Analysis of the expression and the activity of the putative alkaline phosphatases in Cyanobacterium Anabaena FACHB709

Cyanobacterial blooms were thought to be initiated by increased availability of phosphorus (P), alkaline phosphatase(AP) play a crucial role in P metabolism. Anabaena FACHB709, a species closely relative to cyanobacterium Anabaena flos-aquae has well-established genetic manipulation system, we have chosen this organism as a model to characterize four genes predicted to encode alkaline phosphatases. We examined cellular physiological responses and transcriptional regulation of these genes after induction of P deficiency. The results showed that the induction of inorganic phosphate deprivation led to cell growth inhibition rather than cell death. Gene phoD2-709 was not transcribed, and other three AP genes were obviously transcribed under normal growth condition. However, under the condition of P starvation, the transcription of the genes were all up-regulated obviously in various degrees. The analysis of total alkaline phosphatase activity were consistent with the the results of transcriptional regulation. These evidence suggested that alkaline phosphatases control the availability of phosphorus by the regulation of these genes at transcription level in Anabaena FACHB709.