Abstract：Medium-chain-length-polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters. The key enzyme for mcl-PHAs biosynthesis is type Ⅱ PHA synthase. The gene phaC2 encoding type Ⅱ PHA synthase was placed under the control of psbA-pro and psbA-ter of rice (Oryza sativa ) to construct phaC2 cassette, which was ligated with the screening marker gene aadA cassette (prrn-aadA-TpsbA-ter) . These recombined fragments were cloned between the plastid rbcL and accD genes for targeting to the large single copy region of chloroplast genome. Chloroplast transformation vector of pTC2 was constructed and introduced into tobacco(Nicotiana tobacum ) chloroplast genome through particle bombardment. PCR and Southern blotting analysis confirmed stable integration of phaC2 into the chloroplast genomes of T0 and T1 transgenic plants, and T1 transgenic plants exhibited homoplasmy. The expression of phaC2 at transcription level was detected by RT-PCR. Recombinant transgenes in the tobacco chloroplast genome were maternally inherited and were not transmitted via pollen when out-crossed with untransformed female plants. To our knowledge, this is the first report on the stable transformation of phaC2 encoding type Ⅱ PHA synthase in tobacco via chloroplast genetic engineering.
