The importance of biosafety in the deployment of private transgenic sorghums in the environment
Microorganisms Branch Biotechnology, Biologics, and Environment Protection USDA/APHIS/BBEP, 4700 River Rd, Unit 147. Riverdale, MD 20737, USA
Code Number: CS95018 Size of Files: Text: 8.2K No associated graphics files
This pa per provides a n overview of the concerns towards commercialization and deployment of transgenic sorghums. It also highlights the key role USDA/APHIS has played in the international harmonization of biotechnology regulatory policies.
Key Words: Commercialization, transgenic sorghums, regulatory policies
Ce papier donne un apercu sur les problemes lies a la commercialisation et la diffusion des sorgho transgeniques. I1 met aussi en evidence le role cle de I'USDA/APHIS dans l'harmonisation des politiques reglementant la biotechnologie.
Mots Cles: Commercialisation, sorgho transgeniques, politiques regulatoires
Biosafety and environmental impacts of introducing genetically engineered organisms into different agricultural environments present new challenges for the commercialization of biotechnology products. For an environmentally sound and sustainable mode of agricultural development, it is essential that biosafety issues be examined in detail to allay fears of significant impacts to non-target organisms, and also any other potential changes in the agriculture of crop plants, and related health and social structure effects. Biosafety has become a critical issue for technology transfer of safe products of biotechnology.
The USDA/Animal and Plant Health Inspection Service (APHIS) has been at the forefront of international harmonization of biotechnology regulatory policies, and has actively promoted the development of protocols to safely deploy genetically engineered plants in different agroclimatic conditions. To that end, APHIS/ Biotechnology, Biologies, and Environmental Protection (BBEP) has sponsored half a dozen biosafety workshops on maize, wheat, tomato, potato, canola, and rice. These workshops have been of immense value, and serve as useful guides to most countries worldwide.
Current sorghum (Sorghum bicolor (L.) Moench) breeding efforts are directed at several agronomic traits, most important of which is the resistance to the parasitic weed Striga. Several biotechnological efforts are underway to engineer weed controlling traits into sorghum.
Recently, a group of researchers at Purdue University, West Lafayette, Indiana, USA, through funding from Pioneer Hi-Bred International, reported the first successful transformation of sorghum with a bar gene from Streptomyces hygroscopicus. that confers tolerance to the herbicide bialaphos (Casas et al., 1993). The bar gene codes for phosphinothricin acetyl transferase. the enzyme that detoxifies glufosinate. the ammonium salt of phosphinothricin. This is a significant development in the area of agricultural biotechnology, sorghum being an important grain and forage crop that is uniquely adapted to semi-arid environments dominant in most of the tropical countries of the world.
Sorghum is a coarse grain, which is a staple food for more than 400 million people in the semi-arid tropics and has been grown in Africa for more than 6000 years (Doggert, 1988). The crop ranks second to rice as the most important staple food of the people of the tropics. Sorghum occupies fifth place in the world production of crops (59 million metric tonnes from 45 million hectares of land). In the western hemisphere, sorghum is primarily grown as a livestock feed. Presently, sorghum is the third largest cereal grown in the United States, and is a preferred crop in areas of low water availability. It is grown for feed, forage, broomcorn, and a sweet syrup.
Current cultivars and landraces of sorghum are derived from several wild species. Crosses between those landraces. and wild species and cultivated sorghums still occur. In the USA. johnsongrass (S. halepense (L.) Pers.), is a troublesome weed with which cultivated sorghums cross-pollinate (Doggett, 1988).
Some of the major concerns that have been addressed while discussing the biosafety and environmental impacts of genetically engineered crops in general, are potential for gene escape, environmental consequences of gene escape, and safeguards to prevent or minimize gene escape. Some of the biosafety questions that can be specifically asked of sorghum are: (1) will genetically engineered sorghum reduce the number of landraces of sorghum. or otherwise alter the available gene pool of sorghum? This is aquestion related to effects of biotechnology on biodiversity and germplasm; (2) will genetically engineered sorghum alter or otherwise harm wild or weedy species of the genus Sorghum?; (3) will genetically engineered sorghum alter pest resistance to such pests as Striga?; (4) what kind of genes introduced into sorghums lead to weediness or weed problems'?; (5) will genetically engineered sorghum result in a reduction in diversity of cultivated sorghums which will put them at a higher risk for uniform crop failure under seasonal variations in pest and other growing conditions?; and (6) will genetically engineered sorghum result in altered agronomic practices such as purchased seed versus saved seed, shifts toward monoculture, dependence on outside inputs, etc., which will have long term effects on land or agriculture sustainability?
The deliberation on the biosafety of genetically engineered sorghums is extremely important as it serves as a platform for discussions on the assessment of biotechnology applied to sorghums, including its cost-benefits, and is very crucial for technology transfer, trade and agricultural production in the developing countries. The recommendations from this workshop will pave way for the international harmonization of biotechnology regulatory policies.
The presentations that will follow in this special issue will no doubt highlight the biology and cultivation practices of sorghums in different parts of the world. and set a stage for lively discussions on the above listed questions. Most importantly, the discussions will also throw light on the future direction of the applications of plant molecular biology and genetic engineering to the improvement of sorghum.
In 1988/89, USDA/APHIS initiated an active series of scientific, technical, and policy discussions involving scientific, industrial, and professionally active groups and individuals to address critical needs and questions related to the increasing challenges of the rapidly advancing field of agricultural biotechnology. These series of national and international level discussions came to be known as Biotechnology Regulatory Support Activities. So far, USDA/APHIS have sponsored several of such international level workshops and discussions that have positively influenced the development of biotechnology regulatory policies throughout the world. Considering the economic importance of sorghum in the world, APHIS/BBEP strongly believed that an international consultation on various biosafety aspects should be organized to recommend certain good developmental and cultural practices while growing genetically engineered sorghums on a large scale.
Casas, A.M., Kononowicz, A.K., Zehr, U.B.Tomes, D.T., Axtell, J.D., Butler,L.G., Bressan, R.A. and Hasegawa, P.N. 1993. Transgenic sorghum plants via microprojectile bombardment. Proceedings of the National Academy of Sciences USA. 90:11212-11216.
Doggert. H. 1988. Sorghum. Second Edition. Longman Scientific & Technical, New York, NY, USA. 512pp.
Copyright 1995 African Crop Science Society