AB 4:15-21 (2008) - doi:10.3354/ab00092
Kleptoplasts mediate nitrogen acquisition in the sea slug Elysia viridis
Bart Teugels1,*, Steven Bouillon2,3,4,*,**, Bart Veuger3, Jack J. Middelburg3, Nico Koedam1
**Corresponding author. Email: firstname.lastname@example.org
ABSTRACT: Kleptoplasty is a remarkable form of symbiosis whereby photosynthetically functional algal chloroplasts are retained by the host organism. Certain sacoglossan sea slugs form such associations and some species such as Elysia viridis (Montagu, 1804) can survive for months without access to their food algae. We report evidence for light-dependent assimilation of ammonium, nitrite, and urea (but not nitrate) in E. viridis with functional kleptoplasts. N uptake was decreased in slugs with reduced chloroplast densities, and after exposure to inhibitors of glutamine synthetase and glutamate synthetase. Incorporation of 15N-labeled substrates was traced into individual hydrolyzable amino acids, with highest incorporation in glutamine-glutamate. N assimilation by kleptoplasts in multicellular hosts constitutes an additional mechanism which may contribute to the unique and long-lived functionality of these symbioses.
KEY WORDS: Kleptoplasty · Nitrogen assimilation · Sacoglossan · Elysia viridis
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