Changes in the content of fatty acid desaturases gene transcripts for Arabidopsis plants under adaptation to hypothermia

Abstract

Changes in the content of acyl-lipid desaturases gene transcripts in Arabidopsis (Arabidopsis thaliana Heynh. (L.), ecotype Columbia) plants subjected to low temperature hardening for 5 days at 2°C were investigated. In the course of the experiments with hourly dynamics of plant chilling, it was established that the genes under study by their responses to cold action can be separated into two groups. The genes of the first group represented by ADS2, FAD2, and FAD7 are characterized by the amount of their transcripts that rapidly increase even for the first 2–4 h of cold exposition, while the same value for the genes FAD3, FAD6, and FAD8 belonging to the second group remained unchanged under the same conditions. The experiments with the above hardening dynamics provided evidence for consecutive character of genes ADS2, FAD2, and FAD7 transcript accumulation, where the process for ADS2 was sharply intensified even for the first days of hardening, while that for other two genes achieved maximal intensity only on the fourth day of hardening. These results, taken together, lead to the conclusion that the agreeing in time increase in the transcript content of genes ADS2, FAD2, and FAD7 encoding Δ9-, Δ12-, and ω3-desaturases resulted in the change of FAs composition of chloroplast lipids. Increasing portion in them of triene FAs during hardening time provided the maintenance of chloroplast membranes in a native state allowing the Arabidopsis plant to successfully adapt to hypothermia.