UV-B induces cell death in the lichen Physcia semipinnata (J.F.Gmel)

We have examined the consequences of Ultraviolet-B (UV-B) irradiation in the thallus of the lichen Physcia semipinnata (J.F.Gmel) in terms of cell viability and apoptotic-like formation. UV-B induced oligonucleosomal DNA fragmentation was detected by TUNEL assay and this is the first study showing DNA fragmentation in thalli. The intensity of TUNEL-positive cells after exposure to UV-B at doses up to 95.9 J/cm² was higher in the photobiont layer than the mycobiont layer.