Toxic and non-toxic dinoflagellates host distinct bacterial communities in their phycospheres

Abstract Dinoflagellates encompass highly abundant and diverse toxin-producing species among marine phytoplankton. Previous works suggested that some bacterial taxa may affect toxins production in dinoflagellates, however, little is known about impact of toxic dinoflagellates on their co-existing flora. Here we characterized the communities associated with 22 clonal cultures using DNA metabarcoding method, including 11 confirmed have not been reported to be toxic. Beta diversity analysis revealed all group were clustered together distinctly separated from non-toxic group, strongly suggesting community composition was largely influenced by dinoflagellate hosts. The found include higher relative abundance non-carbohydrate utilizers xenobiotic-degrading showed inhibitory effects algicidal bacteria. These findings host distinctive multiple ways phycospheres.