms were constructed by the unweighted pair-group method with arithmetical averages (UPGMA). Two main clusters were observed. The interspecific genetic similarity between
Fusarium
spp. isolates was between 40% and 58% and the intraspecific similarity from 58% to 100%, indicating a high degree of genetic diversity in the tested isolates. Some unexpected genetic similarities were observed among the isolates, indicating non-agreement between morphological and molecular identification of the isolates.