Ramanujan Auditorium

Combating environmental stresses: Evolution from ancient cyanobacteria to modern day organisms

Hema Rajaram

BARC Mumbai

Cyanobacteria are one of the most ancient organisms to have inhabited the earth, having been reported to be around for over 2.8 billion years. In order to endure the prevailing conditions at that time, cyanobacteria evolved a multitude of protective mechanisms regulated by more than one regulatory element in most cases. Also, the regulators identified were found to be global regulators for multiple stress responses as against a narrow window of regulated proteins in modern day bacteria. Due to the ease of genetic manipulation techniques and faster growth of mesophiles, majority of the work on abiotic stress response has been carried in mesophiles such as Escherichia coli, Bacillus subtilis, Salmonella etc. As genetic manipulation techniques were made available for some of the cyanobacteria such as the unicellular Synechocystis PCC6803, Synechococcus PCC7942 and the filamentous Nostoc PCC7120, it opened a minefield of information on abiotic stress responses. In my talk I will take you through the journey of abiotic stress response in Nostoc PCC7120 and relate it to what was identified earlier in other bacteria and even higher eukaryotes, to try and bring out the evolution of some of these genes from ancient cyanobacteria to modern day organisms.