Synthetic Peptides Research Articles

Allosterism in the adenosine A2A and cannabinoid CB2 heteromer.

Allosterism is a regulatory mechanism for GPCRs that can be attained by ligand-binding or protein-protein interactions with another GPCR. We have studied the influence of the dimer interface on the allosteric properties of the A2A receptor and CB2 receptor heteromer. We have evaluated cAMP production, phosphorylation of signal-regulated kinases (pERK1/2), label-free dynamic mass redistribution, β-arrestin 2 recruitment and bimolecular fluorescence complementation assays in the absence and presence of synthetic peptides that disrupt the formation of the heteromer. Molecular dynamic simulations provided converging evidence that the heteromeric interface influences the allosteric properties of the A2AR-CB2R heteromer. Apo A2AR blocks agonist-induced signalling of CB2R. The disruptive peptides, with the amino acid sequence of transmembrane (TM) 6 of A2AR or CB2R, facilitate CB2R activation, suggesting that A2AR allosterically prevents the outward movement of TM 6 of CB2R for G protein binding. Significantly, binding of the selective antagonist SCH 58261 to A2AR also facilitated agonist-induced activation of CB2R. It is proposed that the A2AR-CB2R heteromer contains distinct dimerization interfaces that govern its functional properties. The molecular interface between protomers of the A2AR-CB2R heteromer interconverted from TM 6 for apo or agonist-bound A2AR, blocking CB2R activation, to mainly the TM 1/7 interface for antagonist-bound A2AR, facilitating the independent opening of intracellular cavities for G protein binding. These novel results shed light on a different type of allosteric mechanism and extend the repertoire of GPCR heteromer signalling.

Total Synthesis Facilitates In Vitro Reconstitution of the C-S Bond-Forming P450 in Griseoviridin Biosynthesis.

Griseoviridin is a group A streptogramin natural product from Streptomyces with broad-spectrum antibacterial activity. A hybrid polyketide-nonribosomal peptide, it comprises a 23-membered macrocycle, an embedded oxazole motif, and a macrolactone with a unique ene-thiol linkage. Recent analysis of the griseoviridin biosynthetic gene cluster implicated SgvP, a cytochrome P450 monooxygenase, in late-stage installation of the critical C-S bond. While genetic and crystallographic experiments provided indirect evidence to support this hypothesis, the exact function of SgvP has never been confirmed biochemically. Herein, we report a convergent total synthesis of pre-griseoviridin, the putative substrate of P450 SgvP and precursor to griseoviridin. Our strategy features concise and rapid assembly of two fragments joined via sequential peptide coupling and Stille macrocyclization. Access to pre-griseoviridin then enabled in vitro validation of SgvP as the C-S bond-forming P450 during griseoviridin biosynthesis, culminating in a nine-step chemoenzymatic synthesis of griseoviridin.

Peptide Nucleic Acid-Mediated Regulation of CRISPR-Cas9 Specificity.

Although CRISPR-Cas9 gene therapies have proven to be a powerful tool across many applications, improvements are necessary to increase the specificity of this technology. Cas9 cutting in off-target sites remains an issue that limits CRISPR's application in human-based therapies. Treatment of autosomal dominant diseases also remains a challenge when mutant alleles differ from the wild-type sequence by only one base pair. Here, we utilize synthetic peptide nucleic acids (PNAs) that bind selected spacer sequences in the guide RNA (gRNA) to increase Cas9 specificity up to 10-fold. We interrogate variations in PNA length, binding position, and degree of homology with the gRNA. Our findings reveal that PNAs bound in the region distal to the protospacer adjacent motif (PAM) site effectively enhance specificity in both on-target/off-target and allele-specific scenarios. In addition, we demonstrate that introducing deliberate mismatches between PNAs bound in the PAM-proximal region of the gRNA can modulate Cas9 activity in an allele-specific manner. These advancements hold promise for addressing current limitations and expanding the therapeutic potential of CRISPR technology.

The Role of Structural Flexibility in Hydrocarbon‐Stapled Peptides Designed to Block Viral Infection via Human ACE2 Mimicry

ABSTRACTThe COVID‐19 pandemic drove a uniquely fervent pursuit to explore the potential of peptide, antibody, protein, and small‐molecule‐based antiviral agents against severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). The interaction between the SARS‐CoV2 spike protein with the angiotensin‐converting enzyme 2 (ACE2) receptor that mediates viral cell entry was a particularly interesting target given its well‐described protein–protein interaction (PPI). This PPI is mediated by an α‐helical portion of ACE2 binding to the receptor binding domain (RBD) of the spike protein and thought to be susceptible to blockade through molecular mimicry. Small numbers of hydrocarbon‐stapled synthetic peptides designed to disrupt or block this interaction were tested individually and were found to have variable efficacy despite having related or overlapping sequences and similarly increased α‐helicity. Reasons for these differences are unclear and reported preclinical successes have been limited. This study sought to better understand reasons for these differences through evaluation of a comprehensive collection of hydrocarbon‐stapled peptides, designed based on four distinct principles: stapling position, number of staples, amino acid sequence, and primary sequence length. Surprisingly, we observed that the helicity and amino acid sequence iterations of hydrocarbon‐stapled peptides did not correlate with their bioactivity. Our results highlight the importance of iterative and combinatorial testing of these compounds to determine a configuration that best mimics natural binding and allows for chain flexibility while sacrificing structural helicity.

Tick-Borne pathogens and defensin genes expression: A closer look at Ixodes ricinus and Dermacentor reticulatus

The immune system of ticks, along with that of other invertebrates, is comparatively simpler than that of vertebrates, relying solely on innate immune responses. Direct antimicrobial defence is provided by the synthesis of antimicrobial peptides (AMPs), including defensins. The aim of this study was to investigate the differences in defensin genes expression between questing and engorged Ixodes ricinus (def1 and def2) and Dermacentor reticulatus (defDr) ticks, in the presence of selected pathogens: Borrelia spp., Rickettsia spp., Babesia spp., Anaplasma phagocytophilum, and Neoehrlichia mikurensis in the natural environment. After pathogen screening by PCR/qPCR, the expression of defensin genes in pathogen positive ticks and ticks without any of the tested pathogens, was analysed by reverse transcription qPCR. The results showed an increased expression of defensin genes in I. ricinus ticks after blood feeding and I. ricinus and D. reticulatus ticks during in cases of co-infection. In particular, the expression of defensins genes was higher in questing D. reticulatus than in questing and engorged I. ricinus ticks, when borreliae were detected. This study contributes to uncovering the expression patterns of defensin genes in the presence of several known tick pathogens, the occurrence of these pathogens and possible regulatory mechanisms of defensins in tick vector competence.

Inclusion of TAT and NLS sequences in lipopeptide molecules generates homogenous nanoparticles for gene delivery applications

PurposesThe objective of this study is to develop a versatile gene carrier based on lipopeptides capable of delivering genetic material into target cells with minimal cytotoxicity. MethodsTwo lipopeptide molecules, palmitoyl-CKKHH and palmitoyl-CKKHH-YGRKKRRQRRR-PKKKRKV, were synthesized using solid phase peptide synthesis and evaluated as transfection agents. Physicochemical characterization of the lipopeptides included a DNA shift mobility assay, particle size measurement, and transmission electron microscopy (TEM) analysis. Cytotoxicity was assessed in CHO-K1 and HepG2 cells using the MTT assay, while transfection efficiency was determined by evaluating the expression of the green fluorescent protein-encoding gene. ResultsOur findings demonstrate that the lipopeptides can bind, condense, and shield DNA from DNase degradation. The inclusion of the YGRKKRRQRRR sequence, a transcription trans activator, and the PKKKRKV sequence, a nuclear localization signal, imparts desirable properties. Lipopeptide-based TAT-NLS/DNA nanoparticles exhibited stability for up to 20 days when stored at 6–8 °C, displaying uniformity with a compact size of approximately 120 nm. Furthermore, the lipopeptides exhibited lower cytotoxicity compared to the poly-L-lysine. Transfection experiments revealed that protein expression mediated by the lipopeptide occurred at a charge ratio ranging from 4.0 to 8.0. ConclusionThese results indicate that the lipopeptide, composed of a palmitoyl alkyl chain and TAT and NLS sequences, can efficiently condense and protect DNA, form stable and uniform nanoparticles, and exhibit promising characteristics as a potential gene carrier with minimal cytotoxicity.

Synthesis of hexafluorovaline-containing di- and tripeptides

A new strategy for the synthesis of peptides incorporating racemic hexafluorovaline (hfVal) is presented. The synthetic pathway relies on the anti-Michael addition of benzyl amine derivatives to ad hoc prepared β-bis-trifluoromethyl-acryloyl-α-amino esters which proceeds in mild condition, high yields, even if with low stereocontrol. The following elaboration of the intermediates, namely deprotection of the benzyl moiety and coupling with α-amino esters allowed us to synthetize the targeted tripeptides in four overall synthetic steps, resulting in a synthetic pathway more favorable respect to those appeared in literature based on the synthesis and isolation of racemic Boc-hfVal-OH (eight synthetic steps).

Crafting Unnatural Peptide Macrocycles via Rh(III)-Catalyzed Carboamidation.

Contemporary developments in the field of peptide macrocyclization methodology are imperative for enabling the advance of drug design in medicinal chemistry. This report discloses a Rh(III)-catalyzed macrocyclization via carboamidation, reacting acryloyl-peptide-dioxazolone precursors and arylboronic acids to form complex cyclic peptides with concomitant incorporation of noncanonical α-amino acids. The diverse and modular technology allows for expedient access to a wide variety of cyclic peptides from 4 to 15 amino acids in size and features simultaneous formation of unnatural phenylalanine and tyrosine derivatives with up to >20:1 diastereoselectivity. The reaction showcases an expansive substrate scope with 45 examples and is compatible with the majority of standard protected amino acids used in Fmoc-solid phase peptide synthesis. The methodology is applied to the synthesis of multiple peptidomimetic macrocyclic analogs, including derivatives of cyclosomatostatin and gramicidin S.

Human estrogen receptor alpha (ERα) targeted cyclic peptides inhibit cell growth and induce apoptosis in MCF-7 cells

Abstract Objectives Human estrogen receptor alpha (ERα) is considered an important target, especially in the treatment of breast cancer, as it has a vital role in cancer development. ERα-targeted therapies generally target the ligand binding domain (LBD) of ERα. However, over time, cells develop resistance to this mechanism alternative approaches to inhibit ERα activity target ERα–DNA or ERα–cofactor interactions. Inhibitors of ERα–cofactor interactions are designed by targeting the hydrophobic hollow region of the receptor box LXXLL motif. Methods In this context, helix-stabilized cyclic peptides (SPs) designed with in silico approaches were obtained by solid phase peptide synthesis. The effects of SPs on MCF-7 cells were examined with MTT and ATP, and qPCR and flow cytometry were used for further analysis. Results Our results demonstrated that the SPs were effective only in MCF-7 cells expressing ERα. In addition, cyclic peptide combinations (SPCs) showed anti-proliferative and toxic effects on MCF-7 cells. The impact of SPCs with the highest inhibitory effect in MCF-7 cells on ERα-related genes and markers of apoptosis was revealed. Moreover, the flow cytometry analysis result used to examine apoptotic cells proved the apoptosis of SPCs in MCF-7 cells. Conclusions These findings suggest that our novel SPs, which inhibit coactivator interactions of ERα, induce apoptosis of MCF-7 cells. Thus, considering this strong effect of SPs in the inhibition of receptors, it is pointed out that they can be further developed as an alternative to current clinical treatments or as an auxiliary approach in the generating of new targeted peptide-based therapies.

Human Biodistribution and Radiation Dosimetry of the Targeting Fibroblast Growth Factor Receptor 1-Positive Tumors Tracer [68Ga]Ga-DOTA-FGFR1-Peptide.

Objective: [68Ga]Ga-DOTA-FGFR1-peptide is a novel positron emission tomography (PET) radiotracer targeting fibroblast growth factor receptor 1 (FGFR1). This study aimed to evaluate the safety, biodistribution, radiation dosimetry, and imaging potential of [68Ga]Ga-DOTA-FGFR1-peptide. Methods: The FGFR1-targeting peptide DOTA-(PEG2)-KAEWKSLGEEAWHSK was synthesized by manual solid-phase peptide synthesis and high-performance liquid chromatography purification, and labeled with 68Ga with DOTA as chelating agent. We recruited 14 participants and calculated the radiation dose of 4 of these pathologically confirmed nontumor subjects using OLINDA/EXM 2.2.0 software. At the same time, the imaging potential in 10 of these lung cancer patients was evaluated. Results: The biodistribution of [68Ga]Ga-DOTA-FGFR1-peptide in 4 subjects showed the highest uptake in the bladder and kidney. Dosimetry analysis indicated that the bladder wall received the highest effective dose (3.73E-02 mSv/MBq), followed by the lungs (2.36E-03 mSv/MBq) and red bone marrow (2.09E-03 mSv/MBq). No normal organs were found to have excess specific absorbed doses. The average systemic effective dose was 4.97E-02 mSv/MBq. The primary and metastatic tumor lesions were clearly visible on PET/computed tomography (CT) images in 10 patients. Conclusion: Our results indicate that [68Ga]Ga-DOTA-FGFR1-peptide has a good dosimetry profile and can be used safely in humans, and it has significant potential value for clinical PET/CT imaging.

Secretomic changes of amyloid beta peptides on Alzheimer's disease related proteins in differentiated human SH-SY5Y neuroblastoma cells.

Alzheimer's disease (AD) is a neurodegenerative disease that causes physical damage to neuronal connections, leading to brain atrophy. This disruption of synaptic connections results in mild to severe cognitive impairments. Unfortunately, no effective treatment is currently known to prevent or reverse the symptoms of AD. The aim of this study was to investigate the effects of three synthetic peptides, i.e., KLVFF, RGKLVFFGR and RIIGL, on an AD in vitro model represented by differentiated SH-SY5Y neuroblastoma cells exposed to retinoic acid (RA) and brain-derived neurotrophic factor (BDNF). The results demonstrated that RIIGL peptide had the least significant cytotoxic activity to normal SH-SY5Y while exerting high cytotoxicity against the differentiated cells. The mechanism of RIIGL peptide in the differentiated SH-SY5Y was investigated based on changes in secretory proteins compared to another two peptides. A total of 380 proteins were identified, and five of them were significantly detected after treatment with RIIGL peptide. These secretory proteins were found to be related to microtubule-associated protein tau (MAPT) and amyloid-beta precursor protein (APP). RIIGL peptide acts on differentiated SH-SY5Y by regulating amyloid-beta formation, neuron apoptotic process, ceramide catabolic process, and oxidative phosphorylation and thus has the potentials to treat AD.

Bioactivity of synthetic peptides from Ecuadorian frog skin secretions against Leishmania mexicana, Plasmodium falciparum, and Trypanosoma cruzi.

Chagas disease, leishmaniasis, and malaria are major parasitic diseases disproportionately affecting the underprivileged population in developing nations. Finding new, alternative anti-parasitic compounds to treat these diseases is crucial because of the limited number of options currently available, the side effects they cause, the need for long treatment courses, and the emergence of drug-resistant parasites. Anti-microbial peptides (AMPs) derived from amphibian skin secretions are small bioactive molecules capable of lysing the cell membrane of pathogens while having low toxicity against human cells. Here, we report the anti-parasitic activity of five AMPs derived from skin secretions of three Ecuadorian frogs: cruzioseptin-1, cruzioseptin-4 (CZS-4), and cruzioseptin-16 from Cruziohyla calcarifer; dermaseptin-SP2 from Agalychnis spurrelli; and pictuseptin-1 from Boana picturata. These five AMPs were chemically synthesized. Initially, the hemolytic activity of CZS-4 and its minimal inhibitory concentration against Escherichia coli, Staphylococcus aureus, and Candida albicans were determined. Subsequently, the cytotoxicity of the synthetic AMPs against mammalian cells and their anti-parasitic activity against Leishmania mexicana promastigotes, erythrocytic stages of Plasmodium falciparum and mammalian stages of Trypanosoma cruzi were evaluated in vitro. The five AMPs displayed activity against the pathogens studied, with different levels of cytotoxicity against mammalian cells. In silico molecular docking analysis suggests this bioactivity may occur via pore formation in the plasma membrane, resulting in microbial lysis. CZS-4 displayed anti-bacterial, anti-fungal, and anti-parasitic activities with low cytotoxicity against mammalian cells. Further studies about this promising AMP are required to gain a better understanding of its activity.IMPORTANCEChagas disease, malaria, and leishmaniasis are major tropical diseases that cause extensive morbidity and mortality, for which available treatment options are unsatisfactory because of limited efficacy and side effects. Frog skin secretions contain molecules with anti-microbial properties known as anti-microbial peptides. We synthesized five peptides derived from the skin secretions of different species of tropical frogs and tested them against cultures of the causative agents of these three diseases, parasites known as Trypanosoma cruzi, Plasmodium falciparum, and Leishmania mexicana. All the different synthetic peptides studied showed activity against one of more of the parasites. Peptide cruzioseptin-4 is of special interest since it displayed intense activity against parasites while being innocuous against cultured mammalian cells, which indicates it does not simply hold general toxic properties; rather, its activity is specific against the parasites.

How Useful are Antimicrobial Peptide Properties for Predicting Activity, Selectivity, and Potency?

Antimicrobial peptides (AMPs) are recognized for their potential application as new generation antibiotics, however, up to date, they have not been widely commercialized as expected. Although current bioinformatic tools can predict antimicrobial activity based on only amino acid sequences with astounding accuracy, peptide selectivity and potency are not foreseeable. This, in turn, creates a bottleneck not only in the discovery and isolation of promising candidates but, most importantly, in the design and development of novel synthetic peptides. In this paper, we discuss the challenges faced when trying to predict peptide selectivity and potency, based on peptide sequence, structure and relevant biophysical properties such as length, net charge and hydrophobicity. Here, pore-forming alpha-helical antimicrobial peptides family isolated from anurans was used as the case study. Our findings revealed no congruent relationship between the predicted peptide properties and reported microbial assay data, such as minimum inhibitory concentrations against microorganisms and hemolysis. In many instances, the peptides with the best physicochemical properties performed poorly against microbial strains. In some cases, the predicted properties were so similar that differences in activity amongst peptides of the same family could not be projected. Our general conclusion is that antimicrobial peptides of interest must be carefully examined since there is no universal strategy for accurately predicting their behavior.

Novel Delivery Systems for Oral Administration of Enfuvirtide: New Treatment Options for HIV/AIDS

AbstractEnfuvirtide (T‐20) is a synthetic peptide fusion inhibitor for the human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS). However, the peptide nature limits a wider application of T‐20 with subcutaneous injection (Fuzeon) the only available formulation. In this groundbreaking study, it is sought to overcome this limitation by employing poly lactic‐co‐glycolic acid (PLGA) and alginate to create novel oral delivery systems for T‐20. Remarkably, this investigation marks the first instance of assessing the efficacy of oral delivery systems in mice. Notably, both the PLGA and alginate formulations exhibit the capability to sustain T‐20 release, maintaining detectable levels in the bloodstream of mice for over 24 h after a single dose. By venturing into the realm of oral T‐20 delivery, this study opens avenues for the prospective development of oral formulations of T‐20, potentially leading to their evaluation in clinical trials.

Development of Novel Amino Acids Containing N‐mercaptophenetyl (MPE)‐type Auxiliary and Orthogonal Protecting Groups for Sequential Ligation of Multiple Peptides

AbstractChemoselective peptide ligation using ligation auxiliaries is a powerful methodology to extend the scope of native chemical ligation beyond ligation at Cys. Herein, we report the development of novel amino acids containing an N‐mercaptophenethyl (MPE)‐type auxiliary and protecting groups (i. e., tert‐butyloxycarbonyl (Boc), 1,3‐thiazolidine (Thz), and allyloxycarbonyl (Alloc)). These developed amino acids can be introduced into a peptide via 9‐fluorenylmethoxycarbonyl‐based solid‐phase peptide synthesis, enabling deprotection and native chemical ligation in one pot. The combination of Thz‐type and Alloc‐type acids enables sequential peptide ligation, which is applicable to the synthesis of peptides branched from a Lys side chain. We also found that the multiple N‐MPE groups are efficiently cleaved upon treatment with tris(2‐carboxyethyl)phosphine and morpholine in the presence of SnCl2.

Bioproduction Platform to Generate Functionalized Disulfide-Constrained Peptide Analogues.

Disulfide-constrained peptides (DCPs) have gained increased attention as a drug modality due to their exceptional stability and combined advantages of large biologics and small molecules. Chemical synthesis, although widely used to produce DCPs, is associated with high cost, both economically and environmentally. To reduce the dependence on solid phase peptide synthesis and the negative environmental footprint associated with it, we present a highly versatile, low-cost, and environmentally friendly bioproduction platform to generate DCPs and their conjugates as well as chemically modified or isotope-labeled DCPs. Using the DCP against the E3 ubiquitin ligase Zinc and Ring Finger 3, MK1-3.6.10, as a model peptide, we have demonstrated the use of bacterial expression, combined with Ser ligation or transglutaminase-mediated XTEN ligation, to produce multivalent MK1-3.6.10 and MK1-3.6.10 with N-terminal functional groups. We have also developed a bioproduction method for the site-specific incorporation of unnatural amino acids into recombinant DCPs by the amber codon suppression system. Lastly, we produced 15N/13C-labeled MK1-3.6.10 with high yield and assessed the performance of a semiautomated resonance assignment workflow that could be used to accelerate binding studies and structural characterization of DCPs. This study provides a proof of concept to generate functionalized DCPs using bioproduction, providing a potential solution to alleviate the reliance on hazardous chemicals, reduce the cost, and expedite the timeline for DCP discovery.

Hypervalent Iodine Amino Acid Building Blocks for Bioorthogonal Peptide Macrocyclization

AbstractEthynylbenziodoxol(on)es (EB(X)xs) reagents have emerged as useful reagents for peptide/protein modification due to their versatile reactivity and high selectivity. Herein, we report the successful introduction of ethynylbenziodoxoles (EBxs) on different amino acid building blocks (Lys/Orn/Dap), and show their compatibility with both solid phase peptide synthesis (SPPS) and solution phase peptide synthesis (SPS). The selective incorporation of the EBx core into peptide sequences enable efficient macrocyclizations under mild conditions for the synthesis of topologically unique cyclic and bicyclic peptides.

Hypervalent Iodine Amino Acid Building Blocks for Bioorthogonal Peptide Macrocyclization.

Ethynylbenziodoxol(on)es (EB(X)xs) reagents have emerged as useful reagents for peptide/protein modification due to their versatile reactivity and high selectivity. Herein, we report the successful introduction of ethynylbenziodoxoles (EBxs) on different amino acid building blocks (Lys/Orn/Dap), and show their compatibility with both solid phase peptide synthesis (SPPS) and solution phase peptide synthesis (SPS). The selective incorporation of the EBx core into peptide sequences enable efficient macrocyclizations under mild conditions for the synthesis of topologically unique cyclic and bicyclic peptides.

Identification of Immunodominant Epitopes of Dengue Virus 2 Envelope and NS1 Proteins: Evaluating the Diagnostic Potential of a Synthetic Peptide.

Dengue is a major infectious disease with potential for outbreaks and epidemics. A specific and sensitive diagnosis is a prerequisite for clinical management of the disease. We designed our study to identify epitopes on theDengue virus (DENV) envelope (E) and non-structural protein 1 (NS1) with potential for diagnosis. Serology and immunoinformatic approaches were employed. We collected DENV-positive, DENV-negative and Japanese encephalitis virus-positive samples from collaborating hospitals in 2019 and 2022-2023. Seropositive peptides in 15-18 mer peptide arrays of E and NS1 proteins of DENV2 were determined by an indirect enzyme-linked immunosorbent assay. B-cell linear and conformational epitopes were predicted using BepiPred2.0 and ElliPro, respectively. A consensus recombinant peptide was designed, synthesised and evaluated for its diagnostic potential using patient sera. Eight peptides of E protein and six peptides of NS1 protein were identified to be the most frequently recognised by Dengue-positive patients. These peptide sequences were compared with B-cell epitope regions and found to be overlapped with predicted B-cell linear and conformational epitopes. EP11 and NSP15 showed a 100% amino acid sequence overlap with B-cell epitopes. EP1 and NSP15 had 14 whereas EP28, EP31, EP60 16, NSP12 and NSP32 had more than 15 interacting interface residues with a neutralising antibody, suggesting a strength of interaction. Interestingly, potential epitopes identified were localised on the surface of proteins as visualised by PyMOL. Validation with a recombined synthetic peptide yielded 92.3% sensitivity and 91.42% specificity. Immunodominant regions identified by serology and computationally predicted epitopes overlapped, thereby showing the robustness of the methodology and the peptide designedfor diagnosis.

The transcriptomic landscape of Botrytis cinerea infection on postharvest grapes sheds light on the biological function of the Bcnrps1 gene

Botrytis cinerea, a prevalent necrotrophic fungal pathogen, causes significant postharvest infections including fruits. This pathogen exploits senescent tissues, resulting in significant economic losses. During the Botrytis-plant interaction, a molecular cross-talk is established between the host and the pathogen, mediated by the interplay of the plant's defense pathways and the phytopathogenic fungus's virulence pathways, which are modulated by abiotic and biotic factors.The Bcnrps1 genes is secondary metabolims gene that encodes a non-ribosomal peptide synthetase. This family enzyme is responsible for the synthesis of natural peptides with a wide range of biological activities. Although the function of the majority of these peptides remains elusive, they could evolve in plant-pathogen interaction during infection process. Deletion of the Bcnrps1 gene increases the virulence of the pathogen otherwise, a reduction in sensitivity to toxic compounds such as spermidine and the fungicide pyrimethanil is observed. A transcriptome analysis was performed in this study to comprehensively elucidate the behavior of this mutant and to assess the molecular dynamics both in Bcnrps1 mutant and wild-type strains during the infection process of harvested white grapes. The number of differentially expressed genes (DEGs) during infection differs significantly between the B. cinerea B05.10 strain and the ΔBcnrps1 strain. The results demonstrate that, during white grape infection, the mutant induces genes related to five main functional groups: detoxification, transcription factors, CAZymes, virulence factors, and secondary metabolism. These findings underscore the crucial role of the Bcnrps1 gene in mediating the fungal response to environmental stressors and plant-derived substances during plant-pathogen interactions, as supported by observed gene expression patterns.