Cyanobacterial Allelochemicals But Not Cyanobacterial Cells Markedly Reduce Microbial Community Diversity

Abstract

The freshwater cyanobacterium Phormidium sp. LEGE 05292 produces allelochemicals, including the cyclic depsipeptides portoamides, that influence the growth of heterotrophic bacteria, cyanobacteria, and eukaryotic algae. Using 16S rRNA gene amplicon metagenomics, we show here that, under laboratory conditions, the mixture of metabolites exuded by Phormidium sp. LEGE 05292 markedly reduces the diversity of a natural planktonic microbial community. Exposure of the same community to the portoamides alone resulted in a similar outcome. In both cases, after 16 days, alpha-diversity estimates for the allelochemical-exposed communities were less than half of those for the control communities. Photosynthetic organisms, but also different heterotrophic-bacteria taxa were found to be negatively impacted by the allelochemicals. Intriguingly, when Phormidium sp. LEGE 05292 was co-cultured with the microbial community, the latter remained stable and closer to non-exposed than to allelochemical-exposed communities. Overall, our observations indicate that although under optimal growth conditions Phormidium sp. LEGE 05292 is able to synthesize potent allelochemicals that severely impact different microorganisms, its allelopathic effect is not pronounced when in contact with a complex microbial community. Therefore, under ecologically relevant conditions, the allelopathic behavior of this cyanobacterium may be regulated by nutrient availability or by interactions with the surrounding microbiota.

Drivers and ecological consequences of dominance in periurban phytoplankton communities using networks approaches

“…Another hypothesis might be related to the effect of competition/exclusion mechanisms on community composition (Aguilera et al, 2017a;Dokulil and Teubner, 2000;Litchman, 2003). For instance, Cyanobacteria are more efficient than other groups for light-harvesting in low-light conditions generated by high biomass (Litchman, 2003;Schwaderer et al, 2011) and are able to release a wide variety of allelochemical compounds (Dias et al, 2017;Holland and Kinnear, 2013;Leflaive and Ten-Hage, 2007). To conclude, it ap pears that the ecological particularities of this group allow their dominance in waterbodies under anthropogenic pressure, and this resulted in enhanced community functioning through selection effect.…”

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

“…However, in this study, the greatest allelopathic effect was observed for picocyanobacterium growing in a nutrient‐sufficient culture medium. Other authors also observed that some cyanobacteria can cause allelopathy under non‐limiting nutrient conditions (Allen et al, ; Bittencourt‐Oliveira et al, ; Brutemark et al, ; Dias et al, ; Leflaive & Ten‐Hage, ). Allen et al () showed that allelopathic compounds produced by green algae Uronema confervicolum were the highest in the treatment with the highest nutrient level and were much lower in the unbalanced nutrients treatments.…”

“…It has been also proposed that changes in the plankton community structure are caused by the differential effect of allelochemicals on different species (Mulderij, Van Donk, & Roelofs, 2003). 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).…”

Urbanization and Waterborne Pathogen Emergence in Low-Income Countries: Where and How to Conduct Surveys?

“…The antibacterial activity of two Ludwigia species (invasive aquatic weeds) against a series of bacteria, including pathogens, has been demonstrated [58]. The production of antibiotics as allelochemicals by phytoplankton and cyanobacteria has also been documented [59][60][61][62][63]. However, antibiotic-induced interactions among marine microorganisms have mostly been highlighted within marine biofilms [64].…”