Microsatellite repeat sequences were investigated as sequenced-tagged site (STS) DNA markers to determine the potential for genetic analysis of the grapevine genome. The PCR-generated markers detect codominant alleles at a single locus or site in the genome. The marker type is very informative detecting high heterozygosity (69%-88%) within individual grapevine cultivars and high genetic variation between cultivars, making it a useful marker type for plant genome mapping and genome typing. For five loci a screening of 26 V. vinifera cultivars found 13, 12, 8, 5, and 4 different length alleles respectively with some alleles more common than others. The genomic DNA sequences surrounding microsatellite sequences were conserved within the genus permitting STS primers to amplify STSs from other Vitis species. These Vitis species were found to have some unique alleles not present in V. vinifera.

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 fruitspecific 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.

Rooted cuttings of grapevines (Vitis vinifera L. cv. Sultana; syn. Thompson Seedless) were grown under glasshouse conditions and supplied with dilute nutrient solution containing either 0 or 90 mM of added NaCl. Growth and photosynthetic response to salt treatment and subsequent recovery were followed over 80 days. Shoot growth and photosynthesis were reduced by salt treatment. At relatively low concentrations of leaf chloride (< c. 150 mM, on a tissue water basis), photosynthetic reduction was largely due to increased stomatal resistance. Internal disturbances were involved at higher leaf Cl- concentrations (> c. 150 mM) and included an apparent reduction in photochemical efficiency and a faster rate of photorespiration. Levels of fraction I protein, and specific activity of ribulose-1,5-bisphosphate carboxylase measured in vitro, were not reduced by salt treatment. Vines showed remarkable adaptation to salinity insofar as leaves maintained positive turgor despite leaf Cl- concentrations exceeding 300 mM, implying osmotic adjustment. Cessation of salt treatment led to an immediate decrease in leaf Cl-, a promotion of shoot growth and a progressive recovery in photosynthesis accompanied by a marked but not necessarily concurrent reduction in both stomatal and internal resistances. Leaves tolerated Cl- levels up to 200 mM (under glasshouse conditions) without sustaining permanent reduction in photosynthetic activity. New shoots formed subsequent to stress relief are not a prerequisite for Cl- retranslocation from mature leaves as decapitation at the time of stress relief did not prevent attenuation of leaf Cl- or recovery in photosynthesis.

With established ampelographic techniques for grapevine identification it is often difficult to achieve a satisfactory, objective result. We have developed a DNA typing system using sequence-tagged microsatellite site markers as a means of differentiating cultivars of grapevine. A semi-automated analysis procedure was linked to an electronic database and found to be an objective and reliable system for cultivar identification using this simple marker type. The accumulated DNA typing data from over eighty cultivars demonstrated that cultivars that are difficult to differentiate phenotypically using ampelographic techniques can be distinguished by DNA typing. Parentage analysis uncovered errors in parent assignment or cultivar identification in specific cases. The electronic database has a conservative format to take into account the occurrence of null alleles and the possibility of missed alleles. Computer-assisted comparisons of cultivars in the database can be performed and various approaches for estimating the match probability that two unrelated cultivars have the same genotype simply due to chance are discussed. We suggest that further development of the database through international co-operation using standardised sequence-tagged site markers offers the possibility of achieving a universal grapevine identification system.

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A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.

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Both random amplified polymorphic DNA and microsatellite repeat sequences were investigated as DNA markers for distinguishing hop cultivars . Microsatellite sequences converted to STS markers proved to be most successful .The relative abundance of microsatellite repeat sequences in the hop genome varied depending on the sequence class . Of the repeat types investigated the dinucleotide repeats (GA)" and (GT)" are the most highly represented in the hop genome . Microsatellite repeat sequences in hops have been shown to be highly polymorphic and are very informative as STS molecular markers . A DNA typing system using sequence-tagged microsatellite site markers has been developed which will not only be useful for hop cultivar identification but also marker assisted breeding and quality control purposes .