Science.gov

Sample records for leaf roll virus

  1. Characterization of R genes involved in resistance to Cherry leaf roll virus in paradox hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A single dominant ‘R’ gene (clrvR), in black walnuts (Juglans hindsii) or ‘paradox’ hybrids (J. hindsii x J. regia) confers resistance to Cherry leaf roll virus (CLRV), the causal agent of blackline disease. The identification and cloning of the ‘R’ gene is expected to aid the walnut breeding progra...

  2. 40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Potato Leaf Roll Virus Resistance Gene... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.513 Potato Leaf Roll... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all...

  3. 40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Potato Leaf Roll Virus Resistance Gene... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.513 Potato Leaf Roll... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all...

  4. 40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Potato Leaf Roll Virus Resistance Gene... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.513 Potato Leaf Roll... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all...

  5. 40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Potato Leaf Roll Virus Resistance Gene... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.513 Potato Leaf Roll... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all...

  6. 40 CFR 174.513 - Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene); exemption from the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Potato Leaf Roll Virus Resistance Gene... REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.513 Potato Leaf Roll... protectant Potato Leaf Roll Virus Resistance Gene (also known as orf1/orf2 gene) in or on all...

  7. Resistance to potato leaf roll virus multiplication in potato is under major gene control.

    PubMed

    Barker, H; Solomon-Blackburn, R M; McNicol, J W; Bradshaw, J E

    1994-08-01

    The concentration of potato leaf roll virus (PLRV), as measured by a quantitative enzyme-linked immunosorbent assay, in the foliage of potato plants (Solanum tuberosum) of cv 'Maris Piper' with secondary infection was 2900 ng/g leaf, whereas in clones G7445(1) and G7032(5) it was 180 ng/g leaf and 120 ng/g leaf, respectively. To examine the genetic control of resistance to PLRV multiplication, reciprocal crosses were made between the susceptible cultivar 'Maris Piper' and the two resistant clones, and the three parents were selfed. Seedling progenies of these families were grown to generate tubers of individual genotypes (clones). Clonally propagated plants were graft-inoculated, and their daughter tubers were collected and used to grow plants with secondary infection in which PLRV concentration was estimated. The expression of resistance to PLRV multiplication had a bimodal distribution in progenies from crosses between 'Maris Piper' and either resistant clone, and also in progeny from selfing the resistant parents, with genotypes segregating into high and low virus titre groups. Only the progeny obtained from selfing 'Maris Piper' did not segregate, all genotypes being susceptible to PLRV multiplication. The pattern of segregation obtained from these progenies fits more closely with the genetical hypothesis that resistance to PLRV multiplication is controlled by two unlinked dominant complementary genes, both of which are required for resistance, than with the simpler hypothesis that resistance is conferred by a single dominant gene, as published previously.

  8. Comparison of diagnostic techniques for the detection and differentiation of Cherry leaf roll virus strains for quarantine purposes.

    PubMed

    Lebas, B S M; Veerakone, S; Liefting, L W; Tang, J; Perez-Egusquiza, Z; von Bargen, S; Ward, L

    2016-08-01

    Some strains of Cherry leaf roll virus (CLRV) are considered as quarantine pests in New Zealand. CLRV was detected in seven plant host species: Actinidia chinensis, Hydrangea macrophylla, Malus domestica, Plantago major, Ribes rubrum, Rubus idaeus and Rumex sp. collected from New Zealand between 2005 and 2012. Biological, serological and molecular techniques were compared for the detection and differentiation of CLRV isolates. The biological analysis revealed differences in symptomatology and disease severity among the isolates. The five isolates tested by ELISA were serologically related to each other using polyclonal antisera with only one out of four commercially-available antisera successfully detecting all of them. The phylogenetic analysis of sequences obtained from parts of the coat protein, polymerase and 3'-untranslated regions revealed that the New Zealand CLRV isolates clustered into two closely related but distinct phylogenetic groups with some isolates grouping differently depending on the gene studied. The New Zealand CLRV isolates were clearly distinct to overseas isolates found in phylogenetic groups A, D and E. The conventional RT-PCR using primers targeting the CLRV coat protein coding region is recommended for determining sequence differences between strains. These findings will be useful in making regulatory decisions with regard to the testing requirements and the CLRV strains to be regulated in New Zealand. PMID:27129669

  9. Cherry leaf roll virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the blackberry cultivar Himalaya Giant naturally infected in England, CLRV is reported to cause chlorotic mottling and line patterning in leaves. Infected plants are stunted and may be killed. In three red raspberry cultivars naturally infected by CLRV in New Zealand, infected plants had stunted,...

  10. Semi-Rolled Leaf2 modulates rice leaf rolling by regulating abaxial side cell differentiation.

    PubMed

    Liu, Xiaofei; Li, Ming; Liu, Kai; Tang, Ding; Sun, Mingfa; Li, Yafei; Shen, Yi; Du, Guijie; Cheng, Zhukuan

    2016-04-01

    Moderate leaf rolling maintains the erectness of leaves and minimizes the shadowing between leaves which is helpful to establish ideal plant architecture. Here, we describe asrl2(semi-rolled leaf2) rice mutant, which has incurved leaves due to the presence of defective sclerenchymatous cells on the abaxial side of the leaf and displays narrow leaves and reduced plant height. Map-based cloning revealed that SRL2 encodes a novel plant-specific protein of unknown biochemical function.SRL2 was mainly expressed in the vascular bundles of leaf blades, leaf sheaths, and roots, especially in their sclerenchymatous cells. The transcriptional activities of several leaf development-related YABBY genes were significantly altered in the srl2 mutant. Double mutant analysis suggested that SRL2 and SHALLOT-LIKE1(SLL1)/ROLLED LEAF9(RL9) function in distinct pathways that regulate abaxial-side leaf development. Hence, SRL2 plays an important role in regulating leaf development, particularly during sclerenchymatous cell differentiation.

  11. Semi-Rolled Leaf2 modulates rice leaf rolling by regulating abaxial side cell differentiation

    PubMed Central

    Liu, Xiaofei; Li, Ming; Liu, Kai; Tang, Ding; Sun, Mingfa; Li, Yafei; Shen, Yi; Du, Guijie; Cheng, Zhukuan

    2016-01-01

    Moderate leaf rolling maintains the erectness of leaves and minimizes the shadowing between leaves which is helpful to establish ideal plant architecture. Here, we describe a srl2 (semi-rolled leaf2) rice mutant, which has incurved leaves due to the presence of defective sclerenchymatous cells on the abaxial side of the leaf and displays narrow leaves and reduced plant height. Map-based cloning revealed that SRL2 encodes a novel plant-specific protein of unknown biochemical function. SRL2 was mainly expressed in the vascular bundles of leaf blades, leaf sheaths, and roots, especially in their sclerenchymatous cells. The transcriptional activities of several leaf development-related YABBY genes were significantly altered in the srl2 mutant. Double mutant analysis suggested that SRL2 and SHALLOT-LIKE1 (SLL1)/ROLLED LEAF9 (RL9) function in distinct pathways that regulate abaxial-side leaf development. Hence, SRL2 plays an important role in regulating leaf development, particularly during sclerenchymatous cell differentiation. PMID:26873975

  12. Semi-Rolled Leaf2 modulates rice leaf rolling by regulating abaxial side cell differentiation.

    PubMed

    Liu, Xiaofei; Li, Ming; Liu, Kai; Tang, Ding; Sun, Mingfa; Li, Yafei; Shen, Yi; Du, Guijie; Cheng, Zhukuan

    2016-04-01

    Moderate leaf rolling maintains the erectness of leaves and minimizes the shadowing between leaves which is helpful to establish ideal plant architecture. Here, we describe asrl2(semi-rolled leaf2) rice mutant, which has incurved leaves due to the presence of defective sclerenchymatous cells on the abaxial side of the leaf and displays narrow leaves and reduced plant height. Map-based cloning revealed that SRL2 encodes a novel plant-specific protein of unknown biochemical function.SRL2 was mainly expressed in the vascular bundles of leaf blades, leaf sheaths, and roots, especially in their sclerenchymatous cells. The transcriptional activities of several leaf development-related YABBY genes were significantly altered in the srl2 mutant. Double mutant analysis suggested that SRL2 and SHALLOT-LIKE1(SLL1)/ROLLED LEAF9(RL9) function in distinct pathways that regulate abaxial-side leaf development. Hence, SRL2 plays an important role in regulating leaf development, particularly during sclerenchymatous cell differentiation. PMID:26873975

  13. First report of seed-borne cherry leaf roll virus in wild potato, Solanum acaule, from South America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A virus, designated JCM-79, was isolated from wild potato (Solanum acaule Bitt.) plants grown from true seed received at USDA-APHIS Potato Quarantine Program from Peru. JCM-79 was mechanically transmissible to Nicotiana clevelandii, N.tabacum cv. Samsun NN, and Chenopodium quinoa. Symptoms in the ...

  14. Development of molecular resistance in potato against potato leaf roll virus and potato virus Y through Agrobacterium-mediated double transgenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato leafroll virus (PLRV) and potato virus Y (PVY) are the two major viral problems for the potato production all over the world. Transgenic approaches involving the expression of viral genes are being developed to provide protection for plants against viral diseases. The purpose of this study w...

  15. SHALLOT-LIKE1 is a KANADI transcription factor that modulates rice leaf rolling by regulating leaf abaxial cell development.

    PubMed

    Zhang, Guang-Heng; Xu, Qian; Zhu, Xu-Dong; Qian, Qian; Xue, Hong-Wei

    2009-03-01

    As an important agronomic trait, rice (Oryza sativa L.) leaf rolling has attracted much attention from plant biologists and breeders. Moderate leaf rolling increases the photosynthesis of cultivars and hence raises grain yield. However, the relevant molecular mechanism remains unclear. Here, we show the isolation and functional characterization of SHALLOT-LIKE1 (SLL1), a key gene controlling rice leaf rolling. sll1 mutant plants have extremely incurved leaves due to the defective development of sclerenchymatous cells on the abaxial side. Defective development can be functionally rescued by expression of SLL1. SLL1 is transcribed in various tissues and accumulates in the abaxial epidermis throughout leaf development. SLL1 encodes a SHAQKYF class MYB family transcription factor belonging to the KANADI family. SLL1 deficiency leads to defective programmed cell death of abaxial mesophyll cells and suppresses the development of abaxial features. By contrast, enhanced SLL1 expression stimulates phloem development on the abaxial side and suppresses bulliform cell and sclerenchyma development on the adaxial side. Additionally, SLL1 deficiency results in increased chlorophyll and photosynthesis. Our findings identify the role of SLL1 in the modulation of leaf abaxial cell development and in sustaining abaxial characteristics during leaf development. These results should facilitate attempts to use molecular breeding to increase the photosynthetic capacity of rice, as well as other crops, by modulating leaf development and rolling.

  16. SHALLOT-LIKE1 is a KANADI transcription factor that modulates rice leaf rolling by regulating leaf abaxial cell development.

    PubMed

    Zhang, Guang-Heng; Xu, Qian; Zhu, Xu-Dong; Qian, Qian; Xue, Hong-Wei

    2009-03-01

    As an important agronomic trait, rice (Oryza sativa L.) leaf rolling has attracted much attention from plant biologists and breeders. Moderate leaf rolling increases the photosynthesis of cultivars and hence raises grain yield. However, the relevant molecular mechanism remains unclear. Here, we show the isolation and functional characterization of SHALLOT-LIKE1 (SLL1), a key gene controlling rice leaf rolling. sll1 mutant plants have extremely incurved leaves due to the defective development of sclerenchymatous cells on the abaxial side. Defective development can be functionally rescued by expression of SLL1. SLL1 is transcribed in various tissues and accumulates in the abaxial epidermis throughout leaf development. SLL1 encodes a SHAQKYF class MYB family transcription factor belonging to the KANADI family. SLL1 deficiency leads to defective programmed cell death of abaxial mesophyll cells and suppresses the development of abaxial features. By contrast, enhanced SLL1 expression stimulates phloem development on the abaxial side and suppresses bulliform cell and sclerenchyma development on the adaxial side. Additionally, SLL1 deficiency results in increased chlorophyll and photosynthesis. Our findings identify the role of SLL1 in the modulation of leaf abaxial cell development and in sustaining abaxial characteristics during leaf development. These results should facilitate attempts to use molecular breeding to increase the photosynthetic capacity of rice, as well as other crops, by modulating leaf development and rolling. PMID:19304938

  17. Characterization of Rolled and Erect Leaf 1 in regulating leave morphology in rice

    PubMed Central

    Chen, Qiaoling; Xie, Qingjun; Gao, Ju; Wang, Wenyi; Sun, Bo; Liu, Bohan; Zhu, Haitao; Peng, Haifeng; Zhao, Haibing; Liu, Changhong; Wang, Jiang; Zhang, Jingliu; Zhang, Guiquan; Zhang, Zemin

    2015-01-01

    Leaf morphology, particularly in crop, is one of the most important agronomic traits because it influences the yield through the manipulation of photosynthetic capacity and transpiration. To understand the regulatory mechanism of leaf morphogenesis, an Oryza sativa dominant mutant, rolled and erect leaf 1 (rel1) has been characterized. This mutant has a predominant rolled leaf, increased leaf angle, and reduced plant height phenotype that results in a reduction in grain yield. Electron microscope observations indicated that the leaf incurvations of rel1 dominant mutants result from the alteration of the size and number of bulliform cells. Molecular cloning revealed that the rel1 dominant mutant phenotype is caused by the activation of the REL1 gene, which encodes a novel unknown protein, despite its high degree of conservation among monocot plants. Moreover, the downregulation of the REL1 gene in the rel1 dominant mutant restored the phenotype of this dominant mutant. Alternatively, overexpression of REL1 in wild-type plants induced a phenotype similar to that of the dominant rel1 mutant, indicating that REL1 plays a positive role in leaf rolling and bending. Consistent with the observed rel1 phenotype, the REL1 gene was predominantly expressed in the meristem of various tissues during plant growth and development. Nevertheless, the responsiveness of both rel1 dominant mutants and REL1-overexpressing plants to exogenous brassinosteroid (BR) was reduced. Moreover, transcript levels of BR response genes in the rel1 dominant mutants and REL1-overexpressing lines were significantly altered. Additionally, seven REL1-interacting proteins were also identified from a yeast two-hybrid screen. Taken together, these findings suggest that REL1 regulates leaf morphology, particularly in leaf rolling and bending, through the coordination of BR signalling transduction. PMID:26142419

  18. Characterization of Rolled and Erect Leaf 1 in regulating leave morphology in rice.

    PubMed

    Chen, Qiaoling; Xie, Qingjun; Gao, Ju; Wang, Wenyi; Sun, Bo; Liu, Bohan; Zhu, Haitao; Peng, Haifeng; Zhao, Haibing; Liu, Changhong; Wang, Jiang; Zhang, Jingliu; Zhang, Guiquan; Zhang, Zemin

    2015-09-01

    Leaf morphology, particularly in crop, is one of the most important agronomic traits because it influences the yield through the manipulation of photosynthetic capacity and transpiration. To understand the regulatory mechanism of leaf morphogenesis, an Oryza sativa dominant mutant, rolled and erect leaf 1 (rel1) has been characterized. This mutant has a predominant rolled leaf, increased leaf angle, and reduced plant height phenotype that results in a reduction in grain yield. Electron microscope observations indicated that the leaf incurvations of rel1 dominant mutants result from the alteration of the size and number of bulliform cells. Molecular cloning revealed that the rel1 dominant mutant phenotype is caused by the activation of the REL1 gene, which encodes a novel unknown protein, despite its high degree of conservation among monocot plants. Moreover, the downregulation of the REL1 gene in the rel1 dominant mutant restored the phenotype of this dominant mutant. Alternatively, overexpression of REL1 in wild-type plants induced a phenotype similar to that of the dominant rel1 mutant, indicating that REL1 plays a positive role in leaf rolling and bending. Consistent with the observed rel1 phenotype, the REL1 gene was predominantly expressed in the meristem of various tissues during plant growth and development. Nevertheless, the responsiveness of both rel1 dominant mutants and REL1-overexpressing plants to exogenous brassinosteroid (BR) was reduced. Moreover, transcript levels of BR response genes in the rel1 dominant mutants and REL1-overexpressing lines were significantly altered. Additionally, seven REL1-interacting proteins were also identified from a yeast two-hybrid screen. Taken together, these findings suggest that REL1 regulates leaf morphology, particularly in leaf rolling and bending, through the coordination of BR signalling transduction.

  19. Photosystem II functionality and antioxidant system changes during leaf rolling in post-stress emerging Ctenanthe setosa exposed to drought.

    PubMed

    Terzi, Rabiye; Saruhan, Neslihan; Sağlam, A; Nar, Hatice; Kadioğlu, A

    2009-12-01

    We studied the changes in antioxidant system and chlorophyll fluorescence parameters in post-stress emerging Ctenanthe setosa (Rosc.) Eichler (Marantaceae) plants (PSE plants) having reduced leaf area under drought stress causing leaf rolling and re-watering. PSE plants were compared to primary stressed plants (PS) in previous studies. The parameters were measured at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others is intermediate form). Water potentials and stomatal conductance of leaves were gradually decreased during leaf rolling. Similarly, maximum quantum efficiency of open PS II center and quantum yield of PS II decreased during the rolling period. Non-photochemical quenching of chlorophyll fluorescence decreased at score 2 then increased while photochemical quenching did not change during leaf rolling. Electron transport rate decreased only at score 4 but approximately reached to score 1 level after re-watering. Superoxide dismutase activity was not constant at all leaf rolling scores. Ascorbate peroxidase, catalase and glutathione reductase activities generally tended to increase during leaf rolling. Lipid peroxidation and H 2 O 2 content increased at score 2 but decreased at the later scores. On the other hand, O 2 .- production increased during the rolling period. After re-watering of the plants having score 4 of leaf rolling, antioxidant enzyme activities were lower than those of score 1. Other physiological parameters also tended to reach the value of score 1. The results indicated that PSE plants gained drought tolerance by reducing leaf area effectively induced their antioxidant systems and protected the photosynthesis under drought stress similar to PS plants. PMID:20015833

  20. Photosystem II functionality and antioxidant system changes during leaf rolling in post-stress emerging Ctenanthe setosa exposed to drought.

    PubMed

    Terzi, Rabiye; Saruhan, Neslihan; Sağlam, A; Nar, Hatice; Kadioğlu, A

    2009-12-01

    We studied the changes in antioxidant system and chlorophyll fluorescence parameters in post-stress emerging Ctenanthe setosa (Rosc.) Eichler (Marantaceae) plants (PSE plants) having reduced leaf area under drought stress causing leaf rolling and re-watering. PSE plants were compared to primary stressed plants (PS) in previous studies. The parameters were measured at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others is intermediate form). Water potentials and stomatal conductance of leaves were gradually decreased during leaf rolling. Similarly, maximum quantum efficiency of open PS II center and quantum yield of PS II decreased during the rolling period. Non-photochemical quenching of chlorophyll fluorescence decreased at score 2 then increased while photochemical quenching did not change during leaf rolling. Electron transport rate decreased only at score 4 but approximately reached to score 1 level after re-watering. Superoxide dismutase activity was not constant at all leaf rolling scores. Ascorbate peroxidase, catalase and glutathione reductase activities generally tended to increase during leaf rolling. Lipid peroxidation and H 2 O 2 content increased at score 2 but decreased at the later scores. On the other hand, O 2 .- production increased during the rolling period. After re-watering of the plants having score 4 of leaf rolling, antioxidant enzyme activities were lower than those of score 1. Other physiological parameters also tended to reach the value of score 1. The results indicated that PSE plants gained drought tolerance by reducing leaf area effectively induced their antioxidant systems and protected the photosynthesis under drought stress similar to PS plants.

  1. Notes on the ecology of rolled-leaf hispines (Chrysomelidae, Cassidinae) at La Gamba (Costa Rica).

    PubMed

    Schmitt, Michael; Frank, Meike

    2013-01-01

    A total of 301 adult hispine beetles of the genera Cephaloleia and Chelobasis were found in rolled leaves of plants of 17 species of Zingiberales (families Costaceae, Heliconiaceae, Maranthaceae, Musaceae, and Zingiberaceae) during a field study at La Gamba, Golfito region, Costa Rica. Of these beetles, Cephaloleia belti was recorded from 12 potential host plant species, C. distincta from 7, C. dilaticollis from 5, C., Chelobasis bicolor, C. championi, and C. histrionica from 3, Chelobasis perplexa and C. instabilis from 2, whereas C. trivittata from only one. Of the plant species, Heliconia latispatha had 7 beetle species in its leaf rolls, Calathea lutea had 5, H. imbricata and H. rostrata had 4, H. stricta and Musa paradisiaca had 3, H. wagneriana had 2, while on H. vaginalis, H. danielsiana, H. densiflora, H. longiflora, Calathea crotalifera, C. platystachya, Goeppertia lasiophylla, Alpinia purpurata, Costus pulverulentus and Costus barbatus, H. densiflora, H. vaginalis, and H. danielsana only hispines of one species were found. Cephaloleia belti occurred together with beetles of six other hispine species, whereas Cephaloleia trivittata never shared a leaf roll with another hispine species. The remaining beetle species aggregated with one to four other hispines. Adults of C. belti and C. championi were frequently seen, occasionally also with C. dilaticollis, C. histrionica, and Chelobasis perplexa, to co-occur with the carabid Calophaena ligata in the same leaf roll without any sign of interspecific aggression. A comparison of host choices and the phylogeny of the hispines and of their host plants revealed no signs that beetles used species level phylogenetic relationships within the Zingiberales to select food plants. Obviously, within this plant order, rolled-leaf hispines choose their plant hosts in a nearly opportunistic manner. Seemingly, they use differences among plants at higher taxonomic levels but within the Zingiberales, the availability of young

  2. Association of tomato leaf curl Sudan virus with leaf curl disease of tomato in Jeddah, Saudi Arabia.

    PubMed

    Sohrab, Sayed Sartaj; Yasir, Muhammad; El-Kafrawy, Sherif Ali; Abbas, Ayman T; Mousa, Magdi Ali Ahmed; Bakhashwain, Ahmed A

    2016-06-01

    Tomato is an important vegetable crop and its production is adversely affected by leaf curl disease caused by begomovirus. Leaf curl disease is a serious concern for tomato crops caused by begomovirus in Jeddah, Kingdom of Saudi Arabia. Tomato leaf curl disease has been shown to be mainly caused either by tomato leaf curl Sudan virus or tomato yellow leaf curl virus as well as tomato leaf curl Oman virus. Many tomato plants infected with monopartite begomoviruses were also found to harbor a symptom enhancing betasatellites. Here we report the association of tomato leaf curl Sudan virus causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia. The complete genome sequence analysis showed highest (99.9 %) identity with tomato leaf curl Sudan virus causing leaf curl disease in Arabian Peninsula. In phylogenetic relationships analysis, the identified virus formed closest cluster with tomato leaf curl Sudan virus. In recombination analysis study, the major parent was identified as tomato leaf curl Sudan virus. Findings of this study strongly supports the associated virus is a variant of tomato leaf curl Sudan virus causing disease in Sudan, Yemen and Arabian Peninsula. The betasatellites sequence analysis showed highest identity (99.8 %) with tomato leaf curl betasatellites-Amaranthus-Jeddah. The phylogenetic analysis result based on betasatellites formed closed cluster with tomato yellow leaf curl Oman betasatellites. The importance of these findings and occurrence of begomovirus in new geographic regions causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia are discussed.

  3. Association of tomato leaf curl Sudan virus with leaf curl disease of tomato in Jeddah, Saudi Arabia.

    PubMed

    Sohrab, Sayed Sartaj; Yasir, Muhammad; El-Kafrawy, Sherif Ali; Abbas, Ayman T; Mousa, Magdi Ali Ahmed; Bakhashwain, Ahmed A

    2016-06-01

    Tomato is an important vegetable crop and its production is adversely affected by leaf curl disease caused by begomovirus. Leaf curl disease is a serious concern for tomato crops caused by begomovirus in Jeddah, Kingdom of Saudi Arabia. Tomato leaf curl disease has been shown to be mainly caused either by tomato leaf curl Sudan virus or tomato yellow leaf curl virus as well as tomato leaf curl Oman virus. Many tomato plants infected with monopartite begomoviruses were also found to harbor a symptom enhancing betasatellites. Here we report the association of tomato leaf curl Sudan virus causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia. The complete genome sequence analysis showed highest (99.9 %) identity with tomato leaf curl Sudan virus causing leaf curl disease in Arabian Peninsula. In phylogenetic relationships analysis, the identified virus formed closest cluster with tomato leaf curl Sudan virus. In recombination analysis study, the major parent was identified as tomato leaf curl Sudan virus. Findings of this study strongly supports the associated virus is a variant of tomato leaf curl Sudan virus causing disease in Sudan, Yemen and Arabian Peninsula. The betasatellites sequence analysis showed highest identity (99.8 %) with tomato leaf curl betasatellites-Amaranthus-Jeddah. The phylogenetic analysis result based on betasatellites formed closed cluster with tomato yellow leaf curl Oman betasatellites. The importance of these findings and occurrence of begomovirus in new geographic regions causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia are discussed. PMID:27366765

  4. SHALLOT-LIKE1 Is a KANADI Transcription Factor That Modulates Rice Leaf Rolling by Regulating Leaf Abaxial Cell Development[W][OA

    PubMed Central

    Zhang, Guang-Heng; Xu, Qian; Zhu, Xu-Dong; Qian, Qian; Xue, Hong-Wei

    2009-01-01

    As an important agronomic trait, rice (Oryza sativa L.) leaf rolling has attracted much attention from plant biologists and breeders. Moderate leaf rolling increases the photosynthesis of cultivars and hence raises grain yield. However, the relevant molecular mechanism remains unclear. Here, we show the isolation and functional characterization of SHALLOT-LIKE1 (SLL1), a key gene controlling rice leaf rolling. sll1 mutant plants have extremely incurved leaves due to the defective development of sclerenchymatous cells on the abaxial side. Defective development can be functionally rescued by expression of SLL1. SLL1 is transcribed in various tissues and accumulates in the abaxial epidermis throughout leaf development. SLL1 encodes a SHAQKYF class MYB family transcription factor belonging to the KANADI family. SLL1 deficiency leads to defective programmed cell death of abaxial mesophyll cells and suppresses the development of abaxial features. By contrast, enhanced SLL1 expression stimulates phloem development on the abaxial side and suppresses bulliform cell and sclerenchyma development on the adaxial side. Additionally, SLL1 deficiency results in increased chlorophyll and photosynthesis. Our findings identify the role of SLL1 in the modulation of leaf abaxial cell development and in sustaining abaxial characteristics during leaf development. These results should facilitate attempts to use molecular breeding to increase the photosynthetic capacity of rice, as well as other crops, by modulating leaf development and rolling. PMID:19304938

  5. Mining cotton germplasm resources to fight Cotton Leaf Curl Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CLCuV (Cotton Leaf Curl Virus) is a major threat to cotton production in Pakistan and parts of India and has been reported in cotton producing countries in Africa, as well as China and Uzbekistan. Identifying sources of resistance to CLCuV helps not only countries such as Pakistan where the virus is...

  6. The complete nucleotide sequence of pelargonium leaf curl virus.

    PubMed

    McGavin, Wendy J; MacFarlane, Stuart A

    2016-05-01

    Investigation of a tombusvirus isolated from tulip plants in Scotland revealed that it was pelargonium leaf curl virus (PLCV) rather than the originally suggested tomato bushy stunt virus. The complete sequence of the PLCV genome was determined for the first time, revealing it to be 4789 nucleotides in size and to have an organization similar to that of the other, previously described tombusviruses. Primers derived from the sequence were used to construct a full-length infectious clone of PLCV that recapitulates the disease symptoms of leaf curling in systemically infected pelargonium plants.

  7. The complete nucleotide sequence of pelargonium leaf curl virus.

    PubMed

    McGavin, Wendy J; MacFarlane, Stuart A

    2016-05-01

    Investigation of a tombusvirus isolated from tulip plants in Scotland revealed that it was pelargonium leaf curl virus (PLCV) rather than the originally suggested tomato bushy stunt virus. The complete sequence of the PLCV genome was determined for the first time, revealing it to be 4789 nucleotides in size and to have an organization similar to that of the other, previously described tombusviruses. Primers derived from the sequence were used to construct a full-length infectious clone of PLCV that recapitulates the disease symptoms of leaf curling in systemically infected pelargonium plants. PMID:26906694

  8. Carrot yellow leaf virus Is Associated with Carrot Internal Necrosis

    PubMed Central

    Adams, Ian P.; Skelton, Anna; Macarthur, Roy; Hodges, Tobias; Hinds, Howard; Flint, Laura; Nath, Palash Deb; Boonham, Neil; Fox, Adrian

    2014-01-01

    Internal necrosis of carrot has been observed in UK carrots for at least 10 years, and has been anecdotally linked to virus infection. In the 2009 growing season some growers had up to 10% of yield with these symptoms. Traditional diagnostic methods are targeted towards specific pathogens. By using a metagenomic approach with high throughput sequencing technology, other, as yet unidentified causes of root necrosis were investigated. Additionally a statistical analysis has shown which viruses are most closely associated with disease symptoms. Carrot samples were collected from a crop exhibiting root necrosis (102 Affected: 99 Unaffected) and tested for the presence of the established carrot viruses: Carrot red leaf virus (CtRLV), Carrot mottle virus (CMoV), Carrot red leaf associated viral RNA (CtRLVaRNA) and Parsnip yellow fleck virus (PYFV). The presence of these viruses was not associated with symptomatic carrot roots either as single viruses or in combinations. A sub-sample of carrots of mixed symptom status was subjected to MiSeq sequencing. The results from these tests suggested Carrot yellow leaf virus (CYLV) was associated with symptomatic roots. Additionally a novel Torradovirus, a novel Closterovirus and two novel Betaflexiviradae related plant viruses were detected. A specific diagnostic test was designed for CYLV. Of the 102 affected carrots, 98% were positive for CYLV compared to 22% of the unaffected carrots. From these data we conclude that although we have yet to practically demonstrate a causal link, CYLV appears to be strongly associated with the presence of necrosis of carrots. PMID:25365290

  9. DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus.

    PubMed

    Jeske, H; Lütgemeier, M; Preiss, W

    2001-11-01

    Geminiviruses have spread worldwide and have become increasingly important in crop plants during recent decades. Recombination among geminiviruses was one major source of new variants. Geminiviruses replicate via rolling circles, confirmed here by electron microscopic visualization and two-dimensional gel analysis of Abutilon mosaic virus (AbMV) DNA. However, only a minority of DNA intermediates are consistent with this model. The majority are compatible with recombination-dependent replication (RDR). During development of naturally infected leaves, viral intermediates compatible with both models appeared simultaneously, whereas agro-infection of leaf discs with AbMV led to an early appearance of RDR forms but no RCR intermediates. Inactivation of viral genes ac2 and ac3 delayed replication, but produced the same DNA types as after wild-type infection, indicating that these genes were not essential for RDR in leaf discs. In conclusion, host factors alone or in combination with the viral AC1 protein are necessary and sufficient for the production of RDR intermediates. The consequences of an inherent geminiviral recombination activity for the use of pathogen-derived resistance traits are discussed.

  10. DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus

    PubMed Central

    Jeske, Holger; Lütgemeier, Martin; Preiß, Werner

    2001-01-01

    Geminiviruses have spread worldwide and have become increasingly important in crop plants during recent decades. Recombination among geminiviruses was one major source of new variants. Geminiviruses replicate via rolling circles, confirmed here by electron microscopic visualization and two-dimensional gel analysis of Abutilon mosaic virus (AbMV) DNA. However, only a minority of DNA intermediates are consistent with this model. The majority are compatible with recombination-dependent replication (RDR). During development of naturally infected leaves, viral intermediates compatible with both models appeared simultaneously, whereas agro-infection of leaf discs with AbMV led to an early appearance of RDR forms but no RCR intermediates. Inactivation of viral genes ac2 and ac3 delayed replication, but produced the same DNA types as after wild-type infection, indicating that these genes were not essential for RDR in leaf discs. In conclusion, host factors alone or in combination with the viral AC1 protein are necessary and sufficient for the production of RDR intermediates. The consequences of an inherent geminiviral recombination activity for the use of pathogen-derived resistance traits are discussed. PMID:11689455

  11. Joint Mapping and Allele Mining of the Rolled Leaf Trait in Rice (Oryza sativa L.)

    PubMed Central

    Wang, Chunchao; Nafisah; Joseph, Charles; Zhang, Wenzhong; Xu, Jianlong; Li, Zhikang

    2016-01-01

    The rolled leaf trait, long considered to be a key component of plant architecture, represents an important target trait for improving plant architecture at the population level. We therefore performed linkage mapping using a set of 262 highly variable RILs from two rice cultivars (Minghui 63 and 02428) with minor differences in leaf rolling index (LRI) in conjunction with GWAS mapping of a random subset of the 1127 germplasms from the 3K Rice Genomes Project (3K Rice). A total of seven main-effect loci were found to underlie the transgressive segregation of progenies from parents with minor differences in LRI. Five of these loci were previously identified and two (qRl7b and qRl9b) are newly reported with additional evidence from GWAS mapping for qRl7b. A total of 18 QTLs were identified by GWAS, including four newly identified QTLs. Six QTLs were confirmed by linkage mapping with the above RIL population, and 83.3% were found to be consistent with previously reported loci based on comparative mapping. We also performed allele mining with representative SNPs and identified the elite germplasms for the improvement of rolled leaf trait. Most favorable alleles at the detected loci were contributed by various 3K Rice germplasms. By a re-scanning of the candidate region with more saturated SNP markers, we dissected the region harboring gRl4-2 into three subregions, in which the average effect on LRI was 3.5% with a range from 2.4 to 4.1% in the third subregion, suggesting the presence of a new locus or loci within this region. The representative SNPs for favorable alleles in the reliable QTLs which were consistently identified in both bi-parental mapping and GWAS, such as qRl4, qRl5, qRl6, qRl7a, and qRl7b will be useful for future molecular breeding programs for ideal plant type in rice. PMID:27441398

  12. Joint Mapping and Allele Mining of the Rolled Leaf Trait in Rice (Oryza sativa L.).

    PubMed

    Zhang, Qiang; Zheng, Tianqing; Hoang, Long; Wang, Chunchao; Nafisah; Joseph, Charles; Zhang, Wenzhong; Xu, Jianlong; Li, Zhikang

    2016-01-01

    The rolled leaf trait, long considered to be a key component of plant architecture, represents an important target trait for improving plant architecture at the population level. We therefore performed linkage mapping using a set of 262 highly variable RILs from two rice cultivars (Minghui 63 and 02428) with minor differences in leaf rolling index (LRI) in conjunction with GWAS mapping of a random subset of the 1127 germplasms from the 3K Rice Genomes Project (3K Rice). A total of seven main-effect loci were found to underlie the transgressive segregation of progenies from parents with minor differences in LRI. Five of these loci were previously identified and two (qRl7b and qRl9b) are newly reported with additional evidence from GWAS mapping for qRl7b. A total of 18 QTLs were identified by GWAS, including four newly identified QTLs. Six QTLs were confirmed by linkage mapping with the above RIL population, and 83.3% were found to be consistent with previously reported loci based on comparative mapping. We also performed allele mining with representative SNPs and identified the elite germplasms for the improvement of rolled leaf trait. Most favorable alleles at the detected loci were contributed by various 3K Rice germplasms. By a re-scanning of the candidate region with more saturated SNP markers, we dissected the region harboring gRl4-2 into three subregions, in which the average effect on LRI was 3.5% with a range from 2.4 to 4.1% in the third subregion, suggesting the presence of a new locus or loci within this region. The representative SNPs for favorable alleles in the reliable QTLs which were consistently identified in both bi-parental mapping and GWAS, such as qRl4, qRl5, qRl6, qRl7a, and qRl7b will be useful for future molecular breeding programs for ideal plant type in rice. PMID:27441398

  13. Post-transcriptional gene silencing in controlling viruses of the Tomato yellow leaf curl virus complex.

    PubMed

    Abhary, M K; Anfoka, G H; Nakhla, M K; Maxwell, D P

    2006-12-01

    Tomato yellow leaf curl disease (TYLCD) is caused by a group of geminiviruses that belong to the Tomato yellow leaf curl virus (TYLCV) complex and are transmitted by the whitefly (Bemisia tabaci Genn.). The disease causes great yield losses in many countries throughout the Mediterranean region and the Middle East. In this study, the efficacy of post-transcriptional gene silencing (PTGS) to control the disease caused by TYLCV complex was investigated. Non-coding conserved regions from the genome of TYLCV, Tomato yellow leaf curl virus-mild, tomato yellow leaf curl Sardinia virus, tomato yellow leaf curl Malaga virus, and tomato yellow leaf curl Sardinia virus-Spain [2] were selected and used to design a construct that can trigger broad resistance against different viruses that cause tomato yellow leaf curl disease. The silencing construct was cloned into an Agrobacterium-binary vector in sense and antisense orientation and used in transient assay to infiltrate tomato and Nicotiana benthamiana plants. A high level of resistance was obtained when plants were agro-infiltrated with an infectious clone of the Egyptian isolate of TYLCV (TYLCV-[EG]) or challenge inoculated with TYLCV, TYLCV-Mld, and TYLCSV-ES[2] using whitefly-mediated transmission 16-20 days post infiltration with the silencing construct. Results of the polymerase chain reaction showed that the resistance was effective against all three viruses. Furthermore, dot blot hybridization and PCR failed to detect viral DNA in symptomless, silenced plants. A positive correlation between resistance and the accumulation of TYLCV-specific siRNAs was observed in silenced plants. Together, these data provide compelling evidence that PTGS can be used to engineer geminivirus-resistant plants. PMID:16862387

  14. Notes on the ecology of rolled-leaf hispines (Chrysomelidae, Cassidinae) at La Gamba (Costa Rica)1

    PubMed Central

    Schmitt, Michael; Frank, Meike

    2013-01-01

    Abstract A total of 301 adult hispine beetles of the genera Cephaloleia and Chelobasis were found in rolled leaves of plants of 17 species of Zingiberales (families Costaceae, Heliconiaceae, Maranthaceae, Musaceae, and Zingiberaceae) during a field study at La Gamba, Golfito region, Costa Rica. Of these beetles, Cephaloleia belti was recorded from 12 potential host plant species, C. distincta from 7, C. dilaticollis from 5, C., Chelobasis bicolor, C. championi, and C. histrionica from 3, Chelobasis perplexa and C. instabilis from 2, whereas C. trivittata from only one. Of the plant species, Heliconia latispatha had 7 beetle species in its leaf rolls, Calathea lutea had 5, H. imbricata and H. rostrata had 4, H. stricta and Musa paradisiaca had 3, H. wagneriana had 2, while on H. vaginalis, H. danielsiana, H. densiflora, H. longiflora, Calathea crotalifera, C. platystachya, Goeppertia lasiophylla, Alpinia purpurata, Costus pulverulentus and Costus barbatus, H. densiflora, H. vaginalis, and H. danielsana only hispines of one species were found. Cephaloleia belti occurred together with beetles of six other hispine species, whereas Cephaloleia trivittata never shared a leaf roll with another hispine species. The remaining beetle species aggregated with one to four other hispines. Adults of C. belti and C. championi were frequently seen, occasionally also with C. dilaticollis, C. histrionica, and Chelobasis perplexa, to co-occur with the carabid Calophaena ligata in the same leaf roll without any sign of interspecific aggression. A comparison of host choices and the phylogeny of the hispines and of their host plants revealed no signs that beetles used species level phylogenetic relationships within the Zingiberales to select food plants. Obviously, within this plant order, rolled-leaf hispines choose their plant hosts in a nearly opportunistic manner. Seemingly, they use differences among plants at higher taxonomic levels but within the Zingiberales, the availability of

  15. Tête à Tête of Tomato Yellow Leaf Curl Virus and Tomato Yellow Leaf Curl Sardinia Virus in Single Nuclei

    PubMed Central

    Morilla, Gabriel; Krenz, Björn; Jeske, Holger; Bejarano, Eduardo R.; Wege, Christina

    2004-01-01

    Since 1997 two distinct geminivirus species, Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern Spain, and very frequently doubly infected single plants. Tomatoes as well as experimental test plants (e.g., Nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. Viral DNA accumulated to a similar extent in singly and doubly infected plants. In situ tissue hybridization showed TYLCSV and TYLCV DNAs to be confined to the phloem in both hosts, irrespective of whether they were inoculated individually or in combination. The number of infected nuclei in singly or doubly infected plants was determined by in situ hybridization of purified nuclei. The percentage of nuclei containing viral DNA (i.e., 1.4% in tomato or 6% in N. benthamiana) was the same in plants infected with either TYLCSV, TYLCV, or both. In situ hybridization of doubly infected plants, with probes that discriminate between both DNAs, revealed that at least one-fifth of infected nuclei harbored DNAs from both virus species. Such a high number of coinfected nuclei may explain why recombination between different geminivirus DNAs occurs frequently. The impact of these findings for epidemiology and for resistance breeding concerning tomato yellow leaf curl diseases is discussed. PMID:15367638

  16. A detailed analysis of the leaf rolling mutant sll2 reveals complex nature in regulation of bulliform cell development in rice (Oryza sativa L.).

    PubMed

    Zhang, J-J; Wu, S-Y; Jiang, L; Wang, J-L; Zhang, X; Guo, X-P; Wu, C-Y; Wan, J-M

    2015-03-01

    Bulliform cells are large, thin-walled and highly vacuolated cells, and play an important role in controlling leaf rolling in response to drought and high temperature. However, the molecular mechanisms regulating bulliform cell development have not been well documented. Here, we report isolation and characterisation of a rice leaf-rolling mutant, named shallot-like 2 (sll2). The sll2 plants exhibit adaxially rolled leaves, starting from the sixth leaf stage, accompanied by increased photosynthesis and reduced plant height and tiller number. Histological analyses showed shrinkage of bulliform cells, resulting in inward-curved leaves. The mutant is recessive and revertible at a rate of 9%. The leaf rolling is caused by a T-DNA insertion. Cloning of the insertion using TAIL-PCR revealed that the T-DNA was inserted in the promoter region of LOC_Os07 g38664. Unexpectedly, the enhanced expression of LOC_Os07 g38664 by the 35S enhancer in the T-DNA is not responsible for the leaf rolling phenotype. Further, the enhancer also exerted a long-distance effect, including up-regulation of several bulliform cell-related genes. sll2 suppressed the outward leaf rolling of oul1 in the sll2oul1 double mutant. We conclude that leaf rolling in sll2 could be a result of the combined effect of multi-genes, implying a complex network in regulation of bulliform cell development.

  17. A detailed analysis of the leaf rolling mutant sll2 reveals complex nature in regulation of bulliform cell development in rice (Oryza sativa L.).

    PubMed

    Zhang, J-J; Wu, S-Y; Jiang, L; Wang, J-L; Zhang, X; Guo, X-P; Wu, C-Y; Wan, J-M

    2015-03-01

    Bulliform cells are large, thin-walled and highly vacuolated cells, and play an important role in controlling leaf rolling in response to drought and high temperature. However, the molecular mechanisms regulating bulliform cell development have not been well documented. Here, we report isolation and characterisation of a rice leaf-rolling mutant, named shallot-like 2 (sll2). The sll2 plants exhibit adaxially rolled leaves, starting from the sixth leaf stage, accompanied by increased photosynthesis and reduced plant height and tiller number. Histological analyses showed shrinkage of bulliform cells, resulting in inward-curved leaves. The mutant is recessive and revertible at a rate of 9%. The leaf rolling is caused by a T-DNA insertion. Cloning of the insertion using TAIL-PCR revealed that the T-DNA was inserted in the promoter region of LOC_Os07 g38664. Unexpectedly, the enhanced expression of LOC_Os07 g38664 by the 35S enhancer in the T-DNA is not responsible for the leaf rolling phenotype. Further, the enhancer also exerted a long-distance effect, including up-regulation of several bulliform cell-related genes. sll2 suppressed the outward leaf rolling of oul1 in the sll2oul1 double mutant. We conclude that leaf rolling in sll2 could be a result of the combined effect of multi-genes, implying a complex network in regulation of bulliform cell development. PMID:25213398

  18. Alfalfa Leaf Curl Virus: an Aphid-Transmitted Geminivirus.

    PubMed

    Roumagnac, Philippe; Granier, Martine; Bernardo, Pauline; Deshoux, Maëlle; Ferdinand, Romain; Galzi, Serge; Fernandez, Emmanuel; Julian, Charlotte; Abt, Isabelle; Filloux, Denis; Mesléard, François; Varsani, Arvind; Blanc, Stéphane; Martin, Darren P; Peterschmitt, Michel

    2015-09-01

    The family Geminiviridae comprises seven genera differentiated by genome organization, sequence similarity, and insect vector. Capulavirus, an eighth genus, has been proposed to accommodate two newly discovered highly divergent geminiviruses that presently have no known vector. Alfalfa leaf curl virus, identified here as a third capulavirus, is shown to be transmitted by Aphis craccivora. This is the first report of an aphid-transmitted geminivirus. PMID:26109720

  19. [Molecular detection of tomato yellow leaf curl virus (TYLCV)].

    PubMed

    Li, Chang-Bao; Cui, Yan-Ling; Zhang, Li-Ying; Li, Chuan-You

    2012-03-01

    Tomato yellow leaf curl virus (TYLCV) is currently considered as one of the most devastating viruses in cultivated tomatoes (Solanum lycopersicum) worldwide. We reported here the development of a PCR-based method to quickly detect TYLCV using the primer pairs (TYLCV-F: 5'-ACG CAT GCC TCT AAT CCA GTG TA-3' and TYLCV-R: 5'-CCA ATA AGG CGT AAG CGT GTA GAC-3'), which was designed based on the genome sequence of TYLCV. A TYLCV-specific band of 543 bp was amplified from infected tomato plants. This protocol provides a rapid, reliable, and sensitive tool for molecular detection and identification of TYLCV in the industrial seedling and virus resistance breeding to facilitate safe and sustainable production of tomato.

  20. [Molecular detection of tomato yellow leaf curl virus (TYLCV)].

    PubMed

    Li, Chang-Bao; Cui, Yan-Ling; Zhang, Li-Ying; Li, Chuan-You

    2012-03-01

    Tomato yellow leaf curl virus (TYLCV) is currently considered as one of the most devastating viruses in cultivated tomatoes (Solanum lycopersicum) worldwide. We reported here the development of a PCR-based method to quickly detect TYLCV using the primer pairs (TYLCV-F: 5'-ACG CAT GCC TCT AAT CCA GTG TA-3' and TYLCV-R: 5'-CCA ATA AGG CGT AAG CGT GTA GAC-3'), which was designed based on the genome sequence of TYLCV. A TYLCV-specific band of 543 bp was amplified from infected tomato plants. This protocol provides a rapid, reliable, and sensitive tool for molecular detection and identification of TYLCV in the industrial seedling and virus resistance breeding to facilitate safe and sustainable production of tomato. PMID:22425956

  1. The relationship between leaf rolling and ascorbate-glutathione cycle enzymes in apoplastic and symplastic areas of Ctenanthe setosa subjected to drought stress.

    PubMed

    Saruhan, Neslihan; Terzi, Rabiye; Saglam, Aykut; Kadioglu, Asim

    2009-01-01

    The ascorbate-glutathione (ASC-GSH) cycle has an important role in defensive processes against oxidative damage generated by drought stress. In this study, the changes that take place in apoplastic and symplastic ASC-GSH cycle enzymes of the leaf and petiole were investigated under drought stress causing leaf rolling in Ctenanthe setosa (Rose.) Eichler (Marantaceae). Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate forms). Glutathione reductase (GR), a key enzyme in the GSH regeneration cycle, and ascorbate (ASC) were present in apoplastic spaces of the leaf and petiole, whereas dehydroascorbate reductase (DHAR), which uses glutathione as reductant, monodehydroascorbate reductase (MDHAR), which uses NAD(P)H as reductant, and glutathione were absent. GR, DHAR and MDHAR activities increased in the symplastic and apoplastic areas of the leaf. Apoplastic and symplastic ASC and dehydroascorbate (DHA), the oxidized form of ascorbate, rose at all scores except score 4 of symplastic ASC in the leaf. On the other hand, while reduced glutathione (GSH) content was enhanced, oxidized glutathione (GSSG) content decreased in the leaf during rolling. As for the petiole, GR activity increased in the apoplastic area but decreased in the symplastic area. DHAR and MDHAR activities increased throughout all scores, but decreased to the score 1 level at score 4. The ASC content of the apoplast increased during leaf rolling. Conversely, symplastic ASC content increased at score 2, however decreased at the later scores. While the apoplastic DHA content declined, symplastic DHA rose at score 2, but later was down to the level of score 1. While GSH content enhanced during leaf rolling, GSSG content did not change except at score 2. As well, there were good correlations between leaf rolling and ASC-GSH cycle enzyme activities in the leaf (GR and DHAR

  2. The relationship between leaf rolling and ascorbate-glutathione cycle enzymes in apoplastic and symplastic areas of Ctenanthe setosa subjected to drought stress.

    PubMed

    Saruhan, Neslihan; Terzi, Rabiye; Saglam, Aykut; Kadioglu, Asim

    2009-01-01

    The ascorbate-glutathione (ASC-GSH) cycle has an important role in defensive processes against oxidative damage generated by drought stress. In this study, the changes that take place in apoplastic and symplastic ASC-GSH cycle enzymes of the leaf and petiole were investigated under drought stress causing leaf rolling in Ctenanthe setosa (Rose.) Eichler (Marantaceae). Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate forms). Glutathione reductase (GR), a key enzyme in the GSH regeneration cycle, and ascorbate (ASC) were present in apoplastic spaces of the leaf and petiole, whereas dehydroascorbate reductase (DHAR), which uses glutathione as reductant, monodehydroascorbate reductase (MDHAR), which uses NAD(P)H as reductant, and glutathione were absent. GR, DHAR and MDHAR activities increased in the symplastic and apoplastic areas of the leaf. Apoplastic and symplastic ASC and dehydroascorbate (DHA), the oxidized form of ascorbate, rose at all scores except score 4 of symplastic ASC in the leaf. On the other hand, while reduced glutathione (GSH) content was enhanced, oxidized glutathione (GSSG) content decreased in the leaf during rolling. As for the petiole, GR activity increased in the apoplastic area but decreased in the symplastic area. DHAR and MDHAR activities increased throughout all scores, but decreased to the score 1 level at score 4. The ASC content of the apoplast increased during leaf rolling. Conversely, symplastic ASC content increased at score 2, however decreased at the later scores. While the apoplastic DHA content declined, symplastic DHA rose at score 2, but later was down to the level of score 1. While GSH content enhanced during leaf rolling, GSSG content did not change except at score 2. As well, there were good correlations between leaf rolling and ASC-GSH cycle enzyme activities in the leaf (GR and DHAR

  3. Leaf-rolling sawflies (Hymenoptera, Pamphiliidae, Pamphiliinae) of Tianmushan Mountains, Zhejiang Province, China.

    PubMed

    Shinohara, Akihiko; Wei, Mei-Cai

    2016-01-01

    Two species of Neurotoma, six species of Onycholyda, and five species of Pamphilius are recorded from Tianmushan, Zhejiang Province, China, and a key is given to these three genera and 13 species. Three new species, Onycholyda atra Shinohara & Wei, sp. nov. from Zhejiang Province, O. fulvicornis Shinohara, sp. nov. from Shaanxi Province and Zhejiang Province, and Pamphilius padus Shinohara, sp. nov. from Zhejiang Province, are described. New distribution records are: Onycholyda shaanxiana Shinohara, 1999, from Hubei Province, Zhejiang Province and Guangxi Zhuang Autonomous Region, O. subquadrata (Maa, 1944) from Zhejiang Province, O. tianmushana Shinohara & Xiao, 2006, from Hunan Province and Jiangxi Province, Pamphilius palliceps Shinohara & Xiao, 2006, from Anhui Province, P. lizejiani Shinohara in Shinohara & Wei, 2012, from Zhejiang Province, P. shengi Wei in Wei & Xiao, 1999, from Hubei Province and Zhejiang Province, and P. qinlingicus Wei in Wu & Wei, 2010, from Zhejiang Province. The larva of P. padus feeds on Padus obtusata (Rosaceae) and that of P. palliceps feeds on Rosa multiflora (Rosaceae), both singly making a leaf-roll. Rubus peltatus (Rosaceae) is recorded as a host plant of O. atra based on the observation of oviposition. PMID:27395926

  4. Association of a recombinant Cotton leaf curl Bangalore virus with yellow vein and leaf curl disease of okra in India.

    PubMed

    Venkataravanappa, V; Lakshminarayana Reddy, C N; Devaraju, A; Jalali, Salil; Krishna Reddy, M

    2013-09-01

    A begomovirus isolate (OY136A) collected from okra plants showing upward leaf curling, vein clearing, vein thickening and yellowing symptoms from Bangalore rural district, Karnataka, India was characterized. The sequence comparisons revealed that, this virus isolate share highest nucleotide identity with isolates of Cotton leaf curl Bangalore virus (CLCuBV) (AY705380) (92.8 %) and Okra enation leaf curl virus (81.1-86.2 %). This is well supported by phylogentic analysis showing, close clustering of the virus isolate with CLCuBV. With this data, based on the current taxonomic criteria for the genus Begomovirus, the present virus isolate is classified as a new strain of CLCuBV, for which CLCuBV-[India: Bangalore: okra: 2006] additional descriptor is proposed. The betasatellite (KC608158) associated with the virus is having more than 95 % sequence similarity with the cotton leaf curl betasatellites (CLCuB) available in the GenBank.The recombination analysis suggested, emergence of this new strain of okra infecting begomovirus might have been from the exchange of genetic material between BYVMV and CLCuMuV. The virus was successfully transmitted by whitefly and grafting. The host range of the virus was shown to be very narrow and limited to two species in the family Malvaceae, okra (Abelmoschus esculentus) and hollyhock (Althaea rosea), and four in the family Solanaceae.

  5. Association of a recombinant Cotton leaf curl Bangalore virus with yellow vein and leaf curl disease of okra in India.

    PubMed

    Venkataravanappa, V; Lakshminarayana Reddy, C N; Devaraju, A; Jalali, Salil; Krishna Reddy, M

    2013-09-01

    A begomovirus isolate (OY136A) collected from okra plants showing upward leaf curling, vein clearing, vein thickening and yellowing symptoms from Bangalore rural district, Karnataka, India was characterized. The sequence comparisons revealed that, this virus isolate share highest nucleotide identity with isolates of Cotton leaf curl Bangalore virus (CLCuBV) (AY705380) (92.8 %) and Okra enation leaf curl virus (81.1-86.2 %). This is well supported by phylogentic analysis showing, close clustering of the virus isolate with CLCuBV. With this data, based on the current taxonomic criteria for the genus Begomovirus, the present virus isolate is classified as a new strain of CLCuBV, for which CLCuBV-[India: Bangalore: okra: 2006] additional descriptor is proposed. The betasatellite (KC608158) associated with the virus is having more than 95 % sequence similarity with the cotton leaf curl betasatellites (CLCuB) available in the GenBank.The recombination analysis suggested, emergence of this new strain of okra infecting begomovirus might have been from the exchange of genetic material between BYVMV and CLCuMuV. The virus was successfully transmitted by whitefly and grafting. The host range of the virus was shown to be very narrow and limited to two species in the family Malvaceae, okra (Abelmoschus esculentus) and hollyhock (Althaea rosea), and four in the family Solanaceae. PMID:24426275

  6. First Report of Cucurbit yellow stunting disorder virus in California and Arizona, in association with Cucurbit leaf crumple virus and Squash leaf curl virus.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In August and September of 2006, melon plants (Cucumis melo L.) near Niland in California’s Imperial Valley and near Yuma, Arizona began exhibiting interveinal chlorosis and leaf mottling and spotting symptoms resembling those resulting from infection by viruses of the genus Crinivirus, family Clost...

  7. Evaluating Weeds as Hosts of Tomato yellow leaf curl virus.

    PubMed

    Smith, Hugh A; Seijo, Teresa E; Vallad, Gary E; Peres, Natalia A; Druffel, Keri L

    2015-08-01

    Bemisia tabaci (Gennadius) biotype B transmits Tomato yellow leaf curl virus (TYLCV), which affects tomato production globally. Prompt destruction of virus reservoirs is a key component of virus management. Identification of weed hosts of TYLCV will be useful for reducing such reservoirs. The status of weeds as alternate hosts of TYLCV in Florida remains unclear. In greenhouse studies, B. tabaci adults from a colony reared on TYLCV-infected tomato were established in cages containing one of four weeds common to horticultural fields in central and south Florida. Cages containing tomato and cotton were also infested with viruliferous whiteflies as a positive control and negative control, respectively. Whitefly adults and plant tissue were tested periodically over 10 wk for the presence of TYLCV using PCR. After 10 wk, virus-susceptible tomato plants were placed in each cage to determine if whiteflies descended from the original adults were still infective. Results indicate that Bidens alba, Emilia fosbergii, and Raphanus raphanistrum are not hosts of TYLCV, and that Amaranthus retroflexus is a host.

  8. Evaluating Weeds as Hosts of Tomato yellow leaf curl virus.

    PubMed

    Smith, Hugh A; Seijo, Teresa E; Vallad, Gary E; Peres, Natalia A; Druffel, Keri L

    2015-08-01

    Bemisia tabaci (Gennadius) biotype B transmits Tomato yellow leaf curl virus (TYLCV), which affects tomato production globally. Prompt destruction of virus reservoirs is a key component of virus management. Identification of weed hosts of TYLCV will be useful for reducing such reservoirs. The status of weeds as alternate hosts of TYLCV in Florida remains unclear. In greenhouse studies, B. tabaci adults from a colony reared on TYLCV-infected tomato were established in cages containing one of four weeds common to horticultural fields in central and south Florida. Cages containing tomato and cotton were also infested with viruliferous whiteflies as a positive control and negative control, respectively. Whitefly adults and plant tissue were tested periodically over 10 wk for the presence of TYLCV using PCR. After 10 wk, virus-susceptible tomato plants were placed in each cage to determine if whiteflies descended from the original adults were still infective. Results indicate that Bidens alba, Emilia fosbergii, and Raphanus raphanistrum are not hosts of TYLCV, and that Amaranthus retroflexus is a host. PMID:26314055

  9. First report of Sugarcane yellow leaf virus infecting Columbus Grass (Sorghum almum) in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarcane yellow leaf virus (SCYLV) [genus Polerovirus, family Luteoviridae] is the causal agent of sugarcane yellow leaf disease. SCYLV is widespread in Florida where sugarcane was the only known natural host of this virus. During spring 2015, we collected (leaves or stalks) and tested several gras...

  10. Genetic diversity of sweet potato begomoviruses in the United States and identification of a natural recombinant between sweet potato leaf curl virus and sweet potato leaf curl Georgia virus.

    PubMed

    Zhang, Shuo Cheng; Ling, Kai-Shu

    2011-06-01

    In the United States, two sweet potato begomoviruses, sweet potato leaf curl virus (SPLCV) and sweet potato leaf curl Georgia virus (SPLCGV), were previously identified in Louisiana. In recent years, at least seven additional sweet potato begomoviruses have been identified in other parts of the world. In an effort to determine the genetic diversity and distribution of sweet potato begomoviruses in the U.S., we focused our efforts on molecular characterization of field-collected begomovirus isolates in two states: Mississippi and South Carolina. Using rolling-circle amplification, a total of 52 clones of the full genome were obtained. Initial inspection of alignments of the end sequences in these clones revealed a strong genetic diversity. Overall, 10 genotypes could be assigned. A majority of the isolates (50/52) in eight genotypes were shown to be closely related to SPLCV. A representative clone of each genotype was fully sequenced and analyzed. Among them, four genotypes from South Carolina with 91-92% sequence identity to the type member of SPLCV were considered a new strain, whereas four other genotypes from Mississippi with >95% sequence identity to SPLCV were considered variants. In addition, a member of a proposed new begomovirus species was identified after comparative sequence analysis of the isolate [US:SC:646B-9] from South Carolina with less than 89% sequence identity to any known begomovirus. Hence, the provisional name Sweet potato leaf curl South Carolina virus (SPLCSCV) is proposed. Moreover, a natural recombinant consisting of two distinct parental genomic sequences from SPLCV and SPLCGV was identified in the sample [US:MS:1B-3] from Mississippi. Two recombinant breakpoints were identified, one in the origin of replication and the other between C2 and C4. This knowledge about the genetic diversity of begomoviruses infecting sweet potato will likely have a major impact on PCR-based virus detection and on disease management practice through breeding

  11. Chili leaf curl betasatellite is associated with a distinct recombinant begomovirus, Pepper leaf curl Lahore virus, in Capsicum in Pakistan.

    PubMed

    Tahir, Muhammad; Haider, Muhammad Saleem; Briddon, Rob W

    2010-04-01

    Capsium spp. are an important vegetable crop cultivated through Pakistan. Leaf curl disease is the major disease of Capsicum spp. in Pakistan caused by viruses. The disease has previously been shown to be associated with begomoviruses and betasatellites. We have cloned and sequenced a begomovirus and its associated betasatellite from Capsicum originating from central Pakistan. The begomovirus isolated was distinct from all previously characterised viruses and we propose the name Pepper leaf curl Lahore virus (PepLCLV) for this new species. Comparison of the sequence of PepLCLV with previously characterised begomoviruses shows it likely to have resulted from recombination between Papaya leaf curl virus and Chili leaf curl virus (ChiLCV), two species that have previously been identified in Pakistan. The betasatellite associated with PepLCLV in Capsicum was identified as Chili leaf curl betasatellite (ChLCB). This is the first identification of a cognate begomovirus for ChLCB infecting Capsicum, although this betasatellite has been shown in association with ChiLCV infecting potato in Pakistan. PepLCLV is one of an increasing number of monopartite begomoviruses shown to be associated with a betasatellite and one of the numerous species that affect Capsicum. In view of their only having been identified in Pakistan, PepLCLV and ChLCB likely represent a geographically distinct, Capsicum adapted, begomovirus-betasatellite complex.

  12. Replication of tomato yellow leaf curl virus (TYLCV) DNA in agroinoculated leaf discs from selected tomato genotypes.

    PubMed

    Czosnek, H; Kheyr-Pour, A; Gronenborn, B; Remetz, E; Zeidan, M; Altman, A; Rabinowitch, H D; Vidavsky, S; Kedar, N; Gafni, Y

    1993-09-01

    The leaf disc agroinoculation system was applied to study tomato yellow leaf curl virus (TYLCV) replication in explants from susceptible and resistant tomato genotypes. This system was also evaluated as a potential selection tool in breeding programmes for TYLCV resistance. Leaf discs were incubated with a head-to-tail dimer of the TYLCV genome cloned into the Ti plasmid of Agrobacterium tumefaciens. In leaf discs from susceptible cultivars (Lycopersicon esculentum) TYLCV single-stranded genomic DNA and its double-stranded DNA forms appeared within 2-5 days after inoculation. Whiteflies (Bemisia tabaci) efficiently transmitted the TYLCV disease to tomato test plants following acquisition feeding on agroinoculated tomato leaf discs. This indicates that infective viral particles have been produced and have reached the phloem cells of the explant where they can be acquired by the insects. Plants regenerated from agroinfected leaf discs of sensitive tomato cultivars exhibited disease symptoms and contained TYLCV DNA concentrations similar to those present in field-infected tomato plants, indicating that TYLCV can move out from the leaf disc into the regenerating plant. Leaf discs from accessions of the wild tomato species immune to whitefly-mediated inoculation, L. chilense LA1969 and L. hirsutum LA1777, did not support TYLCV DNA replication. Leaf discs from plants tolerant to TYLCV issued from breeding programmes behaved like leaf discs from susceptible cultivars. PMID:8400142

  13. Molecular Characterization of Tomato leaf curl Palampur virus and Pepper leaf curl betasatellite Naturally Infecting Pumpkin (Cucurbita moschata) in India.

    PubMed

    Namrata, Jaiswal; Saritha, R K; Datta, D; Singh, M; Dubey, R S; Rai, A B; Rai, M

    2010-10-01

    Pumpkin cultivation in India is affected by severe incidence of a yellow vein mosaic disease. Tomato leaf curl New Delhi virus and Squash leaf curl China virus are known to be associated with this disease in India. We were able to identify a third begomovirus-Tomato leaf curl Palampur virus (ToLCPMV), from pumpkin showing typical symptoms of the disease at Varanasi based on the sequence of complete DNA-A genome of the virus. The complete DNA-A sequence of the virus shared more than 99% sequence identity with other ToLCPMV isolates available in the GenBank and clustered with them in the phylogenetic analysis. This betasatellite amplified from the same infected sample has been identified as Pepper leaf curl betasatellite (PepLCB) which also infects chilli in India. There was 92% sequence identity between the two isolates. This is the first report of natural infection of ToLCPMV on pumpkin and association of PepLCB with yellow vein mosaic disease of pumpkin in India.

  14. Senna leaf curl virus: a novel begomovirus identified in Senna occidentalis.

    PubMed

    Kumar, Jitesh; Alok, Anshu; Kumar, Jitendra; Tuli, Rakesh

    2016-09-01

    Begomoviruses are whitefly-transmitted, single-stranded DNA viruses that infect a variety of cultivated (crop) and non-cultivated (weed) plants. The present study identified a novel begomovirus and satellites (alpha- and betasatellite) in Senna occidentalis (syn. Cassia occidentalis) showing leaf curl symptoms. The begomovirus shared a maximum sequence identity of 88.6 % with french bean leaf curl virus (JQ866297), whereas the alphasatellite and the betasatellite shared identities of 98 % and 90 % with ageratum yellow vein India alphasatellite (LK054802) and papaya leaf curl betasatellite (HM143906), respectively. No other begomovirus or satellites were detected in the suspected plants. We propose to name the virus "senna leaf curl virus" (SenLCuV). PMID:27314944

  15. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan

    PubMed Central

    Zaidi, Syed Shan-e-Ali; Shafiq, Muhammad; Amin, Imran; Scheffler, Brian E.; Scheffler, Jodi A.; Briddon, Rob W.; Mansoor, Shahid

    2016-01-01

    Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the “Burewala” strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and a recombinant form of CLCuMB have consistently been identified in cotton across the major cotton growing areas of Pakistan. Unusually a bipartite isolate of the begomovirus Tomato leaf curl virus was identified in CLCuD-affected cotton recently. In the study described here we isolated the bipartite begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) from CLCuD-affected cotton. To assess the frequency and geographic occurrence of ToLCNDV in cotton, CLCuD-symptomatic cotton plants were collected from across the Punjab and Sindh provinces between 2013 and 2015. Analysis of the plants by diagnostic PCR showed the presence of CLCuKoV-Bur in all 31 plants examined and ToLCNDV in 20 of the samples. Additionally, a quantitative real-time PCR analysis of the levels of the two viruses in co-infected plants suggests that coinfection of ToLCNDV with the CLCuKoV-Bur/CLCuMB complex leads to an increase in the levels of CLCuMB, which encodes the major pathogenicity (symptom) determinant of the complex. The significance of these results are discussed. PMID:27213535

  16. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan.

    PubMed

    Zaidi, Syed Shan-E-Ali; Shafiq, Muhammad; Amin, Imran; Scheffler, Brian E; Scheffler, Jodi A; Briddon, Rob W; Mansoor, Shahid

    2016-01-01

    Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and a recombinant form of CLCuMB have consistently been identified in cotton across the major cotton growing areas of Pakistan. Unusually a bipartite isolate of the begomovirus Tomato leaf curl virus was identified in CLCuD-affected cotton recently. In the study described here we isolated the bipartite begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) from CLCuD-affected cotton. To assess the frequency and geographic occurrence of ToLCNDV in cotton, CLCuD-symptomatic cotton plants were collected from across the Punjab and Sindh provinces between 2013 and 2015. Analysis of the plants by diagnostic PCR showed the presence of CLCuKoV-Bur in all 31 plants examined and ToLCNDV in 20 of the samples. Additionally, a quantitative real-time PCR analysis of the levels of the two viruses in co-infected plants suggests that coinfection of ToLCNDV with the CLCuKoV-Bur/CLCuMB complex leads to an increase in the levels of CLCuMB, which encodes the major pathogenicity (symptom) determinant of the complex. The significance of these results are discussed. PMID:27213535

  17. First report of an alphasatellite associated with Okra enation leaf curl virus.

    PubMed

    Chandran, S A; Packialakshmi, R M; Subhalakshmi, K; Prakash, C; Poovannan, K; Nixon Prabu, A; Gopal, P; Usha, R

    2013-06-01

    An alphasatellite DNA associated with Okra enation leaf curl virus (OELCuV) which causes enation and leaf curling in okra (Abelmoschus esculentus) plants was characterized. The full-length DNA comprises 1,350 nucleotides and shows typical genome organization of an alphasatellite. It shows the highest nucleotide sequence identity (79.7 %) to Hollyhock yellow vein virus-associated symptomless alphasatellite (HoYVSLA). This is the first report of the association of an alphasatellite with OELCuV from India.

  18. Novel Synthetic Promoters from the Cestrum Yellow Leaf Curling Virus.

    PubMed

    Sahoo, Dipak Kumar; Sarkar, Shayan; Maiti, Indu B; Dey, Nrisingha

    2016-01-01

    Constitutive promoters direct gene expression uniformly in most tissues and cells at all stages of plant growth and development; they confer steady levels of transgene expression in plant cells and hence their demand is high in plant biology. The gene silencing due to promoter homology can be avoided by either using diverse promoters isolated from different plant and viral genomes or by designing synthetic promoters. The aim of this chapter was to describe the basic protocols needed to develop and analyze novel, synthetic, nearly constitutive promoters from Cestrum yellow leaf curling virus (CmYLCV) through promoter/leader deletion and activating cis-sequence analysis. We also describe the methods to evaluate the strength of the promoters efficiently in various transient expression systems like agroinfiltration assay, gene-gun method, and assay in tobacco protoplasts. Besides, the detailed methods for developing transgenic plants (tobacco and Arabidopsis) for evaluation of the promoter using the GUS reporter gene are also described. The detailed procedure for electrophoretic mobility shift assay (EMSA) coupled with super-shift EMSA analysis are also described for showing the binding of tobacco transcription factor, TGA1a to cis-elements in the CmYLCV distal promoter region. PMID:27557764

  19. Novel Synthetic Promoters from the Cestrum Yellow Leaf Curling Virus.

    PubMed

    Sahoo, Dipak Kumar; Sarkar, Shayan; Maiti, Indu B; Dey, Nrisingha

    2016-01-01

    Constitutive promoters direct gene expression uniformly in most tissues and cells at all stages of plant growth and development; they confer steady levels of transgene expression in plant cells and hence their demand is high in plant biology. The gene silencing due to promoter homology can be avoided by either using diverse promoters isolated from different plant and viral genomes or by designing synthetic promoters. The aim of this chapter was to describe the basic protocols needed to develop and analyze novel, synthetic, nearly constitutive promoters from Cestrum yellow leaf curling virus (CmYLCV) through promoter/leader deletion and activating cis-sequence analysis. We also describe the methods to evaluate the strength of the promoters efficiently in various transient expression systems like agroinfiltration assay, gene-gun method, and assay in tobacco protoplasts. Besides, the detailed methods for developing transgenic plants (tobacco and Arabidopsis) for evaluation of the promoter using the GUS reporter gene are also described. The detailed procedure for electrophoretic mobility shift assay (EMSA) coupled with super-shift EMSA analysis are also described for showing the binding of tobacco transcription factor, TGA1a to cis-elements in the CmYLCV distal promoter region.

  20. Whitefly transmission of Sweet potato leaf curl virus in sweetpotato germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweetpotato, Ipomoea batatas (L.) Lam., is among an extensive number of plant species attacked by Bemisia tabaci (Gennadius). Because this important world food crop is vegetatively propagated, it can conveniently accumulate infections by several viruses. Sweet potato leaf curl virus (SPLCV) (ssDNA...

  1. Characterization and distribution of tomato yellow margin leaf curl virus, a begomovirus from Venezuela.

    PubMed

    Nava, A; Londoño, A; Polston, J E

    2013-02-01

    A begomovirus causing mottling and leaf deformation in tomato from the State of Mérida was cloned and sequenced. The virus has a bipartite genome comprised of a DNA-A (2,572 nucleotides) and a DNA-B (2,543 nucleotides) with a genome organization typical of New World begomoviruses. Both components share a common region of 115 nucleotides with 98 % sequence identity. Phylogenetic analysis indicated that while no virus sequences were closely related, the A component was distantly related to those of two other tomato-infecting viruses, tomato leaf deformation virus and Merremia mosaic virus; and the DNA-B, to those of pepper huasteco yellow vein virus and Rhynchosia golden mosaic Yucatan virus. The DNA-A and DNA-B sequences were submitted to GenBank (accession no. AY508993 and AY508994, respectively) and later accepted by the International Committee on Taxonomy of Viruses as the genome of a member of a unique virus species with the name Tomato yellow margin leaf curl virus (TYMLCV). Tomato (Solanum lycopersicum L. 'Fl. Lanai') plants inoculated with cloned TYMLCV DNA-A and DNA-B became systemically infected and showed chlorotic margins and leaf curling. The distribution of TYMLCV in tomato-producing states in Venezuela was determined by nucleic acid spot hybridization analysis of 334 tomato leaf samples collected from ten states using a TYMLCV-specific probe and confirmed by PCR and sequencing of the PCR fragment. TYMLCV was detected in samples from the states of Aragua, Guárico, and Mérida, suggesting that TYMLCV is widely distributed in Venezuela.

  2. Host range and genetic diversity of croton yellow vein mosaic virus, a weed-infecting monopartite begomovirus causing leaf curl disease in tomato.

    PubMed

    Pramesh, D; Mandal, Bikash; Phaneendra, Chigurupati; Muniyappa, V

    2013-03-01

    Croton yellow vein mosaic virus (CYVMV) is a widely occurring begomovirus in Croton bonplandianum, a common weed in the Indian subcontinent. In this study, CYVMV (genus Begomovirus, family Geminiviridae) was transmitted by whiteflies (Bemisia tabaci) to as many as 35 plant species belonging to 11 families, including many vegetables, tobacco varieties, ornamentals and weeds. CYVMV produced bright yellow vein symptoms in croton, whereas in all the other host species, the virus produced leaf curl symptoms. CYVMV produced leaf curl in 13 tobacco species and 22 cultivars of Nicotiana tabacum and resembled tobacco leaf curl virus (TobLCV) in host reactions. However, CYVMV was distinguished from TobLCV in four differential hosts, Ageratum conyzoides, C. bonplandianum, Euphorbia geniculata and Sonchus bracyotis. The complete genome sequences of four isolates originating from northern, eastern and southern India revealed that a single species of DNA-A and a betasatellite, croton yellow vein mosaic betasatellite (CroYVMB) were associated with the yellow vein mosaic disease of croton. The sequence identity among the isolates of CYVMV DNA-A and CroYVMB occurring in diverse plant species was 91.8-97.9 % and 83.3-100 %, respectively. The CYVMV DNA-A and CroYVMB generated through rolling-circle amplification of the cloned DNAs produced typical symptoms of yellow vein mosaic and leaf curling in croton and tomato, respectively. The progeny virus from both the croton and tomato plants was transmitted successfully by B. tabaci. The present study establishes the etiology of yellow vein mosaic disease of C. bonplandianum and provides molecular evidence that a weed-infecting monopartite begomovirus causes leaf curl in tomato.

  3. Tête à tête of tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus in single nuclei.

    PubMed

    Morilla, Gabriel; Krenz, Björn; Jeske, Holger; Bejarano, Eduardo R; Wege, Christina

    2004-10-01

    Since 1997 two distinct geminivirus species, Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern Spain, and very frequently doubly infected single plants. Tomatoes as well as experimental test plants (e.g., Nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. Viral DNA accumulated to a similar extent in singly and doubly infected plants. In situ tissue hybridization showed TYLCSV and TYLCV DNAs to be confined to the phloem in both hosts, irrespective of whether they were inoculated individually or in combination. The number of infected nuclei in singly or doubly infected plants was determined by in situ hybridization of purified nuclei. The percentage of nuclei containing viral DNA (i.e., 1.4% in tomato or 6% in N. benthamiana) was the same in plants infected with either TYLCSV, TYLCV, or both. In situ hybridization of doubly infected plants, with probes that discriminate between both DNAs, revealed that at least one-fifth of infected nuclei harbored DNAs from both virus species. Such a high number of coinfected nuclei may explain why recombination between different geminivirus DNAs occurs frequently. The impact of these findings for epidemiology and for resistance breeding concerning tomato yellow leaf curl diseases is discussed. PMID:15367638

  4. Whitefly population dynamics and evaluation of whitefly-transmitted Tomato yellow leaf curl virus (TYLCV)-resistant tomato genotypes as whitefly and TYLCV reservoirs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato yellow leaf curl virus resistant tomato cultivars are a major tool for management of this economically important virus. Results presented emphasize that such resistant tomatoes can serve as virus and whitefly reservoirs and potentially influence virus epidemics....

  5. Functional Analysis of Cotton Leaf Curl Kokhran Virus/Cotton Leaf Curl Multan Betasatellite RNA Silencing Suppressors

    PubMed Central

    Saeed, Muhammad; Briddon, Rob W.; Dalakouras, Athanasios; Krczal, Gabi; Wassenegger, Michael

    2015-01-01

    In South Asia, Cotton leaf curl disease (CLCuD) is caused by a complex of phylogenetically-related begomovirus species and a specific betasatellite, Cotton leaf curl Multan betasatellite (CLCuMuB). The post-transcriptional gene silencing (PTGS) suppression activities of the transcriptional activator protein (TrAP), C4, V2 and βC1 proteins encoded by Cotton leaf curl Kokhran virus (CLCuKoV)/CLCuMuB were assessed in Nicotiana benthamiana. A variable degree of local silencing suppression was observed for each viral protein tested, with V2 protein exhibiting the strongest suppression activity and only the C4 protein preventing the spread of systemic silencing. The CLCuKoV-encoded TrAP, C4, V2 and CLCuMuB-encoded βC1 proteins were expressed in Escherichia coli and purified. TrAP was shown to bind various small and long nucleic acids including single-stranded (ss) and double-stranded (ds) RNA and DNA molecules. C4, V2, and βC1 bound ssDNA and dsDNA with varying affinities. Transgenic expression of C4 under the constitutive 35S Cauliflower mosaic virus promoter and βC1 under a dexamethasone inducible promoter induced severe developmental abnormalities in N. benthamiana. The results indicate that homologous proteins from even quite closely related begomoviruses may differ in their suppressor activity and mechanism of action. The significance of these findings is discussed. PMID:26512705

  6. Development of Cotton leaf curl virus resistant transgenic cotton using antisense ßC1 gene.

    PubMed

    Sohrab, Sayed Sartaj; Kamal, Mohammad A; Ilah, Abdul; Husen, Azamal; Bhattacharya, P S; Rana, D

    2016-05-01

    Cotton leaf curl virus (CLCuV) is a serious pathogen causing leaf curl disease and affecting the cotton production in major growing areas. The transgenic cotton (Gossypium hirsutum cv. Coker 310) plants were developed by using βC1 gene in antisense orientation gene driven by Cauliflower mosaic virus-35S promoter and nos (nopaline synthase) terminator and mediated by Agrobacterium tumefaciens transformation and somatic embryogenesis system. Molecular confirmation of the transformants was carried out by polymerase chain reaction (PCR) and Southern blot hybridization. The developed transgenic and inoculated plants remained symptomless till their growth period. In conclusion, the plants were observed as resistant to CLCuV. PMID:27081361

  7. Development of Cotton leaf curl virus resistant transgenic cotton using antisense ßC1 gene

    PubMed Central

    Sohrab, Sayed Sartaj; Kamal, Mohammad A.; Ilah, Abdul; Husen, Azamal; Bhattacharya, P.S.; Rana, D.

    2014-01-01

    Cotton leaf curl virus (CLCuV) is a serious pathogen causing leaf curl disease and affecting the cotton production in major growing areas. The transgenic cotton (Gossypium hirsutum cv. Coker 310) plants were developed by using βC1 gene in antisense orientation gene driven by Cauliflower mosaic virus-35S promoter and nos (nopaline synthase) terminator and mediated by Agrobacterium tumefaciens transformation and somatic embryogenesis system. Molecular confirmation of the transformants was carried out by polymerase chain reaction (PCR) and Southern blot hybridization. The developed transgenic and inoculated plants remained symptomless till their growth period. In conclusion, the plants were observed as resistant to CLCuV. PMID:27081361

  8. Genetic transformation with untranslatable coat protein gene of sugarcane yellow leaf virus reduces virus titers in sugarcane.

    PubMed

    Zhu, Yun J; McCafferty, Heather; Osterman, Greg; Lim, Steven; Agbayani, Ricelle; Lehrer, Axel; Schenck, Susan; Komor, Ewald

    2011-06-01

    Sugarcane yellow leaf syndrome, characterized by a yellowing of the leaf midrib followed by leaf necrosis and growth suppression, is caused by sugarcane yellow leaf virus (SCYLV). We produced SCYLV-resistant transgenic sugarcane from a susceptible cultivar (H62-4671) and determined the amount of virus present following inoculation. The transgenic plants were produced through biolistic bombardment of cell cultures with an untranslatable coat protein gene. Presence of the transgene in regenerated plants was confirmed using PCR and Southern blot analysis. The transgenic lines were inoculated by viruliferous aphids and the level of SCYLV in the plants was determined. Six out of nine transgenic lines had at least 10(3)-fold lower virus titer than the non-transformed, susceptible parent line. This resistance level, as measured by virus titer and symptom development, was similar to that of a resistant cultivar (H78-4153). The selected SCYLV-resistant transgenic sugarcane lines will be available for integration of the resistance gene into other commercial cultivars and for quantification of viral effects on yield. PMID:20661641

  9. Differentiation of Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus using real-time TaqMan PCR.

    PubMed

    Papayiannis, L C; Iacovides, T A; Katis, N I; Brown, J K

    2010-05-01

    During the past four decades, Tomato yellow leaf curl disease has become one of the major constraints in tomato production worldwide. In the Mediterranean basin, several isolates from two major Begomovirus species are involved in outbreaks and persistent epidemics. A real-time TaqMan PCR assay was developed and evaluated for the rapid and multiplex detection and differentiation of two begomoviruses often found in mixed infections in the region, Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV). This assay was 1000-fold more sensitive than conventional PCR assays described previously, allowing the use of simple template preparation methods and eliminating the need for total nucleic acid purification. The viral DNA template was obtained by spotting sap extract derived from TYLCV or TYLCSV infected tissues on a nylon membrane or by directly using crude plant extracts in the real-time reaction cocktail. Preliminary results showed that this method can successfully detect and discriminate virus species from infected tomato, bean, pepper and different weed species obtained from the Mediterranean basin, the USA and Japan, allowing the simple, fast and cost-effective testing of a large number of samples in certification schemes. The assay can also be used for the detection of these two begomovirus species in their whitefly vector biotypes of the Bemisia tabaci (Gennadius) species group.

  10. Replication of Tomato Yellow Leaf Curl Virus in Its Whitefly Vector, Bemisia tabaci

    PubMed Central

    Pakkianathan, Britto Cathrin; Kontsedalov, Svetlana; Lebedev, Galina; Mahadav, Assaf; Zeidan, Muhammad; Czosnek, Henryk

    2015-01-01

    ABSTRACT Tomato yellow leaf curl virus (TYLCV) is a begomovirus transmitted exclusively by the whitefly Bemisia tabaci in a persistent, circulative manner. Replication of TYLCV in its vector remains controversial, and thus far, the virus has been considered to be nonpropagative. Following 8 h of acquisition on TYLCV-infected tomato plants or purified virions and then transfer to non-TYLCV-host cotton plants, the amounts of virus inside whitefly adults significantly increased (>2-fold) during the first few days and then continuously decreased, as measured by the amounts of genes on both virus DNA strands. Reported alterations in insect immune and defense responses upon virus retention led us to hypothesize a role for the immune response in suppressing virus replication. After virus acquisition, stress conditions were imposed on whiteflies, and the levels of three viral gene sequences were measured over time. When whiteflies were exposed to TYLCV and treatment with two different pesticides, the virus levels continuously increased. Upon exposure to heat stress, the virus levels gradually decreased, without any initial accumulation. Switching of whiteflies between pesticide, heat stress, and control treatments caused fluctuating increases and decreases in virus levels. Fluorescence in situ hybridization analysis confirmed these results and showed virus signals inside midgut epithelial cell nuclei. Combining the pesticide and heat treatments with virus acquisition had significant effects on fecundity. Altogether, our results demonstrate for the first time that a single-stranded DNA plant virus can replicate in its hemipteran vector. IMPORTANCE Plant viruses in agricultural crops are of great concern worldwide. Many of them are transmitted from infected to healthy plants by insects. Persistently transmitted viruses often have a complex association with their vectors; however, most are believed not to replicate within these vectors. Such replication is important, as it

  11. A new strain of tomato severe leaf curl virus and a unique variant of tomato yellow leaf curl virus from Mexico.

    PubMed

    Bañuelos-Hernández, B; Mauricio-Castillo, J A; Cardenas-Conejo, Y; Guevara-González, R G; Arguello-Astorga, G R

    2012-09-01

    The complete genome sequence of a distinct variant of tomato yellow leaf curl virus-Israel (TYLCV-IL) and the DNA-A sequence of a new strain of tomato severe leaf curl virus (ToSLCV) isolated in San Luis Potosi, Mexico, are described and analyzed. The TYLCV-IL[MX:SLP:11] variant differs from all TYLCV-IL isolates described so far by a unique 42-nt duplicated sequence comprising a part of the conserved stem-loop element of the virion-strand replication origin and adjacent regulatory sequences. TYLCV-IL[MX:SLP:11] was associated with tomato chino La Paz virus (ToChLPV-B[MX:SLP:11]) in a Solanum pimpinellifolium plant, and with pepper huasteco yellow vein virus (PHYVV-[MX:SLP:11]) and ToSLCV-GT[MX:SLP:11] in a Solanum lycopersicum plant. In addition, a distinct ToSLCV exhibiting low sequence identity (<89 %) to other ToSLCV isolates from Mexico was found in a tomato plant collected in the same field. Sequence analysis of this new ToSLCV strain indicates that it is a recombinant of close relatives of ToSLCV-GT[MX:SLP:11] and ToChLPV-B[MX:SLP:11] found in mixed infections with TYLCV-IL[MX:SLP:11].

  12. Molecular diversity of cotton leaf curl Gezira virus isolates and their satellite DNAs associated with okra leaf curl disease in Burkina Faso.

    PubMed

    Tiendrébéogo, Fidèle; Lefeuvre, Pierre; Hoareau, Murielle; Villemot, Julie; Konaté, Gnissa; Traoré, Alfred S; Barro, Nicolas; Traoré, Valentin S; Reynaud, Bernard; Traoré, Oumar; Lett, Jean-Michel

    2010-02-23

    Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production and is widespread in Africa. Using a large number of samples representative of the major growing regions in Burkina Faso (BF), we show that the disease is associated with a monopartite begomovirus and satellite DNA complexes. Twenty-three complete genomic sequences of Cotton leaf curl Gezira virus (CLCuGV) isolates associated with OLCD, sharing 95 to 99% nucleotide identity, were cloned and sequenced. Six betasatellite and four alphasatellite (DNA-1) molecules were also characterized. The six isolates of betasatellite associated with CLCuGV isolates correspond to Cotton leaf curl Gezira betasatellite (CLCuGB) (88 to 98% nucleotide identity). One isolate of alphasatellite is a variant of Cotton leaf curl Gezira alphasatellite (CLCuGA) (89% nucleotide identity), whereas the three others isolates appear to correspond to a new species of alphasatellite (CLCuGA most similar sequence present 52 to 60% nucleotide identity), provisionally named Okra leaf curl Burkina Faso alphasatellite (OLCBFA). Recombination analysis of the viruses demonstrated the interspecies recombinant origin of all CLCuGV isolates, with parents being close to Hollyhock leaf crumple virus (AY036009) and Tomato leaf curl Diana virus (AM701765). Combined with the presence of satellites DNA, these results highlight the complexity of begomoviruses associated with OLCD.

  13. Papaya is not a host for Tomato Yellow Leaf Curl Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of tomato production is threatened by tomato yellow leaf-curl virus TYLCV and its vector, the silverleaf whitefly Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae). Use of papaya Carica papaya L. as a banker plant for a whitefly parasitoid shows promise as a whitefly m...

  14. Identification of a distinct strain of cotton leaf curl Burewala virus.

    PubMed

    Shuja, Malik Nawaz; Briddon, Rob W; Tahir, Muhammad

    2014-10-01

    Cotton leaf curl disease (CLCuD) is the major biotic limitation to cotton production in Pakistan and northwestern India. The disease is caused by various distinct viruses of the genus Begomovirus (family Geminiviridae) in association with a disease-specific betasatellite - cotton leaf curl Multan betasatellite (CLCuMB). Since 2001, when resistance to CLCuD in cotton was broken, only one virus was consistently identified in cotton exhibiting CLCuD symptoms in Punjab province (Pakistan) - cotton leaf curl Burewala virus (CLCuBuV). An analysis of all CLCuBuV isolates available in the databases showed these to represent only a single strain, based on currently applicable criteria. Virus and betasatellite clones were obtained from a leaf sample (isolate C49) collected from a CLCuD symptomatic cotton plant in Layyah district, Punjab province, in 2012. Analysis of the sequence of the betasatellite showed this to be an isolate of CLCuMB containing the recombinant fragment typical of this satellite post-resistance-breaking. The virus was shown it to be an isolate of CLCuBuV but to be distinct from all previously characterised isolates and to represent a distinct strain. In common with previous CLCuBuV isolates, the virus from C49 is a recombinant containing sequences derived from viruses of two species that were prevalent in cotton pre-resistance-breaking but with distinct recombination break sites. As was the case with the earlier CLCuBuV, the newly identified strain of CLCuBuV lacks an intact transcriptional activator protein.

  15. Quantification and Localization of Watermelon Chlorotic Stunt Virus and Tomato Yellow Leaf Curl Virus (Geminiviridae) in Populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with Differential Virus Transmission Characteristics

    PubMed Central

    Kollenberg, Mario; Winter, Stephan; Götz, Monika

    2014-01-01

    Bemisia tabaci (Gennadius) is one of the economically most damaging insects to crops in tropical and subtropical regions. Severe damage is caused by feeding and more seriously by transmitting viruses. Those of the genus begomovirus (Geminiviridae) cause the most significant crop diseases and are transmitted by B. tabaci in a persistent circulative mode, a process which is largely unknown. To analyze the translocation and to identify critical determinants for transmission, two populations of B. tabaci MEAM1 were compared for transmitting Watermelon chlorotic stunt virus (WmCSV) and Tomato yellow leaf curl virus (TYLCV). Insect populations were chosen because of their high and respectively low virus transmission efficiency to compare uptake and translocation of virus through insects. Both populations harbored Rickettsia, Hamiltonella and Wolbachia in comparable ratios indicating that endosymbionts might not contribute to the different transmission rates. Quantification by qPCR revealed that WmCSV uptake and virus concentrations in midguts and primary salivary glands were generally higher than TYLCV due to higher virus contents of the source plants. Both viruses accumulated higher in insects from the efficiently compared to the poorly transmitting population. In the latter, virus translocation into the hemolymph was delayed and virus passage was impeded with limited numbers of viruses translocated. FISH analysis confirmed these results with similar virus distribution found in excised organs of both populations. No virus accumulation was found in the midgut lumen of the poor transmitter because of a restrained virus translocation. Results suggest that the poorly transmitting population comprised insects that lacked transmission competence. Those were selected to develop a population that lacks virus transmission. Investigations with insects lacking transmission showed that virus concentrations in midguts were reduced and only negligible virus amounts were found at the

  16. Quantification and localization of Watermelon chlorotic stunt virus and Tomato yellow leaf curl virus (Geminiviridae) in populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with differential virus transmission characteristics.

    PubMed

    Kollenberg, Mario; Winter, Stephan; Götz, Monika

    2014-01-01

    Bemisia tabaci (Gennadius) is one of the economically most damaging insects to crops in tropical and subtropical regions. Severe damage is caused by feeding and more seriously by transmitting viruses. Those of the genus begomovirus (Geminiviridae) cause the most significant crop diseases and are transmitted by B. tabaci in a persistent circulative mode, a process which is largely unknown. To analyze the translocation and to identify critical determinants for transmission, two populations of B. tabaci MEAM1 were compared for transmitting Watermelon chlorotic stunt virus (WmCSV) and Tomato yellow leaf curl virus (TYLCV). Insect populations were chosen because of their high and respectively low virus transmission efficiency to compare uptake and translocation of virus through insects. Both populations harbored Rickettsia, Hamiltonella and Wolbachia in comparable ratios indicating that endosymbionts might not contribute to the different transmission rates. Quantification by qPCR revealed that WmCSV uptake and virus concentrations in midguts and primary salivary glands were generally higher than TYLCV due to higher virus contents of the source plants. Both viruses accumulated higher in insects from the efficiently compared to the poorly transmitting population. In the latter, virus translocation into the hemolymph was delayed and virus passage was impeded with limited numbers of viruses translocated. FISH analysis confirmed these results with similar virus distribution found in excised organs of both populations. No virus accumulation was found in the midgut lumen of the poor transmitter because of a restrained virus translocation. Results suggest that the poorly transmitting population comprised insects that lacked transmission competence. Those were selected to develop a population that lacks virus transmission. Investigations with insects lacking transmission showed that virus concentrations in midguts were reduced and only negligible virus amounts were found at the

  17. Survey of apple chlorotic leaf spot virus and apple stem grooving virus occurrence in Korea and frequency of mixed infections in apple

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the absence of knowledge of the distribution of Apple stem grooving virus (ASGV) and Apple chlorotic leaf spot virus (ACLSV) in apples in Korea, we carried out a survey for these viruses in Gyeongsang and Chungcheong provinces in 2014. A total of 65 samples were collected and tested by RT-PCR...

  18. Transcriptome analysis to identify differentially expressed genes associated with ty-5 against tomato yellow leaf curl virus and Sw-7 against tomato spotted wilt virus in tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato yellow leaf curl virus (TYLCV) and Tomato spotted wilt virus (TSWV) are two of the most economically important viruses on tomato (Solanum lycopersicum) worldwide. Developing a cultivar with resistance would be the most effective and economical means for viral disease management. However, id...

  19. Biology and management of sugarcane yellow leaf virus: an historical overview.

    PubMed

    ElSayed, Abdelaleim Ismail; Komor, Ewald; Boulila, Moncef; Viswanathan, Rasappa; Odero, Dennis C

    2015-12-01

    Sugarcane yellow leaf virus (SCYLV) is one of the most widespread viruses causing disease in sugarcane worldwide. The virus has been responsible for drastic economic losses in most sugarcane-growing regions and remains a major concern for sugarcane breeders. Infection with SCYLV results in intense yellowing of the midrib, which extends to the leaf blade, followed by tissue necrosis from the leaf tip towards the leaf base. Such symptomatic leaves are usually characterized by increased respiration, reduced photosynthesis, a change in the ratio of hexose to sucrose, and an increase in starch content. SCYLV infection affects carbon assimilation and metabolism in sugarcane, resulting in stunted plants in severe cases. SCYLV is mainly propagated by planting cuttings from infected stalks. Phylogenetic analysis has confirmed the worldwide distribution of at least eight SCYLV genotypes (BRA, CHN1, CHN3, CUB, HAW, IND, PER, and REU). Evidence of recombination has been found in the SCYLV genome, which contains potential recombination signals in ORF1/2 and ORF5. This shows that recombination plays an important role in the evolution of SCYLV.

  20. Biology and management of sugarcane yellow leaf virus: an historical overview.

    PubMed

    ElSayed, Abdelaleim Ismail; Komor, Ewald; Boulila, Moncef; Viswanathan, Rasappa; Odero, Dennis C

    2015-12-01

    Sugarcane yellow leaf virus (SCYLV) is one of the most widespread viruses causing disease in sugarcane worldwide. The virus has been responsible for drastic economic losses in most sugarcane-growing regions and remains a major concern for sugarcane breeders. Infection with SCYLV results in intense yellowing of the midrib, which extends to the leaf blade, followed by tissue necrosis from the leaf tip towards the leaf base. Such symptomatic leaves are usually characterized by increased respiration, reduced photosynthesis, a change in the ratio of hexose to sucrose, and an increase in starch content. SCYLV infection affects carbon assimilation and metabolism in sugarcane, resulting in stunted plants in severe cases. SCYLV is mainly propagated by planting cuttings from infected stalks. Phylogenetic analysis has confirmed the worldwide distribution of at least eight SCYLV genotypes (BRA, CHN1, CHN3, CUB, HAW, IND, PER, and REU). Evidence of recombination has been found in the SCYLV genome, which contains potential recombination signals in ORF1/2 and ORF5. This shows that recombination plays an important role in the evolution of SCYLV. PMID:26424197

  1. Evolutionary and molecular aspects of Indian tomato leaf curl virus coat protein.

    PubMed

    Kumar, Sivakumar Prasanth; Patel, Saumya K; Kapopara, Ravi G; Jasrai, Yogesh T; Pandya, Himanshu A

    2012-01-01

    Tomato leaf curl disease (ToLCD) is manifested by yellowing of leaf lamina with upward leaf curl, leaf distortion, shrinking of the leaf surface, and stunted plant growth caused by tomato leaf curl virus (ToLCV). In the present study, using computational methods we explored the evolutionary and molecular prospects of viral coat protein derived from an isolate of Vadodara district, Gujarat (ToLCGV-[Vad]), India. We found that the amino acids in coat protein required for systemic infection, viral particle formation, and insect transmission to host cells were conserved amongst Indian strains. Phylogenetic studies on Indian ToLCV coat proteins showed evolutionary compatibility with other viral taxa. Modeling of coat protein revealed a topology similar to characteristic Geminate viral particle consisting of antiparallel β-barrel motif with N-terminus α-helix. The molecular interaction of coat protein with the viral DNA required for encapsidation and nuclear shuttling was investigated through sequence- and structure-based approaches. We further emphasized the role of loops in coat protein structure as molecular recognition interface.

  2. OsMYB103L, an R2R3-MYB transcription factor, influences leaf rolling and mechanical strength in rice (Oryza sativa L.)

    PubMed Central

    2014-01-01

    Background The shape of grass leaves possesses great value in both agronomy and developmental biology research. Leaf rolling is one of the important traits in rice (Oryza sativa L.) breeding. MYB transcription factors are one of the largest gene families and have important roles in plant development, metabolism and stress responses. However, little is known about their functions in rice. Results In this study, we report the functional characterization of a rice gene, OsMYB103L, which encodes an R2R3-MYB transcription factor. OsMYB103L was localized in the nucleus with transactivation activity. Overexpression of OsMYB103L in rice resulted in a rolled leaf phenotype. Further analyses showed that expression levels of several cellulose synthase genes (CESAs) were significantly increased, as was the cellulose content in OsMYB103L overexpressing lines. Knockdown of OsMYB103L by RNA interference led to a decreased level of cellulose content and reduced mechanical strength in leaves. Meanwhile, the expression levels of several CESA genes were decreased in these knockdown lines. Conclusions These findings suggest that OsMYB103L may target CESA genes for regulation of cellulose synthesis and could potentially be engineered for desirable leaf shape and mechanical strength in rice. PMID:24906444

  3. A Rapid and Efficient Method for Construction of an Infectious Clone of Tomato yellow leaf curl virus.

    PubMed

    Bang, Bongjun; Lee, Jongyun; Kim, Sunyoung; Park, Jungwook; Nguyen, Thao Thi; Seo, Young-Su

    2014-09-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is responsible for one of the most devastating viral diseases in tomato-growing countries and is becoming a serious problem in many subtropical and tropical countries. The climate in Korea is getting warmer and developing subtropical features in response to global warming. These changes are being accompanied by TYLCV, which is now becoming a large problem in the Korean tomato industry. The most effective way to reduce damage caused by TYLCV is to breed resistant varieties of tomatoes. To accomplish this, it is necessary to establish a simple inoculation technique for the efficient evaluation of resistance to TYLCV. Here, we present the rolling circle amplification (RCA) method, which employs a bacteriophage using phi-29 DNA polymerase for construction of infectious TYLCV clones. The RCA method is simple, does not require sequence information for cloning, and is less expensive and time consuming than conventional PCR based-methods. Furthermore, RCA-based construction of an infectious clone can be very useful to other emerging and unknown geminiviruses in Korea. PMID:25289018

  4. A Rapid and Efficient Method for Construction of an Infectious Clone of Tomato yellow leaf curl virus

    PubMed Central

    Bang, Bongjun; Lee, Jongyun; Kim, Sunyoung; Park, Jungwook; Nguyen, Thao Thi; Seo, Young-Su

    2014-01-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is responsible for one of the most devastating viral diseases in tomato-growing countries and is becoming a serious problem in many subtropical and tropical countries. The climate in Korea is getting warmer and developing subtropical features in response to global warming. These changes are being accompanied by TYLCV, which is now becoming a large problem in the Korean tomato industry. The most effective way to reduce damage caused by TYLCV is to breed resistant varieties of tomatoes. To accomplish this, it is necessary to establish a simple inoculation technique for the efficient evaluation of resistance to TYLCV. Here, we present the rolling circle amplification (RCA) method, which employs a bacteriophage using phi-29 DNA polymerase for construction of infectious TYLCV clones. The RCA method is simple, does not require sequence information for cloning, and is less expensive and time consuming than conventional PCR based-methods. Furthermore, RCA-based construction of an infectious clone can be very useful to other emerging and unknown geminiviruses in Korea. PMID:25289018

  5. Molecular variability and evolution of a natural population of tomato yellow leaf curl virus in Shanghai, China.

    PubMed

    Yang, Xiu-ling; Zhou, Meng-ning; Qian, Ya-juan; Xie, Yan; Zhou, Xue-ping

    2014-02-01

    Tomato yellow leaf curl virus (TYLCV), belonging to the genus Begomovirus of the family Geminiviridae, is emerging as the most destructive pathogen of tomato plants. Since the first report of TYLCV in Shanghai, China in 2006, TYLCV has spread rapidly to 13 provinces or autonomous regions of China. In this study, the molecular variability and evolution of TYLCV were monitored in Shanghai from its first upsurge in 2006 until 2010. Full-length genomic sequences of 26 isolates were obtained by rolling circle amplification. Sequence analysis showed that the intergenic region was the most variable, with a mean mutation rate of 4.81×10(-3) nucleotide substitutions per site per year. Genetic differentiation was found within isolates obtained from 2006, 2009, and 2010, though a linear increase in genetic diversity over time was not evident. Whilst significant parts of TYLCV genes were under negative selection, the C4 gene embedded entirely within the C1 gene had a tendency to undergo positive selection. Our results indicate that a mechanism of independent evolution of overlapping regions could apply to the natural population of TYLCV in Shanghai, China. PMID:24510706

  6. Antiviral effect of flavonol glycosides isolated from the leaf of Zanthoxylum piperitum on influenza virus.

    PubMed

    Ha, Song-Yi; Youn, Hana; Song, Chang-Seon; Kang, Se Chan; Bae, Jong Jin; Kim, Hee Tae; Lee, Kwang Min; Eom, Tae Hoon; Kim, In Su; Kwak, Jong Hwan

    2014-04-01

    The ethanol extract of Zanthoxylum piperitum (L.) DC. showed in vitro antiviral activity against influenza A virus. Three flavonol glycosides were isolated from the EtOAc fraction of Z. piperitum leaf by means of activity-guided chromatographic separation. Structures of isolated compounds were identified as quercetin 3-O-β-D-galactopyranoside (1), quercetin 3-O-α-L-rhamnopyranoside (2), kaempferol 3-O-α-L-rhamnopyranoside (3) by comparing their spectral data with literature values. The anti-influenza viral activity of isolates was evaluated using a plaque reduction assay against influenza A/NWS/33 (H1N1) virus. The compounds also were subjected to neuraminidase inhibition assay in influenza A/NWS/33 virus. Compounds 1-3 exhibited antiviral activity against an influenza A virus in vitro, and inhibited the neuraminidase activity at relatively high concentrations.

  7. Only minimal regions of tomato yellow leaf curl virus (TYLCV) are required for replication, expression and movement.

    PubMed

    Gover, Ofer; Peretz, Yuval; Mozes-Koch, Rita; Maori, Eyal; Rabinowitch, Haim D; Sela, Ilan

    2014-09-01

    The IL-60 platform, consisting of a disarmed form of tomato yellow leaf curl virus (TYLCV) and auxiliary components, was previously developed as a nontransgenic universal vector system for gene expression and silencing that can express an entire operon in plants. IL-60 does not allow rolling-circle replication; hence, production of viral single-stranded (ss) DNA progeny is prevented. We used this double-stranded (ds) DNA-restricted platform (uncoupled from the dsDNA→ssDNA replication phase of progeny viral DNA) for functional genomics studies of TYLCV. We report that the noncoding 314-bp intergenic region (IR) is the only viral element required for viral dsDNA replication. None of the viral genes are required, suggesting recruitment of host factors that recognize the IR. We further show that IR-carrying reporter genes are also capable of replication but remain confined to the cells into which they were introduced. Only two sense-oriented viral genes (V1 and V2) need to be added to the IR-carrying construct for expression and movement. Hence, any IR-dsDNA construct supplemented with V1 and V2 becomes a replication-competent, mobile and expressing plant plasmid. All viral functions (replication, expression and movement) are determined by the IR and the sense-oriented genes. The complementary-oriented viral genes have auxiliary roles in the late phase of the virus "life cycle". The previously reported involvement of some viral genes in expression and movement is therefore revised. PMID:24719195

  8. Newly identified RNAs of raspberry leaf blotch virus encoding a related group of proteins.

    PubMed

    Lu, Yuwen; McGavin, Wendy; Cock, Peter J A; Schnettler, Esther; Yan, Fei; Chen, Jianping; MacFarlane, Stuart

    2015-11-01

    Members of the genus Emaravirus, including Raspberry leaf blotch virus (RLBV), are enveloped plant viruses with segmented genomes of negative-strand RNA, although the complete genome complement for any of these viruses is not yet clear. Currently, wheat mosaic virus has the largest emaravirus genome comprising eight RNAs. Previously, we identified five genomic RNAs for RLBV; here, we identify a further three RNAs (RNA6-8). RNA6-8 encode proteins that have clear homologies to one another, but not to any other emaravirus proteins. The proteins self-interacted in yeast two-hybrid and bimolecular fluorescence complementation (BiFC) experiments, and the P8 protein interacted with the virus nucleocapsid protein (P3) using BiFC. Expression of two of the proteins (P6 and P7) using potato virus X led to an increase in virus titre and symptom severity, suggesting that these proteins may play a role in RLBV pathogenicity; however, using two different tests, RNA silencing suppression activity was not detected for any of the RLBV proteins encoded by RNA2-8.

  9. Quantification of sugarcane yellow leaf virus in sugarcane following transmission through aphid vector, Melanaphis sacchari.

    PubMed

    Chinnaraja, C; Viswanathan, R

    2015-12-01

    Yellow leaf caused by Sugarcane yellow leaf virus (SCYLV) is a serious constraint to sugarcane production in India and currently the disease epidemics occur on many of the susceptible varieties under field conditions. Studies were conducted on the virus transmission by sugarcane aphid Melanaphis sacchari in sugarcane by inoculating virus-free meristem derived from micro- propagated plants of sugarcane cv Co 86032 with viruliferous aphids. Virus transmission was confirmed through RT-PCR assays and subsequently SCYLV population was established through RT-qPCR. A maximum of 22.3 × 10(3), 3.16 × 10(6) and 4.78 × 10(6) copies of SCYLV-RNA targets were recorded in the plants after 7, 180 and 300 days, respectively. This study showed that the aphid species M. sacchari acts as an effective vector of SCYLV. The relative standard curve method in RT-qPCR efficiently detected the increment in SCYLV copy numbers in sugarcane following transmission through M. sacchari.

  10. Complete nucleotide sequence of rose yellow leaf virus, a new member of the family Tombusviridae.

    PubMed

    Mollov, Dimitre; Lockhart, Ben; Zlesak, David C

    2014-10-01

    The genome of the rose yellow leaf virus (RYLV) has been determined to be 3918 nucleotides long and to contain seven open reading frames (ORFs). ORF1 encodes a 27-kDa peptide (p27). ORF2 shares a common start codon with ORF1 and continues through the amber stop codon of p27 to encode an 87-kDa (p87) protein that has amino acid similarity to the RNA-dependent RNA polymerase (RdRp) of members of the family Tombusviridae. ORFs 3 and 4 have no significant amino acid similarity to known functional viral ORFs. ORF5 encodes a 6-kDa (p6) protein that has similarity to movement proteins of members of the Tombusviridae. ORF5A has no conventional start codon and overlaps with p6. A putative +1 frameshift mechanism allows p6 translation to continue through the stop codon and results in a 12-kDa protein that has high homology to the carmovirus p13 movement protein. The 37-kDa protein encoded by ORF6 has amino acid sequence similarity to coat proteins (CP) of members of the Tombusviridae. ORF7 has no significant amino acid similarity to known viral ORFs. Phylogenetic analysis of the RdRp amino acid sequences grouped RYLV together with the unclassified Rosa rugosa leaf distortion virus (RrLDV), pelargonium line pattern virus (PLPV), and pelargonium chlorotic ring pattern virus (PCRPV) in a distinct subgroup of the family Tombusviridae. PMID:24838852

  11. Quantification of sugarcane yellow leaf virus in sugarcane following transmission through aphid vector, Melanaphis sacchari.

    PubMed

    Chinnaraja, C; Viswanathan, R

    2015-12-01

    Yellow leaf caused by Sugarcane yellow leaf virus (SCYLV) is a serious constraint to sugarcane production in India and currently the disease epidemics occur on many of the susceptible varieties under field conditions. Studies were conducted on the virus transmission by sugarcane aphid Melanaphis sacchari in sugarcane by inoculating virus-free meristem derived from micro- propagated plants of sugarcane cv Co 86032 with viruliferous aphids. Virus transmission was confirmed through RT-PCR assays and subsequently SCYLV population was established through RT-qPCR. A maximum of 22.3 × 10(3), 3.16 × 10(6) and 4.78 × 10(6) copies of SCYLV-RNA targets were recorded in the plants after 7, 180 and 300 days, respectively. This study showed that the aphid species M. sacchari acts as an effective vector of SCYLV. The relative standard curve method in RT-qPCR efficiently detected the increment in SCYLV copy numbers in sugarcane following transmission through M. sacchari. PMID:26645033

  12. Infection of the whitefly Bemisia tabaci with Rickettsia spp. alters its interactions with Tomato yellow leaf curl virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. Here we report that infection with Rickettsia spp., a facultative endosymbiont of whiteflies...

  13. Tomato yellow leaf curl virus: No evidence for replication in the insect vector Bemisia tabaci

    PubMed Central

    Sánchez-Campos, Sonia; Rodríguez-Negrete, Edgar A.; Cruzado, Lucía; Grande-Pérez, Ana; Bejarano, Eduardo R.; Navas-Castillo, Jesús; Moriones, Enrique

    2016-01-01

    Begomovirus ssDNA plant virus (family Geminiviridae) replication within the Bemisia tabaci vector is controversial. Transovarial transmission, alteration to whitefly biology, or detection of viral transcripts in the vector are proposed as indirect evidence of replication of tomato yellow leaf curl virus (TYLCV). Recently, contrasting direct evidence has been reported regarding the capacity of TYLCV to replicate within individuals of B. tabaci based on quantitave PCR approaches. Time-course experiments to quantify complementary and virion sense viral nucleic acid accumulation within B. tabaci using a recently implemented two step qPCR procedure revealed that viral DNA quantities did not increase for time points up to 96 hours after acquisition of the virus. Our findings do not support a recent report claiming TYLCV replication in individuals of B. tabaci. PMID:27476582

  14. Tomato yellow leaf curl virus: No evidence for replication in the insect vector Bemisia tabaci.

    PubMed

    Sánchez-Campos, Sonia; Rodríguez-Negrete, Edgar A; Cruzado, Lucía; Grande-Pérez, Ana; Bejarano, Eduardo R; Navas-Castillo, Jesús; Moriones, Enrique

    2016-01-01

    Begomovirus ssDNA plant virus (family Geminiviridae) replication within the Bemisia tabaci vector is controversial. Transovarial transmission, alteration to whitefly biology, or detection of viral transcripts in the vector are proposed as indirect evidence of replication of tomato yellow leaf curl virus (TYLCV). Recently, contrasting direct evidence has been reported regarding the capacity of TYLCV to replicate within individuals of B. tabaci based on quantitave PCR approaches. Time-course experiments to quantify complementary and virion sense viral nucleic acid accumulation within B. tabaci using a recently implemented two step qPCR procedure revealed that viral DNA quantities did not increase for time points up to 96 hours after acquisition of the virus. Our findings do not support a recent report claiming TYLCV replication in individuals of B. tabaci. PMID:27476582

  15. Analysis of watermelon chlorotic stunt virus and tomato leaf curl Palampur virus mixed and pseudo-recombination infections.

    PubMed

    Esmaeili, Maryam; Heydarnejad, Jahangir; Massumi, Hossain; Varsani, Arvind

    2015-12-01

    Watermelon chlorotic stunt virus (WmCSV) and tomato leaf curl Palampur virus (ToLCPMV) are limiting factors for cucurbit production in south and southeastern Iran. ToLCPMV infects all cucurbit crops (except watermelons) whereas WmCSV is somewhat limited to watermelon, causing detrimental effects on fruit production. In a survey, we detected WmCSV in all watermelon growing farms in Fars province (southern Iran). Given that WmCSV and ToLCPMV are present in the same geographical location in Iran, we studied the interaction of two viruses. Co-infection using agroinfectious clones of WmCSV and ToLCPMV caused severe symptoms in watermelon and zucchini in comparison to symptoms observed from individual infections. Interestingly, inoculation of zucchini with WmCSV DNA-A and ToLCPMV DNA-B agroinfectious clones or vice versa produced a viable pseudo-recombinant and induced systemic symptoms. This demonstrates that replication-associated protein of DNA-A of each virus is able to bind to cis elements of the DNA-B molecules of another virus. PMID:26433951

  16. Analysis of watermelon chlorotic stunt virus and tomato leaf curl Palampur virus mixed and pseudo-recombination infections.

    PubMed

    Esmaeili, Maryam; Heydarnejad, Jahangir; Massumi, Hossain; Varsani, Arvind

    2015-12-01

    Watermelon chlorotic stunt virus (WmCSV) and tomato leaf curl Palampur virus (ToLCPMV) are limiting factors for cucurbit production in south and southeastern Iran. ToLCPMV infects all cucurbit crops (except watermelons) whereas WmCSV is somewhat limited to watermelon, causing detrimental effects on fruit production. In a survey, we detected WmCSV in all watermelon growing farms in Fars province (southern Iran). Given that WmCSV and ToLCPMV are present in the same geographical location in Iran, we studied the interaction of two viruses. Co-infection using agroinfectious clones of WmCSV and ToLCPMV caused severe symptoms in watermelon and zucchini in comparison to symptoms observed from individual infections. Interestingly, inoculation of zucchini with WmCSV DNA-A and ToLCPMV DNA-B agroinfectious clones or vice versa produced a viable pseudo-recombinant and induced systemic symptoms. This demonstrates that replication-associated protein of DNA-A of each virus is able to bind to cis elements of the DNA-B molecules of another virus.

  17. Natural Occurrence of Tomato leaf curl New Delhi virus in Iranian Cucurbit Crops

    PubMed Central

    Yazdani-Khameneh, Sara; Aboutorabi, Samaneh; Shoori, Majid; Aghazadeh, Azin; Jahanshahi, Parastoo; Golnaraghi, Alireza; Maleki, Mojdeh

    2016-01-01

    The main areas for field-grown vegetable production in Iran were surveyed during the years of 2012–2014 to determine the occurrence of begomoviruses infecting these crops. A total of 787 leaf samples were collected from vegetables and some other host plants showing virus-like symptoms and tested by an enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies produced against Tomato yellow leaf curl virus (TYLCV). According to the ELISA results, 81 samples (10.3%) positively reacted with the virus antibodies. Begomovirus infections were confirmed by polymerase chain reaction (PCR) using previously described TYLCV-specific primer pair TYLCV-Sar/TYLCV-Isr or universal primer pair Begomo-F/Begomo-R. The PCR tests using the primer pair TYLCV-Sar/TYLCV-Isr resulted in the amplification of the expected fragments of ca. 0.67-kb in size for ELISA-positive samples tested from alfalfa, pepper, spinach and tomato plants, confirming the presence of TYLCV. For one melon sample, having a week reaction in ELISA and no reaction in PCR using TYLCV-specific primers, the PCR reaction using the primer pair Begomo-F/Begomo-R resulted in the amplification fragments of the expected size of ca. 2.8 kb. The nucleotide sequences of the DNA amplicons derived from the isolate, Kz-Me198, were determined and compared with other sequences available in GenBank. BLASTN analysis confirmed the begomovirus infection of the sample and showed 99% identities with Tomato leaf curl New Delhi virus (ToLCNDV); phylogenetic analysis supported the results of the database searches. This study reports the natural occurrence of TYLCV in different hosts in Iran. Our results also reveal the emergence of ToLCNDV in Iranian cucurbit crops. PMID:27298595

  18. Natural Occurrence of Tomato leaf curl New Delhi virus in Iranian Cucurbit Crops.

    PubMed

    Yazdani-Khameneh, Sara; Aboutorabi, Samaneh; Shoori, Majid; Aghazadeh, Azin; Jahanshahi, Parastoo; Golnaraghi, Alireza; Maleki, Mojdeh

    2016-06-01

    The main areas for field-grown vegetable production in Iran were surveyed during the years of 2012-2014 to determine the occurrence of begomoviruses infecting these crops. A total of 787 leaf samples were collected from vegetables and some other host plants showing virus-like symptoms and tested by an enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies produced against Tomato yellow leaf curl virus (TYLCV). According to the ELISA results, 81 samples (10.3%) positively reacted with the virus antibodies. Begomovirus infections were confirmed by polymerase chain reaction (PCR) using previously described TYLCV-specific primer pair TYLCV-Sar/TYLCV-Isr or universal primer pair Begomo-F/Begomo-R. The PCR tests using the primer pair TYLCV-Sar/TYLCV-Isr resulted in the amplification of the expected fragments of ca. 0.67-kb in size for ELISA-positive samples tested from alfalfa, pepper, spinach and tomato plants, confirming the presence of TYLCV. For one melon sample, having a week reaction in ELISA and no reaction in PCR using TYLCV-specific primers, the PCR reaction using the primer pair Begomo-F/Begomo-R resulted in the amplification fragments of the expected size of ca. 2.8 kb. The nucleotide sequences of the DNA amplicons derived from the isolate, Kz-Me198, were determined and compared with other sequences available in GenBank. BLASTN analysis confirmed the begomovirus infection of the sample and showed 99% identities with Tomato leaf curl New Delhi virus (ToLCNDV); phylogenetic analysis supported the results of the database searches. This study reports the natural occurrence of TYLCV in different hosts in Iran. Our results also reveal the emergence of ToLCNDV in Iranian cucurbit crops. PMID:27298595

  19. Strains of a new bipartite begomovirus, pepper yellow leaf curl Indonesia virus, in leaf-curl-diseased tomato and yellow-vein-diseased ageratum in Indonesia.

    PubMed

    Sakata, Jyun-Ji; Shibuya, Yutaka; Sharma, Pradeep; Ikegami, Masato

    2008-01-01

    The complete nucleotide sequences of begomoviruses from pepper with leaf curl and yellowing symptoms, tomato with leaf curl symptoms, and ageratum with yellow vein in Indonesia were determined. On the basis of genome organization and sequence homology, they were proposed to belong to a new species, Pepper yellow leaf curl Indonesia virus (PepYLCIV), which includes the new strains PepYLCIV-Tomato and PepYLCIV-Ageratum. These viruses had bipartite genomes. Pepper virus DNAs from Indonesia (PepYLCIV, PepYLCIV-Tomato and PepYLCIV-Ageratum DNA-As) were noticeably distinct, forming a separate branch from the viruses infecting pepper. Considerable divergence was observed in the common region (CR) of the genomic components of PepYLCIV (77%), PepYLCIV-Tomato (82%) and PeYLCIV-Ageratum (75%). A stem-loop-forming region and a Rep-binding motif were identical in the CR of the three viruses. The CRs of PepYLCIV-Ageratum DNA-A was approximately 10 nucleotides longer than that of PepYLCIV DNA-A and PepYLCIV-Tomato DNA-A. A similar insertion was also found in the CR of PepYLCIV-Ageratum DNA-B. PepYLCIV DNA-A alone was infectious in pepper and Nicotiana benthamiana plants, and association with DNA-B increased symptom severity.

  20. Transgenic tomato plants expressing the tomato yellow leaf curl virus capsid protein are resistant to the virus.

    PubMed

    Kunik, T; Salomon, R; Zamir, D; Navot, N; Zeidan, M; Michelson, I; Gafni, Y; Czosnek, H

    1994-05-01

    The tomato yellow leaf curl virus (TYLCV) gene that encodes the capsid protein (V1) was placed under transcriptional control of the cauliflower mosaic virus 35S promoter and cloned into an Agrobacterium Ti-derived plasmid and used to transform plants from an interspecific tomato hybrid, Lycopersicon esculentum X L. pennellii (F1), sensitive to the TYLCV disease. When transgenic F1 plants, expressing the V1 gene, were inoculated with TYLCV using whiteflies fed on TYLCV-infected plants, they responded either as untransformed tomato or showed expression of delayed disease symptoms and recovery from the disease with increasingly more resistance upon repeated inoculation. Transformed plants that were as sensitive to inoculation as untransformed controls expressed the V1 gene at the RNA level only. All the transformed plants that recovered from disease expressed the TYLCV capsid protein. PMID:7764709

  1. Multiple forms of vector manipulation by a plant-infecting virus: Bemisia tabaci and tomato yellow leaf curl virus.

    PubMed

    Liu, Baiming; Preisser, Evan L; Chu, Dong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

    2013-05-01

    For many insect-vectored plant viruses, the relationship between feeding behavior and vector competence may prove integral to an understanding of the epidemiology of the resulting plant disease. While plant-infecting viruses are well known to change host plant physiology in a way that makes them more attractive to vectors, viral manipulation of the vectors themselves has only recently been reported. Previous research suggested that the rapid spread of Tomato yellow leaf curl virus (TYLCV) throughout China has been facilitated by its primary vector, the whitefly Bemisia tabaci. We conducted two experiments testing the impact of TYLCV infection of the host plant (tomato) and vector (B. tabaci biotypes B and Q) on whitefly feeding behavior. Whiteflies of biotypes B and Q both appeared to find TYLCV-infected plants more attractive, probing them more quickly and having a greater number of feeding bouts; this did not, however, alter the total time spent feeding. Viruliferous whiteflies fed more readily than uninfected whiteflies and spent more time salivating into sieve tube elements. Because vector salivation is essential for viral transmission, this virally mediated alteration of behavior should provide TYLCV a direct fitness benefit. This is the first report of such manipulation by a nonpropagative virus that belongs to an exclusively plant-infecting family of viruses (Geminiviridae). In the context of previous research showing that feeding on TYLCV-infected plants harms biotype B but helps biotype Q, the fact that both biotypes were equally affected by TYLCV also suggests that the virus may alter the biotype B-biotype Q competitive interaction in favor of biotype Q. PMID:23408638

  2. First record of tomato yellow leaf curl Sardinia virus (TYLCSV) on pepper in Italy.

    PubMed

    Fanigliulo, A; Pacella, R; Comes, S; Crescenzi, A

    2008-01-01

    During a survey in summer 2007, a disease of pepper (Capsicum annuum) under plastic tunnels was observed in Policoro (Matera), on the Ionic coast of Basilicata Region, with a disease incidence in some cases of more than 50%. Affected cultivars were Eppo and Almund (S Et G). The diseased plants exhibited light mosaic or mottling, leaf distortion, interveinal and marginal leaf chlorosis, upward curling of leaf margins of older leaves. The causal pathogen was suspected to be a begomovirus due to the large population of the whitefly Bemisia tabaci observed on the crop. Detection assays for Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV) were used. In DAS-ELISA, positive results (178 plants resulted positive over 200 symptomatic plants assayed) were obtained using a "broad-spectrum" reagent combination (distributed by Bioreba AG) detecting TYLCV, TYLCSV, and other begamoviruses. A couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene of TYLCSV and TYLCV was used for PCR of ELISA positive samples in order to perform the molecular characterisation of the viral isolate responsible of the disease. RFLP analysis performed on the PCR product, 1008 bp long, showed the presence of only TYLCSV in the infected pepper plants. The same couple of primers allowed the detection of the virus also in symptomless pepper plants. To test whitefly transmission, adults of B. tabaci allowed to feed on naturally infected pepper plants were transferred on 10 healthy Eppo pepper seedlings (15 whiteflies/plant). Insects were killed 2 days later using an insecticide. Twenty days post exposition 10 plants/10 resulted positive in ELISA, and showed the same symptoms observed in natural infection. TYLCSV was not reported before on pepper in the surveyed area, but it was recorded with severe outbreaks on tomato, both in protected and in open field crops. This species was probably the primary source of infection from

  3. The autophagy pathway participates in resistance to tomato yellow leaf curl virus infection in whiteflies.

    PubMed

    Wang, Lan-Lan; Wang, Xin-Ru; Wei, Xue-Mei; Huang, Huang; Wu, Jian-Xiang; Chen, Xue-Xin; Liu, Shu-Sheng; Wang, Xiao-Wei

    2016-09-01

    Macroautophagy/autophagy plays an important role against pathogen infection in mammals and plants. However, little has been known about the role of autophagy in the interactions of insect vectors with the plant viruses, which they transmit. Begomoviruses are a group of single-stranded DNA viruses and are exclusively transmitted by the whitefly Bemisia tabaci in a circulative manner. In this study, we found that the infection of a begomovirus, tomato yellow leaf curl virus (TYLCV) could activate the autophagy pathway in the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex as evidenced by the formation of autophagosomes and ATG8-II. Interestingly, the activation of autophagy led to the subsequent degradation of TYLCV coat protein (CP) and genomic DNA. While feeding the whitefly with 2 autophagy inhibitors (3-methyladenine and bafilomycin A1) and silencing the expression of Atg3 and Atg9 increased the viral load; autophagy activation via feeding of rapamycin notably decreased the amount of viral CP and DNA in the whitefly. Furthermore, we found that activation of whitefly autophagy could inhibit the efficiency of virus transmission; whereas inhibiting autophagy facilitated virus transmission. Taken together, these results indicate that TYLCV infection can activate the whitefly autophagy pathway, which leads to the subsequent degradation of virus. Furthermore, our report proves that an insect vector uses autophagy as an intrinsic antiviral program to repress the infection of a circulative-transmitted plant virus. Our data also demonstrate that TYLCV may replicate and trigger complex interactions with the insect vector. PMID:27310765

  4. Characterization of a synergistic interaction between two cucurbit-infecting begomoviruses: Squash leaf curl virus and Watermelon chlorotic stunt virus.

    PubMed

    Sufrin-Ringwald, Tali; Lapidot, Moshe

    2011-02-01

    Squash leaf curl virus (SLCV) and Watermelon chlorotic stunt virus (WmCSV) are cucurbit-infecting bipartite begomoviruses. Both viruses are found in the eastern Mediterranean basin but the effects of dual infection of both viruses on melon (Cucumis melo L.) have not been described. 'Arava' melon plants were inoculated in the greenhouse, using whiteflies, with either SLCV, WmCSV, or both. Control plants were exposed to nonviruliferous whiteflies or not exposed at all. Following inoculation, plants were transplanted to a 50-mesh insect-proof nethouse and grown until fruit maturity. The experiment was performed in two melon-growing seasons: spring, transplant in May and harvest in July; and summer, transplant in August and harvest in October. Following inoculation, SLCV-infected melon plants showed mild symptoms that disappeared with time, and there was no effect on plant height. WmCSV-infected plants developed disease symptoms that became more obvious with time, and plants were somewhat shorter than control plants in the spring but not in the summer. SLCV had no effect on yield, regardless of season. WmCSV had no statistically significant effect on yield in the spring but, in the summer, reduced yield by 22%, on average. Dual-inoculated plants showed a synergistic interaction between the two viruses. They developed disease symptoms that were more pronounced than WmCSV alone, with plants being shorter than control plants by 20 to 25% regardless of season. Moreover, the yield of dual-inoculated plants was reduced on average by 21% in the spring and 54% in the summer, and fruit appearance was adversely affected. Dual inoculation did not affect WmCSV DNA level but SLCV DNA level was increased several-fold by the presence of WmCSV.

  5. RNA viruses and their silencing suppressors boost Abutilon mosaic virus, but not the Old World Tomato yellow leaf curl Sardinia virus.

    PubMed

    Sardo, Luca; Wege, Christina; Kober, Sigrid; Kocher, Conny; Accotto, Gian Paolo; Noris, Emanuela

    2011-11-01

    Mixed viral infections can induce different changes in symptom development, genome accumulation and tissue tropism. These issues were investigated for two phloem-limited begomoviruses, Abutilon mosaic virus (AbMV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) in Nicotiana benthamiana plants doubly infected by either the potyvirus Cowpea aphid-borne mosaic virus (CABMV) or the tombusvirus Artichoke mottled crinkle virus (AMCV). Both RNA viruses induced an increase of the amount of AbMV, led to its occasional egress from the phloem and induced symptom aggravation, while the amount and tissue tropism of TYLCSV were almost unaffected. In transgenic plants expressing the silencing suppressors of CABMV (HC-Pro) or AMCV (P19), AbMV was supported to a much lesser extent than in the mixed infections, with the effect of CABMV HC-Pro being superior to that of AMCV P19. Neither of the silencing suppressors influenced TYLCSV accumulation. These results demonstrate that begomoviruses differentially respond to the invasion of other viruses and to silencing suppression. PMID:21843560

  6. Pathogenicity and insect transmission of a begomovirus complex between tomato yellow leaf curl virus and Ageratum yellow vein betasatellite.

    PubMed

    Ueda, Shigenori; Onuki, Masatoshi; Yamashita, Masataka; Yamato, Yoichi

    2012-04-01

    Tomato yellow leaf curl virus (TYLCV) and Ageratum yellow vein betasatellite (AYVB) are members of the genus Begomovirus (family Geminiviridae). TYLCV and AYVB have been found in Japan over the last 15 years, and are associated with tomato leaf curl and the tomato yellow leaf curl diseases (TYLCD). AYVB is also associated with some monopartite begomoviruses. We have cloned both TYLCV and AYVB and demonstrated that TYLCV can trans-replicate with AYVB in Nicotiana benthamiana and tomato plants. A mixed infection of TYLCV and AYVB induced more severe symptoms of upward leaf curl, stunting, vein thickening, and swelling compared with TYLCV infection alone. The symptoms induced by infection of AYVB included a rise in abnormal cell proliferation, and pigmentation around leaf vein tissues. This is the first study to show that a complex of TYLCV and AYVB can be transmitted by vector insects among tomato plants. These results indicate that TYLCV possesses the potential to induce severe TYLCD by associating with AYVB.

  7. Rapid fluorescent reporter quantification by leaf disc analysis and its application in plant-virus studies

    PubMed Central

    2014-01-01

    Background Fluorescent proteins are extraordinary tools for biology studies due to their versatility; they are used extensively to improve comprehension of plant-microbe interactions. The viral infection process can easily be tracked and imaged in a plant with fluorescent protein-tagged viruses. In plants, fluorescent protein genes are among the most commonly used reporters in transient RNA silencing and heterologous protein expression assays. Fluorescence intensity is used to quantify fluorescent protein accumulation by image analysis or spectroscopy of protein extracts; however, these methods might not be suitable for medium- to large-scale comparisons. Results We report that laser scanners, used routinely in proteomic studies, are suitable for quantitative imaging of plant leaves that express different fluorescent protein pairs. We developed a microtiter plate fluorescence spectroscopy method for direct quantitative comparison of fluorescent protein accumulation in intact leaf discs. We used this technique to measure a fluorescent reporter in a transient RNA silencing suppression assay, and also to monitor early amplification dynamics of a fluorescent protein-labeled potyvirus. Conclusions Laser scanners allow dual-color fluorescence imaging of leaf samples, which might not be acquired in standard stereomicroscope devices. Fluorescence microtiter plate analysis of intact leaf discs can be used for rapid, accurate quantitative comparison of fluorescent protein accumulation. PMID:25053970

  8. Use of Tomato leaf curl virus (TYLCV) truncated Rep gene sequence to engineer TYLCV resistance in tomato plants.

    PubMed

    Ben Tamarzizt, H; Gharsallah Chouchane, S; Lengliz, R; Maxwell, D P; Marrakchi, M; Fakhfakh, H; Gorsane, F

    2009-01-01

    Tomato yellow leaf curl disease causes severe losses in tomato production throughout Mediterranean countries including Tunisia. In order to generate engineered resistance to this disease, an intron-hairpin RNA construct harboring a Tomato yellow leaf curl Sardinia virus (TYLCSV) truncated replication-associated protein (Rep) gene was used to transform genotype of tomato plants. Prepared transgenic plants were agro-inoculated with Tunisian infectious strain of TYLCSV and screened for the resistance to infection. The infected transgenic plants were divided into 3 different groups according to their specific symptoms. Only one of them contained transgenic plants fully resistant to the tomato yellow leaf curl disease. PMID:19537910

  9. Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus.

    PubMed

    Edelbaum, Dagan; Gorovits, Rena; Sasaki, Sonoko; Ikegami, Masato; Czosnek, Henryk

    2009-01-01

    Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus. PMID:19184338

  10. Evaluation of two gene-silencing constructs for resistance to tomato yellow leaf curl viruses in Nicotiana benthamiana plants.

    PubMed

    Gharsallah Chouchane, S; Gorsane, F; Nakhla, M K; Salus, M; Martin, C T; Maxwell, D P; Marrakchi, M; Fakhfakh, H

    2008-01-01

    Infiltration of Agrobacterium tumefaciens into intact plant leaves of N. benthamiana was used to test the efficiency of two virus-based silencing constructs conferring resistance to the closely related begomoviruses. The constructs contained the most conserved sequences of the coat protein (CP) gene and replication-associated protein (Rep) gene of Tomato yellow leaf curl Sardinia virus (Sicily strain) (TYLCSV-[Sic]). Both constructs formed a hairpin structure that enhanced the post-transcriptional gene-silencing mechanism. When agro-infiltrated plants were challenged separately with infectious viruses TYLCSV-[Sic] and Tomato yellow leaf curl virus (TYLCV), the plants showed resistance to TYLCSV-[Sic], but not to the related TYLCV. PMID:18999888

  11. Association of an alphasatellite with tomato yellow leaf curl virus and ageratum yellow vein virus in Japan is suggestive of a recent introduction.

    PubMed

    Shahid, Muhammad Shafiq; Ikegami, Masato; Waheed, Abdul; Briddon, Rob W; Natsuaki, Keiko T

    2014-01-01

    Samples were collected in 2011 from tomato plants exhibiting typical tomato leaf curl disease symptoms in the vicinity of Komae, Japan. PCR mediated amplification, cloning and sequencing of all begomovirus components from two plants from different fields showed the plants to be infected by Tomato yellow leaf curl virus (TYLCV) and Ageratum yellow vein virus (AYVV). Both viruses have previously been shown to be present in Japan, although this is the first identification of AYVV on mainland Japan; the virus previously having been shown to be present on the Okinawa Islands. The plant harboring AYVV was also shown to contain the betasatellite Tomato leaf curl Java betasatellite (ToLCJaB), a satellite not previously shown to be present in Japan. No betasatellite was associated with the TYLCV infected tomato plants analyzed here, consistent with earlier findings for this virus in Japan. Surprisingly both plants were also found to harbor an alphasatellite; no alphasatellites having previously been reported from Japan. The alphasatellite associated with both viruses was shown to be Sida yellow vein China alphasatellite which has previously only been identified in the Yunnan Province of China and Nepal. The results suggest that further begomoviruses, and their associated satellites, are being introduced to Japan. The significance of these findings is discussed. PMID:24424499

  12. Identification of differentially expressed genes in tomato associated with R-lines Ty-5 against tomato yellow leaf curl virus (TYLCV) and Sw-7 against tomato spotted wilt virus (TSWV)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato yellow leaf curl virus (TYLCV) and tomato spotted wilt virus (TSWV) are two most economically important viruses affecting tomato productions worldwide. Developing a cultivar with resistance to these viruses would be the most effective and economical means of disease management. Comparative ...

  13. Tomato yellow leaf curl virus (TYLCV-IL): a seed-transmissible geminivirus in tomatoes

    PubMed Central

    Kil, Eui-Joon; Kim, Sunhoo; Lee, Ye-Ji; Byun, Hee-Seong; Park, Jungho; Seo, Haneul; Kim, Chang-Seok; Shim, Jae-Kyoung; Lee, Jung-Hwan; Kim, Ji-Kwang; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Lee, Sukchan

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is one of the most well-known tomato-infecting begomoviruses and transmitted by Bemisia tabaci. Seed transmission has previously been reported for some RNA viruses, but TYLCV has not previously been described as a seed-borne virus. In 2013 and 2014, without whitefly-mediated transmission, TYLCV was detected in young tomato plants germinated from fallen fruits produced from TYLCV-infected tomato plants in the previous cultivation season. In addition, TYLCV-Israel (TYLCV-IL) was also detected in seeds and their seedlings of TYLCV-infected tomato plants that were infected by both viruliferous whitefly-mediated transmission and agro-inoculation. The seed infectivity was 20–100%, respectively, and the average transmission rate to seedlings was also 84.62% and 80.77%, respectively. TYLCV-tolerant tomatoes also produced TYLCV-infected seeds, but the amount of viral genome was less than seen in TYLCV-susceptible tomato plants. When tomato plants germinated from TYLCV-infected seeds, non-viruliferous whiteflies and healthy tomato plants were placed in an insect cage together, TYLCV was detected from whiteflies as well as receiver tomato plants six weeks later. Taken together, TYLCV-IL can be transmitted via seeds, and tomato plants germinated from TYLCV-infected seeds can be an inoculum source of TYLCV. This is the first report about TYLCV seed transmission in tomato. PMID:26743765

  14. Inhibition of Tomato Yellow Leaf Curl Virus (TYLCV) using whey proteins

    PubMed Central

    2010-01-01

    The antiviral activity of native and esterified whey proteins fractions (α-lactalbumin, β-lactoglobulin, and lactoferrin) was studied to inhibit tomato yellow leaf curl virus (TYLCV) on infected tomato plants. Whey proteins fractions and their esterified derivatives were sprayed into TYLCV-infected plants. Samples were collected from infected leaves before treatment, 7 and 15 days after treatment for DNA and molecular hybridization analysis. The most evident inhibition of virus replication was observed after 7 and 15 days using α-lactoferrin and α-lactalbumin, respectively. Native and esterified lactoferrin showed complete inhibition after 7 days. On the other hand, native β-lactoglobulin showed inhibition after 7 and 15 days whereas esterified β-lactoglobulin was comparatively more effective after 7 days. The relative amount of viral DNA was less affected by the esterified α-lactalbumin whereas native α-lactalbumin inhibited virus replication completely after 15 days. These results indicate that native or modified whey proteins fractions can be used for controlling the TYLCV-infected plants. PMID:20128897

  15. Tomato Breeding Lines Resistant and Tolerant to Tomato Yellow Leaf Curl Virus Issued from Lycopersicon hirsutum.

    PubMed

    Vidavsky, F; Czosnek, H

    1998-09-01

    ABSTRACT Two tomato yellow leaf curl virus (TYLCV)-resistant plants from accessions LA1777 and LA386 of the wild tomato species Lycopersicon hirsutum have been crossed. The resulting resistant F1 plants were crossed with the domesticated tomato L. esculentum, and a series of selfing was performed. At each generation, individuals were selected for resistance (no symptoms and undetectable viral DNA) and tolerance (no symptoms but with detectable viral DNA) following controlled massive and repeated inoculations with viruliferous whiteflies. A stable BC1F4 line (denominated 902) that does not segregate for resistance was obtained. This line does not support virus accumulation, even upon extensive whitefly-mediated inoculation of young seedlings, and does not need protection with nets or insecticides. Another stable BC1F4 line (denominated 908) was tolerant to the virus. Both lines have good horticultural characteristics and bear 80- to 120-g red fruits. Analysis of segregation of susceptibility, tolerance, and resistance during the BC1F1 to BC1F4 crosses indicated that tolerance is controlled by a dominant major gene and resistance by two to three additive recessive genes. The resistant and tolerant lines do not need to be protected by insecticides or nets. PMID:18944868

  16. Recombinant-antibody-mediated resistance against Tomato yellow leaf curl virus in Nicotiana benthamiana.

    PubMed

    Safarnejad, Mohammad Reza; Fischer, Rainer; Commandeur, Ulrich

    2009-01-01

    Tomato yellow leaf curl virus (TYLCV) is a geminivirus species whose members cause severe crop losses in the tropics and subtropics. We report the expression of a single-chain variable fragment (scFv) antibody that protected Nicotiana benthamiana plants from a prevalent Iranian isolate of the virus (TYLCV-Ir). Two recombinant antibodies (scFv-ScRep1 and scFv-ScRep2) interacting with the multifunctional replication initiator protein (Rep) were obtained from phage display libraries and expressed in plants, both as stand-alone proteins and as N-terminal GFP fusions. Initial results indicated that both scFvs and both fusions accumulated to a detectable level in the cytosol and nucleus of plant cells. Transgenic plants challenged with TYLCV-Ir showed that the scFv-ScRep1, but more so the fusion proteins, were able to suppress TYLCV-Ir replication. These results show that expression of a scFv-ScRep1-GFP fusion protein can attenuate viral DNA replication and prevent the development of disease symptoms. The present article describes the first successful application of a recombinant antibody-mediated resistance approach against a plant DNA virus. PMID:19234665

  17. Tomato yellow leaf curl virus (TYLCV-IL): a seed-transmissible geminivirus in tomatoes.

    PubMed

    Kil, Eui-Joon; Kim, Sunhoo; Lee, Ye-Ji; Byun, Hee-Seong; Park, Jungho; Seo, Haneul; Kim, Chang-Seok; Shim, Jae-Kyoung; Lee, Jung-Hwan; Kim, Ji-Kwang; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Lee, Sukchan

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is one of the most well-known tomato-infecting begomoviruses and transmitted by Bemisia tabaci. Seed transmission has previously been reported for some RNA viruses, but TYLCV has not previously been described as a seed-borne virus. In 2013 and 2014, without whitefly-mediated transmission, TYLCV was detected in young tomato plants germinated from fallen fruits produced from TYLCV-infected tomato plants in the previous cultivation season. In addition, TYLCV-Israel (TYLCV-IL) was also detected in seeds and their seedlings of TYLCV-infected tomato plants that were infected by both viruliferous whitefly-mediated transmission and agro-inoculation. The seed infectivity was 20-100%, respectively, and the average transmission rate to seedlings was also 84.62% and 80.77%, respectively. TYLCV-tolerant tomatoes also produced TYLCV-infected seeds, but the amount of viral genome was less than seen in TYLCV-susceptible tomato plants. When tomato plants germinated from TYLCV-infected seeds, non-viruliferous whiteflies and healthy tomato plants were placed in an insect cage together, TYLCV was detected from whiteflies as well as receiver tomato plants six weeks later. Taken together, TYLCV-IL can be transmitted via seeds, and tomato plants germinated from TYLCV-infected seeds can be an inoculum source of TYLCV. This is the first report about TYLCV seed transmission in tomato. PMID:26743765

  18. Female-biased symbionts and tomato yellow leaf curl virus infections in Bemisia tabaci.

    PubMed

    Guo, Huifang; Qu, Yufeng; Liu, Xiangdong; Zhong, Wanfang; Fang, Jichao

    2014-01-01

    The female-biased infection of facultative symbionts has been found in Bemisia tabaci; however, whether there are any differences in tomato yellow leaf curl virus (TYLCV) and obligate symbiont infection rates between females and males is unknown. Determining whether such differences exist would be very important for understanding the spread of the plant virus and of the symbionts. We compared both symbiont infection types, including obligate and facultative symbionts, and the rates of TYLCV infection in both sexes in five field populations from Jiangsu Province, China. The obligate symbiont Portiera aleyrodidarum was not found in every whitefly tested. In all tested populations, more females than males were found to harbor P. aleyrodidarum; and more females than males also harbored Hamiltonella defense, the most common facultative symbiont as well as Cardinium. In addition to female-biased symbiont infections, there were also female-biased TYLCV infections, and the infection frequencies of this plant virus in females were higher than those in males. Taken together, these results suggested that both the female-biased symbiont infections and female-biased TYLCV infections promoted the rapid spread of TYLCV in China. PMID:24465416

  19. The relationship between Pepper mottle virus source leaf and spread of infection through the stem of Capsicum sp.

    PubMed

    Murphy, J F

    2002-09-01

    Pepper mottle virus (PepMoV) systemically infects Capsicum sp. in a typical source-to-sink manner with movement through the stem occurring in a predictable pattern. This study was carried out to determine the relationship between the inoculated leaf as a source of inoculum and the spread of PepMoV infection through the stem. C. annuum 'Early Calwonder' plants were mechanically inoculated onto the first leaf with PepMoV and sets of 30 plants had their inoculated leaves removed each day from 1 through 7 days post-inoculation (dpi) with the inoculated leaves tested for infection by ELISA at the time of excision. Beginning at 2 dpi, PepMoV infection in the stem of plants with the inoculated leaf excised and plants of a nonexcision control treatment was determined using immuno-tissue blot analysis. PepMoV was detected in inoculated leaves beginning at 3 dpi with the percentage of infected leaves increasing each day through 7 dpi. PepMoV was first detected in the stem of inoculated plants of the 3 dpi excision treatment. The accumulation and extent of spread of infection in the stem was similar for plants that had their inoculated leaf removed at a time preceding detection by ELISA to plants in the nonexcision control treatment. These findings suggest that once virus is allowed to enter the stem from the inoculated leaf, subsequent spread of infection through the stem is a process independent from the source leaf.

  20. Implications Of Host Plant Resistance Against Whitefly-Transmitted Tomato Yellow Leaf Curl Virus In Tomato For Virus Epidemics And Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whitefly-transmitted Tomato yellow leaf curl virus (TYLCV) severely impacts tomato production in southeastern USA. Growers typically spray insecticides against whiteflies and plant TYLCV-resistant genotypes. Semi-dominant genes such as TY-1 and TY-2 confer resistance to TYLCV. Resistant genotypes ar...

  1. Upregulation of temperature susceptibility in Bemisia tabaci upon acquisition of Tomato yellow leaf curl virus (TYLCV).

    PubMed

    Pusag, Joseph Carlo A; Hemayet Jahan, S M; Lee, Kwan-Suk; Lee, Sukchan; Lee, Kyeong-Yeoll

    2012-10-01

    Acquisition of plant viruses has various effects on physiological mechanisms in vector insects. Bemisia tabaci is the only known vector of Tomato yellow leaf curl virus (TYLCV), which is a serious virus affecting tomato cultivars. In this study, the lifespan of Q1 biotype was compared between non-viruliferous (NV) and TYLCV-viruliferous (V) whiteflies. Total lifespan from egg to adult death of NV whiteflies was 62.54 days but 10.64 days shorter in V whiteflies. We investigated the temperature susceptibility of B. tabaci by comparing mortalities as well as heat shock protein (hsp) mRNA levels between NV and V whiteflies. For this, NV and V whiteflies were exposed for either 1 or 3h at 4, 25, and 35°C. The mortality of V whiteflies was higher than NV ones following exposure at either 4 or 35°C, but there was no significant difference at 25°C. Analysis of the expression level of heat shock protein (hsp) genes using quantitative real-time PCR showed that both cold and heat shock treatments stimulated higher expression of hsps (hsp40, hsp70, and hsp90) at various rates in V whiteflies than NV ones, but there was no difference at 25°C. All together, our results show that TYLCV acquisition accelerated the developmental rate and increased susceptibility to thermal stress in B. tabaci. Therefore, this modification may result in reduced vector longevity due to increased metabolic energy utilization. Our results provide insights into the complex interaction between vector fitness and thermal stress in relation to the acquisition and transmission of plant viruses. PMID:22841829

  2. Mathematical modeling of cotton leaf curl virus with respect to environmental factors.

    PubMed

    Khan, Jahangir; Bashir, Zoobia; Ahmad, Aqeel; Tariq, Wajeeha; Yousaf, Anam; Gohar, Madiha

    2015-06-01

    This study mathematically correlates incidence of cotton leaf curl virus (CLCuV), environmental factors (i.e., rainfall, humidity and temperature), and silverleaf whitefly population in agricultural system of Pakistan. It has been concluded that the disease is directly linked with rainfall and humidity. The third most influential factor in defining CLCuV incidence is the vector population, which is also strictly dependent upon monthly mean temperature of Pakistan. Developed mathematical interrelation is capable of predicting disease incidence of future months. Therefore, it will help agriculturists to control disease in agricultural areas of Pakistan. It is strongly advised on the basis of current research that vector population controlling practices should be immediately applied after detecting small elevations in mean monthly temperature.

  3. Mathematical modeling of cotton leaf curl virus with respect to environmental factors

    PubMed Central

    Khan, Jahangir; Bashir, Zoobia; Ahmad, Aqeel; Tariq, Wajeeha; Yousaf, Anam; Gohar, Madiha

    2015-01-01

    This study mathematically correlates incidence of cotton leaf curl virus (CLCuV), environmental factors (i.e., rainfall, humidity and temperature), and silverleaf whitefly population in agricultural system of Pakistan. It has been concluded that the disease is directly linked with rainfall and humidity. The third most influential factor in defining CLCuV incidence is the vector population, which is also strictly dependent upon monthly mean temperature of Pakistan. Developed mathematical interrelation is capable of predicting disease incidence of future months. Therefore, it will help agriculturists to control disease in agricultural areas of Pakistan. It is strongly advised on the basis of current research that vector population controlling practices should be immediately applied after detecting small elevations in mean monthly temperature. PMID:26185686

  4. Engineering resistance against tomato yellow leaf curl virus (TYLCV) using antisense RNA.

    PubMed

    Bendahmane, M; Gronenborn, B

    1997-01-01

    One of the most severe diseases of cultivated tomato worldwide is caused by tomato yellow leaf curl virus (TYLCV), a geminivirus transmitted by the whitefly Bemisia tabaci. Here we describe the application of antisense RNAs to interfere with the disease caused by TYLCV. The target of the antisense RNA is the rare messenger RNA of the Rep protein, encoded by the C1 gene. Transgenic Nicotiana benthamiana plants expressing C1 antisense RNA were obtained and shown to resist infection by TYLCV. Some of the resistant lines are symptomless, and the replication of challenge TYLCV almost completely suppressed. The transgenes mediating resistance were shown to be effective through at least two generations of progeny. PMID:9037152

  5. Tomato yellow leaf curl virus confronts host degradation by sheltering in small/midsized protein aggregates.

    PubMed

    Gorovits, Rena; Fridman, Lilia; Kolot, Mikhail; Rotem, Or; Ghanim, Murad; Shriki, Oz; Czosnek, Henryk

    2016-02-01

    Tomato yellow leaf curl virus (TYLCV) is a begomovirus transmitted by the whitefly Bemisia tabaci to tomato and other crops. TYLCV proteins are endangered by the host defenses. We have analyzed the capacity of the tomato plant and of the whitefly insect vector to degrade the six proteins encoded by the TYLCV genome. Tomato and whitefly demonstrated the highest proteolytic activity in the fractions containing soluble proteins, less-in large protein aggregates; a significant decrease of TYLCV proteolysis was detected in the intermediate-sized aggregates. All the six TYLCV proteins were differently targeted by the cytoplasmic and nuclear degradation machineries (proteases, ubiquitin 26S proteasome, autophagy). TYLCV could confront host degradation by sheltering in small/midsized aggregates, where viral proteins are less exposed to proteolysis. Indeed, TYLCV proteins were localized in aggregates of various sizes in both host organisms. This is the first study comparing degradation machinery in plant and insect hosts targeting all TYLCV proteins. PMID:26654789

  6. Squash leaf curl virus (SLCV): a serious disease threatening cucurbits production in Palestine.

    PubMed

    Ali-Shtayeh, M S; Jamous, R M; Hussein, E Y; Mallah, O B; Abu-Zeitoun, S Y

    2014-04-01

    The incidence of squash leaf curl disease and molecular characterization of the Palestinian isolate of Squash leaf curl virus [SLCV-(PAL)] are described in this study. Symptomatic leaf samples obtained from squash (Cucurbita pepo), watermelon [Citrullus lanatus (Thunb.)], and cucumber (Cucumis sativus L.) plants were tested for SLCV-[PAL] infection by PCR and RCA. SLCV was also found to occur naturally in Chenopodium murale, Convolvulus sp, and Prosporis farcta which showed yellowing. The disease incidence was 85 % in samples collected from Nablus in summer season, while it was 98 % in samples collected from Qalqilia in autumn. On the other hand, SLCV incidence did not exceed 25 % in winter season. The full-length DNA-A and DNA-B genomes of SLCV-[PAL] were amplified and sequenced, and the sequences were deposited in the GenBank. Sequence analysis reveals that SLCV-[PAL] is closely related to other isolates from Lebanon (SLCV-LB2), Jordan (SLCV-JO), Israel (SLCV-IL), and Egypt (SLCV-EG). DNA-A of SLCV-[PAL] showed the highest nucleotide identity (99.4 %) with SLCV-JO, and SLCV-LB2, while DNA-B had the highest nucleotide identity (99.3 %) with SLCV-IL. However, following genome sequencing, it was found that due to two separate point mutations, two viral open reading frames (ORF) were altered in some SLCV Palestinian isolates. The AC2 ORF was extended by 141 nucleotides, while the AC4 ORF was extended by 36 nucleotides.

  7. Raspberry leaf blotch virus, a putative new member of the genus Emaravirus, encodes a novel genomic RNA.

    PubMed

    McGavin, Wendy J; Mitchell, Carolyn; Cock, Peter J A; Wright, Kathryn M; MacFarlane, Stuart A

    2012-02-01

    A new, segmented, negative-strand RNA virus with morphological and sequence similarities to other viruses in the genus Emaravirus was discovered in raspberry plants exhibiting symptoms of leaf blotch disorder, a disease previously attributed to the eriophyid raspberry leaf and bud mite (Phyllocoptes gracilis). The virus, tentatively named raspberry leaf blotch virus (RLBV), has five RNAs that each potentially encode a single protein on the complementary strand. RNAs 1, 2 and 3 encode, respectively, a putative RNA-dependent RNA polymerase, a glycoprotein precursor and the nucleocapsid. RNA4 encodes a protein with sequence similarity to proteins of unknown function that are encoded by the genomes of other emaraviruses. When expressed transiently in plants fused to green or red fluorescent protein, the RLBV P4 protein localized to the peripheral cell membrane and to punctate spots in the cell wall. These spots co-localized with GFP-tagged tobacco mosaic virus 30K cell-to-cell movement protein, which is itself known to associate with plasmodesmata. These results suggest that the P4 protein may be a movement protein for RLBV. The fifth RLBV RNA, encoding the P5 protein, is unique among the sequenced emaraviruses. The amino acid sequence of the P5 protein does not suggest any potential function; however, when expressed as a GFP fusion, it localized as small aggregates in the cytoplasm near to the periphery of the cell.

  8. Within-host dynamics of the emergence of Tomato yellow leaf curl virus recombinants.

    PubMed

    Urbino, Cica; Gutiérrez, Serafin; Antolik, Anna; Bouazza, Nabila; Doumayrou, Juliette; Granier, Martine; Martin, Darren P; Peterschmitt, Michel

    2013-01-01

    Tomato yellow leaf curl virus (TYLCV) is a highly damaging begomovirus native to the Middle East. TYLCV has recently spread worldwide, recombining with other begomoviruses. Recent analysis of mixed infections between TYLCV and Tomato leaf curl Comoros begomovirus (ToLCKMV) has shown that, although natural selection preserves certain co-evolved intra-genomic interactions, numerous and diverse recombinants are produced at 120 days post-inoculation (dpi), and recombinant populations from different tomato plants are very divergent. Here, we investigate the population dynamics that lead to such patterns in tomato plants co-infected with TYLCV and ToLCKMV either by agro-inoculation or using the natural whitefly vector Bemisia tabaci. We monitored the frequency of parental and recombinant genotypes independently in 35 plants between 18 and 330 dpi and identified 177 recombinants isolated at different times. Recombinants were detected from 18 dpi and their frequency increased over time to reach about 50% at 150 dpi regardless of the inoculation method. The distribution of breakpoints detected on 96 fully sequenced recombinants was consistent with a continuous generation of new recombinants as well as random and deterministic effects in their maintenance. A severe population bottleneck of around 10 genomes was estimated during early systemic infection-a phenomenon that could account partially for the heterogeneity in recombinant patterns observed among plants. The detection of the same recombinant genome in six of the thirteen plants analysed beyond 30 dpi supported the influence of selection on observed recombination patterns. Moreover, a highly virulent recombinant genotype dominating virus populations within one plant has, apparently, the potential to be maintained in the natural population according to its infectivity, within-host accumulation, and transmission efficiency - all of which were similar or intermediate to those of the parent genotypes. Our results

  9. Lamium amplexicaule (Lamiaceae): a weed reservoir for tomato yellow leaf curl virus (TYLCV) in Korea.

    PubMed

    Kil, Eui-Joon; Park, Jungan; Lee, Hyejung; Kim, Jaedeok; Choi, Hong-Soo; Lee, Kyeong-Yeoll; Kim, Chang-Seok; Lee, Sukchan

    2014-06-01

    After the first identification of tomato yellow leaf curl virus (TYLCV) in the southern part of Korea in 2008, TYLCV has rapidly spread to tomato farms in most regions of Korea. From 2008 to 2010, a survey of natural weed hosts that could be reservoirs of TYLCV was performed in major tomato production areas of Korea. About 530 samples were collected and identified as belonging to 25 species from 11 families. PCR and Southern hybridization were used to detect TYLCV in samples, and replicating forms of TYLCV DNA were detected in three species (Achyranthes bidentata, Lamium amplexicaule, and Veronica persica) by Southern hybridization. TYLCV transmission mediated by Bemisia tabaci from TYLCV-infected tomato plants to L. amplexicaule was confirmed, and TYLCV-infected L. amplexicaule showed symptoms such as yellowing, stunting, and leaf curling. TYLCV from infected L. amplexicaule was also transmitted to healthy tomato and L. amplexicaule plants by B. tabaci. The rate of infection of L. amplexicaule by TYLCV was similar to that of tomato. This report is the first to show that L. amplexicaule is a reservoir weed host for TYLCV. PMID:24327090

  10. Genetic diversity, host range, and distribution of tomato yellow leaf curl virus in Iran.

    PubMed

    Shirazi, M; Mozafari, J; Rakhshandehroo, F; Shams-Bakhsh, M

    2014-01-01

    Tomato yellow leaf curl virus (TYLCV) is considered one of the most important tomato pathogens in tropical and subtropical regions including Iran. During the years 2007 to 2009, a total number of 510 symptomatic and asymptomatic vegetable, ornamental and weed samples were collected from fields and greenhouses in ten provinces of Iran. Symptoms included stunting, yellowing, leaf curl and flower senescence. PCR with specific primers showed TYLCV infection in 184 samples (36%) such as cucumber, pepper, tomato and several weeds from seven provinces. Based on the geographical origin, host range and symptoms, twenty three representative isolates were selected for phylogenetic analysis. An amplicon with a size about 608 base pair (bp) comprising partial sequence of the coat (CP) and movement protein (MP) coding regions of the viral genome was sequenced and compared with the corresponding selected sequences available in GenBank for Iran and worldwide. Phylogenetic analyses on the basis of the nucleotide sequences indicated two geographically separated clades. Isolates collected from Hormozgan, Khuzestan and Kerman provinces were grouped together with other Iranian isolates including TYLCV-Ir2, TYLCV-Kahnooj, and an isolate from Oman. It was also revealed that isolates collected from Boushehr, Fars, Tehran, and Isfahan placed close to the Iranian isolate TYLCV-Abadeh and isolates from Israel and Egypt. No correlation was found between the genetic variation and the host species, but selected Iranian isolates were grouped on the basis of the geographical origins. Results of this study indicated a high genetic diversity among Iranian TYLCV isolates. PMID:24957717

  11. Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus.

    PubMed

    Pereira-Carvalho, Rita C; Díaz-Pendón, Juan A; Fonseca, Maria Esther N; Boiteux, Leonardo S; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O

    2015-05-01

    The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

  12. Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus

    PubMed Central

    Pereira-Carvalho, Rita C.; Díaz-Pendón, Juan A.; Fonseca, Maria Esther N.; Boiteux, Leonardo S.; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O.

    2015-01-01

    The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

  13. Molecular phylogenetics and evolution of host plant use in the Neotropical rolled leaf 'hispine' beetle genus Cephaloleia (Chevrolat) (Chrysomelidae: Cassidinae).

    PubMed

    McKenna, Duane D; Farrell, Brian D

    2005-10-01

    Here, we report the results of a species level phylogenetic study of Cephaloleia beetles designed to clarify relationships and patterns of host plant taxon and tissue use among species. Our study is based on up to 2088bp of mtDNA sequence data. Maximum parsimony, maximum likelihood, and Bayesian methods of phylogenetic inference consistently recover a monophyletic Cephaloleia outside of a basal clade of primarily palm feeding species (the 'Arecaceae-feeding clade'), and C. irregularis. In all three analyses, the 'Arecaceae-feeding clade' includes Cephaloleia spp. with unusual morphological features, and a few species currently placed in other cassidine genera and tribes. All three analyses also recover a clade that includes all Zingiberales feeding Cephaloleia and most Cephaloleia species (the 'Zingiberales-feeding clade'). Two notable clades are found within the 'Zingiberales-feeding clade.' One is comprised of beetles that normally feed only on the young rolled leaves of plants in the families Heliconiaceae and Marantaceae (the 'Heliconiaceae & Marantaceae-feeding clade'). The other is comprised of relative host tissue generalist, primarily Zingiberales feeding species (the 'generalist-feeding clade'). A few species in the 'generalist-feeding clade' utilize Cyperaceae or Poaceae as hosts. Overall, relatively basal Cephaloleia (e.g., the 'Arecaceae clade') feed on relatively basal monocots (e.g., Cyclanthaceae and Arecaceae), and relatively derived Cephaloleia (e.g., the 'Zingiberales-feeding clade') feed on relatively derived monocots (mostly in the order Zingiberales). Zingiberales feeding and specialization on young rolled Zingiberales leaves have each apparently evolved just once in Cephaloleia. PMID:16054400

  14. Molecular phylogenetics and evolution of host plant use in the Neotropical rolled leaf 'hispine' beetle genus Cephaloleia (Chevrolat) (Chrysomelidae: Cassidinae).

    PubMed

    McKenna, Duane D; Farrell, Brian D

    2005-10-01

    Here, we report the results of a species level phylogenetic study of Cephaloleia beetles designed to clarify relationships and patterns of host plant taxon and tissue use among species. Our study is based on up to 2088bp of mtDNA sequence data. Maximum parsimony, maximum likelihood, and Bayesian methods of phylogenetic inference consistently recover a monophyletic Cephaloleia outside of a basal clade of primarily palm feeding species (the 'Arecaceae-feeding clade'), and C. irregularis. In all three analyses, the 'Arecaceae-feeding clade' includes Cephaloleia spp. with unusual morphological features, and a few species currently placed in other cassidine genera and tribes. All three analyses also recover a clade that includes all Zingiberales feeding Cephaloleia and most Cephaloleia species (the 'Zingiberales-feeding clade'). Two notable clades are found within the 'Zingiberales-feeding clade.' One is comprised of beetles that normally feed only on the young rolled leaves of plants in the families Heliconiaceae and Marantaceae (the 'Heliconiaceae & Marantaceae-feeding clade'). The other is comprised of relative host tissue generalist, primarily Zingiberales feeding species (the 'generalist-feeding clade'). A few species in the 'generalist-feeding clade' utilize Cyperaceae or Poaceae as hosts. Overall, relatively basal Cephaloleia (e.g., the 'Arecaceae clade') feed on relatively basal monocots (e.g., Cyclanthaceae and Arecaceae), and relatively derived Cephaloleia (e.g., the 'Zingiberales-feeding clade') feed on relatively derived monocots (mostly in the order Zingiberales). Zingiberales feeding and specialization on young rolled Zingiberales leaves have each apparently evolved just once in Cephaloleia.

  15. Capsicum Species: Symptomless Hosts and Reservoirs of Tomato yellow leaf curl virus.

    PubMed

    Polston, J E; Cohen, L; Sherwood, T A; Ben-Joseph, R; Lapidot, M

    2006-05-01

    ABSTRACT Five Capsicum species were tested for susceptibility to Tomato yellow leaf curl virus (TYLCV) and the mild strain of TYLCV (TYLCV-Mld). TYLCV was able to infect 30 of 55 genotypes of C. annuum, one of six genotypes of C. chinense, one of two genotypes of C. baccatum, and the only genotype of C. frutescens tested but was unable to infect the one genotype of C. pubescens tested. This is the first evidence for the susceptibility of C. baccatum, C. chinense, and C. frutescens to TYLCV. Unlike TYLCV isolates, TYLCV-Mld was unable to infect C. chinense. No host differences were observed between the Israeli and Florida isolates of TYLCV. None of the Capsicum species showed symptoms after infection with TYLCV or TYLCV-Mld. TYLCV was detected in fruits of C. annuum, but whiteflies were unable to transmit virus from fruits to plants. White-flies were able to transmit both TYLCV and TYLCV-Mld from infected pepper plants to tomato plants. Pepper plants in research plots were found infected with TYLCV at rates as much as 100%. These data demonstrate the ability of some genotypes of pepper to serve as reservoirs for the acquisition and transmission of TYLCV and TYLCV-Mld.

  16. Assessment of the genetic diversity of tomato yellow leaf curl virus.

    PubMed

    Wan, H J; Yuan, W; Wang, R Q; Ye, Q J; Ruan, M Y; Li, Z M; Zhou, G Z; Yao, Z P; Yang, Y J

    2015-01-01

    The objective of the present study was to analyze the genetic diversity of tomato yellow leaf curl virus (TYLCV). Representative TYLCV sequences were searched in the National Center for Biotechnology Information database. Comprehensive analysis of TYLCV was performed using bioinformatics by examining gene structure, sequence alignments, phylogeny, GC content, and homology. Forty-eight representative TYLCV sequences were selected from 48 regions in 29 countries. The results showed that all TYLCV sequences were 2752-2794 nucleotides in length, which encoded 6 open reading frames (AV1, AV2, AC1, AC2, AC3, and AC4). GC content ranged from 0.41-0.42. Sequence alignment showed a number of insertions and deletions within these TYLCV sequences. Phylogenetic tree results revealed that the sequences were divided into 10 classes; homology of the sequences ranged from 72.8 to 98.6%. All 48 sequences contained the typical structure of TYLCV, including open reading frames and intergenic regions. These results provide a theoretical basis for the identification and evolution of the virus in the future. PMID:25729988

  17. Rapid detection of squash leaf curl virus by loop-mediated isothermal amplification.

    PubMed

    Kuan, Cheng-Ping; Wu, Min-Tze; Lu, Yi-Lin; Huang, Hung-Chang

    2010-10-01

    A loop-mediated isothermal amplification (LAMP) assay was employed to develop a simple and efficient system for the detection of squash leaf curl virus (SLCV) in diseased plants of squash (Cucurbita pepo) and melon (Cucumis melo). Completion of LAMP assay required 30-60 min under isothermal conditions at 65 degrees C by employing a set of four primers targeting SLCV. Although the sensitivity of the LAMP assay and the polymerase chain reaction (PCR) assay was comparable at high virus concentrations, the LAMP assay was by a 10-fold dilution factor more sensitive than the PCR assay for the detection of SLCV in diseased plants. No reaction was detected in the tissues of healthy plants by either the LAMP or the PCR. The LAMP products can be visualized by staining directly in the tube with SYBR Safe DNA gel stain dye. The sensitivity of the SYBR Safe DNA gel stain is similar to analysis by gel electrophoresis. Although both the LAMP and the PCR methods were capable of detecting SLCV in infected tissues of squash and melon, the LAMP method would be more useful than the PCR method for detection of SLCV infection in cucurbitaceous plants because it is more rapid, simple, accurate and sensitive.

  18. Molecular characterization of urdbean (Vigna mungo) germplasm related to resistance against urdbean leaf crinkle virus.

    PubMed

    Binyamin, R; Aslam Khan, M; Khan, A I; Azam Khan, M; Awan, F S; Khan, N A

    2011-01-01

    Urdbean (Vigna mungo) is an important pulse crop grown worldwide. Urdbean leaf crinkle virus (ULCV) is a pathogen of urdbean found in Pakistan that causes huge losses in yield. Forty urdbean varieties/lines were screened against the virus under field conditions during spring season 2009. None of the lines appeared to be highly resistant or resistant. On the basis of a 0-5 disease rating scale and disease severity index, genotypes varied significantly in their reaction to ULCV. Four lines (M-6206, IAM-382-15, IAM-133, and Mash-1) were moderately resistant, eight were rated as moderately susceptible, and 21 as susceptible; the remaining seven lines were highly susceptible. RAPD analyses revealed an extensive amount of variation, which could be used for cultivar identification. Genetic differentiation among urdbean genotypes was similar to the field screening data. The varieties 6065-3 and 6206 were highly susceptible and moderately resistant, respectively, to ULCV under field conditions, confirmed by the RAPD analysis. These varieties were the most diverse varieties in the similarity matrix (67.2%), while the varieties IAM-382-9 and 07M003 were the most similar (98.4%). This information will help in the recognition of available resistant germplasms that can resist this disease and will be utilized for urdbean improvement in Pakistan.

  19. The role of corchorus in spreading of tomato yellow leaf curl virus on tomato in Jeddah, Saudi Arabia.

    PubMed

    Sohrab, Sayed Sartaj

    2016-03-01

    Corchorus (Corchorus capsularis L. and Corchorus olitorius L.) is one of the most important fiber crops grown in tropical and subtropical regions throughout the world. Field survey was conducted and naturally infected leaf samples were collected from corchorus and tomato plants in Jeddah, Saudi Arabia. The causal virus was transmitted by whiteflies to tomato plants and begomovirus infection was confirmed by Polymerase chain reaction. The complete viral genome and associated betasatellites were amplified, cloned and sequenced from both corchorus and tomato samples. The genetic variability and phylogenetic relationships were determined for both isolates (corchorus and tomato). The complete genome sequences showed highest (99.5 % nt) similarity with tomato yellow leaf curl virus (TYLCV) and formed closest cluster with TYLCV-Tomato reported from Jizan and Al-Qasim, Saudi Arabia and betasatellites sequences showed highest similarity (99.8 % nt) with Tomato yellow leaf curl betasatellites-Jeddah followed by Tomato yellow leaf curl Oman betasatellites and formed closed cluster with TYLCV-Tomato. On the basis of results obtained from whiteflies transmission, sequence similarity and phylogenetic relationships; it is concluded that the identified virus could be a variant of TYLCV circulating in the Kingdom. The significance of this study demonstrated that the corchorus is serving as reservoir and alternative host and playing an important role in spreading the begomovirus associated disease in the Kingdom of Saudi Arabia.

  20. The role of corchorus in spreading of tomato yellow leaf curl virus on tomato in Jeddah, Saudi Arabia.

    PubMed

    Sohrab, Sayed Sartaj

    2016-03-01

    Corchorus (Corchorus capsularis L. and Corchorus olitorius L.) is one of the most important fiber crops grown in tropical and subtropical regions throughout the world. Field survey was conducted and naturally infected leaf samples were collected from corchorus and tomato plants in Jeddah, Saudi Arabia. The causal virus was transmitted by whiteflies to tomato plants and begomovirus infection was confirmed by Polymerase chain reaction. The complete viral genome and associated betasatellites were amplified, cloned and sequenced from both corchorus and tomato samples. The genetic variability and phylogenetic relationships were determined for both isolates (corchorus and tomato). The complete genome sequences showed highest (99.5 % nt) similarity with tomato yellow leaf curl virus (TYLCV) and formed closest cluster with TYLCV-Tomato reported from Jizan and Al-Qasim, Saudi Arabia and betasatellites sequences showed highest similarity (99.8 % nt) with Tomato yellow leaf curl betasatellites-Jeddah followed by Tomato yellow leaf curl Oman betasatellites and formed closed cluster with TYLCV-Tomato. On the basis of results obtained from whiteflies transmission, sequence similarity and phylogenetic relationships; it is concluded that the identified virus could be a variant of TYLCV circulating in the Kingdom. The significance of this study demonstrated that the corchorus is serving as reservoir and alternative host and playing an important role in spreading the begomovirus associated disease in the Kingdom of Saudi Arabia. PMID:26925440

  1. Simultaneous detection of papaya ringspot virus, papaya leaf distortion mosaic virus, and papaya mosaic virus by multiplex real-time reverse transcription PCR.

    PubMed

    Huo, P; Shen, W T; Yan, P; Tuo, D C; Li, X Y; Zhou, P

    2015-12-01

    Both the single infection of papaya ringspot virus (PRSV), papaya leaf distortion mosaic virus (PLDMV) or papaya mosaic virus (PapMV) and double infection of PRSV and PLDMV or PapMV which cause indistinguishable symptoms, threaten the papaya industry in Hainan Island, China. In this study, a multiplex real-time reverse transcription PCR (RT-PCR) was developed to detect simultaneously the three viruses based on their distinctive melting temperatures (Tms): 81.0±0.8°C for PRSV, 84.7±0.6°C for PLDMV, and 88.7±0.4°C for PapMV. The multiplex real-time RT-PCR method was specific and sensitive in detecting the three viruses, with a detection limit of 1.0×10(1), 1.0×10(2), and 1.0×10(2) copies for PRSV, PLDMV, and PapMV, respectively. Indeed, the reaction was 100 times more sensitive than the multiplex RT-PCR for PRSV, and 10 times more sensitive than multiplex RT-PCR for PLDMV. Field application of the multiplex real-time RT-PCR demonstrated that some non-symptomatic samples were positive for PLDMV by multiplex real-time RT-PCR but negative by multiplex RT-PCR, whereas some samples were positive for both PRSV and PLDMV by multiplex real-time RT-PCR assay but only positive for PLDMV by multiplex RT-PCR. Therefore, this multiplex real-time RT-PCR assay provides a more rapid, sensitive and reliable method for simultaneous detection of PRSV, PLDMV, PapMV and their mixed infections in papaya.

  2. Simultaneous detection of papaya ringspot virus, papaya leaf distortion mosaic virus, and papaya mosaic virus by multiplex real-time reverse transcription PCR.

    PubMed

    Huo, P; Shen, W T; Yan, P; Tuo, D C; Li, X Y; Zhou, P

    2015-12-01

    Both the single infection of papaya ringspot virus (PRSV), papaya leaf distortion mosaic virus (PLDMV) or papaya mosaic virus (PapMV) and double infection of PRSV and PLDMV or PapMV which cause indistinguishable symptoms, threaten the papaya industry in Hainan Island, China. In this study, a multiplex real-time reverse transcription PCR (RT-PCR) was developed to detect simultaneously the three viruses based on their distinctive melting temperatures (Tms): 81.0±0.8°C for PRSV, 84.7±0.6°C for PLDMV, and 88.7±0.4°C for PapMV. The multiplex real-time RT-PCR method was specific and sensitive in detecting the three viruses, with a detection limit of 1.0×10(1), 1.0×10(2), and 1.0×10(2) copies for PRSV, PLDMV, and PapMV, respectively. Indeed, the reaction was 100 times more sensitive than the multiplex RT-PCR for PRSV, and 10 times more sensitive than multiplex RT-PCR for PLDMV. Field application of the multiplex real-time RT-PCR demonstrated that some non-symptomatic samples were positive for PLDMV by multiplex real-time RT-PCR but negative by multiplex RT-PCR, whereas some samples were positive for both PRSV and PLDMV by multiplex real-time RT-PCR assay but only positive for PLDMV by multiplex RT-PCR. Therefore, this multiplex real-time RT-PCR assay provides a more rapid, sensitive and reliable method for simultaneous detection of PRSV, PLDMV, PapMV and their mixed infections in papaya. PMID:26666186

  3. Molecular analysis of six segments of tobacco leaf enation virus, a novel phytoreovirus from tobacco.

    PubMed

    Picton, Anabela; Potgieter, Christiaan; Rey, Marie Emma Christine

    2007-10-01

    Tobacco leaf enation virus (TLEV) is a putative member of the genus Phytoreovirus within the family Reoviridae. Previous western blot analysis of structural viral proteins (apparent molecular weights of 93 kDa; 58 kDa; 48 kDa; 39 kDa and 36 kDa) associated with TLEV, isolated from infected tobacco in South Africa, suggested that these proteins may correspond to structural Wound tumor virus (WTV) proteins. To further establish the nature of this novel virus disease phenotype in tobacco, molecular characterization of six dsRNA components was undertaken. Full-length cDNA clones were obtained by an optimized modified single-primer amplification sequence-independent dsRNA cloning method. Results of this study revealed the conserved terminal sequence: 5'GG(U/C)...UGAU 3' of segments S6-S12, while adjacent to these conserved terminal sequences are imperfect inverted repeats (7-15 bp in length), both features being common to reoviruses. The complete nucleotide sequences of segments S5 (2,610 bp), S7 (1,740 bp), S8 (1,439 bp), S10 (1,252 bp), S11 (1,187 bp) and S12 (836 bp) were determined. Comparison of full-length nucleotide sequences with corresponding segments of other phytoreoviruses, Rice gall dwarf virus (RGDV), Rice dwarf virus (RDV) and WTV has shown nucleotide and predicted amino acid identities within the range of 30-60%. TLEV consistently shows a higher identity to WTV than to other phytoreovirus species where sequence data is available. Each segment had a single predicted open reading frame encoding proteins with calculated molecular weights of S5 (90.6 kDa); S7 (58.1 kDa); S8 (47.7 kDa); S10 (39.8 kDa); S11 (35 kDa) and S12 (19.5 kDa). The relatively low nucleotide and amino acid identity to other members of the genus demonstrates that TLEV is a novel phytoreovirus, distinct from the only other reported dicotyledenous-infecting WTV and is the first phytoreovirus reported to emerge in Africa.

  4. Conservation of major and minor jelly-roll capsid proteins in Polinton (Maverick) transposons suggests that they are bona fide viruses

    PubMed Central

    2014-01-01

    Reviewers This article was reviewed by Lakshminarayan M. Iyer and I. King Jordan. For complete reviews, see the Reviewers’ Reports section. Polintons (also known as Mavericks) and Tlr elements of Tetrahymena thermophila represent two families of large DNA transposons widespread in eukaryotes. Here, we show that both Polintons and Tlr elements encode two key virion proteins, the major capsid protein with the double jelly-roll fold and the minor capsid protein, known as the penton, with the single jelly-roll topology. This observation along with the previously noted conservation of the genes for viral genome packaging ATPase and adenovirus-like protease strongly suggests that Polintons and Tlr elements combine features of bona fide viruses and transposons. We propose the name ‘Polintoviruses’ to denote these putative viruses that could have played a central role in the evolution of several groups of DNA viruses of eukaryotes. PMID:24773695

  5. Leaf rolling and stem fasciation in grass pea (Lathyrus sativus L.) mutant are mediated through glutathione-dependent cellular and metabolic changes and associated with a metabolic diversion through cysteine during phenotypic reversal.

    PubMed

    Talukdar, Dibyendu; Talukdar, Tulika

    2014-01-01

    A Lathyrus sativus L. mutant isolated in ethylmethane sulfonate-treated M2 progeny of mother variety BioL-212 and designated as rlfL-1 was characterized by inwardly rolled-leaf and stem and bud fasciations. The mutant exhibited karyomorphological peculiarities in both mitosis and meiosis with origin of aneuploidy. The mitosis was vigorous with high frequency of divisional cells and their quick turnover presumably steered cell proliferations. Significant transcriptional upregulations of cysteine and glutathione synthesis and concomitant stimulations of glutathione-mediated antioxidant defense helped rlfL-1 mutant to maintain balanced reactive oxygen species (ROS) metabolisms, as deduced by ROS-imaging study. Glutathione synthesis was shut down in buthionine sulfoximine- (BSO-) treated mother plant and mutant, and leaf-rolling and stems/buds fasciations in the mutant were reversed, accompanied by normalization of mitotic cell division process. Antioxidant defense was downregulated under low glutathione-redox but cysteine-desulfurations and photorespiratory glycolate oxidase transcripts were markedly overexpressed, preventing cysteine overaccumulation but resulted in excess H2O2 in BSO-treated mutant. This led to oxidative damage in proliferating cells, manifested by severe necrosis in rolled-leaf and fasciated stems. Results indicated vital role of glutathione in maintaining abnormal proliferations in plant organs, and its deficiency triggered phenotypic reversal through metabolic diversions of cysteine and concomitant cellular and metabolic modulations. PMID:24987684

  6. Leaf rolling and stem fasciation in grass pea (Lathyrus sativus L.) mutant are mediated through glutathione-dependent cellular and metabolic changes and associated with a metabolic diversion through cysteine during phenotypic reversal.

    PubMed

    Talukdar, Dibyendu; Talukdar, Tulika

    2014-01-01

    A Lathyrus sativus L. mutant isolated in ethylmethane sulfonate-treated M2 progeny of mother variety BioL-212 and designated as rlfL-1 was characterized by inwardly rolled-leaf and stem and bud fasciations. The mutant exhibited karyomorphological peculiarities in both mitosis and meiosis with origin of aneuploidy. The mitosis was vigorous with high frequency of divisional cells and their quick turnover presumably steered cell proliferations. Significant transcriptional upregulations of cysteine and glutathione synthesis and concomitant stimulations of glutathione-mediated antioxidant defense helped rlfL-1 mutant to maintain balanced reactive oxygen species (ROS) metabolisms, as deduced by ROS-imaging study. Glutathione synthesis was shut down in buthionine sulfoximine- (BSO-) treated mother plant and mutant, and leaf-rolling and stems/buds fasciations in the mutant were reversed, accompanied by normalization of mitotic cell division process. Antioxidant defense was downregulated under low glutathione-redox but cysteine-desulfurations and photorespiratory glycolate oxidase transcripts were markedly overexpressed, preventing cysteine overaccumulation but resulted in excess H2O2 in BSO-treated mutant. This led to oxidative damage in proliferating cells, manifested by severe necrosis in rolled-leaf and fasciated stems. Results indicated vital role of glutathione in maintaining abnormal proliferations in plant organs, and its deficiency triggered phenotypic reversal through metabolic diversions of cysteine and concomitant cellular and metabolic modulations.

  7. Leaf Rolling and Stem Fasciation in Grass Pea (Lathyrus sativus L.) Mutant Are Mediated through Glutathione-Dependent Cellular and Metabolic Changes and Associated with a Metabolic Diversion through Cysteine during Phenotypic Reversal

    PubMed Central

    Talukdar, Dibyendu; Talukdar, Tulika

    2014-01-01

    A Lathyrus sativus L. mutant isolated in ethylmethane sulfonate-treated M2 progeny of mother variety BioL-212 and designated as rlfL-1 was characterized by inwardly rolled-leaf and stem and bud fasciations. The mutant exhibited karyomorphological peculiarities in both mitosis and meiosis with origin of aneuploidy. The mitosis was vigorous with high frequency of divisional cells and their quick turnover presumably steered cell proliferations. Significant transcriptional upregulations of cysteine and glutathione synthesis and concomitant stimulations of glutathione-mediated antioxidant defense helped rlfL-1 mutant to maintain balanced reactive oxygen species (ROS) metabolisms, as deduced by ROS-imaging study. Glutathione synthesis was shut down in buthionine sulfoximine- (BSO-) treated mother plant and mutant, and leaf-rolling and stems/buds fasciations in the mutant were reversed, accompanied by normalization of mitotic cell division process. Antioxidant defense was downregulated under low glutathione-redox but cysteine-desulfurations and photorespiratory glycolate oxidase transcripts were markedly overexpressed, preventing cysteine overaccumulation but resulted in excess H2O2 in BSO-treated mutant. This led to oxidative damage in proliferating cells, manifested by severe necrosis in rolled-leaf and fasciated stems. Results indicated vital role of glutathione in maintaining abnormal proliferations in plant organs, and its deficiency triggered phenotypic reversal through metabolic diversions of cysteine and concomitant cellular and metabolic modulations. PMID:24987684

  8. Sweet pepper confirmed as a reservoir host for tomato yellow leaf curl virus by both agro-inoculation and whitefly-mediated inoculation.

    PubMed

    Kil, Eui-Joon; Byun, Hee-Seong; Kim, Sunhoo; Kim, Jaedeok; Park, Jungan; Cho, Seungchan; Yang, Dong-Cheol; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Kim, Ji-Kwang; Lee, Sukchan

    2014-09-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, has a single-stranded DNA genome. TYLCV can induce severe disease symptoms on tomato plants, but other hosts plants such as cucurbits and peppers are asymptomatic. A full-length DNA clone of a Korean TYLCV isolate was constructed by rolling-circle amplification from TYLCV-infected tomatoes in Korea. To assess relative susceptibility of sweet pepper varieties to TYLCV, 19 cultivars were inoculated with cloned TYLCV by agro-inoculation. All TYLCV-infected sweet peppers were asymptomatic, even though Southern hybridization and polymerase chain reaction analysis showed TYLCV genomic DNA accumulation in roots, stems, and newly produced shoots. Southern hybridization indicated that TYLCV replicated and moved systemically from agro-inoculated apical shoot tips to roots or newly produced shoots of sweet peppers. Whitefly-mediated inoculation experiments showed that TYLCV can be transmitted to tomatoes from TYLCV-infected sweet peppers. Taken together, these results indicate that sweet pepper can be a reservoir for TYLCV in nature.

  9. Sweet pepper confirmed as a reservoir host for tomato yellow leaf curl virus by both agro-inoculation and whitefly-mediated inoculation.

    PubMed

    Kil, Eui-Joon; Byun, Hee-Seong; Kim, Sunhoo; Kim, Jaedeok; Park, Jungan; Cho, Seungchan; Yang, Dong-Cheol; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Kim, Ji-Kwang; Lee, Sukchan

    2014-09-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, has a single-stranded DNA genome. TYLCV can induce severe disease symptoms on tomato plants, but other hosts plants such as cucurbits and peppers are asymptomatic. A full-length DNA clone of a Korean TYLCV isolate was constructed by rolling-circle amplification from TYLCV-infected tomatoes in Korea. To assess relative susceptibility of sweet pepper varieties to TYLCV, 19 cultivars were inoculated with cloned TYLCV by agro-inoculation. All TYLCV-infected sweet peppers were asymptomatic, even though Southern hybridization and polymerase chain reaction analysis showed TYLCV genomic DNA accumulation in roots, stems, and newly produced shoots. Southern hybridization indicated that TYLCV replicated and moved systemically from agro-inoculated apical shoot tips to roots or newly produced shoots of sweet peppers. Whitefly-mediated inoculation experiments showed that TYLCV can be transmitted to tomatoes from TYLCV-infected sweet peppers. Taken together, these results indicate that sweet pepper can be a reservoir for TYLCV in nature. PMID:24777825

  10. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton leaf curl disease (CLCuD) in the Indian subcontinent is associated with several distinct monopartite begomoviruses and DNA satellites. However, only a single begomovirus was associated with breakdown of resistance against CLCuD in previously resistant cotton varieties. The monopartite begomov...

  11. Molecular characterization and prevalence of two capulaviruses: Alfalfa leaf curl virus from France and Euphorbia caput-medusae latent virus from South Africa.

    PubMed

    Bernardo, Pauline; Muhire, Brejnev; François, Sarah; Deshoux, Maëlle; Hartnady, Penelope; Farkas, Kata; Kraberger, Simona; Filloux, Denis; Fernandez, Emmanuel; Galzi, Serge; Ferdinand, Romain; Granier, Martine; Marais, Armelle; Monge Blasco, Pablo; Candresse, Thierry; Escriu, Fernando; Varsani, Arvind; Harkins, Gordon W; Martin, Darren P; Roumagnac, Philippe

    2016-06-01

    Little is known about the prevalence, diversity, evolutionary processes, genomic structures and population dynamics of viruses in the divergent geminivirus lineage known as the capulaviruses. We determined and analyzed full genome sequences of 13 Euphorbia caput-medusae latent virus (EcmLV) and 26 Alfalfa leaf curl virus (ALCV) isolates, and partial genome sequences of 23 EcmLV and 37 ALCV isolates. While EcmLV was asymptomatic in uncultivated southern African Euphorbia caput-medusae, severe alfalfa disease symptoms were associated with ALCV in southern France. The prevalence of both viruses exceeded 10% in their respective hosts. Besides using patterns of detectable negative selection to identify ORFs that are probably functionally expressed, we show that ALCV and EcmLV both display evidence of inter-species recombination and biologically functional genomic secondary structures. Finally, we show that whereas the EcmLV populations likely experience restricted geographical dispersion, ALCV is probably freely moving across the French Mediterranean region.

  12. Monitoring the dynamics of emergence of a non-canonical recombinant of Tomato yellow leaf curl virus and displacement of its parental viruses in tomato.

    PubMed

    Belabess, Z; Dallot, S; El-Montaser, S; Granier, M; Majde, M; Tahiri, A; Blenzar, A; Urbino, C; Peterschmitt, M

    2015-12-01

    Recombinant viruses are increasingly being reported but the dynamics of their emergence is rarely documented. A new recombinant Tomato yellow leaf curl virus (TYLCV-IS76) was detected for the first time in 2010 in Southern Morocco (Souss). An original diagnostic tool was needed to fit its unusual recombination profile. Although IS76 was detected following the appearance of Tylc symptoms on tolerant tomato plants, symptoms could not be associated to IS76 or to a synergy with criniviruses. According to infection profiles of Tylc-associated viruses determined on 879 plant samples collected between 1998 and 2014 and a Bayesian inference applied to genomic sequences of representatives of TYLCV, IS76 emerged in Southern Morocco at the end of the 1990s, replaced the parental viruses between 2004 and 2012 in Souss and is spreading towards the North of Morocco. The emergence of IS76 coincides with the increasing use of tolerant cultivars in the 2000s. PMID:26519598

  13. Complete nucleotide sequences of okra isolates of Cotton leaf curl Gezira virus and their associated DNA-beta from Niger.

    PubMed

    Shih, S L; Kumar, S; Tsai, W S; Lee, L M; Green, S K

    2009-01-01

    Okra (Abelmoschus esculentus) is a major crop in Niger. In the fall of 2007, okra leaf curl disease was observed in Niger and the begomovirus and DNA-beta satellite were found associated with the disease. The complete nucleotide sequences of DNA-A (FJ469626 and FJ469627) and associated DNA-beta satellites (FJ469628 and FJ469629) were determined from two samples. This is the first report of molecular characterization of okra-infecting begomovirus and their associated DNA-beta from Niger. The begomovirus and DNA-beta have been identified as Cotton leaf curl Gezira virus and Cotton leaf curl Gezira betasatellite, respectively, which are reported to also infect okra in Egypt, Mali and Sudan.

  14. Tomato chlorotic leaf distortion virus, a new bipartite begomovirus infecting Solanum lycopersicum and Capsicum chinense in Venezuela.

    PubMed

    Zambrano, Karla; Geraud-Pouey, Francis; Chirinos, Doris; Romay, Gustavo; Marys, Edgloris

    2011-12-01

    Virus isolate T217L was obtained from a diseased tomato (Solanum lycopersicum) plant showing leaf deformation and chlorotic mottle symptoms near Maracaibo in the state of Zulia, Venezuela. Full-length DNA-A and DNA-B molecules of T217L were cloned and sequenced. The genome organization of T217L was identical to the bipartite genomes of other begomoviruses described from the Americas. Characteristic disease symptoms were reproduced in S. lycopersicum and Capsicum annum plants inoculated using the cloned viral DNA-A and DNA-B components, confirming disease aetiology. A sequence analysis of DNA-A showed that the T217L isolate has the highest sequence identity (84%) with sida yellow mosaic Yucatan virus (SiYMYuV), sida golden mosaic Honduras virus (SiGMHV) and bean dwarf mosaic virus (BDMV) isolates. This is less than the 89% identity in the DNA-A component that has been defined as the threshold value for the demarcation of species in the genus Begomovirus. The molecular data show that isolate T217L belongs to a novel tentative begomovirus species, for which the name tomato chlorotic leaf distortion virus is proposed. TCLDV was also detected in symptomatic C. chinense plants growing near the T217L-infected plant.

  15. In Vitro Inhibition of Cytopathic Effect of Influenza Virus and Human Immunodeficiency Virus by Bamboo Leaf Extract Solution and Sodium Copper Chlorophyllin

    PubMed Central

    Ito, Akiko; Tsuneki, Akeno; Yoshida, Yu; Ryoke, Kazuo; Kaidoh, Toshiyuki; Kageyama, Seiji

    2016-01-01

    Background Although the link between oral and oropharyngeal health status and susceptibility to infection has long been recognized, there is a limit to the selection of antiseptics for oral care. Methods Madin-Darby canine kidney (MDCK) cells were exposed to influenza virus and cultured in the presence or absence of test reagents: bamboo leaf extract solution and sodium copper chrolophyllin. MDCK cells were pre-incubated with the reagents to assess the inhibitory activity at adsorption (viral attachment). Similarly, anti-HIV activity and the inhibitory mechanism at adsorption were assessed by MT-2 cell culture system. Mixture of HIV and bamboo leaf extract solution was fixed and examined by transmission electron microscopy. Results The 50% inhibitory concentration (IC50) of bamboo leaf extract solution against influenza virus and the 50% cytotoxic concentration (CC50) in MDCK cells of the solution lay between 0.0313–0.0625% and 0.5–1.0%. The solution inhibited the influenza virus adsorption at the concentration of 0.5% (P < 0.05). The values of IC50 and CC50 of sodium copper chlorophyllin lay between 50–100 µM and 200–400 µM, respectively. This inhibited the virus adsorption at 200 µM (P < 0.05). The bamboo leaf extract solution showed values of IC50 against HIV and CC50 in MT-2 cells at around 0.0313% and between 0.25–0.5%, respectively. This solution inhibited HIV adsorption at 1.25% (P < 0.05). The IC50 and CC50 of sodium copper chlorophyllin lay between 50–100 µM and 200–400 µM, respectively. Sodium copper chlorophyllin inhibited HIV adsorption at 2.5 mM (P < 0.05). HIV particles survived after the exposure to 0.5% bamboo leaf extract solution. Conclusion Sodium copper chlorophyllin exerted antiviral activities against influenza virus and HIV as the major ingredient of bamboo leaf extract solution by blocking adsorption. This mechanism of action is different completely from the one of povidone-iodine. PMID:27046952

  16. The relationship between Pepper mottle virus source leaf and spread of infection through the stem of Capsicum sp.

    PubMed

    Murphy, J F

    2002-09-01

    Pepper mottle virus (PepMoV) systemically infects Capsicum sp. in a typical source-to-sink manner with movement through the stem occurring in a predictable pattern. This study was carried out to determine the relationship between the inoculated leaf as a source of inoculum and the spread of PepMoV infection through the stem. C. annuum 'Early Calwonder' plants were mechanically inoculated onto the first leaf with PepMoV and sets of 30 plants had their inoculated leaves removed each day from 1 through 7 days post-inoculation (dpi) with the inoculated leaves tested for infection by ELISA at the time of excision. Beginning at 2 dpi, PepMoV infection in the stem of plants with the inoculated leaf excised and plants of a nonexcision control treatment was determined using immuno-tissue blot analysis. PepMoV was detected in inoculated leaves beginning at 3 dpi with the percentage of infected leaves increasing each day through 7 dpi. PepMoV was first detected in the stem of inoculated plants of the 3 dpi excision treatment. The accumulation and extent of spread of infection in the stem was similar for plants that had their inoculated leaf removed at a time preceding detection by ELISA to plants in the nonexcision control treatment. These findings suggest that once virus is allowed to enter the stem from the inoculated leaf, subsequent spread of infection through the stem is a process independent from the source leaf. PMID:12209317

  17. The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World

    PubMed Central

    Lefeuvre, Pierre; Martin, Darren P.; Harkins, Gordon; Lemey, Philippe; Gray, Alistair J. A.; Meredith, Sandra; Lakay, Francisco; Monjane, Adérito; Lett, Jean-Michel; Varsani, Arvind; Heydarnejad, Jahangir

    2010-01-01

    The ongoing global spread of Tomato yellow leaf curl virus (TYLCV; Genus Begomovirus, Family Geminiviridae) represents a serious looming threat to tomato production in all temperate parts of the world. Whereas determining where and when TYLCV movements have occurred could help curtail its spread and prevent future movements of related viruses, determining the consequences of past TYLCV movements could reveal the ecological and economic risks associated with similar viral invasions. Towards this end we applied Bayesian phylogeographic inference and recombination analyses to available TYLCV sequences (including those of 15 new Iranian full TYLCV genomes) and reconstructed a plausible history of TYLCV's diversification and movements throughout the world. In agreement with historical accounts, our results suggest that the first TYLCVs most probably arose somewhere in the Middle East between the 1930s and 1950s (with 95% highest probability density intervals 1905–1972) and that the global spread of TYLCV only began in the 1980s after the evolution of the TYLCV-Mld and -IL strains. Despite the global distribution of TYLCV we found no convincing evidence anywhere other than the Middle East and the Western Mediterranean of epidemiologically relevant TYLCV variants arising through recombination. Although the region around Iran is both the center of present day TYLCV diversity and the site of the most intensive ongoing TYLCV evolution, the evidence indicates that the region is epidemiologically isolated, which suggests that novel TYLCV variants found there are probably not direct global threats. We instead identify the Mediterranean basin as the main launch-pad of global TYLCV movements. PMID:21060815

  18. Differential expression analyses of host genes involved in systemic infection of Tomato leaf curl New Delhi virus (ToLCNDV).

    PubMed

    Naqvi, Afsar Raza; Sarwat, Maryam; Pradhan, Bhubaneswar; Choudhury, Nirupam Roy; Haq, Qazi Mohd Rizwanul; Mukherjee, Sunil Kumar

    2011-09-01

    Tomato leaf curl viruses (ToLCV) infect tomato plants and eventually cause several phenotypic defects, notably in the leaves in the form of upward curling. The entry of virus triggers plants' basal defense responses which eventually introduce temporal changes in the transcriptome to evade the pathogen attack. In this study, we have identified about 20 tomato ESTs using subtractive hybridization that were induced in tomato leaves upon agro-infection with the constructs bearing the dimers of Tomato leaf curl New Delhi virus (ToLCNDV) DNA-A and DNA-B components. The induced ESTs belonged to the class of genes that play crucial roles in innate immunity, plants metabolism and ethylene signaling. The expression of few of these ESTs was validated by northern blot analysis and two out of six selected genes expressed exclusively in the infected leaf tissues. Besides leaves, the expression status of selected genes was checked in a wide variety of tissues (flower, fruit, stem and root) of both healthy and infected plants by RT-PCR. These results suggest that the flower and fruit tissues, similar to leaves, exhibited induction of most of the genes while the stem and root tissues suffered from down-regulation. Overall, these results indicate that the hosts' transcriptome undergoes considerable changes in response to viral infection. PMID:21600246

  19. Detection and quantitation of the new world Squash leaf curl virus by TaqMan real-time PCR.

    PubMed

    Abrahamian, Peter E; Abou-Jawdah, Yusuf

    2013-07-01

    Squash leaf curl diseases are caused by distinct virus species that are separated into two major phylogenetic groups, western and eastern hemisphere groups. The western group includes the new world Squash leaf curl virus (SLCV) which causes major losses to cucurbit production and induces severe stunting and leaf curl in squash plants. A TaqMan-based real time polymerase chain reaction (qPCR) assay has been developed for detection and quantitation of SLCV. Designed primers and probe targeted the AV1 (coat protein) gene and in silico analysis showed that they detect a large number of SLCV isolates. The developed assay could detect the virus in 18fg of total nucleic acid and 30 genomic units. The qPCR assay was about 1000 times more sensitive than PCR and amplified successfully SLCV from a wide range of cucurbit hosts and from viruliferous whiteflies. The developed qPCR assay should be suitable for detection and quantitation purposes for all reported SLCV isolates of the western hemisphere.

  20. Long-distance movement of Cauliflower mosaic virus and host defence responses in Arabidopsis follow a predictable pattern that is determined by the leaf orthostichy.

    PubMed

    Roberts, Karen; Love, Andrew J; Laval, Valérie; Laird, Janet; Tomos, A Deri; Hooks, Mark A; Milner, Joel J

    2007-01-01

    Long-distance virus transport takes place through the vascular system and is dependent on the movement of photoassimilates. Here, patterns of symptom development, virus movement and gene expression were analysed in Arabidopsis following inoculation with Cauliflower mosaic virus (CaMV) on a single leaf. Virus accumulation and expression of markers for the salicylic acid (SA) and ethylene/jasmonate (Et/JA) defence pathways, PR-1 and PDF1.2, were analysed on a leaf-by-leaf basis by real-time reverse transcription polymerase chain reaction (qRT-PCR). Virus spread followed a strictly defined pattern identical to that of a source-sink relationship. This was exploited to study differences between local and systemic defence responses in a developmental and spatial manner. In infected plants, PR-1 transcripts accumulated primarily but not exclusively in leaves with a direct vascular connection to the inoculated leaf. Abundances fell significantly as virus accumulated. By contrast, PDF1.2 transcripts were significantly lower than in controls in all leaves at early stages of infection, but recovered as virus accumulated. Virus and PR-1 transcript abundances are negatively correlated, and SA- and Et/JA-mediated signalling of gene expression occurs independently of the presence of virus. Although SA-dependent signalling responses were mainly linked to the orthostichy, Et/JA-dependent responses were independent of vascular connections. PMID:17688586

  1. Genome Sequences of Three Apple chlorotic leaf spot virus Isolates from Hawthorns in China.

    PubMed

    Guo, Wei; Zheng, Wenyan; Wang, Mei; Li, Xiaohong; Ma, Yue; Dai, Hongyan

    2016-01-01

    The genome sequences of Apple chlorotic leaf spot virus (ACLSV) isolates from three accessions of hawthorns (Crataegus pinnatifida) grown at Shenyang Agricultural University were determined using Illumina RNA-seq. To confirm the assembly data from the de novo sequencing, two ACLSV genomic sequences (SY01 and SY02) were sequenced using the Sanger method. The SY01 and SY02 sequences obtained with the Sanger method showed 99.5% and 99.7% nucleotide identity with the transcriptome data, respectively. The genome sequences of the hawthorn isolates SY01, SY02 and SY03 (GenBank accession nos. KM207212, KU870524 and KU870525, respectively) consisted of 7,543, 7,561 and 7,545 nucleotides, respectively, excluding poly-adenylated tails. Sequence analysis revealed that these hawthorn isolates shared an overall nucleotide identity of 82.8-92.1% and showed the highest identity of 90.3% for isolate YH (GenBank accession no. KC935955) from pear and the lowest identity of 67.7% for isolate TaTao5 (GenBank accession no. EU223295) from peach. Hawthorn isolate sequences were similar to those of 'B6 type' ACLSV. The relationship between ACLSV isolates largely depends upon the host species. This represents the first comparative study of the genome sequences of ACLSV isolates from hawthorns. PMID:27519059

  2. Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses

    PubMed Central

    Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

    2014-01-01

    The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000 ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

  3. Tomato yellow leaf curl virus alters the host preferences of its vector Bemisia tabaci.

    PubMed

    Fang, Yong; Jiao, Xiaoguo; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Shi, Xiaobin; Chen, Gong; Su, Qi; Yang, Xin; Pan, Huipeng; Zhang, Youjun

    2013-01-01

    Bemisia tabaci, the whitefly vector of Tomato yellow leaf curl virus (TYLCV), seriously reduces tomato production and quality. Here, we report the first evidence that infection by TYLCV alters the host preferences of invasive B. tabaci B (Middle East-Minor Asia 1) and Q (Mediterranean genetic group), in which TYLCV-free B. tabaci Q preferred to settle on TYLCV-infected tomato plants over healthy ones. TYLCV-free B. tabaci B, however, preferred healthy tomato plants to TYLCV-infected plants. In contrast, TYLCV-infected B. tabaci, either B or Q, did not exhibit a preference between TYLCV-infected and TYLCV-free tomato plants. Based on gas chromatography-mass spectrometry (GCMS)analysis of plant terpene volatiles, significantly more β-myrcene, thymene, β-phellandrene, caryophyllene, (+)-4-carene, and α-humulene were released from the TYLCV-free tomato plants than from the TYLCV-infected ones. The results indicate TYLCV can alter the host preferences of its vector Bemisia tabaci B and Q. PMID:24096821

  4. Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses.

    PubMed

    Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

    2014-01-01

    The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000 ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

  5. Genome Sequences of Three Apple chlorotic leaf spot virus Isolates from Hawthorns in China

    PubMed Central

    Zheng, Wenyan; Wang, Mei; Li, Xiaohong; Ma, Yue

    2016-01-01

    The genome sequences of Apple chlorotic leaf spot virus (ACLSV) isolates from three accessions of hawthorns (Crataegus pinnatifida) grown at Shenyang Agricultural University were determined using Illumina RNA-seq. To confirm the assembly data from the de novo sequencing, two ACLSV genomic sequences (SY01 and SY02) were sequenced using the Sanger method. The SY01 and SY02 sequences obtained with the Sanger method showed 99.5% and 99.7% nucleotide identity with the transcriptome data, respectively. The genome sequences of the hawthorn isolates SY01, SY02 and SY03 (GenBank accession nos. KM207212, KU870524 and KU870525, respectively) consisted of 7,543, 7,561 and 7,545 nucleotides, respectively, excluding poly-adenylated tails. Sequence analysis revealed that these hawthorn isolates shared an overall nucleotide identity of 82.8–92.1% and showed the highest identity of 90.3% for isolate YH (GenBank accession no. KC935955) from pear and the lowest identity of 67.7% for isolate TaTao5 (GenBank accession no. EU223295) from peach. Hawthorn isolate sequences were similar to those of ‘B6 type’ ACLSV. The relationship between ACLSV isolates largely depends upon the host species. This represents the first comparative study of the genome sequences of ACLSV isolates from hawthorns. PMID:27519059

  6. Safety assessment of leaf curl virus resistant tomato developed using viral derived sequences.

    PubMed

    Singh, Abinav K; Praveen, Shelly; Singh, Bhanu P; Varma, Anupam; Arora, Naveen

    2009-12-01

    Genetic engineering of food crops has significantly influenced the agricultural productivity over the past two decades. It has proved a valuable tool, offering crops with higher yields, improved nutritional quality, resistance against pesticides, herbicides and tolerance against abiotic stresses. However, the safety assessment of genetically engineered (GE) crops is prerequisite before introduction into human food chain. The present study was aimed to assess the toxicity and allergenicity of leaf curl virus resistant GE tomato compared to its wild-type species. Balb/c mice fed with genetically engineered or wild-type tomato did not show significant differences in growth, body weight (P > 0.05) and food consumption when compared with control mice. Values for serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase, urea and cholesterol were comparable in GE and wild-type tomato fed mice. Mice immunized with GE or wild-type tomato extract showed low IgE response. Lung histology of ovalbumin fed mice showed bronchoconstriction with eosinophilic infiltration whereas GE or wild-type tomato showed no cellular infiltration with normal airways. Genetically engineered and wild-type tomato sensitized mice demonstrated similar IL-4 release in splenic cell culture supernatant. GE and wild tomato extract on ELISA showed comparable IgE binding (P > 0.05) with food allergic patients' sera. In conclusion, genetically engineered tomato showed no toxicity in mice and allergenicity is similar to the wild-type tomato.

  7. Immunity to tomato yellow leaf curl virus in transgenic tomato is associated with accumulation of transgene small RNA.

    PubMed

    Leibman, Diana; Prakash, Shanmugam; Wolf, Dalia; Zelcer, Aaron; Anfoka, Ghandi; Haviv, Sabrina; Brumin, Marina; Gaba, Victor; Arazi, Tzahi; Lapidot, Moshe; Gal-On, Amit

    2015-11-01

    Gene silencing is a natural defense response of plants against invading RNA and DNA viruses. The RNA post-transcriptional silencing system has been commonly utilized to generate transgenic crop plants that are "immune" to plant virus infection. Here, we applied this approach against the devastating DNA virus tomato yellow leaf curl virus (TYLCV) in its host tomato (Solanum lycopersicum L.). To generate broad resistance to a number of different TYLCV viruses, three conserved sequences (the intergenic region [NCR], V1-V2 and C1-C2 genes) from the genome of the severe virus (TYLCV) were synthesized as a single insert and cloned into a hairpin configuration in a binary vector, which was used to transform TYLCV-susceptible tomato plants. Eight of 28 independent transgenic tomato lines exhibited immunity to TYLCV-Is and to TYLCV-Mld, but not to tomato yellow leaf curl Sardinia virus, which shares relatively low sequence homology with the transgene. In addition, a marker-free (nptII-deleted) transgenic tomato line was generated for the first time by Agrobacterium-mediated transformation without antibiotic selection, followed by screening of 1180 regenerated shoots by whitefly-mediated TYLCV inoculation. Resistant lines showed a high level of transgene-siRNA (t-siRNA) accumulation (22% of total small RNA) with dominant sizes of 21 nt (73%) and 22 nt (22%). The t-siRNA displayed hot-spot distribution ("peaks") along the transgene, with different distribution patterns than the viral-siRNA peaks observed in TYLCV-infected tomato. A grafting experiment demonstrated the mobility of 0.04% of the t-siRNA from transgenic rootstock to non-transformed scion, even though scion resistance against TYLCV was not achieved. PMID:26255053

  8. A simple, rapid and inexpensive method for localization of Tomato yellow leaf curl virus and Potato leafroll virus in plant and insect vectors.

    PubMed

    Ghanim, Murad; Brumin, Marina; Popovski, Smadar

    2009-08-01

    A simple, rapid, inexpensive method for the localization of virus transcripts in plant and insect vector tissues is reported here. The method based on fluorescent in situ hybridization using short DNA oligonucleotides complementary to an RNA segment representing a virus transcript in the infected plant or insect vector. The DNA probe harbors a fluorescent molecule at its 5' or 3' ends. The protocol: simple fixation, hybridization, minimal washing and confocal microscopy, provides a highly specific signal. The reliability of the protocol was tested by localizing two phloem-limited plant virus transcripts in infected plants and insect tissues: Tomato yellow leaf curl virus (TYLCV) (Begomovirus: Geminiviridae), exclusively transmitted by the whitefly Bemisia tabaci (Gennadius) in a circulative non-propagative manner, and Potato leafroll virus (Polerovirus: Luteoviridae), similarly transmitted by the aphid Myzus persicae (Sulzer). Transcripts for both viruses were localized specifically to the phloem sieve elements of infected plants, while negative controls showed no signal. TYLCV transcripts were also localized to the digestive tract of B. tabaci, confirming TYLCV route of transmission. Compared to previous methods for localizing virus transcripts in plant and insect tissues that include complex steps for in-vitro probe preparation or antibody raising, tissue fixation, block preparation, sectioning and hybridization, the method described below provides very reliable, convincing, background-free results with much less time, effort and cost. PMID:19406154

  9. SnRK1 Phosphorylation of AL2 Delays Cabbage Leaf Curl Virus Infection in Arabidopsis

    PubMed Central

    Shen, Wei; Dallas, Mary Beth; Goshe, Michael B.

    2014-01-01

    ABSTRACT Geminivirus AL2/C2 proteins play key roles in establishing infection and causing disease in their plant hosts. They are involved in viral gene expression, counter host defenses by suppressing transcriptional gene silencing, and interfere with the host signaling involved in pathogen resistance. We report here that begomovirus and curtovirus AL2/C2 proteins interact strongly with host geminivirus Rep-interacting kinases (GRIKs), which are upstream activating kinases of the protein kinase SnRK1, a global regulator of energy and nutrient levels in plants. We used an in vitro kinase system to show that GRIK-activated SnRK1 phosphorylates recombinant AL2/C2 proteins from several begomoviruses and to map the SnRK1 phosphorylation site to serine-109 in the AL2 proteins of two New World begomoviruses: Cabbage Leaf Curl Virus (CaLCuV) and Tomato mottle virus. A CaLCuV AL2 S109D phosphomimic mutation did not alter viral DNA levels in protoplast replication assays. In contrast, the phosphomimic mutant was delayed for symptom development and viral DNA accumulation during infection of Arabidopsis thaliana, demonstrating that SnRK1 contributes to host defenses against CaLCuV. Our observation that serine-109 is not conserved in all AL2/C2 proteins that are SnRK1 substrates in vitro suggested that phosphorylation of viral proteins by plant kinases contributes to the evolution of geminivirus-host interactions. IMPORTANCE Geminiviruses are single-stranded DNA viruses that cause serious diseases in many crops. Dicot-infecting geminiviruses carry genes that encode multifunctional AL2/C2 proteins that are essential for infection. However, it is not clear how AL2/C2 proteins are regulated. Here, we show that the host protein kinase SnRK1, a central regulator of energy balance and nutrient metabolism in plants, phosphorylates serine-109 in AL2 proteins of three subgroups of New World begomoviruses, resulting in a delay in viral DNA accumulation and symptom appearance. Our results

  10. Introgression of cotton leaf curl virus-resistant genes from Asiatic cotton (Gossypium arboreum) into upland cotton (G. hirsutum).

    PubMed

    Ahmad, S; Mahmood, K; Hanif, M; Nazeer, W; Malik, W; Qayyum, A; Hanif, K; Mahmood, A; Islam, N

    2011-10-07

    Cotton is under the constant threat of leaf curl virus, which is a major constraint for successful production of cotton in the Pakistan. A total of 3338 cotton genotypes belonging to different research stations were screened, but none were found to be resistant against the Burewala strain of cotton leaf curl virus (CLCuV). We explored the possibility of transferring virus-resistant genes from Gossypium arboreum (2n = 26) into G. hirsutum (2n = 52) through conventional breeding techniques. Hybridization was done manually between an artificial autotetraploid of G. arboreum and an allotetraploid G. hirsutum, under field conditions. Boll shedding was controlled by application of exogenous hormones, 50 mg/L gibberellic acid and 100 mg/L naphthalene acetic acid. Percentage pollen viability in F(1) hybrids was 1.90% in 2(G. arboreum) x G. hirsutum and 2.38% in G. hirsutum x G. arboreum. Cytological studies of young buds taken from the F(1) hybrids confirmed that they all were sterile. Resistance against CLCuV in the F(1) hybrids was assessed through grafting, using the hybrid plant as the scion; the stock was a virus susceptible cotton plant, tested under field and greenhouse conditions. All F(1) cotton hybrids showed resistance against CLCuV, indicating that it is possible to transfer resistant genes from the autotetraploid of the diploid donor specie G. arboreum into allotetraploid G. hirsutum through conventional breeding, and durable resistance against CLCuV can then be deployed in the field.

  11. Amplicon based RNA interference targeting V2 gene of cotton leaf curl Kokhran virus-Burewala strain can provide resistance in transgenic cotton plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An RNAi based gene construct designated “C2” was used to target the V2 region of the cotton leaf curl virus (CLCuV) genome which is responsible for virus movement. The construct was transformed into two elite cotton varieties MNH-786 and VH-289. A shoot apex method of plant transformation using Agr...

  12. Isothermal rolling circle amplification of virus genomes for rapid antigen detection and typing.

    PubMed

    Brasino, Michael D; Cha, Jennifer N

    2015-08-01

    In this work, isothermal rolling circle amplification (RCA) of the multi-kilobase genome of engineered filamentous bacteriophage is used to report the presence and identification of specific protein analytes in solution. First, bacteriophages were chosen as sensing platforms because peptides or antibodies that bind medically relevant targets can be isolated through phage display or expressed as fusions to their p3 and p8 coat proteins. Second, the circular, single-stranded genome contained within the phage serves as a natural large DNA template for a RCA reaction to rapidly generate exponential amounts of double stranded DNA in a single isothermal step that can be easily detected using low-cost fluorescent nucleic acid stains. Amplifying the entire phage genome also provides high detection sensitivities. Furthermore, since the sequence of the viral DNA can be easily modified with multiple restriction enzyme sites, a simple DNA digest can be applied to detect and identify multiple antigens simultaneously. The methods developed here will lead to protein sensors that are highly scalable to produce, can be run without complex biological equipment and do not require the use of multiple antibodies or high-cost fluorescent DNA probes or nucleotides.

  13. A single-tube PCR assay for detecting viruses and their recombinants that cause tomato yellow leaf curl disease in the Mediterranean basin.

    PubMed

    Davino, Salvatore; Davino, Mario; Accotto, Gian Paolo

    2008-01-01

    Tomato yellow leaf curl disease (TYLCD) is well known in Mediterranean countries, where it has been causing severe losses in tomato crops for decades. Until recently, two viruses (with several isolates) in the genus Begomovirus, family Geminiviridae, have been associated with the epidemics: Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV). However, recombinants between these, such as Tomato yellow leaf curl Malaga virus (TYLCMalV), are spreading, and new methods for detecting all viruses present in the region are needed. By considering all DNA sequences available of viruses causing TYLCD in the Mediterranean basin, a PCR/RFLP protocol was developed that amplifies the intergenic region in a multiplex reaction, followed by digestion with AclI (=Psp1406I) restriction enzyme. This procedure generates an easily recognizable pattern on gels, with DNA fragments of specific size for each virus species and each recombinant: 800 bp for TYLCSV, 410 bp for TYLCV, 570 bp for TYLCMalV and the other detected recombinants, 640 bp for hypothetical recombinants of different type. This new method gives, with a single reaction, an overview of the species present in the sample and will be useful for screening the causal agents of TYLCD, as well as in breeding programs for resistance. PMID:17868911

  14. Recruitment of the host plant heat shock protein 70 by Tomato yellow leaf curl virus coat protein is required for virus infection.

    PubMed

    Gorovits, Rena; Moshe, Adi; Ghanim, Murad; Czosnek, Henryk

    2013-01-01

    A functional capsid protein (CP) is essential for host plant infection and insect transmission of Tomato yellow leaf curl virus (TYLCV) and other monopartite begomoviruses. We have previously shown that TYLCV CP specifically interacts with the heat shock protein 70 (HSP70) of the virus insect vector, Bemisia tabaci. Here we demonstrate that during the development of tomato plant infection with TYLCV, a significant amount of HSP70 shifts from a soluble form into insoluble aggregates. CP and HSP70 co-localize in these aggregates, first in the cytoplasm, then in the nucleus of cells associated with the vascular system. CP-HSP70 interaction was demonstrated by co-immunopreciptation in cytoplasmic - but not in nuclear extracts from leaf and stem. Inhibition of HSP70 expression by quercetin caused a decrease in the amount of nuclear CP aggregates and a re-localization of a GFP-CP fusion protein from the nucleus to the cytoplasm. HSP70 inactivation resulted in a decrease of TYLCV DNA levels, demonstrating the role of HSP70 in TYLCV multiplication in planta. The current study reveals for the first time the involvement of plant HSP70 in TYLCV CP intracellular movement. As described earlier, nuclear aggregates contained TYLCV DNA-CP complexes and infectious virions. Showing that HSP70 localizes in these large nuclear aggregates infers that these structures operate as nuclear virus factories.

  15. Recruitment of the Host Plant Heat Shock Protein 70 by Tomato Yellow Leaf Curl Virus Coat Protein Is Required for Virus Infection

    PubMed Central

    Gorovits, Rena; Moshe, Adi; Ghanim, Murad; Czosnek, Henryk

    2013-01-01

    A functional capsid protein (CP) is essential for host plant infection and insect transmission of Tomato yellow leaf curl virus (TYLCV) and other monopartite begomoviruses. We have previously shown that TYLCV CP specifically interacts with the heat shock protein 70 (HSP70) of the virus insect vector, Bemisia tabaci. Here we demonstrate that during the development of tomato plant infection with TYLCV, a significant amount of HSP70 shifts from a soluble form into insoluble aggregates. CP and HSP70 co-localize in these aggregates, first in the cytoplasm, then in the nucleus of cells associated with the vascular system. CP-HSP70 interaction was demonstrated by co-immunopreciptation in cytoplasmic - but not in nuclear extracts from leaf and stem. Inhibition of HSP70 expression by quercetin caused a decrease in the amount of nuclear CP aggregates and a re-localization of a GFP-CP fusion protein from the nucleus to the cytoplasm. HSP70 inactivation resulted in a decrease of TYLCV DNA levels, demonstrating the role of HSP70 in TYLCV multiplication in planta. The current study reveals for the first time the involvement of plant HSP70 in TYLCV CP intracellular movement. As described earlier, nuclear aggregates contained TYLCV DNA-CP complexes and infectious virions. Showing that HSP70 localizes in these large nuclear aggregates infers that these structures operate as nuclear virus factories. PMID:23894631

  16. Recruitment of the host plant heat shock protein 70 by Tomato yellow leaf curl virus coat protein is required for virus infection.

    PubMed

    Gorovits, Rena; Moshe, Adi; Ghanim, Murad; Czosnek, Henryk

    2013-01-01

    A functional capsid protein (CP) is essential for host plant infection and insect transmission of Tomato yellow leaf curl virus (TYLCV) and other monopartite begomoviruses. We have previously shown that TYLCV CP specifically interacts with the heat shock protein 70 (HSP70) of the virus insect vector, Bemisia tabaci. Here we demonstrate that during the development of tomato plant infection with TYLCV, a significant amount of HSP70 shifts from a soluble form into insoluble aggregates. CP and HSP70 co-localize in these aggregates, first in the cytoplasm, then in the nucleus of cells associated with the vascular system. CP-HSP70 interaction was demonstrated by co-immunopreciptation in cytoplasmic - but not in nuclear extracts from leaf and stem. Inhibition of HSP70 expression by quercetin caused a decrease in the amount of nuclear CP aggregates and a re-localization of a GFP-CP fusion protein from the nucleus to the cytoplasm. HSP70 inactivation resulted in a decrease of TYLCV DNA levels, demonstrating the role of HSP70 in TYLCV multiplication in planta. The current study reveals for the first time the involvement of plant HSP70 in TYLCV CP intracellular movement. As described earlier, nuclear aggregates contained TYLCV DNA-CP complexes and infectious virions. Showing that HSP70 localizes in these large nuclear aggregates infers that these structures operate as nuclear virus factories. PMID:23894631

  17. New Insecticides for Management of Tomato Yellow Leaf Curl, a Virus Vectored by the Silverleaf Whitefly, Bemisia tabaci

    PubMed Central

    Smith, H. A.; Giurcanu, M. C.

    2014-01-01

    Greenhouse studies using a randomized complete block design were carried out to evaluate the effect of six insecticides on transmission of Tomato yellow leaf curl virus (TYLCV) by the silverleaf whitefly, Bemisia tabaci biotype B Gennadius (Hemiptera: Aleyrodidae) to tomato, Lycopersicon esculentum (Miller) (Solanales: Solanaceae), seedlings that were inoculated with whiteflies from a TYLCV colony in cages 3, 7, or 14 d after treatment with insecticide. The purpose was to reveal differences in residual efficacy of four materials that are nearing registration for use on tomato—cyazypyr, flupyradifurone, pyrafluquinazon, and sulfoxaflor—and to compare them with two established insecticides, pymetrozine and a zeta-cypermethrin/bifenthrin combination. Differences in efficacy were expected because these six materials represent five distinct modes of action and both contact and systemic materials. Percentage of tomato seedlings expressing virus symptoms tended to be lowest in seedlings treated with flupyradifurone. The zeta-cypermethrin/bifenthrin insecticide demonstrated comparable efficacy to flupyradifurone in some trials at 3 and 7 d after treatment inoculations, but not the 14 d after treatment inoculation. Pyrafluquinazon was not statistically different from cyazypyr or sulfoxaflor in percentage of plants with virus symptoms in any trial. Percentage virus in the cyazypyr and sulfoxaflor treatments was not statistically different in the 3 and 7 d after treatment inoculations. Among seedlings treated with insecticide, percentage with virus symptoms tended to be highest in the seedlings treated with pymetrozine. PMID:25368089

  18. Tomato Yellow Leaf Curl Virus Benefits Population Growth of the Q Biotype of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae).

    PubMed

    Maluta, N K P; Garzo, E; Moreno, A; Lopes, J R S; Fereres, A

    2014-08-01

    Plant viruses can directly influence their insect vectors, and indirectly through their shared host plant, altering their behavior and performance in a mutualistic or rather antagonistic manner. One of the most studied begomovirus, Tomato yellow leaf curl virus (TYLCV), may also facilitate the expansion of its vector, the whitefly Bemisia tabaci (Gennadius). Considering the likely expansion of the disease and its major vector, we studied the direct and the indirect effects of a Mediterranean isolate of this virus (TYLCV-IL) on the biological performance of the Q biotype of B. tabaci. The following parameters were examined: development time and viability of nymphs, sex ratio, fecundity, and fertility and longevity. The results varied from positive to neutral depending on the parameter and the effect studied. TYLCV accelerated nymphal developmental and increased male longevity of B. tabaci when viruliferous insects developed on TYLCV-immune eggplants (direct effects). An indirect, positive effect of TYLCV-infected plants was observed on fecundity of B. tabaci, which laid more eggs on virus-infected than on noninfected tomato plants. Our results show that TYLCV enhances the population increase of its whitefly vector and that there is a high risk of rapid expansion of both the virus and its vector-the MED species of B. tabaci-into new areas when both agents interact together. PMID:27193818

  19. New insecticides for management of tomato yellow leaf curl, a virus vectored by the silverleaf whitefly, Bemisia tabaci.

    PubMed

    Smith, H A; Giurcanu, M C

    2014-01-01

    Greenhouse studies using a randomized complete block design were carried out to evaluate the effect of six insecticides on transmission of Tomato yellow leaf curl virus (TYLCV) by the silverleaf whitefly, Bemisia tabaci biotype B Gennadius (Hemiptera: Aleyrodidae) to tomato, Lycopersicon esculentum (Miller) (Solanales: Solanaceae), seedlings that were inoculated with whiteflies from a TYLCV colony in cages 3, 7, or 14 d after treatment with insecticide. The purpose was to reveal differences in residual efficacy of four materials that are nearing registration for use on tomato-cyazypyr, flupyradifurone, pyrafluquinazon, and sulfoxaflor-and to compare them with two established insecticides, pymetrozine and a zeta-cypermethrin/bifenthrin combination. Differences in efficacy were expected because these six materials represent five distinct modes of action and both contact and systemic materials. Percentage of tomato seedlings expressing virus symptoms tended to be lowest in seedlings treated with flupyradifurone. The zeta-cypermethrin/bifenthrin insecticide demonstrated comparable efficacy to flupyradifurone in some trials at 3 and 7 d after treatment inoculations, but not the 14 d after treatment inoculation. Pyrafluquinazon was not statistically different from cyazypyr or sulfoxaflor in percentage of plants with virus symptoms in any trial. Percentage virus in the cyazypyr and sulfoxaflor treatments was not statistically different in the 3 and 7 d after treatment inoculations. Among seedlings treated with insecticide, percentage with virus symptoms tended to be highest in the seedlings treated with pymetrozine. PMID:25368089

  20. Implication of the Bacterial Endosymbiont Rickettsia spp. in Interactions of the Whitefly Bemisia tabaci with Tomato yellow leaf curl virus

    PubMed Central

    Kliot, Adi; Cilia, Michelle; Czosnek, Henryk

    2014-01-01

    ABSTRACT Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. IMPORTANCE Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with

  1. Silencing of ORFs C2 and C4 of Tomato Yellow Leaf Curl Virus Engenders Resistant or Tolerant Plants.

    PubMed

    Peretz, Yuval; Eybishtz, Assaf; Sela, Ilan

    2011-01-01

    The IL-60 system is a transient universal vector system for expression and silencing in plants [1]. This vector has been derived from Tomato yellow leaf curl virus (TYLCV). The viral intergenic region (IR) is a non-coding short (314 b) sequence separating the viral sense-oriented genes from the complementary-oriented genes. IR carries the viral origin of replication as well as a promoter at each end. Placing a gene segment between two IRs at opposite orientations followed by trans-activation of the construct by the plasmid IL-60-BS, caused silencing of the pertinent gene as indicated by the silencing of the endogenous gene PDS.. The viral genes C2 and C4 are implicated as having a role in viral-directed silencing suppression. The silencing of C2 and C4 intervened with the virus ability to counter-react to viral silencing by the host plant, thus engendering resistance or tolerance. PMID:22253651

  2. V2 of tomato yellow leaf curl virus can suppress methylation-mediated transcriptional gene silencing in plants.

    PubMed

    Wang, Bi; Li, Fangfang; Huang, Changjun; Yang, Xiuling; Qian, Yajuan; Xie, Yan; Zhou, Xueping

    2014-01-01

    Tomato yellow leaf curl virus (TYLCV) is a DNA virus belonging to the genus Begomovirus. TYLCV replicates using double-stranded DNA intermediates that can become the target of plant transcriptional gene silencing (TGS). Here, we show that the V2 protein of TYLCV can suppress TGS of a transcriptionally silenced green fluorescent protein (GFP) transgene in Nicotiana benthamiana line 16-TGS. Through bisulfite sequencing and chop-PCR, we demonstrated that the TYLCV V2 can reverse GFP transgene silencing by reducing the methylation levels in the 35S promoter sequence. Both AtSN1 and MEA-ISR loci in Arabidopsis thaliana were previously reported to be strongly methylated, and we show that the methylation status of both loci was significantly reduced in TYLCV V2 transgenic Arabidopsis plants. We conclude that TYLCV can efficiently suppress TGS when it infects plants, and its V2 protein is responsible for the TGS suppression activity. PMID:24187017

  3. Severe outbreak of tomato yellow leaf curl Sardinia virus on pepper in southern Italy.

    PubMed

    Comes, Soccorsa; Fanigliulo, Angela; Pacella, Rosa; Crescenzi, Aniello

    2009-01-01

    During summer and autumn 2008 a severe outbreak of pepper leaf curl disease (PLCD) was observed in pepper crops under plastic tunnels in the ionic coast of Basilicata region. Its incidence reached, in some cases, values close to 50%. The beginning of infections was recorded along the perimeter of the tunnels, where it reached a percentage of almost 100%. The infection then progressively spread towards the central areas of the greenhouses. Large populations of whiteflies, identificated as Bemisia tabaci, were observed on the infected crops. Detection assays for TYLCSV and TYLCV were performed in order to ascertain the etiologic agent: 190 symptomatic samples were collected from different fields and assayed in DAS-ELISA using a broad-spectrum reagent combination (distributed by Bioreba AG) detecting TYLCV, TYLCSV and other Begamoviruses: of these, 176 samples resulted positive. In order to discriminate between TYLCSV, TYLCV or any other Begamovirus, 15 positive samples were analyzed by PCR using a couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene. RFLP analysis performed on the PCR product, 1008 bp long, showed the presence of only TYLCSV in all assayed samples. The molecular characterization performed by phylogenetic analysis of the sequenced coat protein gene revealed that the isolate shares a similarity of about 97% with the corresponding sequence of a tomato TYLCSV isolate from Sicily (Z28390) and is almost identical with the pepper isolate CAB-It recovered in the same area in 2007 (TYLCSV was first recorded on pepper in Italy in 2007 in Policoro-MT, Fanigliulo et al., 2008. Comm. Appl. Biol. Sci, Ghent University, 73/2, 2008), indicating that there is a very low variability in TYLCSV population in the surveyed area. The further diffusion of PLCD and its hazard has to be connected with the presence of wide tomato cultivations, of weed hosts alternative to pepper (Solanum nigrum, Datura stramonium, Sonchus asper

  4. Development of a full-genome cDNA clone of Citrus leaf blotch virus and infection of citrus plants.

    PubMed

    Vives, María Carmen; Martín, Susana; Ambrós, Silvia; Renovell, Agueda; Navarro, Luis; Pina, Jose Antonio; Moreno, Pedro; Guerri, José

    2008-11-01

    Citrus leaf blotch virus (CLBV), a member of the family Flexiviridae, has a ~9-kb single-stranded, positive-sense genomic RNA encapsidated by a 41-kDa coat protein. CLBV isolates are associated with symptom production in citrus including leaf blotching of Dweet tangor and stem pitting in Etrog citron (Dweet mottle disease), and some isolates are associated with bud union crease on trifoliate rootstocks, but Koch's postulates for this virus were not fulfilled. A full-genome cDNA of CLBV isolate SRA-153, which induces bud union crease, was placed under the T7 promoter (clone T7-CLBV), or between the 35S promoter and the Nos-t terminator, with or without a ribozyme sequence downstream of the CLBV sequence (clones 35SRbz-CLBV and 35S-CLBV). RNA transcripts from T7-CLBV failed to infect Etrog citron and Nicotiana occidentalis and N. benthamiana plants, whereas agro-inoculation with binary vectors carrying 35SRbz-CLBV or 35S-CLBV, and the p19 silencing suppressor, caused systemic infection and production of normal CLBV virions. Virus accumulation was similar in citron plants directly agro-infiltrated, or mechanically inoculated with wild-type or 35SRbz-CLBV-derived virions from Nicotiana, and the three sources incited the symptoms characteristic of Dweet mottle disease, but not bud union crease. Our results show that (1) virions derived from an infectious clone show the same replication, movement and pathogenicity characteristics as the wild-type CLBV; (2) CLBV is the causal agent of Dweet mottle disease but not of the bud union crease syndrome; and (3) for the first time an RNA virus could be successfully agro-inoculated on citrus plants. This infectious clone may become a useful viral vector for citrus genomic studies.

  5. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex.

    PubMed

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-01-01

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs.

  6. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex

    PubMed Central

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-01-01

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs. PMID:26486606

  7. Use of Posttranscription Gene Silencing in Squash to Induce Resistance against the Egyptian Isolate of the Squash Leaf Curl Virus.

    PubMed

    Taha, Omnia; Farouk, Inas; Abdallah, Abdelhadi; Abdallah, Naglaa A

    2016-01-01

    Squash leaf curl virus (SqLCV) is a bipartite begomovirus affecting squash plants. It is transmitted by whitefly Bemisia tabaci biotype B causing severe leaf curling, vein banding, and molting ending by stunting. In this study full-length genomic clone of SqLCV Egyptian isolated and posttranscriptional gene silencing (PTGS) has been induced to develop virus resistance. The Noubaria SqLCV has more than 95% homology with Jordon, Israel, Lebanon, Palestine, and Cairo isolates. Two genes fragment from SqLCV introduced in sense and antisense orientations using pFGC5049 vector to be expressed as hairpin RNA. The first fragment was 348 bp from replication associated protein gene (Rep). The second fragment was 879 bp representing the full sequence of the movement protein gene (BC1). Using real-time PCR, a silencing record of 97% has been recorded to Rep/TrAP construct; as a result it has prevented the appearance of viral symptoms in most tested plants up to two months after infection, while construct containing the BC1 gene scored a reduction in the accumulation of viral genome expression as appearing in real-time PCR results 4.6-fold giving a silencing of 79%, which had a positive effect on symptoms development in most tested plants. PMID:27034922

  8. Use of Posttranscription Gene Silencing in Squash to Induce Resistance against the Egyptian Isolate of the Squash Leaf Curl Virus

    PubMed Central

    Taha, Omnia; Farouk, Inas; Abdallah, Abdelhadi

    2016-01-01

    Squash leaf curl virus (SqLCV) is a bipartite begomovirus affecting squash plants. It is transmitted by whitefly Bemisia tabaci biotype B causing severe leaf curling, vein banding, and molting ending by stunting. In this study full-length genomic clone of SqLCV Egyptian isolated and posttranscriptional gene silencing (PTGS) has been induced to develop virus resistance. The Noubaria SqLCV has more than 95% homology with Jordon, Israel, Lebanon, Palestine, and Cairo isolates. Two genes fragment from SqLCV introduced in sense and antisense orientations using pFGC5049 vector to be expressed as hairpin RNA. The first fragment was 348 bp from replication associated protein gene (Rep). The second fragment was 879 bp representing the full sequence of the movement protein gene (BC1). Using real-time PCR, a silencing record of 97% has been recorded to Rep/TrAP construct; as a result it has prevented the appearance of viral symptoms in most tested plants up to two months after infection, while construct containing the BC1 gene scored a reduction in the accumulation of viral genome expression as appearing in real-time PCR results 4.6-fold giving a silencing of 79%, which had a positive effect on symptoms development in most tested plants. PMID:27034922

  9. Water Balance, Hormone Homeostasis, and Sugar Signaling Are All Involved in Tomato Resistance to Tomato Yellow Leaf Curl Virus.

    PubMed

    Sade, Dagan; Sade, Nir; Shriki, Oz; Lerner, Stephen; Gebremedhin, Alem; Karavani, Asaf; Brotman, Yariv; Osorio, Sonia; Fernie, Alisdair R; Willmitzer, Lothar; Czosnek, Henryk; Moshelion, Menachem

    2014-07-01

    Vacuolar water movement is largely controlled by membrane channels called tonoplast-intrinsic aquaporins (TIP-AQPs). Some TIP-AQP genes, such as TIP2;2 and TIP1;1, are up-regulated upon exposure to biotic stress. Moreover, TIP1;1 transcript levels are higher in leaves of a tomato (Solanum lycopersicum) line resistant to Tomato yellow leaf curl virus (TYLCV) than in those of a susceptible line with a similar genetic background. Virus-induced silencing of TIP1;1 in the tomato resistant line and the use of an Arabidopsis (Arabidopsis thaliana) tip1;1 null mutant showed that resistance to TYLCV is severely compromised in the absence of TIP1:1. Constitutive expression of tomato TIP2;2 in transgenic TYLCV-susceptible tomato and Arabidopsis plants was correlated with increased TYLCV resistance, increased transpiration, decreased abscisic acid levels, and increased salicylic acid levels at the early stages of infection. We propose that TIP-AQPs affect the induction of leaf abscisic acid, which leads to increased levels of transpiration and gas exchange, as well as better salicylic acid signaling. PMID:24989233

  10. Tomato yellow leaf curl virus resistance by Ty-1 involves increased cytosine methylation of viral genomes and is compromised by cucumber mosaic virus infection

    PubMed Central

    Butterbach, Patrick; Verlaan, Maarten G.; Dullemans, Annette; Lohuis, Dick; Visser, Richard G. F.; Bai, Yuling; Kormelink, Richard

    2014-01-01

    Tomato yellow leaf curl virus (TYLCV) and related begomoviruses are a major threat to tomato production worldwide and, to protect against these viruses, resistance genes from different wild tomato species are introgressed. Recently, the Ty-1 resistance gene was identified, shown to code for an RNA-dependent RNA polymerase and to be allelic with Ty-3. Here we show that upon TYLCV challenging of resistant lines carrying Ty-1 or Ty-3, low virus titers were detected concomitant with the production of relatively high levels of siRNAs whereas, in contrast, susceptible tomato Moneymaker (MM) revealed higher virus titers but lower amounts of siRNAs. Comparative analysis of the spatial genomic siRNA distribution showed a consistent and subtle enrichment for siRNAs derived from the V1 and C3 genes in Ty-1 and Ty-3. In plants containing Ty-2 resistance the virus was hardly detectable, but the siRNA profile resembled the one observed in TYLCV-challenged susceptible tomato (MM). Furthermore, a relative hypermethylation of the TYLCV V1 promoter region was observed in genomic DNA collected from Ty-1 compared with that from (MM). The resistance conferred by Ty-1 was also effective against the bipartite tomato severe rugose begomovirus, where a similar genome hypermethylation of the V1 promoter region was discerned. However, a mixed infection of TYLCV with cucumber mosaic virus compromised the resistance. The results indicate that Ty-1 confers resistance to geminiviruses by increasing cytosine methylation of viral genomes, suggestive of enhanced transcriptional gene silencing. The mechanism of resistance and its durability toward geminiviruses under natural field conditions is discussed. PMID:25136118

  11. Tomato yellow leaf curl virus resistance by Ty-1 involves increased cytosine methylation of viral genomes and is compromised by cucumber mosaic virus infection.

    PubMed

    Butterbach, Patrick; Verlaan, Maarten G; Dullemans, Annette; Lohuis, Dick; Visser, Richard G F; Bai, Yuling; Kormelink, Richard

    2014-09-01

    Tomato yellow leaf curl virus (TYLCV) and related begomoviruses are a major threat to tomato production worldwide and, to protect against these viruses, resistance genes from different wild tomato species are introgressed. Recently, the Ty-1 resistance gene was identified, shown to code for an RNA-dependent RNA polymerase and to be allelic with Ty-3. Here we show that upon TYLCV challenging of resistant lines carrying Ty-1 or Ty-3, low virus titers were detected concomitant with the production of relatively high levels of siRNAs whereas, in contrast, susceptible tomato Moneymaker (MM) revealed higher virus titers but lower amounts of siRNAs. Comparative analysis of the spatial genomic siRNA distribution showed a consistent and subtle enrichment for siRNAs derived from the V1 and C3 genes in Ty-1 and Ty-3. In plants containing Ty-2 resistance the virus was hardly detectable, but the siRNA profile resembled the one observed in TYLCV-challenged susceptible tomato (MM). Furthermore, a relative hypermethylation of the TYLCV V1 promoter region was observed in genomic DNA collected from Ty-1 compared with that from (MM). The resistance conferred by Ty-1 was also effective against the bipartite tomato severe rugose begomovirus, where a similar genome hypermethylation of the V1 promoter region was discerned. However, a mixed infection of TYLCV with cucumber mosaic virus compromised the resistance. The results indicate that Ty-1 confers resistance to geminiviruses by increasing cytosine methylation of viral genomes, suggestive of enhanced transcriptional gene silencing. The mechanism of resistance and its durability toward geminiviruses under natural field conditions is discussed. PMID:25136118

  12. Cotton Leaf Curl Multan Virus-Derived Viral Small RNAs Can Target Cotton Genes to Promote Viral Infection.

    PubMed

    Wang, Jinyan; Tang, Yafei; Yang, Yuwen; Ma, Na; Ling, Xitie; Kan, Jialiang; He, Zifu; Zhang, Baolong

    2016-01-01

    RNA silencing is a conserved mechanism in plants that targets viruses. Viral small RNAs (vsiRNAs) can be generated from viral double-stranded RNA replicative intermediates within the infected host, or from host RNA-dependent RNA polymerases activity on viral templates. The abundance and profile of vsiRNAs in viral infections have been reported previously. However, the involvement of vsiRNAs during infection of the Geminiviridae family member cotton leaf curl virus (CLCuD), which causes significant economic losses in cotton growing regions, remains largely uncharacterized. Cotton leaf curl Multan virus (CLCuMuV) associated with a betasatellite called Cotton leaf curl Multan betasatellite (CLCuMuB) is a major constraint to cotton production in South Asia and is now established in Southern China. In this study, we obtained the profiles of vsiRNAs from CLCuMV and CLCuMB in infected upland cotton (Gossypium hirsutum) plants by deep sequencing. Our data showed that vsiRNA that were derived almost equally from sense and antisense CLCuD DNA strands accumulated preferentially as 21- and 22-nucleotide (nt) small RNA population and had a cytosine bias at the 5'-terminus. Polarity distribution revealed that vsiRNAs were almost continuously present along the CLCuD genome and hotspots of sense and antisense strands were mainly distributed in the Rep proteins region of CLCuMuV and in the C1 protein of CLCuMuB. In addition, hundreds of host transcripts targeted by vsiRNAs were predicted, many of which encode transcription factors associated with biotic and abiotic stresses. Quantitative real-time polymerase chain reaction analysis of selected potential vsiRNA targets showed that some targets were significantly down-regulated in CLCuD-infected cotton plants. We also verified the potential function of vsiRNA targets that may be involved in CLCuD infection by virus-induced gene silencing (VIGS) and 5'-rapid amplification of cDNA end (5'-RACE). Here, we provide the first report on vsi

  13. Cotton Leaf Curl Multan Virus-Derived Viral Small RNAs Can Target Cotton Genes to Promote Viral Infection

    PubMed Central

    Wang, Jinyan; Tang, Yafei; Yang, Yuwen; Ma, Na; Ling, Xitie; Kan, Jialiang; He, Zifu; Zhang, Baolong

    2016-01-01

    RNA silencing is a conserved mechanism in plants that targets viruses. Viral small RNAs (vsiRNAs) can be generated from viral double-stranded RNA replicative intermediates within the infected host, or from host RNA-dependent RNA polymerases activity on viral templates. The abundance and profile of vsiRNAs in viral infections have been reported previously. However, the involvement of vsiRNAs during infection of the Geminiviridae family member cotton leaf curl virus (CLCuD), which causes significant economic losses in cotton growing regions, remains largely uncharacterized. Cotton leaf curl Multan virus (CLCuMuV) associated with a betasatellite called Cotton leaf curl Multan betasatellite (CLCuMuB) is a major constraint to cotton production in South Asia and is now established in Southern China. In this study, we obtained the profiles of vsiRNAs from CLCuMV and CLCuMB in infected upland cotton (Gossypium hirsutum) plants by deep sequencing. Our data showed that vsiRNA that were derived almost equally from sense and antisense CLCuD DNA strands accumulated preferentially as 21- and 22-nucleotide (nt) small RNA population and had a cytosine bias at the 5′-terminus. Polarity distribution revealed that vsiRNAs were almost continuously present along the CLCuD genome and hotspots of sense and antisense strands were mainly distributed in the Rep proteins region of CLCuMuV and in the C1 protein of CLCuMuB. In addition, hundreds of host transcripts targeted by vsiRNAs were predicted, many of which encode transcription factors associated with biotic and abiotic stresses. Quantitative real-time polymerase chain reaction analysis of selected potential vsiRNA targets showed that some targets were significantly down-regulated in CLCuD-infected cotton plants. We also verified the potential function of vsiRNA targets that may be involved in CLCuD infection by virus-induced gene silencing (VIGS) and 5′-rapid amplification of cDNA end (5′-RACE). Here, we provide the first report

  14. Tomato cultivar tolerant to Tomato leaf curl New Delhi virus infection induces virus-specific short interfering RNA accumulation and defence-associated host gene expression.

    PubMed

    Sahu, Pranav Pankaj; Rai, Neeraj K; Chakraborty, Supriya; Singh, Major; Chandrappa, Prasanna H; Ramesh, Bandarupalli; Chattopadhyay, Debasis; Prasad, Manoj

    2010-07-01

    Tomato leaf curl New Delhi virus (ToLCNDV) infection causes significant yield loss in tomato. The availability of a conventional tolerance source against this virus is limited in tomato. To understand the molecular mechanism of virus tolerance in tomato, the abundance of viral genomic replicative intermediate molecules and virus-directed short interfering RNAs (siRNAs) by the host plant in a naturally tolerant cultivar H-88-78-1 and a susceptible cultivar Punjab Chhuhara at different time points after agroinfection was studied. We report that less abundance of viral replicative intermediate in the tolerant cultivar may have a correlation with a relatively higher accumulation of virus-specific siRNAs. To study defence-related host gene expression in response to ToLCNDV infection, the suppression subtractive hybridization technique was used. A library was prepared from tolerant cultivar H-88-78-1 between ToLCNDV-inoculated and Agrobacterium mock-inoculated plants of this cultivar at 21 days post-inoculation (dpi). A total of 106 nonredundant transcripts was identified and classified into 12 different categories according to their putative functions. By reverse Northern analysis and quantitative real-time polymerase chain reaction (qRT-PCR), we identified the differential expression pattern of 106 transcripts, 34 of which were up-regulated (>2.5-fold induction). Of these, eight transcripts showed more than four fold induction. qRT-PCR analysis was carried out to obtain comparative expression profiling of these eight transcripts between Punjab Chhuhara and H-88-78-1 on ToLCNDV infection. The expression patterns of these transcripts showed a significant increase in differential expression in the tolerant cultivar, mostly at 14 and 21 dpi, in comparison with that in the susceptible cultivar, as analysed by qRT-PCR. The probable direct and indirect relationship of siRNA accumulation and up-regulated transcripts with the ToLCNDV tolerance mechanism is discussed. PMID

  15. The P0 gene of Sugarcane yellow leaf virus encodes an RNA silencing suppressor with unique activities

    SciTech Connect

    Mangwende, Tichaona Wang Mingli Borth, Wayne Hu, John Moore, Paul H. Mirkov, T. Erik Albert, Henrik H.

    2009-02-05

    The Sugarcane yellow leaf virus (SCYLV) P0, a member of the highly heterologous proteins of poleroviruses, is a suppressor of posttranscriptional gene silencing (PTGS) and has additional activities not seen in other P0 proteins. The P0 protein in previously tested poleroviruses (Beet western yellows virus and Cucurbit aphid-borne yellows virus), suppresses local, but not systemic, PTGS induced by both sense GFP and inverted repeat GF using its F-box-like domain to mediate destabilization of the Argonaute1 protein. We now report that the SCYLV P0 protein not only suppressed local PTGS induced by sense GFP and inverted repeat GF in Nicotiana benthamiana, but also triggered a dosage dependent cell death phenotype in infiltrated leaves and suppressed systemic sense GFP-PTGS. Deletion of the first 15 N-terminal amino acid residues of SCYLV P0 abolished suppression of both local and systemic PTGS and the induction of cell death. In contrast, only systemic PTGS and cell death were lost when the 15 C-terminal amino acid residues were deleted. We conclude that the 15 C-terminal amino acid residue region of SCYLV P0 is necessary for suppressing systemic PTGS and inducing cell death, but is not required for suppression of local PTGS.

  16. Genomic analyses of cherry rusty mottle group and cherry twisted leaf-associated viruses reveal a possible new genus within the family betaflexiviridae.

    PubMed

    Villamor, D E V; Susaimuthu, J; Eastwell, K C

    2015-03-01

    It is demonstrated that closely related viruses within the family Betaflexiviridae are associated with a number of diseases that affect sweet cherry (Prunus avium) and other Prunus spp. Cherry rusty mottle-associated virus (CRMaV) is correlated with the appearance of cherry rusty mottle disease (CRMD), and Cherry twisted leaf-associated virus (CTLaV) is linked to cherry twisted leaf disease (CTLD) and apricot ringpox disease (ARPD). Comprehensive analysis of previously reported full genomic sequences plus those determined in this study representing isolates of CTLaV, CRMaV, Cherry green ring mottle virus, and Cherry necrotic rusty mottle virus revealed segregation of sequences into four clades corresponding to distinct virus species. High-throughput sequencing of RNA from representative source trees for CRMD, CTLD, and ARPD did not reveal additional unique virus sequences that might be associated with these diseases, thereby further substantiating the association of CRMaV and CTLaV with CRMD and CTLD or ARPD, respectively. Based on comparison of the nucleotide and amino acid sequence identity values, phylogenetic relationships with other triple-gene block-coding viruses within the family Betaflexiviridae, genome organization, and natural host range, a new genus (Robigovirus) is suggested. PMID:25496302

  17. A begomovirus associated with Ageratum yellow vein disease in Indonesia: evidence for natural recombination between tomato leaf curl Java virus and Ageratum yellow vein virus-[Java].

    PubMed

    Kon, T; Kuwabara, K; Hidayat, S H; Ikegami, M

    2007-01-01

    A begomovirus (2747 nucleotides) and a satellite DNA beta component (1360 nucleotides) have been isolated from Ageratum conyzoides L. plants with yellow vein symptoms growing in Java, Indonesia. The begomovirus is most closely related to Tomato leaf curl Java virus (ToLCJV) (91 and 98% in the total nucleotide and coat protein amino acid sequences, respectively), although the products of ORFs C1 and C4 are more closely related to those of Ageratum yellow vein virus-[Java] (91 and 95% identity, respectively). For this reason, the begomovirus it is considered to be a strain of ToLCJV and is referred to as ToLCJV-Ageratum. The virus probably derives from a recombination event in which nucleotides 2389-2692 of ToLCJV have been replaced with the corresponding region of the AYVV-[Java] genome, which includes the 5' part of the intergenic region and the C1 and C4 ORFs. Infection of A. conyzoides with ToLCJV-Ageratum alone produced no symptoms, but co-infection with DNAbeta induced yellow vein symptoms. Symptoms induced in Nicotiana benthamiana by ToLCJV-Ageratum, ToLCJV and AYVV-[Java] are consistent with the exchange of pathogenicity determinant ORF C4 during recombination.

  18. Transcriptome profiling to discover defense-related genes associated with resistance line ty-5 against Tomato yellow leaf curl virus in tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato yellow leaf curl virus (TYLCV), a whitefly-transmitted begomovirus, has caused serious economic losses to tomato crops in the U.S. and around the world. The most effective management would be the use of a TYLCV-resistant tomato cultivar. Several sources of TYLCV resistance genes have been ide...

  19. Microarray analyses for identifying genes conferring resistance to pepper leaf curl virus in chilli pepper (Capsicum spp.).

    PubMed

    Rai, Ved Prakash; Rai, Ashutosh; Kumar, Rajesh; Kumar, Sanjay; Kumar, Sanjeet; Singh, Major; Singh, Sheo Pratap

    2016-09-01

    Pepper leaf curl virus (PepLCV) is a serious threat to pepper (Capsicum spp.) production worldwide. Molecular mechanism underlying pepper plants response to PepLCV infection is key to develop PepLCV resistant varieties. In this study, we generated transcriptome profiles of PepLCV resistant genotype (BS-35) and susceptible genotype (IVPBC-535) after artificial viral inoculation using microarray technology and detail experimental procedures and analyses are described. A total of 319 genes differentially expressed between resistant and susceptible genotypes were identified, out of that 234 unique genes were found to be up-regulated > 2-fold in resistant line BS-35 when compared to susceptible, IVPBC-535. The data set we generated has been analyzed to identify genes that are involved in the regulation of resistance against PepLCV. The raw data have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE41131.

  20. Microarray analyses for identifying genes conferring resistance to pepper leaf curl virus in chilli pepper (Capsicum spp.).

    PubMed

    Rai, Ved Prakash; Rai, Ashutosh; Kumar, Rajesh; Kumar, Sanjay; Kumar, Sanjeet; Singh, Major; Singh, Sheo Pratap

    2016-09-01

    Pepper leaf curl virus (PepLCV) is a serious threat to pepper (Capsicum spp.) production worldwide. Molecular mechanism underlying pepper plants response to PepLCV infection is key to develop PepLCV resistant varieties. In this study, we generated transcriptome profiles of PepLCV resistant genotype (BS-35) and susceptible genotype (IVPBC-535) after artificial viral inoculation using microarray technology and detail experimental procedures and analyses are described. A total of 319 genes differentially expressed between resistant and susceptible genotypes were identified, out of that 234 unique genes were found to be up-regulated > 2-fold in resistant line BS-35 when compared to susceptible, IVPBC-535. The data set we generated has been analyzed to identify genes that are involved in the regulation of resistance against PepLCV. The raw data have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE41131. PMID:27556012

  1. Molecular dissection of Tomato leaf curl virus resistance in tomato line TY172 derived from Solanum peruvianum.

    PubMed

    Anbinder, Ilana; Reuveni, Moshe; Azari, Raviv; Paran, Ilan; Nahon, Sahadia; Shlomo, Haviva; Chen, Lea; Lapidot, Moshe; Levin, Ilan

    2009-08-01

    Tomato yellow leaf curl virus (TYLCV) is devastating to tomato (Solanum lycopersicum) crops and resistant cultivars are highly effective in controlling the disease. The breeding line TY172, originating from Solanum peruvianum, is highly resistant to TYLCV. To map quantitative trait loci (QTLs) controlling TYLCV resistance in TY172, appropriate segregating populations were analyzed using 69 polymorphic DNA markers spanning the entire tomato genome. Results show that TYLCV resistance in TY172 is controlled by a previously unknown major QTL, originating from the resistant line, and four additional minor QTLs. The major QTL, we term Ty-5, maps to chromosome 4 and accounts for 39.7-46.6% of the variation in symptom severity among segregating plants (LOD score 33-35). The minor QTLs, originated either from the resistant or susceptible parents, were mapped to chromosomes 1, 7, 9 and 11, and contributed 12% to the variation in symptom severity in addition to Ty-5. PMID:19455299

  2. TaqMan real-time PCR for detection and quantitation of squash leaf curl virus in cucurbits.

    PubMed

    Kuan, Cheng-Ping; Huang, Hung-Chang; Chang, Chia-Che; Lu, Yi-Lin

    2012-02-01

    A real-time PCR assay based on the TaqMan chemistry was developed for reliable detection and quantitation of the squash leaf curl virus (SLCV) in melon and squash plants. This method was highly specific to SLCV and it was about one thousand times more sensitive than the conventional PCR method. The protocol of the real-time PCR established in this study enabled detection of as little as 10(2) copies of SLCV DNA with CP gene as the target. This TaqMan real-time PCR assay for detection and quantitation of SLCV would be a useful tool for application in quarantine and certification of SLCV in cucurbits as well as in the research of disease resistance and epidemiology.

  3. Association of tomato leaf curl New Delhi virus DNA-B with bhendi yellow vein mosaic virus in okra showing yellow vein mosaic disease symptoms.

    PubMed

    Venkataravanappa, V; Lakshminarayana Reddy, C N; Jalali, S; Krishna Reddy, M

    2015-06-01

    Okra samples showing yellow vein mosaic, vein twisting and bushy appearance were collected from different locations of India during the surveys conducted between years 2005-2009. The dot blot and PCR detection revealed that 75.14% of the samples were associated with monopartite begomovirus and remaining samples with bipartite virus. Whitefly transmission was established for three samples representing widely separated geographical locations which are negative to betasatellites and associated with DNA-B. Genome components of these three representative isolates were cloned and sequenced. The analysis of DNA-A-like sequence revealed that three begomovirus isolates shared more than 93% nucleotide sequence identity with bhendi yellow vein mosaic virus from India (BYVMV), a monopartite begomovirus species that was reported previously as causative agent of bhendi yellow mosaic disease in association of bhendi yellow vein mosaic betasatellite. Further, the DNA-B-like sequences associated with the three virus isolates shared no more than 90% sequence identity with tomato leaf curl New Delhi virus (ToLCNDV). Analyses of putative iteron-binding sequence required for trans-replication suggests that begomovirus sequences shared compatible rep-binding iterons with DNA-B of ToLCNDV. Our data suggest that the monopartite begomovirus associated with okra yellow vein disease has captured DNA-B of ToLCNDV to infect okra. Widespread distribution of the complex shows the increasing trend of the capturing of DNA-B of ToLCNDV by monopartite begomoviruses in the Indian subcontinent. The recombination analysis showed that the DNA-A might have been derived from the inter-specific recombination of begomoviruses, while DNA-B was derived from the ToLCNDV infecting different hosts.

  4. Silencing of a single gene in tomato plants resistant to Tomato yellow leaf curl virus renders them susceptible to the virus.

    PubMed

    Eybishtz, Assaf; Peretz, Yuval; Sade, Dagan; Akad, Fouad; Czosnek, Henryk

    2009-09-01

    A reverse-genetics approach was applied to identify genes involved in Tomato yellow leaf curl virus (TYLCV) resistance, taking advantage of two tomato inbred lines from the same breeding program-one susceptible (S), one resistant (R-that used Solanum habrochaites as the source of resistance. cDNA libraries from inoculated and non-inoculated R and S plants were compared, postulating that genes preferentially expressed in the R line may be part of the network sustaining resistance to TYLCV. Further, we assumed that silencing genes located at important nodes of the network would lead to collapse of resistance. Approximately 70 different cDNAs representing genes preferentially expressed in R plants were isolated and their genes identified by comparison with public databases. A Permease I-like protein gene encoding a transmembranal transporter was further studied: it was preferentially expressed in R plants and its expression was enhanced several-fold following TYLCV inoculation. Silencing of the Permease gene of R plants using Tobacco rattle virus-induced gene silencing led to loss of resistance, expressed as development of disease symptoms typical of infected susceptible plants and accumulation of large amounts of virus. Silencing of another membrane protein gene preferentially expressed in R plants, Pectin methylesterase, previously shown to be involved in Tobacco mosaic virus translocation, did not lead to collapse of resistance of R plants. Thus, silencing of a single gene can lead to collapse of resistance, but not every gene preferentially expressed in the R line has the same effect, upon silencing, on resistance. PMID:19533378

  5. Association of tomato leaf curl New Delhi virus DNA-B with bhendi yellow vein mosaic virus in okra showing yellow vein mosaic disease symptoms.

    PubMed

    Venkataravanappa, V; Lakshminarayana Reddy, C N; Jalali, S; Krishna Reddy, M

    2015-06-01

    Okra samples showing yellow vein mosaic, vein twisting and bushy appearance were collected from different locations of India during the surveys conducted between years 2005-2009. The dot blot and PCR detection revealed that 75.14% of the samples were associated with monopartite begomovirus and remaining samples with bipartite virus. Whitefly transmission was established for three samples representing widely separated geographical locations which are negative to betasatellites and associated with DNA-B. Genome components of these three representative isolates were cloned and sequenced. The analysis of DNA-A-like sequence revealed that three begomovirus isolates shared more than 93% nucleotide sequence identity with bhendi yellow vein mosaic virus from India (BYVMV), a monopartite begomovirus species that was reported previously as causative agent of bhendi yellow mosaic disease in association of bhendi yellow vein mosaic betasatellite. Further, the DNA-B-like sequences associated with the three virus isolates shared no more than 90% sequence identity with tomato leaf curl New Delhi virus (ToLCNDV). Analyses of putative iteron-binding sequence required for trans-replication suggests that begomovirus sequences shared compatible rep-binding iterons with DNA-B of ToLCNDV. Our data suggest that the monopartite begomovirus associated with okra yellow vein disease has captured DNA-B of ToLCNDV to infect okra. Widespread distribution of the complex shows the increasing trend of the capturing of DNA-B of ToLCNDV by monopartite begomoviruses in the Indian subcontinent. The recombination analysis showed that the DNA-A might have been derived from the inter-specific recombination of begomoviruses, while DNA-B was derived from the ToLCNDV infecting different hosts. PMID:26104329

  6. Genetic diversity and distribution of a distinct strain of Chili leaf curl virus and associated betasatellite infecting tomato and pepper in Oman.

    PubMed

    Khan, Akhtar J; Akhtar, Sohail; Al-Zaidi, Amal M; Singh, Achuit K; Briddon, Rob W

    2013-10-01

    Tomato and pepper are widely grown in Oman for local consumption. A countrywide survey was conducted during 2010-2011 to collect samples and assess the diversity of begomoviruses associated with leaf curl disease of tomato and pepper. A virus previously only identified on the Indian subcontinent, chili leaf curl virus (ChLCV), was found associated with tomato and pepper diseases in all vegetable grown areas of Oman. Some of the infected plant samples were also found to contain a betasatellite. A total of 19 potentially full-length begomovirus and eight betasatellite clones were sequenced. The begomovirus clones showed >96% nucleotide sequence identity, showing them to represent a single species. Comparisons to sequences available in the databases showed the highest levels of nucleotide sequence identity (88.0-91.1%) to isolates of the "Pakistan" strain of ChLCV (ChLCV-PK), indicating the virus from Oman to be a distinct strain, for which the name Oman strain (ChLCV-OM) is proposed. An analysis for recombination showed ChLCV-OM likely to have originated by recombination between ChLCV-PK (the major parent), pepper leaf curl Lahore virus and a third strain of ChLCV. The betasatellite sequences obtained were shown to have high levels of identity to isolates of tomato leaf curl betasatellite (ToLCB) previous shown to be present in Oman. For the disease in tomato Koch's postulates were satisfied by Agrobacterium-mediated inoculation of virus and betasatellites clones. This showed the symptoms induced by the virus in the presence of the betasatellite to be enhanced, although viral DNA levels were not affected. ChLCV-OM is the fourth begomovirus identified in tomato in Oman and the first in Capsicum. The significance of these findings is discussed.

  7. Genetic diversity and distribution of a distinct strain of Chili leaf curl virus and associated betasatellite infecting tomato and pepper in Oman.

    PubMed

    Khan, Akhtar J; Akhtar, Sohail; Al-Zaidi, Amal M; Singh, Achuit K; Briddon, Rob W

    2013-10-01

    Tomato and pepper are widely grown in Oman for local consumption. A countrywide survey was conducted during 2010-2011 to collect samples and assess the diversity of begomoviruses associated with leaf curl disease of tomato and pepper. A virus previously only identified on the Indian subcontinent, chili leaf curl virus (ChLCV), was found associated with tomato and pepper diseases in all vegetable grown areas of Oman. Some of the infected plant samples were also found to contain a betasatellite. A total of 19 potentially full-length begomovirus and eight betasatellite clones were sequenced. The begomovirus clones showed >96% nucleotide sequence identity, showing them to represent a single species. Comparisons to sequences available in the databases showed the highest levels of nucleotide sequence identity (88.0-91.1%) to isolates of the "Pakistan" strain of ChLCV (ChLCV-PK), indicating the virus from Oman to be a distinct strain, for which the name Oman strain (ChLCV-OM) is proposed. An analysis for recombination showed ChLCV-OM likely to have originated by recombination between ChLCV-PK (the major parent), pepper leaf curl Lahore virus and a third strain of ChLCV. The betasatellite sequences obtained were shown to have high levels of identity to isolates of tomato leaf curl betasatellite (ToLCB) previous shown to be present in Oman. For the disease in tomato Koch's postulates were satisfied by Agrobacterium-mediated inoculation of virus and betasatellites clones. This showed the symptoms induced by the virus in the presence of the betasatellite to be enhanced, although viral DNA levels were not affected. ChLCV-OM is the fourth begomovirus identified in tomato in Oman and the first in Capsicum. The significance of these findings is discussed. PMID:23911631

  8. Development and validation of a multiplex reverse transcription quantitative PCR (RT-qPCR) assay for the rapid detection of Citrus tristeza virus, Citrus psorosis virus, and Citrus leaf blotch virus.

    PubMed

    Osman, Fatima; Hodzic, Emir; Kwon, Sun-Jung; Wang, Jinbo; Vidalakis, Georgios

    2015-08-01

    A single real-time multiplex reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay for the simultaneous detection of Citrus tristeza virus (CTV), Citrus psorosis virus (CPsV), and Citrus leaf blotch virus (CLBV) was developed and validated using three different fluorescently labeled minor groove binding qPCR probes. To increase the detection reliability, coat protein (CP) genes from large number of different isolates of CTV, CPsV and CLBV were sequenced and a multiple sequence alignment was generated with corresponding CP sequences from the GenBank and a robust multiplex RT-qPCR assay was designed. The capacity of the multiplex RT-qPCR assay in detecting the viruses was compared to singleplex RT-qPCR designed specifically for each virus and was assessed using multiple virus isolates from diverse geographical regions and citrus species as well as graft-inoculated citrus plants infected with various combination of the three viruses. No significant difference in detection limits was found and specificity was not affected by the inclusion of the three assays in a multiplex RT-qPCR reaction. Comparison of the viral load for each virus using singleplex and multiplex RT-qPCR assays, revealed no significant differences between the two assays in virus detection. No significant difference in Cq values was detected when using one-step and two-step multiplex RT-qPCR detection formats. Optimizing the RNA extraction technique for citrus tissues and testing the quality of the extracted RNA using RT-qPCR targeting the cytochrome oxidase citrus gene as an RNA specific internal control proved to generate better diagnostic assays. Results showed that the developed multiplex RT-qPCR can streamline viruses testing of citrus nursery stock by replacing three separate singleplex assays, thus reducing time and labor while retaining the same sensitivity and specificity. The three targeted RNA viruses are regulated pathogens for California's mandatory "Section 3701

  9. Development and validation of a multiplex reverse transcription quantitative PCR (RT-qPCR) assay for the rapid detection of Citrus tristeza virus, Citrus psorosis virus, and Citrus leaf blotch virus.

    PubMed

    Osman, Fatima; Hodzic, Emir; Kwon, Sun-Jung; Wang, Jinbo; Vidalakis, Georgios

    2015-08-01

    A single real-time multiplex reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay for the simultaneous detection of Citrus tristeza virus (CTV), Citrus psorosis virus (CPsV), and Citrus leaf blotch virus (CLBV) was developed and validated using three different fluorescently labeled minor groove binding qPCR probes. To increase the detection reliability, coat protein (CP) genes from large number of different isolates of CTV, CPsV and CLBV were sequenced and a multiple sequence alignment was generated with corresponding CP sequences from the GenBank and a robust multiplex RT-qPCR assay was designed. The capacity of the multiplex RT-qPCR assay in detecting the viruses was compared to singleplex RT-qPCR designed specifically for each virus and was assessed using multiple virus isolates from diverse geographical regions and citrus species as well as graft-inoculated citrus plants infected with various combination of the three viruses. No significant difference in detection limits was found and specificity was not affected by the inclusion of the three assays in a multiplex RT-qPCR reaction. Comparison of the viral load for each virus using singleplex and multiplex RT-qPCR assays, revealed no significant differences between the two assays in virus detection. No significant difference in Cq values was detected when using one-step and two-step multiplex RT-qPCR detection formats. Optimizing the RNA extraction technique for citrus tissues and testing the quality of the extracted RNA using RT-qPCR targeting the cytochrome oxidase citrus gene as an RNA specific internal control proved to generate better diagnostic assays. Results showed that the developed multiplex RT-qPCR can streamline viruses testing of citrus nursery stock by replacing three separate singleplex assays, thus reducing time and labor while retaining the same sensitivity and specificity. The three targeted RNA viruses are regulated pathogens for California's mandatory "Section 3701

  10. Rapid accumulation and low degradation: key parameters of Tomato yellow leaf curl virus persistence in its insect vector Bemisia tabaci

    PubMed Central

    Becker, Nathalie; Rimbaud, Loup; Chiroleu, Frédéric; Reynaud, Bernard; Thébaud, Gaël; Lett, Jean-Michel

    2015-01-01

    Of worldwide economic importance, Tomato yellow leaf curl virus (TYLCV, Begomovirus) is responsible for one of the most devastating plant diseases in warm and temperate regions. The DNA begomoviruses (Geminiviridae) are transmitted by the whitefly species complex Bemisia tabaci. Although geminiviruses have long been described as circulative non-propagative viruses, observations such as long persistence of TYLCV in B. tabaci raised the question of their possible replication in the vector. We monitored two major TYLCV strains, Mild (Mld) and Israel (IL), in the invasive B. tabaci Middle East-Asia Minor 1 cryptic species, during and after the viral acquisition, within two timeframes (0–144 hours or 0–20 days). TYLCV DNA was quantified using real-time PCR, and the complementary DNA strand of TYLCV involved in viral replication was specifically quantified using anchored real-time PCR. The DNA of both TYLCV strains accumulated exponentially during acquisition but remained stable after viral acquisition had stopped. Neither replication nor vertical transmission were observed. In conclusion, our quantification of the viral loads and complementary strands of both Mld and IL strains of TYLCV in B. tabaci point to an efficient accumulation and preservation mechanism, rather than to a dynamic equilibrium between replication and degradation. PMID:26625871

  11. Functional Characterization of a Strong Bi-directional Constitutive Plant Promoter Isolated from Cotton Leaf Curl Burewala Virus

    PubMed Central

    Khan, Zainul A.; Abdin, Malik Z.; Khan, Jawaid A.

    2015-01-01

    Cotton leaf curl Burewala virus (CLCuBuV), belonging to the genus Begomovirus, possesses single-stranded monopartite DNA genome. The bidirectional promoters representing Rep and coat protein (CP) genes of CLCuBuV were characterized and their efficacy was assayed. Rep and CP promoters of CLCuBuV and 35S promoter of Cauliflower mosaic virus (CaMV) were fused with β-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes. GUS activity in individual plant cells driven by Rep, CP and 35S promoters was estimated using real-time PCR and fluorometric GUS assay. Histochemical staining of GUS in transformed tobacco (Nicotiana tabacum cv. Xanthi) leaves showed highest expression driven by Rep promoter followed by 35S promoter and CP promoter. The expression level of GUS driven by Rep promoter in transformed tobacco plants was shown to be two to four-fold higher than that of 35S promoter, while the expression by CP promoter was slightly lower. Further, the expression of GFP was monitored in agroinfiltrated leaves of N. benthamiana, N. tabacum and cotton (Gossypium hirsutum) plants using confocal laser scanning microscopy. Rep promoter showed strong consistent transient expression in tobacco and cotton leaves as compared to 35S promoter. The strong constitutive CLCuBuV Rep promoter developed in this study could be very useful for high level expression of transgenes in a wide variety of plant cells. PMID:25799504

  12. High Genetic Stability of the Begomovirus Tomato yellow leaf curl Sardinia virus in Southern Spain Over an 8-Year Period.

    PubMed

    Sánchez-Campos, S; Díaz, J A; Monci, F; Bejarano, E R; Reina, J; Navas-Castillo, J; Aranda, M A; Moriones, E

    2002-08-01

    ABSTRACT The evolution of the plant single-stranded DNA virus Tomato yellow leaf curl Sardinia virus (TYLCSV) (genus Begomovirus, family Geminiviridae) has been monitored for 8 years after its appearance in southern Spain. Variation within three genomic regions of 166 TYLCSV isolates collected from three locations was assessed by single-strand conformation polymorphism (SSCP) analysis. According to SSCP, the intergenic region (IR) was the most variable. Low genetic diversity was found within the population and geographical or temporal differences were not evident. Nucleotide sequences of specific genomic regions of haplotypes identified by SSCP indicated close relationships among them. Therefore, the Spanish TYLCSV population appears to represent a single, undifferentiated population. The analysis of IR sequences for a subsample of 76 randomly chosen isolates confirmed the limited genetic diversity revealed by the SSCP analysis. A tendency to a lineal increase in diversity over time was observed in Málaga and Almería subpopulations; however, no accumulation of mutations in single isolates was evident. Negative selection to variation seems to operate to conserve certain regions of the genome. Thus, the low genetic diversity found in the studied TYLCSV population might be the result of a founder effect with subsequent selection against less fit variants arising by mutation.

  13. Effects of Isaria fumosorosea on TYLCV (Tomato Yellow Leaf Curl Virus) Accumulation and Transmitting Capacity of Bemisia tabaci

    PubMed Central

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is transmitted by the Bemisia tabaci pest Middle East-Asia Minor 1 (MEAM1) in China. Isaria fumosorosea is a fungal pathogen of B. tabaci. However, the effects of fungal infection on TYLCV expression and transmission by MEAM1 are unclear. In this study, potted tomatoes containing second instar nymphs of MEAM1 were treated with I. fumosorosea IfB01 strain and the relationship between fungal infection in MEAM1 and its TYLCV transmission capacity was investigated. The results indicated that a significantly (p < 0.05) decreased incidence of transmission of TYLCV-infected plants (ITYPs) transmitted by second instar nymphs of MEAM1 infected with fungus. Further, we found a negative correlation between fungal conidial concentrations and eclosion rates of MEAM1, and a positive correlation between ITYPs and eclosion. In addition, when each plant was exposed to three adults treated with fungus, a significantly decreased transmission of TYLCV (TYTE) was observed in the infected group. However, the incidence of TYLCV-carrying MEAM1 adults (ITYAs) was not significantly different in the infected and control groups (p < 0.05). Nevertheless, a significant decrease in viral accumulation using TYLCV AC2 gene as a marker was observed in the fungus-infected MEAM1. In conclusion, the results suggested that I. fumosorosea infection decreases TYLCV accumulation in MEAM1 and subsequently reduces its transmission. Our study provides new insights into the relationship between host plant, plant virus, insect vector, and entomopathogenic fungus. PMID:27716852

  14. Functional characterization of a strong bi-directional constitutive plant promoter isolated from cotton leaf curl Burewala virus.

    PubMed

    Khan, Zainul A; Abdin, Malik Z; Khan, Jawaid A

    2015-01-01

    Cotton leaf curl Burewala virus (CLCuBuV), belonging to the genus Begomovirus, possesses single-stranded monopartite DNA genome. The bidirectional promoters representing Rep and coat protein (CP) genes of CLCuBuV were characterized and their efficacy was assayed. Rep and CP promoters of CLCuBuV and 35S promoter of Cauliflower mosaic virus (CaMV) were fused with β-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes. GUS activity in individual plant cells driven by Rep, CP and 35S promoters was estimated using real-time PCR and fluorometric GUS assay. Histochemical staining of GUS in transformed tobacco (Nicotiana tabacum cv. Xanthi) leaves showed highest expression driven by Rep promoter followed by 35S promoter and CP promoter. The expression level of GUS driven by Rep promoter in transformed tobacco plants was shown to be two to four-fold higher than that of 35S promoter, while the expression by CP promoter was slightly lower. Further, the expression of GFP was monitored in agroinfiltrated leaves of N. benthamiana, N. tabacum and cotton (Gossypium hirsutum) plants using confocal laser scanning microscopy. Rep promoter showed strong consistent transient expression in tobacco and cotton leaves as compared to 35S promoter. The strong constitutive CLCuBuV Rep promoter developed in this study could be very useful for high level expression of transgenes in a wide variety of plant cells.

  15. Development of a Scale for Evaluation of Tomato yellow leaf curl virus Resistance Level in Tomato Plants.

    PubMed

    Lapidot, M; Ben-Joseph, R; Cohen, L; Machbash, Z; Levy, D

    2006-12-01

    ABSTRACT We have developed a scale of differential hosts that enables the determination and comparison of level of resistance to Tomato yellow leaf curl virus (TYLCV) expressed by resistant tomato lines or by individual plants in a segregating population. The scale is composed of seven different homozygous tomato genotypes that exhibit different levels of TYLCV resistance, ranging from fully susceptible to highly resistant. The differential hosts composing the scale were inoculated with TYLCV under greenhouse conditions. Four weeks after inoculation the plants were evaluated for disease symptom severity, and virus DNA titer was determined. The different genotypes were arranged in the scale according to symptom severity score. The different genotypes were then tested under different environmental conditions, inoculated at different ages, and tested in a field experiment assaying TYLCV-induced yield reduction. While the symptom severity score of each individual resistant genotype changed under different environmental conditions, the relative position on the scale did not alter, except for one genotype. Thus, to evaluate disease resistance of a given tomato genotype, the genotype in question should be inoculated alongside the differential hosts composing the scale, and within 4 weeks one can determine the relative level of resistance of the tested genotype. PMID:18943674

  16. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype

    PubMed Central

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  17. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype.

    PubMed

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  18. Rapid accumulation and low degradation: key parameters of Tomato yellow leaf curl virus persistence in its insect vector Bemisia tabaci.

    PubMed

    Becker, Nathalie; Rimbaud, Loup; Chiroleu, Frédéric; Reynaud, Bernard; Thébaud, Gaël; Lett, Jean-Michel

    2015-01-01

    Of worldwide economic importance, Tomato yellow leaf curl virus (TYLCV, Begomovirus) is responsible for one of the most devastating plant diseases in warm and temperate regions. The DNA begomoviruses (Geminiviridae) are transmitted by the whitefly species complex Bemisia tabaci. Although geminiviruses have long been described as circulative non-propagative viruses, observations such as long persistence of TYLCV in B. tabaci raised the question of their possible replication in the vector. We monitored two major TYLCV strains, Mild (Mld) and Israel (IL), in the invasive B. tabaci Middle East-Asia Minor 1 cryptic species, during and after the viral acquisition, within two timeframes (0-144 hours or 0-20 days). TYLCV DNA was quantified using real-time PCR, and the complementary DNA strand of TYLCV involved in viral replication was specifically quantified using anchored real-time PCR. The DNA of both TYLCV strains accumulated exponentially during acquisition but remained stable after viral acquisition had stopped. Neither replication nor vertical transmission were observed. In conclusion, our quantification of the viral loads and complementary strands of both Mld and IL strains of TYLCV in B. tabaci point to an efficient accumulation and preservation mechanism, rather than to a dynamic equilibrium between replication and degradation. PMID:26625871

  19. Tomato plant cell death induced by inhibition of HSP90 is alleviated by Tomato yellow leaf curl virus infection.

    PubMed

    Moshe, Adi; Gorovits, Rena; Liu, Yule; Czosnek, Henryk

    2016-02-01

    To ensure a successful long-term infection cycle, begomoviruses must restrain their destructive effect on host cells and prevent drastic plant responses, at least in the early stages of infection. The monopartite begomovirus Tomato yellow leaf curl virus (TYLCV) does not induce a hypersensitive response and cell death on whitefly-mediated infection of virus-susceptible tomato plants until diseased tomatoes become senescent. The way in which begomoviruses evade plant defences and interfere with cell death pathways is still poorly understood. We show that the chaperone HSP90 (heat shock protein 90) and its co-chaperone SGT1 (suppressor of the G2 allele of Skp1) are involved in the establishment of TYLCV infection. Inactivation of HSP90, as well as silencing of the Hsp90 and Sgt1 genes, leads to the accumulation of damaged ubiquitinated proteins and to a cell death phenotype. These effects are relieved under TYLCV infection. HSP90-dependent inactivation of 26S proteasome degradation and the transcriptional activation of the heat shock transcription factors HsfA2 and HsfB1 and of the downstream genes Hsp17 and Apx1/2 are suppressed in TYLCV-infected tomatoes. Following suppression of the plant stress response, TYLCV can replicate and accumulate in a permissive environment. PMID:25962748

  20. Progressive aggregation of Tomato yellow leaf curl virus coat protein in systemically infected tomato plants, susceptible and resistant to the virus.

    PubMed

    Gorovits, Rena; Moshe, Adi; Kolot, Mikhail; Sobol, Iris; Czosnek, Henryk

    2013-01-01

    Tomato yellow leaf curl virus (TYLCV) coat protein (CP) accumulated in tomato leaves during infection. The CP was immuno-detected in the phloem associated cells. At the early stages of infection, punctate signals were detected in the cytoplasm, while in the later stages aggregates of increasing size were localized in cytoplasm and nuclei. Sedimentation of protein extracts through sucrose gradients confirmed that progress of infection was accompanied by the formation of CP aggregates of increasing size. Genomic ssDNA was found in the cytoplasm and in the nucleus, while the dsDNA replicative form was exclusively associated with the nucleus. CP-DNA complexes were detected by immuno-capture PCR in nuclear and cytoplasmic large aggregates. Nuclear aggregates contained infectious particles transmissible to test plants by whiteflies. In contrast to susceptible tomatoes, the formation of large CP aggregates in resistant plants was delayed. By experimentally changing the level of resistance/susceptibility of plants, we showed that maintenance of midsized CP aggregates was associated with resistance, while large aggregates where characteristic of susceptibility. We propose that sequestering of virus CP into midsized aggregates and retarding the formation of large insoluble aggregates containing infectious particles is part of the response of resistant plants to TYLCV. PMID:23099086

  1. Fine mapping of the tomato yellow leaf curl virus resistance gene Ty-2 on chromosome 11 of tomato.

    PubMed

    Yang, Xiaohui; Caro, Myluska; Hutton, Samuel F; Scott, John W; Guo, Yanmei; Wang, Xiaoxuan; Rashid, Md Harunur; Szinay, Dora; de Jong, Hans; Visser, Richard G F; Bai, Yuling; Du, Yongchen

    2014-01-01

    Resistances to begomoviruses, including bipartite tomato mottle virus and monopartite tomato yellow leaf curl virus (TYLCV), have been introgressed to cultivated tomato (Solanum lycopersicum) from wild tomato accessions. A major gene, Ty-2 from S. habrochaites f. glabratum accession "B6013," that confers resistance to TYLCV was previously mapped to a 19-cM region on the long arm of chromosome 11. In the present study, approximately 11,000 plants were screened and nearly 157 recombination events were identified between the flanking markers C2_At1g07960 (82.5 cM, physical distance 51.387 Mb) and T0302 (89 cM, 51.878 Mb). Molecular marker analysis of recombinants and TYLCV evaluation of progeny from these recombinants localized Ty-2 to an approximately 300,000-bp interval between markers UP8 (51.344 Mb) and M1 (51.645 Mb). No recombinants were identified between TG36 and C2_At3g52090, a region of at least 115 kb, indicating severe recombination suppression in this region. Due to the small interval, fluorescence in situ hybridization analysis failed to clarify whether recombination suppression is caused by chromosomal rearrangements. Candidate genes predicted based on tomato genome annotation were analyzed by RT-PCR and virus-induced gene silencing. Results indicate that the NBS gene family present in the Ty-2 region is likely not responsible for the Ty-2-conferred resistance and that two candidate genes might play a role in the Ty-2-conferred resistance. Several markers very tightly linked to the Ty-2 locus are presented and useful for marker-assisted selection in breeding programs to introgress Ty-2 for begomovirus resistance. PMID:25076841

  2. Microsatellite Diversity of Soybean Genotypes Differing in Bean Pod Mottle Virus Leaf Symptom

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean, Glycine max (L.) Merr, is the most important source of vegetable oil and protein meal in the world. Bean pod mottle virus (BPMV) is a threat to soybean yield and productivity in most soybean growing states of the USA. In the absence of complete resistance to BPMV, partial resistance of so...

  3. Effect of Raspberry bushy dwarf virus, Raspberry leaf mottle virus, and Raspberry latent virus on plant growth and fruit crumbliness in ‘Meeker’ red Raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raspberry crumbly fruit in red raspberry (Rubus idaeus L.), widespread in the Pacific Northwest of the United States and British Columbia, Canada, is most commonly caused by a virus infection. Raspberry bushy dwarf virus (RBDV) has long been attributed as the causal agent of the disease. Recently, t...

  4. Metal rolling - Asymmetrical rolling process

    NASA Astrophysics Data System (ADS)

    Alexa, V.; Raţiu, S.; Kiss, I.

    2016-02-01

    The development of theory and practice related to the asymmetric longitudinal rolling process is based on the general theory of metalworking by pressure and symmetric rolling theory, to which a large number of scientists brought their contribution. The rolling of metal materials was a serious problem throughout history, either economically or technically, because the plating technologies enabled the consumption of raw materials (scarce and expensive) to be reduced, while improving the mechanical properties. Knowing the force parameters related to asymmetric rolling leads to the optimization of energy and raw material consumption. This paper presents data on symmetric rolling process, in order to comparatively highlight the particularities of the asymmetric process.

  5. A developmentally regulated lipocalin-like gene is overexpressed in Tomato yellow leaf curl virus-resistant tomato plants upon virus inoculation, and its silencing abolishes resistance.

    PubMed

    Sade, Dagan; Eybishtz, Assaf; Gorovits, Rena; Sobol, Iris; Czosnek, Henryk

    2012-10-01

    To discover genes involved in tomato resistance to Tomato yellow leaf curl virus (TYLCV), we previously compared cDNA libraries from susceptible (S) and resistant (R) tomato lines. Among the genes preferentially expressed in R plants and upregulated by TYLCV infection was a gene encoding a lipocalin-like protein. This gene was termed Solanum lycopersicum virus resistant/susceptible lipocalin (SlVRSLip). The SlVRSLip structural gene sequence of R and S plants was identical. SlVRSLip was expressed in leaves during a 15-day window starting about 40 days after sowing (20 days after planting). SlVRSLip was upregulated by Bemisia tabaci (the TYLCV vector) feeding on R plant leaves, and even more strongly upregulated following whitefly-mediated TYLCV inoculation. Silencing of SlVRSLip in R plants led to the collapse of resistance upon TYLCV inoculation and to a necrotic response along the stem and petioles accompanied by ROS production. Contrary to previously identified tomato lipocalin gene DQ222981, SlVRSLip was not regulated by cold, nor was it regulated by heat or salt. The expression of SlVRSLip was inhibited in R plants in which the hexose transporter gene LeHT1 was silenced. In contrast, the expression of LeHT1 was not inhibited in SlVRSLip-silenced R plants. Hence, in the hierarchy of the gene network conferring TYLCV resistance, SlVRSLip is downstream of LeHT1. Silencing of another gene involved in resistance, a Permease-I like protein, did not affect the expression of SlVRSLip and LeHT1; expression of the Permease was not affected by silencing SlVRSLip or LeHT1, suggesting that it does not belong to the same network. The triple co-silencing of SlVRSLip, LeHT1 and Permease provoked an immediate cessation of growth of R plants upon infection and the accumulation of large amounts of virus. SlVRSLip is the first lipocalin-like gene shown to be involved in resistance to a plant virus. PMID:22843056

  6. A developmentally regulated lipocalin-like gene is overexpressed in Tomato yellow leaf curl virus-resistant tomato plants upon virus inoculation, and its silencing abolishes resistance.

    PubMed

    Sade, Dagan; Eybishtz, Assaf; Gorovits, Rena; Sobol, Iris; Czosnek, Henryk

    2012-10-01

    To discover genes involved in tomato resistance to Tomato yellow leaf curl virus (TYLCV), we previously compared cDNA libraries from susceptible (S) and resistant (R) tomato lines. Among the genes preferentially expressed in R plants and upregulated by TYLCV infection was a gene encoding a lipocalin-like protein. This gene was termed Solanum lycopersicum virus resistant/susceptible lipocalin (SlVRSLip). The SlVRSLip structural gene sequence of R and S plants was identical. SlVRSLip was expressed in leaves during a 15-day window starting about 40 days after sowing (20 days after planting). SlVRSLip was upregulated by Bemisia tabaci (the TYLCV vector) feeding on R plant leaves, and even more strongly upregulated following whitefly-mediated TYLCV inoculation. Silencing of SlVRSLip in R plants led to the collapse of resistance upon TYLCV inoculation and to a necrotic response along the stem and petioles accompanied by ROS production. Contrary to previously identified tomato lipocalin gene DQ222981, SlVRSLip was not regulated by cold, nor was it regulated by heat or salt. The expression of SlVRSLip was inhibited in R plants in which the hexose transporter gene LeHT1 was silenced. In contrast, the expression of LeHT1 was not inhibited in SlVRSLip-silenced R plants. Hence, in the hierarchy of the gene network conferring TYLCV resistance, SlVRSLip is downstream of LeHT1. Silencing of another gene involved in resistance, a Permease-I like protein, did not affect the expression of SlVRSLip and LeHT1; expression of the Permease was not affected by silencing SlVRSLip or LeHT1, suggesting that it does not belong to the same network. The triple co-silencing of SlVRSLip, LeHT1 and Permease provoked an immediate cessation of growth of R plants upon infection and the accumulation of large amounts of virus. SlVRSLip is the first lipocalin-like gene shown to be involved in resistance to a plant virus.

  7. Discovering Host Genes Involved in the Infection by the Tomato Yellow Leaf Curl Virus Complex and in the Establishment of Resistance to the Virus Using Tobacco Rattle Virus-based Post Transcriptional Gene Silencing

    PubMed Central

    Czosnek, Henryk; Eybishtz, Assaf; Sade, Dagan; Gorovits, Rena; Sobol, Iris; Bejarano, Eduardo; Rosas-Díaz, Tábata; Lozano-Durán, Rosa

    2013-01-01

    The development of high-throughput technologies allows for evaluating gene expression at the whole-genome level. Together with proteomic and metabolomic studies, these analyses have resulted in the identification of plant genes whose function or expression is altered as a consequence of pathogen attacks. Members of the Tomato yellow leaf curl virus (TYLCV) complex are among the most important pathogens impairing production of agricultural crops worldwide. To understand how these geminiviruses subjugate plant defenses, and to devise counter-measures, it is essential to identify the host genes affected by infection and to determine their role in susceptible and resistant plants. We have used a reverse genetics approach based on Tobacco rattle virus-induced gene silencing (TRV-VIGS) to uncover genes involved in viral infection of susceptible plants, and to identify genes underlying virus resistance. To identify host genes with a role in geminivirus infection, we have engineered a Nicotiana benthamiana line, coined 2IRGFP, which over-expresses GFP upon virus infection. With this system, we have achieved an accurate description of the dynamics of virus replication in space and time. Upon silencing selected N. benthamiana genes previously shown to be related to host response to geminivirus infection, we have identified eighteen genes involved in a wide array of cellular processes. Plant genes involved in geminivirus resistance were studied by comparing two tomato lines: one resistant (R), the other susceptible (S) to the virus. Sixty-nine genes preferentially expressed in R tomatoes were identified by screening cDNA libraries from infected and uninfected R and S genotypes. Out of the 25 genes studied so far, the silencing of five led to the total collapse of resistance, suggesting their involvement in the resistance gene network. This review of our results indicates that TRV-VIGS is an exquisite reverse genetics tool that may provide new insights into the molecular

  8. Discovering host genes involved in the infection by the Tomato Yellow Leaf Curl Virus complex and in the establishment of resistance to the virus using Tobacco Rattle Virus-based post transcriptional gene silencing.

    PubMed

    Czosnek, Henryk; Eybishtz, Assaf; Sade, Dagan; Gorovits, Rena; Sobol, Iris; Bejarano, Eduardo; Rosas-Díaz, Tábata; Lozano-Durán, Rosa

    2013-03-01

    The development of high-throughput technologies allows for evaluating gene expression at the whole-genome level. Together with proteomic and metabolomic studies, these analyses have resulted in the identification of plant genes whose function or expression is altered as a consequence of pathogen attacks. Members of the Tomato yellow leaf curl virus (TYLCV) complex are among the most important pathogens impairing production of agricultural crops worldwide. To understand how these geminiviruses subjugate plant defenses, and to devise counter-measures, it is essential to identify the host genes affected by infection and to determine their role in susceptible and resistant plants. We have used a reverse genetics approach based on Tobacco rattle virus-induced gene silencing (TRV-VIGS) to uncover genes involved in viral infection of susceptible plants, and to identify genes underlying virus resistance. To identify host genes with a role in geminivirus infection, we have engineered a Nicotiana benthamiana line, coined 2IRGFP, which over-expresses GFP upon virus infection. With this system, we have achieved an accurate description of the dynamics of virus replication in space and time. Upon silencing selected N. benthamiana genes previously shown to be related to host response to geminivirus infection, we have identified eighteen genes involved in a wide array of cellular processes. Plant genes involved in geminivirus resistance were studied by comparing two tomato lines: one resistant (R), the other susceptible (S) to the virus. Sixty-nine genes preferentially expressed in R tomatoes were identified by screening cDNA libraries from infected and uninfected R and S genotypes. Out of the 25 genes studied so far, the silencing of five led to the total collapse of resistance, suggesting their involvement in the resistance gene network. This review of our results indicates that TRV-VIGS is an exquisite reverse genetics tool that may provide new insights into the molecular

  9. Effect of Host Plant Resistance to Tomato yellow leaf curl virus (TYLCV) on Virus Acquisition and Transmission by Its Whitefly Vector.

    PubMed

    Lapidot, M; Friedmann, M; Pilowsky, M; Ben-Joseph, R; Cohen, S

    2001-12-01

    ABSTRACT The effect that Tomato yellow leaf curl virus (TYLCV)-infected resistant tomato plants may have on virus epidemiology was studied. Four tomato genotypes that exhibit different levels of viral resistance, ranging from fully susceptible to highly resistant, served as TYLCV-infected source plants. Viral acquisition and transmission rates by white-flies following feeding on the different source plants were evaluated. TYLCV transmission rate by whiteflies that had fed on infected source plants 21 days postinoculation (DPI), shortly after the appearance of TYLCV symptoms, was negatively correlated with the level of resistance displayed by the source plant. Therefore, the higher the resistance, the lower the transmission rate. In addition, TYLCV DNA accumulation was shown to be lower in the resistant source plants compared with the susceptible plants. Whitefly survival rate, following feeding on source plants 21 DPI, was similar for all the cultivars tested. Significant differences in whitefly survival were found, however, following feeding on the infected source plants at 35 DPI; here, whitefly survival rate increased with higher levels of resistance displayed by the source plant. At 35 DPI, the susceptible plants had developed severe TYLCV disease symptoms, and transmission rates from these plants were the lowest, presumably due to the poor condition of these plants. Transmission rates from source plants displaying a medium level of resistance level were highest, with rates declining following feeding on source plants displaying higher levels of TYLCV resistance. TYLCV DNA accumulation in whiteflies following feeding on infected source plants at both 21 and 35 DPI was directly correlated with viral DNA accumulation in source plants. Results show that, in essence, the higher the resistance expressed, the less suitable the plant was as a viral source. Consequently, following acquisition from a highly resistant plant, TYLCV transmission by whiteflies will be less

  10. Tomato yellow leaf curl virus infection mitigates the heat stress response of plants grown at high temperatures

    PubMed Central

    Ghandi, Anfoka; Adi, Moshe; Lilia, Fridman; Linoy, Amrani; Or, Rotem; Mikhail, Kolot; Mouhammad, Zeidan; Henryk, Czosnek; Rena, Gorovits

    2016-01-01

    Cultured tomatoes are often exposed to a combination of extreme heat and infection with Tomato yellow leaf curl virus (TYLCV). This stress combination leads to intense disease symptoms and yield losses. The response of TYLCV-susceptible and resistant tomatoes to heat stress together with viral infection was compared. The plant heat-stress response was undermined in TYLCV infected plants. The decline correlated with the down-regulation of heat shock transcription factors (HSFs) HSFA2 and HSFB1, and consequently, of HSF-regulated genes Hsp17, Apx1, Apx2 and Hsp90. We proposed that the weakened heat stress response was due to the decreased capacity of HSFA2 to translocate into the nuclei of infected cells. All the six TYLCV proteins were able to interact with tomato HSFA2 in vitro, moreover, coat protein developed complexes with HSFA2 in nuclei. Capturing of HSFA2 by viral proteins could suppress the transcriptional activation of heat stress response genes. Application of both heat and TYLCV stresses was accompanied by the development of intracellular large protein aggregates containing TYLCV proteins and DNA. The maintenance of cellular chaperones in the aggregated state, even after recovery from heat stress, prevents the circulation of free soluble chaperones, causing an additional decrease in stress response efficiency. PMID:26792235

  11. Mapping the subgenomic RNA promoter of the Citrus leaf blotch virus coat protein gene by Agrobacterium-mediated inoculation.

    PubMed

    Renovell, Agueda; Gago, Selma; Ruiz-Ruiz, Susana; Velázquez, Karelia; Navarro, Luis; Moreno, Pedro; Vives, Mari Carmen; Guerri, José

    2010-10-25

    Citrus leaf blotch virus has a single-stranded positive-sense genomic RNA (gRNA) of 8747 nt organized in three open reading frames (ORFs). The ORF1, encoding a polyprotein involved in replication, is translated directly from the gRNA, whereas ORFs encoding the movement (MP) and coat (CP) proteins are expressed via 3' coterminal subgenomic RNAs (sgRNAs). We characterized the minimal promoter region critical for the CP-sgRNA expression in infected cells by deletion analyses using Agrobacterium-mediated infection of Nicotiana benthamiana plants. The minimal CP-sgRNA promoter was mapped between nucleotides -67 and +50 nt around the transcription start site. Surprisingly, larger deletions in the region between the CP-sgRNA transcription start site and the CP translation initiation codon resulted in increased CP-sgRNA accumulation, suggesting that this sequence could modulate the CP-sgRNA transcription. Site-specific mutational analysis of the transcription start site revealed that the +1 guanylate and the +2 adenylate are important for CP-sgRNA synthesis.

  12. Synthesis and biological activity evaluation of novel amino acid derivatives as potential elicitors against Tomato yellow leaf curl virus.

    PubMed

    Deng, Yufang; He, Shun; Geng, Qianqian; Duan, Yongheng; Guo, Mingcheng; Li, Jianqiang; Cao, Yongsong

    2015-12-01

    Disease caused by Tomato yellow leaf curl virus (TYLCV) brings serious production losses of cultivated tomato worldwide. In our previous study, two novel amino acid derivatives exerted satisfactory antiviral activities against TYLCV. In this study, the variation of TYLCV, the transcriptional expression level of Ty-1 and the enzyme activities of POD and PPO in tomato were monitored after treatment with two amino acid derivatives to illustrate the antiviral mechanism. The results showed the symptom severity caused by TYLCV was reduced significantly by two compounds and was associated with the inhibition of viral DNA level at the early stage. Among three levels of concentration, the highest inhibition rate of CNBF-His was 40.66% at 1000 mg/L, for CNBF-Asn, the highest inhibition rate was 36.26% at 2000 mg/L 30 days post-inoculation. Two compounds could also enhance the activities of PPO and POD and the transcriptional expression level of Ty-1 which correlates with plant resistance in tomato. In the field test, two compounds increased the yields of tomato and the maximum increase of yield was 37.66%. This is the first report of novel amino acid derivatives inducing resistance in tomato plant against TYLCV. It is suggested that amino acid derivatives have the potential to be an effective approach against TYLCV in tomato plant.

  13. Use of Tomato yellow leaf curl virus (TYLCV) Rep Gene Sequences to Engineer TYLCV Resistance in Tomato.

    PubMed

    Yang, Y; Sherwood, T A; Patte, C P; Hiebert, E; Polston, J E

    2004-05-01

    ABSTRACT Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus (family Geminiviridae), causes severe losses in tomato production in the tropics and subtropics. In order to generate engineered resistance, eight different constructs of the TYLCV replication-associated protein (Rep) and C4 gene sequences were tested in transformed tomato inbred lines. Transgenic plants were screened for resistance to TYLCV using viruliferous whiteflies. No symptoms were observed and no TYLCV genomic DNA was detected by both hybridization and polymerase chain reaction in progenies of plants transformed with three constructs. This resistance was observed in plants that contained one of the following transgenes: 2/5Rep (81 nucleotides [nt] of the intergenic region [IR] plus 426 nt of the 5' end of the TYLCV Rep gene), Delta2/5Rep (85 nt of the IR plus 595 nt of the 5' end of the TYLCV Rep gene in the antisense orientation), and RepDelta2/5Rep (81 nt of the IR, the entire Rep gene, and 41 nt 3' to the end of the Rep gene fused to Delta2/5Rep). Our study differs from other transgenic Geminivirus resistance reports involving the Rep gene in that viruliferous whiteflies were used for challenge inoculation instead of agroinoculation or biolistic inoculation, and TYLCV resistance was evaluated under field conditions. PMID:18943768

  14. Generation and characterization of functional recombinant antibody fragments against tomato yellow leaf curl virus replication-associated protein.

    PubMed

    Safarnejad, M R; Fischer, R; Commandeur, U

    2008-01-01

    Tomato yellow leaf curl virus (TYLCV) is a complex of geminivirus species prevalent in the tropics and sub-tropics, which causes severe diseases in economically important crops such as tomato. Conventional strategies for disease management have shown little success and new approaches based on genetic engineering need to be considered. We generated two single-chain variable fragment antibodies (scFv-ScRep1 and scFv-ScRep2) that bound strongly to continuous epitopes within the TYLCV replication-associated protein (Rep). The TYLCV-Ir C1 gene (encoding Rep) was expressed as glutathione-S-transferase (GST) and maltose-binding protein (MBP) fusions. Purified MBP-Rep was used to immunize mice allowing the construction of naïve and pre-immunized scFv phage display libraries. Immunoassays showed that scFv-ScRep1 recognized an N-terminal epitope of Rep, whereas scFv-ScRep2 recognized a more central epitope. This is the first successful production of scFv antibodies against a geminivirus Rep, the initial step in the production of transgenic plants with resistance to TYLCV. PMID:19226769

  15. Synthesis and biological activity evaluation of novel amino acid derivatives as potential elicitors against Tomato yellow leaf curl virus.

    PubMed

    Deng, Yufang; He, Shun; Geng, Qianqian; Duan, Yongheng; Guo, Mingcheng; Li, Jianqiang; Cao, Yongsong

    2015-12-01

    Disease caused by Tomato yellow leaf curl virus (TYLCV) brings serious production losses of cultivated tomato worldwide. In our previous study, two novel amino acid derivatives exerted satisfactory antiviral activities against TYLCV. In this study, the variation of TYLCV, the transcriptional expression level of Ty-1 and the enzyme activities of POD and PPO in tomato were monitored after treatment with two amino acid derivatives to illustrate the antiviral mechanism. The results showed the symptom severity caused by TYLCV was reduced significantly by two compounds and was associated with the inhibition of viral DNA level at the early stage. Among three levels of concentration, the highest inhibition rate of CNBF-His was 40.66% at 1000 mg/L, for CNBF-Asn, the highest inhibition rate was 36.26% at 2000 mg/L 30 days post-inoculation. Two compounds could also enhance the activities of PPO and POD and the transcriptional expression level of Ty-1 which correlates with plant resistance in tomato. In the field test, two compounds increased the yields of tomato and the maximum increase of yield was 37.66%. This is the first report of novel amino acid derivatives inducing resistance in tomato plant against TYLCV. It is suggested that amino acid derivatives have the potential to be an effective approach against TYLCV in tomato plant. PMID:26162434

  16. Effect of plant age at inoculation on expression of genetic resistance to tomato yellow leaf curl virus.

    PubMed

    Levy, D; Lapidot, M

    2008-01-01

    To determine the effects of plant age on the expression of genetic resistance to tomato yellow leaf curl virus (TYLCV), six TYLCV-resistant and two susceptible tomato varieties were inoculated at 14, 28 or 45 days after sowing (DAS). Inoculation at 14 and 28 DAS was performed in the greenhouse, and the plants were transplanted to the field at 30 DAS. Inoculation at 45 DAS was performed in the field, by covering the target plants with polypropylene ("Agril") sheets and releasing viruliferous whiteflies under them. Resistance was assayed mainly by comparing yield components of inoculated plants to those of control, non-inoculated plants of the same variety. Symptom severity and plant height were also followed. Plant age at inoculation had no effect on disease-severity scores of the susceptible varieties, and little or no effect on those of the resistant varieties. In contrast, plant age at inoculation had a significant effect on the yield of all varieties tested. All varieties suffered a significant yield reduction due to inoculation with TYLCV; the lowest yield was produced by plants inoculated at 14 DAS. A smaller TYLCV-induced yield reduction (yield increase of 50 to 100%, depending on the variety's resistance level), was achieved following inoculation at 28 DAS. A further reduction in yield loss (yield increase of 30 to 40%) was achieved following inoculation at 45 DAS. Our results clearly demonstrate the occurrence of age-related (or mature-plant) resistance in tomato plants to TYLCV. PMID:18000639

  17. Tomato yellow leaf curl virus infection mitigates the heat stress response of plants grown at high temperatures.

    PubMed

    Ghandi, Anfoka; Adi, Moshe; Lilia, Fridman; Linoy, Amrani; Or, Rotem; Mikhail, Kolot; Mouhammad, Zeidan; Henryk, Czosnek; Rena, Gorovits

    2016-01-01

    Cultured tomatoes are often exposed to a combination of extreme heat and infection with Tomato yellow leaf curl virus (TYLCV). This stress combination leads to intense disease symptoms and yield losses. The response of TYLCV-susceptible and resistant tomatoes to heat stress together with viral infection was compared. The plant heat-stress response was undermined in TYLCV infected plants. The decline correlated with the down-regulation of heat shock transcription factors (HSFs) HSFA2 and HSFB1, and consequently, of HSF-regulated genes Hsp17, Apx1, Apx2 and Hsp90. We proposed that the weakened heat stress response was due to the decreased capacity of HSFA2 to translocate into the nuclei of infected cells. All the six TYLCV proteins were able to interact with tomato HSFA2 in vitro, moreover, coat protein developed complexes with HSFA2 in nuclei. Capturing of HSFA2 by viral proteins could suppress the transcriptional activation of heat stress response genes. Application of both heat and TYLCV stresses was accompanied by the development of intracellular large protein aggregates containing TYLCV proteins and DNA. The maintenance of cellular chaperones in the aggregated state, even after recovery from heat stress, prevents the circulation of free soluble chaperones, causing an additional decrease in stress response efficiency. PMID:26792235

  18. Tomato yellow leaf curl virus differentially influences plant defence responses to a vector and a non-vector herbivore.

    PubMed

    Su, Qi; Mescher, Mark C; Wang, Shaoli; Chen, Gong; Xie, Wen; Wu, Qingjun; Wang, Wenkai; Zhang, Youjun

    2016-03-01

    Plants frequently engage in simultaneous interactions with diverse classes of biotic antagonists. Differential induction of plant defence pathways by these antagonists, and interactions between pathways, can have important ecological implications; however, these effects are currently not well understood. We explored how Tomato yellow leaf curl virus (TYLCV) influenced the performance of its vector (Bemisia tabaci) and a non-vector herbivore (Tetranychus urticae) occurring separately or together on tomato plants (Solanum lycopersicum). TYLCV enhanced the performance of B. tabaci, although this effect was statistically significant only in the absence of T. urticae, which adversely affected B. tabaci performance regardless of infection status. In contrast, the performance of T. urticae was enhanced (only) by the combined presence of TYLCV and B. tabaci. Analyses of phytohormone levels and defence gene expression in wild-type tomatoes and various plant-defence mutants indicate that the enhancement of herbivore performance (for each species) entails the disruption of downstream defences in the jasmonic acid (JA) pathway. For T. urticae, this disruption appears to involve antagonistic effects of salicylic acid (SA), which is cumulatively induced to high levels by B. tabaci and TYLCV. In contrast, TYLCV was found to suppress JA-mediated responses to B. tabaci via mechanisms independent of SA. PMID:26436779

  19. Expression of stress-response proteins upon whitefly-mediated inoculation of Tomato yellow leaf curl virus in susceptible and resistant tomato plants.

    PubMed

    Gorovits, Rena; Akad, Fouad; Beery, Hila; Vidavsky, Favi; Mahadav, Assaf; Czosnek, Henryk

    2007-11-01

    To better understand the nature of resistance of tomato to the whitefly (Bemisia tabaci, B biotype)-transmitted Tomato yellow leaf curl virus (TYLCV), whiteflies and TYLCV were considered as particular cases of biotic stresses and virus resistance as a particular case of successful response to these stresses. Two inbred tomato lines issued from the same breeding program that used Solanum habrochaites as a TYLCV resistance source, one susceptible and the other resistant, were used to compare the expression of key proteins involved at different stages of the plant response with stresses: mitogen-activated protein kinases (MAPKs), cellular heat shock proteins (HSPs, proteases), and pathogenesis-related (PR) proteins. The two biotic stresses-non-viruliferous whitefly feeding and virus infection with viruliferous insects--led to a slow decline in abundance of MAPKs, HSPs, and chloroplast protease FtsH (but not chloroplast protease ClpC), and induced the activities of the PR proteins, beta-1,3-glucanase, and peroxidase. This decline was less pronounced in virus-resistant than in virus-susceptible lines. Contrary to whitefly infestation and virus infection, inoculation with the fungus Sclerotinia sclerotiorum induced a rapid accumulation of the stress proteins studied, followed by a decline; the virus-susceptible and -resistant tomato lines behaved similarly in response to the fungus. PMID:17977149

  20. Rapid spread of a recently introduced virus (tomato yellow leaf curl virus) and its vector Bemisia tabaci (Hemiptera: Aleyrodidae) in Liaoning Province, China.

    PubMed

    Zhang, Wan-Min; Fu, Hai-Bin; Wang, Wen-Hang; Piao, Chun-Shu; Tao, Yun-Li; Guo, Dong; Chu, Dong

    2014-02-01

    In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations. PMID:24665690

  1. Rolling Reloaded

    ERIC Educational Resources Information Center

    Jones, Simon A.; Nieminen, John M.

    2008-01-01

    Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 "Eur. J. Phys."…

  2. The Tomato Yellow Leaf Curl Virus resistance genes Ty-1 and Ty-3 are allelic and code for DFDGD-class RNA-dependent RNA polymerases.

    PubMed

    Verlaan, Maarten G; Hutton, Samuel F; Ibrahem, Ragy M; Kormelink, Richard; Visser, Richard G F; Scott, John W; Edwards, Jeremy D; Bai, Yuling

    2013-03-01

    Tomato Yellow Leaf Curl Virus Disease incited by Tomato yellow leaf curl virus (TYLCV) causes huge losses in tomato production worldwide and is caused by different related begomovirus species. Breeding for TYLCV resistance has been based on the introgression of multiple resistance genes originating from several wild tomato species. In this study we have fine-mapped the widely used Solanum chilense-derived Ty-1 and Ty-3 genes by screening nearly 12,000 plants for recombination events and generating recombinant inbred lines. Multiple molecular markers were developed and used in combination with disease tests to fine-map the genes to a small genomic region (approximately 70 kb). Using a Tobacco Rattle Virus-Virus Induced Gene Silencing approach, the resistance gene was identified. It is shown that Ty-1 and Ty-3 are allelic and that they code for a RNA-dependent RNA polymerase (RDR) belonging to the RDRγ type, which has an atypical DFDGD motif in the catalytic domain. In contrast to the RDRα type, characterized by a catalytic DLDGD motif, no clear function has yet been described for the RDRγ type, and thus the Ty-1/Ty-3 gene unveils a completely new class of resistance gene. Although speculative, the resistance mechanism of Ty-1/Ty-3 and its specificity towards TYLCV are discussed in light of the function of the related RDRα class in the amplification of the RNAi response in plants and transcriptional silencing of geminiviruses in plants. PMID:23555305

  3. Improved rolling circle amplification (RCA) of hepatitis B virus (HBV) relaxed-circular serum DNA (RC-DNA).

    PubMed

    Martel, Nora; Gomes, Selma A; Chemin, Isabelle; Trépo, Christian; Kay, Alan

    2013-11-01

    For functional analysis of HBV isolates, epidemiological studies and correct identification of recombinant genomes, the amplification of complete genomes is necessary. A method for completely in vitro amplification of full-length HBV genomes starting from serum RC-DNA is described. This uses in vitro completion/ligation of plus-strand HBV RC-DNA and amplification using Rolling-Circle Amplification, eventually followed by a genomic PCR. The method can amplify complete HBV genomes from sera with viral loads ranging from >1.0E+8 IU/ml down to 1.0E+3 IU/ml. The method can be applied to archived sera that have undergone long-term storage or to archived DNA serum extracts. The genomes can easily be cloned. HBV genotypes A-G can all be amplified with no apparent problems. A recombinant subgenotype A3/genotype E genome was identified and fully sequenced.

  4. Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum).

    PubMed

    Nazeer, W; Ahmad, S; Mahmood, K; Tipu, A L; Mahmood, A; Zhou, B

    2014-01-01

    Cotton leaf curl virus disease is a major hurdle for successful cotton production in Pakistan. There has been considerable economic loss due to this disease during the last decade. It would be desirable to have cotton varieties resistant to this disease. We explored the possibility of transferring virus resistant genes from the wild species Gossypium stocksii into MNH-786, a cultivar of G. hirsutum. Hybridization was done under field condition at the Cotton Research Station, Multan, during 2010-11. Boll shedding was controlled by application of exogenous hormones. F1 seeds were treated with 0.03% colchicine solution for 6 h and germinated. Cytological observations at peak squaring/flowering stage showed that these plants were hexaploid, having 2n = 6x = 78 chromosomes. The F1 plants showed intermediate expression for leaf size, leaf area, petiole length, bracteole number and size, bracteole area, bracteole dentation, flower size, pedicel size, and petal number and size. Moreover it possessed high fiber strength of 54.4 g/tex, which is 54% greater than that of the check variety, i.e. MNH-786 (G. hirsutum). The F1 population did not show any symptom of CLCuVD in the field, tested by grafting with CLCuVD susceptible rootstock (var. S12). We conclude that it is possible to transfer CLCuVD resistance and high fiber strength from G. stocksii to G. hirsutum. PMID:24634169

  5. Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum).

    PubMed

    Nazeer, W; Ahmad, S; Mahmood, K; Tipu, A L; Mahmood, A; Zhou, B

    2014-02-21

    Cotton leaf curl virus disease is a major hurdle for successful cotton production in Pakistan. There has been considerable economic loss due to this disease during the last decade. It would be desirable to have cotton varieties resistant to this disease. We explored the possibility of transferring virus resistant genes from the wild species Gossypium stocksii into MNH-786, a cultivar of G. hirsutum. Hybridization was done under field condition at the Cotton Research Station, Multan, during 2010-11. Boll shedding was controlled by application of exogenous hormones. F1 seeds were treated with 0.03% colchicine solution for 6 h and germinated. Cytological observations at peak squaring/flowering stage showed that these plants were hexaploid, having 2n = 6x = 78 chromosomes. The F1 plants showed intermediate expression for leaf size, leaf area, petiole length, bracteole number and size, bracteole area, bracteole dentation, flower size, pedicel size, and petal number and size. Moreover it possessed high fiber strength of 54.4 g/tex, which is 54% greater than that of the check variety, i.e. MNH-786 (G. hirsutum). The F1 population did not show any symptom of CLCuVD in the field, tested by grafting with CLCuVD susceptible rootstock (var. S12). We conclude that it is possible to transfer CLCuVD resistance and high fiber strength from G. stocksii to G. hirsutum.

  6. Viruses Roll the Dice: The Stochastic Behavior of Viral Genome Molecules Accelerates Viral Adaptation at the Cell and Tissue Levels

    PubMed Central

    Miyashita, Shuhei; Ishibashi, Kazuhiro; Kishino, Hirohisa; Ishikawa, Masayuki

    2015-01-01

    Recent studies on evolutionarily distant viral groups have shown that the number of viral genomes that establish cell infection after cell-to-cell transmission is unexpectedly small (1–20 genomes). This aspect of viral infection appears to be important for the adaptation and survival of viruses. To clarify how the number of viral genomes that establish cell infection is determined, we developed a simulation model of cell infection for tomato mosaic virus (ToMV), a positive-strand RNA virus. The model showed that stochastic processes that govern the replication or degradation of individual genomes result in the infection by a small number of genomes, while a large number of infectious genomes are introduced in the cell. It also predicted two interesting characteristics regarding cell infection patterns: stochastic variation among cells in the number of viral genomes that establish infection and stochastic inequality in the accumulation of their progenies in each cell. Both characteristics were validated experimentally by inoculating tobacco cells with a library of nucleotide sequence–tagged ToMV and analyzing the viral genomes that accumulated in each cell using a high-throughput sequencer. An additional simulation model revealed that these two characteristics enhance selection during tissue infection. The cell infection model also predicted a mechanism that enhances selection at the cellular level: a small difference in the replication abilities of coinfected variants results in a large difference in individual accumulation via the multiple-round formation of the replication complex (i.e., the replication machinery). Importantly, this predicted effect was observed in vivo. The cell infection model was robust to changes in the parameter values, suggesting that other viruses could adopt similar adaptation mechanisms. Taken together, these data reveal a comprehensive picture of viral infection processes including replication, cell-to-cell transmission, and

  7. Viruses roll the dice: the stochastic behavior of viral genome molecules accelerates viral adaptation at the cell and tissue levels.

    PubMed

    Miyashita, Shuhei; Ishibashi, Kazuhiro; Kishino, Hirohisa; Ishikawa, Masayuki

    2015-03-01

    Recent studies on evolutionarily distant viral groups have shown that the number of viral genomes that establish cell infection after cell-to-cell transmission is unexpectedly small (1-20 genomes). This aspect of viral infection appears to be important for the adaptation and survival of viruses. To clarify how the number of viral genomes that establish cell infection is determined, we developed a simulation model of cell infection for tomato mosaic virus (ToMV), a positive-strand RNA virus. The model showed that stochastic processes that govern the replication or degradation of individual genomes result in the infection by a small number of genomes, while a large number of infectious genomes are introduced in the cell. It also predicted two interesting characteristics regarding cell infection patterns: stochastic variation among cells in the number of viral genomes that establish infection and stochastic inequality in the accumulation of their progenies in each cell. Both characteristics were validated experimentally by inoculating tobacco cells with a library of nucleotide sequence-tagged ToMV and analyzing the viral genomes that accumulated in each cell using a high-throughput sequencer. An additional simulation model revealed that these two characteristics enhance selection during tissue infection. The cell infection model also predicted a mechanism that enhances selection at the cellular level: a small difference in the replication abilities of coinfected variants results in a large difference in individual accumulation via the multiple-round formation of the replication complex (i.e., the replication machinery). Importantly, this predicted effect was observed in vivo. The cell infection model was robust to changes in the parameter values, suggesting that other viruses could adopt similar adaptation mechanisms. Taken together, these data reveal a comprehensive picture of viral infection processes including replication, cell-to-cell transmission, and evolution

  8. Tomato yellow leaf curl virus infection of a resistant tomato line with a silenced sucrose transporter gene LeHT1 results in inhibition of growth, enhanced virus spread, and necrosis.

    PubMed

    Eybishtz, Assaf; Peretz, Yuval; Sade, Dagan; Gorovits, Rena; Czosnek, Henryk

    2010-02-01

    To identify genes involved in resistance of tomato to Tomato yellow leaf curl virus (TYLCV), cDNA libraries from lines resistant (R) and susceptible (S) to the virus were compared. The hexose transporter LeHT1 was found to be expressed preferentially in R tomato plants. The role of LeHT1 in the establishment of TYLCV resistance was studied in R plants where LeHT1 has been silenced using Tobacco rattle virus-induced gene silencing (TRV VIGS). Following TYLCV inoculation, LeHT1-silenced R plants showed inhibition of growth and enhanced virus accumulation and spread. In addition, a necrotic response was observed along the stem and petioles of infected LeHT1-silenced R plants, but not on infected not-silenced R plants. This response was specific of R plants since it was absent in infected LeHT1-silenced S plants. Necrosis had several characteristics of programmed cell death (PCD): DNA from necrotic tissues presented a PCD-characteristic ladder pattern, the amount of a JNK analogue increased, and production of reactive oxygen was identified by DAB staining. A similar necrotic reaction along stem and petioles was observed in LeHT1-silenced R plants infected with the DNA virus Bean dwarf mosaic virus and the RNA viruses Cucumber mosaic virus and Tobacco mosaic virus. These results constitute the first evidence for a necrotic response backing natural resistance to TYLCV in tomato, confirming that plant defense is organized in multiple layers. They demonstrate that the hexose transporter LeHT1 is essential for the expression of natural resistance against TYLCV and its expression correlates with inhibition of virus replication and movement. PMID:19946703

  9. Resistance to Tomato yellow leaf curl virus accumulation in the tomato wild relative Solanum habrochaites associated with the C4 viral protein.

    PubMed

    Tomás, Diego M; Cañizares, M Carmen; Abad, Jesús; Fernández-Muñoz, Rafael; Moriones, Enrique

    2011-07-01

    Tomato yellow leaf curl disease (TYLCD) is a severe threat to tomato crops worldwide and is caused by Tomato yellow leaf curl virus (TYLCV) and several other begomoviruses (genus Begomovirus, family Geminiviridae). Host plant resistance is the best TYLCD control method but limited sources of resistance are available. In this study, two Solanum habrochaites TYLCD-resistance sources, EELM-388 and EELM-889, were found after a wide germplasm screening and were further characterized. A consistent resistance to the widely distributed strain TYLCV-IL was observed when plants were inoculated by Bemisia tabaci or by agroinoculation using an infectious clone, with no symptoms or virus accumulation observed in inoculated plants. Moreover, the resistance was effective under field conditions with high TYLCD pressure. Two independent loci, one dominant and one recessive, were associated with EELM-889 resistance. The study shows these loci to be distinct from that of the resistance gene (Ty-1 gene) commonly deployed in commercial tomato cultivars. Therefore, both kinds of resistance could be combined to provide improved resistance to TYLCD. Four additional TYLCD-associated viruses were challenged, showing that the resistance always prevented symptom expression, although systemic infection could occur in some cases. By using chimeric and mutant expression constructs, the C4 protein was shown to be associated with the ability to result in effective systemic infection. PMID:21405986

  10. Detection of Multiple Potato Viruses in the Field Suggests Synergistic Interactions among Potato Viruses in Pakistan.

    PubMed

    Hameed, Amir; Iqbal, Zafar; Asad, Shaheen; Mansoor, Shahid

    2014-12-01

    Viral diseases have been a major limiting factor threating sustainable potato (Solanum tuberosum L.) production in Pakistan. Surveys were conducted to serologically quantify the incidence of RNA viruses infecting potato; Potato virus X (PVX), Potato virus Y (PVY), Potato virus S (PVS), Potato virus A (PVA), Potato virus M (PVM) and Potato leaf roll virus (PLRV) in two major potato cultivars (Desiree and Cardinal). The results suggest the prevalence of multiple viruses in all surveyed areas with PVY, PVS and PVX dominantly widespread with infection levels of up to 50% in some regions. Co-infections were detected with the highest incidence (15.5%) for PVX and PVS. Additionally the data showed a positive correlation between co-infecting viruses with significant increase in absorbance value (virus titre) for at least one of the virus in an infected plant and suggested a synergistic interaction. To test this hypothesis, glasshouse grown potato plants were challenged with multiple viruses and analyzed for systemic infections and symptomology studies. The results obtained conclude that multiple viral infections dramatically increase disease epidemics as compared to single infection and an effective resistance strategy in targeting multiple RNA viruses is required to save potato crop. PMID:25506305

  11. Heritable, de novo resistance to leaf rust and other novel traits in selfed descendants of wheat responding to inoculation with wheat streak mosaic virus.

    PubMed

    Seifers, Dallas L; Haber, Steve; Martin, Terry J; McCallum, Brent D

    2014-01-01

    Stable resistance to infection with Wheat streak mosaic virus (WSMV) can be evolved de novo in selfing bread wheat lines subjected to cycles of WSMV inoculation and selection of best-performing plants or tillers. To learn whether this phenomenon might be applied to evolve resistance de novo to pathogens unrelated to WSMV, we examined the responses to leaf rust of succeeding generations of the rust- and WSMV-susceptible cultivar 'Lakin' following WSMV inoculation and derived rust-resistant sublines. After three cycles of the iterative protocol five plants, in contrast to all others, expressed resistance to leaf and stripe rust. A subset of descendant sublines of one of these, 'R1', heritably and uniformly expressed the new trait of resistance to leaf rust. Such sublines, into which no genes from a known source of resistance had been introgressed, conferred resistance to progeny of crosses with susceptible parents. The F1 populations produced from crosses between, respectively, susceptible and resistant 'Lakin' sublines 4-3-3 and 4-12-3 were not all uniform in their response to seedling inoculation with race TDBG. In seedling tests against TDBG and MKPS races the F2s from F1 populations that were uniformly resistant had 3∶1 ratios of resistant to susceptible individuals but the F2s from susceptible F1 progenitors were uniformly susceptible. True-breeding lines derived from resistant individuals in F2 populations were resistant to natural stripe and leaf rust inoculum in the field, while the 'Lakin' progenitor was susceptible. The next generation of six of the 'Lakin'-derived lines exhibited moderate to strong de novo resistance to stem rust races TPMK, QFCS and RKQQ in seedling tests while the 'Lakin' progenitor was susceptible. These apparently epigenetic effects in response to virus infection may help researchers fashion a new tool that expands the range of genetic resources already available in adapted germplasm.

  12. Association of a distinct strain of hollyhock yellow vein mosaic virus and Ludwigia leaf distortion betasatellite with yellow vein mosaic disease of hollyhock (Alcea rosea) in India.

    PubMed

    Srivastava, A; Kumar, S; Raj, S K; Pande, S S

    2014-10-01

    A distinct strain of hollyhock yellow vein mosaic virus (HoYVMV) and Ludwigia leaf distortion betasatellite (LuLDB) were associated with yellow vein mosaic of hollyhock. The viral DNA genome (JQ911766) and betasatellite (JQ408216) shared highest nucleotide sequence identity (89.2 %) with HoYVMV (the only available sequence in GenBank) and 92 % identity with LuLDB. Agroinfiltration of HoYVMV and LuLDB induced yellow vein mosaic symptoms on hollyhock, thereby demonstrating causality of the disease.

  13. First complete genomic characterization and phylogeny of a new recombinant of tomato yellow leaf curl virus (genus Begomovirus, family Geminiviridae) from Kuwait.

    PubMed

    Al-Ali, Ebtisam H M; Al-Hashash, Hanadi K; Ben-Hejji, Ahmed H; Al-Shayjji, Nabella; Al-Aqeel, Hamed A

    2015-07-01

    While whitefly-transmitted begomoviruses are economically important constraints to tomato production in Kuwait, little is known about genomic features of these viruses from Kuwait. A begomovirus isolated from severely diseased tomatoes, collected over a two-year period in the main tomato-growing areas of Kuwait, was characterized at the molecular level. The complete genomic sequence of the begomovirus was determined, and phlylogeographic studies were conducted to better understand genetic diversity of the virus in the region. Based on genome properties and phylogenetic analysis, the begomovirus was found to be a strain of tomato yellow leaf curl virus (TYLCV). The virus genome was monopartite, as neither DNA B nor satellite DNA molecules were detected. Two isolates characterized in this study shared 97% and 95% nucleotide sequence identity with a previously characterized Kuwaiti isolate, TYLCV-KISR. Among TYLCV isolates with known genome sequences, the Kuwaiti isolates shared highest sequence identity (95%) with TYLCV-Almeria (Spain). Genetic diversity and phylogenetic analysis showed that the three Kuwaiti isolates formed a distinct clade that was separate from those of known TYLCV sequences. One Kuwaiti isolate (KW 1-3) could be a novel variant of TYLCV. Two recombination events were detected in the genome sequence of KW 1-3, which appeared to be a recombinant derived from TYLCV parents from Oman and Kuwait. PMID:25951968

  14. Transgenic tomato plants expressing artificial microRNAs for silencing the pre-coat and coat proteins of a begomovirus, Tomato leaf curl New Delhi virus, show tolerance to virus infection.

    PubMed

    Vu, Tien Van; Choudhury, Nirupam Roy; Mukherjee, Sunil Kumar

    2013-03-01

    Designing artificial microRNAs (amiRs) targeting the genes responsible for viral replication, transmission and symptom development after viral infection offers a promising strategy to contain the multiplication and spread of geminiviruses in host plants. Here, we report the design of two amiRs targeting the middle region of the AV1 (coat protein) transcript (amiR-AV1-3) and the overlapping region of the AV1 and AV2 (pre-coat protein) transcripts (amiR-AV1-1) of a model geminivirus, Tomato leaf curl virus (ToLCV). Our analyses demonstrate that transgenic tomato plants expressing amiR-AV1-1, propagated until the T2 generation and were highly tolerant to Tomato leaf curl New Delhi virus (ToLCNDV), whereas those harboring amiR-AV1-3 exhibited only moderate tolerance. Biochemical analyses revealed that in these cases, the amiRs acted through the slicing mechanism, cleaving their respective targets. Although ToLCVs are generally difficult targets for manipulations related to virus resistance, our data reveal that an amiR strategy could be employed to protect plants in an effective manner.

  15. The complete genomic sequence of pepper yellow leaf curl virus (PYLCV) and its implications for our understanding of evolution dynamics in the genus polerovirus.

    PubMed

    Dombrovsky, Aviv; Glanz, Eyal; Lachman, Oded; Sela, Noa; Doron-Faigenboim, Adi; Antignus, Yehezkel

    2013-01-01

    We determined the complete sequence and organization of the genome of a putative member of the genus Polerovirus tentatively named Pepper yellow leaf curl virus (PYLCV). PYLCV has a wider host range than Tobacco vein-distorting virus (TVDV) and has a close serological relationship with Cucurbit aphid-borne yellows virus (CABYV) (both poleroviruses). The extracted viral RNA was subjected to SOLiD next-generation sequence analysis and used as a template for reverse transcription synthesis, which was followed by PCR amplification. The ssRNA genome of PYLCV includes 6,028 nucleotides encoding six open reading frames (ORFs), which is typical of the genus Polerovirus. Comparisons of the deduced amino acid sequences of the PYLCV ORFs 2-4 and ORF5, indicate that there are high levels of similarity between these sequences to ORFs 2-4 of TVDV (84-93%) and to ORF5 of CABYV (87%). Both PYLCV and Pepper vein yellowing virus (PeVYV) contain sequences that point to a common ancestral polerovirus. The recombination breakpoint which is located at CABYV ORF3, which encodes the viral coat protein (CP), may explain the CABYV-like sequences found in the genomes of the pepper infecting viruses PYLCV and PeVYV. Two additional regions unique to PYLCV (PY1 and PY2) were identified between nucleotides 4,962 and 5,061 (ORF 5) and between positions 5,866 and 6,028 in the 3' NCR. Sequence analysis of the pepper-infecting PeVYV revealed three unique regions (Pe1-Pe3) with no similarity to other members of the genus Polerovirus. Genomic analyses of PYLCV and PeVYV suggest that the speciation of these viruses occurred through putative recombination event(s) between poleroviruses co-infecting a common host(s), resulting in the emergence of PYLCV, a novel pathogen with a wider host range.

  16. The Complete Genomic Sequence of Pepper Yellow Leaf Curl Virus (PYLCV) and Its Implications for Our Understanding of Evolution Dynamics in the Genus Polerovirus

    PubMed Central

    Dombrovsky, Aviv; Glanz, Eyal; Lachman, Oded; Sela, Noa; Doron-Faigenboim, Adi; Antignus, Yehezkel

    2013-01-01

    We determined the complete sequence and organization of the genome of a putative member of the genus Polerovirus tentatively named Pepper yellow leaf curl virus (PYLCV). PYLCV has a wider host range than Tobacco vein-distorting virus (TVDV) and has a close serological relationship with Cucurbit aphid-borne yellows virus (CABYV) (both poleroviruses). The extracted viral RNA was subjected to SOLiD next-generation sequence analysis and used as a template for reverse transcription synthesis, which was followed by PCR amplification. The ssRNA genome of PYLCV includes 6,028 nucleotides encoding six open reading frames (ORFs), which is typical of the genus Polerovirus. Comparisons of the deduced amino acid sequences of the PYLCV ORFs 2-4 and ORF5, indicate that there are high levels of similarity between these sequences to ORFs 2-4 of TVDV (84-93%) and to ORF5 of CABYV (87%). Both PYLCV and Pepper vein yellowing virus (PeVYV) contain sequences that point to a common ancestral polerovirus. The recombination breakpoint which is located at CABYV ORF3, which encodes the viral coat protein (CP), may explain the CABYV-like sequences found in the genomes of the pepper infecting viruses PYLCV and PeVYV. Two additional regions unique to PYLCV (PY1 and PY2) were identified between nucleotides 4,962 and 5,061 (ORF 5) and between positions 5,866 and 6,028 in the 3' NCR. Sequence analysis of the pepper-infecting PeVYV revealed three unique regions (Pe1-Pe3) with no similarity to other members of the genus Polerovirus. Genomic analyses of PYLCV and PeVYV suggest that the speciation of these viruses occurred through putative recombination event(s) between poleroviruses co-infecting a common host(s), resulting in the emergence of PYLCV, a novel pathogen with a wider host range. PMID:23936244

  17. The complete genomic sequence of pepper yellow leaf curl virus (PYLCV) and its implications for our understanding of evolution dynamics in the genus polerovirus.

    PubMed

    Dombrovsky, Aviv; Glanz, Eyal; Lachman, Oded; Sela, Noa; Doron-Faigenboim, Adi; Antignus, Yehezkel

    2013-01-01

    We determined the complete sequence and organization of the genome of a putative member of the genus Polerovirus tentatively named Pepper yellow leaf curl virus (PYLCV). PYLCV has a wider host range than Tobacco vein-distorting virus (TVDV) and has a close serological relationship with Cucurbit aphid-borne yellows virus (CABYV) (both poleroviruses). The extracted viral RNA was subjected to SOLiD next-generation sequence analysis and used as a template for reverse transcription synthesis, which was followed by PCR amplification. The ssRNA genome of PYLCV includes 6,028 nucleotides encoding six open reading frames (ORFs), which is typical of the genus Polerovirus. Comparisons of the deduced amino acid sequences of the PYLCV ORFs 2-4 and ORF5, indicate that there are high levels of similarity between these sequences to ORFs 2-4 of TVDV (84-93%) and to ORF5 of CABYV (87%). Both PYLCV and Pepper vein yellowing virus (PeVYV) contain sequences that point to a common ancestral polerovirus. The recombination breakpoint which is located at CABYV ORF3, which encodes the viral coat protein (CP), may explain the CABYV-like sequences found in the genomes of the pepper infecting viruses PYLCV and PeVYV. Two additional regions unique to PYLCV (PY1 and PY2) were identified between nucleotides 4,962 and 5,061 (ORF 5) and between positions 5,866 and 6,028 in the 3' NCR. Sequence analysis of the pepper-infecting PeVYV revealed three unique regions (Pe1-Pe3) with no similarity to other members of the genus Polerovirus. Genomic analyses of PYLCV and PeVYV suggest that the speciation of these viruses occurred through putative recombination event(s) between poleroviruses co-infecting a common host(s), resulting in the emergence of PYLCV, a novel pathogen with a wider host range. PMID:23936244

  18. Reduction of leaf area and symptom severity as proxies of disease-induced plant mortality: the example of the Cauliflower mosaic virus infecting two Brassicaceae hosts.

    PubMed

    Doumayrou, Juliette; Leblaye, Sophie; Froissart, Rémy; Michalakis, Yannis

    2013-09-01

    Disease induced effects on host survival are important to understand the evolution of parasitic virulence and host resistance/tolerance. Unfortunately, experiments evaluating such effects are in most cases logistically demanding justifying the measurement of survival proxies. For plant hosts commonly used proxies are leaf area and the nature and severity of visual qualitative disease symptoms. In this study we tested whether these traits are indeed correlated to the host mortality rate induced by viral infection. We infected Brassica rapa and Arabidopsis thaliana plants with different natural isolates of Cauliflower mosaic virus (CaMV) and estimated over time the development of symptoms and the relative reduction of leaf area compared to healthy plants and followed plant mortality. We observed that the mortality of infected plants was correlated with the relative reduction of leaf area of both B. rapa and A. thaliana. Measures of mortality were also correlated with the severity of visual qualitative symptoms but the magnitude of the correlations and the time frame at which they were significant depended on the host plant: stronger and earlier correlations were observed on A. thaliana.

  19. Reduction of leaf area and symptom severity as proxies of disease-induced plant mortality: the example of the Cauliflower mosaic virus infecting two Brassicaceae hosts.

    PubMed

    Doumayrou, Juliette; Leblaye, Sophie; Froissart, Rémy; Michalakis, Yannis

    2013-09-01

    Disease induced effects on host survival are important to understand the evolution of parasitic virulence and host resistance/tolerance. Unfortunately, experiments evaluating such effects are in most cases logistically demanding justifying the measurement of survival proxies. For plant hosts commonly used proxies are leaf area and the nature and severity of visual qualitative disease symptoms. In this study we tested whether these traits are indeed correlated to the host mortality rate induced by viral infection. We infected Brassica rapa and Arabidopsis thaliana plants with different natural isolates of Cauliflower mosaic virus (CaMV) and estimated over time the development of symptoms and the relative reduction of leaf area compared to healthy plants and followed plant mortality. We observed that the mortality of infected plants was correlated with the relative reduction of leaf area of both B. rapa and A. thaliana. Measures of mortality were also correlated with the severity of visual qualitative symptoms but the magnitude of the correlations and the time frame at which they were significant depended on the host plant: stronger and earlier correlations were observed on A. thaliana. PMID:23742852

  20. Water Balance, Hormone Homeostasis, and Sugar Signaling Are All Involved in Tomato Resistance to Tomato Yellow Leaf Curl Virus1[C][W][OPEN

    PubMed Central

    Sade, Dagan; Sade, Nir; Shriki, Oz; Lerner, Stephen; Gebremedhin, Alem; Karavani, Asaf; Brotman, Yariv; Osorio, Sonia; Fernie, Alisdair R.; Willmitzer, Lothar; Czosnek, Henryk; Moshelion, Menachem

    2014-01-01

    Vacuolar water movement is largely controlled by membrane channels called tonoplast-intrinsic aquaporins (TIP-AQPs). Some TIP-AQP genes, such as TIP2;2 and TIP1;1, are up-regulated upon exposure to biotic stress. Moreover, TIP1;1 transcript levels are higher in leaves of a tomato (Solanum lycopersicum) line resistant to Tomato yellow leaf curl virus (TYLCV) than in those of a susceptible line with a similar genetic background. Virus-induced silencing of TIP1;1 in the tomato resistant line and the use of an Arabidopsis (Arabidopsis thaliana) tip1;1 null mutant showed that resistance to TYLCV is severely compromised in the absence of TIP1:1. Constitutive expression of tomato TIP2;2 in transgenic TYLCV-susceptible tomato and Arabidopsis plants was correlated with increased TYLCV resistance, increased transpiration, decreased abscisic acid levels, and increased salicylic acid levels at the early stages of infection. We propose that TIP-AQPs affect the induction of leaf abscisic acid, which leads to increased levels of transpiration and gas exchange, as well as better salicylic acid signaling. PMID:24989233

  1. Intron-hairpin RNA derived from replication associated protein C1 gene confers immunity to tomato yellow leaf curl virus infection in transgenic tomato plants.

    PubMed

    Fuentes, Alejandro; Ramos, Pedro L; Fiallo, Elvira; Callard, Danay; Sánchez, Yadira; Peral, Rudy; Rodríguez, Raidel; Pujol, Merardo

    2006-06-01

    The whitefly-transmitted Tomato Yellow Leaf Curl Virus (TYLCV) is the major pathogen of tomato crop in Cuba and one of the most outstanding viral diseases of plants worldwide. In this work, we have developed transgenic tomato plants, transformed with an intron-hairpin genetic construction to induce post- transcriptional gene silencing against the early TYLCV replication associated protein gene (C1). The intron-hairpin RNA produced involves 726 nts of the 3' end of the TYLCV C1 gene as the arms of the hairpin, and the castor bean catalase intron. Transgenic tomato plants belonging to line 126, which harbor a single transgene copy, showed immunity to TYLCV, even in extreme conditions of infection (4-leaf-stage plants and 300 to many hundreds viruliferous whiteflies per plant during 60 days). Dot blot hybridization of these plants showed no TYLCV DNA presence 60 days after inoculation. Small interfering RNA molecules were detected in both inoculated and non-inoculated plants from line 126. These transgenic tomato plants of the otherwise very TYLCV-susceptible Campbell-28 tomato cultivar, are the first report of resistance to a plant DNA virus obtained by the use of the intron-hairpin RNA approach. PMID:16779645

  2. Analysis of the Mild strain of tomato yellow leaf curl virus, which overcomes Ty-2 gene-mediated resistance in tomato line H24.

    PubMed

    Ohnishi, Jun; Yamaguchi, Hirotaka; Saito, Atsushi

    2016-08-01

    In tomato line H24, an isolate of the Mild (Mld) strain of tomato yellow leaf curl virus (TYLCV-Mld [JR:Kis]) overcomes Ty-2 gene-mediated resistance and causes typical symptoms of tomato yellow leaf curl disease (TYLCD). No systemic infection with visible symptoms or accumulation of viral DNA in the upper leaves was observed in H24 challenged with another isolate, TYLCV-IL (TYLCV-IL [JR:Osaka]), confirming that H24 is resistant to the IL strain. To elucidate the genomic regions that cause the breakdown of the Ty-2 gene-mediated resistance, we constructed a series of chimeras by swapping genes between the two strains. A chimeric virus that had the overlapping C4/Rep region of the Mld strain in the context of the IL strain genome, caused severe TYLCD in H24 plants, suggesting that the overlapping C4/Rep region of the Mld strain is associated with the ability of this strain to overcome Ty-2 gene-mediated resistance. PMID:27231006

  3. Comparative transcriptome profiling of a resistant vs. susceptible tomato (Solanum lycopersicum) cultivar in response to infection by tomato yellow leaf curl virus.

    PubMed

    Chen, Tianzi; Lv, Yuanda; Zhao, Tongming; Li, Nan; Yang, Yuwen; Yu, Wengui; He, Xin; Liu, Tingli; Zhang, Baolong

    2013-01-01

    Tomato yellow leaf curl virus (TYLCV) threatens tomato production worldwide by causing leaf yellowing, leaf curling, plant stunting and flower abscission. The current understanding of the host plant defense response to this virus is very limited. Using whole transcriptome sequencing, we analyzed the differential gene expression in response to TYLCV infection in the TYLCV-resistant tomato breeding line CLN2777A (R) and TYLCV-susceptible tomato breeding line TMXA48-4-0 (S). The mixed inoculated samples from 3, 5 and 7 day post inoculation (dpi) were compared to non-inoculated samples at 0 dpi. Of the total of 34831 mapped transcripts, 209 and 809 genes were differentially expressed in the R and S tomato line, respectively. The proportion of up-regulated differentially expressed genes (DEGs) in the R tomato line (58.37%) was higher than that in the S line (9.17%). Gene ontology (GO) analyses revealed that similar GO terms existed in both DEGs of R and S lines; however, some sets of defense related genes and their expression levels were not similar between the two tomato lines. Genes encoding for WRKY transcriptional factors, R genes, protein kinases and receptor (-like) kinases which were identified as down-regulated DEGs in the S line were up-regulated or not differentially expressed in the R line. The up-regulated DEGs in the R tomato line revealed the defense response of tomato to TYLCV infection was characterized by the induction and regulation of a series of genes involved in cell wall reorganization, transcriptional regulation, defense response, ubiquitination, metabolite synthesis and so on. The present study provides insights into various reactions underlining the successful establishment of resistance to TYLCV in the R tomato line, and helps in the identification of important defense-related genes in tomato for TYLCV disease management. PMID:24260487

  4. Virion stability is important for the circulative transmission of tomato yellow leaf curl sardinia virus by Bemisia tabaci, but virion access to salivary glands does not guarantee transmissibility.

    PubMed

    Caciagli, Piero; Medina Piles, Vicente; Marian, Daniele; Vecchiati, Manuela; Masenga, Vera; Mason, Giovanna; Falcioni, Tania; Noris, Emanuela

    2009-06-01

    The capsid protein (CP) of the monopartite begomovirus Tomato yellow leaf curl Sardinia virus (TYLCSV), family Geminiviridae, is indispensable for plant infection and vector transmission. A region between amino acids 129 and 152 is critical for virion assembly and insect transmissibility. Two previously described mutants, one with a double Q129P Q134H mutation (PNHD) and another with a further D152E change (PNHE), were found nontransmissible (NT). Another NT mutant with a single N130D change (QDQD) was retrieved from a new mutational analysis. In this study, these three NT mutants and the wild-type (wt) virus were compared in their relationships with the whitefly vector Bemisia tabaci and the nonvector Trialeurodes vaporariorum. Retention kinetics of NT mutants were analyzed by quantitative dot blot hybridization in whiteflies fed on infected plants. The QDQD mutant, whose virions appeared nongeminate following purification, was hardly detectable in either whitefly species at any sampling time. The PNHD mutant was acquired and circulated in both whitefly species for up to 10 days, like the wt virus, while PNHE circulated in B. tabaci only. Using immunogold labeling, both PNHD and PNHE CPs were detected in B. tabaci salivary glands (SGs) like the wt virus, while no labeling was found in any whitefly tissue with the QDQD mutant. Significant inhibition of transmission of the wt virus was observed after prior feeding of the insects on plants infected with the PNHE mutant, but not on plants infected with the other mutants. Virion stability and ability to cross the SG barrier are necessary for TYLCSV transmission, but interactions with molecular components inside the SGs are also critical for transmissibility.

  5. Molecular characterization of Citrus tatter leaf virus historically associated with Meyer lemon trees: complete genome sequence and development of biologically active in vitro transcripts.

    PubMed

    Tatineni, Satyanarayana; Afunian, Mohammad R; Hilf, Mark E; Gowda, Siddarame; Dawson, William O; Garnsey, Stephen M

    2009-04-01

    Citrus tatter leaf virus isolated from Meyer lemon trees (CTLV-ML) from California and Florida induces bud union incompatibility of citrus trees grafted on the widely used trifoliate and trifoliate hybrid rootstocks. The complete genome sequence of CTLV-ML was determined to be 6,495 nucleotides (nts), with two overlapping open reading frames (ORFs) and a poly (A) tail at the 3' end. The genome organization is similar to other capilloviruses, with ORF1 (nts 37 to 6,354) encoding a putative 242-kDa polyprotein which contains replication-associated domains plus a coat protein (CP), and ORF2 (nts 4,788 to 5,750), which is located within ORF1 in a different reading frame and encodes a putative movement protein. Although the proteins encoded by CTLV-ML possesses 84 to 96% amino acid sequence identity with strains of Apple stem grooving virus (ASGV), we observed two strikingly different regions in ORF1: variable region I (amino acids 532 to 570) and variable region II (amino acids 1,583 to 1,868), with only 15 to 18 and 56 to 62% identities, respectively, with the corresponding regions of ASGV strains. Conditions for a herbaceous systemic assay host were optimized in which the wild-type virus induced systemic infection in Phaseolus vulgaris cv. Light Red Kidney (LRK) bean plants at 19 or 22 degrees C but not at higher temperatures. In vitro transcripts generated from full-length cDNA clones induced systemic symptoms on LRK bean plants similar to that of the wild-type virus. Replication of the recombinant virus was confirmed by hybridization of a 5' positive-stranded RNA-specific probe to a genome-sized RNA and by reverse-transcription polymerase chain reaction.

  6. [Identification of Host Factors Interacting with the Movement Protein of Apple Chlorotic Leaf Spot Virus by Yeast Two-Hybrid System].

    PubMed

    He, Yikun; Zhong, Min; Zhang, Yu; Wang, Yanan; Cao, Keqiang

    2015-03-01

    In order to identify host factors which interact with the movement protein (MP) of Apple chlorotic leaf spot virus (ACLSV), ACLSV MP was cloned into the bait vector pGBKT7 and used to screen a cDNA library of Malus sylvestris cv. R12740-7A, which had previously been constructed by yeast two-hybrid sequencing transformation. The protein functions of the identified host factors were determined according to their gene annotations in GenBank. The result showed that the bait plasmid pGBKT7-MP showed no virulence or self-activating effect on yeast strain Y2H Gold. Sixty-nine interactor proteins were identified, which were divided into the following 10 classes according to their described functions: hydrolases; pathogenesis-related proteins; DNA binding proteins; phosphatases; ligases; proteins with catalytic activity; phenylalanine ammonialyases; peroxidases; NAD binding proteins; and proteins of unknown function. Bioinformatic analysis of gene homology suggested that phosphatases, pathogenesis-related proteins and glyceraldehyde-3-phosphate dehydrogenase A may play an important role in the interaction between virus and host. This study may provide a theoretical basis for the further study of viral pathogenesis and virus-host interaction mechanisms.

  7. Mapping quantitative trait loci of resistance to Tomato spotted wilt virus and leaf spots in a recombinant inbred line population of peanut (Arachis hypogae L.) from SunOleic 97R and NC94022

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut is vulnerable to a range of diseases, such as Tomato spotted wilt virus (TSWV) and leaf spots. The most sustainable and economical solution for managing peanut diseases is development of resistance cultivars. The new breeding line NC94022, high resistance to TSWV and moderate resistance to le...

  8. Development of a virus-induced gene-silencing system for hexaploid wheat and its use in functional analysis of the Lr21-mediated leaf rust resistance pathway.

    PubMed

    Scofield, Steven R; Huang, Li; Brandt, Amanda S; Gill, Bikram S

    2005-08-01

    Virus-induced gene silencing (VIGS) is an important tool for the analysis of gene function in plants. In VIGS, viruses engineered to carry sequences derived from plant gene transcripts activate the host's sequence-specific RNA degradation system. This mechanism targets the RNAs of the viral genome for degradation, and as the virus contains transcribed plant sequence, homologous host mRNAs are also targeted for destruction. While routinely used in some dicots, no VIGS system was known for monocot plants until the recent report of silencing in barley (Hordeum vulgare) by barley stripe mosaic virus (BSMV). Here, we report development of protocols for use of BSMV to efficiently silence genes in hexaploid wheat (Triticum aestivum). The VIGS system was first optimized in studies silencing phytoene desaturase expression. Next, we used it to assay genes functioning in leaf rust resistance mediated by Lr21, which encodes a nucleotide binding site-leucine-rich repeat class resistance gene product. We demonstrated that infection with BSMV constructs carrying a 150-bp fragment of Lr21 caused conversion of incompatible interactions to compatible, whereas infection with a control construct or one that silences phytoene desaturase had no effect on resistance or susceptibility. Additionally, silencing the RAR1, SGT1, and HSP90 genes, known to be required in many but not all nucleotide binding site-leucine-rich repeat resistance pathways in diverse plant species, resulted in conversion to compatibility, indicating that these genes are essential in Lr21-mediated resistance. These studies indicate that BSMV-VIGS is a powerful tool for dissecting the genetic pathways of disease resistance in hexaploid wheat.

  9. Precocious flowering of juvenile citrus induced by a viral vector based on Citrus leaf blotch virus: a new tool for genetics and breeding.

    PubMed

    Velázquez, Karelia; Agüero, Jesús; Vives, María C; Aleza, Pablo; Pina, José A; Moreno, Pedro; Navarro, Luis; Guerri, José

    2016-10-01

    The long juvenile period of citrus trees (often more than 6 years) has hindered genetic improvement by traditional breeding methods and genetic studies. In this work, we have developed a biotechnology tool to promote transition from the vegetative to the reproductive phase in juvenile citrus plants by expression of the Arabidopsis thaliana or citrus FLOWERING LOCUS T (FT) genes using a Citrus leaf blotch virus-based vector (clbvINpr-AtFT and clbvINpr-CiFT, respectively). Citrus plants of different genotypes graft inoculated with either of these vectors started flowering within 4-6 months, with no alteration of the plant architecture, leaf, flower or fruit morphology in comparison with noninoculated adult plants. The vector did not integrate in or recombine with the plant genome nor was it pollen or vector transmissible, albeit seed transmission at low rate was detected. The clbvINpr-AtFT is very stable, and flowering was observed over a period of at least 5 years. Precocious flowering of juvenile citrus plants after vector infection provides a helpful and safe tool to dramatically speed up genetic studies and breeding programmes.

  10. Precocious flowering of juvenile citrus induced by a viral vector based on Citrus leaf blotch virus: a new tool for genetics and breeding.

    PubMed

    Velázquez, Karelia; Agüero, Jesús; Vives, María C; Aleza, Pablo; Pina, José A; Moreno, Pedro; Navarro, Luis; Guerri, José

    2016-10-01

    The long juvenile period of citrus trees (often more than 6 years) has hindered genetic improvement by traditional breeding methods and genetic studies. In this work, we have developed a biotechnology tool to promote transition from the vegetative to the reproductive phase in juvenile citrus plants by expression of the Arabidopsis thaliana or citrus FLOWERING LOCUS T (FT) genes using a Citrus leaf blotch virus-based vector (clbvINpr-AtFT and clbvINpr-CiFT, respectively). Citrus plants of different genotypes graft inoculated with either of these vectors started flowering within 4-6 months, with no alteration of the plant architecture, leaf, flower or fruit morphology in comparison with noninoculated adult plants. The vector did not integrate in or recombine with the plant genome nor was it pollen or vector transmissible, albeit seed transmission at low rate was detected. The clbvINpr-AtFT is very stable, and flowering was observed over a period of at least 5 years. Precocious flowering of juvenile citrus plants after vector infection provides a helpful and safe tool to dramatically speed up genetic studies and breeding programmes. PMID:26920394

  11. The Whitefly Bemisia tabaci Knottin-1 Gene Is Implicated in Regulating the Quantity of Tomato Yellow Leaf Curl Virus Ingested and Transmitted by the Insect

    PubMed Central

    Hariton Shalev, Aliza; Sobol, Iris; Ghanim, Murad; Liu, Shu-Sheng; Czosnek, Henryk

    2016-01-01

    The whitefly Bemisia tabaci is a major pest to agricultural crops. It transmits begomoviruses, such as Tomato yellow leaf curl virus (TYLCV), in a circular, persistent fashion. Transcriptome analyses revealed that B. tabaci knottin genes were responsive to various stresses. Upon ingestion of tomato begomoviruses, two of the four knottin genes were upregulated, knot-1 (with the highest expression) and knot-3. In this study, we examined the involvement of B. tabaci knottin genes in relation to TYLCV circulative transmission. Knottins were silenced by feeding whiteflies with knottin dsRNA via detached tomato leaves. Large amounts of knot-1 transcripts were present in the abdomen of whiteflies, an obligatory transit site of begomoviruses in their circulative transmission pathway; knot-1 silencing significantly depleted the abdomen from knot-1 transcripts. Knot-1 silencing led to an increase in the amounts of TYLCV ingested by the insects and transmitted to tomato test plants by several orders of magnitude. This effect was not observed following knot-3 silencing. Hence, knot-1 plays a role in restricting the quantity of virions an insect may acquire and transmit. We suggest that knot-1 protects B. tabaci against deleterious effects caused by TYLCV by limiting the amount of virus associated with the whitefly vector. PMID:27455309

  12. The Tomato yellow leaf curl virus V2 protein forms aggregates depending on the cytoskeleton integrity and binds viral genomic DNA

    PubMed Central

    Moshe, Adi; Belausov, Eduard; Niehl, Annette; Heinlein, Manfred; Czosnek, Henryk; Gorovits, Rena

    2015-01-01

    The spread of Tomato yellow leaf curl virus (TYLCV) was accompanied by the formation of coat protein (CP) aggregates of increasing size in the cytoplasm and nucleus of infected tomato (Solanum lycopersicum) cells. In order to better understand the TYLCV-host interaction, we investigated the properties and the subcellular accumulation pattern of the non-structural viral protein V2. CP and V2 are the only sense-oriented genes on the virus circular single-stranded DNA genome. Similar to CP, V2 localized to cytoplasmic aggregates of increasing size and as infection progressed was also found in nuclei, where it co-localized with CP. V2 was associated with viral genomic DNA molecules, suggesting that V2 functions as a DNA shuttling protein. The formation and the 26S proteasome-mediated degradation of V2 aggregates were dependent on the integrity of the actin and microtubule cytoskeleton. We propose that the cytoskeleton-dependent formation and growth of V2 aggregates play an important role during TYLCV infection, and that microtubules and actin filaments are important for the delivery of V2 to the 26S proteasome. PMID:25940862

  13. The minimal sequence essential for replication and movement of Cotton leaf curl Multan betasatellite DNA by a helper virus in plant cells.

    PubMed

    Eini, Omid; Behjatnia, S A Akbar

    2016-10-01

    Betasatellites are single-stranded circular DNAs associated with a number of monopartite begomoviruses. Betasatellites rely on the helper begomoviruses for replication and movement in plant tissues and plant-to-plant transmission by vectors. Their genomes are approximately half the size of the helper viruses and consist of three main regions including the βC1 gene, an adenine-rich (A-rich) region, and the satellite conserved region (SCR). In this study, we investigated the minimal sequences required for Cotton leaf curl Multan betasatellite (CLCuMB) replication and movement. Mutational analysis of CLCuMB DNA genome indicated that βC1 gene and A-rich region were not required for trans-replication and movement of CLCuMB in host plants by a helper virus. Deletion of βC1 gene and a fragment (135 nt in length) upstream of this gene impaired CLCuMB replication. However, CLCuMB mutant with deletion of βC1 gene and a further 163 nucleotides replicated at a lower level as compared to the wild-type betasatellite. This suggests that there are essential elements in the fragment upstream of βC1 gene, which are required for the replication of CLCuMB rather than the size limitation of CLCuMB DNA. PMID:27193570

  14. Kinetics of interaction of Cotton Leaf Curl Kokhran Virus-Dabawali (CLCuKV-Dab) coat protein and its mutants with ssDNA

    SciTech Connect

    Priyadarshini, C.G. Poornima; Savithri, H.S.

    2009-04-10

    Gemini viral assembly and transport of viral DNA into nucleus for replication, essentially involve DNA-coat protein interactions. The kinetics of interaction of Cotton Leaf Curl Kokhran Virus-Dabawali recombinant coat protein (rCP) with DNA was studied by electrophoretic mobility shift assay (EMSA) and surface plasmon resonance (SPR). The rCP interacted with ssDNA with a K{sub A}, of 2.6 +- 0.29 x 10{sup 8} M{sup -1} in a sequence non-specific manner. The CP has a conserved C2H2 type zinc finger motif composed of residues C68, C72, H81 and H85. Mutation of these residues to alanine resulted in reduced binding to DNA probes. The H85A mutant rCP showed the least binding with approximately 756 fold loss in the association rate and a three order magnitude decrease in the binding affinity as compared to rCP. The CP-DNA interactions via the zinc finger motif could play a crucial role in virus assembly and in nuclear transport.

  15. The minimal sequence essential for replication and movement of Cotton leaf curl Multan betasatellite DNA by a helper virus in plant cells.

    PubMed

    Eini, Omid; Behjatnia, S A Akbar

    2016-10-01

    Betasatellites are single-stranded circular DNAs associated with a number of monopartite begomoviruses. Betasatellites rely on the helper begomoviruses for replication and movement in plant tissues and plant-to-plant transmission by vectors. Their genomes are approximately half the size of the helper viruses and consist of three main regions including the βC1 gene, an adenine-rich (A-rich) region, and the satellite conserved region (SCR). In this study, we investigated the minimal sequences required for Cotton leaf curl Multan betasatellite (CLCuMB) replication and movement. Mutational analysis of CLCuMB DNA genome indicated that βC1 gene and A-rich region were not required for trans-replication and movement of CLCuMB in host plants by a helper virus. Deletion of βC1 gene and a fragment (135 nt in length) upstream of this gene impaired CLCuMB replication. However, CLCuMB mutant with deletion of βC1 gene and a further 163 nucleotides replicated at a lower level as compared to the wild-type betasatellite. This suggests that there are essential elements in the fragment upstream of βC1 gene, which are required for the replication of CLCuMB rather than the size limitation of CLCuMB DNA.

  16. The Tomato yellow leaf curl virus V2 protein forms aggregates depending on the cytoskeleton integrity and binds viral genomic DNA.

    PubMed

    Moshe, Adi; Belausov, Eduard; Niehl, Annette; Heinlein, Manfred; Czosnek, Henryk; Gorovits, Rena

    2015-01-01

    The spread of Tomato yellow leaf curl virus (TYLCV) was accompanied by the formation of coat protein (CP) aggregates of increasing size in the cytoplasm and nucleus of infected tomato (Solanum lycopersicum) cells. In order to better understand the TYLCV-host interaction, we investigated the properties and the subcellular accumulation pattern of the non-structural viral protein V2. CP and V2 are the only sense-oriented genes on the virus circular single-stranded DNA genome. Similar to CP, V2 localized to cytoplasmic aggregates of increasing size and as infection progressed was also found in nuclei, where it co-localized with CP. V2 was associated with viral genomic DNA molecules, suggesting that V2 functions as a DNA shuttling protein. The formation and the 26S proteasome-mediated degradation of V2 aggregates were dependent on the integrity of the actin and microtubule cytoskeleton. We propose that the cytoskeleton-dependent formation and growth of V2 aggregates play an important role during TYLCV infection, and that microtubules and actin filaments are important for the delivery of V2 to the 26S proteasome. PMID:25940862

  17. The Whitefly Bemisia tabaci Knottin-1 Gene Is Implicated in Regulating the Quantity of Tomato Yellow Leaf Curl Virus Ingested and Transmitted by the Insect.

    PubMed

    Hariton Shalev, Aliza; Sobol, Iris; Ghanim, Murad; Liu, Shu-Sheng; Czosnek, Henryk

    2016-01-01

    The whitefly Bemisia tabaci is a major pest to agricultural crops. It transmits begomoviruses, such as Tomato yellow leaf curl virus (TYLCV), in a circular, persistent fashion. Transcriptome analyses revealed that B. tabaci knottin genes were responsive to various stresses. Upon ingestion of tomato begomoviruses, two of the four knottin genes were upregulated, knot-1 (with the highest expression) and knot-3. In this study, we examined the involvement of B. tabaci knottin genes in relation to TYLCV circulative transmission. Knottins were silenced by feeding whiteflies with knottin dsRNA via detached tomato leaves. Large amounts of knot-1 transcripts were present in the abdomen of whiteflies, an obligatory transit site of begomoviruses in their circulative transmission pathway; knot-1 silencing significantly depleted the abdomen from knot-1 transcripts. Knot-1 silencing led to an increase in the amounts of TYLCV ingested by the insects and transmitted to tomato test plants by several orders of magnitude. This effect was not observed following knot-3 silencing. Hence, knot-1 plays a role in restricting the quantity of virions an insect may acquire and transmit. We suggest that knot-1 protects B. tabaci against deleterious effects caused by TYLCV by limiting the amount of virus associated with the whitefly vector. PMID:27455309

  18. Rapid Construction of Stable Infectious Full-Length cDNA Clone of Papaya Leaf Distortion Mosaic Virus Using In-Fusion Cloning.

    PubMed

    Tuo, Decai; Shen, Wentao; Yan, Pu; Li, Xiaoying; Zhou, Peng

    2015-12-01

    Papaya leaf distortion mosaic virus (PLDMV) is becoming a threat to papaya and transgenic papaya resistant to the related pathogen, papaya ringspot virus (PRSV). The generation of infectious viral clones is an essential step for reverse-genetics studies of viral gene function and cross-protection. In this study, a sequence- and ligation-independent cloning system, the In-Fusion(®) Cloning Kit (Clontech, Mountain View, CA, USA), was used to construct intron-less or intron-containing full-length cDNA clones of the isolate PLDMV-DF, with the simultaneous scarless assembly of multiple viral and intron fragments into a plasmid vector in a single reaction. The intron-containing full-length cDNA clone of PLDMV-DF was stably propagated in Escherichia coli. In vitro intron-containing transcripts were processed and spliced into biologically active intron-less transcripts following mechanical inoculation and then initiated systemic infections in Carica papaya L. seedlings, which developed similar symptoms to those caused by the wild-type virus. However, no infectivity was detected when the plants were inoculated with RNA transcripts from the intron-less construct because the instability of the viral cDNA clone in bacterial cells caused a non-sense or deletion mutation of the genomic sequence of PLDMV-DF. To our knowledge, this is the first report of the construction of an infectious full-length cDNA clone of PLDMV and the splicing of intron-containing transcripts following mechanical inoculation. In-Fusion cloning shortens the construction time from months to days. Therefore, it is a faster, more flexible, and more efficient method than the traditional multistep restriction enzyme-mediated subcloning procedure. PMID:26633465

  19. Rapid Construction of Stable Infectious Full-Length cDNA Clone of Papaya Leaf Distortion Mosaic Virus Using In-Fusion Cloning.

    PubMed

    Tuo, Decai; Shen, Wentao; Yan, Pu; Li, Xiaoying; Zhou, Peng

    2015-12-01

    Papaya leaf distortion mosaic virus (PLDMV) is becoming a threat to papaya and transgenic papaya resistant to the related pathogen, papaya ringspot virus (PRSV). The generation of infectious viral clones is an essential step for reverse-genetics studies of viral gene function and cross-protection. In this study, a sequence- and ligation-independent cloning system, the In-Fusion(®) Cloning Kit (Clontech, Mountain View, CA, USA), was used to construct intron-less or intron-containing full-length cDNA clones of the isolate PLDMV-DF, with the simultaneous scarless assembly of multiple viral and intron fragments into a plasmid vector in a single reaction. The intron-containing full-length cDNA clone of PLDMV-DF was stably propagated in Escherichia coli. In vitro intron-containing transcripts were processed and spliced into biologically active intron-less transcripts following mechanical inoculation and then initiated systemic infections in Carica papaya L. seedlings, which developed similar symptoms to those caused by the wild-type virus. However, no infectivity was detected when the plants were inoculated with RNA transcripts from the intron-less construct because the instability of the viral cDNA clone in bacterial cells caused a non-sense or deletion mutation of the genomic sequence of PLDMV-DF. To our knowledge, this is the first report of the construction of an infectious full-length cDNA clone of PLDMV and the splicing of intron-containing transcripts following mechanical inoculation. In-Fusion cloning shortens the construction time from months to days. Therefore, it is a faster, more flexible, and more efficient method than the traditional multistep restriction enzyme-mediated subcloning procedure.

  20. Rapid Construction of Stable Infectious Full-Length cDNA Clone of Papaya Leaf Distortion Mosaic Virus Using In-Fusion Cloning

    PubMed Central

    Tuo, Decai; Shen, Wentao; Yan, Pu; Li, Xiaoying; Zhou, Peng

    2015-01-01

    Papaya leaf distortion mosaic virus (PLDMV) is becoming a threat to papaya and transgenic papaya resistant to the related pathogen, papaya ringspot virus (PRSV). The generation of infectious viral clones is an essential step for reverse-genetics studies of viral gene function and cross-protection. In this study, a sequence- and ligation-independent cloning system, the In-Fusion® Cloning Kit (Clontech, Mountain View, CA, USA), was used to construct intron-less or intron-containing full-length cDNA clones of the isolate PLDMV-DF, with the simultaneous scarless assembly of multiple viral and intron fragments into a plasmid vector in a single reaction. The intron-containing full-length cDNA clone of PLDMV-DF was stably propagated in Escherichia coli. In vitro intron-containing transcripts were processed and spliced into biologically active intron-less transcripts following mechanical inoculation and then initiated systemic infections in Carica papaya L. seedlings, which developed similar symptoms to those caused by the wild-type virus. However, no infectivity was detected when the plants were inoculated with RNA transcripts from the intron-less construct because the instability of the viral cDNA clone in bacterial cells caused a non-sense or deletion mutation of the genomic sequence of PLDMV-DF. To our knowledge, this is the first report of the construction of an infectious full-length cDNA clone of PLDMV and the splicing of intron-containing transcripts following mechanical inoculation. In-Fusion cloning shortens the construction time from months to days. Therefore, it is a faster, more flexible, and more efficient method than the traditional multistep restriction enzyme-mediated subcloning procedure. PMID:26633465

  1. Silk gland gene expression during larval-pupal transitionin the cotton leaf roller Sylepta derogate (Lepidoptera: pyralidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cotton leaf roller, Sylepta derogata, is a silk-producing insect pest. While young larvae feed on the underside of leaves, the older ones roll cotton leaves and feed on the leaf edges, which defoliates cotton plants. The larvae produce silk to stabilize the rolled leaf and to balloon from used t...

  2. Comparative transcriptome analysis in Bemisia tabaci in response to tomato yellow leaf curl virus and development of ribonucleic acid interference to manage whitefly-transmitted viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The whitefly, Bemisia tabaci transmits over 300 plant viruses, with the majority of them belonging to the Begomovirus genus. Begomoviruses are obligately transmitted to a wide range of agriculture crops, resulting in the loss of billions of dollars annually, while jeopardizing food security worldwid...

  3. Transcriptome analysis of Bemisia tabaci during tomato yellow leaf curl virus acquisition and ribonucleic acid interference to manage whitefly-transmitted viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 300 viruses are transmitted by the whitefly, Bemisia tabaci, with 90% of them belonging to the genus, Begomovirus. Begomoviruses are obligately transmitted by whiteflies to a wide range of agriculture crops, resulting in billions of dollars lost annually, while jeopardizing food security worldw...

  4. Infection of tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus with betasatellites, results in enhanced level of helper virus components and antagonistic interaction between DNA B and betasatellites.

    PubMed

    Jyothsna, P; Haq, Q M I; Singh, Priyanka; Sumiya, K V; Praveen, Shelly; Rawat, Ramaveer; Briddon, Rob W; Malathi, V G

    2013-06-01

    Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003-2010 to study the diversity of begomoviruses found in tomato, potato, and cucurbits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten begomovirus isolates were cloned from infected samples and identified as belonging to the species ToLCNDV. A total of 44 % of the samples showed association of betasatellites, with CLCuMuB and LuLDB being the most frequent. The ToLCNDV cloned component DNA A and DNA B were agroinoculated on Nicotiana benthamiana and tomato (Solanum lycopersicum) plants with or without betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored by real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with betasatellites showed enhanced symptom severity in both N. benthamiana and tomato, as well as increases in helper viral DNA A and DNA B levels. The DNA B and betasatellites acted antagonistically to each other, so that the level of DNA B was 16-fold greater in the presence of betasatellites, while accumulation of betasatellites, CLCuMuB and LuLDB, were reduced by 60 % in the presence of DNA B. DNA B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas betasatellite-mediated leaf abnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will be a good biotechnological tool in resistance breeding program. PMID:23306645

  5. Yellowing disease in zucchini squash produced by mixed infections of Cucurbit yellow stunting disorder virus and Cucumber vein yellowing virus.

    PubMed

    Gil-Salas, Francisco M; Peters, Jeff; Boonham, Neil; Cuadrado, Isabel M; Janssen, Dirk

    2011-11-01

    Zucchini squash is host to Cucurbit yellow stunting disorder virus (CYSDV), a member of the genus Crinivirus, and Cucumber vein yellowing virus (CVYV), a member of the genus Ipomovirus, both transmitted by the whitefly Bemisia tabaci. Field observations suggest the appearance of new symptoms observed on leaves of zucchini squash crops when both viruses were present. When infected during controlled experiments with CYSDV only, zucchini plants showed no obvious symptoms and the virus titer decreased between 15 and 45 days postinoculation (dpi), after which it was no longer detected. CVYV caused inconspicuous symptoms restricted to vein clearing on some of the apical leaves and the virus accumulated progressively between 15 and 60 dpi. Similar accumulations of virus followed single inoculations with the potyvirus Zucchini yellow mosaic virus (ZYMV) and plants showed severe stunting, leaf deformation, and mosaic yellowing. However, in mixed infections with CYSDV and CVYV, intermediate leaves showed chlorotic mottling which evolved later to rolling, brittleness, and complete yellowing of the leaf lamina, with exception of the veins. No consistent alteration of CVYV accumulation was detected but the amounts of CYSDV increased ≈100-fold and remained detectable at 60 dpi. Such synergistic effects on the titer of the crinivirus and symptom expression were not observed when co-infected with ZYMV.

  6. Molecular evolutionary history of Sugarcane yellow leaf virus based on sequence analysis of RNA-dependent RNA polymerase and putative aphid transmission factor-coding genes.

    PubMed

    ElSayed, Abdelaleim Ismail; Boulila, Moncef; Rott, Philippe

    2014-06-01

    RNA-dependent RNA polymerase (RdRp) encoded by ORF2 and putative aphid transmission factor (PATF) encoded by ORF5 of Sugarcane yellow leaf virus (SCYLV) were detected in six sugarcane cultivars affected by yellow leaf using RT-PCR and real-time RT-PCR assays. Expression of both genes varied among infected plants, but overall expression of RdRp was higher than expression of PATF. Cultivar H87-4094 from Hawaii yielded the highest transcript levels of RdRp, whereas cultivar C1051-73 from Cuba exhibited the lowest levels. Sequence comparisons among 25 SCYLV isolates from various geographical locations revealed an amino acid similarity of 72.1-99.4 and 84.7-99.8 % for the RdRp and PATF genes, respectively. The 25 SCYLV isolates were separated into three (RdRp) and two (PATF) phylogenetic groups using the MEGA6 program that does not account for genetic recombination. However, the SCYLV genome contained potential recombination signals in the RdRp and PATF coding genes based on the GARD genetic algorithm. Use of this later program resulted in the reconstruction of phylogenies on the left as well as on the right sides of the putative recombination breaking points, and the 25 SCYLV isolates were distributed into three distinct phylogenetic groups based on either RdRp or PATF sequences. As a result, recombination reshuffled the affiliation of the accessions to the different clusters. Analysis of selection pressures exerted on RdRp and PATF encoded proteins revealed that ORF 2 and ORF 5 underwent predominantly purifying selection. However, a few sites were also under positive selection as assessed by various models such as FEL, IFEL, REL, FUBAR, MEME, GA-Branch, and PRIME. PMID:24952671

  7. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  8. Preference by a virus vector for infected plants is reversed after virus acquisition.

    PubMed

    Rajabaskar, Dheivasigamani; Bosque-Pérez, Nilsa A; Eigenbrode, Sanford D

    2014-06-24

    Pathogens and their vectors can interact either directly or indirectly via their shared hosts, with implications for the persistence and spread of the pathogen in host populations. For example, some plant viruses induce changes in host plants that cause the aphids that carry these viruses to settle preferentially on infected plants. Furthermore, relative preference by the vector for infected plants can change to a preference for noninfected plants after virus acquisition by the vector, as has recently been demonstrated in the wheat-Rhopalosiphum padi-Barley yellow dwarf virus pathosystem. Here we document a similar dynamic in the potato-Myzus persicae (Sulzer)-Potato leaf roll virus (PLRV) pathosystem. Specifically, in a dual choice bioassay, nonviruliferous apterous M. persicae settled preferentially on or near potato plants infected with PLRV relative to noninfected (sham-inoculated) control plants, whereas viruliferous M. persicae (carrying PLRV) preferentially settled on or near sham-inoculated potato plants relative to infected plants. The change in preference after virus acquisition also occurred in response to trapped headspace volatiles, and to synthetic mimics of headspace volatile blends from PLRV-infected and sham-inoculated potato plants. The change in preference we document should promote virus spread by increasing rates of virus acquisition and transmission by the vector. PMID:24269348

  9. Differential response of diverse solanaceous hosts to tomato leaf curl New Delhi virus infection indicates coordinated action of NBS-LRR and RNAi-mediated host defense.

    PubMed

    Kushwaha, Nirbhay; Singh, Ashish Kumar; Basu, Saumik; Chakraborty, Supriya

    2015-06-01

    Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) that infects a wide range of plants. ToLCNDV has emerged as an important pathogen and a serious threat to tomato production in India. A comparative and molecular analysis of ToLCNDV pathogenesis was performed on diverse solanaceous hosts (Capsicum annuum, Nicotiana benthamiana, N. tabacum, and Solanum lycopersicum). N. benthamiana was found to be the most susceptible host, whereas C. annuum showed resistance against an isolate of ToLCNDV collected in New Delhi from tomato (GenBank accession no. U15015 and U15017). S. lycopersicum and N. tabacum developed conspicuous symptoms and allowed virus to accumulate to significantly high titers. The viral DNA level was concurrent with symptom severity. ToLCNDV-specific siRNA levels were directly proportional to the amount of viral DNA. To investigate the basis for the differences in response of these hosts to ToLCNDV, a comparative expression analysis of selected defense-related genes was carried out. The results indicated differences in expression levels of genes involved in the posttranscriptional gene silencing machinery (RDR6, AGO1 and SGS3) as well as basal host defense responses (nucleotide-binding site and leucine-rich repeat [NBS-LRR] proteins and lipid transfer protein [LTP]). Among these, expression of NBS-LRR genes was found to be significantly higher in C. annuum following ToLCNDV infection. Our analyses suggest that the expression of host defense responses determines the level of ToLCNDV accumulation and degree of symptom development.

  10. Putative recombination signature and significance of insertion/deletion events in the RNA-dependent RNA polymerase coding region of sugarcane yellow leaf virus.

    PubMed

    ElSayed, Abdelaleim Ismail; Boulila, Moncef; Komor, Ewald; Zhu, Yun J

    2012-08-01

    The 5898 nucleotide single-strand RNA genome of Sugarcane yellow leaf virus (SCYLV) contains one long open reading frame, which is translated into a 120.6 kDa polyprotein. The sequences of SCYLV isolates from the two SCYLV-susceptible cultivars from Hawaii had a deletion of 48-51 nt in ORF1. SCYLV from 12 sugarcane hybrid cultivars from different origins were tested by RT-PCR using a specific set of primers, to investigate the genome segment for this deletion. Only three cultivars were found not to have the deletion (H87-4319, JA-605 and CP52-43), while SCYLV from nine cultivars (H73-6110, H87-4094, H78-7750, GT54-9, G84-47, H78-4153, H65-7052, C1051-73, Ph-8013) along with aphid (Melanaphis sacchari), which fed on SCYLV-infected H73-6110, contained a deletion of about 50 nt. The deleted sequence was located in the overlap frameshift of ORF1 and ORF2. Thus, ORFs 1 and 2 of SCYLV are translated via ribosomal frameshift and yield the 120.6 kDa viral replicase. ORF1 plays most likely a role in the replication and is a source of large variability among the virus population. To identify possible recombination events located in the RdRp domain of the Hawaiian isolates, two programs were used: RDP v.4.3 and RECCO. It is noteworthy that according both methods Haw73-6110 was found as a potential recombinant. On the other hand, opposed to the RDP package, RECCO revealed that Haw87-4094 isolate was also a recombinant whereas Haw87-4319 was not. PMID:22542996

  11. Comparative Analyses of Tomato yellow leaf curl virus C4 Protein-Interacting Host Proteins in Healthy and Infected Tomato Tissues

    PubMed Central

    Kim, Namgyu; Kim, Jinnyun; Bang, Bongjun; Kim, Inyoung; Lee, Hyun-Hee; Park, Jungwook; Seo, Young-Su

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins—two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein—were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection. PMID:27721687

  12. Molecular characterization of a new begomovirus associated with leaf yellow mosaic disease of Jatropha curcas in India.

    PubMed

    Srivastava, Ashish; Kumar, S; Jaidi, Meraj; Raj, S K

    2015-05-01

    During a survey in June 2011, severe leaf yellow mosaic disease was observed on about 45 % plants of Jatropha curcas growing in the Katerniaghat wildlife sanctuary in India. An association of a begomovirus with disease was detected in 15 out of 20 samples by PCR using begomovirus genus-specific primers and total DNA isolated from symptomatic leaf samples. For identification of the begomovirus, the complete genome was amplified using a Phi-29 DNA-polymerase-based rolling-circle amplification kit and total DNA from five representative samples and then digested with BamHI. The linearized RCA products were cloned and sequenced. Their GenBank accession numbers are JN698954 (SKRK1) and JN135236 (SKRK2). The sequences of the two begomovirus isolates were 97 % identical to each other and no more than 86 % to those of jatropha mosaic India virus (JMIV, HM230683) and other begomoviruses reported worldwide. In phylogenetic analysis, SKRK1 and SKRK2 clustered together and showed distant relationships to jatropha mosaic India virus, Jatropha curcas mosaic virus, Indian cassava mosaic virus, Sri Lankan cassava mosaic virus and other begomoviruses. Based on 86 % sequence identities and distant phylogenetic relationships to JMIV and other begomoviruses and the begomovirus species demarcation criteria of the ICTV (<89 % sequence identity of complete DNA-A genome), the begomovirus isolates associated with leaf yellow mosaic disease of J. curcas were identified as members of a new begomovirus species and provisionally designated as jatropha leaf yellow mosaic Katerniaghat virus (JLYMKV). Agroinfectious clones of the DNA molecule of the begomovirus isolate were also generated, and the fulfillment of Koch's postulates was demonstrated in J. curcas plants. PMID:25716923

  13. Molecular characterization of a new begomovirus associated with leaf yellow mosaic disease of Jatropha curcas in India.

    PubMed

    Srivastava, Ashish; Kumar, S; Jaidi, Meraj; Raj, S K

    2015-05-01

    During a survey in June 2011, severe leaf yellow mosaic disease was observed on about 45 % plants of Jatropha curcas growing in the Katerniaghat wildlife sanctuary in India. An association of a begomovirus with disease was detected in 15 out of 20 samples by PCR using begomovirus genus-specific primers and total DNA isolated from symptomatic leaf samples. For identification of the begomovirus, the complete genome was amplified using a Phi-29 DNA-polymerase-based rolling-circle amplification kit and total DNA from five representative samples and then digested with BamHI. The linearized RCA products were cloned and sequenced. Their GenBank accession numbers are JN698954 (SKRK1) and JN135236 (SKRK2). The sequences of the two begomovirus isolates were 97 % identical to each other and no more than 86 % to those of jatropha mosaic India virus (JMIV, HM230683) and other begomoviruses reported worldwide. In phylogenetic analysis, SKRK1 and SKRK2 clustered together and showed distant relationships to jatropha mosaic India virus, Jatropha curcas mosaic virus, Indian cassava mosaic virus, Sri Lankan cassava mosaic virus and other begomoviruses. Based on 86 % sequence identities and distant phylogenetic relationships to JMIV and other begomoviruses and the begomovirus species demarcation criteria of the ICTV (<89 % sequence identity of complete DNA-A genome), the begomovirus isolates associated with leaf yellow mosaic disease of J. curcas were identified as members of a new begomovirus species and provisionally designated as jatropha leaf yellow mosaic Katerniaghat virus (JLYMKV). Agroinfectious clones of the DNA molecule of the begomovirus isolate were also generated, and the fulfillment of Koch's postulates was demonstrated in J. curcas plants.

  14. Chilli leaf curl virus infection highlights the differential expression of genes involved in protein homeostasis and defense in resistant chilli plants.

    PubMed

    Kushwaha, Nirbhay; Sahu, Pranav Pankaj; Prasad, Manoj; Chakraborty, Supriya

    2015-06-01

    Geminiviruses have evolved with tremendous potential of recombination and possess the ability to manipulate several cellular processes of hosts. Chilli leaf curl virus (ChiLCV) is a monopartite Begomovirus (family Geminiviridae) which has emerged as a serious threat to chilli production worldwide. To date, development of resistant chilli varieties through conventional plant breeding techniques remains the major antiviral strategy. To explore the potential resistance factors in Capsicum annuum var. Punjab Lal, we performed a transcriptome analysis in ChiLCV-infected plants by exploiting the advantage of sensitivity and efficiency of suppression subtractive hybridization (SSH). Out of 480 clones screened, 231 unique expressed sequence tags (ESTs) involved in different cellular and physiological processes were identified. An interactome network of ChiLCV responsive differentially expressed genes revealed an array of proteins involved in key cellular processes including transcription, replication, photosynthesis, and defense. A comparative study of gene expression between resistant and susceptible chilli plants revealed upregulation of several defense-related genes such as nucleotide-binding site leucine-rich repeat (NBS-LRR) domain containing protein, lipid transfer protein, thionin, polyphenol oxidase, and other proteins like ATP/ADP transporter in the ChiLCV-resistant variety. Taken together, the present study provides novel insights into the transcriptomics of ChiLCV-resistant chilli plants.

  15. The Cucumber leaf spot virus p25 auxiliary replicase protein binds and modifies the endoplasmic reticulum via N-terminal transmembrane domains

    SciTech Connect

    Ghoshal, Kankana; Theilmann, Jane; Reade, Ron; Sanfacon, Helene; Rochon, D’Ann

    2014-11-15

    Cucumber leaf spot virus (CLSV) is a member of the Aureusvirus genus, family Tombusviridae. The auxiliary replicase of Tombusvirids has been found to localize to endoplasmic reticulum (ER), peroxisomes or mitochondria; however, localization of the auxiliary replicase of aureusviruses has not been determined. We have found that the auxiliary replicase of CLSV (p25) fused to GFP colocalizes with ER and that three predicted transmembrane domains (TMDs) at the N-terminus of p25 are sufficient for targeting, although the second and third TMDs play the most prominent roles. Confocal analysis of CLSV infected 16C plants shows that the ER becomes modified including the formation of punctae at connections between ER tubules and in association with the nucleus. Ultrastructural analysis shows that the cytoplasm contains numerous vesicles which are also found between the perinuclear ER and nuclear membrane. It is proposed that these vesicles correspond to modified ER used as sites for CLSV replication. - Highlights: • The CLSV p25 auxiliary replicase targets the endoplasmic reticulum (ER). • Targeting of CLSV p25 is associated with ER restructuring. • Restructuring of the ER occurs during CLSV infection. • CLSV p25 contains 3 predicted transmembrane domains 2 of which are required for ER targeting. • Vesicles derived from the ER may be sites of CLSV replication.

  16. Transferring cucumber mosaic virus-white leaf strain coat protein gene into Cucumis melo L. and evaluating transgenic plants for protection against infections

    SciTech Connect

    Gonsalves, C.; Xue, B.; Yepes, M.; Fuchs, M.; Ling, K.; Namba, S. . Dept. of Plant Pathology)

    1994-03-01

    A single regeneration procedure using cotyledon examples effectively regenerated five commercially grown muskmelon cultivars. This regeneration scheme was used to facilitate gene transfers using either Agrobacterium tumefaciens or microprojectile bombardment methods. In both cases, the transferred genes were from the T-DNA region of the binary vector plasmid pGA482GG/cp cucumber mosaic virus-white leaf strain (CMV-WL), which contains genes that encode neomycin phosphotransferase II (NPT II), [beta]-glucuronidase (GUS), and the CMV-WL coat protein (CP). Explants treated with pGA482GG/cpCMV-WL regenerated shoots on Murashige and Skoog medium containing 4.4 [mu]m 6-benzylaminopurine (BA), kanamycin (Km) at 150 mg[center dot]liter[sup [minus]1] and carbenicillin (Cb) at 500 mg[center dot]liter[sup [minus]1]. The authors' comparison of A. tumefaciens- and microprojectile-mediated gene transfer procedures shows that both methods effectively produce nearly the same percentage of transgenic plants. R[sub 0] plants were first tested for GUS or NPT II expression, then the polymerase chain reaction (PCR) and other tests were used to verify the transfer of the NPT II, GUS, and CMV-WL CP genes.

  17. Effectiveness of Cyantraniliprole for Managing Bemisia tabaci (Hemiptera: Aleyrodidae) and Interfering with Transmission of Tomato Yellow Leaf Curl Virus on Tomato.

    PubMed

    Caballero, Rafael; Schuster, David J; Peres, Natalia A; Mangandi, Jozer; Hasing, Tomas; Trexler, Fred; Kalb, Steve; Portillo, Héctor E; Marçon, Paula C; Annan, I B

    2015-06-01

    Cyantraniliprole is the second xylem-systemic active ingredient in the new anthranilic diamide class. Greenhouse (2006), growth chamber (2007), and field studies (2009-2010) were conducted to determine the efficacy of cyantraniliprole for managing Bemisia tabaci (Gennadius) biotype B and in interfering with transmission of tomato yellow leaf curl virus (TYLCV) by this whitefly. Cyantraniliprole applied as soil treatments (200 SC) or foliar sprays (100 OD) provided excellent adult whitefly control, TYLCV suppression, and reduced oviposition and nymph survival, comparable to current standards. The positive results observed in these greenhouse experiments with a high level of insect pressure (10× the field threshold of one adult per plant) and disease pressure (five adults per plant, with a high level of confidence that TYLCV virulent adults were used), indicate a great potential for cyantraniliprole to be used in a whitefly management program. Field evaluations of soil drench treatments confirmed the suppression of TYLCV transmission demonstrated in the greenhouse studies. Field studies in 2009 and 2010 showed that cyantraniliprole (200 SC) provided TYLCV suppression for 2 wk after a drench application, when using a susceptible (2009) or imidacloprid-tolerant (2010) whitefly population. Cyantraniliprole was demonstrated to be a promising tool for management of TYLCV in tomato production, which is very difficult and expensive, and which has limited options. The integration of cyantraniliprole into a resistance management program will help to ensure the continued sustainability of this and current insecticides used for the management of insect vectors, including whiteflies and the TYLCV they spreads. PMID:26470209

  18. Whitefly population dynamics and evaluation of whitefly-transmitted tomato yellow leaf curl virus (TYLCV)-resistant tomato genotypes as whitefly and TYLCV reservoirs.

    PubMed

    Srinivasan, Rajagopalbabu; Riley, David; Diffie, Stan; Sparks, Alton; Adkins, Scott

    2012-08-01

    Sweetpotato whitefly, Bemisia tabaci (Gennadius), and whitefly-transmitted tomato yellow leaf curl virus (TYLCV) are major threats to tomato production in the southeastern United States. TYLCV was introduced to Florida from the Caribbean islands and has spread to other southern states of the United States. In Georgia, in recent years, the incidence of TYLCV has been steadily increasing. Studies were conducted to monitor population dynamics of whiteflies in the vegetable production belt of Georgia, to evaluate TYLCV-resistant genotypes against whiteflies and TYLCV, and to assess the potential role of resistant genotypes in TYLCV epidemiology. Monitoring studies indicated that the peak incidence of whiteflies varied seasonally from year to year. In general, whitefly populations were not uniformly distributed. Tomato genotypes exhibited minor differences in their ability to support whitefly populations. TYLCV symptoms were visually undetectable in all but one resistant genotype. The infection rates (visually) in susceptible genotypes ranged from 40 to 87%. Greenhouse inoculations with viruliferous whiteflies followed by polymerase chain reaction (PCR) indicated that up to 100% of plants of resistant genotypes were infected, although predominantly symptomless. TYLCV acquisition by whiteflies from TYLCV-infected genotypes was tested by PCR; TYLCV acquisition rates from resistant genotypes were less than from susceptible genotypes. Nevertheless, this difference did not influence TYLCV transmission rates from resistant to susceptible genotypes. Results emphasize that resistant genotypes can serve as TYLCV and whitefly reservoirs and potentially influence TYLCV epidemics. PMID:22928328

  19. Chilli leaf curl virus infection highlights the differential expression of genes involved in protein homeostasis and defense in resistant chilli plants.

    PubMed

    Kushwaha, Nirbhay; Sahu, Pranav Pankaj; Prasad, Manoj; Chakraborty, Supriya

    2015-06-01

    Geminiviruses have evolved with tremendous potential of recombination and possess the ability to manipulate several cellular processes of hosts. Chilli leaf curl virus (ChiLCV) is a monopartite Begomovirus (family Geminiviridae) which has emerged as a serious threat to chilli production worldwide. To date, development of resistant chilli varieties through conventional plant breeding techniques remains the major antiviral strategy. To explore the potential resistance factors in Capsicum annuum var. Punjab Lal, we performed a transcriptome analysis in ChiLCV-infected plants by exploiting the advantage of sensitivity and efficiency of suppression subtractive hybridization (SSH). Out of 480 clones screened, 231 unique expressed sequence tags (ESTs) involved in different cellular and physiological processes were identified. An interactome network of ChiLCV responsive differentially expressed genes revealed an array of proteins involved in key cellular processes including transcription, replication, photosynthesis, and defense. A comparative study of gene expression between resistant and susceptible chilli plants revealed upregulation of several defense-related genes such as nucleotide-binding site leucine-rich repeat (NBS-LRR) domain containing protein, lipid transfer protein, thionin, polyphenol oxidase, and other proteins like ATP/ADP transporter in the ChiLCV-resistant variety. Taken together, the present study provides novel insights into the transcriptomics of ChiLCV-resistant chilli plants. PMID:25693670

  20. Complete nucleotide sequences of the genomes of two isolates of apple chlorotic leaf spot virus from peach (Prunus persica) in China.

    PubMed

    Niu, Feiqing; Pan, Song; Wu, Zujian; Jiang, Dongmei; Li, Shifang

    2012-04-01

    The complete nucleotide sequences of two isolates of apple chlorotic leaf spot virus (Z1 and Z3) collected from peach in Henan Province, China, were determined. The genomes of both Z1 and Z3 were found to contain three open reading frames (ORFs). Sequence analysis showed that genomic sequences of Z1 and Z3 isolates shared 67.4%-82.9% and 67.2%-82.6% identity, respectively, with the other eight isolates of ACLSV that have been reported previously. Based on the putative amino acid sequences of the products of the three ORFs, Z1 and Z3 isolates showed the greatest identity to isolate PBM1 (GenBank accession number AJ243438) from plum and the least identity with isolate Ta Tao5 (GenBank Accession Number: EU223295) from peach. Considering the low level of sequence identity between Z1/Z3 isolate and Ta Tao5 isolate, two types of ACLSV may exist in peach.

  1. PCR-RFLP-based typing for differentiation of Tomato yellow leaf curl virus (TYLCV) genotypes from infected host plants in Korea.

    PubMed

    Oh, Sung; Kim, Seongdae; Vinod, Nagarajan; Koo, Jung Mo; Jang, Kyung Min; Choi, Chang Won; Kim, Seong Hwan; Kim, Young Shik

    2013-12-01

    A polymerase chain reaction (PCR) using two sets of primers designed from published Tomato yellow leaf curl virus (TYLCV) genomes was developed to distinguish from the TYLCV-IL groups. The specificity of the two sets of primers was proven by testing against control TYLCV genomes and the symptomatic leaves of 34 different tomato cultivars naturally infected with TYLCV in greenhouses. One set for TYLCV-IL strain-specific primers (TYLCV-UNI-F and TYLCV-UNI-R) amplified full-length genome fragments from all the 34 tomato cultivars. Another set for TYLCV-IL group-II strain-specific primers (TYLCV-GPII-F and TYLCV-GPII-R) amplified target DNA fragments from only 9 tomato cultivars. Digestion by BglII and EcoRV of the PCR amplicons produced restriction fragment length polymorphism pattern that distinguished the TYLCV-IL group-I with two fragments from the TYLCV-IL group-II with no digested fragment. PCR coupled with BglII and EcoRV digestion confirmed that the 9 tomato cultivars were infected with the TYLCV-IL group-II and the remained 25 tomato cultivars were infected with the TYLCV-IL group-I. PMID:23884784

  2. The RT-PCR identification and sequence analysis of Apple chlorotic leaf spot virus from apple cultivars in Jiaodong Peninsula, China

    PubMed Central

    Hu, Dechang; Wang, Lei; Jiang, Xiaoman; Wang, Ning; Gu, Liang

    2014-01-01

    A set of specific primer pairs was utilized to detect Apple chlorotic leaf spot virus (ACLSV) from seven different apple cultivars in Jiaodong Peninsula via reverse transcription polymerase chain reaction (RT-PCR), and the sequence of ACLSV genome was analysed. The results indicate that: (1) High-purity total RNA could be successfully isolated using plant RNA rapid extraction kit. The ratios of A260/A280 varied between 1.8 and 2.1. The fragmentation in agarose gel was good and the 28S and 16S bands were clear, which suggested that the extracted RNA had better quality and could be used for RT-PCR. (2) The amplified products by RT-PCR were approximately 220 bp, which showed the tested samples were infected by ACLSV in this study. (3) Sequencing analysis showed that the lengths of the target fragments were 217 bp, and the sequence identity rate ranged from 85.7% to 99.1% at the nucleotide level aligned with the corresponding sequences of other ACLSV strains in National Center for Biotechnology Information. PMID:26019509

  3. The presence of tomato leaf curl Kerala virus AC3 protein enhances viral DNA replication and modulates virus induced gene-silencing mechanism in tomato plants

    PubMed Central

    2011-01-01

    Background Geminiviruses encode few viral proteins. Most of the geminiviral proteins are multifunctional and influence various host cellular processes for the successful viral infection. Though few viral proteins like AC1 and AC2 are well characterized for their multiple functions, role of AC3 in the successful viral infection has not been investigated in detail. Results We performed phage display analysis with the purified recombinant AC3 protein with Maltose Binding Protein as fusion tag (MBP-AC3). Putative AC3 interacting peptides identified through phage display were observed to be homologous to peptides of proteins from various metabolisms. We grouped these putative AC3 interacting peptides according to the known metabolic function of the homologous peptide containing proteins. In order to check if AC3 influences any of these particular metabolic pathways, we designed vectors for assaying DNA replication and virus induced gene-silencing of host gene PCNA. Investigation with these vectors indicated that AC3 enhances viral replication in the host plant tomato. In the PCNA gene-silencing experiment, we observed that the presence of functional AC3 ORF strongly manifested the stunted phenotype associated with the virus induced gene-silencing of PCNA in tomato plants. Conclusions Through the phage display analysis proteins from various metabolic pathways were identified as putative AC3 interacting proteins. By utilizing the vectors developed, we could analyze the role of AC3 in viral DNA replication and host gene-silencing. Our studies indicate that AC3 is also a multifunctional protein. PMID:21496351

  4. WORK ROLLS AND BACKUP ROLLS FROM #43 AND #44 MILLS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WORK ROLLS AND BACKUP ROLLS FROM #43 AND #44 MILLS AWAIT DRESSING IN ROLL GRINDER. ROLL SHOP OPERATIONS, INCLUDING REPAIR, CLEANING AND GREASING, ARE HOUSED IN THE REROLL BAY. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  5. Impact of aphid alarm pheromone release on virus transmission efficiency: When pest control strategy could induce higher virus dispersion.

    PubMed

    Lin, Fang-Jing; Bosquée, Emilie; Liu, Ying-Jie; Chen, Ju-Lian; Yong, Liu; Francis, Frédéric

    2016-09-01

    Aphids cause serious damages to crops not only by tacking sap but also by transmitting numerous viruses. To develop biological control, the aphid alarm pheromone, namely E-β-farnesene (EβF), has been demonstrated to be efficient to repel aphids and as attract beneficials, making it a potential tool to control aphid pests. Considering aphids also as virus vectors, changes of their behavior could also interfere with the virus acquisition and transmission process. Here, a combination of two aphid species and two potato virus models were selected to test the influence of EβF release on aphid and virus dispersion under laboratory conditions. EβF release was found to significantly decrease the population of Myzus persicae and Macrosiphum euphorbiae around the infochemical releaser but simultaneously also increasing the dispersal of Potato Virus Y (PVY). At the opposite, no significant difference for Potato Leaf Roll Virus (PLRV) transmission efficiency was observed with similar aphid alarm pheromone releases for none of the aphid species. These results provide some support to carefully consider infochemical releasers not only for push-pull strategy and pest control but also to include viral disease in a the plant protection to aphids as they are also efficient virus vectors. Impact of aphid kinds and transmission mechanisms will be discussed according to the large variation found between persistent and non persistent potato viruses and interactions with aphids and related infochemicals. PMID:27185564

  6. Impact of aphid alarm pheromone release on virus transmission efficiency: When pest control strategy could induce higher virus dispersion.

    PubMed

    Lin, Fang-Jing; Bosquée, Emilie; Liu, Ying-Jie; Chen, Ju-Lian; Yong, Liu; Francis, Frédéric

    2016-09-01

    Aphids cause serious damages to crops not only by tacking sap but also by transmitting numerous viruses. To develop biological control, the aphid alarm pheromone, namely E-β-farnesene (EβF), has been demonstrated to be efficient to repel aphids and as attract beneficials, making it a potential tool to control aphid pests. Considering aphids also as virus vectors, changes of their behavior could also interfere with the virus acquisition and transmission process. Here, a combination of two aphid species and two potato virus models were selected to test the influence of EβF release on aphid and virus dispersion under laboratory conditions. EβF release was found to significantly decrease the population of Myzus persicae and Macrosiphum euphorbiae around the infochemical releaser but simultaneously also increasing the dispersal of Potato Virus Y (PVY). At the opposite, no significant difference for Potato Leaf Roll Virus (PLRV) transmission efficiency was observed with similar aphid alarm pheromone releases for none of the aphid species. These results provide some support to carefully consider infochemical releasers not only for push-pull strategy and pest control but also to include viral disease in a the plant protection to aphids as they are also efficient virus vectors. Impact of aphid kinds and transmission mechanisms will be discussed according to the large variation found between persistent and non persistent potato viruses and interactions with aphids and related infochemicals.

  7. Internal roll compression system

    DOEpatents

    Anderson, Graydon E.

    1985-01-01

    This invention is a machine for squeezing water out of peat or other material of low tensile strength; the machine including an inner roll eccentrically positioned inside a tubular outer roll, so as to form a gradually increasing pinch area at one point therebetween, so that, as the rolls rotate, the material is placed between the rolls, and gets wrung out when passing through the pinch area.

  8. Whitefly resistance traits derived from the wild tomato Solanum pimpinellifolium affect the preference and feeding behavior of Bemisia tabaci and reduce the spread of Tomato yellow leaf curl virus.

    PubMed

    Rodríguez-López, M J; Garzo, E; Bonani, J P; Fereres, A; Fernández-Muñoz, R; Moriones, E

    2011-10-01

    Breeding of tomato genotypes that limit whitefly (Bemisia tabaci) access and feeding might reduce the spread of Tomato yellow leaf curl virus (TYLCV), a begomovirus (genus Begomovirus, family Geminiviridae) that is the causal agent of tomato yellow leaf curl disease. TYLCV is restricted to the phloem and is transmitted in a persistent manner by B. tabaci. The tomato breeding line ABL 14-8 was developed by introgressing type IV leaf glandular trichomes and secretion of acylsucroses from the wild tomato Solanum pimpinellifolium accession TO-937 into the genetic background of the whitefly- and virus-susceptible tomato cultivar Moneymaker. Results of preference bioassays with ABL 14-8 versus Moneymaker indicated that presence of type IV glandular trichomes and the production of acylsucrose deterred the landing and settling of B. tabaci on ABL 14-8. Moreover, electrical penetration graph studies indicated that B. tabaci adults spent more time in nonprobing activities and showed a reduced ability to start probing. Such behavior resulted in a reduced ability to reach the phloem. The superficial type of resistance observed in ABL 14-8 against B. tabaci probing significantly reduced primary and secondary spread of TYLCV. PMID:21615206

  9. Eugenol confers resistance to Tomato yellow leaf curl virus (TYLCV) by regulating the expression of SlPer1 in tomato plants.

    PubMed

    Sun, Wei-Jie; Lv, Wen-Jing; Li, Li-Na; Yin, Gan; Hang, Xiaofang; Xue, Yanfeng; Chen, Jian; Shi, Zhiqi

    2016-05-25

    Tomato yellow leaf curl virus (TYLCV) is one of the most devastating plant diseases, and poses a significant agricultural concern because of the lack of an efficient control method. Eugenol is a plant-derived natural compound that has been widely used as a food additive and in medicine. In the present study, we demonstrated the potential of eugenol to enhance the resistance of tomato plants to TYLCV. The anti-TYLCV efficiency of eugenol was significantly higher than that of moroxydine hydrochloride (MH), a widely used commercial antiviral agent. Eugenol application stimulated the production of endogenous nitric oxide (NO) and salicylic acid (SA) in tomato plants. The full-length cDNA of SlPer1, which has been suggested to be a host R gene specific to TYLCV, was isolated from tomato plants. A sequence analysis suggested that SlPer1 might be a nucleobase-ascorbate transporter (NAT) belonging to the permease family. The transcript levels of SlPer1 increased markedly in response to treatment with eugenol or TYLCV inoculation. The results of this study also showed that SlPer1 expression was strongly induced by SA, MeJA (jasmonic acid methyl ester), and NO. Thus, we propose that the increased transcription of SlPer1 contributed to the high anti-TYLCV efficiency of eugenol, which might involve in the generation of endogenous SA and NO. Such findings provide the basis for the development of eugenol as an environmental-friendly agricultural antiviral agent. PMID:26776605

  10. Evaluation of Cotton Leaf Curl Virus Resistance in BC1, BC2, and BC3 Progenies from an Interspecific Cross between Gossypium arboreum and Gossypium hirsutum

    PubMed Central

    Nazeer, Wajad; Tipu, Abdul Latif; Ahmad, Saghir; Mahmood, Khalid; Mahmood, Abid; Zhou, Baoliang

    2014-01-01

    Cotton leaf curl virus disease (CLCuD) is an important constraint to cotton production. The resistance of G. arboreum to this devastating disease is well documented. In the present investigation, we explored the possibility of transferring genes for resistance to CLCuD from G. arboreum (2n = 26) cv 15-Mollisoni into G. hirsutum (2n = 52) cv CRSM-38 through conventional breeding. We investigated the cytology of the BC1 to BC3 progenies of direct and reciprocal crosses of G. arboreum and G. hirsutum and evaluated their resistance to CLCuD. The F1 progenies were completely resistant to this disease, while a decrease in resistance was observed in all backcross generations. As backcrossing progressed, the disease incidence increased in BC1 (1.7–2.0%), BC2 (1.8–4.0%), and BC3 (4.2–7.0%). However, the disease incidence was much lower than that of the check variety CIM-496, with a CLCuD incidence of 96%. Additionally, the disease incidence percentage was lower in the direct cross 2(G. arboreum)×G. hirsutum than in that of G. hirsutum×G. arboreum. Phenotypic resemblance of BC1 ∼BC3 progenies to G. arboreum confirmed the success of cross between the two species. Cytological studies of CLCuD-resistant plants revealed that the frequency of univalents and multivalents was high in BC1, with sterile or partially fertile plants, but low in BC2 (in both combinations), with shy bearing plants. In BC3, most of the plants exhibited normal bearing ability due to the high frequency of chromosome associations (bivalents). The assessment of CLCuD through grafting showed that the BC1 to BC3 progenies were highly resistant to this disease. Thus, this study successfully demonstrates the possibility of introgressing CLCuD resistance genes from G. arboreum to G. hirsutum. PMID:25372141

  11. Development of a salicylic acid inducible minimal sub-genomic transcript promoter from Figwort mosaic virus with enhanced root- and leaf-activity using TGACG motif rearrangement.

    PubMed

    Kumar, Deepak; Patro, Sunita; Ghosh, Jayasish; Das, Abhimanyu; Maiti, Indu B; Dey, Nrisingha

    2012-07-15

    In Figwort mosaic virus sub-genomic transcript promoter (F-Sgt), function of the TGACG-regulatory motif, was investigated in the background of artificially designed promoter sequences. The 131bp (FS, -100 to +31) long F-Sgt promoter sequence containing one TGACG motif [FS-(TGACG)] was engineered to generate a set of three modified promoter constructs: [FS-(TGACG)(2), containing one additional TGACG motif at 7 nucleotides upstream of the original one], [FS-(TGACG)(3), containing two additional TGACG motifs at 7 nucleotides upstream and two nucleotides downstream of the original one] and [FS-(TGCTG)(mu), having a mutated TGACG motif]. EMSA and foot-printing analysis confirmed binding of tobacco nuclear factors with modified TGACG motif/s. The transcription-activation of the GUS gene by the TGACG motif/s in above promoter constructs was examined in transgenic tobacco and Arabidopsis plants and observed that the transcription activation was affected by the spacing/s and number/s of the TGACG motif/s. The FS-(TGACG)(2) promoter showed strongest root-activity compared to other modified and CaMV35S promoters. Also under salicylic acid (SA) stress, the leaf-activity of the said promoter was further enhanced. All above findings were confirmed by real-time and semi-qRT PCR analysis. Taken together, these results clearly demonstrated that the TGACG motif plays an important role in inducing the root-specific expression of the F-Sgt promoter. This study advocates the importance of genetic manipulation of functional cis-motif for amending the tissue specificity of a plant promoter. SA inducible FS-(TGACG)(2) promoter with enhanced activity could be a useful candidate promoter for developing plants with enhanced crop productivity.

  12. Effect of herbivore damage on broad leaf motion in wind

    NASA Astrophysics Data System (ADS)

    Burnett, Nicholas; Kothari, Adit

    2015-11-01

    Terrestrial plants regularly experience wind that imposes aerodynamic forces on the plants' leaves. Passive leaf motion (e.g. fluttering) and reconfiguration (e.g. rolling into a cone shape) in wind can affect the drag on the leaf. In the study of passive leaf motion in wind, little attention has been given to the effect of herbivory. Herbivores may alter leaf motion in wind by making holes in the leaf. Also, a small herbivore (e.g. snail) on a leaf can act as a point mass, thereby affecting the leaf's motion in wind. Conversely, accelerations imposed on an herbivore sitting on a leaf by the moving leaf may serve as a defense by dislodging the herbivore. In the present study, we investigated how point masses (>1 g) and holes in leaves of the tuliptree affected passive leaf motion in turbulent winds of 1 and 5 m s-1. Leaf motion was unaffected by holes in the leaf surface (about 10% of leaf area), but an herbivore's mass significantly damped the accelerations of fluttering leaves. These results suggest that an herbivore's mass, but not the damage it inflicts, can affect leaf motion in the wind. Furthermore, the damping of leaf fluttering from an herbivore's mass may prevent passive leaf motions from being an effective herbivore defense.

  13. Compositional analysis of tubers from insect and virus resistant potato plants.

    PubMed

    Rogan, G J; Bookout, J T; Duncan, D R; Fuchs, R L; Lavrik, P B; Love, S L; Mueth, M; Olson, T; Owens, E D; Raymond, P J; Zalewski, J

    2000-12-01

    Genetically modified potato plants that are resistant to the Colorado potato beetle, plus either the potato leaf roll virus or potato virus Y, have recently been commercialized. As part of the safety assessment for plants produced by modern biotechnology, the composition of the food/feed must be compared to that of the food/feed produced by an equivalent plant variety from a conventional source. The composition of important nutritional and antinutritional factors in tubers produced by virus- and insect-resistant potato plants were compared to tubers produced by conventional potato plants. Key nutritional, quality, and antinutritional components measured were total solids, vitamin C, dextrose, sucrose, soluble protein, and glycoalkaloids. Proximate analyses included fat, ash, calories, total protein, and crude fiber. Minor nutrients measured were vitamin B6, niacin, copper, magnesium, potassium, and amino acids. The results from these analyses confirm that tubers produced by insect- and virus-protected varieties are substantially equivalent to tubers produced by conventional potato varieties.

  14. Leaf Activities.

    ERIC Educational Resources Information Center

    Mingie, Walter

    Leaf activities can provide a means of using basic concepts of outdoor education to learn in elementary level subject areas. Equipment needed includes leaves, a clipboard with paper, and a pencil. A bag of leaves may be brought into the classroom if weather conditions or time do not permit going outdoors. Each student should pick a leaf, examine…

  15. Making a friend from a foe: expressing a GroEL gene from the whitefly Bemisia tabaci in the phloem of tomato plants confers resistance to tomato yellow leaf curl virus.

    PubMed

    Akad, F; Eybishtz, A; Edelbaum, D; Gorovits, R; Dar-Issa, O; Iraki, N; Czosnek, H

    2007-01-01

    Some (perhaps all) plant viruses transmitted in a circulative manner by their insect vectors avoid destruction in the haemolymph by interacting with GroEL homologues, ensuring transmission. We have previously shown that the phloem-limited begomovirus tomato yellow leaf curl virus (TYLCV) interacts in vivo and in vitro with GroEL produced by the whitefly vector Bemisia tabaci. In this study, we have exploited this phenomenon to generate transgenic tomato plants expressing the whitefly GroEL in their phloem. We postulated that following inoculation, TYLCV particles will be trapped by GroEL in the plant phloem, thereby inhibiting virus replication and movement, thereby rendering the plants resistant. A whitefly GroEL gene was cloned in an Agrobacterium vector under the control of an Arabidopsis phloem-specific promoter, which was used to transform two tomato genotypes. During three consecutive generations, plants expressing GroEL exhibited mild or no disease symptoms upon whitefly-mediated inoculation of TYLCV. In vitro assays indicated that the sap of resistant plants contained GroEL-TYLCV complexes. Infected resistant plants served as virus source for whitefly-mediated transmission as effectively as infected non-transgenic tomato. Non-transgenic susceptible tomato plants grafted on resistant GroEL-transgenic scions remained susceptible, although GroEL translocated into the grafted plant and GroEL-TYLCV complexes were detected in the grafted tissues. PMID:17334947

  16. How to pattern a leaf.

    PubMed

    Bolduc, N; O'Connor, D; Moon, J; Lewis, M; Hake, S

    2012-01-01

    Leaf development presents a tremendous resource for tackling the question of patterning in biology. Leaves can be simple or highly dissected. They may have elaborated parts such as the tendrils of a pea leaf or the rolled blade of a carnivorous pitcher plant. Despite the variation in size, shape, and function, all leaves initiate in the same manner: from the flanks of a meristem. The maize leaf is useful for analysis of patterning due to the wealth of mutants and the distinct tissues along the proximal distal axis. The blade is distal, the sheath is proximal, and the ligule forms at the blade/sheath boundary. Establishment of this boundary involves the transcription factors LIGULELESS1 and LIGULELESS2 and the kinase LIGULELESS NARROW. The meristem-specific protein KNOTTED1 (KN1) binds and modulates the lg2 gene. Given the localization of KN1 at the proximal end of the leaf from the time of inception, we hypothesize that KN1 has a role in establishing the very proximal end of the leaf, whereas an auxin maximum guides the growing distal tip. PMID:23174765

  17. Understanding Rolle's Theorem

    ERIC Educational Resources Information Center

    Parameswaran, Revathy

    2009-01-01

    This paper reports on an experiment studying twelfth grade students' understanding of Rolle's Theorem. In particular, we study the influence of different concept images that students employ when solving reasoning tasks related to Rolle's Theorem. We argue that students' "container schema" and "motion schema" allow for rich concept images.…

  18. OsLBD3-7 Overexpression Induced Adaxially Rolled Leaves in Rice

    PubMed Central

    Zhang, Chunyu; Shao, Qinghao; Liu, Jun; Liu, Bin; Li, Hongyu

    2016-01-01

    Appropriate leaf rolling enhances erect-leaf habits and photosynthetic efficiency, which consequently improves grain yield. Here, we reported the novel lateral organ boundaries domain (LBD) gene OsLBD3-7, which is involved in the regulation of leaf rolling. OsLBD3-7 works as a transcription activator and its protein is located on the plasma membrane and in the nucleus. Overexpression of OsLBD3-7 leads to narrow and adaxially rolled leaves. Microscopy of flag leaf cross-sections indicated that overexpression of OsLBD3-7 led to a decrease in both bulliform cell size and number. Transcriptional analysis showed that key genes that had been reported to be negative regulators of bulliform cell development were up-regulated in transgenic plants. These results indicated that OsLBD3-7 might acts as an upstream regulatory gene of bulliform cell development to regulate leaf rolling, which will give more insights on the leaf rolling regulation mechanism. PMID:27258066

  19. Leaf Development

    PubMed Central

    2013-01-01

    Leaves are the most important organs for plants. Without leaves, plants cannot capture light energy or synthesize organic compounds via photosynthesis. Without leaves, plants would be unable perceive diverse environmental conditions, particularly those relating to light quality/quantity. Without leaves, plants would not be able to flower because all floral organs are modified leaves. Arabidopsis thaliana is a good model system for analyzing mechanisms of eudicotyledonous, simple-leaf development. The first section of this review provides a brief history of studies on development in Arabidopsis leaves. This history largely coincides with a general history of advancement in understanding of the genetic mechanisms operating during simple-leaf development in angiosperms. In the second section, I outline events in Arabidopsis leaf development, with emphasis on genetic controls. Current knowledge of six important components in these developmental events is summarized in detail, followed by concluding remarks and perspectives. PMID:23864837

  20. Scavenging of reactive oxygen species in apoplastic and symplastic areas of rolled leaves in Ctenanthe setosa under drought stress.

    PubMed

    Saruhan, Neslihan; Terzi, Rabiye; Sağlam, Aykut; Kadioğlu, Asim

    2010-09-01

    The correspondence among apoplastic and symplastic antioxidant status, stomatal conductance and water potential was investigated during leaf rolling in Ctenanthe setosa (Rosc.) Eichler (Marantaceae) under drought stress. Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate form). In the leaf symplast, the highest changes were found in catalase (CAT) and guaiacol peroxidase (GPX) activities when compared to score 1 during leaf rolling. No significant change was observed in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the symplast of leaf during the rolling. The same phenomenon was also present in the symplast of petiole except APX activity. In the leaf apoplast, the highest increase occurred in APX and GPX activities, whilst a slight increase in CAT and SOD activities. In the apoplast of petiole, the highest increment was found only in GPX activity, while there were small increases in SOD, APX and CAT activities. Hydrogen peroxide content increased up to score 3 in the apoplast and symplast of leaf and petiole but then slightly decreased. Also, superoxide production increased in the leaf and petiole apoplast but its quantity in the apoplast was much more than that of the symplast. On the other hand, NAD(P)H oxidase activity increased in the leaf but no change was observed in the petiole. In conclusion, as a result of water deficit during leaf rolling antioxidant enzymes are induced to scavenging of ROS produced in symplast and apoplast. PMID:20724275

  1. Scavenging of reactive oxygen species in apoplastic and symplastic areas of rolled leaves in Ctenanthe setosa under drought stress.

    PubMed

    Saruhan, Neslihan; Terzi, Rabiye; Sağlam, Aykut; Kadioğlu, Asim

    2010-09-01

    The correspondence among apoplastic and symplastic antioxidant status, stomatal conductance and water potential was investigated during leaf rolling in Ctenanthe setosa (Rosc.) Eichler (Marantaceae) under drought stress. Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate form). In the leaf symplast, the highest changes were found in catalase (CAT) and guaiacol peroxidase (GPX) activities when compared to score 1 during leaf rolling. No significant change was observed in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the symplast of leaf during the rolling. The same phenomenon was also present in the symplast of petiole except APX activity. In the leaf apoplast, the highest increase occurred in APX and GPX activities, whilst a slight increase in CAT and SOD activities. In the apoplast of petiole, the highest increment was found only in GPX activity, while there were small increases in SOD, APX and CAT activities. Hydrogen peroxide content increased up to score 3 in the apoplast and symplast of leaf and petiole but then slightly decreased. Also, superoxide production increased in the leaf and petiole apoplast but its quantity in the apoplast was much more than that of the symplast. On the other hand, NAD(P)H oxidase activity increased in the leaf but no change was observed in the petiole. In conclusion, as a result of water deficit during leaf rolling antioxidant enzymes are induced to scavenging of ROS produced in symplast and apoplast.

  2. A new virus discovered by immunocapture of double-stranded RNA, a rapid method for virus enrichment in metagenomic studies.

    PubMed

    Blouin, Arnaud G; Ross, Howard A; Hobson-Peters, Jody; O'Brien, Caitlin A; Warren, Ben; MacDiarmid, Robin

    2016-09-01

    Next-generation sequencing technologies enable the rapid identification of viral infection of diseased organisms. However, despite a consistent decrease in sequencing costs, it is difficult to justify their use in large-scale surveys without a virus sequence enrichment technique. As the majority of plant viruses have an RNA genome, a common approach is to extract the double-stranded RNA (dsRNA) replicative form, to enrich the replicating virus genetic material over the host background. The traditional dsRNA extraction is time-consuming and labour-intensive. We present an alternative method to enrich dsRNA from plant extracts using anti-dsRNA monoclonal antibodies in a pull-down assay. The extracted dsRNA can be amplified by reverse transcriptase-polymerase chain reaction and sequenced by next-generation sequencing. In our study, we have selected three distinct plant hosts: Māori potato (Solanum tuberosum), rengarenga (Arthropodium cirratum) and broadleaved dock (Rumex obtusifolius) representing a cultivated crop, a New Zealand-native ornamental plant and a weed, respectively. Of the sequence data obtained, 31-74% of the reads were of viral origin, and we identified five viruses including Potato virus Y and Potato virus S in potato; Turnip mosaic virus in rengarenga (a new host record); and in the dock sample Cherry leaf roll virus and a novel virus belonging to the genus Macluravirus. We believe that this new assay represents a significant opportunity to upscale virus ecology studies from environmental, primary industry and/or medical samples. PMID:26990372

  3. A new virus discovered by immunocapture of double-stranded RNA, a rapid method for virus enrichment in metagenomic studies.

    PubMed

    Blouin, Arnaud G; Ross, Howard A; Hobson-Peters, Jody; O'Brien, Caitlin A; Warren, Ben; MacDiarmid, Robin

    2016-09-01

    Next-generation sequencing technologies enable the rapid identification of viral infection of diseased organisms. However, despite a consistent decrease in sequencing costs, it is difficult to justify their use in large-scale surveys without a virus sequence enrichment technique. As the majority of plant viruses have an RNA genome, a common approach is to extract the double-stranded RNA (dsRNA) replicative form, to enrich the replicating virus genetic material over the host background. The traditional dsRNA extraction is time-consuming and labour-intensive. We present an alternative method to enrich dsRNA from plant extracts using anti-dsRNA monoclonal antibodies in a pull-down assay. The extracted dsRNA can be amplified by reverse transcriptase-polymerase chain reaction and sequenced by next-generation sequencing. In our study, we have selected three distinct plant hosts: Māori potato (Solanum tuberosum), rengarenga (Arthropodium cirratum) and broadleaved dock (Rumex obtusifolius) representing a cultivated crop, a New Zealand-native ornamental plant and a weed, respectively. Of the sequence data obtained, 31-74% of the reads were of viral origin, and we identified five viruses including Potato virus Y and Potato virus S in potato; Turnip mosaic virus in rengarenga (a new host record); and in the dock sample Cherry leaf roll virus and a novel virus belonging to the genus Macluravirus. We believe that this new assay represents a significant opportunity to upscale virus ecology studies from environmental, primary industry and/or medical samples.

  4. Mapping Quantitative Trait Loci of Resistance to Tomato Spotted Wilt Virus and Leaf Spots in a Recombinant Inbred Line Population of Peanut (Arachis hypogaea L.) from SunOleic 97R and NC94022

    PubMed Central

    Feng, Suping; Qiao, Lixian; Culbreath, Albert K.; Kale, Sandip; Wang, Jianping; Holbrook, C. Corley; Zhuang, Weijian; Varshney, Rajeev K.; Guo, Baozhu

    2016-01-01

    Peanut is vulnerable to a range of diseases, such as Tomato spotted wilt virus (TSWV) and leaf spots which will cause significant yield loss. The most sustainable, economical and eco-friendly solution for managing peanut diseases is development of improved cultivars with high level of resistance. We developed a recombinant inbred line population from the cross between SunOleic 97R and NC94022, named as the S-population. An improved genetic linkage map was developed for the S-population with 248 marker loci and a marker density of 5.7 cM/loci. This genetic map was also compared with the physical map of diploid progenitors of tetraploid peanut, resulting in an overall co-linearity of about 60% with the average co-linearity of 68% for the A sub-genome and 47% for the B sub-genome. The analysis using the improved genetic map and multi-season (2010–2013) phenotypic data resulted in the identification of 48 quantitative trait loci (QTLs) with phenotypic variance explained (PVE) from 3.88 to 29.14%. Of the 48 QTLs, six QTLs were identified for resistance to TSWV, 22 QTLs for early leaf spot (ELS) and 20 QTLs for late leaf spot (LLS), which included four, six, and six major QTLs (PVE larger than 10%) for each disease, respectively. A total of six major genomic regions (MGR) were found to have QTLs controlling more than one disease resistance. The identified QTLs and resistance gene-rich MGRs will facilitate further discovery of resistance genes and development of molecular markers for these important diseases. PMID:27427980

  5. Mapping Quantitative Trait Loci of Resistance to Tomato Spotted Wilt Virus and Leaf Spots in a Recombinant Inbred Line Population of Peanut (Arachis hypogaea L.) from SunOleic 97R and NC94022.

    PubMed

    Khera, Pawan; Pandey, Manish K; Wang, Hui; Feng, Suping; Qiao, Lixian; Culbreath, Albert K; Kale, Sandip; Wang, Jianping; Holbrook, C Corley; Zhuang, Weijian; Varshney, Rajeev K; Guo, Baozhu

    2016-01-01

    Peanut is vulnerable to a range of diseases, such as Tomato spotted wilt virus (TSWV) and leaf spots which will cause significant yield loss. The most sustainable, economical and eco-friendly solution for managing peanut diseases is development of improved cultivars with high level of resistance. We developed a recombinant inbred line population from the cross between SunOleic 97R and NC94022, named as the S-population. An improved genetic linkage map was developed for the S-population with 248 marker loci and a marker density of 5.7 cM/loci. This genetic map was also compared with the physical map of diploid progenitors of tetraploid peanut, resulting in an overall co-linearity of about 60% with the average co-linearity of 68% for the A sub-genome and 47% for the B sub-genome. The analysis using the improved genetic map and multi-season (2010-2013) phenotypic data resulted in the identification of 48 quantitative trait loci (QTLs) with phenotypic variance explained (PVE) from 3.88 to 29.14%. Of the 48 QTLs, six QTLs were identified for resistance to TSWV, 22 QTLs for early leaf spot (ELS) and 20 QTLs for late leaf spot (LLS), which included four, six, and six major QTLs (PVE larger than 10%) for each disease, respectively. A total of six major genomic regions (MGR) were found to have QTLs controlling more than one disease resistance. The identified QTLs and resistance gene-rich MGRs will facilitate further discovery of resistance genes and development of molecular markers for these important diseases. PMID:27427980

  6. The C2 protein of tomato yellow leaf curl Sardinia virus acts as a pathogenicity determinant and a 16-amino acid domain is responsible for inducing a hypersensitive response in plants.

    PubMed

    Matić, Slavica; Pegoraro, Mattia; Noris, Emanuela

    2016-04-01

    The role of the C2 protein in the pathogenicity of tomato yellow leaf curl Sardinia virus (TYLCSV) was investigated. Here we report that Agrobacterium-mediated transient expression of TYLCSV C2 resulted in a strong hypersensitive response (HR) in Nicotiana benthamiana, N. tabacum, and Arabidopsis thaliana, with induction of plant cell death and production of H2O2. Since HR is not evident in plants infected by TYLCSV, it is expected that TYLCSV encodes a gene (or genes) that counters this response. HR was partially counteracted by co-agroinfiltration of TYLCSV V2 and Rep, leading to chlorotic reaction, with no HR development. Considering that the corresponding C2 protein of the closely related tomato yellow leaf curl virus (TYLCV) did not induce HR, alignment of the C2 proteins of TYLCSV and TYLCV were carried out and a hypervariable region of 16 amino acids was identified. Its role in the induction of HR was demonstrated using TYLCSV-TYLCV C2 chimeric genes, encoding two TYLCSV C2 variants with a complete (16 aa) or a partial (10 aa only) swap of the corresponding sequence of TYLCV C2. Furthermore, using NahG transgenic N. benthamiana lines compromised in the accumulation of salicylic acid (SA), a key regulator of HR, only a chlorotic response occurred in TYLCSV C2-infiltrated tissue, indicating that SA participates in such plant defense process. These findings demonstrate that TYLCSV C2 acts as a pathogenicity determinant and induces host defense responses controlled by the SA pathway. PMID:26826600

  7. Spray Rolling Aluminum Strip

    SciTech Connect

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

    2006-05-10

    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  8. Wear of hot rolling mill rolls: An overview

    NASA Astrophysics Data System (ADS)

    Spuzic, S.; Strafford, K. N.; Subramanian, C.; Savage, G.

    1994-08-01

    Rolling is today one of the most important industrial processes because a greater volume of material is worked by rolling than by any other technique. Roll wear is a multiplex process where mechanical and thermal fatigue combines with impact, abrasion, adhesion and corrosion, which all depend on system interactions rather than material characteristics only. The situation is more complicated in section rolling because of the intricacy of roll geometry. Wear variables and modes are reviewed along with published methods and models used in the study and testing of roll wear. This paper reviews key aspects of roll wear control - roll material properties, roll pass design, and system factors such as temperature, loads and sliding velocity. An overview of roll materials is given including adamites, high Cr materials, high speed tool steels and compound rolls. Non-uniform wear, recognized as the most detrimental phenomenon in section rolling, can be controlled by roll pass design. This can be achieved by computer-aided graphical and statistical analyses of various pass series. Preliminary results obtained from pilot tests conducted using a two-disc hot wear rig and a scratch tester are discussed.

  9. Extended slow-roll conditions and rapid-roll conditions

    SciTech Connect

    Chiba, Takeshi; Yamaguchi, Masahide E-mail: gucci@phys.aoyama.ac.jp

    2008-10-15

    We derive slow-roll conditions for a scalar field which is non-minimally coupled with gravity in a consistent manner and express spectral indices of scalar/tensor perturbations in terms of the slow-roll parameters. The conformal invariance of the curvature perturbation is proved without linear approximations. Rapid-roll conditions are also derived, and the relation with the slow-roll conditions is discussed.

  10. METHOD OF ROLLING URANIUM

    DOEpatents

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  11. The 35-amino acid C2 protein of Cotton leaf curl Kokhran virus, Burewala, implicated in resistance breaking in cotton, retains some activities of the full-length protein.

    PubMed

    Akbar, Fazal; Iqbal, Zafar; Briddon, Rob W; Vazquez, Franck; Saeed, Muhammad

    2016-10-01

    With one exception, all the begomoviruses characterized so far encode an ~134-amino acid (aa) (A)C2 protein. The exception is the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bu), associated with resistance breaking in cotton across Pakistan and northwestern India, that encodes a truncated 35-aa C2. The C2 protein encoded by begomoviruses performs multiple functions including suppression of post-transcriptional gene silencing (PTGS), modulating microRNA (miRNA) expression and may be a pathogenicity determinant. The study described here was designed to investigate whether the CLCuKoV-Bu 35-aa C2 retains the activities of the full-length C2 protein. The results showed the 35-aa C2 of CLCuKoV-Bu acts as a pathogenicity determinant, suppresses PTGS and upregulates miRNA expression when expressed from a Potato virus X vector in Nicotiana benthamiana. The symptoms induced by expression of full-length C2 were more severe than those induced by the 35-aa C2. The accumulation of most developmental miRNAs decreases with the full-length C2 protein and increases with the 35-aa peptide of CLCuKoV-Bu. The study also revealed that 35-aa peptide of CLCuKoV-Bu maintains suppressor of silencing activity at a level equal to that of full-length C2. The significance of the results with respect to virus fitness and resistance breaking is discussed.

  12. Research on work roll thermal crown in cold rolling mill

    NASA Astrophysics Data System (ADS)

    Song, Lei; Shen, Mingang; Chen, Xuebo; Wang, Junsheng

    2013-05-01

    The factors which have influence on the work roll thermal crown in cold strip rolling are discussed. The heat transferring in three directions (radial axis and circumference) were considered for calculating the work roll thermal deformation. Therefore, it is a three dimensions unstable system for the work roll temperature calculation. The plastic deformation work and friction heat are calculated by the divided element and digital integration method. The simplified calculation model is built for the heat transferring along work roll. There are four zones for work roll heat transferring: roll gap zone air cooling zone emulsion zone rolls contact zone. The heat transferring between the zones is decided by the temperature difference. The inter temperature field and thermal deformation of work roll can be calculated by two-dimension finite difference method. The work roll temperature and thermal crown of actual application cold rolling mill are analyzed by the model. By the comparison between calculated values and measured values, the work roll thermal calculation model can meet the accuracy requirement of on-line control.

  13. The Tomato yellow leaf curl virus (TYLCV) V2 protein inhibits enzymatic activity of the host papain-like cysteine protease CYP1.

    PubMed

    Bar-Ziv, Amalia; Levy, Yael; Citovsky, Vitaly; Gafni, Yedidya

    2015-05-01

    The viral V2 protein is one of the key factors that Tomato yellow leaf curl geminivirus (TYLCV), a major tomato pathogen worldwide, utilizes to combat the host defense. Besides suppressing the plant RNA silencing defense by targeting the host SGS3 component of the silencing machinery, V2 also interacts with the host CYP1 protein, a papain-like cysteine protease likely involved in hypersensitive response reactions. The biological effects of the V2-CYP1 interaction, however, remain unknown. We addressed this question by demonstrating that V2 inhibits the enzymatic activity of CYP1, but does not interfere with post-translational maturation of this protein. PMID:25797621

  14. The Tomato yellow leaf curl virus (TYLCV) V2 protein inhibits enzymatic activity of the host papain-like cysteine protease CYP1

    PubMed Central

    Bar-Ziv, Amalia; Levy, Yael; Citovsky, Vitaly; Gafni, Yedidya

    2015-01-01

    The viral V2 protein is one of the key factors that Tomato yellow leaf curl geminivirus (TYLCV), a major tomato pathogen worldwide, utilizes to combat the host defense. Besides suppressing the plant RNA silencing defense by targeting the host SGS3 component of the silencing machinery, V2 also interacts with the host CYP1 protein, a papain-like cysteine protease likely involved in hypersensitive response reactions. The biological effects of the V2-CYP1 interaction, however, remain unknown. We addressed this question by demonstrating that V2 inhibits the enzymatic activity of CYP1, but does not interfere with post-translational maturation of this protein. PMID:25797621

  15. The Tomato yellow leaf curl virus (TYLCV) V2 protein inhibits enzymatic activity of the host papain-like cysteine protease CYP1.

    PubMed

    Bar-Ziv, Amalia; Levy, Yael; Citovsky, Vitaly; Gafni, Yedidya

    2015-05-01

    The viral V2 protein is one of the key factors that Tomato yellow leaf curl geminivirus (TYLCV), a major tomato pathogen worldwide, utilizes to combat the host defense. Besides suppressing the plant RNA silencing defense by targeting the host SGS3 component of the silencing machinery, V2 also interacts with the host CYP1 protein, a papain-like cysteine protease likely involved in hypersensitive response reactions. The biological effects of the V2-CYP1 interaction, however, remain unknown. We addressed this question by demonstrating that V2 inhibits the enzymatic activity of CYP1, but does not interfere with post-translational maturation of this protein.

  16. Cedar leaf oil poisoning

    MedlinePlus

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  17. Molecular characterisation of a novel cassava associated circular ssDNA virus.

    PubMed

    Dayaram, Anisha; Opong, Allen; Jäschke, Anja; Hadfield, James; Baschiera, Marianna; Dobson, Renwick C J; Offei, Samuel K; Shepherd, Dionne N; Martin, Darren P; Varsani, Arvind

    2012-06-01

    The application of sequence non-specific rolling circle amplification of circular single stranded (ss) DNA molecules to viral metagenomics has facilitated the discovery in various ecosystems of what is probably a diverse array of novel ssDNA viruses. Here we describe a putative novel ssDNA virus (at a genome level), cassava associated circular DNA virus (CasCV), isolated from cassava leaf samples infected with the fungi Collectotrichum and Plectosphaerella. CasCV has a circular ambisense genome and shares significant genome similarities with Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), Mosquito VEM virus SDBVL and Meles meles faecal virus (MmFV). The CasCV genome (2220 nt) has three large open reading frames. While it is probable that one of these encodes a capsid protein, the other two probably express a replication associated protein (Rep) following the removal of an intron such as that found in the Rep encoding genes of some geminiviruses. This Rep would contain four conserved rolling circle replication (RCR) related motifs that have previously been identified in geminivirus, circovirus and nanovirus Reps. Given both that the CasCV Rep and CP share 62.7% and 39.8% amino acid identity respectively with the Rep and CP of SsHADV-1, and that CasCV was discovered associated with cassava infecting fungi, we suggest that CasCV should be classified within the mycovirus taxonomic family. However, host range studies using infectious clones will be required to demonstrate the novel virus' likely origin and actual host species.

  18. The C2 Protein from the Geminivirus Tomato Yellow Leaf Curl Sardinia Virus Decreases Sensitivity to Jasmonates and Suppresses Jasmonate-Mediated Defences

    PubMed Central

    Rosas-Díaz, Tábata; Macho, Alberto P.; Beuzón, Carmen R.; Lozano-Durán, Rosa; Bejarano, Eduardo R.

    2016-01-01

    An increasing body of evidence points at a role of the plant hormones jasmonates (JAs) in determining the outcome of plant-virus interactions. Geminiviruses, small DNA viruses infecting a wide range of plant species worldwide, encode a multifunctional protein, C2, which is essential for full pathogenicity. The C2 protein has been shown to suppress the JA response, although the current view on the extent of this effect and the underlying molecular mechanisms is incomplete. In this work, we use a combination of exogenous hormone treatments, microarray analysis, and pathogen infections to analyze, in detail, the suppression of the JA response exerted by C2. Our results indicate that C2 specifically affects certain JA-induced responses, namely defence and secondary metabolism, and show that plants expressing C2 are more susceptible to pathogen attack. We propose a model in which C2 might interfere with the JA response at several levels. PMID:27135228

  19. Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

    PubMed Central

    Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209

  20. Explicit nonlinear finite element geometric analysis of parabolic leaf springs under various loads.

    PubMed

    Kong, Y S; Omar, M Z; Chua, L B; Abdullah, S

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

  1. Roll Eccentricity Control Using Identified Eccentricity of Top/Bottom Rolls by Roll Force

    NASA Astrophysics Data System (ADS)

    Imanari, Hiroyuki; Koshinuma, Kazuyoshi

    Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills, and it affects product thickness accuracy. It cannot be measured directly by sensors, so it should be identified by measured thickness or measured roll force. When there is a large difference of diameters between top and bottom back up roll, the performance of roll eccentricity control using feedback signals of roll force or thickness has not been so good. Also it has been difficult for the control to be applied from the most head end because it is necessary to identify the roll eccentricity during rolling. A new roll eccentricity control has been developed to improve these disadvantages and to get better performance. The method identifies top and bottom roll eccentricity respectively from one signal of roll force and it can start the control from head end. In this paper the new control method is introduced and actual application results to a hot strip mill are shown.

  2. The induction of stromule formation by a plant DNA-virus in epidermal leaf tissues suggests a novel intra- and intercellular macromolecular trafficking route

    PubMed Central

    Krenz, Björn; Jeske, Holger; Kleinow, Tatjana

    2012-01-01

    Stromules are dynamic thin protrusions of membrane envelope from plant cell plastids. Despite considerable progress in understanding the importance of certain cytoskeleton elements and motor proteins for stromule maintenance, their function within the cell has yet to be unraveled. Several viruses cause a remodulation of plastid structures and stromule biogenesis within their host plants. For RNA-viruses these interactions were demonstrated to be relevant to the infection process. An involvement of plastids and stromules is assumed in the DNA-virus life cycle as well, but their functional role needs to be determined. Recent findings support a participation of heat shock cognate 70 kDa protein (cpHSC70-1)-containing stromules induced by a DNA-virus infection (Abutilon mosaic virus, AbMV, Geminiviridae) in intra- and intercellular molecule exchange. The chaperone cpHSC70-1 was shown to interact with the AbMV movement protein (MP). Bimolecular fluorescence complementation confirmed the interaction of cpHSC70-1 and MP, and showed a homo-oligomerization of either protein in planta. The complexes were detected at the cellular margin and co-localized with plastids. In healthy plant tissues cpHSC70-1-oligomers occurred in distinct spots at chloroplasts and in small filaments extending from plastids to the cell periphery. AbMV-infection induced a cpHSC70-1-containing stromule network that exhibits elliptical dilations and transverses whole cells. Silencing of the cpHSC70 gene revealed an impact of cpHSC70 on chloroplast stability and restricted AbMV movement, but not viral DNA accumulation. Based on these data, a model is suggested in which these stromules function in molecule exchange between plastids and other organelles and perhaps other cells. AbMV may utilize cpHSC70-1 for trafficking along plastids and stromules into a neighboring cell or from plastids into the nucleus. Experimental approaches to investigate this hypothesis are discussed. PMID:23293643

  3. GRCop-84 Rolling Parameter Study

    NASA Technical Reports Server (NTRS)

    Loewenthal, William S.; Ellis, David L.

    2008-01-01

    This report is a section of the final report on the GRCop-84 task of the Constellation Program and incorporates the results obtained between October 2000 and September 2005, when the program ended. NASA Glenn Research Center (GRC) has developed a new copper alloy, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb), for rocket engine main combustion chamber components that will improve rocket engine life and performance. This work examines the sensitivity of GRCop-84 mechanical properties to rolling parameters as a means to better define rolling parameters for commercial warm rolling. Experiment variables studied were total reduction, rolling temperature, rolling speed, and post rolling annealing heat treatment. The responses were tensile properties measured at 23 and 500 C, hardness, and creep at three stress-temperature combinations. Understanding these relationships will better define boundaries for a robust commercial warm rolling process. The four processing parameters were varied within limits consistent with typical commercial production processes. Testing revealed that the rolling-related variables selected have a minimal influence on tensile, hardness, and creep properties over the range of values tested. Annealing had the expected result of lowering room temperature hardness and strength while increasing room temperature elongations with 600 C (1112 F) having the most effect. These results indicate that the process conditions to warm roll plate and sheet for these variables can range over wide levels without negatively impacting mechanical properties. Incorporating broader process ranges in future rolling campaigns should lower commercial rolling costs through increased productivity.

  4. Ecosystem engineers on plants: indirect facilitation of arthropod communities by leaf-rollers at different scales.

    PubMed

    Vieira, Camila; Romero, Gustavo Q

    2013-07-01

    Ecosystem engineering is a process by which organisms change the distribution of resources and create new habitats for other species via non-trophic interactions. Leaf-rolling caterpillars can act as ecosystem engineers because they provide shelter to secondary users. In this study, we report the influence of leaf-rolling caterpillars on speciose tropical arthropod communities along both spatial scales (leaf-level and plant-level effects) and temporal scales (dry and rainy seasons). We predict that rolled leaves can amplify arthropod diversity at both the leaf and plant levels and that this effect is stronger in dry seasons, when arthropods are prone to desiccation. Our results show that the abundance, richness, and biomass of arthropods within several guilds increased up to 22-fold in naturally and artificially created leaf shelters relative to unaltered leaves. These effects were observed at similar magnitudes at both the leaf and plant scales. Variation in the shelter architecture (funnel, cylinders) did not influence arthropod parameters, as diversity, abundance, orbiomass, but rolled leaves had distinct species composition if compared with unaltered leaves. As expected, these arthropod parameters on the plants with rolled leaves were on average approximately twofold higher in the dry season. Empty leaf rolls and whole plants were rapidly recolonized by arthropods over time, implying a fast replacement of individuals; within 15-day intervals the rolls and plants reached a species saturation. This study is the first to examine the extended effects of engineering caterpillars as diversity amplifiers at different temporal and spatial scales. Because shelter-building caterpillars are ubiquitous organisms in tropical and temperate forests, they can be considered key structuring elements for arthropod communities on plants.

  5. Analysis of sequences from field samples reveals the presence of the recently described pepper vein yellows virus (genus Polerovirus) in six additional countries.

    PubMed

    Knierim, Dennis; Tsai, Wen-Shi; Kenyon, Lawrence

    2013-06-01

    Polerovirus infection was detected by reverse transcription polymerase chain reaction (RT-PCR) in 29 pepper plants (Capsicum spp.) and one black nightshade plant (Solanum nigrum) sample collected from fields in India, Indonesia, Mali, Philippines, Thailand and Taiwan. At least two representative samples for each country were selected to generate a general polerovirus RT-PCR product of 1.4 kb length for sequencing. Sequence analysis of the partial genome sequences revealed the presence of pepper vein yellows virus (PeVYV) in all 13 samples. A 1990 Australian herbarium sample of pepper described by serological means as infected with capsicum yellows virus (CYV) was identified by sequence analysis of a partial CP sequence as probably infected with a potato leaf roll virus (PLRV) isolate.

  6. Ocimum sanctum leaf extract induces drought stress tolerance in rice.

    PubMed

    Pandey, Veena; Ansari, M W; Tula, Suresh; Sahoo, R K; Bains, Gurdeep; Kumar, J; Tuteja, Narendra; Shukla, Alok

    2016-05-01

    Ocimum leaves are highly enriched in antioxidant components. Thus, its leaf extract, if applied in plants, is believed to efficiently scavenge ROS, thereby preventing oxidative damage under drought stress. Thus, the present study was performed in kharif 2013 and rabi 2014 season to evaluate the effect of aqueous leaf extract of Ocimum sanctum against drought stress in 2 rice genotype under glass house conditions. Here we show that various morpho- physiological (chlorophyll fluorescence, leaf rolling score, leaf tip burn, number of senesced leaves and total dry matter) and biochemical parameters (proline, malondialdehyde and superoxide dismutase content) were amended by Ocimum treatment in both the seasons. Application of Ocimum extract increased expression of dehydrin genes, while reducing expression of aquaporin genes in drought stressed rice plant. Thus, application of Ocimum leaf extract under drought stress can be suggested as a promising strategy to mitigate drought stress in economical, accessible and ecofriendly manner. PMID:26890603

  7. Walk and roll robot

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

  8. Molecular diagnosis of Papaya meleira virus (PMeV) from leaf samples of Carica papaya L. using conventional and real-time RT-PCR.

    PubMed

    Abreu, Paolla M V; Piccin, João G; Rodrigues, Silas P; Buss, David S; Ventura, José A; Fernandes, Patricia M B

    2012-03-01

    Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease. This study describes two methods for molecular diagnosis of PMeV using conventional and real-time PCR. These methods were shown to be more efficient than current methods of viral detection using extraction of PMeV dsRNA and observation of symptoms in the field. The methods described here were used to evaluate the effect of inoculation of papaya plants with purified PMeV dsRNA on the progress of PMeV infection. A single inoculation with PMeV dsRNA was observed to delay the progress of the virus infection by several weeks. The possibility of vertical transmission of PMeV was also investigated. No evidence was found for PMeV transmission through seeds collected from diseased fruit. The implications of these results for the epidemiology of PMeV and the management of papaya sticky disease are discussed.

  9. Continuous roll-to-roll amorphous silicon photovoltaic manufacturing technology

    NASA Astrophysics Data System (ADS)

    Izu, M.; Ovshinsky, S. R.; Deng, X.; Krisko, A.; Ovshinsky, H. C.; Narasimhan, K. L.; Young, R.

    1994-06-01

    Energy Conversion Devices, Inc. (ECD) has designed and constructed a 2 Megawatt (mW) manufacturing line that produces triple-junction spectrum-splitting a-Si alloy solar cells in a continuous roll-to-roll process. This manufacturing line has reliably and consistently produced high efficiency solar cells. We have demonstrated the production of 4ft 2 triple-junction two band-gap a-Si alloy PV production modules with 8% stable aperture area efficiency. The production line has successfully incorporated: 1) a band-gap profiled a-Si-Ge narrow band-gap solar cell deposited in a continuous roll-to-roll process using a proprietary gas distribution manifold and cathode configuration; and 2) a textured Ag/ZnO back-reflector deposited in a continuous roll-to-roll sputtering machine with production subcell yields greater than 99%.

  10. Roll-to-Roll production of carbon nanotubes based supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao

    2014-03-01

    Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 μm), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.

  11. A review of the mechanisms and components that determine the transmission efficiency of Tomato yellow leaf curl virus (Geminiviridae; Begomovirus) by its whitefly vector.

    PubMed

    Ghanim, Murad

    2014-06-24

    Begomoviruses are a group of icosahedral single stranded DNA viruses exclusively transmitted by the sweet potato whitefly Bemisia tabaci in a persistent, circulative manner. In this mode of transmission, begomoviruses are acquired by their insect vector as intact virions from the plant phloem, move along the food canal, foregut and esophagus and reach the midgut where they are absorbed into the hemolymph via the filter chamber. The filter chamber is the site where most of the ingested food is filtered, and the first site where the majority of begomoviruses appear to be translocated into the hemolymph via unknown proteins or receptors. Transport from the filter chamber to the hemolymph is aided by a Heat Shock Protein 70. Virus particles not translocated across the filter chamber circulate in the midgut loop but it is not known whether absorption into the hemolymph occurs along this loop. Localization studies have confirmed that begomoviruses are not associated with the hindgut and absorption of virions in this organ is unlikely. In the hemolymph, virions have been shown to interact with a GroEL chaperone produced by the whitefly's endosymbiontic bacteria for ensuring their safe journey to the salivary glands. Virions penetrate the primary salivary glands via unknown proteins or receptors and are transported and secreted outside the whitefly to the plant with salivary secretions. Several recent studies have demonstrated the implications of insect and endosymbiont proteins such as the heat shock protein 70 and the bacterial GroEL protein, in the transmission of begomoviruses by B. tabaci. Additional studies attempting to identify other proteins that aid or interact with begomoviruses along their circulation pathway in the whitefly are reviewed in this paper. PMID:24508344

  12. Genetic variability of Cotton leaf curl betasatellite in Northern India.

    PubMed

    Sohrab, Sayed Sartaj; Azhar, Esam I; Kamal, Mohammad A; Bhattacharya, P S; Rana, D

    2014-12-01

    Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA β were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2-55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana. PMID:25473373

  13. Rolling cuff flexible bellows

    DOEpatents

    Lambert, Donald R.

    1985-01-01

    A flexible connector apparatus used to join two stiff non-deformable members, such as piping. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

  14. VIEW OF HANDOPERATED ROLLING MILLS ROLLING STANDS FROM LEFT TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HAND-OPERATED ROLLING MILLS ROLLING STANDS FROM LEFT TO RIGHT: THREE HIGH; THREE HIGH; THREE HIGH; THREE HIGH (OPERATED AS A TWO-HIGH); TWO HIGH TWO HIGH MANUFACTURED BY BLAW-KNOX THREE HIGH MANUFACTURED BY LEWIS FOUNDRY AND MACHINE CO. - Cambria Iron Company, Gautier Works, 12" Mill, Clinton Street & Little Conemaugh River, Johnstown, Cambria County, PA

  15. Localization of Transmissible and Nontransmissible Viruses in the Vector Nematode Xiphinema americanum.

    PubMed

    Wang, Shouhua; Gergerich, Rose C; Wickizer, Sandra L; Kim, Kyung S

    2002-06-01

    ABSTRACT The inner lining of the food canal of nematodes that transmit plantinfecting viruses is regarded as the retention region of viruses. To characterize the location of transmissible and nontransmissible viruses in the vector nematode Xiphinema americanum, three nepoviruses, Tobacco ringspot virus (TRSV), Tomato ringspot virus(TomRSV), and Cherry leaf roll virus(CLRV), and one non-nematode-transmissible virus, Squash mosaic virus (SqMV), were evaluated for transmission efficiency and localization sites in the nematode. Transmission trials showed highest transmission efficiency for TomRSV (38% with 1 and 100% with 10 nematodes, respectively), intermediate efficiency for TRSV (27% with 1 and 65% with 10 nematodes, respectively), and no transmission for CLRV and SqMV. Electron microscopy and immunofluorescent labeling revealed that TRSV was primarily localized to the lining of the lumen of the stylet extension and the anterior esophagus, but only rarely in the triradiate lumen. Within a nematode population, particles of TRSV were no longer observed in these three regions 10 weeks after acquisition, and it is assumed that there was gradual and random loss of the virus from these areas. The percentage of nematodes that were labeled by virus-specific immunofluorescent labeling in a population of viruliferous nematodes decreased gradually after TRSV acquisition when the nematodes were placed on a nonhost of the virus, and the loss of immunofluorescent labeling paralleled the decrease in the ability of the nematode population to transmit the virus. TomRSV was localized only in the triradiate lumen based on thin-section electron microscopy. No virus-like particles were observed in any part of the food canal of nematodes that had fed on CLRV-infected plants. Virus-like particles that appeared to be partially degraded were observed only in the triradiate lumen of nematodes that had fed on SqMV-infected plants. These results clarified the status of localization of two

  16. Video Analysis of Rolling Cylinders

    ERIC Educational Resources Information Center

    Phommarach, S.; Wattanakasiwich, P.; Johnston, I.

    2012-01-01

    In this work, we studied the rolling motion of solid and hollow cylinders down an inclined plane at different angles. The motions were captured on video at 300 frames s[superscript -1], and the videos were analyzed frame by frame using video analysis software. Data from the real motion were compared with the theory of rolling down an inclined…

  17. LEDs are on a roll

    NASA Astrophysics Data System (ADS)

    Blom, Paul; van Mol, Ton

    2011-11-01

    Light-emitting diodes are more efficient than conventional lighting, but high production costs limit their uptake. Organic versions that can be produced using a cheap newspaper-style "roll-to-roll" printing process are likely to revolutionize our lighting and signage.

  18. First report of Persimmon cryptic virus and Persimmon virus A in Korea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2014, a total of 77 persimmon (Diospyros kaki Thunb.) trees from Korean commercial persimmon orchards were surveyed for Persimmon cryptic virus (PeCV) and Persimmon virus A (PeVA). Leaf samples were collected from symptomatic trees with necrosis (two), or mosaic and leaf malformations (one) and 7...

  19. Begomovirus diversity in tomato crops and weeds in Ecuador and the detection of a recombinant isolate of rhynchosia golden mosaic Yucatan virus infecting tomato.

    PubMed

    Paz-Carrasco, Lenin C; Castillo-Urquiza, Gloria P; Lima, Alison T M; Xavier, Cesar A D; Vivas-Vivas, Leticia M; Mizubuti, Eduardo S G; Zerbini, F Murilo

    2014-08-01

    Viral diseases caused by begomoviruses are of economic importance due to their adverse effects on the production of tropical and subtropical crops. In Ecuador, despite reports of significant infestations of Bemisia tabaci in the late 1990s, only very recently has a begomovirus, tomato leaf deformation virus (ToLDeV, also present in Peru), been reported in tomato. ToLDeV is the first monopartite begomovirus discovered that originated in the Americas, and its presence in Ecuador highlights the need for a wider survey of tomato-infecting begomoviruses in this country. Tomato and weed samples were collected in 2010 and 2011 in six provinces of Ecuador, and begomovirus genomes were cloned and sequenced using a rolling-circle-amplification-based approach. Most tomato samples from the provinces of Guayas, Loja, Manabi and Santa Elena were infected with tomato leaf deformation virus (ToLDeV). One sample from Manabi had a triple infection with ToLDeV, rhynchosia golden mosaic Yucatan virus (RhGMYuV) and an isolate that was a recombinant between the two. A new begomovirus was detected in another tomato sample from Manabi. Samples of Rhynchosia sp. from the provinces of Guayas and Manabi were infected by RhGMYuV. These results indicate not only the prevalence of ToLDeV in tomato in Ecuador but also the presence of other viruses, albeit at a much lower frequency.

  20. Manufacturing Demonstration Facility: Roll-to-Roll Processing

    SciTech Connect

    Datskos, Panos G; Joshi, Pooran C; List III, Frederick Alyious; Duty, Chad E; Armstrong, Beth L; Ivanov, Ilia N; Jacobs, Christopher B; Graham, David E; Moon, Ji Won

    2015-08-01

    This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean room facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.

  1. Body roll in swimming: a review.

    PubMed

    Psycharakis, Stelios G; Sanders, Ross H

    2010-02-01

    In this article, we present a critical review of the swimming literature on body roll, for the purposes of summarizing and highlighting existing knowledge, identifying the gaps and limitations, and stimulating further research. The main research findings can be summarized as follows: swimmers roll their shoulders significantly more than their hips; swimmers increase hip roll but maintain shoulder roll when fatigued; faster swimmers roll their shoulders less than slower swimmers during a 200-m swim; roll asymmetries, temporal differences in shoulder roll and hip roll, and shoulder roll side dominance exist in front crawl swimming, but there is no evidence to suggest that they affect swimming performance; and buoyancy contributes strongly to generating body roll in front crawl swimming. Based on and stimulated by current knowledge, future research should focus on the following areas: calculation of body roll for female swimmers and for backstroke swimming; differences in body roll between breathing and non-breathing cycles; causes of body roll asymmetries and their relation to motor laterality; body roll analysis across a wide range of velocities and swimming distances; exploration of the association between body roll and the magnitude and direction of propulsive/resistive forces developed during the stroke cycle; and the influence of kicking actions on the generation of body roll. PMID:20131140

  2. Body roll in swimming: a review.

    PubMed

    Psycharakis, Stelios G; Sanders, Ross H

    2010-02-01

    In this article, we present a critical review of the swimming literature on body roll, for the purposes of summarizing and highlighting existing knowledge, identifying the gaps and limitations, and stimulating further research. The main research findings can be summarized as follows: swimmers roll their shoulders significantly more than their hips; swimmers increase hip roll but maintain shoulder roll when fatigued; faster swimmers roll their shoulders less than slower swimmers during a 200-m swim; roll asymmetries, temporal differences in shoulder roll and hip roll, and shoulder roll side dominance exist in front crawl swimming, but there is no evidence to suggest that they affect swimming performance; and buoyancy contributes strongly to generating body roll in front crawl swimming. Based on and stimulated by current knowledge, future research should focus on the following areas: calculation of body roll for female swimmers and for backstroke swimming; differences in body roll between breathing and non-breathing cycles; causes of body roll asymmetries and their relation to motor laterality; body roll analysis across a wide range of velocities and swimming distances; exploration of the association between body roll and the magnitude and direction of propulsive/resistive forces developed during the stroke cycle; and the influence of kicking actions on the generation of body roll.

  3. Rolling Process Modeling Report: Finite-Element Prediction of Roll Separating Force and Rolling Defects

    SciTech Connect

    Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas

    2014-04-23

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate-type fuel for the U.S. high-performance research reactors. This work supports the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll separating forces and rolling defects. Simulations were performed using a finite-element model developed using the commercial code LS-Dyna. Simulations of the hot rolling of U-10Mo coupons encapsulated in low-carbon steel have been conducted following two different schedules. Model predictions of the roll-separation force and roll-pack thicknesses at different stages of the rolling process were compared with experimental measurements. This report discusses various attributes of the rolled coupons revealed by the model (e.g., dog-boning and thickness non-uniformity).

  4. Hot rolling of thick uranium molybdenum alloys

    SciTech Connect

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  5. The rolling-circle melting-pot model for porcine circovirus DNA replication

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A stem-loop structure, formed by a pair of inverted repeats during DNA replication, is a conserved feature at the origin of DNA replication (Ori) among plant and animal viruses, bacteriophages and plasmids that replicate their genomes via the rolling-circle replication (RCR) mechanism. Porcine circo...

  6. Identification of extrachromosomal circular DNA in hop via rolling circle amplification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a survey looking for viruses affecting hop plants in the Willamette Valley of Oregon, a circular DNA molecule was identified via rolling circle amplification (RCA) and later characterized. The 5.7 kb long molecule only matched in a minor cover to a microsatellite region in the Humulus lupulus...

  7. 14 CFR 25.349 - Rolling conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...(b): (1) Conditions corresponding to steady rolling velocities must be investigated. In addition... rolling velocity may be assumed in the absence of a rational time history investigation of the...

  8. QTL analysis of disease resistance to leaf spots and TSWV in peanut (Arachis hypogaea)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early leaf spot (ELS), caused by Cercospora arachidicola, late leaf spot (LLS), caused by Cercosporidium personatum, and Tomato spotted wilt virus (TSWV) result in great losses in yield in peanut (Arachis hypogaea L.). In order to identify quantitative trait loci (QTL) for resistance to these dise...

  9. Diversity, Mutation and Recombination Analysis of Cotton Leaf Curl Geminiviruses

    PubMed Central

    Saleem, Huma; Nahid, Nazia; Shakir, Sara; Ijaz, Sehrish; Murtaza, Ghulam; Khan, Asif Ali; Mubin, Muhammad; Nawaz-ul-Rehman, Muhammad Shah

    2016-01-01

    The spread of cotton leaf curl disease in China, India and Pakistan is a recent phenomenon. Analysis of available sequence data determined that there is a substantial diversity of cotton-infecting geminiviruses in Pakistan. Phylogenetic analyses indicated that recombination between two major groups of viruses, cotton leaf curl Multan virus (CLCuMuV) and cotton leaf curl Kokhran virus (CLCuKoV), led to the emergence of several new viruses. Recombination detection programs and phylogenetic analyses showed that CLCuMuV and CLCuKoV are highly recombinant viruses. Indeed, CLCuKoV appeared to be a major donor virus for the coat protein (CP) gene, while CLCuMuV donated the Rep gene in the majority of recombination events. Using recombination free nucleotide datasets the substitution rates for CP and Rep genes were determined. We inferred similar nucleotide substitution rates for the CLCuMuV-Rep gene (4.96X10-4) and CLCuKoV-CP gene (2.706X10-4), whereas relatively higher substitution rates were observed for CLCuMuV-CP and CLCuKoV-Rep genes. The combination of sequences with equal and relatively low substitution rates, seemed to result in the emergence of viral isolates that caused epidemics in Pakistan and India. Our findings also suggest that CLCuMuV is spreading at an alarming rate, which can potentially be a threat to cotton production in the Indian subcontinent. PMID:26963635

  10. 14 CFR 23.349 - Rolling conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rolling conditions. 23.349 Section 23.349... Rolling conditions. The wing and wing bracing must be designed for the following loading conditions: (a..., the rolling accelerations may be obtained by modifying the symmetrical flight conditions in §...

  11. Rolling Wrinkles on Elastic Substrates

    NASA Astrophysics Data System (ADS)

    Imburgia, Michael; Crosby, Alfred

    The mechanics of rolling contact between an elastomer layer and a thin film present unique opportunities for taking advantage of elastic instabilities, such as surface wrinkling, to create patterned surfaces. Here we present a plate-to-roll(P2R) geometry to laminate a thin film onto an elastomer layer in order to induce surface wrinkling. First, a poly(dimethylsiloxane)(PDMS) layer is draped around a roller and pressed into contact with a poly(styrene)(PS) film supported on a plate. Once rolling begins, the PS film preferentially laminates onto the PDMS layer. During this process, the deformation of the PDMS layer can induce wrinkling when the contact load exceeds a critical value. Wrinkle feature size consists of amplitudes of 0 . 2 - 4 μm and wavelengths of 15 - 20 μm . Wrinkle amplitude can be controlled by contact load and roller curvature, as well as the mechanical properties and thickness of the film and elastomer. We develop semi-empirical equations to describe the effect of contact load and roller curvature on the wrinkle aspect ratio. Finite-element modeling of an elastomer layer in rolling contact with a rigid plate is used to support experimental results. Using these models, wrinkle-based technologies such as optoelectronics and enhanced adhesives can be envisioned.

  12. Leaf growth is conformal

    NASA Astrophysics Data System (ADS)

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I.; Boudaoud, Arezki

    2016-10-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  13. Leaf growth is conformal.

    PubMed

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour. PMID:27597439

  14. Cell-free construction of disarmed Abutilon mosaic virus-based gene silencing vectors.

    PubMed

    Krenz, Björn; Wege, Christina; Jeske, Holger

    2010-10-01

    The bipartite Abutilon mosaic virus (AbMV) was engineered as a versatile silencing vector in which the coat protein gene of DNA A was deleted and replaced by sequences of interest. Plants transgenic for the dimeric AbMV DNA B component were used as test hosts to minimize the risk of unintended release of the recombinant DNA. The vector construct was stable genetically upon systemic infection and, in common with the parental virus, the vector remained phloem-limited. For virus-induced gene silencing (VIGS), a phytoene desaturase gene fragment was isolated from Nicotiana benthamiana (NbPDS) and inserted into the vector. After agroinfection, phytoene desaturase silencing was triggered efficiently in all leaf tissues without interference by viral symptoms. In order to facilitate further the use of the system, a technique for cell-free construction of recombinants was established using rolling circle amplification and biolistic inoculation of DNA B-transgenic plants. This novel procedure provides a convenient and safe way for delivering VIGS constructs for functional genomics. PMID:20638413

  15. A rolling 3-UPU parallel mechanism

    NASA Astrophysics Data System (ADS)

    Miao, Zhihuai; Yao, Yan'an; Kong, Xianwen

    2013-12-01

    A novel rolling mechanism is proposed based on a 3-UPU parallel mechanism in this paper. The rolling mechanism is composed of two platforms connected by three UPU (universal-prismatic-universal) serial-chain type limbs. The degree-of-freedom of the mechanism is analyzed using screw theory. Gait analysis and stability analysis are presented in detail. Four rolling modes of the mechanism are discussed and simulated. The feasibility of the rolling mechanism is verified by means of a physical prototype. Finally, its terrain adaptability is enhanced through planning the rolling gaits.

  16. [Roll repair of nonconfluent pulmonary artery].

    PubMed

    Komiya, T; Yamazaki, K; Kohchi, K; Kanzaki, Y

    1995-11-01

    We reviewed the repair of nonconfluent pulmonary artery using a roll to clarify indication of this operation, operative technique (especially the material and the size of conduit) and possibility of total correction. Eleven patients (mean age: five years) and 13 operations including two reoperations were reviewed. The material of the roll was xenopericardium in nine and artificial graft in four operations. No operative death and late death occurred. Five patients required reoperations from three occlusion and two severe stenosis of the roll. Three of nine xenopericardial roll needed reoperations and in two reoperated cases, the roll had been placed behind the aorta. In contrast, one artificial graft needed reoperation. The diameter of the roll was compared with that of normal pulmonary artery estimated from the body surface area. If the roll was too large (more than 125% normal) or too small (less than 100% normal), the luminal diameter of the roll became significantly smaller than appropriate-sized roll (p = 0.002). The size of nonconfluent side of the pulmonary artery also affect the result of repair. In occluded or stenotic cases, the unilateral PA index was significantly smaller than good patent cases (p = 0.014). Total correction was possible in eight cases (73%) including four Rastelli operation, two right ventricular outflow patch enlargement, and two modified Fontan operations without operative death. Thus preoperative evaluation of the pulmonary artery size and anatomy, selection of roll material and size matching seemed to be important for successful roll repair of nonconfluent pulmonary artery.

  17. Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls--Application to TiN-Coated Rolls

    SciTech Connect

    Ould, Choumad; Montmitonnet, Pierre; Gachon, Yves; Badiche, Xavier

    2011-05-04

    Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer (''roll coating'', ''pick up'') may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

  18. Deer predation on leaf miners via leaf abscission

    NASA Astrophysics Data System (ADS)

    Yamazaki, Kazuo; Sugiura, Shinji

    2008-03-01

    The evergreen oak Quercus gilva Blume sheds leaves containing mines of the leaf miner Stigmella sp. (Lepidoptera: Nepticulidae) earlier than leaves with no mines in early spring in Nara, central Japan. The eclosion rates of the leaf miner in abscised and retained leaves were compared in the laboratory to clarify the effects of leaf abscission on leaf miner survival in the absence of deer. The leaf miner eclosed successfully from both fallen leaves and leaves retained on trees. However, sika deer ( Cervus nippon centralis Kishida) feed on the fallen mined leaves. Field observations showed that deer consume many fallen leaves under Q. gilva trees, suggesting considerable mortality of leaf miners due to deer predation via leaf abscission. This is a previously unreported relationship between a leaf miner and a mammalian herbivore via leaf abscission.

  19. Slow-roll thawing quintessence

    SciTech Connect

    Chiba, Takeshi

    2009-04-15

    We derive slow-roll conditions for thawing quintessence. We solve the equation of motion of {phi} for a Taylor expanded potential (up to the quadratic order) in the limit where the equation of state w is close to -1 to derive the equation of state as a function of the scale factor. We find that the evolution of {phi} and hence w are described by only two parameters. The expression for w(a), which can be applied to general thawing models, coincides precisely with that derived recently by Dutta and Scherrer for hilltop quintessence. The consistency conditions of |w+1|<<1 are derived. The slow-roll conditions for freezing quintessence are also derived.

  20. Slow-roll extended quintessence

    SciTech Connect

    Chiba, Takeshi; Siino, Masaru; Yamaguchi, Masahide

    2010-04-15

    We derive the slow-roll conditions for a nonminimally coupled scalar field (extended quintessence) during the radiation/matter dominated era extending our previous results for thawing quintessence. We find that the ratio {phi}e/3H{phi} becomes constant but negative, in sharp contrast to the ratio for the minimally coupled scalar field. We also find that the functional form of the equation of state of the scalar field asymptotically approaches that of the minimally coupled thawing quintessence.

  1. Mechanisms of rolling contact spalling

    NASA Technical Reports Server (NTRS)

    Kumar, A. M.; Kulkarni, S. M.; Bhargava, V.; Hahn, G. T.; Rubin, C. A.

    1987-01-01

    The results of a study aimed at analyzing the mechanical material interactions responsible for rolling contact spalling of the 440 C steel, high pressure oxygen turbopump bearings are presented. A coupled temperature displacement finite element analysis of the effects of friction heating under the contact is presented. The contact is modelled as a stationary, heat generating, 2 dimensional indent in an elastic perfectly plastic half-space with heat fluxes up to 8.6 x 10000 KW/m sq comparable to those generated in the bearing. Local temperatures in excess of 1000 C are treated. The calculations reveal high levels of residual tension after the contact is unloaded and cools. Efforts to promote Mode 2/Mode 3 fatigue crack growth under cyclic torsion in hardened 440 C steel are described. Spalls produced on 440 C steel by a 3 ball/rod rolling contact testing machine were studied with scanning microscopy. The shapes of the cyclic, stress strain hysteresis loops displayed by hardened 440 C steel in cyclic torsion at room temperature are defined for the plastic strain amplitudes encountered in rolling/sliding contact. Results of these analyses are discussed in detail.

  2. Rolling Contact Fatigue of Ceramics

    SciTech Connect

    Wereszczak, Andrew A; Wang, W.; Wang, Y.; Hadfield, M.; Kanematsu, W.; Kirkland, Timothy Philip; Jadaan, Osama M.

    2006-09-01

    High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

  3. Damped leaf flexure hinge

    NASA Astrophysics Data System (ADS)

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage.

  4. Damped leaf flexure hinge.

    PubMed

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage. PMID:26026549

  5. Occurrence of Apple stem grooving virus in commercial apple seedlings and analysis of its coat protein sequence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virus infections are responsible for reduced yield and quality in many crops, and are especially problematic in vegetatively-propagated crops such as apple. Three major viruses (Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus and Apple stem pitting virus) affect apple trees in Kore...

  6. Anti-Herpetic Activity of Callissia fragrans and Simmondsia chinensis Leaf Extracts In Vitro

    PubMed Central

    Yarmolinsky, Ludmila; Zaccai, Michele; Ben-Shabat, Shimon; Huleihel, Mahmoud

    2010-01-01

    The antiviral activity of Callissia fragrans and Simnondsia chinensis aquatic and ethanol leaf extracts, as well as purified fractions from these extracts was studied against herpetic viruses in vitro. Ethanol extract of C. fragrans effectively inhibited the infection of Vero cells by HSV-1, HSV-2 in vitro, while its aquatic extract inhibited only VZV. Although S. chinensis leaf extract strongly inhibited all studied viruses, the selectivity index of this extract was very low, due to its high toxicity. However, the majority of its fractions showed low toxicity and higher antiviral activity and therefore very high SI. Strong interactions between virus and extracts were found. PMID:20700398

  7. Helitrons on a roll: eukaryotic rolling-circle transposons.

    PubMed

    Kapitonov, Vladimir V; Jurka, Jerzy

    2007-10-01

    Rolling-circle eukaryotic transposons, known as Helitron transposons, were first discovered in plants (Arabidopsis thaliana and Oryza sativa) and in the nematode Caenorhabditis elegans. To date, Helitrons have been identified in a diverse range of species, from protists to mammals. They represent a major class of eukaryotic transposons and are fundamentally different from classical transposons in terms of their structure and mechanism of transposition. Helitrons seem to have a major role in the evolution of host genomes. They frequently capture diverse host genes, some of which can evolve into novel host genes or become essential for helitron transposition.

  8. How rolling forecasting facilitates dynamic, agile planning.

    PubMed

    Miller, Debra; Allen, Michael; Schnittger, Stephanie; Hackman, Theresa

    2013-11-01

    Rolling forecasting may be used to replace or supplement the annual budget process. The rolling forecast typically builds on the organization's strategic financial plan, focusing on the first three years of plan projections and comparing the strategic financial plan assumptions with the organization's expected trajectory. Leaders can then identify and respond to gaps between the rolling forecast and the strategic financial plan on an ongoing basis.

  9. Structure of large dsDNA viruses

    PubMed Central

    Klose, Thomas; Rossmann, Michael G.

    2015-01-01

    Nucleocytoplasmic large dsDNA viruses (NCLDVs) encompass an ever-increasing group of large eukaryotic viruses, infecting a wide variety of organisms. The set of core genes shared by all these viruses includes a major capsid protein with a double jelly-roll fold forming an icosahedral capsid, which surrounds a double layer membrane that contains the viral genome. Furthermore, some of these viruses, such as the members of the Mimiviridae and Phycodnaviridae have a unique vertex that is used during infection to transport DNA into the host. PMID:25003382

  10. Spray Rolling Aluminum Strip for Transportation Applications

    SciTech Connect

    Kevin M. McHugh; Y. Lin; Y. Zhou; E. J. Lavernia; J.-P. Delplanque; S. B. Johnson

    2005-02-01

    Spray rolling is a novel strip casting technology in which molten aluminum alloy is atomized and deposited into the roll gap of mill rolls to produce aluminum strip. A combined experimental/modeling approach has been followed in developing this technology with active participation from industry. The feasibility of this technology has been demonstrated at the laboratory scale and it is currently being scaled-up. This paper provides an overview of the process and compares the microstructure and properties of spray-rolled 2124 aluminum alloy with commercial ingot-processed material

  11. METHOD OF HOT ROLLING URANIUM METAL

    DOEpatents

    Kaufmann, A.R.

    1959-03-10

    A method is given for quickly and efficiently hot rolling uranium metal in the upper part of the alpha phase temperature region to obtain sound bars and sheets possessing a good surface finish. The uranium metal billet is heated to a temperature in the range of 1000 deg F to 1220 deg F by immersion iii a molten lead bath. The heated billet is then passed through the rolls. The temperature is restored to the desired range between successive passes through the rolls, and the rolls are turned down approximately 0.050 inch between successive passes.

  12. Purification of tomato yellow leaf curl geminivirus.

    PubMed

    Luisoni, E; Milne, R G; Vecchiati, M

    1995-07-01

    Attempts were made to find a good purification procedure for tomato yellow leaf curl virus (TYLCV), a dangerous and continuously spreading whitefly-transmitted germinivirus, up to now only partially purified. Electron microscopy, serology and spectrophotometry were used to evaluate different procedures. The scheme finally adopted was the following: collect leaves and stems from Nicotiana benthamiana graft-infected 45-60 days previously (5-10 g/plant); homogenize with 0.5 M phosphate buffer pH 6 containing 2.5 mM NaEDTA, 10 mM Na2SO3, 0.1% 2-mercaptoethanol, 1% Triton X-100 and 0.1% Driselase (3-4 ml of buffer for each g of material); incubate overnight on ice with gentle agitation; filter; emulsify with 15% cold chloroform; centrifuge at low speed; ultracentrifuge supernatant; resuspend pellets in 0.5 M phosphate buffer pH 7 containing 2.5 mM NaEDTA; centrifuge at low speed; repeat resuspension of the pellets and low-speed centrifugation; ultracentrifuge the pooled supernatant on a Cs2SO4 gradient (e.g. for 5 h at 41,000 rpm); collect the virus band and dialyse or ultracentrifuge the virus. The virus yield was 5-10 mg per kg of tissue. PMID:7553359

  13. Effect of temper rolling on final shape defects in a V-section roll forming process

    NASA Astrophysics Data System (ADS)

    Abvabi, Akbar; Rolfe, Bernard; Hodgson, Peter D.; Weiss, Matthias

    2013-12-01

    Roll forming is a continuous process in which a flat strip is shaped to the desired profile by sequential bending in a series of roll stands. Because of the large variety of applications of roll forming in the industry, Finite Element Analysis (FEA) is increasingly utilized for roll forming process design. Bending is the dominant deformation mode in roll forming. Sheet materials used in this process are generally temper rolled, roller- or tension- leveled. These processes introduce residual stresses into the material, and recent studies have shown that those affect the material behavior in bending. In this study a numerical model of the temper rolling (skin passing) process was used to determine a residual stress distribution in a dual phase, DP780, steel strip. A 5-stand roll forming process for the forming of a V-section was modeled, and the effect of various thickness reduction levels in the temper rolling process on the final shape defects was analyzed. The results show that a small thickness reduction in the temper rolling process decreases the maximum bow height but the final springback angle increases. It is also shown that reasonable model accuracy can be achieved by including the residual stress information due to temper rolling as initial condition in the numerical modeling of a roll forming process.

  14. Further Insights Into The Epidemiology And Monitoring Practices Of Tomato Viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are a number of serious virus threats to tomato production in Florida. These include the whitefly-transmitted Tomato yellow leaf curl virus (TYLCV) and, more recently, Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV) which are both vectored by thrips. GRSV and TCSV are cl...

  15. Rolling-cuff flexible bellows

    DOEpatents

    Lambert, D.R.

    1982-09-27

    A flexible connector apparatus used to join two stiff non-deformable members, such as piping, is described. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

  16. Maple Leaf Outdoor Centre.

    ERIC Educational Resources Information Center

    Maguire, Molly; Gunton, Ric

    2000-01-01

    Maple Leaf Outdoor Centre (Ontario) has added year-round outdoor education facilities and programs to help support its summer camp for disadvantaged children. Schools, youth centers, religious groups, and athletic teams conduct their own programs, collaborate with staff, or use staff-developed programs emphasizing adventure education and personal…

  17. Bacterial leaf spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial leaf spot has been reported in Australia (Queensland), Egypt, El Salvador, India, Japan, Nicaragua, Sudan, and the United States (Florida, Iowa, Kansas, Maryland, and Wisconsin). It occasionally causes locally severe defoliation and post-emergence damping-off and stunting. The disease is...

  18. Comparative leaf development in angiosperms.

    PubMed

    Tsukaya, Hirokazu

    2014-02-01

    Recent accumulation of our knowledge on basic leaf development mechanisms in model angiosperm species has allowed us to pursue evolutionary development (evo/devo) studies of various kinds of leaf development. As a result, unexpected findings and clues have been unearthed aiding our understanding of the mechanisms involved in the diversity of leaf morphology, although the covered remain limited. In this review, we highlight recent findings of diversified leaf development in angiosperms.

  19. 1. EXTERIOR VIEW OF BUILDING THAT HOUSES THE HOT ROLL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR VIEW OF BUILDING THAT HOUSES THE HOT ROLL MILL, ALSO KNOWN AS THE NO. 31 HOT ROLL MILL; LOOKING SOUTHWEST - American Brass Company, Kenosha Works, Hot Roll Mill, Kenosha, Kenosha County, WI

  20. Dynamic precipitation of Al-Zn alloy during rolling and accumulative roll bonding

    NASA Astrophysics Data System (ADS)

    Liu, C. Y.; Yu, L.; Ma, M. Z.; Liu, R. P.; Ma, Z. Y.

    2015-11-01

    In this study, cold rolling was performed on a binary Al-20 wt%Zn alloy and dynamic precipitation identified for the first time in Al alloys under cold rolling. Zn clusters formed after application of 0.6 strain, and the Zn phase precipitated upon further increasing strain. Both grain refinement and rolling-induced defects are considered to promote Zn precipitation. The hardness of Al-Zn alloy initially increased with strain up to a strain of 2.9 and then decreased with increasing rolling strain. Dynamic precipitation greatly affects the strengthening mechanism of the rolled Al-Zn alloy under various strains.

  1. 14 CFR 25.349 - Rolling conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.349 Rolling conditions. The airplane must be designed for loads resulting from the rolling conditions specified in... deflections may be limited by pilot effort) must be considered in combination with an airplane load factor...

  2. 14 CFR 25.349 - Rolling conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.349 Rolling conditions. The airplane must be designed for loads resulting from the rolling conditions specified in... deflections may be limited by pilot effort) must be considered in combination with an airplane load factor...

  3. 14 CFR 25.349 - Rolling conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.349 Rolling conditions. The airplane must be designed for loads resulting from the rolling conditions specified in... deflections may be limited by pilot effort) must be considered in combination with an airplane load factor...

  4. 14 CFR 25.349 - Rolling conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.349 Rolling conditions. The airplane must be designed for loads resulting from the rolling conditions specified in... deflections may be limited by pilot effort) must be considered in combination with an airplane load factor...

  5. Lubrication of rolling-element bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1980-01-01

    The lubrication of rolling element bearings is surveyed. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through the race are discussed. The historical development, present state of technology, and the future problems of rolling element bearing lubrication are discussed.

  6. Roll forming of eco-friendly stud

    NASA Astrophysics Data System (ADS)

    Keum, Y. T.; Lee, S. Y.; Lee, T. H.; Sim, J. K.

    2013-12-01

    In order to manufacture an eco-friendly stud, the sheared pattern is designed by the Taguchi method and expanded by the side rolls. The seven geometrical shape of sheared pattern are considered in the structural and thermal analyses to select the best functional one in terms of the durability and fire resistance of dry wall. For optimizing the size of the sheared pattern chosen, the L9 orthogonal array and smaller-the-better characteristics of the Taguchi method are used. As the roll gap causes forming defects when the upper-and-lower roll type is adopted for expanding the sheared pattern, the side roll type is introduced. The stress and strain distributions obtained by the FEM simulation of roll-forming processes are utilized for the design of expanding process. The expanding process by side rolls shortens the length of expanding process and minimizes the cost of dies. Furthermore, the stud manufactured by expanding the sheared pattern of the web is an eco-friend because of the scrapless roll-forming process. In addition, compared to the conventionally roll-formed stud, the material cost is lessened about 13.6% and the weight is lightened about 15.5%.

  7. 42 CFR 21.46 - Merit roll.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Merit roll. 21.46 Section 21.46 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL COMMISSIONED OFFICERS Appointment § 21.46 Merit roll. Each board appointed pursuant to § 21.30 to consider the qualifications...

  8. Computational Analysis of Ares I Roll Control System Jet Interaction Effects on Rolling Moment

    NASA Technical Reports Server (NTRS)

    Deere, Karen A.; Pao, S. Paul; Abdol-Hamid, Khaled S.

    2011-01-01

    The computational flow solver USM3D was used to investigate the jet interaction effects from the roll control system on the rolling moment of the Ares I full protuberance configuration at wind tunnel Reynolds numbers. Solutions were computed at freestream Mach numbers from M = 0.5 to M = 5 at the angle of attack 0deg, at the angle of attack 3.5deg for a roll angle of 120deg, and at the angle of attack 7deg for roll angles of 120deg and 210deg. Results indicate that the RoCS housing provided a beneficial jet interaction effect on vehicle rolling moment for M > or = 0.9. Most of the components downstream of the roll control system housing contributed to jet interaction penalties on vehicle rolling moment.

  9. High efficient of females of B-type Bemisia tabaci as males in transmitting the whitefly-borne tomato yellow leaf curl virus to tomato plant with Q-PCR method confirmation.

    PubMed

    Xie, Wen; Xu, Yan-Xia; Jiao, Xiao-Guo; Zhang, You-Jun

    2012-11-01

    It has been previously reported that TYLCV can be transmitted from viruliferous males to non-viruliferous females and from viruliferous females to non-viruliferous males, but not between insects of the same sex; female whiteflies transmit TYLCV-Is with higher efficiency than males through symptoms recognition and viral DNA identification in tomato test plants (one insect per plant, with 48 h AAP and 48 h IAP). However, it remains unclear whether non-infected female and male could obtain same virus from TYLCV-infected tomato plants, and whether TYLCV-infected female and male could transmit same virus to non-viruliferous tomato plants. To address this issue, quantitative real-time PCR were applied to detect TYLCV content in adults or tomato plant. The acquisition and transmission experiments showed that both female and male can acquire and transmit the virus and no acquisition capability difference was observed between newly emerged female and male, however, female demonstrated superior transmission capability than male. Moreover, gene expressions profilings of GroEL and Hamiltonella in non-viruliferous and viruliferous female was all higher than that in male. These results further indicated that sex is an important factor affecting TYLCV transmission efficiency in B. tabaci. PMID:23336021

  10. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  11. A multiple reverse transcription-polymerase chain reaction assay for simultaneous detection and differentiation of latent viruses and apscarviroids in apple trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV), and Apple stem pitting virus (ASPV) are three latent viruses frequently occurring in apple trees worldwide. In field orchards, these viruses are frequently found in a mixed infection with viroids in the genus Apscarviroid, in...

  12. Inflation with a constant rate of roll

    NASA Astrophysics Data System (ADS)

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2015-09-01

    We consider an inflationary scenario where the rate of inflaton roll defined by ̈phi/H dot phi remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of 'constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime.

  13. Analysis of acid-extractable tomato leaf proteins after infection with a viroid, two viruses and a fungus and partial purification of the "pathogenesis-related" protein p 14.

    PubMed

    Camacho Henriquez, A; Sänger, H L

    1982-01-01

    Gel electrophoretic analysis revealed marked alterations in the pattern of acid-extractable proteins from tomato leaves after infection with a viroid (PSTV), two viruses [tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV)], and a fungus (Cladosporium fulvum) when compared to the pattern from healthy leaves. A pathogen-specific appearance of new protein bands was only found after infection with TMV (MW 17,400 and 65,000), CMV (MW 9000 and 8000) and Cladosporium fulvum (MW 28,000). With the exception of the TMV coat protein (MW 17,400) it could not be established whether the other four proteins are coded for by the corresponding pathogen or by the host. Nine proteins with the apparent NW of 10,000, 11,000, 12,000, 13,000, 14,000, 25,000, 31,000, 33,000 and 38,000 showed an increase in their relative concentration which is most dramatic in the case of the protein with the MW of 14,000 called p14. A decrease was observed in four proteins with molecular weights of 14,500, 23,000, 30,000 and 105,000. Since all these alterations could be correlated with the severity of the disease symptoms but not with the nature of the pathogen they must be considered as a general pathophysiological response of the tomato plant to infection and symptom development. A partial purification of the most prominent "pathogenesis-related" protein p14 from tomato plants is described. PMID:6891893

  14. Incidence of sweet cherry viruses in Shandong Province, China and a case study on multiple infection with five viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To investigate the occurrence of viruses in sweet cherry in China, leaf samples displaying leaf necrotic lesions or chlorotic spots were collected from trees in six orchards in the Shandong province. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that Prunus necrotic rin...

  15. Signal and power roll ring testing update

    NASA Technical Reports Server (NTRS)

    Smith, Dennis W.

    1989-01-01

    The development of the roll ring as a long-life, low-torque alternative to the slip ring is discussed. A roll ring consists of one or more circular flexures captured by their own spring force in the annular space between two concentric conductors or contact rings. The advantages of roll rings over other types of electrical transfer devices are: extremely low drag torque, high transfer efficiencies in high-power configurations, extremely low wear debris generation, long life, and low weight for high-power applications.

  16. Why Low Bounce Balls Exhibit High Rolling Resistance

    ERIC Educational Resources Information Center

    Cross, Rod

    2015-01-01

    A simple experiment is described to measure the coefficient of rolling friction for a low bounce ball rolling on a horizontal surface. As observed previously by others, the coefficient increased with rolling speed. The energy loss due to rolling friction can be explained in terms of the measured coefficient of restitution for the ball, meaning…

  17. 7 CFR 29.2528 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture Regulations...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  18. 7 CFR 29.3525 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  19. 7 CFR 29.1028 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  20. 7 CFR 29.3033 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  1. 9 CFR 381.159 - Poultry rolls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... subchapter, in 9 CFR Chapter III, Subchapter E, or in 21 CFR Chapter I, Subchapter A or Subchapter B. In... use as binders in poultry rolls: transglutaminase enzyme at up to 65 ppm. When binding agents...

  2. Mathematical modeling of deformation during hot rolling

    SciTech Connect

    Jin, D.; Stachowiak, R.G.; Samarasekera, I.V.; Brimacombe, J.K.

    1994-12-31

    The deformation that occurs in the roll bite during the hot rolling of steel, particularly the strain-rate and strain distribution, has been mathematically modeled using finite-element analysis. In this paper three different finite-element models are compared with one another and with industrial measurements. The first model is an Eulerian analysis based on the flow formulation method, while the second utilizes an Updated Lagrangian approach. The third model is based on a commercially available program DEFORM which also utilizes a Lagrangian reference frame. Model predictions of strain and strain-rate distribution, particularly near the surface of the slab, are strongly influenced by the treatment of friction at the boundary and the magnitude of the friction coefficient or shear factor. Roll forces predicted by the model have been compared with industrial rolling loads from a seven-stand hot-strip mill.

  3. Next-Generation Space Ambitions Keep Rolling

    NASA Video Gallery

    As space shuttle Atlantis rolled to its new home at the Kennedy Space Center Visitor Complex earlier this month, NASA and its commercial crew partners reflected on the Space Shuttle Program's treme...

  4. A Simple Modeling of Asymmetric Rolling

    NASA Astrophysics Data System (ADS)

    Halloumi, A.; Desrayaud, Ch.; Montheillet, F.

    2010-06-01

    Two complementary analytical approaches and the finite difference method are proposed for modeling asymmetric rolling (ASR) of metal sheet. The first analytical model is an upper bound method based on a uniform strain field depending on one single optimization parameter, viz. the entry velocity of the sheet. Its results can be straightforwardly used for practical applications. The second model uses a more refined analytical velocity field based on the classical parabolic estimation of the material flow lines in rolling. It involves an additional optimization parameter associated with the precise form of the velocity field. Local values of strain, strain rate and self-heating temperature are easily calculated, as well as the rolling force. Finally, the finite difference method is applied to compute heat transfers between the rolls and the sheet. In conclusion, the respective advantages of the three methods are discussed.

  5. A high sensitive roll angle interferometer

    NASA Astrophysics Data System (ADS)

    Le, Yanfen; Hou, Wenmei; Hu, Kai; Ju, Aisong

    2013-01-01

    A roll angle interferometer with high sensitivity is designed in this paper. Two sets of centrosymmetric beams are used to travel through the measurement and reference arms of the roll angle interferometer which contains two specific optical devices: wedge prism assembly and wedge mirror assembly. The optical path change in both arms caused by roll is converted into phase shift which can be measured by interferometer. Because of the adoption of the centrosymmetric measurement structure, the straightness errors, yaw error and pitch error can be avoided and the dead path is minimized, so that the stability and the accuracy of the measurement can be greatly enhanced. The resolution for the roll measurement is about 0.006″ with the measurement range of ±1°.

  6. Roll motion analysis of deepwater pipelay crane vessel

    NASA Astrophysics Data System (ADS)

    You, Dandan; Sun, Liping; Qu, Zhiguo; Wang, Tao

    2013-12-01

    For a large floating vessel in waves, radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion. Therefore, to get the knowledge of roll motion performance of deepwater pipelay crane vessels and to keep the vessel working safety, the paper presents the relationship between a series of dimensionless roll damping coefficients and the roll response amplitude operator (RAO). By using two kinds of empirical data, the roll damping is estimated in the calculation flow. After getting the roll damping coefficient from the model test, a prediction of roll motion in regular waves is evaluated. According to the wave condition in the working region, short term statistics of roll motion are presented under different wave parameters. Moreover, the relationship between the maximal roll response level to peak spectral wave period and the roll damping coefficient is investigated. Results may provide some reference to design and improve this kind of vessel.

  7. 75 FR 42782 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... party group responses to its notice of institution (75 FR 16504, April 1, 2010) were adequate. A record... COMMISSION Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia AGENCY: United...-year reviews concerning the countervailing duty order on certain hot-rolled flat-rolled...

  8. 49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a...

  9. 49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a...

  10. 49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a...

  11. 49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a...

  12. 49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a...

  13. Designing Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Moore, James D., Jr.

    2007-01-01

    Bearing Analysis Tool (BAT) is a computer program for designing rolling-element bearings for cryogenic turbomachines. BAT provides a graphical user interface (GUI) that guides the entry of data to develop mathematical models of bearings. The GUI breaks model data into logical subsets that are entered through logic-driven input screens. The software generates a threedimensional graphical model of a bearing as the data are entered. Most dataentry errors become immediately obvious in the graphical model. BAT provides for storage of all the data on a shaft/bearing system, enabling the creation of a library of proven designs. Data from the library can be transferred to subsequent projects by use of simple cut-and-paste routines. BAT includes a library of temperature- dependent cryogenic bearing-material properties for use in the mathematical models. BAT implements algorithms that (1) enable the user to select combinations of design and/or operating-condition parameters, and then (2) automatically optimize the design by performing trade studies over all of the parameter combinations. This feature enables optimization over a large trade space in a fraction of the time taken when using prior bearingmodel software.

  14. Strip edge cracking simulation in cold rolling

    SciTech Connect

    Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.

    2011-01-17

    This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

  15. Inactivated eastern equine encephalomyelitis vaccine propagated in rolling-bottle cultures of chick embryo cells.

    PubMed

    Cole, F E

    1971-11-01

    A method was developed for the production of Eastern equine encephalomyelitis vaccine from virus grown in rolling-bottle cultures (840 cm(2) growth area) of chick embryo cells. The PE-6 strain of virus was propagated in chick embryo cell roller cultures maintained on serum-free medium 199 containing 0.25% human serum albumin and antibiotics (MM). A multiplicity of inoculum of 0.005 yielded acceptable titers of virus at a convenient harvest time of 18 to 24 hr and reduced the carry-over of extraneous material from the virus seed. Growth studies in which 100, 200, or 300 ml of MM was used showed that use of 300 ml of MM offered two advantages: (i) cytopathic effects were less at the 18- to 24-hr harvest time, thereby decreasing cellular material in the final product, and (ii) total virus yield was not substantially reduced, thus permitting large-scale production of virus for further processing. Studies on formalin inactivation at 37 C indicated that the virus was inactivated by 0.05% formalin within 12 to 16 hr and with 0.1% formalin within 6 to 8 hr. Antigen extinction tests in hamsters revealed excellent potency (e.g., median-effective-dose values of 0.069 to 0.012 ml) for both fluid and freeze-dried products. The advantages of the roller-bottle technique in vaccine production are discussed.

  16. 40 CFR 1066.225 - Roll runout and diameter verification procedure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for roll runout and roll diameter. Roll runout is a measure of the variation in roll radius around the... position of the roll surface relative to the roll centerline as it turns through a complete revolution. The... dial indicator. (4) Slowly turn the roll through a complete rotation and record the maximum and...

  17. 40 CFR 1066.225 - Roll runout and diameter verification procedure.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for roll runout and roll diameter. Roll runout is a measure of the variation in roll radius around the... position of the roll surface relative to the roll centerline as it turns through a complete revolution. The... dial indicator. (4) Slowly turn the roll through a complete rotation and record the maximum and...

  18. Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations

    PubMed Central

    Heidari, Ali; Forouzan, Mohammad R.

    2012-01-01

    Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed. PMID:25685398

  19. Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations.

    PubMed

    Heidari, Ali; Forouzan, Mohammad R

    2013-01-01

    Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed.

  20. Comparing Acute Bouts of Sagittal Plane Progression Foam Rolling vs. Frontal Plane Progression Foam Rolling.

    PubMed

    Peacock, Corey A; Krein, Darren D; Antonio, Jose; Sanders, Gabriel J; Silver, Tobin A; Colas, Megan

    2015-08-01

    Many strength and conditioning professionals have included the use of foam rolling devices within a warm-up routine prior to both training and competition. Multiple studies have investigated foam rolling in regards to performance, flexibility, and rehabilitation; however, additional research is necessary in supporting the topic. Furthermore, as multiple foam rolling progressions exist, researching differences that may result from each is required. To investigate differences in foam rolling progressions, 16 athletically trained males underwent a 2-condition within-subjects protocol comparing the differences of 2 common foam rolling progressions in regards to performance testing. The 2 conditions included a foam rolling progression targeting the mediolateral axis of the body (FRml) and foam rolling progression targeting the anteroposterior axis (FRap). Each was administered in adjunct with a full-body dynamic warm-up. After each rolling progression, subjects performed National Football League combine drills, flexibility, and subjective scaling measures. The data demonstrated that FRml was effective at improving flexibility (p ≤ 0.05) when compared with FRap. No other differences existed between progressions.

  1. Practice of Improving Roll Deformation Theory in Strip Rolling Process Based on Boundary Integral Equation Method

    NASA Astrophysics Data System (ADS)

    Yuan, Zhengwen; Xiao, Hong; Xie, Hongbiao

    2014-02-01

    Precise strip-shape control theory is significant to improve rolled strip quality, and roll flattening theory is a primary part of the strip-shape theory. To improve the accuracy of roll flattening calculation based on semi-infinite body model, a new and more accurate roll flattening model is proposed in this paper, which is derived based on boundary integral equation method. The displacement fields of the finite length semi-infinite body on left and right sides are simulated by using finite element method (FEM) and displacement decay functions on left and right sides are established. Based on the new roll flattening model, a new 4Hi mill deformation model is established and verified by FEM. The new model is compared with Foppl formula and semi-infinite body model in different strip width, roll shifting value and bending force. The results show that the pressure and flattening between rolls calculated by the new model are more precise than other two models, especially near the two roll barrel edges.

  2. Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery

    SciTech Connect

    2001-10-01

    The project goal is to develop a numerical modeling capability to optimize the hot rolling process used to produce aluminum plate. This tool will be used in the forming process so that loss of product will be minimized. Product lost in the rolling process requires the energy-intensive steps of remelting and reforming into an ingot.

  3. First report of Pepper mottle virus infecting tomato in Hawaii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In August 2011, tomato (Solanum lycopersicum L.) fruit from a University of Hawaii field trial evaluating varietal resistance to Tomato spotted wilt virus (TSWV) and Tomato yellow leaf curl virus (TYLCV) displayed mottling symptoms similar to that caused by TSWV or other tospoviruses. The foliage f...

  4. Sensitivity analysis of roll load, torque and material properties in the roll forming process

    NASA Astrophysics Data System (ADS)

    Abeyrathna, Buddhika; Rolfe, Bernard; Hodgson, Peter; Weiss, Matthias

    2013-12-01

    Advanced High Strength Steel (AHSS) and Ultra High Strength Steel (UHSS) are increasingly used in the current automotive industry because of their high strength and weight saving potential. As a sheet forming process, roll forming is capable of forming such materials with precise dimensions, however a small change in processing may results in significant change in the material properties such as yield strength and hardening exponent from coil to coil or within the same coil. This paper presents the effect of yield strength and the hardening exponent on roll load, torque of the roll forming process and the longitudinal bow. The roll forming process is numerically simulated, and then the regression analysis and Analysis of Variance (ANOVA) techniques are employed to establish the relationships among the aforementioned parameters and to determine the percentage influence of material properties on longitudinal bow, roll load and torque.

  5. Improvement of vehicle roll stability by varying suspension properties

    NASA Astrophysics Data System (ADS)

    Shim, Taehyun; Velusamy, Pradheep C.

    2011-02-01

    Vehicle roll dynamics are strongly influenced by suspension properties such as roll centre height, roll steer, and roll camber. In this paper, the effects of suspension properties on vehicle roll response have been investigated using a multi-body vehicle dynamics programme. Roll dynamics of a vehicle model with MacPherson (front) and multilink (rear) suspensions were evaluated for the fishhook manoeuvre and variations of its roll response due to changes in the suspension properties were assessed by quantitatively analysing the vehicle response through simulation. Critical suspension design parameters for vehicle roll dynamics were identified and adjusted to improve roll stability of the vehicle model with passive suspension. Design of experiments has been used for identifying critical hardpoints affecting the suspension parameters, and optimisation techniques were employed for parameter optimisation. This approach provides a viable alternative to costlier active control systems for economy-class vehicles.

  6. Deep sequencing reveals a novel closterovirus associated with wild rose leaf rosette disease.

    PubMed

    He, Yan; Yang, Zuokun; Hong, Ni; Wang, Guoping; Ning, Guogui; Xu, Wenxing

    2015-06-01

    A bizarre virus-like symptom of a leaf rosette formed by dense small leaves on branches of wild roses (Rosa multiflora Thunb.), designated as 'wild rose leaf rosette disease' (WRLRD), was observed in China. To investigate the presumed causal virus, a wild rose sample affected by WRLRD was subjected to deep sequencing of small interfering RNAs (siRNAs) for a complete survey of the infecting viruses and viroids. The assembly of siRNAs led to the reconstruction of the complete genomes of three known viruses, namely Apple stem grooving virus (ASGV), Blackberry chlorotic ringspot virus (BCRV) and Prunus necrotic ringspot virus (PNRSV), and of a novel virus provisionally named 'rose leaf rosette-associated virus' (RLRaV). Phylogenetic analysis clearly placed RLRaV alongside members of the genus Closterovirus, family Closteroviridae. Genome organization of RLRaV RNA (17,653 nucleotides) showed 13 open reading frames (ORFs), except ORF1 and the quintuple gene block, most of which showed no significant similarities with known viral proteins, but, instead, had detectable identities to fungal or bacterial proteins. Additional novel molecular features indicated that RLRaV seems to be the most complex virus among the known genus members. To our knowledge, this is the first report of WRLRD and its associated closterovirus, as well as two ilarviruses and one capilovirus, infecting wild roses. Our findings present novel information about the closterovirus and the aetiology of this rose disease which should facilitate its control. More importantly, the novel features of RLRaV help to clarify the molecular and evolutionary features of the closterovirus.

  7. Patterns of Virus Distribution in Single and Mixed Infections of Florida Watermelons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whitefly-transmitted Squash vein yellowing virus (SqVYV) and Cucurbit leaf crumple virus (CuLCrV), and aphid-transmitted Papaya ringspot virus type W (PRSV-W) have had serious impact on watermelon production in southwest and west-central Florida in recent years. Tissue blot nucleic acid hybridizati...

  8. Patterns of Virus Distribution in Single and Mixed Infections of Florida Watermelons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whitefly-transmitted Squash vein yellowing virus (SqVYV) and Cucurbit leaf crumple virus (CuLCrV), and aphid-transmitted Papaya ringspot virus type W (PRSV-W) have had serious impact on watermelon production in southwest and west-central Florida in recent years. To determine the distribution of vir...

  9. Applying contextual interference to the Pawlata roll.

    PubMed

    Smith, P J; Davies, M

    1995-12-01

    Contextual interference is manipulated by changing the practice order of a number of similar motor tasks, so that the learning context of each interferes with that of the other. The effect has been found to generalize to baseball batting, badminton serving and volleyball skills. The present study examined whether this practice technique could be applied to a Pawlata roll in a kayak. The study was further motivated by the fact that many instructors in Britain currently advocate learning the Pawlata roll in one direction only to a criterion of accuracy, thereafter transferring to the opposite direction. Contextual interference literature predicts that skill retention would be better served by practising on alternate sides. Accordingly, 16 undergraduate students with no kayaking experience were randomly allocated to either a low contextual interference group, which followed U'ren's (1993) recommendations, or a high contextual interference group, which practised the skill on alternate sides. The high contextual interference group took less time to acquire the skill, and were also quicker to achieve successful performance in retention (full roll) and transfer (half roll) tests, regardless of the direction of the roll, 1 week later. The time savings in practice were not expected, as acquisition under high contextual interference was improved rather than impaired. This finding suggests that bilateral transfer was increased by randomizing practice. These results are worthy of further investigation, in that they suggest that the recommended training methods may not be optimal. PMID:8850571

  10. Applying contextual interference to the Pawlata roll.

    PubMed

    Smith, P J; Davies, M

    1995-12-01

    Contextual interference is manipulated by changing the practice order of a number of similar motor tasks, so that the learning context of each interferes with that of the other. The effect has been found to generalize to baseball batting, badminton serving and volleyball skills. The present study examined whether this practice technique could be applied to a Pawlata roll in a kayak. The study was further motivated by the fact that many instructors in Britain currently advocate learning the Pawlata roll in one direction only to a criterion of accuracy, thereafter transferring to the opposite direction. Contextual interference literature predicts that skill retention would be better served by practising on alternate sides. Accordingly, 16 undergraduate students with no kayaking experience were randomly allocated to either a low contextual interference group, which followed U'ren's (1993) recommendations, or a high contextual interference group, which practised the skill on alternate sides. The high contextual interference group took less time to acquire the skill, and were also quicker to achieve successful performance in retention (full roll) and transfer (half roll) tests, regardless of the direction of the roll, 1 week later. The time savings in practice were not expected, as acquisition under high contextual interference was improved rather than impaired. This finding suggests that bilateral transfer was increased by randomizing practice. These results are worthy of further investigation, in that they suggest that the recommended training methods may not be optimal.

  11. Leaf hydraulics II: vascularized tissues.

    PubMed

    Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

    2014-01-01

    Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements.

  12. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  13. Suppressors of RNA silencing encoded by tomato leaf curl betasatellites.

    PubMed

    Shukla, Richa; Dalal, Sunita; Malathi, V G

    2013-03-01

    Virus encoded RNA-silencing suppressors (RSSs) are the key components evolved by the viruses to counter RNA-silencing defense of plants. Whitefly-transmitted begomoviruses infecting tomato crop code for five different proteins, ORF AC4, ORF AC2 and ORF AV2 in DNA-A component, ORF BV1 in DNA-B and ORF beta C1 in satellite DNA beta which are predicted to function as silencing suppressors. In the present study suppressor function of ORF beta C1 of three betasatellites Tomato leaf curl Bangalore betasatellite ToLCBB-[IN:Hess:08], Cotton leaf curl Multan betasatellite CLCuMB-[IN:Sri:02] and Luffa leaf distortion betasatellite LuLDB-[IN:Lu:04] were examined. Agroinfiltration of GFP-silenced Nicotiana tabaccum cv. Xanthi with the cells expressing betaC1 protein resulted in reversal of silenced GFP expression. GFP-siRNA level was more than 50-fold lower compared to silenced plants in plants infiltrated with betaC1 gene from ToLCBB. However, in the case of 35S-beta C1 CLCuMB and 35S- beta C1 LuLDB construct, although GFP was expressed, siRNA level was not reduced, indicating that the step at which beta C1 interfere in RNA-silencing pathway is different. PMID:23385812

  14. Regulation of Compound Leaf Development

    PubMed Central

    Wang, Yuan; Chen, Rujin

    2013-01-01

    Leaf morphology is one of the most variable, yet inheritable, traits in the plant kingdom. How plants develop a variety of forms and shapes is a major biological question. Here, we discuss some recent progress in understanding the development of compound or dissected leaves in model species, such as tomato (Solanum lycopersicum), Cardamine hirsuta and Medicago truncatula, with an emphasis on recent discoveries in legumes. We also discuss progress in gene regulations and hormonal actions in compound leaf development. These studies facilitate our understanding of the underlying regulatory mechanisms and put forward a prospective in compound leaf studies. PMID:27135488

  15. Rolling bearing stiffness in arbitrary direction

    NASA Astrophysics Data System (ADS)

    Luo, Zhusan; Sun, Xinde; Wu, Linfeng

    1992-06-01

    This paper presents a new concept of rolling bearing stiffness in arbitrary direction, which is necessary to the investigation of rotor-bearing dynamics. It includes the axial stiffness and the arbitrary radial stiffness of the rolling bearing. Based on elasticity theory and the geometrical parameters of the bearing, the approximate formulas of the axial stiffness, the arbitrary radial stiffness, and the inner ring displacements are derived. Furthermore, the paper also discusses the effects of the loads, the radial clearance, and the load distribution parameters on the rolling bearing stiffness. In order to verify the model and the computer program, an example of a ball bearing is analyzed in detail. It shows that the model and the program are reliable and the results are consistent with the data supplied by the U.S. Air Force Aeropropulsion Laboratory.

  16. Controlling roll perturbations in fruit flies

    PubMed Central

    Beatus, Tsevi; Guckenheimer, John M.; Cohen, Itai

    2015-01-01

    Owing to aerodynamic instabilities, stable flapping flight requires ever-present fast corrective actions. Here, we investigate how flies control perturbations along their body roll angle, which is unstable and their most sensitive degree of freedom. We glue a magnet to each fly and apply a short magnetic pulse that rolls it in mid-air. Fast video shows flies correct perturbations up to 100° within 30 ± 7 ms by applying a stroke-amplitude asymmetry that is well described by a linear proportional–integral controller. For more aggressive perturbations, we show evidence for nonlinear and hierarchical control mechanisms. Flies respond to roll perturbations within 5 ms, making this correction reflex one of the fastest in the animal kingdom. PMID:25762650

  17. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    SciTech Connect

    Guo, Y.; Parker, R.

    2014-01-01

    Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

  18. Log-rolling block copolymers cylinders

    NASA Astrophysics Data System (ADS)

    Kim, So Youn; Kim, Ye Chan; Kim, Dong Hyup; Kwon, Na Kyung; Register, Richard A.

    Shear has been the most effective method to create long range order of micro- or nano- structures in soft materials. When shear is applied, soft particles or polymers tend to align along the shear direction to minimize the viscous dissipation, thus transverse (so-called ``log-rolling'') alignment is unfavored. In this study, for the first time we report the transverse alignment of cylinder-forming block copolymers. Poly(styrene-b-methyl methacrylate), PS-PMMA, can form a metastable hemicylinder structure when confined in a thin film, and this hemicylinder structure can align either along the shear direction, or transverse to the shear direction (``log-rolling''), depending on the shearing temperature. This unusual ``log-rolling'' behavior is explained by the different chain mobility of the two blocks in PS-PMMA; the rigidity of core cylinder is the critical parameter determining the direction of shear alignment.

  19. Measurements of canard-induced roll oscillations

    NASA Technical Reports Server (NTRS)

    Katz, J.; Levin, D.

    1985-01-01

    A small canard wing was installed in front of a delta wing which was mounted on a free-to-roll sting balance in a low-speed wind tunnel. The leading edge vortices, originating from the canard, enhanced self-induced roll oscillations at test conditions for which the basic delta wing would otherwise have been stable. Time-dependent roll angle, and normal and side force data recorded during these oscillations are presented along with their phase relations. It was found that the canard increased the range of angle of attack at which self-induced oscillations occurred. Also, at an angle of attack of about 46 deg asymmetric oscillations are observed.

  20. Computer-aided roll pass design in rolling of airfoil shapes

    NASA Technical Reports Server (NTRS)

    Akgerman, N.; Lahoti, G. D.; Altan, T.

    1980-01-01

    This paper describes two computer-aided design (CAD) programs developed for modeling the shape rolling process for airfoil sections. The first program, SHPROL, uses a modular upper-bound method of analysis and predicts the lateral spread, elongation, and roll torque. The second program, ROLPAS, predicts the stresses, roll separating force, the roll torque and the details of metal flow by simulating the rolling process, using the slab method of analysis. ROLPAS is an interactive program; it offers graphic display capabilities and allows the user to interact with the computer via a keyboard, CRT, and a light pen. The accuracy of the computerized models was evaluated by (a) rolling a selected airfoil shape at room temperature from 1018 steel and isothermally at high temperature from Ti-6Al-4V, and (b) comparing the experimental results with computer predictions. The comparisons indicated that the CAD systems, described here, are useful for practical engineering purposes and can be utilized in roll pass design and analysis for airfoil and similar shapes.

  1. Routh symmetry in the Chaplygin's rolling ball

    NASA Astrophysics Data System (ADS)

    Kim, Byungsoo

    2011-12-01

    The Routh integral in the symmetric Chaplygin's rolling ball has been regarded as a mysterious conservation law due to its interesting form of sqrt {I_1 I_3 + m< {I_s ,s} rangle } Ω _3 . In this paper, a new form of the Routh integral is proposed as a Noether's pairing form of a conservation law. An explicit symmetry vector for the Routh integral is proved to associate the conserved quantity with the invariance of the Lagrangian function under the rollingly constrained nonholonomic variation. Then, the form of the Routh symmetry vector is discussed for its origin as the linear combination of the configurational vectors.

  2. Roll ring assemblies for the Space Station

    NASA Technical Reports Server (NTRS)

    Batista, J.; Vise, J.; Young, K.

    1994-01-01

    Space Station Freedom requires the transmission of high power and signals through three different rotational interfaces. Roll ring technology was baselined by NASA for rotary joints to transfer up to 65.5 kW of power for 30 years at greater than 99 percent efficiency. Signal transfer requirements included MIL-STD-1553 data transmission and 4.5 MHz RS250A base and color video. A unique design for each rotary joint was developed and tested to accomplish power and signal transfer. An overview of roll ring technology is presented, followed by design requirements, hardware configuration, and test results.

  3. Hormonal Regulation of Leaf Abscission

    PubMed Central

    Jacobs, William P.

    1968-01-01

    A review is given of the progress made during the last 6 years in elucidating the nature, locus of action, and transport properties of the endogenous hormones that control leaf abscission. PMID:16657014

  4. Experiments in Whole Leaf Photosynthesis

    ERIC Educational Resources Information Center

    Stewart, J. C.; And Others

    1974-01-01

    Described is a simple experimental system, which uses radioactive carbon dioxide to study whole leaf photosynthesis under a variety of conditions. Other experiments and simple apparatus for the experiments are also described. (Author/RH)

  5. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  6. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is... 7 Agriculture 2 2014-01-01 2014-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  7. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  8. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  9. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  10. Archips xylosteana (L.) (Lepidoptera: Tortricidae), a Palearctic leaf-rolling moth, new to North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Archips xylosteana (L.), a widespread Palearctic tortricid moth, is reported from St. John’s, Newfoundland, the first confirmed records of this species in North America. Adults were collected by beating branches and foliage of a variety of ornamental trees and shrubs on the campus of Memorial Univer...

  11. Why do leaf-tying caterpillars abandon their leaf ties?

    PubMed

    Sliwinski, Michelle; Sigmon, Elisha

    2013-01-01

    Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats), but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm(2) leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently abandon their leaf

  12. 40 CFR 467.20 - Applicability; description of the rolling with emulsions subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... rolling with emulsions subcategory. 467.20 Section 467.20 Protection of Environment ENVIRONMENTAL... Rolling With Emulsions Subcategory § 467.20 Applicability; description of the rolling with emulsions... the rolling with emulsions subcategory....

  13. 40 CFR 467.20 - Applicability; description of the rolling with emulsions subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... rolling with emulsions subcategory. 467.20 Section 467.20 Protection of Environment ENVIRONMENTAL... Rolling With Emulsions Subcategory § 467.20 Applicability; description of the rolling with emulsions... the rolling with emulsions subcategory....

  14. Cross-directional interlocking of rolls in an air press of a papermaking machine

    DOEpatents

    Beck, David A.; Gorshe, Thomas

    2003-05-13

    An air press for pressing a paper web is composed of a plurality of rolls including at least a first roll and a second roll. The first roll and the second roll are positioned adjacent one another and form a first nip therebetween. Further, the first roll and the second roll each have a roll end, the roll end of the first roll adjoining the roll end of the second roll. A bevel plate is attached to the roll end of the first roll, the bevel plate having at least a first angled plate face. A seal ring is positioned adjacent the roll end of the second roll, the seal ring being juxtaposed to the bevel plate. The seal ring has at least a first angled ring face, and the first angled ring face mates with the first angled plate face.

  15. What determines a leaf's shape?

    PubMed

    Dkhar, Jeremy; Pareek, Ashwani

    2014-01-01

    The independent origin and evolution of leaves as small, simple microphylls or larger, more complex megaphylls in plants has shaped and influenced the natural composition of the environment. Significant contributions have come from megaphyllous leaves, characterized usually as flat, thin lamina entrenched with photosynthetic organelles and stomata, which serve as the basis of primary productivity. During the course of evolution, the megaphylls have attained complexity not only in size or venation patterns but also in shape. This has fascinated scientists worldwide, and research has progressed tremendously in understanding the concept of leaf shape determination. Here, we review these studies and discuss the various factors that contributed towards shaping the leaf; initiated as a small bulge on the periphery of the shoot apical meristem (SAM) followed by asymmetric outgrowth, expansion and maturation until final shape is achieved. We found that the underlying factors governing these processes are inherently genetic: PIN1 and KNOX1 are indicators of leaf initiation, HD-ZIPIII, KANADI, and YABBY specify leaf outgrowth while ANGUSTIFOLIA3 and GROWTH-REGULATING FACTOR5 control leaf expansion and maturation; besides, recent research has identified new players such as APUM23, known to specify leaf polarity. In addition to genetic control, environmental factors also play an important role during the final adjustment of leaf shape. This immense amount of information available will serve as the basis for studying and understanding innovative leaf morphologies viz. the pitchers of the carnivorous plant Nepenthes which have evolved to provide additional support to the plant survival in its nutrient-deficient habitat. In hindsight, formation of the pitcher tube in Nepenthes might involve the recruitment of similar genetic mechanisms that occur during sympetaly in Petunia. PMID:25584185

  16. What determines a leaf's shape?

    PubMed

    Dkhar, Jeremy; Pareek, Ashwani

    2014-01-01

    The independent origin and evolution of leaves as small, simple microphylls or larger, more complex megaphylls in plants has shaped and influenced the natural composition of the environment. Significant contributions have come from megaphyllous leaves, characterized usually as flat, thin lamina entrenched with photosynthetic organelles and stomata, which serve as the basis of primary productivity. During the course of evolution, the megaphylls have attained complexity not only in size or venation patterns but also in shape. This has fascinated scientists worldwide, and research has progressed tremendously in understanding the concept of leaf shape determination. Here, we review these studies and discuss the various factors that contributed towards shaping the leaf; initiated as a small bulge on the periphery of the shoot apical meristem (SAM) followed by asymmetric outgrowth, expansion and maturation until final shape is achieved. We found that the underlying factors governing these processes are inherently genetic: PIN1 and KNOX1 are indicators of leaf initiation, HD-ZIPIII, KANADI, and YABBY specify leaf outgrowth while ANGUSTIFOLIA3 and GROWTH-REGULATING FACTOR5 control leaf expansion and maturation; besides, recent research has identified new players such as APUM23, known to specify leaf polarity. In addition to genetic control, environmental factors also play an important role during the final adjustment of leaf shape. This immense amount of information available will serve as the basis for studying and understanding innovative leaf morphologies viz. the pitchers of the carnivorous plant Nepenthes which have evolved to provide additional support to the plant survival in its nutrient-deficient habitat. In hindsight, formation of the pitcher tube in Nepenthes might involve the recruitment of similar genetic mechanisms that occur during sympetaly in Petunia.

  17. 2. AERIAL VIEW OF ROLLING LIFT BRIDGE. DORCHESTER AVENUE IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. AERIAL VIEW OF ROLLING LIFT BRIDGE. DORCHESTER AVENUE IN BACKGROUND. SOUTH STATION VISIBLE AT TOP LEFT. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  18. 25 CFR 75.4 - Basic membership roll.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.4 Basic membership roll. All persons whose names appear on the roll of the Eastern Band of Cherokee Indians of North Carolina, prepared...

  19. 25 CFR 75.4 - Basic membership roll.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.4 Basic membership roll. All persons whose names appear on the roll of the Eastern Band of Cherokee Indians of North Carolina, prepared...

  20. T Strip Properties Fabricated by Powder Rolling Method

    NASA Astrophysics Data System (ADS)

    Hong, Jae-Keun; Lee, Chae-Hun; Kim, Jeoung-Han; Yeom, Jong-Taek; Park, Nho-Kwang

    In the present study, the characteristics of the Ti powders fabricated by Hydride-Dehydride (HDH) were analyzed in terms of particle shape, size and size distribution. Ti powders were subjected to roll compaction and their microstructure and green densities were evaluated in terms of particle size, powder morphology, roll gap and rolling speed. Effects of blending elements having different powder sizes on densification properties were analyzed. The strip thickness was proportional to the roll gap up to 0.9 mm and the density of titanium strip was decreased with the increase in roll gap. As the roll speed increased, the strip density and thickness were decreased by using -200 mesh Ti powder. However, the effect of rolling speed for -400 mesh Ti powder was not greater than that of -200 mesh powder. The highest density by 93% was achieved by using -400 mesh Ti powder at 0.1 mm roll gap, however edge cracks and alligator cracks were occurred.

  1. Detail from roadbed showing sprocket teeth in rolling segment and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail from roadbed showing sprocket teeth in rolling segment and typical lateral bracing. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  2. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

    PubMed

    Simonin, Kevin A; Burns, Emily; Choat, Brendan; Barbour, Margaret M; Dawson, Todd E; Franks, Peter J

    2015-03-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO₂ concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO₂ concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO₂ on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO₂ assimilation rate over the diurnal course of evaporative demand.

  3. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf

    PubMed Central

    Simonin, Kevin A.; Burns, Emily; Choat, Brendan; Barbour, Margaret M.; Dawson, Todd E.; Franks, Peter J.

    2015-01-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem–leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO2 concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO2 concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO2 on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem–leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO2 assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  4. Resistance to Monopartite Begomoviruses Associated with the Bean Leaf Crumple Disease in Phaseolus vulgaris Controlled by a Single Dominant Gene.

    PubMed

    Monci, Francisco; García-Andrés, Susana; Maldonado, José Antonio; Moriones, Enrique

    2005-07-01

    ABSTRACT Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Málaga virus are monopartite begomoviruses (genus Begomovirus, family Geminiviridae) that infect common bean (Phaseolus vulgaris), causing bean leaf crumple disease (BLCD). This disease was found to be widespread in southern Spain and causes stunted growth, flower abortion, and leaf and pod deformation in common bean plants. Commercial yield losses of up to 100% occur. In the present study, we have identified and characterized a resistance trait to BLCD-associated viruses in the common bean breeding line GG12. This resistance resulted in a complete absence of BLCD symptoms under field conditions or after experimental inoculation. Our analysis showed that virus replication was not inhibited. However, a severe restriction to systemic virus accumulation occurred in resistant plants, suggesting that cell-to-cell or long-distance movement were impaired. In addition, recovery from virus infection was observed in resistant plants. The reaction of P. vulgaris lines GG12 (resistant) and GG14 (susceptible), and of F(1), F(2), and backcross populations derived from them, to TYLCV inoculation suggested that a single dominant gene conferred the BLCD resistance described here. PMID:18943015

  5. Inventing Viruses.

    PubMed

    Summers, William C

    2014-11-01

    In the nineteenth century, "virus" commonly meant an agent (usually unknown) that caused disease in inoculation experiments. By the 1890s, however, some disease-causing agents were found to pass through filters that retained the common bacteria. Such an agent was called "filterable virus," the best known being the virus that caused tobacco mosaic disease. By the 1920s there were many examples of filterable viruses, but no clear understanding of their nature. However, by the 1930s, the term "filterable virus" was being abandoned in favor of simply "virus," meaning an agent other than bacteria. Visualization of viruses by the electron microscope in the late 1930s finally settled their particulate nature. This article describes the ever-changing concept of "virus" and how virologists talked about viruses. These changes reflected their invention and reinvention of the concept of a virus as it was revised in light of new knowledge, new scientific values and interests, and new hegemonic technologies.

  6. Inventing Viruses.

    PubMed

    Summers, William C

    2014-11-01

    In the nineteenth century, "virus" commonly meant an agent (usually unknown) that caused disease in inoculation experiments. By the 1890s, however, some disease-causing agents were found to pass through filters that retained the common bacteria. Such an agent was called "filterable virus," the best known being the virus that caused tobacco mosaic disease. By the 1920s there were many examples of filterable viruses, but no clear understanding of their nature. However, by the 1930s, the term "filterable virus" was being abandoned in favor of simply "virus," meaning an agent other than bacteria. Visualization of viruses by the electron microscope in the late 1930s finally settled their particulate nature. This article describes the ever-changing concept of "virus" and how virologists talked about viruses. These changes reflected their invention and reinvention of the concept of a virus as it was revised in light of new knowledge, new scientific values and interests, and new hegemonic technologies. PMID:26958713

  7. Leaf exsertion, leaf elongation, and leaf senescence in Eriophorum vaginatum and Carex Bigelowii

    SciTech Connect

    Shaver, G.R.; Yandow, T.; Laundre, J.

    1990-01-01

    Most of the common sedges of arctic vegetation show a pattern of leaf production in which the exsertion and elongation of new leaves is more or less simultaneous with the senescence of old leaves. The present study was designed to increase our understanding of the variability sequential leaf production by arctic sedges, and to determine some of the controls on that variability. We did this in two ways: first, we compared the sequential patterns of leaf growth and senescence in E. vaginatum with those of Carex Bigelowii Torr. at two tussock tundra sites near Toolik Lake on the North Slope of Alaska. Second, we compared the responses of leaf growth in these species in control and fertilized plots and in two microenvironments thought to differ sharply in nutrient availability and total productivity. 29 refs., 28 figs., 2 tabs.

  8. 46 CFR 28.575 - Severe wind and roll.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Severe wind and roll. 28.575 Section 28.575 Shipping... INDUSTRY VESSELS Stability § 28.575 Severe wind and roll. (a) Each vessel must meet paragraphs (f) and (g) of this section when subjected to the gust wind heeling arm and the angle of roll to windward...

  9. 46 CFR 28.575 - Severe wind and roll.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Severe wind and roll. 28.575 Section 28.575 Shipping... INDUSTRY VESSELS Stability § 28.575 Severe wind and roll. (a) Each vessel must meet paragraphs (f) and (g) of this section when subjected to the gust wind heeling arm and the angle of roll to windward...

  10. 46 CFR 28.575 - Severe wind and roll.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Severe wind and roll. 28.575 Section 28.575 Shipping... INDUSTRY VESSELS Stability § 28.575 Severe wind and roll. (a) Each vessel must meet paragraphs (f) and (g) of this section when subjected to the gust wind heeling arm and the angle of roll to windward...

  11. 46 CFR 56.30-15 - Expanded or rolled joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Expanded or rolled joints. 56.30-15 Section 56.30-15... APPURTENANCES Selection and Limitations of Piping Joints § 56.30-15 Expanded or rolled joints. (a) Expanded or rolled joints may be used where experience or test has demonstrated that the joint is suitable for...

  12. 46 CFR 56.30-15 - Expanded or rolled joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Expanded or rolled joints. 56.30-15 Section 56.30-15... APPURTENANCES Selection and Limitations of Piping Joints § 56.30-15 Expanded or rolled joints. (a) Expanded or rolled joints may be used where experience or test has demonstrated that the joint is suitable for...

  13. 46 CFR 56.30-15 - Expanded or rolled joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Expanded or rolled joints. 56.30-15 Section 56.30-15... APPURTENANCES Selection and Limitations of Piping Joints § 56.30-15 Expanded or rolled joints. (a) Expanded or rolled joints may be used where experience or test has demonstrated that the joint is suitable for...

  14. 25 CFR 75.15 - Current membership roll.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Current membership roll. 75.15 Section 75.15 Indians... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.15 Current membership roll. The membership roll of the Eastern Band of Cherokee Indians shall be kept current by striking therefrom the names...

  15. 25 CFR 75.15 - Current membership roll.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Current membership roll. 75.15 Section 75.15 Indians... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.15 Current membership roll. The membership roll of the Eastern Band of Cherokee Indians shall be kept current by striking therefrom the names...

  16. 25 CFR 75.15 - Current membership roll.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Current membership roll. 75.15 Section 75.15 Indians... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.15 Current membership roll. The membership roll of the Eastern Band of Cherokee Indians shall be kept current by striking therefrom the names...

  17. 25 CFR 75.15 - Current membership roll.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Current membership roll. 75.15 Section 75.15 Indians... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.15 Current membership roll. The membership roll of the Eastern Band of Cherokee Indians shall be kept current by striking therefrom the names...

  18. 25 CFR 75.15 - Current membership roll.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Current membership roll. 75.15 Section 75.15 Indians... THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.15 Current membership roll. The membership roll of the Eastern Band of Cherokee Indians shall be kept current by striking therefrom the names...

  19. 25 CFR 75.4 - Basic membership roll.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Basic membership roll. 75.4 Section 75.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT REVISION OF THE MEMBERSHIP ROLL OF THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.4 Basic membership roll. All persons...

  20. 21 CFR 136.130 - Milk bread, rolls, and buns.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Milk bread, rolls, and buns. 136.130 Section 136....130 Milk bread, rolls, and buns. (a) Each of the foods milk bread, milk rolls, and milk buns conforms... permitted in the preparation of the dough is milk or, as an alternative, a combination of dairy products...