Efficient Agrobacterium-Mediated Transformation of Hybrid Poplar Populus davidiana Dode x Populus bollena Lauche.
Poplar is a model organism for high in vitro regeneration in woody plants. We have chosen a hybrid poplar Populus davidiana Dode x Populus bollena Lauche. By optimizing the Murashige and Skoog medium with (0.3 mg/L) 6-benzylaminopurine and (0.08 mg/L) naphthaleneacetic acid, we have achieved the highest frequency (90%) for shoot regeneration from poplar leaves. It was also important to improve the transformation efficiency of poplar for genetic breeding and other applications. In this study, we found a significant improvement of the transformation frequency by controlling the leaf age. Transformation efficiency was enhanced by optimizing the Agrobacterium concentration (OD(600) = 0.8-1.0) and an infection time (20-30 min). According to transmission electron microscopy observations, there were more Agrobacterium invasions in the 30-day-old leaf explants than in 60-day-old and 90-day-old explants. Using the green fluorescent protein (GFP) marker, the expression of MD-GFP fusion proteins in the leaf, shoot, and root of hybrid poplar P. davidiana Dode x Populus. bollena Lauche was visualized for confirmation of transgene integration. Southern and Northern blot analysis also showed the integration of T-DNA into the genome and gene expression of transgenic plants. Our results suggest that younger leaves had higher transformation efficiency (~30%) than older leaves (10%).
Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC),  Northeast Forestry University, Harbin Hexing Road, Harbin 150040, China. shenkuiliu@nefu.edu.cn.
Xue
X
Han
Shurong
S
Ma
Xianghui
X
Kong
Tetsuo
T
Takano
Shenkui
S
Liu