Submitted to: Plant Cell Reports
Publication Type: Abstract only
Publication Acceptance Date: 1/14/1999
Publication Date: N/A
Citation: Interpretive Summary: Genetically engineering cereal grain crops, such as oat and barley, is a promising process that will enable more efficient development of improved crop characteristics. Many problems remain to be solved before this technique becomes routine and cheap. The research reported here addresses one of the major problems, that the cultured cells (called callus) used for most barley and oat engineering work impose major limitations on the success of the genetic engineering project. Part of the problem with using cultured callus cells is that their growth in the laboratory is very different from their normal developmental fate; that is, callus cells are very amorphous and do not develop green color or the organs most people would associate with a plant--such as shoots and leaves. We have developed a tissue culture system that is based on the growth of meristematic cells. Meristems are the normal plant organs that develop into recognizable plant parts such as shoots and leaves. These meristematic cell cultures are more similar to the cells that would be found in a normal plant; for instance, meristematic cultures are green, and frequently have recognizable leaves and shoots. In this report, we demonstrate that methods developed for genetically engineering callus cells can also be used to genetically engineer meristematic cells, and that the more- normal nature of the meristematic cells may impart some positive benefits to the genetically engineered plants that are developed using them.
Technical Abstract: Genetic transformation using shoot meristematic cultures (SMCs) derived from germinated seedlings is established in commercial varieties of oat cv. Garry and barley cv. Harrington. Six-month-old SMCs of oat were induced as described (Zhang et al. 1996b) and bombarded with bar and uidA; nine-month-old SMCs of barley were induced on an improved medium (MPM-MC) containing maltose and high-levels of copper and bombarded with bar/nptII and uidA. After 3 - 4 months on selection, seven independent transgenic lines of oat were obtained, two lines of barley. All transgenic lines produced T0 plants; five lines of oat and one line of barley were self-fertile, and the other barley line produced T1 seed when out-crossed. Both Mendelian and non-Mendelian segregation ratios of transgene expression were observed in T1 and T2 progeny of transgenic oat. Normal as well as low physical transmission of the transgenes was also seen in T1 and T2 progeny of oat. The bar- containing line of barley showed stable transgene expression in all T1 and T2 progeny tested.