Selenium Nanomaterials Enhance Sheath Blight Resistance and Nutritional Quality of Rice: Mechanisms of Action and Human Health Benefit.

In the current work, the foliar application of selenium nanomaterials (Se0 NMs) suppressed sheath blight in rice (Oryza sativa). The beneficial effects were nanoscale specific and concentration dependent. Specifically, foliar amendment of 5 mg/L Se0 NMs decreased the disease severity by 68.8% in Rhizoctonia solani-infected rice; this level of control was 1.57- and 2.20-fold greater than that of the Se ions with equivalent Se mass and a commercially available pesticide (Thifluzamide). Mechanistically, (1) the controlled release ability of Se0 NMs enabled a wider safe concentration range and greater bioavailability to Se0 NMs, and (2) transcriptomic and metabolomic analyses demonstrated that Se0 NMs simultaneously promoted the salicylic acid- and jasmonic-acid-dependent acquired disease resistance pathways, antioxidative system, and flavonoid biosynthesis. Additionally, Se0 NMs improved rice yield by 31.1%, increased the nutritional quality by 6.4-7.2%, enhanced organic Se content by 44.8%, and decreased arsenic and cadmium contents by 38.7 and 42.1%, respectively, in grains as compared with infected controls. Human simulated gastrointestinal tract model results showed that the application of Se0 NMs enhanced the bioaccessibility of Se in grains by 22.0% and decreased the bioaccessibility of As and Cd in grains by 20.3 and 13.4%, respectively. These findings demonstrate that Se0 NMs can serve as an effective and sustainable strategy to increase food quality and security.

Phytoalexin sakuranetin attenuates endocytosis and enhances resistance to rice blast.

Phytoalexin sakuranetin functions in resistance against rice blast. However, the mechanisms underlying the effects of sakuranetin remains elusive. Here, we report that rice lines expressing resistance (R) genes were found to contain high levels of sakuranetin, which correlates with attenuated endocytic trafficking of plasma membrane (PM) proteins. Exogenous and endogenous sakuranetin attenuates the endocytosis of various PM proteins and the fungal effector PWL2. Moreover, accumulation of the avirulence protein AvrCO39, resulting from uptake into rice cells by Magnaporthe oryzae, was reduced following treatment with sakuranetin. Pharmacological manipulation of clathrin-mediated endocytic (CME) suggests that this pathway is targeted by sakuranetin. Indeed, attenuation of CME by sakuranetin is sufficient to convey resistance against rice blast. Our data reveals a mechanism of rice against M. oryzae by increasing sakuranetin levels and repressing the CME of pathogen effectors, which is distinct from the action of many R genes that mainly function by modulating transcription.

Hollow Mesoporous Silica Nanoparticles as a New Nanoscale Resistance Inducer for Fusarium Wilt Control: Size Effects and Mechanism of Action.

In agriculture, soil-borne fungal pathogens, especially Fusarium oxysporum strains, are posing a serious threat to efforts to achieve global food security. In the search for safer agrochemicals, silica nanoparticles (SiO2NPs) have recently been proposed as a new tool to alleviate pathogen damage including Fusarium wilt. Hollow mesoporous silica nanoparticles (HMSNs), a unique class of SiO2NPs, have been widely accepted as desirable carriers for pesticides. However, their roles in enhancing disease resistance in plants and the specific mechanism remain unknown. In this study, three sizes of HMSNs (19, 96, and 406 nm as HMSNs-19, HMSNs-96, and HMSNs-406, respectively) were synthesized and characterized to determine their effects on seed germination, seedling growth, and Fusarium oxysporum f. sp. phaseoli (FOP) suppression. The three HMSNs exhibited no side effects on cowpea seed germination and seedling growth at concentrations ranging from 100 to 1500 mg/L. The inhibitory effects of the three HMSNs on FOP mycelial growth were very weak, showing inhibition ratios of less than 20% even at 2000 mg/L. Foliar application of HMSNs, however, was demonstrated to reduce the FOP severity in cowpea roots in a size- and concentration-dependent manner. The three HMSNs at a low concentration of 100 mg/L, as well as HMSNs-19 at a high concentration of 1000 mg/L, were observed to have little effect on alleviating the disease incidence. HMSNs-406 were most effective at a concentration of 1000 mg/L, showing an up to 40.00% decline in the disease severity with significant growth-promoting effects on cowpea plants. Moreover, foliar application of HMSNs-406 (1000 mg/L) increased the salicylic acid (SA) content in cowpea roots by 4.3-fold, as well as the expression levels of SA marker genes of PR-1 (by 1.97-fold) and PR-5 (by 9.38-fold), and its receptor gene of NPR-1 (by 1.62-fold), as compared with the FOP infected control plants. Meanwhile, another resistance-related gene of PAL was also upregulated by 8.54-fold. Three defense-responsive enzymes of POD, PAL, and PPO were also involved in the HMSNs-enhanced disease resistance in cowpea roots, with varying degrees of reduction in activity. These results provide substantial evidence that HMSNs exert their Fusarium wilt suppression in cowpea plants by activating SA-dependent SAR (systemic acquired resistance) responses rather than directly suppressing FOP growth. Overall, for the first time, our results indicate a new role of HMSNs as a potent resistance inducer to serve as a low-cost, highly efficient, safe and sustainable alternative for plant disease protection.

Effects of adding Bacillus subtilis natto NTU-18 in paste feed on growth, intestinal morphology, gastrointestinal microbiota diversity, immunity, and disease resistance of Anguilla japonica glass eels.

Japanese eel, Anguilla japonica, holds significant importance in Taiwanese aquaculture. With the intensification of eel farming, the impact of Edwardsiella tarda has become increasingly severe. Consequently, the abusive use of antibiotics has risen. Bacillus subtilis natto NTU-18, a strain of Bacillus with a high survival rate in feed processing, plays a crucial role in promoting intestinal health through competitive rejection, enhancing immune responses against bacterial pathogens, and improving intestinal health by modulating gastrointestinal microbiota to produce beneficial metabolites of mice and grass carp, Ctenopharyngodon idella. This study investigated the effects of different proportions (control, 0.25 %, 0.5 %, 1 %, and 2 %) of B. subtilis natto NTU-18 added to paste feed on the growth performance, intestinal morphology, and microbiota, expression of immune-related genes, and resistance to E. tarda in Japanese glass eel. The results indicated that the growth performance of all groups with B. subtilis natto NTU-18 added was significantly higher than that of the control group and did not impact the villi morphology. The expression of immune-related genes in the kidney, specifically HSP70 and SOD, was significantly higher from 0.5 % and above than the control; however, no significant differences were observed in CAT, POD, and HSP90. In the liver, significant differences were found in HSP70 and IgM above 0.25 % compared to the control group, with no significant differences in SOD, CAT, POD, and HSP90 among all groups. Additionally, intestinal microbiota analysis revealed that the 2 % additional group had significantly lower diversity than other groups, with Cetobacterium as the dominant species. The challenge test observed that the survival rates of the 0.5 % and 1 % groups were significantly higher. This research suggests that adding 0.5 % and 1 % of B. subtilis natto NTU-18 to the diet is beneficial for Japanese glass eel's immunity, growth performance, and disease resistance.

Salicylic acid carboxyl glucosyltransferase UGT87E7 regulates disease resistance in Camellia sinensis.

Plant immune response following pathogenic infection is regulated by plant hormones, and salicylic acid (SA) and its sugar conjugates play important roles in establishing basal resistance. Here, the important pathogen Pseudopestalotiopsis camelliae-sinensis (Pcs) was isolated from tea gray blight, one of the most destructive diseases in tea plantations. Transcriptomic analysis led to the discovery of the putative Camellia sinensis UDP-glucosyltransferase CsUGT87E7 whose expression was significantly induced by SA application and Pcs infection. Recombinant CsUGT87E7 glucosylates SA with a Km value of 12 µM to form SA glucose ester (SGE). Downregulation reduced the accumulation of SGE, and CsUGT87E7-silenced tea plants exhibited greater susceptibility to pathogen infection than control plants. Similarly, CsUGT87E7-silenced tea leaves accumulated significantly less SA after infection and showed reduced expression of pathogenesis-related genes. These results suggest that CsUGT87E7 is an SA carboxyl glucosyltransferase that plays a positive role in plant disease resistance by modulating SA homeostasis through a mechanism distinct from that described in Arabidopsis (Arabidopsis thaliana). This study provides insight into the mechanisms of SA metabolism and highlights the role of SGE in the modulation of plant disease resistance.

Reserpine improves Enterobacteriaceae resistance in chicken intestine via neuro-immunometabolic signaling and MEK1/2 activation.

Salmonella enterica persist in the chicken gut by suppressing inflammatory responses via expansion of intestinal regulatory T cells (Tregs). In humans, T cell activation is controlled by neurochemical signaling in Tregs; however, whether similar neuroimmunological signaling occurs in chickens is currently unknown. In this study, we explore the role of the neuroimmunological axis in intestinal Salmonella resistance using the drug reserpine, which disrupts intracellular storage of catecholamines like norepinephrine. Following reserpine treatment, norepinephrine release was increased in both ceca explant media and Tregs. Similarly, Salmonella killing was greater in reserpine-treated explants, and oral reserpine treatment reduced the level of intestinal Salmonella Typhimurium and other Enterobacteriaceae in vivo. These antimicrobial responses were linked to an increase in antimicrobial peptide and IL-2 gene expression as well as a decrease in CTLA-4 gene expression. Globally, reserpine treatment led to phosphorylative changes in epidermal growth factor receptor (EGFR), mammalian target of rapamycin (mTOR), and the mitogen-associated protein kinase 2(MEK2). Exogenous norepinephrine treatment alone increased Salmonella resistance, and reserpine-induced antimicrobial responses were blocked using beta-adrenergic receptor inhibitors, suggesting norepinephrine signaling is crucial in this mechanism. Furthermore, EGF treatment reversed reserpine-induced antimicrobial responses, whereas mTOR inhibition increased antimicrobial activities, confirming the roles of metabolic signaling in these responses. Finally, MEK1/2 inhibition suppressed reserpine, norepinephrine, and mTOR-induced antimicrobial responses. Overall, this study demonstrates a central role for MEK1/2 activity in reserpine induced neuro-immunometabolic signaling and subsequent antimicrobial responses in the chicken intestine, providing a means of reducing bacterial colonization in chickens to improve food safety.

Sulfur-Induced Resistance against Pseudomonas syringae pv. actinidiae via Triggering Salicylic Acid Signaling Pathway in Kiwifruit.

Sulfur has been previously reported to modulate plant growth and exhibit significant anti-microbial activities. However, the mechanism underlying its diverse effects on plant pathogens has not been elucidated completely. The present study conducted the two-year field experiment of sulfur application to control kiwifruit canker from 2017 to 2018. For the first time, our study uncovered activation of plant disease resistance by salicylic acid after sulfur application in kiwifruit. The results indicated that when the sulfur concentration was 1.5-2.0 kg m-3, the induced effect of kiwifruit canker reached more than 70%. Meanwhile, a salicylic acid high lever was accompanied by the decline of jasmonic acid. Further analysis revealed the high expression of the defense gene, especially AcPR-1, which is a marker of the salicylic acid signaling pathway. Additionally, AcICS1, another critical gene of salicylic acid synthesis, was also highly expressed. All contributed to the synthesis of increasing salicylic acid content in kiwifruit leaves. Moreover, the first key lignin biosynthetic AcPAL gene was marked up-regulated. Thereafter, accumulation of lignin content in the kiwifruit stem and the higher deposition of lignin were visible in histochemical analysis. Moreover, the activity of the endochitinase activity of kiwifruit leaves increased significantly. We suggest that the sulfur-induced resistance against Pseudomonas syringae pv. actinidiae via salicylic activates systemic acquired resistance to enhance plant immune response in kiwifruit.

CaWRKY30 Positively Regulates Pepper Immunity by Targeting CaWRKY40 against Ralstonia solanacearum Inoculation through Modulating Defense-Related Genes.

The WRKY transcription factors (TFs) network is composed of WRKY TFs' subset, which performs a critical role in immunity regulation of plants. However, functions of WRKY TFs' network remain unclear, particularly in non-model plants such as pepper (Capsicum annuum L.). This study functionally characterized CaWRKY30-a member of group III Pepper WRKY protein-for immunity of pepper against Ralstonia solanacearum infection. The CaWRKY30 was detected in nucleus, and its transcriptional expression levels were significantly upregulated by R. solanacearum inoculation (RSI), and foliar application ethylene (ET), abscisic acid (ABA), and salicylic acid (SA). Virus induced gene silencing (VIGS) of CaWRKY30 amplified pepper's vulnerability to RSI. Additionally, the silencing of CaWRKY30 by VIGS compromised HR-like cell death triggered by RSI and downregulated defense-associated marker genes, like CaPR1, CaNPR1, CaDEF1, CaABR1, CaHIR1, and CaWRKY40. Conversely, transient over-expression of CaWRKY30 in pepper leaves instigated HR-like cell death and upregulated defense-related maker genes. Furthermore, transient over-expression of CaWRKY30 upregulated transcriptional levels of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. On the other hand, transient over-expression of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40 upregulated transcriptional expression levels of CaWRKY30. The results recommend that newly characterized CaWRKY30 positively regulates pepper's immunity against Ralstonia attack, which is governed by synergistically mediated signaling by phytohormones like ET, ABA, and SA, and transcriptionally assimilating into WRKY TFs networks, consisting of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. Collectively, our data will facilitate to explicate the underlying mechanism of crosstalk between pepper's immunity and response to RSI.

The resistance of peanut to soil-borne pathogens improved by rhizosphere probiotics under calcium treatment.

BACKGROUND: Peanut (Arachis hypogaea L.) is an important oil and economic crop. Calcium modulates plants in response to abiotic stresses and improves plant resistance to pathogens. Enrichment of beneficial microorganisms in the rhizosphere is associated with plant disease resistance and soil development. The purpose of this study was to analyze the differences in peanut rhizosphere microbial community structure between the calcium treatment and the control during two growth stages and to explain why calcium application could improve the resistance of peanuts to soil-borne pathogens. RESULTS: The 16S rDNA amplicon sequencing of rhizosphere microbiome showed that calcium application significantly enriched Serratia marcescens and other three dominant strains at the seedling stage. At the pod filling stage, ten dominant stains such as Sphingomonas changbaiensis and Novosphingobium panipatense were enriched by calcium. Serratia marcescens aseptic fermentation filtrate was mixed with PDA medium and inoculated with the main soil-borne pathogens in the seedling stage, which could inhibit the growth of Fusarium solani and Aspergillus flavus. The aseptic fermentation filtrate of Novosphingobium panipatense was mixed with PDA medium and inoculated with the main soil-borne pathogens in the pod filling stage, which could inhibit the growth of Sclerotium rolfsii and Leptosphaerulina arachidicola. CONCLUSIONS: Calcium application increases the resistance of peanuts to soil-borne pathogens by enriching them with specific dominant bacteria.

Cadherin Protein Is Involved in the Action of Bacillus thuringiensis Cry1Ac Toxin in Ostrinia furnacalis.

Transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal proteins have been extensively planted for insect pest control, but the evolution of Bt resistance in target pests threatens the sustainability of this approach. Mutations of cadherin in the midgut brush border membrane was associated with Cry1Ac resistance in several lepidoptera species, including the Asian corn borer, Ostrinia furnacalis, a major pest of maize in Asian-Western Pacific countries. However, the causality of O. furnacalis cadherin (OfCad) with Cry1Ac resistance remains to be clarified. In this study, in vitro and in vivo approaches were employed to examine the involvement of OfCad in mediating Cry1Ac toxicity. Sf9 cells transfected with OfCad showed significant immunofluorescent binding with Cry1Ac toxin and exhibited a concentration-dependent mortality effect when exposed to Cry1Ac. The OfCad knockout strain OfCad-KO, bearing homozygous 15.4 kb deletion of the OfCad gene generated by CRISPR/Cas9 mutagenesis, exhibited moderate-level resistance to Cry1Ac (14-fold) and low-level resistance to Cry1Aa (4.6-fold), but no significant changes in susceptibility to Cry1Ab and Cry1Fa, compared with the original NJ-S strain. The Cry1Ac resistance phenotype was inherited as autosomal, recessive mode, and significantly linked with the OfCad knockout in the OfCad-KO strain. These results demonstrate that the OfCad protein is a functional receptor for Cry1Ac, and disruption of OfCad confers a moderate Cry1Ac resistance in O. furnacalis. This study provides new insights into the mode of action of the Cry1Ac toxin and useful information for designing resistance monitoring and management strategies for O. furnacalis.

Myo-Inositol Restores Tilapia's Ability Against Infection by Aeromonas sobria in Higher Water Temperature.

Bacterial infection presents severe challenge to tilapia farming, which is largely influenced by water temperature. However, how water temperature determines tilapias' survival to infection is not well understood. Here, we address this issue from the perspective of metabolic state. Tilapias were more susceptible to Aeromonas sobria infection at 33°C than at 18°C, which is associated with differential metabolism of the fish. Compared to the metabolome of tilapia at 18°C, the metabolome at 33°C was characterized with increased an tricarboxylic acid cycle and a reduced level of myo-inositol which represent the most impactful pathway and crucial biomarker, respectively. These alterations were accompanied with the elevated transcriptional level of 10 innate immune genes with infection time, where il-1b, il-6, il-8, and il-10 exhibited a higher expression at 33°C than at 18°C and was attenuated by exogenous myo-inositol in both groups. Interestingly, exogenous myo-inositol inactivated the elevated TCA cycle via inhibiting the enzymatic activity of succinate dehydrogenase and malate dehydrogenase. Thus, tilapias showed a higher survival ability at 33°C. Our study reveals a previously unknown relationship among water temperature, metabolic state, and innate immunity and establishes a novel approach to eliminate bacterial pathogens in tilapia at higher water temperature.

Effects of dietary quercetin on the innate immune response and resistance to white spot syndrome virus in Procambarusclarkii.

In recent years, the use of natural products with immune-stimulating and antimicrobial properties has attracted increasing attention in aquaculture researches. In our study, the effect of diet supplemented with quercetin, a flavonoid commonly found in some types of plants substance on the innate immune response and disease resistance in crayfish (Procambarus clarkii) against white spot syndrome virus (WSSV) is reported. It was found that dietary 40 mg/kg quercetin significantly reduced the mortality of crayfish and WSSV copy number after WSSV challenge. Dietary quercetin increased catalase (CAT), and lysozyme (LZM) activity in crayfish. Dietary quercetin increased the expression of NF-κB, anti-lipopolysaccharide factor (ALF) and toll-like receptor (TLR) genes in crayfish. The apoptosis rate of hemocyte was increased by quercetin supplement in crayfish. Our results suggest that dietary quercetin may affect the innate immunity of crayfish and protect crayfish from WSSV infection.

Identification of a Chitooligosaccharide Mechanism against Bacterial Leaf Blight on Rice by In Vitro and In Silico Studies.

This study focuses on a commercial plant elicitor based on chitooligosaccharides (BIG®), which aids in rice plant growth and disease resistance to bacterial leaf blight (BLB). When the pathogen (Xoo) vigorously attacks rice that has suffered yield losses, it can cause damage in up to 20% of the plant. Furthermore, Xoo is a seed-borne pathogen that can survive in rice seeds for an extended period. In this study, when rice seeds were soaked and sprayed with BIG®, there was a significant increase in shoot and root length, as well as plant biomass. Furthermore, BIG®-treated rice plants showed a significant reduction in BLB severity of more than 33%. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) analysis was used to characterize BIG®'s mechanism in the chemical structure of rice leaves. The SR-FTIR results at 1650, 1735, and 1114 cm-1 indicated changes in biochemical components such as pectins, lignins, proteins, and celluloses. These findings demonstrated that commercial BIG® not only increased rice growth but also induced resistance to BLB. The drug's target enzyme, Xoo 1075 from Xanthomonas oryzae (PDB ID: 5CY8), was analyzed for its interactions with polymer ingredients, specifically chitooligosaccharides, to gain molecular insights down to the atomic level. The results are intriguing, with a strong binding of the chitooligosaccharide polymer with the drug target, revealing 10 hydrogen bonds between the protein and polymer. Overall, the computational analysis supported the experimentally demonstrated strong binding of chitooligosaccharides to the drug target.

Chickpea shows genotype-specific nodulation responses across soil nitrogen environment and root disease resistance categories.

BACKGROUND: The ability of chickpea to obtain sufficient nitrogen via its symbiotic relationship with Mesorhizobium ciceri is of critical importance in supporting growth and grain production. A number of factors can affect this symbiotic relationship including abiotic conditions, plant genotype, and disruptions to host signalling/perception networks. In order to support improved nodule formation in chickpea, we investigated how plant genotype and soil nutrient availability affect chickpea nodule formation and nitrogen fixation. Further, using transcriptomic profiling, we sought to identify gene expression patterns that characterize highly nodulated genotypes. RESULTS: A study involving six chickpea varieties demonstrated large genotype by soil nitrogen interaction effects on nodulation and further identified agronomic traits of genotypes (such as shoot weight) associated with high nodulation. We broadened our scope to consider 29 varieties and breeding lines to examine the relationship between soilborne disease resistance and the number of nodules developed and real-time nitrogen fixation. Results of this larger study supported the earlier genotype specific findings, however, disease resistance did not explain differences in nodulation across genotypes. Transcriptional profiling of six chickpea genotypes indicates that genes associated with signalling, N transport and cellular localization, as opposed to genes associated with the classical nodulation pathway, are more likely to predict whether a given genotype will exhibit high levels of nodule formation. CONCLUSIONS: This research identified a number of key abiotic and genetic factors affecting chickpea nodule development and nitrogen fixation. These findings indicate that an improved understanding of genotype-specific factors affecting chickpea nodule induction and function are key research areas necessary to improving the benefits of rhizobial symbiosis in chickpea.

The role of salicylic acid and benzothiadiazole in decreasing phytoplasma titer of sugarcane white leaf disease.

The objective of this research was to study the effect of Benzothiadiazole (BTH) and Salicylic acid (SA) on the systemic acquired resistance (SAR) of sugarcane the phytoplasma associated with the sugarcane white leaf (SCWL) disease. The experiment was conducted on plants of the sugarcane variety Khon Kaen 3 (KK3) infected with SCWL phytoplasma using insect vectors. Biochemical changes related to the SAR such as SA and total phenolic compounds were followed according to 4 different timepoints: 7, 14, 21 and 28 days after inoculation. Together, phytoplasma were quantified by RT-qPCR using the secA gene of phytoplasma. According to our results, the spraying of BTH and SA tended to increase the amounts of SA, total phenolic compounds and a lower presence of phytoplasma in the plants in comparison with the inoculated control. Spraying BTH at a concentration of 2.4 mM and SA at a concentration of 2.4 mM exhibited the best efficiency to reduce the concentration of phytoplasma. According to RT-qPCR results, the inoculated plants sprayed with BTH displayed a significantly lower concentration of phytoplasma compared to the inoculated controls. Overall, our results indicated that the spray of BTH and SA could induce an efficient SAR response to the phytoplasma associated with the SCWL disease. We expect these results will give support to the development of new products for controlling white leaf disease in sugarcane.

Fitness Costs of Chlorantraniliprole Resistance Related to the SeNPF Overexpression in the Spodoptera exigua (Lepidoptera: Noctuidae).

Spodopteraexigua, a multifeeding insect pest, has developed a high level of resistance to chlorantraniliprole, which is a benzoylurea insecticide that targets the ryanodine receptors (RyRs). Herein, the resistant strain (SE-Sel) and sensitive strain (SE-Sus) were obtained by bidirectional screening for six generations. The potential oviposited eggs and oviposition rate of the SE-Sel strain were dramatically lower than those of the SE-Sus strain; on the contrary, the weights of prepupae and preadult were significantly increased. As a post-mating response, the higher number of non-oviposited eggs in the SE-Sel strain was caused by a lower mating rate. In addition, the expression levels of vitellogenin (SeVg) and its receptor (SeVgR) in the SE-Sel strain were consistently lower than those in the SE-Sus strain. An RyRI4743M mutation, contributing to the resistance to chlorantraniliprole, was located in the S3 transmembrane segments and might have affected the release of calcium ions; it led to the upregulated expression of the neuropeptide SeNPF and its receptor SeNPFR, and the mating and oviposition rate were significantly recovered when the SeNPF was knocked down though RNA interference (RNAi) in the male adult of the SE-Sel strain. Moreover, the expression of the juvenile hormone-binding proteins SeJHBWDS3 and SeJHBAN in the male adult of the SE-Sel strain was significantly decreased, which proved the existence of a fitness cost from another angle. Therefore, these results indicate that the fitness cost accompanied by chlorantraniliprole resistance in S. exigua may be related to the decrease in mating desire due to SeNPF overexpression.

Modulation of growth, innate immunity, and disease resistance of Nile tilapia (Oreochromis niloticus) culture under biofloc system by supplementing pineapple peel powder and Lactobacillus plantarum.

Eight weeks feeding experiment was managed to evaluate the impacts of dietary addition of pineapple peel powder (PAPP) and Lactobacillus plantarum CR1T5 (LP) individual or mixed on growth performance, skin mucus and serum immunities, as well as disease resistance of Nile tilapia. Fish (average weight 20.91 ± 0.11 g) were fed four diets: Diet 1 (0 g kg-1 PAPP and 0 CFU g-1 L. plantarum, Diet 2 (10 g kg-1 PAPP), Diet 3 (108 CFU g-1L. plantarum), and Diet 4 (10 g kg-1 PAPP + 108 CFU g-1L. plantarum). Serum and mucus immune responses, as well as growth rate, were assessed every 4 weeks. Ten fish were chosen for the challenge test with Streptococcus agalactiae after 8 weeks post-feeding. The findings showed that PAPP and/or LP diets increased (P ≤ 0.05) growth performance, skin mucus, and serum immune responses. The best data were obtained in fish fed a mixture of PAPP and LP. Nevertheless, no variation (P > 0.05) was recorded between groups fed PAPP or LP. The relative survival percentage (RSP, %) in Diet 2, Diet 3, and Diet 4 was 46.15%, 50.0%, and 73.08%. Fish fed mixture of PAPP + LP recorded the best (P < 0.05) survival rate versus other treatments. The current findings recommended using a mixture of PAPP and LP as promising functional additives for aquaculture practice.

NK-lysin peptides ameliorate viral encephalopathy and retinopathy disease signs and provide partial protection against nodavirus infection in European sea bass.

Antimicrobial peptides (AMP) comprise a wide range of small molecules with direct antibacterial activity and immunostimulatory role and are proposed as promising substitutes of the antibiotics. Additionally, they also exert a role against other pathogens such as viruses and fungi less evaluated. NK-lysin, a human granulysin orthologue, possess a double function, taking part in the innate immunity as AMP and also as direct effector in the cell-mediated cytotoxic (CMC) response. This molecule is suggested as a pivotal molecule involved in the defence upon nervous necrosis virus (NNV), an epizootic virus provoking serious problems in welfare and health status in Asian and Mediterranean fish destined to human consumption. Having proved that NK-lysin derived peptides (NKLPs) have a direct antiviral activity against NNV in vitro, we aimed to evaluate their potential use as a prophylactic treatment for European sea bass (Dicentrarchus labrax), one of the most susceptible cultured-fish species. Thus, intramuscular injection of synthetic NKLPs resulted in a very low transcriptional response of some innate and adaptive immune markers. However, the injection of NKLPs ameliorated disease signs and increased fish survival upon challenge with pathogenic NNV. Although NKLPs showed promising results in treatments against NNV, more efforts are needed to understand their mechanisms of action and their applicability to the aquaculture industry.

Changing light promotes isoflavone biosynthesis in soybean pods and enhances their resistance to mildew infection.

Mildew severely reduces soybean yield and quality, and pods are the first line of defence against pathogens. Maize-soybean intercropping (MSI) reduces mildew incidence on soybean pods; however, the mechanism remains unclear. Changing light (CL) from maize shading is the most important environmental feature in MSI. We hypothesized that CL affects isoflavone accumulation in soybean pods, affecting their disease resistance. In the present study, shading treatments were applied to soybean plants during different developmental stages according to various CL environments under MSI. Chlorophyll fluorescence imaging (CFI) and classical evaluation methods confirmed that CL, especially vegetative stage shading (VS), enhanced pod resistance to mildew. Further metabolomic analyses and exogenous jasmonic acid (JA) and biosynthesis inhibitor experiments revealed the important relationship between JA and isoflavone biosynthesis, which had a synergistic effect on the enhanced resistance of CL-treated pods to mildew. VS promoted the biosynthesis and accumulation of constitutive isoflavones upstream of the isoflavone pathway, such as aglycones and glycosides, in soybean pods. When mildew infects pods, endogenous JA signalling stimulated the biosynthesis of downstream inducible malonyl isoflavone (MIF) and glyceollin to improve pod resistance.

The phenylpropanoid pathway inhibitor piperonylic acid induces broad-spectrum pest and disease resistance in plants.

Although many phenylpropanoid pathway-derived molecules act as physical and chemical barriers to pests and pathogens, comparatively little is known about their role in regulating plant immunity. To explore this research field, we transiently perturbed the phenylpropanoid pathway through application of the CINNAMIC ACID-4-HYDROXYLASE (C4H) inhibitor piperonylic acid (PA). Using bioassays involving diverse pests and pathogens, we show that transient C4H inhibition triggers systemic, broad-spectrum resistance in higher plants without affecting growth. PA treatment enhances tomato (Solanum lycopersicum) resistance in field and laboratory conditions, thereby illustrating the potential of phenylpropanoid pathway perturbation in crop protection. At the molecular level, transcriptome and metabolome analyses reveal that transient C4H inhibition in tomato reprograms phenylpropanoid and flavonoid metabolism, systemically induces immune signalling and pathogenesis-related genes, and locally affects reactive oxygen species metabolism. Furthermore, C4H inhibition primes cell wall modification and phenolic compound accumulation in response to root-knot nematode infection. Although PA treatment induces local accumulation of the phytohormone salicylic acid, the PA resistance phenotype is preserved in tomato plants expressing the salicylic acid-degrading NahG construct. Together, our results demonstrate that transient phenylpropanoid pathway perturbation is a conserved inducer of plant resistance and thus highlight the crucial regulatory role of this pathway in plant immunity.