Chlorophyll a synthesis by an animal using transferred algal nuclear genes
- 449 Downloads
Chlorophyll synthesis is an ongoing requirement for photosynthesis and a ubiquitous, diagnostic characteristic of plants and algae amongst eukaryotes. However, we have discovered that chlorophyll a (Chla) is synthesized in the symbiotic chloroplasts of the sea slug, Elysia chlorotica, for at least 6 months after the slugs have been deprived of the algal source of the plastids, Vaucheria litorea. In addition, using transcriptome analysis and PCR with genomic DNA, we found 4 expressed genes for nuclear-encoded enzymes of the Chla synthesis pathway that have been horizontally transferred from the alga to the genomic DNA of the sea slug. These findings demonstrate the first discovery of Chla production in an animal using transferred nuclear genes from its algal food.
KeywordsHorizontal gene transfer chlorophyll synthesis chloroplast symbiosis kleptoplasty Elysia chlorotica Vaucheria litorea
Unable to display preview. Download preview PDF.
- Graves, D.A., Gibson, M.A., and Bleakney, J.S. 1979. The digestive diverticula of Alderia modesta and Elysia chlorotica (Opisthobranchia : Sacoglossa). Veliger 21: 415–422.Google Scholar
- Green, B.J., Li, W.-Y., Manhart, J.R., Fox, T.C., Summer, E.J., Kennedy, R.A., Pierce, S.K., and Rumpho, M.E. 2000. Molluscalgal chloroplast endosymbiosis, photosynthesis, thylakoid protein maintenance, and chloroplast gene expression continue for many months in the absence of the algal nucleus. Plant Physiology 124: 331–342.CrossRefPubMedGoogle Scholar
- Hanten, J.J. and Pierce, S.K. 2001. Synthesis of several lightharvesting complex I polypeptides is blocked by cycloheximide in symbiotic chloroplasts in the sea slug, Elysia chlorotica (Gould): A case for horizontal gene transfer between alga and animal? Biological Bulletin 201: 33–44.CrossRefGoogle Scholar
- Mondy, W.L. and Pierce, S.K. 2003. Apoptotic-like morphology is associated with the annual synchronized death of a population of kleptoplastic sea slugs (Elysia chlorotica). Journal of Invertebrate Biology 122: 126–137.Google Scholar
- Owen, G. 1966. Digestion. In: Physiology of Mollusca II. Wilbur, K.M. and Yonge, C.M., eds. Academic Press, NY, pp. 53–96.Google Scholar
- Pierce, S.K., Curtis, N.E., Hanten, J.J., Boerner, S.L., and Schwartz, J.A. 2007. Transfer, integration and expression of functional nuclear genes between multicellular species. Symbiosis 43: 57–64.Google Scholar
- Pierce, S.K., Curtis, N.E., Massey, S.E., Bass, A.L., Karl, S.A., and Finney, C. 2006. A morphological and molecular comparison between Elysia crispata and a new species of kleptoplastic sacoglossan sea slug (Gastropoda: Opisthobranchia) from the Florida Keys USA. Molluscan Research 26: 23–38.Google Scholar
- Rumpho, M.E., Worful, J.M., Lee, J., Kannan, K., Tyler, M.S., Bhattacharya, D., Moustafa, A., and Manhart, J.R. 2008. Horizontal gene transfer of the algal nuclear gene psbO to the photosynthetic sea slug Elysia chlorotica. Proceedings of the National Academy of Science, USA 105: 17867–17871.CrossRefGoogle Scholar
- Schwartz, J.A., Curtis, N.E., and Pierce, S.K. Transcriptome analysis reveals several horizontally transferred algal nuclear genes in the genome of the sea slug Elysia chlorotica. Journal of Molecular Evolution (submitted).Google Scholar
- Wamsley, J. and Adamson, H. 1994. Chlorophyll turnover in etiolated greening barley transferred to darkness: Isotopic (1-14C glutamic acid) evidence of dark chlorophyll synthesis in the absence of chlorophyll accumulation. Physiologia Plantarum 93: 435–444.Google Scholar
- West, H.H., Harrigan, J., and Pierce, S.K. 1984. Hybridization of two populations of a marine opisthobranch with different developmental patterns. Veliger 26: 199–206.Google Scholar