CISGENESIS IS A PROMISING APPROACH FOR FAST, ACCEPTABLE AND SAFE BREEDING OF PIP FRUIT

Abstract

Introgression of traits from wild germplasm into pip fruit cultivars by means of classical breeding is painstakingly slow. Introgression of e.g., the apple scab resistance gene Vf from Malus floribunda 821 into marketable high quality apple cultivars took approximately 50 years. In the mean time the Vf resistance is being broken down in Europe. For durable resistance, different resistance genes should be accumulated. However, this may take another series of decades. This slow tempo is caused mainly by the long juvenile period of apple and the phenomenon that not only the allele of interest is inherited by the progeny, but also hundreds of unwanted alleles. The process would be much faster if only the allele of interest was inserted, without unwanted alleles. This can be achieved by cisgenesis. We defined cisgenesis as genetic modification of plants, inserting alleles of the plant itself or from crossable relatives. The allele should contain its native introns and should be flanked by its native promoter and terminator in sense-orientation. If the plant is equipped with foreign genes from outside the gene pool of the conventional breeder, the plant is named transgenic. Inquiries indicate that cisgenic plants are more acceptable to consumers than transgenic plants. As the phenotypic result of cisgenesis can, in principle, also be obtained by means of conventional breeding or translocation breeding, cisgenic plants are as safe as plants from conventional breeding or mutation breeding. Therefore we have proposed to treat cisgenic plants like conventionally bred plants, by exempting cisgenic plants from the GMO regulation. The number of isolated, functionally analysed genes and their alleles from fruit tree crops is increasing. Also technologies are available for introduction of these alleles without leaving selection genes behind. Cisgenesis is combining the knowledge of native alleles with marker free technologies. Cisgenesis is a promising path for utilizing the wealth of knowledge on plant genes to the benefit of the society in a fast, safe, and acceptable way.