Unravelling the role of endosperm proteins for zinc loading into the cereal grain

Understanding the accumulation and distribution of essential nutrients, including zinc (Zn), in cereals is of primary importance for improving the health of people around the world. While recent studies have improved our knowledge of the genetic basis for Zn transport, the binding forms of Zn in wheat grain and the role of various Zn-binding ligands for Zn loading into various wheat grain compartments are poorly documented.

 

In my Ph.D. project I contributed with novel information on Zn compartmentalisation, binding and biofortification (Persson et al., 2009; Lee et al. 2009; Hansen et al. 2009). It was concluded that proteins rather than phytate are important for Zn storage in barley. In the present project, the identity of the dominating Zn binding proteins in the wheat endosperm will be elucidated, using the most powerful state-of-the-art separation methods in combination with the superior elemental sensitivity of inductively coupled plasma - mass spectrometry (ICP-MS).

 

Using stable Zn isotopes, the Zn speciation1 work will be coupled with studies of the physiological regulation of Zn loading into the grain during the grain filling period. The project will create novel and powerful synergy between plant physiology, metallomics and proteomics, which will facilitate plant breeding and fertilization strategies aiming at alleviating the acute lack of Zn in cereal-based foods.

 

The following 3 hypotheses will be tested:

 

1. Loading of Zn into the wheat endosperm occurs during a relatively narrow time window during which Zn derived from re-mobilization or foliar application is critical for the final Zn concentration of the endosperm.
2. Zn storage in the wheat endosperm is controlled by gluten proteins and is thus affected by N supply
3. Zn influences the composition of the proteins in the endosperm during grain filling and at maturity

 

Project description (PDF)

 

Results (PDF)

 

Project plan (PDF)

 

 

For further information please contact Postdoc Daniel Olof Persson