ALCOHOL-DEHYDROGENASE IN ARABIDOPSIS - ANALYSIS OF THE INDUCTION PHENOMENON IN PLANTLETS AND TISSUE-CULTURES

Alcohol dehydrogenase (ADH) activity is expressed in Arabidopsis seeds and tissue cultures. During the germination process, ADH activity declines rapidly and is no longer detectable in 9- to 10-day-old seedlings. The synthesis of ADH could be demonstrated in seedlings submitted to anaerobiosis by 35S-methionine incorporation studies. Callus, induced from seeds or leaves on a (2,4-D)-containing medium, and cell suspension cultures are characterized by a high level of ADH activity. The incorporation of 35S-methionine and 2-dimensional electrophoresis indicated that ADH induction was due to de novo synthesis of the polypeptides. In vitro translation of total poly (A)+-RNA from seedlings and callus showed that only callus mRNA was able to direct the synthesis of ADH polypeptides. This demonstrates the de novo synthesis of ADH mRNA during callus induction. Northern blot hybridization, using in vitro labeled ADH1-F DNA from maize as a probe, revealed sequence homology at the mRNA level between Arabidopsis and maize.