Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 8, 2000
Publication Date: N/A
Interpretive Summary: Genetic engineering is a term that is used to describe a number of newly-developed and related technologies, one of which is the addition of genes to plants without sexual hybridization. This technology represents an important development which may be used to rapidly develop improved crops that are more productive, better quality, and less environmentally damaging to grow. Genetic engineering of barley has been hard, because genes can be delivered only to cells grown in the lab, not to whole plants. These lab-grown cells must be induced to recreate, or regenerate, an entire plant before any newly-added genes can be put into practical use. This regeneration process has been very difficult for barley, and ways to improve this process have been searched for. One way is to identify existing genes that are in barley which influence the regeneration process, and develop molecular "tags", or markers, for these genes. By examining the genetic material of particular plants for the presence of certain favorable forms, or alleles, at each of these genes for regenerability, researchers can select particular plants that should be the "best" regenerators, rehybridize them, and continue the selection process for better regeneration. Once such markers are developed, these examinations can be done in a matter of days, as compared to a matter of months for making actual measurements of regenerability. This study reports experiments that were done to identify markers for plant regenerability in barley, and demonstrates that the ability to regenerate plants from cultured cells of particular plants can be predicted based on their markers. These results can now be used to speed the development of more efficient systems for genetically engineering barley.
Technical Abstract: Genetic control of plant regeneration from cultured plant tissues has been documented for a number of species. The characterization and manipulation of loci that influence morphogenic responses may be useful for the development of highly regenerable germplasm or for physiological investigations. Quantitative trait loci (QTLs) for morphogenesis from barley cell cultures were identified based on associations of mapped markers with the regeneration responses of 77 doubled haploid (DH) lines derived from the cross Steptoe/Morex. Two models were developed, one describing green plant regeneration, and one describing albino plant regeneration, measured as the numbers of green and albino plants regenerated per g fresh weight of embryogenic callus. Approximately 62% and 12% of the observed variability for green and albino plant regeneration, respectively, was explained by the models. An independent data set was developed that consisted of the regeneration responses of additional DH lines which were chosen randomly from the same segregating population. The models were tested for their ability to predict the responses of these independent DH lines. This study identified new QTLs for plant regeneration (one for green plants and at least one for albino plants), and confirmed previously reported associations of three QTLs with green plant regeneration.