Pyomelanin from Pseudoalteromonas lipolytica reduces biofouling.

Zhenshun Zeng,Jin‐Long Yang,Xiaoxue Wang,Xing‐Pan Guo,Baiyuan Li,Pengxia Wang,Xingsheng Cai

doi:10.1111/1751-7915.12773

Abstract

SummaryMembers of the marine bacterial genus Pseudoalteromonas are efficient producers of antifouling agents that exert inhibitory effects on the settlement of invertebrate larvae. The production of pigmented secondary metabolites by Pseudoalteromonas has been suggested to play a role in surface colonization. However, the physiological characteristics of the pigments produced by Pseudoalteromonas remain largely unknown. In this study, we identified and characterized a genetic variant that hyperproduces a dark‐brown pigment and was generated during Pseudoalteromonas lipolytica biofilm formation. Through whole‐genome resequencing combined with targeted gene deletion and complementation, we found that a point mutation within the hmgA gene, which encodes homogentisate 1,2‐dioxygenase, is solely responsible for the overproduction of the dark‐brown pigment pyomelanin. In P. lipolytica, inactivation of the hmgA gene led to the formation of extracellular pyomelanin and greatly reduced larval settlement and metamorphosis of the mussel Mytilus coruscus. Additionally, the extracted pyomelanin from the hmgA deletion mutant and the in vitro‐synthesized pyomelanin also reduced larval settlement and metamorphosis of M. coruscus, suggesting that extracellular pyomelanin released from marine Pseudoalteromonas biofilm can inhibit the settlement of fouling organisms.

Highlights

Marine biofouling communities are surface-dwelling communities composed of all types of marine bacteria, invertebrates and diatoms, and interactions among these organisms govern the nature of biofouling communities (Mieszkin et al, 2013; Lee et al, 2014; Dang and Lovell, 2016)
The extracted pyomelanin from the hmgA deletion mutant and the in vitrosynthesized pyomelanin reduced larval settlement and metamorphosis of M. coruscus, suggesting that extracellular pyomelanin released from marine Pseudoalteromonas biofilm can inhibit the settlement of fouling organisms
Pseudoalteromonas spp. possess important features that have drawn increasing interest from researchers in the ecological and pharmaceutical sciences: (i) they are often found in association with eukaryotic hosts, including marine phytoplankton, sponges, mussels, scallops, tunicates and corals (Holmstrom and Kjelleberg, 1999); (ii) they produce a variety of biologically active extracellular compounds, including pigmented secondary metabolites, extracellular enzymes and extracellular polysaccharide (EPS) (Kalinovskaya et al, 2004; Bowman, 2007)

Summary

Introduction

Marine biofouling communities are surface-dwelling communities composed of all types of marine bacteria, invertebrates and diatoms, and interactions among these organisms govern the nature of biofouling communities (Mieszkin et al, 2013; Lee et al, 2014; Dang and Lovell, 2016). In September 2008, the use of organotin compounds was banned due to their adverse effects on nontarget marine organisms and ecological environments. Pseudoalteromonas spp. possess important features that have drawn increasing interest from researchers in the ecological and pharmaceutical sciences: (i) they are often found in association with eukaryotic hosts, including marine phytoplankton, sponges, mussels, scallops, tunicates and corals (Holmstrom and Kjelleberg, 1999); (ii) they produce a variety of biologically active extracellular compounds, including pigmented secondary metabolites, extracellular enzymes and extracellular polysaccharide (EPS) (Kalinovskaya et al, 2004; Bowman, 2007). Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

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