Sustainable access of quality seeds of genetically engineered crops in Eastern Africa - Case study of Bt Cotton.

The genetically engineered bollworm-resistant Bt cotton hybrid varieties offer opportunities for reducing crop losses and enhancing productivity. In Eastern Africa region, Sudan, Ethiopia, and Kenya have approved and released Bt cotton in 2012, in 2018, and in 2019, respectively. The region has potential to grow cotton in over 5 million hectares. For commercial plantings in Ethiopia, Sudan and Kenya, hybrid Bt cotton seeds have been imported from India. Due to the COVID-19 pandemic-induced supply chain disruptions, high shipment costs, bureaucratic procedures for importing seeds, and foreign exchange shortages, farmers have not been able to access Bt cotton seeds. Stakeholders are seeking local production of seeds to provide sustainable access by farmers at affordable cost. Country case studies reveal the importance of enhancing capacity for local seed production and extension advisory services. Revival of the cotton sector needs enhanced public-private partnerships to pave the way for sustainable seeds access in the region.

CRISPR/Cas Genome Editing Technologies for Plant Improvement against Biotic and Abiotic Stresses: Advances, Limitations, and Future Perspectives.

Crossbreeding, mutation breeding, and traditional transgenic breeding take much time to improve desirable characters/traits. CRISPR/Cas-mediated genome editing (GE) is a game-changing tool that can create variation in desired traits, such as biotic and abiotic resistance, increase quality and yield in less time with easy applications, high efficiency, and low cost in producing the targeted edits for rapid improvement of crop plants. Plant pathogens and the severe environment cause considerable crop losses worldwide. GE approaches have emerged and opened new doors for breeding multiple-resistance crop varieties. Here, we have summarized recent advances in CRISPR/Cas-mediated GE for resistance against biotic and abiotic stresses in a crop molecular breeding program that includes the modification and improvement of genes response to biotic stresses induced by fungus, virus, and bacterial pathogens. We also discussed in depth the application of CRISPR/Cas for abiotic stresses (herbicide, drought, heat, and cold) in plants. In addition, we discussed the limitations and future challenges faced by breeders using GE tools for crop improvement and suggested directions for future improvements in GE for agricultural applications, providing novel ideas to create super cultivars with broad resistance to biotic and abiotic stress.

Plant-Derived Human Vaccines: Recent Developments.

The idea of producing vaccines in plants originated in the late 1980s. Initially, it was contemplated that this notion could facilitate the concept of edible vaccines, making them more cost effective and easily accessible. Initial studies on edible vaccines focussed on the use of a variety of different transgenic plant host species for the production of vaccine antigens. However, adequate expression levels of antigens, the difficulties predicted with administration of consistent doses, and regulatory rules required for growth of transgenic plants gave way to the development of vaccine candidates that could be purified and administered parenterally. The field has subsequently advanced with improved expression techniques including a shift from using transgenic to transient expression of antigens, refinement of purification protocols, a deeper understanding of the biological processes and a wealth of evidence of immunogenicity and efficacy of plant-produced vaccine candidates, all contributing to the successful practice of what is now known as biopharming or plant molecular farming. The establishment of this technology has resulted in the development of many different types of vaccine candidates including subunit vaccines and various different types of nanoparticle vaccines targeting a wide variety of bacterial and viral diseases. This has brought further acceptance of plants as a suitable platform for vaccine production and in this review, we discuss the most recent advances in the production of vaccines in plants for human use.

Molecular farming using transgenic rice endosperm.

Plant expression platforms are low-cost, scalable, safe, and environmentally friendly systems for the production of recombinant proteins and bioactive metabolites. Rice (Oryza sativa L.) endosperm is an ideal bioreactor for the production and storage of high-value active substances, including pharmaceutical proteins, oral vaccines, vitamins, and nutraceuticals such as flavonoids and carotenoids. Here, we explore the use of molecular farming from producing medicines to developing functional food crops (biofortification). We review recent progress in producing pharmaceutical proteins and bioactive substances in rice endosperm and compare this platform with other plant expression systems. We describe how rice endosperm could be modified to design metabolic pathways and express and store stable products and discuss the factors restricting the commercialization of transgenic rice products and future prospects.

Applications of Genomic Tools in Plant Breeding: Crop Biofortification.

Crop breeding has mainly been focused on increasing productivity, either directly or by decreasing the losses caused by biotic and abiotic stresses (that is, incorporating resistance to diseases and enhancing tolerance to adverse conditions, respectively). Quite the opposite, little attention has been paid to improve the nutritional value of crops. It has not been until recently that crop biofortification has become an objective within breeding programs, through either conventional methods or genetic engineering. There are many steps along this long path, from the initial evaluation of germplasm for the content of nutrients and health-promoting compounds to the development of biofortified varieties, with the available and future genomic tools assisting scientists and breeders in reaching their objectives as well as speeding up the process. This review offers a compendium of the genomic technologies used to explore and create biodiversity, to associate the traits of interest to the genome, and to transfer the genomic regions responsible for the desirable characteristics into potential new varieties. Finally, a glimpse of future perspectives and challenges in this emerging area is offered by taking the present scenario and the slow progress of the regulatory framework as the starting point.

Plant-derived VLP: a worthy platform to produce vaccine against SARS-CoV-2.

After its emergence in late 2019 SARS-CoV-2 was declared a pandemic by the World Health Organization on 11 March 2020 and has claimed more than 2.8 million lives. There has been a massive global effort to develop vaccines against SARS-CoV-2 and the rapid and low cost production of large quantities of vaccine is urgently needed to ensure adequate supply to both developed and developing countries. Virus-like particles (VLPs) are composed of viral antigens that self-assemble into structures that mimic the structure of native viruses but lack the viral genome. Thus they are not only a safer alternative to attenuated or inactivated vaccines but are also able to induce potent cellular and humoral immune responses and can be manufactured recombinantly in expression systems that do not require viral replication. VLPs have successfully been produced in bacteria, yeast, insect and mammalian cell cultures, each production platform with its own advantages and limitations. Plants offer a number of advantages in one production platform, including proper eukaryotic protein modification and assembly, increased safety, low cost, high scalability as well as rapid production speed, a critical factor needed to control outbreaks of potential pandemics. Plant-based VLP-based viral vaccines currently in clinical trials include, amongst others, Hepatitis B virus, Influenza virus and SARS-CoV-2 vaccines. Here we discuss the importance of plants as a next generation expression system for the fast, scalable and low cost production of VLP-based vaccines.

Next biotechnological plants for addressing global challenges: The contribution of transgenesis and new breeding techniques.

The aim of this survey is to identify and characterize new products in plant biotechnology since 2015, especially in relation to the advent of New Breeding Techniques (NBTs) such as gene editing based on the CRISPR-Cas system. Transgenic (gene transfer or gene silencing) and gene edited traits which are approved or marketed in at least one country, or which have a non-regulated status in the USA, are collected, as well as related patents worldwide. In addition, to shed light on potential innovation for Africa, field trials on the continent are examined. The compiled data are classified in application categories, including agronomic improvements, industrial use and medical use, namely production of recombinant therapeutic molecules or vaccines (including against Covid-19). The data indicate that gene editing appears to be an effective complement to 'classical' transgenesis, the use of which is not declining, rather than a replacement, a trend also observed in the patenting landscape. Nevertheless, increased use of gene editing is apparent. Compared to transgenesis, gene editing has increased the proportion of some crop species and decreased others amongst approved, non-regulated or marketed products. A similar differential trend is observed for breeding traits. Gene editing has also favored the emergence of new private companies. China, and prevalently its public sector, overwhelmingly dominates the patenting landscape, but not the approved/marketed one, which is dominated by the USA. The data point in the direction that regulatory environments will favor or discourage innovation.

Antiviral Activity of Ribosome-Inactivating Proteins.

Ribosome-inactivating proteins (RIPs) are rRNA N-glycosylases from plants (EC 3.2.2.22) that inactivate ribosomes thus inhibiting protein synthesis. The antiviral properties of RIPs have been investigated for more than four decades. However, interest in these proteins is rising due to the emergence of infectious diseases caused by new viruses and the difficulty in treating viral infections. On the other hand, there is a growing need to control crop diseases without resorting to the use of phytosanitary products which are very harmful to the environment and in this respect, RIPs have been shown as a promising tool that can be used to obtain transgenic plants resistant to viruses. The way in which RIPs exert their antiviral effect continues to be the subject of intense research and several mechanisms of action have been proposed. The purpose of this review is to examine the research studies that deal with this matter, placing special emphasis on the most recent findings.