As a crucial member of the gene family involved in the biosynthesis of strigolactones, D27 plays an important regulatory role in plant branching and root development, which is essential for field management and yield increase in peppers (Capsicum annuum L.). To comprehensively understand the characteristics of the pepper D27 gene family, we identified three CaD27 genes. By analyzing their physicochemical properties, phylogenetic relationships, gene structures, promoters, and expression patterns in different tissues, the characteristics of the CaD27 gene family were revealed. The research results showed that these three CaD27 genes are located in three different chromosomes. Evolutionary analysis divided the members of CaD27 into three groups, and gene collinearity analysis did not find any duplicates, indicating the diversity and non-redundancy of the CaD27 gene family members. In addition, we identified and classified cis-elements in the promoter regions of CaD27 genes, with a relatively high proportion related to light and plant hormone responses. Expression pattern analysis showed that CaD27.1 is expressed in leaves, while CaD27.2 is expressed in roots, indicating tissue specificity. Furthermore, protein interaction predictions revealed an interaction between D27.2 and CCD7. This study provided important insights into the function and regulatory mechanisms of the CaD27 gene family and the role of strigolactones in plant growth and development.

Chilling injury (CI) in green pepper fruits during low-temperature storage causes a significant decline in quality. The present study utilized physiological, transcriptomic, and metabolomic analyses to idneitfy the mechanisms by which trypsin mitigates CI in green peppers stored at 4 °C for 8 days, followed by 3 days of shelf life. Results indicated that the trypsin treatment significantly reduced electrolyte leakage and the CI index in peppers, effectively extending their shelf life and preserving postharvest quality. After 4 days of storage, comparative -omic analyses identified 2514 differentially expressed genes (DEGs) and 397 differentially abundant metabolites (DAMs) between trypsin-treated and control peppers. The trypsin treatment induced changes in sugar metabolism, modulating the expression of HK, SUS, INV, and GLGC, which affected the abundance of metabolites such as CDP-glucose and α-D-p-glucose. Trypsin also enhanced carotenoid metabolism, altering the abundance of rhodopinal glucoside, 1\'-hydroxyl-γ-carotene glucoside, and farnesyl 1-PP, and influencing the expression of PDS, CRTH, CRTB, and LUT5. Notably, the trypsin treatment activated the mitogen-activated protein kinase (MAPK) pathway that plays an integral role in the signal transduction of abiotic stress. Differential expression of FLS2, ELF18, PTO, PR1, PTI5, WPKY, MEKK1, and MPK6 genes in the MAPK pathway was observed, which was correlated with CI mitigation in green peppers during cold storage. In conclusion, trypsin is an effective treatment for reducing CI in green peppers during cold storage. The present study provides valuable insights into its physiological and molecular impact on green pepper fruit.

Parthenocarpy, characterized by seedless fruit development without pollination or fertilization, offers the advantage of consistent fruit formation, even under challenging conditions such as high temperatures. It can be induced by regulating auxin homeostasis; PAD1 (PARENTAL ADVICE-1) is an inducer of parthenocarpy in Solanaceae plants. However, precise editing of PAD1 is not well studied in peppers. Here, we report a highly efficient clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) ribonucleoprotein (RNP) for CaPAD1 editing in three valuable cultivars of pepper (Capsicum annuum L.): Dempsey, a gene-editable bell pepper; C15, a transformable commercial inbred line; and Younggo 4, a Korean landrace. To achieve the seedless pepper trait under high temperatures caused by unstable climate change, we designed five single guide RNAs (sgRNAs) targeting the CaPAD1 gene. We evaluated the in vitro on-target activity of the RNP complexes in three cultivars. Subsequently, we introduced five CRISPR/Cas9-RNP complexes into protoplasts isolated from three pepper leaves and compared indel frequencies and patterns through targeted deep sequencing analyses. We selected two sgRNAs, sgRNA2 and sgRNA5, which had high in vivo target efficiencies for the CaPAD1 gene across the three cultivars and were validated as potential off-targets in their genomes. These findings are expected to be valuable tools for developing new seedless pepper cultivars through precise molecular breeding of recalcitrant crops in response to climate change.

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

Bell pepper plants are sensitive to environmental changes and are significantly affected by abiotic factors such as UV-B radiation and cold, which reduce their yield and production. Various approaches, including omics data integration, have been employed to understand the mechanisms by which this crop copes with abiotic stress. This study aimed to find metabolic changes in bell pepper stems caused by UV-B radiation and cold by integrating omic data. Proteome and metabolome profiles were generated using liquid chromatography coupled with mass spectrometry, and data integration was performed in the plant metabolic pathway database. The combined stress of UV-B and cold induced the accumulation of proteins related to photosynthesis, mitochondrial electron transport, and a response to a stimulus. Further, the production of flavonoids and their glycosides, as well as affecting carbon metabolism, tetrapyrrole, and scopolamine pathways, were identified. We have made the first metabolic regulatory network map showing how bell pepper stems respond to cold and UV-B stress. We did this by looking at changes in proteins and metabolites that help with respiration, photosynthesis, and the buildup of photoprotective and antioxidant compounds.

As an important member of mitogen-activated protein kinase (MAPK) cascades, MAPKs play an important role in plant defense response against biotic and abiotic stresses; however, the involvement of the majority of the MAPK family members against Ralstonia solanacearum and heat stress (HS) remains poorly understood. In the present study, CaMAPK1 was identified from the genome of pepper and its function against R. solanacearum and HS was analyzed. The transcript accumulations of CaMAPK1 and the activities of its native promoter were both significantly induced by R. solanacearum inoculation, HS, and the application of exogenous hormones, including SA, MeJA, and ABA. Transient expression of CaMAPK1 showed that CaMAPK1 can be targeted throughout the whole cells in Nicotiana benthamiana and triggered chlorosis and hypersensitive response-like cell death in pepper leaves, accompanied by the accumulation of H2O2, and the up-regulations of hormones- and H2O2-associated marker genes. The knock-down of CaMAPK1 enhanced the susceptibility to R. solanacearum partially by down-regulating the expression of hormones- and H2O2-related genes and impairing the thermotolerance of pepper probably by attenuating CaHSFA2 and CaHSP70-1 transcripts. Taken together, our results revealed that CaMAPK1 is regulated by SA, JA, and ABA signaling and coordinates responses to R. solanacearum infection and HS in pepper.

Chili peppers (Capsicum annuum L.) are economically valuable crops belonging to the Solanaceae family and are popular worldwide because of their unique spiciness and flavor. In this study, differences in the metabolomes of landrace (Subicho) and disease-resistant pepper cultivars (Bulkala and Kaltanbaksa) widely grown in Korea are investigated using a 1H NMR-based metabolomics approach. Specific metabolites were abundant in the pericarp (GABA, fructose, and glutamine) and placenta (glucose, asparagine, arginine, and capsaicin), highlighting the distinct physiological and functional roles of these components. Both the pericarp and placenta of disease-resistant pepper cultivars contained higher levels of sucrose and hexoses and lower levels of alanine, proline, and threonine than the traditional landrace cultivar. These metabolic differences are linked to enhanced stress tolerance and the activation of defense pathways, imbuing these cultivars with improved resistance characteristics. The present study provides fundamental insights into the metabolic basis of disease resistance in chili peppers, emphasizing the importance of multi-resistant varieties to ensure sustainable agriculture and food security. These resistant varieties ensure a stable supply of high-quality peppers, contributing to safer and more sustainable food production systems.

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In tropical countries, combating leaf curl disease in hot peppers has become important in improvement programs. Leaf curl disease is caused by whitefly (Bemisia tabaci) transmitted begomoviruses, which mainly include chilli leaf curl virus (ChiLCV). However, multiple begomoviruses have also been found to be associated with this disease. The Capsicum annuum line, DLS-Sel-10, was found to be a tolerant source against this disease during field screening. In this study, we characterized the resistance of DLS-sel-10 against chilli leaf curl virus (ChiLCV) in comparison to the susceptible cultivar Phule Mukta (PM), focusing on the level, stage, and nature of resistance. Comprehensive investigations involved screening of DLS-Sel-10 against the whitefly vector ChiLCV. The putative tolerant line displayed reduced virus infection at the seedling stage, with increasing resistance during vegetative, flowering, and fruiting stages. Both DLS-Sel-10 and PM could be infected with ChiLCV, although DLS-Sel-10 remained symptomless. Insect feeding assays revealed DLS-Sel-10 as a less preferred host for whiteflies compared to PM. In conclusion, DLS-Sel-10 demonstrated tolerance not only to ChiLCV but also served as an unfavorable host for the whitefly vector. The study highlighted an age-dependent increase in tolerance within DLS-Sel-10, showcasing its potential for effective leaf curl disease management in chilli.

This study aimed to assess the post-harvest dynamics of seedless conical and mini-conical pepper cultivars in terms of fruit weight loss, dry matter content, and soluble solid content. The above parameters were demonstrated to be effective commercial pepper shelf-life indicators. The commercial quality of pepper fruit intended for export was evaluated weekly under simulated fruit storage conditions for over 28 d. Results revealed that fruit weight loss, dry matter content, and soluble solid content were affected by cultivar type and storage duration. Additionally, a strong correlation between these variables was observed confirming their linear relationship which was more profound between dry matter and total soluble solid content. Daily changes during storage were similar in both seedless conical and mini-conical peppers, while the fruit weight loss daily rate was greater than that of dry matter. Water loss was identified to be the main factor causing reduced fruit quality. Solid content reduction occurred predominately during the initial storage period. Notably, fruit with lower dry matter content at harvest tended to maintain their commercial quality for a longer time due to their ability to resist water loss without any visible signs of deterioration, which is beneficial during prolonged storage.