Abstract
Mimosa pudica rapidly folds its leaves when exposed to various external stimuli, such as mechanical, thermal and electrical stimulations. Although the mechanism of this unique leaf movement has attracted wide attention of botanists for centuries, molecular and genetic studies have been hampered by the lack of gene manipulation system. Here we report methods for reproducible plant regeneration and Agrobacterium-mediated transformation to generate stable genetic transformants. First, we determined the conditions for shoot and root induction. The highest frequency of shoot regeneration was observed when the cotyledons were cultured on half-strength MS medium containing appropriate NAA and BAP ratios. The regenerated shoots successfully rooted on half-strength Hoagland's medium. Secondly, we optimized transformation conditions. The highest transformation efficiency was obtained under the conditions in which the cotyledons scratched with a knife and the hypocotyls were sonicated, and subsequently transfected by A. tumefaciens strain LBA4404 harboring a super binary vector pSB111. These results serve as a basis for establishing an effective transformation system in M. pudica.
