Contributions to the Yearbook of the Max Planck Society

2019

  • Epigenetic information storage in plants

    2019 Krause, Kristin; Coupland, George; Turck, Franziska
    An epigenetic memory determines how strongly genes are expressed. Polycomb Group protein complexes stably shut down genes by compacting the packaging material of DNA. Recent studies in plants showed that two different and short DNA sequences, called teloboxes and RY motifs, are involved in this epigenetic process. Genes that are under epigenetic regulation are enriched in both motifs, often in combination. Specialized transcription factors, which recognize teloboxes and RY motifs, also directly bind to building blocks of the Polycomb Group and thus stabilize the memory of target genes.
  • Plants rely on their microbiome to protect themselves from pathogens

    2019 Thiergart, Thorsten; Getzke, Felix; Hacquard, Stéphane
    Fungi and other filamentous microbial eukaryotes, i.e. oomycetes, cause many devastating plant diseases worldwide and are responsible for up to 10% of crop losses. Over the last decade, pesticide application, breeding for plant disease resistance or genetic manipulation of plant immune components have been primarily used to control microbial diseases. However, recent findings indicate that bacterial commensals living benignly inside or at the surface of plant root tissues can confer extended immune functions to the plant host, thereby restricting infection by filamentous microbes.

2018

  • Learning how barley flowers release pollen to bring on the agriculture of the future

    2018 Acosta, Ivan F.; Przybyl, Marine
    To improve crop quality and yield, breeders need to control the fertility of stamens, the male organs that produce pollen within sacs called anthers. For example, it would be ideal to manipulate at will the release of pollen from anthers. However, this firstly requires a detailed understanding of how anther cells themselves activate pollen release. In barley, this activation seems to be triggered by the phytohormone auxin and requires enzymes to separate specific cells from each other to finally open the anthers.
  • Epigenetic information storage in plants

    2018 Krause, Kristin; Coupland, George; Turck, Franziska
    An epigenetic memory determines how strongly genes are expressed. Polycomb Group protein complexes stably shut down genes by compacting the packaging material of DNA. Recent studies in plants showed that two different and short DNA sequences, called teloboxes and RY motifs, are involved in this epigenetic process. Genes that are under epigenetic regulation are enriched in both motifs, often in combination. Specialized transcription factors, which recognize teloboxes and RY motifs, also directly bind to building blocks of the Polycomb Group and thus stabilize the memory of target genes.

2017

  • Plant boundary zones initiate development of new meristems

    2017 Mulki, Muhammad Aman; Rossmann, Susanne; Theres, Klaus
    Boundary zones were previously seen as physical barriers that separate plant tissues and thus allow the development of functional organs. However, recent studies revealed that boundaries, like those between the shoot apical meristem and leaf primordia and those between leaflets, also serve as launching pads for secondary meristem formation and play an important role in determining plant architecture. Interestingly, establishment of boundary zones during shoot branching and complex leaf development is regulated by homologous genes.
  • Learning how barley flowers release pollen to bring on the agriculture of the future

    2017 Acosta, Ivan F.; Przybyl, Marine
    To improve crop quality and yield, breeders need to control the fertility of stamens, the male organs that produce pollen within sacs called anthers. For example, it would be ideal to manipulate at will the release of pollen from anthers. However, this firstly requires a detailed understanding of how anther cells themselves activate pollen release. In barley, this activation seems to be triggered by the phytohormone auxin and requires enzymes to separate specific cells from each other to finally open the anthers.

2016

  • Robustness and tunability of the plant immune system

    2016 Tsuda, Kenichi; Berens, Matthias L.
    Plants sense microbial molecules to trigger innate immunity for protection from pathogens. However, microbes have evolved broad virulence factors that interfere with plant immune components. Therefore, immune mechanisms must be robust to cope with microbial perturbations. In addition, since too much immune response is detrimental for plant fitness, plant immune responses need to be tuned. The scientists study how plant immune signaling networks achieve the properties robustness and tunability using molecular genetics, genomics and computational modeling.
  • Plant boundary zones initiate development of new meristems

    2016 Mulki, Muhammad Aman; Rossmann, Susanne; Theres, Klaus
    Boundary zones were previously seen as physical barriers that separate plant tissues and thus allow the development of functional organs. However, recent studies revealed that boundaries, like those between the shoot apical meristem and leaf primordia and those between leaflets, also serve as launching pads for secondary meristem formation and play an important role in determining plant architecture. Interestingly, establishment of boundary zones during shoot branching and complex leaf development is regulated by homologous genes.

2015

  • Developing the next generation of algorithms to understand the impact of the genotype on the phenotype

    2015 Willing, Eva-Maria; Schneeberger, Korbinian
    Individual genetic alterations can have direct impact on the phenotypes of the respective organisms. Such mutations can be useful for functional annotation of the respective regions of the genome and can be found between wildtype and mutant genomes, between distinct individuals of the same species, and between the genomic sequences of diverse species. The group develops new approaches to identify and to distinguish such differences from all other changes that do not affect the phenotypes.
  • Exploring the role of protein post-translational modifications in the regulation of plant metabolism

    2015 Finkemeier, Iris
    Depending on the environmental conditions, plants can rapidly alter their metabolism. Post-translational modification of proteins seems to play key roles during this adaptation. Reversible acetylation of lysine residues in proteins has recently emerged as post-translational modification controlling many important cellular functions beyond transcription. The identification of acetylation sites on metabolic enzymes in plants is a first step to uncover its physiological role in metabolism.
  • Robustness and tunability of the plant immune system

    2015 Tsuda, Kenichi; Berens, Matthias L.
    Plants sense microbial molecules to trigger innate immunity for protection from pathogens. However, microbes have evolved broad virulence factors that interfere with plant immune components. Therefore, immune mechanisms must be robust to cope with microbial perturbations. In addition, since too much immune response is detrimental for plant fitness, plant immune responses need to be tuned. The scientists study how plant immune signaling networks achieve the properties robustness and tunability using molecular genetics, genomics and computational modeling.

2014

  • Meristem specific expression of epigenetic regulators facilitates inactivation of transposable elements in Arabidopsis thaliana

    2014 Pecinka, Ales; Finke, Andreas

    Due to their potential risk for the genome integrity and thus the viability of an organism, transposable elements are kept inactive. Among others, the mechanism of RNA-directed DNA methylation facilitates this inactivation in plants. Recent investigations discovered a new shoot apical meristem specific function of this mechanism. It reinforces silencing of these elements during the early phase of vegetative growth and counteracts their drug-induced activation. It furthermore provides a checkpoint for correct epigenetic inheritance during the transition from vegetative to reproductive phase.

  • The biomechanics of morphogenesis

    2014 Smith, Richard S.
    Morphogenesis and growth are processes driven by genetic and signaling networks. Although many genetic components controlling plant organ shape have been identified, how they control the mechanical properties of cells remains elusive. In animal systems recent studies have shown that mechanical forces can feed back on genetic programs and even appear to be capable of influencing cell fate. Do such feedbacks exist in plants? What is the role of mechanics in morphogenesis? We address these questions by combining the expertise of physicists, biologists and computational modelers.
  • Exploring the role of protein post-translational modifications in the regulation of plant metabolism

    2014 Finkemeier, Iris
    Depending on the environmental conditions, plants can rapidly alter their metabolism. Post-translational modification of proteins seems to play key roles during this adaptation. Reversible acetylation of lysine residues in proteins has recently emerged as post-translational modification controlling many important cellular functions beyond transcription. The identification of acetylation sites on metabolic enzymes in plants is a first step to uncover its physiological role in metabolism.
  • Developing the next generation of algorithms to understand the impact of the genotype on the phenotype

    2014 Willing, Eva-Maria; Schneeberger, Korbinian
    Individual genetic alterations can have direct impact on the phenotypes of the respective organisms. Such mutations can be useful for functional annotation of the respective regions of the genome and can be found between wildtype and mutant genomes, between distinct individuals of the same species, and between the genomic sequences of diverse species. The group develops new approaches to identify and to distinguish such differences from all other changes that do not affect the phenotypes.

2013

  • Regulatory roles of plant TFIIH protein kinases

    2013 Koncz, Csaba

    RNA polymerase II transcribes protein coding and several classes of regulatory RNAs in multicellular organisms. The C-terminal domain of the RNAPII largest subunit, RNAPII-CTD, carries conserved heptapeptide repeats that are phosphorylated at different residues by a protein kinase cascade in Arabidopsis. Recent studies start to reveal how phosphorylation of the RNAPII-CTD by TFIIH-associated protein kinases regulates growth and development via coordinated control of transcription, cell cycle and biogenesis of microRNAs and small silencing siRNAs.

  • Cooperative threat: How interactions with associated organisms increase plant pathogen fitness

    2013 Kemen, Eric
    New plant diseases emerge regularly being a threat for food security. Some pathogens cause epidemics on living plants only and are called biotrophs. Comparative genomics revealed a loss of essential metabolic pathways leading to biotrophy. However, gene loss is only possible due to the ability to suppress host defense. Defense suppression and adaptability requires a large gene pool that is acquired by sexual recombination or interaction with other organisms. To get a comprehensive view on how new pathogens emerge it is important to dissect their interaction within natural habitats.
  • The biomechanics of morphogenesis

    2013 Smith, Richard S.
    Morphogenesis and growth are processes driven by genetic and signaling networks. Although many genetic components controlling plant organ shape have been identified, how they control the mechanical properties of cells remains elusive. In animal systems recent studies have shown that mechanical forces can feed back on genetic programs and even appear to be capable of influencing cell fate. Do such feedbacks exist in plants? What is the role of mechanics in morphogenesis? We address these questions by combining the expertise of physicists, biologists and computational modelers.
  • Meristem specific expression of epigenetic regulators facilitates inactivation of transposable elements in Arabidopsis thaliana

    2013 Pecinka, Ales; Finke, Andreas

    Due to their potential risk for the genome integrity and thus the viability of an organism, transposable elements are kept inactive. Among others, the mechanism of RNA-directed DNA methylation facilitates this inactivation in plants. Recent investigations discovered a new shoot apical meristem specific function of this mechanism. It reinforces silencing of these elements during the early phase of vegetative growth and counteracts their drug-induced activation. It furthermore provides a checkpoint for correct epigenetic inheritance during the transition from vegetative to reproductive phase.

2012

  • The makings of a robust plant immune system

    2012 Parker, Jane E.
    Plants display remarkable robustness against attempted pathogen infection and in their natural environment disease is the exception. Analysis of Arabidopsis plants is illuminating some fundamental processes by which plants recognize and resist microbial pathogen invasion. What emerges from recent studies is a set of distinct immune response branches in different parts of the host cell which are strictly coordinated to produce effective immunity.
  • Molecular basis and diagnostics of complex traits in potato as an example for crop plants

    2012 Gebhardt, Christiane
    Many traits that play important roles in plant breeding are complex, meaning that they are controlled by multiple genetic and environmental factors. Knowledge of the corresponding genes facilitates early diagnoses of complex traits and thereby increases the efficiency and precision of breeding new varieties of crop plants. To identify such genes, association-studies for complex traits of potato were conducted at the institute. Highly significant associations were identified between candidate genes and complex traits such as resistance to potato late blight disease.
  • Regulatory roles of plant TFIIH protein kinases

    2012 Koncz, Csaba

    RNA polymerase II transcribes protein coding and several classes of regulatory RNAs in multicellular organisms. The C-terminal domain of the RNAPII largest subunit, RNAPII-CTD, carries conserved heptapeptide repeats that are phosphorylated at different residues by a protein kinase cascade in Arabidopsis. Recent studies start to reveal how phosphorylation of the RNAPII-CTD by TFIIH-associated protein kinases regulates growth and development via coordinated control of transcription, cell cycle and biogenesis of microRNAs and small silencing siRNAs.

  • Cooperative threat: How interactions with associated organisms increase plant pathogen fitness

    2012 Kemen, Eric
    New plant diseases emerge regularly being a threat for food security. Some pathogens cause epidemics on living plants only and are called biotrophs. Comparative genomics revealed a loss of essential metabolic pathways leading to biotrophy. However, gene loss is only possible due to the ability to suppress host defense. Defense suppression and adaptability requires a large gene pool that is acquired by sexual recombination or interaction with other organisms. To get a comprehensive view on how new pathogens emerge it is important to dissect their interaction within natural habitats.

2011

  • The sleeping and waking of plant seeds

    2011 Zöll, Christian; Soppe, Wim J. J.
    Viable plant seeds are not always able to germinate and can cycle between a sleeping (dormant) and awake (non-dormant) state. Dormancy prevents germination during unfavourable seasons, an ability that has been lost in most of our crop species. The molecular regulation of seed dormancy is largely unknown. The Seed Dormancy Group has identified components of this control by isolating seed dormancy genes.
  • Developing biometrical methods to examine the genetic architecture of quantitative traits in crop plants

    2011 Stich, Benjamin
    Most traits which are important for fitness and agricultural value of crops are so-called quantitative traits. A large number of genes which interact with each other and are influenced by environmental factors contribute to variation of these traits. Understanding the genetic architecture of quantitative traits is not only important with respect to basic science but will also dramatically facilitate practical plant breeding.
  • The makings of a robust plant immune system

    2011 Parker, Jane E.
    Plants display remarkable robustness against attempted pathogen infection and in their natural environment disease is the exception. Analysis of Arabidopsis plants is illuminating some fundamental processes by which plants recognize and resist microbial pathogen invasion. What emerges from recent studies is a set of distinct immune response branches in different parts of the host cell which are strictly coordinated to produce effective immunity.
  • Molecular basis and diagnostics of complex traits in potato as an example for crop plants

    2011 Gebhardt, Christiane
    Many traits that play important roles in plant breeding are complex, meaning that they are controlled by multiple genetic and environmental factors. Knowledge of the corresponding genes facilitates early diagnoses of complex traits and thereby increases the efficiency and precision of breeding new varieties of crop plants. To identify such genes, association-studies for complex traits of potato were conducted at the institute. Highly significant associations were identified between candidate genes and complex traits such as resistance to potato late blight disease.

2010

  • Chromatin structure and gene control

    2010 Turck, Franziska
    Each cell of higher organisms contains a nucleus where the genetic material is tightly packed. In order to utilize genes, parts of the genetic material need to be unpacked, and protein complexes are involved in the process. Other protein complexes, conversely, function to prevent access to genes disabling gene expression.
  • Making connections: Data integration in biology

    2010 Schoof, Heiko
    Modern molecular biology employs high-throughput methods, for example to determine genome sequences. Their analysis and interpretation increasingly requires integration of heterogeneous data. Standards for access to biological data and web service technologies can facilitate automated finding and invocation of bioinformatics resources.
  • The sleeping and waking of plant seeds

    2010 Zöll, Christian; Soppe, Wim J. J.
    Viable plant seeds are not always able to germinate and can cycle between a sleeping (dormant) and awake (non-dormant) state. Dormancy prevents germination during unfavourable seasons, an ability that has been lost in most of our crop species. The molecular regulation of seed dormancy is largely unknown. The Seed Dormancy Group has identified components of this control by isolating seed dormancy genes.
  • Developing biometrical methods to examine the genetic architecture of quantitative traits in crop plants

    2010 Stich, Benjamin
    Most traits which are important for fitness and agricultural value of crops are so-called quantitative traits. A large number of genes which interact with each other and are influenced by environmental factors contribute to variation of these traits. Understanding the genetic architecture of quantitative traits is not only important with respect to basic science but will also dramatically facilitate practical plant breeding.

2009

  • Are MADS-box genes a key to the understanding of the development and evolution of land plant gametophytes?

    2009 Verelst, Wim; Münster, Thomas
    MIKC* MADS-box proteins constitute a regulatory network controlling important processes in pollen development of Arabidopsis thaliana. Comparative analysis of function, evolution, and systems biology of the MIKC* transcription factor family may allow a deeper understanding of land plant gametophytes.
  • Plant breeding for climate change adaptation

    2009 von Korff, Maria
    Global change threatens agricultural production and represents a challenge for plant breeding research. Consequently, research focuses on elucidating the genetic regulation of adaptation to drought stress in crop plants. Barley is a good model for analysing genetic adaptation mechanisms, as it is characterized by tolerance to abiotic stress and a high genetic diversity. Understanding the genetic regulation of flowering time, for example, will allow the targeted manipulation of development during the breeding process and hence adaptation to changing environments.
  • Chromatin structure and gene control

    2009 Turck, Franziska
    Each cell of higher organisms contains a nucleus where the genetic material is tightly packed. In order to utilize genes, parts of the genetic material need to be unpacked, and protein complexes are involved in the process. Other protein complexes, conversely, function to prevent access to genes disabling gene expression.
  • Making connections: Data integration in biology

    2009 Schoof, Heiko
    Modern molecular biology employs high-throughput methods, for example to determine genome sequences. Their analysis and interpretation increasingly requires integration of heterogeneous data. Standards for access to biological data and web service technologies can facilitate automated finding and invocation of bioinformatics resources.

2008

  • A quest for treasures among wild barleys: How biodiversity in barley is exploited for breeding elite varieties

    2008 Schmalenbach, Inga; Pillen, Klaus
    Cultivated barley ranks number four among the world cereals. Barley emerged about 10000 years ago from wild barley species. At the institute, the genetic diversity among cultivated and wild barley varieties is studied with novel genome research tools. The new results are exploited, on one hand, to support modern plant breeding. On the other hand, the data assist in unravelling the molecular regulation of growth and development in crop plants.
  • Rational design of enzymes with novel catalytic properties

    2008 Kombrink, Erich
    Plants synthesize a vast array of secondary compounds derived from phenylalanine, which fulfill defense functions against unfavorable environmental conditions. To understand the basis for this chemical diversity, the mechanism of substrate selection was unraveled for a key enzyme of phenylpropanoid metabolism. This knowledge may provide strategies of engineering natural product pathways aiming at targeted modifications of plant properties.
  • Are MADS-box genes a key to the understanding of the development and evolution of land plant gametophytes?

    2008 Verelst, Wim; Münster, Thomas
    MIKC* MADS-box proteins constitute a regulatory network controlling important processes in pollen development of Arabidopsis thaliana. Comparative analysis of function, evolution, and systems biology of the MIKC* transcription factor family may allow a deeper understanding of land plant gametophytes.
  • Plant breeding for climate change adaptation

    2008 von Korff, Maria
    Global change threatens agricultural production and represents a challenge for plant breeding research. Consequently, research focuses on elucidating the genetic regulation of adaptation to drought stress in crop plants. Barley is a good model for analysing genetic adaptation mechanisms, as it is characterized by tolerance to abiotic stress and a high genetic diversity. Understanding the genetic regulation of flowering time, for example, will allow the targeted manipulation of development during the breeding process and hence adaptation to changing environments.

2007

  • Activity-based proteomics on plant-pathogen interactions

    2007 Kaschani, Farnusch; Van der Hoorn, Renier
    The activities of enzyme classes in a living organism can be displayed by activity-based profiling. This technology is based on the use of tagged small molecules, which covalently bind to enzymes in an activity-dependent manner. The Plant Chemetics group is developing and applying this technology and other novel chemistry tools to reveal the dynamics of enzyme activities during plant-pathogen interactions.
  • Architecture of flowering plants

    2007 Theres, Klaus
    The architecture of flowering plants shows an enormous heterogeneity. This variability is, to a large extent, caused by the different branching patterns of the vegetative and flowering shoots. Side-shoots originate from secondary meristems, which are formed in the axils of leaves. In tomato and in Arabidopsis, the gene LATERAL SUPPRESSOR (Ls/LAS) encodes a transcription factor controlling the initiation of axillary meristems during vegetative development. The gene is expressed in a narrow domain of the leaf axil and conditions the competence of the meristem founder cells. Transcription factors of the MYB class are also required for axillary meristem formation in specific zones along the shoot axis. Furthermore, plant architecture is strongly influenced by differential outgrowth of the axillary buds. Recently, it has been demonstrated that, in addition to the archetypical plant hormones auxin and cytokinin, bud outgrowth is regulated by a new root derived signal.
  • A quest for treasures among wild barleys: How biodiversity in barley is exploited for breeding elite varieties

    2007 Schmalenbach, Inga; Pillen, Klaus
    Cultivated barley ranks number four among the world cereals. Barley emerged about 10000 years ago from wild barley species. At the institute, the genetic diversity among cultivated and wild barley varieties is studied with novel genome research tools. The new results are exploited, on one hand, to support modern plant breeding. On the other hand, the data assist in unravelling the molecular regulation of growth and development in crop plants.
  • Rational design of enzymes with novel catalytic properties

    2007 Kombrink, Erich
    Plants synthesize a vast array of secondary compounds derived from phenylalanine, which fulfill defense functions against unfavorable environmental conditions. To understand the basis for this chemical diversity, the mechanism of substrate selection was unraveled for a key enzyme of phenylpropanoid metabolism. This knowledge may provide strategies of engineering natural product pathways aiming at targeted modifications of plant properties.

2006

  • A novel function for glutaredoxins in flower development

    2006 Zachgo, Sabine
    The roxy1 mutant from Arabidopsis thaliana initiates a reduced number of petal primordia and exhibits abnormalities during further petal development. The defects are restricted to the second whorl of the flower and independent of the organ identity. ROXY1 is predominantly expressed in tissues that give rise to new flower organs, including petal precursor cells and petal primordia. Glutaredoxins (GRXs) are small, ubiquitous oxidoreductases that have been intensively studied in E. coli, yeast and humans and oxidize or reduce conserved, cysteine containing motifs. They are involved in a large variety of cellular processes and exert a crucial function in the response to oxidative stress. Our data demonstrate that, unexpectedly, a plant glutaredoxin is involved in flower development, likely by mediating posttranslational modifications and thus affecting the activity of target proteins required for normal petal organ initiation and morphogenesis. Surprisingly, ROXY1 belongs to a novel subgroup, the CC-type, being specific for land plants. The existence of large CC-type subfamilies in angiosperms supports the assumption that their capability to posttranslationally modify target protein activity has been integrated into crucial plant specific processes coinciding with the development of complex flowers. Further analysis of ROXY1 and other CC-type members aims for an understanding of their biochemical properties, the identification of target proteins and unraveling the intriguing connection between redox regulation and flower development.
  • Tête-a-tête between plant and fungus: how powdery mildew fungi manipulate their host plants

    2006 Panstruga, Ralph
    Plant mutants that lack the so-called Mlo protein are highly resistant against powdery mildew fungi. It is assumed that the fungus exploits presence of this protein to suppress plant defense mechanisms.
  • Activity-based proteomics on plant-pathogen interactions

    2006 Kaschani, Farnusch; Van der Hoorn, Renier
    The activities of enzyme classes in a living organism can be displayed by activity-based profiling. This technology is based on the use of tagged small molecules, which covalently bind to enzymes in an activity-dependent manner. The Plant Chemetics group is developing and applying this technology and other novel chemistry tools to reveal the dynamics of enzyme activities during plant-pathogen interactions.
  • Architecture of flowering plants

    2006 Theres, Klaus
    The architecture of flowering plants shows an enormous heterogeneity. This variability is, to a large extent, caused by the different branching patterns of the vegetative and flowering shoots. Side-shoots originate from secondary meristems, which are formed in the axils of leaves. In tomato and in Arabidopsis, the gene LATERAL SUPPRESSOR (Ls/LAS) encodes a transcription factor controlling the initiation of axillary meristems during vegetative development. The gene is expressed in a narrow domain of the leaf axil and conditions the competence of the meristem founder cells. Transcription factors of the MYB class are also required for axillary meristem formation in specific zones along the shoot axis. Furthermore, plant architecture is strongly influenced by differential outgrowth of the axillary buds. Recently, it has been demonstrated that, in addition to the archetypical plant hormones auxin and cytokinin, bud outgrowth is regulated by a new root derived signal.

2005

  • Natural variation in higher plants – genes, mechanisms, evolution, plant breeding

    2005 Koornneef, Maarten
    Our long-term goal is the understanding of the genetic differences between Arabidopsis accessions affecting important adaptive traits such as seed dormancy and plant growth. We expect that understanding this genetic variation will help explaining why specific variants are adapted to specific environments and that knowledge of the genetic basis of these traits will help breeding crop plants.
  • Protein Modifiers: Versatile Regulators of Plant Development

    2005 Bachmair, Andreas; Coupland, George
    Protein modifiers are small proteins that can be covalently attached to substrate proteins. The resulting change can influence the function of the substrate protein and can thereby play a role in cellular information transfer. Attachment of modifiers is part of many developmental processes in plants, including flower induction, which depends on an interplay between a genetic program and environmental input parameters for optimal timing and execution.
  • A novel function for glutaredoxins in flower development

    2005 Zachgo, Sabine
    The roxy1 mutant from Arabidopsis thaliana initiates a reduced number of petal primordia and exhibits abnormalities during further petal development. The defects are restricted to the second whorl of the flower and independent of the organ identity. ROXY1 is predominantly expressed in tissues that give rise to new flower organs, including petal precursor cells and petal primordia. Glutaredoxins (GRXs) are small, ubiquitous oxidoreductases that have been intensively studied in E. coli, yeast and humans and oxidize or reduce conserved, cysteine containing motifs. They are involved in a large variety of cellular processes and exert a crucial function in the response to oxidative stress. Our data demonstrate that, unexpectedly, a plant glutaredoxin is involved in flower development, likely by mediating posttranslational modifications and thus affecting the activity of target proteins required for normal petal organ initiation and morphogenesis. Surprisingly, ROXY1 belongs to a novel subgroup, the CC-type, being specific for land plants. The existence of large CC-type subfamilies in angiosperms supports the assumption that their capability to posttranslationally modify target protein activity has been integrated into crucial plant specific processes coinciding with the development of complex flowers. Further analysis of ROXY1 and other CC-type members aims for an understanding of their biochemical properties, the identification of target proteins and unraveling the intriguing connection between redox regulation and flower development.
  • Tête-a-tête between plant and fungus: how powdery mildew fungi manipulate their host plants

    2005 Panstruga, Ralph
    Plant mutants that lack the so-called Mlo protein are highly resistant against powdery mildew fungi. It is assumed that the fungus exploits presence of this protein to suppress plant defense mechanisms.

2004

  • Flowering and Fertility: beyond the MADS-box genes

    2004 Huijser, Peter
    Since their discovery in plants, over a decade ago, the study of MADS-box genes has made a major contribution to our current understanding of flower development at the level of organogenesis. Less well understood, however, remain the molecular genetic mechanisms involved in differentiation at the cellular level within these floral organs. In particular, how the cell lineages giving rise to the sex cells, in a process known as sporogenesis, become specified within the anthers and ovules is not well understood. As an unexpected outcome of our research on MADS-box genes, we uncovered a novel and plant specific family of transcription factors and found one of its members to control the process of sporogenesis. Its future analysis may contribute to a better understanding of sexual reproduction of plants.
  • Molecular diagnosis of complex traits in crop plants.

    2004 Gebhardt, Christiane
    Genetic variability and environmental factors determine the phenotype of the individuals of the same species. The possibilities to identify genetic variability at the DNA level, the availability of partial or even complete DNA sequence information of a multitude of organisms and the knowledge of gene function make it possible to explore the molecular basis of complex traits of humans, animals or plants. Knowledge on the molecular basis of complex traits of crop plants can contribute to the efficient selection of new varieties that are better adapted to human needs. In a pilot experiment, an association was found between field resistance of potato varieties to the late blight disease and DNA variants in a particular segment of the genome of potato (Solanum tuberosum).Christiane Gebhardt
  • Natural variation in higher plants – genes, mechanisms, evolution, plant breeding

    2004 Koornneef, Maarten
    Our long-term goal is the understanding of the genetic differences between Arabidopsis accessions affecting important adaptive traits such as seed dormancy and plant growth. We expect that understanding this genetic variation will help explaining why specific variants are adapted to specific environments and that knowledge of the genetic basis of these traits will help breeding crop plants.
  • Protein Modifiers: Versatile Regulators of Plant Development

    2004 Bachmair, Andreas; Coupland, George
    Protein modifiers are small proteins that can be covalently attached to substrate proteins. The resulting change can influence the function of the substrate protein and can thereby play a role in cellular information transfer. Attachment of modifiers is part of many developmental processes in plants, including flower induction, which depends on an interplay between a genetic program and environmental input parameters for optimal timing and execution.

2003

  • Flowering and Fertility: beyond the MADS-box genes

    2003 Huijser, Peter
    Since their discovery in plants, over a decade ago, the study of MADS-box genes has made a major contribution to our current understanding of flower development at the level of organogenesis. Less well understood, however, remain the molecular genetic mechanisms involved in differentiation at the cellular level within these floral organs. In particular, how the cell lineages giving rise to the sex cells, in a process known as sporogenesis, become specified within the anthers and ovules is not well understood. As an unexpected outcome of our research on MADS-box genes, we uncovered a novel and plant specific family of transcription factors and found one of its members to control the process of sporogenesis. Its future analysis may contribute to a better understanding of sexual reproduction of plants.
  • Molecular diagnosis of complex traits in crop plants.

    2003 Gebhardt, Christiane
    Genetic variability and environmental factors determine the phenotype of the individuals of the same species. The possibilities to identify genetic variability at the DNA level, the availability of partial or even complete DNA sequence information of a multitude of organisms and the knowledge of gene function make it possible to explore the molecular basis of complex traits of humans, animals or plants. Knowledge on the molecular basis of complex traits of crop plants can contribute to the efficient selection of new varieties that are better adapted to human needs. In a pilot experiment, an association was found between field resistance of potato varieties to the late blight disease and DNA variants in a particular segment of the genome of potato (Solanum tuberosum).Christiane Gebhardt
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