Partenaires et organisations internationales
(Anglais)
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Europäisches Konsortium (D, E, F, GB, NI, P)
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Résumé des résultats (Abstract)
(Anglais)
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Phosphate (Pi) efficiency is of crucial importance for the growth and development of plants and a key component of the genetic yield potential of crops. Most soils under agricultural exploitation are low in Pi availability. Even in Pi rich soils, for example in central Europe, most of the Pi is present in an immobile form and therefore is not readily available for the plant. In this EU project a multidisciplinary approach is followed to devise means to genetically engineer plants in order to improve Pi efficiency and optimise carbon allocation towards storage organs. The vertically integrated approach on the whole plant level will enable the development of new technologies for crop improvement.
In contrast to the crucial importance of Pi for plant growth and development very little is known about the mechanisms which influence Pi-efficiency on the whole plant as well as on the cellular and molecular levels. The same holds true for the root system, which is an indispensable source for mineral nutrients.
Our group at the Institute of Plant Sciences, ETH Zurich, is studying the molecular and biochemical processes involved in Pi acquisition at the root/soil interface (Bucher et al., 2001).
Genes which are predominantly expressed in rhizodermal cells have been characterised (Bucher et al., 1997) and the regulation of expression of one of these genes has been investigated (Bucher et al., submitted).
Since the root hairs are the first cells to get into contact with Pi from the soil, we believe that these cells carry all prerequisits for efficient Pi acquisition. To unravel these mechanisms, we analyse Pi-directed gene expression in root hairs in a second part of our work.
The first step in Pi biology is its uptake in living root cells. This is mediated by Pi transporter proteins in the plasma membrane of the rhizodermal cells (Raghothama, 1999; Raghothama et al., 1999; Daram et al., 1998). After entry in the root, Pi is translocated within the plant, e.g. to leaves, flowers or seeds, due to the concerted action of other transport systems. We have characterized a Pi transporter, which is expressed in the shoot and belongs to a novel family of plant transporter proteins (Daram et al., 1999).
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