Enhanced thermal tolerance of photosynthesis and altered chloroplast ultrastructure in a mutant of Arabidopsis deficient in lipid desaturation

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.90.3.1134· OSTI ID:7066345

Hugly, S; Kunst, L; Somerville, C ^[1]; Browse, J ^[2]

---

1. Michigan State Univ., East Lansing (USA)
2. Washington State Univ., Pullman (USA)

A mutant of Arabidopsis thaliana, deficient in activity of the chloroplast n-6 desaturase, accumulated high levels of C{sub 16:1} and C{sub 18:1} lipids and had correspondingly reduced levels of polyunsaturated lipids. The altered lipid composition of the mutant had pronounced effects on chloroplast ultrastructure, thylakoid membrane protein and chlorophyll content, electron transport rates, and the thermal stability of the photosynthetic membranes. The change in chloroplast ultrastructure was due to a 48% decrease in the amount of appressed membranes that was not compensated for by an increased amount of nonappressed membrane. This resulted in a net loss of 36% of the thylakoid membrane per chloroplast and a corresponding reduction in chlorophyll and protein content. Electrophoretic analysis of the chlorophyll-protein complexes further revealed a small decrease in the amount of light-harvesting complex. Relative levels of whole chain and protosystem II electron transport rates were also reduced in the mutant. In addition, the mutation resulted in enhanced thermal stability of photosynthetic electron transport. These observations suggest a central role of polyunsaturated lipids in determining chloroplast structure and maintaining normal photosynthetic function and demonstrate that lipid unsaturation directly affects the thermal stability of photosynthetic membranes.

• DOE Contract Number: AC02-76ER01338
• OSTI ID: 7066345
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 90:3; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
BIOLOGICAL FUNCTIONS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHLOROPLASTS
ENZYME ACTIVITY
FUNCTIONS
HERBS
LIPIDS
MEMBRANES
MUTANTS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC MEMBRANES
PHYSIOLOGY
PLANTS
SYNTHESIS
TEMPERATURE EFFECTS
TOLERANCE