Potential use of yeast protein in terms of biorefinery, functionality, and sustainability in food industry.

A growing demand for sustainable, alternative protein sources that are nutrient-dense, such as microorganisms, and insects, has gradually evolved. When paired with effective processing techniques, yeast cells contain substantial substances that could supply the population's needs for food, medicine, and fuel. This review article explores the potential of yeast proteins as a sustainable and viable alternative to animal and plant-based protein sources. It highlights the various yeast protein extraction methods including both mechanical and non-mechanical methods. The application of nanoparticles is one example of the fast-evolving technology used to damage microbial cells. SiO2 or Al2O3 nanoparticles break yeast cell walls and disrupt membranes, releasing intracellular bioactive compounds. Succinylation of yeast protein during extraction can increase yeast protein extraction rate, lower RNA concentration, raise yeast protein solubility, increase amino acid content, and improve yeast protein emulsification and foaming capabilities. Combining physical and enzymatic extraction methods generates the most representative pool of mannose proteins from yeast cell walls. Ethanol or isoelectric precipitation purifies mannose proteins. Mannoproteins can be used as foamy replacement for animal-derived components like egg whites due to their emulsification, stability, and foaming capabilities. Yeast bioactive peptide was separated by ultrafiltration after enzymatic hydrolysis of yeast protein and has shown hypoglycemic, hypotensive, and oxidative action in vitro studies. Additionally, the review delves into the physicochemical properties and stability of yeast-derived peptides as well as their applications in the food industry. The article infers that yeast proteins are among the promising sources of sustainable protein, with a wide range of potential applications in the food industry.

Lineage-specific gene duplication and expansion of DUF1216 gene family in Brassicaceae.

Proteins containing domain of unknown function (DUF) are prevalent in eukaryotic genome. The DUF1216 proteins possess a conserved DUF1216 domain resembling to the mediator protein of Arabidopsis RNA polymerase II transcriptional subunit-like protein. The DUF1216 family are specifically existed in Brassicaceae, however, no comprehensive evolutionary analysis of DUF1216 genes have been performed. We performed a first comprehensive genome-wide analysis of DUF1216 proteins in Brassicaceae. Totally 284 DUF1216 genes were identified in 27 Brassicaceae species and classified into four subfamilies on the basis of phylogenetic analysis. The analysis of gene structure and conserved motifs revealed that DUF1216 genes within the same subfamily exhibited similar intron/exon patterns and motif composition. The majority members of DUF1216 genes contain a signal peptide in the N-terminal, and the ninth position of the signal peptide in most DUF1216 is cysteine. Synteny analysis revealed that segmental duplication is a major mechanism for expanding of DUF1216 genes in Brassica oleracea, Brassica juncea, Brassica napus, Lepidium meyneii, and Brassica carinata, while in Arabidopsis thaliana and Capsella rubella, tandem duplication plays a major role in the expansion of the DUF1216 gene family. The analysis of Ka/Ks (non-synonymous substitution rate/synonymous substitution rate) ratios for DUF1216 paralogous indicated that most of gene pairs underwent purifying selection. DUF1216 genes displayed a specifically high expression in reproductive tissues in most Brassicaceae species, while its expression in Brassica juncea was specifically high in root. Our studies offered new insights into the phylogenetic relationships, gene structures and expressional patterns of DUF1216 members in Brassicaceae, which provides a foundation for future functional analysis.

Identification, Characterization, Cloning, and Cross-Reactivity of Zan b 2, a Novel Pepper Allergen of 11S Legumin.

Protein from Sichuan peppers can elicit mild to severe allergic reactions. However, little is known about their allergenic proteins. We aimed to isolate, identify, clone, and characterize Sichuan pepper allergens and to determine its allergenicity and cross-reactivities. Sichuan pepper seed proteins were extracted and then analyzed by SDS-PAGE. Western blotting was performed with sera from Sichuan pepper-allergic individuals. Proteins of interest were purified using hydrophobic interaction chromatography and gel filtration and further analyzed by analytical ultracentrifugation, circular dichroism spectroscopy, and mass spectrometry (MS). Their coding region was amplified in the genome. IgE reactivity and cross-reactivity of allergens were evaluated by dot blot, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot showed IgE binding to a 55 kDa protein. This protein was homologous to the citrus proteins and has high stability and a sheet structure. Four DNA sequences were cloned. Six patients' sera (60%) showed specific IgE reactivity to this purified 11S protein, which was proved to have cross-reactivation with extracts of cashew nuts, pistachios, and citrus seeds. A novel allergen in Sichuan pepper seeds, Zan b 2, which belongs to the 11S globulin family, was isolated and identified. Its cross-reactivity with cashew nuts, pistachios, and citrus seeds was demonstrated.

Potential relation between starch granule-associated proteins and retrogradation properties of buckwheat starch.

To elucidate the effect of starch granule-associated proteins (SGAPs) on retrogradation properties of buckwheat starch, the retrogradation properties of Tartary buckwheat starch (TBS) and common buckwheat starch (CBS) before and after removal of SGAPs were systematically investigated, with wheat starch (WS) as reference. A significant decrease in gel strength of starches and density of starch aggregates were observed after removing SGAPs. The results were in line with the changes in retrogradation enthalpy of starches and short-range ordered structure of starch aggregates. After removing SGAPs, the retrogradation enthalpy of TBS decreased from 4.16 J/g to 3.74 J/g, CBS decreased from 4.05 J/g to 3.35 J/g and WS decreased from 3.27 J/g to 2.81 J/g, respectively. Taken together the results of LF-NMR, FTIR and rheological analysis, it can be concluded that SGAPs could promote the hydrogen bond interactions between starch molecules by competitively binding with water molecules, enhancing the rearrangement of starch molecules and forming a more ordered structure. Overall, the study suggested that the presence of SGAPs could enhanced the interaction between starch molecules chains, thus accelerated the retrogradation process. The research results provide more information about SGAPs in buckwheat starch and support further study for manipulation of starch properties.

[Sweet protein brazzein as a promising sweetener].

The excessive consumption of sugar-containing foods contributes to the development of a number of diseases, including obesity, diabetes mellitus, etc. As a substitute for sugar, people with diabetes mellitus and obesity most often use sweeteners. Sweet proteins, in particular brazzein, are an alternative to synthetic sweeteners that have natural origin, are broken down in the intestines along with food proteins, and do not affect blood sugar and insulin levels. The purpose of the review was to analyze the available data on the sweet protein brazzein, its physical and chemical properties, existing biotechnological methods of production, and prospects for application in the food industry in order to further develop an optimized heterologous expression system. Material and methods. Google Scholar, Scopus, Web of Science, PubMed, RSCI and eLibrary.ru databases were used for collecting and analyzing literature. Search depth - 30 years. Results. Numerous studies of the physical and chemical properties of brazzein have demonstrated its high potential for use in the food industry. In particular, a short amino acid sequence, thermal stability, the ability to maintain its structure and sweet properties in a wide pH range, hypoallergenicity, lack of genotoxicity, and an extremely high level of sweetness compared to sucrose allow us to conclude that its use is promising. Mutant variants of brazzein have been generated, the sweetest of which (with three amino acid substitutions H31R/E36D/E41A) exceeds sucrose sweetness by 22 500 times. To date, various systems for the expression of recombinant brazzein have already been developed, in which bacteria (Escherichia coli, Lactococcus lactis, Bacillus licheniformis), yeast (Komagataella phaffii, Kluyveromyces lactis, Saccharomyces cerevisiae), plants (Zea mays, Oryza sativa, Lactuca sativa, Nicotiana tabacum, Daucus carota) and animals (Mus musculus) have been used. Conclusion. Due to its high sweetness, organoleptic properties and long history of human consumption, brazzein can be considered as a promising natural sweetener. Despite the short peptide sequence, the production of the recombinant protein faced a number of problems, including low protein yield (for example, it could only be detected in mouse milk by Western blot hybridization) and loss of sweetness. Thus, further optimization of the process is necessary for widespread brazzein use in the food industry, which includes the selection of an adequate producer and the use of extracellular expression systems to reduce the final cost of the product.

Biocontrol Potential of Sodin 5, Type 1 Ribosome-Inactivating Protein from Salsola soda L. Seeds.

Sodin 5 is a type 1 ribosome-inactivating protein isolated from the seeds of Salsola soda L., an edible halophytic plant that is widespread in southern Europe, close to the coast. This plant, known as 'agretti', is under consideration as a new potential crop on saline soils. Considering a possible defence role of sodin 5 in the plant, we report here its antifungal activity against different halophilic and halotolerant fungi. Our results show that sodin 5 at a concentration of 40 µg/mL (1.4 µM) was able to inhibit the growth of the fungi Trimmatostromma salinum (35.3%), Candida parapsilosis (24.4%), Rhodotorula mucilaginosa (18.2%), Aspergillus flavus (12.2%), and Aureobasidium melanogenum (9.1%). The inhibition observed after 72 h was concentration-dependent. On the other hand, very slight growth inhibition was observed in the fungus Hortaea werneckii (4.2%), which commonly inhabits salterns. In addition, sodin 5 showed a cytotoxic effect on the Sf9 insect cell line, decreasing the survival of these cells to 63% at 1.0 µg/mL (34.5 nM). Structural analysis of sodin 5 revealed that its N-terminal amino acid residue is blocked. Using mass spectrometry, sodin 5 was identified as a homologous to type 1 polynucleotide:adenosine glycosylases, commonly known as ribosome-inactivating proteins from the Amaranthaceae family. Twenty-three percent of its primary structure was determined, including the catalytic site.

Structure of the plant plastid-encoded RNA polymerase.

Chloroplast genes encoding photosynthesis-associated proteins are predominantly transcribed by the plastid-encoded RNA polymerase (PEP). PEP is a multi-subunit complex composed of plastid-encoded subunits similar to bacterial RNA polymerases (RNAPs) stably bound to a set of nuclear-encoded PEP-associated proteins (PAPs). PAPs are essential to PEP activity and chloroplast biogenesis, but their roles are poorly defined. Here, we present cryoelectron microscopy (cryo-EM) structures of native 21-subunit PEP and a PEP transcription elongation complex from white mustard (Sinapis alba). We identify that PAPs encase the core polymerase, forming extensive interactions that likely promote complex assembly and stability. During elongation, PAPs interact with DNA downstream of the transcription bubble and with the nascent mRNA. The models reveal details of the superoxide dismutase, lysine methyltransferase, thioredoxin, and amino acid ligase enzymes that are subunits of PEP. Collectively, these data provide a foundation for the mechanistic understanding of chloroplast transcription and its role in plant growth and adaptation.

Novel post-translationally cleaved Ara h 2 proteoforms: Purification, characterization and IgE-binding properties.

The 2S albumins Ara h 2 and Ara h 6 have been shown to be the most important source of allergenicity in peanut. Several isoforms of these allergens have been described. Using extraction and liquid chromatography we isolated proteins with homology to Ara h 2 and characterized hitherto unknown Ara h 2 proteoforms with additional post-translational cleavage. High-resolution mass spectrometry located the cleavage site on the non-structured loop of Ara h 2 while far UV CD spectroscopy showed a comparable structure to Ara h 2. The cleaved forms of Ara h 2 were present in genotypes of peanut commonly consumed. Importantly, we revealed that newly identified Ara h 2 cleaved proteoforms showed comparable IgE-binding using sera from 28 peanut-sensitized individuals, possessed almost the same IgE binding potency and are likely similarly allergenic as intact Ara h 2. This makes these newly identified forms relevant proteoforms of peanut allergen Ara h 2.

Substrate-induced condensation activates plant TIR domain proteins.

Plant nucleotide-binding leucine-rich repeat (NLR) immune receptors with an N-terminal Toll/interleukin-1 receptor (TIR) domain mediate recognition of strain-specific pathogen effectors, typically via their C-terminal ligand-sensing domains1. Effector binding enables TIR-encoded enzymatic activities that are required for TIR-NLR (TNL)-mediated immunity2,3. Many truncated TNL proteins lack effector-sensing domains but retain similar enzymatic and immune activities4,5. The mechanism underlying the activation of these TIR domain proteins remain unclear. Here we show that binding of the TIR substrates NAD+ and ATP induces phase separation of TIR domain proteins in vitro. A similar condensation occurs with a TIR domain protein expressed via its native promoter in response to pathogen inoculation in planta. The formation of TIR condensates is mediated by conserved self-association interfaces and a predicted intrinsically disordered loop region of TIRs. Mutations that disrupt TIR condensates impair the cell death activity of TIR domain proteins. Our data reveal phase separation as a mechanism for the activation of TIR domain proteins and provide insight into substrate-induced autonomous activation of TIR signalling to confer plant immunity.

Characteristics of ZjCIPKs and ZjbHLH74-ZjCIPK5 regulated cold tolerance in jujube.

CIPKs are kind of serine/threonine (Ser/Thr) protein kinases which play important roles in response to biotic and abiotic stresses, and in plant growth and development. However, CIPKs in jujube (Ziziphus jujuba Mill.) had limited information, especially regarding their response to cold stress. In the current study, a total of 18 ZjCIPKs were identified in jujube genome which unevenly distributed on seven chromosomes. Conserved motif and gene structural analysis depicted them with conserved DEGLSA and APE motifs and similar structures. Phylogenetic analysis indicated that CIPKs were classified into five subgroups (I-V). In addition, three pairs of ZjCIPKs exhibited tandem duplication while the segmental duplication of ZjCIPKs was not identified. Study on the cis-acting elements indicted that stress or hormone related cis-acting elements were distributed unevenly on ZjCIPKs promoters and most ZjCIPKs were down- or up-regulated by the cold stress. VIGS induced silencing of ZjCIPK5 decreased the cold tolerance of sour jujube. Subcellular location analysis showed ZjCIPK5 located in nucleus. Moreover, transcription factor ZjbHLH74 which was induced at 6 h under cold stress could interact with the promoter of ZjCIPK5 to regulate jujube cold tolerance. These findings provided insights to a molecular basis of CIPK5 in jujube cold tolerance breeding for future.

Comparative analysis of PLATZ transcription factors in six poplar species and analysis of the role of PtrPLATZ14 in leaf development.

Plant AT-rich sequence and zinc-binding (PLATZ) proteins are a class of plant-specific transcription factor that play a crucial role in plant growth, development, and stress response. However, the evolutionary relationship of the PLATZ gene family across the Populus genus and the biological functions of the PLATZ protein require further investigation. In this study, we identified 133 PLATZ genes from six Populus species belonging to four Populus sections. Synteny analysis of the PLATZ gene family indicated that whole genome duplication events contributed to the expansion of the PLATZ family. Among the nine paralogous pairs, the protein structure of PtrPLATZ14/18 pair exhibited significant differences with others. Through gene expression patterns and co-expression networks, we discovered divergent expression patterns and sub-networks, and found that the members of pair PtrPLATZ14/18 might play different roles in the regulation of macromolecule biosynthesis and modification. Furthermore, we found that PtrPLATZ14 regulates poplar leaf development by affecting cell size control genes PtrGRF/GIF and PtrTCP. In conclusion, our study provides a theoretical foundation for exploring the evolution relationships and functions of the PLATZ gene family within Populus species and provides insights into the function and potential mechanism of PtrPLATZ14 in leaf morphology that were diverse across the Populus genus.

Structure, evolution, and roles of SWEET proteins in growth and stress responses in plants.

Carbohydrates are exported by the SWEET family of transporters, which is a novel class of carriers that can transport sugars across cell membranes and facilitate sugar's long-distance transport from source to sink organs in plants. SWEETs play crucial roles in a wide range of physiologically important processes by regulating apoplastic and symplastic sugar concentrations. These processes include host-pathogen interactions, abiotic stress responses, and plant growth and development. In the present review, we (i) describe the structure and organization of SWEETs in the cell membrane, (ii) discuss the roles of SWEETs in sugar loading and unloading processes, (iii) identify the distinct functions of SWEETs in regulating plant growth and development including flower, fruit, and seed development, (iv) shed light on the importance of SWEETs in modulating abiotic stress resistance, and (v) describe the role of SWEET genes during plant-pathogen interaction. Finally, several perspectives regarding future investigations for improving the understanding of sugar-mediated plant defenses are proposed.

Mung bean protein isolate: Extraction, structure, physicochemical properties, modifications, and food applications.

The intake of plant-based proteins is rapidly growing around the world due to their nutritional and functional properties, as well as growing demand for vegetarian and vegan diets. Mung bean seeds have been traditionally consumed in Asian countries due to their unique botanical and health-promoting characteristics. In recent years, mung bean protein isolate (MBPI) has attracted much attention due to its ideal techno-functional features, such as water and oil absorption capacity, solubility, emulsifying, foaming, and thermal properties. Therefore, it can be utilized in a native or modified form in different food sectors, such as biodegradable/edible films, colloidal systems, and plant-based alternative products. This study provides a comprehensive review on the extraction methods, amino acid profile, structure, physicochemical properties, modifications, and food applications of MBPI.

The structure and potential allergenicity of peanut allergen monomers after roasting.

Given that roasted peanut (Ro) products are commonly used in daily life, peanut allergenicity is a foremost concern. Analyzing the changes in the structure and potential allergenicity of individual allergens can promote the exploration of the structural basis of the alterations in the potential allergenicity of Ro. This work focused on four major allergens in raw peanut (Ra) and Ro. Structural changes were analyzed on the basis of circular dichroism, ultraviolet and fluorescence spectroscopy, and molecular dynamic simulation. The IgE recognition capability of allergens was assessed via western blot analysis. The IgE binding capacity of allergens was detected by conducting enzyme-linked immunosorbent assay. The potential allergenicity of allergens was evaluated using the KU812 cell degranulation model. The results showed that roasting induced different changes in the overall structures of allergens and altered the structures and electrostatic potential of IgE epitopes, especially Ara h 1 and Ara h 6. These alterations affected the potential allergenicity of allergens. Ara h 1 and Ara h 6 in Ro showed significantly enhanced IgE binding capacities and abilities to elicit KU812 cell degranulation, while Ara h 2 and Ara h 3 did not change significantly. For total protein, the roasted peanut protein showed decreased abilities to elicit KU812 cell degranulation. The results indicated that different allergens in Ro showed different changes of structures and potential allergenicity and that the conformational structure plays a crucial role in potential allergenicity of allergens.

Mass Spectrometry Analysis on the Breakage of Allergens in High-Molecular-Mass Polymer of Roasted Peanuts.

Peanut allergy is a prevalent and concerning food allergy. Roasting can introduce structural changes to peanut allergens, affecting their allergenicity, but the structure on the primary structure is unclear. Here, the breakage sites were identified by mass spectrometry and software tools, and structural changes were simulated by molecular dynamics and displayed by PyMOL software. Results revealed that the appearance frequencies of L, Q, F, and E were high at the N-terminal of the breakage site, while S and E were dominant at the C-terminal. In the conformational structure, breakage sites were found close to disulfide bonds and the Cupin domains of Ara h 1 and Ara h 3. The breakage of allergens destroyed linear epitopes and might change the conformation of epitopes, which could influence peanuts' potential allergenicity.

Defining the cross-reactivity between peanut allergens Ara h 2 and Ara h 6 using monoclonal antibodies.

In peanut allergy, Arachis hypogaea 2 (Ara h 2) and Arachis hypogaea 6 (Ara h 6) are two clinically relevant peanut allergens with known structural and sequence homology and demonstrated cross-reactivity. We have previously utilized X-ray crystallography and epitope binning to define the epitopes on Ara h 2. We aimed to quantitatively characterize the cross-reactivity between Ara h 2 and Ara h 6 on a molecular level using human monoclonal antibodies (mAbs) and structural characterization of allergenic epitopes. We utilized mAbs cloned from Ara h 2 positive single B cells isolated from peanut-allergic, oral immunotherapy-treated patients to quantitatively analyze cross-reactivity between recombinant Ara h 2 (rAra h 2) and Ara h 6 (rAra h 6) proteins using biolayer interferometry and indirect inhibitory ELISA. Molecular dynamics simulations assessed time-dependent motions and interactions in the antibody-antigen complexes. Three epitopes-conformational epitopes 1.1 and 3, and the sequential epitope KRELRNL/KRELMNL-are conserved between Ara h 2 and Ara h 6, while two more conformational and three sequential epitopes are not. Overall, mAb affinity was significantly lower to rAra h 6 than it was to rAra h 2. This difference in affinity was primarily due to increased dissociation of the antibodies from rAra h 6, a phenomenon explained by the higher conformational flexibility of the Ara h 6-antibody complexes in comparison to Ara h 2-antibody complexes. Our results further elucidate the cross-reactivity of peanut 2S albumins on a molecular level and support the clinical immunodominance of Ara h 2.

Characteristics of meat flavoring prepared using hydrolyzed plant protein mix by three different heating processes.

Meat flavoring was prepared using mainly enzymatic hydrolysate of plant protein mix, VB1, cysteine, and glucose by three heating processes, including A (80 °C-140 min), B (two-stage, 80 °C-30 min/120 °C-30 min), and C (120 °C-40 min). The A-, B-, and C-heated samples exhibited the strongest fatty and weakest meaty, the strongest meaty and kokumi, and the strongest roasted and bitterness characteristics, respectively. PLS-DA for free amino acids with TAVs and that for SPME/GC-MS results with GC-O and OAVs, suggested three amino acids and eight flavor compounds contributed significantly in differentiating taste or aroma attributes of the three heated samples. Molecular weight distribution and degree of amino substitution suggested 1-5 kDa peptides contributed to kokumi taste. Overall, C- and A-heating exhibited the highest rates in Maillard reaction and lipid oxidation, respectively, while those of B heating were between these two heating processes and responsible for better flavor of meat flavoring.

Identification and expression analysis of SBP-Box-like (SPL) gene family disclose their contribution to abiotic stress and flower budding in pigeon pea (Cajanus cajan).

The SPL gene family (for Squamosa Promoter-binding like Proteins) represents specific transcription factors that have significant roles in abiotic stress tolerance, development and the growth processes of different plants, including initiation of the leaf, branching and development of shoot and fruits. The SPL gene family has been studied in different plant species; however, its role is not yet fully explored in pigeon pea (Cajanus cajan ). In the present study, 11 members of the CcSPL gene family were identified in C. cajan . The identified SPLs were classified into nine groups based on a phylogenetic analysis involving SPL protein sequences from C. cajan , Arabidopsis thaliana , Cicer arietinum , Glycine max , Phaseolus vulgaris , Vigna unguiculata and Arachis hypogaea . Further, the identification of gene structure, motif analysis, domain analysis and presence of cis -regulatory elements in the SPL family members were studied. Based on RNA-sequencing data, gene expression analysis was performed, revealing that CcSPL2.1, 3 and 13A were significantly upregulated for salt-tolerance and CcSPL14 and 15 were upregulated in a salt-susceptible cultivar. Real-time qPCR validation indicated that CcSPL3, 4, 6 and 13A were upregulated under salt stress conditions. Therefore, molecular docking was performed against the proteins of two highly expressed genes (CcSPL3 and CcSPL14 ) with three ligands: abscisic acid, gibberellic acid and indole-3-acetic acid. Afterward, their binding affinity was obtained and three-dimensional structures were predicted. In the future, our study may open avenues for harnessing CcSPL genes in pigeon pea for enhanced abiotic stress resistance and developmental traits.

Genome-wide identification, phylogeny and expression analysis of the R2R3-MYB gene family in quinoa (Chenopodium quinoa) under abiotic stress.

The MYB transcription factor (TF) are among the largest gene families of plants being responsible for several biological processes. The R2R3-MYB gene family are integral player regulating plant primary and secondary metabolism, growth and development, and responses to hormones and stresses. The phylogenetic analysis combined with gene structure analysis and motif determination resulted in division of R2R3-MYB gene family into 27 subgroups. Evidence generated from synteny analyses indicated that CqR2R3-MYBs gene family is featured by tandem and segmental duplication events. On the basis of RNA-Seq data, the expression patterns of different tissues under salt treatment were investigated resulting CqR2R3-MYB genes high expression both in roots and stem of quinoa (Chenopodium quinoa ) plants. More than half of CqR2R3-MYB genes showed expression under salt stress. Based on this result, CqR2R3-MYB s may regulate quinoa plant growth development and resistance to abiotic stresses. These findings provided comprehensive insights on role of CqR2R3-MYBs gene family members in quinoa and candidate MYB gene family members can be further studies on their role for abiotic stress tolerance in crop plants.

Comprehensive genomic exploration of class III peroxidase genes in guava unravels physiology, evolution, and postharvest storage responses.

Peroxidases (PRXs) play multifaceted roles in plant growth, development, and stress responses. Here, we present a comprehensive analysis of the PRX gene family in guava, a globally significant fruit. In the guava genome, we identified 37 PRX genes, a number lower than that of Arabidopsis, suggesting a distinctive gene family expansion pattern. Phylogenetic analysis unveiled close relationships with Arabidopsis PRXs, with 12 PgPRX genes forming ortholog pairs, indicating a specific expansion pattern. Predictions placed most PRX proteins in the chloroplast and extracellular regions. Structural analysis of PgPRX proteins revealed commonalities in domain structures and motif organization. Synteny analysis underscored the dynamic role of segmental duplication in the evolution of guava's PRX genes. We explored the dynamic expression of PgPRX genes across guava tissues, exposing functional diversity. Furthermore, we examined changes in peroxidase levels and gene expressions during postharvest fruit storage, providing insights for preserving fruit quality. This study offers an initial genome-wide identification and characterization of Class III peroxidases in guava, laying the foundation for future functional analyses.