The strigolactone receptor DWARF14 regulates flowering time in Arabidopsis.

Multiple plant hormones, including strigolactone (SL), play key roles in regulating flowering time. The Arabidopsis (Arabidopsis thaliana) DWARF14 (AtD14) receptor perceives SL and recruits F-box protein MORE AXILLARY GROWTH2 (MAX2) and the SUPPRESSOR OF MAX2-LIKE (SMXL) family proteins. These interactions lead to the degradation of the SMXL repressor proteins, thereby regulating shoot branching, leaf shape, and other developmental processes. However, the molecular mechanism by which SL regulates plant flowering remains elusive. Here, we demonstrate that intact strigolactone biosynthesis and signaling pathways are essential for normal flowering in Arabidopsis. Loss-of-function mutants in both SL biosynthesis (max3) and signaling (Atd14 and max2) pathways display earlier flowering, whereas the repressor triple mutant smxl6/7/8 (s678) exhibits the opposite phenotype. Retention of AtD14 in the cytoplasm leads to its inability to repress flowering. Moreover, we show that nuclear-localized AtD14 employs dual strategies to enhance the function of the AP2 transcription factor TARGET OF EAT1 (TOE1). AtD14 directly binds to TOE1 in an SL-dependent manner and stabilizes it. In addition, AtD14-mediated degradation of SMXL7 releases TOE1 from the repressor protein, allowing it to bind to and inhibit the FLOWERING LOCUS T (FT) promoter. This results in reduced FT transcription and delayed flowering. In summary, AtD14 perception of SL enables the transcription factor TOE1 to repress flowering, providing insights into hormonal control of plant flowering.

The value of shear wave elasticity and shear wave dispersion imaging to evaluate the viscoelasticity of renal parenchyma in children with glomerular diseases.

BACKGROUND: To study the value of shear wave elasticity and shear wave dispersion imaging to evaluate the viscoelasticity of renal parenchyma in children with glomerular diseases. METHODS: Forty-three children with glomerular diseases were prospectively evaluated by shear wave elasticity (SWE) and shear wave dispersion imaging (SWD); 43 healthy volunteers served as the control group. The shear wave velocities (SWV) and the dispersion slopes were measured at the upper, middle, and lower poles of both kidneys. The analysis of mean SWV and mean dispersion slope in control and patient groups was used to further evaluate the value of SWE and SWD in the viscoelasticity of renal parenchyma in children with glomerular disease. RESULTS: The mean SWV in children with glomerular disease was higher than that in the healthy control group (1.61 ± 0.09 m/s vs. 1.43 ± 0.07 m/s, p < 0.001). Compared with healthy group, the mean dispersion slope in children with glomerular disease was significantly increased (13.5 ± 1.39 (m/s)/kHz vs. 12.4 ± 1.40 (m/s)/kHz, p < 0.001). Correlation analysis showed absence of correlation between the SWV and dispersion slope of occult blood, serum creatinine, 24-h urine protein, blood albumin, BMI and ROI box depth of children with glomerular disease. CONCLUSIONS: The present study shows that it is feasible to use SWE and SWD to evaluate the difference of viscoelasticity of the renal parenchyma between healthy children and those with glomerular disease.

Development and evaluation of an artificial intelligence system for children intussusception diagnosis using ultrasound images.

Accurate identification of intussusception in children is critical for timely non-surgical management. We propose an end-to-end artificial intelligence algorithm, the Children Intussusception Diagnosis Network (CIDNet) system, that utilizes ultrasound images to rapidly diagnose intussusception. 9999 ultrasound images of 4154 pediatric patients were divided into training, validation, test, and independent reader study datasets. The independent reader study cohort was used to compare the diagnostic performance of the CIDNet system to six radiologists. Performance was evaluated using, among others, balance accuracy (BACC) and area under the receiver operating characteristic curve (AUC). The CIDNet system performed the best in diagnosing intussusception with a BACC of 0.8464 and AUC of 0.9716 in the test dataset compared to other deep learning algorithms. The CIDNet system compared favorably with expert radiologists by outstanding identification performance and robustness (BACC:0.9297; AUC:0.9769). CIDNet is a stable and precise technological tool for identifying intussusception in ultrasound scans of children.

Effect of L-cysteine treatment to induce postharvest disease resistance of Monilinia fructicola in plum fruits and the possible mechanisms involved.

Plum is an important stone fruit in China, but the fruit is easily perishable and susceptible to infection by pathogens. Traditionally, synthetic fungicides are used to control diseases. However, the side effects of fungicides should not be ignored. Cysteine, generally recognized as safe (GRAS) amino acid, has been reported to play roles in the plant abiotic stress response, but little is known about the role of cysteine to control postharvest diseases in fruits. Therefore, this study was designed to investigate the effect of L-cysteine treatment on control of postharvest brown rot in artificially inoculated plum fruits and the possible biocontrol mechanisms involved. Postharvest plum fruits were inoculated with 1, 10, 100 and 1000 mg L-1 L-cysteine. 100 mg L-1 L-cysteine treatment effectively controlled brown rot in artificially inoculated plum fruits by inducing resistance. Furthermore, 100 mg L-1 L-cysteine treatment increased the activities of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH), enhanced the content of NADPH of the pentose phosphate pathway, as well as improved the contents of H2O2 and some amino acids in the artificially inoculated plum fruits. 100 mg L-1 L-cysteine treatment also elevated the antioxidant content (AsA, GSH) and the antioxidant enzymes activities (APX, GR, MDAR, DHAR) of the ascorbate-glutathione (AsA-GSH) pathway. The protective effects of L-cysteine treatment on postharvest plum fruits likely be due to activating some defense-related responses of the fruit against infection. L-cysteine treatment is a safe promising method for controlling postharvest brown rot in plum fruits.

Transcriptional regulatory mechanism of a variant transcription factor CsWRKY23 in citrus fruit resistance to Penicillium digitatum.

As the most productive fruit in the world, there is a lack of research on disease resistance mechanisms in citrus. WRKY transcription factors are mediators of disease resistance in plants. In this research, CsWRKY23, which could respond to exogenous salicylic acid (SA) was identified. As a variant WRKY, the transient overexpression of CsWRKY23 in citrus peel enhanced the resistance to Penicillium digitatum. The potential targets of CsWRKY23 were identified by using DNA affinity purification sequencing (DAP-seq). In combination with RNA sequencing (RNA-seq) data, 48 direct target genes of CsWRKY23 were identified. In addition, five genes for EMSA and dual-luciferase report system analysis were selected and the results showed that CsWRKY23 activate CsAAE12, CsRbohD, CsSARD1, CsWRKY22 and CsIQM6 expressions. Further analysis revealed that CsWRKY23 contributed to SA synthesis pathway, reactive oxygen species (ROS) accumulation, and cell wall strengthening. This study presented a possible regulatory network for disease resistance involving the CsWRKY23.

Activation of the phenylpropanoid pathway in Citrus sinensis collapsed vesicles during segment drying revealed by physicochemical and targeted metabolomics analysis.

Segment drying is a common internal physiological disorder in citrus fruit, and vesicles get granulated or collapsed. This study aimed to probe whether and how the phenylpropanoid metabolism changes in vesicles during collapse of blood orange (Citrus sinensis cv. Tarocco). Vesicle collapse led to a decrease in the content of nutrients and flavonoids, while an increase in lignin content. This disorder was further associated with the increasing enzyme activities and gene expression levels of both the general phenylpropanoid pathway and branch pathway of lignin synthesis, while decreasing enzyme activities and gene expression levels of branch pathway of flavonoids synthesis. Targeted metabolomics analysis of 14 metabolites of the lignin pathway revealed that lignin precursors were accumulated in collapsed vesicles. We provide solid evidence that phenylpropanoid metabolism could be activated, and, intriguingly, metabolic flux may be shuttled to lignin precursors synthesis rather than flavonoids synthesis in vesicles during collapse of blood orange.

Evaluation of renal parenchyma stiffness in children with nephropathy by shear wave elastography: A systematic review and meta-analysis.

BACKGROUND: The role of shear wave elastography (SWE) in assessing renal parenchymal stiffness in children with nephropathy is obscure. This systematic review and meta-analysis investigated this issue. MATERIALS AND METHODS: PubMed, Embase, Web of Science, and the Cochrane Library databases were searched for studies evaluating renal parenchyma stiffness in children with nephropathy by SWE from inception to October 2021. The search was not limited by language. Two investigators independently screened the literature and extracted data. Any discrepancies were resolved via discussion with the senior professor. Study quality was assessed by the Newcastle-Ottawa Scale and the standardized mean difference of shear wave velocity (SWV) for the evaluation of renal parenchyma stiffness was determined. RESULTS: Eight studies involving a total of 496 children with nephropathy and 353 healthy children were selected. Eight studies used SWV as parameters of renal parenchyma stiffness. The SWV was not significantly different in children with renal lesion than in those without renal lesion, with a standardized mean difference of 0.49 (95% confidence level, -0.40 to 1.39, p = 0.28). There was a high heterogeneity between studies. CONCLUSION: Although there was significant difference in SWE of renal parenchyma between controls and patients in each study we included, statistical differences were not seen after results of all research were amalgamated due to different diseases with different pathomechanisms. SWE could be used to evaluate renal parenchymal stiffness in children with kidney disease after more well-designed and high-quality studies with a large sample size will be performed in the future.

Two-dimensional speckle tracking echocardiography demonstrates improved myocardial function after intravenous infusion of bone marrow mesenchymal stem in the X-Linked muscular dystrophy mice.

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) are commonly used in regenerative medicine. However, it is not clear whether transplantation of BMSCs can improve cardiac function of the X-Linked Muscular Dystrophy Mice (mdx) and how to detect it. We aimed to investigate the role of speckle tracking echocardiography (STE) in detecting cardiac function of the BMSCs-transplanted mdx in comparison with the untreated mdx. METHODS: The experimental mice were divided into the BMSCs-transplanted mdx, untreated mdx, and control mice groups (n = 6 per group). The BMSCs were transplanted via tail vein injections into a subset of mdx at 20 weeks of age. After four weeks, the cardiac functional parameters of all the mice in the 3 groups were analyzed by echocardiography. Then, all the mice were sacrificed, and the cardiac tissues were harvested and analyzed by immunofluorescence. The serum biochemical parameters were also analyzed to determine the beneficial effects of BMSCs transplantation. RESULTS: Traditional echocardiography parameters did not show statistically significant differences after BMSCs transplantation for the three groups of mice. In comparison with the control group, mdx showed significantly lower left ventricular (LV) STE parameters in both the long-axis and short-axis LV images (P < 0.05). However, BMSCs-transplanted mdx showed improvements in several STE parameters including significant increases in a few STE parameters (P < 0.05). Immunofluorescence staining of the myocardium tissues showed statistically significant differences between the mdx and the control mice (P < 0.05), and the mdx transplanted with BMSCs demonstrated significantly improvement compared with the untreated mdx (P < 0.05). CONCLUSION: This study demonstrated that the early reduction in the LV systolic and diastolic function in the mdx were accurately detected by STE. Furthermore, our study demonstrated that the transplantation of BMSCs significantly improved myocardial function in the mdx.

Low and high storage temperature inhibited the coloration of mandarin fruit (Citrus unshiu Marc.) with different mechanism.

BACKGROUND: Peel color regulated by pigment metabolism is one of the most crucial indicators affecting the commodity values of citrus fruit. Storage temperature is a vital environmental factor that regulates the fruit pigmentation. RESULTS: Results showed that the peel coloring process was significantly inhibited when mandarin fruit were stored at 5 and 32 °C with normal coloring at 25 °C as the control. However, the inhibitive mechanisms of 5 and 32 °C storage were different. At 5 °C, higher levels of CcNYC and CcCHL2 were detected, which indicated that 5 °C induces the circulation of chlorophyll rather than inhibits chlorophyll degradation. CcPSY2, CcCHYB, and CcZEP exhibited higher expression levels in fruit stored at 5 °C, which accelerated the accumulation of carotenoids. In fruit stored at 32 °C, CcNYC, CcPAO, and CcCHL2 exhibited lower expression levels than those fruit stored at 5 °C, and the expressions of CcPSY2, CcCHYB, and CcZEP were down regulated, implying the carotenoid synthesis was suppressed. CONCLUSION: Storage at 5 °C inhibited the postharvest coloring of mandarin fruit mainly by activating the cycle of chlorophyll, although it promotes the accumulation of carotenoids at the same time, but chlorophyll covers the color of carotenoids. Storage at 32 °C inhibited mandarin fruit coloring mainly by inhibiting the degradation of chlorophyll. Compared with the change of individual chlorophyll or carotenoid content, the change of the ratio of chlorophyll and carotenoid had a more important role in the coloration of mandarin fruit. This research offers valuable details for understanding the effect of temperature on the coloring process of postharvest citrus fruit. © 2022 Society of Chemical Industry.

CsWRKY25 Improves Resistance of Citrus Fruit to Penicillium digitatum via Modulating Reactive Oxygen Species Production.

WRKY transcription factors (TFs) play crucial roles in the regulation of biotic stress. Citrus is the most productive fruit in the world. It is of great value to investigate the regulatory molecular mechanism of WRKYs in improving disease resistance. In this research, the transcription level of CsWRKY25 was upregulated in P. digitatum infected citrus peel, and CsWRKY25 activated the expression of three target genes (RbohB, RbohD, and PR10). Besides, the Agrobacterium-mediated transient overexpression of CsWRKY25 has also been shown to enhance resistance to P. digitatum in citrus, and caused the accumulation of hydrogen peroxide and lignin. The accumulation of ROS also activated the antioxidant system, the catalase (CAT), peroxidase (POD), and cinnamyl alcohol dehydrogenase (CAD) genes were significant upregulated, leading to activation of antioxidant enzymes. In addition, the up-regulated expression of MPK5 and MPK6 genes suggested that the regulatory role of CsWRKY25 might be related to the phosphorylation process. In conclusion, CsWRKY25 could enhance the resistance to P. digitatum via modulating ROS production and PR genes in citrus peel.

Changes in biochemical properties and pectin nanostructures of juice sacs during the granulation process of pomelo fruit (Citrus grandis).

Postharvest granulation is a severe physiological disorder in citrus fruit that may be related to pectin metabolism. This study was designed to analyze the changes in fruit quality and pectin metabolism of pomelo fruit during granulation from expansion, gelation to lignification. Fruit quality showed a decrease starting from the gelation stage. Contents of water-soluble pectin, chelate-soluble pectin, sodium carbonate-soluble pectin and calcium, and activity of pectin methylesterase increased, while polygalacturonase activity decreased upon granulation. Atomic force microscopy analysis showed that both length and width of those three types of pectin molecules increased during granulation, accompanied by the decrease of linear structure molecules of pectin and the increase of pectin polymers, and multi-branched pectin tending to form cross-linked structure. Complex network of pectin might be remodeled during granulation process that immobilized the free water in juice sacs and induced the gelation occurrence, further promoted the granulation process.

Involvement of CsWRKY70 in salicylic acid-induced citrus fruit resistance against Penicillium digitatum.

Penicillium digitatum causes serious losses in postharvest citrus fruit. Exogenous salicylic acid (SA) can induce fruit resistance against various pathogens, but the mechanism remains unclear. Herein, a transcriptome-based approach was used to investigate the underlying mechanism of SA-induced citrus fruit resistance against P. digitatum. We found that CsWRKY70 and genes related to methyl salicylate (MeSA) biosynthesis (salicylate carboxymethyltransferase, SAMT) were induced by exogenous SA. Moreover, significant MeSA accumulation was detected in the SA-treated citrus fruit. The potential involvement of CsWRKY70 in regulating CsSAMT expression in citrus fruit was studied. Subcellular localization, dual luciferase, and electrophoretic mobility shift assays and an analysis of transient expression in fruit peel revealed that the nucleus-localized transcriptional activator CsWRKY70 can activate the CsSAMT promoter by recognizing the W-box element. Taken together, the findings from this study offer new insights into the transcriptional regulatory mechanism of exogenous SA-induced disease resistance in Citrus sinensis fruit.

Biocontrol ability and action mechanism of Metschnikowia citriensis against Geotrichum citri-aurantii causing sour rot of postharvest citrus fruit.

This study investigated the biocontrol efficiency of Metschnikowia citriensis strain FL01 against Geotrichum citri-aurantii, and evaluated possible mechanisms. The results showed that M. citriensis could effectively control the development of sour rot, and significantly inhibit the mycelial growth and spore germination of G. citri-aurantii. The population dynamics results and Scanning electron microscopy (SEM) analysis indicated that M. citriensis could rapidly colonize wounds and tightly adhere to the surface of the wounds to compete with G. citri-aurantii for nutrition and space. M. citriensis also showed the biofilm formation action in vitro. The response of G. citri-aurantii to different components of M. citriensis culture showed that only the yeast cells but not the extracellular metabolites and the volatile organic compounds (VOCs) exhibited inhibitory effect on the growth of G. citri-aurantii. M. citriensis adhered to the hyphae of G. citri-aurantii loosely and sparsely, and the production of lytic enzymes ß-1, 3-glucanase (GLU) and Chitinase (CHI) could not be induced by G. citri-auranti. Iron affected the pulcherrimin pigment production and antagonism of M. citriensis indicating iron depletion as the most important antagonistic mechanism. Besides, M. citriensis also induced resistance of fruit against sour rot. These results suggested that M. citriensis could be used as the potential alternative of fungicides to control postharvest pathogens on citrus fruit.

Proline Increases Pigment Production to Improve Oxidative Stress Tolerance and Biocontrol Ability of Metschnikowia citriensis.

Utilizing antagonistic yeasts is a promising approach for managing postharvest decay of fruits. However, it is well established that various severe stresses encountered in the environment and production process cause the intracellular reactive oxygen species (ROS) accumulation in yeast cells, resulting in cell damage and loss of vitality. Here, proline has been shown to function as a cell protectant and inducer of biofilm formation able to increase the oxidative stress tolerance and the biocontrol ability of the antagonistic yeast Metschnikowia citriensis. Addition of proline to M. citriensis cells induced a significant rise in superoxide dismutase (SOD) and catalase (CAT) activity in the early and late stages of oxidative stress, respectively, and increased the maroon pigment production that directly reduced intracellular iron content and indirectly diminished intracellular ROS levels and thus inhibited ROS- and iron-induced apoptosis. Treating cells with iron chelator tropolone yielded similar results. Pigment production induced by proline also enhanced the capability of biofilm formation of M. citriensis. These results suggested an important role for pigment of M. citriensis in response to oxidative stress. The abilities of proline to scavenge intracellular ROS and inhibit apoptosis, increase pigment production, and promote biofilm formation contribute to the improvements in oxidative stress tolerance and biocontrol efficacy of M. citriensis.

Variations in chlorophyll and carotenoid contents and expression of genes involved in pigment metabolism response to oleocellosis in citrus fruits.

Yellow or green spots related to pigment changes found at the early stage of oleocellosis can cause severe economic damage. However, little information exists on pigment changes during oleocellosis development, so this study investigated the main changes in chlorophyll and carotenoid metabolites and related gene expression. Among the variations, the increased contents of chlorophyll a and b, and decreased concentrations of lutein, ß-cryptoxanthin, zeaxanthin, violaxanthin, α-carotene and ß-carotene were responsible for chlorophyll and carotenoid changes, respectively. Regarding gene expression, the up-regulated genes, magnesium chelatase subunit H (MgCh), magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase 1/2 (MPEC1/2), protochlorophyllide reductase a, chloroplastic 1/2 (PORA1/2) and chlorophyllide a oxygenase (CAO), regarding chlorophyll synthesis as well as the down-regulated genes, phytoene synthase (PSY), phytoene dehydrogenase (PDS), lycopene ß-cyclase (LCYb), and zeaxanthin epoxidase 1/2 (ZEP 1/2) and the up-regulated genes (+)-abscisic acid 8'-hydroxylase 1/2 (ABA-HX 1/2), regarding carotenoid metabolism, constituted the major variations in oleocellosis peels.

Control of Citrus Post-harvest Green Molds, Blue Molds, and Sour Rot by the Cecropin A-Melittin Hybrid Peptide BP21.

In this study, the activity of the cecropin A-melittin hybrid peptide BP21 (Ac-FKLFKKILKVL-NH2) in controlling of citrus post-harvest green and blue molds and sour rot and its involved mechanism was studied. The minimum inhibitory concentrations of BP21 against Penicillium digitatum, Penicillium italicum, and Geotrichum candidum were 8, 8, and 4 µmol L-1, respectively. BP21 could inhibit the growth of mycelia, the scanning electron microscopy results clearly showed that the mycelia treated with BP21 shrank, formed a rough surface, became distorted and collapsed. Fluorescent staining with SYTOX Green (SG) indicated that BP21 could disintegrate membranes. Membrane permeability parameters, including extracellular conductivity, the leakage of potassium ions, and the release of cellular constituents, visibly increased as the BP21 concentration increased. Gross and irreversible damage to the cytoplasm and membranes was observed. There was a positive correlation between hemolytic activity and the concentration of BP21. These results suggest peptide BP21 could be used to control citrus post-harvest diseases.

Peptidomics of potato protein hydrolysates: implications of post-translational modifications in food peptide structure and behaviour.

Post-translational modifications (PTMs) often occur in proteins and play a regulatory role in protein function. There is an increasing interest in the bioactivity of food protein-derived peptides, but the occurrence of PTMs and their influence on food peptide structure and behaviour remain largely unknown. In this study, the shotgun-based peptidomics strategy was used to identify the occurrence of PTMs in peptides generated from potato protein hydrolysis using digestive proteases. Diverse PTMs were found in the potato peptides, including acetylation of lysine, N-terminal of proteins and peptides, C-terminal amidation, de-amidation of asparagine/glutamine, methylation and trimethylation, methionine oxidation and N-terminal pyro-glutamyl residue formation. The modifications may have been formed naturally or as a result of chemical reactions during isolation and enzymatic processing of the potato proteins. Most of the PTMs were calculated to decrease the isoelectric point and increase molecular hydrophobicity of the peptides, which will influence their bioactivity while also potentially altering their solubility in an aqueous environment. This is the first study to unravel that food-derived peptides can be widely modified by PTMs associated with notable changes in peptide chemical properties. The findings have broader implications on the bioavailability, biomolecular interactions and biological activities of food peptides.

Structural Basis of Bioactivity of Food Peptides in Promoting Metabolic Health.

Bioactive peptides have many structural features that enable them to become functional in controlling several biological processes in the body, especially those related to metabolic health. This chapter provides an overview of the multiple targets of food-derived peptides against metabolic health problems (e.g., hypertension, dyslipidemia, hyperglycemia, oxidative stress) and discusses the importance of structural chemistry in determining the bioactivities of peptides and protein hydrolysates.

Analysis of changes in volatile constituents and expression of genes involved in terpenoid metabolism in oleocellosis peel.

Oleocellosis is a serious physiological disorder in citrus fruit that mainly results in appearance and quality deterioration. It has been well established that the occurrence of oleocellosis is highly correlated with the release of peel oil from citrus fruit, while there is little information on the dynamic changes in the content of the volatile constituents and the expression of genes involved in terpenoid metabolism during oleocellosis development. In the present research, large changes in the volatile profiles and gene expression in terpenoid metabolism were observed in oleocellosis peels compared to healthy ones. Among volatiles, the decreased contents of α-pinene, d-limonene, ß-myrcene, linalool, ß-caryophyllene, α-terpineol, nonanal, neryl acetate and (-)-carvone played a major role in these changes. For gene expressions in terpenoid metabolism, the up-regulated genes aldehyde dehydrogenase (NAD+) (ALDH) and the down-regulated genes ß-caryophyllene synthase 1 (BCS1), α-terpineol synthase 2 (TES2) and myrcene synthase (MS) were the main differences in oleocellosis peels.