First assessment of the anti-cyanobacterial potentialities of the invasive weed Verbesina encelioides against Microcystis aeruginosa growth

Abstract

This work aims to assess the anti-cyanobacterial potentialities of the invasive weed Verbesina encelioides against Microcystis aeruginosa growth. In an experimental bioassay, the aqueous extract of the aerial parts of V. encelioides (AEVE) was tested to investigate its activity on M. aeruginosa growth. Several growth parameters and physiological indicators were assessed. To reveal the potentially allelochemicals, phenolic and flavonoid contents were quantified in AEVE. Results demonstrated that AEVE inhibit the growth of M. aeruginosa in a concentration dependent way. Furthermore, under both highest concentration of AEVE (0.75 and 1 mg/mL), the inhibitory rate (IR) reaches 71% and 79% only after 4 d (d) of experimentation, respectively. The highest IR (93%) was achieved at the highest concentration (1 mg/mL) on 12-d. Thus, the inhibition rates were confirmed by powerful IC50 and IC90 values (0.37 and 0.8 mg/mL), respectively. Additionally, during the experimental period, all four-treatment groups (0.25-1 mg/mL) showed a significant decrease in the content of Chlorophyll-a and carotenoids compared to the control. Overall, the results demonstrate the anti-cyanobacterial effect of AEVE on Microcystis growth. Moreover, the invasive weed V. encelioides might be proposed as a potential environmentally friendly anti-cyanobacterial agent to control Microcystis blooms in the eutrophic water bodies.