A rapid sap‐direct reverse transcription‐polymerase chain reaction method for detection of dendrobium viroid in Dendrobium plants.

Dendrobium viroid (DVd) was first reported in China in 2020, and it is the only viroid known to infect Orchidaceae family plants. In this study, we developed a simple reverse transcription‐polymerase chain reaction (RT‐PCR) method for the rapid detection of DVd in Dendrobium plants. When extracting the sap template from the leaves, they are first clamped between two layers of plastic film, and the sap is pressed out and collected with a pipette. Using this sap, DVd was detected by dot‐blot and RT‐PCR methods and, the expected amplicons were confirmed by sequencing analysis. The batch analysis of field samples revealed that this method can be used to detect DVd rapidly. The detection method also reduces cross‐contamination between different samples and minimizes false positives. Thus, this sap‐direct RT‐PCR method allows effective and rapid DVd detection in the study of Orchidaceae plants. Significance and Impact of the Study: The sap‐direct reverse transcription‐polymerase chain reaction (RT‐PCR) assay described in this study is the first report of rapid detection of Dendrobiumviroid (DVd), which allows effective and rapid DVd detection in field investigations of Orchidaceaeplants. It can also be used as a reference for the detection of other plant viruses and viroids. [ABSTRACT FROM AUTHOR]