Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1999 Apr;119(4):1233-42.
doi: 10.1104/pp.119.4.1233.

The relationship between photosynthesis and a mastoparan-induced hypersensitive response in isolated mesophyll cells

LJ Allen  1 , KB MacGregor, RS Koop, DH Bruce, J Karner, AW Bown
Affiliations

The relationship between photosynthesis and a mastoparan-induced hypersensitive response in isolated mesophyll cells

LJ Allen et al. Plant Physiol. 1999 Apr.

Abstract

The G-protein activator mastoparan (MP) was found to elicit the hypersensitive response (HR) in isolated Asparagus sprengeri mesophyll cells at micromolar concentrations. The HR was characterized by cell death, extracellular alkalinization, and an oxidative burst, indicated by the reduction of molecular O2 to O2. To our knowledge, this study was the first to monitor photosynthesis during the HR. MP had rapid and dramatic effects on photosynthetic electron transport and excitation energy transfer as determined by variable chlorophyll a fluorescence measurements. A large increase in nonphotochemical quenching of chlorophyll a fluorescence accompanied the initial stages of the oxidative burst. The minimal level of fluorescence was also quenched, which suggests the origin of this nonphotochemical quenching to be a decrease in the antenna size of photosystem II. In contrast, photochemical quenching of fluorescence decreased dramatically during the latter stages of the oxidative burst, indicating a somewhat slower inhibition of photosystem II electron transport. The net consumption of O2 and the initial rate of O2 uptake, elicited by MP, were higher in the light than in the dark. These data indicate that light enhances the oxidative burst and suggest a complex relationship between photosynthesis and the HR.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Sample of PAM chlorophyll a fluorescence yield from a suspension of isolated asparagus mesophyll cells. AL, Actinic light; MB, measuring beam; SF, saturating flash.
Figure 2
Figure 2
Cell viability as a function of MP concentration. Two-milliliter cell suspensions containing 12 × 106 cells were incubated with either 0, 0.25, 2.5, or 25 μm MP. After 16 min of incubation with MP, the cells were incubated with Evan's blue dye for assessment of viability. Percentage cell death represents the mean of three experiments. se bars are shown.
Figure 3
Figure 3
Individual cell viability assayed with Evan's blue dye and fluorescein diacetate. Two 2.5-mL cell suspensions, each containing 10 × 106 cells, were incubated for 16 min with and without 25 μm MP, respectively. Cells were then incubated with fluorescein diacetate in conjunction with Evan's blue dye. Photographs were taken of the same fields of view under both bright and dark fields. These photographs represent control cells under bright (A) and dark (B) fields, and MP-treated cells under bright (C) and dark (D) fields.
Figure 4
Figure 4
The effect of MP and Mas17 on the pH of the incubating medium. The pH of suspensions containing 4.5 × 106 cells in 3 mL of 1 mm CaSO4 was adjusted to approximately 5.0. A, The addition of 13.2 μm MP and two aliquots of 0.10 n HCl (for back-titration) are indicated by arrows. B, The addition of 13.2 μm Mas17 is indicated by an arrow. This figure is a representative of five runs.
Figure 5
Figure 5
The effect of MP concentration on O2 consumption in the light. This figure shows O2 consumption measurements compiled from five separate PAM experiments. In each experiment 2 mL of 5 mm Mes and 1 mm CaSO4, pH 6.0, contained 3 × 106 cells. Aliquots of MP were added to give the concentrations indicated.
Figure 6
Figure 6
The effect of Mas7 on O2⋅− production. Three million cells were incubated in 330 mL of 1 mm CaSO4, pH 5.5, for 5 min. Arrow 1 indicates the addition of 5 μm Mas7 to the cell suspension. Arrow 2 indicates transfer of 200 μL of the cell suspension to the luminometer cuvette. Arrow 3 indicates an artifact due to stray light detected by the photomultiplier as the cuvette is inserted into the luminometer. This figure is a representative of six runs.
Figure 7
Figure 7
The effect of Mas7 on chlorophyll a fluorescence yield and O2 level in the light. Two milliliters of 5 mm Mes and 1 mm CaSO4, pH 6.0, contained 3 × 106 cells. Far-red light (FR), actinic light (AL), 22 μm MP, and O2 were added (↑) or removed (↓) as indicated. The inset represents relative fluorescence immediately before and after Mas7 addition. This figure is a representative of 20 runs.
Figure 8
Figure 8
The effect of Mas7 on qP and qN, respectively over time. Values of qP and qN shown were calculated from one representative trial. Actinic light (AL) and 22 μm Mas7 were administered as indicated by the arrows.
Figure 9
Figure 9
The effect of Mas7 on chlorophyll a fluorescence yield and O2 level in the dark. Two milliliters of 5 mm Mes and 1 mm CaSO4, pH 6.0, contained 3 × 106 cells. Cell suspensions were not illuminated with actinic light. Far-red light (FR), 22 μm MP, and O2 were added (↑) or removed (↓) as indicated. This figure is a representative of 10 runs.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Atkinson MM, Huang J-S, Knopp JA. The hypersensitive reaction of tobacco to Pseudomonas syringae pv. pisi. Activation of a plasmalemma K+/H+ exchange mechanism. Plant Physiol. 1985;79:843–847. - PMC - PubMed
    1. Boller T (1989) Primary signals and second messengers in the reaction of plants to pathogens. In WF Boss, DJ Morré, eds, Second Messengers in Plant Growth and Development. Alan R. Liss, New York, pp 227–255
    1. Bolwell GP, Butt VS, Davies DR, Zimmerlin A. The origin of the oxidative burst in plants. Free Radical Research. 1995;23:517–532. - PubMed
    1. Bruce D, Samson G, Carpenter C. The origins of nonphotochemical quenching of chlorophyll fluorescence in photosynthesis: direct quenching by P680+ in PSII enriched membranes at low pH. Biochemistry. 1997;36:749–755. - PubMed
    1. Chandra S, Heinstein PF, Low PS. Activation of phospholipase A by plant defense elicitors. Plant Physiol. 1996;110:979–986. - PMC - PubMed

LinkOut - more resources