ABSTRACT: Cold stress impedes the growth and development of plants, restricts the geographical distribution of plant species, and impacts crop productivity. In this study, we analyzed the Arabidopsis thali-ana transcriptome to identify genes with differential expression (DEGs) in 14-day-old plantlets exposed to temperatures of 0°C, 4°C, and 10°C for 24 h, compared to the 22°C control group. We found 31 genes shared among three low temperatures, with 9 genes common to 0°C-4°C, 8 genes to 4°C-10°C, and 2 genes to 0°C-10°C among the top 50 cold-induced genes from each tempera-ture. Our data revealed that genes, such as galactinol synthase 3 (Gols3, At1g09350), CIR1 (At5g37260), DnaJ (At1g71000), and At5g05220 (unknown function), exhibited the highest ex-pressions at 0°C and 4°C during the 24, 48, and 72-h intervals. We also studied genes from the UDP-glycosyltransferase (UGT78) family, including At5g17030 (D3), At5g17040 (D4), At5g17050 (D2), and At1g30530 (D1), which showed increased expression at low temperatures compared to plantlets at 22°C for 24 h. Gene ontology analysis revealed that DEGs highly en-riched were found in biological processes including “RNA secondary structure unwinding” and “rRNA processing” induced at the three low temperatures, whereas processes related to photo-synthesis were repressed. Our findings indicated upregulation in the expression of four RNA hel-icases (RH13, RH48, RH32, and RH29), belonging to the “RNA secondary structure unwinding” category, mainly at 0°C and 4°C. This study provides valuable information on the molecular mechanisms that activate Arabidopsis thaliana in its early response to these three low tempera-tures.
