A Potato Gene Encoding a WRKY-like Transcription Factor Is Induced in Interactions with Erwinia carotovora subsp. atroseptica and Phytophthora infestans and Is Coregulated with Class I Endochitinase Expression

摘要

A potato gene encoding a putative WRKY protein was isolated from a cDNA library enriched by suppression subtractive hybridization for sequences upregulated 1 h post-inoculation with Erwinia carotovora subsp. atroseptica . The cDNA encodes a putative polypeptide of 172 amino acids, containing a single WRKY domain with a zinc finger motif and preceded by a potential nuclear localization site. St-WRKY1 was strongly upregulated in compatible, but only weakly in incompatible, interactions with Phytophthora infestans where, in all cases, it was coregulated with class I endochitinase, associating its expression with a known defense response. Whereas St-WRKY1 was strongly induced by E. carotovora culture filtrate (CF), confirming it to be an elicitor-induced gene, no such induction was detected after treatment with salicylic acid, methyl jasmonate, ethylene, or wounding. St-WRKY1 was upregulated by treatment of potato leaves with CFs from recombinant Escherichia coli containing plasmids expressing E. carotovora pectate lyase genes pelB and pelD , suggesting that either proteins encoded by these genes, or oligogalacturonides generated by their activity, elicit a potato defense pathway associated with St-WRKY1 .