Stress-induced chloroplast degradation in Arabidopsis is regulated via a process independent of autophagy and senescence-associated vacuoles.
Songhu WangEduardo BlumwaldPublished in: The Plant cell (2014)
Two well-known pathways for the degradation of chloroplast proteins are via autophagy and senescence-associated vacuoles. Here, we describe a third pathway that was activated by senescence- and abiotic stress-induced expression of Arabidopsis thaliana CV (for chloroplast vesiculation). After targeting to the chloroplast, CV destabilized the chloroplast, inducing the formation of vesicles. CV-containing vesicles carrying stromal proteins, envelope membrane proteins, and thylakoid membrane proteins were released from the chloroplasts and mobilized to the vacuole for proteolysis. Overexpression of CV caused chloroplast degradation and premature leaf senescence, whereas silencing CV delayed chloroplast turnover and senescence induced by abiotic stress. Transgenic CV-silenced plants displayed enhanced tolerance to drought, salinity, and oxidative stress. Immunoprecipitation and bimolecular fluorescence complementation assays demonstrated that CV interacted with photosystem II subunit PsbO1 in vivo through a C-terminal domain that is highly conserved in the plant kingdom. Collectively, our work indicated that CV plays a crucial role in stress-induced chloroplast disruption and mediates a third pathway for chloroplast degradation. From a biotechnological perspective, silencing of CV offers a suitable strategy for the generation of transgenic crops with increased tolerance to abiotic stress.
Keyphrases
- stress induced
- arabidopsis thaliana
- oxidative stress
- transcription factor
- dna damage
- endoplasmic reticulum stress
- signaling pathway
- poor prognosis
- long non coding rna
- microbial community
- bone marrow
- single molecule
- high throughput
- ischemia reperfusion injury
- single cell
- binding protein
- genome wide identification
- quantum dots
- heat shock protein