Identification of Potato mop-top virus (PMTV) in potatoes in China

Figures & data

Fig. 1. Symptoms of Potato mop-top virus (PMTV) in potatoes collected in Huidong county in Guangdong province, China. A. Necrotic rings/arcs on tubers of potato ‘Favorita’ upon harvesting. 1, symptomatic tubers; 2, symptom-free (healthy-looking) tuber. B. Necrotic rings/arcs in flesh of tubers of potato ‘Favorita’ upon harvesting. 1, symptomatic tuber; 2, symptom-free (healthy-looking) tuber.

Fig. 2. Reverse transcription (RT)-PCR detection of Potato mop-top virus (PMTV) in potatoes collected in Guangdong province, China. A. Duplex RT-PCR for detection of PMTV and cytochrome c oxidase subunit one gene (COX1) in symptomatic tubers. B. Duplex RT-PCR for detection of PMTV and COX1 in progeny plants resulting from symptomatic tubers. The COX1 served as an internal indicator for the RT-PCR. The PMTV and COX1 primers were as reported in Xu et al. (2004) and Nie & Singh (2001), respectively. The fragment sizes were 460 bp for PMTV and 332 bp for COX1. Lanes 1 and 2, symptomatic tubers; lane 3, virus-free mini tuber (virus-free sample); lanes 4 and 5, progeny plants from symptomatic tubers; lane 6, PMTV-positive tuber, served as a positive control ; lane 7, virus-free plant.

Fig. 3. Phylogenetic tree for Potato mop-top viurs (PMTV) isolates. The partial PMTV RNA3 sequence (nucleotides 360 to 819) of PMTV isolate “Guangdong” were analyzed with the sequences of PMTV retrieved from GenBank by employing MEGA version 4.2 with the neighbor-joining (NJ) method (Tamura et al., 2007). The numbers beside branches are bootstrap values of 100 replicates.

Table 1. Detection of Potato mop-top virus (PMTV) by triple antibody sandwich enzyme-linked immunosorbent assay (ELISA)

Sample	ELISA (A405)*
Negative control	0.036
Positive control	0.170
1	0.235
2	0.233
* Sprouts from symptomatic tubers were tested with PMTV-antibody as described in the methods. The sprouts were obtained after the tubers were stored at 4^o C for 3 months. The ELISA results (A405) were means of four replicates. A sample is considered positive if the absorbance at 405 nm (A405) is equal to or greater than three times that of the negative control. The positive controls were from PMTV triple-antibody sandwich ELISA Kit provided by Neogen Europe Ltd, Adgen Phytodiagnostics. The negative controls were virus-free mini-tuber provided by Hunan Provincial Engineering Research Center for Potatoes.

Xu , H. , De Haan , T.-L. and De Boer , S.H. 2004 . Detection and confirmation of Potato mop-top virus in potatoes produced in the United States and Canada . Plant Dis , 88 : 363 – 367 .

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Nie , X. and Singh , R.P. 2001 . Differential accumulation of Potato virus A and expression of pathogenesis-related genes in resistant potato cv. Shepody upon graft inoculation . Phytopathology , 91 : 197 – 203 .

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