Exposing Metarhizium acridum mycelium to visible light up-regulates a photolyase gene and increases photoreactivating ability

Metarhiziun acridum is an entomopathogen currently used against acridids. We have previously reported that exposing mycelium to visible light increases M. acridum tolerance to ultraviolet-B (UV-B) radiation. Here we evaluated if light could also increase tolerance to ultraviolet-C (UV-C) radiation. We observed that, as opposed to UV-B radiation, light did not increase tolerance to UV-C radiation under dark repair conditions. However, light did increase tolerance to UV-C radiation if photoreactivating light was present after UV-C exposure. Quantitative PCR experiments revealed that light up-regulates a photolyase gene. This is the first report showing that light regulates photoreactivating ability in M. acridum. (AU)