FAIR-CT96-3072 Engineering shatter resistance into oilseed rape

Contacts




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Biotechnology : FAIR Area 3 - Generic Science and Advanced Technologies for Nutritious Foods : Plant Genetics : Vegetable Oil/Fat

	Proposal No:	FAIR-CT96-3072
	Date Prepared:	January 1998
	Source:	Proposal Abstract

Abstract:
The goal of this project is the production of transformed plants of oilseed rape that are resistant to pod shatter. Shatter refers to pod opening and seed dispersal before harvest leading to loss of yield. The incidence of rape as a weed in subsequent seasons leads to the need for adaptation of harvesting procedures to reduce loss of quantity and quality of the seeds. Increased resistance to opening will reduce from fully mature pods and reduce the proportion of immature seeds at harvest. Increased seed recovery and lower refining costs will increase production efficiency and oil quality. We have obtained a detailed understanding of the mechanisms underlying pod opening and have identified three engineering strategies for which the relevant genes have been identified and are available.

The strategies are:

• Inhibition of middle lamella breakdown of cells in the pod dehiscence zone (where the pod opens) - At pod maturity, depolymerization of pectin is confined to the middle lamella of cells in the dehiscence zone. A gene encoding for a tissue-specific polygalacturonase (PG) responsible pectin degradation has been identified and cloned. The expression of the PG and another cell wall degrading enzyme, cellulase will be suppressed by antisense down-regulation under the control of the dehiscence zone-specific promoter
• Interception of hormone signals affecting cell breakdown in the pod dehiscence zone. We have shown that sustained auxin levels in the pod delays cell separation and significantly increases the energy required to open the pods. We will sustain auxin in transformed plants by introducing prokaryotic genes for auxin biosynthesis in oilseed rape under the control of the PG promoter.
• Inhibition of cell activity in the dehiscence zone. Controlled expression of an RNAse (barnase) following differentiation of the pod tissues will be used to prevent further development and cell activity in the dehiscence zone.

A major part of the project will be devoted to the characterisation of the transgenic lines. The screening will be carried out on glasshouse and field grown plants and will involve characterisation at the biochemical, anatomical and biophysical levels. At the end of the project, transgenic lines carrying genes resulting from single or combined approaches will be available for more extensive evaluation in a breeding programme.

Contacts

Coordinator

• Dr Peter ULUSKOV / Danish Inst of Agricultural Sciences Min of Food Agriculture & Fisheries / DENMARK