Cyanopeptides restriction and degradation co-mediate microbiota assembly during a freshwater cyanobacterial harmful algal bloom (CyanoHAB). (15th July 2022)

• Record Type: Journal Article
• Authors: Gao, Han; Zhao, Ze; Zhang, Lu; Ju, Feng
• Is Part Of: Water research. Volume 220(2022)
• Publication Date: 2022-07-15
• Subjects: Cyanobacterial harmful algal blooms -- Cyanopeptides -- Microbial community assembly -- High-throughput sequencing -- Eutrophication -- Taihu; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118674
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Cyanopeptides of emerging ecotoxicological concern were detected in Taihu. Cyanopeptides were stronger factors than nutrients in driving microbial turnover. Cyanopeptides degradation was co-affected by degraders and microbiological setups. Stochasticity of microbial assembly could be mediated by cyanopeptides. Abstract: Cyanobacterial harmful algal blooms (CyanoHABs) are globally intensifying and exacerbated by climate change and eutrophication. However, microbiota assembly mechanisms underlying CyanoHABs remain elusive. Especially, cyanopeptides, as a group of bioactive secondary metabolites of cyanobacteria, could affect microbiota assembly and ecosystem function. Here, the trajectory of cyanopeptides was followed and linked to microbiota during Microcystis -dominated CyanoHABs in Lake Taihu, China. The most abundant cyanopeptide classes detected included microginin, spumigin, microcystin, nodularin and cyanopeptolin with total MC-LR-equivalent concentrations between 0.23 and 2051.54 ppb, of which cyanotoxins beyond microcystins (e.g., cyanostatin B and nodularin_R) far exceeded reported organismal IC50 and negatively correlated with microbiota diversity, exerting potential collective eco-toxicities stronger than microcystins alone. The microbial communities were differentiated by size fraction and sampling date throughout CyanoHABs, and surprisingly, their variances were better explained by cyanopeptides (19-38%) than nutrients (0-16%). Cyanopeptides restriction (e.g., inhibition) and degradation were first quantitatively verified as the deterministic drivers governing community assembly, with stochastic processes being associated with the interplay between cyanopeptide dynamics and lake microbiota. This study presents an emerging paradigm in which cyanopeptides restriction and degradation co-mediate lake water microbiota assembly, unveiling new insights into the ecotoxicological significance of CyanoHABs to freshwater ecosystems. Graphical Abstract: Image, graphical abstract