Occurrence of Macrophomina phaseolina in Israel: Challenges for Disease Management and Crop Germplasm Enhancement.

Macrophomina phaseolina is a soil-borne fungal pathogen infecting many important crop plants. The fungus, which can survive on crop debris for a long period of time, causes charcoal rot disease by secreting a diverse array of cell-wall degrading enzymes and toxins. M. phaseolina thrives during periods of high temperatures and arid conditions, as typically occur in Israel and other countries with a Mediterranean climate. Crop losses due to charcoal rot can be expected to increase and spread to other countries in a warming global climate. Management of this pathogen is challenging, requiring an array of approaches for the various crop hosts. Approaches that have had some success in Israel include grafting of melons and watermelons on resistant squash rootstocks and soil application of fungicide to reduce disease incidence in melons, fumigation and alterations in planting date and mulching of strawberries, and alteration in irrigation regime of cotton. Elsewhere, these approaches, as well as soil amendments and addition of organisms that are antagonistic to M. phaseolina, have had success in some crop situations. Management through host resistance would be the most sustainable approach, but it requires identifying a resistant germplasm for each crop and introgressing the resistance into the leading cultivars. Resistance to charcoal rot is under complex genetic control in most crops, posing a great challenge for its introgression into elite germplasm. Moreover, fast, reliable methods of screening for resistance would have to be developed for each crop. The toothpick-inoculation method used by us holds great promise for selecting resistant germplasm for melons and possibly for sesame, but other methodologies have to be devised for each individual crop.

A comprehensive RNA-Seq-based gene expression atlas of the summer squash (Cucurbita pepo) provides insights into fruit morphology and ripening mechanisms.

BACKGROUND: Summer squash (Cucurbita pepo: Cucurbitaceae) are a popular horticultural crop for which there is insufficient genomic and transcriptomic information. Gene expression atlases are crucial for the identification of genes expressed in different tissues at various plant developmental stages. Here, we present the first comprehensive gene expression atlas for a summer squash cultivar, including transcripts obtained from seeds, shoots, leaf stem, young and developed leaves, male and female flowers, fruits of seven developmental stages, as well as primary and lateral roots. RESULTS: In total, 27,868 genes and 2352 novel transcripts were annotated from these 16 tissues, with over 18,000 genes common to all tissue groups. Of these, 3812 were identified as housekeeping genes, half of which assigned to known gene ontologies. Flowers, seeds, and young fruits had the largest number of specific genes, whilst intermediate-age fruits the fewest. There also were genes that were differentially expressed in the various tissues, the male flower being the tissue with the most differentially expressed genes in pair-wise comparisons with the remaining tissues, and the leaf stem the least. The largest expression change during fruit development was early on, from female flower to fruit two days after pollination. A weighted correlation network analysis performed on the global gene expression dataset assigned 25,413 genes to 24 coexpression groups, and some of these groups exhibited strong tissue specificity. CONCLUSIONS: These findings enrich our understanding about the transcriptomic events associated with summer squash development and ripening. This comprehensive gene expression atlas is expected not only to provide a global view of gene expression patterns in all major tissues in C. pepo but to also serve as a valuable resource for functional genomics and gene discovery in Cucurbitaceae.

The biosynthetic pathway of the nonsugar, high-intensity sweetener mogroside V from Siraitia grosvenorii.

The consumption of sweeteners, natural as well as synthetic sugars, is implicated in an array of modern-day health problems. Therefore, natural nonsugar sweeteners are of increasing interest. We identify here the biosynthetic pathway of the sweet triterpenoid glycoside mogroside V, which has a sweetening strength of 250 times that of sucrose and is derived from mature fruit of luo-han-guo (Siraitia grosvenorii, monk fruit). A whole-genome sequencing of Siraitia, leading to a preliminary draft of the genome, was combined with an extensive transcriptomic analysis of developing fruit. A functional expression survey of nearly 200 candidate genes identified the members of the five enzyme families responsible for the synthesis of mogroside V: squalene epoxidases, triterpenoid synthases, epoxide hydrolases, cytochrome P450s, and UDP-glucosyltransferases. Protein modeling and docking studies corroborated the experimentally proven functional enzyme activities and indicated the order of the metabolic steps in the pathway. A comparison of the genomic organization and expression patterns of these Siraitia genes with the orthologs of other Cucurbitaceae implicates a strikingly coordinated expression of the pathway in the evolution of this species-specific and valuable metabolic pathway. The genomic organization of the pathway genes, syntenously preserved among the Cucurbitaceae, indicates, on the other hand, that gene clustering cannot account for this novel secondary metabolic pathway.

Italian horticultural and culinary records of summer squash (Cucurbita pepo, Cucurbitaceae) and emergence of the zucchini in 19th-century Milan.

BACKGROUND AND AIMS: Summer squash, the young fruits of Cucurbita pepo, are a common, high-value fruit vegetable. Of the summer squash, the zucchini, C. pepo subsp. pepo Zucchini Group, is by far the most cosmopolitan. The zucchini is easily distinguished from other summer squash by its uniformly cylindrical shape and intense colour. The zucchini is a relatively new cultivar-group of C. pepo, the earliest known evidence for its existence having been a description in a book on horticulture published in Milan in 1901. For this study, Italian-language books on agriculture and cookery dating from the 16th to 19th centuries have been collected and searched in an effort to follow the horticultural development and culinary use of young Cucurbita fruits in Italy. FINDINGS: The results indicate that Cucurbita fruits, both young and mature, entered Italian kitchens by the mid-16th century. A half-century later, round and elongate young fruits of C. pepo were addressed as separate cookery items and the latter had largely replaced the centuries-old culinary use of young, elongate bottle gourds, Lagenaria siceraria Allusion to a particular, extant cultivar of the longest fruited C. pepo, the Cocozelle Group, dates to 1811 and derives from the environs of Naples. The Italian diminutive word zucchini arose by the beginning of the 19th century in Tuscany and referred to small, mature, desiccated bottle gourds used as containers to store tobacco. By the 1840s, the Tuscan word zucchini was appropriated to young, primarily elongate fruits of C. pepo The Zucchini Group traces its origins to the environs of Milan, perhaps as early as 1850. The word zucchini and the horticultural product zucchini arose contemporaneously but independently. The results confirm that the Zucchini Group is the youngest of the four cultivar-groups of C. pepo subsp. pepo but it emerged approximately a half-century earlier than previously known.

Origin and emergence of the sweet dessert watermelon, Citrullus lanatus.

BACKGROUND AND AIMS: Watermelons, Citrullus species (Cucurbitaceae), are native to Africa and have been cultivated since ancient times. The fruit flesh of wild watermelons is watery, but typically hard-textured, pale-coloured and bland or bitter. The familiar sweet dessert watermelons, C. lanatus, featuring non-bitter, tender, well-coloured flesh, have a narrow genetic base, suggesting that they originated from a series of selection events in a single ancestral population. The objective of the present investigation was to determine where dessert watermelons originated and the time frame during which sweet dessert watermelons emerged. KEY FINDINGS: Archaeological remains of watermelons, mostly seeds, that date from 5000 years ago have been found in northeastern Africa. An image of a large, striped, oblong fruit on a tray has been found in an Egyptian tomb that dates to at least 4000 years ago. The Greek word pepon, Latin pepo and Hebrew avattiah of the first centuries CE were used for the same large, thick-rinded, wet fruit which, evidently, was the watermelon. Hebrew literature from the end of the second century CE and Latin literature from the beginning of the sixth century CE present watermelons together with three sweet fruits: figs, table grapes and pomegranates. Wild and primitive watermelons have been observed repeatedly in Sudan and neighbouring countries of northeastern Africa. CONCLUSIONS: The diverse evidence, combined, indicates that northeastern Africa is the centre of origin of the dessert watermelon, that watermelons were domesticated for water and food there over 4000 years ago, and that sweet dessert watermelons emerged in Mediterranean lands by approximately 2000 years ago. Next-generation ancient-DNA sequencing and state-of-the-art genomic analysis offer opportunities to rigorously assess the relationships among ancient and living wild and primitive watermelons from northeastern Africa, modern sweet dessert watermelons and other Citrullus taxa.

Cucurbits depicted in Byzantine mosaics from Israel, 350-600 ce.

BACKGROUND AND AIMS: Thousands of floor mosaics were produced in lands across the Roman and Byzantine empires. Some mosaics contain depictions of agricultural produce, potentially providing useful information concerning the contemporary presence and popularity of crop plants in a particular geographical region. Hundreds of floor mosaics produced in Israel during the Byzantine period have survived. The objective of the present work was to search these mosaics for Cucurbitaceae in order to obtain a more complete picture of cucurbit crop history in the eastern Mediterranean region. RESULTS AND CONCLUSIONS: Twenty-three mosaics dating from 350-600 ce were found that had images positively identifiable as cucurbits. The morphological diversity of the cucurbit fruits in the mosaics of Israel is greater than that appearing in mosaics from any other Roman or Byzantine provincial area. The depicted fruits vary in shape from oblate to extremely long, and some are furrowed, others are striped and others lack definite markings. The cucurbit taxa depicted in the mosaics are Cucumis melo (melon), Citrullus lanatus (watermelon), Luffa aegyptiaca (sponge gourd) and Lagenaria siceraria (bottle gourd). Cucumis melo is the most frequently found taxon in the mosaics and is represented by round dessert melons and long snake melons. Fruits of at least two cultivars of snake melons and of watermelons are represented. To our knowledge, images of sponge gourds have not been found in Roman and Byzantine mosaics elsewhere. Indeed, the mosaics of Israel contain what are probably the oldest depictions of Luffa aegyptiaca in Mediterranean lands. Sponge gourds are depicted often, in 11 of the mosaics at eight localities, and the images include both mature fruits, which are useful for cleaning and washing, and immature fruits, which are edible. Only one mosaic has images positively identifiable as of bottle gourds, and these were round-pyriform and probably used as vessels.

Medieval iconography of watermelons in Mediterranean Europe.

BACKGROUND AND AIMS: The watermelon, Citrullus lanatus (Cucurbitaceae), is an important fruit vegetable in the warmer regions of the world. Watermelons were illustrated in Mediterranean Antiquity, but not as frequently as some other cucurbits. Little is known concerning the watermelons of Mediterranean Europe during medieval times. With the objective of obtaining an improved understanding of watermelon history and diversity in this region, medieval drawings purportedly of watermelons were collected, examined and compared for originality, detail and accuracy. FINDINGS: The oldest manuscript found that contains an accurate, informative image of watermelon is the Tractatus de herbis, British Library ms. Egerton 747, which was produced in southern Italy, around the year 1300. A dozen more original illustrations were found, most of them from Italy, produced during the ensuing two centuries that can be positively identified as watermelon. In most herbal-type manuscripts, the foliage is depicted realistically, the plants shown as having long internodes, alternate leaves with pinnatifid leaf laminae, and the fruits are small, round and striped. The manuscript that contains the most detailed and accurate image of watermelon is the Carrara Herbal, British Library ms. Egerton 2020. In the agriculture-based manuscripts, the foliage, if depicted, is not accurate, but variation in the size, shape and coloration of the fruits is evident. Both red-flesh and white-flesh watermelons are illustrated, corresponding to the typical sweet dessert watermelons so common today and the insipid citron watermelons, respectively. The variation in watermelon fruit size, shape and coloration depicted in the illustrations indicates that at least six cultivars of watermelon are represented, three of which probably had red, sweet flesh and three of which appear to have been citrons. Evidently, citron watermelons were more common in Mediterranean Europe in the past than they are today.

Genetic relationships and evolution in Cucurbita pepo (pumpkin, squash, gourd) as revealed by simple sequence repeat polymorphisms.

Genetic relationships among 104 accessions of Cucurbita pepo were assessed from polymorphisms in 134 SSR (microsatellite) and four SCAR loci, yielding a total of 418 alleles, distributed among all 20 linkage groups. Genetic distance values were calculated, a dendrogram constructed, and principal coordinate analyses conducted. The results showed 100 of the accessions as distributed among three clusters representing each of the recognized subspecies, pepo, texana, and fraterna. The remaining four accessions, all having very small, round, striped fruits, assumed central positions between the two cultivated subspecies, pepo and texana, suggesting that they are relicts of undescribed wild ancestors of the two domesticated subspecies. In both, subsp. texana and subsp. pepo, accessions belonging to the same cultivar-group (fruit shape) associated with one another. Within subsp. pepo, accessions grown for their seeds or that are generalists, used for both seed and fruit consumption, assumed central positions. Specialized accessions, grown exclusively for consumption of their young fruits, or their mature fruit flesh, or seed oil extraction, tended to assume outlying positions, and the different specializations radiated outward from the center in different directions. Accessions of the longest-fruited cultivar-group, Cocozelle, radiated bidirectionally, indicating independent selection events for long fruits in subsp. pepo probably driven by a common desire to consume the young fruits. Among the accessions tested, there was no evidence for crossing between subspecies after domestication.

Medieval emergence of sweet melons, Cucumis melo (Cucurbitaceae).

BACKGROUND: Sweet melons, Cucumis melo, are a widely grown and highly prized crop. While melons were familiar in antiquity, they were grown mostly for use of the young fruits, which are similar in appearance and taste to cucumbers, C. sativus. The time and place of emergence of sweet melons is obscure, but they are generally thought to have reached Europe from the east near the end of the 15th century. The objective of the present work was to determine where and when truly sweet melons were first developed. METHODS: Given their large size and sweetness, melons are often confounded with watermelons, Citrullus lanatus, so a list was prepared of the characteristics distinguishing between them. An extensive search of literature from the Roman and medieval periods was conducted and the findings were considered in their context against this list and particularly in regard to the use of the word 'melon' and of adjectives for sweetness and colour. FINDINGS: Medieval lexicographies and an illustrated Arabic translation of Dioscorides' herbal suggest that sweet melons were present in Central Asia in the mid-9th century. A travelogue description indicates the presence of sweet melons in Khorasan and Persia by the mid-10th century. Agricultural literature from Andalusia documents the growing of sweet melons, evidently casabas (Inodorous Group), there by the second half of the 11th century, which probably arrived from Central Asia as a consequence of Islamic conquest, trade and agricultural development. Climate and geopolitical boundaries were the likely causes of the delay in the spread of sweet melons into the rest of Europe.

Occidental diffusion of cucumber (Cucumis sativus) 500-1300 CE: two routes to Europe.

BACKGROUND: The cucumber, Cucumis sativus, is one of the most widely consumed fruit vegetables the world over. The history of its dispersal to the Occident from its centre of origin, the Indian subcontinent, has been incorrectly understood for some time, due to the confusion of cucumbers with vegetable melons. Iconographic and literary evidence has shown that cucumber was absent in Roman times, up to 500 CE, but present in Europe by late medieval times, 1300. The objective of the present investigation was to determine more accurately when the cucumber arrived in Europe and by what route. FINDINGS AND CONCLUSIONS: The evidence for the movement of C. sativus westward is entirely lexicographical until the 10th century. Syriac, Persian and Byzantine Greek sources suggest the presence of cucumbers, to the east and north-east of the Mediterranean Sea (modern Iran, Iraq and Turkey), by the 6th or 7th century. Arabic medical writings suggest the presence of cucumbers in Spain as early as the mid-9th century and in Tunisia by the early 10th century. Descriptive evidence in Arabic establishes the presence of cucumbers in Andalusia by the second half of the 10th century. Latin translations from Arabic sources indicate the presence of cucumbers in southern Italy by the second half of the 11th century. These writings, together with lexicographical discrepancies in names of cucurbits in late medieval Latin writings, suggest that cucumber was introduced to Europe by two independent diffusions. One diffusion appears to have been overland from Persia into eastern and northern Europe and preceded the Islamic conquests. The other, subsequent diffusion into western and southern Europe, was probably by a mostly maritime route from Persia or the Indian subcontinent into Andalusia.

Medieval herbal iconography and lexicography of Cucumis (cucumber and melon, Cucurbitaceae) in the Occident, 1300-1458.

BACKGROUND: The genus Cucumis contains two species of important vegetable crops, C. sativus, cucumber, and C. melo, melon. Melon has iconographical and textual records from lands of the Mediterranean Basin dating back to antiquity, but cucumber does not. The goal of this study was to obtain an improved understanding of the history of these crops in the Occident. Medieval images purportedly of Cucumis were examined, their specific identity was determined and they were compared for originality, accuracy and the lexicography of their captions. FINDINGS: The manuscripts having accurate, informative images are derived from Italy and France and were produced between 1300 and 1458. All have an illustration of cucumber but not all contain an image of melon. The cucumber fruits are green, unevenly cylindrical with an approx. 2:1 length-to-width ratio. Most of the images show the cucumbers marked by sparsely distributed, large dark dots, but images from northern France show them as having densely distributed, small black dots. The different size, colour and distribution reflect the different surface wartiness and spininess of modern American and French pickling cucumbers. The melon fruits are green, oval to serpentine, closely resembling the chate and snake vegetable melons, but not sweet melons. In nearly all manuscripts of Italian provenance, the cucumber image is labelled with the Latin caption citruli, or similar, plural diminuitive of citrus (citron, Citrus medica). However, in manuscripts of French provenance, the cucumber image is labelled cucumeres, which is derived from the classical Latin epithet cucumis for snake melon. The absence of melon in some manuscripts and the expropriation of the Latin cucumis/cucumer indicate replacement of vegetable melons by cucumbers during the medieval period in Europe. One image, from British Library ms. Sloane 4016, has a caption that allows tracing of the word 'gherkin' back to languages of the geographical nativity of C. sativus, the Indian subcontinent.

Genes for resistance to zucchini yellow mosaic in tropical pumpkin.

Four cultigens of Cucurbita moschata resistant to zucchini yellow mosaic virus were crossed with the susceptible 'Waltham Butternut' and with each other in order to clarify the mode of inheritance of resistance and relationships among the genes involved. Five loci were segregating, with genes for resistance Zym-0 and Zym-4 carried by 'Nigerian Local' and one of them also carried by 'Nicklow's Delight,' Zym-1 carried by 'Menina,' and zym-6 carried by 'Soler.' A recessive gene carried by 'Waltham Butternut,' zym-5, is complementary with the dominant Zym-4 of 'Nigerian Local,' that is, the resistance conferred by Zym-4 is only expressed in zym-5/zym-5 individuals. Gene zym-6 appears to be linked to either Zym-0 or Zym-4, and it is also possible that Zym-1 is linked to one of them as well.

Comparative Metabolomics and Molecular Phylogenetics of Melon (Cucumis melo, Cucurbitaceae) Biodiversity.

The broad variability of Cucumis melo (melon, Cucurbitaceae) presents a challenge to conventional classification and organization within the species. To shed further light on the infraspecific relationships within C. melo, we compared genotypic and metabolomic similarities among 44 accessions representative of most of the cultivar-groups. Genotyping-by-sequencing (GBS) provided over 20,000 single-nucleotide polymorphisms (SNPs). Metabolomics data of the mature fruit flesh and rind provided over 80,000 metabolomic and elemental features via an orchestra of six complementary metabolomic platforms. These technologies probed polar, semi-polar, and non-polar metabolite fractions as well as a set of mineral elements and included both flavor- and taste-relevant volatile and non-volatile metabolites. Together these results enabled an estimate of "metabolomic/elemental distance" and its correlation with the genetic GBS distance of melon accessions. This study indicates that extensive and non-targeted metabolomics/elemental characterization produced classifications that strongly, but not completely, reflect the current and extensive genetic classification. Certain melon Groups, such as Inodorous, clustered in parallel with the genetic classifications while other genome to metabolome/element associations proved less clear. We suggest that the combined genomic, metabolic, and element data reflect the extensive sexual compatibility among melon accessions and the breeding history that has, for example, targeted metabolic quality traits, such as taste and flavor.

The Cucurbitaceae and Solanaceae illustrated in medieval manuscripts known as the Tacuinum Sanitatis.

BACKGROUND AND AIMS: Beginning in the last two decades of the 14th century, richly illuminated versions of the Tacuinum Sanitatis, the Latin translation of an 11th-century Arabic manuscript known as Taqwim al-Sihha bi al-Ashab al-Sitta, were produced in northern Italy. These illustrated manuscripts provide a window on late medieval life in that region by containing some 200 full-page illustrations, many of which vividly depict the harvest of vegetables, fruits, flowers, grains, aromatics and medicinal plants. Our objective was to search for and identify the images of taxa of Cucurbitaceae and Solanaceae. METHODS: We have located all reported illustrated Tacuinum Sanitatis and similar or related manuscripts, searched through printed or electronic reproductions of them, categorized six of them that display full-page illustrations as archetypic, and established the identity of the Cucurbitaceae and Solanaceae appearing in these six manuscripts. KEY RESULTS AND CONCLUSIONS: Of the Cucurbitaceae, Cucumis sativus (short-fruited cucumbers), Cucumis melo (including round as well as elongate melons), Citrullus lanatus (both sweet watermelons and citrons), and Lagenaria siceraria (including bottle-shaped as well as long gourds), are illustrated. Of the Solanaceae, Solanum melongena (egg-shaped purple aubergines) and Mandragora sp. (mandrake) are illustrated. These depictions include some of the earliest known images of cucumber, casaba melon (Cucumis melo Inodorous Group) and aubergine, each of which closely resembles an extant cultivar-group or market type. Overall, the botanically most accurate images are in the version of the Tacuinum located in the Osterreichische Nationalbibliothek, Vienna, cod. ser. n. 2644. Similarities and differences in botanical accuracy among the images of Cucurbitaceae and Solanaceae in the six archetypal Tacuinum manuscripts suggest to us that another illustrated Tacuinum, now lost, may have antedated and served as a model or inspiration for the six surviving archetypic manuscripts.

Genes for "Reverse" fruit striping in squash (Cucurbita pepo).

Longitudinal striping is a common fruit color pattern in Cucurbita pepo and is conferred by any of several alleles at the light coloration-1 locus. Normally, dark stripes appear over the fruit surface areas between the 10 main subepidermal vein tracts with the lighter background color over and adjacent to these vein tracts. Less commonly, the striping is "reversed," that is, lighter than the background color. The present work was conducted to elucidate the mode of inheritance of reverse striping. The results indicated that reverse striping is conferred by the complementary interaction of an allele for striping with a heretofore unidentified allele at the light coloration-2 locus which is hereby designated l-2(R). Fruits of plants carrying an allele for striping and that are homozygous for l-2(R) have completely reversed striping, whereas those heterozygous for l-2(R) have striping that is completely normal or that is partially normal and partially reversed.

Whole-genome resequencing of Cucurbita pepo morphotypes to discover genomic variants associated with morphology and horticulturally valuable traits.

Cucurbita pepo contains two cultivated subspecies, each of which encompasses four fruit-shape morphotypes (cultivar groups). The Pumpkin, Vegetable Marrow, Cocozelle, and Zucchini Groups are of subsp. pepo and the Acorn, Crookneck, Scallop, and Straightneck Groups are of subsp. ovifera. Recently, a de novo assembly of the C. pepo subsp. pepo Zucchini genome was published, providing insights into its evolution. To expand our knowledge of evolutionary processes within C. pepo and to identify variants associated with particular morphotypes, we performed whole-genome resequencing of seven of these eight C. pepo morphotypes. We report for the first time whole-genome resequencing of the four subsp. pepo (Pumpkin, Vegetable Marrow, Cocozelle, green Zucchini, and yellow Zucchini) morphotypes and three of the subsp. ovifera (Acorn, Crookneck, and Scallop) morphotypes. A high-depth resequencing approach was followed, using the BGISEQ-500 platform that enables the identification of rare variants, with an average of 33.5X. Approximately 94.5% of the clean reads were mapped against the reference Zucchini genome. In total, 3,823,977 high confidence single-nucleotide polymorphisms (SNPs) were identified. Within each accession, SNPs varied from 636,918 in green Zucchini to 2,656,513 in Crookneck, and were distributed homogeneously along the chromosomes. Clear differences between subspecies pepo and ovifera in genetic variation and linkage disequilibrium are highlighted. In fact, comparison between subspecies pepo and ovifera indicated 5710 genes (22.5%) with Fst > 0.80 and 1059 genes (4.1%) with Fst = 1.00 as potential candidate genes that were fixed during the independent evolution and domestication of the two subspecies. Linkage disequilibrium was greater in subsp. ovifera than in subsp. pepo, perhaps reflective of the earlier differentiation of morphotypes within subsp. ovifera. Some morphotype-specific genes have been localized. Our results offer new clues that may provide an improved understanding of the underlying genomic regions involved in the independent evolution and domestication of the two subspecies. Comparisons among SNPs unique to particular subspecies or morphotypes may provide candidate genes responsible for traits of high economic importance.

Differential expression of cucumber RNA-dependent RNA polymerase 1 genes during antiviral defence and resistance.

RNA-dependent RNA polymerase 1 (RDR1) plays a crucial role in plant defence against viruses. In this study, it was observed that cucumber, Cucumis sativus, uniquely encodes a small gene family of four RDR1 genes. The cucumber RDR1 genes (CsRDR1a, CsRDR1b and duplicated CsRDR1c1/c2) shared 55%-60% homology in their encoded amino acid sequences. In healthy cucumber plants, RDR1a and RDR1b transcripts were expressed at higher levels than transcripts of RDR1c1/c2, which were barely detectable. The expression of all four CsRDR1 genes was induced by virus infection, after which the expression level of CsRDR1b increased 10-20-fold in several virus-resistant cucumber cultivars and in a broad virus-resistant transgenic cucumber line expressing a high level of transgene small RNAs, all without alteration in salicylic acid (SA) levels. By comparison, CsRDR1c1/c2 genes were highly induced (25-1300-fold) in susceptible cucumber cultivars infected with RNA or DNA viruses. Inhibition of RDR1c1/c2 expression led to increased virus accumulation. Ectopic application of SA induced the expression of cucumber RDR1a, RDR1b and RDRc1/c2 genes. A constitutive high level of RDR1b gene expression independent of SA was found to be associated with broad virus resistance. These findings show that multiple RDR1 genes are involved in virus resistance in cucumber and are regulated in a coordinated fashion with different expression profiles.

The cucurbits of mediterranean antiquity: identification of taxa from ancient images and descriptions.

BACKGROUND: A critical analysis was made of cucurbit descriptions in Dioscorides' De Materia Medica, Columella's De Re Rustica and Pliny's Historia Naturalis, works on medicine, agriculture and natural science of the 1st century ce, as well as the Mishna and Tosefta, compilations of rabbinic law derived from the same time period together with cucurbit images dating from antiquity including paintings, mosaics and sculpture. The goal was to identify taxonomically the Mediterranean cucurbits at the time of the Roman Empire. FINDINGS: By ancient times, long-fruited forms of Cucumis melo (melon) and Lagenaria siceraria (bottle gourd) were selected, cultivated and used as vegetables around the Mediterranean and, in addition, bottle-shaped fruits of L. siceraria were employed as vessels. Citrullus lanatus (watermelons) and round-fruited forms of Cucumis melo (melons) were also consumed, but less commonly. A number of cucurbit species, including Bryonia alba, B. dioica, Citrullus colocynthis and Ecballium elaterium, were employed for medicinal purposes. No unequivocal evidence was found to suggest the presence of Cucumis sativus (cucumber) in the Mediterranean area during this era. The cucumis of Columella and Pliny was not cucumber, as commonly translated, but Cucumis melo subsp. melo Flexuosus Group (snake melon or vegetable melon).

Dual role of the pigmentation gene B in affecting carotenoid and vitamin E content in squash (Cucurbita pepo) mesocarp.

The yellow and orange colorations of the mesocarp of pumpkins and squash of Cucurbita pepo are due to the presence of carotenoid pigments that also greatly contribute to their nutritional value. Carotenoids, as well as tocopherols (vitamin E), are isoprenoid compounds formed by branches of a common biosynthetic pathway. Photodiode array HPLC analysis was used to simultaneously determine the content and composition of fruit-flesh carotenoids and tocopherols in five pairs of near-isogenic lines differing in the allelic state of genes previously identified as having profound effects on fruit color. The dominant B allele promoted carotenoid accumulation up to 5-fold and prevented tocopherol accumulation in all genetic backgrounds. The dominant L-2 allele doubled carotenoid content and, in combination with the dominant B allele, increased carotenoid content by 10-15-fold as compared to the recessive l-2 allele. The genes D and L-1 had no significant effects on mesocarp tocopherols or carotenoids content. These results indicate that the B gene, which affects both carotenoids and tocopherols, may play a regulatory role in the flux of the isoprenoid pathway products.

Reconstruction of skull defects in the middle ages and renaissance.

In Egyptian, Greco-Roman, and Arabic medicine, the closure of a skull defect was not provided at the end of a therapeutic trepanation or in cases of bone removal. The literature from the Middle Ages and Renaissance disclosed some striking and forgotten practices. Gilbertus Anglicus (c. 1180 to c. 1250) cites the use of a piece of a cup made from wooden bowl (ciphum or mazer) or a gold sheet to cover the gap and protect the brain in these patients; this citation probably reflected a widely known folk practice. Pietro d'Argellata introduced the use of a fixed piece of dried gourd for brain protection to reconstruct a skull defect. In the late Renaissance, the negative folklore describing this outlandish practice likely led to the use of silver and lead sheets. Nevertheless, for centuries, large numbers of surgeons preferred to leave the dura mater uncovered after bone removal, and failed to apply any brain protection.