WorldWideScience

Sample records for nematode resistance gene

  1. Tomato transgenic plants expressing hairpin construct of a nematode protease gene conferred enhanced resistance to root-knot nematodes

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Dutta

    2015-04-01

    Full Text Available Root-knot nematodes (Meloidogyne incognita cause substantial yield losses in vegetables worldwide, and are difficult to manage. Continuous withdrawal of environmentally-harmful nematicides from the global market warrants the need for novel nematode management strategies. Utility of host-delivered RNAi has been demonstrated in several plants (Arabidopsis, tobacco and soybean that exhibited resistance against root-knot and cyst nematodes. Herein, a M. incognita-specific protease gene, cathepsin L cysteine proteinase (Mi-cpl-1, was targeted to generate tomato transgenic lines to evaluate the genetically modified nematode resistance. In vitro knockdown of Mi-cpl-1 gene led to the reduced attraction and penetration of M. incognita in tomato, suggesting the involvement of Mi-cpl-1 in nematode parasitism. Transgenic expression of the RNAi construct of Mi-cpl-1 gene resulted in 60-80% reduction in infection and multiplication of M. incognita in tomato. Evidence for in vitro and in vivo silencing of Mi-cpl-1 was confirmed by expression analysis using quantitative PCR. Our study demonstrates that Mi-cpl-1 plays crucial role during plant-nematode interaction and plant-mediated downregulation of this gene elicits detrimental effect on M. incognita development, reinforcing the potential of RNAi technology for management of phytonematodes in crop plants.

  2. Relationship between Psidium species (Myrtaceae) by resistance gene analog markers: focus on nematode resistance.

    Science.gov (United States)

    Noia, L R; Tuler, A C; Ferreira, A; Ferreira, M F S

    2017-03-16

    Guava (Psidium guajava L.) crop is severely affected by the nematode Meloidogyne enterolobii. Native Psidium species have been reported as sources of resistance against this nematode. Knowledge on the molecular relationship between Psidium species based on plant resistance gene analogs (RGA) can be useful in the genetic breeding of guava for resistance to M. enterolobii. In this study, RGA markers from conserved domains, and structural features of plant R genes, were employed to characterize Psidium species and establish genetic proximity, with a focus on nematode resistance. SSR markers were also applied owing to their neutral nature, thus differing from RGA markers. For this, species reported as sources of resistance to M. enterolobii, such as P. cattleianum and P. friedrichsthalianum, as well as species occurring in the Atlantic Rainforest and susceptible genotypes, were investigated. In 10 evaluated Psidium species, high interspecific genetic variability was verified through RGA and SSR markers, with intraspecific variation in P. guajava higher with SSR, as was expected. Resistant species were clustered by RGA markers, and differential amplicons among genotypes resistant and susceptible to M. enterolobii were identified. Knowledge on the molecular relationships between Psidium species constitutes useful information for breeding of the guava tree, providing direction for hybridization and material for rootstocks. Additionally, the genetic relationship between native species, which have been little studied, and P. guajava were estimated by RGAs, which were confirmed as important markers for genetic diversity related to pathogen resistance.

  3. Functionality of resistance gene Hero, which controls plant root-infecting potato cyst nematodes, in leaves of tomato.

    Science.gov (United States)

    Poch, H L Cabrera; López, R H Manzanilla; Kanyuka, K

    2006-07-01

    The expression of host genomes is modified locally by root endoparasitic nematode secretions to induce the development of complex cellular structures referred as feeding sites. In compatible interactions, the feeding sites provide the environment and nutrients for the completion of the nematode's life cycle, whereas in an incompatible (resistant) interaction, the host immune system triggers a plant cell death programme, often in the form of a hypersensitive reaction, which restricts nematode reproduction. These processes have been studied in great detail in organ tissues normally infected by these nematodes: the roots. Here we show that host leaves can support a similar set of programmed developmental events in the potato cyst nematode Globodera rostochiensis life cycle that are typical of the root-invading nematodes. We also show that a gene-for-gene type specific disease resistance that is effective against potato cyst nematodes (PCN) in roots also operates in leaves: the expression of the resistance (R) gene Hero and members of its gene family in leaves correlates with the elicitation of a hypersensitive response only during the incompatible interaction. These findings, and the ability to isolate RNA from relevant parasitic stages of the nematode, may have significant implications for the identification of nematode factors involved in incompatible interactions.

  4. Pyramiding, alternating or mixing: comparative performances of deployment strategies of nematode resistance genes to promote plant resistance efficiency and durability.

    Science.gov (United States)

    Djian-Caporalino, Caroline; Palloix, Alain; Fazari, Ariane; Marteu, Nathalie; Barbary, Arnaud; Abad, Pierre; Sage-Palloix, Anne-Marie; Mateille, Thierry; Risso, Sabine; Lanza, Roger; Taussig, Catherine; Castagnone-Sereno, Philippe

    2014-02-22

    Resistant cultivars are key elements for pathogen control and pesticide reduction, but their repeated use may lead to the emergence of virulent pathogen populations, able to overcome the resistance. Increased research efforts, mainly based on theoretical studies, explore spatio-temporal deployment strategies of resistance genes in order to maximize their durability. We evaluated experimentally three of these strategies to control root-knot nematodes: cultivar mixtures, alternating and pyramiding resistance genes, under controlled and field conditions over a 3-years period, assessing the efficiency and the durability of resistance in a protected crop rotation system with pepper as summer crop and lettuce as winter crop. The choice of the resistance gene and the genetic background in which it is introgressed, affected the frequency of resistance breakdown. The pyramiding of two different resistance genes in one genotype suppressed the emergence of virulent isolates. Alternating different resistance genes in rotation was also efficient to decrease virulent populations in fields due to the specificity of the virulence and the trapping effect of resistant plants. Mixing resistant cultivars together appeared as a less efficient strategy to control nematodes. This work provides experimental evidence that, in a cropping system with seasonal sequences of vegetable species, pyramiding or alternating resistance genes benefit yields in the long-term by increasing the durability of resistant cultivars and improving the long-term control of a soil-borne pest. To our knowledge, this result is the first one obtained for a plant-nematode interaction, which helps demonstrate the general applicability of such strategies for breeding and sustainable management of resistant cultivars against pathogens.

  5. Identification of virus and nematode resistance genes in the Chilota Potato Genebank of the Universidad Austral de Chile

    Directory of Open Access Journals (Sweden)

    Marlon López

    2015-09-01

    Full Text Available Potato Genebank of the Universidad Austral de Chile (UACh is an important gene bank in Chile. The accessions collected all over the country possess high genetic diversity, present interesting agronomic and cooking traits, and show resistance to biotic and abiotic stress. A particularly interesting subgroup of the gene bank includes the accessions collected in the South of Chile, the Chilota Potato Genebank. The focus of this study is the identification of virus and nematode resistant genes in potatoes (Solatium tuberosum L., using the RYSC3 and YES3-3B molecular markers. The Potato virus Y(PVY resistance genes Ry adg and Ry sto were identified. Furthermore, the CP60 marker was used to assess the Rx resistance gene that confers resistance to Potato virus X (PVX. In addition, the HC and GRO1-4 markers were utilized to identify the GpaVvrn_QTL and Gro1-4, resistance genes of Globodera pallida and Globodera rostochiensis, respectively. Both G. pallida and G. rostochiensis are Potato Cyst Nematodes (PCN. The plant material used in this study included leaves from 271 accessions of the gene bank. These samples were collected in the field where natural pathogen pressure of potential viruses and diseases exists. ELISA assays were run for field detection of PVY and PVX. However, there have been no previous reports of nematode presence in the plant material. The results herein presented indicate presence of virus and nematode resistance genes in accessions of the Chilota Potato Genebank. In terms of virus resistance, 99 accessions out of the 271 tested possess the Ry adg resistance gene and 17 accessions of these 271 tested have the Ry sto resistance gene. Also, 10 accessions showed positive amplification of the Rxl resistant gene marker. As to nematode resistance, 99 accessions have possible resistance to G. pallida and 54 accessions show potential resistance to G. rostochiensis as detected using the available molecular markers.

  6. QTL mapping and transcriptome analysis of cowpea reveals candidate genes for root-knot nematode resistance.

    Science.gov (United States)

    Santos, Jansen Rodrigo Pereira; Ndeve, Arsenio Daniel; Huynh, Bao-Lam; Matthews, William Charles; Roberts, Philip Alan

    2018-01-01

    Cowpea is one of the most important food and forage legumes in drier regions of the tropics and subtropics. However, cowpea yield worldwide is markedly below the known potential due to abiotic and biotic stresses, including parasitism by root-knot nematodes (Meloidogyne spp., RKN). Two resistance genes with dominant effect, Rk and Rk2, have been reported to provide resistance against RKN in cowpea. Despite their description and use in breeding for resistance to RKN and particularly genetic mapping of the Rk locus, the exact genes conferring resistance to RKN remain unknown. In the present work, QTL mapping using recombinant inbred line (RIL) population 524B x IT84S-2049 segregating for a newly mapped locus and analysis of the transcriptome changes in two cowpea near-isogenic lines (NIL) were used to identify candidate genes for Rk and the newly mapped locus. A major QTL, designated QRk-vu9.1, associated with resistance to Meloidogyne javanica reproduction, was detected and mapped on linkage group LG9 at position 13.37 cM using egg production data. Transcriptome analysis on resistant and susceptible NILs 3 and 9 days after inoculation revealed up-regulation of 109 and 98 genes and down-regulation of 110 and 89 genes, respectively, out of 19,922 unique genes mapped to the common bean reference genome. Among the differentially expressed genes, four and nine genes were found within the QRk-vu9.1 and QRk-vu11.1 QTL intervals, respectively. Six of these genes belong to the TIR-NBS-LRR family of resistance genes and three were upregulated at one or more time-points. Quantitative RT-PCR validated gene expression to be positively correlated with RNA-seq expression pattern for eight genes. Future functional analysis of these cowpea genes will enhance our understanding of Rk-mediated resistance and identify the specific gene responsible for the resistance.

  7. QTL mapping and transcriptome analysis of cowpea reveals candidate genes for root-knot nematode resistance.

    Directory of Open Access Journals (Sweden)

    Jansen Rodrigo Pereira Santos

    Full Text Available Cowpea is one of the most important food and forage legumes in drier regions of the tropics and subtropics. However, cowpea yield worldwide is markedly below the known potential due to abiotic and biotic stresses, including parasitism by root-knot nematodes (Meloidogyne spp., RKN. Two resistance genes with dominant effect, Rk and Rk2, have been reported to provide resistance against RKN in cowpea. Despite their description and use in breeding for resistance to RKN and particularly genetic mapping of the Rk locus, the exact genes conferring resistance to RKN remain unknown. In the present work, QTL mapping using recombinant inbred line (RIL population 524B x IT84S-2049 segregating for a newly mapped locus and analysis of the transcriptome changes in two cowpea near-isogenic lines (NIL were used to identify candidate genes for Rk and the newly mapped locus. A major QTL, designated QRk-vu9.1, associated with resistance to Meloidogyne javanica reproduction, was detected and mapped on linkage group LG9 at position 13.37 cM using egg production data. Transcriptome analysis on resistant and susceptible NILs 3 and 9 days after inoculation revealed up-regulation of 109 and 98 genes and down-regulation of 110 and 89 genes, respectively, out of 19,922 unique genes mapped to the common bean reference genome. Among the differentially expressed genes, four and nine genes were found within the QRk-vu9.1 and QRk-vu11.1 QTL intervals, respectively. Six of these genes belong to the TIR-NBS-LRR family of resistance genes and three were upregulated at one or more time-points. Quantitative RT-PCR validated gene expression to be positively correlated with RNA-seq expression pattern for eight genes. Future functional analysis of these cowpea genes will enhance our understanding of Rk-mediated resistance and identify the specific gene responsible for the resistance.

  8. Loci and candidate genes conferring resistance to soybean cyst nematode HG type 2.5.7.

    Science.gov (United States)

    Zhao, Xue; Teng, Weili; Li, Yinghui; Liu, Dongyuan; Cao, Guanglu; Li, Dongmei; Qiu, Lijuan; Zheng, Hongkun; Han, Yingpeng; Li, Wenbin

    2017-06-14

    Soybean (Glycine max L. Merr.) cyst nematode (SCN, Heterodera glycines I,) is a major pest of soybean worldwide. The most effective strategy to control this pest involves the use of resistant cultivars. The aim of the present study was to investigate the genome-wide genetic architecture of resistance to SCN HG Type 2.5.7 (race 1) in landrace and elite cultivated soybeans. A total of 200 diverse soybean accessions were screened for resistance to SCN HG Type 2.5.7 and genotyped through sequencing using the Specific Locus Amplified Fragment Sequencing (SLAF-seq) approach with a 6.14-fold average sequencing depth. A total of 33,194 SNPs were identified with minor allele frequencies (MAF) over 4%, covering 97% of all the genotypes. Genome-wide association mapping (GWAS) revealed thirteen SNPs associated with resistance to SCN HG Type 2.5.7. These SNPs were distributed on five chromosomes (Chr), including Chr7, 8, 14, 15 and 18. Four SNPs were novel resistance loci and nine SNPs were located near known QTL. A total of 30 genes were identified as candidate genes underlying SCN resistance. A total of sixteen novel soybean accessions were identified with significant resistance to HG Type 2.5.7. The beneficial alleles and candidate genes identified by GWAS might be valuable for improving marker-assisted breeding efficiency and exploring the molecular mechanisms underlying SCN resistance.

  9. Sequence Exchange between Homologous NB-LRR Genes Converts Virus Resistance into Nematode Resistance, and Vice Versa.

    Science.gov (United States)

    Slootweg, Erik; Koropacka, Kamila; Roosien, Jan; Dees, Robert; Overmars, Hein; Lankhorst, Rene Klein; van Schaik, Casper; Pomp, Rikus; Bouwman, Liesbeth; Helder, Johannes; Schots, Arjen; Bakker, Jaap; Smant, Geert; Goverse, Aska

    2017-09-01

    Plants have evolved a limited repertoire of NB-LRR disease resistance ( R ) genes to protect themselves against myriad pathogens. This limitation is thought to be counterbalanced by the rapid evolution of NB-LRR proteins, as only a few sequence changes have been shown to be sufficient to alter resistance specificities toward novel strains of a pathogen. However, little is known about the flexibility of NB-LRR R genes to switch resistance specificities between phylogenetically unrelated pathogens. To investigate this, we created domain swaps between the close homologs Gpa2 and Rx1 , which confer resistance in potato ( Solanum tuberosum ) to the cyst nematode Globodera pallida and Potato virus X , respectively. The genetic fusion of the CC-NB-ARC of Gpa2 with the LRR of Rx1 (Gpa2 CN /Rx1 L ) results in autoactivity, but lowering the protein levels restored its specific activation response, including extreme resistance to Potato virus X in potato shoots. The reciprocal chimera (Rx1 CN /Gpa2 L ) shows a loss-of-function phenotype, but exchange of the first three LRRs of Gpa2 by the corresponding region of Rx1 was sufficient to regain a wild-type resistance response to G. pallida in the roots. These data demonstrate that exchanging the recognition moiety in the LRR is sufficient to convert extreme virus resistance in the leaves into mild nematode resistance in the roots, and vice versa. In addition, we show that the CC-NB-ARC can operate independently of the recognition specificities defined by the LRR domain, either aboveground or belowground. These data show the versatility of NB-LRR genes to generate resistance to unrelated pathogens with completely different lifestyles and routes of invasion. © 2017 American Society of Plant Biologists. All Rights Reserved.

  10. Characterization of Soybean WRKY Gene Family and Identification of Soybean WRKY Genes that Promote Resistance to Soybean Cyst Nematode.

    Science.gov (United States)

    Yang, Yan; Zhou, Yuan; Chi, Yingjun; Fan, Baofang; Chen, Zhixiang

    2017-12-19

    WRKY proteins are a superfamily of plant transcription factors with important roles in plants. WRKY proteins have been extensively analyzed in plant species including Arabidopsis and rice. Here we report characterization of soybean WRKY gene family and their functional analysis in resistance to soybean cyst nematode (SCN), the most important soybean pathogen. Through search of the soybean genome, we identified 174 genes encoding WRKY proteins that can be classified into seven groups as established in other plants. WRKY variants including a WRKY-related protein unique to legumes have also been identified. Expression analysis reveals both diverse expression patterns in different soybean tissues and preferential expression of specific WRKY groups in certain tissues. Furthermore, a large number of soybean WRKY genes were responsive to salicylic acid. To identify soybean WRKY genes that promote soybean resistance to SCN, we first screened soybean WRKY genes for enhancing SCN resistance when over-expressed in transgenic soybean hairy roots. To confirm the results, we transformed five WRKY genes into a SCN-susceptible soybean cultivar and generated transgenic soybean lines. Transgenic soybean lines overexpressing three WRKY transgenes displayed increased resistance to SCN. Thus, WRKY genes could be explored to develop new soybean cultivars with enhanced resistance to SCN.

  11. The expression of R genes in genetic and induced resistance to potato cyst nematode Globodera rostochiensis (Wollenweber, 1923) Behrens, 1975.

    Science.gov (United States)

    Lavrova, V V; Matveeva, E M; Zinovieva, S V

    2015-01-01

    The characteristics of expression of two genes, H1 and Gro1-4, which determine the resistance to the sedentary parasitic nematode Globodera rostochiensis (Wollenweber, 1923) Behrens, 1975, in the resistant (Krepysh) and susceptible (Nevskii) potato cultivars was studied under a short-term exposure to low temperatures. Such treatment of susceptible plants at the early stages of ontogeny led to the activation of expression of H1 and Gro1-4 genes in roots and the H1 gene in leaves. The transcriptional activity of R genes was detected not only in roots but also in leaves (i.e., in tissue remote from the site of direct injury by the nematode) in the case of both genetic and induced resistance, indicating the development of a systemic defense response of plants to infection.

  12. Effects of Php Gene-Associated versus Induced Resistance to Tobacco Cyst Nematode in Flue-Cured Tobacco

    Science.gov (United States)

    Johnson, Charles S.; Eisenback, Jon D.

    2009-01-01

    Effects of the systemic acquired resistance (SAR)-inducing compound acibenzolar-S-methyl (ASM) and the plant-growth promoting rhizobacterial mixture Bacillus subtilis A13 and B. amyloliquefaciens IN937a (GB99+GB122) were assessed on the reproduction of a tobacco cyst nematode (TCN- Globodera tabacum solanacearum) under greenhouse conditions. Two sets of two independent experiments were conducted, each involving soil or root sampling. Soil sample experiments included flue-cured tobacco cultivars with (Php+: NC71 and NC102) and without (Php-: K326 and K346) a gene (Php) suppressing TCN parasitism. Root sample experiments examined TCN root parasitism of NC71 and K326. Cultivars possessing the Php gene (Php+) were compared with Php- cultivars to assess the effects of resistance mediated via Php gene vs. induced resistance to TCN. GB99+GB122 consistently reduced nematode reproductive ratio on both Php+ and Php- cultivars, but similar effects of ASM across Php- cultivars were less consistent. In addition, ASM application resulted in leaf yellowing and reduced root weight. GB99+GB122 consistently reduced nematode development in roots of both Php+ and Php- cultivars, while similar effects of ASM were frequently less consistent. The results of this study indicate that GB99+GB122 consistently reduced TCN reproduction in all flue-cured tobacco cultivars tested, while the effects of ASM were only consistent in Php+ cultivars. Under most circumstances, GB99+GB122 suppressed nematode reproduction more consistently than ASM compared to the untreated control. PMID:22736824

  13. Cereal cyst nematode resistance conferred by the Cre7 gene from Aegilops triuncialis and its relationship with Cre genes from Australian wheat cultivars

    OpenAIRE

    Montes, Maria Jesus; Andrés, María Fe; Sin, E.; Lopez Braña, Isidoro; Martín-Sánchez, J.A.; Romero, M.D.; Delibes Castro, Angeles

    2008-01-01

    Cereal cyst nematode (CCN; Heterodera avenae Woll.) is a root pathogen of cereal crops that can cause severe yield losses in wheat (Triticum aestivum). Differential host–nematode interactions occur in wheat cultivars carrying different CCN resistance (Cre) genes. The objective of this study was to determine the CCN resistance conferred by the Cre7 gene from Aegilops triuncialis in a 42-chromosome introgression line and to assess the effects of the Cre1, Cre3, Cre4, and Cre8 genes present in A...

  14. Overexpression of a soybean salicylic acid methlyltransferase gene confers resistance to soybean cyst nematode

    Science.gov (United States)

    Soybean cyst nematode (Heterodera glycines Ichinohe, SCN) is the most pervasive pest of soybean [Glycine max (L.) Merr.] in the USA and worldwide. SCN reduced soybean yields worldwide by an estimated billion dollars annually. These losses remained stable with the use of resistant cultivars but over ...

  15. Engineered resistance and hypersusceptibility through functional metabolic studies of 100 genes in soybean to its major pathogen, the soybean cyst nematode.

    Science.gov (United States)

    Matthews, Benjamin F; Beard, Hunter; MacDonald, Margaret H; Kabir, Sara; Youssef, Reham M; Hosseini, Parsa; Brewer, Eric

    2013-05-01

    During pathogen attack, the host plant induces genes to ward off the pathogen while the pathogen often produces effector proteins to increase susceptibility of the host. Gene expression studies of syncytia formed in soybean root by soybean cyst nematode (Heterodera glycines) identified many genes altered in expression in resistant and susceptible roots. However, it is difficult to assess the role and impact of these genes on resistance using gene expression patterns alone. We selected 100 soybean genes from published microarray studies and individually overexpressed them in soybean roots to determine their impact on cyst nematode development. Nine genes reduced the number of mature females by more than 50 % when overexpressed, including genes encoding ascorbate peroxidase, β-1,4-endoglucanase, short chain dehydrogenase, lipase, DREPP membrane protein, calmodulin, and three proteins of unknown function. One gene encoding a serine hydroxymethyltransferase decreased the number of mature cyst nematode females by 45 % and is located at the Rhg4 locus. Four genes increased the number of mature cyst nematode females by more than 200 %, while thirteen others increased the number of mature cyst nematode females by more than 150 %. Our data support a role for auxin and ethylene in susceptibility of soybean to cyst nematodes. These studies highlight the contrasting gene sets induced by host and nematode during infection and provide new insights into the interactions between host and pathogen at the molecular level. Overexpression of some of these genes result in a greater decrease in the number of cysts formed than recognized soybean cyst nematode resistance loci.

  16. Genetic and physical mapping of homologues of the virus resistance gene Rx1 and the cyst nematode resistance gene Gpa2 in potato.

    Science.gov (United States)

    Bakker, E; Butterbach, P; Rouppe van der Voort, J; van der Vossen, E; van Vliet, J; Bakker, J; Goverse, A

    2003-05-01

    Nine resistance gene homologues (RGHs) were identified in two diploid potato clones (SH and RH), with a specific primer pair based on conserved motifs in the LRR domain of the potato cyst nematode resistance gene Gpa2 and the potato virus X resistance gene Rx1. A modified AFLP method was used to facilitate the genetic mapping of the RGHs in the four haplotypes under investigation. All nine RGHs appeared to be located in the Gpa2/ Rx1 cluster on chromosome XII. Construction of a physical map using bacterial artificial chromosome (BAC) clones for both the Solanum tuberosum ssp. tuberosum and the S. tuberosum ssp. andigena haplotype of SH showed that the RGHs are located within a stretch of less than 200 kb. Sequence analysis of the RGHs revealed that they are highly similar (93 to 95%) to Gpa2 and Rx1. The sequence identities among all RGHs range from 85 to 100%. Two pairs of RGHs are identical, or nearly so (100 and 99.9%), with each member located in a different genotype. Southern-blot analysis on genomic DNA revealed no evidence for additional homologues outside the Gpa2/ Rx1 cluster on chromosome XII.

  17. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

    Directory of Open Access Journals (Sweden)

    Silvestre A.

    2004-06-01

    Full Text Available In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control ? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole. Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial : it is not possible to avoid it, but only to delay its development in farm animal industry.

  18. Transgenic Strategies for Enhancement of Nematode Resistance in Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-05-01

    Full Text Available Plant parasitic nematodes (PPNs are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

  19. DNA sequences from two SSRs (CIR316 and MUCS088) linked to root-knot nematode resistance genes from diverse cottons (Gossypium spp).

    Science.gov (United States)

    We investigated DNA sequencing information from alleles (DNA amplified fragments) of two previously reported SSR markers (CIR316 and MUCS088) linked to root-knot nematode (RKN) resistance genes. Markers based on electrophoretic differences, including RFLPs, AFLPs and SSRs can sometimes mask underlyi...

  20. Anthelmintic resistance in equine nematodes

    Directory of Open Access Journals (Sweden)

    Jacqueline B. Matthews

    2014-12-01

    Full Text Available Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole, tetrahydropyrimidines (pyrantel and macrocyclic lactones (ivermectin, moxidectin. Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop

  1. Molecular cloning of the potato Gro1-4 gene conferring resistance to pathotype Ro1 of the root cyst nematode Globodera rostochiensis, based on a candidate gene approach.

    Science.gov (United States)

    Paal, Jürgen; Henselewski, Heike; Muth, Jost; Meksem, Khalid; Menéndez, Cristina M; Salamini, Francesco; Ballvora, Agim; Gebhardt, Christiane

    2004-04-01

    The endoparasitic root cyst nematode Globodera rostochiensis causes considerable damage in potato cultivation. In the past, major genes for nematode resistance have been introgressed from related potato species into cultivars. Elucidating the molecular basis of resistance will contribute to the understanding of nematode-plant interactions and assist in breeding nematode-resistant cultivars. The Gro1 resistance locus to G. rostochiensis on potato chromosome VII co-localized with a resistance-gene-like (RGL) DNA marker. This marker was used to isolate from genomic libraries 15 members of a closely related candidate gene family. Analysis of inheritance, linkage mapping, and sequencing reduced the number of candidate genes to three. Complementation analysis by stable potato transformation showed that the gene Gro1-4 conferred resistance to G. rostochiensis pathotype Ro1. Gro1-4 encodes a protein of 1136 amino acids that contains Toll-interleukin 1 receptor (TIR), nucleotide-binding (NB), leucine-rich repeat (LRR) homology domains and a C-terminal domain with unknown function. The deduced Gro1-4 protein differed by 29 amino acid changes from susceptible members of the Gro1 gene family. Sequence characterization of 13 members of the Gro1 gene family revealed putative regulatory elements and a variable microsatellite in the promoter region, insertion of a retrotransposon-like element in the first intron, and a stop codon in the NB coding region of some genes. Sequence analysis of RT-PCR products showed that Gro1-4 is expressed, among other members of the family including putative pseudogenes, in non-infected roots of nematode-resistant plants. RT-PCR also demonstrated that members of the Gro1 gene family are expressed in most potato tissues.

  2. Trehalose metabolism genes render rice white tip nematode Aphelenchoides besseyi (Nematoda: Aphelenchoididae) resistant to an anaerobic environment

    Science.gov (United States)

    Chen, Qiaoli; Zhang, Ruizhi; Ling, Yaming

    2018-01-01

    ABSTRACT After experiencing anaerobic environments, Aphelenchoides besseyi will enter a state of suspended animation known as anoxybiosis, during which it may use trehalose as an energy supply to survive. To explore the function of trehalose metabolism, two trehalose-6-phosphate synthase (TPS) genes (Ab-tps1 and Ab-tps2) encoding enzymes catalysing trehalose synthesis, and three trehalase (TRE) genes (Ab-ntre1, Ab-ntre2 and Ab-atre) encoding enzymes catalysing the hydrolysis of trehalose, were identified and investigated. Ab-tps1 and Ab-tps2 were active during certain periods of anoxybiosis for A. besseyi, and Ab-tps2, Ab-ntre1, Ab-ntre2 and Ab-atre were active during certain periods of recovery. The results of RNA interference experiments suggested that TRE genes regulated each other and both TPS genes, while a single TPS gene only regulated the other TPS gene. However, two TPS genes together could regulate TRE genes, which indicated a feedback mechanism between these genes. All these genes also positively regulated the survival and resumption of active metabolism of the nematode. Genes functioning at re-aeration have a greater impact on nematode survival, suggesting that these genes could play roles in anoxybiosis regulation, but may function within restricted time frames. Changes in trehalose levels matched changes in TRE activity during the anoxybiosis–re-aeration process, suggesting that trehalose may act as an energy supply source. The observation of up-regulation of TPS genes during anoxybiosis suggested a possible signal role of trehalose. Trehalose metabolism genes could also work together to control trehalose levels at a certain level when the nematode is under anaerobic conditions. PMID:29158222

  3. Characterization of susceptibility and resistance responses to potato cyst nematode (Globodera spp.) infection of tomato lines in the absence and presence of the broad-spectrum nematode resistance Hero gene.

    Science.gov (United States)

    Sobczak, Miroslaw; Avrova, Anna; Jupowicz, Justyna; Phillips, Mark S; Ernst, Karin; Kumar, Amar

    2005-02-01

    The tomato Hero A gene is the only member of a multigene family that confers a high level (>80%) of resistance to all the economically important pathotypes of potato cyst nematode (PCN) species Globodera rostochiensis and G. pallida. Although the resistance levels of transgenic tomato lines were similar to those of the tomato line LA1792 containing the introgressed Hero multigene family, transgenic potato plants expressing the tomato Hero A gene are not resistant to PCNs. Comparative microscopy studies of in vitro infected roots of PCN-susceptible tomato cv. Money Maker, the resistant breeding line LA1792, and transgenic line L10 with Ro1 pathotype have revealed no statistically significant difference in the number of juveniles invading roots. However, syncytia (specialized feeding cells) induced in LA1792 and L10 roots mostly were found to have degenerated a few days after their induction, and a few surviving syncytia were able to support only the development of males rather than females. Thus, the ratio between males and females was biased towards males on LA1792 and L10 roots. A series of changes occur in resistant plants leading to formation of a layer of necrotic cells separating the syncytium from stellar conductive tissues and this is followed by degradation of the syncytium. Although the Hero A gene is expressed in all tissues, including roots, stems, leaves, and flower buds, its expression is upregulated in roots in response to PCN infection. Moreover, the expression profiles of the Hero A correlates with the timing of death of the syncytium.

  4. [Allelic state of the molecular marker for the golden nematode (Globodera rostochiensis) resistance gene H1 among Ukrainian and world cultivars of potato (Solanum tuberosum ssp. tuberosum)].

    Science.gov (United States)

    Karelov, A V; Pilipenko, L A; Kozub, N A; Bondus, R A; Borzykh, A U; Sozinov, I A; Blium, Ia B; Sozinov, A A

    2013-01-01

    The purpose of our investigation was determination of allelic state of the H1 resistance gene against the pathotypes Ro1 and Ro4 of golden potato cyst nematode (Globodera rostochiensis) among Ukrainian and world potato (Solanum tuberosum ssp. tuberosum) cultivars. The allelic condition of the TG689 marker was determined by PCR with DNA samples isolated from tubers of potato and primers, one pair of which flanks the allele-specific region and the other one was used for the control of DNA quality. Among analyzed 77 potato cultivars the allele of marker associated with the H1-type resistance was found in 74% of Ukrainian and 90% foreign ones although some of those cultivars proved to be susceptible to the golden potato nematode in field. The obtained data confirm the presence of H1-resistance against golden nematode pathotypes Ro1 and Ro4 among the Ukrainian potato cultivars and efficiency of the used marker within the accuracy that has been declared by its authors.

  5. Overexpression of a soybean salicylic acid methyltransferase gene confers resistance to soybean cyst nematode

    Science.gov (United States)

    Salicylic acid plays a critical role in activating plant defence responses after pathogen attack. Salicylic acid methyltransferase (SAMT) modulates the level of salicylic acid by converting salicylic acid to methyl salicylate. Here, we report that a SAMT gene from soybean (GmSAMT1) plays a role in s...

  6. Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses

    DEFF Research Database (Denmark)

    Shukla, Neha; Yadav, Rachita; Kaur, Pritam

    2017-01-01

    Root knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites having a wide-host range. We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible p...

  7. Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses

    DEFF Research Database (Denmark)

    Shukla, Neha; Yadav, Rachita; Kaur, Pritam

    2018-01-01

    Root knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites having a wide-host range. We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible p...

  8. Overexpression of MIC-3 indicates a direct role for the MIC gene family in mediating Upland cotton (Gossypium hirsutum) resistance to root-knot nematode (Meloidogyne incognita)

    Science.gov (United States)

    Major quantitative trait loci (QTL) have been mapped to Upland cotton (Gossypium hirsutum L.) chromosomes 11 and 14 that govern the highly resistant phenotype in response to infection by root-knot nematode (RKN; Meloidogyne incognita Chitwood & White); however, nearly nothing is known regarding the ...

  9. RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes

    Directory of Open Access Journals (Sweden)

    Sagar Banerjee

    2017-05-01

    Full Text Available Plant parasitic nematodes cause severe damage and yield loss in major crops all over the world. Available control strategies include use of insecticides/nematicides but these have proved detrimental to the environment, while other strategies like crop rotation and resistant cultivars have serious limitations. This scenario provides an opportunity for the utilization of technological advances like RNA interference (RNAi to engineer resistance against these devastating parasites. First demonstrated in the model free living nematode, Caenorhabtidis elegans; the phenomenon of RNAi has been successfully used to suppress essential genes of plant parasitic nematodes involved in parasitism, nematode development and mRNA metabolism. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant parasitic nematodes with significant success. However, host delivered in planta RNAi has proved to be a pioneering phenomenon to deliver dsRNAs to feeding nematodes and silence the target genes to achieve resistance. Highly enriched genomic databases are exploited to limit off target effects and ensure sequence specific silencing. Technological advances like gene stacking and use of nematode inducible and tissue specific promoters can further enhance the utility of RNAi based transgenics against plant parasitic nematodes.

  10. Arabidopsis genes, AtNPR1, AtTGA2 and AtPR-5, confer partial resistance to soybean cyst nematode (Heterodera glycines) when overexpressed in transgenic soybean roots.

    Science.gov (United States)

    Matthews, Benjamin F; Beard, Hunter; Brewer, Eric; Kabir, Sara; MacDonald, Margaret H; Youssef, Reham M

    2014-04-16

    Extensive studies using the model system Arabidopsis thaliana to elucidate plant defense signaling and pathway networks indicate that salicylic acid (SA) is the key hormone triggering the plant defense response against biotrophic and hemi-biotrophic pathogens, while jasmonic acid (JA) and derivatives are critical to the defense response against necrotrophic pathogens. Several reports demonstrate that SA limits nematode reproduction. Here we translate knowledge gained from studies using Arabidopsis to soybean. The ability of thirty-one Arabidopsis genes encoding important components of SA and JA synthesis and signaling in conferring resistance to soybean cyst nematode (SCN: Heterodera glycines) are investigated. We demonstrate that overexpression of three of thirty-one Arabidoposis genes in transgenic soybean roots of composite plants decreased the number of cysts formed by SCN to less than 50% of those found on control roots, namely AtNPR1(33%), AtTGA2 (38%), and AtPR-5 (38%). Three additional Arabidopsis genes decreased the number of SCN cysts by 40% or more: AtACBP3 (53% of the control value), AtACD2 (55%), and AtCM-3 (57%). Other genes having less or no effect included AtEDS5 (77%), AtNDR1 (82%), AtEDS1 (107%), and AtPR-1 (80%), as compared to control. Overexpression of AtDND1 greatly increased susceptibility as indicated by a large increase in the number of SCN cysts (175% of control). Knowledge of the pathogen defense system gained from studies of the model system, Arabidopsis, can be directly translated to soybean through direct overexpression of Arabidopsis genes. When the genes, AtNPR1, AtGA2, and AtPR-5, encoding specific components involved in SA regulation, synthesis, and signaling, are overexpressed in soybean roots, resistance to SCN is enhanced. This demonstrates functional compatibility of some Arabidopsis genes with soybean and identifies genes that may be used to engineer resistance to nematodes.

  11. Molecular and genetic analyses of potato cyst nematode resistance loci

    NARCIS (Netherlands)

    Bakker, E.H.

    2003-01-01

    This thesis describes the genomic localisation and organisation of loci that harbour resistance to the potato cyst nematode species Globodera pallida and G. rostochiensis . Resistance to the potato cyst nematodes G. pallida and G. rostochiensis is an important aspect in potato breeding. To gain

  12. Identification, Validation and Utilization of Novel Nematode-Responsive Root-Specific Promoters in Arabidopsis for Inducing Host-Delivered RNAi Mediated Root-Knot Nematode Resistance

    Directory of Open Access Journals (Sweden)

    Atul Kakrana

    2017-12-01

    Full Text Available The root-knot nematode (RKN, Meloidogyne incognita, is an obligate, sedentary endoparasite that infects a large number of crops and severely affects productivity. The commonly used nematode control strategies have their own limitations. Of late, RNA interference (RNAi has become a popular approach for the development of nematode resistance in plants. Transgenic crops capable of expressing dsRNAs, specifically in roots for disrupting the parasitic process, offer an effective and efficient means of producing resistant crops. We identified nematode-responsive and root-specific (NRRS promoters by using microarray data from the public domain and known conserved cis-elements. A set of 51 NRRS genes was identified which was narrowed down further on the basis of presence of cis-elements combined with minimal expression in the absence of nematode infection. The comparative analysis of promoters from the enriched NRRS set, along with earlier reported nematode-responsive genes, led to the identification of specific cis-elements. The promoters of two candidate genes were used to generate transgenic plants harboring promoter GUS constructs and tested in planta against nematodes. Both promoters showed preferential expression upon nematode infection, exclusively in the root in one and galls in the other. One of these NRRS promoters was used to drive the expression of splicing factor, a nematode-specific gene, for generating host-delivered RNAi-mediated nematode-resistant plants. Transgenic lines expressing dsRNA of splicing factor under the NRRS promoter exhibited upto a 32% reduction in number of galls compared to control plants.

  13. Transcriptome analysis of resistant and susceptible alfalfa cultivars infected with root-knot nematode Meloidogyne incognita.

    Directory of Open Access Journals (Sweden)

    Olga A Postnikova

    Full Text Available Nematodes are one of the major limiting factors in alfalfa production. Root-knot nematodes (RKN, Meloidogyne spp. are widely distributed and economically important sedentary endoparasites of agricultural crops and they may inflict significant damage to alfalfa fields. As of today, no studies have been published on global gene expression profiling in alfalfa infected with RKN or any other plant parasitic nematode. Very little information is available about molecular mechanisms that contribute to pathogenesis and defense responses in alfalfa against these pests and specifically against RKN. In this work, we performed root transcriptome analysis of resistant (cv. Moapa 69 and susceptible (cv. Lahontan alfalfa cultivars infected with RKN Meloidogyne incognita, widespread root-knot nematode species and a major pest worldwide. A total of 1,701,622,580 pair-end reads were generated on an Illumina Hi-Seq 2000 platform from the roots of both cultivars and assembled into 45,595 and 47,590 transcripts in cvs Moapa 69 and Lahontan, respectively. Bioinformatic analysis revealed a number of common and unique genes that were differentially expressed in susceptible and resistant lines as a result of nematode infection. Although the susceptible cultivar showed a more pronounced defense response to the infection, feeding sites were successfully established in its roots. Characteristically, basal gene expression levels under normal conditions differed between the two cultivars as well, which may confer advantage to one of the genotypes toward resistance to nematodes. Differentially expressed genes were subsequently assigned to known Gene Ontology categories to predict their functional roles and associated biological processes. Real-time PCR validated expression changes in genes arbitrarily selected for experimental confirmation. Candidate genes that contribute to protection against M. incognita in alfalfa were proposed and alfalfa-nematode interactions with

  14. Transcriptome Analysis of Cotton (Gossypium hirsutum L. Genotypes That Are Susceptible, Resistant, and Hypersensitive to Reniform Nematode (Rotylenchulus reniformis.

    Directory of Open Access Journals (Sweden)

    Ruijuan Li

    Full Text Available Reniform nematode is a semi-endoparasitic nematode species causing significant yield loss in numerous crops, including cotton (Gossypium hirsutum L.. An RNA-sequencing analysis was conducted to measure transcript abundance in reniform nematode susceptible (DP90 & SG747, resistant (BARBREN-713, and hypersensitive (LONREN-1 genotypes of cotton (Gossypium hirsutum L. with and without reniform nematode infestation. Over 90 million trimmed high quality reads were assembled into 84,711 and 80, 353 transcripts using the G. arboreum and the G. raimondii genomes as references. Many transcripts were significantly differentially expressed between the three different genotypes both prior to and during nematode pathogenesis, including transcripts corresponding to the gene ontology categories of cell wall, hormone metabolism and signaling, redox reactions, secondary metabolism, transcriptional regulation, stress responses, and signaling. Further analysis revealed that a number of these differentially expressed transcripts mapped to the G. raimondii and/or the G. arboreum genomes within 1 megabase of quantitative trait loci that had previously been linked to reniform nematode resistance. Several resistance genes encoding proteins known to be strongly linked to pathogen perception and resistance, including LRR-like and NBS-LRR domain-containing proteins, were among the differentially expressed transcripts mapping near these quantitative trait loci. Further investigation is required to confirm a role for these transcripts in reniform nematode susceptibility, hypersensitivity, and/or resistance. This study presents the first systemic investigation of reniform nematode resistance-associated genes using different genotypes of cotton. The candidate reniform nematode resistance-associated genes identified in this study can serve as the basis for further functional analysis and aid in further development of reniform a nematode resistant cotton germplasm.

  15. Effective and specific in planta RNAi in cyst nematodes: expression interference of four parasitism genes reduces parasitic success.

    Science.gov (United States)

    Sindhu, Anoop S; Maier, Tom R; Mitchum, Melissa G; Hussey, Richard S; Davis, Eric L; Baum, Thomas J

    2009-01-01

    Cyst nematodes are highly evolved sedentary plant endoparasites that use parasitism proteins injected through the stylet into host tissues to successfully parasitize plants. These secretory proteins likely are essential for parasitism as they are involved in a variety of parasitic events leading to the establishment of specialized feeding cells required by the nematode to obtain nourishment. With the advent of RNA interference (RNAi) technology and the demonstration of host-induced gene silencing in parasites, a new strategy to control pests and pathogens has become available, particularly in root-knot nematodes. Plant host-induced silencing of cyst nematode genes so far has had only limited success but similarly should disrupt the parasitic cycle and render the host plant resistant. Additional in planta RNAi data for cyst nematodes are being provided by targeting four parasitism genes through host-induced RNAi gene silencing in transgenic Arabidopsis thaliana, which is a host for the sugar beet cyst nematode Heterodera schachtii. Here it is reported that mRNA abundances of targeted nematode genes were specifically reduced in nematodes feeding on plants expressing corresponding RNAi constructs. Furthermore, this host-induced RNAi of all four nematode parasitism genes led to a reduction in the number of mature nematode females. Although no complete resistance was observed, the reduction of developing females ranged from 23% to 64% in different RNAi lines. These observations demonstrate the relevance of the targeted parasitism genes during the nematode life cycle and, potentially more importantly, suggest that a viable level of resistance in crop plants may be accomplished in the future using this technology against cyst nematodes.

  16. Development of a sweet cherry pepper line with resistance to the southern root-knot nematode Meloidogyne incognita

    Science.gov (United States)

    The southern root-knot nematode (Meloidogyne incognita) is a major pathogen of pepper (Capsicum spp.), causing significant yield losses in heavily infected plants. The N-gene confers resistance to M. incognita, and has been successfully used to mitigate nematode damage in specific pepper varieties f...

  17. Arabidopsis genes, AtNPR1, AtTGA2 and AtPR-5, confer partial resistance to soybean cyst nematode (Heterodera glycines) when overexpressed in transgenic soybean roots

    Science.gov (United States)

    2014-01-01

    Background Extensive studies using the model system Arabidopsis thaliana to elucidate plant defense signaling and pathway networks indicate that salicylic acid (SA) is the key hormone triggering the plant defense response against biotrophic and hemi-biotrophic pathogens, while jasmonic acid (JA) and derivatives are critical to the defense response against necrotrophic pathogens. Several reports demonstrate that SA limits nematode reproduction. Results Here we translate knowledge gained from studies using Arabidopsis to soybean. The ability of thirty-one Arabidopsis genes encoding important components of SA and JA synthesis and signaling in conferring resistance to soybean cyst nematode (SCN: Heterodera glycines) are investigated. We demonstrate that overexpression of three of thirty-one Arabidoposis genes in transgenic soybean roots of composite plants decreased the number of cysts formed by SCN to less than 50% of those found on control roots, namely AtNPR1(33%), AtTGA2 (38%), and AtPR-5 (38%). Three additional Arabidopsis genes decreased the number of SCN cysts by 40% or more: AtACBP3 (53% of the control value), AtACD2 (55%), and AtCM-3 (57%). Other genes having less or no effect included AtEDS5 (77%), AtNDR1 (82%), AtEDS1 (107%), and AtPR-1 (80%), as compared to control. Overexpression of AtDND1 greatly increased susceptibility as indicated by a large increase in the number of SCN cysts (175% of control). Conclusions Knowledge of the pathogen defense system gained from studies of the model system, Arabidopsis, can be directly translated to soybean through direct overexpression of Arabidopsis genes. When the genes, AtNPR1, AtGA2, and AtPR-5, encoding specific components involved in SA regulation, synthesis, and signaling, are overexpressed in soybean roots, resistance to SCN is enhanced. This demonstrates functional compatibility of some Arabidopsis genes with soybean and identifies genes that may be used to engineer resistance to nematodes. PMID:24739302

  18. Induction of mutations for nematode resistance in tomato

    International Nuclear Information System (INIS)

    Alameddine, A.

    1976-01-01

    The objective of this work is to develop resistance to root-knot nematodes in tomato by induction, selection and utilization of the newly created resistant strains. Seeds of two varieties of tomato Lycopersicon esculentum L., namely Amcopack and Supermarmande, were subjected to various doses of gamma rays ranging from 10 Krads to 40 Krads in an effort to gain resistance to Meloidogyne incognita Chitwood, the prevalent species of nematodes in Lebanon. The variety Supermarmande seemed not to be affected by irradiation while Amcopack gained some resistance with a corresponding increase in the dose of radiation. The data suggest that in a variety like Amcopack, irradiation may stimulate resistance while in others like Supermarmande, susceptibility is not reduced with a corresponding increase of dosage. Those alterations in reaction within varieties may be due to genetic differences which allow some varieties to acquire resistance to nematodes when exposed to certain dosages, while others to suffer seriously due to sensitivity. (author)

  19. Expression of a cystatin transgene in eggplant provides resistance to root-knot nematode, Meloidogyne incognita

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar Papolu

    2016-07-01

    Full Text Available Root-knot nematodes (RKN cause substantial yield decline in eggplant and sustainable management options to minimize crop damage due to nematodes are still limited. A number of genetic engineering strategies have been developed to disrupt the successful plant-nematode interactions. Among them, delivery of proteinase inhibitors from the plant to perturb nematode development and reproduction is arguably the most effective strategy. In the present study, transgenic eggplant expressing a modified rice cystatin (OC-IΔD86 gene under the control of the root-specific promoter, TUB-1, was generated to evaluate the genetically modified nematode resistance. Five putative transformants were selected through PCR and genomic Southern blot analysis. Expression of the cystatin transgene was confirmed in all the events using western blotting, ELISA and qPCR assay. Upon challenge inoculation, all the transgenic events exhibited a detrimental effect on RKN development and reproduction. The best transgenic line (a single copy event showed 78.3% inhibition in reproductive success of RKN. Our results suggest that cystatins can play an important role for improving nematode resistance in eggplant and their deployment in gene pyramiding strategies with other proteinase inhibitors could ultimately enhance crop yield.

  20. Expression of Arabidopsis genes AtNPR1 and AtTGA2 in transgenic soybean roots of composite plants confers resistance to root-knot nematode (Meloidogyne incognita)

    Science.gov (United States)

    Root-knot nematodes (RKN; Meloidogyne spp.) are among the most destructive of the plant parasitic nematodes, infecting almost all cultivated plants and resulting in yield losses of billions of dollars annually. NPR1 (nonexpresser of pathogenesis related genes 1, AtNPR1) plays a positive role in the ...

  1. Population-specific gene expression in the plant pathogenic nematode Heterodera glycines exists prior to infection and during the onset of a resistant or susceptible reaction in the roots of the Glycine max genotype Peking

    Directory of Open Access Journals (Sweden)

    Alkharouf Nadim W

    2009-03-01

    Full Text Available Abstract Background A single Glycine max (soybean genotype (Peking reacts differently to two different populations of Heterodera glycines (soybean cyst nematode within the first twelve hours of infection during resistant (R and susceptible (S reactions. This suggested that H. glycines has population-specific gene expression signatures. A microarray analysis of 7539 probe sets representing 7431 transcripts on the Affymetrix® soybean GeneChip® were used to identify population-specific gene expression signatures in pre-infective second stage larva (pi-L2 prior to their infection of Peking. Other analyses focused on the infective L2 at 12hours post infection (i-L212h, and the infective sedentary stages at 3days post infection (i-L23d and 8days post infection (i-L2/L38d. Results Differential expression and false discovery rate (FDR analyses comparing populations of pi-L2 (i.e., incompatible population, NL1-RHg to compatible population, TN8 identified 71 genes that were induced in NL1-RHg as compared to TN8. These genes included putative gland protein G23G12, putative esophageal gland protein Hgg-20 and arginine kinase. The comparative analysis of pi-L2 identified 44 genes that were suppressed in NL1-RHg as compared to TN8. These genes included a different Hgg-20 gene, an EXPB1 protein and a cuticular collagen. By 12 h, there were 7 induced genes and 0 suppressed genes in NL1-RHg. By 3d, there were 9 induced and 10 suppressed genes in NL1-RHg. Substantial changes in gene expression became evident subsequently. At 8d there were 13 induced genes in NL1-RHg. This included putative gland protein G20E03, ubiquitin extension protein, putative gland protein G30C02 and β-1,4 endoglucanase. However, 1668 genes were found to be suppressed in NL1-RHg. These genes included steroid alpha reductase, serine proteinase and a collagen protein. Conclusion These analyses identify a genetic expression signature for these two populations both prior to and subsequently

  2. Resistance and Resistant Reaction of Gossypium arboreum to the Reniform, Nematode, Rotylenchulus reniformis

    Science.gov (United States)

    Carter, William W.

    1981-01-01

    Gossypium arboreum 'Nanking CB 1402' possessed a high level of resistance to Rotylenchulus reniformis. Within 16 h, the nematode penetrated roots of resistant and susceptible cottons equally. After 36 h, significantly fewer nematodes were found in resistant roots. Larvae fed in either an endodermal or pericyclic cell and had no specificity for root tissue of a particular age. In roots of resistant G. arboreum '1402,' wall breakdown of pericyclic cells was evident after 3 d, endodermal and cortical cells collapsed, and the hypertrophied pericyclic cells disintegrated within 12 d. Cell walls immediately adjacent to the nematode's head were thickened and more safranin positive in resistant than in susceptible cotton cultivars. Several other cultivars of G. arboreum were also resistant to R. reniformis, based on nematode fecundity and percent egg reduction. PMID:19300777

  3. Nematodes

    International Nuclear Information System (INIS)

    Suzuki, Kenshi; Ishii, Naoaki

    1977-01-01

    Utilization of nematodes for a study of radiation biology was considered. Structure, generation, rearing method, and genetic nature of nematodes (Caenorhabditis elegans, Turbatri acetic, etc.) were given an outline. As the advantage of a study using nematodes as materials, shortness of one generation time, simplicity in structure, and smallness of the whole cells, specific regular movement, and heliotaxis to chemical substances and light were mentioned. Effect of x-ray on survival rate of nematodes and effect of ultraviolet on nematodes and their eggs were described. It was suggested that nematodes was useful for studies on aging and radiation biology, and a possibility existed that nematodes would be used in studies of cancer and malformation. (Serizawa, K.)

  4. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  5. Anthelmintic resistance in cattle nematodes in the US.

    Science.gov (United States)

    Gasbarre, Louis C

    2014-07-30

    The first documented case of macrocyclic lactone resistance in gastrointestinal (GI) nematodes of cattle was seen in the US approximately 10 years ago. Since that time the increase incidence of anthelmintic resistance has continued at an alarming rate. Currently parasites of the genera Cooperia and/or Haemonchus resistant to generic or brand-name macrocyclic lactones have be demonstrated in more than half of all operations examined. Both of these parasite genera are capable of causing economic losses by decreasing food intake and subsequently animal productivity. Currently, there are no easy and quick means to detect anthelmintic resistant GI nematodes. Definitive identification requires killing of cattle. The most commonly used field detection method is the fecal egg count reduction test (FECRT). This method can be adapted for use as a screening agent for Veterinarians and producers to identify less than desired clearance of the parasites after anthelmintic treatment. Further studies can then define the reasons for persistence of the egg counts. The appearance of anthelmintic resistance is largely due to the development of very effective nematode control programs that have significantly improved the productivity of the US cattle industry, but at the same time has placed a high level of selective pressure on the parasite genome. The challenges ahead include the development of programs that control the anthelmintic resistant nematodes but at the same time result in more sustainable parasite control. The goal is to maintain high levels of productivity but to exert less selective pressures on the parasites. One of the most effective means to slow the development of drug resistance is through the simultaneous use of multiple classes of anthelmintics, each of which has a different mode of action. Reduction of the selective pressure on the parasites can be attained through a more targeted approach to drug treatments where the producer's needs are met by selective

  6. Characterization of the psoRPM1 gene for resistance to root-knot ...

    African Journals Online (AJOL)

    Several root-knot nematode (Meloidogyne spp.) resistance genes have been discovered in different stone fruit crops. However, none of them has yet been cloned and they were only located on the chromosomes. In this study, a candidate root-knot nematode resistance gene (designated as psoRPM1) was isolated from the ...

  7. A Consideration of Resistance and Tolerance for Ruminant Nematode Infections

    Directory of Open Access Journals (Sweden)

    Steve eBishop

    2012-12-01

    Full Text Available Debates on the relative merits of resistance (the ability of the host to control the parasite lifecycle and tolerance (the net impact of infection on host performance are often lively and unhindered by data or evidence. Resistance generally shows continuous, heritable variation but data are sparser for tolerance, the utility of which will depend upon the disease prevalence. Prevalence is a function of group mean resistance and infection pressure, which itself is influenced by mean resistance. Tolerance will have most value for endemic diseases with a high prevalence, but will be of little value for low prevalence diseases. The conditionality of tolerance on infection status, and hence resistance, makes it difficult to estimate independently of resistance.Tolerance is potentially tractable for nematode infections, as the prevalence of infection is ca. 100% in animals grazing infected pasture, and infection level can be quantified by faecal egg count (FEC. Whilst individual animal phenotypes for tolerance are difficult to estimate, breeding values are estimable if related animals graze pastures of different contamination levels. Selection for resistance, i.e. FEC, provides both direct and indirect benefits from ever decreased pasture contamination and hence decreased infectious challenge. Modelling and experimental studies have shown that such reductions in pasture contamination may lead to substantially increased performance.It is proposed that selection goals addressing nematode infections should include both resistance and performance under challenging conditions. However, there may be benefits from exploiting large datasets in which sires are used across cohorts differing in infection level, to further explore tolerance. This may help to customise breeding objectives, with tolerance given greater weight in heavily parasitized environments.

  8. The unique resistance and resilience of the Nigerian West African Dwarf goat to gastrointestinal nematode infections

    Science.gov (United States)

    2011-01-01

    Background West African Dwarf (WAD) goats serve an important role in the rural village economy of West Africa, especially among small-holder livestock owners. They have been shown to be trypanotolerant and to resist infections with Haemonchus contortus more effectively than any other known breed of goat. Methods In this paper we review what is known about the origins of this goat breed, explain its economic importance in rural West Africa and review the current status of our knowledge about its ability to resist parasitic infections. Conclusions We suggest that its unique capacity to show both trypanotolerance and resistance to gastrointestinal (GI) nematode infections is immunologically based and genetically endowed, and that knowledge of the underlying genes could be exploited to improve the capacity of more productive wool and milk producing, but GI nematode susceptible, breeds of goats to resist infection, without recourse to anthelmintics. Either conventional breeding allowing introgression of resistance alleles into susceptible breeds, or transgenesis could be exploited for this purpose. Appropriate legal protection of the resistance alleles of WAD goats might provide a much needed source of revenue for the countries in West Africa where the WAD goats exist and where currently living standards among rural populations are among the lowest in the world. PMID:21291550

  9. Recombination suppression at the dominant Rhg1/Rfs2 locus underlying soybean resistance to the cyst nematode.

    Science.gov (United States)

    Afzal, Ahmed J; Srour, Ali; Saini, Navinder; Hemmati, Naghmeh; El Shemy, Hany A; Lightfoot, David A

    2012-04-01

    Host resistance to "yellow dwarf" or "moonlight" disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24-48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred.

  10. Divergent gene expression in the conserved dauer stage of the nematodes Pristionchus pacificus and Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Sinha Amit

    2012-06-01

    Full Text Available Abstract Background An organism can respond to changing environmental conditions by adjusting gene regulation and by forming alternative phenotypes. In nematodes, these mechanisms are coupled because many species will form dauer larvae, a stress-resistant and non-aging developmental stage, when exposed to unfavorable environmental conditions, and execute gene expression programs that have been selected for the survival of the animal in the wild. These dauer larvae represent an environmentally induced, homologous developmental stage across many nematode species, sharing conserved morphological and physiological properties. Hence it can be expected that some core components of the associated transcriptional program would be conserved across species, while others might diverge over the course of evolution. However, transcriptional and metabolic analysis of dauer development has been largely restricted to Caenorhabditis elegans. Here, we use a transcriptomic approach to compare the dauer stage in the evolutionary model system Pristionchus pacificus with the dauer stage in C. elegans. Results We have employed Agilent microarrays, which represent 20,446 P. pacificus and 20,143 C. elegans genes to show an unexpected divergence in the expression profiles of these two nematodes in dauer and dauer exit samples. P. pacificus and C. elegans differ in the dynamics and function of genes that are differentially expressed. We find that only a small number of orthologous gene pairs show similar expression pattern in the dauers of the two species, while the non-orthologous fraction of genes is a major contributor to the active transcriptome in dauers. Interestingly, many of the genes acquired by horizontal gene transfer and orphan genes in P. pacificus, are differentially expressed suggesting that these genes are of evolutionary and functional importance. Conclusion Our data set provides a catalog for future functional investigations and indicates novel insight

  11. Ectopic expression of AtPAD4 broadens resistance of soybean to soybean cyst and root-knot nematodes.

    Science.gov (United States)

    Youssef, Reham M; MacDonald, Margaret H; Brewer, Eric P; Bauchan, Gary R; Kim, Kyung-Hwan; Matthews, Benjamin F

    2013-04-25

    The gene encoding PAD4 (PHYTOALEXIN-DEFICIENT4) is required in Arabidopsis for expression of several genes involved in the defense response to Pseudomonas syringae pv. maculicola. AtPAD4 (Arabidopsis thaliana PAD4) encodes a lipase-like protein that plays a regulatory role mediating salicylic acid signaling. We expressed the gene encoding AtPAD4 in soybean roots of composite plants to test the ability of AtPAD4 to deter plant parasitic nematode development. The transformed roots were challenged with two different plant parasitic nematode genera represented by soybean cyst nematode (SCN; Heterodera glycines) and root-knot nematode (RKN; Meloidogyne incognita). Expression of AtPAD4 in soybean roots decreased the number of mature SCN females 35 days after inoculation by 68 percent. Similarly, soybean roots expressing AtPAD4 exhibited 77 percent fewer galls when challenged with RKN. Our experiments show that AtPAD4 can be used in an economically important crop, soybean, to provide a measure of resistance to two different genera of nematodes.

  12. Association analysis of resistance to cereal cyst nematodes (Heterodera avenae) and root lesion nematodes (Pratylenchus neglectus and P. thornei) in CIMMYT advanced spring wheat lines for semi-arid conditions.

    Science.gov (United States)

    Dababat, Abdelfattah A; Ferney, Gomez-Becerra Hugo; Erginbas-Orakci, Gul; Dreisigacker, Susanne; Imren, Mustafa; Toktay, Halil; Elekcioglu, Halil I; Mekete, Tesfamariam; Nicol, Julie M; Ansari, Omid; Ogbonnaya, Francis

    2016-12-01

    To identify loci linked to nematode resistance genes, a total of 126 of CIMMYT advanced spring wheat lines adapted to semi-arid conditions were screened for resistance to Heterodera avenae , Pratylenchus neglectus , and P. thornei , of which 107 lines were genotyped with 1,310 DArT. Association of DArT markers with nematode response was analyzed using the general linear model. Results showed that 11 markers were associated with resistance to H. avenae (pathotype Ha21), 25 markers with resistance to P. neglectus , and 9 significant markers were identified to be linked with resistance to P. thornei . In this work we confirmed that chromosome 4A (~90-105 cM) can be a source of resistance to P. thornei as has been recently reported. Other significant markers were also identified on chromosomal regions where no resistant genes have been reported for both nematodes species. These novel QTL were mapped to chromosomes 5A, 6A, and 7A for H. avenae ; on chromosomes 1A, 1B, 3A, 3B, 6B, 7AS, and 7D for P. neglectus ; and on chromosomes 1D, 2A, and 5B for P. thornei and represent potentially new loci linked to resistance that may be useful for selecting parents and deploying resistance into elite germplasm adapted to regions where nematodes are causing problem.

  13. Potential of Tissue Culture for Breeding Root-Knot Nematode Resistance into Vegetables

    OpenAIRE

    Fassuliotis, G.; Bhatt, D. P.

    1982-01-01

    Plant protoplast technology is being investigated as a means of transferring root-knot nematode resistance factors from Solanum sisymbriifolium into the susceptible S. melongena. Solanum sisymbriifolium plants regenerated from callus lost resistance to Meloidogyne javanica but retained resistance to M. incognita. Tomato plants cloned from leaf discs of the root-knot nematode resistant 'Patriot' were completely susceptible to M. incognita, while sections of stems and leaves rooted in sand in t...

  14. Sporamin-mediated resistance to beet cyst nematodes (Heterodera schachtii Schm.) is dependent on trypsin inhibitory activity in sugar beet (Beta vulgaris L.) hairy roots.

    Science.gov (United States)

    Cai, Daguang; Thurau, Tim; Tian, Yanyan; Lange, Tina; Yeh, Kai-Wun; Jung, Christian

    2003-04-01

    Sporamin, a sweet potato tuberous storage protein, is a Kunitz-type trypsin inhibitor. Its capability of conferring insect-resistance on transgenic tobacco and cauliflower has been confirmed. To test its potential as an anti-feedant for the beet cyst nematode (Heterodera schachtii Schm.), the sporamin gene SpTI-1 was introduced into sugar beet (Beta vulgaris L.) by Agrobacterium rhizogenes-mediated transformation. Twelve different hairy root clones expressing sporamin were selected for studying nematode development. Of these, 8 hairy root clones were found to show significant efficiency in inhibiting the growth and development of the female nematodes whereas 4 root clones did not show any inhibitory effects even though the SpTI-1 gene was regularly expressed in all of the tested hairy roots as revealed by northern and western analyses. Inhibition of nematode development correlated with trypsin inhibitor activity but not with the amount of sporamin expressed in hairy roots. These data demonstrate that the trypsin inhibitor activity is the critical factor for inhibiting growth and development of cyst nematodes in sugar beet hairy roots expressing the sporamin gene. Hence, the sweet potato sporamin can be used as a new and effective anti-feedant for controlling cyst nematodes offering an alternative strategy for establishing nematode resistance in crops.

  15. Characterization of the abomasal transcriptome for mechanisms of resistance to gastrointestinal nematodes in cattle

    Science.gov (United States)

    2011-01-01

    The response of the abomasal transcriptome to gastrointestinal parasites was evaluated in parasite-susceptible and parasite-resistant Angus cattle using RNA-seq at a depth of 23.7 million sequences per sample. These cattle displayed distinctly separate resistance phenotypes as assessed by fecal egg counts. Approximately 65.3% of the 23 632 bovine genes were expressed in the fundic abomasum. Of these, 13 758 genes were expressed in all samples tested and likely represent core components of the bovine abomasal transcriptome. The gene (BT14427) with the most abundant transcript, accounting for 10.4% of sequences in the transcriptome, is located on chromosome 29 and has unknown functions. Additionally, PIGR (1.6%), Complement C3 (0.7%), and Immunoglobulin J chain (0.5%) were among the most abundant transcripts in the transcriptome. Among the 203 genes impacted, 64 were significantly over-expressed in resistant animals at a stringent cutoff (FDR parasite resistance in cattle. Our results provide insights into the development of host immunity to gastrointestinal nematode infection and will facilitate understanding of mechanism underlying host resistance. PMID:22129081

  16. Analysis of Gene expression in soybean (Glycine max roots in response to the root knot nematode Meloidogyne incognita using microarrays and KEGG pathways

    Directory of Open Access Journals (Sweden)

    Gamal El-Din Abd El Kader Y

    2011-05-01

    Full Text Available Abstract Background Root-knot nematodes are sedentary endoparasites that can infect more than 3000 plant species. Root-knot nematodes cause an estimated $100 billion annual loss worldwide. For successful establishment of the root-knot nematode in its host plant, it causes dramatic morphological and physiological changes in plant cells. The expression of some plant genes is altered by the nematode as it establishes its feeding site. Results We examined the expression of soybean (Glycine max genes in galls formed in roots by the root-knot nematode, Meloidogyne incognita, 12 days and 10 weeks after infection to understand the effects of infection of roots by M. incognita. Gene expression was monitored using the Affymetrix Soybean GeneChip containing 37,500 G. max probe sets. Gene expression patterns were integrated with biochemical pathways from the Kyoto Encyclopedia of Genes and Genomes using PAICE software. Genes encoding enzymes involved in carbohydrate and cell wall metabolism, cell cycle control and plant defense were altered. Conclusions A number of different soybean genes were identified that were differentially expressed which provided insights into the interaction between M. incognita and soybean and into the formation and maintenance of giant cells. Some of these genes may be candidates for broadening plants resistance to root-knot nematode through over-expression or silencing and require further examination.

  17. Radiation-induced gene expression in the nematode caenorhabditis elegans

    International Nuclear Information System (INIS)

    Nelson, G.A.; Jones, T.A.; Chesnut, A.; Smith, A.L.

    2002-01-01

    We used the nematode C. elegans to characterize the genotoxic and cytotoxic effects of ionizing radiation in a simple animal model emphasizing the unique effects of charged particle radiation. Here we demonstrate by reverse transcription polymerase chain reaction (RT-PCR) differential display and whole genome microarray hybridization experiments that gamma rays, accelerated protons and iron ions at the same physical dose lead to unique transcription profiles. 599 of 17871 genes analyzed (3.4%) showed differential expression 3 hrs after exposure to 3 Gy of radiation. 193 were up-regulated, 406 were down-regulated and 90% were affected only by a single species of radiation. A novel statistical clustering technique identified the regulatory relationships between the radiation-modulated genes and showed that genes affected by each radiation species were associated with unique regulatory clusters. This suggests that independent homeostatic mechanisms are activated in response to radiation exposure as a function of track structure or ionization density. (author)

  18. Overexpression of four Arabidopsis thaliana NHLgenes in soybean (Glycine max) roots and their effect over resistance to the soybean cyst nematode (Heterodera glycines)

    Science.gov (United States)

    In the US, the soybean cyst nematode (SCN) is the most destructive pathogen of soybean. Currently grown soybean varieties are not resistant to all field populations of SCN. We genetically engineered soybean roots so they expressed genes from the model plant, Arabidopsis. When the Arabidopsis genes, ...

  19. Screening fusarium resistant rootstocks for plant parasitic nematode resistance

    Science.gov (United States)

    The phase out of methyl bromide has directed research toward alternative methods of managing soil-borne pathogens. A limiting factor in many watermelon producing regions is Fusarium wilt caused by the soil-borne fungi Fusarium oxysporum f.sp. niveum (FON). There is no varietal resistance to FON depl...

  20. The complete mitochondrial genomes of three parasitic nematodes of birds: a unique gene order and insights into nematode phylogeny

    Science.gov (United States)

    2013-01-01

    Background Analyses of mitochondrial (mt) genome sequences in recent years challenge the current working hypothesis of Nematoda phylogeny proposed from morphology, ecology and nuclear small subunit rRNA gene sequences, and raise the need to sequence additional mt genomes for a broad range of nematode lineages. Results We sequenced the complete mt genomes of three Ascaridia species (family Ascaridiidae) that infest chickens, pigeons and parrots, respectively. These three Ascaridia species have an identical arrangement of mt genes to each other but differ substantially from other nematodes. Phylogenetic analyses of the mt genome sequences of the Ascaridia species, together with 62 other nematode species, support the monophylies of seven high-level taxa of the phylum Nematoda: 1) the subclass Dorylaimia; 2) the orders Rhabditida, Trichinellida and Mermithida; 3) the suborder Rhabditina; and 4) the infraorders Spiruromorpha and Oxyuridomorpha. Analyses of mt genome sequences, however, reject the monophylies of the suborders Spirurina and Tylenchina, and the infraorders Rhabditomorpha, Panagrolaimomorpha and Tylenchomorpha. Monophyly of the infraorder Ascaridomorpha varies depending on the methods of phylogenetic analysis. The Ascaridomorpha was more closely related to the infraorders Rhabditomorpha and Diplogasteromorpha (suborder Rhabditina) than they were to the other two infraorders of the Spirurina: Oxyuridorpha and Spiruromorpha. The closer relationship among Ascaridomorpha, Rhabditomorpha and Diplogasteromorpha was also supported by a shared common pattern of mitochondrial gene arrangement. Conclusions Analyses of mitochondrial genome sequences and gene arrangement has provided novel insights into the phylogenetic relationships among several major lineages of nematodes. Many lineages of nematodes, however, are underrepresented or not represented in these analyses. Expanding taxon sampling is necessary for future phylogenetic studies of nematodes with mt genome

  1. identification of banana varieties with resistance to nematodes in ...

    African Journals Online (AJOL)

    jen

    Institut des Sciences Agronomiques du Rwanda (ISAR), ISAR-Kibungo, Ngoma district, Rwanda ... for sustainable nematode management. Previous studies ..... Technology Development and Transfer project. ... INIBAP, Montpellier, France.

  2. Mining predicted essential genes of Brugia malayi for nematode drug targets.

    Directory of Open Access Journals (Sweden)

    Sanjay Kumar

    Full Text Available We report results from the first genome-wide application of a rational drug target selection methodology to a metazoan pathogen genome, the completed draft sequence of Brugia malayi, a parasitic nematode responsible for human lymphatic filariasis. More than 1.5 billion people worldwide are at risk of contracting lymphatic filariasis and onchocerciasis, a related filarial disease. Drug treatments for filariasis have not changed significantly in over 20 years, and with the risk of resistance rising, there is an urgent need for the development of new anti-filarial drug therapies. The recent publication of the draft genomic sequence for B. malayi enables a genome-wide search for new drug targets. However, there is no functional genomics data in B. malayi to guide the selection of potential drug targets. To circumvent this problem, we have utilized the free-living model nematode Caenorhabditis elegans as a surrogate for B. malayi. Sequence comparisons between the two genomes allow us to map C. elegans orthologs to B. malayi genes. Using these orthology mappings and by incorporating the extensive genomic and functional genomic data, including genome-wide RNAi screens, that already exist for C. elegans, we identify potentially essential genes in B. malayi. Further incorporation of human host genome sequence data and a custom algorithm for prioritization enables us to collect and rank nearly 600 drug target candidates. Previously identified potential drug targets cluster near the top of our prioritized list, lending credibility to our methodology. Over-represented Gene Ontology terms, predicted InterPro domains, and RNAi phenotypes of C. elegans orthologs associated with the potential target pool are identified. By virtue of the selection procedure, the potential B. malayi drug targets highlight components of key processes in nematode biology such as central metabolism, molting and regulation of gene expression.

  3. Tomato progeny inherit resistance to the nematode Meloidogyne javanica linked to plant growth induced by the biocontrol fungus Trichoderma atroviride.

    Science.gov (United States)

    Medeiros, Hugo Agripino de; Araújo Filho, Jerônimo Vieira de; Freitas, Leandro Grassi de; Castillo, Pablo; Rubio, María Belén; Hermosa, Rosa; Monte, Enrique

    2017-01-10

    Root-knot nematodes (RKN) are major crop pathogens worldwide. Trichoderma genus fungi are recognized biocontrol agents and a direct activity of Trichoderma atroviride (Ta) against the RKN Meloidogyne javanica (Mj), in terms of 42% reduction of number of galls (NG), 60% of number of egg masses and 90% of number of adult nematodes inside the roots, has been observed in tomato grown under greenhouse conditions. An in vivo split-root designed experiment served to demonstrate that Ta induces systemic resistance towards Mj, without the need for the organisms to be in direct contact, and significantly reduces NG (20%) and adult nematodes inside tomato roots (87%). The first generation (F1) of Ta-primed tomato plants inherited resistance to RKN; although, the induction of defenses occurred through different mechanisms, and in varying degrees, depending on the Ta-Mj interaction. Plant growth promotion induced by Ta was inherited without compromising the level of resistance to Mj, as the progeny of Ta-primed plants displayed increased size and resistance to Mj without fitness costs. Gene expression results from the defense inductions in the offspring of Ta-primed plants, suggested that an auxin-induced reactive oxygen species production promoted by Ta may act as a major defense strategy during plant growth.

  4. A genome-wide association study of a global rice panel reveals resistance in Oryza sativa to root-knot nematodes.

    Science.gov (United States)

    Dimkpa, Stanley O N; Lahari, Zobaida; Shrestha, Roshi; Douglas, Alex; Gheysen, Godelieve; Price, Adam H

    2016-02-01

    The root-knot nematode Meloidogyne graminicola is one of the most serious nematode pests worldwide and represents a major constraint on rice production. While variation in the susceptibility of Asian rice (Oryza sativa) exists, so far no strong and reliable resistance has been reported. Quantitative trait loci for partial resistance have been reported but no underlying genes have been tagged or cloned. Here, 332 accessions of the Rice Diversity Panel 1 were assessed for gall formation, revealing large variation across all subpopulations of rice and higher susceptibility in temperate japonica accessions. Accessions Khao Pahk Maw and LD 24 appeared to be resistant, which was confirmed in large pot experiments where no galls were observed. Detailed observations on these two accessions revealed no nematodes inside the roots 2 days after inoculation and very few females after 17 days (5 in Khao Pahk Maw and 100 in the susceptible controls). These two cultivars appear ideal donors for breeding root-knot nematode resistance. A genome-wide association study revealed 11 quantitative trait loci, two of which are close to epistatic loci detected in the Bala x Azucena population. The discussion highlights a small number of candidate genes worth exploring further, in particular many genes with lectin domains and genes on chromosome 11 with homology to the Hordeum Mla locus. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  5. Enhanced resistance to soybean cyst nematode Heterodera glycines in transgenic soybean by silencing putative CLE receptors.

    Science.gov (United States)

    Guo, Xiaoli; Chronis, Demosthenis; De La Torre, Carola M; Smeda, John; Wang, Xiaohong; Mitchum, Melissa G

    2015-08-01

    CLE peptides are small extracellular proteins important in regulating plant meristematic activity through the CLE-receptor kinase-WOX signalling module. Stem cell pools in the SAM (shoot apical meristem), RAM (root apical meristem) and vascular cambium are controlled by CLE signalling pathways. Interestingly, plant-parasitic cyst nematodes secrete CLE-like effector proteins, which act as ligand mimics of plant CLE peptides and are required for successful parasitism. Recently, we demonstrated that Arabidopsis CLE receptors CLAVATA1 (CLV1), the CLAVATA2 (CLV2)/CORYNE (CRN) heterodimer receptor complex and RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2), which transmit the CLV3 signal in the SAM, are required for perception of beet cyst nematode Heterodera schachtii CLEs. Reduction in nematode infection was observed in clv1, clv2, crn, rpk2 and combined double and triple mutants. In an effort to develop nematode resistance in an agriculturally important crop, orthologues of Arabidopsis receptors including CLV1, CLV2, CRN and RPK2 were identified from soybean, a host for the soybean cyst nematode Heterodera glycines. For each of the receptors, there are at least two paralogues in the soybean genome. Localization studies showed that most receptors are expressed in the root, but vary in their level of expression and spatial expression patterns. Expression in nematode-induced feeding cells was also confirmed. In vitro direct binding of the soybean receptors with the HgCLE peptide was analysed. Knock-down of the receptors in soybean hairy roots showed enhanced resistance to SCN. Our findings suggest that targeted disruption of nematode CLE signalling may be a potential means to engineer nematode resistance in crop plants. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  6. [Recent findings on the genetics of gastro-intestinal nematode resistance in ruminants].

    Science.gov (United States)

    Carta, A; Scala, A

    2004-06-01

    , more attention is now being given to traits related to health (resistance to EST, mastitis or parasitic diseases). Some studies conducted in New Zealand and Australia showed that nematode resistance is genetically controlled with high heritabilities and quite low genetic correlations with production traits. In this sense, some studies showed that it is possible to decrease the number of parasites in the framework of a traditional breeding programme. However, in most situations, this trait is not extensively recorded due to the high cost of individual recording. Therefore, it would be useful to implement breeding strategies based on the knowledge of the genes involved in this trait expression. Traditionally, two approaches are available to locate a gene: i) genome scan; ii) candidate gene approach. The candidate gene approach attempts to link general resistance to some particular genes. To date, genetic resistance against parasites is considered to be linked with the MHC and IgE genes. Furthermore, several gene detection studies based on the genome scan approach for this trait are currently being carried out on both crossed experimental populations (fat x lean Blackface lines and Sarda x Lacaune) and pure breeds (Churra). The preliminary results seem promising as to the use of marker assisted or genotype assisted selection for this trait, which is difficult and expensive to measure on a population scale.

  7. Nuclear techniqes in the study of genetic resistance to gastrointestinal nematode infections of sheep

    International Nuclear Information System (INIS)

    Dargie, J.D.

    1984-01-01

    The paper reviews genetic resistance of sheep to gastrointestinal nematodes from the standpoint of resistance to the parasites themselves and of resistance to the diseases they produce. Attention is focused on infections with the abomasal parasite Haemonchus contortus and the small intestinal nematode Trichostrongylus colubriformis, and on the role of nuclear techniques both in verifying the existence of genetically based differences in resistance to these parasites and in gaining an understanding of the mechanisms involved. It is concluded that resistance to disease per se is much less important than resistance to parasite establishment and survival and that genetic studies could contribute substantially to the identification of the factors and variables responsible for the present inability to successfully vaccinate young animals against these infections. (author)

  8. Different responses of soybean cyst nematode resistance between two RIL populations derived from Peking x 7605 under two ecological sites.

    Science.gov (United States)

    Li, Yongchun; Guo, Na; Zhao, Jinming; Zhou, Bin; Xu, Ran; Ding, Hui; Zhao, Weiguo; Gai, Junyi; Xing, Han

    2016-12-01

    The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a plant-parasitic nematode that feeds on the roots of soybean and most economically devastating pathogen of soybean (Glycine max (L.) Merr.) worldwide. Host plant resistance is the most effective control method. To understand SCN resistance in different environments, two recombinant-inbred lines (RILs) populations NJ(RN)P7 (217 F 2:8:11 lines) and JN(RN)P7 (248 F 2:7:9 lines) were developed from the cross of the cultivars Peking x 7605 in Nanjing and Jinan, respectively, and examined in this study. Peking is resistant to SCN race 1 (HG types 2.5.7), while 7605 is highly susceptible. Chi-square test of frequency distribution of families' female index (FI) showed that resistance to SCN was significantly different between NJ(RN)P7 and JN(RN)P7 populations. Three recessive genes conditioned the inheritance of resistance to SCN race 1 in both populations, but significant difference was detected for the mean of FI on two populations (DM= -16.68, P< 0.01). This indicated that natural selection may affect resistance to SCN. By analysing the variation of phenotype, the genetic structure of the two populations was determined to be different. The inheritance and variation of resistance were confirmed by simple sequence repeat (SSR) markers. For the two populations, 10 SSR markers showed polymorphism of resistant and susceptible DNA bulks. Some markers associated with the resistance of SCN races 1, 2, 3 and 5, and two markers, Satt163 and Satt309, reportedly related to rgh1 were detected both in NJ(RN)P7 and JN(RN)P7 populations. The results support the view that a disease acts as a selective force on plant resistance characteristics, which may alter the relative fitness of resistance alleles.

  9. DNA marker-assisted evaluation of potato genotypes for potential resistance to potato cyst nematode pathotypes not yet invading into Japan.

    Science.gov (United States)

    Asano, Kenji; Kobayashi, Akira; Tsuda, Shogo; Nishinaka, Mio; Tamiya, Seiji

    2012-06-01

    One of major objectives of crop breeding is conferring resistance to diseases and pests. However, large-scale phenotypic evaluation for many diseases and pests is difficult because strict controls are required to prevent their spread. Detection of disease resistance genes by using DNA markers may be an alternative approach to select potentially resistant accessions. Potato (Solanum tuberosum L.) breeders in Japan extensively use resistance gene H1, which confers nearly absolute resistance to potato cyst nematode (Globodera rostochiensis) pathotype Ro1, the only pathotype found in Japan. However, considering the possibility of accidental introduction of the other pathotypes, breeding of resistant varieties is an important strategy to prevent infestation by non-invading pathotypes in Japan. In this study, to evaluate the prevalence of resistance genes in Japanese genetic resources, we developed a multiplex PCR method that simultaneously detects 3 resistance genes, H1, Gpa2 and Gro1-4. We revealed that many Japanese varieties possess not only H1 but Gpa2, which are potentially resistant to other pathotypes of potato cyst nematode. On the other hand, no genotype was found to have the Gro1-4, indicating importance of introduction of varieties having Gro1-4. Our results demonstrate the applicability of DNA-marker assisted evaluation of resistant potato genotypes without phenotypic evaluation.

  10. Evaluation of edible ginger and turmeric cultivars for root-knot nematode resistance

    Science.gov (United States)

    Edible ginger and turmeric roots are important agricultural commodities for the State of Hawaii. Bacterial wilt, Ralstonia solanacearum, and root-knot nematodes, Meloidogyne spp. are major factors hindering optimum production. An evaluation of tolerance and resistance to M. incognita was undertake...

  11. Effector gene birth in plant parasitic nematodes: Neofunctionalization of a housekeeping glutathione synthetase gene

    Science.gov (United States)

    Lilley, Catherine J.; Maqbool, Abbas; Wu, Duqing; Yusup, Hazijah B.; Jones, Laura M.; Birch, Paul R. J.; Urwin, Peter E.

    2018-01-01

    Plant pathogens and parasites are a major threat to global food security. Plant parasitism has arisen four times independently within the phylum Nematoda, resulting in at least one parasite of every major food crop in the world. Some species within the most economically important order (Tylenchida) secrete proteins termed effectors into their host during infection to re-programme host development and immunity. The precise detail of how nematodes evolve new effectors is not clear. Here we reconstruct the evolutionary history of a novel effector gene family. We show that during the evolution of plant parasitism in the Tylenchida, the housekeeping glutathione synthetase (GS) gene was extensively replicated. New GS paralogues acquired multiple dorsal gland promoter elements, altered spatial expression to the secretory dorsal gland, altered temporal expression to primarily parasitic stages, and gained a signal peptide for secretion. The gene products are delivered into the host plant cell during infection, giving rise to “GS-like effectors”. Remarkably, by solving the structure of GS-like effectors we show that during this process they have also diversified in biochemical activity, and likely represent the founding members of a novel class of GS-like enzyme. Our results demonstrate the re-purposing of an endogenous housekeeping gene to form a family of effectors with modified functions. We anticipate that our discovery will be a blueprint to understand the evolution of other plant-parasitic nematode effectors, and the foundation to uncover a novel enzymatic function. PMID:29641602

  12. A major QTL corresponding to the Rk locus for resistance to root-knot nematodes in cowpea (Vigna unguiculata L. Walp.).

    Science.gov (United States)

    Huynh, Bao-Lam; Matthews, William C; Ehlers, Jeffrey D; Lucas, Mitchell R; Santos, Jansen R P; Ndeve, Arsenio; Close, Timothy J; Roberts, Philip A

    2016-01-01

    Genome resolution of a major QTL associated with the Rk locus in cowpea for resistance to root-knot nematodes has significance for plant breeding programs and R gene characterization. Cowpea (Vigna unguiculata L. Walp.) is a susceptible host of root-knot nematodes (Meloidogyne spp.) (RKN), major plant-parasitic pests in global agriculture. To date, breeding for host resistance in cowpea has relied on phenotypic selection which requires time-consuming and expensive controlled infection assays. To facilitate marker-based selection, we aimed to identify and map quantitative trait loci (QTL) conferring the resistance trait. One recombinant inbred line (RIL) and two F2:3 populations, each derived from a cross between a susceptible and a resistant parent, were genotyped with genome-wide single nucleotide polymorphism (SNP) markers. The populations were screened in the field for root-galling symptoms and/or under growth-chamber conditions for nematode reproduction levels using M. incognita and M. javanica biotypes. One major QTL was mapped consistently on linkage group VuLG11 of each population. By genotyping additional cowpea lines and near-isogenic lines derived from conventional backcrossing, we confirmed that the detected QTL co-localized with the genome region associated with the Rk locus for RKN resistance that has been used in conventional breeding for many decades. This chromosomal location defined with flanking markers will be a valuable target in marker-assisted breeding and for positional cloning of genes controlling RKN resistance.

  13. Disruption of prefoldin-2 protein synthesis in root-knot nematodes via host-mediated gene silencing efficiently reduces nematode numbers and thus protects plants.

    Science.gov (United States)

    Ajjappala, Hemavathi; Chung, Ha Young; Sim, Joon-Soo; Choi, Inchan; Hahn, Bum-Soo

    2015-03-01

    The aim of this study is to demonstrate the feasibility of down-regulating endogeneous prefoldin-2 root-knot nematode transcripts by expressing dsRNA with sequence identity to the nematode gene in tobacco roots under the influence of strong Arabidopsis ubiquitin (UBQ1) promoter. Root-knot nematodes (RKNs) are sedentary endoparasites infecting a wide range of plant species. They parasitise the root system, thereby disrupting water and nutrient uptake and causing major reductions in crop yields. The most reliable means of controlling RKNs is via the use of soil fumigants such as methyl bromide. With the emergence of RNA interference (RNAi) technology, which permits host-mediated nematode gene silencing, a new strategy to control plant pathogens has become available. In the present study, we investigated host-induced RNAi gene silencing of prefoldin-2 in transgenic Nicotiana benthamiana. Reductions in prefoldin-2 mRNA transcript levels were observed when nematodes were soaked in a dsRNA solution in vitro. Furthermore, nematode reproduction was suppressed in RNAi transgenic lines, as evident by reductions in the numbers of root knots (by 34-60 % in independent RNAi lines) and egg masses (by 33-58 %). Endogenous expression of prefoldin-2, analysed via real-time polymerase chain reaction and Western blotting, revealed that the gene was strongly expressed in the pre-parasitic J2 stage. Our observations demonstrate the relevance and potential importance of targeting the prefoldin gene during the nematode life cycle. The work also suggests that further improvements in silencing efficiency in economically important crops can be accomplished using RNAi directed against plant-parasitic nematodes.

  14. Genetic analysis of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore cattle.

    Science.gov (United States)

    Passafaro, Tiago Luciano; Carrera, Juan Pablo Botero; dos Santos, Livia Loiola; Raidan, Fernanda Santos Silva; dos Santos, Dalinne Chrystian Carvalho; Cardoso, Eduardo Penteado; Leite, Romário Cerqueira; Toral, Fabio Luiz Buranelo

    2015-06-15

    The aim of the present study was to obtain genetic parameters for resistance to ticks, gastrointestinal nematodes (worms) and Eimeria spp. in Nellore cattle, analyze the inclusion of resistance traits in Nellore breeding programs and evaluate genetic selection as a complementary tool in parasite control programs. Counting of ticks, gastrointestinal nematode eggs and Eimeria spp. oocysts per gram of feces totaling 4270; 3872 and 3872 records from 1188; 1142 and 1142 animals, respectively, aged 146 to 597 days were used. The animals were classified as resistant (counts equal to zero) or susceptible (counts above zero) to each parasite. The statistical models included systematics effects of contemporary groups and the mean trajectory. The random effects included additive genetic effects, direct permanent environmental effects and residual. The mean trajectory and random effects were modeled with linear Legendre polynomials for all traits except for the mean trajectory of resistance to Eimeria spp., which employed the cubic polynomial. Heritability estimates were of low to moderate magnitude and ranged from 0.06 to 0.30, 0.06 to 0.33 and 0.04 to 0.33 for resistance to ticks, gastrointestinal nematodes and Eimeria spp., respectively. The posterior mean of genetic and environmental correlations for the same trait at different ages (205, 365, 450 and 550 days) were favorable at adjacent ages and unfavorable at distant ages. In general, the posterior mean of the genetic and environmental correlations between traits of resistance were low and high-density intervals were large and included zero in many cases. The heritability estimates support the inclusion of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore breeding programs. Genetic selection can increase the frequency of resistant animals and be used as a complementary tool in parasite control programs. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Characterisation of a collagen gene subfamily from the potato cyst nematode Globodera pallida.

    Science.gov (United States)

    Gray, L J; Curtis, R H; Jones, J T

    2001-01-24

    We have isolated two full-length genomic DNA sequences, which encode the cuticle collagen proteins GP-COL-1 and GP-COL-2, from the potato cyst nematode Globodera pallida. A third, partial collagen gene ORF termed gp-col-t(t=truncated) has also been isolated and appears to represent an unexpressed pseudogene. The gp-col-1 and gp-col-2 genes both contain three short (nematode growth and reproduction. Immunochemical studies indicate that the GP-COL-1 protein is specifically located in the hypodermis of G. pallida adult females.

  16. Using SNP markers to dissect linkage disequilibrium at a major quantitative trait locus for resistance to the potato cyst nematode Globodera pallida on potato chromosome V.

    Science.gov (United States)

    Achenbach, Ute; Paulo, Joao; Ilarionova, Evgenyia; Lübeck, Jens; Strahwald, Josef; Tacke, Eckhard; Hofferbert, Hans-Reinhard; Gebhardt, Christiane

    2009-02-01

    The damage caused by the parasitic root cyst nematode Globodera pallida is a major yield-limiting factor in potato cultivation . Breeding for resistance is facilitated by the PCR-based marker 'HC', which is diagnostic for an allele conferring high resistance against G. pallida pathotype Pa2/3 that has been introgressed from the wild potato species Solanum vernei into the Solanum tuberosum tetraploid breeding pool. The major quantitative trait locus (QTL) controlling this nematode resistance maps on potato chromosome V in a hot spot for resistance to various pathogens including nematodes and the oomycete Phytophthora infestans. An unstructured sample of 79 tetraploid, highly heterozygous varieties and breeding clones was selected based on presence (41 genotypes) or absence (38 genotypes) of the HC marker. Testing the clones for resistance to G. pallida confirmed the diagnostic power of the HC marker. The 79 individuals were genotyped for 100 single nucleotide polymorphisms (SNPs) at 10 loci distributed over 38 cM on chromosome V. Forty-five SNPs at six loci spanning 2 cM in the interval between markers GP21-GP179 were associated with resistance to G. pallida. Based on linkage disequilibrium (LD) between SNP markers, six LD groups comprising between 2 and 18 SNPs were identified. The LD groups indicated the existence of multiple alleles at a single resistance locus or at several, physically linked resistance loci. LD group C comprising 18 SNPs corresponded to the 'HC' marker. LD group E included 16 SNPs and showed an association peak, which positioned one nematode resistance locus physically close to the R1 gene family.

  17. Combined strategies to control antinematicidal -resistant gastrointestinal nematodes in small ruminants on organized farms in pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, K. K. [University of Agriculture, Faisalabad (Pakistan). Dept. of Parasitology

    2014-03-15

    Combined strategies to control antinematicidal -resistant gastrointestinal nematodes in small ruminants on organized farms in Pakistan Antinematicidal resistance has been rooted on all the continents particularly in areas where ovine and caprine are being reared intensively due to frequent annual use of broad-spectrum dewormers. Farmers rely on mono-strategic scheme by using synthetic drugs to treat their livestock which is deemed the easier way to control gastrointestinal nematode infections as compared to the other strategies. On the other hand, recurrent employment of antinematicidal chemotherapeutics has conduced to development and prevalence of resistance among nematode populations. In this regard, other advocating strategies such as grazing management, rotation of antinematicidal drugs (although it is too late), amelioration of animal immunity, genetic approaches, biological control, nutritional supplementation, avoidance of mass treatment, improvement of management, eradication of concurrent diseases, and phytotherapy should be considered too. Although, by far there are no commercialized substantial alternatives to chemotherapy, but the current substitutes could decrease the parasitic burden, which, in turn, restrict indiscriminate use of synthetic drugs. The resistance is more rampant on organized farms as compared to non organized farms in rural areas in Asian, African and South Latin American countries because tamed animal raisers in those areas depend on ethnobotanicals to treat parasitism due to high cost of allopathic drugs. Therefore, in this review, the different strategies to control the antinematicidal resistance on organized farms in Pakistan will be elaborated. (author)

  18. Combined strategies to control antinematicidal -resistant gastrointestinal nematodes in small ruminants on organized farms in pakistan

    International Nuclear Information System (INIS)

    Hamad, K.K.

    2014-01-01

    Combined strategies to control antinematicidal -resistant gastrointestinal nematodes in small ruminants on organized farms in Pakistan Antinematicidal resistance has been rooted on all the continents particularly in areas where ovine and caprine are being reared intensively due to frequent annual use of broad-spectrum dewormers. Farmers rely on mono-strategic scheme by using synthetic drugs to treat their livestock which is deemed the easier way to control gastrointestinal nematode infections as compared to the other strategies. On the other hand, recurrent employment of antinematicidal chemotherapeutics has conduced to development and prevalence of resistance among nematode populations. In this regard, other advocating strategies such as grazing management, rotation of antinematicidal drugs (although it is too late), amelioration of animal immunity, genetic approaches, biological control, nutritional supplementation, avoidance of mass treatment, improvement of management, eradication of concurrent diseases, and phytotherapy should be considered too. Although, by far there are no commercialized substantial alternatives to chemotherapy, but the current substitutes could decrease the parasitic burden, which, in turn, restrict indiscriminate use of synthetic drugs. The resistance is more rampant on organized farms as compared to non organized farms in rural areas in Asian, African and South Latin American countries because tamed animal raisers in those areas depend on ethnobotanicals to treat parasitism due to high cost of allopathic drugs. Therefore, in this review, the different strategies to control the antinematicidal resistance on organized farms in Pakistan will be elaborated. (author)

  19. Benzimidazole resistance of sheep nematodes in Norway confirmed through controlled efficacy test

    Directory of Open Access Journals (Sweden)

    Domke Atle V

    2012-08-01

    Full Text Available Abstract Background Resistance against benzimidazoles (BZ has recently been detected in Norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (FECRT. The use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (CET to get accurate information about resistant nematodes populations at species level. A CET was therefore performed with larvae from two flocks where BZ resistance was previously detected through FECRT. Results The latter test confirmed the previous results in both flocks. In flock A, the BZ resistant nematode population consisted solely of Haemonchus contortus, whereas H. contortus and Teladorsagia circumcincta comprised the resistant worm population in flock B. Conclusions Some discrepancies that have been recorded between FECRT and CET results regarding time for post-treatment coproscopical examination and a temporary suppression of faecal egg excretion are discussed.

  20. Anthelmintic resistance and multidrug resistance in sheep gastro-intestinal nematodes in France, Greece and Italy.

    Science.gov (United States)

    Geurden, Thomas; Hoste, Herve; Jacquiet, Philippe; Traversa, Donato; Sotiraki, Smaragda; Frangipane di Regalbono, Antonio; Tzanidakis, Nikolaos; Kostopoulou, Despoina; Gaillac, Christie; Privat, Simon; Giangaspero, Annunziata; Zanardello, Claudia; Noé, Laura; Vanimisetti, Bindu; Bartram, David

    2014-03-17

    Anthelmintic resistance (AR) in ovine gastro-intestinal nematodes has been reported to affect the health and productivity of sheep globally. The objective of the present study was to evaluate the efficacy of commonly used oral drenches in sheep in France, Greece and Italy. In each country, 10 farms were selected. On each farm, 50 animals were blocked based on the pre-treatment faecal egg count (FEC). Within each block, animals were randomly allocated to one of 5 treatment groups. In addition to an untreated control group, there were 4 groups treated per oral route: moxidectin (MOX) and ivermectin (IVM), both at 0.2mg/kg bodyweight, levamisole (LEV; at 7.5mg/kg bodyweight) and a benzimidazole (BZ; at 3.75-5mg/kg bodyweight). In France, animals were not treated with LEV, but with netobimin (NET; at 7.5mg/kg bodyweight). The FEC was monitored using a modified McMaster technique. Two weeks after treatment, individual faecal samples were taken from all animals and efficacy was calculated as the difference between arithmetic mean FEC of the control group versus each respective treatment group. The results of the present study indicate the high efficacy of treatment with oral formulations of MOX (99-100%) and IVM (98-100%) on all farms, except on 1 farm in Greece. On this farm, multi drug resistance (MDR) was identified involving 4 anthelmintics (efficacy MOX: 91%; IVM: 0%; BZ: 58% and LEV: 87%). In Greece and Italy, AR against LEV and BZ was observed on some farms, with MDR involving both anthelmintics on 3 farms in Greece and on 2 farms in Italy. In France, AR against BZ and NET was observed on all 10 farms included. In all countries, Teladorsagia sp. was the most common nematode larva identified after treatment, followed by Haemonchus sp. and Trichostrongylus sp., with differences among farms and treatments. The current study confirms the high efficacy of oral treatments with MOX and IVM, even on farms with worm populations resistant to BZ, LEV or NET. This study also

  1. Cloning and structural analysis of partial acetylcholine receptor subunit genes from the parasitic nematode Teladorsagia circumcincta

    NARCIS (Netherlands)

    Walker, J.; Hoekstra, R.; Roos, M. H.; Wiley, L. J.; Weiss, A. S.; Sangster, N. C.; Tait, A.

    2001-01-01

    Nematode nicotinic acetylcholine receptors (nAChRs) are the sites of action for the anthelmintic drug levamisole. Recent findings indicate that the molecular mechanism of levamisole resistance may involve changes in the number and/or functions of target nAChRs. Accordingly, we have used an RT-PCR

  2. Anthelmintic Resistance of Strongyle Nematodes to Ivermectin and Fenbendazole on Cart Horses in Gondar, Northwest Ethiopia

    OpenAIRE

    Seyoum, Zewdu; Zewdu, Alemu; Dagnachew, Shimelis; Bogale, Basazinew

    2017-01-01

    A study was conducted from November 2015 to April 2016 to determine fenbendazole and ivermectin resistance status of intestinal nematodes of cart horses in Gondar, Northwest Ethiopia. Forty-five strongyle infected animals were used for this study. The animals were randomly allocated into three groups (15 horses per group). Group I was treated with fenbendazole and Group II with ivermectin and Group III was left untreated. Faecal samples were collected from each cart horse before and after tre...

  3. Gastrointestinal nematodes and anthelmintic resistance in Danish goat herds

    DEFF Research Database (Denmark)

    Holm, Signe A.; Sørensen, Camilla; Thamsborg, Stig M.

    2014-01-01

    The prevalence of gastrointestinal parasites in Danish goats and the presence of anthelmintic resistance (AR) in 10 selected herds were investigated during April-September 2012. All Danish herds (n = 137) with 10 or more adult goats were invited to participate, and of these 27 herds met......, resistance to the most commonly used anthelmintics is widespread in larger goat herds throughout Denmark....

  4. Induced mutations in cucumber for resistance to nematodes (Meloidogyne spp.)

    International Nuclear Information System (INIS)

    Udalov, V.B.; Prikhod'ko, V.F.

    1989-01-01

    Full text: Seeds were treated with EI and selection was carried out over 5 years. In the susceptible cv. ''M15'' treated with 0.05% EI for 21 h 7.6% of plants were found resistant, 72% only slightly susceptible. Mutants were used in crosses and hybrids showed 57-89% resistance over 6 generations. (author)

  5. First Report of Anthelmintic Resistance in Gastrointestinal Nematodes of Sheep from Costa Rica

    Science.gov (United States)

    Maroto, R.; Jiménez, A. E.; Romero, J. J.; Alvarez, V.; De Oliveira, J. B.; Hernández, J.

    2011-01-01

    As the prevalence and severity of anthelmintic resistance continue to rise, nematode infections in sheep correspondingly reduce the profitability of the sheep industry. In Costa Rica, sheep production systems are increasing in both number and importance. A field trial study was carried out to detect the level of anthelmintic resistance to albendazole and ivermectin in gastrointestinal nematodes (GIN) of sheep from seven farms in Costa Rica. Resistance was determined using the fecal egg count reduction test (FECRT). Three treatment groups were assessed on each farm: control, albendazole, and ivermectin. Haemonchus spp. (71%), Strongyloides sp. (57%), and Trichostrongylus spp. (43%) presented resistance levels to albendazole, whereas Strongyloides sp. (43%), Haemonchus spp. (29%), and Trichostrongylus spp. (29%) were resistant to ivermectin. Haemonchus spp., Strongyloides sp., and Trichostrongylus spp. were the most resistant GIN to both products. This study suggests that frequency of treatment, exclusive chemical control, and visual estimation of animal weight to calculate dosage may contribute to the high levels of anthelmintic resistance that were observed on the farms analyzed herein. PMID:21772962

  6. Salicylic acid-induced glutathione status in tomato crop and resistance to root-knot nematode, Meloidogyne incognita (Kofoid & White Chitwood

    Directory of Open Access Journals (Sweden)

    Hari C. Meher

    2011-10-01

    Full Text Available Salicylic acid-(SA is a plant defense stimulator. Exogenous application of SA might influence the status of glutathione-(GSH. GSH activates and SA alters the expression of defense genes to modulate plant resistance against pathogens. The fate of GSH in a crop following SA treatment is largely unknown. The SA-induced profiles of free reduced-, free oxidized-(GSSG and protein bound-(PSSG glutathione in tomato crop following foliar treatment of transplant at 5.0-10.0 μg mL–1 were measured by liquid chromatography. Resistance to root-knot nematode, Meloidogyne incognita damaging tomato and crop performance were also evaluated. SA treatment at 5.0-10.0 μg mL–1 to tomato transplants increased GSH, GSSG and PSSG in plant leaf and root, more so in leaf, during crop growth and development. As the fruits ripened, GSH and PSSG increased and GSSG declined. SA reduced the root infection by M. incognita, nematode reproduction and thus, improved the resistance of tomato var. Pusa Ruby, but reduced crop growth and redox status. SA at 5.0 μg mL–1 improved yield and fruit quality. The study firstly linked SA with activation of glutathione metabolism and provided an additional dimension to the mechanism of induced resistance against obligate nematode pathogen. SA increased glutathione status in tomato crop, imparted resistance against M. incognita, augmented crop yield and functional food quality. SA can be applied at 5.0 μg mL–1 for metabolic engineering of tomato at transplanting to combine host-plant resistance and health benefits in formulating a strategic nematode management decision.

  7. Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species.

    Science.gov (United States)

    Ulloa, M; Wang, C; Saha, S; Hutmacher, R B; Stelly, D M; Jenkins, J N; Burke, J; Roberts, P A

    2016-04-01

    Chromosome substitution (CS) lines in plants are a powerful genetic resource for analyzing the contribution of chromosome segments to phenotypic variance. In this study, a series of interspecific cotton (Gossypium spp.) CS lines were used to identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode or fungal disease resistance traits. The CS lines were developed in the G. hirsutum L. TM-1 background with chromosome or chromosome segment substitutions from G. barbadense L. Pima 3-79 or G. tomentosum. Root-knot nematode (Meloidogyne incognita) and fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) (races 1 and 4) resistance alleles and quantitative trait loci (QTL) previously placed on cotton chromosomes using SSR markers in two interspecific recombinant inbred line populations were chosen for testing. Phenotypic responses of increased resistance or susceptibility in controlled inoculation and infested field assays confirmed the resistance QTLs, based on substitution with the positive or negative allele for resistance. Lines CS-B22Lo, CS-B04, and CS-B18 showed high resistance to nematode root-galling, confirming QTLs on chromosomes 4 and 22 (long arm) with resistance alleles from Pima 3-79. Line CS-B16 had less fusarium race 1-induced vascular root staining and higher percent survival than the TM-1 parent, confirming a major resistance QTL on chromosome 16. Lines CS-B(17-11) and CS-B17 had high fusarium race 4 vascular symptoms and low survival due to susceptible alleles introgressed from Pima 3-79, confirming the localization on chromosome 17 of an identified QTL with resistance alleles from TM1 and other resistant lines. Analyses validated regions on chromosomes 11, 16, and 17 harboring nematode and fusarium wilt resistance genes and demonstrated the value of CS lines as both a germplasm resource for breeding programs and as a powerful genetic analysis tool for determining QTL effects for disease

  8. Comparative efficacy of different anthelmintics against fenbendazole-resistant nematodes of pashmina goats.

    Science.gov (United States)

    Ram, H; Rasool, T J; Sharma, A K; Meena, H R; Singh, S K

    2007-08-01

    A trial using albendazole, albendazole plus rafoxanide combination, ivermectin and doramectin was conducted in Pashmina goats having history of fenbendazole resistance to Haemonchus spp. and maintained at high altitude (>2350 m above sea level). Day 0 infection level was variable in different groups of animals and their larval cultures indicated Haemonchus, Trichostrongylus, Ostertagia and Oesophagostomum spp. infection, in addition to Nematodirus spp. as observed in egg counts. Efficacy of drugs was calculated on day 14 post treatment by faecal egg count reduction test (FECRT). Albendazole was least effective (14%) followed by its combination with rafoxanide (54%). However, ivermectin and doramectin were 96% and 94% effective against gastrointestinal nematodes of Pashmina goats. It was concluded that use of albendazole and its combination with rafoxanide are ineffective in controlling the nematodes of goats at this farm; hence, future use must be avoided. However, regular monitoring of the efficacy of ivermectin and doramectin is needed.

  9. Anthelmintic resistant nematodes in goats in the Netherlands

    NARCIS (Netherlands)

    Borgsteede, F.H.M.; Pekelder, J.J.; Dercksen, D.P.

    1996-01-01

    A suspected case of anthelmintic resistance on a farm with Angora and Anglo-Nubian goats was confirmed in a controlled test. Twelve lambs of sheep were infected with larvae cultured from faeces of the goats. The lambs were allocated to four groups: untreated controls and lambs treated 21 days after

  10. Different responses of soybean cyst nematode resistance between ...

    Indian Academy of Sciences (India)

    2016-12-02

    Dec 2, 2016 ... 3Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan, Shandong 250100, People's Republic of ... SCN race 1 (HG types 2.5.7), while 7605 is highly susceptible. ... nomical and environmental friendly method to control ..... analysis and qualitative mapping of a major partial-resistance.

  11. Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

    Directory of Open Access Journals (Sweden)

    Lifeng Zhou

    2016-09-01

    Full Text Available Bursaphelenchus mucronatus (B. mucronatus isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus’ pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future.

  12. Concerted and nonconcerted evolution of the Hsp70 gene superfamily in two sibling species of nematodes.

    Science.gov (United States)

    Nikolaidis, Nikolas; Nei, Masatoshi

    2004-03-01

    We have identified the Hsp70 gene superfamily of the nematode Caenorhabditis briggsae and investigated the evolution of these genes in comparison with Hsp70 genes from C. elegans, Drosophila, and yeast. The Hsp70 genes are classified into three monophyletic groups according to their subcellular localization, namely, cytoplasm (CYT), endoplasmic reticulum (ER), and mitochondria (MT). The Hsp110 genes can be classified into the polyphyletic CYT group and the monophyletic ER group. The different Hsp70 and Hsp110 groups appeared to evolve following the model of divergent evolution. This model can also explain the evolution of the ER and MT genes. On the other hand, the CYT genes are divided into heat-inducible and constitutively expressed genes. The constitutively expressed genes have evolved more or less following the birth-and-death process, and the rates of gene birth and gene death are different between the two nematode species. By contrast, some heat-inducible genes show an intraspecies phylogenetic clustering. This suggests that they are subject to sequence homogenization resulting from gene conversion-like events. In addition, the heat-inducible genes show high levels of sequence conservation in both intra-species and inter-species comparisons, and in most cases, amino acid sequence similarity is higher than nucleotide sequence similarity. This indicates that purifying selection also plays an important role in maintaining high sequence similarity among paralogous Hsp70 genes. Therefore, we suggest that the CYT heat-inducible genes have been subjected to a combination of purifying selection, birth-and-death process, and gene conversion-like events.

  13. Gastrointestinal nematodes and anthelmintic resistance in Danish goat herds☆

    Science.gov (United States)

    Holm, Signe A.; Sörensen, Camilla R. L.; Thamsborg, Stig M.; Enemark, Heidi L.

    2014-01-01

    The prevalence of gastrointestinal parasites in Danish goats and the presence of anthelmintic resistance (AR) in 10 selected herds were investigated during April–September 2012. All Danish herds (n = 137) with 10 or more adult goats were invited to participate, and of these 27 herds met the inclusion criterion of more than 10 young kids never treated with anthelmintics. Questionnaire data on management were collected, and faecal samples from 252 kids were analysed by the McMaster technique. From all herds with a mean faecal egg count (FEC) above 300 eggs per g of faeces, pooled samples were stained with peanut agglutinin (PNA) for specific detection of Haemonchus contortus. Strongyle eggs were detected with an individual prevalence of 69%, including Nematodirus battus (3.6%) and other Nematodirus species (15.0%). Eimeria spp. were observed in 99.6% of the kids. H. contortus was found in 11 of 12 (92%) tested herds. Anthelmintics were used in 89% of the herds with mean treatment frequencies of 0.96 and 0.89 treatments per year for kids and adults, respectively. In 2011, new animals were introduced into 44% of the herds of which 25% practised quarantine anthelmintic treatments. In 10 herds the presence of AR was analysed by egg hatch assay and FEC reduction tests using ivermectin (0.3 mg/kg) or fenbendazole (10.0 mg/kg). AR against both fenbendazole and ivermectin was detected in seven herds; AR against fenbendazole in one herd, and AR against ivermectin in another herd. In conclusion, resistance to the most commonly used anthelmintics is widespread in larger goat herds throughout Denmark. PMID:25076056

  14. Gastrointestinal nematodes and anthelmintic resistance in Danish goat herds☆

    Directory of Open Access Journals (Sweden)

    Holm Signe A.

    2014-01-01

    Full Text Available The prevalence of gastrointestinal parasites in Danish goats and the presence of anthelmintic resistance (AR in 10 selected herds were investigated during April–September 2012. All Danish herds (n = 137 with 10 or more adult goats were invited to participate, and of these 27 herds met the inclusion criterion of more than 10 young kids never treated with anthelmintics. Questionnaire data on management were collected, and faecal samples from 252 kids were analysed by the McMaster technique. From all herds with a mean faecal egg count (FEC above 300 eggs per g of faeces, pooled samples were stained with peanut agglutinin (PNA for specific detection of Haemonchus contortus. Strongyle eggs were detected with an individual prevalence of 69%, including Nematodirus battus (3.6% and other Nematodirus species (15.0%. Eimeria spp. were observed in 99.6% of the kids. H. contortus was found in 11 of 12 (92% tested herds. Anthelmintics were used in 89% of the herds with mean treatment frequencies of 0.96 and 0.89 treatments per year for kids and adults, respectively. In 2011, new animals were introduced into 44% of the herds of which 25% practised quarantine anthelmintic treatments. In 10 herds the presence of AR was analysed by egg hatch assay and FEC reduction tests using ivermectin (0.3 mg/kg or fenbendazole (10.0 mg/kg. AR against both fenbendazole and ivermectin was detected in seven herds; AR against fenbendazole in one herd, and AR against ivermectin in another herd. In conclusion, resistance to the most commonly used anthelmintics is widespread in larger goat herds throughout Denmark.

  15. Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Fernanda Ramos

    2016-04-01

    Full Text Available Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70–100 calves or more of both genders with ≥200 eggs per gram of feces (EPG (sensitivity of 50 EPG. These calves were distributed into 10 groups (of 7–10 animals per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7–10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different

  16. Detection and characterization of Pasteuria 16S rRNA gene sequences from nematodes and soils.

    Science.gov (United States)

    Duan, Y P; Castro, H F; Hewlett, T E; White, J H; Ogram, A V

    2003-01-01

    Various bacterial species in the genus Pasteuria have great potential as biocontrol agents against plant-parasitic nematodes, although study of this important genus is hampered by the current inability to cultivate Pasteuria species outside their host. To aid in the study of this genus, an extensive 16S rRNA gene sequence phylogeny was constructed and this information was used to develop cultivation-independent methods for detection of Pasteuria in soils and nematodes. Thirty new clones of Pasteuria 16S rRNA genes were obtained directly from nematodes and soil samples. These were sequenced and used to construct an extensive phylogeny of this genus. These sequences were divided into two deeply branching clades within the low-G + C, Gram-positive division; some sequences appear to represent novel species within the genus Pasteuria. In addition, a surprising degree of 16S rRNA gene sequence diversity was observed within what had previously been designated a single strain of Pasteuria penetrans (P-20). PCR primers specific to Pasteuria 16S rRNA for detection of Pasteuria in soils were also designed and evaluated. Detection limits for soil DNA were 100-10,000 Pasteuria endospores (g soil)(-1).

  17. Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil.

    Science.gov (United States)

    Ramos, Fernanda; Portella, Luiza Pires; Rodrigues, Fernando de Souza; Reginato, Caroline Zamperete; Pötter, Luciana; Cezar, Alfredo Skrebsky; Sangioni, Luís Antônio; Vogel, Fernanda Silveira Flores

    2016-04-01

    Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70-100 calves or more of both genders with ≥ 200 eggs per gram of feces (EPG) (sensitivity of 50 EPG). These calves were distributed into 10 groups (of 7-10 animals) per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7-10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different chemical groups were effective

  18. Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil

    Science.gov (United States)

    Ramos, Fernanda; Portella, Luiza Pires; Rodrigues, Fernando de Souza; Reginato, Caroline Zamperete; Pötter, Luciana; Cezar, Alfredo Skrebsky; Sangioni, Luís Antônio; Vogel, Fernanda Silveira Flores

    2016-01-01

    Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70–100 calves or more of both genders with ≥200 eggs per gram of feces (EPG) (sensitivity of 50 EPG). These calves were distributed into 10 groups (of 7–10 animals) per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7–10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different chemical groups

  19. Phenalenone-type phytoalexins mediate resistance of banana plants (Musa spp.) to the burrowing nematode Radopholus similis.

    Science.gov (United States)

    Hölscher, Dirk; Dhakshinamoorthy, Suganthagunthalam; Alexandrov, Theodore; Becker, Michael; Bretschneider, Tom; Buerkert, Andreas; Crecelius, Anna C; De Waele, Dirk; Elsen, Annemie; Heckel, David G; Heklau, Heike; Hertweck, Christian; Kai, Marco; Knop, Katrin; Krafft, Christoph; Maddula, Ravi K; Matthäus, Christian; Popp, Jürgen; Schneider, Bernd; Schubert, Ulrich S; Sikora, Richard A; Svatoš, Aleš; Swennen, Rony L

    2014-01-07

    The global yield of bananas-one of the most important food crops-is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant-nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques (1)H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R. similis-caused lesions of the plants. The striking antinematode activity of the phenylphenalenone anigorufone, its ingestion by the nematode, and its subsequent localization in lipid droplets within the nematode is reported. The importance of varying local concentrations of these specialized metabolites in infected plant tissues, their involvement in the plant's defense system, and derived strategies for improving banana resistance are highlighted.

  20. Investigating trehalose synthesis genes after cold acclimation in the Antarctic nematode Panagrolaimus sp. DAW1

    Directory of Open Access Journals (Sweden)

    Anna C. Seybold

    2017-12-01

    Full Text Available Panagrolaimus sp. DAW1 is a freeze-tolerant Antarctic nematode which survives extensive intracellular ice formation. The molecular mechanisms of this extreme adaptation are still poorly understood. We recently showed that desiccation-enhanced RNA interference (RNAi soaking can be used in conjunction with quantitative polymerase chain reaction (qPCR to screen for phenotypes associated with reduced expression of candidate genes in Panagrolaimus sp. DAW1. Here, we present the use of this approach to investigate the role of trehalose synthesis genes in this remarkable organism. Previous studies have shown that acclimating Panagrolaimus sp. DAW1 at 5°C before freezing or desiccation substantially enhances survival. In this study, the expression of tps-2 and other genes associated with trehalose metabolism, as well as lea-1, hsp-70 and gpx-1, in cold-acclimated and non-acclimated nematodes was analyzed using qPCR. Pd-tps-2 and Pd-lea-1 were significantly upregulated after cold acclimation, indicating an inducible expression in the cold adaptation of Panagrolaimus sp. DAW1. The role of trehalose synthesis genes in Panagrolaimus sp. DAW1 was further investigated by RNAi. Compared to the controls, Pd-tps-2a(RNAi-treated and cold-acclimated nematodes showed a significant decrease in mRNA, but no change in trehalose content or freezing survival. The involvement of two other trehalose synthesis genes (tps-2b and gob-1 was also investigated. These findings provide the first functional genomic investigation of trehalose synthesis genes in the non-model organism Panagrolaimus sp. DAW1. The presence of several trehalose synthesis genes with different RNAi sensitivities suggests the existence of multiple backup systems in Panagrolaimus sp. DAW1, underlining the importance of this sugar in preparation for freezing.

  1. Root-Knot and Cyst Nematodes Activate Procambium-Associated Genes in Arabidopsis Roots

    Directory of Open Access Journals (Sweden)

    Yasuka L. Yamaguchi

    2017-07-01

    Full Text Available Developmental plasticity is one of the most striking features of plant morphogenesis, as plants are able to vary their shapes in response to environmental cues. Biotic or abiotic stimuli often promote organogenesis events in plants not observed under normal growth conditions. Root-knot nematodes (RKNs are known to parasitize multiple species of rooting plants and to induce characteristic tissue expansion called galls or root-knots on the roots of their hosts by perturbing the plant cellular machinery. Galls contain giant cells (GCs and neighboring cells, and the GCs are a source of nutrients for the parasitizing nematode. Highly active cell proliferation was observed in galls. However, the underlying mechanisms that regulate the symptoms triggered by the plant-nematode interaction have not yet been elucidated. In this study, we deciphered the molecular mechanism of gall formation with an in vitro infection assay system using RKN Meloidogyne incognita, and the model plant Arabidopsis thaliana. By taking advantages of this system, we performed next-generation sequencing-based transcriptome profiling, and found that the expression of procambium identity-associated genes were enriched during gall formation. Clustering analyses with artificial xylogenic systems, together with the results of expression analyses of the candidate genes, showed a significant correlation between the induction of gall cells and procambium-associated cells. Furthermore, the promoters of several procambial marker genes such as ATHB8, TDR and WOX4 were activated not only in M. incognita-induced galls, but similarly in M. javanica induced-galls and Heterodera schachtii-induced syncytia. Our findings suggest that phytoparasitic nematodes modulate the host’s developmental regulation of the vascular stem cells during gall formation.

  2. Root-Knot and Cyst Nematodes Activate Procambium-Associated Genes in Arabidopsis Roots.

    Science.gov (United States)

    Yamaguchi, Yasuka L; Suzuki, Reira; Cabrera, Javier; Nakagami, Satoru; Sagara, Tomomi; Ejima, Chika; Sano, Ryosuke; Aoki, Yuichi; Olmo, Rocio; Kurata, Tetsuya; Obayashi, Takeshi; Demura, Taku; Ishida, Takashi; Escobar, Carolina; Sawa, Shinichiro

    2017-01-01

    Developmental plasticity is one of the most striking features of plant morphogenesis, as plants are able to vary their shapes in response to environmental cues. Biotic or abiotic stimuli often promote organogenesis events in plants not observed under normal growth conditions. Root-knot nematodes (RKNs) are known to parasitize multiple species of rooting plants and to induce characteristic tissue expansion called galls or root-knots on the roots of their hosts by perturbing the plant cellular machinery. Galls contain giant cells (GCs) and neighboring cells, and the GCs are a source of nutrients for the parasitizing nematode. Highly active cell proliferation was observed in galls. However, the underlying mechanisms that regulate the symptoms triggered by the plant-nematode interaction have not yet been elucidated. In this study, we deciphered the molecular mechanism of gall formation with an in vitro infection assay system using RKN Meloidogyne incognita , and the model plant Arabidopsis thaliana. By taking advantages of this system, we performed next-generation sequencing-based transcriptome profiling, and found that the expression of procambium identity-associated genes were enriched during gall formation. Clustering analyses with artificial xylogenic systems, together with the results of expression analyses of the candidate genes, showed a significant correlation between the induction of gall cells and procambium-associated cells. Furthermore, the promoters of several procambial marker genes such as ATHB8 , TDR and WOX4 were activated not only in M. incognita -induced galls, but similarly in M. javanica induced-galls and Heterodera schachtii -induced syncytia. Our findings suggest that phytoparasitic nematodes modulate the host's developmental regulation of the vascular stem cells during gall formation.

  3. Identification and characterisation of a hyper-variable apoplastic effector gene family of the potato cyst nematodes.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Jones, John T; Urwin, Peter E

    2014-09-01

    Sedentary endoparasitic nematodes are obligate biotrophs that modify host root tissues, using a suite of effector proteins to create and maintain a feeding site that is their sole source of nutrition. Using assumptions about the characteristics of genes involved in plant-nematode biotrophic interactions to inform the identification strategy, we provide a description and characterisation of a novel group of hyper-variable extracellular effectors termed HYP, from the potato cyst nematode Globodera pallida. HYP effectors comprise a large gene family, with a modular structure, and have unparalleled diversity between individuals of the same population: no two nematodes tested had the same genetic complement of HYP effectors. Individuals vary in the number, size, and type of effector subfamilies. HYP effectors are expressed throughout the biotrophic stages in large secretory cells associated with the amphids of parasitic stage nematodes as confirmed by in situ hybridisation. The encoded proteins are secreted into the host roots where they are detectable by immunochemistry in the apoplasm, between the anterior end of the nematode and the feeding site. We have identified HYP effectors in three genera of plant parasitic nematodes capable of infecting a broad range of mono- and dicotyledon crop species. In planta RNAi targeted to all members of the effector family causes a reduction in successful parasitism.

  4. Identification and characterisation of a hyper-variable apoplastic effector gene family of the potato cyst nematodes.

    Directory of Open Access Journals (Sweden)

    Sebastian Eves-van den Akker

    2014-09-01

    Full Text Available Sedentary endoparasitic nematodes are obligate biotrophs that modify host root tissues, using a suite of effector proteins to create and maintain a feeding site that is their sole source of nutrition. Using assumptions about the characteristics of genes involved in plant-nematode biotrophic interactions to inform the identification strategy, we provide a description and characterisation of a novel group of hyper-variable extracellular effectors termed HYP, from the potato cyst nematode Globodera pallida. HYP effectors comprise a large gene family, with a modular structure, and have unparalleled diversity between individuals of the same population: no two nematodes tested had the same genetic complement of HYP effectors. Individuals vary in the number, size, and type of effector subfamilies. HYP effectors are expressed throughout the biotrophic stages in large secretory cells associated with the amphids of parasitic stage nematodes as confirmed by in situ hybridisation. The encoded proteins are secreted into the host roots where they are detectable by immunochemistry in the apoplasm, between the anterior end of the nematode and the feeding site. We have identified HYP effectors in three genera of plant parasitic nematodes capable of infecting a broad range of mono- and dicotyledon crop species. In planta RNAi targeted to all members of the effector family causes a reduction in successful parasitism.

  5. Anthelmintic-resistant nematodes in Irish commercial sheep flocks- the state of play

    Directory of Open Access Journals (Sweden)

    Good Barbara

    2012-12-01

    Full Text Available Abstract Anthelmintic resistance has been reported in most sheep producing countries. Prior to the mid 1990s, reports of anthelmintic resistance in Ireland were sparse and focused on benzimidazole, one of the three classes of anthelmintic available during this period. This evidence for efficacy issues on Irish farms combined with awareness that anthelmintic resistance was increasingly being reported in other countries prompted the need for more comprehensive investigations on Irish farms. Faecal egg count reduction and micro-agar larval development tests were employed to investigate resistance to benzimidazole, levamisole and macrocyclic lactone. There is compelling evidence for resistance to both benzimidazole (>88% of flocks and levamisole (>39% of flocks. Resistance of nematode populations to macrocyclic lactone was suspected on a small number of farms (11% but needs to be confirmed. The recent introduction of two new classes of anthelmintics, after over a 25 year interval, together with the evidence that anthelmintic resistance is reported within a relatively short time following the introduction of a new anthelmintic compound means that the challenge to the industry is immediate. Actions are urgently required to manage anthelmintic resistance so as to prolong the lifespan of anthelmintics.

  6. Genome-wide scan of gastrointestinal nematode resistance in closed Angus population selected for minimized influence of MHC.

    Science.gov (United States)

    Kim, Eui-Soo; Sonstegard, Tad S; da Silva, Marcos V G B; Gasbarre, Louis C; Van Tassell, Curtis P

    2015-01-01

    Genetic markers associated with parasite indicator traits are ideal targets for study of marker assisted selection aimed at controlling infections that reduce herd use of anthelminthics. For this study, we collected gastrointestinal (GI) nematode fecal egg count (FEC) data from post-weaning animals of an Angus resource population challenged to a 26 week natural exposure on pasture. In all, data from 487 animals was collected over a 16 year period between 1992 and 2007, most of which were selected for a specific DRB1 allele to reduce the influence of potential allelic variant effects of the MHC locus. A genome-wide association study (GWAS) based on BovineSNP50 genotypes revealed six genomic regions located on bovine Chromosomes 3, 5, 8, 15 and 27; which were significantly associated (-log10 p=4.3) with Box-Cox transformed mean FEC (BC-MFEC). DAVID analysis of the genes within the significant genomic regions suggested a correlation between our results and annotation for genes involved in inflammatory response to infection. Furthermore, ROH and selection signature analyses provided strong evidence that the genomic regions associated BC-MFEC have not been affected by local autozygosity or recent experimental selection. These findings provide useful information for parasite resistance prediction for young grazing cattle and suggest new candidate gene targets for development of disease-modifying therapies or future studies of host response to GI parasite infection.

  7. Genome-wide scan of gastrointestinal nematode resistance in closed Angus population selected for minimized influence of MHC.

    Directory of Open Access Journals (Sweden)

    Eui-Soo Kim

    Full Text Available Genetic markers associated with parasite indicator traits are ideal targets for study of marker assisted selection aimed at controlling infections that reduce herd use of anthelminthics. For this study, we collected gastrointestinal (GI nematode fecal egg count (FEC data from post-weaning animals of an Angus resource population challenged to a 26 week natural exposure on pasture. In all, data from 487 animals was collected over a 16 year period between 1992 and 2007, most of which were selected for a specific DRB1 allele to reduce the influence of potential allelic variant effects of the MHC locus. A genome-wide association study (GWAS based on BovineSNP50 genotypes revealed six genomic regions located on bovine Chromosomes 3, 5, 8, 15 and 27; which were significantly associated (-log10 p=4.3 with Box-Cox transformed mean FEC (BC-MFEC. DAVID analysis of the genes within the significant genomic regions suggested a correlation between our results and annotation for genes involved in inflammatory response to infection. Furthermore, ROH and selection signature analyses provided strong evidence that the genomic regions associated BC-MFEC have not been affected by local autozygosity or recent experimental selection. These findings provide useful information for parasite resistance prediction for young grazing cattle and suggest new candidate gene targets for development of disease-modifying therapies or future studies of host response to GI parasite infection.

  8. Resistance to Southern Root-knot Nematode (Meloidogyne incognita) in Wild Watermelon (Citrullus lanatus var. citroides).

    Science.gov (United States)

    Thies, Judy A; Ariss, Jennifer J; Kousik, Chandrasekar S; Hassell, Richard L; Levi, Amnon

    2016-03-01

    Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to possess varying degrees of resistance to RKN species. Experiments were conducted over 2 yr to assess resistance of southern RKN in C. lanatus var. citroides accessions from the U.S. Watermelon Plant Introduction Collection in an artificially infested field site at the U.S. Vegetable Laboratory in Charleston, SC. In the first study (2006), 19 accessions of C. lanatus var. citroides were compared with reference entries of Citrullus colocynthis and C. lanatus var. lanatus. Of the wild watermelon accessions, two entries exhibited significantly less galling than all other entries. Five of the best performing C. lanatus var. citroides accessions were evaluated with and without nematicide at the same field site in 2007. Citrullus lanatus var. citroides accessions performed better than C. lanatus var. lanatus and C. colocynthis. Overall, most entries of C. lanatus var. citroides performed similarly with and without nematicide treatment in regard to root galling, visible egg masses, vine vigor, and root mass. In both years of field evaluations, most C. lanatus var. citroides accessions showed lesser degrees of nematode reproduction and higher vigor and root mass than C. colocynthis and C. lanatus var. lanatus. The results of these two field evaluations suggest that wild watermelon populations may be useful sources of resistance to southern RKN.

  9. A high-resolution map of the H1 locus harbouring resistance to the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Bakker, Erin; Achenbach, Ute; Bakker, Jeroen; van Vliet, Joke; Peleman, Johan; Segers, Bart; van der Heijden, Stefan; van der Linde, Piet; Graveland, Robert; Hutten, Ronald; van Eck, Herman; Coppoolse, Eric; van der Vossen, Edwin; Bakker, Jaap; Goverse, Aska

    2004-06-01

    The resistance gene H1 confers resistance to the potato cyst nematode Globodera rostochiensis and is located at the distal end of the long arm of chromosome V of potato. For marker enrichment of the H1 locus, a bulked segregant analysis (BSA) was carried out using 704 AFLP primer combinations. A second source of markers tightly linked to H1 is the ultra-high-density (UHD) genetic map of the potato cross SH x RH. This map has been produced with 387 AFLP primer combinations and consists of 10,365 AFLP markers in 1,118 bins (http://www.dpw.wageningen-ur.nl/uhd/). Comparing these two methods revealed that BSA resulted in one marker/cM and the UHD map in four markers/cM in the H1 interval. Subsequently, a high-resolution genetic map of the H1 locus has been developed using a segregating F(1) SH x RH population consisting of 1,209 genotypes. Two PCR-based markers were designed at either side of the H1 gene to screen the 1,209 genotypes for recombination events. In the high-resolution genetic map, two of the four co-segregating AFLP markers could be separated from the H1 gene. Marker EM1 is located at a distance of 0.2 cM, and marker EM14 is located at a distance of 0.8 cM. The other two co-segregating markers CM1 (in coupling) and EM15 (in repulsion) could not be separated from the H1 gene.

  10. Evolution of GHF5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event.

    Science.gov (United States)

    Kyndt, Tina; Haegeman, Annelies; Gheysen, Godelieve

    2008-11-03

    Endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (GHF5) have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (PPN). The origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral GHF5 PPN endoglucanase. It is not clear whether this ancestral endoglucanase consisted of the whole gene cassette, containing a catalytic domain and a carbohydrate-binding module (CBM, type 2 in PPN and bacteria) or only of the catalytic domain while the CBM2 was retrieved by domain shuffling later in evolution. Previous studies on the evolution of these genes have focused primarily on data of sedentary nematodes, while in this study, extra data from migratory nematodes were included. Two new endoglucanases from the migratory nematodes Pratylenchus coffeae and Ditylenchus africanus were included in this study. The latter one is the first gene isolated from a PPN of a different superfamily (Sphaerularioidea); all previously known nematode endoglucanases belong to the superfamily Tylenchoidea (order Rhabditida). Phylogenetic analyses were conducted with the PPN GHF5 endoglucanases and homologous endoglucanases from bacterial and other eukaryotic lineages such as beetles, fungi and plants. No statistical incongruence between the phylogenetic trees deduced from the catalytic domain and the CBM2 was found, which could suggest that both domains have evolved together. Furthermore, based on gene structure data, we inferred a model for the evolution of the GHF5 endoglucanase gene structure in plant-parasitic nematodes. Our data confirm a close relationship between Pratylenchus spp. and the root knot nematodes, while some Radopholus similis endoglucanases are more similar to cyst nematode genes. We conclude that the ancestral PPN GHF5 endoglucanase gene most probably consisted of

  11. Evolution of GHF5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event

    Directory of Open Access Journals (Sweden)

    Gheysen Godelieve

    2008-11-01

    Full Text Available Abstract Background Endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (GHF5 have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (PPN. The origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral GHF5 PPN endoglucanase. It is not clear whether this ancestral endoglucanase consisted of the whole gene cassette, containing a catalytic domain and a carbohydrate-binding module (CBM, type 2 in PPN and bacteria or only of the catalytic domain while the CBM2 was retrieved by domain shuffling later in evolution. Previous studies on the evolution of these genes have focused primarily on data of sedentary nematodes, while in this study, extra data from migratory nematodes were included. Results Two new endoglucanases from the migratory nematodes Pratylenchus coffeae and Ditylenchus africanus were included in this study. The latter one is the first gene isolated from a PPN of a different superfamily (Sphaerularioidea; all previously known nematode endoglucanases belong to the superfamily Tylenchoidea (order Rhabditida. Phylogenetic analyses were conducted with the PPN GHF5 endoglucanases and homologous endoglucanases from bacterial and other eukaryotic lineages such as beetles, fungi and plants. No statistical incongruence between the phylogenetic trees deduced from the catalytic domain and the CBM2 was found, which could suggest that both domains have evolved together. Furthermore, based on gene structure data, we inferred a model for the evolution of the GHF5 endoglucanase gene structure in plant-parasitic nematodes. Our data confirm a close relationship between Pratylenchus spp. and the root knot nematodes, while some Radopholus similis endoglucanases are more similar to cyst nematode genes. Conclusion We conclude that the ancestral

  12. Isolating genes involved with genotoxic drug response in the nematode Caenorhabditis elegans using genome-wide RNAi screening

    DEFF Research Database (Denmark)

    Schøler, Lone Vedel; Møller, Tine Hørning; Nørgaard, Steffen

    2012-01-01

    The soil nematode Caenorhabditis elegans has become a popular genetic model organism used to study a broad range of complex biological processes, including development, aging, apoptosis, and DNA damage responses. Many genetic tools and tricks have been developed in C. elegans including knock down...... of gene expression via RNA interference (RNAi). In C. elegans RNAi can effectively be administrated via feeding the nematodes bacteria expressing double-stranded RNA targeting the gene of interest. Several commercial C. elegans RNAi libraries are available and hence gene inactivation using RNAi can...

  13. Lamoka, a variety with excellent chip color out of cold storage and resistance to the golden potato cyst nematode

    Science.gov (United States)

    Lamoka is a white-skinned, white-fleshed potato cultivar variety notable for excellent chip color from cold storage, good yield, and resistance to both common scab and race Ro1 of the golden potato cyst nematode (Globodera rostochiensis). It was selected from a cross made at Cornell University in 1...

  14. Between-breed variations in resistance/resilience to gastrointestinal nematodes among indigenous goat breeds in Uganda

    NARCIS (Netherlands)

    Onzima, R.B.; Mukiibi, Robert; Ampaire, A.; Benda-Beckmann, von K.; Kanis, E.

    2017-01-01

    Gastrointestinal nematodes (GINs), Haemonchus contortus, are a major health problem in goat production. Resistance to H. contortus, the most prevalent GIN in Uganda, was studied among three indigenous goat breeds to assess their differences. Twelve male goats of each breed approximately 7 months old

  15. Regulatory interplay between soybean root and soybean cyst nematode during a resistant and susceptible reaction

    Science.gov (United States)

    Background: Plant parasitic nematodes (PPNs) are obligate parasites that feed on the roots of living host plants. Often, these nematodes can lay hundreds of eggs, each capable of surviving in the soil for as long as 12 years. When it comes to wreaking havoc on agricultural yield, few nematodes can c...

  16. Host-Induced Silencing of Two Pharyngeal Gland Genes Conferred Transcriptional Alteration of Cell Wall-Modifying Enzymes of Meloidogyne incognita vis-à-vis Perturbed Nematode Infectivity in Eggplant.

    Science.gov (United States)

    Shivakumara, Tagginahalli N; Chaudhary, Sonam; Kamaraju, Divya; Dutta, Tushar K; Papolu, Pradeep K; Banakar, Prakash; Sreevathsa, Rohini; Singh, Bhupinder; Manjaiah, K M; Rao, Uma

    2017-01-01

    The complex parasitic strategy of Meloidogyne incognita appears to involve simultaneous expression of its pharyngeal gland-specific effector genes in order to colonize the host plants. Research reports related to effector crosstalk in phytonematodes for successful parasitism of the host tissue is yet underexplored. In view of this, we have used in planta effector screening approach to understand the possible interaction of pioneer genes ( msp-18 and msp-20 , putatively involved in late and early stage of M. incognita parasitism, respectively) with other unrelated effectors such as cell-wall modifying enzymes (CWMEs) in M. incognita . Host-induced gene silencing (HIGS) strategy was used to generate the transgenic eggplants expressing msp-18 and msp-20 , independently. Putative transformants were characterized via qRT-PCR and Southern hybridization assay. SiRNAs specific to msp-18 and msp - 20 were also detected in the transformants via Northern hybridization assay. Transgenic expression of the RNAi constructs of msp-18 and msp-20 genes resulted in 43.64-69.68% and 41.74-67.30% reduction in M. incognita multiplication encompassing 6 and 10 events, respectively. Additionally, transcriptional oscillation of CWMEs documented in the penetrating and developing nematodes suggested the possible interaction among CWMEs and pioneer genes. The rapid assimilation of plant-derived carbon by invading nematodes was also demonstrated using 14 C isotope probing approach. Our data suggests that HIGS of msp-18 and msp-20 , improves nematode resistance in eggplant by affecting the steady-state transcription level of CWME genes in invading nematodes, and safeguard the plant against nematode invasion at very early stage because nematodes may become the recipient of bioactive RNA species during the process of penetration into the plant root.

  17. Early responses of resistant and susceptible potato roots during invasion by the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Sheridan, Jacqueline P; Miller, Anthony J; Perry, Roland N

    2004-03-01

    Signals from roots of resistant (cv. Maris Piper) and susceptible (cv. Désirée) potato cultivars during invasion by second stage juveniles (J2s) of the potato cyst nematode, Globodera rostochiensis, were investigated. Novel experimental chambers enabled the recording of electrophysiological responses from roots during nematode invasion. The root cell membrane potentials were maintained throughout the 3 d required to assess invasion and feeding site development. The steady-state resting membrane potentials of Désirée were more negative than those of Maris Piper on day 1, but the reverse on day 3. After 5 d there was no difference between the two cultivars. Intracellular microelectrodes detected marked spike activity in roots after the application of J2s and there were distinct and reproducible differences between the two cultivars, with the response from Désirée being much greater than that from Maris Piper. The responses to mechanical stimulation of roots by blunt micropipettes and sharp electrodes were consistent and similar in both cultivars to the responses in Maris Piper obtained after nematode invasion, but could not account for the marked response found in Désirée. Exogenous application of exoenzymes, used to mimic nematode chemical secretions, resulted in a distinct depolarization pattern that, although similar in both cultivars, was different from patterns obtained during nematode invasion or mechanical stimulation. The pH of homogenates prepared from roots of both cultivars was measured and a Ca2+ channel blocker was used to assess the role of Ca2+ in nematode invasion. The results indicated a role for Ca2+ in the signalling events that occur during nematode invasion.

  18. A temporal assessment of nematode community structure and diversity in the rhizosphere of cisgenic Phytophthora infestans-resistant potatoes.

    Science.gov (United States)

    Ortiz, Vilma; Phelan, Sinead; Mullins, Ewen

    2016-12-01

    Nematodes play a key role in soil processes with alterations in the nematode community structure having the potential to considerably influence ecosystem functioning. As a result fluctuations in nematode diversity and/or community structure can be gauged as a 'barometer' of a soil's functional biodiversity. However, a deficit exists in regards to baseline knowledge and on the impact of specific GM crops on soil nematode populations and in particular in regard to the impact of GM potatoes on the diversity of nematode populations in the rhizosphere. The goal of this project was to begin to address this knowledge gap in regards to a GM potato line, cisgenically engineered for resistance to Phytophthora infestans (responsible organism of the Irish potato famine causing late blight disease). For this, a 3 year (2013, 2014, 2015) field experimental study was completed, containing two conventional genotypes (cvs. Desiree and Sarpo Mira) and a cisgenic genotype (cv. Desiree + Rpi-vnt1). Each potato genotype was treated with different disease management strategies (weekly chemical applications and corresponding no spray control). Hence affording the opportunity to investigate the temporal impact of potato genotype, disease management strategy (and their interaction) on the potato rhizosphere nematode community. Nematode structure and diversity were measured through established indices, accounts and taxonomy with factors recording a significant effect limited to the climatic conditions across the three seasons of the study and chemical applications associated with the selected disease management strategy. Based on the metrics studied, the cultivation of the cisgenic potato genotype exerted no significant effect (P > 0.05) on nematode community diversity or structure. The disease management treatments led to a reduction of specific trophic groups (e.g. Predacious c-p = 4), which of interest appeared to be counteracted by a potato genotype with vigorous growth phenotype

  19. Comparative genome analysis and resistance gene mapping in grain legumes

    International Nuclear Information System (INIS)

    Young, N.D.

    1998-01-01

    Using, DNA markers and genome organization, several important disease resistance genes have been analyzed in mungbean (Vigna radiata), cowpea (Vigna unguiculata), common bean (Phaseolus vulgaris), and soybean (Glycine max). In the process, medium-density linkage maps consisting of restriction fragment length polymorphism (RFLP) markers were constructed for both mungbean and cowpea. Comparisons between these maps, as well as the maps of soybean and common bean, indicate that there is significant conservation of DNA marker order, though the conserved blocks in soybean are much shorter than in the others. DNA mapping results also indicate that a gene for seed weight may be conserved between mungbean and cowpea. Using the linkage maps, genes that control bruchid (genus Callosobruchus) and powdery mildew (Erysiphe polygoni) resistance in mungbean, aphid resistance in cowpea (Aphis craccivora), and cyst nematode (Heterodera glycines) resistance in soybean have all been mapped and characterized. For some of these traits resistance was found to be oligogenic and DNA mapping uncovered multiple genes involved in the phenotype. (author)

  20. Oxfendazole Resistance in Gastrointestinal Nematodes of Beetal Goats at Livestock Farms of Punjab (Pakistan

    Directory of Open Access Journals (Sweden)

    M. Saeed

    2007-01-01

    Full Text Available This study was carried out to screen goat farms for anthelmintic resistance (AR against oxfendazole (OXF and to determine contributory factors for its development. For this purpose, Beetal goat farms (n = 18 were randomly selected, with natural mixed gastrointestinal nematodosis infection. In vivo (faecal egg count reduction test and in vitro (egg hatch assay tests were used to ascertain the presence of AR while a scorecard was used to determine the role of possible contributory factors for oxfendazole resistance. For in vivo test, the experimental animals were divided into two groups of 10 animals each; one group received OXF treatment, while the other served as control. Pre- and post-treatment coproculture was performed to identify the species and genera of nematodes. Egg hatch assay (EHA was used to confirm the results of FECRT. Fecal egg count reduction test (FECRT revealed the development of resistance on six farms and post-treatment larval cultures indicated Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, Teladorsagia circumcincta and Oesophagostomum spp. as dominant species with resistance. Furthermore, EHA confirmed the results of FECRT. Among the presumptive factors for AR, the highest composite score was for rotation of anthelmintics followed by treatment frequency, dose rate and nature of medication. The scorecard for the development of AR, used in this study, may be helpful for the assessment of contributory factors of AR.

  1. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes.

    Science.gov (United States)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S; Lozano-Torres, Jose L; Grundler, Florian M W; Siddique, Shahid

    2017-12-16

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in plant-nematode interactions remain unexplored. Here, we characterized the role of a group of cell wall receptor proteins in Arabidopsis, designated as polygalacturonase-inhibiting proteins (PGIPs), during infection with the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita. PGIPs are encoded by a family of two genes in Arabidopsis, and are involved in the formation of active OG elicitors. Our results show that PGIP gene expression is strongly induced in response to cyst nematode invasion of roots. Analyses of loss-of-function mutants and overexpression lines revealed that PGIP1 expression attenuates infection of host roots by cyst nematodes, but not root-knot nematodes. The PGIP1-mediated attenuation of cyst nematode infection involves the activation of plant camalexin and indole-glucosinolate pathways. These combined results provide new insights into the molecular mechanisms underlying plant damage perception and response pathways during infection by cyst and root-knot nematodes, and establishes the function of PGIP in plant resistance to cyst nematodes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Prevalence of drug-resistant gastrointestinal nematodes in an organized sheep farm

    Directory of Open Access Journals (Sweden)

    Ambalathaduvar Meenakshisundaram

    2014-12-01

    Full Text Available Aim: The present study was aimed to determine the resistance against albendazole, fenbendazole, levamisole and closantel in gastrointestinal (GI nematodes of sheep. Introduction: Anthelmintics are used traditionally as an integral part of helminthic control strategies for grazing livestock to prevent production losses from parasitic infections. The continuous and indiscriminate use of the same anthelmintics over years together as the sole means of control are now failing due to the emergence of resistance strains of helminths. Resistance to the commonly used anthelmintics in GI nematodes of sheep has become an increasingly widespread problem throughout the world. Materials and Methods: Fifty-five naturally infected Madras Red lambs of 6-12 months of age were selected and distributed randomly into five treatment groups of 11 animals each. Four groups were treated orally with albendazole (5 mg/kg, fenbendazole (7 mg/kg, levamisole (7.5 mg/kg and closantel (10 mg/kg respectively, whereas the fifth group served as untreated control. Fecal samples were collected per rectum of each lamb just prior to treatment (pre-treatment and on 7, 14, 21 and 28 days post-treatment. The anthelmintic resistance was evaluated by in vivo fecal egg count reduction test (FECRT, post-treatment larval culture and in vitro egg hatch assay. Results: In the FECRT, albendazole reduced the faecal egg count by 86.50%, 84.81%, 85.28% and 84.47% respectively for 4 weeks after treatment. Fecal egg count reduction using fenbendazole was 92.64, 93.04, 90.80 and 90.06% respectively for 4 weeks after treatment. The percent efficacy for levamisole and closantel was more than 95%. The post-treatment larval culture contained only Haemonchus contortus. In the in vitro egg hatch assay, the ED50 value for benzimidazole was 0.299 μg albendazole/ml and levamisole showed an ED50 value of 0.283 μg/ml. Conclusion: Our study confirmed the resistance of H. contortus to benzimidazole in sheep. .

  3. Mitochondrial genomes of Meloidogyne chitwoodi and M. incognita (Nematoda: Tylenchina): comparative analysis, gene order and phylogenetic relationships with other nematodes.

    Science.gov (United States)

    Humphreys-Pereira, Danny A; Elling, Axel A

    2014-01-01

    Root-knot nematodes (Meloidogyne spp.) are among the most important plant pathogens. In this study, the mitochondrial (mt) genomes of the root-knot nematodes, M. chitwoodi and M. incognita were sequenced. PCR analyses suggest that both mt genomes are circular, with an estimated size of 19.7 and 18.6-19.1kb, respectively. The mt genomes each contain a large non-coding region with tandem repeats and the control region. The mt gene arrangement of M. chitwoodi and M. incognita is unlike that of other nematodes. Sequence alignments of the two Meloidogyne mt genomes showed three translocations; two in transfer RNAs and one in cox2. Compared with other nematode mt genomes, the gene arrangement of M. chitwoodi and M. incognita was most similar to Pratylenchus vulnus. Phylogenetic analyses (Maximum Likelihood and Bayesian inference) were conducted using 78 complete mt genomes of diverse nematode species. Analyses based on nucleotides and amino acids of the 12 protein-coding mt genes showed strong support for the monophyly of class Chromadorea, but only amino acid-based analyses supported the monophyly of class Enoplea. The suborder Spirurina was not monophyletic in any of the phylogenetic analyses, contradicting the Clade III model, which groups Ascaridomorpha, Spiruromorpha and Oxyuridomorpha based on the small subunit ribosomal RNA gene. Importantly, comparisons of mt gene arrangement and tree-based methods placed Meloidogyne as sister taxa of Pratylenchus, a migratory plant endoparasitic nematode, and not with the sedentary endoparasitic Heterodera. Thus, comparative analyses of mt genomes suggest that sedentary endoparasitism in Meloidogyne and Heterodera is based on convergent evolution. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Anthelmintic Resistance of Strongyle Nematodes to Ivermectin and Fenbendazole on Cart Horses in Gondar, Northwest Ethiopia

    Directory of Open Access Journals (Sweden)

    Zewdu Seyoum

    2017-01-01

    Full Text Available A study was conducted from November 2015 to April 2016 to determine fenbendazole and ivermectin resistance status of intestinal nematodes of cart horses in Gondar, Northwest Ethiopia. Forty-five strongyle infected animals were used for this study. The animals were randomly allocated into three groups (15 horses per group. Group I was treated with fenbendazole and Group II with ivermectin and Group III was left untreated. Faecal samples were collected from each cart horse before and after treatment. Accordingly, the reduction in the mean fecal egg count at fourteen days of treatment for ivermectin and fenbendazole was 97.25% and 79.4%, respectively. It was significantly different in net egg count between treatment and control groups after treatment. From the study, resistance level was determined for fenbendazole and suspected for ivermectin. In addition, a questionnaire survey was also conducted on 90 selected cart owners to assess their perception on anthelmintics. In the survey, the most available drugs in the study area used by the owners were fenbendazole and ivermectin. Most respondents have no knowledge about drug management techniques. Hence, animal health extension services to create awareness regarding anthelmintic management that plays a key role in reducing the anthelmintic resistance parasites.

  5. Anthelmintic Resistance of Strongyle Nematodes to Ivermectin and Fenbendazole on Cart Horses in Gondar, Northwest Ethiopia.

    Science.gov (United States)

    Seyoum, Zewdu; Zewdu, Alemu; Dagnachew, Shimelis; Bogale, Basazinew

    2017-01-01

    A study was conducted from November 2015 to April 2016 to determine fenbendazole and ivermectin resistance status of intestinal nematodes of cart horses in Gondar, Northwest Ethiopia. Forty-five strongyle infected animals were used for this study. The animals were randomly allocated into three groups (15 horses per group). Group I was treated with fenbendazole and Group II with ivermectin and Group III was left untreated. Faecal samples were collected from each cart horse before and after treatment. Accordingly, the reduction in the mean fecal egg count at fourteen days of treatment for ivermectin and fenbendazole was 97.25% and 79.4%, respectively. It was significantly different in net egg count between treatment and control groups after treatment. From the study, resistance level was determined for fenbendazole and suspected for ivermectin. In addition, a questionnaire survey was also conducted on 90 selected cart owners to assess their perception on anthelmintics. In the survey, the most available drugs in the study area used by the owners were fenbendazole and ivermectin. Most respondents have no knowledge about drug management techniques. Hence, animal health extension services to create awareness regarding anthelmintic management that plays a key role in reducing the anthelmintic resistance parasites.

  6. First report of multiple anthelmintic resistance in nematodes of sheep in Colombia

    Directory of Open Access Journals (Sweden)

    Carlos M.B. Gárcia

    2016-03-01

    Full Text Available This study aimed to report the presence of parasites resistant to the most used anthelmintic drugs in sheep in Colombia. Four farms (denominated farm 1, 2, 3 and 4 were selected where the animals were not treated with anthelmintics for two months before the trial. Animals with faecal egg count (FEC above 150 and of different ages were allocated into six groups, each consisting of at least 5 animals. The drugs and dosages used were: ivermectin 1% (0.2 mg/kg, albendazole 25% (5 mg/kg, fenbendazole 10% (5 mg/kg, levamisole 10% (5 mg/kg, and moxidectin 1% (0.2 mg/kg. Anthelmintic efficacy was determined by the FEC reduction test (FECRT with a second sampling 14 days post-treatment. The efficacy of albendazole and fenbendazole at farm 1 was above 95%, which was different from the others farms. The FECRT indicated the presence of multidrug resistance in the other farms where no tested drugs showed activity higher than 79% (albendazole: 0 to 55%, fenbendazole: 51.4 to 76.6%, ivermectin: 67.3 to 93.1%, levamisole: 0 to 78.1%, and moxidectin: 49.2 to 64.1%.Haemonchus contortus was the predominant (96% species, followed by a small presence of Trichostrongylus sp. (3% andCooperia sp. (1%. Therefore, we report for the first time the existence of multiple anthelmintic resistance in gastrointestinal nematodes of sheep in Colombia.

  7. Microaspiration of esophageal gland cells and cDNA library construction for identifying parasitism genes of plant-parasitic nematodes.

    Science.gov (United States)

    Hussey, Richard S; Huang, Guozhong; Allen, Rex

    2011-01-01

    Identifying parasitism genes encoding proteins secreted from a plant-parasitic nematode's esophageal gland cells and injected through its stylet into plant tissue is the key to understanding the molecular basis of nematode parasitism of plants. Parasitism genes have been cloned by directly microaspirating the cytoplasm from the esophageal gland cells of different parasitic stages of cyst or root-knot nematodes to provide mRNA to create a gland cell-specific cDNA library by long-distance reverse-transcriptase polymerase chain reaction. cDNA clones are sequenced and deduced protein sequences with a signal peptide for secretion are identified for high-throughput in situ hybridization to confirm gland-specific expression.

  8. Discovery of genomic intervals that underlie nematode responses to benzimidazoles.

    Science.gov (United States)

    Zamanian, Mostafa; Cook, Daniel E; Zdraljevic, Stefan; Brady, Shannon C; Lee, Daehan; Lee, Junho; Andersen, Erik C

    2018-03-01

    Parasitic nematodes impose a debilitating health and economic burden across much of the world. Nematode resistance to anthelmintic drugs threatens parasite control efforts in both human and veterinary medicine. Despite this threat, the genetic landscape of potential resistance mechanisms to these critical drugs remains largely unexplored. Here, we exploit natural variation in the model nematodes Caenorhabditis elegans and Caenorhabditis briggsae to discover quantitative trait loci (QTL) that control sensitivity to benzimidazoles widely used in human and animal medicine. High-throughput phenotyping of albendazole, fenbendazole, mebendazole, and thiabendazole responses in panels of recombinant lines led to the discovery of over 15 QTL in C. elegans and four QTL in C. briggsae associated with divergent responses to these anthelmintics. Many of these QTL are conserved across benzimidazole derivatives, but others show drug and dose specificity. We used near-isogenic lines to recapitulate and narrow the C. elegans albendazole QTL of largest effect and identified candidate variants correlated with the resistance phenotype. These QTL do not overlap with known benzimidazole target resistance genes from parasitic nematodes and present specific new leads for the discovery of novel mechanisms of nematode benzimidazole resistance. Analyses of orthologous genes reveal conservation of candidate benzimidazole resistance genes in medically important parasitic nematodes. These data provide a basis for extending these approaches to other anthelmintic drug classes and a pathway towards validating new markers for anthelmintic resistance that can be deployed to improve parasite disease control.

  9. Evolutionary Expansion of WRKY Gene Family in Banana and Its Expression Profile during the Infection of Root Lesion Nematode, Pratylenchus coffeae

    Science.gov (United States)

    Suthanthiram, Backiyarani; Subbaraya, Uma; Marimuthu Somasundram, Saraswathi; Muthu, Mayilvaganan

    2016-01-01

    The WRKY family of transcription factors orchestrate the reprogrammed expression of the complex network of defense genes at various biotic and abiotic stresses. Within the last 96 million years, three rounds of Musa polyploidization events had occurred from selective pressure causing duplication of MusaWRKYs with new activities. Here, we identified a total of 153 WRKY transcription factors available from the DH Pahang genome. Based on their phylogenetic relationship, the MusaWRKYs available with complete gene sequence were classified into the seven common WRKY sub-groups. Synteny analyses data revealed paralogous relationships, with 17 MusaWRKY gene pairs originating from the duplication events that had occurred within the Musa lineage. We also found 15 other MusaWRKY gene pairs originating from much older duplication events that had occurred along Arecales and Poales lineage of commelinids. Based on the synonymous and nonsynonymous substitution rates, the fate of duplicated MusaWRKY genes was predicted to have undergone sub-functionalization in which the duplicated gene copies retain a subset of the ancestral gene function. Also, to understand the regulatory roles of MusaWRKY during a biotic stress, Illumina sequencing was performed on resistant and susceptible cultivars during the infection of root lesion nematode, Pratylenchus coffeae. The differential WRKY gene expression analysis in nematode resistant and susceptible cultivars during challenged and unchallenged conditions had distinguished: 1) MusaWRKYs participating in general banana defense mechanism against P.coffeae common to both susceptible and resistant cultivars, 2) MusaWRKYs that may aid in the pathogen survival as suppressors of plant triggered immunity, 3) MusaWRKYs that may aid in the host defense as activators of plant triggered immunity and 4) cultivar specific MusaWRKY regulation. Mainly, MusaWRKY52, -69 and -92 are found to be P.coffeae specific and can act as activators or repressors in a

  10. Evolutionary Expansion of WRKY Gene Family in Banana and Its Expression Profile during the Infection of Root Lesion Nematode, Pratylenchus coffeae.

    Directory of Open Access Journals (Sweden)

    Raja Kaliyappan

    Full Text Available The WRKY family of transcription factors orchestrate the reprogrammed expression of the complex network of defense genes at various biotic and abiotic stresses. Within the last 96 million years, three rounds of Musa polyploidization events had occurred from selective pressure causing duplication of MusaWRKYs with new activities. Here, we identified a total of 153 WRKY transcription factors available from the DH Pahang genome. Based on their phylogenetic relationship, the MusaWRKYs available with complete gene sequence were classified into the seven common WRKY sub-groups. Synteny analyses data revealed paralogous relationships, with 17 MusaWRKY gene pairs originating from the duplication events that had occurred within the Musa lineage. We also found 15 other MusaWRKY gene pairs originating from much older duplication events that had occurred along Arecales and Poales lineage of commelinids. Based on the synonymous and nonsynonymous substitution rates, the fate of duplicated MusaWRKY genes was predicted to have undergone sub-functionalization in which the duplicated gene copies retain a subset of the ancestral gene function. Also, to understand the regulatory roles of MusaWRKY during a biotic stress, Illumina sequencing was performed on resistant and susceptible cultivars during the infection of root lesion nematode, Pratylenchus coffeae. The differential WRKY gene expression analysis in nematode resistant and susceptible cultivars during challenged and unchallenged conditions had distinguished: 1 MusaWRKYs participating in general banana defense mechanism against P.coffeae common to both susceptible and resistant cultivars, 2 MusaWRKYs that may aid in the pathogen survival as suppressors of plant triggered immunity, 3 MusaWRKYs that may aid in the host defense as activators of plant triggered immunity and 4 cultivar specific MusaWRKY regulation. Mainly, MusaWRKY52, -69 and -92 are found to be P.coffeae specific and can act as activators or

  11. Comparative sequence analysis of the potato cyst nematode resistance locus H1 reveals a major lack of co-linearity between three haplotypes in potato (Solanum tuberosum ssp.).

    Science.gov (United States)

    Finkers-Tomczak, Anna; Bakker, Erin; de Boer, Jan; van der Vossen, Edwin; Achenbach, Ute; Golas, Tomasz; Suryaningrat, Suwardi; Smant, Geert; Bakker, Jaap; Goverse, Aska

    2011-02-01

    The H1 locus confers resistance to the potato cyst nematode Globodera rostochiensis pathotypes 1 and 4. It is positioned at the distal end of chromosome V of the diploid Solanum tuberosum genotype SH83-92-488 (SH) on an introgression segment derived from S. tuberosum ssp. andigena. Markers from a high-resolution genetic map of the H1 locus (Bakker et al. in Theor Appl Genet 109:146-152, 2004) were used to screen a BAC library to construct a physical map covering a 341-kb region of the resistant haplotype coming from SH. For comparison, physical maps were also generated of the two haplotypes from the diploid susceptible genotype RH89-039-16 (S. tuberosum ssp. tuberosum/S. phureja), spanning syntenic regions of 700 and 319 kb. Gene predictions on the genomic segments resulted in the identification of a large cluster consisting of variable numbers of the CC-NB-LRR type of R genes for each haplotype. Furthermore, the regions were interspersed with numerous transposable elements and genes coding for an extensin-like protein and an amino acid transporter. Comparative analysis revealed a major lack of gene order conservation in the sequences of the three closely related haplotypes. Our data provide insight in the evolutionary mechanisms shaping the H1 locus and will facilitate the map-based cloning of the H1 resistance gene.

  12. Obesity genes and insulin resistance.

    Science.gov (United States)

    Belkina, Anna C; Denis, Gerald V

    2010-10-01

    The exploding prevalence of insulin resistance and Type 2 diabetes (T2D) linked to obesity has become an alarming public health concern. Worldwide, approximately 171 million people suffer from obesity-induced diabetes and public health authorities expect this situation to deteriorate rapidly. An interesting clinical population of 'metabolically healthy but obese' (MHO) cases is relatively protected from T2D and its associated cardiovascular risk. The molecular basis for this protection is not well understood but is likely to involve reduced inflammatory responses. The inflammatory cells and pathways that respond to overnutrition are the primary subject matter for this review. The chance discovery of a genetic mutation in the Brd2 gene, which is located in the class II major histocompatibility complex and makes mice enormously fat but protects them from diabetes, offers revolutionary new insights into the cellular mechanisms that link obesity to insulin resistance and T2D. These Brd2-hypomorphic mice have reduced inflammation in fat that is normally associated with insulin resistance, and resemble MHO patients, suggesting novel therapeutic pathways for obese patients at risk for T2D. Deeper understanding of the functional links between genes that control inflammatory responses to diet-induced obesity is crucial to the development of therapies for obese, insulin-resistant patients.

  13. Evaluation of tomato genotypes for resistance to root-knot nematodes

    African Journals Online (AJOL)

    Tomato (Solanum lycopersicum) is one of the most popular vegetable crops worldwide, owing to its high nutritive value and diversified use. Tomato production in Ghana is threatened by plant parasitic nematodes, especially the root knot nematodes (Meloidogyne spp.), which are responsible for huge economic yield losses.

  14. Allyl isothiocyanate that induces GST and UGT expression confers oxidative stress resistance on C. elegans, as demonstrated by nematode biosensor.

    Directory of Open Access Journals (Sweden)

    Koichi Hasegawa

    Full Text Available BACKGROUND: Electrophilic xenobiotics and endogenous products from oxidative stresses induce the glutathione S-transferases (GSTs, which form a large family within the phase II enzymes over both animal and plant kingdoms. The GSTs thus induced in turn detoxify these external as well as internal stresses. Because these stresses are often linked to ageing and damage to health, the induction of phase II enzymes without causing adverse effects would be beneficial in slowing down ageing and keeping healthy conditions. METHODOLOGY/PRINCIPAL FINDINGS: We have tested this hypothesis by choosing allyl isothiocyanate (AITC, a functional ingredient in wasabi, as a candidate food ingredient that induces GSTs without causing adverse effects on animals' lives. To monitor the GST induction, we constructed a gst::gfp fusion gene and used it to transform Caenorhabditis elegans for use as a nematode biosensor. With the nematode biosensor, we found that AITC induced GST expression and conferred tolerance on the nematode against various oxidative stresses. We also present evidence that the transcription factor SKN-1 is involved in regulating the GST expression induced by AITC. CONCLUSIONS/SIGNIFICANCE: We show the applicability of the nematode biosensor for discovering and evaluating functional food substances and chemicals that would provide anti-ageing or healthful benefits.

  15. The complete mitochondrial genome of Setaria digitata (Nematoda: Filarioidea): Mitochondrial gene content, arrangement and composition compared with other nematodes.

    Science.gov (United States)

    Yatawara, Lalani; Wickramasinghe, Susiji; Rajapakse, R P V J; Agatsuma, Takeshi

    2010-09-01

    In the present study, we determined the complete mitochondrial (mt) genome sequence (13,839bp) of parasitic nematode Setaria digitata and its structure and organization compared with Onchocerca volvulus, Dirofilaria immitis and Brugia malayi. The mt genome of S. digitata is slightly larger than the mt genomes of other filarial nematodes. S. digitata mt genome contains 36 genes (12 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs) that are typically found in metazoans. This genome contains a high A+T (75.1%) content and low G+C content (24.9%). The mt gene order for S. digitata is the same as those for O. volvulus, D. immitis and B. malayi but it is distinctly different from other nematodes compared. The start codons inferred in the mt genome of S. digitata are TTT, ATT, TTG, ATG, GTT and ATA. Interestingly, the initiation codon TTT is unique to S. digitata mt genome and four protein-coding genes use this codon as a translation initiation codon. Five protein-coding genes use TAG as a stop codon whereas three genes use TAA and four genes use T as a termination codon. Out of 64 possible codons, only 57 are used for mitochondrial protein-coding genes of S. digitata. T-rich codons such as TTT (18.9%), GTT (7.9%), TTG (7.8%), TAT (7%), ATT (5.7%), TCT (4.8%) and TTA (4.1%) are used more frequently. This pattern of codon usage reflects the strong bias for T in the mt genome of S. digitata. In conclusion, the present investigation provides new molecular data for future studies of the comparative mitochondrial genomics and systematic of parasitic nematodes of socio-economic importance. 2010 Elsevier B.V. All rights reserved.

  16. Alternative splicing: a novel mechanism of regulation identified in the chorismate mutase gene of the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Lu, Shun-Wen; Tian, Duanhua; Borchardt-Wier, Harmony B; Wang, Xiaohong

    2008-11-01

    Chorismate mutase (CM) secreted from the stylet of plant-parasitic nematodes plays an important role in plant parasitism. We isolated and characterized a new nematode CM gene (Gr-cm-1) from the potato cyst nematode, Globodera rostochiensis. The Gr-cm-1 gene was found to exist in the nematode genome as a single-copy gene that has two different alleles, Gr-cm-1A and Gr-cm-1B, both of which could give rise to two different mRNA transcripts of Gr-cm-1 and Gr-cm-1-IRII. In situ mRNA hybridization showed that the Gr-cm-1 gene was exclusively expressed within the subventral oesophageal gland cells of the nematode. Gr-cm-1 was demonstrated to encode a functional CM (GR-CM-1) potentially having a dimeric structure as the secreted bacterial *AroQ CMs. Gr-cm-1-IRII, generated by retention of intron 2 of the Gr-cm-1 pre-mRNA through alternative splicing (AS), would encode a truncated protein (GR-CM-1t) lacking the CM domain with no CM activity. The quantitative real-time reverse transcription-PCR assay revealed that splicing of the Gr-cm-1 gene was developmentally regulated; Gr-cm-1 was up-regulated whereas Gr-cm-1-IRII was down-regulated in early nematode parasitic stages compared to the preparasitic juvenile stage. Low-temperature SDS-PAGE analysis revealed that GR-CM-1 could form homodimers when expressed in Escherichia coli and the dimerization domain was retained in the truncated GR-CM-1t protein. The specific interaction between the two proteins was demonstrated in yeast. Our data suggested that the novel splice variant might function as a dominant negative isoform through heterodimerization with the full-length GR-CM-1 protein and that AS may represent an important mechanism for regulating CM activity during nematode parasitism.

  17. Structural and functional diversity of CLAVATA3/ESR (CLE)-like genes from the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Lu, Shun-Wen; Chen, Shiyan; Wang, Jianying; Yu, Hang; Chronis, Demosthenis; Mitchum, Melissa G; Wang, Xiaohong

    2009-09-01

    Plant CLAVATA3/ESR-related (CLE) peptides have diverse roles in plant growth and development. Here, we report the isolation and functional characterization of five new CLE genes from the potato cyst nematode Globodera rostochiensis. Unlike typical plant CLE peptides that contain a single CLE motif, four of the five Gr-CLE genes encode CLE proteins with multiple CLE motifs. These Gr-CLE genes were found to be specifically expressed within the dorsal esophageal gland cell of nematode parasitic stages, suggesting a role for their encoded proteins in plant parasitism. Overexpression phenotypes of Gr-CLE genes in Arabidopsis mimicked those of plant CLE genes, and Gr-CLE proteins could rescue the Arabidopsis clv3-2 mutant phenotype when expressed within meristems. A short root phenotype was observed when synthetic GrCLE peptides were exogenously applied to roots of Arabidopsis or potato similar to the overexpression of Gr-CLE genes in Arabidopsis and potato hairy roots. These results reveal that G. rostochiensis CLE proteins with either single or multiple CLE motifs function similarly to plant CLE proteins and that CLE signaling components are conserved in both Arabidopsis and potato roots. Furthermore, our results provide evidence to suggest that the evolution of multiple CLE motifs may be an important mechanism for generating functional diversity in nematode CLE proteins to facilitate parasitism.

  18. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes.

    Science.gov (United States)

    Danchin, Etienne G J; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Guzeeva, Elena Sokolova; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T; den Akker, Sebastian Eves-van

    2017-10-23

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus , representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus , respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.

  19. Microevolution of Duplications and Deletions and Their Impact on Gene Expression in the Nematode Pristionchus pacificus.

    Directory of Open Access Journals (Sweden)

    Praveen Baskaran

    Full Text Available The evolution of diversity across the animal kingdom has been accompanied by tremendous gene loss and gain. While comparative genomics has been fruitful to characterize differences in gene content across highly diverged species, little is known about the microevolution of structural variations that cause these differences in the first place. In order to investigate the genomic impact of structural variations, we made use of genomic and transcriptomic data from the nematode Pristionchus pacificus, which has been established as a satellite model to Caenorhabditis elegans for comparative biology. We exploit the fact that P. pacificus is a highly diverse species for which various genomic data including the draft genome of a sister species P. exspectatus is available. Based on resequencing coverage data for two natural isolates we identified large (> 2 kb deletions and duplications relative to the reference strain. By restriction to completely syntenic regions between P. pacificus and P. exspectatus, we were able to polarize the comparison and to assess the impact of structural variations on expression levels. We found that while loss of genes correlates with lack of expression, duplication of genes has virtually no effect on gene expression. Further investigating expression of individual copies at sites that segregate between the duplicates, we found in the majority of cases only one of the copies to be expressed. Nevertheless, we still find that certain gene classes are strongly depleted in deletions as well as duplications, suggesting evolutionary constraint acting on synteny. In summary, our results are consistent with a model, where most structural variations are either deleterious or neutral and provide first insights into the microevolution of structural variations in the P. pacificus genome.

  20. Introgression of ivermectin resistance genes into a susceptible Haemonchus contortus strain by multiple backcrossing.

    Directory of Open Access Journals (Sweden)

    Elizabeth Redman

    2012-02-01

    Full Text Available Anthelmintic drug resistance in livestock parasites is already widespread and in recent years there has been an increasing level of anthelmintic drug selection pressure applied to parasitic nematode populations in humans leading to concerns regarding the emergence of resistance. However, most parasitic nematodes, particularly those of humans, are difficult experimental subjects making mechanistic studies of drug resistance extremely difficult. The small ruminant parasitic nematode Haemonchus contortus is a more amenable model system to study many aspects of parasite biology and investigate the basic mechanisms and genetics of anthelmintic drug resistance. Here we report the successful introgression of ivermectin resistance genes from two independent ivermectin resistant strains, MHco4(WRS and MHco10(CAVR, into the susceptible genome reference strain MHco3(ISE using a backcrossing approach. A panel of microsatellite markers were used to monitor the procedure. We demonstrated that after four rounds of backcrossing, worms that were phenotypically resistant to ivermectin had a similar genetic background to the susceptible reference strain based on the bulk genotyping with 18 microsatellite loci and individual genotyping with a sub-panel of 9 microsatellite loci. In addition, a single marker, Hcms8a20, showed evidence of genetic linkage to an ivermectin resistance-conferring locus providing a starting point for more detailed studies of this genomic region to identify the causal mutation(s. This work presents a novel genetic approach to study anthelmintic resistance and provides a "proof-of-concept" of the use of forward genetics in an important model strongylid parasite of relevance to human hookworms. The resulting strains provide valuable resources for candidate gene studies, whole genome approaches and for further genetic analysis to identify ivermectin resistance loci.

  1. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

    Full Text Available The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  2. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  3. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    NARCIS (Netherlands)

    Danchin, Etienne G.J.; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Rocha, Da Martine; Bajew, Simon; Neilson, Roy; Sokolova, Elena; Silva, Da Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Hans; Jones, John T.; Eves-van den Akker, Sebastian

    2017-01-01

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been

  4. Utilization of composite fecal samples for detection of anthelmintic resistance in gastrointestinal nematodes of cattle.

    Science.gov (United States)

    George, Melissa M; Paras, Kelsey L; Howell, Sue B; Kaplan, Ray M

    2017-06-15

    Recent reports indicate that anthelmintic resistance in gastrointestinal nematodes of cattle is becoming increasingly prevalent worldwide. Presently, the fecal egg count reduction test (FECRT) is the only means available for detection of resistance to anthelmintics in cattle herds at the farm level. However, the FECRT is labor and cost intensive, and consequently is only rarely performed on cattle farms unless for research purposes. If costs could be reduced, cattle producers might be more likely to pursue drug resistance testing on their farms. One approach to reducing the cost of the FECRT, is the use of composite fecal samples for performing fecal egg counts (FEC), rather than conducting FEC on fecal samples from 15 to 20 individual animals. In this study FECRT were performed on 14 groups of cattle using both individual and composite FEC methods To measure how well the results of composite sampling reproduce those of individual sampling, Lin's Concordance Correlation Coefficient was utilized to describe both the linear relationship between methods and the slope and y-intercept of the line relating the data sets. There was little difference between the approaches with 98% agreement in mean FEC found between methods Mean FEC based on individual counts ranged between 0 and 670.6 eggs per gram of feces, indicating that the results of this study are applicable to a wide range of FEC levels. Standard error of the mean FEC and range of FEC are reported for each group prior to and following treatment to describe the variability of the data set. There was greater than 95% agreement in drug efficacy between individual and composite sampling methods, demonstrating composite sampling is appropriate to evaluate drug efficacy. Notably, for all groups tested the efficacy calculated by composite sampling was within the 95% confidence interval for efficacy calculated using individual sampling. The use of composite samples was shown to reduce the number of FEC required by 79

  5. Identification of genes involved in the mutualistic colonization of the nematode Heterorhabditis bacteriophora by the bacterium Photorhabdus luminescens.

    LENUS (Irish Health Repository)

    Easom, Catherine A

    2010-01-01

    ABSTRACT: BACKGROUND: Photorhabdus are Gram negative entomopathogenic bacteria that also have a mutualistic association with nematodes from the family Heterorhabditis. An essential part of this symbiosis is the ability of the bacterium to colonize the gut of the freeliving form of the nematode called the infective juvenile (IJ). Although the colonization process (also called transmission) has been described phenomonologically very little is known about the underlying molecular mechanisms. Therefore, in this study, we were interested in identifying genes in Photorhabdus that are important for IJ colonization. RESULTS: In this work we genetically tagged P. luminescens TT01 with gfp and constructed a library containing over 3200 mutants using the suicide vector, pUT-Km2. Using a combination of in vitro symbiosis assays and fluorescent microscopy we screened this library for mutants that were affected in their ability to colonize the IJ i.e. with decreased transmission frequencies. In total 8 mutants were identified with transmission frequencies of <\\/= 30% compared to wild-type. These mutants were mapped to 6 different genetic loci; the pbgPE operon, galE, galU, proQ, asmA and hdfR. The pbgPE, galE and galU mutants were all predicted to be involved in LPS biosynthesis and, in support of this, we have shown that these mutants are avirulent and sensitive to the cationic antimicriobial peptide, polymyxin B. On the other hand the proQ, asmA and hdfR mutants were not affected in virulence and were either as resistant (proQ) or slightly more sensitive (asmA, hdfR) to polymyxin B than the wild-type (WT). CONCLUSIONS: This is the first report describing the outcome of a comprehensive screen looking for transmission mutants in Photorhabdus. In total 6 genetic loci were identified and we present evidence that all of these loci are involved in the assembly and\\/or maintenance of LPS and other factors associated with the cell surface. Interestingly several, but not all, of the

  6. Characterization of the abomasal transcriptome for mechanisms of resistance to gastrointestinal nematodes in cattle

    Directory of Open Access Journals (Sweden)

    Li Robert W

    2011-11-01

    Full Text Available Abstract The response of the abomasal transcriptome to gastrointestinal parasites was evaluated in parasite-susceptible and parasite-resistant Angus cattle using RNA-seq at a depth of 23.7 million sequences per sample. These cattle displayed distinctly separate resistance phenotypes as assessed by fecal egg counts. Approximately 65.3% of the 23 632 bovine genes were expressed in the fundic abomasum. Of these, 13 758 genes were expressed in all samples tested and likely represent core components of the bovine abomasal transcriptome. The gene (BT14427 with the most abundant transcript, accounting for 10.4% of sequences in the transcriptome, is located on chromosome 29 and has unknown functions. Additionally, PIGR (1.6%, Complement C3 (0.7%, and Immunoglobulin J chain (0.5% were among the most abundant transcripts in the transcriptome. Among the 203 genes impacted, 64 were significantly over-expressed in resistant animals at a stringent cutoff (FDR

  7. The Orphan Gene dauerless Regulates Dauer Development and Intraspecific Competition in Nematodes by Copy Number Variation.

    Directory of Open Access Journals (Sweden)

    Melanie G Mayer

    2015-06-01

    Full Text Available Many nematodes form dauer larvae when exposed to unfavorable conditions, representing an example of phenotypic plasticity and a major survival and dispersal strategy. In Caenorhabditis elegans, the regulation of dauer induction is a model for pheromone, insulin, and steroid-hormone signaling. Recent studies in Pristionchus pacificus revealed substantial natural variation in various aspects of dauer development, i.e. pheromone production and sensing and dauer longevity and fitness. One intriguing example is a strain from Ohio, having extremely long-lived dauers associated with very high fitness and often forming the most dauers in response to other strains' pheromones, including the reference strain from California. While such examples have been suggested to represent intraspecific competition among strains, the molecular mechanisms underlying these dauer-associated patterns are currently unknown. We generated recombinant-inbred-lines between the Californian and Ohioan strains and used quantitative-trait-loci analysis to investigate the molecular mechanism determining natural variation in dauer development. Surprisingly, we discovered that the orphan gene dauerless controls dauer formation by copy number variation. The Ohioan strain has one dauerless copy causing high dauer formation, whereas the Californian strain has two copies, resulting in strongly reduced dauer formation. Transgenic animals expressing multiple copies do not form dauers. dauerless is exclusively expressed in CAN neurons, and both CAN ablation and dauerless mutations increase dauer formation. Strikingly, dauerless underwent several duplications and acts in parallel or downstream of steroid-hormone signaling but upstream of the nuclear-hormone-receptor daf-12. We identified the novel or fast-evolving gene dauerless as inhibitor of dauer development. Our findings reveal the importance of gene duplications and copy number variations for orphan gene function and suggest daf-12 as

  8. GAMMA IRRADIATION OF SUGAR BEET SEEDS INDUCED PLANT RESISTANCE TO ROOT-KNOT NEMATODE MELOIDOGYNE INCOGNITA

    International Nuclear Information System (INIS)

    ABD EL FATTAH, A.I.; KAMEL, H.A.; EL-NAGDI, W.M.A.

    2008-01-01

    The main objective of this study was to investigate the effect of irradiation of sugar beet seeds on the plant resistance to root-knot nematode Meloidogyne incognita infection in addition to some morphological parameters, biochemical components and root technological characters. Relative to control (non-irradiated seeds), the obtained data showed that, all doses except 10 Gy significantly increased root length of un inoculated plants and the most effective dose was 200 Gy. All doses significantly decreased root diameter except 50 and 100 Gy. The 10 and 400 Gy significantly reduced root fresh weight while 50, 100 and 200 Gy caused non-significant increase. All doses significantly increased root fresh weight/dry weight than control. There was non-significant effect on the morphological parameters of the plants germinated from gamma irradiated seeds and inoculated with Meloidogyne incognita. Total chlorophyll of seed irradiated and un inoculated plants were significantly reduced by all doses except 200 Gy. All doses of gamma radiation caused non-significant decrease in the total chlorophyll of the infected plants. In un inoculated plants, a significant reduction in the total phenol was occurred due to all doses of gamma radiation. In contrast, in inoculated plants, 10 and 25 Gy caused significant reduction in the total phenol while 50 and 400 Gy caused significant increase in the total phenol.Significant increase in sucrose % was observed due to 10 Gy in the un inoculated plants. The 400 Gy caused significant decrease while other doses caused non-significant decrease in the sucrose %. In the inoculated plants, 50, 100 and 400 Gy caused significant increase in sucrose %. All doses significantly increased total soluble salts percent (TSS %) of either inoculated or un inoculated plants. Purity % was increased by all doses in the inoculated plants.The number of galls and egg masses were reduced gradually by increasing gamma doses and 100 Gy caused the highest reduction 89

  9. Anthelmintic resistance of nematodes in communally grazed goats in a semi-arid area of South Africa

    Directory of Open Access Journals (Sweden)

    F.R. Bakunzi

    2003-07-01

    Full Text Available A survey was conducted on the occurrence of anthelmintic resistance of nematodes in communally grazed goats in a semi-arid area in SouthAfrica. In herds belonging to 10 smallholder goat farmers, the efficacies of fenbendazole, levamisole and rafoxanide were tested by faecal egg count reduction (FECR tests. Efficacies of 80 % were considered a threshold for anthelmintic resistance. The FECR tests showed that all drugs tested more than 80 % effective in most instances, but there were notable exceptions. In 1 case, rafoxanide was only 31 % effective and in another case fenbendazole was only 47 % effective. The occurrence of anthelmintic resistance in this farming sector is of concern. Steps should be taken to prevent its further spread and to avoid the development of a situation as onnumerous commercial sheep farms in South Africa where resistance is very common.

  10. Identification and functional analysis of secreted effectors from phytoparasitic nematodes.

    Science.gov (United States)

    Rehman, Sajid; Gupta, Vijai K; Goyal, Aakash K

    2016-03-21

    Plant parasitic nematodes develop an intimate and long-term feeding relationship with their host plants. They induce a multi-nucleate feeding site close to the vascular bundle in the roots of their host plant and remain sessile for the rest of their life. Nematode secretions, produced in the oesophageal glands and secreted through a hollow stylet into the host plant cytoplasm, are believed to play key role in pathogenesis. To combat these persistent pathogens, the identity and functional analysis of secreted effectors can serve as a key to devise durable control measures. In this review, we will recapitulate the knowledge over the identification and functional characterization of secreted nematode effector repertoire from phytoparasitic nematodes. Despite considerable efforts, the identity of genes encoding nematode secreted proteins has long been severely hampered because of their microscopic size, long generation time and obligate biotrophic nature. The methodologies such as bioinformatics, protein structure modeling, in situ hybridization microscopy, and protein-protein interaction have been used to identify and to attribute functions to the effectors. In addition, RNA interference (RNAi) has been instrumental to decipher the role of the genes encoding secreted effectors necessary for parasitism and genes attributed to normal development. Recent comparative and functional genomic approaches have accelerated the identification of effectors from phytoparasitic nematodes and offers opportunities to control these pathogens. Plant parasitic nematodes pose a serious threat to global food security of various economically important crops. There is a wealth of genomic and transcriptomic information available on plant parasitic nematodes and comparative genomics has identified many effectors. Bioengineering crops with dsRNA of phytonematode genes can disrupt the life cycle of parasitic nematodes and therefore holds great promise to develop resistant crops against plant

  11. The AAP gene family for amino acid permeases contributes to development of the cyst nematode Heterodera schachtii in roots of Arabidopsis.

    Science.gov (United States)

    Elashry, Abdelnaser; Okumoto, Sakiko; Siddique, Shahid; Koch, Wolfgang; Kreil, David P; Bohlmann, Holger

    2013-09-01

    The beet cyst nematode Heterodera schachtii is able to infect Arabidopsis plants and induce feeding sites in the root. These syncytia are the only source of nutrients for the nematodes throughout their life and are a nutrient sink for the host plant. We have studied here the role of amino acid transporters for nematode development. Arabidopsis contains a large number of different amino acid transporters in several gene families but those of the AAP family were found to be especially expressed in syncytia. Arabidopsis contains 8 AAP genes and they were all strongly expressed in syncytia with the exception of AAP5 and AAP7, which were slightly downregulated. We used promoter::GUS lines and in situ RT-PCR to confirm the expression of several AAP genes and LHT1, a lysine- and histidine-specific amino acid transporter, in syncytia. The strong expression of AAP genes in syncytia indicated that these transporters are important for the transport of amino acids into syncytia and we used T-DNA mutants for several AAP genes to test for their influence on nematode development. We found that mutants of AAP1, AAP2, and AAP8 significantly reduced the number of female nematodes developing on these plants. Our study showed that amino acid transport into syncytia is important for the development of the nematodes. Copyright © 2013 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  12. Introduction of beet cyst nematode resistance from Sinapis alba L. and Raphanus sativus L. into Brassica napus L. (oil-seed rape) through sexual and somatic hybridization

    NARCIS (Netherlands)

    Lelivelt, C.L.C.

    1993-01-01

    Experiments were performed to select for beet cyst nematode (Heterodera schachtii Schm., abbrev. BCN) resistant genotypes of Brassica napus L. (oilseed rape), and to introduce BCN-resistance from the related species Raphanus

  13. Using SNP markers to dissect linkage disequilibrium at a major quantitative trait locus for resistance to the potato cyst nematode Globodera pallida on potato chromosome V

    NARCIS (Netherlands)

    Achenbach, U.; Caldas Paulo, M.J.; Ilarionova, E.; Lübeck, J.; Strahwald, J.; Tacke, E.; Hofferbert, H.R.

    2009-01-01

    The damage caused by the parasitic root cyst nematode Globodera pallida is a major yield-limiting factor in potato cultivation . Breeding for resistance is facilitated by the PCR-based marker 'HC', which is diagnostic for an allele conferring high resistance against G. pallida pathotype Pa2/3 that

  14. Identification of novel target genes for safer and more specific control of root-knot nematodes from a pan-genome mining.

    Directory of Open Access Journals (Sweden)

    Etienne G J Danchin

    2013-10-01

    Full Text Available Root-knot nematodes are globally the most aggressive and damaging plant-parasitic nematodes. Chemical nematicides have so far constituted the most efficient control measures against these agricultural pests. Because of their toxicity for the environment and danger for human health, these nematicides have now been banned from use. Consequently, new and more specific control means, safe for the environment and human health, are urgently needed to avoid worldwide proliferation of these devastating plant-parasites. Mining the genomes of root-knot nematodes through an evolutionary and comparative genomics approach, we identified and analyzed 15,952 nematode genes conserved in genomes of plant-damaging species but absent from non target genomes of chordates, plants, annelids, insect pollinators and mollusks. Functional annotation of the corresponding proteins revealed a relative abundance of putative transcription factors in this parasite-specific set compared to whole proteomes of root-knot nematodes. This may point to important and specific regulators of genes involved in parasitism. Because these nematodes are known to secrete effector proteins in planta, essential for parasitism, we searched and identified 993 such effector-like proteins absent from non-target species. Aiming at identifying novel targets for the development of future control methods, we biologically tested the effect of inactivation of the corresponding genes through RNA interference. A total of 15 novel effector-like proteins and one putative transcription factor compatible with the design of siRNAs were present as non-redundant genes and had transcriptional support in the model root-knot nematode Meloidogyne incognita. Infestation assays with siRNA-treated M. incognita on tomato plants showed significant and reproducible reduction of the infestation for 12 of the 16 tested genes compared to control nematodes. These 12 novel genes, showing efficient reduction of parasitism when

  15. Transcription of Biotic Stress Associated Genes in White Clover (Trifolium repens L.) Differs in Response to Cyst and Root-Knot Nematode Infection.

    Science.gov (United States)

    Islam, Afsana; Mercer, Chris F; Leung, Susanna; Dijkwel, Paul P; McManus, Michael T

    2015-01-01

    The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species.

  16. Multiyear evaluation of the durability of the resistance conferred by Ma and RMia genes to Meloidogyne incognita in Prunus under controlled conditions.

    Science.gov (United States)

    Khallouk, Samira; Voisin, Roger; Portier, Ulysse; Polidori, Joël; Van Ghelder, Cyril; Esmenjaud, Daniel

    2013-08-01

    Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession 'P.2175', which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × ['Garfi' almond × 'Nemared' peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to

  17. Poor efficacy of the most commonly used anthelmintics in sport horse nematodes in Morocco in relation to resistance

    Directory of Open Access Journals (Sweden)

    Zouiten H.

    2005-12-01

    Full Text Available Sport and leisure horses in Morocco are treated with several anthelmintics, organophosphates (dichlorvos, benzimidazoles (mostly thiabendazole or tetrahydropyrimidines (mostly pyrantel pamoate against nematodes. We studied three horse stables in Rabat, one in Meknes and one in Bouznika. Two of the Rabat and Bouznika stables had introduced a large number of horses from countries (Argentina or Europe where resistance to benzimidazoles is frequent, whereas the Meknes stud farm remained without foreign introduction. The number of treatments was not very frequent (twice a year in adult horses but the same anthelmintics were used repeatedly. No resistance to dichlorvos was detected whereas benzimidazole and pyrantel pamoate resistances were detected for the first time in African horses, outside South Africa.

  18. Identification and characterization of parasitism genes from the pinewood nematode Bursaphelenchus xylophilus reveals a multilayered detoxification strategy.

    Science.gov (United States)

    Espada, Margarida; Silva, Ana Cláudia; Eves van den Akker, Sebastian; Cock, Peter J A; Mota, Manuel; Jones, John T

    2016-02-01

    The migratory endoparasitic nematode Bursaphelenchus xylophilus, which is the causal agent of pine wilt disease, has phytophagous and mycetophagous phases during its life cycle. This highly unusual feature distinguishes it from other plant-parasitic nematodes and requires profound changes in biology between modes. During the phytophagous stage, the nematode migrates within pine trees, feeding on the contents of parenchymal cells. Like other plant pathogens, B. xylophilus secretes effectors from pharyngeal gland cells into the host during infection. We provide the first description of changes in the morphology of these gland cells between juvenile and adult life stages. Using a comparative transcriptomics approach and an effector identification pipeline, we identify numerous novel parasitism genes which may be important for the mediation of interactions of B. xylophilus with its host. In-depth characterization of all parasitism genes using in situ hybridization reveals two major categories of detoxification proteins, those specifically expressed in either the pharyngeal gland cells or the digestive system. These data suggest that B. xylophilus incorporates effectors in a multilayer detoxification strategy in order to protect itself from host defence responses during phytophagy. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  19. Genome scans on experimentally evolved populations reveal candidate regions for adaptation to plant resistance in the potato cyst nematode Globodera pallida.

    Science.gov (United States)

    Eoche-Bosy, D; Gautier, M; Esquibet, M; Legeai, F; Bretaudeau, A; Bouchez, O; Fournet, S; Grenier, E; Montarry, J

    2017-09-01

    Improving resistance durability involves to be able to predict the adaptation speed of pathogen populations. Identifying the genetic bases of pathogen adaptation to plant resistances is a useful step to better understand and anticipate this phenomenon. Globodera pallida is a major pest of potato crop for which a resistance QTL, GpaV vrn , has been identified in Solanum vernei. However, its durability is threatened as G. pallida populations are able to adapt to the resistance in few generations. The aim of this study was to investigate the genomic regions involved in the resistance breakdown by coupling experimental evolution and high-density genome scan. We performed a whole-genome resequencing of pools of individuals (Pool-Seq) belonging to G. pallida lineages derived from two independent populations having experimentally evolved on susceptible and resistant potato cultivars. About 1.6 million SNPs were used to perform the genome scan using a recent model testing for adaptive differentiation and association to population-specific covariables. We identified 275 outliers and 31 of them, which also showed a significant reduction in diversity in adapted lineages, were investigated for their genic environment. Some candidate genomic regions contained genes putatively encoding effectors and were enriched in SPRYSECs, known in cyst nematodes to be involved in pathogenicity and in (a)virulence. Validated candidate SNPs will provide a useful molecular tool to follow frequencies of virulence alleles in natural G. pallida populations and define efficient strategies of use of potato resistances maximizing their durability. © 2017 John Wiley & Sons Ltd.

  20. Comparing different maize supplementation strategies to improve resilience and resistance against gastrointestinal nematode infections in browsing goats.

    Science.gov (United States)

    Gárate-Gallardo, Leslie; Torres-Acosta, Juan Felipe de Jesús; Aguilar-Caballero, Armando Jacinto; Sandoval-Castro, Carlos Alfredo; Cámara-Sarmiento, Ramón; Canul-Ku, Hilda Lorena

    2015-01-01

    The effect of maize grain supplementation on the resilience and resistance of browsing Criollo goat kids against gastrointestinal nematodes was evaluated. Five-month-old kids (n = 42), raised worm-free, were allocated to five groups: infected + not supplemented (I-NS; n = 10), infected + maize supplement at 108 g/d (I-S108; n = 8), maize supplement at 1% of body weight (BW) (I-S1%; n = 8), maize supplement at 1.5% BW (I-S1.5%; n = 8), or infected + supplemented (maize supplement 1.5% BW) + moxidectin (0.2 mg/kg BW subcutaneously every 28 d) (T-S1.5%; n = 8). Kids browsed daily (7 h) in a tropical forest for 112 days during the rainy season. Kids were weighed weekly to adjust supplementary feeding. Hematocrit (Ht), hemoglobin (Hb), and eggs per gram of feces were determined fortnightly. On day 112, five goat kids were slaughtered per group to determine worm burdens. Kids of the I-S1.5% group showed similar body-weight change, Ht and Hb, compared to kids without gastrointestinal nematodes (T-S1.5%), as well as lower eggs per gram of feces and Trichostrongylus colubriformis worm burden compared to the I-NS group (P > 0.05). Thus, among the supplement levels tested, increasing maize supplementation at 1.5% BW of kids was the best strategy to improve their resilience and resistance against natural gastrointestinal nematode infections under the conditions of forage from the tropical forest. © L. Gárate-Gallardo et al., published by EDP Sciences, 2015.

  1. Discrimination of gastrointestinal nematode eggs from crude fecal egg preparations by inhibitor-resistant conventional and real-time PCR.

    Directory of Open Access Journals (Sweden)

    Janina Demeler

    Full Text Available Diagnosis of gastrointestinal nematodes relies predominantly on coproscopic methods such as flotation, Kato-Katz, McMaster or FLOTAC. Although FLOTAC allows accurate quantification, many nematode eggs can only be differentiated to genus or family level. Several molecular diagnostic tools discriminating closely related species suffer from high costs for DNA isolation from feces and limited sensitivity since most kits use only small amounts of feces (<1 g. A direct PCR from crude egg preparations was designed for full compatibility with FLOTAC to accurately quantify eggs per gram feces (epg and determine species composition. Eggs were recovered from the flotation solution and concentrated by sieving. Lysis was achieved by repeated boiling and freezing cycles - only Trichuris eggs required additional mechanic disruption. Egg lysates were directly used as template for PCR with Phusion DNA polymerase which is particularly resistant to PCR inhibitors. Qualitative results were obtained with feces of goats, cattle, horses, swine, cats, dogs and mice. The finally established protocol was also compatible with quantitative real-time PCR in the presence of EvaGreen and no PCR inhibition was detectable when extracts were diluted at least fourfold. Sensitivity was comparable to DNA isolation protocols and spiked samples with five epg were reliably detected. For Toxocara cati a detection limit below one epg was demonstrated. It was possible to distinguish T. cati and Toxocara canis using high resolution melt (HRM analysis, a rapid tool for species identification. In human samples, restriction fragment length polymorphism (RFLP and HRM analysis were used to discriminate Necator americanus and Ancylostoma duodenale. The method is able to significantly improve molecular diagnosis of gastrointestinal nematodes by increasing speed and sensitivity while decreasing overall costs. For identification of species or resistance alleles, analysis of PCR products with many

  2. Discrimination of gastrointestinal nematode eggs from crude fecal egg preparations by inhibitor-resistant conventional and real-time PCR.

    Science.gov (United States)

    Demeler, Janina; Ramünke, Sabrina; Wolken, Sonja; Ianiello, Davide; Rinaldi, Laura; Gahutu, Jean Bosco; Cringoli, Giuseppe; von Samson-Himmelstjerna, Georg; Krücken, Jürgen

    2013-01-01

    Diagnosis of gastrointestinal nematodes relies predominantly on coproscopic methods such as flotation, Kato-Katz, McMaster or FLOTAC. Although FLOTAC allows accurate quantification, many nematode eggs can only be differentiated to genus or family level. Several molecular diagnostic tools discriminating closely related species suffer from high costs for DNA isolation from feces and limited sensitivity since most kits use only small amounts of feces (PCR from crude egg preparations was designed for full compatibility with FLOTAC to accurately quantify eggs per gram feces (epg) and determine species composition. Eggs were recovered from the flotation solution and concentrated by sieving. Lysis was achieved by repeated boiling and freezing cycles - only Trichuris eggs required additional mechanic disruption. Egg lysates were directly used as template for PCR with Phusion DNA polymerase which is particularly resistant to PCR inhibitors. Qualitative results were obtained with feces of goats, cattle, horses, swine, cats, dogs and mice. The finally established protocol was also compatible with quantitative real-time PCR in the presence of EvaGreen and no PCR inhibition was detectable when extracts were diluted at least fourfold. Sensitivity was comparable to DNA isolation protocols and spiked samples with five epg were reliably detected. For Toxocara cati a detection limit below one epg was demonstrated. It was possible to distinguish T. cati and Toxocara canis using high resolution melt (HRM) analysis, a rapid tool for species identification. In human samples, restriction fragment length polymorphism (RFLP) and HRM analysis were used to discriminate Necator americanus and Ancylostoma duodenale. The method is able to significantly improve molecular diagnosis of gastrointestinal nematodes by increasing speed and sensitivity while decreasing overall costs. For identification of species or resistance alleles, analysis of PCR products with many different post PCR methods can

  3. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    Directory of Open Access Journals (Sweden)

    Etienne G.J. Danchin

    2017-10-01

    Full Text Available Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus, representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus, respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.

  4. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    Science.gov (United States)

    Danchin, Etienne G.J.; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Sokolova (Guzeeva), Elena; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T.

    2017-01-01

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus, representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus, respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum. PMID:29065523

  5. Sequence variation in mitochondrial cox1 and nad1 genes of ascaridoid nematodes in cats and dogs from Iran.

    Science.gov (United States)

    Mikaeili, F; Mirhendi, H; Mohebali, M; Hosseini, M; Sharbatkhori, M; Zarei, Z; Kia, E B

    2015-07-01

    The study was conducted to determine the sequence variation in two mitochondrial genes, namely cytochrome c oxidase 1 (pcox1) and NADH dehydrogenase 1 (pnad1) within and among isolates of Toxocara cati, Toxocara canis and Toxascaris leonina. Genomic DNA was extracted from 32 isolates of T. cati, 9 isolates of T. canis and 19 isolates of T. leonina collected from cats and dogs in different geographical areas of Iran. Mitochondrial genes were amplified by polymerase chain reaction (PCR) and sequenced. Sequence data were aligned using the BioEdit software and compared with published sequences in GenBank. Phylogenetic analysis was performed using Bayesian inference and maximum likelihood methods. Based on pairwise comparison, intra-species genetic diversity within Iranian isolates of T. cati, T. canis and T. leonina amounted to 0-2.3%, 0-1.3% and 0-1.0% for pcox1 and 0-2.0%, 0-1.7% and 0-2.6% for pnad1, respectively. Inter-species sequence variation among the three ascaridoid nematodes was significantly higher, being 9.5-16.6% for pcox1 and 11.9-26.7% for pnad1. Sequence and phylogenetic analysis of the pcox1 and pnad1 genes indicated that there is significant genetic diversity within and among isolates of T. cati, T. canis and T. leonina from different areas of Iran, and these genes can be used for studying genetic variation of ascaridoid nematodes.

  6. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes.

    Science.gov (United States)

    Rybarczyk-Mydłowska, Katarzyna; Maboreke, Hazel Ruvimbo; van Megen, Hanny; van den Elsen, Sven; Mooyman, Paul; Smant, Geert; Bakker, Jaap; Helder, Johannes

    2012-11-21

    Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5) cellulases are relatively well characterized, especially for high impact parasites such as root-knot and cyst nematodes. Interestingly, ancestors of extant nematodes most likely acquired these GHF5 cellulases from a prokaryote donor by one or multiple lateral gene transfer events. To obtain insight into the origin of GHF5 cellulases among evolutionary advanced members of the order Tylenchida, cellulase biodiversity data from less distal family members were collected and analyzed. Single nematodes were used to obtain (partial) genomic sequences of cellulases from representatives of the genera Meloidogyne, Pratylenchus, Hirschmanniella and Globodera. Combined Bayesian analysis of ≈ 100 cellulase sequences revealed three types of catalytic domains (A, B, and C). Represented by 84 sequences, type B is numerically dominant, and the overall topology of the catalytic domain type shows remarkable resemblance with trees based on neutral (= pathogenicity-unrelated) small subunit ribosomal DNA sequences. Bayesian analysis further suggested a sister relationship between the lesion nematode Pratylenchus thornei and all type B cellulases from root-knot nematodes. Yet, the relationship between the three catalytic domain types remained unclear. Superposition of intron data onto the cellulase tree suggests that types B and C are related, and together distinct from type A that is characterized by two unique introns. All Tylenchida members investigated here harbored one or multiple GHF5 cellulases. Three types of catalytic domains are distinguished, and the presence of at least two types is relatively common among plant parasitic Tylenchida. Analysis of coding sequences of cellulases suggests that root-knot and cyst nematodes did not acquire this gene directly

  7. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes

    Directory of Open Access Journals (Sweden)

    Rybarczyk-Mydłowska Katarzyna

    2012-11-01

    Full Text Available Abstract Background Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5 cellulases are relatively well characterized, especially for high impact parasites such as root-knot and cyst nematodes. Interestingly, ancestors of extant nematodes most likely acquired these GHF5 cellulases from a prokaryote donor by one or multiple lateral gene transfer events. To obtain insight into the origin of GHF5 cellulases among evolutionary advanced members of the order Tylenchida, cellulase biodiversity data from less distal family members were collected and analyzed. Results Single nematodes were used to obtain (partial genomic sequences of cellulases from representatives of the genera Meloidogyne, Pratylenchus, Hirschmanniella and Globodera. Combined Bayesian analysis of ≈ 100 cellulase sequences revealed three types of catalytic domains (A, B, and C. Represented by 84 sequences, type B is numerically dominant, and the overall topology of the catalytic domain type shows remarkable resemblance with trees based on neutral (= pathogenicity-unrelated small subunit ribosomal DNA sequences. Bayesian analysis further suggested a sister relationship between the lesion nematode Pratylenchus thornei and all type B cellulases from root-knot nematodes. Yet, the relationship between the three catalytic domain types remained unclear. Superposition of intron data onto the cellulase tree suggests that types B and C are related, and together distinct from type A that is characterized by two unique introns. Conclusions All Tylenchida members investigated here harbored one or multiple GHF5 cellulases. Three types of catalytic domains are distinguished, and the presence of at least two types is relatively common among plant parasitic Tylenchida. Analysis of coding sequences of cellulases suggests that root

  8. Transcriptome Sequencing Analysis and Functional Identification of Sex Differentiation Genes from the Mosquito Parasitic Nematode, Romanomermis wuchangensis.

    Directory of Open Access Journals (Sweden)

    Mingyue Duan

    Full Text Available Mosquito-transmitted diseases like malaria and dengue fever are global problem and an estimated 50-100 million of dengue or dengue hemorrhagic fever cases are reported worldwide every year. The mermithid nematode Romanomermis wuchangensis has been successfully used as an ecosystem-friendly biocontrol agent for mosquito prevention in laboratory studies. However, this nematode can not undergo sex differentiation in vitro culture, which has seriously affected their application of biocontrol in the field. In this study, based on transcriptome sequencing analysis of R. wuchangensis, Rwucmab-3, Rwuclaf-1 and Rwuctra-2 were cloned and used to investigate molecular regulatory function of sex differentiation. qRT-PCR results demonstrated that the expression level of Rwucmab-3 between male and female displayed obvious difference on the 3rd day of parasitic stage, which was earlier than Rwuclaf-1 and Rwuctra-2, highlighting sex differentiation process may start on the 3rd day of parasitic stage. Besides, FITC was used as a marker to test dsRNA uptake efficiency of R. wuchangensis, which fluorescence intensity increased with FITC concentration after 16 h incubation, indicating this nematode can successfully ingest soaking solution via its cuticle. RNAi results revealed the sex ratio of R. wuchangensis from RNAi treated groups soaked in dsRNA of Rwucmab-3 was significantly higher than gfp dsRNA treated groups and control groups, highlighting RNAi of Rwumab-3 may hinder the development of male nematodes. These results suggest that Rwucmab-3 mainly involves in the initiation of sex differentiation and the development of male sexual dimorphism. Rwuclaf-1 and Rwuctra-2 may play vital role in nematode reproductive and developmental system. In conclusion, transcript sequences presented in this study could provide more bioinformatics resources for future studies on gene cloning and other molecular regulatory mechanism in R. wuchangensis. Moreover, identification

  9. Divergent expression of cytokinin biosynthesis, signaling and catabolism genes underlying differences in feeding sites induced by cyst and root-knot nematodes.

    Science.gov (United States)

    Dowd, Carola D; Chronis, Demosthenis; Radakovic, Zoran S; Siddique, Shahid; Schmülling, Thomas; Werner, Tomáš; Kakimoto, Tatsuo; Grundler, Florian M W; Mitchum, Melissa G

    2017-10-01

    Cyst and root-knot nematodes are obligate parasites of economic importance with a remarkable ability to reprogram root cells into unique metabolically active feeding sites. Previous studies have suggested a role for cytokinin in feeding site formation induced by these two types of nematodes, but the mechanistic details have not yet been described. Using Arabidopsis as a host plant species, we conducted a comparative analysis of cytokinin genes in response to the beet cyst nematode (BCN), Heterodera schachtii, and the root-knot nematode (RKN), Meloidogyne incognita. We identified distinct differences in the expression of cytokinin biosynthesis, catabolism and signaling genes in response to infection by BCN and RKN, suggesting differential manipulation of the cytokinin pathway by these two nematode species. Furthermore, we evaluated Arabidopsis histidine kinase receptor mutant lines ahk2/3, ahk2/4 and ahk3/4 in response to RKN infection. Similar to our previous studies with BCN, these lines were significantly less susceptible to RKN without compromising nematode penetration, suggesting a requirement of cytokinin signaling in RKN feeding site formation. Moreover, an analysis of ahk double mutants using CycB1;1:GUS/ahk introgressed lines revealed contrasting differences in the cytokinin receptors mediating cell cycle activation in feeding sites induced by BCN and RKN. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  10. Investigation on the infection mechanism of the fungus Clonostachys rosea against nematodes using the green fluorescent protein.

    Science.gov (United States)

    Zhang, Lin; Yang, Jinkui; Niu, Qiuhong; Zhao, Xuna; Ye, Fengping; Liang, Lianming; Zhang, Ke-Qin

    2008-04-01

    The fungus Clonostachys rosea (syn. Gliocladium roseum) is a potential biocontrol agent. It can suppress the sporulation of the plant pathogenic fungus Botrytis cinerea and kill pathogenic nematodes, but the process of nematode pathogenesis is poorly understood. To help understand the underlying mechanism, we constructed recombinant strains containing a plasmid with both the enhanced green fluorescent protein gene egfp and the hygromycin resistance gene hph. Expression of the green fluorescent protein (GFP) was monitored using fluorescence microscopy. Our observations reveal that the pathogenesis started from the adherence of conidia to nematode cuticle for germination, followed by the penetration of germ tubes into the nematode body and subsequent death and degradation of the nematodes. These are the first findings on the infection process of the fungal pathogen marked with GFP, and the developed method can become an important tool for studying the molecular mechanisms of nematode infection by C. rosea.

  11. Screening of non-tuber bearing Solanaceae for resistance to and induction of juvenile hatch of potato cyst nematodes and their potential for trap cropping

    NARCIS (Netherlands)

    Scholte, K.

    2000-01-01

    Ninety accessions of non-tuber bearing Solanaceae were screened for (i) resistance to and (ii) stimulatory effect on juvenile hatch of potato cyst nematodes, and (iii) their growth under temperate climatic conditions. All plant species belonging to the genus Solanum tested induced hatching but this

  12. Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species

    Science.gov (United States)

    To Identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode and fungal disease resistance traits, a series of interspecific cotton (Gossypium spp.) chromosome substitution (CS) lines were used in this study. The CS lines were developed in ...

  13. Transgenic soybean overexpressing GmSamT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines

    Science.gov (United States)

    Soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyzes the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heter...

  14. Identification of acquired antimicrobial resistance genes

    DEFF Research Database (Denmark)

    Zankari, Ea; Hasman, Henrik; Cosentino, Salvatore

    2012-01-01

    ObjectivesIdentification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. As the costs of whole-genome sequencing (WGS) continue to decline, it becomes increasingly available in routine diagnostic laborato......ObjectivesIdentification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. As the costs of whole-genome sequencing (WGS) continue to decline, it becomes increasingly available in routine diagnostic...... laboratories and is anticipated to substitute traditional methods for resistance gene identification. Thus, the current challenge is to extract the relevant information from the large amount of generated data.MethodsWe developed a web-based method, ResFinder that uses BLAST for identification of acquired...... antimicrobial resistance genes in whole-genome data. As input, the method can use both pre-assembled, complete or partial genomes, and short sequence reads from four different sequencing platforms. The method was evaluated on 1862 GenBank files containing 1411 different resistance genes, as well as on 23 de...

  15. Molecular contest between potato and the potato cyst nematode Globodera pallida: modulation of Gpa2-mediated resistance

    NARCIS (Netherlands)

    Koropacka, K.B.

    2010-01-01

    Gpa2 recognition specificity
    Among all the multicellular animals, nematodes are the most numerous. In soil, a high variety
    of free living nematodes feeding on bacteria can be found as well as species that parasitize
    insects, animals or plants. The potato cyst nematode (PCN)

  16. A high-resolution map of the Grp1 locus on chromosome V of potato harbouring broad-spectrum resistance to the cyst nematode species Globodera pallida and Globodera rostochiensis.

    Science.gov (United States)

    Finkers-Tomczak, Anna; Danan, Sarah; van Dijk, Thijs; Beyene, Amelework; Bouwman, Liesbeth; Overmars, Hein; van Eck, Herman; Goverse, Aska; Bakker, Jaap; Bakker, Erin

    2009-06-01

    The Grp1 locus confers broad-spectrum resistance to the potato cyst nematode species Globodera pallida and Globodera rostochiensis and is located in the GP21-GP179 interval on the short arm of chromosome V of potato. A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes. The flanking markers GP21 and GP179 have been used to screen the 1,536 genotypes for recombination events. Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432. Detailed analysis of the 44 recombinant genotypes showed that G. pallida and G. rostochiensis resistance could not be separated and map to the same location between marker SPUD838 and TG432. It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class.

  17. Resistance Genes in Global Crop Breeding Networks.

    Science.gov (United States)

    Garrett, K A; Andersen, K F; Asche, F; Bowden, R L; Forbes, G A; Kulakow, P A; Zhou, B

    2017-10-01

    Resistance genes are a major tool for managing crop diseases. The networks of crop breeders who exchange resistance genes and deploy them in varieties help to determine the global landscape of resistance and epidemics, an important system for maintaining food security. These networks function as a complex adaptive system, with associated strengths and vulnerabilities, and implications for policies to support resistance gene deployment strategies. Extensions of epidemic network analysis can be used to evaluate the multilayer agricultural networks that support and influence crop breeding networks. Here, we evaluate the general structure of crop breeding networks for cassava, potato, rice, and wheat. All four are clustered due to phytosanitary and intellectual property regulations, and linked through CGIAR hubs. Cassava networks primarily include public breeding groups, whereas others are more mixed. These systems must adapt to global change in climate and land use, the emergence of new diseases, and disruptive breeding technologies. Research priorities to support policy include how best to maintain both diversity and redundancy in the roles played by individual crop breeding groups (public versus private and global versus local), and how best to manage connectivity to optimize resistance gene deployment while avoiding risks to the useful life of resistance genes. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

  18. Weight gain and resistance to gastrointestinal nematode infections in two genetically diverse groups of cattle.

    Science.gov (United States)

    Höglund, Johan; Hessle, Anna; Zaralis, Konstantinos; Arvidsson-Segerkvist, Katarina; Athanasiadou, Spiridoula

    2018-01-15

    Body weight gain (BWG) and gastrointestinal nematode challenge (GIN) were investigated in two genetically diverse groups of cattle. Thirty-two dairy calves (D=Swedish Red/Holstein) and 31 dairy×beef crosses (C=Swedish Red/Holstein×Charolais) pairwise matched by dam breed and birth dates, were monitored for ≈20 weeks on a pasture grazed by cattle in the previous year. At turn-out, animals (between 6 and 12 months age) from each genotype were either infected with 5000 third stage (L3) Ostertagia ostertagi (50%) and Cooperia oncophora (50%) larvae (H, high-exposure); or treated monthly with 0.5mg ivermectin (Noromectin ® , Pour-on) per kg bodyweight to remove worms ingested (L, low-exposure). Animals were weighed every fortnight and individual BWG was calculated. Faecal and blood samples were collected every four weeks throughout the experiment for nematode faecal egg counts (FEC) and larvae cultures and serum pepsinogen concentrations (SPC), respectively. Nematode eggs were observed 29 days post turn-out in both H groups. FEC peaked to around 200 eggs per gram (epg) on days 58 and 85 respectively in both H groups. FEC were also observed in the L groups at the same time, but mean epg remained very low (3.5 IU tyrosine whereas only six DH animals reached similar pepsinogen levels. The level of infection (H and L) significantly affected BWG in both genotypes. Even though there was no statistically significant genotype (C or D)×treatment (H or L) interaction, there was a larger difference in body weight of H and L in C (37kg) compared to D (17kg) genotypes at the end of the experiment. Our data collectively support the view crossbred (C) animals experience the impact of gastrointestinal parasitism more severely compared to pure dairy (D) first season grazers. The mechanisms that underpin this remains speculative. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. The map-1 gene family in root-knot nematodes, Meloidogyne spp.: a set of taxonomically restricted genes specific to clonal species.

    Directory of Open Access Journals (Sweden)

    Iva Tomalova

    Full Text Available Taxonomically restricted genes (TRGs, i.e., genes that are restricted to a limited subset of phylogenetically related organisms, may be important in adaptation. In parasitic organisms, TRG-encoded proteins are possible determinants of the specificity of host-parasite interactions. In the root-knot nematode (RKN Meloidogyne incognita, the map-1 gene family encodes expansin-like proteins that are secreted into plant tissues during parasitism, thought to act as effectors to promote successful root infection. MAP-1 proteins exhibit a modular architecture, with variable number and arrangement of 58 and 13-aa domains in their central part. Here, we address the evolutionary origins of this gene family using a combination of bioinformatics and molecular biology approaches. Map-1 genes were solely identified in one single member of the phylum Nematoda, i.e., the genus Meloidogyne, and not detected in any other nematode, thus indicating that the map-1 gene family is indeed a TRG family. A phylogenetic analysis of the distribution of map-1 genes in RKNs further showed that these genes are specifically present in species that reproduce by mitotic parthenogenesis, with the exception of M. floridensis, and could not be detected in RKNs reproducing by either meiotic parthenogenesis or amphimixis. These results highlight the divergence between mitotic and meiotic RKN species as a critical transition in the evolutionary history of these parasites. Analysis of the sequence conservation and organization of repeated domains in map-1 genes suggests that gene duplication(s together with domain loss/duplication have contributed to the evolution of the map-1 family, and that some strong selection mechanism may be acting upon these genes to maintain their functional role(s in the specificity of the plant-RKN interactions.

  20. A SNARE-Like Protein and Biotin Are Implicated in Soybean Cyst Nematode Virulence.

    Directory of Open Access Journals (Sweden)

    Sadia Bekal

    Full Text Available 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.

  1. The receptor like kinase at Rhg1-a/Rfs2 caused pleiotropic resistance to sudden death syndrome and soybean cyst nematode as a transgene by altering signaling responses.

    Science.gov (United States)

    Srour, Ali; Afzal, Ahmed J; Blahut-Beatty, Laureen; Hemmati, Naghmeh; Simmonds, Daina H; Li, Wenbin; Liu, Miao; Town, Christopher D; Sharma, Hemlata; Arelli, Prakash; Lightfoot, David A

    2012-08-02

    Soybean (Glycine max (L. Merr.)) resistance to any population of Heterodera glycines (I.), or Fusarium virguliforme (Akoi, O'Donnell, Homma & Lattanzi) required a functional allele at Rhg1/Rfs2. H. glycines, the soybean cyst nematode (SCN) was an ancient, endemic, pest of soybean whereas F. virguliforme causal agent of sudden death syndrome (SDS), was a recent, regional, pest. This study examined the role of a receptor like kinase (RLK) GmRLK18-1 (gene model Glyma_18_02680 at 1,071 kbp on chromosome 18 of the genome sequence) within the Rhg1/Rfs2 locus in causing resistance to SCN and SDS. A BAC (B73p06) encompassing the Rhg1/Rfs2 locus was sequenced from a resistant cultivar and compared to the sequences of two susceptible cultivars from which 800 SNPs were found. Sequence alignments inferred that the resistance allele was an introgressed region of about 59 kbp at the center of which the GmRLK18-1 was the most polymorphic gene and encoded protein. Analyses were made of plants that were either heterozygous at, or transgenic (and so hemizygous at a new location) with, the resistance allele of GmRLK18-1. Those plants infested with either H. glycines or F. virguliforme showed that the allele for resistance was dominant. In the absence of Rhg4 the GmRLK18-1 was sufficient to confer nearly complete resistance to both root and leaf symptoms of SDS caused by F. virguliforme and provided partial resistance to three different populations of nematodes (mature female cysts were reduced by 30-50%). In the presence of Rhg4 the plants with the transgene were nearly classed as fully resistant to SCN (females reduced to 11% of the susceptible control) as well as SDS. A reduction in the rate of early seedling root development was also shown to be caused by the resistance allele of the GmRLK18-1. Field trials of transgenic plants showed an increase in foliar susceptibility to insect herbivory. The inference that soybean has adapted part of an existing pathogen recognition and

  2. The receptor like kinase at Rhg1-a/Rfs2 caused pleiotropic resistance to sudden death syndrome and soybean cyst nematode as a transgene by altering signaling responses

    Directory of Open Access Journals (Sweden)

    Srour Ali

    2012-08-01

    Full Text Available Abstract Background Soybean (Glycine max (L. Merr. resistance to any population of Heterodera glycines (I., or Fusarium virguliforme (Akoi, O’Donnell, Homma & Lattanzi required a functional allele at Rhg1/Rfs2. H. glycines, the soybean cyst nematode (SCN was an ancient, endemic, pest of soybean whereas F. virguliforme causal agent of sudden death syndrome (SDS, was a recent, regional, pest. This study examined the role of a receptor like kinase (RLK GmRLK18-1 (gene model Glyma_18_02680 at 1,071 kbp on chromosome 18 of the genome sequence within the Rhg1/Rfs2 locus in causing resistance to SCN and SDS. Results A BAC (B73p06 encompassing the Rhg1/Rfs2 locus was sequenced from a resistant cultivar and compared to the sequences of two susceptible cultivars from which 800 SNPs were found. Sequence alignments inferred that the resistance allele was an introgressed region of about 59 kbp at the center of which the GmRLK18-1 was the most polymorphic gene and encoded protein. Analyses were made of plants that were either heterozygous at, or transgenic (and so hemizygous at a new location with, the resistance allele of GmRLK18-1. Those plants infested with either H. glycines or F. virguliforme showed that the allele for resistance was dominant. In the absence of Rhg4 the GmRLK18-1 was sufficient to confer nearly complete resistance to both root and leaf symptoms of SDS caused by F. virguliforme and provided partial resistance to three different populations of nematodes (mature female cysts were reduced by 30–50%. In the presence of Rhg4 the plants with the transgene were nearly classed as fully resistant to SCN (females reduced to 11% of the susceptible control as well as SDS. A reduction in the rate of early seedling root development was also shown to be caused by the resistance allele of the GmRLK18-1. Field trials of transgenic plants showed an increase in foliar susceptibility to insect herbivory. Conclusions The inference that soybean has

  3. Functional comparison of the nematode Hox gene lin-39 in C. elegans and P. pacificus reveals evolutionary conservation of protein function despite divergence of primary sequences

    OpenAIRE

    Grandien, Kaj; Sommer, Ralf J.

    2001-01-01

    Hox transcription factors have been implicated in playing a central role in the evolution of animal morphology. Many studies indicate the evolutionary importance of regulatory changes in Hox genes, but little is known about the role of functional changes in Hox proteins. In the nematodes Pristionchus pacificus and Caenorhabditis elegans, developmental processes can be compared at the cellular, genetic, and molecular levels and differences in gene function can be identified. The Hox gene lin-3...

  4. The evolutionary position of nematodes

    Directory of Open Access Journals (Sweden)

    Gojobori Takashi

    2002-04-01

    Full Text Available Abstract Background The complete genomes of three animals have been sequenced by global research efforts: a nematode worm (Caenorhabditis elegans, an insect (Drosophila melanogaster, and a vertebrate (Homo sapiens. Remarkably, their relationships have yet to be clarified. The confusion concerns the enigmatic position of nematodes. Traditionally, nematodes have occupied a basal position, in part because they lack a true body cavity. However, the leading hypothesis now joins nematodes with arthropods in a molting clade, Ecdysozoa, based on data from several genes. Results We tested the Ecdysozoa hypothesis with analyses of more than 100 nuclear protein alignments, under conditions that would expose biases, and found that it was not supported. Instead, we found significant support for the traditional hypothesis, Coelomata. Our result is robust to different rates of sequence change among genes and lineages, different numbers of taxa, and different species of nematodes. Conclusion We conclude that insects (arthropods are genetically and evolutionarily closer to humans than to nematode worms.

  5. Transcriptome-wide selection of a reliable set of reference genes for gene expression studies in potato cyst nematodes (Globodera spp.).

    Science.gov (United States)

    Sabeh, Michael; Duceppe, Marc-Olivier; St-Arnaud, Marc; Mimee, Benjamin

    2018-01-01

    Relative gene expression analyses by qRT-PCR (quantitative reverse transcription PCR) require an internal control to normalize the expression data of genes of interest and eliminate the unwanted variation introduced by sample preparation. A perfect reference gene should have a constant expression level under all the experimental conditions. However, the same few housekeeping genes selected from the literature or successfully used in previous unrelated experiments are often routinely used in new conditions without proper validation of their stability across treatments. The advent of RNA-Seq and the availability of public datasets for numerous organisms are opening the way to finding better reference genes for expression studies. Globodera rostochiensis is a plant-parasitic nematode that is particularly yield-limiting for potato. The aim of our study was to identify a reliable set of reference genes to study G. rostochiensis gene expression. Gene expression levels from an RNA-Seq database were used to identify putative reference genes and were validated with qRT-PCR analysis. Three genes, GR, PMP-3, and aaRS, were found to be very stable within the experimental conditions of this study and are proposed as reference genes for future work.

  6. Motility in the L3 stage is a poor phenotype for detecting and measuring resistance to avermectin/milbemycin drugs in gastrointestinal nematodes of livestock

    Directory of Open Access Journals (Sweden)

    Melissa M. George

    2018-04-01

    Full Text Available Motility is a commonly used in vitro phenotype for assessing anthelmintic activity of candidate compounds, and for detecting anthelmintic resistance in nematodes. Third-stage larvae (L3 of parasitic nematodes are commonly used in motility-based assays because L3 are simple to obtain and can remain viable in storage for extended periods. To improve the measurement of motility of microscopic stages of nematodes, our laboratory developed the Worminator, which quantitatively measures motility of parasites. Using the Worminator, we compared the dose-response characteristics of several avermectin/milbemycin (AM compounds using L3 from both AM-susceptible and AM-resistant Cooperia spp. (abamectin, doramectin, eprinomectin, ivermectin, moxidectin and Haemonchus contortus (eprinomectin, ivermectin, moxidectin. Concentrations tested with the Worminator ranged from 0.156 to 40 μM. Differences in EC50 between AM-susceptible and AM-resistant isolates of Cooperia spp. and Haemonchus contortus were small, with resistance ratios ranging from 1.00 to 1.34 for Cooperia spp., 0.99 to 1.65 for Haemonchus contortus. Larval migration inhibition assays were conducted using the same isolates and were equally ineffective for detection of resistance with resistance ratios less than 2.0. These results contrast with those of the Larval Development Assay where we obtained a resistance ratio of 16.48 using the same isolates of Haemonchus contortus. Moreover, even at the highest concentration tested (40 μM, 100% inhibition of motility was never achieved and EC50 for Worminator assays were more than 100× higher than peak plasma levels achieved in vivo following treatment. These data demonstrate that dose-response characteristics for inhibition of motility in L3 of gastrointestinal nematodes of livestock do not significantly differ for AM-susceptible and AM-resistant isolates. These data challenge the suitability of motility as a phenotype for detecting and measuring

  7. Evaluation of different models to segregate Pelibuey and Katahdin ewes into resistant or susceptible to gastrointestinal nematodes.

    Science.gov (United States)

    Palomo-Couoh, Jovanny Gaspar; Aguilar-Caballero, Armando Jacinto; Torres-Acosta, Juan Felipe de Jesús; Magaña-Monforte, Juan Gabriel

    2016-12-01

    This study evaluated four models based on the number of eggs per gram of faeces (EPG) to segregate Pelibuey or Katahdin ewes during the lactation period into resistant or susceptible to gastrointestinal nematodes (GIN) in tropical Mexico. Nine hundred and thirty EPG counts of Pelibuey ewes and 710 of Katahdin ewes were obtained during 10 weeks of lactation. Ewes were segregated into resistant, intermediate and susceptible, using their individual EPG every week. Then, data of every ewe was used to provide a reference classification, which included all the EPG values of each animal. Then, four models were evaluated against such reference. Model 1 was based on the 10-week mean EPG count ± 2 SE. Models 2, 3 and 4 were based on the mean EPG count of 10, 5 and 2 weeks of lactation. The cutoff points for the segregation of ewe in those three models were the quartiles ≤Q1 (low elimination) and ≥Q3 (high elimination). In all the models evaluated, the ewes classified as resistant had lower EPG than intermediates and susceptible (P ewes classified as susceptible had higher EPG than intermediate and resistant (P 70 %). Model 3 tended to show higher sensitivity and specificity with the reference data, but no difference was found with other models. The present study showed that the phenotypic marker EPG might serve to identify and segregate populations of adult ewes during the lactation period. All models used served to segregate Pelibuey and Katahdin ewes into resistant, intermediate and susceptible. The model 3 (mean of 5 weeks) could be used because it required less sampling effort without losing sensitivity or specificity in the segregation of animals. However, model 2 (mean of 2 weeks) was less labour-intensive.

  8. Expression Study of Banana Pathogenic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Fenny M. Dwivany

    2016-10-01

    Full Text Available Banana is one of the world's most important trade commodities. However, infection of banana pathogenic fungi (Fusarium oxysporum race 4 is one of the major causes of decreasing production in Indonesia. Genetic engineering has become an alternative way to control this problem by isolating genes that involved in plant defense mechanism against pathogens. Two of the important genes are API5 and ChiI1, each gene encodes apoptosis inhibitory protein and chitinase enzymes. The purpose of this study was to study the expression of API5 and ChiI1 genes as candidate pathogenic resistance genes. The amplified fragments were then cloned, sequenced, and confirmed with in silico studies. Based on sequence analysis, it is showed that partial API5 gene has putative transactivation domain and ChiI1 has 9 chitinase family GH19 protein motifs. Data obtained from this study will contribute in banana genetic improvement.

  9. Motility in the L3 stage is a poor phenotype for detecting and measuring resistance to avermectin/milbemycin drugs in gastrointestinal nematodes of livestock.

    Science.gov (United States)

    George, Melissa M; Lopez-Soberal, Lorraine; Storey, Bob E; Howell, Sue B; Kaplan, Ray M

    2018-04-01

    Motility is a commonly used in vitro phenotype for assessing anthelmintic activity of candidate compounds, and for detecting anthelmintic resistance in nematodes. Third-stage larvae (L3) of parasitic nematodes are commonly used in motility-based assays because L3 are simple to obtain and can remain viable in storage for extended periods. To improve the measurement of motility of microscopic stages of nematodes, our laboratory developed the Worminator, which quantitatively measures motility of parasites. Using the Worminator, we compared the dose-response characteristics of several avermectin/milbemycin (AM) compounds using L3 from both AM-susceptible and AM-resistant Cooperia spp. (abamectin, doramectin, eprinomectin, ivermectin, moxidectin) and Haemonchus contortus (eprinomectin, ivermectin, moxidectin). Concentrations tested with the Worminator ranged from 0.156 to 40 μM. Differences in EC 50 between AM-susceptible and AM-resistant isolates of Cooperia spp. and Haemonchus contortus were small, with resistance ratios ranging from 1.00 to 1.34 for Cooperia spp., 0.99 to 1.65 for Haemonchus contortus. Larval migration inhibition assays were conducted using the same isolates and were equally ineffective for detection of resistance with resistance ratios less than 2.0. These results contrast with those of the Larval Development Assay where we obtained a resistance ratio of 16.48 using the same isolates of Haemonchus contortus. Moreover, even at the highest concentration tested (40 μM), 100% inhibition of motility was never achieved and EC 50 for Worminator assays were more than 100× higher than peak plasma levels achieved in vivo following treatment. These data demonstrate that dose-response characteristics for inhibition of motility in L3 of gastrointestinal nematodes of livestock do not significantly differ for AM-susceptible and AM-resistant isolates. These data challenge the suitability of motility as a phenotype for detecting and measuring resistance to AM

  10. The genomic organization of four b-1,4-endoglucanase genes in plant-parasitic cyst nematodes and its evolutionary implications.

    NARCIS (Netherlands)

    Yan, Y.; Smant, G.; Stokkermans, J.P.W.G.; Qin Ling,; Baum, T.J.; Schots, A.; Davis, E.L.

    1998-01-01

    The genomic organization of genes encoding -1,4-endoglucanases (cellulases) from the plant-parasitic cyst nematodes Heterodera glycines and Globodera rostochiensis (HG-eng1, Hg-eng2, GR-eng1, and GR-eng2) was investigated. HG-eng1 and GR-eng1 both contained eight introns and structural domains of

  11. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes

    NARCIS (Netherlands)

    Rybarczyk-Mydlowska, K.D.; Maboreke, H.R.; Megen, van H.H.B.; Elsen, van den S.J.J.; Mooijman, P.J.W.; Smant, G.; Bakker, J.; Helder, J.

    2012-01-01

    Background: Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5) cellulases are relatively well characterized, especially for

  12. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate.

    Science.gov (United States)

    Palomares-Rius, Juan Emilio; Hedley, Pete; Cock, Peter J A; Morris, Jenny A; Jones, John T; Blok, Vivian C

    2016-01-01

    Plant-parasitic nematodes (PPN) need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD) using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD) treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium), while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules).

  13. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate

    Directory of Open Access Journals (Sweden)

    Juan Emilio Palomares-Rius

    2016-02-01

    Full Text Available Plant-parasitic nematodes (PPN need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN (Globodera pallida and G. rostochiensis are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium, while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules.

  14. Lipopolysaccharides of Rhizobium etli strain G12 act in potato roots as an inducing agent of systemic resistance to infection by the cyst nematode Globodera pallida.

    Science.gov (United States)

    Reitz, M; Rudolph, K; Schröder, I; Hoffmann-Hergarten, S; Hallmann, J; Sikora, R A

    2000-08-01

    Recent studies have shown that living and heat-killed cells of the rhizobacterium Rhizobium etli strain G12 induce in potato roots systemic resistance to infection by the potato cyst nematode Globodera pallida. To better understand the mechanisms of induced resistance, we focused on identifying the inducing agent. Since heat-stable bacterial surface carbohydrates such as exopolysaccharides (EPS) and lipopolysaccharides (LPS) are essential for recognition in the symbiotic interaction between Rhizobium and legumes, their role in the R. etli-potato interaction was studied. EPS and LPS were extracted from bacterial cultures, applied to potato roots, and tested for activity as an inducer of plant resistance to the plant-parasitic nematode. Whereas EPS did not affect G. pallida infection, LPS reduced nematode infection significantly in concentrations as low as 1 and 0.1 mg ml(-1). Split-root experiments, guaranteeing a spatial separation of inducing agent and challenging pathogen, showed that soil treatments of one half of the root system with LPS resulted in a highly significant (up to 37%) systemic induced reduction of G. pallida infection of potato roots in the other half. The results clearly showed that LPS of R. etli G12 act as the inducing agent of systemic resistance in potato roots.

  15. Nematode 18S rRNA gene is a reliable tool for environmental biosafety assessment of transgenic banana in confined field trials.

    Science.gov (United States)

    Nakacwa, R; Kiggundu, A; Talwana, H; Namaganda, J; Lilley, C; Tushemereirwe, W; Atkinson, H

    2013-10-01

    Information on relatedness in nematodes is commonly obtained by DNA sequencing of the ribosomal internal transcribed spacer region. However, the level of diversity at this locus is often insufficient for reliable species differentiation. Recent findings suggest that the sequences of a fragment of the small subunit nuclear ribosomal DNA (18S rRNA or SSU), identify genera of soil nematodes and can also distinguish between species in some cases. A database of soil nematode genera in a Ugandan soil was developed using 18S rRNA sequences of individual nematodes from a GM banana confined field trial site at the National Agricultural Research Laboratories, Kawanda in Uganda. The trial was planted to evaluate transgenic bananas for resistance to black Sigatoka disease. Search for relatedness of the sequences gained with entries in a public genomic database identified a range of 20 different genera and sometimes distinguished species. Molecular markers were designed from the sequence information to underpin nematode faunal analysis. This approach provides bio-indicators for disturbance of the soil environment and the condition of the soil food web. It is being developed to support environmental biosafety analysis by detecting any perturbance by transgenic banana or other GM crops on the soil environment.

  16. Life History Responses and Gene Expression Profiles of the Nematode Pristionchus pacificus Cultured on Cryptococcus Yeasts.

    Directory of Open Access Journals (Sweden)

    Gaurav V Sanghvi

    Full Text Available Nematodes, the earth's most abundant metazoa are found in all ecosystems. In order to survive in diverse environments, they have evolved distinct feeding strategies and they can use different food sources. While some nematodes are specialists, including parasites of plants and animals, others such as Pristionchus pacificus are omnivorous feeders, which can live on a diet of bacteria, protozoans, fungi or yeast. In the wild, P. pacificus is often found in a necromenic association with beetles and is known to be able to feed on a variety of microbes as well as on nematode prey. However, in laboratory studies Escherichia coli OP50 has been used as standard food source, similar to investigations in Caenorhabditis elegans and it is unclear to what extent this biases the obtained results and how relevant findings are in real nature. To gain first insight into the variation in traits induced by a non-bacterial food source, we study Pristionchus-fungi interactions under laboratory conditions. After screening different yeast strains, we were able to maintain P. pacificus for at least 50-60 generations on Cryptococcus albidus and Cryptococcus curvatus. We describe life history traits of P. pacificus on both yeast strains, including developmental timing, survival and brood size. Despite a slight developmental delay and problems to digest yeast cells, which are both reflected at a transcriptomic level, all analyses support the potential of Cryptococcus strains as food source for P. pacificus. In summary, our work establishes two Cryptococcus strains as alternative food source for P. pacificus and shows change in various developmental, physiological and morphological traits, including the transcriptomic profiles.

  17. Coupling of MIC-3 overexpression with the chromosome 11 and 14 root-knot nematode (RKN) (Meloidogyne incognita) resistance QTLs provides insights into the regulation of the RKN resistance response in Upland cotton...

    Science.gov (United States)

    High levels of resistance to root-knot nematode (RKN) (Meloidogyne incognita) in Upland cotton (Gossypium hirsutum) is mediated by two major quantitative trait loci (QTL) located on chromosomes 11 and 14. We had previously determined that MIC-3 expression played a direct role in suppressing RKN egg...

  18. The extent of anthelmintic Resistance on Nematodes in communally grazed sheep and goats in a Semi-Arid area of North-west Province (RSA) / Tebogo Stanely Ramotshwane

    OpenAIRE

    Ramotshwane, Tebogo Stanely

    2011-01-01

    A survey was conducted to investigate the occurrence of anthelmintic resistance of nematodes in communally grazed sheep and goat herds in the Zeerust area of the North-West Province, Republic of South Africa. The fecal egg count reduction test (FECR%) tests were used to assess the sheep and goat small holder farmers. Efficacy of albendazole, ivermectin and closantel was done on both the treatment and control animals. Anthelmintic efficacy of 80% was considered a threshold for ...

  19. A real-time PCR approach to identify anthelmintic-resistant nematodes in sheep farms.

    Science.gov (United States)

    Milhes, M; Guillerm, M; Robin, M; Eichstadt, M; Roy, C; Grisez, C; Prévot, F; Liénard, E; Bouhsira, E; Franc, M; Jacquiet, P

    2017-03-01

    Resistance to fenbendazole, ivermectin, and moxidectin was explored by a fecal egg count reduction test in four meat sheep flocks in southwestern France where anthelmintic resistance was suspected. The FECR test results of the present study confirmed the presence of benzimidazole resistance in three out of the four farms and the presence of ivermectin resistance in one flock. In addition, a suspicion of moxidectin resistance was shown in this latter farm. Both conventional morphological and molecular identifications were performed on larval cultures before and after the treatment in the studied farms. A high positive correlation was found between the number of larvae counted under binocular microscope and the number of larvae estimated by the qPCR analysis (R 2  = 0.88) and a high Cohen's Kappa value (0.91) in the detection of strongylid larvae in larval cultures. According to qPCR results, Trichostrongylus species demonstrated high levels of BZ resistance and Teladorsagia circumcincta was involved in the IVM resistance in one farm. The molecular procedures used in this study have the potential to be beneficial for anthelmintic resistance surveillance in sheep industry.

  20. Resistance to benzimidazoles and levamisole in nematode parasites of sheep in Nyandarua district of Kenya

    DEFF Research Database (Denmark)

    Maingi, N.; Bjørn, H.; Gichohi, V.M.

    1998-01-01

    The occurrence of anthelmintic resistance on 25 sheep farms in the Nyandarua District of Kenya was investigated, using the faecal egg count reduction test (FECRT), the egg hatch assay (EHA) and a larval development assay (LDA). In the FECRT, resistance to both benzimidazoles (BZs) and levamisole...

  1. The suppression of tomato defence response genes upon potato cyst nematode infection indicates a key regulatory role of miRNAs.

    Science.gov (United States)

    Święcicka, Magdalena; Skowron, Waldemar; Cieszyński, Piotr; Dąbrowska-Bronk, Joanna; Matuszkiewicz, Mateusz; Filipecki, Marcin; Koter, Marek Daniel

    2017-04-01

    Potato cyst nematode Globodera rostochiensis is an obligate parasite of solanaceous plants, triggering metabolic and morphological changes in roots which may result in substantial crop yield losses. Previously, we used the cDNA-AFLP to study the transcriptional dynamics in nematode infected tomato roots. Now, we present the rescreening of already published, upregulated transcript-derived fragment dataset using the most current tomato transcriptome sequences. Our reanalysis allowed to add 54 novel genes to 135, already found as upregulated in tomato roots upon G. rostochiensis infection (in total - 189). We also created completely new catalogue of downregulated sequences leading to the discovery of 76 novel genes. Functional classification of candidates showed that the 'wound, stress and defence response' category was enriched in the downregulated genes. We confirmed the transcriptional dynamics of six genes by qRT-PCR. To place our results in a broader context, we compared the tomato data with Arabidopsis thaliana, revealing similar proportions of upregulated and downregulated genes as well as similar enrichment of defence related transcripts in the downregulated group. Since transcript suppression is quite common in plant-nematode interactions, we assessed the possibility of miRNA-mediated inverse correlation on several tomato sequences belonging to NB-LRR and receptor-like kinase families. The qRT-PCR of miRNAs and putative target transcripts showed an opposite expression pattern in 9 cases. These results together with in silico analyses of potential miRNA targeting to the full repertoire of tomato R-genes show that miRNA mediated gene suppression may be a key regulatory mechanism during nematode parasitism. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Transcriptomic Analysis and the Expression of Disease-Resistant Genes in Oryza meyeriana under Native Condition.

    Directory of Open Access Journals (Sweden)

    Bin He

    Full Text Available Oryza meyeriana (O. meyeriana, with a GG genome type (2n = 24, accumulated plentiful excellent characteristics with respect to resistance to many diseases such as rice shade and blast, even immunity to bacterial blight. It is very important to know if the diseases-resistant genes exist and express in this wild rice under native conditions. However, limited genomic or transcriptomic data of O. meyeriana are currently available. In this study, we present the first comprehensive characterization of the O. meyeriana transcriptome using RNA-seq and obtained 185,323 contigs with an average length of 1,692 bp and an N50 of 2,391 bp. Through differential expression analysis, it was found that there were most tissue-specifically expressed genes in roots, and next to stems and leaves. By similarity search against protein databases, 146,450 had at least a significant alignment to existed gene models. Comparison with the Oryza sativa (japonica-type Nipponbare and indica-type 93-11 genomes revealed that 13% of the O. meyeriana contigs had not been detected in O. sativa. Many diseases-resistant genes, such as bacterial blight resistant, blast resistant, rust resistant, fusarium resistant, cyst nematode resistant and downy mildew gene, were mined from the transcriptomic database. There are two kinds of rice bacterial blight-resistant genes (Xa1 and Xa26 differentially or specifically expressed in O. meyeriana. The 4 Xa1 contigs were all only expressed in root, while three of Xa26 contigs have the highest expression level in leaves, two of Xa26 contigs have the highest expression profile in stems and one of Xa26 contigs was expressed dominantly in roots. The transcriptomic database of O. meyeriana has been constructed and many diseases-resistant genes were found to express under native condition, which provides a foundation for future discovery of a number of novel genes and provides a basis for studying the molecular mechanisms associated with disease

  3. Screening edible ginger and turmeric cultivars for resistance to root-knot nematodes

    Science.gov (United States)

    Twenty-two edible ginger and turmeric cultivars were screened for resistance or tolerance to Meloidogyne incognita. Plants were raised in 66 L grow bags in greenhouses in Hawaii according to established practices for producing bacterial wilt-free ginger. Three months after planting, each grow bag ...

  4. The prevalence of anthelmintic resistance in nematode parasites of sheep in southern Latin America: Brazil.

    Science.gov (United States)

    Echevarria, F; Borba, M F; Pinheiro, A C; Waller, P J; Hansen, J W

    1996-04-01

    This survey was conducted in the southern Brazilian state of Rio Grande do Sul and involved 182 farms located in 26 counties. In addition to the three major broad-spectrum anthelmintic groups (viz. benzimidazole, levamisole and ivermectin) the combination benzimidazole and levamisole and the H. contortus specific anthelmintic, closantel, were tested by the faecal egg count reduction method for the prevalence of anthelmintic resistance. Resistance was found to be 90%, 84%, 13%, 73% and 20%, respectively. This is a crisis situation. Immediate, drastic action needs to be implemented, otherwise the sheep industry in this region (approx. 10 million head) will soon face a lack of any effective anthelmintics with the inevitable consequences of major restructuring or abandonment.

  5. Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil

    Directory of Open Access Journals (Sweden)

    Jordana Andrioli Salgado

    2016-03-01

    Full Text Available Abstract Frequent and inappropriate use of all classes of antiparasitic drugs in small ruminants has led to failures in their effectiveness, culminating in a global problem of anthelmintic resistance. Brazil stands out as one of the world’s leaders in publications about anthelmintic resistance, and for having the most numerous reports of this resistance in small ruminants in the Americas. These studies have involved mainly the fecal egg count reduction test (FECRT and its correlation with field management practices. In vivoeffectiveness testing is conducted in areas where livestock is of greater economic significance, e.g., in the South (sheep and Northeast (goats, or is important for research and economic centers, such as the Southeast (sheep. The most widely studied species is sheep, for which the widest range of drugs is also evaluated. Despite significant advances achieved in molecular research, laboratory analyses should include knowledge about the reality in the field so that they can become feasible for the producer. Moreover, molecular studies can be underpinned by the analysis of field studies, such as the maintenance of antiparasitic effectiveness over time and the mechanisms involved in this process.

  6. Endogenous cellulases in animals: Isolation of β-1,4-endoglucanase genes from two species of plant-parasitic cyst nematodes

    Science.gov (United States)

    Smant, Geert; Stokkermans, Jack P. W. G.; Yan, Yitang; de Boer, Jan M.; Baum, Thomas J.; Wang, Xiaohong; Hussey, Richard S.; Gommers, Fred J.; Henrissat, Bernard; Davis, Eric L.; Helder, Johannes; Schots, Arjen; Bakker, Jaap

    1998-01-01

    β-1,4-Endoglucanases (EGases, EC 3.2.1.4) degrade polysaccharides possessing β-1,4-glucan backbones such as cellulose and xyloglucan and have been found among extremely variegated taxonomic groups. Although many animal species depend on cellulose as their main energy source, most omnivores and herbivores are unable to produce EGases endogenously. So far, all previously identified EGase genes involved in the digestive system of animals originate from symbiotic microorganisms. Here we report on the synthesis of EGases in the esophageal glands of the cyst nematodes Globodera rostochiensis and Heterodera glycines. From each of the nematode species, two cDNAs were characterized and hydrophobic cluster analysis revealed that the four catalytic domains belong to family 5 of the glycosyl hydrolases (EC 3.2.1, 3.2.2, and 3.2.3). These domains show 37–44% overall amino acid identity with EGases from the bacteria Erwinia chrysanthemi, Clostridium acetobutylicum, and Bacillus subtilis. One EGase with a bacterial type of cellulose-binding domain was identified for each nematode species. The leucine-rich hydrophobic core of the signal peptide and the presence of a polyadenylated 3′ end precluded the EGases from being of bacterial origin. Cyst nematodes are obligatory plant parasites and the identified EGases presumably facilitate the intracellular migration through plant roots by partial cell wall degradation. PMID:9560201

  7. Genetic regulation of parasite infection: empirical evidence of the functional significance of an IL4 gene SNP on nematode infections in wild primates

    Directory of Open Access Journals (Sweden)

    Kappeler Peter M

    2011-04-01

    Full Text Available Abstract Background Susceptibility to parasite infection affects fitness-related processes, such as mate choice and survival, yet its genetic regulation remains poorly understood. Interleukin-4 (IL4 plays a central role in the humoral immune defence against nematode parasite infections, inducing IgE switch and regulation of worm expulsion from the intestines. The evolutionary and functional significance of single nucleotide polymorphisms (SNPs in IL4-genes is known, yet empirical information on the effect of IL4 SNPs on gastro-intestinal infections is lacking. Using samples from a population of wild red-fronted lemurs (Eulemur fulvus rufus, Primates: Lemuridae, from western Madagascar, we explored the association of IL4-gene promoter polymorphisms with nematode infections and investigated a possible functional role of the IL4 polymorphism on male reproductive success. Results Using sequence analyses of lemur DNA we detected a new SNP in the IL4 gene promoter area. Carriers of the genotype T/T showed higher nematode infection intensities than individuals of genotypes C/T and C/C. Genetic population analyses using data from more than 10 years, suggested higher reproductive success of T/T males than expected. Conclusions Our results suggest a regulatory effect of an IL4 gene promoter polymorphism on the intensity of parasite infections in a natural population of red-fronted lemurs, with a seemingly disadvantageous genotype represented in low frequencies. Long-term population analyses, however, point in the direction of a negative frequency-dependent association, giving a fitness advantage to the rare genotype. Due to low frequencies of the genotype in question conclusive evidence of a functional role of IL4 polymorphism cannot be drawn here; still, we suggest the use of IL4 polymorphism as a new molecular tool for quick assessment of individual genetic constitution with regard to nematode infection intensities, contributing to a better

  8. Nematode cholinergic pharmacology

    International Nuclear Information System (INIS)

    Segerberg, M.A.

    1989-01-01

    Nematode acetylcholine (ACh) receptors were characterized using both biochemical and electrophysiological techniques, including: (1) receptor binding studies in crude homogenates of the free-living nematode Caenorhabditis elegans and the parasitic nematode Ascaris lumbricoides with the high-affinity probe [ 3 H]N-methylscopolamine ([ 3 H]NMS) which binds to muscarinic receptors in many vertebrate and invertebrate tissues (2) measurement of depolarization and contraction induced by a variety of cholinergic agents, including N-methylscopolamine (NMS), in an innervated dorsal muscle strip preparation of Ascaris; (3) examination of the antagonistic actions of d-tubocurarine (dTC) and NMS at dorsal neuromuscular junction; (4) measurement of input resistance changes in Ascaris commissural motorneurons induced by ACh, dTC, NMS, pilocarpine and other cholinergic drugs

  9. Organization of a resistance gene cluster linked to rhizomania resistance in sugar beet

    Science.gov (United States)

    Genetic resistance to rhizomania has been in use for over 40 years. Characterization of the molecular basis for susceptibility and resistance has proved challenging. Nucleotide-binding leucine-rich-repeat-containing (NB-LRR) genes have been implicated in numerous gene-for-gene resistance interaction...

  10. Shifting from priming of salicylic acid- to jasmonic acid-regulated defences by Trichoderma protects tomato against the root knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Martínez-Medina, Ainhoa; Fernandez, Ivan; Lok, Gerrit B; Pozo, María J; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-02-01

    Beneficial root endophytes such as Trichoderma spp. can reduce infections by parasitic nematodes through triggering host defences. Little is currently known about the complex hormone signalling underlying the induction of resistance. In this study, we investigated whether Trichoderma modulates the hormone signalling network in the host to induce resistance to nematodes. We investigated the role and the timing of the jasmonic acid (JA)- and salicylic acid (SA)-regulated defensive pathways in Trichoderma-induced resistance to the root knot nematode Meloidogyne incognita. A split-root system of tomato (Solanum lycopersicum) was used to study local and systemic induced defences by analysing nematode performance, defence gene expression, responsiveness to exogenous hormone application, and dependence on SA and JA signalling of Trichoderma-induced resistance. Root colonization by Trichoderma impeded nematode performance both locally and systemically at multiple stages of the parasitism, that is, invasion, galling and reproduction. First, Trichoderma primed SA-regulated defences, which limited nematode root invasion. Then, Trichoderma enhanced JA-regulated defences, thereby antagonizing the deregulation of JA-dependent immunity by the nematodes, which compromised galling and fecundity. Our results show that Trichoderma primes SA- and JA-dependent defences in roots, and that the priming of responsiveness to these hormones upon nematode attack is plastic and adaptive to the parasitism stage. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  11. The Pochonia chlamydosporia serine protease gene vcp1 is subject to regulation by carbon, nitrogen and pH: implications for nematode biocontrol.

    Science.gov (United States)

    Ward, Elaine; Kerry, Brian R; Manzanilla-López, Rosa H; Mutua, Gerald; Devonshire, Jean; Kimenju, John; Hirsch, Penny R

    2012-01-01

    The alkaline serine protease VCP1 of the fungus Pochonia chlamydosporia belongs to a family of subtilisin-like enzymes that are involved in infection of nematode and insect hosts. It is involved early in the infection process, removing the outer proteinaceous vitelline membrane of nematode eggs. Little is known about the regulation of this gene, even though an understanding of how nutrients and other factors affect its expression is critical for ensuring its efficacy as a biocontrol agent. This paper provides new information on the regulation of vcp1 expression. Sequence analysis of the upstream regulatory region of this gene in 30 isolates revealed that it was highly conserved and contained sequence motifs characteristic of genes that are subject to carbon, nitrogen and pH-regulation. Expression studies, monitoring enzyme activity and mRNA, confirmed that these factors affect VCP1 production. As expected, glucose reduced VCP1 expression and for a few hours so did ammonium chloride. Surprisingly, however, by 24 h VCP1 levels were increased in the presence of ammonium chloride for most isolates. Ambient pH also regulated VCP1 expression, with most isolates producing more VCP1 under alkaline conditions. There were some differences in the response of one isolate with a distinctive upstream sequence including a variant regulatory-motif profile. Cryo-scanning electron microscopy studies indicated that the presence of nematode eggs stimulates VCP1 production by P. chlamydosporia, but only where the two are in close contact. Overall, the results indicate that readily-metabolisable carbon sources and unfavourable pH in the rhizosphere/egg-mass environment may compromise nematode parasitism by P. chlamydosporia. However, contrary to previous indications using other nematophagous and entomopathogenic fungi, ammonium nitrate (e.g. from fertilizers) may enhance biocontrol potential in some circumstances.

  12. The Pochonia chlamydosporia serine protease gene vcp1 is subject to regulation by carbon, nitrogen and pH: implications for nematode biocontrol.

    Directory of Open Access Journals (Sweden)

    Elaine Ward

    Full Text Available The alkaline serine protease VCP1 of the fungus Pochonia chlamydosporia belongs to a family of subtilisin-like enzymes that are involved in infection of nematode and insect hosts. It is involved early in the infection process, removing the outer proteinaceous vitelline membrane of nematode eggs. Little is known about the regulation of this gene, even though an understanding of how nutrients and other factors affect its expression is critical for ensuring its efficacy as a biocontrol agent. This paper provides new information on the regulation of vcp1 expression. Sequence analysis of the upstream regulatory region of this gene in 30 isolates revealed that it was highly conserved and contained sequence motifs characteristic of genes that are subject to carbon, nitrogen and pH-regulation. Expression studies, monitoring enzyme activity and mRNA, confirmed that these factors affect VCP1 production. As expected, glucose reduced VCP1 expression and for a few hours so did ammonium chloride. Surprisingly, however, by 24 h VCP1 levels were increased in the presence of ammonium chloride for most isolates. Ambient pH also regulated VCP1 expression, with most isolates producing more VCP1 under alkaline conditions. There were some differences in the response of one isolate with a distinctive upstream sequence including a variant regulatory-motif profile. Cryo-scanning electron microscopy studies indicated that the presence of nematode eggs stimulates VCP1 production by P. chlamydosporia, but only where the two are in close contact. Overall, the results indicate that readily-metabolisable carbon sources and unfavourable pH in the rhizosphere/egg-mass environment may compromise nematode parasitism by P. chlamydosporia. However, contrary to previous indications using other nematophagous and entomopathogenic fungi, ammonium nitrate (e.g. from fertilizers may enhance biocontrol potential in some circumstances.

  13. Isolation of DNA markers linked to a beet cyst nematode resistamce locus in Beta patellaris and Beta procumbens

    NARCIS (Netherlands)

    Salentijn, E.M.J.; Sandal, N.N.; Lange, W.; Bock, de T.S.M.; Krens, F.A.; Marcker, K.A.; Stiekema, W.J.

    1992-01-01

    In cultivated beet no useful level of resistance of the beet cyst nematode (BCN) Heterodera schachtii Schm. has been found, unlike the situation in wild species of the section Procumbentes. Stable introgression of resistance genes from the wild species into Beta vulgaris has not been achieved, but

  14. Structural and functional characterization of a novel gene, Hc-daf-22, from the strongylid nematode Haemonchus contortus.

    Science.gov (United States)

    Guo, Xiaolu; Zhang, Hongli; Zheng, Xiuping; Zhou, Qianjin; Yang, Yi; Chen, Xueqiu; Du, Aifang

    2016-07-29

    The strongylid nematode Haemonchus contortus is a parasite of major concern for modern livestock husbandry because hostile environmental conditions may induce diapause in the early fourth-stage larvae. A new gene Hc-daf-22 was identified which is the homologue of Ce-daf-22 and human SCPx. Genome walking and RACE were performed to obtain the whole cDNA and genomic sequence of this gene. Using qRT-PCR with all developmental stages as templates to explore the transcription level and micro-injection was applied to confirm the promoter activity of the 5'-flanking region. Overexpression, rescue and RNA interference experiments were performed in N2, daf-22 mutant (ok 693) strains of C. elegans to study the gene function of Hc-daf-22. The full length gene of Hc-daf-22 (6,939 bp) contained 16 exons separated by 15 introns, and encoded a cDNA of 1,602 bp (533 amino acids, estimated at about 59.3 kDa) with a peak in L3 and L4 in transcriptional level. The Hc-DAF-22 protein was consisted of a 3-oxoacyl-CoA thiolase domain and a SCP2 domain and evolutionarily conserved. The 1,548 bp fragment upstream of the 5'-flanking region was confirmed to have promoter activity compared with 5'-flanking region of Ce-daf-22. The rescue experiment by micro-injection of daf-22 (ok693) mutant strain showed significant increase in body size and brood size in the rescued worms with significantly reduced or completely absent fat granules confirmed by Oil red O staining, indicating that Hc-daf-22 could partially rescue the function of Ce-daf-22. Furthermore, RNAi with Hc-daf-22 could partially silence the endogenous Ce-daf-22 in N2 worms and mimic the phenotype of daf-22 (ok693) mutants. The gene Hc-daf-22 was isolated and its function identified using C. elegans as a model organism. Our results indicate that Hc-daf-22 shared similar characteristics and function with Ce-daf-22 and may play an important role in peroxisomal β-oxidation and the development in H. contortus.

  15. RNAi effector diversity in nematodes.

    Directory of Open Access Journals (Sweden)

    Johnathan J Dalzell

    2011-06-01

    Full Text Available While RNA interference (RNAi has been deployed to facilitate gene function studies in diverse helminths, parasitic nematodes appear variably susceptible. To test if this is due to inter-species differences in RNAi effector complements, we performed a primary sequence similarity survey for orthologs of 77 Caenorhabditis elegans RNAi pathway proteins in 13 nematode species for which genomic or transcriptomic datasets were available, with all outputs subjected to domain-structure verification. Our dataset spanned transcriptomes of Ancylostoma caninum and Oesophagostomum dentatum, and genomes of Trichinella spiralis, Ascaris suum, Brugia malayi, Haemonchus contortus, Meloidogyne hapla, Meloidogyne incognita and Pristionchus pacificus, as well as the Caenorhabditis species C. brenneri, C. briggsae, C. japonica and C. remanei, and revealed that: (i Most of the C. elegans proteins responsible for uptake and spread of exogenously applied double stranded (dsRNA are absent from parasitic species, including RNAi-competent plant-nematodes; (ii The Argonautes (AGOs responsible for gene expression regulation in C. elegans are broadly conserved, unlike those recruited during the induction of RNAi by exogenous dsRNA; (iii Secondary Argonautes (SAGOs are poorly conserved, and the nuclear AGO NRDE-3 was not identified in any parasite; (iv All five Caenorhabditis spp. possess an expanded RNAi effector repertoire relative to the parasitic nematodes, consistent with the propensity for gene loss in nematode parasites; (v In spite of the quantitative differences in RNAi effector complements across nematode species, all displayed qualitatively similar coverage of functional protein groups. In summary, we could not identify RNAi effector deficiencies that associate with reduced susceptibility in parasitic nematodes. Indeed, similarities in the RNAi effector complements of RNAi refractory and competent nematode parasites support the broad applicability of this research

  16. Differential Change Patterns of Main Antimicrobial Peptide Genes During Infection of Entomopathogenic Nematodes and Their Symbiotic Bacteria.

    Science.gov (United States)

    Darsouei, Reyhaneh; Karimi, Javad; Ghadamyari, Mohammad; Hosseini, Mojtaba

    2017-08-01

    The expression of antimicrobial peptides (AMPs) as the main humoral defense reactions of insects during infection by entomopathogenic nematodes (EPNs) and their symbiont is addressed herein. Three AMPs, attacin, cecropin, and spodoptericin, were evaluated in the fifth instar larvae of Spodoptera exigua Hübner (beet armyworm) when challenged with Steinernema carpocapsae or Heterorhabditis bacteriophora. The results indicated that attacin was expressed to a greater extent than either cecropin or spodoptericin. While spodoptericin was expressed to a much lesser extent, this AMP was induced against Gram-positive bacteria, and thus not expressed after penetration of Xenorhabdus nematophila and Photorhabdus luminescens. Attacin and cecropin in the larvae treated with S. carpocapsae at 8 hr post-injection (PI) attained the maximum expression levels and were 138.42-fold and 65.84-fold greater than those of larvae infected with H. bacteriophora, respectively. Generally, the ability of H. bacteriophora to suppress attacin, cecropin, and spodoptericin was greater than that of S. carpocapsae. According to the results, the expression of AMPs by Sp. exigua larvae against S. carpocapsae was determined in the 4 statuses of monoxenic nematode, axenic nematode, live symbiotic bacterium, and dead symbiotic bacterium. The expression of attacin in larvae treated with a monoxenic nematode and live bacterium at 8 and 2 hr PI, respectively, were increased to the maximum amount. Live X. nematophila was the strongest agent for the suppression of attacin. The expression of cecropin against monoxenic nematodes and live symbiotic bacteria at 8 and 4 hr PI, respectively, reached the maximum amount while the expression levels of attacin and cecropin for axenic nematodes were lesser and stable. The results highlighted that the ability of P. luminescens in AMPs suppression was much more than X. nematophila. The results also showed that the effect of symbiotic bacterium in suppressing attacin and

  17. RNA-Seq Based Identification of Candidate Parasitism Genes of Cereal Cyst Nematode (Heterodera avenae during Incompatible Infection to Aegilops variabilis.

    Directory of Open Access Journals (Sweden)

    Minghui Zheng

    Full Text Available One of the reasons for the progressive yield decline observed in cereals production is the rapid build-up of populations of the cereal cyst nematode (CCN, Heterodera avenae. These nematodes secrete so-call effectors into their host plant to suppress the plant defense responses, alter plant signaling pathways and then induce the formation of syncytium after infection. However, little is known about its molecular mechanism and parasitism during incompatible infection. To gain insight into its repertoire of parasitism genes, we investigated the transcriptome of the early parasitic second-stage (30 hours, 3 days and 9 days post infection juveniles of the CCN as well as the CCN infected tissue of the host Aegilops variabilis by Illumina sequencing. Among all assembled unigenes, 681 putative genes of parasitic nematode were found, in which 56 putative effectors were identified, including novel pioneer genes and genes corresponding to previously reported effectors. All the 681 CCN unigenes were mapped to 229 GO terms and 200 KEGG pathways, including growth, development and several stimulus-related signaling pathways. Sixteen clusters were involved in the CCN unigene expression atlas at the early stages during infection process, and three of which were significantly gene-enriched. Besides, the protein-protein interaction network analysis revealed 35 node unigenes which may play an important role in the plant-CCN interaction. Moreover, in a comparison of differentially expressed genes between the pre-parasitic juveniles and the early parasitic juveniles, we found that hydrolase activity was up-regulated in pre J2s whereas binding activity was upregulated in infective J2s. RT-qPCR analysis on some selected genes showed detectable expression, indicating possible secretion of the proteins and putative role in infection. This study provided better insights into the incompatible interaction between H. avenae and the host plant Ae. varabilis. Moreover, RNAi

  18. Molecular characterization and functional analysis of ubiquitin extension genes from the potato cyst nematode Globodera rostochiensis

    Science.gov (United States)

    Ubiquitin is a highly conserved 76-amino acid protein found in every eukaryotic cell. It has been proposed that ubiquitin has many cellular functions including DNA repair, transcription regulation, regulation of cell cycle and apoptosis. We identified two ubiquitin extension genes (Gr-Ubi1 and Gr-Ub...

  19. Synteny of orthologous genes conserved in human, mouse, snake, Drosophila, nematode, and fission yeast

    Czech Academy of Sciences Publication Activity Database

    Trachtulec, Zdeněk; Forejt, Jiří

    2001-01-01

    Roč. 12, č. 3 (2001), s. 227-231 ISSN 0938-8990 Institutional research plan: CEZ:AV0Z5052915 Keywords : synteny of orthologous genes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.318, year: 2001

  20. Role of Horizontal Gene Transfer in the Evolution of Plant Parasitism Among Nematodes

    NARCIS (Netherlands)

    Mitreva, M.; Smant, G.; Helder, J.

    2009-01-01

    Horizontal gene transfer (HGT) implies the non-sexual exchange of genetic material between species ¿ in some cases even across kingdoms. Although common among Bacteria and Archaea, HGTs from pro- to eukaryotes and between eukaryotes were thought to be extremely rare. Recent studies on intracellular

  1. Molecular aspects of cyst nematodes.

    Science.gov (United States)

    Lilley, Catherine J; Atkinson, Howard J; Urwin, Peter E

    2005-11-01

    SUMMARY Taxonomy: Superkingdom Eukaryota; kingdom Metazoa; phylum Nematoda; class Chromadorea; order Tylenchida; suborder Tylenchina; superfamily Tylenchoidea; family Heteroderidae; subfamily Heteroderinae; main genera Heterodera and Globodera. Cyst nematodes comprise approximately 100 known species in six genera. They are pathogens of temperate, subtropical and tropical plant species and the host range of many species is narrow. The most economically important species are within the Globodera and Heterodera genera. Globodera pallida and G. rostochiensis are important pathogens of potato crops. There are many economic species in the Heterodera genus, including Heterodera glycines (soybean cyst nematode), H. avenae (cereal cyst nematode) and H. schachtii (sugar beet cyst nematode), the last of which attacks a range of Chenopodiaceae and Cruciferae, including Arabidopsis thaliana. Disease symptoms: Field symptoms of severe cyst nematode infection are often stunting, wilting and chlorosis, but considerable yield loss can occur without obvious symptoms. The only unique indicator of cyst nematode infection is the presence of adult female nematodes attached to host roots after several weeks of parasitism. Disease control: This is usually achieved by using integrated pest management involving cultural practices such as crop rotation, resistant cultivars if available and chemical control when economically justified.

  2. Functional comparison of the nematode Hox gene lin-39 in C. elegans and P. pacificus reveals evolutionary conservation of protein function despite divergence of primary sequences.

    Science.gov (United States)

    Grandien, K; Sommer, R J

    2001-08-15

    Hox transcription factors have been implicated in playing a central role in the evolution of animal morphology. Many studies indicate the evolutionary importance of regulatory changes in Hox genes, but little is known about the role of functional changes in Hox proteins. In the nematodes Pristionchus pacificus and Caenorhabditis elegans, developmental processes can be compared at the cellular, genetic, and molecular levels and differences in gene function can be identified. The Hox gene lin-39 is involved in the regulation of nematode vulva development. Comparison of known lin-39 mutations in P. pacificus and C. elegans revealed both conservation and changes of gene function. Here, we study evolutionary changes of lin-39 function using hybrid transgenes and site-directed mutagenesis in an in vivo assay using C. elegans lin-39 mutants. Our data show that despite the functional differences of LIN-39 between the two species, Ppa-LIN-39, when driven by Cel-lin-39 regulatory elements, can functionally replace Cel-lin-39. Furthermore, we show that the MAPK docking and phosphorylation motifs unique for Cel-LIN-39 are dispensable for Cel-lin-39 function. Therefore, the evolution of lin-39 function is driven by changes in regulatory elements rather than changes in the protein itself.

  3. Candidate gene approach for parasite resistance in sheep--variation in immune pathway genes and association with fecal egg count.

    Directory of Open Access Journals (Sweden)

    Kathiravan Periasamy

    Full Text Available Sheep chromosome 3 (Oar3 has the largest number of QTLs reported to be significantly associated with resistance to gastro-intestinal nematodes. This study aimed to identify single nucleotide polymorphisms (SNPs within candidate genes located in sheep chromosome 3 as well as genes involved in major immune pathways. A total of 41 SNPs were identified across 38 candidate genes in a panel of unrelated sheep and genotyped in 713 animals belonging to 22 breeds across Asia, Europe and South America. The variations and evolution of immune pathway genes were assessed in sheep populations across these macro-environmental regions that significantly differ in the diversity and load of pathogens. The mean minor allele frequency (MAF did not vary between Asian and European sheep reflecting the absence of ascertainment bias. Phylogenetic analysis revealed two major clusters with most of South Asian, South East Asian and South West Asian breeds clustering together while European and South American sheep breeds clustered together distinctly. Analysis of molecular variance revealed strong phylogeographic structure at loci located in immune pathway genes, unlike microsatellite and genome wide SNP markers. To understand the influence of natural selection processes, SNP loci located in chromosome 3 were utilized to reconstruct haplotypes, the diversity of which showed significant deviations from selective neutrality. Reduced Median network of reconstructed haplotypes showed balancing selection in force at these loci. Preliminary association of SNP genotypes with phenotypes recorded 42 days post challenge revealed significant differences (P<0.05 in fecal egg count, body weight change and packed cell volume at two, four and six SNP loci respectively. In conclusion, the present study reports strong phylogeographic structure and balancing selection operating at SNP loci located within immune pathway genes. Further, SNP loci identified in the study were found to have

  4. Induction of SA-signaling pathway and ethylene biosynthesis in Trichoderma harzianum-treated tomato plants after infection of the root-knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Leonetti, Paola; Zonno, Maria Chiara; Molinari, Sergio; Altomare, Claudio

    2017-04-01

    Salicylic acid-signaling pathway and ethylene biosynthesis were induced in tomato treated with Trichoderma harzianum when infected by root-knot nematodes and limited the infection by activation of SAR and ethylene production. Soil pre-treatment with Trichoderma harzianum (Th) strains ITEM 908 (T908) and T908-5 decreased susceptibility of tomato to Meloidogyne incognita, as assessed by restriction in nematode reproduction and development. The effect of T. harzianum treatments on plant defense was detected by monitoring the expression of the genes PR-1/PR-5 and JERF3/ACO, markers of the SA- and JA/ET-dependent signaling pathways, respectively. The compatible nematode-plant interaction in absence of fungi caused a marked suppression of PR-1, PR-5, and ACO gene expressions, either locally or systemically, whilst expression of JERF3 gene resulted unaffected. Conversely, when plants were pre-treated with Th-strains, over-expression of PR-1, PR-5, and ACO genes was observed in roots 5 days after nematode inoculation. JERF3 gene expression did not change in Th-colonized plants challenged with nematodes. In the absence of nematodes, Trichoderma-root interaction was characterized by the inhibition of both SA-dependent signaling pathway and ET biosynthesis, and, in the case of PR-1 and ACO genes, this inhibition was systemic. JERF3 gene expression was systemically restricted only at the very early stages of plant-fungi interaction. Data presented indicate that Th-colonization primed roots for Systemic Acquired Resistance (SAR) against root-knot nematodes and reacted to nematode infection more efficiently than untreated plants. Such a response probably involves also activation of ET production, through an augmented transcription of the ACO gene, which encodes for the enzyme catalyzing the last step of ET biosynthesis. JA signaling and Induced Systemic Resistance (ISR) do not seem to be involved in the biocontrol action of the tested Th-strains against RKNs.

  5. P-glycoprotein-9 and macrocyclic lactone resistance status in selected strains of the ovine gastrointestinal nematode, Teladorsagia circumcincta.

    Science.gov (United States)

    Turnbull, Frank; Jonsson, Nicholas N; Kenyon, Fiona; Skuce, Philip J; Bisset, Stewart A

    2018-04-01

    The Teladorsagia circumcincta P-glycoprotein-9 (Tci-pgp-9) gene has previously been implicated in multiple-anthelmintic resistance in this parasite. Here we further characterise genetic diversity in Tci-pgp-9 and its possible role in ivermectin (IVM) and multi-drug resistance using two UK field isolates of T. circumcincta, one susceptible to anthelmintics (MTci2) and the other resistant to most available anthelmintics including IVM (MTci5). A comparison of full-length Tci-pgp-9 cDNA transcripts from the MTci2 and MTci5 isolates (∼3.8 kb in both cases) indicated that they shared 95.6% and 99.5% identity at the nucleotide and amino acid levels, respectively. Nine non-synonymous SNPs were found in the MTci5 sequences relative to their MTci2 counterparts. Twelve genomic sequence variants of the first internucleotide binding domain of Tci-pgp-9 were identified and up to 10 of these were present in some individual worms, strongly supporting previous evidence that amplification of this gene has occurred in T. circumcincta. On average, fewer distinct sequence variants of Tci-pgp-9 were present in individual worms of the MTci5 isolate than in those of the MTci2 isolate. A further reduction in the number of sequence variants was observed in individuals derived from an IVM-treated sub-population of MTci5. These findings suggest that Tci-pgp-9 was under purifying selection in the face of IVM treatment in T. circumcincta, with some sequence variants being selected against. Copyright © 2018. Published by Elsevier Ltd.

  6. Molecular detection of disease resistance genes to powdery mildew ...

    African Journals Online (AJOL)

    A study was conducted to detect the presence of disease resistance genes to infection of wheat powdery mildew (Blumeria graminis f. sp. tritici) in selected wheat cultivars from China using molecular markers. Genomic DNA of sixty cultivars was extracted and tested for the presence of selected prominent resistance genes to ...

  7. Genome scanning for identification of resistance gene analogs (RGAs)

    African Journals Online (AJOL)

    Disease resistance in plants is a desirable economic trait. Many disease resistance genes from various plants have been cloned so far. The gene products of some of these can be distinguished by the presence of an N terminal nucleotide binding site and a C-terminal stretch of leucine-rich repeats. Oligonucleotides already ...

  8. Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil

    DEFF Research Database (Denmark)

    Peirano, G.; Agersø, Yvonne; Aarestrup, Frank Møller

    2005-01-01

    Objectives: To determine the occurrence of class 1 and 2 integrons and antimicrobial resistance genes among sulphonamide-resistant Shigella strains isolated in Brazil during 1999-2003. Methods: Sixty-two Shigella (Shigella flexneri, n = 47 and Shigella sonnei, n = 15) were tested against 21...... antimicrobial agents. The presence of integrons classes 1 and 2 and antimicrobial resistance genes was investigated by PCR using specific primers. Results: A total of eight antimicrobial resistance profiles were identified, with the profile of resistance to sulfamethoxazole, trimethoprim, spectinomycin...... of 2214 bp harbouring a gene cassette array conferring resistance to trimethoprim, streptothricin and spectinomycin/streptomycin. The genes coding for resistance to chloramphenicol (catA1), tetracycline [tet(A) and tet(B)] and ampicillin (bla(OXA) and bla(TEM)), were detected in resistant strains...

  9. Toxic effects of di(2-ethylhexyl)phthalate on mortality, growth, reproduction and stress-related gene expression in the soil nematode Caenorhabditis elegans.

    Science.gov (United States)

    Roh, Ji-Yeon; Jung, In-Ho; Lee, Jai-Young; Choi, Jinhee

    2007-07-31

    In this study, di(2-ethylhexyl)phthalate (DEHP) toxicities to Caenorhabditis elegans were investigated using multiple toxic endpoints, such as mortality, growth, reproduction and stress-related gene expression, focusing on the identification of chemical-induced gene expression as a sensitive biomarker for DEHP monitoring. The possible use of C. elegans as a sentinel organism in the monitoring of soil ecosystem health was also tested by conducting the experiment on the exposure of nematode to field soil. Twenty-four-hour median lethal concentration (LC50) data suggest that DEHP has a relatively high potential of acute toxicity to C. elegans. Decreases in body length and egg number per worm observed after 24h of DEHP exposure may induce long-term alteration in the growth and reproduction of the nematode population. Based on the result from the C. elegans genome array and indicated in the literatures, stress proteins, metallothionein, vitellogenin, xenobiotic metabolism enzymes, apoptosis-related proteins, and antioxidant enzyme genes were selected as stress-related genes and their expression in C. elegans by DEHP exposure was analyzed semi-quantitatively. Expression of heat shock protein (hsp)-16.1 and hsp-16.2 genes was decreased by DEHP exposure. Expression of cytochrome P450 (cyp) 35a2 and glutathione-S-transferease (gst)-4, phase I and phase II of xenobiotic metabolism enzymes, was increased by DEHP exposure in a concentration-dependent manner. An increase in stress-related gene expressions occurred concomitantly with the deterioration on the physiological level, which suggests an increase in expression of those genes may not be considered as a homeostatic response but as a toxicity that might have physiological consequences. The experiment with the soil from the landfill site suggests that the potential of the C. elegans biomarker identified in laboratory conditions should be calibrated and validated for its use in situ.

  10. Coupling of MIC-3 overexpression with the chromosomes 11 and 14 root-knot nematode (RKN) (Meloidogyne incognita) resistance QTLs provides insights into the regulation of the RKN resistance response in Upland cotton (Gossypium hirsutum).

    Science.gov (United States)

    Wubben, Martin J; Callahan, Franklin E; Jenkins, Johnie N; Deng, Dewayne D

    2016-09-01

    Genetic analysis of MIC-3 transgene with RKN resistance QTLs provides insight into the resistance regulatory mechanism and provides a framework for testing additional hypotheses. Resistance to root-knot nematode (RKN) (Meloidogyne incognita) in Upland cotton (Gossypium hirsutum) is mediated by two major quantitative trait loci (QTL) located on chromosomes 11 and 14. The MIC-3 (Meloidogyne Induced Cotton3) protein accumulates specifically within the immature galls of RKN-resistant plants that possess these QTLs. Recently, we showed that MIC-3 overexpression in an RKN-susceptible cotton genotype suppressed RKN egg production but not RKN-induced root galling. In this study, the MIC-3 overexpression construct T-DNA in the single-copy transgenic line '14-7-1' was converted into a codominant molecular marker that allowed the marker assisted selection of F2:3 cotton lines, derived from a cross between 14-7-1 and M-240 RNR, having all possible combinations of the chromosomes 11 and 14 QTLs with and without the MIC-3 overexpression construct. Root-knot nematode reproduction (eggs g(-1) root) and severity of RKN-induced root galling were assessed in these lines. We discovered that the addition of MIC-3 overexpression suppressed RKN reproduction in lines lacking both resistance QTLs and in lines having only the chromosome 14 QTL, suggesting an additive effect of the MIC-3 construct with this QTL. In contrast, MIC-3 overexpression did not improve resistance in lines having the single chromosome 11 QTL or in lines having both resistance QTLs, suggesting an epistatic interaction between the chromosome 11 QTL and the MIC-3 construct. Overexpression of MIC-3 did not affect the severity of RKN-induced root galling regardless of QTL genotype. These data provide new insights into the relative order of action of the chromosomes 11 and 14 QTLs and their potential roles in regulating MIC-3 expression as part of the RKN resistance response.

  11. The effect of supplementary feeding on the resilience and resistance of browsing Criollo kids against natural gastrointestinal nematode infections during the rainy season in tropical Mexico.

    Science.gov (United States)

    Torres-Acosta, J F J; Jacobs, D E; Aguilar-Caballero, A; Sandoval-Castro, C; May-Martinez, M; Cob-Galera, L A

    2004-10-05

    The objective was to determine the effect of supplementary feeding on the resilience and resistance of Criollo kids against natural gastrointestinal nematode (GIN) infections, when browsing native vegetation during the wet season in tropical Mexico. Thirty-four 2-month old Criollo kids, raised nematode free, were included at weaning in a 22-week trial. The kids were placed into four groups. Two groups of 8 kids were offered 100g/day soybean and sorghum meal (26%:74%, respectively fresh basis) (treated/supplemented (T-S) and infected/supplemented (I-S)). Two groups remained with no supplement for the duration of the trial (infected/non-supplemented (I-NS) (n = 10) and treated/non-supplemented (T-NS) (n = 8)). Kids in groups T-S and T-NS were drenched with 0.2mg of moxidectin/kg body weight orally (Cydectin, Fort Dodge) every 28 days. Groups I-S and I-NS were naturally infected with GIN. The animals browsed native vegetation (for an average of 7h/day) together with a herd of 120 naturally infected adult goats. Cumulative live weight gain (CLWG), packed cell volume (PCV), haemoglobin (Hb), total plasma protein and plasma albumin were recorded every 14 days as measurements of resilience. Resistance parameters (faecal egg counts (FEC) and peripheral eosinophil counts (PEC)) were also measured. Bulk faecal cultures were made for each group every 28 days. Every month a new pair of tracer kids assessed the infectivity of the vegetation browsed by the animals. The T-S group had the highest CLWG, PCV and Hb compared to the other three groups (P 0.05), while the I-NS group had the poorest CLWG, PCV and Hb (P Criollo kids against natural GIN infections and was economically feasible. Improved resistance was also suggested by the PEC but was not confirmed in the FEC.

  12. Sponge microbiota are a reservoir of functional antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Dennis Versluis

    2016-11-01

    Full Text Available Wide application of antibiotics has contributed to the evolution of multi-drug resistant human pathogens, resulting in poorer treatment outcomes for infections. In the marine environment, seawater samples have been investigated as a resistance reservoir; however, no studies have methodically examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n=6, gentamicin (n=1, amikacin (n=7, trimethoprim (n=17, chloramphenicol (n=1, rifampicin (n=2 and ampicillin (n=3. Fifteen of 37 inserts harboured resistance genes that shared <90% amino acid identity with known gene products, whereas on 13 inserts no resistance gene could be identified with high confidence, in which case we predicted resistance to be mainly mediated by antibiotic efflux. One marine-specific ampicillin-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance genes that may be harnessed by phylogenetically distinct bacteria.

  13. Characterization of the Pratylenchus penetrans transcriptome including data mining of putative nematode genes involved in plant parasitism

    Science.gov (United States)

    The root lesion nematode Pratylenchus penetrans is considered one of the most economically important species within the genus. Host range studies have shown that nearly 400 plant species can be parasitized by this species. To obtain insight into the transcriptome of this migratory plant-parasitic ne...

  14. The cfr and cfr-like multiple resistance genes

    DEFF Research Database (Denmark)

    Vester, Birte

    2018-01-01

    . The cfr gene is found in various bacteria in many geographical locations and placed on plasmids or associated with transposons. Cfr-related genes providing similar resistance have been identified in Bacillales, and now also in the pathogens Clostridium difficile and Enterococcus faecium. In addition......, the presence of the cfr gene has been detected in harbours and food markets....

  15. Associations between Antimicrobial Resistance Phenotypes, Antimicrobial Resistance Genes, and Virulence Genes of Fecal Escherichia coli Isolates from Healthy Grow-Finish Pigs ▿

    OpenAIRE

    Rosengren, Leigh B.; Waldner, Cheryl L.; Reid-Smith, Richard J.

    2009-01-01

    Escherichia coli often carries linked antimicrobial resistance genes on transmissible genetic elements. Through coselection, antimicrobial use may select for unrelated but linked resistance or virulence genes. This study used unconditional statistical associations to investigate the relationships between antimicrobial resistance phenotypes and antimicrobial resistance genes in 151 E. coli isolates from healthy pigs. Phenotypic resistance to each drug was significantly associated with phenotyp...

  16. Determination of rust resistance genes in pakistani bread wheats

    International Nuclear Information System (INIS)

    Qamar, M.; Ahmad, S.D.; Rabbani, M.A.; Shinwari, Z.K.

    2014-01-01

    Stripe and leaf rusts are the major constraints to bread wheat production in Pakistan. Molecular markers were used to investigate the presence of leaf rust and stripe rust resistance gene cluster Lr34/Yr18 and stem rust resistance gene Sr2 in 52 Pakistani bread wheat cultivars/lines. PCR amplification of DNA fragments using DNA marker csLV-34 showed that 13 of the studied cultivars/lines, namely 03FJ26, NR 337, NR 339, NR 347, NR 350, Manthar, Margalla 99, Iqbal 2000, Saleem 2000, Wafaq 2001, Marwat 2001, Pirsabak 2004 and Fareed 2006 carry leaf rust and stripe rust resistance genes Lr34/Yr18. Stem rust resistance gene Sr2 was observed in 36 Pakistani spring wheat cultivars/lines using stm560.3tgag marker. The slow rusting gene Sr2 needs to be combined with additional stem rust resistance genes to establish durable resistance against Ug99 in modern wheat cultivars. Low frequency of Lr34/Yr18 was found in Pakistani wheats. This gene cluster needs to be incorporated into Pakistani wheats for durable rust resistance. (author)

  17. The transgenerational effects of heat stress in the nematode Caenorhabditis remanei are negative and rapidly eliminated under direct selection for increased stress resistance in larvae.

    Science.gov (United States)

    Sikkink, Kristin L; Ituarte, Catherine M; Reynolds, Rose M; Cresko, William A; Phillips, Patrick C

    2014-12-01

    Parents encountering stress environments can influence the phenotype of their offspring in a form of transgenerational phenotypic plasticity that has the potential to be adaptive if offspring are thereby better able to deal with future stressors. Here, we test for the existence of anticipatory parental effects in the heat stress response in the highly polymorphic nematode Caenorhabditis remanei. Rather providing an anticipatory response, parents subject to a prior heat stress actually produce offspring that are less able to survive a severe heat shock. Selection on heat shock resistance within the larvae via experimental evolution leads to a loss of sensitivity (robustness) to environmental variation during both the parental and larval periods. Whole genome transcriptional analysis of both ancestor and selected lines shows that there is weak correspondence between genetic pathways induced via temperature shifts during parental and larval periods. Parental effects can evolve very rapidly via selection acting directly on offspring. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Prima facie evidence that a phytocystatin for transgenic plant resistance to nematodes is not a toxic risk in the human diet.

    Science.gov (United States)

    Atkinson, Howard J; Johnston, Katherine A; Robbins, Mark

    2004-02-01

    A protein-engineered rice cystatin (OcIDeltaD86) provides transgenic, partial crop resistance to plant nematodes. This study determined whether its oral uptake has adverse effects on male Sprague-Dawley rats when they are administered by oral gavage 0.1-10 mg OcIDeltaD86/kg body weight daily for 28 d. Body weight and water and food intakes were unaltered for most of the study. The only significant changes in fresh weight of nine organs were for the liver (4% decrease; P 95% loss of such inhibition after 15 s in simulated gastric fluid. The results suggest that the no effect level (NOEL) for OcIDeltaD86 is >10 mg/(kg. d). This provides a range of dietary exposure >200-2000 fold depending upon the promoter used to control its expression in potato.

  19. Expression and evolutionary analyses of three acetylcholinesterase genes (Mi-ace-1, Mi-ace-2, Mi-ace-3) in the root-knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Cui, Ruqiang; Zhang, Lei; Chen, Yuyan; Huang, Wenkun; Fan, Chengming; Wu, Qingsong; Peng, Deliang; da Silva, Washington; Sun, Xiaotang

    2017-05-01

    The full cDNA of Mi-ace-3 encoding an acetylcholinesterase (AChE) in Meloidogyne incognita was cloned and characterized. Mi-ace-3 had an open reading frame of 1875 bp encoding 624 amino acid residues. Key residues essential to AChE structure and function were conserved. The deduced Mi-ACE-3 protein sequence had 72% amino acid similarity with that of Ditylenchus destructor Dd-AChE-3. Phylogenetic analyses using 41 AChEs from 24 species showed that Mi-ACE-3 formed a cluster with 4 other nematode AChEs. Our results revealed that the Mi-ace-3 cloned in this study, which is orthologous to Caenorhabditis elegans AChE, belongs to the nematode ACE-3/4 subgroup. There was a significant reduction in the number of galls in transgenic tobacco roots when Mi-ace-1, Mi-ace-2, and Mi-ace-3 were knocked down simultaneously, whereas little or no effect were observed when only one or two of these genes were knocked down. This is an indication that the functions of these three genes are redundant. Copyright © 2017. Published by Elsevier Inc.

  20. Isolation of NBS-LRR class resistant gene (I2 gene) from tomato ...

    African Journals Online (AJOL)

    aghomotsegin

    2013-10-16

    Oct 16, 2013 ... type of F. oxysporum f. sp. lycopersici observed commonly which require presence of I1 gene in tomato plant for the incompatibility ... Key words: Fusarium wilt, race, R-gene, resistance, tomato. ... MATERIALS AND METHODS.

  1. Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control.

    Directory of Open Access Journals (Sweden)

    Qing-Bin Yuan

    Full Text Available This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L. The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L. By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L. However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.

  2. Efficacy of a combined oral formulation of derquantel-abamectin against the adult and larval stages of nematodes in sheep, including anthelmintic-resistant strains.

    Science.gov (United States)

    Little, Peter R; Hodge, Andrew; Maeder, Steven J; Wirtherle, Nicole C; Nicholas, David R; Cox, George G; Conder, George A

    2011-09-27

    Derquantel (DQL), a semi-synthetic member of a novel anthelmintic class, the spiroindoles, in combination with abamectin (ABA) [as the combination product STARTECT(®)] is a new entry for the treatment and control of parasites in sheep. The 19 studies reported herein were conducted in Australia, New Zealand, South Africa and the United Kingdom to demonstrate the efficacy of derquantel-abamectin (DQL-ABA) against a broad spectrum of gastrointestinal and respiratory nematodes of sheep, and to support registration of the combination product. Eleven studies were conducted using natural or experimental parasite infections with unknown or unconfirmed resistance, while eight studies utilised isolates/strains with confirmed or well characterised resistance to one or more currently available anthelmintics, including macrocyclic lactones. All studies included DQL-ABA and negative control groups, and in selected studies one or more reference anthelmintic groups were included. In all studies the commercial formulation of DQL-ABA was administered orally at 2mg/kg DQL and 0.2mg/kg ABA; placebo was administered in the same volume as DQL-ABA; and reference anthelmintics were administered as per label recommendations, except in one instance where levamisole was administered at twice the label dose. Infection, necropsy, worm collection and worm counting procedures were performed using standard techniques. Efficacy was calculated based on the percentage reduction in geometric mean worm count relative to negative control for each nematode species and lifecycle stage targeted. Twenty-two isolates/strains used in the eight studies targeting resistant worms had proven resistance: three to one anthelmintic class, eleven to two classes and eight to three or more classes; of these resistant strains, 16 demonstrated resistance to a macrocyclic lactone anthelmintic. Regardless of resistance status in the 19 studies, DQL-ABA controlled a broad range of economically important gastrointestinal

  3. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    Science.gov (United States)

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  4. Transcriptional profiling of root-knot nematode induced feeding sites in cowpea (Vigna unguiculata L. Walp. using a soybean genome array

    Directory of Open Access Journals (Sweden)

    Das Sayan

    2010-08-01

    Full Text Available Abstract Background The locus Rk confers resistance against several species of root-knot nematodes (Meloidogyne spp., RKN in cowpea (Vigna unguiculata. Based on histological and reactive oxygen species (ROS profiles, Rk confers a delayed but strong resistance mechanism without a hypersensitive reaction-mediated cell death process, which allows nematode development but blocks reproduction. Results Responses to M. incognita infection in roots of resistant genotype CB46 and a susceptible near-isogenic line (null-Rk were investigated using a soybean Affymetrix GeneChip expression array at 3 and 9 days post-inoculation (dpi. At 9 dpi 552 genes were differentially expressed in incompatible interactions (infected resistant tissue compared with non-infected resistant tissue and 1,060 genes were differentially expressed in compatible interactions (infected susceptible tissue compared with non-infected susceptible tissue. At 3 dpi the differentially expressed genes were 746 for the incompatible and 623 for the compatible interactions. When expression between infected resistant and susceptible genotypes was compared, 638 and 197 genes were differentially expressed at 9 and 3 dpi, respectively. Conclusions In comparing the differentially expressed genes in response to nematode infection, a greater number and proportion of genes were down-regulated in the resistant than in the susceptible genotype, whereas more genes were up-regulated in the susceptible than in the resistant genotype. Gene ontology based functional categorization revealed that the typical defense response was partially suppressed in resistant roots, even at 9 dpi, allowing nematode juvenile development. Differences in ROS concentrations, induction of toxins and other defense related genes seem to play a role in this unique resistance mechanism.

  5. Screening of in vitro derived mutants of banana against nematodes ...

    African Journals Online (AJOL)

    The rest of the mutants namely Ro Im V4 6-1-2 and Si Im V4 6-2-5 were found to be susceptible to nematodes. The resistant and moderately resistant mutants of banana could be further used in breeding programmes as well as being recognized as potential cultivars of commerce. Key words: Banana, nematode, resistance, ...

  6. Are duplicated genes responsible for anthracnose resistance in common bean?

    Science.gov (United States)

    Costa, Larissa Carvalho; Nalin, Rafael Storto; Ramalho, Magno Antonio Patto; de Souza, Elaine Aparecida

    2017-01-01

    The race 65 of Colletotrichum lindemuthianum, etiologic agent of anthracnose in common bean, is distributed worldwide, having great importance in breeding programs for anthracnose resistance. Several resistance alleles have been identified promoting resistance to this race. However, the variability that has been detected within race has made it difficult to obtain cultivars with durable resistance, because cultivars may have different reactions to each strain of race 65. Thus, this work aimed at studying the resistance inheritance of common bean lines to different strains of C. lindemuthianum, race 65. We used six C. lindemuthianum strains previously characterized as belonging to the race 65 through the international set of differential cultivars of anthracnose and nine commercial cultivars, adapted to the Brazilian growing conditions and with potential ability to discriminate the variability within this race. To obtain information on the resistance inheritance related to nine commercial cultivars to six strains of race 65, these cultivars were crossed two by two in all possible combinations, resulting in 36 hybrids. Segregation in the F2 generations revealed that the resistance to each strain is conditioned by two independent genes with the same function, suggesting that they are duplicated genes, where the dominant allele promotes resistance. These results indicate that the specificity between host resistance genes and pathogen avirulence genes is not limited to races, it also occurs within strains of the same race. Further research may be carried out in order to establish if the alleles identified in these cultivars are different from those described in the literature.

  7. Overexpression of antibiotic resistance genes in hospital effluents over time.

    Science.gov (United States)

    Rowe, Will P M; Baker-Austin, Craig; Verner-Jeffreys, David W; Ryan, Jim J; Micallef, Christianne; Maskell, Duncan J; Pearce, Gareth P

    2017-06-01

    Effluents contain a diverse abundance of antibiotic resistance genes that augment the resistome of receiving aquatic environments. However, uncertainty remains regarding their temporal persistence, transcription and response to anthropogenic factors, such as antibiotic usage. We present a spatiotemporal study within a river catchment (River Cam, UK) that aims to determine the contribution of antibiotic resistance gene-containing effluents originating from sites of varying antibiotic usage to the receiving environment. Gene abundance in effluents (municipal hospital and dairy farm) was compared against background samples of the receiving aquatic environment (i.e. the catchment source) to determine the resistome contribution of effluents. We used metagenomics and metatranscriptomics to correlate DNA and RNA abundance and identified differentially regulated gene transcripts. We found that mean antibiotic resistance gene and transcript abundances were correlated for both hospital ( ρ  = 0.9, two-tailed P  hospital effluent samples. High β-lactam resistance gene transcript abundance was related to hospital antibiotic usage over time and hospital effluents contained antibiotic residues. We conclude that effluents contribute high levels of antibiotic resistance genes to the aquatic environment; these genes are expressed at significant levels and are possibly related to the level of antibiotic usage at the effluent source. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

  8. Influence of Bxpel1 Gene Silencing by dsRNA Interference on the Development and Pathogenicity of the Pine Wood Nematode, Bursaphelenchus xylophilus

    Science.gov (United States)

    Qiu, Xiu-Wen; Wu, Xiao-Qin; Huang, Lin; Ye, Jian-Ren

    2016-01-01

    As the causal agent of pine wilt disease (PWD), the pine wood nematode (PWN), Bursaphelenchus xylophilus, causes huge economic losses by devastating pine forests worldwide. The pectate lyase gene is essential for successful invasion of their host plants by plant-parasitic nematodes. To demonstrate the role of pectate lyase gene in the PWD process, RNA interference (RNAi) is used to analyze the function of the pectate lyase 1 gene in B. xylophilus (Bxpel1). The efficiency of RNAi was detected by real-time PCR. The result demonstrated that the quantity of B. xylophilus propagated with control solution treatment was 62 times greater than that soaking in double-stranded RNA (dsRNA) after B. xylophilus inoculation in Botrytis cinerea for the first generation (F1). The number of B. xylophilus soaking in control solution was doubled compared to that soaking in Bxpel1 dsRNA four days after inoculation in Pinus thunbergii. The quantity of B. xylophilus was reduced significantly (p < 0.001) after treatment with dsRNAi compared with that using a control solution treatment. Bxpel1 dsRNAi reduced the migration speed and reproduction of B. xylophilus in pine trees. The pathogenicity to P. thunbergii seedling of B. xylophilus was weaker after soaking in dsRNA solution compared with that after soaking in the control solution. Our results suggest that Bxpel1 gene is a significant pathogenic factor in the PWD process and this basic information may facilitate a better understanding of the molecular mechanism of PWD. PMID:26797602

  9. Genome Evolution of Plant-Parasitic Nematodes.

    Science.gov (United States)

    Kikuchi, Taisei; Eves-van den Akker, Sebastian; Jones, John T

    2017-08-04

    Plant parasitism has evolved independently on at least four separate occasions in the phylum Nematoda. The application of next-generation sequencing (NGS) to plant-parasitic nematodes has allowed a wide range of genome- or transcriptome-level comparisons, and these have identified genome adaptations that enable parasitism of plants. Current genome data suggest that horizontal gene transfer, gene family expansions, evolution of new genes that mediate interactions with the host, and parasitism-specific gene regulation are important adaptations that allow nematodes to parasitize plants. Sequencing of a larger number of nematode genomes, including plant parasites that show different modes of parasitism or that have evolved in currently unsampled clades, and using free-living taxa as comparators would allow more detailed analysis and a better understanding of the organization of key genes within the genomes. This would facilitate a more complete understanding of the way in which parasitism has shaped the genomes of plant-parasitic nematodes.

  10. Mining the secretome of root-knot nematodes for cell wall modifying proteins

    NARCIS (Netherlands)

    Roze, E.H.A.

    2008-01-01

    The products of parasitism genes in nematodes must be secreted to reach their targets at the nematode-plant interface. These nematode secretory proteins are therefore recognised to play an important role in the nematode-plant interaction and as a result have been subject of intense study for years.

  11. Induced resistance and gene expression in wheat against leaf rust ...

    African Journals Online (AJOL)

    uvp

    2013-05-15

    May 15, 2013 ... 2Department of Soil, Crop and Climate Sciences, University of the Free State, P.O Box ... Key words: Wheat leaf rust, induced resistance, priming, gene ..... transformation: susceptibility of transgenic Nicotiana sylvestris plants.

  12. Molecular Detection of Virulence Genes and Antibiotic Resistance ...

    African Journals Online (AJOL)

    Pathogen, E. coli O157:H7, virulence genes, antibiotic-resistance, beef meat. Correspondence: ... box to the laboratory for further processing. Isolation and identification of ... Technologies (IDT) Inc, U.S.A. The sequences and annealing ...

  13. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    PUNEET INDER TOOR

    A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated .... infector rows and experimental material with the mixture of uredinospores of Pst ...

  14. Resistance gene management: concepts and practice

    Science.gov (United States)

    Christopher C. Mundt

    2012-01-01

    There is now a very long history of genetics/breeding for disease resistance in annual crops. These efforts have resulted in conceptual advances and frustrations, as well as practical successes and failures. This talk will review this history and its relevance to the genetics of resistance in forest species. All plant breeders and pathologists are familiar with boom-...

  15. Gene Expression Analysis of Four Radiation-resistant Bacteria

    OpenAIRE

    Gao, Na; Ma, Bin-Guang; Zhang, Yu-Sheng; Song, Qin; Chen, Ling-Ling; Zhang, Hong-Yu

    2009-01-01

    To investigate the general radiation-resistant mechanisms of bacteria, bioinformatic method was employed to predict highly expressed genes for four radiation-resistant bacteria, i.e. Deinococcus geothermalis (D. geo), Deinococcus radiodurans (D. rad), Kineococcus radiotolerans (K. rad) and Rubrobacter xylanophilus (R. xyl). It is revealed that most of the three reference gene sets, i.e. ribosomal proteins, transcription factors and major chaperones, are generally highly expressed in the four ...

  16. Overexpression of antibiotic resistance genes in hospital effluents over time

    OpenAIRE

    Rowe, Will P. M.; Baker-Austin, Craig; Verner-Jeffreys, David W.; Ryan, Jim J.; Micallef, Christianne; Maskell, Duncan J.; Pearce, Gareth P.

    2017-01-01

    $\\textbf{Objectives}$: Effluents contain a diverse abundance of antibiotic resistance genes that augment the resistome of receiving aquatic environments. However, uncertainty remains regarding their temporal persistence, transcription and response to anthropogenic factors, such as antibiotic usage. We present a spatiotemporal study within a river catchment (River Cam, UK) that aims to determine the contribution of antibiotic resistance gene-containing effluents originating from sites of varyi...

  17. Characterization of an acetylcholine receptor gene of Haemonchus contortus in relation to levamisole resistance

    NARCIS (Netherlands)

    Hoekstra, R.; Visser, A.; Wiley, L. J.; Weiss, A. S.; Sangster, N. C.; Roos, M. H.

    1997-01-01

    The anthelminitic drug levamisole is thought to bind to nicotinic acetylcholine receptors of nematodes. It is possible that resistance to this drug is associated with either a change in binding characteristics or a reduction in the number of nicotinic acetylcholine receptors. Therefore, the

  18. Characterisation of an acetylcholine receptor gene of Haemonchus contortus in relation to levamisole resistance

    NARCIS (Netherlands)

    Hoekstra, R.; Visser, A.; Wiley, L.; Weiss, A.S.; Sangster, N.C.; Roos, M.H.

    1997-01-01

    The anthelmintic drug levamisole is thought to bind to nicotinic acetylcholine receptors of nematodes. It is possible that resistance to this drug is associated with either a change in binding characteristics or a reduction in the number of nicotinic acetylcholine receptors. Therefore, the molecular

  19. Analysis of metal and biocides resistance genes in drug resistance and susceptible Salmonella enterica from food animals

    Science.gov (United States)

    Background Generally drug resistant bacteria carry antibiotic resistance genes and heavy metal and biocide resistance genes on large conjugative plasmids. The presence of these metal and biocide resistance genes in susceptible bacteria are not assessed comprehensively. Hence, WGS data of susceptib...

  20. The antimicrobial resistance crisis: management through gene monitoring

    Science.gov (United States)

    2016-01-01

    Antimicrobial resistance (AMR) is an acknowledged crisis for humanity. Its genetic origins and dire potential outcomes are increasingly well understood. However, diagnostic techniques for monitoring the crisis are currently largely limited to enumerating the increasing incidence of resistant pathogens. Being the end-stage of the evolutionary process that produces antimicrobial resistant pathogens, these measurements, while diagnostic, are not prognostic, and so are not optimal in managing this crisis. A better test is required. Here, using insights from an understanding of evolutionary processes ruling the changing abundance of genes under selective pressure, we suggest a predictive framework for the AMR crisis. We then discuss the likely progression of resistance for both existing and prospective antimicrobial therapies. Finally, we suggest that by the environmental monitoring of resistance gene frequency, resistance may be detected and tracked presumptively, and how this tool may be used to guide decision-making in the local and global use of antimicrobials. PMID:27831476

  1. The Number of Genes Controlling Resistance in Beans to Common ...

    African Journals Online (AJOL)

    Ten crosses were made between resistant (R), susceptible (S), RxS susceptible and Intermediate (I), SxI and RxR bean lines to common bacterial blight. The F1 were advanced to F2 and in each cross over 250 F2 plants were used to evaluate for the number of genes controlling resistance using Mendelian genetics and ...

  2. Prevalence, antibiotic-resistance properties and enterotoxin gene ...

    African Journals Online (AJOL)

    Prevalence, antibiotic-resistance properties and enterotoxin gene profile of Bacillus cereus strains isolated from milk-based baby foods. ... Conclusion: Considerable prevalence of resistant and toxigenic B. cereus and high consumption of milk-based infant foods in Iran, represent an important public health issue which ...

  3. Spread of tetracycline resistance genes at a conventional dairy farm

    NARCIS (Netherlands)

    Kyselková, Martina; Jirout, Jiří; Vrchotová, Naděžda; Schmitt, Heike; Elhottová, Dana

    2015-01-01

    The use of antibiotics in animal husbandry contributes to the worldwide problem of increasing antibiotic resistance in animal and human pathogens. Intensive animal production is considered an important source of antibiotic resistance genes released to the environment, while the contribution of

  4. Isolation and characterization of a candidate gene for resistance to ...

    African Journals Online (AJOL)

    ARC) domain, and a leucine-rich repeat (LRR) domain, all of which are typical characteristics of resistance genes. We proposed the resistance mechanism of CreV8 based on functional analysis and predictions from its conserved domains and ...

  5. Pediatric fecal microbiota harbor diverse and novel antibiotic resistance genes.

    Directory of Open Access Journals (Sweden)

    Aimée M Moore

    Full Text Available Emerging antibiotic resistance threatens human health. Gut microbes are an epidemiologically important reservoir of resistance genes (resistome, yet prior studies indicate that the true diversity of gut-associated resistomes has been underestimated. To deeply characterize the pediatric gut-associated resistome, we created metagenomic recombinant libraries in an Escherichia coli host using fecal DNA from 22 healthy infants and children (most without recent antibiotic exposure, and performed functional selections for resistance to 18 antibiotics from eight drug classes. Resistance-conferring DNA fragments were sequenced (Illumina HiSeq 2000, and reads assembled and annotated with the PARFuMS computational pipeline. Resistance to 14 of the 18 antibiotics was found in stools of infants and children. Recovered genes included chloramphenicol acetyltransferases, drug-resistant dihydrofolate reductases, rRNA methyltransferases, transcriptional regulators, multidrug efflux pumps, and every major class of beta-lactamase, aminoglycoside-modifying enzyme, and tetracycline resistance protein. Many resistance-conferring sequences were mobilizable; some had low identity to any known organism, emphasizing cryptic organisms as potentially important resistance reservoirs. We functionally confirmed three novel resistance genes, including a 16S rRNA methylase conferring aminoglycoside resistance, and two tetracycline-resistance proteins nearly identical to a bifidobacterial MFS transporter (B. longum s. longum JDM301. We provide the first report to our knowledge of resistance to folate-synthesis inhibitors conferred by a predicted Nudix hydrolase (part of the folate synthesis pathway. This functional metagenomic survey of gut-associated resistomes, the largest of its kind to date, demonstrates that fecal resistomes of healthy children are far more diverse than previously suspected, that clinically relevant resistance genes are present even without recent selective

  6. Cloning and characterization of NBS-LRR resistance gene ...

    African Journals Online (AJOL)

    biotech

    2013-07-03

    Jul 3, 2013 ... Rose using degernate primers designed from the conserved motifs of different plant resistance genes. A total of 40 sequences were hit with various R genes, of which 20 .... absorption ratio OD260 nm/OD280 nm between 1.80 and ..... status and outlook for small-holders agriculture in C S Gold and B.

  7. Induced mutations of rust resistance genes in wheat

    International Nuclear Information System (INIS)

    McIntosh, R.A.

    1983-01-01

    Induced mutations are being used as a tool to study genes for resistance in wheat. It was found that Pm1 can be separated from Lr20 and Sr15, but these two react like a single pleiotropic gene. Mutants were further examined in crosses and backmutations have been attempted. (author)

  8. Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance

    DEFF Research Database (Denmark)

    Huang, Laurence; Crothers, Kristina; Atzori, Chiara

    2004-01-01

    in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim...

  9. Testing of disease-resistance of pokeweed antiviral protein gene ...

    African Journals Online (AJOL)

    Transformation of pokeweed antiviral protein gene (PAP) into plants was shown to improve plant resistance to several viruses or fungi pathogens with no much negative effect on plant growth. The non-virulent defective PAP inhibits only the virus but does not interfere with the host. A non-virulent defective PAP gene ...

  10. Resistance gene candidates identified by PCR with degenerate oligonucleotide primers map to clusters of resistance genes in lettuce.

    Science.gov (United States)

    Shen, K A; Meyers, B C; Islam-Faridi, M N; Chin, D B; Stelly, D M; Michelmore, R W

    1998-08-01

    The recent cloning of genes for resistance against diverse pathogens from a variety of plants has revealed that many share conserved sequence motifs. This provides the possibility of isolating numerous additional resistance genes by polymerase chain reaction (PCR) with degenerate oligonucleotide primers. We amplified resistance gene candidates (RGCs) from lettuce with multiple combinations of primers with low degeneracy designed from motifs in the nucleotide binding sites (NBSs) of RPS2 of Arabidopsis thaliana and N of tobacco. Genomic DNA, cDNA, and bacterial artificial chromosome (BAC) clones were successfully used as templates. Four families of sequences were identified that had the same similarity to each other as to resistance genes from other species. The relationship of the amplified products to resistance genes was evaluated by several sequence and genetic criteria. The amplified products contained open reading frames with additional sequences characteristic of NBSs. Hybridization of RGCs to genomic DNA and to BAC clones revealed large numbers of related sequences. Genetic analysis demonstrated the existence of clustered multigene families for each of the four RGC sequences. This parallels classical genetic data on clustering of disease resistance genes. Two of the four families mapped to known clusters of resistance genes; these two families were therefore studied in greater detail. Additional evidence that these RGCs could be resistance genes was gained by the identification of leucine-rich repeat (LRR) regions in sequences adjoining the NBS similar to those in RPM1 and RPS2 of A. thaliana. Fluorescent in situ hybridization confirmed the clustered genomic distribution of these sequences. The use of PCR with degenerate oligonucleotide primers is therefore an efficient method to identify numerous RGCs in plants.

  11. Timecourse microarray analyses reveal global changes in gene expression of susceptible Glycine max (soybean) roots during infection by Heterodera glycines (soybean cyst nematode).

    Science.gov (United States)

    Alkharouf, Nadim W; Klink, Vincent P; Chouikha, Imed B; Beard, Hunter S; MacDonald, Margaret H; Meyer, Susan; Knap, Halina T; Khan, Rana; Matthews, Benjamin F

    2006-09-01

    Changes in gene expression within roots of Glycine max (soybean), cv. Kent, susceptible to infection by Heterodera glycines (the soybean cyst nematode [SCN]), at 6, 12, and 24 h, and 2, 4, 6, and 8 days post-inoculation were monitored using microarrays containing more than 6,000 cDNA inserts. Replicate, independent biological samples were examined at each time point. Gene expression was analyzed statistically using T-tests, ANOVA, clustering algorithms, and online analytical processing (OLAP). These analyses allow the user to query the data in several ways without importing the data into third-party software. RT-PCR confirmed that WRKY6 transcription factor, trehalose phosphate synthase, EIF4a, Skp1, and CLB1 were differentially induced across most time-points. Other genes induced across most timepoints included lipoxygenase, calmodulin, phospholipase C, metallothionein-like protein, and chalcone reductase. RT-PCR demonstrated enhanced expression during the first 12 h of infection for Kunitz trypsin inhibitor and sucrose synthase. The stress-related gene, SAM-22, phospholipase D and 12-oxophytodienoate reductase were also induced at the early time-points. At 6 and 8 dpi there was an abundance of transcripts expressed that encoded genes involved in transcription and protein synthesis. Some of those genes included ribosomal proteins, and initiation and elongation factors. Several genes involved in carbon metabolism and transport were also more abundant. Those genes included glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase and sucrose synthase. These results identified specific changes in gene transcript levels triggered by infection of susceptible soybean roots by SCN.

  12. Comparison of antibiotic resistance, virulence gene profiles, and pathogenicity of methicillin-resistant and methicillin-susceptible Staphylococcus aureus using a Caenorhabditis elegans infection model

    Science.gov (United States)

    Thompson, Terissa; Brown, Paul D

    2014-01-01

    Objectives: This study compared the presence of 35 virulence genes, resistance phenotypes to 11 anti-staphylococcal antibiotics, and pathogenicity in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). Methods: Multiplex PCR analysis was used to differentiate Staphylococcus aureus isolates (n = 102) based on characterization of the Staphylococcal Cassette Chromosome mec (SCCmec). Singleplex and multiplex PCR assays targeting 35 virulence determinants were used to analyze the virulence repertoire of S. aureus. In vitro activities of the antibiotics were determined by the disk-diffusion method. The pathogenicity of representative isolates was assessed using Caenorhabditis elegans survival assays. Significance in virulence distribution and antibiotic resistance phenotypes was assessed using the Chi-squared tests. Kaplan–Meier survival estimates were used to analyze nematode survival and significance of survival rates evaluated using the log-rank test. Results: Except for sei (staphylococcal enterotoxin I) (P  =  0.027), all other virulence genes were not significantly associated with MRSA. Resistance to clindamycin (P  =  0.03), tetracycline (P  =  0.048), trimethoprim/sulfamethoxazole (P  =  0.038), and oxacillin (P  =  0.004) was significantly associated with MRSA. Survival assay showed MSSA having a lower median lifespan of 3 days than MRSA that had a median lifespan of 6 days. The difference in the killing time of MRSA and MSSA was significant (P virulence genes. The quicker killing potential of MSSA compared to MRSA suggests that carriage of virulence determinants per se does not determine pathogenicity in S. aureus. Pathogenicity is impacted by other factors, possibly antibiotic resistance. PMID:25319852

  13. Environmental cycle of antibiotic resistance encoded genes: A systematic review

    Directory of Open Access Journals (Sweden)

    R. ghanbari

    2017-12-01

    Full Text Available Antibiotic-resistant bacteria and genes enter the environment in different ways. The release of these factors into the environment has increased concerns related to public health. The aim of the study was to evaluate the antibiotic resistance genes (ARGs in the environmental resources. In this systematic review, the data were extracted from valid sources of information including ScienceDirect, PubMed, Google Scholar and SID. Evaluation and selection of articles were conducted on the basis of the PRISMA checklist. A total of 39 articles were included in the study, which were chosen from a total of 1249 papers. The inclusion criterion was the identification of genes encoding antibiotic resistance against the eight important groups of antibiotics determined by using the PCR technique in the environmental sources including municipal and hospital wastewater treatment plants, animal and agricultural wastes, effluents from treatment plants, natural waters, sediments, and drinking waters. In this study, 113 genes encoding antibiotic resistance to eight groups of antibiotics (beta-lactams, aminoglycosides, tetracyclines, macrolides, sulfonamides, chloramphenicol, glycopeptides and quinolones were identified in various environments. Antibiotic resistance genes were found in all the investigated environments. The investigation of microorganisms carrying these genes shows that most of the bacteria especially gram-negative bacteria are effective in the acquisition and the dissemination of these pollutants in the environment. Discharging the raw wastewaters and effluents from wastewater treatments acts as major routes in the dissemination of ARGs into environment sources and can pose hazards to public health.

  14. RESISTANCE-RELATED GENE TRANSCRIPTION AND ...

    African Journals Online (AJOL)

    jdx

    2014-02-05

    Feb 5, 2014 ... By 72 hpi, the pathogen switched to necrotrophic growth to avoid contact with the increasing ... A better understanding of the gene network underlying ... 5.0 software under default parameters and were custom-ordered.

  15. The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

    Science.gov (United States)

    Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

    2017-07-01

    The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  16. Antibiotic resistance and virulence genes in coliform water isolates.

    Science.gov (United States)

    Stange, C; Sidhu, J P S; Tiehm, A; Toze, S

    2016-11-01

    Widespread fecal pollution of surface water may present a major health risk and a significant pathway for dissemination of antibiotic resistance bacteria. The River Rhine is one of the longest and most important rivers in Europe and an important raw water source for drinking water production. A total of 100 coliform isolates obtained from River Rhine (Germany) were examined for their susceptibility to seven antimicrobial agents. Resistances against amoxicillin, trimethoprim/sulfamethoxazole and tetracycline were detected in 48%, 11% and 9% of isolates respectively. The antibiotic resistance could be traced back to the resistance genes bla TEM , bla SHV , ampC, sul1, sul2, dfrA1, tet(A) and tet(B). Whereby, the ampC gene represents a special case, because its presence is not inevitably linked to a phenotypic antibiotic resistance. Multiple antibiotics resistance was often accompanied by the occurrence of class 1 or 2 integrons. E. coli isolates belonging to phylogenetic groups A and B1 (commensal) were more predominant (57%) compared to B2 and D groups (43%) which are known to carry virulent genes. Additionally, six E. coli virulence genes were also detected. However, the prevalence of virulence genes in the E. coli isolates was low (not exceeding 4.3% per gene) and no diarrheagenic E. coli pathotypes were detected. This study demonstrates that surface water is an important reservoir of ARGs for a number of antibiotic classes such as sulfonamide, trimethoprim, beta-lactam-antibiotics and tetracycline. The occurrence of antibiotic resistance in coliform bacteria isolated from River Rhine provides evidence for the need to develop management strategies to limit the spread of antibiotic resistant bacteria in aquatic environment. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, Kira S.; Omelchenko, Marina V.; Gaidamakova, Elena K.; Matrosova, Vera Y.; Vasilenko, Alexander; Zhai, Min; Lapidus, Alla; Copeland, Alex; Kim, Edwin; Land, Miriam; Mavrommatis, Konstantinos; Pitluck, Samuel; Richardson, Paul M.; Detter, Chris; Brettin, Thomas; Saunders, Elizabeth; Lai, Barry; Ravel, Bruce; Kemner, Kenneth M.; Wolf, Yuri I.; Sorokin, Alexander; Gerasimova, Anna V.; Gelfand, Mikhail S.; Fredrickson, James K.; Koonin, Eugene V.; Daly, Michael J.

    2007-07-24

    Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at itsoptimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to

  18. Identifying resistance gene analogs associated with resistances to different pathogens in common bean.

    Science.gov (United States)

    López, Camilo E; Acosta, Iván F; Jara, Carlos; Pedraza, Fabio; Gaitán-Solís, Eliana; Gallego, Gerardo; Beebe, Steve; Tohme, Joe

    2003-01-01

    ABSTRACT A polymerase chain reaction approach using degenerate primers that targeted the conserved domains of cloned plant disease resistance genes (R genes) was used to isolate a set of 15 resistance gene analogs (RGAs) from common bean (Phaseolus vulgaris). Eight different classes of RGAs were obtained from nucleotide binding site (NBS)-based primers and seven from not previously described Toll/Interleukin-1 receptor-like (TIR)-based primers. Putative amino acid sequences of RGAs were significantly similar to R genes and contained additional conserved motifs. The NBS-type RGAs were classified in two subgroups according to the expected final residue in the kinase-2 motif. Eleven RGAs were mapped at 19 loci on eight linkage groups of the common bean genetic map constructed at Centro Internacional de Agricultura Tropical. Genetic linkage was shown for eight RGAs with partial resistance to anthracnose, angular leaf spot (ALS) and Bean golden yellow mosaic virus (BGYMV). RGA1 and RGA2 were associated with resistance loci to anthracnose and BGYMV and were part of two clusters of R genes previously described. A new major cluster was detected by RGA7 and explained up to 63.9% of resistance to ALS and has a putative contribution to anthracnose resistance. These results show the usefulness of RGAs as candidate genes to detect and eventually isolate numerous R genes in common bean.

  19. The relationship between codon usage bias and cold resistant genes

    International Nuclear Information System (INIS)

    Barozai, M.Y.; Din, M.

    2014-01-01

    This research is based on synonymous codon usage which has been well-known as a feature that affects typical expression level of protein in an organism. Different organisms prefer different codons for same amino acid and this is called Codon Usage Bias (CUB). The codon usage directly affects the level or even direction of changes in protein expression in responses to environmental stimuli. Cold stress is a major abiotic factor that limits the agricultural productivity of plants. In the recent study CUB has been studied in Arabidopsis thaliana cold resistant and housekeeping genes and their homologs in rice (Oryza sativa) to understand the cold stress and housekeeping genes relation with CUB. Six cold resistant and three housekeeping genes in Arabidopsis thaliana and their homologs in rice, were subjected to CUB analysis. The three cold resistant genes (DREB1B, RCI and MYB15) showed more than 50% (52%, 61% and 66% respectively) similar codon usage bias for Arabidopsis thaliana and rice. On the other hand three cold resistant genes (MPK3, ICE1 and ZAT12) showed less than 50% (38%, 38% and 47% respectively) similar codon usage bias for Arabidopsis thaliana and rice. The three housekeeping genes (Actin, Tubulin and Ubiquitin) showed 76% similar codon usage bias for Arabidopsis thaliana and rice. This study will help to manage the plant gene expression through codon optimization under the cold stress. (author)

  20. Persistence of antimicrobial resistance genes from sows to finisher pigs

    DEFF Research Database (Denmark)

    Birkegård, Anna Camilla; Halasa, Tariq; Folkesson, Anders

    2018-01-01

    Antimicrobial resistance in pigs has been under scrutiny for many years. However, many questions remain unanswered, including whether the initial antimicrobial resistance level of a pig will influence the antimicrobial resistance found at slaughter. Faecal samples from finishers pigs from 681 farms...... and from sows from 82 farms were collected, and levels of seven antimicrobial resistance genes, ermB, ermF, sulI, sulII, tet(M), tet(O), and tet(W), were quantified by high-capacity qPCR. There were 40 pairs of observations where the finishers were born in the farms of the sows. The objective of this study...

  1. Molecular screening for erythromycin resistance genes in ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-07-15

    Jul 15, 2015 ... in Streptococcus pyogenes isolated from Iraqi patients with tonsilo-pharyngites. Hassan .... is an automated colorimetric method used for identification of bacteria and for .... counter medicines in private pharmacies against the regulations. ... Effect of telithromycin on erythromycin resistant S. pyogenes. In this ...

  2. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA

    Directory of Open Access Journals (Sweden)

    Bertinellys TEIXEIRA

    2016-01-01

    Full Text Available The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC, aminoglycoside-adenyltransferases (AAD, and aminoglycoside-phosphotransferases (APH, is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137 were identified from the Intensive Care Unit (ICU, mainly from discharges (96/137. The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively. Phenotype VI, resistant to these antibiotics, was the most frequent (14/49, followed by phenotype I, resistant to all the aminoglycosides tested (12/49. The aac(6´-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  3. Genetic mapping and pyramiding of resistance genes in potato

    NARCIS (Netherlands)

    Tan, M.Y.A.

    2008-01-01

    Numerous pathogens can infect potato, but late blight (Phytophthora infestans (Mont.) de Bary) and potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida are most damaging. Several species of root knot nematodes (RKN) are an emerging threat. Breeders have successfully deployed disease

  4. Molecular Scree ning of Blast Resistance Genes in Rice Germplasms Resistant to Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Liang Yan

    2017-01-01

    Full Text Available Molecular screening of major rice blast resistance genes was determined with molecular markers, which showed close-set linkage to 11 major rice blast resistance genes (Pi-d2, Pi-z, Piz-t, Pi-9, Pi-36, Pi-37, Pi5, Pi-b, Pik-p, Pik-h and Pi-ta2, in a collection of 32 accessions resistant to Magnaporthe oryzae. Out of the 32 accessions, the Pi-d2 and Pi-z appeared to be omnipresent and gave positive express. As the second dominant, Pi-b and Piz-t gene frequencies were 96.9% and 87.5%. And Pik-h and Pik-p gene frequencies were 43.8% and 28.1%, respectively. The molecular marker linkage to Pi-ta2 produced positive bands in eleven accessions, while the molecular marker linkage to Pi-36 and Pi-37 in only three and four accessions, respectively. The natural field evaluation analysis showed that 30 of the 32 accessions were resistant, one was moderately resistant and one was susceptible. Infection types were negatively correlated with the genotype scores of Pi-9, Pi5, Pi-b, Pi-ta2 and Pik-p, although the correlation coefficients were very little. These results are useful in identification and incorporation of functional resistance genes from these germplasms into elite cultivars through marker-assisted selection for improved blast resistance in China and worldwide.

  5. Mechanisms of host seeking by parasitic nematodes.

    Science.gov (United States)

    Gang, Spencer S; Hallem, Elissa A

    2016-07-01

    The phylum Nematoda comprises a diverse group of roundworms that includes parasites of vertebrates, invertebrates, and plants. Human-parasitic nematodes infect more than one billion people worldwide and cause some of the most common neglected tropical diseases, particularly in low-resource countries [1]. Parasitic nematodes of livestock and crops result in billions of dollars in losses each year [1]. Many nematode infections are treatable with low-cost anthelmintic drugs, but repeated infections are common in endemic areas and drug resistance is a growing concern with increasing therapeutic and agricultural administration [1]. Many parasitic nematodes have an environmental infective larval stage that engages in host seeking, a process whereby the infective larvae use sensory cues to search for hosts. Host seeking is a complex behavior that involves multiple sensory modalities, including olfaction, gustation, thermosensation, and humidity sensation. As the initial step of the parasite-host interaction, host seeking could be a powerful target for preventative intervention. However, host-seeking behavior remains poorly understood. Here we review what is currently known about the host-seeking behaviors of different parasitic nematodes, including insect-parasitic nematodes, mammalian-parasitic nematodes, and plant-parasitic nematodes. We also discuss the neural bases of these behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. A novel gene of Kalanchoe daigremontiana confers plant drought resistance.

    Science.gov (United States)

    Wang, Li; Zhu, Chen; Jin, Lin; Xiao, Aihua; Duan, Jie; Ma, Luyi

    2018-02-07

    Kalanchoe (K.) daigremontiana is important for studying asexual reproduction under different environmental conditions. Here, we describe a novel KdNOVEL41 (KdN41) gene that may confer drought resistance and could thereby affect K. daigremontiana development. The detected subcellular localization of a KdN41/Yellow Fluorescent Protein (YFP) fusion protein was in the nucleus and cell membrane. Drought, salt, and heat stress treatment in tobacco plants containing the KdN41 gene promoter driving β-glucuronidase (GUS) gene transcription revealed that only drought stress triggered strong GUS staining in the vascular tissues. Overexpression (OE) of the KdN41 gene conferred improved drought resistance in tobacco plants compared to wild-type and transformed with empty vector plants by inducing higher antioxidant enzyme activities, decreasing cell membrane damage, increasing abscisic acid (ABA) content, causing reinforced drought resistance related gene expression profiles. The 3,3'-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining results also showed less relative oxygen species (ROS) content in KdN41-overexpressing tobacco leaf during drought stress. Surprisingly, by re-watering after drought stress, KdN41-overexpressing tobacco showed earlier flowering. Overall, the KdN41 gene plays roles in ROS scavenging and osmotic damage reduction to improve tobacco drought resistance, which may increase our understanding of the molecular network involved in developmental manipulation under drought stress in K. daigremontiana.

  7. Clustering, haplotype diversity and locations of MIC-3: a unique root-specific defense-related gene family in upland cotton (Gossypium hirsutum L.)

    Science.gov (United States)

    MIC-3-related genes of cotton (Gossypium spp.) were identified and shown to have root-specific expression, associated with pathogen defense-related function and specifically increased expression in root-knot nematode (RKN) resistant plants after nematode infection. Here we cloned and sequenced MIC-...

  8. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

    OpenAIRE

    Adelowo, Olawale O.; Fagade, Obasola E.; Agersø, Yvonne

    2014-01-01

    Introduction: This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Methodology: Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. Results: A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resista...

  9. Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland.

    Science.gov (United States)

    Lanz, Roland; Kuhnert, Peter; Boerlin, Patrick

    2003-01-02

    Antimicrobial susceptibility testing was performed on a total of 581 clinical Escherichia coli isolates from diarrhea and edema disease in pigs, from acute mastitis in dairy cattle, from urinary tract infections in dogs and cats, and from septicemia in laying hens collected in Switzerland between 1999 and 2001. Among the 16 antimicrobial agents tested, resistance was most frequent for sulfonamides, tetracycline, and streptomycin. Isolates from swine presented significantly more resistance than those from the other animal species. The distribution of the resistance determinants for sulfonamides, tetracycline, and streptomycin was assessed by hybridization and PCR in resistant isolates. Significant differences in the distribution of resistance determinants for tetracycline (tetA, tetB) and sulfonamides (sulII) were observed between the isolates from swine and those from the other species. Resistance to sulfonamides could not be explained by known resistance mechanisms in more than a quarter of the sulfonamide-resistant and sulfonamide-intermediate isolates from swine, dogs and cats. This finding suggests that one or several new resistance mechanisms for sulfonamides may be widespread among E. coli isolates from these animal species. The integrase gene (intI) from class I integrons was detected in a large proportion of resistant isolates in association with the sulI and aadA genes, thus demonstrating the importance of integrons in the epidemiology of resistance in clinical E. coli isolates from animals.

  10. Comparative mapping of powdery mildew resistance gene Pm21 and functional characterization of resistance-related genes in wheat.

    Science.gov (United States)

    He, Huagang; Zhu, Shanying; Jiang, Zhengning; Ji, Yaoyong; Wang, Feng; Zhao, Renhui; Bie, Tongde

    2016-04-01

    The powdery mildew resistance gene Pm21 was physically and comparatively mapped by newly developed markers. Seven candidate genes were verified to be required for Pm21 -mediated resistance to wheat powdery mildew. Pm21, a gene derived from wheat wild relative Dasypyrum villosum, has been transferred into common wheat and widely utilized in wheat resistance breeding for powdery mildew. Previously, Pm21 has been located to the bin FL0.45-0.58 of 6VS by using deletion stocks. However, its fine mapping is still a hard work. In the present study, 30 gene-derived 6VS-specific markers were obtained based on the collinearity among genomes of Brachypodium distachyon, Oryza and Triticeae, and then physically and comparatively mapped in the bin FL0.45-0.58 and its nearby chromosome region. According to the maps, the bin FL0.45-0.58 carrying Pm21 was closely flanked by the markers 6VS-03 and 6VS-23, which further narrowed the orthologous regions to 1.06 Mb in Brachypodium and 1.38 Mb in rice, respectively. Among the conserved genes shared by Brachypodium and rice, four serine/threonine protein kinase genes (DvMPK1, DvMLPK, DvUPK and DvPSYR1), one protein phosphatase gene (DvPP2C) and two transcription factor genes (DvGATA and DvWHY) were confirmed to be required for Pm21-mediated resistance to wheat powdery mildew by barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) and transcriptional pattern analyses. In summary, this study gives new insights into the genetic basis of the Pm21 locus and the disease resistance pathways mediated by Pm21.

  11. Occurrence and Distribution of Antibiotic-resistant Bacteria and Transfer of Resistance Genes in Lake Taihu

    Science.gov (United States)

    Yin, Qian; Yue, Dongmei; Peng, Yuke; Liu, Ying; Xiao, Lin

    2013-01-01

    The overuse of antibiotics has accelerated antibiotic resistance in the natural environment, especially fresh water, generating a potential risk for public health around the world. In this study, antibiotic resistance in Lake Taihu was investigated and this was the first thorough data obtained through culture-dependent methods. High percentages of resistance to streptomycin and ampicillin among bacterial isolates were detected, followed by tetracycline and chloramphenicol. Especially high levels of ampicillin resistance in the western and northern regions were illustrated. Bacterial identification of the isolates selected for further study indicated the prevalence of some opportunistic pathogens and 62.0% of the 78 isolates exhibited multiple antibiotic resistance. The presence of ESBLs genes was in the following sequence: blaTEM > blaSHV > blaCTMX and 38.5% of the isolates had a class I integrase gene. Of all tested strains, 80.8% were able to transfer antibiotic resistance through conjugation. We also concluded that some new families of human-associated ESBLs and AmpC genes can be found in natural environmental isolates. The prevalence of antibiotic resistance and the dissemination of transferable antibiotic resistance in bacterial isolates (especially in opportunistic pathogens) was alarming and clearly indicated the urgency of realizing the health risks of antibiotic resistance to human and animal populations who are dependent on Lake Taihu for water consumption. PMID:24240317

  12. Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam.

    Science.gov (United States)

    Lien, La Thi Quynh; Lan, Pham Thi; Chuc, Nguyen Thi Kim; Hoa, Nguyen Quynh; Nhung, Pham Hong; Thoa, Nguyen Thi Minh; Diwan, Vishal; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia

    2017-06-29

    The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the bla TEM gene being more common than bla CTX-M . Co-harbouring of the bla CTX-M , bla TEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

  13. Antimicrobial resistance and prevalence of resistance genes of obligate anaerobes isolated from periodontal abscesses.

    Science.gov (United States)

    Xie, Yi; Chen, Jiazhen; He, Junlin; Miao, Xinyu; Xu, Meng; Wu, Xingwen; Xu, Beiyun; Yu, Liying; Zhang, Wenhong

    2014-02-01

    This study attempts to determine the antimicrobial resistance profiles of obligate anaerobic bacteria that were isolated from a periodontal abscess and to evaluate the prevalence of resistance genes in these bacteria. Forty-one periodontal abscess samples were cultivated on selective and non-selective culture media to isolate the oral anaerobes. Their antibiotic susceptibilities to clindamycin, doxycycline, amoxicillin, imipenem, cefradine, cefixime, roxithromycin, and metronidazole were determined using the agar dilution method, and polymerase chain reaction assays were performed to detect the presence of the ermF, tetQ, nim, and cfxA drug resistance genes. A total of 60 different bacterial colonies was isolated and identified. All of the isolates were sensitive to imipenem. Of the strains, 6.7%, 13.3%, 16.7%, and 25% were resistant to doxycycline, metronidazole, cefixime, and amoxicillin, respectively. The resistance rate for both clindamycin and roxithromycin was 31.7%. Approximately 60.7% of the strains had the ermF gene, and 53.3% of the amoxicillin-resistant strains were found to have the cfxA gene. Two nim genes that were found in eight metronidazole-resistant strains were identified as nimB. In the present study, the Prevotella species are the most frequently isolated obligate anaerobes from periodontal abscesses. The current results show their alarmingly high resistance rate against clindamycin and roxithromycin; thus, the use of these antibiotics is unacceptable for the empirical therapy of periodontal abscesses. A brief prevalence of four resistance genes in the anaerobic bacteria that were isolated was also demonstrated.

  14. Effects of Endobacterium (Stenotrophomonas maltophilia on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus and Pine Wilt Disease

    Directory of Open Access Journals (Sweden)

    Long-Xi He

    2016-05-01

    Full Text Available Pine wilt disease (PWD caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus, is responsible for devastating epidemics in pine trees in Asia and Europe. Recent studies showed that bacteria carried by the PWN might be involved in PWD. However, the molecular mechanism of the interaction between bacteria and the PWN remained unclear. Now that the whole genome of B. xylophilus (Bursaphelenchus xylophilus is published, transcriptome analysis is a unique method to study the role played by bacteria in PWN. In this study, the transcriptome of aseptic B. xylophilus, B. xylophilus treated with endobacterium (Stenotrophomonas maltophilia NSPmBx03 and fungus B. xylophilus were sequenced. We found that 61 genes were up-regulated and 830 were down-regulated in B. xylophilus after treatment with the endobacterium; 178 genes were up-regulated and 1122 were down-regulated in fungus B. xylophilus compared with aseptic B. xylophilus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to study the significantly changed biological functions and pathways for these differentially expressed genes. Many pathogenesis-related genes, including glutathinone S-transferase, pectate lyase, ATP-binding cassette transporter and cytochrome P450, were up-regulated after B. xylophilus were treated with the endobacterium. In addition, we found that bacteria enhanced the virulence of PWN. These findings indicate that endobacteria might play an important role in the development and virulence of PWN and will improve our understanding of the regulatory mechanisms involved in the interaction between bacteria and the PWN.

  15. Effects of Endobacterium (Stenotrophomonas maltophilia) on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus) and Pine Wilt Disease

    Science.gov (United States)

    He, Long-Xi; Wu, Xiao-Qin; Xue, Qi; Qiu, Xiu-Wen

    2016-01-01

    Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is responsible for devastating epidemics in pine trees in Asia and Europe. Recent studies showed that bacteria carried by the PWN might be involved in PWD. However, the molecular mechanism of the interaction between bacteria and the PWN remained unclear. Now that the whole genome of B. xylophilus (Bursaphelenchus xylophilus) is published, transcriptome analysis is a unique method to study the role played by bacteria in PWN. In this study, the transcriptome of aseptic B. xylophilus, B. xylophilus treated with endobacterium (Stenotrophomonas maltophilia NSPmBx03) and fungus B. xylophilus were sequenced. We found that 61 genes were up-regulated and 830 were down-regulated in B. xylophilus after treatment with the endobacterium; 178 genes were up-regulated and 1122 were down-regulated in fungus B. xylophilus compared with aseptic B. xylophilus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to study the significantly changed biological functions and pathways for these differentially expressed genes. Many pathogenesis-related genes, including glutathinone S-transferase, pectate lyase, ATP-binding cassette transporter and cytochrome P450, were up-regulated after B. xylophilus were treated with the endobacterium. In addition, we found that bacteria enhanced the virulence of PWN. These findings indicate that endobacteria might play an important role in the development and virulence of PWN and will improve our understanding of the regulatory mechanisms involved in the interaction between bacteria and the PWN. PMID:27231904

  16. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria.

    Science.gov (United States)

    Adelowo, Olawale O; Fagade, Obasola E; Agersø, Yvonne

    2014-09-12

    This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resistance was: tetracycline 81%, sulphamethoxazole 67%, streptomycin 56%, trimethoprim 47 %, ciprofloxacin 42%, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), strB (61%), catA1 (25%), cmlA1 (13%), tetA (21%) and tetB (17%). Class 1 and 2 integrons were found in five (14%) and six (17%) isolates, respectively, while one isolate was positive for both classes of integrons. Seven out of eight isolates with resistance to ciprofloxacin and MIC ≤ 32 mg/L to nalidixic acid contained qnrS genes. Our findings provided additional evidence that the poultry production environment in Nigeria represents an important reservoir of antibiotic resistance genes such as qnrS that may spread from livestock production farms to human populations via manure and water.

  17. High chlorpyrifos resistance in Culex pipiens mosquitoes: strong synergy between resistance genes

    Science.gov (United States)

    Alout, H; Labbé, P; Berthomieu, A; Makoundou, P; Fort, P; Pasteur, N; Weill, M

    2016-01-01

    We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l−1 and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1R allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1R and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1V or the duplicated ace-1D allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects. PMID:26463842

  18. Spread of tetracycline resistance genes at a conventional dairy farm

    Directory of Open Access Journals (Sweden)

    Martina eKyselkova

    2015-05-01

    Full Text Available The use of antibiotics in animal husbandry contributes to the worldwide problem of increasing antibiotic resistance in animal and human pathogens. Intensive animal production is considered an important source of antibiotic resistance genes released to the environment, while the contribution of smaller farms remains to be evaluated. Here we monitor the spread of tetracycline resistance (TC-r genes at a middle-size conventional dairy farm, where chlortetracycline (CTC, as intrauterine suppository is prophylactically used after each calving. Our study has shown that animals at the farm acquired the TC-r genes in their early age (1-2 weeks, likely due to colonization with TC-resistant bacteria from their mothers and/or the farm environment. The relative abundance of the TC-r genes tet(W, tet(Q and tet(M in fresh excrements of calves was about 1-2 orders of magnitude higher compared to heifers and dairy cows, possibly due to the presence of antibiotic residues in milk fed to calves. The occurrence and abundance of TC-r genes in fresh excrements of heifers and adult cows remained unaffected by intrauterine CTC applications, with tet(O, tet(Q and tet(W representing a ‘core TC-resistome’ of the farm, and tet(A, tet(M, tet(Y and tet(X occurring occasionally. The genes tet(A, tet(M, tet(Y and tet(X were shown to be respectively harbored by Shigella, Lactobacillus and Clostridium, Acinetobacter, and Wautersiella. Soil in the farm proximity, as well as field soil to which manure from the farm was applied, was contaminated with TC-r genes occurring in the farm, and some of the TC-r genes persisted in the field over 3 months following the manure application. Concluding, our study shows that antibiotic resistance genes may be a stable part of the intestinal metagenome of cattle even if antibiotics are not used for growth stimulation, and that smaller dairy farms may also contribute to environmental pollution with antibiotic resistance genes.

  19. Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

    Directory of Open Access Journals (Sweden)

    Masayoshi Hashimoto

    2016-10-01

    Full Text Available The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species.

  20. Bacterial metal resistance genes and metal bioavailability in contaminated sediments

    International Nuclear Information System (INIS)

    Roosa, Stéphanie; Wattiez, Ruddy; Prygiel, Emilie; Lesven, Ludovic; Billon, Gabriel; Gillan, David C.

    2014-01-01

    In bacteria a metal may be defined as bioavailable if it crosses the cytoplasmic membrane to reach the cytoplasm. Once inside the cell, specific metal resistance systems may be triggered. In this research, specific metal resistance genes were used to estimate metal bioavailability in sediment microbial communities. Gene levels were measured by quantitative PCR and correlated to metals in sediments using five different protocols to estimate dissolved, particle-adsorbed and occluded metals. The best correlations were obtained with czcA (a Cd/Zn/Co efflux pump) and Cd/Zn adsorbed or occluded in particles. Only adsorbed Co was correlated to czcA levels. We concluded that the measurement of czcA gene levels by quantitative PCR is a promising tool which may complement the classical approaches used to estimate Cd/Zn/Co bioavailability in sediment compartments. - Highlights: • Metal resistance genes were used to estimate metal bioavailability in sediments. • Gene levels were correlated to metals using 5 different metal extraction protocols. • CzcA gene levels determined by quantitative PCR is a promising tool for Cd/Zn/Co. - Capsule Bacterial czcA is a potential biomarker of Cd, Zn and Co bioavailability in aquatic sediments as shown by quantitative PCR and sequential metal extraction

  1. Sponge Microbiota are a Reservoir of Functional Antibiotic Resistance Genes

    DEFF Research Database (Denmark)

    Versluis, Dennis; de Evgrafov, Mari Cristina Rodriguez; Sommer, Morten Otto Alexander

    2016-01-01

    examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional...... resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis, and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n = 6), gentamicin (n = 1), amikacin (n = 7), trimethoprim (n = 17), chloramphenicol (n = 1), rifampicin (n = 2) and ampicillin (n = 3......-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance...

  2. Tagging of resistance gene(s) to rhizomania disease in sugar beet ...

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... plasmodiophoride-like fungus, Polymyxa betae Keskin. (1964) (Tamada and Richard, 1992). Source of resistance to rhizomania were found in Holly sugar beet company source (Lewellen, 1987). Resistance in Holly is simply inherited by a single dominant gene(Rz1). (Lewellen et al., 1987; Scholten et al., ...

  3. Tagging of resistance gene(s) to rhizomania disease in sugar beet ...

    African Journals Online (AJOL)

    The rhizomania disease is one of the most important diseases in Iran and some other parts of the world which potentially could play a role in decreasing sugar yield in fields. One approach to combat with this disease is the use of resistance varieties. This varieties have been identified which are having resistance genes to ...

  4. Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in 'Thatcher' Wheat.

    Science.gov (United States)

    Hiebert, Colin W; Kolmer, James A; McCartney, Curt A; Briggs, Jordan; Fetch, Tom; Bariana, Harbans; Choulet, Frederic; Rouse, Matthew N; Spielmeyer, Wolfgang

    2016-01-01

    Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. 'Thatcher' wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in 'Thatcher' and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for 'Thatcher'-derived APR in several environments and this resistance was enhanced in the presence of Lr34.

  5. Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in ‘Thatcher’ Wheat

    Science.gov (United States)

    Hiebert, Colin W.; Kolmer, James A.; McCartney, Curt A.; Briggs, Jordan; Fetch, Tom; Bariana, Harbans; Choulet, Frederic; Rouse, Matthew N.; Spielmeyer, Wolfgang

    2016-01-01

    Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. ‘Thatcher’ wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in ‘Thatcher’ and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for ‘Thatcher’-derived APR in several environments and this resistance was enhanced in the presence of Lr34. PMID:27309724

  6. Use of the induced gene-expression in the soil nematode Caenorhabditis elegans as a biomonitor; Nutzung der induzierbaren Genexpression des Nematoden Caenorhabditis elegans als Biomonitor

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, R.; Reichert, K.; Achazi, R. [Freie Univ. Berlin (Germany). Inst. fuer Biologie - Oekotoxikologie und Biochemie

    2002-07-01

    The soil nematode Caenorhabditis elegans is one of the simplest animals having the status of a laboratory model. Its already completely sequenced genome contains the remarkable number of 80 cytochrome P450 genes (CYP) and many further genes coding for enzymes involved in biotransformation. In order to study xenobiotically induced gene expression in C. elegans, liquid cultures were exposed to different, well-known xenobiotic inducers. The mRNA expression was detected by two different types of DNA arrays and semi-quantitative RT-PCR. {beta}-naphthoflavone, PCB52 and lansoprazol were the most active and, in particular, induced almost all CYP35 isoforms strongly. In conclusion, the xenobiotic dependent gene expression of C. elegans is a useful tool to reveal defense mechanisms against potential damaging substances as well as for developing a biomonitoring system. (orig.) [German] Der Bodennematode Caenorhabditis elegans gilt als das einfachste mehrzellige Tier mit dem Status eines Labormodels. Basierend auf seinem entschluesselten Genom konnte die bemerkenswerte Zahl von 80 Cytochrom P450 Genen (CYP) und eine Vielzahl weiterer Gene, welche fuer Enzyme der Biotransformation kodieren, identifiziert werden. Die differentielle Genexpression von C. elegans nach Schadstoffzugabe wurde in Fluessigkulturen mit 18 Xenobiotika aus unterschiedlichen Schadstoffgruppen untersucht. Anschliessend wurde die mRNA Expression mit DNA Arrays und semi-quantitativer RT-PCR bestimmt. {beta}-Naphthoflavone, PCB52 and Lansoprazol erwiesen sich dabei als die wirksamsten Induktoren und konnten unter anderen alle CYP 35 Isoformen stark induzieren. Mit diesen Untersuchungen konnte gezeigt werden, dass die schadstoffinduzierte Genexpression in C. elegans ein adaequates System ist, um sowohl Detoxifikationsmechanismen zu untersuchen als auch ein Biomonitorscreening aufzubauen. (orig.)

  7. Mi-1.2, an R gene for aphid resistance in tomato, has direct negative effects on a zoophytophagous biocontrol agent, Orius insidiosus.

    Science.gov (United States)

    Pallipparambil, Godshen R; Sayler, Ronald J; Shapiro, Jeffrey P; Thomas, Jean M G; Kring, Timothy J; Goggin, Fiona L

    2015-02-01

    Mi-1.2 is a single dominant gene in tomato that confers race-specific resistance against certain phloem-feeding herbivores including aphids, whiteflies, psyllids, and root-knot nematodes. Few prior studies have considered the potential non-target effects of race-specific resistance genes (R genes), and this paper evaluates the compatibility of Mi-mediated resistance in tomato with a beneficial zoophytophagous predator, Orius insidiosus (Say). In addition to preying on aphids and other pests, this piercing-sucking insect also feeds from the xylem, epidermis, and/or mesophyll, and oviposits within plant tissues. Comparison of O. insidiosus confined to isogenic tomato plants with and without Mi-1.2 revealed that immatures of O. insidiosus had lower survival on resistant plants even when the immatures were provisioned with prey that did not feed on the host plant. Molecular gut content analysis confirmed that adults and immatures of O. insidiosus feed on both resistant (Mi-1.2+) and susceptible (Mi-1.2-) genotypes, and bioassays suggest that resistance does not affect oviposition rates, plant sampling, or prey acceptance by O. insidiosus adults. These results demonstrate a direct negative impact of R-gene-mediated host plant resistance on a non-target beneficial species, and reveal that Mi-mediated resistance can impact organisms that do not feed on phloem sap. Through laser capture microdissection and RT-PCR, Mi-1.2 transcripts were detected in the epidermis and mesophyll as well as the phloem of tomato plants, consistent with our observations that Mi-mediated resistance is active outside the phloem. These results suggest that the mode of action and potential ecological impacts of Mi-mediated resistance are broader than previously assumed. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. The development of anthelmintic resistance with best practice control of nematodes on commercial sheep farms in the UK.

    Science.gov (United States)

    Learmount, Jane; Stephens, Nathalie; Boughtflower, Valerie; Barrecheguren, Alba; Rickell, Kayleigh

    2016-10-15

    Antimicrobial resistance threatens the effective prevention and treatment of an ever-increasing range of infections. The widespread development of anthelmintic resistance is a major global issue affecting the effective control of parasite diseases in grazing livestock production. Sustainable control strategies that reduce dependence on antimicrobials have the potential to slow the further development of resistance but there is little data on the effect of control strategies on resistance development in the field. This report documents a study undertaken to measure the temporal effect of the UK sustainable control of parasites in sheep (SCOPS) guidelines on the development of anthelmintic resistance. Farms carrying out SCOPS or traditional worm control (TRADITIONAL) were tested for resistance to the benzimidazole and imidazothiazole anthelmintics in vitro using a discriminating dose (dd) larval development test (LDT) in year 1 and then 7 years later. In years 5 and 7, resistance was also measured using a dose-response LDT assay. There was a significant increase in Teladorsagia survivors at the benzimidazole dd assay between year 1 and year 7 for both treatment groups, but the increase in survivors was greater for the farms carrying out their traditional worm control compared to the SCOPS farms. There was also a significant difference between benzimidazole dd results generated across years for Trichostrongylus, but the year and treatment interaction was not significant. Only one of the farm Teladorsagia populations had survivors in the imidazothiazole dd assay in years 1 and 7 and none of the Trichostrongylus populations survived in year 1 compared to isolates from three of the farms in year 7. Dose-response data showed a significant effect for time for both the benzimidazole and imidazothiazole anthelmintics and the increase was again significantly higher for the Teladorsagia populations in the TRADITIONAL group compared to the SCOPS group. This data suggests an

  9. Resistance-related gene transcription and antioxidant enzyme ...

    African Journals Online (AJOL)

    The two tobacco relatives of Nicotiana alata and Nicotiana longiflora display a high level of resistance against Colletotrichum nicotianae and the two genes NTF6 and NtPAL related to pathogen defense transcription were higher in N. alata and N. longiflora than the commercial cv. K326. Inoculation with C. nicotianae ...

  10. Antibiotic resistance and ndvB gene expression among biofilm ...

    African Journals Online (AJOL)

    A novel antibiotic resistant mechanism among biofilms is glucan-mediated sequestration in which ndvB gene encodes a glucosyltransferase involved in the formation of this glucans. We studied the biofilm formation and antibiotic susceptibility pattern of P. aeruginosa isolated from clinical samples, and measured the ...

  11. Gene pyramiding as a Bt resistance management strategy: How ...

    African Journals Online (AJOL)

    Reports on the emergence of insect resistance to Bacillus thuringiensis delta endotoxins have raised doubts on the sustainability of Bt-toxin based pest management technologies. Corporate industry has responded to this challenge with innovations that include gene pyramiding among others. Pyramiding entails stacking ...

  12. Prevalence, antibiotic-resistance properties and enterotoxin gene ...

    African Journals Online (AJOL)

    milk-based infant foods in Iran, represent an important public health issue which should be considered ... Keywords: Prevalence, Bacillus cereus, Antibiotic resistance, Enterotoxigenic genes, Milk-based infant food. Tropical Journal of Pharmaceutical Research is indexed by Science ..... and cereals collected in Korea.

  13. Spatial patterns of Antimicrobial Resistance Genes in Danish Pig Farms

    DEFF Research Database (Denmark)

    Birkegård, Anna Camilla; Ersbøll, A. K.; Hisham Beshara Halasa, Tariq

    2016-01-01

    antimicrobial resistance genes, ermB, ermF, sulI, sulII, tet(M), tet(O) and tet(W), was quantified by a high-throughput qPCR. It was evaluated whether the sample method resulted in a study population representative of Danish pig farms with finishers where it was found that the study population was biased...

  14. Molecular Detection of Virulence Genes and Antibiotic Resistance ...

    African Journals Online (AJOL)

    Escherichia coli O157:H7 is an important food-borne pathogen that can cause diarrhea, haemorrhagic colitis and haemolytic uremic syndrome. This study was conducted to investigate the prevalence, virulence genes and antibiotic resistance patterns of E. coli O157:H7 in raw beef meat sold in Abeokuta, South west Nigeria ...

  15. Genes co-regulated with LBD16 in nematode feeding sites inferred from in silico analysis show similarities to regulatory circuits mediated by the auxin/cytokinin balance in Arabidopsis.

    Science.gov (United States)

    Cabrera, Javier; Fenoll, Carmen; Escobar, Carolina

    2015-01-01

    Plant endoparasitic nematodes, root-knot and cyst nematodes (RKNs and CNs) induce within the root vascular cylinder transfer cells used for nourishing, termed giant cells (GCs) and syncytia. Understanding the molecular mechanisms behind this process is essential to develop tools for nematode control. Based on the crucial role in gall development of LBD16, also a key component of the auxin pathway leading to the divisions in the xylem pole pericycle during lateral root (LR) formation, we investigated genes co-regulated with LBD16 in different transcriptomes and analyzed their similarities and differences with those of RKNs and CNs feeding sites (FS). This analysis confirmed LBD16 and its co-regulated genes, integrated in signaling cascades mediated by auxins during LR and callus formation, as a particular feature of RKN-FS distinct to CNs. However, LBD16, and its positively co-regulated genes, were repressed in syncytia, suggesting a selective down- regulation of the LBD16 auxin mediated pathways in CNs-FS. Interestingly, cytokinin-induced genes are enriched in syncytia and we encountered similarities between the transcriptome of shoot regeneration from callus, modulated by cytokinins, and that of syncytia. These findings establish differences in the regulatory networks leading to both FS formation, probably modulated by the auxin/cytokinin balance.

  16. Putative resistance genes in the CitEST database

    Directory of Open Access Journals (Sweden)

    Simone Guidetti-Gonzalez

    2007-01-01

    Full Text Available Disease resistance in plants is usually associated with the activation of a wide variety of defense responses to prevent pathogen replication and/or movement. The ability of the host plant to recognize the pathogen and to activate defense responses is regulated by direct or indirect interaction between the products of plant resistance (R and pathogen avirulence (Avr genes. Attempted infection of plants by avirulent pathogens elicits a battery of defenses often followed by the collapse of the challenged host cells. Localized host cell death may help to prevent the pathogen from spreading to uninfected tissues, known as hypersensitive response (HR. When either the plant or the pathogen lacks its cognate gene, activation of the plant’s defense responses fails to occur or is delayed and does not prevent pathogen colonization. In the CitEST database, we identified 1,300 reads related to R genes in Citrus which have been reported in other plant species. These reads were translated in silico, and alignments of their amino acid sequences revealed the presence of characteristic domains and motifs that are specific to R gene classes. The description of the reads identified suggests that they function as resistance genes in citrus.

  17. Identification of antimicrobial resistance genes in multidrug-resistant clinical Bacteroides fragilis isolates by whole genome shotgun sequencing

    DEFF Research Database (Denmark)

    Sydenham, Thomas Vognbjerg; Sóki, József; Hasman, Henrik

    2015-01-01

    Bacteroides fragilis constitutes the most frequent anaerobic bacterium causing bacteremia in humans. The genetic background for antimicrobial resistance in B. fragilis is diverse with some genes requiring insertion sequence (IS) elements inserted upstream for increased expression. To evaluate whole...... genome shotgun sequencing as a method for predicting antimicrobial resistance properties, one meropenem resistant and five multidrug-resistant blood culture isolates were sequenced and antimicrobial resistance genes and IS elements identified using ResFinder 2.1 (http...

  18. A phylogenetic framework for root lesion nematodes of the genus Pratylenchus (Nematoda): Evidence from 18S and D2-D3 expansion segments of 28S ribosomal RNA genes and morphological characters.

    Science.gov (United States)

    Subbotin, Sergei A; Ragsdale, Erik J; Mullens, Teresa; Roberts, Philip A; Mundo-Ocampo, Manuel; Baldwin, James G

    2008-08-01

    The root lesion nematodes of the genus Pratylenchus Filipjev, 1936 are migratory endoparasites of plant roots, considered among the most widespread and important nematode parasites in a variety of crops. We obtained gene sequences from the D2 and D3 expansion segments of 28S rRNA partial and 18S rRNA from 31 populations belonging to 11 valid and two unidentified species of root lesion nematodes and five outgroup taxa. These datasets were analyzed using maximum parsimony and Bayesian inference. The alignments were generated using the secondary structure models for these molecules and analyzed with Bayesian inference under the standard models and the complex model, considering helices under the doublet model and loops and bulges under the general time reversible model. The phylogenetic informativeness of morphological characters is tested by reconstruction of their histories on rRNA based trees using parallel parsimony and Bayesian approaches. Phylogenetic and sequence analyses of the 28S D2-D3 dataset with 145 accessions for 28 species and 18S dataset with 68 accessions for 15 species confirmed among large numbers of geographical diverse isolates that most classical morphospecies are monophyletic. Phylogenetic analyses revealed at least six distinct major clades of examined Pratylenchus species and these clades are generally congruent with those defined by characters derived from lip patterns, numbers of lip annules, and spermatheca shape. Morphological results suggest the need for sophisticated character discovery and analysis for morphology based phylogenetics in nematodes.

  19. Interspecific nematode signals regulate dispersal behavior.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2 of plant parasitic Meloidogyne spp. and infective juveniles (IJs of entomopathogenic nematodes (EPN, e.g., Steinernema feltiae. Regulation of dispersal behavior has not been thoroughly investigated for C. elegans or any other nematode species. Based on the fact that ascarosides regulate entry in dauer stage as well as multiple behaviors in C. elegans adults including mating, avoidance and aggregation, we hypothesized that ascarosides might also be involved in regulation of dispersal behavior in C. elegans and for other nematodes such as IJ of phylogenetically related EPNs.Liquid chromatography-mass spectrometry analysis of C. elegans dauer conditioned media, which shows strong dispersing activity, revealed four known ascarosides (ascr#2, ascr#3, ascr#8, icas#9. A synthetic blend of these ascarosides at physiologically relevant concentrations dispersed C. elegans dauer in the presence of food and also caused dispersion of IJs of S. feltiae and J2s of plant parasitic Meloidogyne spp. Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9 and C. elegans (ascr#2 dispersal blends. Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

  20. Anthropogenic antibiotic resistance genes mobilization to the polar regions.

    Science.gov (United States)

    Hernández, Jorge; González-Acuña, Daniel

    2016-01-01

    Anthropogenic influences in the southern polar region have been rare, but lately microorganisms associated with humans have reached Antarctica, possibly from military bases, fishing boats, scientific expeditions, and/or ship-borne tourism. Studies of seawater in areas of human intervention and proximal to fresh penguin feces revealed the presence of Escherichia coli strains least resistant to antibiotics in penguins, whereas E. coli from seawater elsewhere showed resistance to one or more of the following antibiotics: ampicillin, tetracycline, streptomycin, and trim-sulfa. In seawater samples, bacteria were found carrying extended-spectrum β-lactamase (ESBL)-type CTX-M genes in which multilocus sequencing typing (MLST) showed different sequence types (STs), previously reported in humans. In the Arctic, on the contrary, people have been present for a long time, and the presence of antibiotic resistance genes (ARGs) appears to be much more wide-spread than was previously reported. Studies of E coli from Arctic birds (Bering Strait) revealed reduced susceptibility to antibiotics, but one globally spreading clone of E. coli genotype O25b-ST131, carrying genes of ESBL-type CTX-M, was identified. In the few years between sample collections in the same area, differences in resistance pattern were observed, with E. coli from birds showing resistance to a maximum of five different antibiotics. Presence of resistance-type ESBLs (TEM, SHV, and CTX-M) in E. coli and Klebsiella pneumoniae was also confirmed by specified PCR methods. MLST revealed that those bacteria carried STs that connect them to previously described strains in humans. In conclusion, bacteria previously related to humans could be found in relatively pristine environments, and presently human-associated, antibiotic-resistant bacteria have reached a high global level of distribution that they are now found even in the polar regions.

  1. Functional study of the novel multidrug resistance gene HA117 and its comparison to multidrug resistance gene 1

    Directory of Open Access Journals (Sweden)

    Chen Tingfu

    2010-07-01

    Full Text Available Abstract Background The novel gene HA117 is a multidrug resistance (MDR gene expressed by all-trans retinoic acid-resistant HL-60 cells. In the present study, we compared the multidrug resistance of the HA117 with that of the classical multidrug resistance gene 1 (MDR1 in breast cancer cell line 4T1. Methods Transduction of the breast cancer cell line 4T1 with adenoviral vectors encoding the HA117 gene and the green fluorescence protein gene (GFP (Ad-GFP-HA117, the MDR1 and GFP (Ad-GFP-MDR1 or GFP (Ad-GFP was respectively carried out. The transduction efficiency and the multiplicity of infection (MOI were detected by fluorescence microscope and flow cytometry. The transcription of HA117 gene and MDR1 gene were detected by reverse transcription polymerase chain reaction (RT-PCR. Western blotting analysis was used to detect the expression of P-glycoprotein (P-gp but the expression of HA117 could not be analyzed as it is a novel gene and its antibody has not yet been synthesized. The drug-excretion activity of HA117 and MDR1 were determined by daunorubicin (DNR efflux assay. The drug sensitivities of 4T1/HA117 and 4T1/MDR1 to chemotherapeutic agents were detected by Methyl-Thiazolyl-Tetrazolium (MTT assay. Results The transducted efficiency of Ad-GFP-HA117 and Ad-GFP-MDR1 were 75%-80% when MOI was equal to 50. The transduction of Ad-GFP-HA117 and Ad-GFP-MDR1 could increase the expression of HA117 and MDR1. The drug resistance index to Adriamycin (ADM, vincristine (VCR, paclitaxel (Taxol and bleomycin (BLM increased to19.8050, 9.0663, 9.7245, 3.5650 respectively for 4T1/HA117 and 24.2236, 11.0480, 11.3741, 0.9630 respectively for 4T1/MDR1 as compared to the control cells. There were no significant differences in drug sensitivity between 4T1/HA117 and 4T1/MDR1 for the P-gp substrates (ADM, VCR and Taxol (P Conclusions These results confirm that HA117 is a strong MDR gene in both HL-60 and 4T1 cells. Furthermore, our results indicate that the MDR

  2. Polymorphisms in Plasmodium falciparum chloroquine resistance transporter and multidrug resistance 1 genes

    DEFF Research Database (Denmark)

    Venkatesan, Meera; Gadalla, Nahla B; Stepniewska, Kasia

    2014-01-01

    Adequate clinical and parasitologic cure by artemisinin combination therapies relies on the artemisinin component and the partner drug. Polymorphisms in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance 1 (pfmdr1) genes are associated...... with decreased sensitivity to amodiaquine and lumefantrine, but effects of these polymorphisms on therapeutic responses to artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) have not been clearly defined. Individual patient data from 31 clinical trials were harmonized and pooled by using standardized...

  3. Gastrointestinal nematode control practices on lowland sheep farms in Ireland with reference to selection for anthelmintic resistance

    Directory of Open Access Journals (Sweden)

    Patten Thomas

    2011-03-01

    Full Text Available Abstract Gastrointestinal parasitism is a widely recognised problem in sheep production, particularly for lambs. While anthelmintics have a pivotal role in controlling the effects of parasites, there is a paucity of data on how farmers use anthelmintics. A representative sample of Irish lowland farmers were surveyed regarding their parasite control practices and risk factors that may contribute to the development of anthelmintic resistance. Questionnaires were distributed to 166 lowland Irish sheep producers. The vast majority of respondents treated their sheep with anthelmintics. Lambs were the cohort treated most frequently, the majority of farmers followed a set programme as opposed to treating at sign of disease. A substantial proportion (61% administered four or more treatments to lambs in a 'normal' year. Departures from best practice in anthelmintic administration that would encourage the development of anthelmintic resistance were observed. In conclusion, in the light of anthelmintic resistance, there is a need for a greater awareness of the principles that underpin the sustainable use of anthelmintics and practices that preserve anthelmintic efficacy should be given a very high priority in the design of helminth control programmes on each farm. To this end, given that veterinary practitioners and agricultural advisors were considered to be the farmer's most popular information resource, the capacity of these professions to communicate information relating to best practice in parasite control should be targeted.

  4. Recombination Rate Heterogeneity within Arabidopsis Disease Resistance Genes.

    Science.gov (United States)

    Choi, Kyuha; Reinhard, Carsten; Serra, Heïdi; Ziolkowski, Piotr A; Underwood, Charles J; Zhao, Xiaohui; Hardcastle, Thomas J; Yelina, Nataliya E; Griffin, Catherine; Jackson, Matthew; Mézard, Christine; McVean, Gil; Copenhaver, Gregory P; Henderson, Ian R

    2016-07-01

    Meiotic crossover frequency varies extensively along chromosomes and is typically concentrated in hotspots. As recombination increases genetic diversity, hotspots are predicted to occur at immunity genes, where variation may be beneficial. A major component of plant immunity is recognition of pathogen Avirulence (Avr) effectors by resistance (R) genes that encode NBS-LRR domain proteins. Therefore, we sought to test whether NBS-LRR genes would overlap with meiotic crossover hotspots using experimental genetics in Arabidopsis thaliana. NBS-LRR genes tend to physically cluster in plant genomes; for example, in Arabidopsis most are located in large clusters on the south arms of chromosomes 1 and 5. We experimentally mapped 1,439 crossovers within these clusters and observed NBS-LRR gene associated hotspots, which were also detected as historical hotspots via analysis of linkage disequilibrium. However, we also observed NBS-LRR gene coldspots, which in some cases correlate with structural heterozygosity. To study recombination at the fine-scale we used high-throughput sequencing to analyze ~1,000 crossovers within the RESISTANCE TO ALBUGO CANDIDA1 (RAC1) R gene hotspot. This revealed elevated intragenic crossovers, overlapping nucleosome-occupied exons that encode the TIR, NBS and LRR domains. The highest RAC1 recombination frequency was promoter-proximal and overlapped CTT-repeat DNA sequence motifs, which have previously been associated with plant crossover hotspots. Additionally, we show a significant influence of natural genetic variation on NBS-LRR cluster recombination rates, using crosses between Arabidopsis ecotypes. In conclusion, we show that a subset of NBS-LRR genes are strong hotspots, whereas others are coldspots. This reveals a complex recombination landscape in Arabidopsis NBS-LRR genes, which we propose results from varying coevolutionary pressures exerted by host-pathogen relationships, and is influenced by structural heterozygosity.

  5. Multi drug resistance to cancer chemotherapy: Genes involved and blockers

    International Nuclear Information System (INIS)

    Sayed-Ahmed, Mohamed M.

    2007-01-01

    During the last three decades, important and considerable research efforts had been performed to investigate the mechanism through which cancer cells overcome the cytotoxic effects of a variety of chemotherapeutic drugs. Most of the previously published work has been focused on the resistance of tumor cells to those anticancer drugs of natural source. Multidrug resistance (MDR) is a cellular cross-resistance to a broad spectrum of natural products used in cancer chemotherapy and is believed to be the major cause of the therapeutic failures of the drugs belonging to different naturally obtained or semisynthetic groups including vinca alkaloids, taxans, epipodophyllotoxins and certain antibiotics. This phenomenon results from overexpression of four MDR genes and their corresponding proteins that act as membrane-bound ATP consuming pumps. These proteins mediate the efflux of many structurally and functionally unrelated anticancer drugs of natural source. MDR may be intrinsic or acquired following exposure to chemotherapy. The existence of intrinsically resistant tumor cell clone before and following chemotherapeutic treatment has been associated with a worse final outcome because of increased incidence of distant metasis. In view of irreplaceability of natural product anticancer drugs as effective chemotherapeutic agents, and in view of MDR as a major obstacle to successful chemotherapy, this review is aimed to highlight the genes involved in MDR, classical MDR blockers and gene therapy approaches to overcome MDR. (author)

  6. Mapping fusiform rust resistance genes within a complex mating design of loblolly pine

    Science.gov (United States)

    Tania Quesada; Marcio F.R. Resende Jr.; Patricio Munoz; Jill L. Wegrzyn; David B. Neale; Matias Kirst; Gary F. Peter; Salvador A. Gezan; C.Dana Nelson; John M. Davis

    2014-01-01

    Fusiform rust resistance can involve gene-for-gene interactions where resistance (Fr) genes in the host interact with corresponding avirulence genes in the pathogen, Cronartium quercuum f.sp. fusiforme (Cqf). Here, we identify trees with Fr genes in a loblolly pine population derived from a complex mating design challenged with two Cqf inocula (one gall and 10 gall...

  7. Spread of tetracycline resistance genes at a conventional dairy farm

    Czech Academy of Sciences Publication Activity Database

    Kyselková, Martina; Jirout, Jiří; Vrchotová, Naděžda; Schmitt, H.; Elhottová, Dana

    2015-01-01

    Roč. 6, may (2015), s. 536 ISSN 1664-302X R&D Projects: GA ČR GAP504/10/2077; GA MŠk(CZ) EE2.3.30.0032; GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 ; RVO:60077344 Keywords : antibiotic resistance spread * animal manure * cattle intestinal microflora * chlortetracycline * dairy cattle * dairy farm * heavy metals * tetracycline resistance genes Subject RIV: EI - Biotechnology ; Bionics; EE - Microbiology, Virology (BC-A) Impact factor: 4.165, year: 2015

  8. Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

    Science.gov (United States)

    The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

  9. Overexpression of SOS genes in ciprofloxacin resistant Escherichia coli mutants.

    Science.gov (United States)

    Pourahmad Jaktaji, Razieh; Pasand, Shirin

    2016-01-15

    Fluoroquinolones are important antibiotics for the treatment of urinary tract infections caused by Escherichia coli. Mutational studies have shown that ciprofloxacin, a member of fluoroquinolones induces SOS response and mutagenesis in pathogenic bacteria which in turn develop antibiotic resistance. However, inhibition of SOS response can increase recombination activity which in turn leads to genetic variation. The aim of this study was to measure 5 SOS genes expressions in nine E. coli mutants with different MICs for ciprofloxacin following exposure to ciprofloxacin. Gene expression was assessed by quantitative real time PCR. Gene alteration assessment was conducted by PCR amplification and DNA sequencing. Results showed that the expression of recA was increased in 5 mutants. This overexpression is not related to gene alteration, and enhances the expression of polB and umuCD genes encoding nonmutagenic and mutagenic polymerases, respectively. The direct relationship between the level of SOS expression and the level of resistance to ciprofloxacin was also indicated. It was concluded that novel therapeutic strategy that inhibits RecA activity would enhance the efficiency of common antibiotics against pathogenic bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    Science.gov (United States)

    Hong, Pei-Ying; Al-Jassim, Nada; Ansari, Mohd Ikram; Mackie, Roderick I.

    2013-01-01

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water. PMID:27029309

  11. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    KAUST Repository

    Hong, Pei-Ying; Aljassim, Nada I.; Ansari, Mohd Ikram; Mackie, Roderick

    2013-01-01

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  12. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Roderick I. Mackie

    2013-07-01

    Full Text Available Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  13. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    KAUST Repository

    Hong, Pei-Ying

    2013-07-31

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  14. Dissemination of antibiotic resistance genes from antibiotic producers to pathogens

    DEFF Research Database (Denmark)

    Jiang, Xinglin; Ellabaan, Mostafa M Hashim; Charusanti, Pep

    2017-01-01

    It has been hypothesized that some antibiotic resistance genes (ARGs) found in pathogenic bacteria derive from antibiotic-producing actinobacteria. Here we provide bioinformatic and experimental evidence supporting this hypothesis. We identify genes in proteobacteria, including some pathogens...... and experimentally test a 'carry-back' mechanism for the transfer, involving conjugative transfer of a carrier sequence from proteobacteria to actinobacteria, recombination of the carrier sequence with the actinobacterial ARG, followed by natural transformation of proteobacteria with the carrier-sandwiched ARG. Our...... results support the existence of ancient and, possibly, recent transfers of ARGs from antibiotic-producing actinobacteria to proteobacteria, and provide evidence for a defined mechanism....

  15. Transcriptome profiling and digital gene expression analysis of genes associated with salinity resistance in peanut

    Directory of Open Access Journals (Sweden)

    Jiongming Sui

    2018-03-01

    Full Text Available Background: Soil salinity can significantly reduce crop production, but the molecular mechanism of salinity tolerance in peanut is poorly understood. A mutant (S1 with higher salinity resistance than its mutagenic parent HY22 (S3 was obtained. Transcriptome sequencing and digital gene expression (DGE analysis were performed with leaves of S1 and S3 before and after plants were irrigated with 250 mM NaCl. Results: A total of 107,725 comprehensive transcripts were assembled into 67,738 unigenes using TIGR Gene Indices clustering tools (TGICL. All unigenes were searched against the euKaryotic Ortholog Groups (KOG, gene ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG databases, and these unigenes were assigned to 26 functional KOG categories, 56 GO terms, 32 KEGG groups, respectively. In total 112 differentially expressed genes (DEGs between S1 and S3 after salinity stress were screened, among them, 86 were responsive to salinity stress in S1 and/or S3. These 86 DEGs included genes that encoded the following kinds of proteins that are known to be involved in resistance to salinity stress: late embryogenesis abundant proteins (LEAs, major intrinsic proteins (MIPs or aquaporins, metallothioneins (MTs, lipid transfer protein (LTP, calcineurin B-like protein-interacting protein kinases (CIPKs, 9-cis-epoxycarotenoid dioxygenase (NCED and oleosins, etc. Of these 86 DEGs, 18 could not be matched with known proteins. Conclusion: The results from this study will be useful for further research on the mechanism of salinity resistance and will provide a useful gene resource for the variety breeding of salinity resistance in peanut. Keywords: Digital gene expression, Gene, Mutant, NaCl, Peanut (Arachis hypogaea L., RNA-seq, Salinity stress, Salinity tolerance, Soil salinity, Transcripts, Unigenes

  16. A novel resistance gene, lnu(H), conferring resistance to lincosamides in Riemerella anatipestifer CH-2.

    Science.gov (United States)

    Luo, Hong-Yan; Liu, Ma-Feng; Wang, Ming-Shu; Zhao, Xin-Xin; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Biville, Francis; Zou, Yuan-Feng; Jing, Bo; Cheng, An-Chun; Zhu, De-Kang

    2018-01-01

    The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 128 µg/mL. The G148_1775 gene of R. anatipestifer CH-2, designated lnu(H), encodes a 260-amino acid protein with ≤41% identity to other reported lincosamide nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24-lnu(H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu(H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu(H) gene. The transformant R. anatipestifer ATCC 11845 [lnu(H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu(H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2. Copyright © 2017. Published by Elsevier B.V.

  17. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

    DEFF Research Database (Denmark)

    Adelowo, Olawale O.; Fagade, Obasola E.; Agersø, Yvonne

    2014-01-01

    %, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), str...

  18. A SNARE-like protein and biotin are implicated in soybean cyst nematode virulence

    Science.gov (United States)

    Some phytoparasitic nematodes have the ability to infect and reproduce on plants that are normally considered resistant to nematode infection. Such nematodes are referred to as virulent and the mechanisms they use to evade or suppress host plant defenses are not well understood. Here, we report the ...

  19. Resistência de porta-enxertos para pessegueiro e ameixeira aos nematóides causadores de galhas (Meloidogyne spp. Resistance of rootstock for peach tree and plum to root-knot nematodes (Meloidogyne spp.

    Directory of Open Access Journals (Sweden)

    José Carlos Fachinello

    2000-03-01

    Full Text Available O trabalho foi realizado com o objetivo de comparar o comportamento de cinco diferentes porta-enxertos para frutas de caroço em frente a duas espécies de nematóides do gênero Meloidogyne (Meloidogyne javanica e Meloidogyne incognita. O cultivar GF 677 foi obtido a partir do cultivo in vitro e os demais porta-enxertos a partir de sementes. Aos dois meses, as plântulas foram repicadas e inoculadas com uma mistura de Meloidogyne javanica e M. incognita aos 30, 60 e 70 dias após o plantio em canteiros incorporando-se 0,2kg de solo altamente infestado com os nematóides ao redor de cada planta. Ao final do experimento, avaliaram-se o desenvolvimento das plantas e o grau de infecção de cada cultivar. O grau de resistência dos cultivares foi estimado a partir do índice de galhas, obtido através de uma escala de grau ou nota, a qual varia de 0 a 5, em função do número de galhas ou ootecas. Os resultados obtidos demonstraram que o cultivar Okinawa não apresentou galhas no sistema radicular e na análise de crescimento foi superior aos demais cultivares. Os cultivares R-15-2 e Aldrighi foram considerados resistentes aos fitonematóides por apresentarem pequeno número de galhas no sistema radicular. Já o cultivar GF 677 apresentou maior número de galhas no sistema radicular, chegando a 126 galhas/g de raiz.The work was carried out with the objective of comparing the response of five different stone fruit rootstocks to two nematode species (Meloidogyne javanica and Meloidogyne incognita. The cultivar GF677, which was obtained from in vitro cultivation and the others rootstocks, were obtained from seedlings. Two month old plants were transplanted and inoculated with a mixture of both nematode species at 30, 60, 70 days after planting, by incorporating 0.2kg of highly infested soil around each cultivar. The development of the roststocks were evaluated at the end of the experiment. Number of galls, ranging from 0 to 5 was used to score the

  20. Antimicrobial susceptibility and occurrence of resistance genes among Salmonella enterica serovar Weltevreden from different countries

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Lertworapreecha, M.; Evans, M.C.

    2003-01-01

    and gentamicin. All nine ampicillin-resistant isolates contained a sequence similar to the bla(TEM-1b) gene, one of the eight chloramphenicol-resistant isolates a sequence similar to the catA1 gene, all three neomycin-resistant isolates a sequence similar to the aphA-2 gene, 16 (73%) of the 22 streptomycin...... isolates were examined for susceptibility to antimicrobial agents, and resistant isolates were examined for the presence of selected resistance genes by PCR. Results: Only 48 (9.5%) of the isolates were resistant to one or more of the antimicrobial agents tested. A low frequency of resistance was found...

  1. Transcriptomic analysis of the rice white tip nematode, Aphelenchoides besseyi (Nematoda: Aphelenchoididae.

    Directory of Open Access Journals (Sweden)

    Feng Wang

    Full Text Available BACKGROUND: The rice white tip nematode Aphelenchoides besseyi, a devastating nematode whose genome has not been sequenced, is distributed widely throughout almost all the rice-growing regions of the world. The aims of the present study were to define the transcriptome of A. besseyi and to identify parasite-related, mortality-related or host resistance-overcoming genes in this nematode. METHODOLOGY AND PRINCIPAL FINDINGS: Using Solexa/Illumina sequencing, we profiled the transcriptome of mixed-stage populations of A. besseyi. A total of 51,270 transcripts without gaps were produced based on high-quality clean reads. Of all the A. besseyi transcripts, 9,132 KEGG Orthology assignments were annotated. Carbohydrate-active enzymes of glycoside hydrolases (GHs, glycosyltransferases (GTs, carbohydrate esterases (CEs and carbohydrate-binding modules (CBMs were identified. The presence of the A. besseyi GH45 cellulase gene was verified by in situ hybridization. Given that 13 unique A. besseyi potential effector genes were identified from 41 candidate effector homologs, further studies of these homologs are merited. Finally, comparative analyses were conducted between A. besseyi contigs and Caenorhabditis elegans genes to look for orthologs of RNAi phenotypes, neuropeptides and peptidases. CONCLUSIONS AND SIGNIFICANCE: The present results provide comprehensive insight into the genetic makeup of A. besseyi. Many of this species' genes are parasite related, nematode mortality-related or necessary to overcome host resistance. The generated transcriptome dataset of A. besseyi reported here lays the foundation for further studies of the molecular mechanisms related to parasitism and facilitates the development of new control strategies for this species.

  2. Evolution of resistance against CRISPR/Cas9 gene drive

    OpenAIRE

    Clark, Andrew; Unckless, Robert; Messer, Philipp

    2016-01-01

    CRISPR/Cas9 gene drive (CGD) promises to be a highly adaptable approach for spreading genetically engineered alleles throughout a species, even if those alleles impair reproductive success. CGD has been shown to be effective in laboratory crosses of insects, yet it remains unclear to what extent potential resistance mechanisms will affect the dynamics of this process in large natural populations. Here we develop a comprehensive population genetic framework for modeling CGD dynamics, which inc...

  3. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  4. Occurrence of antibiotic resistance and characterization of resistant genes and integrons in Enterobacteriaceae isolated from integrated fish farms south China

    Science.gov (United States)

    Su, Hao-Chang; Ying, Guang-Guo; Tao, Ran; Zhang, Rui-Quan; Fogarty, Lisa R.; Kolpin, Dana W.

    2011-01-01

    Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture.

  5. Sulfonamide-Resistant Bacteria and Their Resistance Genes in Soils Fertilized with Manures from Jiangsu Province, Southeastern China

    OpenAIRE

    Wang, Na; Yang, Xiaohong; Jiao, Shaojun; Zhang, Jun; Ye, Boping; Gao, Shixiang

    2014-01-01

    Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of a...

  6. Potent Nematicidal Activity and New Hybrid Metabolite Production by Disruption of a Cytochrome P450 Gene Involved in the Biosynthesis of Morphological Regulatory Arthrosporols in Nematode-Trapping Fungus Arthrobotrys oligospora.

    Science.gov (United States)

    Song, Tian-Yang; Xu, Zi-Fei; Chen, Yong-Hong; Ding, Qiu-Yan; Sun, Yu-Rong; Miao, Yang; Zhang, Ke-Qin; Niu, Xue-Mei

    2017-05-24

    Types of polyketide synthase-terpenoid synthase (PKS-TPS) hybrid metabolites, including arthrosporols with significant morphological regulatory activity, have been elucidated from nematode-trapping fungus Arthrobotrys oligospora. A previous study suggested that the gene cluster AOL_s00215 in A. oligospora was involved in the production of arthrosporols. Here, we report that disruption of one cytochrome P450 monooxygenase gene AOL_s00215g280 in the cluster resulted in significant phenotypic difference and much aerial hyphae. A further bioassay indicated that the mutant showed a dramatic decrease in the conidial formation but developed numerous traps and killed 85% nematodes within 6 h in contact with prey, in sharp contrast to the wild-type strain with no obvious response. Chemical investigation revealed huge accumulation of three new PKS-TPS epoxycyclohexone derivatives with different oxygenated patterns around the epoxycyclohexone moiety and the absence of arthrosporols in the cultural broth of the mutant ΔAOL_s00215g280. These findings suggested that a study on the biosynthetic pathway for morphological regulatory metabolites in nematode-trapping fungus would provide an efficient way to develop new fungal biocontrol agents.

  7. Identification of Gene Resistance to Avian InfluenzaVirus (Mx Gene among Wild Waterbirds

    Directory of Open Access Journals (Sweden)

    Dewi Elfidasari

    2013-04-01

    Full Text Available The Mx gene is an antiviral gene used to determine the resistance or the susceptibility to different types of viruses, including the Avian Influenza (AI virus subtype H5N1. The AI virus subtype H5N1 infection in chickens causes Mx gene polymorphism. The Mx+ gene shows resistant to the AIvirus subtype H5N1, whereas the Mx-gene shows signs of susceptible. The objective of thisresearch was to detect the Mxgene in wild aquatic birds using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP method with the primer pairs F2 and NE-R2/R and the RsaI restriction enzyme. DNA samples were obtained from eight species of wild waterbirds with positive and negative exposure to the AI virus subtype H5N1. DNA amplification results showed that the Mxgene in wild aquatic birds is found in a 100 bp fragment, which is the same as the Mx gene found in chickens. However, unlike chickens, the Mxgene in wild aquatic birds did not show any polymorphism. This study proves that Mx- based resistance to AI virus subtype H5N1 in different in wild birds than in chickens.

  8. Presence of antiseptic resistance genes in porcine methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Wong, T Z; Zhang, M; O'Donoghue, M; Boost, M

    2013-03-23

    Numerous studies have documented the presence of methicillin-resistant Staphylococcus aureus (MRSA) in meat-producing animals, which has led to concern about its spread into the community. Disinfectants play an important role in reduction of contamination in both animal husbandry and food-preparation, helping control spread of organisms from foodstuffs, including raw meat. Plasmid-borne antiseptic resistance (AR) genes increasing tolerance to several disinfectants have been reported in S. aureus of human origin (qacA/B and smr) and from bovine, equine, and caprine staphylococcal isolates (qacG, qacH, and qacJ). This study investigated the presence of AR genes in porcine MRSA isolates. Plasmid DNA from 100 MRSA ST9 strains isolated from pig carcasses was amplified for the presence of AR genes. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) to benzalkonium chloride (BC) and chlorhexidine gluconate (CHX) were determined in AR gene-positive isolates. qacG was present in 45 strains, eight of which also harbored smr. No strains carried qacA/B, qacH or qacJ. Presence of smr increased MICs to both BC and CHX and MBCs of CHX, but qacG presence only resulted in elevated MBC for CHX. This is the first report of AR genes from a porcine source. AR gene positivity has previously been associated with methicillin resistance and AR gene presence in these strains may increase their ability to persist in the environment. Improved implementation of hygiene measures during transportation and pre- and post-slaughter should be considered to prevent spread in the community. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost.

    Science.gov (United States)

    Han, Heping; Vila-Aiub, Martin M; Jalaludin, Adam; Yu, Qin; Powles, Stephen B

    2017-12-01

    A novel glyphosate resistance double point mutation (T102I/P106S, TIPS) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene has been recently identified for the first time only in the weed species Eleusine indica. Quantification of plant resistance cost associated with the TIPS and the often reported glyphosate resistance single P106S mutation was performed. A significant resistance cost (50% in seed number currency) associated with the homozygous TIPS but not the homozygous P106S EPSPS variant was identified in E. indica plants. The resistance cost associated with the TIPS mutation escalated to 85% in plants under resource competition with rice crops. The resistance cost was not detected in nonhomozygous TIPS plants denoting the recessive nature of the cost associated with the TIPS allele. An excess of 11-fold more shikimate and sixfold more quinate in the shikimate pathway was detected in TIPS plants in the absence of glyphosate treatment compared to wild type, whereas no changes in these compounds were observed in P106S plants when compared to wild type. TIPS plants show altered metabolite levels in several other metabolic pathways that may account for the expression of the observed resistance cost. © 2017 John Wiley & Sons Ltd.

  10. The wheat Lr34 multipathogen resistance gene confers resistance to anthracnose and rust in sorghum.

    Science.gov (United States)

    Schnippenkoetter, Wendelin; Lo, Clive; Liu, Guoquan; Dibley, Katherine; Chan, Wai Lung; White, Jodie; Milne, Ricky; Zwart, Alexander; Kwong, Eunjung; Keller, Beat; Godwin, Ian; Krattinger, Simon G; Lagudah, Evans

    2017-11-01

    The ability of the wheat Lr34 multipathogen resistance gene (Lr34res) to function across a wide taxonomic boundary was investigated in transgenic Sorghum bicolor. Increased resistance to sorghum rust and anthracnose disease symptoms following infection with the biotrophic pathogen Puccinia purpurea and the hemibiotroph Colletotrichum sublineolum, respectively, occurred in transgenic plants expressing the Lr34res ABC transporter. Transgenic sorghum lines that highly expressed the wheat Lr34res gene exhibited immunity to sorghum rust compared to the low-expressing single copy Lr34res genotype that conferred partial resistance. Pathogen-induced pigmentation mediated by flavonoid phytoalexins was evident on transgenic sorghum leaves following P. purpurea infection within 24-72 h, which paralleled Lr34res gene expression. Elevated expression of flavone synthase II, flavanone 4-reductase and dihydroflavonol reductase genes which control the biosynthesis of flavonoid phytoalexins characterized the highly expressing Lr34res transgenic lines 24-h post-inoculation with P. purpurea. Metabolite analysis of mesocotyls infected with C. sublineolum showed increased levels of 3-deoxyanthocyanidin metabolites were associated with Lr34res expression, concomitant with reduced symptoms of anthracnose. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  11. The bacterial community of entomophilic nematodes and host beetles.

    Science.gov (United States)

    Koneru, Sneha L; Salinas, Heilly; Flores, Gilberto E; Hong, Ray L

    2016-05-01

    Insects form the most species-rich lineage of Eukaryotes and each is a potential host for organisms from multiple phyla, including fungi, protozoa, mites, bacteria and nematodes. In particular, beetles are known to be associated with distinct bacterial communities and entomophilic nematodes. While entomopathogenic nematodes require symbiotic bacteria to kill and reproduce inside their insect hosts, the microbial ecology that facilitates other types of nematode-insect associations is largely unknown. To illuminate detailed patterns of the tritrophic beetle-nematode-bacteria relationship, we surveyed the nematode infestation profiles of scarab beetles in the greater Los Angeles area over a five-year period and found distinct nematode infestation patterns for certain beetle hosts. Over a single season, we characterized the bacterial communities of beetles and their associated nematodes using high-throughput sequencing of the 16S rRNA gene. We found significant differences in bacterial community composition among the five prevalent beetle host species, independent of geographical origin. Anaerobes Synergistaceae and sulphate-reducing Desulfovibrionaceae were most abundant in Amblonoxia beetles, while Enterobacteriaceae and Lachnospiraceae were common in Cyclocephala beetles. Unlike entomopathogenic nematodes that carry bacterial symbionts, insect-associated nematodes do not alter the beetles' native bacterial communities, nor do their microbiomes differ according to nematode or beetle host species. The conservation of Diplogastrid nematodes associations with Melolonthinae beetles and sulphate-reducing bacteria suggests a possible link between beetle-bacterial communities and their associated nematodes. Our results establish a starting point towards understanding the dynamic interactions between soil macroinvertebrates and their microbiota in a highly accessible urban environment. © 2016 John Wiley & Sons Ltd.

  12. Data mining and influential analysis of gene expression data for plant resistance gene identification in tomato (Solanum lycopersicum

    Directory of Open Access Journals (Sweden)

    Francisco Torres-Avilés

    2014-03-01

    Conclusion: Application of different statistical analyses to detect potential resistance genes reliably has shown to conduct interesting results that improve knowledge on molecular mechanisms of plant resistance to pathogens.

  13. [State-of-the-art status on airborne antibiotic resistant bacteria and antibiotic resistance genes].

    Science.gov (United States)

    Li, J; Yao, M S

    2018-04-06

    The world is facing more deaths due to increasing antibiotic-resistant bacterial infections and the shortage of new highly effective antibiotics, however the air media as its important transmission route has not been adequately studied. Based on the latest literature acquired in this work, we have discussed the state-of-the-art research progress of the concentration, distribution and spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in different environmental air media, and also analyzed some future prevention and control measures. The large use of antibiotics in the medical settings and animal husbandry places has resulted in higher abundances of ARB and ARGs in the relevant and surrounding atmosphere than in urban and general indoor air environments. ARGs can be spread by adhering to airborne particles, and researchers have also found that air media contain more abundant ARGs than other environmental media such as soil, water and sediment. It was suggested in this review that strengthening the monitoring, study on spreading factors and biological toxicity, and also research and development on pathogen accurate diagnosis and new green antibiotic are expected to help effectively monitor, prevent and control of the impacts of airborne resistant bacteria and resistance genes on both human and ecologies.

  14. Mapping of novel powdery mildew resistance gene(s) from Agropyron cristatum chromosome 2P.

    Science.gov (United States)

    Li, Huanhuan; Jiang, Bo; Wang, Jingchang; Lu, Yuqing; Zhang, Jinpeng; Pan, Cuili; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

    2017-01-01

    A physical map of Agropyron cristatum 2P chromosome was constructed for the first time and the novel powdery mildew resistance gene(s) from chromosome 2P was(were) also mapped. Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a wild relative of common wheat, is highly resistant to powdery mildew. Previous studies showed that wheat-A. cristatum 2P disomic addition line II-9-3 displayed high resistance to powdery mildew, and the resistance was attributable to A. cristatum chromosome 2P. To utilize and physically map the powdery mildew resistance gene(s), 15 wheat-A. cristatum 2P translocation lines and three A. cristatum 2P deletion lines with different chromosomal segment sizes, obtained from II-9-3 using 60 Co-γ ray irradiation, were characterized using cytogenetic and molecular marker analysis. A. cristatum 2P chromosomal segments in the translocations were translocated to different wheat chromosomes, including 1A, 4A, 5A, 6A, 7A, 1B, 2B, 3B, 7B, 3D, 4D, and 6D. A physical map of the 2P chromosome was constructed with 82 STS markers, consisting of nine bins with 34 markers on 2PS and eight bins with 48 markers on 2PL. The BC 1 F 2 populations of seven wheat-A. cristatum 2P translocation lines (2PT-3, 2PT-4, 2PT-5, 2PT-6, 2PT-8, 2PT-9, and 2PT-10) were developed by self-pollination, tested with powdery mildew and genotyped with 2P-specific STS markers. From these results, the gene(s) conferring powdery mildew resistance was(were) located on 2PL bin FL 0.66-0.86 and 19 2P-specific markers were identified in this bin. Moreover, two new powdery mildew-resistant translocation lines (2PT-4 and 2PT-5) with small 2PL chromosome segments were obtained. The newly developed wheat lines with powdery mildew resistance and the closely linked molecular markers will be valuable for wheat disease breeding in the future.

  15. Evolution by Pervasive Gene Fusion in Antibiotic Resistance and Antibiotic Synthesizing Genes

    Directory of Open Access Journals (Sweden)

    Orla Coleman

    2015-03-01

    Full Text Available Phylogenetic (tree-based approaches to understanding evolutionary history are unable to incorporate convergent evolutionary events where two genes merge into one. In this study, as exemplars of what can be achieved when a tree is not assumed a priori, we have analysed the evolutionary histories of polyketide synthase genes and antibiotic resistance genes and have shown that their history is replete with convergent events as well as divergent events. We demonstrate that the overall histories of these genes more closely resembles the remodelling that might be seen with the children’s toy Lego, than the standard model of the phylogenetic tree. This work demonstrates further that genes can act as public goods, available for re-use and incorporation into other genetic goods.

  16. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Science.gov (United States)

    Sahoo, Dipak K; Abeysekara, Nilwala S; Cianzio, Silvia R; Robertson, Alison E; Bhattacharyya, Madan K

    2017-01-01

    Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs) (F7 families) were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR)-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  17. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Directory of Open Access Journals (Sweden)

    Dipak K Sahoo

    Full Text Available Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs (F7 families were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  18. Conserving and enhancing biological control of nematodes.

    Science.gov (United States)

    Timper, Patricia

    2014-06-01

    Conservation biological control is the modification of the environment or existing practices to protect and enhance antagonistic organisms to reduce damage from pests. This approach to biological control has received insufficient attention compared with inundative applications of microbial antagonists to control nematodes. This review provides examples of how production practices can enhance or diminish biological control of plant-parasitic nematodes and other soilborne pests. Antagonists of nematodes can be enhanced by providing supplementary food sources such as occurs when organic amendments are applied to soil. However, some organic amendments (e.g., manures and plants containing allelopathic compounds) can also be detrimental to nematode antagonists. Plant species and genotype can strongly influence the outcome of biological control. For instance, the susceptibility of the plant to the nematode can determine the effectiveness of control; good hosts will require greater levels of suppression than poor hosts. Plant genotype can also influence the degree of rhizosphere colonization and antibiotic production by antagonists, as well the expression of induced resistance by plants. Production practices such as crop rotation, fallow periods, tillage, and pesticide applications can directly disrupt populations of antagonistic organisms. These practices can also indirectly affect antagonists by reducing their primary nematode host. One of the challenges of conservation biological control is that practices intended to protect or enhance suppression of nematodes may not be effective in all field sites because they are dependent on indigenous antagonists. Ultimately, indicators will need to be identified, such as the presence of particular antagonists, which can guide decisions on where it is practical to use conservation biological control. Antagonists can also be applied to field sites in conjunction with conservation practices to improve the consistency, efficacy, and

  19. Study on drug resistance of mycobacterium tuberculosis in patients with pulmonary tuberculosis by drug resistance gene detecting

    International Nuclear Information System (INIS)

    Wang Wei; Li Hongmin; Wu Xueqiong; Wang Ansheng; Ye Yixiu; Wang Zhongyuan; Liu Jinwei; Chen Hongbing; Lin Minggui; Wang Jinhe; Li Sumei; Jiang Ping; Feng Bai; Chen Dongjing

    2004-01-01

    To investigate drug resistance of mycobacterium tuberculosis in different age group, compare detecting effect of two methods and evaluate their the clinical application value, all of the strains of mycobacterium tuberculosis were tested for resistance to RFP, INH SM PZA and EMB by the absolute concentration method on Lowenstein-Jensen medium and the mutation of the rpoB, katG, rpsL, pncA and embB resistance genes in M. tuberculosis was tested by PCR-SSCP. In youth, middle and old age group, the rate of acquired drug resistance was 89.2%, 85.3% and 67.6% respectively, the gene mutation rate was 76.2%, 81.3% and 63.2% respectively. The rate of acquired drug resistance and multiple drug resistance in youth group was much higher than those in other groups. The gene mutation was correlated with drug resistance level of mycobacterium tuberculosis. The gene mutation rate was higher in strains isolated from high concentration resistance than those in strains isolated from low concentration resistance. The more irregular treatment was longer, the rate of drug resistance was higher. Acquired drug resistance varies in different age group. It suggested that surveillance of drug resistence in different age group should be taken seriously, especially in youth group. PCR - SSCP is a sensitive and specific method for rapid detecting rpoB, katG, rpsL, pncA and embB genes mutations of MTB. (authors)

  20. DNA tagging of blast resistant gene(s in three Brazilian rice cultivars

    Directory of Open Access Journals (Sweden)

    S.S. Sandhu

    2003-12-01

    Full Text Available Rice blast is the most important fungal disease of rice and is caused by Pyricularia oryzae Sacc. (Telomorph Magnoporthe grisea Barr.. Seven randomly amplified polymorphic DNA (RAPD markers OPA5, OPG17, OPG18, OPG19, OPF9, OPF17 and OPF19 showed very clear polymorphism in resistant cultivar lines which differed from susceptible lines. By comparing different susceptible lines, nine DNA amplifications of seven primers (OPA5(1000, OPA5(1200, OPG17(700, OPG18(850, OPG19(500, OPG19(600, OPF9(600, OPF17(1200 and OPF19(600 were identified as dominant markers for the blast resistant gene in resistant cultivar lines. These loci facilitate the indirect scoring of blast resistant and blast susceptible genotypes. The codomine RAPDs markers will facilitate marker-assisted selection of the blast resistant gene in two blast resistant genotypes of rice (Labelle and Line 11 and will be useful in rice breeding programs.

  1. Can the amount of digestible undegraded protein offered to ewes in late pregnancy affect the periparturient change in resistance to gastrointestinal nematodes?

    Science.gov (United States)

    Sebastiano, Rocco S; Sweeney, Torres; Keady, Timothy W J; Hanrahan, James P; Good, Barbara

    2017-02-15

    Ewes experience a temporary decline in resistance to gastrointestinal nematodes (GIN) during the periparturient period, characterised by a rise in faecal egg count (FEC) that represents a major source of pasture contamination for naïve progeny. The aim of this study was to assess the effect of level of supplementation with digestible undegraded protein (DUP) during the last 6 weeks of pregnancy on periparturient FEC and the performance of ewes with a naturally acquired parasite infection. Eighty-five Belclare and Belclare x Scottish Blackface twin/triplet-bearing ewes were allocated to 1 of 4 dietary groups representing the combination of 2 concentrates (DUP concentration 29 and 94g/kg dry matter) with 2 levels of concentrate during the final 6 weeks of gestation (18 and 30kg in total for ewes with twins; 24 and 35kg for ewes with triplets). All ewes were housed during the pre-partum feeding period and offered grass silage ad libitum; food intake was recorded daily. The intake of DUP varied from 26 to 72g/d among treatments and was reflected in variation of 0.76 to 1.20 in metabolizable protein supply as a proportion of requirements. After lambing, ewes and lambs grazed on permanent sheep pasture, without concentrate supplementation, until weaning (14 weeks post lambing). The variables studied, from week 6 pre-lambing up to week 10 post-lambing, included: FEC, serum pepsinogen concentration, body weight (BW) and body condition score (BCS). The effect of week (relative to lambing date) on FEC was highly significant (P0.05) at any stage either pre- or post-partum. Pepsinogen concentration also varied with time but was not influenced by dietary treatment (P>0.05). The changes in BW and BCS from 6 weeks before lambing to weaning were not affected by the concentration of DUP in the supplement but ewes on treatments involving the higher level of supplementation lost less BW and BCS (Pewes with a naturally acquired GIN infection. Copyright © 2017 Elsevier B.V. All

  2. Occurrence of the mcr-1 Colistin Resistance Gene and other Clinically Relevant Antibiotic Resistance Genes in Microbial Populations at Different Municipal Wastewater Treatment Plants in Germany

    Directory of Open Access Journals (Sweden)

    Norman Hembach

    2017-07-01

    Full Text Available Seven wastewater treatment plants (WWTPs with different population equivalents and catchment areas were screened for the prevalence of the colistin resistance gene mcr-1 mediating resistance against last resort antibiotic polymyxin E. The abundance of the plasmid-associated mcr-1 gene in total microbial populations during water treatment processes was quantitatively analyzed by qPCR analyses. The presence of the colistin resistance gene was documented for all of the influent wastewater samples of the seven WWTPs. In some cases the mcr-1 resistance gene was also detected in effluent samples of the WWTPs after conventional treatment reaching the aquatic environment. In addition to the occurrence of mcr-1 gene, CTX-M-32, blaTEM, CTX-M, tetM, CMY-2, and ermB genes coding for clinically relevant antibiotic resistances were quantified in higher abundances in all WWTPs effluents. In parallel, the abundances of Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli were quantified via qPCR using specific taxonomic gene markers which were detected in all influent and effluent wastewaters in significant densities. Hence, opportunistic pathogens and clinically relevant antibiotic resistance genes in wastewaters of the analyzed WWTPs bear a risk of dissemination to the aquatic environment. Since many of the antibiotic resistance gene are associated with mobile genetic elements horizontal gene transfer during wastewater treatment can't be excluded.

  3. RNA-Seq reveals the molecular mechanism of trapping and killing of root-knot nematodes by nematode-trapping fungi.

    Science.gov (United States)

    Pandit, Ramesh; Patel, Reena; Patel, Namrata; Bhatt, Vaibhav; Joshi, Chaitanya; Singh, Pawan Kumar; Kunjadia, Anju

    2017-04-01

    Nematode-trapping fungi are well known for their inherent potential to trap and kill nematodes using specialized trapping devices. However, the molecular mechanisms underlying the trapping and subsequent processes are still unclear. Therefore, in this study, we examined differential genes expression in two nematode-trapping fungi after baiting with nematode extracts. In Arthrobotrys conoides, 809 transcripts associated with diverse functions such as signal transduction, morphogenesis, stress response and peroxisomal proteins, proteases, chitinases and genes involved in the host-pathogen interaction showed differential expression with fold change (>±1.5 fold) in the presence of nematode extract with FDR (p-value nematode-trapping fungi for its host. The findings illustrate the molecular mechanism of fungal parasitism in A. conoides which may be helpful in developing a potential biocontrol agent against parasitic nematodes.

  4. Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter.

    Science.gov (United States)

    Li, Lili; Heidemann Olsen, Rikke; Ye, Lei; Yan, He; Nie, Qing; Meng, Hecheng; Shi, Lei

    2016-04-01

    The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across species, genes conferring antimicrobial resistance were observed with the following frequencies: blaTEM, 40.7%; blaCMY-2, 15.2%; blaCTX-M, 11.5%; sul2, 27.2%; sul1, 14.4%; tet(A), 5.4%; tet(L), 5.4%; tet(M), 5.0%; tet(E), 3.7%; tet(C), 3.3%; tet(S), 2.5%; and tet(K), 0.8%. Various antimicrobial resistance genes were found in new carriers: blaTEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; blaCMY-2 in Lactococcus lactis, Klebsiella oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6.6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor- encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance of aerobic bacteria from pork as reservoirs for antimicrobial resistance genes and mobile genetic elements that can readily be transferred intra- and interspecies.

  5. Parâmetros genéticos da resistência da soja ao nematóide de cisto Raça 1 Genetic parameters for soybean resistance to Race 1 cyst nematode

    Directory of Open Access Journals (Sweden)

    Mara Fernandes Moura

    2008-01-01

    Full Text Available O trabalho objetivou verificar o comportamento de Linhagens Endogâmicas Recombinantes (RIL's - Recombinant Imbred Lines, obtidas do cruzamento entre Hartwig (genitor resistente e EMGOPA-316 (genitor suscetível em relação à resistência ao nematóide de cisto da soja - NCS (raça 1 e a estimação de parâmetros genéticos e de progressos de seleção como implicação no melhoramento de plantas. Os parâmetros envolveram o índice de fêmeas (IF obtido na avaliação de 176 linhagens F6 de soja quanto à resistência ao NCS. Avaliaram-se os genótipos quanto à resposta ao NCS em casa de vegetação e calcularam-se as médias dos IF dos genótipos avaliados. Posteriormente, foram realizadas a distribuição de freqüência e a análise de variância e, então, estimado o número de locos segregantes envolvidos na resistência das linhagens ao NCS (raça 1. Estimou-se o progresso de seleção (i = -2,154 entre as linhagens avaliadas (com diferentes números de repetições, bem como a herdabilidade em nível de média (h². Assim conclui-se que: a A distribuição de normalidade das médias dos IF, bem como a estimativa da herdabilidade e a estimativa do número de locos segregantes indicam que a resposta das linhagens ao NCS (raça 1 tem caráter de herança poligênica; b Foram encontradas linhagens promissoras para resistência ao NCS, porém, como este é de difícil avaliação recomenda-se utilizar maior número de linhagens F6 na avaliação fenotípica e maior número de repetições para avaliação da reação ao NCS; c A necessidade de se fazer correção para efeitos macroambientais aumentou o erro das estimativas.This study aimed at verify the behavior of Recombinant Inbreed Lines, resulting of a cross between Hartwig (resistant parental and EMGOPA-316 (susceptible parental to NCS soybean nematode (race 1 and to estimate genetic parameters and those of selection progress. Estimated parameters used the mean female index (IF

  6. Opposing Forces of A/T-Biased Mutations and G/C-Biased Gene Conversions Shape the Genome of the Nematode Pristionchus pacificus

    Science.gov (United States)

    Weller, Andreas M.; Rödelsperger, Christian; Eberhardt, Gabi; Molnar, Ruxandra I.; Sommer, Ralf J.

    2014-01-01

    Base substitution mutations are a major source of genetic novelty and mutation accumulation line (MAL) studies revealed a nearly universal AT bias in de novo mutation spectra. While a comparison of de novo mutation spectra with the actual nucleotide composition in the genome suggests the existence of general counterbalancing mechanisms, little is known about the evolutionary and historical details of these opposing forces. Here, we correlate MAL-derived mutation spectra with patterns observed from population resequencing. Variation observed in natural populations has already been subject to evolutionary forces. Distinction between rare and common alleles, the latter of which are close to fixation and of presumably older age, can provide insight into mutational processes and their influence on genome evolution. We provide a genome-wide analysis of de novo mutations in 22 MALs of the nematode Pristionchus pacificus and compare the spectra with natural variants observed in resequencing of 104 natural isolates. MALs show an AT bias of 5.3, one of the highest values observed to date. In contrast, the AT bias in natural variants is much lower. Specifically, rare derived alleles show an AT bias of 2.4, whereas common derived alleles close to fixation show no AT bias at all. These results indicate the existence of a strong opposing force and they suggest that the GC content of the P. pacificus genome is in equilibrium. We discuss GC-biased gene conversion as a potential mechanism acting against AT-biased mutations. This study provides insight into genome evolution by combining MAL studies with natural variation. PMID:24414549

  7. Candidate gene association analyses for ketosis resistance in Holsteins.

    Science.gov (United States)

    Kroezen, V; Schenkel, F S; Miglior, F; Baes, C F; Squires, E J

    2018-06-01

    High-yielding dairy cattle are susceptible to ketosis, a metabolic disease that negatively affects the health, fertility, and milk production of the cow. Interest in breeding for more robust dairy cattle with improved resistance to disease is global; however, genetic evaluations for ketosis would benefit from the additional information provided by genetic markers. Candidate genes that are proposed to have a biological role in the pathogenesis of ketosis were investigated in silico and a custom panel of 998 putative single nucleotide polymorphism (SNP) markers was developed. The objective of this study was to test the associations of these new markers with deregressed estimated breeding values (EBV) for ketosis. A sample of 653 Canadian Holstein cows that had been previously genotyped with a medium-density SNP chip were regenotyped with the custom panel. The EBV for ketosis in first and later lactations were obtained for each animal and deregressed for use as pseudo-phenotypes for association analyses. Results of the mixed inheritance model for single SNP association analyses suggested 15 markers in 6 unique candidate genes were associated with the studied trait. Genes encoding proteins involved in metabolic processes, including the synthesis and degradation of fatty acids and ketone bodies, gluconeogenesis, lipid mobilization, and the citric acid cycle, were identified to contain SNP associated with ketosis resistance. This work confirmed the presence of previously described quantitative trait loci for dairy cattle, suggested novel markers for ketosis-resistance, and provided insight into the underlying biology of this disease. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. Parasitic nematode interactions with mammals and plants.

    Science.gov (United States)

    Jasmer, Douglas P; Goverse, Aska; Smant, Geert

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

  9. Molecular study on some antibiotic resistant genes in Salmonella spp. isolates

    Science.gov (United States)

    Nabi, Ari Q.

    2017-09-01

    Studying the genes related with antimicrobial resistance in Salmonella spp. is a crucial step toward a correct and faster treatment of infections caused by the pathogen. In this work Integron mediated antibiotic resistant gene IntI1 (Class I Integrase IntI1) and some plasmid mediated antibiotic resistance genes (Qnr) were scanned among the isolated non-Typhoid Salmonellae strains with known resistance to some important antimicrobial drugs using Sybr Green real time PCR. The aim of the study was to correlate the multiple antibiotics and antimicrobial resistance of Salmonella spp. with the presence of integrase (IntI1) gene and plasmid mediated quinolone resistant genes. Results revealed the presence of Class I Integrase gene in 76% of the isolates with confirmed multiple antibiotic resistances. Moreover, about 32% of the multiple antibiotic resistant serotypes showed a positive R-PCR for plasmid mediated qnrA gene encoding for nalidixic acid and ciprofloxacin resistance. No positive results could be revealed form R-PCRs targeting qnrB or qnrS. In light of these results we can conclude that the presence of at least one of the qnr genes and/or the presence of Integrase Class I gene were responsible for the multiple antibiotic resistance to for nalidixic acid and ciprofloxacin from the studied Salmonella spp. and further studies required to identify the genes related with multiple antibiotic resistance of the pathogen.

  10. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1-a Pseudomonas sp.) and thermophilic (Iso T10-a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457-0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130-0.486, P = 0.075-0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene

  11. Genetic mapping of the rice resistance-breaking gene of the brown planthopper Nilaparvata lugens

    OpenAIRE

    Kobayashi, Tetsuya; Yamamoto, Kimiko; Suetsugu, Yoshitaka; Kuwazaki, Seigo; Hattori, Makoto; Jairin, Jirapong; Sanada-Morimura, Sachiyo; Matsumura, Masaya

    2014-01-01

    Host plant resistance has been widely used for controlling the major rice pest brown planthopper (BPH, Nilaparvata lugens). However, adaptation of the wild BPH population to resistance limits the effective use of resistant rice varieties. Quantitative trait locus (QTL) analysis was conducted to identify resistance-breaking genes against the anti-feeding mechanism mediated by the rice resistance gene Bph1. QTL analysis in iso-female BPH lines with single-nucleotide polymorphism (SNP) markers d...

  12. Analysis of differentially expressed genes related to resistance in spinosad- and neonicotinoid-resistant Musca domestica L. (Diptera: Muscidae) strains

    DEFF Research Database (Denmark)

    Castberg, Dorte Heidi Højland; Kristensen, Michael

    2017-01-01

    strains differing significantly in their response to insecticides. High differential expression of P450s and genes coding for cuticle protein indicates a combination of factors involved in metabolic neonicotinoid and spinosad resistance. Conclusion Resistance in these strains is apparently not linked...... interesting in terms of neonicotinoid resistance, while cyp4d9 was overexpressed in 791spin compared to spinosad-susceptible strains. GSTs, ESTs and UGTs were mostly overexpressed, but not to the same degree as P450s. We present a comprehensive and comparative picture of gene expression in three housefly......Background The housefly is a global pest that has developed resistance to most insecticides applied against it. Resistance of the spinosad-resistant strain 791spin and the neonicotinoid-resistant 766b strain is believed to be due to metabolism. We investigate differentially expressed genes...

  13. Suppression of NGB and NAB/ERabp1 in tomato modifies root responses to potato cyst nematode infestation.

    Science.gov (United States)

    Dąbrowska-Bronk, Joanna; Czarny, Magdalena; Wiśniewska, Anita; Fudali, Sylwia; Baranowski, Łukasz; Sobczak, Mirosław; Święcicka, Magdalena; Matuszkiewicz, Mateusz; Brzyżek, Grzegorz; Wroblewski, Tadeusz; Dobosz, Renata; Bartoszewski, Grzegorz; Filipecki, Marcin

    2015-05-01

    Plant-parasitic nematodes cause significant damage to major crops throughout the world. The small number of genes conferring natural plant resistance and the limitations of chemical control require the development of new protective strategies. RNA interference or the inducible over-expression of nematicidal genes provides an environment-friendly approach to this problem. Candidate genes include NGB, which encodes a small GTP-binding protein, and NAB/ERabp1, which encodes an auxin-binding protein, which were identified as being up-regulated in tomato roots in a transcriptome screen of potato cyst nematode (Globodera rostochiensis) feeding sites. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization confirmed the localized up-regulation of these genes in syncytia and surrounding cells following nematode infection. Gene-silencing constructs were introduced into tomato, resulting in a 20%-98% decrease in transcription levels. Nematode infection tests conducted on transgenic plants showed 57%-82% reduction in the number of G. rostochiensis females in vitro and 30%-46% reduction in pot trials. Transmission electron microscopy revealed a deterioration of cytoplasm, and degraded mitochondria and plastids, in syncytia induced in plants with reduced NAB/ERabp1 expression. Cytoplasm in syncytia induced in plants with low NGB expression was strongly electron translucent and contained very few ribosomes; however, mitochondria and plastids remained intact. Functional impairments in syncytial cytoplasm of silenced plants may result from NGB's role in ribosome biogenesis; this was confirmed by localization of yellow fluorescent protein (YFP)-labelled NGB protein in nucleoli and co-repression of NGB in plants with reduced NAB/ERabp1 expression. These results demonstrate that NGB and NAB/ERabp1 play important roles in the development of nematode-induced syncytia. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  14. Nematode-Trapping Fungi.

    Science.gov (United States)

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  15. Sulfonamide-resistant bacteria and their resistance genes in soils fertilized with manures from Jiangsu Province, Southeastern China.

    Science.gov (United States)

    Wang, Na; Yang, Xiaohong; Jiao, Shaojun; Zhang, Jun; Ye, Boping; Gao, Shixiang

    2014-01-01

    Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs) increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (psulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China.

  16. Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter

    DEFF Research Database (Denmark)

    Li, Lili; Olsen, Rikke Heidemann; Ye, Lei

    2016-01-01

    The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bac......The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram......-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across.......6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor– encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance...

  17. Genetic architecture of wild soybean (Glycine soja) response to soybean cyst nematode (Heterodera glycines).

    Science.gov (United States)

    Zhang, Hengyou; Song, Qijian; Griffin, Joshua D; Song, Bao-Hua

    2017-12-01

    The soybean cyst nematode (SCN) is one of the most destructive pathogens of soybean plants worldwide. Host-plant resistance is an environmentally friendly method to mitigate SCN damage. To date, the resistant soybean cultivars harbor limited genetic variation, and some are losing resistance. Thus, a better understanding of the genetic mechanisms of the SCN resistance, as well as developing diverse resistant soybean cultivars, is urgently needed. In this study, a genome-wide association study (GWAS) was conducted using 1032 wild soybean (Glycine soja) accessions with over 42,000 single-nucleotide polymorphisms (SNPs) to understand the genetic architecture of G. soja resistance to SCN race 1. Ten SNPs were significantly associated with the response to race 1. Three SNPs on chromosome 18 were localized within the previously identified quantitative trait loci (QTLs), and two of which were localized within a strong linkage disequilibrium block encompassing a nucleotide-binding (NB)-ARC disease resistance gene (Glyma.18G102600). Genes encoding methyltransferases, the calcium-dependent signaling protein, the leucine-rich repeat kinase family protein, and the NB-ARC disease resistance protein, were identified as promising candidate genes. The identified SNPs and candidate genes can not only shed light on the molecular mechanisms underlying SCN resistance, but also can facilitate soybean improvement employing wild genetic resources.

  18. Phylogency and Evolution of Nematodes

    NARCIS (Netherlands)

    Bert, W.; Karssen, G.; Helder, J.

    2011-01-01

    Many plant-parasitic nematodes including members of the genera Meloidogyne (root-knot nematodes), Heterodera and Globodera (cyst nematodes) and Pratylenchus (lesion nematodes) are studied as they cause major damage to crops such as potato, tomato, soybean and sugar beet. Both for fundamental reasons

  19. Host range of antibiotic resistance genes in wastewater treatment plant influent and effluent.

    Science.gov (United States)

    Hultman, Jenni; Tamminen, Manu; Pärnänen, Katariina; Cairns, Johannes; Karkman, Antti; Virta, Marko

    2018-04-01

    Wastewater treatment plants (WWTPs) collect wastewater from various sources for a multi-step treatment process. By mixing a large variety of bacteria and promoting their proximity, WWTPs constitute potential hotspots for the emergence of antibiotic resistant bacteria. Concerns have been expressed regarding the potential of WWTPs to spread antibiotic resistance genes (ARGs) from environmental reservoirs to human pathogens. We utilized epicPCR (Emulsion, Paired Isolation and Concatenation PCR) to detect the bacterial hosts of ARGs in two WWTPs. We identified the host distribution of four resistance-associated genes (tetM, int1, qacEΔ1and blaOXA-58) in influent and effluent. The bacterial hosts of these resistance genes varied between the WWTP influent and effluent, with a generally decreasing host range in the effluent. Through 16S rRNA gene sequencing, it was determined that the resistance gene carrying bacteria include both abundant and rare taxa. Our results suggest that the studied WWTPs mostly succeed in decreasing the host range of the resistance genes during the treatment process. Still, there were instances where effluent contained resistance genes in bacterial groups not carrying these genes in the influent. By permitting exhaustive profiling of resistance-associated gene hosts in WWTP bacterial communities, the application of epicPCR provides a new level of precision to our resistance gene risk estimates.

  20. Clusters of Antibiotic Resistance Genes Enriched Together Stay Together in Swine Agriculture.

    Science.gov (United States)

    Johnson, Timothy A; Stedtfeld, Robert D; Wang, Qiong; Cole, James R; Hashsham, Syed A; Looft, Torey; Zhu, Yong-Guan; Tiedje, James M

    2016-04-12

    Antibiotic resistance is a worldwide health risk, but the influence of animal agriculture on the genetic context and enrichment of individual antibiotic resistance alleles remains unclear. Using quantitative PCR followed by amplicon sequencing, we quantified and sequenced 44 genes related to antibiotic resistance, mobile genetic elements, and bacterial phylogeny in microbiomes from U.S. laboratory swine and from swine farms from three Chinese regions. We identified highly abundant resistance clusters: groups of resistance and mobile genetic element alleles that cooccur. For example, the abundance of genes conferring resistance to six classes of antibiotics together with class 1 integrase and the abundance of IS6100-type transposons in three Chinese regions are directly correlated. These resistance cluster genes likely colocalize in microbial genomes in the farms. Resistance cluster alleles were dramatically enriched (up to 1 to 10% as abundant as 16S rRNA) and indicate that multidrug-resistant bacteria are likely the norm rather than an exception in these communities. This enrichment largely occurred independently of phylogenetic composition; thus, resistance clusters are likely present in many bacterial taxa. Furthermore, resistance clusters contain resistance genes that confer resistance to antibiotics independently of their particular use on the farms. Selection for these clusters is likely due to the use of only a subset of the broad range of chemicals to which the clusters confer resistance. The scale of animal agriculture and its wastes, the enrichment and horizontal gene transfer potential of the clusters, and the vicinity of large human populations suggest that managing this resistance reservoir is important for minimizing human risk. Agricultural antibiotic use results in clusters of cooccurring resistance genes that together confer resistance to multiple antibiotics. The use of a single antibiotic could select for an entire suite of resistance genes if

  1. Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China

    International Nuclear Information System (INIS)

    Tao Ran; Ying Guangguo; Su Haochang; Zhou Hongwei; Sidhu, Jatinder P.S.

    2010-01-01

    This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected. However, multiple drug resistance in bacterial isolates from the other sites of Pearl rivers was observed which is possibly due to sewage discharge and input from other anthropogenic sources along the rivers. Four tetracycline resistance genes tet A, tet B, tet C and tet D were detected in the isolates from the rivers. The genes tet A and tet B were widely detected with the detection frequencies of 43% and 40% respectively. Ciprofloxacin and levofloxacin resistant enteric bacteria were also isolated from the pig and duck manures which suggest a wider distribution of human specific drugs in the environment. This investigation provided a baseline data on antibiotic resistance profiles and tetracycline resistance genes in the Pearl rivers delta. - High rates of antibiotic resistance in Enterobacteriaceae from river water are attributed to wastewater contamination.

  2. Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China

    Energy Technology Data Exchange (ETDEWEB)

    Tao Ran [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Su Haochang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhou Hongwei [Department of Environmental Health, School of Public Health and Tropical Medicine, Southern Medical University, 1838 North Guangzhou Street, Baiyun District, Guangzhou 510515 (China); Sidhu, Jatinder P.S. [CSIRO Land and Water, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia QLD 4067 (Australia)

    2010-06-15

    This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected. However, multiple drug resistance in bacterial isolates from the other sites of Pearl rivers was observed which is possibly due to sewage discharge and input from other anthropogenic sources along the rivers. Four tetracycline resistance genes tet A, tet B, tet C and tet D were detected in the isolates from the rivers. The genes tet A and tet B were widely detected with the detection frequencies of 43% and 40% respectively. Ciprofloxacin and levofloxacin resistant enteric bacteria were also isolated from the pig and duck manures which suggest a wider distribution of human specific drugs in the environment. This investigation provided a baseline data on antibiotic resistance profiles and tetracycline resistance genes in the Pearl rivers delta. - High rates of antibiotic resistance in Enterobacteriaceae from river water are attributed to wastewater contamination.

  3. Field efficacy of four anthelmintics and confirmation of drug-resistant nematodes by controlled efficacy test and pyrosequencing on a sheep and goat farm in Denmark.

    Science.gov (United States)

    Peña-Espinoza, Miguel; Thamsborg, Stig M; Demeler, Janina; Enemark, Heidi L

    2014-12-15

    We describe a case of anthelmintic resistance on one of the largest organic small ruminant farms in Denmark. The flock was established in 2007 by purchase of animals from other Danish farms and had history of clinical parasitism, high mortality of young stock and anthelmintic treatment failure. In October 2011, 40 lambs and 40 kids were selected for a faecal egg count reduction test (FECRT) with fenbendazole (FBZ), ivermectin (IVM), moxidectin (MOX) and levamisole (LEV). Lambs were treated with the recommended sheep dose of each product while kids received the sheep dose of IVM, 1.5× sheep dose of MOX and 2× sheep dose of FBZ and LEV. Untreated lambs and kids were also included and three methods for calculating faecal egg count (FEC) reduction were compared. In a subsequent investigation, a controlled efficacy test (CET) with FBZ and IVM was performed in lambs infected with Haemonchus contortus and Trichostrongylus colubriformis isolated from adult goats on the farm. Recovered specimens of H. contortus were subjected to pyrosequencing for detection of single nucleotide polymorphisms (SNPs) related to benzimidazole (BZ) resistance. During the FECRT, FECs in untreated lambs dropped significantly by 47%. No FEC reduction was detected in untreated kids. After FBZ treatments, FEC reductions in lambs and kids ranged from 15 to 54% and 49-56%, respectively, according to the different calculation methods. Post IVM treatments, FEC reductions in lambs and kids varied between 71-90% and 81-83%, correspondingly. LEV and MOX reduced FECs by 98-100% in both species. In the CET, FBZ reduced H. contortus worm counts by 52-56% and no reduction in T. colubriformis counts were detected after treatment. IVM eliminated 100% of H. contortus and reduced T. colubriformis counts by 84-92%, according to different calculation methods. Pyrosequencing of isolated H. contortus revealed increased frequencies of the BZ resistance-related SNP in codon 200 of the β-tubulin isotype 1 gene

  4. Seleção para resistência de genótipos de cenoura aos nematóides-das-galhas Selection for carrot genotypes resistance to root-knot nematodes in field and greenhouse

    Directory of Open Access Journals (Sweden)

    Giovani O da Silva

    2011-09-01

    Full Text Available Foi verificada a relação entre caracteres avaliados em campo e casa-de-vegetação, relativos à avaliação de genótipos de cenoura quanto à resistência ao nematóide-das-galhas (Meloidogyne spp., visando identificar quais caracteres possibilitam a diferenciação entre os genótipos e verificar a possibilidade de avaliação apenas em um ambiente ou a eliminação de caracteres que apresentem correlação alta. Avaliaram-se 38 progênies da população '0812518' e 31 progênies da população '0812519', além das cultivares Brasília e Kuronan como testemunhas tolerante e suscetível, respectivamente. Em campo naturalmente infestado por uma mistura de Meloidogyne incognita raça 1 e Meloidoigyne javanica, a seleção para resistência ao nematóide-das-galhas foi realizada com base na menor porcentagem de infecção na raiz principal dos genótipos de cenoura, rendimento de raiz e o fator de reprodução, enquanto que em casa-de-vegetação, para cada uma das mesmas espécies de nematóides e também para a mistura de ambas, foi medido o índice de galhas e índice de massa de ovos. Verificou-se que não houve possibilidade de seleção em apenas um dos ambientes testados ou a eliminação de caracteres, indicando que para a obtenção de cultivares mais produtivas e mais tolerantes é necessária a seleção combinada nos diferentes caracteres e ambientes. Para o experimento realizado em campo foi possível diferenciar os genótipos apenas para o rendimento de raiz. No experimento em casa-de-vegetação, para todos os caracteres foi possível identificar genótipos superiores. Porém, as médias das populações não foram melhores que a testemunha 'Brasília' da qual estas se originaram, confirmando a necessidade da busca por métodos mais eficientes de seleção.We verified the relation among the evaluated characters in field and greenhouse, concerning to the evaluation to root-knot nematode (Meloidogyne spp. for the carrot crop, to

  5. Strategy of gene silencing in cassava for validation of resistance genes

    International Nuclear Information System (INIS)

    Cortes, Simon; Lopez, Camilo

    2010-01-01

    Cassava (Manihot esculenta) is a major source of food for more than 1000 million people in the world and constitutes an important staple crop. Cassava bacterial blight, caused by the gram negative bacterium Xanthomonas axonopodis pv. manihotis, is one of the most important constraints for this crop. A candidate resistance gene against cassava bacterial blight, named RXam1, has been identified previously. In this work, we employed the gene silencing approach using the African cassava mosaic virus (ACMV) to validate the function of the RXam1 gene. We used as positive control the su gen, which produce photo blanching in leaves when is silenced. Plants from the SG10735 variety were bombardment with the ACMV-A-SU+ACMV-B y ACMV-A-RXam1+ACMV-B constructions. The silencing efficiency employing the su gene was low, only one of seven plants showed photo blanching. In the putative silenced plants for the RXam1 gene, no presence of siRNAs corresponding to RXam1 was observed; although a low diminution of the RXam1 gene expression was obtained. The growth curves for the Xam strain CIO136 in cassava plants inoculated showing a little but no significance difference in the susceptibility in the silenced plants compared to not silenced

  6. Functional screen for genes responsible for tamoxifen resistance in human breast cancer cells

    NARCIS (Netherlands)

    Meijer, Danielle; van Agthoven, Ton; Bosma, Peter T.; Nooter, Kees; Dorssers, Lambert C. J.

    2006-01-01

    Antiestrogens, such as tamoxifen, are widely used for endocrine treatment of estrogen receptor-positive breast cancer. However, as breast cancer progresses, development of tamoxifen resistance is inevitable. The mechanisms underlying this resistance are not well understood. To identify genes

  7. Analysis of non-TIR NBS-LRR resistance gene analogs in Musa acuminata Colla: Isolation, RFLP marker development, and physical mapping

    Directory of Open Access Journals (Sweden)

    Souza Manoel T

    2008-01-01

    Full Text Available Abstract Background Many commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives, by contrast, possess greater variability and represent potential sources of disease resistance genes (R-genes. The largest known family of plant R-genes encode proteins with nucleotide-binding site (NBS and C-terminal leucine-rich repeat (LRR domains. Conserved motifs in such genes in diverse plant species offer a means for isolation of candidate genes in banana which may be involved in plant defence. Results A computational strategy was developed for unbiased conserved motif discovery in NBS and LRR domains in R-genes and homologues in monocotyledonous plant species. Degenerate PCR primers targeting conserved motifs were tested on the wild cultivar Musa acuminata subsp. burmannicoides, var. Calcutta 4, which is resistant to a number of fungal pathogens and nematodes. One hundred and seventy four resistance gene analogs (RGAs were amplified and assembled into 52 contiguous sequences. Motifs present were typical of the non-TIR NBS-LRR RGA subfamily. A phylogenetic analysis of deduced amino-acid sequences for 33 RGAs with contiguous open reading frames (ORFs, together with RGAs from Arabidopsis thaliana and Oryza sativa, grouped most Musa RGAs within monocotyledon-specific clades. RFLP-RGA markers were developed, with 12 displaying distinct polymorphisms in parentals and F1 progeny of a diploid M. acuminata mapping population. Eighty eight BAC clones were identified in M. acuminata Calcutta 4, M. acuminata Grande Naine, and M. balbisiana Pisang Klutuk Wulung BAC libraries when hybridized to two RGA probes. Multiple copy RGAs were common within BAC clones, potentially representing variation reservoirs for evolution of new R-gene specificities. Conclusion This is the first large scale analysis of NBS-LRR RGAs in M. acuminata Calcutta 4. Contig sequences were

  8. A maize resistance gene functions against bacterial streak disease in rice

    OpenAIRE

    Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

    2005-01-01

    Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, wh...

  9. Comparative genomic and transcriptomic analysis of selected fatty acid biosynthesis genes and CNL disease resistance genes in oil palm

    Science.gov (United States)

    Rosli, Rozana; Amiruddin, Nadzirah; Ab Halim, Mohd Amin; Chan, Pek-Lan; Chan, Kuang-Lim; Azizi, Norazah; Morris, Priscilla E.; Leslie Low, Eng-Ti; Ong-Abdullah, Meilina; Sambanthamurthi, Ravigadevi; Singh, Rajinder

    2018-01-01

    Comparative genomics and transcriptomic analyses were performed on two agronomically important groups of genes from oil palm versus other major crop species and the model organism, Arabidopsis thaliana. The first analysis was of two gene families with key roles in regulation of oil quality and in particular the accumulation of oleic acid, namely stearoyl ACP desaturases (SAD) and acyl-acyl carrier protein (ACP) thioesterases (FAT). In both cases, these were found to be large gene families with complex expression profiles across a wide range of tissue types and developmental stages. The detailed classification of the oil palm SAD and FAT genes has enabled the updating of the latest version of the oil palm gene model. The second analysis focused on disease resistance (R) genes in order to elucidate possible candidates for breeding of pathogen tolerance/resistance. Ortholog analysis showed that 141 out of the 210 putative oil palm R genes had homologs in banana and rice. These genes formed 37 clusters with 634 orthologous genes. Classification of the 141 oil palm R genes showed that the genes belong to the Kinase (7), CNL (95), MLO-like (8), RLK (3) and Others (28) categories. The CNL R genes formed eight clusters. Expression data for selected R genes also identified potential candidates for breeding of disease resistance traits. Furthermore, these findings can provide information about the species evolution as well as the identification of agronomically important genes in oil palm and other major crops. PMID:29672525

  10. Comparative genomic and transcriptomic analysis of selected fatty acid biosynthesis genes and CNL disease resistance genes in oil palm.

    Science.gov (United States)

    Rosli, Rozana; Amiruddin, Nadzirah; Ab Halim, Mohd Amin; Chan, Pek-Lan; Chan, Kuang-Lim; Azizi, Norazah; Morris, Priscilla E; Leslie Low, Eng-Ti; Ong-Abdullah, Meilina; Sambanthamurthi, Ravigadevi; Singh, Rajinder; Murphy, Denis J

    2018-01-01

    Comparative genomics and transcriptomic analyses were performed on two agronomically important groups of genes from oil palm versus other major crop species and the model organism, Arabidopsis thaliana. The first analysis was of two gene families with key roles in regulation of oil quality and in particular the accumulation of oleic acid, namely stearoyl ACP desaturases (SAD) and acyl-acyl carrier protein (ACP) thioesterases (FAT). In both cases, these were found to be large gene families with complex expression profiles across a wide range of tissue types and developmental stages. The detailed classification of the oil palm SAD and FAT genes has enabled the updating of the latest version of the oil palm gene model. The second analysis focused on disease resistance (R) genes in order to elucidate possible candidates for breeding of pathogen tolerance/resistance. Ortholog analysis showed that 141 out of the 210 putative oil palm R genes had homologs in banana and rice. These genes formed 37 clusters with 634 orthologous genes. Classification of the 141 oil palm R genes showed that the genes belong to the Kinase (7), CNL (95), MLO-like (8), RLK (3) and Others (28) categories. The CNL R genes formed eight clusters. Expression data for selected R genes also identified potential candidates for breeding of disease resistance traits. Furthermore, these findings can provide information about the species evolution as well as the identification of agronomically important genes in oil palm and other major crops.

  11. The diversity of antimicrobial resistance genes among staphylococci of animal origin.

    Science.gov (United States)

    Wendlandt, Sarah; Feßler, Andrea T; Monecke, Stefan; Ehricht, Ralf; Schwarz, Stefan; Kadlec, Kristina

    2013-08-01

    Staphylococci of animal origin harbor a wide variety of resistance genes. So far, more than 40 different resistance genes have been identified in staphylococci from animals. This includes genes that confer resistance to virtually all classes of antimicrobial agents approved for use in animals, such as penicillins, cephalosporins, tetracyclines, macrolides, lincosamides, phenicols, aminoglycosides, aminocyclitols, pleuromutilins, and diaminopyrimidines. The gene products of some of these resistance genes confer resistance to only specific members of a class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents. The resistance mechanisms specified by the resistance genes fall into three major categories: (i) enzymatic inactivation, (ii) active efflux, or (iii) protection/modification/replacement of the cellular target sites of the antimicrobial agents. Mobile genetic elements, in particular plasmids and transposons, play a major role as carriers of antimicrobial resistance genes in animal staphylococci. They facilitate the exchange of resistance genes with staphylococci of human origin but also with other Gram-positive bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  12. A ubiquitin carboxyl extension protein secreted from a plant-parasitic nematode Globodera rostochiensis is cleaved in planta to promote plant parasitism.

    Science.gov (United States)

    Chronis, Demosthenis; Chen, Shiyan; Lu, Shunwen; Hewezi, Tarek; Carpenter, Sara C D; Loria, Rosemary; Baum, Thomas J; Wang, Xiaohong

    2013-04-01

    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. © 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.

  13. Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste.

    Directory of Open Access Journals (Sweden)

    Getahun E Agga

    Full Text Available This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie. Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR Gram-negative (Escherichia coli and Salmonella enterica and Gram-positive (enterococci bacteria were determined from individual samples (n = 174. The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44 by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine, low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05 in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar

  14. Thioridazine affects transcription of genes involved in cell wall biosynthesis in methicillin-resistant Staphylococcus aureus

    DEFF Research Database (Denmark)

    Bonde, Mette; Højland, Dorte Heidi; Kolmos, Hans Jørn

    2011-01-01

    have previously shown that the expression of some resistance genes is abolished after treatment with thioridazine and oxacillin. To further understand the mechanism underlying the reversal of resistance, we tested the expression of genes involved in antibiotic resistance and cell wall biosynthesis...... in response to thioridazine in combination with oxacillin. We observed that the oxacillin-induced expression of genes belonging to the VraSR regulon is reduced by the addition of thioridazine. The exclusion of such key factors involved in cell wall biosynthesis will most likely lead to a weakened cell wall...... reversal of resistance by thioridazine relies on decreased expression of specific genes involved in cell wall biosynthesis....

  15. Candidate genes for cross-resistance against DNA-damaging drugs

    DEFF Research Database (Denmark)

    Wittig, Rainer; Nessling, Michelle; Will, Rainer D

    2002-01-01

    Drug resistance of tumor cells leads to major drawbacks in the treatment of cancer. To identify candidate genes for drug resistance, we compared the expression patterns of the drug-sensitive human malignant melanoma cell line MeWo and three derived sublines with acquired resistance to the DNA...... as several apoptosis-related genes, in particular STK17A and CRYAB. As MPP1 and CRYAB are also among the 14 genes differentially expressed in all three of the drug-resistant sublines, they represent the strongest candidates for resistance against DNA-damaging drugs....

  16. Searching for resistance genes to Bursaphelenchus xylophilus using high throughput screening

    Directory of Open Access Journals (Sweden)

    Santos Carla S

    2012-11-01

    Full Text Available Abstract Background Pine wilt disease (PWD, caused by the pinewood nematode (PWN; Bursaphelenchus xylophilus, damages and kills pine trees and is causing serious economic damage worldwide. Although the ecological mechanism of infestation is well described, the plant’s molecular response to the pathogen is not well known. This is due mainly to the lack of genomic information and the complexity of the disease. High throughput sequencing is now an efficient approach for detecting the expression of genes in non-model organisms, thus providing valuable information in spite of the lack of the genome sequence. In an attempt to unravel genes potentially involved in the pine defense against the pathogen, we hereby report the high throughput comparative sequence analysis of infested and non-infested stems of Pinus pinaster (very susceptible to PWN and Pinus pinea (less susceptible to PWN. Results Four cDNA libraries from infested and non-infested stems of P. pinaster and P. pinea were sequenced in a full 454 GS FLX run, producing a total of 2,083,698 reads. The putative amino acid sequences encoded by the assembled transcripts were annotated according to Gene Ontology, to assign Pinus contigs into Biological Processes, Cellular Components and Molecular Functions categories. Most of the annotated transcripts corresponded to Picea genes-25.4-39.7%, whereas a smaller percentage, matched Pinus genes, 1.8-12.8%, probably a consequence of more public genomic information available for Picea than for Pinus. The comparative transcriptome analysis showed that when P. pinaster was infested with PWN, the genes malate dehydrogenase, ABA, water deficit stress related genes and PAR1 were highly expressed, while in PWN-infested P. pinea, the highly expressed genes were ricin B-related lectin, and genes belonging to the SNARE and high mobility group families. Quantitative PCR experiments confirmed the differential gene expression between the two pine species

  17. Searching for resistance genes to Bursaphelenchus xylophilus using high throughput screening

    Science.gov (United States)

    2012-01-01

    Background Pine wilt disease (PWD), caused by the pinewood nematode (PWN; Bursaphelenchus xylophilus), damages and kills pine trees and is causing serious economic damage worldwide. Although the ecological mechanism of infestation is well described, the plant’s molecular response to the pathogen is not well known. This is due mainly to the lack of genomic information and the complexity of the disease. High throughput sequencing is now an efficient approach for detecting the expression of genes in non-model organisms, thus providing valuable information in spite of the lack of the genome sequence. In an attempt to unravel genes potentially involved in the pine defense against the pathogen, we hereby report the high throughput comparative sequence analysis of infested and non-infested stems of Pinus pinaster (very susceptible to PWN) and Pinus pinea (less susceptible to PWN). Results Four cDNA libraries from infested and non-infested stems of P. pinaster and P. pinea were sequenced in a full 454 GS FLX run, producing a total of 2,083,698 reads. The putative amino acid sequences encoded by the assembled transcripts were annotated according to Gene Ontology, to assign Pinus contigs into Biological Processes, Cellular Components and Molecular Functions categories. Most of the annotated transcripts corresponded to Picea genes-25.4-39.7%, whereas a smaller percentage, matched Pinus genes, 1.8-12.8%, probably a consequence of more public genomic information available for Picea than for Pinus. The comparative transcriptome analysis showed that when P. pinaster was infested with PWN, the genes malate dehydrogenase, ABA, water deficit stress related genes and PAR1 were highly expressed, while in PWN-infested P. pinea, the highly expressed genes were ricin B-related lectin, and genes belonging to the SNARE and high mobility group families. Quantitative PCR experiments confirmed the differential gene expression between the two pine species. Conclusions Defense-related genes

  18. Survey of nematodes associated with terrestrial slugs in Norway.

    Science.gov (United States)

    Ross, J L; Ivanova, E S; Hatteland, B A; Brurberg, M B; Haukeland, S

    2016-09-01

    A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.

  19. Antibiotic resistance genes in anaerobic bacteria isolated from primary dental root canal infections.

    Science.gov (United States)

    Rôças, Isabela N; Siqueira, José F

    2012-12-01

    Fourty-one bacterial strains isolated from infected dental root canals and identified by 16S rRNA gene sequence were screened for the presence of 14 genes encoding resistance to beta-lactams, tetracycline and macrolides. Thirteen isolates (32%) were positive for at least one of the target antibiotic resistance genes. These strains carrying at least one antibiotic resistance gene belonged to 11 of the 26 (42%) infected root canals sampled. Two of these positive cases had two strains carrying resistance genes. Six out of 7 Fusobacterium strains harbored at least one of the target resistance genes. One Dialister invisus strain was positive for 3 resistance genes, and 4 other strains carried two of the target genes. Of the 6 antibiotic resistance genes detected in root canal strains, the most prevalent were blaTEM (17% of the strains), tetW (10%), and ermC (10%). Some as-yet-uncharacterized Fusobacterium and Prevotella isolates were positive for blaTEM, cfxA and tetM. Findings demonstrated that an unexpectedly large proportion of dental root canal isolates, including as-yet-uncharacterized strains previously regarded as uncultivated phylotypes, can carry antibiotic resistance genes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Profiling nematode communities in unmanaged flowerbed and agricultural field soils in Japan by DNA barcode sequencing.

    Directory of Open Access Journals (Sweden)

    Hisashi Morise

    Full Text Available Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU rDNA fragments were directly amplified from each of 68 (flowerbed samples and 48 (field samples isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs, indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis.

  1. Profiling Nematode Communities in Unmanaged Flowerbed and Agricultural Field Soils in Japan by DNA Barcode Sequencing

    Science.gov (United States)

    Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

    2012-01-01

    Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis. PMID:23284767

  2. Gene Expression Profiling and Identification of Resistance Genes to Aspergillus flavus Infection in Peanut through EST and Microarray Strategies

    Directory of Open Access Journals (Sweden)

    Baozhu Guo

    2011-06-01

    Full Text Available Aspergillus flavus and A. parasiticus infect peanut seeds and produce aflatoxins, which are associated with various diseases in domestic animals and humans throughout the world. The most cost-effective strategy to minimize aflatoxin contamination involves the development of peanut cultivars that are resistant to fungal infection and/or aflatoxin production. To identify peanut Aspergillus-interactive and peanut Aspergillus-resistance genes, we carried out a large scale peanut Expressed Sequence Tag (EST project which we used to construct a peanut glass slide oligonucleotide microarray. The fabricated microarray represents over 40% of the protein coding genes in the peanut genome. For expression profiling, resistant and susceptible peanut cultivars were infected with a mixture of Aspergillus flavus and parasiticus spores. The subsequent microarray analysis identified 62 genes in resistant cultivars that were up-expressed in response to Aspergillus infection. In addition, we identified 22 putative Aspergillus-resistance genes that were constitutively up-expressed in the resistant cultivar in comparison to the susceptible cultivar. Some of these genes were homologous to peanut, corn, and soybean genes that were previously shown to confer resistance to fungal infection. This study is a first step towards a comprehensive genome-scale platform for developing Aspergillus-resistant peanut cultivars through targeted marker-assisted breeding and genetic engineering.

  3. Unraveling flp-11/flp-32 dichotomy in nematodes.

    Science.gov (United States)

    Atkinson, Louise E; Miskelly, Iain R; Moffett, Christy L; McCoy, Ciaran J; Maule, Aaron G; Marks, Nikki J; Mousley, Angela

    2016-10-01

    FMRFamide-like peptide (FLP) signalling systems are core to nematode neuromuscular function. Novel drug discovery efforts associated with nematode FLP/FLP receptor biology are advanced through the accumulation of basic biological data that can reveal subtle complexities within the neuropeptidergic system. This study reports the characterisation of FMRFamide-like peptide encoding gene-11 (flp-11) and FMRFamide-like peptide encoding gene-32 (flp-32), two distinct flp genes which encode the analogous peptide, AMRN(A/S)LVRFamide, in multiple nematode species - the only known example of this phenomenon within the FLPergic system of nematodes. Using bioinformatics, in situ hybridisation, immunocytochemistry and behavioural assays we show that: (i) flp-11 and -32 are distinct flp genes expressed individually or in tandem across multiple nematode species, where they encode a highly similar peptide; (ii) flp-11 does not appear to be the most widely expressed flp in Caenorhabditis elegans; (iii) in species expressing both flp-11 and flp-32, flp-11 displays a conserved, restricted expression pattern across nematode clades and lifestyles; (iv) in species expressing both flp-11 and flp-32, flp-32 expression is more widespread and less conserved than flp-11; (v) in species expressing only flp-11, the flp-11 expression profile is more similar to the flp-32 profile observed in species expressing both; and (vi) FLP-11 peptides inhibit motor function in multiple nematode species. The biological significance and evolutionary origin of flp-11 and -32 peptide duplication remains unclear despite attempts to identify a common ancestor; this may become clearer as the availability of genomic data improves. This work provides insight into the complexity of the neuropeptidergic system in nematodes, and begins to examine how nematodes may compensate for structural neuronal simplicity. From a parasite control standpoint, this work underscores the importance of basic biological data, and has

  4. Alteration of gene expression and DNA methylation in drug-resistant gastric cancer.

    Science.gov (United States)

    Maeda, Osamu; Ando, Takafumi; Ohmiya, Naoki; Ishiguro, Kazuhiro; Watanabe, Osamu; Miyahara, Ryoji; Hibi, Yoko; Nagai, Taku; Yamada, Kiyofumi; Goto, Hidemi

    2014-04-01

    The mechanisms of drug resistance in cancer are not fully elucidated. To study the drug resistance of gastric cancer, we analyzed gene expression and DNA methylation profiles of 5-fluorouracil (5-FU)- and cisplatin (CDDP)-resistant gastric cancer cells and biopsy specimens. Drug-resistant gastric cancer cells were established with culture for >10 months in a medium containing 5-FU or CDDP. Endoscopic biopsy specimens were obtained from gastric cancer patients who underwent chemotherapy with oral fluoropyrimidine S-1 and CDDP. Gene expression and DNA methylation analyses were performed using microarray, and validated using real-time PCR and pyrosequencing, respectively. Out of 17,933 genes, 541 genes commonly increased and 569 genes decreased in both 5-FU- and CDDP-resistant AGS cells. Genes with expression changed by drugs were related to GO term 'extracellular region' and 'p53 signaling pathway' in both 5-FU- and CDDP-treated cells. Expression of 15 genes including KLK13 increased and 12 genes including ETV7 decreased, in both drug-resistant cells and biopsy specimens of two patients after chemotherapy. Out of 10,365 genes evaluated with both expression microarray and methylation microarray, 74 genes were hypermethylated and downregulated, or hypomethylated and upregulated in either 5-FU-resistant or CDDP-resistant cells. Of these genes, expression of 21 genes including FSCN1, CPT1C and NOTCH3, increased from treatment with a demethylating agent. There are alterations of gene expression and DNA methylation in drug-resistant gastric cancer; they may be related to mechanisms of drug resistance and may be useful as biomarkers of gastric cancer drug sensitivity.

  5. Class 1 and 2 integrons, sul resistance genes and antibiotic resistance in Escherichia coli isolated from Dongjiang River, South China

    International Nuclear Information System (INIS)

    Su Haochang; Ying Guangguo; Tao Ran; Zhang Ruiquan; Zhao Jianliang; Liu Yousheng

    2012-01-01

    Antibiotic susceptibility, detection of sul gene types and presence of class 1, 2 and 3 integrons and gene cassettes using PCR assays were investigated in 3456 Escherichia coli isolates obtained from 38 sampling sites of the Dongjiang River catchment in the dry and wet seasons. 89.1% of the isolates were resistant and 87.5% showed resistance to at least three antibiotics. sul2 was detected most frequently in 89.2% of 1403 SXT-resistant isolates. The presence of integrons (class 1 and 2) was frequently observed (82.3%) while no class 3 integron was found. In these integrons, 21 resistance genes of 14 gene cassette arrays and 10 different families of resistance genes were identified. Three gene cassette arrays, aac(6')-Ib-cr-aar-3-dfrA27-aadA16, aacA4-catB3-dfrA1 and aadA2-lnuF, were detected for the first time in surface water. The results showed that bacterial resistance in the catchment was seriously influenced by human activities, especially discharge of wastewater. Highlights: ► Antibiotic resistance was investigated for a river catchment of southern China. ► 87.5% of E coli isolates showed resistance to at least three antibiotics. ► The presence of integrons (class 1 and 2) was frequently observed (82.3%). ► Bacterial resistance in the catchment was seriously influenced by human activities. - Bacterial resistance to antibiotics in a catchment is related to the discharge of wastewater into the aquatic environment.

  6. Development of the system nematode, Ditylenchus Dipsaci (Kuehn) Filipjev, and the potato tuber nematode, D. Destructor thore, after gamma irradiation

    International Nuclear Information System (INIS)

    Ignatowicz, S.; Karnkowski, W.

    1996-01-01

    Juvenile and adult nematodes emerged from onion and garlic samples on the 3 rd week after irradiation with doses up to 0.5 kGy and from potato treated with doses up to 2.0 kGy. However, irradiation of onion infected with Ditylenchus dipsaci caused the inhibition of the development and growth of juvenile nematodes to mature forms. Doses of gamma radiation ranging from 0.1 to 0.5 kGy had only a slight effect, if any, on the development and growth of D. dipsaci nematodes infecting garlic, but they increased juvenile mortality. Gamma radiation at doses up to 2.0 kGy induced increased mortality of nematode juveniles of the potato tuber nematode, D. destructor but less so inhibited their development to mature forms. Nematodes were found to be resistant to irradiation treatment. Therefore the use of gamma irradiation for nematode disinfestation of agricultural products seems to be impractical, if the aim of the treatment is to kill these pests within a few weeks. The level of radiation required to kill nematodes in infected plants would damage plant tissues so that the further storage of vegetables will be impossible. (author). 22 refs, 3 figs, 2 tabs

  7. Phylogenetic relatedness determined between antibiotic resistance and 16S rRNA genes in actinobacteria.

    Science.gov (United States)

    Sagova-Mareckova, Marketa; Ulanova, Dana; Sanderova, Petra; Omelka, Marek; Kamenik, Zdenek; Olsovska, Jana; Kopecky, Jan

    2015-04-01

    Distribution and evolutionary history of resistance genes in environmental actinobacteria provide information on intensity of antibiosis and evolution of specific secondary metabolic pathways at a given site. To this day, actinobacteria producing biologically active compounds were isolated mostly from soil but only a limited range of soil environments were commonly sampled. Consequently, soil remains an unexplored environment in search for novel producers and related evolutionary questions. Ninety actinobacteria strains isolated at contrasting soil sites were characterized phylogenetically by 16S rRNA gene, for presence of erm and ABC transporter resistance genes and antibiotic production. An analogous analysis was performed in silico with 246 and 31 strains from Integrated Microbial Genomes (JGI_IMG) database selected by the presence of ABC transporter genes and erm genes, respectively. In the isolates, distances of erm gene sequences were significantly correlated to phylogenetic distances based on 16S rRNA genes, while ABC transporter gene distances were not. The phylogenetic distance of isolates was significantly correlated to soil pH and organic matter content of isolation sites. In the analysis of JGI_IMG datasets the correlation between phylogeny of resistance genes and the strain phylogeny based on 16S rRNA genes or five housekeeping genes was observed for both the erm genes and ABC transporter genes in both actinobacteria and streptomycetes. However, in the analysis of sequences from genomes where both resistance genes occurred together the correlation was observed for both ABC transporter and erm genes in actinobacteria but in streptomycetes only in the erm gene. The type of erm resistance gene sequences was influenced by linkage to 16S rRNA gene sequences and site characteristics. The phylogeny of ABC transporter gene was correlated to 16S rRNA genes mainly above the genus level. The results support the concept of new specific secondary metabolite

  8. Targeted mutagenesis in a human-parasitic nematode

    Science.gov (United States)

    Gang, Spencer S.; Castelletto, Michelle L.

    2017-01-01

    Parasitic nematodes infect over 1 billion people worldwide and cause some of the most common neglected tropical diseases. Despite their prevalence, our understanding of the biology of parasitic nematodes has been limited by the lack of tools for genetic intervention. In particular, it has not yet been possible to generate targeted gene disruptions and mutant phenotypes in any parasitic nematode. Here, we report the development of a method for introducing CRISPR-Cas9-mediated gene disruptions in the human-parasitic threadworm Strongyloides stercoralis. We disrupted the S. stercoralis twitchin gene unc-22, resulting in nematodes with severe motility defects. Ss-unc-22 mutations were resolved by homology-directed repair when a repair template was provided. Omission of a repair template resulted in deletions at the target locus. Ss-unc-22 mutations were heritable; we passed Ss-unc-22 mutants through a host and successfully recovered mutant progeny. Using a similar approach, we also disrupted the unc-22 gene of the rat-parasitic nematode Strongyloides ratti. Our results demonstrate the applicability of CRISPR-Cas9 to parasitic nematodes, and thereby enable future studies of gene function in these medically relevant but previously genetically intractable parasites. PMID:29016680

  9. Antibiotic Resistant Bacteria And Their Associated Resistance Genes in a Conventional Municipal Wastewater Treatment Plant

    KAUST Repository

    Aljassim, Nada I.

    2013-12-01

    With water scarcity as a pressing issue in Saudi Arabia and other Middle Eastern countries, the treatment and reuse of municipal wastewater is increasingly being used as an alternative water source to supplement country water needs. Standards are in place to ensure a safe treated wastewater quality, however they do not regulate pathogenic bacteria and emerging contaminants. Information is lacking on the levels of risk to public health associated with these factors, the efficiency of conventional treatment strategies in removing them, and on wastewater treatment in Saudi Arabia in general. In this study, a municipal wastewater treatment plant in Saudi Arabia is investigated to assess the efficiency of conventional treatment in meeting regulations and removing pathogens and emerging contaminants. The study found pathogenic bacterial genera, antibiotic resistance genes and antibiotic resistant bacteria, many of which were multi-resistant in plant discharges. It was found that although the treatments are able to meet traditional quality guidelines, there remains a risk from the discussed contaminants with wastewater reuse. A deeper understanding of this risk, and suggestions for more thorough guidelines and monitoring are needed.

  10. A Gene Homologous to rRNA Methylase Genes Confers Erythromycin and Clindamycin Resistance in Bifidobacterium breve.

    Science.gov (United States)

    Martínez, Noelia; Luque, Roberto; Milani, Christian; Ventura, Marco; Bañuelos, Oscar; Margolles, Abelardo

    2018-05-15

    Bifidobacteria are mutualistic intestinal bacteria, and their presence in the human gut has been associated with health-promoting activities. The presence of antibiotic resistance genes in this genus is controversial, since, although bifidobacteria are nonpathogenic microorganisms, they could serve as reservoirs of resistance determinants for intestinal pathogens. However, until now, few antibiotic resistance determinants have been functionally characterized in this genus. In this work, we show that Bifidobacterium breve CECT7263 displays atypical resistance to erythromycin and clindamycin. In order to delimit the genomic region responsible for the observed resistance phenotype, a library of genomic DNA was constructed and a fragment of 5.8 kb containing a gene homologous to rRNA methylase genes was able to confer erythromycin resistance in Escherichia coli This genomic region seems to be very uncommon, and homologs of the gene have been detected in only one strain of Bifidobacterium longum and two other strains of B. breve In this context, analysis of shotgun metagenomics data sets revealed that the gene is also uncommon in the microbiomes of adults and infants. The structural gene and its upstream region were cloned into a B. breve -sensitive strain, which became resistant after acquiring the genetic material. In vitro conjugation experiments did not allow us to detect gene transfer to other recipients. Nevertheless, prediction of genes potentially acquired through horizontal gene transfer events revealed that the gene is located in a putative genomic island. IMPORTANCE Bifidobacterium breve is a very common human intestinal bacterium. Often described as a pioneer microorganism in the establishment of early-life intestinal microbiota, its presence has been associated with several beneficial effects for the host, including immune stimulation and protection against infections. Therefore, some strains of this species are considered probiotics. In relation to this

  11. Plant-parasitic nematodes: towards understanding molecular players in stress responses.

    Science.gov (United States)

    Gillet, François-Xavier; Bournaud, Caroline; Antonino de Souza Júnior, Jose Dijair; Grossi-de-Sa, Maria Fatima

    2017-03-01

    Plant-parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant-nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence. Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1 , which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection. DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

  12. Fine mapping and identification of a candidate gene for the barley Un8 true loose smut resistance gene.

    Science.gov (United States)

    Zang, Wen; Eckstein, Peter E; Colin, Mark; Voth, Doug; Himmelbach, Axel; Beier, Sebastian; Stein, Nils; Scoles, Graham J; Beattie, Aaron D

    2015-07-01

    The candidate gene for the barley Un8 true loose smut resistance gene encodes a deduced protein containing two tandem protein kinase domains. In North America, durable resistance against all known isolates of barley true loose smut, caused by the basidiomycete pathogen Ustilago nuda (Jens.) Rostr. (U. nuda), is under the control of the Un8 resistance gene. Previous genetic studies mapped Un8 to the long arm of chromosome 5 (1HL). Here, a population of 4625 lines segregating for Un8 was used to delimit the Un8 gene to a 0.108 cM interval on chromosome arm 1HL, and assign it to fingerprinted contig 546 of the barley physical map. The minimal tilling path was identified for the Un8 locus using two flanking markers and consisted of two overlapping bacterial artificial chromosomes. One gene located close to a marker co-segregating with Un8 showed high sequence identity to a disease resistance gene containing two kinase domains. Sequence of the candidate gene from the parents of the segregating population, and in an additional 19 barley lines representing a broader spectrum of diversity, showed there was no intron in alleles present in either resistant or susceptible lines, and fifteen amino acid variations unique to the deduced protein sequence in resistant lines differentiated it from the deduced protein sequences in susceptible lines. Some of these variations were present within putative functional domains which may cause a loss of function in the deduced protein sequences within susceptible lines.

  13. Identification and characterization of two novel bla(KLUC resistance genes through large-scale resistance plasmids sequencing.

    Directory of Open Access Journals (Sweden)

    Teng Xu

    Full Text Available Plasmids are important antibiotic resistance determinant carriers that can disseminate various drug resistance genes among species or genera. By using a high throughput sequencing approach, two groups of plasmids of Escherichia coli (named E1 and E2, each consisting of 160 clinical E. coli strains isolated from different periods of time were sequenced and analyzed. A total of 20 million reads were obtained and mapped onto the known resistance gene sequences. As a result, a total of 9 classes, including 36 types of antibiotic resistant genes, were identified. Among these genes, 25 and 27 single nucleotide polymorphisms (SNPs appeared, of which 9 and 12 SNPs are nonsynonymous substitutions in the E1 and E2 samples. It is interesting to find that a novel genotype of bla(KLUC, whose close relatives, bla(KLUC-1 and bla(KLUC-2, have been previously reported as carried on the Kluyvera cryocrescens chromosome and Enterobacter cloacae plasmid, was identified. It shares 99% and 98% amino acid identities with Kluc-1 and Kluc-2, respectively. Further PCR screening of 608 Enterobacteriaceae family isolates yielded a second variant (named bla(KLUC-4. It was interesting to find that Kluc-3 showed resistance to several cephalosporins including cefotaxime, whereas bla(KLUC-4 did not show any resistance to the antibiotics tested. This may be due to a positively charged residue, Arg, replaced by a neutral residue, Leu, at position 167, which is located within an omega-loop. This work represents large-scale studies on resistance gene distribution, diversification and genetic variation in pooled multi-drug resistance plasmids, and provides insight into the use of high throughput sequencing technology for microbial resistance gene detection.

  14. Two whitebacked planthopper resistance genes in rice share the same loci with those for brown planthopper resistance.

    Science.gov (United States)

    Tan, G X; Weng, Q M; Ren, X; Huang, Z; Zhu, L L; He, G C

    2004-03-01

    The whitebacked planthopper (WBPH), Sogatella furcifera, and brown planthopper (BPH) Nilaparvata lugens Stål are important sucking insects of rice (Oryza sativa L.) crops throughout the world. Rice 'B5', which has derived its resistance genes from the wild rice O. officinalis Wall ex Watt, is a line that is highly resistant to both WBPH and BPH. Previously, two resistance genes against BPH, Qbp1, and Qbp2 in 'B5' had been mapped onto chromosome 3 and chromosome 4, respectively. In this study, we employed a mapping population composed of 187 recombinant inbred lines (RILs), produced from a cross between 'B5' and susceptible variety 'Minghui63', to locate the WBPH and BPH resistance genes. A RFLP survey of the bulked extremes from the RIL population identified two genomic regions, one on chromosome 3 and the other on chromosome 4, likely containing the resistance genes to planthoppers. QTL analysis of the RILs further confirmed that two WBPH resistance genes were mapped on the same loci as Qbp1 and Qbp2, using a linkage map with 242 molecular markers distributed on 12 rice chromosomes. Of the two WBPH resistance genes, one designated Wbph7(t) was located within a 1.1-cM region between R1925 and G1318 on chromosome 3, the other designated Wbph8(t) was within a 0.3-cM region flanked by R288 and S11182 on chromosome 4. A two-way analysis of variance showed that two loci acted independently with each other in determining WBPH resistance. The results have significant implications in studying the interactions between sucking insects and plants and in breeding programs of resistance to rice planthoppers.

  15. Phylogenetic relationships of some spirurine nematodes (Nematoda: Chromadorea: Rhabditida: Spirurina) parasitic in fishes inferred from SSU rRNA gene sequences.

    Science.gov (United States)

    Cernotíková, Eva; Horák, Ales; Moravec, Frantisek

    2011-06-01

    Abstract: Small subunit rRNA sequences were obtained from 38 representatives mainly of the nematode orders Spirurida (Camallanidae, Cystidicolidae, Daniconematidae, Philometridae, Physalopteridae, Rhabdochonidae, Skrjabillanidae) and, in part, Ascaridida (Anisakidae, Cucullanidae, Quimperiidae). The examined nematodes are predominantly parasites of fishes. Their analyses provided well-supported trees allowing the study ofphylogenetic relationships among some spirurine nematodes. The present results support the placement of Cucullanidae at the base of the suborder Spirurina and, based on the position of the genus Philonema (subfamily Philoneminae) forming a sister group to Skrjabillanidae (thus Philoneminae should be elevated to Philonemidae), the paraphyly of the Philometridae. Comparison of a large number of sequences of representatives of the latter family supports the paraphyly of the genera Philometra, Philometroides and Dentiphilometra. The validity of the newly included genera Afrophilometra and Caranginema is not supported. These results indicate geographical isolation has not been the cause of speciation in this parasite group and no coevolution with fish hosts is apparent. On the contrary, the group of South-American species ofAlinema, Nilonema and Rumai is placed in an independent branch, thus markedly separated from other family members. Molecular data indicate that the skrjabillanid subfamily Esocineminae (represented by Esocinema bohemicum) should be either elevated to the rank of an independent family or Daniconematidae (Mexiconema africanum) should be decreased to Daniconematinae and transferred to the family Skrjabillanidae. Camallanid genera Camallanus and Procamallanus, as well as the subgenera Procamallanus and Spirocamallanus are confirmed to be paraphyletic. Paraphyly has also been found within Filarioidea, Habronematoidea and Thelazioidea and in Cystidicolidae, Physalopteridae and Thelaziidae. The results of the analyses also show that

  16. Sulfonamide-resistant bacteria and their resistance genes in soils fertilized with manures from Jiangsu Province, Southeastern China.

    Directory of Open Access Journals (Sweden)

    Na Wang

    Full Text Available Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (p<0.05. The combination of sul1 and sul2 was the most frequent, and the co-existence of sul1 and sul3 was not found either in the genomic DNA or plasmids. The sample type, animal type and sampling time can influence the prevalence and distribution pattern of sulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China.

  17. Comparison of constitutive and thiabendazole-induced expression of five cytochrome P450 genes in fourth-stage larvae of Haemonchus contortus isolates with different drug susceptibility identifies one gene with high constitutive expression in a multi-resistant isolate

    Directory of Open Access Journals (Sweden)

    Esra Yilmaz

    2017-12-01

    Full Text Available Benzimidazoles (BZs remain amongst the most widely used anthelmintic drug classes against gastro-intestinal nematode infections, although their efficacy is increasingly compromised by resistance. The primary underlying mechanisms for BZ resistance are single-nucleotide polymorphisms (SNPs in the isotype 1 β-tubulin gene causing the substitutions F167Y, E198A or F200Y. However, resistance is believed to be multi-genic and previous studies have shown that isolates carrying 90–100% F200Y can vary considerably in their resistance level in the egg hatch assay (EHA. Cytochrome P450 monooxygenases (CYPs are associated with drug resistance in mammals and arthropods and have been considered as mediators of anthelmintic resistance. In Caenorhabditis elegans, several members of the CYP34/35 and CYP31 families are BZ and/or xenobiotic inducible and thiabendazole (TBZ is metabolised by CYP35D1. Here, expression of all 5 CYPs closely related to the C. elegans CYP34/35 and CYP31 families was investigated in fourth-stage larvae of two susceptible and three BZ-resistant Haemonchus contortus isolates following in vitro exposure to TBZ for 3 and 6 h using real-time RT-PCR. The resistance status of all isolates was determined using EHAs and quantification of resistance-associated β-tubulin SNPs using pyrosequencing. While none of the CYPs was TBZ inducible, constitutive expression of CYP34/35 family member HCOI100383400 was significantly 2.4–3.7-fold higher in the multi-drug resistant WR isolate with the strongest BZ resistance phenotype compared to susceptible and intermediate-level BZ-resistant isolates. Although this increase is only moderate, HCOI100383400 might still be involved in high-level BZ resistance by further decreasing susceptibility in isolates already carrying 100% of a β-tubulin SNP causing BZ resistance. Lower transcript levels were observed for all CYPs in the intermediately resistant IRE isolate in comparison to the susceptible Hc

  18. Dissection of Resistance Genes to Pseudomonas syringae pv. phaseolicola in UI3 Common Bean Cultivar.

    Science.gov (United States)

    González, Ana M; Godoy, Luís; Santalla, Marta

    2017-11-23

    Few quantitative trait loci have been mapped for resistance to Pseudomonas syringae pv. phaseolicola in common bean. Two F₂ populations were developed from the host differential UI3 cultivar. The objective of this study was to further characterize the resistance to races 1, 5, 7 and 9 of Psp included in UI3. Using a QTL mapping approach, 16 and 11 main-effect QTLs for pod and primary leaf resistance were located on LG10, explaining up to 90% and 26% of the phenotypic variation, respectively. The homologous genomic region corresponding to primary leaf resistance QTLs detected tested positive for the presence of resistance-associated gene cluster encoding nucleotide-binding and leucine-rich repeat (NL), Natural Resistance Associated Macrophage (NRAMP) and Pentatricopeptide Repeat family (PPR) proteins. It is worth noting that the main effect QTLs for resistance in pod were located inside a 3.5 Mb genomic region that included the Phvul.010G021200 gene, which encodes a protein that has the highest sequence similarity to the RIN4 gene of Arabidopsis, and can be considered an important candidate gene for the organ-specific QTLs identified here. These results support that resistance to Psp from UI3 might result from the immune response activated by combinations of R proteins, and suggest the guard model as an important mechanism in pod resistance to halo blight. The candidate genes identified here warrant functional studies that will help in characterizing the actual defense gene(s) in UI3 genotype.

  19. Natural variation of rice blast resistance gene Pi-d2

    Science.gov (United States)

    Studying natural variation of rice resistance (R) genes in cultivated and wild rice relatives can predict resistance stability to rice blast fungus. In the present study, the protein coding regions of rice R gene Pi-d2 in 35 rice accessions of subgroups, aus (AUS), indica (IND), temperate japonica (...

  20. Transport and transformation of genetic information in the critical zone: The case of antibiotic resistance genes

    Science.gov (United States)

    Zhu, Y. G.

    2015-12-01

    In addition to material and energy flows, the dynamics and functions of the Earth's critical zone are intensively mediated by biological actions performed by diverse organisms. These biological actions are modulated by the expression of functional genes and their translation into enzymes that catalyze geochemical reactions, such as nutrient turnover and pollutant biodegradation. Although geobiology, as an interdisciplinary research area, is playing and vital role in linking biological and geochemical processes at different temporal and spatial scales, the distribution and transport of functional genes have rarely been investigated from the Earth's critical zone perspectives. To illustrate the framework of studies on the transport and transformation of genetic information in the critical zone, antibiotic resistance is taken as an example. Antibiotic resistance genes are considered as a group of emerging contaminants, and their emergence and spread within the critical zone on one hand are induced by anthropogenic activities, and on other hand are threatening human health worldwide. The transport and transformation of antibiotic resistance genes are controlled by both horizontal gene transfer between bacterial cells and the movement of bacteria harboring antibiotic resistance genes. In this paper, the fate and behavior of antibiotic resistance genes will be discussed in the following aspects: 1) general overview of environmental antibiotic resistance; 2) high through quantification of the resistome in various environmental media; 3) pathways of resistance gene flow within the critical zone; and 4) potential strategies in mitigating antibiotic resistance, particularly from the critical zone perspectives.

  1. Molecular characterization of the CRa gene conferring clubroot resistance in Brassica rapa.

    Science.gov (United States)

    Ueno, Hiroki; Matsumoto, Etsuo; Aruga, Daisuke; Kitagawa, Satoshi; Matsumura, Hideo; Hayashida, Nobuaki

    2012-12-01

    Clubroot disease is one of the major diseases affecting Brassicaceae crops, and a number of these crops grown commercially, such as Chinese cabbage (Brassica rapa L. ssp. pekinensis), are known to be highly susceptible to clubroot disease. To provide protection from this disease, plant breeders have introduced genes for resistance to clubroot from the European turnip into susceptible lines. The CRa gene confers specific resistance to the clubroot pathogen Plasmodiophora brassicae isolate M85. Fine mapping of the CRa locus using synteny to the Arabidopsis thaliana genome and partial genome sequences of B. rapa revealed a candidate gene encoding a TIR-NBS-LRR protein. Several structural differences in this candidate gene were found between susceptible and resistant lines, and CRa expression was observed only in the resistant line. Four mutant lines lacking clubroot resistance were obtained by the UV irradiation of pollen from a resistant line, and all of these mutant lines carried independent mutations in the candidate TIR-NBS-LRR gene. This genetic and molecular evidence strongly suggests that the identified gene is CRa. This is the first report on the molecular characterization of a clubroot Resistance gene in Brassicaceae and of the disease resistance gene in B. rapa.

  2. An AFLP marker linked to turnip mosaic virus resistance gene in pak ...

    African Journals Online (AJOL)

    An AFLP marker linked to turnip mosaic virus resistance gene in pak-choi. W Xinhua, C Huoying, Z Yuying, H Ruixian. Abstract. Pak-choi is one of the most important vegetable crops in China. Turnip mosaic virus (TuMV) is one of its main pathogen. Screening the molecular marker linked to the TuMV resistance gene is an ...

  3. Identification of leaf rust resistant gene Lr10 in Pakistani wheat ...

    African Journals Online (AJOL)

    Leaf (brown) rust is the major disease of wheat in Pakistan and other countries. The disease is more effectively controlled when several rust resistance genes are pyramided into a single line. Molecular survey was conducted to screen 25 Pakistan wheat germplasm for the presence of leaf rust resistance gene Lr10 using ...

  4. Identifying clinically relevant drug resistance genes in drug-induced resistant cancer cell lines and post-chemotherapy tissues.

    Science.gov (United States)

    Tong, Mengsha; Zheng, Weicheng; Lu, Xingrong; Ao, Lu; Li, Xiangyu; Guan, Qingzhou; Cai, Hao; Li, Mengyao; Yan, Haidan; Guo, You; Chi, Pan; Guo, Zheng

    2015-12-01

    Until recently, few molecular signatures of drug resistance identified in drug-induced resistant cancer cell models can be translated into clinical practice. Here, we defined differentially expressed genes (DEGs) between pre-chemotherapy colorectal cancer (CRC) tissue samples of non-responders and responders for 5-fluorouracil and oxaliplatin-based therapy as clinically relevant drug resistance genes (CRG5-FU/L-OHP). Taking CRG5-FU/L-OHP as reference, we evaluated the clinical relevance of several types of genes derived from HCT116 CRC cells with resistance to 5-fluorouracil and oxaliplatin, respectively. The results revealed that DEGs between parental and resistant cells, when both were treated with the corresponding drug for a certain time, were significantly consistent with the CRG5-FU/L-OHP as well as the DEGs between the post-chemotherapy CRC specimens of responders and non-responders. This study suggests a novel strategy to extract clinically relevant drug resistance genes from both drug-induced resistant cell models and post-chemotherapy cancer tissue specimens.

  5. The expression of antibiotic resistance genes in antibiotic-producing bacteria.

    Science.gov (United States)

    Mak, Stefanie; Xu, Ye; Nodwell, Justin R

    2014-08-01

    Antibiotic-producing bacteria encode antibiotic resistance genes that protect them from the biologically active molecules that they produce. The expression of these genes needs to occur in a timely manner: either in advance of or concomitantly with biosynthesis. It appears that there have been at least two general solutions to this problem. In many cases, the expression of resistance genes is tightly linked to that of antibiotic biosynthetic genes. In others, the resistance genes can be induced by their cognate antibiotics or by intermediate molecules from their biosynthetic pathways. The regulatory mechanisms that couple resistance to antibiotic biosynthesis are mechanistically diverse and potentially relevant to the origins of clinical antibiotic resistance. © 2014 John Wiley & Sons Ltd.

  6. Isolation and characterization of NBS-LRR- resistance gene candidates in turmeric (Curcuma longa cv. surama).

    Science.gov (United States)

    Joshi, R K; Mohanty, S; Subudhi, E; Nayak, S

    2010-09-08

    Turmeric (Curcuma longa), an important asexually reproducing spice crop of the family Zingiberaceae is highly susceptible to bacterial and fungal pathogens. The identification of resistance gene analogs holds great promise for development of resistant turmeric cultivars. Degenerate primers designed based on known resistance genes (R-genes) were used in combinations to elucidate resistance gene analogs from Curcuma longa cultivar surama. The three primers resulted in amplicons with expected sizes of 450-600 bp. The nucleotide sequence of these amplicons was obtained through sequencing; their predicted amino acid sequences compared to each other and to the amino acid sequences of known R-genes revealed significant sequence similarity. The finding of conserved domains, viz., kinase-1a, kinase-2 and hydrophobic motif, provided evidence that the sequences belong to the NBS-LRR class gene family. The presence of tryptophan as the last residue of kinase-2 motif further qualified them to be in the non-TIR-NBS-LRR subfamily of resistance genes. A cluster analysis based on the neighbor-joining method was carried out using Curcuma NBS analogs together with several resistance gene analogs and known R-genes, which classified them into two distinct subclasses, corresponding to clades N3 and N4 of non-TIR-NBS sequences described in plants. The NBS analogs that we isolated can be used as guidelines to eventually isolate numerous R-genes in turmeric.

  7. Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1 from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi.

    Directory of Open Access Journals (Sweden)

    Fen Qiao

    Full Text Available Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266, Ha-far-2 (KU877267, Hf-far-1 (KU877268. Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more

  8. Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1) from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi.

    Science.gov (United States)

    Qiao, Fen; Luo, Lilian; Peng, Huan; Luo, Shujie; Huang, Wenkun; Cui, Jiangkuan; Li, Xin; Kong, Lingan; Jiang, Daohong; Chitwood, David J; Peng, Deliang

    2016-01-01

    Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR) proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266), Ha-far-2 (KU877267), Hf-far-1 (KU877268). Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more than Ha-far-2 in

  9. Mapping, isolation and characterization of genes responsible for late blight resistance in potato

    NARCIS (Netherlands)

    Pel, M.

    2010-01-01

    Late blight (LB), caused by the oomycete Phytophthora infestans, is one of the most
    devastating diseases on potato. Resistance (R) genes from the wild species Solanum demissum
    have been used by breeders to generate late blight resistant cultivars, but resistance was soon
    overcome

  10. In Silico Assigned Resistance Genes Confer Bifidobacterium with Partial Resistance to Aminoglycosides but Not to Β-Lactams

    Science.gov (United States)

    Fouhy, Fiona; O’Connell Motherway, Mary; Fitzgerald, Gerald F.; Ross, R. Paul; Stanton, Catherine; van Sinderen, Douwe; Cotter, Paul D.

    2013-01-01

    Bifidobacteria have received significant attention due to their contribution to human gut health and the use of specific strains as probiotics. It is thus not surprising that there has also been significant interest with respect to their antibiotic resistance profile. Numerous culture-based studies have demonstrated that bifidobacteria are resistant to the majority of aminoglycosides, but are sensitive to β-lactams. However, limited research exists with respect to the genetic basis for the resistance of bifidobacteria to aminoglycosides. Here we performed an in-depth in silico analysis of putative Bifidobacterium-encoded aminoglycoside resistance proteins and β-lactamases and assess the contribution of these proteins to antibiotic resistance. The in silico-based screen detected putative aminoglycoside and β-lactam resistance proteins across the Bifidobacterium genus. Laboratory-based investigations of a number of representative bifidobacteria strains confirmed that despite containing putative β-lactamases, these strains were sensitive to β-lactams. In contrast, all strains were resistant to the aminoglycosides tested. To assess the contribution of genes encoding putative aminoglycoside resistance proteins in Bifidobacterium sp. two genes, namely Bbr_0651 and Bbr_1586, were targeted for insertional inactivation in B. breve UCC2003. As compared to the wild-type, the UCC2003 insertion mutant strains exhibited decreased resistance to gentamycin, kanamycin and streptomycin. This study highlights the associated risks of relying on the in silico assignment of gene function. Although several putative β-lactam resistance proteins are located in bifidobacteria, their presence does not coincide with resistance to these antibiotics. In contrast however, this approach has resulted in the identification of two loci that contribute to the aminoglycoside resistance of B. breve UCC2003 and, potentially, many other bifidobacteria. PMID:24324818

  11. In silico assigned resistance genes confer Bifidobacterium with partial resistance to aminoglycosides but not to β-lactams.

    Directory of Open Access Journals (Sweden)

    Fiona Fouhy

    Full Text Available Bifidobacteria have received significant attention due to their contribution to human gut health and the use of specific strains as probiotics. It is thus not surprising that there has also been significant interest with respect to their antibiotic resistance profile. Numerous culture-based studies have demonstrated that bifidobacteria are resistant to the majority of aminoglycosides, but are sensitive to β-lactams. However, limited research exists with respect to the genetic basis for the resistance of bifidobacteria to aminoglycosides. Here we performed an in-depth in silico analysis of putative Bifidobacterium-encoded aminoglycoside resistance proteins and β-lactamases and assess the contribution of these proteins to antibiotic resistance. The in silico-based screen detected putative aminoglycoside and β-lactam resistance proteins across the Bifidobacterium genus. Laboratory-based investigations of a number of representative bifidobacteria strains confirmed that despite containing putative β-lactamases, these strains were sensitive to β-lactams. In contrast, all strains were resistant to the aminoglycosides tested. To assess the contribution of genes encoding putative aminoglycoside resistance proteins in Bifidobacterium sp. two genes, namely Bbr_0651 and Bbr_1586, were targeted for insertional inactivation in B. breve UCC2003. As compared to the wild-type, the UCC2003 insertion mutant strains exhibited decreased resistance to gentamycin, kanamycin and streptomycin. This study highlights the associated risks of relying on the in silico assignment of gene function. Although several putative β-lactam resistance proteins are located in bifidobacteria, their presence does not coincide with resistance to these antibiotics. In contrast however, this approach has resulted in the identification of two loci that contribute to the aminoglycoside resistance of B. breve UCC2003 and, potentially, many other bifidobacteria.

  12. The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Petersen, Andreas

    2007-01-01

    Objectives: To determine the genetic basis for tetracycline and sulphonamide resistance and the prevalence of class I and II integrons in oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Methods: A total of 222 isolates were screened for tetracycline resistance...... and Southern blots with sulII and tet(39) probes were performed on selected isolates. Results: The recently identified tetracycline resistance gene tet(39) was demonstrated in 75% (166/222) of oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Isolates that were also...

  13. Incorporation of Bacterial Blight Resistance Genes Into Lowland Rice Cultivar Through Marker-Assisted Backcross Breeding.

    Science.gov (United States)

    Pradhan, Sharat Kumar; Nayak, Deepak Kumar; Pandit, Elssa; Behera, Lambodar; Anandan, Annamalai; Mukherjee, Arup Kumar; Lenka, Srikanta; Barik, Durga Prasad

    2016-07-01

    Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in many rice growing countries. Pyramided lines carrying two BB resistance gene combinations (Xa21+xa13 and Xa21+xa5) were developed in a lowland cultivar Jalmagna background through backcross breeding by integrating molecular markers. In each backcross generation, markers closely linked to the disease resistance genes were used to select plants possessing the target genes. Background selection was continued in those plants carrying resistant genes until BC(3) generation. Plants having the maximum contribution from the recurrent parent genome were selected in each generation and hybridized with the recipient parent. The BB-pyramided line having the maximum recipient parent genome recovery of 95% was selected among BC3F1 plants and selfed to isolate homozygous BC(3)F(2) plants with different combinations of BB resistance genes. Twenty pyramided lines with two resistance gene combinations exhibited high levels of tolerance against the BB pathogen. In order to confirm the resistance, the pyramided lines were inoculated with different X. oryzae pv. oryzae strains of Odisha for bioassay. The genotypes with combination of two BB resistance genes conferred high levels of resistance to the predominant X. oryzae pv. oryzae isolates prevalent in the region. The pyramided lines showed similarity with the recipient parent with respect to major agro-morphologic traits.

  14. Molecular Identification and Quantification of Tetracycline and Erythromycin Resistance Genes in Spanish and Italian Retail Cheeses

    Directory of Open Access Journals (Sweden)

    Ana Belén Flórez

    2014-01-01

    Full Text Available Large antibiotic resistance gene pools in the microbiota of foods may ultimately pose a risk for human health. This study reports the identification and quantification of tetracycline- and erythromycin-resistant populations, resistance genes, and gene diversity in traditional Spanish and Italian cheeses, via culturing, conventional PCR, real-time quantitative PCR (qPCR, and denaturing gradient gel electrophoresis (DGGE. The numbers of resistant bacteria varied widely among the antibiotics and the different cheese varieties; in some cheeses, all the bacterial populations seemed to be resistant. Up to eight antibiotic resistance genes were sought by gene-specific PCR, six with respect to tetracycline, that is, tet(K, tet(L, tet(M, tet(O, tet(S, and tet(W, and two with respect to erythromycin, that is, erm(B and erm(F. The most common resistance genes in the analysed cheeses were tet(S, tet(W, tet(M, and erm(B. The copy numbers of these genes, as quantified by qPCR, ranged widely between cheeses (from 4.94 to 10.18log⁡10/g. DGGE analysis revealed distinct banding profiles and two polymorphic nucleotide positions for tet(W-carrying cheeses, though the similarity of the sequences suggests this tet(W to have a monophyletic origin. Traditional cheeses would therefore appear to act as reservoirs for large numbers of many types of antibiotic resistance determinants.

  15. Effective genes for resistance to stripe rust and virulence of Puccinia ...

    African Journals Online (AJOL)

    The results revealed that stripe rust resistance genes Yr3, Yr5, Yr10, Yr15, Yr26, YrSP and YrCV were resistant, while Yr18 showed moderate susceptibility at all locations. Genes YrA-, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr27 and gene combinations Opata (Yr27+Yr18) and Super Kauz (Yr9, Yr27, Yr18) were found susceptible.

  16. Genetics and mapping of a new leaf rust resistance gene in Triticum ...

    Indian Academy of Sciences (India)

    Genetic analysis in F1, F2 and F2.3 families at the seedling stage revealed that leaf rust resistance in Selection G12 is conditioned by a single incompletely dominant gene. The leaf rust resistance gene was mapped to chromosome 3BL with SSR markers Xgwm114 and Xgwm547 flanking the gene at a distance of 28.3 cM ...

  17. Genetic mapping of the rice resistance-breaking gene of the brown planthopper Nilaparvata lugens.

    Science.gov (United States)

    Kobayashi, Tetsuya; Yamamoto, Kimiko; Suetsugu, Yoshitaka; Kuwazaki, Seigo; Hattori, Makoto; Jairin, Jirapong; Sanada-Morimura, Sachiyo; Matsumura, Masaya

    2014-07-22

    Host plant resistance has been widely used for controlling the major rice pest brown planthopper (BPH, Nilaparvata lugens). However, adaptation of the wild BPH population to resistance limits the effective use of resistant rice varieties. Quantitative trait locus (QTL) analysis was conducted to identify resistance-breaking genes against the anti-feeding mechanism mediated by the rice resistance gene Bph1. QTL analysis in iso-female BPH lines with single-nucleotide polymorphism (SNP) markers detected a single region on the 10th linkage group responsible for the virulence. The QTL explained from 57 to 84% of the total phenotypic variation. Bulked segregant analysis with next-generation sequencing in F2 progenies identified five SNPs genetically linked to the virulence. These analyses showed that virulence to Bph1 was controlled by a single recessive gene. In contrast to previous studies, the gene-for-gene relationship between the major resistance gene Bph1 and virulence gene of BPH was confirmed. Identified markers are available for map-based cloning of the major gene controlling BPH virulence to rice resistance. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Characterization of resistance to tetracyclines and aminoglycosides of sheep mastitis pathogens: study of the effect of gene content on resistance.

    Science.gov (United States)

    Lollai, S A; Ziccheddu, M; Duprè, I; Piras, D

    2016-10-01

    Mastitis causes economic losses and antimicrobials are frequently used for mastitis treatment. Antimicrobial resistance surveys are still rare in the ovine field and characterization of strains is important in order to acquire information about resistance and for optimization of therapy. Bacterial pathogens recovered in milk samples from mastitis-affected ewes were characterized for resistance to tetracyclines and aminoglycosides, members of which are frequently used antimicrobials in small ruminants. A total of 185 strains of staphylococci, streptococci, and enterococci, common mastitis pathogens, were tested for minimal inhibitory concentration (MIC) to tetracycline, doxycycline, minocycline, gentamicin, kanamycin, streptomycin, and for resistance genes by PCR. Effects of different tet genes arrangements on MICs were also investigated. Staphylococci expressed the lowest MIC for tetracycline and tet(K) was the most common gene recovered; tet(M) and tet(O) were also found. Gene content was shown to influence the tetracycline MIC values. Enterococci and streptococci showed higher MICs to tetracyclines and nonsusceptible strains always harboured at least one ribosomal protection gene (MIC above 8 μg ml(-1) ). Streptococci often harboured two or more tet determinants. As regards the resistance to aminoglycosides, staphylococci showed the lowest gentamicin and kanamycin median MIC along with streptomycin high level resistant (HLR) strains (MIC >1024 μg ml(-1) ) all harbouring str gene. The resistance determinant aac(6')-Ie-aph(2″)-Ia was present in few strains. Streptococci were basically nonsusceptible to aminoglycosides but neither HLR isolates nor resistance genes were detected. Enterococci revealed the highest MICs for gentamicin; two str harbouring isolates were shown to be HLR to streptomycin. Evidence was obtained for the circulation of antimicrobial-resistant strains and genes in sheep dairy farming. Tetracycline MIC of 64 μg ml(-1) and high

  19. RNAi validation of resistance genes and their interactions in the highly DDT-resistant 91-R strain of Drosophila melanogaster.

    Science.gov (United States)

    Gellatly, Kyle J; Yoon, Kyong Sup; Doherty, Jeffery J; Sun, Weilin; Pittendrigh, Barry R; Clark, J Marshall

    2015-06-01

    4,4'-dichlorodiphenyltrichloroethane (DDT) has been re-recommended by the World Health Organization for malaria mosquito control. Previous DDT use has resulted in resistance, and with continued use resistance will increase in terms of level and extent. Drosophila melanogaster is a model dipteran that has many available genetic tools, numerous studies done on insecticide resistance mechanisms, and is related to malaria mosquitoes allowing for extrapolation. The 91-R strain of D. melanogaster is highly resistant to DDT (>1500-fold), however, there is no mechanistic scheme that accounts for this level of resistance. Recently, reduced penetration, increased detoxification, and direct excretion have been identified as resistance mechanisms in the 91-R strain. Their interactions, however, remain unclear. Use of UAS-RNAi transgenic lines of D. melanogaster allowed for the targeted knockdown of genes putatively involved in DDT resistance and has validated the role of several cuticular proteins (Cyp4g1 and Lcp1), cytochrome P450 monooxygenases (Cyp6g1 and Cyp12d1), and ATP binding cassette transporters (Mdr50, Mdr65, and Mrp1) involved in DDT resistance. Further, increased sensitivity to DDT in the 91-R strain after intra-abdominal dsRNA injection for Mdr50, Mdr65, and Mrp1 was determined by a DDT contact bioassay, directly implicating these genes in DDT efflux and resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Detection and Characterizations of Genes Resistant to Tetracycline and Sulfa among the Bacteria in Mariculture Water

    Science.gov (United States)

    Qu, L.; Li, Y.; Zhu, P.

    2013-12-01

    One hundred and thirty-five bacteria from maricultural environments were tested for sensitivity to tetracycline and sulfa. Result show that 72% of the bacteria were sulfa-resistant, 36% of the bacteria were tetracycline-resistant, and 16.5% of bacteria showed resistance to both tetracyclines and sulfa ,indicating that the proportion of sulfa and tetracycline resistance bacteria isvery large in the maricultural environments. PCR methods were used to detect if these resistant bacteria carry tetracycline and sulfa resistance genes. Out of the 33 tetracycline-resistant bacteria screened, 3 were positive for tetA, 6 were positive for tetB and no isolate wasboth positive for tetA and tetB. Of the 97 sulfa-resistant bacteria screened, 9 were positive for sul2, 6 were positive for sul1, 1 isolate was positive for bothsul1 and sul2. The minimum inhibitory concentration (MIC) of tetracycline for tetA-carrying isolates were higher than those tetB-carrying isolates.while The MIC of sulfa for sul2-carrying isolates were higher than those sul1-carrying isolates. Indicating that tetA and sul2 gene may play ubknown roles in resisting tetracycline and sulfa than tetB and sul1 genes. The results showed the 4 kinds of genes (tetA,tetB,sul1,sul2) has no host specificity. All these 16S sequence are from the isolates which are positive for the above genes, it indicated the above antibiotic resistance genes are widespread in the environment regardless of the host. While the DNA sequence of these four genes showed tetA, sul1, sul2 genes are conservative in different bacteria , etB gene conserved poorly. The research aim is to get a preliminary understanding of resistance mechanism related to the resistant bacteria and the resistance genes in marine aquaculture environment through the analysis of resistant genes, providing research base for the prevention and treatment of drug-resistant bacteria so as to reduce the threat to the ecological environment, aquaculture and human health.

  1. The genome of the yellow potato cyst nematode, Globodera rostochiensis, reveals insights into the basis of parasitism and virulence.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Laetsch, Dominik R; Thorpe, Peter; Lilley, Catherine J; Danchin, Etienne G J; Da Rocha, Martine; Rancurel, Corinne; Holroyd, Nancy E; Cotton, James A; Szitenberg, Amir; Grenier, Eric; Montarry, Josselin; Mimee, Benjamin; Duceppe, Marc-Olivier; Boyes, Ian; Marvin, Jessica M C; Jones, Laura M; Yusup, Hazijah B; Lafond-Lapalme, Joël; Esquibet, Magali; Sabeh, Michael; Rott, Michael; Overmars, Hein; Finkers-Tomczak, Anna; Smant, Geert; Koutsovoulos, Georgios; Blok, Vivian; Mantelin, Sophie; Cock, Peter J A; Phillips, Wendy; Henrissat, Bernard; Urwin, Peter E; Blaxter, Mark; Jones, John T

    2016-06-10

    The yellow potato cyst nematode, Globodera rostochiensis, is a devastating plant pathogen of global economic importance. This biotrophic parasite secretes effectors from pharyngeal glands, some of which were acquired by horizontal gene transfer, to manipulate host processes and promote parasitism. G. rostochiensis is classified into pathotypes with different plant resistance-breaking phenotypes. We generate a high quality genome assembly for G. rostochiensis pathotype Ro1, identify putative effectors and horizontal gene transfer events, map gene expression through the life cycle focusing on key parasitic transitions and sequence the genomes of eight populations including four additional pathotypes to identify variation. Horizontal gene transfer contributes 3.5 % of the predicted genes, of which approximately 8.5 % are deployed as effectors. Over one-third of all effector genes are clustered in 21 putative 'effector islands' in the genome. We identify a dorsal gland promoter element motif (termed DOG Box) present upstream in representatives from 26 out of 28 dorsal gland effector families, and predict a putative effector superset associated with this motif. We validate gland cell expression in two novel genes by in situ hybridisation and catalogue dorsal gland promoter element-containing effectors from available cyst nematode genomes. Comparison of effector diversity between pathotypes highlights correlation with plant resistance-breaking. These G. rostochiensis genome resources will facilitate major advances in understanding nematode plant-parasitism. Dorsal gland promoter element-containing effectors are at the front line of the evolutionary arms race between plant and parasite and the ability to predict gland cell expression a priori promises rapid advances in understanding their roles and mechanisms of action.

  2. The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes.

    Science.gov (United States)

    Zheng, Jinshui; Peng, Donghai; Chen, Ling; Liu, Hualin; Chen, Feng; Xu, Mengci; Ju, Shouyong; Ruan, Lifang; Sun, Ming

    2016-07-27

    Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans, the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants. © 2016 The Author(s).

  3. Mutations inside rifampicin-resistance determining region of rpoB gene associated with rifampicin-resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Zaw, Myo T; Emran, Nor A; Lin, Zaw

    2018-04-26

    Rifampicin (RIF) plays a pivotal role in the treatment of tuberculosis due to its bactericidal effects. Because the action of RIF is on rpoB gene encoding RNA polymerase β subunit, 95% of RIF resistant mutations are present in rpoB gene. The majority of the mutations in rpoB gene are found within an 81bp RIF-resistance determining region (RRDR). Literatures on RIF resistant mutations published between 2010 and 2016 were thoroughly reviewed. The most commonly mutated codons in RRDR of rpoB gene are 531, 526 and 516. The possibilities of absence of mutation in RRDR of rpoB gene in MDR-TB isolates in few studies was due to existence of other rare rpoB mutations outside RRDR or different mechanism of rifampicin resistance. Molecular methods which can identify extensive mutations associated with multiple anti-tuberculous drugs are in urgent need so that the research on drug resistant mutations should be extended. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. [Mechanisms of endogenous drug resistance acquisition by spontaneous chromosomal gene mutation].

    Science.gov (United States)

    Fukuda, H; Hiramatsu, K

    1997-05-01

    Endogenous resistance in bacteria is caused by a change or loss of function and generally genetically recessive. However, this type of resistance acquisition are now prevalent in clinical setting. Chromosomal genes that afford endogenous resistance are the genes correlated with the target of the drug, the drug inactivating enzymes, and permeability of the molecules including the antibacterial agents. Endogenous alteration of the drug target are mediated by the spontaneous mutation of their structural gene. This mutation provides much lower affinity of the drugs for the target. Gene expression of the inactivating enzymes, such as class C beta-lactamase, is generally regulated by regulatory genes. Spontaneous mutations in the regulatory genes cause constitutive enzyme production and provides the resistant to the agent which is usually stable for such enzymes. Spontaneous mutation in the structural gene gives the enzyme extra-spectrum substrate specificity, like ESBL (Extra-Spectrum-beta-Lactamase). Expression of structural genes encoding the permeability systems are also regulated by some regulatory genes. The spontaneous mutation of the regulatory genes reduce an amount of porin protein. This mutation causes much lower influx of the drug in the cell. Spontaneous mutation in promoter region of the structural gene of efflux protein was observed. This mutation raised the gene transcription and overproduced efflux protein. This protein progresses the drug efflux from the cell.

  5. Gene Expression Profiling of Cecropin B-Resistant Haemophilus parasuis

    NARCIS (Netherlands)

    Wang, Chunmei; Chen, Fangzhou; Hu, H