Abstract
BackgroundSharp increases in food production worldwide are attributable to agricultural intensification aided by heavy use of agrochemicals. This massive use of pesticides and fertilizers in combination with global climate change has led to collateral damage in freshwater systems, notably an increase in the frequency of harmful cyanobacterial blooms (HCBs). The precise mechanisms and magnitude of effects that pesticides exert on HCBs formation and proliferation have received little research attention and are poorly constrained.ResultsWe found that azoxystrobin (AZ), a common strobilurin fungicide, can favor cyanobacterial growth through growth inhibition of eukaryotic competitors (Chlorophyta) and possibly by inhibiting cyanobacterial parasites (fungi) as well as pathogenic bacteria and viruses. Meta-transcriptomic analyses identified AZ-responsive genes and biochemical pathways in eukaryotic plankton and bacteria, potentially explaining the microbial effects of AZ.ConclusionsOur study provides novel mechanistic insights into the intertwined effects of a fungicide and eutrophication on microbial planktonic communities and cyanobacterial blooms in a eutrophic freshwater ecosystem. This knowledge may prove useful in mitigating cyanobacteria blooms resulting from agricultural intensification.
Highlights
Sharp increases in food production worldwide are attributable to agricultural intensification aided by heavy use of agrochemicals
Toxicity of AZ on green algae and cyanobacteria Model cyanobacterium M. aeruginosa as well as a common green alga C. pyrenoidosa were used to investigate the toxicity of AZ on green algae and cyanobacteria
Growth of M. aeruginosa was not suppressed by the range of AZ concentrations during the 7-day treatment (Fig. 1a), while C. pyrenoidosa growth was inhibited by approximately 9.2–30% at the three tested AZ concentrations after 7 days (Fig. 1a)
Summary
Sharp increases in food production worldwide are attributable to agricultural intensification aided by heavy use of agrochemicals This massive use of pesticides and fertilizers in combination with global climate change has led to collateral damage in freshwater systems, notably an increase in the frequency of harmful cyanobacterial blooms (HCBs). This massive use of pesticides and inorganic fertilizers in combination with global climate change has led to extensive collateral damage in aquatic ecosystems, most notably an increase in the frequency of harmful cyanobacterial blooms (HCBs) [1, 2]. Eukaryotic algae and fungi are sensitive to AZ, compared to cyanobacteria, potentially affecting microbial community structure and enhancing cyanobacterial growth [20]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
