From the Root Chip to the Bioherbicide

Plants have sly old ears. An estimated million compounds occur only in plants and have the task to convince other life forms to do work for plants. Often, cellular signalling is hijacked. We humans are no exception – whether it is caffeine, opium, or Cannabis, specific plant compounds play tricks to our neural system. One particular weird case of plant manipulation could now be uncovered. Our Mints beat competitors by a „Deathly After Eight“. Why does this not damage the sender himself – here the compounds are most abundant? Using Spearmint as paradigm, we could demonstrate that the scent, carvone, persuades root cells of the target to dissolve its microtubules and initiate a ritual form of suicide. Changing minute details on fhte molecule eliminates this effect. Thus, carvone is not a poison, but a persuasive signal. Obviously, this signal can bind to a specific receptor that otherwise has the task to ward off microbial attacks. In that context, cellular suicide makes perfectly sense. By its sacrifice, the infected cell kills the intruder and protects the others. We suspect that Mints have modified their own receptor, such that carvone cannot bind. Signals that eliminate competitors – this has, of course, considerable potential for the development of novel bioherbicides. In the next step we want to find out, who listens to the signal and identify the receptor. Schritt wollen wir nun herausfinden, wer auf dieses Signal hört. This sophisticated strategy could be uncovered by our project DialogProTec (Science Offensive of Interreg Upper Rhine) during an interdisciplinary cooperation with partners at the Campus North IMT, Université de Strasbourg, the Institute for Biological Agents in Kaiserslautern, the University of Freiburg, and the Research Institute for biological Agriculture in Frick and publish in the Journal of Experimental Botany.

Publication

210. Hering N, Schmit AC, Herzog E, Corbin LT, Schmidt-Speicher L, Ahrens R, Fauconnier ML, Nick P (2024) Spearmint Targets Microtubules by (−)-Carvone. Hort Res. doi.org/10.1093/hr/uhae151 - pdf

The Origin of Grapevine

Four years of hard work, almost 4000 genomes - the fruit of this effort has now been published in Science. The Wild Grapevine Collection of the KIT had an important role here. It could be shown that Grapevine was domesticated twice independently, once in the Caucasus to produce wine, a second time in the Near East to get table grapes. During its migration to the West, there were numerous love affairs with local wild grapevines, giving rise to the large diversity of grapevines. This project joined people from 16 countries, despite sometimes difficult political circumstances and allows a deep look into the complex history of this crop plant that not only founded civilisations, but was also one of the first globally traded goods, breaching the borders of geography, language, and religion. The treasure of knowledge generated in this project has not even been scratched - during the time, when grapevine, by an interplay between climatic disruptions and human migration, conquered many regions, it collected genes that help to cope with adverse conditions. These genes can help now to safeguard viticulture against the consequences of climate change - this is exactly, what we do now in our Interreg Upper Rhine project Kliwiresse. Seminar as part of the Saturday University Freiburg.

Science article

Interview with the Washington Post

Press release by the KIT

Youtube on the impact of the project for the region

How Can Plants Distinguish Stress Qualities?

Plants cannot run away, when they do not like their environment. They need to adapt. The ability to recognise and to appropriately respond to challenges is, thus, the central strategy for plant survival. We need to understand this as to prepare for climate change. Meanwhile, this has reached public consciousness. However, it is mostly unclear, how plant distinguish stress qualities. When different stresses act in concert, they even have to render decisions. This happens, for instance, during a hot summer day  - shall the leaves be cooled by transpiration, or shall the water rather be saved up to get through an ensuing drought? How can plants decide without a brain? For us, this world is so strange that we do not understand it. Here, our new concept starts - in brief, we propose that there are a handful of signals that mean, by recombination, different qualities of stress and, therefore, evoke different responses. Actually quite comparable to human language - the "words" are these signalling molecules, the "grammar" is their temporal sequence and combination. Using concrete examples we demonstrate that this idea works and develop its evolutionary context. While this concept may appear unusual, it leads to clear implications that can be tested experimentally, and it yields explanations to explain the complex stress responses of plants.

Publication

[63] Nick P (2023) Towards a Grammar of Plant Stress – Modular Signalling Conveys Meaning. Theor Exp Plant Physiol. doi 10.1007/s40626-023-00292-2 - pdf

Genetic Barcodes Crack Forensic Enigma

Since many years, we work on methods to unveil fake and surrogation of plant-based food, but also medicinal products using so-called DNA barcods. Our taxonomically carefully identified and developed collection of reference plants in the JKIP Experimental Station at the Adenauerring has been crucial to this work. Our work is often thematised in the media, just recently in a broadcast of the Hessische Rundfunk on Superfood that was then also shown by NDR, WDR, ARD and MDR (see video...). This echo has induced interest from those institutions that in Germany are in charge of food safety. Here, we obtained, in the middle of the Corona period, an unusual request by the Chemical Veterinary Investigation Office in Freiburg - they had to deal with several cases of animal poisoning, whether we could support them? We could - using a combination of microscopic diagnostics and DNA barcoding we could solve all cases. The usual method, where species are assigned through a statistic value of sequence similarity, was refined for this purpose. We used (statistically ignored) specific sequence motifs as genetic fingerprints - this approach is known in evolution research as homology by specific quality. This forensic study has now been published in PloS ONE:

204. Schweikle S, Häser A, Wetters S, Raisin M, Greiner M, Fischer U, Pietsch K, Suntz M, Nick P (2023) DNA barcoding as new diagnostic tool to lethal plant poisoning in herbivorous mammals. PloS ONE 18, e0292275 - pdf

INTERVIEW IN THE CAMPUS RADIO

Salty Wine

An often neglected consequece of climate change is the increase of soil salinity - rising sea levels, but also artificial irrigation make more and more soild go lost. A joint project funded by the German and the Tunisian Ministry of Science investigated this for grapevine. During a comparative study, we could show that a wild grapevine that had been found in the Atlas mountains, can grow even under severe salinity, although it takes up the salt and transfers it to the leaves. Together with the Max-Rubner Institute we can show that the metabolic processes in the leaves are tuned in a more robust manner, such that the accumulation of dangerous reactive oxygen species can be avoided. This allows the wild grapevine to assign its resources preferentially for photosynthesis. Thus, there is not a miracle molecule of resilience, resilience rather appears to be a more efficiently orchestrated connection of different metabolic processes. This work has now appeared in the high ranking journal Plant Physiology .

Publication:

199. Daldoul S, Gargouri M, Weinert C, Jarrar A, Egert B, Mliki A, Nick P (2023) A Tunisian Wild Grape Leads to Metabolic Fingerprints of Salt Tolerance. Plant Physiology - pdf

Press release of the KIT

What is New? Cells Need Competence

In biotechnology, cells are often called "biomass". This sounds a bit as if the nature of the cell does not matter, as long as the right gene is introduced by genetic engineering. In the real world, the individuality of the producing cell is crucial. This can be shown for medicinally relevant plant compounds that are often produced in a "team work" of several cell types, whereby each cell type drives a different, specific, chemical reaction. We have addressed this point using Catharanthus roseus, a medicinal plant from Madagascar, where we try to reconstruct the synthesis of the anti-tumour compound vincristine in cell cultures. Around 200 kg leaf material is needed for 1 mg, which makes this compound very expensive. Since the 1960ies people have tried to generate this compound in cell culture, in vain. We suspected that this different cell types need to cooperate, as it is the case in real plant tissues. In cooperatoin with the company Phyton from Ahrensburg we searched for different cell types and found two strains, Cat1 and Cat4, that activate different branches of the metabolism that are mutually exclusive and even suppressive. These cells are endowed with a quite different metabolic competence. However, when we were feeding the Cat4 cells with the precursor made from the Cat1 cells and activated defence metabolism by the stress hormone jasmonic acid, we were able, for the first time, to detect vincristine and to demonstrate by mass spectroscopy that it was really vincristine. The amounts are still very low, unfortunately, but this work shows that it is principally possible, if one more seriously considers the diversity and individuality of plant cells and their differential metabolic competence.

Publication

190. Raorane ML, Manz C, Hildebrandt S, Mielke M, Thieme A, Keller J, Bunzel M, Nick P (2023) Cell type matters: competence for alkaloid metabolism differs in two seed-derived cell strains of Catharanthus roseus. Protoplasma 260, 349-369 - pdf

What is New?  Bioherbicide from Mint

We need plant protection, but our herbicides challenge the environment, poison the groundwater, and cause collateral damage to harmless or even beneficial organisms. We need more specificity. This is possible - all living beings use numerous signals to influence others for their own sake. Can we use this? That is what we did: Mints are very competitive and smell quite differently, depending on the species. We found that these scents are signals, by which they persuade other plants into suicide. For Horsemint we have investigated this in detail and developed on the base of this knowledge an application, by which we can suppress Bindweed, a pertinent problem in organic cereal production.

Publication:

195. Sarheed M, Schärer HJ, Wang-Müller QY, Flury P, Maes C, Genva M, Fauconnier ML, Nick P (2023) Signal, not poison – Horsemint essential oil for weed control. Agriculture 13, 712 - pdf