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PubMed2006

Heterologous expression and molecular and cellular characterization of CaPUB1 encoding a hot pepper U-Box E3 ubiquitin ligase homolog.

The U-box motif is a conserved domain found in the diverse isoforms of E3 ubiquitin ligase in eukaryotes. From water-stressed hot pepper (Capsicum annuum L. cv Pukang) plants, we isolated C. annuum putative U-box protein 1 (CaPUB1), which encodes a protein containing a single U-box motif in its N-terminal region. In vitro ubiquitination and site-directed mutagenesis assays revealed that CaPUB1 possessed E3 ubiquitin ligase activity and that the U-box motif was indeed essential for its enzyme activity. RNA gel-blot analysis showed that CaPUB1 mRNA was induced rapidly by a broad spectrum of abiotic stresses, including drought, high salinity, cold temperature, and mechanical wounding, but not in response to ethylene, abscisic acid, or a bacterial pathogen, suggesting its role in the early events in the abiotic-related defense response. Because transgenic work was extremely difficult in hot pepper, in this study we overexpressed CaPUB1 in Arabidopsis (Arabidopsis thaliana) to provide cellular information on the function of this gene in the development and plant responses to abiotic stresses. Transgenic Arabidopsis plants that constitutively expressed the CaPUB1 gene under the control of the cauliflower mosaic virus 35S promoter had markedly longer hypocotyls and roots and grew more rapidly than the wild type, leading to an early bolting phenotype. Microscopic analysis showed that 35S::CaPUB1 roots had increased numbers of small-sized cells, resulting in disordered, highly populated cell layers in the cortex, endodermis, and stele. In addition, CaPUB1-overexpressing plants displayed increased sensitivity to water stress and mild salinity. These results indicate that CaPUB1 is functional in Arabidopsis cells, thereby effectively altering cell and tissue growth and also the response to abiotic stresses. Comparative proteomic analysis showed that the level of RPN6 protein, a non-ATPase subunit of the 26S proteasome complex, was significantly reduced in 35SCaPUB1 seedlings as compared to the wild type. Pull-down and ubiquitination assays demonstrated that RPN6 interacted physically with CaPUB1 and was ubiquitinated in a CaPUB1-dependent manner in vitro. Although the physiological function of CaPUB1 is not yet clear, there are several possibilities for its involvement in a subset of physiological responses to counteract dehydration and high-salinity stresses in transgenic Arabidopsis seedlings.

Amino Acid Motifs↗

PubMed1996

Fruit-specific expression of a defensin-type gene family in bell pepper. Upregulation during ripening and upon wounding.

We have isolated a 454-bp cDNA that encodes a novel fruit specific defensin from bell pepper (Capsicum annuum). The encoded 75-amino-acid polypeptide contains an N-terminal domain characteristic of a signal peptide and a 48-amino-acid mature domain named J1. The mature protein, from which the N-terminal amino acid sequence was determined, contains eight cysteines that from four intramolecular disulfide bridges, suggesting a monomeric form for J1. In healthy fruits J1 is undetectable at the green stage but high levels accumulate during ripening. In wound areas of the green fruit the accumulation of J1 dramatically increased, suggesting a role for J1 in the plant's defense response. Moreover, we have demonstrated that J1 possesses an antifungal activity. We have isolated and characterized the corresponding two homologous genes (j1-1 and j1-2) that exist in the bell pepper genome. Both genes are interrupted by the insertion, at the same position, of one intron of 853 bp for j1-1 and 4900 bp for j1-2. Northern blot and reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism analyses revealed that j1-1 transcripts are present only in fruits, only in trace amounts in mature green fruits, and that they accumulate to high levels in fully ripe fruits, whereas no j1-2 transcripts were detected in the samples monitored.

Amino Acid Sequence↗

PubMed1997

A ubiquitous plant housekeeping gene, PAP, encodes a major protein component of bell pepper chromoplasts.

We have isolated a cDNA (PAP) corresponding to a single nuclear gene that encodes an approximately 30-kD major protein of bell pepper (Capsicum annuum L.) fruit chromoplasts. RNA and protein analyses revealed that, although at a low level, this gene is also expressed in every organ of the plant, the amount of the corresponding transcript and protein dramatically increasing in the latter stages of fruit development. Western-blot and immunocytochemical analyses of purified chloroplasts from leaves and fruits and of chromoplasts from red fruits showed that the encoded protein is the major component of plastoglobules and fibrils and is localized on the outer surface of these lipid structures. Analyses of PAP in plants belonging to different taxa revealed that it is expressed and highly conserved in both monocotyledonous and dicotyledonous plants. The presence of the protein in plastids not differentiating into chromoplasts indicates that PAP is expressed irrespective of the ontogeny of various plastid lines. In light of our results and since the encoded protein, identical to that previously named ChrB or fibrillin, is present in plastoglobules from several species and accumulates in the fibrils of bell pepper chromoplast, we propose to designate it as a plastid-lipid-associated protein.

Amino Acid Sequence↗

PubMed1988

Antitranspirant associated abscisic Acid effects on the water relations and yield of transplanted bell peppers.

Greenhouse and field experiments were performed to determine if increased leaf resistance induced by exogenous application of abscisic acid (ABA) could enhance the water status of transplanted bell pepper seedlings. Seedling survival and yield were also monitored in the field experiment. When seedlings were transplanted into either wet or dry potting mix in the greenhouse, ABA increased leaf resistance and leaf water potential. In the field, plots were irrigated either immediately after, or 1 day after transplanting. Under both treatments, ABA application resulted in increased leaf resistance and water potential, but seedling survival and yield were enhanced due to ABA only in plots which were irrigated 1 day after transplanting. It is concluded that antitranspirant application can reduce transplant shock and increase yield of bell pepper.

Journal Article↗

PubMed2005

Salt-and-Pepper noise removal by median-type noise detectors and detail-preserving regularization.

This paper proposes a two-phase scheme for removing salt-and-pepper impulse noise. In the first phase, an adaptive median filter is used to identify pixels which are likely to be contaminated by noise (noise candidates). In the second phase, the image is restored using a specialized regularization method that applies only to those selected noise candidates. In terms of edge preservation and noise suppression, our restored images show a significant improvement compared to those restored by using just nonlinear filters or regularization methods only. Our scheme can remove salt-and-pepper-noise with a noise level as high as 90%.

Algorithms↗

PubMed2005

The Pun1 gene for pungency in pepper encodes a putative acyltransferase.

Pungency in Capsicum fruits is due to the accumulation of the alkaloid capsaicin and its analogs. The biosynthesis of capsaicin is restricted to the genus Capsicum and results from the acylation of an aromatic moiety, vanillylamine, by a branched-chain fatty acid. Many of the enzymes involved in capsaicin biosynthesis are not well characterized and the regulation of the pathway is not fully understood. Based on the current pathway model, candidate genes were identified in public databases and the literature, and genetically mapped. A published EST co-localized with the Pun1 locus which is required for the presence of capsaicinoids. This gene, AT3, has been isolated and its nucleotide sequence has been determined in an array of genotypes within the genus. AT3 showed significant similarity to acyltransferases in the BAHD superfamily. The recessive allele at this locus contains a deletion spanning the promoter and first exon of the predicted coding region in every non-pungent accession tested. Transcript and protein expression of AT3 was tissue-specific and developmentally regulated. Virus-induced gene silencing of AT3 resulted in a decrease in the accumulation of capsaicinoids, a phenotype consistent with pun1. In conclusion, gene mapping, allele sequence data, expression profile and silencing analysis collectively indicate that the Pun1 locus in pepper encodes a putative acyltransferase, and the pun1 allele, used in pepper breeding for nearly 50 000 years, results from a large deletion at this locus.

Acyltransferases↗

PubMed2005

Molecular mapping of the chlorophyll retainer (cl) mutation in pepper (Capsicum spp.) and screening for candidate genes using tomato ESTs homologous to structural genes of the chlorophyll catabolism pathway.

The chlorophyll retainer (cl) mutation causes inhibition of chlorophyll degradation during pepper fruit ripening and is controlled by a single recessive gene. The retention of chlorophyll in mature red or yellow fruits produces brown- or green-colored ripe fruits, respectively. We mapped CL on chromosome 1 of pepper corresponding to chromosome 8 in tomato in which a homologous mutation, green flesh, was previously assigned. To test whether known structural genes from the chlorophyll catabolism pathway could correspond to CL, we mapped tomato expressed sequence tag clones corresponding to three loci of CHLOROPHYLLASE and one locus of PHEOPHORBIDE A OXYGENASE in the tomato introgression lines population. The three CHLOROPHYLLASE loci mapped to chromosomes 6, 9, and 12, while PHEOPHORBIDE A OXYGENASE mapped to chromosome 11, indicating that CL may correspond to an as yet unavailable gene from the chlorophyll catabolism pathway or to a regulator of the pathway.

Capsicum↗

PubMed1995

A survey of DNA polymorphism within the genus Capsicum and the fingerprinting of pepper cultivars.

Interspecific genetic variation was examined in the genus Capsicum based on shared restriction fragments in Southern analyses. Four distinct clusters were delineated among 21 accessions of cultivated and wild pepper (C. annuum, C. baccatum, C. chacoense, C. chinense, and C. frutescens). Three tight clusters comprised of accessions belonging to C. annuum, C. frutescens, and C. baccatum, respectively, were formed, along with a fourth cluster comprised of one accession each of C. chinense and C. chacoense. All accessions were differentiated by this technique, and the clusters corresponded closely to previous morphology-based classification. Sufficient DNA polymorphism exists among these accessions that segregating populations useful for restriction fragment length polymorphism (RFLP) mapping could be constructed using any two pepper accessions as parents. Regression analysis indicates that genetic distance is a good predictor (R2 = 0.872) of the level of mappable DNA polymorphism in Capsicum. Intraspecific variability was examined among four C. annuum cultivars (NuMex R Naky, Jupiter, Perennial, and Criollo de Morelos 334) using both RFLPs and randomly amplified polymorphic DNA (RAPDs), allowing a comparative evaluation of the two techniques. Seventeen percent of the clones used singly in RFLP analyses were sufficient for the differentiation of these varieties, as were 12.5% of the RAPD PCR amplifications. Dendrograms constructed from RFLP and RAPD analyses of the intraspecific data are similar but not identical. Southern analysis and RAPD PCR should be useful for DNA fingerprinting and the discrimination of closely related C. annuum genotypes.

Agriculture↗

PubMed1998

Diversity among xanthomonads pathogenic on pepper and tomato.

Xanthomonas campestris pv. vesicatoria, causal agent of bacterial spot of tomato and pepper, had been considered for nearly 70 years to be a relatively homogeneous organism. However, in the past decade this bacterium was determined to be composed of two genetically and phenotypically distinct groups. The two groups, designated A and B, were distinguished based on amylolytic activity, expression of unique protein bands, reaction on differential hosts (tomato races T1 and T2), reaction patterns with monoclonal antibodies, DNA restriction profiles, and DNA:DNA hybridization. The A and B groups were placed into X. axonopodis pv. vesicatoria and X. vesicatoria, respectively. A third group, designated C, was pathogenically (race T3) and serologically distinct from A and B strains, and formed unique DNA restriction profiles. DNA:DNA hybridization data suggest that C is distinct but related to A strains and may represent a subspecies of A. A final group, designated D, consisted of X. gardneri, an organism identified in Yugoslavia in 1957, and also found in Costa Rica. Group D was determined to be genetically distinct from strains within the other two groups; it represents a third Xanthomonas species pathogenic on tomato and pepper.

Journal Article↗

PubMed2006

Effects of CH-19 sweet, a non-pungent cultivar of red pepper, in decreasing the body weight and suppressing body fat accumulation by sympathetic nerve activation in humans.

'CH-19 Sweet' is a non-pungent red pepper and enhances the energy expenditure in humans in like manner to the pungent red pepper. We investigated in this study the effects of a repeated intake of CH-19 Sweet for two weeks on the body weight and body fat in humans. Changes in the autonomic nervous activity after ingesting CH-19 Sweet were also measured by a power spectral analysis. We established a new protocol which allows the precise detection of weight change in humans by using fewer subjects. These methods were used to show that the repeated intake of CH-19 Sweet reduced the body weight and suppressed body fat accumulation. Furthermore, the body weight loss due to the repeated intake of CH-19 Sweet was significantly correlated with the sympathetic nervous response after its ingestion. We propose that the repeated intake of CH-19 Sweet reduced the body weight and suppressed body fat accumulation by sympathetic nervous activation in humans.

Adipose Tissue↗

PubMed1998

Molecular cloning and sequence analysis of catalase cDNA from green pepper seedlings elicited with arachidonic acid.

We isolated a cDNA encoding catalase from green pepper seedlings elicited with arachidonic acid, based on the amino acid sequences of the purified protein. The nucleotide sequence of the isolated cDNA contained a single open reading frame predicted to encode 492 amino acid residues with a calculated molecular mass of 56439.0 daltons. The deduced amino acid sequence contained the amino acid sequences found by sequencing of the peptides. The total deduced amino acid sequence showed high similarity with those of the other plant catalases reported so far and was found to possess the peroxisomal targeting sequence conserved among plant catalases. Transcription of the catalase gene in green pepper seedlings was found to be induced by treatment with arachidonic acid.

Amino Acid Sequence↗

PubMed2005

Ovipositional deterrent in the sweet pepper, Capsicum annuum, at the mature stage against Liriomyza trifolii (Burgess).

Liriomyza trifolii (Burgess), the American serpentine leafminer fly, is well known as a serious pest throughout the world. This insect attack over 21 different plant families including solanaceae plants. The mature sweet pepper, Capsicum annuum (Solanaceae), however, shows resistance to this leafminer fly. This resistance is based on the ovipositional deterrent in the sweet pepper leaf against the fly species. Based on bioassay-guided fractionation, luteolin 7-O-beta-D-apiofuranosyl-(1-->2)-beta-D-glucopyranoside was isolated and identified as the ovipositional deterrent against this insect species. This compound completely deterred L. trifolii females from laying their eggs on a host plant leaf treated at 4.90 microg/cm2.

Animals↗

PubMed1991

Cough in hot pepper workers.

STUDY OBJECTIVE: To determine whether there is an effect on the prevalence of respiratory symptoms, an alteration in lung function, or an increase in the cough threshold to capsaicin among workers chronically exposed to hot chili (Capsicum) peppers. DESIGN: Cross-sectional study of responses to a structured questionnaire, lung function assessed by spirometry and cough threshold to inhalation of capsaicin aerosol in a group of occupationally-exposed Capsicum workers as compared to non-exposed employees of the same work site. SETTING: Spice manufacturing facility. PARTICIPANTS: Twenty-two Capsicum-exposed and 19 nonexposed workers. MEASUREMENTS AND MAIN RESULTS: When evaluated by questionnaire, 13 (59 percent) of the Capsicum-exposed workers reported cough as compared to 4 (21 percent) of the nonexposed workers (p less than 0.05). Baseline FEV1 and FVC did not differ between the two groups. Cough threshold, as assessed by the lowest concentration of inhaled capsaicin eliciting cough, was related to workplace exposure (p = 0.05), displaying a bimodal pattern of higher and lower cough thresholds among the Capsicum workers as compared to a unimodal distribution among the nonexposed workers. Within the exposed group, a higher cough threshold was significantly related to male gender (p = 0.03) and was associated to a lesser extent with dietary preference for hot food (p = 0.09) and cumulative cigarette smoking (p = 0.07). CONCLUSION: Chronic occupational exposure to chili peppers is associated with complaints of cough but does not alone lead to decreased responsiveness of capsaicin-sensitive nerves when assessed by cough threshold. The cough response to capsaicin inhalation may be modified by the effects of multiple, potentially interactive factors.

Adult↗

PubMedDate not supplied

Ovipositional deterrent on mature stage of sweet pepper, Capsicum annuum, against Liriomyza trifolii (Burgess).

Liriomyza trifolii (Burgess), the American serpentine leafminer fly, is a well-known serious pest in the world. This insect species attacks plants of more than 21 families including Solanaceae plants. A sweet pepper, Capsicum annuum (Solanaceae), on mature stage, however, shows resistance to this leafminer fly. This resistance is based on the ovipositional deterrent in the sweet pepper leaf against the fly species. Based on the bioassay guided fractionation, phytol [(2E)-3,7,11,15-tetramethyl-2-hexadecen-1-ol] was isolated and identified as an ovipositional deterrent against this insect species. The yield of this compound was 815 microg/g fresh leaf of C. annuum. This compound completely deterred the females from laying their eggs on host plant leaves treated at 35.2 microg/cm2.

Animals↗

PubMed2003

Integrated management tactics for Frankliniella thrips (Thysanoptera: Thripidae) in field-grown pepper.

In a 2-yr study, the impacts of different plastic soil mulches, insecticides, and predator releases on Frankliniella thrips and their natural enemies were investigated in field-grown peppers. Ultraviolet light (UV)-reflective mulch significantly reduced early season abundance of adult thrips compared with standard black plastic mulch. This difference diminished as the growing seasons progressed. Late season abundance of thrips larvae was higher in UV reflective mulch compared with black mulch plots. The abundance of the predator Orius insidiosus (Say) was significantly lower in UV-reflective mulch compared with black mulch treatments. Infection of plants with tomato spotted wilt virus, a pathogen vectored by Frankliniella occidentalis (Pergande), was <6%. In the year with the higher disease incidence (2000), UV-reflective mulch plots had significantly less disease (1.9%) compared with black mulch plots (4.4%). Yield was significantly higher in UV-reflective mulch (24,529 kg/ha) compared with black mulch (15,315 kg/ha) during this year. Effects of insecticides varied with species of thrips. Spinosad reduced abundance of F. occidentalis, but not Frankliniella tritici. In contrast, esfenvalerate and acephate reduced numbers of F. tritici and Frankliniella bispinosa, but resulted in higher populations of F. occidentalis. Spinosad was the least disruptive insecticide to populations of O. insidiosus. Releases of O. insidiosus and Geocoris punctipes (Say) reduced populations of thrips immediately after releases; naturally occurring predators probably provided late season control of thrips. Our results suggest that UV-reflective mulch, combined with early season applications of spinosad, can effectively reduce abundance of thrips in field-grown pepper.

Agriculture↗

PubMed1987

Capsicum and capsaicin--a review: case report of the use of hot peppers in child abuse.

Capsaicin, the active principle of hot peppers of the genus Capsicum, exhibits broad bioactivity. It targets neuronal structures which contain substance P, clinically seen as gastrointestinal and dermatologic irritation, bronchospasm and fibrinolysis. As a research tool, capsaicin profoundly alters neurologic anatomy and function. We review the toxicity of capsaicin and comment briefly on the use of hot peppers in child abuse.

Animals↗

PubMed2006

Larvicidal effect of pepper plants on Aedes aegypti (L.) (Diptera: Culicidae).

Ethanolic extracts derived from three species of the Piperaceae (pepper) family, Piper longum L., P. ribesoides Wall., and P. sarmentosum Roxb. ex Hunt., were evaluated for efficacy against early 4th instar larvae of Aedes aegypti mosquitoes using larvicidal bioassays. The highest larvicidal efficacy was established from P. longum, followed by P. sarmentosum and P. ribesoides, with LC50 values of 2.23, 4.06, and 8.13 ppm, respectively. Observations of morphological alterations on treated 4th instar larvae revealed that most organs, except anal papillae, had a normal structural appearance that was similar to controls. Under light microscopy, the internal structures of anal papillae in the treated larvae showed shrinkage, while the external features were normal in appearance. Ultrastructural studies, however, clearly demonstrated external destruction, with extensive damage and shrunken cuticle of the anal papillae. The structural deformation of anal papillae probably led to their dysfunction, which may be intrinsically associated with the death of the larvae. This study affords some evidence regarding the action site of the pepper extracts and suggests their potential in developing new types of larvicides used for mosquito control.

Aedes↗

PubMed2001

Response surface modeling for the inactivation of Escherichia coli O157:H7 on green peppers (Capsicum annuum L.) by chlorine dioxide gas treatments.

The effects of chlorine dioxide (ClO2) gas concentration (0.1 to 0.5 mg/liter), relative humidity (RH) (55 to 95%), treatment time (7 to 135 min), and temperature (5 to 25 degrees C) on inactivation of Escherichia coli O157:H7 on green peppers were studied using response surface methods. A four-factor, central, composite, rotatable design was used. The microbial log reduction was measured as a response. A direct membrane-surface-plating method with tryptic soy agar and sorbitol MacConkey agar was used to resuscitate and enumerate ClO2-treated E. coli O157:H7 cells. The statistical analysis and the predictive model developed in this study suggest that ClO2 gas concentration, treatment time, RH, and temperature all significantly (P < 0.01) increased the inactivation of E. coli O157:H7. ClO2 gas concentration was the most important factor, whereas temperature was the least significant. The interaction between ClO2 gas concentration and RH indicated a synergistic effect. The predictive model was validated, and it could be used to determine effective ClO2 gas treatments to achieve a 5-log reduction of E. coli O157:H7 on green peppers.

Capsicum↗