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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Oral Communication Abstract

OSMADS18: A RICE MADS BOX FACTOR THAT CHANGES PARTNERS DURING PLANT DEVELOPMENT AND PROMOTES FLOWERING

KATER M.*, MASIERO S.*, PELUCCHI N.**, FORNARA F.**, SARI-GORLA M.*, COLOMBO L.**

* Dipartimento di Genetica e di Biologia dei Microrganismi, Università di Milano

**Dipartimento di Biologia, Università di Milano

MADS-box genes represent an important transcription factor family involved in different steps of vegetative and reproductive development. Their role is conserved at different evolutionary levels.

We report the isolation and analysis of a MADS box gene, OsMADS18 (Oryza sativa MADS box gene n°18). The predicted OsMADS18 amino acid sequence is homologous to PETUNIA FLOWERING GENE (PFG) and the expression analysis showed that the transcript can be observed in all plant tissues and in particular in meristematic tissues. The transcript starts to be expressed six weeks after germination and its level increases progressively during the vegetative phase reaching a maximum during the transition to flowering.

Transgenic rice plants overexpressing OsMADS18 show growth reduction and flower early, compared to wild type.

Yeast two-hybrid screens using OsMADS18 as bait resulted in the isolation of four MADS box genes tissue specifically expressed, indicating that OsMADS18 might have different functions during rice development when interacting with different partners. One of them is OsMADS47 which has high homology with SVP, a repressor of flowering in Arabidopsis thaliana. The putative role of the OsMADS18-OsMADS47 heterodimer in flowering will be discussed.