Genetic Transformation of Allocasuarina verticillata

Allocasuarina verticillata (Lam.) L. Johnson is a small tree of the Casuarinaceae family and is found on the coastal plains and ranges of New South Wales, Victoria, South Australia, and Tasmania (National Research Council 1984). This tree is usually 6 to 10 m high and has a beautiful spreading form which makes this species useful for shade and as an ornamental. Like other members of the Casuarinaceae family, A verticillata has the ability to fix nitrogen through a symbiotic association with a soil actinomycete, Frankia. Field studies have estimated fixation rates of 40–60 kg N/ha/year (Diem and Dommergues 1990). A. verticillata roots are also infected either by ectomycorrhizal fungi or by arbuscular endomycorrhizal fungi (National Research Council 1984). These symbiotic associations contribute to improved growth of Casuarinaceae tress on adverse sites and disturbed soils. A. verticillata has a rapid growth rate (up to 2m/year) and is planted for rehabilitation of eroded soils; it also tolerates wind, frost, drought, water-logging, and moderate salinity. In southern Australia, it has been used as a wind break; the highly branched twigs adsorb wind energy, thus contributing to stopping wind erosion, protecting crops, and increasing yields. This tress has been successfully introduced in Egypt, India, Israel, Cyprus, and South Africa (National Research Council 1984).