EN
Formaldehyde (HCHO) is highly toxic to all living organisms. In this study, the toxic effects of HCHO exposure on Arabidopsis thaliana were analyzed at the physiological and transcriptional levels. Exposure to 2 mM HCHO led to a significant decrease in plant growth and a massive increase in anthocyanin content. A remarkable increase in H₂O₂ content and elevation in the levels of protein carbonyl and DNA–protein crosslinks were detected in Arabidopsis plants exposed to 2 mM HCHO for a period of 17 h. In contrast, the malondialdehyde content decreased during this period. These results suggested that HCHO stress caused significant oxidative damage to proteins but not membrane lipids during this period. The Affymetrix ATH1 Genome Array was used to evaluate changes in the global gene expression in Arabidopsis plants exposed to 2 mM HCHO over the 17-h period. A total of 620 transcripts were shown to be regulated significantly (at least twofold). The number of down-regulated genes (467) was approximately threefold greater than the number of up-regulated genes (154). Down-regulation in a large number of genes encoding cell surface receptors, cell wall proteins, enzymes related to toxin metabolism, peroxidase, disease resistance protein, multidrug and toxin extrusion and ATP-binding cassette transporters might be an important part of the toxic effects of HCHO exposure on Arabidopsis at the transcriptional level. Up-regulation in many genes encoding heat shock proteins was suggested to be an important protective mechanism for Arabidopsis plants in response to the oxidative damage of proteins. Verification of microarray data by reverse transcription polymerase chain reaction analysis identified typical HCHO-induced and -repressed genes.