COMPARATIVE-STUDIES ON POTATO-TUBER DEVELOPMENT USING AN IN-VITRO TUBER INDUCTION SYSTEM

A method for synchronized in vitro tuber induction in a Hungarian cult ivar of Solanum tuberosum designated ''Keszthelyi 855'' has been devel oped. It was shown that in this system tuberization and stolen elongat ion primarily depend an the level of sucrose in the medium. The cytoki nin, 6-bensylaminopurine (BAP), also enhances the efficiency of tuber formation, however, only at sucrose concentration above 4% (w/v). The synchronized plant culture provided starting material for isolation of genes specifically expressed in tuberizing Solarum species during the early stage of tuber development. In comparison with the non-tuberizi ng Solanum brevidens, three types of specific transcripts have been ob tained by differential screening. Based on DNA sequence analysis the g enes isolated code for the major tuber proteins, patatin and proteinas e inhibitors.