TSPO-induced degradation of the ethylene receptor RhETR3 promotes salt tolerance in rose (Rosa hybrida).

The gaseous plant hormone ethylene regulates plant development, growth, and responses to stress. In particular, ethylene affects tolerance to salinity; however, the underlying mechanisms of ethylene signaling and salt tolerance are not fully understood. Here, we demonstrate that salt stress induces the degradation of the ethylene receptor ETHYLENE RESPONSE 3 (RhETR3) in rose (Rosa hybrid). Furthermore, the TspO/MBR (Tryptophan-rich sensory protein/mitochondrial benzodiazepine receptor) domain-containing membrane protein RhTSPO interacted with RhETR3 to promote its degradation in response to salt stress. Salt tolerance is enhanced in RhETR3-silenced rose plants but decreased in RhTSPO-silenced plants. The improved salt tolerance of RhETR3-silenced rose plants is partly due to the increased expression of ACC SYNTHASE1 (ACS1) and ACS2, which results in an increase in ethylene production, leading to the activation of ETHYLENE RESPONSE FACTOR98 (RhERF98) expression and, ultimately accelerating H2O2 scavenging under salinity conditions. Additionally, overexpression of RhETR3 increased the salt sensitivity of rose plants. Co-overexpression with RhTSPO alleviated this sensitivity. Together, our findings suggest that RhETR3 degradation is a key intersection hub for the ethylene signalling-mediated regulation of salt stress.

Exploring the Landscape of the PP7 Virus-like Particle for Peptide Display.

Self-assembling virus-like particles (VLPs) can tolerate a wide degree of genetic and chemical manipulation to their capsid protein to display a foreign molecule polyvalently. We previously reported the successful incorporation of foreign peptide sequences in the junction loop and onto the C-terminus of PP7 dimer VLPs, as these regions are accessible for surface display on assembled capsids. Here, we report the implementation of a library-based approach to test the assembly tolerance of PP7 dimer capsid proteins to insertions or terminal extensions of randomized 15-mer peptide sequences. By performing two iterative rounds of assembly-based selection, we evaluated the degree of favorability of all 20 amino acids at each of the 15 randomized positions. Deep sequencing analysis revealed a distinct preference for the inclusion of hydrophilic peptides and negatively charged amino acids (Asp and Glu) and the exclusion of positively charged peptides and bulky and hydrophobic amino acid residues (Trp, Phe, Tyr, and Cys). Within the libraries tested here, we identified 4000 to 22,000 unique 15-mer peptide sequences that can successfully be displayed on the surface of the PP7 dimer capsid. Overall, the use of small initial libraries consisting of no more than a few million members yielded a significantly larger number of unique and assembly-competent VLP sequences than have been previously characterized for this class of nucleoprotein particle.

Ononin ameliorates inflammation and cartilage degradation in rat chondrocytes with IL-1ß-induced osteoarthritis by downregulating the MAPK and NF-κB pathways.

BACKGROUND: Osteoarthritis (OA) treatment aims to improve inflammation and delay cartilage degeneration. However, there is no effective strategy presently available. Ononin, a representative isoflavone glycoside component extracted from natural Chinese herbs, exerts anti-inflammatory and proliferative effects. However, the therapeutic effect of ononin on chondrocyte inflammation remains unclear. METHODS: In this study, we explored the therapeutic effect and potential mechanism of ononin in OA by establishing an interleukin-1 beta (IL-1ß)-induced chondrocyte inflammation model. RESULTS: Our results verified that ononin alleviated the IL-1ß-induced decrease in chondrocyte viability, attenuated the overexpression of the inflammatory factors tumour necrosis factor α (TNF-α) and interleukin 6 (IL-6), and simultaneously inhibited the expression of cartilage extracellular matrix (ECM)-degrading enzymes such as matrix metalloproteinase-13 (MMP-13). Furthermore, the decomposition of Collagen II protein could be alleviated in the OA model by ononin. Finally, ononin improved chondrocyte inflammation by downregulating the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signalling pathways. CONCLUSION: Our findings suggested that ononin could inhibit the IL-1ß-induced proinflammatory response and ECM degradation in chondrocytes by interfering with the abnormal activation of the MAPK and NF-κB pathways, indicating its protective effect against OA.

Ethylene-regulated asymmetric growth of the petal base promotes flower opening in rose (Rosa hybrida).

Flowers are the core reproductive structures and key distinguishing features of angiosperms. Flower opening to expose stamens and gynoecia is important in cases where pollinators much be attracted to promote cross-pollination, which can enhance reproductive success and species preservation. The floral opening process is accompanied by the coordinated movement of various floral organs, particularly petals. However, the mechanisms underlying petal movement and flower opening are not well understood. Here, we integrated anatomical, physiological, and molecular approaches to determine the petal movement regulatory network using rose (Rosa hybrida) as a model. We found that PETAL MOVEMENT-RELATED PROTEIN1 (RhPMP1), a homeodomain transcription factor (TF) gene, is a direct target of ETHYLENE INSENSITIVE3, a TF that functions downstream of ethylene signaling. RhPMP1 expression was upregulated by ethylene and specifically activated endoreduplication of parenchyma cells on the adaxial side of the petal (ADSP) base by inducing the expression of RhAPC3b, a gene encoding the core subunit of the Anaphase-Promoting Complex. Cell expansion of the parenchyma on the ADSP base was subsequently enhanced, thus resulting in asymmetric growth of the petal base, leading to the typical epinastic movement of petals and flower opening. These findings provide insights into the pathway regulating petal movement and associated flower-opening mechanisms.�.

Comparison of the clinical effects of computer-assisted and traditional techniques in bilateral total knee arthroplasty: A meta-analysis of randomized controlled trials.

BACKGROUND: It is unclear whether there are individual differences in the long-term efficacy of computer-assisted and traditional total knee arthroplasty. The purpose of this study was to perform a meta-analysis comparing the same individuals undergoing computer-assisted and traditional total knee arthroplasty separately to determine whether computer-assisted total knee arthroplasty can provide better lower extremity radiographic results and clinical outcomes. METHODS: We searched literatures to identify relevant randomized controlled trials comparing the effects of computer-assisted and traditional methods in bilateral total knee arthroplasty. After screening, quality evaluation and data extraction according to inclusion and exclusion criteria, the quality and bias risks of the included studies were evaluated. The meta-analysis compared the radiographic results, functional outcomes and complications of the two techniques. RESULTS: Six clinical controlled trials were included, with total of 1098 patients. The meta-analysis showed that the accuracy in terms of the mechanical axis of the lower extremity, the sagittal alignment of the femoral component and the coronal alignment of the tibial component in computer-assisted total knee arthroplasty was significantly better than those in traditional total knee arthroplasty. There were no differences in the functional results, revision rates or aseptic loosening rates between the two techniques. CONCLUSION: After excluding individual differences such as bone development and bone quality, although computer-assisted techniques can better accurately correct the mechanical axis of the lower extremity and the position of prosthesis implantation than traditional techniques, there is no significant difference in the functional results and revision rate of bilateral total knee arthroplasty in the same individual.

Engineering the PP7 Virus Capsid as a Peptide Display Platform.

As self-assembling polyvalent nanoscale structures that can tolerate substantial genetic and chemical modification, virus-like particles are useful in a variety of fields. Here we describe the genetic modification and structural characterization of the Leviviridae PP7 capsid protein as a platform for the presentation of functional polypeptides. This particle was shown to tolerate the display of sequences from 1 kDa (a cell penetrating peptide) to 14 kDa (the Fc-binding double Z-domain) on its exterior surface as C-terminal genetic fusions to the coat protein. In addition, a dimeric construct allowed the presentation of exogenous loops between capsid monomers and the simultaneous presentation of two different peptides at different positions on the icosahedral structure. The PP7 particle is thereby significantly more tolerant of these types of polypeptide additions than Qß and MS2, the other Leviviridae-derived VLPs in common use.

Overexpression of a novel chrysanthemum SUPERMAN-like gene in tobacco affects lateral bud outgrowth and flower organ development.

Previous studies have shown that the SUP genes play important roles in flower development and plant growth and morphogenesis. In this study, we isolated and characterized a SUPERMAN-like gene DgSZFP from chrysanthemum. DgSZFP contains one conserved Cys2/His2-type zinc finger motifs in the N-terminal region and an EAR-box in C-terminus. Its expression was significantly higher in nodes, flower buds, disc stamens, and petals than in the other tissues. Overexpression of DgSZFP in tobacco resulted in enhanced branching, reduced plant height, increased the width of petal tubes, produced the staminoid petals and petaloid stamens in flowers, and enhanced the seed weight and size. In addition, DgSZFP-overexpression tobacco plants accumulated high concentrations of cytokinin and chlorophyll. These results suggest that DgSZFP may be the candidate gene for regulating branching and floral organ development in chrysanthemum.

Overexpression of a novel chrysanthemum NAC transcription factor gene enhances salt tolerance in tobacco.

The plant-specific NAC (for NAM, ATAF1, 2 and CUC2) transcription factors (TFs) have been implicated in different cellular processes involved in stress responses such as cold, high salinity or drought as well as abscisic acid (ABA) signalling. However, the roles of the chrysanthemum NAC TF genes in plant stress responses are still unclear. A full-length cDNA designated DgNAC1, containing a highly conserved N-terminal DNA-binding NAC domain, has been isolated from chrysanthemum by RACE (rapid amplification of cDNA ends). It encodes a protein of 284 amino acids residues (=~32.9 kDa) and theoretical pI of 7.13. The transcript of DgNAC1 was enriched in roots and flowers than in stems and leaves of the adult chrysanthemum plants. The gene expression was strongly induced by ABA, NaCl, drought and cold treatment in the seedlings. Subcellular localization revealed that DgNAC1:GFP fusion protein was preferentially distributed to nucleus. To assess whether DgNAC1 is a practically useful target gene for improving the stress tolerance of chrysanthemum, we ectopically over-expressed the full-length DgNAC1 cDNA in tobacco and found that the 35S:DgNAC1 transgenic tobacco exhibited a markedly increased tolerance to salt. Despite this increased salt stress tolerance, the transgenic tobacco showed no detectable phenotype defects under normal growth conditions. These results proposed that DgNAC1 is appropriate for application in genetic engineering strategies aimed at improving salt stress tolerance in chrysanthemum.

Isolation and functional characterization of DgZFP: a gene encoding a Cys2/His2-type zinc finger protein in chrysanthemum.

A Cys2/His2-type zinc finger protein gene, DgZFP, was isolated from chrysanthemum by rapid amplification of cDNA ends (RACE) approach. The DgZFP encodes a protein of 211 amino acids residues with a calculated molecular mass of 22.9 kDa and theoretical isoelectric point is 8.59. DgZFP contains two Cys2/His2-type zinc finger motifs, one nuclear localization domain, one Leu-rich domain, and one ethylene-responsive element-binding factor (ERF)-associated amphiphilic repression (EAR) domain. The transcript of DgZFP was enriched in flowers than in roots, stems, and leaves of the adult chrysanthemum plants. The gene expression was strongly induced by NaCl, drought and cold treatment, and weakly by ABA treatment in the seedlings. Subcellular localization revealed that DgZFP was localized preferentially distributed to nucleus. Overexpression of DgZFP improved salt tolerance and resulted in growth suppression in transgenic tobacco. We argued that DgZFP is a new member of the Cys2/His2-type zinc finger protein genes, and it maybe function as a regulator in response to salt stress in plants.