Cold responses of<i>Arabidopsis</i>mutants impaired in freezing tolerance

Abstract

Mutants of Arabidopsis thaliana L. (Heynh), characterized as deficient in their freezing tolerance after cold acclimation, were surveyed for some of the normal responses to cold exposure. In foliar tissue, the coldinducibility of three proteins, the levels of sucrose and glucose, the fatty acyl composition of lipids, and the accumulation of anthocyanin was examined. Four mutations (sfr3, sfr4, sfr6, and sfr7) reduced or eliminated the accumulation of anthocyanin during cold acclimation. One mutation (sfr4) prevented the normally cold-induced elevation of sucrose and glucose levels; both sfr4 and another mutation (sfr7) affected fatty acid composition after (and only after) cold acclimation. On the other hand mutations sfr1, sfr2 and sfr5 did not differ significantly from the wild type in any of the parameters tested, suggesting that they have other, perhaps highly specific, effects on lowtemperature responses.