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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

EFFECTS OF THE ONCOGENE ROLD IN ARABIDOPSIS THALIANA PLANTS

MAURO M.L.*, ZAGHI D.**, COSTANTINO P.*, ALTAMURA M.M.**

* Dipartimento di Genetica e Biologia Molecolare, Università La Sapienza, P.le Aldo Moro 5, Roma

marialuisa.mauro@uniroma1.it

** Dipartimento di Biologia Vegetale, Università La Sapienza di Roma, P.le Aldo Moro 5, Roma

flowering, Arabidopsis, rolD, meristems

The transition from the vegetative phase to the reproductive phase is a central developmental switch in the plant life cycle and is regulated by endogenous and exogenous factors such as light, nutrients, temperature, hormones, age, genes.

The oncogene rolD is derived from Agrobacterium rhizogenes plasmid T-DNA harboring a set of genes known to alter morphological and developmental pathways in plants.

We have demonstrated that rolD triggers an early flowering process in transgenic tobacco plants and stimulates floral organogenesis in cultured thin cell layers.

In order to take advantage of the genetic tools provided by Arabidopsis, we transformed rolD into this model plant and analysed the effect of the oncogene on the reproductive transition.

The results indicate that rolD induces floral meristem enhancement in Arabidopsis. The histological analysis shows the presence of meristems of inflorescence type in a number of axils of the rosette leaves higher in the transgenic plants than in the wild type .

Mature transgenic plants are smaller, produce a lot of coinflorescences, and a higher number of rosette leaves and of adventitious roots.

Thin cell layer experiments confirm the enhancement of flowering, but also supranumerary roots are produced, depending of the hormonal composition of the culture medium.

These results indicate that the effects of the oncogene rolD in Arabidopsis are substantially analogous to what observed in tobacco, and will be discussed in light of the recent elucidation in our laboratory of the biochemical function of the protein RolD.