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Publikationen - Molekulare Signalverarbeitung

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Publikation

Wasternack, C.; Hause, B. Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in <span>Annals of Botany</span> Annals of Botany 111, 1021-1058, (2013) DOI: 10.1093/aob/mct067

Background: Jasmonates are important regulators in plant responses to biotic and abiotic stresses as well as indevelopment. Synthesized from lipid-constituents, the initially formed jasmonic acid is converted to differentmetabolites including the conjugate with isoleucine. Important new components of jasmonate signalling includingits receptor were identified, providing deeper insight into the role of jasmonate signalling pathways in stressresponses and development.Scope: The present review is an update of the review on jasmonates published in this journal in 2007. New dataof the last five years are described with emphasis on metabolites of jasmonates, on jasmonate perception andsignalling, on cross-talk to other plant hormones and on jasmonate signalling in response to herbivores and pathogens,in symbiotic interactions, in flower development, in root growth and in light perception.Conclusions: The last few years have seen breakthroughs in the identification of JASMONATE ZIM DOMAIN(JAZ) proteins and their interactors such as transcription factors and co-repressors, and the crystallization of thejasmonate receptor as well as of the enzyme conjugating jasmonate to amino acids. Now, the complex nature ofnetworks of jasmonate signalling in stress responses and development including hormone cross-talk can beaddressed.
Publikation

Elleuch, A.; Chaâbene, Z.; Grubb, D.C.; Drira, N.; Mejdoub, H.; Khemakhem, B. Morphological and biochemical behavior of fenugreek (Trigonella foenum-graecum) under copper stress Ecotoxicol Environ Saf 98, 46-53, (2013) DOI: 10.1016/j.ecoenv.2013.09.028

The effects of copper on germination and growth of fenugreek (Trigonella foenum-graecum  ) was investigated separately using different concentrations of CuSO4. The germination percentage and radical length had different responses to cupric ions: the root growth increased with increasing copper concentration up to 1 mM Cu+2Cu2+ and was inhibited thereafter. In contrast, the germination percentage was largely unaffected by concentrations of copper below 10 mM.The reduction in root growth may have been due to inhibition of hydrolytic enzymes such as amylase. Indeed, the average total amylolytic activity decreased from the first day of treatment with [Cu+2Cu2+] greater than 1 mM. Furthermore, copper affected various plant growth parameters. Copper accumulation was markedly higher in roots as compared to shoots. While both showed a gradual decrease in growth, this was more pronounced in roots than in leaves and in stems. Excess copper induced an increase in the rate of hydrogen peroxide (H2O2) production and lipid peroxidation in all plant parts, indicating oxidative stress. This redox stress affected leaf chlorophyll and carotenoid content which decreased in response to augmented Cu levels. Additionally, the activities of proteins involved in reactive oxygen species (ROS) detoxification were affected. Cu stress elevated the ascorbate peroxidase (APX) activity more than two times at 10 mM CuSO4. In contrast, superoxide dismutase (SOD) and catalase (CAT) levels showed only minor variations, only at 1 mM Cu+2Cu2+. Likewise, total phenol and flavonoid contents were strongly induced by low concentrations of copper, consistent with the role of these potent antioxidants in scavenging ROS such as H2O2, but returned to control levels or below at high [Cu+2Cu2+]. Taken together, these results indicate a fundamental shift in the plant response to copper toxicity at low versus high concentrations.
Publikation

Wasternack, C.; Stenzel, I.; Hause, B.; Hause, G.; Kutter, C.; Maucher, H.; Neumerkel, J.; Feussner, I.; Miersch, O. The wound response in tomato - Role of jasmonic acid J. Plant Physiol 163, 297-306 , (2006) DOI: 10.1016/j.jplph.2005.10.014

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Publikation

Abel, S.; Savchenko, T.; Levy, M. Genome-wide comparative analysis of the <em>IQD</em> gene families in <em>Arabidopsis thaliana</em> and Oryza sativa BMC Evolutionary Biology 5, 72 (1-25), (2005)

We identified and analyzed 33 and 29 IQD1-like genes in Arabidopsis thaliana and Oryza sativa, respectively. The encoded IQD proteins contain a plant-specific domain of 67 conserved amino acid residues, referred to as the IQ67 domain, which is characterized by a unique and repetitive arrangement of three different calmodulin recruitment motifs, known as the IQ, 1-5-10, and 1-8-14 motifs. We demonstrated calmodulin binding for IQD20, the smallest IQD protein in Arabidopsis, which consists of a C-terminal IQ67 domain and a short N-terminal extension. A striking feature of IQD proteins is the high isoelectric point (~10.3) and frequency of serine residues (~11%). We compared the Arabidopsis and rice IQD gene families in terms of gene structure, chromosome location, predicted protein properties and motifs, phylogenetic relationships, and evolutionary history. The existence of an IQD-like gene in bryophytes suggests that IQD proteins are an ancient family of calmodulin-binding proteins and arose during the early evolution of land plants. Comparative phylogenetic analyses indicate that the major IQD gene lineages originated before the monocot-eudicot divergence. The extant IQD loci in Arabidopsis primarily resulted from segmental duplication and reflect preferential retention of paralogous genes, which is characteristic for proteins with regulatory functions. Interaction of IQD1 and IQD20 with calmodulin and the presence of predicted calmodulin binding sites in all IQD family members suggest that IQD proteins are a new class of calmodulin targets. The basic isoelectric point of IQD proteins and their frequently predicted nuclear localization suggest that IQD proteins link calcium signaling pathways to the regulation of gene expression. Our comparative genomics analysis of IQD genes and encoded proteins in two model plant species provides the first step towards the functional dissection of this emerging family of putative calmodulin targets.
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