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 - 4.14

A RCC1-LIKE GENE CONTROLS GROWTH AND DEVELOPMENT IN ARABIDOPSIS

V. VALIANTE*, F. CONDIGLIO*, S. GRILLO*, R. SERRANO**, A. LEONE***

*) Institute of Plant Genetics(CNR-IGV) - Research dDvision of Portici, Naples, Italy

**) Instituto de Biologia Molecular y Celular de Plantas, CSIC, Valencia, Spain

***) Dept. of Pharmaceutical Sciences, University of Salerno, Italy

Arabidopsis, plant growth and development, cell cycle gene regulation

Beta-propellers are emerging as novel protein domains promoting protein-protein interaction and binding to ligands, sugars, prosthetic groups and ions B-propellers modules are formed by a variety of divergent consensus aminoacid sequences, found in polypeptides involved in different cellular activities (e.g. WD motifs of G protein b subunit, kelch repeat proteins etc.

An Arabidopsis gene encoding a putative b-propeller protein was identified as able to restore growth of the osmotic unstable mpk-ppz1- yeast mutant in absence of sorbitol. Besides the presence of seven RCC1-like motifs, the protein contains also a conserved putative cyclin binding domain.

A functional gain and loss approach was used to get insights into the role of this plant gene. Compared to wild type plants, T4 over-expressing plants had a stunted vegetative growth and a reduced number of flowers and siliques. Antisense plants were very vigorous, with a larger rosette and leaf size and a significant higher number of inflorescence and siliques. These data suggest that the gene may act as a negative regulator of Arabidopsis plant growth, as further confirmed by phenotypic analysis of a mutant from the Salk knock-out collection. Cyclin, ICK and CDK genes were differently regulated in sense and antisense plants, indicating that the gene might be involved in plant cell cycle.