Submitted to: International Wheat Scab Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 25, 2004
Publication Date: December 10, 2004
Citation: Satyavathi, V.V., Jauhar, P.P., Dahleen, L.S. 2004. Optimization of an agrobacterium-mediatiated transformation system for durum wheat. Proceedings of the 2nd International Symposium on Fusarium Head Blight; incorporating the 8th European Fusarium Seminar; Dec. 11-15, 2004, Orlando, Fl. Vol.1, pp. 254. Interpretive Summary: Durum wheat, also called macaroni wheat, is an important cereal crop grown in the United States, Canada, and several European countries. Conventional breeding, and tools of cytogenetics and biotechnology have been used for durum improvement. More recently, genetic engineering has been used for improvement of several crops including wheat. Direct gene transfers into plants have been achieved by shooting genes into their cells using a gene gun and then regenerating full plants, which then have the desired gene. Earlier, we standardized an efficient method for genetic engineering and produced the first transgenic durum wheat with marker genes. Using the same transgenic technology, we are inserting several disease resistance genes into durum cultivars. Compared to the direct gene transfer method using a gene gun, desirable genes can be inserted into plant cells more effectively by infecting them with certain bacteria. In this report, we describe our efforts in standardizing such a technique using a bacterial strain to transfer genes into durum cultivars.
Technical Abstract: Genetic manipulation by transformation via direct gene transfer can be a valuable adjunct to traditional plant breeding. The tools of direct gene transfer help engineer into plants new traits that are otherwise very difficult to introduce by conventional breeding. Methods of inserting genes into plant cells include biolistics particle bombardment or microprojection, electroporation, vacuum infiltration, and Agrobacterium-mediated systems. Of these, microprojection has been the most widely used and we standardized this technique for durum wheat (Triticum turgidum L.). However, this technique is hampered by the occurrence of multiple gene insertions and gene silencing. Agrobacterium-mediated transformation suffers less from these drawbacks but has been limited mostly to dicotyledonous plants. Although Agrobacterium is currently employed for transformation of some monocots including bread wheat, it has not been used for durum wheat transformation so far. Having standardized an efficient in vitro regeneration system for a current commercial durum cultivar Maier, we are using isolated scutella and one week-old-calli from this cultivar for transformation with a disarmed Agrobacterium tumefaciens strain AGL1 harboring the binary vector containing the reporter gene, b-glucuronidase (GUS), and the bar gene as a selectable marker. Various factors influencing transformation efficiency, such as explant tissue, particle bombardment before infection, and duration of co-cultivation are being considered for optimization of Agrobacterium-mediated transformation protocol for durum wheat to insert anti-fungal genes.