Exploring knowledge of gene function to combat pod shatter in oilseed rape

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office

Abstract

The aim of this project is to introduce pod shatter resistance into modern oilseed rape varieties by modification of two paralogous genes. We have previously described how the INDEHISCENT (IND) gene regulates shattering in the model plant Arabidopsis and how this knowledge can be transferred to Brassica species such as B. rapa and B. oleracea. Here, resistant lines will be identified via TILLING (Targeting Induced Local Lesions IN Genomes) for mutations in the two B. napus IND genes. Single and double mutants will be characterised for their ability to fine-tune the shattering process and will be backcrossed to elite varieties for immediate use in breeding programmes. In addition to the significant commercial and environmental value of such lines, the experiments that we have planned will expand our knowledge on the molecular mechanism by which IND mediates its function. To this end, we will take advantage of a large allelic series of point mutations in the IND gene in B. rapa (BraA.IND). IND regulates hormone balance at the valve margin, and the mutant lines will be tested for their ability to create an auxin minimum and direct expression of the GA biosynthesis gene GA4. We have previously shown that IND can form homodimers in yeast and heterodimers with a related transcription factor, SPATULA. We will create site-directed mutants in the BraA.IND gene corresponding to those identified in the allelic series to map the domains required for these protein-protein interactions. In this way, the proposed project will drastically reduce and possibly eliminate pod shatter in oilseed rape and will advance our knowledge on fruit tissue-specification while developing tools for further fine-tuning of pod shatter resistance in future varieties.

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