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Publikationen - Stress- und Entwicklungsbiologie

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Publikation

Varet, A.; Parker, J.; Tornero, P.; Nass, N.; Nürnberger, T.; Dangl, J. L.; Scheel, D.; Lee, J.; NHL25 and NHL3, Two NDR1/HIN1-Like Genes in Arabidopsis thaliana with Potential Role(s) in Plant Defense Mol. Plant Microbe Interact. 15, 608-616, (2002) DOI: 10.1094/MPMI.2002.15.6.608

The Arabidopsis genome contains 28 genes with sequence homology to the Arabidopsis NDR1 gene and the tobacco HIN1 gene. Expression analysis of eight of these genes identified two (NHL25 and NHL3 for NDR1/HIN1-like) that show pathogen-dependent mRNA accumulation. Transcripts did not accumulate during infection with virulent Pseudomonas syringae pv. tomato DC3000 but did accumulate specifically when the bacteria carried any of the four avirulence genes avrRpm1, avrRpt2, avrB, or avrRps4. Furthermore, expression of avrRpt2 in plants containing the corresponding resistance gene, RPS2, was sufficient to induce transcript accumulation. However, during infection with an avirulent oomycete, Peronospora parasitica isolate Cala-2, only NHL25 expression was reproducibly induced. Salicylic acid (SA) treatment can induce expression of NHL25 and NHL3. Studies performed on nahG plants showed that, during interaction with avirulent bacteria, only the expression of NHL25 but not that of NHL3 was affected. This suggests involvement of separate SA-dependent and SA-independent pathways, respectively, in the transcriptional activation of these genes. Bacteria-induced gene expression was not abolished in ethylene- (etr1-3 and ein2-1) and jasmonate- (coi1-1) insensitive mutants or in mutants impaired in disease resistance (ndr1-1 and pad4-1). Interestingly, NHL3 transcripts accumulated after infiltration with the avirulent hrcC mutant of Pseudomonas syringae pv. tomato DC3000 and nonhost bacteria but not with the virulent Pseudomonas syringae pv. tomato DC3000, suggesting that virulent bacteria may suppress NHL3 expression during pathogenesis. Hence, the expression patterns and sequence homology to NDR1 and HIN1 suggest one or more potential roles for these genes in plant resistance.
Publikation

van't Slot, K. A. E.; Knogge, W.; A Dual Role for Microbial Pathogen-Derived Effector Proteins in Plant Disease and Resistance Crit. Rev. Plant Sci. 21, 229-271, (2002) DOI: 10.1080/0735-260291044223

Many proteins from plant pathogens affecting the interaction with the host plant have dual functions: they promote virulence on the host species and they function as avirulence determinants by eliciting defense reactions in host cultivars expressing the appropriate resistance genes. In viruses all proteins encoded by the small genomes can be expected to be essential for viral development in the host. However, in different plants surveillance systems have evolved that are able to recognize most of these proteins. Bacteria and fungi have specialized pathogenicity and virulence genes. Many of the latter were originally identified through the resistance gene-dependent elicitor activity of their products. Their role in virulence only became apparent when they were inactivated or transferred to different microbes or after their ectopic expression in host plants. Many microbes appear to maintain these genes despite their disadvantageous effect, introducing only few mutations to abolish the interaction of their products with the plant recognition system. This has been interpreted as been indicative of a virulence function of the gene products that is not impaired by the mutations. Alternatively, in particular in bacteria there is now evidence that pathogenicity was acquired through horizontal gene transfer. Genes supporting virulence in the donor organism's original host appear to have traveled along. Being gratuitous in the new situation, they may have been inactivated without loss of any beneficial function for the pathogen.
Publikation

Petters, J.; Göbel, C.; Scheel, D.; Rosahl, S.; A Pathogen-Responsive cDNA from Potato Encodes a Protein with Homology to a Phosphate Starvation-Induced Phosphatase Plant Cell Physiol. 43, 1049-1053, (2002) DOI: 10.1093/pcp/pcf117

Infiltration of potato leaves with the phytopathogenic bacteria Pseudomonas syringae pv. maculicola induces local and systemic defense gene expression as well as increased resistance against subsequent pathogen attacks. By cDNA-AFLP a gene was identified that is activated locally in potato leaves in response to bacterial infiltration and after infection with Phytophthora infestans, the causal agent of late blight disease. The encoded protein has high homology to a phosphate starvation-induced acid phosphatase from tomato. Possibly, decreased phosphate availability after pathogen infection acts as a signal for the activation of the potato phosphatase gene.
Publikation

Lee, J.; Rudd, J. J.; Calcium-dependent protein kinases: versatile plant signalling components necessary for pathogen defence Trends Plant Sci. 7, 97-98, (2002) DOI: 10.1016/S1360-1385(02)02229-X

Plant stress adaptation often uses changes in cytosolic Ca2+ to bring about responses via changing the activity of Ca2+-sensor proteins including Ca2+-dependent protein kinases (CDPK). The activity of a tobacco CDPK(s) is essential for elicitation of the hypersensitive reaction, a typical plant defence response. Moreover, it is becoming apparent that CDPKs might also facilitate cross-talk between different Ca2+-mediated stress signalling pathways.
Publikation

Landtag, J.; Baumert, A.; Degenkolb, T.; Schmidt, J.; Wray, V.; Scheel, D.; Strack, D.; Rosahl, S.; Accumulation of tyrosol glucoside in transgenic potato plants expressing a parsley tyrosine decarboxylase Phytochemistry 60, 683-689, (2002) DOI: 10.1016/S0031-9422(02)00161-9

As part of the response to pathogen infection, potato plants accumulate soluble and cell wall-bound phenolics such as hydroxycinnamic acid tyramine amides. Since incorporation of these compounds into the cell wall leads to a fortified barrier against pathogens, raising the amounts of hydroxycinnamic acid tyramine amides might positively affect the resistance response. To this end, we set out to increase the amount of tyramine, one of the substrates of the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction, by placing a cDNA encoding a pathogen-induced tyrosine decarboxylase from parsley under the control of the 35S promoter and introducing the construct into potato plants via Agrobacterium tumefaciens-mediated transformation. While no alterations were observed in the pattern and quantity of cell wall-bound phenolic compounds in transgenic plants, the soluble fraction contained several new compounds. The major one was isolated and identified as tyrosol glucoside by liquid chromatography–electrospray ionization–high resolution mass spectrometry and NMR analyses. Our results indicate that expression of a tyrosine decarboxylase in potato does not channel tyramine into the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction but rather unexpectedly, into a different pathway leading to the formation of a potential storage compound.Expression of a parsley tyrosine decarboxylase in potato unexpectedly channels tyramine into a pathway leading to the formation of tyrosol glucoside.
Publikation

Landgraf, P.; Feussner, I.; Hunger, A.; Scheel, D.; Rosahl, S.; Systemic Accumulation of 12-oxo-phytodienoic Acid in SAR-induced Potato Plants Eur. J. Plant Pathol. 108, 279-283, (2002) DOI: 10.1023/A:1015132615650

In potato plants induced for systemic resistance by infiltration with Pseudomonas syringae pv. maculicola, 12-oxo-phytodienoic acid (OPDA) accumulated in infiltrated leaves as well as in non-treated leaves of infected plants. In contrast, jasmonic acid (JA) levels increased only in infiltrated leaves, suggesting that the biosynthetic precursor of JA, OPDA, might play a role in systemic acquired resistance.
Publikation

Brunner, F.; Rosahl, S.; Lee, J.; Rudd, J. J.; Geiler, C.; Kauppinen, S.; Rasmussen, G.; Scheel, D.; Nürnberger, T.; Pep-13, a plant defense-inducing pathogen-associated pattern from Phytophthora transglutaminases EMBO J. 21, 6681-6688, (2002) DOI: 10.1093/emboj/cdf667

Innate immunity, an ancient form of defense against microbial infection, is well described for animals and is also suggested to be important for plants. Discrimination from self is achieved through receptors that recognize pathogen‐associated molecular patterns (PAMPs) not found in the host. PAMPs are evolutionarily conserved structures which are functionally important and, thus, not subject to frequent mutation. Here we report that the previously described peptide elicitor of defense responses in parsley, Pep‐13, constitutes a surface‐exposed fragment within a novel calcium‐dependent cell wall transglutaminase (TGase) from Phytophthora sojae . TGase transcripts and TGase activity are detectable in all Phytophthora species analyzed, among which are some of the most destructive plant pathogens. Mutational analysis within Pep‐13 identified the same amino acids indispensable for both TGase and defense‐eliciting activity. Pep‐13, conserved among Phytophthora TGases, activates defense in parsley and potato, suggesting its function as a genus‐specific recognition determinant for the activation of plant defense in host and non‐host plants. In summary, plants may recognize PAMPs with characteristics resembling those known to trigger innate immune responses in animals.
Publikation

Brunner, F.; Wirtz, W.; Rose, J. K. C.; Darvill, A. G.; Govers, F.; Scheel, D.; Nürnberger, T.; A β-glucosidase/xylosidase from the phytopathogenic oomycete, Phytophthora infestans Phytochemistry 59, 689-696, (2002) DOI: 10.1016/S0031-9422(02)00045-6

An 85-kDa β-glucosidase/xylosidase (BGX1) was purified from the axenically grown phytopathogenic oomycete, Phytophthora infestans. The bgx1 gene encodes a predicted 61-kDa protein product which, upon removal of a 21 amino acid leader peptide, accumulates in the apoplastic space. Extensive N-mannosylation accounts for part of the observed molecular mass difference. BGX1 belongs to family 30 of the glycoside hydrolases and is the first such oomycete enzyme deposited in public databases. The bgx1 gene was found in various Phytophthora species, but is apparently absent in species of the related genus, Pythium. Despite significant sequence similarity to human and murine lysosomal glucosylceramidases, BGX1 demonstrated neither glucocerebroside nor galactocerebroside-hydrolyzing activity. The native enzyme exhibited glucohydrolytic activity towards 4-methylumbelliferyl (4-MU) β-d-glucopyranoside and, to lesser extent, towards 4-MU-d-xylopyranoside, but not towards 4-MU-β-d-glucopyranoside. BGX1 did not hydrolyze carboxymethyl cellulose, cellotetraose, chitosan or xylan, suggesting high substrate specificity and/or specific cofactor requirements for enzymatic activity.A β-glucosidase/xylosidase was purified from the phytopathogenic oomycete, Phytophthora infestans. The encoding gene is the first such sequence reported from a species of the kingdom chromista.
Publikation

Bloß, T.; Clemens, S.; Nies, D. H.; Characterization of the ZAT1p zinc transporter from Arabidopsis thaliana in microbial model organisms and reconstituted proteoliposomes Planta 214, 783-791, (2002) DOI: 10.1007/s00425-001-0677-1

The ZAT1p zinc transporter from Arabidopsis thaliana (L.) Heynh. is a member of the cation diffusion facilitator (CDF) protein family. When heterologously expressed in Escherichia coli, ZAT1p bound zinc in a metal blot. Binding of zinc occurred mainly to the hydrophilic amino acid region from H182 to H232. A ZAT1p/ZAT1p*Δ(M1–I25) protein mixture was purified and reconstituted into proteoliposomes. Uptake of zinc into the proteoliposomes did not require a proton gradient across the liposomal membrane. ZAT1p did not transport cobalt, and transported cadmium at only 1% of the zinc transport rate. ZAT1p functioned as an uptake system for 65Zn2+ in two strains of the Gram-negative bacterium Ralstonia metallidurans, which were different in their content of zinc-efflux systems. The ZAT1 gene did not rescue increased zinc sensitivity of a ΔZRC1 single-mutant strain or of a ΔZRC1 ΔCOT1 double-mutant strain of Saccharomyces cerevisiae, but ZAT1 complemented this phenotype in a ΔSpZRC1 mutant strain of Schizosaccharomyces pombe.
Publikation

Ichimura, K.; Shinozaki, K.; Tena, G.; Sheen, J.; Henry, Y.; Champion, A.; Kreis, M.; Zhang, S.; Hirt, H.; Wilson, C.; Heberle-Bors, E.; Ellis, B. E.; Morris, P. C.; Innes, R. W.; Ecker, J. R.; Scheel, D.; Klessig, D. F.; Machida, Y.; Mundy, J.; Ohashi, Y.; Walker, J. C.; Mitogen-activated protein kinase cascades in plants: a new nomenclature Trends Plant Sci. 7, 301-308, (2002) DOI: 10.1016/S1360-1385(02)02302-6

Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules in eukaryotes, including yeasts, animals and plants. These protein phosphorylation cascades link extracellular stimuli to a wide range of cellular responses. In plants, MAPK cascades are involved in responses to various biotic and abiotic stresses, hormones, cell division and developmental processes. Completion of the Arabidopsis genome-sequencing project has revealed the existence of 20 MAPKs, 10 MAPK kinases and 60 MAPK kinase kinases. Here, we propose a simplified nomenclature for Arabidopsis MAPKs and MAPK kinases that might also serve as a basis for standard annotation of these gene families in all plants.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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