Despite > 50 years of research and an increasing understanding of the potential importance of the mycorrhizal symbiosis for plant productivity, community composition and ecosystem function, we still lack a good understanding of mycorrhizal ecophysiology under field-relevant settings. This is because most research is still conducted under controlled conditions involving mycorrhizal and non-mycorrhizal plants, and with a few isolated fungal strains. While valuable, it limits our ability to have realistic expectations of the extent, and under what conditions, mycorrhizal symbioses (including recently discovered fungal symbionts, such as Mucoromycotina) can help to address threats including climate change and soil degradation worldwide. As such, methods to study in-situ mycorrhizal biology are increasingly needed.
The focus of this workshop is to bring together experts on methods that are currently being used or have the potential to be used to assess mycorrhizal ecophysiology under field-relevant conditions. These include various omics techniques (genomics, transcriptomics, metabolomics), gene editing (including CRISPR), stable and radioactive isotopes (including NanoSIMS), field manipulation techniques (e.g., tree girdling, root trenching, static and rotated cores), statistical and modelling approaches, as well as more recent innovations, such as soil chips. The goal is to exchange ideas among researchers regarding what methods can be used to approach specific questions, and to take stock of progress to date. From these discussions and post-workshop efforts, we anticipate at least one paper that outlines state-of-the-art methods to collect novel data on in-situ mycorrhizal biology, and that contrasts approaches and findings under field-relevant settings and more artificial conditions
Rational and scope
In 1982 Chiariello et al. (Science 217: 941-943) applied radioactive phosphorus (P) to leaves of one plant in an intact grassland and suggested that arbuscular mycorrhizal fungi may be involved in the P movement detected among plants. Since that seminal paper, resource flows among plants via mycorrhizal fungi have mostly been assessed under controlled conditions. The rational for this workshop is to promote more research under realistic settings. We attempt to do so by 1) highlighting tools available and 2) illustrating why such approaches are critical by contrasting number and main findings of studies conducted in-situ and ex-situ. This workshop is also timely as it builds on the successful workshop held at ICOM 12 in Manchester where the high attendance attest to the desire among researchers to not only discuss results, but also pros and cons of methods we use.
To organize the broad topic of in-situ mycorrhizal ecophysiology, we plan to separate methods targeting interactions between a) plants and mycorrhizal fungi, b) mycorrhizal fungi and other soil organisms, and c) mycorrhizal fungi and their abiotic environment. A similar separation will be used to compare ecophysiology measured ex-situ and in-situ, where available. The latter exercise will also highlight important knowledge gaps and future research directions. Lastly, the balance between early, mid-stage, and emeritus researchers across disciplines and locations will ensure a diversity of perspectives toward a common goal of assessing mycorrhizas in more complex systems.