Disease stress-inducible genes of tobacco: expression profile of elicitor-responsive genes isolated by subtractive hybridization

In order to investigate the change in mRNA profile during tobacco disease response, a subtractive hybridization procedure was used to generate a cDNA library for genes induced in tobacco (Nicotiana tabacum cv. Samsun NN) treated with oomycete elicitor. Database searches with the randomly isolated genes revealed that this cDNA library was enriched for reported disease stress-responsive genes such as pathogenesisrelated proteins and cell wall protein genes. The expressions of eight newly isolated genes were induced by inoculation with the non-pathogenic bacteria, Pseudomonas syringae pv. glycinea. The NtEIGs (N. tabacum elicitor-inducible genes) showed similarity to genes for stellacyanin-like protein (NtEIG-A1), glutathione peroxidase (NtEIG-C08), extensinlike protein (NtEIG-C29), WRKY transcription factor (NtEIG-D48), glycine rich protein (NtEIG-E17), b-1, 3-glucanase-like protein (NtEIG-E76), photoassimilate-responsive protein-1 (NtEIG-E80) and wound-induced protein (NtEIGD10). The expression patterns of NtEIGs in tobacco leaf in response to P. syringae pv. glycinea, salicylic acid (SA), methyl jasmonate (MeJA) and wound stress were analysed. The individual expression patterns of NtEIGs indicate that the transcriptional activation of NtEIGs is regulated by various signals and the products of NtEIGs are involved in different processes at different stages of the plant defence responses.