PEBP4 deficiency aggravates LPS-induced acute lung injury and alveolar fluid clearance impairment via modulating PI3K/AKT signaling pathway.

Acute lung injury (ALI) is a common clinical syndrome, which often results in pulmonary edema and respiratory distress. It has been recently reported that phosphatidylethanolamine binding protein 4 (PEBP4), a basic cytoplasmic protein, has anti-inflammatory and hepatoprotective effects, but its relationship with ALI remains undefined so far. In this study, we generated PEBP4 knockout (KO) mice to investigate the potential function of PEBP4, as well as to evaluate the capacity of alveolar fluid clearance (AFC) and the activity of phosphatidylinositide 3-kinases (PI3K)/serine-theronine protein kinase B (PKB, also known as AKT) signaling pathway in lipopolysaccharide (LPS)-induced ALI mice models. We found that PEBP4 deficiency exacerbated lung pathological damage and edema, and increased the wet/dry weight ratio and total protein concentration of bronchoalveolar lavage fluid (BALF) in LPS-treated mice. Meanwhile, PEBP4 KO promoted an LPS-induced rise in the pulmonary myeloperoxidase (MPO) activity, serum interleuin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α levels, and pulmonary cyclooxygenase-2 (COX-2) expression. Mechanically, PEBP4 deletion further reduced the protein expression of Na+ transport markers, including epithelial sodium channel (ENaC)-α, ENaC-γ, Na,K-ATPase α1, and Na,K-ATPase ß1, and strengthened the inhibition of PI3K/AKT signaling in LPS-challenged mice. Furthermore, we demonstrated that selective activation of PI3K/AKT with 740YP or SC79 partially reversed all of the above effects caused by PEBP4 KO in LPS-treated mice. Altogether, our results indicated the PEBP4 deletion has a deterioration effect on LPS-induced ALI by impairing the capacity of AFC, which may be achieved through modulating the PI3K/AKT pathway.

Pseudomonas protegens volatile organic compounds inhibited brown rot of postharvest peach fruit by repressing the pathogenesis-related genes in Monilinia fructicola.

Brown rot, caused by Monilinia fructicola, is considered one of the devasting diseases of pre-harvest and post-harvest peach fruits, restricting the yield and quality of peach fruits and causing great economic losses to the peach industry every year. Presently, the management of the disease relies heavily on chemical control. In the study, we demonstrated that the volatile organic compounds (VOCs) of endophyte bacterial Pseudomonas protegens QNF1 inhibited the mycelial growth of M. fructicola by 95.35% compared to the control, thereby reducing the brown rot on postharvest fruits by 98.76%. Additionally, QNF1 VOCs severely damaged the mycelia of M. fructicola. RNA-seq analysis revealed that QNF1 VOCs significantly repressed the expressions of most of the genes related to pathogenesis (GO:0009405) and integral component of plasma membrane (GO:0005887), and further analysis revealed that QNF1 VOCs significantly altered the expressions of the genes involved in various metabolism pathways including Amino acid metabolism, Carbohydrate metabolism, and Lipid metabolism. The findings of the study indicated that QNF1 VOCs displayed substantial control efficacy by disrupting the mycelial morphology of M. fructicola, weakening its pathogenesis, and causing its metabolic disorders. The study provided a potential way and theoretical support for the management of the brown rot of peach fruits.

Genome-wide identification and transcriptional analysis of ammonium transporters in Saccharum.

Ammonium transporters (AMTs) are plasma membrane proteins that exclusively transport ammonium/ammonia. It is essential for the nitrogen demand of plantsby AMT-mediated acquisition of ammonium from soils. The molecular characteristics and evolutionary history of AMTs in Saccharum spp. remain unclear. We comprehensively evaluated the AMT gene family in the latest release of the S. spontaneum genome and identified 6 novel AMT genes. These genes belong to 3 clusters: AMT2 (2 genes), AMT3 (3 genes), and AMT4 (one gene). Evolutionary analyses suggested that the S. spontaneum AMT gene family may have expanded via whole-genome duplication events. All of the 6 AMT genes are located on 5 chromosomes of S. spontaneum. Expression analyses revealed that AMT3;2 was highly expressed in leaves and in the daytime, and AMT2;1/3;2/4 were dynamic expressed in different leaf segments, as well as AMT2;1/3;2 demonstrated a high transcript accumulation level in leaves and roots and were significantly dynamic expressed under low-nitrogen conditions. The results suggest the functional roles of AMT genes on tissue expression and ammonium absorption in Saccharum. This study will provide some reference information for further elucidation of the functional mechanism and regulation of expression of the AMT gene family in Saccharum.

Comparative phylogenetic analysis of CBL reveals the gene family evolution and functional divergence in Saccharum spontaneum.

BACKGROUND: The identification and functional analysis of genes that improve tolerance to low potassium stress in S. spontaneum is crucial for breeding sugarcane cultivars with efficient potassium utilization. Calcineurin B-like (CBL) protein is a calcium sensor that interacts with specific CBL-interacting protein kinases (CIPKs) upon plants' exposure to various abiotic stresses. RESULTS: In this study, nine CBL genes were identified from S. spontaneum. Phylogenetic analysis of 113 CBLs from 13 representative plants showed gene expansion and strong purifying selection in the CBL family. Analysis of CBL expression patterns revealed that SsCBL01 was the most commonly expressed gene in various tissues at different developmental stages. Expression analysis of SsCBLs under low K+ stress indicated that potassium deficiency moderately altered the transcription of SsCBLs. Subcellular localization showed that SsCBL01 is a plasma membrane protein and heterologous expression in yeast suggested that, while SsCBL01 alone could not absorb K+, it positively regulated K+ absorption mediated by the potassium transporter SsHAK1. CONCLUSIONS: This study provided insights into the evolution of the CBL gene family and preliminarily demonstrated that the plasma membrane protein SsCBL01 was involved in the response to low K+ stress in S. spontaneum.

Systemic hypoxia potentiates anti-tumor effects of metformin in hepatocellular carcinoma in mice.

Local hypoxia is a universal phenomenon in most solid tumors. The role of local hypoxia in the tumor microenvironment and cancer growth and metastasis has been well established. However, the effect of acute systemic hypoxia (exposing the whole body to 10% O2 environment) on cancer has not yet been investigated. In this study, we investigated the potential effects of acute systemic hypoxia itself and in combination with metformin on hepatocellular carcinoma (HCC) growth and metastasis in a mouse model of HCC. Acute systemic hypoxia significantly decreased tumor volume and weight in H22 tumor-bearing mice. Interestingly, the combined treatment of acute systemic hypoxia and metformin showed a more pronounced effect in reducing tumor volume and weight. Moreover, acute systemic hypoxia and metformin in combination had a potent inhibitory effect on tumor progression. More importantly, the expressions of hypoxia response genes including hypoxia-inducible factor-1 α, vascular endothelial growth factor, and matrix metalloproteinase 2 were significantly decreased in the tumor tissues with combination treatment. Our study demonstrated that acute systemic hypoxia repressed tumor progression of the HCC and potentiated the anti-tumor activities of metformin. This study supports that combination of systemic hypoxia and metformin treatment may represent a novel strategy for HCC.

BML-111, a lipoxin receptor agonist, protects against acute injury via regulating the renin angiotensin-aldosterone system.

BACKGROUND: The renin angiotensin-aldosterone system (RAAS) and lipoxins (LXs) have similar roles in many processes. We previously reported that BML-111, a Lipoxin receptor agonist, inhibited chronic injury hepatic fibrosis by regulating RAAS, but whether LXs are involved in BML-111-mediated protection from acute injury is unclear still. METHODS: We established models of acute liver/lung injury and confirmed them with histopathology and myeloperoxidase (MPO) measurements. BML-111, a lipoxin receptor agonist, was applied to mimic the effects of LXs. The contents and activities of angiotensin converting enzyme(ACE) and angiotensinconverting enzyme 2 (ACE2) were measured through ELISA and activity assay kits respectively. Angiotensin II (AngII), angiotensin-(1-7) (Ang-1-7), AngII type 1 receptor (AT1R), and Mas receptor were quantified with ELISA and Western blot. RESULTS: Models of acute injury were established successfully and BML-111 protected LPS-induced acute lung injury and LPS/D-GalN-induced acute liver injury. BML-111 repressed the activity of ACE, but increased the activity of ACE2. BML-111 decreased the expression levels of ACE, AngII, and AT1R, meanwhile increased the levels of ACE2, Ang-(1-7), and Mas. Furthermore, BOC-2, an inhibitor of lipoxin receptor, reversed all the effects. CONCLUSION: BML-111 could protect against acute injury via regulation RAAS.

BML-111 equilibrated ACE-AngII-AT1R and ACE2-Ang-(1-7)-Mas axis to protect hepatic fibrosis in rats.

BACKGROUND: It was recently reported Lipoxins (LXs) had protective effects on fibrous diseases, and renin-angiotensin-aldosterone system (RAAS) had played vital and bidirectional roles in hepatic fibrosis. In this paper, a hepatic fibrosis model, induced by carbon tetrachloride (CCL4) in rats, was used to observe the relations between RAAS and LXs, as well as to further explore the alternative anti-fibrosis mechanisms of LXs. METHODS: The model was evaluated by morphological observations and biochemical assays. The activities and contents of angiotensin converting enzyme (ACE) and angiotensin converting enzyme 2 (ACE2) were examined through assay kits and ELISA. The expression levels of angiotensinII (AngII), Angiotensin II type 1 receptor (AT1R), angiotensin-(1-7) (Ang-1-7), and Mas were all measured using real time PCR, ELISA, and Western blot. RESULTS: The model was established successfully and BML-111 significantly ameliorated CCL4-induced hepatic fibrosis, including reduction inflammation injury, decrease extracellular matrix deposition, and improvement hepatic functions. Furthermore, BML-111 could obviously decrease not only the activities of ACE but also the expression levels of ACE, AngII,and AT1R, which were induced by CCL4. On the other hand, BML-111 could markedly increase the activities of ACE2, besides the expression levels of ACE2, Ang-(1-7) and Mas. More importantly, BOC-2, a lipoxin A4 receptor blocker, could reverse all these phenomena. CONCLUSIONS: Equilibrating ACE-AngII-AT1R axis and ACE2-Ang-(1-7)-Mas axis mediated the protective effect of BML-111 on hepatic fibrosis in rats.

[Design of portable blood pressure depressor based on slow breathing training].

Clinical studies had demonstrated that slow breathing could lower blood pressure significantly. Based on this knowledge, a portable blood pressure depressor was designed in this study. The device used a miniature variable distance capacitive sensor to collect respiratory signal, an STM32 as the main control chip, a WT588D voice chip to generate voice and music and guide slow breathing, and a 3.5-inch color screen to display breathing state and provide guidance. For patients with difficulty in adapting themselves to the slow breathing training, an intelligent guiding breathing algorithm based on feedback regulation mechanism was proposed to train patients to breathe slowly. Ten volunteers with hypertension were recruited and then trained to breathe slowly, accumulating up to 100 times using this device. The results showed that breath rate of the volunteers decreased from 15.16±0.92 times per minute to 9.40±0.29 times per minute, and meanwhile, time length of breath rate less than 8 times per minute in the proportion of total treatment time increased from 0.079±0.017 to 0.392±0.019 as the training times increased. In a conclusion, the proposed blood pressure depressor worked effectively in guiding slow breathing training.

[Design and implementation of real-time continuous glucose monitoring instrument].

Real-time continuous glucose monitoring can help diabetics to control blood sugar levels within the normal range. However, in the process of practical monitoring, the output of real-time continuous glucose monitoring system is susceptible to glucose sensor and environment noise, which will influence the measurement accuracy of the system. Aiming at this problem, a dual-calibration algorithm for the moving-window double-layer filtering algorithm combined with real-time self-compensation calibration algorithm is proposed in this paper, which can realize the signal drift compensation for current data. And a real-time continuous glucose monitoring instrument based on this study was designed. This real-time continuous glucose monitoring instrument consisted of an adjustable excitation voltage module, a current-voltage converter module, a microprocessor and a wireless transceiver module. For portability, the size of the device was only 40 mm × 30 mm × 5 mm and its weight was only 30 g. In addition, a communication command code algorithm was designed to ensure the security and integrity of data transmission in this study. Results of experiments in vitro showed that current detection of the device worked effectively. A 5-hour monitoring of blood glucose level in vivo showed that the device could continuously monitor blood glucose in real time. The relative error of monitoring results of the designed device ranged from 2.22% to 7.17% when comparing to a portable blood meter.

BML-111 Protected LPS/D-GalN-Induced Acute Liver Injury in Rats.

Lipoxins (LXs) display unique pro-resolving and anti-inflammatory functions in a variety of inflammatory conditions. The present study was undertaken to investigate the effects of BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester), the agonist of lipoxin A4 receptor, in a model of Lipopolysaccharides (LPS) and d-Galactosamine (d-GalN) induced acute liver injury, and to explore the mechanisms. Histopathological analyses were carried out to quantify liver injury degree. The activities of myeloperoxidase (MPO) were examined to evaluate the levels of neutrophil infiltration. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were detected to evaluate the functions of the liver. The amounts of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and interleukin-1ß (IL-1ß) were measured using enzyme-linked immunosorbent assay (ELISA), and the expression levels of transforming growth factor-ß1(TGF-ß1) and cyclooxygenase-2 (COX-2) were examined using Western blotting. The antioxidant capacity, the activities of inducible nitric oxide synthase (iNOS), the contents of malondialdehyde (MDA) and nitric oxide (NO) were analyzed with the kits via biochemical analysis. We established the model of acute liver injury with lipopolysaccharide and d-Galactosamine (LPS/d-GalN): (1) histopathological results and MPO activities, with the activities of AST and ALT in serum, consistently demonstrated LPS and d-GalN challenge could cause severe liver damage, but BML-111 could prevent pathological changes, inhibit neutrophil infiltration, and improve the hepatic function; (2) LPS/d-GalN increased TNF-α, IL-1ß, COX-2, and IL-10, while decreasing TGF-ß1. However, BML-111 could repress LPS/d-GalN -induced TNF-α, IL-1ß and COX-2, meanwhile increasing the expression levels of TGF-ß1 and IL-10; (3) LPS/d-GalN inhibited the activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and hydroxyl radical-scavenging ability, simultaneously increasing the levels of MDA and NO, so also the activity of iNOS. Otherwise, BML-111 could reverse all the phenomena. In a word, BML-111 played a protective role in acute liver injury induced by LPS and d-GalN in rats, through improving antioxidant capacity and regulating the balance of inflammatory cytokines.

Quantitative proteomic analysis reveals that antioxidation mechanisms contribute to cold tolerance in plantain (Musa paradisiaca L.; ABB Group) seedlings.

Banana and its close relative, plantain are globally important crops and there is considerable interest in optimizing their cultivation. Plantain has superior cold tolerance compared with banana and a thorough understanding of the molecular mechanisms and responses of plantain to cold stress has great potential value for developing cold tolerant banana cultivars. In this study, we used iTRAQ-based comparative proteomic analysis to investigate the temporal responses of plantain to cold stress. Plantain seedlings were exposed for 0, 6, and 24 h of cold stress at 8 °C and subsequently allowed to recover for 24 h at 28 °C. A total of 3477 plantain proteins were identified, of which 809 showed differential expression from the three treatments. The majority of differentially expressed proteins were predicted to be involved in oxidation-reduction, including oxylipin biosynthesis, whereas others were associated with photosynthesis, photorespiration, and several primary metabolic processes, such as carbohydrate metabolic process and fatty acid beta-oxidation. Western blot analysis and enzyme activity assays were performed on seven differentially expressed, cold-response candidate plantain proteins to validate the proteomics data. Similar analyses of the seven candidate proteins were performed in cold-sensitive banana to examine possible functional conservation, and to compare the results to equivalent responses between the two species. Consistent results were achieved by Western blot and enzyme activity assays, demonstrating that the quantitative proteomics data collected in this study are reliable. Our results suggest that an increase of antioxidant capacity through adapted ROS scavenging capability, reduced production of ROS, and decreased lipid peroxidation contribute to molecular mechanisms for the increased cold tolerance in plantain. To the best of our knowledge, this is the first report of a global investigation on molecular responses of plantain to cold stress by proteomic analysis.

[A wavelength selection approach of near infrared spectra Based on SCARS strategy and its application].

According to the characteristics of near infrared spectral(NIR)data, a new tactic called stability competitive adaptive reweighted sampling (SCARS) is employed to select characteristic wavelength variables of NIR data to build PLS model. This method is based on the stability of variables in PLS model. SCARS algorithm consists of a number of loops. In each loop, the stability of each corresponding variable is computed at first. Then enforced wavelength selection and adaptive reweighted sampling (ARS) is used to select important variables according to the stability of variables. The selected variables are kept as a variable subset and further used in the next loop. After the running of all loops, a number of subsets of variables are obtained and root mean squared error of cross validation (RMSECV) of PLS models is computed. The subset of variables with the lowest RMSECV is considered as the optimal variable subset. Validated by NIR data set of protein fodder solid-state fermentation process, the SCARS-PLS prediction model is better than PLS models based on wavelengths selected by competitive adaptive reweighted sampling (CARS) and Monte Carlo uninformative variable elimination (MC-UVE) methods. As a result, twenty one wavelength variables are selected by SCARS method to build the PLS prediction model with the predicted root mean square error (RMSEP) valued at 0.0543 and correlation coefficient (Rp) 0.9908. The results show that SCARS tactic can efficiently improve the accuracy and stability of NIR wavelength variables selection and optimize the precision of prediction model in solid-state fermentation process. The SCARS method has a certain application value.

Aquaporin 5 promotes the proliferation and migration of human gastric carcinoma cells.

Aquaporin 5 (AQP5) promotes the progression and invasion of several cancers, but its role in the tumorigenesis of human gastric carcinoma (GC) has not been clearly defined. Here, we investigated the potential functions of AQP5 in the proliferation and migration of human GC. RT-PCR and western blotting were used to detect the expression of AQP5 in human GC cell lines. Immunohistochemistry was applied to evaluate the expression of AQP5 in human GC tissues and corresponding normal tissues. Following ectopic overexpression of AQP5 or inhibition of AQP5 by its inhibitor, acetazolamide (AZA), cell proliferation and migration of AGS cells were analyzed by MTT assay, colony formation assay, and wound healing assay. Heterogeneous expression of AQP5 mRNA and protein was observed in human GC cell lines MKN45, MKN28, AGS, and SGC7901. AQP5 was up-regulated in GC tissues in comparison to corresponding normal tissues. AQP5 protein was mainly localized in the cell membrane. Overexpression of AQP5 was correlated with enhanced lymph node metastasis. In vitro, overexpression of AQP5 notably enhanced, while inhibition of AQP5 by AZA significantly attenuated the proliferation and migration of AGS cells. Our data indicate that AQP5 may play an important role in the tumorigenesis and progression of human GC and suggest that AQP5 is a potential therapeutic target against GC.

Association of rs1800795 and rs1800796 polymorphisms in interleukin-6 gene and osteoarthritis risk: evidence from a meta-analysis.

Multiple studies have investigated the association of interleukin-6 (IL-6) gene polymorphisms and osteoarthritis (OA) risk, but failed to reach a consistent conclusion. Therefore, this study was designed to elucidate the association of IL-6 polymorphisms and OA by a meta-analysis approach. Literature retrieval was carried out on PubMed, EMBASE, Web of Science, CNKI, and Wanfang databases. The strength of association was appraised by odds ratios (ORs) and 95% confidence intervals (95%CIs) in five genetic models. The data were merged by using RevMan 5.3 software. Ten studies with 4944 cases and 4651 controls were analyzed. Overall, no significant association was identified between rs1800795 polymorphism and OA. Subgroup analysis by ethnicity and OA site also suggested rs1800795 polymorphism was not associated with OA. For rs1800796 polymorphism, G-allele and GG-genotype carriers appeared to have an increased risk to OA (G vs. C, OR = 1.66, 95%CI 1.30-1.96, P < 0.01; GG vs. CC, OR = 1.75, 95%CI 1.07-2.84, P = 0.03; GG vs. GC + CC, OR = 1.82, 95%CI 1.42-2.34, P < 0.01). Findings of this study indicate that the rs1800795 polymorphism is not correlated to OA susceptibility, regardless of ethnicity or OA site. However, rs1800796 polymorphism trends to be associated with susceptibility to OA.

Role of purinergic signalling in obesity-associated end-organ damage: focus on the effects of natural plant extracts.

Obesity has become one of the major public health problems in both the developing and developed countries. Recent studies have suggested that the purinergic signalling is involved in obesity-associated end-organ damage through purine P1 and P2 receptors. In the search for new components for the treatments of obesity, we and other researchers have found much evidence that natural plant extracts may be promising novel therapeutic approaches by modulating purinergic signalling. In this review, we summarize a critical role of purinergic signalling in modulating obesity-associated end-organ damage, such as overhigh appetite, myocardial ischemia, inflammation, atherosclerosis, non-alcoholic fatty liver disease (NAFLD), hepatic steatosis and renal inflammation. Moreover, we focus on the potential roles of several natural plant extracts, including quercetin, resveratrol/trans-resveratrol, caffeine, evodiamine and puerarin, in alleviating obesity-associated end-organ damage via purinergic signalling. We hope that the current knowledge of the potential roles of natural plant extracts in regulating purinergic signalling would provide new ideas for the treatment of obesity and obesity-associated end-organ damage.

Helicobacter pylori-induced NAT10 stabilizes MDM2 mRNA via RNA acetylation to facilitate gastric cancer progression.

BACKGROUND: N4-acetylcytidine (ac4C), a widespread modification in human mRNAs that is catalyzed by the N-acetyltransferase 10 (NAT10) enzyme, plays an important role in promoting mRNA stability and translation. However, the biological functions and regulatory mechanisms of NAT10-mediated ac4C were poorly defined. METHODS: ac4C mRNA modification status and NAT10 expression levels were analyzed in gastric cancer (GC) samples and compared with the corresponding normal tissues. The biological role of NAT10-mediated ac4C and its upstream and downstream regulatory mechanisms were determined in vitro and in vivo. The therapeutic potential of targeting NAT10 in GC was further explored. RESULTS: Here, we demonstrated that both ac4C mRNA modification and its acetyltransferase NAT10 were increased in GC, and increased NAT10 expression was associated with disease progression and poor patient prognosis. Functionally, we found that NAT10 promoted cellular G2/M phase progression, proliferation and tumorigenicity of GC in an ac4C-depedent manner. Mechanistic analyses demonstrated that NAT10 mediated ac4C acetylation of MDM2 transcript and subsequently stabilized MDM2 mRNA, leading to its upregulation and p53 downregulation and thereby facilitating gastric carcinogenesis. In addition, Helicobacter pylori (Hp) infection contributed to NAT10 induction, causing MDM2 overexpression and subsequent p53 degradation. Further investigations revealed that targeting NAT10 with Remodelin showed anti-cancer activity in GC and augmented the anti-tumor activity of MDM2 inhibitors in p53 wild-type GC. CONCLUSIONS: These results suggest the critical role of NAT10-mediated ac4C modification in GC oncogenesis and reveal a previously unrecognized signaling cascade involving the Hp-NAT10-MDM2-p53 axis during GC development.

Metformin suppresses proliferation and differentiation induced by BMP9 via AMPK signaling in human fetal lung fibroblast-1.

Adenosine monophosphosphate-activated protein kinase (AMPK) and its activator metformin were found to be involved in the regulation of fibroblast activation and pulmonary fibrosis. However, the regulatory mechanism has been undetermined. Recently, AMPK has been reported to exert its effect through inhibiting bone morphogenetic protein (BMP) pathway. In this study, human fetal lung fibroblast (HFL-1) cells were treated with metformin or specific AMPKα1 mutants, including constitutively activated mutant (AMPK-CA) and dominant negative mutant (AMPK-DN), combined with BMP9, and then the absorbance of these cells was measured by cell counting kit (CCK)-8 assay. The colony number of HFL-1 cells stimulated by metformin with or without BMP9 was examined by colony formation assay. The protein expressions of differentiated markers (α-smooth muscle actin, collagen I and collagen III) and the key molecules of BMP9 signaling, including activin receptor-like kinase (ALK) one and phosphorylated small mother against decapentaplegic (p-Smad)1/5, were also evaluated by western blot. Data revealed that BMP9 induced the proliferation and differentiation of HFL-1 cells which was suppressed by metformin or AMPK-CA. Meanwhile, the effect of metformin on BMP9-induced activation was counteracted by AMPK-DN. In addition, we found that the expressions of ALK1 and p-Smad1/5 induced by BMP9 were attenuated by metformin and AMPK-CA, whereas the inhibitory responses of metformin to the increased ALK1 and p-Smad1/5 were reduced by AMPK-DN. Accordingly, these results suggested that metformin mitigated BMP9-induced proliferation and differentiation of HFL-1 cells, which was achieved partly through the activation of AMPK and inhibition of ALK1/Smad1/5 signaling.

Efficacy of Dimethyl Trisulfide on the Suppression of Ring Rot Disease Caused by Botryosphaeria dothidea and Induction of Defense-Related Genes on Apple Fruits.

Apple ring rot caused by Botryosphaeria dothidea is prevalent in main apple-producing areas in China, bringing substantial economic losses to the growers. In the present study, we demonstrated the inhibitory effect of dimethyl trisulfide (DT), one of the main activity components identified in Chinese leek (Allium tuberosum) volatile, on the apple ring rot on postharvest fruits. In in vitro experiment, 250 µL/L DT completely suppressed the mycelia growth of B. dothidea. In in vivo experiment, 15.63 µL/L DT showed 97% inhibition against the apple ring rot on postharvest fruit. In addition, the soluble sugar content, vitamin C content, and the soluble sugar/titratable acidity ratio of the DT-treated fruit were significantly higher than those of the control fruit. On this basis, we further explored the preliminary underlying mechanism. Microscopic observation revealed that DT seriously disrupted the normal morphology of B. dothidea. qRT-PCR determination showed the defense-related genes in DT-treated fruit were higher than those in the control fruit by 4.13-296.50 times, which showed that DT inhibited apple ring rot on postharvest fruit by suppressing the growth of B. dothidea, and inducing the defense-related genes in apple fruit. The findings of this study provided an efficient, safe, and environment-friendly alternative to control the apple ring rot on apple fruit.

The heat shock protein 20 gene editing suppresses mycelial growth of Botryosphaeria dothidea and decreases its pathogenicity to postharvest apple fruits.

Apple ring rot caused by Botryosphaeria dothidea is an essential and prevalent disease in the apple orchard in China. Our previous study demonstrated that dimethyl trisulfide (DT) from Chinese leek (Allium tuberosum) significantly suppressed the mycelial growth of B. dothidea and inhibited the incidence of apple ring rot postharvest. However, the mechanism underlying the inhibitory role of DT against B. dothidea is not fully understood. Comparing the control and the DT-treated B. dothidea mycelial transcriptomes revealed that heat shock protein 20 (Hsp20) strongly responded to DT treatment. This study identified four Hsp20 genes throughout the B. dothidea genome (BdHsp20_1-4). Each BdHsp20 gene had a conserved ACD with a variable N-terminal region and a short C-terminal extension. The segmental duplication event has contributed to the expansion of the BdHsp20 gene family. Compared to the wild-type strain, the CRISPR/Cas9 gene-edited BdHsp20 mutant (ΔBdHsp20) decreased the mycelial growth by 55.95% and reduced the disease symptom in postharvest apple fruit by 96.34%. However, the BdHsp20 complemented strain (ΔBdHsp20_C) significantly restored the growth and pathogenicity, which suggested that the BdHsp20 gene was closely involved in the growth and pathogenicity of B. dothidea. This study would accelerate the exploration of the molecular mechanism of the inhibitory effect of DT against B. dothidea and also provide new insights for the management of apple ring rot disease.

Endophytic bacterium Pseudomonas protegens suppresses mycelial growth of Botryosphaeria dothidea and decreases its pathogenicity to postharvest fruits.

Apple (Malus domestica Borkh.), one of the most economically important fruits widely consumed worldwide, has been suffering from apple ring rot caused by Botryosphaeria dothidea, which dramatically affects its quality and yield. In the present study, we demonstrated that Pseudomonas protegens, isolated from Chinese leek (Allium tuberosum), significantly suppressed the mycelial growth and propagation of B. dothidea, respectively, further displayed a considerably inhibitory effect on the apple ring rot of postharvest fruits. In addition, P. protegens significantly improved the total soluble solid/titrable acidity (TSS/TA) ratio and soluble sugar/titrable acidity (SS/TA) ratio and drastically maintained the fruit firmness. Further analysis manifested that P. protegens substantially induced the defense-related genes such as MdGLU, MdPAL, MdPOD, MdCAL, and transcription factors related to the resistance to B. dothidea, including MdWRKY15, MdPUB29, MdMyb73, and MdERF11 in apple fruits. Meanwhile, P. protegens considerably restrained the expressions of the pathogenicity-related genes in B. dothidea, including the BdCYP450, BdADH, BdGHY, BdATS, Bdα/ß-HY, and BdSTR. By inference, P. protegens inhibited the apple ring rot on postharvest fruits by activating the defense system of apple fruit and repressing the pathogenic factor of B. dothidea. The study provided a theoretical basis and a potential alternative to manage the apple ring rot on postharvest fruits.