17 results on '"Itoh, Jun-ichi"'
Search Results
2. Genetic interaction between rice PLASTOCHRON genes and the gibberellin pathway in leaf development.
- Author
-
Mimura, Manaki and Itoh, Jun-Ichi
- Subjects
- *
GIBBERELLIN genetics , *PHENOTYPES , *MOLECULAR genetics , *METABOLISM ,RICE genetics - Abstract
Background: The rice PLASTOCHRON ( PLA) genes PLA1 and PLA2 regulate leaf maturation and the temporal pattern of leaf initiation. Although the function of PLA genes in the leaf initiation process has been analyzed, little is known about how they affect leaf growth. Previously, we suggested that PLA1 and PLA2 function downstream of the gibberellin (GA) signal transduction pathway. In the present study, we examined the phenotype of a double mutant of pla and slender rice 1 ( slr1), which is a constitutive GA response mutant. By analyzing these double mutants, we discuss the relationship between PLA-related and GA-dependent pathways and the possible function of PLA genes in leaf growth. Findings: Single slr1 and pla mutants exhibited elongated and dwarf phenotypes in the vegetative stage, respectively. The stature and leaf size of the pla1/slr1 and pla2/slr1 double mutants were intermediate between those of the pla and slr1 single mutants. However, the effects of slr1 on leaf elongation were markedly suppressed in the pla1 and pla2 mutant backgrounds. On the other hand, the change in cell length in the double mutants was almost the same as that in the single mutants. An expression analysis of genes involved in GA biosynthesis and catabolism indicated that feedback regulation functioned normally in the pla/slr1 double mutants. Conclusions: Our genetic results confirm that PLA genes regulate leaf growth downstream of the GA pathway. Our findings also suggest that PLA1 and PLA2 are partly required for GA-dependent leaf elongation, mainly by affecting cellular proliferation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
3. Rice DECUSSATE controls phyllotaxy by affecting the cytokinin signaling pathway.
- Author
-
Itoh, Jun-ichi, Hibara, Ken-ichiro, Kojima, Mikiko, Sakakibara, Hitoshi, and Nagato, Yasuo
- Subjects
- *
LEAVES , *CYTOKININS , *PLANT cellular signal transduction , *PLANT genes , *PLANT mutation , *APICAL meristems , *GENETIC regulation in plants , *CELL division , *MERISTEMS , *GLUTAMINE , *RICE , *PLANTS - Abstract
Phyllotaxy is defined as the spatial arrangement of leaves on the stem. The mechanism responsible for this extremely regular pattern is one of the most fascinating enigmas in plant biology. In this study, we identified a gene regulating the phyllotactic pattern in rice. Loss-of-function mutants of the DECUSSATE [DEO gene displayed a phyllotactic conversion from normal distichous pattern to decussate. The dec mutants had an enlarged shoot apical meristem with enhanced cell division activity. In contrast to the shoot apical meristem, the size of the root apical meristem in the dec mutants was reduced, and cell division activity was suppressed. These phenotypes indicate that DEC has opposite functions in the shoot apical meristem and root apical meristem. Map-based cloning revealed that DEC encodes a plant-specific protein containing a glutamine-rich region and a conserved motif. Although its molecular function is unclear, the conserved domain is shared with fungi and animals. Expression analysis showed that several type A response regulator genes that act in the cytokinin signaling pathway were down-regulated in the dec mutant. In addition, dec seedlings showed a reduced responsiveness to exogenous cytokinin. Our results suggest that DEC controls the phyllotactic pattern by affecting cytokinin signaling in rice. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. COE1, an LRR-RLK responsible for commissural vein pattern formation in rice.
- Author
-
Sakaguchi, Jun, Itoh, Jun-Ichi, Ito, Yukihiro, Nakamura, Ayako, Fukuda, Hiroo, and Sawa, Shinichiro
- Subjects
- *
RICE , *LEAVES , *VASCULAR system of plants , *NAPHTHALENEACETIC acid , *LEUCINE , *BRASSINOSTEROIDS , *AUXIN - Abstract
Summary Leaf veins have a complex network pattern. Formation of this vein pattern has been widely studied as a model of tissue pattern formation in plants. To understand the molecular mechanism governing the vascular patterning process, we isolated the rice mutant, commissural vein excessive1 ( coe1). The coe1 mutants had short commissural vein (CV) intervals and produced clustered CVs. Application of 1- N-naphthylphthalamic acid and brefeldin A decreased CV intervals, and application of 1-naphthaleneacetic acid increased CV intervals in wild-type rice; however, coe1 mutants were insensitive to these chemicals. COE1 encodes a leucine-rich repeat receptor-like kinase, whose amino acid sequence is similar to that of brassinosteroid-insensitive 1-associated receptor kinase 1 (BAK1), and which is localized at the plasma membrane. Because of the sequence similarity of COE1 to BAK1, we also examined the involvement of brassinosteroids in CV formation. Brassinolide, an active brassinosteroid, decreased the CV intervals of wild-type rice, and brassinazole, an inhibitor of brassinosteroid biosynthesis, increased the CV intervals of wild-type rice, but coe1 mutants showed insensitivity to these chemicals. These results suggest that auxin and brassinosteroids regulate CV intervals in opposite directions, and COE1 may regulate CV intervals downstream of auxin and brassinosteroid signals. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
5. superwoman1-cleistogamy, a hopeful allele for gene containment in GM rice.
- Author
-
Yoshida, Hitoshi, Itoh, Jun‐Ichi, Ohmori, Shinnosuke, Miyoshi, Kazumaru, Horigome, Ayako, Uchida, Eiji, Kimizu, Mayumi, Matsumura, Yoko, Kusaba, Makoto, Satoh, Hikaru, and Nagato, Yasuo
- Subjects
- *
BOTANY , *CLEISTOGAMY , *PLANT fertilization , *POLLINATION , *TRANSGENIC rice , *RICE , *CROPS , *PLANT self-incompatibility , *HETEROSTYLISM - Abstract
Cleistogamy is an efficient strategy for preventing gene flow from genetically modified (GM) crops. We identified a cleistogamous mutant of rice harbouring a missense mutation (the 45th residue isoleucine to threonine; I45T) in the class-B MADS-box gene SUPERWOMAN1 ( SPW1), which specifies the identities of lodicules (equivalent to petals) and stamens. In the mutant, spw1-cls, the stamens are normal, but the lodicules are transformed homeotically to lodicule–glume mosaic organs, thereby engendering cleistogamy. Since this mutation does not affect other agronomic traits, it can be used in crosses to produce transgenic lines that do not cause environmental perturbation. Molecular analysis revealed that the reduced heterodimerization ability of SPW1I45T with its counterpart class-B proteins OsMADS2 and OsMADS4 caused altered lodicule identity. spw1-cls is the first useful mutant for practical gene containment in GM rice. Cleistogamy is possible in many cereals by engineering class-B floral homeotic genes and thereby inducing lodicule identity changes. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
6. The small interfering RNA production pathway is required for shoot meristem initiation in rice.
- Author
-
Nagasaki, Hiroshi, Itoh, Jun-ichi, Hayashi, Katsunobu, Hibara, Ken-ichiro, Satoh-Nagasawa, Namiko, Nosaka, Misuzu, Mukouhata, Motohiro, Ashikari, Motoyuki, Kitanos, Hidemi, Matsuoka, Makoto, Nagato, Yasuo, and Sato, Yutaka
- Subjects
- *
SHOOT apical meristems , *PLANT shoots , *MERISTEMS , *PLANT cells & tissues , *PLANT mutation , *RICE , *PLANT genetics - Abstract
The shoot apical meristem (SAM) is a group of stem cells that are responsible for plant development. Mutations in rice SHOOTLESS2 (SHL2), SHL4/SHOOT ORGANIZATION2 (SHO2), and SHO1 cause complete deletion or abnormal formation of the SAM. In this study we showed that defects in SAM formation in shl mutants are associated with the loss of expression of the homeodomain-leucine zipper (HD-ZIPIII) family genes. Rice SHL2, SHL4/SHO2, and SHO1 encoded orthologues of Arabidopsis RNA-dependent RNA polymerase 6, ARGONAUTE (AGO) 7, and DICER-like 4, respectively, whose mutations affect leaf development through the trans-acting siRNA (ta·siRNA) pathway. This suggested that the ta-siRNA pathway regulates the critical step of SAM formation during rice embryogenesis. The gain-of-function experiment by the ectopic expression of SHL4 resulted in reduced accumulation of an microRNA. miR166, and partial adaxialization of leaves, supporting a role for the ta-siRNA pathway in the maintenance of leaf polarity as previously reported in maize. Analysis of the spatiotemporal expression patterns of HD-ZIPIII and miR166 in wild-type and sh mutant embryos suggested that the loss of HD-ZIPIII expression in the SAM region of the developing embryo is the result of ectopic expression of miR166. Our analysis of shl mutants demonstrated that HD-ZIPIII expression regulated by miR166 is sensitive to the ta-siRNA pathway during SAM formation in rice embryogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
7. Rice Plant Development: from Zygote to Spikelet.
- Author
-
Itoh, Jun-Ichi, Nonomura, Ken-Ichi, Ikeda, Kyoko, Yamaki, Shinichiro, Inukai, Yoshiaki, Yamagishi, Hiroshi, Kitano, Hidemi, and Nagato, Yasuo
- Subjects
- *
MONOCOTYLEDONS , *ZYGOTES , *PLANT genetics , *PLANT growth , *PLANT development - Abstract
Rice is becoming a model plant in monocotyledons and a model cereal crop. For better understanding of the rice plant, it is essential to elucidate the developmental programs of the life cycle. To date, several attempts have been made in rice to categorize the developmental processes of some organs into substages. These studies are based exclusively on the morphological and anatomical viewpoints. Recent advancement in genetics and molecular biology has given us new aspects of developmental processes. In this review, we first describe the phasic development of the rice plant, and then describe in detail the developmental courses of major organs, leaf, root and spikelet, and specific organs/tissues. Also, for the facility of future studies, we propose a staging system for each organ. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
8. PLASTOCHRON3/GOLIATH encodes a glutamate carboxypeptidase required for proper development in rice.
- Author
-
Kawakatsu, Taiji, Taramino, Graziana, Itoh, Jun-Ichi, Allen, Justin, Sato, Yutaka, Soon-Kwan Hong, Yule, Ryan, Nagasawa, Nobuhiro, Kojima, Mikiko, Kusaba, Makoto, Sakakibara, Hitoshi, Sakai, Hajime, and Nagato, Yasuo
- Subjects
- *
SHOOT apical meristems , *RICE , *GLUTAMIC acid , *CARBOXYPEPTIDASES , *PHENOTYPES - Abstract
Most aerial parts of the plant body are products of the continuous activity of the shoot apical meristem (SAM). Leaves are the major component of the aerial plant body, and their temporal and spatial distribution mainly determines shoot architecture. Here we report the identification of the rice gene PLASTOCHRON3 ( PLA3)/ GOLIATH ( GO) that regulates various developmental processes including the rate of leaf initiation (the plastochron). PLA3/ GO encodes a glutamate carboxypeptidase, which is thought to catabolize small acidic peptides and produce small signaling molecules. pla3 exhibits similar phenotypes to pla1 and pla2– a shortened plastochron, precocious leaf maturation and rachis branch-to-shoot conversion in the reproductive phase. However, in contrast to pla1 and pla2, pla3 showed pleiotropic phenotypes including enlarged embryo, seed vivipary, defects in SAM maintenance and aberrant leaf morphology. Consistent with these pleiotropic phenotypes, PLA3 is expressed in the whole plant body, and is involved in plant hormone homeostasis. Double mutant analysis revealed that PLA1, PLA2 and PLA3 are regulated independently but function redundantly. Our results suggest that PLA3 modulates various signaling pathways associated with a number of developmental processes. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
9. Genome-wide analysis of spatiotemporal expression patterns during rice leaf development.
- Author
-
Miya, Masayuki, Yoshikawa, Takanori, Sato, Yutaka, and Itoh, Jun-Ichi
- Subjects
- *
LEAF development , *RICE , *GERMPLASM , *TISSUE differentiation , *IN situ hybridization , *GENES - Abstract
Background: Rice leaves consist of three distinct regions along a proximal-distal axis, namely the leaf blade, sheath, and blade-sheath boundary region. Each region has a unique morphology and function, but the genetic programs underlying the development of each region are poorly understood. To fully elucidate rice leaf development and discover genes with unique functions in rice and grasses, it is crucial to explore genome-wide transcriptional profiles during the development of the three regions. Results: In this study, we performed microarray analysis to profile the spatial and temporal patterns of gene expression in the rice leaf using dissected parts of leaves sampled in broad developmental stages. The dynamics in each region revealed that the transcriptomes changed dramatically throughout the progress of tissue differentiation, and those of the leaf blade and sheath differed greatly at the mature stage. Cluster analysis of expression patterns among leaf parts revealed groups of genes that may be involved in specific biological processes related to rice leaf development. Moreover, we found novel genes potentially involved in rice leaf development using a combination of transcriptome data and in situ hybridization, and analyzed their spatial expression patterns at high resolution. We successfully identified multiple genes that exhibit localized expression in tissues characteristic of rice or grass leaves. Conclusions: Although the genetic mechanisms of leaf development have been elucidated in several eudicots, direct application of that information to rice and grasses is not appropriate due to the morphological and developmental differences between them. Our analysis provides not only insights into the development of rice leaves but also expression profiles that serve as a valuable resource for gene discovery. The genes and gene clusters identified in this study may facilitate future research on the unique developmental mechanisms of rice leaves. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. LEAF LATERAL SYMMETRY1, a Member of the WUSCHEL-RELATED HOMEOBOX3 Gene Family, Regulates Lateral Organ Development Differentially from Other Paralogs, NARROW LEAF2 and NARROW LEAF3 in Rice.
- Author
-
Honda, Eriko, Yew, Chow-Lih, Yoshikawa, Takanori, Sato, Yutaka, Hibara, Ken-ichiro, and Itoh, Jun-Ichi
- Subjects
- *
LEAF development , *HOMEOBOX genes of plants , *GENE expression in plants , *GENETIC overexpression ,RICE genetics - Abstract
In several eudicot species, one copy of each member of the WUSCHEL-RELATED HOMEOBOX (WOX) gene family, WOX1 and WOX3, is redundantly or differentially involved in lateral leaf outgrowth, whereas only the WOX3 gene regulating the lateral domain of leaf development has been reported in grass. In this study, we show that a WOX3 gene, LEAF LATERAL SYMMETRY1 (LSY1), regulates lateral leaf development in a different manner ftom that of other duplicated paralogs of WOX3, NARROW LEAF2 (NAL2)/NAL3, in rice. A loss-of-function mutant of LSY1 exhibited an asymmetrical defect from early leaf development, which is different from a symmetric defect in a double loss-of-function mutant of NAL2/3, whereas the expression of both genes was observed in a similar domain in the margins of leaf primordia. Unlike NAL2/3, overexpression of LSY1 produced malformed leaves whose margins were curled adaxially. Expression domains and the level of adaxial/abaxial marker genes were affected in the LSY1-overexpressing plants, indicating that LSY1 is involved in regulation of adaxial-abaxial patterning at the margins of the leaf primordia. Additive phenotypes in some leaf traits of lsy1 nal2/3 triple mutants and the unchanged level of NAL2/3 expression in the lsy1 background suggested that LSY1 regulates lateral leaf development independently of NAL2/3. Our results indicated that all of the rice WOX3 genes are involved in leaf lateral outgrowth, but the functions of LSY1 and NAL2/3 have diverged. We propose that the function of WOX3 and the regulatory mode of leaf development in rice are comparable with those of WOX1/WOX3 in eudicot species. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
11. The rice FISH BONE gene encodes a tryptophan aminotransferase, which affects pleiotropic auxin-related processes.
- Author
-
Yoshikawa, Takanori, Ito, Momoyo, Sumikura, Tsuyoshi, Nakayama, Akira, Nishimura, Takeshi, Kitano, Hidemi, Yamaguchi, Isomaro, Koshiba, Tomokazu, Hibara, Ken‐Ichiro, Nagato, Yasuo, and Itoh, Jun‐Ichi
- Subjects
- *
TRYPTOPHAN , *AMINOTRANSFERASES , *AUXIN , *FISH anatomy , *GENETIC mutation ,RICE genetics - Abstract
Auxin is a fundamental plant hormone and its localization within organs plays pivotal roles in plant growth and development. Analysis of many Arabidopsis mutants that were defective in auxin biosynthesis revealed that the indole-3-pyruvic acid ( IPA) pathway, catalyzed by the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS ( TAA) and YUCCA ( YUC) families, is the major biosynthetic pathway of indole-3-acetic acid ( IAA). In contrast, little information is known about the molecular mechanisms of auxin biosynthesis in rice. In this study, we identified a auxin-related rice mutant, fish bone ( fib). FIB encodes an orthologue of TAA genes and loss of FIB function resulted in pleiotropic abnormal phenotypes, such as small leaves with large lamina joint angles, abnormal vascular development, small panicles, abnormal organ identity and defects in root development, together with a reduction in internal IAA levels. Moreover, we found that auxin sensitivity and polar transport activity were altered in the fib mutant. From these results, we suggest that FIB plays a pivotal role in IAA biosynthesis in rice and that auxin biosynthesis, transport and sensitivity are closely interrelated. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
12. Organ fusion and defective shoot development in oni3 mutants of rice.
- Author
-
Akiba, Takafumi, Hibara, Ken-Ichiro, Kimura, Fumiko, Tsuda, Katsutoshi, Shibata, Kiko, Ishibashi, Mayu, Moriya, Chihiro, Nakagawa, Kiyotaka, Kurata, Nori, Itoh, Jun-Ichi, and Ito, Yukihiro
- Subjects
- *
PLANT shoots , *PLANT development , *GENETIC mutation , *RICE , *GENE expression , *GERMINATION , *ARABIDOPSIS - Abstract
Maintenance of organ separation is one of the essential phenomena for normal plant development. We have identified and analyzed ONION3 (ONI3), which is required for avoiding organ fusions in rice. Loss-of-function mutations of ONI3, which were identified as mutants with ectopic expression of KNOX genes in leaves and morphologically resembling KNOX overexpressors, showed abnormal organ fusions in developing shoots. The mutant seedlings showed fusions between neighboring organs and also within an organ; they stopped growing soon after germination and subsequently died. ONI3 was shown to encode an enzyme that is most similar to Arabidopsis HOTHEAD and is involved in biosynthesis of long-chain fatty acids. Expression analyses showed that ONI3 was specifically expressed in the outermost cell layer in the shoot apex throughout life cycle, and the oni3 mutants had an aberrant outermost cell layer. Our results together with previous studies suggest that long-chain fatty acids are required for avoiding organ fusions and promoting normal shoot development in rice. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
13. ABERRANT PANICLE ORGANIZATION 2/RFL, the rice ortholog of Arabidopsis LEAFY, suppresses the transition from inflorescence meristem to floral meristem through interaction with APO1.
- Author
-
Ikeda-Kawakatsu, Kyoko, Maekawa, Masahiko, Izawa, Takeshi, Itoh, Jun-Ichi, and Nagato, Yasuo
- Subjects
- *
RICE , *ARABIDOPSIS , *MERISTEMS , *PLANT development , *MOLECULAR cloning , *MONOCOTYLEDONS , *GENETIC regulation in plants - Abstract
Summary The temporal and spatial control of meristem identity is a key element in plant development. To better understand the molecular mechanisms that regulate inflorescence and flower architecture, we characterized the rice aberrant panicle organization 2 ( apo2) mutant which exhibits small panicles with reduced number of primary branches due to the precocious formation of spikelet meristems. The apo2 mutants also display a shortened plastochron in the vegetative phase, late flowering, aberrant floral organ identities and loss of floral meristem determinacy. Map-based cloning revealed that APO2 is identical to previously reported RFL gene, the rice ortholog of the Arabidopsis LEAFY ( LFY) gene. Further analysis indicated that APO2/RFL and APO1, the rice ortholog of Arabidopsis UNUSUAL FLORAL ORGANS, act cooperatively to control inflorescence and flower development. The present study revealed functional differences between APO2/RFL and LFY. In particular, APO2/RFL and LFY act oppositely on inflorescence development. Therefore, the genetic mechanisms for controlling inflorescence architecture have evolutionarily diverged between rice (monocots) and Arabidopsis (eudicots). [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
14. COP1 Ortholog PPS Regulates the Juvenile–Adult and Vegetative–Reproductive Phase Changes in Rice.
- Author
-
Tanaka, Nobuhiro, Itoh, Hironori, Sentoku, Naoki, Kojima, Mikiko, Sakakibara, Hitoshi, Izawa, Takeshi, Itoh, Jun-Ichi, and Nagato, Yasuo
- Subjects
- *
PLANT life cycles , *ARABIDOPSIS , *RICE , *FLOWERING time , *ARABIDOPSIS thaliana , *PLANT development - Abstract
Because plant reproductive development occurs only in adult plants, the juvenile-to-adult phase change is an indispensable part of the plant life cycle. We identified two allelic mutants, peter pan syndrome-1 (pps-1) and pps-2 , that prolong the juvenile phase in rice (Oryza sativa) and showed that rice PPS is an ortholog of Arabidopsis thaliana CONSTITUTIVE PHOTOMORPHOGENIC1. The pps-1 mutant exhibits delayed expression of miR156 and miR172 and the suppression of GA biosynthetic genes, reducing the GA3 content in this mutant. In spite of its prolonged juvenile phase, the pps-1 mutant flowers early, and this is associated with derepression of RAP1B expression in pps-1 plants independently of the Hd1 - Hd3a/RFT1 photoperiodic pathway. PPS is strongly expressed in the fourth and fifth leaves, suggesting that it regulates the onset of the adult phase downstream of MORI1 and upstream of miR156 and miR172. Its ability to regulate the vegetative phase change and the time of flowering suggests that rice PPS acquired novel functions during the evolution of rice/monocots. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
15. Rice OPEN BEAK is a negative regulator of class 1 knox genes and a positive regulator of class B floral homeotic gene.
- Author
-
Horigome, Ayako, Nagasawa, Nobuhiro, Ikeda, Kyoko, Ito, Momoyo, Itoh, Jun-Ichi, and Nagato, Yasuo
- Subjects
- *
PLANT development , *RICE , *HOMEOBOX genes , *MORPHOGENESIS , *CELL proliferation , *STAMEN - Abstract
Numerous genes are involved in the regulation of plant development, including those that regulate floral homeotic genes, We identified two recessive allelic rice mutants, open beak-1 ( opb-1) and opb-2, which exhibited pleiotropic defects in leaf morphogenesis, inflorescence architecture, and floral organ identity. Abnormal cell proliferation was observed in the leaves and spikelets, and ectopic or overexpression of several class 1 knox genes was detected; thus, the abnormal cell proliferation in opb mutants is probably caused by ectopic class 1 knox gene expression. The opb mutants also had defects in floral organ identity, resulting in the development of mosaic organs, including gluminous lodicules, staminoid lodicules, and pistiloid stamens. These results, together with the reduced expression of a class B gene, indicate that OPB positively regulates the expression of class B genes. Map-based cloning revealed that OPB encodes a transcription factor that is orthologous to the Arabidopsis JAGGED gene and is expressed in leaf primordia, inflorescence meristem, rachis branch meristems, floral meristem, and floral organ primordia. Taken together, our data suggest that the OPB gene affects cellular proliferation and floral organ identity through the regulation of class 1 knox genes and floral homeotic genes. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
16. The rice FLATTENED SHOOT MERISTEM, encoding CAF-1 p150 subunit, is required for meristem maintenance by regulating the cell-cycle period
- Author
-
Abe, Masashi, Kuroshita, Hideaki, Umeda, Masaaki, Itoh, Jun-Ichi, and Nagato, Yasuo
- Subjects
- *
MERISTEMS , *PLANT cells & tissues , *PLANT growth , *PHENOTYPES - Abstract
Abstract: We isolated flattened shoot meristem (fsm) mutants in rice that showed defective seedling growth and died in the vegetative phase. Since most fsm plants had flat and small shoot apical meristems (SAMs), we suggest that FSM is required for proper SAM maintenance. FSM encodes a putative ortholog of Arabidopsis FASCIATA1 (FAS1) that corresponds to the p150 subunit of chromatin assembly factor-1 (CAF-1). FSM is expressed patchily in tissues with actively dividing cells, suggesting a tight association of FSM with specific cell-cycle phases. Double-target in situ hybridization counterstained with cell-cycle marker genes revealed that FSM is expressed mainly in the G1 phase. In fsm, expressions of the two marker genes representing S- and G2- to M-phases were enhanced in SAM, despite a reduced number of cells in SAM, suggesting that S- and G2-phases are prolonged in fsm. In addition, developmental events in fsm leaves took place at the proper time, indicating that the temporal regulation of development occurs independently of the cell-cycle period. In contrast to the fasciated phenotype of Arabidopsis fas1, fsm showed size reduction of SAM. The opposite phenotypes between fsm and fas1 indicate that the SAM maintenance is regulated differently between rice and Arabidopsis. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
17. PLASTOCHRON1, a timekeeper of leaf initiation in rice, encodes cytochrome P450.
- Author
-
Miyoshi, Kazumaru, Ahn, Syung-Ohg, Kawakatsu, Taiji, Ito, Yukihiro, Itoh, Jun-Ichi, Nagato, Yasuo, and Kurata, Non
- Subjects
- *
LEAVES , *PLANT growth , *CYTOCHROME P-450 , *MONOOXYGENASES , *RICE , *MERISTEMS - Abstract
During postembryonic development of higher plants, the shoot apical meristem produces lateral organs in a regular spacing (phyllotaxy) and a regular timing (plastochron). Molecular analysis of mutants associated with phyllotaxy and plastochron would greatly increase understanding of the developmental mechanism of plant architecture because phyllotaxy and plastochron are fundamental regulators of plant architecture. pla 1 of rice is not only a plastochron mutant showing rapid leaf initiation without affecting phyllotaxy, but also a heterochronic mutant showing ectopic shoot formation in the reproductive phase. Thus, pla1 provides a tool for analyzing the molecular basis of temporal regulation in leaf development. In this work, we isolated the PLA1 gene by map-based cloning. The identified PLA1 gene encodes a cytochrome P450, CYP78A11, which potentially catalyzes substances controlling plant development. PLA1 is expressed in developing leaf primordia, bracts of the panicle, and elongating internodes, but not in the shoot apical meristem. The expression pattern and mutant phenotype suggest that the PLA1 gene acting in developing leaf primordia affects the timing of successive leaf initiation and the termination of vegetative growth. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.