ERF54 regulates cold tolerance in Rosa multiflora through DREB/COR signalling pathways.

Ethylene-responsive factors (ERFs) participate in a wide range of physiological and biological processes. However, many of the functions of ERFs in cold stress responses remain unclear. We, therefore, characterised the cold responses of RmERF54 in Rosa multiflora, a rose-related cold-tolerant species. Overexpression of RmERF54, which is a nuclear transcription factor, increases the cold resistance of transgenic tobacco and rose somatic embryos. In contrast, virus-induced gene silencing (VIGS) of RmERF54 increased cold susceptibility of R. multiflora. The overexpression of RmERF54 resulted in extensive transcriptional reprogramming of stress response and antioxidant enzyme systems. Of these, the levels of transcripts encoding the PODP7 peroxidase and the cold-related COR47 protein showed the largest increases in the somatic embryos with ectopic expression of RmERF54. RmERF54 binds to the promoters of the RmPODP7 and RmCOR47 genes and activates expression. RmERF54-overexpressing lines had higher antioxidant enzyme activities and considerably lower levels of reactive oxygen species. Opposite effects on these parameters were observed in the VIGS plants. RmERF54 was identified as a target of Dehydration-Responsive-Element-Binding factor (RmDREB1E). Taken together, provide new information concerning the molecular mechanisms by which RmERF54 regulates cold tolerance.

Transcriptome Landscape Analyses of the Regulatory Network for Zygotic Embryo Development in Paeonia ostii.

Paeonia ostii is a worldwide ornamental flower and an emerging oil crop. Zyotic embryogenesis is a critical process during seed development, and it can provide a basis for improving the efficiency of somatic embryogenesis (SE). In this study, transcriptome sequencing of embryo development was performed to investigate gene expression profiling in P. ostii and identified Differentially expressed genes (DEGs) related to transcription factors, plant hormones, and antioxidant enzymes. The results indicated that IAA (Indole-3-acetic acid), GA (Gibberellin), BR (Brassinosteroid) and ETH (Ethylene) were beneficial to early embryonic morphogenesis, while CTK (Cytokinin) and ABA (Abscisic Acid) promoted embryo morphogenesis and maturation. The antioxidant enzymes' activity was the highest in early embryos and an important participant in embryo formation. The high expression of the genes encoding fatty acid desaturase was beneficial to fast oil accumulation. Representative DEGs were selected and validated using qRT-PCR. Protein-protein interaction network (PPI) was predicted, and six central node proteins, including AUX1, PIN1, ARF6, LAX3, ABCB19, PIF3, and PIF4, were screened. Our results provided new insights into the formation of embryo development and even somatic embryo development in tree peonies.

A conservative pathway for coordination of cell wall biosynthesis and cell cycle progression in plants.

The mechanism that coordinates cell growth and cell cycle progression remains poorly understood; in particular, whether the cell cycle and cell wall biosynthesis are coordinated remains unclear. Recently, cell wall biosynthesis and cell cycle progression were reported to respond to wounding. Nonetheless, no genes are reported to synchronize the biosynthesis of the cell wall and the cell cycle. Here, we report that wounding induces the expression of genes associated with cell wall biosynthesis and the cell cycle, and that two genes, AtMYB46 in Arabidopsis thaliana and RrMYB18 in Rosa rugosa, are induced by wounding. We found that AtMYB46 and RrMYB18 promote the biosynthesis of the cell wall by upregulating the expression of cell wall-associated genes, and that both of them also upregulate the expression of a battery of genes associated with cell cycle progression. Ultimately, this response leads to the development of curled leaves of reduced size. We also found that the coordination of cell wall biosynthesis and cell cycle progression by AtMYB46 and RrMYB18 is evolutionarily conservative in multiple species. In accordance with wounding promoting cell regeneration by regulating the cell cycle, these findings also provide novel insight into the coordination between cell growth and cell cycle progression and a method for producing miniature plants.

RrMYB5- and RrMYB10-regulated flavonoid biosynthesis plays a pivotal role in feedback loop responding to wounding and oxidation in Rosa rugosa.

Flavonoids play critical roles in plant responses to various stresses. Few studies have been reported on what the mechanism of activating flavonoid biosynthesis in plant responses to wounding and oxidation is. In this study, flavonoid metabolites and many MYB transcript factors from Rosa rugosa were verified to be induced by wounding and oxidation. RrMYB5 and RrMYB10, which belong to PA1- and TT2-type MYB TFs, respectively, showed extremely high induction. Overexpression of RrMYB5 and RrMYB10 resulted in an increased accumulation of proanthocyanidins in R. rugosa and tobacco by promoting the expression of flavonoid structural genes. Transcriptomic analysis of the transgenic plants showed that most genes, involved in wounding and oxidation response and ABA signalling modulation, were up-regulated by the overexpression of RrMYB10, which was very much similar to that observed in RrANR and RrDFR overexpression transgenics. RrMYB5 and RrMYB10 physically interacted and mutually activated each other's expressions. They solely or synergistically activated the different sets of flavonoid pathway genes in a bHLH TF EGL3-independent manner. Eventually, the accumulation of proanthocyanidins enhanced plant tolerance to wounding and oxidative stresses. Therefore, RrMYB5 and RrMYB10 regulated flavonoid synthesis in feedback loop responding to wounding and oxidation in R. rugosa. Our study provides new insights into the regulatory mechanisms of flavonoid biosynthesis by MYB TFs and their essential physiological functions in plant responses to wounding and oxidative stresses.

Overexpression of particular MADS-box transcription factors in heat-stressed plants induces chloroplast biogenesis in petals.

Chloroplasts convert solar energy into biologically useful forms of energy by performing photosynthesis. Although light and particular genes are known to promote chloroplast development, little is known about the mechanisms that regulate the tissue-specificity and cell-specificity of chloroplast biogenesis. Thus, the mechanisms that determine whether non-photosynthetic plastids rather than chloroplasts develop in petals remain largely unexplored. Although heat stress is known to inhibit photosynthesis, we do not know whether heat stress affects chloroplast biogenesis. Here, we report that heat stress up-regulates the expression of chlorophyll biosynthesis-related genes and promotes chloroplasts biogenesis in petals overexpressing SOC1 (suppressor of overexpression of CO) and novel SOC1-like genes. We also found that these specific MADS-box transcription factors are present in most photosynthetic eukaryotes and that the expression of more than one homolog is observed in chloroplast-containing tissues. These findings not only provide novel insights into the tissue specificity of chloroplast biogenesis and a method for producing green petals but also are consistent with heat stress influencing chloroplast biogenesis in higher plants.

Identification of PP2Cs in six rosaceae species highlights RcPP2C24 as a negative regulator in rose drought tolerance.

Drought is a major environmental stress that limits plant growth, so it's important to identify drought-responsive genes to understand the mechanism of drought response and breed drought-tolerant roses. Protein phosphatase 2C (PP2C) plays a crucial role in plant abiotic stress response. In this study, we identified 412 putative PP2Cs from six Rosaceae species. These genes were divided into twelve clades, with clade A containing the largest number of PP2Cs (14.1%). Clade A PP2Cs are known for their important role in ABA-mediated drought stress response; therefore, the analysis focused on these specific genes. Conserved motif analysis revealed that clade A PP2Cs in these six Rosaceae species shared conserved C-terminal catalytic domains. Collinearity analysis indicated that segmental duplication events played a significant role in the evolution of clade A PP2Cs in Rosaceae. Analysis of the expression of 11 clade A RcPP2Cs showed that approximately 60% of these genes responded to drought, high temperature, and salt stress. Among them, RcPP2C24 exhibited the highest responsiveness to both drought and ABA. Furthermore, overexpression of RcPP2C24 significantly reduced drought tolerance in transgenic tobacco by increasing stomatal aperture after exposure to drought stress. The transient overexpression of RcPP2C24 weakened the dehydration tolerance of rose petal discs, while its silencing increased their dehydration tolerance. In summary, our study identified PP2Cs in six Rosaceae species and highlighted the negative role of RcPP2C24 on rose's drought tolerance by inhibiting stomatal closure. Our findings provide valuable insights into understanding the mechanism behind rose's response to drought.

PoARRO-1 regulates adventitious rooting through interaction with PoIAA27b in Paeonia ostii.

Adventitious root (AR) formation is a limiting factor in the vegetative propagation of tree peony (Paeonia suffruticosa Andr.). PoARRO-1, which encodes an auxin oxidase involved in AR formation, plays a role in the root development of P. ostii, but its associated molecular regulatory mechanisms are not yet understood. In this study, we examined the role of PoARRO-1 in AR formation in P. ostii. The overexpression of PoARRO-1 in P. ostii test-tube plantlets led to a notable enhancement in both the rooting rate and the average number of ARs in vitro, as well as increased activities of peroxidase (POD), superoxide dismutase (SOD), and indoleacetic acid oxidase (IAAO). PoARRO-1 was involved in the conversion of IAA-Asp and IAA-Glu to OxIAA and promoted IAA oxidation. RNA sequencing analysis revealed that PoARRO-1 overexpression led to upregulation of enzyme activity, auxin metabolism related genes. Further analyses showed that PoARRO-1 interacted with the 1-175 aa position of PoIAA27b to regulate the formation of ARs. We therefore propose that PoARRO-1 interacts with PoIAA27b to promote AR formation, and it may be useful targets for enhancing the in vitro propagation of P. ostii.

Effect of Different Monochromatic LEDs on the Environmental Adaptability of Spathiphyllum floribundum and Chrysanthemum morifolium.

Light-emitting diodes (LEDs) can be programmed to provide specialized light sources and spectra for plant growth. UV-A (397.6 nm), blue (460.6 nm), green (520.7 nm), and red (661.9 nm) LED light sources were used to study the effects of different monochromatic lights on the growth, antioxidant system, and photosynthetic characteristics of Spathiphyllum floribundum 'Tian Jiao' (a shade-loving species) and Chrysanthemum morifolium 'Huang Xiu Qiu' (a sun-loving species). This research revealed that green and blue light could enhance the morphological indicators, Chl a/b, photosynthetic electron transfer chain performance, and photosystem activity of S. floribundum, blue and red light could enhance the solution protein, Chl a, and photosynthetic electron transfer chain performance of C. morifolium, red and UV-A light viewed the highest SOD and CAT activities of S. floribundum (275.56 U·min·g-1; 148.33 U·min·g-1) and C. morifolium (587.03 U·min·g-1; 98.33 U·min·g-1), respectively. Blue and green light were more suitable for the growth and development of the shade-loving plant S. floribundum, while red and blue light were more suitable for the sun-loving plant C. morifolium. UV-A light could be used for their stress research. The research revealed the different adaptation mechanism of different plants to light environmental conditions.

Postoperative hemorrhage after biomedical glue sling technique in microvascular decompression for vertebrobasilar artery-associated cranial nerve diseases: A retrospective study of 14 cases.

Background: The biomedical glue sling technique is a convenient and effective method for vertebrobasilar artery-associated cranial nerve diseases but postoperative hemorrhage is poorly understood. Methods: We retrospectively reviewed 14 of 1157 patients associated with cranial nerve diseases who were subjected to the biomedical glue sling technique in microvascular decompression at our hospital from January 2015 to January 2020. Results: There were 14 patients with cranial nerve diseases included in this study. A clinical diagnosis of postoperative hemorrhage was made after an average of 41.75 h (ranging between 0.5 and 95 h). A cerebellopontine angle hemorrhage was presented in 5 patients, while basal ganglia hemorrhage was observed in 2 patients. Both a cerebellopontine angle and brainstem hemorrhage was seen in 1 patient. Distal supratentorial subdural hemorrhage was recorded in 6 patients. The correlation coefficient was -0.1601 (p = 0.7094) between the standard deviation of systolic blood pressure and the Hemphill Score, -0.2422 (p = 0.5633) between the coefficient of variation of systolic blood pressure and the Hemphill Score, and -0.0272 (p = 0.9489) between the range of systolic blood pressure and the Hemphill Score. Conclusions: The incidence of postoperative hemorrhage after MVD with the biomedical glue sling technique is higher than with traditional MVD and most cases have a favorable prognosis. Postoperative symptoms are the main area of concern and changes in symptoms usually suggest the occurrence of hemorrhage. Several factors, including surgical procedures, the release of CSF, and blood pressure might be associated with hemorrhaging. We still believe such a technique is an efficient approach to treating complicated cranial nerve diseases.

Homeostatic regulation of flavonoid and lignin biosynthesis in phenylpropanoid pathway of transgenic tobacco.

Flavonoids and lignin consist of a large number of secondarymetabolites which are derived from the phenylpropanoid pathway, and they act as a significant role in plant growth, development, and stress response. However, few reports have documented that how different subbranches of phenylpropanoid metablolic pathway mutually interact. In Arabidopsis, AtCPC (AtCAPRICE) is known to play a negative role in anthocyanin accumulation. Nonetheless, whether AtCPC could control the biosynthesis of lignin is largely unknown. Additionally, whether the RrFLS and RrANR, flavonol synthase and anthocyanidin reductase, from Rosa rugosa regulate different branches of phenylpropanoid pathway is unclear. Here, we performed a series of transgenic experiments with short life cycle tobacco and RNA-Seq analysis. Finally, a series of assays related to biological, physiological, and phenotypic characteristics were undertaken. Our results indicated that ectopic expression of AtCPC in tobacco not only decreased the flavonoid compound accumulation, but also up-regulated several lignin biosynthetic genes, and significantly increased the accumulation of lignin. Our results also revealed that although they respectively improved the flavonol and proanthocyanidin contents, the overexpression of RrFLS and RrANR plays positive roles in lignin biosynthesis in transgenic tobacco plants. Our findings provide a novel insight into the mechanism underlying homeostatic regulation of flavonoid and lignin biosynthesis in phenylpropanoid pathway of plants.

Brassinolide soaking and preharvest UV-B radiation influence the shelf life of small black bean sprouts.

This study explored the effects of brassinolide (BR) soaking, preharvest ultraviolet-B (UV-B) radiation, and their combined treatments on physiological characteristics, chlorophyll fluorescence, and quality of small black bean sprouts during storage. Results indicated that the combined treatments significantly enhanced contents of flavone, free amino acid, and photosynthetic pigment, and activities of phenylalanine ammonia lyase (PAL) and 2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging in sprouts stored for 5 days compared with BR treatment alone. The combined treatments significantly increased total phenols content and PAL activity, and reduced malonaldehyde content in sprouts compared with UV-B radiation alone. The inhibitory effect of BR or UV-B on fluorescence of photosystem II was weakened by their combined treatments. Comprehensive analysis indicated that the combined treatments could be used to maintain postharvest small black bean sprouts with high levels of nutritional ingredients by probably keeping high photosynthetic capacity, PAL activity, and DPPH radical scavenging rate in sprouts.

Ameliorating Effect of Microvascular Decompression on Patients with Coexistence of Hemifacial Spasm and Glossopharyngeal Neuralgia: A Retrospective Study.

OBJECTIVE: Microvascular decompression (MVD) has been widely accepted for treating hemifacial spasm (HFS) and glossopharyngeal neuralgia (GN); an effective surgical treatment of coexistent HFS and GN still remains to be determined, however. In this paper we discuss the operative strategy of MVD for patients with coexistent HFS and GN. METHODS: This was a retrospective study. All cases of HFS with or without GN at China-Japan Friendship Hospital from January 2014 to June 2016 have been included. All patients underwent MVD and have been followed up for an average of 1.5 years. RESULTS: A total of 5375 cases of HFS were included, wherein 8 cases coexist with GN. Eight patients had same offending vessel(s) compressing the root entry zone of glossopharyngeal nerve and facial nerve. Posterior inferior cerebellar artery was identified as at least 1 of the offending arteries in all 8 patients. After MVD, spasm ceased in all 8 cases, with 7 cases ceasing immediately and 1 within 2 months. Pain disappeared also in all cases, with 7 cases immediately and 1 case after 4 days. No recurrence or complication was observed during the follow-ups. CONCLUSIONS: HFS combined with ipsilateral GN was rare. MVD could be performed to effectively relieve nerve root compression and associated symptoms for coexistent HFS and GN. Sufficient exposure of root entry zones of both nerves and fully decompression of offending blood vessels and exploratory sequences of different nerve roots are critical points for improving operative effect and reducing complications.

The Divergence of Flowering Time Modulated by FT/TFL1 Is Independent to Their Interaction and Binding Activities.

FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) proteins share highly conserved amino acid residues but they play opposite regulatory roles in promoting and repressing the flowering response, respectively. Previous substitution models and functional analysis have identified several key amino acid residues which are critical for the promotion of flowering. However, the precise relationship between naturally occurring FT/TFL1 homologs and the mechanism of their role in flowering is still unclear. In this study, FT/TFL1 homologs from eight Rosaceae species, namely, Spiraea cantoniensis, Pyracantha fortuneana, Photinia serrulata, Fragaria ananassa, Rosa hybrida, Prunus mume, Prunus persica and Prunus yedoensis, were isolated. Three of these homologs were further characterized by functional analyses involving site-directed mutagenesis. The results showed that these FT/TFL1 homologs might have diverse functions despite sharing a high similarity of sequences or crystal structures. Functional analyses were conducted for the key FT amino acids, Tyr-85 and Gln-140. It revealed that TFL1 homologs cannot promote flowering simply by substitution with key FT amino acid residues. Mutations of the IYN triplet motif within segment C of exon 4 can prevent the FT homolog from promoting the flowering. Furthermore, physical interaction of FT homologous or mutated proteins with the transcription factor FD, together with their lipid-binding properties analysis, showed that it was not sufficient to trigger flowering. Thus, our findings revealed that the divergence of flowering time modulating by FT/TFL1 homologs is independent to interaction and binding activities.

Overexpression of Rosa rugosa anthocyanidin reductase enhances tobacco tolerance to abiotic stress through increased ROS scavenging and modulation of ABA signaling.

Anthocyanidin reductase (ANR) is a key enzyme involved in the biosynthesis of proanthocyanidins (PAs) and plays a role in the plant stress response. However, the mechanism by which ANR confers stress tolerance in plants is not understood. Here, we report the isolation of RrANR, the homologous gene from rose, and NtABF, an ABA-response related transcription factor gene from tobacco. These genes were characterized regarding their functions in stress responses through the use of transgenic, transcriptomic and physiological analyses. Over-expression of RrANR in tobacco resulted in an increased accumulation of both PAs and abscisic acid (ABA), and also enhanced stress tolerance. Transcriptomic analysis of these transgenic tobacco lines indicated that RrANR overexpression induced global transcriptomic changes, including these involved in oxidation/reduction, hormone response and secondary metabolism. Genes related to ABA biosynthesis and reactive oxygen species (ROS)-scavenging were up-regulated in RrANR transgenic lines, and these effects were phenocopied by the direct treatment of tobacco plants with PAs and ABA. Transcriptomic data from each of these treatments identified the upregulation of a putative NtABF. Furthermore, the up-regulation of NtABF in RrANR transformants or in PAs- and ABA-treated tobacco plants was associated with enhanced stress tolerance. Overexpression of NtABF in transgenic tobacco mimicked the effects of RrANR-transgenic plants with regard to the up-regulation of ROS-scavenging genes and an increase in oxidative tolerance. Taken together, our findings indicate that overexpression of RrANR results in an increase in plant tolerance to oxidative stress via increased scavenging of ROS and modulation of the ABA signaling pathway.

Disequilibrium of Flavonol Synthase and Dihydroflavonol-4-Reductase Expression Associated Tightly to White vs. Red Color Flower Formation in Plants.

Flower color is the main character throughout the plant kingdom. Though substantial information exists regarding the structural and regulatory genes involved in anthocyanin and flavonol biosynthesis, little is known that what make a diverse white vs. red color flower in natural species. Here, the contents of pigments in seven species from varied phylogenetic location in plants with red and white flowers were determined. Flavonols could be detected in red and white flowers, but anthocyanins were almost undetectable in the white cultivar. Comparisons of expression patterns of gene related to the flavonoid biosynthesis indicated that disequilibrium expression of flavonol synthase (FLS) and dihydroflavonol-4-reductase (DFR) genes determined the accumulation of flavonols and anothcyanins in both red and white flowers of seven species. To further investigate the role of such common regulatory patterns in determining flower color, FLS genes were isolated from Rosa rugosa (RrFLS1), Prunus persica (PpFLS), and Petunia hybrida (PhFLS), and DFR genes were isolated from Rosa rugosa (RrDFR1) and Petunia hybrida (PhDFR). Heterologous expression of the FLS genes within tobacco host plants demonstrated conservation of function, with the transgenes promoting flavonol biosynthesis and inhibiting anthocyanin accumulation, so resulting in white flowers. Conversely, overexpression of DFR genes in tobacco displayed down-regulation of the endogenous NtFLS gene, and the promotion of anthocyanin synthesis. On this basis, we propose a model in which FLS and DFR gene-products compete for common substrates in order to direct the biosynthesis of flavonols and anthocyanins, respectively, thereby determining white vs. red coloration of flowers.

Facilitating role of biogenetic schwertmannite in the reduction of Cr(VI) by sulfide and its mechanism.

The efficient conversion of Cr(VI) to Cr(III) has attracted an increasing concern in recent years owing to its threat to the environment. In the present paper, the catalytic role of biogenetic schwertmannite in the reduction of Cr(VI) by sulfide and its mechanism were investigated under different conditions through batch experiments. The results demonstrated that schwertmannite markedly accelerated the removal of Cr(VI) by sulfide, and the rates of the reaction were enhanced by 11, 8 and 6 times, respectively at pH 7.5, 8.0 and 8.8 as compared with control (no schwertmannite). In addition, the conversion of Cr(VI) into Cr(III) increased with schwertmannite loading and temperature. However, the facilitating role of schwertmannite in the reduction of Cr(VI) by sulfide was markedly suppressed by an introduction of F(-), a complex agent for Fe(III). It is concluded that the catalysis of schwertmannite results from the activated Fe(III) on the surface of schwertmannite, serving as a "bridge" in the transportation of electrons between sulfide and Cr(VI), and leading to the improving reduction of Cr(VI) by sulfide.