Abstract: Transgenic rice plants were previously generated by Agrobacterium-mediated transformation during our research on molecular cloning of Xa23 gene, a bacterial blight (BB) resistance gene from the wild rice species Oryza rufipogon. To investigate the stability and inheritance of the transgene and its corresponding BB-resistance phenotype, more than 350 Xa23-trangenic rice plants from T₀, T₁, and T₂ generations were subjected to BB-pathogen inoculation, PCR and Southern blot analysis for the trans-gene. Results showed that, Xa23 gene was incorporated and expressed in the genome of the susceptible receptor rice variety Mu-danjiang 8 that acquired BB-resistance. Due to the difference of the transgene insertion sites, T₀ plants with single-copy insertion performed quite different degrees of resistance and their resistance was accurately and stably inherited to T₁ and T₂ generations. We also observed that the transgene in the single-copy insertion transgenic lines inherited following the Mendelian rules. Two homozygous, single-copy insertion transgenic lines with different resistance degrees have been obtained.

Key words: Bacterial blight, Xa23, Transgenic rice