In vitro cultures open new prospects for basic research in arbuscular mycorrhizas

Abstract

It is now 20 years since the publication of Bécard and Fortin's article (1988) in which the modern basis for arbuscular mycorrhizal (AM) monoxenic cultures was established. Since then, many research projects have been carried out using in vitro systems, and new prospects have been opened up by utilizing the amazing research material provided by monoxenic plates. More and more researchers now acknowledge that in vitro AM production is the sole way of getting large amounts of clean, clonal, contamination-free AM fungal material. This has opened the doors for molecular biology and biochemical techniques to be applied to mycorrhizal research, and the direct consequence of this is an exponential increase in our knowledge in the basic biology of this mutualistic symbiosis over the last 10 years. However, monoxenic cultures have far more to offer than just being AM tissue factories; fields of AM research as different (yet interlinked) as colony architecture and dynamics, intra- and extraradical fungal morphology, mycorrhizal physiology, biotic and abiotic stress responses, microbial interactions and even the production of ultrapure, mycorrhiza-based biofertilizers have benefited from this 'in vitro revolution'. This chapter aims to summarize the opportunities offered by using in vitro culture technology, and to encourage researchers to (1) utilize existing, yet little known monoxenic culture techniques, and (2) improve them and design new in vitro experimental systems. It should not be regarded as a compilation of methods, but rather as a brainstorming exercise designed to create new avenues of mycorrhizal research.