ioan negrutiu - Academia.edu (original) (raw)

Papers by ioan negrutiu

Notulae Botanicae Horti Agrobotanici Cluj-napoca, May 28, 2013

Conservation agriculture is an alternative to conventional agriculture and one of the most effici... more Conservation agriculture is an alternative to conventional agriculture and one of the most efficient systems for sustainable agricultural development, stimulating soil biological activity, increasing organic matter and humus content. In order to evaluate the impact of the conservation agriculture system compared to the conventional agriculture system on wheat yield, a bi-factorial experiment on wheat crop based on split-plot model was organized in the Transylvania Plain, Romania, where there are a few research results in the field and the area has a high potential for the implementation of conservation agriculture system. First factor (' A') was agriculture system, having two levels: ' A1' tillage (classic) system and ' A2' no-tillage system, and the second, 'B' factor was fertilization, with three levels: 'B1' no fertilization, 'B2'-N 80 P 40 kg/ha, which is the average level practiced by farmers in the area and 'B3'-N 150 P 75 kg/ha, which is the recommended level for obtaining a high production performance specific to ' Ariesan' wheat cultivar used in this experiment. The results pointed out that, in comparison with conventional agriculture, the application of no-tillage system determined a lower wheat yield by 353 kg per surface unit. Fertilization assured a significant increase by 610 kg wheat grains per ha. In the case of the conservation agriculture system, the highest production gain was 1,260 kg/ha for 'B3A2' level compared to 'B1A2' level, where the highest fertilization level was applied. The lowest production gain was 410 kg/ha registered by 'B3A1-B1A1' which was the highest fertilizer dose in case of conventional agriculture. In conclusion, the application of no-tillage system increased the efficiency of fertilization in terms of wheat yield compared to the classical agriculture. As a result, it is recommended as farmers dealing with wheat cropping in the area and also in other regions with similar soil and climate conditions to implement conservation agriculture.

Le développement durable à découvert

Journal of Interdisciplinary Methodologies and Issues in Sciences, 2022

L’article aborde les enjeux liés au développement de l’observation et de l’évaluation environneme... more L’article aborde les enjeux liés au développement de l’observation et de l’évaluation environnementales, qui répondent pour partie à des politiques incitatives mais aussi à des prises de conscience tant institutionnelles que citoyennes. Notre contribution s’appuie sur l’expérimentation d’une approche systémique de comptabilité écologique (Comptabilité Écosystémique du Capital Naturel, CECN) à l’échelle du bassin versant du Rhône, en la confrontant à un modèle théorique, l’observatoire OSAGE. L’objectif, assorti de préconisations scientifiques, techniques et organisationnelles, fruits de cette confrontation, vise à s’interroger sur les capacités de déploiement de l’outil de CECN en un observatoire des ressources territoriales structuré par les dispositifs scientifique, technique et organisationnel d’OSAGE. La mise en œuvre efficace d’un tel outil appelle un besoin urgent de politiques publiques plus cohérentes en matière de données (temps, espaces, protocoles), enrichies par des plat...

L’anthropocene triomphant actuel, avec ses forcages environnementaux et sociaux, est a l’origine ... more L’anthropocene triomphant actuel, avec ses forcages environnementaux et sociaux, est a l’origine de l’acceleration des degradations des milieux de vie sur Terre et de l’accentuation des tensions sociales et geopolitiques. Passer a un anthropocene de gestion equitable, informe et sobre vis-a-vis de toutes les ressources et dans tous les secteurs d’activite (slow anthropocene), impose une analyse prealable sur l’ensemble des activites et des rapports humains. Cette transition dite « ecologique », mais en realite a la fois societale et ecologique, est tout sauf un ajustement technique de secteurs dits prioritaires et technocratiques. Elle est avant tout culturelle, politique et philosophique au sens propre du terme. Elle est un horizon pour des trajectoires de developpement humain, pour des constructions sociales et economiques, censees redefinir socialement richesse, bien-etre, travail etc. La denomination « transition ecologique » est largement vehiculee, mais ses bases conceptuelles...

The International journal of developmental biology, 1992

Protoplasts have usually been presented as a methodological tool. Even as such, they make possibl... more Protoplasts have usually been presented as a methodological tool. Even as such, they make possible an impressive array of applications in plant biology. Here we report on the use of protoplast-derived selectable markers in the study of several disturbed genetic systems with obvious effects on plant development: (1) auxotrophic mutants and the control of amino acid biosynthesis and transport in vegetative and reproductive tissues; (2) introgression of alien genetic information across phylogenetic boundaries by protoplast fusion, a consequence of controlled dedifferentiation-redifferentiation processes and attenuated incompatibility reactions in cultured cells; (3) expression (in)stability of foreign genes in transgenic plants during successive meiotic generations and in crosses between independent transformants.

Genetics, 1999

Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is u... more Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is under the control of two main regions on the Y chromosome. One such region, encoding the gynoecium-suppressing function (GSF), is responsible for the arrest of carpel initiation in male flowers. To generate chromosomal deletions, we used pollen irradiation in male plants to produce hermaphroditic mutants (bsx mutants) in which carpel development was restored. The mutants resulted from alterations in at least two GSF chromosomal regions, one autosomal and one located on the distal half of the (p)-arm of the Y chromosome. The two mutations affected carpel development independently, each mutation showing incomplete penetrance and variegation, albeit at significantly different levels. During successive meiotic generations, a progressive increase in penetrance and a reduction in variegation levels were observed and quantified at the level of the Y-linked GSF (GSF-Y). Possible mechanisms are pr...

Genetics, 1999

White campion is a dioecious plant with heteromorphic X and Y sex chromosomes. In male plants, a ... more White campion is a dioecious plant with heteromorphic X and Y sex chromosomes. In male plants, a filamentous structure replaces the pistil, while in female plants the stamens degenerate early in flower development. Asexual (asx) mutants, cumulating the two developmental defects that characterize the sexual dimorphism in this species, were produced by gamma ray irradiation of pollen and screening in the M1 generation. The mutants harbor a novel type of mutation affecting an early function in sporogenous/parietal cell differentiation within the anther. The function is called stamen-promoting function (SPF). The mutants are shown to result from interstitial deletions on the Y chromosome. We present evidence that such deletions tentatively cover the central domain on the (p)-arm of the Y chromosome (Y2 region). By comparing stamen development in wild-type female and asx mutant flowers we show that they share the same block in anther development, which results in the production of vestig...

FEBS Open Bio, 2018

The nucleoplasm and nucleolus are the two main territories of the nucleus. While specific functio... more The nucleoplasm and nucleolus are the two main territories of the nucleus. While specific functions are associated with each of these territories (such as mRNA synthesis in the nucleoplasm and ribosomal rRNA synthesis in the nucleolus), some proteins are known to be located in both. Here, we investigated the molecular function of REBELOTE (RBL), an Arabidopsis thaliana protein previously characterized as a regulator of floral meristem termination. We show that RBL displays a dual localization, in the nucleolus and nucleoplasm. Moreover, we used direct and global approaches to demonstrate that RBL interacts with nucleic acid-binding proteins. It binds to the NOC proteins SWA2, AtNOC2 and AtNOC3 in both the nucleolus and nucleoplasm, and also to OBE1 and VFP3/ENAP1. Taking into account the identities of these RBL interactors, we hypothesise that RBL acts both in ribosomal biogenesis and in the regulation of gene expression.

The Lancet Planetary Health, 2018

The EMBO Journal, 1987

Communicated by M.van Montagu We have isolated a 1.5-kb plant DNA fragment (called insert 7) from... more Communicated by M.van Montagu We have isolated a 1.5-kb plant DNA fragment (called insert 7) from Nicotiana plumbaginifolia DNA that contains a protoplast-specific enhancer-like sequence. The presence of this sequence on a plasmid carrying a chimeric nos-npt-H gene conferring kanamycin resistance to plant cells, produces an overexpression of the npt-H gene during at least eight days after protoplast transformation. This effect on the expression of the nos promoter was independent of the orientation and was observed both on circular and linearized plasmids. On the contrary, insert 7 had no influence when present on another plasmid (in trans) in cotransformation experiments. The overexpression of the nos-npt-l gene due to the presence of insert 7 on the transforming plasmid is correlated with a higher level of synthesis of the corresponding RNA. Insert 7 did not affect the level of expression of the nos-npt-H gene in stably transformed cafli, or in regenerated plants. However, the overexpression was again detected in protoplasts prepared from leaves of stably transformed plants. This 1.5-kb plant DNA fragment contains highly repetitive DNA sequences, specific to N. plumbaginifolia. However, the enhancer-like activity is localized on a 600-bp unique sequence of insert 7. Insert 7 had no detectable effect on the transient expression of another gene, the nopaline synthase gene present at a longer distance on the same plasmid.

Biotechnology & Biotechnological Equipment, 2005

Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolut... more Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolution. Current studies have been based on fluorescent in situ hybridization (FISH). FISH in situ hybridization in conjucation with Ag-staining was used to map physically the 18S.26S multigene rRNA family in S. latifolia L. The 18S-5.8S-26S rRNA genes have been located on four pairs of Silene chromosomes. The pairs of majors rRNA sites on chromosome 5, 7, 9 and 10 are well known. Silver staining of nuclei and in situ hybridization analysis have previously indicated that additional rDNA sites may be present, but the presence of sites on a five chromosome pairs was unexpected. Using FISH in situ hybridization, we report a new fifth locous in S. latifolia and also confirm the nucleolus organizing region (Nor) by Ag-staining. We propose calling the new sites Nor-11. In situ hybridization is valuable for gene mapping, since it can detect presence of genes with a very wide range of copy number at different sites.

Plant Science Letters, 1977

Arabidopsis thaliana is one of the best studied plant model organisms. Besides cultivation in gre... more Arabidopsis thaliana is one of the best studied plant model organisms. Besides cultivation in greenhouses, cells of this plant can also be propagated in suspension cell culture. At7 is one such cell line that was established about 25 years ago. Here, we report the sequencing and the analysis of the At7 genome. Large scale duplications and deletions compared to the Columbia-0 (Col-0) reference sequence were detected. The number of deletions exceeds the number of insertions, thus indicating that a haploid genome size reduction is ongoing. Patterns of small sequence variants differ from the ones observed between A. thaliana accessions, e.g., the number of single nucleotide variants matches the number of insertions/deletions. RNA-Seq analysis reveals that disrupted alleles are less frequent in the transcriptome than the native ones.

Annals of Botany, 2011

† Background and Aims Bisexual flowers of Carica papaya range from highly regular flowers to morp... more † Background and Aims Bisexual flowers of Carica papaya range from highly regular flowers to morphs with various fusions of stamens to the ovary. Arabidopsis thaliana sup1 mutants have carpels replaced by chimeric carpel-stamen structures. Comparative analysis of stamen to carpel conversions in the two different plant systems was used to understand the stage and origin of carpeloidy when derived from stamen tissues, and consequently to understand how carpeloidy contributes to innovations in flower evolution. † Methods Floral development of bisexual flowers of Carica was studied by scanning electron microscopy and was compared with teratological sup mutants of A. thaliana. † Key Results In Carica development of bisexual flowers was similar to wild (unisexual) forms up to locule initiation. Feminization ranges from fusion of stamen tissue to the gynoecium to complete carpeloidy of antepetalous stamens. In A. thaliana, partial stamen feminization occurs exclusively at the flower apex, with normal stamens forming at the periphery. Such transformations take place relatively late in development, indicating strong developmental plasticity of most stamen tissues. These results are compared with evo-devo theories on flower bisexuality, as derived from unisexual ancestors. The Arabidopsis data highlight possible early evolutionary events in the acquisition of bisexuality by a patchy transformation of stamen parts into female parts linked to a flower axis-position effect. The Carica results highlight tissue-fusion mechanisms in angiosperms leading to carpeloidy once bisexual flowers have evolved. † Conclusions We show two different developmental routes leading to stamen to carpel conversions by late re-specification. The process may be a fundamental aspect of flower development that is hidden in most instances by developmental homeostasis.

L Le es s R Re es ss so ou ur rc ce es s-l le e g gr ra an nd d e en nj je eu u d de e l la a t t... more L Le es s R Re es ss so ou ur rc ce es s-l le e g gr ra an nd d e en nj je eu u d de e l la a t tr ra an ns si it ti io on n s so oc ci ié ét ta al le e e et t é éc co ol lo og gi iq qu ue e  I I.. N Ne eg gr ru ut ti iu u Biologiste, Directeur de l'Institut Michel Serres, ENS de Lyon D D.. C Co ou uv ve et t Professeur au Muséum National d'Histoire Naturelles et à l'école polytechnique,

Theoretical and Applied Genetics, 1990

Communicated by Yu. Gleba we feel confident in speculating that intergenomic recombination betwee... more Communicated by Yu. Gleba we feel confident in speculating that intergenomic recombination between N. plumbaginifolia and N. tabacum has occurred.

Theoretical and Applied Genetics, 1990

Nicotiana plumbaginifolia mutant, "Nia26," were fused with v-irradiated mesophyll protoplasts of ... more Nicotiana plumbaginifolia mutant, "Nia26," were fused with v-irradiated mesophyll protoplasts of Nicotiana sylvestris, V-42. Hybrid selection was based on complementation of NR deficiency by transfer of the donor NR gene to N. plumbaginifolia. Regenerated hybrids had different numbers of donor chromosomes in a tetraploid background of N. plumbaginifolia. The transfer and expression of different isozymes from the donor were also observed. Six self-fertile regenerants were obtained from 21 independently isolated cell colonies. Progeny analyses revealed: (1) the linkage of NR and shikimate dehydrogenase (ShDh); (2) a stabilization of the transmission rate of NR; and (3) the obtainment of mono-and disomic addition lines in the first and second progeny of the original regenerants. Southern hybridization analyses demonstrated unequivocally the presence of the NR gene from the donor partner in progeny plants.

Theoretical and Applied Genetics, 1984

Two S-(2-aminoethyl)L-cysteine (AEC) resistant lines were isolated by screening mutagenized proto... more Two S-(2-aminoethyl)L-cysteine (AEC) resistant lines were isolated by screening mutagenized protoplasts from diploid N. sylvestris plants. Both lines accumulated free lysine at levels 10 to 20-fold higher than in controls. Lysine overproduction and AEC-resistance were also expressed in plants regenerated from the variant Cultures. A feedback insensitive form of dihydrodipicolinate synthase (DHPS), the pathway specific control enzyme for lysine synthesis, was detected in callus cultures and leaf extracts from the resistant lines. Aspartate kinase (AK), the other key enzyme in the regulation of lysine biosynthesis, was unaltered in the mutants. Crosses with wild type plants indicated that the mutation conferring insensitivity to feedback in DHPS, with as result overproduction of lysine and resistance to AEC, was inherited as a single dominant nuclear gene.

The Plant Journal, 2004

We report a comparative analysis of cell proliferation patterns during Arabidopsis¯ower developme... more We report a comparative analysis of cell proliferation patterns during Arabidopsis¯ower development. Cell division was evaluated by a direct method, i.e. the 5-bromo-2 H-deoxyuridine (BrdU) incorporation/immunodetection procedure. BrdU patterns in wild-type plants were correlated with the expression pro®les of both several cell cycle genes involved in the control of the G 1 /S transition and cell cycle-related repressor genes, MSI4 and MSI5, encoding WD-repeat proteins. To evaluate how proliferation patterns arise with respect to boundaries and vice versa, the expression of a boundary gene, CUP SHAPED COTYLEDON (CUC)2, was determined. Combining these approaches, we demonstrate that boundaries between in¯orescence and oral meristems and between¯oral whorls are narrow bands of non-dividing cells. In addition, we show that negative and positive regulators of cell proliferation are simultaneously and continuously expressed in dividing meristematic domains, being excluded from boundary cells. Finally, BrdU incorporation and CUC2 in situ hybridisation patterns were analysed in two mutant backgrounds, agamous (ag)-1 and superman (sup)-1, in order to assess changes in boundary establishment and different levels of indeterminacy under conditions of altered proliferation at the¯oral meristem centre.

The EMBO Journal, 1999

Unlike the majority of flowering plants, which possess hermaphrodite flowers, white campion (Sile... more Unlike the majority of flowering plants, which possess hermaphrodite flowers, white campion (Silene latifolia) is dioecious and has flowers of two different sexes. The sex is determined by the combination of heteromorphic sex chromosomes: XX in females and XY in males. The Y chromosome of S.latifolia was microdissected to generate a Y-specific probe which was used to screen a young male flower cDNA library. We identified five genes which represent the first active genes to be cloned from a plant Y chromosome. Here we report a detailed analysis of one of these genes, SlY1 (S.latifolia Y-gene 1). SlY1 is expressed predominantly in male flowers. A closely related gene, SlX1, is predicted to be located on the X chromosome and is strongly expressed in both male and female flowers. SlY1 and SlX1 encode almost identical proteins containing WD repeats. Immunolocalization experiments showed that these proteins are localized in the nucleus, and that they are most abundant in cells that are actively dividing or beginning to differentiate. Interestingly, they do not accumulate in arrested sexual organs and represent potential targets for sex determination genes. These genes will permit investigation of the origin and evolution of sex chromosomes in plants.

Notulae Botanicae Horti Agrobotanici Cluj-napoca, May 28, 2013

Conservation agriculture is an alternative to conventional agriculture and one of the most effici... more Conservation agriculture is an alternative to conventional agriculture and one of the most efficient systems for sustainable agricultural development, stimulating soil biological activity, increasing organic matter and humus content. In order to evaluate the impact of the conservation agriculture system compared to the conventional agriculture system on wheat yield, a bi-factorial experiment on wheat crop based on split-plot model was organized in the Transylvania Plain, Romania, where there are a few research results in the field and the area has a high potential for the implementation of conservation agriculture system. First factor (' A') was agriculture system, having two levels: ' A1' tillage (classic) system and ' A2' no-tillage system, and the second, 'B' factor was fertilization, with three levels: 'B1' no fertilization, 'B2'-N 80 P 40 kg/ha, which is the average level practiced by farmers in the area and 'B3'-N 150 P 75 kg/ha, which is the recommended level for obtaining a high production performance specific to ' Ariesan' wheat cultivar used in this experiment. The results pointed out that, in comparison with conventional agriculture, the application of no-tillage system determined a lower wheat yield by 353 kg per surface unit. Fertilization assured a significant increase by 610 kg wheat grains per ha. In the case of the conservation agriculture system, the highest production gain was 1,260 kg/ha for 'B3A2' level compared to 'B1A2' level, where the highest fertilization level was applied. The lowest production gain was 410 kg/ha registered by 'B3A1-B1A1' which was the highest fertilizer dose in case of conventional agriculture. In conclusion, the application of no-tillage system increased the efficiency of fertilization in terms of wheat yield compared to the classical agriculture. As a result, it is recommended as farmers dealing with wheat cropping in the area and also in other regions with similar soil and climate conditions to implement conservation agriculture.

Le développement durable à découvert

Journal of Interdisciplinary Methodologies and Issues in Sciences, 2022

L’article aborde les enjeux liés au développement de l’observation et de l’évaluation environneme... more L’article aborde les enjeux liés au développement de l’observation et de l’évaluation environnementales, qui répondent pour partie à des politiques incitatives mais aussi à des prises de conscience tant institutionnelles que citoyennes. Notre contribution s’appuie sur l’expérimentation d’une approche systémique de comptabilité écologique (Comptabilité Écosystémique du Capital Naturel, CECN) à l’échelle du bassin versant du Rhône, en la confrontant à un modèle théorique, l’observatoire OSAGE. L’objectif, assorti de préconisations scientifiques, techniques et organisationnelles, fruits de cette confrontation, vise à s’interroger sur les capacités de déploiement de l’outil de CECN en un observatoire des ressources territoriales structuré par les dispositifs scientifique, technique et organisationnel d’OSAGE. La mise en œuvre efficace d’un tel outil appelle un besoin urgent de politiques publiques plus cohérentes en matière de données (temps, espaces, protocoles), enrichies par des plat...

L’anthropocene triomphant actuel, avec ses forcages environnementaux et sociaux, est a l’origine ... more L’anthropocene triomphant actuel, avec ses forcages environnementaux et sociaux, est a l’origine de l’acceleration des degradations des milieux de vie sur Terre et de l’accentuation des tensions sociales et geopolitiques. Passer a un anthropocene de gestion equitable, informe et sobre vis-a-vis de toutes les ressources et dans tous les secteurs d’activite (slow anthropocene), impose une analyse prealable sur l’ensemble des activites et des rapports humains. Cette transition dite « ecologique », mais en realite a la fois societale et ecologique, est tout sauf un ajustement technique de secteurs dits prioritaires et technocratiques. Elle est avant tout culturelle, politique et philosophique au sens propre du terme. Elle est un horizon pour des trajectoires de developpement humain, pour des constructions sociales et economiques, censees redefinir socialement richesse, bien-etre, travail etc. La denomination « transition ecologique » est largement vehiculee, mais ses bases conceptuelles...

The International journal of developmental biology, 1992

Protoplasts have usually been presented as a methodological tool. Even as such, they make possibl... more Protoplasts have usually been presented as a methodological tool. Even as such, they make possible an impressive array of applications in plant biology. Here we report on the use of protoplast-derived selectable markers in the study of several disturbed genetic systems with obvious effects on plant development: (1) auxotrophic mutants and the control of amino acid biosynthesis and transport in vegetative and reproductive tissues; (2) introgression of alien genetic information across phylogenetic boundaries by protoplast fusion, a consequence of controlled dedifferentiation-redifferentiation processes and attenuated incompatibility reactions in cultured cells; (3) expression (in)stability of foreign genes in transgenic plants during successive meiotic generations and in crosses between independent transformants.

Genetics, 1999

Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is u... more Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is under the control of two main regions on the Y chromosome. One such region, encoding the gynoecium-suppressing function (GSF), is responsible for the arrest of carpel initiation in male flowers. To generate chromosomal deletions, we used pollen irradiation in male plants to produce hermaphroditic mutants (bsx mutants) in which carpel development was restored. The mutants resulted from alterations in at least two GSF chromosomal regions, one autosomal and one located on the distal half of the (p)-arm of the Y chromosome. The two mutations affected carpel development independently, each mutation showing incomplete penetrance and variegation, albeit at significantly different levels. During successive meiotic generations, a progressive increase in penetrance and a reduction in variegation levels were observed and quantified at the level of the Y-linked GSF (GSF-Y). Possible mechanisms are pr...

Genetics, 1999

White campion is a dioecious plant with heteromorphic X and Y sex chromosomes. In male plants, a ... more White campion is a dioecious plant with heteromorphic X and Y sex chromosomes. In male plants, a filamentous structure replaces the pistil, while in female plants the stamens degenerate early in flower development. Asexual (asx) mutants, cumulating the two developmental defects that characterize the sexual dimorphism in this species, were produced by gamma ray irradiation of pollen and screening in the M1 generation. The mutants harbor a novel type of mutation affecting an early function in sporogenous/parietal cell differentiation within the anther. The function is called stamen-promoting function (SPF). The mutants are shown to result from interstitial deletions on the Y chromosome. We present evidence that such deletions tentatively cover the central domain on the (p)-arm of the Y chromosome (Y2 region). By comparing stamen development in wild-type female and asx mutant flowers we show that they share the same block in anther development, which results in the production of vestig...

FEBS Open Bio, 2018

The nucleoplasm and nucleolus are the two main territories of the nucleus. While specific functio... more The nucleoplasm and nucleolus are the two main territories of the nucleus. While specific functions are associated with each of these territories (such as mRNA synthesis in the nucleoplasm and ribosomal rRNA synthesis in the nucleolus), some proteins are known to be located in both. Here, we investigated the molecular function of REBELOTE (RBL), an Arabidopsis thaliana protein previously characterized as a regulator of floral meristem termination. We show that RBL displays a dual localization, in the nucleolus and nucleoplasm. Moreover, we used direct and global approaches to demonstrate that RBL interacts with nucleic acid-binding proteins. It binds to the NOC proteins SWA2, AtNOC2 and AtNOC3 in both the nucleolus and nucleoplasm, and also to OBE1 and VFP3/ENAP1. Taking into account the identities of these RBL interactors, we hypothesise that RBL acts both in ribosomal biogenesis and in the regulation of gene expression.

The Lancet Planetary Health, 2018

The EMBO Journal, 1987

Communicated by M.van Montagu We have isolated a 1.5-kb plant DNA fragment (called insert 7) from... more Communicated by M.van Montagu We have isolated a 1.5-kb plant DNA fragment (called insert 7) from Nicotiana plumbaginifolia DNA that contains a protoplast-specific enhancer-like sequence. The presence of this sequence on a plasmid carrying a chimeric nos-npt-H gene conferring kanamycin resistance to plant cells, produces an overexpression of the npt-H gene during at least eight days after protoplast transformation. This effect on the expression of the nos promoter was independent of the orientation and was observed both on circular and linearized plasmids. On the contrary, insert 7 had no influence when present on another plasmid (in trans) in cotransformation experiments. The overexpression of the nos-npt-l gene due to the presence of insert 7 on the transforming plasmid is correlated with a higher level of synthesis of the corresponding RNA. Insert 7 did not affect the level of expression of the nos-npt-H gene in stably transformed cafli, or in regenerated plants. However, the overexpression was again detected in protoplasts prepared from leaves of stably transformed plants. This 1.5-kb plant DNA fragment contains highly repetitive DNA sequences, specific to N. plumbaginifolia. However, the enhancer-like activity is localized on a 600-bp unique sequence of insert 7. Insert 7 had no detectable effect on the transient expression of another gene, the nopaline synthase gene present at a longer distance on the same plasmid.

Biotechnology & Biotechnological Equipment, 2005

Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolut... more Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolution. Current studies have been based on fluorescent in situ hybridization (FISH). FISH in situ hybridization in conjucation with Ag-staining was used to map physically the 18S.26S multigene rRNA family in S. latifolia L. The 18S-5.8S-26S rRNA genes have been located on four pairs of Silene chromosomes. The pairs of majors rRNA sites on chromosome 5, 7, 9 and 10 are well known. Silver staining of nuclei and in situ hybridization analysis have previously indicated that additional rDNA sites may be present, but the presence of sites on a five chromosome pairs was unexpected. Using FISH in situ hybridization, we report a new fifth locous in S. latifolia and also confirm the nucleolus organizing region (Nor) by Ag-staining. We propose calling the new sites Nor-11. In situ hybridization is valuable for gene mapping, since it can detect presence of genes with a very wide range of copy number at different sites.

Plant Science Letters, 1977

Arabidopsis thaliana is one of the best studied plant model organisms. Besides cultivation in gre... more Arabidopsis thaliana is one of the best studied plant model organisms. Besides cultivation in greenhouses, cells of this plant can also be propagated in suspension cell culture. At7 is one such cell line that was established about 25 years ago. Here, we report the sequencing and the analysis of the At7 genome. Large scale duplications and deletions compared to the Columbia-0 (Col-0) reference sequence were detected. The number of deletions exceeds the number of insertions, thus indicating that a haploid genome size reduction is ongoing. Patterns of small sequence variants differ from the ones observed between A. thaliana accessions, e.g., the number of single nucleotide variants matches the number of insertions/deletions. RNA-Seq analysis reveals that disrupted alleles are less frequent in the transcriptome than the native ones.

Annals of Botany, 2011

† Background and Aims Bisexual flowers of Carica papaya range from highly regular flowers to morp... more † Background and Aims Bisexual flowers of Carica papaya range from highly regular flowers to morphs with various fusions of stamens to the ovary. Arabidopsis thaliana sup1 mutants have carpels replaced by chimeric carpel-stamen structures. Comparative analysis of stamen to carpel conversions in the two different plant systems was used to understand the stage and origin of carpeloidy when derived from stamen tissues, and consequently to understand how carpeloidy contributes to innovations in flower evolution. † Methods Floral development of bisexual flowers of Carica was studied by scanning electron microscopy and was compared with teratological sup mutants of A. thaliana. † Key Results In Carica development of bisexual flowers was similar to wild (unisexual) forms up to locule initiation. Feminization ranges from fusion of stamen tissue to the gynoecium to complete carpeloidy of antepetalous stamens. In A. thaliana, partial stamen feminization occurs exclusively at the flower apex, with normal stamens forming at the periphery. Such transformations take place relatively late in development, indicating strong developmental plasticity of most stamen tissues. These results are compared with evo-devo theories on flower bisexuality, as derived from unisexual ancestors. The Arabidopsis data highlight possible early evolutionary events in the acquisition of bisexuality by a patchy transformation of stamen parts into female parts linked to a flower axis-position effect. The Carica results highlight tissue-fusion mechanisms in angiosperms leading to carpeloidy once bisexual flowers have evolved. † Conclusions We show two different developmental routes leading to stamen to carpel conversions by late re-specification. The process may be a fundamental aspect of flower development that is hidden in most instances by developmental homeostasis.

L Le es s R Re es ss so ou ur rc ce es s-l le e g gr ra an nd d e en nj je eu u d de e l la a t t... more L Le es s R Re es ss so ou ur rc ce es s-l le e g gr ra an nd d e en nj je eu u d de e l la a t tr ra an ns si it ti io on n s so oc ci ié ét ta al le e e et t é éc co ol lo og gi iq qu ue e  I I.. N Ne eg gr ru ut ti iu u Biologiste, Directeur de l'Institut Michel Serres, ENS de Lyon D D.. C Co ou uv ve et t Professeur au Muséum National d'Histoire Naturelles et à l'école polytechnique,

Theoretical and Applied Genetics, 1990

Communicated by Yu. Gleba we feel confident in speculating that intergenomic recombination betwee... more Communicated by Yu. Gleba we feel confident in speculating that intergenomic recombination between N. plumbaginifolia and N. tabacum has occurred.

Theoretical and Applied Genetics, 1990

Nicotiana plumbaginifolia mutant, "Nia26," were fused with v-irradiated mesophyll protoplasts of ... more Nicotiana plumbaginifolia mutant, "Nia26," were fused with v-irradiated mesophyll protoplasts of Nicotiana sylvestris, V-42. Hybrid selection was based on complementation of NR deficiency by transfer of the donor NR gene to N. plumbaginifolia. Regenerated hybrids had different numbers of donor chromosomes in a tetraploid background of N. plumbaginifolia. The transfer and expression of different isozymes from the donor were also observed. Six self-fertile regenerants were obtained from 21 independently isolated cell colonies. Progeny analyses revealed: (1) the linkage of NR and shikimate dehydrogenase (ShDh); (2) a stabilization of the transmission rate of NR; and (3) the obtainment of mono-and disomic addition lines in the first and second progeny of the original regenerants. Southern hybridization analyses demonstrated unequivocally the presence of the NR gene from the donor partner in progeny plants.

Theoretical and Applied Genetics, 1984

Two S-(2-aminoethyl)L-cysteine (AEC) resistant lines were isolated by screening mutagenized proto... more Two S-(2-aminoethyl)L-cysteine (AEC) resistant lines were isolated by screening mutagenized protoplasts from diploid N. sylvestris plants. Both lines accumulated free lysine at levels 10 to 20-fold higher than in controls. Lysine overproduction and AEC-resistance were also expressed in plants regenerated from the variant Cultures. A feedback insensitive form of dihydrodipicolinate synthase (DHPS), the pathway specific control enzyme for lysine synthesis, was detected in callus cultures and leaf extracts from the resistant lines. Aspartate kinase (AK), the other key enzyme in the regulation of lysine biosynthesis, was unaltered in the mutants. Crosses with wild type plants indicated that the mutation conferring insensitivity to feedback in DHPS, with as result overproduction of lysine and resistance to AEC, was inherited as a single dominant nuclear gene.

The Plant Journal, 2004

We report a comparative analysis of cell proliferation patterns during Arabidopsis¯ower developme... more We report a comparative analysis of cell proliferation patterns during Arabidopsis¯ower development. Cell division was evaluated by a direct method, i.e. the 5-bromo-2 H-deoxyuridine (BrdU) incorporation/immunodetection procedure. BrdU patterns in wild-type plants were correlated with the expression pro®les of both several cell cycle genes involved in the control of the G 1 /S transition and cell cycle-related repressor genes, MSI4 and MSI5, encoding WD-repeat proteins. To evaluate how proliferation patterns arise with respect to boundaries and vice versa, the expression of a boundary gene, CUP SHAPED COTYLEDON (CUC)2, was determined. Combining these approaches, we demonstrate that boundaries between in¯orescence and oral meristems and between¯oral whorls are narrow bands of non-dividing cells. In addition, we show that negative and positive regulators of cell proliferation are simultaneously and continuously expressed in dividing meristematic domains, being excluded from boundary cells. Finally, BrdU incorporation and CUC2 in situ hybridisation patterns were analysed in two mutant backgrounds, agamous (ag)-1 and superman (sup)-1, in order to assess changes in boundary establishment and different levels of indeterminacy under conditions of altered proliferation at the¯oral meristem centre.

The EMBO Journal, 1999

Unlike the majority of flowering plants, which possess hermaphrodite flowers, white campion (Sile... more Unlike the majority of flowering plants, which possess hermaphrodite flowers, white campion (Silene latifolia) is dioecious and has flowers of two different sexes. The sex is determined by the combination of heteromorphic sex chromosomes: XX in females and XY in males. The Y chromosome of S.latifolia was microdissected to generate a Y-specific probe which was used to screen a young male flower cDNA library. We identified five genes which represent the first active genes to be cloned from a plant Y chromosome. Here we report a detailed analysis of one of these genes, SlY1 (S.latifolia Y-gene 1). SlY1 is expressed predominantly in male flowers. A closely related gene, SlX1, is predicted to be located on the X chromosome and is strongly expressed in both male and female flowers. SlY1 and SlX1 encode almost identical proteins containing WD repeats. Immunolocalization experiments showed that these proteins are localized in the nucleus, and that they are most abundant in cells that are actively dividing or beginning to differentiate. Interestingly, they do not accumulate in arrested sexual organs and represent potential targets for sex determination genes. These genes will permit investigation of the origin and evolution of sex chromosomes in plants.