Difference between revisions of "Os03g0302900"
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===Function=== | ===Function=== | ||
===Mutation=== | ===Mutation=== | ||
| − | * Characterization of the ssd1 mutant. The ssd1 mutant was screened from the Tos17 mutant library, which is a mutant population induced by the Tos17 retrotransposon.23) In the progeny of heterozygous plants, the segregation ratio of the normal phenotype to the dwarf was 90:31, which corresponded to the expected 3:1 segregation ratio of a single recessive gene ( | + | * Characterization of the ssd1 mutant. The ssd1 mutant was screened from the Tos17 mutant library, which is a mutant population induced by the Tos17 retrotransposon.23) In the progeny of heterozygous plants, the segregation ratio of the normal phenotype to the dwarf was 90:31, which corresponded to the expected 3:1 segregation ratio of a single recessive gene (χ2 ¼ 0.003). The dwarf phenotype in rice is generally caused by a reduction in culm length. Based on the elongation pattern of internodes, rice dwarf mutants are classified into six types: N-, dn-, dm-, d6-, nl-, and sh-type.24) Of these, the dn-type is defined by reduction in internodes length in the same proportion to the WT. ssd1 exhibited a reduction in the length of all internodes in the same proportion as in the WT, which is characteristic of the dn-type dwarf (Fig. 2A), with severe dwarf and wide, dark green leaves (Fig. 1A, B). Culm length of the mutant at harvest was about 17 cm, whereas the WT grew to about 90 cm (Figs. 1A, B and 2A). Elongation of the seminal and crown roots was also inhibited in the mutant (Figs. 1E and 2B), and the development of floral organs was also impaired in ssd1. Rice flowers are composed of four kinds of glumes, two rudimentary glumes, two empty glumes, lemma and palea, and three kinds of floral organs, two lodicules, six stamens, and one pistil.25) The ssd1 glumes were shorter than that of the WT (Fig. 1C, D). The ssd1 flowers also developed short anthers and filaments (Fig. 1F) and short, shrunken stigma (Fig. 1G). Some pistils developed three stigmas (Fig. 1G). These observations suggest that SSD1 has a fundamental role in cell division and/or elongation in various organs. |
[[File:Os03g0302900-1.png|center|thumb|400px|'''Fig. 1. Morphological characterization of the ssd1 mutant.''' '' <ref name="ref1" />.'']] | [[File:Os03g0302900-1.png|center|thumb|400px|'''Fig. 1. Morphological characterization of the ssd1 mutant.''' '' <ref name="ref1" />.'']] | ||
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[[File:Os03g0302900-2.png|center|thumb|400px|'''Fig. 2. Lengths of panicle, internodes, and seminal roots.''' '' <ref name="ref1" />.'']] | [[File:Os03g0302900-2.png|center|thumb|400px|'''Fig. 2. Lengths of panicle, internodes, and seminal roots.''' '' <ref name="ref1" />.'']] | ||
| − | * Cell morphology of ssd1 leaves. Usually, dwarf is caused by a defect in cell division and/or elongation. To clarify which defect causes dwarf phenotype in ssd1 mutant, we observed the microscopic structure of ssd1 leaves. In the WT, cell | + | * Cell morphology of ssd1 leaves. Usually, dwarf is caused by a defect in cell division and/or elongation. To clarify which defect causes dwarf phenotype in ssd1 mutant, we observed the microscopic structure of ssd1 leaves. In the WT, cell files that were well organized in a longitudinal manner were observed (Fig. 3A). In contrast, in ssd1, longitudinally longitudinally arranged cells were not well organized and the cells were enlarged and distorted, leading to a disorganized cell files (Fig. 3B). Moreover, abnormality in the shape and size of cells were observed in ssd1. In the WT, only rectangular cells were observed (Fig. 3A), but trapezoidal, triangular, circular, and diamond-shaped cells were found in ssd1 (Fig. 3B, arrowheads). These abnormal cell shapes and disorganized cell arrangements are probably caused by a defect in synchronous division in these cells. In fact, the transverse division of cells was often slanted in the mutant (Fig. 3B), whereas this abnormal division pattern was not observed in the WT (Fig. 3A). |
[[File:Os03g0302900-3.png|center|thumb|400px|'''Fig. 3. Structure of cells in the leaf sheath of ssd1. (A) and (B) Epidermal cell morphology of Nipponbare and ssd1, respectively. Arrowheads in B indicate cells with abnormal shape and size. Bar ¼ 50 mm.''' '' <ref name="ref1" />.'']] | [[File:Os03g0302900-3.png|center|thumb|400px|'''Fig. 3. Structure of cells in the leaf sheath of ssd1. (A) and (B) Epidermal cell morphology of Nipponbare and ssd1, respectively. Arrowheads in B indicate cells with abnormal shape and size. Bar ¼ 50 mm.''' '' <ref name="ref1" />.'']] | ||
Revision as of 07:04, 1 August 2016
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Contents
Annotated Information
Function
Mutation
- Characterization of the ssd1 mutant. The ssd1 mutant was screened from the Tos17 mutant library, which is a mutant population induced by the Tos17 retrotransposon.23) In the progeny of heterozygous plants, the segregation ratio of the normal phenotype to the dwarf was 90:31, which corresponded to the expected 3:1 segregation ratio of a single recessive gene (χ2 ¼ 0.003). The dwarf phenotype in rice is generally caused by a reduction in culm length. Based on the elongation pattern of internodes, rice dwarf mutants are classified into six types: N-, dn-, dm-, d6-, nl-, and sh-type.24) Of these, the dn-type is defined by reduction in internodes length in the same proportion to the WT. ssd1 exhibited a reduction in the length of all internodes in the same proportion as in the WT, which is characteristic of the dn-type dwarf (Fig. 2A), with severe dwarf and wide, dark green leaves (Fig. 1A, B). Culm length of the mutant at harvest was about 17 cm, whereas the WT grew to about 90 cm (Figs. 1A, B and 2A). Elongation of the seminal and crown roots was also inhibited in the mutant (Figs. 1E and 2B), and the development of floral organs was also impaired in ssd1. Rice flowers are composed of four kinds of glumes, two rudimentary glumes, two empty glumes, lemma and palea, and three kinds of floral organs, two lodicules, six stamens, and one pistil.25) The ssd1 glumes were shorter than that of the WT (Fig. 1C, D). The ssd1 flowers also developed short anthers and filaments (Fig. 1F) and short, shrunken stigma (Fig. 1G). Some pistils developed three stigmas (Fig. 1G). These observations suggest that SSD1 has a fundamental role in cell division and/or elongation in various organs.
Fig. 1. Morphological characterization of the ssd1 mutant. [1].
Fig. 2. Lengths of panicle, internodes, and seminal roots. [1].
- Cell morphology of ssd1 leaves. Usually, dwarf is caused by a defect in cell division and/or elongation. To clarify which defect causes dwarf phenotype in ssd1 mutant, we observed the microscopic structure of ssd1 leaves. In the WT, cell files that were well organized in a longitudinal manner were observed (Fig. 3A). In contrast, in ssd1, longitudinally longitudinally arranged cells were not well organized and the cells were enlarged and distorted, leading to a disorganized cell files (Fig. 3B). Moreover, abnormality in the shape and size of cells were observed in ssd1. In the WT, only rectangular cells were observed (Fig. 3A), but trapezoidal, triangular, circular, and diamond-shaped cells were found in ssd1 (Fig. 3B, arrowheads). These abnormal cell shapes and disorganized cell arrangements are probably caused by a defect in synchronous division in these cells. In fact, the transverse division of cells was often slanted in the mutant (Fig. 3B), whereas this abnormal division pattern was not observed in the WT (Fig. 3A).
Fig. 3. Structure of cells in the leaf sheath of ssd1. (A) and (B) Epidermal cell morphology of Nipponbare and ssd1, respectively. Arrowheads in B indicate cells with abnormal shape and size. Bar ¼ 50 mm. [1].
Expression Pattern
Evolution
Subcellular localization
Labs working on this gene
- Bioscience and Biotechnology Center, Nagoya University, Aichi, Japan.
- Division of Genome and Biodiversity Research, National Institute of Agrobiological Sciences, Ibaraki, Japan.
References
- ↑ 1.0 1.1 1.2 Asano K, Miyao A, Hirochika H, Kitano H, Matsuoka M, Ashikari M. SSD1, which encodes a plant-specific novel protein, controls plant elongation by regulating cell division in rice. Proc Jpn Acad Ser B Phys Biol Sci. 2010;86(3):265-73. PubMed PMID: 20228626; PubMed Central PMCID: PMC3417851.
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