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Dina A St Clair - One of the best experts on this subject based on the ideXlab platform.

  • high resolution mapping of a major effect qtl from wild tomato Solanum Habrochaites that influences water relations under root chilling
    Theoretical and Applied Genetics, 2015
    Co-Authors: Erin M Arms, Arnold J Bloom, Dina A St Clair
    Abstract:

    Key message QTLstm9controlling rapid-onset water stress tolerance inS. Habrochaiteswas high-resolution mapped to a chromosome 9 region that contains genes associated with abiotic stress tolerances.

  • multiple qtl for horticultural traits and quantitative resistance to phytophthora infestans linked on Solanum Habrochaites chromosome 11
    G3: Genes Genomes Genetics, 2015
    Co-Authors: Erron J Haggard, Emily B Johnson, Dina A St Clair
    Abstract:

    Previously, a Phytophthora infestans resistance QTL from Solanum Habrochaites chromosome 11 was introgressed into cultivated tomato (S. lycopersicum). Fine mapping of this resistance QTL using near-isogenic lines (NILs) revealed some co-located QTL with undesirable effects on plant size, canopy density, and fruit size traits. Subsequently, higher-resolution mapping with sub-NILs detected multiple P. infestans resistance QTL within this 9.4-cM region of chromosome 11. In our present study, these same sub-NILs were also evaluated for 17 horticultural traits, including yield, maturity, fruit size and shape, fruit quality, and plant architecture traits in replicated field experiments over 2 years. The horticultural trait QTL originally detected by fine mapping each fractionated into two or more QTL at higher resolution. A total of 34 QTL were detected across all traits, with 14% exhibiting significant QTL × environment interactions (QTL × E). QTL for many traits were co-located, suggesting either pleiotropic effects or tight linkage among genes controlling these traits. Recombination in the pericentromeric region of the introgression between markers TG147 and At4g10050 was suppressed to approximately 29.7 Mbp per cM, relative to the genomewide average of 750 kbp per cM. The genetic architecture of many of the horticultural and P. infestans resistance traits that mapped within this chromosome 11 S. Habrochaites region is complex. Complicating factors included fractionation of QTL, pleiotropy or tight linkage of QTL for multiple traits, pericentromeric chromosomal location(s), and/or QTL × E. High-resolution mapping of QTL in this region would be needed to determine which specific target QTL could be useful in breeding cultivated tomato.

  • linkage relationships among multiple qtl for horticultural traits and late blight p infestans resistance on chromosome 5 introgressed from wild tomato Solanum Habrochaites
    G3: Genes Genomes Genetics, 2013
    Co-Authors: Erron J Haggard, Emily B Johnson, Dina A St Clair
    Abstract:

    When the allele of a wild species at a quantitative trait locus (QTL) conferring a desirable trait is introduced into cultivated species, undesirable effects on other traits may occur. These negative phenotypic effects may result from the presence of wild alleles at other closely linked loci that are transferred along with the desired QTL allele (i.e., linkage drag) and/or from pleiotropic effects of the desired allele. Previously, a QTL for resistance to Phytophthora infestans on chromosome 5 of Solanum Habrochaites was mapped and introgressed into cultivated tomato (S. lycopersicum). Near-isogenic lines (NILs) were generated and used for fine-mapping of this resistance QTL, which revealed coincident or linked QTL with undesirable effects on yield, maturity, fruit size, and plant architecture traits. Subsequent higher-resolution mapping with chromosome 5 sub-NILs revealed the presence of multiple P. infestans resistance QTL within this 12.3 cM region. In our present study, these sub-NILs were also evaluated for 17 horticultural traits, including yield, maturity, fruit size and shape, fruit quality, and plant architecture traits in replicated field experiments over the course of two years. Each previously detected single horticultural trait QTL fractionated into two or more QTL. A total of 41 QTL were detected across all traits, with ∼30% exhibiting significant QTL × environment interactions. Colocation of QTL for multiple traits suggests either pleiotropy or tightly linked genes control these traits. The complex genetic architecture of horticultural and P. infestans resistance trait QTL within this S. Habrochaites region of chromosome 5 presents challenges and opportunities for breeding efforts in cultivated tomato.

Daniel A Jones - One of the best experts on this subject based on the ideXlab platform.

  • relative mass defect filtering of mass spectra a path to discovery of plant specialized metabolites
    Plant Physiology, 2015
    Co-Authors: E Prabodha A Ekanayaka, Mary Dawn Celiz, Daniel A Jones
    Abstract:

    The rapid identification of novel plant metabolites and assignments of newly discovered substances to natural product classes present the main bottlenecks to defining plant specialized phenotypes. Although mass spectrometry provides powerful support for metabolite discovery by measuring molecular masses, ambiguities in elemental formulas often fail to reveal the biosynthetic origins of specialized metabolites detected using liquid chromatography-mass spectrometry. A promising approach for mining liquid chromatography-mass spectrometry metabolite profiling data for specific metabolite classes is achieved by calculating relative mass defects (RMDs) from molecular and fragment ions. This strategy enabled the rapid recognition of an extensive range of terpenoid metabolites in complex plant tissue extracts and is independent of retention time, abundance, and elemental formula. Using RMD filtering and tandem mass spectrometry data analysis, 24 novel elemental formulas corresponding to glycosylated sesquiterpenoid metabolites were identified in extracts of the wild tomato Solanum Habrochaites LA1777 trichomes. Extensive isomerism was revealed by ultra-high-performance liquid chromatography, leading to evidence of more than 200 distinct sesquiterpenoid metabolites. RMD filtering led to the recognition of the presence of glycosides of two unusual sesquiterpenoid cores that bear limited similarity to known sesquiterpenes in the genus Solanum. In addition, RMD filtering is readily applied to existing metabolomics databases and correctly classified the annotated terpenoid metabolites in the public metabolome database for Catharanthus roseus.

  • functionally divergent alleles and duplicated loci encoding an acyltransferase contribute to acylsugar metabolite diversity in Solanum trichomes
    The Plant Cell, 2015
    Co-Authors: Anthony L Schilmiller, Banibrata Ghosh, Gaurav D Moghe, Jing Ning, Daniel A Jones
    Abstract:

    Glandular trichomes from tomato (Solanum lycopersicum) and other species in the Solanaceae produce and secrete a mixture of O-acylsugars (aliphatic esters of sucrose and glucose) that contribute to insect defense. Despite their phylogenetic distribution and diversity, relatively little is known about how these specialized metabolites are synthesized. Mass spectrometric profiling of acylsugars in the S. lycopersicum x Solanum pennellii introgression lines identified a chromosome 11 locus containing a cluster of BAHD acyltransferases with one gene (named Sl-ASAT3) expressed in tip cells of type I trichomes where acylsugars are made. Sl-ASAT3 was shown to encode an acyl-CoA-dependent acyltransferase that catalyzes the transfer of short (four to five carbons) branched acyl chains to the furanose ring of di-acylsucrose acceptors to produce tri-acylsucroses, which can be further acetylated by Sl-ASAT4 (previously Sl-AT2). Among the wild tomatoes, diversity in furanose ring acyl chains on acylsucroses was most striking in Solanum Habrochaites. S. Habrochaites accessions from Ecuador and northern Peru produced acylsucroses with short (≤C5) or no acyl chains on the furanose ring. Accessions from central and southern Peru had the ability to add short or long (up to C12) acyl chains to the furanose ring. Multiple ASAT3-like sequences were found in most accessions, and their in vitro activities correlated with observed geographical diversity in acylsugar profiles.

  • sesquiterpenoid glycosides from glandular trichomes of the wild tomato relative Solanum Habrochaites
    Phytochemistry, 2014
    Co-Authors: E Prabodha A Ekanayaka, Daniel A Jones
    Abstract:

    Profiles of terpenoid glycoside metabolites in glandular trichomes of Solanum Habrochaites LA1777 leaves were generated using ultrahigh performance liquid chromatography/time-of-flight mass spectrometry with multiplexing of non-selective collision-induced dissociation (CID). Profiling data suggested a diverse group of 52 sesquiterpenoid glycosides, and fragment ions observed in both non-selective CID mass spectra and true tandem mass spectrometry (MS/MS) product ion spectra documented variation in extent of glycosylation and the presence of malonate or acetate esters. Up to 10 isomers were detected for some metabolites. Malonate and acetate esters of three sesquiterpene diol glucosides and one unmodified diglucoside were purified using reversed phase semipreparative HPLC and analyzed and identified using 1D and 2D NMR and mass spectrometry. All four of the isolated products were glucosides of campheranane-2,12-diol.

  • comparative structural profiling of trichome specialized metabolites in tomato Solanum lycopersicum and s Habrochaites acylsugar profiles revealed by uhplc ms and nmr
    Metabolomics, 2014
    Co-Authors: Banibrata Ghosh, Thomas C Westbrook, Daniel A Jones
    Abstract:

    Many plants accumulate large quantities of specialized metabolites in secretory glandular trichomes (SGTs), which are specialized epidermal cells. In the genus Solanum, SGTs store a diverse collection of glucose and sucrose esters. Profiling of extracts from two accessions (LA1777 and LA1392) of Solanum Habrochaites using ultra-high performance liquid chromatography–mass spectrometry (UHPLC/MS) revealed wide acylsugar diversity, with up to 11 isomers annotated for each individual elemental formula. These isomers arise from differences in ester chain lengths and their positions of substitution or branching. Since fragment ion masses were not sufficient to distinguish all isomers, 24 acylsucroses were purified from S. Habrochaites accessions and cultivated tomato (Solanum lycopersicum M82) and characterized using NMR spectroscopy. Two-dimensional NMR spectra yielded assignments of positions of substitution of specific acyl groups, and locations of branching. The range of substitution was wider than reported earlier, and in contrast to previous reports, tetra- and penta-acylsucroses were substituted at position 2 with acyl groups other than acetate. Because UHPLC/MS fails to yield sufficient information about structure diversity, and quantitative NMR of acylsugar mixtures is confounded by structural redundancy, the strategic combination of NMR and UHPLC/MS provides a powerful approach for profiling a class of metabolites with great structural diversity across genotypes.

  • striking natural diversity in glandular trichome acylsugar composition is shaped by variation at the acyltransferase2 locus in the wild tomato Solanum Habrochaites
    Plant Physiology, 2012
    Co-Authors: Jeongwoon Kim, Daniel A Jones, Eliana Gonzalesvigil, Kiyoon Kang, Feng Shi, Cornelius S Barry
    Abstract:

    Acylsugars are polyesters of short- to medium-length acyl chains on sucrose or glucose backbones that are produced in secretory glandular trichomes of many solanaceous plants, including cultivated tomato (Solanum lycopersicum). Despite their roles in biotic stress adaptation and their wide taxonomic distribution, there is relatively little information about the diversity of these compounds and the genes responsible for their biosynthesis. In this study, acylsugar diversity was assessed for 80 accessions of the wild tomato species Solanum Habrochaites from throughout the Andes Mountains. Trichome metabolites were analyzed by liquid chromatography-time of flight-mass spectrometry, revealing the presence of at least 34 structurally diverse acylsucroses and two acylglucoses. Distinct phenotypic classes were discovered that varied based on the presence of glucose or sucrose, the numbers and lengths of acyl chains, and the relative total amounts of acylsugars. The presence or absence of an acetyl chain on the acylsucrose hexose ring caused clustering of the accessions into two main groups. Analysis of the Acyltransferase2 gene (the apparent ortholog of Solyc01g105580) revealed differences in enzyme activity and gene expression correlated with polymorphism in S. Habrochaites accessions that varied in acylsucrose acetylation. These results are consistent with the hypothesis that glandular trichome acylsugar acetylation is under selective pressure in some populations of S. Habrochaites and that the gene mutates to inactivity in the absence of selection.

Alain Tissier - One of the best experts on this subject based on the ideXlab platform.

  • two novel 7 epi zingiberene derivatives with biological activity from Solanum Habrochaites are produced by a single cytochrome p450 monooxygenase
    bioRxiv, 2020
    Co-Authors: Sebastian Zabel, Benedikt Athmer, Petra M. Bleeker, Wolfgang Brandt, Andrea Porzel, Ruy Kortbeek, Alain Tissier
    Abstract:

    Abstract Secretions from glandular trichomes potentially protect the plant against a variety of aggressors. In the tomato genus, wild species constitute a rich source of chemical diversity produced at the leaf surface by glandular trichomes. Previously, 7-epi-zingiberene produced in several accessions of Solanum Habrochaites was found to confer resistance to whiteflies (Bemisia tabaci) and other insect pests. Here, we identify two derivatives of 7-epi-zingiberene from S. Habrochaites that had not been reported as yet. We identified them as 9-hydroxy-zingiberene and 9-hydroxy-10,11-epoxyzingiberene. Using a combination of genetics and transcriptomics we identified a single cytochrome P450 oxygenase, ShCYP71D184 that carries out two successive oxidations to generate the two sesquiterpenoids. Bioactivity assays showed that only 9-hydroxy-10,11-epoxyzingiberene exhibits substantial toxicity against B. tabaci. In addition, both 9-hydroxy-zingiberene and 9-hydroxy-10,11-epoxyzingiberene display substantial growth inhibitory activities against a range of microorganisms, including Bacillus subtilis, Phytophtora infestans and Botrytis cinerea. Our work shows that trichome secretions from wild tomato species can provide protection against a wide variety of organisms. In addition, the availability of the genes encoding the enzymes for the pathway of 7-epi-zingiberene derivatives makes it possible to introduce this trait in cultivated tomato by precision breeding.

  • qtl mapping of the shape of type vi glandular trichomes in tomato
    Frontiers in Plant Science, 2018
    Co-Authors: Stefan Bennewitz, Nick Bergau, Alain Tissier
    Abstract:

    Glandular trichomes contribute to the high resistance of wild tomato species against insect pests not only thanks to the metabolites they produce but also because of morphological and developmental features which support the high production of these defense compounds. In Solanum Habrochaites, type VI trichomes have a distinct spherical shape and a large intercellular storage cavity where metabolites can accumulate and are released upon breaking off of the glandular cells. In contrast, the type VI trichomes of S. lycopersicum have a four-leaf clover shape corresponding to the four glandular cells and a small internal cavity with limited capacity for storage of compounds. To better characterize the genetic factors underlying these trichome morphological differences we created a back-cross population of 116 individuals between S. Habrochaites LA1777 and S. lycopersicum var. cerasiformae WVa106. A trichome score that reflects the shape of the type VI trichomes allowing the quantification of this trait was designed. The scores were distributed normally across the population, which was mapped with a total of 192 markers. This resulted in the identification of 6 QTLs on chromosomes I, VII, VII and XI. The QTL on chromosome I with the highest LOD score was confirmed and narrowed down to a 500 gene interval in an advanced population derived from one of the back-cross lines. Our results provide the foundation for the genetic dissection of type VI trichome morphology and the introgression of these trichome traits into cultivated tomato lines for increased insect resistance.

  • multi omics of tomato glandular trichomes reveals distinct features of central carbon metabolism supporting high productivity of specialized metabolites
    The Plant Cell, 2017
    Co-Authors: Gerd Ulrich Balcke, Stefan Bennewitz, Nick Bergau, Benedikt Athmer, Petra Majovsky, Wolfgang Hoehenwarter, Anja Henning, Jose M Jimenezgomez, Alain Tissier
    Abstract:

    Glandular trichomes are metabolic cell factories with the capacity to produce large quantities of secondary metabolites. Little is known about the connection between central carbon metabolism and metabolic productivity for secondary metabolites in glandular trichomes. To address this gap in our knowledge, we performed comparative metabolomics, transcriptomics, proteomics and 13C-labeling of type VI glandular trichomes and leaves from a cultivated (Solanum lycopersicum LA4024) and a wild (Solanum Habrochaites LA1777) tomato accession. Specific features of glandular trichomes that drive the formation of secondary metabolites could be identified. Tomato type VI trichomes are photosynthetic but acquire their carbon essentially from leaf sucrose. The energy and reducing power from photosynthesis are used to support the biosynthesis of secondary metabolites, while the comparatively reduced Calvin-Benson-Bassham cycle activity may be involved in recycling metabolic CO2. Glandular trichomes cope with oxidative stress by producing high levels of polyunsaturated fatty acids, oxylipins, and glutathione. Finally, distinct mechanisms are present in glandular trichomes to increase the supply of precursors for the isoprenoid pathways. Particularly, the citrate-malate shuttle supplies cytosolic acetyl CoA and plastidic glycolysis and malic enzyme support the formation of plastidic pyruvate. A model is proposed on how glandular trichomes achieve high metabolic productivity.

  • autofluorescence as a signal to sort developing glandular trichomes by flow cytometry
    Frontiers in Plant Science, 2016
    Co-Authors: Nick Bergau, Anja Henning, Gerd Ulrich Balcke, Alexander Navarette Santos, Alain Tissier
    Abstract:

    The industrial relevance of a number of metabolites produced in plant glandular trichomes has spurred research on these specialized organs for a number of years. Most of the research however, has focused on the elucidation of secondary metabolite pathways and comparatively little has been undertaken on the development and differentiation of glandular trichomes. One way to gain insight into these developmental processes is to generate stage-specific transcriptome and metabolome data. The difficulty for this resides in the isolation of early stages of development of the glandular trichomes. Here we describe a method for the separation and isolation of intact young and mature type VI trichomes from the wild tomato species Solanum Habrochaites. The final and key step of the method uses cell sorting based on distinct autofluorescence signals of the young and mature trichomes. We demonstrate that sorting by flow cytometry allows recovering pure fractions of young and mature trichomes. Furthermore, we show that the sorted trichomes can be used for transcript and metabolite analyses. Because, many plant tissues or cells have distinct autofluorescence components, the principles of this method can be generally applicable for the isolation of specific cell types without prior labeling.

  • Discovering Regulated Metabolite Families in Untargeted Metabolomics Studies
    2016
    Co-Authors: Hendrik Treutler, Alain Tissier, Andrea Porzel, Hiroshi Tsugawa, Karin Gorzolka, Steffen Neumann, Gerd Ulrich Balcke
    Abstract:

    The identification of metabolites by mass spectrometry constitutes a major bottleneck which considerably limits the throughput of metabolomics studies in biomedical or plant research. Here, we present a novel approach to analyze metabolomics data from untargeted, data-independent LC-MS/MS measurements. By integrated analysis of MS1 abundances and MS/MS spectra, the identification of regulated metabolite families is achieved. This approach offers a global view on metabolic regulation in comparative metabolomics. We implemented our approach in the web application “MetFamily”, which is freely available at http://msbi.ipb-halle.de/MetFamily/. MetFamily provides a dynamic link between the patterns based on MS1-signal intensity and the corresponding structural similarity at the MS/MS level. Structurally related metabolites are annotated as metabolite families based on a hierarchical cluster analysis of measured MS/MS spectra. Joint examination with principal component analysis of MS1 patterns, where this annotation is preserved in the loadings, facilitates the interpretation of comparative metabolomics data at the level of metabolite families. As a proof of concept, we identified two trichome-specific metabolite families from wild-type tomato Solanum Habrochaites LA1777 in a fully unsupervised manner and validated our findings based on earlier publications and with NMR

Eran Pichersky - One of the best experts on this subject based on the ideXlab platform.

  • determination of residues responsible for substrate and product specificity of Solanum Habrochaites short chain cis prenyltransferases
    Plant Physiology, 2014
    Co-Authors: Jin Ho Kang, Yuki Matsuba, Eran Pichersky, Eliana Gonzalesvigil, Cornelius S Barry
    Abstract:

    Isoprenoids are diverse compounds that have their biosynthetic origin in the initial condensation of isopentenyl diphosphate and dimethylallyl diphosphate to form C10 prenyl diphosphates that can be elongated by the addition of subsequent isopentenyl diphosphate units. These reactions are catalyzed by either cis-prenyltransferases (CPTs) or trans-prenyltransferases. The synthesis of volatile terpenes in plants typically proceeds through either geranyl diphosphate (C10) or trans-farnesyl diphosphate (C15), to yield monoterpenes and sesquiterpenes, respectively. However, terpene biosynthesis in glandular trichomes of tomato (Solanum lycopersicum) and related wild relatives also occurs via the cis-substrates neryl diphosphate (NPP) and 2Z,6Z-farnesyl diphosphate (Z,Z-FPP). NPP and Z,Z-FPP are synthesized by neryl diphosphate synthase1 (NDPS1) and Z,Z-farnesyl diphosphate synthase (zFPS), which are encoded by the orthologous CPT1 locus in tomato and Solanum Habrochaites, respectively. In this study, comparative sequence analysis of NDPS1 and zFPS enzymes from S. Habrochaites accessions that synthesize either monoterpenes or sesquiterpenes was performed to identify amino acid residues that correlate with the ability to synthesize NPP or Z,Z-FPP. Subsequent structural modeling, coupled with site-directed mutagenesis, highlighted the importance of four amino acids located within conserved domain II of CPT enzymes that form part of the second α-helix, for determining substrate and product specificity of these enzymes. In particular, the relative positioning of aromatic amino acid residues at positions 100 and 107 determines the ability of these enzymes to synthesize NPP or Z,Z-FPP. This study provides insight into the biochemical evolution of terpene biosynthesis in the glandular trichomes of Solanum species.

  • Characterization of a flavonol 3-O-methyltransferase in the trichomes of the wild tomato species Solanum Habrochaites
    Planta, 2012
    Co-Authors: Adam Schmidt, Chao Li, A. Daniel Jones, Eran Pichersky
    Abstract:

    The glandular trichomes of the wild tomato species Solanum Habrochaites accumulate the polymethylated flavonol aglycones, 3,7,3′- O -methyl myricetin, 3,7,3′,5′- O -methyl myricetin, and 3,7,3′,4′,5′- O -methyl myricetin. Partially methylated flavonol aglycones and partially methylated flavonol glycones containing a methyl group at the 3 position have been previously reported from a variety of plants. The 3- O -methyltransferase (3-OMT) activity has been previously partially purified from plants, but a gene transcript encoding an enzyme capable of methylating flavonols at the 3 position has not yet been identified, nor have been such proteins purified and characterized. We previously identified two gene transcripts expressed in the glandular trichomes of S. Habrochaites and showed that they encode enzymes capable of methylating myricetin at the 3′ and 5′ and the 7 and 4′ positions, respectively. Here we report the identification of gene transcripts expressed in S. lycopersicum (cultivated tomato) and in S. Habrochaites glandular trichomes that encode enzymes capable of methylating myricetin, and its partially methylated derivatives exclusively at the 3 position. The S. Habrochaites gene transcript is preferentially expressed in the glandular trichomes and it encodes a protein with high similarity to the S. Habrochaites , 3′/5′ O -methyltransferase which is also present in glandular trichomes. Phylogenic analysis suggests that the 3-OMT activity has probably evolved from an ancestral 3′/5′ methyltransferase activity. The discovery and characterization of 3-OMT provides a more complete picture of the series of reactions leading to highly methylated myricetin compounds in S. Habrochaites glandular trichomes.

  • RNA-seq discovery, functional characterization, and comparison of sesquiterpene synthases from Solanum lycopersicum and Solanum Habrochaites trichomes
    Plant Molecular Biology, 2011
    Co-Authors: Petra M. Bleeker, Eleni A. Spyropoulou, Paul J. Diergaarde, Hanne Volpin, Michiel T. J. Both, Philipp Zerbe, Joerg Bohlmann, Vasiliki Falara, Yuki Matsuba, Eran Pichersky
    Abstract:

    Solanum lycopersicum and Solanum Habrochaites (f. typicum ) accession PI127826 emit a variety of sesquiterpenes. To identify terpene synthases involved in the production of these volatile sesquiterpenes, we used massive parallel pyrosequencing (RNA-seq) to obtain the transcriptome of the stem trichomes from these plants . This approach resulted initially in the discovery of six sesquiterpene synthase cDNAs from S. lycopersicum and five from S. Habrochaites . Searches of other databases and the S. lycopersicum genome resulted in the discovery of two additional sesquiterpene synthases expressed in trichomes. The sesquiterpene synthases from S. lycopersicum and S. Habrochaites have high levels of protein identity. Several of them appeared to encode for non-functional proteins. Functional recombinant proteins produced germacrenes, β-caryophyllene/α-humulene, viridiflorene and valencene from ( E,E )-farnesyl diphosphate. However, the activities of these enzymes do not completely explain the differences in sesquiterpene production between the two tomato plants. RT-qPCR confirmed high levels of expression of most of the S. lycopersicum sesquiterpene synthases in stem trichomes. In addition, one sesquiterpene synthase was induced by jasmonic acid, while another appeared to be slightly repressed by the treatment. Our data provide a foundation to study the evolution of terpene synthases in cultivated and wild tomato.

  • polymethylated myricetin in trichomes of the wild tomato species Solanum Habrochaites and characterization of trichome specific 3 5 and 7 4 myricetin o methyltransferases
    Plant Physiology, 2011
    Co-Authors: Adam Schmidt, Daniel A Jones, Chao Li, Eran Pichersky
    Abstract:

    Flavonoids are a class of metabolites found in many plant species. They have been reported to serve several physiological roles, such as in defense against herbivores and pathogens and in protection against harmful ultraviolet radiation. They also serve as precursors of pigment compounds found in flowers, leaves, and seeds. Highly methylated, nonglycosylated derivatives of the flavonoid myricetin flavonoid, have been previously reported from a variety of plants, but O-methyltransferases responsible for their synthesis have not yet been identified. Here, we show that secreting glandular trichomes (designated types 1 and 4) and storage glandular trichomes (type 6) on the leaf surface of wild tomato (Solanum Habrochaites accession LA1777) plants contain 3,7,3′-trimethyl myricetin, 3,7,3′,5′-tetramethyl myricetin, and 3,7,3′,4′,5′-pentamethyl myricetin, with gland types 1 and 4 containing severalfold more of these compounds than type 6 glands and with the tetramethylated compound predominating in all three gland types. We have also identified transcripts of two genes expressed in the glandular trichomes and showed that they encode enzymes capable of methylating myricetin at the 3′ and 5′ and the 7 and 4′ positions, respectively. Both genes are preferentially expressed in secreting glandular trichome types 1 and 4 and to a lesser degree in storage trichome type 6, and the levels of the proteins they encode are correspondingly higher in types 1 and 4 glands compared with type 6 glands.

  • multiple biochemical and morphological factors underlie the production of methylketones in tomato trichomes
    Plant Physiology, 2009
    Co-Authors: Imri Benisrael, Eran Pichersky, Geng Yu, Michael B Austin, Nazmul H Bhuiyan, M E Auldridge, Thuong T H Nguyen, Ines Schauvinhold, Joseph P Noel, Eyal Fridman
    Abstract:

    Genetic analysis of interspecific populations derived from crosses between the wild tomato species Solanum Habrochaites f. sp. glabratum, which synthesizes and accumulates insecticidal methylketones (MK), mostly 2-undecanone and 2-tridecanone, in glandular trichomes, and cultivated tomato (Solanum lycopersicum), which does not, demonstrated that several genetic loci contribute to MK metabolism in the wild species. A strong correlation was found between the shape of the glandular trichomes and their MK content, and significant associations were seen between allelic states of three genes and the amount of MK produced by the plant. Two genes belong to the fatty acid biosynthetic pathway, and the third is the previously identified Methylketone Synthase1 (MKS1) that mediates conversion to MK of β-ketoacyl intermediates. Comparative transcriptome analysis of the glandular trichomes of F2 progeny grouped into low- and high-MK-containing plants identified several additional genes whose transcripts were either more or less abundant in the high-MK bulk. In particular, a wild species-specific transcript for a gene that we named MKS2, encoding a protein with some similarity to a well-characterized bacterial thioesterase, was approximately 300-fold more highly expressed in F2 plants with high MK content than in those with low MK content. Genetic analysis in the segregating population showed that MKS2's significant contribution to MK accumulation is mediated by an epistatic relationship with MKS1. Furthermore, heterologous expression of MKS2 in Escherichia coli resulted in the production of methylketones in this host.

Hui Liu - One of the best experts on this subject based on the ideXlab platform.

  • molecular and functional characterization of shnac1 an nac transcription factor from Solanum Habrochaites
    Plant Science, 2018
    Co-Authors: Hui Liu, Yuhong Zhou, Taotao Wang, Junhong Zhang, Bo Ouyang
    Abstract:

    NAC transcription factors (TFs) are important regulators of plant adaptation to abiotic stress. In this study, we functionally characterized an NAC TF, ShNAC1, from Solanum Habrochaites. ShNAC1 was up-regulated by drought, cold, and salt stresses, and it displayed lower expression at the late stage of stress treatments than its orthologous gene in S. lycopersicum. Overexpression of ShNAC1 in tomato resulted in reduced cold, drought, and salt tolerance. Additionally, ShNAC1 displayed the highest expression in senescent leaf, and overexpressing ShNAC1 accelerated salt- and dark-induced leaf senescence. ShNAC1 was located in the nucleus without transactivation activity. RNA-seq analysis revealed that 81% (190 out of 234) differentially-expressed genes (DEGs) showed down-regulation in the transgenic line L2 compared with wild-type, suggesting that ShNAC1 may function as a transcriptional repressor. Among these down-regulated DEGs, many were involved in stress responses, such as SlHKT1;1, SlMAPKKK59, SlJA2, SlTIL, SlALDH2B1, etc. Noticeably, one ACS gene and three ACO genes involved in ethylene biosynthesis were up-regulated, while seven ERF genes in the ethylene signal transduction pathway were down-regulated in the transgenic lines, respectively. Our results suggested that ShNAC1 negatively regulates tolerance to abiotic stress in tomato probably by modulating the ethylene biosynthesis and signal transduction pathways.

  • overexpression of calmodulin like shcml44 stress responsive gene from Solanum Habrochaites enhances tolerance to multiple abiotic stresses
    Scientific Reports, 2016
    Co-Authors: Shoaib Munir, Hui Liu, Bo Ouyang, Yali Xing, Saddam Hussain, Yuyang Zhang
    Abstract:

    Calmodulin-like (CML) proteins are important Ca(2+) sensors, which play significant role in mediating plant stress tolerance. In the present study, cold responsive calmodulin-like (ShCML44) gene was isolated from cold tolerant wild tomato (Solanum Habrochaites), and functionally characterized. The ShCML44 was differentially expressed in all plant tissues including root, stem, leaf, flower and fruit, and was strongly up-regulated under cold, drought and salinity stresses along with plant growth hormones. Under cold stress, progressive increase in the expression of ShCML44 was observed particularly in cold-tolerant S. Habrochaites. The ShCML44-overexpressed plants showed greater tolerance to cold, drought, and salinity stresses, and recorded higher germination and better seedling growth. Transgenic tomato plants demonstrated higher antioxidant enzymes activity, gas exchange and water retention capacity with lower malondialdehyde accumulation and membrane damage under cold and drought stresses compared to wild-type. Moreover, transgenic plants exhibited reduced reactive oxygen species and higher relative water contents under cold and drought stress, respectively. Greater stress tolerance of transgenic plants was further reflected by the up-/down-regulation of stress-related genes including SOD, GST, CAT, POD, LOX, PR and ERD. In crux, these results strengthen the molecular understanding of ShCML44 gene to improve the abiotic stress tolerance in tomato.

  • Z: Differential modulation of photosynthesis, signaling, and transcriptional regulation between tolerant and sensitive tomato genotypes under cold stress. PLoS One 2012
    2016
    Co-Authors: Hui Liu, Taotao Wang, Junhong Zhang, Bo Ouyang, Yuyang Zhang
    Abstract:

    The wild species Solanum Habrochaites is more cold tolerant than the cultivated tomato (S. lycopersicum). To explore the mechanisms underlying cold tolerance of S. Habrochaites, seedlings of S. Habrochaites LA1777 introgression lines (ILs), as well as the two parents, were evaluated under low temperature (4uC). The IL LA3969 and its donor parent LA1777 were found to be more cold tolerant than the recurrent parent S. lycopersicum LA4024. The differences in physiology and global gene expression between cold-tolerant (LA1777 and LA3969) and-sensitive (LA4024) genotypes under cold stress were further investigated. Comparative transcriptome analysis identified 1613, 1456, and 1523 cold-responsive genes in LA1777, LA3969, and LA4024, respectively. Gene ontology (GO) term enrichment analysis revealed that more GO biological process terms were significantly enriched among the up-regulated genes in the two tolerant genotypes, whereas more biological processes were significantly repressed by cold stress in the sensitive one. A total of 92 genes with significant differential expression between tolerant and sensitive genotypes under cold stress were identified. Among these, many stress-related GO terms were significantly enriched, such as ‘response to stimulus ’ and ‘response to stress’. Moreover, GO terms ‘response to hormone stimulus’, ‘response to reactive oxygen species (ROS)’, and ‘calcium-mediated signaling ’ were also overrepresented. Several transcripts involved in hormone or ROS homeostasis were also differentially expressed. ROS, hormones, and calcium as signaling molecules may play important roles in regulating gene expression in response to col

  • overexpression of shdhn a dehydrin gene from Solanum Habrochaites enhances tolerance to multiple abiotic stresses in tomato
    Plant Science, 2015
    Co-Authors: Hui Liu, Taotao Wang, Junhong Zhang, Bo Ouyang, Xin Wang
    Abstract:

    Dehydrins (DHNs) play important roles in plant adaptation to abiotic stress. In this study, a cold-induced SK3-type DHN gene (ShDHN) isolated from wild tomato species Solanum Habrochaites was characterized for its function in abiotic stress tolerance. ShDHN was constitutively expressed in root, leaf, stem, flower and fruit. ShDHN was continuously up-regulated during cold stress and showed higher expression level in the cold-tolerant S. Habrochaites than in the susceptible S. lycopersicum. Moreover, ShDHN expression was also regulated by drought, salt, osmotic stress, and exogenous signaling molecules. Overexpression of ShDHN in cultivated tomato increased tolerance to cold and drought stresses and improved seedling growth under salt and osmotic stresses. Compared with the wild-type, the transgenic plants accumulated more proline, maintained higher enzymatic activities of superoxide dismutase and catalase, and suffered less membrane damage under cold and drought stresses. Moreover, the transgenic plants accumulated lower levels of H2O2 and O2(-) under cold stress, and had higher relative water contents and lower water loss rates under dehydration conditions. Furthermore, overexpression of ShDHN in tomato led to the up- or down-regulated expression of several genes involved in ROS scavenging and JA signaling pathway, including SOD1, GST, POD, LOX, PR1 and PR2. Taken together, these results indicate that ShDHN has pleiotropic effects on improving plant adaptation to abiotic stresses and that it possesses potential usefulness in genetic improvement of stress tolerance in tomato.