Cultivation of endomycorrhizal fungi using Impatiens balsamina hairy roots systems

Abstract

Various methods have been employed to produce arbuscular mycorrhizal fungi (AMF) inoculants. However, substrate-based, aeroponic, or hydroponic methods are not easy to control the quality of the inoculants, while in vitro solid media-based methods cannot be scaled up. This study aimed to optimize culture conditions for AMF biomass production in liquid media using two symbiotic systems established between an AMF consortium isolated from Eleusine indica roots and hairy roots derived from purple- and orange-flowered varieties of Impatiens balsamina. The results indicated that there were different effects of the type of media, medium salt strength, phosphorus concentrations, and pH on the growth of the two symbiotic systems. The colonization rates in the resulting biomass of the two associations cultivated in liquid Murashige and Skoog with half-strength mineral nutrients, 1 mM phosphorus, and pH 5.8 were not significantly different from those of the stock inoculants. The appropriate temperature for harvesting these inoculants was 25°C, assessed through the ability to colonize and form intraradical mycorrhizal structures on new hairy roots. This was the first report of AMF production using in vitro root organ cultures in liquid medium. Cultivation conditions of this method could be easily optimized and controlled to obtain a large number of AMF inoculums.