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To investigate the variation in pepper quality across different regions, three pepper varieties (Jiao yang 6, La yan 101 and Zhuo jiao xin 52) were selected and planted in Guizhou, Yunnan, Chongqing, Shaanxi and Xinjian Provinces. In order to provide reference for the selection of pepper varieties in different regions, principal component analysis and cluster analysis were employed to evaluate the suitability of each pepper variety for its region by determining the peppers' nutritional quality, such as capsaicin, reducing sugar, amino acids, crude fibre, crude fat, capsaicin. The study revealed that significant variations presented in pepper quality across different producing areas and the coefficient of variation ranged from 5.79% to 50.29%. Among them, capsaicin content varied the most with origin. Notably, the average coefficient of variation was 41.94% for capsaicin and was about 8% for crude fiber and amino acids. The comprehensive evaluation of La yan 101 variety was the highest, then Zhuo jiao xin 52 was the second by principal component analysis. Meanwhile, all three varieties showed higher quality scores when planted in Guizhou Province compared to other four regions. In summary, peppers quality varied significantly among different regions and La yan 101 planted in Guizhou demonstrated the best quality performance. Thus we concluded that these peppers planted in Guizhou Province had quality advantages to other four provinces.

Abstract Background Pepper (Capsicum pubescens), one of five domesticated pepper species, has unique characteristics, such as numerous hairs on the epidermis of its leaves and stems, black seeds, and vibrant purple flowers. To date, no studies have reported on the complete assembly of the mitochondrial genome (mitogenome) of C. pubescens. Understanding the mitogenome is crucial for further research on C. pubescens. Results In our study, we successfully assembled the first mitogenome of C. pubescens, which was assigned the GenBank accession number OP957066. This mitogenome has a length of 454,165 bp and exhibits the typical circular structure observed in most mitogenomes. We annotated a total of 70 genes, including 35 protein-coding genes (PCGs), 30 tRNA genes, 3 rRNA genes, and 2 pseudogenes. Compared to the other three pepper mitogenomes (KJ865409, KJ865410, and MN196478), C. pubescens OP957066 exhibited four unique PCGs (atp4, atp8, mttB, and rps1), while two PCGs (rpl10 and rps3) were absent. Notably, each of the three pepper mitogenomes from C. annuum (KJ865409, KJ865410, and MN196478) experienced the loss of four PCGs (atp4, atp8, mttB, and rps1). To further explore the evolutionary relationships, we reconstructed a phylogenetic tree using the mitogenomes of C. pubescens and fourteen other species. Structural comparison and synteny analysis of the above four pepper mitogenomes revealed that C. pubescens shares high sequence similarity with KJ865409 and that C. pubescens has rearranged with the other three pepper mitogenomes. Interestingly, we observed 72 similar sequences between the mitochondrial and chloroplast genomes, which accounted for 12.60% of the mitogenome, with a total length of 57,207 bp. These sequences encompassed 12 tRNA genes and the rRNA gene (rrn18). Remarkably, selective pressure analysis suggested that the nad5 gene underwent obvious positive selection. Furthermore, a single-base mutation in three genes (nad1, nad2, and nad4) resulted in an amino acid change. Conclusion This study provides a high-quality mitogenome of pepper, providing valuable molecular data for future investigations into the exchange of genetic information between pepper organelle genomes.

In the environmental context of Türkiye, the quantity of organic matter present in the soil is a crucial factor that affects its productivity potential. While peat offers an optimal growth condition, it is an expensive material due to its limited availability globally, and in Türkiye. Hence, the research employed compost, which could be a viable replacement for peat, and is a sustainable, and independent alternative resource. The study examined the effects of 13 diverse growing media, both in pure, and mixed form, which included a control treatment of a 2:1 peat to perlite mixture, and three composts derived from grape, apple, and tomato pulps. The research investigated various growth criteria, such as seedling height, hypocotyl length, and diameter, number of leaves per seedling, root length, seedling dry weight, and root dry weight of tomato, cucumber, and pepper plants. The study indicated that grape compost, apple compost, tomato compost:peat:perlite (GAT:P:P), and grape compost:peat:perlite (G:P:P) were viable alternatives to the traditional peat/perlite mixture for tomato seedlings. Similarly, grape compost (G), apple compost (A), and apple compost:perlite (A:P) showed potential as substitutes for cucumber seedlings while apple compost (A) proved a possible option for chilli seedlings. In particular, the treatments using solely apple or grape composts, or a combination of both, exhibited superior performance in comparison to the control treatment.

Abstract Temperature is an important limiting factor in the counter-seasonal cultivation of pepper. Currently, there are no studies on transcriptomic analysis of ‘cold stress memory’ in pepper. In this study, in order to understand the mechanism of ‘cold stress memory’ in pepper (Capsicum annuum L.), seedlings were subjected to the following treatments: normal temperature treatment (P0), the first cold treatment for 3 days (P3), the recovery temperature treatment for 3 days (R3), and another cold treatment for 3 days (RP3). The results showed that P3 plants wilted the most, RP3 the second and R3 the least. Leaf reactive oxygen species (ROS) and electrolyte leakage were the most in P3, the second in RP3 and the least in R3. In addition, RP3 had the highest accumulation of zeaxanthin, violaxanthin and β-cryptoxanthin, followed by P3, and R3 had the least. These results suggest that pepper seedlings are characterized by ‘cold stress memory’. Transcriptomics was used to analyze the key genes and transcription factors involved in the biosynthesis of zeaxanthin, violaxanthin and β-cryptoxanthin during the formation of ‘cold stress memory’. This study provides candidate genes and transcription factors for an in-depth study of the cold tolerance mechanism in pepper.

Abstract [Objective] PEX (pollen extensin-like) gene is involved in controlling pollen development, which plays a crucial role in embryogenesis of pollen microspores and haploid culture. In this study, the authors isolated the CaPEX3 gene from pepper and analyzed its protein structure and expression pattern, which provides a theoretical foundation for further investigation into the function of the CaPEX3 gene. [Methods] CaPEX3 was cloned by PCR, and its protein structure, evolution, and gene regulation were analyzed by bioinformatics. Expression of CaPEX3 in different tissues and pollen of different varieties were detected by qRT-PCR. Pollen viability of different pepper varieties was detected by staining method and their relationship with CaPEX3 expression was analyzed. [Results] The coding region of CaPEX3 was 1 581 bp in length, encoding 526 amino acids, which belongs to the LRX (leucine-rich repeats/extensins) gene family. The protein had phosphorylation and glycosylation sites, signaling peptides, and transmembrane domains. The expression level of CaPEX3 was the highest in flowers, and the gene expression was higher in tissues with high pollen vitality. The regulatory network predicted that CaPEX3 might be involved in the regulation of pollen development through the action of genes related to flower development. [Conclusion] CaPEX3 was specifically expressed in flowers, and a correlation was observed between its expression level and the activity of pollen grains. The analysis of gene expression and the construction of related vectors provided a theoretical foundation and technical support for the subsequent investigation of gene function and mechanism of CaPEX3

Abstract Background The growth and yield of pepper, a typical temperature-loving vegetable, are limited by low-temperature environments. Using low-temperature sensitive ‘Hangjiao No. 4’ (Capsicum annuum L.) as experimental material, this study analyzed the changes in plant growth and photosynthesis under different treatments: normal control (NT), low-temperature stress alone (LT), low-temperature stress in strigolactone pretreated plants (SL_LT), and low-temperature stress in strigolactone biosynthesis inhibitor pretreated plants (Tis_LT). Results SL pretreatment increased the net photosynthetic rate (Pn) and PSII actual photochemical efficiency (φPSII), reducing the inhibition of LT on the growth of pepper by 17.44% (dry weight of shoot). Due to promoting the accumulation of carotenoids, such as lutein, and the de-epoxidation of the xanthophyll cycle [(Z + A)/(Z + A + V)] by strigolactone after long-term low-temperature stress (120 h), non-photochemical quenching (NPQ) of pepper was increased to reduce the excess excitation energy [(1-qP)/NPQ] and the photoinhibition degree (Fv/Fm) of pepper seedlings under long-term low-temperature stress was alleviated. Twelve cDNA libraries were constructed from pepper leaves by transcriptome sequencing. There were 8776 differentially expressed genes (DEGs), including 4473 (51.0%) upregulated and 4303 (49.0%) downregulated genes. Gene ontology pathway annotation showed that based on LT, the DEGs of SL_LT and Tis_LT were significantly enriched in the cellular component, which is mainly related to the photosystem and thylakoids. Further analysis of the porphyrin and chlorophyll biosynthesis, carotenoid biosynthesis, photosynthesis-antenna protein, and photosynthetic metabolic pathways and the Calvin cycle under low-temperature stress highlighted 18, 15, 21, 29, and 31 DEGs for further study, which were almost all highly expressed under SL_LT treatment and moderately expressed under LT treatment, whereas Tis_LT showed low expression. Conclusion The positive regulatory effect of SLs on the low-temperature tolerance of pepper seedlings was confirmed. This study provided new insights for the development of temperature-tolerant pepper lines through breeding programs.

To address growing concerns about sustainable agriculture and waste management, this study aimed to explore the viability of tea waste as an eco-friendly alternative substrate for cultivating Charleston peppers (Capsicum annuum), with the goal of optimizing plant growth and yield while reducing soil dependence, lowering cultivation costs, and repurposing agro-industrial waste. Six different substrate combinations were evaluated: 1) Tea waste, 2) Tea waste + Manure, 3) Tea waste + Soil, 4) Manure + Soil, 5) Tea waste + Manure + Soil, and 6) Tea waste + Manure + Soil + Perlite. Data were analyzed using both multivariate and univariate analyses to assess significant differences among treatments. Notably, significant differences in stem diameter were observed among plants grown on different substrates (one-way MANOVA, p

Abstract Background The WD40 domain, one of the most abundant in eukaryotic genomes, is widely involved in plant growth and development, secondary metabolic biosynthesis, and mediating responses to biotic and abiotic stresses. WD40 repeat (WD40) protein has been systematically studied in several model plants but has not been reported in the Capsicum annuum (pepper) genome. Results Herein, 269, 237, and 257 CaWD40 genes were identified in the Zunla, CM334, and Zhangshugang genomes, respectively. CaWD40 sequences from the Zunla genome were selected for subsequent analysis, including chromosomal localization, phylogenetic relationships, sequence characteristics, motif compositions, and expression profiling. CaWD40 proteins were unevenly distributed on 12 chromosomes, encompassing 19 tandem duplicate gene pairs. The 269 CaWD40s were divided into six main branches (A to F) with 17 different types of domain distribution. The CaWD40 gene family exhibited diverse expression patterns, and several genes were specifically expressed in flowers and seeds. Yeast two-hybrid (Y2H) and dual-luciferase assay indicated that CaWD40-91 could interact with CaAN1 and CaDYT1, suggesting its involvement in anthocyanin biosynthesis and male sterility in pepper. Conclusions In summary, we systematically characterized the phylogeny, classification, structure, and expression of the CaWD40 gene family in pepper. Our findings provide a valuable foundation for further functional investigations on WD40 genes in pepper.

The escalating global population, diminishing agricultural lands, and the overarching global climate crisis are significantly impacting pepper cultivation. These challenges exacerbate the vulnerability of pepper plants to various biotic and abiotic factors, particularly viral diseases, resulting in diminished yield and quality. Cucumber mosaic virus (CMV), a notable concern for peppers in the Solanaceae family, is causing substantial quality and yield losses, with no effective chemical control methods currently available. This study focuses on exploring the genetic structure of CMV isolates obtained from pepper production areas in Kilis province and comparing these regions through the High-Resolution Melting (HRM) method. CMV isolates, cultivated in tobacco plants, have their partial coat protein sequences compared with those of other CMV isolates registered in the gene bank. The nucleotide sequences of identified CMV isolates are phylogenetically grouped and compared using an HRM graph. The HRM graph effectively distinguishes Kilis 3 and Kilis 4 isolates, clustered similarly to sequence patterns, from other isolates. The study highlights the utility of HRM analyses in identifying differences between isolates before determining sequence patterns. In the gene bank comparison, Kilis CMV isolates distinguished from others. Similarities were observed with isolates from Iran's Balsam (Impatiens balsamina - LC066478), Türkiye's Radish (Raphanus sativus - LC0665051), and Wild Turnip (Rapistrum rugosum - LC066514, LC066511, LC066517). The study found that Kilis 7 CMV isolate, transferred mechanically to 24 different pepper genotypes (C. annuum) from the local population, revealed susceptibility to CMV in the 24 lines developed from the Elbeyli population in Kilis province.

Abstract [Objective] The study aims to explore the expression and function of the RIN gene, encoding a MADS-box, and analyze its impact on the metabolism of carotenoids in pepper. [Methods] Based on the fruit development transcriptome of pepper, the full-length CDS of the MADS-box transcription factor Ca- RIN gene related to chili ripening was cloned. The bioinformatics, expression pattern, subcellular localization, and transcriptional activation activity were examined, and the effects of VIGS-induced CaRIN gene silencing on carotenoid metabolism were investigated. [Results] (1) The CDS of CaRIN gene was 732 bp in length. CaRIN gene encoded a protein containing 243 amino acids with a molecular mass of 27.95 kD and an isoelectric point (pI) of 7.06. CaRIN protein had a typical MEF2_ like MADS domain, belonging to the MICK type transcription factor. (2) CaRIN gene was mainly expressed in flowers and fruits with tissue specificity. CaRIN was located in the nucleus and had transcriptional activation activity. (3) The promoter of CaRIN gene had several hormone response elements such as ABRE, and exogenous ABA and ethephon accelerated the fruit to turn red and induced the high expression of CaRIN and related genes. (4) After VIGS-induced gene silencing of CaRIN , the expression level of PSY1, CCS, PDS, CRTZ, LCYB, and NCED1, genes involved in carotenoid metabolic pathway, was decreased by 0.27-0.59 times, and the total carotenoid content in fruits (0.379 mg/g) was decreased compared with the control (0.650 mg/g). [Conclusion] CaRIN may be an important regulatory factor of carotenoid metabolism in capsicum fruits.

Pepper is one of the important vegetable crops and condiments in China. Carrying out researches on pepper genomics is of great significance for understanding the genetics and evolution of peppers, tapping important functional genes of peppers, and using biotechnology to conduct genetic improvement of varieties. The release of the draft pepper genomic map in 2014 marked the entry of pepper into an era of genomics research. Over the past decade, remarkable progress has been made in pepper genomics research, revealing the basic features of pepper genome deeply and constructing a preliminary pan-genome of pepper. Meanwhile, pepper genomics has been widely applied in exploring the interspecific differentiation and gene introgression of pepper, analyzing the evolutionary mechanism of pepper important traits, elucidating the genetic diversity of pepper, revealing the characteristics of artificial domestication of pepper, tracing the history of global range expansion and dissemination of pepper, and exploring the genes controlling the formation of important traits of pepper and so on. In this paper, we review and summarize the progress made in pepper genomics and its applications over the past 10 years, and look forward to the construction of a higher-quality pepper reference genome and pan-genome as well as the improvement of the research platform for pepper functional genomics, with an aim to provide a reference for pepper genomics and related applications.

【Objective】The study was carried out to explore the distribution patterns of rhizospheric microbial communities in different resistant pepper varieties, aiming to provide a basis for the targeted optimization of rhizospheric microbial community structure of pepper.【Method】Taking the susceptible pepper variety 'Hailan 99' (HL99) and the resistant variety 'Sanxiaqing' (SSQ) as experimental materials, high-throughput sequencing technology was employed to analyze and compare the effects of susceptible and non-susceptible soil environments on the community diversity, species composition, correlation networks and function of bacteria and fungi in the rhizosphere soil of different disease-resistant pepper plants.【Result】Through high-throughput sequencing, a total of 66 617 operational taxonomic units (OTUs) from soil bacterial samples were obtained, among which the dominant phyla were Proteobacteria and Bacteroidetes, with the relative abundances of approximately 40.1% and 15.3%, respectively. From soil fungal samples, 2 948 OTUs were obtained, among which the dominant phylum was Ascomycota, with an average relative abundance of approximately 47.8%. The rhizospheric microbial community structure and species composition of pepper varieties showed significant differences under different soil conditions. Under susceptible soil conditions, the diversity of bacterial communities in pepper rhizosphere decreased, while the diversity of fungal communities increased. The bacterial OTUs decreased by 6.5%-7.8%, and fungal OTUs increased by 8.8%-9.8%. The relative abundance of Fusarium fungi was significantly higher in the susceptible group (5.0%) compared with that in the resistant group (4.8%), while the relative abundance of beneficial fungi like Mortierella and Trichoderma and beneficial bacteria like Pseudomonas and Bacillus was significantly lower in the susceptible group than that in the resistant group. Overall, under the susceptible soil conditions, the abundance of beneficial rhizosphere fungi and bacteria in the resistant group was higher than that in the susceptible group, contributing to a better soil micro-ecological environment. Based on species abundance tables, the correlation relationships of fungi-fungi, fungi-bacteria and bacteria-bacteria species were calculated respectively at the genus level. The results indicated that the rhizosphere microorganisms of pepper formed a complex ecological network, with high co-occurrence between fungi-fungi and fungi-bacteria (with a positive correlation percentage higher than 50%), suggesting that cooperative relationships outweighed competitive ones. The bacteria-bacteria network structure was more complex, with a positive correlation percentage of about 49.9%.【Conclusion】The rhizospheric microbial community structures of different resistant varieties exhibit significant differences under different soil conditions. The interaction of rhizosphere microorganisms forms a complex microbial ecological network structure. The relative abundance of beneficial fungi and bacteria is higher in the resistant variety than that in the susceptible variety, which suppresses more pathogenic microbes, leading to a healthier soil micro-ecological environment. The key groups identified in this study, including Fusarium, Verticillium, Trichoderma, Bacillus and Pseudomonas, will provide important information for the targeted optimization of rhizospheric microbial community structures and offer crucial theoretical references for the biological control of soil-borne diseases.

Background Pepper from Capsicum species is a well-established spice with a rich history of culinary use. Some observations have linked its consumption to gastrointestinal discomfort and alterations in stool patterns while it is considered beneficial in some cultures. However, there is lack of information on the direct effect of pepper consumption on human gut microbiota, we conducted dietary intervention studies to assess the impact of pepper on gut bacteriome composition in humans. Methods Ten healthy volunteers were recruited, and each person received 200 ml of 0.14 g/ml fresh Habanero Pepper (Capsicum chinense) daily over a 4-day period after which they abstained from pepper consumption for the subsequent 4 days before resumption of their normal diet. Stool samples were collected at baseline, after pepper consumption, after 4 days without pepper and after 4- and 6-days resumption of normal diet. We sequenced the V3-V4 region of the 16S rRNA gene and analyzed microbial diversity and composition using the QIIME2 pipeline and relevant R packages. Results Consumption of pepper over a 4-day period led to a higher abundance of Verrucomicrobia, a phylum rarely found in significant proportions at other time points. There was a gradual depletion of Shigella and Staphylococcus spp. from baseline untill the end of the study. Other taxa showed timepoint specific associations, emphasizing the potential impact of short-term dietary interventions on the relative abundance of these genera. Conclusions Our study adds nuance to the understanding of diet-microbiota interactions, highlighting the intricate relationship between pepper consumption and gut bacteriome composition. Further exploration of these dynamics holds promise for personalized dietary recommendations and targeted interventions to support gut microbial health.

Pepper (Capsicum spp.) is highly popular due to its unique flavor. However, there was limited research on the primary volatiles that influence the different flavors of fresh peppers. In this study, peppers with three aroma compound types denoted as “grassy,” “fruity,” and “no special aroma” (control) were analyzed using sensory evaluation combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). Altogether, 393 volatiles were identified by GC–MS, and the main volatiles in peppers (C. chinense Jacq.) were esters and terpenoids. GC–O and relative odor activity value analysis revealed that 2-isobutyl-3-methoxypyrazine had a highly bitter, spicy aroma intensity in all peppers. Hexanal and trans-2-hexenal were the main aroma-active compounds in grassy peppers. In addition, citronellal was determined to be a crucial aroma-active compound in fruity peppers. This study offers a theoretical foundation for guiding the growth of the pepper processing industry and breeding.

To construct pepper development simulation models under drought, experiments of water capacities of 45–55%, 55–65%, 65–75% or 75–85% and exposure (2, 4, 6 or 8 d) (Exp. 1 & 2), of 50–60%, 60–70% or 70–80% and exposure (3, 5, and 7 d) (Exp. 3) were conducted with “Sanying” pepper. Physiological development time (PDT), product of thermal effectiveness and PAR (photosynthetically active radiation) (TEP) and growing degree days (GDD) were used to simulate growth under various treatments in Exp. 1. Plant development was influenced by the severity and drought duration. Mild water deficits (65–75% for 2–6 d or 55–65% for 2–4 d) accelerated development, while severe water deficits (65–75% for 8 d, 55–65% for 6–8 d or 45–55% for 2–8 d) delayed development. The PDT gave the highest coefficient of determination (R2, 0.89–0.94) and the lowest root mean squared error (RMSE, average of 1.03–1.50 d) and relative error (RE, average of 1.60–1.88%) for simulating three growth periods (Exp. 2). It was therefore used to construct growth models under water capacity of 45–85% over 2–8 d with spline, cubic, makima, linear, and nearest interpolation. Validation in Exp. 3 indicated that the spline model was optimal, having the highest R2 (0.96–0.97) and the lowest RMSE (average of 1.31–1.75 d) and RE (average of 1.18–2.06%). The results of the study can help producers to optimize water management and to develop drought strategies for production.

This study compared the total phenolic content, antioxidant activity, and antimicrobial activity of ripe and unripe Ghanaian habanero pepper (Capsicum chinense) against some selected foodborne pathogens. The total phenolic content (TPC) of the pepper extracts was determined using the Folin-Ciocalteu method, while the radical scavenging potential of the pepper extracts was assessed using the DPPH and ABTS assays. Determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), combinatory effects with standard antimicrobial agents, and inhibition of biofilm formation were used to assess the antimicrobial activity of the pepper extracts. The results showed that the ripe pepper extract outperformed the unripe pepper extract in terms of TPC and radical scavenging potential. The TPC values of 1004.52 µgGAE/g and 1362.79 µgGAE/g were obtained for unripe pepper and ripe pepper extract, respectively. DPPH and ABTS free radical scavenging potential were 28.80 % and 91.32 % for unripe extracts and 34.27 % and 92.96 % for ripe pepper extract. In addition, varying degrees of MIC and MBC were obtained for both the unripe and ripe pepper extracts against test organisms. Combinatory effects with antimicrobial agents and antibiofilm formation activity varied for both pepper extracts. In conclusion, the use of pepper in food preparation could help reduce the menace of foodborne diseases.

Pepper is a key agricultural crop susceptible to accumulating heavy metals like cadmium (Cd) and barium (Ba), posing significant health risks. To address these issues, this study investigated the effects of foliar applications of fulvic acid (FA), Zn-fulvic acid (Zn-FA), and Fe-fulvic acid (Fe-FA) on Ba and Cd uptake in pepper tissues, as well as their impact on nutritional quality, biomass, and leaf enzyme activity. Results indicated that Fe-FA application significantly reduced Cd and Ba in pepper fruit by 25 % and 93 %, respectively. Additionally, Fe-FA enhanced pepper growth, increasing vitamin C and phenolic compounds by 136 % and 13 %, respectively. Metabolomics analysis revealed that Fe-FA application up-regulated 857 metabolites and down-regulated 1045 metabolites. Furthermore, Fe-FA primarily influenced amino acid, carbohydrate, and lipid metabolism, promoting pepper growth. These findings suggest that Fe-FA foliar application offers a promising strategy for reducing Ba and Cd accumulation in pepper fruits while enhancing its nutritional quality.

Fruit colour is a crucial factor influencing both the marketability and quality of pepper (Capsicum annuum), particularly ornamental varieties. Fruit colour is a complex multigenic trait in plant species. Previously, the Arabidopsis pseudo-response regulator 2 (APRR2) gene, one of the regulators that control fruit chlorophyll content and chloroplast development, thereby influencing fruit colour at the green immature stage in tomato (Solanum lycopersicum), cucumber (Cucumis sativus) and pepper, was reported. Functional molecular markers associated with this homologous gene in pepper could be employed to discern fruit colour at the seedling stage, thus improving the efficiency of green/white-fruited pepper breeding. In this study, a derived cleaved amplified polymorphic sequences (dCAPS) marker was developed based on the mutation site in the sequence of a CaAPRR2-like gene that was cloned from the inbred line B1-2, which exhibits milky white fruit at the green immature stage. The marker was subsequently validated in a CaAPRR2-like progeny segregation population. After digestion with the restriction endonuclease TaqI, the amplification product exhibited evident polymorphic bands, enabling it to distinguish between peppers with milky white and green fruit colours. The developed molecular marker displayed remarkable stability and repeatability, thus offering a straightforward and effective tool for enhancing fruit colour in pepper breeding programs.

Pepper is an important source of income for Ethiopian smallholder farmers. However, Fusarium wilt has been hindering pepper production and productivity. This study characterized the morphological variability of Fusarium oxysporum f. sp. capsici isolates collected from potential pepper production areas of West Gojjam, Ethiopia. A total of 196 symptomatic plant samples were collected and screened. Based on the macroscopic and microscopic characteristics, 67 F. oxysporum f. sp. capsici isolates were characterized. The distribution of F. oxysporum varied among districts, of which the largest number of the Fusarium isolates was recorded in Womberma (36%) and the lowest was in Burie Zuria (15%). The frequency of F. oxysporum occurrence varied in different plant parts including, roots (56.2%), stem (31.7%), and leaf (12.1%). Colony color varied from white (43.28%) to pink (10.45%). The radial growth of the colony varied from 2.5 – 4.5 cm on the 7th day of culture, of which, 6 isolates had >3 cm, 37 isolates had 3-4 cm, and 24 isolates had >4 cm radial growth. Two types of shapes were recorded with almost similar proportions (50.75% filamentous and 49.25% round). From the total 67 identified isolates, 74.6% had adherent mycelial and 26.4% of them had fluffy growth pattern. Microscopically, all the isolates produced micro- and macro-conidia. The microconidia had oval (67.16%), kidney (29.85%), and globose (2.99%) shaped morphology. The macroconidia were with curved (25) and straight (42) shaped morphology, with three to five septa. The isolates had an entire (73%) and filiform margin (27%). Further, pathogenicity and molecular characterization needs to be conducted.

Fungi are the prominent phytopathogens that have significant impact on the productivity of agriculture worldwide. Streptomyces species have been extensively studied for the production of various bioactive metabolites. These metabolites have been used as biocontrol agents for the management of diseases caused by phytopathogenic fungi. The purpose of this investigation is to assess the efficacy of Streptomyces sporoverrucosus B-1662, an antagonistic agent in the control of red pepper anthracnose caused by Colletotrichum acutatum KACC 42403 and apple anthracnose caused by Colletotrichum siamense CGCP6 (GYUN-10348). On the basis of the morphological, and molecular characterization using 16S rRNA, the strain B-1662 was determined to be S. sporoverrucosus. The strain B-1662 exhibited antagonistic activity against seven fungal phytopathogens, including C. acutatum KACC 42403 and C. siamense CGCP6. The culture filtrates (CF) from B-1662 showed antifungal activity against all seven fungal pathogens with greater inhibition rate (%) in comparison with a control. The bacterial suspensions of B-1662 showed an excellent biological control effect on the red pepper anthracnose and apple bitter rot using an in planta assay. The anthracnose disease rate (%) was controlled by over 90% with B-1662 cell suspensions at 105 to 107 CFU/mL. Compared to a control, the strain B-1662 played a more effective role in controlling the anthracnose disease in field conditions in both years 2022 and 2023. From the effective solvent fractions, the effect compound (dibutoxybutane) has been isolated exhibiting with antifungal effect. The genetic base underlying the biocontrol traits of B-1662 was characterized using the whole-genome sequence of B-1662, which was compared with closely related strains. Consequently, these results collectively suggest that S. sporoverrucosus B-1662 can aid in the management of red-pepper anthracnose.

Abstract Genetic analyses through molecular markers always depend on efficient protocols for DNA extraction and standardized PCR conditions. Random Amplified Polymorphic DNA (RAPD) is an inexpensive protocol that can provide information about the genetic diversity among Capsicum accessions within a germplasm bank, but it is highly sensitive to reaction conditions and manipulation. This work presents an optimized protocol for DNA isolation from dry Capsicum seeds, and a standardization of five conditions for PCR using RAPD primers. The RAPD protocol was optimized for the following parameters: 50 ng of DNA template per mix, 2.5 mM MgCl2, 200 µM dNTP's, 25 ng of primer per mix, and 45 thermal cycles, resulting in reproducible and clear amplified fragments. Good quality products were presented in the extractions and amplifications carried out; therefore, the optimized protocols are sufficient to be used in future work with RAPD.

Fruit color is an important qualitative trait that greatly influences the marketability of peppers. Fruit color can be divided into two categories. Green fruit color denotes commercial maturity, whereas ripe fruit indicates physiological maturity. Herein, segregation populations were created using the ‘D24’ with pale green in the green fruit stage, orange in the mature fruit stage, and ‘D47’ with green in the green fruit stage and red in the mature fruit stage. BSA-seq and genetic linkage map analysis revealed green fruit color was linked to (gyqtl1.1) on Chr1 and (gyqtl10.1) on Chr10, while mature fruit color was linked to Chr6. Using functional annotation, sequence, and expression analysis, we speculate that an SNP mutation in the CapGLK2 gene at the gyqtl10.1 interval could initiate premature termination of translation, thus yielding green to pale green fruits in D47. Conversely, the orange color in mature D24 fruits is due to the Indel-mediated premature termination of translation of the CapCCS gene. Our research offers a theoretical foundation for choosing different varieties of pepper fruit based on their color.

Foot rot disease (Phytophthora capsica) is Indonesia's primary challenge in cultivating pepper (Piper nigrum). Grafting to another Piper species, Piper coclobrinum, or melada (the local name), is a potential solution to increase resistance to this disease. The use of melada as rootstock has shown promising results during the seedling phase, but it has not been thoroughly evaluated during the production phase. The study was conducted in the pepper grower’s location in Puput and Simpang Katis Villages, Central Bangka, Bangka Belitung Islands Province. The study used kapok (Ceiba petandra) as the standard; plant morphology, leaf area, leaf thickness, and crown diameter for grafted melada and non-grafted pepper were recorded. Harvest variables included panicle length, panicle weight, the number of fruits per panicle, and fruit diameter, measured in three different areas of the canopy: the lower area (0-1 meter above the ground surface), the middle area (1-2 meters above the ground surface), and the top area (more than 2 meters above the ground surface). Physiological variables measured included rates of photosynthesis, stomatal conductance, transpiration rate, intercellular CO2, and CO2 conductance. The study demonstrated that the grafted pepper plants had a larger leaf area than the non-grafted pepper plants; the panicle weight and the number of fruits per panicle were higher. Panicles located in the middle zone of the plant canopy tended to be longer for grafted and non-grafted peppers. Panicle weight, fruit size, and the number of fruits per panicle were generally more significant at the top of the plant canopy. In all parts of the canopy, grafted peppers exhibited larger fruit size, greater panicle weight, and a higher number of fruits per panicle than non-grafted “Nyelungkup” peppers, highlighting the potential of melada as a rootstock for pepper plants.

The study explores the potential of incorporating pepper waste as a reinforcement material in aluminium AA6063 composites, with focussing on the morphological, mechanical, electrochemical, and optoelectric properties. Pepper wastes, including stalks and seeds, were carbonised, pulverized, and sieved to yield 75 μm particulates. These were mixed with molten AA6063 alloy via stir casting, with the pepper content ranging from 0% to 25% by weight. The composites were characterised using hardness testing, electrochemical evaluation, optoelectrical analysis, and morphological analysis. Hardness tests revealed that the 25% pepper-reinforced sample exhibited the highest hardness value of 37 HRB, a 31.7% increase over the control sample. Electrochemical evaluations showed significant improvements in corrosion resistance, with the corrosion potential (Ecorr) of the 25% pepper-reinforced sample reducing to −0.59 V and the corrosion rate decreasing to 7.69 mm/yr. Optoelectrical testing indicated enhanced conductivity in samples with higher pepper content, with the 25% reinforcement achieving a conductivity of 0.1979 (Ωm)⁻1. Morphological tests, such as SEM and XRD, revealed the uniform distribution of pepper particles and the occurrence of several phases that contribute to the composite's improved properties.

Red pepper (Capsicum annuum var. conoides) is commonly used for dried pepper production in China, and the drying process, particularly the during duration, profoundly affects its quality. The findings indicate that prolonged exposure to high temperatures during thermal drying results in significant darkening, an evident decrease in red and yellow tones, and gradual transformation of the pepper's microscopic structure from granular to compact, along with 88% reduction in moisture content and 81% decrease in thickness. The capsaicinoid content increased, resulting in a 4.3-fold increase in spiciness after drying compared to that of fresh pepper. The pepper aroma shifts from fruity, choking, and grassy to herb, dry wood, and smoky. Compounds such as 2-Acetylfuran, furfural, 2-methylfuran, 1-methylpyrrole, 2-methylpyrazine, and 2,5-dimethylpyrazine exhibited positive correlations with drying time, whereas ethyl 2-methylpropanoate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl hexanoate, and 3-methylbutyl butanoate showed negative correlations, indicating their potential as markers for monitoring thermal drying processes.

【Objective】As one of the four major nutrients required by plants, sulfur is a crucial for plant growth and development, playing a pivotal role in enhancing plant resistance against both biotic and abiotic stresses. Sulfate transporters (SULTR) serve as primary regulators in the absorption and transport of sulfate in plants, playing an irreplaceable role in this process. The understanding of the fundamental characteristics and expression patterns of CaSULTR genes could help to provide theoretical support for advancing researches on SULTR in peppers.【Method】Based on the pepper genome, members of the epper CaSULTR gene family were identified at the whole-genome level. A comprehensive analysis of their physicochemical properties, conserved Motifs and gene structures was conducted. By utilizing publicly available transcriptome data and qPCR technology, the expression patterns of CaSULTR genes under various hormone stress conditions were analyzed. Additionally, differentially expressed genes were cloned for further investigation.【Result】A total of 13 CaSULTR genes were identified and designated as CaSULTR1;1~1;3, CaSULTR2;1~2;2, CaSULTR3;1~3;7 and CaSULTR4;1. These genes were distributed on seven chromosomes in pepper, with amino acid lengths ranging from 641 to 947 aa, molecular weights from 69.65 to 104.36 kD, and isoelectric points between 8.42 to 9.62. Characterized by the hydrophobicity, CaSULTR proteins were classified into four subgroups (Ⅰ-Ⅳ), with subgroup Ⅲ containing the highest number of members. Within the same subgroup, members exhibited relatively small differences in physicochemical properties, and Motifs and gene structures were relatively conserved. With the exception of CaSULTR2;1 and CaSULTR2;2, all members possessed Motif 5. Tissue expression analysis indicated that CaSULTR genes may be involved in the development of organs such as leaves, fruits and flowers, with CaSULTR4;1 exhibiting expression in leaves, roots and stems. Expression profile analysis under hormone stress, coupled with qPCR results, revealed significant up-regulation of CaSULTR1;1 and CaSULTR3;4 under hormone induction.【Conclusion】The expression patterns of CaSULTR genes under hormone stress are identified, suggesting that of CaSULTR1;1 and CaSULTR3;4 may be involved in the regulation of sulfur metabolism by exogenous hormones.

Abstract Pepper agronomic traits serve as pivotal indicators for characterizing germplasm attributes and correlations. It is important to study differential genotypic variation through phenotypic differences of target traits. Whole genome resequencing was used to sequence the whole genome among different individuals of species with known reference genomes and annotations, and based on this, differential analyses of individuals or populations were carried out to identify SNPs for agronomic traits related to pepper. This study conducted a genome-wide association study encompassing 26 key agronomic traits in 182 upward-growing fruits of C. frutescens and C. annuum. The population structure (phylogenetics, population structure, population principal component analysis, genetic relationship) and linkage disequilibrium analysis were realized to ensure the accuracy and reliability of GWAS results, and the optimal statistical model was determined. A total of 929 SNPs significantly associated with 26 agronomic traits, were identified, alongside the detection of 519 candidate genes within 100 kb region adjacent to these SNPs. Additionally, through gene annotation and expression pattern scrutiny, genes such as GAUT1, COP10, and DDB1 correlated with fruit traits in Capsicum frutescens and Capsicum annuum were validated via qRT-PCR. In the CH20 (Capsicum annuum) and YB-4 (Capsicum frutescens) cultivars, GAUT1 and COP10 were cloned with cDNA lengths of 1065 bp and 561 bp, respectively, exhibiting only a small number of single nucleotide variations and nucleotide deletions. This validation provides a robust reference for molecular marker-assisted breeding of pepper agronomic traits, offering both genetic resources and theoretical foundations for future endeavors in molecular marker-assisted breeding for pepper.

Yi Zhang,1,2,* Zhang-Rui Liang,1,3,* Yang Xiao,4 Yi-Shi Li,4 Bin-Jie Fu,1 Zhi-Gang Chu1 1Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China; 2Department of Radiology, Chongqing Jiangjin Second People’s Hospital, Chongqing Jiangjin Cancer Hospital, Chongqing, 402260, People’s Republic of China; 3Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, People’s Republic of China; 4Department of Respiratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China*These authors contributed equally to this workCorrespondence: Bin-Jie Fu; Zhi-Gang Chu, Department of Radiology, The First Affiliated Hospital of Chongqing Medical, University, 1# Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, People’s Republic of China, Tel +86 18883851162 ; +86 18723032809, Fax +86 23 68811487, Email binjie_fu@163.com; chuzg0815@163.comPurpose: To explore the computed tomography (CT) features of bronchopneumonia caused by pepper aspiration to improve the diagnosis.Materials and Methods: 28 adult patients diagnosed with obstructive pneumonia caused by pepper aspiration from January 2016 to September 2022 were enrolled. The CT characteristics of bronchial changes and pulmonary lesions caused by pepper were analyzed and summarized.Results: Among 28 patients, the most common symptom was cough (26, 92.9%), followed by expectoration (23, 82.1%). Bronchoscopy revealed that peppers were mainly found in the bronchus of the right lower lobe (n = 18, 64.3%), followed by the bronchus of the left lower lobe (n = 5, 17.9%). In combination with bronchoscopy results, the pepper in the bronchus manifested as circular or V/U-shaped high-density, localized soft tissue, and flocculent opacification in 8 (28.6%), 16 (57.1%), and 3 (10.7%) cases on CT images, respectively. The bronchial wall around the pepper was thickened with localized occlusion (n = 19, 67.9%) and stenosis (n = 9, 32.1%). Regarding adjacent bronchi without peppers, extensive wall thickening with stenosis and/or occlusion was found in 23 (82.1%) cases. Distal pulmonary lesions frequently involved two or three segments (21, 75.0%) and mainly presented as patchy consolidation or atelectasis (24, 85.7%).Conclusion: In combination to a history of eating peppers and clinical symptoms, bronchopneumonia caused by pepper should be highly suspected if U/V-shaped and annular high-density or localized soft tissue density is detected in the bronchi of the lower lobes, accompanied by extensive bronchial wall thickening, stenosis, or occlusion, and consolidation or atelectasis in multiple distal lung segments.Keywords: obstructive pneumonia, foreign body, pepper, computed tomography

To investigate the effect of natural spices on the shelf life quality of roasted peanut kernels, peanut kernels treated with aqueous extracts of turmeric, fennel, and peppercorns were subjected to accelerated oxidation using the Schaal oven method and were analyzed for acidity, peroxide, malondialdehyde, chroma colourimetry, textural composition, moisture content, water activity, and flavour sensory indexes during the period of storage in the oven, combined with the kinetics and the Arrhenius equation, the shelf life prediction model was completed at 20~63 ℃, validated and applied. The results showed that compared with the control group, the turmeric, fennel and peppercorn aqueous extract treatment groups could effectively inhibit the hydrolysis of oil and fatty acid oxidation, inhibit the increase of peroxide value and malondialdehyde, maintain the chromaticity and texture of peanuts better, and improve the flavour score of roasted peanuts. There was no significant difference between the moisture content of the spices groups and the control group. The water activity was less than 0.60, Aspergillus flavus struggled to thrive. The relative error of the resulting shelf life model was not more than 8.93%, which was used to quickly predict the shelf life of roasted peanuts stored at 20~63 ℃. When the storage temperature was 25 ℃, the shelf life was 170.6 days for turmeric-flavored peanuts, 150.5 days for fennel-flavored peanuts, 169.4 days for pepper-flavored peanuts, and 97.7 days for the control group. Therefore, adding turmeric, fennel and pepper can maintain the quality of the roasted peanuts and prolong their shelf life.

Plant basic helix-loop-helix (bHLH) transcription factors (TFs) play central roles in various abiotic stresses. However, its role in plant cold resistance is largely unknown. Previously, we characterised CaNAC035 in pepper, which positively regulates tolerance to cold, salt and drought stresses tolerance. Here, we identified CabHLH035, a CaNAC035-interacting protein in pepper. To explore its functions in cold stress tolerance, we silenced the gene in pepper via virus-induced gene silencing (VIGS) and overexpressed the gene in Arabidopsis. The results showed that CabHLH035 expression was induced by cold treatment, and silencing of CabHLH035 decreased cold stress tolerance. Conversely, overexpression of CabHLH035 in Arabidopsis increased cold stress tolerance. To investigate homologs genes of C-repeat binding factor (CBF) pathway proteins and reactive oxygen species (ROS) marker gene expression blocking by CabHLH035, we performed yeast one-hybrid (Y1H), dual luciferase and electrophoretic mobility shift assay experiments. The results showed that CabHLH035 bound to the region upstream of the CaCBF1A and CaAPX promoters. Additionally, CaCBF1A bound to the CaDHN4 promoter. Taken together, our results showed that CabHLH035 plays a crucial role in cold stress tolerance and its potential as a target for breeding cold-resistant crops. The findings provide a basis for studying the functions and regulatory network of cold stress tolerance in pepper.

In this study, the wild type 6421 and the fruit color mutant E55 of pepper were evaluated for fruit color, pigment contents and quality components at different developmental stages. The results demonstrated that the fruit color of 6421 and E55 changed from green to yellow and then to red, and from green to brown and then to orange, respectively, as the fruit developed from mature green to ripe. For both 6421 and E55, the color parameters a* and C* increased, while hue angle (h) value decreased. Furthermore, chlorophyll (Chl) content declined, whereas carotenoid (Car) content increased. Additionally, the contents of VC, soluble sugar, soluble protein and capsaicin increased, while cellulose content decreased. At the mature green stage, there was no significant difference between 6421 and E55 in five color parameters (L*, a*, b*, C*, and h values), Chl and Car contents or six quality indicators (cellulose, VC, soluble sugar, soluble protein, and capsaicin contents) (P > 0.05). During the color-turning to ripening stages, L*, b* and C* values and VC and soluble sugar contents were significantly higher and soluble protein and cellulose contents were significantly lower in E55 than in 6421 (p 0.05). Correlation analysis showed that for both 6421 and E55, Chl and Car contents were significantly or extremely significantly correlated with each quality parameter except for cellulose content. Among the tested quality indicators, soluble sugar, soluble protein, and capsaicin contents were significantly or extremely significantly positively correlated with each other, while cellulose content was significantly or highly significantly negatively correlated with the other indicators. This study can serve as a theoretical basis for research on the coloration mechanism of peppers as well as for the screening and breeding of high-quality pepper cultivars.

Abstract [Objective] Pepper is the largest vegetable crop planted in China. With the land salinization becoming more and more serious, it is urgent to accelerate the functional study of key genes related to pepper salt tolerance. It is of great significance to strengthen the study of mechanisms underlying salt tolerance in peper to promote sustainable development of the pepper industry. [Methods] In the early stage of research, CaNAC36, a NAC transcription factor family gene related to salt stress response in peppers, was discovered. Based on this, the full-length gDNA and cDNA sequences of CaNAC36 were cloned using salttolerant pepper accession PI201224 and salt-sensitive pepper accession PI438643. The expression of CaNAC36 and its interacting genes in different tissues under salt stress was quantitatively analyzed by fluorescence, and the potential relationship between CaNAC36 and its interacting genes was further explored by bioinformatics analysis. [Results] The gDNA and cDNA sequence homology of CaNAC36 in salt-tolerant and salt-sensitive materials were 99.86% and 100%, respectively. CaNAC36 showed an up-expression in roots and stems in the salt-tolerant pepper, and a down-expression in roots and leaves in the salt-sensitive peper. Throgh analyzing the annotation information of 48 genes that may interact with CaNAC36, it was found that 14 genes were belonging to transmembrane proteins, transporter proteins, water porins, chloride channel proteins, detoxifying proteins, and other genes, which may have functional interaction with CaNAC36. Further analysis revealed that PI201224 and PI438643 exhibited significant differences in the expression of five related genes, inclding Capana08g002748, Capana00g004514, Capana09g000275, Capana07g001450, Capana02g001031, at different time points and tissues under salt stress. Meanwhile, the promoter region of CaNAC36 and five associated genes was found to contain a large number of stressrelated cis-acting elements. [Conclusion] CaNAC36 was an important regulatory gene in pepper in response to salt stress, and might interact with other genes to improve salt tolerance.

Chitosan (CTS) is one of the natural healers’ alternatives to chemical products within the scope of good agricultural practices. It can be used in the improvement of agriculture (prevention of toxic metal uptake by plants) due to its chelating feature of metal ions. This study aims to investigate the effectiveness of chitosan in eliminating the negative effects of cadmium (Cd) stress on pepper (Capsicum annum L.). The results showed that Cd stress significantly decreased plant growth, chlorophyll content, and leaf water relative content, followed by an increase in proline, antioxidant enzyme activities, and abscisic acid (ABA) content. According to the results, Cd treatment (200 mg kg-1) significantly increased the aspartate, glutamate, asparagine, histidine, and phenylalanine content, while it significantly decreased the content of endogenous hormones such as gibberellic acid (GA), indole-3-acetic acid (IAA), and salicylic acid (SA). However, CTS application decreased the uptake of Cd and caused a decrease in hydrogen peroxide (H2O2), abscisic acid (ABA), and melondialdehyde (MDA) content, as well as an increase in plant performance, and GA, IAA, and SA content in the plants grown under Cd pollution compared to the ones treated with Cd and without CTS. This study suggests that CTS application helps pepper seedlings tolerate Cd stress through a decrease in Cd uptake, and an increase in amino acids and hormone content.

Grafting onto pepper rootstock NIBER® is an effective strategy to mitigate water stress effects on the grafted variety. In this work, we comparatively explored the metabolomic responses to water stress in the pepper variety “Maestral F1” (V) grafted onto NIBER® (V/N) and self-grafted (V/V) by untargeted metabolomics on leaves and roots. Leaf water status was also evaluated by relative water content (RWC) and gas exchange measurements. Under water stress, the V/N water use efficiency (WUE) and leaf RWC were higher than V/V, in agreement with major stomata closure and water retention in leaves. V/N showed a tolerance response, which was manifested in the untargeted metabolomic analysis. NIBER® modulated the grafted variety response to water stress as reflected in the differential metabolomic profiles in leaves and roots. The V/N-enriched metabolic pathways showed that the NIBER® response to water stress involved cutin and suberin biosynthesis, which act as protection layers, and jasmonic acid (JA) and jasmonates biosynthesis to favor signaling pathways. NIBER® did not induce flavonols and chlorophyll b synthesis, but likely promoted anthocyanins biosynthesis and maintained an undisturbed chlorophyll a:chlorophyll b ratio. Moreover, NIBER® increased vitamin B6, anthocyanins and stearic acid concentration in the variety leaves, whereas siroheme content rose in roots to improve nitrogen assimilation. Further studies are required to understand the contribution of secondary metabolites, such as phenylpropanoids, glycoalkaloids, and nitrogen-containing secondary metabolites, to NIBER® water stress tolerance.

Capsaicinoids are produced uniquely in pepper fruits, and its level determines the commercial quality and health-promoting properties of pepper. So, it is particularly important to increase capsaicinoids content in pepper. Rhizosphere microbiota is critical to plant growth and performance, and affected by plant varieties. However, the impact of pepper varieties with different capsaicinoids yields on the rhizosphere microbiota is poorly understood. Using high-throughput sequencing of the 16S rRNA and internal transcribed spacer (ITS) region, we investigated the rhizosphere microbial community among five pepper varieties containing different capsaicinoids. Our results demonstrated that pepper variety significantly influenced the diversity and structure of rhizosphere microbial community. Bacterial diversity in varieties with high capsaicinoids content was significantly higher than in varieties with low capsaicinoids content, while fungal diversity was opposite to bacterial diversity. The correlation analysis revealed that 19 dominant bacterial genera (e.g., Chujaibacter, Rhodanobacter, and Gemmatimonas) were significantly correlated with capsaicinoids content, and nine of them were also significantly associated with soil nutrients, whereas only one fungal genus (Podospora) was significantly correlated with capsaicinoids content. Additionally, almost all genera which significantly correlated to capsaicinoids content were biomarkers of the five pepper varieties and the correlation was well corresponding to the capsaicinoids content. Overall, our results confirmed that the variety of pepper significantly affected the rhizosphere microbial community in the fields, and bacteria and fungi responded differently to capsaicinoids, which may affect the biosynthesis of capsaicinoids and contribute to further improvement of capsaicinoids production in pepper fruits.

The SBP-box gene significantly influences plant growth, development, and stress responses, yet its function in pepper plants during drought stress remains unexplored. Using virus-induced gene silencing and overexpression strategies, we examined the role of CaSBP13 during drought stress in plants. The results revealed that the expression of CaSBP13 can be induced by drought stress. Silencing of CaSBP13 in pepper notably boosted drought resistance, as evident by decreased active oxygen levels. Furthermore, the water loss rate, relative electrical conductivity, malondialdehyde content, and stomatal density were reduced in CaSBP13-silenced plants compared to controls. In contrast, CaSBP13 overexpression in Nicotiana benthamiana decreased drought tolerance with elevated reactive oxygen levels and stomatal density. Additionally, ABA signaling pathway genes (CaPP2C, CaAREB) exhibited reduced expression levels in CaSBP13-silenced plants post drought stress, as compared to control plants. On the contrary, CaPYL9 and CaSNRK2.4 showed heightened expression in CaSBP13-sienced plants under the same conditions. However, a converse trend for NbAREB, NbSNRK2.4, and NbPYL9 was observed post-four day drought in CaSBP13-overexpression plants. These findings suggest that CaSBP13 negatively regulates drought tolerance in pepper, potentially via ROS and ABA signaling pathways.

IntroductionDomestic production of pepper (Capsicum spp.) is shrinking while demand within the US is growing. Lack of availability and cost of labor often present an obstacle for domestic producers both practically and economically. As a result, switching to harvesting peppers mechanically is anticipated as a key strategy to help domestic producers compete in the international market. Mechanical harvest efficiency can be improved through breeding. One important trait that mechanical harvest compatible material should have is an easy destemming trait: low force separation of the pedicel and calyx from the fruit.MethodsTo detect the genetic sources underlying a novel easy destemming trait for the purpose of future breeding efforts in New Mexico pod-type green chile, we performed QTL analysis on three F2:F3 populations, coming from three New Mexico pod-type varieties: ‘NuMex Odyssey,’ ‘NuMex Iliad,’ and ‘NuMex Joe E. Parker,’ each crossed with a parent with an easy destemming trait: MUC14. Genotyping was done through genotyping by sequencing (GBS) and phenotyping was done for destemming and fruit trait measurements. Correlations between measurements were found through the R package hmisc and QTL analysis was done through R/qtl.ResultsA strong relationship was seen between destemming and aspects of fruit morphology, particularly, destemming force and fruit width (Pearson’s correlation coefficient r=0.75). Major QTLs for destemming and fruit size were discovered. Of these, the largest destemming force QTLs for all populations (PVE=34.5-69.9%) were on chromosome 10, and in two populations QTLs for destemming force were found on chromosome 3 (Percent Variance Explained (PVE)=10.7-18.8%). Fruit size-related QTLs in all populations colocalized in these same areas on chromosomes 3 and 10.DiscussionThis suggests that fruit shape may be genetically linked to destemming, and breeders interested in selecting for easy destemming pepper will also have to pay attention to fruit size and shape.

【Objective】The genetic transformation of pepper mediated by Agrobacterium was a very difficult process, and no efficient transformation system had been established so far.Green fluorescent protein (GFP) gene is a common reporter gene in plant genetic transformation.In the study, GFP was used as the reporter gene to optimize the Agrobacterium-mediated genetic transformation system of pepper.【Method】By using GFP expression system, three types of explants(cotyledons, hypocotyls and Flamingo-bill explants)from 3 pepper varieties('HP' '8214' and 'L55')were counted according to the adventitious bud differentiation rate, adventitious root differentiation rate and fluorescence positive rate.The effects of factors including infection concentration and infection time, pre-culture time and co-culture time on adventitious bud differentiation rate, adventitious root differentiation rate and fluorescence positive rate were explored.【Result】The adventitious bud differentiation rate of Flamingo-bill explants was significantly higher than that of the hypocotyl and cotyledon explants, among which the 'L55' Flamingo-bill explant had the highest adventitious bud differentiation rate of 77.59%.Therefore, the 'L55' Flamingo-bill explant was selected for subsequent research.Under 4 different combinations of Agrobacterium infection concentration and infection time, all of them could produce adventitious buds, adventitious roots and GFP-expressing calluses.When the infection concentration of Agrobacterium was OD600=0.05 and the infection time was 30 min, the adventitious bud differentiation rate and fluorescence positive rate of Flamingo-bill explants were the highest, reaching 48.39% and 4.84%, respectively.Under 6 different pre-culture and co-culture time combinations, the Flamingo-bill explants also produced adventitious buds and adventitious roots, and the highest adventitious bud differentiation rate and fluorescence positive rate were 48.44% and 12.50%, respectively, under the treatment of pre-culture for 1 d and co-culture for 1-2 d.Finally, PCR detection of adventitious roots and calluses with GFP fluorescence expression showed that the 3 target genes GFP, Kan and Cas9 all presented signal in the fluorescence positive tissues, indicating that the T-DNA insertion mediated by Agrobacterium was successful and the transformation was stable.【Conclusion】The explant type of pepper, Agrobacterium infection concentration, infection time, pre-culture time and co-culture time all have effects on the genetic transformation efficiency of pepper.Screening appropriate transformation conditions with GFP as a reporter gene could improve the efficiency of Agrobacterium-mediated genetic transformation of pepper.

Abstract Background The B3 gene family, one of the largest plant-specific transcription factors, plays important roles in plant growth, seed development, and hormones. However, the B3 gene family, especially the REM subfamily, has not been systematically and functionally studied. Results In this study, we performed genome-wide re-annotation of B3 genes in five Solanaceae plants, Arabidopsis thaliana, and Oryza sativa, and finally predicted 1,039 B3 genes, including 231 (22.2%) newly annotated genes. We found a striking abundance of REM genes in pepper species (Capsicum annuum, Capsicum baccatum, and Capsicum chinense). Comparative motif analysis revealed that REM and other subfamilies (ABI3/VP1, ARF, RAV, and HSI) consist of different amino acids. We verified that the large number of REM genes in pepper were included in the specific subgroup (G8) through the phylogenetic analysis. Chromosome location and evolutionary analyses suggested that the G8 subgroup genes evolved mainly via a pepper-specific recent tandem duplication on chromosomes 1 and 3 after speciation between pepper and other Solanaceae. RNA-seq analyses suggested the potential functions of REM genes under salt, heat, cold, and mannitol stress conditions in pepper (C. annuum). Conclusions Our study provides evolutionary and functional insights into the REM gene family in pepper.

This study assessed the influence of exogenous ME in the mitigation of cold damage in pepper seedlings. Melatonin (ME) is a dynamic molecule that helps plants cope with stress in several ways. Cold stress (CS) is one of the most important environmental factors that restrict plant growth and yield. Pepper (Capsicum annuum L.) is a valuable commercial crop, highly sensitive to CS. Thus, identifying an efficient strategy to mitigate cold damage is critical for long-term pepper production. For this purpose, the roots of pepper seedlings were pretreated with ME (5 μmol · L−1) and exposed to CS for 7 d. The results indicated that CS suppressed pepper growth, hampered photosynthetic capacity, and damaged root architecture in pepper plants. In contrast, the production of reactive oxygen species (ROS), malondialdehyde (MDA), electrolyte leakage (EL), proline, and soluble sugars were enhanced in plants under CS. ME (5 μmol · L−1) pretreatment reduced the negative effects of CS by recovering plant growth, root traits, gas exchange elements, and pigment molecules compared to CS control treatment. Furthermore, ME application efficiently reduced oxidative stress markers [hydrogen peroxide (H2O2), superoxide ion (O2·–), EL, and MDA] while increasing proline and soluble sugar content in pepper leaves. ME application combined with CS further increased antioxidant enzymes and related gene expression. Collectively, our results confirmed the mitigating potential of ME supplementation for CS by maintaining pepper seedling growth, improving the photosynthesis apparatus, regulating pigments, and osmolyte content.

Pepper (Capsicum spp.) belongs to the genus Capsicum in the Solanaceae family and is widely cultivated around the world as a vegetable and spice crop. In addition to its application as a cooking ingredient and spice, pepper also has a wide range of uses in the pharmaceutical and cosmetic fields. Carotenoids are a class of natural pigments involved in many important metabolic processes in plants, such as photosynthesis, photoprotection, photomorphogenesis and growth and development. Carotenoid is one of the main nutrients of pepper fruit, which has various biological activities. To cultivate varieties with higher carotenoid content, it is necessary to understand its biosynthesis and molecular mechanism of regulation. The development of molecular biology and biotechnology has promoted the identification of carotenoid biosynthesis genes, providing opportunities for breeding new varieties of pepper with higher carotenoid content. In this review, the physiological role of carotenoid, carotenoid and pepper fruit color, carotenoid biosynthesis pathway, structural genes and regulatory factors of carotenoid biosynthesis pathway, molecular genetics of pepper fruit color and QTL sites related to pepper fruit color are described. GGPS, PSY, PDS, ZDS, LCY, CCS are port enzymes and rate-limiting enzymes in the carotenoid biosynthesis pathway of pepper, and the expression abundance and activity of them directly regulate the carotenoid content in pepper. Transcription factors such as MYB306, DIVARICATA1 and BBX20 are involved in the regulation of carotenoid biosynthesis in pepper. The diversity of carotenoid biosynthesis and regulatory genes determines the amount and content of carotenoid monomer and affects the color of pepper fruit. Based on the current research progress, future research on carotenoid metabolism of pepper is prospected in order to provide new ideas for breeding new varieties of biofortified pepper rich in carotenoids in the future.

Abstract Phytophthora blight severely threatens global pepper production. Grafting bolsters plant disease resistance, but the underlying molecular mechanisms remain unclear. In this study, we used P. capsici-resistant strain ‘ZCM334’ and susceptible strain ‘Early Calwonder’ for grafting. Compared to self-rooted ‘Early Calwonder’ plants, ‘ZCM334’ grafts exhibited delayed disease onset, elevated resistance, and reduced leaf cell damage, showcasing the potential of grafting in enhancing pepper resistance to P. capsici. Proteomic analysis via the iTRAQ technology unveiled 478 and 349 differentially expressed proteins (DEPs) in the leaves and roots, respectively, between the grafts and self-rooted plants. These DEPs were linked to metabolism and cellular processes, stimulus responses, and catalytic activity and were significantly enriched in the biosynthesis of secondary metabolites, carbon fixation in photosynthetic organizations, and pyruvate metabolism pathways. Twelve DEPs exhibiting consistent expression trends in both leaves and roots, including seven related to P. capsici resistance, were screened. qRT-PCR analysis confirmed a significant correlation between the protein and transcript levels of DEPs after P. capsici inoculation. This study highlights the molecular mechanisms whereby grafting enhances pepper resistance to Phytophthora blight. Identification of key genes provides a foundation for studying the regulatory network governing the resistance of pepper to P. capsici.

Pepper (Capsicum annuum L.), as one of the most important vegetable crops, requires continuous work on the selection of new varieties and hybrids with greater genetic potential for fertility, and the introduction of new cultivation technologies, all to satisfy human needs. In the first year of research, after crossing two parental components based on sterile lines, hybrid seeds of experimental hybrids were produced. A comparative experiment was set up in the greenhouse of the Institute for Vegetable Crops Smederevska Palanka in 2023 to create new pepper hybrids, which are characterized by fruits for different purposes. Of the seven experimental hybrid combinations, one is selected (LPK027 x HM6) for its potential morphological features (fruit weight and number of fruits per plant) as the main components of yield and high content of dry matter and was reported to the Commission for the Recognition of New Varieties in 2024 under the name Katja F1.

The aim of the research was to evaluate the influence of the hybrid and the medium for germination testing on indicators of pepper seed quality. The obtained results should provide an answer as to whether the application of different growing media for testing seed germination can lead to discrepancies between test results in quality indicators for hybrid seeds. The seed quality of three pepper hybrids: KG 2025 F1, KG 2129 F1 and KG 2032 F1 was tested on two growing media (filter paper and substrate). Statistical analysis of germination energy, total germination, diseased seedlings and dead seeds showed highly significant differences (r

This study aimed to investigate the effects of auxin types and their concentrations on rooting of the rootstock cuttings and BA on grafting. First, IBA, NAA or IBA+NAA, each at 0, 1000, 2000, and 3000 ppm were used as treatments to study rooting of Piper colubrinum. In the second experiment, BA (0 and 50 ppm) was applied to P. nigrum scion clones of Natar-1 and Petaling-2, before being grafted to the rootstocks. Results showed, that all types of auxins (IBA, NAA or IBA+NAA) induced rooting and shoot growth, and the increase of auxin concentrations led to the increase of rooting. However, their effectiveness was different. NAA and IBA+NAA were superior to IBA, and at 2000 ppm, IBA+NAA resulted in the best plant growth, as indicated by higher values of both rooting and shoot growth parameters. Compared to control, BA treatment on scions resulted in higher grafting success (80% vs. 93%) for Natar-1, and (73% vs.100%) for Petaling-2 clones. BA treatment on scions also induced more calluses in the graft union and better shoot growth. To our knowledge, this is the first report on the use of BA to increase success of grafting between P. nigrum and P. colubrinum.

Due to the vulnerability of pepper (Capsicum spp.) and the virulence of tomato spotted wilt virus (TSWV), seasonal shortages and surges of prices are a challenge and thus threaten household income. Traditional bioassays for detecting TSWV, such as observation for symptoms and reverse transcription-PCR, are time-consuming, labor-intensive, and sometimes lack precision, highlighting the need for a faster and more reliable approach to plant disease assessment. Here, two imaging techniques—Red–Green–Blue (RGB) and hyperspectral imaging (using NDVI and wavelength intensities)—were compared with a bioassay method to study the incidence and severity of TSWV in different pepper accessions. The bioassay results gave TSWV an incidence from 0 to 100% among the accessions, while severity ranged from 0 to 5.68% based on RGB analysis. The normalized difference vegetative index (NDVI) scored from 0.21 to 0.23 for healthy spots on the leaf but from 0.14 to 0.19 for disease spots, depending on the severity of the damage. The peak reflectance of the disease spots on the leaves was identified in the visible light spectrum (430–470 nm) when spectral bands were studied in the broad spectrum (400.93–1004.5 nm). For the selected wavelength in the visible light spectrum, a high reflectance intensity of 340 to 430 was identified for disease areas, but between 270 and 290 for healthy leaves. RGB and hyperspectral imaging techniques can be recommended for precise and accurate detection and quantification of TSWV infection.

The root-knot nematode Meloidogyne enterolobii is a major constraint to pepper production in tropical regions. In the long-term practice of root-knot nematode management, bacterial nematicides have attracted increasing attention as effective biocontrol agents. In this study, we evaluated the efficacy of Bacillus thuringiensis strain 00-50-5 (Bt 00-50-5) against M. enterolobii through in vitro, greenhouse and field trials. The cell-free supernatant of Bt 00-50-5 exhibited potent nematicidal activity against second-stage juveniles (J2s) of M. enterolobii, with mortality rates of 98.0% and 100% after 24 h and 36 h of exposure, respectively. In addition, Bt 00-50-5 showed inhibitory effects on the hatching of M. enterolobii eggs, resulting in a remarkable 96.6% reduction in the egg hatching rate after 6 days compared to the control. The pot trials showed that both pepper root galls and egg masses were reduced, and plant growth was improved after treatment with Bt 00-50-5. The field trials showed that the gall index was significantly reduced, with a 66.3% and 68.2% reduction in disease index in 2020–2021 and 2021–2022, respectively, and pepper yield was improved, with a 96.2% and 93.1% increase in yield in 2020–2021 and 2021–2022, respectively, compared to the control. These results indicate the potential use of Bt 00-50-5 as an effective biocontrol agent against M. enterolobii.

Pepper (Capsicum annuum) is a globally important vegetable, and Verticillium wilt is an important disease affecting peppers and is caused by Verticillium dahliae, which can severely reduce yields. However, the molecular mechanisms underlying the responses of pepper to infection by V. dahliae are largely unknown. We performed physiological and transcriptome analysis using resistant and susceptible pepper cultivars inoculated with V. dahliae. Compared to the susceptible cultivar MS66, the resistant cultivar MS72 retained higher chlorophyll content and lower malondialdehyde content after inoculation. At 3 days after inoculation (DAI), compared with MS66, 534 differentially expressed genes (DEGs) were identified in MS72. At 5 DAI, 2392 DEGs were identified in MS72 compared with MS66. The DEGs in MS72 were mainly enriched in the cell wall and photosynthesis-related Gene Ontology terms, as well as in pathways such as cutin, suberin, wax biosynthesis, phenylpropanoid biosynthesis, and photosynthesis. Using weighted gene co-expression network analysis, 36 hub genes involved in the resistance response were identified, including the transcription factor bHLH93 (Capana04g000815), defense-like protein 1 (MSTRG.5904), and miraculin-like (Capana10g002167). Our findings contribute to a more comprehensive understanding of the response mechanism of pepper to V. dahliae inoculation, providing new avenues for improving pepper resistance through breeding programs.

Abiotic stress is one of the key factors harming global agriculture today, seriously affecting the growth and yield of vegetables. Pepper is the most widely grown vegetable in the world, with both high nutritional and economic values. Currently, the increase in global extreme weather events has heightened the frequency of abiotic stresses, such as drought, high and low temperatures, waterlogging, and high salt levels, which impairs pepper growth and development, leading to its reduced yield and quality. In this review, we summarize the research progress on the responses of pepper to abiotic stress in recent years in terms of physiology, biochemistry, molecular level, and mitigation measures. We then explore the existing problems and propose future research directions. This work provides a reference for the cultivation and development of new pepper varieties resistant to abiotic stress.

Salt stress is a major abiotic factor that negatively impacts the growth, performance, and secondary metabolite production in pepper (Capsicum annuum L.) plants. Brassinosteroids (BRs) play a crucial role in enhancing plant tolerance to abiotic stress, yet their potential in mitigating salt stress in pepper plants, particularly by promoting sugar and glycine betaine accumulation, remains underexplored. In this study, we investigated the effects of the foliar application of 2,4-epibrassinolide (EBR) on salt-stressed pepper seedlings. Our findings revealed that EBR treatment significantly increased the levels of proline, sugar, and glycine betaine under salt stress compared to untreated controls. Moreover, EBR enhanced the antioxidant defense mechanisms in pepper seedlings by increasing sugar and glycine betaine levels, which contributed to the reduction of reactive oxygen species (ROS) and malondialdehyde (MDA) accumulation.