RESUMEN
The tomato yellow leaf curl virus (TYLCV) gene that encodes the capsid protein (V1) was placed under transcriptional control of the cauliflower mosaic virus 35S promoter and cloned into an Agrobacterium Ti-derived plasmid and used to transform plants from an interspecific tomato hybrid, Lycopersicon esculentum X L. pennellii (F1), sensitive to the TYLCV disease. When transgenic F1 plants, expressing the V1 gene, were inoculated with TYLCV using whiteflies fed on TYLCV-infected plants, they responded either as untransformed tomato or showed expression of delayed disease symptoms and recovery from the disease with increasingly more resistance upon repeated inoculation. Transformed plants that were as sensitive to inoculation as untransformed controls expressed the V1 gene at the RNA level only. All the transformed plants that recovered from disease expressed the TYLCV capsid protein.
Asunto(s)
Cápside/genética , Virus de Plantas/genética , Plantas Modificadas Genéticamente , Verduras/genética , Secuencia de Bases , ADN/química , Técnicas de Transferencia de Gen , Datos de Secuencia Molecular , Enfermedades de las Plantas , Rhizobium/genética , Transcripción Genética , Verduras/microbiologíaRESUMEN
The whitefly-transmitted tomato yellow-leaf curl gemini-virus (TYLCV) is a major pathogen of tomatoes. The wild tomato species Lycopersicon chilense, which is resistant to the virus, was crossed to the cultivated tomato, L. esculentum. The backcross-1 selfed (BC1S1) generation was inoculated and a symptomless plant was selected. This plant was analyzed using 61 molecular markers, which span the tomato genome, to determine which L. chilense chromosome segments were introgressed. A BC2S1 population was cage-inoculated with viroliferous whiteflies (Bemisia tabaci), the natural insect vector of the virus, and subjected to RFLP analysis. Markers on chromosomes 3 and 6 were significantly associated with the level of tolerance; the association of chromosome-6 markers was further substantiated in two additional BC2S1 populations. A tolerant BC2S1 plant which was homozygous for L. chilense introgressions in chromosomes 3, 6 and 7 was crossed to generate a BC3S1 population which was planted in an infested field. A TYLCV-tolerance gene with partial dominance, TY-1, was mapped to chromosome 6; two modifier genes were mapped to chromosomes 3 and 7. Field and whitefly-mediated cage inoculations of nearly-isogenic lines in BC3S3 supported our conclusion that TY-1 is the major TYLCV-tolerance locus.
RESUMEN
Fifteen cases of severe cranio-cerebral injuries (C.C.I.) with hemianopsia and rehabilitation problems are presented. The correlation between the side of the hemianopsia, dexterity, visual motor organization, intellectual functions and rehabilitation outcome are discussed.