Mutagenesis as viewed from another perspective

Mutation has generally been considered a random process, not directed. Thus, a mechanism allowing for adaptively responsive mutagenesis has conceptually been precluded. However, an adaptively directed mutagenesis in response to environmental stress can be based upon genetic mutator systems. Such systems, known for years, have been seen as exceptional and not considered in terms of an adaptively responsive mutagenesis. Environmental stress which invokes this type of mutagenesis can thus be regarded as mutagenic itself, and our concept of what is mutagenic must therefore be broadened. Relevant matters are also discussed.     

生命伦理学视野下的转基因作物产业化问题研究

转基因作物的产业化作为当前生命伦理学的重要问题之一日益受到我国学术界、政府和广大公众的关注。转基因作物产业化不仅关涉到我国13亿人的吃饭问题,也与我国公众的身心健康、基本权利密切相关。转基因作物产业化的生命伦理意蕴主要体现在：转基因作物产业化的基础是确保公众健康与生命安全,关键是尊重公众权利,核心是促进社会公正。     

Transgenic crops expressing Bacillus thuringiensis toxins and biological control

The area devoted to growing transgenic plants expressing insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) is increasing worldwide. A major concern with the adoption of Bt crops is their potential impact on nontarget organisms including biological control organisms. Regulatory frameworks should advocate a step-wise (tiered) approach to assess possible nontarget effects of Bt crops. Laboratory and glasshouse studies have revealed effects on natural enemies only when Bt-susceptible, sublethally damaged herbivores were used as prey or host, with no indication of direct toxic effects. Field studies have confirmed that the abundance and activity of parasitoids and predators are similar in Bt and non-Bt crops. In contrast, applications of conventional insecticides have usually resulted in negative impacts on biological control organisms. Because Bt-transgenic varieties can lead to substantial reductions in insecticide use in some crops, they can contribute to integrated pest management systems with a strong biological control component.     

Transgenic oilseed crops as an alternative to fish oils

Growing evidence suggests that omega-3 long chain polyunsaturated fatty acids (VLC-PUFAs), especially eicosapentaenoic acid (EPA; 20:5Δ5,8,11,14,17) and docosahexaenoic acid (DHA; 22:6Δ4,7,10,13,16,19) play critical roles in human health and development. VLC-PUFAs are mainly found in fish, some fungi, marine bacteria and microalgae. Currently, the predominant dietary sources of VLC-PUFAs are marine fish and seafood. However, the increasing demand for fish and fish oils is putting enormous pressure on marine ecosystems leading to a depletion of fish stocks while commercial cultivation of marine microorganisms and aquaculture are not sustainable and cannot compensate for the shortage in fish supply. Therefore, there is an obvious requirement for an alternative and sustainable source for VLC-PUFAs. Over the last decade, many genes encoding the primary VLC-PUFAs biosynthetic activities became available providing a toolkit for the “reverse-engineering” of transgenic plants to produce fish oils. In this review, we will describe the recent advances in this field and the insights they give us into the complexities of metabolic engineering of oil-seed crops producing VLC-PUFAs.     

Breeding for micronutrients in staple food crops from a human nutrition perspective

Over three billion people are currently micronutrient (i.e. micronutrient elements and vitamins) malnourished, resulting in egregious societal costs including learning disabilities among children, increased morbidity and mortality rates, lower worker productivity, and high healthcare costs, all factors diminishing human potential, felicity, and national economic development. Nutritional deficiencies (e.g. iron, zinc, vitamin A) account for almost two-thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Importantly, these crops can be enriched (i.e. 'biofortified') with micronutrients using plant breeding and/or transgenic strategies, because micronutrient enrichment traits exist within their genomes that can to used for substantially increasing micronutrient levels in these foods without negatively impacting crop productivity. Furthermore, 'proof of concept' studies have been published using transgenic approaches to biofortify staple crops (e.g. high beta-carotene 'golden rice' grain, high ferritin-Fe rice grain, etc). In addition, micronutrient element enrichment of seeds can increase crop yields when sowed to micronutrient-poor soils, assuring their adoption by farmers. Bioavailability issues must be addressed when employing plant breeding and/or transgenic approaches to reduce micronutrient malnutrition. Enhancing substances (e.g. ascorbic acid, S-containing amino acids, etc) that promote micronutrient bioavailability or decreasing antinutrient substances (e.g. phytate, polyphenolics, etc) that inhibit micronutrient bioavailability, are both options that could be pursued, but the latter approach should be used with caution. The world's agricultural community should adopt plant breeding and other genetic technologies to improve human health, and the world's nutrition and health communities should support these efforts. Sustainable solutions to this enormous global problem of 'hidden hunger' will not come without employing agricultural approaches.     

转基因作物将为我国农业发展注入新动力

随着基因组学研究和生物技术的不断突破,应用生物技术改良农作物品种正成为引发新的农业技术革命的关键。由于转基因品种在生产上表现出的巨大效益,其研发和产业化在全球迅猛发展,并逐渐成为世界各国抢占的生物技术制高点。本文从转基因技术的内涵、国际转基因作物的研发态势、我国转基因作物的研发和产业化现状等方面进行阐述,探讨了大力发展转基因作物对于解决我国目前农业生产上面临的挑战、保障我国粮食安全和农业可持续发展的重要意义。     

Nutritional and phytochemical value of Brassica crops from the agri‐food perspective

Brassica foods are among the top 10 economic crops in the world (i.e. broccoli, kale, cauliflower and Chinese cabbage). These vegetables have been identified as important components of a healthy diet because of their high levels of nutrients and health‐promoting phytochemicals (i.e. phenolics, glucosinolates, vitamins and minerals). Epidemiological studies have shown that increased consumption of Brassica foods is strongly associated with a reduced risk of degenerative diseases, cancer, cardiovascular disease and immune dysfunction. Nevertheless, the nutritional content and profile in Brassica vegetables have been reported to vary considerably during the growth period due to agronomical factors including light, temperature, water availability and soil fertility among others. Moreover, the conditions of postharvest processing and cooking are also important factors on food quality. A better understanding of specific preharvest and postharvest conditions is essential to improve cultivars with value‐added nutritional quality. Thus, in this article are going to be addressed the effects of the most common crop management strategies and processes on the variation of nutritive compounds present within Brassica from the agri‐food perspective.     

Transgenic crops: the present state and new ways of genetic modification

Transgenic crops were first commercialised almost 20 years ago, which makes it a good opportunity to reflect on this technology. In this review, we compare its status with the predictions included in Vasil’s forecast published in 2002. Our analysis shows that science has provided a wide range of possibilities to modify different traits in plants, yet the economy benefits from that range to very different extents. We also point out the most important constituents of the technology development involving methodology improvement and novel traits expressed in varieties introduced into agriculture. Using native genes (or their elements) in transgenes, accumulating previously produced transgenes to cascade resistance and using herbicide resistance as a selectable marker have been considered typical of novel genetically modified (GM) plant varieties. A vast portion of the novelties in stacked varieties is doubtful in terms of EU regulations. Attention has also been directed to completely novel methodology solutions that hold out the prospect of a more comprehensive use of genetic modification in agriculture as a whole, and, particularly, make its use possible in the EU and even in sustainable agriculture.     

Transgenic crops,biotechnology and ownership rights: what scientists need to know

Ownership of intellectual and tangible property (IP/TP) rights in agricultural biotechnology (ag-biotech) and transgenic plants has become critically important. For scientists in all institutions, whether industrialized or developing country, public or private sector, an understanding of IP/TP rights is fundamental in both research and development. Transgenic plants and ag-biotech products embody numerous components and processes, each of which may have IP/TP rights attached. To identify these rights, a transgenic plant or ag-biotech product must be dissected into its essential components and processes, with each 'piece' analysed under the IP/TP 'microscope'. This product deconstruction is an integral step in product clearance (PC) analysis leading to freedom to operate (FTO). To facilitate a PC analysis, the following points are important: (1) knowing what one has and where it's from, (2) organizing material transfer agreements and licences, (3) researching scientific and patent databases and relevant literature, (4) instituting a laboratory notebook policy, (5) keeping track of ownership of germplasm and plant genetic resources, and (6) promoting ongoing IP/TP management, awareness and training. However, a FTO opinion does not solve the IP/TP issues of releasing a transgenic plant or ag-biotech product; rather, it is a management tool for assessing the risks of litigation. When transferring transgenic plants or ag-biotech to developing nations, scientists from industrialized countries have the heightened responsibility of verifying that IP/TP issues are fully addressed and documented. Successful technology transfer goes beyond research, development and licensing; it is an holistic package leading to long-term partnerships in international development. Managing IP/TP requires capacity-building in scientists and technology transfer offices, in both industrialized and developing countries.     

Transgenic crops: trends and dynamics in the world and in Latin America

Transgenic Research - Transgenic crops have been the recipient of strong support as well as vigorously opposed opinions since their appearance. In any case, their growth throughout the world has...     

Ethanol from sugar crops

Soluble sugars, like sucrose, glucose and fructose, are transformed by yeast into ethanol and carbon dioxide. These sugars are stored in photosynthetically efficient plants like sugar cane. Recent developments in the transformation of sucrose present in sugar cane or sweet sorghum into ethanol, include the use of the Tilby machine, a high-temperature extraction process and the Ex-Ferm process. This review covers kinetic aspects of ethanol production, yeast immobilization techniques, yeast properties and fermentation byproducts.     

Gene dispersal from transgenic crops

The risk of release of genetically modified oilseed rape (Brassica napus) was investigated in relation to interspecific gene flow with hoary mustard (Hirschfeldia incana). Microscopic studies showed polymorphism within the population of hoary mustard for pollen germination on oilseed rape flowers. The transgenic herbicide-resistant and a commercial cultivar of oilseed rape were not different for pollen behaviour and ovule fertilization. Pollen tube growth was slow and erratic in interspecific crosses. Fertilization efficiency of oilseed rape and hoary mustard pollen in interspecific crosses was 15% and 1.3%, respectively, of that in intraspecific crosses. This unequal efficiency in reciprocal crosses was confirmed by hybrid seed set in pods. There was no post-zygotic barrier to the development of hybrid embryos in hoary mustard pods. Up to 26 spontaneous hybrids per male sterile oilseed rape plant, and one per hoary mustard plant, were obtained in field experiments. Hybrids were identified by isozyme electrophoresis, morphology and cytology. All hybrids were triploid with 26 chromosomes, and had low fertility. They produced 0.5 seeds per plant after spontaneous backcrossing with hoary mustard. Some of these descendants were produced from unreduced gametes. Our results suggest that gene flow is likely to occur, but its actual frequency under crop growing conditions remains to be estimated.