Transformation of Lotus japonicus using the herbicide resistance bar gene as a selectable marker

Transgenic plants of the model legume Lotus japonicus were regenerated by h ypocotyl transformation using a bar gene as a selectable marker. The bar en codes for Phosphinothricin Acetyl Transferase that detoxifies phosphinothri cin (PPT), the active ingredient of herbicides such as Ignite (AgrEvo) and Basta (Hoechst). Transgenic L. japonicus plants resistant to PPT were posit ive upon PCR by bar gene-specific primers. In 5 out of 7 independent lines tested, PPT resistance segregated as a single dominant allele indicating a single T-DNA insertion into the plant genome. All regenerated plants were f ertile and void of visible somaclonal abnormalities contrary to 14% inferti lity when antibiotic selectable markers were used. The lack of somaclonal v ariation, ease of PPT application and low cost of PPT makes this protocol a n attractive alternative for the regeneration of transgenic L. japonicus. T he production of PPT herbicide-resistant L. japonicus plants may have signi ficant commercial applications in crop production.