Post Doc

Marie Curie Postdoctoral scholar

Francisco M. Cornejo-Castillo

Main Scientific interests

My main research interest is to bring single-celled symbioses (i.e., symbiosis between unicellular organisms) to a higher level of understanding by providing knowledge on their ecological and evolutionary patterns. Symbiotic interactions are key drivers of ecological diversification and evolutionary innovation on Earth. For example, one of the major innovations in nature was postulated in the Theory of Endosymbiosis by Linn Margulis, which posits that plastids and mitochondria in eukaryotes originated from bacterial endosymbionts. However, the underlying processes remain difficult to address because they occur over geological time scales. Thus, the study of present-day symbiotic associations between unicellular eukaryotes and prokaryotes might be an alternative way to understand how symbioses are established. Therefore, on of the main objectives of my research is to gain knowledge into the ecology and the evolution of the single cell nitrogen-fixing symbiosis to, eventually, get a better understanding of the mechanisms conducting to the plastid formation.


During my career, I have progressively moved from a wide assessment of the diversity and ecology of marine nitrogen fixers in the ocean through metagenomics/metatranscriptomics and microscopy approaches, towards a more deep exploration of the evolutionary processes behind the interaction between nitrogen-fixing cyanobacteria and eukaryotes in the ocean, by means of single-cell based approaches.

Previous and current positions

2020 to present - Marie Curie fellowship (return phase) at the Station Biologique de Roscoff (France) for the continuation of the project UCYN2PLAST.

2020 (10 months) - Postdoctoral scholar at the Ocean Science Department, University of California, Santa Cruz (UCSC), Santa Cruz, California (USA).

2018/2019 (2 years) - Marie Curie fellowship (outgoing phase) at the Ocean Science Department, University of California, Santa Cruz (UCSC), Santa Cruz, California (USA) for the project UCYN2PLAST: ‘Exploring the mechanisms underlying the evolution of plastids through the study of an unusual N2-fixing symbiosis’.

2017 (7 months) - Research position at the AZTI FUNDAZIOA, Basque Country (Spain) for the project MAROMEGA: ‘New alternatives for the omega-3 production from natural resources’.

2016 (6 months) - Specialist technician at the Universitat Autònoma de Barcelona (UAB), Barcelona (Spain) for the project: ‘Metagenomic insights in nitrogen fixation in the Red Sea’.

2015 (5 months) - Research assistant at the Institut de Ciències del Mar (ICM-CSIC), Barcelona (Spain) for the project: ‘Microbial diversity in marine ecosystems’.

2013/2014 (8 months) - Research position at the Institut de Ciències del Mar (ICM-CSIC), Barcelona (Spain) for the project: ‘Marine microbial pangenomes: from the genome sequencing of uncultured taxa to population genetics’.

2009/2013 (4 years) - FPI Research fellowship at Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain.

2008/2009 (9 months) - Research assistant at the Institute of Aquaculture, University of Santiago de Compostela (Spain) for the project: ‘Characterization of mobile DNA elements in Photobacterium damselae (AQUAGENOMICS-2)’.


2017 - PhD Marine Sciences (excellent, cum laude) - Institute of Marine Sciences (ICM, Barcelona, Spain) and Polytechnic University of Catalonia (Barcelona, Spain)

2011 - M.S. Oceanography - University of Las Palmas de Gran Canaria (Spain)

2008 - B.S. Biological Sciences - University of Seville and University of Santiago de Compostela (Spain)



Cornejo-Castillo, F. M. & Zehr, J.P. (2020) Intriguing size distribution of the uncultured and globally widespread marine non-cyanobacterial diazotroph Gamma-A. The ISME Journal, DOI: 10.1038/s41396-020-00765-1

Cornejo-Castillo, F. M. & Zehr, J.P. (2019) Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean. PNAS, DOI:10.1073/pnas.1908165116. IF: 9.41.

Huber, P., Cornejo-Castillo, F.M., Ferrera, I., Sánchez, P., Logares, R., Metz, S., Llames, M.E., Acinas, S.G., Gasol, J.M., Unrein, F. (2019) Primer design for an accurate view of picocyanobacterial community structure by using high-throughput sequencing. Applied and Environmental Microbiology, DOI: 10.1128/AEM.02659-18.

Cornejo-Castillo, F.M., Muñoz-Marín, M. d. C., Turk-Kubo, K., Royo-Llonch, M., Farnelid, H., Acinas, S.G., Zehr, J.P. UCYN-A3, a newly characterized open ocean sublineage of the symbiotic N2-fixing cyanobacterium Candidatus Atelocyanobacterium thalassa. (2019) Environmental Microbiology 21 (1), 111-124.

Fridman, S., Flores-Uribe, J., Larom, S., Alalouf, O., Liran, O., Yacoby, I., Salama, F., Bailleul, B., Rappaport, F., Ziv, T., Sharon, I., Cornejo-Castillo, F.M., Philosof, A., Dupont, C.L., Sánchez, P., Acinas, S.G., Rohwer, F.L., Lindell, D., Béjà, O. (2017). A myovirus encoding both photosystem i and II proteins enhances cyclic electron flow in infected Prochlorococcus cells. Nature Microbiology. 8(JUL),1317.

Alberti, A., Poulain, J., Engelen, S., Labadie, K., Romac, S., Ferrera, I., Albini, G., Aury, J.-M., Belser, C., Bertrand, A., Cruaud, C., Da Silva, C., Dossat, C., Gavory, F., Gas, S., Guy, J., Haquelle, M., Jacoby, E., Jaillon, O., Lemainque, A., Pelletier, E., Samson, G., Wessner, M., Acinas, S.G., Royo-Llonch, M., Cornejo-Castillo, F.M., et al. (2017). Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition. Scientific Data. 4,170093.

Royo-Llonch, M.,Ferrera, I., Cornejo-Castillo, F.M., Sánchez, P., Salazar, G., Stepanauskas, R., González, J.M., Sieracki, M.E., Speich, S., Stemmann, L., Pedrós-Alió, C., Acinas, S.G.  (2017). Exploring microdiversity in novel Kordia sp. (Bacteroidetes) with proteorhodopsin from the tropical Indian Ocean via Single Amplified Genomes. Frontiers in Microbiology. 8(JUL),1317.

Farrant, G., K., Doré, H., Cornejo-Castillo, F. M., Partensky, F., Ratin, M., Ostrowski, M., Pitt F. D., Wincker, P., J. Scanlan, D. J., Iudicone, D., Acinas, S. G., Garczarek, L. (2016). Delineating ecologically significant taxonomic units from global patterns of marine picocyanobacteria. PNAS, DOI: 10.1073/pnas.1524865113.

Cornejo-Castillo, F.M., Cabello, A.M., Salazar, G., Sánchez-Baracaldo, P., Lima-Mendez, G., Hingamp, P., Alberti, A., Sunagawa, S., Bork, P., de Vargas, C., Raes, J., Bowler, C., Wincker, P., Zehr, J.P., Gasol, J.M., Massana, R., Acinas, S.G. (2016). Cyanobacterial symbionts diverged in the late Cretaceous towards lineage-specific nitrogen fixation factories in single-celled phytoplankton. Nature Communications, DOI:10.1038/ncomms11071.

Salazar, G., Cornejo-Castillo, F.M., Borrull, E., Díez-Vives, C., Lara, E., Vaqué, D., Arrieta, J.M., Duarte, C.M., Gasol, J.M., Acinas, S.G. (2015). Particle-association lifestyle is a phylogenetically conserved trait in bathypelagic prokaryotes. Molecular Ecology, DOI:10.1111/mec.13419.

Cabello, A.M., Cornejo-Castillo, F.M., Raho, N., Blasco, D., Vidal, M., Audic, S., de Vargas, C., Latasa, M., Acinas, S.G., Massana, R. (2015). Global distribution and vertical patterns of a prymnesiophyte–cyanobacteria obligate symbiosis. The ISME Journal, DOI:10.1038/ismej.2015.147.

Salazar, G., Cornejo-Castillo, F.M., Benítez-Barrios, V., Fraile-Nuez, E., Álvarez-Salgado, X.A., Duarte, C.M., Gasol, J.M., Acinas, S.G. (2015). Global diversity and biogeography of deep-sea pelagic prokaryotes. The ISME Journal, DOI:10.1038/ismej.2015.137.

Sunagawa, S., Coelho, L.P., Chaffron, S., Kultima, J.R., Labadie, K., Salazar, G., Djahanschiri, B., Zeller, G., Mende, D.R., Alberti, A., Cornejo-Castillo, F.M., et al. (2015). Structure and function of the global ocean microbiome. Science, DOI:10.1126/science.1261359.

Lima-Mendez, G., Faust, K., Henry, N., Decelle, J., Colin, S., Carcillo, F., Chaffron, S., Ignacio-Espinosa, J.C., Roux, S., Vincent, F., Bittner, L., Darzi,Y., Wang, J., Audic, S., Berline, L., Bontempi, G., Cabello, A.M., Coppola, L., Cornejo-Castillo, F.M., et al. (2015). Determinants of community structure in the global plankton interactome. Science, DOI:10.1126/science.1262073.

Roitman, S., Flores-Uribe, J., Philosof, A., Knowles, B., Rohwer, F., Ignacio‐Espinoza, J.C., Sullivan, M.B., Cornejo-Castillo, F.M., Sánchez, P., Acinas S.G., Dupont, C.L., Béjà O. (2015). Closing the gaps on the viral photosystem-I psaDCAB gene organization. Environmental Microbiology, DOI:10.1111/1462-2920.13036.

Lara, E., Holmfeldt, K., Solonenko, N., Sà, E.L., Ignacio-Espinoza, J.C., Cornejo-Castillo, F.M., Verberkmoes, N.C., Vaqué, D., Sullivan, M.B., Acinas, S.G. (2015). Life-style and genome structure of marine Pseudoalteromonas siphovirus B8b isolated from the northwestern Mediterranean Sea. PLoS ONE, DOI:10.1371/journal.pone.0114829.

Teira, E., Hernando-Morales, V., Cornejo-Castillo, F.M., Alonso-Sáez, L., Sarmento, H., Valencia-Vila, J., Catalá, T.S., Hernández-Ruiz, M., Varela, M.M., Ferrera, I., Gutiérrez Morán, X.A., Gasol, J.M. (2015). Sample dilution and bacterial community composition influence empirical leucine-to-carbon conversion factors in surface waters of the world's oceans. Applied and Environmental Microbiology, DOI:10.1128/AEM.02454-15.

Acinas, S. G., Ferrera, I., Sarmento, H., Díez-Vives, C., Forn, I., Ruiz-González, C., Cornejo-Castillo, F. M., Salazar, G. and Gasol, J. M. (2015). Validation of a new catalysed reporter deposition–fluorescence in situ hybridization probe for the accurate quantification of marine Bacteroidetes populations. Environmental Microbiology, DOI: 10.1111/1462-2920.12517. IF: 6.20.

Logares, R., Sunagawa, S., Salazar, G., Cornejo-Castillo, F.M., Ferrera, I., Sarmento, H. et al. (2013). Metagenomic 16S rDNA Illumina tags are a powerful alternative to amplicon sequencing to explore diversity and structure of microbial communities. Environmental Microbiology, DOI:10.1111/1462-2920.12250.

Karsenti, E., Acinas, S.G., et al., and the Tara Oceans Consortium*. (2011). A holistic approach to marine eco-systems biology. PLoS Biology, DOI:10.1371/journal.pbio.1001177. *Contributor as part of the Tara Oceans Consortium.