Temperature and Light modulate the trans-delta3-hexadecenoic acid content of phosphatidylglycerol: light-harvesting complex II organization and non-photochemical quenching.
The interaction of light and temperature in the modulation of the trans-delta3-hexadecenoic acid (trans-16:1) content of phosphatidylglycerol (PG) in winter rye (Secale cereale L.) was assessed and related to the organization of light-harvesting complex II (LHCII). Increasing the growth irradiance from 50 to 800 micromol m(-2) s(-1) at 20 degrees C resulted in a 1.8-fold increase in the trans-16:1 content in PG which favoured a greater preponderance of oligomeric LHCII, measured in vitro as the ratio of oligomer : monomer. Similar irradiance-dependent increases were observed during growth at 5 degrees C; however, 1.4-fold lower trans-16:1 contents and lower LHCII oligomer : monomer ratios were observed compared with growth at 20 degrees C and the same irradiance. These trends were also observed under natural field conditions. Thus, the accumulation of trans-16:1, as well as the organization of LHCII are modulated by both growth irradiance and growth temperature in an independent but additive manner. We also examined how changes in the supramolecular organization of LHCII affected the capacity for non-photochemical quenching (q(N)) and photoprotection via antenna quenching (q(O)). While q(O) was positively correlated with q(N), there was no correlation with either LHCII organization or xanthophyll cycle activity under the steady-state growth conditions examined.
Gray
Gordon R
GR
Department of Plant Sciences, University of Saskatchewan, Saskatoon SK S7N 5A8, Canada. gr.gray@usask.ca
Ivanov
Alexander G
AG
Król
Marianna
M
Williams
John P
JP
Kahn
Mobashoher U
MU
Myscich
Elizabeth G
EG
Huner
Norman P A
NP
D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism*; D010715:Phosphatidylglycerols / Q000378:metabolism*; D010777:Photochemistry; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D013696:Temperature; D024341:Xanthophylls / Q000378:metabolism
D045342:Light-Harvesting Protein Complexes; D010169:Palmitic Acids; D010715:Phosphatidylglycerols; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D024341:Xanthophylls; C093821:hexadecenoic acid