A bread wheat biofortification project - physiologycal and molecular characterization of grain filling

Considering that a goal of biofortification is to develop genotypes that have an increased content of bioavailable nutrients in their edible parts, the production and mobilization of photoassimilates to the seeds might be understood as a key issue. This study aims at to design a physiological and molecular model to further understand the metabolic pathways of grain filling driven by photosynthesis. Thus, during the vegetative growth of genotype with high potential to biofortification in Zn, the kinetics of leaf gas exchange (mainly, leaf stomatal conductance, net photosynthesis and photosynthetic capacity) and chlorophyll a fluorescence (to evaluate the impact on the capture, use and dissipation of the collected light energy: Fo, Fv/Fm, Fv'/Fm', fe, qP, qN and NPQ) will be measured and related with the patterns of nutrient accumulation in the grain at the end of the reproductive process. In this process, to access the change in Zn level between wheat genotypes, the patterns of gene transcription and the abundance of proteins involved in transport and storage will also be determined by biochemical and molecular tools (through the transcriptional analysis of a set of genes involved in Zn metabolism, mostly in transport and storage, complemented by Western blot studies).