Polyvalent detection of twelve viruses and four viroids affecting tomato by using a unique polyprobe

Abstract

[EN] Non-radioactive molecular hybridization represents an attractive approach for the detection of multiple plant virus and/or viroids and a good alternative to the more extended serological and PCR-based detection methods. The use of polyprobes or riboprobes carrying partial sequences of different plant viruses or viroids fused in tandem, has permitted the detection of up to 10 different pathogens or the development of genus-specific probes. In the present article, the polyprobe technology has been adapted for the detection of the main viruses and viroids affecting tomato crops. To do this, three polyprobes have been developed covering four viroids (Poly4), twelve viruses (Poly12) or the four viroids plus the twelve viruses (poly16). The detection limit of the three polyprobes was comparable to the individual probes allowing the detection of up to 0,2 pg/mu l of viral or viroidal RNA. A survey of 50 field samples revealed that all positive samples detected with the individual probes were also detected with the corresponding poly12 (98%) or poly16 (100%) probes. The analysis of tomato seeds revealed that both, single and polyprobes, were able to detect an infected seed in a pool of 250 healthy seeds. Finally, a ring-test analysis among six laboratories revealed a high reproducibility of the non-radioactive molecular hybridization procedure using the three polyprobes. The use of this technology in the routine analysis of tomato samples is discussed.