Briand Enora, Bormans Myriam, Gugger Muriel, Dorrestein Pieter C, Gerwick William H
UMR CNRS 6553 ECOBIO, University of Rennes 1, 35042, Rennes Cedex, France.
Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA.
Environ Microbiol. 2016 Feb;18(2):384-400. doi: 10.1111/1462-2920.12904. Epub 2015 Jul 21.
The cyanobacteria Microcystis proliferate in freshwater ecosystems and produce bioactive compounds including the harmful toxins microcystins (MC). These secondary metabolites play an important role in shaping community composition through biotic interactions although their role and mode of regulation are poorly understood. As natural cyanobacterial populations include producing and non-producing strains, we tested if the production of a range of peptides by coexisting cells could be regulated through intraspecific interactions. With an innovative co-culturing chamber together with advanced mass spectrometry (MS) techniques, we monitored the growth and compared the metabolic profiles of a MC-producing as well as two non-MC-producing Microcystis strains under mono- and co-culture conditions. In monocultures, these strains grew comparably; however, the non-MC-producing mutant produced higher concentrations of cyanopeptolins, aerucyclamides and aeruginosins than the wild type. Physiological responses to co-culturing were reflected in a quantitative change in the production of the major peptides. Using a MS/MS-based molecular networking approach, we identified new analogues of known classes of peptides as well as new compounds. This work provides new insights into the factors that regulate the production of MC and other secondary metabolites in cyanobacteria, and suggests interchangeable or complementary functions allowing bloom-forming cyanobacteria to efficiently colonize and dominate in fluctuating aquatic environments.
蓝藻微囊藻在淡水生态系统中大量繁殖，并产生包括有害毒素微囊藻毒素（MC）在内的生物活性化合物。这些次生代谢产物通过生物相互作用在塑造群落组成方面发挥着重要作用，尽管它们的作用和调控模式尚不清楚。由于天然蓝藻种群包括产毒菌株和非产毒菌株，我们测试了共存细胞产生的一系列肽的产生是否可以通过种内相互作用来调节。通过一个创新的共培养室以及先进的质谱（MS）技术，我们监测了产MC的微囊藻菌株以及两个不产MC的微囊藻菌株在单培养和共培养条件下的生长情况，并比较了它们的代谢谱。在单培养中，这些菌株生长情况相当；然而，不产MC的突变体产生的蓝藻肽、铜绿环肽和铜绿菌素的浓度高于野生型。对共培养的生理反应反映在主要肽产生的定量变化上。使用基于MS/MS的分子网络方法，我们鉴定出了已知肽类的新类似物以及新化合物。这项工作为调节蓝藻中MC和其他次生代谢产物产生的因素提供了新的见解，并表明了可互换或互补的功能，使形成水华的蓝藻能够在波动的水生环境中有效地定殖和占据主导地位。
