In vitro propagation from young and mature explants of thyme (Thymus vulgaris and T. longicaulis) resulting in genetically stable shoots

Abstract

An efficient in vitro propagation protocol, applicable both to young and mature explants of two Thymus spp., results in genetically stable plantlets. In vitro-grown shoot tips of Thymus vulgaris L. were exposed to cytokinins (6-benzyladenine, kinetin, and thidiazuron) alone or in combination with auxins, gibberellic acid (GA 3 ) and/or silver nitrate in order to optimize in vitro shoot proliferation. Optimum shoot proliferation (97% regeneration rate, with 8.6 shoots produced per explant) was obtained when semi-solid Murashige and Skoog (MS) medium was supplemented with 1 mg L −1 kinetin and 0.3 mg L −1 GA 3 . Rooting of the shoots was easily obtained on semi-solid MS medium that was either hormone-free or supplemented with auxins. However, the best root apparatus (92.5% rooting rate, with 19 adventitious roots per shoot) developed on MS medium supplemented with 0.05 mg L −1 2,4-dichlorophenoxyacetic acid. Genetic stability was confirmed in the in vitro-germinated mother plant as well as the shoots that underwent two, four, six, eight, or ten cycles of in vitro subculturing by random amplified polymorphic DNA (RAPD) analysis. When applied to the micropropagation of mature shoot tips of T. longicaulis C. Presl subsp. longicaulis var. subisophyllus (Borbás) Jalas, the optimized in vitro propagation protocol resulted in a 97.5% shoot regeneration rate, with five shoots formed per explant, and 100% rooting. Rooted plantlets of both species were transferred to 250-mL plastic pots and successfully acclimatized by gradually reducing the relative humidity.

Genetic Relationship among Wild Medicinal Genotypes of <i>Ziziphora canescens</i> Benth. and <i>Ziziphora tenuior</i> L. and Detection of Genetic Variations Resulted From Tissue Culture, Salinity and pH Media

“…This result are in agreement with Peyvandi et al (2013) who reported all of the mentioned fragments were monomorphic, confirming the genetic stability of the micropropagated plants of Olea europaea. Also agree with Ozudogru et al (2011) who reported all of bands were monomorphic through 10 subculture of Thymus vulgaris and T. longicaulis. In opposite of, ISSR markers showed high polymorphic bands especially in subcultures 7, 8 and 9.…”

“…RAPD markers have been used successfully to assess genetic stability among somatic embryos in spruce species (Isabel et al, 1993;. Panda et al (2007) evaluated the genetic stability of micropropagated clones of Curcuma longa L. over 26 months in culture by random amplified polymorphic DNA (RAPD) analysis, Also Genetic stability of thyme was confirmed in the in vitro-germinated mother plant as well as the shoots that underwent two, four, six, eight and ten cycles of in vitro subculturing by RAPD analysis (Ozudogru et al, 2011). The ISSR markers have also been used successfully to assess genetic stability among micropropagated plants (Joshi and Dhawan, 2007).…”

Establishment of an in vitro propagation protocol for Thymus lotocephalus, a rare aromatic species of the Algarve (Portugal)

“…The essential oils produced by Thymus spp. are important for the cosmetic industry, and due to their antiseptic, antispasmodic and antimicrobial properties, they are also used for medicinal purposes (Cosentino et al 1999;Figueiredo et al 2001;Stahl-Biskup and Saéz 2002;Ozudogru et al 2011). The chemical composition and the antimicrobial activity of T. lotocephalus essential oils have already been reported (Salgueiro et al 2000;Figueiredo et al 2001;Faleiro et al 2003).…”

In vitro callus induction and micropropagation of Thymus persicus (Lamiaceae), an endangered medicinal plant

“…Certain types of callus cultures give rise to clones that have inheritable characteristics different from those of parent plants due to the occurrence of somaclonal variability (George 1993), which can lead to the development of commercially important improved varieties (Lee and Chen 2014). IVP protocols have already been established for Thymus species, such as T. vulgaris and T. longicaulis (Ozudogru et al 2011), and T. lotocephalus (Coelho et al 2012). Recently, micropropagation of T. persicus via direct organogenesis has been reported from our laboratory (Bakhtiar et al 2014).…”