THE PLANT CELL, Vol 7, Issue 1 17-27, Copyright © 1995 by American Society of Plant Biologists
Elevated Levels of High-Melting-Point Phosphatidylglycerols Do Not Induce Chilling Sensitivity in an Arabidopsis Mutant
J. Wu and J. Browse
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
Molecular species of phosphatidylglycerol that contain only 16:0, 18:0, and
16:1-trans fatty acids undergo the transition from liquid crystalline phase
to gel phase at temperatures well above 20[deg]C. Several lines of evidence
have been used to implicate elevated proportions of these
high-melting-point molecular species as a major cause of plant chilling
sensitivity. In the fatty acid biosynthesis 1 (fab1) mutant of Arabidopsis,
leaf phosphatidylglycerol contained 43% high-melting-point molecular
species[mdash]a higher percentage than is found in many chilling-sensitive
plants. Nevertheless, the mutant was completely unaffected (when compared
with wild-type controls) by a range of low-temperature treatments that
quickly led to the death of cucumber and other chilling-sensitive plants.
Our results clearly demonstrate that high-melting-point
phosphatidylglycerols do not mediate classic chilling damage. However,
growth of fab1 plants was compromised by long-term (>2 weeks) exposure
to 2[deg]C. This finding and other observations are consistent with a
proposition that plants native to tropical and subtropical regions have
evolved many traits that are incompatible with long-term growth or
development in cooler climates but that may confer selective advantages at
high temperatures.
