Kwang-Hyun Shin

Large-scale proteome investigation in wild relatives (A, B, and D genomes) of wheat

Large-scale proteomics of three wild relatives of wheat grain (A, B, and D genomes) were analyzed by using multidimensional protein identification technology coupled to liquid chromatography quadruple mass spectrometry. A total of 1568 (peptide match ≥1) and 255 (peptide match ≥2) unique proteins were detected and classified, which represents the most wide-ranging proteomic exploitation to date. The development of standard proteomes exhibiting all of the proteins involved in normal physiology will facilitate the delineation of disease/defense, metabolism, energy metabolism, and protein synthesis. A relative proteome exploration of the expression patterns indicates that proteins are involved in abiotic and biotic stress. Functional category analysis indicates that these differentially expressed proteins are mainly involved in disease/defense (15.38%, 21.26%, and 16.78%), metabolism (8.39%, 12.07%, and 14.09%), energy metabolism (11.19%, 11.49%, and 13.42%), protein synthesis (9.09%, 9.20%, and 8.72%), cell growth and division (9.09%, 4.60%, and 6.04%), cellular organization (4.20%, 5.75%, and 5.37%), development (6.29%, 2.87%, 3.36%), folding and stability (6.29%, 8.62%, and 8.05%), signal transduction (11.19%, 7.47%, and 8.05%), storage protein (4.20%, 1.72%, and 2.01%), transcription (5.59%, 5.17%, and 4.03%), and transport facilitation (1.40%, 1.15%, and 3.36%) in A, B, and D genomes, respectively. Here, we reported genome-specific protein interaction network using Cytoscape software, which provides further insight into the molecular functions and mechanism of biochemical pathways. We provide a promising understanding about the expressed proteins and protein functions. Our approach should be applicable as a marker to assist in breeding or gene transfer for quality and stress research of cultivated wheat.

Diversity of Novel Glutenin Subunits in Bread Wheat (Triticum aestivum L.)

Glutenin is a major determinant of baking performance and viscoelasticity, which are responsible for high-quality bread with a light porous crumb structure of a well-leavened loaf. We analyzed the diversity of glutenin genes from six wheat cultivars (Korean cvs. Keumgang and Jinpum, Chinese cvs. China-108 and Yeonnon-78, and Japanese cvs. Norin-61 and Kantou-107). Glutenins contain two types of isoforms such as high molecular weight glutenin subunit (HMW-GS) and low molecular weight glutenin subunit (LMW-GS). Glutenin fractions were extracted from wheat endosperm using Osborne solubility method. A total of 217 protein spots were separated on two-dimensional gel electrophoresis with isoelectric focusing (wide range of pH 3–10). The proteins spots were subjected to tryptic digestion and identified by matrix assisted laser desorption/ionization–time of flight mass spectrometry. HMW-GS (43 isoforms) and LMW-GS (seven isoforms) are directly responsible for producing high-quality bread and noodles. Likewise, all the seed storage proteins are digested to provide nutrients for the embryo during seed germination and seedling growth. We identified the diverse glutenin subunits in wheat cultivars and compared the gluten isoforms among different wheat cultivars according to quality. This work gives an insight on the quality improvement in wheat crop.

Wild Relatives of the Wheat Grain Proteome

We applied proteomics analysis to generate a map of the wild relatives of wheat grain proteins. These differentially expressed proteins are potentially involved in metabolism, stress responses, and other biological activities. Using two-dimensional electrophoresis, we detected 119, 134, and 193 reproducible spots on gels loaded with protein samples extracted from the A, B, and D genomes, respectively, of the mature grain. In all, 89, 53, and 54 distinct proteins, respectively, were found among these genomes through MALDI-TOF mass spectrometry. Of these, 26% (n = 52) proteins were considered distinct. They included 18.89% (n = 17) in the A, 28.30% (n = 15) in the B, and 37.04% (n = 20) in the D genome, all functioning in disease and defense roles. For example, the ABA-inducible protein PHVA1 can be induced by drought, cold, heat, and salinity, while the basic endochitinase confers protection against chitin-containing fungal pathogens. The diverse functional categories found here suggest different biological processes, such as disease/defense, energy metabolism, protein synthesis and storage, cellular organization, signal transduction, transcription, and the facilitation of transport. Our findings demonstrate that these functional proteins have important roles in stress tolerance and the maintenance of quality in mature grains. The interacting effects of genetics and environment on differential protein production may be partially mediated by a regulatory mechanism in those grains.