Defense Genes Research Articles

Casein Glycomacropeptide Regulates Gene Expression in Intestinal Epithelial Cells: Effect of Simulated Gastrointestinal Digestion and Peptide Microencapsulation.

κ-Casein glycomacropeptide (GMP) exerts anti-inflammatory and immune modulatory effects. A bovine GMP concentrate and its in vitro digestion product were obtained. GMP was also microencapsulated with phycocolloids and further digested. These products were tested in three-dimensional (3D) and open monolayer two-dimensional (2D) mouse jejunal organoids. Almost no effect was observed on the 2D organoids. In 3D organoids, GMP induced intestinal proliferation (Axin2, Pcna) and differentiation (Vil1, Alpl) genes together with Muc3, antibacterial genes (Lyz1, Pla2g2a), and Cxcl1. GMP also induced interferon I defense genes (Ifnb1, Ifr3, Oas2, Oas3, Rnasel) under basal conditions and in TNF-stimulated organoids. In vitro digestion abrogated the effects of GMP and induced new genes (Lgr5, Olfm4, and Lct). In TNF-stimulated organoids, digested GMP repressed multiple genes. Encapsulation largely preserved the GMP effects. In conclusion, GMP showed differential effects in 3D and 2D organoids. The effects of digestion peptides were also different, suggesting distinct potential as functional foods.

Physiological and molecular mechanisms of exogenous salicylic acid in enhancing salt tolerance in tobacco seedlings by regulating antioxidant defence system and gene expression

Physiological and molecular mechanisms of exogenous salicylic acid in enhancing salt tolerance in tobacco seedlings by regulating antioxidant defence system and gene expression

SlABCG9 Functioning as a Jasmonic Acid Transporter Influences Tomato Resistance to Botrytis cinerea.

Jasmonic acid (JA) is crucial for plant stress responses, which rely on intercellular jasmonate transport. However, JA transporters have not been fully identified, especially in tomato (Solanum lycopersicum L.). This study reveals that plasma-membrane-localized protein SlABCG9 in tomato regulates fruit resistance to Botrytis cinerea. Transcriptomic analysis indicated that the SlABCG9 expression was significantly upregulated after B. cinerea infection. Assays using Xenopus oocytes, yeast cell sensitivity, and JA-inhibited primary root growth confirmed that SlABCG9 functions as a JA influx transporter. The knockout mutant lines of SlABCG9 showed decreased JA contents, suppressed defense gene PDF1.2's expression, reduced antioxidant enzyme activity, and severe disease symptoms compared to wild-type controls. Our findings provide new knowledge for understanding how the JA transporter and signaling pathway are involved in the biotic stress responses and improve the resistant ability against pathogen infections.

In silico characterisation of the avocado WAK/WAKL gene family with a focus on genes involved in defence against Phytophthora cinnamomi

The avocado industry faces a significant threat from the hemibiotrophic oomycete pathogen Phytophthora cinnamomi. A variably expressed defence gene during an avocado infection trial was a Wall-associated kinase (WAK). WAK and WAK-Like (WAKL) proteins are known to bind to fragmented pectin (oligogalacturonides) produced during pathogen penetration, thereby activating downstream defence-related pathways. To better understand the P. cinnamomi-avocado defence interaction, this gene family was assessed using in silico methods. In this study, previously generated RNA-sequencing data were used to associate genes with the defence response, followed by promoter- and phylogenetic analysis of these genes/proteins. The predicted proteins from these genes were modelled with AlphaFold2, and structural similarity across different rootstocks, as well as their binding affinity for oligogalacturonides, were assessed. The analysis identified 14 Persea americana (Pa)WAKs and 62 PaWAKLs across the West-Indian (pure accession reference), Dusa®, Leola™ and R0.12 avocado rootstock genomes. These genes showed distribution across the West-Indian genome’s chromosomes, with MCScanX analyses predicting tandem duplications. PaWAK/WAKL expression profiles were compared, implicating five PaWAK/WAKLs in defence. Phylogenetic and promoter analyses were conducted to predict associated defence-related pathways, focusing on stress and phytohormone-responsive pathways. Structural differences and varying oligogalacturonide binding affinities of PaWAK/WAKLs were predicted across rootstocks. These defence-related genes could be incorporated into a molecular screening tool to improve the development of resistant avocado rootstocks.

A phytocytokine and its derived peptides in the frass of an insect elicit rice defenses.

Upon recognizing elicitors derived from herbivores, many plants activate specific defenses. Most of the elicitors identified thus far are from the oral secretions and egg-laying fluids of herbivores; in contrast, herbivore fecal excreta have been sparsely studied in this context. In this study, we identified elicitors in the frass of the striped stem borer (SSB; Chilo suppressalis) larvae using a combination of molecular and chemical analyses, bioactivity tests and insect performance bioassays. Treating rice plants with SSB frass or a solution composed of SSB frass and buffer elicited mitogen-activated protein kinase (MPK) cascades and the jasmonic acid (JA)-signaling pathway. Moreover, the treatment induced both the expression of defense-related genes and the production of defensive compounds, and enhanced the resistance of rice plants to SSB. Heating SSB frass solution did not affect its induction activity, but eliminating proteins and peptides from the solution by adding proteinase K impaired its activity. Additional chemical analyses and bioassays revealed that the rice phytocytokine, immune response peptide 1(IRP1), together with some of its derived peptides in SSB frass, induced the MPK cascades, JA biosynthesis, the expression of defense genes and the production of defensive compounds in rice. These results reveal an important role for the plant-derived fecal peptide phytocytokine IRP1 and some of its derived peptides in inducing defenses in rice against SSB.

Expression profiles of NOD1 and NOD2 and pathological changes in gills during Flavobacterium columnare infection in yellow catfish, Tachysurus fulvidraco.

NOD-like receptors are significant contributors to the immune response of fish against different types of pathogen invasion. NOD1 and NOD2 genes of yellow catfish (Tachysurus fulvidraco) were identified and characterized in this study. Yellow catfish NOD1 and NOD2 have open reading frames (ORFs) of 2841 and 2949 bp, encoding 946 and 982 amino acids, respectively. Both NOD1 and NOD2 are intracellular proteins lacking transmembrane regions and signal peptides. Sequence homology analysis revealed that the protein sequences of NOD1 and NOD2 of yellow catfish are highly similar to those of channel catfish. Both NOD1 and NOD2 showed high expression in the head kidney, and spleen. Following challenge with Flavobacterium columnare, NOD1 expression obviously increased in the liver, spleen, midgut, and hindgut, whereas NOD2 clearly increased in head kidney, and gut. Microscopic observation of gill tissues revealed evident epithelial hyperplasia in the secondary gill filaments at 3 and 6 hpi, with a notable decrease in the aspect ratio in comparison with the control group, followed by a return to baseline levels. These findings indicate a potential involvement of NOD1 and NOD2 genes in defense against F. columnare invasion. The findings of this study contribute valuable insights into NOD1 and NOD2's functions in the innate immune response of yellow catfish and other fish species to bacterial infection.

Integrons are anti-phage defence libraries in Vibrio parahaemolyticus.

Bacterial genomes have regions known as defence islands that encode diverse systems to protect against phage infection. Although genetic elements that capture and store gene cassettes in Vibrio species, called integrons, are known to play an important role in bacterial adaptation, a role in phage defence had not been defined. Here we combine bioinformatic and molecular techniques to show that the chromosomal integron of Vibrio parahaemolyticus is a hotspot for anti-phage defence genes. Using bioinformatics, we discovered that previously characterized defences localize to integrons. Intrigued by this discovery, we cloned 57 integron gene cassettes and identified 9 previously unrecognized systems that mediate defence. Our work reveals that integrons are an important reservoir of defence systems in V. parahaemolyticus. As integrons are of ancient origin and are widely distributed among Proteobacteria, these results provide an approach for the discovery of anti-phage defence systems across a broad range of bacteria.

Abstract P018: Mapping cellular and microenvironmental determinants of persister populations in pancreatic cancer following neoadjuvant chemoradiation

Abstract Introduction: The molecular pathways involved in the response to radiation therapy (RT) in pancreatic ductal adenocarcinoma (PDAC) remain poorly understood. Attempts to combine RT with immunotherapies in PDAC have yielded inconsistent outcomes, highlighting a critical gap in our understanding of immune dynamics and mechanisms influencing RT response. Our study aims to uncover molecular pathways and cellular subtypes associated with radioresponse. To do so, we developed a novel cell-cell interaction platform, "SpaCCI", to map ligand-receptor (LR) interactions, essential for understanding cellular communication within the TME and its contribution to therapeutic resistance. Methods: Single-cell RNA sequencing (scRNA-seq) was performed on 16 matched pre- and post-treatment PDAC biopsies from a Phase I/II dose-escalation clinical trial of stereotactic body radiation therapy. Additionally, spatial transcriptomics (ST) was conducted on resected PDAC (20 treated with neoadjuvant chemoradiation, 8 untreated). We integrated scRNA-seq and ST datasets using cell type decomposition and developed SpaCCI to enhance LR interaction detection in tissues with complex cell mixtures. Results: ScRNA-seq identified five molecular subpopulations of cancer cells associated to RT response, with PDAC_3 enriched post-RT and marked by genes involved in lipid metabolism and ferroptosis defense. Post-RT depleted subpopulations, such as PDAC_0 and PDAC_prolif, saw upregulation of pathways related to rapid proliferation and oxidative phosphorylation. In a murine model, PDAC_3 was similarly enriched in post-RT tumors, with persister cell lines from these tumors showing overexpression of ferroptosis defense genes and resistance to ferroptosis inducers including Erastin and RSL3. ST analysis also revealed spatial immune changes post-RT, with increased cytotoxic and effector memory T cells balanced by regulatory T cells and M2-like macrophages, indicating immune escape. NK and memory B cells correlated with improved survival post-RT, while plasma IgG cells localized outside the tumor bed, suggesting compartmentalized immune responses. Using SpaCCI, we observed differential enrichment of ligand-receptor interactions in RT-treated tumors, particularly among lipid-associated tumor macrophages, cancer cells, myofibroblast-like cancer-associated fibroblasts, and endothelial cells. Persister PDAC_3 subpopulations showed enriched LR SEMA3 signaling with CAFs, myeloid cells, and endothelial cells consistent with axon guidance pathways. Conclusions: This study presents a molecular and cellular atlas of PDAC response to RT, revealing persister cells populations with adaptations in lipid metabolism and ferroptosis defense that could be targeted to enhance RT efficacy. ST highlighted complex immune dynamics within the TME demonstrating a balance between inflammatory and immunosuppressive populations. Our findings provide a foundation for combinatorial therapeutic strategies and suggest that axon guidance pathways may also play an important role in the response to RT in PDAC. Citation Format: Vincent Bernard, Li-Ting Ku, Tianyu Wang, Kimal Rajapakshe, Dadi Jiang, Galia Jacobson, Jimin Min, Ching-Wei Tzeng, Manoop S. Bhutani, Paola A. Guerrero, Ethan B. Ludmir, Albert C. Koong, Cullen M. Taniguchi, Anirban Maitra, Ziyi Li, Eugene J. Koay.Mapping cellular and microenvironmental determinants of persister populations in pancreatic cancer following neoadjuvant chemoradiation.[abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Targeted Therapies in Combination with Radiotherapy; 2025 Jan 26-29; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(2_Suppl):Abstract nr P018

Abscisic Acid Can Play a Dual Role in the Triticum aestivum–Stagonospora nodorum Pathosystem

Abscisic acid (ABA) is not only important for plant responses to abiotic stresses, but also plays a key and multifaceted role in plant immunity. In this work, we analyzed the role of ABA in the development of resistance/susceptibility in the wheat (Triticum aestivum L.)–Stagonospora nodorum Berk. pathosystem, which includes the recognition of the necrotic effectors (NEs) of a pathogen by the corresponding wheat susceptibility genes. We studied the interaction of the S. nodorum SnB isolate, which produces two NEs, SnToxA and SnTox3, with three wheat genotypes having different combinations of the corresponding host susceptibility genes (Tsn1 and Snn3-B1). The results of this work on the gene expression and redox status of resistant and sensitive wheat genotypes treated with ABA show that ABA signaling is directed at inducing the resistance of wheat plants to S. nodorum SnB isolate through the activation of the early post-invasive defense genes TaERD15 and TaABI5. The induction of the expression of these genes leads to reactive oxygen species (ROS) accumulation during the early stage of infection, with the subsequent limitation of the pathogen’s growth. In the presence of a compatible interaction of SnTox3–Snn3-B1, ABA signaling is suppressed. On the contrary, in the presence of a compatible interaction of SnToxA–Tsn1, ABA signaling is activated, but the activity of the early post-invasive defense genes TaERD15 and TaABI5 is inhibited, and the expression of the NAC (NAM, ATAF1/2, and CUC2) transcription factor (TF) family genes TaNAC29 and TaNAC21/22 is induced. The TF genes TaNAC29 and TaNAC21/22 in the presence of SnToxA induce the development of the susceptibility of wheat plants to S. nodorum SnB, associated with a decrease in the oxidative burst during the early stage of infection. Thus, our study provides new data on the role of the NEs SnTox3 and SnToxA in manipulating ABA signaling in the development of the susceptibility of wheat to S. nodorum. Deepening our knowledge in this area will be instrumental for developing new strategies for breeding programs and will contribute to the development of environmentally friendly sustainable agriculture.

Toll/interleukin-1 receptor-only genes contribute to immune responses in maize.

Proteins with Toll/interleukin-1 receptor (TIR) domains are widely distributed in both prokaryotes and eukaryotes, serving as essential components of immune signaling. Although monocots lack the major TIR-nucleotide-binding (NB)-leucine-rich repeat (LRR)-type (TNL) immune receptors, they possess a small number of TIR-only proteins, the function of which remains largely unknown. In the monocot maize (Zea mays), there are three conserved TIR-only genes in the reference genome, namely ZmTIR1 to ZmTIR3. A genome-wide scan for TIR genes and comparative analysis revealed that these genes exhibit low sequence diversity and do not show copy number variation among 26 diverse inbred lines. ZmTIR1 and ZmTIR3, but not ZmTIR2, specifically trigger cell death and defense gene expression when overexpressed in Nicotiana benthamiana leaves. These responses depend on the critical glutamic acid and cysteine residues predicted to be essential for TIR-mediated NADase and 2',3'-cAMP/cGMP synthetase activity, respectively, as well as the key TIR downstream regulator Enhanced Disease Susceptibility 1 (EDS1). Overexpression of ZmTIR3 in N. benthamiana produces signaling molecules, including 2'cADPR, 2',3'-cAMP and 2',3'-cGMP, a process that requires the enzymatic glutamic acid and cysteine residues of ZmTIR3. ZmTIR expression in maize is barely detectable under normal conditions, but is substantially induced by different pathogens. Importantly, the maize Zmtir3 knockout mutant exhibits enhanced susceptibility to the fungal pathogen Cochliobolus heterostrophus, highlighting the role of ZmTIR3 in maize immunity. Overall, our results unveil the function of the maize ZmTIRs. We propose that the pathogen-inducible ZmTIRs play an important role in maize immunity, likely through their enzymatic activity and via EDS1-mediated signaling.

Francisella tularensis universal stress protein contributes to persistence during growth arrest and paraquat-induced superoxide stress.

Francisella tularensis is classified as a Tier 1 select agent due to the low infectious dose, ease of transmission, and potential use as a bioweapon. To better understand the stress defense mechanisms that contribute to the ability of this highly virulent pathogen to persist, we evaluated the conserved F. tularensis universal stress protein (Usp). We show that F. tularensis Usp is unusually stable and remains abundant, regardless of the stress conditions tested, differing from other bacterial Usp homologs. We also determined that F. tularensis Usp enhances the expression of several critical antioxidant defense genes and increases survival during paraquat exposure and growth arrest. Determining the factors that promote F. tularensis persistence in the environment is needed to prevent tularemia transmission.

Efficacy of biocontrol agents against damping-off and Sclerotinia stem rot diseases and their role in eliciting defense in chickpea plants

BackgroundChickpea (Cicer arietinum L.) is the third most important pulse crop grown worldwide. Sclerotinia sclerotiorum causes damping-off and stem rot diseases, leading to significant economic losses in chickpea crop yield. Biological control has proved to be an effective alternative for managing plant diseases.ResultsThese pathogenic fungi were isolated from different governorates in Egypt and differed in terms of their pathogenicity on Giza 3 cv.-chickpea plants in vivo. S. sclerotiorum Sakha-S1 with accession No. (PQ558663) was the most aggressive isolate. Trichoderma atroviride was the most effective fungal bioagent in vitro since recorded the highest S. sclerotiorum growth decrease, followed by T. hamatum and T. harzianum; meanwhile, Serratia sp. was the least effective isolate. In greenhouse conditions, Topsin M-70® emerged as the most successful treatment for reducing disease prevalence. Combinations of microbial bioagents specifically all four (T. atroviride, Pseudomonas fluorescens, Bacillus polymyxa, and Serratia sp.) and a combination of three (P. fluorescens, B. polymyxa, and Serratia sp.) followed in effectiveness. Serratia sp. applied alone proved to be the least effective treatment. The same results were obtained in a two-year field study (2020–2021 and 2021–2022) and assessed the impact of various treatments on chickpea disease, growth, and yield components. Interestingly, all the microbial bioagents substantially enhanced chickpea growth parameters, including plant height, number of branches per plant, number of capsules per plant, number of seeds per plant, seed weight per plant, average weight of 100 seeds, and overall chickpea yield. The role of these microbial bioagents in the defense of oxidation enzymes (Peroxidase, polyphenol oxidase, and catalase) associated with defense-related genes (ABR18, PRP, and PR-4) which shown notable variations in gene expression levels of defense-related genes due to treated with various microbial bioagents after 14 days from application. All three genes were up-regulated in combinations including (P. fluorescens + Serratia sp.), (T. atroviride + P. fluorescens), and (T. atroviride + Serratia sp.), demonstrating a collaborative impact on defense gene expression.ConclusionThe study investigated the effectiveness of microbial bioagents against chickpea stem rot disease, their role in the defense of oxidation enzymes and defense-related genes, and their impact on growth and yield components. It will focus on producing commercial biofungicides to minimize the use of fungicides.

Differential activation of defense responses in cucumbers by adapted versus non-adapted lineages of the cotton-melon aphid.

The cotton-melon aphid, Aphis gossypii Glover, is a polyphagous pest damaging plants across over 100 families. It has multiple host-specialized lineages, including one colonizing Malvaceae (MA) and one colonizing Cucurbitaceae (CU). The mechanisms underlying these host relationships remain unknown. Here, we compared defensive compounds, gene expressions and aphid susceptibility of cucumbers (Cucumis sativus L.) that were infested with both lineages for up to 14 days. Total jasmonic acid (JA) remained constant in CU-infested cucumbers while increased to a maximum of 19.11 folds at 1 dpi (days post infestation) in MA-infested cucumbers. Total salicylic acid (SA) increased to a maximum of 4.42 folds at 7 dpi in MA-infested cucumbers while increased to a maximum of 2.83 folds at 14 dpi in CU-infested cucumbers. Reactive oxygen species were constantly higher in MA-infested cucumbers than CU-infested cucumbers at each time point. Genes involved in defense signaling, for example, MAPKs, PR-1s, and WRKY, and genes involved in JA and SA biosynthesis, were largely up-regulated in MA-infested cucumbers compared with CU-infested ones. Both lineages exhibited more stylet probing, less phloem ingestion, higher mortality, and less reproduction on MA-infested cucumbers compared with CU-infested ones. MA lineage aphids elicited stronger defenses in cucumbers than the CU lineage aphids. A lack of salivary effectors specific to cucumbers most likely prevents MA lineage aphids from using cucumbers. Identifying lineage-specific elicitors or effectors is therefore expected to unveil the molecular mechanisms of host specificity of this aphid. © 2025 Society of Chemical Industry.

OAS1: A Protective Mechanism for Alzheimer's Disease? An Exploration of Data and Possible Mechanisms.

The immune system and neuroinflammation are now well established in the aetiology of neurodegeneration. Previous studies of transcriptomic and gene association studies have highlighted the potential of the 2'-5' oligoadenylate synthetase 1 (OAS1) to play a role in Alzheimer's disease. OAS1 is a viral response gene, interferon-induced, dsRNA activated enzyme, which binds RNase L to degrade dsRNA, and has been associated with COVID-19 response. This study explores whether a viral defence gene could play a vital role in neurodegeneration pathology. The genotyping of five SNPs across the OAS1 locus was conducted in the Brains for Dementia Research (BDR) Cohort for association with AD. RNA-sequencing data were explored for differences in OAS1 gene expression between phenotypes and genotypes. Finally, levels of dsRNA were measured in control cell lines, prior to and after exposure to amyloid oligomers and in cells harbouring a dementia-relevant mutation. No association of any of the OAS1 SNPs investigated were associated with the AD phenotype in the BDR cohort. However, gene expression data supported the previous observation that the minor allele haplotype was associated with higher levels of the OAS1 gene expression and the presence of an alternative transcript. Further to this, the presence of endogenous dsRNA was found to increase with exposure to amyloid oligomers and in the cell line with a dementia-relevant mutation. The data presented here suggest further exploration of the OAS1 gene in relation to dementia is warranted. Investigations of whether carriers of the protective OAS1 haplotype lower dsRNA presence and in turn lower inflammation and cell death are required to support the role of the gene as a moderator of neurodegeneration.

Tomato B-cell lymphoma2 (Bcl2)-associated athanogene 5 (SlBAG5) contributes negatively to immunity against necrotrophic fungus Botrytis cinerea through interacting with SlBAP1 and modulating catalase activity.

The evolutionarily conserved and multifunctional B-cell lymphoma2 (Bcl2)-associated athanogene proteins (BAGs), serving as co-chaperone regulators, play a pivotal role in orchestrating plant stress responses. In this study, the possible involvement of tomato SlBAG genes in resistance to Botrytis cinerea was examined. The SlBAG genes respond with different expression change patterns to B. cinerea and defense signaling hormones. SlBAG proteins are individually differentially localized to the nucleus, mitochondria, cytoplasm, endoplasmic reticulum (ER), or vacuole. Silencing of SlBAG5 enhanced immunity to B. cinerea, while overexpression weakened it, affecting Botrytis-induced JA/ET defense gene expression and JA levels. Chitin-induced ROS burst and expression of PTI marker genes SlPTI5 and SlLRR22 were strengthened in SlBAG5-silenced plants but were weakened in SlBAG5-overexpressing plants (SlBAG5-OE) plants. SlBAG5 interacts with BON1 ASSOCIATED PROTEIN 1 (SlBAP1) through its BAG domain, and the stability of SlBAP1 depends on the presence of SlBAG5. Silencing of SlBAP1 conferred increased resistance to B. cinerea through increased expression of JA/ET signaling and defense genes. SlBAP1 functions by recruiting and boosting SlCAT3 activity to remove H2O2. The findings suggest that SlBAG5 suppresses tomato immunity to B. cinerea by stabilizing SlBAP1, which modulates ROS scavenging and acts as a negative regulator of immunity.

RNAi-mediated knockdown of HcCAT2 depresses the adaptive capacity of Hyphantria cunea larvae to cytisine and coumarin.

The diversity of host plants is an important reason for the global spread of Hyphantria cunea. However, no studies have explored the role of the antioxidant defense system with catalase (CAT) as the core at the molecular level in the adaptation of the H. cunea to host plant secondary metabolites. Herein, the purpose is to explore how HcCAT2, highly expressed in cytisine- or coumarin-treated H. cunea larvae, mediates the adaptation of H. cunea to cytisine and coumarin, and to develop nucleic acid pesticides targeting HcCAT2. Findings revealed that H. cunea larvae treated with dsHcCAT2 alongside cytisine or coumarin exhibited significantly reduced body weight, survival rate, and expression levels of growth-related genes, energy metabolism genes, and oxidative damage regulatory genes compared to treated with cytisine or coumarin alone. HcCAT2 overexpression enhanced cell viability, lowered apoptosis rates, Ca2+ concentrations, ROS levels, and MPTP opening, and increased mitochondrial membrane potential in cytisine or coumarin-treated SF9 cells. Encapsulation of dsHcCAT2 in chitosan (CS) improved stability and gene silencing efficacy. CS-dsHcCAT2 treatment did not significantly affect SF9 cell, Lymantria dispar larvae, and Arma chinensis nymphs. However, H. cunea larvae treated with CS-dsHcCAT2 combined with cytisine or coumarin showed significantly reduced body weight and survival compared to those receiving secondary metabolites alone. Therefore, HcCAT2 is a critical antioxidant defense gene for adaptation of H. cunea larvae to cytisine and coumarin stress, with the ability of maintaining energy metabolism homeostasis and antioxidant defense level. The constructed CS-dsHcCAT2 can be developed as a synergistic agent for plant-derived pesticides.

A small RNA effector conserved in herbivore insects suppresses host plant defense by cross-kingdom gene silencing.

Herbivore insects deploy salivary effectors to manipulate the defense of their host plants. However, it remains unclear whether small RNAs from insects can function as effectors in regulating plant-insect interactions. Here, we report that a microRNA (miR29-b) found in the saliva of the phloem-feeding whitefly (Bemisia tabaci) can transfer into the host plant phloem during feeding and fine-tune the defense response of tobacco (Nicotiana tabacum) plants. We show that the salivary gland-enriched BtmiR29-b is produced by BtDicer 1 and released into tobacco cells via salivary exosomes. Once inside the plant cells, BtmiR29-b hijacks tobacco Argonaute 1 to silence the defense gene Bcl-2-associated athanogene 4 (NtBAG4). In tobacco, NtBAG4 acts as the positive regulator of phytohormones salicylic acid(SA) and jasmonic acid(JA), enhancing plant defense against whitefly attacks. Interestingly, we also found that miR29-b acts as a salivary effector in another Hemipteran insect, the aphid Myzus persicae, which inhibits tobacco resistance by degrading NtBAG4. Moreover, miR29-b is highly conserved in Hemiptera and across other insect orders such as Coleoptera, Hymenoptera, Orthoptera, and Blattaria. Computational analysis suggests that miR29-b may also target the evolutionarily conserved BAG4 gene in other plant species. We further provide evidence showing BtmiR29-b-mediated BAG4 cleavage and defense suppression in tomato (Solanum lycopersicum). Taken together, our work reveals that a conserved miR29-b effector from insects fine-tunes plant SA- and JA-mediated defense by cross-kingdom silencing of the host plant BAG4 gene, providing new insight into the defense and counter-defense mechanisms between herbivores and their host plants.

Investigation of the Effects of Silymarin on Ovarian Ischemia Reperfusion via Nrf-2/HO-1/NQO1, Ki-67 and Wnt Signaling Pathways.

Ovarian ischemia is a pathological condition that usually occurs due to ovarian torsion, resulting in the interruption of blood supply to the ovaries and oxygen deficiency. Silymarin (SLM) is a flavonoid complex of plant origin with pharmacological properties such as antioxidant, anti-inflammatory, and antiapoptotic effects. In this study, we investigated the effects of SLM through different pathways in rats subjected to experimental ovarian ischemia/reperfusion (I/R). Female Wistar rats were divided into five groups: Control, SLM (50 mg/kg), I/R, I/R + SLM25 (25 mg/kg), and I/R + SLM50 (50 mg/kg). SLM was given orally for 7 days, followed by ischemia (2 h) and reperfusion (2 h) on day 8. Biochemical (MDA, GSH, SOD, CAT, GPx) and histological (H&E, Ki-67 IHC) analyses were performed. Also, molecular (qRT-PCR) analyses were performed to evaluate oxidative stress, inflammation, apoptosis, and Wnt signaling. I/R increased MDA and NO levels in ovarian tissue while decreasing SOD, CAT, GPx, and GSH. Antioxidant defense genes (Nrf-2, HO-1, NQO1) were suppressed, and inflammation markers (NF-ĸB, IL-1β, TNF-α) along with apoptotic markers (Bax, Caspase-3) were elevated, while Bcl-2 decreased. The Wnt signaling pathway was inhibited, particularly at Wnt-3A, LRP5, Dvl-2, and Cyclin-1, reducing Ki-67 protein levels and IHC positivity. Silymarin has shown a therapeutic effect on ovarian ischemia reperfusion injury with its antioxidant, antiapoptotic and anti-inflammatory effects and cell cycle regulatory activity.

Rhizobacterial-induced defense genes and their role in tomato systemic resistance against wilt disease

Rhizobacterial-induced defense genes and their role in tomato systemic resistance against wilt disease

Histone Modification-Dependent Transcriptional Regulation of Defence Genes in Early Response of Arabidopsis to Spodoptera litura Attack.

Histone modification is a cellular process for transcriptional regulation. In herbivore-damaged plants, activation of genes involved in defence responses is required for antiherbivore properties, but little is known about how the chromatin remodelling system is involved. In Arabidopsis (Arabidopsis thaliana) plants responding to Spodoptera litura larvae, HAC1 and HDA6, a histone acetyltransferase and a histone deacetylase, respectively, were found here to be involved in histone H3 (Lys9; H3K9) acetylation/deacetylation at the promoter region of the plant defensin gene PDF1.2 and the gene body of ethylene response factor 13 (ERF13) as early as 2 h after the onset of herbivore attack. The H3K9 acetylation was responsible for the robust upregulation of PDF1.2 later, at 24 h, and ERF13 even earlier, at 1 h. TOPLESS (TPL) and TOPLESS-related (TPR) corepressors interacted with HDA6 to deacetylate H3K9 at PDF1.2 and ERF13, while negatively regulating the expression of PDF1.2 but not ERF13. Furthermore, TPL also interacted with ERF13, resulting in ERF13-mediated regulation of PDF1.2. Taken together, these data suggest a model of promoter-restricted, TPL/TPR-directed histone deacetylation and transcription factor repression in healthyArabidopsis plants for the feedback regulation of the antiherbivore response.