IPB Newsletter January 2013

Editorial

Dear reader, ted a high publication record on phytohormones, biosyntheses and further topics so that we can look back on a very busy and Last year was overabundant with extraordi- successful year 2012. nary activities. The 20th IPB anniversary cel- ebration attracted all institute members and This shall suffice, however, in terms of our track record: We are many guests and was an all-out success. facing a similarly exciting year with interesting challenges. I trust The event was fired up by the ‘Rolling Mill- we are all aware of the fact that we have to and intend to give Stones’ with drums and trumpets. Numer- proof of our excellence, strategies and expertise in a very spe- ous guests of honor, such as Leopoldina cial manner in 2013. Another seven-year-period has elapsed: President Jörg Hacker and Leibniz Community Presi- That is, the IPB will be up for re-evaluation by the Senate of the dent Karl Ulrich Mayer, kindly attended the ceremony – surely also Leibniz Community (WGL) in summer this year. We are looking prompted by the simultaneous celebration of the 80th birthday of forward with interest to this assessment and, of course, hope for Benno Parthier, our former director and former Leopoldina presi- a positive outcome. dent. This public function was a great reward on its own but it was getting even better: Right on time, Marcel Quint treated us to a very special anniversary gift – an article in Nature with title page In this spirit, I would like to wish all of you a successful 2013. and cover story. He had produced the paper in a joint effort with May it be a busy, brilliant and brightly-colored year! Ivo Große (MLU) and four PhD students in all of eighteen months and – due to high-performance computer technology – without a single lab experiment. This is what we call an unparalleled low- Best regards, cost and efficient approach. Also all other IPB researchers boas- Sylvia Pieplow

1 IPB Newsletter January 2013

Table of contents

20 Years Of IPB...... 3 Emergence into a new era...... 3 Highlights from 20 years of research...... 5

Cover Story...... 11 From Arabidopsis to Zebrafish: Is the hourglass ticking everywhere?...... 11

News Ticker: Research...... 15 Phytohormones I: Auxin acts through the co receptor...... 15 Biosynthesis: Fragrant raw material in two steps...... 17 From to Ambrox® - The secret of Chanel and Davidoff...... 18 New reagent: IPB one-pot substance...... 19

Imprint...... 19 2 20 Years Of IPB

Emergence into a new era

The 20th anniversary of the reestablishment of the IPB was celebrated in a joyful atmosphere and relaxed mood by all institute members on 14 September 2012. The festive event also celebrated the 80th birthday of our founding director, professor Benno Parthier, who steered the institute’s fate supremely well into the new science system of the Federal Republic of Germany. While the last issue was devoted to the IPB foundation period, this newsletter issue will give a brief historic survey of structural changes and scientific highlights in the past 20 years.

he Institute of Plant Biochemistry (IPB) was re- gal details of the foundation’s purpose in its stat- of the new department Secondary Metabolism. Testablished on 1 January 1992 with the status utes that was adopted in May 1993. Advisory and Lothar Franzen took on the administrative manage- of a Public Law Foundation under the protection controlling bodies were subsequently founded, ment of the institute in the same year. and supervision of the government of the Federal namely the Scientific Advisory Board chaired by In 1994, the IPB managed to State of Saxony-Anhalt. As a member of the Blue Jozef Schell on 6 January 1994 and the Founda- entice Dierk Scheel of Cologne- List Association (later: WGL) it is co-financed in tion Board on 7 January 1994. based Max Planck Institute for equal parts by the German national and federal Plant Breeding Research to be- state governments. ◊ New structures through changing times come head of the Stress Re- search department – today Benno Parthier became its first Department heads and directors Stress and Developmental Biol- executive director and in this ca- The three original scientific depart- ogy. He succeeded Lutz Nover who had accepted pacity swiftly processed all pend- ments were complemented by a a position at Universität Frankfurt/Main in 1992. ing administrative tasks and was fourth division as recommended by instrumental in further implement- the Foundation Committee. In 1993, From 1998, the institute had found in Dierk Scheel ing recommendations given by the Dieter Strack of Technische Univer- a very prudent and highly committed executive di- German Science Council. One of the initial tasks sität Braunschweig was appointed rector. The organizational structure into four sci- was to stipulate organizational, structural and le- by the institute as competent head entific departments was retained but there were

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several changes in names and ori- activities after his retirement. Junior research groups entations and new appointments. In 2009, the institute at- In addition to the IPB depart- Following the age-related retire- tracted Steffen Abel from UC ments, the first Independent Ju- ment of Benno Parthier, in 1999 Davis (US). Under his direc- nior Research Group was found- Toni Kutchan became head of the tion, the department was re- ed in early 2007. Marcel Quint Research department, oriented and renamed into is heading this group, which is which was renamed into Natu- Molecular Signal Processing. working on the topic of Auxin ral Product Biotechnology. The Natural Product Dieter Strack Signaling and Chemistry department faced with a similar situa- terminated his employment in has established itself as a tion when its head Günter Adam retired in 1999. October 2010 and his succes- separate working group in the sor at departmental level be- Molecular Signal Processing de- Under the responsibility of came Alain Tissier of Montpellier. partment. Fur- Ludger Wessjohann this di- He extended the Secondary ther junior re- vision gained new momen- Metabolism department by re- search groups tum from 2000 as Bioor- search into Glandular Trichomes under Marco Trujillo and Nico ganic Chemistry department. and it was renamed into Cell and Metabolic Biol- Dissmeyer were established in Toni Kutchan accepted a post in ogy. Ludger Wessjohann was appointed IPB exec- 2011 to research into ubiqui- the US in 2006 and hence, held utive director in October 2010. tin and protein degradation. the management position only a bit over one year. Lothar Franzen left the institute Dierk Scheel was again appointed executive direc- in 2011 after long years of valu- tor and passed on this position to Dieter Strack in able work and was succeeded 2008. Responsibility for the Natural-Product Bio- as administrative director of technology department was temporarily assumed the IPB by Christiane Cyron *** by Claus Wasternack but completely ceased of Hamburg in October 2011. 4 back to the table of contents 20 Years Of IPB

Scientific highlights - phytohormones, plant stress and natural products at focus of research

◊ Phytohormones 1980s, the institute has analyzed two new sub- 1997 by Claus Wasternack. Until his retirement stance classes that were discussed as new phyto- in 2008, jasmonates were a top research priority All-out research : Brassinosteroids and jasmonates. at the institute, and today is dealt with by Bettina The institute has conducted research and worked Brassinosteroid research officially ceased in Hause. Marcel Quint, Luz Irina A. Calderón Vil- on all known phytohormones in its 50+ years of 1997 with retirement of Günter Adam and petered lalobos and Steffen Abel brought the best-known existence. The early years were devoted to eth- out over the next few years. Molecular jasmo- phytohormones, auxins, back into the focus of re- ylene and abscisic acid (ABA) and predominantly nate research was initiated under Benno Parthier search at the IPB. to cytokinins and gibberellins. Since the early and was continued after his official retirement in

Hormone researchers in the post 1992 IPB era Prof. Günter Adam, Prof. Benno Parthier, Prof. Claus Wasternack, Prof. Bettina Hause, Dr. Marcel Quint, Dr. Luz I.A. Calderón Villalobos and Prof. Steffen Abel (from left to right).

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Jasmonates – quest for their active form relevant receptor and thus triggers the defense ◊ Stress Research Jasmonates (JAs) are acting in a large variety of mechanism (Nat. Chem. Biol. 5: 344-350, 2009). ways as all other phytohormones but play a speci- It is the cis form of the isoleucine conjugate of Plant tolerance to heavy metals fic role in stress defense. After wounding by plant- JA: (+)-7-iso-JA-Ile. The search turned out to be ex- Outstanding research was per- feeding insects, JAs induce for instance a whole tremely difficult because thetrans form the con- formed by Stephan Clemens battery of defense reactions, inter alia, production jugate, (-)- JA-Ile, has a much higher stability and on plant metal balance and of a substance that causes digestion problems thus prevails in the cis/trans mixture of the two heavy-metal resistance in vari- in insect intestines and prompts insects to let go compounds. This result is the first-ever verification ous plant species. Plants, like of the plant. It was soon discovered in the more that only a certain stereoisomeric form of JA-Ile any other organism, have to than 30 years of JA research at the institute that bonds to a JA receptor – a fundamental finding for protect themselves from toxic not only JAs proper but also their derivatives with hormone researchers. heavy metals. Plant root-based various amino acids act as signaling substances. metal transporters do not specifically distinguish This finding enabled identification, isolation and between harmful and useful metals; hence, often characterization of many different JA derivatives toxic metals are absorbed together with essen- with various biological activities. Much knowledge tial metals. Two examples to illustrate this fact was accumulated about fine-tuning JA-regulated are cadmium and zinc; two elements with strong defense processes while the active jasmonate chemical similarities, which only occur together in form – i.e. the molecule that acts as ligand of the nature. While cadmium wreaks all-out havoc in a JA receptor – remained unknown. cell and causes enormous damage, zinc is a co- factor of many enzymes and essential for plants. The underlying reason is its instability. It was not Metal-binding peptides – so-called phytochelatines before 2009 that IPB researchers, in cooperation Jasmonate in its active cis form (left) and inactive trans – enable plants to bind toxic substances, such with teams in Madrid and Stockholm, identified form. as cadmium, arsenic, mercury and copper, and the active form of jasmonate, which bonds to the thus strip them of their reactivity as free ions. This 6 back to the table of contents 20 Years Of IPB

mechanism allows most plants to tolerate low specific tolerance genes but rather to modified concentrations of harmful heavy metals, which are regulation of individual genes. Clarification of ac- accumulated in their roots for good. tivated gene functions will provide fundamental knowledge about the molecular bases of metal To gain a better understanding of the mecha- balance and heavy-metal resistance. nisms of metal absorption, transport and accu- mulation, Stephan Clemens and his colleagues Advanced research in this field has not been con- compared gene activities of two different model ducted at the institute since 2006. Relevant find- plants: Arabidopsis thaliana (mouse-ear or thale ings obtained at the IPB should be integrated, cress) and Arabidopsis halleri (meadow rock- though, into developing practice-oriented reme- cress). Arabidopsis halleri grows on abandoned diation technologies for heavy metal-contaminat- mining waste tips in the Harz Mountains. In ed soils. Improved understanding of heavy metal contrast to its close relative, A. thaliana, A. hal- tolerances could contribute to developing plants leri tolerates cadmium in high concentrations. with a high biomass, fast growth rates and large heavy-metal accumulation capabilities in their The plant is a so-called metal hyper-accumu- Arabidopsis thaliana (left) reacts sensitively to cad- leaves. Such plants would simply be sown on lator, which boasts special buffer mechanisms, mium while Arabidopsis halleri tolerates high toxic contaminated soils and harvested, together with metal concentrations. which permits toxic metals to be transported highly-concentrated toxic metals. into its leaves for accumulation. The compari- son of activities by the Halle-based researchers metal transporters or enzymes, which catalyze yielded the following: Several metal homeosta- synthesis of metal-binding molecules, while the sis genes are more activated in A. halleri than in functions of other genes are still completely un- A. thaliana (Plant Journal 37, 269-281, 2004). known. Hence, plant adaptation to extreme lo- *** Several of such activated genes are coded as cation conditions is not due to the existence of 7 back to the table of contents 20 Years Of IPB

Innate immunity in plants they have hardly modified in the course of evolu- ogenous molecule to plants but was verified in ten Very much like animals, plants have developed in tion. Large numbers of such pathogen-associated different Phytophthora species. In all ten analyzed the course of evolution highly efficient defense molecular patterns (PAMPs) were found in animal species-specific transglutaminases, Pep13 con- strategies against a broad range of hostile invad- pathogens, including cell-wall components of fungi sisted of exactly the same 13 amino acids – hence, ers. Most plants, as all organisms, are permanent- (such as chitin) and bacteria (such as flagellin of it was preserved during species-to-species transi- ly exposed to potential pathogens but rarely catch flagella and flagellates) but also fragments of bac- tion and not subject to any mutation. Replacement a disease. Apparently, plants – similar to animals terial DNA. Such molecular recognition patterns of a single amino acid in the peptide resulted in a – have a kind of basic immunity which prevents were long unknown in plant disease pathogens. functional loss of the relevant transglutaminase. their becoming host plants for pathogenic micro- organisms. The molecular bases of such non-host Dierk Scheel and Thorsten Transglutaminases are enzymes that catalyze resistance are at the focus of IPB stress research. Nürnberger are among the first cross-linking of certain proteins. In animals, they scientists to have discovered a are involved in nerve growth, bone formation and A shared feature of innate immunity in animals and PAMP structure also in a plant- wound healing. Their function in Phytophthora is plants was postulated proceeding from findings pathogenic organism (Science still very much unclear. What has been clarified, on innate immunity response in vertebrates: A po- 276, 2054-2057, 1997). They however, is that transglutaminase triggers de- tential host identifies certain surface structures of found a peptide consisting of fense reactions in various plants even without the a pathogen and classifies such as alien. This dis- 13 amino acids (Pep 13) that pathogen. And if this were not enough: Pep13, a crimination is followed at cellular level by inducing is part of a transglutaminase minute enzyme component, is capable of induc- local inflammatory reactions to prevent multiplica- on the surface of the late blight ing plant protection mechanisms. Injection of this tion and eventually kill the pathogen. Substances pathogen Phytophthora infes- peptide into parsley and potato leaves prompted ,which are identified by a host as alien and fended tans. According to their findings, multiple cellular defense responses in both plants, off are fundamental molecular structures of micro- Pep13 fulfils all criteria defined such as production of phytoalexins, highly-reactive organisms that are wide-spread in the microbial for PAMPs (EMBO J. 21, 6681- oxygen compounds and other anti-microbial sub- world and of such significance for their survival that 6688, 2002). Pep 13 is an ex- stances. Pep13 hence is the first PAMP for plant 8 back to the table of contents 20 Years Of IPB

pathogens. Pep 13 (synthetically produced) is ◊ Active substance research grophorus) a highly-active antibiotic for pyogenic still being used to study plant defense reactions, pathogens and promising candidates for curbing rather than pathogens proper which require cum- New substances for the world late blight in potatoes. bersome cultivation and have to be kept alive. Resistance to antibiotics, new diseases, soil sali- nization, draughts, climate disasters, overpopula- Finding active substances has changed tion, hunger, epidemics – there is a long list of Nowadays one is not searching for individual sub- challenges to be tackled. Plant, fungal and bac- stances – selected organisms are rather combed terial active substances have accompanied man- through for everything that seems to be helpful. kind since its coming into existence in combating Or even for everything that is present (or can be diseases and death. Multiplication of population verified with currently available analytical meth- figures entails increasing problems – this is why ods) – as it may turn out to be helpful in the future. the search for healing substances in nature will re- Modern computer technology enables compre- main an urgent issue for relief and mitigation. The hensive asset surveys of whole substance classes search is currently intensifying: Substances, as per organism. Substance libraries and databases yet unknown but with much-needed effects. Find- are fed with vast numbers of small molecules and ing active substance has always been a charac- complex metabolites; albeit that very few of them teristic pillar in the institute’s research profile. But in terms of their structures and functions. Phytophthora infestans, the late blight pathogen wreaks great havoc on potatoes and tomatoes. apparently it is not enough to consult shamans Most other pants are spared as they are not its host plants. and healers in exotic cultures for plant-based anti- Structure elucidation and synthesis flu agents. Such ethno-pharmacological projects Identification of the most promising candidate are still being pursued at the IPB but our attention substances in laborious bioactivity tests (screen- is increasingly concentrated on active substances ing) is followed by elucidation and, where possi- *** in less-researched organisms, such as fungi and ble, synthesis of their structures. Synthesis is of algae. Our researchers found in fungi (genus Hy- key importance as it preserves natural resources, back to the table of contents 9 20 Years Of IPB

provides sufficient substances for further analy- reaction is a whole library of potentially effective to identify a maximum of one hundred candidates ses and makes researchers more independent substances that is again combed through for the for review in biotests. In-silico screening helped from climatic conditions; most fungi, e.g., are pre- most promising candidates. There is high proba- IPB researchers identify promising molecules to dominantly found in fall. Synthesis is also a pre- bility that among synthetically produced substanc- protect plants from drought stress. condition for active substance optimization. The es there are higher-activity variants with better biological effects of many natural products can be pharmacological profiles than among the original enhanced by minor modifications, such as attach- natural active substances. And: One learns quite ing of functional groups. Targeted modification of incidentally which structure achieves the optimal one molecule, however, presupposes exact know- effect. Potential anti-cancer agents, such as com- ledge, which part of the molecule controls its ef- plex-structured tubulysin were already synthesized *** ficacy. Structure/efficacy analyses are necessary at the IPB in multi-component reactions. and exciting but highly time-consuming. In-silico screening One-pot evolution The whole process is even more efficient when IPB researchers also rely on the random principle. an active substance is initially computer-modeled The multi-component reaction developed at the to develop and optimized versions. Appropriate institute enables assembly of active substances search criteria are defined to comb through mil- from single modules. Minor modifications of indi- lions and millions of molecules in virtual structure vidual modules yield multi-faceted combinations databases for suitable active substances. This and a whole pool of chemical varieties of a given may be, for instance, substances that bind to cer- active substance, which are similar but not identi- tain enzymes and inhibit or activate them. Such cal to their natural paragon. The whole process binding studies of virtual enzyme models limit the is carried out in a single synthesis cycle and in number of potential binding partners. Thus, sever- one reaction vessel. The result of this one-pot al hundred thousand initial structures are analyzed 10 back to the table of contents Cover Story

From Arabidopsis to Zebrafish: Is the hourglass ticking everywhere?

Marcel Quint, in excellent cooperation with Ivo was in 1828 at Albertus-Universität in Königsberg. Still, a technical term was swiftly coined: The Große of Martin-Luther-Universität, succeeded in ‘This was the initial spark for the Baer rule (law of phase of maximal morphological similarity hence- elucidating an evolutionary and developmental bi- the embryo similarity) and the beginning of com- forth was termed phylotypic stage. In the early ology phenomenon of plants. The paper earned parative embryology’, says Marcel Quint, plant ge- 1980s, the term hourglass model of embryogen- the authors the cover story in the Nature October neticist at IPB. What followed was a long time of esis was established as the phylotypic stage was 2012 issue. systematic morphological comparisons of mam- symbolized by the narrow passage at the centre of mal embryos in all conceivable stages. an hourglass. It was only in 2010 that the molecu- his story started with an error. Or more exact- lar cause of this phenomenon was found and the Tly, a bit of negligence to which people may be The state of research evolved through dead-end morphologically-based development model was susceptible in the frenzy of their zest for action. Not streets and wanderings of Meckel‘s recapitulation provided with a genetic foundation. It was verified rarely, such minor slips give rise to major insights. theory and Haeckel’s biogenetic rule by taking up both in zebrafish and fruit fly that in the middle Provided such are not brushed off as side issues. then contemporary findings and glossing over, mer- phase of embryogenesis only the old, less modifi- Karl Ernst von Baer, a German zoologist and a pro- rily meandered through the decades – always dis- able (highly conserved) genes are active (Kalinka gressive thinker in his times, apparently did not do puted and controversially discussed – until it ended et al & Domazet-Loso et al; Nature 468, 2010). the latter when he took down one day: ‘I had pre- in the partly accepted recognition in mid-C20: Em- The old genes have hardly changed for at least a serve embryos of two species in ethyl alcohol and bryos of various vertebrate species pass though billion years and, hence, are almost identical in all forgotten to label the jars. Now I cannot tell, which different stages of similarity in their development species: Accordingly, their embryos are alike also jars holds which species. They could be lizards or from fertilized ova to birth (embryogenesis). While morphologically in shape and structure; they form little birds, or even mammals.’ The apparent simi- they are clearly distinguished from each other at a kind of original-type embryo. ‘It was only those larity of his two preparations made him wonder the beginning and ending of embryogenesis, they genetic correlations that brought acceptance and maybe caused annoyance or doubt – but then achieve a phase halfway through their develop- among experts of the hourglass model as funda- he started to get to the bottom of the matter. That ment where they all look alike. Nobody knew why. mental developmental-biology pattern in mammals

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and insects’, says Ivo Große, professor of bioin- Classification into young and old multi-cellular and differentiated. The classification formatics at Martin-Luther- Universität in Halle. In their experiments, the two scientists compared into young and old was followed by comparison of the protein sequences of all 28000 genes of Ara- genetic activities of all 28000 Arabidopsis genes And what about plants? bidopsis thaliana with all adequate gene/protein in seven different embryonic stages, staring with ‘That was exactly the question we asked our- sequences of 1500 other organisms; starting with zygotes via hearts and torpedoes to mature em- selves’, says Marcel Quint. Their comprehensive bacteria, fungi and animals via algae and mosses bryos. ‘We were truly amazed by our findings’, ad- literature research about the phylotypic stage in to flowering plants Nature( 490, 2012). Similari- mits Ivo Große. What was found, as in animals, plants failed to yield results. ‘Either no-one dealt ties of corresponding genes were used to draw was that the evolutionary young genes were pur- with this problem yet or it was not deemed impor- up a phylogenetic tree of the studied organisms. posefully deactivated in the middle embryogen- tant and sunk into oblivion’, opines the 38-year- About 11000 out of 28000 Arabidopsis genes esis, in the torpedo stage, and later re-activated. old. ‘But we were fascinated by the news of the were found with high similarity in all studied spe- The old genes, in contrast, remain active through hourglass in animals. We urgently wanted to find cies: ‘We awarded to those genes the status “evo- all stages of development. out more about embryogenesis in plants.’ lutionary old”’, explains Marcel Quint. The genes This project brought the two Halle-based research- came into existence about 3.5 billion years ago, ‘We found all necessary sequencing and expres- ers together again to continue their long-standing a time long before the living world separated into sion data in publicly accessible databases of cooperation. Ivo Große, a graduate physicist and plants, fungi and animals. Those old genes in- the Scientific Community’, says Große. It took a now bioinformatician, and Marcel Quint, a gradu- clude, e.g., housekeeping genes of basal metabo- high-performance computer one week to com- ate horticulturist, holder of a doctoral degree in lism and genes that regulate replication, transcrip- pute all data – about 420 billion sequences had agronomics who is currently working as a biolo- tion and translation. to be compared to each other. The computer is gist. This fluctuation between disciplines obvious- made up of 2000 processors which are stacked ly helped them enormously to communicate with The status ‘evolutionary young’ was assigned to like pizza boxes in meter-high cubicles in the EDP each other. The efforts entailed by an interdisciplin- all other genes. Their evolution commenced 600 centre at Halle Universität. ‘An ordinary computer ary approach have paid off – and were rewarded million years ago when such plants adapted to life would have needed years’, adds the 42-year-old after 18 months of work by publication in Nature. on land which underwent true embryogenesis – bioinformatician. There was, of course, a lot of 12 back to the table of contents Cover Story

front-end work. Several gigabytes of sequence data had to be correctly downloaded from the In- ternet and validated. Databases were established, scripts written and parallelized. ‘Everybody who is making alignments knows: Alone comparison of all of two gene sequences can be problematic’, says the Berlin-born scientist. The program – ei- ther permitted to perform liberal or conservative comparisons – may show wrong positive homolo- gies or no hits although such are there. The Green Hourglass decorated the cover of the leading scientific journal Nature (4 Oc- tober 2012 Vol. 490, No. 7418). ‘We started off by reproducing Drosophila and ze- brafish data’, explains Große. ‘Then we tweaked Design: Sisters of Design GbR, Halle the parameters of the analysis pipeline to adopt it to plants. Thus, we gradually entered new ter- ritory.’ The main work was performed by two ex- cellent students, hand-picked by Große and Quint and encouraged to join the project. ‘As a result, Hajk-Georg Drost and Alexander Gabel authored to outstanding bachelor’s theses with Nature pub- lication – not a bad entry into a scientific career’, is their comment with a wink. back to the table of contents 13 Cover Story

How to interpret the data? The findings of the Halle-based researchers again med after “birth” and not dur- evidence a convergent progression of evolution. ‘Al- ing embryogenesis. ‘This is beit that embryogenesis came only into existence why we are interested to find after the separation of fauna and flora, its principle out what is happening in the – the hourglass principle – has remained the same whole plant after germination. in the two kingdoms’, says Marcel Quint. ‘What is Are old or young genes acti- unclear, though, is why evolution yielded the same vated or de-activated?’ It was result in two different ways and why the hourglass found in zebrafish that genet- was established in the first place.’ The middle em- ic activity of young and old bryonic development phase in animals is obviously genes changes again at high the phase where all important organs are forming. age, shortly before death. Mutations establish easier in young genes; hence, Young genes are de-activat- deactivation of such modifiable genes could cause ed also in this stage, while a very stringent sequence of the genetic program old genes remain active. No- and make it inaccessible for alterations. Under body knows why, and neither the strict rule of the old genes, cells are forming Professor Ivo Große (left) and Dr. Marcel Quint discover the hourglass in plants. whether the same is happen- body axes and organ combinations at appropri- Photo: Maike Glöckner (Universität Halle) ing in plants. ‘There are still ate times and in appropriate places. The structure many fascinating problems has to be complete before it is species-specific point can also explain the hourglass in plants’. Plant waiting to be solved’, the two scientists agree. and individually clad by mean of the young genes. embryos, with hypocotyl and two cotyledons, are And all this was sparked off because Karl Ernst ‘This kind of quality control could be one cause less complicated structured than animal embry- von Baer once forgot to label some jars? of the hourglass principle’, says Marcel Quint. ‘It os. In addition, the most significant plant organs, is not clear, however, whether the genetic check- such as roots, leaves and blossoms, are only for *** 14 back to the table of contents News Ticker: Research

News from science

◊ Phytohormones fling academia even after 60 years of intensive One puzzle stone research. Its effects on stretching growth, flower to our knowledge about the efficacy of auxins and other phytohormones was contributed by Luz Irina Calderón Vil- Auxin acts through a co receptor formation, fructification, aging and a variety of lalobos. Luz Irina A. Calderón Villalobos other processes make auxin a participant in al- Graph: José Andres Archila Castaño presented a comprehensive and most all plant processes of cell division and cell highly ambitious study on fine- growth. regulation of auxin efficacy at the 10th International Congress The mode of action of phytohormones has given on Plant Molecular Biology in rise over time to a notional model system, which Korea in October 2012. The is now confirmed or refuted by experimental find- results were published in co- ings. Accordingly, phytohormones are acting as operation with other scientists parts of a close-meshed signal network of many in the renowned journal Nature diverse molecular components, which interact Chemical Biology. Experimental with each other. The task at hand is to identify work supporting the paper was those components and clarify their interplay. The performed in Mark Estelle’s most interesting feature in a signal chain is always lab at University of California the first step: Binding of a hormone to its receptor in San Diego. At the IPB, Ms. and the triggered cellular reactions. Calderón Villalobos teamed up with Wolfgang Brandt and they reaped the harvest The auxin receptor was first identified in 2005Na ( - together. Auxin, the longest-known and probably ture 435, 446-451). Yet, although identification best-studied phytohormone, time and again is baf- of the receptor was deemed a milestone in auxin back to the table of contents 15 News Ticker: Research

AFB receptor and Aux/IAA repres- through combination of their two individual com- sor are located in the cell nucleus, ponents. In addition, different co receptor pairings directly on the DNA, in the regula- had different affinities to their auxin substrate. tory region of several genes that Some bound the hormone better and at lower are activated by auxin. This would concentrations than others. This – according to suggest that auxin binds to the re- the authors– could enable a staggered regulation ceptor complex and causes deg- of auxin efficacy to enable a plant to react to dif- radation of the Aux/IAA repressor. ferent stimuli both quantitatively and qualitatively. This repressor previously blocked the following genes, which are free TIRI was previously only known for its function as Three potential binding combinations of Aux/IAA repressors with TIRI re- pressors. Auxin (green) couples the two partners into a receptor complex. now and can be transcribed. And if an F-box protein, i.e. an enzyme that binds other High- or low-affinity complexes are formed, depending on the respective this were not enough: Arabidopsis proteins and thus marks them for degradation. binding partners. cells have six different TIR1 recep- The discovery that a TIRI-like F-box protein, in con- tors and, in addition, 29 variants of junction with small molecules like auxin, functions research, it was established that the found TIR1 Aux/IAA repressors. Hence, it was logical to as- as part of a receptor complex is a novel finding. receptor binds auxin at such low affinity that only sume that there is not the Auxin receptor but that And: This principle seems to be of a general na- a minor efficacy was expected. Elucidation of this combination of the two binding partners gener- ture. A similar principle of binding to a co receptor curiosity was now provided by Calderón Villalobos ates various auxin receptors which help plant cells system was recently also found for jasmonates. et al. with her contribution in Nature Chemical Biol- to react to different challenges. The authors have managed with their publication ogy. For the first time in the history of phytohor- to contribute a significant puzzle stone to the mones she was able to verify that auxin does not The authors carried out comprehensive binding overall understanding of auxin and phytohormone bind to a single receptor protein but rather func- studies, completed by 3D models of co-receptors, effects. tions as a link between two components of one and were able to verify that formation of differ- receptor complex. These two components, TIR1/ ent receptor complexes is biochemically possible *** 16 back to the table of contents News Ticker: Research

◊ Biosynthesis tobacco. Genes coding for the two enzymes were ed from clary sage (Salvia sclarea). Sage is very very elegantly isolated and characterized. Subse- sensitive to climate changes, which is why there Fragrant raw material in two steps quently, 157 different tobacco varieties were ana- is a high fluctuation of sclareol yields from year, to Biosynthesis of cis-abienol, a lyzed for presence and functional efficiency of the year which makes an impact on world market pric- constituent of Virginian tobacco two identified biosynthesis genes of cis-abienol. es. Tobacco is much more robust than sage plus (Nicotiana tabacum), has now The result: All studied varieties have biosynthesis has a higher biomass. Hence, production of an been fully elucidated. Alain Tis- genes but only 50% of the analyzed varieties are Ambrox® raw material from tobacco leaves would sier and Romy Töpfer recently capable of producing cis-abienol. be safer from fluctuations and more effective. cis- published their biochemical Abienol, however, makes up less than ten per cent genetic analyses of cis-abienol The reason for missing abienol in these plants of the dry mass of a tobacco leaf and thus it would biosynthesis in various tobacco is a mutation in one of the two synthesis genes. be desirable to breed new varieties with an in- varieties in The Plant Journal. The very comprehensive study was prompted by creased percentage of the coveted raw material. The publication, prepared in application-related aspects. cis-Abienol, a bicyclic Yet, this will only be possible with profound knowl- cooperation with French and diterpene, is a labdan-like compound whose name edge of biosynthesis and genetic constellations Swiss scientists, gives a com- is derived from labdanum, an aromatic resin that of individual tobacco varieties. If the genes were prehensive report of all aspects was produced from Mediterranean gum rockrose better known, production of cis-abienol could be of abienol synthesis in N. taba- already in ancient times. Labdan-like compounds shifted to bacteria or yeasts. The biotechnological cum which prompted the jour- are currently used as starting materials to produce production of this fragrant raw material is now at nal editors to choose it as fea- Ambrox® -- a precious fragrant that unfolds its the focus of further research projects at the IPB. tured article with a presence on the cover page. bouquet in many well-known perfumes (see p.18). According to the authors, cis-abienol is produced cis-Abienol may be the next potential starting ma- in two synthesis steps from a primary metabolism terial for semi-synthesis of Ambrox®. To date, product, geranylgeranyl pyrophosphate (GGPP), Ambrox® is predominantly produced from scla- and exclusively in glandular trichomes of Virginian reol, another labdan-like compound, that is extract- *** 17 back to the table of contents News Ticker: Research

From Ambergris to Ambrox® - The secret of Chanel and Davidoff

The Chinese took it for ‘dragon spit’ spouted out by bergris is (-)-Ambrox®. It combines, according clary sage oil which – depending on its cultivation drooling marine iguanas while sleeping on rocks. to manufacturers, a small of wet mossy forest region and climate conditions – contains a certain Egyptian merchants, on the other hand, believed soil, strong tobacco and balsamic sandalwood, percentage of sclareol. Sclareol is still produced the matter grows like mushrooms on the bottom mixed with a warm animal musk note. Already in from sage through similar extraction. Annual global of the sea and is washed ashore by occasional the ancient world, ambergris was much-coveted production of sclareol is between 50 and 150 met- storms. Only after the flourishing of the American fragrant in Arabian cultures. From the 10th cen- ric tons. Alternatively Ambrox® is produced from industry in the 18th century it could be prov- tury, matured were traded in the cis-abienol that is extracted from resin of the Ca- en beyond doubt that ambergris – that mysterious entire Mediterranean region and later all over Eu- nadian balsam fir (Abies balsamea). Several other fragrance from the sea – hails from the bowels of rope. On pound of ambergris was worth its weight semi- and total syntheses have been continually de- sperm . But it would an oversimplification to in gold or cost the equivalent of three slaves. veloped over time; however, their full-scale industri- despicably term it whale feces. Ambergris, a wax- Sperm whales are protected today under the Con- al application has failed due to low yields. One alter- like substance is produced by sperm whales as an vention on International Trade in Endangered Spe- native may be production of cis-abienol as starting antibiotic wound closure after mechanical injuries cies of Wild Fauna and Flora (CITES) and the fra- material of Ambrox® synthesis from tobacco. of their intestines. The coprolites weight up to 100 grant are semi-synthetically produced. Ambrox® is Ambrox® is the base substance for Chanel No.5® kilograms and get into the sea through excretion or found in small, albeit insufficient quantities, in Virgin- and Davidoff Cool Water®. Annual global produc- whale death. Its low density makes ambergris float ia tobacco (Nicotiana tabacum), clary sage (Salvia tion of this sought-after fragrant is slightly more on the sea surface – where the dark-gray matter sclarea), gum rockrose (Cistus labdaniferus) and than 30 metric tons. The price of one kilogram Am- with fecal odor is converted through photochemi- Mediterranean cypress (Cupressus sempervirens). brox® is ca. 1000 USD. cal degradation and oxidation into a bright-gray, The first successful semi-synthesis of Ambrox® was highly-esteemed raw material for the perfume in- made in 1950 from the diterpene sclareol (clary dustry. This process takes years to even decades. sage ). Water vapor distillation of 100 kg inflores- Source: Schäfer, B. Ambrox®. Chemie in unserer Zeit The most significant olfactory constituent of am- cence and growing tips yielded some 800 grams 2011, 45, S. 374-388. back to the table of contents 18 News Ticker: Research

◊ New Reagent Imprint:

IPB substance for one-pot synthesis The IPB Newsletter is published twice a year. Any IPB is the name of a new reagent that was de- further use of photos and contents is subject to approval by the editors. veloped by our chemists. The abbreviation stands January 2013 for 4-isocyanopermethylbutane-1,1,3-triol. This IPB, the new reagent of our chemists, stands for 4-isocy- substance belongs to the group of convertible iso- anopermethylbutane-1,1,3-triol. Editor: nitriles. IPB is capable of inserting carboxylic acid Leibniz Institute of Plant Biochemistry Weinberg 3 groups (-COOH) or amides and esters into other 06120 Halle molecules. Thus, IPB can be used in so-called one- *** Germany pot or multi-component reactions for assembling www.ipb-halle.de complex molecules. The new reagent is easier and cheaper produced than previous substances All photos by IPB, except: Hourglass (p. 12/13): Stefan Muemmler, www. of this type. It has a higher stability, dissolves bet- wissenswertes.biz ter and has a higher reactivity than its predeces- Puzzle (p. 15): José Andres Archila Castaño sor molecules. At the IPB institute, IPB is used to synthesize natural products and modified pep- German Texts: tides (protein fragments). Sylvia Pieplow English translation: inlingua®

Composition and layout: Sylvia Siersleben back to the table of contents 19