Comparison of Methods for Virus Detection in Allium spp.

Reverse transcriptase (RT)-polymerase chain reaction (PCR) and immunocapture (IC)-RT-PCR protocols were developed and optimized for the sensitive detection of Onion yellow dwarf virus, Leek yellow stripe virus and allexiviruses infecting Allium species. Polyvalence of the designed primers was successfully demonstrated, using samples of di€erent plant species and geographic origins. Di€erent sample preparation procedures were evaluated for their suitability to provide appropriate PCR tem- plates. IC-PCR, RT-PCR with plant tissue extracts, and RT-PCR with total RNA, proved to be 102±104 times more sensitive than double-antibody sandwich-enzyme- linked immunosorbent assay (ELISA). Furthermore, a `one stepʹ IC-RT-PCR assay was developed using plant leaf extract as template source, which proved to be 102 times more sensitive than ELISA, and convenient for testing large numbers of leaf samples.