ABSTRACT Tung oil, the major product of tung tree (Vernicia fordii) seeds, is one of the highest ... more ABSTRACT Tung oil, the major product of tung tree (Vernicia fordii) seeds, is one of the highest quality oils for industrial applications and has been considered for the production of biodiesel. Considering the poor agronomical traits of this crop, efforts have been made to breed tung trees for a higher fruit yield and oil property modification for biodiesel use or to engineer plants to produce a higher tung oil yield. However, these efforts have been hampered by a lack of molecular information, as there is no available genome and identified and characterized transcripts of this tree are scarce. Furthermore, there are still many knowledge gaps regarding tung oil biosynthesis. To provide a comprehensive and accurate foundation for molecular studies of tung tree, we present here a reference transcriptome dataset of mature tung seeds. A set of 43,081,927 reads were assembled into 47,585 unigenes. A homology search using blastx against the GenBank nonredundant protein database and the Swiss-Prot database resulted in the annotation of 96 and 81 % of these unigenes, respectively. We also systematically arranged a series of unigenes potentially associated with oil biosynthesis and degradation and examined the expression profile of a subset of those genes in samples from five different stages of seed development, providing a valuable source of genes and transcriptional information related to these pathways. This study represents the first large-scale transcriptome annotation of tung tree and will be useful in tung breeding for oil properties and other agronomical traits.
Jasmonates are plant signaling molecules that play key roles in protection against certain pathog... more Jasmonates are plant signaling molecules that play key roles in protection against certain pathogens and against insects by switching on the expression of genes encoding defense proteins including enzymes involved in the biosynthesis of toxic secondary metabolites. In Catharanthus roseus, the ethylene response factor (ERF) transcription factor ORCA3 controls the jasmonate-responsive activation of terpenoid indole alkaloid biosynthetic genes. ORCA3 gene expression is itself induced by jasmonate. Its promoter contains an autonomous jasmonate-responsive element (JRE). Here we describe the jasmonate-responsive activity of the JRE from the ORCA3 promoter in Arabidopsis thaliana. We found that it interacts in vitro and in vivo with the basic helix-loop-helix transcription factor AtMYC2. Analysis of JRE-mediated reporter gene expression in an atmyc2-1 mutant background showed that the activity was strictly dependent on AtMYC2.
Ribosome-inactivating proteins (RIPs) are enzymes that inhibit protein synthesis after depurinati... more Ribosome-inactivating proteins (RIPs) are enzymes that inhibit protein synthesis after depurination of a specific adenine in rRNA. The RIP family members are classified as type I RIPs that contain an RNA-N-glycosidase domain and type II RIPs that contain a lectin domain (B chain) in addition to the glycosidase domain (A chain). In this work, we identified 30 new plant RIPs and characterized 18 Ricinus communis RIPs. Phylogenetic and functional divergence analyses indicated that the emergence of type I and II RIPs probably occurred before the monocot/eudicot split. We also report the expression profiles of 18 castor bean genes, including those for ricin and agglutinin, in five seed stages as assessed by quantitative PCR. Ricin and agglutinin were the most expressed RIPs in developing seeds although eight other RIPs were also expressed. All of the RIP genes were most highly expressed in the stages in which the endosperm was fully expanded. Although the reason for the large expansion of RIP genes in castor beans remains to be established, the differential expression patterns of the type I and type II members reinforce the existence of biological functions other than defense against predators and herbivory.
ABSTRACT Tung oil, the major product of tung tree (Vernicia fordii) seeds, is one of the highest ... more ABSTRACT Tung oil, the major product of tung tree (Vernicia fordii) seeds, is one of the highest quality oils for industrial applications and has been considered for the production of biodiesel. Considering the poor agronomical traits of this crop, efforts have been made to breed tung trees for a higher fruit yield and oil property modification for biodiesel use or to engineer plants to produce a higher tung oil yield. However, these efforts have been hampered by a lack of molecular information, as there is no available genome and identified and characterized transcripts of this tree are scarce. Furthermore, there are still many knowledge gaps regarding tung oil biosynthesis. To provide a comprehensive and accurate foundation for molecular studies of tung tree, we present here a reference transcriptome dataset of mature tung seeds. A set of 43,081,927 reads were assembled into 47,585 unigenes. A homology search using blastx against the GenBank nonredundant protein database and the Swiss-Prot database resulted in the annotation of 96 and 81 % of these unigenes, respectively. We also systematically arranged a series of unigenes potentially associated with oil biosynthesis and degradation and examined the expression profile of a subset of those genes in samples from five different stages of seed development, providing a valuable source of genes and transcriptional information related to these pathways. This study represents the first large-scale transcriptome annotation of tung tree and will be useful in tung breeding for oil properties and other agronomical traits.
Jasmonates are plant signaling molecules that play key roles in protection against certain pathog... more Jasmonates are plant signaling molecules that play key roles in protection against certain pathogens and against insects by switching on the expression of genes encoding defense proteins including enzymes involved in the biosynthesis of toxic secondary metabolites. In Catharanthus roseus, the ethylene response factor (ERF) transcription factor ORCA3 controls the jasmonate-responsive activation of terpenoid indole alkaloid biosynthetic genes. ORCA3 gene expression is itself induced by jasmonate. Its promoter contains an autonomous jasmonate-responsive element (JRE). Here we describe the jasmonate-responsive activity of the JRE from the ORCA3 promoter in Arabidopsis thaliana. We found that it interacts in vitro and in vivo with the basic helix-loop-helix transcription factor AtMYC2. Analysis of JRE-mediated reporter gene expression in an atmyc2-1 mutant background showed that the activity was strictly dependent on AtMYC2.
Ribosome-inactivating proteins (RIPs) are enzymes that inhibit protein synthesis after depurinati... more Ribosome-inactivating proteins (RIPs) are enzymes that inhibit protein synthesis after depurination of a specific adenine in rRNA. The RIP family members are classified as type I RIPs that contain an RNA-N-glycosidase domain and type II RIPs that contain a lectin domain (B chain) in addition to the glycosidase domain (A chain). In this work, we identified 30 new plant RIPs and characterized 18 Ricinus communis RIPs. Phylogenetic and functional divergence analyses indicated that the emergence of type I and II RIPs probably occurred before the monocot/eudicot split. We also report the expression profiles of 18 castor bean genes, including those for ricin and agglutinin, in five seed stages as assessed by quantitative PCR. Ricin and agglutinin were the most expressed RIPs in developing seeds although eight other RIPs were also expressed. All of the RIP genes were most highly expressed in the stages in which the endosperm was fully expanded. Although the reason for the large expansion of RIP genes in castor beans remains to be established, the differential expression patterns of the type I and type II members reinforce the existence of biological functions other than defense against predators and herbivory.
Uploads
Papers by Ana Korbes