Plants are constantly subjected to environmental changes, e.g. mechanical forces and temperature fluctuations which they perceive through signal transduction pathways.  DNA constructs for Agrobacterium-mediated transformation into Nicotiana plumbaginifolia were prepared.  The Ca²⁺-sensitive luminescent protein, aequorin was placed in frame with the nuclear localisation signal (NLS) peptide of the simian virus SV40 Large T-antigen, Xenopus laevis' nucleoplasmin, and high mobility group protein, HMG1 from Pisum sativum.  After analysing individual transformants, nucleoplasmin was shown to successfully target aequorin to nuclei.  These plants, together with plants transgenic for cytosolic aequorin were used to study Ca²⁺ dynamics when exposed to the environmental stimuli, such as wind.  Wind induced immediate Ca²⁺ transients in the cytoplasm and nucleus (Fig. 1).
    Heat shock induced a prolonged but transient increase in cytoplasmic Ca²⁺ that was dependent on the temperature applied (Fig. 2A).  Seedlings pretreated with external Ca²⁺ or EGTA showed enhanced or diminished Ca²⁺ response respectively (Fig. 2B) and exhibited enhanced or diminished thermotolerance.  This suggest that an increase in cytosolic Ca²⁺ levels is required for the acquisition of heat-induced thermotolerance.
 
  Fig.1                   Fig. 2

NB. The nucleoplasmin-aequorin construct was prepared by Dr. C. Olivari.  Heat shock calcium measurements and heat shock-induced thermotolerance were carried out in collaboration with Prof. M. Gong.
 
 

Personal information

Name:
Arnold H. van der Luit

Address per October 1, 1998:
University of Amsterdam
Institute of Molecular Cell Biology
BioCentrum Amsterdam, University of Amsterdam
Kruislaan 318, 1098 SM  Amsterdam, Netherlands
 
Telephone 31 20 5257933 or 5257942
Fax 31 20 5257934

Electronic mail:
 luit@bio.uva.nl

 

Date of birth:
December 5, 1968 in Leimuiden (Netherlands).
 

Training and Education

Sep. 1990 - May. 1991:
Molecular analysis of Ds containing T-DNAs in transgenic Arabidopsis plants, as a training period in order to obtain Bachelors degree in the group of Prof. M. van Montagu with Dr. M. van Lijsebettens at the University of Ghent in order to obtain a Bachelor degree in bio-engineering at the Polytechnical School in Delft.

Sep. 1992 - Feb. 1993:
Characterisation and hormonal regulation of a novel Flavonoid gene, ant17 from Petunia hydrida as a training period in the group of Prof. J.N.M. Mol with Dr. D. Weiss at the Free University of Amsterdam for a Master degree in Biology.

Oct. 1993 - Jun. 1994:
Targeting of aequorin to the nucleus of Nicotiana plumbaginifolia as an extra training-period in the group of Prof. A.J. Trewavas at the University of Edinburgh.

Oct. 1994 - Oct. 1997:
Ph.D. in Biology "The Regulation of Calmodulin Gene Expression by Nuclear Calcium in Plants" with Professor. A.J. Trewavas at the University of Edinburgh. Funded by an EC Fellowship.

Oct. 1997 - Sep. 1998:
The Regulation of Calmodulin Gene Expression by Nuclear Calcium in Plants.  Post-doctoral position with Professor A.J. Trewavas at the University of Edinburgh.
 
From Ocotber 1, 1998:
The Identification of lipid signalling pathways that are activated in tomato cell suspension cultures by elicitors form the leaf pathogen Cladosporium fulvum with Dr. A. Musgrave at the University of Amsterdam (see corresponding address).
 

Publications: 

Van der Luit, A.H., Olivari, C., Haley, A., Knight, M.R. and Trewavas, A.J.  Distinct Calcium Signalling Pathways Regulate Calmodulin Gene Expression in Nicotiana plumbaginifolia. Submitted

Malhó, R., Moutinho, A., Van der Luit, A.H., and Trewavas, A.J. Spatial characteristics to calcium signalling: the calcium wave as a basic unit in plant cell signalling. Phil. Trans. Royal Soc. Biol. Sci. (in press).

Gong, M., Van der Luit, A.H., Knight, M.R. and Trewavas, A.J. (1998).  Heat shock-induced changes in intracellular calcium in tobacco seedlings. Plant Physiol. 116 (1): 429-437.

Weiss, D., Van der Luit, A.H., Knegt, E., Vermeer, E., Mol, J.N.M. and Kooter, J.M. (1995). Identification of endogenous gibberellins in Petunia flowers: Induction of anthocyanin biosynthetic gene expression and the antagonistic effect of abscisic acid. Plant Physiol. 107, 695-702.

Weiss, D., Van der Luit, A.H., Kroon, J.T.M., Mol, J.N.M. and Kooter, J.M. (1993). The Petunia homolog of the Antirrhinum majus candi and Zea mays A2 flavonoid genes; homolog to flavanone 3-hydroxylase and ethylene forming enzyme.  Plant Mol. Biol. 22, 893-897.