Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico

Capsaicinoid Profiles, Phenolic Content, and Antioxidant Properties of Chili Peppers Grown in Urban Settings

The Capsicum genus, native to the Americas and cultivated worldwide for culinary and medicinal purposes, includes five domesticated species with diverse fruit characteristics, pungency, and phytochemical profiles. However, the influence of casual urban backyard growing conditions on these traits remains unknown. In this study, we first assessed morphological production traits of 11 popular pepper cultivars over two growing seasons to establish a consistent baseline for cultivar performance. Next, we evaluated capsaicinoid and phenolic profiles of 47 pepper cultivars, which contribute to their pungency and antioxidant properties. Capsaicinoid profiles revealed species-specific ratios of capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, with C. annuum and C. baccatum displaying an average 64:30:6 profile, C. chinense and C. frutescens showing a capsaicin-dominant 73:25:2 profile, and C. pubescens expressing a distinct dihydrocapsaicin-dominant 34:60:6 profile. Antioxidant activity positively correlated with capsaicinoid content (ABTS: R2 = 0.8264, p < 0.0001; FRAP: R2 = 0.8117, p < 0.0001), with C. chinense (Carolina Reaper) exhibiting the highest activity (FRAP = 111.8 µM TE/g). In LPS-activated macrophages, all cultivars suppressed nitric oxide production both at the enzymatic (66-89%, p < 0.001) and gene expression levels (4.2 to 5.3-fold reduction, p < 0.05). Interleukin IL-1β expression was upregulated (3.8 to 12.9-fold, p < 0.001), while no significant effects were noted on Cox-2, IL-6, and MCP-1 mRNA levels. These results provide novel insights into the molecular and biochemical adaptations of peppers grown in urban environments and underscore the importance of optimizing cultivation conditions to maximize their bioactive potential and health benefits.

Role of Metal-Based Nanoparticles in Capsicum spp. Plants

Agriculture is a core activity in human civilization, constantly facing challenges with the main objective of increasing crop production; to solve this, different strategies and technologies have been used. Currently, metal-based nanoparticles (MNPs) have great potential to be used as agricultural inputs to mitigate the negative effects on crops caused by different stresses. However, studies about their impact on plants and agroecosystems require a comprehensive understanding of their effects. Chili pepper (Capsicum spp.) is a crop of global economic importance that could benefit from the use of MNPs in order to increase its production. The effects of MNPs depend on factors such as their composition, morphology, size, concentration, and application method. Both in vitro and greenhouse studies have demonstrated improvements in plant growth, response to abiotic stresses, and the induction of resistance to different pathogens. However, results vary considerably from one study to another, probably due to heterogeneity in synthesis, characterization, and application methods. This review examines recent findings about the effects of MNPs on chili pepper crops, focusing on growth, development, bioaccumulation, and response to biotic and abiotic stresses.

Genomic insights into Mediterranean pepper diversity using ddRADSeq

This work investigated the genetic diversity and population structure of 99 pepper lines (Capsicum annuum L.), acclimated to Mediterranean climate conditions, using double-digest restriction site-associated DNA sequencing (ddRADSeq). The aims were to understand the genetic relationships among these lines, correlate genetic clusters with botanical classifications, and provide insights into pepper domestication in the region. Obtained were 318.76 million raw sequence reads overall, averaging 3.21 million reads per sample. A total of 8475 high-quality SNPs were identified and used to assess genetic diversity and population structure. Chromosome NC_061113.1 displayed the highest amount and Chromosome NC_061118.1 the fewest of these SNPs, which were not equally spaced around the genome. Heterozygosity measures and a negative inbreeding coefficient point to the great genetic diversity seen, therefore highlighting the genetic health of the population. Different genetic clusters found by phylogenetic study and STRUCTURE analysis can be used in breeding programs to mix desired features from many genetic backgrounds. This work showed how well ddRADSeq generates high-quality SNPs for genomic research on peppers, therefore offering useful molecular tools for genomic selection and marker-assisted selection. The analysis identified significant genetic diversity and distinct genetic clusters which are valuable for breeding programs focused on crop improvement. These findings enhance our understanding of pepper domestication and provide valuable genetic resources for breeding programs aimed at improving pepper varieties.

Transposon proliferation drives genome architecture and regulatory evolution in wild and domesticated peppers

Pepper (Capsicum spp.) is a widely consumed vegetable with exceptionally large genomes in Solanaceae, yet its genomic evolutionary history remains largely unknown. Here we present 11 high-quality Capsicum genome assemblies, including two gap-free genomes, covering four wild and all five domesticated pepper species. We reconstructed the ancestral karyotype and inferred the evolutionary trajectory of peppers. The expanded and variable genome sizes were attributed to differential transposable element accumulations, which shaped 3D chromatin architecture and introduced mutations associated with traits such as fruit orientation and colour. Using a chromatin accessibility atlas of Capsicum, we highlight the influence of transposable elements on regulatory element evolution. Furthermore, by constructing a haploblock map of 124 pepper core germplasms, we uncover frequent introgressions that facilitate the formation of sweet blocky pepper and the acquisition of important traits such as resistance to pepper mild mottle virus. These findings on the genomic and functional evolution of Capsicum will benefit pepper breeding.

Transcriptomics and Metabolomics Reveal Biosynthetic Pathways and Regulatory Mechanisms of Phenylpropanes in Different Ploidy of Capsicum frutescens

Pepper is a significant cash crop, and Capsicum frutescens is an exemplary variety of pepper cultivated for its distinctive flavor and substantial nutritional value. Polyploidization of plants often leads to an increase in their biomass and improved stress tolerance, and thus has important applications in plant breeding and improvement. In this study, germplasm innovation was carried out by polyploidy induction of C. frutescens by colchicine. To investigate the effects of polyploidization on C. frutescens, we conducted transcriptomic and metabolomic analyses of diploids and homotetraploids of C. frutescens to gain insights into the mechanisms of metabolite composition and molecular regulation of C. frutescens by polyploidization. Based on the analysis of metabolomics and transcriptomics data, a total of 551 differential metabolites were identified in the leaves of C. frutescens of different ploidy and 634 genes were significantly differentially expressed. In comparison, 241 differential metabolites and 454 genes were significantly differentially expressed in the mature fruits of C. frutescens of different ploidy. Analysis of KEGG enrichment of differentially expressed genes and differential metabolites revealed that both differential metabolites and differentially expressed genes were highly enriched in the phenylalanine metabolic pathway. It is worth noting that phenylpropanoids are highly correlated with capsaicin synthesis and also have an effect on fruit development. Therefore, we comprehensively analyzed the phenylalanine metabolic pathway and found that chromosome doubling significantly down-regulated the expression of genes upstream of phenylalanine (PAL, 4CL), which promoted lignin accumulation, and we suggested that this might have led to the enlargement of polyploid C. frutescens fruits. This study provides some references for further research on the phenotypic traits of different ploidy of C. frutescens, cloning of key regulatory genes, and using genetic engineering techniques in C. frutescens breeding for germplasm improvement.

Interdisciplinary insights into the cultural and chronological context of chili pepper (Capsicum annuum var. annuum L.) domestication in Mexico

This study investigates the temporal and spatial factors driving the domestication of Capsicum annuum var. annuum L. in Mexico. This species exhibits the greatest morphological diversity in fruit among Capsicum species-a characteristic that is even more pronounced in contemporary landraces cultivated by indigenous communities. Despite the chili pepper's integral role in regional culinary traditions, its domestication history in this region remains poorly understood, often subject to scholarly interpretations that marginalize or oversimplify archaeological evidence. To address this gap, our interdisciplinary team of archaeologists, botanists, and ecologists combine modern and archaeological Capsicum seed data, diachronic archaeological site locations, and ecological niche modeling to identify potential regions where early human populations and the closest wild ancestors may have coexisted. Our results show spatial correlations between early Capsicum distribution and archaeological site prevalence, suggesting that the beginning of the domestication process occurred in ecologically suitable areas for both wild Capsicum and human settlement. These findings challenge previous hypotheses regarding highland/dry cave domestication regions, as our data indicate that lowland regions-specifically the Yucatán Peninsula and southern coastal Guerrero-were more conducive to early encounters between wild Capsicum and humans. We propose a geographically diffuse and protracted model of chili pepper domestication-driven by a ruderal pathway-which involved at least two asynchronous events across Mexico.

The milpa, from Mesoamerica to present days, a multicropping traditional agricultural system serving agroecology

The association of maize (Zea mays ssp. mays), common bean (Phaseolus vulgaris), and squash (Cucurbita ssp.) within the milpa represents the most emblematic multi-cropping subsistence system of Mesoamerica. This system was likely established in the Guerrero-Jalisco area in southwestern Central Mexico shortly after—or perhaps even before—the domestication of the three taxa. Its success relies on several factors: complementarity of nutritional intakes, resilience to biotic and abiotic constraints, and the mobilization of positive interactions between the three taxa, enabling the system to be productive under input-limited conditions. Higher yields compared to sole-cropping have frequently been described and attributed to the complementarity between the aerial and root systems of the different taxa of the milpa, as well as to direct and indirect facilitation processes involving root exudates, bacterial symbioses, and the mycorrhizal network. In Europe, while practiced until recently, the milpa has gradually been abandoned in favor of maize sole-cropping, except in some isolated regions (such as Transylvania) where this traditional agricultural system has persisted. The question of whether varieties of the three taxa used in multi-cropping systems were co-introduced to Europe at the time of the discovery of the Americas, as opposed to being re-associated later in Europe, remains open. It is important to note that maize usage differed: maize of flint type is coarsely ground for the preparation of polenta in Europe, while in Mesoamerica, tropical varieties are soaked in alkaline solution to improve nutritional quality before being finely ground to make tortilla dough. Recently, maize-bean intercropping has been reintroduced into modern European agricultural systems. However, the use of elite varieties and chemical inputs in conventional conducts prevents full exploitation of positive interactions between species. We argue here that milpa has an important role to play in the agroecological transition. In this context, we propose avenues for the selection of varieties that promote synergies between species and discuss the constraints linked to its mechanization.

Biocontrol Activity of Bacillus altitudinis CH05 and Bacillus tropicus CH13 Isolated from Capsicum annuum L. Seeds against Fungal Strains

In this study, seed-surface-associated bacteria from fresh fruits of Capsicum spp. were analyzed to explore potential isolates for biocontrol of phytopathogenic fungal strains. A total of 76 bacterial isolates were obtained from three different species of chili pepper (C. annuum L., C. pubescens R. & P., and C. chinense Jacq.), and two isolates were selected via mycelial growth inhibition assays based on their production of volatile organic compounds (VOCs) against six fungal strains. Genomic analysis identified these isolates as Bacillus altitudinis CH05, with a chromosome size of 3,687,823 bp and with 41.25% G+C, and Bacillus tropicus CH13, with a chromosome size of 5,283,706 bp and with 35.24% G+C. Both bacterial strains showed high mycelial growth inhibition capacities against Sclerotium rolfsii, Sclerotinia sp., Rhizoctonia solani, and Alternaria alternata but lower inhibition capacities against Colletotrichum gloesporoides and Fusarium oxysporum. VOC identification was carried out after 24 h of fermentation with 64 VOCs for B. altitudinis CH05 and 53 VOCs for B. tropicus CH13. 2,5-Dimethyl pyrazine and acetoin had the highest relative abundance values in both bacterial strains. Our findings revealed that seed-surface-associated bacteria on Capsicum spp. have the metabolic ability to produce VOCs for biocontrol of fungal strains and have the potential to be used in sustainable agriculture.

Native arbuscular mycorrhizal fungi drive ecophysiology through phenotypic integration and functional plasticity under the Sonoran desert conditions

Knowledge is scarce to what extent environmental drivers and native symbiotic fungi in soil induce abrupt (short-term), systemic (multiple traits), or specific (a subset of traits) shifts in C3 plants' ecophysiological/mycorrhizal responses. We cultivated an emblematic native C3 species (Capsicum annuum var. glabriusculum, "Chiltepín") to look at how the extreme heat of the Sonoran desert, sunlight regimes (low = 2, intermediate = 15, high = 46 mol m2 d-1) and density of native arbuscular mycorrhizal fungi in soil (low AMF = 1% v/v, high AMF = 100% v/v), drive shifts on mycorrhizal responses through multiple functional traits (106 traits). The warming thresholds were relentlessly harsh even under intensive shade (e.g. superheat maximum thresholds reached ranged between 47-63°C), and several pivotal traits were synergistically driven by AMF (e.g. photosynthetic capacity, biomass gain/allometry, and mycorrhizal colonization traits); whereas concurrently, sunlight regimes promoted most (76%) alterations in functional acclimation traits in the short-term and opposite directions (e.g. survival, phenology, photosynthetic, carbon/nitrogen economy). Multidimensional reduction analysis suggests that the AMF promotes a synergistic impact on plants' phenotypic integration and functional plasticity in response to sunlight regimes; however, complex relationships among traits suggest that phenotypic variation determines the robustness degree of ecophysiological/mycorrhizal phenotypes between/within environments. Photosynthetic canopy surface expansion, Rubisco activity, photosynthetic nitrogen allocation, carbon gain, and differential colonization traits could be central to plants' overall ecophysiological/mycorrhizal fitness strengthening. In conclusion, we found evidence that a strong combined effect among environmental factors in which AMF are key effectors could drive important trade-offs on plants' ecophysiological/mycorrhizal fitness in the short term.

Developing an Optimized Protocol for Regeneration and Transformation in Pepper

Capsicum annuum L. is extensively cultivated in subtropical and temperate regions globally, respectively, when grown in a medium with 8 holding significant economic importance. Despite the availability of genome sequences and editing tools, gene editing in peppers is limited by the lack of a stable regeneration and transformation method. This study assessed regeneration and transformation protocols in seven chili pepper varieties, including CM334, Zunla-1, Zhongjiao6 (ZJ6), 0818, 0819, 297, and 348, in order to enhance genetic improvement efforts. Several explants, media compositions, and hormonal combinations were systematically evaluated to optimize the in vitro regeneration process across different chili pepper varieties. The optimal concentrations for shoot formation, shoot elongation, and rooting in regeneration experiments were determined as 5 mg/L of 6-Benzylaminopurine (BAP) with 5 mg/L of silver nitrate (AgNO3), 0.5 mg/L of Gibberellic acid (GA3), and 1 mg/L of Indole-3-butyric acid (IBA), respectively. The highest regeneration rate of 41% was observed from CM334 cotyledon explants. Transformation optimization established 300 mg/L of cefotaxime for bacterial control, with a 72-h co-cultivation period at OD600 = 0.1. This study optimizes the protocols for chili pepper regeneration and transformation, thereby contributing to genetic improvement efforts.

Dissection of Metabolome and Transcriptome-Insights into Capsaicin and Flavonoid Accumulation in Two Typical Yunnan Xiaomila Fruits

Pepper is an economically important vegetable worldwide, containing various specialized metabolites crucial for its development and flavor. Capsaicinoids, especially, are genus-specialized metabolites that confer a spicy flavor to Capsicum fruits. In this work, two pepper cultivars, YB (Capsicum frutescens L.) and JC (Capsicum baccatum L.) pepper, showed distinct differences in the accumulation of capsaicin and flavonoid. However, the molecular mechanism underlying them was still unclear. Metabolome analysis showed that the JC pepper induced a more abundant accumulation of metabolites associated with alkaloids, flavonoids, and capsaicinoids in the red ripening stages, leading to a spicier flavor in the JC pepper. Transcriptome analysis confirmed that the increased expression of transcripts associated with phenylpropanoid and flavonoid metabolic pathways occurred in the JC pepper. Integrative analysis of metabolome and transcriptome suggested that four structural genes, 4CL7, 4CL6, CHS, and COMT, were responsible for the higher accumulation of metabolites relevant to capsaicin and flavonoids. Through weighted gene co-expression network analyses, modules related to flavonoid biosynthesis and potential regulators for candidate genes were identified. The promoter analysis of four candidate genes showed they contained several cis-elements that were bonded to MYB, bZIP, and WRKY transcription factors. Further RT-qPCR examination verified three transcription factors, MYB, bZIP53, and WRKY25, that exhibited increased expression in the red ripening stage of the JC pepper compared to YB, which potentially regulated their expression. Altogether, our findings provide comprehensive understanding and valuable information for pepper breeding programs in the future.

Association between daily consumption of spicy food and bone mineral density in middle-aged and older adults: a cross-sectional study

Background: Many studies have reported the effects of spicy food on human health, but no studies have been conducted on the impact of long-term spicy food consumption on bone mineral density (BMD). This study aimed to investigate the impact of daily consumption of spicy food on BMD in the population aged 50 years and older. Methods: This cross-sectional study was conducted from 2020 to 2022 in Jiangxi Province, China. This study investigated the differences in BMD between non-consumers and daily spicy food consumers in adults aged 50-85 years. A multiple linear regression model was used to investigate the association between spicy food consumption and BMD of the total lumbar spine (LS), femoral neck (FN), and total hip, as well as biochemical markers of bone metabolism (BMBM) levels. Results: The results showed that daily consumption of spicy food was negatively associated with total LS BMD (β = -0.013, P = 0.015). Subgroup analyses showed this negative association was more pronounced among smokers and drinkers compared to non-smokers (β: -0.006 vs. -0.042; P for interaction <0.05) and non-drinkers (β: -0.004 vs. -0.037; P for interaction <0.05). In addition, according to the daily frequency of spicy food consumption, the daily spicy food consumers were categorized into one meal per day, two meals per day, and three meals per day groups. Further analysis revealed that the negative association between spicy food and total LS BMD was progressively stronger as the frequency of daily consumption of spicy food increased (P for trend <0.05). For BMBM, daily consumption of spicy food was positively associated with serum PINP levels and negatively associated with serum Ca and serum Mg levels. Conclusions: Our study suggested that daily consumption of spicy food was associated with lower LS BMD in middle-aged and older Chinese adults, and this association was more pronounced in the smoking and drinking populations. The adverse effects of spicy food on LS BMD become progressively stronger with increasing frequency of daily consumption of spicy food. In addition, daily consumption of spicy food was associated with higher PINP levels and lower serum Ca and Mg levels.

Genetic tapestry of Capsicum fruit colors: a comparative analysis of four cultivated species

KEY MESSAGE

Genome-wide association study of color spaces across the four cultivated Capsicum spp. revealed a shared set of genes influencing fruit color, suggesting mechanisms and pathways across Capsicum species are conserved during the speciation. Notably, Cytochrome P450 of the carotenoid pathway, MYB transcription factor, and pentatricopeptide repeat-containing protein are the major genes responsible for fruit color variation across the Capsicum species. Peppers (Capsicum spp.) rank among the most widely consumed spices globally. Fruit color, serving as a determinant for use in food colorants and cosmeceuticals and an indicator of nutritional contents, significantly influences market quality and price. Cultivated Capsicum species display extensive phenotypic diversity, especially in fruit coloration. Our study leveraged the genetic variance within four Capsicum species (Capsicum baccatum, Capsicum chinense, Capsicum frutescens, and Capsicum annuum) to elucidate the genetic mechanisms driving color variation in peppers and related Solanaceae species. We analyzed color metrics and chromatic attributes (Red, Green, Blue, L*, a*, b*, Luminosity, Hue, and Chroma) on samples cultivated over six years (2015-2021). We resolved genomic regions associated with fruit color diversity through the sets of SNPs obtained from Genotyping by Sequencing (GBS) and genome-wide association study (GWAS) with a Multi-Locus Mixed Linear Model (MLMM). Significant SNPs with FDR correction were identified, within the Cytochrome P450, MYB-related genes, Pentatricopeptide repeat proteins, and ABC transporter family were the most common among the four species, indicating comparative evolution of fruit colors. We further validated the role of a pentatricopeptide repeat-containing protein (Chr01:31,205,460) and a cytochrome P450 enzyme (Chr08:45,351,919) via competitive allele-specific PCR (KASP) genotyping. Our findings advance the understanding of the genetic underpinnings of Capsicum fruit coloration, with developed KASP assays holding potential for applications in crop breeding and aligning with consumer preferences. This study provides a cornerstone for future research into exploiting Capsicum's diverse fruit color variation.

Small but strong: herbivory by sap-feeding insect reduces plant progeny growth but enhances direct and indirect anti-herbivore defenses

The transmission of resistance traits to herbivores across subsequent generations is an important strategy employed by plants to enhance their fitness in environments with high herbivore pressure. However, our understanding of the impact of maternal herbivory on direct and indirect induced chemical defenses of progeny, as well as the associated costs, is currently limited to herbivory by leaf-chewing insects. In this study, we investigated the transgenerational effects of a sap-feeding insect, the green peach aphid Myzus persicae, on direct and indirect chemical defenses of bell pepper plants (Capsicum annuum), and whether the effects entail costs to plant growth. Aphid herbivory on parental plants led to a reduced number of seeds per fruit, which exhibited lower germination rates and produced smaller seedlings compared to those from non-infested parental plants. In contrast, the progeny of aphid-infested plants were less preferred as hosts by aphids and less suitable than the progeny of non-infested plants. This enhanced resistance in the progeny of aphid-infested plants coincided with elevated levels of both constitutive and herbivore-induced total phenolic compounds, compared to the progeny of non-infested plants. Furthermore, the progeny of aphid-infested plants emitted herbivore-induced plant volatiles (HIPVs) that were more attractive to the aphid parasitoid Aphidius platensis than those emitted by the progeny of non-infested plants. Our results indicate that herbivory by sap-feeding insect induces transgenerational resistance on progeny bell pepper plants, albeit at the expense of vegetative growth.

Evolutionary relationships, hybridization and diversification under domestication of the locoto chile (Capsicum pubescens) and its wild relatives

Patterns of genetic variation in crops are the result of multiple processes that have occurred during their domestication and improvement, and are influenced by their wild progenitors that often remain understudied. The locoto chile, Capsicum pubescens, is a crop grown mainly in mid-highlands of South-Central America. This species is not known from the wild and exists only as a cultigen. The evolutionary affinities and exact origin of C. pubescens have still not been elucidated, with hypotheses suggesting its genetic relatedness and origin to two wild putative ancestral Capsicum species from the Central Andes, C. eximium and C. cardenasii. In the current study, RAD-sequencing was applied to obtain genome-wide data for 48 individuals of C. pubescens and its wild allies representing different geographical areas. Bayesian, Maximum Likelihood and coalescent-based analytical approaches were used to reconstruct population genetic patterns and phylogenetic relationships of the studied species. The results revealed that C. pubescens forms a well-defined monotypic lineage closely related to wild C. cardenasii and C. eximium, and also to C. eshbaughii. The primary lineages associated with the diversification under domestication of C. pubescens were also identified. Although direct ancestor-descendant relationship could not be inferred within this group of taxa, hybridization events were detected between C. pubescens and both C. cardenasii and C. eximium. Therefore, although hybrid origin of C. pubescens could not be inferred, gene flow involving its wild siblings was shown to be an important factor contributing to its contemporary genetic diversity. The data allowed for the inference of the center of origin of C. pubescens in central-western Bolivia highlands and for better understanding of the dynamics of its gene pool. The results of this study are essential for germplasm conservation and breeding purposes, and provide excellent basis for further research of the locoto chile and its wild relatives.

Genome-Wide Analysis of C-Repeat Binding Factor Gene Family in Capsicum baccatum and Functional Exploration in Low-Temperature Response

Capsicum baccatum is a close relative of edible chili peppers (Capsicum annuum) with high economic value. The CBF gene family plays an important role in plant stress resistance physiology. We detected a total of five CBF genes in the C. baccatum genome-wide sequencing data. These genes were scattered irregularly across four chromosomes. The genes were categorized into three groupings according to their evolutionary relationships, with genes in the same category showing comparable principles for motif composition. The 2000 bp upstream of CbCBF contains many resistance-responsive elements, hormone-responsive elements, and transcription factor binding sites. These findings emphasize the crucial functions of these genes in responding to challenging conditions and physiological regulation. Analysis of tissue-specific expression revealed that CbCBF3 exhibited the greatest level of expression among all tissues. Under conditions of low-temperature stress, all CbCBF genes exhibited different levels of responsiveness, with CbCBF3 showing a considerable up-regulation after 0.25 h of cold stress, indicating a high sensitivity to low-temperature response. The importance of the CbCBF3 gene in the cold response of C. baccatum was confirmed by the use of virus-induced gene silencing (VIGS) technology, as well as the prediction of its protein interaction network. To summarize, this study conducts a thorough bioinformatics investigation of the CbCBF gene family, showcases the practicality of employing VIGS technology in C. baccatum, and confirms the significance of the CbCBF3 gene in response to low temperatures. These findings provide significant references for future research on the adaptation of C. baccatum to low temperatures.

Repeated loss of the ability of a wild pepper disease resistance gene to function at high temperatures suggests that thermoresistance is a costly trait

Specificity in plant-pathogen gene-for-gene (GFG) interactions is determined by the recognition of pathogen proteins by the products of plant resistance (R) genes. The evolutionary dynamics of R genes in plant-virus systems is poorly understood. We analyse the evolution of the L resistance locus to tobamoviruses in the wild pepper Capsicum annuum var. glabriusculum (chiltepin), a crop relative undergoing incipient domestication. The frequency, and the genetic and phenotypic diversity, of the L locus was analysed in 41 chiltepin populations under different levels of human management over its distribution range in Mexico. The frequency of resistance was lower in Cultivated than in Wild populations. L-locus genetic diversity showed a strong spatial structure with no isolation-by-distance pattern, suggesting environment-specific selection, possibly associated with infection by the highly virulent tobamoviruses found in the surveyed regions. L alleles differed in recognition specificity and in the expression of resistance at different temperatures, broad-spectrum recognition of P0  + P1 pathotypes and expression above 32°C being ancestral traits that were repeatedly lost along L-locus evolution. Overall, loss of resistance co-occurs with incipient domestication and broad-spectrum resistance expressed at high temperatures has apparent fitness costs. These findings contribute to understand the role of fitness trade-offs in plant-virus coevolution.

Expression of alcohol acyltransferase is a potential determinant of fruit volatile ester variations in Capsicum

KEY MESSAGE

The transcript level of alcohol acyltransferase 1 (AAT1) may be the main factor influencing the variations in volatile esters that characterizing the fruity/exotic aroma of pepper fruit. Volatile esters are key components for characterizing the fruity/exotic aroma of pepper (Capsicum spp.) fruit. In general, the volatile ester content in the fruit is the consequence of a delicate balance between their synthesis by alcohol acyltransferases (AATs) and degradation by carboxylesterases (CXEs). However, the precise role of these families of enzymes with regard to volatile ester content remains unexplored in Capsicum. In this study, we found that the volatile ester content was relatively low in C. annuum and much higher in C. chinense, particularly in pungent varieties. Additionally, fruits collected from multiple non-pungent C. chinense varieties, which harbor loss-of-function mutations in capsaicinoid biosynthetic genes, acyltransferase (Pun1), putative aminotransferase (pAMT), or putative ketoacyl-ACP reductase (CaKR1) were analyzed. The volatile ester contents of non-pungent C. chinense varieties (pamt/pamt) were equivalent to those of pungent varieties, but their levels were significantly lower in non-pungent NMCA30036 (pun12/pun12) and C. chinense (Cakr1/Cakr1) varieties. Multiple AAT-like sequences were identified from the pepper genome sequences, whereas only one CXE-like sequence was identified. Among these, AAT1, AAT2, and CXE1 were isolated from fruits of C. chinense and C. annuum. Gene expression analysis revealed that the AAT1 transcript level is a potential determinant of fruit volatile ester variations in Capsicum. Furthermore, enzymatic assays demonstrated that AAT1 is responsible for the biosynthesis of volatile esters in pepper fruit. Identification of a key gene for aroma biosynthesis in pepper fruit will provide a theoretical basis for the development of molecular tools for flavor improvement.

Fluctuation of ecological niches and geographic range shifts along chile pepper's domestication gradient

Domestication is an ongoing well-described process. However, while many have studied the changes domestication causes in plant genetics, few have explored its impact on the portion of the geographic landscape in which the plants exist. Therefore, the goal of this study was to understand how the process of domestication changed the geographic space suitable for chile pepper (Capsicum annuum) in its center of origin (domestication). C. annuum is a major crop species globally whose center of domestication, Mexico, has been well-studied. It provides a unique opportunity to explore the degree to which ranges of different domestication classes diverged and how these ranges might be altered by climate change. To this end, we created ecological niche models for four domestication classes (wild, semiwild, landrace, modern cultivar) based on present climate and future climate scenarios for 2050, 2070, and 2090. Considering present environment, we found substantial overlap in the geographic niches of all the domestication classes. Yet, environmental and geographic aspects of the current ranges did vary among classes. Wild and commercial varieties could grow in desert conditions, while landraces could not. With projections into the future, habitat was lost asymmetrically, with wild, semiwild, and landraces at greater risk of territorial declines than modern cultivars. Further, we identified areas where future suitability overlap between landraces and wilds is expected to be lost. While range expansion is widely associated with domestication, we found little support of a constant niche expansion (either in environmental or geographical space) throughout the domestication gradient in chile peppers in Mexico. Instead, particular domestication transitions resulted in loss, followed by capturing or recapturing environmental or geographic space. The differences in environmental characterization among domestication gradient classes and their future potential range shifts increase the need for conservation efforts to preserve landraces and semiwild genotypes.

Edible flora in pre-Columbian Caribbean coprolites: Expected and unexpected data

Coprolites, or mummified feces, are valuable sources of information on ancient cultures as they contain ancient DNA (aDNA). In this study, we analyzed ancient plant DNA isolated from coprolites belonging to two pre-Columbian cultures (Huecoid and Saladoid) from Vieques, Puerto Rico, using shotgun metagenomic sequencing to reconstruct diet and lifestyles. We also analyzed DNA sequences of putative phytopathogenic fungi, likely ingested during food consumption, to further support dietary habits. Our findings show that pre-Columbian Caribbean cultures had a diverse diet consisting of maize (Zea mays), sweet potato (Ipomoea batatas), chili peppers (Capsicum annuum), peanuts (Arachis spp.), papaya (Carica papaya), tomato (Solanum lycopersicum) and, very surprisingly cotton (Gossypium barbadense) and tobacco (Nicotiana sylvestris). Modelling of putative phytopathogenic fungi and plant interactions confirmed the potential consumption of these plants as well as edible fungi, particularly Ustilago spp., which suggest the consumption of maize and huitlacoche. These findings suggest that a variety of dietary, medicinal, and hallucinogenic plants likely played an important role in ancient human subsistence and societal customs. We compared our results with coprolites found in Mexico and the United States, as well as present-day faeces from Mexico, Peru, and the United States. The results suggest that the diet of pre-Columbian cultures resembled that of present-day hunter-gatherers, while agriculturalists exhibited a transitional state in dietary lifestyles between the pre-Columbian cultures and larger scale farmers and United States individuals. Our study highlights differences in dietary patterns related to human lifestyles and provides insight into the flora present in the pre-Columbian Caribbean area. Importantly, data from ancient fecal specimens demonstrate the importance of ancient DNA studies to better understand pre-Columbian populations.

Volatile Organic Compounds Produced by Kosakonia cowanii Cp1 Isolated from the Seeds of Capsicum pubescens R & P Possess Antifungal Activity

The Kosakonia cowanii Cp1 strain was isolated from seeds of Capsicum pubescens R. & P. cultivated in Michoacan, Mexico. Genetic and ecological role analyses were conducted for better characterization. The results show that genome has a length of 4.7 Mbp with 56.22% G + C and an IncF plasmid of 128 Kbp with 52.51% G + C. Furthermore, pathogenicity test revealed nonpathogenic traits confirmed by the absence of specific virulence-related genes. Interestingly, when fungal inhibitory essays were carried out, the bacterial synthesis of volatile organic compounds (VOCs) with antifungal activity showed that Sclerotinia sp. and Rhizoctonia solani were inhibited by 87.45% and 77.24%, respectively. Meanwhile, Sclerotium rolfsii, Alternaria alternata, and Colletotrichum gloeosporioides demonstrated a mean radial growth inhibition of 52.79%, 40.82%, and 55.40%, respectively. The lowest inhibition was by Fusarium oxysporum, with 10.64%. The VOCs' characterization by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) revealed 65 potential compounds. Some of the compounds identified with high relative abundance were ketones (22.47%), represented by 2-butanone, 3-hydroxy (13.52%), and alcohols (23.5%), represented by ethanol (5.56%) and 1-butanol-3-methyl (4.83%). Our findings revealed, for the first time, that K. cowanii Cp1 associated with C. pubescens seeds possesses potential traits indicating that it could serve as an effective biocontrol.

Genomes of cultivated and wild Capsicum species provide insights into pepper domestication and population differentiation

Pepper (Capsicum spp.) is one of the earliest cultivated crops and includes five domesticated species, C. annuum var. annuum, C. chinense, C. frutescens, C. baccatum var. pendulum and C. pubescens. Here, we report a pepper graph pan-genome and a genome variation map of 500 accessions from the five domesticated Capsicum species and close wild relatives. We identify highly differentiated genomic regions among the domesticated peppers that underlie their natural variations in flowering time, characteristic flavors, and unique resistances to biotic and abiotic stresses. Domestication sweeps detected in C. annuum var. annuum and C. baccatum var. pendulum are mostly different, and the common domestication traits, including fruit size, shape and pungency, are achieved mainly through the selection of distinct genomic regions between these two cultivated species. Introgressions from C. baccatum into C. chinense and C. frutescens are detected, including those providing genetic sources for various biotic and abiotic stress tolerances.

Spice-Derived Phenolic Compounds: Potential for Skin Cancer Prevention and Therapy

Skin cancer is a condition characterized by the abnormal growth of skin cells, primarily caused by exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. Different types of skin cancer include melanoma, basal cell carcinoma, and squamous cell carcinoma. Despite the advancements in targeted therapies, there is still a need for a safer, highly efficient approach to preventing and treating cutaneous malignancies. Spices have a rich history dating back thousands of years and are renowned for their ability to enhance the flavor, taste, and color of food. Derived from various plant parts like seeds, fruits, bark, roots, or flowers, spices are important culinary ingredients. However, their value extends beyond the culinary realm. Some spices contain bioactive compounds, including phenolic compounds, which are known for their significant biological effects. These compounds have attracted attention in scientific research due to their potential health benefits, including their possible role in disease prevention and treatment, such as cancer. This review focuses on examining the potential of spice-derived phenolic compounds as preventive or therapeutic agents for managing skin cancers. By compiling and analyzing the available knowledge, this review aims to provide insights that can guide future research in identifying new anticancer phytochemicals and uncovering additional mechanisms for combating skin cancer.

Detection of Chili Foreign Objects Using Hyperspectral Imaging Combined with Chemometric and Target Detection Algorithms

Chilies undergo multiple stages from field production to reaching consumers, making them susceptible to contamination with foreign materials. Visually similar foreign materials are difficult to detect manually or using color sorting machines, which increases the risk of their presence in the market, potentially affecting consumer health. This paper aims to enhance the detection of visually similar foreign materials in chilies using hyperspectral technology, employing object detection algorithms for fast and accurate identification and localization to ensure food safety. First, the samples were scanned using a hyperspectral camera to obtain hyperspectral image information. Next, a spectral pattern recognition algorithm was used to classify the pixels in the images. Pixels belonging to the same class were assigned the same color, enhancing the visibility of foreign object targets. Finally, an object detection algorithm was employed to recognize the enhanced images and identify the presence of foreign objects. Random forest (RF), support vector machine (SVM), and minimum distance classification algorithms were used to enhance the hyperspectral images of the samples. Among them, RF algorithm showed the best performance, achieving an overall recognition accuracy of up to 86% for randomly selected pixel samples. Subsequently, the enhanced targets were identified using object detection algorithms including R-CNN, Faster R-CNN, and YoloV5. YoloV5 exhibited a recognition rate of over 96% for foreign objects, with the shortest detection time of approximately 12 ms. This study demonstrates that the combination of hyperspectral imaging technology, spectral pattern recognition techniques, and object detection algorithms can accurately and rapidly detect challenging foreign objects in chili peppers, including red stones, red plastics, red fabrics, and red paper. It provides a theoretical reference for online batch detection of chili pepper products, which is of significant importance for enhancing the overall quality of chili pepper products. Furthermore, the detection of foreign objects in similar particulate food items also holds reference value.

Plant domestication and agricultural ecologies

Plant life defines the environments to which animals adapt and provides the basis of food webs. This was equally true for hunter-gatherer economies of ancestral humans, yet through the domestication of plants and the creation of agricultural ecologies based around them, human societies transformed vegetation and transported plant taxa into new geographical regions. These human-plant interactions ultimately co-evolved, increasing human population densities, technologies of farming, and the diversification of landraces and crop complexes. Research in archaeology on preserved plant remains (archaeobotany) and on the genomes of crops, including ancient genomes, has transformed our scientific understanding of the complex relationships between humans and plants that are entailed by domestication. Key realizations of recent research include the recognition that: the co-evolution of domesticates and cultures was protracted, the adaptations of plant populations were unintended results of human economies rather than intentional breeding, domestication took place in dozens of world regions involving different crops and cultures, and convergent evolution can be recognized among cropping types - such as among seed crops, tuber crops, and fruit trees. Seven general domestication pathways can be defined for plants. Lessons for the present-day include: the importance of diversity in the past; genetic diversity within species has the potential to erode over time, but also to be rescued through processes of integration; similarly, diversification within agricultural ecosystems has undergone processes of decline, including marginalised, lost and 'forgotten' crops, as well as processes of renewal resulting from trade and human mobility that brought varied crops and varieties together.

Capsaicin Ameliorates the Cyclophosphamide-Induced Cardiotoxicity by Inhibiting Free Radicals Generation, Inflammatory Cytokines, and Apoptotic Pathway in Rats

Cyclophosphamide is an antineoplastic agent that has a broad range of therapeutic applications; however, it has numerous side effects, including cardiotoxicity. Furthermore, chili peppers contain a substance called capsaicin, having antioxidant and anti-inflammatory effects. Thus, this research paper focuses on the potential mechanism of capsaicin’s cardioprotective activity against cyclophosphamide-induced cardiotoxicity by measuring the expression of oxidative and inflammatory marker such as interleukins and caspases. The following groups of rats were randomly assigned: only vehicle given for 6 days (control group); cyclophosphamide 200 mg/kg intraperitoneal on 4th day only (positive control group); capsaicin 10 mg/kg orally given for 6 days followed by cyclophosphamide 200 mg/kg on 4th day of treatment; capsaicin 20 mg/kg orally for six days followed by cyclophosphamide 200 mg/kg on 4th day of treatment; and maximum amount of capsaicin alone (20 mg/kg) orally for six days. Using ELISA kits, it was found that the cyclophosphamide administration significantly increased the levels of lactate dehydrogenase, troponin-I (cardiac cell damage marker), lipid peroxidation, triglyceride, interleukin-6, tumor necrosis factor-alpha, and caspase 3. However, it markedly reduced the antioxidant enzymes catalase and glutathione levels. Both doses of capsaicin could reverse cardiac cell damage markers, as shown by a significant decline in (lactate dehydrogenase and troponin-I). In addition, capsaicin significantly reduced the cytokine levels (interleukin-6 and tumor necrosis factor-alpha), caspase 3, lipid peroxidation, and triglycerides. However, capsaicin treatment significantly raised the antioxidant content of enzymes such as glutathione and catalase. The capsaicin-treated group restored the oxidative parameter’s imbalance and generated considerable protection against cardiomyocyte harm from cyclophosphamide in male Wistar rats. These protective effects might be beneficial against the negative impacts of cyclophosphamide when used to treat cancer and immune-mediated diseases.

Multiple domestication events explain the origin of Gossypium hirsutum landraces in Mexico

Several Mesoamerican crops constitute wild-to-domesticated complexes generated by multiple initial domestication events, and continuous gene flow among crop populations and between these populations and their wild relatives. It has been suggested that the domestication of cotton (Gossypium hirsutum) started in the northwest of the Yucatán Peninsula, from where it spread to other regions inside and outside of Mexico. We tested this hypothesis by assembling chloroplast genomes of 23 wild, landraces, and breeding lines (transgene-introgressed and conventional). The phylogenetic analysis showed that the evolutionary history of cotton in Mexico involves multiple events of introgression and genetic divergence. From this, we conclude that Mexican landraces arose from multiple wild populations. Our results also revealed that their structural and functional chloroplast organizations had been preserved. However, genetic diversity decreases as a consequence of domestication, mainly in transgene-introgressed (TI) individuals (π = 0.00020, 0.00001, 0.00016, 0, and 0, of wild, TI-wild, landraces, TI-landraces, and breeding lines, respectively). We identified homologous regions that differentiate wild from domesticated plants and indicate a relationship among the samples. A decrease in genetic diversity associated with transgene introgression in cotton was identified for the first time, and our outcomes are therefore relevant to both biosecurity and agrobiodiversity conservation.

Population structure in diverse pepper (Capsicum spp.) accessions

BACKGROUND

Peppers, bell and chile, are a culturally and economically important worldwide. Domesticated Capsicum spp. are distributed globally and represent a complex of valuable genetic resources.

OBJECTIVES

Explore population structure and diversity in a collection of 467 peppers representing eight species, spanning the spectrum from highly domesticated to wild using 22,916 SNP markers distributed across the twelve chromosomes of pepper.

RESULTS

These species contained varied levels of genetic diversity, which also varied across chromosomes; the species also differ in the size of genetic bottlenecks they have experienced. We found that levels of diversity negatively correlate to levels of domestication, with the more diverse being the least domesticated.

Spicy Food and Chili Peppers and Multiple Health Outcomes: Umbrella Review

Spicy foods and chili peppers contain the primary ingredient capsaicin, which has potential health benefits. However, their efficacy in some health outcomes is also fiercely disputed, and some side effects have been confirmed. To assess the quality and strength of the associations between spicy food and chili pepper consumption and different health outcomes. An umbrella review is performed in humans. Eleven systematic reviews and meta-analyses with a total of 27 findings are identified. The health effect of consuming spicy food and chili peppers is unclear. Furthermore, the characteristics and context of different world regions and populations should be carefully considered. Direct correlations exist in esophageal cancer, gastric cancer, and gallbladder cancer. However, negative connections are reported in metabolism, mortality, and cardiovascular disease. Dose-response analysis reveals a significant nonlinear relationship between gastric cancer risk and capsaicin intake. The consumption of spicy foods and chili peppers is typically safe. However, high-quality proof is available to confirm this conclusion.

Tracing Back the History of Pepper (Capsicum annuum) in the Iberian Peninsula from a Phenomics Point of View

The Iberian Peninsula was the place where pepper (Capsicum annuum) entered Europe and dispersed to other continents but was also an important secondary center for its diversification. The current work evaluated the phenotypic diversity existing in this region and investigated how that evolved from Capsicum native areas (Mexico and Andean Region). For that purpose, the high-throughput phenotyping tool Tomato Analyzer was employed. Descriptors related to size and shape were the most distinctive among fruit types, reflecting a broad diversity for Iberian peppers. These traits likely reflected those suffering from more intensive human selections, driving the worldwide expansion of C. annuum. Iberian peppers maintained close proximity to the American accessions in terms of fruit phenomics. The highest similarities were observed for those coming from the southeastern edge of the Peninsula, while northwestern accessions displayed more significant differences. Common fruit traits (small, conical) suggested that Portuguese and Spanish landraces may have arisen from an ancient American population that entered the south of Spain and promptly migrated to the central and northern territories, giving rise to larger, elongated, and blocky pods. Such lineages would be the result of adaptations to local soil-climate factors prevailing in different biogeographic provinces.

Does Domestication Affect Structural and Functional Leaf Epidermal Traits? A Comparison between Wild and Cultivated Mexican Chili Peppers (Capsicum annuum)

During domestication, lineages diverge phenotypically and genetically from wild relatives, particularly in preferred traits. In addition to evolutionary divergence in selected traits, other fitness-related traits that are unselected may change in concert. For instance, the selection of chili pepper fruits was not intended to change the structure and function of the leaf epidermis. Leaf stomata and trichome densities play a prominent role in regulating stomatal conductance and resistance to herbivores. Here, we assessed whether domestication affected leaf epidermis structure and function in Capsicum annuum. To do this, we compared leaf stomata and trichome densities in six cultivated varieties of Mexican Capsicum annuum and their wild relative. We measured stomatal conductance and resistance to herbivores. Resistance to (defense against) herbivores was measured as variation in the herbivory rate and larvae mortality of Spodoptera frugiperda fed with leaves of wild and cultivated plants. As expected, the different varieties displayed low divergence in stomatal density and conductance. Leaf trichome density was higher in the wild relative, but variation was not correlated with the herbivory rate. In contrast, a higher mortality rate of S. frugiperda larvae was recorded when fed with the wild relative and two varieties than larvae fed with four other varieties. Overall, although domestication did not aim at resistance to herbivores, this evolutionary process produced concerted changes in defensive traits.

Diversification of chiles (Capsicum, Solanaceae) through time and space: New insights from genome-wide RAD-seq data

Capsicum L. encompasses 43 American species, including the five domesticated worldwide consumed sweet and hot chiles. This study presents new, updated and age-calibrated phylogenetic hypothesis on the genus evolution incorporating nearly all currently accepted Capsicum species. A new model of spatial diversification of Capsicum is proposed based on analyses of several thousands of genome-wide RAD-seq derived SNPs. Maximum likelihood approaches were used to reconstruct phylogenies and to estimate dates of all major splits. Ancestral ranges were inferred and diversification events were modeled in a time frame using a Bayesian approach. Nine clades corresponding to genetically and (mostly) geographically well-defined lineages, which diversified starting around mid-upper Miocene, were recovered with strong support. The Northern and Central Andes were inferred to represent the most likely ancestral range of the genus Capsicum. A few early vicariant and dispersal events were estimated to have driven the geographic divergence of the main Capsicum clades. Each lineage was inferred to have diversified within a distinct region of South America and expanded geographically to different extent. Extant species diversification was inferred to have begun at the beginning of Pliocene and continued through the Pleistocene. The Central Andes, represented mainly by the territory of present-day Bolivia, were proposed to play a central role in the diversification of lineages comprising domesticated capsicums and their wild allies. The genome-wide approach allowed for high resolution and support of deep phylogenetic nodes providing novel insights into the affinities of major lineages and clades as well as on the geographic expansion of Capsicum. This study provides the first dated evolutionary history of the genus encompassing most of the chile species diversity.

Viromes of 15 Pepper (Capsicum annuum L.) Cultivars

Pepper (Capsicum annuum L.) plants produce berry fruits that are used as spices. Here, we examined the viromes of 15 pepper cultivars through RNA sequencing. We obtained 1,325 virus-associated contigs derived from 8 virus species. Bean broad wilt virus 2 (BBWV2) and cucumber mosaic virus (CMV) were identified as the major viruses infecting pepper plants, followed by potato virus Y, bell pepper endornavirus, and hot pepper endornavirus. The proportion of viral reads in each transcriptome ranged from 0.04% to 24.5%. BBWV2 was the dominant virus in seven cultivars, whereas CMV was dominant in five cultivars. All the bell pepper cultivars showed severe viral disease symptoms, whereas the commercially developed hot pepper cultivars were asymptomatic or had mild symptoms. In addition, 111 complete viral segments were obtained from 7 viruses. Based on the obtained viral genomes, the genetic relationship between the identified viruses and quasispecies of BBWV2 and CMV in each pepper plant was determined. Newly designed primers for nine viruses confirmed the results of RNA sequencing. Taken together, this study, for the first time, provides a comprehensive overview of viromes in 15 major pepper cultivars through RNA sequencing.

Peppers in Diet: Genome-Wide Transcriptome and Metabolome Changes in Drosophila melanogaster

The habanero pepper (Capsicum chinense) is an increasingly important spice and vegetable crop worldwide because of its high capsaicin content and pungent flavor. Diets supplemented with the phytochemicals found in habanero peppers might cause shifts in an organism's metabolism and gene expression. Thus, understanding how these interactions occur can reveal the potential health effects associated with such changes. We performed transcriptomic and metabolomic analyses of Drosophila melanogaster adult flies reared on a habanero pepper diet. We found 539 genes/59 metabolites that were differentially expressed/accumulated in flies fed a pepper versus control diet. Transcriptome results indicated that olfactory sensitivity and behavioral responses to the pepper diet were mediated by olfactory and nutrient-related genes including gustatory receptors (Gr63a, Gr66a, and Gr89a), odorant receptors (Or23a, Or59a, Or82a, and Orco), and odorant-binding proteins (Obp28a, Obp83a, Obp83b, Obp93a, and Obp99a). Metabolome analysis revealed that campesterol, sitosterol, and sucrose were highly upregulated and azelaic acid, ethyl phosphoric acid, and citric acid were the major metabolites downregulated in response to the habanero pepper diet. Further investigation by integration analysis between transcriptome and metabolome data at gene pathway levels revealed six unique enriched pathways, including phenylalanine metabolism; insect hormone biosynthesis; pyrimidine metabolism; glyoxylate, and dicarboxylate metabolism; glycine, serine, threonine metabolism; and glycerolipid metabolism. In view of the transcriptome and metabolome findings, our comprehensive analysis of the response to a pepper diet in Drosophila have implications for exploring the molecular mechanism of pepper consumption.

Chili Pepper Jojutla Morelos (Capsicum annuum L.), CJ-2018: A Variety Resistant to Bactericera cockerelli

Chili pepper is a vegetable of worldwide economic and gastronomic importance. The psyllid, Bactericera cockerelli, is an economically important pest in this crop, causing considerable losses in its production. Currently, the application of insecticides is the main way to control B. cockerelli. However, the use of varieties resistant to this insect is a viable alternative for its control and management. In this work, the oviposition rate, development, and survival of B. cockerelli in two native varieties of chili were evaluated. Choice and non-choice trials showed that the B. cockerelli oviposition was reduced on CJ-2018 by 92.17 and 80.18%, respectively, compared to the control. In CM-334, the insect showed a behavior similar to the control in the non-choice test, while in the choice test it laid more eggs on CM-334 compared to the control. The development and survival assay showed that only 1.33% of the eggs managed to reach the adult stage on CJ-2018. In contrast, on CM-334 the survival of B. cockerelli was similar to the control. These results suggest that CJ-2018 presented a resistance based on antixenosis and antibiosis against B. cockerelli.

Capsicum annuum with causal allele of hybrid weakness is prevalent in Asia

Reproductive isolation, including hybrid weakness, plays an important role in the formation of species. Hybrid weakness in Capsicum, the cessation of plant growth, is caused by two complementary dominant genes, A from C. chinense or C. frutescens and B from C. annuum. In the present study, we surveyed whether 94 C. annuum accessions had B or b alleles by crossing with C. chinense having the A allele. Of the 94 C. annuum accessions, five had the B allele, three of which were native to Latin America and two were native to Asia. When combined with previous studies, the percentage of B carriers was 41% in Japan, 13% in Asia excluding Japan, 6% in Latin America, and 0% in Europe and Africa. In addition, 48 accessions of C. annuum from various countries were subjected to SSR analysis. Clades with high percentages of B-carriers were formed in the phylogenetic trees. In the principal coordinate analysis, most B-carriers were localized in a single group, although the group also included b-carriers. Based on these results, we presumed that the B allele was acquired in some C. annuum lines in Latin America, and B-carriers were introduced to the world during the Age of Discovery, as along with the b-carriers.

Genetic diversity, gene flow, and differentiation among wild, semiwild, and landrace chile pepper (Capsicum annuum) populations in Oaxaca, Mexico

PREMISE

Capsicum annuum (Solanaceae) was originally domesticated in Mexico, where wild (C. annuum var. glabriusculum) and cultivated (C. annuum var. annuum) chile pepper populations (>60 landraces) are common, and wild-resembling individuals (hereafter semiwild) grow spontaneously in anthropogenic environments. Here we analyze the role of elevation and domestication gradients in shaping the genetic diversity in C. annuum from the state of Oaxaca, Mexico.

METHODS

We collected samples of 341 individuals from 28 populations, corresponding to wild, semiwild (C. annuum var. glabriusculum) and cultivated C. annuum, and closely related species Capsicum frutescens and C. chinense. From the genetic variation of 10 simple sequence repeat (SSR) loci, we assessed the population genetic structure, inbreeding, and gene flow through variance distribution analyses, genetic clustering, and connectivity estimations.

RESULTS

Genetic diversity (H_E ) did not differ across domestication levels. However, inbreeding coefficients were higher in semiwild and cultivated chiles than in wild populations. We found evidence for gene flow between wild populations and cultivated landraces along the coast. Genetic structure analysis revealed strong differentiation between most highland and lowland landraces.

CONCLUSIONS

Gene flow between wild and domesticated populations may be mediated by backyards and smallholder farms, while mating systems may facilitate gene flow between landraces and semiwild populations. Domestication and elevation may overlap in their influence on genetic differentiation. Lowland Gui'ña dani clustered with highland landraces perhaps due to the social history of the Zapotec peoples. In situ conservation may play an important role in preserving semiwild populations and private alleles found in landraces.

Monograph of wild and cultivated chili peppers (Capsicum L., Solanaceae)

Capsicum L. (tribe Capsiceae, Solanaceae) is an American genus distributed ranging from the southern United States of America to central Argentina and Brazil. The genus includes chili peppers, bell peppers, ajíes, habaneros, jalapeños, ulupicas and pimientos, well known for their economic importance around the globe. Within the Solanaceae, the genus can be recognised by its shrubby habit, actinomorphic flowers, distinctive truncate calyx with or without appendages, anthers opening by longitudinal slits, nectaries at the base of the ovary and the variously coloured and usually pungent fruits. The highest diversity of this genus is located along the northern and central Andes. Although Capsicum has been extensively studied and great advances have been made in the understanding of its taxonomy and the relationships amongst species, there is no monographic treatment of the genus as a whole. Based on morphological and molecular evidence studied from field and herbarium specimens, we present here a comprehensive taxonomic treatment for the genus, including updated information about morphology, anatomy, karyology, phylogeny and distribution. We recognise 43 species and five varieties, including C.mirum Barboza, sp. nov. from São Paulo State, Brazil and a new combination C.muticum (Sendtn.) Barboza, comb. nov.; five of these taxa are cultivated worldwide (C.annuumL.var.annuum, C.baccatumL.var.pendulum (Willd.) Eshbaugh, C.baccatumL.var.umbilicatum (Vell.) Hunz. & Barboza, C.chinense Jacq. and C.frutescens L.). Nomenclatural revision of the 265 names attributed to chili peppers resulted in 89 new lectotypifications and five new neotypifications. Identification keys and detailed descriptions, maps and illustrations for all taxa are provided.

Capsaicin inhibits intestinal Cl- secretion and promotes Na+ absorption by blocking TRPV4 channels in healthy and colitic mice

Although capsaicin has been studied extensively as an activator of the transient receptor potential vanilloid cation channel subtype 1 (TRPV1) channels in sensory neurons, little is known about its TRPV1-independent actions in gastrointestinal health and disease. Here, we aimed to investigate the pharmacological actions of capsaicin as a food additive and medication on intestinal ion transporters in mouse models of ulcerative colitis (UC). The short-circuit current (Isc) of the intestine from WT, TRPV1-, and TRPV4-KO mice were measured in Ussing chambers, and Ca2+ imaging was performed on small intestinal epithelial cells. We also performed Western blots, immunohistochemistry, and immunofluorescence on intestinal epithelial cells and on intestinal tissues following UC induction with dextran sodium sulfate. We found that capsaicin did not affect basal intestinal Isc but significantly inhibited carbachol- and caffeine-induced intestinal Isc in WT mice. Capsaicin similarly inhibited the intestinal Isc in TRPV1 KO mice, but this inhibition was absent in TRPV4 KO mice. We also determined that Ca2+ influx via TRPV4 was required for cholinergic signaling-mediated intestinal anion secretion, which was inhibited by capsaicin. Moreover, the glucose-induced jejunal Iscvia Na+/glucose cotransporter was suppressed by TRPV4 activation, which could be relieved by capsaicin. Capsaicin also stimulated ouabain- and amiloride-sensitive colonic Isc. Finally, we found that dietary capsaicin ameliorated the UC phenotype, suppressed hyperaction of TRPV4 channels, and rescued the reduced ouabain- and amiloride-sensitive Isc. We therefore conclude that capsaicin inhibits intestinal Cl- secretion and promotes Na+ absorption predominantly by blocking TRPV4 channels to exert its beneficial anti-colitic action.

Food and Trauma: Anthropologies of Memory and Postmemory

Much has been written about the multifaceted significance of food and eating from an anthropological perspective; the same can be said about the role of food in collective identity construction and nation building. In contrast, the nexus of food, memory, psychological trauma, and disordered eating has been less explored. The aim of this interdisciplinary article is to synthesize available knowledge on this topic by engaging with research literature in fields such as food history, anthropology, sociology, and psychiatry as well as autobiographical works, cookbooks, etc. One main section of the article focuses on the role of food and cooking in exile and refuge. Another section deals with the role of food in the aftermath of historical trauma, whereas a final section discusses various works on disordered eating in the wake of traumatic experiences. In sum, the dual nature of food and cooking-at once concrete and abstract, material and symbolic-offers an arena in which ambivalent memories of trauma can take on tangible form. The concept of postmemory may be useful in understanding how food and cooking can function both as a vehicle and as a remedy for intergenerational trauma.

Association of pepper intake with all-cause and specific cause mortality - A systematic review and meta-analysis

OBJECTIVE

To conduct a comprehensive systematic review and meta-analysis to compare mortality and other clinical outcomes associated with chili pepper (CP) consumption versus no/rare consumption of CP.

METHODS

A comprehensive search was performed using Ovid, Cochrane, Medline, EMBASE, and Scopus from inception till January 16, 2020. Observational studies and randomized controlled trials were included, while pediatric/animal studies, letters/case reports, reviews, abstracts, and book chapters were excluded. All-cause mortality was studied as the primary outcome. Cardiovascular mortality, cancer-related deaths and cerebrovascular accidents were studied as secondary outcomes.

RESULTS

From 4729 studies, four studies met the inclusion criteria. Random effects pooled analysis showed that all-cause mortality among CP consumers was lower, compared to rare/non-consumers, with a hazard ratio (HR) of 0.87 [95% CI: 0.85-0.90; p<0.0001; I 2=1%]. HR for cardiovascular mortality was 0.83 [95% CI: 0.74-0.95; p = 0.005, I 2=66%] and for cancer-related mortality as 0.92 [95% CI: 0.87-0.97; p = 0.001; I 2=0%]. However, the HR for CVA was 0.78 [95% CI: 0.56-1.09; p = 0.26; I2 =60%]. The mode and amount of CP consumption varied across the studies, and data were insufficient to design an optimal strategy guiding its intake.

CONCLUSION

Regular CP consumption was associated with significantly lower all-cause, cardiovascular, and cancer-related mortalities. However, based on current literature, it is difficult to derive a standardized approach to guide the optimal mode and amount of CP consumption. This warrants well-designed prospective studies to further investigate the potential health benefits of CP consumption.

The INRAE Centre for Vegetable Germplasm: Geographically and Phenotypically Diverse Collections and Their Use in Genetics and Plant Breeding

The French National Research Institute for Agriculture, Food and the Environment (INRAE) conserves and distributes five vegetable collections as seeds: the aubergine* (in this article the word aubergine refers to eggplant), pepper, tomato, melon and lettuce collections, together with their wild or cultivated relatives, are conserved in Avignon, France. Accessions from the collections have geographically diverse origins, are generally well-described and fixed for traits of agronomic or scientific interest and have available passport data. In addition to currently conserving over 10,000 accessions (between 900 and 3000 accessions per crop), the centre maintains scientific collections such as core collections and bi- or multi-parental populations, which have also been genotyped with SNP markers. Each collection has its own merits and highlights, which are discussed in this review: the aubergine collection is a rich source of crop wild relatives of Solanum; the pepper, melon and lettuce collections have been screened for resistance to plant pathogens, including viruses, fungi, oomycetes and insects; and the tomato collection has been at the heart of genome-wide association studies for fruit quality traits and environmental stress tolerance.

Capsaicin and TRPV1 Channels in the Cardiovascular System: The Role of Inflammation

Capsaicin is a potent agonist of the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel and is a common component found in the fruits of the genus Capsicum plants, which have been known to humanity and consumed in food for approximately 7000-9000 years. The fruits of Capsicum plants, such as chili pepper, have been long recognized for their high nutritional value. Additionally, capsaicin itself has been proposed to exhibit vasodilatory, antimicrobial, anti-cancer, and antinociceptive properties. However, a growing body of evidence reveals a vasoconstrictory potential of capsaicin acting via the vascular TRPV1 channel and suggests that unnecessary high consumption of capsaicin may cause severe consequences, including vasospasm and myocardial infarction in people with underlying inflammatory conditions. This review focuses on vascular TRPV1 channels that are endogenously expressed in both vascular smooth muscle and endothelial cells and emphasizes the role of inflammation in sensitizing the TRPV1 channel to capsaicin activation. Tilting the balance between the beneficial vasodilatory action of capsaicin and its unwanted vasoconstrictive effects may precipitate adverse outcomes such as vasospasm and myocardial infarction, especially in the presence of proinflammatory mediators.

Emerging evidence of plant domestication as a landscape-level process

The evidence from ancient crops over the past decade challenges some of our most basic assumptions about the process of domestication. The emergence of crops has been viewed as a technologically progressive process in which single or multiple localized populations adapt to human environments in response to cultivation. By contrast, new genetic and archaeological evidence reveals a slow process that involved large populations over wide areas with unexpectedly sustained cultural connections in deep time. We review evidence that calls for a new landscape framework of crop origins. Evolutionary processes operate across vast distances of landscape and time, and the origins of domesticates are complex. The domestication bottleneck is a redundant concept and the progressive nature of domestication is in doubt.

Beneficial effect of capsaicin via TRPV4/EDH signals on mesenteric arterioles of normal and colitis mice

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Capsaicin induced vasorelaxation of human colonic submucosal arterioles in vitro and in vitro.

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Capsaicin induced an endothelium-dependent vasorelaxation of human submucosal arterioles.

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Capsaicin induced an endothelium-dependent vasorelaxation of mouse mesenteric arterioles.

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Capsaicin induced vasorelaxation minily by TRPV1-mediated endothelial nitric oxide release.

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Capsaicin induced vasorelaxation mainly by TRPV4/endothelium-dependent hyperpolarization.

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Capsaicin exerted anti-colitis action in wide-type mice, but not in TRPV4 knock-out mice.

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Capsaicin rescued the impaired endothelium-dependent vasorelaxation via TRPV4/EDH pathway.

Introduction

Although capsaicin has long been used as food additive and medication worldwide, its actions on gastrointestinal tract as its most delivery pathway have not been well addressed.

Objectives

In the present study, we aimed to study GI actions of capsaicin on mesenteric arterioles in normal and colitis mice and to elucidate the underlying mechanisms.

Methods

Vasorelaxation of human submucosal arterioles and the mesenteric arterioles from wide-type (WT) mice, TRPV1^−/− and TRPV4^−/− (KO) mice were measured. The expression and function of TRPV channels in endothelial cells were examined by q-PCR, immunostaining, Ca²⁺ imaging and membrane potential measurements.

Results

Capsaicin dose-dependently induced vasorelaxation of human submucosal arterioles and mouse mesenteric arterioles in vitro and in vivo through endothelium-dependent hyperpolarization (EDH), nitric oxide (NO), and prostacyclin (PGI₂). Using TRPV1 and TRPV4 KO mice, we found that capsaicin-induced vasorelaxation was predominately through TRPV4/EDH, but marginally through TRPV1/NO/PGI₂. Capsaicin induced hyperpolarization through activation of endothelial TRPV4 channels and intermediate-conductance of Ca²⁺-activated K⁺ channels to finally stimulate vasorelaxation. Importantly, capsaicin exerted anti-colitis action by rescuing the impaired ACh-induced vasorelaxation in WT colitis mice but not in TRPV4 KO colitis mice.

Conclusions

Capsaicin increases intestinal mucosal blood perfusion to potentially prevent/treat colitis through a novel TRPV4/EDH-dependent vasorelaxation of submucosal arterioles in health and colitis. This study further supports our previous notion that TRPV4/EDH in mesenteric circulation plays a critical role in the pathogenesis of colitis.