Poster: Plant Pathogen/Symbiont Interactions
Abs #
734: Evidence for the Non-correlation of AOS to Death Induction Initiated by a Proteinaceous Elicitor of Cryptogein on Tobacco Cells
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Presenter: |
Hirasawa, Ken-ichi , r5244001@ipc.shizuoka.ac.jp |
Authors | Hirasawa, Ken-ichi (A) Amano, Toyoki (A) Shioi, Yuzo (A) | | Affiliations: |
(A): Department of Biology and Geosciences, Faculty of Science, Shizuoka University
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Hypersensitive reaction is a programmed cell death in plant cell. Cryptogein is a proteinaceous elicitor secreted by Phythophthora cryptogea. This elicitor induces a remarkable and reproducible cell death on tobacco cells. Rapid and important calcium influx, alkalizations of extracellular medium, and transient production of active oxygen species (AOS) have been observed by cryptogein treatment. AOS is known as a key molecule involved in the execution of hypersensitive cell death. In the current model for death reaction, AOS is produced outside of the cells, and returns into the inside of the cells to initiate the death program.
In this study, we examine the effect of AOS scavengers during the death reaction of tobacco BY-2 cells. AOS is composed of several kinds of species, such as superoxide radical, hydrogen peroxide, hydroxyl radical, and singlet oxygen. We employed various scavengers for AOS, which are specific for each of those species. It is known that tiron is scavenger of superoxide radical, and catalase for hydrogen peroxide. Hydroquinone, sodium ascorbate and propyl gallate are effective for free radicals. These scavengers were effective to extinguish AOS from the medium, however the death induction rate was not affected. Mannose, act for hydroxyl radical, had no effect for quenching the AOS and death induction activity. The other scavengers, such as histidine, a scavenger for hydroxyl radicals, dimethylfran for singlet oxygen, and diphenyleneiodonium chloride that is known as inhibitor of NADPH oxidase, functioned as a poison to destroy the tobacco BY-2 cells while none of cryptogein was added to the medium. These results indicate that AOS doses not involve in the execution of hypersensitive cell death.
