Specific transcriptomic response in the shoots of Arabidopsis thaliana after exposure to Al rhizotoxicity: - potential gene expression biomarkers for evaluating Al toxicity in soils

Background and aims Crop production is impaired by excessive soil minerals and salts, such as sodium chloride, heavy metals, and aluminum (Al). These stressors may induce specific damage- and stress-responses in the shoots, which can be evaluated by molecular level. Al specific responses in the shoots were analyzed whether it can evaluate plant conditions affected by Al in soils. Methods We performed a comparative microarray analysis of Al, Cd, Cu and NaCl rhizotoxic treatments on the shoots of Arabidopsis to identify specifically Al-inducible genes. Results and conclusion Comparative transcriptomic analyses showed that a different set of genes responded to each rhizotoxic treatment. The heavy metals Cd and Cu commonly activated the transcription of genes encoding enzymes detoxifying reactive oxygen species (ROS). NaCl activated the expression of genes for the DREB2A transcription factor and LTPs . Al activated the transcription of genes, such as ALS3 or PGIP1 , regulated by the STOP1 transcription factor, which upregulates the expression of some Al-responsive genes in roots. The STOP1-regulated transcription response to Al stress was present in the shoot. We confirmed the upregulation of these genes in acid soil culture, showing that they may be used as transcriptional biomarkers that assess Al toxicity in acid soil.