@article{ShirzadianKhorramabadJingEvertsetal.2010, author = {Shirzadian-Khorramabad, Reza and Jing, Hai-Chun and Everts, Gerja E. and Schippers, Jos H. M. and Hille, Jacques and Dijkwel, Paul P.}, title = {A mutation in the cytosolic O-acetylserine (thiol) lyase induces a genome-dependent early leaf death phenotype in Arabidopsis}, issn = {1471-2229}, doi = {10.1186/1471-2229-10-80}, year = {2010}, abstract = {Background: Cysteine is a component in organic compounds including glutathione that have been implicated in the adaptation of plants to stresses. O-acetylserine (thiol) lyase (OAS-TL) catalyses the final step of cysteine biosynthesis. OAS-TL enzyme isoforms are localised in the cytoplasm, the plastids and mitochondria but the contribution of individual OAS-TL isoforms to plant sulphur metabolism has not yet been fully clarified. Results: The seedling lethal phenotype of the Arabidopsis onset of leaf death3-1 (old3-1) mutant is due to a point mutation in the OAS-A1 gene, encoding the cytosolic OAS-TL. The mutation causes a single amino acid substitution from Gly(162) to Glu(162), abolishing old3-1 OAS-TL activity in vitro. The old3-1 mutation segregates as a monogenic semidominant trait when backcrossed to its wild type accession Landsberg erecta (Ler-0) and the Di-2 accession. Consistent with its semi- dominant behaviour, wild type Ler-0 plants transformed with the mutated old3-1 gene, displayed the early leaf death phenotype. However, the old3-1 mutation segregates in an 11: 4: 1 (wild type: semi-dominant: mutant) ratio when backcrossed to the Colombia-0 and Wassilewskija accessions. Thus, the early leaf death phenotype depends on two semi- dominant loci. The second locus that determines the old3-1 early leaf death phenotype is referred to as odd-ler (for old3 determinant in the Ler accession) and is located on chromosome 3. The early leaf death phenotype is temperature dependent and is associated with increased expression of defence-response and oxidative-stress marker genes. Independent of the presence of the odd-ler gene, OAS-A1 is involved in maintaining sulphur and thiol levels and is required for resistance against cadmium stress. Conclusions: The cytosolic OAS-TL is involved in maintaining organic sulphur levels. The old3-1 mutation causes genome-dependent and independent phenotypes and uncovers a novel function for the mutated OAS- TL in cell death regulation.}, language = {en} } @article{ZhaoXiaWuetal.2018, author = {Zhao, Liming and Xia, Yan and Wu, Xiao-Yuan and Schippers, Jos H. M. and Jing, Hai-Chun}, title = {Phenotypic analysis and molecular markers of leaf senescence}, series = {Plant Senescence: Methods and Protocols}, volume = {1744}, journal = {Plant Senescence: Methods and Protocols}, publisher = {Humana Press Inc.}, address = {Totowa}, isbn = {978-1-4939-7672-0}, issn = {1064-3745}, doi = {10.1007/978-1-4939-7672-0_3}, pages = {35 -- 48}, year = {2018}, abstract = {The process of leaf senescence consists of the final stage of leaf development. It has evolved as a mechanism to degrade macromolecules and micronutrients and remobilize them to other developing parts of the plant; hence it plays a central role for the survival of plants and crop production. During senescence, a range of physiological, morphological, cellular, and molecular events occur, which are generally referred to as the senescence syndrome that includes several hallmarks such as visible yellowing, loss of chlorophyll and water content, increase of ion leakage and cell death, deformation of chloroplast and cell structure, as well as the upregulation of thousands of so-called senescence-associated genes (SAGs) and downregulation of photosynthesis-associated genes (PAGs). This chapter is devoted to methods characterizing the onset and progression of leaf senescence at the morphological, physiological, cellular, and molecular levels. Leaf senescence normally progresses in an age-dependent manner but is also induced prematurely by a variety of environmental stresses in plants. Focused on the hallmarks of the senescence syndrome, a series of protocols is described to asses quantitatively the senescence process caused by developmental cues or environmental perturbations. We first briefly describe the senescence process, the events associated with the senescence syndrome, and the theories and methods to phenotype senescence. Detailed protocols for monitoring senescence in planta and in vitro, using the whole plant and the detached leaf, respectively, are presented. For convenience, most of the protocols use the model plant species Arabidopsis and rice, but they can be easily extended to other plants.}, language = {en} } @misc{ShirzadianKhorramabadJingEvertsetal.2010, author = {Shirzadian-Khorramabad, Reza and Jing, Hai-Chun and Everts, Gerja E. and Schippers, Jos H. M. and Hille, Jacques and Dijkwel, Paul P.}, title = {A mutation in the cytosolic O-acetylserine (thiol) lyase induces a genome-dependent early leaf death phenotype in Arabidopsis}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {833}, issn = {1866-8372}, doi = {10.25932/publishup-42757}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427574}, pages = {14}, year = {2010}, abstract = {Background: Cysteine is a component in organic compounds including glutathione that have been implicated in the adaptation of plants to stresses. O-acetylserine (thiol) lyase (OAS-TL) catalyses the final step of cysteine biosynthesis. OAS-TL enzyme isoforms are localised in the cytoplasm, the plastids and mitochondria but the contribution of individual OAS-TL isoforms to plant sulphur metabolism has not yet been fully clarified. Results: The seedling lethal phenotype of the Arabidopsis onset of leaf death3-1 (old3-1) mutant is due to a point mutation in the OAS-A1 gene, encoding the cytosolic OAS-TL. The mutation causes a single amino acid substitution from Gly(162) to Glu(162), abolishing old3-1 OAS-TL activity in vitro. The old3-1 mutation segregates as a monogenic semidominant trait when backcrossed to its wild type accession Landsberg erecta (Ler-0) and the Di-2 accession. Consistent with its semi-dominant behaviour, wild type Ler-0 plants transformed with the mutated old3-1 gene, displayed the early leaf death phenotype. However, the old3-1 mutation segregates in an 11: 4: 1 (wild type: semi-dominant: mutant) ratio when backcrossed to the Colombia-0 and Wassilewskija accessions. Thus, the early leaf death phenotype depends on two semi-dominant loci. The second locus that determines the old3-1 early leaf death phenotype is referred to as odd-ler (for old3 determinant in the Ler accession) and is located on chromosome 3. The early leaf death phenotype is temperature dependent and is associated with increased expression of defence-response and oxidative-stress marker genes. Independent of the presence of the odd-ler gene, OAS-A1 is involved in maintaining sulphur and thiol levels and is required for resistance against cadmium stress. Conclusions: The cytosolic OAS-TL is involved in maintaining organic sulphur levels. The old3-1 mutation causes genome-dependent and independent phenotypes and uncovers a novel function for the mutated OAS-TL in cell death regulation.}, language = {en} } @misc{VogtSchippers2015, author = {Vogt, Julia H. M. and Schippers, Jos H. M.}, title = {Setting the PAS, the role of circadian PAS domain proteins during environmental adaptation in plants}, series = {Frontiers in plant science}, volume = {6}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2015.00513}, pages = {10}, year = {2015}, abstract = {The per-ARNT-sim (PAS) domain represents an ancient protein module that can be found across all kingdoms of life. The domain functions as a sensing unit for a diverse array of signals, including molecular oxygen, small metabolites, and light. In plants, several PAS domain-containing proteins form an integral part of the circadian clock and regulate responses to environmental change. Moreover, these proteins function in pathways that control development and plant stress adaptation responses. Here, we discuss the role of PAS domain-containing proteins in anticipation, and adaptation to environmental changes in plants.}, language = {en} } @misc{VogtSchippers2015, author = {Vogt, Julia H. M. and Schippers, Jos H. M.}, title = {Setting the PAS, the role of circadian PAS domain proteins during environmental adaptation in plants}, series = {Frontiers in plant science}, journal = {Frontiers in plant science}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406492}, pages = {10}, year = {2015}, abstract = {The per-ARNT-sim (PAS) domain represents an ancient protein module that can be found across all kingdoms of life. The domain functions as a sensing unit for a diverse array of signals, including molecular oxygen, small metabolites, and light. In plants, several PAS domain-containing proteins form an integral part of the circadian clock and regulate responses to environmental change. Moreover, these proteins function in pathways that control development and plant stress adaptation responses. Here, we discuss the role of PAS domain-containing proteins in anticipation, and adaptation to environmental changes in plants.}, language = {en} } @article{LaiDentonGilesMuellerRoeberetal.2011, author = {Lai, Alvina G. and Denton-Giles, Matthew and M{\"u}ller-R{\"o}ber, Bernd and Schippers, Jos H. M. and Dijkwel, Paul P.}, title = {Positional information resolves structural variations and uncovers an evolutionarily divergent genetic locus in accessions of arabidopsis thaliana}, series = {Genome biology and evolution}, volume = {3}, journal = {Genome biology and evolution}, number = {1-2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1759-6653}, doi = {10.1093/gbe/evr038}, pages = {627 -- 640}, year = {2011}, abstract = {Genome sequencing of closely related individuals has yielded valuable insights that link genome evolution to phenotypic variations. However, advancement in sequencing technology has also led to an escalation in the number of poor quality-drafted genomes assembled based on reference genomes that can have highly divergent or haplotypic regions. The self-fertilizing nature of Arabidopsis thaliana poses an advantage to sequencing projects because its genome is mostly homozygous. To determine the accuracy of an Arabidopsis drafted genome in less conserved regions, we performed a resequencing experiment on a similar to 371-kb genomic interval in the Landsberg erecta (Ler-0) accession. We identified novel structural variations (SVs) between Ler-0 and the reference accession Col-0 using a long-range polymerase chain reaction approach to generate an Illumina data set that has positional information, that is, a data set with reads that map to a known location. Positional information is important for accurate genome assembly and the resolution of SVs particularly in highly duplicated or repetitive regions. Sixty-one regions with misassembly signatures were identified from the Ler-0 draft, suggesting the presence of novel SVs that are not represented in the draft sequence. Sixty of those were resolved by iterative mapping using our data set. Fifteen large indels (> 100 bp) identified from this study were found to be located either within protein-coding regions or upstream regulatory regions, suggesting the formation of novel alleles or altered regulation of existing genes in Ler-0. We propose future genome-sequencing experiments to follow a clone-based approach that incorporates positional information to ultimately reveal haplotype-specific differences between accessions.}, language = {en} } @article{LaiDohertyMuellerRoeberetal.2012, author = {Lai, Alvina Grace and Doherty, Colleen J. and M{\"u}ller-R{\"o}ber, Bernd and Kay, Steve A. and Schippers, Jos H. M. and Dijkwel, Paul P.}, title = {CIRCADIAN CLOCK-ASSOCIATED 1 regulates ROS homeostasis and oxidative stress responses}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {109}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {42}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1209148109}, pages = {17129 -- 17134}, year = {2012}, abstract = {Organisms have evolved endogenous biological clocks as internal timekeepers to coordinate metabolic processes with the external environment. Here, we seek to understand the mechanism of synchrony between the oscillator and products of metabolism known as Reactive Oxygen Species (ROS) in Arabidopsis thaliana. ROS-responsive genes exhibit a time-of-day-specific phase of expression under diurnal and circadian conditions, implying a role of the circadian clock in transcriptional regulation of these genes. Hydrogen peroxide production and scavenging also display time-of-day phases. Mutations in the core-clock regulator, CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), affect the transcriptional regulation of ROS-responsive genes, ROS homeostasis, and tolerance to oxidative stress. Mis-expression of EARLY FLOWERING 3, LUX ARRHYTHMO, and TIMING OF CAB EXPRESSION 1 affect ROS production and transcription, indicating a global effect of the clock on the ROS network. We propose CCA1 as a master regulator of ROS homeostasis through association with the Evening Element in promoters of ROS genes in vivo to coordinate time-dependent responses to oxidative stress. We also find that ROS functions as an input signal that affects the transcriptional output of the clock, revealing an important link between ROS signaling and circadian output. Temporal coordination of ROS signaling by CCA1 and the reciprocal control of circadian output by ROS reveal a mechanistic link that allows plants to master oxidative stress responses.}, language = {en} } @misc{SchippersNguyenLuetal.2012, author = {Schippers, Jos H. M. and Nguyen, Hung M. and Lu, Dandan and Schmidt, Romy and M{\"u}ller-R{\"o}ber, Bernd}, title = {ROS homeostasis during development: an evolutionary conserved strategy}, series = {Cellular and molecular life sciences}, volume = {69}, journal = {Cellular and molecular life sciences}, number = {19}, publisher = {Springer}, address = {Basel}, issn = {1420-682X}, doi = {10.1007/s00018-012-1092-4}, pages = {3245 -- 3257}, year = {2012}, abstract = {The balance between cellular proliferation and differentiation is a key aspect of development in multicellular organisms. Recent studies on Arabidopsis roots revealed distinct roles for different reactive oxygen species (ROS) in these processes. Modulation of the balance between ROS in proliferating cells and elongating cells is controlled at least in part at the transcriptional level. The effect of ROS on proliferation and differentiation is not specific for plants but appears to be conserved between prokaryotic and eukaryotic life forms. The ways in which ROS is received and how it affects cellular functioning is discussed from an evolutionary point of view. The different redox-sensing mechanisms that evolved ultimately result in the activation of gene regulatory networks that control cellular fate and decision-making. This review highlights the potential common origin of ROS sensing, indicating that organisms evolved similar strategies for utilizing ROS during development, and discusses ROS as an ancient universal developmental regulator.}, language = {en} } @article{PetrovSchippersBeninaetal.2013, author = {Petrov, Veselin and Schippers, Jos and Benina, Maria and Minkov, Ivan and M{\"u}ller-R{\"o}ber, Bernd and Gechev, Tsanko S.}, title = {In search for new players of the oxidative stress network by phenotyping an Arabidopsis T-DNA mutant collection on reactive oxygen species-eliciting chemicals}, series = {Plant omics}, volume = {6}, journal = {Plant omics}, number = {1}, publisher = {Southern Cross Publ.}, address = {Lismore}, issn = {1836-0661}, pages = {46 -- 54}, year = {2013}, abstract = {The ability of some chemical compounds to cause oxidative stress offers a fast and convenient way to study the responses of plants to reactive oxygen species (ROS). In order to unveil potential novel genetic players of the ROS-regulatory network, a population of similar to 2,000 randomly selected Arabidopsis thaliana T-DNA insertion mutants was screened for ROS sensitivity/resistance by growing seedlings on agar medium supplemented with stress-inducing concentrations of the superoxide-eliciting herbicide methyl viologen or the catalase inhibitor 3-amino-triazole. A semi-robotic setup was used to capture and analyze images of the chemically treated seedlings which helped interpret the screening results by providing quantitative information on seedling area and healthy-to-chlorotic tissue ratios for data verification. A ROS-related phenotype was confirmed in three of the initially selected 33 mutant candidates, which carry T-DNA insertions in genes encoding a Ring/Ubox superfamily protein, ABI5 binding protein 1 (AFP1), previously reported to be involved in ABA signaling, and a protein of unknown function, respectively. In addition, we identified six mutants, most of which have not been described yet, that are related to growth or chloroplast development and show defects in a ROS-independent manner. Thus, semi-automated image capturing and phenotyping applied on publically available T-DNA insertion collections adds a simple means for discovering novel mutants in complex physiological processes and identifying the genes involved.}, language = {en} } @article{SchmidtSchippersWelkeretal.2012, author = {Schmidt, Romy and Schippers, Jos H. M. and Welker, Annelie and Mieulet, Delphine and Guiderdoni, Emmanuel and M{\"u}ller-R{\"o}ber, Bernd}, title = {Transcription factor OsHsfC1b regulates salt tolerance and development in Oryza sativa ssp japonica}, series = {AoB PLANTS}, journal = {AoB PLANTS}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {2041-2851}, doi = {10.1093/aobpla/pls011}, pages = {17}, year = {2012}, abstract = {Background and aims Salt stress leads to attenuated growth and productivity in rice. Transcription factors like heat shock factors (HSFs) represent central regulators of stress adaptation. Heat shock factors of the classes A and B are well established as regulators of thermal and non-thermal stress responses in plants; however, the role of class C HSFs is unknown. Here we characterized the function of the OsHsfC1b (Os01g53220) transcription factor from rice. Methodology We analysed the expression of OsHsfC1b in the rice japonica cultivars Dongjin and Nipponbare exposed to salt stress as well as after mannitol, abscisic acid (ABA) and H2O2 treatment. For functional characterization of OsHsfC1b, we analysed the physiological response of a T-DNA insertion line (hsfc1b) and two artificial micro-RNA (amiRNA) knock-down lines to salt, mannitol and ABA treatment. In addition, we quantified the expression of small Heat Shock Protein (sHSP) genes and those related to signalling and ion homeostasis by quantitative real-time polymerase chain reaction in roots exposed to salt. The subcellular localization of OsHsfC1b protein fused to green fluorescent protein (GFP) was determined in Arabidopsis mesophyll cell protoplasts. Principal results Expression of OsHsfC1b was induced by salt, mannitol and ABA, but not by H2O2. Impaired function of OsHsfC1b in the hsfc1b mutant and the amiRNA lines led to decreased salt and osmotic stress tolerance, increased sensitivity to ABA, and temporal misregulation of salt-responsive genes involved in signalling and ion homeostasis. Furthermore, sHSP genes showed enhanced expression in knock-down plants under salt stress. We observed retarded growth of hsfc1b and knock-down lines in comparison with control plants under non-stress conditions. Transient expression of OsHsfC1b fused to GFP in protoplasts revealed nuclear localization of the transcription factor. Conclusions OsHsfC1b plays a role in ABA-mediated salt stress tolerance in rice. Furthermore, OsHsfC1b is involved in the response to osmotic stress and is required for plant growth under non-stress conditions.}, language = {en} }