2010 Annual Report
1a.Objectives (from AD-416)
Genetically improve wheat and other cereals for endosperm texture, Asian noodle color, carbohydrate composition, and develop new methods to evaluate end-product quality. Define genetic basis of desirable quality of Asian foods. Facilitate research on improving western wheats for domestic and Asian food product quality.
1b.Approach (from AD-416)
Determine the molecular and genetic basis of wheat grain texture by assessing puroindoline gene structure. Determine the effect of two different hardness alleles on grain texture, milling performance and baking quality. Assess the molecular genetic basis of discoloration in Asian noodles by identifying and characterizing polyphenoloxidase from wheat. Develop or adapt methods to evaluate wheat end-use quality with an emphasis on early generation testing. Employ gene expression measurement technology to identify genes contributing to desirable Asian food characteristics. Replaces 5348-43440-004-00D. 09/2009.
Most notable was the culmination of decades of work resulting in the creation of soft-kernel durum wheat through the non-GMO transfer of genes from bread wheat. These same genes were introduced into maize where they softened the kernel, thereby improving wet milling yields, and increased the oil content of the germ. Considerable progress was accomplished on identifying the genes, mechanisms and constituents of end-product quality of wheat grain. These include new information on the genes that make the wheat kernel soft or hard, enzymes that discolor some foods, and the lipid composition and protein content of wheat grain. All of this work aims at improving the processing and end-use quality of wheat and other cereals, thereby making food healthier and more affordable, while contributing to the sustainability of farms, rural communities, processors and food manufacturers.
The basis for kernel hardness in wheat. Genetic control of kernel texture is a primary consideration in milling and baking quality. ARS scientists in Pullman, Washington, in cooperation with a scientist with the Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, National Wheat Improvement Center, CAAS mapped a new variant of the puroindoline genes responsible for kernel softness. The genes were mapped to the three group 7 chromosomes. These genes may have a secondary role in kernel softness in wheat, and therefore plant breeders could use them to genetically improve milling and baking quality for these industries and consumers.
A novel grain protein gene in wheat. Protein content of wheat is important for nutrition and for gluten development, hence baking quality. ARS scientists in Pullman, Washington, in cooperation with University of California Davis and North Dakota State University scientists ascertained the effect of a novel grain protein gene in wheat. The gene improves nutrition and baking but often decreased grain and milling quality. Wheat breeders will need to consider background effects before using this gene since it can be deleterious; therefore its impact could be both positive and negative on wheat quality.
The basis for kernel hardness in wheat. Kernel texture affects milling performance and flour quality; different puroindoline alleles confer different levels of kernel texture. ARS scientists in Pullman, Washington, in cooperation with scientists at the Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, National Wheat Improvement Center, CAAS characterized an important hardness allele in wheat and developed a molecular marker for it. The Pina-D1b allele is very important for wheat breeding and improvement as it contributes to an especially hard texture. Wheat breeders can use the marker to detect the allele; thereby positively impacting wheat grain quality (milling and baking).
Wheat starch lipids. Lipids play a direct role in flour quality and baking performance. ARS scientists in Pullman, Washington, in cooperation with scientists at Kansas State University and Montana State University characterized the polar lipids on the surface of isolated wheat starch. Starch surface lipids may affect baking properties and food quality. Starch from soft wheat was found to have a much greater abundance of polar lipids compared to starch from hard; the method of starch isolation was also found to affect lipid presence. The reason for differences in starch surface lipids is not full known, the results will guide future research strategies.
Wheat lipids and grain hardness. Lipids play a direct role in flour quality and baking performance. ARS scientists in Pullman, Washington, in cooperation with scientists at Kansas State University and Montana State University characterized the polar lipids among near-isogenic hard and soft wheat. The basis for kernel texture is not fully known nor is the effect it has on flour polar lipids. Polar lipids from whole grain meal, flour and isolated starch were characterized from near-isogenic hard and soft wheat. Meals did not differ in polar lipids, flours differed only slightly but polar lipids isolated starch were dramatically lower in hard compared to soft wheat starch. These results add to our understanding of how kernel texture in wheat affects quality.
Maize milling yields. Extraction of starch during wet milling is a primary economic consideration. ARS scientists in Pullman, Washington in cooperation with scientists at Montana State University in Bozeman, Montana, ascertained the effect of wheat puroindoline proteins in the endosperm of maize. The presence of the puroindoline gene expression caused an improvement in wet milling yields. Use of the transgene in maize must be approved before it can be used in the food production system. Increased milling yields would translate into more efficient utilization by the food industry.
5.Significant Activities that Support Special Target Populations
SCEP employee/student at Washington State University is enrolled in the organic ag/sustainable agriculture program.
Brevis, J.C., Morris, C.F., Manthey, F., Dubcovsky, J. 2010. Effect of the grain protein content locus Gpc-B1 on bread and pasta quality. Journal of Cereal Science. 51:357-365.
Zhang, J., Martin, J.M., Beecher, B.S., Morris, C.F., Hannah, L.C., Giroux, M.J. 2009. Seed-specific expression of the wheat puroindoline genes improves maize wet milling yields. Plant Biotechnology Journal. 7: 733-743.
Chen, F., Beecher, B.S., Morris, C.F. 2010. Physical Mapping and a new puroindoline b-2 gene in wheat. Theor. Appl. Genet. 120:745-751.
Chen, F., Zhang, F., Morris, C.F., Xu, H., He, Z., Xia, X., Cui, D. 2010. Molecular characterization of the Puroindolin a-D1b allele and develpment of an STS marker in wheat (Triticum aestivum L.). Journal of Cereal Science. 52:80-82.
Finnie, S.M., Jeannotte, R., Morris, C.F., Giroux, M.J., Faubion, J.M. 2010. Variation in polar lipids located on the surface of wheat starch. Journal of Cereal Science. 51:73-80.
Finnie, S.M., Jeannotte, R., Morris, C.F., Giroux, M.J., Faubion, J.M. 2010. Variation in polar lipid composition within near-isogenic wheat lines containing different puroindoline haplotypes. Journal of Cereal Science. 51:66-72.