Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increase frequency and spatial distribution in temperate coastal regions including the Mediterranean Sea. O. cf. ovata outbreaks are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins. In the last years, among the ecological factors that trigger or regulate the algal bloom dynamics, bacteria-microalgae interactions have received increasingly attention. This study investigated the microbial dynamics and the phylogenetic structure of the bacterial community co-occurring with Ostreopsis cf. ovata in batch cultures during different algal growth phases. Cultures of a O. cf. ovata strain isolated along the NW Adriatic Sea were maintained under controlled conditions for a period of 42 days. O. cf. ovata, bacterial cell abundances were monitored along with removal of major nutrients from the medium. Phylogenetic composition of bacterial community was assessed by next generation sequencing of bacterial 16S rDNA hypervariable regions. Bacterial growth showed two different exponential steps, the first step occurring in parallel with the algal exponential phase and the second one in concomitance with the algal mid-stationary phase. Ion torrent data revealed the presence of 12 bacterial phyla, 17 classes and 150 genera all along the experiment. A self-sufficient consortium for vitamin synthesis composed by only few genera belonging to Alphaproteobacteria (65-96%) and Sphingobacteria (2-34%) dominated the community. Our results allow to postulate on specific mutualistic and antagonistic interactions between O. cf. ovata and the associated microbial community in batch cultures, which ultimately will affect algal cellular physiology and potentially toxin dynamics. Moreover, the data pave the way for further investigations on relationships between bacteria-O. cf. ovata interactions and vitamins availability in the environment.
Preliminary results on phylogenetic structure of the bacterial community associated with Ostreopsis cf. ovata in batch cultures / Vanucci, S.; Guidi, F.; Pistocchi, R. - STAMPA. - (2015), pp. 3-3. (Intervento presentato al convegno Riunione scientifica annuale del Gruppo di Lavoro per l’Algologia della Società Botanica Italiana tenutosi a Venezia nel 6-7 novembre 2015).
Preliminary results on phylogenetic structure of the bacterial community associated with Ostreopsis cf. ovata in batch cultures.
GUIDI, FLAVIO;PISTOCCHI, ROSSELLA
2015
Abstract
Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increase frequency and spatial distribution in temperate coastal regions including the Mediterranean Sea. O. cf. ovata outbreaks are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins. In the last years, among the ecological factors that trigger or regulate the algal bloom dynamics, bacteria-microalgae interactions have received increasingly attention. This study investigated the microbial dynamics and the phylogenetic structure of the bacterial community co-occurring with Ostreopsis cf. ovata in batch cultures during different algal growth phases. Cultures of a O. cf. ovata strain isolated along the NW Adriatic Sea were maintained under controlled conditions for a period of 42 days. O. cf. ovata, bacterial cell abundances were monitored along with removal of major nutrients from the medium. Phylogenetic composition of bacterial community was assessed by next generation sequencing of bacterial 16S rDNA hypervariable regions. Bacterial growth showed two different exponential steps, the first step occurring in parallel with the algal exponential phase and the second one in concomitance with the algal mid-stationary phase. Ion torrent data revealed the presence of 12 bacterial phyla, 17 classes and 150 genera all along the experiment. A self-sufficient consortium for vitamin synthesis composed by only few genera belonging to Alphaproteobacteria (65-96%) and Sphingobacteria (2-34%) dominated the community. Our results allow to postulate on specific mutualistic and antagonistic interactions between O. cf. ovata and the associated microbial community in batch cultures, which ultimately will affect algal cellular physiology and potentially toxin dynamics. Moreover, the data pave the way for further investigations on relationships between bacteria-O. cf. ovata interactions and vitamins availability in the environment.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
