Phosphorous, this important and essential mineral, is part of our DNA and, therefore, irreplaceable. Many soils are already depleted for phosphorous and plants growing on them are only able to take up enough phosphorous by living in symbiosis with arbuscular mycorrhizal fungi (AM fungi). This symbiosis is a non-synchronous process, which means that different cells in the root can show different phases of symbiotic interaction with the fungus. For this reason, the scientists used laser capture microdissection to excise single root cells and deciphered their specific gene activity.
When scientists are analysing the molecular composition of plant cells they usually assume that different cells from the same tissue are alike. In many cases, this assumption is true. The majority of cells from leaves, stems or roots show similar levels of gene expression and metabolic activity. It gets more complicated when plants undergo symbiosis, because interactions with the symbiotic partner may alter the cell’s metabolism. And even cells adjacent to colonised cells that have not yet come into direct contact with the fungus can show drastic changes in their gene expression levels.
The most prevalent plant symbiosis is that between root cells and arbuscular mycorrhizal fungi, called AM fungi. AM fungi make sure that plants can grow on nutrient-depleted soil – unnoticed by most people. These fungi outstretch their filamentary cells, called hyphae, far into the soil and are thereby able to take up more nutrients than plants can absorb with their roots. The fungus takes up mainly phosphate, but possibly also nitrate and metal ions like copper, zinc and iron and gives these willingly to the plant. In return, it is rewarded with sugars that plants produce via photosynthesis.
Interestingly, fungus and plant cell never really merge; they are constantly separated by membranes, the outer boundaries of the cells. To enable the relatively big sugar and phosphate molecules to pass through these membranes, the plant cells insert big protein complexes that resemble tunnels through which the molecules can freely travel from one cell to another. This was already known, and it was not astounding that the scientists around Franziska Krajinski found genes that encode for such transport proteins to be highly expressed in cells that are already colonised by the fungus. A more surprising discovery was, however, that even cells that are in close vicinity of the colonised cells seemed to be already reprogrammed. More than 800 genes showed enhanced activity exclusively in these cells. “The higher transcription rate of genes that are responsible for transport proteins, lipid acid metabolism and gene regulation does not seem to be a result of the colonisation by the fungus,” explains Nicole Gaude, first author of the study. “It is more likely that cells are preparing themselves for an imminent colonisation by the fungus.”
These very precise and specific results were obtained with the help of laser capture microdissection. In this method, a laser beam is used to excise individual cells from a tissue. At least 5000 cells were cut out by Gaude and her team; a time-consuming manual labour that even Sisyphus would have been proud of. But the time and effort were worth it. “We now know which genes are activated even before a symbiosis is physically established,” explains Gaude.
Understanding the symbiotic programme of plants could enable the use of AM fungi in agriculture and reduce the application of expensive, artificial fertilizer in the future.
ContactNicole Gaude/Franziska Krajinski
The Plant Journal, Advanced Online Publication 06 October, DOI: 10.1111/j.1365-313X.2011.04810.x
Ursula Ross-Stitt | Max-Planck-Institut
Funding of Collaborative Research Center developing nanomaterials for cancer immunotherapy extended
28.06.2017 | Johannes Gutenberg-Universität Mainz
Zeolite catalysts pave the road to decentral chemical processes Confined space increases reactivity
28.06.2017 | Technische Universität München
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
28.06.2017 | Physics and Astronomy
28.06.2017 | Physics and Astronomy
28.06.2017 | Health and Medicine