Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) belong to the group of microbial polyesters. The key enzyme for mcl-PHA 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 a 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 the chloroplast genome. A chloroplast transformation vector, pTC2, was constructed and introduced into the tobacco (Nicotiana tobacum) chloroplast genome by particle bombardment. PCR and Southern blot 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 reverse transcriptase–polymerase chain reaction (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.

A length polymorphism in the trnL/trnF intergenic spacer was used as a marker to determine the mode of chloroplast inheritance in Streptocarpus (Gesneriaceae). Exclusively maternal inheritance was recorded for all the F1 progeny of reciprocal intraspecific crosses between S. primulifolius and a population referred to as S. aff. primulifolius from the Igoda River mouth, Eastern Cape, South Africa, and for interspecific crosses between S. rexii and S. dunnii. A combination of molecular and morphological data was used to clarify the origin of S. aff. primulifolius, which possesses S. rexii-type cpDNA and rDNA, while the morphological data suggest an intermediate position between S. rexii and S. primulifolius. The distribution of S. rexii and S. primulifolius, combined with molecular and morphological data, supports the hypothesis that the S. aff. primulifolius population is a hybrid between S. rexii and S. primulifolius, with S. rexii as the maternal parent, and that substantial molecular but limited morphological introgression into S. primulifolius has taken place.