IbMYC2 Contributes to Salt and Drought Stress Tolerance via Modulating Anthocyanin Accumulation and ROS-Scavenging System in Sweet Potato.

Basic helix-loop-helix (bHLH) transcription factors extensively affect various physiological processes in plant metabolism, growth, and abiotic stress. However, the regulation mechanism of bHLH transcription factors in balancing anthocyanin biosynthesis and abiotic stress in sweet potato (Ipomoea batata (L.) Lam.) remains unclear. Previously, transcriptome analysis revealed the genes that were differentially expressed among the purple-fleshed sweet potato cultivar 'Jingshu 6' and its anthocyanin-rich mutant 'JS6-5'. Here, we selected one of these potential genes, IbMYC2, which belongs to the bHLH transcription factor family, for subsequent analyses. The expression of IbMYC2 in the JS6-5 storage roots is almost four-fold higher than Jingshu 6 and significantly induced by hydrogen peroxide (H2O2), methyl jasmonate (MeJA), NaCl, and polyethylene glycol (PEG)6000. Overexpression of IbMYC2 significantly enhances anthocyanin production and exhibits a certain antioxidant capacity, thereby improving salt and drought tolerance. In contrast, reducing IbMYC2 expression increases its susceptibility. Our data showed that IbMYC2 could elevate the expression of anthocyanin synthesis pathway genes by binding to IbCHI and IbDFR promoters. Additionally, overexpressing IbMYC2 activates genes encoding reactive oxygen species (ROS)-scavenging and proline synthesis enzymes under salt and drought conditions. Taken together, these results demonstrate that the IbMYC2 gene exercises a significant impact on crop quality and stress resistance.

Sweet potato NAC transcription factor NAC43 negatively regulates plant growth by causing leaf curling and reducing photosynthetic efficiency.

Leaves comprise one of the most important organs for plant growth and development. Although there have been some reports on leaf development and the establishment of leaf polarity, their regulatory mechanisms are not very clear. In this study, we isolated a NAC (NAM, ATAF, and CUC) transcription factor (TF), i.e., IbNAC43, from Ipomoea trifida, which is a wild ancestor of sweet potato. This TF was highly expressed in the leaves and encoded a nuclear localization protein. The overexpression of IbNAC43 caused leaf curling and inhibited the growth and development of transgenic sweet potato plants. The chlorophyll content and photosynthetic rate in transgenic sweet potato plants were significantly lower than those in wild-type (WT) plants. Scanning electron microscopy (SEM) and paraffin sections showed that the ratio of cells in the upper and lower epidermis of the transgenic plant leaves was unbalanced; moreover, the abaxial epidermal cells were irregular and uneven in transgenic plants. In addition, the xylem of transgenic plants was more developed than that of WT plants, while their lignin and cellulose contents were significantly higher than those of WT. Quantitative real-time PCR (qRT-PCR) analysis showed that the overexpression of IbNAC43 upregulated the genes involved in leaf polarity development and lignin biosynthesis in transgenic plants. Moreover, it was found that IbNAC43 could directly activate the expression of the leaf adaxial polarity-related genes IbREV and IbAS1 by binding to their promoters. These results indicate that IbNAC43 might play a critical role in plant growth by affecting the establishment of leaf adaxial polarity. This study provides new insights regarding leaf development.

Genome-Wide Characterization of the PIFs Family in Sweet Potato and Functional Identification of IbPIF3.1 under Drought and Fusarium Wilt Stresses.

Phytochrome-interacting factors (PIFs) are essential for plant growth, development, and defense responses. However, research on the PIFs in sweet potato has been insufficient to date. In this study, we identified PIF genes in the cultivated hexaploid sweet potato (Ipomoea batatas) and its two wild relatives, Ipomoea triloba, and Ipomoea trifida. Phylogenetic analysis revealed that IbPIFs could be divided into four groups, showing the closest relationship with tomato and potato. Subsequently, the PIFs protein properties, chromosome location, gene structure, and protein interaction network were systematically analyzed. RNA-Seq and qRT-PCR analyses showed that IbPIFs were mainly expressed in stem, as well as had different gene expression patterns in response to various stresses. Among them, the expression of IbPIF3.1 was strongly induced by salt, drought, H2O2, cold, heat, Fusarium oxysporum f. sp. batatas (Fob), and stem nematodes, indicating that IbPIF3.1 might play an important role in response to abiotic and biotic stresses in sweet potato. Further research revealed that overexpression of IbPIF3.1 significantly enhanced drought and Fusarium wilt tolerance in transgenic tobacco plants. This study provides new insights for understanding PIF-mediated stress responses and lays a foundation for future investigation of sweet potato PIFs.

A Novel WRKY Transcription Factor from Ipomoea trifida, ItfWRKY70, Confers Drought Tolerance in Sweet Potato.

WRKY transcription factors are one of the important families in plants, and have important roles in plant growth, abiotic stress responses, and defense regulation. In this study, we isolated a WRKY gene, ItfWRKY70, from the wild relative of sweet potato Ipomoea trifida (H.B.K.) G. Don. This gene was highly expressed in leaf tissue and strongly induced by 20% PEG6000 and 100 µM abscisic acid (ABA). Subcellar localization analyses indicated that ItfWRKY70 was localized in the nucleus. Overexpression of ItfWRKY70 significantly increased drought tolerance in transgenic sweet potato plants. The content of ABA and proline, and the activity of SOD and POD were significantly increased, whereas the content of malondialdehyde (MDA) and H2O2 were decreased in transgenic plants under drought stress. Overexpression of ItfWRKY70 up-regulated the genes involved in ABA biosynthesis, stress-response, ROS-scavenging system, and stomatal aperture in transgenic plants under drought stress. Taken together, these results demonstrated that ItfWRKY70 plays a positive role in drought tolerance by accumulating the content of ABA, regulating stomatal aperture and activating the ROS scavenging system in sweet potato.

A novel sweetpotato RING-H2 type E3 ubiquitin ligase gene IbATL38 enhances salt tolerance in transgenic Arabidopsis.

Arabidopsis Toxicos en Levadura (ATL) proteins compose a subfamily of E3 ubiquitin ligases and play major roles in regulating plant growth, cold, drought, oxidative stresses response and pathogen defense in plants. However, the role in enhancing salt tolerance has not been reported to date. Here, we cloned a novel RING-H2 type E3 ubiquitin ligase gene, named IbATL38, from sweetpotato cultivar Lushu 3. This gene was highly expressed in the leaves of sweetpotato and strongly induced by NaCl and abscisic acid (ABA). This IbATL38 was localized to nucleus and plasm membrane and possessed E3 ubiquitin ligase activity. Overexpression of IbATL38 in Arabidopsis significantly enhanced salt tolerance, along with inducible expression of a series of stress-responsive genes and prominently decrease of H2O2 content. These results suggest that IbATL38 as a novel E3 ubiquitin ligase may play an important role in salt stress response.

The influence of sample size and gender composition on the meta-analysis conclusion of platelet-rich plasma treatment for osteoarthritis.

OBJECTIVE: The magnitude of the therapeutic effects of intra-articular injection of platelet-rich plasma (PRP) on osteoarthritis (OA) is still under debate. The goal of this study that was a systematic review of randomised controlled trials â€‹of PRP injections for the treatment of OA was to elucidate the therapeutic efficacy of PRP. METHODS: Electronic databases of PubMed, CENTRAL, EMBASE, EBSCO, ClinicalTrials.gov, and International Clinical Trials Registry Platform â€‹were searched from inception to June 2018 for RCTs that compared PRP injections to controls in patients with OA. A random-effects approach was used to compile data and subgroups according to trial size (large trials versus small trials), patient profile (age and gender), and PRP preparation method was performed. RESULTS: Thirty trials met the inclusion criteria and were analysed. All results had unexplained statistical heterogeneity. Patients treated with PRP compared with control showed statistically relevant pain relief and function improvement at short term (standardised mean difference [SMD] â€‹= â€‹-0.62, 95% confidence interval [CI]: -0.98 to -0.27, P â€‹= â€‹0.0006, SMD â€‹= â€‹-0.74, 95% CI: -1.11 to 0.36, P â€‹= â€‹0.0001, respectively), medium term (SMD â€‹= â€‹-0.53, 95% CI: -0.83 to -0.23, P â€‹= â€‹0.0006, SMD â€‹= â€‹-0.50, 95% CI: -0.75 to -0.25, P â€‹= â€‹0.0006), and long term (SMD â€‹= â€‹-0.69, 95% CI: -1.08 to -0.30, P â€‹= â€‹0.0006, SMD â€‹= â€‹-0.68, 95% CI: -0.1.09 to -0.27, P â€‹= â€‹0.001, respectively). A subgroup analysis of the data from large trials and from trials composed of less than 50% female patients revealed that therapeutic effects of the treatment are insignificant. CONCLUSIONS: According to the currently available data, PRP injections are beneficial for pain relief and function improvement in patients with OA. This meta-analysis, however, demonstrated that the efficacy of PRP is related to sample size and gender composition. Thus, more randomised controlled trials of high quality and larger patient size, also including gender aspects, are required to understand this phenomenon. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The translation potential of this meta-analysis is that provided another perspective to analyse the treatment effect of PRP for OA. In future research, phenotypes subpopulation and gender difference of OA patient should be considered for PRP treatment.

Synthesis of copolymers using dendronized polyethylene glycol and assay of their blood compatibility and antibacterial adhesion activity.

Thrombus formation and microbial invasion are two major complications that impede the widespread application of blood-contacting devices. The development of new materials that have blood compatibility and antibacterial adhesion activity has gained increased attention. In this study, a new class of polymers composed of hydrophilic dendronized polyethylene glycol (PEG) methacrylate and hydrophobic octyne monomethyl ether-glycidyl methacrylate was synthesized via click chemistry and free radical polymerization. Different polymers were synthesized by changing the ratio of the two monomers. The structures of the synthesized polymers were characterized by (1)H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Their physical properties such as molecular weight, polydispersity, and glass transition temperature were determined using gel permeation chromatography and differential scanning calorimetry. The synthesized polymers were coated on glass slides to prepare a series of polymeric surfaces. Contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy analysis showed that the polymeric surfaces had long-lasting stability. The introduction of the monomer dendronized PEG methacrylate to the polymers greatly improved the hydrophilicity of the polymeric surfaces. The blood compatibility of the synthesized polymers was evaluated by protein (bovine serum albumin and fibrinogen) adsorption and platelet adhesion assays. Their antibacterial adhesion ability was investigated using the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus. The results demonstrated that the amount of adsorbed protein, platelets, and bacteria on the polymeric surfaces decreased with increased content of the hydrophilic monomer dendronized PEG methacrylate in the polymers. However, no obvious difference was observed when such content exceeded 50 mol%. The results suggested that the new kind of polymer could be developed as a promising blood-contact coating material that may have extensive medical applications.

Surface modification of PDMS by surface-initiated atom transfer radical polymerization of water-soluble dendronized PEG methacrylate.

The current paper reports the synthesis of a highly hydrophilic, antifouling dendronized poly(3,4,5-tris(2-(2-(2-hydroxylethoxy)ethoxy)ethoxy)benzyl methacrylate) (PolyPEG) brush using surface initiated atom transfer radical polymerization (SI-ATRP) on PDMS substrates. The PDMS substrates were first oxidized in H(2)SO(4)/H(2)O(2) solution to transform the Si-CH(3) groups on their surfaces into Si-OH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and PolyPEG was finally grafted onto the PDMS surface via copper-mediated ATRP. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the PolyPEG brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS-PolyPEG surface were examined by contact angle measurements. Anti-adhesion properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS-PolyPEG surface exhibited durable wettability and stability, as well as significantly anti-adhesion properties, compared with native PDMS surfaces. Additionally, our results present possible uses for the PDMS-PolyPEG surface as adhesion barriers and anti-fouling or functional surfaces in biomedical applications.

Folate-decorated hybrid polymeric nanoparticles for chemically and physically combined paclitaxel loading and targeted delivery.

In this study, folate-functionalized hybrid polymeric nanoparticles (NPs) were prepared as carriers of low water solubility paclitaxel for tumor targeting, which were composed of monomethoxy-poly(ethylene glycol)-b-poly(lactide)-paclitaxel (MPEG-PLA-paclitaxel) and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-folate (TPGS-FOL). NPs with various weight ratios of MPEG-PLA-paclitaxel and TPGS-FOL were prepared using a solvent extraction/evaporation method, which can also physically encapsulate paclitaxel. The size, size distribution, surface charge, and morphology of the drug-loaded NPs were characterized using a Zetasizer Nano ZS, scanning electron microscope (SEM), and atomic force microscopy (AFM). The encapsulation and drug loading efficiencies of these polymeric NPs are analyzed using high-performance liquid chromatography (HPLC) at 227 nm. The combination of covalent coupling and physical encapsulation is found to improve the loading of paclitaxel in NPs greatly. The in vitro antitumor activity of the drug-loaded NPs is assessed using a standard method of transcriptional and translational (MTT) assays against HeLa and glioma C6 cells. When the cells were exposed to NPs with the same paclitaxel weights, cell viability decreases in relation to the increase in TPGS-FOL in drug-loaded NPs. To investigate drug-loaded NP cellular uptake, the fluorescent dye coumarin-6 is utilized as a model drug and enveloped in NPs with 0 or 50% TPGS-FOL. Confocal laser scanning microscopy (CLSM) analysis shows that cellular uptake is lower for coumarin-6-loaded NPs with 0% TPGS-FOL than those with 50% TPGS-FOL. However, no difference for NIH 3T3 cells with normally expressed folate receptors is found. Results from in vitro antitumor activity and cellular uptake assay demonstrate that folic acid promotes drug-loaded NP cellular uptake through folate receptor-mediated endocytosis (RME). All of these results demonstrate that folate-decorated hybrid polymeric NPs are potential carriers for tumor-targeted drug delivery.