Su, Yi ChenYi ChenSuHuang, Pung LingPung LingHuangYI-YIN DO2023-04-182023-04-182023-01-0109717811https://scholars.lib.ntu.edu.tw/handle/123456789/630240Avian influenza is a disease of poultry that causes economic losses to poultry farms. Conventional vaccine production requires chicken embryos for virus proliferation with time-consuming and also affected by egg supply during the avian influenza virus outbreak. There are several advantages of plant cells as bio-factories for vaccine production, including low cost, low risk of contamination, and even edible. In this study, we chose carrot (Daucus carota) as a bioreactor to produce hemagglutinin (HA), an avian influenza virus antigen protein. HA gene linked with heat-labile enterotoxin B subunit (LTB) gene whose product plays the role of adjuvant protein was codon optimized with codon usage bias of carrot for high-level expression. The native and codon-optimized LTB–HA were transformed into carrots by Agrobacterium-mediated transformation. T-DNA insertion of two version constructs was confirmed by polymerase chain reaction. Integration of codon-optimized LTB–HA gene in all transgenic carrot lines was identified as a single copy by Southern blot analysis. LTB–HA protein expressed in carrot cells was determined through enzyme-linked immunoassay. Codon-optimized LTB–HA gene showed a better expression level than the native LTB–HA gene in transgenic carrots. The highest expression level of LTB–HA in codon-optimized LTB–HA-transformed carrot taproot reached up to 0.0108% of total soluble protein. This study is the first report about expression of HA antigen of H5N2 subtype AIV in a horticultural crop. Our transgenic carrots have successfully produced HA protein which shows great potential to become an edible vaccine against avian influenza virus.Agrobacterium-mediated transformation | Codon-optimization | Plant-based oral vaccine | Production of recombinant protein[SDGs]SDG3journal article10.1007/s13562-023-00840-62-s2.0-85151428080https://api.elsevier.com/content/abstract/scopus_id/85151428080