Investigation of effects of some physical and chemical parameters on the heat shock response using recombinant Chlamydomonas reinhardtii strains

In this study, various chemical and physical parameters which could be effective in heat shock response were investigated on C.reinhardtii by using molecular tools. In total 256 transformants were obtained, among them 160 transformants had continuous expression while 96 of them had heat-inducible expression and these transformants were screened for ARS activity qualitatively and quantitatively. Further studies were performed with selected transformants βTub II-32 and HSP70A III-1. As physical parameters the effect of temperature, light intensity and UV-B radiation; as chemical parameters salinity, calcium and calcium chelators and blockers were investigated. To investigate the effect of temperature, the cells were shifted from 23 °C to 35 °C, 37 °C, 40 °C and 42 °C. The heat shock response was induced even at 35 °C. It was determined that above 100mM of calcium concentration ARS activity was increased. In the presence of calcium chelators EGTA and BAPTA, heat stress response was triggered. 100µM lanthanum and 250 µM gadolinium were found effective in decreasing ARS activity. However, verapamil was not effective. It was found that light intensity of 2 000 lux and above increased ARS activity. UV-B and salinity had no effect on ARS activity. All ARS enzyme activity results were compared with the results of RT-qPCR and partially parallel results were obtained. These data obtained with recombinant C. reinhardtii might be important for plant stress and ecological studies.