Background UV-B signaling in plants is mediated by UVR8, which interacts with transcriptional factors to induce root morphogenesis. However, research on the downstream molecules of UVR8 signaling in roots is still scarce. As a wide range of functional cytoskeletons, how actin filaments respond to UV-B-induced root morphogenesis has not been reported. The aim of this study was to investigate the effect of actin filaments on root morphogenesis under UV-B and hydrogen peroxide exposure in Arabidopsis. Results A Lifeact-Venus fusion protein was used to stain actin filaments in Arabidopsis. The results showed that UV-B inhibited hypocotyl and root elongation and caused an increase in H2O2 content only in the root but not in the hypocotyl. Additionally, the actin filaments in hypocotyls diffused under UV-B exposure but were gathered in a bundle under the control conditions in either Lifeact-Venus or uvr8 plants. Exogenous H2O2 inhibited root elongation in a dose-dependent manner. The actin filaments changed their distribution from filamentous to punctate in the root tips and mature regions at a lower concentration of H2O2 but aggregated into thick bundles with an abnormal orientation at H2O2 concentrations up to 2 mM. In the root elongation zone, the actin filament arrangement changed from lateral to longitudinal after exposure to H2O2. Actin filaments in the root tip and elongation zone were depolymerized into puncta under UV-B exposure, which showed the same tendency as the low-concentration treatments. The actin filaments were hardly filamentous in the maturation zone. The dynamics of actin filaments in the uvr8 group under UV-B exposure were close to those of the control group. Conclusions The results indicate that UV-B inhibited Arabidopsis hypocotyl elongation by reorganizing actin filaments from bundles to a loose arrangement, which was not related to H2O2. UV-B disrupted the dynamics of actin filaments by changing the H2O2 level in Arabidopsis roots. All these results provide an experimental basis for investigating the interaction of UV-B signaling with the cytoskeleton.
As an allohexaploid plant, common wheat has a complex gene structure, making it difficult to study its gene function. Virus-induced gene silencing (VIGS) is an important tool for the rapid analysis of plant gene function. In this study, the gene silencing system, namely, barley stripe mosaic virus (BSMV)-VIGS induced by BSMV was used to silence the wheat phytoene desaturase (TaPDS) and actin depolymerization factor (TaADF7) genes and determine the effect of gene silencing on wheat. TaPDS was used as an indicator gene to determine the feasibility of VIGS system, while TaADF7 was used as a test gene to determine its effect on wheat growth. Results showed that the leaves of tobacco and wheat were bleached by the mixture of pCaBS-α, pCaBS-β, and pCaBS-γ::TaPDS, indicating that the TaPDS gene was silenced, and the bleached leaves had physiological activity as determined by trypan blue staining. Therefore, the VIGS system was efficient and available. After the tobacco was treated with pCaBS-α, pCaBS-β, and pCaBS-γ::TaADF7, the viral suspension was obtained. The expression of TaADF7 gene was downregulated after wheat leaves were infected by friction, indicating that the expression of TaADF7 was silenced. Laser confocal scanning microscopy showed that the silencing of TaADF7 enhanced the fluorescence of microfilament skeleton in mesophyll protoplasts and significantly reduced the plant height. Results showed that TaADF7 affected cell division and plant growth by inhibiting microfilament depolymerization. In conclusion, the BSMV-VIGS system was used to silence wheat TaPDS and TaADF7 genes.Bleaching phenomenon was observed in wheat leaves after TaPDS silencing. After TaADF7 silencing, microfilaments in wheat mesophyll cells gathered into coarse bundles, which affected the dynamics of microfilaments and inhibited plant growth.
Ultraviolet (UV)-B is a component of sunlight and shows a significant effect on DNA damage, which can be regulated by proliferating cell nuclear antigen (PCNA). The role of TaPCNA in wheat (Triticum aestivum L.) programmed cell death (PCD) under UV-B has not been investigated previously. Here, we explored the function of TaPCNA in wheat exposed to UV-B utilising Barley Stripe Mosaic Virus-virus-induced gene silencing (VIGS). The results showed that the expression of TaPCNA was downregulated, and curly wheat leaves with several spots were determined by VIGS. The growth rate and mesophyll cell length were significantly inhibited after TaPCNA was silenced. The activity of superoxide dismutase and the contents of soluble sugar and soluble protein decreased, whereas the activities of peroxidase and catalase and malondialdehyde content increased in TaPCNA-silenced and UV-B treatment groups. DNA laddering and propidium iodide staining results showed that DNA fragments and micronucleus accumulated after TaPCNA silencing with or without UV-B. Thus, TaPCNA participates in plant growth and DNA damage and PCD under UV-B. This study suggests an idea for the exploration of the function of certain genes in such complex wheat genomes and offers a theoretical basis to improve wheat agronomic traits.
Plants adjust their shoot growth to acclimate to changing environmental factors, such as to enhanced Ultraviolet-B (UV-B) radiation. However, people have ignored that plant roots can also respond to UV-B light. Here, we find the morphology curled wheat roots under UV-B radiation, that we call, “bending roots.” The curly region is the transition zone of the root after observed at the cellular level. After exposed to enhanced UV-B radiation for 2 d (10.08 KJ/m2/d), cell size decreased and actin filaments gathered in wheat roots. We also find that H2O2 production increased and that content of the indole-3-acetic acid (IAA) increased remarkably. The pharmacological experiment revealed that actin filaments gathered and polymerized into bundles in the wheat root cells after irrigated H2O2 and IAA. These results indicated that actin filaments changed their distribution and formed the “bending root,” which was related to H2O2 production and increase in IAA. Overall, actin filaments in wheat root cells could be a subcellular target of UV-B radiation, and its disruption determines root morphology.
Negative pressure wound therapy (NPWT) is a popular treatment to heal infected wounds. This meta‐analysis aimed to determine if NPWT was more effective than conventional wound dressings for surgical site infections (SSI) in varied orthopaedic surgeries. Literature was retrieved from seven electronic databases (Medline, Web of Science, PubMed, Embase, Google Scholar, Cochrane Library, and CNKI). Randomised control trials (RCT) and retrospective cohort studies (RS) involving arthroplasty, fracture, and spinal surgery were extracted. SSI was our primary outcome, while total complications and length of hospital stay were secondary outcomes. We carried out the risk of bias assessment and meta‐analysis using the Cochrane Risk of Bias 2.0 tool and Stata 17.0. Among the 798 studies retrieved, 18 of them met our inclusion criteria. We identified 13 RCTs and 5 RSs. The results of meta‐analysis showed that the incidence of SSI in the NPWT group was significantly lower relative to the control group (OR = 0.60, 95% CI 0.47 to 0.77, P < 0.001). Subgroup analyses revealed that the incidences of SSI involving arthroplasty, fracture, and spinal surgery in the NPWT group accounted for 46%, 69%, and 37% relative to the control group, respectively. The incidence of SSI in RS (OR = 0.27, 95% CI 0.13 to 0.56) was significantly lower than that in RCT (OR = 0.69, 95% CI 0.54 to 0.90) (P = 0.02). Moreover, patients in the NPWT group had a lower total complication rate (OR = 0.51, 95% CI 0.34 to 0.76) and shorter hospital stays (SMD = −0.42, 95% CI −0.83 to −0.02), although high heterogeneity existed. NPWT may be an efficient alternative to help prevent the incidence of SSI and total complications as well as achieved shorten hospital stay in varied orthopaedic surgeries. The rational use of NPWT should be based on the presence of patients' clinical conditions and relevant risk factors.
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