EARLY CHANGES IN GENE-EXPRESSION IN TOBACCO CELLS ELICITED WITH CRYPTOGEIN

Isolated tobacco cells were used to examine early changes in gene expr ession induced by elicitation with the proteinaceous elicitor cryptoge in. A two-dimensional electrophoresis strategy was carried out for the identification of marker polypeptides of elicitation. After 30 min of elicitation, 20 polypeptides appeared or increased in intensity, wher eas the amounts of three other polypeptides decreased. Two-dimensional electrophoresis patterns obtained after mRNA translation in vitro rev ealed that the synthesis of about eight polypeptides could be regulate d by the level of mRNAs. The accumulation of mRNAs encoding several kn own plant proteins was further examined by Northern and slot blot hybr idizations. The results indicate (i) a significant transitory accumula tion of mRNA encoding plasma membrane H+-ATPase (EC 3.6.1.35), between 5 and 30 min after the addition of the elicitor, (ii) a fast and stro ng accumulation of mRNA encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34), and (iii) a slow accumulation of mRNA encodi ng phenylalanine ammonia lyase (EC 4.3.1.5) and the pathogenesis-relat ed protein PR-b1. These results indicate that early changes in gene ex pression occur in the elicitation process and concern key plant enzyme s.