Gene transfer in legumes (2013)

Plant transformation may be defined as the sequence of delivery, integration and expression of foreign genes into the plant cells which will ultimately regenerate into a whole plant. This ability to introduce and express or inactivate specific genes in the plant genomes provides a new and powerful experimental tool for validating gene function, particularly in relation with various plant physiology mechanisms and processes that have not been resolved so far using other biochemical approaches. Another non-negligible application of this approach is that of obtaining and transferring genes that are not available to a given species due to sexual incompatibility from other plants, from microorganisms or even animals. The process involves choosing a trait, identifying and isolating the gene(s) encoding it. To be functional, such gene(s) must include the regulatory regions ensuring their correct expression in the plant. Then, a reliable protocol must be devised and followed for the transformation of genes into plants, and the DNA sequences introduced must subsequently be integrated, expressed and maintained in the genome throughout subsequent cell divisions and progenies. Finally, transformed cells must be competent for regeneration into whole plants. Gene delivery systems used to date can be divided into direct gene transfer (mediated by physical or chemical forces for delivery of the gene into plant protoplasts, cells and even tissues) and Agrobacterium-mediated gene transfer, where either A. tumefaciens or A. rhizogenes is used as vectors for introducing the foreign gene into the plant genome. In this context, recombinant DNA technology has revolutionised biotechnology in such a way that plant transgenesis is now a relatively mature approach, and plant biotechnology provides today not only novel genotypes which carry agronomically useful genes for biotic and abiotic stresses, but also others that improve plant nutrition or increase yield components.

Progress in Botany. Volume 74 of the series Progress in Botany pp 37-100. DOI 10.1007/978-3-642-30967-0_2 Print ISBN 978-3-642-30966-3 Online ISBN 978-3-642-30967-0