Agricultural biotechnology. A growing field.

Abstract

BioTechniquesVol. 37, No. 3 Technology NewsOpen AccessAgricultural BiotechnologyLynne LedermanLynne LedermanSearch for more papers by this authorPublished Online:6 Jun 2018https://doi.org/10.2144/04373TN01AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInRedditEmail A Growing FieldAgriculture, a human activity for many thousands of years, provides us with food, raw materials for clothing and building, and a multitude of other commodities. Agriculture is practiced world-wide, but in distinctly different forms in different parts of the world. In developed countries, where applications of biotechnology to agriculture have had an increasing impact, the debate over genetically modified crops has affected both their acceptance and trade. In other parts of the world, however, where a significant proportion of the population is malnourished and is plagued by theoretically preventable diseases, the debate may center more on the necessity of importing technology versus using local resources, than on the actual nature of that technology itself. Agricultural biotechnology may be able to address the lack of arable land by increasing plant productivity, increasing the nutritional content of food crops to meet the specific nutritional deficiencies of particular populations, and improving crop resistance to drought, salinity, pests, and diseases.Technician making tissue culture (TC) banana plants in Kenya.Provided by S. Wakhusama, International Service for the Acquisition of Agri-Biotech Applications Africenter, NairobiThe theme of the recent NABC16, the sixteenth annual conference sponsored by the National Agricultural Biotechnology Council and held at the University of Guelph, Ontario, Canada, was “Agricultural Biotechnology: Finding Common International Goals.” According to Alan Wildeman, VP of research at the university and chair of the conference, an important outcome of the meeting, which centered on the challenges of diminishing the ecological footprint, improving quality of life, and ensuring safe and healthy food, was that biotechnology can and should be put into the context of these goals. Focusing on them can make a difference to a large portion of humanity, he notes, and requires taking a global perspective. He added that “biotechnology will play a very important role in the future, and this will be most evident when it addresses goals that are in common to everyone.”Improving CropsOne agricultural success story that relies on what has long been a standard laboratory technique is the tissue culture (TC) banana. Bananas, a staple in many countries, are susceptible to a variety of diseases. In many areas, farmers have no choice but to use infected suckers to propagate bananas. The mass production of virus-free plants through the use of tissue culture has resulted in crops with an earlier maturing time, larger bunch weight, and higher annual yields per unit of land than conventionally produced crops.The use of TC banana stock has not solved all of the problems afflicting this crop. The incorporation of trans-genes may be the solution to overcoming some of the nonviral diseases to which this plant is subject, as well as to increasing the nutritional value of the fruit. The dominant traits that have been modified to date in the four current commercial genetically modified (GM) crops, soybeans, corn (maize), cotton, and canola, have been herbicide tolerance and insect resistance. Increasing the nutritional content of internationally significant food crops such as cassava, maize, sorghum, millet, and rice, will be an important goal of agricultural bio-technology.Production PlantsIn 1993 at a vaccines conference at Cold Spring Harbor Laboratories, the most exciting and well-received presentation predicted the expression in an edible fruit, e.g., the banana, of as many as 10 different antigenic proteins. The goal was an inexpensive, multivalent oral vaccine for developing countries that would be easy to produce, ship, and administer. The plan was to introduce each gene, under the control of a promoter for ripening genes, into separate plants, cross-breeding them to obtain recombinants. At the time, it seemed like this development was just around the corner. Eleven years later, creation of transgenic plants to express immunogenic proteins as well as other proteins of therapeutic interest is coming into its own, at least as a production system if not the end product, where political, biologic, and regulatory issues remain to be addressed. Plant-based production systems have advantages over mammalian cell-based systems. They are free of human pathogens, less labor- and skill-intensive, and inexpensive.“The concept of producing vaccines in plants is a good one,” says Kenneth Rosenthal, Northeastern Ohio Universities College of Medicine, Rootstown, OH. “Plants can make a lot of protein.” Practical questions that need to be answered for whole-plant vaccines are: (i) do they taste good; (ii) can they be eaten raw to avoid heat denaturation; (iii) is the protein expressed in the edible portion of the plant; (iv) would the material be amenable to lyophilization or other processing to create a food supplement; (v) is the product heat stable; and (vi) are the antigens delivered efficiently and effectively across the gastrointestinal mucosa?Pharma-Planta, a consortium, of 39 laboratories in 11 European countries with input from South African researchers, is being formed to produce vaccines and other therapeutics that would be of greatest benefit to developing countries. The first product may be an antibody that could be used as a microbicide in a vaginal cream to block transmission of human immunodeficiency virus (HIV), and the second a post-exposure vaccine for rabies. Tuberculosis is another likely target. The first clinical trials are anticipated to begin in 2009. Candidate plants to use for production include tobacco, maize, potatoes, and tomatoes, with anticipation that expression of high levels of the desired proteins in easily harvested seeds will facilitate manufacture of the final product. Phillip Dale, John Innes Centre, Norwich, UK, notes that the plants would be grown on dedicated land isolated from food crops, and creation of sterile male lines that do not produce pollen would be used as a strategy to isolate these plants genetically from food crops.At Arizona State University, Hugh S. Mason's laboratory is investigating the use of some of the same plants, as well as alfalfa, to produce in edible plant tissues vaccines to viruses including hepatitis B, and to enteropathogenic Escherichia coli. Hepatitis B virus (HBV) is also a target of Akira Yano's group at the National Institute of Public Health, Tokyo, and colleagues at Tokai University School of Medicine, Isehara, Japan. They are expressing recombinant monoclonal antibodies (MAbs) to HBV in tobacco suspension cultures rather than in intact plants. The MAbs thus produced appear to show complement-depen-dent cytotoxicity against HBV surface antigen (HBsAg) similar to that of the anti-HBsAg immunoglobulins that are currently being used clinically and that must be purified from the blood of HBV-immune donors. The MAbs produced in plants have the potential to replace the blood-derived antibodies and eliminate the risk of infectious agents that might be present in the blood-derived product. Plant MAbs will be an inexpensive and potentially effective alternative when various technical problems can be solved, as Yano expects should happen in the next few years.Transgenic tobacco cells producing hepatitis B virus surface antigen (HBsAg) monoclonal antibodies (MAbs).Provided by Akira Yano, National Institute of Public Health, TokyoSequence BuzzThe honey bee is about to join the select group of organisms whose genome has been completely sequenced. According to J. Spencer Johnston, at Texas A&M University, College Station, TX, the sequencing, funded by the National Institutes of Health (NIH), is nearly complete, although gaps in the assembly of the sequences remain to be filled. The Baylor Human Genome Sequencing Center has created bacterial artificial chromosome (BAC) clones as part of the honey bee sequencing efforts, and fluorescent in situ hybridization (FISH) is being used to anchor these chromosomes to sequence and map data. Dan Weaver, along with Johnston a member of the Honey Bee Genome Sequencing Consortium, predicts that the annotated sequence, as well as a comparison with the anticipated sequence of Africanized honey bees, will eventually result in the ability to obtain bees that are less defensive, polli-nate more efficiently, and produce more honey.Johnston says, “Pollination behavior is one area that has not progressed much with classic selection techniques.” One of his personal concerns is to be able to identify potentially dangerous bee colonies. “Up to a fifth of the bee genes are likely to be either unique to bees,” he believes, “or will be so different that they are not easily recognized in other genomes.” These include genes associated with olfaction, social behavior, and eyesight. The honey bee, a social insect with a brain half the size of that of a fruit fly, uses symbolic language to communicate with its fellow hive members. “Is it likely that genes involved in social behavior will be found in the bee first, then secondarily be found to be a part of the human genetic social scene? I'd bet on it,” says Johnston. The honey bee genome is simple compared with that of humans, except for the complex of genes involved in social interaction. It is this complex, he notes, “that is best studied with honey bee microarrays and expressed sequence tag (EST) libraries defining that complete system.”The 16 DAPI-stained meiotic metaphase chromosomes of the haploid honey bee drone. Red, position of a honey bee bacterial artificial chromosome (BAC) clone.Courtesy of J. Spencer Johnston and the Baylor Human Genome Sequencing CenterFuture ProspectsThe first generation biotechnology products for agriculture have been driven by both research and profit, notes Edilberto Redona of the Philippine Rice Research Institute. To ensure future relevancy, acceptance, and benefits to the populations who most need all that agricultural bio-technology can offer, he suggests a bottom-up approach that takes into account the social and agricultural practices of the target market and focuses on the areas that will have the greatest impact, namely increasing productivity and quality.FiguresReferencesRelatedDetails Vol. 37, No. 3 Follow us on social media for the latest updates Metrics Downloaded 197 times History Published online 6 June 2018 Published in print September 2004 Information© 2004 Author(s)PDF download