In planta strategy for gene transfer into plants: embryo transformation

Abstract

Tissue culture-plant regeneration has been an indispensable and integral part of transgenic technology. Nevertheless, realization of whole plant transformants has been a problem in a large number of crop species as these plants have proven to be highly recalcitrant in vitro. Consequently, strategies are being evolved wherein the tissue culture component is eliminated in the procedure. These are mostly in planta methods. This review presents one such in planta method demonstrated to transform three important recalcitrant crops viz., sunflower, safflower and peanut. The method essentially involves infection of embryos (young seedlings) with Agrobacterium and allowing the seedling to grow into a mature plant. The T sub(0) and T sub(1) generation plants are later subjected to analysis for the presence of transgenes. This method is not only tissue culture-independent but also is genotype-independent and permits screening of a large number of transformants in a short span of time. Tissue culture-induced variations are also avoided. The utilization of the strategy reported may help future efforts in designing transformation procedures for other difficult-to-regenerate plant species.