Background: Drought stress is the most harmful one among other abiotic stresses with negative impacts on crop growth and development. Drought-hardening is a feasible and widely used method in tobacco seedlings cultivation. It has gained extensive interests due to its role in improving drought tolerance. This research aimed to investigate the role of drought-hardening and to unravel the multiple mechanisms underlying tobacco drought tolerance and adaptation. Results: This study was designed in which various drought-hardening treatments (CK (no drought-hardening), T1 (drought-hardening for 24 h), T2 (drought-hardening for 48 h), and T3 (drought-hardening for 72 h)) were applied to two tobacco varieties namely HongHuaDaJinYuan (H) and Yun Yan-100 (Y). The findings presented a complete framework of drought-hardening effect at physiological, biochemical, and gene expression levels of the two tobacco varieties under drought stress. The results showed that T2 and T3 significantly reduced the growth of the two varieties under drought stress. Similarly, among the various drought-hardening treatments, T3 improved both the enzymatic (POD, CAT, APX) and non-enzymatic (AsA) defense systems along with the elevated levels of proline and soluble sugar to mitigate the negative effects of oxidative damage and bringing osmoregulation in tobacco plants. Finally, the various drought-hardening treatments (T1, T2, and T3) showed differential regulation of genes expressed in the two varieties, while, particularly T3 drought-hardening treatment-induced drought tolerance via the expression of various stress-responsive genes by triggering the biosynthesis pathways of proline (P5CS1), polyamines (ADC2), ABA-dependent (SnRK2, AREB1), and independent pathways (DREB2B), and antioxidant defense-related genes (CAT, APX1, GR2) in response to drought stress. Conclusions: Drought-hardening made significant contributions to drought tolerance and adaptation in two tobacco variety seedlings by reducing its growth and, on the other hand, by activating various defense mechanisms at biochemical and molecular levels. The findings of the study pointed out that drought-hardening is a fruitful strategy for conferring drought tolerance and adaptations in tobacco. It will be served as a useful method in the future to understand the drought tolerance and adaptation mechanisms of other plant species. Graphical Drought-hardening improved drought tolerance and adaptation of the two tobacco varieties. T1 indicates drought-hardening for 24 h, T2 indicates drought-hardening for 48 h, T3 indicates drought-hardening for 72 h

Gerbera (Gerbera jamesonii Bolus ex Hook. F.; Asteraceae), is one of the most economically important ornamental plants due to its aesthetic value. In the present study, we established a micropropagation method for the large-scale production of quality planting material of gerbera ‘Pink Melody’. Eighty-six percent of the capitulum explants produced adventitious shoots (15.44 ± 0.34 shoots per capitulum) on Murashige and Skoogs (MS) medium containing 2 mg L−1 6-benzylaminopurine (BAP) after six weeks of incubation. The highest shoot multiplication rate (17 shoots per explant) was obtained on MS medium supplemented with BAP and meta-Topolin (each at 2 mg L−1) after eight weeks. The micro-shoots were successfully rooted (91.35%) on half-strength MS medium containing 2 mg L−1 indole-3-butyric acid (IBA) within four weeks. The micropropagated plantlets were acclimatized with a 97.5% survival rate and produced flowers with no visible morphological aberrations.

Soybean’s lengthy protocols for transgenic plant production are a bottleneck in the transgenic breeding of this crop. Explants cultured on a medium for an extended duration exhibit unanticipated modifications. Stress-induced somaclonal variations and in vitro contaminations also cause substantial losses of transgenic plants. This effect could potentially be mitigated by direct shoot regeneration without solid media or in-planta transformation. The current study focused primarily on developing a rapid and effective media-free in-planta transformation technique for three soybean genotypes (Wm82) and our newly developed two hybrids, designated as ZX-16 and ZX-3. The whole procedure for a transgenic plant takes the same time as a stable grown seedling. Multiple axillary shoots were regenerated on stable-grown soybean seedlings without the ectopic expression of developmental regulatory genes. An approximate amount of 200 µL medium with a growth regulator was employed for shoot organogenesis and growth. The maximal shoot regeneration percentages in the Wm82 and ZX-3 genotypes were 87.1% and 84.5%, respectively. The stable transformation ranged from 3% to 8.0%, with an average of 5.5%. This approach seems to be the opposite of the hairy root transformation method, which allowed transgenic shoots to be regenerated on normal roots. Further improvement regarding an increase in the transformation efficiency and of this technique for a broad range of soybean genotypes and other dicot species would be extremely beneficial in achieving increased stable transformation.

The Agrobacterium-mediated technique is widely employed for soybean transformation, but the efficiency of this method is still relatively modest, in which multiple factors are involved. Numerous chemical and physiological cues from host plants are needed for A. tumefaciens attraction and subsequent T-DNA integration into the plant genome. Susceptible genotypes may permit this attachment and integration, and the agronomically superior genotypes with susceptibility to A. tumefaciens would play an important role in increasing transformation efficiency. In this study, we aimed to elevate the Agrobacterium-mediated transformation efficiency of soybean by integrating susceptibility alleles from William82 and flavonoids accumulating alleles from LX genotypes in the same soybean line. The crossing was made between LX () and William82 () soybean by hand pollination. Expectedly, the resulting hybrid soybean progenies inherited susceptibility traits and high flavonoid contents (i.e., genistein, genistin, apigenin, naringenin, quercetin, and cinnamic acid) essential for potential plant–pathogen interaction. Furthermore, the progenies and susceptible William82 soybean were subjected to transformation using A. tumefaciens (GV3101) harboring the GmUbi-3XFlag-35S-GFP and reassembled GmUbi3XFlag-35S-GFP: GUS vectors during separate events. Important transformation-related traits like shoot induction and shoot regeneration ability were also significantly improved in progenies. The progenies designated as ZX-3 exhibited superiority over the William82 parental line in all three traits, i.e., shoot induction, regeneration, and Agrobacterium-mediated transformation. The transient transformation efficiency of the ZX-16 line was remarkably higher when half-cotyledon explants were wounded and transformed with A. tumefaciens harboring GUS assembly vector and then co-cultivated on MS medium supplemented with 2 mg/L spermidine, 0.3 g/L GA3, 0.3 mg/L kinetin, and 1.3 mg/L 6-benzylaminopurine. In addition, the shoot elongation was also higher than that of William82 after two weeks of culture on the shoot induction medium. The newly generated soybeans have the potential to serve as a valuable source for high transgene production and represent a promising avenue for future soybean varietal development.

Osteospermum moniliferum is an unexplored shrub with regard to its pharmacological properties. In this study, the antioxidant potential of O. moniliferum was evaluated using the 2,2 diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP) assays. The DPPH assay indicated that the stem methanolic extract demonstrated the most pronounced scavenging capability (83.16%) at the minimal concentration of 15 mg/mL, with IC50 values recorded at 5.08 mg/mL. The IC50 values obtained from the FRAP assay were suboptimal for the leaf extracts (>1000 µg/mL), whereas the stem extracts exhibited remarkable activity, with values of 2.75 mg/mL for methanol, 3.52 mg/mL for chloroform, and 4.49 mg/mL for hexane extracts. The cytotoxicity was evaluated against three human cell lines, viz. breast adenocarcinoma (MCF-7), embryonic kidney (HEK293) and lung carcinoma (A549), using the (MTT) assay. Moderate activity was observed for the leaf (44.66±0.09 µg/µL) and stem (47.37±0.08 µg/µL) hexane extracts for the HEK293 cell line. In contrast, stem methanol, leaf methanol, leaf chloroform and stem chloroform extracts had low cytotoxic activity against the MCF-7 cell line. All extracts exhibited promising antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These findings could potentially contribute to the advancement of naturally derived compounds used in healthcare.