Institute of Plant Biology

Szeged, Hungary

Institute of Plant Biology

Szeged, Hungary

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Boyko A.,Institute of Plant Biology | Kovalchuk I.,University of Lethbridge
Molecular Plant | Year: 2011

Recent reports suggest that exposure to stress is capable of influencing the frequency and pattern of inherited changes in various parts of the genome. In this review, we will discuss the influence of viral pathogens on somatic and meiotic genome stability of Nicotiana tabacum and Arabidopsis thaliana. Plants infected with a compatible pathogen generate a systemic recombination signal that precedes the spread of pathogens and results in changes in the somatic and meiotic recombination frequency. The progeny of infected plants exhibit changes in global and locus-specific DNA methylation patterns, genomic rearrangements at transgenic reporter loci and resistance gene-like-loci, and even tolerance to pathogen infection and abiotic stress. Here, we will discuss the contribution of environmental stresses to genome evolution and will focus on the role of heritable epigenetic changes in response to pathogen infection. © The Author 2011. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.


Boyko A.,Institute of Plant Biology | Kovalchuk I.,University of Lethbridge
Current Opinion in Plant Biology | Year: 2011

As sessile organisms, plants need to continuously adjust their responses to external stimuli to cope with changing growth conditions. Since the seed dispersal range is often rather limited, exposure of progeny to the growth conditions of parents is very probable. The plasticity of plant phenotypes cannot be simply explained by genetic changes such as point mutations, deletions, insertions and gross chromosomal rearrangements. Since many environmental stresses persist for only one or several plant generations, other mechanisms of adaptation must exist. The heritability of reversible epigenetic modifications that regulate gene expression without changing DNA sequence makes them an attractive alternative mechanism. In this review, we discuss recent advances in understanding how changes in genome stability and epigenetically mediated changes in gene expression could contribute to plant adaptation. We provide examples of environmentally induced transgenerational epigenetic effects that include the appearance of new phenotypes in successive generations of stressed plants. We also describe several cases in which exposure to stress leads to nonrandom heritable but reversible changes in stress tolerance in the progeny of stressed plants. © 2011 Elsevier Ltd.


Szabados L.,Institute of Plant Biology | Savoure A.,University Pierre and Marie Curie
Trends in Plant Science | Year: 2010

Proline accumulates in many plant species in response to environmental stress. Although much is now known about proline metabolism, some aspects of its biological functions are still unclear. Here, we discuss the compartmentalization of proline biosynthesis, accumulation and degradation in the cytosol, chloroplast and mitochondria. We also describe the role of proline in cellular homeostasis, including redox balance and energy status. Proline can act as a signaling molecule to modulate mitochondrial functions, influence cell proliferation or cell death and trigger specific gene expression, which can be essential for plant recovery from stress. Although the regulation and function of proline accumulation are not yet completely understood, the engineering of proline metabolism could lead to new opportunities to improve plant tolerance of environmental stresses. © 2009 Elsevier Ltd. All rights reserved.


News Article | January 12, 2016
Site: phys.org

Researchers collected samples from infected grain fields all over Europe. Credit: UZH For the past few years, mildew has been able to infect triticale grain, which up to then had been resistant to this fungal disease. So how was the pathogen able to spread to a different host plant? Researchers from the University of Zurich have shown that the new pathogen is a genetic mix of existing mildew forms. Triticale is an artificial grain type stemming from a cross between wheat and rye. Since the 1960s, triticale has been cultivated in many places as a feed grain and had proved very resistant to mildew attack. This fungal pathogen causes huge losses in cereal production. In the case of wheat, for example, the fungus can reduce the harvest by up to 45%. But triticale fields were infected for the first time in 2001, and mildew is now being reported in many triticale growing regions in Europe. Comparison of the mildew genome confirms: The new form is a hybrid Researchers from the University of Zurich have now examined how the mildew managed to spread to triticale. To do this, they collected samples from infected grain fields all over Europe and examined the genetic information of different forms of mildew. The genetic material (genome) of the pathogens that attack triticale, rye and wheat were then compared using bioinformatics. The comparisons showed that the new triticale fungus is a hybrid of the variants specialized in wheat and rye: 12.5% of the genome is identical to DNA sequences from the form specialized in rye, while 87.5% stems from the form specialized in wheat. Evolution of the pathogen reflects the development of the host plant This means that a hybrid from two mildew variants specialized in two different host plants can infect the cross between those two host plants. The study thus shows the manner in which mildew adapts to new host plants in a co-evolutionary way and can break down their resistance. The study also reveals that this recent evolutionary event was not a one-off occurrence. Around 10,000 years ago, mildew overcame the resistance of bread wheat, which was relatively new at the time, in the same way. "These results are of major significance for treating and preventing plant diseases. The more we know about the evolutionary mechanisms of mildew, the better we can keep new cultivated plants resistant to the pathogens", explains Thomas Wicker from the Institute of Plant Biology at the University of Zurich. Explore further: Powdery mildew at an evolutionary dead end More information: Fabrizio Menardo et al. Hybridization of powdery mildew strains gives rise to pathogens on novel agricultural crop species, Nature Genetics (2016). DOI: 10.1038/ng.3485


Song Z.-T.,Institute of Plant Biology | Sun L.,Institute of Plant Biology | Lu S.-J.,Institute of Plant Biology | Tian Y.,Hefei University of Technology | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Accumulation of unfolded or misfolded proteins causes endoplasmic reticulum (ER) stress, which activates a set of ER membraneassociated transcription factors for protein homeostasis regulation. Previous genome-wide chromatin immunoprecipitation analysis shows a strong correlation between histone H3K4 trimethylation (H3K4me3) and active gene expression. However, how the histone modification complex is specifically and timely recruited to the active promoters remains unknown. Using ER stress responsive gene expression as a model system, we demonstrate that sequencespecific transcription factors interact with COMPASS-like components and affect H3K4me3 formation at specific target sites in Arabidopsis. Gene profiling analysis reveals that membrane-associated basic leucine zipper (bZIP) transcription factors bZIP28 and bZIP60 regulate most of the ER stress responsive genes. Loss-offunctions of bZIP28 and bZIP60 impair the occupancy of H3K4me3 on promoter regions of ER stress responsive genes. Further, in vitro pull-down assays and in vivo bimolecular fluorescence complementation (BiFC) experiments show that bZIP28 and bZIP60 interact with Ash2 and WDR5a, both of which are core COMPASS-like components. Knockdown expression of either Ash2 or WDR5a decreased the expression of several ER stress responsive genes. The COMPASSlike complex is known to interact with histone methyltransferase to facilitate preinitiation complex (PIC) assembly and generate H3K4me3 during transcription elongation. Thus, our data shows that the ER stress stimulus causes the formation of PIC and deposition of H3K4me3 mark at specific promoters through the interaction between transcription factor and COMPASS-like components.


Papdi C.,Institute of Plant Biology
Methods in molecular biology (Clifton, N.J.) | Year: 2010

A powerful means to learn about gene functions in a developmental or physiological context in an organism is to isolate the corresponding mutants with altered phenotypes. Diverse mutagenic agents, including chemical and biological, have been widely employed, and each comes with its own advantages and inconveniences. For Arabidopsis thaliana, whose genome sequence is publicly available, the reliance of reverse genetics to understand the relevant roles of genes particularly those coding for proteins in growth and development is now a common practice. Identifying multiple alleles at each locus is important because they can potentially reveal epistatic relationship in a signaling pathway or components belonging to a common signaling complex by their synergistic or even allele-specific enhancement of the phenotypic severity. In this article, we describe mutagenesis by using ethyl methanesulfonate (EMS) and transfer (T)-DNA-mediated insertion or activation tagging as applied to the most widely used genetic plant model A. thaliana. Also, we demonstrate the utility of several genetic screening approaches to dissect adaptive responses to various abiotic stresses.


Abraham E.,Institute of Plant Biology
Methods in molecular biology (Clifton, N.J.) | Year: 2010

Accumulation of proline in higher plants is an indication of disturbed physiological condition, triggered by biotic or abiotic stress condition. Free proline content can increase upon exposure of plants to drought, salinity, cold, heavy metals, or certain pathogens. Determination of free proline levels is a useful assay to monitor physiological status and to assess stress tolerance of higher plants. Here we describe three methods suitable for determination of free proline content. The isatin paper assay is simple and is suitable to assay proline content in large number of samples. The colorimetric measurement is quantitative and provides reliable data about proline content. The HPLC-based amino acid analysis can be employed when concentration of all amino acids has to be compared.


Vass I.,Institute of Plant Biology
Biochimica et Biophysica Acta - Bioenergetics | Year: 2012

Light induced damage of the photosynthetic apparatus is an important and highly complex phenomenon, which affects primarily the Photosystem II complex. Here the author summarizes the current state of understanding of the molecular mechanisms, which are involved in the light induced inactivation of Photosystem II electron transport together with the relevant mechanisms of photoprotection. Short wavelength ultraviolet radiation impairs primarily the Mn 4Ca catalytic site of the water oxidizing complex with additional effects on the quinone electron acceptors and tyrosine donors of PSII. The main mechanism of photodamage by visible light appears to be mediated by acceptor side modifications, which develop under conditions of excess excitation in which the capacity of light-independent photosynthetic processes limits the utilization of electrons produced in the initial photoreactions. This situation of excess excitation facilitates the reduction of intersystem electron carriers and Photosystem II acceptors, and thereby induces the formation of reactive oxygen species, especially singlet oxygen whose production is sensitized by triplet chlorophyll formation in the reaction center of Photosystem II. The highly reactive singlet oxygen and other reactive oxygen species, such as H 2O 2 and O 2 -, which can also be formed in Photosystem II initiate damage of electron transport components and protein structure. In parallel with the excess excitation dependent mechanism of photodamage inactivation of the Mn 4Ca cluster by visible light may also occur, which impairs electron transfer through the Photosystem II complex and initiates further functional and structural damage of the reaction center via formation of highly oxidizing radicals, such as P680 + and Tyr-Z +. However, the available data do not support the hypothesis that the Mn-dependent mechanism would be the exclusive or dominating pathway of photodamage in the visible spectral range. This article is part of a Special Issue entitled: Photosystem II. © 2011 Elsevier B.V. All rights reserved.


Vass I.,Institute of Plant Biology
Physiologia Plantarum | Year: 2011

Light-induced damage of the photosynthetic apparatus is an important and complex phenomenon, which affects primarily the photosystem II (PSII) complex. Here, the author summarizes the current state of understanding, which concerns the role of charge recombination reactions in photodamage and photoprotection. The main mechanism of photodamage induced by visible light appears to be mediated by acceptor side modifications, which develop under light intensity conditions when the capacity of light-independent photosynthetic processes limits the utilization of electrons produced in the initial photoreactions. This situation facilitates triplet chlorophyll formation and singlet oxygen production in the reaction center of PSII, which initiates the damage of electron transport components and protein structure. This mechanism is an important, but not exclusive, pathway of photodamage, and light-induced inactivation of the Mn cluster of water oxidation may occur in parallel with the singlet oxygen-dependent pathway. © Physiologia Plantarum 2011.


News Article | January 12, 2016
Site: www.rdmag.com

​Triticale is an artificial grain type stemming from a cross between wheat and rye. Since the 1960s, triticale has been cultivated in many places as a feed grain and had proved very resistant to mildew attack. This fungal pathogen causes huge losses in cereal production. In the case of wheat, for example, the fungus can reduce the harvest by up to 45%. But triticale fields were infected for the first time in 2001, and mildew is now being reported in many triticale growing regions in Europe. Comparison of the mildew genome confirms: The new form is a hybrid Researchers from the University of Zurich have now examined how the mildew managed to spread to triticale. To do this, they collected samples from infected grain fields all over Europe and examined the genetic information of different forms of mildew. The genetic material (genome) of the pathogens that attack triticale, rye and wheat were then compared using bioinformatics. The comparisons showed that the new triticale fungus is a hybrid of the variants specialized in wheat and rye: 12.5% of the genome is identical to DNA sequences from the form specialized in rye, while 87.5% stems from the form specialized in wheat. Evolution of the pathogen reflects the development of the host plant This means that a hybrid from two mildew variants specialized in two different host plants can infect the cross between those two host plants. The study thus shows the manner in which mildew adapts to new host plants in a co-evolutionary way and can break down their resistance. The study also reveals that this recent evolutionary event was not a one-off occurrence. Around 10,000 years ago, mildew overcame the resistance of bread wheat, which was relatively new at the time, in the same way. "These results are of major significance for treating and preventing plant diseases. The more we know about the evolutionary mechanisms of mildew, the better we can keep new cultivated plants resistant to the pathogens", explains Thomas Wicker from the Institute of Plant Biology at the University of Zurich.

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