Nitrogen control of chloroplast development and differentiation. Annual progress report

Technical Report · Sun Dec 01 00:00:00 EST 1991

DOI:https://doi.org/10.2172/10161069· OSTI ID:10161069

Schmidt, G W

The growth and development of plants and photosynthetic microorganisms is commonly limited by the availability of nitrogen. Our work concerns understanding the mechanisms by which plants and algae that are subjected to nitrogen deprivation alter the composition of photosynthetic membranes and enzymes involved in photosynthetic carbon metabolism. Toward these ends, we study biosynthetic and gene expression processes in the unicellular green alga Chlamydomonas reinhardtii which is grown in an ammonium-limited continuous culture system. We have found that the expression of nuclear genes, including those encoding for light-harvesting proteins, are severely repressed in nitrogen-limited cells whereas, in general, chloroplast protein synthesis is attenuated primarily at the level of mRNA translation. Conversely, nitrogen deprivation appears to lead to enhanced synthesis of enzymes that are involved in starch and storage lipid deposition. In addition, as a possible means by which photosynthetic electron transport activities and ATP synthesis is sustained during chronic periods of nitrogen deprivation, thylakoid membranes become enriched with components for chlororespiration. Characterization of the chlororespiratory electron transport constituents, including cytochrome complexes and NAD(P)H dehydrogenase is a major current effort. Also, we are striving to isolate the genes encoding chlororespiration proteins toward determining how they and others that are strongly responsive to nutrient availability are regulated.

• Research Organization: Georgia Univ., Athens, GA (United States). Research Foundation
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG09-84ER13188
• OSTI ID: 10161069
• Report Number(s): DOE/ER/13188-7; ON: DE92017392
• Resource Relation: Other Information: PBD: Dec 1991
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
59 BASIC BIOLOGICAL SCIENCES
CHLOROPLASTS
MOLECULAR BIOLOGY
NUCLEOTIDE DEHYDROGENASES
FRACTIONATION
CHLOROPHYLL-BINDING PROTEINS
GENE REGULATION
PROGRESS REPORT
BIOLOGICAL PATHWAYS
NUTRITIONAL DEFICIENCY
CHLAMYDOMONAS
CYTOCHROMES
140505
550200
PHOTOCHEMICAL, PHOTOBIOLOGICAL, AND THERMOCHEMICAL CONVERSION
BIOCHEMISTRY