Volume 117, September 2015, Pages 306–316
Highlights
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- Gene exchange was limited between the populations of D. nobile.
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- Sixty genotypes across six wild populations were used for the study.
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- DNA barcoding of D. nobile using ISSR and DAMD markers.
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- Association of ISSR and DAMD markers with the antioxidant trait of D. nobile.
Abstract
Dendrobium nobile
is an important medicinal orchid having profound importance in
traditional herbal drug preparations and pharmacopeias worldwide. Due to
various anthropogenic pressures the natural populations of this
important orchid species are presently facing threats of extinction. In
the present study, genetic and chemical diversity existing amongst 6
natural populations of D. nobile were assessed using molecular
markers, and the influence of genetic factors on its phytochemical
activity especially antioxidant potential was determined. Molecular
fingerprinting of the orchid taxa was performed using ISSR and DAMD
markers along with the estimation of total phenolics, flavonoids and
alkaloid contents. Antioxidant activity was also measured using DPPH and
FRAP assays which cumulatively revealed a significant level of
variability across the sampled populations. The representatives from
Sikkim in Northeast India revealed higher phytochemical activity whereas
those from Mizoram showed lesser activity. Analysis of molecular
variance (AMOVA) revealed that variation amongst the populations was
significantly higher than within the populations. The data generated by
UPGMA and Bayesian analytical models were compared in order to estimate
the genetic relationships amongst the D. nobile germplasm
sampled from different geographical areas of Northeast India.
Interestingly, identical grouping patterns were exhibited by both the
approaches. The results of the present study detected a high degree of
existing genetic and phytochemical variation amongst the populations in
relation to bioclimatic and geographic locations of populations. Our
results strongly establish that the cumulative marker approach could be
the best suited for assessing the genetic relationships with high
accuracy amongst distinct D. nobile accessions.
Graphical abstract
Abbreviations
- DAMD, Direct Amplification of Minisatellite DNA;
- ISSR, Inter Simple Sequence Repeats;
- PIC, polymorphic information content;
- AMOVA, analysis of molecular variance;
- Rp, resolving power;
- TPC, total phenolic content;
- TFC, total flavonoid content;
- TAC, total alkaloid content;
- DPPH, 1,1-diphenyl-2-picrylhydrazyl;
- FRAP, Ferric reducing antioxidant power
Keywords
- Dendrobium nobile;
- PIC;
- ISSR;
- DAMD;
- Genetic variation;
- Northeast India;
- Phytochemicals;
- Antioxidants;
- Medicinal orchids;
- Genetic diversity;
- Molecular barcoding;
- Medicinal plant
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