Allelopathic activity of the picocyanobacterium Synechococcus sp. under varied light, temperature, and salinity conditions

Abstract

The impact of environmental factors and mode of action of allelopathic compounds produced by picocyanobacteria on microalgae remains unknown. Therefore, it is essential to characterize allelopathic interactions under different experimental conditions. In this study, the influence of allelopathic activity on the diatom Navicula perminuta was investigated by the addition of cell-free filtrate of picocyanobacterium Synechococcus sp. cultures grown under different light, temperature, and salinity conditions. Temperature affected the most the donor cyanobacterium by increasing its allelopathic activity. The highest decline in growth, fluorescence parameter F v /F m and maximal photosynthesis P m were observed after the addition of cell-free filtrate obtained from Synechococcus sp. grown at 190 mmol photons Á m À2 Á s À1 , 25°C and 8 PSU. These studies indicate for the first time that the picocyanobacterium Synechococcus sp. affect coexisting diatom N. perminuta negatively. It was examined that the Synechococcus sp. reveals allelopathic activity on the photosynthesis and chlorophyll fluorescence, which results in the inhibition of growth of analyzed microalgae. These findings indicate that the production of allelopathic substances by picocyanobacterium is regulated by the availability of environmental factors such as light, temperature, and salinity. Moreover, these results demonstrated that variation in light intensity, water temperature, and salinity should be considered when estimating the potential effects of cyanobacterial allelopathy in aquatic environments.

Assessment of the Allelochemical Activity and Biochemical Profile of Different Phenotypes of Picocyanobacteria from the Genus Synechococcus

“…Several studies have shown a negative effect of the Synechococcus sp. Type 1 filtrates on different phytoplankton species, such as diatom Navicula perminuta [15], filamentous cyanobacteria Nostoc sp. and Phormidium sp.…”

Allelopathic activity of the bloom‐forming picocyanobacterium Synechococcus sp. on the coexisting microalgae: The role of eutrophication

“…Our results confirm that the picocyanobacteria are able to change constituents of produced allelopathic compounds under different availability of nutrients; however, information on which metabolites mediate allelopathic interactions is still insufficient (Leão et al, ). The allelopathic activity of Baltic Synechococcus strains was detected only recently (Barreiro Felpeto et al, ; Śliwińska‐Wilczewska et al, , ) therefore, identification and isolation of the compounds responsible for the observed effect will require further research.…”

“…After the addition of cell-free filtrate, the highest decline in P m was observed for S. marinoi (Figure 3 and filtrate had no allelopathic effects on the growth of O. submarina. Some authors also showed that cyanobacteria have a negative effect on green algae, diatoms, and other cyanobacteria (e.g., Bittencourt-Oliveira et al, 2014;Ma et al, 2015;Śliwińska-Wilczewska et al, 2016;Wang et al, 2017;Żak, Musiewicz, & Kosakowska, 2012). Allelopathy affects phytoplankton succession and competition because it gives a competitive advantage to the allelopathic species and/or the resistant targets organisms (Granéli & Hansen, 2006).…”

“…Our results showed that these species are more sensitive to picocyano- Experience with the addition of the filtrate obtained from cultures of picocyanobacterium Synechococcus sp., growing in nutrientsufficient medium showed a significant inhibitory effect not only on cell number but also on the maximum PSII quantum efficiency (F v /F m ) and photosynthetic capacity (P m ) of analyzed microalgae. In a few previous works, it was also shown that allelochemicals may affect the chlorophyll a fluorescence and photosynthesis performance of target organisms (e.g., Barreiro Felpeto et al, 2018;Ma et al, 2015;Prince, Myers, & Kubanek, 2008;Śliwińska-Wilczewska et al, 2016;Song et al, 2017). In this study, it was found that the value of F v /F m of B.…”

“…Target organisms may be completely eliminated, inhibited, resistant to the allelochemicals, or be stimulated (e.g., Barreiro et al, 2017;Brutemark, Vandelannoote, Engström-Öst, & Suikkanen, 2015;Dias et al, 2017;Pichierri et al, 2017;Śliwińska-Wilczewska et al, 2017). However, as picocyanobacterial allelopathy is a relatively new topic of research in aquatic ecosystems, fewer studies, and information exist (Barreiro Felpeto, Śliwińska-Wilczewska, Złoch, & Vasconcelos, 2018;Costa et al, 2015;Śliwińska-Wilczewska et al, 2017;Śliwińska-Wilczewska, Pniewski, & Latała, 2016). Therefore, it is essential to characterize allelopathic activity of picocyanobacteria under different experimental conditions and their impact on target organisms.…”