Chloroplast-Selective Gene Delivery in Mature Plants Using Carbon Nanotube Nanocarriers

Plant genetic engineering is an important tool used in current efforts in crop improvement, pharmaceutical product biosynthesis and sustainable agriculture. However, conventional genetic engineering techniques are primarily limited to the use of biolistic device or PEG-mediated transformation, the efficiency of which is highly species- and tissue-dependent. In this work, we rationally designed chitosan-complexed single-walled carbon nanotubes, utilizing an experimentally-verified mechanism to safely and selectively deliver genetic materials into the chloroplasts of mature plants. This nanoparticle-mediated delivery does not require external chemical or mechanical aid which often leads to significant damage to the plant tissue. We demonstrate chloroplast-targeted transgene delivery and transient expression in mature Eruca sativa, Nasturtium officinale, Nicotiana tabacum and Spinacia oleracea plants and in isolated Arabidopsis thaliana mesophyll protoplasts. Our work provides practical advantages over current delivery techniques as a potential species-independent transformation method to benefit plant bioengineering and biological studies.