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Manipulation of Transfer Cells to Improve Grain Filling


The modification of a cell for a transfer function is a phenomenon widespread in plant development and underscores some of the major differentiation processes which take place. In addition to their localization in the vascular system, transfer cells are found in the suspensor, which is a vital component of early embryo development, at the sporopytee/megagametophyte junction, where they promote solute partitioning to the developing seed, and at the sites of interaction with other organisms, for example in nematode cysts. Despite their wide distribution, the biogenesis of transfer cells, and their quantitative contribution to solute partitioning have still to be investigated. Recent progress in Europe, including the isolation of transfer cell-specific markers, the manipulation of partitioning by transgene expression, and the refinement of physical and immunological techniques for analysing steps in cell differentiation promise to provide a wealth of information, needed to make rational improvements by manipulating plant crop plant physiology, and specifically to permit the expression of enzymes and other value-added proteins in this seed compartment. The present proposal brings together leading EU specialists on transfer cells, and the analytical techniques required for understanding their function and exploitation.
The Biotechnology Workplan identified a number of areas of plant research with serious defects in basic knowledge: cell transport and partitioning, sink/source relationships, and the differentiation of intercellular matrixes. This proposal, which is divided into 4 work packages WP 1 to 4, will make a focussed contribution to these topics.
WP 1, the identification of promoter elements necessary to confer transfer cell-specific expression is an essential pre-requisite to improving solute partitioning by transgenic intervention. A specific research task set out in the Workplan is the understanding of sinksource relationships to optimize crop yield (3.1.2), which is approached by the second work package (WP2), in which the contribution of transfer cells to solute partitioning will be assessed in transgenic plants overexpressing invertase. This project also incorporates a study of the role of gametic imprinting in the seed transfer layer development (WP 1.4), as this contributes a major regulatory component of endosperm gene expression. In WP3, alternate strategies for increasing the efficiency of solute partitioning are to be explored. In WP4, the characterization of the function of two transfer cell-specific proteins, BETL- 1 and BETL-2 is planned. Here we aim to determine the contribution of these proteins to facilitating solute transfer, making this study an integral part of the overall strategy. The application of this area of expertise relies on the participation in this project of a laboratory in possession of the most recent cereal transformation technology. Thus, the role played by AgrEvo in this project, who will provide this facility, will be vital. AgrEvo also has the necessary infrastructure and relevant experience to take up commercially viable products of this research.. The need of EU farmers to increase agricultural competitiveness puts new demands on plant breeders and bio-technologists. Basic research can make a contribution in this area most effectively if a relevant target area is identified and an application-driven project is developed. The present proposal represents such a focus, and will therefore be able to provide transgenic material modified for characters of agronomic interest, and the technical know-how for further crop improvement.

Funding Scheme

CSC - Cost-sharing contracts


Max-Planck-Gesellschaft zur Förderungder Wissenschaften e.V.
50829 Köln

Participants (4)


65926 Frankfurt
United Kingdom
South Parks Road
OX1 3RB Oxford
S/n,campus Universitario. Ctra Nii, Km 33
28871 Alcala De Henares
Università degli Studi di Siena
Via P. A. Mattioli 4
53100 Siena