Micropropagation and Quantification of Bioactive Compounds in <i>Mertensia maritima</i> (L.) Gray

• Main Authors: Han Yong Park, Doo Hwan Kim, Ramesh Kumar Saini, Judy Gopal, Young-Soo Keum, Iyyakkannu Sivanesan
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: International Journal of Molecular Sciences
• Subjects: carotenoids; cytokinins; γ-linolenic acid; micropropagation; stearidonic acid; tocopherol
• Online Access: https://www.mdpi.com/1422-0067/20/9/2141

The goal of this study was to establish an efficient protocol for the large-scale propagation of <i>Mertensia maritima</i> (L.) Gray, and evaluate the carotenoid, fatty acid, and tocopherol contents in the leaves of in vitro regenerated shoots. Surface-disinfected node and shoot tip explants were placed on semisolid Murashige and Skoog (MS) medium with 0&#8722;16 &#181;M N⁶-benzyladenine (BA), kinetin, (KN), and thidiazuron (TDZ) alone, or in combination with, 1 or 2 &#181;M &#945;-naphthaleneacetic acid (NAA). Of the three different cytokinins employed, TDZ elicited the best results for axillary shoot proliferation. A maximum frequency of shoot initiation above 84%, with a mean of 8.9 and 4.8 shoots per node and shoot tip, respectively, was achieved on the culture medium supplemented with 4 &#181;M TDZ. A combination of TDZ + NAA significantly increased the percentage of multiple shoot formation and number of shoots per explant. The best shoot induction response occurred on MS medium with 4 &#181;M TDZ and 1 &#181;M NAA. On this medium, the node (93.8%) and shoot tip (95.9%) explants produced an average of 17.7 and 8.6 shoots, respectively. The highest root induction frequency (97.4%) and number of roots per shoot (25.4), as well as the greatest root length (4.2 cm), were obtained on half-strength MS medium supplemented with 4 &#181;M indole-3-butyric acid (IBA). The presence of six carotenoids and &#945;-tocopherol in the leaf tissues of <i>M. maritima</i> was confirmed by HPLC. Gas chromatography-mass spectrometry analysis confirmed the presence of 10 fatty acids, including &#947;-linolenic acid and stearidonic acid in the leaf tissues of <i>M. maritima</i>. All-<i>E</i>-lutein (18.49 &#956;g g^&#8722;1 fresh weight, FW), &#945;-tocopherol (3.82 &#956;g g^&#8722;1 FW) and &#945;-linolenic acid (30.37%) were found to be the significant compounds in <i>M. maritima</i>. For the first time, a successful protocol has been established for the mass propagation of <i>M. maritima</i> with promising prospects for harnessing its bioactive reserves.