Phenotypic and genotypic characterization of Thalassiosira pseudonana (Bacillariophyceae) strains

  • Cecilia Rad Menendez

Student thesis: Doctoral ThesisDoctor of Philosophy (awarded by OU/Aberdeen)


Over recent years, developments in genomics have greatly increased the quantity and quality of molecular data available to the scientific community and to date, the genome sequences of two “model” diatoms have been published: Thalassiosira pseudonana (Armbrust et al. 2004) and Phaeodactylum tricornutum (Bowler et al. 2008). These genomes have the potential to facilitate the use of genomic data to investigate diatom cell
processes, increasing our understanding of these organisms and their future
biotechnological applications. These developments have facilitated the genetic and phenotypic characterization of the strains of P. tricornutum available from culture collections (De Martino et al. 2007); however, a comparable study has not been performed for T. pseudonana.
In the present study a polyphasic approach has been employed to characterize ten T. pseudonana strains. The morphological characterization revealed that all the strains investigated were virtually identical, apart from T. pseudonana CS-20, which seemed to have a more weakly silicified frustule and variation in the rimoportulae position. From a biochemical perspective, based on fatty acid profiles, all the strains shared the same fatty acid composition, although variation in production was observed. Genotypic characterization based on DNA barcode genes revealed that the strains were identical; however, Amplified Fragment Length Polymorphism (AFLP) analyses indicated that the axenic strains belonged to three different clusters. Although the population variability
obtained was low, it was enough to group the strains according to their biogeography.
These findings will help to characterize the strains of this model organism available to researchers worldwide through culture collections. At the same time it provides valuable information about microbial populations, how they can be genetically distinct and how these differences could be related to their biogeography. In addition, this study revealed that an optimal cryopreservation protocol has yet to be developed for this particular species, and perhaps different protocols will be needed for different strains.
Date of Award26 Nov 2011
Original languageEnglish
Awarding Institution
  • University of Edinburgh
SponsorsIndustrial Biotechnology Innovation Centre & Highlands and Islands Enterprise
SupervisorMichele Stanley (Supervisor), John Day (Supervisor), Gordon Mcdougall (Supervisor) & Tim Atack (Supervisor)

Cite this