Full Length Research Paper

Studies on Agrobacterium-mediated genetic transformation of embryogenic suspension cultures of sweet potato

Yu-Jun Xing^1,2, Qin Ji¹*, Qing Yang², Yu-Ming Luo¹, Qiang Li³ and Xin Wang³

¹Department of Biology, Huaiyin Teachers College , Huaian , Jiangsu 223300, P.R. China.

²College of Life Sciences, Nanjing Agricultural University, Nanjing Jiangsu 210095, P.R. China..

³Sweet Potato Research Institute, Chinese Academy of Agricultural Science, Xuzhou, Jiangsu 221121, China.

*Corresponding author. E-mail: jiqin@hytc.edu.cn, Tel: 86-517-3525382, Fax: 86-517-3525992.

Abbreviations: 2,4-D, 2,4-dichlorophenoxyacetic acid; ABA, abscisic acid; AS, acetosyringone; Cefo, cefotaxime; GA, gibberellic acid; Kan, kanamycin; MS, Murashige and Skoog; NPT II, neomycin phosphotransferase; PCR, polymerase chain reaction; SBD, starch-binding domain.

Accepted 23 January, 2008

In this study, genetic transformation of embryogenic suspension cultures of sweet potato (Ipomoea batatas) cultivar Xu55-2 was conducted utilizing the Agrobacterium tumefaciens strain EHA105 that contains the binary vector pBIN19/SBD2 with SBD2 (starch binding domain 2) gene and neomycin phosphotransferase (NPT II) gene. The presence of the SBD2 gene in the genomic DNA of transgenic plants was verified by PCR amplification and confirmed by Southern blot analysis. Results suggested that cefotaxime (Cefo), at the concentration of 200 mg/L, was able to effectively suppress the growth of Agrobacterium after co-cultivation. The optimal concentration for kanamycin (Kan) was 10 mg/L for selecting resistance calli, somatic embryo formation and plant regeneration. The highest frequency of shoot induction (30.9%) was obtained on the MS medium containing 10 mg/L Kan, 200 mg/L Cefo, 1.0 mg/L abscisic acid (ABA) and 1.0 mg/L gibberellic acid (GA₃).

Key words: Ipomoea batatas, Agrobacterium-mediated transformation, SBD2 gene, embryogenesis.