Development of an Efficient and Practical Virus-free Seedling Supply System Using Shoot Apex Culture, RT-PCR and Clonal Propagation in Sweet Potato (Ipomoea batatas) | Chapter 7 | Current Research Progress in Agricultural Sciences Vol. 10

Sweet potato (Ipomoea batatas (L.) lam.) is an important economic root crop and widely cultivated in most tropical and subtropical regions of the world. Especially in recent years, due to the explosive increase in population in African countries, sweet potatoes, a staple food, are an indispensable crop. However, the outbreak of sweet potato virus disease is not only a food crisis but also a source of regional conflicts and threatens the maintenance of peace. Considering this situation, this study aims to establish an efficient and rapid virus-free seedling production and propagation system. The study was conducted at Minami Kyushu University, Miyakonojo Campus, Japan, located at 31 degrees north latitude. At first, efficient plant regeneration was achieved from the shoot apex culture of sweet potato. Secondly, the RT-PCR method was used to detect the sweet potato feathery mottle virus (SPFMV) viral infection of the tuber surface of edible sweet potato using the RNAs from the plants obtained from shoot apex culture. Finally, the virus-free plants verified by RT-PCR were propagated clonally by the culture of suckers cut from the stems of the virus-free plants. The best efficiency for material sterilization was tested using different concentrations (0.1% - 1.5%) of sodium hypochlorite solution (SHS) and the treated times (5 min – 20 min). The shoot apexes less than 0.3mm in size were cultured on Komamine and Nomura (1998) (KN) medium and Murashige and Skoog (1962) (MS) medium. The regenerated plants were used for RNA extraction and then, used for RT-PCR for detection of SPFMV. The concentrations of RNAs were checked by electrophoresis on 2% agarose gels. Based on the result of RT-PCR, the suckers cut from stems of virus-free plants were cultured and propagated clonally and routinely within a short period. The combination of 0.3% of SHS and 10 and/or 20 min gave the best result (100%) of the surviving rate for material sterilization. The culture of shoot apexes less than 0.3 mm in size gave plant regenerating rates of 82% and 65% on KN and MS medium, respectively. The results of RT-PCR of RNAs from plants obtained from shoot apex culture and plants of SPFMV infection showed that the SPFMV virus was clearly removed by shoot apex culture conducted in this study. For clonal propagation, 80-100% of suckers cut from the stems of the virus-free plants detected grew into complete plants after 6 weeks of culture, indicating that the virus-free plants could be routinely propagated 5 times in number each time and repeatable by the short circle. The sweet potato produced in the field showed no symptom called a russet crack-like symptom (RC-LS) even after cultivation for two seasons. This study reflects an efficient and practical seedling supply system through a few steps, like using shoot apex culture to get the candidate virus-free sweet potato plants, using RT-PCR to rapidly and precisely detect the presence of SPFMV virus in the plants, and using culture of suckers cut from the tested virus-free plants to ultimately develop a clonal propagation protocol in a short period and large quantities. The study explained that an efficient, simple and practical system of virus-free seedling supply systems is urgent for the African area with the meaning of not only improved agricultural yields and food supply stability but also peace and security.

 

Author (s) Details

Lanzhuang Chen
Faculty of Environmental and Horticultural Science, Minami Kyushu University, 3764-1, Tatenocho, Miyakonojo, Miyazaki, 885-0035, Japan.

 

Chenti Xu
Qinghai Academy of Animal Science and Veterinary Medicine, Xining, Qinghai 810016, China.

 

Zhaosheng Du
Henan Academy of Agricultural Science, Zhengzhou, China.

 

Takuro Hamaguchi

Miyazaki Prefectural Office, Miyazaki, 880, Japan.

 

Toru Sugita
Miyazaki Prefecture Agricultural Experimental Station, Sadowara, Miyazaki, 880-0212, Japan.

 

Ryutarou Nagata
Miyazaki Prefecture Agricultural Experimental Station, Sadowara, Miyazaki, 880-0212, Japan.

 

Liming Guan
Faculty of Environmental and Horticultural Science, Minami Kyushu University, 3764-1, Tatenocho, Miyakonojo, Miyazaki, 885-0035, Japan.

 

Zhaosheng Du

Henan Academy of Agricultural Science, Zhengzhou, China.

 

 

Please see the book here:- https://doi.org/10.9734/bpi/crpas/v10/4893