A Novel and Efficient In Vitro Organogenesis Approach for Ajuga lupulina Maxim

Abstract

This work was aimed at establishing an effective approach for in vitro propagation of Ajuga lupulina Maxim, a medicinal and ornamental plant mainly found in eastern Xizang, in the western Sichuan region of China. We report an optimum response in the proliferation of axillary shoots from nodal segment explants (10.2 shoots/explant) on MS medium containing 3.0 mg L−1 of 6-benzyladenine (BA). When BA and TDZ individually or in combination with NAA were employed for adventitious shoot regeneration, shoots and embryo-like structures (ELSs) were noted in the callus from leaf explants. The maximum response of 26.4 shoots /explant (81.6%) and 12.0 ELSs/explant were ascertained on MS medium with 4.0 mg L−1 TDZ and 0.1 mg L−1 NAA. The leaf despite browning still demonstrated a high regeneration capacity. TDZ (2.0 mg L−1) and BA (2.0 mg L−1) along with NAA (0.01 mg L−1) were found to perform well for shoot regeneration via callus from shoot tip explants. The best for rooting was MS medium (half-strength) containing indole-3-butyric acid (IBA: 1.5 mg L−1) and (NAA: 0.5 mg L−1) with the maximum number of roots (25.8 per shoot) and the highest rooting frequency (81.71%). The survival of the plantlets in the greenhouse was 78.2% indicative of successful acclimatization. This work is the first report of a consistent, definitive, and unique protocol for A. lupulina regeneration, paving the way for the in vitro preservation of such significant genetic resources and also further allied systems based on such callus-based or embryo-based approaches.

Adventitious Shoot Regeneration from Leaf Explants in Sinningia Hybrida ‘Isa’s Murmur’

“…It is reported that hyperhydricity is related to cytokinin concentration and type [23][24][25]. In the present study, Kin causes shoot hyperhydration, this result aligning with our previous discoveries on Ajuga lupulina Maxim [26].…”

“…Although the aseptic seeding leaves brown easily, they still sustained high differentiation capacity. The phenomenon has been reported in species of Ajuga lupulina [26]. We suspect that light intensity or light quality may cause browning, but this is not enough to adversely affect the differentiation ability of leaf explants.…”

Chemical Constituents of Ajuga Lupulina and their Anti‐Ferroptosis Activity

“…It is interesting that compound 16 was firstly isolated from the nature. Five abietane diterpenoids (7)(8)(9)(10)(11) show strong inhibitory ferroptosis in HT22 cells.…”

“…[5] The folk usage of the whole plants was to address hypertension, epilepsy, sore throat, and urinary calculi. [6,7] It is reported that the plants contain abundant bioactive metabolites, including diterpenoids, steroids, iridoids, and flavonoids, which have extensive biological effects, such as antioxidative, insect anti-feed, cytotoxic, and antibacterial activities. [6,8] However, the anti-ferroptosis activity of constituents from A. lupulina has not been reported yet.…”

“…Ajuga Lupulina Maxim is a perennial herb that mostly grows in northwestern China [5] . The folk usage of the whole plants was to address hypertension, epilepsy, sore throat, and urinary calculi [6,7] . It is reported that the plants contain abundant bioactive metabolites, including diterpenoids, steroids, iridoids, and flavonoids, which have extensive biological effects, such as antioxidative, insect anti‐feed, cytotoxic, and antibacterial activities [6,8] .…”