Genetic Transformation and Regeneration of Legumes

Abstract

A wide range of legume species have been genetically transformed and the transformants regenerated to provide novel genotypes. Methods used for transformation include the use of Agrobacterium tumefaciens, A. rhizogenes, particle bombardment and electroporation. Although Agrobacterium-based methods using a wide variety of tissue explants have been the most widely used, they generally yield low rates of transformation (0.1-5%). In planta techniques, either with Agrobacterium or electroporation of intact meristems, hold the promise of much higher frequencies and more simple means of regeneration of transformants. Most commonly the GUS reporter gene [uidA] or genes for antibiotic resistance (npt and hpt) have been used as selectable markers. More recently, genes conferring tolerance to herbicides (bar/pat for glufosinate, or aroA and cp4/gox for glyphosate resistance) have been more effective. These genes have also provided the basis for engineering novel herbicide-tolerant cultivars of a number of crop species. Genetic engineering to enhance the nutritional quality of grain or herbage, or to insert genes associated with symbiotic root nodule formation have also been produced. A detailed summary of procedures developed for the A.tumefaciens-mediated transformation of narrow-leafed lupin (Lupinus angustifolius) to create stable glufosinate-resistant cultivars is presented.