A predator-prey interaction between a marine Pseudoalteromonas sp. and Gram-positive bacteria
Bai-Lu Tang, Jie Yang, Xiu‐Lan Chen, Peng Wang, Huilin Zhao, Hai‐Nan Su, Chunyang Li, Yang Yu, Shuai Zhong, Lei Wang, Ian D. E. A. Lidbury, Haitao Ding, Min Wang, Andrew McMinn, Xi‐Ying Zhang, Yin Chen, Yu‐Zhong Zhang
Abstract
Predator-prey interactions play important roles in the cycling of marine organic matter. Here we show that a Gram-negative bacterium isolated from marine sediments (Pseudoalteromonas sp. strain CF6-2) can kill Gram-positive bacteria of diverse peptidoglycan (PG) chemotypes by secreting the metalloprotease pseudoalterin. Secretion of the enzyme requires a Type II secretion system. Pseudoalterin binds to the glycan strands of Gram positive bacterial PG and degrades the PG peptide chains, leading to cell death. The released nutrients, including PG-derived D-amino acids, can then be utilized by strain CF6-2 for growth. Pseudoalterin synthesis is induced by PG degradation products such as glycine and glycine-rich oligopeptides. Genes encoding putative pseudoalterin-like proteins are found in many other marine bacteria. This study reveals a new microbial interaction in the ocean.