Subcellular calcium dynamics and organelle perturbations in resistosome-mediated cell death

Area of Science:

• Plant immunity
• Cell biology
• Molecular mechanisms of plant defense

Background:

• Plant nucleotide-binding domain leucine-rich repeat-containing (NLR) proteins function as intracellular immune receptors.
• Activation of NLR proteins leads to the assembly of resistosomes and subsequent plant cell death.
• The precise subcellular events during plant immune cell death execution remain largely uncharacterized.

Purpose of the Study:

• To visualize and characterize the spatiotemporal dynamics of subcellular changes following resistosome activation.
• To elucidate the sequence of organelle and cellular events during plant immune cell death mediated by the NRC4 resistosome.

Main Methods:

• Live-cell imaging techniques to monitor calcium signaling and organelle behavior.
• Visualization of subcellular structural changes in response to NRC4 resistosome activation.
• Analysis of plasma membrane integrity, nuclear morphology, and vacuolar collapse.

Main Results:

• Resistosome activation (NRC4) was associated with membrane enrichment and calcium influx.
• A sequential cascade of organelle disruption was observed: mitochondria and plastids, followed by endoplasmic reticulum fragmentation.
• Cytoskeleton depolymerization preceded the loss of plasma membrane integrity, nuclear shrinkage, and vacuolar collapse, marking terminal cell death.

Conclusions:

• The study reveals a detailed spatiotemporally resolved cascade of subcellular events downstream of plant NLR resistosome activation.
• These findings provide mechanistic insights into the execution phase of plant immune cell death.
• Understanding these processes is crucial for dissecting plant immune responses and developing disease resistance strategies.