Quorum Sensing Is a Language of Chemical Signals and Plays an Ecological Role in Algal-Bacterial Interactions

ABSTRACTAlgae are ubiquitous in the marine environment, and the ways in which they interact with bacteria are of particular interest in the field of marine ecology. The interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape microbial diversity. Although algal-bacterial interactions are well known and studied, information regarding the chemical-ecological role of this relationship remains limited, particularly with respect to quorum sensing (QS), which is a system of stimuli and response correlated to population density. In the microbial biosphere, QS is pivotal in driving community structure and regulating behavioral ecology, including biofilm formation, virulence, antibiotic resistance, swarming motility, and secondary metabolite production. Many marine habitats, such as the phycosphere, harbor diverse populations of microorganisms and various signal languages (such as QS-based autoinducers). QS-mediated interactions widely influence algal-bacterial symbiotic relationships, which in turn determine community organization, population structure, and ecosystem functioning. Understanding infochemicals-mediated ecological processes may shed light on the symbiotic interactions between algae host and associated microbes. In this review, we summarize current achievements about how QS modulates microbial behavior, affects symbiotic relationships, and regulates phytoplankton chemical-ecological processes. Additionally, we present an overview of QS-modulated co-evolutionary relationships between algae and bacterioplankton, and consider the potential applications and future perspectives of QS.KEYWORDS: Algal-bacterial relationshipsbacterioplanktonco-evolutionecological behaviorsphytoplanktonsignal language FundingThis study was supported by the NSFC (41476092), the Basic Research Program (JCYJ20150529164918736), and Key Project of Science and Technology (JSGG20140519113458237, CXZZ20150529165045063) of the Shenzhen Science and Technology Innovation Committee. Funding was also provided by the Woods Hole Center for Oceans and Human Health through the National Science Foundation Grant OCE-1314642 and the National Institute of Environmental Health Sciences Grant 1-P01-ES021923-01.