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Sample records for verticillium wilt electronic

  1. Association mapping of resistance to Verticillium wilt in Gossypium ...

    African Journals Online (AJOL)

    Verticillium wilt is a major disease affecting the growth of cotton. For screening the resistant genes, 320 Gossypium hirsutum germplasms were evaluated in Verticillium nursery, and association mapping was used to detect the markers associated with the Verticillium wilt resistance. 106 microsatellite marker primer pairs ...

  2. Biological control agent against verticillium wilt

    CSIR Research Space (South Africa)

    Gumede, WHN

    2006-04-01

    Full Text Available Verticillium wilt Presented at the 14th Biennial congress of the South African Society for Microbiology WHN Gumede CSIR Biosciences 11-04-06 Slide 2 © CSIR 2006 www.csir.co.za INTRODUCTION • Historical background • Application...

  3. A Review of Control Options and Externalities for Verticillium Wilts.

    Science.gov (United States)

    Carroll, Christine L; Carter, Colin A; Goodhue, Rachael E; Lawell, C-Y Cynthia Lin; Subbarao, Krishna V

    2018-02-01

    Plant pathogens migrate to new regions through human activities such as trade, where they may establish themselves and cause disease on agriculturally important crops. Verticillium wilt of lettuce, caused by Verticillium dahliae, is a soilborne fungus that was introduced to coastal California via infested spinach seeds. It has caused significant losses for lettuce growers. Once introduced, Verticillium wilt could be managed by fumigating with methyl bromide and chloropicrin, but this option is no longer available. Growers can also manage the disease by planting broccoli or not planting spinach. These control options require long-term investments for future gain. Verticillium wilt can also be prevented or controlled by testing and providing spinach seeds with little or no V. dahliae infestation. However, seed companies have been reluctant to test or clean spinach seeds, as spinach crops are not affected by Verticillium wilt. Thus, available control options are affected by externalities. Renters and other producers with short time horizons will not undertake long-term investments and seed companies do not take into account the effect of their decision not to test on lettuce producers. We review the literature on the economics of managing crop disease; discuss the economics of managing Verticillium wilt; and review the recent research on the externalities that arise with short-term growers, and between seed companies and growers due to Verticillium wilt. An externality arises whenever the actions of one individual or firm affects the payoffs to another individual or firm not involved in a specific transaction. These externalities have important implications for the management of Verticillium wilt and, more broadly, for the management of migratory pathogens and the diseases they cause in agriculture in general. This review is of interest to policy-makers, the producers, marketers, seed companies, and researchers.

  4. SNP association analysis of resistance to Verticillium wilt (Verticillium dahliae Kleb.) in spinach

    Science.gov (United States)

    Verticillium wilt, caused by Verticillium dahliae Kleb. is one of important fungus diseases in spinach (Spinacia oleracea L.) and the most economical method of control this disease is through the use of genetic resistance, especially for organic growers. The objective of this research is to evaluate...

  5. Insertional mutagenesis in the vascular wilt pathogen Verticillium dahliae

    NARCIS (Netherlands)

    Santhanam, P.

    2014-01-01

    Vascular wilt diseases caused by soil-borne pathogens are among the most devastating plant diseases worldwide. The ascomycete fungus Verticillium dahliae causes vascular wilt diseases in hundreds of dicotyledonous plant species, including important crops such as eggplant, lettuce, olive, spinach

  6. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt.

    Science.gov (United States)

    Deketelaere, Silke; Tyvaert, Lien; França, Soraya C; Höfte, Monica

    2017-01-01

    The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA) against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae , and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta . Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1) affect the survival or germination of microsclerotia, (2) colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3) induce resistance responses in the plant and/or (4) promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods should be

  7. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt

    Directory of Open Access Journals (Sweden)

    Silke Deketelaere

    2017-07-01

    Full Text Available The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae, and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta. Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1 affect the survival or germination of microsclerotia, (2 colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3 induce resistance responses in the plant and/or (4 promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods

  8. Molecular research and genetic engineering of resistance to Verticillium wilt in cotton: A review

    Science.gov (United States)

    Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing the crop’s production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became e...

  9. Verticillium wilt in nursery trees: damage thresholds, spatial and temporal aspects

    NARCIS (Netherlands)

    Goud, J.C.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2011-01-01

    Verticillium wilt can cause high losses in tree nurseries. To be able to predict disease and unravel disease dynamics over time and space, the relationship between verticillium wilt and soil inoculum densities of Verticillium dahliae and the nematode Pratylenchus fallax was studied in two 4-year

  10. Effect of solarization with fresh chicken manure on verticillium wilt ...

    African Journals Online (AJOL)

    The present study was carried out to evaluate the effect of reducing wilt disease through the medium of fresh chicken manure (FCM) mixed with soil before solarized and then artificial Verticillium dahliae (V.d) inoculation on yield of eggplant (Solanum melongena L.) under field conditions. According to the splitplot design, ...

  11. Comparative RNA-seq for the investigation of tolerance to Verticillium wilt in black raspberry

    Science.gov (United States)

    Verticillium dahliae Kleb., a cause of verticillium wilt, is a wide-spread, soil-borne fungal pathogen with a wide host range that includes many fruit and vegetable crops. Verticillium dahliae has been isolated from Rubus species showing symptoms of the disease. Very little is known about the intera...

  12. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease

    OpenAIRE

    Yuan, Yuan; Feng, Hongjie; Wang, Lingfei; Li, Zhifang; Shi, Yongqiang; Zhao, LiHong; Feng, Zili; Zhu, Heqin

    2017-01-01

    Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum), CEF-714 (Leptosphaeria sp.), CEF-642 (Talaromyces flavus.) and CEF-193 (Acremonium sp.) isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease in...

  13. The economics of managing Verticillium wilt, an imported disease in California lettuce

    Directory of Open Access Journals (Sweden)

    Christine L. Carroll

    2017-09-01

    Full Text Available Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take the steps needed to control Verticillium wilt. Verticillium wilt can also be prevented or controlled by a spinach seed company through testing and cleaning the spinach seeds. However, seed companies are unwilling to test or clean spinach seeds, as they are not affected by this disease. We discuss our research on the externalities that arise with renters, and between seed companies and growers, due to Verticillium wilt. These externalities have important implications for the management of Verticillium wilt in particular, and for the management of diseases in agriculture in general.

  14. A model for multiseasonal spread of verticillium wilt of lettuce.

    Science.gov (United States)

    Wu, B M; Subbarao, K V

    2014-09-01

    Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

  15. Breeding and genetics of lettuce for resistance against race 2 Verticillium wilt

    Science.gov (United States)

    Verticillium wilt, caused by Verticillium dahliae Kleb., is an economically important disease of lettuce in central coastal California. Most isolates of the pathogen detected in the Salinas Valley belong to race 1 for which complete resistance exists. However, adequate level of resistance is not ava...

  16. Temporal patterns of cotton Fusarium and Verticillium wilt in Jiangsu coastal areas of China.

    Science.gov (United States)

    Li, Xiaogang; Zhang, Ya'nan; Ding, Changfeng; Xu, Wenhua; Wang, Xingxiang

    2017-10-03

    Cotton diseases caused by soil-borne pathogenic fungi present a major constraint to cotton production not only in China but also worldwide. A long-term field inventory was made of the prevalence of Fusarium and Verticillium wilt of cotton in the Jiangsu coastal area of China from 2000 to 2014. Various factors (crop varieties, rotation and weather) were analyzed to explore the dynamics of these diseases in cotton. The results showed that the prevalence of Fusarium and Verticillium wilt increased before 2005 and that Verticillium wilt remained at a high incidence over most of the past 10 years, while Fusarium wilt began to gradually decrease after 2005. The dynamics of Fusarium and Verticillium wilt were closely associated with the introduced cotton varieties and the intensive cropping history. In addition, weather conditions occurring during some of the years appeared to coincide with a substantial variation in the wilt diseases. Our study highlighted epidemiological dynamics of Fusarium and Verticillium wilt in a long-term survey.

  17. Cotton GhBAK1 mediates Verticillium wilt resistance and cell death.

    Science.gov (United States)

    Gao, Xiquan; Li, Fangjun; Li, Maoying; Kianinejad, Ali S; Dever, Jane K; Wheeler, Terry A; Li, Zhaohu; He, Ping; Shan, Libo

    2013-07-01

    Virus-induced gene silencing (VIGS) offers a powerful approach for functional analysis of individual genes by knocking down their expression. We have adopted this approach to dissect gene functions in cotton resistant to Verticillium wilt, one of the most devastating diseases worldwide. We showed here that highly efficient VIGS was obtained in a cotton breeding line (CA4002) with partial resistance to Verticillium wilt, and GhMKK2 and GhVe1 are required for its resistance to Verticillium wilt. Arabidopsis AtBAK1/SERK3, a central regulator in plant disease resistance, belongs to a subfamily of somatic embryogenesis receptor kinases (SERKs) with five members, AtSERK1 to AtSERK5. Two BAK1 orthologs and one SERK1 ortholog were identified in the cotton genome. Importantly, GhBAK1 is required for CA4002 resistance to Verticillium wilt. Surprisingly, silencing of GhBAK1 is sufficient to trigger cell death accompanied with production of reactive oxygen species in cotton. This result is distinct from Arabidopsis in which AtBAK1 and AtSERK4 play redundant functions in cell death control. Apparently, cotton has only evolved SERK1 and BAK1 whereas AtSERK4/5 are newly evolved genes in Arabidopsis. Our studies indicate the functional importance of BAK1 in Verticillium wilt resistance and suggest the dynamic evolution of SERK family members in different plant species. © 2013 Institute of Botany, Chinese Academy of Sciences.

  18. Selection for resistance to Verticillium wilt caused by race 2 isolates of Verticillium dahliae in accessions of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. The pathogen exists as two races (races 1 and 2) in lettuce, and complete resistance to race 1 is known. Resistance to race 2 isolates has not been reported, and production of race 1 re...

  19. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L. using high-resolution melting.

    Directory of Open Access Journals (Sweden)

    Tiejun Zhang

    Full Text Available Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L. worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR and single nucleotide polymorphism (SNP markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  20. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L.) using high-resolution melting.

    Science.gov (United States)

    Zhang, Tiejun; Yu, Long-Xi; McCord, Per; Miller, David; Bhamidimarri, Suresh; Johnson, David; Monteros, Maria J; Ho, Julie; Reisen, Peter; Samac, Deborah A

    2014-01-01

    Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L.) worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  1. Biocontrol potential of Trichoderma harzianum in controlling wilt disease of pistachio caused by Verticillium dahliae

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    Fotoohiyan Zeinab

    2017-06-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae, is one of the most devastating diseases in pistachio orchards in the world including Iran. In search for an effective non-chemical strategy for the management of this disease, we evaluated the biocontrol potential of Trichoderma harzianum isolates obtained from the rhizosphere of healthy pistachio trees in different locations of the Kerman province of Iran against V. dahliae under laboratory and greenhouse conditions. Dual culture tests in the laboratory were conducted in a completely randomized design using 72 T. harzianum isolates. Twenty isolates showed the highest in vitro antagonistic activity. The results indicated that all 20 isolates were capable of inhibiting the mycelial growth of V. dahliae significantly. Among them, isolates Tr8 and Tr19 were the most effective by 88.89% and 85.12% inhibition, respectively. Extracted cell free metabolites of all effective isolates also inhibited the growth of V. dahliae in the culture medium significantly. According to the results, isolates Tr4 and Tr6 inhibited fungal pathogen growth by 94.94% and 88.15% respectively, through production of non-volatile metabolites. In the evaluation of volatile metabolites, isolates Tr5 and Tr4 were the most effective by 26.27% and 24.49% growth inhibition, respectively. Based on the results of the in vitro experiments, the five most effective isolates were selected for evaluation under greenhouse conditions for their biocontrol potential in controlling Verticillium wilt of pistachio. Results of the greenhouse, (in vivo experiments were positive and indicated that the occurrence of wilt disease in plants treated with the antagonists alone or in combination with pathogenic fungus was lower than in plants inoculated with pathogen alone. The overall results of this study suggest that Trichoderma fungal antagonist may be an effective biocontrol agent for the control of Verticillium wilt of pistachio.

  2. Overexpression of 3-deoxy-7-phosphoheptulonate synthase gene from Gossypium hirsutum enhances Arabidopsis resistance to Verticillium wilt.

    Science.gov (United States)

    Yang, Jun; Ji, Lianlian; Wang, Xingfen; Zhang, Yan; Wu, Lizhu; Yang, Yingna; Ma, Zhiying

    2015-08-01

    Expression of DHS1 in cotton is induced upon infection by Verticillium dahliae , and overexpression of GhDHS1 endows transgenic Arabidopsis plants excellent Verticillium resistance. Verticillium wilt is caused by a soil-borne fungus Verticillium dahliae. Resistance in most cotton cultivars is either scarce or unavailable, making Verticillium wilt a major obstacle in cotton production. Here, we identified a 3-deoxy-7-phosphoheptulonate synthase (DHS, EC 4.1.2.15) gene from Gossypium hirsutum, named GhDHS1. Its 1620 bp open reading frame encodes a putative 59.4 kDa protein. Phylogenetic analysis indicated that GhDHS1 is clustered in a clade with potato and tomato DHSs that can be induced by wounding and elicitors, respectively. Expression analysis demonstrated that GhDHS1 is constitutively expressed in cotton roots and stems, but transcripts are rare or non-existent in the leaves. Subcellular localization showed that GhDHS1 occurs in the plastids. When plants of three cultivars were inoculated with V. dahliae, DHS1 expression was more significantly up-regulated in the roots of resistant G. barbadense cv. Pima90-53 and G. hirsutum cv. Jimian20 than in the susceptible G. hirsutum cv. Han208. This suggested that DHS1 is involved in the cotton resistance to Verticillium wilt. Furthermore, GhDHS1 overexpressing transgenic lines of Arabidopsis were developed via Agrobacterium tumefaciens-mediated transformation. Compared with the untransformed WT (wild type), these transgenic plants showed excellent Verticillium wilt resistance with a significantly lower disease index. The overexpressing transgenic lines also had significantly longer primary roots and greatly increased xylem areas under V. dahliae infection. Overall, our results indicate that GhDHS1 performs a role in the cotton resistance to V. dahliae and would be potential to breeding cottons of Verticillium wilt resistance.

  3. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease.

    Science.gov (United States)

    Yuan, Yuan; Feng, Hongjie; Wang, Lingfei; Li, Zhifang; Shi, Yongqiang; Zhao, LiHong; Feng, Zili; Zhu, Heqin

    2017-01-01

    Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum), CEF-714 (Leptosphaeria sp.), CEF-642 (Talaromyces flavus.) and CEF-193 (Acremonium sp.) isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease incidence and disease index, with the control efficacy ranging from 26% (CEF-642) to 67% (CEF-818) at 25 days (d) after inoculation. In the disease nursery, compared to controls (with disease incidence of 33.8% and disease index of 31), CEF-818, CEF-193, CEF-714 and CEF-642 provided a protection effect of 69.5%, 69.2%, 54.6% and 45.7%, respectively. Especially, CEF-818 and CEF-714 still provided well protection against Verticillium wilt with 46.9% and 56.6% or 14.3% and 33.7% at the first peak of the disease in heavily infected field, respectively (in early July). These results indicated that these endophytes not only delayed but also reduced wilt symptoms on cotton. In the harvest, the available cotton bolls of plant treated with CEF-818 and CEF-714 increased to 13.1, and 12.2, respectively. And the seed cotton yield significantly increased after seed bacterization with CEF-818 (3442.04 kg/ha) compared to untreated control (3207.51 kg/ha) by 7.3%. Furtherly, CEF-818 and CET-714 treatment increased transcript levels for PAL, PPO, POD, which leads to the increase of cotton defense reactions. Our results indicate that seed treatment of cotton plants with CEF-818 and CET-714 can help in the biocontrol of V. dahliae and improve seed cotton yield in cotton fields. This study provided a better understanding of cotton-endophyte interactions which will aid in developing effective biocontrol agents for Verticillium wilt of cotton in futhre.

  4. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease.

    Directory of Open Access Journals (Sweden)

    Yuan Yuan

    Full Text Available Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum, CEF-714 (Leptosphaeria sp., CEF-642 (Talaromyces flavus. and CEF-193 (Acremonium sp. isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease incidence and disease index, with the control efficacy ranging from 26% (CEF-642 to 67% (CEF-818 at 25 days (d after inoculation. In the disease nursery, compared to controls (with disease incidence of 33.8% and disease index of 31, CEF-818, CEF-193, CEF-714 and CEF-642 provided a protection effect of 69.5%, 69.2%, 54.6% and 45.7%, respectively. Especially, CEF-818 and CEF-714 still provided well protection against Verticillium wilt with 46.9% and 56.6% or 14.3% and 33.7% at the first peak of the disease in heavily infected field, respectively (in early July. These results indicated that these endophytes not only delayed but also reduced wilt symptoms on cotton. In the harvest, the available cotton bolls of plant treated with CEF-818 and CEF-714 increased to 13.1, and 12.2, respectively. And the seed cotton yield significantly increased after seed bacterization with CEF-818 (3442.04 kg/ha compared to untreated control (3207.51 kg/ha by 7.3%. Furtherly, CEF-818 and CET-714 treatment increased transcript levels for PAL, PPO, POD, which leads to the increase of cotton defense reactions. Our results indicate that seed treatment of cotton plants with CEF-818 and CET-714 can help in the biocontrol of V. dahliae and improve seed cotton yield in cotton fields. This study provided a better understanding of cotton-endophyte interactions which will aid in developing effective biocontrol agents for Verticillium wilt of cotton in futhre.

  5. Successful strategy for the selection of new strawberry-associated rhizobacteria antagonistic to Verticillium wilt.

    Science.gov (United States)

    Berg, G; Kurze, S; Buchner, A; Wellington, E M; Smalla, K

    2000-12-01

    In order to isolate and characterize new strawberry-associated bacteria antagonistic to the soil-borne pathogenic fungus Verticillium dahliae Kleb., rhizobacterial populations from two different strawberry species, Greenish Strawberry (Fragaria viridis) and Garden Strawberry (F. x ananassa) obtained after plating onto King's B and glycerol-arginine agar, were screened for in vitro antagonism toward V. dahliae. The proportion of isolates with antifungal activity determined in in vitro assay against V. dahliae was higher for the Garden Strawberry than for the Greenish Strawberry. From 300 isolates, 20 isolates with strong antifungal activity were selected characterized by physiological profiling and molecular fingerprinting methods. Diversity among the isolates was characterized with molecular fingerprints using amplified ribosomal DNA restriction analysis (ARDRA) and the more discriminating BOX-PCR fingerprint method. The physiological profiles were well correlated with molecular fingerprinting pattern analysis. Significant reduction of Verticillium wilt by bacterial dipping bath treatment was shown in the greenhouse and in fields naturally infested by V. dahliae. The relative increase of yield ranged from 117% (Streptomyces albidoflavus S1) to 344% (Pseudomonas fluorescens P10) in greenhouse trials, and 113% (Streptomyces albidoflavus S1) to 247% (Pseudomonas fluorescens P6) in field trials. Evaluation resulted in the selection of three effective biocontrol agents (Pseudomonas fluorescens P6, P10, and Streptomyces diastatochromogenes S9) antagonistic to the Verticillium wilt pathogen.

  6. Management of Verticillium wilt of potato with disease-suppressive green manures and as affected by previous cropping history

    Science.gov (United States)

    The ability of potential disease-suppressive rotation crops to reduce potato disease problems and increase crop productivity in a field severely infested with Verticillium wilt was evaluated over three field seasons in Maine. Disease-suppressive rotation treatments consisted of 1) a high glucosinola...

  7. Efficacy of Seaweed Concentrate from Ecklonia maxima (Osbeck and Conventional Fungicides in the Control of Verticillium Wilt of Pepper

    Directory of Open Access Journals (Sweden)

    Emil Rekanović

    2010-01-01

    Full Text Available In order to control the causal agent of Verticillium wilt of pepper (Verticillium dahliae,the efficacy of two conventional fungicides, thiophanate-methyl and carbendazim,and seaweed concentrate (SWC from Ecklonia maxima was evaluated in greenhouse conditions. Pepper plants were inoculated with selected V. dahliae isolate in the stage of more than nine fully developed leaves on primary stem. The tested fungicides and SWC were applied three days before inoculation of pepper plants. Carbendazim was the most efficient fungicide among tested substances (69.64%. SWC proved to be more effective when applied at 1.0% concentarion (41.96%. The use of thiophanate-methyl provided good Verticillium wilt control in pepper (60.71%. SWC was less efficient than thiophanate-methyl and carbendazim, but still significantly better compared to the disease control plot.

  8. Spatial Pattern of Verticillium dahliae Microsclerotia and Cotton Plants with Wilt Symptoms in Commercial Plantations.

    Directory of Open Access Journals (Sweden)

    Feng Wei

    Full Text Available Spatial patterns of pathogen inoculum in field soils and the resulting patterns of disease may reflect the underlying mechanisms of pathogen dispersal. This knowledge can be used to design more efficient sampling schemes for assessing diseases. Spatial patterns of Verticillium dahliae microsclerotia were characterized in commercial cotton fields through quadrat and point sampling in 1994 and 2013, respectively. Furthermore, cotton plants with wilt symptoms, caused by V. dahliae, were assessed in six commercial cotton fields in 2013. Soil samples were assayed for the density of microsclerotia (expressed as CFU g-1 of soil using a wet-sieving plating method and a real-time quantitative PCR method for the 1994 and 2013 study, respectively. The estimated inoculum threshold for causing wilt development on individual plants varied with the three fields: ca. 1.6 CFU g-1 of soil for one field, and 7.2 CFU g-1 of soil for the other two. Both quadrat and point sampling spatial analyses showed that aggregation of V. dahliae inoculum in soils was usually not detected beyond 1.0 m. Similarly, the spatial patterns of wilted cotton plants indicated that spatial aggregation of diseased plants were only observed below the scale of 1.0 m in six commercial cotton plantations. Therefore, spatial aggregation of both V. dahliae inoculum and cotton plants with wilt symptoms is not likely to be detected above the scale of 1.0 m for most commercial cotton plantations. When designing schemes for assessing wilt inoculum and wilt development, this scale needs to be taken into consideration.

  9. Biocontrol of verticillium wilt and colonization of cotton plants by an endophytic bacterial isolate.

    Science.gov (United States)

    Li, C-H; Shi, L; Han, Q; Hu, H-L; Zhao, M-W; Tang, C-M; Li, S-P

    2012-09-01

    To explore biocontrol potential of 39 DAEB isolates (doubly antagonistic towards both Verticillium dahliae Kleb and Fusarium oxysporum) against verticillium wilt of cotton and to elucidate colonization and category characteristics of an endophytic bacterium with significant biocontrol activity. Thirty-nine antagonistic endophytic bacteria strains were tested for their ability to control verticillium wilt in cotton plants caused by a defoliating pathotype of V. dahliae 107 in cotton under controlled conditions. The biocontrol trial revealed that an endophytic bacterium, designated HA02, showed a significant biocontrol activity to V. dahliae 107. After cotton seedlings were inoculated with a gfp gene-tagged HA02 (HA02-gfp), HA02-gfp populations were higher in the root than in the stem; in addition, the HA02-gfp was distributed in the maturation zone of cotton root. Furthermore, HA02-gfp also colonized seedlings of maize, rape and soybean after the bacteria inoculation. Phylogenetic trees based on 16S rDNA sequences combined with morphological, physiological and identification showed that the bacterium belongs to the Enterobacter genus. Our results showed that only 1 of 39 DAEB isolates demonstrated more efficient biocontrol potential towards V. dahliae 107 in greenhouse and field trials. HA02-gfp mainly colonized cotton in roots. In addition, we quantitatively observed HA02 colonization in other hosts. HA02 belongs to the Enterobacter genus. This is the first study on biocontrol to defoliating pathotype of V. dahliae Kleb by endophytic bacteria. The HA02 showed effective biocontrol to V. dahliae 107 in greenhouse and field trials. Furthermore, we assessed the quantitative and qualitative colonization of HA02 in cotton seedlings. Our study provides basic information to further explore managing strategies to control this critical disease. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  10. The Ectopic Overexpression of the Cotton Ve1 and Ve2-Homolog Sequences Leads to Resistance Response to Verticillium Wilt in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jieyin Chen

    2017-05-01

    Full Text Available Verticillium wilt, caused by the Verticillium dahliae phytopathogen, is a devastating disease affecting many economically important crops. A receptor-like protein (RLP gene, Ve1, has been reported to confer resistance to V. dahliae in tomato plants, but few genes have been found to be involved in cotton Verticillium wilt resistance. Here, we cloned two RLP gene homologs, Gossypium barbadense resistance gene to Verticillium dahliae 1 (GbaVd1 and GbaVd2, from the Verticillium wilt-resistant cultivar G. barbadense cv. Hai7124. GbaVd1 and GbaVd2 display sequence divergence, but both encode typical RLPs. Virus-induced gene silencing of GbaVd1 or GbaVd2 compromised the resistance of cotton to V. dahliae, and both genes conferred Verticillium wilt resistance after interfamily transfer into Arabidopsis. Microarray analysis revealed that GbaVd1 and GbaVd2 participate in Verticillium wilt resistance in Arabidopsis through activation of defense responses, including the endocytosis process, signaling factors, transcription factors and reinforcement of the cell wall, as demonstrated by lignification in Arabidopsis transgenic plants. In addition, microarray analysis showed that GbaVd1 and GbaVd2 differentially mediate resistance signaling and activation of defense responses after overexpression in Arabidopsis. Thus, GbaVd1 and GbaVd2 encode RLPs and act as disease resistance genes that mediate the defense response against V. dahliae in cotton.

  11. Verticillium wilt of olive branches in Iran and its control managements with soil solarization method.

    Science.gov (United States)

    Saremi, H; Amarlou, A; Okhovvat, S M

    2006-01-01

    Wilting of mostly one branch in nurseries and newly established orchards of olive was studied in eastern north of Iran including Zanjan, Golestan and Khorassan provinces during 2002-2004. Different infected plants were visited and samples showing symptoms including wilting or death of branches collected from various areas and transferred to laboratory. Samples were cultured in common media (PDA) and different fungi were identified. The most frequently isolated pathogen was Verticillium dahliae which caused wilting of mostly one branch of olive seedling or trees in studied areas. Results showed that the disease caused main losses where olive cuttings were cultured in infected soils, previously cropped to susceptible plants. In fact, the population density of V. dahliae was high in the garden soil, previously produced susceptible crop cultivar to the fungus especially cotton or potatoes. Soil disinfestations by soil solarization method was carried in Taroam as the warmer climate in studied areas to control the pathogen. Application of this method reduced population density of the pathogen from 1700 CFU g/soil to 1000 after 4 weeks. This method was simple, effective, non negative side and economic which can be used in nearly warm areas.

  12. Constitutive expression of a novel antimicrobial protein, Hcm1, confers resistance to both Verticillium and Fusarium wilts in cotton.

    Science.gov (United States)

    Zhang, Zhiyuan; Zhao, Jun; Ding, Lingyun; Zou, Lifang; Li, Yurong; Chen, Gongyou; Zhang, Tianzhen

    2016-02-09

    Fusarium and Verticillium wilts, two of the most important diseases in cotton, pose serious threats to cotton production. Here we introduced a novel antimicrobial protein Hcm1, which comprised harpin protein from Xanthomonas oryzae pv. oryzicola (Xoc), and the chimeric protein, cecropin A-melittin, into cotton. The transgenic cotton lines with stable Hcm1 expression showed a higher resistance to Verticillium and Fusarium wilts both in greenhouse and field trials compared to controls. Hcm1 enabled the transgenic cotton to produced a microscopic hypersensitive response (micro-HR), reactive oxygen species (ROS) burst, and caused the activation of pathogenesis-related (PR) genes in response to biotic stress, indicating that the transgenic cotton was in a primed state and ready to protect the host from pathogenic infection. Simultaneously, Hcm1 protein inhibited the growth of Verticillium dahliae (V. dahliae) and Fusarium oxysporum (F. oxysporum) in vitro. The spread of fungal biomass was also inhibited in vivo since the V. dahliae biomass was decreased dramatically in transgenic cotton plants after inoculation with V. dahliae. Together, these results demonstrate that Hcm1 could activate innate immunity and inhibit the growth of V. dahliae and F. oxysporum to protect cotton against Verticillium and Fusarium wilts.

  13. Heterologous Expression of the Cotton NBS-LRR Gene GbaNA1 Enhances Verticillium Wilt Resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Nan-Yang Li

    2018-02-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae results in severe losses in cotton, and is economically the most destructive disease of this crop. Improving genetic resistance is the cleanest and least expensive option to manage Verticillium wilt. Previously, we identified the island cotton NBS-LRR-encoding gene GbaNA1 that confers resistance to the highly virulent V. dahliae isolate Vd991. In this study, we expressed cotton GbaNA1 in the heterologous system of Arabidopsis thaliana and investigated the defense response mediated by GbaNA1 following inoculations with V. dahliae. Heterologous expression of GbaNA1 conferred Verticillium wilt resistance in A. thaliana. Moreover, overexpression of GbaNA1 enabled recovery of the resistance phenotype of A. thaliana mutants that had lost the function of GbaNA1 ortholog gene. Investigations of the defense response in A. thaliana showed that the reactive oxygen species (ROS production and the expression of genes associated with the ethylene signaling pathway were enhanced significantly following overexpression of GbaNA1. Intriguingly, overexpression of the GbaNA1 ortholog from Gossypium hirsutum (GhNA1 in A. thaliana did not induce the defense response of ROS production due to the premature termination of GhNA1, which lacks the encoded NB-ARC and LRR motifs. GbaNA1 therefore confers Verticillium wilt resistance in A. thaliana by the activation of ROS production and ethylene signaling. These results demonstrate the functional conservation of the NBS-LRR-encoding GbaNA1 in a heterologous system, and the mechanism of this resistance, both of which may prove valuable in incorporating GbaNA1-mediated resistance into other plant species.

  14. Genome-wide analysis of the gene families of resistance gene analogues in cotton and their response to Verticillium wilt.

    Science.gov (United States)

    Chen, Jie-Yin; Huang, Jin-Qun; Li, Nan-Yang; Ma, Xue-Feng; Wang, Jin-Long; Liu, Chuan; Liu, Yong-Feng; Liang, Yong; Bao, Yu-Ming; Dai, Xiao-Feng

    2015-06-19

    Gossypium raimondii is a Verticillium wilt-resistant cotton species whose genome encodes numerous disease resistance genes that play important roles in the defence against pathogens. However, the characteristics of resistance gene analogues (RGAs) and Verticillium dahliae response loci (VdRLs) have not been investigated on a global scale. In this study, the characteristics of RGA genes were systematically analysed using bioinformatics-driven methods. Moreover, the potential VdRLs involved in the defence response to Verticillium wilt were identified by RNA-seq and correlations with known resistance QTLs. The G. raimondii genome encodes 1004 RGA genes, and most of these genes cluster in homology groups based on high levels of similarity. Interestingly, nearly half of the RGA genes occurred in 26 RGA-gene-rich clusters (Rgrcs). The homology analysis showed that sequence exchanges and tandem duplications frequently occurred within Rgrcs, and segmental duplications took place among the different Rgrcs. An RNA-seq analysis showed that the RGA genes play roles in cotton defence responses, forming 26 VdRLs inside in the Rgrcs after being inoculated with V. dahliae. A correlation analysis found that 12 VdRLs were adjacent to the known Verticillium wilt resistance QTLs, and that 5 were rich in NB-ARC domain-containing disease resistance genes. The cotton genome contains numerous RGA genes, and nearly half of them are located in clusters, which evolved by sequence exchanges, tandem duplications and segmental duplications. In the Rgrcs, 26 loci were induced by the V. dahliae inoculation, and 12 are in the vicinity of known Verticillium wilt resistance QTLs.

  15. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  16. Genetic structure, linkage disequilibrium and association mapping of Verticillium wilt resistance in elite cotton (Gossypium hirsutum L.) germplasm population.

    Science.gov (United States)

    Zhao, Yunlei; Wang, Hongmei; Chen, Wei; Li, Yunhai

    2014-01-01

    Understanding the population structure and linkage disequilibrium in an association panel can effectively avoid spurious associations and improve the accuracy in association mapping. In this study, one hundred and fifty eight elite cotton (Gossypium hirsutum L.) germplasm from all over the world, which were genotyped with 212 whole genome-wide marker loci and phenotyped with an disease nursery and greenhouse screening method, were assayed for population structure, linkage disequilibrium, and association mapping of Verticillium wilt resistance. A total of 480 alleles ranging from 2 to 4 per locus were identified from all collections. Model-based analysis identified two groups (G1 and G2) and seven subgroups (G1a-c, G2a-d), and differentiation analysis showed that subgroup having a single origin or pedigree was apt to differentiate with those having a mixed origin. Only 8.12% linked marker pairs showed significant LD (Presistance were identified through association mapping, which widely were distributed among 15 chromosomes. Among which 10 marker loci were found to be consistent with previously identified QTLs and 32 were new unreported marker loci, and QTL clusters for Verticillium wilt resistanc on Chr.16 were also proved in our study, which was consistent with the strong linkage in this chromosome. Our results would contribute to association mapping and supply the marker candidates for marker-assisted selection of Verticillium wilt resistance in cotton.

  17. The inheritance of resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae in the lettuce cultivar La Brillante.

    Science.gov (United States)

    Hayes, Ryan J; McHale, Leah K; Vallad, Gary E; Truco, Maria Jose; Michelmore, Richard W; Klosterman, Steve J; Maruthachalam, Karunakaran; Subbarao, Krishna V

    2011-08-01

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. Complete resistance to race 1 isolates is available in Lactuca sativa cultivar (cv.) La Brillante and understanding the genetic basis of this resistance will aid development of new resistant cultivars. F(1) and F(2) families from crosses between La Brillante and three iceberg cultivars as well as a recombinant inbred line population derived from L. sativa cv. Salinas 88 × La Brillante were evaluated for disease incidence and disease severity in replicated greenhouse and field experiments. One hundred and six molecular markers were used to generate a genetic map from Salinas 88 × La Brillante and for detection of quantitative trait loci. Segregation was consistent with a single dominant gene of major effect which we are naming Verticillium resistance 1 (Vr1). The gene described large portions of the phenotypic variance (R(2) = 0.49-0.68) and was mapped to linkage group 9 coincident with an expressed sequence tag marker (QGD8I16.yg.ab1) that has sequence similarity with the Ve gene that confers resistance to V. dahliae race 1 in tomato. The simple inheritance of resistance indicates that breeding procedures designed for single genes will be applicable for developing resistant cultivars. QGD8I16.yg.ab1 is a good candidate for functional analysis and development of markers suitable for marker-assisted selection.

  18. A fungal protein elicitor PevD1 induces Verticillium wilt resistance in cotton.

    Science.gov (United States)

    Bu, Bingwu; Qiu, Dewen; Zeng, Hongmei; Guo, Lihua; Yuan, Jingjing; Yang, Xiufen

    2014-03-01

    We found that the elicitor PevD1 triggered innate immunity in cotton, which plays an important role in future cotton wilt disease control. Elicitors can induce defense responses in plants and improve pathogen resistance. PevD1 is a secreted protein from Verticillium dahliae and activates the hypersensitive response and systemic acquired resistance to tobacco mosaic virus in tobacco plants. To investigate the PevD1-induced disease resistance mechanisms in cotton (Gossypium hirsutum), we report that Escherichia coli expressing PevD1 enhanced cotton resistance and the defense response to the fungal pathogen V. dahliae. The results showed that recombinant PevD1 improved cotton resistance when infiltrated at a concentration as low as 4 μg ml(-1), and the highest disease reduction was 38.16 % on the 15th day post V. dahliae inoculation. This protein was able to systemically induce hydrogen peroxide production, nitric oxide generation, lignin deposition, vessel reinforcement and defense enzymes, including phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase. PevD1 also enhanced the expression of three pathogenesis-related genes, namely, β-1,3-glucanase, chitinase, and cadinene synthase, and three key genes, PAL, C4H1, and 4CL, from the cotton defense phenylpropanoid metabolism pathway. Our results demonstrated that PevD1 acted as an effector in cotton and V. dahliae interactions and triggered innate immunity in cotton, resulting in the upregulation of defense-related genes, metabolic substance deposition and cell wall modifications. PevD1 is a candidate plant defense activator for cotton wilt disease control.

  19. Expression of Baculovirus Anti-Apoptotic Genes p35 and op-iap in Cotton (Gossypium hirsutum L.) Enhances Tolerance to Verticillium Wilt

    Science.gov (United States)

    Liang, Benguo; Li, Shanwei; Wu, Zhixia; Wang, Qianhua; Leng, Chunxu; Dong, Jiangli; Wang, Tao

    2010-01-01

    Background Programmed cell death plays an important role in mediating plant adaptive responses to the environment such as the invasion of pathogens. Verticillium wilt, caused by the necrotrophic pathogen Verticillium dahliae, is a serious vascular disease responsible for great economic losses to cotton, but the molecular mechanisms of verticillium disease and effective, safe methods of resistance to verticillium wilt remain unexplored. Methodology/Principal Findings In this study, we introduced baculovirus apoptosis inhibitor genes p35 and op-iap into the genome of cotton via Agrobacterium-mediated transformation and analyzed the response of transgenic plants to verticillium wilt. Results showed that p35 and op-iap constructs were stably integrated into the cotton genome, expressed in the transgenic lines, and inherited through the T3 generation. The transgenic lines had significantly increased tolerance to verticillium wilt throughout the developmental stages. The disease index of T1–T3 generation was lower than 19, significantly (P<0.05) better than the negative control line z99668. After treatment with 250 mg/L VD-toxins for 36 hours, DNA from negative control leaves was fragmented, whereas fragmentation in the transgenic leaf DNA did not occur. The percentage of cell death in transgenic lines increased by 7.11% after 60 mg/L VD-toxin treatment, which was less than that of the negative control lines's 21.27%. This indicates that p35 and op-iap gene expression partially protects cells from VD-toxin induced programmed cell death (PCD). Conclusion/Significance Verticillium dahliae can trigger plant cells to die through induction of a PCD mechanism involved in pathogenesis. This paper provides a potential strategy for engineering broad-spectrum necrotrophic disease resistance in plants. PMID:21151969

  20. Iceberg lettuce breeding lines with resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae.

    Science.gov (United States)

    The Agricultural Research Service, United States Department of Agriculture and the University of California, Davis, announce the release of two breeding lines of lettuce (Lactuca sativa L.). Lines RH08-0472 and RH08-0475 are F9 iceberg type lettuce breeding lines with resistance to Verticillium wil...

  1. Threshold microsclerotial inoculum for cotton verticillium wilt determined through wet-sieving and real-time quantitative PCR.

    Science.gov (United States)

    Wei, Feng; Fan, Rong; Dong, Haitao; Shang, Wenjing; Xu, Xiangming; Zhu, Heqin; Yang, Jiarong; Hu, Xiaoping

    2015-02-01

    Quantification of Verticillium dahliae microsclerotia is an important component of wilt management on a range of crops. Estimation of microsclerotia by dry or wet sieving and plating of soil samples on semiselective medium is a commonly used technique but this method is resource-intensive. We developed a new molecular quantification method based on Synergy Brands (SYBR) Green real-time quantitative polymerase chain reaction of wet-sieving samples (wet-sieving qPCR). This method can detect V. dahliae microsclerotia as low as 0.5 CFU g(-1) of soil. There was a high correlation (r=0.98) between the estimates of conventional plating analysis and the new wet-sieving qPCR method for 40 soil samples. To estimate the inoculum threshold for cotton wilt, >400 soil samples were taken from the rhizosphere of individual plants with or without visual wilt symptoms in experimental and commercial cotton fields at the boll-forming stage. Wilt inoculum was estimated using the wet-sieving qPCR method and related to wilt development. The estimated inoculum threshold varied with cultivar, ranging from 4.0 and 7.0 CFU g(-1) of soil for susceptible and resistant cultivars, respectively. In addition, there was an overall relationship of wilt incidence with inoculum density across 31 commercial fields where a single composite soil sample was taken at each field, with an estimated inoculum threshold of 11 CFU g(-1) of soil. These results suggest that wilt risk can be predicted from the estimated soil inoculum density using the new wet-sieving qPCR method. We recommend the use of 4.0 and 7.0 CFU g(-1) as an inoculum threshold on susceptible and resistant cultivars, respectively, in practical risk prediction schemes.

  2. Identification of pathogenicity-related genes in the vascular wilt fungus verticillium dahliae by agrobacterium tumefaciens-mediated t-DNA insertional mutagenesis.

    Science.gov (United States)

    Verticillium dahliae is the causal agent of vascular wilt in many economically important crops worldwide. Identification of genes that underpin pathogenicity or virulence may suggest targets for alternative control methods for this fungus. In this study, Agrobacterium tumefaciens-mediated transform...

  3. Genotyping-by-sequencing based genome-wide association studies on Verticillium wilt resistance in heterozygous autotetraploid alfalfa (Medicago sativa L.)

    Science.gov (United States)

    Verticillium wilt (VW) is a fungal disease which causes severe yield loss in alfalfa. The most effective method to control the disease is through the development and use of resistant varieties. Identification of gene loci linked to VW resistance will facilitate breeding for the disease-resistant al...

  4. Broad taxonomic characterization of Verticillium wilt resistance genes reveals an ancient origin of the tomato Ve1 immune receptor.

    Science.gov (United States)

    Song, Yin; Zhang, Zhao; Seidl, Michael F; Majer, Aljaz; Jakse, Jernej; Javornik, Branka; Thomma, Bart P H J

    2017-02-01

    Plant-pathogenic microbes secrete effector molecules to establish themselves on their hosts, whereas plants use immune receptors to try and intercept such effectors in order to prevent pathogen colonization. The tomato cell surface-localized receptor Ve1 confers race-specific resistance against race 1 strains of the soil-borne vascular wilt fungus Verticillium dahliae which secrete the Ave1 effector. Here, we describe the cloning and characterization of Ve1 homologues from tobacco (Nicotiana glutinosa), potato (Solanum tuberosum), wild eggplant (Solanum torvum) and hop (Humulus lupulus), and demonstrate that particular Ve1 homologues govern resistance against V. dahliae race 1 strains through the recognition of the Ave1 effector. Phylogenetic analysis shows that Ve1 homologues are widely distributed in land plants. Thus, our study suggests an ancient origin of the Ve1 immune receptor in the plant kingdom. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  5. Early Detection and Quantification of Verticillium Wilt in Olive Using Hyperspectral and Thermal Imagery over Large Areas

    Directory of Open Access Journals (Sweden)

    Rocío Calderón

    2015-05-01

    Full Text Available Automatic methods for an early detection of plant diseases (i.e., visible symptoms at early stages of disease development using remote sensing are critical for precision crop protection. Verticillium wilt (VW of olive caused by Verticillium dahliae can be controlled only if detected at early stages of development. Linear discriminant analysis (LDA and support vector machine (SVM classification methods were applied to classify V. dahliae severity using remote sensing at large scale. High-resolution thermal and hyperspectral imagery were acquired with a manned platform which flew a 3000-ha commercial olive area. LDA reached an overall accuracy of 59.0% and a κ of 0.487 while SVM obtained a higher overall accuracy, 79.2% with a similar κ, 0.495. However, LDA better classified trees at initial and low severity levels, reaching accuracies of 71.4 and 75.0%, respectively, in comparison with the 14.3% and 40.6% obtained by SVM. Normalized canopy temperature, chlorophyll fluorescence, structural, xanthophyll, chlorophyll, carotenoid and disease indices were found to be the best indicators for early and advanced stage infection by VW. These results demonstrate that the methods developed in other studies at orchard scale are valid for flights in large areas comprising several olive orchards differing in soil and crop management characteristics.

  6. Preventing an increase in Verticillium wilt incidence in spinach seed production

    DEFF Research Database (Denmark)

    Olesen, Merete Halkjær; Deleuran, Lise Christina; Gislum, René

    2014-01-01

    A semifield assay was conducted from 2009 to 2011 to distinguish between different preventive methods of reducing Verticillium spp. in spinach seed production. The seed treatments for controlling seed infection levels included Thiram, Signum, Trichoderma harzianum, Gliocladium roseum and Natural II......, and these were tested in naturally infested and uninfested soil. Even though seed treatment by Thiram and Signum in all cases reduced the incidence of Verticillium spp. on the harvested seed, the soil type had a large influence on the subsequent disease pressure as a significant effect of soil was seen in 2010...

  7. Genome-wide association study discovered candidate genes of Verticillium wilt resistance in upland cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Li, Tinggang; Ma, Xuefeng; Li, Nanyang; Zhou, Lei; Liu, Zheng; Han, Huanyong; Gui, Yuejing; Bao, Yuming; Chen, Jieyin; Dai, Xiaofeng

    2017-12-01

    Verticillium wilt (VW), caused by infection by Verticillium dahliae, is considered one of the most yield-limiting diseases in cotton. To examine the genetic architecture of cotton VW resistance, we performed a genome-wide association study (GWAS) using a panel of 299 accessions and 85 630 single nucleotide polymorphisms (SNPs) detected using the specific-locus amplified fragment sequencing (SLAF-seq) approach. Trait-SNP association analysis detected a total of 17 significant SNPs at P resistance on A10 were continuous and common in three environments (RDIG2015, RDIF2015 and RDIF2016). Haplotype block structure analysis predicted 22 candidate genes for VW resistance based on A10_99672586 with a minimum P-value (-log10 P = 6.21). One of these genes (CG02) was near the significant SNP A10_99672586 (0.26 Mb), located in a 372-kb haplotype block, and its Arabidopsis AT3G25510 homologues contain TIR-NBS-LRR domains that may be involved in disease resistance response. Real-time quantitative PCR and virus-induced gene silencing (VIGS) analysis showed that CG02 was specific to up-regulation in the resistant (R) genotype Zhongzhimian2 (ZZM2) and that silenced plants were more susceptible to V. dahliae. These results indicate that CG02 is likely the candidate gene for resistance against V. dahliae in cotton. The identified locus or gene may serve as a promising target for genetic engineering and selection for improving resistance to VW in cotton. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  8. Characterization, Expression, and Functional Analysis of a Novel NAC Gene Associated with Resistance to Verticillium Wilt and Abiotic Stress in Cotton.

    Science.gov (United States)

    Wang, Weina; Yuan, Youlu; Yang, Can; Geng, Shuaipeng; Sun, Quan; Long, Lu; Cai, Chaowei; Chu, Zongyan; Liu, Xin; Wang, Guanghao; Du, Xiongming; Miao, Chen; Zhang, Xiao; Cai, Yingfan

    2016-12-07

    Elucidating the mechanism of resistance to biotic and abiotic stress is of great importance in cotton. In this study, a gene containing the NAC domain, designated GbNAC1, was identified from Gossypium barbadense L. Homologous sequence alignment indicated that GbNAC1 belongs to the TERN subgroup. GbNAC1 protein localized to the cell nucleus. GbNAC1 was expressed in roots, stems, and leaves, and was especially highly expressed in vascular bundles. Functional analysis showed that cotton resistance to Verticillium wilt was reduced when the GbNAC1 gene was silenced using the virus-induced gene silencing (VIGS) method. GbNAC1-overexpressing Arabidopsis showed enhanced resistance to Verticillium dahliae compared to wild-type. Thus, GbNAC1 is involved in the positive regulation of resistance to Verticillium wilt. In addition, analysis of GbNAC1-overexpressing Arabidopsis under different stress treatments indicated that it is involved in plant growth, development, and response to various abiotic stresses (ABA, mannitol, and NaCl). This suggests that GbNAC1 plays an important role in resistance to biotic and abiotic stresses in cotton. This study provides a foundation for further study of the function of NAC genes in cotton and other plants. Copyright © 2016 Wang et al.

  9. VdPKS1 is required for melanin formation and virulence in a cotton wilt pathogen Verticillium dahliae.

    Science.gov (United States)

    Zhang, Ting; Zhang, Bosen; Hua, Chenlei; Meng, Pei; Wang, Sheng; Chen, Zhirong; Du, Yejuan; Gao, Feng; Huang, Jiafeng

    2017-08-01

    Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form of melanized microsclerotia. To investigate the melanin synthesis in V. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in V. dahliae. The VdPKS1 gene-disruption mutant (vdpks1) formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of V. dahliae.

  10. Genotyping-by-sequencing-based genome-wide association studies on Verticillium wilt resistance in autotetraploid alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Yu, Long-Xi; Zheng, Ping; Zhang, Tiejun; Rodringuez, Jonas; Main, Dorrie

    2017-02-01

    Verticillium wilt (VW) is a fungal disease that causes severe yield losses in alfalfa. The most effective method to control the disease is through the development and use of resistant varieties. The identification of marker loci linked to VW resistance can facilitate breeding for disease-resistant alfalfa. In the present investigation, we applied an integrated framework of genome-wide association with genotyping-by-sequencing (GBS) to identify VW resistance loci in a panel of elite alfalfa breeding lines. Phenotyping was performed by manual inoculation of the pathogen to healthy seedlings, and scoring for disease resistance was carried out according to the standard test of the North America Alfalfa Improvement Conference (NAAIC). Marker-trait association by linkage disequilibrium identified 10 single nucleotide polymorphism (SNP) markers significantly associated with VW resistance. Alignment of the SNP marker sequences to the M. truncatula genome revealed multiple quantitative trait loci (QTLs). Three, two, one and five markers were located on chromosomes 5, 6, 7 and 8, respectively. Resistance loci found on chromosomes 7 and 8 in the present study co-localized with the QTLs reported previously. A pairwise alignment (blastn) using the flanking sequences of the resistance loci against the M. truncatula genome identified potential candidate genes with putative disease resistance function. With further investigation, these markers may be implemented into breeding programmes using marker-assisted selection, ultimately leading to improved VW resistance in alfalfa. PUBLISHED 2016. THIS ARTICLE IS A U.S. GOVERNMENT WORK AND IS IN THE PUBLIC DOMAIN IN THE USA.

  11. Detection of Verticillium wilt of olive trees and downy mildew of opium poppy using hyperspectral and thermal UAV imagery

    Science.gov (United States)

    Calderón Madrid, Rocío; Navas Cortés, Juan Antonio; Montes Borrego, Miguel; Landa del Castillo, Blanca Beatriz; Lucena León, Carlos; Jesús Zarco Tejada, Pablo

    2014-05-01

    The present study explored the use of high-resolution thermal, multispectral and hyperspectral imagery as indicators of the infections caused by Verticillium wilt (VW) in olive trees and downy mildew (DM) in opium poppy fields. VW, caused by the soil-borne fungus Verticillium dahliae, and DM, caused by the biotrophic obligate oomycete Peronospora arborescens, are the most economically limiting diseases of olive trees and opium poppy, respectively, worldwide. V. dahliae infects the plant by the roots and colonizes its vascular system, blocking water flow and eventually inducing water stress. P. arborescens colonizes the mesophyll, appearing the first symptoms as small chlorotic leaf lesions, which can evolve to curled and thickened tissues and systemic infections that become deformed and necrotic as the disease develops. The work conducted to detect VW and DM infection consisted on the acquisition of time series of airborne thermal, multispectral and hyperspectral imagery using 2-m and 5-m wingspan electric Unmanned Aerial Vehicles (UAVs) in spring and summer of three consecutive years (2009 to 2011) for VW detection and on three dates in spring of 2009 for DM detection. Two 7-ha commercial olive orchards naturally infected with V. dahliae and two opium poppy field plots artificially infected by P. arborescens were flown. Concurrently to the airborne campaigns, olive orchards and opium poppy fields were assessed "in situ" to assess actual VW severity and DM incidence. Furthermore, field measurements were conducted at leaf and crown level. The field results related to VW detection showed a significant increase in crown temperature (Tc) minus air temperature (Ta) and a decrease in leaf stomatal conductance (G) as VW severity increased. This reduction in G was associated with a significant increase in the Photochemical Reflectance Index (PRI570) and a decrease in chlorophyll fluorescence. DM asymptomatic leaves showed significantly higher NDVI and lower green/red index

  12. Biological control of wilt disease complex on tomato crop caused by Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici by Verticillium leptobactrum.

    Science.gov (United States)

    Hajji-Hedfi, Lobna; Regaieg, Hajer; Larayedh, Asma; Chihani, Noura; Horrigue-Raouani, Najet

    2017-09-23

    The efficacy of Verticillium leptobactrum isolate (HR1) was evaluated in the control of root-knot nematode and Fusarium wilt fungus under laboratory and greenhouse conditions. Five concentrations of V. leptobactrum (HR1) isolate were tested for their nematicidal and fungicidal activities against Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici in vitro. Laboratory trials showed that mycelium growth inhibition of Fusarium wilt fungus was correlated to the increase of the concentration of culture filtrate. All dilutions showed efficiency in reducing the growth of Fusarium oxysporum f.sp. lycopersici. The greatest nematicidal activity was observed at 50, 75, and 100% filtrate dilutions. The egg hatching percentage reached 42%, and the juvenile's corrected mortality registered 90% for the above treatments. In greenhouse experiment, the biocontrol agent fungus enhanced significantly tomato growth components (height and weight of plant and root). The multiplication rate of root-knot nematode and the Fusarium wilt disease incidence declined significantly with soil application of V. leptobactrum as with chemical treatments. The isolate HR1 was efficient to control wilt disease complex caused by M. javanica and Fusarium oxysporum f.sp. lycopersici.

  13. SSH reveals a linkage between a senescence-associated protease and Verticillium wilt symptom development in lettuce (Lactuca sativa)

    Science.gov (United States)

    Suppression subtractive hybridization (SSH) was employed to identify lettuce (Lactuca sativa) genes that are differentially expressed in symptomatic leaves infected with Verticillium dahliae. Genes expressed only in symptomatic leaves included those with homology to pathogenesis-related (PR) protei...

  14. Molecular mapping and validation of a major QTL conferring resistance to a defoliating isolate of verticillium wilt in cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Zhang, Xingju; Yuan, Yanchao; Wei, Ze; Guo, Xian; Guo, Yuping; Zhang, Suqing; Zhao, Junsheng; Zhang, Guihua; Song, Xianliang; Sun, Xuezhen

    2014-01-01

    Verticillium wilt (VW) caused by Verticillium dahliae Kleb is one of the most destructive diseases of cotton. Development and use of a VW resistant variety is the most practical and effective way to manage this disease. Identification of highly resistant genes/QTL and the underlining genetic architecture is a prerequisite for developing a VW resistant variety. A major QTL qVW-c6-1 conferring resistance to the defoliating isolate V991 was identified on chromosome 6 in LHB22×JM11 F2∶3 population inoculated and grown in a greenhouse. This QTL was further validated in the LHB22×NNG F2∶3 population that was evaluated in an artificial disease nursery of V991 for two years and in its subsequent F4 population grown in a field severely infested by V991. The allele conferring resistance within the QTL qVW-c6-1 region originated from parent LHB22 and could explain 23.1-27.1% of phenotypic variation. Another resistance QTL qVW-c21-1 originated from the susceptible parent JM11 was mapped on chromosome 21, explaining 14.44% of phenotypic variation. The resistance QTL reported herein provides a useful tool for breeding a cotton variety with enhanced resistance to VW.

  15. Phylogenetics and taxonomy of the fungal vascular wilt pathogen Verticillium, with the descriptions of five new species.

    Directory of Open Access Journals (Sweden)

    Patrik Inderbitzin

    Full Text Available Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS, partial sequences of the protein coding genes actin (ACT, elongation factor 1-alpha (EF, glyceraldehyde-3-phosphate dehydrogenase (GPD and tryptophan synthase (TS. Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a

  16. Reliable detection of unevenly distributed Verticillium dahliae in diseased olive trees

    NARCIS (Netherlands)

    Keykha Saber, Mojtaba; Pham, K.T.K.; Thomma, B.P.H.J.; Hiemstra, J.A.

    2017-01-01

    Verticillium wilt caused by Verticillium dahliae is one of the most threatening diseases of olive worldwide. For pre-planting and post-planting control of verticillium wilt in olive trees, availability of a rapid, reliable and non-destructive method for detection of V. dahliae is essential. For such

  17. Verticillium survey results: Is it in red raspberry production fields?

    Science.gov (United States)

    Preliminary results of the survey for Verticillium dahliae, the cause of Verticillium wilt, in the Washington Red Raspberry industry were reported at the 2016 Washington Small Fruit Conference. Verticillium was found in many field soils, but was rarely isolated from plants and was just as likely to ...

  18. Biological control of Verticillium dahliae by Talaromyces flavus

    NARCIS (Netherlands)

    Nagtzaam, M.P.M.

    1998-01-01

    Verticillium dahliae causes vascular wilt in a wide range of host plants. Control of Verticillium wilt is by soil disinfestation and to a lesser extent by crop rotation or, for a few host plants, by growing resistant varieties. For environmental reasons, the development

  19. The Impact of Genotyping-by-Sequencing Pipelines on SNP Discovery and Identification of Markers Associated with Verticillium Wilt Resistance in Autotetraploid Alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Yu, Long-Xi; Zheng, Ping; Bhamidimarri, Suresh; Liu, Xiang-Ping; Main, Dorie

    2017-01-01

    Verticillium wilt (VW) of alfalfa is a soilborne disease causing severe yield loss in alfalfa. To identify molecular markers associated with VW resistance, we used an integrated framework of genome-wide association study (GWAS) with high-throughput genotyping by sequencing (GBS) to identify loci associated with VW resistance in an F1 full-sib alfalfa population. Phenotyping was performed using manual inoculation of the pathogen to cloned plants of each individual and disease severity was scored using a standard scale. Genotyping was done by GBS, followed by genotype calling using three bioinformatics pipelines including the TASSEL-GBS pipeline (TASSEL), the Universal Network Enabled Analysis Kit (UNEAK), and the haplotype-based FreeBayes pipeline (FreeBayes). The resulting numbers of SNPs, marker density, minor allele frequency (MAF) and heterozygosity were compared among the pipelines. The TASSEL pipeline generated more markers with the highest density and MAF, whereas the highest heterozygosity was obtained by the UNEAK pipeline. The FreeBayes pipeline generated tetraploid genotypes, with the least number of markers. SNP markers generated from each pipeline were used independently for marker-trait association. Markers significantly associated with VW resistance identified by each pipeline were compared. Similar marker loci were found on chromosomes 5, 6, and 7, whereas different loci on chromosome 1, 2, 3, and 4 were identified by different pipelines. Most significant markers were located on chromosome 6 and they were identified by all three pipelines. Of those identified, several loci were linked to known genes whose functions are involved in the plants' resistance to pathogens. Further investigation on these loci and their linked genes would provide insight into understanding molecular mechanisms of VW resistance in alfalfa. Functional markers closely linked to the resistance loci would be useful for MAS to improve alfalfa cultivars with enhanced resistance to

  20. Study on interaction between root-knot nematode Meloidogyne javanica and wilt fungus Verticillium dahliae on olive seedlings in greenhouse.

    Science.gov (United States)

    Saeedizadeh, A; Kheiri, A; Okhovat, M; Hoseininejad, A

    2003-01-01

    Verticillium dahliae has been reported as a limiting factor in cotton, olive, potato and tomato fields from several countries in the world. Root-knot nematodes Meloidogyne javanica causes considerable damage to olive groves in olive growing areas. Since the presence of these two pathogens in olive trees and seedlings were confirmed in Golestan Province, this study was proposed to find the mode of their action and interaction with olive seedlings in greenhouse. The non-defoliant strain of the fungus (SS-4) was isolated from olive groves showing symptom in Golestan Province. M. javanica was also recovered from the infested olive seedlings. After species identification, it was reared on tomato seedlings var. Rutgers. The larvae were used as a source of inoculum. Conidia and microsclerotia of V. dahliae were used as a source of inoculum for pathogenesis in this study. Stem cuttings of olive cultivar Zard were transplanted in different sets of pots containing 720 ml. of sterilized loamy soil and sandy soil. Experiment was conducted in Completely Randomized Design with 6 treatments and 8 replicates including control, nematode alone, fungus alone, nematode and fungus simultaneously, nematode and fungus concomitantly, fungus two weeks prior to nematode, nematode and fungus concomitantly, nematode two weeks prior to fungus. Pots were inoculated with 1500 larvae of nematodes and 7200 microsclerotia of V. dahliae. Experiment was terminated after 9 months and following parameters were determined i.e. fresh weight of roots, number of galls and females, per root system and discoloration of leaf and root tissues. Presence of nematode prior to fungus caused reduction in colonization of fungus in the roots and the stems and vis presence of fungus prior to nematode caused reduction in number of galls produced by nematode. Sever symptom on aerial parts of plant was observed when both pathogens were inoculated simultaneously. However fresh weight of roots was reduced in all treatments

  1. Lignin metabolism has a central role in the resistance of cotton to the wilt fungus Verticillium dahliae as revealed by RNA-Seq-dependent transcriptional analysis and histochemistry

    National Research Council Canada - National Science Library

    Li Xu; Longfu Zhu; Lili Tu; Linlin Liu; Daojun Yuan; Li Jin; Lu Long; Xianlong Zhang

    2011-01-01

    The incompatible pathosystem between resistant cotton (Gossypium barbadense cv. 7124) and Verticillium dahliae strain V991 was used to study the cotton transcriptome changes after pathogen inoculation by RNA-Seq...

  2. In vitro inhibition of pathogenic Verticillium dahliae , causal agent of ...

    African Journals Online (AJOL)

    In vitro inhibition of pathogenic Verticillium dahliae, causal agent of potato wilt disease in China by Trichoderma isolates. C Xiaojun, S Wongkaew, Y Jie, Y Xuehui, H Haiyong, W Shiping, T Qigqun, W Lishuang, D Athinuwat, N Buensanteai ...

  3. The Brassicaceae-Specific EWR1 Gene Provides Resistance to Vascular Wilt Pathogens

    OpenAIRE

    Yadeta, Koste A.; Dirk-Jan Valkenburg; Mathieu Hanemian; Yves Marco; Thomma, Bart P. H. J.

    2014-01-01

    Soil-borne vascular wilt diseases caused by Verticillium spp. are among the most destructive diseases worldwide in a wide range of plant species. The most effective means of controlling Verticillium wilt diseases is the use of genetic resistance. We have previously reported the identification of four activation-tagged Arabidopsis mutants which showed enhanced resistance to Verticillium wilt. Among these, one mutant also showed enhanced resistance to Ralstonia solanacearum, a bacterial vascula...

  4. Biological control of Verticillium dahliae by Talaromyces flavus

    OpenAIRE

    Nagtzaam, M.P.M.

    1998-01-01

    Verticillium dahliae causes vascular wilt in a wide range of host plants. Control of Verticillium wilt is by soil disinfestation and to a lesser extent by crop rotation or, for a few host plants, by growing resistant varieties. For environmental reasons, the development of alternatives to chemical soil disinfestation is being sought. Biocontrol by microbial agents is one of the options. The potential of Talaromyces flavus as a biocontrol agen...

  5. Colonization of spinach by Verticillium dahliae and effects of pathogen localization on the efficacy of seed treatments

    Science.gov (United States)

    Verticillium wilt is caused by the soilborne fungus V. dahliae on spinach (Spinacia oleracea L.) but the disease is a serious problem only in seed production fields. Spinach crops are harvested well before symptom expression, and thus, Verticillium wilt is not a significant threat in fresh and proc...

  6. Segregation of unknown signaling components in potato complicates marker-assisted selection for Ve-mediated Verticillium resistance

    Science.gov (United States)

    Verticillium wilt (VW), caused primarily by soil-borne fungi Verticillium dahliae Kleb and V. albo-atrum Reinke and Berthold is characterized by unilateral wilting of leaves, chlorosis, and premature senescence. VW is mainly controlled by fumigating fields with metam sodium, which has negative econo...

  7. Host range of Verticillium isaacii and Verticillium klebahnii from artichoke, spinach, and lettuce

    Science.gov (United States)

    Verticillium is a genus that includes major vascular wilt pathogens. The recent multilocus phylogenetic analyses of the genus identified 5 new species including V. isaacii and V. klebahnii, both of which occur in agricultural soils in coastal California, and have been isolated from asymptomatic and ...

  8. Two Lysin-Motif Receptor Kinases, Gh-LYK1 and Gh-LYK2, Contribute to Resistance against Verticillium wilt in Upland Cotton

    Directory of Open Access Journals (Sweden)

    Zhouhang Gu

    2017-12-01

    Full Text Available Lysin-motif (LysM receptor kinases (LYKs play essential roles in recognition of chitin and activation of defense responses against pathogenic fungi in the model plants Arabidopsis and rice. The function of LYKs in non-model plants, however, remains elusive. In the present work, we found that the transcription of two LYK-encoding genes from cotton, Gh-LYK1 and Gh-LYK2, was induced after Verticillium dahliae infection. Virus-induced gene silencing (VIGS of Gh-LYK1 and Gh-LYK2 in cotton plants compromises resistance to V. dahliae. As putative pattern recognition receptors (PRRs, both Gh-LYK1 and Gh-LYK2 are membrane-localized, and all three LysM domains of Gh-LYK1 and Gh-LYK2 are required for their chitin-binding ability. However, since Gh-LYK2, but not Gh-LYK1, is a pseudo-kinase and, on the other hand, the ectodomain (ED of Gh-LYK2 can induce reactive oxygen species (ROS burst in planta, Gh-LYK2 and Gh-LYK1 may contribute differently to cotton defense. Taken together, our results establish that both Gh-LYK1 and Gh-LYK12 are required for defense against V. dahliae in cotton, possibly through different mechanisms.

  9. Verticillium dahliae disease resistance and the regulatory pathway for maturity and tuberization in potato

    DEFF Research Database (Denmark)

    Tai, Helen H.; De Koyer, David; Sønderkær, Mads

    2017-01-01

    Verticillium dahliae Kleb. is a pathogenic fungus causing wilting, chlorosis and early dying in potato. Genetic mapping of resistance to V. dahliae was done using a diploid population of potato. The major quantitative trait locus (QTL) for Verticillium resistance was found on chromosome 5. The St...

  10. Repetitive elements, architects of genomic variation in Verticillium

    Science.gov (United States)

    Vascular wilt pathogens in the genus Verticillium show considerable variation with respect to their host ranges, genomic organization, and the variety and number of transposable elements (TEs) that they carry. These families of TE sequences were first documented in the wide host range, plant pathog...

  11. Ativação de defesa em cacaueiro contra a murcha-de-verticílio por extratos naturais e acibenzolar-S-metil Activation of defence responses on cocoa against Verticillium wilt by natural extracts and acibenzolar-S-methyl

    Directory of Open Access Journals (Sweden)

    Ricardo Borges Pereira

    2008-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o potencial de extratos fúngicos e vegetais na redução da murcha-de-verticílio do cacaueiro, as atividades da peroxidase e polifenoloxidase e o conteúdo de lignina. Mudas de cacaueiro foram pulverizadas com filtrado de micélio de Rhizopus sp. (FMR, quitosana de Rhizopus sp. (QMR e Trichoderma sp. (QMT, extratos de casca in natura e seca de maracujá, extrato metanólico de casca seca de frutos de maracujá (MMS e acibenzolar-S-metil (ASM - 0.2 mg mL-1 e sete dias depois, submetidas à inoculação de Verticillium dahliae. O ASM reduziu a murcha-de-verticílio em 38,0%, seguido dos extratos FMR, QMT, MMS e QMR, que apresentaram reduções em 22,8, 20,1, 19,2 e 15,7%, respectivamente, em relação à testemunha. Plantas pulverizadas com ASM ou FMR seguidas de inoculação apresentaram aumento da atividade de peroxidase aos oito dias após a pulverização, comparadas às respectivas testemunhas, com pico aos 18 dias após a pulverização. ASM e FMR aumentaram a atividade de polifenoloxidase aos quatro dias após a pulverização. Maiores concentrações de lignina foram obtidas em plantas tratadas com FMR e FMR seguido de inoculação. FMR é um potencial indutor de resistência para manejo de murcha-de-verticílio em cacaueiro.The objective of this work was to assess the potential of fungal and plant extracts on the reduction of Verticillium wilt of cocoa, the activities of the enzymes peroxidase and polyphenoloxidase, as well as the lignin content. Seedlings of cocoa were sprayed with the mycelial filtrate of Rhizopus sp. (FMR, chitosan from Rhizopus sp. (QMR and Trichoderma sp. (QMT, extracts of fresh and dry passion fruit peel, methanolic extract from dry passion fruit peel (MMS and acibenzolar-S-methyl (ASM - 0.2 mg mL-1 and, inoculed with Verticillium dahliae, seven days later. ASM reduced the cocoa Verticillium wilt in 38.0%. The extract FMR, QMT, MMS and QMR presented as well reductions of 22

  12. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

    OpenAIRE

    Fu, Xuepeng; Wu, Xia; Zhou, Xingang; Liu, Shouwei; Shen, Yanhui; Wu, Fengzhi

    2015-01-01

    Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae). To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown t...

  13. Proteomic identification of differentially expressed proteins in Gossypium thurberi inoculated with cotton Verticillium dahliae.

    Science.gov (United States)

    Zhao, Fu'an; Fang, Weiping; Xie, Deyi; Zhao, Yuanming; Tang, Zhongjie; Li, Wu; Nie, Lihong; Lv, Shuping

    2012-04-01

    Thurber's cotton (Gossypium thurberi) is the wild relative of cultivated cotton. It is highly resistant to cotton Verticillium wilt, a disease that significantly affects cotton yield and quality. To reveal the mechanism of disease resistance in G. thurberi and to clone resistance-related genes, we used two-dimensional electrophoresis (2-DE) and tandem time-of-flight mass spectrometry (MALDI-TOF-MS) to identify differentially expressed proteins in Thurber's cotton after inoculation with Verticillium dahliae. A total of 57 different protein spots were upregulated, including 52 known proteins representing 11% of the total protein spots. These proteins are involved in resistance to stress and disease, transcriptional regulation, signal transduction, protein processing and degradation, photosynthesis, production capacity, basic metabolism, and other processes. In addition, five disease resistance proteins showed intense upregulation, indicating that resistance genes (R genes) may play a critical role in resistance to Verticillium wilt in Thurber's cotton. Our results suggest that disease and stress resistance are the combined effects of multiple co-expressed genes. This provides a basis for further, detailed investigation into the mechanisms underlying Verticillium wilt resistance of G. thurberi and for cloning essential genes into cotton cultivars to produce Verticillium wilt resistant plants. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Sources of Verticillium dahliae affecting lettuce.

    Science.gov (United States)

    Atallah, Zahi K; Maruthachalam, Karunakaran; Subbarao, Krishna V

    2012-11-01

    ABSTRACT Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.

  15. Frequency of Verticillium Species in Commercial Spinach Fields and Transmission of V. dahliae from Spinach to Subsequent Lettuce Crops.

    Science.gov (United States)

    Short, D P G; Gurung, S; Koike, S T; Klosterman, S J; Subbarao, K V

    2015-01-01

    Verticillium wilt caused by V. dahliae is a devastating disease of lettuce in California (CA). The disease is currently restricted to a small geographic area in central coastal CA, even though cropping patterns in other coastal lettuce production regions in the state are similar. Infested spinach seed has been implicated in the introduction of V. dahliae into lettuce fields but direct evidence linking this inoculum to wilt epidemics in lettuce is lacking. In this study, 100 commercial spinach fields in four coastal CA counties were surveyed to evaluate the frequency of Verticillium species recovered from spinach seedlings and the area under spinach production in each county was assessed. Regardless of the county, V. isaacii was the most frequently isolated species from spinach followed by V. dahliae and, less frequently, V. klebahnii. The frequency of recovery of Verticillium species was unrelated to the occurrence of Verticillium wilt on lettuce in the four counties but was related to the area under spinach production in individual counties. The transmission of V. dahliae from infested spinach seeds to lettuce was investigated in microplots. Verticillium wilt developed on lettuce following two or three plantings of Verticillium-infested spinach, in independent experiments. The pathogen recovered from the infected lettuce from microplots was confirmed as V. dahliae by polymerase chain reaction assays. In a greenhouse study, transmission of a green fluorescence protein-tagged mutant strain of V. dahliae from spinach to lettuce roots was demonstrated, after two cycles of incorporation of infected spinach residue into the soil. This study presents conclusive evidence that V. dahliae introduced via spinach seed can cause Verticillium wilt in lettuce.

  16. Colonization of spinach (Spinacia oleracea L.) by GFP-tagged verticillium dahliae.

    Science.gov (United States)

    The soilborne fungus, Verticillium dahliae, causes wilt in a wide range of hosts, including spinach (Spinacia oleracea L.). The interaction between a green fluorescent protein (GFP)-tagged V. dahliae strain and spinach was studied by confocal laser scanning microscopy. The roots of spinach seedlings...

  17. Plant host range of Verticillium longisporum and microsclerotia density in Swedisch soils

    NARCIS (Netherlands)

    Johansson, A.; Goud, J.C.; Dixelius, C.

    2006-01-01

    Verticillium longisporum is a soil-borne fungal pathogen causing vascular wilt of Brassica crops. This study was conducted to enhance our knowledge on the host range of V. longisporum. Seven crop species (barley, oat, oilseed rape, pea, red clover, sugar beet and wheat) and five weed species (barren

  18. Data integration and knowledge management to facilitate research on plant-pathogen interactions: case study Solanum tuberosum – Verticillium

    Science.gov (United States)

    Verticillium wilt is an important disease causing considerable economic losses in potato production globally. Soil and environmental conditions affect symptom expression and the effect of the disease on yield. A ten year field trial has been conducted in order to better understand the dynamics of wi...

  19. Transcriptomic analysis of the Olea europaea L. roots during the Verticillium dahliae early infection process

    DEFF Research Database (Denmark)

    Jiménez-Ruiz, Jaime; Pérez, Maria De la O Leyva; Schilirò, Elisabetta

    2017-01-01

    Olive cultivation is affected by a wide range of biotic constraints. Verticillium wilt of olive is one of the most devastating diseases affecting this woody crop, inflicting major economic losses in many areas, particularly within the Mediterranean Basin. Little is known about gene-expression cha...

  20. Cotton gene expression profiles in resistant Gossypium hirsutum cv. Zhongzhimian KV1 responding to Verticillium dahliae strain V991 infection.

    Science.gov (United States)

    Zhang, Wen-Wei; Jian, Gui-Liang; Jiang, Teng-Fei; Wang, Sheng-Zheng; Qi, Fang-Jun; Xu, Shi-Chang

    2012-10-01

    Verticillium wilt of cotton (Gossypium hirsutum) is a widespread and destructive disease that is caused by the soil-borne fungus pathogen Verticillium dahliae (V. dahliae). To study the molecular mechanism in wilt tolerance, suppression subtractive hybridization (SSH) and dot blot techniques were used to identify the specifically expressed genes in a superior wilt-resistant cotton cultivar (G. hirsutum cv. Zhongzhimian KV1) after inoculation with pathogen. cDNAs from the root tissues of Zhongzhimian KV1 inoculated with V. dahliae strain V991 or water mock were used to construct the libraries that contain 4800 clones. Based on the results from dot blot analysis, 147 clones were clearly induced by V. dahliae and selected from the SSH libraries for sequencing. A total of 92 up-regulated and 7 down-regulated non-redundant expressed sequences tags (ESTs) were identified as disease responsive genes and classified into 9 functional groups. Two important clues regarding wilt-resistant G. hirsutum were obtained from this study. One was Bet v 1 family; the other was UbI gene family that may play an important role in the defense reaction against Verticillium wilt. The result from real-time quantitative reverse transcription polymerase chain reaction showed that these genes were activated quickly and transiently after inoculation with V. dahliae.

  1. Comparative genomics yields insights into niche adaptation of plant vascular wilt pathogens.

    Directory of Open Access Journals (Sweden)

    Steven J Klosterman

    2011-07-01

    Full Text Available The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual crop losses. The characteristic wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels, which undergo fluctuations in osmolarity. To gain insights into the mechanisms that confer the organisms' pathogenicity and enable them to proliferate in the unique ecological niche of the plant vascular system, we sequenced the genomes of V. dahliae and V. albo-atrum and compared them to each other, and to the genome of Fusarium oxysporum, another fungal wilt pathogen. Our analyses identified a set of proteins that are shared among all three wilt pathogens, and present in few other fungal species. One of these is a homolog of a bacterial glucosyltransferase that synthesizes virulence-related osmoregulated periplasmic glucans in bacteria. Pathogenicity tests of the corresponding V. dahliae glucosyltransferase gene deletion mutants indicate that the gene is required for full virulence in the Australian tobacco species Nicotiana benthamiana. Compared to other fungi, the two sequenced Verticillium genomes encode more pectin-degrading enzymes and other carbohydrate-active enzymes, suggesting an extraordinary capacity to degrade plant pectin barricades. The high level of synteny between the two Verticillium assemblies highlighted four flexible genomic islands in V. dahliae that are enriched for transposable elements, and contain duplicated genes and genes that are important in signaling/transcriptional regulation and iron/lipid metabolism. Coupled with an enhanced capacity to degrade plant materials, these genomic islands may contribute to the expanded genetic diversity and virulence of V. dahliae, the primary causal agent of Verticillium wilts. Significantly, our study reveals insights into the genetic mechanisms of niche adaptation of fungal wilt pathogens, advances our understanding of

  2. Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes.

    Science.gov (United States)

    Calderón, Rocío; Lucena, Carlos; Trapero-Casas, José L; Zarco-Tejada, Pablo J; Navas-Cortés, Juan A

    2014-01-01

    Development of Verticillium wilt in olive, caused by the soil-borne fungus Verticillium dahliae, can be influenced by biotic and environmental factors. In this study we modeled i) the combined effects of biotic factors (i.e., pathotype virulence and cultivar susceptibility) and abiotic factors (i.e., soil temperature) on disease development and ii) the relationship between disease severity and several remote sensing parameters and plant stress indicators. Plants of Arbequina and Picual olive cultivars inoculated with isolates of defoliating and non-defoliating V. dahliae pathotypes were grown in soil tanks with a range of soil temperatures from 16 to 32°C. Disease progression was correlated with plant stress parameters (i.e., leaf temperature, steady-state chlorophyll fluorescence, photochemical reflectance index, chlorophyll content, and ethylene production) and plant growth-related parameters (i.e., canopy length and dry weight). Disease development in plants infected with the defoliating pathotype was faster and more severe in Picual. Models estimated that infection with the defoliating pathotype was promoted by soil temperatures in a range of 16 to 24°C in cv. Picual and of 20 to 24°C in cv. Arbequina. In the non-defoliating pathotype, soil temperatures ranging from 16 to 20°C were estimated to be most favorable for infection. The relationship between stress-related parameters and disease severity determined by multinomial logistic regression and classification trees was able to detect the effects of V. dahliae infection and colonization on water flow that eventually cause water stress. Chlorophyll content, steady-state chlorophyll fluorescence, and leaf temperature were the best indicators for Verticillium wilt detection at early stages of disease development, while ethylene production and photochemical reflectance index were indicators for disease detection at advanced stages. These results provide a better understanding of the differential geographic

  3. Reactions of selected eggplant cultivars and lines to verticillium wilt ...

    African Journals Online (AJOL)

    The wild species Solanum torvum and Solanum sodemeum; the resistant cultivated forms DK-1, DK-2, DK-3, DK-4 and DK-6; and the cultivar DK-5 were also included in the study. For the pathogenicity tests, an isolate of V. dahliae used was identified by PCR at the Plant Protection Department of the Faculty of Agriculture, ...

  4. Effect of solarization with fresh chicken manure on verticillium wilt ...

    African Journals Online (AJOL)

    BİM

    2016-12-28

    Dec 28, 2016 ... plot design, solarization of main plots, sub-plots with fresh chicken manure and V dahliae inoculation were established as a mini parcel in experiment with three replications. .... inoculum was kept in a freezer until it was inoculated in experimental plots. Inoculation of V. dahliae, transplanting of eggplant ...

  5. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae

    OpenAIRE

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings sugge...

  6. Salicylic acid-related cotton (Gossypium arboreum) ribosomal protein GaRPL18 contributes to resistance to Verticillium dahliae.

    Science.gov (United States)

    Gong, Qian; Yang, Zhaoen; Wang, Xiaoqian; Butt, Hamama Islam; Chen, Eryong; He, Shoupu; Zhang, Chaojun; Zhang, Xueyan; Li, Fuguang

    2017-03-03

    Verticillium dahliae is a phytopathogenic fungal pathogen that causes vascular wilt diseases responsible for considerable decreases in cotton yields. The complex mechanism underlying cotton resistance to Verticillium wilt remains uncharacterized. Identifying an endogenous resistance gene may be useful for controlling this disease. We cloned the ribosomal protein L18 (GaRPL18) gene, which mediates resistance to Verticillium wilt, from a wilt-resistant cotton species (Gossypium arboreum). We then characterized the function of this gene in cotton and Arabidopsis thaliana plants. GaRPL18 encodes a 60S ribosomal protein subunit important for intracellular protein biosynthesis. However, previous studies revealed that some ribosomal proteins are also inhibitory toward oncogenesis and congenital diseases in humans and play a role in plant disease defense. Here, we observed that V. dahliae infections induce GaRPL18 expression. Furthermore, we determined that the GaRPL18 expression pattern is consistent with the disease resistance level of different cotton varieties. GaRPL18 expression is upregulated by salicylic acid (SA) treatments, suggesting the involvement of GaRPL18 in the SA signal transduction pathway. Virus-induced gene silencing technology was used to determine whether the GaRPL18 expression level influences cotton disease resistance. Wilt-resistant cotton species in which GaRPL18 was silenced became more susceptible to V. dahliae than the control plants because of a significant decrease in the abundance of immune-related molecules. We also transformed A. thaliana ecotype Columbia (Col-0) plants with GaRPL18 according to the floral dip method. The plants overexpressing GaRPL18 were more resistant to V. dahliae infections than the wild-type Col-0 plants. The enhanced resistance of transgenic A. thaliana plants to V. dahliae is likely mediated by the SA pathway. Our findings provide new insights into the role of GaRPL18, indicating that it plays a crucial role in

  7. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Directory of Open Access Journals (Sweden)

    M. Mercedes eMaldonado-González

    2015-04-01

    Full Text Available The effective management of Verticillium wilts, diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control Verticillium wilt of olive caused by the highly-virulent, defoliating (D pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V.dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i olive D and non-defoliating (ND V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii strain PICF7 controls Verticillium wilt (VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. Arabidopsis thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7.

  8. The ascomycete Verticillium longisporum is a hybrid and a plant pathogen with an expanded host range.

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    Patrik Inderbitzin

    Full Text Available Hybridization plays a central role in plant evolution, but its overall importance in fungi is unknown. New plant pathogens are thought to arise by hybridization between formerly separated fungal species. Evolution of hybrid plant pathogens from non-pathogenic ancestors in the fungal-like protist Phytophthora has been demonstrated, but in fungi, the most important group of plant pathogens, there are few well-characterized examples of hybrids. We focused our attention on the hybrid and plant pathogen Verticillium longisporum, the causal agent of the Verticillium wilt disease in crucifer crops. In order to address questions related to the evolutionary origin of V. longisporum, we used phylogenetic analyses of seven nuclear loci and a dataset of 203 isolates of V. longisporum, V. dahliae and related species. We confirmed that V. longisporum was diploid, and originated three different times, involving four different lineages and three different parental species. All hybrids shared a common parent, species A1, that hybridized respectively with species D1, V. dahliae lineage D2 and V. dahliae lineage D3, to give rise to three different lineages of V. longisporum. Species A1 and species D1 constituted as yet unknown taxa. Verticillium longisporum likely originated recently, as each V. longisporum lineage was genetically homogenous, and comprised species A1 alleles that were identical across lineages.

  9. Enhanced production of microsclerotia in recalcitrant Verticillium dahliae isolates and its use for inoculation of olive plants.

    Science.gov (United States)

    Varo, A; Raya-Ortega, M C; Trapero, A

    2016-08-01

    The optimization of a simple protocol for the mass production of viable microsclerotia (MS) of Verticillium spp., even for recalcitrant isolates, to the inoculation of olive cuttings. Four Verticillium spp. isolates were characterized by growth rate and morphology. Then, the production ability and the viability of MS over time were assessed in seven solid culture media and five aqueous media. The best culture medium, according to the quantity and the quality (size) of the MS produced, was the alkaline-modified sodium polipectate (AMSP) aqueous medium. The MS viability was higher in peat moss substrates. Finally, the MS obtained in this work were infective causing 100% incidence of Verticillium wilt (VW) disease in inoculated olive plants. This study demonstrates that the modified sodium polipectate medium amended with 0·1% agar is the most suitable for the production of MS of Verticillium dahliae isolates that have lost the ability to produce MS in standard culture media. Mass production of MS for artificial infestation of soil is critical to the study of epidemiological and control aspects of the VW. To overcome the failure in the production of MS in recalcitrant isolates, a culture media was optimized and a successful plant inoculation experiment was carried out with artificial MS. © 2016 The Society for Applied Microbiology.

  10. Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes.

    Directory of Open Access Journals (Sweden)

    Rocío Calderón

    Full Text Available Development of Verticillium wilt in olive, caused by the soil-borne fungus Verticillium dahliae, can be influenced by biotic and environmental factors. In this study we modeled i the combined effects of biotic factors (i.e., pathotype virulence and cultivar susceptibility and abiotic factors (i.e., soil temperature on disease development and ii the relationship between disease severity and several remote sensing parameters and plant stress indicators.Plants of Arbequina and Picual olive cultivars inoculated with isolates of defoliating and non-defoliating V. dahliae pathotypes were grown in soil tanks with a range of soil temperatures from 16 to 32°C. Disease progression was correlated with plant stress parameters (i.e., leaf temperature, steady-state chlorophyll fluorescence, photochemical reflectance index, chlorophyll content, and ethylene production and plant growth-related parameters (i.e., canopy length and dry weight.Disease development in plants infected with the defoliating pathotype was faster and more severe in Picual. Models estimated that infection with the defoliating pathotype was promoted by soil temperatures in a range of 16 to 24°C in cv. Picual and of 20 to 24°C in cv. Arbequina. In the non-defoliating pathotype, soil temperatures ranging from 16 to 20°C were estimated to be most favorable for infection. The relationship between stress-related parameters and disease severity determined by multinomial logistic regression and classification trees was able to detect the effects of V. dahliae infection and colonization on water flow that eventually cause water stress.Chlorophyll content, steady-state chlorophyll fluorescence, and leaf temperature were the best indicators for Verticillium wilt detection at early stages of disease development, while ethylene production and photochemical reflectance index were indicators for disease detection at advanced stages. These results provide a better understanding of the differential

  11. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Xuepeng eFu

    2015-09-01

    Full Text Available Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae. To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related

  12. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae.

    Science.gov (United States)

    Fu, Xuepeng; Wu, Xia; Zhou, Xingang; Liu, Shouwei; Shen, Yanhui; Wu, Fengzhi

    2015-01-01

    Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae). To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related to disease

  13. Bacillus thuringiensis and Bacillus weihenstephanensis Inhibit the Growth of Phytopathogenic Verticillium Species.

    Science.gov (United States)

    Hollensteiner, Jacqueline; Wemheuer, Franziska; Harting, Rebekka; Kolarzyk, Anna M; Diaz Valerio, Stefani M; Poehlein, Anja; Brzuszkiewicz, Elzbieta B; Nesemann, Kai; Braus-Stromeyer, Susanna A; Braus, Gerhard H; Daniel, Rolf; Liesegang, Heiko

    2016-01-01

    Verticillium wilt causes severe yield losses in a broad range of economically important crops worldwide. As many soil fumigants have a severe environmental impact, new biocontrol strategies are needed. Members of the genus Bacillus are known as plant growth-promoting bacteria (PGPB) as well as biocontrol agents of pests and diseases. In this study, we isolated 267 Bacillus strains from root-associated soil of field-grown tomato plants. We evaluated the antifungal potential of 20 phenotypically diverse strains according to their antagonistic activity against the two phytopathogenic fungi Verticillium dahliae and Verticillium longisporum. In addition, the 20 strains were sequenced and phylogenetically characterized by multi-locus sequence typing (MLST) resulting in 7 different Bacillus thuringiensis and 13 Bacillus weihenstephanensis strains. All B. thuringiensis isolates inhibited in vitro the tomato pathogen V. dahliae JR2, but had only low efficacy against the tomato-foreign pathogen V. longisporum 43. All B. weihenstephanensis isolates exhibited no fungicidal activity whereas three B. weihenstephanensis isolates showed antagonistic effects on both phytopathogens. These strains had a rhizoid colony morphology, which has not been described for B. weihenstephanensis strains previously. Genome analysis of all isolates revealed putative genes encoding fungicidal substances and resulted in identification of 304 secondary metabolite gene clusters including 101 non-ribosomal polypeptide synthetases and 203 ribosomal-synthesized and post-translationally modified peptides. All genomes encoded genes for the synthesis of the antifungal siderophore bacillibactin. In the genome of one B. thuringiensis strain, a gene cluster for zwittermicin A was detected. Isolates which either exhibited an inhibitory or an interfering effect on the growth of the phytopathogens carried one or two genes encoding putative mycolitic chitinases, which might contribute to antifungal activities

  14. Aerial Warfare: A Volatile Dialogue between the Plant Pathogen Verticillium longisporum and Its Antagonist Paenibacillus polymyxa.

    Science.gov (United States)

    Rybakova, Daria; Rack-Wetzlinger, Ute; Cernava, Tomislav; Schaefer, Angelika; Schmuck, Maria; Berg, Gabriele

    2017-01-01

    Verticillium wilt caused by Verticillium spp. results in severe yield losses in a broad range of crops. Verticillium outbreaks are challenging to control, and exacerbated by increases in soil temperatures and drought associated with global warming. Employing natural antagonists as biocontrol agents offers a promising approach to addressing this challenge. Paenibacillus polymyxa Sb3-1 was proven to reduce the growth of Verticillium longisporum during in vitro experiments and was shown to promote the growth of oilseed rape seedlings infested with V. longisporum. Our novel approach combined in vitro and in planta methods with the study of the mode of interaction between Sb3-1 and V. longisporum EVL43 via their volatile organic compounds (VOCs). Volatile and soluble substances, produced by both microorganisms as a reaction to one another's VOCs, were detected by using both gas and liquid chromatography-mass spectrometry. P. polymyxa Sb3-1 continually produced antimicrobial and plant growth promoting VOCs, such as 2-nonanone and 3-hydroxy-2-butanone. Several other antimicrobial volatile substances, such as isoamyl acetate and durenol, were downregulated. The general metabolic activity of Sb3-1, including protein and DNA biotransformations, was upregulated upon contact with EVL43 VOCs. V. longisporum increased its production of antimicrobial substances, such as 1-butanol, and downregulated its metabolic activities upon exposure to Sb3-1 VOCs. Additionally, several stress response substances such as arabitol and protein breakdown products (e.g., L-Isoleucyl-L-glutamic acid), were increased in the co-incubated samples. The results obtained depict an ongoing dialog between these microorganisms resulting in growth inhibition, the slowing down of metabolism, and the cell death of V. longisporum due to contact with the P. polymyxa Sb3-1 VOCs. Moreover, the results indicate that VOCs make a substantial contribution to the interaction between pathogens and their natural

  15. Aerial Warfare: A Volatile Dialogue between the Plant Pathogen Verticillium longisporum and Its Antagonist Paenibacillus polymyxa

    Directory of Open Access Journals (Sweden)

    Daria Rybakova

    2017-07-01

    Full Text Available Verticillium wilt caused by Verticillium spp. results in severe yield losses in a broad range of crops. Verticillium outbreaks are challenging to control, and exacerbated by increases in soil temperatures and drought associated with global warming. Employing natural antagonists as biocontrol agents offers a promising approach to addressing this challenge. Paenibacillus polymyxa Sb3-1 was proven to reduce the growth of Verticillium longisporum during in vitro experiments and was shown to promote the growth of oilseed rape seedlings infested with V. longisporum. Our novel approach combined in vitro and in planta methods with the study of the mode of interaction between Sb3-1 and V. longisporum EVL43 via their volatile organic compounds (VOCs. Volatile and soluble substances, produced by both microorganisms as a reaction to one another's VOCs, were detected by using both gas and liquid chromatography-mass spectrometry. P. polymyxa Sb3-1 continually produced antimicrobial and plant growth promoting VOCs, such as 2-nonanone and 3-hydroxy-2-butanone. Several other antimicrobial volatile substances, such as isoamyl acetate and durenol, were downregulated. The general metabolic activity of Sb3-1, including protein and DNA biotransformations, was upregulated upon contact with EVL43 VOCs. V. longisporum increased its production of antimicrobial substances, such as 1-butanol, and downregulated its metabolic activities upon exposure to Sb3-1 VOCs. Additionally, several stress response substances such as arabitol and protein breakdown products (e.g., L-Isoleucyl-L-glutamic acid, were increased in the co-incubated samples. The results obtained depict an ongoing dialog between these microorganisms resulting in growth inhibition, the slowing down of metabolism, and the cell death of V. longisporum due to contact with the P. polymyxa Sb3-1 VOCs. Moreover, the results indicate that VOCs make a substantial contribution to the interaction between pathogens and

  16. AAC as a Potential Target Gene to Control Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Xiaofeng Su

    2017-01-01

    Full Text Available Verticillium dahliae invades the roots of host plants and causes vascular wilt, which seriously diminishes the yield of cotton and other important crops. The protein AAC (ADP, ATP carrier is responsible for transferring ATP from the mitochondria into the cytoplasm. When V. dahliae protoplasts were transformed with short interfering RNAs (siRNAs targeting the VdAAC gene, fungal growth and sporulation were significantly inhibited. To further confirm a role for VdAAC in fungal development, we generated knockout mutants (ΔVdACC. Compared with wild-type V. dahliae (Vd wt, ΔVdAAC was impaired in germination and virulence; these impairments were rescued in the complementary strains (ΔVdAAC-C. Moreover, when an RNAi construct of VdAAC under the control of the 35S promoter was used to transform Nicotiana benthamiana, the expression of VdAAC was downregulated in the transgenic seedlings, and they had elevated resistance against V. dahliae. The results of this study suggest that VdAAC contributes to fungal development, virulence and is a promising candidate gene to control V. dahliae. In addition, RNAi is a highly efficient way to silence fungal genes and provides a novel strategy to improve disease resistance in plants.

  17. Characterization of a novel single-stranded RNA mycovirus related to invertebrate viruses from the plant pathogen Verticillium dahliae.

    Science.gov (United States)

    Cañizares, M Carmen; López-Escudero, Francisco J; Pérez-Artés, Encarnación; García-Pedrajas, María D

    2017-11-16

    Fungal viruses, also known as mycoviruses, are widespread in all major groups of fungi. Mycoviruses from plant pathogens can reduce the virulence of their host fungus and have therefore potential as biological control agents. This has spurred the identification of novel mycoviruses in plant pathogens, research which is greatly contributing to our understanding of these organisms. In this work, we report the characterization of a novel monopartite mycovirus from Verticillium dahliae, the main causal agent of Verticillium wilt. This novel mycovirus, which we termed Verticillium dahliae RNA virus 1 (VdRV1), was identified in three different isolates of V. dahliae collected in olive growing areas of the Guadalquivir valley, southern Spain. We determined that the VdRV1 genome is a positive (+) single-stranded (ss) RNA, 2631 nucleotides in length, containing two open reading frames. VdRV1 showed few similarities with known mycoviruses, only with a group of unassigned (+) ssRNA mycoviruses which are related to plant viruses classified within the family Tombusviridae. However, phylogenetic analysis revealed that VdRV1 and the unassigned (+) ssRNA mycoviruses have a closer relationship with recently reported invertebrate viruses. This result indicates that as more viral sequences become available, the relationships of mycoviruses with viruses from other hosts should be reexamined. Additionally, the work supports the hypothesis of a heterogeneous origin for mycoviruses.

  18. Characterization of a Novel Cotton Subtilase Gene GbSBT1 in Response to Extracellular Stimulations and Its Role in Verticillium Resistance.

    Science.gov (United States)

    Duan, Xingpeng; Zhang, Zhidong; Wang, Jin; Zuo, Kaijing

    2016-01-01

    Verticillium wilt is a disastrous vascular disease in plants caused by Verticillium dahliae. Verticillium pathogens secrete various disease-causing effectors in cotton. This study identified a subtilase gene GbSBT1 from Gossypium babardense and investigated the roles against V. dahliae infection. GbSBT1 gene expression is responsive to V. dahliae defense signals, jasmonic acid, and ethylene treatments. Moreover, the GbSBT1 protein is mainly localized in the cell membrane and moves into the cytoplasm following jasmonic acid and ethylene treatments. Silencing GbSBT1 gene expression through virus-induced GbSBT1 gene silencing reduced the tolerance of Pima-90 (resistant genotype), but not facilitated the infection process of V. dahliae in Coker-312 (sensitive genotype). Moreover, the ectopically expressed GbSBT1 gene enhanced the resistance of Arabidopsis to Fusarium oxysporum and V. dahliae infection and activated the expression levels of defense-related genes. Furthermore, pull-down, yeast two-hybrid assay, and BiFC analysis revealed that GbSBT1 interacts with a prohibitin (PHB)-like protein expressed in V. dahliae pathogens during infection. In summary, GbSBT1 recognizes the effector PHB protein secreted from V. dahliae and is involved in Verticillium-induced resistance in cotton.

  19. Fusarium Wilt of Orchids

    Science.gov (United States)

    Fusarium wilt of orchids is highly destructive and economically limiting to the production of quality orchids that has steadily increased in many production facilities. Important crops such as phalaenopsis, cattleyas, and oncidiums appear to be especially susceptible to certain Fusarium species. Fu...

  20. Analysis of upland cotton (Gossypium hirsutum) response to Verticillium dahliae inoculation by transcriptome sequencing.

    Science.gov (United States)

    Shao, B X; Zhao, Y L; Chen, W; Wang, H M; Guo, Z J; Gong, H Y; Sang, X H; Cui, Y L; Wang, C H

    2015-10-27

    Verticillium wilt is one of the main diseases in cotton (Gossypium hirsutum), severely reduces yield and fiber quality, and is difficult to be con-trolled effectively. At present, the molecular mechanism that confers resistance to this disease is unclear. Transcriptome sequencing is an important method to detect resistance genes, explore metabolic pathways, and study resistance mechanisms. In this study, the transcriptome of a disease-resistant inbred cot-ton line inoculated with Verticillium dahliae was sequenced. A total of 126,402 unigenes were obtained using de novo assembly and data analysis, 99,712 (78.88%) of which were annotated into the Nr, Nt, Swiss-Prot, KEGG, COG, and GO databases. The expression patterns of 16 candidate disease-resis-tance genes showed that some genes were upregulated soon after V. dahliae inoculation and others were upregulated later, which may indicate instanta-neous basal defense and lagged specific defense, respectively. We conducted a preliminary analysis of the transcriptome database, which will contribute to further research regarding the cloning of disease-resistance genes.

  1. Comparative Proteomic Analysis of Gossypium thurberi in Response to Verticillium dahliae Inoculation

    Directory of Open Access Journals (Sweden)

    Weiping Fang

    2015-10-01

    Full Text Available Verticillium wilt is threatening cotton productivity globally. This disease is caused by soil-borne Verticillium dahliae which directly infects cotton roots, and exclusively colonizes and occludes xylem vessels, finally resulting in necrosis, defoliation, and most severely, plant death. For the first time, iTRAQ (isobaric tags for relative and absolute quantification was applied to screen the differentially expressed proteins of Gossypium thurberi inoculated with V. dahliae. A total of 6533 proteins were identified from the roots of G. thurberi after inoculation with V. dahliae, and 396 showed up- and 279 down-regulated in comparison to a mock-inoculated roots. Of these identified proteins, the main functional groups were those involved in cell wall organization and reinforcement, disease-resistant chemicals of secondary metabolism, phytohormone signaling, pathogenesis-related proteins, and disease-resistant proteins. Physiological and biochemical analysis showed that peroxidase activity, which promotes the biosynthesis and accumulation of lignin, was induced early in the hypocotyl after inoculation with V. dahliae. Similarly, salicylic acid also accumulated significantly in hypocotyl of the seedlings after inoculation. These findings provide an important knowledge of the molecular events and regulatory networks occurring during G. thurberi-V. dahliae interaction, which may provide a foundation for breeding disease-resistance in cotton.

  2. Genetic Diversity of Verticillium dahliae Isolates from Olive Trees in Algeria

    Directory of Open Access Journals (Sweden)

    M. Bellahcene

    2005-12-01

    Full Text Available Verticillium wilt of olive trees (Olea europaea L., a wilt caused by the soil-borne fungus Verticillium dahliae (Kleb, is one of the most serious diseases in Algerian olive groves. To assess the pathogenic and genetic diversity of olive-infecting V. dahliae populations in Algeria, orchards from the two main olive-producing regions (north-western Algeria and Kabylia were sampled and 27 V. dahliae isolates were recovered. For purposes of comparison, V. dahliae strains from France and Syria were added to the analysis. By means of PCR primers that specifically discriminate between defoliating (D and non-defoliating (ND V. dahliae pathotypes it was shown that all V. dahliae isolates belonged to the ND pathotype. The amount of genetic variation between the 43 isolates was assessed by random amplification of polymorphic DNA (RAPD. A total of 16 RAPD haplotypes were found on the basis of the presence or absence of 25 polymorphic DNA fragments. Genotypic diversity between the 27 Algerian isolates was low, with two RAPD haplotypes accounting for 70% of all isolates. Genotypic diversity was however greater between isolates from Kabylia than between isolates from north-western Algeria. Cluster analysis showed that most of the Algerian V. dahliae isolates grouped together with the French and Syrian isolates. On the basis of their ability to form heterokaryons with each other, a subset of 25 olive-pathogenic isolates was grouped into a single vegetative compatibility group (VCG. These results suggest that the olive-infecting V. dahliae populations in Algeria show limited diversity and that caution should be taken to prevent introduction of the D pathotype.

  3. Evaluation of Verticillium chlamydosporium and Arthrobotrys ...

    African Journals Online (AJOL)

    The ability of nematode trapping fungi and egg-parasitising fungi to colonize and persist in the rhizosphere of crop plants is thought to be an important factor influencing the success of biological control of root infecting nematodes. In this study, two strains of an egg parasitic fungus Verticillium chlamydosporium (Vc- 10 and ...

  4. Fusarium Wilt of Banana.

    Science.gov (United States)

    Ploetz, Randy C

    2015-12-01

    Banana (Musa spp.) is one of the world's most important fruits. In 2011, 145 million metric tons, worth an estimated $44 billion, were produced in over 130 countries. Fusarium wilt (also known as Panama disease) is one of the most destructive diseases of this crop. It devastated the 'Gros Michel'-based export trades before the mid-1900s, and threatens the Cavendish cultivars that were used to replace it; in total, the latter cultivars are now responsible for approximately 45% of all production. An overview of the disease and its causal agent, Fusarium oxysporum f. sp. cubense, is presented below. Despite a substantial positive literature on biological, chemical, or cultural measures, management is largely restricted to excluding F. oxysporum f. sp. cubense from noninfested areas and using resistant cultivars where the pathogen has established. Resistance to Fusarium wilt is poor in several breeding targets, including important dessert and cooking cultivars. Better resistance to this and other diseases is needed. The history and impact of Fusarium wilt is summarized with an emphasis on tropical race 4 (TR4), a 'Cavendish'-killing variant of the pathogen that has spread dramatically in the Eastern Hemisphere.

  5. Biochemical indices of hop resistance to Verticillium albo-atrum and Fusarium sambucinum

    Directory of Open Access Journals (Sweden)

    Jan Piotrowski

    2013-12-01

    Full Text Available The contents of total phenolic compounds, chlorogenic acid and peroxidase activity as well as monophenols to polyphenols ratio were studies in the suckers of the hops as indices of resistance to Verticillium albo-atrum and Fusarium sambucinum. The suckers of hop taken in the early spring from the healthy and infected plots were used in the experiments. As a research material were included cv. 'Northern Brewer' - a wilt tolerant variety, two wild susceptible varieties - cv. 'Lubelski' and cv. 'Brewers Gold', four breeding clones and one male plant. It was found that, 'Northern Brewer' contains more total phenolic compounds, rnonophenols and chlorogenic acid, and in particular considerably higher peroxidase activity as compared to cv. 'Lubelski'. Taking into consideration the contents of these compounds, in the majority of cases, the new breeding clones were similar to the mother variety 'Northern Brewer'. It seems resonable to assume, that the new clones should be more wilt tolerant than varieties and populations cultivated in our country.

  6. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  7. ( Elaeis guineensis Jacq ) vascular wilt

    African Journals Online (AJOL)

    Effet de la jachére sur l'expérimentation de la fusariose vasculaire du palmier à huile ( Elaeis guineensis Jacq ) : Effects of the fallow in the expression of oil-palm ( Elaeis guineensis Jacq ) vascular wilt.

  8. Comparative transcriptional analysis of hop responses to infection with Verticillium nonalfalfae.

    Science.gov (United States)

    Progar, Vasja; Jakše, Jernej; Štajner, Nataša; Radišek, Sebastjan; Javornik, Branka; Berne, Sabina

    2017-10-01

    Dynamic transcriptome profiling revealed excessive, yet ineffective, immune response to V. nonalfalfae infection in susceptible hop, global gene downregulation in shoots of resistant hop and only a few infection-associated genes in roots. Hop (Humulus lupulus L.) production is hampered by Verticillium wilt, a disease predominantly caused by the soil-borne fungus Verticillium nonalfalfae. Only a few hop cultivars exhibit resistance towards it and mechanisms of this resistance have not been discovered. In this study, we compared global transcriptional responses in roots and shoots of resistant and susceptible hop plants infected by a lethal strain of V. nonalfalfae. Time-series differential gene expression profiles between infected and mock inoculated plants were determined and subjected to network-based analysis of functional enrichment. In the resistant hop cultivar, a remarkably low number of genes were differentially expressed in roots in response to V. nonalfalfae infection, while the majority of differentially expressed genes were down-regulated in shoots. The most significantly affected genes were related to cutin biosynthesis, cell wall biogenesis, lateral root development and terpenoid biosynthesis. On the other hand, susceptible hop exhibited a strong defence response in shoots and roots, including increased expression of genes associated with plant responses, such as innate immunity, wounding, jasmonic acid pathway and chitinase activity. Strong induction of defence-associated genes in susceptible hop and a low number of infection-responsive genes in the roots of resistant hop are consistent with previous findings, confirming the pattern of excessive response of the susceptible cultivar, which ultimately fails to protect the plant from V. nonalfalfae. This research offers a multifaceted overview of transcriptional responses of susceptible and resistant hop cultivars to V. nonalfalfae infection and represents a valuable resource in the study of this plant

  9. Dynamics of verticillium species microsclerotia in field soils in response to fumigation, cropping patterns, and flooding.

    Science.gov (United States)

    Short, Dylan P G; Sandoya, German; Vallad, Gary E; Koike, Steven T; Xiao, Chang-Lin; Wu, Bo-Ming; Gurung, Suraj; Hayes, Ryan J; Subbarao, Krishna V

    2015-05-01

    Verticillium dahliae is a soilborne, economically significant fungal plant pathogen that persists in the soil for up to 14 years as melanized microsclerotia (ms). Similarly, V. longisporum is a very significant production constraint on members of the family Brassicaceae. Management of Verticillium wilt has relied on methods that reduce ms below crop-specific thresholds at which little or no disease develops. Methyl bromide, a broad-spectrum biocide, has been used as a preplant soil fumigant for over 50 years to reduce V. dahliae ms. However, reductions in the number of ms in the vertical and horizontal soil profiles and the rate at which soil recolonization occurs has not been studied. The dynamics of ms in soil before and after methyl bromide+chloropicrin fumigation were followed over 3 years in six 8-by-8-m sites in two fields. In separate fields, the dynamics of ms in the 60-cm-deep vertical soil profile pre- and postfumigation with methyl bromide+chloropicrin followed by various cropping patterns were studied over 4 years. Finally, ms densities were assessed in six 8-by-8-m sites in a separate field prior to and following a natural 6-week flood. Methyl bromide+chloripicrin significantly reduced but did not eliminate V. dahliae ms in either the vertical or horizontal soil profiles. In field studies, increases in ms were highly dependent upon the crop rotation pattern followed postfumigation. In the vertical soil profile, densities of ms were highest in the top 5 to 20 cm of soil but were consistently detected at 60-cm depths. Six weeks of natural flooding significantly reduced (on average, approximately 65% in the total viable counts of ms) but did not eliminate viable ms of V. longisporum.

  10. Whole genome wide expression profiles on germination of Verticillium dahliae microsclerotia.

    Directory of Open Access Journals (Sweden)

    Dongfang Hu

    Full Text Available Verticillium dahliae is a fungal pathogen causing Verticillium wilt on a range of economically important crops. Microsclerotia are its main survival and dormancy structures and serve as the primary inoculum on many hosts. Studies were conducted to determine the effect of temperature (5 to 50°C, pH (2 to 12 and nutrient regimes on microsclerotia germination. The optimal condition for microsclerotium germination was 20°C with pH 8.0 whereas nutrient regimes had no significant effect on its germination. The whole genome wide expression profiles during microsclerotium germination were characterized using the Illumina sequencing technology. Approximately 7.4 million of 21-nt cDNA tags were sequenced in the cDNA libraries derived from germinated and non-germinated microsclerotia. About 3.9% and 2.3% of the unique tags were up-regulated and down-regulated at least five-fold, respectively, in the germinated microsclerotia compared with the non-germinated microsclerotia. A total of 1654 genes showing differential expression were identified. Genes that are likely to have played important roles in microsclerotium germination include those encoding G-protein coupled receptor, lipase/esterase, cyclopentanone 1,2-monooxygenase, H(+/hexose cotransporter 1, fungal Zn(2-Cys(6 binuclear cluster domain, thymus-specific serine protease, glucan 1,3-beta-glucosidase, and alcohol dehydrogenase. These genes were mainly up-regulated or down-regulated only in germinated microsclerotia, compared with non-germinated microsclerotia. The differential expression of genes was confirmed by qRT-PCR analysis of 20 randomly selected genes from the 40 most differentially expressed genes.

  11. Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1.

    Science.gov (United States)

    Gaspar, Yolanda M; McKenna, James A; McGinness, Bruce S; Hinch, Jillian; Poon, Simon; Connelly, Angela A; Anderson, Marilyn A; Heath, Robyn L

    2014-04-01

    The plant defensin NaD1, from Nicotiana alata, has potent antifungal activity against a range of filamentous fungi including the two important cotton pathogens, Fusarium oxysporum f. sp. vasinfectum (Fov) and Verticillium dahliae. Transgenic cotton plants expressing NaD1 were produced and plants from three events were selected for further characterization. Homozygous plants were assessed in greenhouse bioassays for resistance to Fov. One line (D1) was selected for field trial testing over three growing seasons in soils naturally infested with Fov and over two seasons in soils naturally infested with V. dahliae. In the field trials with Fov-infested soil, line D1 had 2-3-times the survival rate, a higher tolerance to Fov (higher disease rank), and a 2-4-fold increase in lint yield compared to the non-transgenic Coker control. When transgenic line D1 was planted in V. dahliae-infested soil, plants had a higher tolerance to Verticillium wilt and up to a 2-fold increase in lint yield compared to the non-transgenic Coker control. Line D1 did not exhibit any detrimental agronomic features compared to the parent Coker control when plants were grown in non-diseased soil. This study demonstrated that the expression of NaD1 in transgenic cotton plants can provide substantial resistance to two economically important fungal pathogens.

  12. Colonization of resistant and susceptible lettuce cultivars by a green fluorescent protein-tagged isolate of Verticillium dahliae.

    Science.gov (United States)

    Vallad, G E; Subbarao, K V

    2008-08-01

    Interactions between lettuce and a green fluorescent protein (GFP)-expressing, race 1 isolate of Verticillium dahliae, were studied to determine infection and colonization of lettuce cultivars resistant and susceptible to Verticillium wilt. The roots of lettuce seedlings were inoculated with a conidial suspension of the GFP-expressing isolate. Colonization was studied with the aid of laser scanning confocal and epi-fluorescence microscopes. Few differences in the initial infection and colonization of lateral roots were observed between resistant and susceptible cultivars. Hyphal colonies formed on root tips and within the root elongation zones by 5 days, leading to the colonization of cortical tissues and penetration of vascular elements regardless of the lettuce cultivar by 2 weeks. By 8 to 10 weeks after inoculation, vascular discoloration developed within the taproot and crown regions of susceptible cultivars well in advance of V. dahliae colonization. Actual foliar wilt coincided with the colonization of the taproot and crown areas and the eruption of mycelia into surrounding cortical tissues. Advance colonization of stems, pedicels, and inflorescence, including developing capitula and mature achenes was observed. Seedborne infection was limited to the maternal tissues of the achene, including the pappus, pericarp, integument, and endosperm; but the embryo was never compromised. Resistant lettuce cultivars remained free of disease symptoms. Furthermore, V. dahliae colonization never progressed beyond infected lateral roots of resistant cultivars. Results indicated that resistance in lettuce may lie with the plant's ability to shed infected lateral roots or to inhibit the systemic progress of the fungus through vascular tissues into the taproot.

  13. Genomic Analysis of Verticillium Wilt Resistance and Drought Tolerance in Alfalfa

    Science.gov (United States)

    Alfalfa (Medicago sativa L.) is the fourth largest crop in the United States. Changing trends to multipurpose uses increases demand for alfalfa. However, the production of alfalfa is challenged by endemic and emerging diseases and adverse environmental factors. Identification of genes/loci controlli...

  14. Retarded development of Verticillium wilt in eggplant after application of Bion or Oryzalin

    NARCIS (Netherlands)

    Hijwegen, T.; Termorshuizen, A.J.

    2000-01-01

    Effects on root infection of eggplant caused by the soil-borne pathogen V. dahliae after application of the synthetic inducer Bion(R) or the herbicide Oryzalin(R) were investigated. Aerial application of 0.0125 and 0.025 mmol/l Bion(R) or 0.05 mmol/l Oryzalin(R) delayed disease development in Petri

  15. RNA silencing is required for Arabidopsis defence against Verticillium wilt disease

    NARCIS (Netherlands)

    Ellendorff, U.; Fradin, E.F.; Jonge, de R.; Thomma, B.P.H.J.

    2009-01-01

    RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently,

  16. Molecular determinants of resistance to Verticillium dahliae in potato

    Science.gov (United States)

    A constant evolutionary arms race between host resistance genes and pathogen effectors determine adaptive fitness. Therefore, identification of both host resistance genes and pathogen effectors is important in devising effective strategies to control disease. In tomato, resistance to Verticillium da...

  17. Soil suppressiveness towards Meloidogyne Verticillium or Pythium in greenhouse horticulture

    NARCIS (Netherlands)

    Wurff, van der A.W.G.; Slooten, van M.A.; Hamelink, R.; Bohne, S.; Wensveen, van W.

    2011-01-01

    Soils originating from fourteen greenhouse horticultural companies were assessed for the level of suppressiveness of three major pathogens of vegetables and flowers, namely the root knot nematode Meloidogyne incognita, Pythium aphanidermatum and Verticillium dahlia. As controls, three

  18. Vayg1 is required for microsclerotium formation and melanin production in Verticillium dahliae.

    Science.gov (United States)

    Fan, Rong; Klosterman, Steven J; Wang, Conghao; Subbarao, Krishna V; Xu, Xiangming; Shang, Wenjing; Hu, Xiaoping

    2017-01-01

    The fungus Verticillium dahliae causes vascular wilt disease on many plant species, including economically important crop and ornamental plants worldwide. It produces darkly pigmented resting structures known as microsclerotia, which are able to survive for up to 14years in soil, and represent one of the defining characteristics of this species. The pigment produced in V. dahliae is dihydroxynaphthalene (DHN)-melanin, a form of melanin common among fungi and named so for the intermediary of this melanin biosynthetic pathway. In this study, we characterized the function of the V. dahliae Vayg1 gene, whose homologs were involved in melanin biosynthesis in Exophiala dermatitidis (Wayg1) and Aspergillus fumigatus (Aayg1), by deletion and complementation of the gene and co-incubating deletion mutant with wild-type strain. Results showed that melanin production and microsclerotial formation in deletion mutants are inhibited. The Vayg1 deletion mutant also exhibited reduced pathogenicity. These results showed that Vayg1 is necessary for melanin and microsclerotium production, and we may thus hypothesize that the Vayg1 product may catalyze two different precursors, one of which is essential for DHN melanin production and the other one is involved in a signal network for microsclerotial formation in V. dahliae. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. The beneficial fungus Piriformospora indica protects Arabidopsis from Verticillium dahliae infection by downregulation plant defense responses.

    Science.gov (United States)

    Sun, Chao; Shao, Yongqi; Vahabi, Khabat; Lu, Jing; Bhattacharya, Samik; Dong, Sheqin; Yeh, Kai-Wun; Sherameti, Irena; Lou, Binggan; Baldwin, Ian T; Oelmüller, Ralf

    2014-10-09

    Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt symptoms in a wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years. Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes in the host. We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection. Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must participate in the regulation of the immune response against Vd.

  20. The transmission of oak wilt.

    Science.gov (United States)

    J.N. Gibbs; D.W. French

    1980-01-01

    Provides an up-to-date review of factors affecting the transmission of oak wilt, Ceratocystis fagacearum. Discusses the history and severity of the disease, the saprophytic existence of the fungus in the dying tree, seasonal susceptibility of trees to infection, overland and underground spread, the role of animals and insects as vectors or tree wounders, and the...

  1. Cotton Wilt and the Environment

    Indian Academy of Sciences (India)

    THE wilt disease of cotton (Fusarium sp.) has been studied extensively by Ajrekar and Bal (1921), Fahmy (1928), Kulkarni and Mundkur (1928),. Dastur (1929), Dharmarajulu (1932), Fikry (1932) and Kulkarni (1934). The last author has fully reviewed previous work. In these studies, detailed attention has been given, mainly, ...

  2. Characterization of a new partitivirus strain in Verticillium dahliae provides further evidence of the spread of the highly virulent defoliating pathotype through new introductions

    Directory of Open Access Journals (Sweden)

    Mari Carmen CAÑIZARES

    2015-12-01

    Full Text Available The soilborne pathogen Verticillium dahliae, causal agent of Verticillium wilt, has a worldwide distribution and many hosts of agronomic value. The worldwide spread of a highly virulent defoliating (D pathotype has greatly increased the threat posed by V. dahliae in olive trees. For effective disease management, it is important to know if the D pathotype is spreading long distances from contaminated material, or if D pathotype isolates may have originated locally from native V. dahliae populations several times. We identified a double-stranded RNA mycovirus in an olive D pathotype isolate from Turkey. Sequencing and phylogenetic analysis clustered the virus with members of the family Partitiviridae. The virus was most similar to a partitivirus previously identified in a V. dahliae isolate from cotton in China (VdPV1, with sequence identities of 94% and 91% at the nucleotide level for RNA1 and RNA2, respectively. The virus therefore corresponded to a strain of the established species, and we designated it VdPV1-ol (VdPV1 from olive. The identification of the same viral species in these two fungal isolates from geographically distant origins provides evidence of their relationships, supporting the hypothesis of long-distance movement of V. dahliae isolates.

  3. Identification of MiRNA from eggplant (Solanum melongena L. by small RNA deep sequencing and their response to Verticillium dahliae infection.

    Directory of Open Access Journals (Sweden)

    Liu Yang

    Full Text Available MiRNAs are a class of non-coding small RNAs that play important roles in the regulation of gene expression. Although plant miRNAs have been extensively studied in model systems, less is known in other plants with limited genome sequence data, including eggplant (Solanum melongena L.. To identify miRNAs in eggplant and their response to Verticillium dahliae infection, a fungal pathogen for which clear understanding of infection mechanisms and effective cure methods are currently lacking, we deep-sequenced two small RNA (sRNA libraries prepared from mock-infected and infected seedlings of eggplants. Specifically, 30,830,792 reads produced 7,716,328 unique miRNAs representing 99 known miRNA families that have been identified in other plant species. Two novel putative miRNAs were predicted with eggplant ESTs. The potential targets of the identified known and novel miRNAs were also predicted based on sequence homology search. It was observed that the length distribution of obtained sRNAs and the expression of 6 miRNA families were obviously different between the two libraries. These results provide a framework for further analysis of miRNAs and their role in regulating plant response to fungal infection and Verticillium wilt in particular.

  4. An endophytic Streptomyces sp. strain DHV3-2 from diseased root as a potential biocontrol agent against Verticillium dahliae and growth elicitor in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Cao, Peng; Liu, Chongxi; Sun, Pengyu; Fu, Xuepeng; Wang, Shaoxian; Wu, Fengzhi; Wang, Xiangjing

    2016-12-01

    Plant endophytes play important roles in biocontrol of plant diseases. Actinomycetes are used for biocontrol of fungal diseases caused by Verticillium dahliae. Many studies have focused on the endophytic actinomycetes isolated from the roots of healthy plants, but few on those from the roots of diseased plants. In the present research, actinomycetes were isolated from the roots of diseased and healthy tomato plants, respectively. The results showed that, in total, 86 endophytic actinomycetes were isolated for screening of their antimicrobial activities, 8 of which showed antagonism to V. dahliae in vitro. Among the 8 antagonistic strains, 5 (out of 36) were from the roots of diseased plants, with inhibition diameter zones ranging from 11.2 to 18.2 mm, whereas 3 (out of 50) were from the roots of healthy plants, with inhibition diameter zones ranging from 11.5 to 15.5 mm. Endophytic strain DHV3-2 was isolated from the root of a diseased plant and demonstrated a potent effect against V. dahliae and other pathogenic fungi by showing the largest inhibition diameter zones among all the eight antagonistic strains. Thus, strain DHV3-2 was chosen to investigate its biological control efficacies in vivo. Further study showed that the disease incidence and disease severity indices of tomato Verticillium wilt decreased significantly (P biocontrol agent against V. dahliae and growth elicitor in tomato.

  5. Ectopic expression of a Ve homolog VvVe gene from Vitis vinifera enhances defense response to Verticillium dahliae infection in tobacco.

    Science.gov (United States)

    Tang, Juan; Lin, Jing; Yang, Yuwen; Chen, Tianzi; Ling, Xitie; Zhang, Baolong; Chang, Youhong

    2016-01-15

    Verticillium wilt is a soil borne disease that can cause devastating losses to the production of many economically important crops. A Ve1 homologous gene responding to Verticillium dahliae infection was identified in Vitis vinifera cv. "HeiFeng" by semi-quantitative reverse transcription polymerase chain reaction and was designated as VvVe. The overexpression of VvVe in transgenic Nicotiana benthamiana plants significantly enhanced the resistance to isolate V991 of V. dahliae when compared with the wild type plants. The expressions of defense-related genes including the salicylic acid regulated gene pathogen-related 1 (PR1) but not PR2, the ethylene- and jasmonic acid-regulated genes ethylene response factor 1 (ERF1) and lipoxygenase (LOX) were significantly increased due to over expression of VvVe. And greater accumulation of active oxygen, callose and phenylalanine-ammonia lyase were observed in the leaves of transgenic VvVe tobacco plants than the wild type when under infection by V. dahliae. Moreover, the hypersensitive response mimicking cell death was exclusively occurred in the transgenic VvVe tobacco plants but not in the wild type. Taken together, the VvVe gene is a Ve1 like gene which involves in the signal cascade of salicylic acid, jasmonate, and ethylene defense pathways and enhances defense response to V. dahliae infection in the transgenic tobacco. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Colonization process of olive tissues by Verticillium dahliae and its in planta interaction with the biocontrol root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Prieto, Pilar; Navarro‐Raya, Carmen; Valverde‐Corredor, Antonio; Amyotte, Stefan G.; Dobinson, Katherine F.; Mercado‐Blanco, Jesús

    2009-01-01

    Summary The colonization process of Olea europaea by the defoliating pathotype of Verticillium dahliae, and the in planta interaction with the endophytic, biocontrol strain Pseudomonas fluorescens PICF7 were determined. Differential fluorescent protein tagging was used for the simultaneous visualization of P. fluorescens PICF7 and V. dahliae in olive tissues. Olive plants were bacterized with PICF7 and then transferred to V. dahliae‐infested soil. Monitoring olive colonization events by V. dahliae and its interaction with PICF7 was conducted using a non‐gnotobiotic system, confocal laser scanner microscopy and tissue vibratoming sections. A yellow fluorescently tagged V. dahliae derivative (VDAT‐36I) was obtained by Agrobacterium tumefaciens‐mediated transformation. Isolate VDAT‐36I quickly colonized olive root surface, successfully invaded root cortex and vascular tissues via macro‐ and micro‐breakages, and progressed to the aerial parts of the plant through xylem vessel cells. Strain PICF7 used root hairs as preferred penetration site, and once established on/in root tissues, hindered pathogen colonization. For the first time using this approach, the entire colonization process of a woody plant by V. dahliae is reported. Early and localized root surface and root endophytic colonization by P. fluorescens PICF7 is needed to impair full progress of verticillium wilt epidemics in olive. PMID:21255281

  7. Biological control of Rhizoctonia solani on potato by Verticillium ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-03

    Jun 3, 2009 ... sclerotia of R. solani was reduced by V. biguttatum isolates. V. biguttatum also significantly reduced the disease severity of R. solani on potato sprouts in pot experiments. This is the first report of V. biguttatum from sclerotia of R. solani in Turkey. Key words: Bio-control, potato, Rhizoctonia solani, Verticillium ...

  8. Biological control of Rhizoctonia solani on potato by Verticillium ...

    African Journals Online (AJOL)

    Ten isolates of Verticillium biguttatum were obtained from sclerotia of Rhizoctonia solani on potato tubers in Erzurum, Turkey. The interaction between V. biguttatum and R. solani was studied in vitro and in vivo. V. biguttatum isolates affected R. solani by antibiosis and parasitism. All isolates of V. biguttatum inhibited the ...

  9. Transcriptome profiling of Gossypium barbadense inoculated with Verticillium dahliae provides a resource for cotton improvement.

    Science.gov (United States)

    Zhang, Yan; Wang, Xing Fen; Ding, Ze Guo; Ma, Qing; Zhang, Gui Rong; Zhang, Shu Ling; Li, Zhi Kun; Wu, Li Qiang; Zhang, Gui Yin; Ma, Zhi Ying

    2013-09-22

    Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, is the most severe disease in cotton (Gossypium spp.), causing great lint losses worldwide. Disease management could be achieved in the field if genetically improved, resistant plants were used. However, the interaction between V. dahliae and cotton is a complicated process, and its molecular mechanism remains obscure. To understand better the defense response to this pathogen as a means for obtaining more tolerant cultivars, we monitored the transcriptome profiles of roots from resistant plants of G. barbadense cv. Pima90-53 that were challenged with V. dahliae. In all, 46,192 high-quality expressed sequence tags (ESTs) were generated from a full-length cDNA library of G. barbadense. They were clustered and assembled into 23126 unigenes that comprised 2661 contigs and 20465 singletons. Those unigenes were assigned Gene Ontology terms and mapped to 289 KEGG pathways. A total of 3027 unigenes were found to be homologous to known defense-related genes in other plants. They were assigned to the functional classification of plant-pathogen interactions, including disease defenses and signal transduction. The branch of "SA→NPR1→TGA→PR-1→Disease resistance" was first discovered in the interaction of cotton-V. dahliae, indicating that this wilt process includes both biotrophic and necrotrophic stages. In all, 4936 genes coding for putative transcription factors (TF) were identified in our library. The most abundant TF family was the NAC group (527), followed by G2-like (440), MYB (372), BHLH (331), bZIP (271) ERF, C3H, and WRKY. We also analyzed the expression of genes involved in pathogen-associated molecular pattern (PAMP) recognition, the activation of effector-triggered immunity, TFs, and hormone biosynthesis, as well as genes that are pathogenesis-related, or have roles in signaling/regulatory functions and cell wall modification. Their differential expression patterns were compared among

  10. Transcriptomic Analysis of Olea europaea L. Roots during the Verticillium dahliae Early Infection Process

    Directory of Open Access Journals (Sweden)

    Jaime Jiménez-Ruiz

    2017-03-01

    Full Text Available Olive cultivation is affected by a wide range of biotic constraints. Verticillium wilt of olive is one of the most devastating diseases affecting this woody crop, inflicting major economic losses in many areas, particularly within the Mediterranean Basin. Little is known about gene-expression changes during plant infection by of woody plants such as olive. A complete RNA-seq transcriptomic analysis of olive tree roots was made. Trinity assembler proved to be the best option to assemble the olive and transcriptomes. The olive transcriptome (Oleup consisted of 68,259 unigenes (254,252 isoforms/transcripts, and the transcriptome (Vedah consisted of 37,425 unigenes (52,119 isoforms/transcripts. Most unigenes of the Oleup transcriptome corresponded to cellular processes (12,339, metabolic processes (10,974, single-organism processes (7263, and responses to stimuli (5114. As for the Vedah transcriptome, most unigenes correspond to metabolic processes (25,372, cellular processes (23,718, localization (6385, and biological regulation (4801. Differential gene-expression analysis of both transcriptomes was made at 2 and 7 d post-infection. The induced genes of both organisms during the plant-pathogen interaction were clustered in six subclusters, depending on the expression patterns during the infection. Subclusters A to C correspond to plant genes, and subcluster D to F correspond to genes. A relevant finding was that the differentially expressed gene (DEGs included in subclusters B and C were highly enriched in proteolysis as well as protein-folding and biosynthesis genes. In addition, a reactive oxygen species (ROS defense was induced first in the pathogen and later in the plant roots.

  11. role of insects in the transmission of banana bacterial wilt

    African Journals Online (AJOL)

    through early ripening and rotting of fruits, and through wilting and ... stalk where insects always congregate exhibit the first wilt symptoms on ..... Yunna, China. Plant Systematics. and. Evolution 235:135-146. Ngambeki, D.S., Tushemereirwe, W. and Okasai,. P. 2006. Awareness of banana bacterial wilt by parish community ...

  12. Wilted cucumber plants infected by Fusarium oxysporum f. sp. cucumerinum do not suffer from water shortage.

    Science.gov (United States)

    Sun, Yuming; Wang, Min; Li, Yingrui; Gu, Zechen; Ling, Ning; Shen, Qirong; Guo, Shiwei

    2017-09-01

    Fusarium wilt is primarily a soil-borne disease and results in yield loss and quality decline in cucumber (Cucumis sativus). The main symptom of fusarium wilt is the wilting of entire plant, which could be caused by a fungal toxin(s) or blockage of water transport. To investigate whether this wilt arises from water shortage, the physiological responses of hydroponically grown cucumber plants subjected to water stress using polyethylene glycol (PEG, 6000) were compared with those of plants infected with Fusarium oxysporum f. sp. cucumerinum (FOC). Parameters reflecting plant water status were measured 8d after the start of treatment. Leaf gas exchange parameters and temperature were measured with a LI-COR portable open photosynthesis system and by thermal imaging. Chlorophyll fluorescence and chloroplast structures were assessed by imaging pulse amplitude-modulated fluorometry and transmission electron microscopy, respectively. Cucumber water balance was altered after FOC infection, with decreased water absorption and hydraulic conductivity. However, the responses of cucumber leaves to FOC and PEG differed in leaf regions. Under water stress, measures of lipid peroxidation (malondialdehyde) and chlorophyll fluorescence indicated that the leaf edge was more seriously injured, with a higher leaf temperature and disrupted leaf water status compared with the centre. Here, abscisic acid (ABA) and proline were negatively correlated with water potential. In contrast, under FOC infection, membrane damage and a higher temperature were observed in the leaf centre while ABA and proline did not vary with water potential. Cytologically, FOC-infected cucumber leaves exhibited circular chloroplasts and swelled starch grains in the leaf centre, in which they again differed from PEG-stressed cucumber leaves. This study illustrates the non-causal relationship between fusarium wilt and water transport blockage. Although leaf wilt occurred in both water stress and FOC infection, the

  13. The Vascular Pathogen Verticillium longisporum Does Not Affect Water Relations and Plant Responses to Drought Stress of Its Host, Brassica napus.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-04-01

    Verticillium longisporum is a host-specific vascular pathogen of oilseed rape (Brassica napus L.) that causes economic crop losses by impairing plant growth and inducing premature senescence. This study investigates whether plant damage through Verticillium stem striping is due to impaired plant water relations, whether V. longisporum affects responses of a susceptible B. napus variety to drought stress, and whether drought stress, in turn, affects plant responses to V. longisporum. Two-factorial experiments on a susceptible cultivar of B. napus infected or noninfected with V. longisporum and exposed to three watering levels (30, 60, and 100% field capacity) revealed that drought stress and V. longisporum impaired plant growth by entirely different mechanisms. Although both stresses similarly affected plant growth parameters (plant height, hypocotyl diameter, and shoot and root dry matter), infection of B. napus with V. longisporum did not affect any drought-related physiological or molecular genetic plant parameters, including transpiration rate, stomatal conductance, photosynthesis rate, water use efficiency, relative leaf water content, leaf proline content, or the expression of drought-responsive genes. Thus, this study provides comprehensive physiological and molecular genetic evidence explaining the lack of wilt symptoms in B. napus infected with V. longisporum. Likewise, drought tolerance of B. napus was unaffected by V. longisporum, as was the level of disease by drought conditions, thus excluding a concerted action of both stresses in the field. Although it is evident that drought and vascular infection with V. longisporum impair plant growth by different mechanisms, it remains to be determined by which other factors V. longisporum causes crop loss.

  14. Proteomic and Virus-induced Gene Silencing (VIGS) Analyses Reveal That Gossypol, Brassinosteroids, and Jasmonic acid Contribute to the Resistance of Cotton to Verticillium dahliae *

    Science.gov (United States)

    Gao, Wei; Long, Lu; Zhu, Long-Fu; Xu, Li; Gao, Wen-Hui; Sun, Long-Qing; Liu, Lin-Lin; Zhang, Xian-Long

    2013-01-01

    Verticillium wilt causes massive annual losses of cotton yield, but the mechanism of cotton resistance to Verticillium dahliae is complex and poorly understood. In this study, a comparative proteomic analysis was performed in resistant cotton (Gossypium barbadense cv7124) on infection with V. dahliae. A total of 188 differentially expressed proteins were identified by mass spectrometry (MALDI-TOF/TOF) analysis and could be classified into 17 biological processes based on Gene Ontology annotation. Most of these proteins were implicated in stimulus response, cellular processes and metabolic processes. Based on the proteomic analysis, several genes involved in secondary metabolism, reactive oxygen burst and phytohormone signaling pathways were identified for further physiological and molecular analysis. The roles of the corresponding genes were further characterized by employing virus-induced gene silencing (VIGS). Based on the results, we suggest that the production of gossypol is sufficient to affect the cotton resistance to V. dahliae. Silencing of GbCAD1, a key enzyme involving in gossypol biosynthesis, compromised cotton resistance to V. dahliae. Reactive oxygen species and salicylic acid signaling may be also implicated as regulators in cotton responsive to V. dahliae according to the analysis of GbSSI2, an important regulator in the crosstalk between salicylic acid and jasmonic acid signal pathways. Moreover, brassinosteroids and jasmonic acid signaling may play essential roles in the cotton disease resistance to V. dahliae. The brassinosteroids signaling was activated in cotton on inoculation with V. dahliae and the disease resistance of cotton was enhanced after exogenous application of brassinolide. Meanwhile, jasmonic acid signaling was also activated in cotton after inoculation with V. dahliae and brassinolide application. These data provide highlights in the molecular basis of cotton resistance to V. dahliae. PMID:24019146

  15. Proteomic and virus-induced gene silencing (VIGS) Analyses reveal that gossypol, brassinosteroids, and jasmonic acid contribute to the resistance of cotton to Verticillium dahliae.

    Science.gov (United States)

    Gao, Wei; Long, Lu; Zhu, Long-Fu; Xu, Li; Gao, Wen-Hui; Sun, Long-Qing; Liu, Lin-Lin; Zhang, Xian-Long

    2013-12-01

    Verticillium wilt causes massive annual losses of cotton yield, but the mechanism of cotton resistance to Verticillium dahliae is complex and poorly understood. In this study, a comparative proteomic analysis was performed in resistant cotton (Gossypium barbadense cv7124) on infection with V. dahliae. A total of 188 differentially expressed proteins were identified by mass spectrometry (MALDI-TOF/TOF) analysis and could be classified into 17 biological processes based on Gene Ontology annotation. Most of these proteins were implicated in stimulus response, cellular processes and metabolic processes. Based on the proteomic analysis, several genes involved in secondary metabolism, reactive oxygen burst and phytohormone signaling pathways were identified for further physiological and molecular analysis. The roles of the corresponding genes were further characterized by employing virus-induced gene silencing (VIGS). Based on the results, we suggest that the production of gossypol is sufficient to affect the cotton resistance to V. dahliae. Silencing of GbCAD1, a key enzyme involving in gossypol biosynthesis, compromised cotton resistance to V. dahliae. Reactive oxygen species and salicylic acid signaling may be also implicated as regulators in cotton responsive to V. dahliae according to the analysis of GbSSI2, an important regulator in the crosstalk between salicylic acid and jasmonic acid signal pathways. Moreover, brassinosteroids and jasmonic acid signaling may play essential roles in the cotton disease resistance to V. dahliae. The brassinosteroids signaling was activated in cotton on inoculation with V. dahliae and the disease resistance of cotton was enhanced after exogenous application of brassinolide. Meanwhile, jasmonic acid signaling was also activated in cotton after inoculation with V. dahliae and brassinolide application. These data provide highlights in the molecular basis of cotton resistance to V. dahliae.

  16. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    Science.gov (United States)

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Broad taxonomic characterization of Verticillium wilt resistance genes reveals an ancient origin of the tomato Ve1 immune receptor

    NARCIS (Netherlands)

    Song, Yin; Zhang, Zhao; Seidl, Michael F.; Majer, Aljaz; Jakse, Jernej; Javornik, Branka; Thomma, Bart P.H.J.

    2017-01-01

    Plant-pathogenic microbes secrete effector molecules to establish themselves on their hosts, whereas plants use immune receptors to try and intercept such effectors in order to prevent pathogen colonization. The tomato cell surface-localized receptor Ve1 confers race-specific resistance against

  18. Activation of defence responses on cocoa against Verticillium wilt by natural extracts and acibenzolar-S-methyl

    OpenAIRE

    Pereira, Ricardo Borges; Resende, Mário Lúcio Vilela de; Ribeiro Júnior, Pedro Martins; Amaral, Daniel Rufino; Lucas, Gilvaine Ciavareli; Cavalcanti, Fábio Rossi

    2008-01-01

    O objetivo deste trabalho foi avaliar o potencial de extratos fúngicos e vegetais na redução da murcha-de-verticílio do cacaueiro, as atividades da peroxidase e polifenoloxidase e o conteúdo de lignina. Mudas de cacaueiro foram pulverizadas com filtrado de micélio de Rhizopus sp. (FMR), quitosana de Rhizopus sp. (QMR) e Trichoderma sp. (QMT), extratos de casca in natura e seca de maracujá, extrato metanólico de casca seca de frutos de maracujá (MMS) e acibenzolar-S-metil (ASM - 0.2 mg mL-1) e...

  19. Nachweis von Verticillium dahliae an Pfefferminze (Mentha x piperita L.

    Directory of Open Access Journals (Sweden)

    Gärber, Ute

    2014-09-01

    Full Text Available In Beständen von Pfefferminze wurden Krankheitssymptome beobachtet, die sich in Wuchshemmungen, Stängelverbräunungen, Blattchlorosen und Welke zeigten. Teilweise starben die Pflanzen bzw. einzelne Triebe ab. Als Ursache konnte Verticillium dahliae nachgewiesen werden. In einem Infektionsversuch im Gewächshaus wurden sieben Wochen alte Pfefferminzpflanzen der Sorte Multimentha durch Angießen mit einer Konidiensuspension (106 Konidien/ml Suspension inokuliert. Erste Krankheitssymptome erschienen acht Wochen nach Inokulation. Innerhalb kurzer Zeit nahm der Befall stark zu. Aus den kranken Pflanzenteilen wie Stängel und Blatt konnte der Erreger reisoliert werden.

  20. Recovery Plan for Laurel Wilt of Avocado

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial avocado production in Florida, as well as the National Germplasm Repository for avocado in Miami (USDA-ARS). Elsewhere in the US, major (California) and minor comm...

  1. Restricted spread of tomato spotted wilt virus

    NARCIS (Netherlands)

    Maris, P.C.; Joosten, N.N.; Goldbach, R.W.; Peters, D.

    2003-01-01

    Spread of Tomato spotted wilt virus (TSWV) and population development of its vector Frankliniella occidentalis were studied on the pepper accessions CPRO-1 and Pikante Reuzen, which are resistant and susceptible to thrips, respectively. Viruliferous thrips were released on plants of each accession

  2. Musa balbisiana resists Xanthomonas wilt disease through ...

    African Journals Online (AJOL)

    Musa balbisiana resists Xanthomonas wilt disease through interfering with the multiplication of Xanthomonas vasicola pv musacearum coupled with whole organ (leaf) ... The pathogen population within plant tissues was observed to drop in a 50 mg tissue from 3.06x107cfu at 18days after inoculation in the inoculated leaf to ...

  3. Bestrijding van Verticillium in de bodem : in de teelt van laanbomen (klei) en rozen (zand)

    NARCIS (Netherlands)

    Hiemstra, J.A.; Sluis, van der B.J.

    2014-01-01

    1 Samenvatting en conclusies De in dit rapport beschreven experimenten werden opgezet om een aantal nieuwe methoden (alternatieven voor chemische bodemontsmetting) te testen op hun werkzaamheid voor wat betreft bestrijding van Verticillium dahliae (Vd) en daarnaast ook nematoden (Pratylenchus

  4. Maintenance of sex-related genes and the co-occurrence of both mating types in Verticillium dahliae.

    Directory of Open Access Journals (Sweden)

    Dylan P G Short

    Full Text Available Verticillium dahliae is a cosmopolitan, soilborne fungus that causes a significant wilt disease on a wide variety of plant hosts including economically important crops, ornamentals, and timber species. Clonal expansion through asexual reproduction plays a vital role in recurring plant epidemics caused by this pathogen. The recent discovery of recombination between clonal lineages and preliminary investigations of the meiotic gene inventory of V. dahliae suggest that cryptic sex appears to be rare in this species. Here we expanded on previous findings on the sexual nature of V. dahliae. Only 1% of isolates in a global collection of 1120 phytopathogenic V. dahliae isolates contained the MAT1-1 idiomorph, whereas 99% contained MAT1-2. Nine unique multilocus microsatellite types comprised isolates of both mating types, eight of which were collected from the same substrate at the same time. Orthologs of 88 previously characterized sex-related genes from fungal model systems in the Ascoymycota were identified in the genome of V. dahliae, out of 93 genes investigated. Results of RT-PCR experiments using both mating types revealed that 10 arbitrarily chosen sex-related genes, including MAT1-1-1 and MAT1-2-1, were constitutively expressed in V. dahliae cultures grown under laboratory conditions. Ratios of non-synonymous (amino-acid altering to synonymous (silent substitutions in V. dahliae MAT1-1-1 and MAT1-2-1 sequences were indistinguishable from the ratios observed in the MAT genes of sexual fungi in the Pezizomycotina. Patterns consistent with strong purifying selection were also observed in 18 other arbitrarily chosen V. dahliae sex-related genes, relative to the patterns in orthologs from fungi with known sexual stages. This study builds upon recent findings from other laboratories and mounts further evidence for an ancestral or cryptic sexual stage in V. dahliae.

  5. Resistance to Fusarium wilt in common bean

    Directory of Open Access Journals (Sweden)

    Renata Oliveira Batista

    2016-09-01

    Full Text Available In breeding programs, understanding the potential of parents should be a way to spend significantly less time and costs to obtain new cultivars. For this, the objective of this study was to estimate the general and specific combining ability of parents aiming common bean breeding for resistance to Fusarium wilt (FW based on disease severity and reduction in plant growth. Eight common bean genotypes were crossed in a 3 x 5 partial diallel mating scheme to obtain F1 hybrids. The parents and their 15 F1 hybrids were evaluated for severity of Fusarium wilt, area under the disease progress curve, percentage of plant height reduction and plant shoot fresh weight reduction and grain yield. The resistance of common bean to FW is controlled by a few dominant genes. The reduction in plant growth is controlled by a different set of genes that can increase the selection efficiency of parents for common bean breeding.

  6. Resistance to Fusarium wilt in common bean

    OpenAIRE

    Renata Oliveira Batista; Oliveira, Ana Maria Cruz e; Johnn Lennon Oliveira Silva; Alessandro Nicoli; Pedro Crescêncio Sousa Carneiro; José Eustáquio de Sousa Carneiro; Trazilbo José de Paula Júnior; Marisa Vieira de Queiroz

    2016-01-01

    Abstract In breeding programs, understanding the potential of parents should be a way to spend significantly less time and costs to obtain new cultivars. For this, the objective of this study was to estimate the general and specific combining ability of parents aiming common bean breeding for resistance to Fusarium wilt (FW) based on disease severity and reduction in plant growth. Eight common bean genotypes were crossed in a 3 x 5 partial diallel mating scheme to obtain F1 hybrids. The paren...

  7. Integrated management strategies for tomato Fusarium wilt.

    Science.gov (United States)

    Ajilogba, Caroline F; Babalola, Olubukola O

    2013-01-01

    Fusarium wilt is caused by the fungal pathogens, Fusarium oxysporum or Fusarium solani. It is a devastating disease that affects many important food and vegetable crops and a major source of loss to farmers worldwide. Initial strategies developed to combat this devastating plant disease include the use of cultural, physical and chemical control. None of these strategies have been able to give the best results of completely ameliorating the situation except for the cultural method which is mainly preventive. A good knowledge of the nature, behaviour and environmental conditions of growth of the disease agent is very important to controlling the disease development in that case. Biological control has been shown to be an environmentally friendly alternative. It makes use of rhizospheric and endophytic microorganisms that can survive and compete favourably well with the Fusarium wilt pathogen. They include plant growth-promoting rhizobacteria (PGPR) such as Bacillus spp. and Pseudomonas spp. For PGPR to control or inhibit the growth of the Fusarium wilt pathogen, they make use of mechanisms such as indole acetic acid production, siderophore production, phosphate solublilization, systemic resistance induction and antifungal volatile production among others.

  8. ANTAGONISMO IN VITRO DE Trichoderma spp. A Verticillium dahliae KLEB

    Directory of Open Access Journals (Sweden)

    M.P. MARTINS-CORDER

    1998-01-01

    Full Text Available O presente trabalho visou testar e selecionar isolados selvagens de Trichoderma spp. quanto à capacidade antagônica ao fungo fitopatogênico Verticillium dahliae. Os ensaios in vitro consistiram de testes para avaliar a capacidade hiperparasítica e de antibiose através da produção de metabólitos voláteis e não voláteis. Pela técnica de culturas pareadas, 47 isolados de diversas espécies de Trichoderma foram avaliados e, pelos resultados obtidos, 20 foram selecionados. Através do teste de antibiose, selecionaram-se 7 isolados: T15P e Tal-1 (T. viride, TW6 e CNP311A (T. koningii, CNP17 e TCII (T. harzianum e Tal-10 (T. aureoviride os quais inibiram completamente o crescimento micelial de V. dahliae através da produção de metabólitos. Observações microscópicas demonstraram interações de hifas entre Trichoderma sp. e V. dahliae, tais como: enrolamento, crescimento paralelo de ambos, formação de ganchos.This work was carried out to test and to select wild strains of Trichoderma spp. with antagonistic ability against Verticillium dahliae. The in vitro assay consisted of the antibiosis technique by assessment of volatile and non-volatile metabilites and hyphal interaction. Forty seven Trichoderma strains were evaluated and twenty strains were selected by their antagonistic ability against V. dahliae. Through the antibiosis test, seven strains of different species T15P and Tal-1 (T. viride; TW6 and CNP311A (T. koningii; CNP17 and TCII (T. harzianum and Tal-10 (T. aureoviride inhibited the mycelial growth of V. dahliae due to the production of metabolites. Several kinds of hyphal interference were observed such as coiling and hook formation.

  9. Identification and Differentiation of Verticillium Species and V. longisporum Lineages by Simplex and Multiplex PCR Assays

    Science.gov (United States)

    Inderbitzin, Patrik; Davis, R. Michael; Bostock, Richard M.; Subbarao, Krishna V.

    2013-01-01

    Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae), a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex) PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex) PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers. PMID:23823707

  10. Identification and Differentiation of Verticillium Species and V. longisporum Lineages by Simplex and Multiplex PCR Assays.

    Directory of Open Access Journals (Sweden)

    Patrik Inderbitzin

    Full Text Available Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae, a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers.

  11. Effect of the fungicide Prochloraz-Mn on the cell wall structure of Verticillium fungicola.

    Science.gov (United States)

    Bernardo, D; Novaes-Ledieu, M; Perez Cabo, A; Gea Alegría, F J; García Mendoza, C

    2002-09-01

    The chemical structure of the cell wall of two isolates of Verticillium fungicolacollected from diseased fruit bodies of the commercial mushroom Agaricus bisporus treated with the fungicide Prochloraz-Mn was analyzed. The isolates were obtained during different periods of time and grown in the absence and presence of the LD(50) values of the fungicide for V. fungicola. In addition, another V. fungicola isolate collected previous to the routine utilization of Prochloraz-Mn but grown under the same conditions was also analyzed. The overall chemical composition of the cell wall from the three isolates showed detectable differences in their basic components, with a significant decrease in the protein content in fungicide-treated cells. This inhibitory effect was partially compensated by an increase in neutral and/or aminated carbohydrates and was accompanied by appreciable modifications of polysaccharide structure, as deduced after methylation analysis and gas-liquid chromatography-mass spectrometry (GLC-MS). Moreover, differences in hyphal morphology caused by the fungicide were observed by transmission electron microscopy (TEM).

  12. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    Science.gov (United States)

    Verticillium dahliae (Vd) and Verticillium albo-atrum (Va) are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating geneti...

  13. Oak Wilt: People and Trees, A Community Approach to Management

    Science.gov (United States)

    J. Juzwik; S. Cook; L. Haugen; J. Elwell

    2004-01-01

    Version 1.3. This self-paced short course on CD-ROM was designed as a learning tool for urban and community foresters, city administrators, tree inspectors, parks and recreation staff, and others involved in oak wilt management.Click the "View or print this publication" link below to request your Oak Wilt: People and...

  14. Effect of selected essential oil plants on bacterial wilt disease ...

    African Journals Online (AJOL)

    SARAH

    2014-03-25

    Mar 25, 2014 ... ABSTRACT. Objective: Bacterial wilt disease caused by Ralstonia solanacearum is a major constrain to production of potatoes (Solanum tuberosum). Control of bacterial wilt is very difficult as there are no effective curative chemicals. This study was aimed at investigating the potential roles of essential oil ...

  15. How to identify and manage oak wilt in Texas

    Science.gov (United States)

    D.N. Appel; R.S. Cameron; A.D. Wilson; J.D. Johnson

    2008-01-01

    Transporting unseasoned firewood from diseased red oaks is a potential means of spreading the oak wilt fungus. Oak wilt cannot be transmitted by burning infected firewood, but fungal mats may form on firewood in storage. Presently, no vectors have been proven to transmit the fungus from live oaks to other oak trees, but diseased wood fromany oak species should never be...

  16. Ambrosia beetles associated with laurel wilt of avocado

    Science.gov (United States)

    Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of trees in the family Lauraceae. Laurel wilt has since spr...

  17. Fermentative attributes of wilted vs. unwilted Digitaria eriantha silage

    African Journals Online (AJOL)

    The ammonia nitrogen (NH3-N) as percentage of total nitrogen (N) was higher in unwilted silage than prior wilted silage without molasses, while in the presence of molasses the effect of wilting on NH3-N as percentage of total N was not significant. Keywords: Silage, fermentation process, moisture level, Digitaria eriantha, ...

  18. Fusarium verticillioides: A new cotton wilt pathogen in Uzbekistan

    Science.gov (United States)

    An increase in wilt has been observed in cotton fields in Uzbekistan. This prompted us to conduct a survey of Uzbek cotton fields for wilt over a five year period beginning in 2007. Twenty-four regions with different soil types and ecologies were screened. In 9 regions, over 45% of the plants dem...

  19. Simultaneous laurel wilt disease biology and resistance research

    Science.gov (United States)

    Jason A. Smith; Randy C. Ploetz

    2012-01-01

    Laurel wilt (LW) is a devastating, emerging disease of native and non-native members of the Lauraceae family in the southeastern United States. Currently, the fungal pathogen (Raffaelea lauricola) and its vector (Xyleborus glabratus) are found in Alabama, Florida, Georgia, Mississippi, and North and South Carolina. The wilt is...

  20. Effect of selected essential oil plants on bacterial wilt disease ...

    African Journals Online (AJOL)

    Objective: Bacterial wilt disease caused by Ralstonia solanacearum is a major constrain to production of potatoes (Solanum tuberosum). Control of bacterial wilt is very difficult as there are no effective curative chemicals. This study was aimed at investigating the potential roles of essential oil plants in control of the disease.

  1. Strategies for resistance to bacterial wilt disease of bananas through ...

    African Journals Online (AJOL)

    The transgenic approach shows potential for the genetic improvement of the crop using a wide set of transgenes currently available which may confer bacterial resistance. This article discusses the potential strategies to develop transgenic banana plants resistant to bacterial wilt disease. Key Words: Banana, bacterial wilt, ...

  2. Biocontrol of potato wilt by selective rhizospheric and endophytic ...

    African Journals Online (AJOL)

    Biocontrol of potato wilt by selective rhizospheric and endophytic bacteria associated with potato plant. ... identification with the Ralstonia solanacearum specific primers 759/760 revealed that 24 of the pathogenic isolates belong to the Ralstonia solanacearum species, biovar two; the causal agent of potato bacterial wilt.

  3. Inheritance and identification of SCAR marker linked to bacterial wilt ...

    African Journals Online (AJOL)

    In the present work, the combinations (F1) were crossed between highly resistant and susceptible to bacterial wilt eggplant parents and its F2, BC1 segregation population plants were inoculated with race1 of Ralstonia solanacearum in greenhouse. In this paper, we reported that the inheritance of bacterial wilt resistance in ...

  4. Entomopathogenic Potential of Verticillium and Acremonium Species (Deuteromycotina: Hyphomycetes)

    DEFF Research Database (Denmark)

    Steenberg, Tove; Humber, Richard A

    1999-01-01

    Hyphomycetes with conidia formed in slimy heads from hyaline mycelium were isolated from a range of insect hosts. Isolation on artificial medium and microscopic examination revealed that these fungi in many cases mere not Verticillium lecanii despite a superficial resemblance to this common...... entomopathogen. The fungi were identified as Verticillium fusisporum, Veritcillium psalliotae, Verticillium lamellicola, and species of Acremonium. Isolates of these fungi were bioassayed against the sweet-potato whitefly (Bemisia tabaci) and against the housefly (Musca domestica) to examine...... their entomopathogenicity. A test was also conducted with a coleopteran (lesser mealworm, Alphitobius diaperinus) to further evaluate the host range for some of the fungi. V. lamellicola was not pathogenic to the two species of insects treated, while varying levels of pathogenicity were shown for the other species...

  5. Island cotton Enhanced Disease Susceptibility 1 gene encoding a lipase-like protein plays a crucial role in response to Verticillium dahliae by regulating the SA level and H2O2 accumulation

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2016-12-01

    Full Text Available Cotton is one of the most economically important crops, but most cultivated varieties lack adequate innate immunity or resistance to Verticillium wilt. This results in serious losses to both yield and fiber quality. To identify the genetic resources for innate immunity and understand the pathways for pathogen defenses in this crop, here we focus on orthologs of the central Arabidopsis thaliana defense regulator Enhanced Disease Susceptibility 1 (EDS1. The full-length cDNA of GbEDS1 was obtained by screening the full-length cDNA library of Gossypium barbadense combining with RACE strategy. Its open reading frame is 1848 bp long, encoding 615 amino acid residues. Sequence analysis showed that GbEDS1 contains a conserved N-terminal lipase domain and an EDS1-specific KNEDT motif. Expression profiling indicated that the gene is induced by Verticillium dahliae as well as salicylic acid (SA treatment. Subcellular localization assays revealed that GbEDS1 is located in the cell cytoplasm and nucleus. Overexpression of GbEDS1 in Arabidopsis dramatically up-regulated SA and H2O2 production, resulting in enhanced disease resistance to V. dahliae. Silencing of GbEDS1 in G. barbadense significantly decreased SA and H2O2 acumulation, leading to the cotton more susceptibility. Moreover, combining the gene expression results from transgenic Arabidopsis and silenced-GbEDS1 cotton, it indicated that GbEDS1 could activate GbNDR1 and GbBAK1 expression. These findings not only broaden our knowledge about the biological role of GbEDS1, but also provide new insights into the defense mechanisms of GbEDS1 against V. dahliae in cotton.

  6. Distribution and persistence of Verticillium dahliae in the xylem of Norway maple and European ash trees

    NARCIS (Netherlands)

    Keykha Saber, Mojtaba; Thomma, Bart P.H.J.; Hiemstra, Jelle A.

    2018-01-01

    Verticillium dahliae colonizes the xylem vessels of susceptible host plants. Hence it can be expected that the distribution of the fungus as well as disease progress will be influenced by the anatomy of the xylem of that host. Here, we studied the spatial and temporal distribution of V. dahliae in

  7. Analysis of a MULE-cyanide hydratase gene fusion in Verticillium dahliae

    Science.gov (United States)

    The genome of the phytopathogenic fungus Verticillium dahliae encodes numerous Class II “cut-and-paste” transposable elements, including those of a small group of MULE transposons. We have previously identified a fusion event between a MULE transposon sequence and sequence encoding a cyanide hydrata...

  8. Optimization of Verticillium lecanii spore production in solid-state fermentation on sugarcane bagasse

    NARCIS (Netherlands)

    Shi, Y.; Xu, X.; Zhu, Y.

    2009-01-01

    Verticillium lecanii is an entomopathogen with high potential in biological control of pests. We developed a solid-state fermentation with sugarcane bagasse as carrier absorbing liquid medium to propagate V. lecanii spores. Using statistical experimental design, we optimized the medium composition

  9. Quantification of microsclerotia of Verticillium dahliae in plant material by image analysis

    NARCIS (Netherlands)

    Mol, L.; Meijer, E.M.J.

    1995-01-01

    A procedure for the quantification of microsclerotia ofVerticillium dahliae with an image analysis system was compared with counting by eye. Colonised potato plant material was used from plants grown in pathogen-free soil in a greenhouse and from twelve crops (including four potato cultivars) grown

  10. Generation and characterization of mutants of tomato spotted wilt virus

    NARCIS (Netherlands)

    Oliveira Resende, de R.

    1993-01-01

    In nature, tospoviruses like tomato spotted wilt virus (TSWV) are exclusively transmitted by thrips species (Sakimura, 1962) producing numerous enveloped virions during infection, which accumulate in the cisternae of the endoplasmatic. reticulum. system (Kitajima, 1965; Milne, 1970; Ie,

  11. Inheritance and identification of SCAR marker linked to bacterial wilt ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... Key word: Eggplant, bacterial wilt-resistance, molecular marker, inheritance. ... hundreds of plant species, including many crops such as tomato, potato ... rotation, adjusting the date of planting, cultural methods and soil ...

  12. Effect of selected essential oil plants on bacterial wilt disease ...

    African Journals Online (AJOL)

    SARAH

    2014-03-25

    Sage brush), Ocimum suave (Cambodia) and Tarchonanthus camphorates .... Statistical analysis was performed with the GenStat 12.1 (PC/Windows XP) while mean wilt incidences were compared using Fisher's least significant ...

  13. The effects of wilting, molasses and inoculants on the fermentation ...

    African Journals Online (AJOL)

    The objective was to determine the effects of wilting, molasses and inoculants on the biochemistry and in vitro and in situ digestion of lucerne silage. Lucerne containing 200 g/kg of dry matter (DM) was ensiled as fresh or wilted (370 g/kg DM). Molasses, at application rates of 0, 50 and 100 g molasses/kg DM, was added to ...

  14. Inactivation of sclerotia of Rhizoctonia solani on potato tubers by Verticillium biguttatum, a soil-borne mycoparasite

    NARCIS (Netherlands)

    Jager, G.; Velvis, H.

    1988-01-01

    Experiments in the laboratory and on farms with potato tubers in storages are described in which sclerotia of Rhizoctonia solani were inactivated after inoculation of infected tubers with a suspension of conidia and hyphal fragments of Verticillium biguttatum

  15. Transcription factor VdCmr1 is required for pigment production, protection from UV irradiation, and regulates expression of melanin biosynthetic genes in Verticillium dahliae.

    Science.gov (United States)

    Wang, Yonglin; Hu, Xiaoping; Fang, Yulin; Anchieta, Amy; Goldman, Polly H; Hernandez, Gustavo; Klosterman, Steven J

    2018-02-27

    Verticillium dahliae is a soilborne fungus that causes vascular wilt diseases on numerous plant species worldwide. The production of darkly melanized microsclerotia is crucial in the disease cycle of V. dahliae, as these structures allow for long-term survival in soil. Previously, transcriptomic and genomic analysis identified a cluster of genes in V. dahliae that encodes some dihydroxynaphthalene (DHN) melanin biosynthetic pathway homologues found in related fungi. In this study, we explored the roles of cluster-specific transcription factor VdCmr1, as well as two other genes within the cluster encoding a polyketide synthase (VdPKS1) and a laccase (VdLac1), enzymes at initial and endpoint steps in DHN melanin production. The results revealed that VdCmr1 and VdPKS1 are required for melanin production, but neither is required for microsclerotia production. None of the three genes were required for pathogenesis on tobacco and lettuce. Exposure of ΔVdCmr1 and wild-type strains to UV irradiation, or to high temperature (40 °C), revealed an approx. 50 % reduction of survival in the ΔVdCmr1 strain, relative to the wild-type strain, in response to either condition. Expression profiles revealed that expression of some melanin biosynthetic genes are in part dependent on VdCmr1. Combined data indicate VdCmr1 is a key regulator of melanin biosynthesis, and that via regulation of melanogenesis, VdCmr1 affects survival of V. dahliae in response to abiotic threats. We conclude with a model showing regulation of VdCmr1 by a high osmolarity glycerol response (Hog)-type MAP kinase pathway.

  16. Biological control of Rhizoctonia solani in potato by antagonists : field testing of the effect of inoculation of seed tubers with Verticillium biguttatum and other antagonists in 1981 and 1982

    NARCIS (Netherlands)

    Jager, G.; Velvis, H.

    1983-01-01

    Onderzoek naar de biologische bestrijding van Rhizoctonia solani in aardappelen op verschillende grondsoorten (klei, zavel en zand) door middel van inoculatie van de poters met de schimmel Verticillium biguttatum en andere antagonisten, inklusief Azotobacter chroococcum. Verticillium biguttatum gaf

  17. Primeiro relato do Tomato spotted wilt virus (TSWV em Campanula medium L. no Brasil First report of Tomato spotted wilt virus (TSWV infecting Campanula medium in Brazil

    Directory of Open Access Journals (Sweden)

    Ricardo Gioria

    2010-06-01

    Full Text Available Plantas de campânula (Campanula medium exibindo mosaico e necrose foliar e anéis em flores foram coletadas em uma estufa comercial de flores na região de Atibaia, SP. Suspeitando de possível etiologia viral, amostras de tecido lesionado foram analisadas por ensaios de transmissão mecânica, microscopia eletrônica e sorologia. Todos os resultados apontaram para a presença do Tomato spotted wilt virus (TSWV como o responsável pelos sintomas. Esse é o primeiro relato deste patógeno em campânula no Brasil.Plants of bellflower (Campanula medium exhibiting symptoms of mosaic, leaf necrosis and flower ring spot were found in a commercial crop in a greenhouse in Atibaia, São Paulo State. Electron microscopy, serology and biological assays indicated the presence of Tomato spotted wilt virus (TSWV. This is the first report of this pathogen in bellflower plants in Brazil.

  18. Disjunct population of redbay ambrosia beetle and laurel wilt disease discovered in Mississippi

    Science.gov (United States)

    J.J. Riggins; M. Hughes; J.A. Smith; R. Chapin

    2011-01-01

    Laurel wilt is an aggressive, non-native vascular wilt disease of redbay trees (Persea borbonia), sassafras (Sassafras albidum), and other plants within the Lauraceae family. The laurel wilt pathogen, (Raffaelea lauricola), is vectored by the redbay ambrosia beetle (Xyleborus glabratus), which...

  19. Bacterial Wilt in China: History, Current Status, and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Gaofei Jiang

    2017-09-01

    Full Text Available Bacterial wilt caused by plant pathogenic Ralstonia spp. is one of the most important diseases affecting the production of many important crops worldwide. In China, a large scientific community has been dedicated to studying bacterial wilt and its causative agent, Ralstonia pseudosolanacearum and R. solanacearum. Most of their work was published in Chinese, which has hindered international communication and collaboration in this field. In this review, we summarize the status of knowledge on geographical distribution, diversity, and host range of Ralstonia spp., as well as, the impact of bacterial wilt on important crops and disease control approaches, in China. We present areas of research and publications by Chinese scientists and propose the promotion of collaborative research within China and with the international community.

  20. The lecanindoles, nonsteroidal progestins from the terrestrial fungus Verticillium lecanii 6144.

    Science.gov (United States)

    Roll, Deborah M; Barbieri, Laurel R; Bigelis, Ramunas; McDonald, Leonard A; Arias, Daniel A; Chang, Li-Ping; Singh, Maya P; Luckman, Scott W; Berrodin, Thomas J; Yudt, Matthew R

    2009-11-01

    Four new indolosesquiterpenes, lecanindoles A-D (1-4), were isolated from fermentations of the terrestrial fungus Verticillium lecanii 6144. The structures of compounds 1-4 were elucidated from analysis of spectroscopic data. Compound 2 was reduced to give 4 and its isomer 5. Compound 4 was found to be a potent and selective progesterone receptor agonist with an EC50 of 1.1 +/- 0.4 nM in a cell-based luciferase reporter assay.

  1. Verticillium transcription activator of adhesion Vta2 suppresses microsclerotia formation and is required for systemic infection of plant roots.

    Science.gov (United States)

    Tran, Van-Tuan; Braus-Stromeyer, Susanna A; Kusch, Harald; Reusche, Michael; Kaever, Alexander; Kühn, Anika; Valerius, Oliver; Landesfeind, Manuel; Aßhauer, Kathrin; Tech, Maike; Hoff, Katharina; Pena-Centeno, Tonatiuh; Stanke, Mario; Lipka, Volker; Braus, Gerhard H

    2014-04-01

    Six transcription regulatory genes of the Verticillium plant pathogen, which reprogrammed nonadherent budding yeasts for adhesion, were isolated by a genetic screen to identify control elements for early plant infection. Verticillium transcription activator of adhesion Vta2 is highly conserved in filamentous fungi but not present in yeasts. The Magnaporthe grisea ortholog conidiation regulator Con7 controls the formation of appressoria which are absent in Verticillium species. Vta2 was analyzed by using genetics, cell biology, transcriptomics, secretome proteomics and plant pathogenicity assays. Nuclear Vta2 activates the expression of the adhesin-encoding yeast flocculin genes FLO1 and FLO11. Vta2 is required for fungal growth of Verticillium where it is a positive regulator of conidiation. Vta2 is mandatory for accurate timing and suppression of microsclerotia as resting structures. Vta2 controls expression of 270 transcripts, including 10 putative genes for adhesins and 57 for secreted proteins. Vta2 controls the level of 125 secreted proteins, including putative adhesins or effector molecules and a secreted catalase-peroxidase. Vta2 is a major regulator of fungal pathogenesis, and controls host-plant root infection and H2 O2 detoxification. Verticillium impaired in Vta2 is unable to colonize plants and induce disease symptoms. Vta2 represents an interesting target for controlling the growth and development of these vascular pathogens. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  2. Rosemary wilting disease and its management by soil solarization ...

    African Journals Online (AJOL)

    Three fungal pathogens including Phytophthora citrophthora, Rhizoctonia solani and Fusarium oxysporum were determined, whereas Helicotylenchus spp. was also associated. Pathogenicity tests proved that they were wilting pathogens, although P. citrophthora was the major pathogen in the field and glasshouses. This is ...

  3. Banana Xanthomonas wilt in Ethiopia: Occurrence and insect vector ...

    African Journals Online (AJOL)

    Bacterial wilt caused by Xanthomonas vasicola pv. musacearum (Xvm) is an important disease of enset and banana in south and south-western Ethiopia where, the diversity of the insect fauna on banana inflorescences was unknown and the role of insects as vectors of the disease had not been studied. The objectives of ...

  4. Potato bacterial wilt management in the Central Highlands of Ethiopia

    African Journals Online (AJOL)

    In Ethiopia, bacterial wilt caused by Ralstonia solanacearumis the major threat to potato production. Farmers are not aware of the causes of potato diseases and they believe that all types of diseases are caused by rain and mist. Research has been carried out in four districts namely Shashemene, Tulubolo, Welmera and ...

  5. Potato Bacterial Wilt Management in the Central Highlands of ...

    African Journals Online (AJOL)

    In Ethiopia, bacterial wilt caused by Ralstonia solanacearumis the major threat to potato production. Farmers are not aware of the causes of potato diseases and they believe that all types of diseases are caused by rain and mist. Research has been carried out in four districts namely Shashemene, Tulubolo, Welmera and ...

  6. Wilting, Molasses, and Inoculants for Alfalfa Ensilage: A

    African Journals Online (AJOL)

    changiz

    Keywords: Alfalfa silage, chemical composition, Ecosyl, Lalsil, additive, wilting, gas production. # Corresponding author: khorvash@cc.iut.ac.ir. Introduction. Optimal rumen health and profitable production of the modern ruminant industry dictate improving fibre digestion. Lucerne in the form of hay rather than silage, makes ...

  7. Preliminary evaluation of guava selections for guava wilt disease ...

    African Journals Online (AJOL)

    Guava wilt disease (GWD), caused by Nalanthamala psidii, is a serious disease occurring in the guava-producing areas of the Mpumalanga and Limpopo provinces of South Africa. Two resistant guava rootstocks, TS-G1 and 'TS-G2', were developed by the ARC-ITSC in 1995. In 2009, a renewed outbreak of GWD was ...

  8. Laurel wilt: A global threat to avocado production

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial avocado production in Florida, as well as the National Germplasm Repository for avocado in Miami (USDA-ARS). Elsewhere in the US, major (California) and minor comm...

  9. The role of NSm during tomato spotted wilt virus infection

    NARCIS (Netherlands)

    Storms, M.M.H.

    1998-01-01

    In the past ten years the genome organisation of tomato spotted wilt virus (TSWV) has been intensively studied in our laboratory. Complete genome sequence data revealed that this enveloped plant virus belongs to the Bunyaviridae, a virus family further restricted to

  10. Integrated management of Fusarium wilt of chickpea ( Cicer ...

    African Journals Online (AJOL)

    The present study was carried out to assess the efficacy of an integrated management strategy for Fusarium wilt of chickpea that combined the use of microbial antagonist, botanical extract and fungicide. Before setting the experiment in field micro plots, a series of in vitro and in vivo experiments were conducted to select a ...

  11. Banana Xanthomonas wilt: a review of the disease, management ...

    African Journals Online (AJOL)

    The economic impact of banana Xanthomonas wilt is not fully understood but its impact on food security in the region is very significant. While germplasm screening for the disease is ongoing, efforts to genetically engineer resistance in some banana cultivars are also making good progress. This paper presents a review of ...

  12. Fungi Associated With Tomato Wilt In The Tropical Humid Lowlands ...

    African Journals Online (AJOL)

    Isolations on potato dextrose agar (PDA) showed that the following fungi were frequently associated with naturally infected, wilted tomato plants in Umudike: Fusarium oxysporum, f.sp. lycopersici, F.solani, F.equiseti, F.acuminatum, Trichoderma viride, T.harzianum, Mucor hiemalis, Sclerotium rolfsii, Phoma lycopersici and ...

  13. Transgenic tomato hybrids resistant to tomato spotted wilt virus infection.

    NARCIS (Netherlands)

    Haan, de P.; Ultzen, T.; Prins, M.; Gielen, J.; Goldbach, R.; Grinsven, van M.

    1996-01-01

    Tomato spotted wilt virus (TSWV) infections cause significant economic losses in the commercial culture of tomato (Lycopersicon esculentum). Culture practices have only been marginally effective in controlling TSWV. The ultimate way to minimize losses caused by TSWV is resistant varieties. These can

  14. The changing spread dynamics of banana Xanthomonas wilt (BXW ...

    African Journals Online (AJOL)

    Banana Xanthomonas wilt still remains a serious threat to banana production in Uganda. Although the desired long term control strategy would have been use of resistance, no sources of resistance have been found. Further the transgenic resistance under development will only be deployed in the long run. In the meantime ...

  15. Mechanical transmission and survival of bacterial wilt on enset ...

    African Journals Online (AJOL)

    The transmission of enset bacterial wilt with contaminated knives and the survival of the causal agent in soil and enset plant debris was studied at the Awassa Agricultural Research Center, Awassa, Ethiopia. Contaminated knives were found to transmit the pathogen from infected to healthy plants. Disease symptoms were ...

  16. Laurel wilt in avocado: Review of an emerging disease

    Science.gov (United States)

    aurel wilt, caused by the vascular fungus Raffaelea lauricola, is transmitted by the redbay ambrosia beetle, Xyleborus glabratus, and affects many plants in the family Lauraceae. It was introduced into the United States around 2002 through infested packing material arriving in Georgia. In Florida, t...

  17. The origin of Ceratocystis fagacearum, the oak wilt fungus

    Science.gov (United States)

    Jennifer Juzwik; Thomas C. Harrington; William L. MacDonald; David N. Appel

    2008-01-01

    The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes...

  18. Integrated management of Fusarium wilt of chickpea (Cicer ...

    African Journals Online (AJOL)

    user

    2013-07-17

    Jul 17, 2013 ... reduces Fusarium wilt in the field (Chand and Singh,. 2005). However, biological suppression of plant disease is often subjected to ecological limitations and is not suffi- cient alone to escape the pathogen under field con- ditions. Instead, biological control when used in combina-tion with other management ...

  19. Reaction of Musa balbisiana to Banana bacterial wilt infection ...

    African Journals Online (AJOL)

    The expression of NPR1, a marker gene of the systemic acquired resistance plant defence system provides preliminary evidence that this may be the major form of resistance in Musa balbisiana to bacterial wilt infection. Keywords: NPR1, PR proteins, Uganda, Xanthomonas campestris. African Crop Science Journal, Vol.

  20. Wilting, Molasses, and Inoculants for Alfalfa Ensilage: A

    African Journals Online (AJOL)

    changiz

    feeding degradation rate. (Sniffen et al. .... microbial heat shock, the bottles were warmed up to 39 °C for 30 min before and while adding the mixture of ... Data were analyzed by using the Mixed Procedure of SAS (2003) with fixed effects of wilting,.

  1. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease

    NARCIS (Netherlands)

    Lowe-Power, Tiffany M.; Hendrich, Connor G.; Roepenack-Lahaye, von Edda; Li, Bin; Wu, Dousheng; Mitra, Raka; Dalsing, Beth L.; Ricca, Patrizia; Naidoo, Jacinth; Cook, David; Jancewicz, Amy; Masson, Patrick; Thomma, Bart; Lahaye, Thomas; Michael, Anthony J.; Allen, Caitilyn

    2017-01-01

    Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from

  2. Paecilomyces lilacinus and Verticillium chlamydosporium Fungi as Biological Control of Fasciolosis

    Directory of Open Access Journals (Sweden)

    Riza Zainuddin Ahmad

    2013-09-01

    Full Text Available Fasciolosis is a worm disease caused of Fasciola gigantica and an important problem in husbandry especially for cattle. Controlling of this worm disease can be conducted by prevention and treatment. The use of antihelminthic is commonly causes a resistance problem. Natural control by mold such as Paecilomyces lilacinus and Verticillium chlamydosporium can be applied to reduce egg of F. gigantica. Although it was recently found, in vitro study gave satisfied result. This gives a new hope in controlling the disease although the extend application still needs to be studied. This paper discussed about the use of P. lilacinus and V. chlamydosporium for reducing F. gigantica population.

  3. Genetic and environmental control of the Verticillium syndrome in Arabidopsis thaliana.

    Science.gov (United States)

    Häffner, Eva; Karlovsky, Petr; Diederichsen, Elke

    2010-11-02

    Verticillium spp. are major pathogens of dicotyledonous plants such as cotton, tomato, olive or oilseed rape. Verticillium symptoms are often ambiguous and influenced by development and environment. The aim of the present study was to define disease and resistance traits of the complex Verticillium longisporum syndrome in Arabidopsis thaliana (L.) Heynh. A genetic approach was used to determine genetic, developmental and environmental factors controlling specific disease and resistance traits and to study their interrelations. A segregating F2/F3 population originating from ecotypes 'Burren' (Bur) and 'Landsberg erecta' (Ler) was established. Plants were root-dip inoculated and tested under greenhouse conditions. The Verticillium syndrome was dissected into components like systemic spread, stunting, development time and axillary branching. Systemic spread of V. longisporum via colonisation of the shoot was extensive in Ler; Bur showed a high degree of resistance against systemic spread. Fungal colonisation of the shoot apex was determined by (a) determining the percentage of plants from which the fungus could be re-isolated and (b) measuring fungal DNA content with quantitative real-time PCR (qPCR). Four quantitative trait loci (QTL) controlling systemic spread were identified for the percentage of plants showing fungal outgrowth, two of these QTL were confirmed with qPCR data. The degree of colonisation by V. longisporum was negatively correlated with development time. QTL controlling development time showed some overlap with QTL for resistance to systemic spread. Stunting depended on host genotype, development time and seasonal effects. Five QTL controlling this trait were identified which did not co-localize with QTL controlling systemic spread. V. longisporum induced increased axillary branching in Bur; two QTL controlling this reaction were found. Systemic spread of V. longisporum in the host as well as resistance to this major disease trait are described for

  4. Genetic and environmental control of the Verticillium syndrome in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Diederichsen Elke

    2010-11-01

    Full Text Available Abstract Background Verticillium spp. are major pathogens of dicotyledonous plants such as cotton, tomato, olive or oilseed rape. Verticillium symptoms are often ambiguous and influenced by development and environment. The aim of the present study was to define disease and resistance traits of the complex Verticillium longisporum syndrome in Arabidopsis thaliana (L. Heynh. A genetic approach was used to determine genetic, developmental and environmental factors controlling specific disease and resistance traits and to study their interrelations. Results A segregating F2/F3 population originating from ecotypes 'Burren' (Bur and 'Landsberg erecta' (Ler was established. Plants were root-dip inoculated and tested under greenhouse conditions. The Verticillium syndrome was dissected into components like systemic spread, stunting, development time and axillary branching. Systemic spread of V. longisporum via colonisation of the shoot was extensive in Ler; Bur showed a high degree of resistance against systemic spread. Fungal colonisation of the shoot apex was determined by (a determining the percentage of plants from which the fungus could be re-isolated and (b measuring fungal DNA content with quantitative real-time PCR (qPCR. Four quantitative trait loci (QTL controlling systemic spread were identified for the percentage of plants showing fungal outgrowth, two of these QTL were confirmed with qPCR data. The degree of colonisation by V. longisporum was negatively correlated with development time. QTL controlling development time showed some overlap with QTL for resistance to systemic spread. Stunting depended on host genotype, development time and seasonal effects. Five QTL controlling this trait were identified which did not co-localize with QTL controlling systemic spread. V. longisporum induced increased axillary branching in Bur; two QTL controlling this reaction were found. Conclusions Systemic spread of V. longisporum in the host as well as

  5. Stem Nematode-Fusarium Wilt Complex in Alfalfa as Related to Irrigation Management at Harvest Time

    OpenAIRE

    Griffin, G. D.

    1992-01-01

    A high moisture level in the top 10 cm of soil at time of cutting of alfalfa increased the incidence of plant mortality and Fusarium wilt in soil infested with Ditylenchus dipsaci and Fusarium oxysporum f. sp. medicaginis in greenhouse and field microplot studies. Ranger alfalfa, susceptible to both D. dipsaci and F. oxysporum f. sp. medicaginis, was less persistent than Moapa 69 (nematode susceptible and Fusarium wilt resistant) and Lahontan alfalfa (nematode resistant with low Fusarium wilt...

  6. Microscopic observations on the interaction of the mycoparasite Verticillium biguttatum with Rhizoctonia solani and other soil-borne fungi

    NARCIS (Netherlands)

    Boogert, P.H.J.F. van den; Reinartz, H.; Sjollema, K.A.; Veenhuis, M.

    The mycoparasitic interactions of Verticillium biguttatum with Rhizoctonia solani and with a variety of other soil-borne fungi were investigated in dual cultures. V. biguttatum interacted with various soil fungi by appressed growth along the host hyphae and infrequent penetrations. Intracellular

  7. Media for efficient generating nitrate- - nonutilizing (NIT) mutants of Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum.

    NARCIS (Netherlands)

    Rataj-Guranowska, M.; Pieczul, K.; Nowak, E.; Hiemstra, J.A.; Drapikowska, M.

    2001-01-01

    The effect of several media amended wit potassium chlorate (1.5% and 6%) on generation of nit mutants, especially nit M mutants from Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum were studied. For all species minimal medium with 6%

  8. Improvement of the efficacy of Verticillium lecanii used in biocontrol of Sphaerotheca fuliginea by addition of oil formulations

    NARCIS (Netherlands)

    Verhaar, M.A.; Hijwegen, T.; Zadoks, J.C.

    1999-01-01

    Biocontrol of cucumber powdery mildew, Sphaerotheca fuliginea, by Verticillium lecanii is seriously hampered at low humidities. The effect is especially marked at low humidity (60% RH) during the three hours following the application of V. lecanii spores suspended in water. Formulations of V.

  9. Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts

    OpenAIRE

    ZHANG Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

    2016-01-01

    Background Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China. TSWV and TZSV belong to different serogroup of tospoviruses but induce similar symptoms in the same host plant species, which makes diagnostic difficult. We used different electron microscopy preparing methods to investigate clustering and cellular distribution of...

  10. Transgenic tomato hybrids resistant to tomato spotted wilt virus infection.

    OpenAIRE

    de Haan,; Ultzen, T.; Prins, M; Gielen, J.; Goldbach, R; Grinsven, van, Saskia

    1996-01-01

    Tomato spotted wilt virus (TSWV) infections cause significant economic losses in the commercial culture of tomato (Lycopersicon esculentum). Culture practices have only been marginally effective in controlling TSWV. The ultimate way to minimize losses caused by TSWV is resistant varieties. These can be obtained by introgression of natural sources of resistance from wild relatives or by expressing viral sequences in transgenic tomato plants. We report high levels of resistance to TSWV obtained...

  11. How to identify and manage oak wilt in Texas

    Science.gov (United States)

    D. N. Appel; R. S. Cameron; A. D. Wilson; J. D. Johnson.

    2008-01-01

    Measures can be taken to break root connections between live oaks or dense groups of red oaks to reduce or stop root transmission of the oak wilt fungus. The most common technique is to sever roots by trenching at least 4 ft deep with trenching machines, rock saws, or ripper bars. Trenches more than 4 ft deep may be needed to assure control in deeper soils. Although...

  12. Bacterial community associated with ensilage process of wilted guinea grass.

    Science.gov (United States)

    Parvin, S; Nishino, N

    2009-12-01

    To determine the effects of wilting, storage period and bacterial inoculant on the bacterial community and ensiling fermentation of guinea grass silage. Fermentation products, colony counts and denaturing gradient gel electrophoresis (DGGE) profiles were determined. There was more lactic acid than acetic acid in all silages, but the lactic acid to acetic acid ratio decreased with storage time. This shift from lactic to acetic acid was not prevented even with a combination of wilting and bacterial inoculant. The DGGE analyses suggest that facultatively heterofermentative lactic acid bacteria (Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus pentosus) were involved in the shift to acetic acid fermentation. Lactic acid can dominate the fermentation in tropical grass silage with sufficient wilting prior to ensiling. Prolonged storage may lead to high levels of acetic acid without distinctive changes in the bacterial community. The bacterial community looks stable compared to fermentation products over the course of long storage periods in tropical grass silage. Acetic acid fermentation in tropical grass silage can be a result of the changes in bacterial metabolism rather than community structure.

  13. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    Directory of Open Access Journals (Sweden)

    DWI SURYANTO

    2010-03-01

    Full Text Available Biological control of plant disease using antagonistic microorganism has been obtaining much attention and implemented for decades. One of the potential microorganisms used in this strategy is chitinolytic bacteria. Utilization of this bacteria ranges from cell life, enzymes, genes, or other metabolites. In this study, we examined the ability of chitinolytic bacteria as a biocontrol agent of Fusarium wilt of red chili (Capsicum annuum L. seedlings. The ability of chitinolytic bacteria to suppress the disease was evaluated by soaking red chili seeds in the bacterial isolates solution for 30 minutes prior seedling. Percentage of seedling of treated chili seed at end of study (4-weeks ranging from 46 to 82.14%. Relative reduction of the seedling damping-off was observed in all bacterial treatment ranged from 28.57 to 60.71%. Furthermore, manifestation of bacterial suppression to Fusarium wilt was also exhibited by increasing of seedling height (ranged from 7.33 to 7.87 cm compared to 6.88 cm and dry-weight (ranged from 2.7 to 4.3 mg compared to 2.3 mg. However, no significant effect was observed in leaf number. Then, from all chitinolytic isolates tested, BK08 was the most potential candidate for biological control agent of Fusarium wilt in chili seedling.

  14. [Inhibitory effects of natural plant extracts on Verticillium albo-atrum].

    Science.gov (United States)

    Zhang, Shuhong; Zhou, Baoli; Zhang, Lei; Fu, Yawen

    2006-06-01

    This paper studied the inhibitory effects of 54 kinds of ethanol-extracted plant solutions on Verticillium albo-atrum. The results showed that 15 kinds of these extracts could inhibit the growth of verticillium albo-atrum mycelium, with an inhibitory rate more than 50%, among which, the inhibitory rate of Asarum sieboldii, Coptis chinensis, Magnolia officinalis, Acacia catechu, Sophora flavescens, Glycyrrhiza uralensis, Cnidium monnieri, Platycodon grandiflorum and Allium. cepa. extracts was higher than 65%, and that of Cnidium monnieri extract reached 86.84%. A total of 16 kinds of plant extracts decreased the spore germination of V. albo-atrum, with the inhibitory rate higher than 70%, and there were 7 kinds of plant extracts whose inhibitory rate reached 95%. Almost no spore bourgeon was found after treated with Asarum sieboldii, Coptis chinensis, and Magnolia officinalis extracts. The extract of Acacia catechu did not inhibit the growth of mycelium, but restrained the spore germination by 100%. Cnidium monnieri extract could strongly inhibit the growth of mycelium, but had a less effect on spore germination rate (only by 11.3%). The active substances found in natural plant extracts which had the inhibitory effects on pathogen brought us a new and promising method to deal with V. albo-atrum and other vegetable diseases.

  15. Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

    Directory of Open Access Journals (Sweden)

    Anastasis Antoniou

    2017-11-01

    Full Text Available Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects. While suppressiveness is usually attributed to the compost’s microorganisms, the mechanisms governing microbial recruitment by the roots and the composition of selected microbial communities are not fully elucidated. Herein, the purpose of the study was to evaluate the impact of a compost on tomato plant growth and its suppressiveness against Fusarium oxysporum f. sp. lycopersici (Foxl and Verticillium dahliae (Vd. First, growth parameters of tomato plants grown in sterile peat-based substrates including 20 and 30% sterile compost (80P/20C-ST and 70P/30C-ST or non-sterile compost (80P/20C and 70P/30C were evaluated in a growth room experiment. Plant height, total leaf surface, and fresh and dry weight of plants grown in the non-sterile compost mixes were increased compared to the plants grown in the sterile compost substrates, indicating the plant growth promoting activity of the compost’s microorganisms. Subsequently, compost’s suppressiveness against Foxl and Vd was evaluated with pathogenicity experiments on tomato plants grown in 70P/30C-ST and 70P/30C substrates. Disease intensity was significantly less in plants grown in the non-sterile compost than in those grown in the sterile compost substrate; AUDPC was 2.3- and 1.4-fold less for Foxl and Vd, respectively. Moreover, fungal quantification in planta demonstrated reduced colonization in plants grown in the non-sterile mixture. To further investigate these findings, we characterized the culturable microbiome attracted by the roots compared to the unplanted compost. Bacteria and fungi isolated from unplanted compost and the rhizosphere of plants were sequence-identified. Community

  16. Mating Test and In Vitro Production of Perithecia by the Coffee Wilt ...

    African Journals Online (AJOL)

    Gibberella xylarioides Heim & Saccas, the teleomorphic state of Fusarium xylarioides Steyaert, is a fungal pathogen causing a vascular wilt disease of coffee known as tracheomycosis. Coffee wilt disease has been one of the endemic diseases of Arabica coffee (Coffea arabica) with increasing outbreaks and prevalence in ...

  17. Using classification tree analysis to predict oak wilt distribution in Minnesota and Texas

    Science.gov (United States)

    Marla c. Downing; Vernon L. Thomas; Jennifer Juzwik; David N. Appel; Robin M. Reich; Kim Camilli

    2008-01-01

    We developed a methodology and compared results for predicting the potential distribution of Ceratocystis fagacearum (causal agent of oak wilt), in both Anoka County, MN, and Fort Hood, TX. The Potential Distribution of Oak Wilt (PDOW) utilizes a binary classification tree statistical technique that incorporates: geographical information systems (GIS...

  18. Recovery plan for laurel wilt of avocado, caused by Raffaelea lauricola

    Science.gov (United States)

    R. C . Ploetz; S. W . Fraedrich; L. L. Stelinski; J. Hulcr; A. E. Mayfield III; T. L. Dreaden; J. H . Crane; E. A. Evans; B. A. Schaffer; J. A. Rollins

    2017-01-01

    Summary. Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial production in the United States and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the National Germplasm Repository for avocado in Miami (USDA-ARS) and...

  19. Recovery plan for laurel wilt of avocado, caused by Raffaelea lauricola

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana), an important commercial fruit crop. The disease threatens commercial production in the US and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the N...

  20. Current •·esearcb trends on coffee wilt disease tracheomycosis

    African Journals Online (AJOL)

    increase soil acidity (Kebe, 1997) favoured Fusarium wilt of oil palms. Clearly there is a role played by natural and cultural environment in the epidemiology of the disease. Cultivation of robusta coffee cultivars with resistance to wilt is the only effective method to reduce losses due to tracheomycosis. Use of resistant cultivars ...

  1. Sulfuryl fluoride fumigation of red oak logs eradicates the oak wilt fungus

    Science.gov (United States)

    Elmer L. Schmidt; Jennifer Juzwik; Brian Schneider

    1997-01-01

    Preliminary field trials using red oak logs from trees dying from oak wilt disease were successful in eliminating oak wilt fungus from sapwood after fumigation with sulfuryl fluoride for 72 h under tarp. These results support earlier laboratory data on the fungitoxicity of sulfuryl fluoride as a potential replacement for methyl bromide of exported red oak veneer logs....

  2. A review of oak wilt management: a summary of treatment options and their efficacy

    Science.gov (United States)

    Karrie A. Koch; Gina L. Quiram; Robert C. Venette

    2010-01-01

    Oak wilt, caused by the invasive fungal pathogen Ceratocystis fagacearum (Bretz) Hunt, is a serious and fatal disease of oaks, Quercus spp., with red oaks (section Lobatae) generally being more susceptible than white oaks (section Quercus). Oak wilt was first recognized in North America in 1944...

  3. Molecular and metabolic changes of cherelle wilt of cacao and its effect on Moniliophthora roreri

    Science.gov (United States)

    The seeds of Theobroma cacao L. pods are processed into cocoa products. Cherelle wilt is physiological thinning of young pods that result in loss of potential pods. Cherelle wilt first occurs 50 days after pollination (DAP) and a second thinning occurs around 70 DAP. Cherelles are also highly sus...

  4. Plant-derived Antibacterial Metabolites Suppressing Tomato Bacterial Wilt Caused by Ralstonia solanacearum

    Directory of Open Access Journals (Sweden)

    Thuy Thu Vu

    2017-06-01

    Full Text Available Ralstonia solanacearum species complex (RSSC causes bacterial wilt, and it is one of the most important soil-borne plant pathogenic bacteria. RSSC has a large host range of more than 50 botanical families, which represent more than 200 plant species, including tomato. It is difficult to control bacterial wilt due to following reasons: the bacterial wilt pathogen can grow inside the plant tissue, and it can also survive in soil for a long period; moreover, it has a wide host range and biological diversity. In most previous studies, scientists have focused on developing biological control agents, such as antagonistic microorganisms and botanical materials. However, biocontrol attempts are not successful. Plant-derived metabolites and extracts have been promising candidates to environmentally friendly control bacterial wilt diseases. Therefore, we review the plant extracts, essential oils, and secondary metabolites that show potent in vivo antibacterial activities (in potted plants or in field against tomato bacterial wilt, which is caused by RSSC.

  5. Potential for using Verticillium albo-atrum as a biocontrol agent for tree-of-heaven (Ailanthus altissima)

    Science.gov (United States)

    Donald D. Davis; Matthew Kasson; Mark. Schall

    2011-01-01

    Extensive, unprecedented wilt and mortality of the highly invasive, exotic tree-of-heaven (Ailanthus altissima) occurred recently within mixed hardwood forests in south-central Pennsylvania. Until this study, the cause of the epidemic was unknown.

  6. Effect of Verticillium dahliae soil inoculum levels on spinach seed infection

    DEFF Research Database (Denmark)

    Sapkota, Rumakanta; Olesen, Merete Halkjær; Deleuran, Lise Christina

    2016-01-01

    Verticillium dahliae is a soilborne pathogen and a threat to spinach seed production. The aim of this study was to understand the relation between V. dahliae soil inoculum and infection in harvested seed. Quantitative polymerase chain reaction was used for quantification of the pathogen. Semifield...... experiments in which spinach was grown in soils with different inoculum levels enabled us to determine a threshold level for V. dahliae DNA of 0.003 ng/g of soil for seed infection to occur. Soils from production fields were sampled in 2013 and 2014 during and before planting, as well as the harvested seed....... Seed from plants grown in infested soils were infected with V. dahliae in samples from both the semifield and open-field experiments. Lower levels of pathogen were found in seed from spinach grown in soils with a scattered distribution of V. dahliae (one or two positive of three soil subsamples) than...

  7. Verticillium Ave1 effector induces tomato defense gene expression independent of Ve1 protein.

    Science.gov (United States)

    Castroverde, Christian Danve M; Nazar, Ross N; Robb, Jane

    2016-11-01

    Verticillium resistance is thought to be mediated by Ve1 protein, which presumably follows a "gene-for-gene" relationship with the V. dahliae Ave1 effector. Because in planta analyses of Ave1 have relied so far on transient expression of the gene in tobacco, this study investigated gene function using stably expressing 35S:Ave1 transgenic tomato. Transgenic Ave1 expression was shown to induce various defense genes including those coding for PR-1 (P6), PR-2 (βbeta-1,3-glucanase) and peroxidases (anionic peroxidase 2, Cevi16 peroxidase). Since a Ve1(-) tomato cultivar served as germplasm, these results indicate that Ave1 induces these defense genes independently of Ve1.

  8. The effects of wilting and storage temperatures on the fermentation quality and aerobic stability of stylo silage.

    Science.gov (United States)

    Liu, Qinghua; Zhang, Jianguo; Shi, Shangli; Sun, Qizhong

    2011-08-01

    In order to clarify the ensiling characteristics of stylo (Stylosanthes guianensis Swartz), the effects of wilting (no wilting, light wilting and heavy wilting) and storage temperatures (10°C, 20°C, 30°C and 40°C) on the fermentation quality and aerobic stability of stylo silage were investigated. Wilting had no significant influence on the contents of crude protein, ether extract and acid detergent fiber, and numbers of lactic acid bacteria, aerobic bacteria, yeasts and mold (P > 0.05). Heavy wilted material, wilted for 12 h, had higher neutral detergent fiber content and lower water-soluble carbohydrate content than unwilted and light wilted materials (P silage (P fermentation quality of stylo silage. In all the silages, no wilting silage ensiled at 30°C had the highest butyric acid content (P silage, irrespective of wilting. The wilted silage or silage stored at low temperature had poor aerobic stability. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

  9. Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1

    OpenAIRE

    Gaspar, Yolanda M.; McKenna, James A.; McGinness, Bruce S.; Hinch, Jillian; Poon, Simon; Connelly, Angela A.; Anderson, Marilyn A.; Heath, Robyn L.

    2014-01-01

    The plant defensin NaD1, from Nicotiana alata, has potent antifungal activity against a range of filamentous fungi including the two important cotton pathogens, Fusarium oxysporum f. sp. vasinfectum (Fov) and Verticillium dahliae. Transgenic cotton plants expressing NaD1 were produced and plants from three events were selected for further characterization. Homozygous plants were assessed in greenhouse bioassays for resistance to Fov. One line (D1) was selected for field trial testing over thr...

  10. Differential protein accumulations in isolates of the strawberry wilt pathogen Fusarium oxysporum f. sp. fragariae differing in virulence.

    Science.gov (United States)

    Fang, Xiangling; Barbetti, Martin J

    2014-08-28

    This study was conducted to define differences in Fusarium oxysporum f. sp. fragariae (Fof) isolates with different virulence efficiency to strawberry at the proteome level, in combination with their differences in mycelial growth, conidial production and germination. Comparative proteome analyses revealed substantial differences in mycelial proteomes between Fof isolates, where the 54 differentially accumulated protein spots were consistently over-accumulated or exclusively in the highly virulent isolate. These protein spots were identified through MALDI-TOF/TOF mass spectrometry analyses, and the identified proteins were mainly related to primary and protein metabolism, antioxidation, electron transport, cell cycle and transcription based on their putative functions. Proteins of great potential as Fof virulence factors were those involved in ubiquitin/proteasome-mediated protein degradation and reactive oxygen species detoxification; the hydrolysis-related protein haloacid dehalogenase superfamily hydrolase; 3,4-dihydroxy-2-butanone 4-phosphate synthase associated with riboflavin biosynthesis; and those exclusive to the highly virulent isolate. In addition, post-translational modifications may also make an important contribution to Fof virulence. F. oxysporum f. sp. fragariae (Fof), the causal agent of Fusarium wilt in strawberry, is a serious threat to commercial strawberry production worldwide. However, factors and mechanisms contributing to Fof virulence remained unknown. This study provides knowledge of the molecular basis for the differential expression of virulence in Fof, allowing new possibilities towards developing alternative and more effective strategies to manage Fusarium wilt. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Reduction of Fusarium wilt in watermelon by Pseudomonas chlororaphis PCL1391 and P. fluorescens WCS365

    Directory of Open Access Journals (Sweden)

    G.T. Tziros

    2007-12-01

    Full Text Available Fusarium wilt of watermelon (Citrullus lanatus caused by Fusarium oxysporum f. sp. niveum is a devastatine soil-borne disease that causes extensive losses throughout the world. Two known Pseudomonas biocontrol strains were used separately and in combination to assess their antagonistic effectiveness against F. oxysporum f. sp. niveum in pot experiments. P. chlororaphis PCL1391 signifi cantly reduced disease severity. P. fl uorescens WCS365 was less effective in disease suppression, while a combination of the two bacteria had intermediate effects. The biological control of Fusarium wilt with P. chlororaphis offers a potentially useful tool in an integrated pest management program to control Fusarium wilt of watermelon.

  12. Allelopathy of root exudates from different resistant eggplants to ...

    African Journals Online (AJOL)

    Three eggplant cultivars were inoculated with Verticillium dahliae Kleb. to assess their resistance to Verticillium wilt. Solanum tor was resistant, “Liyuanziqie” was tolerant, and “Xi'anlvqie” susceptible. The disease incidence and disease index of Verticillium wilt and the amount of V. dahliae in rhizospheric soil, variation of ...

  13. Molecular research and genetic engineering of resistance to ...

    African Journals Online (AJOL)

    Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing crop's production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became effectively controlled in recent ...

  14. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    Directory of Open Access Journals (Sweden)

    Amyotte Stefan G

    2012-07-01

    Full Text Available Abstract Background Verticillium dahliae (Vd and Verticillium albo-atrum (Va are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating genetic diversity. Whole genome comparative analysis of the recently sequenced strains VdLs.17 and VaMs.102 revealed that non-random insertions of transposable elements (TEs have contributed to the generation of four lineage-specific (LS regions in VdLs.17. Results We present here a detailed analysis of Class I retrotransposons and Class II “cut-and-paste” DNA elements detected in the sequenced Verticillium genomes. We report also of their distribution in other Vd and Va isolates from various geographic origins. In VdLs.17, we identified and characterized 56 complete retrotransposons of the Gypsy-, Copia- and LINE-like types, as well as 34 full-length elements of the “cut-and-paste” superfamilies Tc1/mariner, Activator and Mutator. While Copia and Tc1/mariner were present in multiple identical copies, Activator and Mutator sequences were highly divergent. Most elements comprised complete ORFs, had matching ESTs and showed active transcription in response to stress treatment. Noticeably, we found evidences of repeat-induced point mutation (RIP only in some of the Gypsy retroelements. While Copia-, Gypsy- and Tc1/mariner-like transposons were prominent, a large variation in presence of the other types of mobile elements was detected in the other Verticillium spp. strains surveyed. In particular, neither complete nor defective “cut-and-paste” TEs were found in VaMs.102. Conclusions Copia-, Gypsy- and Tc1/mariner-like transposons are the most wide-spread TEs in the phytopathogens V. dahliae and V. albo-atrum. In VdLs.17, we identified several retroelements and “cut-and-paste” transposons still potentially active. Some of these

  15. Effectiveness of composts and Trichoderma strains for control of Fusarium wilt of tomato

    Directory of Open Access Journals (Sweden)

    Yousra TAGHDI

    2015-09-01

    Full Text Available Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL is a major limiting disease in tomato production in Morocco. Commercial and locally produced Moroccan composts and peat were found to reduce Fusarium wilt in tomato plants. We explored the presence of Trichoderma strains in these materials, and in six soils sampled in the North West of Morocco, where a low incidence of Fusarium wilt had been previously observed. The most abundant Trichoderma-like fungus was selected from each soil, compost or peat sample. Twelve Trichoderma strains were isolated and identified molecularly. Trichoderma asperellum CT9 and Trichoderma virens ST11 showed the greatest overall antagonistic activity against FOL, Rhizoctonia solani, Botrytis cinerea and Pythium ultimum. The three strains evaluated in in planta tests, CT9, ST11 and T. virens ST10, reduced tomato Fusarium wilt, and strain ST11  also promoted growth of tomato plants.

  16. The Arabidopsis transcription factor WRKY27 influences wilt disease symptom development caused by Ralstonia solanacearum

    National Research Council Canada - National Science Library

    Mukhtar, M. Shahid; Deslandes, Laurent; Auriac, Marie‐Christine; Marco, Yves; Somssich, Imre E

    2008-01-01

    .... Here we show that the Arabidopsis mutant wrky27‐1 , which lacks a functional WRKY27 transcription factor, showed delayed symptom development in response to the bacterial wilt pathogen Ralstonia solanacearum...

  17. Tomato spotted wilt virus infection improves host suitability for its vector Frankliniella occidentalis

    NARCIS (Netherlands)

    Maris, P.C.; Joosten, N.N.; Goldbach, R.W.; Peters, D.

    2004-01-01

    The effect of Tomato spotted wilt virus (TSWV) infection on plant attractiveness for the western flower thrips (Frankliniella occidentalis) was studied. Significantly more thrips were recovered on infected than were recovered on noninfected pepper (Capsicum annuum) plants in different preference

  18. The origin of Ceratocystis fagacearum, the oak wilt fungus.

    Science.gov (United States)

    Juzwik, Jennifer; Harrington, Thomas C; MacDonald, William L; Appel, David N

    2008-01-01

    The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes in land use, and forest management created conditions favorable for disease epidemics. The host genus Quercus contains some relatively resistant species native to the United States, further supporting the hypothesis that the pathogen is native in origin. However, there are also many common, highly susceptible Quercus species--a characteristic typical of introduced pathogens. Most convincingly, studies have shown that the known populations of C. fagacearum have experienced a severe genetic bottleneck that can only be explained by a single introduction. The weight of evidence indicates that C. fagacearum is an introduced pathogen, with possible origins in Central or South America, or Mexico.

  19. The xylem as battleground for plant hosts and vascular wilt pathogens

    OpenAIRE

    Koste eYadeta; Bart eThomma

    2013-01-01

    Vascular wilts are among the most destructive plant diseases that occur in annual crops as well as in woody perennials. These diseases are generally caused by soil-borne bacteria, fungi, and oomycetes that infect through the roots and enter the water-conducting xylem vessels where they proliferate and obstruct the transportation of water and minerals. As a consequence, leaves wilt and die, which may lead to impairment of the whole plant and eventually to death of the plant. Cultural, chemical...

  20. Epidemiology of spotted wilt disease of peanut caused by Tomato spotted wilt virus in the southeastern U.S.

    Science.gov (United States)

    Culbreath, A K; Srinivasan, R

    2011-08-01

    Spotted wilt disease of peanut (Arachis hypogaea) (SWP), caused by Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae), was first observed in Alabama, Florida, and Georgia in the late 1980s and rapidly became a major limiting factor for peanut production in the region. Tobacco thrips (Frankliniella fusca) and western flower thrips (Frankliniella occidentalis) both occur on peanut throughout the southeastern U.S., but F. fusca is the predominant species that reproduces on peanut, and is considered to be the more important vector. Several non-crop sources of potential primary vectors and TSWV inoculum have been identified, but their relative importance has not been determined. The peanut growing season in Alabama, Florida, and Georgia is from April through November, and 'volunteer' peanut plants can be present for much of the remainder of the year. Therefore peanut itself has huge potential for perpetuating both vector and virus. Symptoms are often evident within a few days of seedling emergence, and disease progress is often rapid within the first 50-60 days after planting. Based on destructive sampling and assays for TSWV, there is often a high incidence of asymptomatic infections even in peanut genotypes that produce few and mild symptoms of infection in the field. Severity of SWP epidemics fluctuates significantly from year to year. The variability has not been fully explained, but lower incidences have been associated with years categorized as "La Niña" in the El Niño-Southern Oscillation. Planting date can have a large effect on disease incidence within a location. This may be linked to the thrips reproductive cycle and environmental effects on the plant and plant-thrips-virus interactions. Row pattern, plant population, and in-furrow applications of phorate insecticide can also affect epidemics of SWP. Considerable progress has been made in developing cultivars with natural field resistance to TSWV. Use of cultivars with moderate field

  1. Properties of a hydrophobin isolated from the mycoparasitic fungus Verticillium fungicola.

    Science.gov (United States)

    Calonje, Myriam; Bernardo, Dolores; Novaes-Ledieu, Monique; García Mendoza, Concepción

    2002-11-01

    Verticillium fungicola, isolated from Agaricus bisporus (commercial mushroom), produced significant extracellular hydrophobin when grown for 7 days in a static liquid culture of synthetic minimal medium. The hydrophobin was purified by precipitation with ammonium sulphate (80% saturation), Sephadex G-100 gel filtration, and hydroxyapatite column chromatography. The purified protein yielded a single band in polyacrylamide gel electrophoresis under native conditions, with an apparent molecular mass of 70 +/- 4 kDa, and also another single band in SDS-PAGE, with a molecular mass of 7 +/- 3 kDa. Molecular mass determined with matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) resulted in 7563.9 m/z. The same protein was extracted from the V. fungicola mycelium. Analysis of the amino acid composition revealed the presence of about 50% hydrophobic residues, detecting at least six cysteines, evaluated as cystines, and no free sulfhydryl groups. The protein did not show any glycosylation. On the basis of similarities in hydropathy patterns and solubility characteristics, V. fungicola hydrophobin can be included as a new member of Class II hydrophobins.

  2. Biological Control of Sclerotium rolfsii and Verticillium dahliae by Talaromyces flavus Is Mediated by Different Mechanisms.

    Science.gov (United States)

    Madi, L; Katan, T; Katan, J; Henis, Y

    1997-10-01

    ABSTRACT Ten wild-type strains and two benomyl-resistant mutants of Talaromyces flavus were examined for their ability to secrete the cell wall-degrading enzymes chitinase, beta-1,3-glucanase, and cellulase, to parasitize sclerotia of Sclerotium rolfsii, to reduce bean stem rot caused by S. rolfsii, and to secrete antifungal substance(s) active against Verticillium dahliae. The benomyl-resistant mutant Ben(R)TF1-R6 overproduced extracellular enzymes and exhibited enhanced antagonistic activity against S. rolfsii and V. dahliae compared to the wild-type strains and other mu tants. Correlation analyses between the extracellular enzymatic activities of different isolates of T. flavus and their ability to antagonize S. rolfsii indicated that mycoparasitism by T. flavus and biological control of S rolfsii were related to the chitinase activity of T. flavus. On the other hand, production of antifungal compounds and glucose-oxidase activity may play a role in antagonism of V. dahliae by retardation of germination and hyphal growth and melanization of newly formed microsclerotia.

  3. Isolation and characterization of putative endophytic bacteria antagonistic to Phoma tracheiphila and Verticillium albo-atrum.

    Science.gov (United States)

    Kalai-Grami, Leila; Saidi, Sabrine; Bachkouel, Sarra; Ben Slimene, Imen; Mnari-Hattab, Monia; Hajlaoui, Mohamed Rebah; Limam, Ferid

    2014-09-01

    A collection of 200 bacterial isolates recovered from citrus plants (Citrus limon, Citrus sinensis, and Citrus reticulata), Medicago truncatula and Laurus nobilis, was established. In vitro screening indicated that 28 isolates exhibited an inhibitory activity against the vascular pathogens Phoma tracheiphila and Verticillium albo-atrum. Isolates were screened according to their hydrolytic activities, plant growth-promoting bacteria (PGPB) abilities, as well as for the presence of nonribosomal peptide synthetase (NRPS) genes responsible of the lipopeptide biosynthesis. The results were positive for 16 isolates which exhibited at least two PGPB activities and a single NRPS gene. Genetic diversity of the selected isolates was studied using random amplified polymorphic DNA (RAPD) and repetitive element PCR (REP) tools that showed clustering of strains into three major groups (I, II, and III) (i, ii, and iii), respectively. Clustering was further confirmed by the 16S rDNA sequencing that assigned nine isolates to Bacillus velezensis, four isolates to Bacillus methyltrophicus, one isolate to Bacillus amyloliquefaciens, and two isolates to Bacillus mojavensis. Organ-bacterial genotype interaction as well as positive correlation with NRPS genes are discussed.

  4. [Construction and analysis of SSH library of Gossypium barbadense upon infection with Verticillium dahliae].

    Science.gov (United States)

    Zhu, Long-Fu; Tu, Li-Li; Zhang, Xian-Long; Nie, Yi-Chun; Guo, Xiao-Ping; Xia, Qi-Zhong

    2005-05-01

    Roots were collected from the seedlings inoculated with pathogen Verticillium dahliae after 2, 4, 8, 12, 24, 48, 72 and 96 hours for total RNA extraction. The cDNAs from the inoculated seedlings were used as the tester and those from the control seedlings as the driver. SSH method was employed to find the differently expressed cDNAs responding to the pathogen. T/A clone library was constructed containing 534 clones. The cDNA inserts were amplified from the bacterial clones directly with M13 primers by PCR. The size of the products ranged 0.2 - 1.2 kb with an average size of 0.5 kb. The SSH products were dotted on nylon filters, and the positive clones were screened by virtual Northern blotting with probes of the two kinds of initiative cDNAs. Totally 78 clones which were up-regulated and putatively involved in the defense response of G. barbadense were identified and sequenced. Sequence similarity searches were performed with the Blastn and Blastx. Most of them showed high or partial homology to genes or ESTs induced by different stresses in Arabidopsis thaliana and other species,such as the pathogenesis-related 10 family of G. hirsumtum and disease resistance-responsive family protein in Arabidopsis thaliana. The results would be helpful to understand the molecular mechanisms of disease response in cotton.

  5. Detection of laurel wilt disease in avocado using low altitude aerial imaging.

    Science.gov (United States)

    de Castro, Ana I; Ehsani, Reza; Ploetz, Randy C; Crane, Jonathan H; Buchanon, Sherrie

    2015-01-01

    Laurel wilt is a lethal disease of plants in the Lauraceae plant family, including avocado (Persea americana). This devastating disease has spread rapidly along the southeastern seaboard of the United States and has begun to affect commercial avocado production in Florida. The main objective of this study was to evaluate the potential to discriminate laurel wilt-affected avocado trees using aerial images taken with a modified camera during helicopter surveys at low-altitude in the commercial avocado production area. The ability to distinguish laurel wilt-affected trees from other factors that produce similar external symptoms was also studied. RmodGB digital values of healthy trees and laurel wilt-affected trees, as well as fruit stress and vines covering trees were used to calculate several vegetation indices (VIs), band ratios, and VI combinations. These indices were subjected to analysis of variance (ANOVA) and an M-statistic was performed in order to quantify the separability of those classes. Significant differences in spectral values among laurel wilt affected and healthy trees were observed in all vegetation indices calculated, although the best results were achieved with Excess Red (ExR), (Red-Green) and Combination 1 (COMB1) in all locations. B/G showed a very good potential for separate the other factors with symptoms similar to laurel wilt-affected trees, such as fruit stress and vines covering trees, from laurel wilt-affected trees. These consistent results prove the usefulness of using a modified camera (RmodGB) to discriminate laurel wilt-affected avocado trees from healthy trees, as well as from other factors that cause the same symptoms and suggest performing the classification in further research. According to our results, ExR and B/G should be utilized to develop an algorithm or decision rules to classify aerial images, since they showed the highest capacity to discriminate laurel wilt-affected trees. This methodology may allow the rapid detection

  6. Effects of wilting and molasses addition on fermentation and bacterial community in guinea grass silage.

    Science.gov (United States)

    Nishino, N; Li, Y; Wang, C; Parvin, S

    2012-03-01

    Acetic acid is considered an important preservative in tropical grass ensiling. The objective of the current experiments was to follow the ensiling fermentation of low dry matter (DM) tropical grass as a model to study changes in bacterial communities during acetic acid fermentation. Direct-cut and wilted guinea grass silage was prepared with and without molasses. A high acetic acid level was observed during the fermentation of direct-cut silage, and long storage increased the butyric acid and ethanol content if molasses was not added. The lactic acid production in wilted silage was greater than the acetic acid production, but prolonged ensiling decreased the lactic to acetic acid ratio regardless of molasses addition. Adding molasses enhanced the lactic acid content in both direct-cut and wilted silage. The bacterial community, identified by denaturing gradient gel electrophoresis, was affected by wilting and molasses addition. Bands for Pantoea sp. and Morganella sp. became faint when acetic acid fermentation was suppressed, and those for Pediococcus pentosaceus and Lactococcus garvieae were detected when lactic acid fermentation was enhanced by wilting and molasses addition. Lactobacillus plantarum and Lactococcus lactis were found throughout the ensiling process in all silage types. Distinct changes occurred in the bacterial community in guinea grass silage because of wilting and molasses addition. These changes could explain how lactic acid fermentation was enhanced but could not help determine which bacteria were associated with enhanced acetic acid fermentation. The study reveals the effects of wilting and molasses during ensiling of low DM tropical grasses and the associated bacteria. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

  7. Onderstammen voor de biologische teelt van vruchtgroenten : inventarisatie van resistente onderstammen van komkommer en paprika voor Meiloidogyne spp. en Verticillium dahliae

    NARCIS (Netherlands)

    Labrie, C.W.

    2008-01-01

    A literature study has been carried out about resistance and tolerance of cucumber and sweet pepper rootstocks to Meloidogyne spp. and Verticillium dahliae. This study offers an overview of research in practice and international scientific literature. For cucumber no rootstocks are known that are

  8. Inheritance and variability of tolerance to Verticillium dahliae Kleb amoung geographically remote F1-F2 hybrids of Gossypium hirsutum L.

    Science.gov (United States)

    One of the most important problems for cotton breeding in Uzbekistan is development of Verticillium dahliae tolerant varieties. One approach is to utilize ecologically remote intraspecific and interspecific hybridization with local commercial cultivars. To this end, we have conducted genetically b...

  9. Morphology of Verticillium dahliae and V. tricorpus on semi-selective media used for the detection of V. dahliae in soil

    NARCIS (Netherlands)

    Goud, J.C.; Termorshuizen, A.J.; Gams, W.

    2003-01-01

    The morphology of two soil-borne Verticillium species, V. dahliae and V. tricorpus, was studied on two semi-selective agar media, in the absence and presence of soil. Morphology of the fungi differed considerably between the media, with respect to presence and shape of microsclerotia, dark hyphae

  10. Long-term effects of eight soil health treatments to control plant-parasitic nematodes and Verticillium dahliae in agro-ecosystems

    NARCIS (Netherlands)

    Korthals, G.W.; Thoden, T.C.; Berg, van den W.; Visser, J.H.M.

    2014-01-01

    There is an urgent need to test and develop sustainable methods for management of soil pathogens, such as the root-lesion nematode Pratylenchus penetrans and the soil fungus Verticillium dahliae. Ultimately this should be investigated with a multidisciplinary approach, with long-term measurements of

  11. Late summer disease symptoms in western Washington red raspberry fields associated with co-occurrence of Phytophthora rubi, Verticillium dahliae, and Pratylenchus penetrans

    Science.gov (United States)

    60% of the $109 million processed by the U.S. red raspberry industry is in northern Washington. In 2012, late summer disease symptoms were observed in many raspberry fields. These symptoms were initially attributed to Verticillium dahliae, but other soilborne pathogens (Phytophthora rubi, Pratylench...

  12. Bacterial community dynamics during the ensilage of wilted grass.

    Science.gov (United States)

    McEniry, J; O'Kiely, P; Clipson, N J W; Forristal, P D; Doyle, E M

    2008-08-01

    Grass silage is the product formed by a natural lactic acid bacterial fermentation when grass is stored under anaerobic conditions, and represents an important ruminant feedstuff on farms during winter. Of the two commonly employed methods of ensiling forage, baled silage composition frequently differs from that of comparable precision-chop silage reflecting a different ensiling environment. The aim of this study was to investigate the dynamics of the silage fermentation in wilted grass and between ensiling systems. Fermentation dynamics were examined using traditional methods of silage analyses, including microbial enumeration and analysis of fermentation products, and culture-independent terminal restriction fragment length polymorphism (T-RFLP). A successful fermentation was achieved in both systems, with the fermentation (increase in lactic acid bacteria and lactic acid concentration, decrease in pH) proceeding rapidly once the herbage was ensiled. Under controlled conditions, little difference in silage quality and microbial composition were observed between ensiling systems and this was further reflected in the T-RFLP community analysis. T-RFLP proved a potentially useful tool to study the ensilage process and could provide valid support to traditional methods, or a viable alternative to these methods, for investigating the dynamics of the bacterial community over the course of the fermentation.

  13. Phylogenetic and recombination analysis of tomato spotted wilt virus.

    Directory of Open Access Journals (Sweden)

    Sen Lian

    Full Text Available Tomato spotted wilt virus (TSWV severely damages and reduces the yield of many economically important plants worldwide. In this study, we determined the whole-genome sequences of 10 TSWV isolates recently identified from various regions and hosts in Korea. Phylogenetic analysis of these 10 isolates as well as the three previously sequenced isolates indicated that the 13 Korean TSWV isolates could be divided into two groups reflecting either two different origins or divergences of Korean TSWV isolates. In addition, the complete nucleotide sequences for the 13 Korean TSWV isolates along with previously sequenced TSWV RNA segments from Korea and other countries were subjected to phylogenetic and recombination analysis. The phylogenetic analysis indicated that both the RNA L and RNA M segments of most Korean isolates might have originated in Western Europe and North America but that the RNA S segments for all Korean isolates might have originated in China and Japan. Recombination analysis identified a total of 12 recombination events among all isolates and segments and five recombination events among the 13 Korea isolates; among the five recombinants from Korea, three contained the whole RNA L segment, suggesting reassortment rather than recombination. Our analyses provide evidence that both recombination and reassortment have contributed to the molecular diversity of TSWV.

  14. Reproducibility of suppression of Pythium wilt of cucumber by compost

    Directory of Open Access Journals (Sweden)

    Mauritz Vilhelm Vestberg

    2014-10-01

    Full Text Available There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v. Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009, indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.

  15. Genetically engineered bananas resistant to Xanthomonas wilt disease and nematodes.

    Science.gov (United States)

    Tripathi, Leena; Atkinson, Howard; Roderick, Hugh; Kubiriba, Jerome; Tripathi, Jaindra N

    2017-05-01

    Banana is an important staple food crop feeding more than 100 million Africans, but is subject to severe productivity constraints due to a range of pests and diseases. Banana Xanthomonas wilt caused by Xanthomonas campestris pv. musacearum is capable of entirely destroying a plantation while nematodes can cause losses up to 50% and increase susceptibility to other pests and diseases. Development of improved varieties of banana is fundamental in order to tackle these challenges. However, the sterile nature of the crop and the lack of resistance in Musa germplasm make improvement by traditional breeding techniques either impossible or extremely slow. Recent developments using genetic engineering have begun to address these problems. Transgenic banana expressing sweet pepper Hrap and Pflp genes have demonstrated complete resistance against X. campestris pv. musacearum in the field. Transgenic plantains expressing a cysteine proteinase inhibitors and/or synthetic peptide showed enhanced resistance to a mixed species population of nematodes in the field. Here, we review the genetic engineering technologies which have potential to improve agriculture and food security in Africa.

  16. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture

    Science.gov (United States)

    Álvarez, Belén; Biosca, Elena G.

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis, not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta. Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field. PMID:28769942

  17. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture.

    Science.gov (United States)

    Álvarez, Belén; Biosca, Elena G

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis, not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta. Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field.

  18. The xylem as battleground for plant hosts and vascular wilt pathogens

    Directory of Open Access Journals (Sweden)

    Koste eYadeta

    2013-04-01

    Full Text Available Vascular wilts are among the most destructive plant diseases that occur in annual crops as well as in woody perennials. These diseases are generally caused by soil-borne bacteria, fungi and oomycetes that infect through the roots and enter the water-conducting xylem vessels where they proliferate and obstruct the transportation of water and minerals. As a consequence, leaves wilt and die, which may lead to impairment of the whole plant and eventually to death of the plant. Cultural, chemical and biological measures to control this group of plant pathogens are generally ineffective, and the most effective control strategy is the use of genetic resistance. Owing to the fact that vascular wilt pathogens live deep in the interior of their host plants, studies into the biology of vascular pathogens are complicated. However, to design novel strategies to combat vascular wilt diseases, understanding the (molecular biology of vascular pathogens and the molecular mechanisms underlying plant defense against these pathogens is crucial. In this review we discuss the current knowledge on interactions of vascular wilt pathogens with their host plants, with emphasis on host defense responses against this group of pathogens.

  19. Rhizobacteria induces resistance against Fusarium wilt of tomato by increasing the activity of defense enzymes

    Directory of Open Access Journals (Sweden)

    Hélvio Gledson Maciel Ferraz

    2014-09-01

    Full Text Available Fusarium wilt, caused by Fusarium oxysporum f.sp. lycopersici (Fol, is one of the most important diseases that affect tomato yield worldwide. This study investigated the potential of three antagonists, Streptomyces setonii (UFV 618, Bacillus cereus (UFV 592 and Serratia marcescens (UFV 252, and as positive control the hormone jasmonic acid (JA, to reduce Fusarium wilt symptoms and to potentiate the defense enzymes in the stem tissues of tomato plants infected by Fol. The seeds were microbiolized with each antagonist, and the soil was also drenched with them. The plants were sprayed with JA 48 h before Fol inoculation. The area under the Fusarium wilt index progress curve was reduced by 54, 48, 47 and 45% for the UFV 618, JA, UFV 592 and UFV 252 treatments, respectively. The three antagonists, and even the JA spray, efficiently reduced the Fusarium wilt symptoms on the tomato plant stems, which can be explained by the lower malondialdehyde concentration (an indication of oxidative damage to lipids in the plasma membranes and the greater activities of peroxidases, polyphenoloxidases, glucanases, chitinases, phenylalanine ammonia-lyases and lipoxygenases, which are commonly involved in host resistance against fungal diseases. These results present a novel alternative that can be used in the integrated management of Fusarium wilt on tomatoes.

  20. Molecular identification of Fusarium spp. causing wilt of chickpea and the first report of Fusarium redolens in Turkey

    Science.gov (United States)

    Chickpea (Cicer arietinum L.) is an important food legume crop and Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris is one of the most important diseases of chickpea in Turkey. Fusarium redolens is known to cause wilt-like disease of chickpea in other countries, but has not been reported fr...

  1. Effector gene suites in some soil isolates of Fusarium oxysporum are not sufficient predictors of vascular wilt in tomato

    Science.gov (United States)

    This is the first study examining the distribution of fungal effector genes among soil populations of Fusarium oxysporum in a tomato field undergoing a wilt disease epidemic. 74 F. oxysporum soil isolates were assayed for known effector genes present in a Race 3 tomato wilt strain (FOL MN-25) obtain...

  2. Meta-analysis to refine map position and reduce confidence intervals for delayed canopy wilting QTLs in soybean

    Science.gov (United States)

    Slow canopy wilting in soybean has been identified as a potentially beneficial trait for ameliorating drought effects on yield. Previous research identified QTLs for slow wilting from two different bi-parental populations and this information was combined with data from three other populations to id...

  3. Identification of Genes Induced in Lolium multiflorum by Bacterial Wilt Infection

    DEFF Research Database (Denmark)

    Wichmann, Fabienne; Asp, Torben; Widmer, Franco

    2010-01-01

    Xanthomonas translucens pv. graminis(Xtg) causes bacterial wilt in many forage grasses including Italian ryegrass (Lolium multiflorum Lam), seriously reducing yield and quality. Breeding for resistance is currently the only practicable means of disease control. Molecular markers closely linked...... to resistance genes or QTL could complement and support phenotypic selection. We used comparative gene expression analysis of a partially resistant L. multiflorum genotype infected and not infected with Xtg to identify genes involved in the control of resistance to bacterial wilt. The genes differentially...... expressed upon infection will serve as the basis for the identification of key genes involved in bacterial wilt resistance and to develop molecular markers for marker assisted breeding. Fluorescently labelled cDNA prepared from plant leaves collected at four different time points after infection...

  4. Improving Control of Fusarium Wilt of Leguminous Plants by Combined Application of Biocontrol Agents

    Directory of Open Access Journals (Sweden)

    O.A. Abdul Wahid

    2006-12-01

    Full Text Available In dual culture tests, Trichoderma pseudokoningii and Bacillus subtilis parasitized and inhibited the growth of Fusarium oxysporum f. sp. fabae and of F. oxysporum f. sp. lupini, which cause wilt on broad bean and lupine respectively. When applied to the seeds of these crops in field experiments, both antagonists controlled wilt of broad bean and lupine (75.2% healthy plants. A mixture of both biocontrol agents was more effective than either agent used alone. Moreover, the biocontrol agents provided a higher percentage of healthy plants than a fungicide tested for comparison. Fresh filtrate of both antagonists was more effective in suppressing pathogen growth than stored filtrate.

  5. EVALUATION OF LENTIL GERMPLASM FOR DISEASE RESISTANCE TO FUSARIUM WILT (FUSARIUM OXYSPORUM F.SP. LENTIS

    Directory of Open Access Journals (Sweden)

    Tzvetelina Stoilova

    2006-10-01

    Full Text Available Lentil (Lens culinaris Medic. is one of the oldest known protein-rich food legumes. Lentil is the second pulse crop after dry bean in Bulgaria. Diseases such as Ascochyta blight and Lentil wilt play a major role in reducing lentil yield. Thirty two lentil genotypes with different geographical origin were screened for reaction to Fusarium oxysporum f.sp. lentis during 2003-2004 from the Institute for Plant Genetic Resourses, Sadovo under greenhouse conditions. Three of the studied accessions (91-001, 91-028 and 98-001 were susceptible with 45 and 50 % of total wilted plant.

  6. Screening of Tomato Cultivars for Resistance to Pulsarium Wilt in Eastern States of Nigeria

    Directory of Open Access Journals (Sweden)

    M. Y. Nwaiwu

    2013-12-01

    Full Text Available The causual organism of the out-break of wilt disease of tomato in the Imo and Rivers States of Nigeria was identified as Fusarium pallindoroseum (Berk and Rav Booth and Sutton, and its pathogenicity was established. Experiments were designed to screen five tomato cultivars for resistance to F. pallidoroseum. Four methods were employed in the screening experiments. The results of all the methods used showed the cultivar IFe-l as the most susceptible (65 % while the Chef Cultivar was the most resistant with less than 10 % of the test plants wilting.

  7. Bidirectional promoter trapping T-DNA for insertional mutagenesis in Verticillium dahliae.

    Science.gov (United States)

    Deng, Sheng; Wang, Cai-yue; Zhang, Xin; Lin, Ling

    2014-07-01

    Transfer DNA (T-DNA)-based random insertional mutagenesis is a universal forward genetic approach for gene identification and cloning in many phytopathogenic fungi. In a large number of randomly selected transformants, screening for mutants with a specific phenotype is laborious, especially for pathogenicity-defective mutants. To accelerate mutant screening and gene identification, a bidirectional promoter-trapping Ti binary vector, 1300-bisGFP-hyg, was constructed and deployed in this study. More than 6000 Verticillium dahliae transformants were obtained by the mediation of Agrobacterium tumefaciens carrying the vector. One thousand randomly selected transformants were cultured on Czapek-Dox and on Czapek-Dox plus cotton root extract media plates. The cultured transformants with green fluorescent protein (GFP) expression or changes in phenotype were selected and used in virulence or promoter-trapping assays. Based on the virulence assay of 60 transformants, the pathogenicity of 17 of these mutants was compromised. Ten pathogenicity-defective mutants were found with GFP expression, and 6 with expression in Czapek-Dox plus cotton root extract media specifically. Using TAIL-PCR (thermal asymmetric interlaced polymerase chain reaction), the T-DNA insertion sites were identified in 8 GFP-expressing transformants, including 5 pathogenicity-defective mutants and 3 unaffected transformants. Promoters of 6 genes were successfully trapped using the T-DNA method in this study. The nonpathogenic transformant 24C9 was the subject of additional investigation. It displayed strong GFP expression on water agar medium supplemented with cotton root extracts and on cotton seedling stems. The results obtained by Southern blot and quantitative real-time PCR confirmed that the transcription level of VdUGPU (encoding UTP-glucose-1-phosphate uridylyltransferase) was significantly reduced owing to T-DNA insertion in the gene promoter region. These results indicate that the bidirectional

  8. Ozone and Eusarium: effects on the growth and development of a wilt-susceptible tomato and a wilt-resistant tomato

    Energy Technology Data Exchange (ETDEWEB)

    Manning, W.J.; Vardaro, P.M.

    1976-01-01

    Seedlings of tomato (Lycopersicon esculentum Mill.) cultivars Rutgers (Fusarium-susceptible) and Supersonic (Fusarium-resistant) were transplanted into 20 cm diam. pots of either steamed soil or steamed soil infested with Fusarium oxysporum f. sp. lycopersici (race 1) and grown for 45 days in 2 paired greenhouses. One contained charcoal-filtered air and the other filtered air plus ozone at 0.06-0.08 ppm for 6 hr/day 5 day/week. Slight to moderate white stippling was observed on the older leaves of all plants exposed to ozone. Fusarium wilt symptoms were noted in Rutgers plants grown in filtered air 14-18 days before they were noted in comparable plants exposed to ozone. Symptom expression and death of plants progressed more rapidly in filtered air. Ozone retarded growth and delayed wilt symptoms in Rutgers plants. Supersonic plants did not develop wilt symptoms, but fusarium significantly reduced (P=0.05) root and top dry weights of plants grown in filtered air. Plant height and root and top dry weights for Supersonic plants in Fusarium-infested soil were further significantly (P-0.05) reduced by ozone. Ozone and Fusarium, singly or together in an additive manner, significantly reduced the growth and development of a Fusarium-resistant tomato.

  9. Evaluation of Alternatives to Carbamate and Organophosphate Insecticides Against Thrips and Tomato Spotted Wilt Virus in Peanut Production.

    Science.gov (United States)

    Marasigan, K; Toews, M; Kemerait, R; Abney, M R; Culbreath, A; Srinivasan, R

    2016-04-01

    Thrips are important pests of peanut. They cause severe feeding injuries on peanut foliage in the early season. They also transmit Tomato spotted wilt virus (TSWV), which causes spotted wilt disease. At-plant insecticides and cultivars that exhibit field resistance to TSWV are often used to manage thrips and spotted wilt disease. Historically, peanut growers used the broad-spectrum insecticides aldicarb (IRAC class 1A; Temik) and phorate (IRAC class 1B; Thimet) for managing thrips and thereby reducing TSWV transmission. Aldicarb has not been produced since 2011 and its usage in peanut will be legally phased out in 2018; therefore, identification of alternative chemistries is critical for thrips and spotted wilt management. Here, eight alternative insecticides, with known thrips activity, were evaluated in field trials conducted from 2011 through 2013. In addition, different application methods of alternatives were also evaluated. Imidacloprid (Admire Pro), thiamethoxam (Actara), spinetoram (Radiant), and cyantraniliprole (Exirel) were as effective as aldicarb and phorate in suppressing thrips, but none of the insecticides significantly suppressed spotted wilt incidence. Nevertheless, greenhouse assays demonstrated that the same alternative insecticides were effective in suppressing thrips feeding and reducing TSWV transmission. Spotted wilt incidence in the greenhouse was more severe (∼80%) than in the field (5–25%). In general, field resistance to TSWV in cultivars only marginally influenced spotted wilt incidence. Results suggest that effective management of thrips using alternative insecticides and subsequent feeding reduction could improve yields under low to moderate virus pressure.

  10. Plant growth-promoting rhizobacteria strain Bacillus amyloliquefaciens NJN-6-enriched bio-organic fertilizer suppressed Fusarium wilt and promoted the growth of banana plants.

    Science.gov (United States)

    Yuan, Jun; Ruan, Yunze; Wang, Beibei; Zhang, Jian; Waseem, Raza; Huang, Qiwei; Shen, Qirong

    2013-04-24

    Bacillus amyloliquefaciens strain NJN-6 is an important plant growth-promoting rhizobacteria (PGPR) which can produce secondary metabolites antagonistic to several soil-borne pathogens. In this study, the ability of a bio-organic fertilizer (BIO) containing NJN-6 strain to promote the growth and suppress Fusarium wilt of banana plants was evaluated in a pot experiment. The results showed that the application of BIO significantly decreased the incidence of Fusarium wilt and promoted the growth of banana plants compared to that for the organic fertilizer (OF). To determine the beneficial mechanism of the strain, the colonization of NJN-6 strain on banana roots was evaluated using scanning electron microscopy (SEM). The plant growth-promoting hormones indole-3-acetic acid (IAA) and gibberellin A3 (GA3), along with antifungal lipopeptides iturin A, were detected when the NJN-6 strain was incubated in both Landy medium with additional l-tryptophan and in root exudates of banana plants. In addition, some antifungal volatile organic compounds and iturin A were also detected in BIO. In summary, strain NJN-6 could colonize the roots of banana plants after the application of BIO and produced active compounds which were beneficial for the growth of banana plants.

  11. Western flower thrips can transmit Tomato spotted wilt virus from infected tomato fruits

    Science.gov (United States)

    Tomato spotted wilt virus (TSWV) has long been known to spread via plant propagation materials including transplants. Global dissemination of TSWV has also been linked to transport of thrips-infested and virus-infected horticultural and floricultural products through trade and commerce. However, th...

  12. Western flower thrips can transmit Tomato spotted wilt virus from virus-infected tomato fruits

    Science.gov (United States)

    Acquisition and transmission of Tomato spotted wilt virus from symptomatic tomato fruits by western flower thrips was demonstrated for the first time. This suggests that infected tomato fruits may be a source of virus and also provide an additional means of virus movement between geographic areas....

  13. Water Extract from Spent Mushroom Substrate of Hericium erinaceus Suppresses Bacterial Wilt Disease of Tomato

    OpenAIRE

    Kwak, A Min; Min, Kyeong Jin; Lee, Sang Yeop; Kang, Hee Wan

    2015-01-01

    Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium caro...

  14. On-farm successes and challenges of producing bacterial wilt-free ...

    African Journals Online (AJOL)

    Shortage, unavailability and high cost of disease-free seed potato and Ralstonia solanacearum-infested soils have remained key limitations in the management of potato bacterial wilt in Kenya. Attempts to reduce yield losses caused by the disease have been made through on-farm development and promotion of a ...

  15. evaluation of enset clones against enset bacterial wilt abstract résumé

    African Journals Online (AJOL)

    jen

    Sidama, Gurage, Kembata Tembaro and Hadyia zones were assessed for resistance/tolerance to enset bacterial .... enset bacterial wilt. MATERIALS AND METHODS. Assessing enset clones from the Gurage,. Hadyia, Kembata Tembaro and Sidama zones. A total of 103 enset ..... genetic diversity and crop ecology of enset.

  16. Tomato spotted wilt virus Gc and N proteins interact in vivo

    NARCIS (Netherlands)

    Snippe, M.; Borst, J.W.; Goldbach, R.W.; Kormelink, R.J.M.

    2007-01-01

    Tomato spotted wilt virus (TSWV) virions consist of a nucleocapsid core surrounded by a membrane containing glycoproteins Gn and Gc. To unravel the protein interactions involved in the membrane acquisition of RNPs, TSWV nucleocapsid protein (N), Gn and Gc were expressed and analyzed in BHK21 cells.

  17. Towards the development of a laurel wilt screening program in redbay (Persea borbonia)

    Science.gov (United States)

    Marc Hughes; Jason Smith

    2012-01-01

    Laurel wilt is a highly destructive disease of redbay (Persea borbonia (L.) Spreng.) and other Lauraceous natives in the southeastern United States. The disease and associated vector, the redbay ambrosia beetle (Xyleborus glabratus), has spread through the United States coastal plain. The presence of surviving and...

  18. APPLICATION OF PROPICONAZOLE IN MANAGEMENT OF LAUREL WILT DISEASE IN AVOCADO (Persea americana Mill.) TREES

    Science.gov (United States)

    Laurel wilt is a vascular disease of Lauraceous plants caused by a fungus (Raffaelea spp.) that is carried by a recently introduced, nonnative ambrosia beetle (Xyleborus glabratus). The disease is devastating to Persea species including redbay (Persea borbonia) and avocado (Persea americana) trees i...

  19. Tomato spotted wilt virus in Sri Lanka: Emerging problems of Tospovirues

    NARCIS (Netherlands)

    Widana Gamage, S.M.K.; Hassani Mehraban, A.; Peters, D.

    2015-01-01

    Tomato spotted wilt virus (TSWV), the type species of the genus Tospovirus has long been reported infecting economically important horticultural crops such as tomato, groundnut, pepper, potato and soybean, all over the world. In Sri Lanka, characteristic tospovirus symptoms such as bud necrosis,

  20. Evaluation of thrips resistance in pepper to control Tomato spotted wilt virus infection

    NARCIS (Netherlands)

    Maris, P.C.

    2004-01-01

    The objective of this study was to analyse the effect of thrips ( F. occidentalis ) resistance in pepper ( Capsicum ) on the spread of Tomato spotted wilt virus (TSWV). Results demonstrate that the rate of primary TSWV-infection is effectively limited in a thrips-resistant (TR) pepper crop compared

  1. Aerial remote sensing survey of Fusarium wilt of cotton in New Mexico and Texas

    Science.gov (United States)

    Fusarium wilt of cotton, caused by the fungus Fusarium oxysporum f. sp. vasinfectum (FOV), is a widespread cotton disease, but the more virulent FOV race 4 (FOV4) has recently been identified in the New Mexico-Texas border area near El Paso, Texas. A preliminary aerial remote sensing survey was cond...

  2. Semiochemical-mediated flight responses of sap beetle vectors of oak wilt, Ceratocystis fagacearum

    Science.gov (United States)

    John F. Kyhl; Robert J. Bartelt; Allard Cosse; Jennifer Juzwik; Steven J. Seybold

    2002-01-01

    The sap beetle, Colopterus truncatus (Coleoptera: Nitidulidae), is one of the primary vectors of the oak wilt pathogen, Ceratocystis fagacearum, in the north-central United States. Field behavioral assays utilizing various release rates and blends of three methyl-branched hydrocarbon aggregation pheromone components showed that...

  3. Stem nematode-fusarium wilt complex in alfalfa as related to irrigation management at harvest time.

    Science.gov (United States)

    Griffin, G D

    1992-06-01

    A high moisture level in the top 10 cm of soil at time of cutting of alfalfa increased the incidence of plant mortality and Fusarium wilt in soil infested with Ditylenchus dipsaci and Fusarium oxysporum f. sp. medicaginis in greenhouse and field microplot studies. Ranger alfalfa, susceptible to both D. dipsaci and F. oxysporum f. sp. medicaginis, was less persistent than Moapa 69 (nematode susceptible and Fusarium wilt resistant) and Lahontan alfalfa (nematode resistant with low Fusarium wilt resistance). In the greenhouse, the persistence of Ranger, Moapa 69, and Lahontan alfalfa plants was 46%, 64%, and 67% respectively, in nematode + fungus infested soil at high soil moisture at time of cutting. This compared to 74%, 84%, and 73% persistence of Ranger, Moapa 69, and Lahontan, respectively, at low soil moisture at time of cutting. Shoot weights as a percentage of uninoculated controls at the high soil moisture level were 38%, 40%, and 71% for Ranger, Moapa 69, and Lahontan, respectively. Low soil moisture at time of cutting negated the effect D. dipsaci on plant persistence and growth of subsequent cuttings, and reduced Fusarium wilt of plants in the nematode-fungus treatment; shoot weights were 75%, 90%, and 74% of uninoculated controls for Ranger, Moapa 69, and Lahontan. Similar results were obtained in the field microplot study, and stand persistence and shoot weights were less in nematode + fungus-infested soil at the high soil-moisture level (early irrigation) than at the low soil-moisture level (late irrigation).

  4. Bio-fertilizer application induces soil suppressiveness against Fusarium wilt disease by reshaping the soil microbiome

    NARCIS (Netherlands)

    Wu, Xiong|info:eu-repo/dai/nl/41357668X; Guo, Sai; Jousset, Alexandre|info:eu-repo/dai/nl/370632656; Zhao, Qingyun; Wu, Huasong; Li, Rong; Kowalchuk, George A.|info:eu-repo/dai/nl/23956006X; Shen, Qirong

    2017-01-01

    Fusarium wilt disease is a growing problem in agriculture systems. Application of bio-fertilizers containing beneficial microbes represents a promising disease control strategy. However, the mechanisms underlying disease suppression remain elusive. Here, in order to assess the importance of direct

  5. Vertical distribution and daily flight periodicity of ambrosia beetles associated with laurel wilt affected avocado orchards.

    Science.gov (United States)

    Recently, ambrosia beetles have emerged as significant pests of avocado (Persea americana Mill.; Lauraceae) due to their association with fungal pathogens, in particular, the causal agent of laurel wilt disease, Raffaelea lauricola. The objective of this study was to provide insights into the intera...

  6. Impact of soil amendments and weather factors on bacterial wilt and ...

    African Journals Online (AJOL)

    Tomato bacterial wilt, caused by Ralstonia solanacearum, leads to tomato yield losses of up to 80% in southwestern Nigeria. Soil amendments and weather conditions are important in the management of the disease. Field experiments were conducted at the Research Farm of the Federal University of Agriculture, Abeokuta, ...

  7. Genetic diversity, virulence, and Meloidogyne incognita interactions of Fusarium oxysporum isolates causing cotton wilt in Georgia

    Science.gov (United States)

    Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. ox...

  8. Factors associated with Leguminous Green Manure Incorporation and Fusarium wilt suppression in watermelon

    Science.gov (United States)

    A fall planted Vicia villosa cover crop incorporated in spring as a green manure can suppress Fusarium wilt [Fusarium oxysporum f. sp. niveum (FON)] of watermelon in Maryland and Delaware. Experiments were conducted to determine whether the mechanism of this suppression was general or specific, and ...

  9. Impact of five cover crop green manures and Actinovate on Fusarium Wilt of watermelon

    Science.gov (United States)

    Triploid watermelon cultivars are grown on more than 2,023 ha in Maryland and in Delaware. Triploid watermelons have little host resistance to Fusarium wilt of watermelon (Fusarium oxysporum f. sp. niveum). The effects of four different fall-planted cover crops that were tilled in the spring as gree...

  10. Characterization of two biologically distinct variants of Tomato spotted wilt virus

    Science.gov (United States)

    Significant economic losses result on a wide range of crops due to infection with Tomato spotted wilt virus (TSWV). In this study, two TSWV isolates, one from basil and a second from tomato, were established in a common plant host. Viral proteins were monitored over time, plant host ranges were comp...

  11. Evaluation of bio-agent formulations to control Fusarium wilt of tomato

    African Journals Online (AJOL)

    The ED50 value of antagonistic substance from Chaetomium globosum N0802 extracted with hexane was 157 μg/ml. This gave the highest inhibition of conidial production of Fusarium oxysporum f. sp. lycopersici causing tomato wilt var Sida. Crude hexane from Chaetomium lucknowense CLT and crude methanol from ...

  12. Ranking of grass species according to visible wilting order and rate ...

    African Journals Online (AJOL)

    The leaf water potential and soil water content at which each grass species wilted were recorded. Keywords: availability; digitaria argyrograpta; digitaria eriantha; grasses; leaf water potential; moisture stress; neutron probe; orange free state; panicum stapfianum; soil water; soil water content; soil water potential; south africa ...

  13. The xylem as battleground for plant hosts and vascular wilt pathogens

    NARCIS (Netherlands)

    Yadeta, K.A.; Thomma, B.P.H.J.

    2013-01-01

    Vascular wilts are among the most destructive plant diseases that occur in annual crops as well as in woody perennials. These diseases are generally caused by soil-borne bacteria, fungi, and oomycetes that infect through the roots and enter the water-conducting xylem vessels where they proliferate

  14. Biological Control of Fusarium Wilt of Tomato – A Review | Monda ...

    African Journals Online (AJOL)

    Fusarium wilt of tomato (Lycopersicum esculentum) caused by Fusarium oxysporum f.sp. lycopersici leads to high losses of tomatoes in many countries. Increasing restraints on the use of pesticides encourages adoption of use of alternative strategies of controlling the disease. Alternative strategies include use of biocontrol ...

  15. Silage of white oat under nitrogen fertilization and pre-wilting

    Directory of Open Access Journals (Sweden)

    Gustavo Zamarchi

    2014-09-01

    Full Text Available The forage conservation as silage is a way to provide good quality forage during grazing scarcity periods, in this way, the objective was to evaluate the effect of pre-wilting and nitrogen fertilization on the fermentation characteristics and nutritive value of white oat silage, in two harvest stages. The experiment was conducted in 2011 at UTFPR, Dois Vizinhos-PR, Brazil. The experimental design was in a randomized blocks with two factorial arrangement and three replicates. The main treatments were six nitrogen doses: 0, 40, 80, 120, 160 and 200 kg ha-1, and secondary the stages of cutting for silage: early flowering with and without pre-wilting, and at blooming without pre-wilting. It was observed that nitrogen fertilization promoted a reduction in pH and mineral content of the silage, reducing fiber content and increasing crude protein content (CP, when made at oat early flowering. The effect of pre-wilting in early flowering inhibits the production of effluents and has higher levels of CP, without any effect on the fermentation and nutritional value. The silage at blooming stage features better standards of fermentation, with lower pH and buffering capacity, but with lower nutritional value.

  16. Transmission of tomato spotted wilt tospovirus by Thrips tabaci populations originating from leek

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Nagata, T.; Katis, N.I.; Peters, D.

    1999-01-01

    The transmission of tomato spotted wilt tospovirus (TSWV) by Thrips tabaci collected from leek was studied using the petunia local-lesion leaf-disc assay. After an acquisition-access period of 72 h given to newborn larvae up to 8 h old, the efficiency of transmission by adults was determined in

  17. The route of tomato spotted wilt virus inside the thrips body in relation to transmission efficiency

    NARCIS (Netherlands)

    Kritzman, A.; Gera, A.; Raccah, B.; Lent, van J.W.M.; Peters, D.

    2002-01-01

    The route of tomato spotted wilt virus (TSWV) in the body of its vectors, Frankliniella occidentalis and Thrips tabaci (Thysanoptera: Thripidae) was studied during their development. First instar larvae were allowed, immediately upon hatching, to acquire virus from mechanically infected Datura

  18. Occurrence of Tomato spotted wilt virus in Stevia rebaudiana and Solanum tuberosum in Northern Greece

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Peters, D.; Lolas, P.

    2007-01-01

    Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) was first reported in Greece during 1972 (3) and currently is widespread in the central and northern part of the country infecting several cultivated and wild plant species (1,2). In June 2006, virus-like symptoms similar to

  19. Laurel wilt in natural and agricultural ecosystems: Understanding the drivers and scales of complex pathosystems

    Science.gov (United States)

    Randy Ploetz; Paul Kendra; Robin Choudhury; Jeffrey Rollins; Alina Campbell; Karen Garrett; Marc Hughes; Tyler Dreaden

    2017-01-01

    Laurel wilt kills members of the Lauraceae plant family in the southeastern United States. It is caused by Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional fungal symbiont of an invasive Asian ambrosia beetle, Xyleborus glabratus Eichhoff, which was detected in Port Wentworth, Georgia, in 2002. The beetle...

  20. Bioorganic fertilizer enhances soil suppressive capacity against bacterial wilt of tomato.

    Science.gov (United States)

    Liu, Lijuan; Sun, Chengliang; Liu, Shuangri; Chai, Rushan; Huang, Weiqing; Liu, Xingxing; Tang, Caixian; Zhang, Yongsong

    2015-01-01

    Tomato bacterial wilt caused by Ralstonia solanacearum is one of the most destructive soil-borne diseases. Many strategies have been taken to improve soil suppressiveness against this destructive disease, but limited success has been achieved. In this study, a novel bioorganic fertilizer revealed a higher suppressive ability against bacterial wilt compared with several soil management methods in the field over four growing seasons from March 2011 to July 2013. The application of the bioorganic fertilizer significantly (Pfertilizer increased soil pH value, electric conductivity, organic carbon, NH4+-N, NO3--N and available K content, microbial activities and microbial biomass carbon content, which were positively related with soil suppressiveness. Bacterial and actinomycete populations assessed using classical plate counts were highest, whereas R. solanacearum and fungal populations were lowest in soil applied with the bioorganic fertilizer. Microbial community diversity and richness were assessed using denaturing gel gradient electrophoresis profile analysis. The soil treated with the bioorganic fertilizer exhibited higher bacterial community diversity but lower fungal community diversity. Redundancy analysis showed that bacterial community diversity and richness negatively related with bacterial wilt suppressiveness, while fungal community richness positively correlated with R. solanacearum population. We concluded that the alteration of soil physicochemical and biological properties in soil treated with the bioorganic fertilizer induced the soil suppressiveness against tomato bacterial wilt.

  1. Controlling spread of the oak wilt pathogen (Ceratocystis fagacearum) in a Minnesota urban forest park reserve

    Science.gov (United States)

    Jennifer Juzwik; Joseph O' Brien; Charles Evenson; Paul Castillo; Graham. Mahal

    2010-01-01

    Effectiveness of oak wilt control actions taken between 1997 and 1999 were evaluated for an urban forest park reserve in Minnesota, U.S. A high level of success (84% of evaluated disease centers) was achieved in controlling belowground spread of the vascular pathogen for four to six years by mechanically disrupting inter-tree root connections with the blade of a cable...

  2. Recent Trends in Control Methods for Bacterial Wilt Diseases Caused by Ralstonia solanacearum

    Science.gov (United States)

    Yuliar; Nion, Yanetri Asi; Toyota, Koki

    2015-01-01

    Previous studies have described the development of control methods against bacterial wilt diseases caused by Ralstonia solanacearum. This review focused on recent advances in control measures, such as biological, physical, chemical, cultural, and integral measures, as well as biocontrol efficacy and suppression mechanisms. Biological control agents (BCAs) have been dominated by bacteria (90%) and fungi (10%). Avirulent strains of R. solanacearum, Pseudomonas spp., Bacillus spp., and Streptomyces spp. are well-known BCAs. New or uncommon BCAs have also been identified such as Acinetobacter sp., Burkholderia sp., and Paenibacillus sp. Inoculation methods for BCAs affect biocontrol efficacy, such as pouring or drenching soil, dipping of roots, and seed coatings. The amendment of different organic matter, such as plant residue, animal waste, and simple organic compounds, have frequently been reported to suppress bacterial wilt diseases. The combined application of BCAs and their substrates was shown to more effectively suppress bacterial wilt in the tomato. Suppression mechanisms are typically attributed to the antibacterial metabolites produced by BCAs or those present in natural products; however, the number of studies related to host resistance to the pathogen is increasing. Enhanced/modified soil microbial communities are also indirectly involved in disease suppression. New promising types of control measures include biological soil disinfection using substrates that release volatile compounds. This review described recent advances in different control measures. We focused on the importance of integrated pest management (IPM) for bacterial wilt diseases. PMID:25762345

  3. The history and epidemiology of Cape St Paul wilt disease of ...

    African Journals Online (AJOL)

    The history of the spread of the Cape St. Paul Wilt (lethal yellowing) disease of coconut in Ghana is presented. Epidemiological studies showed that the disease starts slowly, then progresses (accelerate) rapidly before levelling off. In a farm, the disease first appears randomly on single trees, foci then develop around these ...

  4. Biological control of fusarium wilt of tomato by antagonist fungi and ...

    African Journals Online (AJOL)

    Biological control of fusarium wilt of tomato by antagonist fungi and cyanobacteria. ... technique showed that Aspergillus niger, Penicillium citrinum, Penicillium sp. and Trichoderma harzianum inhibited the radial colony growth of the test pathogen. ... Similar results were observed in chlorophyll (a+b) content of treated plants.

  5. Assessing the cost of an invasive forest pathogen; A case study with oak wilt

    Science.gov (United States)

    Robert G. Haight; Frances R. Homans; Tetsuya Horie; Shefali V. Mehta; David J. Smith; Robert C. Venette

    2011-01-01

    Economic assessment of damage caused by invasive alien species provides useful information to consider when determining whether management programs should be established, modified, or discontinued. We estimate the baseline economic damage from an invasive alien pathogen, Ceratocystis fagacearum, a fungus that causes oak wilt, which is a significant...

  6. Antagonistic activity of Bacillus subtilis SB1 and its biocontrol effect on tomato bacterial wilt

    Science.gov (United States)

    A potential biocontrol agent of bacterial wilt, Bacillus subtilis SB1, isolated from tomato roots, showed a broad-spectrum of antimicrobial activity in in vitro experiments. It inhibited the growth of many plant pathogens, including Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, Fusarium ox...

  7. evaluation of enset clones against enset bacterial wilt abstract résumé

    African Journals Online (AJOL)

    jen

    clones in fields, but each clone is grown for its specific use. A large number of enset clones collected from the. Sidama, Gurage, Kembata Tembaro and Hadyia zones were assessed for resistance/tolerance to enset bacterial wilt, Xanthomonas campestris pv. musacearum (Xcm) at the Awassa Agricultural Research Center, ...

  8. Role of the envelope glycoproteins in the infection cycle of tomato spotted wilt virus

    NARCIS (Netherlands)

    Kikkert, M.

    1999-01-01

    Tomato spotted wilt virus (TSWV) forms the type member of the genus Tospovirus , which today harbors more than twelve different species. TSWV is able to infect an enormous variety of different plants, to which it often causes devastating effects,

  9. The presence of a virulence locus discriminates Fusarium oxysporum isolates causing tomato wilt from other isolates

    NARCIS (Netherlands)

    van der Does, H.C.; Lievens, B.; Claes, L.; Houterman, P.M.; Cornelissen, B.J.C.; Rep, M.

    2008-01-01

    Fusarium oxysporum is an asexual fungus that inhabits soils throughout the world. As a species, F. oxysporum can infect a very broad range of plants and cause wilt or root rot disease. Single isolates of F. oxysporum, however, usually infect one or a few plant species only. They have therefore been

  10. Ambrosia beetle communities in forest and agriculture ecosystems with laurel wilt disease

    Science.gov (United States)

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of trees in the family Lauraceae. Redbay ambro...

  11. Comparison of ambrosia beetle communities in two hosts with laurel wilt: swampbay vs. avocado

    Science.gov (United States)

    The invasive redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of tre...

  12. Recent advances in the control of oak wilt in the United States

    Science.gov (United States)

    Dan A. Wilson

    2005-01-01

    Oak wilt, caused by Ceratocystis fagacearum (T.W.Bretz) J. Hunt, is probably the most destructive disease of oak trees (Quercus species) in the United States, and is currently causing high morality at epiphytotic proportions in central Texas. The serious potential for damage pro,pted an increase in federal funding within the past...

  13. Response of Verticillium fungicola var. fungicola, Mycogone perniciosa_and Cladobotrym sp. Mushroom Pathogens to Some Essential Oils

    Directory of Open Access Journals (Sweden)

    Brankica Tanović

    2006-01-01

    Full Text Available Antifungal activity of 18 essential oils was evaluated against Verticillium fungicola var. fungicola, Mycogone perniciosa and Cladobotryum sp., the causal agents of button mushroom diseases. Essential oils including: turpentine, basil, lemon, mint, fenchel, rose geranium, anise, cinnamon, scots pine, clove, thyme, juniper, lavender, orange, eucalyptus, rosemary, bergamot orange and tea tree, were screened for their effectiveness against the pathogens in vitro. In order to investigate fungicidal activity, isolates were exposed to the volatile phase of the oils for seven days. Of the 18 essential oils analyzed, cinnamon, clove, thyme, and tea tree showed the highest antifungal activity against all investigated mycopathogens,with Minimum Fungicidal Concentration (MFC being 0.02 μl/ml of air. Turpentine essential oil expressed the lowest antifungal effect to all isolates tested.

  14. Assessing the Cost of an Invasive Forest Pathogen: A Case Study with Oak Wilt

    Science.gov (United States)

    Haight, Robert G.; Homans, Frances R.; Horie, Tetsuya; Mehta, Shefali V.; Smith, David J.; Venette, Robert C.

    2011-03-01

    Economic assessment of damage caused by invasive alien species provides useful information to consider when determining whether management programs should be established, modified, or discontinued. We estimate the baseline economic damage from an invasive alien pathogen, Ceratocystis fagacearum, a fungus that causes oak wilt, which is a significant disease of oaks ( Quercus spp.) in the central United States. We focus on Anoka County, Minnesota, a 1,156 km2 mostly urban county in the Minneapolis-Saint Paul metropolitan region. We develop a landscape-level model of oak wilt spread that accounts for underground and overland pathogen transmission. We predict the economic damage of tree mortality from oak wilt spread in the absence of management during the period 2007-2016. Our metric of economic damage is removal cost, which is one component of the total economic loss from tree mortality. We estimate that Anoka County has 5.92 million oak trees and 885 active oak wilt pockets covering 5.47 km2 in 2007. The likelihood that landowners remove infected oaks varies by land use and ranges from 86% on developed land to 57% on forest land. Over the next decade, depending on the rates of oak wilt pocket establishment and expansion, 76-266 thousand trees will be infected with discounted removal cost of 18-60 million. Although our predictions of removal costs are substantial, they are lower bounds on the total economic loss from tree mortality because we do not estimate economic losses from reduced services and increased hazards. Our predictions suggest that there are significant economic benefits, in terms of damage reduction, from preventing new pocket establishment or slowing the radial growth of existing pockets.

  15. Evaluation of Cabbage- and Broccoli-genetic Resources for Resistance to Clubroot and Fusarium Wilt

    Directory of Open Access Journals (Sweden)

    Ji Hyun Lee

    2014-12-01

    Full Text Available Clubroot and Fusarium wilt of cole crops (Brassica oleracea L. are destructive diseases which for many years has brought a decline in quality and large losses in yields all over the world. The breeding of resistant cultivars is an effective approach to reduce the use of chemical fungicides and minimize crop losses. This study was conducted to evaluate the resistance of 60 cabbage (B. oleracea var. capitata and 6 broccoli (B. oleracea var. italica lines provided by The RDA-Genebank Information Center to clubroot and Fusarium wilt. To investigate resistance to clubroot, seedlings of the genetic resources were inoculated with Plasmodiophora brassicae by drenching the roots with a mixed spore suspension (1 : 1 of two isolates. Of the tested genetic resources, four cabbage lines were moderately resistant and ‘K166220’ represented the highest resistance to P. brassicae. The others were susceptible to clubroot. On the other hand, to select resistant plants to Fusarium wilt, the genetic resources were inoculated with Fusarium oxysporum f. sp. conglutinans by dipping the roots in spore suspension of the fungus. Among them, 17 cabbage and 5 broccoli lines were resistant, 16 cabbage lines were moderately resistant, and the others were susceptible to Fusarium wilt. Especially, three cabbage (‘IT227115’, ‘K161791’, ‘K173350’ and two broccoli (‘IT227100’, ‘IT227099’ lines were highly resistant to the fungus. We suggest that the resistant genetic resources can be used as a basic material for resistant B. oleracea breeding system against clubroot and Fusarium wilt.

  16. Population densities of corn flea beetle (Coleoptera: Chrysomelidae) and incidence of Stewart's wilt in sweet corn.

    Science.gov (United States)

    Cook, K A; Weinzierl, R A; Pataky, J K; Esker, P D; Nutter, F W

    2005-06-01

    To quantify populations of the corn flea beetle, Chaetocnema pulicaria Melsheimer (Coleoptera: Chrysomelidae), and refine estimates of a threshold for its control to prevent Stewart's wilt caused by Erwinia stewartii, sequential plantings of 'Jubilee' sweet corn were made at 2-wk intervals from April or May through August or September 2001 and 2002 at four locations from southern to northern Illinois: Simpson, Brownstown, Champaign, and Mendota. Densities of C. pulicaria and incidence of Stewart's wilt were monitored weekly. At Mendota, where C. pulicaria populations were decimated by cold temperatures during winter 2000-2001, densities reached 33.3 beetles per 15-cm yellow sticky trap per day by September 2002, after a mild 2001-2002 winter. Maximum incidence of Stewart's wilt in single plots at Simpson, Brownstown, Champaign, and Mendota was 22, 36, 39, and 2%, respectively, in 2001, and 33, 47, 99, and 87%, respectively, in 2002. In 24 plots where beetle densities were < or =2 per trap per day, Stewart's wilt incidence was <5% in 20 plots. We propose that two corn flea beetles per trap per day be used as a threshold for insecticide application to seedlings to control C. pulicaria and minimize subsequent incidence of Stewart's wilt in processing sweet corn. Enzyme-linked immunosorbent assays indicated that E. stewartii incidence in C. pulicaria peaked at 67, 62, and 54%, respectively, at Simpson, Brownstown, and Champaign, in 2001, and at 71, 76, and 60%, respectively, in 2002. Further studies might allow the use of areawide or field-specific estimates of E. stewartii incidence in corn flea beetles for adjusting management decisions.

  17. Assessing the cost of an invasive forest pathogen: a case study with oak wilt.

    Science.gov (United States)

    Haight, Robert G; Homans, Frances R; Horie, Tetsuya; Mehta, Shefali V; Smith, David J; Venette, Robert C

    2011-03-01

    Economic assessment of damage caused by invasive alien species provides useful information to consider when determining whether management programs should be established, modified, or discontinued. We estimate the baseline economic damage from an invasive alien pathogen, Ceratocystis fagacearum, a fungus that causes oak wilt, which is a significant disease of oaks (Quercus spp.) in the central United States. We focus on Anoka County, Minnesota, a 1,156 km(2) mostly urban county in the Minneapolis-Saint Paul metropolitan region. We develop a landscape-level model of oak wilt spread that accounts for underground and overland pathogen transmission. We predict the economic damage of tree mortality from oak wilt spread in the absence of management during the period 2007-2016. Our metric of economic damage is removal cost, which is one component of the total economic loss from tree mortality. We estimate that Anoka County has 5.92 million oak trees and 885 active oak wilt pockets covering 5.47 km(2) in 2007. The likelihood that landowners remove infected oaks varies by land use and ranges from 86% on developed land to 57% on forest land. Over the next decade, depending on the rates of oak wilt pocket establishment and expansion, 76-266 thousand trees will be infected with discounted removal cost of $18-60 million. Although our predictions of removal costs are substantial, they are lower bounds on the total economic loss from tree mortality because we do not estimate economic losses from reduced services and increased hazards. Our predictions suggest that there are significant economic benefits, in terms of damage reduction, from preventing new pocket establishment or slowing the radial growth of existing pockets.

  18. The significance of ecology in the development of Verticillium chlamydosporium as a biological control agent against root-knot nematodes (Meloidogyne spp.)

    OpenAIRE

    Leij, de, F.A.A.M.

    1992-01-01

    A thorough understanding of the interactions which occur between nematode parasites and nematode pests and the influence of biotic and abiotic factors on these interactions, is essential in the development of biological control agents for nematodes. The aim of this study was to develop a particular isolate of the nematophagous fungus Verticillium chlamydosporium as a biological control agent for root-knot nematodes. The work has gained insight into some of the ke...

  19. Genome sequence of Kosakonia radicincitans UMEnt01/12, a bacterium associated with bacterial wilt diseased banana plant.

    Science.gov (United States)

    Suhaimi, Nurul Shamsinah Mohd; Yap, Kien-Pong; Ajam, Noni; Thong, Kwai-Lin

    2014-09-01

    Kosakonia radicincitans (formerly known as Enterobacter radicincitans), an endophytic bacterium was isolated from the symptomatic tissues of bacterial wilt diseased banana (Musa spp.) plant in Malaysia. The total genome size of K. radicincitans UMEnt01/12 is 5 783 769 bp with 5463 coding sequences (CDS), 75 tRNAs, and 9 rRNAs. The annotated draft genome of the K. radicincitans UMEnt01/12 strain might shed light on its role as a bacterial wilt-associated bacterium.

  20. Identification of major QTLs underlying tomato spotted wilt virus resistance in peanut cultivar Florida-EP(TM) '113'.

    Science.gov (United States)

    Tseng, Yu-Chien; Tillman, Barry L; Peng, Ze; Wang, Jianping

    2016-09-06

    Spotted wilt caused by tomato spotted wilt virus (TSWV) is one of the major peanut (Arachis hypogaea L.) diseases in the southeastern United States. Occurrence, severity, and symptoms of spotted wilt disease are highly variable from season to season, making it difficult to efficiently evaluate breeding populations for resistance. Molecular markers linked to spotted wilt resistance could overcome this problem and allow selection of resistant lines regardless of environmental conditions. Florida-EP(TM) '113' is a spotted wilt resistant cultivar with a significantly lower infection frequency. However, the genetic basis is still unknown. The objective of this study is to map the major quantitative trait loci (QTLs) linked to spotted wilt resistance in Florida-EP(TM) '113'. Among 2,431 SSR markers located across the whole peanut genome screened between the two parental lines, 329 were polymorphic. Those polymorphic markers were used to further genotype a representative set of individuals in a segregating population. Only polymorphic markers on chromosome A01 showed co-segregation between genotype and phenotype. Genotyping by sequencing (GBS) of the representative set of individuals in the segregating population also depicted a strong association between several SNPs on chromosome A01 and the trait, indicating a major QTL on chromosome A01. Therefore marker density was enriched on the A01 chromosome. A linkage map with 23 makers on chromosome A01 was constructed, showing collinearity with the physical map. Combined with phenotypic data, a major QTL flanked by marker AHGS4584 and GM672 was identified on chromosome A01, with up to 22.7 % PVE and 9.0 LOD value. A major QTL controlling the spotted wilt resistance in Florida-EP(TM) '113' was identified. The resistance is most likely contributed by PI 576638, a hirsuta botanical-type line, introduced from Mexico with spotted wilt resistance. The flanking markers of this QTL can be used for further fine mapping and marker

  1. Success evaluation of the biological control of Fusarium wilts of cucumber, banana, and tomato since 2000 and future research strategies.

    Science.gov (United States)

    Raza, Waseem; Ling, Ning; Zhang, Ruifu; Huang, Qiwei; Xu, Yangchun; Shen, Qirong

    2017-03-01

    The Fusarium wilt caused by Fusarium oxysporum strains is the most devastating disease of cucumber, banana, and tomato. The biological control of this disease has become an attractive alternative to the chemical fungicides and other conventional control methods. In this review, the research trends and biological control efficiencies (BCE) of different microbial strains since 2000 are reviewed in detail, considering types of microbial genera, inoculum application methods, plant growth medium and conditions, inoculum application with amendments, and co-inoculation of different microbial strains and how those affect the BCE of Fusarium wilt. The data evaluation showed that the BCE of biocontrol agents was higher against the Fusarium wilt of cucumber compared to the Fusarium wilts of banana and tomato. Several biocontrol agents mainly Bacillus, Trichoderma, Pseudomonas, nonpathogenic Fusarium, and Penicillium strains were evaluated to control Fusarium wilt, but still this lethal disease could not be controlled completely. We have discussed different reasons of inconsistent results and recommendations for the betterment of BCE in the future. This review provides knowledge of the biotechnology of biological control of Fusarium wilt of cucumber, banana, and tomato in a nut shell that will provide researchers a beginning line to start and to organize and plan research for the future studies.

  2. Primeiro relato do Tomato spotted wilt virus (TSWV) em Campanula medium L. no Brasil First report of Tomato spotted wilt virus (TSWV) infecting Campanula medium in Brazil

    OpenAIRE

    Ricardo Gioria; Kátia Regiane Brunelli; Romulo Fujito Kobori; Márcia Maria Rabelo Guimarães Kobori; Jorge Alberto Marques Rezende; Elliot Watanabe Kitajima

    2010-01-01

    Plantas de campânula (Campanula medium) exibindo mosaico e necrose foliar e anéis em flores foram coletadas em uma estufa comercial de flores na região de Atibaia, SP. Suspeitando de possível etiologia viral, amostras de tecido lesionado foram analisadas por ensaios de transmissão mecânica, microscopia eletrônica e sorologia. Todos os resultados apontaram para a presença do Tomato spotted wilt virus (TSWV) como o responsável pelos sintomas. Esse é o primeiro relato deste patógeno em campânula...

  3. Interaction of Tomato Spotted Wilt Tospovirus (TSWV) Glycoproteins with a Thrips Midgut Protein, a Potential Cellular Receptor for TSWV.

    Science.gov (United States)

    Bandla, M D; Campbell, L R; Ullman, D E; Sherwood, J L

    1998-02-01

    ABSTRACT Interactions between viral and cellular membrane fusion proteins mediate virus penetration of cells for many arthropod-borne viruses. Electron microscope observations and circumstantial evidence indicate insect acquisition of tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) is receptor mediated, and TSWV membrane glycoproteins (GP1 and GP2) serve as virus attachment proteins. The tospoviruses are plant-infecting members of the family Bunyaviridae and are transmitted by several thrips species, including Frankliniella occidentalis. Gel overlay assays and immunolabeling were used to investigate the putative role of TSWV GPs as viral attachment proteins and deter mine whether a corresponding cellular receptor may be present in F. occidentalis. A single band in the 50-kDa region was detected with murine monoclonal antibodies (MAbs) to the TSWV-GPs when isolated TSWV or TSWV-GPs were used to overlay separated thrips proteins. This band was not detected when blots were probed with antibody to the non-structural protein encoded by the small RNA of TSWV or the TSWV nucleocapsid protein, nor were proteins from nonvector insects labeled. Anti-idiotype antibodies prepared to murine MAbs against GP1 or GP2 specifically labeled a single band at 50 kDa in Western blots and the plasmalemma of larval thrips midguts. These results support the putative role of the TSWV GPs as viral attachment proteins and identified potential cellular receptor(s) in thrips.

  4. Isolation and characterization of a chitinase gene from entomopathogenic fungus Verticillium lecanii Isolamento e caracterização de um gene de quitinase do fungo entomopatogênico Verticillium lecanii

    Directory of Open Access Journals (Sweden)

    Yanping Zhu

    2008-06-01

    Full Text Available Entomopathogenic fungus Verticillium lecanii is a promising whitefly and aphid control agent. Chitinases secreted by this insect pathogen have considerable importance in the biological control of some insect pests. An endochitinase gene Vlchit1 from the fungus was cloned and overexpressed in Escherichia coli. The Vlchit1 gene not only contains an open reading frame (ORF which encodes a protein of 423 amino acids (aa, but also is interrupted by three short introns. A homology modelling of Vlchit1 protein showed that the chitinase Vlchit1 has a (α/β8 TIM barrel structure. Overexpression test and Enzymatic activity assay indicated that the Vlchit1 is a functional enzyme that can hydrolyze the chitin substrate, so the Vlchit1 gene can service as a useful gene source for genetic manipulation leading to strain improvement of entomopathogenic fungi or constructing new transgenic plants with resistance to various fungal and insects pests.O fungo entomopatogênico Verticillium lecanii é um agente promissor no controle da mosca-branca e do pulgão. As quitinases secretadas por esse patógeno de insetos têm uma grande importância no controle biológico de doenças causadas por insetos. Um gene de endoquitinase Vlchit1 desse fungo foi clonado e expresso em Escherichia coli. O gene Vlchit contém não apenas um ORF que codifica uma proteína de 423 aminoácidos, mas também é interrompido por três pequenos introns. A modelagem de homologia da proteína Vlchit1indicou que a quitinase Vlchit1 tem uma estrutura (α/β 8 TIM barrel. Testes de expressão e de atividade enzimática indicaram que Vlchit1 é uma enzima funcional que hidroliza quitina, portanto o gene Vlchit pode ser um gene útil para manipulação genética para melhoramento de cepas de fungos entomopatogênicos ou para a construção de novas plantas transgênicas com resistência a várias doenças causadas por fungos e insetos.

  5. Thyme essential oil as a defense inducer of tomato against gray mold and Fusarium wilt.

    Science.gov (United States)

    Ben-Jabeur, Maissa; Ghabri, Emna; Myriam, Machraoui; Hamada, Walid

    2015-09-01

    The potential of thyme essential oil in controlling gray mold and Fusarium wilt and inducing systemic acquired resistance in tomato seedlings and tomato grown in hydroponic system was evaluated. Thyme oil highly reduced 64% of Botrytis cinerea colonization on pretreated detached leaves compared to untreated control. Also, it played a significant decrease in Fusarium wilt severity especially at7 days post treatment when it was reduced to 30.76%. To explore the plant pathways triggered in response to thyme oil, phenolic compounds accumulation and peroxidase activity was investigated. Plant response was observed either after foliar spray or root feeding in hydroponics which was mostly attributed to peroxidases accumulation rather than phenolic compounds accumulation, and thyme oil seems to be more effective when applied to the roots. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Risk analysis and guidelines for harvest activities in wisconsin oak timberlands to minimize oak wilt threat

    Science.gov (United States)

    Jennifer Juzwik; Jane Cummings-Carlson; Kyoko Scanlon

    2010-01-01

    Oaks (Quercus spp.) are an important species group in the forests of Wisconsin. The State’s timberland typed as oak-hickory forest was estimated at 2.9 million acres in 1996. Growing stock volume for red oak was estimated at 2.4 billion cubic feet, whereas select white oak volume was estimated to be 927 million cubic feet. Oak wilt, the oak disease...

  7. Effects of Biochar Amendment on Tomato Bacterial Wilt Resistance and Soil Microbial Amount and Activity

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Bacterial wilt is a serious soilborne disease of Solanaceae crops which is caused by Ralstonia solanacearum. The important role of biochar in enhancing disease resistance in plants has been verified; however, the underlying mechanism remains not fully understood. In this study, two different biochars, made from peanut shell (BC1 and wheat straw (BC2, were added to Ralstonia solanacearum-infected soil to explore the interrelation among biochar, tomato bacterial wilt, and soil microbial properties. The results showed that both BC1 and BC2 treatments significantly reduced the disease index of bacterial wilt by 28.6% and 65.7%, respectively. The populations of R. solanacearum in soil were also significantly decreased by biochar application. Ralstonia solanacearum infection significantly reduced the densities of soil bacteria and actinomycetes and increased the ratio of soil fungi/bacteria in the soil. By contrast, BC1 and BC2 addition to pathogen-infected soil significantly increased the densities of soil bacteria and actinomycetes but decreased the density of fungi and the ratios of soil fungi/bacteria and fungi/actinomycetes. Biochar treatments also increased soil neutral phosphatase and urease activity. Furthermore, higher metabolic capabilities of microorganisms by biochar application were found at 96 and 144 h in Biolog EcoPlates. These results suggest that both peanut and wheat biochar amendments were effective in inhibiting tomato bacterial wilt caused by R. solanacearum. The results suggest a relationship between the disease resistance of the plants and the changes in soil microbial population densities and activity.

  8. Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes

    OpenAIRE

    Trojak-Goluch, Anna; Laskowska, Dorota; Agacka, Monika; Czarnecka, Diana; Kawka, Magdalena; Czubacka, Anna

    2011-01-01

    Black root rot (BRR) caused by Thielaviopsis basicola as well as Tomato spotted wilt virus (TSWV) are the most serious problems in tobacco growing regions. We crossed the breeding line WGL 3 carrying BRR resistance derived from N.glauca with the line PW-834 the resistance of which to TSWV was transferred from cultivar Polalta. Anthers obtained from F1 hybrid plants were cultured to induce haploids combining resistance to Th. basicola and TSWV. Flow cytometry analysis revealed 242 haploids and...

  9. Pattern of the Occurrence of Tomato spotted wilt virus in Jeonnam Province

    OpenAIRE

    Sug-Ju Ko; Beom-Ryong Kang; Duck-Soo Choi; Do-Ik Kim; Gwan-Seok Lee; Chang-Seok Kim; Hong-Soo Choi

    2013-01-01

    Tomato spotted wilt virus (TSWV) was occurred at 8 areas including Naju, Suncheon, Younggwang, Youngam, and Shinan in Jeonnam province and the crops of Younggwang were severely damaged by TSWV. The hot pepper (Capsicum annuum), bell pepper (Capsicum annuum v ar. angulosum) and tomato (Solanum lycopersicon) in greenhouse and hot pepper in open field were infected by TSWV. Especially, hot pepper was severely damaged by TSWV infection. The survey data indicated that 1.1−30% in the nu...

  10. Effects of Some Additives, Harvest Stage and Wilting on Quality Characteristics of Alfalfa Silage

    OpenAIRE

    DUMLU GÜL, Zeynep; Tan, Mustafa; FAYETÖRBAY KAYNAR, Dilara; KHARAZMİ, Kambiz

    2016-01-01

    ABSTRACT: Although alfalfa is a good forage plant, it is one of the difficult to ensiled crops. The high protein content, low water soluble carbohydrate and dry matter content of alfalfa prevents healthy fermentation. Therefore, this study focused on the use of additives, arrangement of cutting time and wilting after cutting of alfalfa to make successful silage. The research was carried out at Ataturk University, Faculty of Agriculture in Erzurum, Turkey. It was arranged in a completely rando...

  11. Expression and Characterization of a Soluble Form of Tomato Spotted Wilt Virus Glycoprotein GN

    OpenAIRE

    Whitfield, Anna E.; Ullman, Diane E.; German, Thomas L

    2004-01-01

    Tomato spotted wilt virus (TSWV), a member of the Tospovirus genus within the Bunyaviridae, is an economically important plant pathogen with a worldwide distribution. TSWV is transmitted to plants via thrips (Thysanoptera: Thripidae), which transmit the virus in a persistent propagative manner. The envelope glycoproteins, GN and GC, are critical for the infection of thrips, but they are not required for the initial infection of plants. Thus, it is assumed that the envelope glycoproteins play ...

  12. Native cell-death genes as candidates for developing wilt resistance in transgenic banana plants

    OpenAIRE

    Ghag, Siddhesh B.; Shekhawat, Upendra K. Singh; Ganapathi, Thumballi R.

    2014-01-01

    In order to feed an ever-increasing world population, there is an urgent need to improve the production of staple food and fruit crops. The productivity of important food and fruit crops is constrained by numerous biotic and abiotic factors. The cultivation of banana, which is an important fruit crop, is severely threatened by Fusarium wilt disease caused by infestation by an ascomycetes fungus Fusarium oxysporum f. sp. cubense (Foc). Since there are no established edible cultivars of banana ...

  13. Herbicide-induced Resistance to Fusarium Wilt in Cotton and Gossypol Production of Host Cells

    OpenAIRE

    CANIHOŞ, Yeter

    2014-01-01

    Pretreating cotton seeds with some herbicidies used in cotton-growing areas of the Çukurova region markedly increased cotton resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum. Haloxyfob and linuron reduced the mycelial growth of the pathogen in both solid and liquid cultures. However, prometryn was more effective in plant development than linuron and haloxyfob. Synthesis of Phytoalexin gossypol was significantly produced in inoculated cotton plants compared with u...

  14. Survival of oak root systems following frill girdle herbicide treatment for oak wilt control

    Science.gov (United States)

    Johann N. Bruhn; James J., Jr. Wetteroff; Linda Haugen

    2003-01-01

    Mechanical separation of root systems is widely used to prevent tree-to-tree vascular spread of oak wilt disease. A safe effective herbicide treatment would be valuable for this purpose in hilly, rocky, or urban settings. Three treatments were frill-girdle applied: 1) water, 2) undilutetd Garlon 3A (trichlopyr), or 3) half-strength aqueous Garlon 3A plus 24 ml per L...

  15. EVALUATION OF LENTIL GERMPLASM FOR DISEASE RESISTANCE TO FUSARIUM WILT (FUSARIUM OXYSPORUM F.SP. LENTIS)

    OpenAIRE

    Tzvetelina Stoilova; Peter Chavdarov

    2006-01-01

    Lentil (Lens culinaris Medic.) is one of the oldest known protein-rich food legumes. Lentil is the second pulse crop after dry bean in Bulgaria. Diseases such as Ascochyta blight and Lentil wilt play a major role in reducing lentil yield. Thirty two lentil genotypes with different geographical origin were screened for reaction to Fusarium oxysporum f.sp. lentis during 2003-2004 from the Institute for Plant Genetic Resourses, Sadovo under greenhouse conditions. Three of the studied accessions ...

  16. The Use of Antioxidants to Control Root Rot and Wilt Diseases of Pepper

    Directory of Open Access Journals (Sweden)

    Montaser Fawzy ABDEL-MONAIM

    2010-06-01

    Full Text Available Ten isolates of Fusarium spp were isolated from pepper plants collected from different locations in New Valley Governorate, Egypt. Fusarium solani isolate FP2 and F. oxysporum isolate FP4 were highly pathogenic isolates but the other isolates moderate or less pathogenic to pepper plants (cv. Anaheim-M. The four antioxidant compounds (coumaric acid, citric acid, propylgalate and salicylic acid each at 100 and 200 ppm were evaluated for their in vitro and in vivo agonist to Fusarium pathogenic isolates caused root rot and wilt diseases in pepper plants. All tested antioxidant compounds reduced damping-off, root rot/wilt and area under root rot/wilt progress curve when used as seed soaking, seedling soaking, and soil drench especially at 200 ppm under greenhouse and field conditions compared with untreated plants. All chemicals increased fresh and dry weight of seedling grown in soil drenching or seed treatment with any antioxidants. At the same time, all tested chemicals significantly increase plant growth parameters i.e plant length, plant branching, and total yield per plant in case of seedling soaking or soil drench. In general, propylgalate at 200 ppm was more efficient in reducing infection with damping-off, root rot and wilt diseases as well as increasing the seedling fresh weight, dry weight, plant length, plant branching, number of pod plant-1 and pod yield plant-1. On the other hand, all tested antioxidants had less or no effect on mycelial dry weight and mycelial leaner growth. On the contrary, all chemicals much reduced spore formation in both Fusarium species at 100 or 200 ppm and the inhibitory effect of antioxidants increased with increasing their concentrations.

  17. Trichoderma harzianum in combination with sheep manure amendment enhances soil suppressiveness of Fusarium wilt of tomato

    Directory of Open Access Journals (Sweden)

    R. M. Barakat

    2010-01-01

    Full Text Available The effect that the biocontrol agent Trichoderma harzianum (isolate Jn14 in combination with an amendment of sheep manure has on the soil suppressiveness of Fusarium wilt of tomato was investigated over a 28-month period. A combination of T. harzianum and organic amendment at concentrations (w:w of 6 and 10% reduced tomato wilt by 21–36 % and 29–36% respectively, after 0–28 months of soil incubation. When the amendment was added at concentration of 2%, the wilt was suppressed only after 18–28 months. A combination of T. harzianum and the amendment at 6% also increased tomato plant fresh weights by 52% after 28 months, and the 10% amendment increased fresh weights by 56, 40, and 63%, after 18, 24, and 28 months respectively, compared to the experimental controls. Organic amendment at the higher concentrations further stimulated T. harzianum populations, enhanced microbial activity against Fusarium oxysporum in the soil and reduced pathogen populations. Without T. harzianum, the organic amendment at a concentration of 10% reduced disease by only 22, 24, and 23% and only after 18, 24 and 28 months of soil incubation respectively, compared with the controls. However, tomato wilt was not reduced at a 2% manure concentration in less than 12 months of incubation. Organic amendment alone at 6 and 10% reduced the pathogen population by 25% and 37% respectively after 28 months of soil incubation compared with the control. T. harzianum produced fungitoxic metabolites that reduced mycelial growth of Fusarium by 37% and conidium germination by 55% when the pathogen was grown on potato dextrose agar amended with a T. harzianum culture filtrate.

  18. Biocontrol of Fusarium wilt disease in tomato by Paenibacillus ehimensis KWN38.

    Science.gov (United States)

    Naing, Kyaw Wai; Nguyen, Xuan Hoa; Anees, Muhammad; Lee, Yong Seong; Kim, Yong Cheol; Kim, Sang Jun; Kim, Myung Hee; Kim, Yong Hwan; Kim, Kil Yong

    2015-01-01

    This study was conducted to investigate biocontrol potential of Paenibacillus ehimensis KWN38 against Fusarium oxysporum f.sp. lycopersici causing Fusarium wilt disease in tomato. Our result showed that P. ehimensis KWN38 produced extracellular organic compounds and crude enzyme to inhibit F. oxysporum f.sp. lycopersici conidial germination in in vitro assays. Tomato seedlings were treated with water (W), grass medium (G), G with P. ehimensis KWN38 inoculation (GP) and G along with synthetic fungicide (GSf). Disease symptoms were was first observed in G and W at 12 days after infection (DAI) while symptoms were noticeable in the GP and GSf treatments at 20 and 24 DAI, respectively. Tomato plants treated with P. ehimensis KWN38 or fungicide significantly reduced Fusarium wilt disease incidence and severity as compared to control tomato plants treated with water and grass medium. The similar results were also found in the root mortality of tomato plants. At 25 DAI, most plants in control treatments (W and G) wilted and the brown vascular systems of infected plants was clearly differentiable from normal green vascular system of healthy plants from GP and GSf. Plants in the GP showed higher fresh and dry weights of both root and shoots than those in W and G treatments. Leaf peroxidase and polyphenol oxidase activities of tomato plants in G and W were higher than those in GP and GSf. Root enzyme activities showed a similar pattern but the values were higher than leaf enzyme. The results clearly demonstrated that P. ehimensis KWN38 may be considered as biocontrol agent of Fusarium wilt disease in tomato.

  19. Laurel Wilt in Natural and Agricultural Ecosystems: Understanding the Drivers and Scales of Complex Pathosystems

    Directory of Open Access Journals (Sweden)

    Randy C. Ploetz

    2017-02-01

    Full Text Available Laurel wilt kills members of the Lauraceae plant family in the southeastern United States. It is caused by Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional fungal symbiont of an invasive Asian ambrosia beetle, Xyleborus glabratus Eichhoff, which was detected in Port Wentworth, Georgia, in 2002. The beetle is the primary vector of R. lauricola in forests along the southeastern coastal plain of the United States, but other ambrosia beetle species that obtained the pathogen after the initial introduction may play a role in the avocado (Persea americana Miller pathosystem. Susceptible taxa are naïve (new-encounter hosts that originated outside Asia. In the southeastern United States, over 300 million trees of redbay (P. borbonia (L. Spreng. have been lost, and other North American endemics, non-Asian ornamentals and avocado—an important crop that originated in MesoAmerica—are also affected. However, there are no reports of laurel wilt on the significant number of lauraceous endemics that occur in the Asian homeland of R. lauricola and X. glabratus; coevolved resistance to the disease in the region has been hypothesized. The rapid spread of laurel wilt in the United States is due to an efficient vector, X. glabratus, and the movement of wood infested with the insect and pathogen. These factors, the absence of fully resistant genotypes, and the paucity of effective control measures severely constrain the disease’s management in forest ecosystems and avocado production areas.

  20. Water Extract from Spent Mushroom Substrate of Hericium erinaceus Suppresses Bacterial Wilt Disease of Tomato.

    Science.gov (United States)

    Kwak, A Min; Min, Kyeong Jin; Lee, Sang Yeop; Kang, Hee Wan

    2015-09-01

    Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding β-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.

  1. Host-Induced Silencing of Pathogenicity Genes Enhances Resistance to Fusarium oxysporum Wilt in Tomato.

    Science.gov (United States)

    Bharti, Poonam; Jyoti, Poonam; Kapoor, Priya; Sharma, Vandana; Shanmugam, V; Yadav, Sudesh Kumar

    2017-08-01

    This study presents a novel approach of controlling vascular wilt in tomato by RNAi expression directed to pathogenicity genes of Fusarium oxysporum f. sp. lycopersici. Vascular wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici leads to qualitative and quantitative loss of the crop. Limitation in the existing control measures necessitates the development of alternative strategies to increase resistance in the plants against pathogens. Recent findings paved way to RNAi, as a promising method for silencing of pathogenicity genes in fungus and provided effective resistance against fungal pathogens. Here, two important pathogenicity genes FOW2, a Zn(II)2Cys6 family putative transcription regulator, and chsV, a putative myosin motor and a chitin synthase domain, were used for host-induced gene silencing through hairpinRNA cassettes of these genes against Fusarium oxysporum f. sp. lycopersici. HairpinRNAs were assembled in appropriate binary vectors and transformed into tomato plant targeting FOW2 and chsV genes, for two highly pathogenic strains of Fusarium oxysporum viz. TOFOL-IHBT and TOFOL-IVRI. Transgenic tomatoes were analyzed for possible attainment of resistance in transgenic lines against fungal infection. Eight transgenic lines expressing hairpinRNA cassettes showed trivial disease symptoms after 6-8 weeks of infection. Hence, the host-induced posttranscriptional gene silencing of pathogenicity genes in transgenic tomato plants has enhanced their resistance to vascular wilt disease caused by Fusarium oxysporum.

  2. Effects of soil application of fly ash on the fusarial wilt on tomato cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M.R.; Singh, W.N. [Aligarh Muslim University, Aligarh (India). Dept. of Plant Protection, Rafi Ahmad Kidwai Institute of Agricultural Science

    2001-07-01

    A study was carried out in microplots to evaluate the effect of fly ash on the plant growth and yield of tomato cultivars, Pusa Ruby, Pusa Early Dwarf and New Uday, and on wilt disease caused by Fusarium oxysporum f. sp. lycopersici. Fly ash was applied to soil by broadcast or in rows at the rate of 1, 2, 3 and 4 kg ash m{sup -2} in place of inorganic fertilizers. In control plots, NPK (about 40 : 20 : 20 kg acre{sup -1}) and compost were added in place of fly ash. Ash application greatly increased the soil contents of P, K, B, Ca, Mg, Mn, Zn, carbonates, bicarbonates and sulphates. Plants grown in the ash-treated plots, especially at 3 or 4 kg dose, showed luxuriant growth and greener foliage, and plant growth and yield of the three cultivars were significantly increased in comparison with the plants grown in plots without fly ash. The wilt fungus, F. oxysporum f. sp. lycopersiciat the inoculum level of 2 g plant{sup -1} caused significant suppression of growth and yield in all three cultivars. Application of fly ash, however, checked the suppressive effect of the fungus, leading to a significant increase in the considered variables compared with the inoculated control. Soil population of the fungus gradually decreased with an increase in ash dose. Row application was found to be relatively more effective in enhancing the yield of tomato cultivars and suppressing the wilt disease.

  3. Management of spotted wilt vectored by Frankliniella fusca (Thysanoptera: Thripidae) in Virginia market-type peanut.

    Science.gov (United States)

    Hurt, C A; Brandenburg, R L; Jordan, D L; Kennedy, G G; Bailey, J E

    2005-10-01

    Field tests were conducted during 2001 and 2002 in northeastern North Carolina to evaluate the impact of cultural practices and in-furrow insecticides on the incidence of Tomato spotted wilt virus (genus Tospovirus, family Bunyaviridae, TSWV), which is transmitted to peanut, Arachis hypogaea L., primarily by tobacco thrips, Frankliniella fusca Hinds (Thysanoptera: Thripidae). Treatments included in row plant populations of 7, 13, and 17 plants per meter; the virginia market-type 'NC V-11' and 'Perry'; planting dates of early and late May; and phorate and aldicarb insecticide applied in-furrow. The incidence of plants expressing visual symptoms of spotted wilt was recorded from mid-June through mid-September. Treatment factors that reduced the incidence of symptoms of plants expressing spotted wilt symptoms included establishing higher plant densities, delaying planting from early May until late May, and applying the in-furrow insecticide phorate. Peanut cultivar did not have a consistent, significant effect on the incidence of symptomatic plants in this experiment.

  4. Fusarium oxysporum: exploring the molecular arsenal of a vascular wilt fungus.

    Science.gov (United States)

    Pietro, Antonio Di; Madrid, Marta P; Caracuel, Zaira; Delgado-Jarana, Jesús; Roncero, M Isabel G

    2003-09-01

    SUMMARY Taxonomy: Vascular wilt fungus; Ascomycete although sexual stage is yet to be found. The most closely related teleomorphic group, Gibberella, is classified within the Pyrenomycetes. Very broad at the species level. More than 120 different formae speciales have been identified based on specificity to host species belonging to a wide range of plant families. Disease symptoms: Initial symptoms of vascular wilt include vein clearing and leaf epinasty, followed by stunting, yellowing of the lower leafs, progressive wilting of leaves and stem, defoliation and finally death of the plant. In cross-sections of the stem, a brown ring is evident in the area of the vascular bundles. Some formae speciales are not primarily vascular pathogens but cause foot- and rootrot or bulbrot. Economic importance: Causes severe losses on most vegetables and flowers, several field crops such as cotton and tobacco, plantation crops such as banana, plantain, coffee and sugarcane, and a few shade trees. Use of resistant varieties is the only practical measure for controlling the disease in the field. Under greenhouse conditions, soil sterilization can be performed. Alternative control methods with potential for the future include soil solarization and biological control with antagonistic bacteria or fungi. http://www.fgsc.net/fus.htm, http://www-genome.wi.mit.edu/annotation/fungi/fusarium/, http://www.cbs.knaw.nl/fusarium/database.html.

  5. Evaluating the Correlations and Sequence of Plant Drought Responses: Coordination Among Stomatal, Hydraulic, and Wilting Traits

    Science.gov (United States)

    Bartlett, M. K.; Klein, T.; Jansen, S.; Choat, B.; Sack, L.

    2016-12-01

    Climate change is expected to exacerbate drought for many plants, making drought tolerance a key driver of species and ecosystem responses. Plant responses to drought are determined by multiple traits, but the relationships among these traits, either within individual plants or across species, have not been evaluated for general patterns across plant diversity. We synthesized the published data for the water potential thresholds that induce stomatal closure, wilting, plant mortality, and declines in hydraulic conductivity in the leaves, stems, and roots for 262 woody angiosperm and 48 gymnosperm species. We evaluated the correlations among these traits across species, and the general sequence of water potential thresholds for these traits within individual plants. The trait correlations across species provide a framework for predicting plant responses to a wide range of water stress from one or two sampled traits, increasing the ability to rapidly characterize drought tolerance across diverse species. Analyzing these correlations also identified functional coordination among the leaf and stem hydraulic traits and the wilting point, or turgor loss point, beyond those expected from shared ancestry or independent associations with water stress alone. Further, on average, woody dicot species generally exhibited a sequence of drought tolerance traits that is expected to limit severe tissue damage during drought, such as wilting and substantial stem embolism. This synthesis of the relationships among the drought tolerance traits provides crucial, empirically-supported insight into representing variation in multiple traits in models of plant and ecosystem responses to drought.

  6. The effect of lactic acid bacterial starter culture and chemical additives on wilted rice straw silage.

    Science.gov (United States)

    Wang, Yan-Su; Shi, Wei; Huang, Lin-Ting; Ding, Cheng-Long; Dai, Chuan-Chao

    2016-04-01

    Lactic acid bacteria (LAB) are suitable for rice straw silage fermentation, but have been studied rarely, and rice straw as raw material for ensiling is difficult because of its disadvantages, such as low nutrition for microbial activities and low abundances of natural populations of LAB. So we investigated the effect of application of LAB and chemical additives on the fermentation quality and microbial community of wilted rice straw silage. Treatment with chemical additives increased the concentrations of crude protein (CP), water soluble carbohydrate (WSC), acetic acid and lactic acid, reduced the concentrations of acid detergent fiber (ADF) and neutral detergent fiber (NDF), but did not effectively inhibit the growth of spoilage organisms. Inoculation with LABs did not improve the nutritional value of the silage because of poor growth of LABs in wilted rice straw. Inoculation with LAB and addition of chemical materials improved the quality of silage similar to the effects of addition of chemical materials alone. Growth of aerobic and facultatively anaerobic bacteria was inhibited by this mixed treatment and the LAB gradually dominated the microbial community. In summary, the fermentation quality of wilted rice straw silage had improved by addition of LAB and chemical materials. © 2015 Japanese Society of Animal Science.

  7. Identification and biocontrol efficacy of Streptomyces miharaensis producing filipin III against Fusarium wilt.

    Science.gov (United States)

    Kim, Jeong Do; Han, Jae Woo; Hwang, In Cheon; Lee, Dongho; Kim, Beom Seok

    2012-04-01

    A number of bacterial strains were isolated from the internal tissue of Trapa japonica. Of these, strain KPE62302H, which had a 16S rDNA sequence identical to that of Streptomyces miharaensis showed antifungal activity against several plant pathogens. Treatment of seeds with strain KPE62302H induced a significant reduction in the incidence of Fusarium wilt in tomato plants compared with untreated controls. An antifungal substance (FP-1) was purified from the culture extract of strain KPE62302H using C18 flash and Sephadex LH-20 column chromatography and reverse phase HPLC. Extensive spectrometric analysis using MS and NMR identified this as filipin III. FP-1 inhibited the mycelial growth of plant pathogenic fungi such as Alternaria mali, Aspergillus niger, Colletotrichum gloeosporioides, C. orbiculare, Cylindrocarpon destructans, Diaporthe citiri, Fusarium oxysporum at 1-10 μg ml(-1) and also markedly inhibited the development of Fusarium wilt caused by F. oxysporum f.sp. lycopersici in tomato plants by treatment with 10 μg ml(-1) under greenhouse conditions. The efficacy of FP-1 against Fusarium wilt was comparable to that of the synthetic fungicide benomyl. An egfp -tagged strain of KPE62302H confirmed its ability to colonize tomato plants. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Disease control effect of strevertenes produced by Streptomyces psammoticus against tomato fusarium wilt.

    Science.gov (United States)

    Kim, Jeong Do; Han, Jae Woo; Lee, Sung Chul; Lee, Dongho; Hwang, In Cheon; Kim, Beom Seok

    2011-03-09

    During screening of microorganisms producing antifungal metabolites, Streptomyces psammoticus strain KP1404 was isolated. The culture extract of this strain showed potent disease control efficacy against Fusarium wilt on tomato plants. The antifungal metabolites ST-1 and ST-2 were isolated from the culture extract using a variety of chromatographic procedures. On the basis of MS and NMR spectrometric analysis, the structures of the antifungal active compounds ST-1 and ST-2 were determined to be the polyene antibiotics strevertene A and strevertene B, respectively. In vitro, strevertenes A and B showed inhibitory effects against the mycelial growth of Alternaria mali , Aspergillus oryzae , Cylindrocarpon destructans , Colletotrichum orbiculare , Fusarium oxysporum f.sp. lycopersici, and Sclerotinia sclerotiorum , even at concentrations of 4-16 μg/mL. Fusarium wilt development on tomato plants was strongly retarded by treatment with 1 μg/mL of these strevertenes. The disease control efficacies of strevertenes on Fusarium wilt were as remarkable as that of benomyl.

  9. The presence of a virulence locus discriminates Fusarium oxysporum isolates causing tomato wilt from other isolates.

    Science.gov (United States)

    van der Does, H Charlotte; Lievens, Bart; Claes, Loes; Houterman, Petra M; Cornelissen, Ben J C; Rep, Martijn

    2008-06-01

    Fusarium oxysporum is an asexual fungus that inhabits soils throughout the world. As a species, F. oxysporum can infect a very broad range of plants and cause wilt or root rot disease. Single isolates of F. oxysporum, however, usually infect one or a few plant species only. They have therefore been grouped into formae speciales (f.sp.) based on host specificity. Isolates able to cause tomato wilt (f.sp. lycopersici) do not have a single common ancestor within the F. oxysporum species complex. Here we show that, despite their polyphyletic origin, isolates belonging to f.sp. lycopersici all contain an identical genomic region of at least 8 kb that is absent in other formae speciales and non-pathogenic isolates, and comprises the genes SIX1, SIX2 and SHH1. In addition, SIX3, which lies elsewhere on the same chromosome, is also unique for f.sp. lycopersici. SIX1 encodes a virulence factor towards tomato, and the Six1, Six2 and Six3 proteins are secreted in xylem during colonization of tomato plants. We speculate that these genes may be part of a larger, dispensable region of the genome that confers the ability to cause tomato wilt and has spread among clonal lines of F. oxysporum through horizontal gene transfer. Our findings also have practical implications for the detection and identification of f.sp. lycopersici.

  10. Making headway in understanding pine wilt disease: what do we perceive in the postgenomic era?

    Science.gov (United States)

    Shinya, Ryoji; Morisaka, Hironobu; Takeuchi, Yuko; Futai, Kazuyoshi; Ueda, Mitsuyoshi

    2013-07-01

    The advent of next generation sequencing has revolutionized research approaches to biology by making entire genome sequences available and marking a new age in biology that has the potential to open innovative research avenues in various fields. Genome sequencing is now being applied in the fields of forest ecology and forest pathology, which previously had limited access to molecular techniques. One of the most advanced areas of progress is the study of "pine wilt disease", which is caused by the parasitic nematode, Bursaphelenchus xylophilus. The entire genome sequence of B. xylophilus was determined in 2011, and since then, proteomic studies have been conducted to understand the molecular basis of the parasitism and pathogenicity of B. xylophilus. These postgenomic studies have provided numerous molecular insights and greatly changed our understanding of the pathogenesis of pine wilt disease. Here, we review the recent advances in genomic and proteomic approaches that address some of the longstanding questions behind the pathogenesis of pine wilt disease and have identified future questions and directions in this regard. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. Growth of Verticillium longisporum in Xylem Sap of Brassica napus is Independent from Cultivar Resistance but Promoted by Plant Aging.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-09-01

    As Verticillium stem striping of oilseed rape (OSR), a vascular disease caused by Verticillium longisporum, is extending into new geographic regions and no control with fungicides exists, the demand for understanding mechanisms of quantitative resistance increases. Because V. longisporum is strictly limited to the xylem and resistance is expressed in the systemic stage post root invasion, we investigated a potential antifungal role of soluble constituents and nutritional conditions in xylem sap as determinants of cultivar resistance of OSR to V. longisporum. Assessment of biometric and molecular genetic parameters applied to describe V. longisporum resistance (net area under disease progress curve, stunting, stem thickness, plant biomass, and V. longisporum DNA content) showed consistent susceptibility of cultivar 'Falcon' in contrast to two resistant genotypes, 'SEM' and 'Aviso'. Spectrophotometric analysis revealed a consistently stronger in vitro growth of V. longisporum in xylem sap extracted from OSR compared with the water control. Further comparisons of fungal growth in xylem sap of different cultivars revealed the absence of constitutive or V. longisporum induced antifungal activity in the xylem sap of resistant versus susceptible genotypes. The similar growth of V. longisporum in xylem sap, irrespective of cultivar, infection with V. longisporum and xylem sap filtration, was correlated with about equal amounts of total soluble proteins in xylem sap from these treatments. Interestingly, compared with younger plants, xylem sap from older plants induced significantly stronger fungal growth. Growth enhancement of V. longisporum in xylem sap of aging plants was reflected by increased contents of carbohydrates, which was consistent in mock or V. longisporum-infected plants and independent from cultivar resistance. The improved nutritional conditions in the xylem of more mature plants may explain the late appearance of disease symptoms, which are observed only in

  12. Comparative microbiota assessment of wilted Italian ryegrass, whole crop corn, and wilted alfalfa silage using denaturing gradient gel electrophoresis and next-generation sequencing.

    Science.gov (United States)

    Ni, Kuikui; Minh, Tang Thuy; Tu, Tran Thi Minh; Tsuruta, Takeshi; Pang, Huili; Nishino, Naoki

    2017-02-01

    The microbiota of pre-ensiled crop and silage were examined using denaturing gradient gel electrophoresis (DGGE) and next-generation sequencing (NGS). Wilted Italian ryegrass (IR), whole crop corn (WC), and wilted alfalfa (AL) silages stored for 2 months were examined. All silages contained lactic acid as a predominant fermentation product. Across the three crop species, DGGE detected 36 and 28 bands, and NGS identified 253 and 259 genera in the pre-ensiled crops and silages, respectively. The NGS demonstrated that, although lactic acid bacteria (LAB) became prevalent in all silages after 2 months of storage, the major groups were different between crops: Leuconostoc spp. and Pediococcus spp. for IR silage, Lactobacillus spp. for WC silage, and Enterococcus spp. for AL silage. The predominant silage LAB genera were also detected by DGGE, but the presence of diverse non-LAB species in pre-ensiled crops was far better detected by NGS. Likewise, good survival of Agrobacterium spp., Methylobacterium spp., and Sphingomonas spp. in IR and AL silages was demonstrated by NGS. The diversity of the microbiota described by principal coordinate analysis was similar between DGGE and NGS. Our finding that analysis of pre-ensiled crop microbiota did not help predict silage microbiota was true for both DGGE and NGS.

  13. Ecological implications of Laurel Wilt infestation on Everglades Tree Islands, southern Florida

    Science.gov (United States)

    Snyder, James R.

    2014-01-01

    There is a long history of introduced pests attacking native forest trees in the United States (Liebhold and others, 1995; Aukema and others, 2010). Well-known examples include chestnut blight that decimated the American chestnut (Castanea dentata), an extremely important tree in the eastern United States, both as a food source for wildlife and humans and for the wood; Dutch elm disease that attacks native elms (Ulmus spp.), including those commonly planted as shade trees along city streets; and the balsam wooly adelgid (Adelges piceae), an insect that is destroying Fraser firs (Abies fraseri) in higher elevations of Great Smoky Mountains National Park. Laurel wilt, a fungal disease transmitted by the redbay ambrosia beetle (Xyleborus glabratus), is a 21st-century example of an introduced forest pest that attacks native tree species in the laurel family (Lauraceae) (Mayfield, 2007; Hulcr and Dunn, 2011).The introduction of laurel wilt disease has been traced to the arrival of an Asian ambrosia beetle (Xyleborus glabratus) at Port Wentworth, Georgia, near Savannah, in 2002, apparently accidently introduced in wooden shipping material (Mayfield, 2007). Within the next 2 years, it was determined that the non-native wood-boring insect was the vector of an undescribed species of fungus, responsible for killing large numbers of red bay (Persea borbonia) trees in the surrounding area. Dispersing female redbay ambrosia beetles drill into live trees and create tunnels in the wood. They carry with them fungal spores in specialized organs called mycangia at the base of each mandible and sow the spores in the tunnels they excavate. The fungus, since named Raffaelea lauricola (Harrington and others, 2008), is the food source for adults and larvae. The introduction of Raffaelea lauricola causes the host plant to react in such a way as to block the vascular tissue, resulting in loss of water conduction, wilt, and death (Kendra and others, 2013).Although first seen in red bay

  14. The effect of pH on the production of chitinolytic enzymes of Verticillium fungicola in submerged cultures.

    Science.gov (United States)

    Ramirez-Coutiño, Laura; Espinosa-Marquez, Jesús; Peter, Martin G; Shirai, Keiko

    2010-12-01

    Chitinase and N-acetylhexosaminidase activities in submerged cultures of Verticillium fungicola increased up to 5-fold and 2.5-fold, respectively when the pH of the culture medium was raised from 5 to 8. SDS-PAGE and zymograms of the freeze-dried crude enzyme obtained from the cultures indicated four chitin degrading proteins of M(w) 24, 40, 55 and 63 kDa, whereas isoelectric focusing displayed the separation of three chitin degrading enzymes with isoelectric points of 4.7, 6.8 and 10, as well as two N-acetylhexosaminidases having isoelectric points of 3.2 and 13. Freeze-dried crude enzyme was characterized for its ability to produce chito-oligosaccharides from chitosans. Matrix-assisted laser desorption ionization time of flight mass spectrometry analyses revealed that monomers as well as hetero-oligomers with degree of polymerization 4 were initially the main products, whereas oligomers with degree of polymerization 2-11 were detected after extended reaction times. 2010 Elsevier Ltd. All rights reserved.

  15. Manipulating inoculum densities of Verticillium dahliae and Pratylenchus penetrans with green manure amendments and solarization influence potato yield.

    Science.gov (United States)

    Macguidwin, A E; Knuteson, D L; Connell, T; Bland, W L; Bartelt, K D

    2012-05-01

    We used cover crops with demonstrated efficacy against Verticillium dahliae and Pratylenchus penetrans in combination with the biocidal practice of solarization to determine the importance of targeting both organisms for managing potato early dying, an issue relevant to the search for alternatives to soil fumigation. Two experiments were conducted in commercial fields using a split-plot design with cover crop treatments of rapeseed, marigold, forage pearl millet, sorghum-sudangrass, and corn as the main plot factor and solarization as the subplot factor. Cover crops were grown and solarization applied in year one, followed by potato in year two. The main effect of solarization was significant for reduced inoculum levels of both organisms in year two and increased tuber yields. The main effect of cover crop was also significant with lower population densities of P. penetrans following the marigold and millet treatments and of V. dahliae following rape and sorghum-sudangrass. The cover crop treatments influenced yield in only one of the experiments in the absence of solarization. The combinatorial effect of cover crops and solarization resulted in a wide range of pathogen population densities. Mean soil inoculum levels were negatively related to yield for V. dahliae in experiment 1, and for P. penetrans and the P. penetrans × V. dahliae interaction in both experiments.

  16. Suppression of the homeobox gene HDTF1 enhances resistance to Verticillium dahliae and Botrytis cinerea in cotton.

    Science.gov (United States)

    Gao, Wei; Long, Lu; Xu, Li; Lindsey, Keith; Zhang, Xianlong; Zhu, Longfu

    2016-05-01

    Development of pathogen-resistant crops, such as fungus-resistant cotton, has significantly reduced chemical application and improved crop yield and quality. However, the mechanism of resistance to cotton pathogens such as Verticillium dahliae is still poorly understood. In this study, we characterized a cotton gene (HDTF1) that was isolated following transcriptome profiling during the resistance response of cotton to V. dahliae. HDTF1 putatively encodes a homeodomain transcription factor, and its expression was found to be down-regulated in cotton upon inoculation with V. dahliae and Botrytis cinerea. To characterise the involvement of HDTF1 in the response to these pathogens, we used virus-induced gene silencing (VIGS) to generate HDTF1-silenced cotton. VIGS reduction in HDTF1 expression significantly enhanced cotton plant resistance to both pathogens. HDTF1 silencing resulted in activation of jasmonic acid (JA)-mediated signaling and JA accumulation. However, the silenced plants were not altered in the accumulation of salicylic acid (SA) or the expression of marker genes associated with SA signaling. These results suggest that HDTF1 is a negative regulator of the JA pathway, and resistance to V. dahliae and B. cinerea can be engineered by activation of JA signaling. © 2015 Institute of Botany, Chinese Academy of Sciences.

  17. Perturbations in the Primary Metabolism of Tomato and Arabidopsis thaliana Plants Infected with the Soil-Borne Fungus Verticillium dahliae.

    Directory of Open Access Journals (Sweden)

    Anja Buhtz

    Full Text Available The hemibiotrophic soil-borne fungus Verticillium dahliae is a major pathogen of a number of economically important crop species. Here, the metabolic response of both tomato and Arabidopsis thaliana to V. dahliae infection was analysed by first using non-targeted GC-MS profiling. The leaf content of both major cell wall components glucuronic acid and xylose was reduced in the presence of the pathogen in tomato but enhanced in A. thaliana. The leaf content of the two tricarboxylic acid cycle intermediates fumaric acid and succinic acid was increased in the leaf of both species, reflecting a likely higher demand for reducing equivalents required for defence responses. A prominent group of affected compounds was amino acids and based on the targeted analysis in the root, it was shown that the level of 12 and four free amino acids was enhanced by the infection in, respectively, tomato and A. thaliana, with leucine and histidine being represented in both host species. The leaf content of six free amino acids was reduced in the leaf tissue of diseased A. thaliana plants, while that of two free amino acids was raised in the tomato plants. This study emphasizes the role of primary plant metabolites in adaptive responses when the fungus has colonized the plant.

  18. PENGARUH INFESTASI VERTICILLIUM LECANII TERHADAP KEPARAHAN PENYAKIT KARAT DAUN KOPI PADA TANAMAN DAN KETERJADIAN KOLONINYA PADA DAUN

    Directory of Open Access Journals (Sweden)

    Cipta Ginting .

    2011-11-01

    Full Text Available Effect of infestation of Verticillium lecanii on the severity of coffee leaf rust on plants and the incidence of its colony on coffee leaves.  V. lecanii often antagonizes H. vastatrix on lesions caused by the pathogen on coffee leaves in the field.  The objectives of this study were to evaluate the efficacy of V. lecanii to control disease severity on coffee plants in a green house and to compare the incidence of V. lecanii colonies on coffee leaves naturally infested by V. lecanii in the field and that in the leaves with additional infestation in the laboratory.  For efficacy test and additional infestation in the laboratory, conidia were harvested from YMPD medium.  Suspension with 107 conidia ml-1 was sprayed into coffee foliage until both surfaces of the leaves were saturated with the suspension.  After the leaves were air dried, they were sprayed with urediospores (104 ml-1.  The results show that disease severity in plants treated with V. lecanii and control plants was not significantly different (P < 0.05, except that obtained at the fourth week when disease severity on the treated plants was significantly lower that that in control plants.  The number of V. lecanii colonies on coffee leaves naturally infested with the biocontrol agent was not increased by additional infestation with V. lecanii conidia in the laboratory.

  19. A highly sensitive single-tube nested PCR assay for the detection of Pineapple mealybug wilt associated virus-2 (PMWaV-2)

    Science.gov (United States)

    An assay was developed for the detection of Pineapple mealybug wilt associated virus-2 (PMWaV-2), an important factor in the etiology of mealybug wilt of pineapple. The assay combines reverse transcription of RNA isolated from pineapple with a specific and very sensitive, single, closed-tube nested ...

  20. Cepa de Trichoderma útil para el tratamiento y/o prevención de infecciones provocadas por hongos pertenecientes al género Verticillium

    OpenAIRE

    Barroso-Albarracín, Juan Bautista; Chaki, Mounira; Mercado-Blanco, Jesús; Valverde-Corredor, Antonio; López García, Antonio Alejandro

    2011-01-01

    La invención se refiere al uso de la cepa de hongos Trichoderma harzianum CECT 2413 para la prevención y/o tratamiento de infecciones de plantas y/o suelos provocadas por hongos fitopatógenos pertenecientes al género Verticíllium, preferiblemente por los patotipos defoliante o no defoliante de Verticillium dahliae, agente causante de la Verticilosis del olivo. Además, la invención propone el uso de esta cepa de hongos en combinación con otros hongos del género Trichoderma.

  1. In vitro effect of essential oils from aromatic and medicinal plants on mushroom pathogens: Verticillium fungicola var. fungicola, Mycogone perniciosa, and Cladobotryum sp.

    Directory of Open Access Journals (Sweden)

    Tanović Brankica

    2009-01-01

    Full Text Available Lavender, anise, chamomile, fennel, geranium, oregano, parsley, and sage essential oils were tested for their effectiveness against mushroom pathogens: Verticillium fungicola var. fungicola, Mycogone perniciosa, and Cladobotryum sp. Isolates were exposed to the volatile phase of the oils and then ventilated in order to determine if the effect of the oil was lethal to the pathogen. Oregano and geranium oils were the most toxic, having a fungicidal effect at 0.02-0.08 μl/ml of air, depending on the pathogen. Oregano oil was characterized by high content of carvacrol and thymol, while citranelol and geraniol were the main components of geranium oil.

  2. Effects of stage of maturity at harvest, wilting and LAB inoculant on aerobic stability of wheat silages

    DEFF Research Database (Denmark)

    Weinberg, Z.G.; Khanal, Prabhat; Chen, Y.

    2010-01-01

    spoilage indicators. The inoculant enhanced CO production in the silages prepared from the DC wheat of the flowering and milk stages, as compared with the respective non-inoculated control silages which contained high concentrations of VFA. However, in the wilted silages which contained less VFA, both......The objective was to study effects of cultivar, stage of maturity at harvest, wilting, and addition of lactic acid bacterial (LAB) inoculant at ensiling, and their interactions, on the aerobic stability of wheat silages. Wheat of two cultivars, harvested at the flowering or the milk stage...... of maturity were ensiled in mini-silos, either directly after cutting (DC) or after wilting (W). After 2-7 months of storage, silages were subjected to a 7-day aerobic stability test during which changes in chemical composition, dry matter (DM) and neutral detergent fiber (aNDF) digestibility, and temperature...

  3. Grafted eggplant yield, quality and growth in infested soil with Verticillium dahliae and Meloidogyne incognita Produção, qualidade e crescimento de beringela enxertada, em solo infestado com Verticillium dahliae e Meloidogyne incognita

    Directory of Open Access Journals (Sweden)

    Sebahattin Çürük

    2009-12-01

    Full Text Available The objective of this work was to evaluate the effect of grafting (onto Solanum torvum Sw. on plant growth, yield and fruit quality of the Pala and Faselis eggplant (Solanum melongena L. cultivars, grown in a soil infested with Verticillium dahliae Kleb. and Meloidogyne incognita, or in noninfested soil. Soil infestation decreased yield, plant height, final above-ground biomass, and also reduced fruit mean weight and shoot dry weight depending on cultivar or grafting. Grafting decreased fruit oxalic acid and the soluble solid contents, and increased mean fruit weight, depending on cultivar and soil infestation. Grafting also reduced the negative effects of the pathogens on disease index, plant height and shoot dry weight. Cultivar Pala was more vigorous than Faselis, and S. torvum was a vigorous rootstock. The combination of a vigorous rootstock with a weak cultivar (Faselis is more profitable than that of a vigorous rootstock and a vigorous cultivar (Pala. Using S. torvum as a rootstock for cultivar Faselis, grown in soil infested with the pathogens, is most likely to be useful in conventional and low-input sustainable horticulture, since grafting increases protection against the pathogens, and reduces the losses in quality and yield.O objetivo deste trabalho foi avaliar o efeito sobre a altura de planta, a produção e a qualidade de frutos do enxerto das cultivares de beringela (Solanum melongena L. Pala e Faselis em Solanum torvum Sw., quando cultivadas em solo infestado com Verticillium dahliae e Meloidogyne incognita ou em solo não infestado. A infestação do solo reduziu a produção, altura da planta, biomassa da parte aérea, massa média dos frutos, massa de matéria seca da parte aérea, conforme a cultivar utilizada e a enxertia. A enxertia reduziu os conteúdos de ácido oxálico e de sólidos solúveis e aumentou a massa média de frutos, conforme a cultivar ou a presença do patógeno no solo. A enxertia também reduziu o efeito

  4. Unravelling aspects of spatial and temporal distribution of Verticillium dahliae in olive, maple and ash trees and improvement of detection methods

    NARCIS (Netherlands)

    Keykhasaber, Mojtaba

    2017-01-01

    Vascular wilts caused by xylem-colonizing pathogens are among the most devastating plant diseases that affect a wide range of plant species worldwide. Information on the distribution of V. dahliae in infected trees helps to design an appropriate and efficient sampling method for reliable detection

  5. Analyses of Fusarium wilt race 3 resistance in Upland cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Abdullaev, Alisher A; Salakhutdinov, Ilkhom B; Egamberdiev, Sharof Sh; Kuryazov, Zarif; Glukhova, Ludmila A; Adilova, Azoda T; Rizaeva, Sofiya M; Ulloa, Mauricio; Abdurakhmonov, Ibrokhim Y

    2015-06-01

    Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV) Atk. Sny & Hans] represents a serious threat to cotton (Gossypium spp.) production. For the last few decades, the FOV pathogen has become a significant problem in Uzbekistan causing severe wilt disease and yield losses of G. hirsutum L. cultivars. We present the first genetic analyses of FOV race 3 resistance on Uzbek Cotton Germplasm with a series of field and greenhouse artificial inoculation-evaluations and inheritance studies. The field experiments were conducted in two different sites: the experimental station in Zangiota region-Environment (Env) 1 and the Institute of Cotton Breeding (Env-2, Tashkent province). The Env-1 was known to be free of FOV while the Env-2 was known to be a heavily FOV infested soil. In both (Env-1 and Env-2) of these sites, field soil was inoculated with FOV race 3. F2 and an F3 Upland populations ("Mebane B1" × "11970") were observed with a large phenotypic variance for plant survival and FOV disease severity within populations and among control or check Upland accessions. Wilt symptoms among studied F2 individuals and F3 families significantly differed depending on test type and evaluation site. Distribution of Mendelian rations of susceptible (S) and resistant (R) phenotypes were 1S:1R field Env-1 and 3S:1R field Env-2 in the F2 population, and 1S:3R greenhouse site in the F3 population. The different segregation distribution of the Uzbek populations may be explained by differences in FOV inoculum level and environmental conditions during assays. However, genetic analysis indicated a recessive single gene action under high inoculum levels or disease pressure for FOV race 3 resistance. Uzbek germplasm may be more susceptible than expected to FOV race 3, and sources of resistance to FOV may be limited under the FOV inoculum levels present in highly-infested fields making the breeding process more complex.

  6. Control of tomato early blight and wilt using aqueous extract of neem leaves

    Directory of Open Access Journals (Sweden)

    Naziha M. HASSANEIN

    2010-09-01

    Full Text Available The effect of neem (Azadiracta indica leaf extract against Alternaria solani and Fusarium oxysporum, the causal agents of early blight and wilt of tomato plants (Lycopersicon esculentum Mill. respectively, was studied. Concentrations (5, 10 and 20% of aqueous neem extract suppressed mycelial growth of both pathogenic fungi and the degree of suppression gradually increased with increasing concentration. A concentration of 20% aqueous neem leaf extract sprayed on tomato plants lowered the incidence of Alternaria early blight from 53.2 to 42.5% after two weeks and from 100 to 79.2% after 4 weeks. Spraying plus irrigation with the same extract lowered the severity of Alternaria early blight from 26.8 to 11.4% after 2 weeks and from 61.7 to 17.9% after 4 weeks (control ratio of 43.71% after 4 weeks. For F. oxysporum wilt, germination of tomato seeds was highest in pots containing the negative control (soil free of pathogen and in pots irrigated with the aqueous neem extract. The lowest disease incidence (19.04% was obtained in pots treated with the pathogen and irrigated with aqueous neem extract, where an 81% control of Fusarium wilt was achieved. Growth parameters of tomato (shoot and root length, number of leaves, fresh and dry weight of shoots and roots were studied 4, 6 and 8 weeks after sowing in the presence of the pathogens. There was a significant gradual increase in growth parameters when the plants were sprayed and irrigated with aqueous neem extract with the greatest improvement recorded 8 weeks after sowing.

  7. Effects of wilting and lactic acid bacteria inoculation on fermentation quality of white lupin and fababean silages

    Directory of Open Access Journals (Sweden)

    G. Borreani

    2010-04-01

    Full Text Available Fababeans and lupins are short-term catch crops with a high crude protein content, which provide a high forage yield in a short growing period. Legumes are difficult to conserve as silages because of their low water soluble carbohydrates content (WSC and high buffer capacity. To our knowledge, little information is available on the ensiling of fababeans and lupins in Southern Europe. The research was carried out in Lodi (Italy in order to evaluate the effects of wilting and inoculation with lactic acid bacteria (LAB on fermentation characteristics of the resulting silages. The data show that both wilting and LAB inoculant significantly improved fermentation quality of the legumes silages.

  8. EFFECT OF DIFFERENT ORGANIC AMENDMENTS ON Fusarium oxysporum f.sp ciceri CAUSING CHICK PEA WILT

    OpenAIRE

    S.Ranjitha Rani; S.S.Mane

    2014-01-01

    Chickpea (Cicer arietinumL.) is one of the most important legumes grown in Asia. Though the area under this crop is more, the average yield per hectare is low because of several biotic and abiotic factors. Among them, the wilt caused by Fusarium oxysporumf.sp. ciceriis most destructive seed and soil borne disease. (Haware et al., 1986) which threatens successful cultivation of chickpea and causes severe losses in chickpea growing areas. (Grewal et al.,1974b and Singh et al.,1977.) The organic...

  9. Pseudomonas sp. strain MF30 suppresses Fusarium wilt of tomato in vivo

    OpenAIRE

    Berndt Gerhardson; Idress H. Attitalla; P. Maria Johansson; Sture Brishammar

    2001-01-01

    In a search of bacterial biological control agents, 50 bacterial isolates collected from roots of wild plants in northern Sweden were tested in vivo for suppression of wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici. Tomato plants were sown in 10-cm-diam. pots and after 21 d 7 ml of bacterial suspension (ca. 2x109 cfu ml-1) was poured into the soil around each plant. Two days later, 10 ml of pathogen suspension was soil-inoculated (106 conidia ml-1) around the same ...

  10. Evaluation of peanut genotypes for resistance to Tomato spotted wilt virus by mechanical and thrips inoculation.

    OpenAIRE

    NASCIMENTO, L.C. do; PENSUK, V.; COSTA, N.P. da; ASSIS FILHO, F.M. de; PIO-RIBEIRO, G.; DEOM, C.M.; Sherwood, J.

    2006-01-01

    The objective of this work was to evaluate the reactions of three peanut breeding lines (IC-10, IC-34, and ICGV 86388) to Tomato spotted wilt virus (TSWV) by mechanical and thrips inoculation, under greenhouse conditions, and compare them to the reactions of cultivars SunOleic, Georgia Green, and the breeding line C11-2-39. TSWV infection by mechanical inoculation was visually assessed using an index ranging from 0 (no symptoms) to 4 (apical death). Enzyme-linked immunosorbent assay was used ...

  11. Effect of tiazofurin on tomato plants infected with tomato spotted wilt virus.

    Science.gov (United States)

    Caner, J; Amélia, M; Alexandre, V; Vicente, M

    1984-12-01

    Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) was examined for its activity against tomato-spotted wilt virus (TSWV) in tomato plants. Solutions containing 50, 100, 200, 400 and 800 mg/l of the drug were sprayed onto the leaves. The results showed that 100 and 200 mg/l were the most efficient concentrations to suppress TSWV infection, thereby delaying the appearance of systemic symptoms. The drug was more effective in controlling TSWV infection when applied after than before virus inoculation. The results suggest that tiazofurin can be used as an efficient antiviral drug in the treatment of TSWV-infected tomato plants.

  12. The effect of wide swathing on wilting times and nutritive value of alfalfa haylage.

    Science.gov (United States)

    Kung, L; Stough, E C; McDonell, E E; Schmidt, R J; Hofherr, M W; Reich, L J; Klingerman, C M

    2010-04-01

    On 3 consecutive cuttings, alfalfa from a single field was mowed with a John Deere 946 mower-conditioner (4-m cut width; Moline, IL) to leave narrow swaths (NS) ranging from 1.2 to 1.52 m wide (30-37% of cutter bar width) and wide swaths (WS) ranging from 2.44 to 2.74 m wide (62-67% of cutter bar width). Samples were collected from windrows and dry matter (DM) was monitored during wilting until a target of 43 to 45% DM was obtained. Forage from random windrows (n=4-6) was harvested by hand, chopped through a forage harvester before being packed in replicated vacuum-sealed bags, and allowed to ensile for 65 d. There was no swath width x cutting interaction for any parameter tested. Over all cuttings, the resulting silage DM was not different between the NS silage (43.8%) and the WS silage (44.9%). However, wide swathing greatly reduced the time of wilting before making silage. The hours of wilting time needed to reach the targeted DM for the NS silage compared with the WS silage at cuttings 1, 2, and 3 were 50 versus 29, 54 versus 28, and 25 versus 6, respectively. At the time of ensiling, the WS silage had more water-soluble carbohydrates (5.1%) than did the NS silage (3.7%). The WS silage had a lower pH (4.58) than did the NS silage (4.66), but swath width did not affect fermentation end products (lactic acid, acetic acid, and ethanol). The NS silage had more NH(3)-N (0.26%) than did the WS silage (0.21%). Wide swathing did not affect the concentration of ash or the digestibility of NDF, but it lowered the N content (NS=3.45%; WS=3.23%) and increased the ADF content (NS=39.7%; WS=40.9%) of the resulting silage. Wide swathing can markedly reduce the time that alfalfa must wilt before it can be chopped for silage, but under good conditions, as in this study, the resulting silage quality was generally not improved. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Incidences and severity of vascular wilt in Acacia mangium plantations in Sabah, Malaysia

    Science.gov (United States)

    Maid, Mandy; Ratnam, Wickneswari

    2014-09-01

    This study aimed to evaluate the incidences and severity of vascular wilt disease associated with dieback in stands of commercial Acacia mangium plantations. The study revealed that the prevalence of the symptoms is high between 50 to 60% in two plantations, where it is found scattered in the plots that were surveyed. The incidence of the disease in each plot is low between 0 to 6%. The disease symptoms were more often found where the symptom syndrome in a chronic (level 3) or critical state (level 4). This suggests that the causal pathogen has the ability to penetrate into the tissues of the plants and only display symptoms at the latest stage.

  14. CERATOCYSTIS WILT IN ‘UBÁ’ AND ‘DURA’ MANGO TREES UNDER WATER DEFICIT

    OpenAIRE

    SILVA, SAULO DAVID REZENDE DA; Siqueira,Dalmo Lopes de; SALOMÃO, LUIS CARLOS CHAMHUM; Cecon, Paulo Roberto; Alfenas,Acelino Couto

    2017-01-01

    ABSTRACT The occurrence of water stress in mango trees grown in orchards located in semi-arid climates in Brazil is frequent. Water stress caused to plants may predispose them to the incidence of fungal diseases. The aim of this study was to evaluate the effect of water deficit on the incidence and severity of Ceratocystis wilt in mango trees considered resistant. Seedlings of ‘Ubá’ and ‘Dura’ were kept in pots and submitted to different water stress levels and inoculated with Ceratocystis f...

  15. Diversity, Pathogenicity, and Current Occurrence of Bacterial Wilt BacteriumRalstonia solanacearumin Peru.

    Science.gov (United States)

    Gutarra, Liliam; Herrera, Juan; Fernandez, Elizabeth; Kreuze, Jan; Lindqvist-Kreuze, Hannele

    2017-01-01

    The current bacterial wilt infestation level in the potato fields in the Peruvian Andes was investigated by collecting stem samples from wilted plants and detecting Ralstonia solanacearum . In total 39 farmers' fields located in the central and northern Peru between the altitudes 2111 and 3742 m above sea level were sampled. R. solanacearum was detected in 19 fields, and in 153 out of the 358 samples analyzed. Phylogenetic analysis using the partial sequence of the endoglucanase gene on strains collected in Peru between 1966 and 2016 from potato, pepper, tomato, plantain or soil, divided the strains in phylotypes I, IIA, and IIB. The Phylotype IIB isolates formed seven sequevar groups including the previously identified sequevars 1, 2, 3, 4, and 25. In addition to this, three new sequevars of phylotype IIB were identified. Phylotype IIA isolates from Peru clustered together with reference strains previously assigned to sequevars 5, 39, 41, and 50, and additionally one new sequevar was identified. The Phylotype I strain was similar to the sequevar 18. Most of the Peruvian R. solanacearum isolates were IIB-1 strains. In the old collection sampled between 1966 and 2013, 72% were IIB-1 and in the new collection at 2016 no other strains were found. The pathogenicity of 25 isolates representing the IIA and IIB sequevar groups was tested on potato, tomato, eggplant and tobacco. All were highly aggressive on potato, but differed in pathogenicity on the other hosts, especially on tobacco. All IIA strains caused latent infection on tobacco and some strains also caused wilting, while IIB strains caused only few latent infections on this species. In conclusion, high molecular diversity was found among the R. solanacearum strains in Peru. Most of the variability was found in areas that are no longer used for potato cultivation and thus these strains do not pose a real threat for potato production in the country. Compared to the previous data from the 1990s, the incidence of

  16. Diversity, Pathogenicity, and Current Occurrence of Bacterial Wilt Bacterium Ralstonia solanacearum in Peru

    Directory of Open Access Journals (Sweden)

    Liliam Gutarra

    2017-07-01

    Full Text Available The current bacterial wilt infestation level in the potato fields in the Peruvian Andes was investigated by collecting stem samples from wilted plants and detecting Ralstonia solanacearum. In total 39 farmers’ fields located in the central and northern Peru between the altitudes 2111 and 3742 m above sea level were sampled. R. solanacearum was detected in 19 fields, and in 153 out of the 358 samples analyzed. Phylogenetic analysis using the partial sequence of the endoglucanase gene on strains collected in Peru between 1966 and 2016 from potato, pepper, tomato, plantain or soil, divided the strains in phylotypes I, IIA, and IIB. The Phylotype IIB isolates formed seven sequevar groups including the previously identified sequevars 1, 2, 3, 4, and 25. In addition to this, three new sequevars of phylotype IIB were identified. Phylotype IIA isolates from Peru clustered together with reference strains previously assigned to sequevars 5, 39, 41, and 50, and additionally one new sequevar was identified. The Phylotype I strain was similar to the sequevar 18. Most of the Peruvian R. solanacearum isolates were IIB-1 strains. In the old collection sampled between 1966 and 2013, 72% were IIB-1 and in the new collection at 2016 no other strains were found. The pathogenicity of 25 isolates representing the IIA and IIB sequevar groups was tested on potato, tomato, eggplant and tobacco. All were highly aggressive on potato, but differed in pathogenicity on the other hosts, especially on tobacco. All IIA strains caused latent infection on tobacco and some strains also caused wilting, while IIB strains caused only few latent infections on this species. In conclusion, high molecular diversity was found among the R. solanacearum strains in Peru. Most of the variability was found in areas that are no longer used for potato cultivation and thus these strains do not pose a real threat for potato production in the country. Compared to the previous data from the 1990s

  17. [Population dynamics and antagonism toward Fusarium oxysporium f. sp. Vasinfectum. and Verticillium dahliae Kleb of endophytic bacteria from cotton].

    Science.gov (United States)

    Li, Chunhong; Deng, Yuanyu; Zhao, Mingwen; Tang, Canming; Li, Shunpeng; Lv, Haiwei

    2009-09-01

    To explore population dynamics of endophytic bacteria and obtain antagonistic endophytic bacteria toward Verticillium dahliae Kleb (Vd), Fusarium oxysporium f. sp. Vasinfectum (Fov) from cotton. Root, stem and leaf samples were surface-disinfested, and subsequently used to isolate endophytic bacteria by diluting plate counting method. We assayed antagonism of the isolated endophytic bacteria toward three pathogens: Vd (V107, which is a highly virulent defoliating isolate and V396, which is a mildly virulent non-defoliating isolate), Fov (F108) using a dual culture method, and analyzed the 16S rDNA sequence of doubly antagonistic endophytic bacteria (DAEB) isolates toward both Vd and Fov. The population size of endophytic bacteria in root was significantly larger than that in leaf and stem. The populations at seedling stage were generally lower than those at the flowering/maturing stage in root, the populations in stem and leaf were fluctuant at different development stages, but variation law was not observed obviously. Furthermore, although no significant differences of the population densities in root were found among 6 cotton cultivars, the population densities in stem and leaf showed cultivar differences. The proportion of endophytic bacteria antagonizing Vd (V107, V396) and Fov (F108) in root was higher than that in stem/leaf, moreover, the amount of endophytic bacteria antagonizing toward V107 was less than that toward V396/F108. Based on 16S rDNA sequence analysis, all 44 DAEB isolates consisted of two phyla, i.e., Bacteroidetes (1 out of 44) and Proteobacteria (43 out of 44), and fell into 8 genera. The genus enterobacter (18 out of 44) and Pantoea (15 out of 44) were predominant. Notably, ten DAEB isolates demonstrated cotton. Endophytic bacteria in cotton could serve as a pool for discovering biocontrol agent toward cotton pathogens.

  18. Secretory proteins are delivered to the septin-organized penetration interface during root infection by Verticillium dahliae

    Science.gov (United States)

    Zhou, Ting-Ting; Zhao, Yun-Long

    2017-01-01

    Successful infection of the host requires secretion of effector proteins to evade or suppress plant immunity. Secretion of effectors in root-infecting fungal pathogens, however, remains unexplored. We previously reported that Verticillium dahliae, a root-infecting phytopathogenic fungus, develops a penetration peg from a hyphopodium to infect cotton roots. In this study, we report that a septin ring, requiring VdSep5, partitions the hyphopodium and the invasive hypha and form the specialized fungus-host interface. The mutant strain, VdΔnoxb, in which NADPH oxidase B (VdNoxB) is deleted, impaired formation of the septin ring at the hyphal neck, indicating that NADPH oxidases regulate septin ring organization. Using GFP tagging and live cell imaging, we observed that several signal peptide containing secreted proteins showed ring signal accumulation/secretion at the penetration interface surrounding the hyphal neck. Targeted mutation for VdSep5 reduced the delivery rate of secretory proteins to the penetration interface. Blocking the secretory pathway by disrupting the vesicular trafficking factors, VdSec22 and VdSyn8, or the exocyst subunit, VdExo70, also arrested delivery of the secreted proteins inside the hyphopodium. Reduced virulence was observed when cotton roots were infected with VdΔsep5, VdΔsec22, VdΔsyn8 and VdΔexo70 mutants compared to infection with the isogenic wild-type V592. Taken together, our data demonstrate that the hyphal neck is an important site for protein secretion during plant root infection, and that the multiple secretory routes are involved in the secretion. PMID:28282450

  19. Crescimento e esporulação de isolados de Verticillium lecanii sob diferentes condições nutricionais

    Directory of Open Access Journals (Sweden)

    Barbosa Claudio Camargo

    2002-01-01

    Full Text Available O objetivo deste trabalho foi determinar as melhores condições de crescimento e esporulação de dois isolados de Verticillium lecanii (Zimm. Viégas, cultivados em vários meios de cultura, fontes de C, fontes orgânicas e inorgânicas de N e relações C:N. Após 20 dias de cultivo, BDA e Meio Completo mostraram ser os melhores meios de cultura, e a lactose e o amido foram as fontes de C que mais favoreceram o crescimento dos isolados JAB 02 e JAB 45, respectivamente; baixa esporulação foi apresentada por JAB 02, enquanto JAB 45 obteve boa esporulação em glicose e maltose. JAB 02 desenvolveu melhor quando a fonte orgânica de N era casitona; JAB 45 obteve bom desenvolvimento em presença de casitona e peptona, mas houve pouca esporulação em presença de triptona e caseína hidrolisada. As fontes inorgânicas de N que favoreceram o melhor desenvolvimento dos isolados foram (NH42HPO4 e NaNO3, porém, JAB 02 apresentou baixa esporulação. Entre as relações C:N analisadas, JAB 02 obteve melhor crescimento na relação 60:1 e JAB 45 nas relações 5:1, 10:1 e 20:1; baixa esporulação foi obtida por JAB 02 nas relações testadas, mas não se verificou efeito da relação C:N do meio sobre a esporulação dos isolados.

  20. Multilocus genotyping based species identification of entomopathogenic fungi of the genus Lecanicillium (=Verticillium lecanii s.l.).

    Science.gov (United States)

    Mitina, Galina; Kazartsev, Igor; Vasileva, Aleksandra; Yli-Mattila, Tapani

    2017-11-01

    Mitochondrial gene NADH dehydrogenase subunit 1 (nad1), β-tubulin gene, and elongation factor 1-alpha (tef) were used to characterize and to identify 42 Lecanicillum spp. isolates (former complex species Verticillium lecanii Zimm. Viegas) and to study the phylogenetic relationships in this group. Within the isolates under investigation, Lecanicillium muscarium was the most common species (about 70% of all isolates, collected on the different hosts, predominantly on the insects from the order Hemiptera). Based on nad1 sequencing four main molecular haplotypes were revealed. All four haplotypes have Holarctic origin. Most of them were isolated in the Central part of Russia. One haplotype showed a specific association with the certain geographical area, limited to southwest Georgia and the Krasnodar Territory. For most strains their affiliation to species L. muscarium, L. longisporum, L. psalliotae, L. pissodes were confirmed by the phylogenetic tree, based on the combined sequences of nad1, β-tub, and tef genes. Only five strains of haplotype C and strain F-2643 could not be identified to any present Lecanicillium species and their position remains ambiguous. Thus, the use of multilocus molecular approach based on these genes was useful to identify the Lecanicillium species. Inter-simple sequence repeat (ISSR) study evaluated a high diversity among the L. muscarium strains. The topology of the NJ-tree based on the ISSR-PCR markers has shown the genetic relationships with the support values 62-91% between L. muscarium isolates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. RabGAP22 is required for defense to the vascular pathogen Verticillium longisporum and contributes to stomata immunity.

    Directory of Open Access Journals (Sweden)

    Jonas Roos

    Full Text Available Verticillium longisporum is a soil-borne pathogen with a preference for plants within the family Brassicaceae. Following invasion of the roots, the fungus proliferates in the plant vascular system leading to stunted plant growth, chlorosis and premature senescence. RabGTPases have been demonstrated to play a crucial role in regulating multiple responses in plants. Here, we report on the identification and characterization of the Rab GTPase-activating protein RabGAP22 gene from Arabidopsis, as an activator of multiple components in the immune responses to V. longisporum. RabGAP22Pro :GUS transgenic lines showed GUS expression predominantly in root meristems, vascular tissues and stomata, whereas the RabGAP22 protein localized in the nucleus. Reduced RabGAP22 transcript levels in mutants of the brassinolide (BL signaling gene BRI1-associated receptor kinase 1, together with a reduction of fungal proliferation following BL pretreatment, suggested RabGAP22 to be involved in BL-mediated responses. Pull-down assays revealed serine:glyoxylate aminotransferase (AGT1 as an interacting partner during V. longisporum infection and bimolecular fluorescence complementation (BiFC showed the RabGAP22-AGT1 protein complex to be localized in the peroxisomes. Further, fungal-induced RabGAP22 expression was found to be associated with elevated endogenous levels of the plant hormones jasmonic acid (JA and abscisic acid (ABA. An inadequate ABA response in rabgap22-1 mutants, coupled with a stomata-localized expression of RabGAP22 and impairment of guard cell closure in response to V. longisporum and Pseudomonas syringae, suggest that RabGAP22 has multiple roles in innate immunity.

  2. Cytopathological characteristics of tomato spotted wilt virus isolates

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    Anna Rudzińska-Langwald

    2014-01-01

    Full Text Available The electron microscopy study revealed that four examined virus isolates in the cells of the infected host plant produced different inclusions depending on the virus isolate and the time of passaging by mechanical transmission. Numerous virus particle inclusions as well as viroplasm and filamentous inclusions typical for TSWV were present in the plant cells infected with TSWV isolate (PPR. This isolate was kept in N. rustica by 4 mechanical transmissions. A similar virus isolate but maintained for 2 years by mechanical transmission in Nicotiana plants (TI produced virus particle inclusions as well as amorphous inclusions typical for defective isolates. In plant cells infected with the same isolate but maintained by mechanical transmission one year longer (T2 no virus particle inclusions were produced. In the amorphous inclusions produced by this isolate virus particles were seen, but they were not surrounded by additional membrane. The isolate G induced only amorphous inclusions dispersed within the cytoplasm of infected cells. No virus particles were seen in the amorphous inclusions. The mechanical transmission of TSWV isolates in N. rustica plants reduced the number of virus particles present in the cytoplasm. The defectivenes of the isolate cause also the appearance of a new type of inclusion - the amorphous inclusions.

  3. GENETIC VARIABILITY ASSESSMENT OF FUSARIUM WILT PATHOGEN RACES AFFECTING CHICKPEA USING MOLECULAR MARKERS

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    Jhuma Datta

    2013-06-01

    Full Text Available Genetic diversity in Chickpea wilt pathogen has been characterized using 14 isolates of Fusarium oxysporum f. sp. ciceri (foc collected from major pulse growing regions of India. Out of 247 bands produced by 24 Random Amplified Polymorphic DNA (RAPD primers in Foc isolates, 210 (85% were polymorphic. A maximum of 14 amplicons were generated by primer OPF 05 whereas minimum 7 amplicons were generated by primer K7. A total of 24 alleles were produced by twelve simple sequence repeat (SSR primers with an average of two alleles per marker in foc isolates. The maximum number of 4 alleles was obtained with primer SSR 12. SSR amplicon size ranged from 100 to 400 bp. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA cluster analysis based on RAPD and SSR profiles grouped the fourteen foc isolates into four major clusters. The universal Inter Transcribed Spacer (ITS primer pair amplified 630 bp bands in all fourteen foc isolates while significant length polymorphism was obtained only when analysed by restriction digestion with EcoRI and MspI enzymes. The cluster analysis of ITS-RFLP grouped all 14 Foc isolates into three major clusters. The cluster analysis using RAPD, SSR and ITS-RFLP markers show the grouping of Fusarium isolates strictly according to their cultural characteristics and degree of pathogenicity and not the geographical origin. This information will be helpful for pathologists and plant breeders to design effective resistance breeding programs in chickpea taking into account the diversity in wilt pathogen.

  4. Effect of silicates and electrical conductivity on Fusarium wilt of hydroponically grown lettuce.

    Science.gov (United States)

    Chitarra, W; Pugliese, M; Gilardi, G; Gullino, M L; Garibaldi, A

    2013-01-01

    Silicon can stimulate natural defense mechanisms in plants, reducing foliar diseases like powdery arid downy mildew on several crops, including lettuce. The effect of silicate on Fusarium wilt, caused by Fusarium oxysporum f. sp. lactucae was evaluated under greenhouse conditions on lettuce grown in soilless systems. Silicon, as potassium silicate, was added at 100 mg L(-1) of nutrient solution at three levels of electrical conductivity; 1.5-1.6 mS cm(-1) (E.C.1), 3.0-3.2 mS cm(-1) (E.C.2) and 4-4.2 mS cm(-1) (E.C.3). Pots containing lettuce plants were first inoculated with F. oxysporum f. sp. lactucae (3x10(5) chlamidospores ml(-1)) 15-20 days before transplanting. Disease severity and physiological parameters, including chlorophyll content, were analyzed weekly after transplanting. The addition of potassium silicate slightly reduced Fusarium wilt, at all levels of electrical conductivity under study, compared to the control. On the contrary, the increase of electrical conductivity of the nutrient solution showed no effect on the disease. The use of silicon was previously demonstrated to significantly reduce downy mildew on lettuce in soilless systems, and in this trial it demonstrated to slightly reduce disease severity of an important soil-borne pathogen like F. oxysporum f. sp. lactucae, suggesting the possibility to apply it successfully in soilless crops.

  5. VEGETATIVE COMPATIBILITY GROUPS OF FUSARIUM OXYSPORUM, THE CAUSAL ORGANISM OF VASCULAR WILT ON ROSELLE IN MALAYSIA

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    K.H. Ooi

    1999-01-01

    Full Text Available Forty strains of Fusarium oxysporvm isolated from roselle (Hibiscus sabdariffa var. sabdariffa showing vascular wilt symptoms in three states (Terengganu, Penang and Ipoh in the northern Malaysian Peninsula were used to investigate the vegetative co mpatibility. Nitrate-nonutilizing (nil mutants were recovered from all the strains tested and subsequently used to study vegetative compatibility groups (VCG within the population by nit mutants pairings on minimal medium. Thirteen VCGs were found and none were vegetatively compatible with those of other formae speciales (f. spp. such as asparagi and cubense, and non-pathogenic strains from paddy and oil palm. The results indicate that there is substantial genetic diversity in F. oxysporum that causes vascular wilt disease on roselle as reflected by multiple VCGs, but the distribution of strains into the VCGs is not even as there are 26 representatives in VCG-1001M, two in VCG-1003M and VCG-1013M and only one in the other VCGs. This study may provide new insight into the establishment of a new forma specialis off. oxysporum.

  6. The succession pattern of soil microbial communities and its relationship with tobacco bacterial wilt.

    Science.gov (United States)

    Niu, Jiaojiao; Rang, Zhongwen; Zhang, Chao; Chen, Wu; Tian, Feng; Yin, Huaqun; Dai, Linjian

    2016-10-06

    The interaction mechanism between crop and soil microbial communities is a key issue in both agriculture and soil ecology. However, how soil microbial communities respond to crop planting and ultimately affect crop health still remain unclear. In this research, we explored how soil microbial communities shifted during tobacco cultivation under different rotation systems (control, maize rotation, lily rotation and turnip rotation). Our analyses showed that soil microbial communities had a general response pattern to tobacco planting, as the abundances of Proteobacteria and Planctomycetes increased while Acidobacteria and Verrucomicrobia decreased during tobacco cultivation, no matter which rotation system was adopted. Notably, tobacco decreased the diversity and co-occurrence of soil microorganisms, but maize rotation might suppress tobacco bacterial wilt by alleviating the decrease in biodiversity and co-occurrence. Molecular ecological network analysis indicated that there was stronger competition between potential disease suppressive (e.g., Acidobacteria) and inducible bacteria (e.g., Chloroflexi) in maize rotation systems. Both soil properties (e.g., pH, Ca content) and microbial communities of tobacco mature period depended on their counterparts of fallow period, and all these factors shaped tobacco disease comprehensively. Both soil microbial communities of fallow stage and tobacco selection shaped the communities of tobacco mature stage. And effective rotation crop (maize) could decrease the incidence of tobacco bacterial wilt by alleviating the decrease in diversity and co-occurrences of microbial populations. This study would deepen our understanding about succession mechanism of soil microbial communities during crop cultivation and their relationship with crop health.

  7. An Integrated Insight into the Relationship between Soil Microbial Community and Tobacco Bacterial Wilt Disease.

    Science.gov (United States)

    Yang, Hongwu; Li, Juan; Xiao, Yunhua; Gu, Yabing; Liu, Hongwei; Liang, Yili; Liu, Xueduan; Hu, Jin; Meng, Delong; Yin, Huaqun

    2017-01-01

    The soil microbial communities play an important role in plant health, however, the relationship between the below-ground microbiome and above-ground plant health remains unclear. To reveal such a relationship, we analyzed soil microbial communities through sequencing of 16S rRNA gene amplicons from 15 different tobacco fields with different levels of wilt disease in the central south part of China. We found that plant health was related to the soil microbial diversity as plants may benefit from the diverse microbial communities. Also, those 15 fields were grouped into 'healthy' and 'infected' samples based upon soil microbial community composition analyses such as unweighted paired-group method with arithmetic means (UPGMA) and principle component analysis, and furthermore, molecular ecological network analysis indicated that some potential plant-beneficial microbial groups, e.g., Bacillus and Actinobacteria could act as network key taxa, thus reducing the chance of plant soil-borne pathogen invasion. In addition, we propose that a more complex soil ecology network may help suppress tobacco wilt, which was also consistent with highly diversity and composition with plant-beneficial microbial groups. This study provides new insights into our understanding the relationship between the soil microbiome and plant health.

  8. An Integrated Insight into the Relationship between Soil Microbial Community and Tobacco Bacterial Wilt Disease

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    Hongwu Yang

    2017-11-01

    Full Text Available The soil microbial communities play an important role in plant health, however, the relationship between the below-ground microbiome and above-ground plant health remains unclear. To reveal such a relationship, we analyzed soil microbial communities through sequencing of 16S rRNA gene amplicons from 15 different tobacco fields with different levels of wilt disease in the central south part of China. We found that plant health was related to the soil microbial diversity as plants may benefit from the diverse microbial communities. Also, those 15 fields were grouped into ‘healthy’ and ‘infected’ samples based upon soil microbial community composition analyses such as unweighted paired-group method with arithmetic means (UPGMA and principle component analysis, and furthermore, molecular ecological network analysis indicated that some potential plant-beneficial microbial groups, e.g., Bacillus and Actinobacteria could act as network key taxa, thus reducing the chance of plant soil-borne pathogen invasion. In addition, we propose that a more complex soil ecology network may help suppress tobacco wilt, which was also consistent with highly diversity and composition with plant-beneficial microbial groups. This study provides new insights into our understanding the relationship between the soil microbiome and plant health.

  9. Transgenic banana expressing Pflp gene confers enhanced resistance to Xanthomonas wilt disease.

    Science.gov (United States)

    Namukwaya, B; Tripathi, L; Tripathi, J N; Arinaitwe, G; Mukasa, S B; Tushemereirwe, W K

    2012-08-01

    Banana Xanthomonas wilt (BXW), caused by Xanthomonas campestris pv. musacearum, is one of the most important diseases of banana (Musa sp.) and currently considered as the biggest threat to banana production in Great Lakes region of East and Central Africa. The pathogen is highly contagious and its spread has endangered the livelihood of millions of farmers who rely on banana for food and income. The development of disease resistant banana cultivars remains a high priority since farmers are reluctant to employ labor-intensive disease control measures and there is no host plant resistance among banana cultivars. In this study, we demonstrate that BXW can be efficiently controlled using transgenic technology. Transgenic bananas expressing the plant ferredoxin-like protein (Pflp) gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of banana. These transgenic lines were characterized by molecular analysis. After challenge with X. campestris pv. musacearum transgenic lines showed high resistance. About 67% of transgenic lines evaluated were completely resistant to BXW. These transgenic lines did not show any disease symptoms after artificial inoculation of in vitro plants under laboratory conditions as well as potted plants in the screen-house, whereas non-transgenic control plants showed severe symptoms resulting in complete wilting. This study confirms that expression of the Pflp gene in banana results in enhanced resistance to BXW. This transgenic technology can provide a timely solution to the BXW pandemic.

  10. Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

    Science.gov (United States)

    Venkatesh; Krishna, V; Kumar, K Girish; Pradeepa, K; Kumar, S R Santosh; Kumar, R Shashi

    2013-07-01

    An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

  11. Current knowledge of coffee wilt disease, a major constraint to coffee production in Africa.

    Science.gov (United States)

    Rutherford, Mike A

    2006-06-01

    ABSTRACT Coffee is vital to the economy of East and Central Africa, providing a major source of foreign exchange earnings and, as a cash crop, supporting the livelihoods of millions involved in cultivation, processing, marketing, and export. Coffee wilt disease (CWD), attributed to Gibberella xylarioides (Fusarium xylarioides), has caused losses to coffee production in Africa since 1927 but has been largely contained through the use of host resistance and in some instances wide-scale sanitation practices. A reemergence of CWD on Coffea canephora (Robusta coffee) in Uganda, Democratic Republic of Congo, and Tanzania has already led to heavy losses and threatens future production in these countries and elsewhere in the region. The relevance of CWD is all the more pertinent given the impact of a considerable fall in world coffee prices over the last decade. Recent research has clarified the extent of the problem in the region and revealed a low level of diversity within the pathogen, suggesting that two genetically and biologically distinct forms are responsible for current problems. These findings and related research and development initiatives undertaken under the auspices of the Regional Coffee Wilt Programme are of fundamental importance in providing an urgently needed solution to this devastating disease.

  12. Bretziella, a new genus to accommodate the oak wilt fungus, Ceratocystis fagacearum (Microascales, Ascomycota

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    Z. Wilhelm de Beer

    2017-10-01

    Full Text Available Recent reclassification of the Ceratocystidaceae (Microascales based on multi-gene phylogenetic inference has shown that the oak wilt fungus Ceratocystis fagacearum does not reside in any of the four genera in which it has previously been treated. In this study, we resolve typification problems for the fungus, confirm the synonymy of Chalara quercina (the first name applied to the fungus and Endoconidiophora fagacearum (the name applied when the sexual state was discovered. Furthermore, the generic placement of the species was determined based on DNA sequences from authenticated isolates. The original specimens studied in both protologues and living isolates from the same host trees and geographical area were examined and shown to represent the same species. A lectotype was designated for Chalara quercina and Endoconidiophora fagacearum and an epitype linked to a living ex-epitype isolate was designated. Phylogenetic analyses confirmed that the species resides in a well-supported monophyletic lineage in the Ceratocystidaceae, distinct from all other genera in the family. The new genus Bretziella is described to accommodate the oak wilt fungus.

  13. Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

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    ABDJAD ASIH NAWANGSIH

    2011-06-01

    Full Text Available Biological control of bacterial wilt pathogen (Ralstonia solanacearum of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based on antagonistic effect on R. solanacearum or ability to suppress R. solanacearum population in dual culture assays obtained BC4 and BL10 isolates as promising biocontrol agents. At six weeks after transplanting, plants treated with BC4 isolate showed significantly lower disease incidence (33% than that of control (83%. Plants height was not significantly affected by endophytic bacterial treatments. Based on 16S rRNA sequence, BC4 isolate had 97% similarity with Staphylococcus epidermidis (accession number EU834240.1, while isolate BL10 had 98% similarity with Bacillus amyloliquefaciens strain JK-SD002 (accession number AB547229.1.

  14. Suppression of Fusarium wilt in tomato plants by rhizobacteria from the Bacillus genus

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    Renato Carrer Filho

    2015-09-01

    Full Text Available Vascular wilting in tomato plants constitutes an important group of diseases incited by soil inhabiting pathogens, especially Fusarium oxysporum f. sp. lycopersici, that causes significant production losses. The introgression of genes that express specific resistance is considered the main control method, however, due to the rapid emergence of races that suppress resistance, biocontrol has been presented as an option to be integrated with genetic control methods. This study aimed at evaluating the ability of rhizobacteria isolates, especially from the Bacillus genus, as biological control agents of Fusarium wilt in tomato plants. The laboratory assay was carried out to verify the ability of the isolates in acting as inhibitors of mycelial growth, besides detecting the genes involved in the expression of polypeptides with antimicrobial action. In the greenhouse, the assay comprised of microbiolized seeds and addition of a suspension of propagules of each rhizobacteria to the soil at the moment of transplanting the tomato seedlings. All the rhizobateria isolates showed variable control levels of the pathogen in vitro. The UFG-07 and UFG-10 isolates, with high similarity with Bacillus subtilis and Bacillus circulans, excelled in the disease suppression. PCR results detected target genes for expression of polypeptides, what reinforces the hypothesis of action of antimicrobial substances in biocontrol.

  15. Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt

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    Mahmoud H. El_Komy

    2015-03-01

    Full Text Available The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and β-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their anta- gonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents.

  16. Hairy root transgene expression analysis of a secretory peroxidase (PvPOX1) from common bean infected by Fusarium wilt.

    Science.gov (United States)

    Xue, Renfeng; Wu, Xingbo; Wang, Yingjie; Zhuang, Yan; Chen, Jian; Wu, Jing; Ge, Weide; Wang, Lanfen; Wang, Shumin; Blair, Matthew W

    2017-07-01

    Plant peroxidases (POXs) are one of the most important redox enzymes in the defense responses. However, the large number of different plant POX genes makes it necessary to carefully confirm the function of each paralogous POX gene in specific tissues and disease interactions. Fusarium wilt is a devastating disease of common bean caused by Fusarium oxysporum f. sp. phaseoli. In this study, we evaluated a peroxidase gene, PvPOX1, from a resistant common bean genotype, CAAS260205 and provided direct evidence for PvPOX1's role in resistance by transforming the resistant allele into a susceptible common bean genotype, BRB130, via hairy root transformation using Agrobacterium rhizogenes. Analysis of PvPOX1 gene over-expressing hairy roots showed it increased resistance to Fusarium wilt both in the roots and the rest of transgenic plants. Meanwhile, the PvPOX1 expressive level, the peroxidase activity and hydrogen peroxide (H2O2) accumulation were also enhanced in the interaction. The result showed that the PvPOX1 gene played an essential role in Fusarium wilt resistance through the occurrence of reactive oxygen species (ROS) induced hypersensitive response. Therefore, PvPOX1 expression was proven to be a valuable gene for further analysis which can strengthen host defense response against Fusarium wilt through a ROS activated resistance mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Sclerotinia wilt of Hop (Humulus lupulus) caused by Sclerotinia sclerotiorum in the Pacific Northwest U.S.

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    Sclerotinia sclerotiorum is a widespread, destructive pathogen with an exceptionally broad host range. During June 2011, wilted hop plants (Humulus lupulus cv. Nugget) were observed in a hop yard in Marion County, Oregon. Some affected plants had upward curled leaves with necrotic margins, whereas o...

  18. Molecular characterization of Ralstonia solanacearum strains from Ethiopia and tracing potential source of bacterial wilt disease outbreak in seed potatoes

    NARCIS (Netherlands)

    Abdurahman, A.; Griffin, D.; Elphinstone, J.; Struik, P.C.; Schulz, S.; Schulte-Geldermann, E.; Sharma, K.

    2017-01-01

    Bacterial wilt, caused by Ralstonia solanacearum, is emerging as a major threat to potato production in Ethiopia, reaching epidemic proportions in the Chencha district recently, with a prevalence of 97% of potato fields in 2015. The recent disease outbreak in the district coincided with a

  19. Detection and management of Xyleborus glabratus and other vectors of laurel wilt, a lethal disease affecting avocados in Florida

    Science.gov (United States)

    The redabay ambrosia beetle, Xyleborus glabratus, carries a phytopathogenic symbiont, Raffaelea lauricola, which causes laurel wilt, a lethal vascular disease of some Lauraceae species. Both X. glabratus and R. lauricola are natives of Asia that recently invaded much of the coastal plain of the sout...

  20. The role of weeds in the spread of Tomato spotted wilt virus by thrips tabaci (Thysanoptera: Thripidae) in tobacco crops

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Peters, D.; Katis, N.I.

    2007-01-01

    Oviposition of Thrips tabaci, larval development and their potential to acquire Tomato spotted wilt virus (TSWV) from infected Amaranthus retroflexus, Datura stramonium, Lactuca serriola, Solanum nigrum and Sonchus oleraceus plants and the ability of the adults to transmit this virus to these weeds

  1. The use of fluorescence microscopy to visualise homotypic interactions of tomato spotted wilt virus nucleocapsid protein in living cells

    NARCIS (Netherlands)

    Snippe, M.; Borst, J.W.; Goldbach, R.W.; Kormelink, R.J.M.

    2005-01-01

    Fluorescence resonance energy transfer (FRET) and fluorescence lifetime imaging microscopy (FLIM) were employed to study homotypic protein¿protein interactions in living cells. To this end, the nucleocapsid (N) protein of tomato spotted wilt virus (TSWV) was expressed as a fusion protein with either

  2. Isolations from the redbay ambrosia beetle, Xyleborus glabratus, confirm that the laurel wilt pathogen, Raffaelea lauricola, originated in Asia

    Science.gov (United States)

    Thomas C. Harrington; Hye Young Yun; Sheng-Shan Lu; Hideaki Goto; Dilzara N. Aghayeva; Stephen W. Fraedrich

    2011-01-01

    The laurel wilt pathogen Raffaelea lauricola was hypothesized to have been introduced to the southeastern USA in the mycangium of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia. To test this hypothesis adult X. glabratus were trapped in Taiwan and on Kyushu Island, Japan, in 2009, and dead beetles were sent to USA for isolation of fungal...

  3. Host preference of the vector beetle, host resistance, and expanding patterns of Japanese oak wilt in a stand

    Science.gov (United States)

    Kazuyoshi Futai; Hiroaki Kiku; Hong-ye Qi; Hagus Tarn; Yuko Takeuchi; Michimasa. Yamasaki

    2012-01-01

    Since the early 1980s, an epidemic forest disease, Japanese Oak Wilt (JOW), has been spreading from coastal areas along the Sea of Japan to the interior of Honshu island and has been devastating huge areas of forests by killing an enormous number of oak trees in urban fringe mountains, gardens, and parks. The disease is caused by a fungus, Raffaelea...

  4. BRS FC402: high-yielding common bean cultivar with carioca grain, resistance to anthracnose and fusarium wilt

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    Leonardo Cunha Melo

    2016-12-01

    Full Text Available BRS FC402 is a common bean cultivar of the carioca-grain group with commercial grain quality, suitable for cultivation in 21 Brazilian states. Cultivar has a normal cycle (85-94 days, high yield potential (4479 kg ha-1, 10.1% higher mean yield than the controls (2462 kg ha-1 and resistance to fusarium wilt and anthracnose.

  5. Chapter 11 - Progression of Laurel Wilt Disease in Georgia: 2009–11 (Project SC-EM-08-02)

    Science.gov (United States)

    R. Scott Cameron; Chip Bates; James Johnson

    2014-01-01

    Laurel wilt disease (LWD) is caused by the fungus Raffaelea lauricola and vectored by the redbay ambrosia beetle (RAB), Xyleborus glabratus (Fraedrich and others 2008). The pathogen and vector were apparently introduced from Asia through the Port of Savannah, and the disease has spread rapidly throughout the lower coastal plains forests in Georgia, killing nearly all...

  6. Quantification of Propagules of the Laurel Wilt Fungus and Other Mycangial Fungi from the Redbay Ambrosia Beetle, Xyleborus glabratus

    Science.gov (United States)

    T. C. Harrington; S. W. Fraedrich

    2010-01-01

    The laurel wilt pathogen, Raffaelea lauricola, is a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia and was believed to have brought R. lauricola with it to the southeastern United States. Individual X. glabratus beetles from six populations in South Carolina and Georgia were individually macerated in glass tissue grinders...

  7. Presence and prevalence of Raffaelea lauricola, cause of laurel wilt, in different species of ambrosia beetle in Florida USA

    Science.gov (United States)

    We summarize information on ambrosia beetle species that have been associated in Florida with Raffaelea lauricola, the primary symbiont of Xyleborus glabratus and cause of laurel wilt, a lethal disease of plants in the Lauraceae. Adult females of 14 species in Ambrosiodmus, Euwallacea, Premnobius, ...

  8. Responses of nitrogen metabolism and seed nutrition to drought stress in soybean genotypes differing in slow-wilting phenotype

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    Nacer eBellaloui

    2013-12-01

    Full Text Available Recent advances in soybean breeding have resulted in genotypes that express the slow-wilting phenotype (trait under drought stress conditions. The physiological mechanisms of this trait remain unknown due to the complexity of trait × environment interactions. The objective of this research was to investigate nitrogen metabolism and leaf and seed nutrients composition of the slow-wilting soybean genotypes under drought stress conditions. A repeated greenhouse experiment was conducted using check genotypes: NC-Roy (fast wilting, Boggs (intermediate in wilting; and NTCPR94-5157 and N04-9646 (slow-wilting, SLW genotypes. Plants were either well-watered or drought stressed. Results showed that under well-watered conditions, nitrogen fixation (NF, nitrogen assimilation (NA, and leaf and seed composition differed between genotypes. Under drought stress, NF and NA were higher in NTCPR94-5157 and N04-9646 than in NC-Roy and Boggs. Under severe water stress, however, NA was low in all genotypes. Leaf water potential was significantly lower in checks (-2.00 MPa than in the SLW genotypes (-1.68 MPa. Leaf and seed concentrations of K, P, Ca, Cu, Na, B were higher in SLW genotypes than in the checks under drought stress conditions. Seed protein, oleic acid, and sugars were higher in SLW genotypes, and oil, linoleic and linolenic acids were lower in SLW genotypes. This research demonstrated that K, P, Ca, Cu, Na, and B may be involved in SLW trait by maintaining homeostasis and osmotic regulation. Maintaining higher leaf water potential in NTCPR94-5157 and N04-9646 under drought stress could be a possible water conservation mechanism to maintain leaf turgor pressure. The increase in osmoregulators such as minerals, raffinose and stachyose, and oleic acid could be beneficial for soybean breeders in selecting for drought stress tolerance.

  9. Combination of endophytic Bacillus and Beauveria for the management of Fusarium wilt and fruit borer in tomato.

    Science.gov (United States)

    Prabhukarthikeyan, Rathinam; Saravanakumar, Duraisamy; Raguchander, Thiruvengadam

    2014-11-01

    Most of the approaches for biocontrol of pests and diseases have used a single biocontrol agent as antagonist to a single pest or pathogen. This accounts for the inconsistency in the performance of biocontrol agents. The development of a bioformulation possessing a mixture of bioagents could be a viable option for the management of major pests and diseases in crop plants. A bioformulation containing a mixture of Beauveria bassiana (B2) and Bacillus subtilis (EPC8) was tested against Fusarium wilt and fruit borer in tomato under glasshouse and field conditions. The bioformulation with B2 and EPC8 isolates effectively reduced the incidence of Fusarium wilt (Fusarium oxysporum f. sp. lycopersici) and fruit borer (Helicoverpa armigera) under glasshouse and field conditions compared with the individual application of B2 and EPC8 isolates and control treatments. In vitro studies showed a higher larval mortality of H. armigera when fed with B2 + EPC8-treated leaves. Further, plants treated with the B2 + EPC8 combination showed a greater accumulation of defence enzymes such as lipoxygenase, peroxidase and polyphenol oxidase against wilt pathogen and fruit borer pest than the other treatments. Moreover, a significant increase in growth parameters and yield was observed in tomato plants treated with B2 + EPC8 compared with the individual bioformulations and untreated control. The combined application of Beauveria and Bacillus isolates B2 and EPC8 effectively reduced wilt disease and fruit borer attack in tomato plants. Results show the possibility of synchronous management of tomato fruit borer pest and wilt disease in a sustainable manner. © 2013 Society of Chemical Industry.

  10. The ER-Membrane Transport System Is Critical for Intercellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus

    National Research Council Canada - National Science Library

    Feng, Zhike; Xue, Fan; Xu, Min; Chen, Xiaojiao; Zhao, Wenyang; Garcia-Murria, Maria J; Mingarro, Ismael; Liu, Yong; Huang, Ying; Jiang, Lei; Zhu, Min; Tao, Xiaorong

    2016-01-01

    ...s. In the present study, the contribution of the plant ER membrane transport system to the intercellular trafficking of the NSm movement protein and Tomato spotted wilt tospovirus (TSWV) is investigated...

  11. Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts

    National Research Council Canada - National Science Library

    Zhang, Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

    2016-01-01

    Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China...

  12. Evolutionary analysis of tomato Sw-5 resistance-breaking isolates of Tomato spotted wilt virus.

    Science.gov (United States)

    López, Carmelo; Aramburu, José; Galipienso, Luis; Soler, Salvador; Nuez, Fernando; Rubio, Luis

    2011-01-01

    Tomato spotted wilt virus (TSWV) causes severe economic losses in many crops worldwide and often overcomes resistant cultivars used for disease control. Comparison of nucleotide and amino acid sequences suggested that tomato resistance conferred by the gene Sw-5 can be overcome by the amino acid substitution C to Y at position 118 (C118Y) or T120N in the TSWV movement protein, NSm. Phylogenetic analysis revealed that substitution C118Y has occurred independently three times in the studied isolates by convergent evolution, whereas the substitution T120N was a unique event. Analysis of rates of non-synonymous and synonymous changes at individual codons showed that substitution C118Y was positively selected.

  13. Selection of tomato plants resistant to a local Polish isolate of tomato spotted wilt virus (TSWV).

    Science.gov (United States)

    Czech, Andrzej S; Szklarczyk, Marek; Gajewski, Zbigniew; Zukowska, Ewa; Michalik, Barbara; Kobyłko, Tadeusz; Strzałka, Kazimierz

    2003-01-01

    We found that the Sw-5 gene confers resistance to one of the Polish isolates of tomato spotted wilt virus (TSWV). A series of tomato breeding accessions was analysed along with standards of resistance and susceptibility to TSWV. The presence of the Sw-5 gene was determined using the available PCR marker. Subsequently plants from these accessions were grown in the presence of the TSWV isolate from Poland. Some of them developed severe symptoms of the TSWV disease. Expression of the virus proteins was also assayed in tissues of the investigated plants. We found general agreement between either lack or presence of the disease symptoms, virus proteins and resistance gene. Some observed discrepancies of these data are also discussed. Our results indicate that marker-assisted selection can be used for breeding of the TSWV-resistant tomato in Poland.

  14. Cape Saint Paul Wilt Disease of coconut in Ghana: surveillance and management of disease spread

    Directory of Open Access Journals (Sweden)

    Nkansah-Poku Joe

    2009-03-01

    Full Text Available The Cape Saint Paul Wilt Disease (CSPWD, a lethal-yellowing type disease of coconut has been in Ghana since 1932. Aerial and/or ground surveys were undertaken to assess the current status of the disease spread. The survey showed that the spread of the disease for the past 5 years has mainly been the expansion of existing foci. However, new outbreaks were identified at Glidzi in the Volta, Bawjiase and Efutu Breman in Central regions. After the resurgence in the Volta region in 1995, the Woe-Tegbi-Dzelukope corridor has remained endemic, but less aggressive. Pockets of healthy groves remain along all the coastline and inland of known disease zones. Eradication of diseased palms at Ampain focus lying just about 60 km to the Ivorian border, and disease situations on new replanting with MYD × VTT hybrid are discussed.

  15. Three decades of managing Tomato spotted wilt virus in peanut in southeastern United States.

    Science.gov (United States)

    Srinivasan, R; Abney, M R; Culbreath, A K; Kemerait, R C; Tubbs, R S; Monfort, W S; Pappu, H R

    2017-09-15

    Southeastern states namely Georgia, Florida, and Alabama produce two-thirds of the peanuts in the United States. Thrips-transmitted Tomato spotted wilt virus (TSWV), which causes spotted wilt disease, has been a major impediment to peanut production for the past three decades. The cultivars grown in the 1980s were extremely susceptible to TSWV. Early yield losses extended to tens of millions of dollars each year (up to 100% loss in many fields). This situation led to the creation of an interdisciplinary team known as "SWAT: Spotted Wilt Action Team". Initial efforts focused on risk mitigation using a combination of chemical and cultural management practices along with a strong investment in breeding programs. Beginning in the mid 1990s, cultivars with field resistance were developed and integrated with cultural and chemical management options. A Risk Mitigation Index (Peanut Rx) was made available to growers to assess risks, and provide options for mitigating risks such as planting field resistant cultivars with in-furrow insecticides, planting after peak thrips incidence, planting in twin rows, and increasing seeding rates. These efforts helped curtail losses due to spotted wilt. The Peanut Rx continues to be refined every year based on new research findings. Breeding efforts, predominantly in Georgia and Florida, continue to develop cultivars with incremental field resistance. The present-day cultivars (third-generation TSWV-resistant cultivars released after 2010) possess substantially greater field resistance than second-generation (cultivars released from 2000 to 2010) and first-generation (cultivars released from 1994 to 2000) TSWV resistant cultivars. Despite increased field resistance, these cultivars are not immune to TSWV and succumb under high thrips and TSWV pressure. Therefore, field resistant cultivars cannot serve as a 'stand-alone' option and have to be integrated with other management options. The mechanism of resistance is also unknown in field

  16. Screening of antagonistic bacteria for biological control of nursery wilt of black pepper (Piper nigrum).

    Science.gov (United States)

    Anith, K N; Radhakrishnan, N V; Manomohandas, T P

    2003-01-01

    Bacterial antagonists of Phytophthora capsici were isolated from underground shoot portions of rooted cuttings of black pepper. Initially isolates were screened by dual culture on potato dextrose agar and carrot agar. Further, a screening was done on black pepper shoots for supression of lesion caused by the pathogen. Most of the antagonists showed varying levels of antagonism in the dual culture and the shoot assay. Isolate PN-026, showing the highest suppression of lesion development in the shoot assay was found to be the most efficient antagonist in reducing Phytophthora capsici induced nursery wilt of black pepper. This screening involving the host, pathogen, and the antagonist, performed on black pepper shoot (the planting material for this vegetatively propagated crop), could be used as a rapid and reliable method for the isolation of efficient bacterial antagonists of P. capsici.

  17. Increasing Soil Suppressivity to Fusarium Wilt Of Banana Through Banana Intercropping with Allium spp.

    Directory of Open Access Journals (Sweden)

    Arif Wibowo

    2015-07-01

    Full Text Available Fusarium wilt, caused by Fusarium oxysporum f.sp. cubense (Foc, is one of the most destructive diseases of banana and has spread in many plantation areas in Indonesia. Until today, the effective ways to control banana fusarium wilt disease have not yet been found. Some studies indicated thatAllium spp. could be used to suppress plant diseases caused by Fusarium. Allium spp. are important horticultural crops which are generally cultivated in some areas in Indonesia. This research was conducted to determine the effect of several species ofAllium spp. intercropped with banana to improve soil suppressiveness against banana fusarium wilt disease. The results showed that up to 12 months after planting, from 3 species ofAllium spp. (A. tuberosum/ Chinese leek, A. fistulosum/ bunching onion, and A. cepa var. aggregatum/ shallot intercropped with banana Ambon Kuning (AAA cultivar, Chinese leek and shallot were able to suppress the incidence of fusarium wilt disease of banana by 46 and 33% respectively. Soil analysis on the rhizosphere of banana intercropped with Chinese leek and shallot had lower population of total Fusarium compared to the other treatments. Analysis of fluorescein diacetate (3’.6’-diacetylfluoerescein or FDA also showed that total microbial activity in the rhizosphere of banana intercropped withAllium spp. was also lower compared to control treatment (without intercropping. The observation of the effect ofAllium spp. extracts on Foc showed that Allium spp. extracts were able to suppress the development of the colony and spore germination of Foc in vitro.   INTISARI Layu Fusarium, yang disebabkan oleh Fusarium oxysporum f.sp. cubense (Foc, merupakan salah satu penyakit tanaman pisang yang paling merusak dan telah tersebar di berbagai daerah di Indonesia. Sampai saat ini cara yang efektif untuk mengendalikan penyakit layu fusarium pisang belum ditemukan. Beberapa penelitian menunjukkan bahwa Allium spp. dapat dipergunakan

  18. Biochemical Defenses Induced by Mycorrhizae Fungi Glomus Mosseae in Controlling Strawberry Fusarium Wilt.

    Science.gov (United States)

    Yanan, Wang; Xusheng, Zhao; Baozhong, Yin; Wenchao, Zhen; Jintang, Guo

    2015-01-01

    The effect of VAM on reducing wilt caused by Fusarium oxysporum Schlecht. f.sp. fragariae Winks et Williams (FO) infection in strawberry and the possible mechanisms involved were investigated. Two key substance involved in disease defenses, lignin and hydroxyproline-rich glycoprotein were induced and formed in the cell wall of strawberry root, and the peak content of lignin and hydroxyproline-rich glycoprotein occurred on the 25(th) day (149.52mg/g) and on the 15(th) day (10.08 mg/g). The activity of protective enzymes SOD, POD and CAT inoculation with VAM significantly increased when compared with the control under both CK (natural growth) and inoculated with FO. The conductivity of VAM plus FO treatment was higher than the CK treatment, but significantly was lower than the FO treatment.

  19. The Microbiome of Endophytic, Wood Colonizing Bacteria from Pine Trees as Affected by Pine Wilt Disease

    DEFF Research Database (Denmark)

    Proença, Diogo Neves; Francisco, Romeu; Kublik, Susanne

    2017-01-01

    of the invasion with the pathogen were comparable. Interestingly diversity of wood endophytic bacteria increased with the severity of the diseases, with highest diversity levels observed in in the most affected trees. Our results suggest that in the first stages of the disease, the defence mechanisms of plants......Pine wilt disease (PWD) is a devastating forest disease present worldwide. In this study we analyzed the effects of the invasion of the pinewood nematode Bursaphelenchus xylophilus, the major pathogen causing PWD, on the endophytic microbiome of adult P. pinaster trees. Wood samples from trees...... with different degrees of PWD disease were collected at two sites (A and M) in Portugal. Endophytic bacteria were characterized based on directly extracted DNA by fingerprinting and barcoding using the 16S rRNA gene as marker. Furthermore, cultivation-based approaches were used to obtain isolates of the major...

  20. The Role of the Beetle Hypocryphalus mangiferae (Coleoptera: Curculionidae) in the Spatiotemporal Dynamics of Mango Wilt.

    Science.gov (United States)

    Galdino, Tarcísio Visintin da Silva; Ferreira, Dalton de Oliveira; Santana Júnior, Paulo Antônio; Arcanjo, Lucas de Paulo; Queiroz, Elenir Aparecida; Sarmento, Renato Almeida; Picanço, Marcelo Coutinho

    2017-06-01

    The knowledge of the spatiotemporal dynamics of pathogens and their vectors is an important step in determining the pathogen dispersion pattern and the role of vectors in disease dynamics. However, in the case of mango wilt little is known about its spatiotemporal dynamics and the relationship of its vector [the beetle Hypocryphalus mangiferae (Stebbing 1914)] to these dynamics. The aim of this work was to determine the spatial-seasonal dynamic of H. mangiferae attacks and mango wilt in mango orchards and to verify the importance of H. mangiferae in the spatiotemporal dynamics of the disease. Two mango orchards were monitored during a period of 3 yr. The plants in these orchards were georeferenced and inspected monthly to quantify the number of plants attacked by beetles and the fungus. In these orchards, the percentage of mango trees attacked by beetles was always higher than the percentage infected by the fungus. The colonization of mango trees by beetles and the fungus occurred by colonization of trees both distant and proximal to previously attacked trees. The new plants attacked by the fungus emerged in places where the beetles had previously begun their attack. This phenomenon led to a large overlap in sites of beetle and fungal occurrence, indicating that establishment by the beetle was followed by establishment by the fungus. This information can be used by farmers to predict disease infection, and to control bark beetle infestation in mango orchards. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith Yabuuchi

    Directory of Open Access Journals (Sweden)

    Naseerud Din

    2016-08-01

    Full Text Available Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue, Calotropis procera (sodom apple, Melia azedarach (white cedar, Allium sativum (garlic, Adhatoda vasica (malabar nut, Tagetes patula (marigold and Nerium oleander (oleander were assessed for their anti-microbial activity, both in-vitro (10% w/v and in-vivo (10, 20, 30, and 40 g/kg of potted soil against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato.

  2. Apoptosis-related genes confer resistance to Fusarium wilt in transgenic 'Lady Finger' bananas.

    Science.gov (United States)

    Paul, Jean-Yves; Becker, Douglas K; Dickman, Martin B; Harding, Robert M; Khanna, Harjeet K; Dale, James L

    2011-12-01

    Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most devastating diseases of banana (Musa spp.). Apart from resistant cultivars, there are no effective control measures for the disease. We investigated whether the transgenic expression of apoptosis-inhibition-related genes in banana could be used to confer disease resistance. Embryogenic cell suspensions of the banana cultivar, 'Lady Finger', were stably transformed with animal genes that negatively regulate apoptosis, namely Bcl-xL, Ced-9 and Bcl-2 3' UTR, and independently transformed plant lines were regenerated for testing. Following a 12-week exposure to Foc race 1 in small-plant glasshouse bioassays, seven transgenic lines (2 × Bcl-xL, 3 × Ced-9 and 2 × Bcl-2 3' UTR) showed significantly less internal and external disease symptoms than the wild-type susceptible 'Lady Finger' banana plants used as positive controls. Of these, one Bcl-2 3' UTR line showed resistance that was equivalent to that of wild-type Cavendish bananas that were included as resistant negative controls. Further, the resistance of this line continued for 23-week postinoculation at which time the experiment was terminated. Using TUNEL assays, Foc race 1 was shown to induce apoptosis-like features in the roots of wild-type 'Lady Finger' plants consistent with a necrotrophic phase in the life cycle of this pathogen. This was further supported by the observed reduction in these effects in the roots of the resistant Bcl-2 3' UTR-transgenic line. This is the first report on the generation of transgenic banana plants with resistance to Fusarium wilt. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  3. Identification of a Potential ISR Determinant from Pseudomonas aeruginosa PM12 against Fusarium Wilt in Tomato

    Science.gov (United States)

    Fatima, Sabin; Anjum, Tehmina

    2017-01-01

    Biocontrol of plant diseases through induction of systemic resistance is an environmental friendly substitute to chemicals in crop protection measures. Different biotic and abiotic elicitors can trigger the plant for induced resistance. Present study was designed to explore the potential of Pseudomonas aeruginosa PM12 in inducing systemic resistance in tomato against Fusarium wilt. Initially the bioactive compound, responsible for ISR, was separated and identified from extracellular filtrate of P. aeruginosa PM12. After that purification and characterization of the bacterial crude extracts was carried out through a series of organic solvents. The fractions exhibiting ISR activity were further divided into sub-fractions through column chromatography. Sub fraction showing maximum ISR activity was subjected to Gas chromatography/mass spectrometry for the identification of compounds. Analytical result showed three compounds in the ISR active sub-fraction viz: 3-hydroxy-5-methoxy benzene methanol (HMB), eugenol and tyrosine. Subsequent bioassays proved that HMB is the potential ISR determinant that significantly ameliorated Fusarium wilt of tomato when applied as soil drench method at the rate of 10 mM. In the next step of this study, GC-MS analysis was performed to detect changes induced in primary and secondary metabolites of tomato plants by the ISR determinant. Plants were treated with HMB and Fusarium oxysporum in different combinations showing intensive re- modulations in defense related pathways. This work concludes that HMB is the potential elicitor involved in dynamic reprogramming of plant pathways which functionally contributes in defense responses. Furthermore the use of biocontrol agents as natural enemies of soil borne pathogens besides enhancing production potential of crop can provide a complementary tactic for sustainable integrated pest management. PMID:28620396

  4. Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi

    Energy Technology Data Exchange (ETDEWEB)

    Din, N.; Ahmad, M.; Siddique, M.; Ali, A.; Naz, I.; Ullah, N.; Ahmad, F.

    2016-11-01

    Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue), Calotropis procera (sodom apple), Melia azedarach (white cedar), Allium sativum (garlic), Adhatoda vasica (malabar nut), Tagetes patula (marigold) and Nerium oleander (oleander) were assessed for their anti-microbial activity, both in-vitro (10% w/v) and in-vivo (10, 20, 30, and 40 g/kg of potted soil) against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering) of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil) of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil) could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato. (Author)

  5. Diverse microbial communities in non-aerated compost teas suppress bacterial wilt.

    Science.gov (United States)

    Mengesha, W K; Powell, S M; Evans, K J; Barry, K M

    2017-03-01

    Non-aerated compost teas (NCTs) are water extracts of composted organic materials and are used to suppress soil borne and foliar disease in many pathosystems. Greenhouse trials were used to test the effectiveness of NCTs to suppress potato bacterial wilt caused by Ralstonia solanacearum on plants grown in soils inoculated with a virulent isolate of the pathogen (biovar II). NCTs prepared from matured compost sources: agricultural waste (AWCT), vermicompost (VCT) and solid municipal waste (SMWCT) were evaluated at three initial application times (7 days before inoculation, at time of inoculation and 7 days after inoculation) prior to weekly applications, in a randomized complete-block design. AWCT applied initially at the time of inoculation resulted in the greatest disease suppression, with the disease severity index 2.5-fold less than the non-treated plants and the "area under the disease progress curve" (AUDPC) 3.2-fold less. VCT and SMWCT were less suppressive than AWCT regardless of initial application time. Next generation sequencing of the v4 region of 16S rRNA gene and the internal transcribed spacer region (ITS1) revealed that diversity and composition of the bacterial and fungal communities across the NCTs varied significantly. Dominant bacterial phyla such as Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, Verrucomicrobia, Chloroflexi, Planctomycetes, Acidobacteria, and a fungal phylum Ascomycota were detected in all NCTs. AWCT had optimum physico-chemical measurements with higher bacterial Shannon diversity indices (H) and fungal richness (S) than the other treatments. We conclude that bacterial wilt of potatoes grown in controlled conditions can be suppressed by a non-aerated compost tea with a high microbial diversity when applied at planting and weekly thereafter.

  6. Evaluation of Streptomyces spp. against Fusarium oxysporum f. sp. ciceris for the management of chickpea wilt

    Directory of Open Access Journals (Sweden)

    Amini Jahanshir

    2016-07-01

    Full Text Available In this study, about 112 isolates of Streptomyces were isolated from chickpea rhizospheric soils. Among the isolated strains, five showed strong inhibitory effects against chickpea Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris in vitro using plate assay and selected for further studies. The selected strains were identified as Streptomyces spp. based on morphological and biochemical characterization as well as 16S rDNA sequences analysis. Our results assigned them to strains related to genus of Streptomyces. In vitro, antagonistic effects of Streptomyces strains against the disease were evaluated through the dual-culture method, volatile and non-volatile metabolites, siderophore, protease and chitinase production. All bacterial strains inhibited mycelial growth of the pathogen ranging from 26 to 44.2% in dual culture assay. The non-volatile extract of five of the Streptomyces strains inhibited more than 50% growth of the pathogen, whereas volatile compounds were less effective on mycelial growth inhibition (20.2 to 33.4%. The ability of the biocontrol agents to produce siderophore and protease were varied, whereas, production of chitinase was detected for all strains. Results of the greenhouse assay indicated that all biocontrol agents reduced disease severity (ranging from 38.7 to 54.8%. Accordingly, strain KS62 showed higher control efficacy (54.8%. In addition, the biomass of chickpea plants (plant height and dry weight significantly increased in plants treated with Streptomyces strains compared to non-bacterized control. The results of this study showed that it may be possible to manage chickpea Fusarium wilt disease effectively by using Streptomyces species, as biocontrol agents. Therefore, evaluating their efficiency under field conditions is needed.

  7. Identification of a Potential ISR Determinant from Pseudomonas aeruginosa PM12 against Fusarium Wilt in Tomato

    Directory of Open Access Journals (Sweden)

    Sabin Fatima

    2017-05-01

    Full Text Available Biocontrol of plant diseases through induction of systemic resistance is an environmental friendly substitute to chemicals in crop protection measures. Different biotic and abiotic elicitors can trigger the plant for induced resistance. Present study was designed to explore the potential of Pseudomonas aeruginosa PM12 in inducing systemic resistance in tomato against Fusarium wilt. Initially the bioactive compound, responsible for ISR, was separated and identified from extracellular filtrate of P. aeruginosa PM12. After that purification and characterization of the bacterial crude extracts was carried out through a series of organic solvents. The fractions exhibiting ISR activity were further divided into sub-fractions through column chromatography. Sub fraction showing maximum ISR activity was subjected to Gas chromatography/mass spectrometry for the identification of compounds. Analytical result showed three compounds in the ISR active sub-fraction viz: 3-hydroxy-5-methoxy benzene methanol (HMB, eugenol and tyrosine. Subsequent bioassays proved that HMB is the potential ISR determinant that significantly ameliorated Fusarium wilt of tomato when applied as soil drench method at the rate of 10 mM. In the next step of this study, GC-MS analysis was performed to detect changes induced in primary and secondary metabolites of tomato plants by the ISR determinant. Plants were treated with HMB and Fusarium oxysporum in different combinations showing intensive re- modulations in defense related pathways. This work concludes that HMB is the potential elicitor involved in dynamic reprogramming of plant pathways which functionally contributes in defense responses. Furthermore the use of biocontrol agents as natural enemies of soil borne pathogens besides enhancing production potential of crop can provide a complementary tactic for sustainable integrated pest management.

  8. Expression of rice thaumatin-like protein gene in transgenic banana plants enhances resistance to fusarium wilt.

    Science.gov (United States)

    Mahdavi, F; Sariah, M; Maziah, M

    2012-02-01

    The possibility of controlling Fusarium wilt--caused by Fusarium oxysporum sp. cubensec (race 4)--was investigated by genetic engineering of banana plants for constitutive expression of rice thaumatin-like protein (tlp) gene. Transgene was introduced to cauliflower-like bodies' cluster, induced from meristemic parts of male inflorescences, using particle bombardment with plasmid carrying a rice tlp gene driving by the CaMV 35S promoter. Hygromycin B was used as the selection reagent. The presence and integration of rice tlp gene in genomic DNA confirmed by PCR and Southern blot analyses. RT-PCR revealed the expression of transgene in leaf and root tissues in transformants. Bioassay of transgenic banana plants challenged with Fusarium wilt pathogen showed that expression of TLP enhanced resistance to F. oxysporum sp. cubensec (race 4) compared to control plants.

  9. Transcriptional responses of Italian ryegrass during interaction with Xanthomonas translucens pv. graminis reveal novel candidate genes for bacterial wilt resistance

    DEFF Research Database (Denmark)

    Wichmann, Fabienne; Asp, Torben; Widmer, Franko

    2011-01-01

    Xanthomonas translucens pv. graminis (Xtg) causes bacterial wilt, a severe disease of forage grasses such as Italian ryegrass (Lolium multiflorum Lam.). In order to gain a more detailed understanding of the genetic control of resistance mechanisms and to provide prerequisites for marker assisted...... selection, the partial transcriptomes of two Italian ryegrass genotypes, one resistant and one susceptible to bacterial wilt were compared at four time points after Xtg infection. A cDNA microarray developed from a perennial ryegrass (Lolium perenne) expressed sequence tag set consisting of 9,990 unique...... genes was used for transcriptome analysis in Italian ryegrass. An average of 4,487 (45%) of the perennial ryegrass sequences spotted on the cDNA microarray were detected by cross-hybridisation to Italian ryegrass. Transcriptome analyses of the resistant versus the susceptible genotype revealed...

  10. Impact of Bacillus amyloliquefaciens S13-3 on control of bacterial wilt and powdery mildew in tomato.

    Science.gov (United States)

    Yamamoto, Shoko; Shiraishi, Soma; Kawagoe, Yumi; Mochizuki, Mai; Suzuki, Shunji

    2015-05-01

    Biological control is a non-hazardous technique to control plant diseases. Researchers have explored microorganisms that show high plant-disease control efficiency for use as biological control agents. A single soil application of Bacillus amyloliquefaciens strain S13-3 suppressed tomato bacterial wilt caused by Ralstonia solanacearum, a soilborne bacterial pathogen, through production of antibiotics augmented possibly by induction of systemic acquired resistance. Soil application also controlled tomato powdery mildew disease through induction of systemic acquired resistance. S13-3 showing bifunctional activity with a single application to soil may be an innovative biological control agent against bacterial wilt and powdery mildew in tomato. © 2014 Society of Chemical Industry.

  11. Inhibitory Effect of Algal Extracts on Mycelial Growth of the Tomato-Wilt Pathogen, Fusarium oxysporum f. sp. lycopersici

    Science.gov (United States)

    Kim, Jiyoung

    2008-01-01

    The present study was undertaken to explore the inhibitory effect of cyanobacterial extracts of Nostoc commune FA-103 against the tomato-wilt pathogen, Fusarium oxysporum f. sp. lycopersici. In an optimal medium, cell growth, antifungal activity, and antifungal compound production could be increased 2.7-fold, 4.1-fold, and 13.4-fold, respectively. A crude algal extract had a similar effect as mancozeb at the recommended dose, both in laboratory and pot tests. In vitro and in vivo fungal growth, spore sporulation and fungal infection of wilt pathogen in tomato seeds were significantly inhibited by cyanobacterial extracts. Nostoc commune FA-103 extracts have potential for the suppression of Fusarium oxysporum f. sp. lycopersici. PMID:23997634

  12. The influence of different concentrations of bio-organic fertilizer on cucumber Fusarium wilt and soil microflora alterations.

    Science.gov (United States)

    Huang, Nan; Wang, Weiwei; Yao, Yanlai; Zhu, Fengxiang; Wang, Weiping; Chang, Xiaojuan

    2017-01-01

    Fusarium wilt is one of the main diseases of cucumber, and bio-organic fertilizer has been used to control Fusarium wilt. In this study, a pot experiment was conducted to evaluate the effects of bio-organic fertilizer applied at four levels on the suppression of Fusarium wilt disease in cucumber, the soil physico-chemical properties and the microbial communities. In comparison with the control (CK), low concentrations of bio-organic fertilizer (BIO2.5 and BIO5) did not effectively reduce the disease incidence and had little effect on soil microorganisms. High concentrations of bio-organic fertilizer (BIO10 and BIO20) significantly reduced the disease incidence by 33.3%-66.7% and the production was significantly improved by 83.8%-100.3%. The soil population of F. oxysporum f. sp. cucumerinum was significantly lower in bio-organic fertilizer treatments, especially in BIO10 and BIO20. The microorganism activity increased with the bio-organic fertilizer concentration. High-throughput sequencing demonstrated that, at the order level, Sphingomonadales, Bacillales, Solibacterales and Xylariales were significantly abundant in BIO10 and BIO20 soils. At the genus level, the abundance and composition of bacterial and fungal communities in BIO10 and BIO20 were similar, illustrating that high concentrations of bio-organic fertilizer activated diverse groups of microorganisms. Redundancy analysis (RDA) showed that Xanthomonadales, Sphingomonadales, Bacillales, Orbiliales, Sordariales, and Mucorales occurred predominantly in the BIO10 and BIO20. These microorganisms were related to the organic matter, available potassium and available phosphorus contents. In conclusion, a high concentration of bio-organic fertilizer application suppressed the Fusarium wilt disease and increased cucumber production after continuous cropping might through improving soil chemical condition and manipulating the composition of soil microbial community.

  13. Assessment of recent outbreaks of Dickeya sp (syn. Erwinia chrysanthemi) slow wilt in potato crops in Israel

    OpenAIRE

    Tsror, L.; Erlich, O.; Lebiush, S.; Hazanovsky, M.; Zig, U.; Slawiak, M.; Grabe, G.; Wolf, van der, J.M.; Haar, van de, J.J.

    2009-01-01

    Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004-2006, with disease incidence of 2-30% ( 10% in average). In addition to typical wilting symptoms on the foliage, in cases of severe infection, progeny tubers were rotten in the soil. Six strains were characterised by biochemical, serological and PC...

  14. Characterization of a New Tomato Spotted Wilt Virus Isolates Found in Hippeastrum hybridum (Hort.) Plants in Poland

    OpenAIRE

    Berniak Hanna

    2016-01-01

    Two Tomato spotted wilt virus (TSWV) isolates H1 and H2 found in Hippeastrum hybridum plants were characterized based on biological, serological, and molecular properties. Virus isolates showed differences in symptom expression – H1 isolate displayed severe necrotic spots and patterns, whereas mild mosaic symptoms were observed on H2-infected H. hybridum plants. Both TSWV isolates showed comparable reactivity with TSWV-specific antibodies and they induced similar symptoms on herbaceous indica...

  15. Transgenic banana plants expressing Xanthomonas wilt resistance genes revealed a stable non-target bacterial colonization structure

    OpenAIRE

    Nimusiima, Jean; K?berl, Martina; Tumuhairwe, John Baptist; Kubiriba, Jerome; Staver, Charles; Berg, Gabriele

    2015-01-01

    Africa is among the continents where the battle over genetically modified crops is currently being played out. The impact of GM in Africa could potentially be very positive. In Uganda, researchers have developed transgenic banana lines resistant to banana Xanthomonas wilt. The transgenic lines expressing hrap and pflp can provide a timely solution to the pandemic. However, the impact of the transgenes expression on non-target microorganisms has not yet been investigated. To study this effect,...

  16. Fusarium wilt incidence and common bean yield according to the preceding crop and the soil tillage system.

    OpenAIRE

    Eliane Divina de Toledo‑Souza; Pedro Marques da Silveira; Adalberto Corrêa Café‑Filho; Murillo Lobo Junior

    2012-01-01

    The objective of this work was to evaluate the effects of preceding crops and tillage systems on the incidence of Fusarium wilt (Fusarium oxysporum f. sp. phaseoli) and common bean (Phaseolus vulgaris) yield. The cultivar BRS Valente was cultivated under center‑pivot irrigation in the winter seasons of 2003, 2004 and 2005, after several preceding crops established in the summer seasons. Preceding crops included the legumes Cajanus cajan (pigeon pea), Stylosanthes guianensis, and Crotala...

  17. Significant relationship between soil bacterial community structure and incidence of bacterial wilt disease under continuous cropping system.

    Science.gov (United States)

    She, Siyuan; Niu, Jiaojiao; Zhang, Chao; Xiao, Yunhua; Chen, Wu; Dai, Linjian; Liu, Xueduan; Yin, Huaqun

    2017-03-01

    Soil bacteria are very important in biogeochemical cycles and play significant role in soil-borne disease suppression. Although continuous cropping is responsible for soil-borne disease enrichment, its effect on tobacco plant health and how soil bacterial communities change are yet to be elucidated. In this study, soil bacterial communities across tobacco continuous cropping time-series fields were investigated through high-throughput sequencing of 16S ribosomal RNA genes. The results showed that long-term continuous cropping could significantly alter soil microbial communities. Bacterial diversity indices and evenness indices decreased over the monoculture span and obvious variations for community structures across the three time-scale tobacco fields were detected. Compared with the first year, the abundances of Arthrobacter and Lysobacter showed a significant decrease. Besides, the abundance of the pathogen Ralstonia spp. accumulated over the monoculture span and was significantly correlated with tobacco bacterial wilt disease rate. Moreover, Pearson's correlation demonstrated that the abundance of Arthrobacter and Lysobacter, which are considered to be beneficial bacteria had significant negative correlation with tobacco bacterial wilt disease. Therefore, after long-term continuous cropping, tobacco bacterial wilt disease could be ascribed to the alteration of the composition as well as the structure of the soil microbial community.

  18. Wilting of date palm branches by Fusarium oxysporum in south of Iran and its control managements with soil solarization method.

    Science.gov (United States)

    Saremi, H; Okhovvat, S M; Ashrafi, S J

    2007-01-01

    Wilting of some branches in nurseries and orchards of date palm were studied in south of Iran including Ahvaz and Abadan cities in 2005-2006 years. Different infected plants were visited and samples showing symptoms including wilting or death of branches collected from various areas and transferred to laboratory. Samples were cultured in common media (PDA) and different fungi were studied and identified. The most frequently isolated pathogen was Fusarium oxysporum which caused wilting of some branches of date palm seedling or trees in studied areas. Results showed that the disease caused main losses where date palm cuttings were cultured in infected soils, previously cropped to susceptible plants. Since chemical control was not managed the disease, soil disinfestations by soil solarization method was carried in Ahvaz as the warmer climate in studied areas to control the pathogen. Application of this method reduced population density of the pathogen from 1800 CFU -g/soil to 600 after 5 week. This method was simple, effective, non negative side and economic which can be used in nearly warm areas.

  19. Antibacterial activity of tannins isolated from Sapium baccatum extract and use for control of tomato bacterial wilt.

    Directory of Open Access Journals (Sweden)

    Thuy Thu Vu

    Full Text Available In the search for new antibacterial agents from natural sources, we revealed that a crude methanol extract of Sapium baccatum was highly active against Ralstonia solanacearum, a causal agent of a serious disease called bacterial wilt of tomato. The bioassay-guided fractionation of this extract resulted in the isolation of seven known active compounds, including gallic acid, methyl gallate, corilagin, tercatain, chebulagic acid, chebulinic acid, and quercetin 3-O-α-L-arabinopyranoside. Their chemical structures were determined by electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. An in vitro antibacterial bioassay using a broth microdilution method revealed that, except for quercetin 3-O-α-L-arabinopyranoside (MIC = 250 μg/mL, the isolated compounds exhibited strong antibacterial activity against R. solanacearum (MIC = 26-52 μg/mL. Among the seven compounds, methyl gallate exhibited the strongest broad-spectrum activity against most of the plant pathogenic bacteria tested (MIC = 26-250 μg/mL. In the in vivo experiments, the crude extract of S. baccatum at 2000 and 1000 μg/mL reduced the development of tomato bacterial wilt by 83 and 63%, respectively, under greenhouse conditions after 14 days of infection. The results suggested that the extracts of S. baccatum or isolated tannins could be used as natural bactericides for the control of bacterial wilt of tomato.

  20. Fusarium wilt incidence and common bean yield according to the preceding crop and the soil tillage system

    Directory of Open Access Journals (Sweden)

    Eliane Divina de Toledo‑Souza

    2012-08-01

    Full Text Available The objective of this work was to evaluate the effects of preceding crops and tillage systems on the incidence of Fusarium wilt (Fusarium oxysporum f. sp. phaseoli and common bean (Phaseolus vulgaris yield. The cultivar BRS Valente was cultivated under center‑pivot irrigation in the winter seasons of 2003, 2004 and 2005, after several preceding crops established in the summer seasons. Preceding crops included the legumes Cajanus cajan (pigeon pea, Stylosanthes guianensis, and Crotalaria spectabilis; the grasses Pennisetum glaucum (millet, Sorghum bicolor (forage sorghum, Panicum maximum, and Urochloa brizantha; and a consortium of maize (Zea mays and U. brizantha (Santa Fé system. Experiments followed a strip‑plot design, with four replicates. Fusarium wilt incidence was higher in the no‑tillage system. Higher disease incidences corresponded to lower bean yields in 2003 and 2004. Previous summer cropping with U. brizantha, U. brizantha + maize consortium, and millet showed the lowest disease incidence. Therefore, the choice of preceding crops must be taken into account for managing Fusarium wilt on irrigated common bean crops in the Brazilian Cerrado.

  1. Conservation characteristics of wilted perennial ryegrass silage made using biological or chemical additives.

    Science.gov (United States)

    Conaghan, P; O'Kiely, P; O'Mara, F P

    2010-02-01

    The effects of 7 additive treatments on the fermentation and aerobic stability characteristics of wilted grass silage were studied under laboratory conditions. Treatments included no additive applied (untreated control), ammonium tetraformate at 3 and 6 L/t, homofermentative lactic acid bacteria alone ((ho)LAB), a mixture of Lactobacillus buchneri plus homofermentative lactic acid bacteria ((he+ho)LAB), and an antimicrobial mixture of sodium benzoate, sodium propionate, sodium nitrite, and hexamethylenetetramine at 2.5 and 5 L/t. Additives were compared across 3 consecutive harvests of 2 perennial ryegrass cultivars (AberDart and Fennema) following a 24-h wilt. Silos were opened after at least 100 d of ensilage and aerobic stability was assessed. Season of harvest had a large effect on grass composition at ensiling, producing herbages of relatively low (approximately 145g/kg), medium (approximately 250g/kg), and high (approximately 365g/kg) dry matter (DM) concentrations. Within harvests there were lesser differences between cultivars. The untreated control and (ho)LAB additive produced badly fermented silage from the low-DM herbages and well-fermented silage from the medium- and high-DM herbages. The ammonium tetraformate treatments produced both well-fermented and badly fermented silage from the low-DM herbages depending on cultivar, and consistently well-fermented silage from the medium- and high-DM herbages. The (he+ho)LAB silages had similar or slightly lower standard of fermentation than the untreated and (ho)LAB silages. The antimicrobial mixture produced more silages of lower standard of fermentation than the untreated control and ammonium tetraformate and (ho)LAB additives. All additive treatments, including the untreated control, failed to consistently increase residual water-soluble carbohydrate concentrations at silo opening. Ammonium tetraformate at 6 L/t was the most successful and (he+ho)LAB the least successful additive at increasing residual WSC

  2. Physiological and biochemical aspects of the resistance of banana plants to Fusarium wilt potentiated by silicon.

    Science.gov (United States)

    Fortunato, Alessandro Antonio; Rodrigues, Fabrício Ávila; do Nascimento, Kelly Juliane Teles

    2012-10-01

    Silicon amendments to soil have resulted in a decrease of diseases caused by several soilborne pathogens affecting a wide number of crops. This study evaluated the physiological and biochemical mechanisms that may have increased resistance of banana to Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense, after treatment with silicon (Si) amendment. Plants from the Grand Nain (resistant to F. oxysporum f. sp. cubense) and "Maçã" (susceptible to F. oxysporum f. sp. cubense) were grown in plastic pots amended with Si at 0 or 0.39 g/kg of soil (-Si or +Si, respectively) and inoculated with race 1 of F. oxysporum f. sp. cubense. Relative lesion length (RLL) and asymptomatic fungal colonization in tissue (AFCT) were evaluated at 40 days after inoculation. Root samples were collected at different times after inoculation with F. oxysporum f. sp. cubense to determine the level of lipid peroxidation, expressed as equivalents of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), total soluble phenolics (TSP), and lignin-thioglycolic acid (LTGA) derivatives; the activities of the enzymes phenylalanine ammonia-lyases glucanases (PALs), peroxidases (POXs), polyphenoloxidases (PPOs), β-1,3-glucanases (GLUs), and chitinases (CHIs); and Si concentration in roots. Root Si concentration was significantly increased by 35.3% for the +Si treatment compared with the -Si treatment. For Grand Nain, the root Si concentration was significantly increased by 12.8% compared with "Maçã." Plants from Grand Nain and "Maçã" in the +Si treatment showed significant reductions of 40.0 and 57.2%, respectively, for RLL compared with the -Si treatment. For the AFCT, there was a significant reduction of 18.5% in the +Si treatment compared with the -Si treatment. The concentration of MDA significantly decreased for plants from Grand Nain and "Maçã" supplied with Si compared with the -Si treatment while the

  3. Pattern of Flushing, Cherelle Wilt, and Accuracy of Yield Forecasting of Some Cocoa Clones

    Directory of Open Access Journals (Sweden)

    Adi Prawoto

    2014-08-01

    Full Text Available Monthly observation of cocoa flushing, number of cherelle wilt (CW, number of small, medium and large pods of 6 clones was conducted for two years to study its dynamics for one year. A study was conducted in Kaliwining Experimental Station, 45 m asl. and D rainfall type (according to Schmidt & Ferguson, using ICS 13, ICS 60, TSH 858, Sulawesi 1, Sulawesi 2 and KW 165 clones of 8 years old. Each clone was planted intermittently in separate rows, replicated 6 rows. Correlation and regression analysis were done between variables and with rainfall data. The parallel research was conducted in the similar station to assess the accuracy of production estimation method by identify percentage of small pods (length 1—10 cm, medium (11—15 cm and large pods (>15 cm to grow until harvested. The study used 15th years old trees of Sulawesi 1, Sulawesi 2, KW 165, KKM 22, ICS 13 and DR 2 clones. Each clones was replicated 5 times. The result showed that intensive flushing (>50% occured during January, March, September and November meanwhile no flushing during December and February. Correlation between rainfall and flushing was positive (r=0.27. Effect of clones on flushing frequency was similar but for flushing intensity was significant. KW 165 tended to be the lowest but TSH 858 tend to be the highest. CW occured for a year-round but the height level during May and June. Effect of clones was significant, KW 165 showed highest followed by Sulawesi 2. CW level showed positive correlation with number of medium (r=0.71 and big pods (r=0.55, except showed negative correlation with flushing intensity (r=-0.37 and rainfall (r=-0.51. High pod setting happened during May to November and low pod setting during December to March. In this aspect effect of clones were significant, the productive clones were Sulawesi 1, Sulawesi 2 and KW 165, but ICS 60 was the less. CW level during 1st semester was lower than at 2nd semester and clone effect was significant. The

  4. Utilization of Arbuscular Micorrhizal Fungi to Control Fusarium Wilt of Tomatoes

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    Theodorsius Pedai

    2015-12-01

    Full Text Available Tomato is a vegetable crop which is preferred by the Indonesian people. The problem encountered in tomato production is Fusarium wilt which is known as devastating disease. Studies have been done to solve the problem but effective and inexpensive control technique is still questioned. This study aimed to ascertain the ability of Arbuscular Mycorrhizal (AM fungi as biological control agent in reducing tomato Fusarium wilt. Research was arranged in a completely randomized design (CRD consisting of 5 treatments and 10 replications. The treatments were untreated plants, Fusarium oxysporum f.sp. lycopersici inoculated plants, AM fungi inoculated plants, AM fungi + F. oxysporum f.sp. lycopersici inoculated plants, F. oxysporum f.sp. lycopersici + benomyl inoculated plants. The results showed that plants which were inoculated with AM fungi had better growth compared to those which were not inoculated with AM fungi. Moreover, plants which were inoculated with AM fungi showed lower disease intensity compared to untreated plant and inoculated plant with F. oxysporum f.sp. lycopersici + benomyl application. Orthogonal contrast analysis showed plants treated with AM fungi significantly perform better growth and resistance towards infection compared with other treatments. Thus, it concluded that AM fungi had the potency as biological control agent.   INTISARI Tomat merupakan tanaman sayuran yang banyak digemari masyarakat Indonesia. Salah satu pengganggu utama pada tomat adalah penyakit layu Fusarium yang disebabkan oleh Fusarium oxysporum f.sp. lycopersici dan menimbulkan masalah yang serius. Kerugian yang ditimbulkan oleh penyakit tersebut sangat besar sehingga perlu dicari cara pengendalian yang murah, efektif, dan aman. Penelitian yang bertujuan untuk mengetahui kemampuan jamur mikoriza arbuskular (JMA sebagai agens pengendali hayati dalam menekan penyakit layu Fusarium pada tomat ini dilakukan dengan Rancangan Acak Lengkap (RAL yang terdiri atas 5

  5. Role of fusaric acid in the development of 'Fusarium wilt' symptoms in tomato: Physiological, biochemical and proteomic perspectives.

    Science.gov (United States)

    Singh, Vivek Kumar; Singh, Harikesh Bahadur; Upadhyay, Ram Sanmukh

    2017-09-01

    Fusarium wilt is one of the most prevalent and damaging diseases of tomato. Among various toxins secreted by the Fusarium oxysporum f. sp. lycopersici (causal agent of Fusarium wilt of tomato), fusaric acid (FA) is suspected to be a potent pathogenicity factor in tomato wilt disease development. With this rationale the present study was carried out with physiological, biochemical and proteomic perspectives. Treatment of FA was given to the leaves of tomato directly through infiltration to show the characteristic features of Fusarium wilt of tomato. The phytotoxic effect of FA was assessed in the form of cell death in tomato leaves which was observed by increased uptake of Evans blue stain. The measurement of electrolyte leakage was used as an indicator of the extent of cell death. The influence of FA on the leaf photosynthesis of tomato plant was investigated and it was found that FA strongly reduced the photosynthetic pigment contents of tomato leaves resulting to heavy suppression of leaf photosynthesis processes, which therefore affected leaf physiology finally leading to leaf wilting and necrosis. This cell death inducer (FA) produced an enormous oxidative burst during which large quantities of reactive oxygen species (ROS) like H2O2 was generated in the treated leaf tissues of tomato plants which was evident from enhancement in lipid peroxidation. To assess the involvement of proteolysis in the cell death cascade induced by FA treatment, total protease activity was measured in the leaf tissues and it was found that the total protease activity increased with the treatment and leading to cell death. Furthermore, proteomic study was used as a powerful tool to understand the alterations in cellular protein expression in response to FA exposure. Differential expression in several proteins was observed in the present study. Proteomic analyses, thus, clearly indicate that proteins belonging to different functional classes are significantly affected in the plant leaf

  6. Influence of mineral amendment on disease suppressive activity of Pseudomonas fluorescens to Fusarium wilt of chickpea.

    Science.gov (United States)

    Saikia, Ratul; Varghese, Saju; Singh, Bhim Pratap; Arora, Dilip K

    2009-01-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickpea. Pseudomonas fluorescens4-92 (Pf4-92) strain can suppress the disease. Amendment of zinc EDTA and copper EDTA could not suppress the disease significantly when used alone; however, they significantly suppressed the disease in presence of Pf4-92. In vitro observation showed that at 40, 30 and 20microgml(-1) concentrations of these minerals, i.e. Zn, Cu and Zn plus Cu, respectively, completely repressed the production of the phytotoxin, fusaric acid (FA). FA concentration (0.5microgml(-1)) has been shown to suppress the production of 2,4-diacetylphloroglucinol (DAPG) by Pf4-92, and DAPG, salicylic acid, pyochelin and pyoluteorin production was enhanced by these mineral amendments. In rockwool bioassays, Zn, Cu and Zn plus Cu amendments reduced FA production and enhanced DAPG production. This study demonstrates that Zn and Cu enhance biocontrol activity by reducing FA produced by the pathogen, F. oxysporum f. sp. ciceri.

  7. Restricted Spread of Tomato spotted wilt virus in Thrips-Resistant Pepper.

    Science.gov (United States)

    Maris, P C; Joosten, N N; Goldbach, R W; Peters, D

    2003-10-01

    ABSTRACT Spread of Tomato spotted wilt virus (TSWV) and population development of its vector Frankliniella occidentalis were studied on the pepper accessions CPRO-1 and Pikante Reuzen, which are resistant and susceptible to thrips, respectively. Viruliferous thrips were released on plants of each accession (nonchoice tests) or on plants in a 1:1 mixture of both accessions (choice tests) in small cages containing 8 or 16 plants. Significantly fewer CPRO-1 plants became infected in the primary infection phase in both tests. In the nonchoice test, virus infection of the resistant plants did not increase after the initial infection, but all plants eventually became infected when mixtures of both cultivars were challenged in the secondary infection phase. Secondary spread of TSWV from an infected resistant or susceptible source plant was significantly slower to resistant plants than to susceptible plants, independent of source plant phenotype. The restricted introduction and spread of TSWV in the thrips-resistant cultivar was confirmed in a large-scale greenhouse experiment. The restricted and delayed TSWV spread to plants of the resistant accession in both the cage and the greenhouse experiment was explained by impeded thrips population development. The results obtained indicate that thrips resistance may provide a significant protection to TSWV infection, even when the crop is fully susceptible to the virus.

  8. Pattern of the Occurrence of Tomato spotted wilt virus in Jeonnam Province

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    Sug-Ju Ko

    2013-12-01

    Full Text Available Tomato spotted wilt virus (TSWV was occurred at 8 areas including Naju, Suncheon, Younggwang, Youngam, and Shinan in Jeonnam province and the crops of Younggwang were severely damaged by TSWV. The hot pepper (Capsicum annuum, bell pepper (Capsicum annuum v ar. angulosum and tomato (Solanum lycopersicon in greenhouse and hot pepper in open field were infected by TSWV. Especially, hot pepper was severely damaged by TSWV infection. The survey data indicated that 1.1−30% in the nursery field at Naju, Suncheon, and Jangheung were infected by TSWV. Plants were infected by TSWV from early June to August. However, TSWV-infected seedlings from nursery fields showed the disease symptoms from May after transplanting. In pepper greenhouses, Frankliniella occidentalis was more dominant insect vector than Frankliniella intonsa. But in open field, the population of insect vector was opposed to greenhouse. In addition, the removal of weeds was able to delay the incidence of TSWV via side-window of greenhouse in Winter. Taken together, the control of weed and insect vector nearby side-window of greenhouse is important to prevent TSWV infection of plants.

  9. Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes.

    Science.gov (United States)

    Trojak-Goluch, Anna; Laskowska, Dorota; Agacka, Monika; Czarnecka, Diana; Kawka, Magdalena; Czubacka, Anna

    2011-12-01

    Black root rot (BRR) caused by Thielaviopsis basicola as well as Tomato spotted wilt virus (TSWV) are the most serious problems in tobacco growing regions. We crossed the breeding line WGL 3 carrying BRR resistance derived from N.glauca with the line PW-834 the resistance of which to TSWV was transferred from cultivar Polalta. Anthers obtained from F(1) hybrid plants were cultured to induce haploids combining resistance to Th. basicola and TSWV. Flow cytometry analysis revealed 242 haploids and 2 spontaneous doubled haploids among regenerants. All haploids were cloned and then evaluated for BRR as well as TSWV resistance. The presence of pathogens was detected by microscopic evaluation of roots or using DAS-ELISA test. Microscopic assessment showed that, 132 haploids had no symptoms of Th. basicola which, together with the absence of symptoms in the F(1) hybrids, indicated a dominant monogenic mode of inheritance. At the same time only 30 haploids demonstrated resistance to TSWV. SCAR markers associated with TSWV resistance gene detection was applied. The results indicate that small proportion of TSWV-resistant haploids is probably due to the influence of deleterious genes flanking the resistance factor that reduced vitality of gametophytes. Altogether, 24 haploids showed multiple resistance to Th. basicola and TSWV.

  10. Tissue tropism related to vector competence of Frankliniella occidentalis for tomato spotted wilt tospovirus.

    Science.gov (United States)

    Nagata, T; Inoue-Nagata, A K; Smid, H M; Goldbach, R; Peters, D

    1999-02-01

    The development of tomato spotted wilt tospovirus (TSWV) infection in the midgut and salivary glands of transmitting and non-transmitting thrips, Frankliniella occidentalis, was studied to elucidate tissue tropism and the virus pathway within the body of this vector. Immunohistological techniques used in this study showed that the midgut, foregut and salivary glands were the only organs in which virus accumulated. The first signals of infection, observed as randomly distributed fluorescent granular spots, were found in the epithelial cells of the midgut, mainly restricted to the anterior region. The virus subsequently spread to the circular and longitudinal midgut muscle tissues, a process which occurred late in the larval stage. In the adult stage, the infection occurred in the visceral muscle tissues, covering the whole midgut and foregut, and was abolished in the midgut epithelium. The infection of the salivary glands was first observed 72 h post-acquisition, and simultaneously in the ligaments connecting the midgut with these glands. The salivary glands of transmitting individuals appeared heavily or completely infected, while no or only a low level of infection was found in the glands of non-transmitting individuals. Moreover, the development of an age-dependent midgut barrier against virus infection was observed in second instar larvae and adults. The results show that the establishment of TSWV infection in the various tissues and the potential of transmission seems to be regulated by different barriers and processes related to the metamorphosis of thrips.

  11. Serological and molecular characterization of Syrian Tomato spotted wilt virus isolates

    Directory of Open Access Journals (Sweden)

    Faiz ISMAEIL

    2015-04-01

    Full Text Available Thirty four Syrian isolates of Tomato spotted wilt virus (TSWV collected from tomato and pepper were tested against five specific monoclonal antibodies using TAS-ELISA. The isolates were in two serogroups. Fourteen tomato and sixteen pepper isolates were similar in their reaction with MAb-2, MAb-4, MAb-5 and MAb-6, but did not react with MAb-7 (Serogroup 1. Meanwhile, four isolates collected from pepper reacted with all the MAbs used (Serogroup 2. The expected 620 bp DNA fragment was obtained by RT-PCR from six samples using a specific primer pair designed to amplify the nucleocapsid protein (NP gene of TSWV. The PCR products were sequenced and a phylogenetic tree was constructed. Sequence analysis revealed that the Syrian TSWV isolates were very similar at the nucleotide (97.74 to 99.84% identity and amino acid (96.17 to 99.03% identity sequences levels. The phylogenetic tree showed high similarity of Syrian TSWV isolates with many other representative isolates from different countries.

  12. Survival of Listeria monocytogenes in Wilted and Additive-Treated Grass Silage

    Science.gov (United States)

    Pauly, TM; Tham, WA

    2003-01-01

    Grass was field-dried to 3 different dry matter (DM) levels (200, 430 and 540 g/kg) and inoculated with 106–107 cfu/g of a Listeria monocytogenes strain sharing a phagovar occasionally involved in food-borne outbreaks of listeriosis. Formic acid (3 ml/kg) or lactic acid bacteria (8·105/g) with cellulolytic enzymes were applied only to forages with low and intermediate DM levels. Forages were ensiled in laboratory silos (1700 ml) and were stored at 25°C for 30 or 90 days. After 90 days of storage, L. monocytogenes could not be detected in any silo, except one with the high dry matter grass without additive. After 30 days of storage, between 102 and 106 cfu L. monocytogenes/g silage were isolated from the untreated silages. Increasing the DM content from 200 to 540 g/kg did not reduce listeria counts possibly because of the lower production of fermentation acids (higher pH). In silages treated with additives, counts of L. monocytogenes were always lower than in silages without additive. In wet silages (DM 200 g/kg) both additives were effective, but in the wilted silages (DM 430 g/kg) only the bacterial additive reduced listeria counts below detection level. Listeria counts were highly correlated to silage pH (r = 0.92), the concentration of lactic acid (r = -0.80) and the pooled amount of undissociated acids (r = -0.83). PMID:14650546

  13. Microbial taxa and functional genes shift in degraded soil with bacterial wilt

    Science.gov (United States)

    Zhang, Hongchun; Wang, Rui; Chen, Shu; Qi, Gaofu; He, Zhili; Zhao, Xiuyun

    2017-01-01

    Soil degradation is a serious global problem, but little is known about how soil microbial communities respond to soil degradation as well as their feedback to ecosystem functioning. In this study, we found the microbial community composition, structure and functional potential significantly altered in the degraded soils with bacterial wilt (termed as degraded soils). Compared with healthy soils, OTU richness of beneficial microorganisms were significantly decreased, but OTU richness of pathogenic microorganisms were significantly increased in the degraded soils. Functional gene array (GeoChip 5.0) analysis showed the functional metabolic potential of genes involved in stress, virulence, sulfur cycle, metal resistance, degradation of plant cell wall was significantly increased in the degraded soils. Increased functional metabolic potential of these genes may be related to the acidification and severe plant disease of degraded soils. Biological activity of degraded soils was obviously decreased with weakened soil enzyme activities when compared to the healthy soils. Soil pH and enzyme activities were negatively correlated with the abundance of genes involved in sulfur cycle, virulence, and stress responses. This study provides new insights into our understanding of soil microbial community responses to soil degradation. PMID:28051173

  14. Identification and isolation of Lactobacillus fructivorans from wilted alfalfa silage with and without molasses.

    Science.gov (United States)

    Wu, B; Nishino, N

    2016-03-01

    To gain insights into the bacterial species associated with anaerobic storage and aerobic stability of alfalfa silage. Wilted alfalfa silage (498 g dry matter kg(-1) ) was prepared with and without the addition of molasses. Aerobic spoilage tests were conducted at 5, 10 and 60 days after ensiling. The composition of fermentation products and the bacterial communities of silage were determined at 1, 3, 5 and 7 days after silo opening. Silage without molasses had small amounts of lactic and acetic acids detectable at silo opening but resisted deterioration due to aerobic spoilage for at least 5 days after opening. Resistance to aerobic deterioration in silage increased with the addition of molasses. The predominant bacterial species in molasses-added silage was Lactobacillus fructivorans, which was detected by denaturing gradient gel electrophoresis analysis. Different bacterial growth media were used for Lact. fructivorans isolation from alfalfa silage with added molasses: isolation was successful using liver infusion sake medium, but was unsuccessful when de Man, Rogosa and Sharpe medium was used. A nonconventional lactic acid bacterium (LAB) species may be involved in the high aerobic stability of alfalfa silage. The findings demonstrate that culture-independent microbiota analysis may be useful in the isolation and identification of nonconventional LAB species involved in fermentation and the aerobic stability of silage. © 2015 The Society for Applied Microbiology.

  15. CERATOCYSTIS WILT IN ‘UBÁ’ AND ‘DURA’ MANGO TREES UNDER WATER DEFICIT

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    SAULO DAVID REZENDE DA SILVA

    2017-10-01

    Full Text Available ABSTRACT The occurrence of water stress in mango trees grown in orchards located in semi-arid climates in Brazil is frequent. Water stress caused to plants may predispose them to the incidence of fungal diseases. The aim of this study was to evaluate the effect of water deficit on the incidence and severity of Ceratocystis wilt in mango trees considered resistant. Seedlings of ‘Ubá’ and ‘Dura’ were kept in pots and submitted to different water stress levels and inoculated with Ceratocystis fimbriata isolate (CEBS15. Mortality was low in ‘Ubá’ plants and high in ‘Dura’ plants. ‘Ubá’ plants showed lower severity and lesion length. In ‘Ubá’ plants, water deficit influenced the increase in lesion length. ‘Dura’ plants showed greater severity and lesion length, which were not affected by increasing water stress. It was concluded that ‘Ubá’ variety is resistant to fungus Ceratocystis fimbriata, even in severe drought conditions, while ‘Dura’ variety was not resistant to CEBS15 isolate, even under optimum irrigation conditions.

  16. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

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    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  17. Stability Analysis and Optimal Control Strategy for Prevention of Pine Wilt Disease

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    Kwang Sung Lee

    2014-01-01

    Full Text Available We propose a mathematical model of pine wilt disease (PWD which is caused by pine sawyer beetles carrying the pinewood nematode (PWN. We calculate the basic reproduction number R0 and investigate the stability of a disease-free and endemic equilibrium in a given mathematical model. We show that the stability of the equilibrium in the proposed model can be controlled through the basic reproduction number R0. We then discuss effective optimal control strategies for the proposed PWD mathematical model. We demonstrate the existence of a control problem, and then we apply both analytical and numerical techniques to demonstrate effective control methods to prevent the transmission of the PWD. In order to do this, we apply two control strategies: tree-injection of nematicide and the eradication of adult beetles through aerial pesticide spraying. Optimal prevention strategies can be determined by solving the corresponding optimality system. Numerical simulations of the optimal control problem using a set of reasonable parameter values suggest that reducing the number of pine sawyer beetles is more effective than the tree-injection strategy for controlling the spread of PWD.

  18. Symptom and Resistance of Cultivated and Wild Capsicum Accessions to Tomato Spotted Wilt Virus

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    Jung-Heon Han

    2011-04-01

    Full Text Available One hundred Capsicum accessions were screened for symptomatic response and resistance to Tomato spotted wilt virus-pb1 (TSWV-pb1. Symptom and its severity rating were checked by visual observation at 9, 12, 14, and 45 days after inoculation, respectively. Enzyme-linked immune-sorbent assay was performed all tested individuals on non-inoculated upper leaves after the third rating to indentify viral infection. Leaf curling was predominant in almost susceptible individuals of each accession. Stem necrosis was most frequent in wild species while yellowing in commercial hybrids and Korean land race cultivars. Ring spot, a typical symptom of TSWV, was rarely detected in some of a few accessions. Different levels of resistance to TSWV-pb1 were observed among the tested accessions. High level of resistance was detected in 4 commercial cultivars of Kpc- 35, -36, -57, and -62, and 8 wild species of PBI-11, C00105, PBC076, PBC280, PBC426, PBC495, PBC537, and PI201238 through seedling test by mechanical inoculation.

  19. The tomato xylem sap protein XSP10 is required for full susceptibility to Fusarium wilt disease.

    Science.gov (United States)

    Krasikov, Vladimir; Dekker, Henk L; Rep, Martijn; Takken, Frank L W

    2011-01-01

    XSP10 is an abundant 10 kDa protein found in the xylem sap of tomato. The protein displays structural similarity to plant lipid transfer proteins (LTPs). LTPs are involved in various physiological processes, including disease resistance, and some are able to bind and transfer diverse lipid molecules. XSP10 abundance in xylem sap declines upon infection with Fusarium oxysporum f. sp. lycopersici (Fol), implying involvement of XSP10 in the plant-pathogen interaction. Here, the biochemical characterization of XSP10 with respect to fatty acid-binding properties is reported; a weak but significant binding to saturated fatty acids was found. Furthermore, XSP10-silenced tomato plants were engineered and it was found that these plants exhibited reduced disease symptom development upon infection with a virulent strain of Fol. Interestingly, the reduced symptoms observed did not correlate with an altered expression profile for known reporter genes of plant defence (PR-1 and WIPI). This work demonstrates that XSP10 has lipid-binding properties and is required for full susceptibility of tomato to Fusarium wilt.

  20. Molecular interactions between tomato and its wilt pathogen Fusarium oxysporum f. sp. Lycopersici- a review

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    Adil ESSARIOUI

    2016-03-01

    Full Text Available Fusarium oxysporum f. sp. lycopersici Snyd. et Hans. (Fol is a soil-borne plant pathogen that causes wilt in tomato plants and threatens tomato industry worldwide. Successful plant infection and tissue colonization by Fol is an active process that involves a variety of cell wall degrading enzymes (CWDE, regulation of nutrient metabolism, and secretion of effectors to suppress and/or overcome the physical basal defense in tomato plants. Three effector-encoding avirulence genes have been identified and their combinations in the genome of Fol determine the 3 races of the pathogen. Avirulence genes and other pathogenicity factors are assembled in a lineage-specific genomic region, including 4 entire chromosomes that Fol acquired probably by horizontal gene transfer from other closely related species. In the course of co-evolution with Fol, tomato evolved 3 resistance genes to counteract pathogen effector-triggered disease. The interaction between tomato and Fol has become a model system for the study of the molecular basis of disease resistance and susceptibility in plants.

  1. Genetic Compositions of Broad bean wilt virus 2 Infecting Red Pepper in Korea

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    Hae-Ryun Kwak

    2013-09-01

    Full Text Available The incidence of Broad bean wilt virus 2 (BBWV2 on red pepper was investigated using the samples obtained from 24 areas of 8 provinces in Korea. Two hundred and five samples (79% out of 260 collected samples were found to be infected with BBWV2. While the single infection rate of BBWV2 was 21.5%, the co-infection rate of BBWV2 with Cucumber mosaic virus, Pepper mottle virus, Pepper mild mottle virus and/or Potato virus Y was 78.5%. To characterize the genetic diversity of BBWV2 Korean isolates, 7 isolates were fully sequenced and analyzed. Phylogenetic analyses revealed that BBWV2 isolates could be divided largely into two groups as Group I and Group II. Based on the partial sequence analyses, 153 selected BBWV2 isolates were subgrouped into GS-I (21.6%, GS-II (3.9% and GS-III (56.9%. BBWV2 GS-III, which was predominant in Korea, appears to be a new combination between Group I RNA-1 and Group II RNA-2. Viral disease incidence of BBWV2 on red pepper was under 2% before 2004. However, the incidence was increased abruptly to 41.3% in 2005, 58.2% in 2006 and 79% in 2007. These rapid increases might be related with the emergence of new combinations between BBWV2 groups.

  2. The Ve-mediated resistance response of the tomato to Verticillium dahliae involves H2O2, peroxidase and lignins and drives PAL gene expression

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    Merino Fuencisla

    2010-10-01

    Full Text Available Abstract Background Verticillium dahliae is a fungal pathogen that infects a wide range of hosts. The only known genes for resistance to Verticillium in the Solanaceae are found in the tomato (Solanum lycopersicum Ve locus, formed by two linked genes, Ve1 and Ve2. To characterize the resistance response mediated by the tomato Ve gene, we inoculated two nearly isogenic tomato lines, LA3030 (ve/ve and LA3038 (Ve/Ve, with V. dahliae. Results We found induction of H2O2 production in roots of inoculated plants, followed by an increase in peroxidase activity only in roots of inoculated resistant plants. Phenylalanine-ammonia lyase (PAL activity was also increased in resistant roots 2 hours after inoculation, while induction of PAL activity in susceptible roots was not seen until 48 hours after inoculation. Phenylpropanoid metabolism was also affected, with increases in ferulic acid, p-coumaric acid, vanillin and p-hydroxybenzaldehyde contents in resistant roots after inoculation. Six tomato PAL cDNA sequences (PAL1 - PAL6 were found in the SolGenes tomato EST database. RT-PCR analysis showed that these genes were expressed in all organs of the plant, albeit at different levels. Real-time RT-PCR indicated distinct patterns of expression of the different PAL genes in V. dahliae-inoculated roots. Phylogenetic analysis of 48 partial PAL cDNAs corresponding to 19 plant species grouped angiosperm PAL sequences into four clusters, suggesting functional differences among the six tomato genes, with PAL2 and PAL6 presumably involved in lignification, and the remaining PAL genes implicated in other biological processes. An increase in the synthesis of lignins was found 16 and 28 days after inoculation in both lines; this increase was greater and faster to develop in the resistant line. In both resistant and susceptible inoculated plants, an increase in the ratio of guaiacyl/syringyl units was detected 16 days after inoculation, resulting from the lowered amount

  3. Effects of soil solarization and some amendments to control ...

    African Journals Online (AJOL)

    hope&shola

    2010-10-04

    borne pathogens ... samples of diseased trees were confirmed by pathogen isolations from affected twigs during the ..... mulching for controlling Verticillium wilt in established pistachio nut groves. Phytopathology, 72: 243- 246.

  4. Molecular research and genetic engineering of resistance to ...

    African Journals Online (AJOL)

    Molecular research and genetic engineering of resistance to Verticillium wilt in cotton: A review. ... African Journal of Biotechnology. Journal Home · ABOUT · Advanced Search · Current Issue ... Article Metrics. Metrics Loading ... Metrics ...

  5. Association mapping to discover significant marker-trait associations for resistance against fusarium wilt variant 2 in pigeonpea [Cajanus cajan (L.) Millspaugh] using SSR markers.

    Science.gov (United States)

    Patil, Prakash G; Dubey, Jyotirmay; Bohra, Abhishek; Mishra, R K; Saabale, P R; Das, Alok; Rathore, Meenal; Singh, N P

    2017-08-01

    Pigeonpea production is severely constrained by wilt disease caused by Fusarium udum. In the current study, we discover the putative genomic regions that control resistance response to variant 2 of fusarium wilt using association mapping approach. The association panel comprised of 89 diverse pigeonpea genotypes including seven varieties, three landraces and 79 germplasm lines. The panel was screened rigorously for 3 consecutive years (2013-14, 2014-15 and 2015-2016) against variant 2 in a wilt-sick field. A total of 65 pigeonpea specific hypervariable SSR markers (HASSRs) were screened representing seven linkage groups and 29 scaffolds of the pigeonpea genome. A total of 181 alleles were detected, with average values of gene diversity and polymorphism information content (PIC) of 0.55 and 0.47, respectively. Further analysis using model based (STRUCTURE) and distance based (clustering) approaches separated the entire pigeonpea collection into two distinct subgroups (K = 2). The marker trait associations (MTAs) were established based on three-year wilt incidence data and SSR dataset using a unified mixed linear model. Consequently, six SSR markers were identified, which were significantly associated with wilt resistance and explained up to 6% phenotypic variance (PV) across the years. Among these SSRs, HASSR18 was found to be the most stable and significant, accounting for 5-6% PV across the years. To the best of our knowledge, this is the first report of identification of favourable alleles for resistance to variant 2 of Fusarium udum in pigeonpea using association mapping. The SSR markers identified here will greatly facilitate marker assisted resistance breeding against fusarium wilt in pigeonpea.

  6. Preliminary Report on Diseases of Tomato in Choba, Rivers State ...

    African Journals Online (AJOL)

    Fusarium oxysporum f. sp. lycopersici, Verticillium albo-atrum and Rhizoctonia solani were the three fungi isolated on acidified potato dextrose agar from symptomatic roots and stems of permanently wilted plant samples. Pathogenicity of isolates was established. There is evidence to suggest that Fusarium, Verticillium and ...

  7. Genome and Transcriptome Analysis of the Fungal Pathogen Fusarium oxysporum f. sp. cubense Causing Banana Vascular Wilt Disease

    Science.gov (United States)

    Zeng, Huicai; Fan, Dingding; Zhu, Yabin; Feng, Yue; Wang, Guofen; Peng, Chunfang; Jiang, Xuanting; Zhou, Dajie; Ni, Peixiang; Liang, Changcong; Liu, Lei; Wang, Jun; Mao, Chao

    2014-01-01

    Background The asexual fungus Fusarium oxysporum f. sp. cubense (Foc) causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.). To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced. Methodology/Principal Findings Genome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1), the Foc race 4 isolate (Foc4) has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana ‘Brazil’ in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety ‘Brazil’. Conclusions/Significance Foc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will thus advance

  8. Effects of Thrips Density, Mode of Inoculation, and Plant Age on Tomato Spotted Wilt Virus Transmission in Peanut Plants.

    Science.gov (United States)

    Shrestha, Anita; Sundaraj, Sivamani; Culbreath, Albert K; Riley, David G; Abney, Mark R; Srinivasan, Rajagopalbabu

    2015-02-01

    Spotted wilt caused by tomato spotted wilt virus (TSWV; family Bunyaviridae; genus Tospovirus) is a serious disease of peanut (Arachis hypogaea L.) in the southeastern United States. Peanut genotypes with field resistance to TSWV are effective in suppressing spotted wilt. All commercially available genotypes with field resistance to TSWV were developed through conventional breeding. As a part of the breeding process, peanut genotypes are regularly screened under field situations. Despite numerous advantages associated with field screening, it is often limited by inconsistent vector (thrips) and TSWV pressure. A greenhouse transmission protocol would aid in thorough screening of selected genotypes and conserve time. In this study, various parameters associated with TSWV transmission, including tobacco thrips, Frankliniella fusca (Hinds) density, mode of inoculation, and plant age, were evaluated. Greater incidences of TSWV infection were obtained with thrips-mediated inoculation when compared with mechanical inoculation. TSWV inoculation with three, five, and 10 thrips resulted in greater incidences of TSWV infection in plants than inoculation with one thrips. However, incidences of TSWV infection did not vary between plants inoculated with three, five, and 10 viruliferous thrips. With both thrips-mediated and mechanical inoculation methods, incidences of TSWV infection in 1-wk-old plants were greater than in 4-wk-old plants. TSWV copy numbers, as determined by qPCR, also decreased with plant age. Results suggest that using at least three thrips per plant and 1- to 2-wk-old plants would maximize TSWV infection in inoculated plants. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. [Effect of antagonistic bacteria and soil disinfectant on soil bacterium community in banana Fusarium wilt disease area].

    Science.gov (United States)

    Zhou, Dengbo; Jing, Tao; Tan, Xin; Chen, Bo; Zhang, Xiyan; Gao, Zhufen

    2013-08-04

    The objective of the present study is to elucidate the effects of the application of cake fertilizer fermentation fluid with antagonistic bacteria and soil disinfectant chlorine dioxide on the occurrence of banana fusarium wilt disease and soil bacterium community. Under the field cultivation conditions, the Biolog and T-RFLP method was used to investigate the soil bacterium diversity and community features in different treatments at different periods. The results show that both cake fertilizer fermentation fluid with antagonistic bacteria and soil disinfectant could reduce disease index of banana fusarium wilt disease significantly, the highest control effect could reach 60.82% with the combined application of these two methods. The result of Biolog eco plate shows that the application of cake fertilizer fermentation fluid with antagonistic bacteria could improve soil microbial AWCD (average well color development) and population uniformity, the use of soil disinfectant significantly reduced the soil microbial population's abundance and the uniformity. Principal component analysis shows that the soil microbial population using carbon source had an increasing trend throughout the banana growing season, the main carbon sources in the early stage were amino acids, carboxylic acids, amphiphilic compounds and carbohydrates, and the increased main carbon sources in the later stage were carboxylic acids and amphiphilic compounds. Soil bacterial diversity analysis by T-RFLP shows that the treatments of cake fertilizer fermentation fluid with antagonistic bacteria had the highest bacterial TRFs (Terminal restriction fragment) fragments, which resulted from the increase of Flavobacterium, Pseudomona and Lactobacillus population in the soil. The application of cake fertilizer fermentation fluid with antagonistic bacteria combining soil disinfectant could increase antagonistic microorganisms species, enhance soil microbial diversity, improve soil microbial ecological

  10. Quantitative Trait Loci in Sweet Corn Associated with Partial Resistance to Stewart's Wilt, Northern Corn Leaf Blight, and Common Rust.

    Science.gov (United States)

    Brown, A F; Juvik, J A; Pataky, J K

    2001-03-01

    ABSTRACT Partial resistance to Stewart's wilt (Erwina stewartii, syn. Pantoea stewartii), northern corn leaf blight (NCLB) (Exserohilum turcicum), and common rust (Puccinia sorghi) was observed in an F(2:3) population developed from a cross between the inbred sweet corn lines IL731a and W6786. The objective of this study was to identify quantitative trait loci (QTL) associated with partial resistance using restriction fragment length polymorphic markers. Phenotypic data were collected for 2 years for Stewart's wilt, NCLB, and common rust but, due to significant family-environment interaction, analysis was conducted individually on data from each year. In 2 years of evaluation for the three diseases, a total of 33 regions in the maize genome were associated with partial resistance describing from 5.9 to 18% of the total phenotypic variability. Of six regions common in both years, three were associated with partial resistance to Stewart's wilt (chromosomes 4:07, 5:03, and 6:04), one was associated with NCLB (chromosome 9:05), and two were associated with common rust (chromosomes 2:04 and 3:04). The rust QTL on 3S mapped to within 20 cM of the rp3 locus and explained 17.7% of the phenotypic variability. Some of the QTL associated with partial resistance to the three diseases have been reported previously, and some are described here for the first time. Results suggest it may be possible to consolidate QTL from various elite backgrounds in a manner analogous to the pyramiding of major resistance genes. We also report here on two QTL associated with anthocyanin production on chromosomes 10:6 and 5:03 in the general location of the a2 gene.

  11. Influence of soil type, cultivar and Verticillium dahliae on the structure of the root and rhizosphere soil fungal microbiome of strawberry.

    Science.gov (United States)

    Nallanchakravarthula, Srivathsa; Mahmood, Shahid; Alström, Sadhna; Finlay, Roger D

    2014-01-01

    Sustainable management of crop productivity and health necessitates improved understanding of the ways in which rhizosphere microbial populations interact with each other, with plant roots and their abiotic environment. In this study we examined the effects of different soils and cultivars, and the presence of a soil-borne fungal pathogen, Verticillium dahliae, on the fungal microbiome of the rhizosphere soil and roots of strawberry plants, using high-throughput pyrosequencing. Fungal communities of the roots of two cultivars, Honeoye and Florence, were statistically distinct from those in the rhizosphere soil of the same plants, with little overlap. Roots of plants growing in two contrasting field soils had high relative abundance of Leptodontidium sp. C2 BESC 319 g whereas rhizosphere soil was characterised by high relative abundance of Trichosporon dulcitum or Cryptococcus terreus, depending upon the soil type. Differences between different cultivars were not as clear. Inoculation with the pathogen V. dahliae had a significant influence on community structure, generally decreasing the number of rhizosphere soil- and root-inhabiting fungi. Leptodontidium sp. C2 BESC 319 g was the dominant fungus responding positively to inoculation with V. dahliae. The results suggest that 1) plant roots select microorganisms from the wider rhizosphere pool, 2) that both rhizosphere soil and root inhabiting fungal communities are influenced by V. dahliae and 3) that soil type has a stronger influence on both of these communities than cultivar.

  12. Real-Time PCR Detection and QUantification of Soilborne Fungal Pathogens : the Case of Rosellinia necatrix, Phytophthora nicotianae, P. citrophthora and Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    L. Schena

    2004-08-01

    Full Text Available Conventional and Scorpion primers were designed from the ITS regions to identify Rosellinia necatrix, Phytophthora nicotianae, and P. citrophthora and from the IGS regions to identify Verticillium dahliae and V. alboatrum. Specificity of primers and probes was assessed using genomic DNA from a large number of fungi from several hosts and by means of BLAST analyses, to exclude the presence of similar sequences in other micro-organisms among available DNA databases (GenBank. Simple and rapid procedures for DNA extraction from naturally infected matrices (soils, roots, bark, and/or woody tissues were utilised to yield DNA of a purity and quality suitable for PCR assays. Combining these protocols with a double amplification (nested Scorpion-PCR, the real-time detection of these pathogens was possible from naturally infested soils and from infected citrus roots (P. nicotianae and P. citrophthora, from the roots and bark of stone fruits and olive (R. necatrix and from olive branches (V. dahliae. For target pathogens, the limit of detection was 1 pg µl-1 in Scorpion-PCR and 1 fg µl-1 in nested Scorpion-PCR. High and significant correlations between pathogen propagule concentrations and real-time PCR cycle thresholds (Ct were obtained. Moreover, specific tests with R. necatrix seem to indicate that its DNA is quite rapidly degraded in the soil, excluding the risk of false positives due to the presence of dead cells.

  13. Comparative genomics reveals cotton-specific virulence factors in flexible genomic regions in Verticillium dahliae and evidence of horizontal gene transfer from Fusarium.

    Science.gov (United States)

    Chen, Jie-Yin; Liu, Chun; Gui, Yue-Jing; Si, Kai-Wei; Zhang, Dan-Dan; Wang, Jie; Short, Dylan P G; Huang, Jin-Qun; Li, Nan-Yang; Liang, Yong; Zhang, Wen-Qi; Yang, Lin; Ma, Xue-Feng; Li, Ting-Gang; Zhou, Lei; Wang, Bao-Li; Bao, Yu-Ming; Subbarao, Krishna V; Zhang, Geng-Yun; Dai, Xiao-Feng

    2018-01-01

    Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce). Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed. The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer. Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  14. Ectopic expression of a novel Ser/Thr protein kinase from cotton (Gossypium barbadense), enhances resistance to Verticillium dahliae infection and oxidative stress in Arabidopsis.

    Science.gov (United States)

    Zhang, Yan; Wang, Xingfen; Li, Yiyi; Wu, Lizhu; Zhou, Hongmei; Zhang, Guiyin; Ma, Zhiying

    2013-11-01

    Overexpression of a cotton defense-related gene GbSTK in Arabidopsis resulted in enhancing pathogen infection and oxidative stress by activating multiple defense-signaling pathways. Serine/threonine protein kinase (STK) plays an important role in the plant stress-signaling transduction pathway via phosphorylation. Most studies about STK genes have been conducted with model species. However, their molecular and biochemical characterizations have not been thoroughly investigated in cotton. Here, we focused on one such member, GbSTK. RT-PCR indicated that it is induced not only by Verticillium dahliae Kleb., but also by signaling molecules. Subcellular localization showed that GbSTK is present in the cell membrane, cytoplasm, and nucleus. Overexpression of GbSTK in Arabidopsis resulted into the enhanced resistance to V. dahliae. Moreover, Overexpression of GbSTK elevated the expression of PR4, PR5, and EREBP, conferring on transgenic plants enhanced reactive oxygen species scavenging capacity and oxidative stress tolerance. Our results suggest that GbSTK is active in multiple defense-signaling pathways, including those involved in responses to pathogen infection and oxidative stress.

  15. The pmk1-like mitogen-activated protein kinase from Lecanicillium (Verticillium) fungicola is not required for virulence on Agaricus bisporus.

    Science.gov (United States)

    Collopy, Patrick D; Amey, Richard C; Sergeant, Martin J; Challen, Michael P; Mills, Peter R; Foster, Gary D; Bailey, Andy M

    2010-05-01

    In plant-pathogenic fungi, the pmk1 mitogen-activated protein kinase (MAPK) signalling pathway plays an essential role in regulating the development of penetration structures and the sensing of host-derived cues, but its role in other pathosystems such as fungal-fungal interactions is less clear. We report the use of a gene disruption strategy to investigate the pmk1-like MAPK, Lf pmk1 in the development of Lecanicillium fungicola (formerly Verticillium fungicola) infection on the cultivated mushroom Agaricus bisporus. Lf pmk1 was isolated using a degenerate PCR-based approach and was shown to be present in a single copy by Southern blot analysis. Quantitative RT-PCR showed the transcript to be fivefold upregulated in cap lesions compared with pure culture. Agrobacterium-mediated targeted disruption was used to delete a central portion of the Lf pmk1 gene. The resulting mutants showed normal symptom development as assessed by A. bisporus mushroom cap assays, sporulation patterns were normal and there were no apparent changes in overall growth rates. Our results indicate that, unlike the situation in fungal-plant pathogens, the pmk1-like MAPK pathway is not required for virulence in the fungal-fungal interaction between the L. fungicola pathogen and A. bisporus host. This observation may be of wider significance in other fungal-fungal and/or fungal-invertebrate interactions.

  16. Analysis of the Tomato spotted wilt virus ambisense S RNA-encoded hairpin structure in translation.

    Directory of Open Access Journals (Sweden)

    Christina Geerts-Dimitriadou

    Full Text Available BACKGROUND: The intergenic region (IR of ambisense RNA segments from animal- and plant-infecting (-RNA viruses functions as a bidirectional transcription terminator. The IR sequence of the Tomato spotted wilt virus (TSWV ambisense S RNA contains stretches that are highly rich in A-residues and U-residues and is predicted to fold into a stable hairpin structure. The presence of this hairpin structure sequence in the 3' untranslated region (UTR of TSWV mRNAs implies a possible role in translation. METHODOLOGY/PRINCIPAL FINDINGS: To analyse the role of the predicted hairpin structure in translation, various Renilla luciferase constructs containing modified 3' and/or 5' UTR sequences of the TSWV S RNA encoded nucleocapsid (N gene were analyzed for expression. While good luciferase expression levels were obtained from constructs containing the 5' UTR and the 3' UTR, luciferase expression was lost when the hairpin structure sequence was removed from the 3' UTR. Constructs that only lacked the 5' UTR, still rendered good expression levels. When in addition the entire 3' UTR was exchanged for that of the S RNA encoded non-structural (NSs gene transcript, containing the complementary hairpin folding sequence, the loss of luciferase expression could only be recovered by providing the 5' UTR sequence of the NSs transcript. Luciferase activity remained unaltered when the hairpin structure sequence was swapped for the analogous one from Tomato yellow ring virus, another distinct tospovirus. The addition of N and NSs proteins further increased luciferase expression levels from hairpin structure containing constructs. CONCLUSIONS/SIGNIFICANCE: The results suggest a role for the predicted hairpin structure in translation in concert with the viral N and NSs proteins. The presence of stretches highly rich in A-residues does not rule out a concerted action with a poly(A-tail-binding protein. A common transcription termination and translation strategy for plant

  17. Potential distribution of pine wilt disease under future climate change scenarios.

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    Akiko Hirata

    Full Text Available Pine wilt disease (PWD constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22. For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5 and two time periods (2050s and 2070s. We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area. Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

  18. Expression and characterization of a soluble form of tomato spotted wilt virus glycoprotein GN.

    Science.gov (United States)

    Whitfield, Anna E; Ullman, Diane E; German, Thomas L

    2004-12-01

    Tomato spotted wilt virus (TSWV), a member of the Tospovirus genus within the Bunyaviridae, is an economically important plant pathogen with a worldwide distribution. TSWV is transmitted to plants via thrips (Thysanoptera: Thripidae), which transmit the virus in a persistent propagative manner. The envelope glycoproteins, G(N) and G(C), are critical for the infection of thrips, but they are not required for the initial infection of plants. Thus, it is assumed that the envelope glycoproteins play important roles in the entry of TSWV into the insect midgut, the first site of infection. To directly test the hypothesis that G(N) plays a role in TSWV acquisition by thrips, we expressed and purified a soluble, recombinant form of the G(N) protein (G(N)-S). The expression of G(N)-S allowed us to examine the function of G(N) in the absence of other viral proteins. We detected specific binding to thrips midguts when purified G(N)-S was fed to thrips in an in vivo binding assay. The TSWV nucleocapsid protein and human cytomegalovirus glycoprotein B did not bind to thrips midguts, indicating that the G(N)-S-thrips midgut interaction is specific. TSWV acquisition inhibition assays revealed that thrips that were concomitantly fed purified TSWV and G(N)-S had reduced amounts of virus in their midguts compared to thrips that were fed TSWV only. Our findings that G(N)-S binds to larval thrips guts and decreases TSWV acquisition provide evidence that G(N) may serve as a viral ligand that mediates the attachment of TSWV to receptors displayed on the epithelial cells of the thrips midgut.

  19. Potential distribution of pine wilt disease under future climate change scenarios.

    Science.gov (United States)

    Hirata, Akiko; Nakamura, Katsunori; Nakao, Katsuhiro; Kominami, Yuji; Tanaka, Nobuyuki; Ohashi, Haruka; Takano, Kohei Takenaka; Takeuchi, Wataru; Matsui, Tetsuya

    2017-01-01

    Pine wilt disease (PWD) constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22). For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5) and two time periods (2050s and 2070s). We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area). Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

  20. Potential distribution of pine wilt disease under future climate change scenarios

    Science.gov (United States)

    Nakamura, Katsunori; Nakao, Katsuhiro; Kominami, Yuji; Tanaka, Nobuyuki; Ohashi, Haruka; Takano, Kohei Takenaka; Takeuchi, Wataru; Matsui, Tetsuya

    2017-01-01

    Pine wilt disease (PWD) constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22). For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5) and two time periods (2050s and 2070s). We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area). Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD. PMID:28797067

  1. Use of additives and pre-wilting in Tifton 85 bermudagrass silage production

    Directory of Open Access Journals (Sweden)

    Marcela Abbado Neres

    2014-02-01

    Full Text Available The use of tropical grasses silage has become common in ruminant feed. An experiment was conducted to evaluate the fermentation characteristics, nutritional value, pH, fermentative capacity, ammonia nitrogen / total nitrogen (NH3N/total N of Tifton 85 bermudagrass grass silage with different additives and wilting. The treatments were: pre-drying in the sun for two hours before silage, use of inoculant-enzymatic addition of soybean hulls, corn grits addition and use of salt in the surface layer of the silo. The experimental design was completely randomized with 6 treatments and 4 replications. Plants of Tifton 85 bermudagrass with 38 days of growth were ensiled in experimental silos with Bunsen valve type with packing densities of 236 kg of silage per m³ for Tifton 85 bermudagrass pre-dried in the sun and 294 kg of silage per m³ for the other treatments. The proportions of soybean hulls and corn grits added to the silage were calculated based on the initial DM content of Tifton 85 bermudagrass order to obtain MS 320 g kg-1 for the material to be ensiled. The buffering capacity did not differ between treatments in getting 29.56 (meqHCl/100gMS. It was found that the concentration of ammonia nitrogen did not differ between silages and remained low (3.22 g kg-1, the pH after silo opening was also similar with an average of 4.09 getting above 4.2 only in Tifton 85 bermudagrass silage without pre-treatment. The crude protein was higher in silages Tifton 85 bermudagrass and Tifton 85 bermudagrass with soybean hulls (17.48 g kg-1. The use corn grits caused a reduction in the values of NDF. The use of salt on the surface the layer reduced the production of latic and acetic acid.

  2. Association Mapping for Fusarium Wilt Resistance in Chinese Asparagus Bean Germplasm

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    Xinyi Wu

    2015-07-01

    Full Text Available Fusarium wilt (FW is an important vascular disease attacking asparagus bean [ (L. Walp. subsp. Sesquipedalis Group] in China. The level and genetic variability of FW resistance in the Chinese asparagus bean germplasm remains elusive. In the current study, FW resistance was assessed across a natural population consisting of 95 asparagus bean and four African cowpea [ (L. Walp. subsp. Unguiculata Group] accessions. The disease index (DI based on the severity of leaf damage (LFD and vascular discoloration (VD varied highly across the population and the highly resistant varieties used for vegetable are very limited. Genome-wide association study identified 11 and seven single nucleotide polymorphisms (SNPs that are associated with LFD and VD traits, respectively. These SNPs were distributed on nine linkage groups of the asparagus bean genome and each accounted for less than 5% of the phenotypic variation. Overall, the nonstandard vegetable (NSV subgene pool harbors favorable alleles in a higher frequency than the standard vegetable (SV subgene pool. Individual NSV-type accessions tend to possess a greater number of favorable alleles than the SV-type ones. A SNP marker 1_0981 was converted to a cleaved amplified polymorphic sequences (CAPS marker to facilitate future breeding. To our knowledge, this is the first report of an association mapping (AM study in asparagus bean. The results obtained suggests that resources for FW resistance is relatively limited in the SV subgene pool; hence, introducing resistant alleles from the NSV accessions into currently leading SV cultivars will be important to improve FW resistance of the latter.

  3. Native cell-death genes as candidates for developing wilt resistance in transgenic banana plants.

    Science.gov (United States)

    Ghag, Siddhesh B; Shekhawat, Upendra K Singh; Ganapathi, Thumballi R

    2014-07-04

    In order to feed an ever-increasing world population, there is an urgent need to improve the production of staple food and fruit crops. The productivity of important food and fruit crops is constrained by numerous biotic and abiotic factors. The cultivation of banana, which is an important fruit crop, is severely threatened by Fusarium wilt disease caused by infestation by an ascomycetes fungus Fusarium oxysporum f. sp. cubense (Foc). Since there are no established edible cultivars of banana resistant to all the pathogenic races of Foc, genetic engineering is the only option for the generation of resistant cultivars. Since Foc is a hemibiotrophic fungus, investigations into the roles played by different cell-death-related genes in the progression of Foc infection on host banana plants are important. Towards this goal, three such genes namely MusaDAD1, MusaBAG1 and MusaBI1 were identified in banana. The study of their expression pattern in banana cells in response to Foc inoculation (using Foc cultures or fungal toxins like fusaric acid and beauvericin) indicated that they were indeed differentially regulated by fungal inoculation. Among the three genes studied, MusaBAG1 showed the highest up-regulation upon Foc inoculation. Further, in order to characterize these genes in the context of Foc infection in banana, we generated transgenic banana plants constitutively overexpressing the three genes that were later subjected to Foc bioassays in a contained greenhouse. Among the three groups of transgenics tested, transformed banana plants overexpressing MusaBAG1 demonstrated the best resistance towards Foc infection. Further, these plants also showed the highest relative overexpression of the transgene (MusaBAG1) among the three groups of transformed plants generated. Our study showed for the first time that native genes like MusaBAG1 can be used to develop transgenic banana plants with efficient resistance towards pathogens like Foc. Published by Oxford University Press

  4. Stable integration and expression of a plant defensin in tomato confers resistance to fusarium wilt.

    Science.gov (United States)

    Abdallah, Naglaa A; Shah, Dilip; Abbas, Dina; Madkour, Magdy

    2010-01-01

    Plant defensins are small cysteine-rich peptides which belong to a group of pathogenasis related defense mechanism proteins. The proteins inhibit the growth of a broad range of microbes and are highly stable under extreme environmental stresses. Tomato cultivation is affected by fungal disease such as Fusarium wilt. In order to overcome fungal damages, transgenic tomato plants expressing the Medicago sativa defensin gene MsDef1 under the control of the CaMV 35S promoter were developed. The Fusarium-susceptible tomato (Lycobersicum esculentum Mill) cultivar CastleRock was used for transformation to acquire fungal resistance. Hypocotyl with a part of cotyledon (hypocotyledonary) for young tomato seedlings were used as an explant material and transformation was performed using the biolistic delivery system. Bombarded shoots were selected on regeneration medium supplemented with hygromycin and suitable concentrations of BA, zeatin ripozide and AgNO(3). Putative transgenic plantlets of T(0) were confirmed by PCR analysis using primers specific for the transgene and the transformation frequency obtained was 52.3%. Transformation and transcription of transgenes were confirmed in T(1) by PCR, Southern hybridizations, and reverse-transcription PCR (RT-PCR). The copy numbers of integrated transgene into tomato genome ranged between 1-3 copies. Greenhouse bioassay was performed on the transgenic T(1) and T(2) young seedlings and non-transgenic controls by challenging with a vigorous isolate of the fungal pathogen Fusarium oxysporum f. sp. Lycopersici. The level of fungal infectivity was determined using RT-PCR with tomatinase specific primers. Transgenic lines were more resistant to infection by fusarium than the control plants. These results indicated that overexpressing defensins in transgenic plants confer resistance to fungal pathogens.

  5. Colonization of Tomato Root by Antagonistic Bacterial Strains to Fusarium Wilt of Tomato

    Directory of Open Access Journals (Sweden)

    Arif Wibowo

    2005-12-01

    Full Text Available Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici (Fol is an important disease in tomato which cause a significant loss of yield in major growing regions of the world. This study examined the ability of bacterial strains antagonistic to F. oxysporum f.sp. lycopersici (H5, H22, H63, H71, Burkholderia cepacia strain 65 and 526 to colonize tomato seedlings and the effect of plant growth. The effect of bacterial population size and air temperature on the bacterial colonization and their spread along the root systems was also assessed.The results of this study showed that the bacterial population at 28°/23° C day/night temperature 14 days after planting was significantly greater than 23°/18° C for 4 of 6 strains tested. Although there was no significant effect of temperature on bacterial population observed in this study, the ability of the baacterial strains to colonize the rhizosphere was significantly different. Three strains (H5, B. cepacia strain 65 and 526 survived well in the rhizosphere and at 4 weeks after planting rhizosphere populations per gram fresh root were not significantly different from those recovered 2 weeks after planting. The largest population of the bacterial inoculants developed in the basal region of the roots and this differed between strains by log10 2.7 cfu/cm root. The bacterial populations in other parts of the root were also strain dependent. Strain H71, for example, was able to colonize the root segments at a high population level. However strain H63 was recovered only in small number in all root segments.

  6. Impact of Laurel Wilt, Caused by Raffaelea lauricola, on Leaf Gas Exchange and Xylem Sap Flow in Avocado, Persea americana.

    Science.gov (United States)

    Ploetz, Randy C; Schaffer, Bruce; Vargas, Ana I; Konkol, Joshua L; Salvatierra, Juanpablo; Wideman, Ronney

    2015-04-01

    Laurel wilt, caused by Raffaelea lauricola, is a destructive disease of avocado (Persea americana). The susceptibility of different cultivars and races was examined previously but more information is needed on how this host responds to the disease. In the present study, net CO2 assimilation (A), stomatal conductance of H2O (gs), transpiration (E), water use efficiency (WUE), and xylem sap flow rates were assessed in cultivars that differed in susceptibility. After artificial inoculation with R. lauricola, there was a close relationship between symptom development and reductions in A, gs, E, WUE, and mean daily sap flow in the most susceptible cultivar, 'Russell', and significantly greater disease and lower A, gs, E, WUE, and sap flow rates were usually detected after 15 days compared with the more tolerant 'Brogdon' and 'Marcus Pumpkin'. Significant differences in preinoculation A, gs, E, and WUE were generally not detected among the cultivars but preinoculation sap flow rates were greater in Russell than in Brogdon and Marcus Pumpkin. Preinoculation sap flow rates and symptom severity for individual trees were correlated at the end of an experiment (r=0.46), indicating that a plant's susceptibility to laurel wilt was related to its ability to conduct water. The potential management of this disease with clonal rootstocks that reduce sap flow rates is discussed.

  7. Detection and Differentiation between Laurel Wilt Disease, Phytophthora Disease, and Salinity Damage Using a Hyperspectral Sensing Technique

    Directory of Open Access Journals (Sweden)

    Jaafar Abdulridha

    2016-10-01

    Full Text Available Laurel wilt (Lw is a fatal disease. It is a vascular pathogen and is considered a major threat to the avocado industry in Florida. Many of the symptoms of Lw resemble those that are caused by other diseases or stress factors. In this study, the best wavelengths with which to discriminate plants affected by Lw from stress factors were determined and classified. Visible-near infrared (400–950 nm spectral data from healthy trees and those with Lw, Phytophthora, or salinity damage were collected using a handheld spectroradiometer. The total number of wavelengths was averaged in two ranges: 10 nm and 40 nm. Three classification methods, stepwise discriminant (STEPDISC analysis, multilayer perceptron (MLP, and radial basis function (RBF, were applied in the early stage of Lw infestation. The classification results obtained for MLP, with percent accuracy of classification as high as 98% were better than STEPDISC and RBF. The MLP neural network selected certain wavelengths that were crucial for correctly classifying healthy trees from those with stress trees. The results showed that there were sufficient spectral differences between laurel wilt, healthy trees, and trees that have other diseases; therefore, a remote sensing technique could diagnose Lw in the early stage of infestation.

  8. A novel, sensitive method to evaluate potato germplasm for bacterial wilt resistance using a luminescent Ralstonia solanacearum reporter strain.

    Science.gov (United States)

    Cruz, Andrea Paola Zuluaga; Ferreira, Virginia; Pianzzola, María Julia; Siri, María Inés; Coll, Núria S; Valls, Marc

    2014-03-01

    Several breeding programs are under way to introduce resistance to bacterial wilt caused by Ralstonia solanacearum in solanaceous crops. The lack of screening methods allowing easy measurement of pathogen colonization and the inability to detect latent (i.e., symptomless) infections are major limitations when evaluating resistance to this disease in plant germplasm. We describe a new method to study the interaction between R. solanacearum and potato germplasm that overcomes these restrictions. The R. solanacearum UY031 was genetically modified to constitutively generate light from a synthetic luxCDABE operon stably inserted in its chromosome. Colonization of this reporter strain on different potato accessions was followed using life imaging. Bacterial detection in planta by this nondisruptive system correlated with the development of wilting symptoms. In addition, we demonstrated that quantitative detection of the recombinant strain using a luminometer can identify latent infections on symptomless potato plants. We have developed a novel, unsophisticated, and accurate method for high-throughput evaluation of pathogen colonization in plant populations. We applied this method to compare the behavior of potato accessions with contrasting resistance to R. solanacearum. This new system will be especially useful to detect latency in symptomless parental lines before their inclusion in long-term breeding programs for disease resistance.

  9. Evaluation of the gene encoding the enzyme βHPMEH for the bacterial wilt inhibition caused by Ralstonia solanacearum

    Directory of Open Access Journals (Sweden)

    Elizabeth Fernandez

    2015-10-01

    Full Text Available Ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease that attacks important agricultural crops such as potato, tomato, banana, among others, causing serious yield losses. Control of R. solanacearum is difficult because of its wide range of alternate hosts, its long survival in soil, its biological and genetic variation, the lack of natural resistance sources and the insufficiency of the appropriate chemical control measures. Quorum sensing is the term that describes the phenomenon whereby the accumulation of molecules allows bacteria to know the number of bacteria found in the environment (population density. R. solanacearum has a quorum sensing system for the regulation of the expression of virulence genes; the molecule 3-OH-PAME is the self-regulatory signal. The molecule ΒHPMEH hydrolyzes 3-OH-PAME nullifying the signal of virulence, and thus, the quorum sensing communication in R. solanacearum. In order to evaluate the βhpmeh gene we designed two vectors that express this gene under the control of two different promoters. Both vectors were verified by restriction analysis and sequencing. Agroinfiltration assays were used to analyze gene expression and the effect against R. solanacearum in potato (Solanum tuberosum leaves. The results of the transient expression experiments showed that the expression of gene βhpmeh caused a delay in the appearance of symptoms of bacterial wilt and thus is a good candidate for whole genetic plant transformation.

  10. Registration of five pima cotton germplasm lines (SJ-FR05 - FR09) with improved resistance to fusarium wilt race 4 and good lint yield and fiber quality

    Science.gov (United States)

    Cotton breeders continue to need alternative sources of cotton breeding lines for improving Fusarium wilt (FOV race 4) resistance in Pima cotton in California. FOV race 4 is a fungus that has impacted cotton yields in the San Joaquin Valley (SJV) for the last 12 years. For this purpose, the Agricult...

  11. Dynamics of Colonization and Expression of Pathogenicity Related Genes in Fusarium oxysporum f.sp. ciceri during Chickpea Vascular Wilt Disease Progression.

    Science.gov (United States)

    Upasani, Medha L; Gurjar, Gayatri S; Kadoo, Narendra Y; Gupta, Vidya S

    2016-01-01

    Fusarium wilt caused by Fusarium oxysporum f.sp. ciceri (Foc) is a constant threat to chickpea productivity in several parts of the world. Understanding the molecular basis of chickpea-Foc interaction is necessary to improve chickpea resistance to Foc and thereby the productivity of chickpea. We transformed Foc race 2 using green fluorescent protein (GFP) gene and used it to characterize pathogen progression and colonization in wilt-susceptible (JG62) and wilt-resistant (Digvijay) chickpea cultivars using confocal microscopy. We also employed quantitative PCR (qPCR) to estimate the pathogen load and progression across various tissues of both the chickpea cultivars during the course of the disease. Additionally, the expression of several candidate pathogen virulence genes was analyzed using quantitative reverse transcriptase PCR (qRT-PCR), which showed their characteristic expression in wilt-susceptible and resistant chickpea cultivars. Our results suggest that the pathogen colonizes the susceptible cultivar defeating its defense; however, albeit its entry in the resistant plant, further proliferation is severely restricted providing an evidence of efficient defense mechanism in the resistant chickpea cultivar.

  12. Thrips resistance in pepper and its consequences for the acquisition and inoculation of Tomato spotted wilt virus by the Western Flower Thrips

    NARCIS (Netherlands)

    Maris, P.C.; Joosten, N.N.; Peters, D.; Goldbach, R.W.

    2003-01-01

    Different levels of thrips resistance were found in seven Capsicum accessions. Based on the level of feeding damage, host preference, and host suitability for reproduction, a thrips susceptible and a resistant accession were selected to study their performance as Tomato spotted wilt virus (TSWV)

  13. Effects of different soil amendments on bacterial wilt caused by Ralstonia solanacearum (Smith) Yabuuchi and on the yield of tomato (Lycopersicon esculentum Mill)

    NARCIS (Netherlands)

    Yadessa, G.B.; Bruggen, van A.H.C.; Ocho, F.L.

    2010-01-01

    Ralstonia solanacearum race 3 biovar 2 (phylotype II) is the causal agent of bacterial wilt of tomato, the most destructive bacterial disease of this crop in Ethiopia for which no effective control measures are available. In this study, the effects of amending topsoil with three different levels (1,

  14. Draft genome sequence of the fungus associated with oak-wilt mortality in South Korea, Raffaelea quercus-mongolicae KACC44405

    Science.gov (United States)

    Jongbum Jeon; Ki-Tae Kim; Hyeunjeong Song; Gir-Won Lee; Kyeongchae Cheong; Hyunbin Kim; Gobong Choi; Yong-Hwan Lee; Jane E. Stewart; Ned B. Klopfenstein; Mee-Sook Kim

    2017-01-01

    The fungus Raffaelea quercus-mongolicae is the causal agent of Korean oak wilt, a disease associated with mass mortality of oak trees (e.g., Quercus spp.). The fungus is vectored and dispersed by the ambrosia beetle, Platypus koryoensis. Here, we present the 27.0-Mb draft genome sequence of R. quercus-mongolicae strain KACC44405.

  15. First report of Fusarium decemcellulare causing inflorescence wilt, vascular and flower necrosis of rambutan (Nephelium lappaceum), longan (Dimocarpus longan) and mango (Mangifera indica)

    Science.gov (United States)

    Longan, mango and rambutan are very important fruit crops in Puerto Rico. During a disease survey in Puerto Rico conducted from 2008 to 2010, 50% of the inflorescences were affected with inflorescence wilt, flower and vascular necrosis at 70% of the fields of rambutan and longan at the USDA-ARS Rese...

  16. An Ophiostoma sp. causing a vascular wilt disease of red bay (Persea borbonia [L.] Spreng) is also pathogenic to other species in the Lauraceae family

    Science.gov (United States)

    Stephen Fraedrich

    2007-01-01

    Extensive mortality of red bay (Persea borbonia [L.] Spreng) has been observed in the coastal plains of South Carolina and Georgia since 2003. Dead and dying trees exhibit wilt-like symptoms, and a fungus (an Ophiostoma sp.) and an exotic ambrosia beetle (Xyleborus glabratus [Eichhoff]) have been implicated in...

  17. Immunofluorescence localization and ultrastructure of Stewart’s wilt disease bacterium Pantoea stewartii in maize leaves and in its flea beetle vector Chaetocnema pulicaria (Coleoptera: Chrysomelidae)

    Science.gov (United States)

    Pantoea stewartii is the causal agent of Stewart's wilt of sweet corn, the most serious bacterial disease of sweet corn and maize in the North-Central and Eastern USA. P. stewartii is transmitted mainly by the corn flea beetle Chaetocnema pulicaria (Coleoptera: Chrysomelidae) and this bacterium is a...

  18. Application of phage display in selecting Tomato spotted wilt virus - specific single-chain antibodies (scFvs) for sensitive diagnosis in ELISA

    NARCIS (Netherlands)

    Griep, R.A.; Prins, M.; Twisk, van C.; Keller, H.J.H.G.; Kerschbaumer, R.J.; Kormelink, R.; Goldbach, R.W.; Schots, A.

    2000-01-01

    A panel of recombinant single-chain antibodies (scFvs) against structural proteins of Tomato spotted wilt virus (TSWV) was retrieved from a human combinatorial scFv antibody library using the novel phage display technique. After subcloning the encoding DNA sequences in the expression vector pSKAP/S,

  19. Entomopathogenic fungi as a biological control agents for the vector of the laurel wilt disease, the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae)

    Science.gov (United States)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...

  20. Evaluation of commercial formulations of entomopathogenic fungi to manage the redbay ambrosia beetle, vector of Laurel wilt, a lethal disease affecting avocados in Florida

    Science.gov (United States)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...