Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2002
Publication Date: 7/30/2002
Citation: MANOHARAN, M., DAHLEEN, L.S. GENETIC TRANSFORMATION OF THE COMMERCIAL BARLEY (HORDEUM VULGARE L.) CULTIVAR CONLON BY PARTICLE BOMBARDMENT OF CALLUS. PLANT CELL REPORTS. 2002. VOL. 21:76-80. Interpretive Summary: The insertion of single genes into barley has the potential to increase disease resistance, reduce toxin levels, and improve quality and nutrition of the grain. One limit to the use of the technology has been failure in transforming adapted types of barley. The varieties that have been transformed do not grow well in the major barley growing areas of the United States, making them hard to use for developing improved varieties. We have successfully inserted a selectable marker gene into the two-rowed malting barley Conlon using techniques recently developed for adapted varieties. The inserted gene was transmitted to progeny plants as expected for a single gene. These results show that inserting useful genes directly into adapted, high quality barley is now possible.
Technical Abstract: Attempts to transform the commercial barley cultivars with agronomically important genes have not been successful because of the lack of an efficient regeneration system. By modifying certain components in the standard culture medium, a reproducible and efficient regeneration system have been developed. We obtained herbicide-resistant transgenic plants from barley (Hordeum vulgare L. cv. Conlon), using this medium. Embryo-derived callus was bombarded with pAHC25, containing the screenable marker gus and the selectable marker bar, both driven by the maize ubiquitin promoter (Ubi1) and followed by the nos terminator. After bombardment, callus was transferred to callus-induction medium with 5 mg/L bialaphos for selection. Resistant calli were transferred to maintenance medium with 5 mg/L bialaphos for further selection, and finally transferred to regeneration medium with 5 mg/L bialaphos. Green shoots that developed on regeneration medium were transferred to rooting medium with 3 mg/L bialaphos. Eighty five transgenic plants were obtained from 13 independent transformation events. Progeny tests showed Mendelian inheritance for the transgenes. This is the first report of the production of large numbers of transgenic plants from a commercial cultivar adapted to midwestern US barley production.