Pod shatter resistance in oilseed rape through reduced gibberellin synthesis

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

Abstract

Yield of oilseed rape (Brassica napus) would be significantly enhanced by optimising specific aspects of fruit development such as control of seed dispersal (pod shatter). In the UK alone, losses due to pod shatter are estimated at ~£50M, and globally >£1B. We have used recent BBSRC funding to reveal that production of the plant hormone gibberellin (GA) as a requirement to define the cells that mediate pod shatter in Arabidopsis, a close relative of B. napus. We demonstrated that reducing GA production in these cells leads to inhibition of Arabidopsis fruit opening, thereby providing a promising strategy to reduce pod shatter in oilseed rape.
The focus of the project is to reduce gibberellin biosynthesis in the cells, which mediate oilseed rape fruit opening. The approach includes exploitation of induced sequence variation in GA4 genes of B. napus, which encode enzymes involved in the last step in the synthesis of bioactive GA.
Our main hypothesis for this project is that the GA4 genes are important regulators of shatter resistance in oilseed rape as it has been demonstrated in Arabidopsis. Here we will combine our results on the GA4 gene from Arabidopsis with the sequence information of four B. napus GA4 copies to isolate lines with mutations in these genes. To this end we will screen a B. napus TILLING population established at JIC. Allelic series of mutations in all four Brassica GA4 genes will be isolated and crosses between them initiated.
TILLING approaches to reduce Brassica pod shattering are non-GM, removing any problems with difficulties and expensive measures in marketing a GM-based product. Moreover, the traits would be stable throughout generations, which is particularly important to predictably obtain the optimised level of shatter resistance. This approach is expected to produce material for immediate use in backcrossing programmes into elite varieties, and efficient dissemination will be facilitated through close contact to breeding companies.

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