Role of Sll1558 under acid stress condition in the cyanobacterium Synechocystis sp. PCC 6803

Abstract

Sll1558 in Synechocystis sp. PCC 6803 is identified as D-mannose-1-phosphate guanylyltransferase that catalyzes the transfer of D-mannose-1-phosphate to GDP-mannose involved in cell wall biosynthesis. DNA microarray and real-time RT-PCR analysis revealed that relative expression levels of sll1558 were increased by acid stress. Mutants defective in this gene and sll1496, which is a paralog of the gene, were constructed. The deletion mutants of sll1558 were more sensitive to acid stress compared with wild type cells. Compositions of capsular polysaccharide and lipopolysaccharide were compared with wild type and the deletion mutants by silver staining after the SDS-PAGE. It showed different patterns of the bands between the mutant of sll1558 and wild type. It was found that cyt1, mutants of homolog of sll1558 in Arabidopsis thaliana, strongly retarded root growth under acid condition. These results suggest that Sll1558 contribute to cell wall biosynthesis to adapt acid conditions.