101
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Golan G, Betzer R, Wolf S. Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development. FRONTIERS IN PLANT SCIENCE 2013; 4:329. [PMID: 23986770 PMCID: PMC3750518 DOI: 10.3389/fpls.2013.00329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/04/2013] [Indexed: 05/05/2023]
Abstract
Phloem sap contains a large repertoire of macromolecules in addition to sugars, amino acids, growth substances and ions. The transcription profile of melon phloem sap contains over 1000 mRNA molecules, most of them associated with signal transduction, transcriptional control, and stress and defense responses. Heterografting experiments have established the long-distance trafficking of numerous mRNA molecules. Interestingly, several trafficking transcripts are involved in the auxin response, including two molecules coding for auxin/indole acetic acid (Aux/IAA). To further explore the biological role of the melon Aux/IAA transcript CmF-308 in the vascular tissue, a cassette containing the coding sequence of this gene under a phloem-specific promoter was introduced into tomato plants. The number of lateral roots was significantly higher in transgenic plants expressing CmF-308 under the AtSUC2 promoter than in controls. A similar effect on root development was obtained after transient expression of CmF-308 in source leaves of N. benthamiana plants. An auxin-response assay showed that CmF-308-transgenic roots are more sensitive to auxin than control roots. In addition to the altered root development, phloem-specific expression of CmF-308 resulted in shorter plants, a higher number of lateral shoots and delayed flowering, a phenotype resembling reduced apical dominance. In contrast to the root response, cotyledons of the transgenic plants were less sensitive to auxin than control cotyledons. The reduced auxin sensitivity in the shoot tissue was confirmed by lower relative expression of several Aux/IAA genes in leaves and an increase in the relative expression of a cytokinin-response regulator, TRR8/9b. The accumulated data suggest that expression of Aux/IAA in the phloem modifies auxin sensitivity in a tissue-specific manner, thereby altering plant development.
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Affiliation(s)
| | | | - Shmuel Wolf
- *Correspondence: Shmuel Wolf, The Robert H. Smith Faculty of Agriculture, Food and Environment, Otto Warburg Minerva Center for Agricultural Biotechnology, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 761001, Israel e-mail:
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102
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Abstract
Compound tomato leaves are composed of multiple leaflets that are generated gradually during leaf development, and each resembles a simple leaf. The elaboration of a compound leaf form requires the maintenance of transient organogenic activity at the leaf margin. The developmental window of organogenic activity is defined by the antagonistic activities of factors that promote maturation, such as TCP transcription factors, SFT and gibberellin, and factors that delay maturation, such as KNOX transcription factors and cytokinin. Leaflet initiation sites are specified spatially and temporally by spaced and specific activities of CUCs, auxin and ENTIRE, as well as additional factors. The partially indeterminate growth of the compound tomato leaf makes it a useful model to understand the balance between determinate and indeterminate growth, and the mechanisms of organogenesis, some of which are common to many developmental processes in plants.
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Affiliation(s)
- Yogev Burko
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot, Israel
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103
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Marsch-Martínez N, Ramos-Cruz D, Irepan Reyes-Olalde J, Lozano-Sotomayor P, Zúñiga-Mayo VM, de Folter S. The role of cytokinin during Arabidopsis gynoecia and fruit morphogenesis and patterning. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:222-34. [PMID: 22640521 DOI: 10.1111/j.1365-313x.2012.05062.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cytokinins have many essential roles in embryonic and post-embryonic growth and development, but their role in fruit morphogenesis is currently not really known. Moreover, information about the spatio-temporal localization pattern of cytokinin signaling in gynoecia and fruits is lacking. Therefore, the synthetic reporter line TCS::GFP was used to visualize cytokinin signaling during gynoecium and fruit development. Fluorescence was detected at medial regions of developing gynoecia, and, unexpectedly, at the valve margin in developing fruits, and was severely altered in mutants that lack or ectopically acquire valve margin identity. Comparison to developing gynoecia and fruits in a DR5rev::GFP line showed that the transcriptional responses to cytokinin and auxin are frequently present in complementary patterns. Moreover, cytokinin treatments in early gynoecia produced conspicuous changes, and treatment of valve margin mutant fruits restored this tissue. The results suggest that the phytohormone cytokinin is important in gynoecium and fruit patterning and morphogenesis, playing at least two roles: an early proliferation-inducing role at the medial tissues of the developing gynoecia, and a late role in fruit patterning and morphogenesis at the valve margin of developing fruits.
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Affiliation(s)
- Nayelli Marsch-Martínez
- Departamento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, km 9.6 Libramiento Norte, Carretera Irapuato-León, Irapuato, Guanajuato, Mexico.
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104
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Ben-Gera H, Ori N. Auxin and LANCEOLATE affect leaf shape in tomato via different developmental processes. PLANT SIGNALING & BEHAVIOR 2012; 7:1255-7. [PMID: 22902691 PMCID: PMC3493407 DOI: 10.4161/psb.21550] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Elaboration of a complex leaves depends on the morphogenetic activity of a specific tissue at the leaf margin termed marginal-blastozon (MB). In tomato (Solanum lycopersicym), prolonged activity of the MB leads to the development of compound leaves. The activity of the MB is restricted by the TCP transcription factor LANCEOLATE (LA). Plants harboring the dominant LA mutant allele La-2 have simple leaves with a uniform blade. Conversely, leaves of pFIL > > miR319 are compound and grow indeterminately in their margins due to leaf overexpression of miR319, a negative regulator of LA and additional miR319-sensitive genes. We have recently shown that the auxin-response sensor DR5::VENUS marks and precedes leaflet initiation events in the MB. Mutations in ENTIRE (E), an auxin signal inhibitor from the Aux/IAA family, lead to the expansion of the DR5::VENUS signal to throughout the leaf-primordia margin, and to a simplified leaf phenotype. Here, we examined the interaction between auxin, E, and LA in tomato leaf development. In La-2 leaf primordia, the auxin signal is very weak and is diffused to throughout the leaf margin, suggesting that auxin acts within the developmental-context of MB activity, which is controlled by LA. e La-2 double mutants showed an enhanced simple leaf phenotype and e pFIL > > miR319 leaves initiated less leaflets than wild-type, but their margins showed continuous growth. These results suggest that E and auxin affect leaflet initiation within the context of the extended MB activity, but their influence on the extent of indeterminate growth of the leaf is minor.
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105
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Matsuo S, Kikuchi K, Fukuda M, Honda I, Imanishi S. Roles and regulation of cytokinins in tomato fruit development. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5569-79. [PMID: 22865911 PMCID: PMC3444270 DOI: 10.1093/jxb/ers207] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cytokinins (CKs) are thought to play important roles in fruit development, especially cell division. However, the mechanisms and regulation of CK activity have not been well investigated. This study analysed CK concentrations and expression of genes involved in CK metabolism in developing tomato (Solanum lycopersicum) ovaries. The concentrations of CK ribosides and isopentenyladenine and the transcript levels of the CK biosynthetic genes SlIPT3, SlIPT4, SlLOG6, and SlLOG8 were high at anthesis and decreased immediately afterward. In contrast, trans-zeatin concentration and the transcript levels of the CK biosynthetic genes SlIPT1, SlIPT2, SlCYP735A1, SlCYP735A2, and SlLOG2 increased after anthesis. The expression of type-A response regulator genes was high in tomato ovaries from pre-anthesis to early post-anthesis stages. These results suggest that the CK signal transduction pathway is active in the cell division phase of fruit development. This study also investigated the effect of CK application on fruit set and development. Application of a synthetic CK, N-(2-chloro-pyridin-4-yl)-N'-phenylurea (CPPU), to unpollinated tomato ovaries induced parthenocarpic fruit development. The CPPU-induced parthenocarpic fruits were smaller than pollinated fruits, because of reduction of pericarp cell size rather than reduced cell number. Thus, CPPU-induced parthenocarpy was attributable to the promotion of cell division, not cell expansion. Overall, the results provide evidence that CKs are involved in cell division during development of tomato fruit.
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Affiliation(s)
- Satoshi Matsuo
- NARO Institute of Vegetable and Tea Science, National Agriculture and Food Research Organization (NARO), 360 Kusawa, Ano, Tsu, Mie 514-2392 Japan.
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106
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Nakayama N, Smith R, Mandel T, Robinson S, Kimura S, Boudaoud A, Kuhlemeier C. Mechanical Regulation of Auxin-Mediated Growth. Curr Biol 2012; 22:1468-76. [DOI: 10.1016/j.cub.2012.06.050] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/26/2012] [Accepted: 06/19/2012] [Indexed: 11/29/2022]
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107
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Box MS, Dodsworth S, Rudall PJ, Bateman RM, Glover BJ. Flower-specific KNOX phenotype in the orchid Dactylorhiza fuchsii. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:4811-9. [PMID: 22771852 PMCID: PMC3428008 DOI: 10.1093/jxb/ers152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The KNOTTED1-like homeobox (KNOX) genes are best known for maintaining a pluripotent stem-cell population in the shoot apical meristem that underlies indeterminate vegetative growth, allowing plants to adapt their development to suit the prevailing environmental conditions. More recently, the function of the KNOX gene family has been expanded to include additional roles in lateral organ development such as complex leaf morphogenesis, which has come to dominate the KNOX literature. Despite several reports implicating KNOX genes in the development of carpels and floral elaborations such as petal spurs, few authors have investigated the role of KNOX genes in flower development. Evidence is presented here of a flower-specific KNOX function in the development of the elaborate flowers of the orchid Dactylorhiza fuchsii, which have a three-lobed labellum petal with a prominent spur. Using degenerate PCR, four Class I KNOX genes (DfKN1-4) have been isolated, one from each of the four major Class I KNOX subclades and by reverse transcription PCR (RT-PCR), it is demonstrated that DfKNOX transcripts are detectable in developing floral organs such as the spur-bearing labellum and inferior ovary. Although constitutive expression of the DfKN2 transcript in tobacco produces a wide range of floral abnormalities, including serrated petal margins, extra petal tissue, and fused organs, none of the vegetative phenotypes typical of constitutive KNOX expression were produced. These data are highly suggestive of a role for KNOX expression in floral development that may be especially important in taxa with elaborate flowers.
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Affiliation(s)
- Mathew S. Box
- Department of Plant Sciences, University of CambridgeDowning Street, Cambridge CB2 3EA, UK
| | - Steven Dodsworth
- Department of Plant Sciences, University of CambridgeDowning Street, Cambridge CB2 3EA, UK
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic GardensKew, Richmond, Surrey TW9 3AB, UK
| | - Richard M. Bateman
- Jodrell Laboratory, Royal Botanic GardensKew, Richmond, Surrey TW9 3AB, UK
| | - Beverley J. Glover
- Department of Plant Sciences, University of CambridgeDowning Street, Cambridge CB2 3EA, UK
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108
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Steiner E, Yanai O, Efroni I, Ori N, Eshed Y, Weiss D. Class I TCPs modulate cytokinin-induced branching and meristematic activity in tomato. PLANT SIGNALING & BEHAVIOR 2012; 7:807-10. [PMID: 22751297 PMCID: PMC3583969 DOI: 10.4161/psb.20606] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Arabidopsis TCPs are a family of basic helix loop helix (bHLH)-type transcription factors. Previous studies suggested that antagonistic activities of class I TCPs and class II TCPs are correlated with cell proliferation. We have recently shown that the class I TCPs AtTCP14 and AtTCP15 promote typical cytokinin (CK) responses in Arabidopsis, and proposed that they mediate the effect of CK on cell divisions. To further study the role of AtTCP14 and AtTCP15 in plant development, we expressed them in tomato plants. AtTCP14 and AtTCP15-expressing tomato plants were semi-dwarf, had a reduced apical dominance and developed ectopic meristems on leaflet petioles. CK application to tomato seedlings promoted axillary bud outgrowth and this effect was enhanced in the transgenic AtTCP14 and AtTCP15 overexpressing plants. The results of this study extend our previous suggestion that AtTCP14 and AtTCP15 modulate the plant sensitivity to CK.
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Affiliation(s)
- Evyatar Steiner
- Institute of Plant Sciences and Genetics in Agriculture; The Robert H. Smith Faculty of Agriculture; Department of Food and Environment; The Hebrew University of Jerusalem; Rehovot, Israel
| | - Osnat Yanai
- Institute of Plant Sciences and Genetics in Agriculture; The Robert H. Smith Faculty of Agriculture; Department of Food and Environment; The Hebrew University of Jerusalem; Rehovot, Israel
| | - Idan Efroni
- Department of Biology; Center for Genomics and Systems Biology; New York University; New York, NY USA
| | - Naomi Ori
- Institute of Plant Sciences and Genetics in Agriculture; The Robert H. Smith Faculty of Agriculture; Department of Food and Environment; The Hebrew University of Jerusalem; Rehovot, Israel
| | - Yuval Eshed
- Department of Plant Sciences; The Weizmann Institute of Science; Rehovot, Israel
| | - David Weiss
- Institute of Plant Sciences and Genetics in Agriculture; The Robert H. Smith Faculty of Agriculture; Department of Food and Environment; The Hebrew University of Jerusalem; Rehovot, Israel
- Correspondence to: David Weiss,
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109
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Chitwood DH, Headland LR, Ranjan A, Martinez CC, Braybrook SA, Koenig DP, Kuhlemeier C, Smith RS, Sinha NR. Leaf asymmetry as a developmental constraint imposed by auxin-dependent phyllotactic patterning. THE PLANT CELL 2012; 24:2318-27. [PMID: 22722959 PMCID: PMC3406905 DOI: 10.1105/tpc.112.098798] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In a majority of species, leaf development is thought to proceed in a bilaterally symmetric fashion without systematic asymmetries. This is despite the left and right sides of an initiating primordium occupying niches that differ in their distance from sinks and sources of auxin. Here, we revisit an existing model of auxin transport sufficient to recreate spiral phyllotactic patterns and find previously overlooked asymmetries between auxin distribution and the centers of leaf primordia. We show that it is the direction of the phyllotactic spiral that determines the side of the leaf these asymmetries fall on. We empirically confirm the presence of an asymmetric auxin response using a DR5 reporter and observe morphological asymmetries in young leaf primordia. Notably, these morphological asymmetries persist in mature leaves, and we observe left-right asymmetries in the superficially bilaterally symmetric leaves of tomato (Solanum lycopersicum) and Arabidopsis thaliana that are consistent with modeled predictions. We further demonstrate that auxin application to a single side of a leaf primordium is sufficient to recapitulate the asymmetries we observe. Our results provide a framework to study a previously overlooked developmental axis and provide insights into the developmental constraints imposed upon leaf morphology by auxin-dependent phyllotactic patterning.
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Affiliation(s)
- Daniel H. Chitwood
- Department of Plant Biology, University of California, Davis, California 95616
| | - Lauren R. Headland
- Department of Plant Biology, University of California, Davis, California 95616
| | - Aashish Ranjan
- Department of Plant Biology, University of California, Davis, California 95616
| | - Ciera C. Martinez
- Department of Plant Biology, University of California, Davis, California 95616
| | | | - Daniel P. Koenig
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany
| | - Cris Kuhlemeier
- Institute of Plant Sciences, University of Bern, CH-3013 Bern, Switzerland
| | - Richard S. Smith
- Institute of Plant Sciences, University of Bern, CH-3013 Bern, Switzerland
| | - Neelima R. Sinha
- Department of Plant Biology, University of California, Davis, California 95616
- Address correspondence to
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110
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Ben-Gera H, Shwartz I, Shao MR, Shani E, Estelle M, Ori N. ENTIRE and GOBLET promote leaflet development in tomato by modulating auxin response. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:903-15. [PMID: 22332729 DOI: 10.1111/j.1365-313x.2012.04939.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Compound leaves produce leaflets in a highly controlled yet flexible pattern. Here, we investigate the interaction between auxin, the putative auxin response inhibitor ENTIRE (E, SlIAA9) and the CUC transcription factor GOBLET (GOB) in compound-leaf development in tomato (Solanum lycopersicum). Auxin maxima, monitored by the auxin response sensor DR5, marked and preceded leaflet and lobe initiation. The DR5 signal increased, but maxima were partially retained in response to the external or internal elevation of auxin levels. E directly interacted with the auxin receptors SlTIR1 and SlAFB6. Furthermore, E was stabilized by a mutation in domain II of the protein and by the inhibition of auxin or proteasome activity, implying that E is subjected to auxin-mediated degradation. In e mutants the DR5 signal expanded to include the complete leaf margin, and leaf-specific overexpression of a stabilized form of E inhibited the DR5 signal and lamina expansion. Genetic manipulation of GOB activity altered the distribution of the DR5 signal, and the inhibition of auxin transport or activity suppressed the GOB overexpression phenotype, suggesting that auxin mediates GOB-regulated leaf patterning. Whereas leaves of single e or gob mutants developed only primary leaflets, the downregulation of both E and GOB resulted in the complete abolishment of leaflet initiation, and in a strong DR5 signal throughout the leaf margin. These results suggest that E and GOB modulate auxin response and leaflet morphogenesis via partly redundant pathways, and that proper leaflet initiation and separation requires distinct boundaries between regions of lamina growth and adjacent regions in which growth is inhibited.
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Affiliation(s)
- Hadas Ben-Gera
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture and The Otto Warburg Minerva Center for Agricultural Biotechnology, Hebrew University, P.O. Box 12, Rehovot 76100, Israel
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111
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Gupta S, Rashotte AM. Down-stream components of cytokinin signaling and the role of cytokinin throughout the plant. PLANT CELL REPORTS 2012; 31:801-12. [PMID: 22315145 DOI: 10.1007/s00299-012-1233-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 05/09/2023]
Abstract
Cytokinins constitute a class of plant hormones influencing numerous aspects of growth and development. These processes occur through the downstream components of the cytokinin signaling pathway after its perception and signal transduction. The importance of these downstream signaling components has been revealed through the use of both traditional genetic and advanced molecular approaches studying mutants and transgenic lines involving cytokinin and diverse plant growth and developmental processes. Interestingly, these effects are not always directly via cytokinin, but by interactions with other plants hormones or transcription factor cascades, which can involve regulatory loops that affect transcription as well as hormone concentrations. This review covers recent advancements in understanding the role of cytokinin via its signaling components, specifically the downstream responses regulators in controlling vital plant growth and developmental processes.
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Affiliation(s)
- Sarika Gupta
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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112
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Kierzkowski D, Nakayama N, Routier-Kierzkowska AL, Weber A, Bayer E, Schorderet M, Reinhardt D, Kuhlemeier C, Smith RS. Elastic Domains Regulate Growth and Organogenesis in the Plant Shoot Apical Meristem. Science 2012; 335:1096-9. [PMID: 22383847 DOI: 10.1126/science.1213100] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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113
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Durbak A, Yao H, McSteen P. Hormone signaling in plant development. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:92-6. [PMID: 22244082 DOI: 10.1016/j.pbi.2011.12.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 12/23/2011] [Accepted: 12/23/2011] [Indexed: 05/20/2023]
Abstract
Hormone signaling plays diverse and critical roles during plant development. In particular, hormone interactions regulate meristem function and therefore control formation of all organs in the plant. Recent advances have dissected commonalities and differences in the interaction of auxin and cytokinin in the regulation of shoot and root apical meristem function. In addition, brassinosteroid hormones have recently been discovered to regulate root apical meristem size. Further insights have also been made into our understanding of the mechanism of crosstalk among auxin, cytokinin, and strigolactone in axillary meristems.
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Affiliation(s)
- Amanda Durbak
- Division of Biological Sciences, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, United States
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114
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Steiner E, Efroni I, Gopalraj M, Saathoff K, Tseng TS, Kieffer M, Eshed Y, Olszewski N, Weiss D. The Arabidopsis O-linked N-acetylglucosamine transferase SPINDLY interacts with class I TCPs to facilitate cytokinin responses in leaves and flowers. THE PLANT CELL 2012; 24:96-108. [PMID: 22267487 PMCID: PMC3289577 DOI: 10.1105/tpc.111.093518] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 12/21/2011] [Accepted: 01/05/2012] [Indexed: 05/18/2023]
Abstract
O-linked N-acetylglucosamine (O-GlcNAc) modifications regulate the posttranslational fate of target proteins. The Arabidopsis thaliana O-GlcNAc transferase (OGT) SPINDLY (SPY) suppresses gibberellin signaling and promotes cytokinin (CK) responses by unknown mechanisms. Here, we present evidence that two closely related class I TCP transcription factors, TCP14 and TCP15, act with SPY to promote CK responses. TCP14 and TCP15 interacted with SPY in yeast two-hybrid and in vitro pull-down assays and were O-GlcNAc modified in Escherichia coli by the Arabidopsis OGT, SECRET AGENT. Overexpression of TCP14 severely affected plant development in a SPY-dependent manner and stimulated typical CK morphological responses, as well as the expression of the CK-regulated gene RESPONSE REGULATOR5. TCP14 also promoted the transcriptional activity of the CK-induced mitotic factor CYCLIN B1;2. Whereas TCP14-overexpressing plants were hypersensitive to CK, spy and tcp14 tcp15 double mutant leaves and flowers were hyposensitive to the hormone. Reducing CK levels by overexpressing CK OXIDASE/DEHYDROGENASE3 suppressed the TCP14 overexpression phenotypes, and this suppression was reversed when the plants were treated with exogenous CK. Taken together, we suggest that responses of leaves and flowers to CK are mediated by SPY-dependent TCP14 and TCP15 activities.
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Affiliation(s)
- Evyatar Steiner
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Idan Efroni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Manjula Gopalraj
- Department of Plant Biology and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Katie Saathoff
- Department of Plant Biology and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Tong-Seung Tseng
- Department of Plant Biology and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Martin Kieffer
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Yuval Eshed
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Neil Olszewski
- Department of Plant Biology and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - David Weiss
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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115
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Nakayama H, Nakayama N, Nakamasu A, Sinha N, Kimura S. Toward elucidating the mechanisms that regulate heterophylly. ACTA ACUST UNITED AC 2012. [DOI: 10.5685/plmorphol.24.57] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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116
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Yanai O, Shani E, Russ D, Ori N. Gibberellin partly mediates LANCEOLATE activity in tomato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:571-82. [PMID: 21771122 DOI: 10.1111/j.1365-313x.2011.04716.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Elaboration of a compound leaf shape depends on extended morphogenetic activity in developing leaves. In tomato (Solanum lycopersicum), the CIN-TCP transcription factor LANCEOLATE (LA) promotes leaf differentiation. LA is negatively regulated by miR319 during the early stages of leaf development, and decreased sensitivity of LA mRNA to miR319 recognition in the semi-dominant mutant La leads to prematurely increased LA expression, precocious leaf differentiation and a simpler and smaller leaf. Increased levels or responses of the plant hormone gibberellin (GA) in tomato leaves also led to a simplified leaf form. Here, we show that LA activity is mediated in part by GA. Expression of the SlGA20 oxidase1 (SlGA20ox1) gene, which encodes an enzyme in the GA biosynthesis pathway, is increased in gain-of-function La mutants and reduced in plants that over-express miR319. Conversely, the transcript levels of the GA deactivation gene SlGA2 oxidase4 (SlGA2ox4) are increased in plants over-expressing miR319. The miR319 over-expression phenotype is suppressed by exogenous GA application and by a mutation in the PROCERA (PRO) gene, which encodes an inhibitor of the GA response. SlGA2ox4 is expressed in initiating leaflets during early leaf development. Its expression expands as a result of miR319 over-expression, and its over-expression leads to increased leaf complexity. These results suggest that LA activity is partly mediated by positive regulation of the GA response, probably by regulation of GA levels.
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Affiliation(s)
- Osnat Yanai
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture and the Otto Warburg Minerva Center for Agricultural Biotechnology, Hebrew University, Rehovot 76100, Israel
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117
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Box MS, Dodsworth S, Rudall PJ, Bateman RM, Glover BJ. Characterization of Linaria KNOX genes suggests a role in petal-spur development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:703-14. [PMID: 21790812 DOI: 10.1111/j.1365-313x.2011.04721.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Spurs are tubular outgrowths of perianth organs that have evolved iteratively among angiosperms. They typically contain nectar and often strongly influence pollinator specificity, potentially mediating reproductive isolation. The identification of Antirrhinum majus mutants with ectopic petal spurs suggested that petal-spur development is dependent on the expression of KNOTTED 1-like homeobox (KNOX) genes, which are better known for their role in maintaining the shoot apical meristem. Here, we tested the role of KNOX genes in petal-spur development by isolating orthologs of the A. majus KNOX genes Hirzina (AmHirz) and Invaginata (AmIna) from Linaria vulgaris, a related species that differs from A. majus in possessing long, narrow petal spurs. We name these genes LvHirz and LvIna, respectively. Using quantitative reverse-transcription PCR, we show that LvHirz is expressed at high levels in the developing petals and demonstrate that the expression of petal-associated KNOX genes is sufficient to induce sac-like outgrowths on petals in a heterologous host. We propose a model in which KNOX gene expression during early petal-spur development promotes and maintains further morphogenetic potential of the petal, as previously described for KNOX gene function in compound leaf development. These data indicate that petal spurs could have evolved by changes in regulatory gene expression that cause rapid and potentially saltational phenotypic modifications. Given the morphological similarity of spur ontogeny in distantly related taxa, changes in KNOX gene expression patterns could be a shared feature of spur development in angiosperms.
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Affiliation(s)
- Mathew S Box
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
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Peng J, Yu J, Wang H, Guo Y, Li G, Bai G, Chen R. Regulation of compound leaf development in Medicago truncatula by fused compound leaf1, a class M KNOX gene. THE PLANT CELL 2011; 23:3929-43. [PMID: 22080596 PMCID: PMC3246329 DOI: 10.1105/tpc.111.089128] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/07/2011] [Accepted: 10/31/2011] [Indexed: 05/22/2023]
Abstract
Medicago truncatula is a legume species belonging to the inverted repeat lacking clade (IRLC) with trifoliolate compound leaves. However, the regulatory mechanisms underlying development of trifoliolate leaves in legumes remain largely unknown. Here, we report isolation and characterization of fused compound leaf1 (fcl1) mutants of M. truncatula. Phenotypic analysis suggests that FCL1 plays a positive role in boundary separation and proximal-distal axis development of compound leaves. Map-based cloning indicates that FCL1 encodes a class M KNOX protein that harbors the MEINOX domain but lacks the homeodomain. Yeast two-hybrid assays show that FCL1 interacts with a subset of Arabidopsis thaliana BEL1-like proteins with slightly different substrate specificities from the Arabidopsis homolog KNATM-B. Double mutant analyses with M. truncatula single leaflet1 (sgl1) and palmate-like pentafoliata1 (palm1) leaf mutants show that fcl1 is epistatic to palm1 and sgl1 is epistatic to fcl1 in terms of leaf complexity and that SGL1 and FCL1 act additively and are required for petiole development. Previous studies have shown that the canonical KNOX proteins are not involved in compound leaf development in IRLC legumes. The identification of FCL1 supports the role of a truncated KNOX protein in compound leaf development in M. truncatula.
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Affiliation(s)
- Jianling Peng
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Jianbin Yu
- U.S. Department of Agriculture/Agricultural Research Service, Hard Winter Wheat Genetics Research Unit, Manhattan, Kansas 66506
- Department of Agronomy, Kansas State University, Manhattan, Kansas 66506
| | - Hongliang Wang
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Yingqing Guo
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Guangming Li
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Guihua Bai
- U.S. Department of Agriculture/Agricultural Research Service, Hard Winter Wheat Genetics Research Unit, Manhattan, Kansas 66506
- Department of Agronomy, Kansas State University, Manhattan, Kansas 66506
| | - Rujin Chen
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
- Address correspondence to
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Busch BL, Schmitz G, Rossmann S, Piron F, Ding J, Bendahmane A, Theres K. Shoot branching and leaf dissection in tomato are regulated by homologous gene modules. THE PLANT CELL 2011; 23:3595-609. [PMID: 22039213 PMCID: PMC3229137 DOI: 10.1105/tpc.111.087981] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 09/19/2011] [Accepted: 10/17/2011] [Indexed: 05/18/2023]
Abstract
Aerial plant architecture is predominantly determined by shoot branching and leaf morphology, which are governed by apparently unrelated developmental processes, axillary meristem formation, and leaf dissection. Here, we show that in tomato (Solanum lycopersicum), these processes share essential functions in boundary establishment. Potato leaf (C), a key regulator of leaf dissection, was identified to be the closest paralog of the shoot branching regulator Blind (Bl). Comparative genomics revealed that these two R2R3 MYB genes are orthologs of the Arabidopsis thaliana branching regulator REGULATOR OF AXILLARY MERISTEMS1 (RAX1). Expression studies and complementation analyses indicate that these genes have undergone sub- or neofunctionalization due to promoter differentiation. C acts in a pathway independent of other identified leaf dissection regulators. Furthermore, the known leaf complexity regulator Goblet (Gob) is crucial for axillary meristem initiation and acts in parallel to C and Bl. Finally, RNA in situ hybridization revealed that the branching regulator Lateral suppressor (Ls) is also expressed in leaves. All four boundary genes, C, Bl, Gob, and Ls, may act by suppressing growth, as indicated by gain-of-function plants. Thus, leaf architecture and shoot architecture rely on a conserved mechanism of boundary formation preceding the initiation of leaflets and axillary meristems.
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Affiliation(s)
- Bernhard L. Busch
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Gregor Schmitz
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Susanne Rossmann
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Florence Piron
- Unité de Recherche en Génomique Végétale, Unité Mixte de Recherche, Institut National de la Recherche Agronomique–Centre National de la Recherche Scientifique, 91057 Evry cedex, France
| | - Jia Ding
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Abdelhafid Bendahmane
- Unité de Recherche en Génomique Végétale, Unité Mixte de Recherche, Institut National de la Recherche Agronomique–Centre National de la Recherche Scientifique, 91057 Evry cedex, France
| | - Klaus Theres
- Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
- Address correspondence to
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Yoshida S, Mandel T, Kuhlemeier C. Stem cell activation by light guides plant organogenesis. Genes Dev 2011; 25:1439-50. [PMID: 21724835 DOI: 10.1101/gad.631211] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Leaves originate from stem cells located at the shoot apical meristem. The meristem is shielded from the environment by older leaves, and leaf initiation is considered to be an autonomous process that does not depend on environmental cues. Here we show that light acts as a morphogenic signal that controls leaf initiation and stabilizes leaf positioning. Leaf initiation in tomato shoot apices ceases in the dark but resumes in the light, an effect that is mediated through the plant hormone cytokinin. Dark treatment also affects the subcellular localization of the auxin transporter PIN1 and the concomitant formation of auxin maxima. We propose that cytokinin is required for meristem propagation, and that auxin redirects cytokinin-inducible meristem growth toward organ formation. In contrast to common wisdom over the last 150 years, the light environment controls the initiation of lateral organs by regulating two key hormones: auxin and cytokinin.
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Affiliation(s)
- Saiko Yoshida
- Institute of Plant Sciences, University of Bern, CH-3013 Bern, Switzerland
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Fleishon S, Shani E, Ori N, Weiss D. Negative reciprocal interactions between gibberellin and cytokinin in tomato. THE NEW PHYTOLOGIST 2011; 190:609-17. [PMID: 21244434 DOI: 10.1111/j.1469-8137.2010.03616.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
• The hormones gibberellin (GA) and cytokinin (CK) exhibit antagonistic effects on various processes in many species. Previous studies in Arabidopsis have shown that GA inhibits CK signaling. Here, we have investigated the cross-talk between GA and CK in tomato (Solanum lycopersicum). • We altered the balance between GA and CK activities by exogenous applications and genetic manipulations, and tested an array of physiological and developmental responses. • GA and CK showed antagonistic effects on various developmental and molecular processes during tomato plant growth. GA inhibited all tested CK responses, including the induction of the CK primary response genes, type A Tomato Response Regulators (TRRs). CK also inhibited a subset of GA responses. In contrast with exogenous application of GA, the endogenous GA-independent GA signal generated by the loss of the DELLA gene PROCERA (PRO) did not repress CK-regulated processes, such as anthocyanin accumulation, TRR expression and leaf complexity. • Our results suggest a mutual antagonistic interaction between GA and CK in tomato. Although GA may inhibit early steps in the CK response pathway via a DELLA-independent pathway, CK appears to affect downstream branch(es) of the GA signaling pathway. The ratio between the two hormones, rather than their absolute levels, determines the final response.
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Affiliation(s)
- Shay Fleishon
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Srinivasan C, Liu Z, Scorza R. Ectopic expression of class 1 KNOX genes induce adventitious shoot regeneration and alter growth and development of tobacco (Nicotiana tabacum L) and European plum (Prunus domestica L). PLANT CELL REPORTS 2011; 30:655-64. [PMID: 21212958 DOI: 10.1007/s00299-010-0993-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 05/07/2023]
Abstract
Transgenic plants of tobacco (Nicotiana tabacum L) and European plum (Prunus domestica L) were produced by transforming with the apple class 1 KNOX genes (MdKN1 and MdKN2) or corn KNOX1 gene. Transgenic tobacco plants were regenerated in vitro from transformed leaf discs cultured in a medium lacking cytokinin. Ectopic expression of KNOX genes retarded shoot growth by suppressing elongation of internodes in transgenic tobacco plants. Expression of each of the three KNOX1 genes induced malformation and extensive lobbing in tobacco leaves. In situ regeneration of adventitious shoots was observed from leaves and roots of transgenic tobacco plants expressing each of the three KNOX genes. In vitro culture of leaf explants and internode sections excised from in vitro grown MdKN1 expressing tobacco shoots regenerated adventitious shoots on MS (Murashige and Skoog 1962) basal medium in the absence of exogenous cytokinin. Transgenic plum plants that expressed the MdKN2 or corn KNOX1 gene grew normally but MdKN1 caused a significant reduction in plant height, leaf shape and size and produced malformed curly leaves. A high frequency of adventitious shoot regeneration (96%) was observed in cultures of leaf explants excised from corn KNOX1-expressing transgenic plum shoots. In contrast to KNOX1-expressing tobacco, leaf and internode explants of corn KNOX1-expressing plum required synthetic cytokinin (thidiazuron) in the culture medium to induce adventitious shoot regeneration. The induction of high-frequency regeneration of adventitious shoots in vitro from leaves and stem internodal sections of plum through the ectopic expression of a KNOX1 gene is the first such report for a woody perennial fruit trees.
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Affiliation(s)
- C Srinivasan
- United States Department of Agriculture, Agricultural Research Service, Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV 25430, USA.
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Shleizer-Burko S, Burko Y, Ben-Herzel O, Ori N. Dynamic growth program regulated by LANCEOLATE enables flexible leaf patterning. Development 2011; 138:695-704. [PMID: 21228002 DOI: 10.1242/dev.056770] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
During their development, leaves progress through a highly controlled yet flexible developmental program. Transcription factors from the CIN-TCP family affect leaf shape by regulating the timing of leaf maturation. Characterization of mutants in the tomato (Solanum lycopersicum) CIN-TCP gene LANCEOLATE (LA) led us to hypothesize that a threshold LA-like activity promotes leaf differentiation. Here, we examined the relationship between LA activity, leaf maturation, and final leaf size and shape. Leaves of diverse shapes from various Solanaceae species or from different positions on the tomato plant differed in the timing of growth and maturation, and these were often associated with altered LA expression dynamics. Accordingly, genetic manipulations of LA activity in tomato altered leaf growth and maturation, leading to changes in leaf size and shape. LA expression sustained until late stages of tomato leaf development, and stage-specific overexpression of miR319, a negative regulator of CIN-TCP genes, confirmed that LA-like proteins affect leaf development through these late stages. Together, our results imply that dynamic spatial and temporal leaf maturation, coordinated by LA-like genes, enables the formation of variable leaf forms.
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Affiliation(s)
- Sharona Shleizer-Burko
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel
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