RESUMEN
Tomato (Lycopersicon esculentum) plants were transformed with gene constructs containing a tomato alcohol dehydrogenase (ADH) cDNA (ADH 2) coupled in a sense orientation with either the constitutive cauliflower mosaic virus 35S promoter or the fruit-specific tomato polygalacturonase promoter. Ripening fruit from plants transformed with the constitutively expressed transgene(s) had a range of ADH activities; some plants had no detectable activity, whereas others had significantly higher ADH activity, up to twice that of controls. Transformed plants with fruit-specific expression of the transgene(s) also displayed a range of enhanced ADH activities in the ripening fruit, but no suppression was observed. Modified ADH levels in the ripening fruit influenced the balance between some of the aldehydes and the corresponding alcohols associated with flavor production. Hexanol and Z-3-hexenol levels were increased in fruit with increased ADH activity and reduced in fruit with low ADH activity. Concentrations of the respective aldehydes were generally unaltered. The phenotypes of modified fruit ADH activity and volatile abundance were transmitted to second-generation plants in accordance with the patterns of inheritance of the transgenes. In a preliminary taste trial, fruit with elevated ADH activity and higher levels of alcohols were identified as having a more intense "ripe fruit" flavor.
RESUMEN
The heteroplasmy of chloroplast DNA (cpDNA) observed in Medicago sativa L., which involves the presence (type B) or absence (type A) of an Xba I restriction site, was examined using closed fragments covering the variable XbaI site from type-A and type-B cpDNA. The 6.2-kb PstI fragment of DNA from type-A cpDNA (-XbaI) and from type-B cpDNA (+XbaI) was cloned into pUC19 plasmids. EcoRI fragments bearing the variable XbaI site from the type-A and type-B 6.2-kb PstI fragments were subcloned into pUC19. DNA sequences of both types of the 696-bp EcoRI fragments were determined and computer-assisted analysis of the sequence data carried out. Type-A cpDNA was found to differ from type-B cpDNA by 1 base, a G to T conversion, which results in a non-recognition site for XbaI in the type-A cpDNA. The sequence difference was in a non-coding region. Cloning and sequencing of the fragments verified the individual identity of the type-A and type-B cpDNA.
RESUMEN
Biovar 1 strains ofAgrobacterium tumefaciens have been used to transform a cell suspension culture ofVitis vinifera cv. Cabernet Sauvignon. Cocultivation of cultures withAgrobacterium strains bearing either the cointegrate pGV3850::1103neo, or the binary vector pGA474-68, each gave rise to kanamycin resistant tissue. The stable integration and expression of the neomycin phosphotransferase gene was confirmed by Southern blotting and enzymic assay, respectively.
RESUMEN
A PstI 7.7 kbp fragment from chloroplast (ct) DNA of spinach shows homology to an EcoRI 8.3 kbp fragment of mitochondrial (mt) DNA and in turn, both are homologous to a number of common regions of nuclear (n) DNA. The common area of homology between the chloroplast and mitochondrial fragments is between a KpnI 1.8 segment internal to the PstI sites in the ctDNA and an EcoRI/BamHI 2.9 kbp fragment at one end of the mitochondrial 8.3 kbp fragment. The KpnI 1.8 kbp ctDNA fragment is within a structural gene for the P700 chlorophyll a apoprotein. Further analysis of this KpnI 1.8 kbp fragment confined the homologous region in mtDNA to a ct 0.8 kbp HpaII fragment. These smaller pieces of the organellar genomes share homologies with nuclear DNA as well as displaying unique hybridization sites. The observations reported here demonstrate that there is a common or closely related sequence in all three genetic compartments of the cell.