The Stress of Fungicides Changes the Expression of Clock Protein CmFRQ and the Morphology of Fruiting Bodies of Cordyceps militaris

Abstract

The physiological, biochemical, and morphological changes brought about by fungi in response to fungicides can undoubtedly bring diversity to fungi. Cordyceps militaris strains TN (mating type genes MAT1-1-1, MAT1-1-2, and MAT1-2-1) and CmFRQ-454 (mating type genes MAT1-1-1 and MAT1-1-2) were treated with non-lethal doses of fungicides amphotericin B, L-cysteine, terbinafine, and 5-fluorocytosine. The results showed that the treatment with amphotericin B, terbinafine, and 5-fluorocytosine promoted an increase in the relative content of clock protein CmFRQ (C. militaris FREQUENCY) in the mycelium of strain TN, while the high concentration of L-cysteine inhibited the expression of CmFRQ in strain TN. These four fungicides could reduce the relative contents of CmFRQ in the mycelium of strain CmFRQ454. The relative contents of CmFRQ in the mycelium of strain TN were increased after removing the four fungicides, but the relative contents of CmFRQ in the mycelium of strain CmFRQ454 were decreased after removing the four fungicides. This indicates that the effect of fungicides on CmFRQ on mycelium was still sustained after removing the stress of fungicides, and the operation of the circadian clock was changed. The fruiting bodies of C. militaris strain TN and CmFRQ-454 were still degenerated to varying degrees after removing amphotericin B, L-cysteine, and terbinafine. However, the fruiting bodies of strain TN after removing 5-fluorocytosine did not show significant degeneration; the fruiting bodies of strain CmFRQ-454 after removing 5-fluorocytosine obtained rejuvenation. These results indicate that the stress of fungicides could lead to the degeneration of fruiting bodies as well as the rejuvenation of fruiting bodies, resulting in the morphological diversity of C. militaris. The increase or decrease of the CmFRQ-454, the main component of the circadian clock, caused by the stress of fungicants, might lead to the differential degeneration of different mating-type strains of C. militaris.