Limits...
The Arabidopsis minE mutation causes new plastid and FtsZ1 localization phenotypes in the leaf epidermis.

Fujiwara MT, Kojo KH, Kazama Y, Sasaki S, Abe T, Itoh RD - Front Plant Sci (2015)

Bottom Line: Plastids in the leaf epidermal cells of plants are regarded as immature chloroplasts that, like mesophyll chloroplasts, undergo binary fission.In atminE1, the size and shape of epidermal plastids varied widely, which contrasts with the plastid phenotype observed in atminE1 mesophyll cells.Observation of an atminE1 transgenic line harboring an AtMinE1 promoter::AtMinE1-yellow fluorescent protein fusion gene confirmed the expression and plastidic localization of AtMinE1 in the leaf epidermis.

View Article: PubMed Central - PubMed

Affiliation: RIKEN Nishina Center Saitama, Japan ; Graduate School of Science and Technology, Sophia University Tokyo, Japan.

ABSTRACT
Plastids in the leaf epidermal cells of plants are regarded as immature chloroplasts that, like mesophyll chloroplasts, undergo binary fission. While mesophyll chloroplasts have generally been used to study plastid division, recent studies have suggested the presence of tissue- or plastid type-dependent regulation of plastid division. Here, we report the detailed morphology of plastids and their stromules, and the intraplastidic localization of the chloroplast division-related protein AtFtsZ1-1, in the leaf epidermis of an Arabidopsis mutant that harbors a mutation in the chloroplast division site determinant gene AtMinE1. In atminE1, the size and shape of epidermal plastids varied widely, which contrasts with the plastid phenotype observed in atminE1 mesophyll cells. In particular, atminE1 epidermal plastids occasionally displayed grape-like morphology, a novel phenotype induced by a plastid division mutation. Observation of an atminE1 transgenic line harboring an AtMinE1 promoter::AtMinE1-yellow fluorescent protein fusion gene confirmed the expression and plastidic localization of AtMinE1 in the leaf epidermis. Further examination revealed that constriction of plastids and stromules mediated by the FtsZ1 ring contributed to the plastid pleomorphism in the atminE1 epidermis. These results illustrate that a single plastid division mutation can have dramatic consequences for epidermal plastid morphology, thereby implying that plastid division and morphogenesis are differentially regulated in epidermal and mesophyll plastids.

No MeSH data available.


Related in: MedlinePlus

Various types of plastid morphology and distribution patterns in leaf epidermis of atminE1. (A–H) Images of CFP-labeled plastids in leaf petiole epidermis of 2- or 3-week-old atminE1 seedlings. DIC and chlorophyll fluorescence (Chl magenta-colored) images are also shown. Asterisks indicate plastids with chlorophyll signals only within cells, while double arrowheads indicate cell nuclei. Single arrowheads and boxes represent plastid bulges associated with plastid bodies or stromules and their activated regions, respectively. Inset in (D) is a CFP image of a chlorophyll-positive plastid pair taken using a shorter exposure time. Bars = 10 μm (white) and 100 μm (black). (I) Measurement of plastid morphologies in WT and atminE1. Phenotypes of epidermal plastids in 2-week-old seedlings were classified into three groups, ‘single plastid’, ‘network’ and ‘grape-like’. The former group was further examined with respect to total plastid length. Plastid length was defined as the length of the longest line passing over the plastid area. Since the borders between plastid bodies and stromules were often unclear in atminE1, the plastid length includes the area of stromules (for both WT and atminE1 samples).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4593956&req=5

Figure 3: Various types of plastid morphology and distribution patterns in leaf epidermis of atminE1. (A–H) Images of CFP-labeled plastids in leaf petiole epidermis of 2- or 3-week-old atminE1 seedlings. DIC and chlorophyll fluorescence (Chl magenta-colored) images are also shown. Asterisks indicate plastids with chlorophyll signals only within cells, while double arrowheads indicate cell nuclei. Single arrowheads and boxes represent plastid bulges associated with plastid bodies or stromules and their activated regions, respectively. Inset in (D) is a CFP image of a chlorophyll-positive plastid pair taken using a shorter exposure time. Bars = 10 μm (white) and 100 μm (black). (I) Measurement of plastid morphologies in WT and atminE1. Phenotypes of epidermal plastids in 2-week-old seedlings were classified into three groups, ‘single plastid’, ‘network’ and ‘grape-like’. The former group was further examined with respect to total plastid length. Plastid length was defined as the length of the longest line passing over the plastid area. Since the borders between plastid bodies and stromules were often unclear in atminE1, the plastid length includes the area of stromules (for both WT and atminE1 samples).

Mentions: Next, we examined the plastid morphology in the leaf petiole epidermis of atminE1 in light of their size, number, and distribution within each cell (Figure 3). We found several plastid size, number, and distribution patterns: a single cell could contain only one giant plastid (Figure 3A), one giant plastid coexisting with tiny plastid(s) (Figure 3B), or some plastid bodies connected by stromules, forming a network throughout the entire length of the petiole epidermal cell (Figure 3C; Supplementary Figure S2A). These patterns are basically in agreement with the findings of a previous report on the arc6 mutant (Holzinger et al., 2008). Moreover, we occasionally detected a cell containing dumbbell-shaped, chlorophyll-bearing plastids (Figure 3D), a novel feature of atminE1. In general, only giant plastids, which appeared to be produced via inhibited plastid division, appeared to contain chlorophyll (Figures 2A–C) in the atminE1 epidermis, although there were some exceptions (Figures 2E,J). The existence of dumbbell-shaped, chlorophyll-bearing plastids implies that some of these chlorophyll-containing plastids maintain the capability of proliferation by division.


The Arabidopsis minE mutation causes new plastid and FtsZ1 localization phenotypes in the leaf epidermis.

Fujiwara MT, Kojo KH, Kazama Y, Sasaki S, Abe T, Itoh RD - Front Plant Sci (2015)

Various types of plastid morphology and distribution patterns in leaf epidermis of atminE1. (A–H) Images of CFP-labeled plastids in leaf petiole epidermis of 2- or 3-week-old atminE1 seedlings. DIC and chlorophyll fluorescence (Chl magenta-colored) images are also shown. Asterisks indicate plastids with chlorophyll signals only within cells, while double arrowheads indicate cell nuclei. Single arrowheads and boxes represent plastid bulges associated with plastid bodies or stromules and their activated regions, respectively. Inset in (D) is a CFP image of a chlorophyll-positive plastid pair taken using a shorter exposure time. Bars = 10 μm (white) and 100 μm (black). (I) Measurement of plastid morphologies in WT and atminE1. Phenotypes of epidermal plastids in 2-week-old seedlings were classified into three groups, ‘single plastid’, ‘network’ and ‘grape-like’. The former group was further examined with respect to total plastid length. Plastid length was defined as the length of the longest line passing over the plastid area. Since the borders between plastid bodies and stromules were often unclear in atminE1, the plastid length includes the area of stromules (for both WT and atminE1 samples).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593956&req=5

Figure 3: Various types of plastid morphology and distribution patterns in leaf epidermis of atminE1. (A–H) Images of CFP-labeled plastids in leaf petiole epidermis of 2- or 3-week-old atminE1 seedlings. DIC and chlorophyll fluorescence (Chl magenta-colored) images are also shown. Asterisks indicate plastids with chlorophyll signals only within cells, while double arrowheads indicate cell nuclei. Single arrowheads and boxes represent plastid bulges associated with plastid bodies or stromules and their activated regions, respectively. Inset in (D) is a CFP image of a chlorophyll-positive plastid pair taken using a shorter exposure time. Bars = 10 μm (white) and 100 μm (black). (I) Measurement of plastid morphologies in WT and atminE1. Phenotypes of epidermal plastids in 2-week-old seedlings were classified into three groups, ‘single plastid’, ‘network’ and ‘grape-like’. The former group was further examined with respect to total plastid length. Plastid length was defined as the length of the longest line passing over the plastid area. Since the borders between plastid bodies and stromules were often unclear in atminE1, the plastid length includes the area of stromules (for both WT and atminE1 samples).
Mentions: Next, we examined the plastid morphology in the leaf petiole epidermis of atminE1 in light of their size, number, and distribution within each cell (Figure 3). We found several plastid size, number, and distribution patterns: a single cell could contain only one giant plastid (Figure 3A), one giant plastid coexisting with tiny plastid(s) (Figure 3B), or some plastid bodies connected by stromules, forming a network throughout the entire length of the petiole epidermal cell (Figure 3C; Supplementary Figure S2A). These patterns are basically in agreement with the findings of a previous report on the arc6 mutant (Holzinger et al., 2008). Moreover, we occasionally detected a cell containing dumbbell-shaped, chlorophyll-bearing plastids (Figure 3D), a novel feature of atminE1. In general, only giant plastids, which appeared to be produced via inhibited plastid division, appeared to contain chlorophyll (Figures 2A–C) in the atminE1 epidermis, although there were some exceptions (Figures 2E,J). The existence of dumbbell-shaped, chlorophyll-bearing plastids implies that some of these chlorophyll-containing plastids maintain the capability of proliferation by division.

Bottom Line: Plastids in the leaf epidermal cells of plants are regarded as immature chloroplasts that, like mesophyll chloroplasts, undergo binary fission.In atminE1, the size and shape of epidermal plastids varied widely, which contrasts with the plastid phenotype observed in atminE1 mesophyll cells.Observation of an atminE1 transgenic line harboring an AtMinE1 promoter::AtMinE1-yellow fluorescent protein fusion gene confirmed the expression and plastidic localization of AtMinE1 in the leaf epidermis.

View Article: PubMed Central - PubMed

Affiliation: RIKEN Nishina Center Saitama, Japan ; Graduate School of Science and Technology, Sophia University Tokyo, Japan.

ABSTRACT
Plastids in the leaf epidermal cells of plants are regarded as immature chloroplasts that, like mesophyll chloroplasts, undergo binary fission. While mesophyll chloroplasts have generally been used to study plastid division, recent studies have suggested the presence of tissue- or plastid type-dependent regulation of plastid division. Here, we report the detailed morphology of plastids and their stromules, and the intraplastidic localization of the chloroplast division-related protein AtFtsZ1-1, in the leaf epidermis of an Arabidopsis mutant that harbors a mutation in the chloroplast division site determinant gene AtMinE1. In atminE1, the size and shape of epidermal plastids varied widely, which contrasts with the plastid phenotype observed in atminE1 mesophyll cells. In particular, atminE1 epidermal plastids occasionally displayed grape-like morphology, a novel phenotype induced by a plastid division mutation. Observation of an atminE1 transgenic line harboring an AtMinE1 promoter::AtMinE1-yellow fluorescent protein fusion gene confirmed the expression and plastidic localization of AtMinE1 in the leaf epidermis. Further examination revealed that constriction of plastids and stromules mediated by the FtsZ1 ring contributed to the plastid pleomorphism in the atminE1 epidermis. These results illustrate that a single plastid division mutation can have dramatic consequences for epidermal plastid morphology, thereby implying that plastid division and morphogenesis are differentially regulated in epidermal and mesophyll plastids.

No MeSH data available.


Related in: MedlinePlus