Submitted to: Microbiology China
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2012
Publication Date: 2/20/2013
Citation: Bao, G., Zuo, R., Rao, W., Li, R., Li, F. 2013. Detection of sweet potato viruses in Yunnan and genetic diversity analysis of the common viruses. Microbiology China. 40(2):236-248. Interpretive Summary: Sweet potato is an important staple food in Yunnan Province, China. Propagation of the crop by cuttings allows the accumulation and spread of transmissible pathogens. Diseases of sweet potato have been a serious problem for years in this province, but little is known about the pathogens. In this study, symptomatic samples were collected from 16 sweet potato production regions and tested for 8 important viruses infecting sweet potato. Results showed that virus infections were common in most regions, and three potyviruses which are part of a serious disease complex were predominant. Molecular analysis also showed that different genetic types existed for each of the three viruses. The study indicates that viruses are associated with sweet potato production problems in Yunnan Province. This information will be used to stress the importance of using clean propagation materials to farmers, as well as to develop better strategies for sustainable sweet potato production.
Technical Abstract: Two hundred seventy-nine samples with virus-like symptoms collected from 16 regions in Yunnan Province were tested by RT-PCR/PCR using virus-specific primers for 8 sweet potato viruses. Six viruses, Sweet potato chlorotic fleck virus (SPCFV), Sweet Potato feathery mottle virus (SPFMV), Sweet potato leaf curl virus (SPLCV), Sweet potato virus C (SPVC), Sweet potato virus G (SPVG) and Sweet potato virus 2 (SPV2), were detected in 123 samples (44.1%) from 14 regions. Of all the detected viruses, SPVG was detected in 109 samples (39.1%), SPFMV in 75 samples (26.9%), SPVC in 69 samples (24.7%), SPCFV in two samples (0.7%), and SPLCV in one samples (0.4%). Mixed infections of 2-5 viruses were common (31.9%). The RT-PCR amplicons of SPFMV, SPVC and SPVG from selected samples were cloned and sequenced. Sequenced analysis showed that the Yunnan isolates of SPFMV belonged to three strains, EA strain, O strain, and a novel strain. The SPVC isolates were divided into three subgroups, and SPVG Yunnan isolates were divided into two subgroups, with the majority in subgroup I.