Measurement of stress-induced Ca2+ pulses in single aequorin-transformed tobacco cells

S. G. Cessna, M. A. Messerli, K. R. Robinson, Philip Low

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Signaling patterns measured in large cell populations are the sum of differing signals from separate cells, and thus, the detailed kinetics of Ca2+ pulses can often be masked. In an effort to evaluate whether the cytosolic Ca2+ pulses previously reported in populations of elicitor- and stress-stimulated tobacco cells accurately represent the pulses that occur in individual cells, a study of single cell Ca2+ fluxes in stress-stimulated tobacco cells was undertaken. Individual aequorin-transformed cells were isolated from a tobacco suspension culture and placed directly on a sensitive photo-multiplier tube mounted in a dark chamber. Ca2+-dependent luminescence was then monitored after stimulation with hypo- or hyper-osmotic shock, cold shock, or defense elicitors (oligogalacturonic acid and harpin). Hypo-osmotic shock induced a biphasic Ca2+ transient in 67% of the single cells tested that exhibited similar kinetics to the biphasic pulses measured repeatedly in 1 ml cell suspensions. In contrast, 33% of the stimulated cells displayed Ca2+ flux patterns that were not previously seen in cell suspension studies. Additionally, because only 29% of the cells tested responded with measurable Ca2+ pulses to oligogalacturonic acid and 33% to the harpin protein, we conclude that not all cells in a suspension are simultaneously sensitive to stimulation with defense elicitors. In contrast, all cells tested responded with an immediate Ca2+ influx after cold or hyperosmotic shock. We conclude that in many cases the Ca2+ signaling patterns of single cells are accurately represented in the signaling patterns of large populations, but that single cell measurements are still required to characterize the Ca2+ fluxes of the less prominent cell populations.

Original languageEnglish (US)
Pages (from-to)151-156
Number of pages6
JournalCell Calcium
Volume30
Issue number3
DOIs
StatePublished - Jan 1 2001

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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