Cloning of the homeotic gene fbp2 from Petunia hybrida and its effects in tobacco flower

Messenger RNAs were isolated from the petunia ( Petunia hybrida L.) flower buds and cDNAs were synthesized from reverse transcription. The petunia homeotic gene fbp2 was amplified by PCR using cDNAs as templates. Sequence analysis indicated that the isolated fragment was composed of 686 bp and the region flanked by two primers showing 99.6% homology to the sequence reported by Angenent et at. Three bases changed, and MADS domain was conserved. Using petunia flower homeotic gene fbp2 cDNA (yfbp2) as target gene, the expression vector pBBP2 containing CaMV 35S promoter/yfbp2/nos terminator was constructed and was transformed into Agrobacterium tumefaciens strain LBA4404 (pAL4404) by direct transformation method. Incubating the leaf explants of tobacco(Nicotiana tabacum L. var, samsum) with LBA4404 (pAL4404) and selecting in the medium containing 100 mg/L kanamycin, the regenerated resistant plants were obtained. Polymerase chain reaction and Southern blotting demonstrated that the target gene was integrated into the genome of tobacco. The flowers of the transgenic tobacco were aberrant resulted in expression of fbp2, with petal formed on the stamen.