A reverse transcription loop-mediated isothermal amplification assay for the detection of citrus exocortis viroid in Australian citrus

Abstract Citrus exocortis viroid (CEVd), the causal agent of exocortis, is a pathogen that thought to infect all citrus varieties, although it asymptomatic in most. Symptoms develop on susceptible rootstocks, resulting stunting and yield reduction. To aid detection management CEVd, rapid near-field assay was developed using reverse transcription loop-mediated isothermal amplification (RT-LAMP) for viroids nursery field trees. Over 240 CEVd sequences, including sequence variants from representative Australian isolates induce mild severe symptoms, were used design primers. The RT-LAMP successfully detected 1:1000 dilution (236 pg) plant total RNA indicating high sensitivity, also rapid, crude extractions. highly specific given there no cross-reactivity with other citrus-infecting pathogens. This new provides simple, robust, specific, sensitive method detect our knowledge, first any viroid.