Transcriptional profiling after inhibition of cellulose synthesis by thaxtomin and isoxaben in Arabidopsis thaliana suspension cells
ABSTRACT: Transcriptional profiling after inhibition of cellulose synthesis by thaxtomin A and isoxaben in Arabidopsis thaliana suspension cells; Perturbations in the cellulose content of the plant cell wall lead to global modifications in cellular homeostasis, as seen in cellulose synthase mutants or after inhibiting cellulose synthesis. In particular, application of inhibitors of cellulose synthesis such as thaxtomin A (TA) and isoxaben (IXB) initiates a programmed cell death (PCD) in Arabidopsis thaliana suspension cells that is dependent on de novo gene transcription. To further understand how TA and IXB activate PCD, a whole genome microarray analysis was performed on mRNA isolated from Arabidopsis suspension cells exposed to TA and IXB. More than 75% of the genes upregulated by TA were also upregulated by IXB, including genes encoding cell wall-related and calcium-binding proteins, defence/stress-related transcription factors, signalling components and cell death-related proteins. Comparisons with published transcriptional analyses revealed an important subset of genes generally induced in response to various biotic and abiotic stress. Experiment Overall Design: TA, IXB and methanol (control) were added to Arabidopsis thaliana suspension cells three days after sub-culture. Cells were harvested for RNA isolation and frozen in liquid nitrogen after 6 hours of contact with the inhibitors. Samples consisted of four replicates for each condition. A total of 12 Affymetrix GeneChips® were used in this study, which correspond to 12 RNA samples from the four biological replicates for each of the TA, IXB or methanol addition.