Polyploid seeds production is laborious, complicated, and costly work. Tetraploid and triploid plants produce a fewer number of seeds/fruit, and triploid embryos are fairly weak, covered with a more hardened seed coat as compared to diploid seeds. Here we investigated the interactive effect of new grafting technique of polyploid watermelon scion onto rootstock on plants' survival rate, biochemical, and hormones contents. In this study, three different branches, apical meristem (AM), branch with 1 node (1N), and 2 nodes (2N) from di, Tri, and tetraploid watermelon plants, were used as scion and grafted onto squash rootstock. The results showed highly significant differences between polypoid watermelon when 1N using as a scion, tetraploid showed maximum survival rates, higher contents of hormones, and antioxidants (AOX) activities, compared to diploid, these may be the possible reasons for high compatibility in tetraploid and degrading the grafting zone in diploid. RTq-PCR results confirm that the expression of genes linked to compatibility is consistent with the hormonal and AOX activities. This study provides an alternative and economical approach to produce more tetraploid and triploid plants for breeding or seeds production by using branches as scions.

Polyploid seed production is complicated, and costly work, produce a fewer number of seeds/fruits as compared to diploid seeds. Here we investigated the interactive effect of a new grafting technique of polyploid watermelon scion onto rootstock on plants' survival rate. In this study, three different branches, apical meristem (AM), branch with 1 node (1N), and 2 nodes (2N) from di, tri, and tetraploid watermelon plants, were used as scion and grafted onto squash rootstock. The results showed highly significant differences between polypoid watermelon when 1N was used as a scion. Tetraploid showed maximum survival rates, higher contents of hormones, carbohydrates, and antioxidants activities, compared to diploid. Here, we also performed applied sucrose exogenously, on the rootstocks seedlings before grafting to enhance survival rates. Significant survival rates were observed in the case of 2% sucrose application in all polyploids when 1N was used as a scion. RTq-PCR results confirm that the expression of genes linked to compatibility is consistent with the carbohydrates, hormonal and antioxidants activities. This study provides an alternative and economical approach to produce more tetraploid and triploid plants for breeding and seed production by using branches as scions, furthermore, provides more understanding of graft compatibility.

Watermelon fruits of different ploidy exhibit significant variations in texture. In order to investigate the primary factors influencing texture differences, this study was conducted to investigate the differences in fruit texture development using homozygous autogamous diploid (2X)lines and their autotriploid (3X) and autotetraploid (4X) lines 'Yixuan'. The research encompassed fruit development, flesh texture profile analysis (TPA), flesh cell wall polysaccharide content, and flesh cell microstructure analysis, specifically in 2X, 3X, and 4X watermelon fruits.The results showed that as watermelon fruits matured, several characteristics exhibited an ascending trend, including fruit weight, TSS (total soluble solids) content, rind hardness, flesh cell size, and cell wall polysaccharide contents such as crude fiber, cellulose, hemicellulose, lignin, and protopectin. Conversely, the flesh texture parameters and soluble pectin content of the flesh cell wall gradually declined. Notably, significant differences in fruit flesh texture and flesh cell structure were observed among fruits of different ploidy at the 32d. Specifically, 2X fruits displayed considerably lower rind hardness, reduced flesh texture (Hardness, Fracturability, Chewiness, Gumminess), and cell density compared to 3X and 4X fruits. Additionally, 2X fruits exhibited larger cell sizes than 3X and 4X fruits. However, no significant differences were observed in the content of flesh cell wall polysaccharide contents across various ploidy levels.These findings suggested that the variation in texture among watermelon fruits of different ploidy can be attributed to the size and arrangement of flesh cells. Importantly, this research provided a foundation for further exploration of the intrinsic regulatory factors and molecular mechanisms contributing to texture variation in polyploid watermelon fruits.

Damping-off caused by Pythium aphanidermatum (Pa) is one of the most destructive diseases for watemelon seedlings. Application of biological control agents against Pa has attracted attention of many researchers for a long time. In this study, an actinomycete isolate JKTJ-3 with strong and broad-spectrum antifungal effect was screened from 23 bacterial isolates. Based on the morphological, cultural, physiological, and biochemical characteristics as well as the feature of 16S rDNA sequence, isolate JKTJ-3 was identified as Streptomyces murinus. We compared the biocontrol efficacy of isolate JKTJ-3 and its metabolites. The results revealed that seed and substrate treatments with the JKTJ-3 cultures showed a significant inhibitory effect on watermelon damping-off disease. Seed treatment with the JKTJ-3 cultural filtrates (CF) had higher control efficacy that of the fermentation cultures (FC). Treatment of the seeding substrate with the wheat grain cultures (WGC) of JKTJ-3 exhibited better control efficacy than that of the seeding substrate with the JKTJ-3 CF. Moreover, the JKTJ-3 WGC showed the preventive effect on suppression of the disease, and the efficacy increased with increase in the inoculation interval between the WGC and Pa. Production of the antifungal metabolite actinomycin D by isolate JKTJ-3 and cell wall-degrading enzymmes such as β-1,3-glucanase and chitosanase was probably the mechanisms for effective control of watermelon damping-off. It was showed for the first time that S. murinus can produce anti-oomycete substances including chitinase and actinomycin D. This is the first report about S. murinus used as biocontrol agent against watermelon Pa-induced damping-off.

The soil-borne pathogens, particularly Fusarium oxysporum f. sp. niveum (FON) and southern root-knot nematode (RKN, Meloidogyne incognita) are the major threat to watermelon production in the south-eastern United States. The role of soil micronutrients on induced resistance (IR) to plant diseases is well-documented in soil-based mediums. However, soil-based mediums limit the determination of the role(s) of individual micronutrients in IR. In this manuscript, we utilized hydroponics to assess the effect of controlled application of micronutrient, including iron (Fe), manganese (Mn), and zinc (Zn) on the expression of some IR genes (PR1, PR5, and NPR1 from salicylic acid (SA) pathway, and VSP, PDF, and LOX genes from jasmonic acid (JA) pathway) in watermelon seedlings upon inoculation with either FON or RKN or both. Plants were treated with higher (3X) or lower (0.5X) concentrations of micronutrients in Steiner solution (X= standard dose of micronutrient) for 7 days in a hydroponics system under greenhouse conditions. A subset of micronutrient-treated plants was inoculated (on the 8th day of micronutrient application) with FON and RKN (single and mixed). The expression of the IR genes in treated and control samples were evaluated using qRT-PCR. Although, significant phenotypic differences were not observed with respect to the severity of wilt symptoms or RKN galling with any of the micro-nutrient treatments within the 30 day-experimental-period, differences in the induction of IR genes were observed. However, the level of gene expression varied with sampling period, type and concentration of micro-nutrients ap-plied, and pathogen-inoculation. In the absence of pathogens, no significant changes were observed in the expression level of IR genes on 7th day of micronutrient treatment. However, pathogen inoculation affected the expression levels of the IR genes at 3-day post-inoculation. In FON inoculated plants, PDF was upregulated in high Fe treatment, whereas in RKN inoculated plants, low Mn treatment resulted in up-regulation of VSP. In the case of mixed inoculation with FON and RKN, the plants with low Zn treatment resulted in the upregulation of PR1. These observations suggest that the type and concentration of micronutrients in watermelon may potentially induce systemic resistance against FON and RKN through SA and JA pathways.

Drought-tolerant plants have become a convenient model to study the mechanisms underlying drought tolerance to improve the susceptible domesticated relatives. Various studies have shown that wild watermelon possess superior qualities that aid its survival in harsh environmental conditions. One of the key mechanisms that aids the tolerance of the crop has been noted as its timely stomatal regulation. In this study, the physiological, morphological and molecular stomatal responses of a drought-tolerant (wild watermelon) and four other watermelons genotypes were evaluated under drought stress. The watermelon plants were grown under water deficit (complete withholding of watering) and non-stress treatment. The highest SPAD values were recorded in wild and cooking (50 ± 3) watermelon genotypes and Crimson sweet (27 ± 0.37) had the lowest SPAD values showing the ability of the tolerant genotypes to maintain their system during drought stress. Fluorescence parameters also gave an important clue into the tolerant genotypes with cooking and wild watermelon under drought stress while the domesticated genotypes showed slow response to fluorescence parameters, something that might lead to damage to photosynthesis apparatus. Stomatal opening during drought showed that the wild watermelon limited its opening with the progress of drought as at day 9 it had the lowest opening of 23.1 ± 1.2 µm as compared to other genotypes and most importantly upon re-watering it showed rapid recovery than all the genotypes. And these was also expressed in mRNA quantification of stomatal aperture TFs where wild watermelon recorded 8 fold increase on stomatal closure CLROC3 TFs. And all these mechanisms have been attributed to the tolerance mechanisms of the drought tolerant watermelon genotypes.

Cancer researchers are fascinated by the chemistry of diverse natural products which show exciting potential as anticancer agents. In this study, we aimed to investigate the anticancer properties of watermelon rind extract (WRE) by examining its effects on cell proliferation, apoptosis, senescence, and global gene expression in human renal cell adenocarcinoma cells (HRAC-769-P) in vitro. Our metabolome data analysis of WRE exhibited untargeted phyto-constituents and targeted citrulline (22.29 µg/mg). HRAC-769-P cells were cultured in RPMI-1640 media and treated with 22.4, 44.8, 67.2, 88.6, 112, 134.4, and 156.8 mg mL-1 for 24, 48, and 72 hrs. At 24 hrs after treatment, (88.6 mg ml-1 of WRE) cell proliferation significantly reduced, more than 34% compared to the control. Cell viability decreased 48 and 72 hours after treatment to 45% and 37%, respectively. We also examined poly caspase, SA-beta-galactosidase (SA-beta-gal), and wound healing activities using WRE. All treatments induced an early poly caspase response and a significant reduction in cell migration. Further, we analyzed the transcript profile of the cells grown at 44.8 mg ml-1 of WRE after 6 hours using RNA sequencing (RNAseq) analysis. We identified 186 differentially expressed genes (DEGs), including 149 upregulated genes and 37 downregulated genes, in cells treated with WRE compared to the control. The differentially expressed genes were associated with NF-Kappa B signaling and TNF pathways. Crucial apoptosis-related genes such as BMF, NPTX1, NFKBIA, NFKBIE, and NFKBID might induce intrinsic and extrinsic apoptosis. Another possible mechanism is a high quantity of citrulline may lead to induction of apoptosis by the production of increased nitric oxide. Hence, our study suggests the potential anticancer properties of WRE and provides insights into its effects on cellular processes and gene expression in HRAC-769-P cells.

{Background}: to develop a technology for hydrothermal processing of oilseeds and primary pressed cake in order to obtain functional vegetable oils from non-traditional oilseeds (melon and watermelon seeds). {Methods:} Analyses of mint, pulp, oils and cakes obtained from them were carried out in accordance with the methodology described in the "Manual on research Methods, technochemical control and accounting of production in the fat and oil industry". {Results:} Technological parameters of hydrothermal treatment of crushed oilseeds from melon and watermelon seeds before primary and final pressing are investigated. {Conclusions:} An advanced double pressing technology has been developed, which provides grinding of seeds without separating the husk up to 60% when passing through a sieve with a diameter of 1 mm, humidification with steam condensate up to 11% and heat treatment at a temperature of 80℃ for 50 minutes before pre-pressing and grinding up to 60% of the patency of the pre-pressed cake, moistening the material to a humidity of 12% steam at a temperature of 120 ° C and a pressure of 0.5 MPa for 30 minutes before distillation.

The increasing demand by consumers for popular healthy fruits, such as the watermelon (Citrullus lanatus), generate substantial bio-wastes, making it imperative to harness the value of these by-products. Watermelon has low-calorie content and several other nutritional benefits that make it suitable for weight management and heart-healthy diets. Within this article, the nutritional composition and bioactives of watermelon which are strongly linked to the prevention of cardiovascular disorders (CVD), cancer, and age-related conditions, will be thoroughly reviewed. In addition, the therapeutic potential effects of watermelon consumption, such as anti-inflammatory, cardio-protective and anti-cancer properties, are also examined, with emphasis to the importance of incorporating watermelon into regular diets for overall health improvement. Additionally, the study explores various applications of watermelon by-products in functional foods, contributing to meeting recommended daily nutrient allowances, as well as in other functional products like cosmetics, with health promoting properties. In conclusion, this comprehensive review underscores the role of watermelon and its by-products for the development of products that can contribute to the prevention of chronic diseases and promote overall well-being