Role of the Putative Polysaccharide Deacetylase BA1836 from B. anthracis in Spore Development and Germination

Abstract

Putative and known polysaccharide deacetylases (PDAs) from B. anthracis have key roles in resistance to host lysozyme, stabilization of the cell wall, biogenesis of peptidoglycan (PG) and for neutral polysaccharide modification and attachment to PG. Here we elucidated the physiological role of the puta-tive PDA BA1836 from B. anthracis. The ba1836 gene was expressed upon entrance into the stationary phase of growth and enhanced during the early stages of sporulation. The Δba1836 knockout strain had normal growth rate, did not exhibit any significant alterations in PG pattern of stationary phase cells and was not sensitive to lysozyme, but showed a defect in cell separation. Strikingly, the Δba1836 mutant strain exhibited a severe delay in spore development although mature spores were ultimately developed and had normal morphology. Additionally, digestion of Δba1836 mutant spore PG with mutanolysin produced an almost identical muropeptide pattern compared to peptidoglycan from wild type spores, although the amount of all muropep-tides was significantly reduced. Finally, knockout spores exhibited a lower germination rate. To our knowledge, BA1836 has a unique role, among the presently characterized PDAs from B. anthracis, in spore development and germination.