Aquatic Sciences Meeting, Albuquerque 2001

SS02 Photochemical Reactions In Surface Waters: A Major Issue in the 21st Century? (Environmental Connections)

Date: Friday, February 16, 2001, Time: 11:30:00 AM

Location: San Miguel

Parker, M, S, Marine Molecular Biotechnology Lab, University of Washington, Seattle, WA, USA, micaela@u.washington.edu

Armbrust, E, V, Marine Molecular Biotechnology Lab, University of Washington, Seattle, WA, USA, armbrust@ocean.washington.edu

EXPRESSION OF A PHOTORESPIRATORY GENE IN THE CENTRIC DIATOM THALASSIOSIRA WEISSFLOGII

Export of diatom-fixed carbon from the euphotic zone represents a major sink in the global carbon cycle. Under conditions of elevated light or O2, carbon export may be reduced due to the photorespiratory fixation of O2 and consequent release of CO2, NH3 and various dissolved organic metabolites, such as glycolate. A key enzyme of photorespiration is glycine decarboxylase (GDC). We have cloned and sequenced the cDNA corresponding to the gene for the T-protein subunit of GDC from Thalassiosira weissflogii. This represents the first component of the photorespiratory pathway that has been cloned from any marine phytoplankton and allows us to examine in more detail the conditions that govern photorespiration in diatoms. We are currently investigating the effects of rapid transitions to high light on transcription of the T-protein gene. Using competitive RT-PCR, we have shown that the T-protein gene is rapidly upregulated in cells exposed to subsaturating light after prolonged darkness. We are also examining the influence of light adaptations on T-protein message levels to determine if we can use expression of this gene as a marker for both photorespiratory potential and light history of a cell.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks