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 - 4.01

KNOX TRANSCRIPTION FACTORS IN MEDICAGO TRUNCATULA

E. DI GIACOMO, F. SESTILI, G. FRUGIS, D. MARIOTTI

Istituto di Biologia e Biotecnologia Agraria (IBBA), CNR, Area della Ricerca di Roma, Via Salaria Km. 29,300, 00016 Monterotondo Scalo (Roma), IT

transcription factors, Medicago truncatula, KNOX, legume

The model legume Medicago truncatula, a close relative of alfalfa, is a diploid and self-fertile species, with a relatively small genome (4 times that of Arabidopsis thaliana). It is an increasingly popular model plant which is now used worldwide, in particular for studying the molecular genetics of root symbioses.

Homeobox genes are known to play a role in developmental regulation. The knotted-like homeobox (KNOX) genes fall into two classes. The class I KNOX genes like KN1, STM, and KNAT1 are expressed in shoot meristems and loss of function mutations in different species revealed that KNOX genes are involved in the acquisition and maintenance of meristem identity. The function of class II KNOX genes is still undetermined.

In order to characterize KNOX function in Medicago truncatula, constructs for the overexpression of STM and KNAT1 from Arabidopsis and KN1 from maize, under the control of either 35S or a glucocorticoid inducible system (XVE), were obtained. Production of transgenic lines is in progress.

Through a search in Medicago database, five KNOX genes of M. truncatula have been identified. The corresponding ESTs have been requested to Noble Foundation and the preparation of constructs to overexpress or silence those genes is in progress.

The expression of endogenous KNOX genes have been investigated by RT-PCR and Northern blotting analysis.

In order to identify possible proteins that interact with KNOX factors in Medicago truncatula, we are going to prepare a cDNA library for two-hybrid analysis.