Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 5.19

A GENE-TRAPPING APPROCH TO STUDY THE CORRELATION BETWEEN CALMODULIN AND PCD IN ARABIDOPSIS THALIANA

A. DE FRANCESCO, M. LANDONI, F. FOGLIA, C. TONELLI

Università degli Studi di Milano, Dipartimento di Scienze Biomolecolari e Biotecnologie, Via Celoria 26, 20133 Milano

Gene-trap, Calmodulin, PCD, Arabidopsis

We report the preliminary characterization of a calmodulin 2 (cam2) mutant, isolated in the Exotic (Exon trapping insert consortium) collection of Arabidopsis, obtained using a gene-trapping system based on the Ac/Ds transposons of maize.

In the cam2 mutant the transposon, containing the GUS reporter gene, is inserted in the At2g41110 gene, corresponding to Calmodulin 2 (Cam2).

Calmodulins (CaMs) are members of Ca⁺⁺-binding proteins family, identified in all the eukaryotes examined. When CaMs bind to Ca⁺⁺, there is a conformational change and the activated protein is able to interact with its targets.

In Arabidopsis there are six Cam genes, with a highly conserved primary structure, and others Calmodulin-like genes.

The consequence of the loss of function of Cam2 is an altered phenotype: cam2 plants are shorter than wild type and the leaves of the rosette show necrotic lesions very early during development.

Cell death in plants can occur as necrosis or as genetically defined programmed cell death (PCD), an active process involved in various developmental processes and in the interaction with pathogens.

To better understand the nature of these lesions we have used histochemical analysis to reveal the presence of specific markers associated with PCD.

We have also analyzed in wild type and mutant plants, the expression level of PR (pathogen-related) genes, constitutively expressed in “lesion mimic” mutants and SAG (senescence-associated) genes, known to accumulate during senescence.

Finally, we have grown wild type and cam2 plants in different media to verify if these necrotic lesions could be a consequence of a nutritional deficiency.