Agnieszka Kaczmarczyk: Multi-method research strategy for understanding changes in storage protein composition in developing barley grain to improve nutritional profile

Barley is cultivated in a range of diverse environments and is widely utilised as feed for animals and as malt in brewing. Hordeins, the main storage proteins of barley grain, highly influence feeding and malting quality. Nitrogen (N) is a key macronutrient which directly increases plant growth and is used as a fertiliser to meet the demands for higher yield. However, the increases in the nitrogen fertiliser are not accompanied by a good quality of protein composition in barley. The high N-dosage promotes C-hordein synthesis, the class with the lowest content of essential amino acids (AAs) and the highest content of non-essential AAs. 
During her studies, Agnieszka undertook multi-method research approach to get a detailed insight into synthesis of storage protein of field grown barley grain in relation to different nitrogen regimes. She developed a new rapid quantitative PCR platform to follow gene expression levels of hordein families. Using this novel method, Agnieszka studied hordein gene expression in the developing field grown barley grain under low, normal and high N rates. Furthermore, the same material was used for protein accumulation studies (2D-difference gel electrophoresis and mass spectrometry) and the estimation of AAs levels. The results showed that the synthesis of barley storage proteins is differentially affected by time, nitrogen treatment and the interaction of the two factors named TxN (time and nitrogen) and it was possible to correlate gene expression, protein level and AA composition in members of multigene families. 
The novel validated methods and findings can be a good assistance in breeding selectively to change AA composition by changing the relative proportions of the storage proteins in order to improve barley nutritional profile.

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

Time: Monday, 29 April 2013 at 13.00
Place: The lecture theatre, AU Flakkebjerg, Forsøgsvej 1, 4200 Slagelse
Title of dissertation: Multi-method research strategy for understanding changes in storage protein composition in developing barley grain to improve nutritional profile
Contact information: Agnieszka Kaczmarczyk, e-mail: Agnieszka.Kaczmarczyk@agrsci.dk
Members of the assessment committee:
Associate Director at Rothamsted Research, Professor, Peter R. Shewry, Plant Biology and Crop Science, Rothamsted Research, UK
Professor Emeritus Steven E. Ullrich, Department of Crop and Soil Sciences, Washington State University, USA
Professor Bo Thomsen (chair), Department of Molecular Biology and Genetics, Aarhus University, DK
Main supervisor:
Associate Professor Eva Vincze, Department of Molecular Biology and Genetics, Aarhus University, DK
Language: The PhD dissertation will be defended in English.

The defence is public.
The dissertation is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1521, room 112, 8000 Aarhus C.