Elevated levels of high-melting-point phosphatidylglycerols do not induce chilling sensitivity in an Arabidopsis mutant
1995
Wu, J.R. | Browse, J.
Molecular species of phosphatidylglycerol that contain only 16:0, 18:0, and 16:1-trans tatty acids undergo the transition from liquid crystalline phase to gel phase at temperatures well above 20 degrees C. Several lines of evidence have been used to implicate elevated proportions of these high-melUng-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--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 degrees 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.
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