Purslane (Portulaca oleracea L.) as a novel green-bioreactor for expression of human serum albumin (HSA) gene.

Transgenic plants showed high potential to become a valuable and safe source of bio-compounds that can be used as therapeutics without any require for pooled human blood products. Human serum albumin (HSA) is one of the best-selling pharmaceuticals in the world because it is utilized for treating several acute illnesses, including hypovolemia, burns, and hemorrhage. This work was aimed to investigate the production of recombinant HSA (rHSA) protein in a plant-based expression platform. For this, we used in-planta and tissue culture-based Agrobacterium-mediated transformation (TCBAT) procedures to insert HSA gene into purslane (Portulaca oleracea L.) genome. The purslane seeds and leaves were infected with A. tumefaciens strain LBA4404 containing the HSA gene on pBI121 plasmid, and then regenerated into transgenic plant on MS medium. The qRT-PCR, southern hybridization, western blotting, and ELISA analysis were accomplished to corroborate the insertion and expression of HSA gene in transgenic plantlets. The molecular asses indicated that HSA gene was successfully transferred and expressed in purslane plants using in-planta and TCBAT methods. The first attempt to express rHSA in purslane resulted in a low-level accumulation of the protein in the transgenic plant shoots. Therefore, we used a synthetic 5'UTR (synJ) to enhance HSA transcript stability and translation efficiency. The results suggested that the synJ caused pronounced enhancement of rHSA expression rate. The highest amount of rHSA protein was recorded in transgenic purslane generated by TCBAT method (33.92 ± 4.31 µg/g FW).