TITLE:
Efficient Plant Regeneration from Explants of Compact Oregano (Origanum compactum Bentham)
AUTHORS:
Rajae Benkaddour, Naouar Ben Ali, Alain Badoc, Ouafaa Hamdoun, Ibtissam Boussaoudi, Latifa Azaroual, Patrick Martin, Ahmed Lamarti
KEYWORDS:
Auxins, Cytokinins, Gibberellic Acid, Macronutrients, Micropropagation, Polyamines, Origanum compactum
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.13 No.10,
October
26,
2022
ABSTRACT: Origanum
compactum Benth., a species endemic to Morocco characterized
by its biological activities, is overexploited because of its commercial value
and threatened with extinction. Accordingly, measures for its conservation are
needed. Micropropagation serves as a
solution for the protection and the domestication of this species. In this
investigation, we established a protocol for vegetative multiplication in vitro of Origanum compactum by the axillary bud technique. Six culture media
(SH, SD, N30K, MS, MSm, B5) were tested to determine the most suitable mineral
medium for growth and development of explants. Four cytokinins: Kinetin,
Zeatin, BAP (6-Benzylaminopurine), 2ip (2-Isopentenyladenine) and three
compounds with cytokinin activity: Adénine, 1,3-Diphenylurea (DPU) and
Thidiazuron (TDZ) at five concentrations (0.44, 1.33, 2.22, 3.11, 4.44 μM) were
tested on budding, growth, hyperhydria and rooting. Then three auxins,
Indole-3-acetic acid (IAA), Naphthalene acetic acid (NAA) and Indole butyric
acid (IBA) at four concentrations (1.14, 2.85, 4.56, 6.27 μM) in presence of
2.22 μM BAP were evaluated. The combination of Gibberellic acid (0.29, 1.5,
2.60, 2.89 μM GA3) and three polyamines (Putrescine, Spermidine,
Spermine) at five concentrations (1.134, 3.402, 5.67, 7.938, 11.34 μM) with
cytokinins and auxins were considered. Our results show that Margara medium is
the most efficient and BAP at 2.22 μM is the best cytokinin for development of
the aerial parts, with a regeneration rate of 88, 90%; rhizogenesis is
successful with the combination of 6.27 μM IAA and 2.22 μM BAP. Moreover, the
integration of 2.89 μM GA3 with 2.22 μM BAP and 6.27 μM IAA promotes
vitroplant growth, bud and shoot multiplication and elongation of the aerial
part. The addition of polyamines with 2.22 μM BAP and 6.27 μM IAA does not
improve the root part, but Spermine at 5.67 μM promotes bud and shoot
multiplication with a high percentage of regeneration, and spermidine at the
same concentration gives long explants. Finally, plantlets with good root
development were successfully acclimatized to natural conditions and served as
a source to establish in vitro culture again.