Light-induced conidiation of Trichoderma spp. strains is accompanied by development-dependent changes in the Ca2+ binding to cell walls

The effect of light on the Ca2+ binding to mycelia and cell walls isolated from aerial mycelia of three strains of Trichoderma spp. was studied. Measurements of the total Ca2+ content in mycelium, and Ca2+ bound to cell walls isolated from aerial mycelium by two independent methods showed that the light-induced formation and maturation of conidia in Trichoderma spp. is accompanied by an increased Ca2+ deposition in mycelia and cell walls. Moreover, the cultivation of T. atroviride F-534 in the presence of 45Ca2+ under circadian illumination showed that radioactivity was exclusively localized in the light-induced conidial rings of aerial mycelium. The fluorescence microscopy of chlortetracycline-stained mycelia showed that the major fraction of Ca2+ was accumulated in conidia and fructification structures, or some intracellular compartments in T. atroviride F-534 grown under circadian illumination, while only a limited amount of Ca2+ was associated with hyphal surfaces. In addition, the study of 45Ca2+ bin...