Advances in somatic cell hybridization in higher plants

Abstract

Advances in tissue culture and protoplast technology make it possible to investigate genetic manipulation of somatic plant cells. The development of a new and efficient technique has resulted in fusion of protoplasts and the production of intergeneric hybrids between cells of various cultivated plants. The results indicate that the natural barriers which prevent sexual crosses between plant genera are circumvented in the fusion and growth of somatic hybrid cells. Appropriate selection systems which permit isolation of hybrids and elimination of all parental cells are being developed. It will then be possible to obtain clones and determine the stability of the karyotypes, which consist of a combination of the parental chromosomes, and utilize the materials for biochemical and genetic analyses. Present techniques also permit investigation of the uptake of nuclei, plastids and other organelles by protoplasts. Organelle transfer to protoplasts and subsequent reconstitution of the cells may provide an elegant approach for genetic analyses and for investigations on gene control of biochemical and developmental processes in higher plants. Genetic modification through DNA uptake may also be feasible. The practical value of the technique may be limited unless plant DNA can be used. Progress in the development of such genetic transformation procedures depends upon the choice of lines with an easily recognized phenotypic variation. Plant regeneration from the hybrids and genetically modified cells can be expected as methods are developed for inducing differentiation and plant regeneration. Present progress in tissue culture and genetic manipulation procedures makes it possible to direct their application to problems of practical importance. The somatic cell fusion method would make it possible to obtain a large variety of crosses. The products of these combinations may then be employed in conventional plant breeding systems. Somatic cell genetics, thus, provide the means to transfer desirable characteristics between plants of different families.