Novel Gene Transfer Technologies

Gene transfer is the process by which a gene from any source can be introduced into plant cells or tissues. Gene transfer technologies are used to manipulate plant cells for scientific research as well as for commercial purposes like production of transgenics. Transgenic plants generated using these technologies are used either for field deployment or for identifying and evaluating gene and promoter function. In the last few decades, significant developments have been made in gene transfer technology since the discovery of Agrobacterium tumefaciens as a natural tool for plant transformation, and there is a long list of transgenic crop varieties that have now been released for commercial production. These advances are related to major improvements in Agrobacterium-mediated and direct DNA delivery techniques, along with modifications in tissue culture techniques for regenerating transgenic plants from transformed cells or tissues. Bananas are not lagging too far behind in this race, with many laboratories engaged in field trials of transgenic bananas carrying genes of interest. With efficient gene transfer technologies available for banana, banana transformation research is now more focussed on the problems associated with generating cell suspensions of recalcitrant cultivars, identifying useful gene/trait associations, promoters and problems associated with stable integration and reliable expression of the DNA once it has been integrated. This chapter focuses on the gene transfer technologies currently available for generating transgenic banana cultivars and summarises the various traits of interest for which genes have been transformed into bananas.