Auxin as a key regulator of pod shatter in Arabidopsis and Brassica

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

Abstract

Arabidopsis fruit are typical of fruit from the greater than 3000 species of the Brassicaceae family and develop from the female reproductive tissue, the gynoecium. After fertilisation, patterning genes divide the developing fruit into three main parts: The valves, the replum, and the valve margins that form at the valve/replum border. At the valve margin a narrow file of dehiscence zone cells differentiates along the entire length of the fruit late in development, allowing the valves to detach from the replum and seed dispersal to occur by a mechanism called pod shatter. Recent results from our group have shown that the plant hormone, auxin, is a major player in regulating tissue formation in Arabidopsis fruit. Our results indicate that local tissue-specific changes in auxin concentration controls pod shatter. Here we will investigate the role of auxin in fruit development further by driving the expression of auxin-modifying genes in various tissues of the fruit and by revealing how the flow of auxin is regulated during Arabidopsis fruit development. Brassica species are closely related to Arabidopsis and represent ideal candidates for model-to-crop approaches as they include important crop plants such as oilseed rape. Brassica plants also disperse their seed by pod shatter. Although this mechanism is an advantage in nature, unsynchronised pod shatter constitutes one of the biggest problems for oilseed rape farmers. Despite a remarkable size difference, the overall shape of Arabidopsis and Brassica fruit are highly similar suggesting that strategies to modify pod shatter in Arabidopsis may be readily transferable into various Brassicas. Here we will use knowledge from Arabidopsis on the role of auxin in fruit patterning to regulate specification of Brassica fruit tissues. This approach should allow us to develop distinct strategies for controlling pod shatter in Brassica with benefits for the UK economic competitiveness, farmers, the public and the environment.

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