• Journal of Yeungnam Medical Science
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• v.1 no.1
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• pp.41-48
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• 1984

The soil bacterium Agrobacterium tumefaciens is a plant pathogen that cause3 crown gall tumors by infecting the wounded dicotyledonous plants and subsequent integration of bacterial DNA into plant nuclear DNA. Virulent A. tumefaciens strains harbor a large Ti (tumor-inducing) plasmid that carries genes essential for tumorigenesis. In the present study, 13 strains (Malus pumila Mill; $A_{1-3}$, Populus monilifera; $W_{1-6}$, Populus tomentiglandlosa; $P_{1-3}$ and Rosa species; $R_1$) of Agrobacterium isolated in korean crown gall tumors and plasmids were observed in 6 strains ($W_2$, $W_3$, $W_6$, $P_1$, $P_3$ and $A_2$). The test for crown gall tumor formation was resulted only in ATCC15955 and $KW_2$ strains inoculated into the stem of sun flower and the development was observed for 4 and 6 weeks after inoculation. Above two Ti plasmids (pTi) were purified by cesium chloride-ethidium bromide density gradient centrifugation and digested with restriction enzyme and fragments of pTiATCC 15955 and $pTiKW_2$ observed by EcoR I ; 25&27, Hind III; 23&21, BamH I ; each 20 and Hpa I ; 12&27, and sizes of pTiATCC15955 and and $pTiKW_2$ calculated as 200 and 87 kbases. Octopine was isolated from tumor tissue ($W_{1-6}$ and $P_{1-3}$) and these strains confirmed as octopine type.