Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella.

Pest management science 2021 Jul

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Previous genetic pest management (GPM) systems in diamondback moth (DBM) have relied on expressing lethal proteins ('effectors') that are 'cell-autonomous', that is, they do not leave the cell in which they are expressed. To increase the flexibility of future GPM systems in DBM, we aimed to assess the use of a non-cell-autonomous, invertebrate-specific, neurotoxic effector - the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions. Expression of AaHIT caused a 'shaking/quivering' phenotype that could be repressed by provision of an antidote (tetracycline): a phenotype consistent with the AaHIT mode-of-action. This effect was more pronounced when AaHIT expression was driven by the Hr5/ie1 promoter (82.44% of males, 65.14% of females) rather than Op/ie2 (57.35% of males, 48.39% of females). Contrary to expectations, the shaking phenotype and observed fitness costs were limited to adults in which they caused severe reductions in mean longevity (-81%) and median female fecundity (-93%). Quantitative polymerase chain reactions of AaHIT expression patterns and analysis of piggyBac-mediated transgene insertion sites suggest that restriction of the observed effects to the adult stages may be due to the influence of the local genomic environment on the tetO-AaHIT transgene. We demonstrated the feasibility of using non-cell-autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Citation

Tim Harvey-Samuel, Xuejiao Xu, Erica Lovett, Tarig Dafa'alla, Adam Walker, Victoria C Norman, Ruth Carter, Joss Teal, Luxziyah Akilan, Philip T Leftwich, Christine M Reitmayer, Hamid A Siddiqui, Luke Alphey. Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella. Pest management science. 2021 Jul;77(7):3154-3164