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Publikationen - Molekulare Signalverarbeitung

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Publikation

Leon-Reyes, A.; Van der Does, D.; De Lange, E. S.; Delker, C.; Wasternack, C.; Van Wees, S. C. M.; Ritsema, T.; Pieterse, C. M. J.; Salicylate-mediated suppression of jasmonate-responsive gene expression in Arabidopsis is targeted downstream of the jasmonate biosynthesis pathway Planta 232, 1423-1432, (2010) DOI: 10.1007/s00425-010-1265-z

Jasmonates (JAs) and salicylic acid (SA) are plant hormones that play pivotal roles in the regulation of induced defenses against microbial pathogens and insect herbivores. Their signaling pathways cross-communicate providing the plant with a regulatory potential to finely tune its defense response to the attacker(s) encountered. In Arabidopsis thaliana, SA strongly antagonizes the jasmonic acid (JA) signaling pathway, resulting in the downregulation of a large set of JA-responsive genes, including the marker genes PDF1.2 and VSP2. Induction of JA-responsive marker gene expression by different JA derivatives was equally sensitive to SA-mediated suppression. Activation of genes encoding key enzymes in the JA biosynthesis pathway, such as LOX2, AOS, AOC2, and OPR3 was also repressed by SA, suggesting that the JA biosynthesis pathway may be a target for SA-mediated antagonism. To test this, we made use of the mutant aos/dde2, which is completely blocked in its ability to produce JAs because of a mutation in the ALLENE OXIDE SYNTHASE gene. Mutant aos/dde2 plants did not express the JA-responsive marker genes PDF1.2 or VSP2 in response to infection with the necrotrophic fungus Alternaria brassicicola or the herbivorous insect Pieris rapae. Bypassing JA biosynthesis by exogenous application of methyl jasmonate (MeJA) rescued this JA-responsive phenotype in aos/dde2. Application of SA suppressed MeJA-induced PDF1.2 expression to the same level in the aos/dde2 mutant as in wild-type Col-0 plants, indicating that SA-mediated suppression of JA-responsive gene expression is targeted at a position downstream of the JA biosynthesis pathway.
Publikation

Delker, C.; Raschke, A.; Quint, M.; Auxin dynamics: the dazzling complexity of a small molecule’s message Planta 227, 929-941, (2008) DOI: 10.1007/s00425-008-0710-8

The phytohormone auxin is a potent regulator of plant development. Since its discovery in the beginning of the twentieth century many aspects of auxin biology have been extensively studied, ranging from biosynthesis and metabolism to the elucidation of molecular components of downstream signaling. With the identification of the F-box protein TIR1 as an auxin receptor a major breakthrough in understanding auxin signaling has been achieved and recent modeling approaches have shed light on the putative mechanisms underlying the establishment of auxin gradients and maxima essential for many auxin-regulated processes. Here, we review these and other recent advances in unraveling the entanglement of biosynthesis, polar transport and cellular signaling events that allow small auxinic molecules to facilitate their complex regulatory action.
Publikation

Pedranzani, H.; Sierra-de-Grado, R.; Vigliocco, A.; Miersch, O.; Abdala, G.; Cold and water stresses produce changes in endogenous jasmonates in two populations of Pinus pinaster Ait Plant Growth Regul. 52, 111-116, (2007) DOI: 10.1007/s10725-007-9166-2

There is considerable evidence suggesting that jasmonates (JAs) play a role in plant resistance against abiotic stress. It is well known that in Angiosperms JAs are involved in the defense response, however there is little information about their role in Gymnosperms. Our proposal was to study the involvement of JAs in Pinus pinaster Ait. reaction to cold and water stress, and to compare the response of two populations of different provenances (Gredos and Bajo Tiétar) to these stresses. We detected 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and the hydroxylates 11-hydroxyjasmonate and 12-hydroxyjasmonate in foliage and shoots of P. pinaster plants. The response of the Gredos population to cold stress differed from that of Bajo Tiétar. Gredos plants showed a lower JA-basal level than Bajo Tiétar; under cold stress JA increased twofold at 72 h, while it decreased in Bajo Tiétar plants. The hydroxylates slightly increased in both populations due to cold stress treatment. Under water stress, plants from Gredos showed a remarkable JA-increase; thus the JA-response was much more prominent under water stress than under cold stress. In contrast, no change was found in JA-level in Bajo Tiétar plants under water stress. The level of JA-precursor, OPDA, was very low in control plants from Gredos and Bajo Tiétar. Under water stress OPDA increased only in plants from Bajo Tiétar. Therefore, we inform here of a different JAs-accumulation pattern after the stress treatment in P. pinaster from two provenances, and suggest a possible correlation with adaptations to diverse ecological conditions.
Publikation

Meixner, C.; Ludwig-Müller, J.; Miersch, O.; Gresshoff, P.; Staehelin, C.; Vierheilig, H.; Lack of mycorrhizal autoregulation and phytohormonal changes in the supernodulating soybean mutant nts1007 Planta 222, 709-715, (2005) DOI: 10.1007/s00425-005-0003-4

Autoregulatory mechanisms have been reported in the rhizobial and the mycorrhizal symbiosis. Autoregulation means that already existing nodules or an existing root colonization by an arbuscular mycorrhizal fungus systemically suppress subsequent nodule formation/root colonization in other parts of the root system. Mutants of some legumes lost their ability to autoregulate the nodule number and thus display a supernodulating phenotype. On studying the effect of pre-inoculation of one side of a split-root system with an arbuscular mycorrhizal fungus on subsequent mycorrhization in the second side of the split-root system of a wild-type soybean (Glycine max L.) cv. Bragg and its supernodulating mutant nts1007, we observed a clear suppressional effect in the wild-type, whereas further root colonization in the split-root system of the mutant nts1007 was not suppressed. These data strongly indicate that the mechanisms involved in supernodulation also affect mycorrhization and support the hypothesis that the autoregulation in the rhizobial and the mycorrhizal symbiosis is controlled in a similar manner. The accumulation patterns of the plant hormones IAA, ABA and Jasmonic acid (JA) in non-inoculated control plants and split-root systems of inoculated plants with one mycorrhizal side of the split-root system and one non-mycorrhizal side, indicate an involvement of IAA in the autoregulation of mycorrhization. Mycorrhizal colonization of soybeans also resulted in a strong induction of ABA and JA levels, but on the basis of our data the role of these two phytohormones in mycorrhizal autoregulation is questionable.
Publikation

Abdala, G.; Miersch, O.; Kramell, R.; Vigliocco, A.; Agostini, E.; Forchetti, G.; Alemano, S.; Jasmonate and octadecanoid occurrence in tomato hairy roots. Endogenous level changes in response to NaCl Plant Growth Regul. 40, 21-27, (2003) DOI: 10.1023/A:1023016412454

Jasmonic acid biosynthesis occurs in leaves and there is also evidence of a similar pathway in roots. The expression of lipoxygenase, allene oxide cyclase and low amounts of transcripts of allene oxide synthase in tomato roots indicates that some steps of the jasmonate synthesis may occur in these organs. Thus, the aim of the present work was to study the jasmonate and octadecanoid occurrence in tomato roots using isolated cultures of hairy roots. These were obtained by the transformation of cv. Pera roots with Agrobacterium rhyzogenes. Also we investigated the effect of NaCl stress on the endogenous levels of these compounds. Jasmonic acid, 12-oxophytodienoic acid and their methylated derivatives, as well as a jasmonate-isoleucine conjugate, were present in control hairy roots of 30 d of culture. The 12-oxophytodienoic acid and its methylated derivative showed higher levels than jasmonic acid and its methylated form, although the content of the conjugate was the same as that of jasmonic acid. After salinization of hairy roots for 14, 20 and 30 d, free jasmonates and octadecanoids were measured. Fourteen days after salt treatment, increased levels of these compounds were found, jasmonic acid and 12-oxophytodienoic acid showed the most remarkable rise. 11-OH-jasmonic acid was found at 14 d of culture in control and salt-treated hairy roots; whereas the 12-OH- form of jasmonic acid was only detected in the salt-treated hairy roots. Agrobacterium rhizogenes cultures did not produce jasmonates and/or octadecanoids.
Publikation

Abdala, G.; Castro, G.; Miersch, O.; Pearce, D.; Changes in jasmonate and gibberellin levels during development of potato plants (Solanum tuberosum) Plant Growth Regul. 36, 121-126, (2002) DOI: 10.1023/A:1015065011536

Among the multiple environmental signals and hormonal factors regulatingpotato plant morphogenesis and controlling tuber induction, jasmonates (JAs)andgibberellins (GAs) are important components of the signalling pathways in theseprocesses. In the present study, with Solanum tuberosum L.cv. Spunta, we followed the endogenous changes of JAs and GAs during thedevelopmental stages of soil-grown potato plants. Foliage at initial growthshowed the highest jasmonic acid (JA) concentration, while in roots the highestcontent was observed in the stage of tuber set. In stolons at the developmentalstage of tuber set an important increase of JA was found; however, in tubersthere was no change in this compound during tuber set and subsequent growth.Methyl jasmonate (Me-JA) in foliage did not show the same pattern as JA; Me-JAdecreased during the developmental stages in which it was monitored, meanwhileJA increased during those stages. The highest total amount of JAs expressed asJA + Me-JA was found at tuber set. A very important peak ofJA in roots was coincident with that observed in stolons at tuber set. Also, aprogressive increase of this compound in roots was shown during the transitionof stolons to tubers. Of the two GAs monitored, gibberellic acid(GA3) was the most abundant in all the organs. While GA1and GA3 were also found in stolons at the time of tuber set, noothermeasurements of GAs were obtained for stolons at previous stages of plantdevelopment. Our results indicate that high levels of JA and GAs are found indifferent tissues, especially during stolon growth and tuber set.
Publikation

Nibbe, M.; Hilpert, B.; Wasternack, C.; Miersch, O.; Apel, K.; Cell death and salicylate- and jasmonate-dependent stress responses in Arabidopsis are controlled by single cet genes Planta 216, 120-128, (2002) DOI: 10.1007/s00425-002-0907-1

The jasmonic acid (JA)-dependent regulation of the Thi2.1 gene had previously been exploited for setting up a genetic screen for the isolation of signal transduction mutants of Arabidopsis thaliana (L.) Heynh. that constitutively express the thionin gene. Several cet mutants had been isolated which showed a constitutive expression of the thionin gene. These cet mutants, except for one, also showed spontaneous leaf cell necrosis and were up-regulated in the expression of the PR1 gene, reactions often associated with the systemic acquired resistance (SAR) pathway. Four of these cet mutants, cet1, cet2, cet3 and cet4.1 were crossed with the fad triple and coi1 mutants that are blocked at two steps within the JA-dependent signaling pathway, and with transgenic NahG plants that are deficient in salicylic acid (SA) and are unable to activate SAR. Analysis of the various double-mutant lines revealed that the four cet genes act within a signaling cascade at or prior to branch points from which not only JA-dependent signals but also SA-dependent signaling and cell death pathways diverge.
Publikation

Ortel, B.; Atzorn, R.; Hause, B.; Feussner, I.; Miersch, O.; Wasternack, C.; Jasmonate-induced gene expression of barley (Hordeum vulgare) leaves - the link between jasmonate and abscisic acid Plant Growth Regul. 29, 113-122, (1999) DOI: 10.1023/A:1006212017458

In barley leaves a group of genes is expressed in response to treatment with jasmonates and abscisic acid (ABA) [21]. One of these genes coding for a jasmonate-induced protein of 23 kDa (JIP-23) was analyzed to find out the link between ABA and jasmonates by recording its expression upon modulating independently, the endogenous level of both of them. By use of inhibitors of JA synthesis and ABA degradation, and the ABA-deficient mutant Az34, as well as of cultivar-specific differences, it was shown that endogenous jasmonate increases are necessary and sufficient for expression of this gene. The endogenous rise of ABA did not induce synthesis of JIP-23, whereas exogenous ABA did not act via jasmonates. Different signalling pathways are suggested and discussed.
Publikation

Görschen, E.; Dunaeva, M.; Hause, B.; Reeh, I.; Wasternack, C.; Parthier, B.; Expression of the ribosome-inactivating protein JIP60 from barley in transgenic tobacco leads to an abnormal phenotype and alterations on the level of translation Planta 202, 470-478, (1997) DOI: 10.1007/s004250050151

In this paper we report the in-planta activity of the ribosome-inactivating protein JIP60, a 60-kDa jasmonate-induced protein from barley (Hordeum vulgare L.), in transgenic tobacco (Nicotiana tabacum L.) plants. All plants expressing the complete JIP60 cDNA under the control of the cauliflower mosaic virus (CaMV) 35S promoter exhibited conspicuous and similar phenotypic alterations, such as slower growth, shorter internodes, lanceolate leaves, reduced root development, and premature senescence of leaves. Microscopic inspection of developing leaves showed a loss of residual meristems and higher degree of vacuolation of mesophyll cells as compared to the wild type. When probed with an antiserum which was immunoreactive against both the N- and the C-terminal half of JIP60, a polypeptide with a molecular mass of about 30 kDa, most probably a processed JIP60 product, could be detected. Phenotypic alterations could be correlated with the differences in the detectable amount of the JIP60 mRNA and processed JIP60 protein. The protein biosynthesis of the transformants was characterized by an increased polysome/monosome ratio but a decreased in-vivo translation activity. These findings suggest that JIP60 perturbs the translation machinery in planta. An immunohistological analysis using the JIP60 antiserum indicated that the immunoreactive polypeptide(s) are located mainly in the nucleus of transgenic tobacco leaf cells and to a minor extent in the cytoplasm.
Publikation

Feussner, I.; Hause, B.; Nellen, A.; Wasternack, C.; Kindl, H.; Lipid-body lipoxygenase is expressed in cotyledons during germination prior to other lipoxygenase forms Planta 198, 288-293, (1996) DOI: 10.1007/BF00206255

Lipid bodies are degraded during germination. Whereas some proteins, e.g. oleosins, are synthesized during the formation of lipid bodies of maturating seeds, a new set of proteins, including a specific form of lipoxygenase (LOX; EC 1.13.11.12), is detectable in lipid bodies during the stage of fat degradation in seed germination. In cotyledons of cucumber (Cucumis sativus L.) seedlings at day 4 of germination, the most conspicuous staining with anti-LOX antibodies was observed in the cytosol. At very early stages of germination, however, the LOX form present in large amounts and synthesized preferentially was the lipid-body LOX. This was demonstrated by immunocytochemical staining of cotyledons from 1-h and 24-h-old seedlings: the immunodecoration of sections of 24-h-old seedlings with anti-LOX antiserum showed label exclusively correlated with lipid bodies of around 3 μm in diameter. In accordance, the profile of LOX protein isolated from lipid bodies during various stages of germination showed a maximum at day 1. By measuring biosynthesis of the protein in vivo we demonstrated that the highest rates of synthesis of lipid-body LOX occurred at day 1 of germination. The early and selective appearance of a LOX form associated with lipid bodies at this stage of development is discussed.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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