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Updated: Jun 12, 2026

Early Detection of Cyanobacterial Blooms and Associated Cyanotoxins using Fast Detection Strategy
Published on: February 25, 2021
Decoding the alkaline salt stress response in toxic cyanobacteria: Insights into toxigenic Microcystis resilience and
Yanwen Zhang1, Yunlu Jia2, Tianli Li2
1Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Abstract:
Amid intensifying climate warming and anthropogenic activities, toxic cyanobacterial blooms continue to proliferate across various aquatic systems, posing emerging risks in salinized-alkalized waters. However, the physiological responses and ecological risks of toxic cyanobacteria under alkaline salt stress remain poorly understood. This study examined four Microcystis strains with microcystins (MCs) under alkaline salt stress to elucidate their survival strategies. All four MCs-producing Microcystis strains exhibited growth inhibition under alkaline salt stress, with strain-specific tolerance levels ranked by EC50 as: Microcystis sp. FACHB-1196 (Mainly producing MC-YR) > Microcystis ichthyoblabe FACHB-1411 (Mainly producing MC-LR, MC-RR, MC-YR, MC-LW, MC-LY, MC-LF and MC-LA) > Microcystis ichthyoblabe FACHB-1412 (Mainly producing MC-LY, LF and LA) > Microcystis sp. FACHB-1178 (Mainly producing MC-RR). Notably, extracellular MCs release was significantly enhanced in a toxin-type-dependent manner, with the MC-RR-producing Microcystis sp. FACHB-1178 showing the most rapid and elevated response, peaking at 677.97 ng/mL. Physiological and transcriptomic analyses at strain-specific EC50 and EC80 levels revealed four major response patterns: growth and pigment responses; photosynthesis-related responses; redox homeostasis, membrane stability, and osmotic-metabolic reprogramming; and MCs-related responses. Early-stage responses included short-term photosynthetic adjustment, translational remodeling, and osmo-/ion-regulatory transcriptional changes, whereas prolonged stress was associated with progressive impairment of photosynthetic performance, oxidative and membrane perturbation, soluble protein decline, and strain-specific EPS responses. In parallel, key mcy genes were upregulated, and extracellular MCs changed in a strain-specific manner. Together, these results show that alkaline salt stress affects Microcystis through multiple interacting processes rather than a single pathway, and highlight substantial heterogeneity in short-term acclimatory responses among toxigenic strains. These findings provide integrated insight into bloom toxicity risk in salinizing and alkalinizing inland waters.
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