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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

M4F News: Healthy Communication

Esca & Co is actually a stress conditoin - the causing fungi can live many years in the grapevine trunk without causing symptoms. When the plant is exposed to climate stress, as it happens more and more often even in our region, the fungus can sense this and kills its host. In a cooperation with the Institute for Bioactive Compounds (IBWF) in Kaiserslautern we could show that the stressed host accumulates ferulic acid, because this precursor of the wood substance lignin cannot be integrated. The fungus Neofusicoccum parvum has "learnt" to recognise ferulic acid as signal for the crisis of its host and responds bei producing Fusicoccin A, by which it drives the host into suicide, such that it can scavenge the corpse and extract the energy to generate spores for searching a new host. But what happens, when the host is healthy? Then the fungus generates 4-Hydroxyphenyl Acetic Acid, acting as growth promoter that manipulates host immunity in a way that the compound pterostilbene cannot be formed - this is the defence compound targeted against this fungus. Thus, in the absence of climate stress, the fungus might even be beneficial. Can we modulate this sophisticated chemical communication in a way that even under climate stress 4-Hydrophenyl Acetic Acid continues to be formed? This would suppress the outbreak of the disease. That is exactly what we try in frame of our project Microbes for Future (M4F) supported by the Strategic Funds of the KIT presidium. Our work on "healthy communication" has now appeared in the high-ranking journal Plant Cell & Environment:

202. Flubacher NS, Baltenweck R, Hugueney P, Fischer J, Thines E, Riemann M, Nick P, Khattab IM (2023) The fungal metabolite 4-hydroxyphenylacetic acid from Neofusicoccum parvum modulates defence responses in grapevine. Plant Cell & Environment, doi 10.1111/pce.14670 - pdf

Rice for Climate Change

Climate Change is already affecting food security. This is not only due to drought, but also other challenges, such as the increasing salinity of soils, when sea levels rise. Especially in the coastal rice production areas in Egypt, Bangladesh, or Vietnam, this has become a pertinent problem. Dr. Michael Riemann, who is heading our Plant Stress unit, investigates, therefore, which role jasmonates play in this respect, the plant version of adrenalin. He discovered, that, surprisingly, not only the formation of jasmonates, but also their decay plays an eminent role for stress resilience. For this research, especially the cooperation with Dr. Thierry Heitz at the IBMP in Strasbourg was central (funded, among others, by EUCOR), but also other partners in Germany and worldwide. Dr. Riemann has, therefore, installed the German Rice Research Network to coordinate the research on climate resilience in this central food crop. More in a broadcast by the CAMPUS-RADIO.

What is New? New Cell Type Yields Anti-Tumour Drug

The alkaloid Paclitaxel from the Pacific Yew (Taxus brevifolia) blocks the division spindle and is a crucial component of many chemotherapies against cancer. The endangered and slowly growing tree was shifted to the verge of extinction during the 1980ies. By the help of cell cultures, Phyton in Ahrensburg succeeded to supply half of the world demand. The process is lengthy and cumbersome, althoughthe cultures grow rapidly in giant steel fermenters. A cooperation project, funded by the Federal Ministry of Research, we found out, why. Paclitaxel is made only by a small fraction of cells. In those cells, cytoplasmic structure is dissolved and the interior is almost completely filled with a vacuole inside a massive membrane. We have now investigated, how the formation of this cell type is regulated and how the valuable product is secreted - not by normal exocytosis, but by fusion of so-called Multivesicular Bodies with the cell membrane.

Veröffentlichung: Manz C, Raorane ML, Maisch J, Nick P (2022) Switching Cell Fate by the Actin-Auxin Oscillator in Taxus – Cellular Aspects of Plant Cell Fermentation. Plant Cell Rep 41, 2363-2378 - pdf