Dynamic and evolution of cis-regulatory elements involved in fruit development in Arabidopsis and Brassica

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

Abstract

Despite the growing number of transcription factors that play a role in fruit patterning in Arabidopsis, little is known about the molecular interactions that control this fundamental process for plant reproduction. This project focuses on genes and interactions that are relevant for fruit dehiscence. One of these key genes is REPLUMLESS (RPL) which is required for the development of a specialized structure, the replum, involved in the opening process of the fruit to release seeds. RPL functions in part by restricting the expression of SHATTERPROOF (SHP1 and 2), which specify valve margins (another specialized tissue type that surrounds the replum), and JAGGED (JAG), which promotes SHP gene expression. Although closely related, Brassica and Arabidopsis fruits show differences in replum development. Whereas the Arabidopsis replum is about 10 cell files wide, Brassica replum often only consists of 1-2 cell files. This phenotype mimics the phenotype of a weak rpl mutant in Arabidopsis , therefore a further reduction of the replum size in Brassica could give rise to shatter-resistant fruit that would benefit the oilseed rape industry. Our broad goals are to understand whether regulatory changes in RPL, JAG and SHP explain differences in fruit development between Arabidopsis and Brassica, and how further changes could be used to limit pod-shattering in Brassica. We will compare the regulatory sequences of these genes in different species, define ciselements that mediate the interactions within this regulatory network, test the functional significance of these cis-elements in transgenic plants, then use TILLING to screen for regulatory changes in Brassica. Bridging our knowledge from Arabidopsis to Brassica would give us a great opportunity to study how variations in the regulatory network might generate the subtle differences between the fruits of both species and would have practical applications for reducing seed loss due to pod shattering in Brassica

Publications

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Description We discovered that the plant hormone gibberellin controls the development of fruit tissues required for seed dispersal. This opens possibilities to control loss of seeds due to premature opening of the pods of oilseed rape. Based on this finding, an international patent was filed and granted.

1. We discovered that the plant hormone gibberellin controls the development of fruit tissues required for seed dispersal.

2. We revealed that fruit structures involved in seed dispersal have been modified by similar mutations during rice domestication (shown by others) and during the evolution of plants of the oilseed rape family (our results). This was an important contribution to a long-standing debate whether domestication and evolution are based on the same types of genetic change.
Exploitation Route The findings may hep to develop new genetic tools to control pod shattering in rapeseed.
Sectors Agriculture, Food and Drink

 
Title CONTROL OF PLANT SEED SHATTERING 
Description The invention provides methods and materials for modifying tissue dehiscence in a plant such as to modify seed release therefrom, The invention generally comprises modifying the plant by either: (i) altering the expression of a nucleic acid encoding a target enzyme, which target enzyme is responsible for either biosynthesis or degradation or inactivation of gibberellins (GAs) in the tissue such as to alter the level of GAs in the tissue, or (ii) altering expression of a nucleic acid encoding DELLA or an analog (for example which is degradation resistant) thereof in the tissue such as to alter the amount of said DELLA or DELLA analog in the tissue. By modifying the levels of active GAs in the plant the invention permits the fine-tuning of the seed dispersal process. For example reducing the levels of active GAs can be used to reduce or delay seed shattering. 
IP Reference WO2011157976 
Protection Patent granted
Year Protection Granted 2011
Licensed No
Impact None yet