Insertional mutagenesis in Arabidopsis thaliana: Presonication of germinating seeds increases the efficiency of their transformation

An efficient procedure of transforming Arabidopsis thaliana germinating see ds was elaborated on the basis of the method of Feldmann and Marks. The pro cedure involves microdamaging TI seeds by sonication before culturing with a vector Agrobacterium strain and yields more than 1% T2 transformants. Ger minating seeds were transformed with Agrobacterium tumefaciens hypervirulen t strain A281 carrying plasmid pLD3 derived from pBI121. A collection of 54 A. thaliana T2 transformants was obtained; some of them showed marked morp hological alterations. The transgenic nature of plants that acquired resist ance to a marker antibiotic was confirmed histochemically and by PCR amplif ication of a T-DNA region.