Microarray analysis reveals transcriptional differences in tobacco cells cultured without and with Al.

Using our microarray data, we identified 1, 702 probes with known functions (661 upregulated and 1, 041 downregulated) with changes of at least 2-fold in their differential transcript levels with significance (P < 0.05) under Al treatment condition, compared with control condition in SL cells (note that some probes within the 1, 702 probes carry the same TIGR ID and/or UniGene ID). Microarray analysis of up- and down-regulated genes under Al exposure and following Gene Ontology (GO) enrichment analysis for biological process revealed only one GO term for the upregulated genes, ‘response to chitin’, annotated with genes coding MAP kinase (WIPK) and transcription factors (NtMYB3, NtERF1) but nine GO terms for the downregulated genes, including ‘cell wall loosening’ and ‘lipid transport’, annotated with genes coding expansins (NtEXPAs) and lipid transport protein (LTP) and LTP-like (NtLTP3, NtEIG-C29), respectively. Differential expression analysis between without (control) and with Al (100 µM AlCl3) under shaking condition, 3 different replicate of each treatments.