RESUMEN
Recently seven National Academies of Science produced a report on transgenic plants and world agriculture. The report provides scientific perspectives to the ongoing public debate about the potential role for transgenic technology in world agriculture. In this article, we develop the themes of the report and emphasize the potential for future genetically modified (GM) crops with a poverty focus, emphasizing the potential of GM resistance to plant parasitic nematodes for subsistence potato farmers in Bolivia. We judge that a range of incremental gains to crop yields from many transgenes are valuable for future world security. We advocate the establishment of a standard that GM crops must achieve before they are both biosafe and appropriate for resource-poor farmers and we believe that the best interests of the poor require biotechnologists to work towards that objective.
Asunto(s)
Plantas Comestibles/genética , Agricultura , Biotecnología , Bolivia , Países en Desarrollo , Ecosistema , Ingeniería Genética/economía , Humanos , Infecciones por Nematodos/prevención & control , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/parasitología , Plantas Modificadas Genéticamente , Pobreza , Seguridad , Solanum tuberosum/genética , Solanum tuberosum/parasitologíaRESUMEN
Rice (Oryza sativa) is sensitive to salinity, which affects one-fifth of irrigated land worldwide. Reducing sodium and chloride uptake into rice while maintaining potassium uptake are characteristics that would aid growth under saline conditions. We describe genetic determinants of the net quantity of ions transported to the shoot, clearly distinguishing between quantitative trait loci (QTL) for the quantity of ions in a shoot and for those that affect the concentration of an ion in the shoot. The latter coincide with QTL for vegetative growth (vigor) and their interpretation is therefore ambiguous. We distinguished those QTL that are independent of vigor and thus directly indicate quantitative variation in the underlying mechanisms of ion uptake. These QTL independently govern sodium uptake, potassium uptake, and sodium:potassium selectivity. The QTL for sodium and potassium uptake are on different linkage groups (chromosomes). This is consistent with the independent inheritance of sodium and potassium uptake in the mapping population and with the mechanistically different uptake pathways for sodium and potassium in rice under saline conditions (apoplastic leakage and membrane transport, respectively). We report the chromosomal location of ion transport and selectivity traits that are compatible with agronomic needs and we indicate markers to assist selection in a breeding program. Based upon knowledge of the underlying mechanisms of ion uptake in rice, we argue that QTL for sodium transport are likely to act through the control of root development, whereas QTL for potassium uptake are likely to act through the structure or regulation of membrane-sited transport components.