|Natarajan, Savithiry - Savi|
|Khan, Farooq - University Of Maryland|
|Cregan, Perry - Retired ARS Employee|
|Shipe, Emerson - Clemson University|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2016
Publication Date: 1/25/2016
Citation: Natarajan, S.S., Khan, F., Song, Q., Lakshman, S., Cregan, P., Scott, R.A., Shipe, E., Garrett, W.M. 2016. Characterization of soybean storage and allergen protein affected by environmental and genetic factors. Journal of Agricultural and Food Chemistry. 64(6):1433-1445.
Interpretive Summary: Soybean provides an economical source of protein for humans and animals. Different soybean varieties are grown in different geographic locations throughout the United States. These locations have different growing seasons, climates, and different soil compositions. To determine if the natural soybean seed protein profiles vary from cultivar to cultivar, from location to location, and from season to season, we characterized soybean seed proteins from three states, MD, SC, and SD. In addition, we compared seed proteins across genotypes and environments to observe any relationships. We found higher significant differences in the expression of proteins with respect to environmental factors compared to genetic factors. These results are important for the evaluation of soybean seed production and will be of interest to soybean growers, breeders, and producers at universities, government agencies, and private industry.
Technical Abstract: Knowledge of the impact of genetic variability and diverse environments on the protein composition of crop seed is of value for the comparative safety assessments in the development of genetically engineered (GMO) crops. The objective of this study was to determine the role of genotype (G), environments (E) in terms of two sowing dates, and the interrelationship of genotype and environment (GxE) on soybean seed protein. The investigation considers specifically the storage and allergen protein in soybean seed. Three sets of nine diverse soybean and wild soybean genotypes were selected with appropriate photoperiod adaption and grown in replicated trials at three geographically distinct field sites in the US, namely Maryland (Beltsville, MD), South Carolina (Clemson, SC), and South Dakota (Brookings, SD). At each location, the nine genotypes were grown with two planting/sowing dates designated as “early” and “late”. A combined proteomics approach, including two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) for protein separation and mass spectrometry (MS) for protein characterization, was applied to study the variability of two major storage proteins (ß-conglycinin and glycinin) and allergen proteins (P34, SAM 22, 2S albumin and Gly m Bd 28 K) in the soybean seed. The total number of storage and allergen protein spots characterized in the soybean seeds was 47 and 8, respectively. Statistical analysis of the protein expression data in terms of differentially expressed protein spots significant at the p<0.005 level was performed for early and late sowing dates at each site and across all three locations. We found more spots that showed significant differences in expression among sowing dates (E) compared to genotype (G) and GxE interaction. Similarly, based on the component analysis, more spots of storage and allergen proteins showed significant differences in expression associated with environmental factors (E) than with genotype (G), and genotypic and environmental interaction (GxE) in all samples collected from MD, SC, and SD. These results are of importance for the evaluation of genetically modified soybean genotypes to determine if such genotypes produce seed with storage and allergen proteins that fall outside the range of non-GMO soybean genotypes.