No abstract

Matricaria chamomilla L. (chamomile, Asteraceae) (GRIN, The Plant List 2013) has a long history of usage in traditional herbal medicine and is still today amongst the most important medicinal plants. Despite this importance, genetic diversity of cultivated and wild germplasm of M. chamomilla was rarely investigated so far. The objective of this study was to estimate the mitochondrial (mt) diversity of various cultivated M. chamomilla genotypes by determining point mutations in the mt genome. 89 SNPs (single nucleotide polymorphisms) were identified in the next generation sequencing data of 33 genotypes from 11 di- and tetraploid chamomile accessions representing a sequence diversity of 0.32 SNPs/kb. Based on the SNP analysis 19 mitochondrial haplotypes (mitotypes) could be specified with genetic distances ranging between 0.011 and 0.851. The examined mt variability within the accessions was higher than expected; only one monomorphic accession (variety ‘Camoflora’) was identified. Diploid accessions exhibited with 1.9 mitotypes per accession a higher variability than tetraploid accessions with a ratio of 1.3. Although some of the mitotypes were distributed over different accessions, identical mitotypes within di- and tetraploid accessions could not be determined. Furthermore, the mitotypes did not correspond to the geographical origin of the accessions. Although not the whole mt genome could be assembled in this study, the substitutions identified represent a valuable tool for further investigations of maternal phylogenetic relationships within M. chamomilla.

Verbenae herba is a widely used drug and consists of the aerial parts of Verbena officinalis (Verbenaceae). Until now, the identification has been performed based on morphological and phytochemical analyses, which are not reliable enough to distinguish Verbena officinalis from other relevant species of the genus Verbena. Hence, impurities and adulterants, negatively influencing the therapeutic effect of the drug, may remain undetected. In an attempt to generate an accurate authentication method we used two different DNA-based approaches: comparison of ITS sequences and molecular markers (RAPD). Both approaches generally enabled discrimination of V. officinalis from the rest of the genus despite the intraspecific variation existing within V. officinalis. The application of the two independent methods, supporting each other, increases the security of identification. For better reproducibility and faster analysis, however, a SCAR marker and primers for HRM were derived from the RAPD results. The SCAR marker could distinguish V. officinalis from all other verbena species except its closest relative V. hastata, while discrimination of V. officinalis even from V. hastata was unproblematic with HRM.

Comfrey Symphytum officinale L. (true comfrey) and S. × uplandicum Nyman (a hybrid between S. asperum Lepech × S. officinale L., Russian comfrey) are used externally for the treatment of pain, inflammation and swelling of muscles and joints in degenerative arthritis, in acute myalgia, sprains, contusions and strains after accidents. Besides plant secondary compounds associated with beneficial activities (e.g. rosmarinic acid and allantoin) comfrey forms also toxic pyrrolizidine alkaloids (PA). To improve further breeding and study the genetic relationships of a comfrey collection, a sample set of 219 S. officinale and 5 hybrid plants of S. × uplandicum were analysed with 34 SNP markers by KASP (Kompetitive Allele Specific PCR), developed from a next generation sequencing approach of three different individuals of S. officinale. In parallel, the plants were analysed for the polyphenol rosmarinic acid, the purine derivative allantoin, and the toxic pyrrolizidine alkaloids. Besides the two beneficial compounds, further 13 polyphenols and 10 purine derivatives were determined. The plants were grouped into six distinct genetic clusters. Rosmarinic acid was not linked to any of the clusters, while one cluster was distinctively different for some compounds, amongst them allantoin and globoidnan A. Also linked to a certain genetic cluster was a low content of PA, which could become a valuable gene pool for minimizing PA content by breeding. A subset of the samples was analysed in a second year again where rosmarinic acid and allantoin showed a medium stability, while globoidnan A was completely unstable.

No abstract

Matricaria chamomilla L. (GRIN; The Plant List 2013) is an important medicinal plant and one of the most frequently consumed tea plants. In order to assess mitochondrial genome variation of different cultivated chamomile accessions, 36 mitochondrial SNP markers were used in a HRM (high resolution melting) approach. In thirteen accessions of chamomile (n = 155), twenty mitochondrial haplotypes (genetic distances 0.028–0.693) were identified. Three of the accessions (‘Camoflora’, ‘Mat19’ and ‘Manzana’) were monomorphic. The highest genotypic variability was found for the Croatian accession ‘PG029’ with nine mitochondrial haplotypes (mitotypes) and the Argentinian ‘Argenmilla’ with seven mitotypes. However, most of the mitotypes detected in these accessions were infrequent in our sample set, thus disclosing an unusual high amount of substitutions within the mitochondrial genome of these accessions. The mitotypes with the highest frequency in the examined dataset were MT1 (n = 27), MT9 (n = 23) and MT17 (n = 20). All of the frequent mitochondrial lines are distributed not only over several accessions but also over several geographical origins. The origins often build a triplet with on average two to three concurrent lines. The most distantly related accessions were ‘Mat19’ and ‘Camoflora’ (0.539), while ‘PNOS’ and ‘Margaritar’ (0.007) showed the lowest genetic distance.

Premise of the study:For the economically important species Calendula officinalis, a fast identification assay based on high-resolution melting curve analysis was designed. This assay was developed to distinguish C. officinalis from other species of the genus and other Asteraceae genera, and to detect C. officinalis as an adulterant of saffron samples.Methods and Results:For this study, five markers (ITS, rbcL, 5′ trnK-matK, psbA-trnH, trnL-trnF) of 10 Calendula species were sequenced and analyzed for species-specific mutations. With the application of two developed primer pairs located in the trnK 5′ intron and trnL-trnF, C. officinalis could be distinguished from other species of the genus and all outgroup samples tested. Adulterations of Calendula DNA in saffron could be detected down to 0.01%.Conclusions:With the developed assay, C. officinalis can be reliably identified and admixtures of this species as adulterant of saffron can be revealed at low levels.

No abstract