Norwegian wheat with optimized protein content and high baking quality

Wheat produced in Norway has often varying gluten functionality and lower protein content than is requested from the milling- and baking industry. These quality changes has become more prominent due to unfavorable weather in recent years. The QualityWheat project was launched to improve these quality traits with the overall aim to increase the use of Norwegian wheat for milling, and thereby contribute to the national goals of increased food production. The project had following activities; 1) study the main factors giving variation in gluten quality including pathogenic fungi (Fusarium spp. and Microdochium spp.), 2) study how N-sensor technology to improve nitrogen fertilization practice can increase protein content, and 3) yearly assessment of gluten quality of the new wheat harvest and to disseminate the results to the industry. Earlier results indicated the association between fungal infection and reduced gluten quality. In this project, wheat samples from field trials having good and poor quality were analyzed for the composition of microorganisms (using Metabarcoding and qPCR). The common fungal pathogens, Microdochium spp. and Fusarium spp., were much more prevalent in samples with poor gluten quality. We showed that these fungi could grow on media with gluten proteins as the only nitrogen (N) source, indicating that they degrade gluten proteins and use them as their nutrient source. Grain from Fusarium graminearum inoculated plants displayed very active proteases that could degrade gluten proteins. By using Proteomics, 40 fungal proteases were identified in inoculated grain samples and 15 of these were presumed to degrade gluten proteins. Moreover, F. graminearum infestation critically reduced the synthesis and build-up of gluten proteins, which are crucial for breadmaking. Even small amounts of fungal infected sample in flour blends considerably reduced the gluten functionality during the breadmaking process. Thus, our study showed that infection by fungi within the Fusarium and Microdochium genera could cause poor gluten quality by secreting proteases that degrade gluten proteins in developing grain as well as during the breadmaking process. Moreover, our results showed that rain during grain maturation could interfere with gluten protein build-up. Such weather conditions also promoted fungal infection and growth, which could lead to an increase in gluten-degrading proteases in grain. To investigate the possible use of the N-sensor to increase protein content and reduce within-field variations, field experiments were carried out and site-specific N fertilization using Yara N-sensor were compared with fixed rate (applied at the flag-leaf stage). Site-specific fertilization using the N-sensor reduced within-field variation in protein content, grain maturity and yield. Moreover, we established a simple model for pre-harvest estimation of protein content based on the data collected by N-sensor at the flowering stage. This modeling approach could be used to delimitate protein targeted harvesting zones based on the predicted protein content. Targeted harvesting may increase protein content and reduce the within-batch variation. Field trials were also conducted to study effects of late N application regimes on protein content and gluten functionality. Extensibility of gluten increased with increasing protein contents due to late N application, while elasticity was not significantly affected. This study, performed with strong wheat varieties, showed that late N fertilization efficiently increased protein content without decreasing the gluten quality, and thereby contributed to an overall improved breadmaking quality. The project has assessed gluten quality of the new harvest, and performed yearly quality predictions that were disseminated and discussed with the industry partners. The quality prognosis has been used by the industry partners to achieve better utilization of the Norwegian wheat and for planning of import. This activity has been important for the whole value chain, and should be continued. Overall, the project has made important progress to understand factors causing poor bread-making quality. Particularly, we gained an important knowledge of gluten-degrading proteases which could be found in grain infested by fungi. Such proteases could severely reduce gluten functionally by degrading gluten proteins during grain development and breadmaking process. Our studies showed that rain during grain desiccation could have adverse effects on breadmaking quality. The knowledge enable us to develop measures to reduce the problem. Finally, the project demonstrated that N-sensor technology is a potential tool to assist farmers to produce wheat with optimal protein content.

Virkninger: 1) Kompetanseoppbygging hos forskningsinstitusjonene 2) Styrket og utvidet samarbeid innen hveteforskningen 3) Kompetanseoverføringer mellom partnere i Konsortiet 4) Karriereutvikling for to postdoc. Bidratt til utdanning av masterstudenter. 5) Kartlegging av årets hvetekvalitet har hatt direkte nytteverdi for brukere. Effekter: 1) Resultatene har gitt grunnlag for å stille mer presise hypoteser for videre forskning. Tilpasning av nye analyseverktøy vil åpne nye muligheter innen forskning. Potensielle virkninger: 1) Prosjektet har gitt grunnlag for å analysere genetisk variasjon i stabilitet av glutenkvalitet med sikte på å foredle nye sorter. 2) Utvikle effektive tiltak i verdikjeden som reduserer variasjonene i glutenkvalitet Potensielle effekter: 1) Forbedret kvalitet og bedre utnyttelse av norsk mathvete i verdikjeden, som vil bidra til økt norsk matproduksjon.

The proportion of Norwegian wheat in the flour has been strongly reduced in later seasons, due to both lower wheat production and poor baking quality. Growth conditions, with wet and cool weather during grain development and ripening, provide new challeng es for the production of quality wheat. The present project focus on how to secure optimal and stable protein content and functionality of gluten, parameters of major importance for the baking quality. The primary goal is to provide higher quality and bet ter utilization of Norwegian wheat, to meet the national goals of increased food production. Within this project we intend to: Provide yearly prognoses of the wheat quality for use by the industry in their planning and utilization of the Norwegian wheat ( WP1); Investigate new technology as site-specific fertilization and targeted harvesting, to achieve more optimal and stable protein content in wheat (WP2); Identify Fusarium spp. or other microorganisms associated with poor functionality of gluten (WP3); Identify proteases causing degradation of gluten proteins, as well as protease inhibitors in wheat (WP4). The knowledge developed within this project enables a future development of targeted control measures to secure good gluten functionality. On the far mers level, knowledge on how to achieve optimal and stable protein content with the use of site-specific fertilization and targeted harvesting will improve farmer profits and secure a higher percentage of high quality wheat. Knowledge on proteases associa ted with poor baking quality in wheat may be utilized in future breeding to identify relevant protease inhibitors in wheat. The project will build new competence, particularly in the interface between gluten functionality and effects of Fusarium/microorga nism infestations, and on new technologies within precision farming to achieve optimal protein content. The project will generate important knowledge valid for Norwegian, as well as international wheat production.