Genetic Transformation in Avena sativa L. (Oat)
Genetic transformation of cultivated hexaploid oat (Avena sativa L.) was first reported in 1992 (Somers et al. 1992). Since that time, the oat transformation system has been significantly improved. Current applications of transformation to oat improvement
- PDF / 1,550,414 Bytes
- 13 Pages / 439.37 x 666.142 pts Page_size
- 16 Downloads / 218 Views
1 Introduction Genetic transformation of cultivated hexaploid oat (Avena sativa L.) was first reported in 1992 (Somers et al. 1992). Since that time, the oat transformation system has been significantly improved. Current applications of transformation to oat improvement are focused on investigating mechanisms of resistance to barley yellow dwarf virus and fungal pathogens. This chapter reviews the key factors leading to the development of a routine transformation system for oat. The current status of oat transformation will be presented with consideration of selection systems and transgene inheritance in regard to eventual practical applications of transformation to oat improvement.
2 Development of the Transformation System 2.1 Totipotent Target Cells - Friable, Embryogenic Callus
Regeneration of fertile oat plants from tissue culture was first reported in 1976 (Cummings et al. 1976; Lorz et al. 1976). Immature embryos were used as the tissue culture explant and organogenic callus was thought to arise from the embryonic axis, most likely the mesocotyl (Cummings et al. 1976; Bregitzer et al. 1989). Progress in development of regenerable oat tissue culture systems was substantial during the 1980s (Heyser and Nabors 1982; Rines et al. 1992). However, protoplast culture systems, which were pursued by a number of researchers (Galston 1983; Tiburcio et al. 1986; Hahne et al. 1989), were not developed to the point where fertile plants could be routinely regenerated. Therefore, regenerable oat callus or suspension culture cells were clearly the most appropriate source of totipotent target cells for transformation. Ac[Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108, USA
2Plant Science Research Unit, US Department of Agriculture, Agricultural Research Service, St. Paul, Minnesota 55108, USA 3Departmento Plantas de Lavoura, Universidade Federal do Rio Grande do SuI, Puerto Alegro-RS 90012-970, Brasil
Biotechnology in Agriculture and Forestry, Vol. 38 Plant Protoplasts and Genetic Engineering VII (ed. by Y.P.S. Bajaj) © Springer-Verlag Berlin Heidelberg !996
Genetic Transformation in Avena sativa L. (Oat)
179
cordingly, further extensive improvements of the oat callus culture system from its original state were essential for the development of oat transformation technology. A specific genotype, termed GAF, that routinely produces highly regenerable callus, was selected from the progeny of a cross of the cultivar Garland by an accession of the wild oat A.fatua (Rines and Luke 1985). GAF and a daughter line derivative, GAF /Park, continue to be the genotypes most amenable to culture initiation and thus the transformation system (Bregitzer et al. 1989; Torbert et al. 1995). The observation and characterization of somatic embryogenesis in oat callus initiated from these genotypes and development of methods to routinely establish friable, embryogenic callus were key steps in the development of this culture system for oat transformation (Bregitzer et al. 1989,1995; Rines et al.
Data Loading...
