Plant roots are not free of microbe colonization, including by mycorrhizal fungi. Upon mycorrhizal colonization of the root system, the aboveground parts, i.e., leaves, will display increased resistance against pathogens. This beneficial microbe-induced phenomenon is called induced systemic resistance (ISR), which is distinctive from systemic acquired resistance (SAR) and occurs after a nearby leaf is infected. Recently, it was found that root colonization of orchid mycorrhizal fungi primes the plant against a necrotrophic bacterial pathogen, as is widely known in arbuscular mycorrhiza. Here, we describe a detailed method to study ISR against a bacterial pathogen (Dickeya fangzhongdai) in an orchid (Bletilla striata) primed by root colonization of mycorrhizal fungi.