CbMYB108 integrates the regulation of diterpene biosynthesis and trichome development in Conyza blinii against UV-B.

Plants synthesize abundant terpenes through glandular trichomes (GTs), thereby protecting themselves from environmental stresses and increasing the economic value in some medicinal plants. However, the potential mechanisms for simultaneously regulating terpenes synthesis and GTs development remain unclear. Here, we showed that terpenes in Conyza blinii could be synthesized through capitate GTs. By treating with appropriate intensity of UV-B, the density of capitate GTs and diterpene content can be increased. Through analyzing corresponding transcriptome, we identified a MYB transcription factor CbMYB108 as a positive regulator of both diterpene synthesis and capitate GT density. Transiently overexpressing/silencing CbMYB108 on C. blinii leaves could increase diterpene synthesis and capitate GT density. Further verification showed that CbMYB108 upregulated CbDXS and CbGGPPS expression in diterpene synthesis pathway. Moreover, CbMYB108 could also upregulated the expression of CbTTG1, key WD40 protein confirmed in this study to promote GT development, rather than through interaction between CbMYB108 and CbTTG1 proteins. Thus, results showed that the UV-B-induced CbMYB108 owned dual-function of simultaneously improving diterpene synthesis and GT development. Our research lays a theoretical foundation for cultivating C. blinii with high terpene content, and broadens the understanding of the integrated mechanism on terpene synthesis and GT development in plants.

Evaluation of anti-amnesic effect of Conyza bonariensis in rats.

OBJECTIVE: Conyza bonariensis is an ornamental medicinal weed. This experiment was planned to explore the outcome of petroleum ether extract of C. bonariensis (PECB) leaves on scopolamine-induced amnesia in rats. MATERIALS AND METHODS: For impairing memory, 0.4 mg/kg (i. p.) of scopolamine was given. Fifty to 200 mg/kg of PECB was fed orally to rats and 3 mg/kg (i. p.) of tacrine was given as a standard drug. Anti-amnesic property was evaluated in Barnes maze using ANY-maze software. Following a behavioral study, acetylcholinesterase (AChE), ß-amyloid1-41, antioxidant enzymes, and cytokine levels were measured. Furthermore, reverse transcription-polymerase chain reaction was done for expression of the marker genes such as AChE, Nrf2, NF-κB, PP2A, and HO-1, whereas BDNF, TrkB, caspase-3, and Bax were measured by Western blotting. RESULTS: PECB and tacrine significantly improved memory dysfunction by decreasing escape latency in Barnes maze. At the highest dose, treatment with PECB altered the scopolamine-induced hyperactivation of AChE and ß-amyloid1-41 activity. PECB elevated the levels of superoxide dismutase, glutathione, and catalase and decreased lipid peroxidation and nitric oxide dose dependently. PECB attenuated scopolamine-induced increase of tumor necrosis factor-α and interleukin (IL)-1ß concentrations in the hippocampus with reversed diminished IL-10 level toward normal in the brain. Nrf2, HO-1, PP2A, BDNF, and TrkB were significantly upregulated with downregulation of AChE, NF-κB, Tau, Bax, and caspase-3. Different components such as beta-amyrin and alpha-amyrin were isolated from leaves of the plant. CONCLUSION: The results indicated that PECB might be a potential curative drug for the treatment of cognitive impairment.

Garlic (Allium sativum) based interplanting alters the heavy metals absorption and bacterial diversity in neighboring plants.

Heavy metals are naturally occurring elements that have a high atomic weight and let out in the environment by agriculture, industry, mining and therapeutic expertise and thrilling amassing of these elements pollutes the environment. In this study we have investigated the potential of garlic interplanting in promoting hyper accumulation and absorption of heavy metals to provide a basis for phytoremediation of polluted land. Monoculture and inter-plantation of garlic were conducted to investigate the absorption of cadmium and lead contamination in the land. A group of experiments with single planting (monoculture) of Lolium perenne, Conyza canadensis and Pteris vittata as accumulators were used. The results have shown that garlic has a potential as a hyper accumulate and absorb heavy metals. It was found that the accumulation of Cd and Pb was much higher with inter-planting. Garlic boosts up the absorption of heavy metals in Lolium perenne of Cd 66% and Pb 44% respectively. The Inter-planting of garlic with Pteris vittata promotes the Cd 26% and Pb 15%. While the maximum accumulation of Lead 87% and Cadmium 77% occurred in Conyza canadensis herb plant. The bacterial diversity in the soil was analyzed for each experimental soil and was found that the Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes, and Planctomycetes were commonly abundant in both single planting (monoculture) of ryegrass and interplanting ryegrass with garlic habitats. Variances were observed in the bacterial floral composition of single (monoculture) and intercropping (interplant) soils. Relative abundance of bacterial taxa revealed that the proportion of Proteobacteria, Acidobacteria, and Actinobacteria in the inter-planting group was slightly higher, while Firmicutes and Planctomycetes were low. This study provides the evidence to control the heavy metals contaminated soils with weed species. Growth promotion and heavy metal uptake of neighboring plants proved the specific plant-plant and plant-microbial associations with garlic plants. This inter-planting strategy can be used to improve heavy metal absorption.

Ferrous iron-induced increases in capitate glandular trichome density and upregulation of CbHO-1 contributes to increases in blinin content in Conyza blinii.

MAIN CONCLUSION: Ferrous iron can promote the development of glandular trichomes and increase the content of blinin, which depends on CbHO-1 expression. Conyza blinii (C. blinii) is a unique Chinese herbal medicine that grows in Sichuan Province, China. Because the habitat of C. blinii is an iron ore mining area with abundant iron content, this species can be used as one of the best materials to study the mechanism of plant tolerance to iron. In this study, C. blinii was treated with ferrous-EDTA solutions at different concentrations, and it was found that the tolerance value of C. blinii to iron was 200 µM. Under this concentration, the plant height, root length, biomass, and iron content of C. blinii increased to the maximum values, and the effect was dependent on the upregulated expression of CbHO-1. At the same time, under ferrous iron, the photosynthetic capacity and capitate glandular trichome density of C. blinii also significantly increased, providing precursors and sites for the synthesis of blinin, thus significantly increasing the content of blinin. These processes were also dependent on the high expression of CbHO-1. Correlation analysis showed that there were strong positive correlations between iron content, capitate glandular trichome density, CbHO-1 gene expression, and blinin content. This study explored the effects of ferrous iron on the physiology and biochemistry of C. blinii, greatly improving our understanding of the mechanism of iron tolerance in C. blinii.

Synthesis and characterization of phytochemical fabricated zinc oxide nanoparticles with enhanced antibacterial and catalytic applications.

A "green route" to fabricate nanoparticles has emerged as a revolutionary approach. The reported work presents a green approach to synthesize ZnO nanoparticles using Conyza canadensis plant leaves extract. The synthesis of ZnO was conducted at two different temperatures i.e. 30 °C and 80 °C. ZnO nanoparticles prepared at 80 °C were smaller in size and exhibited spherical morphology. The prepared nanomaterials were examined for the reduction of organic dyes i.e. methylene blue and methyl orange. The fabricated ZnO nanoparticles synthesized at 80 °C were found to be highly active for the reduction of aforementioned dyes with 94.5% reduction of MO and 85.3% reduction of MB in 45 min and 20 min respectively. The rate constant (k) for this reduction of MO was found to be 5.781 × 10-3 s-1 in the absence of a catalyst and 5.843 × 10-2 s-1 in the presence of ZnO NPs catalyst. The rate constant (k) for the reduction of MB was found to be 4.7 × 10-3 s-1 in the absence of a catalyst and 9.936 × 10-3 s-1 in the presence of ZnO NPs catalyst. ZnO nanoparticles synthesized at 80 °C were examined for their antibacterial activity. The biogenic ZnO nanoparticles exhibited strong antibacterial activity against E. coli and S. aureus with a zone of inhibition (16 mm) and (14 mm) respectively. This high antibacterial and catalytic activity of biogenic ZnO nanoparticles can be attributed to its small size, good dispersion, and well-defined morphology.