Poster: Late and Moved Abstracts

Abs # 1428: An efficient genetic transformation system for herbicide-tolerant zoysiagrass (Zoysia japonica Steud.) mediated by Agrobacterium tumefaciens

Presenter:	Lee, Hyo-Yeon , hyoyeon@cheju.ac.kr
Authors	Lee, Hyo-Yeon  (A)   Toyama, Koichi  (A)   Bae, Chang-Hyu  (B)   Kang, Joeng-Gu  (C)   Lim, Yong-Pyo  (D)   Adachi, Taiji  (E)   Riu, Key-Zung  (A)   Song, Pill-Soon  (C)
Affiliations:	(A): College of Agriculture and Life Science, Cheju National University, jeju, 690-756, Korea (B): School of Plant Production Science, Sunchon National University, Sunchon, Chonnam 540-742, Korea (C): Kumho Life and Environmental Science Laboratory, 1, Oryong-dong, Buk-gu, Kwangju 500-712, Korea (D): College of Agriculture, Chungnam National University, Taejon 305-764, Korea (E): College of Agriculture, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan

The first herbicide-resistant zoysiagrass (Zoysia japonica Steud.) has been developed by using A. tumefasiens-mediated transformation. In particular, a callus type depending-transformation system for zoysiagrass has been established by optimizing several factors that significantly affect the rate of effective Agrobacterium tumefaciens-mediated transformation, including co-cultivation period, and concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), CaCl2 and acetosyringone. A maximal GUS expression was observed when Type 3 callus was co-cultivated on a 2,4-D-free co-cultivation medium for 9 days. In addition, removal of calcium and addition of 50~100 mg/l acetosyringone during co-cultivation enhanced the GUS expression level. When this optimized protocol was applied to the transformation of bialaphos resistant gene (bar), four plants per 700 mg of infected calli successfully survived on the bialaphos-containing selection medium. A DNA gel-blot analysis for the bialaphos resistant plant confirmed the integration of two transgene copies into the zoysiagrass genome. After one week of 2 g/l bialaphos-application, the transgenic plants survived herbicide spraying, while the untransformed zoysiagrasses and invading weeds stopped growing and died. The generation of herbicide-tolerant zoysiagrass will facilitate more efficient weed control in this widely cultivated turfgrass.