Structural organization of str 246C and str 246N, plant defense-related genes from Nicotiana tabacum.

We have previously identified a cDNA clone, pNt246, whose corresponding transcripts accumulate in leaves in response to inoculation by compatible and incompatible isolates of the phytopathogenic bacterium Pseudomonas solanacearum [19]. We now describe the nucleotide sequence of a genomic clone, str 246C, corresponding to this cDNA species, and of a related genomic clone, str 246N, which appears to be a pseudogene with a 5'-end deletion. The nucleotide sequence of the str 246C gene was found to be identical to that of the parA gene, previously shown to be regulated by auxin [28, 29]. Upstream of the str 246N gene, sequences homologous to a Bam HI repetitive element described in Vicia faba [15] are present within an ORF showing significant homologies to an integrase-encoding gene of several retroviruses. This observation indicates that this highly repetitive DNA originates from sequences present in transposable mobile elements.