SOMACLONAL VARIATION IN TRANSGENIC PLANTS

Abstract

This paper summarises our experience of the molecular and field analysis of somaclonal variation within transgenic plant populations. Transgenic rice, poplar and sugarcane plants were produced with different transformation protocols. These were based on protoplast treatment, Agrobacterium tumefaciens infection, particle acceleration or intact cell electroporation, all having in common dedifferentiated cell culture, followed by plant regeneration and selection. Transgenic Arabidopsis thaliana plants have also been produced by an approach that apparently does not require cell dedifferentiation. This is based on in planta Agrobacterium-mediated gene transfer by infiltration of adult Arabidopsis thaliana plants. The presence and activity of the foreign gene in the transgenic genonie has been verified by conventional methods (PCR, Southern. Northern and Western blotting). Genomic changes have been evaluated with PCR-based tools (RFLP. RAPD, AFLP, RAMP and AFRP). The statistical analysis of the polymorphic DNA bands produced by these tools provided the basis for answering some basic questions related to the conditions that favour induction, frequency, inheritance and commercial exploitation of transgenic somaclonal variants.