Research

DNA fingerprinting differentiation between β-carotene hyperproducer strains of Dunaliella from around the world

Jorge Olmos^1,2 , Leonel Ochoa^1,2 , Jesus Paniagua-Michel^1,2 and Rosalía Contreras^1,2

¹  Molecular Microbiology Laboratory, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Department of Marine Biotechnology, Ensenada, B.C, México

²  Biotecnología Marina, PO Box 430222, San Diego, California, 92143-0222, USA

author email corresponding author email

Saline Systems 2009, 5:5doi:10.1186/1746-1448-5-5

Published:	30 June 2009

Abstract

Background

Dunaliella salina is the most important species of the genus for β-carotene production. Several investigations have demonstrated that D. salina produces more than 10% dry weight of pigment and that the species grows in salt saturated lagoons. High plasticity in the green stage and the almost indistinguishable differences in the red phase make identification and differentiation of species and ecotypes very difficult and time consuming.

Results

In this work, we applied our intron-sizing method to compare the 18S rDNA fingerprint between D. salina (CCAP 19/18), D. salina/bardawil (UTEX LB2538) and β-carotene hyperproducing strains of Dunaliella isolated from salt saturated lagoons in Baja, Mexico. All hyperproducer strains reached β-carotene levels of about 10 pg/cell. Optical microscopy did not allow to differentiate between these Dunaliella strains; however, 18S rDNA fingerprinting methodology allowed us to differentiate D. salina from D. salina/bardawil.

Conclusion

In Baja Mexico we found D. salina and D. salina/bardawil species by using intron-sizing-method. The National Center for Biotechnology Information (NCBI) Dunaliella 18S rDNA gene sequences were analyzed with our methodology and extraordinary correlation was found with experimental results.