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SESSION 2: SECONDARY METABOLITES – BIOCHEMISTRY,
BIOSYNTHESIS, FEED AND FOOD SAFETY
P17 - Semiochemical interactions between toxigenic
Fusarium fungi and insects
T. Y. Gagkaeva, O. P. Gavrilova, I. V. Shamshev, O. G. Selitskaya, E. I.
Savelieva
All-Russian Institute of Plant Protection (VIZR), Sh. Podbelskogo 3, 196608, St.-Petersburg – Pushkin,
Russia
E-mail: t.gagkaeva@yahoo.com
The aim of the study was to evaluate chemical nature and functional abilities of
semiochemical interactions between toxigenic Fusarium fungi and insects. An
analysis of variations of Fusarium fungi (F. graminearum, F. culmorum, F.
cerealis, F. poae, F. sporotrichioides, F. langsethiae) in formation of olfactory
responses of insects (rice weevil Sitophilus oryzae) was performed. The
evaluation of olfactory stimulation with Fusarium fungi on test-insects was carried
out after growing of the strains on two substrates: potato sucrose agar and
autoclaved wheat grains. In the laboratory experiments F. langsethiae and F.
poae strains have shown the clear attractive effect to the tested insects. The
pathogenic to plants F. graminearum and F. culmorum strains have demonstrated
the repellent effect. Generally beetles of rice weevil responded similar reaction to
the cultures of fungal strains growing on both substrates.
The method of solid-phase microextraction was used to clarify the spectra of
volatile organic compounds above the surface of living fungal cultures. Screeningportraits
of metabolomic profiles of Fusarium strains after 7 days of cultivation
were obtained. A characteristic profile of sesquiterpenes, that are isomeric
carbohydrates with molecular mass 204 and are genetically connected with
trichodien, is richest in F. langsethiae in compare with another Fusarium spp. The
culture of F. langsethiae produced maximal amount of trichodien also actively
emitted volatile compounds. Under equilibrium condition of steam above surface
of F. langsethiae, F. sporotrichioides и F. poae cultures were identified
ethylacetate, isobutyl, isoamyl and amyl alcohols. Amylacetate and
isoamylacetate, ethers of acetic acid and corresponding amyl alcohols were found
only in the culture of F. poae. Most likely just these chemicals responsible for a
sweet fruit smell that is typical for this fungus.
The investigation was supported by the project No. 12-04-00927-а of the Russian
Foundation for Basic Research.
Keywords: Fusarium, insects, sesquiterpenes, olfactory stimulation
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