The biotechnology of crop legumes

Abstract

The absence of variety-independent gene transfer methods for major agronomic species has, until now, limited the usefulness of recombinant DNA techniques to crop improvement programs. Until recently, only Solanaceous crops could be used to study fundamental and applied problems in plant sciences. During the past five years rapid advances in cell biology, in combination with the development of novel gene transfer methodology allowed utilization of the tools of plant molecular biology in conventional breeding programs. Cereal and leguminous species were considered to be recalcitrant to genetic manipulation. As a result of the development of direct DNA transfer methodology into organized tissue, we are now in a position to introduce any foreign gene into almost all of the major cereals and legumes. This can be achieved efficiently, often in a variety-independent fashion. The object of this review is to provide a comprehensive account of the state of the art in gene transfer for the cultivated leguminous crops. Important oilseed and feed species primarily in industrialized countries, as well as minor but equally important species for sustaining growth populations in developing countries will be examined. Advantages of the various gene transfer methods that were shown to be useful for specific crops, as well as limitations and problems associated with each crop and gene transfer method will be discussed. Data from field trials of transgenic legumes, where available, will be presented.

Grain protein estimation and SDS-PAGE profilingof six important arid legumes

“…Their ability to succeed in the arid or semi-arid habitats is related to nitrogen-demanding metabolism (Sprent and McKey, 1994;Sprent, 2001). Leguminosae family contains some 670 genera (Polhill and Raven, 1981;Polhill 1994), more than 21,000 species (Christou, 1994) and 39 tribes. But, a recent phylogenetic analysis based on intensive molecular studies identified 727 genera, 19,327 species and 36 tribes (Lewis et al, 2005).…”

Expression Studies of Superoxide Dismutases in Nodules and Leaves of Transgenic Alfalfa Reveal Abundance of Iron-Containing Isozymes, Posttranslational Regulation, and Compensation of Isozyme Activities

“…Complete cDNA clones encoding some enzymes of each type have been isolated and used to construct transgenic plants overexpressing SODs in the chloroplasts, mitochondria, and cytosol (Bowler et al 1991;Scandalios 1993;Van Camp et al 1996). These studies were performed using model plants for transformation, such as tobacco, but important crop legumes can now be transformed and regenerated with relative ease (Christou 1994). Because legumes are unique amongst crop plants in their ability to fix atmospheric N 2 in symbiosis with rhizobia, transformation of these plants with antioxidant genes could provide additional advantages related to its protective role in nodule activity (Puppo et al 1982;Dalton et al 1998;Matamoros et al 1999).…”

Physiological Responses of Grain Legumes to Stress Environments

“…Grain legumes were originally considered to be recalcitrant to genetic manipulation. However, as a result of the recent development of direct DNA transfer technology into organized tissue, it is possible to introduce any foreign gene into most of the grain legumes (Christou, 1994).…”