Analysis of 207 residual pesticides in hot pepper powder using LC-MS/MS.

This study investigated the determination of 207 pesticides in hot pepper powder and found patterns of pesticide use by production from five regions, detecting a total of 50 pesticides. The LOD, LOQ and recoveries of pesticides were 0.08-2.53, 0.25-7.60 µg kg-1, and 81.0-132.1%, respectively. The Horrat values ranged from 0.07 to 1.97. A total of 50 residual pesticides were detected in 963 hot pepper powder samples. All residual pesticide levels were below the Korean maximum residue level (MRL) and the %ADI was ≤ 0.001-0.076%. Seven pesticides had a detection rate above 50% (tebuconazole, pyraclostrobin, etofenprox, flonicamid, imidacloprid, carbendazim, and flubendiamide). The region where the most pesticide types were detected was Ham-pyeong with 38 types. Tebuconazole had detection rates of > 90% in all regions. In the PCA results with factor analysis, each region shows patterns of pesticide use. Four regions focus on Aphidoidea control and one region on Colletotrichum acutatum control. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01443-6.

Comparative transcriptome analysis and Arabidopsis thaliana overexpression reveal key genes associated with cadmium transport and distribution in root of two Capsicum annuum cultivars.

The molecular mechanisms underlying high and low cadmium (Cd) accumulation in hot pepper cultivars remain unclear. In this study, comparative transcriptome analysis of root between high-Cd (J) and low-Cd (Z) cultivars was conducted under hydroponic cultivation with 0 and 0.4 mg/L Cd, respectively. The results showed that J enhanced the root uptake of Cd by elevating the expression of Nramp5 and counteracting Cd toxicity by increasing the expression of genes, such as NIR1, GLN1, and IAA9. Z reduced Cd accumulation by enhancing the cell wall lignin synthesis genes PAL, COMT, 4CL, LAC, and POD and the Cd transporters ABC, MTP1, and DTX1. Elevated expression of genes related to sulfur metabolism was observed in Z, potentially contributing to its ability to detoxify Cd. To investigate the function of CaCOMT1, an Arabidopsis thaliana overexpression line (OE-CaCOMT1) was constructed. The results revealed that OE-CaCOMT1 drastically increased the lignin content by 38-42% and reduced the translocation of Cd to the aboveground parts by 32%. This study provides comprehensive insights into the mechanisms underlying Cd accumulation in hot pepper cultivars using transcriptome analysis. Moreover, this study elucidates the critical function of CaCOMT1, providing a theoretical foundation for the production of low-Cd vegetables for food safety.

Physiological and molecular mechanisms of boron in alleviating cadmium toxicity in Capsicum annuum.

Soil cadmium (Cd) contamination threatens food safety and human health, particularly in developing countries. Previously, we have proposed that boron (B) could reduce Cd uptake and accumulation in hot peppers (Capsicum annuum) by regulating the expression of genes related to Cd transport in roots. However, only few studies have examined the role of B in plant leaves under Cd stress. It is unclear how B induces the expression of relevant genes and metabolites in hot pepper leaves and to what extent B is involved in leaf growth and Cd accumulation. The purpose of this study was to investigate the effects of B on growth and Cd accumulation in hot pepper leaves by determining physiological parameters and transcriptome sequencing. The results showed that B application significantly improved the concentration of chlorophyll a and intercellular CO2, stomatal conductance, and photosynthetic and transpiration rates by 18-41 % in Cd-stressed plants. Moreover, B enhanced Cd retention in the cell wall by upregulating the expression levels of pectin-, lignin-, and callose-related genes and improving the activity of pectin methylesterase by 30 %, resulting in an approximate 31 % increase in Cd retention in the cell wall. Furthermore, B application not only enhanced the expression levels of genes related to antioxidant enzymes (superoxide dismutase, catalase, and peroxidase) and their activities by 28-40 %, thereby counteracting Cd-induced oxidative stress, but also improved Cd chelation, sequestration, and exclusion by upregulating the expression levels of genes related to sulfur metabolism, heavy metal-associated isoprenylated plant protein (HIPP), and transporters such as vacuolar cation/proton exchanger (CAX3), metal-nicotianamine transporter (YSL), ATP-binding cassette (ABC), zinc/iron transporters (ZIP) and oxic-compound detoxification (DTX), ultimately reinforcing Cd tolerance. Together, our results suggest that B application reduces the negative effects of Cd on leaf growth, promotes photosynthesis, and decreases Cd transfer to fruits through its sequestration and retention.

Pepper Fruit Extracts Show Anti-Proliferative Activity against Tumor Cells Altering Their NADPH-Generating Dehydrogenase and Catalase Profiles.

Cancer is considered one of the main causes of human death worldwide, being characterized by an alteration of the oxidative metabolism. Many natural compounds from plant origin with anti-tumor attributes have been described. Among them, capsaicin, which is the molecule responsible for the pungency in hot pepper fruits, has been reported to show antioxidant, anti-inflammatory, and analgesic activities, as well as anti-proliferative properties against cancer. Thus, in this work, the potential anti-proliferative activity of pepper (Capsicum annuum L.) fruits from diverse varieties with different capsaicin contents (California < Piquillo < Padrón < Alegría riojana) against several tumor cell lines (lung, melanoma, hepatoma, colon, breast, pancreas, and prostate) has been investigated. The results showed that the capsaicin content in pepper fruits did not correspond with their anti-proliferative activity against tumor cell lines. By contrast, the greatest activity was promoted by the pepper tissues which contained the lowest capsaicin amount. This indicates that other compounds different from capsaicin have this anti-tumor potentiality in pepper fruits. Based on this, green fruits from the Alegría riojana variety, which has negligible capsaicin levels, was used to study the effect on the oxidative and redox metabolism of tumor cell lines from liver (Hep-G2) and pancreas (MIA PaCa-2). Different parameters from both lines treated with crude pepper fruit extracts were determined including protein nitration and protein S-nitrosation (two post-translational modifications (PTMs) promoted by nitric oxide), the antioxidant capacity, as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX), among others. In addition, the activity of the NADPH-generating enzymes glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), and NADP-isocitrate dehydrogenase (NADP-ICDH) was followed. Our data revealed that the treatment of both cell lines with pepper fruit extracts altered their antioxidant capacity, enhanced their catalase activity, and considerably reduced the activity of the NADPH-generating enzymes. As a consequence, less H2O2 and NADPH seem to be available to cells, thus avoiding cell proliferation and possibly triggering cell death in both cell lines.

Insulin-like Peptides of the Western Flower Thrips Frankliniella occidentalis and Their Mediation of Immature Development.

Insulin-like peptides (ILPs) mediate various physiological processes in insects. Specifically, ILP expression is required for immature development in different insects. The western flower thrips, Frankliniella occidentalis, is polyphagous, but its occurrence and population density vary among different hosts. This study assesses the developmental variations in the thrips through quantitative analysis of their ILP expressions. Two types of ILPs (Fo-ILP1 and Fo-ILP2) were identified from the genome of F. occidentalis, and both ILPs were predicted to have the characteristics of signal peptides and B-C-A chains linked by cysteines. A phylogenetic analysis indicates that these two ILPs in the thrips are clustered with the ILP1 of Drosophila melanogaster, suggesting their physiological roles in growth. In addition, the two ILP genes were relatively highly expressed at all feeding stages, but their expression was reduced during the nonfeeding prepupal and pupal stages. Furthermore, RNA interference of each ILP expression led to significant developmental retardation. In validating the ILP expression in the thrips' development, five different varieties of host hot peppers were assessed in a choice test, along with the immature development of F. occidentalis. The expression levels of the two ILP genes were highly correlated with variations in the immature developmental rates of different hot pepper varieties. These suggest that Fo-ILP1 and Fo-ILP2 mediate the immature development of F. occidentalis by sensing different nutritional values of hot peppers. This study is the first report on ILPs in thysanopteran insects.

Boron supplying alters cadmium retention in root cell walls and glutathione content in Capsicum annuum.

Large areas of farmland in southern China are facing environmental problems such as cadmium (Cd) contamination and boron (B) deficiency. The aim of this study was to investigate the biochemical and molecular mechanisms underlying the reduction in Cd accumulation in hot pepper (Capsicum annuum) by B application. A hydroponic experiment was conducted to compare the subcellular distribution of Cd, transcriptome profile, degree of pectin methylation, and glutathione (GSH) synthesis in the roots of hot pepper under different B and Cd conditions. Boron supply promoted root cell wall biosynthesis and pectin demethylation by upregulating related genes and increasing cell wall Cd concentration by 28%. In addition, with the application of B, the proportion of Cd in root cell walls increased from 27% to 37%. Boron supplementation upregulated sulfur metabolism-related genes but decreased cysteine and GSH contents in the roots. As a result, shoot Cd concentration decreased by 27% due to the decrease in GSH, a critical long-distance transport carrier of Cd. Consequently, B supply could reduce the uptake, translocation, and accumulation of Cd in hot pepper by retaining Cd in the root cell walls and decreasing GSH content.

Functional analysis of hot pepper ethylene responsive factor 1A in plant defense.

Ethylene-responsive factors play important roles in the biotic and abiotic stresses. Only some ERF genes from Capsicum annuum have been characterized. In the study, the CaERF1A gene is characterized in response to biotic stress. CaERF1A transcripts were induced by various plant defense-related hormone treatments. Knockdown of CaERF1A in hot pepper plants are negatively affected Tobacco mosaic virus-P0-mediated hypersensitive response cell death, resulting in reduced gene expression of pathogenesis-related genes and ethylene and jasmonic acid synthesis-related gene. Overexpressing CaERF1A transgenic plants show enhanced resistance to fungal pathogen via regulating ethylene and jasmonic acid synthesis-related gene expression. Thus, CaERF1A is a positive regulator of plant defense by modulating ethylene and jasmonic acid synthesis-related gene expressions.

Boron decreases cadmium influx into root cells of Capsicum annuum by altering cell wall components and plasmalemma permeability.

Large areas of soil are boron (B) deficient and contaminated with cadmium (Cd) in southern China. The aim of this study was to select the optimal B supply level and elucidate the underlying physiological and biochemical mechanisms to understand how B reduces Cd influx into root cells of hot pepper (Capsicum annuum). An experiment was conducted to investigate the changes in Cd accumulation with B supply. Hot pepper seedlings were grown in two nutrient solutions containing 0.05- and 0.2-mg Cd L-1 and supplied with six different B concentrations for 2 weeks. The other experiment was conducted to determine the Cd2+ flux into cells, cell wall components, antioxidative ability, and plasmalemma permeability of root tips of hot pepper exposed to 0.1-mg Cd L-1 in the presence and absence of B. The results showed that the optimal B concentration to promote plant growth and reduce Cd accumulation was 0.25 mg L-1. Moreover, B application significantly decreased Cd2+ influx into cells, increased the contents of lignin and pectin, enhanced the activities of antioxidant enzymes, reduced the production of reactive oxygen species, and decreased membrane peroxidation and permeability. Overall, boron in moderation can promote plant growth, maintain the normal structures and functions of the cell wall and membrane, and thus decrease Cd2+ influx into root cells and subsequently Cd translocation to shoots. Consequently, B is a reliable inhibitor of Cd uptake, and the functional and structural integrity of cell walls and membranes may have some relevance to reduced Cd uptake after B application.

Determination of 113 pesticides in hot pepper powder in Korea.

In five regions of Korea, a total of 963 hot pepper powder samples were analyzed for 113 pesticides and one synergist using gas chromatography-mass spectrometry. For three years, sampling was performed every producing day in production plants according to ISO 24153 : 2009 methods. The limit of detection and limit of quantification ranges were 0.17-1.46 and 0.52-4.44 µg kg-1, respectively. The recovery ranges were 62.8-128.6% when spiked with 10 and 100 µg kg-1 of pesticides. Certified reference materials, such as chlorfenapyr and indoxacarb, were used for the validation of the analytical method. In total, 21 pesticides and one synergist were detected. Six pesticides, chlorfenapyr, indoxacarb, chlorantraniliprole, cypermethrin, difenoconazole, and pendimethalin, were detected at more than 50%, and nine pesticides, cyhalothrin, fenvalerate, picoxystrobin, deltamethrin, pyridalyl, propiconazole, iprodione, prochloraz, and bifenthrin, were detected at more than 10%. All monitoring results were under the Korean maximum residue limit.

The effects of dietary hot pepper Capsicum annuum waste powder supplementation on egg production traits of Japanese quail layers / Efeitos da suplementação de pó de Capsicum annuum na dieta sobre a produção de ovos de codornas japonesas

ABSTRACT: This study was conducted to evaluate the effects of different levels of dietary hot pepper (Capsicum annuum L.) waste supplementation on egg production performance and quality in Japanese quail hens (Coturnix coturnix japonica). A total of 192, seven-week-old Japanese quail layers were divided into 4 treatment groups of similar mean weight (304±0.5 g), each comprising 12 subgroups (including 1 male and 3 females). Treatment birds were fed on experimental basal layer diet supplemented with 1, 2 or 4 g hot pepper waste powder (HPWP) per kg diet. The laying performance was determined by recording feed intake, egg weight, daily egg production, and biweekly egg quality. Results showed that HPWP supplementation to layer diet did not have any significant (P>0.05) effects on body weight and feed conversion ratio, while it had significant effects on feed intake (P<0.01), and laying egg weight, average egg weight, total egg yield (P<0.05). A 2 g HPWP supplementation resulted in the highest total egg yield (P<0.05) with quadratic effects on egg shape index (P<0.05) and albumen pH (P<0.01). According to the values in the study, the egg shape index of 2 g HPWP group was circular and; therefore, attractive to consumers. We highly recommend the non-economic value of 2 g/kg supplementation of hot pepper waste powder, especially for egg production. To conclude, HPWP can be used for quail layer diets due to its beneficial effects on egg quality since it is an economic and easy agricultural by-product obtained from red pepper paste industry waste.

RESUMO: Este estudo foi conduzido para avaliar os efeitos de diferentes níveis de suplementação de resíduos de pimenta na dieta (Capsicum annuum L.), no desempenho e na qualidade da produção de ovos em codornas japonesas (Coturnix coturnix japonica). Um total de 192 codornas japonesas com sete semanas de idade foram alocadas em 4 grupos com peso médio semelhante (304 ± 0.5 g), cada um compreendendo 12 subgrupos (incluindo 1 macho e 3 fêmeas). As aves tratadas foram alimentadas com dieta experimental basal suplementada com 1, 2 ou 4 g de pimenta em pó (HPWP) por kg de dieta. O desempenho da postura foi determinado pelo registro da ingestão de ração, peso dos ovos, produção diária de ovos e qualidade quinzenal dos ovos. Os resultados mostraram que a suplementação de HPWP à dieta não teve efeitos significativos (P> 0,05) no peso corporal e na taxa de conversão alimentar, enquanto teve efeitos significativos no consumo de ração (P <0,01) e no peso do ovo em postura, peso médio do ovo, produção total de ovos (P <0,05). Uma suplementação de 2 g de HPWP resultou na maior produção total de ovos (P <0,05) com efeitos quadráticos no índice de forma dos ovos (P <0,05) e no pH do albumen (P <0,01). De acordo com os valores do estudo, o índice de forma dos ovos de 2 g do grupo HPWP era circular e, portanto, atraente para os consumidores. É altamente recomendável o valor não-econômico de 2 g / kg de suplementação de pó de pimenta, especialmente para a produção de ovos. Para concluir, a HPWP pode ser usada para dietas de codorna devido aos seus efeitos benéficos na qualidade dos ovos, uma vez que é um subproduto agrícola obtido a partir de resíduos da indústria de pasta de pimenta vermelha de maneira econômica e fácil.

Characterization of the hot pepper (Capsicum frutescens) fruit ripening regulated by ethylene and ABA.

BACKGROUND: Ripening of fleshy fruits has been classically defined as climacteric or non-climacteric. Both types of ripening are controlled by plant hormones, notably by ethylene in climacteric ripening and by abscisic acid (ABA) in non-climacteric ripening. In pepper (Capsicum), fruit ripening has been widely classified as non-climacteric, but the ripening of the hot pepper fruit appears to be climacteric. To date, how to regulate the hot pepper fruit ripening through ethylene and ABA remains unclear. RESULTS: Here, we examined ripening of the hot pepper (Capsicum frutescens) fruit during large green (LG), initial colouring (IC), brown (Br), and full red (FR) stages. We found a peak of ethylene emission at the IC stage, followed by a peak respiratory quotient at the Br stage. By contrast, ABA levels increased slowly before the Br stage, then increased sharply and reached a maximum level at the FR stage. Exogenous ethylene promoted colouration, but exogenous ABA did not. Unexpectedly, fluridone, an inhibitor of ABA biosynthesis, promoted colouration. RNA-sequencing data obtained from the four stages around ripening showed that ACO3 and NCED1/3 gene expression determined ethylene and ABA levels, respectively. Downregulation of ACO3 and NCED1/3 expression by virus-induced gene silencing (VIGS) inhibited and promoted colouration, respectively, as evidenced by changes in carotenoid, ABA, and ethylene levels, as well as carotenoid biosynthesis-related gene expression. Importantly, the retarded colouration in ACO3-VIGS fruits was rescued by exogenous ethylene. CONCLUSIONS: Ethylene positively regulates the hot pepper fruit colouration, while inhibition of ABA biosynthesis promotes colouration, suggesting a role of ABA in de-greening. Our findings provide new insights into processes of fleshy fruit ripening regulated by ABA and ethylene, focusing on ethylene in carotenoid biosynthesis and ABA in chlorophyll degradation.

Ectopic RING zinc finger gene from hot pepper induces totally different genes in lettuce and tobacco.

Advances in molecular biology have improved crops through transferring genes from one organism to new hosts, and these efforts have raised concerns about potential unexpected outcomes. Here, we provide evidence that a gene with a specific function in one organism can yield completely different effects in a new host. CaRZFP1 is a C3HC4-type RING zinc finger protein gene previously isolated from a cDNA library for heat-stressed hot pepper. In our previous work investigating in vivo CaRZFP1 function, we transferred CaRZFP1 into tobacco; transgenic tobacco exhibited enhanced growth and tolerance to abiotic stresses. As further analysis of CaRZFP1 ectopic expression in a heterologous host plant, here we mobilized and constitutively overexpressed CaRZFP1 in lettuce. In contrast to tobacco, transgenic lettuce exhibited poorer growth and delayed flowering compared with vector-only controls. To identify genes that might be involved in this phenotypic effect, transcriptome analyses on transgenic plants of both species were performed, uncovering dozens of genes that reflect the different outcomes between tobacco and lettuce. These included protein kinase, transcriptional factor, transporter protein, hormone and metabolism-related genes, and some unannotated genes. The opposite effects of CaRZFP1 ectopic expression in lettuce and tobacco address concerns of unexpectedly different outcomes in different host species.

Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

BACKGROUND: Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. RESULTS: The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g-1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P < 0.05) than those in that extracted with hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property. CONCLUSION: Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry.

Divergent evolution of multiple virus-resistance genes from a progenitor in Capsicum spp.

Plants have evolved hundreds of nucleotide-binding and leucine-rich domain proteins (NLRs) as potential intracellular immune receptors, but the evolutionary mechanism leading to the ability to recognize specific pathogen effectors is elusive. Here, we cloned Pvr4 (a Potyvirus resistance gene in Capsicum annuum) and Tsw (a Tomato spotted wilt virus resistance gene in Capsicum chinense) via a genome-based approach using independent segregating populations. The genes both encode typical NLRs and are located at the same locus on pepper chromosome 10. Despite the fact that these two genes recognize completely different viral effectors, the genomic structures and coding sequences of the two genes are strikingly similar. Phylogenetic studies revealed that these two immune receptors diverged from a progenitor gene of a common ancestor. Our results suggest that sequence variations caused by gene duplication and neofunctionalization may underlie the evolution of the ability to specifically recognize different effectors. These findings thereby provide insight into the divergent evolution of plant immune receptors.

Effect of the smoking process and firewood type in the phytochemical content and antioxidant capacity of red Jalapeño pepper during its transformation to chipotle pepper.

Chipotle pepper is a dry smoked red Jalapeño pepper well appreciated in the Mexican and American cuisines. Phytochemical content and antioxidant activity of red Jalapeño pepper has been previously reported, however, the effect of the smoking process in the content of phytochemicals, antioxidant capacity and capsaicinoids has not been previously reported. In the present study we found that the smoking process had a significant effect on the content of polyphenolic compounds and antioxidant capacity of red Jalapeño pepper. It induced a nearly 50% increase in total phenols and 15% increase in antioxidant capacity in chipotle pepper compared to fresh samples (in dry weight basis). Capsaicinoids and ascorbic acid content decreased in smoked samples, while carotenoids remained practically unchanged. The strongest effect of smoking was observed in the content of total flavonoids and catechin determined by HPLC. Therefore we can conclude that smoking process has a positive effect in the fruit because it raises its phytochemical properties. The type of wood used in the smoking process also had an effect on the phytochemical content and antioxidant capacity with traditional pecan wood being the best.

Subcellular distribution and chemical forms of cadmium in two hot pepper cultivars differing in cadmium accumulation.

A greenhouse experiment was conducted to compare the subcellular distribution and chemical forms of cadmium (Cd) in roots, stems, leaves, and fruits between a low-Cd cultivar (Yeshengchaotianjiao, YCT) and a high-Cd cultivar (Jinfuzaohuangjiao, JFZ) of hot pepper (Capsicum annuum L.). The Cd concentrations in the root's subcellular fractions, and in all chemical forms in roots, were 1.85-4.88- and 1.84-4.90-fold higher, respectively, in YCT than in JFZ. Compared with JFZ, YCT had significantly lower Cd concentrations in the subcellular fractions (1.10-2.42-fold) of stems and leaves and in almost all chemical forms (1.17-2.97-fold) in the stems and leaves. Also, in fruits, the concentrations of Cd in the cell wall and soluble fractions were 1.18-2.24-fold significantly lower in YCT than in JFZ, and there were lower Cd concentrations (1.36-2.08-fold) in the chemical forms in YCT than in JFZ.