Page 252 - PC2019 Program & Proceedings

PLANT CANADA 2019

P77. Expression of malaria antigens in the chloroplast of Chlamydomonas reinhardtii; the first step
towards developing malaria algae-based oral vaccine candidates
*1
Shamriz, S. ; H. Ofoghi 2
1 University of Western Ontario
2 Iranian Research Organization for Science and Technology

Among all recombinant platforms, microbes are the most common systems for the production of
commercially valuable products. Over the past decades, transgenic plants have attracted much attention
because of both cost and safety matters. To take the advantage of both microbes and plants, microalgae-
based platforms have been developed as a cost-effective and easily scalable alternative, possessing the
positive features of both plants and microorganisms.
Malaria is still a serious disease threatening the lives of millions of people annually. So, any effort to
reduce the burden of malaria is of utmost significance. This project aims to exploit the potential of
Chlamydomonas reinhardtii chloroplast in expressing malaria antigens as a first step towards developing
malaria algae-based oral vaccine candidates. C. reinhardtii chloroplast is capable of folding complex
proteins while lacking the ability to glycosylate proteins; a remarkable feature since the Plasmodium
parasite has not N-linked glycosylation machinery.
Fusion constructs consisting of antigen and adjuvant were designed and analyzed computationally.
Transplastomic C. reinhardtii expressing the verified construct were produced and transgene integration
and homoplasmicity were confirmed. Recombinant products were assessed by western blotting and
ELISA tests. Results obtained demonstrated that expressed recombinant proteins accumulate as a soluble
and properly folded protein within algal chloroplasts. Future work includes animal immunization both
through oral administration and by injection to assess immune responses to the designed vaccine
candidate.

Shabnam Shamriz (sshamriz@uwo.ca)

P78. The effects of nutrient solution pH on protein expression and morphology of Agrobacterium-
infiltrated Nicotiana benthamiana in hydroponic growth conditions
Bennett, L.
Univeristy of Guelph

The integration of vertical farming technology into plant based production of therapeutic proteins,
monoclonal antibodies and vaccines has the potential to significantly improve plant productivity and
target expression efficiency. Trastuzumab, an immunoglobulin G monoclonal antibody (IgG1), is used in
the treatment of HER2-positive breast cancer and is successfully produced in Nicotiana benthamiana in
greenhouse production using peat-based substrates. In order to better understand how to transition to
vertical production using soilless hydroponic culture, this project focuses on composition and plant
uptake of nutrient solution ions in hydroponic growth conditions. The pH of a solution directly affects
nutrient availability for plants. By changing the pH of a solution, nutrients can become more readily
available for plant uptake, and therefore may influence morphological growth and protein expression in
plants. Results of a case study in which five groups of 12 N. benthamiana plants were grown using
nutrient film technique (NFT) hydroponics at five different levels of pH: (1) 5.0, (2) 5.5, (3) 6.0, (4) 6.5
and (5) 7.0 is discussed. Genes encoding the heavy and light chains of trastuzumab were introduced into
the plants at five weeks from the time of transplant using Agrobacterium tumefaciens through vacuum
infiltration. Results from plant morphological measurements and protein expression found that a
relatively wide pH range of 5 -6.5 yielded the best results for IgG1expression (mg/kg).

Lauren Bennett (lbenne08@uoguelph.ca)

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