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PubMed2025

Foliar disease resistance phenomics of fungal pathogens: image-based approaches for mapping quantitative resistance in cereal germplasm.

Host plant resistance is the most effective and environmentally sustainable means of reducing yield losses caused by fungal foliar pathogens of cereal species. Cereal genebank collections hold diverse pools of potentially underutilized disease resistance alleles, and cereal genomic resources are well advanced due to large-scale sequencing and genotyping efforts. Genome-Wide Association Studies (GWAS) have emerged as the predominant association genetics technique to initially discover novel disease resistance loci or alleles in these diverse collections. Traditional disease resistance phenotyping methods are reliant on visual estimation of disease symptom severity and have successfully supported genetic mapping studies either via GWAS or QTL mapping in biparental populations facilitating both marker development and gene cloning efforts. Due to foliar pathogens having a high capacity to evolve, there is a need to pyramid disease resistance genes with diverse mechanisms for durable control. Resistance expressed as a quantitative trait, known as quantitative resistance (QR), is hypothesized to be more durable, unlike major R-gene resistance that is race-specific and can be vulnerable to breaking down without gene stewardship. However, assessing QR visually is challenging, particularly when complicated by complex genotype × environment (G × E) effects in the field. High-throughput image-based phenotyping provides accurate and unbiased data that can support foliar disease resistance screening efforts of genebank collections using GWAS. In this review, we discuss image-based disease phenotyping based on macroscopic (visible symptoms) and microscopic features during the host-pathogen interaction. Quantitative image analysis approaches using conventional and artificial intelligence (AI) algorithms are also discussed.

Disease Resistance↗
PubMed2026

A Leucine-Rich Repeat Receptor-Like Protein Associated with a QTL for Septoria Stem Canker in Populus trichocarpa × Populus deltoides Hybrid Poplar.

The fungal plant pathogen Sphaerulina musiva (Ascomycota) causes Septoria stem canker, the most economically damaging disease of Populus plantations in North America, yet the genetic determinants of host resistance remain uncharacterized in hybrid poplar. Using an inoculation experiment with the 52-124 pseudo-backcross family of Populus trichocarpa × Populus deltoides (TD × D) hybrid poplar, a single significant QTL was identified on Chromosome 16 (LOD = 4.93) associated with both stem canker count and disease severity score. Transcriptomic analysis of two resistant and two susceptible genotypes across a 72-hour infection time course identified a single differentially expressed gene within the QTL candidate gene window: Podel.16G125900, a putative leucine-rich repeat receptor-like protein (LRR-RLP) with homology to receptor-like protein 33 in Arabidopsis thaliana. Podel.16G125900 is located 3001 bp (0.019 cM) upstream of the QTL peak and showed a strong infection-induced upregulation in susceptible genotype 852 (log2 fold-change = 20.47) and higher baseline expression in resistant genotypes relative to susceptible genotypes across all infection time points, consistent with a resistance mechanism in which expression level contributes to the degree of resistance conferred. Two P. trichocarpa homologs were not differentially expressed and differ substantially in sequence content, suggesting the resistance function is specific to the resistant P. deltoides lineage. These findings identify Podel.16G125900 as a strong candidate gene underlying quantitative resistance mechanisms modulating Septoria stem canker resistance in the 52-124 family of TD × D hybrid poplar and provide a target for future functional validation and marker-assisted resistance breeding.

Disease Resistance↗
PubMed2026

Tobamoviruses: Advances in Molecular Biology, Host Interactions and Integrated Disease Management.

Tobamoviruses (viruses in the genus Tobamovirus, family Virgaviridae) lead to major yield losses in economically important crops around the world. In this review, we go beyond the canonical gene expression framework by integrating recent discoveries of reverse open reading frames (rORFs) on the negative-strand RNA. These rORFs have only been experimentally validated in cucumber green mottle mosaic virus (CGMMV), with predicted sequence-conserved homologs across a subset of the genus, including TMV, ToBRFV, and PMMoV. However, they are not universally present in all tobamoviruses. We systematically dissect the infection cycle-from disassembly and replication to cell-to-cell and systemic movement-with an emphasis on the host factors hijacked at each stage. We synthesize current understanding of plant antiviral immunity, focusing on RNA silencing and NLR receptor-mediated resistance as two pillars of defense, along with the transcription factors and microRNAs that orchestrate these responses. We critically evaluate the experimental evidence for both plant defenses and viral counter-strategies, noting that many mechanistic models derive from limited model systems. We further characterize host genetic resistance and susceptibility factors applicable to crop breeding. These resources include dominant NLR and non-NLR resistance, as well as recessive resistance derived from modified host susceptibility genes. We address how viral mutations, recombination and fitness trade-offs undermine resistance durability. We then evaluate their practical deployment through conventional breeding, the exploitation of quantitative resistance, and genome editing, and outline associated agronomic drawbacks and regulatory constraints. Using ToBRFV as a case study, we analyze its epidemiological traits and assess the current arsenal of surveillance tools, from field diagnostics to remote sensing. Finally, we survey management strategies across a spectrum of maturity. Some approaches, including sanitation protocols and conventionally bred resistant cultivars, have proven effective under field conditions. The first dsRNA-based biopesticide has recently been registered in China, while other biological control agents and low-risk chemical approaches remain largely at the experimental stage. We also discuss the bottlenecks that impede lab-to-field transition and highlight promising solutions such as precision breeding and evolution-oriented cultivar deployment. By bridging molecular virology, epidemiology, and integrated disease management, this review provides a critical, bench-to-field framework for the sustainable control of tobamoviruses.

TMV↗
PubMed2026

New Insights into Genomic Variations and Mutational Events Associated with Plant-Pathogen Interactions.

Plant diseases threaten global food security, causing up to 40% crop yield losses and more than $220 billion in annual economic damage. This review synthesizes recent advances in understanding the genomic variations and mutational events underlying plant-pathogen interactions and durable plant disease resistance. Key insights into evolutionary dynamics, genetic variability, and coadaptive strategies reveal the complexity of host-pathogen relationships and the implications for developing durable disease resistance. Integrative approaches combining genome-wide association studies and functional genomics have uncovered the polygenic and epistatic architecture of quantitative resistance. Advances in pan-genomics and high-throughput sequencing have revealed extensive genetic variability in cultivated/elite germplasm and wild relatives. Emerging technologies, including gene editing, multi-omics, and machine learning, enable predictive modeling of resistance traits and support evolution that informs plant breeding strategies. Collectively, these advances provide a robust framework for developing durable resistance and sustainable crop protection in the face of global agricultural challenges.

Host-Pathogen Interactions↗
PubMed2026

Leaf Rust in Rye: From Pathogen Biology to Host Defense and Resistance Breeding.

Leaf rust (LR), caused by Puccinia recondita f. sp. secalis (Prs), is considered one of the most dangerous rye (Secale cereale L.) diseases, causing yield losses exceeding 35%. This review summarizes all currently available data about this disease: pathogen characteristics (including its life cycle, natural variation, and disease symptoms), resistance resources, and the background of the plant immune response at the genome, transcriptome, and metabolome levels. The research conducted so far has allowed for the identification of dozens of genes that play a significant role in the rye immune response to Prs infection. Among them, genes encoding NBS-LRR proteins (including SECCE1Rv1G0014220, the most likely Pr3 candidate), glycosyltransferase, β-1,3-glucanase, 1-deoxy-D-xylulose 5-phosphate synthase, β-1,3-glucanase, UDP-glycosyltransferase, pathogenesis-related protein 1, ammonium transporter, and cytochrome P450 enzymes are candidates for seedling and all-stage resistance, whereas ScLr_ABC25 currently represents the most promising candidate associated with adult-plant resistance. Among the metabolites differentially accumulated in response to Prs, those related to phenylpropanoids, diterpenoids, and thiamine branches seem to play the most important role in the immune response. Finally, we suggest how the knowledge acquired so far about the rye-Prs interaction can be used in modern breeding programs aimed at obtaining cultivars with enhanced resistance to LR, such as through the use of functional gene markers and/or metabolic biomarker-assisted selection and, in the more distant future, by developing and applying new genomic techniques for precise editing of resistance and susceptibility genes, engineering synthetic immune receptors and decoys, and pan-genomic exploration for identification of rare or lineage-specific resistance alleles. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Plant Diseases↗
PubMed2026

Dual β-lactam therapy against high-risk Pseudomonas aeruginosa isolates: a dynamic in-vitro infection model study integrating population genomics with quantitative systems pharmacology modelling and simulations.

BACKGROUND: Pseudomonas aeruginosa has an extraordinary capacity for resistance emergence during treatment, even with newer antipseudomonals. There is a gap in understanding how resistance mechanisms affect the time-course of bacterial response to these newer agents. Traditional approaches for predicting pathogen response to an antibiotic do not apply to combination therapy. We aimed to develop a modelling framework to predict treatment response based on resistome information, using isolates of the worldwide-disseminated high-risk clone sequence type (ST) 235 and β-lactam antibiotics as the example. METHODS: In this hollow-fibre in-vitro infection study, we used three extensively drug-resistant ST235 clinical isolates from the national collection of the Clinical Microbiology Department of the Hospital Son Espases (Palma de Mallorca, Spain) that were hospital-acquired, were isolated following routine microbiological procedures from different patients between 2017 and 2022, were susceptible to ceftolozane-tazobactam, and had different levels of meropenem resistance. The selected isolates (ST235-05, ST235-09, and ST235-10) showed classical β-lactam resistance mechanisms pre-treatment. The isolates were investigated in 240-h dynamic hollow-fibre in-vitro infection models (HFIMs). The studies exposed the isolates to pharmacokinetic profiles of ceftolozane-tazobactam (simulating 1 g of ceftolozane and 0·5 g of tazobactam as a 3-h infusion every 8 h) and meropenem (simulating 6 g per day continuous infusion) as observed in hospitalised patients, as monotherapy and in combination. Treatment response was assessed through the quantification of the time-courses of viable total and resistant bacteria. Whole-genome sequencing identified the mechanisms of emerging resistance. A quantitative systems pharmacology (QSP) approach was used to model total and resistant bacterial counts and corresponding pharmacokinetic data from the HFIM. Monte Carlo simulations were used to predict treatment responses in 1000 virtual infected patients treated with ceftolozane-tazobactam and meropenem as monotherapies or in combination over 10 days. FINDINGS: In the HFIMs, each antibiotic alone amplified resistance by approximately 48 h for all isolates; that is, monotherapies resulted in a higher concentration of resistant bacteria compared with the control treatment at the respective time, except ceftolozane-tazobactam against ST235-10. Combination of ceftolozane-tazobactam and meropenem was synergistic (bacterial counts ≥2 log10 colony forming units [CFU] per mL lower than the best performing monotherapy and initial inoculum) against all isolates and suppressed resistance. Against ST235-10, ceftolozane-tazobactam monotherapy reduced counts to less than 1 log10 CFU per mL from 192 h onwards, whereas the combination reached less than 1 log10 CFU per mL by 24 h. Across strains, population genomics confirmed monotherapy failures were associated with emerging resistance mechanisms (ceftolozane-tazobactam: ampC Ω-loop mutations; meropenem: ftsl mutation). The developed QSP model incorporated baseline resistance mechanisms and those emerging in resistant mutant subpopulations. The model explained and predicted the monotherapy failures involving amplification of these subpopulations, and synergistic killing and resistance suppression by the combination. Simulations using the model predicted bacterial regrowth above the initial inoculum for more than 90% of patients after 0 to approximately 3 days for meropenem monotherapy across all strains and for ceftolozane-tazobactam monotherapy against ST235-05 and ST235-09. For ceftolozane-tazobactam monotherapy against ST235-10, regrowth was predicted for approximately 30% of patients. In contrast, the simulations predicted sustained bacterial killing of at least 2 log10 CFU per mL compared with the initial inoculum by the combination for more than 89% of patients across all strains. INTERPRETATION: To our knowledge, this model is the first to characterise and predict the time-course of responses of clinical isolates to antibiotics only by the resistance mechanisms present and their complex interplay, representing a step towards pathogen-specific, personalised medicine. FUNDING: Australian National Health and Medical Research Council.

Pseudomonas aeruginosa↗
PubMed2025

Genome wide association study unveils the genetic basis of Orobanche crenata resistance in pea.

GWAS using DArTseq markers identified novel resistance sources against parasitic broomrape in pea, elucidating candidate genes for marker-selected breeding as leverage for cultivar development and efficient disease control to enhance food security. Crenate broomrape (Orobanche crenata) is an important obligate root parasitic weed that causes severe yield losses in pea (Pisum sativum) production. O. crenata is difficult to eradicate in pea fields due to its high resilience and prolific seed boom capable of hibernating in soils for decades. Existing control strategies are not cost effective in low input legumes like pea. The most efficient ecofriendly mode of control is using resistant cultivars. Quantitative trait loci (QTL) studies based on bi-parental mapping has guided O. crenata resistance discovery, albeit their deployment in pea breeding is hindered by low marker resolution and large genetic distance. This study presents the first genome-wide association study (GWAS) on O. crenata resistance in pea, utilizing 324 diverse accessions and 26,045 diversity array technology sequence (DArTseq) markers. Phenotyping was performed over four seasons under field conditions using alpha lattice design. Results showed a strong phenotypic variation with an environmental influence on O. crenata infection. Novel resistance sources were identified mainly within the wild Pisum fulvum and P. sativum subsp. elatius. GWAS with two models yielded a total of 73 marker-trait associations with Chromosome 5 as major hotspot. Interestingly, some linked markers were detected in close proximity to four previous O. crenata resistance QTL. DArTseq markers identified 24 putative candidate genes participating in different cellular processes, including vesicle trafficking and transports, deoxyribonucleic acid transcription regulation, and defense including some leucine rich repeat receptor-like kinases. These results provide a valuable genetic resource for O. crenata resistance and a step toward its effective sustainable management-to enhance genetic diversity and cultivar improvement for food security.

Pisum sativum↗
PubMed2025

Quantitative trait loci for Globodera pallida resistance derived from wild potato species Solanum gourlayi.

Globodera pallida is a major pest that is responsible for huge losses in potato yields worldwide. Expanding the gene pool of cultivated potatoes with clones resistant to this pest is made possible by searching for resistance genes in wild Solanum species. The aim of this study was to identify quantitative trait loci (QTLs) for potato resistance to Globodera pallida derived from Solanum gourlayi. A resistant diploid potato clone, Sg 2/7 (Solanum gourlayi, accession CGN17592), was crossed with a susceptible potato hybrid clone, DW 94-4235, to generate an F1 mapping population. All clones were tested for nematode resistance using G. pallida, pathotypes Pa2 and Pa3, in 2 or 3 years (2017-2019), respectively. Diversity Array Technology (DArTseq) was used for genotyping and genetic map construction. QTLs for nematode resistance were identified on potato chromosomes II, IV, V, VI, VII, X, XI, and XII, explaining from 10.1 to 21.5% of phenotypic variance. The most significant QTL for resistance to G. pallida pathotype Pa2 was identified on chromosome XII, explaining 20.9% of the phenotypic variance in the dataset from 2017. The most significant QTL for resistance to the G. pallida Pa3 pathotype was identified on chromosome VI, with a CAPS marker Exp928 in its peak, explaining 21.5% of the phenotypic variance in the dataset from 2017. The novel QTLs for resistance to S. gourlayi may be useful for breeding resistant potato cultivars, further studies of candidate genes, and host responses of potato to G. pallida infection.

Quantitative Trait Loci↗
PubMed2026

A chromosomal gtrB homolog and dam differentially contribute to dry-heat and high hydrostatic pressure resistance in Salmonella enterica.

Salmonella enterica can persist in low-moisture foods and shows enhanced dry-heat resistance under low water activity, posing significant food safety challenges. However, the genetic basis of extreme dry-heat resistance and its relationship with other processing stresses remain unclear. In this study, twelve S. enterica strains were screened for dry-heat treatment at 60 °C and 80 °C, with S. Infantis CICC21649 identified as the most resistant strain. Comparative genomics and transcriptional analysis identified candidate genes related to envelope integrity and regulation, including gtrB and dam. Deletion of the chromosomal gtrB homolog reduced dry-heat resistance, producing an additional 0.91-log10 reduction relative to the parent strain at 80 °C. Deletion of dam caused broader stress sensitivity, reducing resistance to both dry heat and high hydrostatic pressure, with the stronger phenotype observed under high hydrostatic pressure. Proteomic analysis of the chromosomal gtrB homolog mutant revealed broad alterations in envelope-associated proteins, transport functions, oxidative stress pathways, and central metabolism under dry-heat stress. These findings indicate that the chromosomal gtrB homolog is an important contributor to extreme dry-heat resistance, whereas dam contributes to resistance against both dry-heat and high hydrostatic pressure, likely through a broader regulatory role in stress adaptation. These results reveal distinct structural and regulatory layers underlying stress adaptation in S. enterica and provide practical guidance for low-moisture food processing by highlighting the need to account for strain-dependent and stress-specific resistance during process validation.

Hydrostatic Pressure↗
PubMed2026

Proteome Profiling Reveals NQO2 Activity Contributing to Proteasome Inhibitor Resistance in Multiple Myeloma Cell Lines.

Proteasome inhibitors (PIs) are frontline therapies for multiple myeloma (MM). Although MM patients initially respond to PIs, resistance frequently emerges. While all PIs nominally target the same proteasomal catalytic subunit (PSMB5), the extent to which resistance mechanisms are the same or different among different PIs or between patients is poorly understood. To address this, we performed proteome and phosphoproteome profiling of 12 MM cell line models, comprising four parental lines (AMO-1, ARH77, L363, and RPMI8226) paired with lines that acquired resistance to bortezomib (BTZ) or carfilzomib (CFZ). Over 7000 proteins and up to 10,000 phosphopeptides were identified per cell line, enabling a comprehensive comparative analysis of shared and cell line-specific resistance signatures at the protein level. Data analysis revealed surprisingly few changes in the phosphoproteome but substantial reprogramming of the proteome in most models. Beyond known adaptations such as the overexpression of the PI target PSMB5 and the drug efflux transporter ABCB1, we identified the oxidoreductases NQO1 and NQO2 as significantly upregulated proteins under chronic proteotoxic stress across several models. Pharmacological follow up in PI resistant AMO-1 cells showed that NQO2 inhibition by imatinib fully restored CFZ sensitivity, validating NQO2 as a contributor to resistance formation in this model system.

Humans↗
PubMed2026

Development of an arabinose-inducible gene expression system for nontuberculous mycobacteria.

Nontuberculous mycobacteria (NTM) are emerging pathogens for which genetic tools remain limited. Here, we developed an arabinose-inducible gene expression system based on a modified pBAD24 vector adapted for mycobacterial hosts. The vector carries replication origins for mycobacteria and Escherichia coli, as well as selectable markers compatible with NTM. In Mycobacterium abscessus (Mycobacteroides abscessus), the system enabled dose-dependent induction of target gene expression by arabinose, as demonstrated by increased antibiotic resistance and quantitative RT-PCR analysis. Although basal expression was observed in the absence of arabinose, expression levels were tunable across arabinose concentrations. The system was also functional in Mycobacterium smegmatis (Mycolicibacterium smegmatis) and Mycobacterium bovis BCG, although the degree of basal expression varied among host species. These results establish a tunable inducible expression system for mycobacteria and provide a useful genetic tool for studies of NTM biology.

Arabinose↗
PubMed2025

A retrotransposon insertion upstream of Arabidopsis thaliana CRK8 receptor-like kinase modulates a trade-off between pathogen defense and salt tolerance.

In response to necrotrophic fungal pathogens, plants often display quantitative disease resistance (QDR), an immune response with complex genetic determinants. Due to their diversity and small phenotypic effect, the genetic bases of QDR are challenging to characterize. Here, we used genome-wide association mapping in Arabidopsis thaliana natural populations to identify novel determinants of QDR against the fungal pathogen Sclerotinia sclerotiorum. We found that presence-absence polymorphism of the AT4TE56270 Copia transposable element (TE) upstream of the cysteine-rich receptor-like kinase 8 (CRK8) gene is associated with QDR. The presence of the TE associates with higher CRK8 expression in healthy and inoculated plants and increased QDR. The constitutive knockdown of CRK8 reduced QDR, hydrogen peroxide production, and the expression of defense genes upon inoculation. Transcriptome analysis revealed altered defense pathways and salt responses in CRK8 mutants, including impaired glutathione and camalexin biosynthesis, likely contributing to disease susceptibility. Mutants in CRK8 showed altered seed germination on salt, and the absence of AT4TE56270 is associated with enhanced seed germination under salt stress in A. thaliana natural populations. These results reveal a trade-off between salt tolerance and defense against S. sclerotiorum associated with presence-absence polymorphism of a TE.

Arabidopsis↗
PubMed2026

Quantitative interactome mapping of skeletal muscle insulin resistance.

Protein-protein interactions (PPIs) are dynamic and critical to adaptive homeostasis. While there have been massive efforts to catalogue proteome-wide PPIs, global quantification of changes remains a challenge. Here, we integrate dynamic protein correlation profiling - mass spectrometry (PCP-MS) and quantitative cross linking-mass spectrometry (qXL-MS) using multiplexed stable isotope labelling to characterise global PPI remodelling following the development of chronic skeletal muscle insulin resistance (IR) with or without acute insulin stimulation. We quantify >7,000 unique PPIs amongst 5,346 proteins and show changes in the interactome network dominate the proteome response. Our data show the dysregulation of protein processing in the endoplasmic/sarcoplasmic reticulum involving changes in PPIs with protein chaperones and disulfide isomerases is a major hallmark of skeletal muscle IR. Mechanistically, we show the dysregulation of PPIs with Protein-Disulfide Isomerase 6 (PDIA6) regulates cysteine oxidation and insulin sensitivity. Taken together, we show in vivo quantitative interactome mapping is a powerful approach to understand disease mechanisms and provide new insights into protein network re-organisations with IR.

Insulin Resistance↗
PubMed2026

Large-Scale Genomic Analysis of Stripe Rust Resistance in Chinese Wheat Germplasm Using Multi-Environment Trial Data.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a significant disease affecting global wheat crops and causing substantial economic losses. This study aimed to identify effective resistance genes by evaluating 120 common wheat accessions from diverse regions in China. These samples were tested with three Pst races at the seedling stage and with natural Pst inoculum at four field locations in three crop seasons. Genotypic data were collected through a Wheat55K iSelect single-nucleotide polymorphism array. The genome-wide association study identified 17 distinct loci linked to stripe rust response, accounting for 1.07 to 30.58% of the phenotypic variation across trials. These loci were distributed among three wheat genome groups: 2 in Group A, 10 in Group B, and 5 in Group D. Among these, eight loci overlapped with the reported stripe rust resistance genes or quantitative trait loci, while nine loci were novel and mainly distributed on chromosomes 2A, 6B, and 7D. This research enhances the understanding of genetic mechanisms underlying wheat stripe rust resistance and provides valuable germplasm resources for breeding new cultivars with enhanced disease resilience.

Puccinia striiformis f. sp. tritici↗
PubMed2025

The toxin-antitoxin system SavRS contributes to vancomycin resistance in vancomycin-intermediate Staphylococcus aureus by mediating cell wall thickening.

BACKGROUND: The emergence of vancomycin-intermediate Staphylococcus aureus (VISA) has significantly challenged the treatment of S. aureus infection. Toxin-antitoxin (TA) systems have been reported to mediate bacterial stress adaptation and virulence, but their role in vancomycin resistance remains elusive. This study investigated the vancomycin resistance mechanism regulated by the TA system SavRS in VISA. METHODS: savRS mutants in Mu50 and XN108 were generated via homologous recombination. To investigate the regulatory mechanism of vancomycin resistance mediated by savRS in VISA, phenotypic analyses including MICs, growth kinetics and cell wall thickness measurements were performed. Expression of cell wall synthesis-related genes was analysed using quantitative RT-PCR (RT-qPCR) and promoter-lacZ reporter assay. Electrophoretic mobility shift assay (EMSA) was performed to assess the binding of SavRS to the promoters of the cell wall synthesis-related genes. Pull-down assay identified an upstream regulatory element of savRS associated with vancomycin resistance. Quantitative assessment of bacterial burden in murine organ systems following vancomycin administration revealed the critical regulatory role of savRS in mediating vancomycin resistance in vivo. RESULTS: Compared with the WT, the savRS mutant exhibited enhanced vancomycin sensitivity, accelerated growth and reduced cell wall thickness. Correspondingly, RT-qPCR revealed marked down-regulation of the cell wall synthesis-related genes (glyS, dltA, scdA, pbp2, ddl). EMSA and promoter-lacZ reporter assay confirmed direct binding of SavRS to a conserved promoter motif, MGHYYTCCTCA. Pull-down assay identified UspA as an upstream regulator of SavRS, demonstrating that UspA directly controls savRS transcription and modulates VISA resistance. Mouse infection experiments showed that savRS promotes VISA to vancomycin resistance in vivo. CONCLUSIONS: SavRS critically regulates vancomycin resistance in VISA.

Cell Wall↗
PubMed2026

Antibody-drug conjugates against multidrug-resistant cancers: Biomarker-guided patient selection, payload engineering, linker chemistry, and bystander effects.

Antibody-drug conjugates (ADCs) are one of the most significant advancements in modern cancer therapeutics. Combining the target selectivity of monoclonal antibodies with the cytotoxic potential of payloads, ADCs effectively kill cancer cells and offer hope to patients with even refractory cancer types. Beyond simply increasing the number of therapeutic options available for cancer patients, ADCs have become a powerful frontline agent in overcoming multidrug resistance (MDR). As one of the most challenging obstacles to effective cancer care, MDR is mediated by ATP-binding cassette (ABC) transporter-mediated drug efflux, target-based mutations, and dysregulated apoptosis. The clinical success of ADCs specifically engineered to overcome MDR, including in heterogeneous tumors and cancer cells that exhibit bypass signaling, is well established. This is especially evident with trastuzumab deruxtecan (T-DXd) in HER2-low, HER2-positive, and HER2-mutant cancers; sacituzumab govitecan (SG) in TROP2-expressing triple-negative breast cancer (TNBC) and urothelial carcinoma; and enfortumab vedotin in Nectin-4-positive bladder cancer. By overcoming MDR, ADCs have enabled more effective treatment algorithms across multiple malignancies. Most importantly, the clinical application of ADCs has become inextricably linked to cancer genomics. HER2 testing has evolved from a two-tiered system to a continuous spectrum including HER2-ultralow, HER2-low, HER2-positive, and ERBB2-mutant categories. Each of these categories exhibits different eligibility guidelines for ADC patient selection. As cancer cells continue to evolve and develop resistance to even ADCs through mutations and variants, researchers and clinicians have used pharmacogenomics to predict ADC response and resistance. To define the genomic architecture of ADC-resistant tumor subpopulations, single-cell transcriptomic studies and liquid biopsy approaches are being used to enable real-time examination of the tumor genome during ADC therapy, thereby optimizing treatment and circumventing resistance driven by emerging mutations and variants. This review provides a comprehensive analysis of the molecular structure of ADCs, the pharmacological principles underlying their potent cytotoxic activity against MDR cancer cells, the genomic and transcriptomic biomarkers that guide ADC patient selection, and the emerging resistance mechanisms that will shape the next generation of promising ADC development.

Humans↗
PubMed2025

Naturally occurring variation in a cytochrome P450 modifies thiabendazole responses independently of beta-tubulin.

Widespread anthelmintic resistance has complicated the management of parasitic nematodes. Resistance to the benzimidazole (BZ) drug class is nearly ubiquitous in many species and is associated with mutations in beta-tubulin genes. However, mutations in beta-tubulin alone do not fully explain all BZ resistance. We performed a genome-wide association study using a genetically diverse panel of Caenorhabditis elegans strains to identify loci that contribute to resistance to the BZ drug thiabendazole (TBZ). We identified a quantitative trait locus (QTL) on chromosome V independent of all beta-tubulin genes and overlapping with two promising candidate genes, the cytochrome P450 gene cyp-35D1 and the nuclear hormone receptor nhr-176. Both genes were previously demonstrated to play a role in TBZ metabolism. NHR-176 binds TBZ and induces the expression of CYP-35D1, which metabolizes TBZ. We generated single gene deletions of cyp-35D1 and nhr-176 and found that both genes play a role in TBZ response. A predicted high-impact lysine-to-glutamate substitution at position 267 (K267E) in CYP-35D1 was identified in a sensitive strain, and reciprocal allele replacement strains in different genetic backgrounds were used to show that the lysine allele conferred increased TBZ resistance. Using competitive fitness assays, we found that neither allele was deleterious, but the lysine allele was selected in the presence of TBZ. Additionally, we found that the lysine allele significantly increased the rate of TBZ metabolism compared to the glutamate allele. Moreover, yeast expression assays showed that the lysine version of CYP-35D1 had twice the enzymatic activity of the glutamate allele. To connect our results to parasitic nematodes, we analyzed four Haemonchus contortus cytochrome P450 orthologs but did not find variation at the 267 position in fenbendazole-resistant populations. Overall, we confirmed that variation in this cytochrome P450 gene is the first locus independent of beta-tubulin to play a role in BZ resistance.

Animals↗
PubMed2025

Tumor microenvironment governs the prognostic landscape of immunotherapy for head and neck squamous cell carcinoma: A computational model-guided analysis.

Immune checkpoint inhibition (ICI) has emerged as a critical treatment strategy for squamous cell carcinoma of the head and neck (HNSCC) that halts the immune escape of the tumor cells. Increasing evidence suggests that the onset, progression, and lack of/no response of HNSCC to ICI are emergent properties arising from the interactions within the tumor microenvironment (TME). Deciphering how the diversity of cellular and molecular interactions leads to distinct HNSCC TME subtypes subsequently governing the ICI response remains largely unexplored. We developed a cellular-molecular model of the HNSCC TME that incorporates multiple cell types, cellular states, and transitions, and molecularly mediated paracrine interactions. Simulation across the selected parameter space of the HNSCC TME network shows that distinct mechanistic balances within the TME give rise to the five clinically observed TME subtypes such as immune/non-fibrotic, immune/fibrotic, fibrotic only and immune/fibrotic desert. We predict that the cancer-associated fibroblast, beyond a critical proliferation rate, drastically worsens the ICI response by hampering the accessibility of the CD8 + killer T cells to the tumor cells. Our analysis reveals that while an Interleukin-2 (IL-2) + ICI combination therapy may improve response in the immune desert scenario, Osteopontin (OPN) and Leukemia Inhibition Factor (LIF) knockout with ICI yields the best response in a fibro-dominated scenario. Further, we predict Interleukin-8 (IL-8), and lactate can serve as crucial biomarkers for ICI-resistant HNSCC phenotypes. Overall, we provide an integrated quantitative framework that explains a wide range of TME-mediated resistance mechanisms for HNSCC and predicts TME subtype-specific targets that can lead to an improved ICI outcome.

Tumor Microenvironment↗