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Markers for hypersensitive response and senescence show distinct patterns of expression
D Pontier1, S Gan, R M Amasino
1Center for Agricultural Molecular Biology, Rutgers, The State University of New Jersey, Cook College, New Brunswick, 08901-0231, USA.
Plant Molecular Biology
|June 25, 1999
Summary
Plant programmed cell death (PCD) involves distinct pathways. This study shows hypersensitive response (HR) and senescence markers are mostly specific, though HR may trigger neighboring cell senescence.
Area of Science:
- Plant molecular biology
- Plant pathology
- Cellular biology
Background:
- Programmed cell death (PCD) is crucial for plant development and defense, observed in processes like organogenesis and the hypersensitive response (HR) to pathogens.
- While biochemical and morphological aspects of plant cell death are known, the relationships between different PCD types, such as HR and senescence, are not fully understood.
- Specific molecular markers are used to study PCD, but their coordinated induction across different cell death pathways requires investigation.
Purpose of the Study:
- To investigate the coordinated induction of two hypersensitive response (HR) cell death markers (HIN1 and HSR203J) and a senescence marker (SAG12) in plants.
- To determine if these markers exhibit distinct spatial and temporal activation patterns during HR and senescence.
- To characterize abiotic-induced cell death, specifically copper-induced cell death, in relation to known PCD pathways.
Main Methods:
- Analysis of the spatial and temporal expression patterns of HIN1, HSR203J, and SAG12 during plant hypersensitive response (HR) and senescence.
- Examination of potential cross-talk between HR and senescence pathways using these molecular markers.
- Assessment of copper-induced cell death using the selected PCD markers to compare it with HR.
Main Results:
- Evidence suggests some cross-talk between HR and senescence pathways, but the spatial and temporal activation of HIN1, HSR203J, and SAG12 are distinct during HR and senescence.
- The markers HIN1, HSR203J, and SAG12 demonstrate relative specificity for different plant cell death programs.
- A senescence-like process was observed at the periphery of HR necrotic lesions, indicating a potential signaling mechanism where HR-induced cell death triggers senescence in adjacent cells.
- Copper-induced cell death in plants shares similarities with HR-induced cell death, as indicated by the expression of these markers.
Conclusions:
- The molecular markers HIN1, HSR203J, and SAG12 are largely specific to distinct plant cell death pathways like HR and senescence.
- HR-induced cell death may release signals that induce senescence in neighboring cells, potentially forming a secondary barrier against pathogens.
- Abiotic-induced cell death, such as that caused by copper, exhibits characteristics similar to HR-induced cell death in plants.