Abstract

The project seeks to exploit plant-specific gene silencing mechanisms to develop new strategies for the prevention of transgene silencing and for the controlled use of gene silencing for the inactivation of endogenous genes and gene families in crop plants. The project combines novel basic research elements with the application of these results in modern agriculture for the benefit of the consumer and European industry, as it is expected to develop strategies for a safe and reliable use of a commercially highly important technology.

Objectives

The project focuses on the understanding of the molecular mechanism that regulates transcriptional and post-transcriptional inactivation (silencing) of transgenes and endogenous genes in plants. In a joint effort of ten academic and two industrial partners, this proposal will exploit and combine expertise, genetic material, and research and production facilities to deliver new tools and products for European industry.

The programme is based on the achievements of a previous network that has been highly successful in defining the target features that make transgenes prone to silencing and isolating the first endogenous genes that regulate silencing. The next step towards an efficient exploitation of this background material and know-how will be to develop strategies for the prevention of transgene silencing in crop plants, to design transgene vectors and target lines for a reliable silencing of endogenous plant genes or gene families, and to identify the individual host genes that regulate silencing mechanisms and endogenous target genes of silencing mechanisms.

Description of the work

The workplan has been divided into five Workpackages.

Workpackage 1 addresses the problem of unstable expression of transgenes in transgenic plants. It aims to improve vectors and cultivation conditions that guarantee a silencing-insensitive transgene composition and to define the most favorable integration regions for stable transgene expression.

Workpackage 2 focuses on the optimisation of recombinant constructs that ensure the use of PTGS for a constitutive or selective induction of silencing.

Workpackage 3 exploits the cloned silencing genes to modulate the expression of silencing functions in an approach to enhance the silencing potential of plants.

Workpackage 4 will dissect the individual silencing mechanisms and their role in the regulation of endogenous genes.

Workpackage 5 will exploit cloned genes essential for silencing, endogenous silencing targets and silencing-related RNA products to characterise the action of host genes important for silencing and to identify a maximum number of plant genes involved in the different silencing mechanisms.

Deliverables

• Vectors and transformation protocols that produce transformants with a significantly reduced sensitivity to silencing.
• The molecular features of favourable genomic integration regions for transgenes that need to be stably expressed.
• Transgenic lines with a significantly-reduced potential for post-transcriptional gene silencing.
• Optimised transformation vectors for efficient gene silencing of homologous sequences.
• Technologies for inducible or tissue-specific gene silencing.
• Transgenic lines with an enhanced ability for gene silencing.
• A dissection of individual gene silencing mechanisms.
• A set of plants genes encoding individual functions in gene silencing pathways.
• A set of plants genes that are regulated by gene silencing mechanisms.

Contacts

Coordinator

• Peter MEYER / The University of Leeds Leeds Institute for Plant Biotechnology / UNITED KINGDOM

Participant

• Rudy DEKEYSER / Flanders Interuniversity Institute for Biotechnology VZW / BELGIUM
• Mary ANDERSON / J L DICKS / John Innes Centre Department of Applied Genetics / UNITED KINGDOM
• Max M. BURGER / Novartis Forschung Stiftung, SWITZERLAND
• Wim van OVERSCHOT / Novartis Seeds bv NETHERLANDS
• David ROBINSON / The University of Leeds Leeds Institute for Biotechnology and Agriculture / UNITED KINGDOM
• Antonio FANTONI / Universita' di Roma "La Sapienza" Dpto di Biotecnologie Cellulari ed Ematologia / ITALY
• Kate HUGHES / University of Nottingham School of Biological Sciences / UNITED KINGDOM
• J.G. van der ZEE / Vrije Universiteit Amsterdam Biology Faculty, Dept of Developmental Genetics / NETHERLANDS
• Baukje VRIESWIJK / Wageningen University Department of Plant Sciences / NETHERLANDS
• Marian FLATTERY / Zeneca Agrochemicals Jealott's Hill Research Station / UNITED KINGDOM
• Herbert MANG / Österreichische Adademie der Wissenschaften Plant Mol. Genetics, Inst. Mol. Biol. / AUSTRIA