Genetic Identification of functions of TL-DNA transcripts in octopine crown galls.

The TL-DNA in octopine crown galls encodes seven transcripts most, if not all, expressed from individual promoters. Site-specific deletions and substitutions in the T-region of the octopine plasmid pTiB6S3 indicate some of the functions of the TL-DNA transcripts. Two of the seven genes are sufficient to allow tumorous growth. T-DNA transfer and oncogenicity are controlled by different and independently acting functions. None of the transcripts of TL-DNA appear to be essential for T-DNA transfer. Four, possibly five, of the TL-DNA transcripts act by suppressing organ development. Shoot and root formation are suppressed by the action of different transcripts.