Evaluation of Cell Wall Biosynthetic Genes in Hollow- and Solid-Stemmed Genotypes of Wheat (Triticum aestivum)

Cereal grains, including wheat, have immense potential to improve human health and to considerably lower the risk of serious diet-related diseases thanks to their micronutrients and relatively high fiber contents, while at the same time serving as a principal source of energy. In whole grain cereal, dietary fibers are made up of indigestible cell wall components; a complex of carbohydrates that include oligosaccharides, resistant starch and non-starch polysaccharides that are not digested by the enzymes of the small intestine in humans. Wheat production is hampered by a variety of pests, including sawfly, Cephus cinctus, a pest that causes lodging by burrowing into wheat stem leading to significant yield loss. Wheat cultivars having stems with solid piths, unlike their hollow-stemmed counterparts, are resistant to sawfly. We hypothesized that there are structural differences in the cell wall of hollow- and solid-stemmed genotypes of wheat and therefore anticipate identifying polymorphism in the genes that are involved in their synthesis. In order to investigate this hypothesis, wheat near isogenic lines (NILs), having 97% similarity in their genetic makeup (except for the solid stem loci), and their parental lines were grown in the green house and the tissue harvested for DNA isolation. PCR primers were designed from cell wall biosynthetic genes either from rice or wheat ESTs. Contrary to our hypothesis, data from PCR analysis showed largely monomorphic PCR products, suggesting that the cell wall genes are present in both the hollow- and solid-stemmed genotypes for all the cell wall genes evaluated. We are now beginning to assess the expression levels of these genes using qRT-PCR in an effort to see if there are differential expressions of the cell wall biosynthetic genes in these genotypes. The ultimate goal for this project is to identify useful solid stem genes that can be introgressed into elite wheat germplasms having the hollow-stemmed phenotypes. Funding: Funding support from the USDA-NIFA Triticeae Coordinated Agricultural Project (T-CAP) awarded CB and also by the U.S. Department of Education Award Number P382A110049 award to CB through CSER (Center for STEM Education & Research), Chicago State University.