Effects of insect cuticular fatty acids on in vitro growth and pathogenicity of the entomopathogenic fungus Conidiobolus coronatus.
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.
Boguś
Mieczysława I
MI
Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, Warsaw, Poland. slawka@twarda.pan.pl
Czygier
Maria
M
Gołebiowski
Marek
M
Kedra
Elzbieta
E
Kucińska
Jolanta
J
Mazgajska
Joanna
J
Samborski
Jarosław
J
Wieloch
Wioletta
W
Włóka
Emilia
E
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
D005227:Fatty Acids; D005656:Fungal Proteins