VIRUS-INDUCED GENE-EXPRESSION FOR ENZYMES OF ETHYLENE BIOSYNTHESIS INHYPERSENSITIVELY REACTING TOBACCO

A full-length cDNA clone (cEFE-26) encoding ethylene-forming enzyme (E FE) was isolated from a cDNA library prepared from leaves of tobacco m osaic virus (TMV)-infected tobacco cultivar Samsun NN. The cDNA clone encodes a protein with 90% amino acid sequence similarity to establish ed EFEs of tomato and other plants, By using cEFE-26 cDNA and the inse rt from cDNA clone pACC13 (B. A, Bailey, A, Avni, N, Li, A, K, Mattoo, and J. D, Anderson, Plant Physiol, 100:1615-1616, 1992) encoding toba cco 1-aminocyclopropane-1-carboxylic acid synthase as probes, it was e stablished that tobacco contains small gene families for these protein s, Furthermore, RNA blot analyses indicated that transcript levels in leaves for the two ethylene pathway genes were elevated after infectio n with TMV, The results are discussed in relation to a possible signal ling role of ethylene in induced resistance and gene expression for pa thogenesis-related proteins.