“cAMP depletion negatively affects heat stress tolerance in tobacco BY-2 cells”

Cyclic AMP is an important second messenger in all living organisms; however its existence and its role in plants has been debated for long time. Nowadays it is clear that also in plants, cAMP is involved in several physiological processes, including cell cycle regulation, seed germination, growth and reorientation of the pollen tube. It has also been reported that cAMP is involved in the activation of defence mechanisms in response to biotic and abiotic stresses. In order to verify the involvement of cAMP in plant stress response the effect of moderate heat stress (35°C) in wild type and transgenic tobacco BY-2 cells, with reduced intracellular level of cAMP (cAS cells), has been studied. The obtained results show that heat stress negatively affects cell growth inhibiting cell cycle progression and cell expansions and increasing cell death. cAMP depletion makes tobacco BY-2 cells more susceptible to heat stress determining an increase in cell death. The involvement of heat shock proteins and antioxidants in determining the high susceptibility of cAS cells to heat stress has been also studied and discussed