Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Recognition of pathogen attack or elicitation with pathogen-associated molecular patterns (PAMPs) leads to defense signaling that includes activation of the three mitogen-activated protein kinases (MPKs), MPK3, MPK4 and MPK6 in Arabidopsis. Recently, we demonstrated the activation of a fourth MPK, MPK11, after treatment with flg22, a 22 amino acid PAMP derived from bacterial flagellin. Here, we extended the study by examining elicitation with two other PAMPs, elf18 (derived from bacterial elongation factor EF-Tu) and ch8 (N-acetylchitooctaose derived from fungal chitin). Both PAMPs led to rapid MPK11 transcript accumulation and increased MPK11 kinase activity, suggesting that multiple PAMPs (or stresses) can activate MPK11. However, probably due to functional redundancies, bacteria-induced phytoalexin accumulation does not absolutely require MPK11.
Publikation
Eschen-Lippold, L.; Lübken, T.; Smolka, U.; Rosahl, S.;Characterization of potato plants with reduced StSYR1 expressionPlant Signal Behav.7559-562(2012)DOI: 10.4161/psb.19866
Vesicle fusion processes in plants are important for both development and stress responses. Transgenic potato plants with reduced expression of SYNTAXIN-RELATED1 (StSYR1), a gene encoding the potato homolog of Arabidopsis PENETRATION1 (AtPEN1), display spontaneous necrosis and chlorosis at later stages of development. In accordance with this developmental defect, tuber number, weight and overall yield are significantly reduced in StSYR1-RNAi lines. Enhanced resistance of StSYR1-RNAi plants to Phytophthora infestans, the causal agent of late blight disease of potato, correlates with enhanced levels of salicylic acid, whereas levels of 12-oxophytodienoic acid and jasmonic acid are unaltered. Cultured cells of StSYR1-RNAi lines secrete at least two compounds which are not detectable in the supernatant of control cells, suggesting an involvement of StSYR1 in secretion processes to the apoplast.
Publikation
Dissmeyer, N.; Weimer, A. K.; De Veylder, L.; Novak, B.; Schnittger, A.;The regulatory network of cell-cycle progression is fundamentally different in plants versus yeast or metazoansPlant Signal Behav.51613-1618(2010)DOI: 10.4161/psb.5.12.13969
Plant growth and proliferation control is coming into a global focus due to recent ecological and economical developments. Plants represent not only the largest food supply for mankind but also may serve as a global source of renewable energies. However, plant breeding has to accomplish a tremendous boost in yield to match the growing demand of a still rapidly increasing human population. Moreover, breeding has to adjust to changing environmental conditions, in particular increased drought. Regulation of cell-cycle control is a major determinant of plant growth and therefore an obvious target for plant breeding. Furthermore, cell-cycle control is also crucial for the DNA damage response, for instance upon irradiation. Thus, an in-depth understanding of plant cell-cycle regulation is of importance beyond a scientific point of view. The mere presence of many conserved core cell-cycle regulators, e.g. CDKs, cyclins, or CDK inhibitors, has formed the idea that the cell cycle in plants is exactly or at least very similarly controlled as in yeast or human cells. Here together with a recent publication we demonstrate that this dogma is not true and show that the control of entry into mitosis is fundamentally different in plants versus yeast or metazoans. Our findings build an important base for the understanding and ultimate modulation of plant growth not only during unperturbed but also under harsh environmental conditions.
Publikation
Wasternack, C.; Xie, D.;The genuine ligand of a jasmonic acid receptor: Improved analysis of jasmonates is now requiredPlant Signal Behav.5337-340(2010)DOI: 10.4161/psb.5.4.11574
Jasmonic acid (JA), its metabolites, such as the methyl ester or amino acid conjugates as well as its precursor 12-oxophytodienoic acid (OPDA) are lipid-derived signals. JA, OPDA and JA-amino acid conjugates are known to function as signals in plant stress responses and development. More recently, formation of JA-amino acid conjugates and high biological activity of JA-Isoleucine (JA-Ile) were found to be essential in JA signalling. A breakthrough was the identification of JAZ proteins which interact with the F-box protein COI1 if JA-Ile is bound. This interaction leads to proteasomal degradation of JAZs being negative regulators of JA-induced transcription. Surprisingly, a distinct stereoisomer of JA-Ile, the (+)-7-iso-JA-Ile ((3R,7S) form) is most active. Coronatine, a bacterial phytotoxine with an identical stereochemistry at the cyclopentanone ring, has a similar bioactivity . This was explained by the recent identification of COI1 as the JA receptor and accords well with molecular modelling studies. Whereas over the last two decades JA was quantified to describe any JA dependent process, now we have to take into account a distinct stereoisomer of JA-Ile. Until recently a quantitative analysis of (+)-7-iso-JA-Ile was missing presumable due to its equilibration to (-)-JA-Ile. Now such an analysis was achieved. These aspects will be discussed based on our new knowledge on JA perception and signalling.