Early Changes in Gene Expression in Tobacco Cells Elicited with Cryptogein. L. Suty. Unite associee 692 INRA/Universite de Bourgogne, Laboratoire de Phytopharmacie, INRA, BV 1540 21034 Dijon Cedex, France. J. P. Blein(1), P. Ricci(2), and A. Pugin(1). (1)Unite associee 692 INRA/Universite de Bourgogne, Laboratoire de Phytopharmacie, INRA, BV 1540 21034 Dijon Cedex, France; (2) Station de Botanique et Pathologie Vegetale, INRA, BP 2078 Antibes Cedex 06606, France. MPMI 8:644-651. Accepted 19 June 1995. Copyright 1995 The American Phytopathological Society.

Isolated tobacco cells were used to examine early changes in gene expression induced by elicitation with the prolein-aceous elicitor cryptogein. A two-dimensional electro-phoresis strategy was carried out Tor the identification of marker polypeptides of elicitalion. After 30 min of elicitation, 20 polypeptides appeared or increased in intensity, whereas the amounts of three other polypeptides decreased. Two-dimensional electrophoresis patterns obtained after mRNA translation in vitro revealed that the synthesis of about eight polypeptides could be regulated by the level of mRNAs. The accumulation of mRNAs encoding several known plant proteins was further examined by Northern and slot blot hybridizations. The results indicate (i) a significant transitory accumulation 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 strong accumulation of mRNA encoding 3-hydroxy-3-methyIglutaryl coenzyme A reductase (EC 1.1.1.34), and (iii) a slow accumulation of mRNA encoding phenylalanine ammonia lyase (EC 4.3.1.5) and the patho-genesis-related protein PR-bl. These results indicate that early changes in gene expression occur in the elicitation process and concern key plant enzymes.