An uncultured marine cyanophage encodes an active phycobilisome proteolysis adaptor protein NblA

Omer Nadel, Andrey Rozenberg, José Flores-Uribe, Shirley Larom, Rakefet Schwarz, Oded Béjà

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Phycobilisomes (PBS) are large water-soluble membrane-associated complexes in cyanobacteria and some chloroplasts that serve as light-harvesting antennae for the photosynthetic apparatus. When deplete of nitrogen or sulphur, cyanobacteria readily degrade their phycobilisomes allowing the cell to replenish these vanishing nutrients. The key regulator in the degradation process is NblA, a small protein (∼6 kDa), which recruits proteases to the PBS. It was discovered previously that not only do cyanobacteria possess nblA genes but also that they are encoded by genomes of some freshwater cyanophages. A recent study, using assemblies from oceanic metagenomes, revealed genomes of a novel uncultured marine cyanophage lineage, representatives of which contain genes coding for the PBS degradation protein. Here, we examined the functionality of nblA-like genes from these marine cyanophages by testing them in a freshwater model cyanobacterial nblA knockout. One of the viral NblA variants could complement the non-bleaching phenotype and restore PBS degradation. Our findings reveal a functional NblA from a novel marine cyanophage lineage. Furthermore, we shed new light on the distribution of nblA genes in cyanobacteria and cyanophages.

Original languageEnglish
Pages (from-to)848-854
Number of pages7
JournalEnvironmental Microbiology Reports
Issue number6
StatePublished - 1 Dec 2019

Bibliographical note

Publisher Copyright:
© 2019 Society for Applied Microbiology and John Wiley & Sons Ltd


We thank Faris Salama for help with the spectroscopic measurements, and Laurence Garczarek and Noam Adir for helpful discussions. This work was funded by a European Commission ERC Advanced Grant (no. 321647), Israel Science Foundation grant (143/18) and the Louis and Lyra Richmond Memorial Chair in Life Sciences (to O.B.).

FundersFunder number
European Commission ERC Advanced321647
Israel Science Foundation143/18


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