Poster: Genomic & proteomic resources

Abs # 869: Microarray analysis of arabidopsis genome response to aluminum stress

Presenter:	Goodwin, Shirlean , sgoodwin@memphis.edu
Authors	Goodwin, Shirlean  (A)   Sutter, Thomas R (A)
Affiliations:	(A): W. Harry Feinstone Center for Genomic Research, University of Memphis

To better understand the mechanisms involved in aluminum (Al) toxicity and tolerance in plants, microarray technology was used to evaluate changes in gene expression in Arabidopsis thaliana under Al stress. With the use of Affymetrix Arabidopsis ATH1 Genechip, a comparison of RNA expression profiles was made between control and Al-treated Arabidopsis seedlings. A total of 260 genes were identified as Al-responsive. Eighty-eight genes were shown to be up-regulated and 172 were down-regulated; comprising 1.1% of the 24,000 Arabidopsis genes. Real-time RT-PCR was used to confirm the microarray data. RNAs associated with known protein functions were classified into categories. Analysis showed that a large number of transcription factors and several putative signaling components were up-regulated by aluminum. Chloroplast structural and photosynthetic genes were, in general, down-regulated. A number of previously identified Al-responsive genes showed similar expression pattern changes in this study. For example, GST, Auxin-regulated, Peroxidase, and Chitnase, were found to be up-regulated by Al-stress, whereas, genes such as Wali 3 and Wali 4, were down-regulated. We also identified several Al-up-regulated genes involved in vacuolar signaling, sorting and docking. Three genes up-regulated by Al-stress, Ras GTP-binding protein, ABC-cassette binding protein, and AtELP1 receptor, have previously been documented as responsive to drought and/or oxidative stress and may also play important roles in the detoxification of Al ions by tranportation and storage into root vacuoles.