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ПУБЛИКАЦИИ: обзоры по биотехнологии

  Advances in coffee biotechnology
  Maria Filomena Carneiro
  Centro de Investigacao das Ferrugens do Cafeeiro,
  Quinta do Marques 2780, Oeiras, Portugal


  In the last 28 years, important advances have been made in in vitro coffee culture techniques, putting the crop in a position to benefit from biotechnology. Some systems of plant regeneration have already been optimised in coffee. This constitutes an important achievement with implications for the micropropagation of superior genotypes obtained by conventional breeding programmes and for the application of genetic transformation procedures. Techniques such as somatic embryogenesis, apical meristem and axillary bud culture, induction and development of adventitious buds, culture of zygotic embryos, anther and pollen culture, cell suspension and protoplast culture, and in vitro selection are presently at an advanced stage of development and are being used to improve coffee via biotechnological methods. Some important advances have also been made at the molecular level. The verification that coffee plants are capable of being infected by Agrobacterium tumefaciens and A. rhizogenes strains represents an important achievement. Direct DNA uptake, gene bombardment using the biolistic method and mediation by Agrobacterium are the most effective methods used in coffee transformation. The transient expression of gus (encoding b-glucuronidase) and stable transformation have been detected in both Coffea arabica and C. canephora.

  Insecticidal transgenic plants: are they irresistible?
  Roland Brousseau 1 , Luke Masson 1 and Dwayne Hegedus 2
  1 Biotechnology Research Institute, National Research Council of Canada,
  6100 Royalmount Ave., Montreal, Quebec, H4P 2R2, Canada
  2 Agriculture Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan, S7N 0X2, Canada


  Transgenic plants producing Bacillus thuringiensis toxins show great promise as insect control agents, provided that effective resistance management strategies are implemented early in their product cycle. To be effective, these strategies require detailed knowledge of the toxins' mode of action and of the insect's genetic repertoire of potential resistance genes, knowledge which is still incomplete even in the best studied systems. Unfortunately, insects show great variability in their genetic responses to selection by Bt toxins. At the present time there is no single proven resistance management strategy that may be recommended as a general approach to avoid resistance to transgenic Bt plants.

  Rice Consumption and Vitamin A Deficiency in Asia

  Rice is one of the world's oldest cereal crop, and together with wheat and corn, it is one of the core staple cereals worldwide today. Nearly 94% of all the world™s rice is grown and consumed on the Asian continent, where it is by far the most important food crop. While rice is a good source of calories, it lacks essential nutritional components. In particular, rice contains neither Vitamin A nor beta-carotene, which humans can convert intoVitamin A.

  The environmental risks of transgenic crops: an agroecological assessment
  Miguel A. Altieri
  Department of Environmental Science, Policy and Management,
  Division of Insect Biology, University of California,
  201 Wellman-3112, Berkeley, CA 94720-3112, USA.
  Fax: (1) 510-642-7428
  Email: agroeco3@nature.berkeley.edu
  URL: www.nature.berkeley.edu


  The potential risks associated with transgenic crops (especially herbicide- and insect-resistant crops) are highlighted by focusing on unexpected results following transgenic releases. These potential impacts are evaluated in the context of agroecological goals aimed at making agriculture more socially just, economically viable and ecologically sound. It is concluded that the environmental risks are serious and underplayed by the biotechnology industry. It is argued that public funding of research on transgenic crops that enhance agrochemical use and that pose environmental risks; should be ended and that ecological sustainability, alternative low-input technologies, the needs of small farmers and human health and nutrition should be pursued with greater vigour than biotechnology.

  Genetic manipulation of lignin profiles: a realistic challenge towards the qualitative improvement of plant biomass
  A.-M. Boudet, Deborah Goffner, Christiane Marque,
  Chantal Teulieres and Jacqueline Grima-Pettenati
  UMR CNRS/UPS 5546, Centre de Biologie et Physiologie vegetale,
  Universite Paul Sabatier, 118 route de Narbonne,
  Bat. 4R1, 31062 Toulouse cedex, France.
  Email: amboudet@cict.fr


  Lignins represent an important proportion of the plant biomass (up to 35% of the dry weight for some woody species). Despite their role in the adaptative strategies of vascular plants, they have a negative impact on the agroindustrial utilization of crops and woody species. They reduce forage digestibility and are difficult to extract from lignocelluloses during the pulping process. The recent characterization of lignification genes and their exploitation for modulation of lignin profiles in transgenic plants was a breakthrough in the area of lignification. A large number of transformed plants exhibiting qualitative and quantitative changes in lignins have already been obtained. For some of these plants, preliminary data have already demonstrated their potential industrial interest. In this review, particular attention is paid to features that are critical in the exploitation of these transgenic approaches: compensation mechanisms, potential unwanted side-effects, stability of transgene expression and so on. In addition, the integration of these new materials in the general strategies of breeders and chemists working for the pulp industry is considered. Transgenic plants provide a source of insight into the processes of lignification and generate new plant products which extend the natural chemical variability observed for lignins. It is clear that genetically engineered trees that developed normally but which produced modified lignins (in lower amounts or that can be more easily processed) would lead to substantial industrial and environmental benefits.


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