Photostimulation of Hypocrea atroviridis growth occurs due to a cross-talk of carbon metabolism, blue light receptors and response to oxidative stress.
Light is a fundamental abiotic factor which stimulates growth and development of the majority of living organisms. In soil saprotrophic fungi, light is primarily known to influence morphogenesis, particularly sexual and asexual spore formation. Here we present a new function of light, the enhancement of mycelial growth. The photostimulated mycelial growth of the soil fungus Hypocrea atroviridis was detected on 17 (out of 95 tested carbon sources) carbohydrates and polyols, which are metabolically related to cellulose and hemicelluloses, and which are mainly available in the upper soil litter layer. This stimulation depends differently on the function of the two blue light receptor proteins BLR-1 and BLR-2, respectively, BLR-1 being responsible for carbon source selectivity and response to permanent light. Evocation of oxidative stress response in darkness imitates the photostimulation on nine of these carbon sources, and this effect was fully dependent on the function of BLR-1. We conclude that light in combination with the availability of litter-specific carbon sources serves as a signal for the fungus to be above ground, thereby stimulating fast growth in order to produce a maximum of propagules in the shortest time. We further deduce that this process involves oxidative stress response and the two blue light receptor proteins BLR-1 and BLR-2, the former playing the major role.
Friedl
Martina A
MA
Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9-1665, A-1060 Vienna, Austria.
Schmoll
Monika
M
Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9-1665, A-1060 Vienna, Austria.
Kubicek
Christian P
CP
Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9-1665, A-1060 Vienna, Austria.
Druzhinina
Irina S
IS
Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9-1665, A-1060 Vienna, Austria.
D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D035901:Hypocrea / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D025282:Mycelium / Q000254:growth & development / Q000528:radiation effects; D018384:Oxidative Stress; D020283:Photoreceptors, Microbial / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism
D020283:Photoreceptors, Microbial; D011108:Polymers; C024617:polyol; D002244:Carbon