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Didier Reinhardt - One of the best experts on this subject based on the ideXlab platform.
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Deregulation of MADS-box transcription factor genes in a mutant defective in the WUSCHEL-LIKE HOMEOBOX gene EVERGREEN of Petunia Hybrida.
Plant signaling & behavior, 2018Co-Authors: Martine Schorderet, R. R. Duvvuru Muni, A. Fiebig, Didier ReinhardtAbstract:Angiosperm inflorescences develop in two fundamentally different ways. In monopodial plants, for example in Arabidopsis thaliana, the flowers are initiated as lateral appendages of a central indeterminate inflorescence meristem. In sympodial plants, flowers arise by terminal differentiation of the inflorescence meristem, while further inflorescence development proceeds from new sympodial meristems that are generated at the flank of the terminal flower. We have used the sympodial model species Petunia Hybrida to investigate inflorescence development. Here, we describe a mutant, bonsai (bns), which is defective in flower formation, inflorescence branching, and control of meristem size. Detailed microscopic analysis revealed that bns meristems retain vegetative charateristics including spiral phyllotaxis. Consistent with a block in flower formation, bns mutants exhibit a deregulated expression of various MADS-box genes. Molecular analysis revealed that the bns mutant carries a transposon insertion in the previously described EVERGREEN (EVG) gene, which belongs to the WUSCHEL-LIKE HOMEOBOX (WOX) transcription factor gene family. EVG falls in the WOX9 subfamily, which has diverse developmental functions in angiosperms. The comparison of WOX9 orthologues in five model species for flowering shows that these genes play functionally divergent roles in monopodial and sympodial plants, indicating that the WOX9 regulatory node may have played an important role in the evolution of shoot architecture.
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role of the gras transcription factor ata ram1 in the transcriptional reprogramming of arbuscular mycorrhiza in Petunia Hybrida
BMC Genomics, 2017Co-Authors: Melanie K. Rich, Pierre-emmanuel Courty, Christophe Roux, Didier ReinhardtAbstract:Development of arbuscular mycorrhiza (AM) requires a fundamental reprogramming of root cells for symbiosis. This involves the induction of hundreds of genes in the host. A recently identified GRAS-type transcription factor in Petunia Hybrida, ATA/RAM1, is required for the induction of host genes during AM, and for morphogenesis of the fungal endosymbiont. To better understand the role of RAM1 in symbiosis, we set out to identify all genes that depend on activation by RAM1 in mycorrhizal roots. We have carried out a transcript profiling experiment by RNAseq of mycorrhizal plants vs. non-mycorrhizal controls in wild type and ram1 mutants. The results show that the expression of early genes required for AM, such as the strigolactone biosynthetic genes and the common symbiosis signalling genes, is independent of RAM1. In contrast, genes that are involved at later stages of symbiosis, for example for nutrient exchange in cortex cells, require RAM1 for induction. RAM1 itself is highly induced in mycorrhizal roots together with many other transcription factors, in particular GRAS proteins. Since RAM1 has previously been shown to be directly activated by the common symbiosis signalling pathway through CYCLOPS, we conclude that it acts as an early transcriptional switch that induces many AM-related genes, among them genes that are essential for the development of arbuscules, such as STR, STR2, RAM2, and PT4, besides hundreds of additional RAM1-dependent genes the role of which in symbiosis remains to be explored. Taken together, these results indicate that the defect in the morphogenesis of the fungal arbuscules in ram1 mutants may be an indirect consequence of functional defects in the host, which interfere with nutrient exchange and possibly other functions on which the fungus depends.
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Role of the GRAS transcription factor ATA/RAM1 in the transcriptional reprogramming of arbuscular mycorrhiza in Petunia Hybrida
BMC Genomics, 2017Co-Authors: Melanie K. Rich, Pierre-emmanuel Courty, Christophe Roux, Didier ReinhardtAbstract:Development of arbuscular mycorrhiza (AM) requires a fundamental reprogramming of root cells for symbiosis. This involves the induction of hundreds of genes in the host. A recently identified GRAS-type transcription factor in Petunia Hybrida, ATA/RAM1, is required for the induction of host genes during AM, and for morphogenesis of the fungal endosymbiont. To better understand the role of RAM1 in symbiosis, we set out to identify all genes that depend on activation by RAM1 in mycorrhizal roots. Results: We have carried out a transcript profiling experiment by RNAseq of mycorrhizal plants vs. non-mycorrhizal controls in wild type and ram1 mutants. The results show that the expression of early genes required for AM, such as the strigolactone biosynthetic genes and the common symbiosis signalling genes, is independent of RAM1. In contrast, genes that are involved at later stages of symbiosis, for example for nutrient exchange in cortex cells, require RAM1 for induction. RAM1 itself is highly induced in mycorrhizal roots together with many other transcription factors, in particular GRAS proteins. Conclusion : Since RAM1 has previously been shown to be directly activated by the common symbiosis signalling pathway through CYCLOPS, we conclude that it acts as an early transcriptional switch that induces many AM-related genes, among them genes that are essential for the development of arbuscules, such as STR, STR2, RAM2, and PT4, besides hundreds of additional RAM1-dependent genes the role of which in symbiosis remains to be explored. Taken together, these results indicate that the defect in the morphogenesis of the fungal arbuscules in ram1 mutants may be an indirect consequence of functional defects in the host, which interfere with nutrient exchange and possibly other functions on which the fungus depends.
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comprehensive transcriptome analysis unravels the existence of crucial genes regulating primary metabolism during adventitious root formation in Petunia Hybrida
PLOS ONE, 2014Co-Authors: Amir H Ahkami, Didier Reinhardt, Eva Nouri, Klaust Haensch, Uwe Druege, Uwe Scholz, Burkhard Steuernagel, Marc Strickert, Nicolaus Von Wiren, Philipp FrankenAbstract:To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia Hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1-specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase.
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phosphorus and nitrogen regulate arbuscular mycorrhizal symbiosis in Petunia Hybrida
PLOS ONE, 2014Co-Authors: Eva Nouri, Florence Breuillinsessoms, Urs Feller, Didier ReinhardtAbstract:Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia Hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia Hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi.
Kimberley C Snowden - One of the best experts on this subject based on the ideXlab platform.
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Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE7 Is Involved in the Production of Negative and Positive Branching Signals in Petunia
Plant physiology, 2009Co-Authors: Revel S. M. Drummond, Joanne L Simons, Bart J Janssen, Sakuntala Karunairetnam, N. Marcela Martinez-sanchez, Kerry Robert Templeton, Brian D. Quinn, Kimberley C SnowdenAbstract:One of the key factors that defines plant form is the regulation of when and where branches develop. The diversity of form observed in nature results, in part, from variation in the regulation of branching between species. Two CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes, CCD7 and CCD8, are required for the production of a branch-suppressing plant hormone. Here, we report that the decreased apical dominance3 (dad3) mutant of Petunia (Petunia Hybrida) results from the mutation of the PhCCD7 gene and has a less severe branching phenotype than mutation of PhCCD8 (dad1). An analysis of the expression of this gene in wild-type, mutant, and grafted Petunia suggests that in Petunia, CCD7 and CCD8 are coordinately regulated. In contrast to observations in Arabidopsis (Arabidopsis thaliana), ccd7ccd8 double mutants in Petunia show an additive phenotype. An analysis using dad3 or dad1 mutant scions grafted to wild-type rootstocks showed that when these plants produce adventitious mutant roots, branching is increased above that seen in plants where the mutant roots are removed. The results presented here indicate that mutation of either CCD7 or CCD8 in Petunia results in both the loss of an inhibitor of branching and an increase in a promoter of branching.
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the decreased apical dominance1 Petunia Hybrida carotenoid cleavage dioxygenase8 gene affects branch production and plays a role in leaf senescence root growth and flower development
The Plant Cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
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The Decreased apical dominance1/Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development
The Plant cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
David G. Clark - One of the best experts on this subject based on the ideXlab platform.
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phmyb4 fine tunes the floral volatile signature of Petunia Hybrida through phc4h
Journal of Experimental Botany, 2011Co-Authors: Thomas A Colquhoun, Jooyoung Kim, Ashlyn E Wedde, Laura A Levin, Kyle Schmitt, Robert C Schuurink, David G. ClarkAbstract:In Petunia×Hybrida cv ‘Mitchell Diploid’ (MD), floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis is controlled spatially, developmentally, and daily at molecular, metabolic, and biochemical levels. Multiple genes have been shown to encode proteins that either directly catalyse a biochemical reaction yielding FVBP compounds or are involved in metabolite flux prior to the formation of FVBP compounds. It was hypothesized that multiple transcription factors are involved in the precise regulation of all necessary genes, resulting in the specific volatile signature of MD flowers. After acquiring all available Petunia transcript sequences with homology to Arabidopsis thaliana R2R3-MYB transcription factors, PhMYB4 (named for its close identity to AtMYB4) was identified, cloned, and characterized. PhMYB4 transcripts accumulate to relatively high levels in floral tissues at anthesis and throughout open flower stages, which coincides with the spatial and developmental distribution of FVBP production and emission. Upon RNAi suppression of PhMYB4 (ir-PhMYB4) both Petunia CINNAMATE-4-HYDROXYLASE (PhC4H1 and PhC4H2) gene transcript levels were significantly increased. In addition, ir-PhMYB4 plants emit higher levels of FVBP compounds derived from p-coumaric acid (isoeugenol and eugenol) compared with MD. Together, these results indicate that PhMYB4 functions in the repression of C4H transcription, indirectly controlling the balance of FVBP production in Petunia floral tissue (i.e. fine-tunes).
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flower specific expression of the agrobacterium tumefaciens isopentenyltransferase gene results in radial expansion of floral organs in Petunia Hybrida
Plant Biotechnology Journal, 2008Co-Authors: Julian C Verdonk, Holly M. Loucas, Kenichi Shibuya, Thomas A Colquhoun, Beverly A Underwood, David G. ClarkAbstract:Abstract Biotechnology has the potential to modify commercially important traits of crops, such as fruit size and stress tolerance. To date, the floricultural industry has not profited significantly from these possibilities to manipulate, for example, flower size. Cytokinins are known to be involved in many aspects of plant development, including cell division. Increasing the amount of cytokinins has the potential to increase the size of an organ, such as the flower or the fruit. The Agrobacterium tumefaciens cytokinin biosynthesis gene isopentenyltransferase (ipt) has been shown to increase cytokinin levels when introduced into plants. Moreover, it has a dramatic effect on the vegetative development of plants. The expression of the ipt gene under the control of the flower-specific Arabidopsis APETALA3 promoter in Petunia (Petunia Hybrida) increases the flower size dramatically, but with no effect on vegetative development. The resulting transgenic plants produced flowers with larger corolla diameter and greater total floral fresh weight. This strategy has the potential for use in the production of ornamental crops with large flowers and crop species with larger fruit.
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the decreased apical dominance1 Petunia Hybrida carotenoid cleavage dioxygenase8 gene affects branch production and plays a role in leaf senescence root growth and flower development
The Plant Cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
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The Decreased apical dominance1/Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development
The Plant cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
Harry J. Klee - One of the best experts on this subject based on the ideXlab platform.
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the decreased apical dominance1 Petunia Hybrida carotenoid cleavage dioxygenase8 gene affects branch production and plays a role in leaf senescence root growth and flower development
The Plant Cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
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The Decreased apical dominance1/Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development
The Plant cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
Sakuntala Karunairetnam - One of the best experts on this subject based on the ideXlab platform.
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Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE7 Is Involved in the Production of Negative and Positive Branching Signals in Petunia
Plant physiology, 2009Co-Authors: Revel S. M. Drummond, Joanne L Simons, Bart J Janssen, Sakuntala Karunairetnam, N. Marcela Martinez-sanchez, Kerry Robert Templeton, Brian D. Quinn, Kimberley C SnowdenAbstract:One of the key factors that defines plant form is the regulation of when and where branches develop. The diversity of form observed in nature results, in part, from variation in the regulation of branching between species. Two CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes, CCD7 and CCD8, are required for the production of a branch-suppressing plant hormone. Here, we report that the decreased apical dominance3 (dad3) mutant of Petunia (Petunia Hybrida) results from the mutation of the PhCCD7 gene and has a less severe branching phenotype than mutation of PhCCD8 (dad1). An analysis of the expression of this gene in wild-type, mutant, and grafted Petunia suggests that in Petunia, CCD7 and CCD8 are coordinately regulated. In contrast to observations in Arabidopsis (Arabidopsis thaliana), ccd7ccd8 double mutants in Petunia show an additive phenotype. An analysis using dad3 or dad1 mutant scions grafted to wild-type rootstocks showed that when these plants produce adventitious mutant roots, branching is increased above that seen in plants where the mutant roots are removed. The results presented here indicate that mutation of either CCD7 or CCD8 in Petunia results in both the loss of an inhibitor of branching and an increase in a promoter of branching.
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the decreased apical dominance1 Petunia Hybrida carotenoid cleavage dioxygenase8 gene affects branch production and plays a role in leaf senescence root growth and flower development
The Plant Cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
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The Decreased apical dominance1/Petunia Hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development
The Plant cell, 2005Co-Authors: Kimberley C Snowden, Joanne L Simons, Bart J Janssen, Andrew J. Simkin, Kerry R. Templeton, Holly M. Loucas, Sakuntala Karunairetnam, Andrew P. Gleave, David G. Clark, Harry J. KleeAbstract:Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of Petunia (Petunia Hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.