Investigation of Galactinol Synthase Genes in Plant Defense Mechanisms against Adverse Environmental Conditions in Hot Pepper (<i>Capsicum annuum</i>)

Galactinol synthase (GolS) and Raffinose synthase (RS) are key enzymes for the synthesis of Raffinose family oligosaccharides (RFOs) which are widely involved in the growth development and resistances to stresses. To explore the function of HbGolSs  and HbRSs  during leaf development and tapping period in Hevea brasiliensis, in this study, based on the established library data platform of rubber tree genome, we isolated and identified the family members of HbGolSs  and HbRSs , then we analyzed their expression profiles with emphasis through on-line molecular biological tools and PRISM software as well. The results demonstrated that HbGolS1  and HbRS1 were prime member in their separate family, HbGOlS1  was highly expressed in latex and leaf, and with leaf development, its level gradually increased till the ultimate in mature leave, especially, it was dramatically up-regulated by tapping but markedly inhibited by Ethrel treatment; Different from it, HbRS1  was little influenced by tapping or Ethrel treatment although it was specially expressed in latex. Together, this study demonstrated the expression characteristics of HbGolS1 and HbRS1  with leaf development and tapping, which has laid a foundation for further exploring the metabolism of RFOs and their roles in rubber trees.

Raffinose (sucrosylgalactoside oligosaccharide) is a water soluble carbohydrate and accumulates in response to abiotic stresses in plants. Plant raffinose synthases are poorly characterized, and the genes involved in raffinose biosynthesis are unknown in sugar beet. Here, we report the isolation of two genes encoding raffinose synthase (BvRS1 and BvRS2) as well as a gene encoding galactinol synthase (BvGolS1) from sugar beet. BvRS1 and BvRS2 show high homologies to Arabidopsis raffinose synthase AtRS5. BvRS1 and BvGolS1 were expressed in Escherichia coli. Crude extracts showed the activities of raffinose synthase and galactinol synthase. The K m values of BvRS1 for galactinol and sucrose and the K m values of BvGolS1 for UDP-galactose and myo-inositol were determined. The expression levels of BvRS1 were significantly higher than that of BvRS2. The mRNA for BvRS1 was rapidly induced by cold stress whereas the mRNA for BvRS2 was slowly induced by cold and salt stresses. These data suggest that BvRS1 and BvRS2 encode raffinose synthase genes responsible to cold and salt stress, respectively.

SummaryThis study served to reveal the effects and mechanism of low night-temperatures on the metabolism of raffinose-family oligosaccharides in melon (Cucumis melo L.) leaves. We investigated the carbohydrate contents and sugar-metabolising enzyme activities in leaves under normal (15°C; control) and two low night-temperature (12°C or 9°C) conditions during fruit expansion. The results showed that the greatest difference in carbohydrate metabolism occurred between 9°C at night and the 15°C control. Compared to the normal night temperature, total carbohydrate accumulation, in particular raffinose, increased and the ratio of raffinose to total carbohydrates exhibited the greatest increase in melon leaves treated at 9°C at night, while the ratio of sucrose to total carbohydrates declined at the end of the same treatment. These data suggested that 9°C at night played an important role in partitioning carbon from sucrose to raffinose-family oligosaccharides (RFO), and that raffinose may serve dual purposes in stress protection and carbon storage. Meanwhile, the activities of sugar-metabolising enzymes were notably affected by 9°C at night. Sucrose synthase (SS), sucrose phosphate synthase (SPS) and, in particular, galactinol and stachyose synthase activities decreased markedly, while acid invertase (AI) and neutral invertase (NI) activities increased sharply, which restricted sucrose and RFO synthesis. Overall, these data suggest that the decline in stachyose and galactinol synthase activities were the main limiting factor for RFO synthesis in melon leaves at 9°C at night. They also indicated that the reduction in stachyose metabolism may be an important factor during the development of unmarketable fruit.

Capsaicinoids are responsible for the hot taste of chili peppers. They are restricted to the genus Capsicum and are synthesized by the acylation of the aromatic compound vanillylamine (derived from the phenylpropanoid pathway) with a branched-chain fatty acid by the catalysis of the putative enzyme capsaicinoid synthase. R2R3-MYB transcription factors have been reported in different species of plants as regulators of structural genes of the phenylpropanoid pathway; therefore, we hypothesized that MYB genes might be involved in the regulation of the biosynthesis of pungent compounds. In this study, an R2R3-MYB transcription factor gene, designated CaMYB31, was isolated and characterized in Capsicum annuum 'Tampiqueño 74'. Bioinformatic analysis suggested that CaMYB31 could be involved in secondary metabolism, stress and plant hormone responses, and development. CaMYB31 expression analysis from placental tissue of pungent and nonpungent chili pepper fruits showed a positive correlation with the structural genes Ca4H, Comt, Kas, pAmt, and AT3 expression and also with the content of capsaicin and dihydrocapsacin during fruit development. However, CaMYB31 also was expressed in vegetative tissues (leaves, roots, and stems). Moreover, CaMYB31 silencing significantly reduced the expression of capsaicinoid biosynthetic genes and the capsaicinoid content. Additionally, CaMYB31 expression was affected by the plant hormones indoleacetic acid, jasmonic acid, salicylic acid, and gibberellic acid or by wounding, temperature, and light, factors known to affect the production of capsaicinoids. These findings indicate that CaMYB31 is indeed involved in the regulation of structural genes of the capsaicinoid biosynthetic pathway.

Phytophthora blight, caused by the oomycete pathogen, Phytophthora capsici, is a devastating disease on bell pepper and cucurbit crops in the United States and worldwide (29,40). P. capsici causes a root and crown rot, as well as an aerial blight of leaves, fruit, and stems, on bell pepper (Capsicum annuum), tomatoes, cucumber, watermelon, squash, and pumpkin (29,35, 40,57,73). The disease was first described on bell pepper in New Mexico in 1922 (40). In recent years, epidemics have been severe in areas of North Carolina, Florida, Georgia, Michigan, and New Jersey. Oospores are believed to provide the initial source of inoculum in the field, and the disease is polycyclic within seasons (1,7,59,60,67). In this article, we discuss the biology and epidemiology of Phytophthora blight on bell pepper and also describe management strategies that can be implemented based on existing knowledge of the ecology of this devastating pathogen. The objectives of ecologically based pest management (EBPM) are the safe, profitable, and durable management of pests that includes a total systems approach (25). EBPM relies primarily on biological input of knowledge concerning a pathogen life cycle, and secondarily, when necessary, on physical, chemical, and biological supplements for disease management. An understanding of the ecological processes that are suppressive to plant diseases is emphasized rather than secondary inputs (25). Fortunately, we have a considerable amount of information available on the biology and ecology of P. capsici, which can now be integrated to improve our ability to manage the disease using ecologically based approaches. Strategies recommended for management of Phytophthora blight involve integrated approaches that focus first on cultural practices that reduce high soil moisture conditions, but also include monitoring and reduction of propagules of P. capsici that persist in the soil, utilization of cultivars with resistance to the disease, and when necessary, judicious fungicide applications. Symptoms and Life Cycle P. capsici can infect virtually every part of the pepper plant. The pathogen causes a root and crown rot on pepper (Fig. 1) and also forms distinctive black lesions on the stem (Fig. 2). P. capsici can also infect the leaves and causes lesions that are circular, grayish brown, and water-soaked (Fig. 3). Leaf lesions and stem lesions are common when inoculum is splash dispersed from the soil to lower portions of the plant. The pathogen can also infect fruit and causes lesions that are typically covered with white sporangia, a sign of the pathogen (Fig. 4). P. capsici typically causes a fruit rot or stem rot on cucumbers and squash (Fig. 5). P. capsici reproduces by both sexual and asexual means (Fig. 6). The pathogen produces two mating types, known as the A1 and A2. These are actually compatibility types and do not correspond to dimorphic forms. Each mating type produces hormones that are responsible for gametangia differentiation in the opposite mating type. Both A1 and A2 mating types are common in fields in North Carolina and have also been identified within the same plant (59). P. capsici produces a male gametangium, called the antheridium, and a female gametangium, called the oogonium. The antheridium is amphigynous in this species. Meiosis occurs within the gametangia, and plasmogamy and karyogamy result

Identification and characterization of novel microRNAs for fruit development and quality in hot pepper (Capsicum annuum L.)

Galactinol synthase (GolS) is a key initial regulatory enzyme in the synthesis of raffinose family oligosaccharides (RFOs), sugars that play essential roles in plant growth and development. We have cloned the GhGolS1 gene (GenBank accession number: JF813792), which encodes the cotton GolS1 protein by rapid amplification of cDNA ends–polymerase chain reaction (RACE–PCR). The full-length cDNA is 1,729-bp long and encoded an open reading frame (ORF) of 343 amino acids with a deduced molecular weight of 39.2 kDa. The GhGolS1 protein shared 74–78% identity at the amino acid level with GolS isolated from Ricinus communis, Populus trichocarpa, Solanum lycopersicum, Arabidopsis thaliana and Capsicum annuum. The corresponding genomic DNA, which contained three exons and two introns, was isolated and analyzed. The 5′ flanking region was also analyzed to identify a group of putative cis-acting elements. DNA gel blot analysis showed that in the cotton genome, the GhGolS gene family contains at least three members. Real-time PCR (RT-PCR) analysis revealed that GhGolS1 is expressed in cotton leaves, anthers and 35 DPA fibers, and its expression level in anthers is much higher than that in leaves and 35 DPA fibers. It was minimally expressed in other tissues. Additionally, the GhGolS1 protein was localized to the cell membrane. On the basis of these results, we propose that GhGolS1 has critical roles in cotton male fertility, fiber quality and seed development.

Hot pepper (Capsicum annuum) is one of the most consumed vegetable crops in the world and useful to human as it has many nutritional and medicinal values. Genomic resources of pepper are publically available since the pepper genomes have been completed and massive data such as transcriptomes have been deposited. Nevertheless, global transcriptome profiling is needed to identify molecular mechanisms related to agronomic traits in pepper, but limited analyses are published. Here, we report the comprehensive analysis of pepper transcriptomes during fruit ripening and pathogen infection. For the ripening, transcriptome data were obtained from placenta and pericarp at seven developmental stages. To reveal global transcriptomic landscapes during infection, leaves at six time points post-infection by one of three pathogens (Phytophthora infestans, Pepper mottle virus, and Tobacco mosaic virus P0 strain) were profiled. The massive parallel transcriptome profiling in this study will serve as a valuable resource for detection of molecular networks of fruit development and disease resistance in Capsicum annuum.

RNA-Seq experiments allow genome-wide estimation of relative gene expression. Estimation of gene expression at different time points generates time expression profiles of phenomena of interest, as for example fruit development. However, such profiles can be complex to analyze and interpret. We developed a methodology that transforms original RNA-Seq data from time course experiments into standardized expression profiles, which can be easily interpreted and analyzed. To exemplify this methodology we used RNA-Seq data obtained from 12 accessions of chili pepper (Capsicum annuum L.) during fruit development. All relevant data, as well as functions to perform analyses and interpretations from this experiment, were gathered into a publicly available R package: “Salsa”. Here we explain the rational of the methodology and exemplify the use of the package to obtain valuable insights into the multidimensional time expression changes that occur during chili pepper fruit development. We hope that this tool will be of interest for researchers studying fruit development in chili pepper as well as in other angiosperms.

Red chili production in Indonesia has decreased, one of the efforts to increase red chili production is through fertilization techniques. Research on the effect of inorganic fertilizers and liquid organic fertilizers on the growth and yield of red curly chili plants (Capsicum annuum L.) was carried out in August-December 2022 in the experimental field of Tamping Winarno Village, Sukorejo District, Kendal Regency. The aim of the study was to determine the effect of giving inorganic and liquid organic fertilizer concentrations and their combinations on the growth and yield of curly red chili (Capsicum annuum L.). The research method used was arranged in a completely randomized block design (RCBD) with 2 factorial. The first treatment was : concentration of liquid organic fertilizer (N0 = 0 ml, N1 = 10 ml, N2 = 20 ml). The second treatment was: concentration of AB mix fertilizer (P1=1 ppm, P2 = 2 ppm, P3 = 3 ppm). The results of the analysis showed that the concentration of liquid organic fertilizer of 10 ml gave optimal results for plant height parameters. Concentration of inorganic fertilizer (AB mix) 2 ppm gave optimal results on the number of branches parameter. The parameters of the number of fruit planted, the weight of the fruit planted, the weight of fresh stover, and the harvest index did’t significantly affect the treatment of liquid organic fertilizer and inorganic fertilizer (AB mix).

A plant emits diverse volatile compounds and communicates with other organisms at different trophic levels. Hot pepper, Capsicum annuum, leaves produced different compositions of 41 organic compounds upon an infestation by the western flower thrips, Frankliniella occidentalis. These compounds induced a non-preference behavior to the thrips while they attracted a natural enemy, Orius laevigatus. Among the differentially emitted compounds, Z-3-methyl hexenoate (MeH) and linalool repelled the herbivore but attracted the predator. MeH or linalool biosynthesis was suppressed by virus-induced gene silencing of hydroperoxide lyase (HPL) or linalool synthase (LS) expression in the hot pepper and led to significant malfunction in the tri-trophic communication. This communication was mediated by jasmonic acid (JA), but not salicylic acid, signal in the hot pepper. Plant growth-promoting rhizobacteria also induced the antixenosis of hot peppers through JA signaling. Hot peppers resistant against the thrips were positively correlated with HPL or LS expression levels.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-26633-6.

Long non-coding RNAs (lncRNAs) have been shown to play critical regulatory roles in diverse biological processes in plants. However, the presence of lncRNAs and their potential functions in hot pepper are still unknown. Using strand-specific RNA-sequencing, a total of 2505 putative lncRNAs were identified in the fruits of hot pepper. The lncRNAs were transcribed from all pepper chromosomes and 95.37% of them originated from intergenic regions. And 1066 lncRNAs were differentially expressed among the four samples during pepper fruit development. Many potential protein-coding (PC) genes targeted by lncRNAs with cis or trans-acting were also identified. Six of them and their target genes were further validated by quantitative RT-PCR. Some of these target genes were involved in plant hormone signal transduction, cell wall formation and carotenoid biosynthesis, indicating the roles of lncRNAs in the regulation of fruit development and quality. This study identified a large number of lncRNAs in hot pepper, thereby providing some insights into the fruit development of hot pepper.

Background: Vitamins are complex compounds that are needed by the body that function to help regulate or regulate the body's metabolic processes. One of the vitamins needed by the body is vitamin C. Vitamin C is a nutrient that acts as an antioxidant and is effective in overcoming free radicals that can damage cells or tissues, including protecting the lens from oxidative damage caused by radiation. Vitamin C or ascorbic acid is one of the vitamins that is soluble in water, easily oxidized, and sensitive to light stimulation. One of the plants that contain vitamin C is curly red chili. Red chilies have different levels of spiciness. Determination of vitamin C levels in red chili was carried out by UV-Vis spectrophotometry. This study aims: to determine the levels of vitamin C contained in the flesh of curly red chili (Capsicum annum L.) circulating in the Berastagi fruit market, Karo Regency. Methods: The sample used was curly red chili meat obtained from Berastagi fruit market, Karo Regency. The test was carried out by UV-Vis spectrophotometry with a wavelength of 296 nm. Results: The results of research conducted by UV-Vis spectrophotometry obtained an average level of vitamin C in the flesh of red curly chilies of 5.4689 mg/g. Conclusion: The results of the study showed that the flesh of curly red chilies had vitamin C.

An acid invertase (EC 3.2.1.26.) cDNA clone,CaAIV-18, was isolated from the red pericarp cDNA library of the hot pepper (Capsicum annuum L.) fruit. TheCaAIV-18 clone has 2223 nucleotides and one open reading frame encoding 641 amino acid residues. Analysis of deduced amino acid sequences reveals thatCaAIV-18 has a 24-amino acid transmembrane anchor region in its N-terminal, implying acid invertase in hot pepper may be localized in the membrane and not in the cytosol. This clone showed high homology to tomato acid invertase,Aiv1, in nucleotide and deduced amino acid sequences. In the Southern blot analysis, this clone proved to exist as single or low copy numbers on the genome of hot pepper. The clones had two well-conserved regions which appears in acid invertase of other plant species (eg. tomato,Arabidopsis, etc.) and yeasts. During fruit development,CaAIV-18 was expressed preferentially in the ripe red stage.

Cultivars of hot pepper (Capsicum annuum L.) vary greatly in their fruit cadmium (Cd) concentration. Previously, we identified a low-Cd (YCT) and a high-Cd (JFZ) cultivar. In this study, we elucidated the physiological mechanisms resulting in the differences in their Cd accumulation. A time-dependent and concentration-dependent hydroponic experiment was conducted to investigate the difference in root-to-shoot Cd translocation between the two cultivars. Furthermore, a pot experiment was carried out to determine the Cd accumulation in all plant tissues of the two cultivars during fruit development. A greater and more rapid root-to-shoot Cd translocation was observed in JFZ. Moreover, the Cd continuously increased in all plant tissues during fruit development, but following fruit development, the fruit Cd concentration decreased in both cultivars. In each cultivar, the Cd accumulated in the fruit was significantly positively correlated with fruit dry weight. JFZ has a higher ability in Cd translocation from roots to shoots via the xylem. The positive correlation between fruit biomass and Cd content supports that the phloem is the major route for Cd loading into developing hot pepper fruits.