Identification of the bacterial alarmone guanosine 5′-diphosphate 3′-diphosphate (ppGpp) in plants
AUTOR(ES)
Takahashi, Kosaku
FONTE
National Academy of Sciences
RESUMO
Stringent control mediated by the bacterial alarmone guanosine 5′-diphosphate 3′-diphosphate (ppGpp) is a key regulatory process governing bacterial gene expression. By devising a system to measure ppGpp in plants, we have been able to identify ppGpp in the chloroplasts of plant cells. Levels of ppGpp increased markedly when plants were subjected to such biotic and abiotic stresses as wounding, heat shock, high salinity, acidity, heavy metal, drought, and UV irradiation. Abrupt changes from light to dark also caused a substantial elevation in ppGpp levels. In vitro, chloroplast RNA polymerase activity was inhibited in the presence of ppGpp, demonstrating the existence of a bacteria-type stringent response in plants. Elevation of ppGpp levels was elicited also by treatment with plant hormones jasmonic acid, abscisic acid, and ethylene, but these effects were blocked completely by another plant hormone, indole-3-acetic acid. On the basis of these findings, we propose that ppGpp plays a critical role in systemic plant signaling in response to environmental stresses, contributing to the adaptation of plants to environmental changes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=384739Documentos Relacionados
- Guanosine 5'-diphosphate 3'-diphosphate (ppGpp): positive effector for histidine operon transcription and general signal for amino-acid deficiency.
- Guanosine 3',5'-bispyrophosphate (ppGpp) synthesis in cells of Escherichia coli starved for Pi.
- Energy deprivation and guanosine 5'-diphosphate 3'-diphosphate synthesis in cyanobacteria.
- Direct correlation between overproduction of guanosine 3',5'-bispyrophosphate (ppGpp) and penicillin tolerance in Escherichia coli.
- Mechanism of the in vitro breakdown of guanosine 5'-diphosphate 3'-diphosphate in Escherichia coli.