The versatile role of homologous recombination in plant cell: Repair of DNA damage, stress-directed genome evolution and foreign DNA integration

Homologous recombination represents a DNA repair pathway. Its role in a plant cell is not limited to double strand break repair. It also extends to genome evolution via rearranging of DNA sequences, and has an important application in foreign DNA integration in the plant genome. Our study demonstrated that effects exerted by stress on homologous recombination and genome stability are not restricted to the exposed generation. The progeny of plants exposed to stress exhibited elevated spontaneous homologous recombination, changes in DNA methylation and higher tolerance to stress. These heritable changes are mediated by an unknown stress-inducible epigenetic signal. Furthermore, we demonstrated that using factors that enhance homologous recombination can improve the efficiency of genetic transformation by Agrobacterium . We have developed and patented a plant growth medium enhancing homologous recombination and significantly increasing the transformation frequency. The role of several other chemicals for the improvement of transformation was also evaluated.