Involvement of mitochondria and metacaspase elevation in harpin Pss-induced cell death of Saccharomyces cerevisiae.
Expression of a proteinaceous elicitor harpin(Pss,) encoded by hrpZ of Pseudomonas syringae pv. syringae 61, under GAL1 promoter in Saccharomyces cerevisiae Y187 resulted in galactose-inducible yeast cell death (YCD). Extracellular treatment of harpin did not affect the growth of yeast. The observed YCD was independent of the stage of cell cycle. "Petite" mutant of S. cerevisiae Y187 pYEUT-hrpZ was insensitive to cell death indicating the involvement of mitochondria in this YCD. Loss in mitochondrial potential, but no leakage of Cytochrome c from mitochondria into the cytosol, were notable features in harpin(Pss)-induced YCD. Cyclosporin A had no effect on hrpZ expressing yeast cells, further confirmed that there was no release of Cytochrome c. Elevation of caspase activity has been reported for the first time in this form of cell death induced by harpin expression. Release of reactive oxygen species and clear loss of membrane integrity were evident with the absence of nuclear fragmentation and chromosomal condensation, while annexin V and propidium iodide staining showed features typical of necrosis.
Sripriya
Paranthaman
P
Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Andhra Pradesh, India.
Vedantam
Lakshmi Vasudev
LV
Podile
Appa Rao
AR
D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D045304:Cytochromes c; D008928:Mitochondria / Q000378:metabolism*; D044224:Pseudomonas syringae / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000648:ultrastructure
D001425:Bacterial Outer Membrane Proteins; D017382:Reactive Oxygen Species; C087295:HrpZ protein, Pseudomonas syringae; D045304:Cytochromes c; D020169:Caspases