Poster: Secondary metabolism
Abs #
254: Revisiting classification of the carotenogenic unicellular green alga Dunaliella salina Teod. and Dunaliella bardawil
|
|
Presenter: |
Polle, Juergen EW, jpolle@brooklyn.cuny.edu | Authors | Polle, Juergen EW (A) Jin, EonSeon (B) | | Affiliations: |
(A): Department of Biology, Brooklyn College of CUNY, 2900 Bedford Ave 200NE, Brooklyn, NY 11210, USA
(B): Lab. of Plant Biotechnology, Graduate School of Bio & Infomation Technology, Hankyong National University, Ansung, Kyonggi-do, Korea
|
| Web Site: | http://146.245.216.101/biology/pages/polle/index.html | |
Microalgal species such as Dunaliella salina Teod. and Dunaliella bardawil Avron et. Ben-Amotz are used commercially to produce b-carotene. In the USA several patents protect use of D. bardawil concerning b-carotene production. If D. bardawil would not be a separate species, that would have implications for its so far restricted commercial use. Therefore, it is important to distinguish unambiguously whether both represent the same species. In a combined molecular, morphological, and physiological approach the species D. salina and D. bardawil were compared to evaluate the current classification of D. bardawil as a separate species. Phylogenetic analysis of the sequences of nuclear rDNA Internal Transcribed Spacer regions 1 and 2 (ITS1 & ITS2) in combination with a comparison of cell morphology showed that D. bardawil grouped together in the same clade with D. salina . In addition, molecular analysis of a total of 12 ITS1 and 12 ITS2 Dunaliella salina/bardawil sequences supports the current taxonomy in which there are at least two subspecies of Dunaliella salina . Subsequent analysis of the secondary structure of ITS2 revealed that, in contrast to the majority of D. salina strains investigated, D. bardawil and its three most closely related D. salina strains have a two-sided compensatory base pair change. This suggests that two different mating groups exist within the clade D. salina . Further physiological characterization of D. bardawil and of one of its most closely related D. salina strains revealed that closely related strains have different abilities to accumulate the secondary carotenoid b-carotene. Our findings show that the question of D. bardawil being a separate species cannot be settled without use of genetics.
|
|
