title: Cryptophyte farming by symbiotic ciliate host detected in situ.
abstract: Protist-alga symbiosis is widespread in the ocean, but its characteristics and function in situ remain largely unexplored. Here we report the symbiosis of the ciliate Mesodinium rubrum with cryptophyte cells during a red-tide bloom in Long Island Sound. In contrast to the current notion that Mesodinium retains cryptophyte chloroplasts or organelles, our multiapproach analyses reveal that in this bloom the endosymbiotic Teleaulax amphioxeia cells were intact and expressing genes of membrane transporters, nucleus-to-cytoplasm RNA transporters, and all major metabolic pathways. Among the most highly expressed were ammonium transporters in both organisms, indicating cooperative acquisition of ammonium as a major N nutrient, and genes for photosynthesis and cell division in the cryptophyte, showing active population proliferation of the endosymbiont. We posit this as a "Mesodinium-farming-Teleaulax" relationship, a model of protist-alga symbiosis worth further investigation by metatranscriptomic technology.
authors: Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors: Dajun
authors: D
authors: Qiu
authors: Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors: Liangmin
authors: L
authors: Huang
authors: Department of Marine Sciences, University of Connecticut, Groton, CT 06340 senjie.lin@uconn.edu.
authors: Senjie
authors: S
authors: Lin
mesh_terms: D000383:Agriculture; D064751:Ammonium Compounds / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics*; D016798:Ciliophora / Q000235:genetics* / Q000254:growth & development; D044785:Cryptophyta / Q000235:genetics* / Q000254:growth & development; D005786:Gene Expression Regulation; D057097:Harmful Algal Bloom / Q000502:physiology; D026901:Membrane Transport Proteins / Q000235:genetics; D010788:Photosynthesis / Q000235:genetics; D018087:Plastids / Q000235:genetics; D034443:RNA Transport / Q000235:genetics; D013559:Symbiosis / Q000235:genetics*
chemical_list: D064751:Ammonium Compounds; D026901:Membrane Transport Proteins
keywords: Mesodinium rubrum; cryptophyte Teleaulax; intact endosymbiont; metatranscriptome; red-tide bloom