Plant Physiol, June 2002, Vol. 129, pp. 876-885
Photoinhibition in Mutants of Arabidopsis Deficient in Thylakoid
Unsaturation1
Perumal
Vijayan2 and
John
Browse*
Institute of Biological Chemistry, Washington State University,
Pullman, Washington 99164-6340
Thylakoid lipid composition in higher plants is characterized by a
high level of fatty acid unsaturation. We have screened four mutants of
Arabidopsis that have reduced levels of fatty acid unsaturation. Three
of the mutant lines tested, fad5,
fad6, and the fad3-2 fad7-2 fad8 triple
mutant, were more susceptible to photoinhibition than wild-type
Arabidopsis, whereas one mutant, fab1, was
indistinguishable from wild type. The fad3-2 fad7-2 fad8
triple mutant, which contains no trienoic fatty acids in its thylakoid
membranes, was most susceptible to photoinhibition. Detailed
investigation of photoinhibition in the triple mutant revealed that the
rate of photoinactivation of PSII was the same in wild-type and mutant
plants. However, the recovery of photoinactivated PSII was slower in
fad3-2 fad7-2 fad8, relative to wild type, at all
temperatures below 27°C. These results indicate that trienoic fatty
acids of thylakoid membrane lipids are required for low-temperature recovery from photoinhibition in Arabidopsis.
1
This work was supported by the U.S. National
Science Foundation (grant no. IBN-0084329) and by the Agricultural
Research Center, Washington State University.
2
Present address: Department of Plant Sciences,
University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, Canada S7N 5A8.
*
Corresponding author; e-mail jab{at}wsu.edu; fax 509-335-7643.
© 2002 American Society of Plant Physiologists
