Molecular changes in protoplast-derived rice plants.

To determine whether regeneration of rice plants from protoplast culture induces DNA polymorphisms, progeny plants from direct regenerants of such cultures were examined for restriction fragment length polymorphisms (RFLP analysis). Significantly increased levels of DNA polymorphism were found compared with those in non-tissue culture control plants. Analysis with gene sequences representative of different functional domains, revealed that such polymorphisms are apparently widespread and not associated with any particular region. Analysis by comparative digestion with both methylation-sensitive and insensitive restriction enzymes revealed that methylation changes cannot be regarded as a major factor in the induction of these DNA polymorphisms.