Regulation Of Defense Responses Research Articles

Mythimna separata herbivory primes Coix resistance in systemic leaves.

Coix lacryma-jobi L. belongs to family Poaceae, is widely cultivated in tropical Asian countries for its nutritional and medicinal values. Coix is often threatened by lepidopteran such as Mythimna separata during its life cycle, resulting in severe yield reduction. Insect feeding can trigger defense signaling and increased defense responses in many other crops, yet little is known about whether simulated armyworm feeding on Coix leaves could induce anti-herbivory responses and whether armyworm feeding could activate priming in systemic leaves. In this study, Mythimna separata simulated herbivory elicited increased jasmonic acid (JA) level, JA-Ile (JA-isoleucine conjugate) and altered transcriptome in the Coix leaves. Meanwhile, M. separata simulated herbivory in local leaves primed the systemic leaves for increased accumulation of jasmonic acid and enhanced resistance to M. separata. Consistently, transcriptome analysis showed the systemic leaves were primed, which were up- or down-regulated comparing with the non-primed systemic leaves. In this study, we first reported Mythimna separata simulated herbivory induced increased defense response in leaves of Coix, also Mythimna separata herbivory primed Coix resistance in systemic leaves. This study provides new insight into the regulation of defense responses of Coix against M. separata and the ecological function of priming in Coix.

Effect of exogenous melatonin on growth and antioxidant system of pumpkin seedlings under waterlogging stress.

Melatonin regulates defense responses in plants under environmental stress. This study aimed to explore the impact of exogenous melatonin on the phenotype and physiology of 'BM1' pumpkin seedlings subjected to waterlogging stress. Waterlogging stress was induced following foliar spraying of melatonin at various concentrations (CK, 0, 10, 100, 200, and 300 μmol·L-1). The growth parameters, malondialdehyde (MDA) content, antioxidant enzyme activity, osmoregulatory substance levels, and other physiological indicators were assessed to elucidate the physiological mechanisms underlying the role of exogenous melatonin in mitigating waterlogging stress in pumpkin seedlings. The results indicate that pumpkin seedlings exhibit waterlogging symptoms, such as leaf wilting, water loss, edge chlorosis, and fading, under waterlogging stress conditions. Various growth indicators of the seedlings, including plant height, stem diameter, root length, fresh and dry weight, and leaf chlorophyll content, were significantly reduced. Moreover, the MDA content in leaves and roots increased significantly, along with elevated activities of superoxide dismutase, catalase, peroxidase, and soluble protein contents. When different concentrations of melatonin were sprayed on the leaves post waterlogging stress treatment, pumpkin seedlings showed varying degrees of recovery, with the 100 μmol·L-1 treatment displaying the best growth status and plant morphological phenotypes. There were no significant differences compared to the control group. Seedling growth indicators, chlorophyll content, root activity, antioxidant enzyme activities, soluble protein content, and osmotic adjustment substance content all increased to varying degrees with increasing melatonin concentration, peaking at 100 μmol·L-1. Melatonin also reduced membrane damage caused by oxidative stress and alleviated osmotic imbalance. Exogenous melatonin enhanced the activities of antioxidant enzymes and systems involved in scavenging reactive oxygen species, with 100 μmol·L-1 as the optimal concentration. These findings underscore the crucial role of exogenous melatonin in alleviating waterlogging stress in pumpkins. The findings of this study offer a theoretical framework and technical assistance for cultivating waterlogging-resistant pumpkins in practical settings. Additionally, it establishes a theoretical groundwork for the molecular breeding of pumpkins with increased tolerance to waterlogging.

Alterations in Gene Expression during Incompatible Interaction between Amendoim Cavalo Common Bean and Colletotrichum lindemuthianum.

Anthracnose, caused by the fungus Colletotrichum lindemuthianum, poses a significant and widespread threat to the common bean crop. The use of plant genetic resistance has proven to be the most effective strategy for managing anthracnose disease. The Amendoim Cavalo (AC) Andean cultivar has resistance against multiple races of C. lindemuthianum, which is conferred by the Co-AC gene. Fine mapping of this resistance gene to common bean chromosome Pv01 enabled the identification of Phvul.001G244300, Phvul.001G244400, and Phvul.001G244500 candidate genes for further validation. In this study, the relative expression of Co-AC candidate genes was assessed, as well as other putative genes in the vicinity of this locus and known resistance genes, in the AC cultivar following inoculation with the race 73 of C. lindemuthianum. Gene expression analysis revealed significantly higher expression levels of Phvul.001G244500. Notably, Phvul.001G244500 encodes a putative Basic Helix-Loop-Helix transcription factor, suggesting its involvement in the regulation of defense responses. Furthermore, a significant modulation of the expression of defense-related genes PR1a, PR1b, and PR2 was observed in a time-course experiment. These findings contribute to the development of improved strategies for breeding anthracnose-resistant common bean cultivars, thereby mitigating the impact of this pathogen on crop yields and ensuring sustainable bean production.

Screening for disease resistance and profiling the expression of defense-related genes contributing to resistance against bacterial blight (Xanthomonas oryzae pv. oryzae) in rice genotypes

Bacterial Bight profoundly affects global rice-growing regions. Breeding resistant cultivars is a reliable, effective, and eco-friendly way to control bacterial blight. The study was conducted during 2021–2022 to evaluate the resistance of rice genotypes to bacterial blight under glasshouse conditions. A total of 137 rice genotypes were screened for their resistance against two Xanthomonas oryzae pv. oryzae strains (TXO01 and TXO08) using the leaf clipping method. The results revealed diverse disease reactions among the genotypes, with some exhibiting high levels of resistance characterized by hypersensitive reactions and shorter lesion lengths. To further investigate the genetic basis of resistance, we screened moderately resistant and resistant genotypes for major bacterial blight resistance genes, including Xa21, xa5, and xa13, using gene-specific markers. Five genotypes viz., ADT55, CB MAS 13056, CB MAS 13060, CB MAS 13066, and ACM 18234 confirmed the presence of all R genes in a homozygous state, indicating a potentially robust resistance background. In addition, we examined the expression patterns of five defense-related genes involved in the salicylic acid (SA) and jasmonic acid (JA) signaling pathways using quantitative real-time PCR (qRT-PCR). The resistant genotypes exhibited significantly elevated expression levels of OsNPR1, OsWRKY45, OsPAL1, OsPR1a, and OsPR10a, ranging from 2 to 20-fold changes compared with the susceptible genotype. In conclusion, our findings suggest that the resistant genotypes not only harbor multiple bacterial blight resistance genes but also manifest up regulated defense responses against Xanthomonas oryzae pv. oryzae, possibly substantiating their elevated level of disease resistance.

Chimeric mutations in grapevine ENHANCED DISEASE RESISTANCE1 improve resistance to powdery mildew without growth penalty.

Grapevine (Vitis vinifera L.) incurs severe quality degradation and yield loss from powdery mildew, a major fungal disease caused by Erysiphe necator. ENHANCED DISEASE RESISTANCE1 (EDR1), a Raf-like mitogen-activated protein kinase kinase kinase, negatively regulates defense responses against powdery mildew in Arabidopsis (Arabidopsis thaliana). However, little is known about the role of the putatively orthologous EDR1 gene in grapevine. In this study, we obtained grapevine VviEDR1-edited lines using CRISPR/Cas9. Plantlets containing homozygous and bi-allelic indels in VviEDR1 developed leaf lesions shortly after transplanting into the soil and died at the seedling stage. Transgenic plants expressing wild-type VviEDR1 and mutant Vviedr1 alleles as chimera (designated as VviEDR1-chi) developed normally and displayed enhanced resistance to powdery mildew. Interestingly, VviEDR1-chi plants maintained a spatiotemporally distinctive pattern of VviEDR1 mutagenesis: while almost no mutations were detected from terminal buds, ensuring normal function of the apical meristem, mutations occurred in young leaves and increased as leaves matured, resulting in resistance to powdery mildew. Further analysis showed that the resistance observed in VviEDR1-chi plants was associated with callose deposition, increased production of salicylic acid and ethylene, H2O2 production and accumulation, and host cell death. Surprisingly, no growth penalty was observed with VviEDR1-chi plants. Hence, this study demonstrated a role of VviEDR1 in the negative regulation of resistance to powdery mildew in grapevine and provided an avenue for engineering powdery mildew resistance in grapevine.

Comprehensive analysis of MAPK gene family in upland cotton (Gossypium hirsutum) and functional characterization of GhMPK31 in regulating defense response to insect infestation

Key messageThe transcriptomic, phenotypic and metabolomic analysis of transgenic plants overexpressing GhMPK31 in upland cotton revealed the regulation of H2O2 burst and the synthesis of defensive metabolites by GhMPK31.Mitogen-activated protein kinases (MAPKs) are a crucial class of protein kinases, which play an essential role in various biological processes in plants. Upland cotton (G. hirsutum) is the most widely cultivated cotton species with high economic value. To gain a better understanding of the role of the MAPK gene family, we conducted a comprehensive analysis of the MAPK gene family in cotton. In this study, a total of 55 GhMPK genes were identified from the whole genome of G. hirsutum. Through an investigation of the expression patterns under diverse stress conditions, we discovered that the majority of GhMPK family members demonstrated robust responses to abiotic stress, pathogen stress and pest stress. Furthermore, the overexpression of GhMPK31 in cotton leaves led to a hypersensitive response (HR)-like cell death phenotype and impaired the defense capability of cotton against herbivorous insects. Transcriptome and metabolomics data analysis showed that overexpression of GhMPK31 enhanced the expression of H2O2-related genes and reduced the accumulation of defensive related metabolites. The direct evidence of GhMPK31 interacting with GhRBOHB (H2O2-generating protein) were found by Y2H, BiFC, and LCI. Therefore, we propose that the increase of H2O2 content caused by overexpression of GhMPK31 resulted in HR-like cell death in cotton leaves while reducing the accumulation of defensive metabolites, ultimately leading to a decrease in the defense ability of cotton against herbivorous insects. This study provides valuable insights into the function of MAPK genes in plant resistance to herbivorous insects.

Metabolomic insights into the browning inhibition of fresh-cut apple by hydrogen sulfide

Hydrogen sulfide (H2S) is known to effectively inhibit the browning of fresh-cut apples, but the mechanism at a metabolic level remains unclear. Herein, non-targeted metabolomics was used to analyze metabolic changes in surface and internal tissues of fresh-cut apple after H2S treatment. The results showed that prenol lipids were the most up-accumulated differential metabolites in both surface and inner tissue of fresh-cut apple during browning process, which significantly down-accumulated by H2S treatment. H2S treatment reduced the consumption of amino acid in surface tissue. Regarding inner tissue, H2S activated defense response through accumulation of lysophospholipid signaling and induced the biosynthesis of phenolic compounds. We therefore propose that H2S inhibited the surface browning of fresh-cut apple by reducing the accumulation of prenol lipids, directly delaying amino acid consumption in surface tissue and indirectly regulating defense response in inner tissue, which provides fundamental insights into browning inhibition mechanisms by H2S.

Investigation on comparative transcriptome profiling of resistant and susceptible non-CMS maize genotypes during Bipolaris maydis race O infection

Maydis leaf blight is a significant disease of maize caused by Bipolaris maydis race T, O and C. Molecular mechanisms regulating defense responses in non-CMS maize towards race O fungus are not fully known. In the present investigation, comparative transcriptome profiling was conducted on a highly resistant maize genotype SC-7-2-1-2-6-1 against a standard susceptible variety CM 119 at 48 h post inoculation (h PI) along with non-infected control. mRNA sequencing generated 38.4 Gb data, where 9349602 reads were mapped uniquely in SC-7, whereas 2714725 reads were mapped uniquely in CM-119. In inoculated SC-7, the total number of differentially expressed genes (DEGs) against control was 1413, where 1011 were up-regulated, and 402 were down-regulated. In susceptible inoculated genotype CM 119, the number of DEGs against control was 2902, where 1703 were up-, and 1199 were down-regulated. DEGs between inoculated resistant and susceptible genotypes were 10745, where 5343 were up-, and 5402 were down-regulated. The RNA-seq data were validated using RT-qPCR. The key findings are that SC-7 poses a robust plant signaling system mainly induced by oxidation–reduction process and calcium-mediated signaling. It regulates its fitness-related genes efficiently, viz., aldolase 2 gene, isopropanoid, phyto hormones, P450 cytochrome, amino acid synthesis, nitrogen assimilation genes etc. These findings showed more transcriptional changes in the SC-7 genotype, which contains many defence-related genes. They can be explored in future crop development programmes to combat multiple maize diseases. The current finding provides information to elucidate molecular and cellular processes occurring in maize during B. maydis race O infection.

Identification of novel biomarkers based on lipid metabolism-related molecular subtypes for moderately severe and severe acute pancreatitis.

Acute pancreatitis (AP) is an unpredictable and potentially fatal disorder. A derailed or unbalanced immune response may be the root of the disease's severe course. Disorders of lipid metabolism are highly correlated with the occurrence and severity of AP. We aimed to characterize the contribution and immunological characteristics of lipid metabolism-related genes (LMRGs) in non-mild acute pancreatitis (NMAP) and identify a robust subtype and biomarker for NMAP. The expression mode of LMRGs and immune characteristics in NMAP were examined. Then LMRG-derived subtypes were identified using consensus clustering. The weighted gene co-expression network analysis (WGCNA) was utilized to determine hub genes and perform functional enrichment analyses. Multiple machine learning methods were used to build the diagnostic model for NMAP patients. To validate the predictive effectiveness, nomograms, receiver operating characteristic (ROC), calibration, and decision curve analysis (DCA) were used. Using gene set variation analysis (GSVA) and single-cell analysis to study the biological roles of model genes. Dysregulated LMRGs and immunological responses were identified between NMAP and normal individuals. NMAP individuals were divided into two LMRG-related subtypes with significant differences in biological function. The cluster-specific genes are primarily engaged in the regulation of defense response, T cell activation, and positive regulation of cytokine production. Moreover, we constructed a two-gene prediction model with good performance. The expression of CARD16 and MSGT1 was significantly increased in NMAP samples and positively correlated with neutrophil and mast cell infiltration.GSVA results showed that they are mainly upregulated in the T cell receptor complex, immunoglobulin complex circulating, and some immune-related routes. Single-cell analysis indicated that CARD16 was mainly distributed in mixed immune cells and macrophages, and MGST1 was mainly distributed in exocrine glandular cells. This study presents a novel approach to categorizing NMAP into different clusters based on LMRGs and developing a reliable two-gene biomarker for NMAP.

The Analysis of Short-Term Differential Expression of Transcription Factor Family Genes in Diploid and Tetraploid Rice (Oryza sativa L.) Varieties during Blast Fungus Infection

The necessity to understand plant adaptations to environmental stressors is underscored by the role of polyploidy in species evolution. This study focuses on the superior stress resistance exhibited by autotetraploid rice, which arises from chromosome doubling, in comparison to its diploid donor. We provide a quantitative analysis that highlights the differing susceptibilities of diploid (GFD-2X) and autotetraploid (GFD-4X) rice to rice blast disease, with GFD-2X being significantly more susceptible. Our investigation centers on transcription factors (TFs), which are crucial in regulating biological stress responses, by analyzing their expression in the face of a pathogen attack. This study uncovers variations in the number and expression timing of differentially expressed TF genes, providing a quantitative view of GFD-4X’s resistance. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses confirm the role of specific pathways, including “response to stimulus” and the “MAPK signaling pathway,” in resistance mechanisms. An extensive analysis of protein–protein interaction networks further clarifies the complex role of TFs during stress responses. The rationale for our experimental approach is rooted in the imperative to decipher the molecular basis of disease resistance across different ploidies, which has implications for crop enhancement. The conclusion from our research is that autotetraploid rice has a unique and more effective defense response regulation system, facilitated by transcription factors, when faced with rice blast disease. This finding provides a foundation for future genetic strategies aimed at improving crop resistance.

Anti‐inflammatory biochemical mechanisms of lithium in hippocampal tissue of triple transgenic animals for Alzheimer’s disease

AbstractBackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder of multifactorial etiology. The toxicity of senile plaques and neurofibrillary tangles are associated with structural changes that lead to brain tissue atrophy. Pro‐inflammatory cytokines are present in abnormal amounts and this accelerates the progression of the disease. Our objective is to determine the proteins of the ontological pathways, identified in the proteome, altered in the hippocampus of 3xTg‐AD animals chronically treated with lithium at therapeutic and subtherapeutic doses.Method48 (3xTg‐AD;Tg) will be used. The animals received lily for 8 months of treatment and were divided into 3 groups (control, Li 1mM and Li2 mM). The hippocampal tissue was subjected to the proteome. The inflammatory pathways of the identified proteins will be compared by Gene Ontology, using the ClueGO software. Ethics Committee (1876/2022).ResultThe genes of the Toll‐Likes receptor family was analyzed into the STRING bioinformatics program, in order to study the ontological pathways and molecular function. As parameters, we set the significance at 0.7 with the limitation of 50 interactions per gene. Thus, the results demonstrate that the ontological alterations are: immune response‐activating signal transduction, activation of immune response, regulation of defense response, positive regulation of immune response, regulation of response to stress, immune response, positive regulation of response to stimulus and immune system processConclusionThe results seem promising for understanding the inflammatory pathways related to toll‐likes. However, the results with the hippocampus tissues are under analysis.

Mycobacteria modulate SUMOylation to suppresses protective responses in dendritic cells.

Post translational modifications (PTMs) are exploited by various pathogens in order to escape host immune responses. SUMOylation is one of the PTMs which is involved in regulation of a variety of cellular responses. However, the effects of host SUMOylation on pathogenic bacteria largely remain elusive. We, therefore, investigated the role of SUMOylation in regulating defense responses in dendritic cells (DCs) during mycobacterial infection. Dendritic Cells of female BALB/c mice and THP-1 macrophages were used. Western blotting was performed to measure the expression of level of SUMO1, pSTAT1, pp38, pERK, Beclin-1, LC3, Bax and Cytochrome C. For bacterial burden confocal microscopy and CFU (Colony Forming Unit) were used. Flow cytometry was used for ROS and co-stimulatory molecules measurement. Cytokine level were measured using ELISA. We show that stimulation of Bone Marrow Derived Dendritic Cells (BMDCs) with mycobacterial antigen Rv3416 or live infection with Mycobacterium bovis BCG increases the SUMOylation of host proteins. Inhibition of SUMOylation significantly decreased intracellular bacterial loads in DCs. Additionally, inhibiting SUMOylation, induces protective immune responses by increasing oxidative burst, pro-inflammatory cytokine expression and surface expression of T cell co-stimulatory molecules, and activation of pSTAT1 and Mitogen Activated Protein Kinases (MAPK) proteins- pp38 and pERK. SUMOylation inhibition also increased apoptosis and autophagy in BMDCs. Intriguingly, mycobacteria increased SUMOylation of many of the above molecules. Furthermore, inhibiting SUMOylation in DCs primed T cells that in turn attenuated bacterial burden in infected macrophages. These findings demonstrate that SUMOylation pathway is exploited by mycobacteria to thwart protective host immune responses.

Identification of the biological processes, immune cell landscape, and hub genes shared by acute anaphylaxis and ST-segment elevation myocardial infarction.

Background: Patients with anaphylaxis are at risk for ST-segment elevation myocardial infarction (STEMI). However, the pathological links between anaphylaxis and STEMI remain unclear. Here, we aimed to explore shared biological processes, immune effector cells, and hub genes of anaphylaxis and STEMI. Methods: Gene expression data for anaphylactic (GSE69063) and STEMI (GSE60993) patients with corresponding healthy controls were pooled from the Gene Expression Omnibus database. Differential expression analysis, enrichment analysis, and CIBERSORT were used to reveal transcriptomic signatures and immune infiltration profiles of anaphylaxis and STEMI, respectively. Based on common differentially expressed genes (DEGs), Gene Ontology analysis, cytoHubba algorithms, and correlation analyses were performed to identify biological processes, hub genes, and hub gene-related immune cells shared by anaphylaxis and STEMI. The robustness of hub genes was assessed in external anaphylactic (GSE47655) and STEMI (GSE61144) datasets. Furthermore, a murine model of anaphylaxis complicated STEMI was established to verify hub gene expressions. The logistic regression analysis was used to evaluate the diagnostic efficiency of hub genes. Results: 265 anaphylaxis-related DEGs were identified, which were associated with immune-inflammatory responses. 237 STEMI-related DEGs were screened, which were involved in innate immune response and myeloid leukocyte activation. M0 macrophages and dendritic cells were markedly higher in both anaphylactic and STEMI samples compared with healthy controls, while CD4+ naïve T cells and CD8+ T cells were significantly lower. Enrichment analysis of 33 common DEGs illustrated shared biological processes of anaphylaxis and STEMI, including cytokine-mediated signaling pathway, response to reactive oxygen species, and positive regulation of defense response. Six hub genes were identified, and their expression levels were positively correlated with M0 macrophage abundance and negatively correlated with CD4+ naïve T cell abundance. In external anaphylactic and STEMI samples, five hub genes (IL1R2, FOS, MMP9, DUSP1, CLEC4D) were confirmed to be markedly upregulated. Moreover, experimentally induced anaphylactic mice developed impaired heart function featuring STEMI and significantly increased expression of the five hub genes. DUSP1 and CLEC4D were screened as blood diagnostic biomarkers of anaphylaxis and STEMI based on the logistic regression analysis. Conclusion: Anaphylaxis and STEMI share the biological processes of inflammation and defense responses. Macrophages, dendritic cells, CD8+ T cells, and CD4+ naïve T cells constitute an immune cell population that acts in both anaphylaxis and STEMI. Hub genes (DUSP1 and CLEC4D) identified here provide candidate genes for diagnosis, prognosis, and therapeutic targeting of STEMI in anaphylactic patients.

BSR1, a Rice Receptor-like Cytoplasmic Kinase, Positively Regulates Defense Responses to Herbivory.

Crops experience herbivory by arthropods and microbial infections. In the interaction between plants and chewing herbivores, lepidopteran larval oral secretions (OS) and plant-derived damage-associated molecular patterns (DAMPs) trigger plant defense responses. However, the mechanisms underlying anti-herbivore defense, especially in monocots, have not been elucidated. The receptor-like cytoplasmic kinase Broad-Spectrum Resistance 1 (BSR1) of Oryza sativa L. (rice) mediates cytoplasmic defense signaling in response to microbial pathogens and enhances disease resistance when overexpressed. Here, we investigated whether BSR1 contributes to anti-herbivore defense responses. BSR1 knockout suppressed rice responses triggered by OS from the chewing herbivore Mythimna loreyi Duponchel (Lepidoptera: Noctuidae) and peptidic DAMPs OsPeps, including the activation of genes required for biosynthesis of diterpenoid phytoalexins (DPs). BSR1-overexpressing rice plants exhibited hyperactivation of DP accumulation and ethylene signaling after treatment with simulated herbivory and acquired enhanced resistance to larval feeding. As the biological significance of herbivory-induced accumulation of rice DPs remains unexplained, their physiological activities in M. loreyi were analyzed. The addition of momilactone B, a rice DP, to the artificial diet suppressed the growth of M. loreyi larvae. Altogether, this study revealed that BSR1 and herbivory-induced rice DPs are involved in the defense against chewing insects, in addition to pathogens.

Dynamic distress calls: volatile info chemicals induce and regulate defense responses during herbivory.

Plants are continuously threatened by a plethora of biotic stresses caused by microbes, pathogens, and pests, which often act as the major constraint in crop productivity. To overcome such attacks, plants have evolved with an array of constitutive and induced defense mechanisms- morphological, biochemical, and molecular. Volatile organic compounds (VOCs) are a class of specialized metabolites that are naturally emitted by plants and play an important role in plant communication and signaling. During herbivory and mechanical damage, plants also emit an exclusive blend of volatiles often referred to as herbivore-induced plant volatiles (HIPVs). The composition of this unique aroma bouquet is dependent upon the plant species, developmental stage, environment, and herbivore species. HIPVs emitted from infested and non-infested plant parts can prime plant defense responses by various mechanisms such as redox, systemic and jasmonate signaling, activation of mitogen-activated protein (MAP) kinases, and transcription factors; mediate histone modifications; and can also modulate the interactions with natural enemies via direct and indirect mechanisms. These specific volatile cues mediate allelopathic interactions leading to altered transcription of defense-related genes, viz., proteinase inhibitors, amylase inhibitors in neighboring plants, and enhanced levels of defense-related secondary metabolites like terpenoids and phenolic compounds. These factors act as deterrents to feeding insects, attract parasitoids, and provoke behavioral changes in plants and their neighboring species. This review presents an overview of the plasticity identified in HIPVs and their role as regulators of plant defense in Solanaceous plants. The selective emission of green leaf volatiles (GLVs) including hexanal and its derivatives, terpenes, methyl salicylate, and methyl jasmonate (MeJa) inducing direct and indirect defense responses during an attack from phloem-sucking and leaf-chewing pests is discussed. Furthermore, we also focus on the recent developments in the field of metabolic engineering focused on modulation of the volatile bouquet to improve plant defenses.

Supplementation of the Plant Conditioner ELICE Vakcina® Product with β-Aminobutyric Acid and Salicylic Acid May Lead to Trans-Priming Signaling in Barley (Hordeum vulgare).

Plant immunological memory, priming, is a defense mechanism that can be triggered by external stimuli, leading to the activation of biochemical pathways and preparing plants for disease resistance. Plant conditioners improve yield and crop quality through nutrient efficiency and abiotic stress tolerance, which is enhanced by the addition of resistance- and priming-induced compounds. Based on this hypothesis, this study aimed to investigate plant responses to priming actives of different natures, including salicylic acid and beta-aminobutyric acid, in combination with the plant conditioning agent ELICE Vakcina®. Phytotron experiments and RNA-Seq analyses of differentially expressed genes using the combinations of these three investigated compounds were performed in a barley culture to investigate possible synergistic relationships in the genetic regulatory network. The results indicated a strong regulation of defense responses, which was enhanced by supplemental treatments; however, both synergistic and antagonistic effects were enhanced with one or two components, depending on the supplementation. The overexpressed transcripts were functionally annotated to assess their involvement in jasmonic acid and salicylic acid signaling; however, their determinant genes were highly dependent on the supplemental treatments. Although the effects overlapped, the potential effects of trans-priming the two supplements tested could be largely separated.

Detection of neuronal defensive discharge information transmission and characteristics in periaqueductal gray double-subregions using PtNP/PEDOT:PSS modified microelectrode arrays

Threatened animals respond with appropriate defensive behaviors to survive. It has been accepted that midbrain periaqueductal gray (PAG) plays an essential role in the circuitry system and organizes defensive behavioral responses. However, the role and correlation of different PAG subregions in the expression of different defensive behaviors remain largely unexplored. Here, we designed and manufactured a microelectrode array (MEA) to simultaneously detect the activities of dPAG and vPAG neurons in freely behaving rats. To improve the detection performance of the MEAs, PtNP/PEDOT:PSS nanocomposites were modified onto the MEAs. Subsequently, the predator odor was used to induce the rat’s innate fear, and the changes and information transmission in neuronal activities were detected in the dPAG and vPAG. Our results showed that the dPAG and vPAG participated in innate fear, but the activation degree was distinct in different defense behaviors. During flight, neuronal responses were stronger and earlier in the dPAG than the vPAG, while vPAG neurons responded more strongly during freezing. By applying high-performance MEA, it was revealed that neural information spread from the activated dPAG to the weakly activated vPAG. Our research also revealed that dPAG and vPAG neurons exhibited different defensive discharge characteristics, and dPAG neurons participated in the regulation of defense responses with burst-firing patterns. The slow activation and continuous firing of vPAG neurons cooresponded with the regulation of long-term freezing responses. The results demonstrated the important role of PAG neuronal activities in controlling different aspects of defensive behaviors and provided novel insights for investigating defense from the electrophysiological perspective.

Identification of Vitis vinifera MYB transcription factors and their response against grapevine berry inner necrosis virus

BackgroundThe myeloblastosis (MYB) superfamily is the largest transcription factor family in plants that play diverse roles during stress responses. However, the biotic stress-responsive MYB transcription factors of the grapevine have not been systematically studied. In China, grapevine berries are often infected with the grapevine berry inner necrosis virus (GINV), which eventually reduces the nutritional quality and commodity value.ResultsThe present study identified and characterized 265 VvMYB or VvMYB-related genes of the “Crimson seedless” grapevine. Based on DNA-binding domain analysis, these VvMYB proteins were classified into four subfamilies, including MYB-related, 2R-MYB, 3R-MYB, and 4R-MYB. Phylogenetic analysis divided the MYB transcription factors into 26 subgroups. Overexpression of VvMYB58 suppressed GINV abundance in the grapevine. Further qPCR indicated that among 41 randomly selected VvMYB genes, 12 were induced during GINV infection, while 28 were downregulated. These findings suggest that VvMYB genes actively regulate defense response in the grapevine.ConclusionA deeper understanding of the MYB TFs engaged in GINV defense response will help devise better management strategies. The present study also provides a foundation for further research on the functions of the MYB transcription factors.

Transcriptomic and metabolic studies on the role of inorganic and organic iodine compounds in lettuce plants

Iodine (I) is considered a beneficial element or even micronutrient for plants. The aim of this study was to determine the molecular and physiological processes of uptake, transport, and metabolism of I applied to lettuce plants. KIO3, KIO3 + salicylic acid, 5-iodosalicylic acid and 3,5-diiodosalicylic acid were applied. RNA-sequencing was executed using 18 cDNA libraries constructed separately for leaves and roots from KIO3, SA and control plants. De novo transcriptome assembly generated 1937.76 million sequence reads resulting in 27,163 transcripts with N50 of 1638 bp. 329 differentially expressed genes (DEGs) in roots were detected after application of KIO3, out of which 252 genes were up-regulated, and 77 were down-regulated. In leaves, 9 genes revealed differential expression pattern. DEGs analysis indicated its involvement in such metabolic pathways and processes as: chloride transmembrane transport, phenylpropanoid metabolism, positive regulation of defense response and leaf abscission, and also ubiquinone and other terpenoid-quinone biosynthesis, protein processing in endoplasmic reticulum, circadian rhythm including flowering induction as well as a putative PDTHA (i.e. Plant Derived Thyroid Hormone Analogs) metabolic pathway. qRT-PCR of selected genes suggested their participation in the transport and metabolism of iodine compounds, biosynthesis of primary and secondary metabolites, PDTHA pathway and flowering induction.

Chemoproteomics Reveals the Pan-HER Kinase Inhibitor Neratinib To Target an Arabidopsis Epoxide Hydrolase Related to Phytohormone Signaling.

Plant phytohormone pathways are regulated by an intricate network of signaling components and modulators, many of which still remain unknown. Here, we report a forward chemical genetics approach for the identification of functional SA agonists in Arabidopsis thaliana that revealed Neratinib (Ner), a covalent pan-HER kinase inhibitor drug in humans, as a modulator of SA signaling. Instead of a protein kinase, chemoproteomics unveiled that Ner covalently modifies a surface-exposed cysteine residue of Arabidopsis epoxide hydrolase isoform 7 (AtEH7), thereby triggering its allosteric inhibition. Physiologically, the Ner application induces jasmonate metabolism in an AtEH7-dependent manner as an early response. In addition, it modulates PATHOGENESIS RELATED 1 (PR1) expression as a hallmark of SA signaling activation as a later effect. AtEH7, however, is not the exclusive target for this physiological readout induced by Ner. Although the underlying molecular mechanisms of AtEH7-dependent modulation of jasmonate signaling and Ner-induced PR1-dependent activation of SA signaling and thus defense response regulation remain unknown, our present work illustrates the powerful combination of forward chemical genetics and chemical proteomics for identifying novel phytohormone signaling modulatory factors. It also suggests that marginally explored metabolic enzymes such as epoxide hydrolases may have further physiological roles in modulating signaling.