High frequency regeneration protocol for Dendrobium nobile : A model tissue culture approach for propagation of medicinally important orchid species

An Overview of Orchid Protocorm-Like Bodies: Mass Propagation, Biotechnology, Molecular Aspects, and Breeding

“…These authors also observed that arginine at 25 mg L −1 increased direct somatic embryogenesis, instead of callus derived PLBs [137]. Meta-Topolins, a natural aromatic type of cytokinin, were also reported used in induction and regeneration of PLBs in D. nobile, which combined with 0.5 mg L −1 NAA resulted in best PLBs formation (92%) and shoots/explants (9.2) [139]. These same authors observed that addition of polyamines, such as spermidine and putrescine increased regeneration of shoots from PLBs and secondary PLB formation.…”

“…In Dendrobium candidum and Dendrobium nobile, PLBs have also been used to increase the production of bioactive compounds. In D. nobile, an increase was observed in the production of secondary metabolites such as phenols, flavonoids and alkaloids extracted from PLB-micropropagated plants, when compared to the mother plant [139]. In D. candidum, the increase in methyl-jasmonate elicitor concentrations, although resulting in a proportional reduction in PLBs mass gain, increased the concentrations of alkaloids, polysaccharides, phenols and flavonoids when used between 75 and 100 µM [155].…”

“…Ref. [139] used induction of PLBs from pseudostems from in vitro germinated Dendrobium nobile plants in MS + 1.5 mg L −1 TDZ and 0.25% activated charcoal medium and verified 94% explants producing PLBs and up to 11.6 PLBs/explant. These authors observed a somaclonal variation rate close to 6% in the obtained plants, being the main cause of the somaclonal variations detected by molecular markers Random amplified polymorphic DNA (RAPD) and Start codon targeted (SCoT), attributed by the authors to the use and exposure time to TDZ.…”

“…Also the use of topolins meta-Topolins (mT) and meta-Topolins Riboside (mTR), a natural aromatic cytokinin reported as reducing phytotoxic effects in micropropagation, it use not solved the problem of somaclonal variation obtained in vitro [160] and, although was reported increasing efficiency of PLB induction it use not resulted in absence of somaclonal variation in orchids [139].…”

Morphogenesis, Genetic Stability, and Secondary Metabolite Production in Untransformed and Transformed Cultures

“…Chromosomal rearrangements, single-gene mutations, DNA hypomethylation, genome adaptation to differential microelement environments, and the presence of hot spots have been reported to be probable contributors to clonal variability [491][492][493][494][495]. The clonal variations induced in in vitro cultures can be assessed using flow cytometry, random amplified polymorphic DNA (RAPD), inter-simple sequence repeats (ISSR), simple sequence repeats (SSR), and start codon targeted (SCoT) polymorphism [496][497][498][499]. Several articles have been published on assessment of genetic stability in longterm in vitro cultures such as micropropagated shoots of Pinus thunbergii [27], micropropagated Swertia chirayita plantlets [500], micropropagated plants of three diploid and triploid elite tea clones representing Camellia sinensis and C. assamica [501], micropropagated shoot tips of banana [28,502], micropropagated Gerbera jamesonii plants [503,504], micropropagated almond plantlets [505], micropropagated Cleome gynandra [506], micropropagation of Phalaenopsis bellina [29], and regenerants of Stevia [507].…”