Post-harvest quality of melon accessions subjected to salinity.

The objective was to evaluate the behavior of melon genotypes (Cucumis melo L.) in the physical, chemical and biochemical quality of melon fruits as a function of electrical conductivity irrigation water levels (ECw). The experimental design adopted was randomized blocks in a 5 x 3 factorial scheme with five replications. The first factor was represented by five salinity levels (0.5, 1.5, 3.0, 4.5, and 6.0 dS m-1) and the second factor by accessions A35, and A24, and the hybrid Sancho. The physical, chemical and biochemical variables showed a reduction in production, with smaller fruits, with less weight, smaller cavity, with increased pulp thickness for Sancho. Vitamin C and yellow flavonoids increased indicating antioxidant power against ROS. The genotypes showed similar post-harvest behavior, however, the hybrid Sancho stood out over the others, possibly because it is an improved material. Accession A24 presented physiological and biochemical responses that classify it as intolerant.

Archaeobotanical evidence supports indigenous cucurbit long-term use in the Mesoamerican Neotropics.

The squash family (Cucurbitaceae) contains some of the most important crops cultivated worldwide and has played an important ecological, economic, and cultural role for millennia. In the American tropics, squashes were among the first cultivated crop species, but little is known about how their domestication unfolded. Here, we employ direct radiocarbon dating and morphological analyses of desiccated cucurbit seeds, rinds, and stems from El Gigante Rockshelter in Honduras to reconstruct human practices of selection and cultivation of Lagenaria siceraria, Cucurbita pepo, and Cucurbita moschata. Direct radiocarbon dating indicates that humans started using Lagenaria and wild Cucurbita starting ~ 10,950 calendar years before present (cal B.P.), primarily as watertight vessels and possibly as cooking and drinking containers. A rind directly dated to 11,150-10,765 cal B.P. represents the oldest known bottle gourd in the Americas. Domesticated C. moschata subsequently appeared ~ 4035 cal B.P., followed by domesticated C. pepo ~ 2190 cal B.P. associated with increasing evidence for their use as food crops. Multivariate statistical analysis of seed size and shape show that the archaeological C. pepo assemblage exhibits significant variability, representing at least three varieties: one similar to present-day zucchini, another like present-day vegetable marrow, and a native cultivar without modern analogs. Our archaeobotanical data supports the hypothesis that Indigenous cucurbit use started in the Early Holocene, and that agricultural complexity during the Late Holocene involved selective breeding that encouraged crop diversification.

Effects of refused melon fruit in Canarana grass ensilage on intake, digestibility, serum biochemistry, performance, carcass characteristics and meat attributes of feedlot lambs.

Ensilage of refused fruit with forage is a viable approach to increase resource use in ruminant feed. The objective of this study was to investigate the impact of ensiling refused melon fruit (RMF) with Canarana grass on the intake, apparent digestibility, serum biochemistry, performance, carcass traits, and meat attributes of feedlot lambs. Four distinct silage treatment types were prepared by ensiling RMF at 0 g/kg (control), 70 g/kg, 140 g/kg, and 210 g/kg (as fed) with Canarana grass. Twenty-eight male Santa Inês lambs (7 lambs per treatment), initially weighing 22.3 ± 1.0 kg at 120 days of age, were distributed in a completely randomized design and confined for a total of 96 days, including a 23-day adaptation period and 73 experimental days in a feedlot. The lambs received the treatment-silage in diets as a complete mixture with a roughage: concentrate ratio of 30:70. The inclusion of RMF in Canarana grass ensilage decreased (P < 0.05) the lambs' intake of dry matter, crude protein and metabolisable energy. The inclusion of RMF in ensilage had a quadratic effect (P < 0.05) on the digestibility of non-fibrous carbohydrates. The serum total protein and cholesterol levels decreased (P < 0.05) with the inclusion of RMF in the ensilage, but we observed no effect on the final weight and average daily gain of the lambs. The feed efficiency increased (P < 0.05) by including RMF in the Canarana grass ensilage. The RMF in the ensilage did not influence cold carcass weight and yield. The fat content of the meat decreased (P < 0.05) with the inclusion of RMF in the ensilage. It is recommended the inclusion of up to 210 g/kg of RMF in Canarana grass ensilage to increase feed efficiency and avoid impacts on the performance and carcass attributes of confined lambs.

Effect of defatted Lagenaria siceraria (Molina) Standley seed flour as a fat replacer on physicochemical, technological, and sensory properties of beef patty.

Defatted Lagenaria siceraria seed flour (DLSSF) was obtained from defatted seed cake, dried, and ground through a sieve of 500 µm and characterized. A 2 × 4 factorial design (two flour hydration rates and four fat substitution rates) was used to produce a low-fat beef patty by replacing fat with DLSSF. Beef kidney fat was used to formulate the control sample. Chemical, physical, technological, sensory, and nutritional characteristics of low-fat beef patties manufactured were evaluated. DLSSF contains mainly protein. As fat replacers, DLSSF induces a significant increase in the pH of the raw and cooked patty, the moisture and protein contents, the cooking yield, the cohesion, chewiness, springiness, and lightness of the cooked beef patty with fat substitution rate. There is a decrease in fat content, total calories, water retention capacity, hardness, and redness of the cooked patty with a fat substitution rate. From the sensory analysis, the substitution of fat improves the acceptability of samples. Based on the overall parameters analyzed, DLSSF containing 60% water can be used to produce low-fat beef patty by replacing fat at 100%. From these results, hydrated DLSSF could be an effective method to solve the problems of noncommunicable diseases related to animal fat consumption.

Recent advancements in mogrosides: A review on biological activities, synthetic biology, and applications in the food industry.

Mogrosides are low-calorie, biologically active sweeteners that face high production costs due to strict cultivation requirements and the low yield of monk fruit. The rapid advancement in synthetic biology holds the potential to overcome this challenge. This review presents mogrosides exhibiting antioxidant, anti-inflammatory, anti-cancer, anti-diabetic, and liver protective activities, with their efficacy in diabetes treatment surpassing that of Xiaoke pills (a Chinese diabetes medication). It also discusses the latest elucidated biosynthesis pathways of mogrosides, highlighting the challenges and research gaps in this field. The critical and most challenging step in this pathway is the transformation of mogrol into a variety of mogrosides by different UDP-glucosyltransferases (UGTs), primarily hindered by the poor substrate selectivity, product specificity, and low catalytic efficiency of current UGTs. Finally, the applications of mogrosides in the current food industry and the challenges they face are discussed.

A nonsynonymous mutation in BhLS, encoding an acyl-CoA N-acyltransferase leads to fruit and seed size variation in wax gourd (Benincasa hispida).

Wax gourd (Benincasa hispida (Thunb.) Cogn., 2n = 2x = 24) is an economically important vegetable crop cultivated widely in many tropical and subtropical regions, including China, India, and Japan. Both fruit and seeds are prized agronomic attributes in wax gourd breeding and production. However, the genetic mechanisms underlying these traits remain largely unexplored. In this study, we observed a strong correlation between fruit size and seed size variation in our mapping population, indicating genetic control by a single gene, BhLS, with large size being dominant over small. Through bulk segregant analysis sequencing and fine mapping with a large F2 population, we precisely located the BhLS gene within a 47.098-kb physical interval on Chromosome 10. Within this interval, only one gene, Bhi10M000649, was identified, showing homology to Arabidopsis HOOKLESS1. A nonsynonymous mutation (G to C) in the second exon of Bhi10M000649 was found to be significantly associated with both fruit and seed size variation in wax gourd. These findings collectively highlight the pleiotropic effect of the BhLS gene in regulating fruit and seed size in wax gourd. Our results offer molecular insights into the variation of fruit and seed size in wax gourd and establish a fundamental framework for breeding wax gourd cultivars with desired traits.

Sequence characteristics, genetic diversity and phylogenetic analysis of the Cucurbita ficifolia (Cucurbitaceae) chloroplasts genome.

BACKGROUND: Curcubita ficifolia Bouché (Cucurbitaceae) has high value as a food crop and medicinal plant, and also has horticultural value as rootstock for other melon species. China is home to many different cultivars, but the genetic diversity of these resources and the evolutionary relationships among them, as well as the differences between C. ficifolia and other Cucurbita species, remain unclear. RESULTS: We investigated the chloroplast (cp) genomes of 160 C. ficifolia individuals from 31 populations in Yunnan, a major C. ficifolia production area in China. We found that the cp genome of C. ficifolia is ~151 kb and contains 128 genes, of which 86 are protein coding genes, 34 encode tRNA, and eight encode rRNAs. We also identified 64 SSRs, mainly AT repeats. The cp genome was found to contain a total of 204 SNP and 57 indels, and a total of 21 haplotypes were found in the 160 study individuals. The reverse repeat (IR) region of C. ficifolia contained a few differences compared with this region in the six other Cucurbita species. Sequence difference analysis demonstrated that most of the variable regions were concentrated in the single copy (SC) region. Moreover, the sequences of the coding regions were found to be more similar among species than those of the non-coding regions. The phylogenies reconstructed from the cp genomes of 61 representative species of Cucurbitaceae reflected the currently accepted classification, in which C. ficifolia is sister to the other Cucurbita species, however, different interspecific relationships were found between Cucurbita species. CONCLUSIONS: These results will be valuable in the classification of C. ficifolia genetic resources and will contribute to our understanding of evolutionary relationships within the genus Cucurbita.

Bacterial diversity and composition on the rinds of specific melon cultivars and hybrids from across different growing regions in the United States.

The goal of this study was to characterize the bacterial diversity on different melon varieties grown in different regions of the US, and determine the influence that region, rind netting, and variety of melon has on the composition of the melon microbiome. Assessing the bacterial diversity of the microbiome on the melon rind can identify antagonistic and protagonistic bacteria for foodborne pathogens and spoilage organisms to improve melon safety, prolong shelf-life, and/or improve overall plant health. Bacterial community composition of melons (n = 603) grown in seven locations over a four-year period were used for 16S rRNA gene amplicon sequencing and analysis to identify bacterial diversity and constituents. Statistically significant differences in alpha diversity based on the rind netting and growing region (p < 0.01) were found among the melon samples. Principal Coordinate Analysis based on the Bray-Curtis dissimilarity distance matrix found that the melon bacterial communities clustered more by region rather than melon variety (R2 value: 0.09 & R2 value: 0.02 respectively). Taxonomic profiling among the growing regions found Enterobacteriaceae, Bacillaceae, Microbacteriaceae, and Pseudomonadaceae present on the different melon rinds at an abundance of ≥ 0.1%, but no specific core microbiome was found for netted melons. However, a core of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae were found for non-netted melons. The results of this study indicate that bacterial diversity is driven more by the region that the melons were grown in compared to rind netting or melon type. Establishing the foundation for regional differences could improve melon safety, shelf-life, and quality as well as the consumers' health.

A Flavonoid Glycoside Compound from Siraitia grosvenorii with Anti-Inflammatory and Hepatoprotective Effects In Vitro.

Inflammation is a pivotal factor in the development and advancement of conditions like NAFLD and asthma. Diet can affect several phases of inflammation and significantly influence multiple inflammatory disorders. Siraitia grosvenorii, a traditional Chinese edible and medicinal plant, is considered beneficial to health. Flavonoids can suppress inflammatory cytokines, which play a crucial role in regulating inflammation. In the present experiments, kaempferol 3-O-α-L-rhamnoside-7-O-ß-D-xylosyl(1→2)-O-α-L-rhamnoside (SGPF) is a flavonoid glycoside that was first isolated from S. grosvenorii. A series of experimental investigations were carried out to investigate whether the flavonoid component has anti-inflammatory and hepatoprotective effects in this plant. The researchers showed that SGPF has a stronger modulation of protein expression in LPS-induced macrophages (MH-S) and OA-induced HepG2 cells. The drug was dose-dependent on cells, and in the TLR4/NF-κB/MyD88 pathway and Nrf2/HO-1 pathway, SGPF regulated all protein expression. SGPF has a clear anti-inflammatory and hepatoprotective function in inflammatory conditions.

Genome-Wide Analysis of the LBD Gene Family in Melon and Expression Analysis in Response to Wilt Disease Infection.

LBD transcription factors are a class of transcription factors that regulate the formation of lateral organs, establish boundaries, and control secondary metabolism in plants. In this study, we identified 37 melon LBD transcription factors using bioinformatics methods and analyzed their basic information, chromosomal location, collinearity, evolutionary tree, gene structure, and expression patterns. The results showed that the genes were unevenly distributed across the 13 chromosomes of melon plants, with tandem repeats appearing on chromosomes 11 and 12. These 37 transcription factors can be divided into two major categories, Class I and Class II, and seven subfamilies: Ia, Ib, Ic, Id, Ie, IIa, and IIb. Of the 37 included transcription factors, 25 genes each contained between one to three introns, while the other 12 genes did not contain introns. Through cis-acting element analysis, we identified response elements such as salicylic acid, MeJA, abscisic acid, and auxin, gibberellic acid, as well as light response, stress response, and MYB-specific binding sites. Expression pattern analysis showed that genes in the IIb subfamilies play important roles in the growth and development of various organs in melon plants. Expression analysis found that the majority of melon LBD genes were significantly upregulated after infection with wilt disease, with the strongest response observed in the stem.

Transcriptomic analysis provides an insight into the function of CmGH9B3, a key gene of ß-1, 4-glucanase, during the graft union healing of oriental melon scion grafted onto squash rootstock.

The melon (Cucumis melo L.) is a globally cherished and economically significant crop. The grafting technique has been widely used in the vegetative propagation of melon to promote environmental tolerance and disease resistance. However, mechanisms governing graft healing and potential incompatibilities in melons following the grafting process remain unknown. To uncover the molecular mechanism of healing of grafted melon seedlings, melon wild type (Control) and TRV-CmGH9B3 lines were obtained and grafted onto the squash rootstocks (C. moschata). Anatomical differences indicated that the healing process of the TRV-CmGH9B3 plants was slower than that of the control. A total of 335 significantly differentially expressed genes (DEGs) were detected between two transcriptomes. Most of these DEGs were down-regulated in TRV-CmGH9B3 grafted seedlings. GO and KEGG analysis showed that many metabolic, physiological, and hormonal responses were involved in graft healing, including metabolic processes, plant hormone signaling, plant MAPK pathway, and sucrose starch pathway. During the healing process of TRV-CmGH9B3 grafted seedlings, gene synthesis related to hormone signal transduction (auxin, cytokinin, gibberellin, brassinolide) was delayed. At the same time, it was found that most of the DEGs related to the sucrose pathway were down-regulated in TRV-CmGH9B3 grafted seedlings. The results showed that sugar was also involved in the healing process of melon grafted onto squash. These results deepened our understanding of the molecular mechanism of GH9B3, a key gene of ß-1, 4-glucanase. It also provided a reference for elucidating the gene mechanism and function analysis of CmGH9B3 in the process of graft union healing.

Integrative analysis of the metabolome and transcriptome provides insights into the mechanisms of lignan biosynthesis in Herpetospermum pedunculosum (Cucurbitaceae).

BACKGROUND: Herpetospermum pedunculosum (Ser.) C. B. Clarke is a traditional Chinese herbal medicine that heavily relies on the lignans found in its dried ripe seeds (Herpetospermum caudigerum), which have antioxidant and hepatoprotective functions. However, little is known regarding the lignan biosynthesis in H. pedunculosum. In this study, we used metabolomic (non-targeted UHPLC-MS/MS) and transcriptome (RNA-Seq) analyses to identify key metabolites and genes (both structural and regulatory) associated with lignan production during the green mature (GM) and yellow mature (YM) stages of H. pedunculosum. RESULTS: The contents of 26 lignan-related metabolites and the expression of 30 genes involved in the lignan pathway differed considerably between the GM and YM stages; most of them were more highly expressed in YM than in GM. UPLC-Q-TOF/MS confirmed that three Herpetospermum-specific lignans (including herpetrione, herpetotriol, and herpetin) were found in YM, but were not detected in GM. In addition, we proposed a lignan biosynthesis pathway for H. pedunculosum based on the fundamental principles of chemistry and biosynthesis. An integrated study of the transcriptome and metabolome identified several transcription factors, including HpGAF1, HpHSFB3, and HpWOX1, that were highly correlated with the metabolism of lignan compounds during seed ripening. Furthermore, functional validation assays revealed that the enzyme 4-Coumarate: CoA ligase (4CL) catalyzes the synthesis of hydroxycinnamate CoA esters. CONCLUSION: These results will deepen our understanding of seed lignan biosynthesis and establish a theoretical basis for molecular breeding of H. pedunculosum.

Antihyperglycemic and antihyperlipidemic effects of fruit extract of Hodgsonia heteroclita (Roxb.) Hook. f. & Thomson in diabetic mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Hodgsonia heteroclita has been known as an important traditionally consumed medicinal plant of North-East India known to have antidiabetic properties. This study aims to investigate the effects of the ethanolic fruit extract of Hodgsonia heteroclita against hyperglycemia and hyperlipidemia by using streptozotocin (STZ) treated diabetic mice. MATERIALS AND METHODS: The fruits of H. heteroclita were collected from the various parts of Kokrajhar district, Assam India (Geographic coordinates: 26°24'3.85″ N 90°16'22.30″ E). Basic morphological evaluations were carried out by the Botanical Survey of India, Eastern circle, Shillong, who also certified and identified the plant. Hexane, chloroform, and ethanolic extracts of the fruit of H. heteroclita were investigated for α-amylase inhibition assay as a rapid screening tool for examining anti-diabetic activity. The efficacy of ethanolic extract at a dose of 100, 200, and 300 mg/kg body weight was tested for 21 days in STZ-induced diabetic mice. The body weight, fasting plasma glucose and serum lipids, and hepatic glycogen levels were measured in experimental animals to examine the antihyperglycemic and antihyperlipidemic efficacy of the extract. Both HPTLC and LC-MS analysis was performed to examine the phyotochemicals present in the ethanolic extract of H. heteroclita. RESULTS: It has been observed that treatment with the ethanolic extract dose-dependently reduced the plasma glucose levels, total cholesterol, low density lipoprotein-cholesterol, very low-density lipoprotein-cholesterol, triglyceride, and increased the body weight, liver glycogens and high-density lipoprotein-cholesterol in STZ treated diabetic mice. HPTLC demonstrated the presence of triterpene compounds and LC-MS analysis revealed the presence Cucurbitacin I, Cucurbitacin E, and Kuguacin G as the triterpene phytoconstituents. CONCLUSION: The present study demonstrated that ethanolic fruit extract of H. heteroclita improved both glycemic and lipid parameters in mice model of diabetes.

Rice husk ash based growing media impact on cucumber and melon growth and quality.

Rice husk, an agricultural waste from the rice industry, can cause serious environmental pollution if not properly managed. However, rice husk ash (RHA) has been found to have many positive properties, making it a potential replacement for non-renewable peat in soilless planting. Thus, this study investigated the impact of a RHA composite substrate on the growth, photosynthetic parameters, and fruit quality of cucumber (Yuyi longxiang variety) and melon (Yutian yangjiaomi variety). The RHA, peat, vermiculite, and perlite were blended in varying proportions, with the conventional seedling substrate (peat:vermiculite:perlite = 1:1:1 volume ratio) serving as the control (CK). All plants were cultivated in barrels filled with 10L of the mixed substrates. The results from this study found that RHA 40 (RHA:peat:vermiculite:perlite = 4:4:1:1 volume ratio) significantly enhanced substrate ventilation and positively influenced the stem diameter, root activity, seedling index, chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of cucumber and melon plants. Additionally, plant planted using RHA 40, the individual fruit weight of cucumber and melon found to increase by 34.62% and 21.67%, respectively, as compared to the control. Aside from that, both cucumber and melon fruits had significantly higher sucrose, total soluble sugar, vitamin C, and soluble protein levels. This subsequently improved the activity of sucrose synthase and sucrose phosphate synthase in both cucumber and melon. In conclusion, the RHA 40 found to best promote cucumber and melon plant growth, increase plant leaf photosynthesis, and improve cucumber and melon fruit quality, making it a suitable substrate formula for cucumber and melon cultivation in place of peat.

Siraitia grosvenorii As a Homologue of Food and Medicine: A Review of Biological Activity, Mechanisms of Action, Synthetic Biology, and Applications in Future Food.

Siraitia grosvenorii (SG), also known as Luo Han Guo or Monk fruit, boasts a significant history in food and medicine. This review delves into SG's historical role and varied applications in traditional Chinese culture, examining its phytochemical composition and the health benefits of its bioactive compounds. It further explores SG's biological activities, including antioxidant, anti-inflammatory, and antidiabetic properties and elucidates the mechanisms behind these effects. The review also highlights recent synthetic biology advances in enhancing the production of SG's bioactive compounds, presenting new opportunities for broadening their availability. Ultimately, this review emphasizes SG's value in food and medicine, showcasing its historical and cultural importance, phytochemistry, biological functions, action mechanisms, and the role of synthetic biology in its sustainable use.

A review on the traditional uses, nutritive importance, pharmacognostic features, phytochemicals, and pharmacology of Momordica cymbalaria Hook F.

Momordica cymbalaria Hook F. (MC), belonging to the family Cucurbitaceae, is a plant with several biological activities. This detailed, comprehensive review gathers and presents all the information related to the geographical distribution, morphology, therapeutic uses, nutritional values, pharmacognostic characters, phytochemicals, and pharmacological activities of MC. The available literature showed that MC fruits are utilized as a stimulant, tonic, laxative, stomachic, and to combat inflammatory disorders. The fruits are used to treat spleen and liver diseases and are applied in folk medicine to induce abortion and treat diabetes mellitus. The phytochemical screening studies report that MC fruits contain tannins, alkaloids, phenols, proteins, amino acids, vitamin C, carbohydrates, ß-carotenes, palmitic acid, oleic acid, stearic acid, α-eleostearic acid, and γ-linolenic acid. The fruits also contain calcium, sodium, iron, potassium, copper, manganese, zinc, and phosphorus. Notably, momordicosides are cucurbitacin triterpenoids reported in the fruits of MC. Diverse pharmacological activities of MC, such as analgesic, anti-inflammatory, antioxidant, hepatoprotective, nephroprotective, antidiabetic, cardioprotective, antidepressant, anticonvulsant, anticancer, antiangiogenic, antifertility, antiulcer, antimicrobial, antidiarrheal and anthelmintic, have been reported by many investigators. M. cymbalaria methanolic extract is safe up to 2,000 mg/kg. Furthermore, no symptoms of toxicity were found. These pharmacological activities are mechanistically interpreted and described in this review. Additionally, the microscopic, powder and physiochemical characteristics of MC tubers are also highlighted. In summary, possesses remarkable medicinal values, which warrant further detailed studies to exploit its potential benefits therapeutically.

Biocontrol of Escherichia coli O157:H7 by Enterobacter asburiae AEB30 on intact cantaloupe melons.

Escherichia coli O157:H7 causes >73,000 foodborne illnesses in the United States annually, many of which have been associated with fresh ready-to-eat produce including cantaloupe melons. In this study, we created a produce-associated bacterial (PAB) library containing >7500 isolates and screened them for the ability to inhibit the growth of E. coli O157:H7 using an in vitro fluorescence-based growth assay. One isolate, identified by 16S and whole-genome sequence analysis as Enterobacter asburiae, was able to inhibit the growth of E. coli by ~30-fold in vitro and produced zones of inhibition between 13 and 21 mm against 12 E. coli outbreak strains in an agar spot assay. We demonstrated that E. asburiae AEB30 was able to grow, persist and inhibit the growth of E. coli on cantaloupe melons under simulated pre- and post-harvest conditions. Analysis of the E. asburiae AEB30 genome revealed an operon encoding a contact-dependent growth inhibition (CDI) system that when mutated resulted in the loss of E. coli growth inhibition. These data suggest that E. asburiae AEB30 is a potential biocontrol agent to prevent E. coli contamination of cantaloupe melons in both pre- and post-harvest environments and that its mode of action is via a CDI system.

Genomic and pangenomic analyses provide insights into the population history and genomic diversification of bottle gourd.

Bottle gourd (Lagenaria siceraria (Mol.) Strandl.) is an economically important vegetable crop and one of the earliest domesticated crops. However, the population history and genomic diversification of bottle gourd have not been extensively studied. We generated a comprehensive bottle gourd genome variation map from genome sequences of 197 world-wide representative accessions, which enables a genome-wide association study for identifying genomic loci associated with resistance to zucchini yellow mosaic virus, and constructed a bottle gourd pangenome that harbors 1534 protein-coding genes absent in the reference genome. Demographic analyses uncover that domesticated bottle gourd originated in Southern Africa c. 12 000 yr ago, and subsequently radiated to the New World via the Atlantic drift and to Eurasia through the efforts of early farmers in the initial Holocene. The identified highly differentiated genomic regions among different bottle gourd populations harbor many genes contributing to their local adaptations such as those related to disease resistance and stress tolerance. Presence/absence variation analysis of genes in the pangenome reveals numerous genes including those involved in abiotic/biotic stress responses that have been under selection during the world-wide expansion of bottle gourds. The bottle gourd variation map and pangenome provide valuable resources for future functional studies and genomics-assisted breeding.

Integrated full-length transcriptome and metabolome analysis reveals the defence response of melon to gummy stem blight.

Gummy stem blight (GSB), a widespread disease causing great loss to cucurbit production, has become a major threat to melon cultivation. However, the melon-GSB interaction remains largely unknown. Here, full-length transcriptome and widely targeted metabolome were used to investigate the defence responses of resistant (PI511089) and susceptible (Payzawat) melon accessions to GSB pathogen infection at 24 h. The biosynthesis of secondary metabolites and MAPK signalling pathway were specifically enriched for differentially expressed genes in PI511890, while carbohydrate metabolism and amino acid metabolism were specifically enriched in Payzawat. More than 1000 novel genes were identified and MAPK signalling pathway was specifically enriched for them in PI511890. There were 11 793 alternative splicing events involving in the defence response to GSB. Totally, 910 metabolites were identified in Payzawat and PI511890, and flavonoids were the dominant metabolites. Integrated full-length transcriptome and metabolome analysis showed eriodictyol and oxalic acid were the potential marker metabolites for GSB resistance in melon. Moreover, posttranscription regulation was widely involved in the defence response of melon to GSB pathogen infection. These results not only improve our understanding on the interaction between melon and GSB, but also facilitate the genetic improvement of melon with GSB resistance.

Sustainable cultivation of melon landraces: Effects of grafting on the accumulation of flavor-related compounds.

Melon landraces are highly appreciated by consumers who pay price premiums to compensate for lower yields, enabling on-farm conservation. However, they are highly susceptible to soilborne diseases. This study analyses the impact of Cucurbita and Cucumis rootstocks on the accumulation of flavor-related metabolites in Spanish landraces of the Ibericus melon group, as a strategy to promote their sustainable cultivation. Scion genotype was the main factor conditioning the accumulation of sugars and acids both under standard and saline organic farming conditions. The effects of grafting on organic acid accumulation were negligible, while the effects on sugar content were significant. The latter effects were dependent on specific scion-rootstock combinations, though wild Cucumis (e.g. Fian) rootstocks represent an alternative that should be further studied. The effect on the accumulation of volatiles was limited, and again depended on specific scion-rootstock combinations. The rootstock effect even differed between populations of the same landrace.