Elimination of two viruses which interact synergistically from sweetpotato by shoot tip culture and cryotherapy

• Published in: Journal of virological methods 2008-12, Vol.154 (1), p.135-145
• Main Authors: Wang, Q.C., Valkonen, J.P.T.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Closteroviridae - growth & development; Cryotherapy; Fundamental and applied biological sciences. Psychology; Healthy plant production; Ipomoea batatas; Ipomoea batatas - virology; Microbiology; Plant Diseases - virology; Plants; Potyviridae; Potyviridae - growth & development; SPCSV; SPFMV; sweet potato chlorotic stunt virus; Sweet potato feathery mottle virus; Sweetpotato; Techniques used in virology; Tissue Culture Techniques; Virology; Virus localization
• ISSN: 0166-0934; 1879-0984
• DOI: 10.1016/j.jviromet.2008.08.006

Sweet potato chlorotic stunt virus (SPCSV; Closteroviridae) and Sweet potato feathery mottle virus (SPFMV; Potyviridae) interact synergistically and cause severe diseases in co-infected sweetpotato plants ( Ipomoea batatas). Sweetpotato is propagated vegetatively and virus-free planting materials are pivotal for sustainable production. Using cryotherapy, SPCSV and SPCSV were eliminated from all treated single-virus-infected and co-infected shoot tips irrespective of size (0.5–1.5 mm including 2–4 leaf primordia). While shoot tip culture also eliminated SPCSV, elimination of SPFMV failed in 90–93% of the largest shoot tips (1.5 mm) using this technique. Virus distribution to different leaf primordia and tissues within leaf primordia in the shoot apex and petioles was not altered by co-infection of the viruses in the fully virus-susceptible sweetpotato genotype used. SPFMV was immunolocalized to all types of tissues and up to the fourth-youngest leaf primordium. In contrast, SPCSV was detected only in the phloem and up to the fifth leaf primordium. Because only cells in the apical dome of the meristem and the two first leaf primordia survived cryotherapy, all data taken together could explain the results of virus elimination. The simple and efficient cryotherapy protocol developed for virus elimination can also be used for preparation of sweetpotato materials for long-term preservation.