Integrative Plant Physiology
Fortes, Ana M , Santos, Filipa , Figueiredo, Andreia , Choi, Young , Silva, Marta , Sousa, Lisete , Pessoa, Fernando , Sebastiana, Mónica , Acioli, Bartolomeu , Palme, Klaus , Malhó, Rui , Pais, Maria Salomé .
Genomic approaches highlight the role played by sugars, auxins and polyamines during organogenic nodule formation in hop.
Organogenic nodules which regenerate plantlets can be obtained in hop (Humulus lupulus var. Nugget) by cultivating internodes on medium with indoleacetic acid, benzylaminopurine and sucrose (Fortes and Pais, 2000). DNA microarray-based gene expression profiling and metabolic profiling through 1H Nuclear Magnetic Resonance and two-dimensional techniques were used to understand mRNA-level control and to dissect metabolic pathways related to development of hop organogenic nodules. Using a 3,324-cDNA clone array, we profiled gene expression in different stages of organogenic nodule induction and development. After 15 and 28 days upon culture initiation (stage of nodule formation) 133 down- and up-regulated genes were found, which are involved in a variety of signal regulatory pathways. Several genes inhibited/ activated in organogenic nodules (after 28 days) showed an opposite trend, when compared to internodes, when hybridized with RNA from internodes cultured for 28 days on medium without growth regulators. This suggests that the mechanisms underlying morphogenesis rely on specific culture conditions and hormonal balance. The integration of datasets obtained through analysis of the transcriptome and metabolome suggested an important role of genes and amino acids related to oxidative stress. The expression profile of genes pivotal for energy metabolism, together with metabolites profile, suggested that these morphogenic structures gain energy through a heterotrophic, transport-dependent and sugar-degrading anaerobic metabolism. Polyamines and auxins are likely to regulate the expression of many genes related to organogenic nodule formation.
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1 - ICAT, Plant Molecular Biology and Biotechnology, Campus da FCUL, Campo Grande, Lisbon, 1749-016, Portugal
2 - ICAT
3 - Institute Biology Leiden
4 - FCUL
5 - Institute for Biology II, Albert- Ludwig University, Freiburg, Germany
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM