The reproductive cycle of cyanophage LPP1-G in Plectonema boryanum and its dependence on photosynthetic and respiratory systems

The intracellular stages of the cyanophage LPP1-G reproductive cycle were established through mechanical burst of infected Plectonema cells. The stages consist of an initial eclipse period (3 hours), followed by intracellular maturation and, finally, lysis of the host cells with release of progeny at the end of the latent period. By excluding or inhibiting photosynthesis or respiration of the host, completion of the reproductive cycle at the maximal burst size (300-400 PFU/infected cell) was found to be dependent on photophosphorylation during the eclipse period. This photophosphorylation can be mediated by cyclic photophosphorylation. In the presence of respiration alone, the burst size is 8% of the maximal burst size and the duration of the cycle is greatly prolonged. The fact that the cyanophage can multiply in Plectonema boryanum without external carbon source is discussed.