Molecular characterization of some taxa belonging to genera Origanum L. and Thymus L.

In this study some Origanum L. and Thymus L. plant materials naturally grown at different locations within the province of Antalya were collected based on the morphological characteristics and classified. Total genomic DNAs belonging to both genera were isolated and investigated using different DNA techniques to gain knowledge of the species, type, location and genotype level utilizing chloroplast, mitochondrial and nuclear genomes. Plant leaf materials used in the study were collected from genotypes grown in various different locations. From each location at least three genotypes were collected for each species during the flowering of plants. The total number of genotypes used in the study was 115 in total, consisting of 63 Origanum samples and 52 Thymus L. samples. 21 SSR primer pairs in a microsatellite technique and utilizing one primer pair in a SCAR technique were used for genetic studies of Origanum L. while CpSSR, CAPS-SSR ("CAPS Microsatellite"), CAPS and DAMD-PCR techniques were used for Thymus L. genetic studies. UPGMA and PCO analyses were utilized using the SSR and SCAR markers obtained from nuclear and cytoplasmic genomes for characterization of Origanum L. genus O. saccatum, O. solymicum, O.husnucanbaseri, O. minutiflorum, O. majorana, O. onites, O. vulgare subsp. hirtum species. The genetic relationships between among the species and genotypes based on the DNA markers agreed with the morphological based taxonomic ranking. In this study species-specific DNA markers were developed specific to O. saccatum, O. solymicum, O. husnucanbaseri, O. minutiflorum, O. majorana, O. onites, O. vulgare subsp. hirtum which belong to Origanum L. genus. These DNA markers developed in this study are SSR markers which are well qualified to be used in the determination of gene flow between species and natural hybrids. Studies revealed that species in Origanum genus have high level of genetic variations and most of them are genetically heterozygous. Further studies also showed that there were great genetic differences among the species grown in different locations indicating the effects of geographic and ecological factors on genetic variations. Genetic differences among the plant genotypes which were collected at horizontal and vertical locations could be related with the essential oil contents. Thus researchers or plant breeders could obtain genotypes with high essential oil contents using the genetic markers identified in this study. In the other part of this study, Thymus L. which is the genus of the most problematic and complicated member of the Lamiaceae family was studied. In the study T. cilicicus, T. revolotus, T. cherlerioides var. isauricus, T. leucotricus var austroanatolicus, T. zygoides var. lycaonicus, T. sipyleus subsp. sipyleus var. sipyleus, T. sipyleus subsp. sipyleus var. davisianus, T. sipyleus subsp. sipyleus var. rosulans and T. longicaulis naturally grown in the Antalya province were studied. In the result of this study, it was observed that the genus Thymus L. has high level of genetic variations at both in intra and inter species level based on the DAMD-PCR analysis. Analyses of chloroplast and mitochondria loci of Thymus L. revealed there were high level of variations in DNA, however, cluster analyses based on the loci could not support the morphological relations based on the morphological observations. Based on the data obtained from this study it was concluded that genotypes in Thymus L. might have some kind of contaminations in terms of genotypic mixture and therefore further studies are required to reanalyzed the genotypes of Thymus L. with additional samples collected from more locations. The use of new markers and DNA sequencing analyses such as ITS, Mat K and microsatellite could be useful in these types of analyses.