|Fernandez DE Soto, Jose - UNIV OF CALIF, DAVIS|
|Chicaiza, Oswaldo - UNIV OF CALIF, DAVIS|
|Dubcovsky, Jorge - UNIV OF CALIF, DAVIS|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2006
Publication Date: May 18, 2006
Citation: Bregitzer, P.P., Fiedler, D.J., Blechl, A.E., Lin, J.W., Sebesta, P.G., Fernandez De Soto, J., Chicaiza, O., Dubcovsky, J. 2006. Changes in high molecular weight glutenin subunit composition can be genetically engineered without impacting wheat agronomic performance. Crop Science. 46:1553-1563 (2006) Interpretive Summary: Bread wheat flour owes its unique ability to produce high quality breads to specialized proteins deposited in the wheat kernel. The proteins, called high molecular weight glutenins (HMWGs), make doughs elastic and allows them to trap the gas bubbles produced by yeast and to rise. As a means of improving the breadmaking qualities of wheat, genetic engineering has been used to change the levels of these proteins. To be useful for the production of new, improved wheat varieties, these changes must be good for bread quality without affecting the productivity of the wheat plant. To discover whether wheat lines altered for the HMWGs had good performance for various growth characteristics including grain yield, field trials were conducted in Idaho and California. The results showed that, although some of the lines did not perform as well as unaltered wheat, many had very good characteristics that would be acceptable for commercial production. Therefore, genetic engineering can be used to produce wheat that has desirable end-use quality changes and is healthy and productive.
Technical Abstract: The genomes of modern cultivars have been painstakingly selected for the presence of favorable alleles at multiple loci, which interact to produce superior phenotypes. Genetic transformation provides a tool to introduce new genes without altering the original gene combinations. However, the random genetic and epigenetic changes sometimes generated by the transformation process has been associated with losses in agronomic performance. The agronomic performance of 54 transgenic wheat (Triticum aestivum L.) lines containing additional copies of native or modified high-molecular weight glutenin subunit (HMW-GS) genes and/or the selectable marker bar, their untransformed parent 'Bobwhite', and 10 null segregant (non-transgenic) lines were assessed in small plot trials over two years and three locations. Most of the transgenic lines did not show significant changes in performance relative to Bobwhite, although the transgenic lines as a group tended towards lower performance. Null-segregant and bar-only lines performed similarly to Bobwhite and no relationship could be established between performance and particular transgenes or their expression levels. Despite the overall lower performance of the transgenic lines, many with agronomic performance equivalent to Bobwhite were identified. These findings suggest that extant techniques for genetic engineering of wheat are capable of producing agronomically competitive lines for use as cultivars or parents in breeding programs.