Assessment of genetic variation in timothy (Phleum pratense L.) using RAPD and UP-PCR.

DNA-based fingerprinting technologies including random amplified polymorphic DNA (RAPD) and universally primed PCR (UP-PCR), a novel method for studying genetic variation, were employed as genetic markers for assessing genetic diversity and relationships in timothy (Phleum pratense L.). This study sought to identify the genetic background of the genotypes used in timothy breeding. Thirty eight genotypes from fifteen countries were used as test materials. RAPD and UP-PCR dendrograms based on 132 (from 3 primers) and 44 highly reproducible bands, respectively, were analyzed. The electrophoretic gels showed that the PCR products were informative and polymorphic. Different geographic genotype groups were distinguished according to the combined RADP and UP-PCR results. The results demonstrate that methods based on molecular fingerprinting can be used for timothy identification.

Use of RAPD-PCR fingerprinting to detect genetic diversity of soil Streptomyces isolates.

Random amplified polymorphic DNA (RAPD) was used for identification and assessment of genetic diversity between isolates of Streptomyces from soil. Genomic DNA from 18 Streptomyces isolates and 2 reference strains were amplified using four different 10-mer primers. Different DNA fingerprinting patterns were obtained for all the isolates. Electrophoretic and cluster analysis of the amplification products revealed incidence of polymorphism among the isolates and none of them was identical to the reference strains although there were some common amplification bands. Two highly divergent groups were determined among the isolates. The results indicate that RAPD is an efficient method for discriminating and studying genetic diversity of Streptomyces isolates.

Correlation between polymerase chain reaction analysis of the histidine biosynthesis operon, randomly amplified polymorphic DNA analysis and phenotypic characterization of dairy Lactococcus isolates.

A collection of 32 lactococcal strains isolated from raw milk in the Camembert RDO (registered designation of origin) area were phenotypically and genotypically characterized. As expected for environmental isolates, all strains had a Lactococcus lactis subsp. lactis phenotype. The strains were then genotypically identified by the randomly amplified polymorphic DNA (RAPD) technique, using reference strains of lactococci. Two major clusters were identified containing the two subspecies lactis and cremoris. The subspecies lactis cluster could be divided into five subgroups whereas there was a high coefficient of similarity between all strains in the subspecies cremoris cluster. This RAPD classification was then compared with that of a traditional PCR assay using L. lactis species-specific primers corresponding to part of the histidine biosynthesis operon. The two subspecies were differentiated by the size of the fragment amplified (about 200 bp longer for subspecies cremoris). Unlike preliminary phenotypic assignments, the results of PCR experiments corroborated the genotypic identification of the lactococcal strains by RAPD allowing the technique to be reconsidered on the basis of its taxonomic efficiency.

Diversity of lactic acid bacteria associated with ducks.

The diversity of lactic acid bacteria occurring in the crop and intestinal content of ducks of different ages (5 to 34 days) was evaluated using the RAPD-PCR technique and comparative sequence analysis of 16S rRNA. Cluster analysis derived from isolates grown on Rogosa agar used for the enrichment of lactic acid bacteria, revealed at least twenty six different groups of organisms representing species, subspecies and strains belonging to Streptococcus, Enterococcus, Pediococcus, Weissella and Lactobacillus. Homofermentative and heterofermentative lactobacilli were identified, belonging to the phylogenetically defined Lb. acidophilus, Lb. salivarius and Lb. reuteri groups.