Vegetative propagation of seed potato often allows passaging of viruses to seed tubers, resulting in significant yield losses and reduction of potato tuber quality.  Thus, virus detection approach is crucial for effective virus management programs and the production of virus-free seed potatoes.  Among the reported potato-infecting viruses, potato virus A (PVA) is considered as one of the most important viruses in potato-growing regions worldwide.  This study prepared four hybridoma lines secreting PVA-specific monoclonal antibodies (MAbs) (2D4, 8E11, 14A6 and 16H10) using purified PVA virions as an immunogen.  Western blotting results indicated that all the four MAbs reacted strongly and specifically with the putative capsid protein of PVA.  Using these four MAbs, this study developed antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA), Dot-ELISA and Tissue print-ELISA for detection of PVA infection in potato plants.  The results indicated that PVA can be detected in crude tissue extracts from infected potato plants diluted up to 1:327 680 (w/v, g mL^–1) by ACP-ELISA or up to 1:10 240 by Dot-ELISA.  The Tissue print-ELISA is the quickest and easiest approach among the three serological assays, and is more suitable for onsite large-scale potato screening programs.  Further analyses of field-collected potato samples showed that the sensitivities and specificities of the three serological approaches were similar to those of RT-PCR in PVA detection and confirmed that PVA is currently widespread in Yunnan and Zhejiang provinces of China.  Hence, the results strongly suggest that these highly sensitive serological approaches based on PVA-specific MAbs are useful and powerful for PVA-free seed potato production programs and PVA field surveys. 

Potato virus M (PVM) is one of the common and economically important potato viruses in potato-growing regions worldwide.  To investigate and control this viral disease, efficient and specific detection techniques are needed.  In this study, PVM virions were purified from infected potato plants and used as the immunogen to produce hybridomas secreting PVM-specific monoclonal antibodies (MAbs).  Four highly specific and sensitive murine MAbs, i.e., 1E1, 2A5, 8A1 and 17G8 were prepared through a conventional hybridoma technology.  Using these four MAbs, we have developed an antigen-coated plate (ACP)-ELISA, a dot-ELISA and a Tissue print-ELISA for detecting PVM infection in potato plants and tubers.  PVM could be detected in infected potato plant tissue crude extracts diluted at 1:10 240 (w/v, g mL^–1) by the dot-ELISA or at 1:163 840 (w/v, g mL^–1) by the ACP-ELISA.  The Tissue print-ELISA is the quickest and easiest assay among the three established serological assays and is more suitable for onsite large-scale sample detection.  Detection results of the field-collected samples showed that PVM is currently widespread in the Yunnan and the Heilongjiang provinces in China.  The field sample test results of the developed serological assays were supported by the results from RT-PCR and DNA sequencing.  We consider that the newly established ACP-ELISA, dot-ELISA and Tissue print-ELISA can benefit PVM detection in potato plant and tuber samples and field epidemiological studies of PVM.  These assays can also facilitate the production of virus-free seed potatoes and breeding for PVM-resistant potato cultivars, leading to the successful prevention of this potato viral disease.