Optimising expression and extraction of recombinant proteins in plants

Recombinant proteins are of paramount importance for research, industrial and medical use. Numerous expression chassis are available for recombinant protein production, and while bacterial and mammalian cell cultures are the most widely used, recent developments have positioned transgenic plant chassis as viable and often preferential options. Plant chassis are easily maintained at low cost, are hugely scalable, and capable of producing large quantities of protein bearing complex post-translational modification. Several protein targets, including antibodies and vaccines against human disease, have been successfully produced in plants, highlighting the significant potential of plant chassis. The aim of this review is to act as a guide to producing recombinant protein in plants, discussing recent progress in the field and summarising the factors that must be considered when utilising plants as recombinant protein expression systems, with a focus on optimising recombinant protein expression at the genetic level, and the subsequent extraction and purification of target proteins, which can lead to substantial improvements in protein stability, yield and purity.

Duckweed: a potential phytosensor for heavy metals

Globally, heavy metal (HM) contamination is one of the primary causes of environmental pollution leading to decreased quality of life for those affected. In particular, HM contamination in groundwater poses a serious risk to human health and the potential for destabilization of aquatic ecosystems. At present, strategies to remove HM contamination from wastewater are inefficient, costly, laborious, and often the removal poses as much risk to the environment as the initial contamination. Phytoremediation, plant-based removal of contaminants from soil or water, has long been viewed as an economical and sustainable solution to remove toxic metals from the environment. However, to date, phytoremediation has demonstrated limited successes despite a large volume of literature supporting its potential. A key aspect for achieving robust and meaningful phytoremediation is the selection of a plant species that is well suited to the task. For the removal of pollutants from wastewater, hydrophytes, like duckweed, exhibit significant potential due to their rapid growth on nutrient-rich water, ease of collection, and ability to survive in various ecosystems. As a model for ecotoxicity studies, duckweed is an ideal candidate, as it is easy to cultivate under controlled and even sterile conditions, and the rapid growth enables multi-generational studies. Similarly, recent advances in the genetic engineering and genome-editing of duckweed will enable the transition from fundamental ecotoxicity studies to engineered solutions for phytoremediation of HMs. This review will provide insight into the suitability of duckweeds for phytoremediation of HMs and strategies for engineering next-generation duckweed to provide real-world environmental solutions.

Wolffia arrhiza as a promising producer of recombinant hirudin

The production of recombinant proteins in transgenic plants is becoming an increasingly serious alternative to classical biopharming methods as knowledge about this process grows. Wolffia arrhiza, an aquatic plant unique in its anatomy, is a promising expression system that can grow in submerged culture in bioreactors. In our study 8550 explants were subjected to Agrobacterium-mediated transformation, and 41 independent hygromycin-resistant Wolffia lines were obtained, with the transformation efficiency of 0.48%. 40 of them contained the hirudin-1 gene (codon-optimized for expression in plants) and were independent lines of nuclear-transformed Wolffia, the transgenic insertion has been confirmed by PCR and Southern blot analysis. We have analyzed the accumulation of the target protein and its expression has been proven in three transgenic lines. The maximum accumulation of recombinant hirudin was 0.02% of the total soluble protein, which corresponds to 775.5 ± 111.9 ng g^-1 of fresh weight of the plant. The results will be used in research on the development of an expression system based on Wolffia plants for the production of hirudin and other recombinant pharmaceutical proteins.

Research Progress of a Potential Bioreactor: Duckweed

Recently, plant bioreactors have flourished into an exciting area of synthetic biology because of their product safety, inexpensive production cost, and easy scale-up. Duckweed is the smallest and fastest-growing aquatic plant, and has advantages including simple processing and the ability to grow high biomass in smaller areas. Therefore, duckweed could be used as a new potential bioreactor for biological products such as vaccines, antibodies, pharmaceutical proteins, and industrial enzymes. Duckweed has made a breakthrough in biosynthesis as a chassis plant and is being utilized for the production of plenty of biological products or bio-derivatives with multiple uses and high values. This review summarizes the latest progress on genetic background, genetic transformation system, and bioreactor development of duckweed, and provides insights for further exploration and application of duckweed.