A new perspective of zinc storage and biofortification: Unraveling the role of zinc binding properties of barley (Hordeum vulgare) grain storage proteins through transcriptomics and proteomics studies

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

  • Mohammad Nasir Uddin, Danmark
OriginalsprogEngelsk
ForlagAarhus University, Faculty of Science and Technology
Antal sider230
Rekvirerende organGraduate School of Science and Technology
StatusUdgivet - 24 mar. 2014

Note vedr. afhandling

Cereal grains are inherently contain less proteins and minerals than some legumes. In spite of this up to 75% of the daily calorie intake of the human beings living in the rural areas of the developing world comes from cereal-based foods with very low zinc (Zn) bioavailability and concentrations. In biological system Zn is commonly found bound to low molecular weight chelators (nicotianamine and phytochelatins) and their binding to proteins has been postulated but not exploited so far. Some reserve proteins known as ‘storage protein’ are highly abundant and could have a significant role not only for nutrient but as mineral deposition as well. However the majority of the previous research work on Zn biofortification were mainly focused on proteins that are less abundant in the grain (i.e., transporters, chelators etc ) whereas very little research was done regarding the potentiality of the highly abundant ‘storage proteins’ (such as hordein in barley endosperm) to serve also as Zn binding proteins.

During his PhD studies, Nasir Uddin conducted a series of experiments using molecular and biochemical techniques within transcriptomics and proteomics platform to increase the grain Zn content and suggested a way to improve protein quality/quantity of barley grain. Zn blotting assay was developed and applied for identification of Zn binding proteins from barley grain. Furthermore, Zn-IMAC chromatography followed by protein identification with mass spectrometry was performed for the characterization of the most abundant Zn binding proteins. In addition, Zn fertilization experiments were carried out followed by quantitative real time PCRfor gene expression studies in developing barley grain in order to understand the influence of Zn on barley hordeins, nicotianimine synthase, yellow stripe like transporters, catalase, glutathione-S-transferase, serpins and α-amylase inhibitors etc.

Results from those experiments suggested that some abundant barley storage proteins such as B-hordeins are capable of binding Zn or have role in Zn storage. Furthermore, a set of gene/protein was identified among cupin and prolamin super families which might function as Zn storage sink in the grain. In addition, the PhD project also suggested a link between Zn concentration and redox stages of S-rich major storage protein of barley grain. Moreover, some of the methods developed in this projects are novel and never been applied previously in barley. Therefore, the key findings from this project can be useful for the future Zn biofortification strategies as well as increasing protein quality /quantity of cereal grains.

The PhD degree was completed at the Department of Molecular Biology and Genetics, Science and Technology, Aarhus University.

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