Green fluorescent stroma filled tubules (stromules) emanating from the plastid surface were observed in transgenic plants containing plastid-localized green fluorescent protein (GFP). These transgenic tobacco plants were further investigated by epifluorescence and confocal laser scanning microscopy (CSLM) to identify developmental and/or cell type specific differences in the abundance and appearance of stromules and of plastids. Stromules are rarely seen on chlorophyll-containing plastids in cell types such as trichomes, guard cells or mesophyll cells of leaves. In contrast, they are abundant in tissues that contain chlorophyll-free plastids, such as petal and root. The morphology of plastids in roots and petals is highly dynamic, and plastids are often elongated and irregular. The shapes, size, and position of plastids vary in particular developmental zones of the root. Furthermore, suspension cells of tobacco exhibit stromules on virtually every plastid with two major forms of appearance. The majority of cells show a novel striking ‘octopus- or millipede-like’ structure with plastid bodies clustered around the nucleus and with long thin stromules of up to at least 40 (micro)m length stretching into distant areas of the cell. The remaining cells have plastid bodies distributed throughout the cell with short stromules. Photobleaching experiments indicated that GFP can flow through stromules and that the technique can be used to distinguish interconnected plastids from independent plastids.

REFERENCES

Benfey
P. N.
,
Schiefelbein
J. W.
(
1994
).
Getting to the root of plant development: The genetics of Arabidopsis root formation.
Trends Genet
10
,
84
88
Bourett
T. M.
,
Czymmek
K. J.
,
Howard
R. J.
(
1999
).
Ultrastructure of chloroplast protuberances in rice leaves preserved by high-pressure freezing.
Planta
208
,
472
479
Cerutti
H.
,
Osman
M.
,
Grandoni
P.
,
Jagendorf
A. T.
(
1992
).
A homolog of Escherichia coli Reca protein in plastids of higher plants.
Proc. Nat. Acad. Sci. USA
89
,
8068
8072
Chalfie
M.
,
Tu
Y.
,
Euskirchen
G.
,
Ward
W. W.
,
Prasher
D. C.
(
1994
).
Green fluorescent protein as a marker for gene expression.
Science
263
,
802
805
Charon
J.
,
Launay
J.
,
Carde
J. P.
(
1987
).
Spatial organization and volume density of leucoplasts in pine secretory cells.
Protoplasma
138
,
45
53
Dolan
L.
,
Janmaat
K.
,
Willemsen
V.
,
Linstead
P.
,
Poethig
S.
,
Roberts
K.
,
Scheres
B.
(
1993
).
Cellular organisation of the Arabidopsis thaliana root.
Development
119
,
71
84
Drews
G. N.
,
Beals
T. P.
,
Bui
A. Q.
,
Goldberg
R. B.
(
1992
).
Regional and cell-specific gene expression patterns during petal development.
Plant Cell
4
,
1383
1404
Ehara
T.
,
Osafune
T.
,
Hase
E.
(
1990
).
Interactions between the nucleus and cytoplasmic organelles during the cell cycle of Euglena gracilis in synchronized cultures: IV. An aggregate form of chloroplasts in association with the nucleus appearing prior to chloroplast division.
Exp. Cell Res
190
,
104
112
Haseloff
J.
,
Siemering
K. R.
,
Prasher
D.
,
Hodge
S.
(
1997
).
Removal of a cryptic intron and subcellular localization of green fluorescent protein are required to mark transgenic Arabidopsis plants brightly.
Proc. Nat. Acad. Sci. USA
94
,
2122
2127
Heitz
E.
(
1936
).
Untersuchungen uber den Bau der Plastiden I. Die gerichteten Chlorophyllscheiben der Chloroplasten.
Planta
26
,
134
163
Hermann
G. J.
,
Shaw
J. M.
(
1998
).
Mitochondrial dynamics in yeast.
Annu. Rev. Cell Dev. Biol
14
,
265
303
Horsch
R. B.
,
Fry
J. E.
,
Hoffmann
N. L.
,
Eichholtz
D.
,
Rogers
S. G.
,
Fraley
R. T.
(
1985
).
A simple and general method for transferring genes into plants.
Science
227
,
1229
1231
Hosticka
L. P.
,
Hanson
M. R.
(
1984
).
Induction of plastid mutations in tomatoes by nitrosomethylurea.
J. Hered
75
,
242
246
Kaul
K.
,
Sabharwal
P. S.
(
1971
).
Effects of sucrose and kinetin on growth and chlorophyll synthesis in tobacco-D tissue ultures.
Plant Physiol
47
,
691
695
Köhler
R. H.
,
Cao
J.
,
Zipfel
W. R.
,
Webb
W. W.
,
Hanson
M. R.
(
1997
).
Exchange of protein molecules through connections between higher plant plastids.
Science
276
,
2039
2042
Medgyesy
P.
,
Fejes
E.
,
Maliga
P.
(
1985
).
Interspecific chloroplast recombination in a Nicotiana somatic hybrid.
Proc. Nat. Acad. Sci. USA
82
,
6960
6964
Menzel
D.
(
1994
).
An interconnected plastidom in Acetabularia: Implications for the mechanism of chloroplast motility.
Protoplasma
179
,
166
171
Newcomb
E. H.
(
1967
).
Fine structure of protein-storing plastids in bean root tips.
J. Cell Biol
33
,
143
163
Nishibayashi
S.
,
Kuroiwa
T.
(
1982
).
Behavior of leucoplast nucleoids in the epidermal cell of onion (Allium cepa) bulb.
Protoplasma
110
,
177
184
Osafune
T.
,
Ehara
T.
,
Hase
E.
,
Schiff Jerome
A.
(
1993
).
Stage-dependent association of nuclear and chloroplast DNA molecules through bridges transiently formed between the two organelles in synchronized cells of Euglena gracilis.
J. Electron Microsc
42
,
197
201
Pyke
K. A.
,
Page
A. M.
(
1998
).
Plastid ontogeny during petal development in Arabidopsis.
Plant Physiol
116
,
797
803
Shalla
T. A.
(
1962
).
Assembly and aggregation of tobacco mosaic virus in tomato leaflets.
J. Cell Biol
21
,
253
264
Spencer
D.
,
Wildman
S. G.
(
1962
).
Observations on the structure of grana-containing chloroplasts and a proposed model of chloroplast structure.
Aust. J. Biol. Sci
15
,
599
610
Steffen
K.
(
1964
).
Chromoplastenstudien: I. Der amöboide Chromoplastentyp.
Planta
60
,
506
522
Stickens
D.
,
Verbelen
J. P.
(
1996
).
Spatial structure of mitochondria and ER denotes changes in cell physiology of cultured tobacco protoplasts.
Plant J
9
,
85
92
Suzuki
T.
,
Kawano
S.
,
Sakai
A.
,
Fujie
M.
,
Kuroiwa
H.
,
Nakamura
H.
,
Kuroiwa
T.
(
1992
).
Preferential mitochondrial and plastid DNA synthesis before multiple cell divisions in Nicotiana tabacum.
J. Cell Sci
103
,
831
837
Svab
Z.
,
Maliga
P.
(
1993
).
High-frequency plastid transformation in tobacco by selection for a chimeric aadA gene.
Proc. Nat. Acad. Sci. USA
90
,
913
917
Tobias
C. M.
,
Nasrallah
J. B.
(
1996
).
A S-locus-related gene in Arabidopsis encodes a functional kinase and produces two classes of transcripts.
Plant J
10
,
523
531
Whatley
J. M.
(
1983
).
The ultrastructure of plastids in roots.
Int. Rev. Cytol
85
,
175
220
Wildman
S. G.
,
Hongladarom
T.
,
Honda
S. I.
(
1962
).
Chloroplast and mitochondria in living plant cells: cinematographic studies.
Science
138
,
434
436
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