The Dominant Developmental Mutants of Tomato, Mouse-ear and Curl, Are Associated with Distinct Modes of Abnormal Transcriptional Regulation of a Knotted Gene

Parnis, Ania; Cohen, Orit; Gutfinger, Tamar; Hareven, Dana; Zamir, Daniel; Lifschitz, Eliezer

doi:10.2307/3870575

Cited by 34 publications

(54 citation statements)

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“…Among the best studied of these are the MADS-box family of genes that control floral-organ identity (Pnueli et al 1991(Pnueli et al , 1994a and the knotted1-like homeobox (KNOXI) genes that regulate leaf morphogenesis (Avivi et al 2000;Janssen et al 1998;Chen et al 1997;Parnis et al 1997;Hareven et al 1996). Moreover, a large number of loci affecting vegetative and floral morphology have been identified through mutant analysis (Stevens and Rick 1986).…”

Section: Correspondence Of Qtl To Known Mutant Loci In Tomatomentioning

confidence: 99%

A comparative study of the genetic bases of natural variation in tomato leaf, sepal, and petal morphology

2004

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In an effort to better understand the dramatic differences in vegetative and floral morphology that differentiate species within the genus Lycopersicon, quantitative trait loci (QTL) for leaflet and perianth size and shape characters were mapped in an interspecific F2 population of tomato (Lycopersicon esculentum x L. pennellii). Thirty-six highly significant (P < or = 0.001) QTL were associated with 18 separate traits. QTL for correlated traits were generally not colocalized in the genome unless there was a clear codependence between the traits (e.g., organ length and area). Little or no overlap in QTL positioning between different organs was observed, suggesting that the genes determining the size and shape of leaflets, sepals, and petals are organ specific. Thus, while leaves are considered the developmental and evolutionary precursors to floral organs, genes acting late in development to determine certain aspects of morphology (namely shape and size) must have specialized to exert control over individual organs. Five of the leaflet-trait QTL map to analogous regions in the genome of eggplant, and therefore it appears there has been some conservation in the genes controlling leaf morphology within the Solanaceae.

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Section: Correspondence Of Qtl To Known Mutant Loci In Tomatomentioning

confidence: 99%

A comparative study of the genetic bases of natural variation in tomato leaf, sepal, and petal morphology

2004

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“…However, KNOX1 expression is reestablished later in the developing primordia of compound leafed plants (12)(13)(14)(15). Additionally, overexpression of KNOX1 genes in transgenic tomato plants or spontaneous tomato mutants results in leaves with increased numbers of leaflets (13,14,16). Therefore, it has been concluded that KNOX1 genes are involved in compound leaf formation by establishing an indeterminate environment within developing primordia.…”

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confidence: 99%

Regulation of SHOOT MERISTEMLESS genes via an upstream-conserved noncoding sequence coordinates leaf development

Uchida

Townsley

Chung

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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The indeterminate shoot apical meristem of plants is characterized by the expression of the Class 1 KNOTTED1-LIKE HOMEOBOX (KNOX1) genes. KNOX1 genes have been implicated in the acquisition and/or maintenance of meristematic fate. One of the earliest indicators of a switch in fate from indeterminate meristem to determinate leaf primordium is the down-regulation of KNOX1 genes orthologous to SHOOT MERISTEMLESS (STM) in Arabidopsis (hereafter called STM genes) in the initiating primordia. In simple leafed plants, this down-regulation persists during leaf formation. In compound leafed plants, however, KNOX1 gene expression is reestablished later in the developing primordia, creating an indeterminate environment for leaflet formation. Despite this knowledge, most aspects of how STM gene expression is regulated remain largely unknown. Here, we identify two evolutionarily conserved noncoding sequences within the 5 upstream region of STM genes in both simple and compound leafed species across monocots and dicots. We show that one of these elements is involved in the regulation of the persistent repression and/or the reestablishment of STM expression in the developing leaves but is not involved in the initial down-regulation in the initiating primordia. We also show evidence that this regulation is developmentally significant for leaf formation in the pathway involving ASYMMETRIC LEAVES1/2 (AS1/2) gene expression; these genes are known to function in leaf development. Together, these findings reveal a regulatory point of leaf development mediated through a conserved, noncoding sequence in STM genes.evolution ͉ KNOX1 ͉ shoot apical meristem T he shoot apical meristem (SAM) of plants is an indeterminate structure and the source of stem cells from which all aerial organs are derived. Indeterminacy during development is regulated by a suite of genes that function in the SAM. The process of organ initiation begins when cells in the incipient organ primordium change identity from indeterminate to determinate. The indeterminate SAM is characterized by the expression of the Class 1 KNOTTED1-LIKE HOMEOBOX (KNOX1) genes. KNOX1 genes have been implicated in the acquisition and/or maintenance of meristematic fate (1, 2). One of the earliest indicators of a switch in fate from indeterminate meristem to determinate leaf primordium is the down-regulation of KNOX1 genes orthologous to SHOOT MERISTEMLESS (STM) in Arabidopsis (hereafter called STM genes) in the incipient primordia (1).The SAM can give rise to two different leaf forms, simple or compound (3), and KNOX1 genes are down-regulated in the incipient primordia in both compound and simple leafed species. In simple leafed plants, this down-regulation persists during leaf formation (4-7), and overexpression of these genes is sufficient to cause leaf lobing and ectopic meristem formation (8-11). However, KNOX1 expression is reestablished later in the developing primordia of compound leafed plants (12-15). Additionally, overexpression of KNOX1 genes in transgenic tomato plants or spo...

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“…Subsets of these genes are essential for meristem maintenance and lateral organ formation in all higher plants (Burglin 1997;Sharma and Fletcher 2002). Ectopic expression of KNOX genes in various plants causes drastic alteration in leaf and Xower morphogenesis in spontaneous mutants (Smith et al 1992;Chen et al 1997;Parnis et al 1997) and dwarWsm and loss of apical dominance in transgenic plants (Matsuoka et al 1993;Sinha et al 1993;Lincoln et al 1994;Chuck et al 1996;Chen et al 1997;Parnis et al 1997). Alterations in morphology caused by ectopic expression of KNOX genes were also accompanied by hormone level changes.…”

Section: Discussionmentioning

confidence: 95%

A branched-chain aminotransferase may regulate hormone levels by affecting KNOX genes in plants

Gao

Wang

Wei

et al. 2009

Planta

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Branched-chain amino acid transaminases (BCATs) play a crucial role in the metabolic pathway of leucine, isoleucine and valine by catalyzing the last step of synthesis and/or the initial step of degradation of these amino acids. In this study, we characterized a new BCAT from Nicotiana benthamiana (NbBCAT, GeneBank accession No. EU194916), the deduced amino acid sequence of which exhibits a very high percentage of identity to the homologous enzymes from Solanum tuberosum (StBCAT-2, 91.5%) and Arabidopsis thaliana (AtBCAT1-6, 56.4-68.6%). Complementation experiment using a Deltabat1/Deltabat2 double knockout yeast strain system demonstrated enzymatic activities for NbBCAT. Ectopically expressed NbBCAT::green fluorescence fusion protein was targeted predominantly to the chloroplasts in tobacco protoplasts. The highest levels of NbBCAT transcripts were found in open flowers as well as in young leaves. Virus-induced gene silencing of NbBCAT resulted in abnormal leaf development and loss of apical dominance. In NbBCAT-silenced plants, two KNOTTED1-type genes, NTH15 and NTH23, were upregulated. This was accompanied by various hormone changes, as a result of transcriptional regulation of gibberellin 20-oxidase (Ntc12) and adenosine phosphate isopentenyltransferase. The transcript levels of NbBCAT could also be repressed by hormone treatment. These results suggest that NbBCAT, an enzyme in the branched-chain amino acid metabolic pathway, may be involved in the regulation of endogenous hormones by its effect on KNOX genes.

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The Dominant Developmental Mutants of Tomato, Mouse-ear and Curl, Are Associated with Distinct Modes of Abnormal Transcriptional Regulation of a Knotted Gene

Cited by 34 publications

References 0 publications

A comparative study of the genetic bases of natural variation in tomato leaf, sepal, and petal morphology

A comparative study of the genetic bases of natural variation in tomato leaf, sepal, and petal morphology

Regulation of SHOOT MERISTEMLESS genes via an upstream-conserved noncoding sequence coordinates leaf development

A branched-chain aminotransferase may regulate hormone levels by affecting KNOX genes in plants

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