Nutritional stress affects the tsetse fly's immune gene expression

Area of Science:

• Vector biology
• Insect immunology
• Parasitology

Background:

• Tsetse fly (Glossina spp.) refractoriness impacts trypanosome infection establishment.
• Nutritional stress, specifically starvation, increases tsetse fly susceptibility to trypanosomiasis.
• Tsetse fly immune defense mechanisms play a crucial role in controlling infections.

Purpose of the Study:

• To investigate the impact of starvation on baseline and induced gene expression of antimicrobial peptides (AMPs) in tsetse flies.
• To determine how nutritional stress affects the tsetse fly's immune response to bacterial and trypanosomal challenges.
• To elucidate the role of AMP gene expression in tsetse fly susceptibility to trypanosome infection.

Main Methods:

• Quantitative analysis of attacin, defensin, and cecropin gene expression in tsetse flies under different nutritional states.
• Exposure of tsetse flies to bacterial (Escherichia coli) and trypanosomal (Trypanosoma congolense, Trypanosoma brucei) challenges.
• Measurement of AMP gene expression levels following nutritional stress and pathogen challenge.

Main Results:

• Starvation significantly reduced baseline AMP gene expression (attacin, cecropin) in newly emerged tsetse flies.
• Only non-starved, older flies exhibited increased AMP gene expression in response to trypanosome challenge within five days.
• Trypanosoma brucei bloodstream forms elicited a stronger immune response in non-starved flies.

Conclusions:

• Nutritional stress-induced downregulation of immune genes may increase tsetse fly susceptibility to trypanosome infections.
• Reduced baseline immune gene expression in young flies and blunted responses in older flies contribute to increased susceptibility.
• Understanding these immune modulations is critical for controlling tsetse-transmitted trypanosomiasis.