Poster: Late and Moved Abstracts

Abs # 978: Microarray analysis of changes in Arabidopsis P450 gene expression following the application of growth hormones and signaling molecules

Presenter:	Ali, Shahjahan , shahjahan@life.uiuc.edu
Authors	Ali, Shahjahan  (A)   Thimmapurum, Jyothi  (B)   Band, Mark  (C)   Werck-Reichhart, Daniele  (D)   Schuler, Mary A (A)
Affiliations:	(A): Department of Cell and Structural Biology, University of Illinois (B): Keck Center for Bioinformatics, University of Illinois (C): Keck Center for Functional Genomics, University of Illinois (D): Institute of Plant Molecular Biology, CNRS, Strasbourg, France

Plant growth hormones are endogenous chemicals synthesized within plant cells at very low concentrations. They stimulate and regulate plant growth and development throughout the plant life cycle and mediate responses to environmental stimuli. P450 gene-specific microarray techniques have been used to define changes in P450 gene expression that occur following the application of the growth hormones ABA, IAA and brassinosteroids (BR). For this, eight-day-old Arabidopsis thaliana seedlings were treated either with 50 ìM ABA, 100 ìM IAA or 1 ìM epibrassinosteroids for 1 to 24 hours. Microarray analysis indicated that 36, 20 and 3 P450 transcripts were induced at least two-fold by ABA, IAA and BS, respectively, over their levels in control seedlings receiving no hormonal treatment. In concert with these changes, 43, 10 and 5 physiological function marker transcripts were induced significantly by ABA, IAA and BR. Contrasting with these inductions, 29 P450 and 49 marker transcripts were repressed by ABA, 19 and 10 by IAA and 11 and 2 by BR. Although each of these hormones induces and represses independent sets of genes, some distinct overlaps in responses exist. A number of genes induced/repressed by these growth hormones show overlaps with the sets of genes induced/repressed by defense signaling molecules (MeJ, SA and BION; from our previous microarray experiments) indicating that existence of a network of signaling pathways mediating responses to abiotic and biotic stresses.