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Eric Verdin - One of the best experts on this subject based on the ideXlab platform.
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Lavender Decline in France Is Associated with Chronic Infection by Lavender-Specific Strains of “Candidatus Phytoplasma solani”
Applied and environmental microbiology, 2018Co-Authors: Olivier Sémétey, Jonathan Gaudin, Sandrine Eveillard, Jean-luc Danet, Pascal Salar, Sébastien Theil, Marie Fontaine, Michel Krausz, Eric Chaisse, Eric VerdinAbstract:Lavender decline compromises French Lavender production, and preliminary data have suggested the involvement of "Candidatus Phytoplasma solani" in the etiology of the disease. In order to evaluate the epidemiological role of "Ca Phytoplasma solani," a 3-year survey was conducted in southeastern France. "Ca Phytoplasma solani" was detected in 19 to 56% of the declining plants, depending on seasons and cultivars, and its prevalence was correlated with symptom severity. Autumn was more favorable than spring for phytoplasma detection, and "Ca Phytoplasma solani" incidence was higher in Lavandula angustifolia than in Lavandula intermedia hybrids. Detection of the phytoplasma fluctuated over months, supporting the chronicity of infection. Three "Ca Phytoplasma solani" secY genotypes, S17, S16, and S14, were the most prevalent in Lavender fields and were also detected in nurseries, whereas strains detected in surrounding bindweed and wild carrots were mostly of the S1 and S4 genotypes. This suggests that Lavender is the main pathogen reservoir of the epidemic. Adults and nymphs of the planthopper vector Hyalesthes obsoletus were commonly captured in Lavender fields and were shown to harbor mainly the prevalent phytoplasma genotypes detected in Lavenders. The "Ca Phytoplasma solani" genotype S17 was transmitted to Catharanthus roseus periwinkle by naturally infected H. obsoletus Finally, the inventory of the bacterial community of declining Lavenders that tested negative for "Ca Phytoplasma solani" by 16S rRNA deep sequencing ruled out the involvement of other phloem-limited bacterial pathogens.IMPORTANCE The etiology and main pathways for the spread of Lavender decline, an infectious disease affecting French Lavender production since the 1960s, have remained unclear, hampering the development of efficient control strategies. An extensive survey of Lavender fields led to the conclusion that "Candidatus Phytoplasma solani" was chronically infecting declining Lavenders and was associated with large infectious populations of Hyalesthes obsoletus planthoppers living on the crop itself. Lavender appeared to be the main reservoir host for Lavender-specific phytoplasma strains, an unusual feature for this phytoplasma, which usually propagates from reservoir weeds to various economically important crops. These results point out the necessity to protect young Lavender fields from the initial phytoplasma inoculum coming from surrounding Lavender fields or from infected nurseries and to promote agricultural practices that reduce the development of H. obsoletus vector populations.
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Lavender decline in France is associated with chronic infection by Lavender-specific strain of “Candidatus Phytoplasma solani”
Applied and Environmental Microbiology, 2018Co-Authors: Olivier Sémétey, Jonathan Gaudin, Sandrine Eveillard, Jean-luc Danet, Pascal Salar, Sébastien Theil, Marie Fontaine, Michel Krausz, Eric Chaisse, Eric VerdinAbstract:Lavender decline compromises the French Lavender production, and preliminary data have suggested the involvement of “Candidatus Phytoplasma solani” in the etiology of the disease. In order to evaluate “Ca. P. solani” epidemiological role, a three year survey was conducted in Southeastern France. “Ca. P. solani” was detected in 19 to 56 % of the declining plants, depending on seasons and cultivars, and its prevalence was correlated with symptom severity. Autumn was more favorable than spring for phytoplasma detection, and “Ca. P. solani” incidence was higher in Lavandula angustifolia than in L. intermedia hybrids. Detection of the phytoplasma fluctuated over months supporting the chronicity of infection. Three ‘Ca. P. solani" secY genotypes S17, S16 and S14 were the most prevalent in Lavender fields and were also detected in nurseries, whereas strains detected in surrounding bindweed and wild carrots were mostly of the S1 and S4 genotypes. This suggests Lavender is the main pathogen reservoir of the epidemic. Adults and nymphs of the planthopper vector Hyalesthes obsoletus were commonly captured in Lavender fields and were shown to mainly harbor the prevalent phytoplasma genotypes detected in Lavenders. The “Ca. P. solani” genotype S17 was transmitted to Catharanthus roseus periwinkle by naturally infected H. obsoletus. Finally, the inventory of the bacterial community of declining Lavenders that tested negative for "Ca. P. solani" by 16S rRNA deep-sequencing ruled out the involvement of other phloem-limited bacterial pathogens.
Mehdi Jalaliheravi - One of the best experts on this subject based on the ideXlab platform.
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elimination of chromatographic and mass spectrometric problems in gc ms analysis of Lavender essential oil by multivariate curve resolution techniques improving the peak purity assessment by variable size moving window evolving factor analysis
Journal of Chromatography B, 2015Co-Authors: Mehdi Jalaliheravi, Roudabeh Sadat Moazenipourasil, Hassan SereshtiAbstract:Abstract In analysis of complex natural matrices by gas chromatography–mass spectrometry (GC–MS), many disturbing factors such as baseline drift, spectral background, homoscedastic and heteroscedastic noise, peak shape deformation (non-Gaussian peaks), low S/N ratio and co-elution (overlapped and/or embedded peaks) lead the researchers to handle them to serve time, money and experimental efforts. This study aimed to improve the GC–MS analysis of complex natural matrices utilizing multivariate curve resolution (MCR) methods. In addition, to assess the peak purity of the two-dimensional data, a method called variable size moving window-evolving factor analysis (VSMW-EFA) is introduced and examined. The proposed methodology was applied to the GC–MS analysis of Iranian Lavender essential oil, which resulted in extending the number of identified constituents from 56 to 143 components. It was found that the most abundant constituents of the Iranian Lavender essential oil are α-pinene (16.51%), camphor (10.20%), 1,8-cineole (9.50%), bornyl acetate (8.11%) and camphene (6.50%). This indicates that the Iranian type Lavender contains a relatively high percentage of α-pinene. Comparison of different types of Lavender essential oils showed the composition similarity between Iranian and Italian (Sardinia Island) Lavenders .
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elimination of chromatographic and mass spectrometric problems in gc ms analysis of Lavender essential oil by multivariate curve resolution techniques improving the peak purity assessment by variable size moving window evolving factor analysis
Journal of Chromatography B, 2015Co-Authors: Mehdi Jalaliheravi, Roudabeh Sadat Moazenipourasil, Hassan SereshtiAbstract:Abstract In analysis of complex natural matrices by gas chromatography–mass spectrometry (GC–MS), many disturbing factors such as baseline drift, spectral background, homoscedastic and heteroscedastic noise, peak shape deformation (non-Gaussian peaks), low S/N ratio and co-elution (overlapped and/or embedded peaks) lead the researchers to handle them to serve time, money and experimental efforts. This study aimed to improve the GC–MS analysis of complex natural matrices utilizing multivariate curve resolution (MCR) methods. In addition, to assess the peak purity of the two-dimensional data, a method called variable size moving window-evolving factor analysis (VSMW-EFA) is introduced and examined. The proposed methodology was applied to the GC–MS analysis of Iranian Lavender essential oil, which resulted in extending the number of identified constituents from 56 to 143 components. It was found that the most abundant constituents of the Iranian Lavender essential oil are α-pinene (16.51%), camphor (10.20%), 1,8-cineole (9.50%), bornyl acetate (8.11%) and camphene (6.50%). This indicates that the Iranian type Lavender contains a relatively high percentage of α-pinene. Comparison of different types of Lavender essential oils showed the composition similarity between Iranian and Italian (Sardinia Island) Lavenders .
Olivier Sémétey - One of the best experts on this subject based on the ideXlab platform.
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Lavender Decline in France Is Associated with Chronic Infection by Lavender-Specific Strains of “Candidatus Phytoplasma solani”
Applied and environmental microbiology, 2018Co-Authors: Olivier Sémétey, Jonathan Gaudin, Sandrine Eveillard, Jean-luc Danet, Pascal Salar, Sébastien Theil, Marie Fontaine, Michel Krausz, Eric Chaisse, Eric VerdinAbstract:Lavender decline compromises French Lavender production, and preliminary data have suggested the involvement of "Candidatus Phytoplasma solani" in the etiology of the disease. In order to evaluate the epidemiological role of "Ca Phytoplasma solani," a 3-year survey was conducted in southeastern France. "Ca Phytoplasma solani" was detected in 19 to 56% of the declining plants, depending on seasons and cultivars, and its prevalence was correlated with symptom severity. Autumn was more favorable than spring for phytoplasma detection, and "Ca Phytoplasma solani" incidence was higher in Lavandula angustifolia than in Lavandula intermedia hybrids. Detection of the phytoplasma fluctuated over months, supporting the chronicity of infection. Three "Ca Phytoplasma solani" secY genotypes, S17, S16, and S14, were the most prevalent in Lavender fields and were also detected in nurseries, whereas strains detected in surrounding bindweed and wild carrots were mostly of the S1 and S4 genotypes. This suggests that Lavender is the main pathogen reservoir of the epidemic. Adults and nymphs of the planthopper vector Hyalesthes obsoletus were commonly captured in Lavender fields and were shown to harbor mainly the prevalent phytoplasma genotypes detected in Lavenders. The "Ca Phytoplasma solani" genotype S17 was transmitted to Catharanthus roseus periwinkle by naturally infected H. obsoletus Finally, the inventory of the bacterial community of declining Lavenders that tested negative for "Ca Phytoplasma solani" by 16S rRNA deep sequencing ruled out the involvement of other phloem-limited bacterial pathogens.IMPORTANCE The etiology and main pathways for the spread of Lavender decline, an infectious disease affecting French Lavender production since the 1960s, have remained unclear, hampering the development of efficient control strategies. An extensive survey of Lavender fields led to the conclusion that "Candidatus Phytoplasma solani" was chronically infecting declining Lavenders and was associated with large infectious populations of Hyalesthes obsoletus planthoppers living on the crop itself. Lavender appeared to be the main reservoir host for Lavender-specific phytoplasma strains, an unusual feature for this phytoplasma, which usually propagates from reservoir weeds to various economically important crops. These results point out the necessity to protect young Lavender fields from the initial phytoplasma inoculum coming from surrounding Lavender fields or from infected nurseries and to promote agricultural practices that reduce the development of H. obsoletus vector populations.
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Lavender decline in France is associated with chronic infection by Lavender-specific strain of “Candidatus Phytoplasma solani”
Applied and Environmental Microbiology, 2018Co-Authors: Olivier Sémétey, Jonathan Gaudin, Sandrine Eveillard, Jean-luc Danet, Pascal Salar, Sébastien Theil, Marie Fontaine, Michel Krausz, Eric Chaisse, Eric VerdinAbstract:Lavender decline compromises the French Lavender production, and preliminary data have suggested the involvement of “Candidatus Phytoplasma solani” in the etiology of the disease. In order to evaluate “Ca. P. solani” epidemiological role, a three year survey was conducted in Southeastern France. “Ca. P. solani” was detected in 19 to 56 % of the declining plants, depending on seasons and cultivars, and its prevalence was correlated with symptom severity. Autumn was more favorable than spring for phytoplasma detection, and “Ca. P. solani” incidence was higher in Lavandula angustifolia than in L. intermedia hybrids. Detection of the phytoplasma fluctuated over months supporting the chronicity of infection. Three ‘Ca. P. solani" secY genotypes S17, S16 and S14 were the most prevalent in Lavender fields and were also detected in nurseries, whereas strains detected in surrounding bindweed and wild carrots were mostly of the S1 and S4 genotypes. This suggests Lavender is the main pathogen reservoir of the epidemic. Adults and nymphs of the planthopper vector Hyalesthes obsoletus were commonly captured in Lavender fields and were shown to mainly harbor the prevalent phytoplasma genotypes detected in Lavenders. The “Ca. P. solani” genotype S17 was transmitted to Catharanthus roseus periwinkle by naturally infected H. obsoletus. Finally, the inventory of the bacterial community of declining Lavenders that tested negative for "Ca. P. solani" by 16S rRNA deep-sequencing ruled out the involvement of other phloem-limited bacterial pathogens.
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Phytoplasma titer in diseased Lavender is not correlated to Lavender tolerance to stolbur phytoplasma
2011Co-Authors: Jonathan Gaudin, Olivier Sémétey, Xavier Foissac, Sandrine EveillardAbstract:Yellow decline of Lavender is associated with stolbur phytoplasma. It is an economically important disease in south-eastern France, and there is no curative control method. In the past few years, susceptible and tolerant Lavenders (Lavandula spp.) or lavandins (Lavandula latifolia x lavandula angustifolia) were proposed as disease management strategy to growers. However, the bases of tolerance were unknown. In order to establish these possible bases, we compared the titers of stolbur phytoplasma in the leaves and shoots of different Lavenders and lavandins, either sensitive or tolerant. Results showed that symptom severity was not correlated to the tolerance status of all cultivars tested, and that symptom severity was not correlated to the phytoplasma titer.
Soheil S. Mahmoud - One of the best experts on this subject based on the ideXlab platform.
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cloning and functional characterization of a floral repressor gene from lavandula angustifolia
Planta, 2020Co-Authors: Rebecca Wells, Ayelign M. Adal, Lina Bauer, Elaheh Najafianashrafi, Soheil S. MahmoudAbstract:MAIN CONCLUSION Using RNA-Seq, we identified genes involved in floral development in Lavenders and functionally characterized the floral repressor LaSVP. The molecular aspects of flower initiation and development have not been adequately investigated in Lavender (Lavandula). In order to identify genes that control these processes, we employed RNA-Seq to obtain sequence information for transcripts originating from the vegetative shoot apical meristem (SAM) and developing inflorescence tissues of Lavandula angustifolia and Lavandula × intermedia plants, and assemble a comprehensive transcriptome of 105,294 contigs. Homology-based annotation provided gene ontology terms for the majority of transcripts, including over 100 genes homologous to those that control flower initiation and organ identity in Arabidopsis thaliana. Expression analysis revealed that most of these genes are differentially expressed during flower development. For example, LaSVP, a homolog of the floral repressor SHORT VEGETATIVE PHASE (SVP), was strongly expressed in vegetative SAM compared to developing flowers, implicating its potential involvement in flowering repression in Lavender. To investigate LaSVP further, we constitutively expressed the gene in transformed A. thaliana plants, evaluating its effects on flower initiation and morphology. Expression of the LaSVP in A. thaliana delayed flowering and affected flower organ identity in a dosage-dependent manner. Two of the highest expressing lines produced sepals instead of petals and were sterile as they failed to develop proper seed pods. This study provides the foundation for future investigations aimed at elucidating flower initiation and development in Lavender.
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De novo sequencing of the Lavandula angustifolia genome reveals highly duplicated and optimized features for essential oil production
Planta, 2019Co-Authors: Radesh P N Malli, Ayelign M. Adal, Lukman S Sarker, Ping Liang, Soheil S. MahmoudAbstract:Main conclusion The first draft genome for a member of the genus Lavandula is described. This 870 Mbp genome assembly is composed of over 688 Mbp of non-gap sequences comprising 62,141 protein-coding genes. Lavenders ( Lavandula : Lamiaceae ) are economically important plants widely grown around the world for their essential oils (EOs), which contribute to the cosmetic, personal hygiene, and pharmaceutical industries. To better understand the genetic mechanisms involved in EO production, identify genes involved in important biological processes, and find genetic markers for plant breeding, we generated the first de novo draft genome assembly for L. angustifolia (Maillette). This high-quality draft reveals a moderately repeated (> 48% repeated elements) 870 Mbp genome, composed of over 688 Mbp of non-gap sequences in 84,291 scaffolds with an N50 value of 96,735 bp. The genome contains 62,141 protein-coding genes and 2003 RNA-coding genes, with a large proportion of genes showing duplications, possibly reflecting past genome polyploidization. The draft genome contains full-length coding sequences for all genes involved in both cytosolic and plastidial pathways of isoprenoid metabolism, and all terpene synthase genes previously described from Lavenders. Of particular interest is the observation that the genome contains a high copy number (14 and 7, respectively) of DXS (1-deoxyxylulose-5-phosphate synthase) and HDR (4-hydroxy-3-methylbut-2-enyl diphosphate reductase) genes, encoding the two known regulatory steps in the plastidial isoprenoid biosynthetic pathway. The latter generates precursors for the production of monoterpenes, the most abundant essential oil constituents in Lavender. Furthermore, the draft genome contains a variety of monoterpene synthase genes, underlining the production of several monoterpene essential oil constituents in Lavender. Taken together, these findings indicate that the genome of L. angustifolia is highly duplicated and optimized for essential oil production.
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rna seq in the discovery of a sparsely expressed scent determining monoterpene synthase in Lavender lavandula
Planta, 2019Co-Authors: Ayelign M. Adal, Lukman S Sarker, Radesh P N Malli, Ping Liang, Soheil S. MahmoudAbstract:Using RNA-Seq, we cloned and characterized a unique monoterpene synthase responsible for the formation of a scent-determining S-linalool constituent of Lavender oils from Lavandula × intermedia. Several species of Lavandula produce essential oils (EOs) consisting mainly of monoterpenes including linalool, one of the most abundant and scent-determining oil constituents. Although R-linalool dominates the EOs of Lavenders, varying amounts (depending on the species) of the S-linalool enantiomer can also be found in these plants. Despite its relatively low abundance, S-linalool contributes a sweet, pleasant scent and is an important constituent of Lavender EOs. While several terpene synthase genes including R-linalool synthase have been cloned from Lavenders many important terpene synthases including S-linalool synthase have not been described from these plants. In this study, we employed RNA-Seq and other complementary sequencing data to clone and functionally characterize the sparsely expressed S-linalool synthase cDNA (LiS-LINS) from Lavandula × intermedia. Recombinant LiS-LINS catalyzed the conversion of the universal monoterpene precursor geranyl diphosphate to S-linalool as the sole product. Intriguingly, LiS-LINS exhibited very low (~ 30%) sequence similarity to other Lavandula terpene synthases, including R-linalool synthase. However, the predicted 3D structure of this protein, including the composition and arrangement of amino acids at the active site, is highly homologous to known terpene synthase proteins. LiS-LINS transcripts were detected in flowers, but were much less abundant than those corresponding to LiR-LINS, paralleling enantiomeric composition of linalool in L. × intermedia oils. These data indicate that production of S-linalool is at least partially controlled at the level of transcription from LiS-LINS. The cloned LiS-LINS cDNA may be used to enhance oil composition in Lavenders and other plants through metabolic engineering.
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A Lavender ABC transporter confers resistance to monoterpene toxicity in yeast
Planta, 2018Co-Authors: Zerihun A. Demissie, Mike Tarnowycz, Ayelign M. Adal, Lukman S Sarker, Soheil S. MahmoudAbstract:Functional expression of a multidrug resistance-type ABC transporter from Lavandulaangustifolia improved yeast resistance to geraniol, a monoterpene constituent of Lavender essential oil. Plant ATP-binding cassette (ABC) transporters are a large family of membrane proteins involved in active and selective transport of structurally diverse compounds. In this study, we functionally evaluated LaABCB1, a multidrug resistance (MDR)-type ABC transporter strongly expressed in the secretory cells of Lavender glandular trichomes, where monoterpene essential oil constituents are synthesized and secreted. We used LaABCB1 to complement a yeast knockout mutant in which 16 ABC transporters were deleted. Expression of LaABCB1 enhanced tolerance of yeast mutants to geraniol, a key constituent of essential oils in Lavenders and numerous other plants. Our findings suggest a role for the MDR-type ABC transporters in the toxicity tolerance of at least certain essential oil constituents in Lavender oil glands.
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chapter 57 Lavender lavandula angustifolia oils
Essential Oils in Food Preservation Flavor and Safety, 2016Co-Authors: Lauren A E Erland, Soheil S. MahmoudAbstract:Lavenders are popular aromatic plants in the Lamiaceae family native to the Mediterranean region. Aqueous extracts, essential oils, and dried parts of these plants have long been used in cosmetics, hygiene products, and traditional medicines. In addition, they are used as food additives due to their pleasant flavor and aroma, and their antibacterial, antifungal, insect repellent, insecticidal, and antioxidant properties. With increasing concerns about loss of effectiveness and safety of commercial antibiotics, antifungals, insecticides, and preservatives, botanical products, including Lavenders, are coming to the forefront. In this review, the current and potential applications of Lavender essential oil in the food sciences are discussed.
Sonia Collin - One of the best experts on this subject based on the ideXlab platform.
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Floral quality and discrimination of Lavandula stoechas, Lavandula angustifolia, and Lavandula angustifolia×latifolia honeys
Food Chemistry, 2002Co-Authors: Christine Guyot-declerck, Sarah Renson, Amina Bouseta, Sonia CollinAbstract:Portuguese Lavender honeys are generated from the nectar of Lavandula stoechas, whereas French Lavender honeys are exclusively derived from Lavandula angustifolia, Lavandula latifolia, or hybrids of these two species. In the framework of the floral origin authentication of such honeys, volatile compounds from L. stoechas, L. angustifolia, and L. angustifolia×latifolia unifloral honeys were investigated. The aromatic profiles of French and Portuguese Lavender honey samples showed major qualitative and quantitative differences, but no volatile compound is characteristic of L. stoechas honeys only. As expected, n-hexanal, n-heptanal, phenylacetaldehyde, and n-hexanol, previously proposed to authenticate French Lavender honeys, were found at concentrations far above the published discrimination thresholds. Coumarin, previously proposed to characterize French Lavender honeys, emerges here rather as an indicator of the freshness of Lavender honey, being mainly released from glycosides during storage. Lastly, L. angustifolia honeys were distinguishable from hybrid-derived samples by their lower phenylacetaldehyde and higher heptanoic acid content.
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floral quality and discrimination of lavandula stoechas lavandula angustifolia and lavandula angustifolia latifolia honeys
Food Chemistry, 2002Co-Authors: Christine Guyotdeclerck, Sarah Renson, Amina Bouseta, Sonia CollinAbstract:Portuguese Lavender honeys are generated from the nectar of Lavandula stoechas, whereas French Lavender honeys are exclusively derived from Lavandula angustifolia, Lavandula latifolia, or hybrids of these two species. In the framework of the floral origin authentication of such honeys, volatile compounds from L. stoechas, L. angustifolia, and L. angustifolia×latifolia unifloral honeys were investigated. The aromatic profiles of French and Portuguese Lavender honey samples showed major qualitative and quantitative differences, but no volatile compound is characteristic of L. stoechas honeys only. As expected, n-hexanal, n-heptanal, phenylacetaldehyde, and n-hexanol, previously proposed to authenticate French Lavender honeys, were found at concentrations far above the published discrimination thresholds. Coumarin, previously proposed to characterize French Lavender honeys, emerges here rather as an indicator of the freshness of Lavender honey, being mainly released from glycosides during storage. Lastly, L. angustifolia honeys were distinguishable from hybrid-derived samples by their lower phenylacetaldehyde and higher heptanoic acid content.