Development of highly regenerable callus lines and Agrobacterium-mediated transformation of Chinese lawngrass (Zoysia sinica Hance) with a cold inducible transcription factor, CBF1
2006
Li, R.F. | Wei, J.H. | Wang, H.Z. | He, J. | Sun, Z.Y.
Chinese lawngrass (Zoysia sinica Hance) is a warm-season turfgrass, which is widely used for golf courses, athletic fields and home lawns. In order to improve Chinese lawngrass with biotechnology, an efficient plant regeneration system was established. Five highly regenerable callus lines have been developed by addition of 6-benzylaminopurine (6-BA) and adjusting concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) in culture medium after multiple subculture, of which callus line Zh44 was used for Agrobacterium-mediated transformation. The gene, encoding C-repeat/dehydration-responsive element binding factor 1 (CBF1/DREB1b) from Arabidopsis driven by cauliflower mosaic virus (CaMV) 35S promoter, was introduced into Chinese lawngrass under selection using the bar gene with glufosinate. Three independent transgenic lines were successfully obtained using a three-step selection/regeneration procedure. The transgenic plants were confirmed by polymerase chain reaction (PCR), southern blot and reverse transcriptase polymerase chain reaction (RT-PCR) analyses. Two transgenic lines exhibited growth retardation and decreased tillering. The transgenic lines have a significantly stronger chilling tolerance than that of wild type plants, measured by ion leakage, total chlorophyll content and yellowed leaf rate in chilling conditions.
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