Poster: Regulation of gene expression
Abs #
785: An Arabidopsis vacuolar invertase gene family responds to sugar and ABA signals
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Presenter: |
Huang, Li-Fen , hlf0326@ufl.edu |
Authors | Huang, Li-Fen (A) Koch, Karen E (A) | | Affiliations: |
(A): Plant Molecular and Cellular Biology Program, University of Florida
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Sucrose is the major carbon and energy source for most importing plant cells, where invertases play a primary role in cleaveage of each sucrose into two hexoses. Since both hexoses and sucrose are sensible sugars, invertases can have profound effects on sugar-regulated genes through influence on hexose/sucrose balance. These sugars also affect both biosynthesis and sensing of the phytohormone, abscisic acid (ABA), thus contributing to the extensive cross talk evident between ABA and sugar in analysis of Arabidopsis responses. Based on gene chip analysis, at least one vacuolar invertase gene in Arabidopsis is induced by ABA. The nature of the invertase gene family in Arabidopsis is thus centrally relevant to the sugar / ABA interface in this species. In Arabidopsis, there are two vacuolar invertase genes, Atβfruct3 and Atβfruct4, plus six cell wall invertase genes. Previous work has shown that transcriptional regulation and control of mRNA levels contribute prominently to activity of vacuolar invertases in Arabidopsis and maize. Methods were thus developed for quantitative Q-RT-PCR and gene-specific amplicons for each family member. Gene specificity was tested for each set of primers and probes in pair-wise comparisons of cDNAs for all eight invertase family members. Equal signal was generated by each cDNA, and signal from cross-hybridization to other invertase genes was very low (between 10-5 and 10-8). Quantitative values were obtained for vacuolar invertases by comparison with products of their in vitro transcription. Use of this approach showed that the Atβfruct3 was sugar up-regulated while the Atβfruct4 gene was sugar repressed in young Arabidopsis plants. In addition, only Atβfruct3 responded to ABA, whereas the other was ABA-insensitive.
