Allelopathic interactions of linoleic acid and nitric oxide increase the competitive ability of Microcystis aeruginosa

Abstract

The frequency and intensity of cyanobacterial blooms are increasing worldwide with major societal and economic costs. Interactions between toxic cyanobacteria and eukaryotic algal competitors can affect toxic bloom formation, but the exact mechanisms of interspecies interactions remain unknown. Using metabolomic and proteomic profiling of co-cultures of the toxic cyanobacterium Microcystis aeruginosa with a green alga as well as of microorganisms collected in a Microcystis spp. bloom in Lake Taihu (China), we disentangle novel interspecies allelopathic interactions. We describe an interspecies molecular network in which M. aeruginosa inhibits growth of Chlorella vulgaris, a model green algal competitor, via the release of linoleic acid. In addition, we demonstrate how M. aeruginosa takes advantage of the cell signaling compound nitric oxide produced by C. vulgaris, which stimulates a positive feedback mechanism of linoleic acid release by M. aeruginosa and its toxicity. Our high-throughput system-biology approach highlights the importance of previously unrecognized allelopathic interactions between a broadly distributed toxic cyanobacterial bloom former and one of its algal competitors.

Chemically mediated interactions between Microcystis and Planktothrix: impact on their growth, morphology and metabolic profiles

“…Disentangle when the observed growth responses are caused by allelochemicals or by the costs associated to the production of compounds is an important and critical question but would require further investigations on the nature of released compounds. Our experiment is consistent with other studies showing that exudates of Microcystis can influence the physiology of other cyanobacteria (Bartova et al ., ; Yang et al ., ; Maria et al ., ) or green algae (Bittencourt‐Oliveira et al ., ; Ma et al ., ; Dunker et al ., ; Song et al ., ; Wang et al ., ). Exposure of Microcystis strains may result in various effects on the targeted organism ranging from alteration of growth and cellular morphology, photosynthesis, changes in pigment, protein, increased formation of reactive oxygen species, activation of gene expression or cell lysis.…”

Toxicity and Disruptive Impacts of Fenhexamid Fungicide Against the Green Alga, Chlorella vulgaris.

“…After 96 h, Chlorella vulgar cells in both the control and the maximum concentration of Fenhexamid were harvest and then the sample was fixed using 2.5% glutaraldehyde at 4 o C for 12 h. The fixed cells were washed and dehydrated using a graded series of ethanol (35, 50, 70, 90 and 100%) and then embedded in epoxy resin, following the method described by Song et al (2017), then observed using a JEOL JSM 1400-plus model transmission electron microscope (TEM) and JEOL JSM 6510 model scanning electron microscope (SEM).…”

Herbicidal Activities of Some Allelochemicals and Their Synergistic Behaviors toward Amaranthus tricolor L.

“…In order to understand the allelopathic effect of combined materials and to receive a more reactive natural herbicide, binary mixtures of seven natural molecules (containing a variety of functional groups), namely R -(+)-limonene ( A ) [ 23 , 24 , 25 ], vanillin ( B ) [ 26 , 27 , 28 , 29 , 30 ], xanthoxyline ( C ) [ 11 ], vanillinic acid ( D ) [ 28 , 31 , 32 , 33 , 34 , 35 ], linoleic acid ( E ) [ 36 , 37 , 38 , 39 ], methyl linoleate ( F ) [ 40 , 41 , 42 , 43 ], and (±)-odorine ( G ) [ 12 , 13 ] ( Figure 1 ), were investigated using Chinese amaranth ( Amaranthus tricolor L.) as the test plant and Tween ® 80 as a surfactant. Chinese amaranth was chosen as a representative dicot plant because it has a high percentage of germination.…”