title: Effects of insect cuticular fatty acids on in vitro growth and pathogenicity of the entomopathogenic fungus Conidiobolus coronatus.
abstract: Eighteen fatty acids identified in the cuticle of three insect species representing differing susceptibilities to C. coronatus infection, were tested for effects on the in vitro growth and pathogenicity of the parasitic fungus. At all applied concentrations (0.1-0.0001% w/v) growth was inhibited by C(16:0), C(16:1), C(18:0), C(18:1), C(18:2), C(18:3), C(20:0) and C(20:1). At high concentrations spore germination was inhibited by C(7:0), C(8:0), C(9:0), C(10:0), C(12:0), C(18:2) and C(18:3) and hyphal growth was merely retarded by C(5:0), C(6:0), C(6:2), C(14:0), C(16:0), C(16:1), C(18:0,) C(18:1), C(20:0) and C(20:1). The presence of C(15:0) at the 0.1% concentration stimulated growth of C. coronatus. Sporulation was inhibited by all concentrations of C(16:0) and C(18-20) fatty acids. Low concentrations of C(5:0), C(6:0), C(6:2) and C(7:0) enhanced sporulation. Fatty acids C(5-12) as well as C(18:3), C(20:0) and C(20:1) decreased the ability of fungal colonies to infect G. mellonella while C(16:1) elevated it thus suggesting that C(16:1) may stimulate production of enzymes involved in the host invasion. Toxicity of metabolites released into incubation medium decreased with varying degrees in the presence of C(6:0), C(6:2,) C(7:0), C(9:0), C(12:0), C(16:1), C(18:2), C(18:3), C(20:0) and C(20:1); other fatty acids had no effect. Further work is needed to analyse the effects of exogenous fatty acids on the C. coronatus enzymes implicated in fungal pathogenicity as well as on the production of insecticidal metabolites.
authors.affiliation: Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, Warsaw, Poland. slawka@twarda.pan.pl
authors.forename: Mieczysława I
authors.initials: MI
authors.lastname: Boguś
authors.forename: Maria
authors.initials: M
authors.lastname: Czygier
authors.forename: Marek
authors.initials: M
authors.lastname: Gołebiowski
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Kedra
authors.forename: Jolanta
authors.initials: J
authors.lastname: Kucińska
authors.forename: Joanna
authors.initials: J
authors.lastname: Mazgajska
authors.forename: Jarosław
authors.initials: J
authors.lastname: Samborski
authors.forename: Wioletta
authors.initials: W
authors.lastname: Wieloch
authors.forename: Emilia
authors.initials: E
authors.lastname: Włóka
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D018533:Biomass; D020092:Conidiobolus / Q000187:drug effects / Q000254:growth & development* / Q000472:pathogenicity* / Q000502:physiology; D005227:Fatty Acids / Q000737:chemistry / Q000494:pharmacology*; D005656:Fungal Proteins / Q000378:metabolism; D009036:Moths / Q000737:chemistry / Q000382:microbiology*; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development; D013172:Spores, Fungal / Q000187:drug effects / Q000502:physiology; D014774:Virulence
chemical_list: D005227:Fatty Acids; D005656:Fungal Proteins