Transcription Factor AtOFP1 Involved in ABA-Mediated Seed Germination and Root Growth through Modulation of ROS Homeostasis in Arabidopsis.

Ovate family proteins (OFPs) are valued as a family of transcription factors that are unique to plants, and they play a pluripotent regulatory role in plant growth and development, including secondary-cell-wall synthesis, DNA repair, gibberellin synthesis, and other biological processes, via their interaction with TALE family proteins. In this study, CHIP-SEQ was used to detect the potential target genes of AtOFP1 and its signal-regulation pathways. On the other hand, Y2H and BIFC were employed to prove that AtOFP1 can participate in ABA signal transduction by interacting with one of the TALE family protein called AtKNAT3. ABA response genes are not only significantly upregulated in the 35S::HAOFP1 OE line, but they also show hypersensitivity to ABA in terms of seed germination and early seedling root elongation. In addition, the AtOFP1-regulated target genes are mainly mitochondrial membranes that are involved in the oxidative-phosphorylation pathway. Further qRT-PCR results showed that the inefficient splicing of the respiratory complex I subunit genes NAD4 and NAD7 may lead to ROS accumulation in 35S::HA-AtOFP1 OE lines. In conclusion, we speculated that the overexpression of AtOFP1 may cause the ABA hypersensitivity response by increasing the intracellular ROS content generated from damage to the intima systems of mitochondria.

Transcriptomic Analysis and Specific Expression of Transcription Factor Genes in the Root and Sporophyll of Dryopteris fragrans (L.) Schott.

Background: Dryopteris fragrans, which is densely covered with glandular trichomes, is considered to be one of the ferns with the most medicinal potential. The transcriptomes from selected tissues of D. fragrans were collected and analyzed for functional and comparative genomic studies. The aim of this study was to determine the transcriptomic characteristics of wild D. fragrans sporangium in tissues from the SR (root), SL (sporophyll), and TRL (sporophyll with glandular trichomes removed). Results: Cluster analysis identified genes that were highly expressed in an organ-specific manner according to read mapping, feature counting, and normalization. The functional map identified gene clusters that can uniquely describe the function of each tissue. We identified a group of three tissue-specific transcription factors targeting the SL, SR, and TRL. In addition, highly expressed transcription factors (TFs) were found in each tissue-specific gene cluster, where ERF and bHLH transcription factors were the two types showing the most distinct expression patterns between the three different tissues. The specific expression of transcription factor genes varied between the different types of tissues. The numbers of transcription factors specifically expressed in the roots and sporophylls were 60 and 30, respectively, while only seven were found for the sporophylls with glandular trichomes removed. The expression of genes known to be associated with the development of glandular trichomes in flowering plants, including MIXTA, ATML1, and MYB106, were also validated and are discussed. In particular, a unigene encoding MIXTA was identified and exhibited the highest expression level in SL in D. fragrans. Conclusions: This study is the first report of global transcriptomic analysis in different tissues of D. fragrans, and the first to discuss these findings in the context of the development of homologous glandular trichomes. These results set the stage for further research on the development, stress resistance, and secondary metabolism of D. fragrans glandular trichomes.

Ovate family protein1 interaction with BLH3 regulates transition timing from vegetative to reproductive phase in Arabidopsis.

Three-Amino-acid-Loop-Extension(TALE) homeodomain transcription factor BLH3 regulates timing of transition from vegetative to reproductive phase. Previous preliminary results obtained using large-scale yeast two-hybrids indicate that BLH3 protein possibly interact with Ovate Family Proteins(OFPs) transcription co-regulators. Nevertheless, it is uncertain whether OFP1-BLH3 complex is involved in regulation of timing of transition from vegetative to reproductive phase in Arabidopsis. The interaction between BLH3 and OFP1 was re-tested and verified by a yeast two-hybrid system. We found that the BLH3-OFP1 interaction was mainly mediated through the BLH3 homeodomain. Meanwhile, this interaction was further confirmed by bimolecular fluorescence complementation (BiFC) in vivo. Further, by establishing protoplast transient expression, we discovered that BLH3 acts as a transcriptional activator, whereas OFP1 functioned as a repressor. The interactions between OFP1 and BLH3 can reduce BLH3 transcriptional activity. The ofp1 mutant lines and blh3 mutant lines, OFP1 overexpress lines and BLH3 overexpress lines can both influence timing of transition from vegetative to reproductive phase. Furthermore, 35s:OFP1/blh3 plants exhibited flowering and leaf quantity similar to that of the wild-type controls. 35s:BLH3/ofp1 plants flowered earlier and had less leaves than wild-type controls, indicating that OFP1 protein might depend partially on BLH3 in its function to regulate the timing of transition from vegetative to reproductive phase. These results support our assumption that, by interacting with OFP1, BLH3 forms a functional protein complex that controls timing of progression from vegetative to reproductive phase, and OFP1 might negatively regulate BLH3 or the BLH-KNOX complex, an important interaction for sustaining the normal transition from vegetative to reproductive phase.

Functional characterization and transcriptional activity analysis of Dryopteris fragrans farnesyl diphosphate synthase genes.

Farnesyl diphosphate synthase (FPS), a key enzyme of the terpene metabolic pathway, catalyzes the precursor of sesquiterpene compounds farnesyl diphosphate (FPP) synthesis, and plays an important role in regulating plant growth and development. Dryopteris fragrans is a medicinal plant rich terpenoids. In this study, the function of the gene was verified in vitro and in vivo, the promoter of the gene was amplified and its transcriptional activity was analyzed. In the present study, we report the molecular cloning and functional characterization of DfFPS1 and DfFPS2, two FPS genes from D. fragrans. We found that the two genes were evolutionarily conserved. Both DfFPS genes were highly expressed in the gametophyte and mature sporophyte leaves, and their expression levels increased in response to methyl jasmonate (MeJA) and high temperature. Both DfFPS proteins were localized in the cytoplasm and could catalyze FPP synthesis in vitro. We also found that the overexpression of DfFPS genes in tobacco plants promoted secondary metabolite accumulation but exhibited negligible effect on plant growth and development. However, the transgenic plants exhibited tolerance to high temperature and drought. The promoters of the two genes were amplified using fusion primer and nested integrated polymerase chain reaction (FPNI-PCR). The promoter sequences were truncated and their activity was examined using the ß-glucuronidase (GUS) gene reporter system in tobacco leaves, and we found that both genes were expressed in the stomata. The transcriptional activity of the promoters was found to be similar to the expression pattern of the genes, and the transcriptional core regions of the two genes were mainly between -943 bp and -740 bp of proDfFPS1. Therefore, we present a preliminary study on the function and transcriptional activity of the FPS genes of D. fragrans and provide a basis for the regulation of terpene metabolism in D. fragrans. The results also provide a novel basis for the elucidation of terpene metabolic pathways in ferns.

The Hypoglycemic Effect of JinQi Jiangtang Tablets Is Partially Dependent on the Palmatine-Induced Activation of the Fibroblast Growth Factor Receptor 1 Signaling Pathway.

JinQi Jiangtang tablet (JQJTT) is a Chinese patent medicine that has been shown to be beneficial for patients with diabetes both preclinically and clinically; however, the molecular mechanism underlying the effects of JQJTT remains unclear. In this study, surface plasmon resonance fishing was employed to identify JQJTT constituent molecules that can specifically bind to fibroblast growth factor receptor 1 (FGFR1), leading to the retrieval of palmatine (PAL), a key active ingredient of JQJTT. In vivo and in vitro experiments demonstrated that PAL can significantly stimulate FGFR1 phosphorylation and upregulate glucose transporter type 1 (GLUT-1) expression, thereby facilitating glucose uptake in insulin resistance (IR) HepG2 cells as well as alleviating hyperglycemia in diabetic mice. Our results revealed that PAL functions as an FGFR1 activator and that the hypoglycemic effect of JQJTT is partially dependent on the PAL-induced activation of the FGFR1 pathway. In addition, this study contributed to the understanding the pharmacodynamic basis and mechanism of action of JQJTT and provided a novel concept for future research on PAL.

Refined-JinQi-JiangTang tablet ameliorates hypertension through activation of FGF21/FGFR1 axis in fructose-fed rats.

The aim of this study was to investigate the therapeutic effect of JQ-R on metabolic hypertension and its correlation with Fibroblast growth factor 21/Fibroblast growth factor receptors 1(FGF21/FGFR1) pathway. In this study, fructose-induced metabolic hypertension rats were used as hypertension models to detect the regulation effect of JQ-R on hypertension. The effects of JQ-R on blood glucose, blood lipids, serum insulin levels and other metabolic indicators of rats were also measured. The effects of JQ-R on FGF21/FGFR1 signaling pathway in model animals were detected by Real-time quantitative PCR and Western blotting. The results showed that JQ-R significantly reduce the blood pressure of model rats in a dose-dependent manner. Meanwhile, fasting insulin, fasting blood glucose, insulin resistance index, total cholesterol and triglyceride levels were significantly decreased, and glucose and lipid metabolism abnormalities were also significantly improved. JQ-R induces these changes along with FGFR1 phosphorylation, which was also detected in JQ-R treated FGF21 knockout mice. These results suggest that JQ-R can reduce blood pressure and improve glucose and lipid metabolism in fructose-induced hypertension rats. Activation of FGF21/FGFR1 signaling pathway to regulate downstream blood pressure and glucolipid metabolism-related pathways may be one of the important mechanisms of JQ-R in regulating blood pressure.

Identification, Expression, and Interaction Analysis of Ovate Family Proteins in Populus trichocarpa Reveals a Role of PtOFP1 Regulating Drought Stress Response.

Ovate family proteins (OFPs) are a family of plant growth regulators that play diverse roles in many aspects of physiological processes. OFPs have been characterized in various plant species including tomato, Arabidopsis, and rice. However, little is known about OFPs in woody species. Here, a total of 30 PtOFP genes were identified from the genome of Populus trichocarpa and were further grouped into four subfamilies based on their sequence similarities. Gene expression analysis indicated that some members of the PtOFP gene family displayed tissue/organ-specific patterns. Analysis of cis-acting elements in the promoter as well as gene expression by hormone treatment revealed putative involvement of PtOFPs in hormonal response. Furthermore, PtOFP1 (Potri.006G107700) was further experimentally demonstrated to act as a transcriptional repressor. Yeast two-hybrid assay showed physical interactions of PtOFP1 with other proteins, which suggests that they might function in various cellular processes by forming protein complexes. In addition, overexpression of PtOFP1 in Arabidopsis conferred enhanced tolerance to PEG-induced drought stress at seedling stage, as well as a higher survival rate than the wild type at mature stage. These results provide a systematic analysis of the Populus OFP gene family and lay a foundation for functional characterization of this gene family.

Mediation of plant-mycorrhizal interaction by a lectin receptor-like kinase.

The molecular mechanisms underlying mycorrhizal symbioses, the most ubiquitous and impactful mutualistic plant-microbial interaction in nature, are largely unknown. Through genetic mapping, resequencing and molecular validation, we demonstrate that a G-type lectin receptor-like kinase (lecRLK) mediates the symbiotic interaction between Populus and the ectomycorrhizal fungus Laccaria bicolor. This finding uncovers an important molecular step in the establishment of symbiotic plant-fungal associations and provides a molecular target for engineering beneficial mycorrhizal relationships.

Dryocrassin ABBA Induces Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells Through a Caspase-Dependent Mitochondrial Pathway.

BACKGROUND: Biological and pharmacological activities of dryocrassin ABBA, a phloroglucinol derivative extracted from Dryopteris crassirhizoma, have attracted attention. In this study, the apoptotic effect of dryocrassin ABBA on human hepatocellular carcinoma HepG2 cells was investigated. MATERIALS AND METHODS: We tested the effects of dryocrassin ABBA on HepG2 in vitro by MTT, flow cytometry, real-time PCR, and Western blotting. KM male mice were used to detect the effect of dryocrassin ABBA on H22 cells in vivo. RESULTS: Dryocrassin ABBA inhibited the growth of HepG2 cells in a concentration-dependent manner. After treatment with 25, 50, and 75 µg/mL dryocrassin ABBA, the cell viability was 68%, 60% and 49%, respectively. Dryocrassin ABBA was able to induce apoptosis, measured by propidium iodide (PI)/annexin V-FITC double staining. The results of real-time PCR and Western ting showed that dryocrassin ABBA up-regulated p53 and Bax expression and inhibited Bcl-2 expression which led to an activation of caspase-3 and caspase-7 in the cytosol, and then induction of cell apoptosis. In vivo experiments also showed that dryocrassin ABBA treatment significantly suppressed tumor growth, without major side effects. CONCLUSIONS: Overall, these findings provide evidence that dryocrassin ABBA may induce apoptosis in human hepatocellular carcinoma cells through a caspase-mediated mitochondrial pathway.