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Isolation and Analysis of Arabidopsis Mutants with Altered Leaf Thickness or Leaf Length
https://ir.soken.ac.jp/records/1393
https://ir.soken.ac.jp/records/1393f89e7aa6-f184-43b4-8e55-2e7f21f40234
| 名前 / ファイル | ライセンス | アクション |
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要旨・審査要旨 (284.1 kB)
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本文 (2.2 MB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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| 公開日 | 2010-02-22 | |||||
| タイトル | ||||||
| タイトル | Isolation and Analysis of Arabidopsis Mutants with Altered Leaf Thickness or Leaf Length | |||||
| タイトル | ||||||
| タイトル | Isolation and Analysis of Arabidopsis Mutants with Altered Leaf Thickness or Leaf Length | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||
| 資源タイプ | thesis | |||||
| 著者名 |
成田, 典之
× 成田, 典之 |
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| フリガナ |
ナリタ, ノリユキ
× ナリタ, ノリユキ |
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| 著者 |
NARITA, Noriyuki
× NARITA, Noriyuki |
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| 学位授与機関 | ||||||
| 学位授与機関名 | 総合研究大学院大学 | |||||
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| 学位名 | 博士（理学） | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | 総研大甲第876号 | |||||
| 研究科 | ||||||
| 値 | 生命科学研究科 | |||||
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| 値 | X2 分子生物機構論専攻 | |||||
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| 学位授与年月日 | 2005-03-24 | |||||
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| 値 | 2004 | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | Leaf shape in wild plants has diversely evolved from ancient times. A lot of researchers have challenged to elucidate mechanisms of the evolutional dynamics in plant leaf shape. Several studies carried out by using genetic model plants, such as Arabidopsis thaliana, Antirrhinum majus or Lycopersicon esculentum revealed a part of the genetic basis of variation in leaf shape. However, to get the general picture of evolutional dynamics in plant leaf shape, more studies are needed. We can divide things to three dimensions called length, width and height. Thus, he thought that three-dimensional classification of leaves would help to elucidate leaf-shape diversity. In previous studies, two classes of mutants, namely angustifolia (an) type and rotundifolia (rot) type with a specific alteration in either width or length of the leaf blade were identified in Arabidopsis. In both an and rot3 mutants, the leaf shape alteration is caused by the altered cell shape. However, the leaf dwarfism or the diversity of leaf shape is mainly caused by the variation of the cell number in wild plants. Therefore, he analyzed a dominant mutant, rotundifolia4-1D (rot4-1D), which possessed short leaves and floral organs caused by reduction of the cell number. On the other hand, variation of leaf thickness is mainly due to alteration of cell volume and/or cell number in wild plants. He have also isolated a mutant, working number N692, which possessed thick leaves caused by unusual cell expansion in the leaf thickness direction in Arabidopsis. <br /> In rot4-1D, anatomical observations showed that the altered leaf shape is caused by reduced cell proliferation specifically in the longtitudinal (proximal-distal) axis of the leaf, suggesting that the ROT4 gene controls polar cell proliferation in lateral organs. The ROT4 gene encodes a novel small peptide consisting of 53 amino acid residues. ROT4 open reading frame had not been identified in the Arabidopsis genome annotation. He cloned ROT4 full-length cDNA and registered it to the GenBank as accession number AB107209. ROT4 mRNA accumulates at a higher level in rot4-1D compared to wild type. Over-expression of a ROT4-green fluorescence protein (GFP) fusion protein in transgenic plants recapitulated the rot4-1D phenotype suggesting that ROT4 acts to restrict cell proliferation. The ROT4-GEP fusion protein localized to the plasma membrane when expressed in transgenic Arabidopsis plants. Database search and phylogenetic analysis indicate that ROT4 defines a novel, seed plant-specific family of small peptides with 22 members in Arabidopsis, ROT FOUR LIKE1-22 (RTFL1-22), and all RTFL members share a conserved 29 amino acid domain, the RTF domain. ROT4 contains N-terminal region (16 amino acid residues), RTF domain and C-terminal region (8 amino acid residues), and over-expression of the ROT4 truncated N-terminal region or C-terminal region was sufficient to confer a rot4-1D phenotype. Loss-of-function mutations in several RTFL genes were aphenotypic in Arabidopsis or Oryza sativa suggesting that there may be some functional redundancy among family members. RT-PCR analysis revealed that ROT4 is expressed in the shoot apex and young leaves of wild-type plants, consistent with a role for ROT4 in controlling polarity-dependent cell proliferation during wild-type leaf morphogenesis.<br /> On the other hand, mutants with only changed leaf thickness had not been isolated. Therefore, as the first step to study thickness control in leaves, he developed an instrument, called Leaf Thickness Measurement Instrument (LTMI) that can measure the thickness of Arabidopsis living leaves reproducibly by a laser displacement sensor. The conventional measurement method requires several complicated and time consuming steps, such as fixation, embedding, slicing of the samples by microtome and finally observation under microscope. These steps can be omitted by using LTMI. Thick-leaved mutants were screened from a T-DNA activation-tagged library of C24 by using LTMI. By screening more than 2000 lines, he isolated three mutants N692, N865 and N091 with thicker or thinner leaves than wild type. He mainly analyzed N692 which has the most altered leaf thickness among the three mutants. The thickness of N692 leaves was 158 ± 10μm, while that of wild-type C24 leaves was 126 ± 6μm. In addition, leaves of N692 are tight, while those of wild type are waved and curly. Moreover, the stem of N692 is thicker than that of wild type. Anatomical analysis showed that palisade cells of N692 expand isotropically and number of the cells per leaf is reduced. As a result, the leaf blade area of N692 is equal to that of wild type. It is thought that compensation occurs in leaf area but not occurs in leaf thickness direction. A mutant which has such phenotype is unprecedent. <br /> Recently, movement of an application from outcome of model plants to properties of other wild plants has occurred in morphogenesis and related fields. In addition to an-like and rot-like mutants, by the isolation of N692, a description with three-dimensional geometry has been possible. It is thought analysis of seed-plant specific ROT4 and RTFL genes is suitable to apply for estimation of leaf shape in wild plants. Building on our previous success in the identification of AN and ROT3 genes, the present study of rot4-1D and N692 will possibly help to illustrate the variety of leaf shape in wild plants. | |||||
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| 値 | 有 | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | application/pdf | |||||
