Voltage-regulated short-term activation of adenylyl cyclase effected by phytochrome in the lichen Evernia prunastri (L.) Ach.

Red irradiation of the tip of a thallus strip from the lichen Evernia prunastri increases adenylyl cyclase activity within 5 s of lighting as well as enhances K+ efflux that is not balanced by H+, Na+, or Ca2+ influxes. Both effects are reversed by far-red following red light and seem to be simultaneous, but not related consequences of P-r photoconversion to P-fr in the algal membrane. Signal induced by red light is translocated from the tip to the dark-maintained bottom of a Lichen strip, although this translocation requires at least 15 s to be related to adenylyl cyclase activation. Transduction is related to the decrease of the electronegativity of the voltage difference between the tip and the bottom of lichen strips. A supply of exogenous CTP to thallus samples does not activate adenylyl cyclase for time periods lower than 1 min.