Nickel oxide nanoparticles: A new generation nanoparticles to combat bacteria Xanthomonas oryzae pv. oryzae and enhance rice plant growth.

Recently, nanotechnology is among the most promising technologies used in all areas of research. The production of metal nanoparticles using plant parts has received significant attention for its environmental friendliness and effectiveness. Therefore, we investigated the possible applications of biological synthesized nickel oxide nanoparticles (NiONPs). In this study, NiONPs were synthesized through biological method using an aqueous extract of saffron stigmas (Crocus sativus L). The structure, morphology, purity, and physicochemical properties of the obtained NPs were confirmed through Scanning/Transmission Electron Microscopy attached with Energy Dispersive Spectrum, X-ray Diffraction, and Fourier transform infrared. The spherically shaped NiONPs were found by Debye Scherer's formula to have a mean dimension of 41.19 nm. The application of NiONPs in vitro at 50, 100, and 200 µg/mL, respectively, produced a clear region of 2.0, 2.2, and 2.5 cm. Treatment of Xoo cell with NiONPs reduced the growth and biofilm formation, respectively, by 88.68% and 83.69% at 200 µg/mL. Adding 200 µg/mL NiONPs into Xoo cells produced a significant amount of ROS in comparison with the control. Bacterial apoptosis increased dramatically from 1.05% (control) to 99.80% (200 µg/mL NiONPs). When compared to the control, rice plants treated with 200 µg/mL NiONPs significantly improved growth characteristics and biomass. Interestingly, the proportion of diseased leaf area in infected plants with Xoo treated with NiONPs reduced to 22% from 74% in diseased plants. Taken together, NiONPs demonstrates its effectiveness as a promising tool as a nano-bactericide in managing bacterial infection caused by Xoo.

Bio-formulated chitosan nanoparticles enhance disease resistance against rice blast by physiomorphic, transcriptional, and microbiome modulation of rice (Oryza sativa L.).

Rice blast disease (RBD) caused by Magnaporthe oryzae, threaten food security by cutting agricultural output. Nano agrochemicals are now perceived as sustainable, cost-effective alternatives to traditional pesticides. This study investigated bioformulation of moringa chitosan nanoparticles (M-CsNPs) and their mechanisms for suppressing RBD while minimizing toxic effects on the microenvironment. M-CsNPs, sized 46 nm with semi-spherical morphology, significantly suppressed pathogen growth, integrity, and colonization at 200 mg L-1in vitro. Greenhouse tests with foliar exposure to the same concentration resulted in a substantial 77.7 % reduction in RBD, enhancing antioxidant enzyme activity and plant health. Furthermore, M-CsNPs improved photosynthesis, gas exchange, and the nutritional profile of diseased rice plants. RNA-seq analysis highlighted upregulated defense-related genes in treated rice plants. Metagenomic study showcased reshaping of the rice microbiome, reducing Magnaporthe abundance by 93.5 %. Both healthy and diseased rice plants showed increased microbial diversity, particularly favoring specific beneficial species Thiobacillus, Nitrospira, Nocardioides, and Sphingomicrobium in the rhizosphere and Azonexus, Agarivorans, and Bradyrhizobium in the phyllosphere. This comprehensive study unravels the diverse mechanisms by which M-CsNPs interact with plants and pathogens, curbing M. oryzae damage, promoting plant growth, and modulating the rice microbiome. It underscores the significant potential for effective plant disease management.

MiR-145-5p overexpression rejuvenates aged adipose stem cells and accelerates wound healing.

Adipose-derived stem cells (ADSCs) have been widely applied in translational and regenerative medicine. During aging, there is a recognized functional decline in ADSCs, which compromises their therapeutic effectiveness. Currently, the mechanisms of aging-induced stem cell dysfunction remain unclear, hence there is a need to elucidate these mechanisms and propose strategies for reversing this functional impairment. In this study, we found that ADSCs isolated from old donors (O-ADSCs) presented inferior phenotypes and decreased miR-145-5p levels compared to those from young donors (Y-ADSCs). To interrogate the role of miR-145-5p in ADSCs, gain- and loss-of-function assays were performed. The results indicated that miR-145-5p overexpression in O-ADSCs promoted cellular proliferation and migration, while reducing cell senescence. Further study demonstrated that miR-145-5p could regulate ADSCs function by targeting bone morphogenetic protein binding endothelial cell precursor-derived regulator (BMPER), which is a crucial modulator in angiogenesis. Moreover, in vivo experiments showed that miR-145-5p-overexpressing O-ADSCs accelerated wound healing by promoting wound re-epithelialization and angiogenesis. Collectively, this study indicates that miR-145-5p works as a positive regulator for optimizing O-ADSCs function, and may be a novel therapeutic target for restoring aging-associated impairments in stem cell function.

Biomimetic hybrid nanovesicles improve infected diabetic wound via enhanced targeted delivery.

Infected diabetic wounds have been raising the global medical burden because of its high occurrence and resulting risk of amputation. Impaired endothelium has been well-documented as one of the most critical reasons for unhealed wounds. Recently, endothelial cell-derived nanovesicles (NVs) were reported to facilitate angiogenesis, whereas their efficacy is limited in infected diabetic wounds because of the complex niche. In this study, extrusion-derived endothelial NVs were manufactured and then hybridized with rhamnolipid liposomes to obtain biomimetic hybrid nanovesicles (HNVs). The HNVs were biocompatible and achieved endothelium-targeted delivery through membrane CXCR4-mediated homologous homing. More importantly, the HNVs exhibited better penetration and antibacterial activity compared with NVs, which further promote the intrinsic endothelium targeting in infected diabetic wounds. Therefore, the present research has established a novel bioactive delivery system-HNV with enhanced targeting, penetration, and antibacterial activity-which might be an encouraging strategy for infected diabetic wound treatment.

Copper oxide nanoparticles: an effective suppression tool against bacterial leaf blight of rice and its impacts on plants.

BACKGROUND: To address the challenges of food security for the ever-increasing population, the emergence of nanotechnology provides an alternate technology of choice for the production of safer pesticides which serves as a substitute for conventional fertilizer. The antidrug resistance of Xanthomonas oryzae pv. oryzae (Xoo) and build-up of chemicals in the environment has made it necessary to find alternative safe techniques for effective disease management. Hence, in this study, copper oxide nanoparticles (CuONPs) were produced by green synthesis using a Hibiscus rosa-sinensis L. flower extract. RESULTS: The characterization of CuONPs using ultraviolet-visible spectrophotometry, scanning electron microscopy with an energy-dispersive spectrum profile, Fourier transform infrared spectroscopy, and X-ray diffraction ascertained the presence of CuONPs, which were nanorods of 28.1 nm. CuONPs significantly obstructed the growth and biofilm development of Xoo by 79.65% and 79.17% respectively. The antibacterial mechanism of CuONPs was found to result from wounding the cell membrane, giving rise to an exodus of intracellular content and generation of oxidative reactive oxygen species that invariably inhibited Xoo respiration and growth. A toxicity study under greenhouse conditions revealed that CuONPs significantly increased growth variables and the biomass of rice, and reduced bacterial leaf blight. Application of CuONPs on Arabidopsis improved the chlorophyll fluorescence parameters; the ΦPSII was significantly increased by 152.05% in comparison to the control. CONCLUSION: Altogether, these results suggest that CuONPs in low concentration (200.0 µg mL-1 ) are not toxic to plants and can serve as nano-fertilizers and nano-pesticides. © 2023 Society of Chemical Industry.

Elevating plant immunity by translational regulation of a rice WRKY transcription factor.

Plants have intricate mechanisms that tailor their defence responses to pathogens. WRKY transcription factors play a pivotal role in plant immunity by regulating various defence signalling pathways. Many WRKY genes are transcriptionally activated upon pathogen attack, but how their functions are regulated after transcription remains elusive. Here, we show that OsWRKY7 functions as a crucial positive regulator of rice basal immunity against Xanthomonas oryzae pv. oryzae (Xoo). The activity of OsWRKY7 was regulated at both translational and post-translational levels. Two translational products of OsWRKY7 were generated by alternative initiation. The full-length OsWRKY7 protein is normally degraded by the ubiquitin-proteasome system but was accumulated following elicitor or pathogen treatment, whereas the alternate product initiated from the downstream in-frame start codon was stable. Both the full and alternate OsWRKY7 proteins have transcriptional activities in yeast and rice cells, and overexpression of each form enhanced resistance to Xoo infection. Furthermore, disruption of the main AUG in rice increased the endogenous translation of the alternate stabilized form of OsWRKY7 and enhanced bacterial blight resistance. This study provides insights into the coordination of alternative translation and protein stability in the regulation of plant growth and basal defence mediated by the OsWRKY7 transcription factor, and also suggests a promising strategy to breed disease-resistant rice by translation initiation control.

White adipose tissue-derived small extracellular vesicles: A new potential therapeutic reagent for accelerating diabetic wound healing.

Small extracellular vesicles (sEVs) from adipose-derived stem cells (ADSCs) have gained great attention and have been widely used in cell-free therapies for treating diabetic non-healing wounds in recent years. However, further clinical application of ADSC-sEVs have been limited due to their unsolvable defects, including cumbersome extraction procedure, high cost, low yield, etc. Thus, we urgently need to find one therapeutic reagent that could not only accelerate diabetic wound healing as ADSC-sEVs but also overcome these shortcomings. As the extraction process of adipose tissue-derived sEVs (AT-sEVs) is quite simple and labor saving, we put our focus on the efficiencies of white adipose tissue-derived sEVs (WAT-sEVs) and brown adipose tissue-derived sEVs (BAT-sEVs) in diabetic wound repair. After successfully isolating WAT-sEVs and BAT-sEVs by ultracentrifugation, we thoroughly characterized them and compared their diabetic wound healing capabilities both in vitro and in vivo. According to our study, AT-sEVs possess similar competence in diabetic wound healing as compared with ADSC-sEVs. While the effect of BAT-sEVs is not as stable as WAT-sEVs and ADSC-sEVs, the repair efficiency is also slightly lower than the other two sEVs in some cases. In summary, we are the first to discover that WAT-sEVs show great potential in diabetic wound repair. With advantages that are specific to tissue-derived sEVs (Ti-sEVs) such as time- and cost-saving, high-yield, and simple isolation procedure, we believe WAT-sEVs could serve as a novel reliable cell-free therapy for clinical diabetic wound treatment.

First Report of Leaf Spot Caused by Botrytis cinerea on Strawberry in China.

In the winter of 2022, circular or irregular leaf spots were observed on strawberry (Fragaria × ananassa) planted in commercial fields (cultivar 'xuetu', 'mengzhifu') in Yinzhou, Ningbo, Zhejiang, China (N29°48'48″, E121°39'47″), with disease incidence ranging from 10 to 15% in a field approximately 0.67 ha in size. The estimated crop loss associated with this disease was ~10%. Symptoms included circular or irregular lesions with brown halos and wheel marks, which eventually developed into leaf blight and petiole decay, but spore masses were seldom found on the leaf surface. In severe cases, leaves withered and abscissed. To isolate the causal agent, ten diseased leaves from ten different plants were collected, surface-sterilized with 75% ethanol for 50 s, rinsed twice with sterile distilled water, cut into small pieces (0.5 cm × 0.5 cm), and plated on potato dextrose agar (PDA), then incubated at 25°C in darkness for 5 days. Isolates , which displayed one kind of colony morphology were consistently obtained from each of the ten samples, and 58 single-conidium isolates with the same colony morphology were obtained. The isolation frequency was 58 of 60 samples. The colonies that grew on PDA produced white mycelia, which sporulated after 1 week, producing typical Botrytis-like gray spores. Three isolates (NBCM-1, NBCM-2, NBCM-3) were selected for identification and pathogenicity assays. Conidia were round to ellipsoid, 9.2 to 14.3 µm long (n=50), and 6.4 to 9.2 µm wide (n=50). Sclerotia were not observed on PDA. Based on these characteristics, the pathogen was tentatively identified as Botrytis cinerea (Zhang 2001). PCR was conducted for each of the three isolates to amplify the G3PDH, HSP60, RPB2, NEP1, and NEP2 genes, which are typically used for molecular identification of Botrytis species (Staats et al. 2005; Liu et al. 2016). The resulting amplicons were sequenced, and the sequences were processed using BLAST in the National Center for Biotechnology Information. Sequences of the three isolates were deposited in GenBank (accession nos. OR052082 to OR052086, OR493405 to OR493414). BLASTn analyses showed that isolates were 99 to 100% identical to B.cinerea reported causing leaf spot on strawberry in California; accession numbers MK919496 (G3PDH, 883/883 bp), MK919494 (HSP60, 992/992 bp), and MK919495 (RPB2, 1081/1081 bp). The resulting concatenated data set of G3PDH-HSP60-RPB2-NEP1-NEP2 was used to conduct a multilocus phylogenetic analysis (MLSA) using the maximum likelihood method. The MLSA tree indicated that the three isolates belonged to Botrytis cinerea. To test for pathogenicity, three 1-month-old strawberry (cultivar 'xuetu') plants were inoculated with each isolate (NBCM-1, NBCM-2, NBCM-3). A noninoculated control (sterile water only) was also included. The strawberry plants were inoculated by spraying with conidia suspension (1.0 × 105/ml) until run-off. Inoculations with sterile water served as controls. All plants were kept at 28/25°C (day/night), under a 12:12-h light/dark photoperiod. All plants were covered with transparent plastic bags to maintain humidity for the first 48 h, after which the bags were removed. After 4 to 7 days, leaf spot symptoms similar to those observed in the field were observed in all inoculated plants, while the controls remained healthy. The experiment was repeated three times. The pathogen was reisolated from the inoculated leaves and again identified as B. cinerea, with the same methodology used for the initial identification. Leaf spot caused by B. cinerea on strawberry was recently reported in California (Mansouripour and Holmes 2020) and Florida (Marin and Peres 2022). To our knowledge, this is the first report of B. cinerea causing leaf spot on strawberry in China. The pathogen is also the causal agent of Botrytis fruit rot on strawberry. Given the high variability of this pathogen (Marin and Peres 2022), further studies on its occurrence, spread, management, and control are required. The identification of this pathogen provides a basis for further research on its management and control.

Bio-functionalized nickel-silica nanoparticles suppress bacterial leaf blight disease in rice (Oryza sativa L.).

Introduction: Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most devastative diseases that threatens rice plants worldwide. Biosynthesized nanoparticle (NP) composite compounds have attracted attention as environmentally safe materials that possess antibacterial activity that could be used in managing plant diseases. Methods: During this study, a nanocomposite of two important elements, nickel and silicon, was biosynthesized using extraction of saffron stigmas (Crocus sativus L.). Characterization of obtained nickel-silicon dioxide (Ni-SiO2) nanocomposite was investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission/Scanning electron microscopy (TEM/SEM), and energy-dispersive spectrum (EDS). Antibacterial activities of the biosynthesized Ni-SiO2 nanocomposite against Xoo were tested by measuring bacterial growth, biofilm formation, and dead Xoo cells. Results and discussions: The bacterial growth (OD600) and biofilm formation (OD570) of Xoo treated with distilled water (control) was found to be 1.21 and 1.11, respectively. Treatment with Ni-SiO2 NPs composite, respectively, reduced the growth and biofilm formation by 89.07% and 80.40% at 200 µg/ml. The impact of obtained Ni-SiO2 nanocomposite at a concentration of 200 µg/ml was assayed on infected rice plants. Treatment of rice seedlings with Ni-SiO2 NPs composite only had a plant height of 64.8 cm while seedlings treated with distilled water reached a height of 45.20 cm. Notably, Xoo-infected seedlings treated with Ni-SiO2 NPs composite had a plant height of 57.10 cm. Furthermore, Ni-SiO2 NPs composite sprayed on inoculated seedlings had a decrease in disease leaf area from 43.83% in non-treated infected seedlings to 13.06% in treated seedlings. The FTIR spectra of biosynthesized Ni-SiO2 nanocomposite using saffron stigma extract showed different bands at 3,406, 1,643, 1,103, 600, and 470 cm-1. No impurities were found in the synthesized composite. Spherically shaped NPs were observed by using TEM and SEM. EDS revealed that Ni-SiO2 nanoparticles (NPs) have 13.26% Ni, 29.62% Si, and 57.11% O. Xoo treated with 200 µg/ml of Ni-SiO2 NPs composite drastically increased the apoptosis of bacterial cells to 99.61% in comparison with 2.23% recorded for the control. Conclusions: The application of Ni-SiO2 NPs significantly improved the vitality of rice plants and reduced the severity of BLB.

Bacteriophage-mediated biosynthesis of MnO2NPs and MgONPs and their role in the protection of plants from bacterial pathogens.

Introduction: Xanthomonas oryzae pv. oryzae (Xoo) is the plant pathogen of Bacterial Leaf Blight (BLB), which causes yield loss in rice. Methods: In this study, the lysate of Xoo bacteriophage X3 was used to mediate the bio-synthesis of MgO and MnO2. The physiochemical features of MgONPs and MnO2NPs were observed via Ultraviolet - Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Transmission/Scanning electron microscopy (TEM/SEM), Energy dispersive spectrum (EDS), and Fourier-transform infrared spectrum (FTIR). The impact of nanoparticles on plant growth and bacterial leaf blight disease were evaluated. Chlorophyll fluorescence was used to determine whether the nanoparticles application were toxic to the plants. Results: An absorption peak of 215 and 230 nm for MgO and MnO2, respectively, confirmed nanoparticle formation via UV-Vis. The crystalline nature of the nanoparticles was detected by the analysis of XRD. Bacteriological tests indicated that MgONPs and MnO2NPs sized 12.5 and 9.8 nm, respectively, had strong in vitro antibacterial effects on rice bacterial blight pathogen, Xoo. MnO2NPs were found to have the most significant antagonist effect on nutrient agar plates, while MgONPs had the most significant impact on bacterial growth in nutrient broth and on cellular efflux. Furthermore, no toxicity to plants was observed for MgONPs and MnO2NPs, indeed, MgONPs at 200 µg/mL significantly increased the quantum efficiency of PSII photochemistry on the model plant, Arabidopsis, in light (ΦPSII) compared to other interactions. Additionally, significant suppression of BLB was noted in rice seedlings amended with the synthesized MgONPs and MnO2NPs. MnO2NPs showed promotion of plant growth in the presence of Xoo compared to MgONPs. Conclusion: An effective alternative for the biological production of MgONPs and MnO2NPs was reported, which serves as an effective substitute to control plant bacterial disease with no phytotoxic effect.

Exosomal miR-125b-5p derived from adipose-derived mesenchymal stem cells enhance diabetic hindlimb ischemia repair via targeting alkaline ceramidase 2.

INTRODUCTION: Ischemic diseases caused by diabetes continue to pose a major health challenge and effective treatments are in high demand. Mesenchymal stem cells (MSCs) derived exosomes have aroused broad attention as a cell-free treatment for ischemic diseases. However, the efficacy of exosomes from adipose-derived mesenchymal stem cells (ADSC-Exos) in treating diabetic lower limb ischemic injury remains unclear. METHODS: Exosomes were isolated from ADSCs culture supernatants by differential ultracentrifugation and their effect on C2C12 cells and HUVECs was assessed by EdU, Transwell, and in vitro tube formation assays separately. The recovery of limb function after ADSC-Exos treatment was evaluated by Laser-Doppler perfusion imaging, limb function score, and histological analysis. Subsequently, miRNA sequencing and rescue experiments were performed to figure out the responsible miRNA for the protective role of ADSC-Exos on diabetic hindlimb ischemic injury. Finally, the direct target of miRNA in C2C12 cells was confirmed by bioinformatic analysis and dual-luciferase report gene assay. RESULTS: ADSC-Exos have the potential to promote proliferation and migration of C2C12 cells and to promote HUVECs angiogenesis. In vivo experiments have shown that ADSC-Exos can protect ischemic skeletal muscle, promote the repair of muscle injury, and accelerate vascular regeneration. Combined with bioinformatics analysis, miR-125b-5p may be a key molecule in this process. Transfer of miR-125b-5p into C2C12 cells was able to promote cell proliferation and migration by suppressing ACER2 overexpression. CONCLUSION: The findings revealed that miR-125b-5p derived from ADSC-Exos may play a critical role in ischemic muscle reparation by targeting ACER2. In conclusion, our study may provide new insights into the potential of ADSC-Exos as a treatment option for diabetic lower limb ischemia.

Phage combination alleviates bacterial leaf blight of rice (Oryza sativa L.).

Rice bacterial leaf blight (BLB) is the most destructive bacterial diseases caused by Xanthomonas oryzae pv. oryzae (Xoo). Phages have been proposed as a green and efficient strategy to kill bacterial pathogens in crops, however, the mechanism of action of phages in the control of phyllosphere bacterial diseases remain unclear. Here, the glasshouse pot experiment results showed that phage combination could reduce the disease index by up to 64.3%. High-throughput sequencing technology was used to analyze the characteristics of phyllosphere microbiome changes and the results showed that phage combinations restored the impact of pathogen invasion on phyllosphere communities to a certain extent, and increased the diversity of bacterial communities. In addition, the phage combination reduced the relative abundance of epiphytic and endophytic Xoo by 58.9% and 33.9%, respectively. In particular, Sphingomonas and Stenotrophomonas were more abundant. According to structural equation modeling, phage combination directly and indirectly affected the disease index by affecting pathogen Xoo biomass and phage resistance. In summary, phage combination could better decrease the disease index. These findings provide new insights into phage biological control of phyllosphere bacterial diseases, theoretical data support, and new ideas for agricultural green prevention and control of phyllosphere diseases.

Cobalt oxide nanoparticles: An effective growth promoter of Arabidopsis plants and nano-pesticide against bacterial leaf blight pathogen in rice.

Recently, the application of cobalt oxide nanoparticles (Co3O4NPs) has gained popularity owing to its magnetic, catalytic, optical, antimicrobial, and biomedical properties. However, studies on its use as a crop protection agent and its effect on photosynthetic apparatus are yet to be reported. Here, Co3O4NPs were first green synthesized using Hibiscus rosa-sinensis flower extract and were characterized using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission/scanning electron microscopy methods. Formation of the Co3O4NPs was attested based on surface plasmon resonance at 210 nm. XRD assay showed that the samples were crystalline having a mean size of 34.9 nm. The Co3O4NPs at 200 µg/ml inhibited the growth (OD600 = 1.28) and biofilm formation (OD570 = 1.37) of Xanthomonas oryzae pv. oryzae (Xoo) respectively, by 72.87% and 79.65%. Rice plants inoculated with Xoo had disease leaf area percentage (DLA %) of 57.25% which was significantly reduced to 11.09% on infected plants treated with 200 µg/ml Co3O4NPs. Also, plants treated with 200 µg/ml Co3O4NPs only had significant increment in shoot length, root length, fresh weight, and dry weight in comparison to plants treated with double distilled water. The application of 200 µg/ml Co3O4NPs on the Arabidopsis plant significantly increased the photochemical efficacy of PSII (ΦPSII) and photochemical quenching (qP) respectively, by 149.10% and 125.00% compared to the control while the non-photochemical energy dissipation (ΦNPQ) was significantly lowered in comparison to control. In summary, it can be inferred that Co3O4NPs can be a useful agent in the management of bacterial phytopathogen diseases.

Metabarcoding reveals response of rice rhizosphere bacterial community to rice bacterial leaf blight.

Rice bacterial leaf blight (BLB) is a major disease affecting cultivated rice and caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). It is well established that rhizosphere microorganisms could help improve the adaptability of plants to biotic stresses. However, it is still unclear about the response mechanism of rice rhizosphere microbial community to BLB infection. Here, we used 16S rRNA gene amplicon sequencing to explore the effect of BLB on the rice rhizosphere microbial community. The results show that the alpha diversity index of the rice rhizosphere microbial community decreased significantly at the onset of BLB and then gradually recovered to normal levels. Beta diversity analysis indicated that BLB significantly affected community composition. In addition, there were significant differences in the taxonomic composition between healthy and diseased groups. For example, ceretain genera were more abundant in diseased rhizospheres, namely Streptomyces, Sphingomonas, and Flavobacterium, among others. In addition, the size and complexity of the rhizosphere co-occurrence network increased after disease onset compared to healthy groups. Also, hub microbe Rhizobiaceae and Gemmatimonadaceae were identified in the diseased rhizosphere co-occurrence network, and these hub microbes played an important role in maintaining network stability. In conclusion, our results provide important insights into the rhizosphere microbial community response to BLB and also provide important data and ideas in using rhizosphere microbes to control BLB.

Tissue-derived extracellular vesicles: Isolation, purification, and multiple roles in normal and tumor tissues.

Extracellular vesicles (EVs) are particles released from cells, and their lipid bilayer membrane encloses large amounts of bioactive molecules that endow EVs with intercellular or inter-tissue communicational abilities. Tissue-derived extracellular vesicles (Ti-EVs) are EVs directly separated from the interstitial space of tissue. They could better reflect the actual physiological or pathological state of the tissue microenvironment compared with cell line-derived EVs and biofluid EVs, indicating their potential roles in elucidating the underlying mechanism of pathogenesis and guiding the diagnosis, therapeutic targeting, and cell-free treatment of diseases. However, there have been a relatively limited number of investigations of Ti-EVs. In this review, we have summarized general procedures for Ti-EVs isolation, as well as some caveats with respect to operations after the isolation step, such as purification and storage. In addition, we have also briefly concluded the current research trends on EVs from various normal and tumor tissues, aiming to cast new light on the future research direction of Ti-EVs.

Milk-derived exosomes carrying siRNA-KEAP1 promote diabetic wound healing by improving oxidative stress.

Diabetic wounds are a serious complication of diabetes mellitus (DM) that can lead to persistent infection, amputation, and even death. Prolonged oxidative stress has been widely recognized as a major instigator in the development of diabetic wounds; therefore, oxidative stress is considered a promising therapeutic target. In the present study, Keap1/Nrf2 signaling was confirmed to be activated in streptozotocin (STZ)-induced diabetic mice and methylglyoxal (MGO)-treated human umbilical vein endothelial cells (HUVECs). Knockdown of Keap1 by siRNA reversed the increase in Keap1 levels, promoted the nuclear translocation of Nrf2, and increased the expression of HO-1, an antioxidant protein. To explore therapeutic delivery strategies, milk-derived exosomes (mEXOs) were developed as a novel, efficient, and non-toxic siRNA carrier. SiRNA-Keap1 (siKeap1) was loaded into mEXOs by sonication, and the obtained mEXOs-siKeap1 were found to promote HUVEC proliferation and migration while relieving oxidative stress in MGO-treated HUVECs. Meanwhile, in a mouse model of diabetic wounds, injection of mEXOs-siKeap1 significantly accelerated diabetic wound healing with enhanced collagen formation and neovascularization. Taken together, these data support the development of Keap1 knockdown as a potential therapeutic strategy for diabetic wounds and demonstrated the feasibility of mEXOs as a scalable, biocompatible, and cost-effective siRNA delivery system. The therapeutic effect of siKeap1-loaded mEXOs on diabetic wound healing was assessed. First, we found that the expression of Keap1 was upregulated in the wounds of diabetic mice and in human umbilical vein endothelial cells (HUVECs) pretreated with methylglyoxal (MGO). Next, we extracted exosomes from raw milk by differential centrifugation and loaded siKeap1 into milk-derived exosomes by sonication. The in vitro application of the synthetic complex (mEXOs-siKeap1) was found to increase the nuclear localization of Nrf2 and the expression of the antioxidant protein HO-1, thus reversing oxidative stress. Furthermore, in vivo mEXOs-siKeap1 administration significantly accelerated the healing rate of diabetic wounds (Scheme 1). Scheme 1 Schematic diagram. A Synthesis of mEXOs-siKeap1 complex. B Mechanism of mEXOs-siKeap1 in vitro. C The treatment effect of mEXOs-siKeap1 on an in vivo mouse model of diabetic wounds.

Bioinspired Green Synthesis of Silver Nanoparticles Using Three Plant Extracts and Their Antibacterial Activity against Rice Bacterial Leaf Blight Pathogen Xanthomonas oryzae pv. oryzae.

Rice bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is responsible for a significant reduction in rice production. Due to the small impact on the environment, biogenic nanomaterials are regarded as a new type of antibacterial agent. In this research, three colloids of silver nanoparticles (AgNPs) were synthesized with different biological materials such as Arctium lappa fruit, Solanum melongena leaves, and Taraxacum mongolicum leaves, and called Al-AgNPs, Sm-AgNPs and Tm-AgNPs, respectively. The appearance of brown colloids and the UV-Visible spectroscopy analysis proved the successful synthesis of the three colloids of AgNPs. Moreover, FTIR and XRD analysis revealed the formation of AgNPs structure. The SEM and TEM analysis indicated that the average diameters of the three synthesized spherical AgNPs were 20.18 nm, 21.00 nm, and 40.08 nm, respectively. The three botanical AgNPs had the strongest bacteriostatic against Xoo strain C2 at 20 µg/mL with the inhibition zone of 16.5 mm, 14.5 mm, and 12.4 mm, while bacterial numbers in a liquid broth (measured by OD600) decreased by 72.10%, 68.19%, and 65.60%, respectively. Results showed that the three AgNPs could inhibit biofilm formation and swarming motility of Xoo. The ultrastructural observation showed that Al-AgNPs adhered to the surface of bacteria and broke the bacteria. Overall, the three synthetic AgNPs could be used to inhibit the pathogen Xoo of rice bacterial leaf blight.

Elucidation of endothelial progenitor cell dysfunction in diabetes by RNA sequencing and constructing lncRNA-miRNA-mRNA competing endogenous RNA network.

With the rapid increase in the incidence of diabetes, non-healing diabetic wounds have posed a huge challenge to public health. Endothelial progenitor cell (EPC) has been widely reported to promote wound repairing, while its number and function were suppressed in diabetes. However, the specific mechanisms and competing endogenous RNA (ceRNA) network of EPCs in diabetes remain largely unknown. Thus, the transcriptome analyses were carried in the present study to clarify the mechanism underlying EPCs dysfunction in diabetes. EPCs were successfully isolated from rats. Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. The differentially expressed (DE) RNAs were successfully identified by RNA sequencing in the control and diabetic groups. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that DE mRNAs were significantly enriched in terms and pathways involved in the functions of EPCs and wound healing. Protein-protein interaction networks revealed critical DE mRNAs in the above groups. Moreover, the whole lncRNA-miRNA-mRNA ceRNA network was constructed, in which 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by quantitative real-time polymerase chain reaction. Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes. The present research provided novel insight into the underlying mechanism of EPCs dysfunction in diabetes and prompted potential targets to restore the impaired functions, thus accelerating diabetic wound healing. KEY MESSAGES: • Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. • The DE RNAs were successfully identified by RNA sequencing in the control and diabetic groups and analyzed by DE, GO, and KEGG analysis. • PPI and lncRNA-miRNA-mRNA ceRNA networks were constructed. • 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by qRT-PCR. • Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes.

Phage Resistance Reduced the Pathogenicity of Xanthomonas oryzae pv. oryzae on Rice.

Plants grow together with microbes that have both negative and positive impacts on the host, while prokaryotes are in turn also hosts for viruses, co-evolving together in a complex interrelationship. Most research focuses on the interaction of either bacterial pathogens interacting with the plant host, or the impact on viruses on their pathogenic bacterial hosts. Few studies have investigated the co-evolution of bacterial pathogens with their host plants as well as with their bacterial viruses. In this work, we aimed to identify the genes that were associated with both phage sensitivity and host pathogenicity of the bacterium Xanthomonas oryzae pv. oryzae (Xoo), which is the most important bacterial rice pathogen. Using the Tn5 transposon mutation technology, we created a library of Xoo strain C2 comprising 4524 mutants, which were subsequently tested for phage infectability. The phage infection tests showed that less than 1% of the mutants (n = 36) were resistant to phage infection, which was attributed to the Tn5 insertion in 19 genes. Interestingly, three out of 19 genes that conveyed resistance to the phage resulted in reduced pathogenicity to rice seedlings compared to the wild type. We identified three genes involved in both phage infection and bacterial virulence, which were studied by knockout mutants and complementation experiments. All of the three knockout mutants were resistant to infection by phage X2, while the complemented strains restored the susceptibility to the bacterial virus. Surprisingly, the genes are also essential for pathogenicity, which we confirmed by single knockout mutants corresponding to the Tn5 mutants. All three genes are involved in lipopolysaccharide synthesis, thus changing the cell envelope surface molecule composition. Our work shows a possible balance in terms of the connection between bacterial virulence and phage resistance, supporting the deployment of phages for the biocontrol of plant pathogens.

Whole-Transcriptome Analysis Reveals Autophagy Is Involved in Early Senescence of zj-es Mutant Rice.

Senescence is a necessary stage of plant growth and development, and the early senescence of rice will lead to yield reduction and quality decline. However, the mechanisms of rice senescence remain obscure. In this study, we characterized an early-senescence rice mutant, designated zj-es (ZheJing-early senescence), which was derived from the japonica rice cultivar Zhejing22. The mutant zj-es exhibited obvious early-senescence phenotype, such as collapsed chloroplast, lesions in leaves, declined fertility, plant dwarf, and decreased agronomic traits. The ZJ-ES gene was mapped in a 458 kb-interval between the molecular markers RM5992 and RM5813 on Chromosome 3, and analysis suggested that ZJ-ES is a novel gene controlling rice early senescence. Subsequently, whole-transcriptome RNA sequencing was performed on zj-es and its wild-type rice to dissect the underlying molecular mechanism for early senescence. Totally, 10,085 differentially expressed mRNAs (DEmRNAs), 1,253 differentially expressed lncRNAs (DElncRNAs), and 614 differentially expressed miRNAs (DEmiRNAs) were identified, respectively, in different comparison groups. Based on the weighted gene co-expression network analysis (WGCNA), the co-expression turquoise module was found to be the key for the occurrence of rice early senescence. Furthermore, analysis on the competing endogenous RNA (CeRNA) network revealed that 14 lncRNAs possibly regulated 16 co-expressed mRNAs through 8 miRNAs, and enrichment analysis showed that most of the DEmRNAs and the targets of DElncRNAs and DEmiRNAs were involved in reactive oxygen species (ROS)-triggered autophagy-related pathways. Further analysis showed that, in zj-es, ROS-related enzyme activities were markedly changed, ROS were largely accumulated, autophagosomes were obviously observed, cell death was significantly detected, and lesions were notably appeared in leaves. Totally, combining our results here and the remaining research, we infer that ROS-triggered autophagy induces the programmed cell death (PCD) and its coupled early senescence in zj-es mutant rice.