Genetic studies of transgenic rice plants overproducing an antibacterial peptide show that a high level of transgene expression did not cause inferior effects on host plants
Overexpression of an oat thionin gene (<i>Asthi1</i>) confers enhanced disease resistance of rice (a cultivar "Chiyohonami") against seed-transmitted phytopathogenic bacteria. The isolated paddy field test for evaluation of agronomic traits using T4 transgenic rice plants which are homozygous with a high level of Asthi1 protein has shown that transgenic rice possesses, in addition to enhanced anti-bacterial resistance, slight different characteristics compared with the original cultivar such as slight decrease in plant height, grain yield and simultaneity in heading behavior in addition to 2 days earlier in heading date. To address whether this difference was caused by ectopic high level expression of the transgene, T4 plants were back-crossed with wild-type and selfed, and the progenies were analyzed. Almost all characteristics observed in the field were found to be genetically segregated. While only a limited number of plants were used, the present findings indicate that the altered characteristics found in transgenic plants were not attributable to integration of <i>Asthi1</i> transgene or its high expression itself, but instead to possible spontaneous mutations which may have occurred during <i>in vitro</i> culture for <i>Agrobacterium</i>-mediated transformation.
- Plant biotechnology
Plant biotechnology 23(1), 63-69, 2006-03-01
Japanese Society for Plant Cell and Molecular Biology