Fruit quality is determined by numerous genetic factors that affect taste, aroma, shape, color, t... more Fruit quality is determined by numerous genetic factors that affect taste, aroma, shape, color, texture, nutritional value and shelf life. To unravel the genetic component involved in regulating the metabolic pathways behind these traits, relationships between genotypes, metabolites and gene expression are being studied. The research strategy is based on a population of recombinant inbred lines (RILs) of melon (Cucumis melo) derived from two phenotypically and genetically diverse parents (‘Dulce’ and ‘PI414723’). This population resource has been mapped with over 800 molecular markers, allowing for association analyses with fruit quality, metabolic traits and gene expression QTLs. Metabolic data are being collected using both targeted (sugars, organic acids, carotenoids, ethylene, chlorophyll, volatiles) and non-targeted methods of metabolomic analyses. Presently, transcriptomic data are being obtained from mature fruits of the RIL population, using the Illumina/Solexa sequencing te...
Introduction: Several studies have applied various marker types (including RFLP, RAPD, AFLP and S... more Introduction: Several studies have applied various marker types (including RFLP, RAPD, AFLP and SSR) for mapping and assessing genetic variation within C. melo (1, 3, 6, 7). A partial linkage map of melon from a cross between PI 414723 (C. melo Group Acidulus) and 'Dulce' (C. melo Group Reticulatus) was previously described by us (2). Single nucleotide polymorphisms (SNPs) are an abundant form of genetic variation in the genome of various species that are extremely useful for gene mapping and phylogenetic studies. In recent years, SNPs have become important as genomic markers with numerous technical methods developed for their detection (4). In this study, SNP markers for genes belonging to major fruit metabolic pathways were developed. In order to link between these markers and fruit quality traits, these SNPs are currently being located on the PI 414723 × 'Dulce' map. Materials and Methods: Plant material. The F 2 mapping population included 112 individuals derived...
Melon (Cucumis melo) fruits exhibit phenotypic diversity in several key quality determinants such... more Melon (Cucumis melo) fruits exhibit phenotypic diversity in several key quality determinants such as taste, color and aroma. Sucrose, carotenoids and volatiles are recognized as the key compounds shaping the above corresponding traits yet the full network of biochemical events underlying their synthesis have not been comprehensively described. To delineate the cellular processes shaping fruit quality phenotypes, a population of recombinant inbred lines (RIL) was used as a source of phenotypic and genotypic variations. In parallel, ripe fruits were analyzed for both the quantified level of 77 metabolic traits directly associated with fruit quality and for RNA-seq based expression profiles generated for 27,000 unigenes. First, we explored inter-metabolite association patterns; then, we described metabolites versus gene association patterns; finally, we used the correlation-based associations for predicting uncharacterized synthesis pathways.
The Plant journal : for cell and molecular biology, Jan 6, 2015
Melon (Cucumis melo) flesh color is genetically determined and can be white, light green or orang... more Melon (Cucumis melo) flesh color is genetically determined and can be white, light green or orange with β-carotene being the predominant pigment. We associated carotenoid accumulation in melon fruit flesh with polymorphism within CmOr, a homolog of the cauliflower BoOr gene, and identified CmOr as the previously described gf locus in melon. CmOr was found to co-segregate with fruit flesh color and presented two haplotypes (alleles) in a broad germplasm collection, one being associated with orange flesh and the second with either white or green flesh. Allelic variation of CmOr does not affect its transcription or protein level. The variation also does not affect its plastid subcellular localization. Among the identified SNPs between CmOr alleles in orange versus green/white-flesh fruit, a single SNP causes a change of an evolutionarily highlyconserved arginine to histidine in the CmOr protein. Functional analysis of CmOr haplotypes in an Arabidopsis callus system confirmed the abilit...
... Vitaly Portnoy, Alex Diber, Sarah Pollock, Hagai Karchi, Shery Lev, Galil Tzuri, Rotem Harel-... more ... Vitaly Portnoy, Alex Diber, Sarah Pollock, Hagai Karchi, Shery Lev, Galil Tzuri, Rotem Harel-Beja, Relly Forer, Vitaly H. Portnoy, Efraim ... genes also included genes for volatile metabolism, such as alcohol acetyltrasferase (Aharoni et al., 2000; Shalit et al., 2001; Yahyaoui et al ...
The availability of sequence information for many plants has opened the way to advanced genetic a... more The availability of sequence information for many plants has opened the way to advanced genetic analysis in many non-model plants. Nevertheless, exploration of genetic variation on a large scale and its use as a tool for the identification of traits of interest are still rare. In this study, we combined a bulk segregation approach with our own-designed microarrays to map the pH locus that influences fruit pH in melon. Using these technologies, we identified a set of markers that are genetically linked to the pH trait. Further analysis using a set of melon cultivars demonstrated that some of these markers are tightly linked to the pH trait throughout our germplasm collection. These results validate the utility of combining microarray technology with a bulk segregation approach in mapping traits of interest in non-model plants.
The sweet melon fruit is characterized by a metabolic transition during its development that lead... more The sweet melon fruit is characterized by a metabolic transition during its development that leads to extensive accumulation of the disaccharide sucrose in the mature fruit. While the biochemistry of the sugar metabolism pathway of the cucurbits has been well studied, a comprehensive analysis of the pathway at the transcriptional level allows for a global genomic view of sugar metabolism during fruit sink development. We identified 42 genes encoding the enzymatic reactions of the sugar metabolism pathway in melon. The expression pattern of the 42 genes during fruit development of the sweet melon cv Dulce was determined from a deep sequencing analysis performed by 454 pyrosequencing technology, comprising over 350,000 transcripts from four stages of developing melon fruit flesh, allowing for digital expression of the complete metabolic pathway. The results shed light on the transcriptional control of sugar metabolism in the developing sweet melon fruit, particularly the metabolic transition to sucrose accumulation, and point to a concerted metabolic transition that occurs during fruit development.
DNA fingerprinting analysis of genetic relatedness between carnation genotypes using human derive... more DNA fingerprinting analysis of genetic relatedness between carnation genotypes using human derived minisatellite probes, correctly reflected relationships within and between categories of carnation plants with inferred relatedness. Similar DNA fingerprint patterns were observed between genotypes within either 'standard' or 'spray' categories. A high level of similarity was also detected between those categories. Moderate similarities were found within the 'dwarf' category, and between 'dwarf' and either 'standard' or 'spray' categories. Large differences were observed between a wild species and cultivated categories. Abbreviations: b.l. -breeding line, BS -band-sharing
A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over th... more A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over the last two decades. However, these maps were constructed using different marker sets, thus, making comparative analysis among maps difficult. In order to solve this problem, a consensus genetic map in melon was constructed using primarily highly transferable anchor markers that have broad potential use for mapping, synteny, and comparative quantitative trait loci (QTL) analysis, increasing breeding effectiveness and efficiency via marker-assisted selection (MAS).
Background: Genetic maps constitute the basis of breeding programs for many agricultural organism... more Background: Genetic maps constitute the basis of breeding programs for many agricultural organisms. The creation of these maps is dependent on marker discovery. Melon, among other crops, is still lagging in genomic resources, limiting the ability to discover new markers in a high-throughput fashion. One of the methods used to search for molecular markers is DNA hybridization to microarrays. Microarray hybridization of DNA from different accessions can reveal differences between them--single-feature polymorphisms (SFPs). These SFPs can be used as markers for breeding purposes, or they can be converted to conventional markers by sequencing. This method has been utilized in a few different plants to discover genetic variation, using Affymetrix arrays that exist for only a few organisms. We applied this approach with some modifications for marker discovery in melon.
In order to broaden the available genetic variation of melon, we developed an ethyl methanesulfon... more In order to broaden the available genetic variation of melon, we developed an ethyl methanesulfonate mutation library in an orange-flesh 'Charentais' type melon line that accumulates β-carotene. One mutagenized M2 family segregated for a novel recessive trait, a yellow-orange fruit flesh ('yofI'). HPLC analysis revealed that 'yofI' accumulates pro-lycopene (tetra-cis-lycopene) as its major fruit pigment. The altered carotenoid composition of 'yofI' is associated with a significant change of the fruit aroma since cleavage of β-carotene yields different apocarotenoids than the cleavage of pro-lycopene. Normally, pro-lycopene is further isomerized by CRTISO (carotenoid isomerase) to yield all-trans-lycopene, which is further cyclized to β-carotene in melon fruit. Cloning and sequencing of 'yofI' CRTISO identified two mRNA sequences which lead to truncated forms of CRTISO. Sequencing of the genomic CRTISO identified an A-T transversion in 'yofI' which leads to a premature STOP codon. The early carotenoid pathway genes were up regulated in yofI fruit causing accumulation of other intermediates such as phytoene and ζ-carotene. Total carotenoid levels are only slightly increased in the mutant. Mutants accumulating pro-lycopene have been reported in both tomato and watermelon fruits, however, this is the first report of a non-lycopene accumulating fruit showing this phenomenon.
Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor "Candidatus Portiera aley... more Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor "Candidatus Portiera aleyrodidarum," an obligatory symbiotic bacterium which is housed in a special organ called the bacteriome. These insects are also home for a diverse facultative microbial community which may include Hamiltonella, Arsenophonus, Fritchea, Wolbachia, and Cardinium spp. In this study, the bacteria associated with a B biotype of the sweet potato whitefly Bemisia tabaci were characterized using molecular fingerprinting techniques, and a Rickettsia sp. was detected for the first time in this insect family. Rickettsia sp. distribution, transmission and localization were studied using PCR and fluorescence in situ hybridizations (FISH). Rickettsia was found in all 20 Israeli B. tabaci populations screened but not in all individuals within each population. A FISH analysis of B. tabaci eggs, nymphs, and adults revealed a unique concentration of Rickettsia around the gut and follicle cells, as well as a random distribution in the hemolymph. We postulate that the Rickettsia enters the oocyte together with the bacteriocytes, leaves these symbionthousing cells when the egg is laid, multiplies and spreads throughout the egg during embryogenesis and, subsequently, disperses throughout the body of the hatching nymph, excluding the bacteriomes. Although the role Rickettsia plays in the biology of the whitefly is currently unknown, the vertical transmission on the one hand and the partial within-population infection on the other suggest a phenotype that is advantageous under certain conditions but may be deleterious enough to prevent fixation under others.
Fruit quality is determined by numerous genetic factors that affect taste, aroma, shape, color, t... more Fruit quality is determined by numerous genetic factors that affect taste, aroma, shape, color, texture, nutritional value and shelf life. To unravel the genetic component involved in regulating the metabolic pathways behind these traits, relationships between genotypes, metabolites and gene expression are being studied. The research strategy is based on a population of recombinant inbred lines (RILs) of melon (Cucumis melo) derived from two phenotypically and genetically diverse parents (‘Dulce’ and ‘PI414723’). This population resource has been mapped with over 800 molecular markers, allowing for association analyses with fruit quality, metabolic traits and gene expression QTLs. Metabolic data are being collected using both targeted (sugars, organic acids, carotenoids, ethylene, chlorophyll, volatiles) and non-targeted methods of metabolomic analyses. Presently, transcriptomic data are being obtained from mature fruits of the RIL population, using the Illumina/Solexa sequencing te...
Introduction: Several studies have applied various marker types (including RFLP, RAPD, AFLP and S... more Introduction: Several studies have applied various marker types (including RFLP, RAPD, AFLP and SSR) for mapping and assessing genetic variation within C. melo (1, 3, 6, 7). A partial linkage map of melon from a cross between PI 414723 (C. melo Group Acidulus) and 'Dulce' (C. melo Group Reticulatus) was previously described by us (2). Single nucleotide polymorphisms (SNPs) are an abundant form of genetic variation in the genome of various species that are extremely useful for gene mapping and phylogenetic studies. In recent years, SNPs have become important as genomic markers with numerous technical methods developed for their detection (4). In this study, SNP markers for genes belonging to major fruit metabolic pathways were developed. In order to link between these markers and fruit quality traits, these SNPs are currently being located on the PI 414723 × 'Dulce' map. Materials and Methods: Plant material. The F 2 mapping population included 112 individuals derived...
Melon (Cucumis melo) fruits exhibit phenotypic diversity in several key quality determinants such... more Melon (Cucumis melo) fruits exhibit phenotypic diversity in several key quality determinants such as taste, color and aroma. Sucrose, carotenoids and volatiles are recognized as the key compounds shaping the above corresponding traits yet the full network of biochemical events underlying their synthesis have not been comprehensively described. To delineate the cellular processes shaping fruit quality phenotypes, a population of recombinant inbred lines (RIL) was used as a source of phenotypic and genotypic variations. In parallel, ripe fruits were analyzed for both the quantified level of 77 metabolic traits directly associated with fruit quality and for RNA-seq based expression profiles generated for 27,000 unigenes. First, we explored inter-metabolite association patterns; then, we described metabolites versus gene association patterns; finally, we used the correlation-based associations for predicting uncharacterized synthesis pathways.
The Plant journal : for cell and molecular biology, Jan 6, 2015
Melon (Cucumis melo) flesh color is genetically determined and can be white, light green or orang... more Melon (Cucumis melo) flesh color is genetically determined and can be white, light green or orange with β-carotene being the predominant pigment. We associated carotenoid accumulation in melon fruit flesh with polymorphism within CmOr, a homolog of the cauliflower BoOr gene, and identified CmOr as the previously described gf locus in melon. CmOr was found to co-segregate with fruit flesh color and presented two haplotypes (alleles) in a broad germplasm collection, one being associated with orange flesh and the second with either white or green flesh. Allelic variation of CmOr does not affect its transcription or protein level. The variation also does not affect its plastid subcellular localization. Among the identified SNPs between CmOr alleles in orange versus green/white-flesh fruit, a single SNP causes a change of an evolutionarily highlyconserved arginine to histidine in the CmOr protein. Functional analysis of CmOr haplotypes in an Arabidopsis callus system confirmed the abilit...
... Vitaly Portnoy, Alex Diber, Sarah Pollock, Hagai Karchi, Shery Lev, Galil Tzuri, Rotem Harel-... more ... Vitaly Portnoy, Alex Diber, Sarah Pollock, Hagai Karchi, Shery Lev, Galil Tzuri, Rotem Harel-Beja, Relly Forer, Vitaly H. Portnoy, Efraim ... genes also included genes for volatile metabolism, such as alcohol acetyltrasferase (Aharoni et al., 2000; Shalit et al., 2001; Yahyaoui et al ...
The availability of sequence information for many plants has opened the way to advanced genetic a... more The availability of sequence information for many plants has opened the way to advanced genetic analysis in many non-model plants. Nevertheless, exploration of genetic variation on a large scale and its use as a tool for the identification of traits of interest are still rare. In this study, we combined a bulk segregation approach with our own-designed microarrays to map the pH locus that influences fruit pH in melon. Using these technologies, we identified a set of markers that are genetically linked to the pH trait. Further analysis using a set of melon cultivars demonstrated that some of these markers are tightly linked to the pH trait throughout our germplasm collection. These results validate the utility of combining microarray technology with a bulk segregation approach in mapping traits of interest in non-model plants.
The sweet melon fruit is characterized by a metabolic transition during its development that lead... more The sweet melon fruit is characterized by a metabolic transition during its development that leads to extensive accumulation of the disaccharide sucrose in the mature fruit. While the biochemistry of the sugar metabolism pathway of the cucurbits has been well studied, a comprehensive analysis of the pathway at the transcriptional level allows for a global genomic view of sugar metabolism during fruit sink development. We identified 42 genes encoding the enzymatic reactions of the sugar metabolism pathway in melon. The expression pattern of the 42 genes during fruit development of the sweet melon cv Dulce was determined from a deep sequencing analysis performed by 454 pyrosequencing technology, comprising over 350,000 transcripts from four stages of developing melon fruit flesh, allowing for digital expression of the complete metabolic pathway. The results shed light on the transcriptional control of sugar metabolism in the developing sweet melon fruit, particularly the metabolic transition to sucrose accumulation, and point to a concerted metabolic transition that occurs during fruit development.
DNA fingerprinting analysis of genetic relatedness between carnation genotypes using human derive... more DNA fingerprinting analysis of genetic relatedness between carnation genotypes using human derived minisatellite probes, correctly reflected relationships within and between categories of carnation plants with inferred relatedness. Similar DNA fingerprint patterns were observed between genotypes within either 'standard' or 'spray' categories. A high level of similarity was also detected between those categories. Moderate similarities were found within the 'dwarf' category, and between 'dwarf' and either 'standard' or 'spray' categories. Large differences were observed between a wild species and cultivated categories. Abbreviations: b.l. -breeding line, BS -band-sharing
A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over th... more A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over the last two decades. However, these maps were constructed using different marker sets, thus, making comparative analysis among maps difficult. In order to solve this problem, a consensus genetic map in melon was constructed using primarily highly transferable anchor markers that have broad potential use for mapping, synteny, and comparative quantitative trait loci (QTL) analysis, increasing breeding effectiveness and efficiency via marker-assisted selection (MAS).
Background: Genetic maps constitute the basis of breeding programs for many agricultural organism... more Background: Genetic maps constitute the basis of breeding programs for many agricultural organisms. The creation of these maps is dependent on marker discovery. Melon, among other crops, is still lagging in genomic resources, limiting the ability to discover new markers in a high-throughput fashion. One of the methods used to search for molecular markers is DNA hybridization to microarrays. Microarray hybridization of DNA from different accessions can reveal differences between them--single-feature polymorphisms (SFPs). These SFPs can be used as markers for breeding purposes, or they can be converted to conventional markers by sequencing. This method has been utilized in a few different plants to discover genetic variation, using Affymetrix arrays that exist for only a few organisms. We applied this approach with some modifications for marker discovery in melon.
In order to broaden the available genetic variation of melon, we developed an ethyl methanesulfon... more In order to broaden the available genetic variation of melon, we developed an ethyl methanesulfonate mutation library in an orange-flesh 'Charentais' type melon line that accumulates β-carotene. One mutagenized M2 family segregated for a novel recessive trait, a yellow-orange fruit flesh ('yofI'). HPLC analysis revealed that 'yofI' accumulates pro-lycopene (tetra-cis-lycopene) as its major fruit pigment. The altered carotenoid composition of 'yofI' is associated with a significant change of the fruit aroma since cleavage of β-carotene yields different apocarotenoids than the cleavage of pro-lycopene. Normally, pro-lycopene is further isomerized by CRTISO (carotenoid isomerase) to yield all-trans-lycopene, which is further cyclized to β-carotene in melon fruit. Cloning and sequencing of 'yofI' CRTISO identified two mRNA sequences which lead to truncated forms of CRTISO. Sequencing of the genomic CRTISO identified an A-T transversion in 'yofI' which leads to a premature STOP codon. The early carotenoid pathway genes were up regulated in yofI fruit causing accumulation of other intermediates such as phytoene and ζ-carotene. Total carotenoid levels are only slightly increased in the mutant. Mutants accumulating pro-lycopene have been reported in both tomato and watermelon fruits, however, this is the first report of a non-lycopene accumulating fruit showing this phenomenon.
Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor "Candidatus Portiera aley... more Whiteflies (Homoptera: Aleyrodidae) are sap-sucking insects that harbor "Candidatus Portiera aleyrodidarum," an obligatory symbiotic bacterium which is housed in a special organ called the bacteriome. These insects are also home for a diverse facultative microbial community which may include Hamiltonella, Arsenophonus, Fritchea, Wolbachia, and Cardinium spp. In this study, the bacteria associated with a B biotype of the sweet potato whitefly Bemisia tabaci were characterized using molecular fingerprinting techniques, and a Rickettsia sp. was detected for the first time in this insect family. Rickettsia sp. distribution, transmission and localization were studied using PCR and fluorescence in situ hybridizations (FISH). Rickettsia was found in all 20 Israeli B. tabaci populations screened but not in all individuals within each population. A FISH analysis of B. tabaci eggs, nymphs, and adults revealed a unique concentration of Rickettsia around the gut and follicle cells, as well as a random distribution in the hemolymph. We postulate that the Rickettsia enters the oocyte together with the bacteriocytes, leaves these symbionthousing cells when the egg is laid, multiplies and spreads throughout the egg during embryogenesis and, subsequently, disperses throughout the body of the hatching nymph, excluding the bacteriomes. Although the role Rickettsia plays in the biology of the whitefly is currently unknown, the vertical transmission on the one hand and the partial within-population infection on the other suggest a phenotype that is advantageous under certain conditions but may be deleterious enough to prevent fixation under others.
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