Characterization of a diffusible signal capable of inducing defense gene expression in tobacco

Joseph Chappell*, Alex Levine, Raimund Tenhaken, Marcos Lusso, Chris Lamb

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Treatment of tobacco (Nicotiana tabacum) cell-suspension cultures with cryptogein, an elicitin protein from Phytophthora cryptogea, resulted in the release of a factor(s) that diffused through a 1000-D cutoff dialysis membrane and was capable of inducing sesquiterpene cydase enzyme activity (a key phytoalexin biosynthetic enzyme in solanaceous plants) when added to fresh cell-suspension cultures. The diffusible factor(s) was released from cells over a 20-h period and induced a more rapid induction of cyclase enzyme activity than did direct treatment of the cultures with pure elicitin protein. The diffusible factor also induced a more rapid accumulation of transcripts encoding for sesquiterpene cyclase, acidic and basic chitinase, and hsr203 (a putative hypersensitive response gene) than did elicitin treatment. The diffusibie factor(s) was resistant to protease, pectinase, DNase, and RNase treatments, was not extractable into organic solvents, and was not immunoprecipitable when challenged with polyclonal antibodies prepared against elicitin protein. The diffusible factor(s) could not induce the release of more factor, suggesting that it was a terminal signal. These results are consistent with the notion that cells directly challenged or stimulated by pathogen-derived elicitors release diffusible secondary signal molecules that orcbestrate the induction of complementary defense responses in neighboring cells.

Original languageAmerican English
Pages (from-to)621-629
Number of pages9
JournalPlant Physiology
Issue number2
StatePublished - Feb 1997


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