Enhanced C-To-T and A-To-G Base Editing in Mitochondrial DNA with Engineered DdCBE and TALED

Mitochondrial base editing with DddA-derived cytosine base editor (DdCBE) is limited in the accessible target sequences and modest activity. Here, the optimized DdCBE tools is presented with improved editing activity and expanded C-to-T targeting scope by fusing DddA11 variant with different cytosine deaminases with single-strand DNA activity. Compared to previous DdCBE based on DddA11 variant alone, fusion of the activation-induced cytidine deaminase (AID) from Xenopus laevis not only permits cytosine editing of 5'-GC-3' sequence, but also elevates editing efficiency at 5'-TC-3', 5'-CC-3', and 5'-GC-3' targets by up to 25-, 10-, and 6-fold, respectively. Furthermore, the A-to-G editing efficiency is significantly improved by fusing the evolved DddA6 variant with TALE-linked deoxyadenosine deaminase (TALED). Notably, the authors introduce the reported high-fidelity mutations in DddA and add nuclear export signal (NES) sequences in DdCBE and TALED to reduce off-target editing in the nuclear and mitochondrial genome while improving on-target editing efficiency in mitochondrial DNA (mtDNA). Finally, these engineered mitochondrial base editors are shown to be efficient in installing mtDNA mutations in human cells or mouse embryos for disease modeling. Collectively, the study shows broad implications for the basic study and therapeutic applications of optimized DdCBE and TALED.

An Ustilaginoidea virens glycoside hydrolase 42 protein is an essential virulence factor and elicits plant immunity as a PAMP

Rice false smut, caused by the ascomycete fungus Ustilaginoidea virens, which infects rice florets before heading, severely threatens rice grain yield and quality worldwide. The U. virens genome encodes a number of glycoside hydrolase (GH) proteins. So far, the functions of these GHs in U. virens are largely unknown. In this study, we identified a GH42 protein secreted by U. virens, named UvGHF1, that exhibits β-galactosidase activity. UvGHF1 not only functions as an essential virulence factor during U. virens infection, but also serves as a pathogen-associated molecular pattern (PAMP) in Nicotiana benthamiana and rice. The PAMP activity of UvGHF1 is independent of its β-galactosidase activity. Moreover, UvGHF1 triggers cell death in N. benthamiana in a BAK1-dependent manner. Ectopic expression of UvGHF1 in rice induces pattern-triggered immunity and enhances rice resistance to fungal and bacterial diseases. RNA-seq analysis revealed that UvGHF1 expression in rice not only activates expression of many defence-related genes encoding leucine-rich repeat receptor-like kinases and WRKY and ERF transcription factors, but also induces diterpenoid biosynthesis and phenylpropanoid biosynthesis pathways. Therefore, UvGHF1 contributes to U. virens virulence, but is also recognized by the rice surveillance system to trigger plant immunity.

Transcriptome analysis reveals the mechanism for blue-light-induced biosynthesis of delphinidin derivatives in harvested purple pepper fruit

Anthocyanins are the main pigments that affect the color and quality of purple-fruited sweet pepper (Capsicum annuum). Our previous study indicated that blue light can induce anthocyanin accumulation in purple pepper. In view of its underlying mechanism that is unclear, here, anthocyanin content was determined, and transcriptome analysis was performed on pepper fruits harvested from different light treatments. As a result, among the identified anthocyanin metabolites, the levels of delphinidin (Dp) glycosides, including Dp-3-O-rhamnoside, Dp-3-O-rutinoside, and Dp-3-O-glucoside, were highly accumulated in blue-light-treated fruit, which are mainly responsible for the appearance color of purple pepper. Correlation between anthocyanin content and transcriptomic analysis indicated a total of 1,619 upregulated genes were found, of which six structural and 12 transcription factor (TF) genes were involved in the anthocyanin biosynthetic pathway. Structural gene, for instance, CaUFGT as well as TFs such as CaMYC2-like and CaERF113, which were highly expressed under blue light and presented similar expression patterns consistent with Dp glycoside accumulation, may be candidate genes for anthocyanin synthesis in response to blue-light signal.

Row ratio increasing improved light distribution, photosynthetic characteristics, and yield of peanut in the maize and peanut strip intercropping system

Changes in the canopy microclimate in intercropping systems, particularly in the light environment, have important effects on the physiological characteristics of photosynthesis and yield of crops. Although different row ratio configurations and strip widths of dwarf crops in intercropping systems have important effects on canopy microclimate, little information is available on the effects of intercropping on chlorophyll synthesis and photosynthetic physiological properties of dwarf crops. A 2-year field experiment was conducted in 2019 and 2020, with five treatments: sole maize (SM), sole peanut (SP), four rows of maize intercropping with eight rows of peanut (M4P8), four rows of maize intercropping with four rows of peanut (M4P4), and four rows of maize intercropping with two rows of peanut (M4P2). The results showed that the light transmittance [photosynthetically active radiation (PAR)], photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) of intercropped peanut canopy were reduced, while the intercellular carbon dioxide concentration (Ci) was increased, compared with SP. In particular, the M4P8 pattern Pn (2-year mean) was reduced by 5.68%, 5.33%, and 5.30%; Tr was reduced by 7.41%, 5.45%, and 5.95%; and Gs was reduced by 8.20%, 6.88%, and 6.46%; and Ci increased by 11.95%, 8.06%, and 9.61% compared to SP, at the flowering needle stage, pod stage, and maturity, respectively. M4P8 improves the content of chlorophyll synthesis precursor and conversion efficiency, which promotes the utilization efficiency of light energy. However, it was significantly reduced in M4P2 and M4P4 treatment. The dry matter accumulation and pod yield of peanut in M4P8 treatment decreased, but the proportion of dry matter distribution in the late growth period was more transferred to pods. The full pod number decreases as the peanut row ratio decreases and increases with year, but there is no significant difference between years. M4P8 has the highest yield and land use efficiency and can be used as a reference row ratio configuration for maize-peanut intercropping to obtain relatively high yield benefits.

Genome-wide characterization of the PP2C gene family in peanut (Arachis hypogaea L.) and the identification of candidate genes involved in salinity-stress response

Plant protein phosphatase 2C (PP2C) play important roles in response to salt stress by influencing metabolic processes, hormone levels, growth factors, etc. Members of the PP2C family have been identified in many plant species. However, they are rarely reported in peanut. In this study, 178 PP2C genes were identified in peanut, which were unevenly distributed across the 20 chromosomes, with segmental duplication in 78 gene pairs. AhPP2Cs could be divided into 10 clades (A-J) by phylogenetic analysis. AhPP2Cs had experienced segmental duplications and strong purifying selection pressure. 22 miRNAs from 14 different families were identified, targeting 57 AhPP2C genes. Gene structures and motifs analysis exhibited PP2Cs in subclades AI and AII had high structural and functional similarities. Phosphorylation sites of AhPP2C45/59/134/150/35/121 were predicted in motifs 2 and 4, which located within the catalytic site at the C-terminus. We discovered multiple MYB binding factors and ABA response elements in the promoter regions of the six genes (AhPP2C45/59/134/150/35/121) by cis-elements analysis. GO and KEGG enrichment analysis confirmed AhPP2C-A genes in protein binding, signal transduction, protein modification process response to abiotic stimulus through environmental information processing. Based on RNA-Seq data of 22 peanut tissues, clade A AhPP2Cs showed a varying degree of tissue specificity, of which, AhPP2C35 and AhPP2C121 specifically expressed in seeds, while AhPP2C45/59/134/150 expressed in leaves and roots. qRT-PCR indicated that AhPP2C45 and AhPP2C134 displayed significantly up-regulated expression in response to salt stress. These results indicated that AhPP2C45 and AhPP2C134 could be candidate PP2Cs conferring salt tolerance. These results provide further insights into the peanut PP2C gene family and indicate PP2Cs potentially involved in the response to salt stress, which can now be further investigated in peanut breeding efforts to obtain cultivars with improved salt tolerance.

Comparative transcriptomics identifies the key in planta-expressed genes of Fusarium graminearum during infection of wheat varieties

Fusarium head blight (FHB), caused mainly by the fungus Fusarium graminearum, is one of the most devastating diseases in wheat, which reduces the yield and quality of grain. Fusarium graminearum infection of wheat cells triggers dynamic changes of gene expression in both F. graminearum and wheat, leading to molecular interactions between pathogen and host. The wheat plant in turn activates immune signaling or host defense pathways against FHB. However, the mechanisms by which F. graminearum infects wheat varieties with different levels of host resistance are largely limited. In this study, we conducted a comparative analysis of the F. graminearum transcriptome in planta during the infection of susceptible and resistant wheat varieties at three timepoints. A total of 6,106 F. graminearum genes including those functioning in cell wall degradation, synthesis of secondary metabolites, virulence, and pathogenicity were identified during the infection of different hosts, which were regulated by hosts with different genetic backgrounds. Genes enriched with metabolism of host cell wall components and defense response processes were specifically dynamic during the infection with different hosts. Our study also identified F. graminearum genes that were specifically suppressed by signals derived from the resistant plant host. These genes may represent direct targets of the plant defense against infection by this fungus. Briefly, we generated databases of in planta-expressed genes of F. graminearum during infection of two different FHB resistance level wheat varieties, highlighted their dynamic expression patterns and functions of virulence, invasion, defense response, metabolism, and effector signaling, providing valuable insight into the interactions between F. graminearum and susceptible/resistant wheat varieties.

Regulatory network characterization of anthocyanin metabolites in purple sweetpotato via joint transcriptomics and metabolomics

INTRODUCTION

Sweet potato is an important staple food crop in the world and contains abundant secondary metabolites in its underground tuberous roots. The large accumulation of several categories of secondary metabolites result in colorful pigmentation of the roots. Anthocyanin, is a typical flavonoid compound present in purple sweet potatoes and it contributes to the antioxidant activity.

METHODS

In this study, we developed joint omics research via by combing the transcriptomic and metabolomic analysis to explore the molecular mechanisms underlying the anthocyanin biosynthesis in purple sweet potato. Four experimental materials with different pigmentation phenotypes, 1143-1 (white root flesh), HS (orange root flesh), Dianziganshu No.88 (DZ88, purple root flesh), and Dianziganshu No.54 (DZ54, dark purple root flesh) were comparably studied.

RESULTS AND DISCUSSION

We identified 38 differentially accumulated pigment metabolites and 1214 differentially expressed genes from a total of 418 metabolites and 50893 genes detected. There were 14 kinds of anthocyanin detected in DZ88 and DZ54, with glycosylated cyanidin and peonidin as the major components. The significantly enhanced expression levels of multiple structural genes involved in the central anthocyanin metabolic network, such as chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase/leucocyanidin oxygenase (ANS), and glutathione S-transferase (GST) were manifested to be the primary reason why the purple sweet potatoes had a much higher accumulation of anthocyanin. Moreover, the competition or redistribution of the intermediate substrates (i.e. dihydrokaempferol and dihydroquercetin) between the downstream production of anthocyanin products and the flavonoid derivatization (i.e. quercetin and kaempferol) under the regulation of the flavonol synthesis (FLS) gene, might play a crucial role in the metabolite flux repartitioning, which further led to the discrepant pigmentary performances in the purple and non-purple materials. Furthermore, the substantial production of chlorogenic acid, another prominent high-value antioxidant, in DZ88 and DZ54 seemed to be an interrelated but independent pathway differentiated from the anthocyanin biosynthesis. Collectively, these data from the transcriptomic and metabolomic analysis of four kinds of sweet potatoes provide insight to understand the molecular mechanisms of the coloring mechanism in purple sweet potatoes.

Design of field real-time target spraying system based on improved YOLOv5

Deep learning techniques have made great progress in the field of target detection in recent years, making it possible to accurately identify plants in complex environments in agricultural fields. This project combines deep learning algorithms with spraying technology to design a machine vision precision real-time targeting spraying system for field scenarios. Firstly, the overall structure scheme of the system consisting of image acquisition and recognition module, electronically controlled spray module and pressure-stabilized pesticide supply module was proposed. After that, based on the target detection model YOLOv5s, the model is lightened and improved by replacing the backbone network and adding an attention mechanism. Based on this, a grille decision control algorithm for solenoid valve group on-off was designed, while common malignant weeds were selected as objects to produce data sets and complete model training. Finally, the deployment of the hardware system and detection model on the electric spray bar sprayer was completed, and field trials were conducted at different speeds. The experimental results show that the improved algorithm reduces the model size to 53.57% of the original model with less impact on mAP accuracy, improves FPS by 18.16%. The accuracy of on-target spraying at 2km/h, 3km/h and 4km/h speeds were 90.80%, 86.20% and 79.61%, respectively, and the spraying hit rate decreased as the operating speed increased. Among the hit rate components, the effective recognition rate was significantly affected by speed, while the relative recognition hit rate was less affected.

Effects of chicken manure substitution for mineral nitrogen fertilizer on crop yield and soil fertility in a reduced nitrogen input regime of North-Central China

Organic manure has been proposed to substitute part of the chemical fertilizers. However, past research was usually conducted in regimes with excessive nitrogen (N) fertilization, which was not conducive to the current national goal of green and sustainable development. Therefore, exploring the potential of organic fertilizer substitution for mineral N fertilizer under regimes with reduced N inputs is important to further utilize organic fertilizer resources and establish sustainable nutrient management recommendations in the winter wheat (Triticum aestivum L.) - summer maize (Zea mays L.) rotation system in North-central China. In this study, a 4-year field experiment was conducted to investigate the effects of different chicken manure substitution ratios on crop yield, N recovery efficiency (REN), soil N and soil organic matter contents, to clarify the optimal organic substitution ratio of N fertilizer under reduced N application (from 540 kg N ha^-1 year^-1 to 400 kg N ha^-1 year^-1). Six substitution ratios were assessed: 0%, 20%, 40%, 60%, 80% and 100% under 200 kg N ha^-1 per crop season, respectively, plus a control with no N application from chemical fertilizer or chicken manure. Results showed that the highest yield was achieved under the 20% substitution ratio treatment, with 1.1% and 2.3% higher yield than chemical N alone in wheat season and maize seasons, respectively. At the chicken manure substitution ratios of 20% in wheat season and 20%-40% in maize season, the highest REN reached to 31.2% and 26.1%, respectively. Chicken manure application reduced soil residual inorganic N with increasing substitution ratio. All organic substitution treatments increased soil organic matter and total N content. Implementing 20% organic substitution in wheat season and 20%-40% in maize season under the reduced N application regime in the North-central China is therefore recommended in order to achieve high crop yields and REN, improve soil fertility and enhance livestock manure resource utilization.

Identification of new resistance loci against wheat sharp eyespot through genome-wide association study

INTRODUCTION

Wheat sharp eyespot caused by Rhizoctonia cerealis is a serious pathogenic disease affecting plants. The effective strategy for controlling this disease is breeding resistant cultivar. However, to date, no wheat varieties are fully resistant to sharp eyespot, and only a few quantitative trait loci (QTLs) have been shown to be associated with sharp eyespot resistance.

METHODS

To understand the genetic basis of this disease, a genome-wide association study (GWAS) of sharp eyespot resistance in 262 varieties from all China wheat regions was conducted.

RESULTS

After cultivation for three years, only 6.5% of the varieties were resistant to sharp eyespot. Notably, the varieties from the middle and lower Yangtze River displayed higher sharp eyespot resistance than those from Huanghuai wheat zone. Only two varieties had the same resistance level to the control Shanhongmai. The results of GWAS showed that 5 single nucleotide polymorphism (SNP) loci were markedly related to sharp eyespot resistance in the three years repeatedly, and two QTLs, qSE-6A and qSE-7B, on chromosome 6A and 7B were identified. Based on the 'CG' haplotypes of significant SNPs, we found that the two QTLs exhibited additive effects on attenuating sharp eyespot resistance.

DISCUSSION

These results provide novel insights into the genetic basis of sharp eyespot resistance in China wheat varieties. The SNPs related to sharp eyespot resistance can be applied for marker-assisted selection in plant breeding.

Sown alfalfa pasture decreases grazing intensity while increasing soil carbon: Experimental observations and DNDC model predictions

INTRODUCTION

Grasslands are the most important land use in China and have experienced extensive degradation in the past few decades due to overgrazing. However, regionally viable solutions to grazing intensity alleviation remained elusive to date.

METHODS

Here, we evaluated the grazing intensity effects of sown alfalfa pastures in northern China using an experiment-modeling combined approach that involved six sites in field experiments and five provinces in DNDC modeling of sown alfalfa pasture's forage production and carbon sequestration potentials in marginal lands.

RESULTS

Our results showed that the sown alfalfa pasture's dry-matter yield varied between 4.5 and 9.0 Mg ha-1 under rainfed and irrigated conditions, respectively, from 2025 to 2035. If half of the available marginal lands were mobilized for alfalfa forage production, these yield levels meant that livestock grazing intensity on natural grasslands may drop 8-13% under rainfed and 20-33% under irrigated conditions. Our results also showed that marginal land's soil organic carbon contents were systematically higher under sown alfalfa pasture than under fallow management by a big margin of 8.5 and 9.9 g kg-1 (i.e., +79 and +95%), under rainfed and irrigated conditions, respectively, during 2025-2035.

DISCUSSION

Overall, these results demonstrated that sown alfalfa pasture on marginal lands represents an effective grassland conservation pathway over the short- to medium-term time horizon based on current technologies.

Low fish meal diet supplemented with probiotics ameliorates intestinal barrier and immunological function of Macrobrachium rosenbergii via the targeted modulation of gut microbes and derived secondary metabolites

The unsuitable substitution ratio of fish meal by plant protein will reshape the intestinal microbial composition and intestine immunity. However, previous studies were mostly limited to investigating how different feed or probiotics characterized the microbial composition but ignored the biological interactions between bacteria and host physiology through secondary metabolites. Therefore, this study integrates the apparent indicators monitoring, 16S rDNA sequencing, and metabonomics to systematically investigate the effects of cottonseed protein concentrate (CPC) substitution of fish meal and Bacillus coagulans intervention on gut microbes, secondary metabolites, and intestinal immunity of Macrobrachium rosenbergii. Prawns were fed with three diets for 70 days: HF diets contained 25% fish meal, CPC in LF diets were replaced with 10% fish meal, and LF diets supplemented with 2 × 108 CFU/g diet B. coagulans were designated as BC diets. Results showed that CPC substitution induced a significant decrease in digestive enzyme activities (trypsin and lipase) and gut barrier protein PT-1 expression and a significant increase in γ-GT enzyme activity and inflammatory-related factors (Relish and Toll) expression. B. coagulans treatment mitigated the negative changes of the above indicators. Meanwhile, it significantly improved the expression levels of the barrier factor PT-1, the reparative cytokine IL-22, and Cu/Zn-SOD. CPC substitution resulted in a remarkable downregulated abundance of Firmicutes phyla, Flavobacterium spp., and Bacillus spp. B. coagulans treatment induced the callback of Firmicutes abundance and improved the relative abundance of Sphingomonas, Bacillus, and Ralstonia. Functional prediction indicated that CPC substitution resulted in elevated potential pathogenicity of microbial flora, and B. coagulans reduces the pathogenesis risk. Pearson's correlation analysis established a significant positive correlation between differential genera (Sphingomonas, Bacillus, and Ralstonia) and secondary metabolites (including sphingosine, dehydrophytosphingosine, amino acid metabolites, etc.). Meanwhile, the latter were significantly associated with intestinal immunoregulation-related genes (Cu/Zn-SOD, IL-22, PT-1, Toll, and Relish). This study indicated that B. coagulans could mediate specific gut microbes and the combined action of multiple functional secondary metabolites to affect intestinal barrier function, digestion, and inflammation. Our study revealed the decisive role of gut microbes and derived secondary metabolites in the model of dietary composition-induced intestinal injury and probiotic treatment from a new perspective.

Changes in soil fungal communities after onset of wheat yellow mosaic virus disease

Rhizosphere-associated microbes have important implications for plant health, but knowledge of the association between the pathological conditions of soil-borne virus-infected wheat and soil microbial communities, especially changes in fungal communities, remains limited. We investigated the succession of fungal communities from bulk soil to wheat rhizosphere soil in both infected and healthy plants using amplicon sequencing methods, and assessed their potential role in plant health. The results showed that the diversity of fungi in wheat rhizosphere and bulk soils significantly differed post wheat yellow mosaic virus disease onset. The structure differences in fungal community at the two wheat health states or two compartment niches were evident, soil physicochemical properties (i.e., NH4 +) contribute to differences in fungal community structure and alpha diversity. Comparison analysis showed Mortierellomycetes and Dothideomycetes as dominant communities in healthy wheat soils at class level. The genus Pyronemataceae and Solicoccozyma were significantly are significantly enriched in rhizosphere soil of diseased plant, the genus Cystofilobasidium, Cladosporium, Mortierella, and Stephanonectria are significantly enriched in bulk soil of healthy plant. Co-occurrence network analysis showed that the fungi in healthy wheat soil has higher mutual benefit and connectivity compared with diseased wheat. The results of this study demonstrated that the occurrence of wheat yellow mosaic virus diseases altered both fungal community diversity and composition, and that NH4 + is the most important soil physicochemical factor influencing fungal diversity and community composition.

WGCNA analysis revealing molecular mechanism that bio-organic fertilizer improves pear fruit quality by increasing sucrose accumulation and reducing citric acid metabolism

It's been long known that the application of organic fertilizer (OF) and bio-organic fertilizer (BF) which containing beneficial microorganisms to pear trees can both significantly improve fruit quality and yield. In order to reveal the mechanism of BF and OF regulating fruit growth and quality in pear, the effects of BF and OF on the photosynthetic characteristics and the accumulation of major sugars and organic acids of the pear fruit were quantified compared with chemical fertilizer (CF). Additionally, the molecular mechanisms regulating pear fruit development and quality were studied through transcriptome analysis. The three treatments were conducted based on the same amounts of nitrogen supply. The results showed that compared with CF, BF and OF treatments increased the fruit yield, and also significantly improved the photosynthesis efficiency in pear. BF and OF both significantly increased the sucrose content but significantly decreased the fructose and glucose content within the pear fruit. The amount of malic acid was significantly higher in OF treatment. Compared with CF and OF, BF significantly increased the sugar-acid ratio and thus improved the fruit quality. Transcriptome analysis and weighted correlation network analysis (WGCNA) revealed that the sugar metabolism of fruits applied with the BF was enhanced compared with those applied with CF or OF. More specifically, the expression of SDH (Sorbitol dehydrogenase) was higher in BF, which converts sorbitol into fructose. For both of the OF and BF, the transcript abundance of sugar transporter genes was significantly increased, such as SOT (Sorbitol transporter), SUT14 (Sugar transport 14), UDP-GLUT4 (UDP-glucose transporter 4), UDP-SUT (UDP-sugar transporter), SUC4 (Sucrose transport 4), SUT7 (Sugar transporter 7), SWEET10 and SWEET15 (Bidirectional sugar transporter), which ensures sugar transportation. The genes involved in organic acid metabolism showed decreased transcripts abundance in both BF and OF treatments, such as VAP (Vesicle-associated protein) and cyACO (Cytosolic aconitase), which reduce the conversion from succinate to citric acid, and decrease the conversion from citric acid to malic acid in the TCA cycle (Tricarboxylic Acid cycle) through Pept6 (Oligopeptide transporter). In conclusion, the application of BF and OF improved fruit quality by regulating the expression of sugar and organic acid metabolism-related genes and thus altering the sugar acid metabolism. Both BF and OF promote sucrose accumulation and citric acid degradation in fruits, which may be an important reason for improving pear fruit quality. The possible mechanism of bio-organic fertilizer to improve fruit quality was discussed.

Dietary mannan oligosaccharides strengthens intestinal immune barrier function via multipath cooperation during Aeromonas Hydrophila infection in grass carp (Ctenopharyngodon Idella)

In recent years, mannose oligosaccharide (MOS) as a functional additive is widely used in aquaculture, to enhance fish immunity. An evaluation of the effect of dietary MOS supplementation on the immune barrier function and related signaling molecules mechanism of grass carp (Ctenopharyngodon idella) was undertaken in the present study. Six diets with graded amounts of MOS supplementation (0, 200, 400, 600, 800, and 1000 mg/kg) were fed to 540 grass carp over 60 days. To examine the immune response and potential mechanisms of MOS supplementation on the intestine, a challenge test was conducted using injections of Aeromonas hydrophila for 14 days. Results of the study on the optimal supplementation with MOS were found as follows (1) MOS enhances immunity partly related to increasing antibacterial substances content and antimicrobial peptides expression; (2) MOS attenuates inflammatory response partly related to regulating the dynamic balance of intestinal inflammatory cytokines; (3) MOS regulates immune barrier function may partly be related to modulating TLRs/MyD88/NFκB and TOR/S6K1/4EBP signalling pathways. Finally, the current study concluded that MOS supplementation could improve fish intestinal immune barrier function under Aeromonas hydrophila infected conditions.

Differential proteome response to H5N1 highly pathogenic avian influenza (HPAI) viruses infection in duck

Ducks and wild aquatic birds are the natural reservoirs of avian influenza viruses. However, the host proteome response that causes disease in vivo by the H5N1 HPAI virus is still unclear. This study presented a comprehensive analysis of the proteome response in Muscovy duck lung tissue during 3 days of infection with either a highly virulent DK383 or an avirulent DK212. An unbiased strategy- isobaric tags for relative and absolute quantitation (iTRAQ) in conjunction with high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) was utilized to investigate the infection mechanism. Pathways derived from analysis of 292 significantly altered proteins may contribute to the high pathogenic nature and disease progression of H5N1 viruses. Global proteome profiles indicated improved correlation with the virus titers and gene expression patterns between the two strains of the H5N1 virus. DK383 replicated more efficiently and induced a stronger response specific to severe disease. While proteins involved in the immune response of neutrophils were increased markedly by DK383, DK212 evoked a distinct response characterized by an increase in proteins involved in the maturation of dendritic cells, adhesion of phagocytes, and immune response of macrophages. The differentially activated Akt/mTOR/p70S6K pathway might involve in the host response to H5N1 viruses. Therefore, systematically integrated with datasets from primary genomic and virus titer results, proteomic analyses may help reveal the potential pathogenesis.

Advances in Vaccine Development of the Emerging Novel Genotype Fowl Adenovirus 4

Fowl adenovirus (FAdV) was first reported in Angara Goth, Pakistan, in 1987. For this reason, it is also known as “Angara disease.” It was later reported in China, Japan, South Korea, India, the United States, Canada, and other countries and regions, causing huge economic losses in the poultry industry worldwide. Notably, since June 2015, a natural outbreak of severe hydropericardium hepatitis syndrome (HHS), associated with a hypervirulent novel genotype FAdV-4 infection, has emerged in most provinces of China. The novel virus FAdV-4 spread rapidly and induced a 30-100% mortality rate, causing huge economic losses and threatening the green and healthy poultry breeding industry. Vaccines against FAdV-4, especially the emerging novel genotype, play a critical role and will be the most efficient tool for preventing and controlling HHS. Various types of FAdV-4 vaccines have been developed and evaluated, such as inactivated, live-attenuated, subunit, and combined vaccines. They have made great contributions to the control of HHS, but the details of cross-protection within FAdVs and the immunogenicity of different vaccines require further investigation. This review highlights the recent advances in developing the FAdV-4 vaccine and promising new vaccines for future research.

Neutral Polysaccharides From Hohenbuehelia serotina With Hypoglycemic Effects in a Type 2 Diabetic Mouse Model

Neutral polysaccharides (NHSPs) from the mushroom Hohenbueheliaserotina were purified by D301/D152 resin ion-exchange chromatography and DEAE-cellulose anion exchange chromatography. The weight-average molecular weight (M_W) and number-average molecular weight (Mn) of NHSP were 1,821 and 820.55 kDa, respectively. A monosaccharide component analysis showed that NHSP was composed of glucose, galactose, and mannose in molar ratio 2.6:2.1:1.0. FT-IR and NMR (¹H and HSQC) spectroscopic analyses revealed that NHSP contained mainly 1,3-linked β-D-glucose, 1,4-linked β-D-glucose, 1,6-linked β-D-mannose, 1,6-linked α-D-mannose, and 1,6-linked β-D-galactose. The thermogravimetric analysis (TGA) showed that NHSP has good thermal stability below 250°C. NHSP notably reduced the blood glucose level (hypoglycemic effect) at dose 200 mg/kg for 21 days in a type 2 diabetic mouse model. NHSP reduced the liver index significantly, suggesting that it may help prevent hepatic steatosis or hepatomegaly.

The Raf-like kinase Raf36 negatively regulates plant resistance against the oomycete pathogen Phytophthora parasitica by targeting MKK2

Oomycetes represent a unique group of plant pathogens that are phylogenetically distant from true fungi and cause significant crop losses and environmental damage. Understanding of the genetic basis of host plant susceptibility facilitates the development of novel disease resistance strategies. In this study, we report the identification of an Arabidopsis thaliana T-DNA mutant with enhanced resistance to Phytophthora parasitica with an insertion in the Raf-like mitogen-activated protein kinase kinase kinase gene Raf36. We generated additional raf36 mutants by CRISPR/Cas9 technology as well as Raf36 complementation and overexpression transformants, with consistent results of infection assays showing that Raf36 mediates Arabidopsis susceptibility to P. parasitica. Using a virus-induced gene silencing assay, we silenced Raf36 homologous genes in Nicotiana benthamiana and demonstrated by infection assays the conserved immune function of Raf36. Mutagenesis analyses indicated that the kinase activity of Raf36 is important for its immune function and interaction with MKK2, a MAPK kinase. By generating and analysing mkk2 mutants and MKK2 complementation and overexpression transformants, we found that MKK2 is a positive immune regulator in the response to P. parasitica infection. Furthermore, infection assay on mkk2 raf36 double mutant plants indicated that MKK2 is required for the raf36-conferred resistance to P. parasitica. Taken together, we identified a Raf-like kinase Raf36 as a novel plant susceptibility factor that functions upstream of MKK2 and directly targets it to negatively regulate plant resistance to P. parasitica.

New Evidence for the Existence of Two Kiss/Kissr Systems in a Flatfish Species, the Turbot (Scophthalmus maximus), and Stimulatory Effects on Gonadotropin Gene Expression

Seasonal reproduction is generally controlled by the hypothalamus-pituitary-gonadal (HPG) axis in fish. Previous studies have demonstrated that the kisspeptin (Kiss)/kisspeptin receptor (Kissr) system, a positive regulator of the HPG axis, mediates the responses to environmental cues. Turbot (Scophthalmus maximus), a representative species of Pleuronectiformes, is one of the most commercially important fish species cultured in Europe and North China. However, the mechanisms by which the Kiss/Kissr system regulates the reproductive axis of turbot according to seasonal changes, especially photoperiod, have not been clearly characterized. In the current study, the cDNA sequences of kiss2/kissr2, along with kiss1/kissr3 which was thought to be lost in flatfish species, were cloned and functionally characterized. The kiss1, kiss2, and kissr3 transcripts were highly detected in the brain and gonad, while kissr2 mRNA was only abundantly expressed in the brain. Moreover, kiss/kissr mRNAs were further examined in various brain areas of both sexes. The kiss1, kissr2, kissr3 mRNAs were highly expressed in the mesencephalon, while a substantial degree of kiss2 transcripts were observed in the hypothalamus. During annual reproductive cycle, both kiss and kissr transcript levels declined significantly from the immature to mature stages and increased at the degeneration stage in the brains of both sexes, especially in the mesencephalon and hypothalamus. The ovarian kiss1, kiss2, and kissr2 mRNA levels were highest at the vitellogenic stage (mature stage), while expression of kissr3 was highest at the immature stage. The testicular kiss and kissr transcripts were highest in the immature and degeneration stages, and lowest at the mature stage. In addition, intraperitoneal injection of Kiss1-10 and Kiss2-10 significantly stimulated mRNA levels of pituitary lhβ, fhsβ, and gthα. In summary, two Kiss/Kissr systems were firstly proven in a flatfish species of turbot, and it has a positive involvement in controlling the reproduction of the Kiss/Kissr system in turbot. The results will provide preliminary information regarding how the Kiss/Kissr system controls seasonal reproduction in turbot broodstock.

MdHB-7 Regulates Water Use Efficiency in Transgenic Apple (Malus domestica) Under Long-Term Moderate Water Deficit

Improved water use efficiency (WUE) promotes plant survival and crop yield under water deficit conditions. Although the plant-specific HD-Zip I transcription factors have important roles in plant adaptation to various abiotic stresses, including water deficit, their functions in regulating WUE of apple (Malus domestica) are poorly understood. We characterized the role of MdHB-7 in WUE regulation by subjecting MdHB-7 transgenic plants to long-term moderate soil water deficit. The long-term WUE (WUE_L) of transgenic apple plants with MdHB-7 overexpression or MdHB-7 RNA interference (RNAi) differed significantly from that of control plants. Upregulation of MdHB-7 caused reduced stomatal density, whereas the suppression of MdHB-7 increased stomatal density under both normal and long-term moderate soil water deficit conditions. Moderate reduction in stomatal density helped to improve the WUE of MdHB-7 overexpression transgenic plants, especially under water deficit conditions. MdHB-7 overexpression plants maintained high rates of photosynthesis that were conducive to the accumulation of biomass and the improvement of WUE_L. MdHB-7 overexpression also alleviated the inhibition of root growth caused by long-term moderate soil water deficit and improved root vitality and hydraulic conductivity, which were essential for improving plant WUE_L. By contrast, MdHB-7 RNA interference reduced the WUE_L of transgenic plants by inhibiting these factors under normal and long-term moderate soil water deficit conditions. Taken together, our results provide solid evidence for a crucial role of MdHB-7 in the regulation of apple WUE_L and provide new insights for improving the WUE of apple plants under moderate soil water deficit.