Ophir, R., Pang, X., Halaly, T., Venkateswari, J., Lavee, S., Galbraith, D., & Etti, O. r. (2009). Gene-expression profiling of grape bud response to two alternative dormancy-release stimuli expose possible links between impaired mitochondrial activity, hypoxia, ethylene-ABA interplay and cell enlargement. Plant Molecular Biology, 71(4-5), 403-423.
PMID: 19653104;Abstract:
A grape-bud-oriented genomic platform was produced for a large-scale comparative analysis of bud responses to two stimuli of grape-bud dormancy release, hydrogen cyanamide (HC) and heat shock (HS). The results suggested considerable similarity in bud response to the stimuli, both in the repertoire of responding genes and in the temporary nature of the transcriptome reprogramming. Nevertheless, the bud response to HC was delayed, more condensed and stronger, as reflected by a higher number of regulated genes and a higher intensity of regulation compared to the response to HS. Integrating the changes occurring in response to both stimuli suggested perturbation of mitochondrial activity, development of oxidative stress and establishment of a situation that resembles hypoxia, which coincides with induction of glycolysis and fermentation, as well as changes in the interplay between ABA and ethylene metabolism. The latter is known to induce various growth responses in submerged plants and the possibility of a similar mechanism operating in the bud meristem during dormancy release is raised. The new link suggested between sub lethal stress, mitochondrial activity, hypoxic conditions, ethylene metabolism and cell enlargement during bud dormancy release may be instrumental in understanding the dormancy-release mechanism. Temporary increase of acetaldehyde, ethanol and ethylene in response to dormancy release stimuli demonstrated the predictive power of the working model, and its relevance to dormancy release was demonstrated by enhancement of bud break by exogenous ethylene and its inhibition by an ethylene signal inhibitor. © 2009 Springer Science+Business Media B.V.
Galbraith, D. W., Bhosale, R., Boudolf, V., Cuevasa, F., Kumpf, R., Hu, Z., Van Isterdael, G., Lambert, G., Nowack, M., Smith, R., Vercauteren, I., De Rycke, R., Storme, V., Beeckman, T., Larkin, J., Kremer, A., Höfte, H., Kumpf, R., Maere, S., & De Veylder, L. (2017). A spatiotemporal DNA endoploidy map of the Arabidopsis root reveals roles for the endocycle in root development and stress adaptation.. Plant Cell.
Winkler, R. G., Frank, M. R., Galbraith, D. W., Feyereisen, R., & Feldmann, K. A. (1998). Systematic reverse genetics of transfer-DNA-tagged lines of Arabidopsis - Isolation of mutations in the cytochrome P450 gene superfamily. PLANT PHYSIOLOGY, 118(3), 743-749.
Galbraith, D. W., Janda, J., & Lambert, G. M. (2011). Multiparametric analysis, sorting, and transcriptional profiling of plant protoplasts and nuclei according to cell type.. Methods in molecular biology (Clifton, N.J.), 699, 407-429.
PMID: 21116995;Abstract:
Flow cytometry has been employed for the analysis of higher plants for approximately the last 30 years. For the angiosperms, ∼500,000 species, itself a daunting number, parametric measurements enabled through the use of flow cytometers started with basic descriptors of the individual cells and their contents, and have both inspired the development of novel cytometric methods that subsequently have been applied to organisms within other kingdoms of life, and adopted cytometric methods devised for other species, particularly mammals. Higher plants offer unique challenges in terms of flow cytometric analysis, notably the facts that their organs and tissues are complex three-dimensional assemblies of different cell types, and that their individual cells are, in general, larger than those of mammals.This chapter provides an overview of the general types of parametric measurement that have been applied to plants, and provides detailed methods for selected examples based on the plant model Arabidopsis thaliana. These illustrate the use of flow cytometry for the analysis of protoplasts and nuclear DNA contents (genome size and the cell cycle). These are further integrated with measurements focusing on specific cell types, based on transgenic expression of Fluorescent Proteins (FPs), and on analysis of the spectrum of transcripts found within protoplasts and nuclei. These measurements were chosen in particular to illustrate, respectively, the issues encountered in the flow analysis and sorting of large biological cells, typified by protoplasts; how to handle flow analyses under conditions that require processing of large numbers of samples in which the individual samples contain only a very small minority of objects of interest; and how to deal with exceptionally small amounts of RNA within the sorted samples.
Liwińska, E., Lambert, G. M., & Galbraith, D. W. (2002). Factors affecting nuclear dynamics and green fluorescent protein targeting to the nucleus in Arabidopsis thaliana roots. Plant Science, 163(3), 425-430.
Abstract:
Nuclear movement and targeting of a green fluorescent protein (GFP)-nuclear localization sequence (NLS)-β-glucuronidase (GUS) chimeric protein to the roots of transformed Arabidopsis has been studied using time lapse analysis. To characterize the mechanism governing this movement, metabolic inhibitors, and chemicals that alter the concentrations of divalent cations in the cell were applied. Flow cytometry was used to examine the condition of nuclear membranes. The results showed that nuclear movement in Arabidopsis roots was energy-dependent. The concentration of magnesium ions seemed to play a crucial role in the movement of the nuclei and targeting of the chimeric GFP protein into the nucleoplasm. In contrast, alterations in concentration of calcium ions did not affect either nuclear dynamics or nucleoplasmic GFP accumulation. The results are discussed in terms of some of the physiological processes occurring within the cell. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
