GENETICALLY ENGINEERED ALTERATION IN THE CHILLING SENSITIVITY OF PLANTS

THE chilling sensitivity of plants is closely correlated with the degree of unsaturation of fatty acids in the phosphatidylglycerol of chloroplast membranes 1-5. Plants with a high proportion of cis-unsaturated fatty acids, such as spinach and Arabidopsis thaliana, are resistant to chilling, whereas species like squash with only a small proportion are not. The chloroplast enzyme glycerol-3-phosphate acyltransferase seems to be important for determining the level of phosphatidylglycerol fatty acid unsaturation 6-9. Here we report that the level of fatty acid unsaturation of phosphatidylglycerol and the degree of chilling sensitivity of Nicotiana tabacum var. Samsum (tobacco) can be manipulated by transformation with complementary DNAs for glycerol-3-phosphate acyltransferases from squash and Arabidopsis. The genetic manipulation of fatty acid unsaturation is known to alter the chilling sensitivity of prokaryotes 10, and we have now demonstrated that it can also do so in higher plants.