Abstract

A selection system is proposed for plant transformation that is exclusively based on genetic information already present in the host plant and that does not require antibiotic resistance genes. The driving force for this approach is the public concern about a potential spread of antibiotic resistance genes in soil and intestinal bacteria possibly accentuated by the agricultural use of transgenic crops. The project is based upon truncated tubulins lacking the binding site for carbamates. The expression of this truncated tubulin is driven by the homologous tubulin promotor within a DNA fragment devoid of exogenous sequences (minimal expression unit). The suitability of this selection system is demonstrated for rice as a model system for Graminean crops.

Objectives

• Production of a selection marker cassette (tubulin promotor, coding sequence coding for alpha-tubulin conferring resistance to carbamate herbicides, and full-length beta-tubulin).
• Transformation of rice with this construct and establishment of a selection and transformation protocol based on carbamates.
• Cotransformation of the selection marker cassette with rice phytochrome as model test and assays for expression and functionality of the transgene.
• Use of "clean DNA" technology to avoid extraneous backbone and vector sequences.

• Production of a selection marker cassette (tubulin promotor, coding sequence coding for alpha-tubulin conferring resistance to carbamate herbicides, and full-length beta-tubulin).
• Transformation of rice with this construct and establishment of a selection and transformation protocol based on carbamates.
• Cotransformation of the selection marker cassette with rice phytochrome as model test and assays for expression and functionality of the transgene.
• Use of "clean DNA" technology to avoid extraneous backbone and vector sequence

• Transformation cassettes: homologous tubulin promotor driving balanced expression of tubulin dimers that confer carbamate resistance.
• Carbamate-resistant rice plants that do not contain any DNA sequences of foreign origin.
• A selection protocol based on carbamate and possibly cold resistance.
• Rice plants that overexpress phytochrome and are carbamate-resistant and transformation vectors for phytochrome overexpression.
• Data on trait stability, regulation of the tubulin system and potential side effects of the selection marker.

Contacts

Coordinator

• Albert-Ludwigs-Universität Freiburg Institut für Biologie II / GERMANY

Participant

• Diego BREVIARIO / Istituto Biosintesi Vegetali Centro Nazionale di Ricercha / ITALY
• Paul CHRISTOU / John Innes Centre UNITED KINGDOM