Plant Molecular Farming

The ability to precisely modify genome sequence and regulate gene expression patterns in a site-specific manner holds much promise in plant biotechnology. Genome-engineering technologies that enable such highly specific and efficient modification are advancing with unprecedented pace. Transcription activator-like effectors (TALEs) provide customizable DNA-binding modules designed to bind to any sequence of interest. Thus, TALEs have been used as a DNA targeting module fused to functional domains for a variety of targeted genomic and epigenomic modifications. TALE nucleases (TALENs) have been used with much success across eukaryotic species to edit genomes. Recently, clustered regularly interspaced palindromic repeats (CRISPRs) that are used as guide RNAs for Cas9 nuclease-specific digestion has been introduced as a highly efficient DNA-targeting platform for genome editing and regulation. Here, we review the discovery, development and limitations of TALENs and CRIPSR/Cas9 systems as genome-engineering platforms in plants. We discuss the current questions, potential improvements and the development of the next-generation genome-editing platforms with an emphasis on producing designer plants to address the needs of agriculture and basic plant biology.

To date, it was thought that mitochondria and chloroplasts were the only plant cell components able to produce chemical energy. However, according to a new article, another organelle has been identified by researchers, the chromoplast, able to synthetize energy for its metabolism.

Previously, our group engineered a plant-derived monoclonal antibody (MAb pE16) that efficiently treated West Nile virus (WNV) infection in mice. In this study, we developed a pE16 variant consisting of a single-chain variable fragment (scFv) fused to the heavy chain constant domains (CH) of human IgG (pE16scFv-CH). pE16 and pE16scFv-CH were expressed and assembled efficiently in Nicotiana benthamiana ∆XF plants, a glycosylation mutant lacking plant-specific N-glycan residues. Glycan analysis revealed that ∆XF plant-derived pE16scFv-CH (∆XFpE16scFv-CH) and pE16 (∆XFpE16) both displayed a mammalian glycosylation profile. ∆XFpE16 and ∆XFpE16scFv-CH demonstrated equivalent antigen-binding affinity and kinetics, and slightly enhanced neutralization of WNV in vitro compared with the parent mammalian cell-produced E16 (mE16). A single dose of ∆XFpE16 or ∆XFpE16scFv-CH protected mice against WNV-induced mortality even 4 days after infection at equivalent rates as mE16. This study provides a detailed tandem comparison of the expression, structure and function of a therapeutic MAb and its single-chain variant produced in glycoengineered plants. Moreover, it demonstrates the development of anti-WNV MAb therapeutic variants that are equivalent in efficacy to pE16, simpler to produce, and likely safer to use as therapeutics due to their mammalian N-glycosylation. This platform may lead to a more robust and cost-effective production of antibody-based therapeutics against WNV infection and other infectious, inflammatory or neoplastic diseases.

Leaders in Conference and Event Management and Organisation

PBVAB 2015 is the sixth meeting in this important and successful series. PBVAB 2015 will offer an international forum to review the current state of research in plant protein expression systems, down-stream processing technology, the pipeline of products now in development (including vaccines, monoclonal antibodies, and human enzymes), and efforts in using these technologies in areas beyond human health (including disease prevention in animals and aquaculture).

PBVAB 2015 will aim to attract an international audience of researchers, clinicians, and representatives for academia, industry and government/regulatory/public health organizations. Representatives for the human, veterinary, plant communities with an interest in vaccinology, immunology, biotechnology issues in relation to plant-based systems will find PBVAB 2015 of value. PBVAB 2015 will seek to develop the synergy between the human and veterinary medical/immunological/plant biotechnology communities by focusing on the immunology, vaccinology, delivery, adjuvants, and efficacy of plant based proteins.

PBVAB 2015 will aim to emphasise the take-off of the commercialisation of plant-based biologic products, the requirement for more academic based research to respond to the  question: Where is the pipeline of products going to come from and what have we learned on the decision-making processes for that product pipeline?