POTATO TRANSGENOSIS BY T-DNA MORPHOREGULATORY GENES

Potato cultivars were transformed by Agrobacterium tumefaciens system carrying the helper plasmid pAL4404 and a series of vector plasmids wh ich bring into the plant genome the selectable kanamycin resistance ge ne together with individual A. tumefaciens indvidual T-DNA morphoregul atory genes and their combinations. Introduction of genes 1 and 2 into the potato genome leads to the formation of undifferentiated, phytoho rmone independent rapidly growing white tumors tissues which never reg enerated plants or organs in the in vitro cultures. Gene 5 added to T- DNA construction did not change the plant tissue response picture. Tra nsgenosis by vectors carrying T-DNA gene 4 led to the formation of ter atoma tissues which in later generations sometimes showed normalizatio n. Transgenic plants were often characterized by intense branching of shoots, delayed development and sometimes also aberrant inflorescence formation They showed increase of the number of tubers, but decrease o f the overall mass and decrease of the yield. Gene 5 introduced into t he plant genome to frequent branching of higher parts of shoots, decre ase of the number and size of leaves and decrease of rooting ability i n agar cultures, but roots appeared in lower, aerial parts of shoots o f in vitro cultures. After transfer to the soil, transgenic plants sho wed standard phenotype. An introduction of gene 6b led to the formatio n of plants which were characterized by intense in vitro growth but in soil they showed standard phenotype.