The identification of fungal endophytes often relies on culturing isolates from surface-sterilized plant tissue. However, molecular techniques have enabled the rapid detection and identification of targeted endophyte species, and next-generation sequencing technology provides an opportunity to obtain comprehensive information on endophytic communities, directly from plant tissue. In order to achieve accurate detection from internal tissues, surface microbes and associated deoxyribonucleic acid (DNA) must be eliminated, with particular consideration for the type of plant tissue and the efficacy of the surface sterilization procedure used. The methodology described later was developed specifically for detection of DNA from the entomopathogenic fungal endophyte Beauveria bassiana (Vuillemin) (Ascomycota: Hypocreales) in various tissues of Zea mays (L.). However, the protocol may be easily applied to other fungi and bacterial endophytes. Included is a stringent sodium hypochlorite-based surface sterilization protocol for plant material in preparation for polymerase chain reaction (PCR) to detect target DNA within plant tissue. Included are a treatment for dealing with surface DNA contamination and a novel procedure for assessing the efficacy of surface sterilization using PCR.
Keywords: Biocontrol; DNA isolation; Entomopathogenic fungal endophyte; Next-generation sequencing; PCR; Propidium monoazide; Surface sterilization.