Allelopathic activity of the picocyanobacterium Synechococcus sp. on unicellular eukaryote planktonic microalgae

Abstract

The production and release of allelopathic compounds is an important adaptation by which some species of cyanobacteria can achieve a competitive advantage over other primary producers. In the present study we tested the allelopathic activity of the picocyanobacterium Synechococcus sp. against the following coexisting unicellular eukaryote microalgae: Porphyridium purpureum, Stichococcus bacillaris, Prymnesium parvum and Nitzschia dissipata. With these species, we covered a wide range of taxonomic groups. We demonstrated that both the addition of Synechococcus sp. cell-free filtrate and coculture inhibited the growth, chlorophyll content and photosynthetic rate of P. purpureum and S. bacillaris. Conversely, P. parvum, a well-known mixotroph, was positively affected by both Synechococcus sp. treatments. In contrast, N. dissipata was not affected by either the picocyanobacterial filtrate or coculture. These results suggest that the negative allelopathic effect is related to a reduction in the photosynthetic rate, and that Synechococcus sp. allelopathy should be taken into account in the interactions between picocyanobacteria and eukaryote competitors coexisting in a planktonic system.

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

“…The filtrate from Synechococcus sp. also decreased the fluorescence parameter of P. purpureum and Stichococcus bacillaris, but increased the F v /F m of P. parvum [18]. Experiments conducted on freshwater species by Kovacs et al [27] showed a significant decrease in the F v /F m of green alga Scenedesmus quadricauda after the addition of coexisting freshwater picocyanobacteria Cyanobium gracile and Cylindrospermopsis raciborskii.…”

“…and Phormidium sp. [16], bloom-forming cyanobacteria Nodularia spumigena [17], and Porphyridium purpureum and Prymnesium parvum [18]. Dominance by certain phytoplankton species in the community can be explained by the inhibition caused in the growth of co-existing species.…”

The Importance of Allelopathic Picocyanobacterium Synechococcus sp. on the Abundance, Biomass Formation, and Structure of Phytoplankton Assemblages in Three Freshwater Lakes

“…filtrate strongly inhibited the growth of Skeletonema marinoi Sarno and Zingone. In contrast,Śliwińska-Wilczewska et al [22] showed that Nitzschia dissipata (Kützing) Rabenhorst was not affected by the picocyanobacterial filtrate or co-culture. It was also found that marine Synechocystis sp.…”

“…Studies have shown that cyanobacteria can also affect the growth of some Chlorophyceae and Charophyceae species [13,[50][51][52][58][59][60][61][62][63] and picoplanktonic cyanobacteria deserved special attention here.Śliwińska-Wilczewska et al [22] demonstrated that both the addition of Synechococcus sp. cell-free filtrate and co-culture inhibited the growth of Stichococcus bacillaris Nägeli.…”

“…In this paper, Kovacs et al [17] for the first time described that the freshwater picocyanobacterium Cyanobium gracile Rippka and Cohen-Bazire has a strong negative effect on green alga Scenedesmus quadricauda (Turpin) Brébisson. Most of the work on the allelopathic activity of picoplanktonic cyanobacteria of the genus Synechococcus has been described for the strain CCBA BA-124, originating from the Baltic Sea [18][19][20][21][22][23][24][25]. Additionally, Konarzewska et al [26] showed allelopathic properties of Baltic Synechococcus sp.…”