Involvement of Aquaporin in Photomixotrophic Growth of Synechocystis sp. PCC 6803

Abstract

Aquaporin is a water permeable channel, which has been found in bacteria, archaea and eukaryotic cells. The physiological role in cyanobacteria is not fully understood. Synechocystis sp. PCC 6803 genome contains a single member of this gene family. We have previously evaluated the function of Synechocystis aquaporin using Xenopus oocytes expression system and Synechocystis aquaporin deficient mutant on osmoregulation. In this study, we have studied the effect of glucose on the growth of the mutant. The photoautotrophic growth rates of the wild type and the mutant were identical. However, when grown photomixotrophically with glucose, the mutant ceased the growth within 48h. Furthermore, addition of glucose to the mutant resulted in elevated glycogen level, and triggered the structural aberrations and morphological abnormalities. These results demonstrate that aquaporin is essential for the growth of Synechocystis sp. PCC 6803 under photomixotrophic conditions.