Poster: Regulation of gene expression

Abs # 802: Comparing Arabidopsis Gene Expression in Response to Drought, Rehydration and Application of ABA and ABA Analogs Using Microarrays

Presenter:	Huang, Daiqing , daiqing.huang@nrc-cnrc.gc.ca
Authors	Huang, Daiqing  (A)   Abrams, Sue  (A)   Cutler, Adrian  (A)
Affiliations:	(A): National Research Council of Canada/Plant Biotechnology Institute

The phytohormone (+)-abscisic acid (ABA) plays an essential role in regulating responses to abiotic stresses such as drought. ABA analogs are structurally similar to natural ABA and many exhibit ABA-like effects. HyperABAs such as (+)-8'-acetylene ABA (PBI425) are analogs that are more persistent in vivo and exhibit stronger biological effects than ABA itself. Other ABA analogs such as (-)-ABA and (-)-2',3'-dihydroacetylenic abscisic alcohol (PBI51) exhibit weaker and selective or anomalous ABA-like biological effects. To reveal the organization of the ABA-induced signaling network required for stress responses, we used Arabidopsis oligonucleotide microarrays to compare gene expression changes of Arabidopsis in response to drought, rehydration, (+)-ABA, (-)-ABA, PBI51 and PBI425. Many genes were commonly regulated by ABA and the three ABA analogs. Microarray analysis showed that PBI425 was the most effective in regulating ABA-like gene expression followed by (+)-ABA, (-) ABA and PBI51. The order of effectiveness is consistent with their activities in bioassays, including prevention of wilting under drought. Most ABA or ABA analog-inducible genes were also induced after drought-treatment and repressed after rehydration. We also identified some genes that exhibited unusual patterns of expression, including a few that were induced by a specific ABA analog. These genes might be useful in revealing novel features of ABA signaling.