A perennial plant with vibrant colourful flowers from Northern Asia, Aster tataricus is known for its several medicinal applications, such as the treatment of infections of the respiratory highways. A big part of these medicinal properties has been attributed to astins, which are complex, chlorinated molecules found in this plant. Just recently, it has been discovered that Cyanodermella asteris, an endophytic fungus of this plant, is what (at least to an extent) synthesizes these valuable compounds, making this plant-endophyte interaction an interesting system for the scientific community.
Despite the scientific interest, working with the A. tataricus-C. asteris system remains challenging as the plant is dormant during the winter and is quite large. For this reason, Professor Ludwig-Mueller and her team at TU Dresden searched for a feasible plant-endophyte system that allowed them to efficiently study the C. asteris- plant interaction. Interestingly, the researchers observed that all the screened plants --sunflower, Chinese cabbage, rapeseed, tomato, and Arabidopsis thaliana --displayed a similar altered growth phenotype when co-cultivated with C. asteris, including shorter main roots, increased lateral root growth, and higher aerial biomass, indicating that the fungus can beneficially influence plants from different families.
Further characterization of the C. asteris-A. thaliana interaction revealed very interesting aspects of the molecular dialogue between these organisms. “We showed that in plant-microbe interactions the microbe not only influences the plant but also vice versa. C. asteris induced massive lateral root growth in A. thaliana , leading to higher biomass and healthier plants. To accomplish this, the fungus not only used soluble compounds, like the phytohormone indole-3-acetic acid or the fungal secondary metabolite astin C, but also volatiles, among them carbon dioxide,” said first author Linda Jahn.
“On the other hand, we observed that the addition of plant hormones to fungal cultures of C. asteris also influenced the microorganism. For instance, the addition of auxins to the media led to increased fungal growth, whereas jasmonic acid increased the production of the fungal metabolite astin C. We could also show that this metabolite, which is known as an anti-tumoral compound, influences plant growth; so, here we describe a two-side interaction of a fungus with a non-natural host,” added the researcher.
Ludwig-Mueller and her team are currently investigating which genes might be triggered in A. thaliana in the interaction with C. asteris to understand if the fungus is acting as an endophyte or more like a pathogen.
“Understanding the interaction between C. asteris and its plant host might promote the development of a reproducible biosystem of astin (or other valuable bioactive compounds) production for medical use,” she concluded.
For more information about this study, read The Endophytic Fungus Cyanodermella asteris Influences Growth of the Nonnatural Host Plant Arabidopsis thaliana in the MPMI Journal.
Molecular Plant-Microbe Interactions
Experimental study
Not applicable
The Endophytic Fungus Cyanodermella asteris Influences Growth of the Nonnatural Host Plant Arabidopsis thaliana
23-Jan-2022