Integrative Transcriptomics DataMining to Explore the Functions of TDP1a and TDP1b Genes in the Arabidopsis thaliana Model Plant

The tyrosyl-DNA phosphodiesterase 1 (TDP1) enzyme hydrolyzes the phosphodiester bond between a tyrosine residue and the 30-phosphate of DNA in the DNA–topoisomerase I (TopI) complex, being involved in different DNA repair pathways. A small TDP1 gene subfamily is present in plants, where TDP1a has been linked to genome stability maintenance, while TDP1b has unknown functions. This work aimed to comparatively investigate the function of the TDP1 genes by taking advantage of the rich transcriptomics databases available for the Arabidopsis thaliana model plant. A data mining approach was carried out to collect information regarding gene expression in different tissues, genetic backgrounds, and stress conditions, using platforms where RNA-seq and microarray data are deposited. The gathered data allowed us to distinguish between common and divergent functions of the two genes. Namely, TDP1b seems to be involved in root development and associated with gibberellin and brassinosteroid phytohormones, whereas TDP1a is more responsive to light and abscisic acid. During stress conditions, both genes are highly responsive to biotic and abiotic treatments in a time- and stress-dependent manner. Data validation using gamma-ray treatments applied to Arabidopsis seedlings indicated the accumulation of DNA damage and extensive cell death associated with the observed changes in the TDP1 genes expression profiles.