Françoise Budar - Academia.edu (original) (raw)

Papers by Françoise Budar

Research paper thumbnail of Cytoplasmic Male Sterility

Research paper thumbnail of Data from: A meta-analysis of the strength and nature of cytoplasmic genetic effects

Genetic variation in cytoplasmic genomes (i.e. the mitochondrial genome in animals, and the combi... more Genetic variation in cytoplasmic genomes (i.e. the mitochondrial genome in animals, and the combined mitochondrial and chloroplast genomes in plants) was traditionally assumed to accumulate under a neutral equilibrium model. This view has, however, come under increasing challenge from studies that have experimentally linked cytoplasmic genetic effects to the expression of life history phenotypes. Such results suggest that genetic variance located within the cytoplasm might be of evolutionary importance and potentially involved in shaping population evolutionary trajectories. As a step towards assessing this assertion, here we conduct a formal meta-analytic review to quantitatively assess the extent to which cytoplasmic genetic effects contribute to phenotypic expression across animal and plant kingdoms. We report that cytoplasmic effect sizes are generally moderate in size and associated with variation across a range of factors. Specifically, cytoplasmic effects on morphological traits are generally larger than those on life history or metabolic traits. Cytoplasmic effect sizes estimated at the between-species scale (via interspecies mix-and-matching of cytoplasmic and nuclear genomes) are larger than those at the within-species scale. Furthermore, cytoplasmic effects tied to epistatic interactions with the nuclear genome tend to be stronger than additive cytoplasmic effects, at least when restricting the data set to gonochorous animal species. Our results thus confirm that cytoplasmic genetic variation is commonly tied to phenotypic expression across plants and animals, implicate the cytoplasmic–nuclear interaction as a key unit on which natural selection acts and generally suggest that the genetic variation that lies within the cytoplasm is likely to be entwined in adaptive evolutionary processes

Research paper thumbnail of APOK3, a pollen killer antidote in Arabidopsis thaliana

According to the principles of heredity, each parental allele of hybrids equally participates in ... more According to the principles of heredity, each parental allele of hybrids equally participates in the progeny. At some loci, however, it happens that one allele is favored to the expense of the other. Gamete killers are genetic systems where one allele (the killer) triggers the death of the gametes carrying the other (killed) allele. They have been found in many organisms, and are of major interest to understand mechanisms of evolution and speciation. Gamete killers are particularly prevalent in plants, where they can compromise crop breeding. Here, we deciphered a pollen killer in Arabidopsis thaliana by exploiting natural variation, de novo genomic sequencing and mutants, and analyzing segregations in crosses. We found that the killer allele carries an antidote gene flanked by two elements mandatory for the killing activity. We identified the gene encoding the antidote, a chimeric protein addressed to mitochondria. This gene appeared in the species by association of domains recruit...

Research paper thumbnail of Agrobacterium-Mediated Gene Transfer Results Mainly in Transgenic Plants Transmitting T-Dna as a Single Mendelian Factor

Genetics, 1986

Forty-four independent transformed tobacco plants were obtained from a cocultivation experiment w... more Forty-four independent transformed tobacco plants were obtained from a cocultivation experiment with Agrobacterium tumefaciens strains carrying modified Ti-plasmids. The transformed plants were either self-fertilized or crossed with nontransformed plants or with other transformed plants. The segregation of a phenotypic marker (kanamycin resistance) in the progenies of these plants was determined. In 40 cases out of 44, the segregation of the kanamycin resistance marker is consistent with Mendelian genetics. Among these 40 clones, 35 contain a single kanamycin resistance locus. The five others segregate two independent resistance loci. In two of the single insert clones, the segregation ratio after selfing indicates that the T-DNA insertion may have caused a recessive lethal mutation.

Research paper thumbnail of Novel cytonuclear combinations modify Arabidopsis seed physiology and vigor

The influence of intraspecific variation in cytoplasmic genomes and cytonuclear interactions on k... more The influence of intraspecific variation in cytoplasmic genomes and cytonuclear interactions on key seed traits that can impact adaptation and agriculture has not been thoroughly explored, so far. Here, dormancy, germination performance and longevity of seeds have been assessed in Arabidopsis plants with novel cytonuclear combinations that disrupt coadaptation between natural variants of nuclear and cytoplasmic genomes. Although all three traits were affected by cytonuclear reshuffling, the sensitivity of seed traits to cytoplasmic change was dependent on the nuclear background. Both deleterious and, more surprisingly, favorable effects of novel cytonuclear combinations (in comparison with the nuclear parent) were observed, suggesting suboptimal genetic combinations exist in natural populations for these traits. Significant changes on dormancy and germination performance due to specific cytonuclear interacting combinations mainly occurred in opposite directions, in accordance with t...

Research paper thumbnail of Cytonuclear interactions affect adaptive traits of the annual plant Arabidopsis thaliana in the field

Proceedings of the National Academy of Sciences, 2016

Significance As the centers of photosynthesis and respiration, chloroplasts and mitochondria play... more Significance As the centers of photosynthesis and respiration, chloroplasts and mitochondria play a crucial role in energy metabolism. Nuclear and cytoplasmic genomes are known to be coadapted at the species level, because organelle metabolism relies on the proper interaction of organelle-encoded and nuclear-encoded proteins. We explored the extent of cytonuclear coadaptation at the intraspecific level in the classic model plant Arabidopsis thaliana : we measured in a field experiment 28 adaptive whole-organism traits on cytolines developed by substituting cytoplasmic genomes among natural strains. Our results indicate that interactions between nuclear and cytoplasmic genomes shape natural variation for most of the traits we studied, suggesting that these interactions can affect the evolutionary dynamics of natural populations of A. thaliana .

Research paper thumbnail of Brassica Ogu-INRA Cytoplasmic Male Sterility: An Example of Successful Plant Somatic Fusion for Hybrid Seed Production

Somatic Genome Manipulation, 2015

Research paper thumbnail of Unveiling the molecular arms race between two conflicting genomes in cytoplasmic male sterility?

Trends in Plant Science, 2004

Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation. Chromosoma 110,... more Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation. Chromosoma 110, 559-569 24 Santos, A.P. et al. (2002) The architecture of interphase chromosomes and gene positioning are altered by changes in DNA methylation and histone acetylation.

Research paper thumbnail of The role of organelle genomes in plant adaptation

Plant Signaling & Behavior, 2011

Research paper thumbnail of Cytoplasmic Male Sterilities and Mitochondrial Gene Mutations in Plants

Plant Mitochondria

... Françoise Budar and Richard Berthomé ... When viable plants carrying recom-bined mitochondria... more ... Françoise Budar and Richard Berthomé ... When viable plants carrying recom-bined mitochondrial genomes can be regenerated, the most dramatic phenotypic ef-fects concern flower morphology and pollen production (Belliard et al., 1979; Leino et al., 2003; Zubko et al., 2003). ...

Research paper thumbnail of Cytonuclear Adaptation in Plants

Advances in Botanical Research, 2012

ABSTRACT Plants possess compartmentalized genomes that are distributed in the nucleus and in two ... more ABSTRACT Plants possess compartmentalized genomes that are distributed in the nucleus and in two organelles: the mitochondria (mt) and plastids (pt). The crucial functions of these organelles require interaction between products encoded by the organelle genome and the nucleus. Hence, coadaptation contributes to the evolution of plant genomes, leading to a cooperative coevolution between interacting gene products that are encoded in different compartments. In addition, the different modes of inheritance between the Mendelian nuclear genes and uniparental organelles create a genomic conflict that also contributes to shape the evolution of some mt and nuclear genes: those involved in cytonuclear male sterilities. Pentatricopeptide repeat proteins have been involved in the evolution of the mt-nuclear conflict, but are also suspected to participate in the cooperative coadaptation between the nuclear compartment and organelle genomes. Several lines of evidence indicate that organelle genetic variations contribute to plant adaptation to their environment. So far, very few studies have identified potentially adaptive organelle variants. Nevertheless, it is very likely that cytonuclear coadaptation interferes with cytoplasmic adaptation to the environment. Both phenomena must therefore be considered in future work aiming at a better understanding of the evolution of organelle genes and adaptive component.

Research paper thumbnail of Characterization of a radish introgression carrying the Ogura fertility restorer gene Rfo in rapeseed, using the Arabidopsis genome sequence and radish genetic mapping

Theoretical and Applied Genetics, 2003

Research paper thumbnail of Analyses of mitochondrial DNA structure and expression in three cytoplasmic male-sterile chicories originating from somatic hybridisation between fertile chicory and CMS sunflower protoplasts

Theoretical and Applied Genetics, 1999

Cytoplasmic male-sterile (CMS) chicories have been previously obtained by somatic hybridisation b... more Cytoplasmic male-sterile (CMS) chicories have been previously obtained by somatic hybridisation between fertile industrial chicory protoplasts and CMS sunflower protoplasts. In this study, we compared three different CMS chicory cybrids that originated from three different fusion events. The cybrids were backcrossed with different witloof chicories in order to transfer the three male-sterile cytoplasms from an industrial chicory nuclear environment to a witloof chicory nuclear context. Southern hybridisation, using different mitochondrial genes as probes, revealed that the three cybrid mitochondrial genomes were different and that they were stable throughout backcrossing generations regardless of the pollinator. However, pollinators were found to influence floral morphologies-with one being able to restore fertility-showing that nuclear context can affect the sterility of the cybrids. PCR and RFLP analyses revealed that the orf522 sequence, responsible for CMS in PET1 sunflower, was present in two out of the three cytoplasms studied, namely 411 and 523, but was absent from the other cytoplasm, 524. We thus concluded that orf522 is not responsible for CMS in the 524 cybrid. Although the orf522 gene is present in the 411 and 523 cytoplasms, it is probably not responsible for the sterile phenotype of these cybrids.

Research paper thumbnail of Cytoplasmic suppression of Ogura cytoplasmic male sterility in European natural populations of Raphanus raphanistrum

Theoretical and Applied Genetics, 2007

The Ogura cytoplasmic male sterility (CMS) of radish has been used for hybrid seed production in ... more The Ogura cytoplasmic male sterility (CMS) of radish has been used for hybrid seed production in radish and Brassica crops. It is the only CMS system occurring in wild populations for which the gene responsible for sterility and a restorer gene have been formally identified. In Japan, gynodioecious populations of radish carrying Ogura or an Ogura-related cytoplasm have been described. The occurrence of restorer genes for the Ogura CMS in wild radish (Raphanus raphanistrum) in France led us to search for the corresponding male sterility gene (orf138) in several natural populations in France, England and Lebanon. We detected the orf138 gene, by PCR, at low frequency, in three populations from France and one from Southern England. Further molecular characterization showed that these plants carried a cytoplasm closely related to the original Ogura cytoplasm, with a variant orf138 coding sequence, previously reported to be ancestral. We performed crosses with sterile and maintainer radish lines, to test the ability of this wild Ogura-related cytoplasm to induce sterility. Surprisingly, the European Ogura-related cytoplasm did not cause sterility. Northern blots and circular RT-PCR analyses showed that orf138 gene expression was impaired in these plants because of a novel cytoplasm-dependent transcript-processing site.

Research paper thumbnail of Characterization of Raphanus sativus Pentatricopeptide Repeat Proteins Encoded by the Fertility Restorer Locus for Ogura Cytoplasmic Male Sterility

The Plant Cell, 2008

Cytoplasmic male sterility is a maternally inherited trait in higher plants that prevents the pro... more Cytoplasmic male sterility is a maternally inherited trait in higher plants that prevents the production of functional pollen. Ogura cytoplasmic male sterility in radish (Raphanus sativus) is regulated by the orf138 mitochondrial locus. Male fertility can be restored when orf138 accumulation is suppressed by the nuclear Rfo locus, which consists of three genes putatively encoding highly similar pentatricopeptide repeat proteins (PPR-A, -B, and -C). We produced transgenic rapeseed (Brassica napus) plants separately expressing PPR-A and PPR-B and demonstrated that both encoded proteins accumulated preferentially in the anthers of young flower buds. Immunodetection of ORF138 showed that, unlike PPR-B, PPR-A had no effect on the synthesis of the sterility protein. Moreover, immunolocalization experiments indicated that complete elimination of ORF138 from the tapetum of anthers correlated with the restoration of fertility. Thus, the primary role of PPR-B in restoring fertility is to inhi...

Research paper thumbnail of The steady-state level of mRNA from the Ogura cytoplasmic male sterility locus in Brassica cybrids is determined post-transcriptionally by its 3' region

The EMBO Journal, 1997

Almost nothing is known about the mechan-We have investigated the control of the expression of is... more Almost nothing is known about the mechan-We have investigated the control of the expression of isms that control gene expression at this level. Like three different configurations of the mitochondrial gene chloroplast transcripts, plant mitochondrial mRNAs tend orf138, whose expression is correlated with Ogura to contain inverted repeat sequences in their 3Ј region that cytoplasmic male-sterility in rapeseed cybrids. These can fold into stem-loop structures (Bland et al., 1986; configurations, termed Nco2.5/13S, Nco2.7/13F and

Research paper thumbnail of A Cryptic Cytoplasmic Male Sterility Unveils a Possible Gynodioecious Past for Arabidopsis thaliana

PLoS ONE, 2013

Gynodioecy, the coexistence of hermaphrodites and females (i.e. male-sterile plants) in natural p... more Gynodioecy, the coexistence of hermaphrodites and females (i.e. male-sterile plants) in natural plant populations, most often results from polymorphism at genetic loci involved in a particular interaction between the nuclear and cytoplasmic genetic compartments (cytonuclear epistasis): cytoplasmic male sterility (CMS). Although CMS clearly contributes to the coevolution of involved nuclear loci and cytoplasmic genomes in gynodioecious species, the occurrence of CMS genetic factors in the absence of sexual polymorphism (cryptic CMS) is not easily detected and rarely taken in consideration. We found cryptic CMS in the model plant Arabidopsis thaliana after crossing distantly related accessions, Sha and Mr-0. Male sterility resulted from an interaction between the Sha cytoplasm and two Mr-0 genomic regions located on chromosome 1 and chromosome 3. Additional accessions with either nuclear sterility maintainers or sterilizing cytoplasms were identified from crosses with either Sha or Mr-0. By comparing two very closely related cytoplasms with different male-sterility inducing abilities, we identified a novel mitochondrial ORF, named orf117Sha, that is most likely the sterilizing factor of the Sha cytoplasm. The presence of orf117Sha was investigated in worldwide natural accessions. It was found mainly associated with a single chlorotype in accessions belonging to a clade predominantly originating from Central Asia. More than one-third of accessions from this clade carried orf117Sha, indicating that the sterilizing-inducing cytoplasm had spread in this lineage. We also report the coexistence of the sterilizing cytoplasm with a non-sterilizing cytoplasm at a small, local scale in a natural population; in addition a correlation between cytotype and nuclear haplotype was detected in this population. Our results suggest that this CMS system induced sexual polymorphism in A. thaliana populations, at the time when the species was mainly outcrossing.

Research paper thumbnail of pur4 Mutations Are Lethal to the Male, But Not the Female, Gametophyte and Affect Sporophyte Development in Arabidopsis

Research paper thumbnail of The Ogura sterility-inducing protein forms a large complex without interfering with the oxidative phosphorylation components in rapeseed mitochondria

Plant Molecular Biology, 2009

The Ogura cytoplasmic male sterility causing protein, ORF138, was found to be part of a complex w... more The Ogura cytoplasmic male sterility causing protein, ORF138, was found to be part of a complex with an apparent size of over 750 kDa in the inner membrane of mitochondria of sterile plants. ORF138 did not colocalize with any of the oxidative phosphorylation complexes, nor did its presence modify their apparent size or amount, compared to samples from fertile isogenic plants. We attempted to detect potential proteins or nucleic acids that could be involved in the large ORF138 complex by 2D PAGE, immunoprecipitation and nuclease treatments of native extracts. All our results suggest that the ORF138 protein is the main, if not only, component of this large complex. The capacities of complexes I, II, IV, and ATP synthase were identical in samples from sterile and fertile plants. Isolated mitochondria from sterile plants showed a higher oxygen consumption than those from fertile plants. In vivo respiration measurements suggest that the difference in O(2) consumption measured at the organelle level is compensated at the cell/tissue level, completely in leaves, but only partially in male reproductive organs.

Research paper thumbnail of Genetic evidence that the tryptophan 2-mono-oxygenase gene of Pseudomonas savastonoi is functionally equivalent to one of the T-DNA genes involved in plant tumour formation by Agrobacterium tumefaciens

Molecular and General Genetics MGG, 1985

The combined activities of the Agrobacterium tumefaciens T-DNA genes 1 and 2 are sufficient to in... more The combined activities of the Agrobacterium tumefaciens T-DNA genes 1 and 2 are sufficient to induce tumorous growth on several plants, by introducing a new auxin biosynthetic pathway in infected cells. We have isolated Nicotiana tabacum plants containing only gene 1 or gene 2. These plants, respectively called rG1 and rG2, grow and develop in a normal fashion, indicating that neither the gene 1 nor the gene 2 activity by itself interferes with the endogenous auxin metabolism in plants. Previous evidence indicated that the auxin biosynthetic pathway of Pseudomonas savastanoi and that proposed to be encoded by the T-DNA of Agrobacterium tumefaciens are similar. When rG2 plants were infected with non-oncogenic A. tumefaciens or Escherichia eoli strains that harbour the P. savastanoi iaaM gene (responsible for indole-3-acetamide synthesis) root and callus formation at the infection site was readily observed. This shows that the product of iaaM, indole-3-acetamide, is an in vivo substrate for the gene 2 encoded enzyme and supports the proposal that the gene 1-encoded enzyme is involved in the synthesis of indole-3acetamide in transformed plants. This result offers new insights in the evolution of bacteria and plants involved in pathogenic and symbiotic interactions.

Research paper thumbnail of Cytoplasmic Male Sterility

Research paper thumbnail of Data from: A meta-analysis of the strength and nature of cytoplasmic genetic effects

Genetic variation in cytoplasmic genomes (i.e. the mitochondrial genome in animals, and the combi... more Genetic variation in cytoplasmic genomes (i.e. the mitochondrial genome in animals, and the combined mitochondrial and chloroplast genomes in plants) was traditionally assumed to accumulate under a neutral equilibrium model. This view has, however, come under increasing challenge from studies that have experimentally linked cytoplasmic genetic effects to the expression of life history phenotypes. Such results suggest that genetic variance located within the cytoplasm might be of evolutionary importance and potentially involved in shaping population evolutionary trajectories. As a step towards assessing this assertion, here we conduct a formal meta-analytic review to quantitatively assess the extent to which cytoplasmic genetic effects contribute to phenotypic expression across animal and plant kingdoms. We report that cytoplasmic effect sizes are generally moderate in size and associated with variation across a range of factors. Specifically, cytoplasmic effects on morphological traits are generally larger than those on life history or metabolic traits. Cytoplasmic effect sizes estimated at the between-species scale (via interspecies mix-and-matching of cytoplasmic and nuclear genomes) are larger than those at the within-species scale. Furthermore, cytoplasmic effects tied to epistatic interactions with the nuclear genome tend to be stronger than additive cytoplasmic effects, at least when restricting the data set to gonochorous animal species. Our results thus confirm that cytoplasmic genetic variation is commonly tied to phenotypic expression across plants and animals, implicate the cytoplasmic–nuclear interaction as a key unit on which natural selection acts and generally suggest that the genetic variation that lies within the cytoplasm is likely to be entwined in adaptive evolutionary processes

Research paper thumbnail of APOK3, a pollen killer antidote in Arabidopsis thaliana

According to the principles of heredity, each parental allele of hybrids equally participates in ... more According to the principles of heredity, each parental allele of hybrids equally participates in the progeny. At some loci, however, it happens that one allele is favored to the expense of the other. Gamete killers are genetic systems where one allele (the killer) triggers the death of the gametes carrying the other (killed) allele. They have been found in many organisms, and are of major interest to understand mechanisms of evolution and speciation. Gamete killers are particularly prevalent in plants, where they can compromise crop breeding. Here, we deciphered a pollen killer in Arabidopsis thaliana by exploiting natural variation, de novo genomic sequencing and mutants, and analyzing segregations in crosses. We found that the killer allele carries an antidote gene flanked by two elements mandatory for the killing activity. We identified the gene encoding the antidote, a chimeric protein addressed to mitochondria. This gene appeared in the species by association of domains recruit...

Research paper thumbnail of Agrobacterium-Mediated Gene Transfer Results Mainly in Transgenic Plants Transmitting T-Dna as a Single Mendelian Factor

Genetics, 1986

Forty-four independent transformed tobacco plants were obtained from a cocultivation experiment w... more Forty-four independent transformed tobacco plants were obtained from a cocultivation experiment with Agrobacterium tumefaciens strains carrying modified Ti-plasmids. The transformed plants were either self-fertilized or crossed with nontransformed plants or with other transformed plants. The segregation of a phenotypic marker (kanamycin resistance) in the progenies of these plants was determined. In 40 cases out of 44, the segregation of the kanamycin resistance marker is consistent with Mendelian genetics. Among these 40 clones, 35 contain a single kanamycin resistance locus. The five others segregate two independent resistance loci. In two of the single insert clones, the segregation ratio after selfing indicates that the T-DNA insertion may have caused a recessive lethal mutation.

Research paper thumbnail of Novel cytonuclear combinations modify Arabidopsis seed physiology and vigor

The influence of intraspecific variation in cytoplasmic genomes and cytonuclear interactions on k... more The influence of intraspecific variation in cytoplasmic genomes and cytonuclear interactions on key seed traits that can impact adaptation and agriculture has not been thoroughly explored, so far. Here, dormancy, germination performance and longevity of seeds have been assessed in Arabidopsis plants with novel cytonuclear combinations that disrupt coadaptation between natural variants of nuclear and cytoplasmic genomes. Although all three traits were affected by cytonuclear reshuffling, the sensitivity of seed traits to cytoplasmic change was dependent on the nuclear background. Both deleterious and, more surprisingly, favorable effects of novel cytonuclear combinations (in comparison with the nuclear parent) were observed, suggesting suboptimal genetic combinations exist in natural populations for these traits. Significant changes on dormancy and germination performance due to specific cytonuclear interacting combinations mainly occurred in opposite directions, in accordance with t...

Research paper thumbnail of Cytonuclear interactions affect adaptive traits of the annual plant Arabidopsis thaliana in the field

Proceedings of the National Academy of Sciences, 2016

Significance As the centers of photosynthesis and respiration, chloroplasts and mitochondria play... more Significance As the centers of photosynthesis and respiration, chloroplasts and mitochondria play a crucial role in energy metabolism. Nuclear and cytoplasmic genomes are known to be coadapted at the species level, because organelle metabolism relies on the proper interaction of organelle-encoded and nuclear-encoded proteins. We explored the extent of cytonuclear coadaptation at the intraspecific level in the classic model plant Arabidopsis thaliana : we measured in a field experiment 28 adaptive whole-organism traits on cytolines developed by substituting cytoplasmic genomes among natural strains. Our results indicate that interactions between nuclear and cytoplasmic genomes shape natural variation for most of the traits we studied, suggesting that these interactions can affect the evolutionary dynamics of natural populations of A. thaliana .

Research paper thumbnail of Brassica Ogu-INRA Cytoplasmic Male Sterility: An Example of Successful Plant Somatic Fusion for Hybrid Seed Production

Somatic Genome Manipulation, 2015

Research paper thumbnail of Unveiling the molecular arms race between two conflicting genomes in cytoplasmic male sterility?

Trends in Plant Science, 2004

Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation. Chromosoma 110,... more Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation. Chromosoma 110, 559-569 24 Santos, A.P. et al. (2002) The architecture of interphase chromosomes and gene positioning are altered by changes in DNA methylation and histone acetylation.

Research paper thumbnail of The role of organelle genomes in plant adaptation

Plant Signaling & Behavior, 2011

Research paper thumbnail of Cytoplasmic Male Sterilities and Mitochondrial Gene Mutations in Plants

Plant Mitochondria

... Françoise Budar and Richard Berthomé ... When viable plants carrying recom-bined mitochondria... more ... Françoise Budar and Richard Berthomé ... When viable plants carrying recom-bined mitochondrial genomes can be regenerated, the most dramatic phenotypic ef-fects concern flower morphology and pollen production (Belliard et al., 1979; Leino et al., 2003; Zubko et al., 2003). ...

Research paper thumbnail of Cytonuclear Adaptation in Plants

Advances in Botanical Research, 2012

ABSTRACT Plants possess compartmentalized genomes that are distributed in the nucleus and in two ... more ABSTRACT Plants possess compartmentalized genomes that are distributed in the nucleus and in two organelles: the mitochondria (mt) and plastids (pt). The crucial functions of these organelles require interaction between products encoded by the organelle genome and the nucleus. Hence, coadaptation contributes to the evolution of plant genomes, leading to a cooperative coevolution between interacting gene products that are encoded in different compartments. In addition, the different modes of inheritance between the Mendelian nuclear genes and uniparental organelles create a genomic conflict that also contributes to shape the evolution of some mt and nuclear genes: those involved in cytonuclear male sterilities. Pentatricopeptide repeat proteins have been involved in the evolution of the mt-nuclear conflict, but are also suspected to participate in the cooperative coadaptation between the nuclear compartment and organelle genomes. Several lines of evidence indicate that organelle genetic variations contribute to plant adaptation to their environment. So far, very few studies have identified potentially adaptive organelle variants. Nevertheless, it is very likely that cytonuclear coadaptation interferes with cytoplasmic adaptation to the environment. Both phenomena must therefore be considered in future work aiming at a better understanding of the evolution of organelle genes and adaptive component.

Research paper thumbnail of Characterization of a radish introgression carrying the Ogura fertility restorer gene Rfo in rapeseed, using the Arabidopsis genome sequence and radish genetic mapping

Theoretical and Applied Genetics, 2003

Research paper thumbnail of Analyses of mitochondrial DNA structure and expression in three cytoplasmic male-sterile chicories originating from somatic hybridisation between fertile chicory and CMS sunflower protoplasts

Theoretical and Applied Genetics, 1999

Cytoplasmic male-sterile (CMS) chicories have been previously obtained by somatic hybridisation b... more Cytoplasmic male-sterile (CMS) chicories have been previously obtained by somatic hybridisation between fertile industrial chicory protoplasts and CMS sunflower protoplasts. In this study, we compared three different CMS chicory cybrids that originated from three different fusion events. The cybrids were backcrossed with different witloof chicories in order to transfer the three male-sterile cytoplasms from an industrial chicory nuclear environment to a witloof chicory nuclear context. Southern hybridisation, using different mitochondrial genes as probes, revealed that the three cybrid mitochondrial genomes were different and that they were stable throughout backcrossing generations regardless of the pollinator. However, pollinators were found to influence floral morphologies-with one being able to restore fertility-showing that nuclear context can affect the sterility of the cybrids. PCR and RFLP analyses revealed that the orf522 sequence, responsible for CMS in PET1 sunflower, was present in two out of the three cytoplasms studied, namely 411 and 523, but was absent from the other cytoplasm, 524. We thus concluded that orf522 is not responsible for CMS in the 524 cybrid. Although the orf522 gene is present in the 411 and 523 cytoplasms, it is probably not responsible for the sterile phenotype of these cybrids.

Research paper thumbnail of Cytoplasmic suppression of Ogura cytoplasmic male sterility in European natural populations of Raphanus raphanistrum

Theoretical and Applied Genetics, 2007

The Ogura cytoplasmic male sterility (CMS) of radish has been used for hybrid seed production in ... more The Ogura cytoplasmic male sterility (CMS) of radish has been used for hybrid seed production in radish and Brassica crops. It is the only CMS system occurring in wild populations for which the gene responsible for sterility and a restorer gene have been formally identified. In Japan, gynodioecious populations of radish carrying Ogura or an Ogura-related cytoplasm have been described. The occurrence of restorer genes for the Ogura CMS in wild radish (Raphanus raphanistrum) in France led us to search for the corresponding male sterility gene (orf138) in several natural populations in France, England and Lebanon. We detected the orf138 gene, by PCR, at low frequency, in three populations from France and one from Southern England. Further molecular characterization showed that these plants carried a cytoplasm closely related to the original Ogura cytoplasm, with a variant orf138 coding sequence, previously reported to be ancestral. We performed crosses with sterile and maintainer radish lines, to test the ability of this wild Ogura-related cytoplasm to induce sterility. Surprisingly, the European Ogura-related cytoplasm did not cause sterility. Northern blots and circular RT-PCR analyses showed that orf138 gene expression was impaired in these plants because of a novel cytoplasm-dependent transcript-processing site.

Research paper thumbnail of Characterization of Raphanus sativus Pentatricopeptide Repeat Proteins Encoded by the Fertility Restorer Locus for Ogura Cytoplasmic Male Sterility

The Plant Cell, 2008

Cytoplasmic male sterility is a maternally inherited trait in higher plants that prevents the pro... more Cytoplasmic male sterility is a maternally inherited trait in higher plants that prevents the production of functional pollen. Ogura cytoplasmic male sterility in radish (Raphanus sativus) is regulated by the orf138 mitochondrial locus. Male fertility can be restored when orf138 accumulation is suppressed by the nuclear Rfo locus, which consists of three genes putatively encoding highly similar pentatricopeptide repeat proteins (PPR-A, -B, and -C). We produced transgenic rapeseed (Brassica napus) plants separately expressing PPR-A and PPR-B and demonstrated that both encoded proteins accumulated preferentially in the anthers of young flower buds. Immunodetection of ORF138 showed that, unlike PPR-B, PPR-A had no effect on the synthesis of the sterility protein. Moreover, immunolocalization experiments indicated that complete elimination of ORF138 from the tapetum of anthers correlated with the restoration of fertility. Thus, the primary role of PPR-B in restoring fertility is to inhi...

Research paper thumbnail of The steady-state level of mRNA from the Ogura cytoplasmic male sterility locus in Brassica cybrids is determined post-transcriptionally by its 3' region

The EMBO Journal, 1997

Almost nothing is known about the mechan-We have investigated the control of the expression of is... more Almost nothing is known about the mechan-We have investigated the control of the expression of isms that control gene expression at this level. Like three different configurations of the mitochondrial gene chloroplast transcripts, plant mitochondrial mRNAs tend orf138, whose expression is correlated with Ogura to contain inverted repeat sequences in their 3Ј region that cytoplasmic male-sterility in rapeseed cybrids. These can fold into stem-loop structures (Bland et al., 1986; configurations, termed Nco2.5/13S, Nco2.7/13F and

Research paper thumbnail of A Cryptic Cytoplasmic Male Sterility Unveils a Possible Gynodioecious Past for Arabidopsis thaliana

PLoS ONE, 2013

Gynodioecy, the coexistence of hermaphrodites and females (i.e. male-sterile plants) in natural p... more Gynodioecy, the coexistence of hermaphrodites and females (i.e. male-sterile plants) in natural plant populations, most often results from polymorphism at genetic loci involved in a particular interaction between the nuclear and cytoplasmic genetic compartments (cytonuclear epistasis): cytoplasmic male sterility (CMS). Although CMS clearly contributes to the coevolution of involved nuclear loci and cytoplasmic genomes in gynodioecious species, the occurrence of CMS genetic factors in the absence of sexual polymorphism (cryptic CMS) is not easily detected and rarely taken in consideration. We found cryptic CMS in the model plant Arabidopsis thaliana after crossing distantly related accessions, Sha and Mr-0. Male sterility resulted from an interaction between the Sha cytoplasm and two Mr-0 genomic regions located on chromosome 1 and chromosome 3. Additional accessions with either nuclear sterility maintainers or sterilizing cytoplasms were identified from crosses with either Sha or Mr-0. By comparing two very closely related cytoplasms with different male-sterility inducing abilities, we identified a novel mitochondrial ORF, named orf117Sha, that is most likely the sterilizing factor of the Sha cytoplasm. The presence of orf117Sha was investigated in worldwide natural accessions. It was found mainly associated with a single chlorotype in accessions belonging to a clade predominantly originating from Central Asia. More than one-third of accessions from this clade carried orf117Sha, indicating that the sterilizing-inducing cytoplasm had spread in this lineage. We also report the coexistence of the sterilizing cytoplasm with a non-sterilizing cytoplasm at a small, local scale in a natural population; in addition a correlation between cytotype and nuclear haplotype was detected in this population. Our results suggest that this CMS system induced sexual polymorphism in A. thaliana populations, at the time when the species was mainly outcrossing.

Research paper thumbnail of pur4 Mutations Are Lethal to the Male, But Not the Female, Gametophyte and Affect Sporophyte Development in Arabidopsis

Research paper thumbnail of The Ogura sterility-inducing protein forms a large complex without interfering with the oxidative phosphorylation components in rapeseed mitochondria

Plant Molecular Biology, 2009

The Ogura cytoplasmic male sterility causing protein, ORF138, was found to be part of a complex w... more The Ogura cytoplasmic male sterility causing protein, ORF138, was found to be part of a complex with an apparent size of over 750 kDa in the inner membrane of mitochondria of sterile plants. ORF138 did not colocalize with any of the oxidative phosphorylation complexes, nor did its presence modify their apparent size or amount, compared to samples from fertile isogenic plants. We attempted to detect potential proteins or nucleic acids that could be involved in the large ORF138 complex by 2D PAGE, immunoprecipitation and nuclease treatments of native extracts. All our results suggest that the ORF138 protein is the main, if not only, component of this large complex. The capacities of complexes I, II, IV, and ATP synthase were identical in samples from sterile and fertile plants. Isolated mitochondria from sterile plants showed a higher oxygen consumption than those from fertile plants. In vivo respiration measurements suggest that the difference in O(2) consumption measured at the organelle level is compensated at the cell/tissue level, completely in leaves, but only partially in male reproductive organs.

Research paper thumbnail of Genetic evidence that the tryptophan 2-mono-oxygenase gene of Pseudomonas savastonoi is functionally equivalent to one of the T-DNA genes involved in plant tumour formation by Agrobacterium tumefaciens

Molecular and General Genetics MGG, 1985

The combined activities of the Agrobacterium tumefaciens T-DNA genes 1 and 2 are sufficient to in... more The combined activities of the Agrobacterium tumefaciens T-DNA genes 1 and 2 are sufficient to induce tumorous growth on several plants, by introducing a new auxin biosynthetic pathway in infected cells. We have isolated Nicotiana tabacum plants containing only gene 1 or gene 2. These plants, respectively called rG1 and rG2, grow and develop in a normal fashion, indicating that neither the gene 1 nor the gene 2 activity by itself interferes with the endogenous auxin metabolism in plants. Previous evidence indicated that the auxin biosynthetic pathway of Pseudomonas savastanoi and that proposed to be encoded by the T-DNA of Agrobacterium tumefaciens are similar. When rG2 plants were infected with non-oncogenic A. tumefaciens or Escherichia eoli strains that harbour the P. savastanoi iaaM gene (responsible for indole-3-acetamide synthesis) root and callus formation at the infection site was readily observed. This shows that the product of iaaM, indole-3-acetamide, is an in vivo substrate for the gene 2 encoded enzyme and supports the proposal that the gene 1-encoded enzyme is involved in the synthesis of indole-3acetamide in transformed plants. This result offers new insights in the evolution of bacteria and plants involved in pathogenic and symbiotic interactions.