Search

Key message: A plant growth regulator, 5-aminolevulinic acid, enhanced the saline-alkali tolerance via photosynthetic, oxidative-reduction, and glutathione metabolism pathways in pepper seedlings. Saline-alkali stress is a prominent environmental problem, hindering growth and development of pepper. 5-Aminolevulinic acid (ALA) application effectively improves plant growth status under various abiotic stresses. Here, we evaluated morphological, physiological, and transcriptomic differences in saline-alkali-stressed pepper seedlings after ALA application to explore the impact of ALA on saline-alkali stress. The results indicated that saline-alkali stress inhibited plant growth, decreased biomass and photosynthesis, altered the osmolyte content and antioxidant system, and increased reactive oxygen species (ROS) accumulation and proline content in pepper seedlings. Conversely, the application of exogenous ALA alleviated this damage by increasing the photosynthetic rate, osmolyte content, antioxidant enzyme activity, and antioxidants, including superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, and reducing glutathione to reduce ROS accumulation and malonaldehyde content. Moreover, the transcriptomic analysis revealed the differentially expressed genes were mainly associated with photosynthesis, oxidation–reduction process, and glutathione metabolism in saline-alkali stress + ALA treatment compared to saline-alkali treatment. Among them, the change in expression level in CaGST, CaGR, and CaGPX was close to the variation of corresponding enzyme activity. Collectively, our findings revealed the alleviating effect of ALA on saline-alkali stress in pepper seedlings, broadening the application of ALA and providing a feasible strategy for utilize saline-alkali soil. [ABSTRACT FROM AUTHOR]

Meloidogyne hispanica infects many economically important crops worldwide and has been listed as a quarantine pest in many countries and as an invasive alien species in China. Accurate identification of this pathogen is essential for the establishment of efficient and sustainable integrated pest management programs. During the field investigations in Hainan, China, we discovered galled roots caused by nematode infestation in the pepper field. Further identification of the nematode isolated from the root galls, including morphological and molecular techniques, confirmed that the isolated population infesting the pepper roots belonged to the species M. hispanica. Upon artificial inoculation under greenhouse conditions, the isolated nematodes induced symptoms that closely resembled those observed in the field. To the best of our knowledge, this is the first documented case of M. hispanica parasitizing pepper crops in China, which will provide valuable basis to formulate targeted control strategies. [ABSTRACT FROM AUTHOR]

Plants in various republics of the world face many dangers, including diseases that threaten crop productivity. The development and increase of novel species of infectious pathogens have made plant growth threatened. Fusarium wilt is one of the fiercest diseases affecting vegetables, which causes a great loss in the quality and quantity of pepper plants all over the world. In this study, stimulation of physiological immune responses in pepper plant using ecofriendly inducers (Aspergillus alabamensis, Aspergillus oryzae, and Aspergillus tubingensis) against Fusarium wilt had been studied. Endophytic fungi were assayed for their capability to synthesize hydrocyanic acid, phosphate solubilization, siderophores, and indole acetic acid synthesis, and the antifungal potential of ecofriendly inducers against F. oxysporum was also examined. A notable antifungal potential antifusarial with a supreme activity of A. tubingensis was found. More ultrastructure by TEM of Fusarium showed that sharp changes occurred in the cell wall, mycelium, and conidia as a result of treatment with A. tubingensis, A. oryzae, and A. alabamensis. The results demonstrated the high severity of F. oxysporum on pepper seedlings. Infected seedlings showed a high reduction in all vegetative parameters, photosynthesis, entire protein, and total carbohydrate. In the current study, the potential of endophytic fungi through foliar and soil application was applied to the Fusarium-infected pepper plants under pot conditions. Disease index, vegetative growth, photosynthetic pigments, osmolyte content, stress markers, and antioxidant isozymes were assessed. The achieved result indicates that tested endophytes through two modes (foliar and soil) lowered PDI and produced high protection, with the most protection influence represented by A. tubingensis (through the soil) by 83.33%. It was concluded that use of A. tubingensis, A. alabamensis, and A. oryzae could be commercially used as eco-friendly agents for the defense of pepper seedlings against Fusarium wilt disease. [ABSTRACT FROM AUTHOR]

Pollination plays a vital role in maintaining ecological functioning of ecosystems, and bees are the main pollinating insects in natural and agricultural areas. Identification of bee food sources can be carried out directly by observing their visits to flowers, or indirectly by analyzing the pollen they carry. Pollen analysis is employed to determine the breadth of the bees' dietary niche and understand the relationship between flower traits, pollen grains, and floral resources. While Exomalopsis females were previously recorded as pollinators of Solanaceae species, information regarding their trophic niche in agricultural areas remains limited but is essential for the management of these wild pollinators. In this study we accessed the floral resources used by two Exomalopsis species (E. analis and E. auropilosa) through pollen analysis in their scopae, using cultivated Capsicum cultivars (Solanaceae) as target plants. Pollen samples from 56 Exomalopsis females (21 from E. analis and 35 from E. auropilosa) revealed 58 pollen types belonging to 24 botanical families, with the highest values found for Fabaceae, Asteraceae, Euphorbiaceae, and Rubiaceae. E. auropilosa showed greater pollen type richness (46) with 3–10 types per bee, while E. analis had 43 types with 3–13 types per individual. Capsicum, a pollen, and nectar source constituted approximately 77% of the pollen loads. Most of other plant species identified were arboreal and provided nectar to these pollinators. Trophic niche overlap between Exomalopsis species was low. The conservation of wildflowers surrounding pepper cultivations is essential for maintaining these two important pollinators in agricultural areas. Additionally, areas with bare soil can contribute to the persistence of Exomalopsis populations. [ABSTRACT FROM AUTHOR]

Potato spindle tuber viroid (PSTVd; genus Pospiviroid) was detected from pepper (Capsicum annuum) seeds produced in Vietnam during an export inspection. The PSTVd isolate (PSTVd-VN) maintained its viability. The phylogenetic relationship between PSTVd-VN and other PSTVd variants that were isolated from other plants and was classified into lethal and severe strains. PSTVd-VN in tomatoes (cv. Rutgers) caused severe stunting and necrosis of the stems and leaf veins, but no symptoms in inoculated pepper plants except that the fruits were smaller than the control peppers. To our knowledge, this is the first report of PSTVd from pepper seeds produced in Vietnam. [ABSTRACT FROM AUTHOR]

Tomato spotted wilt virus (TSWV) is considered one of the most threatening viruses worldwide for different economically important agricultural crops. In this scenario, it is important to perform an early detection by laboratory tests to prevent TSWV spread. A rapid and sensitive TSWV detection protocol based on real time reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed in this work, also using cost-effective and simplified sample preparation procedure, to assess the suitability of the RT-LAMP assay in field conditions on tomato and pepper samples. A set of six primers was designed within the nucleotide sequence region coding for the nucleocapsid protein (N) of segment S, targeting a 220-nucleotide sequence. Sensitivity, specificity, accuracy, and in-field application of the real-time RT-LAMP assay were evaluated. The developed real-time RT-LAMP assay proved to be one thousand and one hundred times more sensitive than end-point RT-PCR and real-time RT-PCR methods, respectively, detecting a total of 9.191 × 101 genome copies as minimum target, and no cross-reactivity were detected with other viruses belonging to Tospoviridae and Bromoviridae families used as outgroup. In addition, the in-field application of the assay using the rapid sample preparation gave adequate and reliable results within 60 minutes, with an acceptable reaction delay when compared to canonical RNA extraction. The in-field analyses showed an increase of TSWV-positive samples (37%) detection compared with end-point RT-PCR and real-time RT-PCR (32% and 29%, respectively), particularly on asymptomatic samples, confirming that the real-time RT-LAMP assay can be implemented as a routine test both in-field and laboratory conditions as a rapid and sensitive technique for TSWV detection. [ABSTRACT FROM AUTHOR]

Key message: Exogenous SL positively regulates pepper DS by altering the root morphology, photosynthetic character, antioxidant enzyme activity, stomatal behavior, and SL-related gene expression. Drought stress (DS) has always been a problem for the growth and development of crops, causing significant negative impacts on crop productivity. Strigolactone (SL) is a newly discovered class of plant hormones that are involved in plants’ growth and development and environmental stresses. However, the role of SL in response to DS in pepper remains unknown. DS considerably hindered photosynthetic pigments content, damaged root architecture system, and altered antioxidant machinery. In contrast, SL application significantly restored pigment concentration modified root architecture system, and increased relative chlorophyll content (SPAD). Additionally, SL treatment reduced oxidative damage by reducing hydrogen peroxide (H2O2) (24–57%) and malondialdehyde (MDA) (79–89%) accumulation in pepper seedlings. SL-pretreated pepper seedlings showed significant improvement in antioxidant enzyme activity, proline accumulation, and soluble sugar content. Furthermore, SL-related genes (CcSMAX2, CcSMXL6, and CcSMXL3) were down-regulated under DS. These findings suggest that the foliar application of SL can alleviate the adverse effects of drought tolerance by up-regulating chlorophyll content and activating antioxidant defense mechanisms. [ABSTRACT FROM AUTHOR]

Key message: Pepper fruits contain two leucine aminopeptidase (LAP) genes which are differentially modulated during ripening and by nitric oxide. The LAP activity increases during ripening but is negatively modulated by nitration. Leucine aminopeptidase (LAP) is an essential metalloenzyme that cleaves N-terminal leucine residues from proteins but also metabolizes dipeptides and tripeptides. LAPs play a fundamental role in cell protein turnover and participate in physiological processes such as defense mechanisms against biotic and abiotic stresses, but little is known about their involvement in fruit physiology. This study aims to identify and characterize genes encoding LAP and evaluate their role during the ripening of pepper (Capsicum annuum L.) fruits and under a nitric oxide (NO)-enriched environment. Using a data-mining approach of the pepper plant genome and fruit transcriptome (RNA-seq), two LAP genes, designated CaLAP1 and CaLAP2, were identified. The time course expression analysis of these genes during different fruit ripening stages showed that whereas CaLAP1 decreased, CaLAP2 was upregulated. However, under an exogenous NO treatment of fruits, both genes were downregulated. On the contrary, it was shown that during fruit ripening LAP activity increased by 81%. An in vitro assay of the LAP activity in the presence of different modulating compounds including peroxynitrite (ONOO−), NO donors (S-nitrosoglutathione and nitrosocyteine), reducing agents such as reduced glutathione (GSH), l-cysteine (l-Cys), and cyanide triggered a differential response. Thus, peroxynitrite and reducing compounds provoked around 50% inhibition of the LAP activity in green immature fruits, whereas cyanide upregulated it 1.5 folds. To our knowledge, this is the first characterization of LAP in pepper fruits as well as of its regulation by diverse modulating compounds. Based on the capacity of LAP to metabolize dipeptides and tripeptides, it could be hypothesized that the LAP might be involved in the GSH recycling during the ripening process. [ABSTRACT FROM AUTHOR]

Pepper (Capsicum annuum L.) is one of the most widely cultivated species and is highly valued for its pungency. The pungency of pepper is primarily attributed to a group of chemical compounds known as capsaicinoids. These compounds are synthesized in the placental tissue of pepper fruits through the activation of specific genes and enzymes, thereby contributing to their pungency. Protoplast-based gene expression systems have been considered an efficient method for gene function studies, protein-protein interactions, promoter analysis, and subcellular localization. Here, we optimized an efficient protocol for isolating protoplasts from pepper placental tissues and the polyethylene glycol (PEG)-mediated transient expression of green fluorescent proteins (GFP). Several factors affecting GFP expression in intact protoplasts were evaluated and optimized in this study. Protoplast isolation was carried out using 2.0% cellulase "onozuka" R-10 and 0.3% macerozyme R-10 solution. Different amounts of plasmid DNA and various incubation times for transfection with 40% PEG resulted in different transfection efficiencies (78–85%). The highest GFP transformation efficiency was observed when 120 µL protoplast suspension (3 × 107 to 5 × 107/mL) was mixed with 15 µg plasmid DNA and incubated for 25 min with an equal volume of 40% PEG. The improved protocol described in this study can be helpful for the isolation and transfection of pepper placenta-originated protoplasts and for the rapid investigation of pepper gene functions. [ABSTRACT FROM AUTHOR]

Xanthomonas euvesicatoria is a major cause of bacterial spot disease in various crops. The present study was focused on the pathosystem pepper (Capsicum annuum L.) - X. euvesicatoria 269p (wild strain). The infectious process was studied using several different modes of in vivo inoculation under controlled conditions. The spread of the pathogen in different parts of the plants was monitored by a new qPCR procedure developed for the detection of X. euvesicatoria, as well as by re-isolation of viable bacterial cells. Photosynthesis, the number of viable pathogens, oxidative stress markers, activities of the main antioxidant enzymes, and levels of non-enzymatic antioxidants in the novel single-leaf model system were studied. The most important observation is that the invasion of the pathogen causes local infection and the dissemination of bacteria to the healthy parts of the host is blocked. The plants limit bacterial colonization around the entry points. Oxidative burst and alterations in antioxidant defenses are detected in infectious leaf lesions. Localized ROS overproduction resembles a hypersensitive response, but several differences can be observed. We assumed that pepper plants are more likely to manifest an intermediate phenotype, similar to lesions simulating disease or leaf flecking. By localizing the infection, possibly involving oxidative stress, the plant survives. However, the same applies to bacteria. The pathogen multiplies at the infection spots and is transmitted to other plants. Our conclusion is that the intermediate phenotype in the studied pathosystem is an example of long and successful co-evolution for both species. [ABSTRACT FROM AUTHOR]

The human–robot interaction (HRI) field goes beyond the mere technical aspects of developing robots, often investigating how humans perceive robots. Human perceptions and behavior are determined, in part, by expectations. Given the impact of expectations on behavior, it is important to understand what expectations individuals bring into HRI settings and how those expectations may affect their interactions with the robot over time. For many people, social robots are not a common part of their experiences, thus any expectations they have of social robots are likely shaped by other sources. As a result, individual expectations coming into HRI settings may be highly variable. Although there has been some recent interest in expectations within the field, there is an overall lack of empirical investigation into its impacts on HRI, especially in-person robot interactions. To this end, a within-subject in-person study ( N = 31 ) was performed where participants were instructed to engage in open conversation with the social robot Pepper during two 2.5 min sessions. The robot was equipped with a custom dialogue system based on the GPT-3 large language model, allowing autonomous responses to verbal input. Participants' affective changes towards the robot were assessed using three questionnaires, NARS, RAS, commonly used in HRI studies, and Closeness, based on the IOS scale. In addition to the three standard questionnaires, a custom question was administered to capture participants' views on robot capabilities. All measures were collected three times, before the interaction with the robot, after the first interaction with the robot, and after the second interaction with the robot. Results revealed that participants to large degrees stayed with the expectations they had coming into the study, and in contrast to our hypothesis, none of the measured scales moved towards a common mean. Moreover, previous experience with robots was revealed to be a major factor of how participants experienced the robot in the study. These results could be interpreted as implying that expectations of robots are to large degrees decided before interactions with the robot, and that these expectations do not necessarily change as a result of the interaction. Results reveal a strong connection to how expectations are studied in social psychology and human-human interaction, underpinning its relevance for HRI research. [ABSTRACT FROM AUTHOR]

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

Global food security is constantly threatened by emerging plant viruses, which cause outbreaks that reduce the yield and the quality of crops that sustain food chains. Tomato brown rugose fruit virus (ToBRFV) (genus Tobamovirus, family Virgaviridae) is an emerging plant virus which, since first being reported in Jordan in 2015, has spread to many countries in the Americas, Asia, Africa, and Europe causing high losses in tomato and pepper crops. We have carried out a survey of ToBRFV in Iran and performed the biological and molecular characterization of a pepper ToBRFV isolate from Yazd province. Our results show that ToBRFV was distributed in nine provinces of Iran during 2021–22. ToBRFV–Yazd induces mild-to-severe mosaic symptoms on tomato, deformation and stunting in infected pepper, necrotic lesions on pepper fruit, systemic symptoms on Datura metel, necrotic local lesions on Gompherena globosa, and chlorotic local lesions on Chenopodium amaranticolor. No symptoms were observed on cucumber, melon, and cowpea. The complete genome sequence of ToBRFV–Yazd was determined, the first complete genome sequence for a ToBRFV isolate from Iran. The sequence is 6,392 nucleotides long and includes four open reading frames encoding the typical tobamovirus proteins. Sequence comparisons and phylogenetic analysis with ToBRFV isolates from different countries indicated a very high degree of genetic uniformity among ToBRFV isolates, suggesting a short evolutionary history. [ABSTRACT FROM AUTHOR]

Fusarium wilt disease of pepper caused by Fusarium oxysporum is a devastating disease causing severe crop losses. The present study investigated the efficacy of benzothiadiazole (Bion®) and of indigenous rhizobacteria as potential biocontrol agents to manage this disease. Pathogenicity tests results demonstrated that isolate "F3", identified as Fusarium oxysporum, caused higher disease severity (85%) than other isolates. Out of eight bacterial strains, isolate "RB4," identified as Bacillus subtilis, showed a strong antifungal potential by causing higher (60%) mycelial growth reduction of F. oxysporum. The combined in vitro seed treatment with Bion® and B. subtilis increased the germination rate (84%) of pepper seeds. The germination rate caused by the combined treatment was relatively higher than the rates obtained when Bion® (65%) and B. subtilis (79%) were applied individually and significantly higher than those of the infected control (50%). In greenhouse experiments, we also documented a promising reduction in disease severity (64.7% and 70.6%) in plants treated with Bion® and B. subtilis. Moreover, the application of the conventional fungicide "captan" also showed considerable reduction in disease severity (88.2%). These results indicate that the combined application of Bion® and B. subtilis significantly increased their capability to combat fungal pathogens by reducing disease severity. Additionally, the application of B. subtilis and Bion® increased (0.12 and 0.19 g/kg Fw, respectively) the total phenol contents in treated plants, compared to plants treated only with the fungicide and to infected control (0.06 g/kg Fw) plants. The results of the present study suggested that the use of naturally occurring bacterial microbes as putative biocontrol in combination with Bion® may be considered a promising method for the control of Fusarium wilt disease of pepper, and the combined application of these treatments probably induces pathogen resistance in plants. [ABSTRACT FROM AUTHOR]

Polyamines have been reported to have cell proliferative and anti-inflammatory effects on normal metabolism in the body. This study aimed to investigate polyamine content of AIG01 pepper and the anti-inflammatory effect of AIG01 pepper extract (PAE) in mice. Polyamine content was analyzed by HPLC after acid hydrolysis of peppers with different acidic solvents. AIG01 pepper has the highest total polyamine content at about 1.5 mg/g. In LPS-stimulated RAW264.7, PAE inhibits nitric oxide production in a concentration-dependent manner and decreased the levels of pro-inflammatory cytokines. PAE has been shown to inhibit phosphorylation of MAPK/ERK. In TPA-stimulated Balb/C, PAE treatment showed tissue-level reductions in pro-inflammatory cytokines, reductions in ear thickness, and inhibition of neutrophil invasion. The polyamine content, polyamine extraction efficiency and anti-inflammatory effect of AIG01 obtained in this study suggest that it is useful as a raw material for the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

A total of one-hundred and fourteen Capsicum annum L. samples were collected from Qassim and Al-Baha regions, Saudi Arabia in the growing season of 2021–2022, showing virus like symptoms including, mottling, mosaic, chlorosis, leaf distortion, stunted growth, and necrotic lesions, dwarfing of leaves and fruits. These samples were tested against important viruses infecting pepper using ELISA kits. According to ELISA results, 80/114 (70%) samples were found to be infected with one or more of the tested viruses. However, incidence of the PMMoV was observed in 18/21 (85.7%) and 23/59 (38.98%) from Al-Baha and Qassim regions respectively. Based on highly positive ELISA samples of PMMoV three samples were selected for biological detection using mechanical inoculation with sap prepared and the results showed that systemic mosaic, mottling, necrotic spots, yellowing on N. tabacum, N. benthamiana, N. glutinosa, Solanum nigrum and necrotic and chlorotic spots on Chenopodium quinoa and C. amranticolor, while local lesions symptoms were produced on Datura stramonium. According to the ELISA results, positive samples from Qassim and Al-Baha regions were amplified by RT-PCR analysis, and 474-bp fragment was amplified using PMMoV specific primers. Two directional sequencing was done for the amplified products and the sequences of the virus isolates were submitted in the NCBI database with the following accession numbers, OP723368, OP723369, OP723370, OP723371, OP723372. The phylogenetic analysis showed the close relationship our isolates with other isolation of PMMoV and pairwise nucleotide sequence identity analysis revealed that these PMMoV isolates shared their identity between 92.5 and 100% with PMMoV isolates available in the databases. This study provides comprehensive report regarding the diagnosis of chili infecting viruses through serological and characterization of PMMoV through serological, biological, and molecular methods in the kingdom of Saudi Arabia. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Carboxylesterases (CXEs) catalyze the hydrolysis of carboxylic acid esters into the corresponding acids and alcohols. Previously, a carboxylesterase gene was isolated from pepper (Capsicum annuum L.) and designated as PepEST. This gene is highly expressed during the incompatible interaction between ripe fruits of pepper and an anthracnose fungus (Colletotrichum gloeosporioides), and the PepEST protein exhibits an antifungal activity by suppressing fungal growth with the inhibition of appressorium formation. In this study, a PepEST-homologous gene was newly isolated from the pepper genome, which is designated as PepEST2 (the original PepEST gene is re-named here as PepEST1). Compared with PepEST1 whose expression is only induced by inoculation of the fungus, PepEST2 is not induced by fungus infection, rather expressed mainly in roots. Subcellular localization analysis using tobacco protoplasts showed that both PepEST1 and PepEST2 proteins are localized in the cytoplasm, and enzymatic activity assays showed similar Vmax and Km values of PepEST2 to those of PepEST1. Antifungal activity assays against C. gloeosporioides demonstrated that not only PepEST1 but also PepEST2 was able to suppress the fungal growth by inhibiting the appressorium formation. In addition, the antifungal activity of PepEST2 was higher than that of PepEST1. Collectively, this study suggests that two closely related members of pepper CXEs are functionally diversified due to the differential expression patterns, and also provides PepEST2 as an alternative gene to confer disease resistance to plants. [ABSTRACT FROM AUTHOR]

Background: Pepper (Capsicum annum L.) is the main crop in the vegetable industry. The growth and development of peppers are regulated by nitrate, but there is limited research on the molecular mechanisms of nitrate absorption and assimilation in peppers. A plant specific transcription factor NLP plays an important role in nitrate signal transduction. Methods and results: In this study, a total of 7 NLP members were identified based on pepper genome data. Two nitrogen transport elements (GCN4) were found in the CaNLP5 promoter. In the phylogenetic tree, CaNLP members are divided into three branches, with pepper NLP and tomato NLP having the closest genetic relationship. The expression levels of CaNLP1, CaNLP3, and CaNLP4 are relatively high in the roots, stems, and leaves. The expression level of CaNLP7 gene is relatively high during the 5–7 days of pepper fruit color transformation. After various non-Biotic stress and hormone treatments, the expression of CaNLP1 was at a high level. The expression of CaNLP3 and CaNLP4 was down regulated in leaves, but up regulated in roots. Under conditions of nitrogen deficiency and sufficient nitrate, the expression patterns of NLP genes in pepper leaves and roots were determined. Conclusion: These results provide important insights into the multiple functions of CaNLPs in regulating nitrate absorption and transport. [ABSTRACT FROM AUTHOR]

In a greenhouse complex located in the northwest of Iran, yellow-colored spots and deformation were observed on the fruit of bell pepper plants. Analysis of ten collected fruits showed the presence of both tomato brown rugose fruit virus (ToBRFV) and tomato spotted wilt virus (TSWV) viruses, indicating mixed-infection in three of the ten sampled pepper fruits. The S segment of TSWV was amplified using specific primers for the nonstructural protein (NSs), intergenic regions (IGR), and nucleocapsid protein (NP) gene. Sequence comparison of the coat protein (CP) gene of the ToBRFV isolate revealed that the new ToBRFV isolate formed a sister group with the previously reported Iran-1 isolate from Iran. Phylogenetic analysis of the S segment and its two ORFs (NSs and N) resulted in three groups. The analysis based on NSs and N protein sequences in RNA S showed that the Iranian TSWV isolate clustered in cluster I and formed a sister group with isolates from France and Iran. On the other hand, the analysis of RNA S segments revealed that the Iranian TSWV isolate clustered together with isolates from the USA, Turkey, and Italy. Transmission ability of the mixed virus sample was confirmed by mechanical inoculation of pepper and tomato plants. The plants showed a range of symptoms 15–25 days post inoculation (dpi). [ABSTRACT FROM AUTHOR]

NEDD8/RUB, as a ubiquitin-like protein, participates in the post-translational modification of protein and requires unique E1, E2, and E3 enzymes to bind to its substrate. The RUB E1 activating enzyme and E2 conjugating enzyme play a significant role in the neddylation. However, it is unknown whether RUB E1 and E2 exist in pepper and what its function is. In this study, a total of three putative RUB E1 and five RUB E2 genes have been identified in the pepper genome. Subsequently, their physical and chemical properties, gene structure, conserved domains and motifs, phylogenetic relationship, and cis-acting elements were analyzed. The structure and conserved domain of RUB E1 and E2 are similar to that of Arabidopsis and tomato. The RUB E1 and E2 genes were randomly distributed on seven chromosomes, and there were two pairs of collinearity between pepper and Arabidopsis and eight pairs of collinearity between pepper and tomato. Phylogenetic analysis reveals that RUB E1 and E2 genes of pepper have a closer relationship with that of tomato, potato, and Nicotiana attenuate. The cis-elements of RUB E1 and E2 genes contained hormone response and stress response. RUB E1 and E2 genes were expressed in at least one tissue and CaRCE1.3 and CaRCE2.1 were exclusively expressed in flowers and anthers. Moreover, the expression of RUB E1 genes (CaECR1, CaAXR1.1, and CaAXR1.2) and RUB E2 genes (CaRCE1.1, CaRCE1.2, and CaRCE2.1) was increased to varying degrees under low-temperature, drought, salt, ABA, and IAA treatments, while CaRCE1.3 and CaRCE2.2 were down-regulated under low-temperature treatment. In addition, these genes were hardly expressed under MeJA treatment. In summary, this study provides a theoretical foundation to explore the role of RUB E1 and E2 in the response of plants to stress. [ABSTRACT FROM AUTHOR]

Main conclusion: The combination of water and gas at an aeration rate of 15 mg/L and irrigation amount of 0.8 Ep significantly promoted the root morphology, inter-root soil bacterial community structure and diversity of pepper, enhanced the structure of molecular symbiotic network, and stimulated the potential ecosystem function. Poor aeration adversely affects the root morphology of pepper (Capsicum annuum L.) and bacterial community. It is critical to understand the effects of water–air interactions on root morphology and bacterial community structure and diversity. A randomized block experiment was conducted under the two aeration rates of dissolved oxygen mass concentrations, including A: 15 mg/L, O: 40 mg/L, and C: non-aeration as control treatment, and two irrigation rates of W1 and W2 (0.8 Ep and 1.0 Ep). The results showed that aerated irrigation had a significant effect on the root morphology of pepper. Compared with treatment CW1, treatment AW1 increased root dry weight, root length, root volume, and root surface area by 13.63%, 11.09%, 59.47%, and 61.67%, respectively (P < 0.05). Aerated irrigation significantly increased the relative abundance of Actinobacteria, Gemmatimonadetes, Alphaproteobacteria, Gemmatimonas, Sphingomonas, and KD4-96 aerobic beneficial bacteria. It decreased the relative abundance of Proteobacteria, Monomycetes, Bacteroidetes, Corynebacterium, Gammaproteobacteria, Anaerolineae, Subgroup_6, MND1, Haliangium, and Thiobacillus. The Pielou_e, Shannon and Simpson indexes of treatment AW1 were significantly higher than treatments OW1 and CW1. The results of the β-diversity of bacterial communities showed that the structure of soil bacterial communities differed significantly among treatments. Actinobacteria was a key phylum affecting root morphology, and AW1 treatment was highly correlated with Actinobacteria. Molecular ecological network analysis showed a relatively high number of bacterial network nodes and more complex relationships among species under the aeration of level 15 mg/L and 0.8 Ep, as well as the emergence of new phylum-level beneficial species: Dependentiae, BRC1, Cyanobacteria, Deinococcus-Thermus, Firmicutes, and Planctomycetes. Therefore, the aeration of 15 mg/L and 0.8 times crop-evaporation coefficient can increase root morphology, inter-root soil bacterial community diversity and bacterial network structure, and enhance potential ecosystem functions in the rhizosphere. [ABSTRACT FROM AUTHOR]

Background: Pepper is a popular ingredient in many Chinese households; however, anthracnose caused by Colletotrichum spp. has greatly decreased pepper production. The genus Bacillus is widely known for its important role in the development and protection of plants from phytopathogenic fungi. Results: Fifty-eight endophytic strains were isolated from pepper leaves and tested for antifungal activity in this study. Specifically, L1-7 and L3-5 displayed growth inhibition rates of 79 and 80% against C. scovillei mycelium, respectively, while 25 of these strains all had growth inhibition rates of greater than 60%. Bacillus amyloliquefaciens and B. velezensis, based on culture and morphological identification with 16S rDNA and gyrB gene sequence analyses, were determined to be the respective species L1-7 and L3-5. Additionally, it was discovered that these two antagonistic endophytic bacteria could fix nitrogen, produce indoleacetic acid (IAA) and have a high salt tolerance. Pot experiments again showed excellent control of the pathogen C. scovillei by L1-7 and L3-5, with 80.64 and 73.39% control, respectively. Therefore, B. amyloliquefaciens (L1-7) and B. velezensis (L3-5) can be applied as biological control agents to protect peppers against C. scovillei-caused anthracnose. Conclusion: Bacillus amyloliquefaciens (L1-7) and B. velezensis (L3-5) can be applied as biological control agents to protect peppers against C. scovillei-caused anthracnose. Thus, they can serve as promising biocontrol agents and plant growth promoters, and future research on the pertinent bacteria will serve as a useful guide for the creation of microbial resources. [ABSTRACT FROM AUTHOR]

Background: The growth and yield of pepper (Capsicum annuum L.) is often affected by the critical salt stress. Salicylic acid (SA) can improve plants' stress tolerance by promoting growth and regulating ion absorption and transportation. Methods and results: To uncover the alleviated mechanism of salt stress by SA in pepper, we conducted morphological, physiological, cytological, and transcriptomic analyses under a single SA treatment and NaCl with and without SA pre-treatment for 9 days. Seedlings under NaCl treatment showed yellow shrunken leaves, this tatus were alleviated by NS treatment (NaCl with SA pre-treatment). Compared with plants under NaCl treatment, those in the NS treatment showed reduced lipid peroxidation, and significantly increased contents of chlorophyll and osmotic regulators (proline, soluble sugars). Treatment with SA balanced the Na+/K+ ratio. We conducted transcriptome sequencing and identified differentially expressed genes (DEGs) contributing to alleviation of salt stress by SA in pepper. Besides photosynthesis related genes, GO and KEGG analyses revealed that the DEGs were enriched in 'sequence-specific DNA binding', 'transcription regulator activity' and 'DNA binding transcription factor activity' by GO terms. And our results showed that TFs, such as MYB, bZIP, BBX, AP2/ERF, NAC, etc., probably make a great contribution in the alleviation of salt stress by SA. Conclusions: These results reveal that SA can improve plants' stress tolerance by balancing ion absorption, gene expression and transcriptional regulation, which provide new ideas and resources for subsequent research on the mechanism of salt tolerance in pepper. [ABSTRACT FROM AUTHOR]

The contamination of cadmium (Cd) in agro-products causes major concern because of its potential dietary risks. In this study, a total of 647 pepper samples from 21 provinces in China were randomly collected according to the distribution of pepper production. Cd pollution levels in Chinses pepper and its health risks were evaluated based on bioaccessibility, which was measured by the physiologically based extraction test (PBET). The results showed that Cd concentration in all pepper ranged from 0.002 to 1.470 mg/kg, with an average of 0.222 mg/kg and a median of 0.132 mg/kg. The highest daily intake of Cd was observed in the female child group (4.037 × 10−5 mg/kg bw/day), which accounted for 4% of the maximum daily permissible dose – 0.001 mg/kg bw/day. The target hazard quotients of Cd were all lower than 1, indicating low potential non-carcinogenic health risks to residents via the consumption of pepper. Notably, carcinogenic risk values suggested potential adverse health effects to adults, while after considering the bioaccessibility of Cd in pepper (mean of 43.07%), those values had fallen under the acceptable level (1 × 10−4). This may indicate that dietary risk assessment of heavy metals in crops could not be conducted just based on their content; the bioaccessibility of metals is also an important factor for consideration. [ABSTRACT FROM AUTHOR]

In fruits of cultivars of pepper species Capsicum annuum (Sirenevyi Cub), C. frutescens (Samotsvet) and C. chinense (Pimenta da Neyde), which differ in the pigmentation profile during maturation, the content of anthocyanins and the expression pattern of the structural and regulatory genes of anthocyanin biosynthesis were determined. Anthocyanins were found in the fruit of the Sirenevyi Cub cultivar as well as in the peel and pulp of Samotsvet and Pimenta da Neyde cultivars. In the peel of the fruits of all three analyzed cultivars, the levels of expression of structural genes for the biosynthesis of anthocyanins are two or more times higher than in the pulp. In cv. Samotsvet and Pimenta da Neyde, the expression in the pulp of CHS, F3´5´H, DFR, ANS, and UFGT are higher than that of cv. Sirenevyi Cub. The cv. Pimenta da Neyde is characterized by a high expression of structural genes in the pulp and peel of ripe fruit. Expression of transcription factor genes anthocyanin2 (R2R3-MYB) and MYC (bHLH) was detected in the peel of fruits of cv. Sirenevyi Cub as well as in the peel and pulp of fruits of cv. Samotsvet and Pimenta da Neyde at all the analyzed stages of ripening. For all structural genes of the anthocyanin biosynthesis pathway, a high correlation was found (r = 0.54‒0.93) between the expression levels of all anthocyanin biosynthesis structural genes and anthocyanin content in fruits. High correlation (r = 0.88) is also shown for MYC. For the anthocyanin2, correlation (r = 0.85) is present only for cv. Sirenevyi Cub and Pimenta da Neyde but not for cv. Samotsvet. [ABSTRACT FROM AUTHOR]

Peppers are spices consumed all around the world. This study evaluated the physicochemical properties and antioxidant activities of red, orange, yellow, green, and purple peppers. Total capsaicinoids showed the highest concentration in the green pepper (2416.50 µg/g). Vitamin C showed similar concentrations in all peppers (28.90–30.95 mg/g), except for the purple pepper (25.59 mg/g). Chlorophyll was abundant in the green and the purple peppers (280.36 and 102.13 mg/100 g). Total carotenoid was abundant in the red and the orange peppers (237.04 and 276.94 mg/100 g). Total anthocyanin was detected only in the purple pepper (67.13 mg/100 g). Total flavonoid showed a high concentration in the green and the purple peppers (24.27 and 22.27 CAE mg/g). The yellow pepper showed the highest antioxidant activity according to total polyphenol, DPPH radical scavenging activity, ABTS radical scavenging activity and reducing power assays. Therefore, peppers showed potential for the development of functional food materials. [ABSTRACT FROM AUTHOR]

Microspore embryogenesis is widely used in plant breeding to obtain homozygous lines. It is an important way of obtaining haploids and it is valuable for QTL (Quantitative Trailt Locus) mapping and genetic research. We analyzed the microspore embryogenesis ability of 142 recombinant inbred lines (RIL) and mapped QTLs for microspore embryogenesis based on a genetic map constructed using specific-locus amplified fragment sequencing SLAF-seq technology. Results revealed that microspore embryogenesis ability in pepper is a quantitative character. Seven QTLs were detected on linkage groups LG2, LG6, LG8, LG11 and LG12. The peak logarithm of odds (LOD) score of the seven QTLs ranged from 3.51 to 6.66, and the range of phenotypic variation explained by a single QTL ranged from 4.76 to 18.30%. We identified a major QTL, Me2.2, located in the region of 116.5–118.5 cM on LG2; the corresponding physical segment was 166,621,667–167,038,758 bp, and 24 candidate genes were predicted in this region. Functional annotation indicated that these genes are closely related to the initiation of cell division, symmetrical or asymmetric cell division, and other life processes. The study laid a good foundation for further research on the mechanism of microspore embryogenesis. [ABSTRACT FROM AUTHOR]

The spice made from the fruits of Piper nigrum (PN) has economic and medicinal importance. Due to the high demand, as well as export and trade, the quality is threatened by the mixture of cheap and morphologically similar materials, mainly Carica papaya (CP) seeds. The primary objective of this study was to develop a PCR assay to detect CP adulteration and also confirm the presence of PN. For that, PN and CP specific primers were designed from the unique nucleotide sequence regions in the chloroplast genomes of both plants. Sanger sequencing of the specific amplicon revealed that PN primer sequences fall within the region of the rps16 gene and CP primer sequences fall within the region of the trnK-UUU (CP) gene. The designed primers were subjected to optimization of PCR conditions, sensitivity, and cross-reactivity assay. We have sequentially optimised simplex, duplex, and digital PCR (dPCR) to detect the lower quality and quantity of the DNA extracted from blended formulations. The primers for PN and CP were found to be specific and sensitive enough to amplify the target sequence down to 0.1 ng of total genomic DNA. Simplex, duplex, and dPCR assays were able to detect 1.0% (w/w) adulteration of CP seeds in a simulated blended formulation. Thus, the developed primers and assay can be used for the detection of adulteration of CP seeds in PN products. [ABSTRACT FROM AUTHOR]

This study was carried out to address the effects of arbuscular mycorrhizal fungi (AMF) and salicylic acid (SA) on plant growth and the activity of antioxidative enzymes against wilt disease caused by Verticillium dahliae Kleb. (Vd) in pepper. AMF (2.5 g) applications positively affected the development of pepper plants, although SA alone did not cause a significant effect. The combined application of SA and AMF significantly increased shoot length (7.5%) except for the other plant growth parameters. SA combined with AMF suppressed wilting by 42.5% and vascular discoloration by 69.4%. The gallic acid content in pepper plants varied depending on the applications and time after treatment; SA and AMF applications increased gallic acid content compared with the control. These treatments also increased activity of antioxidative enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) in pepper plants compared to the control. [ABSTRACT FROM AUTHOR]

Understanding and prediction of mercury (Hg) phytoavailability in vegetable–soil systems is essential for controlling food chain contamination and safe vegetable production as Hg-contaminated soils pose a serious threat to human health. In this study, four typical Chinese soils (Heilongjiang, Chongqing, Yunnan, and Jilin) with varied physicochemical properties were spiked with HgCl2 to grow sweet pepper (Capsicum annuum L.) in a pot experiment under greenhouse condition. The chemical fractionation revealed a significant decrease in exchangeable Hg, while an increase in organically bound Hg in the rhizosphere soil (RS) compared to bulk soil (BS). This observation strongly highlights the vital role of organic matter on the rhizospheric Hg transformation irrespective of contamination levels and soil properties. Stepwise multiple linear regression (SMLR) analysis between Hg concentration in plants, Hg fractions in RS and BS, and soil properties showed that Hg in plant parts was significantly influenced by soil total Hg (THg) (R2 = 0.90), soil clay (R2 = 0.99), amorphous manganese oxides (amorphous Mn) (R2 = 0.97), amorphous iron oxides (amorphous Fe) (R2 = 0.70), and available Hg (R2 = 0.97) in BS. Nevertheless, in the case of RS, Hg accumulation in plants was affected by soil THg (R2 = 0.99), amorphous Mn (R2 = 0.97), amorphous Fe oxides (R2 = 0.66), soil pH, and organically bound Hg fraction (R2 = 0.96). Among all the evaluated soils (n = 04), metal (mercury) concentration in terms of plant uptake was reported highest in the Jilin soil. Based on SMLR analysis, the results suggested that the phytoavailability of Hg was mainly determined by THg and metal oxides regardless of the rhizospheric effect. These findings facilitate the estimation of Hg phytoavailability and ecological risk that may exist from Hg-contaminated areas where pepper is the dominant vegetable. [ABSTRACT FROM AUTHOR]

Background: Biofumigation is a non-chemical sustainable approach that reshapes soil microbiota to overcome challenges in way of continuous cultivation. However, the type and quantity of substrate have a significant impact on microbiota shifts and the subsequent success of biofumigation. Moreover, studies on the effects of biofumigant concentration in combination with fumigation duration on soil microbiota dynamics are very rare. Research methods: We performed microcosm experiments to investigate how a biofumigant (Korean canola cultivar, HanRa) at various concentrations (0.5%, 1%, 2–4% w/w: biofumigant/soil) and fumigation periods (2–4 weeks) affects the soil bacterial and fungal communities. Subsequently, pot experiments employing two Korean canola cultivars (HanRa and YongSan) at 1% (w/w) were carried out. Results: Illumina MiSeq analysis revealed that 2–4% biofumigant, regardless of incubation period, had a significant negative impact on microbial diversity and network complexity. In contrast, 1% biofumigant transformed the bacterial, fungal, and inter-kingdom networks into a highly connected and complex network without affecting microbial diversity. Bacillus, Clostridium, and Pseudomonas were the most highly stimulated bacterial genera in the biofumigated soils, whereas the abundance of Acidobacteria members was greatly reduced. The 2–4% amendments had substantially and more differentially abundant Fusarium than the 1%. Soil nutrition (e.g., pH, nitrate, ammonium, and exchangeable potassium), fruit yield, and weed suppression were enhanced in subsequent pot experiments. Of the nine soil chemical properties, phosphate and exchangeable potassium were the main factors influencing the microbial community assembly. Conclusions: Optimized biofumigation-mediated increase in nitrate, ammonium, and potassium availability in the soil without causing any negative effects on soil microbial diversity indicates its potential as a preplant to improve crop productivity. This study contributes significantly to our understanding of how an optimal biofumigant can help ameliorate obstacles in continuous cropping. [ABSTRACT FROM AUTHOR]

Aims: Nitrate content in crops might be affected by soil abiotic properties and endophytic and soil microbes. This study aimed to reveal the effects of spent mushroom substrate (SMS) and nitrification inhibitor dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP) on the nitrate content of pepper fruit and to link the nitrate with soil abiotic properties and endophytic and soil bacterial communities. Methods: Our current study contained four different treatments: blank control (CK); sole SMS application (SAA); SMS + DCD (SDCD); and SMS + DMPP (SDMPP). The nitrate contents and bacterial communities in fruit, root and soil samples were quantified and linked. Results: Compared with the CK treatment, the nitrate contents of pepper fruit decreased by 43.2%, 66.8% and 64.4% in the SAA, SDCD and SDMPP treatments, respectively. The combined applications of SMS and nitrification inhibitors significantly enhanced the pH and bacterial community diversity of soil samples. The SMS applications significantly changed bacterial community structures in the soils and roots rather than in the fruit. The relative abundances of aerobic chemoheterotrophy function in the fruit samples were 0.28, 0.17, 0.10 and 0.15 for the CK, SAA, SDCD and SDMPP treatments, respectively. The relative abundances of Bacteroidetes and aerobic chemoheterotrophy were significantly and positively correlated with nitrate contents in the fruit. Conclusions: Apart from promoting fruit yield, the SMS and nitrification inhibitor applications could also decrease the health risk of crop nitrate accumulation via affecting the soil pH, ammonium content and endophytic bacterial community diversity, structures and functions in fruit samples. [ABSTRACT FROM AUTHOR]

The cellulose synthase gene superfamily contains cellulose synthase (CesA) and cellulose synthase-like (Csl) gene families, which synthesize cellulose and hemicellulose in plant cell walls and play a crucial role in plant growth and development. However, the CesA/Csl gene family has not been reported in pepper. Therefore, the genome-wide research of the CaCesA/CaCsl gene family was conducted in pepper. In this study, a total of 39 CaCesA/CaCsls genes (10 CesAs genes and 29 Csls genes) were identified in pepper and unevenly distributed on 11 chromosomes. These CaCesA/Csls were divided into seven subfamilies (CesAs, CslAs, CslBs, CslCs, CslDs, CslEs, CslGs), and most of CaCesA/Csls genes are closely related to AtCesA/Csls genes. The cis-acting elements in the promoters of CaCesA/Csls genes are mainly related to hormone response and stress response. There are ten collinear gene pairs between the CesA/Csls gene family of pepper and Arabidopsis, and four fragment duplication gene pairs of the CaCesA/Csls genes were discovered. RNA-seq analysis shows that the majority of CaCesA/Csls are expressed in a variety of plant tissues, indicating that most CaCesA/Csls gene expression patterns are not organ-specific, and CaCslD1/D4 have the highest expression in anthers, followed by petal, ovary, and F9. RNA-seq analysis shows that most CaCesA/Csls are responsive to five hormones (IAA, GA3, ABA, SA, and MeJA). The tissue-specific expression analysis of the CaCslD1 gene shows that the CaCslD1 gene is expressed specifically in flowers. In the flower buds IV of cytoplasmic male sterility (CMS) and its restoration of fertility (Rf) system, CaCslD1 reach the highest expression respectively. However, the relative expression level of CaCslD1 in the fertile accessions is extremely significantly higher than in the sterile accessions. This study shows an overall understanding of the CaCesA/Csls gene family and provides a new insight for understanding the function of CaCslD1 in pollen development and exploring the fertility restoration of CMS in pepper. [ABSTRACT FROM AUTHOR]

The Fresno-Benavente Pepper (F-BP) Protected Geographical Indication (PGI) is a horticultural crop characterized by its great agronomic, economic and cultural importance in the region of Castilla y León (Spain). Field production is threatened by verticillium wilt caused by Verticillium dahliae and postharvest losses due to grey mould caused by Botrytis cinerea. Eight Bacillus spp. strains endophytically isolated from F-BP roots were used in the study. By conducting an in vitro antagonism study, we found that all Bacillus strains were effective against B. cinerea and five of them showed high antagonism against V. dahliae, with B. siamensis and B. proteolyticus strains being the most effective against both pathogens. Eight Bacillus strains were used for an infection test in F-BP fruits and plants to test their activity against both fungal pathogens. We report that Bacillus thuringiensis, B. siamensis and B. pumilus (SCFC 1–2) could control B. cinerea in pepper fruits through direct action and local activation of plant defences. In the case of V. dahliae root infection, plant roots inoculated with B. siamensis and B. proteolyticus were able to significantly decrease the occurrence of disease through direct action and local activation of jasmonic acid as a defence response. Therefore, we propose that B. siamensis could be used to control B. cinerea and V. dahliae in F-BP fruits and plants, respectively, through direct antagonism as well as the induction of local plant defence responses. [ABSTRACT FROM AUTHOR]

Studies on optimizing the in vitro growth of Capsicum annuum L. are essential for producing hybrids in cases of incompatible crossing. Thus, this study aimed to examine the impact of photosynthetically active radiation (PAR), sucrose concentration, and gas exchange on in vitro growth of C. annuum L. First, sterile seeds were cultivated in flasks with or without sucrose (0 and 20.0 g L−1), PAR intensities (65, 121, and 240 μmol photons m−2 s−1), and flask sealing types (PVC film (PVC), rigid lid (RL), and lids with microporous membrane (M2)). A completely randomized design was used in a 3 × 3 × 2 factorial arrangement of treatments with four replications. For germination, sucrose was not necessary, and the treatment M2, with the highest PAR intensity and no sucrose, promoted optimal shoot and root growth. However, high PAR intensity in microenvironments with limited gas exchange reduced photochemical efficiency. The photochemical efficiency assessed by the Fv/Fm ratio and the performance index were affected by increased PAR intensity and restricted gas exchange. The SPAD index declined with higher PAR intensity, especially without sucrose. At high PAR intensity (240 µmol m−2 s−1), M2 membranes facilitated the growth. Thus, for in vitro C. annuum L. culture, the use of M2 membranes is recommended in combinations of PAR at 65 µmol m−2 s−1 and 20.0 g L−1 sucrose, or with 121 µmol m−2 s−1 PAR with or without sucrose; and 240 µmol m−2 s−1 PAR can be used in medium without sucrose in association with M2 membranes. [ABSTRACT FROM AUTHOR]

Phospholipase C (PLC) is one of the major lipid-hydrolyzing enzymes, involved in lipid-mediating signal pathway. PLCs have been found to play a significant role in the growth and development of plants. In this study, the genome-wide identification and characteristic analysis of CaPLC family genes in pepper were conducted and the expression of two CaPLC genes were investigated. The results showed that a total of 11 CaPLC family genes were systematically identified, which were distributed on five chromosomes and divided into two groups based on their evolutionary relevance. Some cis-elements responding to different hormones and stresses were screened in the promoters of CaPLC genes. Quantitative real-time PCR indicated that the expression of CaPIPLC1 and CaPIPLC5 in flowers were dozens of times higher than in other tissues. In addition, with the development of flower buds, the relative expressions of CaPIPLC1 and CaPIPLC5 gradually increased in fertile materials R1 and F1. However, no expression of CaPIPLC1 and CaPIPLC5 were detected at all developmental stages of cytoplasmic male sterile lines (CMS) compared with fertile accessions. The study revealed the number and characteristics of the CaPLC family genes, which supplied a basic and systematic understanding of CaPLC family. In addition, these findings provided new insights into the role of CaPLC genes in pollen development and fertility restoration in pepper. [ABSTRACT FROM AUTHOR]

Tomato spotted wilt orthotospovirus (TSWV) is one of the most widespread and damaging pepper viruses worldwide. Until recently, disease control has been achieved by breeding pepper cultivars with the resistance gene Tsw. However, the breakdown of Tsw-resistance gene has been increasingly reported from many locations where resistant cultivars have been grown. This has been caused by the emergence of resistance-breaking isolates because of the high evolutionary and adaptative capacity of TSWV. The resurgence of RB TSWV-strains causing heavy production losses in pepper (Capsicum annuum) plants in Turkey has directed the attention to the factors contributing to the outbreak of these serious epidemics. In this paper, we report the first detailed molecular and biological characterization of TSWV-isolates in the field and greenhouse-grown pepper plants. Biological clones from TSWV field samples segregated into three different types of symptoms on pepper plants carrying the Tsw-resistance gene; (i) only local lesions as a result of hypersensitive reaction, (ii) chlorotic rings, chlorosis, vein clearing, downward leaf curling, and stunting, (iii) severe systemic necrosis and wilting leading to the death of resistant plants. The phylogenetic analysis of the NSs gene has shown that the isolates were clustered regardless of the phenotype RB or non-resistance breaking (NRB). Our study has also supported the hypothesis that developing and expanding the RB isolates has occurred locally. The phylogenetic analyses on TSWV-pepper isolates have revealed the fact for the presence of reassortment in TSWV population which might be caused by a mixed infection of TSWV variants. [ABSTRACT FROM AUTHOR]

Capsaicin is a recognized alkaloid that can be used as a flavoring and palatability agent. These effects can increase feed intake in lactating sows during farrowing, especially under thermal stress conditions, and provide antioxidant and immunostimulant activities. The objective of this work was to find out the effects of a capsaicin-based product on the feed intake of sows, immunomodulation, and repercussions on litter performance and the control of piglet diarrhea conditions. A total of 132 pregnant sows and lactating sows and their respective litters were divided into 66 sows each and submitted to one of two possible treatments: a capsaicin-free diet (control group) or capsaicin per meal/day. Capsaicin was mixed with gestation and lactation diets in the proportion of 98.6 g of feed and 1.4 g of capsaicin/kg feed, with the dose administered “on top” of 100 g per treatment day on the first feeding. The sows were treated between 90 days of gestation and 21 days of lactation. Backfat thickness, feed intake during farrowing, colostrum production, IgG colostrum concentration, sow reproductive performance, piglet performance, and diarrhea were evaluated. Compared to the sows in the control group, those that received capsaicin had higher feed intake (+ 0.69 kg/day during lactation, P = 0.008), higher levels of IgG in colostrum (185.75 versus 153.80 mg/mL, P = 0.04), an 11.2% higher litter weight gain, with individual piglet weight gains greater than 5.24% (P = 0.045), and an effective reduction in the frequency of piglet diarrhea on the 10th and 17th days of age (P = 0.013 and P = 0.001, respectively). Capsaicin is an additive with potential effects on the sow’s performance, with positive influences on the health and growth of suckling piglets.Highlights: Sows are challenged by higher prolificity and an increase in temperature. Capsaicin can improve the maternity performance of piglets and increase sow feed intake. Capsaicin can stimulate greater production of immunoglobulins and reduce diarrhea in litters. [ABSTRACT FROM AUTHOR]

Residue analyses were conducted for 283 pesticide active ingredients on pepper samples collected from the local markets (between April and November) of Çanakkale province of Turkey by using QuEChERS method and LC–MS/MS and GC–MS/MS devices. In present pepper samples, 35 different pesticide residues were detected. About 25.0% (27 samples) of present samples had single residue and 43.5% (47 samples) had multiple residues. Of the detected pesticides, acetamiprid, triadimenol, imidacloprid, boscalid, pirimiphos-methyl, tebuconazole, and metalaxyl were the most common ones, while carbendazim/benomyl, fenpropathrin, and thiram were the banned ones. Moreover, 24 of the pesticide residues detected were above the MRL values, 19 pesticides were in the "moderately hazardous (II)," and two pesticides were in the "extremely hazardous (Ib)" class (WHO). Present findings revealed that consumer health may be in danger despite all legal measures by the Ministry of Agriculture and Forestry of Turkey, thus greater emphasis should be put on monitoring of pesticide use and residues. [ABSTRACT FROM AUTHOR]

Fructokinase is the main catalytic enzyme for fructose phosphorylation and can also act as a glucose receptor and signal molecule to regulate the metabolism of plants, which plays an important role in plant growth and development. In this study, the CaFRK gene family and their molecular characteristics are systematically identified and analyzed, and the specific expression of CaFRKs under different tissues, abiotic stresses and hormone treatments were explored. Nine FRK genes were authenticated in pepper genome database, which were dispersedly distributed on eight reference chromosomes and predicted to localize in the cytoplasm. Many cis-acting elements that respond to light, different stresses, hormones and tissue-specific expression were found in the promoters of CaFRKs. FRK proteins of four species including Capsicum annuum, Arabidopsis thaliana, Solanum lycopersicum and Oryza sativa were divided into four groups via phylogenetic analysis. The collinearity analysis showed that there were two collinear gene pairs between CaFRKs and AtFRKs. In addition, it was significantly found that CaFRK9 expressed far higher in flower than other tissues, and the relative expression of CaFRK9 was gradually enhanced with the development of flower buds in fertile accessions, 8B, R1 and F1. Nevertheless, CaFRK9 hardly expressed in all stages of cytoplasmic male sterile lines. Based on the quantitative real-time PCR, most of CaFRK genes showed significant up-regulation under low-temperature, NaCl and PEG6000 treatments. On the contrary, the expression levels of most CaFRKs revealed a various trend in response to hormone treatments (IAA, ABA, GA3, SA and MeJA). This study systematically analyzed CaFRK gene family and studied its expression pattern, which lay the foundation of CaFRK genes cloning and functional verification response to abiotic stresses, and provides new insights into exploring the CaFRK genes on the pollen development in pepper. [ABSTRACT FROM AUTHOR]

Background: Zinc (Zn) deficiency is a widespread problem in reducing the yield and quality of crop plants worldwide. It is important to utilize molecular markers linked to Zn efficiency to develop high Zn efficient cultivars in pepper (Capsicum annuum L.). Methods and results: In present study, genetic map was constructed using a F2 populations derived from C. annuum L. (Alata 21A) × C. frutescens L. (PI 281420) cross. The quantitative trait locus (QTLs) for Zn efficiency were mapped using F2:3 population. A genetic map with 929.6 cM in length and 12 linkage groups were obtained using 62 markers (31 sequence-related amplified polymorphism (SRAP), 19 simple sequence repeat (SSR) and 11 random amplified polymorphic DNA (RAPD) markers). The 41 linked QTLs related with nine (9) Zn efficiency characters were mapped on linkage groups. Results suggest that selecting plants for tolerance to Zn deficiency are expected to be rather responsive among segregating populations for breeding and developing Zn efficient genotypes in pepper. Conclusions: The molecular markers are expected to aid selection and expedite breeding peppers resistant to Zn deficiency in soils low for available Zn contents. [ABSTRACT FROM AUTHOR]

Background and aims: The use of root-associated microorganisms emerge as a sustainable tool to enhance crop tolerance and productivity under climate change, particularly in drought-affected areas. Here, the impact of an inoculum based on arbuscular mycorrhizal fungi (AMF) was evaluated on pepper (Capsicum annuum L.) cultivation at varying water irrigation treatments (well-watered, reduced irrigation and rain-fed) under open-field conditions.Agronomic and ecophysiological parameters, as well as biochemical analyses on stress markers and phytohormones in leaves and on fruit quality traits, were evaluated, along with the shifts in soil- and root-associated microbial communities.Rain-fed water treatment caused reduced fruit sizes, while no differences were detected among well-watered and reduced irrigation. Reduced irrigation did not cause a reduction in stomatal conductance. The highest AM fungal colonization rates were observed under reduced irrigation, and the enhanced flavonoid content and reduced oxidative stress markers in AMF-inoculated plants suggested a synergistic effect of AM fungal inoculation in boosting plant tolerance against stress. A shift in microbial community composition in the different irrigation treatments, associated with different enzymatic activity, highlighted the potential role of microbial dynamics in plant stress response under water-limited conditions.The study suggests that a reduced irrigation comes along with beneficial impacts on pepper root associated microbes, while not impairing crop performance and yields, indicating a potential of saving water. All together, our results imply that optimization of irrigation and beneficial plant–microbe interactions, such as AM fungal symbiosis, can improve pepper physiological and productivity features under climate change.Methods: The use of root-associated microorganisms emerge as a sustainable tool to enhance crop tolerance and productivity under climate change, particularly in drought-affected areas. Here, the impact of an inoculum based on arbuscular mycorrhizal fungi (AMF) was evaluated on pepper (Capsicum annuum L.) cultivation at varying water irrigation treatments (well-watered, reduced irrigation and rain-fed) under open-field conditions.Agronomic and ecophysiological parameters, as well as biochemical analyses on stress markers and phytohormones in leaves and on fruit quality traits, were evaluated, along with the shifts in soil- and root-associated microbial communities.Rain-fed water treatment caused reduced fruit sizes, while no differences were detected among well-watered and reduced irrigation. Reduced irrigation did not cause a reduction in stomatal conductance. The highest AM fungal colonization rates were observed under reduced irrigation, and the enhanced flavonoid content and reduced oxidative stress markers in AMF-inoculated plants suggested a synergistic effect of AM fungal inoculation in boosting plant tolerance against stress. A shift in microbial community composition in the different irrigation treatments, associated with different enzymatic activity, highlighted the potential role of microbial dynamics in plant stress response under water-limited conditions.The study suggests that a reduced irrigation comes along with beneficial impacts on pepper root associated microbes, while not impairing crop performance and yields, indicating a potential of saving water. All together, our results imply that optimization of irrigation and beneficial plant–microbe interactions, such as AM fungal symbiosis, can improve pepper physiological and productivity features under climate change.Results: The use of root-associated microorganisms emerge as a sustainable tool to enhance crop tolerance and productivity under climate change, particularly in drought-affected areas. Here, the impact of an inoculum based on arbuscular mycorrhizal fungi (AMF) was evaluated on pepper (Capsicum annuum L.) cultivation at varying water irrigation treatments (well-watered, reduced irrigation and rain-fed) under open-field conditions.Agronomic and ecophysiological parameters, as well as biochemical analyses on stress markers and phytohormones in leaves and on fruit quality traits, were evaluated, along with the shifts in soil- and root-associated microbial communities.Rain-fed water treatment caused reduced fruit sizes, while no differences were detected among well-watered and reduced irrigation. Reduced irrigation did not cause a reduction in stomatal conductance. The highest AM fungal colonization rates were observed under reduced irrigation, and the enhanced flavonoid content and reduced oxidative stress markers in AMF-inoculated plants suggested a synergistic effect of AM fungal inoculation in boosting plant tolerance against stress. A shift in microbial community composition in the different irrigation treatments, associated with different enzymatic activity, highlighted the potential role of microbial dynamics in plant stress response under water-limited conditions.The study suggests that a reduced irrigation comes along with beneficial impacts on pepper root associated microbes, while not impairing crop performance and yields, indicating a potential of saving water. All together, our results imply that optimization of irrigation and beneficial plant–microbe interactions, such as AM fungal symbiosis, can improve pepper physiological and productivity features under climate change.Conclusion: The use of root-associated microorganisms emerge as a sustainable tool to enhance crop tolerance and productivity under climate change, particularly in drought-affected areas. Here, the impact of an inoculum based on arbuscular mycorrhizal fungi (AMF) was evaluated on pepper (Capsicum annuum L.) cultivation at varying water irrigation treatments (well-watered, reduced irrigation and rain-fed) under open-field conditions.Agronomic and ecophysiological parameters, as well as biochemical analyses on stress markers and phytohormones in leaves and on fruit quality traits, were evaluated, along with the shifts in soil- and root-associated microbial communities.Rain-fed water treatment caused reduced fruit sizes, while no differences were detected among well-watered and reduced irrigation. Reduced irrigation did not cause a reduction in stomatal conductance. The highest AM fungal colonization rates were observed under reduced irrigation, and the enhanced flavonoid content and reduced oxidative stress markers in AMF-inoculated plants suggested a synergistic effect of AM fungal inoculation in boosting plant tolerance against stress. A shift in microbial community composition in the different irrigation treatments, associated with different enzymatic activity, highlighted the potential role of microbial dynamics in plant stress response under water-limited conditions.The study suggests that a reduced irrigation comes along with beneficial impacts on pepper root associated microbes, while not impairing crop performance and yields, indicating a potential of saving water. All together, our results imply that optimization of irrigation and beneficial plant–microbe interactions, such as AM fungal symbiosis, can improve pepper physiological and productivity features under climate change. [ABSTRACT FROM AUTHOR]

Given the aphids high reproductive capacity, assessing their biocontrol by using entomopathogenic fungi is crucial; to determine their potential, fungi were tested in planta and in field conditions. Significant decrease of Myzus persicae (Sulzer) population was observed in planta after applying Beauveria bassiana (strain 7R), Trichoderma gamsii (strain Z) or Metarhizium brunneum (strain Meta Br1) at 1 × 107 or 1 × 108 conidia/mL on pepper plants. Significant differences of aphids' populations were detected between fungus concentration and control (F = 68.743, df = 6.980, P < 0.001), where M. brunneum at 1 × 108 conidia/mL reduced aphids population close to zero. At 20 °C, dead aphids' mycosis by B. bassiana and T. gamsii was 78% and 84%; at 25 °C was 83% and 88%; and at 30 °C was 75% and 79%, respectively. In field conditions, Mexican PTG4 and commercial GHA B. bassiana strains were tested [(1 × 106 conidia/mL + corn starch) seed treatments] against the Melanaphis sacchari (Zehntner) aphid populations, on naturally infested sorghum plants. Results showed that plant germination and emergence were not affected, whereas yield (grams of sugar/plant) was significantly higher among treated compared with untreated plants. The aphid population decreased in plants from PTG4 treated seeds; indeed, this treatment had a significant positive effect on the flowering index, whereas the stem fresh weight and juice volume was significantly increased among plants from GHA treated seeds. Taken together, tested strains can be used as a tool to control aphids' population on several crops such as pepper and even increase the yield in sorghum. [ABSTRACT FROM AUTHOR]

Infection by Sclerotium rolfsii will cause serious disease and lead to significant economic losses in chili pepper. In this study, the response of pepper during S. rolfsii infection was explored by electron microscopy, physiological determination and integrated proteome and metabolome analyses. Our results showed that the stomata of pepper stems were important portals for S. rolfsii infection. The plant cell morphology was significantly changed at the time of the fungal hyphae just contacting (T1) or surrounding (T2) the pepper. The chlorophyll, carotenoid, and MDA contents and the activities of POD, SOD, and CAT were markedly upregulated at T1 and T2. Approximately 4129 proteins and 823 metabolites were clearly identified in proteome and metabolome analyses, respectively. A change in 396 proteins and 54 metabolites in pepper stem tissues was observed at T1 compared with 438 proteins and 53 metabolites at T2. The proteins and metabolites related to photosynthesis and antioxidant systems in chloroplasts and mitochondria were disproportionally affected by S. rolfsii infection, impacting carbohydrate and amino acid metabolism. This study provided new insights into the response mechanism in pepper stems during S. rolfsii infection, which can guide future work on fungal disease resistance breeding in pepper. [ABSTRACT FROM AUTHOR]

Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is a predatory mite, effective at controlling whiteflies and thrips in protected crops. However, on tomato its efficacy as a biocontrol agent is hindered, most probably by the plant trichomes and their exudates. Our aim was to characterize the response of A. swirskii to the tomato trichome exudates and identify three major detoxification gene sets in this species: cytochromes P450 (CYPs), glutathione S-transferases (GSTs) and carboxyl/cholinesterases (CCEs). Mites were exposed separately to tomato and pepper, a favourable host plant for A. swirskii, after which their transcriptional responses were analysed and compared. The de novo transcriptome assembly resulted in 71,336 unigenes with 66.1% of them annotated. Thirty-nine A. swirskii genes were differentially expressed after transfer on tomato leaves when compared to pepper leaves; some of the expressed genes were associated with the metabolism of tomato exudates. Our results illustrate that the detoxification gene sets CYPs, GSTs and CCEs are abundant in A. swirskii, but do not play a significant role when in contact with the tomato exudates. [ABSTRACT FROM AUTHOR]

Corona virus pandemic outbreak also known as COVID-19 has created an imbalance in this world. Scientists have adopted the use of natural or alternative medicines which are consumed mostly as dietary supplements to boost the immune system as herbal remedies. India is famous for traditional medicinal formulations which includes 'Trikadu'—a combination of three acrids, namely Zingiber officinale, Piper nigrum and Piper longum which have antioxidant properties that boost our immune system hence acting as a strong preventive measure. In this study, AutoDock 4.0 was used to study interaction between the phytocompounds of Trikadu with RNA-dependent polymerase protein and enveloped protein of the SARS-CoV-2 virus. Analysis of the results showed that coumarin, coumaperine and bisdemethoxycurcumin showed strong bonding interactions with both the proteins. We can conclude that Trikadu has the potential molecules; hence, it can be incorporated in the diet to boost the immune system as a preventive measure against the virus. [ABSTRACT FROM AUTHOR]

In plants, F1 hybrids showing hybrid weakness exhibit weaker growth than their parents. The phenotypes of hybrid weakness are often suppressed at certain temperatures. However, it is unclear whether hybrid weakness in Capsicum annuum × C. chinense is temperature-dependent or not. Our study showed that Capsicum hybrid weakness was suppressed at 30 and 35 °C and was induced at 15, 20, and 25 °C. Moreover, we investigated the time course of hybrid weakness in cell death, metabolite content, and gene expression in leaves of plants transferred to 20 °C after growing at 30 °C for 21 days. The expression of pathogen defense-related genes was upregulated at 1 day after transfer to 20 °C (DAT). Cell death was detected at 7 DAT, plant growth had almost stopped since 14 DAT, and sugars were accumulated at 42 DAT in hybrid plants. The study revealed that some sugar transporter genes, which had been upregulated since 7 DAT, were involved in sugar accumulation in Capsicum hybrid weakness. Thus, our results demonstrated that gene expression changes occur first, followed by physiological and morphological changes after induction of hybrid weakness. These responses observed in this study in Capsicum hybrid weakness are likely to be owed to plant defense responses-like reactions. [ABSTRACT FROM AUTHOR]

Plant respiratory burst oxidase homolog (Rboh) are key enzymes for reactive oxygen species (ROS) production in plants. They help in resisting adverse environmental conditions and regulating growth and development. To date, many Rboh family members have been identified in plants, but little is known about Rboh genes in pepper. In this study, seven CaRboh genes and six CaRboh genes were identified in 'Zunla-1′ and 'CM334′ pepper genomes, respectively. All CaRboh proteins were predicted to localize to the plasma membrane and were divided into five subfamilies by comparative phylogenetic analysis. A total of fourteen cis-elements were identified in the promoters of CaRboh genes. Synteny analysis of the Rboh proteins of pepper with those of Arabidopsis, tomato, and potato, led to the identification of several orthologous and paralogous genes, which provided further insight into the diversity of the evolutionary characteristics of genes of this family in other plant species. Besides, the expression profiles revealed that CaRbohA, CaRbohB, and CaRbohD genes were highly expressed in all tissues, while CaRbohC, CaRbohF, and CaRbohG genes were expressed at very low levels. The results of physiological indexes and qRT-PCR showed that CaRbohA, CaRbohB, and CaRbohD genes response to stress by mediates H2O2 and O2•−, and then lead to MDA accumulation, implying that the three genes play an important role in response to abiotic stress. This study has laid a foundation for further understanding of the function of Rboh family genes in pepper. [ABSTRACT FROM AUTHOR]