A novel in vitro methodology to cultivate arbuscular mycorrhizal fungi combining soil and synthetic media

Abstract

Many studies have described the potential of root organ culture (ROC) to study the biology of arbuscular mycorrhizal (AM) fungi. The dual in vitro cultivation of AM fungi and ROC permits the establishment of the mycorrhizal symbiosis and the completion of fungal life cycle by producing new and infective propagules. However, some differences in AM fungal development are evident when growing in synthetic medium versus pot microcosms or in nature. We aimed to develop a new in vitro method that allows the study of AM symbiosis in a more natural environment, but under controlled conditions. This new culture method combines an artificial growth medium and differently sterilized soil samples for the cultivation of the AM fungal species Rhizophagus intraradices and Rhizophagus aggregatus. An extensive extraradical mycelia network and abundant viable spores, with similar morphological characteristics to those obtained under pot cultures developed under this in vitro soil-based cultivation system. Formation of sporocarp-like structures by R. aggregatus was also detected for the first time using this method.