摘要：Transgene expression from the plastid (chloroplast) genome provides unique advantages, including high levels of foreign protein accumulation, convenient transgene stacking in operons, and increased bio- safety due to exclusion of plastids from pollen transmission [1, 2]. However, applications in biotech- nology and synthetic biology are severely restricted by the very small number of plant species whose plastid genomes currently can be transformed [3, 4]. Here we report a simple method for the introduction of useful plastid transgenes into non-transformable species. The transgenes tested comprised a syn- thetic operon encoding three components of a biosynthetic pathway for producing the high-value ketocarotenoid astaxanthin in the plastids of the cigarette tobacco, Nicotiana tabacum. Transplas- tomic N. tabacum plants accumulated astaxanthin to up to 1% of the plants’ dry weight. We then used grafting, a procedure recently shown to facilitate horizontal genome transfer between plants [5–7], to let the transgenic chloroplast genome move across the graft junction from N. tabacum plants into plants of the nicotine-free tree species Nicotiana glauca. Transplastomic N. glauca trees expressing the syn- thetic pathway were recovered at high frequency, thusprovidingastraightforwardmethodforextension of the transplastomic technology to new species.