Abstract
Entomopathogenic fungi proliferate in insect hemolymph by using host nutrients after penetrating the cuticle. To improve the virulence of the locust specific fungus, Metarhizium acridum, we genetically modified the fungus to overexpress ATM1, an endogenous hydrolase of trehalose, which is the main carbon source in insect hemolymph. Compared with the wild-type strain, Metarhizium acridum overexpressing ATM1 gene secreted more acid trehalase into locust hemolymph. The trehalose concentrations in locusts infected with the ATM1-overexpressing strain were 5.5 and 6.1 mmol/l, lower than that in locusts infected with the wild-type strain at 3 and 5 days post-inoculation, representing 44.5 and 60.7 % reduction, respectively. Correspondingly, overexpressing ATM1 accelerated the growth of Metarhizium acridum in host hemolymph, and the dose causing 50 % mortality (LD50) of the ATM1-overexpressing strain was reduced by 8.3-fold compared with the wild-type strain, suggesting that increasing the utilization of host nutrients by pathogens could be a promising way to improve the virulence of biopesticides based on parasites of pests.
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Acknowledgments
This work was supported by a grant from the High Technology Research and Development Program (863) of China (No. 2011AA10A204), the Natural Science Foundation Project of CQ CSTC (No. CSTC2012 JJB 80002), and the Natural Science Foundation of China (No. 31071730).
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The authors declared that they have no competing interests.
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Guoxiong Peng and Kai Jin contributed equally to this work.
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Peng, G., Jin, K., Liu, Y. et al. Enhancing the utilization of host trehalose by fungal trehalase improves the virulence of fungal insecticide. Appl Microbiol Biotechnol 99, 8611–8618 (2015). https://doi.org/10.1007/s00253-015-6767-y
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DOI: https://doi.org/10.1007/s00253-015-6767-y