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Symbioses between eukaryotes and nitrogen-fixing cyanobacteria off Brazil

Symbioses between eukaryotes and nitrogen-fixing cyanobacteria off Brazil

Seminar at the Pontifical University of Chile in Santiago and the Universidad de Concepcion (ECODIM mini symposium).
Based on our paper in ISME: https://www.nature.com/articles/s41396-018-0050-z

Daniel Vaulot

April 06, 2018

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  1. Catherine Ribeiro, Adriana Lopes dos Santos, Dominique, Marie, Frederico Brandini,

    Daniel Vaulot Station Biologique de Roscoff, UPMC et CNRS, France Universidade de São Paulo, Brasil Symbiosis between nitrogen-fixing bacteria and eukaryotes on the continental shelf of Brazil
  2. 16S rRNA from sorted cells Chrysophyc Clade B2 Isochrysidales Braarudosphaeraceae

    EF051761 - Chrysochromulina campanulifera - strain UIO J10 HM133350 - Biosope T60 16S OXY107.017 HM133259 - Biosope T41 16S PLA491.033 LK391826 - Ochromonas sp. - strain F933 HM133175 - Biosope T35 16S PLA491.033 St.98 surf PEUK clone F4 St.TRICHO surf PEUK clone B1 St.98 surf NEUK clone C2 HM133499 - Biosope T84 16S PLA491.026 HM133324 - Biosope T58 16S PLA491.010 LN735407 - Emiliania huxleyi - strain RCC 2941 KP282836 - Gephyrocapsa muellerae - strain RCC3862 LK391825 - Chrysochromulina apheles - strain F929 St.98 surf PEUK clone E5 HM133343 - Biosope T60 16S OXY107.004 HM133380 - Biosope T60 16S PLA491.021 HM133420 - Biosope T65 16S.38a AB847984 - Braarudosphaera bigelowii - strain TMRscBb1 2 2 7 15 picoplankton sequences nanoplankton sequences 69 100 99 57 88 92 99 90 100
  3. Strategy • Samples preserved with DMSO 10% • Two fractions

    sorted by flow cytometry : Pico and Nano (56 samples) • Two genes – nuclear 18S rRNA (V4) – nifH • 1 run Ilumina MiSeq 2*250 bp • Analysis with Mothur • Assignement : PR2, BLAST
  4. Bray distance clustering based on major 18S OTUs Dinos Mam

    Prym Diatoms Chrys UCYN-A1 host Ostreo + Bathy Prymnesiophyceae Prorocentrum
  5. Conclusion On the shelf off Brazil • Two major types

    photosynthetic eukaryotic communities : – Braarudosphaeraceae – Ostreococcus + Bathycoccus • Nitrogen fixers – UCYN-A is dominant nitrogen fixer : A1, A2, A3, A4 • Network analysis – Recover A1 and A2 associations – A4 could have same host than A2 (Braarudosphaera) – A3 ?