Open AccessSpatial and Temporal Induction of Cell Death, Defense Genes, and Accumulation of Salicylic Acid in Tobacco Leaves Reacting Hypersensitively to a Fungal Glycoprotein Elicitor
Author(s) -
Stéphan Dorey,
Fabienne Baillieul,
Marie-Agnès Pierrel,
Patrick Saindrenan,
Bernard Fritig,
Serge Kauffmann
Publication year - 1997
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.1997.10.5.646
Subject(s) - elicitor , salicylic acid , phenylpropanoid , scopoletin , biology , metabolite , programmed cell death , cell wall , biochemistry , gene , biosynthesis , apoptosis , medicine , alternative medicine , pathology
We have analyzed the spatial and temporal expression of defense responses induced in attached tobacco leaves treated with a Phytophthora megasperma glycoprotein that was previously shown to be an efficient elicitor of the hypersensitive reaction. The infiltrated tissue (zone 1), the surrounding tissue (zone 2), which is 5 mm in width, and tissue at a distance >2 cm from zone 2 (zone 3) were analyzed separately. Cell death occurred only in zone 1 and was completed by 14 h. Defense gene expression was induced in zones 1 and 2 with striking differential patterns, but not in zone 3. There was a rapid (1 to 4 h) induction of genes of the phenylpropanoid, salicylic acid, and ses-quiterpenoid pathways in zones 1 and 2. However, it was strong and transient in the former and of lesser extent but sustained in the latter. High amounts of scopoletin, a phenylpropanoid metabolite, were found synthesized in zone 2. Pathogenesis-related (PR) transcripts and the corresponding PR proteins accumulated in high amounts in zone 2 rather late after the treatment (24 h). Salicylic acid was synthesized in both zone 1 and zone 2. Using a radioactively labeled elicitor, we demonstrated that the elicitor remained strictly localized to zone 1. The results provide strong evidence that an endogenous cell-to-cell signaling mechanism was triggered and occurred between the elici-tor-treated cells (zone 1) and the surrounding cells (zone 2), where it induces strong defense responses without cell death.