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Abstract The research paper investigates the phytochemicals of watermelon (Citrullus lanatus) as potential novel inhibitors of phosphodiesterase type 5 (PDE5), which is essential for treating erectile dysfunction and pulmonary arterial hypertension. A total of 150 compounds were screened against five PDE5 enzyme structures using molecular docking techniques with Chimera and AutoDock Vina. Interactions were visualized with Chimera and PyMOL, while SwissADME was employed to predict pharmacokinetic properties, and ProTox-II was utilized to assess toxicity. Lunamarine has emerged as a promising candidate for PDE5 inhibition, demonstrating superior pharmacokinetics and favorable toxicity profiles. It exhibited high gastrointestinal absorption and permeability across the blood–brain barrier, potentially outperforming existing inhibitors. The binding energies ranged from − 9.421 to − 9.55 kcal/mol across various PDE5 targets, indicating comparable efficacy. Structural analyses revealed significant hydrophobic interactions with PHE820 and LEU725, as well as hydrogen bonding with TYR612, which are crucial for the formation of the binding pocket. Lunamarine’s effect on catalytic zinc coordination was evidenced by receptor-ligand distances of 3.6 to 3.7 Å. These findings suggest that lunamarine may provide advantages over current therapies, particularly regarding its penetration of the central nervous system. The study recommends further in vitro and in vivo validation of lunamarine's efficacy and safety, as well as an exploration of its potential in other conditions related to PDE5. This research could pave the way for the development of watermelon-derived nutraceuticals for disorders associated with PDE5.

[Objective] This study aims to investigate the mitigation effect and physiological mechanism of salicylic acid (SA) on high temperature stress injury of watermelon seedlings, and to provide a theoretical basis for the application of SA in watermelon cultivation. [Methods] Potted ‘K53’ watermelon seedlings in greenhouse were used as experimental materials. After spraying different concentrations (0, 0.5, 1.0, 1.5, and 2.0 mmol/L) of SA on the leaves, the seedlings were stressed at 42 ℃ for 36 h. The growth characteristics, anatomical structure, physiological and biochemical indexes of watermelon seedlings were observed, and the mitigation effects of each treatment were comprehensively evaluated by membership function method. [Results] After high temperature stress, the leaves of watermelon seedlings were wilted seriously, the growth of root length was inhibited, the leaves became thinner, and the mesophyll cell structure was damaged. After SA application, the leaves became thicker, photosynthetic pigment content, photosynthetic gas exchange parameters, antioxidant enzyme (POD, SOD, CAT) activity and osmotic adjustment substances (proline, soluble sugar, soluble protein) content were increased significantly, while MDA content and relative conductivity were decreased significantly. Compared with the high temperature stress group, the MDA content and relative conductivity of leaves under 1.0 mmol/L SA treatment were reduced by 33.70% and 58.58%, while the contents of chlorophyll a and chlorophyll b, net photosynthetic rate, and the activities of SOD and CAT were increased by 22.71%, 21.63%, 98.34%, 23.98% and 19.71%, respectively. [Conclusion] Pre-spraying SA could alleviate the damage of watermelon seedlings under high temperature stress, with 1.0 mmol/L SA had the best effect.

The current research studied the nutritional and functional properties and antioxidant profile of Cucumis melo and Citrullus lanatus seeds. Results showed that the protein, fat, and fiber content of C. melo seed powder were significantly (p

Innovative superabsorbent hydrogels were synthesized from watermelon rind (WR), an abundant agricultural waste. The process involved free radical polymerization of acrylic acid (AA) and acrylamide (AAm) with WR particles activated by ammonium persulfate (APS), resulting in (AA-co-AAm)/WR hydrogels with high equilibrium swelling capacities of 749 ± 32 g/g. Notably, after eight cycles, the WR hydrogel maintained 94.88 % of its initial swelling capacity, significantly outperforming the (AA-co-AAm) hydrogel without WR (13.80 % retention). This durability, combined with excellent water retention across various soil textures and high adsorption capacity for methylene blue (MB), underscores the WR hydrogel as a superior soil moisture conservation agent. This study marks a significant advance in recycling organic waste and enhancing water management in agricultural soils, demonstrating the potential for sustainable hydrogel development.

Indiana cultivates approximately 7000 acres of watermelons (Citrullus lanatus) every year, with the majority of production concentrated in southern Indiana, thus making this region a key area for watermelon production in the United States. Diverse irrigation and fertilization practices are used for watermelon production in the region, yet their effects on production outcomes remain poorly understood. To address this knowledge gap, this study investigated the impact of existing practices on watermelon yield to optimize irrigation and fertilization practices for improved production. The experiment was conducted at the Southwest Purdue Agricultural Center, Vincennes, IN, USA, during the 2022 and 2023 watermelon seasons. The following four treatments were applied: high irrigation, low irrigation, no irrigation, and fertigation. The fertigation treatment received the same water application as the high irrigation treatment, but with frequent fertilizer application with irrigation; however, fertilizers were applied before planting in the high, low, and no irrigation treatments. Although soil moisture levels at the different depths varied notably among treatments, no significant differences in yield by weight were observed. The minimal impact of irrigation on watermelon yield suggested that sufficient water is stored in the soil to prevent yield-reducing stress during dry periods. However, the high irrigation and fertilization treatments produced more fruit than the low irrigation and no irrigation treatments. The dry periods during both years coincided with the watermelon fruit-setting stages, potentially contributing to the lower fruit set in the low irrigation and no irrigation treatments. Fertigation showed a higher early yield in 2022 than that of the other treatments. An analysis of soil and tissue nitrogen levels indicated that solely applying nitrogen before planting could lead to excessive soil nitrogen during vegetative growth. This excess nitrogen might delay flowering and harvest. This project offers insights into enhancing irrigation and fertilization practices for watermelon production in southern Indiana, provides recommendations, and discusses future research directions.

Continuous application of chemical fertilizers in plant cultivation can lead to the deterioration of the soil environment, resulting in reduced crop yield and quality. Currently, organic fertilizers, such as vermicompost, can partially replace chemical fertilizers and maximize yields while maintaining soil fertility. However, the effects of chemical fertilizers combined with vermicompost on watermelon (Citrullus lanatus) yield and quality are unclear. A field experiment was carried out on the watermelon cultivar Lihua No. 6. Six treatments were applied: no fertilizer (CK, control, 0N–0P–0K), 100% chemical fertilizer [CF, 5.4N–1P–5.4K (256, 47, and 255 kg·ha−1)], 75% chemical fertilizer + 25% organic fertilizer [A1, 5.4N–1P–5.4K (192, 35, and 191 kg·ha−1) + 2250 kg·ha−1 vermicompost], 50% chemical fertilizer + 50% organic fertilizer [A2, 5.4N–1P–5.4K (128, 24, and 127 kg·ha−1) + 4500 kg·ha−1 vermicompost], 25% chemical fertilizer + 75% organic fertilizer [A3, 5.4N–1P–5.4K (64, 12, and 64 kg·ha−1) + 6750 kg·ha−1 vermicompost], and 100% organic fertilizer (A4, 9000 kg·ha−1 vermicompost). Indices related to the growth, yield, and quality of watermelons were determined. Compared with CK, chemical fertilizer alone or in combination with organic fertilizers significantly increased growth parameters (plant height and leaf area) and chlorophyll content. The five fertilizer treatments enhanced the single fruit weight, yield, and biomass. In addition, the yield of reduced chemical fertilizer plus organic fertilizer was comparable to that of watermelons treated with CF. Compared with CF, the fertilizer treatments, especially the 1:1 mixture of chemical and organic fertilizer (A2) group, had elevated fruit-soluble solids and soluble sugar content, and reduced organic acid levels. Therefore, a combination of 50% chemical fertilizer and 50% organic fertilizer can effectively enhance the yield and quality of watermelons. These findings have important implications for guiding the management of watermelon fertilization and development of sustainable agriculture.

Lateral branching is an important agronomic trait in horticulture plants. The aim of this project was to reveal the genetic mechanism, map the gene localization, and predict candidate genes of watermelon lateral branching. An F2 segregating population was derived from a cross between the multibranched maternal inbred line M6 and the branchless paternal inbred line N7. Two DNA pools were constructed using 20 multibranched plants and 20 branchless plants from the F2 population. Whole-genome resequencing was performed for the DNA pools (25×) and the parents (30×) to identify the genomic region associated with lateral branching. Candidate genes were predicted based on the gene annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses; then, quantitative validation of these genes was performed. The results showed that the clean reads of four samples yielded 64,295,076 to 81,658,958 bp, with sufficient genome coverage and high quality. Based on single-nucleotide polymorphism and insertions/deletions association analyses, the candidate genes were mapped to a 2.01-Mb region on chromosome 4 (22,958,925–24,971,894 bp) containing 182 annotated genes. During the KEGG and GO enrichment analyses, these genes were annotated to 10 cellular components, 10 molecular functions, and 12 biological processes. Eight candidate genes responsible for the branchless phenotype in watermelon were identified: Cla97C04G076340, Cla97C04G075820, Cla97C04G076060, Cla97C04G076250, Cla97C04G076280, Cla97C04G076380, Cla97C04G076830, and Cla97C04G075950. These genes were involved in amino acid biosynthesis and catabolism, TCP transcription factor activity, and regulation of flower development. This study offers valuable insights into the molecular mechanisms governing the branchless phenotype in watermelon. These candidate genes serve as potential targets for gene cloning and marker-assisted selection of watermelon cultivars without lateral branches.

CRISPR/Cas9 is a powerful genome editing tool for trait improvement in various crops; however, enhancing mutation efficiency using CRISPR/Cas9 in watermelon and melon remains challenging. We designed four CRISPR systems with different sgRNA expression cassettes to target the phytoene desaturase (PDS) gene in melon. The constructed vectors were delivered to host plants using Agrobacterium-mediated transformation. Phenotypic and genotypic analyses of the edited melon seedlings revealed that the CRISPR systems with tRNA and Csy4 spacers driven by the Pol II-type promoter significantly improved mutation efficiency, reaching 25.20% and 42.82%, respectively. Notably, 78.95% of the mutations generated by the Csy4 system involved large-fragment deletions (LDs) between the two target sites. In watermelon, the Csy4 system achieved a PDS editing efficiency of 41.48%, with 71.43% of the edited seedlings showing LD between the two target sites. Sequencing analysis indicated that the edited melon seedlings exhibited heterozygous, three-allele mutation and chimeric events; the edited watermelon seedlings included 2/14 homozygous mutations. Compared to the commonly used Pol III promoter, using the Pol II promoter to drive sgRNA expression cassettes containing Csy4 showed the best improvement in CRISPR/Cas9 editing efficiency in melon; this system was also effective in watermelon.

Watermelon (Citrullus lanatus L. Thunb. Matsum. and Nakai) is a vegetable species with high water content that is rich in lycopene and refreshing; therefore, breeding studies are carried out intensively to develop new varieties. The breeding period in these plants can be shortened with the use of the haploidization technique, and determining the ploidy levels of plants in haploidization studies is very important. In this study, it was examined whether morphological and cytological analyses would be sufficient for ploidy determination of haploid plants obtained by ovary culture in watermelon. With this aim, the stomatal, morphological and cytological characteristics were determined, taken from 15 haploid and 19 double haploid plants. The ploidy level of the plants was detected by flow cytometry before these analyses. In this study, “Principal Component Analysis” was performed based on average values to analyze the structure of the relationship between the parameters examined. It is thought that stomatal features can be used as morphological markers in determining the ploidy levels of plants. The differences obtained from the study results may help to develop effective strategies in determining the ploidy levels of plants.

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (Fon) is a serious disease in watermelon cultivation. Most of commercialized watermelon cultivars to Fusarium wilt are susceptible in Korea. Fon isolates were divided into four races (races 0, 1, 2, and 3), based on pathogenicity in four watermelon differentials including ‘Sugar baby’, ‘Charleston gray’, ‘Calhoun gray’ and ‘PI-296341-FR’. We obtained 7 isolates of Fon and tested to determine race of the fungal strains. Fon KACC 40902 and Fon HA were race 0 and Fon NW1, Fon NW2, Fon CW and Fon KACC 40901 were race 1. And Fon KACC 40905 was race 2, but race 3 isolate of Fon was not founded. We also tested virulence of seven Fon isolates on three-susceptible cultivars of watermelon. The isolates showed different virulence on the cultivars. In addition, to study the resistance characteristics of watermelon to Fon, we selected three moderately or highly resistant cultivars of watermelon and occurrence of Fusarium wilt in seedlings of the cultivars by seven Fon isolates was investigated. Among them, ‘Calhoun gray’ is highly resistant to six Fon isolates except Fon KACC 40905. On the other two cultivars, disease severity of Fusarium wilt caused by each isolate was positively correlated with the virulence of the Fon isolates. The results suggest that resistance of the watermelon cultivars to Fon isolates is likely affected by the virulence of the pathogen.

This publication is intended to provide information on the disease bacterial leaf spot of cucurbits, its epidemiology, and management to cucurbit growers in the southeastern United States. Written by Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones, and published by the UF/IFAS Plant Pathology Department, March 2024.

This publication is intended to provide information on the disease bacterial leaf spot of cucurbits, its epidemiology, and management to cucurbit growers in the southeastern United States. Written by Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones, and published by the UF/IFAS Plant Pathology Department, March 2024.

ABSTRACT Watermelon has great importance due to its nutritional properties. The aim of this work was to study accessions classified as resistant to fusariosis. Twelve accessions and two cultivars, Sugar Baby and Charleston Gray (controls), were characterized for watermelon fruit quality descriptors. The experiment was conducted in Petrolina-PE, over two production cycles in a randomized complete block design, with three repetitions and five plants per plot. Two fruits per plot were sampled for characterization. Ten quantitative and seven qualitative descriptors were evaluated. For the qualitative traits, dissimilarity measures were determined by a matrix of Euclidean distance. At the second harvest, most accessions had higher organic acid and vitamin C content in the pulp and higher soluble solids (°Brix) content. The accessions were divided into four groups according to the Tocher method. There is variability among the evaluated accessions, and the accessions BGH-Univasf 40, BGH-Univasf 169, and BGH-Univasf 177 are potential sources for use in watermelon breeding programs. Accessions BGH-UNIVASF 76, BGH-UNIVASF 128, and BGH-UNIVASF 185 (Citrullus lanatus var. citroides) performed well in terms of total production, fruit mass, and vitamin C content.

ABSTRACT The use of substances that can mitigate the harmful effects of salt stress is a promising alternative for the use of saline water, especially in semi-arid regions. The aim of this study was to evaluate the effect of different concentrations of hydrogen peroxide in mitigating salt stress in the mini watermelon grown in a hydroponic system. The study was carried out in a greenhouse, in an area belonging to the Federal University of Campina Grande, Pombal, Paraíba. The experimental design was completely randomised using a split-plot factorial scheme with four levels of electrical conductivity for the nutrient solution-ECns (2.1, 3.1, 4.1, and 5.1 dS m-1) considered the plots, and four concentrations of hydrogen peroxide-H2O2 (0, 20, 40, and 60 μM) the subplots, with five replications. The foliar application of hydrogen peroxide in concentrations of between 17 and 20 µM mitigated the effects of salt stress on stomatal conductance, the rate of CO2 assimilation, carboxylation efficiency, and carotenoid content in the mini watermelon up to an ECns of 5.1 dS m-1. Foliar application of hydrogen peroxide in concentrations greater than 20 µM intensified the effects of salt stress on gas exchange and the synthesis of photosynthetic pigments in the mini watermelon. Furthermore, there was an increase in electrolyte leakage in the leaf blade.

ABSTRACT The objective of this research was to evaluate leaf temperature, and watermelon yield components under wetted area percentages (PW) in irrigation located in the Agreste region of Northeastern Brazil. Two experiments were carried out in 2018 and 2019. The adopted statistical design was randomized blocks, with six replications and four treatments, in 2018: P1 = 13%, P2 = 14%, P3 = 19%, and P4 = 22%, in 2019: P5 = 12%, P6 = 15%, P7 = 16%, and P8 = 21% of PW. The meteorological variables analyzed were: air temperature (Ta) and rain. The experimental evaluations consisted of measuring the temperature of the plant’s vegetative canopy, tensiometry, mass, and BRIX. Air temperature was not a limiting factor for watermelon growth and development. The average was 195.88 mm, and the average leaf temperature of watermelon is 29.5 °C, a value lower than Ta. There was no statistically significant difference for fruit mass and BRIX, where the overall mean was 10.82 and 10.46 kg, respectively. Therefore, it is feasible to irrigate watermelon with wetted area percentages ranging from 12 to 22%, in localized irrigation systems, without generating physiological damage and reducing agricultural productivity and fruit quality.

Globally, there has been an increase in stringent regulations governing the use of chemical soil fumigants for controlling diseases, pests, and weeds. Grafting has been identified as an effective alternative to soil fumigation for managing soilborne diseases and pests in intensive vegetable cropping systems. The majority of watermelon (Citrullus lanatus) grafting research confirms that selected rootstocks play a role in improving plant resistance or tolerance to common soilborne diseases. Currently, there is a lack of evidence-based literature on the effects of grafting on watermelon fruit quality attributes and yield components. Previous reviews report wide variation in the impact of grafting on watermelon production, depending on rootstock–scion combinations and environmental conditions. This review employed evidence-based synthesis methods to comprehensively and methodically summarize research results of the impact of grafting on watermelon, with a focus on fruit quality and yield. In this systematic review, 548 citations (studies published during 2011–21) were screened against strict inclusion criteria, and data were extracted from 47 studies. Meta-analysis of percent differences between the grafted watermelon treatment and the nongrafted or self-grafted watermelon control was performed using extracted data of yield components and a wide range of fruit quality attributes. Meta-analysis of research data with variance measures was also conducted based on a rather limited number of studies. Our findings showed higher levels of total yield, average fruit weight, fruit length and width, fruit lycopene and soluble solids content, rind thickness, flesh firmness, lightness, chroma, and flesh nitrogen (N) content in grafted watermelon treatments compared with the nongrafted or self-grafted control. In particular, total yield, average fruit weight, and flesh firmness exhibited significant increases of a more than 10% difference. In contrast, grafted plants demonstrated decreases in fruit pH, hue angle, and flesh calcium content, although the reduction was not greater than 10% relative to the control. Meta-analysis of research data with variance measures further confirmed significantly greater total yield and flesh N content in grafted watermelon treatments compared with the nongrafted or self-grafted control. In addition, the meta-analysis results confirmed greater benefits of watermelon grafting in the presence of known soilborne disease pressure in contrast to the production scenarios without soilborne disease problems.

Se realizó el experimento en Itacurubí de la Cordillera, Paraguay, desde julio de 2021a enero de 2022, donde se evaluó el efecto de la aplicación foliar de un extracto de estevia (Stevia rebaudiana Bertoni) y de un bioestimulante comercial formulado con agua y miel conteniendo 4,05x108UFC.mL-1deLactobacillussp.yde Saccharomycessp., y 3,1x109UFC.mL-1de Streptomyces scabies, comparados con un testigo, sobre el rendimiento de sandía variedad Crimson Sweet. Se utilizó el diseño experimental de bloques completamente al azar con cuatro repeticiones. La primera aplicación de los tratamientos se realizó en el semillero, cuando la plántula contenía 8 hojas definitivas, luego del trasplante, se realizó una aplicación cada 8 días hasta completar 10 aplicaciones en total. Se evaluó el peso promedio de los frutos, el número de frutos por planta y el rendimiento. Los datos fueron sometidosa un análisis de varianza (ANAVA), cuando hubo diferencias significativas entre las medias de los tratamientos, se aplicó la prueba de comparación de medias de Tukey al 5% de probabilidad de error. Con el extracto de estevia se obtuvo 1,9 frutos por planta, con peso promedio de 10 kg y rendimiento de 9119 kg.ha-1, mientras que con el bioestimulante comercial se obtuvo 1,6 frutos por planta, con peso promedio de 8,3 kg y rendimiento de 7325 kg.ha-1. Con el testigo se obtuvo 0,9 frutos por planta con 4,6 kg y un rendimiento de 4044 kg.ha-1. El extracto de estevia ofrece una mayor productividad en el cultivo de sandía. Se sugiere la realización de más estudios para evaluar diferentes dosis de los extractos y considerar variables relacionadas a la fitosanidad y a la calidad postcosecha

Latar Belakang: Dislipidemia merupakan keadaan dimana kadar biokimia lipid didalam tubuh berada dalam rentang abnormal. Dislipidemia dapat berpotensi untuk menimbulkan penyakit seperti aterosklerosis dan penyakit jantung koroner. Daging buah kelapa serta daging putih buah semangka diketahui memiliki senyawa antioksidan yang dapat mencegah dislipidemia. Tujuan: Penelitian ini bertujuan untuk membuktikan potensi pemberian kombinasi daging buah kelapa dan daging buah semangka dapat menginhibisi parameter metabolik pada kondisi dislipidemia. Metode: Penelitian ini adalah penelitian eksperimental berdesain post-test only with control group design yang melibatkan 5 kelompok dengan 25 ekor tikus Wistar perlakuan dengan induksi dislipidemia dengan menggunakan kuning telur puyuh. Perlakuan dilanjutkan dengan intervensi jus daging kelapa atau jus daging putih semangka atau kombinasi keduanya; dan 1 kelompok kontrol dengan induksi dislipidemia dengan kuning telur puyuh yang dilanjutkan dengan intervensi akuades. Durasi intervensi dilakukan selama 28 hari dengan pengambilan darah dilakukan di hari ke-29. Uji kadar profil lipid dilakukan dengan menggunakan plasma darah. Analisis data diawali dengan uji shapiro-wilk yang dilanjutkan dengan uji one-way ANOVA. Hasil: Tidak ada perbedaan yang signifikan pada hasil LDL, trigliserida, dan kolesterol total antar kelompok (p>0,05) dan perbedaan HDL yang signifikan antar kelompok (p

Variations in soil nutrients can influence the nutritional attributes of crops. Therefore, this study was conducted to evaluate the effects of varying sowing depths (2-8 cm) at 2 cm intervals on the nutritional contents of Luffa cylindrica (LC), Citrullus lanatus (CL) and Citrullus colocynthis (CC) fruits. Proximate, mineral and vitamin contents of seeds and pulps of fruits of the plants were determined. Protein (31.10±0.17 %), crude fibre (4.48±0.02 %), fat (47.13±0.27 %), ash (2.50±0.01 %) and carbohydrate (99.66±0.03 %) were higher (p

The objectives of this study is to investigate the phytoremediation potential of watermelon (Citrullus lanatus) seedlings planted on lead contaminated soil in Katsina, Nigeria using appropriate standard methods of physicochemical properties of the soil before and after the experiment and Atomic Absorption Spectrophotometer (AAS) measurements for Pb concentrations. The result revealed that the plant had accumulated a significant concentration of Lead in the leaves (18.112mg/kg), shoot (14.221mg/kg) and roots (9.100mg/kg) and there was no significant difference in the concentrations of Lead used in the study at p>0.05. The phytoextraction ability of C. lanatus was assessed in %remediation factor (RF), Bioconcentration factor (BCF) and elemental translocation factor (TF). The amount of Lead in the shoots and roots after 6weeks showed that more concentration of Lead was translocated from the roots to the leaves. The results of this investigation suggests that Citrullus lanatus could be used for phytoextraction of Lead from contaminated soil.

For most food crops the identity and efficiency of pollinators across key growing regions remains a significant knowledge gap that needs to be addressed before we can develop crop-specific approaches for pollination service delivery. Here, we conducted a systematic literature review and meta-analysis on watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai)), a globally important fruit crop, to identify the floral visitors and their efficiency across different growing regions. We found that 265 insect species visit watermelon flowers (including 5 orders, 18 families and 75 genera) across 17 countries and 6 continents. Bees and flies were the most abundant flower visitors overall, but show distinct regional differences. Honey bees were the majority visitor in 53% of growing regions (range: 0 – 94%), whilst wild bee species were more abundant in 42% of regions (range: 3.4 – 100%). Honey bees and other bees were equally effective at depositing pollen on stigmas, but varied in effectiveness for fruit set and seed set. Pollination data from global studies appear to be limited for the largest-scale watermelon producers, namely: China, Turkey, and India, with the majority (56%) of data available from North America. This synthesis identified four key themes for improving pollination in watermelon: increasing honey bee densities on crops where local polices and environmental conditions are suitable; introducing other managed pollinators; identifying key wild pollinator taxa to encourage within crops; and improving local and landscape management practices to support pollinators.

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is a cucurbit with high value in Burkina Faso. It is appreciated for its fruits, which are widely consumed. In the literature, watermelon is described as an important source of bioactive compounds beneficial to health. There is very little scientific data on this supposed nutraceutical potential of the watermelon. This study aimed to characterize the nutraceutical and antioxidant potential of the pulp of five watermelon cultivars grown in Burkina Faso to identify the best cultivars for consumers. The study focused on the physicochemical, nutraceutical, and antioxidant activity characterization of the cultivars using standard methods. This study revealed a significant variation in total phenolics, flavonoids, β-carotene, and lycopene contents between the five cultivars while the color did not show significant variation. The color parameters with ΔE ranging from 40.62 ± 4.87 (SB cultivar) to 48.90 ± 15.81 (KK cultivar) determined did not reveal any significant difference between cultivars. For the phytochemical parameters: total phenolic compounds, total flavonoids, β-carotene, and lycopene, the cultivars KK and KA showed the highest content. The statistical analysis of the results shows positive correlations between phytochemical composition and pulp color. The color could thus, depending on the cultivar and its maturity, constitute a preliminary indicator of choice for the estimation of the content of bioactive compounds.

Eating watermelon (Citrullus lanatus) is a traditional part of the Fourth of July holidays in the United States; however, growing watermelon in Missouri, USA for the local Fourth of July market requires an early growing season start (beginning of April) under protected culture because of low temperatures and the risk of freezing. Therefore, ‘Yellow Doll’ watermelon production was investigated under low tunnel (LT) and caterpillar high tunnel [HT (walk-in movable two-row tunnel)], and the economic feasibility was assessed by marginal analysis for both protected cultures. Planting in early April allowed harvest to start 1 to 2 weeks before the target market date. In addition, yield increased under HT in comparison with LT and open field (Op). Marginal analysis under the conditions of this study and prices obtained from local farmers’ markets showed a positive marginal rate of return for HT in comparison with the control Op. The marginal rate of return sensitivity study suggests that differences in marketable yield of 300–400 and 200–250 lb/1200 ft2 are necessary under HT and LT, respectively, for the protected culture to be economically feasible with watermelon prices above $0.75/lb and/or $1.00/lb as obtained in local farmers’ markets. Therefore, it is possible and there is potential to produce watermelon under protected culture for the local Fourth of July market. A gain in market share with potential premium prices for watermelon may increase the sustainability of small and medium-size specialty crop farmers in Missouri. To accomplish this, it is necessary to use early cultivars (70 to 80 days to maturity), plant in early April with transplants grown in greenhouses, and make sure to manage tunnels properly to maintain favorable growing conditions, protect against freezing temperatures and ensuring good pollination.

Abstract The objective of this study was to evaluate the water status, photosynthetic pigments, and photochemical efficiency of mini watermelon plants under salt stress and phosphate fertilization. The experiment was conducted in pots under greenhouse conditions in Pombal, PB, Brazil. The experimental design used was randomized blocks in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1) and four doses of phosphorus (60, 80, 100, and 120% of the recommendation), with three replicates. The relative water content in the tissues decreased with the increase in ECw levels in all phosphorus doses, with decreases of 7.05, 7.81 and 8.83% per unit increase in ECw, in plants fertilized with 80, 100 and 120% P2O5. On the other hand, ECw levels increased electrolyte leakage, regardless of phosphorus doses of the recommendation. The synthesis of photosynthetic pigments and the quantum efficiency of photosystem II were inhibited by increasing water salinity from 0.3 dS m-1 in plants grown under phosphorus doses above 60% of the recommendation. Water salinity from 0.3 dS m-1 reduced chlorophyll b contents, initial, maximum, and variable fluorescence of mini watermelon plants, with a decrease of 11.86, 4.51, 4.53, and 4.54% per unit increment of ECw, respectively.

The flesh color of watermelon is an important trait that is determined by carotenoid composition and affects consumers’ fruit desirability. Although a complete dominant control by C locus (Cllcyb) for canary yellow flesh (CY) over red flesh has been reported, red and CY colors frequently appear as a mixed pattern in the same flesh (incomplete canary yellow, ICY) in F1 and inbred lines carrying dominant C alleles. Therefore, we examined the genetic control of the mixed color pattern in ICY using whole-genome resequencing of three ICY (ICY group) and three CY inbred lines (CY group), as well as genetic linkage mapping of an F2 population. The segregation pattern in 135 F2 plants indicated that CY is controlled by a single locus (named C2) dominant over ICY. The whole-genome resequencing of ICY and CY inbred lines revealed an ICY/CY-specific region of approximately 27.60–27.88 Mb on Chr. 2 that was polymorphic between the ICY and CY groups. Our genetic map, using nine cleaved amplified polymorphic sequence markers developed based on the single-nucleotide polymorphisms from the ICY/CY-specific region, confirmed that C2 is located on Chr. 2 and cosegregated with the marker (M7) derived from a non-synonymous single-nucleotide polymorphism of the pentatricopeptide repeat (PPR) gene (ClPPR, Cla97C02G039880). Additionally, 27 watermelon inbred lines of ICY, CY, and red flesh were evaluated using previously reported Cllcyb (C locus)-based markers and our C2 locus-linked ClPPR-based marker (M7). As a result, dominant alleles at the C2 locus were required to produce CY, in addition to dominant alleles at the C locus, while a recessive homozygous genotype at the C locus gave the red flesh irrespective of the genotype at the C2 locus. Using a ClPPR-based cleaved amplified polymorphic sequence developed in this study and Cllcyb-based markers, watermelon cultivars with CY, ICY, and red flesh could be successfully discerned, implying that the combined use of these markers will be efficient for marker-assisted selection of flesh color in watermelon breeding.

No semiárido do Nordeste do Brasil, a irregularidade de chuvas e elevada evapotranspiração proporcionam déficit hídrico nas plantas na maior parte dos meses do ano, destacando-se como fator limitante para produção de olerícolas. Assim, a identificação de estratégias capazes de amenizar os efeitos do déficit hídrico nas plantas é essencial para produção sob condições irrigadas. Nesse contexto, objetivou-se avaliar o efeito da adubação nitrogenada na morfofisiologia e nos componentes de produção de mini-melancia 'Sugar Baby'. O experimento foi conduzido na Fazenda Experimental ‘Rolando Rivas Castellón’, São Domingos, Paraíba, sob condições de casa de vegetação, utilizando-se o delineamento de blocos casualizados em esquema fatorial 4 × 4, correspondendo a quatro níveis de reposição hídrica (50, 75, 100 - controle e 125% da evapotranspiração real da cultura - ETr) e quatro doses de nitrogênio - DN (50, 75, 100 e 125% da dose recomendada), com 3 repetições, totalizando 48 plantas. Foram avaliadas as variáveis de trocas gasosas, os teores de pigmentos fotossintéticos, o conteúdo relativo de água e o extravasamento de eletrólitos, o crescimento e a produção de fitomassa, os componentes de produção e a qualidade pós-colheita dos frutos de mini-melancia. A irrigação deficitária com 50% da evapotranspiração real inibiu as trocas gasosas, a síntese de pigmentos fotossintéticos, o crescimento, e a qualidade dos frutos da mini-melancieira ‘Sugar Baby’, independente da dose de nitrogênio. A lâmina de água com 125% da evapotranspiração real combinada à adubação de 100% da recomendação de nitrogênio proporcionou maiores teores de clorofilas totais, número de folhas e de fitomassa seca das raízes, caule, total, parte aérea e pH dos frutos de mini-melancieira ‘Sugar Baby’.

Citrullus lanatus (Thunb.) is an important crop in Brazil and affected by relevant insect vectors, including thrips (Thysanoptera: Thripidae). The present work was focused on evaluating the presence of Groundnut ringspot virus (GRSV) associated with Frankliniella sp. (Thysanoptera: Thripidae) in watermelon, C. lanatus, cultivated in the Brazilian Cerrado biome. Several species of thrips were collected from four commercial crops located in Gurupi, Lagoa da Confusão, Formoso do Araguaia and Porto Nacional counties, all of them belonging to the Brazilian state of Tocantins). The total viral RNA obtained from the thrips was enriched and used to perform ugh RT-PCR. Using specific primers, a 644 bp fragment of the GRSV nucleocapsid was identified in all insect samples, which allowed us to perform a phylogenetic analysis with GRSV sequences described for other geographical regions. The findings demonstrate the wide distribution of the GRSV virus in commercial watermelon crops in the Brazilian Cerrado Biome. The association with Frankliniella sp. is highlighted as one of the most relevant vector pathways in this region of high intensity and advanced agriculture. In addition, phylogenetic analysis demonstrated a close relationship between GRSV sequences from South Africa and Brazil. These findings may contribute to the understanding of GRSV distribution in watermelon crops in different localities of Brazilian Cerrado Biome.

This study focuses on employing solvent extraction to extract and characterize watermelon (Citrullus lanatus) seed oil. The physicochemical properties of the oil were investigated to assess its potential applications in the food, cosmetic, and pharmaceutical industries. The extraction process yielded an oil content of 43%. The oil exhibited a pH value of 4.02, refractive index of 1.452 at 25 °C, and specific gravity of 0.934 at 15 °C. The boiling point, cloud point, flash point, and melting point of oil were determined as 326 °C, 7.3 °C, 289 °C, and 2 °C, respectively. The oil's viscosity was measured as 0.04072 Pa.s, and it demonstrated a non-sooty flame nature and solubility in ether. The free fatty acid contents and acid value were determined at 3.339 % and 6.678 mg KOH/g, respectively. The saponification value (S.V) and iodine value (I.V.) were 147.6315 mg/KOH/g and 88.526 mg Iodine/g, respectively. Additionally, peroxide value was 16.40 meq peroxide/g, and the oil exhibited a congealing temperature range of -14 °C to 22 °C. The oil's retention factor during chromatography was determined as 1.6 cm. Fourier-transform infrared (FTIR) analysis revealed the presence of functional groups such as hydroxyl, amine, aliphatic hydrocarbon, carbonyl, carbon-nitrogen bond, and sulfoxide groups in the oil. These findings suggest that the presence of functional groups, such as hydroxyl, amine, aliphatic hydrocarbon, carbonyl, carbon-nitrogen bond, and sulfoxide groups in watermelon oil, indicate its potential suitability for a wide range of applications in the food, cosmetic, and pharmaceutical industries.

El programa de la carrera de la Facultad de Ingeniería en Sistemas de Producción Agropecuaria (FISPA), se basa en la adquisición de competencias. Una de las estrategias de enseñanza aprendizaje utilizada es el aprendizaje situado. Un tipo de metodología usada por los docentes, para que los estudiantes enfrenten situaciones reales, o cercanas a sus ámbitos profesionales. El proyecto educativo se realizó durante el periodo febrero – julio de 2022, en el regreso a clases post pandemia Covid-19, en el módulo agrícola demostrativo (sección 1) de FISPA. El proyecto consistió en el establecimiento y manejo agronómico-fitosanitario del cultivo de sandía variedad Jubilee, por 32 alumnos de las experiencias educativas de fundamentos de fitopatología y fitosanidad. Como resultado el 84.3% de los alumnos adquirieron competencias, en la identificación y diagnóstico de enfermedades fúngicas (damping off, mildiu, tizón temprano, tizón tardío y antracnosis). El 87.5% de los alumnos aprendieron a establecer un cultivo desde el acondicionamiento del terreno, siembra de la semilla, trasplante de la planta y establecimiento del riego a partir de las necesidades del cultivo. Se concluye que el aprendizaje situado, favorece el logro de aprendizajes significativos que lleva al estudiante de FISPA de los saberes teóricos a los prácticos, creando un ambiente de liderazgo, trabajo colaborativo y aprendizaje que favorece la adquisición de competencias que le permitirán al estudiante enfrentar y resolver problemas similares en su campo profesional.

Postharvest storage conditions frequently affect nutritional quality of fruits and vegetables. Temperature and storage duration are the most important factors to extend shelf life and maintain quality of fresh watermelon. This study was conducted to determine the changes in the antioxidant properties of watermelon during storage. Fruits of the watermelon cultivars were harvested and stored at 5ºC for a period of 15 days. During storage antioxidant contents (lycopene and total phenolics) and total antioxidant activity were evaluated. The objective of this work was to determine the content of the antioxidant properties in different watermelon genotypes at four different postharvest storage periods (0, 5, 10 and 15 days). Furthermore, the nutritional quality is strongly influenced by the storage period. The cv Mahdia was the most suitable for extended storage periods.

Polyethylene mulch is widely used for vegetable production in the United States as a tool to conserve water, control weeds, and produce earlier and cleaner products (i.e., less attached soil). However, the increasing labor costs for mulch removal and disposal after harvest and soil environmental pollution are major concerns. The objective of this study was to assess fruit yield and quality, mulch deterioration, soil microbial activity, and nutrient changes in ‘Stargazer’ watermelon (Citrullus lanatus) grown with degradable plastic mulch. The deterioration rates of degradable mulch were 7%, 37%, 57%, and 92% after 120, 210, 300, and 365 days, respectively, of placing the mulch in the field. However, the extra difference in using degradable mulch was calculated as $58.6/acre (polyethylene $600.9/acre vs. degradable $659.5/acre), including all costs associated with laying and disposing. One year after placing mulch in the field, the nitrate content and total and active fungi numerically increased (P = 0.08) in soils with the degradable mulch compared with polyethylene mulch. However, there were no statistical differences in soil phosphorus, potassium, organic carbon, and total and active bacteria. Extra-large fruit size yield (category >24.0 lb) from the polyethylene mulch treatment was higher than that from degradable mulch, whereas the 18.0- to 24.0-lb category was lower than that with degradable mulch. However, total yield and total soluble solids from both mulches were statistically similar. Considering the complete deterioration (less waste), mulch removal cost (not required), microbial associations (higher fungi abundance and activity), and similar yield and fruit quality of degradable mulch compared with polyethylene, the implementation of degradable mulches in commercial watermelon field practices is promising.

This context presents the study of ultrasonic-assisted extraction (UAE) to obtain phenolic and flavonoid compounds from watermelon rind powder (WRP). The antioxidant activity of the extracts was investigated using DPPH and ABTS+ assays. One-factor experiments were conducted to examine the effect of each factor (solid-to-liquid ratio (SLR), acetone concentration (AC), temperature, and time) on the UAE of WRP. Box-Behnken Design (BDD) model was employed to optimize the UAE conditions based on total phenolic contents (TPC), total flavonoid content (TFC), and their antioxidant activities. The optimal conditions were 1:30.50 SLR, 70.71% AC, 29.78 °C, and 10.65 min extraction time. There were no significant differences between predicted and experimental results (less than 6.0%), recommending a feasible and innovative process of deploying UAE to extract phenolics and flavonoids effectively from watermelon rind.

Citrullus lanatus (watermelon) which was only cultivated in Northern Nigeria in the past, is now cultivated in other parts of Nigeria. However, there is no data to show the nutritional quality of C. lanatus as it relates to the location of cultivation. Therefore, this study aimed to evaluate the nutritional properties of the pulp of Citrullus lanatus cultivated in four states, representing four geopolitical regions of Nigeria. C. lanatus samples were collected from the northeast, southwest, southeast and south-south geopolitical zones of Nigeria. They were thoroughly washed, then the pulp was separated, homogenized and freeze-dried. The amino acid profile, vitamins, proximate and mineral analyses of the freeze-dried samples were done by standard protocols. The amino acid profile results showed the presence of varied amino acids in the different zones, with the southwest giving the highest concentrations of the amino acids and the least concentration obtained from the south-south zone. The presence of vitamin C and A, and the minerals: Ca, Mg, K, Na, Fe, Pb, and Mn were detected in the pulp of C. lanatus at diverse concentrations in the various zones, with samples from the southwest zone also giving the highest composition of both vita by mins and mineral contents. The proximate composition analysis results revealed a higher (p < 0.05) percentage of moisture, protein and fiber from the southwest sample when compared with other zones, and higher (p < 0.05) percentage composition of carbohydrate, ash and fat contents from the northeast samples relative to other zones. Thus, the nutritional value of the C. lanatus samples was in the order: Southwest > northeast > southeast > south-south. Conclusively, the results showed that the location of cultivation affects the nutritional value of Citrullus lanatus fruit.

Melatonin, a multifunctional signaling molecule, has been shown to play a significant role in response to abiotic stress. Several species have been reported to unveil melatonin’s effect on osmotic stress; however, the signal transduction mechanism of phytohormone-mediated melatonin biosynthesis in plant species remains unclear. In this study, although plants can biosynthesize melatonin, the exogenous application of melatonin to watermelon cells can improve cell growth in response to osmotic stress by regulating the antioxidant machinery of cells. Regarding the melatonin synthesis pathway, ClOMT (ClASMT and ClCOMT) is a multi-gene family, and ClSNAT has two members. Both ClOMTs and ClSNATs harbor the cis-elements in their promoter regions responding to various hormones. Among abscisic acid (ABA), methyl jasmonate (MeJA), and salicylic acid (SA), ABA treatment observably upregulated the expression of ClOMTs and ClSNATs, and the accumulation of melatonin with ABA treatment reached a level comparable to that with osmotic stress by mannitol treatment. Furthermore, when hormone biosynthesis inhibitors were added to cells before osmotic stress, the expression of ClOMTs and ClSNATs, as well as melatonin accumulation, were significantly suppressed with the ABA biosynthesis inhibitor. This study demonstrated the crucial role of melatonin biosynthesis in response to osmotic stress via plant hormone signal transduction. It showed that ABA signaling plays a dominant role in melatonin synthesis under osmotic stress.

One of the most important crops of the Mediterranean, watermelon (Citrullus lanatus), is almost exclusively established through seedlings. For many years, agronomists, nurseries, and farmers have aimed to produce and use high-quality seedlings for better growth in the field. However, seedling quality has not been examined as to what defines the subsequent plant, flower, and fruit development, and to what extent. Our aim was to test whether different seedling qualities labeled as “Optimum”, “Acceptable”, or “Not Acceptable” for cultivation actually perform variably in terms of vegetative, flowering, and fruit development, as well as fruit quality after a full growing cycle in the field. Vegetative growth (stem diameter, plant area, and leaf number) was evaluated until flowering and was enhanced for Optimum plants. The flowering of Not Acceptable plants started two days later, while Optimum plants retained a greater number of female flowers throughout the two-week blooming evaluation. Most importantly, Optimum plants developed mature fruits four and six days faster than the Acceptable and Not Acceptable ones, respectively, showing considerable yield earliness. The photosynthetic mechanism, as well as fruit morphology and phytochemical content, were not affected by quality categories. Overall, indeed it is important to use high-quality seedlings to achieve yield earliness of watermelon fruits.

Abstract Despite the benefits of a diverse approach to crop pollination, global food production remains reliant on a low diversity of managed pollinators, especially the European honey bee (Apis mellifera). To facilitate more robust pollinator management and improve the resilience of the production system, it is necessary to understand regional variation in the pollination ecology of global food crops. Watermelon (Citrullus lanatus [Thunb.] Matsum & Nakai) is a highly insect pollinator‐dependent crop and even though it is grown globally across many different climate zones, little is known about its pollination ecology across the diverse growing regions of Australia, spanning from the tropics to the arid zone. We compared the species composition, visitation rates and effectiveness of the dominant floral visitors on 15 farms across five major watermelon‐growing regions of Australia. We found that insect species composition differed significantly among regions, but honey bees were the dominant watermelon flower visitor, with relative abundance varying from 73% to 94%. However, native bees (including stingless bees Tetragonula sp., and bees from families Megachilidae and Halictidae such as Lasioglossum, Homalictus and Lipotriches) and flies (particularly Syrphidae sp.) also visited and transferred pollen onto watermelon flowers. In particular, native stingless bees were common visitors in several growing regions and deposited similar amounts of pollen to honey bees. Our findings indicate that the Australian watermelon industry utilizes honey bees, but the diverse assemblage of available native pollinating taxa provides an additional opportunity for growers in specific growing regions. Pollination service delivery could be increased by deploying managed populations (e.g., native stingless bee colonies), employing pollinator‐safe land management practices as well as exploring methods for increasing the efficiency of managed honey bee colonies.

Macrophomina phaseolina (Tassi) Goid is the causal agent of charcoal rot and vine decline in cucurbits such as watermelon. Molecular methods have been used for rapid identification. However, a large number of steps used reduces its applicability. This study aimed to detect M. phaseolina in watermelon from producing areas in Northeastern Brazil by direct PCR. Plant tissue samples were collected from seven producing areas and the DNA was extracted using the CTAB method. Amplifications were performed by direct PCR using the MpKFI/MpKRI primers, then the PCR products were subjected to agarose gel electrophoresis and sequenced. Amplicons of 350 bp were observed in stem tissue samples from three areas. The identity of the samples was confirmed by sequencing. This study represents the first molecular diagnosis of M. phaseolina associated with watermelon in Northeastern Brazil. The methodology presented here can be applied for a reliable and simple diagnosis of the pathogen in other crops.

Abstract Background Kinesin (KIN) as a motor protein is a versatile nano-machine and involved in diverse essential processes in plant growth and development. However, the kinesin gene family has not been identified in watermelon, a valued and nutritious fruit, and yet their functions have not been characterized. Especially, their involvement in early fruit development, which directly determines the size, shape, yield and quality of the watermelon fruit, remains unclear. Results In this study, we performed a whole-genome investigation and comprehensive analysis of kinesin genes in C. lanatus. In total, 48 kinesins were identified and categorized into 10 kinesin subfamilies groups based on phylogenetic analysis. Their uneven distribution on 11 chromosomes was revealed by distribution analysis. Conserved motif analysis showed that the ATP-binding motif of kinesins was conserved within all subfamilies, but not the microtubule-binding motif. 10 segmental duplication pairs genes were detected by the syntenic and phylogenetic approaches, which showed the expansion of the kinesin gene family in C. lanatus genome during evolution. Moreover, 5 ClKINs genes are specifically and abundantly expressed in early fruit developmental stages according to comprehensive expression profile analysis, implying their critical regulatory roles during early fruit development. Our data also demonstrated that the majority of kinesin genes were responsive to plant hormones, revealing their potential involvement in the signaling pathways of plant hormones. Conclusions Kinesin gene family in watermelon was comprehensively analyzed in this study, which establishes a foundation for further functional investigation of C. lanatus kinesin genes and provides novel insights into their biological functions. In addition, these results also provide useful information for understanding the relationship between plant hormone and kinesin genes in C. lanatus.

The plant compact and dwarf growth habit is an important agronomic trait when breeding watermelon (Citrullus lanatus) cultivars because of their reduced vine length, high-density planting, and better land utilization; however, the genetic basis of the dwarf growth habit is not well-known. In this study, the plant population of six generations, P1, P2, F1, F2, BC1P1, and BC1P2, were studied. A genetic segregation analysis demonstrated that dwarfism is mainly controlled by a single recessive Cldw gene. Furthermore, whole-genome sequencing of two distinct watermelon cultivars, W1-1 (P1) and 812 (P2), was performed and preliminarily mapped through a bulked segregant analysis of F2 individuals that revealed the Cldw gene locus on chromosome 9. Two candidate genes, Cla015407 and Cla015408, were discovered at the delimited region of 43.2 kb by fine mapping, and gene annotation exposed that the Cla015407 gene encodes gibberellic acid 3β-hydroxylase protein. In addition, a comparative analysis of gene sequence and cultivars sequences across the reference genome of watermelon revealed the splice site mutation in the intron region of the Cldw gene in dwarf-type cultivar 812. The quantitative real-time polymerase chain reaction exhibited a significantly higher expression of the Cla015407 gene in cultivar W1-1 compared with 812. There was no significant difference in the vine length of both cultivars after gibberellic acid treatment. In brief, our fine mapping demonstrated that Cla015407 is a candidate gene controlling dwarfism of watermelon plants.

With the increasing number of cosmetic consumers emphasizing value consumption and sustainability, upcycling has gained attention as a solution to agricultural by-products, which are the main culprits of environmental problems. In this study, we isolated citrulluside T with whitening activity from discarded Citrullus lanatus stems and investigated the anti-melanogenic effect of citrulluside T and the underlying mechanisms. We found that citrulluside T did not exhibit cytotoxicity up to a concentration of 90 μM and significantly reduced the melanin content and intracellular tyrosinase activity in B16F10 cells. In addition, citrulluside T inhibited the expression of melanogenic enzymes such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2, as well as melanin synthesis via cAMP-dependent protein kinase (PKA)/cAMP response element-binding protein (CREB)-mediated downregulation of microphthalmia-associated transcription factor (MITF), a key transcription factor in melanogenesis. Furthermore, we found that citrulluside T exerted its anti-melanogenic effect by downregulating the β-catenin protein and upregulating phosphorylated β-catenin. Finally, we confirmed that citrulluside T was safe for skin through skin irritation tests on 33 subjects, suggesting its applicability as a protective agent against hyperpigmentation for topical applications such as cosmetics and ointments.

Abstract Background Fruit flesh color in watermelon (Citrullus lanatus) is a great index for evaluating the appearance quality and a key contributor influencing consumers’ preferences. But the molecular mechanism of this intricate trait remains largely unknown. Here, the carotenoids and transcriptome dynamics during the fruit development of cultivated watermelon with five different flesh colors were analyzed. Results A total of 13 carotenoids and 16,781 differentially expressed genes (DEGs), including 1295 transcription factors (TFs), were detected in five watermelon genotypes during the fruit development. The comprehensive accumulation patterns of carotenoids were closely related to flesh color. A number of potential structural genes and transcription factors were found to be associated with the carotenoid biosynthesis pathway using comparative transcriptome analysis. The differentially expressed genes were divided into six subclusters and distributed in different GO terms and metabolic pathways. Furthermore, we performed weighted gene co-expression network analysis and predicted the hub genes in six main modules determining carotenoid contents. Cla018406 (a chaperone protein dnaJ-like protein) may be a candidate gene for β-carotene accumulation and highly expressed in orange flesh-colored fruit. Cla007686 (a zinc finger CCCH domain-containing protein) was highly expressed in the red flesh-colored watermelon, maybe a key regulator of lycopene accumulation. Cla003760 (membrane protein) and Cla021635 (photosystem I reaction center subunit II) were predicted to be the hub genes and may play an essential role in yellow flesh formation. Conclusions The composition and contents of carotenoids in five watermelon genotypes vary greatly. A series of candidate genes were revealed through combined analysis of metabolites and transcriptome. These results provide an important data resource for dissecting candidate genes and molecular basis governing flesh color formation in watermelon fruit.

Grafted watermelon plants available in the United States are typically transported for a long distance from a specialized nursery to the production field. To investigate the effects of chilling stress during transportation on the early plant growth and development, grafted and nongrafted ‘Tri-X-313’ seedless watermelon (Citrullus lanatus) seedlings were subjected to low-temperature treatments applied over a 72-hour period. The first experiment exposed grafted and nongrafted seedlings to 0, 6, 12, 24, or 48 hours of 1 °C chilling, and then were moved to a 12 °C growth chamber for the remainder of the chilling treatment period. The second experiment exposed nongrafted seedlings to seven different combinations of chilling duration (0, 24, 32, 41, 44, or 48 hours) to create varied chilling degree hours (CDH) at different temperatures (between −0.4 °C and 1.2 °C). After 72 hours, seedlings were transplanted in pots filled with a commercial substrate in a greenhouse to evaluate the early plant growth and floral development. Each experiment had two repeats (spring and summer) with a randomized complete block design (n = 10). Although greater exposure to chilling negatively affected visual quality and photosynthetic capacity [measured by chlorophyll fluorescence parameter, variable fluorescence/maximum fluorescence (Fv/Fm)] in both repeats, delay in flowering after transplanting was significant in spring only and increased with increasing CDH (up to 6 days with 48 hours of 1 °C exposure). Grafting was found to mitigate the degree of flowering delay when the same chilling exposure was applied. When chilling temperatures were varied, visual damage of leaves, decrease in Fv/Fm, and delays in female flower development were best correlated with CDH at a base temperature of 15 °C, 3 °C, and 4 °C, respectively. Our experiments and further analyses with available literature data suggest that 50 to 70 CDH4 [CDH with base temperature (BT) = 4 °C] seems to be a critical threshold to cause significant delay in female flower development (3.5 days for grafted and 1.3 days for nongrafted plants). Therefore, if temperatures lower than 4 °C are expected during transportation of seedlings, we suggest mitigation measures be taken so that CDH4 do not reach greater than 50 degree hours.

Substrates is an important pillar of seedling production, when it seeks to establish vigorous plants with a uniform pattern and lower possible production costs. The objective of this work was to evaluate the use of the carnauba agroindustrial residue (RC) in the alternative substrate composition for the formation of watermelon seedlings. The experiment was conducted at the Campus Professor Cinobelina Elvas, Federal University of Piauí, Bom Jesus, Piauí. A randomized block design with five treatments was used: RC and sand, in the proportions: 20/80, 40/60, 60/40, 80/20 and 100/0, with four replications and eight plants per plot, 160 plants. The variables evaluated were: emergence percentage, emergence speed index, plant height, leaf area, leaf number, shoot dry mass, neck diameter, root density, root area, root mean length and root dry mass. The seedlings with 100% RC provided higher height (4.43 cm), leaf area (16.13 cm2), number of leaves (2.0) and shoot dry mass (0.13 g / plant). The use of 80% CR and 20% sand resulted in a larger diameter of the neck (mean), root area (mean) and root mean (average) length. Already in the proportions of 60 and 40% of CR plus sand respectively, they promoted higher root density (mean). However, to produce seedlings of Citrullus lanatus with adequate quality standard, it is recommended to use 100% RC substrate because it is more responsive to aerial part and substrate with 80% RC / 20% sand, which promotes greater growth of the system root.

Watermelon (Citrullus lanatus) is an economically important cucurbit (Cucurbitaceae) crop cultivated globally for its nutritional benefits. Fruit development in watermelon is characterized by fast fruit expansion attributed to unique biological processes. Myeloblastosis (MYB) family genes play important roles in plant growth and development, especially R2R3-MYB-type genes. However, the evolution of R2R3-MYB family genes in the watermelon genome and whether they participate in the regulation of watermelon fruit development remain unknown. To address these questions, duplication modes of R2R3-MYB family genes were identified and their expression profiles were investigated during watermelon fruit development. A total of 48 duplicated gene pairs were identified among the 89 R2R3-MYBs in watermelon. Segmental and transposed duplication events play major roles in the R2R3-MYB family gene expansion process. The ratio of nonsynonymous mutation and synonymous mutation analysis indicated that all the duplicated R2R3-MYBs experienced negative selection. Gene structures and cis-element compositions in promoter sequences exhibited abundant divergences between the R2R3-MYB duplicated genes. Transcriptome analyses of seed, rind, and flesh during fruit development showed that only two duplicated gene pairs had significantly similar expression patterns, whereas divergent expression profiles were found between the remaining duplicated gene pairs. Tissue-specific and development stage-specific divergent expression patterns demonstrated that neo-functionalization occurred between watermelon R2R3-MYB duplicated genes. The current study provides valuable information for further functional analyses of R2R3-MYBs in watermelon.

Abstract Citrulline is a non-essential amino acid, involved in key biological functions in plants and humans. Rootstocks have a major impact on citrulline accumulation in grafted watermelon. Information regarding rootstock induced changes in citrulline metabolism is elusive. To understand the regulatory mechanism, parallel changes in the expression profiles of citrulline metabolic genes and citrulline content of watermelon were monitored during the development of self-rooted watermelon and watermelon grafted onto pumpkin, wild and bottle gourd rootstocks. Results demonstrated that rootstocks regulated the expression profiles in different ways to influence the citrulline content. GAT, NAGPR, ASS3 ASS2 and Asl2 showed the negative correlation with citrulline content in pumpkin grafted watermelon. Pumpkin rootstock promoted the citrulline content by high down-regulation and synergistic effect of ASS2, ASS3, ASL1 and ASl2 genes. In wild grafted watermelon, citrulline was accumulated as a result of down regulation of GAT, NAGS and ASL2 genes, which showed an inverse correlation with citrulline. In gourd grafted watermelon, changes in citrulline content were observed to be linked with lower expressions of GAT, NAGK, ASS2, ASS3, ASL1 and ARG which were negatively correlated with citrulline content. Our study will provide the basis to understand the molecular mechanism of citrulline accumulation in various rootstocks.

Citrullus lanatus seed is an important but neglected seed rich in essential fatty acids. The study sought to investigate in silico and in vivo antifungal activity of some bioactive compounds of Citrullus lanatus (watermelon) seed oil (CLSO) on oral candidiasis induced by Candida albicans in immunosuppressed female albino rats and to predict the Absorption, Distribution, Metabolism and Excretion (ADME) properties of isolated natural compound. Docking studies was performed using standard procedure, standard microbiological and histopathological techniques was employed for study of in vivo antifungal activity of the oil; as well as renal function tests at days 7 and 14 post-infection treatments. Treated groups were compared with that of the control groups. In vitro studies showed varied zone of inhibitions at different concentrations. Ligand-protein interaction showed better binding activity between Palmitic acid and SAP-5 as well as CYP51 when compared with fluconazole (reference drug). Treatment with CLSO showed that there was a significant reduction in the kidney fungal burden (cfu/ml/g) of rats treated with CLSO after 14 days post-infection treatment, compared to group 2 (untreated control) rats. Histomorphology of group 2 showed multifocal aggregation and widespread distribution of fungal blastospores when compared with CLSO-treated groups, which had minimal fungal blastospores in the renal tissues. Thus, in silico and histological data agreed with the findings in microbiology. Furthermore, within the CLSO treated group, a significant increase in the serum concentrations of creatinine was observed, while no significant difference in blood urea values was recorded after day 14 post-infection study. Linoleic and palmitic acid could be considered as a potential antifungal drug candidate with palmitic acid playing a significant role.

Demonstrated limitations in the mineral and nutritional composition of refined flours have led to calls for the possibility of enriching them with health-promoting supplements, such as high-value non-cereal seeds. Teff and watermelon seeds have been found suitable for the production of gluten-free flour, but so far, their potential to enrich conventional baking flours has not been comprehensively studied. Hence, the present study aimed at farinographic evaluation of dough based on refined wheat flour with additions of whole white teff (TF) and watermelon seed (WSF) and pomace (DWSF) flours (tested levels 10%, 20%, and 30%), as well as possibly extensive chemical characterization of the plant material tested, including LC-MS/MS, GC-MS, total phenolics, flavonoids, melatonin, and antioxidant potential. Most of the rheological traits were improved in the flour mixtures compared to the base white flour: development time and quality number (above 1.6-fold increase), softening and stability time (up to 1.3-fold change), and water absorption (up to 6%). Overall, the best results were achieved after the addition of watermelon seed pomace. The DWSF material was characterized by the highest levels of P, Mg, Na (7.5, 1.7, 0.4 g/kg, respectively), and Fe and Zn (124 and 27 mg/kg), while TF was the richest in Ca (0.9 g/kg) and Mn (43 mg/kg). Protein and fat levels were significantly higher in watermelon seeds compared to teff (about double and up to 10-fold, respectively). Phytochemical analyses highlighted the abundance of phenolics, especially flavones, in TF, WSF and DWSF flours (244, 93, and 721 mg/kg, respectively). However, the value of total polyphenols was low in all materials (

Soil salinization poses a huge challenge to the development of agriculture and seriously decreases crop yield and quality. In recent years, grafting has become one of the key agronomic techniques used to enhance plant abiotic stress tolerance. In this study, we found that watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] grafted onto bottle gourd (Lagenaria siceraria Standl.) significantly enhanced salt tolerance. Transcriptome analysis revealed that a total of 8462 differentially expressed genes (DEGs) were identified, and the number of up- and down-regulated genes were 3207 and 5255, respectively. The DEGs in the bottle gourd rootstock-grafted plants were mainly involved in carbon metabolism, photosynthesis, and plant hormone signal transduction. Furthermore, proteome analysis identified 28 differently expressed proteins (DEPs) in bottle gourd rootstock-grafted plants under salt stress. These DEPs were closely associated with amino acid and protein synthesis, photosynthesis, mitochondrial metabolism and carbon metabolism, and stress defense. Combined transcriptome and proteome analyses showed that salt stress-responded genes in bottle gourd rootstock-grafted watermelon seedlings were mainly involved in plant hormone signal transduction, photosynthesis, and amino acid synthesis pathways.

Background: Plant products, including seeds are an important source of vitamins, minerals, proteins, and energy. This study aimed to assess parasitic contaminations in roasted groundnuts, nabag, and tasali (watermelon seeds) sold by street vendors in Khartoum State, Sudan. Methods: The frequency of parasitic contaminations among all crop products was detected by washing the plants with saline, and then conducting an examination using a formal ether concentration technique (FECT), followed by a saturated sugar floatation technique. Results: The detected parasites belonged to two species: Entamoeba histolytica (33.3%) and Giardia lamblia (15.6%). No helminthic parasites were detected. Mixed contamination of the mentioned parasites was also observed (11.1%). The most contaminated crop was nabag, followed by groundnut, and finally tasali. Conclusion: No relation was established between the positivity of samples for parasites and crop type, Khartoum State city, or seller sex. FECT was more sensitive than the saturated sugar floatation technique as a detection method.