Although plants are exposed to a great number of pathogens, they usually defend themselves by triggering mechanisms able to limit disease development. Alongside signalling events common to most such incompatible interactions, modifications of plasma membrane (PM) physical properties could be new players in the cell transduction cascade. Different pairs of elicitors (cryptogein, oligogalacturonides, and flagellin) and plant cells (tobacco and Arabidopsis) were used to address the issue of possible modifications of plant PM biophysical properties induced by elicitors and their links to other events of the defence signalling cascade. We observed an increase of PM order whatever the elicitor/plant cell pair used, provided that a signalling cascade was induced. Such membrane modification is dependent on the NADPH oxidase-mediated reactive oxygen species production. Moreover, cryptogein, which is the sole elicitor able to trap sterols, is also the only one able to trigger an increase in PM fluidity. The use of cryptogein variants with altered sterol-binding properties confirms the strong correlation between sterol removal from the PM and PM fluidity enhancement. These results propose PM dynamics as a player in early signalling processes triggered by elicitors of plant defence.
- Klíčová slova
- Cryptogein mutants, elicitors, fluidity, membrane order, plant defence, plasma membrane, reactive oxygen species, signalling.,
- MeSH
- Arabidopsis fyziologie MeSH
- buněčná membrána metabolismus fyziologie MeSH
- fluidita membrány fyziologie MeSH
- fluorescenční mikroskopie MeSH
- fluorescenční spektrometrie MeSH
- konfokální mikroskopie MeSH
- nemoci rostlin MeSH
- odolnost vůči nemocem fyziologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- signální transdukce fyziologie MeSH
- tabák fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- reaktivní formy kyslíku MeSH
Plant NADPH oxidases, also known as respiratory burst oxidase homologues (RBOHs), have been identified as a major source of reactive oxygen species (ROS) during plant-microbe interactions. The subcellular localization of the tobacco (Nicotiana tabacum) ROS-producing enzyme RBOHD was examined in Bright Yellow-2 cells before and after elicitation with the oomycete protein cryptogein using electron and confocal microscopy. The plasma membrane (PM) localization of RBOHD was confirmed and immuno-electron microscopy on purified PM vesicles revealed its distribution in clusters. The presence of the protein fused to GFP was also seen in intracellular compartments, mainly Golgi cisternae. Cryptogein induced, within 1h, a 1.5-fold increase in RBOHD abundance at the PM and a concomitant decrease in the internal compartments. Use of cycloheximide revealed that most of the proteins targeted to the PM upon elicitation were not newly synthesized but may originate from the Golgi pool. ROS accumulation preceded RBOHD transcript- and protein-upregulation, indicating that ROS resulted from the activation of a PM-resident pool of enzymes, and that enzymes newly addressed to the PM were inactive. Taken together, the results indicate that control of RBOH abundance and subcellular localization may play a fundamental role in the mechanism of ROS production.
- Klíčová slova
- BY-2 cells, Nicotiana tabacum, cryptogein, protein trafficking, protein trafficking., reactive oxygen species, respiratory burst oxidase homolog D (RBOHD),
- MeSH
- buněčná membrána metabolismus MeSH
- fungální proteiny metabolismus MeSH
- konfokální mikroskopie MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- NADPH-oxidasy genetika metabolismus MeSH
- Phytophthora fyziologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rostlinné proteiny genetika metabolismus MeSH
- tabák genetika metabolismus mikrobiologie MeSH
- transmisní elektronová mikroskopie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- fungální proteiny MeSH
- NADPH-oxidasy MeSH
- reaktivní formy kyslíku MeSH
- rostlinné proteiny MeSH
