煙草crown gall tumor의 形成과 脫分化

Formation and dedifferentiation of crowm gall tumor in nicotiana tabacum

This study was carried out to clarify the effects of phytohormone, carbon source, and temperature on the growth of calluses induced from the crown gall tumor of Nicotiana tabacum var. Bright Yellow 4. Crown gall tumors were induced from stem tissues of Nicotiana tabacum var. Bright Yellow 4 by Agrobacterium tumefaciens. Therefore, it was clarified that genes on a special area of Ti-plasmid, called T-DNA, became integrated and expressed in the nuclear DNA of Nicotiana tabacum var. Bright Yellow 4. The crown gall tumor tissues could be cultured on the media which did not contain any auxins or cytokinins, and white and compact calluses were observed. However, normal tissues did not grow in vitro in the absence of the phytohormones. The tumor calluses were formed profusely when cultured on the media supplemented with IAA. On the other hand, the tumor calluses tended to be formed more profusely on the medium supplemented with 5mg/ℓ IAA. The media with cytokinins, kinetin and BA, produced poor result. As for the effect of carbon sources on the growth of tumor calluses, the calluses were formed on the media with sucrose more profusely than on the media with glucose. The concentration of sucrose used for callus induction from tumor tended to be lower than that for callus formation from normal tissus and the most effective concentration of sucrose was 20 g/ℓ And the optimal temperature for the growth of tumor callus was 25℃.