Current Genetics

, Volume 61, Issue 3, pp 253–261 | Cite as

Stress is the rule rather than the exception for Metarhizium

  • Brian LovettEmail author
  • Raymond J. St. Leger
Research Article


The insect pathogenic plant root symbiont Metarhizium experiences many situations that restrict its growth whether living in host insects or on plant roots. These include a range of physical, chemical and biological effects involving UV and extremes of temperature, pH, nutrient availability, toxic metals and other pollutants, and insect host defenses such as production of reactive oxygen species. Aside virulence, the major impediment to reliable pest control with Metarhizium is its sensitivity to UV and temperature extremes. However, increased levels of stress tolerance can be engineered into Metarhizium quite simply by reprogramming the expression of single downstream endogenous genes. For example, overexpression of RNA-binding proteins resulted in Metarhizium with increased tolerance to cold stress, overexpression of photolyase increased tolerance to UV, and increased expression of heat shock protein 25 improved tolerance to several stress conditions, including heat, and osmotic pressure. Conversely, disruption of these genes greatly reduced persistence, and could provide genetic containment for genetically engineered hypervirulent strains.


Metarhizium Stress response genes Heat shock Cold response UV stress Osmosensor Mitogen Activated protein (MAP) kinase pathway Colony deterioration Genetic engineering 



The work reported here was supported in part by Biotechnology Risk Assessment Grant Program competitive Grant No. 2011-33522-30742 and by USDA CSREES Grant 2010-65106-20580 from the USDA National Institute of Food and Agriculture. This review article was supported in part by a grant from São Paulo Research Foundation (FAPESP) of Brazil #2014/01229-4.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of EntomologyUniversity of MarylandCollege ParkUSA

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