The molecular mechanism of ABA‐promoted anthocyanin accumulation and fruit coloration is less known. Here, an apple bZIP transcription factor MdbZIP44 was identified to be a positive regulator in ...ABA‐promoted anthocyanin accumulation by interacting with MdMYB1 and enhancing its binding capacity to the promoters of downstream target genes. MdBT2 decreased ABA‐promoted anthocyanin accumulation by degrading MdbZIP44 protein.
Phytohormone abscisic acid (ABA) induces anthocyanin biosynthesis; however, the underlying molecular mechanism is less known. In this study, we found that the apple MYB transcription factor MdMYB1 activated anthocyanin biosynthesis in response to ABA. Using a yeast screening technique, we isolated MdbZIP44, an ABA‐induced bZIP transcription factor in apple, as a co‐partner with MdMYB1. MdbZIP44 promoted anthocyanin accumulation in response to ABA by enhancing the binding of MdMYB1 to the promoters of downstream target genes. Furthermore, we identified MdBT2, a BTB protein, as an MdbZIP44‐interacting protein. A series of molecular, biochemical, and genetic analysis suggested that MdBT2 degraded MdbZIP44 protein through the Ubiquitin‐26S proteasome system, thus inhibiting MdbZIP44‐modulated anthocyanin biosynthesis. Taken together, we reveal a novel working mechanism of MdbZIP44‐mediated anthocyanin biosynthesis in response to ABA.
Summary
MYB transcription factors (TFs) have been demonstrated to play diverse roles in plant growth and development through interaction with basic helix‐loop‐helix (bHLH) TFs. MdbHLH33, an apple ...bHLH TF, has been identified as a positive regulator in cold tolerance and anthocyanin accumulation by activating the expressions of MdCBF2 and MdDFR. In the present study, a MYB TF MdMYB308L was found to also positively regulate cold tolerance and anthocyanin accumulation in apple. We found that MdMYB308L interacted with MdbHLH33 and enhanced its binding to the promoters of MdCBF2 and MdDFR. In addition, an apple RING E3 ubiquitin ligase MYB30‐INTERACTING E3 LIGASE 1 (MdMIEL1) was identified to be an MdMYB308L‐interacting protein and promoted the ubiquitination degradation of MdMYB308L, thus negatively regulated cold tolerance and anthocyanin accumulation in apple. These results suggest that MdMYB308L acts as a positive regulator in cold tolerance and anthocyanin accumulation in apple by interacting with MdbHLH33 and undergoes MdMIEL1‐mediated protein degradation. The dynamic change in MYB‐bHLH protein complex seems to play a key role in the regulation of plant growth and development.
SUMMARY
Jasmonate (JA) induces the biosynthesis of anthocyanin and proanthocyanidin. MdMYB9 is essential for modulating the accumulation of both anthocyanin and proanthocyanidin in apple, but the ...molecular mechanism for induction of anthocyanin and proanthocyanidin biosynthesis by JA is unclear. In this study, we discovered an apple telomere‐binding protein (MdTRB1) to be the interacting protein of MdMYB9. A series of biological assays showed that MdTRB1 acted as a positive modulator of anthocyanin and proanthocyanidin accumulation, and is dependent on MdMYB9. MdTRB1 interacted with MdMYB9 and enhanced the activation activity of MdMYB9 to its downstream genes. In addition, we found that the JA signaling repressor MdJAZ1 interacted with MdTRB1 and interfered with the interaction between MdTRB1 and MdMYB9, therefore negatively modulating MdTRB1‐promoted biosynthesis of anthocyanin and proanthocyanidin. These results show that the JAZ1–TRB1–MYB9 module dynamically modulates JA‐mediated accumulation of anthocyanin and proanthocyanidin. Taken together, our data further expand the functional study of TRB1 and provide insights for further studies of the modulation of anthocyanin and proanthocyanidin biosynthesis by JA.
Significance Statement
The apple telomere‐binding protein MdTRB1 positively modulates JA‐mediated accumulation of anthocyanin and proanthocyanidin by interacting with MdMYB9 and enhancing the activation activity of MdMYB9 to MdANS and MdANR. The JA signaling repressor MdJAZ1 interacted with MdTRB1 and interfered with the interaction between MdTRB1 and MdMYB9, therefore negatively modulating MdTRB1‐promoted biosynthesis of anthocyanin and proanthocyanidin.
It is known that ethylene signaling is involved in the regulation of the salt stress response. However, the molecular mechanism of ethylene‐regulated salt stress tolerance remains largely unclear. In ...this study, an apple NAM ATAF CUC transcription factor, MdNAC047, was isolated and functionally characterized to be involved in ethylene‐modulated salt tolerance. MdNAC047 gene was significantly induced by salt treatment and its overexpression conferred increased tolerance to salt stress and facilitated the release of ethylene. Quantitative real‐time‐PCR analysis demonstrated that overexpression of MdNAC047 increased the expression of ethylene‐responsive genes. Electrophoretic mobility shift assay, yeast one‐hybrid and dual‐luciferase assays suggested that MdNAC047 directly binds to the MdERF3 (ETHYLENE RESPONSE FACTOR) promoter and activates its transcription. In addition, genetic analysis assays indicated that MdNAC047 regulates ethylene production at least partially in an MdERF3‐dependent pathway. Overall, we found a novel ‘MdNAC047‐MdERF3‐ethylene‐salt tolerance’ regulatory pathway, which provide new insight into the link between ethylene and salt stress.
Wounding stress leads to leaf senescence. However, the underlying molecular mechanism has not been elucidated. In this study, we investigated the role of the MdVQ10-MdWRKY75 module in wound-induced ...leaf senescence. MdWRKY75 was identified as a key positive modulator of wound-induced leaf senescence by activating the expression of the senescence-associated genes MdSAG12 and MdSAG18. MdVQ10 interacted with MdWRKY75 to enhance MdWRKY75-activated transcription of MdSAG12 and MdSAG18, thereby promoting leaf senescence triggered by wounding. In addition, the calmodulin-like protein MdCML15 promoted MdVQ10-mediated leaf senescence by stimulating the interaction between MdVQ10 and MdWRKY75. Moreover, the jasmonic acid signaling repressors MdJAZ12 and MdJAZ14 antagonized MdVQ10-mediated leaf senescence by weakening the MdVQ10-MdWRKY75 interaction. Our results demonstrate that the MdVQ10-MdWRKY75 module is a key modulator of wound-induced leaf senescence, and provides insights into the mechanism of leaf senescence caused by wounding.
Glioblastoma multiforme (GBM) is an aggressive form of brain tumours that remains incurable despite recent advances in clinical treatments. Previous studies have focused on sub‐categorizing patient ...samples based on clustering various transcriptomic data. While functional genomics data are rapidly accumulating, there exist opportunities to leverage these data to decipher glioma‐associated biomarkers. We sought to implement a systematic approach to integrating data from high throughput CRISPR‐Cas9 screening studies with machine learning algorithms to infer a glioma functional network. We demonstrated the network significantly enriched various biological pathways and may play roles in glioma tumorigenesis. From densely connected glioma functional modules, we further predicted 12 potential Wnt/β‐catenin signalling pathway targeted genes, including AARSD1, HOXB5, ITGA6, LRRC71, MED19, MED24, METTL11B, SMARCB1, SMARCE1, TAF6L, TENT5A and ZNF281. Cox regression modelling with these targets was significantly associated with glioma overall survival prognosis. Additionally, TRIB2 was identified as a glioma neoplastic cell marker in single‐cell RNA‐seq of GBM samples. This work establishes novel strategies for constructing functional networks to identify glioma biomarkers for the development of diagnosis and treatment in clinical practice.
The MYB transcription factor family is one of the largest transcriptional factor families in plants and plays a multifaceted role in plant growth and development. However, MYB transcription factors ...involved in pathogen resistance in apple remain poorly understood.
We identified a new MYB family member from apple, and named it MdMYB30. MdMYB30 was localized to the nucleus, and was highly expressed in young apple leaves. Transcription of MdMYB30 was induced by abiotic stressors, such as polyethylene glycol and abscisic acid. Scanning electron microscopy and gas chromatograph-mass spectrometry analyses demonstrated that ectopically expressing MdMYB30 in Arabidopsis changed the wax content, the number of wax crystals, and the transcription of wax-related genes. MdMYB30 bound to the MdKCS1 promoter to activate its expression and regulate wax biosynthesis. MdMYB30 also contributed to plant surface properties and increased resistance to the bacterial strain Pst DC3000. Furthermore, a virus-based transformation in apple fruits and transgenic apple calli demonstrated that MdMYB30 increased resistance to Botryosphaeria dothidea. Our findings suggest that MdMYB30 plays a vital role in the accumulation of cuticular wax and enhances disease resistance in apple.
MdMYB30 bound to the MdKCS1 gene promoter to activate its transcription and regulate cuticular wax content and composition, which influenced the surface properties and expression of pathogenesis-related genes to resistance against pathogens. MdMYB30 appears to be a crucial element in the formation of the plant cuticle and confers apple with a tolerance to pathogens.
Human infections with zoonotic coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV, have raised great public health concern ...globally. Here, we report a novel bat-origin CoV causing severe and fatal pneumonia in humans.
We collected clinical data and bronchoalveolar lavage (BAL) specimens from five patients with severe pneumonia from Wuhan Jinyintan Hospital, Hubei province, China. Nucleic acids of the BAL were extracted and subjected to next-generation sequencing. Virus isolation was carried out, and maximum-likelihood phylogenetic trees were constructed.
Five patients hospitalized from December 18 to December 29, 2019 presented with fever, cough, and dyspnea accompanied by complications of acute respiratory distress syndrome. Chest radiography revealed diffuse opacities and consolidation. One of these patients died. Sequence results revealed the presence of a previously unknown β-CoV strain in all five patients, with 99.8% to 99.9% nucleotide identities among the isolates. These isolates showed 79.0% nucleotide identity with the sequence of SARS-CoV (GenBank NC_004718) and 51.8% identity with the sequence of MERS-CoV (GenBank NC_019843). The virus is phylogenetically closest to a bat SARS-like CoV (SL-ZC45, GenBank MG772933) with 87.6% to 87.7% nucleotide identity, but is in a separate clade. Moreover, these viruses have a single intact open reading frame gene 8, as a further indicator of bat-origin CoVs. However, the amino acid sequence of the tentative receptor-binding domain resembles that of SARS-CoV, indicating that these viruses might use the same receptor.
A novel bat-borne CoV was identified that is associated with severe and fatal respiratory disease in humans.
Inspired by the 2D bilayer lipid membranes in nature, a unique supramolecular “push–pull” synergetic strategy toward self‐assembled 2D organic crystals (2DOCs) is proposed in this work, which can ...effectively suppress the interlayer 3D stacking while maintaining the assembly of the intralayer for 2D growth. For this purpose, a model molecule PF‐Py consisting of a planar supramolecular “attractor” and a nonplanar steric “repellor” is designed for the solution self‐assembly process. Well‐defined 2DOCs including crystal nanosheets and millimeter‐sized crystal films with layered amphiphile‐like packing are obtained, which is analogical to the cell membranes of living organisms. Thanks to the special packing mode, the 2DOCs have fascinating integrated photoelectric property, with high mobility of 7.8 × 10−2 cm2 V−1 s−1, high crystalline state photoluminescence quantum yield of 55%, and superior deep‐blue laser characteristics with a low threshold of 5.51 µJ cm−2. This supramolecular synergetic strategy advances the design of 2D organic semiconductor crystals for high performance optoelectronics.
Rational molecular design strategy toward 2D organic crystals (2DOCs) is necessary but rare. Here, a novel supramolecular “push–pull” strategy to guide the molecular design by integrating a planar segment and a nonplanar group into one molecule is developed. Thanks to the synergetic effect of the two groups, size controllable 2DOCs with superior integrated photoelectric property are realized.
The understanding of adsorption of proteins and nucleic acids on clay minerals and their interactions is important in biological applications for soil ecosystem, the earth's biochemical evolution and ...origin of life, delivery of drug, etc. This review summarizes adsorption of proteins and nucleic acids (DNA, RNA) on natural clay minerals of layer phyllosilicates such as montmorillonite, kaolinite and illite and their interactions. Recent advances in adsorption mechanisms, adsorption sites and effect of various factors on adsorption are discussed. The interaction mechanisms are suggested to be cation exchange, electrostatic interactions, hydrophobic/hydrophilic interactions, ligand exchange, cation bridge, water bridge, hydrogen bond and van der Waals forces. The physical and chemical characteristics of clay minerals and proteins and nucleic acids are mainly responsible for the absorption of these biomolecules by clay minerals besides external conditions, for instance pH and ion strength of absorption solution. Finally, comments on the perspectives and potential benefits of the studies on adsorption of proteins and nucleic acids on clay minerals and their interactions are also made.
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•Reviewing recent studies on adsorption of protein, DNA and RNA onto clay minerals•Discussing adsorption sites of clay minerals for protein, DNA and RNA•Providing insight into interactions between protein, DNA, RNA and clay minerals•Remarking the factors affecting adsorption of protein, DNA and RNA by clay minerals•Recommending future work for tackling existing problems and finding new applications
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