Mechanisms of Gene Regulation
Majumdar, Rajtilak , Mitchell, Jeff , Sanders, Scott , Minocha, Subhash .
Analysis of the expression of key polyamine biosynthetic genes in Arabidopsis.
Polyamines are involved in many essential physiological phenomena relating to growth, development and stress responses in plants. Using promoter::GUS fusion approach, spatial and temporal expression of two known paralogues each of arginine decarboxylase (ADC), S-adenosylmethionine decarboxylase (SAMDC) and glutamate decarboxylase (GAD) were studied in all tissues and organs during the entire life of Arabidopsis thaliana. The results show that ADC1 was expressed moderately in cotyledonary veins and lamina, hypocotyl and petiole vascular tissues, apical meristems with low expression in root tips during the first 15 days post germination (DPG). Moderate expression of ADC2 was noticed in cotyledonary veins, hypocotyl veins and root vascular tissues (except root tips) following germination, that gradually declined by 15 DPG. In mature plants ADC2 expression was high in stem, leaf trichomes and moderate in rachis, flowers and siliques while ADC1 expression was more in flowers, siliques and leaves. Uniform expression of SAMDC1 in all organs was observed at early stages, but its expression was localized in only a few tissues in mature plants, while SAMDC2 expressed highly in rachis, rosette leaves, flowers and siliques. GAD1 showed high expression in all parts of the plant during first 15 DPG while the expression of GAD2 was limited to cotyledon and hypocotyl veins. Bioinformatics study of promoter regions of the six genes revealed presence of several common motifs; e.g. MYB1AT (dehydration response), GAREAT (GA response) and ABRE (ABA response). This is the most comprehensive analysis of the expression of a set of genes for any metabolic pathway in Arabidopsis. Detailed analysis of the expression of each gene in response to salinity and osmotic stress is currently under way.
Log in to add this item to your schedule
1 - University of New Hampshire, Plant Biology, 46 College Road, Rudman Hall (Minocha Lab), Durham, NH, 03824, USA
2 - UNH
3 - University of New Hampshire, Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM