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Richard S. Hussey - One of the best experts on this subject based on the ideXlab platform.
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Secrets in secretions: genes that control nematode parasitism of plants
2016Co-Authors: Braz Plant J. Physiol, Eric L. Davis, Richard S. Hussey, Thomas J. BaumAbstract:The most evolutionary advanced adaptations for plant parasitism by nematodes are the products of parasitism genes expressed in their Esophageal Gland cells and secreted through their stylet into host tissue to control the complex process of parasitism. Molecular analyses of nematode parasitism genes are revealing the complexity of the tools that enable the nematode to attack plants, and the results paint a more elaborate picture of host cellular events under specific control by the parasite than previously hypothesized. Interestingly, the majority of the parasitism genes discovered encodes proteins unique to plant-parasitic nematodes. Identifying the nematode parasitome, i.e., the complete profile of parasitism gene products secreted through the nematode stylet during the parasitic cycle, is the key to understanding the molecular basis of nematode parasitism of plants. Such knowledge will identify vulnerable points in the parasitic process that can be interfered with to achieve nematode control to limit nematode-induced yield losses in crops. Key words: Esophageal Gland cells, nematode parasitism, parasitome, parasitism genes, secretion. Secredos em secreções: genes tque controlam o parasitismo de nematóides de plantas: As mais avançadas adapta-ções evolucionárias para o parasitismo de plantas por nematóides são os produtos dos genes de parasitismo expressos nas células da sua glândula esofagial e secretados através do estilete no tecido do hospedeiro, com a finalidade de controlar o complexo processo de parasitismo. Análises moleculares de genes de parasitismo de nematóides têm revelado a com-plexidade das ferramentas que os permitem atacar as plantas e também obter uma visão mais elaborada do que antes s
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eighteen new candidate effectors of the phytonematode heterodera glycines produced specifically in the secretory Esophageal Gland cells during parasitism
Phytopathology, 2015Co-Authors: Jason B Noon, Eric L. Davis, Tarek Hewezi, Melissa G Mitchum, Thomas R Maier, Carl R Simmons, Junzhi Wei, Victor Llaca, Stephane Deschamps, Richard S. HusseyAbstract:Heterodera glycines, the soybean cyst nematode, is the number one pathogen of soybean (Glycine max). This nematode infects soybean roots and forms an elaborate feeding site in the vascular cylinder. H. glycines produces an arsenal of effector proteins in the secretory Esophageal Gland cells. More than 60 H. glycines candidate effectors were identified in previous Gland-cell-mining projects. However, it is likely that additional candidate effectors remained unidentified. With the goal of identifying remaining H. glycines candidate effectors, we constructed and sequenced a large Gland cell cDNA library resulting in 11,814 expressed sequence tags. After bioinformatic filtering for candidate effectors using a number of criteria, in situ hybridizations were performed in H. glycines whole-mount specimens to identify candidate effectors whose mRNA exclusively accumulated in the Esophageal Gland cells, which is a hallmark of many nematode effectors. This approach resulted in the identification of 18 new H. glycines Esophageal Gland-cell-specific candidate effectors. Of these candidate effectors, 11 sequences were pioneers without similarities to known proteins while 7 sequences had similarities to functionally annotated proteins in databases. These putative homologies provided the bases for the development of hypotheses about potential functions in the parasitism process.
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the 8d05 parasitism gene of meloidogyne incognita is required for successful infection of host roots
Phytopathology, 2013Co-Authors: Noureddine Hamamouch, Thomas J. Baum, Richard S. Hussey, Guozhong Huang, Chunying Li, Eric L. DavisAbstract:ABSTRACT Parasitism genes encode effector proteins that are secreted through the stylet of root-knot nematodes to dramatically modify selected plant cells into giant-cells for feeding. The Mi8D05 parasitism gene previously identified was confirmed to encode a novel protein of 382 amino acids that had only one database homolog identified on contig 2374 within the Meloidogyne hapla genome. Mi8D05 expression peaked in M. incognita parasitic second-stage juveniles within host roots and its encoded protein was limited to the subventral Esophageal Gland cells that produce proteins secreted from the stylet. Constitutive expression of Mi8D05 in transformed Arabidopsis thaliana plants induced accelerated shoot growth and early flowering but had no visible effects on root growth. Independent lines of transgenic Arabidopsis that expressed a double-stranded RNA complementary to Mi8D05 in host-derived RNA interference (RNAi) tests had up to 90% reduction in infection by M. incognita compared with wild-type control pla...
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engineering broad root knot resistance in transgenic plants by rnai silencing of a conserved and essential root knot nematode parasitism gene
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Guozhong Huang, Eric L. Davis, Thomas J. Baum, Rex Allen, Richard S. HusseyAbstract:Secreted parasitism proteins encoded by parasitism genes expressed in Esophageal Gland cells mediate infection and parasitism of plants by root-knot nematodes (RKN). Parasitism gene 16D10 encodes a conserved RKN secretory peptide that stimulates root growth and functions as a ligand for a putative plant transcription factor. We used in vitro and in vivo RNA interference approaches to silence this parasitism gene in RKN and validate that the parasitism gene has an essential function in RKN parasitism of plants. Ingestion of 16D10 dsRNA in vitro silenced the target parasitism gene in RKN and resulted in reduced nematode infectivity. In vivo expression of 16D10 dsRNA in Arabidopsis resulted in resistance effective against the four major RKN species. Because no known natural resistance gene has this wide effective range of RKN resistance, bioengineering crops expressing dsRNA that silence target RKN parasitism genes to disrupt the parasitic process represents a viable and flexible means of developing novel durable RKN-resistant crops and could provide crops with unprecedented broad resistance to RKN.
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a root knot nematode secretory peptide functions as a ligand for a plant transcription factor
Molecular Plant-microbe Interactions, 2006Co-Authors: Guozhong Huang, Eric L. Davis, Thomas J. Baum, Ruihua Dong, Rex Allen, Richard S. HusseyAbstract:Parasitism genes expressed in the Esophageal Gland cells of root-knot nematodes encode proteins that are secreted into host root cells to transform the recipient cells into enlarged multinucleate feeding cells called giant-cells. Expression of a root-knot nematode parasitism gene which encodes a novel 13-amino-acid secretory peptide in plant tissues stimulated root growth. Two SCARECROW-like transcription factors of the GRAS protein family were identified as the putative targets for this bioactive nematode peptide in yeast two-hybrid analyses and confirmed by in vitro and in vivo coimmunoprecipitations. This discovery is the first demonstration of a direct interaction of a nematode-secreted parasitism peptide with a plant-regulatory protein, which may represent an early signaling event in the root-knot nematode-host interaction.
Eric L. Davis - One of the best experts on this subject based on the ideXlab platform.
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Secrets in secretions: genes that control nematode parasitism of plants
2016Co-Authors: Braz Plant J. Physiol, Eric L. Davis, Richard S. Hussey, Thomas J. BaumAbstract:The most evolutionary advanced adaptations for plant parasitism by nematodes are the products of parasitism genes expressed in their Esophageal Gland cells and secreted through their stylet into host tissue to control the complex process of parasitism. Molecular analyses of nematode parasitism genes are revealing the complexity of the tools that enable the nematode to attack plants, and the results paint a more elaborate picture of host cellular events under specific control by the parasite than previously hypothesized. Interestingly, the majority of the parasitism genes discovered encodes proteins unique to plant-parasitic nematodes. Identifying the nematode parasitome, i.e., the complete profile of parasitism gene products secreted through the nematode stylet during the parasitic cycle, is the key to understanding the molecular basis of nematode parasitism of plants. Such knowledge will identify vulnerable points in the parasitic process that can be interfered with to achieve nematode control to limit nematode-induced yield losses in crops. Key words: Esophageal Gland cells, nematode parasitism, parasitome, parasitism genes, secretion. Secredos em secreções: genes tque controlam o parasitismo de nematóides de plantas: As mais avançadas adapta-ções evolucionárias para o parasitismo de plantas por nematóides são os produtos dos genes de parasitismo expressos nas células da sua glândula esofagial e secretados através do estilete no tecido do hospedeiro, com a finalidade de controlar o complexo processo de parasitismo. Análises moleculares de genes de parasitismo de nematóides têm revelado a com-plexidade das ferramentas que os permitem atacar as plantas e também obter uma visão mais elaborada do que antes s
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eighteen new candidate effectors of the phytonematode heterodera glycines produced specifically in the secretory Esophageal Gland cells during parasitism
Phytopathology, 2015Co-Authors: Jason B Noon, Eric L. Davis, Tarek Hewezi, Melissa G Mitchum, Thomas R Maier, Carl R Simmons, Junzhi Wei, Victor Llaca, Stephane Deschamps, Richard S. HusseyAbstract:Heterodera glycines, the soybean cyst nematode, is the number one pathogen of soybean (Glycine max). This nematode infects soybean roots and forms an elaborate feeding site in the vascular cylinder. H. glycines produces an arsenal of effector proteins in the secretory Esophageal Gland cells. More than 60 H. glycines candidate effectors were identified in previous Gland-cell-mining projects. However, it is likely that additional candidate effectors remained unidentified. With the goal of identifying remaining H. glycines candidate effectors, we constructed and sequenced a large Gland cell cDNA library resulting in 11,814 expressed sequence tags. After bioinformatic filtering for candidate effectors using a number of criteria, in situ hybridizations were performed in H. glycines whole-mount specimens to identify candidate effectors whose mRNA exclusively accumulated in the Esophageal Gland cells, which is a hallmark of many nematode effectors. This approach resulted in the identification of 18 new H. glycines Esophageal Gland-cell-specific candidate effectors. Of these candidate effectors, 11 sequences were pioneers without similarities to known proteins while 7 sequences had similarities to functionally annotated proteins in databases. These putative homologies provided the bases for the development of hypotheses about potential functions in the parasitism process.
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the 8d05 parasitism gene of meloidogyne incognita is required for successful infection of host roots
Phytopathology, 2013Co-Authors: Noureddine Hamamouch, Thomas J. Baum, Richard S. Hussey, Guozhong Huang, Chunying Li, Eric L. DavisAbstract:ABSTRACT Parasitism genes encode effector proteins that are secreted through the stylet of root-knot nematodes to dramatically modify selected plant cells into giant-cells for feeding. The Mi8D05 parasitism gene previously identified was confirmed to encode a novel protein of 382 amino acids that had only one database homolog identified on contig 2374 within the Meloidogyne hapla genome. Mi8D05 expression peaked in M. incognita parasitic second-stage juveniles within host roots and its encoded protein was limited to the subventral Esophageal Gland cells that produce proteins secreted from the stylet. Constitutive expression of Mi8D05 in transformed Arabidopsis thaliana plants induced accelerated shoot growth and early flowering but had no visible effects on root growth. Independent lines of transgenic Arabidopsis that expressed a double-stranded RNA complementary to Mi8D05 in host-derived RNA interference (RNAi) tests had up to 90% reduction in infection by M. incognita compared with wild-type control pla...
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The novel cyst nematode effector protein 19C07 interacts with the Arabidopsis auxin influx transporter LAX3 to control feeding site development.
Plant Physiology, 2011Co-Authors: Chris Lee, Eric L. Davis, Thomas J. Baum, Demosthenis Chronis, Charlotte Kenning, Benjamin Peret, Tarek Hewezi, Richard Hussey, Malcolm Bennett, Melissa G MitchumAbstract:Plant-parasitic cyst nematodes penetrate plant roots and transform cells near the vasculature into specialized feeding sites called syncytia. Syncytia form by incorporating neighboring cells into a single fused cell by cell wall dissolution. This process is initiated via injection of Esophageal Gland cell effector proteins from the nematode stylet into the host cell. Once inside the cell, these proteins may interact with host proteins that regulate the phytohormone auxin, as cellular concentrations of auxin increase in developing syncytia. Soybean cyst nematode (Heterodera glycines) Hg19C07 is a novel effector protein expressed specifically in the dorsal Gland cell during nematode parasitism. Here, we describe its ortholog in the beet cyst nematode (Heterodera schachtii), Hs19C07. We demonstrate that Hs19C07 interacts with the Arabidopsis (Arabidopsis thaliana) auxin influx transporter LAX3. LAX3 is expressed in cells overlying lateral root primordia, providing auxin signaling that triggers the expression of cell wall-modifying enzymes, allowing lateral roots to emerge. We found that LAX3 and polygalacturonase, a LAX3-induced cell wall-modifying enzyme, are expressed in the developing syncytium and in cells to be incorporated into the syncytium. We observed no decrease in H. schachtii infectivity in aux1 and lax3 single mutants. However, a decrease was observed in both the aux1lax3 double mutant and the aux1lax1lax2lax3 quadruple mutant. In addition, ectopic expression of 19C07 was found to speed up lateral root emergence. We propose that Hs19C07 most likely increases LAX3-mediated auxin influx and may provide a mechanism for cyst nematodes to modulate auxin flow into root cells, stimulating cell wall hydrolysis for syncytium development.
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engineering broad root knot resistance in transgenic plants by rnai silencing of a conserved and essential root knot nematode parasitism gene
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Guozhong Huang, Eric L. Davis, Thomas J. Baum, Rex Allen, Richard S. HusseyAbstract:Secreted parasitism proteins encoded by parasitism genes expressed in Esophageal Gland cells mediate infection and parasitism of plants by root-knot nematodes (RKN). Parasitism gene 16D10 encodes a conserved RKN secretory peptide that stimulates root growth and functions as a ligand for a putative plant transcription factor. We used in vitro and in vivo RNA interference approaches to silence this parasitism gene in RKN and validate that the parasitism gene has an essential function in RKN parasitism of plants. Ingestion of 16D10 dsRNA in vitro silenced the target parasitism gene in RKN and resulted in reduced nematode infectivity. In vivo expression of 16D10 dsRNA in Arabidopsis resulted in resistance effective against the four major RKN species. Because no known natural resistance gene has this wide effective range of RKN resistance, bioengineering crops expressing dsRNA that silence target RKN parasitism genes to disrupt the parasitic process represents a viable and flexible means of developing novel durable RKN-resistant crops and could provide crops with unprecedented broad resistance to RKN.
Thomas J. Baum - One of the best experts on this subject based on the ideXlab platform.
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Secrets in secretions: genes that control nematode parasitism of plants
2016Co-Authors: Braz Plant J. Physiol, Eric L. Davis, Richard S. Hussey, Thomas J. BaumAbstract:The most evolutionary advanced adaptations for plant parasitism by nematodes are the products of parasitism genes expressed in their Esophageal Gland cells and secreted through their stylet into host tissue to control the complex process of parasitism. Molecular analyses of nematode parasitism genes are revealing the complexity of the tools that enable the nematode to attack plants, and the results paint a more elaborate picture of host cellular events under specific control by the parasite than previously hypothesized. Interestingly, the majority of the parasitism genes discovered encodes proteins unique to plant-parasitic nematodes. Identifying the nematode parasitome, i.e., the complete profile of parasitism gene products secreted through the nematode stylet during the parasitic cycle, is the key to understanding the molecular basis of nematode parasitism of plants. Such knowledge will identify vulnerable points in the parasitic process that can be interfered with to achieve nematode control to limit nematode-induced yield losses in crops. Key words: Esophageal Gland cells, nematode parasitism, parasitome, parasitism genes, secretion. Secredos em secreções: genes tque controlam o parasitismo de nematóides de plantas: As mais avançadas adapta-ções evolucionárias para o parasitismo de plantas por nematóides são os produtos dos genes de parasitismo expressos nas células da sua glândula esofagial e secretados através do estilete no tecido do hospedeiro, com a finalidade de controlar o complexo processo de parasitismo. Análises moleculares de genes de parasitismo de nematóides têm revelado a com-plexidade das ferramentas que os permitem atacar as plantas e também obter uma visão mais elaborada do que antes s
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a ubiquitin carboxyl extension protein secreted from a plant parasitic nematode globodera rostochiensis is cleaved in planta to promote plant parasitism
Plant Journal, 2013Co-Authors: Demosthenis Chronis, Thomas J. Baum, Xiaohong Wang, Tarek Hewezi, Shiyan Chen, Sara C D Carpenter, Rosemary LoriaAbstract:Nematode effector proteins originating from Esophageal Gland cells play central roles in suppressing plant defenses and in formation of the plant feeding cells that are required for growth and development of cyst nematodes. A gene (GrUBCEP12) encoding a unique ubiquitin carboxyl extension protein (UBCEP) that consists of a signal peptide for secretion, a mono-ubiquitin domain, and a 12 amino acid carboxyl extension protein (CEP12) domain was cloned from the potato cyst nematode Globodera rostochiensis. This GrUBCEP12 gene was expressed exclusively within the nematode's dorsal Esophageal Gland cell, and was up-regulated in the parasitic second-stage juvenile, correlating with the time when feeding cell formation is initiated. We showed that specific GrUBCEP12 knockdown via RNA interference reduced nematode parasitic success, and that over-expression of the secreted Gr(Δ) (SP) UBCEP12 protein in potato resulted in increased nematode susceptibility, providing direct evidence that this secreted effector is involved in plant parasitism. Using transient expression assays in Nicotiana benthamiana, we found that Gr(Δ) (SP) UBCEP12 is processed into free ubiquitin and a CEP12 peptide (GrCEP12) in planta, and that GrCEP12 suppresses resistance gene-mediated cell death. A target search showed that expression of RPN2a, a gene encoding a subunit of the 26S proteasome, was dramatically suppressed in Gr(Δ) (SP) UBCEP12 but not GrCEP12 over-expression plants when compared with control plants. Together, these results suggest that, when delivered into host plant cells, Gr(Δ) (SP) UBCEP12 becomes two functional units, one acting to suppress plant immunity and the other potentially affecting the host 26S proteasome, to promote feeding cell formation.
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the 8d05 parasitism gene of meloidogyne incognita is required for successful infection of host roots
Phytopathology, 2013Co-Authors: Noureddine Hamamouch, Thomas J. Baum, Richard S. Hussey, Guozhong Huang, Chunying Li, Eric L. DavisAbstract:ABSTRACT Parasitism genes encode effector proteins that are secreted through the stylet of root-knot nematodes to dramatically modify selected plant cells into giant-cells for feeding. The Mi8D05 parasitism gene previously identified was confirmed to encode a novel protein of 382 amino acids that had only one database homolog identified on contig 2374 within the Meloidogyne hapla genome. Mi8D05 expression peaked in M. incognita parasitic second-stage juveniles within host roots and its encoded protein was limited to the subventral Esophageal Gland cells that produce proteins secreted from the stylet. Constitutive expression of Mi8D05 in transformed Arabidopsis thaliana plants induced accelerated shoot growth and early flowering but had no visible effects on root growth. Independent lines of transgenic Arabidopsis that expressed a double-stranded RNA complementary to Mi8D05 in host-derived RNA interference (RNAi) tests had up to 90% reduction in infection by M. incognita compared with wild-type control pla...
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manipulation of plant cells by cyst and root knot nematode effectors
Molecular Plant-microbe Interactions, 2013Co-Authors: Tarek Hewezi, Thomas J. BaumAbstract:A key feature of sedentary plant-parasitic nematodes is the release of effector proteins from their Esophageal Gland cells through their stylets into host roots. These proteinaceous stylet secretions have been shown to be crucial for successful parasitism by mediating the transition of normal root cells into specialized feeding sites and by negating plant defenses. Recent technical advances of purifying mRNA from Esophageal Gland cells of plant-parasitic nematodes coupled with emerging sequencing technologies is steadily expanding our knowledge of nematode effector repertoires. Host targets and biological activities of a number of nematode effectors are continuously being reported and, by now, a first picture of the complexity of sedentary nematode parasitism at the molecular level is starting to take shape. In this review, we highlight effector mechanisms that recently have been uncovered by studying the host–pathogen interaction. These mechanisms range from mediating susceptibility of host plants to the...
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The novel cyst nematode effector protein 19C07 interacts with the Arabidopsis auxin influx transporter LAX3 to control feeding site development.
Plant Physiology, 2011Co-Authors: Chris Lee, Eric L. Davis, Thomas J. Baum, Demosthenis Chronis, Charlotte Kenning, Benjamin Peret, Tarek Hewezi, Richard Hussey, Malcolm Bennett, Melissa G MitchumAbstract:Plant-parasitic cyst nematodes penetrate plant roots and transform cells near the vasculature into specialized feeding sites called syncytia. Syncytia form by incorporating neighboring cells into a single fused cell by cell wall dissolution. This process is initiated via injection of Esophageal Gland cell effector proteins from the nematode stylet into the host cell. Once inside the cell, these proteins may interact with host proteins that regulate the phytohormone auxin, as cellular concentrations of auxin increase in developing syncytia. Soybean cyst nematode (Heterodera glycines) Hg19C07 is a novel effector protein expressed specifically in the dorsal Gland cell during nematode parasitism. Here, we describe its ortholog in the beet cyst nematode (Heterodera schachtii), Hs19C07. We demonstrate that Hs19C07 interacts with the Arabidopsis (Arabidopsis thaliana) auxin influx transporter LAX3. LAX3 is expressed in cells overlying lateral root primordia, providing auxin signaling that triggers the expression of cell wall-modifying enzymes, allowing lateral roots to emerge. We found that LAX3 and polygalacturonase, a LAX3-induced cell wall-modifying enzyme, are expressed in the developing syncytium and in cells to be incorporated into the syncytium. We observed no decrease in H. schachtii infectivity in aux1 and lax3 single mutants. However, a decrease was observed in both the aux1lax3 double mutant and the aux1lax1lax2lax3 quadruple mutant. In addition, ectopic expression of 19C07 was found to speed up lateral root emergence. We propose that Hs19C07 most likely increases LAX3-mediated auxin influx and may provide a mechanism for cyst nematodes to modulate auxin flow into root cells, stimulating cell wall hydrolysis for syncytium development.
Kris N Lambert - One of the best experts on this subject based on the ideXlab platform.
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Immunolocalization of HgSNARE-like protein-1 (HgSLP-1).
2016Co-Authors: Sadia Bekal, Leslie L. Domier, Biruk Gonfa, Naoufal Lakhssassi, Khalid Meksem, Kris N LambertAbstract:Panels A—D are 40 x light field images matched with corresponding epiflorescent images of sections of SCN in soybean roots stained using HgSLP-1 antibodies. Arrows point to the basal cell of a subventral Esophageal Gland in A, the median bulb and Esophageal lumen in B and the stylet in C. Panel D shows negative control sections lacking HgSLP-1 antibody staining in the nematode. Arrows in D point to the basal cell of an Esophageal Gland and the stylet. Panel D is a composite of two sequential sections from the same nematode. For all light field images, 20 micron scale bars are shown.
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a snare like protein and biotin are implicated in soybean cyst nematode virulence
PLOS ONE, 2015Co-Authors: Sadia Bekal, Leslie L. Domier, Biruk Gonfa, Naoufal Lakhssassi, Khalid Meksem, Kris N LambertAbstract:Phytoparasitic nematodes that are able to infect and reproduce on plants that are considered resistant are referred to as virulent. The mechanism(s) that virulent nematodes employ to evade or suppress host plant defenses are not well understood. Here we report the use of a genetic strategy (allelic imbalance analysis) to associate single nucleotide polymorphisms (SNPs) with nematode virulence genes in Heterodera glycines, the soybean cyst nematode (SCN). To accomplish this analysis, a custom SCN SNP array was developed and used to genotype SCN F3-derived populations grown on resistant and susceptible soybean plants. Three SNPs reproducibly showed allele imbalances between nematodes grown on resistant and susceptible plants. Two candidate SCN virulence genes that were tightly linked to the SNPs were identified. One SCN gene encoded biotin synthase (HgBioB), and the other encoded a bacterial-like protein containing a putative SNARE domain (HgSLP-1). The two genes mapped to two different linkage groups. HgBioB contained sequence polymorphisms between avirulent and virulent nematodes. However, the gene encoding HgSLP-1 had reduced copy number in virulent nematode populations and appears to produce multiple forms of the protein via intron retention and alternative splicing. We show that HgSLP-1 is an Esophageal-Gland protein that is secreted by the nematode during plant parasitism. Furthermore, in bacterial co-expression experiments, HgSLP-1 co-purified with the SCN resistance protein Rhg1 α-SNAP, suggesting that these two proteins physically interact. Collectively our data suggest that multiple SCN genes are involved in SCN virulence, and that HgSLP-1 may function as an avirulence protein and when absent it helps SCN evade host defenses.
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meloidogyne javanica chorismate mutase transcript expression profile using real time quantitative rt pcr
Journal of Nematology, 2003Co-Authors: Janet E Painter, Kris N LambertAbstract:A developmental expression profile of the Meloidodgyne javanica Esophageal Gland gene chorismate mutase-1 (Mj-cm-1) could suggest when in the lifecycle of the nematode the Mj-cm-1 product is functional. This study used real-time quantitative RT-PCR to examine the variation in Mj-cm-1 transcript levels over six timepoints in the nematode lifecycle: egg, infective second-stage juveniles (Inf-J2), 2-day post-inoculation (pi), 7-day pi, 14-day pi, and adult. The Mj-cm-1 mRNA levels peaked at 2-day pi, about 100-fold above levels expressed at the egg and Inf-J2 stages. Some expression of Mj-cm-1 remained during the 7-day pi, 14-day pi, and adult stages. High transcript levels of the beta-actin control gene M. javanica Beta-actin-1 (Mj-ba-1) demonstrated the presence of cDNA at all timepoints. The peak in Mj-cm-1 transcript expression at 2-day pi as well as the previously shown Esophageal Gland localization of Mj-cm-1 mRNA suggest that the product of this gene may be involved early in the establishment of parasitism.
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meloidogyne javanica chorismate mutase 1 alters plant cell development
Molecular Plant-microbe Interactions, 2003Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their Esophageal Glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such Esophageal Gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA bio...
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Meloidogyne javanica chorismate mutase 1 alters plant cell development.
Molecular plant-microbe interactions : MPMI, 2003Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their Esophageal Glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such Esophageal Gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA biosynthesis. We propose MjCM-1 lowers IAA by causing a competition for chorismate, resulting in an alteration of chorismate-derived metabolites and, ultimately, in plant cell development. Therefore, we hypothesize that MjCM-1 is involved in allowing nematodes to establish a parasitic relationship with the host plant.
Elizabeth A Doyle - One of the best experts on this subject based on the ideXlab platform.
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meloidogyne javanica chorismate mutase 1 alters plant cell development
Molecular Plant-microbe Interactions, 2003Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their Esophageal Glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such Esophageal Gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA bio...
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Meloidogyne javanica chorismate mutase 1 alters plant cell development.
Molecular plant-microbe interactions : MPMI, 2003Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their Esophageal Glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such Esophageal Gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA biosynthesis. We propose MjCM-1 lowers IAA by causing a competition for chorismate, resulting in an alteration of chorismate-derived metabolites and, ultimately, in plant cell development. Therefore, we hypothesize that MjCM-1 is involved in allowing nematodes to establish a parasitic relationship with the host plant.
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cloning and characterization of an Esophageal Gland specific pectate lyase from the root knot nematode meloidogyne javanica
Molecular Plant-microbe Interactions, 2002Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes (Meloidogyne javanica) are obligate sedentary endoparasites that must penetrate the host root to initiate their life cycle. Many enzymes are secreted by the nematode to facilitate host penetration; required enzymes may include pectate lyases and cellulases. Using differential screening, a class III pectate lyase, Mj-pel-1 (M. javanica pectate lyase 1), was cloned from a library enriched for Esophageal Gland genes. DNA gel blotting confirmed that the Mj-pel-1 gene was of nematode origin and a member of a small multigene family. In situ hybridization localized the expression of Mj-pel-1 to the basal cells of the Esophageal Glands, while immunolocalization detected the protein in the Esophageal Glands as well as on the exterior of the nematode, confirming that the protein is secreted. When MJ-PEL-1 was expressed in Pichia pastoris, the resulting protein was active. The pH optimum of MJ-PEL-1 was 10.0, and the enzyme was five times more active on pectate than on pectin. Like other class II...
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cloning and characterization of an Esophageal Gland specific pectate lyase from the root knot nematode meloidogyne javanica
Molecular Plant-microbe Interactions, 2002Co-Authors: Elizabeth A Doyle, Kris N LambertAbstract:Root-knot nematodes (Meloidogynejavanica) are obligate sedentary endoparasites that must penetrate the host root to initiate their life cycle. Many enzymes are secreted by the nematode to facilitate host penetration; required enzymes may include pectate lyases and cellulases. Using differential screening, a class III pectate lyase, Mj-pel-1 (M. javanica pectate lyase 1), was cloned from a library enriched for Esophageal Gland genes. DNA gel blotting confirmed that the Mj-pel-1 gene was of nematode origin and a member of a small multigene family. In situ hybridization localized the expression of Mj-pel-1 to the basal cells of the Esophageal Glands, while immunolocalization detected the protein in the Esophageal Glands as well as on the exterior of the nematode, confirming that the protein is secreted. When MJ-PEL-1 was expressed in Pichia pastoris, the resulting protein was active. The pH optimum of MJ-PEL-1 was 10.0, and the enzyme was five times more active on pectate than on pectin. Like other class III pectate lyases, MJ-PEL-1 also displayed an absolute requirement for Ca2+. The root-knot nematode migrates through the middle lamella of the plant root; therefore, MJ-PEL-1 may be an important enzyme early in the infection process.