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Sample records for tridentatacontra rhizoctonia solanien

  1. Rhizoctonia Brown Patch Introduction

    E-print Network

    New Hampshire, University of

    Rhizoctonia Brown Patch Turf Pest Fact Sheet 44 Introduction Rhizoctonia brown patch is a common fungal disease of all turf grasses. It develops most readily at temperatures between 80-850 F. On taller turf (e.g., on home lawns, park lawns, and golf course fairways), the diseased areas range from 2

  2. Rhizoctonia root rot of lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot is a soilborne disease of lentil caused by the fungal pathogen Rhizoctonia solani, and is favored by cool (11-19 C or 52 - 66 F) and wet soil conditions. The disease starts as reddish or dark brown lesions on lentil plants near the soil line, and develops into sunken lesions an...

  3. Rhizoctonia web blight on azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, fungicides are the only useful control for azalea web blight, but fungicides do not eliminate the pathogen. We have discovered that Rhizoctonia colonizes the entire azalea plant 12 months of the year in the Gulf Coast climate. This results in healthy appearing stems collected for propagat...

  4. Depth at which Rhizoctonia solani causes infection fo sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani (Kuhn) is the causal agent of Rhizoctonia root rot of sugar beet (Beta vulgaris L.). Typically, Rhizoctonia root rot symptoms appear to be initiated on the plant at the soil line. Recently, sugar beet plants were observed with Rhizoctonia root rot infections close to the root ti...

  5. In vitro fungicide sensitivity of Rhizoctonia isolates collected from turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different Rhizoctonia species and anastomosis groups (AGs) have been reported to show variable sensitivity to various commercial fungicides. Thirty–six isolates of Rhizoctonia collected from turfgrasses were tested in vitro for sensitivity to commercial formulations of iprodione, triticonazole, and ...

  6. Reduction of Rhizoctonia bare patch win wheat with barley rotations.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia bare patch caused by Rhizoctonia solani AG-8 is a major fungal root disease in no-till cropping systems. In an 8-year experiment comparing various dryland no-till cropping systems near Ritzville, Washington, Rhizoctonia bare patch first appeared in year 3 and continued through year 8. ...

  7. EMS-generated Rhizoctonia resistance in an adapted wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the first genetic resistance in wheat to Rhizoctonia solani AG-8 and R. oryzae, the causal agents of Rhizoctonia root rot and pre-emergence damping-off. Rhizoctonia resistance was generated in the spring wheat cultivar Scarlet using EMS mutagenesis. Resistant plants, named Scarlet-Rz1, d...

  8. Management of Rhizoctonia root and crown rot of subarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root and crown rot is caused by the fungus Rhizoctonia solani and is one of the most severe soil-borne diseases of sugarbeet in Minnesota and North Dakota. Rhizoctonia root and crown rot may reduce yield significantly, and diseased beets may cause problems in storage piles. Fields with...

  9. Research on Rhizoctonia Web Blight on Azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 ‘Gumpo’ azalea plants. Plant ...

  10. Rhizoctonia seed, seedling, and wet root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wet root rot caused by Rhizoctonia solani Kühn can cause seed and seedling rot of both lentil and chickpea as well as many other agricultural crops worldwide. The pathogen is favored in cool, sandy soil with high organic matter under no-till or reduced-till soil management practices. Survival spor...

  11. DOUBLE-STRANDED RNA-MEDIATED HYPOVIRULENCE OF RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is a soilborne fungal plant pathogen responsible for economic losses of crops worldwide. Isolates of Rhizoctonia (anastomosis group 3) cause a disease commonly known as black scurf, stem and stolon canker of potato. We observed that some isolates of the pathogen lose their ability...

  12. Rhizoctonia-Bacterial Root Rot Complex in Sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rhizoctonia-bacterial root rot complex is a disease problem of concern worldwide in sugarbeet. A series of studies have been conducted which indicate that the complex is initiated by the fungal pathogen, Rhizoctonia solani. However, only about 6% of the root mass is lost to the fungal infectio...

  13. The effect of temperature on Rhizoctonia disease development and fungicide efficacy in controlling Rhizoctonia root rot on sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 2-2 is the causal agent of Rhizoctonia root and crown rot in sugarbeet. Since the intraspecific group AG 2-2 IIIB is considered to be more virulent than AG 2-2 IV, our objectives were to monitor disease development of AG 2-2 IIIB infection at four different soil temperatures un...

  14. The effect of temperature on Rhizoctonia disease development and fungicide efficacy in controlling Rhizoctonia root rot on sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 2-2 is the causal agent of Rhizoctonia root and crown rot in sugarbeet. This disease has recently been increasing in occurrence and severity in sugarbeet production areas in the Red River Valley of Minnesota and North Dakota. Since the intraspecific groups AG 2-2 IIIB and AG 2-...

  15. The prevalence of different strains of Rhizoctonia solani associated with Rhizoctonia crown and root rot symptoms in Ontario sugarbeet fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown and root rot (RCRR) [Rhizoctonia solani Kühn] is an important disease of sugarbeets in southwestern Ontario, Canada. A survey of commercial sugarbeet fields was completed in 2010 and 2011 to determine the range of R. solani anastomosis groups (AGs) and inter-specific groups (ISGs) ...

  16. SPATIAL DISTRIBUTION OF RHIZOCTONIA ORYZAE AND RHIZOCTONIA ROOT ROT IN DIRECT-SEEDED CEREALS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia oryzae causes root rot and stunting of wheat, barley, and other small grains, and is widely distributed in eastern Washington. The spatial distribution of both the pathogen and disease were studied over two seasons in a 36-ha field north of Pullman, WA. The field was direct-seeded with s...

  17. Rhizoctonia belly rot in cucumber fruit using Rhizoctonia solani isolated from sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucumbers are grown in rotation with sugar beets in some areas in Michigan but their interaction with important diseases affecting sugar beets is not well known. Cucumbers are known to be primarily susceptible to Rhizoctonia solani AG-4, but little is known about their susceptibility to AG 2-2 isola...

  18. Effect of pH on the growth of Rhizoctonia spp. from cereal-based cropping systems in eastern Washington State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot caused by Rhizoctonia solani AG 8 and Rhizoctonia oryzae are serious root diseases in dryland cereal production in Washington State. Isolates of Rhizoctonia spp. from fields with different cropping histories in the low- (12 inches) precipitation zones...

  19. Evaluation of strategies for the control of canola and lupin seedling diseases caused by Rhizoctonia anastomosis groups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several methods with potential for the management of Rhizoctonia diseases of canola and lupin including several methods with potential for the management of Rhizoctonia plant resistance, fungicide seed treatment and biological control using binucleate Rhizoctonia anastomosis groups (AGs) were evalua...

  20. Optimized protein extraction methods for proteomic analysis of Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani (Teleomorph: Thanatephorus cucumeris) is a basidiomycetous fungus which includes important plant pathogens, saprophytes and mycorrhizae. R. solani displays several hyphal anastomosis groups (AGs) with distinct host plant specializations. In order to facilitate studies on its biol...

  1. AFLP fingerprinting for identification of infra-species groups of Rhizoctonia solani and Waitea circinata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Patch diseases caused by Thanatephorus cucumeris and Waitea circinata varieties (anamorphs: Rhizoctonia species) pose a serious threat to successful maintenance of several important turfgrass species. Reliance on field symptoms to identify Rhizoctonia causal agents can be difficult and misleading. D...

  2. Optimum Timing of Pre-Plant Applications of Glyphosate to Manage Rhizoctonia Root Rot in Barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot, caused by Rhizoctonia solani AG-8 and R. oryzae, is considered one of the main deterrents for farmers to adopt reduced tillage systems in the Pacific Northwest. Because of the wide host range of Rhizoctonia spp., herbicide application before planting to control weeds and volunt...

  3. Virulence, distribution and diversity of rhizoctonia solani from sugar beet in Idaho and Oregon.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot causes serious losses on sugar beet worldwide. In order to help explain why Rhizoctonia root rot management practices have not performed well in some areas of the Intermountain West (IMW), a survey was conducted. In the IMW from 2004 to 2006, 94 Rhizoctonia solani field isolat...

  4. GENETIC DIVERSITY AND VIRULENCE OF RHIZOCTONIA SPECIES ASSOCIATED WITH PLANTINGS OF LOTUS CORNICULATUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species of Rhizoctonia cause a blight of Lotus corniculatus, a perennial forage legume. We characterized genetic variation and virulence in populations of Rhizoctonia solani and binucleate Rhizoctonia associated with diseased L. corniculatus in field plantings over a period of several years. Isola...

  5. Biogenesis of pipecolic acid in Rhizoctonia leguminicola

    SciTech Connect

    Wickwire, B.M.

    1989-01-01

    This laboratory has long been interested in the biogenesis and biological properties of two indolizidine alkaloids, slaframine and swainsonine that are produced by the fungal parasite Rhizoctonia Leguminicola. Slaframine, (1S,6S,8aS-1 acetoxy-6-aminooctahydroindolizine) is a parasympathetic secretagogue, and swainsonine (1S,2R,8R,8aR-1,2,8-trihydroxyoctahydroindolizine) is a potent {alpha}-mannosidase inhibitor. This thesis concerns the initial steps of the biosynthesis of these alkaloids from lysine, via the common intermediate pipecolic acid, in whole cells and cell free enzyme systems of R. leguminicola. In confirmation of earlier work performed in this laboratory, L-lysine was used preferentially for pipecolate biosynthesis in R. Leguminicola. This pathway was supported by the finding that cell free extracts of R. leguminicola consistently converted L-(U-{sup 14}C)-lysine to three labelled metabolites: saccharopine, peak II, and pipecolic acid. Peak II was subsequently identified by appropriate proton NMR studies to be {delta}{sup 1}-piperideine-6-carboxylate, and the following pathway of pipecolic acid formation was postulated: L-lysine {yields} saccharopine {yields} {delta}{sup 1}-piperideine-6-carboxylate {yields} pipecolate. This pathway was confirmed by demonstration of each enzymatic step in vitro from purified radiolabeled substrates.

  6. Signaling in the Rhizoctonia solani-rice pathosystem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is a necrotrophic soil borne fungal pathogen known to be a serious crop killer worldwide. A better understanding of the molecular signaling will benefit the development of effective methods to control the pathogen. To dissect molecular signaling between rice and R. solani a combin...

  7. Propagating azalea stem cuttings free of binculeate Rhizoctonia spp

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight, caused by binucleate species of Rhizoctonia (BNR), occurs yearly on some azalea cultivars during nursery production in the U.S. Azalea shoots collected for cutting propagation can harbor the pathogen, thus allowing the disease to be perpetuated. Previous studies have demonstrated ...

  8. HOST-PATHOGEN INTERACTION OF SUGARBEET SEEDLINGS WITH RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The progress curve of seedling damping-off caused by Rhizoctonia solani showed three distinct stages - an initial rapid disease progress stage, an intermediate stationary phase, and a final decline and death phase, in the compatible interaction. Both virulent and avirulent fungal isolates initiated ...

  9. Rhizoctonia damping-off stem canker and root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani has been reported to cause damping-off and root rot of rhododendrons and azaleas. Damping-off often includes groups of dying and dead seedlings. Decline of rooted plants in containers results from both root rot and stem necrosis below or above the soil line. Root rot is usually no...

  10. Influence of glyphosate on Rhizoctonia crown and root rot (Rhizoctonia solani) in glyphosate-resistant sugarbeet (Beta vulgaris L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous greenhouse studies with a non-commercial glyphosate-resistant sugarbeet variety indicated that susceptibility to Rhizoctonia crown and root rot could increase after glyphosate was applied. Greenhouse and field experiments were conducted in 2008 and 2009 to determine if glyphosate influenced...

  11. Survey of Rhizoctonia spp. from wheat soils in the U.S. and determination of pathogenicity on wheat and barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot and bare patch are chronic diseases of wheat and barley in the Pacific Northwest (PNW), but little is known about Rhizoctonia spp. in other cereal growing areas of the U.S. A survey was conducted in the fall of 2009 and 2010 to identify Rhizoctonia spp. from soils collected thro...

  12. RHIZOCTONIA ROOT ROT RESISTANCE OF BETA PIS FROM THE USDA ARS NPGS, 2002.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Rhizoctonia root rot. Materials were planted at the Crops Research Lab-Fort Collins Research Farm in CO and inoculated with dry, ground, barley-grain inoculum of Rhizoctonia...

  13. Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugar beet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani AG 2-2, is a common root disease on sugar beet that reduces yield and sucrose during the growing season and causes further losses by increasing respiration and reducing sucrose content during storage. The industry needs to identify...

  14. Management of Rhizoctonia Damping-off of Brassica Oilseed Crops in the PNW

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani can cause pre and post-emergence damping off of Brassica oilseed species with adverse effects on stand establishment. In greenhouse experiments, we have examined resistance to two groups (AGs) of Rhizoctonia solani among various Brassica species and varieties. R. solani AG 2-1 is ...

  15. Temperature, Moisture, and Fungicide Effects in Managing Rhizoctonia Root and Crown Rot of Sugar Beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG-2-2 is the causal agent of Rhizoctonia root and crown rot in sugar beet. To assess the capacity at which other anastomosis groups (AGs) are able to infect sugar beet, 15 AGs and subgroups were tested for pathogenicity on resistant (FC708 CMS) and susceptible (Monohikari) seedl...

  16. Risk of Rhizoctonia Web Blight Development on Container-Grown Azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight, caused by binucleate Rhizoctonia spp., is an annual problem in the southern United States on container-grown azaleas (Rhododendron spp.) that receive daily irrigation. Disease progress was assessed weekly from mid-May to early October in blocks of nursery-grown plants at four...

  17. Characterization of Rhizoctonia isolates associated with damping-off and crown rot of rooibos seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia species were reported to be an important component of the complex involved in damping-off of rooibos (Aspalathus linearis) seedlings and cause severe crown rot of seedlings in nurseries. However, no information is available on the anastomosis groups (AGs) of Rhizoctonia associated with d...

  18. Rhizoctonia Species Associated With Bark Media and Plant Strata of Container-Grown Azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Symptoms of Rhizoctonia web blight, caused predominantly by binucleate Rhizoctonia (BNR) anastomosis group U, develops annually from late-June to mid-September on container-grown azaleas (Rhododendron spp.) in the southern United States. In 2005 and 2006, ‘Gumpo White’ azalea plants with a disease ...

  19. RHIZOCTONIA ROOT ROT RISISTANCE OF BETA PIS FROM THE USDA-ARS NPGS, 2001

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Rhizoctonia root rot. Materials were planted at the Crops Research Lab-Fort Collins Research Farm in CO and inoculated with dry, ground, barley-grain inoculum of Rhizoctonia solani i...

  20. Preparation on Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown root and rot, caused by Rhizoctonia solani Kühn, is a serious disease resulting in substantial economic losses in sugar beet production worldwide. A consistent, uniform disease pressure of the correct intensity is necessary to effectively screen sugar beet for resistance to Rhizoc...

  1. Interaction of sugarbeet host resistance and Rhizoctonia solani AG-2-2 IIIB strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rhizoctonia root rot caused by Rhizoctonia solani can cause serious economic losses in sugarbeet fields. Preliminary evidence suggests there could be interactions between different strains and resistance sources. Thus, field studies were conducted to determine if nine R. solani AG-2-2 IIIB str...

  2. Pathogenicity of three isolates of Rhizoctonia sp. from wheat and peanut on hard red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia-induced root diseases can significantly affect wheat and peanut production where these two field crops are grown in rotation. Hence, this study characterized two isolates of Rhizoctonia spp. from wheat [R. cerealis (RC) and R. solani (RSW)] and one from peanut [R. solani (RSP) ] for cul...

  3. Rapid quantitative assessment of Rhizoctonia tolerance in roots of wheat and barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG8, causal agent of Rhizoctonia root rot and bare patch in dryland cereal production systems of the Pacific Northwest, USA and Australia, reduces yields in a wide range of crops. Disease is not consistently controlled by available management practices, and genetic resistance is d...

  4. Agroecological factors correlated to Rhizoctonia spp. in dryland wheat production zones of Washington state, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The necrotrophic soilborne fungal pathogens Rhizoctonia solani AG8 and R. oryzae are principal causal agents of Rhizoctonia root rot of wheat in dryland cropping systems of the Pacific Northwest (PNW). A three-year survey of 33 parcels at eleven growers’ sites and 22 plots at twelve Washington State...

  5. Influence of tillage systems on Rhizoctonia-bacterial root rot complex in sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...

  6. Rhizoctonia root rot resistance in commercial sugar beet cultivars in Twin Falls County, ID, 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 commercial sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface ro...

  7. Rhizoctonia root rot resistance of Beta PIs from the USDA-ARS NPGS, 2006.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Rhizoctonia root rot. Materials were planted at the Crops Research Lab-Fort Collins Research Farm in CO and inoculated with dry, ground, barley-grain inoculum of Rhizoctonia solani is...

  8. Timing and Methodology of Application of Azoxystrobin to Control Rhizoctonia Solani in Sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 2-2 is the causal agent of Rhizoctonia root and crown rot of sugar beet (Beta vulgaris) in North Dakota and Minnesota. This disease is a major limiting factor to sugar beet production. Management strategies currently include using partially resistant cultivars and fungicides. ...

  9. Interaction of Rhizoctonia solani and Rhizopus stolonifer Causing Root Rot of Sugar Beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, growers in Michigan and other sugar beet production areas of the United States have reported increasing incidence of root rot with little or no crown or foliar symptoms in sugar beet with Rhizoctonia crown and root rot. In addition, Rhizoctonia-resistant beets have been reported wit...

  10. Interaction between Meloidogyne incognita and Rhizoctonia solani on green beans

    PubMed Central

    Al-Hazmi, A.S.; Al-Nadary, S.N.

    2015-01-01

    The interaction between Meloidogyne incognita (race 2) and Rhizoctonia solani (AG 4) in a root rot disease complex of green beans (Phaseolus vulgaris) was examined in a greenhouse pot experiment. Three week-old seedlings (cv. Contender) were inoculated with the nematode and/or the fungus in different combinations and sequences. Two months after last nematode inoculation, the test was terminated and data were recorded. The synchronized inoculation by both pathogens (N + F) increased the index of Rhizoctonia root rot and the number of root galls; and suppressed plant growth, compared to controls. However, the severity of root rot and suppression of plant growth were greater and more evident when inoculation by the nematode preceded the fungus (N ? F) by two weeks. Nematode reproduction (eggs/g root) was adversely affected by the presence of the fungus except by the synchronized inoculation. When inoculation by nematode preceded the fungus, plant growth was severely suppressed and roots were highly damaged and rotted leading to a decrease of root galls and eggs. PMID:26288560

  11. SCREENING AND CHARACTERIZATION OF STREPTOMYCES ISOLATES FOR BIOCONTROL OF RHIZOCTONIA SOLANI AND OTHER PLANT PATHOGENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani, a ubiquitous soilborne fungal plant pathogen, is responsible for economic losses of agricultural, forestry, horticultural and ornamental crops worldwide. Soil actinomycetes are known to enhance fertility and possess antimicrobial properties against various plant pathogens. One hu...

  12. Transgenic expression of Lactoferrin imparts resistance to a soilborne fungal pathogen Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic tobacco (Nicotiana tabacum var Xanthi) and Arabidopsis (A. thaliana) plants expressing an antimicrobial bovine lactoferrin (BLF) gene were developed and evaluated for resistance against an economically important fungal pathogen Rhizoctonia solani, the causal agent of damping off diseases....

  13. DNA fingerprinting and anastomosis grouping reveal similar genetic diversity in Rhizoctonia species infecting turfgrasses in the transition zone of USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia blight (sensu lato) is a common and serious disease of many turfgrass species. The most widespread causal agent, R. solani, consists of several genetically different subpopulations. Though hyphal anastomosis reactions have been used to group Rhizoctonia species, they are time consuming a...

  14. Rhizoctonia anastomosis groups associated with diseased rooibos seedlings and the potential of compost as soil amendment for disease suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia spp. associated with rooibos in the Western Cape province of South Africa were recovered during the 2008 season by planting seedlings in rhizosphere soils collected from 14 rooibos nurseries. Seventy five Rhizoctonia isolates were obtained and 67 were multinucleate and 8 binucleate Rhiz...

  15. Screening of a dry bean Andean diversity panel for potential sources of resistance to Rhizoctonia crown and root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani, is a major problem in most sugar beet production areas and can cause substantial losses in both yield and quality. Over the last decade, it has become the most prevalent root disease of sugar beet in Michigan and several other regi...

  16. First evidence of a binucleate Rhizoctonia as the causal agent of dry rot canker of sugar beet in Nebraska, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar beet (Beta vulgaris L.) is the primary source of domestic sucrose in the United States. In 2011, a sugar beet field in Morrill County NE was noted with wilting and yellowing symptoms suggestive of Rhizoctonia root and crown rot (RCRR), an important disease of sugar beet caused by Rhizoctonia s...

  17. Screening Sugar Beet Germplasm for Resistance to Rhizoctonia solani in Artifically Induced Field Epiphytotics: Examining 25 Years of Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot (caused by the fungus Rhizoctonia solani Kühn, AG2-2) continues to be a problem in most sugar beet-growing areas in the United States, and is a growing problem worldwide. The USDA-ARS at Fort Collins has screened germplasm in artificially induced epiphytotics to provide uniform...

  18. Management of Rhizoctonia Root Rot of Sugarbeet - Fungicide Efficacy and Identification of Environmental Parameters for Disease Development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 2-2 is the causal agent of Rhizoctonia root and crown rot in sugarbeet. This disease has recently been increasing in occurrence and severity in sugarbeet production areas in the Red River Valley of Minnesota and North Dakota. Since the intraspecific groups AG 2-2 IIIB and AG 2-...

  19. Evaluation of Beta PIs from the USDA-ARS, NPGS for Rhizoctonia crown and root rot resistance, 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty sea beet (Beta vulgaris subsp. maritima (L.) Arcang accessions from the Beta collection of the USDA-ARS National Plant Germplasm System were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. The Rhizoctonia screening nursery in 2013 wa...

  20. Long Term Preservation of a Collection of Rhizoctonia Solani, using Cryogenic Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Rhizoctonia solani Kühn is an important plant pathogen on a number of crops and maintaining an extensive collection of reference isolates is important in understanding relationships of this pathogen with multiple hosts. While a number of long-term storage methods have been developed, mos...

  1. Long-term Preservation of a Collection of Rhizoctonia solani, using Cryogenic Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is an important plant pathogen on a number of crops and maintaining an extensive collection of reference isolates is important in understanding relationships of this pathogen with multiple hosts. Current long-term storage methods typically call for frequent transfer increasing the...

  2. Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizotonia crown and root rot of sugarbeet, caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. The objective of th...

  3. Rhizoctonia in Container Grown Azalea, and Camellia Twig Blight: Incubation and Latency Periods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. Disease severity was measured weekly in ‘Gumpo’ azalea plants spaced at distances of 0, 6, 12, 18, or 24 cm. Evaporative potential (EP), leaf wetness (LW), rela...

  4. Effect of Plant Spacing on Microclimate and Rhizoctonia Web Blight Development in Container Grown Azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 ‘Gumpo’ azalea plants. Plant ...

  5. Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugarbeet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The negative impact of Rhizoctonia crown and root rot (RCRR) on postharvest respiration, sugar concentration, and beet quality for roots with disease ratings of 2 or 3 is relatively small and would have only a small, and maybe immeasurable, effect on factory efficiency when mixed with healthy roots....

  6. Spread potential of binucleate Rhizoctonia from propagation floors to trays containing stem cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Binucelate Rhizoctonia spp. (BNR), the cause of web blight, are present all year on container-grown azaleas in the southern U.S. BNR can be eliminated during vegetative propagation by submerging stem cuttings in 50°C water for 21 minutes. The objective was to evaluate risk of rooting trays bein...

  7. RL-SAGE and microarray analysis of the rice defense transcriptome after Rhizoctonia solani infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, RNA isolated from R. solani-infected leaves of Jasmine 85 was used for both RL-SAGE library construction and microarra...

  8. RESPONSE OF COWPEA CULTIVARS TO RHIZOCTONIA SOLANI IN FIELD TESTS AT FOUR PLANTING DATES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is an important pathogen of cowpea (Vigna unguiculata) in the southern U.S. and is the primary cause of seedling diseases in this crop. Stand losses caused by R. solani are especially severe when cowpea is planted in cold, spring soils. Three cowpea cultivars (Coronet, Knuckle P...

  9. Distribution of Rhizoctonia Bare Patch and Root Rot in Eastern Washington and Relation to Climatic Variables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia is a fungus that attacks the roots of wheat and barley, causing a root rot and bare patch in the dryland wheat cropping area of the inland Pacific Northwest. Over the last 7 years, we have been investigating the distribution of this pathogen, using molecular methods based on extracting a...

  10. Comparative analysis of putative pathogenesis-related gene expression in two Rhizoctonia solani pathosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani, teleomorph Thanatephoris cucumeris, is a polyphagous nectrotrophic plant pathogen of the Basidiomycete order that is split into fourteen different anastomosis groups (AGs) based on hyphal interactions and host range. Currently, little is known about the methods by which R. solan...

  11. Genetic characterization of binucleate Rhizoctonia species causing web blight on azelea in Mississippi and Alabama

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Web blight on containerized azalea is an annual problem for commercial nurseries during the summer months in the southern US. Losses to web blight are associated with the cost of fungicides, delayed marketing of diseased plants, and plant death. Three hundred and nine isolates of Rhizoctonia recover...

  12. MOLECULAR AND PATHOLOGICAL CHARACTERIZATION OF THE RICE SHEATH BLIGHT PATHOGEN RHIZOCTONIA SOLANI IN ARKANSAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani (AG1-IA), is an economically important disease in Arkansas. To identify the sheath blight resistance gene(s) an extensive molecular and pathological characterization of R., solani was initiated. A wide range of pathogen isolates ...

  13. Influence of Rhizoctonia-Bacterial root rot complex on storability of sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The root rot complex, caused by Rhizoctonia solani and Leuconostoc mesenteroides, can lead to yield loss in the field but may also lead to problems with sucrose loss in storage. Thus, studies were conducted to investigate if placing sugar beet roots suffering from root rot together with healthy roo...

  14. CHARACTERIZATION OF SHEATH BLIGHT PATHOGEN RHIZOCTONIA SOLANI AND ITS MOLECULAR INTERACTION WITH ORYZA SATIVA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: Little is known about mechanisms of molecular interaction of hosts with the necrotrophic pathogen Rhizoctonia solani. Detailed analysis of the pathogen population in Arkansas, the major rice producing state in the USA, led to the identification of the most virulent field isolate out of a...

  15. NEW SOURCES OF RESISTANCE IN COWPEA (VIGNA UNGUICULATA) TO RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is an important pathogen of cowpea (Vigna unguiculata) seedlings causing substantial yield losses worldwide. Fungicide seed treatments are the current method of control for cowpea seedling diseases. The use of resistant cultivars would provide an improved control measure over cu...

  16. Comparison of bacterial communities from inside and outside of Rhizoctonia bare patches in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG-8 causes distinct patches of stunted wheat in the field. Bacterial communities from bulk soil and rhizospheres of wheat were analyzed with pyrosequencing. Replicated samples were taken from inside and outside of patches; and from patches that had recovered the previous 1–2 year...

  17. Development of an Agrobacterium-based transformation system for Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 8.7 kb binary vector containing the 1.9 kb hygromycin B phosphortransferase (hyg) gene was constructed with promoter and terminator regions from the glyceraldehyde-3-phosphate- dehydrogenase (gpd) gene of Rhizoctonia solani anastomosis group 3 (AG-3) at the 5'- and 3'- gene termini of hyg. Promot...

  18. Rhizoctonia root rot resistance of Beta PIs from the USDA-ARS NPGS, 2007.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-two plant introductions (PI) from the USDA-ARS National Plant Germplasm System (NPGS) (including garden beet, sugar beet, leaf beet, fodder beet, and wild beet) were evaluated for resistance to Rhizoctonia root rot. The trial was a randomized complete-block design with five replications in ...

  19. Rhizoctonia Resistant Wheat -- Potential New Resources for Control for Soilborne Pathogens.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pacific Northwest (PNW) wheat, barley, legume and canola varieties are susceptible to the broad host-range soilborne pathogens that cause Rhizoctonia root rot and Pythium root rot. Effective control of these diseases will likely require additional approaches and resources. We have identified promisi...

  20. Influence of weed species and time of glyphosate application on Rhizoctonia root rot of barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG-8 causes root disease in wheat, barley, canola and other small grains in the dryland inland Pacific Northwest. The pathogen survives between crops on roots of volunteers and grassy weeds. Destroying this green bridge with herbicides such as glyphosate is a common tactic to cont...

  1. Infection cushion formation by Rhizoctonia spp. on peanut and wheat root systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The formation of infection cushions by Rhizoctonia solani (isolate G-24) and R. cerealis (isolate Fellers) was examined on cellophane membranes in response to stimulation by roots of peanut (Okrun, Tamspan 90, Southwest runner and Line 209) and hard red winter wheat (Jagger, 2137, and 2174). Root s...

  2. Incidence and spatial distribution of Rhizoctonia and Pythium species determined with real-time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Populations of Rhizoctonia and Pythium are diverse in eastern Washington, with multiple species/anastomosis groups present throughout the region and within individual fields. Recent evidence suggests that species composition may be influenced by crop rotation. The Cook Agronomy Farm near Pullman, WA...

  3. RL-SAGE ANALYSIS OF THE RICE DEFENSE TRANSCRIPTOME DURING RICE AND RHIZOCTONIA SOLANI INTERACTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, two RL-SAGE libraries were made from the R. solani infected and control plants of Jasmine 85, which is moderately resi...

  4. Postharvet losses associated with Rhizoctonia crown and root rot of sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the prevalence of Rhizoctonia crown and root rot (RCRR) increases, more diseased sugarbeet (Beta vulgaris L.) roots are destined for storage piles. To investigate the effect of RCRR on storage properties, roots with similar symptoms were grouped and extractable sucrose, invert sugar, and respirat...

  5. Weather-Based forecasting of Rhizoctonia web blight development on container-grown azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungicides are the only approach currently used to control Rhizoctonia web blight on container-grown azalea. The most reliable criterion for timing fungicides has been a fixed calendar date with adjustment for year-to-year differences in disease progression made by monitoring early-season increase o...

  6. Rhizoctonia Crown and Root Rot Resistance of Beta PI's from the USDA-ARS NPGS, 2009.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beta vulgaris plant introductions (PI) were screened for Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. Inoculum of R. solani isolate R-9 (AG-2-2), colonized to dry barley and course ground, was applied to the crown of plants at a rate of 4.8 g/m. Beets were lifted...

  7. Stunting of onion caused by Rhizoctonia spp. isolated from the Columbia Basin of Oregon and Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2009 and 2010, 45 isolates of Rhizoctonia spp. were recovered from onion bulb crops in the semi-arid Columbia Basin of Oregon and Washington, in which patches of severely stunted onion plants developed following rotation with winter cereal cover crops. Characterization of isolates recovered f...

  8. SUPPRESSION OF RHIZOCTONIA ROOT ROT BY STREPTOMYCES IN BRASSICA SEED MEAL-AMENDED

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amendment of soil with 0.5% Brassica napus (rape)seed (RSM) confers systemic protection against Rhizoctonia solani AG-5 root infection of apple seedlings. The development a R. solani-suppressive state in soil amended with low-glucosinolate B. napus var. Athena RSM was prevented by steam pasteurizat...

  9. Real-time detection and quantification of Rhizoctonia and Pythium species on the Cook Agronomy Farm.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Populations of Rhizoctonia and Pythium are diverse in eastern Washington, with multiple species/anastomosis groups present throughout the region and within individual fields. The process of identifying the pathogen present in a sample is laborious and the high diversity increases the difficulty in a...

  10. Influence of rhizoctonia-bacterial root rot complex on storability of sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rhizoctonia-bacterial root rot complex can lead to yield loss in the field but may also lead to problems with sucrose loss in storage. Thus, studies were conducted to investigate if placing sugarbeet roots suffering from root rot together with healthy roots could compromise the ability of the h...

  11. Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizotonia crown and root rot of sugarbeet (Beta vulgaris L), caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. T...

  12. Stem Rot on Adzuki Bean (Vigna angularis) Caused by Rhizoctonia solani AG 4 HGI in China

    PubMed Central

    Sun, Suli; Xia, Changjian; Zhang, Jiqing; Duan, Canxing; Wang, Xiaoming; Wu, Xiaofei; Lee, Suk-Ha; Zhu, Zhendong

    2015-01-01

    During late August and early September 2011, stem rot symptoms were observed on adzuki bean plants (Vigna angularis) growing in fields located in Beijing and Hebei Province, China, respectively. In this study, four isolates were obtained from infected stems of adzuki bean plants. Based on their morphology, and sequence and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the ribosomal DNA internal transcribed spacers (rDNA-ITS) region, the four isolates were identified as Rhizoctonia solani in anastomosis group (AG) 4 HGI. Pathogenicity tests showed that all isolates were strongly pathogenic to adzuki bean and resulted in serious wilt symptoms which was similar to observations in the fields. Additionally, the isolates infected several other crops and induced related rot on the roots and basal stems. To our knowledge, this is the first report of Rhizoctonia solani AG 4 HGI causing stem rot on adzuki bean. PMID:25774112

  13. A fungal growth model fitted to carbon-limited dynamics of Rhizoctonia solani.

    PubMed

    Jeger, M J; Lamour, A; Gilligan, C A; Otten, W

    2008-01-01

    Here, a quasi-steady-state approximation was used to simplify a mathematical model for fungal growth in carbon-limiting systems, and this was fitted to growth dynamics of the soil-borne plant pathogen and saprotroph Rhizoctonia solani. The model identified a criterion for invasion into carbon-limited environments with two characteristics driving fungal growth, namely the carbon decomposition rate and a measure of carbon use efficiency. The dynamics of fungal spread through a population of sites with either low (0.0074 mg) or high (0.016 mg) carbon content were well described by the simplified model with faster colonization for the carbon-rich environment. Rhizoctonia solani responded to a lower carbon availability by increasing the carbon use efficiency and the carbon decomposition rate following colonization. The results are discussed in relation to fungal invasion thresholds in terms of carbon nutrition. PMID:18312538

  14. Rhizoctonia Crown and Root Rot Resistance of Beta Plant Introductions from the USDA, Agricultural Research Service's National Plant Germplasm System, 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty wild beet (Beta vulgaris subsp. maritima (L.) Arcang) plant introduction (PI) accessions from the Beta collection of the USDA-ARS National Plant Germplasm System were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. The Rhizoctonia sc...

  15. Cropping Systems and Cultural Practices Determine the Rhizoctonia Anastomosis Groups Associated with Brassica spp. in Vietnam

    PubMed Central

    Soltaninejad, Saman; Höfte, Monica

    2014-01-01

    Ninety seven Rhizoctonia isolates were collected from different Brassica species with typical Rhizoctonia symptoms in different provinces of Vietnam. The isolates were identified using staining of nuclei and sequencing of the rDNA-ITS barcoding gene. The majority of the isolates were multinucleate R. solani and four isolates were binucleate Rhizoctonia belonging to anastomosis groups (AGs) AG-A and a new subgroup of A-F that we introduce here as AG-Fc on the basis of differences in rDNA-ITS sequence. The most prevalent multinucleate AG was AG 1-IA (45.4% of isolates), followed by AG 1-ID (17.5%), AG 1-IB (13.4%), AG 4-HGI (12.4%), AG 2-2 (5.2%), AG 7 (1.0%) and an unknown AG related to AG 1-IA and AG 1-IE that we introduce here as AG 1-IG (1.0%) on the basis of differences in rDNA-ITS sequence. AG 1-IA and AG 1-ID have not been reported before on Brassica spp. Pathogenicity tests revealed that isolates from all AGs, except AG-A, induced symptoms on detached leaves of several cabbage species. In in vitro tests on white cabbage and Chinese cabbage, both hosts were severely infected by AG 1-IB, AG 2-2, AG 4-HGI, AG 1-IG and AG-Fc isolates, while under greenhouse conditions, only AG 4-HGI, AG 2-2 and AG-Fc isolates could cause severe disease symptoms. The occurrence of the different AGs seems to be correlated with the cropping systems and cultural practices in different sampling areas suggesting that agricultural practices determine the AGs associated with Brassica plants in Vietnam. PMID:25372406

  16. PROTEOMIC AND GENETIC APPROACHES TO IDENTIFYING DEFENSE-RELATED PROTEINS IN RICE CHALLENGED WITH THE FUNGAL PATHOGEN RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight, caused by the fungus Rhizoctonia solani, is a major disease of rice worldwide, but little is known about the host response to infection. The objective of this study was to identify proteins and DNA markers in resistant and susceptible rice associated with response to infection by R. s...

  17. Carbon source-dependent efficacy of anaerobic soil disinfestation (ASD) in suppression of Rhizoctonia root rot of apple

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG-5 is a significant component of the pathogen complex that incites apple replant disease (ARD). A non-fumigant alternative, such as ASD, is highly desired for control of ARD. We examined the influence of carbon input as a determinant of ASD efficacy in the supression of apple ...

  18. Biological control of Rhizoctonia root rot on bean by phenazine- and cyclic lipopeptide-producing Pseudomonas CMR12a

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas CMR12a was previously selected as an efficient biocontrol strain producing phenazines and cyclic lipopeptides (CLPs). In this study, biocontrol capacity of Pseudomonas CMR12a against Rhizoctonia root rot of bean and the involvement of phenazines and CLPs in this ability were tested. Two ...

  19. Characterization of fungi (Fusarium and Rhizoctonia) and oomycetes (Phytophthora and Pythium) associated with apple orchards in South Africa.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several species of fungi and oomycetes including Fusarium, Rhizoctonia, Phytophthora and Pythium have been reported as root pathogens of apple where they contribute to a phenomenon known as apple replant disease. In South Africa, very little is known about the specific species in these genera and th...

  20. Pathogenicity, characterization and comparative virulence of Rhizoctonia spp. from insect-galled roots of Lepidium draba in Europe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The association of Rhizoctonia spp. with insect-damaged and diseased tissue of the invasive perennial Lepidium draba was documented throughout the range of L. draba that was surveyed in Europe, including Hungary, Austria, Switzerland and France. Samples that could be both maintained under cooled con...

  1. Screening Rhizoctonia crown and root rot resistance of Beta PIs from the USDA-ARS, National Plant Germplasm System, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty beet (Beta vulgaris subsp. maritima (L.) Arcang and Beta vulgaris subsp. vulgaris L.) plant introduction (PI) accessions from the Beta collection of the USDA-ARS National Plant Germplasm System were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Re...

  2. Gene expression profiling of the plant pathogenic basidiomycetous fungus Rhizoctonia solani AG 4 reveals putative virulence factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is a ubiquitous basidiomycetous soilborne fungal pathogen causing damping off of seedlings, aerial blights and postharvest diseases. To gain insight into the molecular mechanisms of pathogenesis a global approach based on analysis of expressed sequence tags (ESTs) was undertaken. ...

  3. Identity and Specificity of Rhizoctonia-Like Fungi from Different Populations of Liparis japonica (Orchidaceae) in Northeast China

    PubMed Central

    Ding, Rui; Chen, Xu-Hui; Zhang, Li-Jun; Yu, Xiao-Dan; Qu, Bo; Duan, Ru; Xu, Yu-Feng

    2014-01-01

    Mycorrhizal association is known to be important to orchid species, and a complete understanding of the fungi that form mycorrhizas is required for orchid ecology and conservation. Liparis japonica (Orchidaceae) is a widespread terrestrial photosynthetic orchid in Northeast China. Previously, we found the genetic diversity of this species has been reduced recent years due to habitat destruction and fragmentation, but little was known about the relationship between this orchid species and the mycorrhizal fungi. The Rhizoctonia-like fungi are the commonly accepted mycorrhizal fungi associated with orchids. In this study, the distribution, diversity and specificity of culturable Rhizoctonia-like fungi associated with L. japonica species were investigated from seven populations in Northeast China. Among the 201 endophytic fungal isolates obtained, 86 Rhizoctonia-like fungi were identified based on morphological characters and molecular methods, and the ITS sequences and phylogenetic analysis revealed that all these Rhizoctonia-like fungi fell in the same main clade and were closely related to those of Tulasnella calospora species group. These findings indicated the high mycorrhizal specificity existed in L. japonica species regardless of habitats at least in Northeast China. Our results also supported the wide distribution of this fungal partner, and implied that the decline of L. japonica in Northeast China did not result from high mycorrhizal specificity. Using culture-dependent technology, these mycorrhizal fungal isolates might be important sources for the further utilizing in orchids conservation. PMID:25140872

  4. Sequence variation of the rDNA internal transcribed spacer (ITS) region among isolates of Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is a common and highly heterogeneous fungal species. Sub-specific groups have been created based on hyphal anastomosis (AGs). One of the newer AGs described is AG-11 from soybean and rice seedlings or soil in Arkansas and lupine in Australia (Carling et al. Phytopathology 84:1378-...

  5. Screening different Brassica spp. germplasm for resistance to Rhizoctonia solani AG-2-1 and AG-8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poor stands of canola seedlings in Pacific Northwest (PNW) have been associated with Rhizoctonia solani AG-2-1 and AG-8. A total of eighty five genotypes of Brassica napus, B. rapa, B. carinata, B. juncea and Sinapsis alba were evaluated in the growth chamber for their resistance to both R. solani A...

  6. Rapid Determination of Rice Cultivar Responses to the Sheath Blight Pathogen Rhizoctonia solani Using a Micro-Chamber Screening Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An accurate greenhouse screening method has not previously been developed to identify host response to sheath blight disease caused by Rhizoctonia solani Kühn that causes significant economic losses in rice yield worldwide. The unavailability of a robust pathometric screening system in the greenhou...

  7. Identification of signatory secondary metabolites during mycoparasitism of Rhizoctonia solani by Stachybotrys elegans

    PubMed Central

    Chamoun, Rony; Aliferis, Konstantinos A.; Jabaji, Suha

    2015-01-01

    Stachybotrys elegans is able to parasitize the fungal plant pathogen Rhizoctonia solani AG-3 following a complex and intimate interaction, which, among others, includes the production of cell wall-degrading enzymes, intracellular colonization, and expression of pathogenic process encoding genes. However, information on the metabolome level is non-existent during mycoparasitism. Here, we performed a direct-infusion mass spectrometry (DIMS) metabolomics analysis using an LTQ Orbitrap analyzer in order to detect changes in the profiles of induced secondary metabolites of both partners during this mycoparasitic interaction 4 and 5 days following its establishment. The diketopiperazine(s) (DKPs) cyclo(S-Pro-S-Leu)/cyclo(S-Pro-S-Ile), ethyl 2-phenylacetate, and 3-nitro-4-hydroxybenzoic acid were detected as the primary response of Rhizoctonia 4 days following dual-culturing with Stachybotrys, whereas only the latter metabolite was up-regulated 1 day later. On the other hand, trichothecenes and atranones were mycoparasite-derived metabolites identified during mycoparasitism 4 and 5 days following dual-culturing. All the above secondary metabolites are known to exhibit bioactivity, including fungitoxicity, and represent key elements that determine the outcome of the interaction being studied. Results could be further exploited in programs for the evaluation of the bioactivity of these metabolites per se or their chemical analogs, and/or genetic engineering programs to obtain more efficient mycoparasite strains with improved efficacy and toxicological profiles. PMID:25972848

  8. Role of Bacterial Communities in the Natural Suppression of Rhizoctonia solani Bare Patch Disease of Wheat (Triticum aestivum L.)

    PubMed Central

    Yin, Chuntao; Hulbert, Scot H.; Schroeder, Kurtis L.; Mavrodi, Olga; Mavrodi, Dmitri; Dhingra, Amit; Schillinger, William F.

    2013-01-01

    Rhizoctonia bare patch and root rot disease of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants and limits the yield of direct-seeded (no-till) wheat in the Pacific Northwest of the United States. At the site of a long-term cropping systems study near Ritzville, WA, a decline in Rhizoctonia patch disease was observed over an 11-year period. Bacterial communities from bulk and rhizosphere soil of plants from inside the patches, outside the patches, and recovered patches were analyzed by using pyrosequencing with primers designed for 16S rRNA. Taxa in the class Acidobacteria and the genus Gemmatimonas were found at higher frequencies in the rhizosphere of healthy plants outside the patches than in that of diseased plants from inside the patches. Dyella and Acidobacteria subgroup Gp7 were found at higher frequencies in recovered patches. Chitinophaga, Pedobacter, Oxalobacteriaceae (Duganella and Massilia), and Chyseobacterium were found at higher frequencies in the rhizosphere of diseased plants from inside the patches. For selected taxa, trends were validated by quantitative PCR (qPCR), and observed shifts of frequencies in the rhizosphere over time were duplicated in cycling experiments in the greenhouse that involved successive plantings of wheat in Rhizoctonia-inoculated soil. Chryseobacterium soldanellicola was isolated from the rhizosphere inside the patches and exhibited significant antagonism against R. solani AG-8 in vitro and in greenhouse tests. In conclusion, we identified novel bacterial taxa that respond to conditions affecting bare patch disease symptoms and that may be involved in suppression of Rhizoctonia root rot and bare batch disease. PMID:24056471

  9. Production of Chitinases and ?-1,3-Glucanases by Stachybotrys elegans, a Mycoparasite of Rhizoctonia solani

    PubMed Central

    Tweddell, Russell J.; Jabaji-Hare, Suha H.; Charest, Pierre M.

    1994-01-01

    The in vitro production of chitinases and ?-1,3-glucanases by Stachybotrys elegans, a mycoparasite of Rhizoctonia solani, was examined under various culture conditions, such as carbon and nitrogen sources, pH, and incubation period. Production of both enzymes was influenced by the carbon source incorporated into the medium and was stimulated by acidic pH and NaNO3. The activity of both enzymes was very low in culture filtrates from cells grown on glucose and sucrose compared with that detected on chitin (for chitinases) and cell wall fragments (for ?-1,3-glucanases). Protein electrophoresis revealed that, depending on the carbon source used, different isoforms of chitinases and ?-1,3-glucanases were detected. S. elegans culture filtrates, possessing ?-1,3-glucanase and chitinase activities, were capable of degrading R. solani mycelium. Images PMID:16349178

  10. Efficacy of Bacillus subtilis V26 as a biological control agent against Rhizoctonia solani on potato.

    PubMed

    Ben Khedher, Saoussen; Kilani-Feki, Olfa; Dammak, Mouna; Jabnoun-Khiareddine, Hayfa; Daami-Remadi, Mejda; Tounsi, Slim

    2015-12-01

    The aim of this study is to evaluate the efficacy of the strain Bacillus subtilis V26, a local isolate from the Tunisian soil, to control potato black scurf caused by Rhizoctonia solani. The in vitro antifungal activity of V26 significantly inhibited R. solani growth compared to the untreated control. Microscopic observations revealed that V26 caused considerable morphological deformations of the fungal hyphae such as vacuolation, protoplast leakage and mycelia crack. The most effective control was achieved when strain V26 was applied 24h prior to inoculation (protective activity) in potato slices. The antagonistic bacterium V26 induced significant suppression of root canker and black scurf tuber colonization compared to untreated controls with a decrease in incidence disease of 63% and 81%, respectively, and promoted plant growth under greenhouse conditions on potato plants. Therefore, B. subtilis V26 has a great potential to be commercialized as a biocontrol agent against R. solani on potato crops. PMID:26563555

  11. Molecular characterization of a novel mycovirus from Rhizoctonia fumigata AG-Ba isolate C-314 Baishi.

    PubMed

    Li, Yanqiong; Xu, Ping; Zhang, Lifang; Xia, Zhenyuan; Qin, Xiyun; Yang, Genhua; Mo, Xiaohan

    2015-09-01

    The complete genome sequence of a novel dsRNA virus isolated from Rhizoctonia fumigata AG-Ba isolate C-314 Baishi (designated as Rhizoctonia fumigata virus 1, RfV1) was determined. The RfV1 genome was 9,907 bp in length and contained two open reading frames (ORFs). ORF1 potentially coded for a 198.10-kDa protein (P1). P1 shared low but significant amino acid sequence similarity to the putative protein encoded by Lentinula edodes mycovirus (LeV) ORF1. P1 contained a NUDIX domain, which was also present in the putative proteins encoded by the ORF1s of LeV and Phlebiopsis gigantea large virus 1 (PgLV-1). ORF2 potentially coded for a 146.72-kDa protein (P2) that contained the conserved motifs of the RNA-dependent RNA polymerase (RdRp). ORF1 and ORF2 were overlapping, and it was predicted that ORF2 could be translated as a fusion with ORF1 via a ribosomal -1 frameshifting mechanism. Phylogenetic analysis indicated that RfV1 clustered with PgLV-1, LeV and Rosellinia necatrix megabirnavirus 1 (RnMBV1) in a separate clade independent of other virus genera. We propose that RfV1, along with PgLV-1 and LeV, should be grouped into a new viral genus related to the family Megabirnaviridae. This is the first report of the full-length genome sequence of a novel mycovirus isolated from R. fumigata. PMID:26133296

  12. Draft Genome Sequence of Pseudomonas simiae Strain 2-36, an In Vitro Antagonist of Rhizoctonia solani and Gaeumannomyces graminis

    PubMed Central

    Adam, Zaky; Chen, Qing; Xu, Renlin; Diange, Adolf E.; Bromfield, Eden S. P.

    2015-01-01

    Pseudomonas simiae 2-36, isolated from a field plot under long-term mineral fertilization, exhibited strong in vitro antagonistic activities against Rhizoctonia solani and Gaeumannomyces graminis. We report here the draft genome sequence of Pseudomonas simiae 2-36, consisting of 6.4 Mbp with a 60.25% G+C content and 5,790 predicted protein-coding sequences. PMID:25657286

  13. Temperature, moisture, and fungicide effects in managing Rhizoctonia root and crown rot of sugar beet.

    PubMed

    Bolton, Melvin D; Panella, Lee; Campbell, Larry; Khan, Mohamed F R

    2010-07-01

    Rhizoctonia solani AG-2-2 is the causal agent of Rhizoctonia root and crown rot in sugar beet; however, recent increases in disease incidence and severity were grounds to reevaluate this pathosystem. To assess the capacity at which other anastomosis groups (AGs) are able to infect sugar beet, 15 AGs and intraspecific groups (ISGs) were tested for pathogenicity on resistant ('FC708 CMS') and susceptible ('Monohikari') seedlings and 10-week-old plants. Several AGs and ISGs were pathogenic on seedlings regardless of host resistance but only AG-2-2 IIIB and AG-2-2 IV caused significant disease on 10-week-old plants. Because fungicides need to be applied prior to infection for effective disease control, temperature and moisture parameters were assessed to identify potential thresholds that limit infection. Root and leaf disease indices were used to evaluate disease progression of AG-2-2 IIIB- and AG-2-2 IV-inoculated plants in controlled climate conditions of 7 to 22 growing degree days (GDDs) per day. Root disease ratings were positively correlated with increasing temperature of both ISGs, with maximum disease symptoms occurring at 22 GDDs/day. No disease symptoms were evident from either ISG at 10 GDDs/day but disease symptoms did occur in plants grown in growth chambers set to 11 GDDs/day. Using growth chambers adjusted to 22 GDDs/day, disease was evaluated at 25, 50, 75, and 100% moisture-holding capacity (MHC). Disease symptoms for each ISG were highest in soils with 75 and 100% MHC but disease still occurred at 25% MHC. Isolates were tested for their ability to cause disease at 1, 4, and 8 cm from the plant hypocotyl. Only AG-2-2 IIIB was able to cause disease symptoms at 8 cm during the evaluation period. In all experiments, isolates of AG-2-2 IIIB were found to be more aggressive than AG-2-2 IV. Using environmental parameters that we identified as the most conducive to disease development, azoxystrobin, prothioconazole, pyraclostrobin, difenoconazole/propiconazole, flutolanil, polyoxin D, and a water control were evaluated for their ability to suppress disease development by AG-2-2 IIIB and AG-2-2 IV 17 days after planting. Flutolanil, polyoxin-D, and azoxystrobin provided the highest level of disease suppression. Because R. solani AG-2-2 IIIB and AG-2-2 IV are affected by temperature and moisture, growers may be able to evaluate environmental parameters for optimization of fungicide application. PMID:20528187

  14. Trichoderma harzianum genes induced during growth on Rhizoctonia solani cell walls.

    PubMed

    Vasseur, V; Van Montagu, M; Goldman, G H

    1995-04-01

    Trichoderma harzianum is a biocontrol agent that attacks a range of economically important phytopathogenic fungi. In an attempt to identify genes specifically expressed by T. harzianum during growth on cell walls of Rhizoctonia solani, we carried out differential screening of an induced cDNA library. In this paper we report the analysis of the sequence and expression of two cDNA clones that encode putative mycoparasitism-related proteins of T. harzianum. One of these clones corresponds to a gene, inda1, that encodes a protein of 570 amino acids with a predicted molecular mass of 62,853 Da. The predicted amino acid sequence of inda1 showed a high degree of similarity with amino acid permeases from several other organisms. The other cDNA clone corresponds to a gene, indc11, that encodes a novel protein of 340 amino acids with a predicted molecular mass of 37,010 Da. The use of this methodology should provide specific genetic markers to follow mycoparasitism by Trichoderma spp. PMID:7773384

  15. Biocontrol potential of soybean bacterial endophytes against charcoal rot fungus, Rhizoctonia bataticola.

    PubMed

    Senthilkumar, M; Swarnalakshmi, K; Govindasamy, V; Lee, Young Keun; Annapurna, K

    2009-04-01

    A total of 137 bacterial isolates from surface sterilized root, stem, and nodule tissues of soybean were screened for their antifungal activity against major phytopathogens like Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium udam, and Sclerotium rolfsii. Nine bacterial endophytes suppressed the pathogens under in vitro plate assay. These were characterized biochemically and identified at the genus level based on their partial sequence analysis of 16S rDNA. Eight of the isolates belonged to Bacillus and one to Paenibacillus. The phylogenetic relationship among the selected isolates was studied and phylogenetic trees were generated. The selected isolates were screened for biocontrol traits like production of hydrogen cyanide (HCN), siderophore, hydrolytic enzymes, antibiotics, and plant growth promoting traits like indole 3-acetic acid production, phosphate solubilization, and nitrogen fixation. A modified assessment scheme was used to select the most efficient biocontrol isolates Paenibacillus sp. HKA-15 (HKA-15) and Bacillus sp. HKA-121 (HKA-121) as potential candidates for charcoal rot biocontrol as well as soybean plant growth promotion. PMID:19067044

  16. Molecular Characterization and Screening for Sheath Blight Resistance Using Malaysian Isolates of Rhizoctonia solani

    PubMed Central

    Rosli, Marhamah Md.; Shin Tze, Ong

    2014-01-01

    Two field isolates of Rhizoctonia solani were isolated from infected paddy plants in Malaysia. These isolates were verified via ITS-rDNA analysis that yielded ~720?bp products of the ITS1-5.8S-ITS4 region, respectively. The sequenced products showed insertion and substitution incidences which may result in strain diversity and possible variation in disease severity. These strains showed some regional and host-specific relatedness via Maximum Likelihood and further phylogenetic analysis via Maximum Parsimony showed that these strains were closely related to R. solani AG1-1A (with 99-100% identity). Subsequent to strain verification and analysis, these isolates were used in the screening of twenty rice varieties for tolerance or resistance to sheath blight via mycelial plug method where both isolates (1801 and 1802) showed resistance or moderate resistance to Teqing, TETEP, and Jasmine 85. Isolate 1802 was more virulent based on the disease severity index values. This study also showed that the mycelial plug techniques were efficient in providing uniform inoculum and humidity for screening. In addition this study shows that the disease severity index is a better mode of scoring for resistance compared to lesion length. These findings will provide a solid basis for our future breeding and screening activities at the institution. PMID:25258710

  17. Transcriptional responses of the bacterial antagonist Serratia plymuthica to the fungal phytopathogen Rhizoctonia solani.

    PubMed

    Neupane, Saraswoti; Finlay, Roger D; Alström, Sadhna; Elfstrand, Malin; Högberg, Nils

    2015-02-01

    Rhizobacteria with biocontrol ability exploit a range of mechanisms to compete successfully with other microorganisms and to ensure their growth and survival in the rhizosphere, ultimately promoting plant growth. The rhizobacterium Serratia plymuthica?AS13 is able to promote oilseed rape growth and improve seedling survival in the presence of the fungal pathogen, Rhizoctonia solani?AG 2-1; however, our understanding of the mechanisms underlying the antagonism of Serratia is limited. To elucidate possible mechanisms, genome-wide gene expression profiling of S.?plymuthica?AS13 was carried out in the presence or absence of R.?solani. We used RNA sequencing methodology to obtain a comprehensive overview of Serratia gene expression in response to R.?solani. The differential gene expression profiles of S.?plymuthica?AS13 revealed significantly increased expression of genes related to the biosynthesis of the antibiotic pyrrolnitrin (prnABCD), protease production and transporters. The results presented here provide evidence that antibiosis is a major functional mechanism underlying the antagonistic behaviour of S.?plymuthica?AS13. PMID:25139310

  18. Chitinase production by Bacillus subtilis ATCC 11774 and its effect on biocontrol of Rhizoctonia diseases of potato.

    PubMed

    Saber, Wesam I A; Ghoneem, Khalid M; Al-Askar, Abdulaziz A; Rashad, Younes M; Ali, Abeer A; Rashad, Ehsan M

    2015-12-01

    Stem canker and black scurf of potato, caused by Rhizoctonia solani, can be serious diseases causing an economically significant damage. Biocontrol activity of Bacillus subtilis ATCC 11774 against the Rhizoctonia diseases of potato was investigated in this study. Chitinase enzyme was optimally produced by B. subtilis under batch fermentation conditions similar to those of the potato-growing soil. The maximum chitinase was obtained at initial pH 8 and 30 °C. In vitro, the lytic action of the B. subtilis chitinase was detected releasing 355 ?g GlcNAc ml(-1) from the cell wall extract of R. solani and suggesting the presence of various chitinase enzymes in the bacterial filtrate. In dual culture test, the antagonistic behavior of B. subtilis resulted in the inhibition of the radial growth of R. solani by 48.1% after 4 days. Moreover, the extracted B. subtilis chitinase reduced the growth of R. solani by 42.3% when incorporated with the PDA plates. Under greenhouse conditions, application of a bacterial suspension of B. subtilis at 109 cell mL(-1) significantly reduced the disease incidence of stem canker and black scurf to 22.3 and 30%, respectively. In addition, it significantly improved some biochemical parameters, growth and tubers yield. Our findings indicate two points; firstly, B. subtilis possesses a good biocontrol activity against Rhizoctonia diseases of potato, secondly, the harmonization and suitability of the soil conditions to the growth and activity of B. subtilis guaranteed a high controlling capacity against the target pathogen. PMID:26616375

  19. The impact of the pathogen Rhizoctonia solani and its beneficial counterpart Bacillus amyloliquefaciens on the indigenous lettuce microbiome

    PubMed Central

    Erlacher, Armin; Cardinale, Massimiliano; Grosch, Rita; Grube, Martin; Berg, Gabriele

    2014-01-01

    Lettuce belongs to the most commonly raw eaten food worldwide and its microbiome plays an important role for both human and plant health. Yet, little is known about the impact of potentially occurring pathogens and beneficial inoculants of the indigenous microorganisms associated with lettuce. To address this question we studied the impact of the phytopathogenic fungus Rhizoctonia solani and the biological control agent Bacillus amyloliquefaciens FZB42 on the indigenous rhizosphere and phyllosphere community of greenhouse-grown lettuce at two plant stages. The rhizosphere and phyllosphere gammaproteobacterial microbiomes of lettuce plants showed clear differences in their overall and core microbiome composition as well as in corresponding diversity indices. The rhizosphere was dominated by Xanthomonadaceae (48%) and Pseudomonadaceae (37%) with Rhodanobacter, Pseudoxanthomonas, Dokdonella, Luteimonas, Steroidobacter, Thermomonas as core inhabitants, while the dominating taxa associated to phyllosphere were Pseudomonadaceae (54%), Moraxellaceae (16%) and Enterobacteriaceae (25%) with Alkanindiges, Pantoea and a group of Enterobacteriaceae unclassified at genus level. The preferential occurrence of enterics in the phyllosphere was the most significant difference between both habitats. Additional enhancement of enterics on the phyllosphere was observed in bottom rot diseased lettuce plants, while Acinetobacter and Alkanindiges were identified as indicators of healthy plants. Interestingly, the microbial diversity was enhanced by treatment with both the pathogen, and the co-inoculated biological control agent. The highest impact and bacterial diversity was found by Rhizoctonia inoculation, but FZB42 lowered the impact of Rhizoctonia on the microbiome. This study shows that the indigenous microbiome shifts as a consequence to pathogen attack but FZB42 can compensate these effects, which supports their role as biocontrol agent and suggests a novel mode of action. PMID:24795707

  20. Antibiosis functions during interactions of Trichoderma afroharzianum and Trichoderma gamsii with plant pathogenic Rhizoctonia and Pythium.

    PubMed

    Zhang, Xinjian; Harvey, Paul R; Stummer, Belinda E; Warren, Rosemary A; Zhang, Guangzhi; Guo, Kai; Li, Jishun; Yang, Hetong

    2015-09-01

    Trichoderma afroharzianum is one of the best characterized Trichoderma species, and strains have been utilized as plant disease suppressive inoculants. In contrast, Trichoderma gamsii has only recently been described, and there is limited knowledge of its disease suppressive efficacies. Comparative studies of changes in gene expression during interactions of these species with their target plant pathogens will provide fundamental information on pathogen antibiosis functions. In the present study, we used complementary DNA amplified fragment length polymorphism (cDNA-AFLP) analysis to investigate changes in transcript profiling of T. afroharzianum strain LTR-2 and T. gamsii strain Tk7a during in vitro interactions with plant pathogenic Rhizoctonia solani and Pythium irregulare. Considerable differences were resolved in the overall expression profiles of strains LTR-2 and Tk7a when challenged with either plant pathogen. In strain LTR-2, previously reported mycoparasitism-related genes such as chitinase, polyketide synthase, and non-ribosomal peptide synthetase were found to be differentially expressed. This was not so for strain Tk7a, with the only previously reported antibiosis-associated genes being small secreted cysteine-rich proteins. Although only one differentially expressed gene was common to both strains LTR-2 and Tk7a, numerous genes reportedly associated with pathogen antibiosis processes were differentially expressed in both strains, including degradative enzymes and membrane transport proteins. A number of novel potential antibiosis-related transcripts were found from strains LTR-2 and Tk7a and remain to be identified. The expression kinetics of 20 Trichoderma (10 from strain LTR-2, 10 from strain Tk7a) transcript-derived fragments (TDFs) were quantified by quantitative reverse transcription PCR (RT-qPCR) at pre- and post-mycelia contact stages of Trichoderma-prey interactions, thereby confirming differential gene expression. Collectively, this research is providing information to elucidate the antibiosis mechanisms and disease suppressive activities of T. afroharzianum and T. gamsii against soilborne fungal and oomycete plant pathogens. PMID:26231513

  1. Biocontrol of Rhizoctonia solani, the causal agent of bean damping-off by fluorescent pseudomonads.

    PubMed

    Afsharmanesh, H; Ahmadzadeh, M; Sharifi-Tehrani, A

    2006-01-01

    Rhizosphere bacteria belonging to the fluorescent pseudomonads are receiving increasing attention for the protection of plants against soil-borne fungal pathogens. Among these pathogens, Rhizoctonia solani, the causal agent of bean damping- off is very important in bean fields of Iran. In this study, the antagonistic activity of 46 isolates of fluorescent pseudomonads (isolated from different area of Iran) and Pseudomonas fluorescens strain CHA0 investigated against one isolate of R. solani. About 64% of isolates revealed antagonistic activity against R. solani. Production of antifungal metabolites such as HCN, siderophore and protease was evaluated. The results showed that 97.8%, 17% and 78% of isolates produced siderophore, HCN and protease respectively. There was no significant correlation between antagonistic activity and production of these metabolites. Isolates P-5, P-10 and P-32 with strain CHA0 were selected in order to investigate involvement of siderophore, volatile metabolites (HCN), and non-volatile metabolites in reducing mycelial growth of R. olani. Isolate P-5 showed much more inhibitory effect by production of volatile metabolites and siderophore. Non-volatile metabolites in isolates P-32 and P-5 completely inhibited mycelial growth of the fungus. After the primary labrotory tests, isolates P-14, P-35, P-30, P-5 and strain CHA0 were selected for in vivo experiments. These selected isolates with benomyl fungicide were used as seed coating and soil drenching in sterile soil under greenhouse condition. The result indicated that in seed treatment method, isolates P-30 by 66% had the most effect in disease reduction while in soil treatment method, strain CHAO by 60% had the most effect, such that this two isolates showed significant differences in comparison with plants inoculated with R. solani inoculums. PMID:17390854

  2. Identification, molecular characterization, and evolution of group I introns at the expansion segment D11 of 28S rDNA in Rhizoctonia species.

    PubMed

    González, Dolores

    2013-09-01

    The nuclear ribosomal DNA of Rhizoctonia species is polymorphic in terms of the nucleotide composition and length. Insertions of 349-410 nucleotides in length with characteristics of group I introns were detected at a single insertion point at the expansion segment D11 of 28S rDNA in 12 out of 64 isolates. Eleven corresponded to Rhizoctonia solani (teleomorph: Thanatephorous) and one (AG-Q) to Rhizoctonia spp. (teleomorph: Ceratobasidium). Sequence data showed that all but AG-Q contained conserved DNA catalytic core regions (P, Q, R, and S) essential for selfsplicing. The predicted secondary structure revealed that base-paired helices corresponded to subgroup IC1. Isolates from same anastomosis group and even subgroups within R. solani were variable with regard to possession of introns. Phylogenetic analyses indicated that introns were vertically transmitted. Unfortunately, sequence data from the conserved region from all 64 isolates were not useful for delimiting species. Analyses with IC1 introns at same insertion point, of both Ascomycota and Basidiomycota indicated the possibility of horizontal transfer at this site. The present study uncovered new questions on evolutionary pattern of change of these introns within Rhizoctonia species. PMID:24012302

  3. Effect of cropping system on composition of the Rhizoctonia populations recovered from canola and lupin in a winter rainfall region of South Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia spp. are important pathogens of a broad range of crop plants that are economically important to the farm economy of the Western Cape region of South Africa. However, there is little information concerning the identity and relative importance of these fungal pathogens, and the effect of ...

  4. CULTIVAR SPECIFIC RESPONSE TO THE HOST-SELECTIVE TOXIN PRODUCED BY RHIZOCTONIA SOLANI, THE CAUSAL PATHOGEN OF SHEATH BLIGHT DISEASE Of RICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath Blight, caused by Rhizoctonia solani, is widely regarded as one of the most important diseases of cultivated rice and germplasm improvement is essential for disease management. Genetic sources of tolerance for this disease are known, however, complex quantitative inheritance and high environ...

  5. Efficacy of fungicides to manage onion stunting caused by Rhizoctonia spp. in the Columbia Basin of Oregon and Washington, 2011-2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onion stunting, caused by Rhizoctonia spp., has become a significant soilborne problem of onion bulb crops planted in sandy soils in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Research on the epidemiology and management of this disease is in progress. ...

  6. High-resolution mapping of Rsn1, a locus controlling sensitivity of rice to a necrosis-inducing phytotoxin from Rhizoctonia solani AG1-IA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on all major crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa), one of the most important rice diseases worldwide. R. solani AG-IA produces a necrosis-inducing phytotoxin a...

  7. Rhizoctonia spp. dynamics and optimal timing of glyphosate application to cereal cover crops to manage onion stunting in Washington and Oregon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onion stunting or bare patch caused by Rhizoctonia spp. is an economically important disease in sandy soils of the Columbia Basin of Oregon and Washington. Patches of stunted onions develop where cover crops of wheat or barley are killed with a herbicide spray prior to spring planting of onion seed....

  8. A version of this article appeared in GreenMaster 41(3):28-30 (June 2006) A New Rhizoctonia Fungus on Turfgrass in Ontario

    E-print Network

    Hsiang, Tom

    several different names, including hot weather brown patch, leaf and sheath spot, leaf and sheath rot book on turfgrass diseases by Professors Smiley, Clarke and Dernoeden (2005), these Rhizoctonia species patch, but under hot weather conditions when yellow patch does not regularly occur. Sheath spot does

  9. Genome Sequencing and Comparative Genomics of the Broad Host-Range Pathogen Rhizoctonia solani AG8

    PubMed Central

    Hane, James K.; Anderson, Jonathan P.; Williams, Angela H.; Sperschneider, Jana; Singh, Karam B.

    2014-01-01

    Rhizoctonia solani is a soil-borne basidiomycete fungus with a necrotrophic lifestyle which is classified into fourteen reproductively incompatible anastomosis groups (AGs). One of these, AG8, is a devastating pathogen causing bare patch of cereals, brassicas and legumes. R. solani is a multinucleate heterokaryon containing significant heterozygosity within a single cell. This complexity posed significant challenges for the assembly of its genome. We present a high quality genome assembly of R. solani AG8 and a manually curated set of 13,964 genes supported by RNA-seq. The AG8 genome assembly used novel methods to produce a haploid representation of its heterokaryotic state. The whole-genomes of AG8, the rice pathogen AG1-IA and the potato pathogen AG3 were observed to be syntenic and co-linear. Genes and functions putatively relevant to pathogenicity were highlighted by comparing AG8 to known pathogenicity genes, orthology databases spanning 197 phytopathogenic taxa and AG1-IA. We also observed SNP-level “hypermutation” of CpG dinucleotides to TpG between AG8 nuclei, with similarities to repeat-induced point mutation (RIP). Interestingly, gene-coding regions were widely affected along with repetitive DNA, which has not been previously observed for RIP in mononuclear fungi of the Pezizomycotina. The rate of heterozygous SNP mutations within this single isolate of AG8 was observed to be higher than SNP mutation rates observed across populations of most fungal species compared. Comparative analyses were combined to predict biological processes relevant to AG8 and 308 proteins with effector-like characteristics, forming a valuable resource for further study of this pathosystem. Predicted effector-like proteins had elevated levels of non-synonymous point mutations relative to synonymous mutations (dN/dS), suggesting that they may be under diversifying selection pressures. In addition, the distant relationship to sequenced necrotrophs of the Ascomycota suggests the R. solani genome sequence may prove to be a useful resource in future comparative analysis of plant pathogens. PMID:24810276

  10. Genome sequencing and comparative genomics of the broad host-range pathogen Rhizoctonia solani AG8.

    PubMed

    Hane, James K; Anderson, Jonathan P; Williams, Angela H; Sperschneider, Jana; Singh, Karam B

    2014-05-01

    Rhizoctonia solani is a soil-borne basidiomycete fungus with a necrotrophic lifestyle which is classified into fourteen reproductively incompatible anastomosis groups (AGs). One of these, AG8, is a devastating pathogen causing bare patch of cereals, brassicas and legumes. R. solani is a multinucleate heterokaryon containing significant heterozygosity within a single cell. This complexity posed significant challenges for the assembly of its genome. We present a high quality genome assembly of R. solani AG8 and a manually curated set of 13,964 genes supported by RNA-seq. The AG8 genome assembly used novel methods to produce a haploid representation of its heterokaryotic state. The whole-genomes of AG8, the rice pathogen AG1-IA and the potato pathogen AG3 were observed to be syntenic and co-linear. Genes and functions putatively relevant to pathogenicity were highlighted by comparing AG8 to known pathogenicity genes, orthology databases spanning 197 phytopathogenic taxa and AG1-IA. We also observed SNP-level "hypermutation" of CpG dinucleotides to TpG between AG8 nuclei, with similarities to repeat-induced point mutation (RIP). Interestingly, gene-coding regions were widely affected along with repetitive DNA, which has not been previously observed for RIP in mononuclear fungi of the Pezizomycotina. The rate of heterozygous SNP mutations within this single isolate of AG8 was observed to be higher than SNP mutation rates observed across populations of most fungal species compared. Comparative analyses were combined to predict biological processes relevant to AG8 and 308 proteins with effector-like characteristics, forming a valuable resource for further study of this pathosystem. Predicted effector-like proteins had elevated levels of non-synonymous point mutations relative to synonymous mutations (dN/dS), suggesting that they may be under diversifying selection pressures. In addition, the distant relationship to sequenced necrotrophs of the Ascomycota suggests the R. solani genome sequence may prove to be a useful resource in future comparative analysis of plant pathogens. PMID:24810276

  11. Effect of Population Dynamics of Pseudomonas cepacia and Paecilomyces lilacinus on Colonization of Polyfoam Rooting Cubes by Rhizoctonia solani

    PubMed Central

    Cartwright, D. Kelly; Benson, D. M.

    1994-01-01

    Suspensions of Pseudomonas cepacia (strain 5.5B) and Paecilomyces lilacinus (isolate 6.2F) were applied to polyfoam rooting cubes for control of stem rot of poinsettia caused by Rhizoctonia solani. The populations of antagonists and colonization of rooting cubes by R. solani were monitored during a 3-week period. Colonization of cubes by R. solani was reduced in cubes treated with P. cepacia, but the population of P. cepacia decreased by as much as 97% during the test period. Increased colonization by R. solani was correlated with a decline in population of P. cepacia. P. lilacinus was more persistent than P. cepacia in cubes, with only a 21% reduction observed during the 3-week period. Colonization of the P. lilacinus-treated cubes by R. solani was significantly less than colonization of infested controls. No correlation existed between population of P. lilacinus and colonization of cubes by R. solani. PMID:16349353

  12. First Report of Web Blight of Rosemary (Rosmarinus officinalis) Caused by Rhizoctonia solani AG-1-IB in Korea

    PubMed Central

    Aktaruzzaman, Md.; Kim, Joon-Young; Afroz, Tania

    2015-01-01

    Herein, we report the first occurrence of web blight of rosemary caused by Rhizoctonia solani AG-1-IB in Gangneung, Gangwon Province, Korea, in August 2014. The leaf tissues of infected rosemary plants were blighted and white mycelial growth was seen on the stems. The fungus was isolated from diseased leaf tissue and cultured on potato dextrose agar for identification. The young hyphae had acute angular branching near the distal septum of the multinucleate cells and mature hyphal branches formed at an approximately 90° angle. This is morphologically identical to R. solani AG-1-IB, as per previous reports. rDNA-ITS sequences of the fungus were homologous to those of R. solani AG-1-IB isolates in the GenBank database with a similarity percentage of 99%, thereby confirming the identity of the causative agent of the disease. Pathogenicity of the fungus in rosemary plants was also confirmed by Koch's postulates. PMID:26190926

  13. First Report of Web Blight of Rosemary (Rosmarinus officinalis) Caused by Rhizoctonia solani AG-1-IB in Korea.

    PubMed

    Aktaruzzaman, Md; Kim, Joon-Young; Afroz, Tania; Kim, Byung-Sup

    2015-06-01

    Herein, we report the first occurrence of web blight of rosemary caused by Rhizoctonia solani AG-1-IB in Gangneung, Gangwon Province, Korea, in August 2014. The leaf tissues of infected rosemary plants were blighted and white mycelial growth was seen on the stems. The fungus was isolated from diseased leaf tissue and cultured on potato dextrose agar for identification. The young hyphae had acute angular branching near the distal septum of the multinucleate cells and mature hyphal branches formed at an approximately 90° angle. This is morphologically identical to R. solani AG-1-IB, as per previous reports. rDNA-ITS sequences of the fungus were homologous to those of R. solani AG-1-IB isolates in the GenBank database with a similarity percentage of 99%, thereby confirming the identity of the causative agent of the disease. Pathogenicity of the fungus in rosemary plants was also confirmed by Koch's postulates. PMID:26190926

  14. Interplay between Parasitism and Host Ontogenic Resistance in the Epidemiology of the Soil-Borne Plant Pathogen Rhizoctonia solani

    PubMed Central

    Delarue, Patrick; Morlière, Stéphanie; Montfort, Françoise; Hervé, Maxime R.; Poggi, Sylvain

    2014-01-01

    Spread of soil-borne fungal plant pathogens is mainly driven by the amount of resources the pathogen is able to capture and exploit should it behave either as a saprotroph or a parasite. Despite their importance in understanding the fungal spread in agricultural ecosystems, experimental data related to exploitation of infected host plants by the pathogen remain scarce. Using Rhizoctonia solani / Raphanus sativus as a model pathosystem, we have obtained evidence on the link between ontogenic resistance of a tuberizing host and (i) its susceptibility to the pathogen and (ii) after infection, the ability of the fungus to spread in soil. Based on a highly replicable experimental system, we first show that infection success strongly depends on the host phenological stage. The nature of the disease symptoms abruptly changes depending on whether infection occurred before or after host tuberization, switching from damping-off to necrosis respectively. Our investigations also demonstrate that fungal spread in soil still depends on the host phenological stage at the moment of infection. High, medium, or low spread occurred when infection was respectively before, during, or after the tuberization process. Implications for crop protection are discussed. PMID:25127238

  15. Isolation and characterization of a novel wheat cysteine-rich receptor-like kinase gene induced by Rhizoctonia cerealis

    NASA Astrophysics Data System (ADS)

    Yang, Kun; Rong, Wei; Qi, Lin; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2013-10-01

    Cysteine-rich receptor kinases (CRKs) belong to the receptor-like kinase family. Little is known about CRK genes in wheat. We isolated a wheat CRK gene TaCRK1 from Rhizoctonia cerealis-resistant wheat CI12633 based on a differentially expressed sequence identified by RNA-Sequencing (RNA-Seq) analysis. TaCRK1 was more highly expressed in CI12633 than in susceptible Wenmai 6. Transcription of TaCRK1 in wheat was induced in CI12633 after R. cerealis infection and exogenous abscisic acid (ABA) treatment. The deduced TaCRK1 protein contained a signal peptide, two DUF26 domains, a transmembrane domain, and a serine/threonine protein kinase domain. Transient expression of a green fluorescence protein fused with TaCRK1 in wheat and onion indicated that TaCRK1 may localize to plasma membranes. Characterization of TaCRK1 silencing induced by virus-mediated method in CI12633 showed that the downregulation of TaCRK1 transcript did not obviously impair resistance to R. cerealis. This study paves the way to further CRK research in wheat.

  16. Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice

    SciTech Connect

    Syuhada, O. Nurfarahana; Kalaivani, N.

    2014-09-03

    Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.

  17. Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice

    NASA Astrophysics Data System (ADS)

    Syuhada, O. Nurfarahana; Kalaivani, N.

    2014-09-01

    Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.

  18. Potential for the integration of biological and chemical control of sheath blight disease caused by Rhizoctonia solani on rice.

    PubMed

    Boukaew, Sawai; Klinmanee, Chanasirin; Prasertsan, Poonsuk

    2013-10-01

    Biological control using antagonistic microbes to minimize the use of chemical pesticides has recently become more prevalent. In an attempt to find an integrated control system for sheath blight, caused by Rhizoctonia solani in rice, Streptomyces philanthi RM-1-138, commercial formulations of Bacillus subtilis as Larminar® and B. subtilis strain NSRS 89-24+MK-007 as Biobest® and chemical fungicides including carbendazim®, validamycin®, propiconazole® and mancozeb® were applied alone and in combination with S. philanthi RM-1-138. In vitro experiments showed that all treatments tested did provide some control against mycelial growth and sclerotia production by R. solani PTRRS-9. In addition, the four chemical fungicides had no detrimental effects on S. philanthi RM-1-138 even at high concentrations (up to 100 ?g/ml). The efficacy of S. philanthi RM-1-138, the commercial formulations of B. subtilis, chemical fungicides alone or in combination with S. philanthi RM-1-138 was also tested in a greenhouse experiment against sheath blight disease on rice plants. All treatments showed some protection of rice for sheath blight by 47-60 % when carbendazim® was applied alone and up to 74 % when combined with S. philanthi RM-1-138. PMID:23653261

  19. Isolation and characterization of a novel wheat cysteine-rich receptor-like kinase gene induced by Rhizoctonia cerealis

    PubMed Central

    Yang, Kun; Rong, Wei; Qi, Lin; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2013-01-01

    Cysteine-rich receptor kinases (CRKs) belong to the receptor-like kinase family. Little is known about CRK genes in wheat. We isolated a wheat CRK gene TaCRK1 from Rhizoctonia cerealis-resistant wheat CI12633 based on a differentially expressed sequence identified by RNA-Sequencing (RNA-Seq) analysis. TaCRK1 was more highly expressed in CI12633 than in susceptible Wenmai 6. Transcription of TaCRK1 in wheat was induced in CI12633 after R. cerealis infection and exogenous abscisic acid (ABA) treatment. The deduced TaCRK1 protein contained a signal peptide, two DUF26 domains, a transmembrane domain, and a serine/threonine protein kinase domain. Transient expression of a green fluorescence protein fused with TaCRK1 in wheat and onion indicated that TaCRK1 may localize to plasma membranes. Characterization of TaCRK1 silencing induced by virus-mediated method in CI12633 showed that the downregulation of TaCRK1 transcript did not obviously impair resistance to R. cerealis. This study paves the way to further CRK research in wheat. PMID:24149340

  20. Development of a difenoconazole/propiconazole microemulsion and its antifungal activities against Rhizoctonia solani AG1-IA.

    PubMed

    Leng, Pengfei; Zhang, Zhiming; Li, Qian; Zhang, Yunsong; Zhao, Maojun; Pan, Guangtang

    2012-06-01

    According to its physical and chemical properties, the composition of difenoconazole/propiconazole microemulsion was as follows: xylene as solvent, emulsifier HSH as surfactant and methanol as cosurfactant. The optimal formulation of difenoconazole/propiconazole microemulsion was oil/SAA/water = 1/2/5 (w/w), in which the SAA consisted of emulsifier HSH and methanol with ratio of 3/2 (w/w). The cloud point of difenoconazole/propiconazole microemulsion was 70 degrees C and its effective ingredient content was 2.5% measured by High Performance Liquid Chromatography (HPLC). Its heat storage stability was studied according to the standards. The decomposition rates of the difenoconazole/propiconazole microemulsion were merely 2.45%, 2.63% respectively and met the Food and Agriculture Organization (FAO) standards of pesticide microemulsion. Investigated by Transmission Electron Microscopy (TEM) the particle size of difenoconazole/propiconazole microemulsion was 90-140 nm and its antifungal activities against Rhizoctonia solani AG1-IA were tested and compared with that of Meiyu. We found that the inhibition rates in the difenoconazole/propiconazole microemulsion treatment group were significantly higher than that of the emulsion group with the same content of effective ingredients and the study also revealed that its inhibiting ability on the formation and germination of sclerotia was significant. PMID:22822543

  1. Interplay between parasitism and host ontogenic resistance in the epidemiology of the soil-borne plant pathogen Rhizoctonia solani.

    PubMed

    Simon, Thomas E; Le Cointe, Ronan; Delarue, Patrick; Morlière, Stéphanie; Montfort, Françoise; Hervé, Maxime R; Poggi, Sylvain

    2014-01-01

    Spread of soil-borne fungal plant pathogens is mainly driven by the amount of resources the pathogen is able to capture and exploit should it behave either as a saprotroph or a parasite. Despite their importance in understanding the fungal spread in agricultural ecosystems, experimental data related to exploitation of infected host plants by the pathogen remain scarce. Using Rhizoctonia solani / Raphanus sativus as a model pathosystem, we have obtained evidence on the link between ontogenic resistance of a tuberizing host and (i) its susceptibility to the pathogen and (ii) after infection, the ability of the fungus to spread in soil. Based on a highly replicable experimental system, we first show that infection success strongly depends on the host phenological stage. The nature of the disease symptoms abruptly changes depending on whether infection occurred before or after host tuberization, switching from damping-off to necrosis respectively. Our investigations also demonstrate that fungal spread in soil still depends on the host phenological stage at the moment of infection. High, medium, or low spread occurred when infection was respectively before, during, or after the tuberization process. Implications for crop protection are discussed. PMID:25127238

  2. Mass spectrometry identification of antifungal lipopeptides from Bacillus sp. BCLRB2 against Rhizoctonia solani and Sclerotinia sclerotiorum.

    PubMed

    Elkahoui, S; Djébali, N; Karkouch, I; Ibrahim, A Hadj; Kalai, L; Bachkovel, S; Tabbene, O; Limam, F

    2014-01-01

    This work aims to characterize the bioactive molecules produced by an antagonistic Bacillus sp. strain BCLRB2 isolated from healthy leaves of olive tree against Rhizoctonia solani and Sclerotinia sclerotiorum. The bacterial strain isolated showed a high and persistent antifungal activity against the two pathogens. The free-cell supernatant showed also a high antifungal activity against R. solani and at a lower extent against S. sclerotiorum. The partial purification of the antifungal substances with methanol gradient applied to C18 column binding the Bacillus BCLRB2 culture supernatant showed that the 20% and 60% methanol fractions had a high and specific activity against S. sclerotiorum and R. solani, respectively. The mass spectrometry identification of the compounds in the fraction specifically active against S. sclerotiorum revealed the presence of bacillomycin D C16 as a major lipopeptide. The fraction specifically active against R. solani contained bacillomycin D C15 and 2 unknown lipopeptides. The 80% methanol fraction had a moderate and a broad spectrum activity against the two pathogens and consisted from two iturin D (C13 and C14) as a major lipopeptides. PMID:25272736

  3. Pathogenicity of some Rhizoctonia solaniz isolates associated with root/collar rots on the cultivars of bean in greenhouse.

    PubMed

    Bohlooli, A; Okhovvat, S M; Javan-Nikkhah, M

    2006-01-01

    One hundred and eighteen isolates of Rhizoctonia solani were gathered from infected roots and hypocotyls of bean (Phaseolus vulgaris L.) grown in the fields of Tehran Province, Iran. Two isolates of the collected samples belonged to binucleate and 81 isolates to multinucleate of R. solani. The multinucleate isolates showed different anastomosis groups as AG-4 (subg. AG-4 HGI, AG-4HGII), AG-6 and AG-2. In greenhouse, pathogenicity tests carried out on bean cv. Naz in randomized design with 4 replications and each replication (pots) with 5 seeds of bean. Infection was done with seeds of wheat which were infected to the fungus with pasteurized soil. Results showed that the highest disease severity was caused by AG-4 (Rs21) isolates, whereas AG-4 (Rs74) isolates were weakly pathogenic with 90% and 21% infection, respectively. In this test the major pathogenic isolates belonged to AG-4 and they caused seed rot and damping-off of bean and AG-6 isolates were non-pathogenic. Five isolates of the fungus with major pathogenicity (Rs7, Rs18, Rs21, Rs62 and Rs71) selected and used for the reaction with different cultivars of bean. In this test, the cultivars and lines of bean (Pinto, red, white, green) studied in factorial experiment as randomized block design with 4 replications (pots). Results showed that none of the cultivars was completely resistant, however green bean cv. Sanry and pinto cv. Shad with number 4.8 disease severities had the highest susceptibility to seed rot and damping-off and red bean cv. Goli with 2.58 had the lowest susceptibility to the infection. Reaction of the cultivars and lines to the isolates of R. solani was significantly different at 1% level. Isolates of the fungus, Rs7, Rs21 with 84%, 90% pathogenicity was more virulent than the others. PMID:17390878

  4. Effects of methamidophos on the community structure, antagonism towards Rhizoctonia solani, and phlD diversity of soil Pseudomonas.

    PubMed

    Wu, Minna; Li, Xinyu; Zhang, Huiwen; Cai, Yinghui; Zhang, Chenggang

    2010-04-01

    A microcosm incubation study using an aquic brown soil from northeast China (a Cambisol in the UN Food and Agriculture Organization FAO Soil Taxonomy) was conducted to examine the effects of different concentrations (0, 50, 150, and 250 mg kg(-1)) of methamidophos (O,S-dimethyl phosphoramidothioato) on Pseudomonas, one of the most important gram-negative bacteria in soil. Amplified ribosomal DNA restriction analysis (ARDRA) was performed to study the Pseudomonas community structure, an in vitro assay was made to test the antagonistic activity of isolated Pseudomonas strains against soil-borne Rhizoctonia solani, a major member of the pathogens highly related to soil-borne plant diseases, and special primer amplification and sequencing were performed to investigate the diversity of phlD, an essential gene in the biosynthesis of 2, 4-diacetylphloroglucinol (2, 4-DAPG), which has biocontrol activity in phlD(+)isolates. With exposure to increasing methamidophos concentrations, the total number of soil Pseudomonas ARDRA patterns decreased significantly, but with less change in the same treatments over 1, 3, and 5 weeks of incubation. The number of isolated Pseudomonas strains with antagonistic activity against R. solani as well as the diversity and appearance frequency of the strains' phlD gene also decreased with increasing concentrations of methamidophos, especially at high methamidophos concentrations. Applying methamidophos could increase the risk of soil-borne plant diseases by decreasing the diversity of the soil Pseudomonas community and the amount of R. solani antagonists, particularly those with the phlD gene. PMID:20390954

  5. EMS-treated hexaploid wheat genotype Scarlet has enhanced tolerance to the soilborne necrotrophic pathogens Rhizoctonia solani AG-8 and R. oryzae. 2009. Theor. Appl. Genet. 119(February): 293-303

    Technology Transfer Automated Retrieval System (TEKTRAN)

    R. solani AG-8 and R. oryzae cause Rhizoctonia root rot and pre-emergence damping-off, yield-limiting diseases that pose a barrier to the adoption of reduced tillage wheat production systems intended to reduce soil erosion. We report the first genetic resistance to necrotrophic root pathogens Rhizo...

  6. GalNAc/Gal-Binding Rhizoctonia solani Agglutinin Has Antiproliferative Activity in Drosophila melanogaster S2 Cells via MAPK and JAK/STAT Signaling

    PubMed Central

    Hamshou, Mohamad; Van Damme, Els J. M.; Vandenborre, Gianni; Ghesquière, Bart; Trooskens, Geert; Gevaert, Kris; Smagghe, Guy

    2012-01-01

    Rhizoctonia solani agglutinin, further referred to as RSA, is a lectin isolated from the plant pathogenic fungus Rhizoctonia solani. Previously, we reported a high entomotoxic activity of RSA towards the cotton leafworm Spodoptera littoralis. To better understand the mechanism of action of RSA, Drosophila melanogaster Schneider S2 cells were treated with different concentrations of the lectin and FITC-labeled RSA binding was examined using confocal fluorescence microscopy. RSA has antiproliferative activity with a median effect concentration (EC50) of 0.35 µM. In addition, the lectin was typically bound to the cell surface but not internalized. In contrast, the N-acetylglucosamine-binding lectin WGA and the galactose-binding lectin PNA, which were both also inhibitory for S2 cell proliferation, were internalized whereas the mannose-binding lectin GNA did not show any activity on these cells, although it was internalized. Extracted DNA and nuclei from S2 cells treated with RSA were not different from untreated cells, confirming inhibition of proliferation without apoptosis. Pre-incubation of RSA with N-acetylgalactosamine clearly inhibited the antiproliferative activity by RSA in S2 cells, demonstrating the importance of carbohydrate binding. Similarly, the use of MEK and JAK inhibitors reduced the activity of RSA. Finally, RSA affinity chromatography of membrane proteins from S2 cells allowed the identification of several cell surface receptors involved in both signaling transduction pathways. PMID:22529896

  7. Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.).

    PubMed

    Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher

    2015-01-01

    The study evaluated the comparative performance of a few microbial antagonists, organic amendments and fungicides and their integration for the management of seedling mortality (Rhizoctonia solani Kühn) and yield improvement in pea (Pisum sativum L.). Before setting the experiment in field microplots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of R. solani, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic organic amendment and an appropriate fungicide. A greenhouse pathogenicity test compared differences in seedling mortality in pea inoculated by four isolates of R. solani and identified the isolate RS10 as the most virulent one. Among the 20 isolates screened in dual culture assay on PDA, T. harzianum isolate T-3 was found to show the highest (77.22%) inhibition of the radial growth of R. solani. A complete inhibition (100.00%) of colony growth of R. solani was observed when fungicide Bavistin 50 WP and Provax-200 at the rate of 100 and 250 ppm, respectively, were used, while Provax-200 was found to be highly compatible with T. harzianum. Mustard oilcake gave maximum inhibition (60.28%) of the radial growth of R. solani at all ratios, followed by sesame oilcake and tea waste. Integration of soil treatment with T. harzianum isolate T-3 and mustard oilcake and seed treatment with Provax-200 appeared to be significantly superior in reducing seedling mortality and improving seed yield in pea in comparison to any single or dual application of them in the experimental field. The research results will help growers develop integrated disease management strategies for the control of Rhizoctonia disease in pea. The research results show the need for an integrating selective microbial antagonist, organic amendment and fungicide to achieve appropriate management of seedling mortality (R. solani) and increase of seed yield in pea. PMID:25528673

  8. Rapid Diagnosis of Soybean Seedling Blight Caused by Rhizoctonia solani and Soybean Charcoal Rot Caused by Macrophomina phaseolina Using LAMP Assays.

    PubMed

    Lu, Chenchen; Song, Bi; Zhang, HaiFeng; Wang, YuanChao; Zheng, XiaoBo

    2015-12-01

    A new method of direct detection of pathogenic fungi in infected soybean tissues has been reported here. The method rapidly diagnoses soybean seedling blight caused by Rhizoctonia solani and soybean charcoal rot caused by Macrophomina phaseolina, and features loop-mediated isothermal amplification (LAMP). The primers were designed and screened using internal transcribed spacers (ITS) as target DNAs of both pathogens. An ITS-Rs-LAMP assay for R. solani and an ITS-Mp-LAMP assay for M. phaseolina that can detect the pathogen in diseased soybean tissues in the field have been developed. Both LAMP assays efficiently amplified the target genes over 60 min at 62°C. A yellow-green color (visible to the naked eye) or intense green fluorescence (visible under ultraviolet light) was only observed in the presence of R. solani or M. phaseolina after addition of SYBR Green I. The detection limit of the ITS-Rs-LAMP assay was 10 pg ?l(-1) of genomic DNA; and that of the ITS-Mp-LAMP assay was 100 pg ?l(-1) of genomic DNA. Using the two assays described here, we successfully and rapidly diagnosed suspect diseased soybean samples collected in the field from Jiangsu and Anhui provinces. PMID:26606587

  9. The Urochloa Foliar Blight and Collar Rot Pathogen Rhizoctonia solani AG-1 IA Emerged in South America Via a Host Shift from Rice.

    PubMed

    Chavarro Mesa, Edisson; Ceresini, Paulo C; Ramos Molina, Lina M; Pereira, Danilo A S; Schurt, Daniel A; Vieira, José R; Poloni, Nadia M; McDonald, Bruce A

    2015-11-01

    The fungus Rhizoctonia solani anastomosis group (AG)-1 IA emerged in the early 1990s as an important pathogen causing foliar blight and collar rot on pastures of the genus Urochloa (signalgrass) in South America. We tested the hypothesis that this pathogen emerged following a host shift or jump as a result of geographical overlapping of host species. The genetic structure of host and regional populations of R. solani AG-1 IA infecting signalgrass, rice, and soybean in Colombia and Brazil was analyzed using nine microsatellite loci in 350 isolates to measure population differentiation and infer the pathogen reproductive system. Phylogeographical analyses based on the microsatellite loci and on three DNA sequence loci were used to infer historical migration patterns and test hypotheses about the origin of the current pathogen populations. Cross pathogenicity assays were conducted to measure the degree of host specialization in populations sampled from different hosts. The combined analyses indicate that the pathogen populations currently infecting Urochloa in Colombia and Brazil most likely originated from a population that originally infected rice. R. solani AG-1 IA populations infecting Urochloa exhibit a mixed reproductive system including both sexual reproduction and long-distance dispersal of adapted clones, most likely on infected seed. The pathogen population on Urochloa has a genetic structure consistent with a high evolutionary potential and showed evidence for host specialization. PMID:26222889

  10. Overexpression of GhWRKY27a reduces tolerance to drought stress and resistance to Rhizoctonia solani infection in transgenic Nicotiana benthamiana

    PubMed Central

    Yan, Yan; Jia, Haihong; Wang, Fang; Wang, Chen; Liu, Shuchang; Guo, Xingqi

    2015-01-01

    WRKY proteins constitute transcriptional regulators involved in various biological processes, especially in coping with diverse biotic and abiotic stresses. However, in contrast to other well-characterized WRKY groups, the functions of group III WRKY transcription factors are poorly understood in the economically important crop cotton (Gossypium hirsutum). In this study, a group III WRKY gene from cotton, GhWRKY27a, was isolated and characterized. Our data indicated that GhWRKY27a localized to the nucleus and that GhWRKY27a expression could be strongly induced by abiotic stresses, pathogen infection, and multiple defense-related signaling molecules. Virus-induced gene silencing (VIGS) of GhWRKY27a enhanced tolerance to drought stress in cotton. In contrast, GhWRKY27a overexpression in Nicotiana benthamiana markedly reduced plant tolerance to drought stress, as determined through physiological analyses of leaf water loss, survival rates, and the stomatal aperture. This susceptibility was coupled with reduced stomatal closure in response to abscisic acid and decreased expression of stress-related genes. In addition, GhWRKY27a-overexpressing plants exhibited reduced resistance to Rhizoctonia solani infection, mainly demonstrated by the transgenic lines exhibiting more severe disease symptoms, accompanied by attenuated expression of defense-related genes in N. benthamiana. Taken together, these findings indicated that GhWRKY27a functions in negative responses to drought tolerance and in resistance to R. solani infection. PMID:26483697

  11. Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA

    PubMed Central

    2009-01-01

    A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplification of 200-320 bp size products and polymorphic sequences in all markers analyzed. By direct sequencing we identified both homokaryon and heterokaryon (i.e. dikaryon) isolates at each marker. Cloning the PCR products effectively estimated the allelic phase from heterokaryotic isolates. Information content varied among markers from 0.5 to 5.9 mutations per 100 bp. Thus, the former RFLP codominant probes were successfully converted into six distinctively variable sequence-based nuclear DNA markers. Rather than discarding low polymorphism loci, the combination of these distinctively variable anonymous nuclear markers would constitute an asset for the unbiased estimate of the phylogeographical parameters such as population sizes and divergent times, providing a more reliable species history that shaped the current population structure of R. solani AG-1 IA. PMID:21637462

  12. A simple method based on laboratory inoculum and field inoculum for evaluating potato resistance to black scurf caused by Rhizoctonia solani

    PubMed Central

    Zhang, Xiao-Yu; Yu, Xiao-Xia; Yu, Zhuo; Xue, Yu-Feng; Qi, Li-Peng

    2014-01-01

    A two-step method was developed to evaluate potato resistance to black scurf caused by Rhizoctonia solani. Tuber piece inoculum was first conducted in the laboratory, which was also first reported in this study. After inoculation with pathogen discs and culture for 48 h, the necrotic spots on the inoculated potato pieces were generated and measured by the crossing method. Further evaluation was conducted through field experiments using a wheat bran inoculum method. The wheat bran inoculum was placed into the pit dispersedly and surrounded seed tubers. Each cultivar or line was subjected to five treatments of 0-, 2-, 3-, 4-, and 5-g soil inoculum. The results showed that 2–4 g of wheat bran inoculum was the optimum for identifying tuber black scurf resistance. The laboratory scores positively correlated with the incidence and severity of black scurf in the field. According to the results in the laboratory, relatively resistant cultivars could be selected for further estimation of tuber black scurf resistance in field experiments. It is a practical and effective screening method for rapid identification of resistant potato germplasm, which can reduce workload in the field, shorten time required for identification. PMID:24987302

  13. Analysis of Phaseolus vulgaris Response to Its Association with Trichoderma harzianum (ALL-42) in the Presence or Absence of the Phytopathogenic Fungi Rhizoctonia solani and Fusarium solani

    PubMed Central

    Pereira, Jackeline L.; Queiroz, Rayner M. L.; Charneau, Sébastien O.; Felix, Carlos R.; Ricart, Carlos A. O.; da Silva, Francilene Lopes; Steindorff, Andrei Stecca; Ulhoa, Cirano J.; Noronha, Eliane F.

    2014-01-01

    The present study was carried out to evaluate the ability of Trichoderma harzianum (ALL 42-isolated from Brazilian Cerrado soil) to promote common bean growth and to modulate its metabolism and defense response in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani using a proteomic approach. T. harzianum was able to promote common bean plants growth as shown by the increase in root/foliar areas and by size in comparison to plants grown in its absence. The interaction was shown to modulate the expression of defense-related genes (Glu1, pod3 and lox1) in roots of P. vulgaris. Proteomic maps constructed using roots and leaves of plants challenged or unchallenged by T. harzianum and phytopathogenic fungi showed differences. Reference gels presented differences in spot distribution (absence/presence) and relative volumes of common spots (up or down-regulation). Differential spots were identified by peptide fingerprinting MALDI-TOF mass spectrometry. A total of 48 identified spots (19 for leaves and 29 for roots) were grouped into protein functional classes. For leaves, 33%, 22% and 11% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. For roots, 17.2%, 24.1% and 10.3% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. PMID:24878929

  14. Bacillus amyloliquefaciens subsp. plantarum GR53, a potent biocontrol agent resists Rhizoctonia disease on Chinese cabbage through hormonal and antioxidants regulation.

    PubMed

    Kang, Sang-Mo; Radhakrishnan, Ramalingam; Lee, In-Jung

    2015-10-01

    The fungus Rhizoctonia solani is one of the causal agents of numerous diseases that affect crop growth and yield. The aim of this present investigation was to identify a biocontrol agent that acts against R. solani and to determine the agent's protective effect through phytohormones and antioxidant regulation in experimentally infected Chinese cabbage plants. Four rhizospheric soil bacterial isolates GR53, GR169, GR786, and GR320 were tested for their antagonistic activity against R. solani. Among these isolates, GR53 significantly suppressed fungal growth. GR53 was identified as Bacillus amyloliquefaciens subsp. plantarum by phylogenetic analysis of the 16S rDNA sequence. The biocontrol activity of B. amyloliquefaciens subsp. plantarum GR53 was tested in Chinese cabbage plants under controlled conditions. Results showed that R. solani inhibited plant growth (length, width, fresh and dry weight of leaves) by reducing chlorophyll and total phenolic content, as well as by increasing the levels of salicylic acid, jasmonic acid, abscisic acid, and DPPH scavenging activity. By regulating the levels of these compounds, the co-inoculation of B. amyloliquefaciens subsp. plantarum GR53 heightened induced systemic resistance in infected Chinese cabbage, effectively mitigating R. solani-induced damaging effects and improving plant growth. The results obtained from this study suggest that B. amyloliquefaciens subsp. plantarum GR53 is an effective biocontrol agent to prevent the damage caused by R. solani in Chinese cabbage plants. PMID:26160009

  15. The wheat AGC kinase TaAGC1 is a positive contributor to host resistance to the necrotrophic pathogen Rhizoctonia cerealis

    PubMed Central

    Zhu, Xiuliang; Yang, Kun; Wei, Xuening; Zhang, Qiaofeng; Rong, Wei; Du, Lipu; Ye, Xingguo; Qi, Lin; Zhang, Zengyan

    2015-01-01

    Considerable progress has been made in understanding the roles of AGC kinases in mammalian systems. However, very little is known about the roles of AGC kinases in wheat (Triticum aestivum). The necrotrophic fungus Rhizoctonia cerealis is the major pathogen of the destructive disease sharp eyespot of wheat. In this study, the wheat AGC kinase gene TaAGC1, responding to R. cerealis infection, was isolated, and its properties and role in wheat defence were characterized. R. cerealis-resistant wheat lines expressed TaAGC1 at higher levels than susceptible wheat lines. Sequence and phylogenetic analyses showed that the TaAGC1 protein is a serine/threonine kinase belonging to the NDR (nuclear Dbf2-related) subgroup of AGC kinases. Kinase activity assays proved that TaAGC1 is a functional kinase and the Asp-239 residue located in the conserved serine/threonine kinase domain of TaAGC1 is required for the kinase activity. Subcellular localization assays indicated that TaAGC1 localized in the cytoplasm and nucleus. Virus-induced TaAGC1 silencing revealed that the down-regulation of TaAGC1 transcripts significantly impaired wheat resistance to R. cerealis. The molecular characterization and responses of TaAGC1 overexpressing transgenic wheat plants indicated that TaAGC1 overexpression significantly enhanced resistance to sharp eyespot and reduced the accumulation of reactive oxygen species (ROS) in wheat plants challenged with R. cerealis. Furthermore, ROS-scavenging and certain defence-associated genes were up-regulated in resistant plants overexpressing TaAGC1 but down-regulated in susceptible knock-down plants. These results suggested that the kinase TaAGC1 positively contributes to wheat immunity to R. cerealis through regulating expression of ROS-related and defence-associated genes. PMID:26220083

  16. The wheat AGC kinase TaAGC1 is a positive contributor to host resistance to the necrotrophic pathogen Rhizoctonia cerealis.

    PubMed

    Zhu, Xiuliang; Yang, Kun; Wei, Xuening; Zhang, Qiaofeng; Rong, Wei; Du, Lipu; Ye, Xingguo; Qi, Lin; Zhang, Zengyan

    2015-11-01

    Considerable progress has been made in understanding the roles of AGC kinases in mammalian systems. However, very little is known about the roles of AGC kinases in wheat (Triticum aestivum). The necrotrophic fungus Rhizoctonia cerealis is the major pathogen of the destructive disease sharp eyespot of wheat. In this study, the wheat AGC kinase gene TaAGC1, responding to R. cerealis infection, was isolated, and its properties and role in wheat defence were characterized. R. cerealis-resistant wheat lines expressed TaAGC1 at higher levels than susceptible wheat lines. Sequence and phylogenetic analyses showed that the TaAGC1 protein is a serine/threonine kinase belonging to the NDR (nuclear Dbf2-related) subgroup of AGC kinases. Kinase activity assays proved that TaAGC1 is a functional kinase and the Asp-239 residue located in the conserved serine/threonine kinase domain of TaAGC1 is required for the kinase activity. Subcellular localization assays indicated that TaAGC1 localized in the cytoplasm and nucleus. Virus-induced TaAGC1 silencing revealed that the down-regulation of TaAGC1 transcripts significantly impaired wheat resistance to R. cerealis. The molecular characterization and responses of TaAGC1 overexpressing transgenic wheat plants indicated that TaAGC1 overexpression significantly enhanced resistance to sharp eyespot and reduced the accumulation of reactive oxygen species (ROS) in wheat plants challenged with R. cerealis. Furthermore, ROS-scavenging and certain defence-associated genes were up-regulated in resistant plants overexpressing TaAGC1 but down-regulated in susceptible knock-down plants. These results suggested that the kinase TaAGC1 positively contributes to wheat immunity to R. cerealis through regulating expression of ROS-related and defence-associated genes. PMID:26220083

  17. CD45-mediated signaling pathway is involved in Rhizoctonia bataticola lectin (RBL)-induced proliferation and Th1/Th2 cytokine secretion in human PBMC

    SciTech Connect

    Pujari, Radha; Eligar, Sachin M.; Kumar, Natesh; Nagre, Nagaraja N.; Inamdar, Shashikala R.; Swamy, Bale M.; Shastry, Padma

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer RBL, a potent mitogenic and complex N-glycan specific lectin binds to CD45 on PBMC. Black-Right-Pointing-Pointer RBL triggers CD45-mediated signaling involved in activation of p38MAPK and STAT-5. Black-Right-Pointing-Pointer Inhibition of CD45 PTPase signaling blocks RBL-induced ZAP70 phosphorylation. Black-Right-Pointing-Pointer RBL-CD45 mediated signaling is crucial for RBL-induced immunodulatory activities. -- Abstract: We earlier reported the mitogenic and immunostimulatory activities of Rhizoctonia bataticola lectin (RBL), purified from phytopathogenic fungus R. bataticola in human PBMC. The lectin demonstrates specificity towards glycoproteins containing complex N-glycans. Since CD45-protein tyrosine phosphatase that abundantly expresses N-glycans is important in T-cell signaling, the study aimed to investigate the involvement of CD45 in the immunomodulatory activities of RBL. Flowcytometry and confocal microscopy studies revealed that RBL exhibited binding to PBMC and colocalized with CD45. The binding was comparable in cells expressing different CD45 isoforms-RA, -RB and -RO. CD45 blocking antibody reduced the binding and proliferation of PBMC induced by RBL. CD45-PTPase inhibitor dephostatin inhibited RBL-induced proliferation, expression of CD25 and pZAP-70. RBL-induced secretion of Th1/Th2 cytokines were significantly inhibited in presence of dephostatin. Also, dephostatin blocked phosphorylation of p38MAPK and STAT-5 that was crucial for the biological functions of RBL. The study demonstrates the involvement of CD45-mediated signaling in RBL-induced PBMC proliferation and Th1/Th2 cytokine secretion through activation of p38MAPK and STAT-5.

  18. The wheat ethylene response factor transcription factor pathogen-induced ERF1 mediates host responses to both the necrotrophic pathogen Rhizoctonia cerealis and freezing stresses.

    PubMed

    Zhu, Xiuliang; Qi, Lin; Liu, Xin; Cai, Shibin; Xu, Huijun; Huang, Rongfeng; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2014-03-01

    Sharp eyespot disease (primarily caused by the pathogen Rhizoctonia cerealis) and freezing stress are important yield limitations for the production of wheat (Triticum aestivum). Here, we report new insights into the function and underlying mechanisms of an ethylene response factor (ERF) in wheat, Pathogen-Induced ERF1 (TaPIE1), in host responses to R. cerealis and freezing stresses. TaPIE1-overexpressing transgenic wheat exhibited significantly enhanced resistance to both R. cerealis and freezing stresses, whereas TaPIE1-underexpressing wheat plants were more susceptible to both stresses relative to control plants. Following both stress treatments, electrolyte leakage and hydrogen peroxide content were significantly reduced, and both proline and soluble sugar contents were elevated in TaPIE1-overexpressing wheat, whereas these physiological traits in TaPIE1-underexpressing wheat exhibited the opposite trend. Microarray and quantitative reverse transcription-polymerase chain reaction analyses of TaPIE1-overexpressing and -underexpressing wheat plants indicated that TaPIE1 activated a subset of defense- and stress-related genes. Assays of DNA binding by electrophoretic mobility shift and transient expression in tobacco (Nicotiana tabacum) showed that the GCC boxes in the promoters of TaPIE1-activated genes were essential for transactivation by TaPIE1. The transactivation activity of TaPIE1 and the expression of TaPIE1-activated defense- and stress-related genes were significantly elevated following R. cerealis, freezing, and exogenous ethylene treatments. TaPIE1-mediated responses to R. cerealis and freezing were positively modulated by ethylene biosynthesis. These data suggest that TaPIE1 positively regulates the defense responses to R. cerealis and freezing stresses by activating defense- and stress-related genes downstream of the ethylene signaling pathway and by modulating related physiological traits in wheat. PMID:24424323

  19. Mid-Infrared (MIR) and Near-Infrared (NIR) Detection of Rhizoctonia solani AG 2-2 IIIB on Barley-Based Artificial Inoculum.

    PubMed

    Webb, Kimberly M; Calderón, Francisco J

    2015-10-01

    The amount of Rhizoctonia solani in the soil and how much must be present to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities found naturally in soil and the low sensitivity of traditional serial dilution assays. We investigated the usefulness of Fourier transform mid-infrared (MIR) and near-infrared (NIR) spectroscopic properties in identifying the artificial colonization of barley grains with R. solani AG 2-2 IIIB and in detecting R. solani populations in plant tissues and inoculants. The objectives of this study were to compare the ability of traditional plating assays to NIR and MIR spectroscopies to identify R. solani in different-size fractions of colonized ground barley (used as an artificial inoculum) and to differentiate colonized from non-inoculated barley. We found that NIR and MIR spectroscopies were sensitive in resolving different barley particle sizes, with particles that were <0.25 and 0.25-0.5 mm having different spectral properties than coarser particles. Moreover, we found that barley colonized with R. solani had different MIR spectral properties than the non-inoculated samples for the larger fractions (0.5-1.0, 1.0-2.0, and >2.0 mm) of the ground barley. This colonization was confirmed using traditional plating assays. Comparisons with the spectra from pure fungal cultures and non-inoculated barley suggest that the MIR spectrum of colonized barley is different because of the consumption of C substrates by the fungus rather than because of the presence of fungal bands in the spectra of the colonized samples. We found that MIR was better than NIR spectroscopy in differentiating the colonized from the control samples. PMID:26449805

  20. Suppression subtractive hybridization and comparative expression of a pore-forming toxin and glycosyl hydrolase genes in Rhizoctonia solani during potato sprout infection.

    PubMed

    Chamoun, Rony; Samsatly, Jamil; Pakala, Suman B; Cubeta, Marc A; Jabaji, Suha

    2015-06-01

    Rhizoctonia solani is a plant pathogenic fungus that causes black scurf on tubers and stem and stolon canker on underground parts of potato plant. Early in the season, the fungus attacks germinating sprouts underground before they emerge from the soil. Damage at this stage results in delayed emergence of weakened plants with poor and uneven stands. The mechanism underlying this phenomenon has been investigated in this study by coupling a cDNA-suppression subtractive hybridization (SSH) library to differential screening to identify transcripts of R. solani that are down-regulated during infection of potato sprouts. We report on the identification of 33 unique genes with functions related to carbohydrate binding, vitamin synthesis, pathogenicity, translation, ATP and nucleic acid binding and other categories. RACE-PCR was used to clone and characterize the first full-length cDNA clones, RSENDO1 and RSGLYC1 that encode for an eukaryotic delta-endotoxin CytB protein and an intracellular glycosyl hydrolase, respectively. Quantitative real-time PCR revealed the down-regulation of RSENDO1 during infection of potato sprouts and the up-regulation of RSGLYC1 when the fungus was grown on a cellulose-based nutrient medium. In contrast, additional experiments have highlighted the down-regulation of RSENDO1 when R. solani was co-cultured with the mycoparasite Stachybotrys elegans and the bacterial antagonist Bacillus subtilis B26. These results advance our understanding of R. solani-potato interaction in subterranean parts of the plant. Such approaches could be considered in building an efficient integrated potato disease management program. PMID:25472038

  1. Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani.

    PubMed

    Chowdhury, Soumitra Paul; Uhl, Jenny; Grosch, Rita; Alquéres, Sylvia; Pittroff, Sabrina; Dietel, Kristin; Schmitt-Kopplin, Philippe; Borriss, Rainer; Hartmann, Anton

    2015-09-01

    The commercially available inoculant Bacillus amyloliquefaciens FZB42 is able to considerably reduce lettuce bottom rot caused by Rhizoctonia solani. To understand the interaction between FZB42 and R. solani in the rhizosphere of lettuce, we used an axenic system with lettuce bacterized with FZB42 and inoculated with R. solani. Confocal laser scanning microscopy showed that FZB42 could delay the initial establishment of R. solani on the plants. To show which secondary metabolites of FZB42 are produced under these in-situ conditions, we developed an ultra-high performance liquid chromatography coupled to time of flight mass spectrometry-based method and identified surfactin, fengycin, and bacillomycin D in the lettuce rhizosphere. We hypothesized that lipopeptides and polyketides play a role in enhancing the plant defense responses in addition to the direct antagonistic effect toward R. solani and used a quantitative real-time polymerase chain reaction-based assay for marker genes involved in defense signaling pathways in lettuce. A significant higher expression of PDF 1.2 observed in the bacterized plants in response to subsequent pathogen challenge showed that FZB42 could enhance the lettuce defense response toward the fungal pathogen. To identify if surfactin or other nonribosomally synthesized secondary metabolites could elicit the observed enhanced defense gene expression, we examined two mutants of FZB42 deficient in production of surfactin and the lipopetides and polyketides, by expression analysis and pot experiments. In the absence of surfactin and other nonribosomally synthesized secondary metabolites, there was no enhanced PDF 1.2-mediated response to the pathogen challenge. Pot experiment results showed that the mutants failed to reduce disease incidence in lettuce as compared with the FZB42 wild type, indicating, that surfactin as well as other nonribosomally synthesized secondary metabolites play a role in the actual disease suppression and on lettuce health. In conclusion, our study showed that nonribosomally synthesized secondary metabolites of FZB42 are actually produced in the lettuce rhizosphere and contribute to the disease suppression by mediating plant defense gene expression toward the pathogen R. solani. PMID:26011557

  2. Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR.

    PubMed

    Sturrock, Craig J; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J; Ray, Rumiana V

    2015-01-01

    Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray ?CT) and real-time PCR to study host-pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field. PMID:26157449

  3. Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR

    PubMed Central

    Sturrock, Craig J.; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J.; Ray, Rumiana V.

    2015-01-01

    Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray ?CT) and real-time PCR to study host–pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field. PMID:26157449

  4. Development of a Rhizoctonia solani AG1-IB Specific Gene Model Enables Comparative Genome Analyses between Phytopathogenic R. solani AG1-IA, AG1-IB, AG3 and AG8 Isolates

    PubMed Central

    Wibberg, Daniel; Rupp, Oliver; Blom, Jochen; Jelonek, Lukas; Kröber, Magdalena; Verwaaijen, Bart; Goesmann, Alexander; Albaum, Stefan; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2015-01-01

    Rhizoctonia solani, a soil-born plant pathogenic basidiomycetous fungus, affects various economically important agricultural and horticultural crops. The draft genome sequence for the R. solani AG1-IB isolate 7/3/14 as well as a corresponding transcriptome dataset (Expressed Sequence Tags—ESTs) were established previously. Development of a specific R. solani AG1-IB gene model based on GMAP transcript mapping within the eukaryotic gene prediction platform AUGUSTUS allowed detection of new genes and provided insights into the gene structure of this fungus. In total, 12,616 genes were recognized in the genome of the AG1-IB isolate. Analysis of predicted genes by means of different bioinformatics tools revealed new genes whose products potentially are involved in degradation of plant cell wall components, melanin formation and synthesis of secondary metabolites. Comparative genome analyses between members of different R. solani anastomosis groups, namely AG1-IA, AG3 and AG8 and the newly annotated R. solani AG1-IB genome were performed within the comparative genomics platform EDGAR. It appeared that only 21 to 28% of all genes encoded in the draft genomes of the different strains were identified as core genes. Based on Average Nucleotide Identity (ANI) and Average Amino-acid Identity (AAI) analyses, considerable sequence differences between isolates representing different anastomosis groups were identified. However, R. solani isolates form a distinct cluster in relation to other fungi of the phylum Basidiomycota. The isolate representing AG1-IB encodes significant more genes featuring predictable functions in secondary metabolite production compared to other completely sequenced R. solani strains. The newly established R. solani AG1-IB 7/3/14 gene layout now provides a reliable basis for post-genomics studies. PMID:26690577

  5. Signaling in the rice and Rhizoctonia pathosystem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight is one of the most threatening rice diseases worldwide. Presently sheath blight disease is managed by the use of chemicals integrated with compressive cultural management systems. Identification of genetic resistance and understanding of gene expressions at early interphase duri...

  6. COMPLEMENTARY PROTEOMIC AND GENETIC ANALYSES OF RICE RESPONSE TO CHALLENGE BY THE FUNGAL PATHOGEN RHIZOCTONIA SOLANI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) is considered a model crop plant due to its importance worldwide as a food source, a small diploid genome suitable for genetic and proteomic analyses, and completion of the rice genome sequence. The objective of our research was to utilize both proteomic and genetic approaches...

  7. INFLUENCE OF GLYPHOSATE ON RHIZOCTONIA AND FUSARIUM ROOT ROT IN SUGAR BEET.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study tests the effect of glyphosate application on disease severity of glyphosate resistant sugar beet and examines whether the increase in disease in fungal- or plant-mediated. In greenhouse studies of glyphosate resistant sugar beet, increased disease severity was observed following glyphosa...

  8. Optimum Timing for Spraying Out Greenbridge with Roundup to Control Rhizoctonia in Barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field experiment was conducted in 2007 in a field at the ARS Palouse Conservation Farm with a high level of both R. solani and R. oryzae. Volunteer and weeds were allowed to grow over the winter, and plots were sprayed out with Roundup at 8 wks, 6 wks, 4 wks, 2 wks, 1 wk, and 2 days before plantin...

  9. In vitro identification of cultivar responses to rice sheath blight pathogen Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this project is to identify critical genes for the control of sheath blight disease. To this end, an in vitro method to examine interactions of rice with the rice sheath blight pathogen Rhizocotnia solani was developed. The initial analysis of R. solani isolates from the Arkansas rice ...

  10. Sensitivity to a phytotoxin from Rhizoctonia solani correlates with sheath blight susceptibility in rice.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath Blight is widely regarded as one of the most important diseases of cultivated rice and germplasm improvement is essential for disease management. Genetic sources of tolerance for this disease are known, however, complex quantitative inheritance and high environmental variability make phenoty...

  11. Inoculation and Scoring Methods for Rice Sheath Blight Disease Caused by Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant resistance (R) genes provide effective protection against invading pathogens at the front line of defense. Advances in genomic technology have accelerated efforts to characterize a wide range of crop R genes from diverse and economically important crops, resulting in effective crop protection....

  12. The Evaluation of High Tannin Cotton Lines for Resistance to Rhizoctonia solani and Pythium aphanidermatum 

    E-print Network

    Kennett, Raymond Matthew

    2011-02-22

    -tasting plant polyphenols that bind and precipitate proteins. The term tannin originated from the leather industry and was used to describe substances that were capable of turning animal hide into leather; however, the term is widely applied to any large... polyphenolic compound containing sufficient hydroxyls and other suitable groups (such as carboxyls) to form strong complexes with proteins and other macromolecules. Tannins have molecular weights ranging from 500 to over 3,000. Tannins are considered...

  13. Isolation and characterization of a phytotoxin from Rhizoctonia solani, the causal agent of rice sheath blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytotoxins (Rs-toxins) produced by R. solani are known to play an important role in the pathogenesis of this fungal pathogen, but the principal components of this phytotoxin were quite different from previous studies. To isolate and characterize the bioactive components of the Rs-toxin produced by ...

  14. SUPPRESSION OF RHIZOCTONIA ROOT ROT BY STREPTOMYCES IN BRASSICA SEED MEAL-AMENDED SOIL

    E-print Network

    Cohen, Michael F.

    treatment, particularly within the organic farming community. Members of the plant family Brassicaceae The use of plant-based organic residue as soil amendments offers a realistic alternative to broad spectrum biocides for the management of soil-borne plant pathogens. Much research in the application of organic

  15. Detection, Monitoring and Management of Rhizoctonia solani AG 2-2 LP That Causes Large Patch in Zoysiagrass in Texas 

    E-print Network

    Nissen, Lorna Denise

    2015-07-20

    and environmental conditions on R. solani AG 2-2 LP activity and LP symptom development in zoysiagrass in the fall and spring, particularly in Texas. Thus, thatch/soil moisture, thatch/soil temperature, air temperature, irrigation and nitrogen levels, and chemical...

  16. Detection, Monitoring and Management of Rhizoctonia solani AG 2-2 LP That Causes Large Patch in Zoysiagrass in Texas 

    E-print Network

    Nissen, Lorna Denise

    2015-07-20

    . Others that assisted me in the field include Joopil Yang, who was our visiting scientist from South Korea from August 2011 to August 2013, and Ruben Lopez, who was our technician from January to June 2014. Matt Zidek also assisted me in the field while.... 2004). LP often occurs during the fall and spring when turfgrass is entering or exiting winter dormancy, respectively, and when the weather is generally cool and wet (Emmons 2000, Green et al. 1993, Martinez et al. 2009). Disease symptoms in the fall...

  17. Brassica Biofumigation for Management of Rice Sheath Blight caused by Rhizoctonia solani AG 1-1A 

    E-print Network

    Handiseni, Maxwell

    2015-05-01

    verticillium wilt (Verticillium dahlia) on cauliflower (Brassica oleracea var. botrytis) (Subbarao et al. 1999), Sclerotinia sclerotiorum (Smolinska and Horbowicz 1999), Verticillium dahliae (Oliver et al. 1999), take-all (Gaeumannomyces graminis) on wheat...

  18. FIRST REPORT OF DAMPING-OFF OF CANOLA CAUSED BY RHIZOCTONIA SOLANI AG 2-1 IN WASHINGTON STATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In early Sept. 2003, winter canola (Brassica napus) cv. Inca was direct-seeded into plots previously cropped with spring barley, as part of a long-term irrigated cropping systems experiment at the WSU Dryland Research Station at Lind, WA. Before planting, the plots received 80 mm of water by sprinkl...

  19. EFFECTS OF CROP ROTATIONS AND A FALL COVER CROP ON RHIZOCTONIA CANKER, BLACK SCURF, AND COMMON SCAB OF POTATO, 2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six different rotation crops (barley/clover, canola, green bean, rapeseed, soybean, and sweet corn) planted in 2-yr rotations with potato (and a continuous potato nonrotation control) were evaluated both with and without a fall cover crop of winter rye for their effects on the development of soilbor...

  20. Single Plant Selection as a Screening Method for Resistance to Rhizoctonia solani and Pythium ultimum in Cotton 

    E-print Network

    Jones, Whitney M

    2014-04-15

    and toxic effects on pests such as insects and pathogens (Cheng et al., 2007). In 2006, Ray Kennett (2006) at Texas A&M University concluded that tannin, a polyphenol often associated with plant defense compounds, production along with other defense... selection was possible (Kennett, 2009). Kennett evaluated the effect of plant defense polyphenols in cotton, called tannins, on resistance. These compounds are considered to be an essential plant defense mechanism against disease and insects (Levin, 1973...

  1. Registration of SR98 sugar beet germplasm with resistances to Rhizoctonia seedling and crown and root rot diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar beet (Beta vulgaris L.) germplasms SR98 (PI 655951) and SR98/2 (659754) are being released as potential pollinators or populations from which to select pollinators for hybrid seed production, and were developed by the USDA-ARS, at East Lansing, MI, in cooperation with the Beet Sugar Developmen...

  2. Interactions between the root pathogen Rhizoctonia solani AG-8 and acetolacetate synthase-inhibiting herbicides in barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The widespread acceptance of reduced-tillage farming in cereal cropping systems in the Pacific Northwest (PNW) of the U.S. has resulted in increased use of herbicides for weed control. However, soil residual levels of widely used imidazalone herbicides limit the cultivation barley, which is more sen...

  3. Registration of FC723 and FC723 CMS Monogerm Sugarbeet Germplasm Resistant to Rhizoctonia Root Rot and moderately Resistant to Cercospora Leaf Spot.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugarbeet (Beta vulgaris L.) germplasms FC723 and FC723CMS (Reg. nos. GP-GP-, PI 639917 and PI 639918, respectively) were developed by the USDA-ARS, at Fort Collins, Colorado, in cooperation with the Beet Sugar Development Foundation, Denver, CO. FC723 has good resistance to root-rotting strains (A...

  4. Influence of Rhizoctonia solani and Trichoderma spp. in growth of bean (Phaseolus vulgaris L.) and in the induction of plant defense-related genes

    PubMed Central

    Mayo, Sara; Gutiérrez, Santiago; Malmierca, Monica G.; Lorenzana, Alicia; Campelo, M. Piedad; Hermosa, Rosa; Casquero, Pedro A.

    2015-01-01

    Many Trichoderma species are well-known for their ability to promote plant growth and defense. We study how the interaction of bean plants with R. solani and/or Trichoderma affect the plants growth and the level of expression of defense-related genes. Trichoderma isolates were evaluated in vitro for their potential to antagonize R. solani. Bioassays were performed in climatic chambers and development of the plants was evaluated. The effect of Trichoderma treatment and/or R. solani infection on the expression of bean defense-related genes was analyzed by real-time PCR and the production of ergosterol and squalene was quantified. In vitro growth inhibition of R. solani was between 86 and 58%. In in vivo assays, the bean plants treated with Trichoderma harzianum T019 always had an increased size respect to control and the plants treated with this isolate did not decrease their size in presence of R. solani. The interaction of plants with R. solani and/or Trichoderma affects the level of expression of seven defense-related genes. Squalene and ergosterol production differences were found among the Trichoderma isolates, T019 showing the highest values for both compounds. T. harzianum T019 shows a positive effect on the level of resistance of bean plants to R. solani. This strain induces the expression of plant defense-related genes and produces a higher level of ergosterol, indicating its ability to grow at a higher rate in the soil, which would explain its positive effects on plant growth and defense in the presence of the pathogen. PMID:26442006

  5. The Evaluation of High Tannin Cotton Lines and Their Use in Breeding for Resistance to Xanthomonas axonopodis pv. malvacearum, Pythium aphanidermatum and Rhizoctonia solani 

    E-print Network

    Kennett, Raymond

    2012-02-14

    to R. solani and while they were able to identify significant differences, no cultivar had a final survival rate of over 57%. 1.3 Tannin Tannins are astringent, bitter-tasting plant polyphenols that bind and precipitate proteins. The term tannin... originated from the leather industry and was used to describe substances that were capable of turning animal hide into leather; however, the term is applied widely to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups...

  6. Application of real-time PCR for quantification of soilborne pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soilborne pathogens can be particularly difficult to quantify. Unlike foliar diseases, symptoms caused by soilborne pathogens such as Pythium and Rhizoctonia spp. are not readily observable, making it difficult to estimate pathogen populations. Pythium and Rhizoctonia present an additional problem i...

  7. Rooting Response of Azalea Cultivars Using Hot Water Treatments to Control Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight is an annual problem on some evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. The binucleate Rhizoctonia species, which cause the disease, are spread on new shoot growth harvested for propagation. Rhizoctonia can be eli...

  8. Controlling Soilborne Pathogens in Wheat Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pacific Northwest (PNW) wheat, barley, legume and canola varieties are susceptible to broad host-range soilborne pathogens that cause Rhizoctonia root rot and Pythium root rot. Controlling Rhizoctonia and Pythium will likely require multiple strategies. My laboratory focuses on three research areas:...

  9. New Phytologist (2002) 155: 183195 www.newphytologist.com 183 Blackwell Science, Ltd

    E-print Network

    2002-01-01

    of Neottia nidus-avis, an orchid symbiotic with sebacinoids. To identify the partners each ectomycorrhiza an overlooked ectomycorrhizal group and ecto- mycorrhizal symbiosis may be common among basal lineages orchid symbionts belonging to the Rhizoctonia genus. Rhizoctonia is a large genus of asexually

  10. Do chlorophyllous orchids heterotrophically use mycorrhizal fungal carbon?

    PubMed

    Selosse, Marc-André; Martos, Florent

    2014-11-01

    The roots of orchids associate with mycorrhizal fungi, the rhizoctonias, which are considered to exchange mineral nutrients against plant carbon. The recent discovery that rhizoctonias grow endophytically in non-orchid plants raises the possibility that they provide carbon to orchids, explaining why some orchids differ in isotopic abundances from autotrophic plants. PMID:25278267

  11. Fungicide timing rules to prevent azalea web blight damage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article provides directions for timing fungicide applications to control Rhizoctonia web blight. Research has shown that many azalea cultivars are infested with the web blight pathogen (binucleate Rhizoctonia). The fungus lives 12 months of the year on azaleas, yet does not harm the plant most ...

  12. The latest news from biological interactions in orchids: in love,

    E-print Network

    to a polyphyletic assemblage of saprotrophic taxa called `rhizoctonias' which is specific to this family (Dearnaley). These partially or fully heterotrophic orchids do not associate with saprotrophic rhizoctonias, but with other fungal taxa that are saprotrophic or mycorrhizal on other nearby autotrophic plants (see Dearnaley et al

  13. EVALUATION OF FUNGICIDES FOR CONTROLLING BOTTOM ROT OF ICEBERG LETTUCE, 2001 AND 2002

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of fungicides such as Quadris, Pristin, Flint Rovral and Switch to the base of young lettuce plants after thinning and one week later reduced the incidence of disease caused by Rhizoctonia solani....

  14. 7 CFR 51.3416 - Classification of defects.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...cracks See Footnote No. 2 10% waste. Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25%...

  15. Relationships between potassium, chloride, and disease incidence in St. Augustinegrass and bermudagrass 

    E-print Network

    Rider, Larry Ray

    2001-01-01

    Potassium and chloride both suppressed Rhizoctonia blight in St. Augustinegrass and the two combined together as KCl was superior to K or Cl applied separately. Potassium applied as K?SO? showed little disease suppression. Increasing rates of KCl...

  16. 78 FR 76611 - Pesticide Experimental Use Permit; Notice of Receipt of Application; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-18

    ...on corn for efficacy against seedling infections of soilborne plant pathogenic fungi Fusarium, Rhizoctonia, Pythium and Colletotrichum, and to aid in suppression of late season stalk rot. This is a crop-destruct EUP. Amount of product to be used:...

  17. Spore viability bioassay, in vitro and greenhouse evaluation of six potential methyl bromide alternatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six test compounds were evaluated in vitro for their effectiveness in control of Phytophthora capsici, P. nicotianae, Pythium aphanidermatum, P. myriotylum, Sclerotinia sclerotiorum, Athelia rolfsii, Fusarium oxysporum, Colletotrichum acutatum, Rhizoctonia solani and Verticillium albo-atrum. Four o...

  18. Dose response of soilborne plant pathogens and Meloidogyne incognita to citrus-based experimental compounds.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two novel citrus-based compounds have been tested in vitro against Colletotrichum gleosporioides, Fusarium oxysporum, Sclerotinia sclerotiorum, Sclerotium rolfsii, Rhizoctonia solani, Verticillium albo-atrum, Pythium aphanidermatum, P. myriotilum, Phytophthora nicotianae and P. capsici. One of the...

  19. Sabatia campestris (Native) 13 

    E-print Network

    James R. Manhart

    2011-08-10

    Xanthomonas axonopodis pv. malvacearum(Smith), Pythium aphanidermatum(Edson) and Rhizoctonia solani(Kuhn) have all been shown to cause significant yield losses in cotton. Previous work has demonstrated that a set of high tannin cotton germplasm...

  20. Sabatia campestris (Native) 15 

    E-print Network

    James R. Manhart

    2011-08-10

    Cotton seedling disease complex (CSDC) is caused by a number of different pathogens, including Rhizoctonia solani (Kuhn), Pythium sp., Fusarium sp., Thielviopsis basicola and1Xanthomonas campestris pv. Malvacearum (Pammel). These pathogens can cause a... OF HIGH TANNIN COTTON LINES FOR RESISTANCE TO RHIZOCTONIA SOLANI AND PYTHIUM APHANIDERMATUM A Thesis by RAYMOND MATTHEW KENNETT Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

  1. Registration of four rice germplasm lines with improved resistance to sheath blight and blast diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight (ShB) and blast caused by the fungal pathogens Rhizoctonia solani and Magnaporthe oryzae, respectively, are the two most serious diseases of rice worldwide. Four rice (Oryza sativa L.) germplasm lines designated as LJRIL103 (PI 660982), LJRIL158 (PI 660983), LJRIL186 (PI 660984),...

  2. Breeding Value of the qSB9b and qSB12a QTLs in RiceBreeding Value of the qSB9b and qSB12a QTLs in Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight (SB) caused by Rhizoctonia solani Kuhn is a serious rice disease worldwide. The results of 123 TeQing-into-Lemont (TILs) showed those with introgressions containing qSB9b and/or qSB12a were among the most SB resistant TILs. TIL:615, TIL:642 and TIL:567 have consistently appeared modera...

  3. Identification of Sheath Blight Resistance QTLs in Rice Using Recombinant Inbred Line Population of Lemont X Jasmine 85

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight (RSB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice around the globe, causing severe losses in rice yield and quality annually. Major gene(s) governing the resistance to RSB have not been found in cultivated rice worldwide...

  4. EVALUATING RICE WILDE RELATIVES (ORYZA SPP.) FOR DISEASE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice wild relatives (Oryza spp.) are an important source of novel pest resistance genes, as well as tolerance to abiotic stresses and yield enhancing traits. Rice sheath blight caused by Rhizoctonia solani Kühn and leaf blast, Magnaporthe grisea (T.T. Herbert) Yaegashi & Udagawa, are major fungal d...

  5. Inhibitory effects of stilbenes on the growth of three soybean pathogens in culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of resveratrol and pterostilbene on in vitro growth of three soybean pathogens were tested to determine if these stilbenic compounds could potentially be targets to increase innate resistance in transgenic soybean plants. Growth of Macrophomina phaseolina, Rhizoctonia solani, and Sclerot...

  6. Registration of PR0401-259 and PR0650-31 Dry Bean Germplasm Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Web blight, caused by Thanatephorus cucumeris (Frank) Donk (anamorph: Rhizoctonia solani Kühn), is a serious disease in the humid tropics that reduces both yield and seed quality. Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Smith) Vauterin et al., and Bean common m...

  7. Antifungal effect of some spice hydrosols.

    PubMed

    Boyraz, Nuh; Ozcan, Musa

    2005-12-01

    The antifungal effects of rosemary, cumin, sater (savory), basil and pickling herb hydrosols were investigated against Rhizoctonia solani, Fusarium oxysporum f. sp tulipae, Botrytis cinerea and Alternaria citri. Hydrosols of sater and pickling herb showed the most relevant fungicidal activity. PMID:16243447

  8. Chapter 21. chlorine dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Submerging terminal leafy cuttings of Rhododendron L. 'Gumpo White' ('Gumpo White' azalea) in 50 °C water for 21 min was previously shown to eliminate binucleate Rhizoctonia species, the cause of azalea web blight, from plant tissues. Prior to considering commercial use of this practice, a better un...

  9. Development of a pathology toolbox for genetic and breeding for resistance to rice sheath blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate evaluation of the host response of rice plants to sheath blight disease, Rhizoctonia solani, is important for genetic studies and breeding for improved resistance. In the present study, a method to evaluate the response of a recombinant inbred mapping population, consisting of 574 F10 indiv...

  10. Molecular dynamics of interactions of rice with rice blast and sheath blight pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to develop the molecular strategies to control rice (Oryzae sativa) diseases, molecular interactions of rice with rice blast [Magnaporthe oryzae, formerly (Magnaporthe grisea] and sheath blight (Rhizoctonia solani) fungi were analyzed. The interaction of rice with M. oryzae follows a b...

  11. Cultivar Selection for Sugar Beet Root Rot Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal and bacterial root rots in sugar beet caused by Rhizoctonia solani (Rs) and Leuconostoc mesenteroides subsp. dextranicum (Lm) can lead to root yield losses greater than 50%. To reduce the impact of these root rots on sucrose loss in the field, storage, and factories, studies were conducted t...

  12. Current progress on genetic interactions of rice with rice blast and sheath blight fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Presently dozens of ri...

  13. RICE GERMPLASM CHARACTERIZED FOR R-GENES AND POPULATION STRUCTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the USA, newly introduced rice germplasm is one source of novel resistance genes to blast, Magnaporthe grisea, and sheath blight, Rhizoctonia solani, major fungal diseases of irrigated rice (Oryza sativa). Resistance to U.S. blast races was observed in 91 of approximately 1,000 newly introduced ...

  14. Analysis of rice PDR-like ABC transporter genes in sheath blight resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by Rhizoctonia solani is one of the most damaging diseases of rice worldwide. To understand the molecular mechanism of resistance, we identified 450 differentially expressed genes in a resistant rice cultivar Jasmine 85 after R. solani infection with a combination of DNA microar...

  15. Azalea Web Blight Control: Fungicide Timing in the Nursery and Hot Water Treatment of Stem Cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight is an annual problem on some evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. Multiple control strategies are being investigated to control the binucleate Rhizoctonia species that cause web blight. The disease will deve...

  16. Molecular characterization of rice wild relatives (Oryza spp.) and accelerating the development of disease resistant germplasm using microsatellite markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wild relatives of crop species are a source of unique genes for crop improvement. Sheath blight (Rhizoctonia solani Kuhn) and blast [Magnaporthe grisea (T.T. Herbert) Yaegashi & Udagawa] are the major diseases of cultivated rice (Oryza sativa L.) in the U.S. A set of 150 markers is being used to c...

  17. Efficacy of brassicaceous seed meal formulations for the control of apple replant disease in conventional and organic production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brassica tissues are often promoted as a soil amendment for control of soilborne plant diseases due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. Studies demonstrated that mechanisms operating in the control of Rhizoctonia root rot of apple in response ...

  18. MICHIGAN SUGARBEET Research & Education Advisory Council

    E-print Network

    : Variety: Spacings: Planting Date: Harvest Date: Previous Crop: Sample Date: Soil Type: Herbicides: Fertilizer: Replicated: Fungicide: TRIAL RELIABILITY: EMERGENCE: CERC. LEAF SPOT: RHIZOCTONIA: NEMATODES: QUADRIS APP: WEATHER: 0.5 1.1 NS0.6 NS 24.8 16.6 16.4 3.3 27.5 15 NS 245 STARTER FERTILIZER & BORON TRIAL

  19. MAPPING R-GENES IN RICE WILD RELATIVES (ORYZA SPP.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight caused by Rhizoctonia solani Kühn and leaf blast caused by Magnaporthe grisea (T.T. Herbert) Yaegashi & Udagawa are major fungal diseases of cultivated rice (Oryza sativa L.). Rice wild relatives (Oryza spp.) are the source of several resistance (R-) genes including those for bla...

  20. Evaluation of the USDA Rice Core Collection for sheath blight disease using micro-chamber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA rice core collection, including 1,794 accessions from 114 countries, was developed using a stratified random sampling method to represent the entire NSGC collection including over 18,000 accessions. Sheath blight (Rhizoctonia solani) is one of the most important and widely distributed disea...

  1. Efficacy of bacillus biocontrol agents for management of sheath blight and narrow brown leaf spot in organic rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic rice production has significantly increased in the U. S. over the last decade. Growers lack effective tools to manage sheath blight, caused by Rhizoctonia solani, and narrow brown leaf spot (NBLS), caused by Cercospora janseana, two major diseases affecting organic rice production. An experi...

  2. 77 FR 4903 - Trichoderma

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ...a naturally occurring fungus that is native to the...certain plant-pathogenic fungi (e.g., Rhizoctonia...development and testing of this fungus. With its petition...dose of 1.5 x 10\\8\\ colony-forming units (cfu...10\\4\\ to 10\\6\\ colony- forming units per...

  3. The multiple personalities of Streptomyces spp. from the rhizosphere of apple cultivated in brassica seed meal ameded soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brassicaceae seed meal soil amendments proved control of Rhizoctonia root rot, in part, through the proliferation of indigenous rhizosphere colonizing Streptomyces spp. Studies were conducted to assess the relative role of antibiosis and nitric oxide (NO) production in the capacity of Streptomyces ...

  4. Genome Sequence of the Plant Growth-Promoting Rhizobacterium Bacillus sp. Strain 916

    PubMed Central

    Luo, Chuping

    2012-01-01

    Bacillus sp. strain 916, isolated from the soil, showed strong activity against Rhizoctonia solani. Here, we present the high-quality draft genome sequence of Bacillus sp. strain 916. Its 3.9-Mb genome reveals a number of genes whose products are possibly involved in promotion of plant growth or antibiosis. PMID:22965091

  5. MOLECULAR AND PATHOLOGICAL CHARACTERIZATION OF RICE SHEATH BLIGHT PATHOGEN ISOLATES FROM ARKANSAS USING RDNA-INTERNAL TRANSCRIBED SPACER SEQUENCES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight, caused by Rhizoctonia solani Kühn (anastomosis group AG1-IA), is a serious disease worldwide. R. solani has a broad host range and no complete genetic resistance is available among cultivated rices. As first step to identify sheath blight resistance gene(s), molecular character...

  6. DISEASE NURSERIES...A TOOL TO EVALUATE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For over 45 years the USDA-ARS Sugar Beet Research Unit at Fort Collins, CO, has established disease nurseries to evaluate sugarbeet resistance to Cercospora Leaf Spot and Rhizoctonia Root Rot. These nurseries, designed to produce relatively uniform and severe disease pressure each year, are part o...

  7. Microbial degradation of fluometuron is influenced by Roundup WeatherMAX

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory experiments were conducted to describe the influence of glyphosate and fluometuron on soil microbial activity and to determine the effect of glyphosate on fluometuron degradation in soil and by Rhizoctonia solani. Soil and liquid medium were amended with formulated fluometuron alone or w...

  8. BIOLOGICAL CONTROL OF DAMPING-OFF IN SUGAR BEET SEEDLINGS WITH TRICHODERMA SPECIES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isolates of Trichoderma virens and other Trichoderma species are effective biocontrol agents for diseases of several crops. Control of damping-off caused by Rhizoctonia solani has been observed in a number of crop species. To test for biocontrol activity on sugar beet, Trichoderma strains were gro...

  9. BIOLOGICAL CONTROL OF SUGAR BEET DAMPING-OFF WITH TRICHODERMA SPP.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of damping-off in sugar beet seedlings with Trichoderma species. Isolates of Trichoderma virens and other Trichoderma species are effective biocontrol agents for diseases of several crops. Control of damping-off caused by Rhizoctonia solani has been observed in a number of c...

  10. PGPR and its combined use with fungicide for control of rice sheath blight in the southern U.S

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice growers heavily rely on fungicides for control of sheath blight, caused by Rhizoctonia solani, the most important rice disease in Texas and other southern rice-producing states. Excessive use of fungicides can cause a negative impact on the environment and lead to the potential development of f...

  11. Promises and challenges of genomics for rice pathology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Publically available genome sequences of Magnaporthe oryzae, Rhizoctonia solani, and Oryza sativa are being used to study host-pathogen interactions. Comparative genomic analyses on natural alleles of major resistance (R) genes and the corresponding avirulence (AVR) genes have provided new clues for...

  12. DEVELOPMENT OF MOLECULAR STRATEGIES TO CONTROL RICE SHEATH BLIGHT DISEASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about mechanisms of molecular interaction of host with the necrotrophic pathogen Rhizoctonia solani. After a detailed analysis of the pathogen population in the major rice producing state, Arkansas, the most virulent field isolate was identified among 124 characterized isolates. Th...

  13. Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soilborne potato diseases are persistent problems in potato production and alternative management practices are needed. In this research, biocontrol agents (Bacillus subtilis GB03 and Rhizoctonia solani hypovirulent isolate Rhs1A1) and compost amendments (from different source material), were evalua...

  14. Brassica cover cropping for management of sheath blight of rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight, caused by Rhizoctonia solani, is the most important disease limiting rice production in Texas and other rice-producing states. The fungal pathogen survives between crops as soilborne sclerotia and mycelium in infected plant debris. These sclerotia and colonized plant debris float on t...

  15. Multistate evaluation of Brassica cover crop, biocontrol agent, and fungicide for integrated management of sheath blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight, caused by Rhizoctonia solani, is one of the most important diseases limiting rice production in the southern rice-producing states. The fungus survives between crops as sclerotia and mycelia in infected plant debris and serves as the primary inoculum. Infection starts when sclerotia a...

  16. Volume 54 Number 2, 2011 ISSN 03345114 In collaboration with the

    E-print Network

    Symbiosis Society http://iss-symbiosis.org Noël Bernard (1874 - 1911) #12;Noël Bernard (1874­1911): orchids. Keywords Evolution . Mycorrhizae . Orchids . Protocorm . Rhizoctonia . Symbiosis . Tuberisation . VirulenceVolume 54 Number 2, 2011 ISSN 0334­5114 SYMBIOSIS AB 3 In collaboration with the International

  17. CONTRIBUTION OF RESIDENT SOIL MICROORGANISMS TO BRASSICACEAE SEED MEAL-INDUCED DISEASE AND WEED SUPPRESSION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brassicaceae seed meal (BSM) amendments effectively control Rhizoctonia root rot of apple and suppress weed growth in orchard soils. Pasteurization of BSM-amended soils prior to pathogen introduction eliminated disease control, suggesting the functional role of a resident biological factor. When B...

  18. DIFFERENTIAL IMPACT OF BRASSICA SPP. SEED MEAL AMENDMENTS ON FUNGAL POPULATIONS ASSOCIATED WITH ROOTS OF MALUS DOMESTICUS FROM A REPLANT ORCHARD SITE.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amending soils with Brassica spp. seed meal (BSM) is effective in reducing incidence of prominent root pathogens (e.g. Rhizoctonia solani AG5 and Pythium ultimum) in Washington state apple orchards. This effect is mediated by soil biota and varies depending upon the BSM type used and the pathogens ...

  19. Identification of quantitative trait loci (QTLs) responsible for sheath blight resistance in rice using recombinant inbred line population of Lemont X Jasmine 85

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight (RSB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice, causing severe losses in rice yield and quality annually. The major gene (s) governing the resistance to RSB have not been found in cultivated rice worldwide. However, ri...

  20. Sheath blight disease screening methods to identify resistant Oryza spp. accessions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oryza species, wild relatives of cultivated rice (O. sativa), may contain novel resistance genes to sheath blight, caused by Rhizoctonia solani Kühn, that could be used to enhance resistance to this important disease in commercial rice. Suitable greenhouse screening methods are needed to identify re...

  1. Biocontrol-based sheath blight management to reduce fungicide use on rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight (ShB) caused by Rhizoctonia solani is one of the most important rice diseases in Texas, Arkansas, Mississippi, and other southern states. The lack of complete ShB resistance in the most commonly planted varieties and the severity of this disease results in southern U.S. rice farmers ap...

  2. Introduction Proper irrigation timing can maximize sugar-

    E-print Network

    O'Laughlin, Jay

    Introduction Proper irrigation timing can maximize sugar- beet yields while minimizing disease- cially with furrow irrigation. Root diseases such as rhizomania and rhizoctonia root and crown rots will be reduced. Unnecessary irrigations can be reduced if grow- ers use information on water status at deeper

  3. Non-Fumigant management of apple replant disease in organic and conventional systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brassica tissues are often promoted as a soil amendment for control of soilborne plant diseases due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. Studies demonstrated that mechanisms operating in the control of Rhizoctonia root rot of apple in response ...

  4. Registration of TIL:455, TIL:514, and TIL:642, three rice germplasm lines containing introgressed sheath blight resistance alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are no genes known to provide complete resistance to rice sheath blight (SB) disease, caused by the fungal pathogen Rhizoctonia solani Kuhn. To create rice varieties resistant to this disease, breeders must combine several genes with small individual impact. Two of the most SB resistant rice ...

  5. Violet root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus causing violet root rot, Helicobasidium brebissonii (anamorph Rhizoctonia crocorum), is widely distributed in Europe and North America but is rarely of much economic importance on alfalfa. The disease has also been reported in Australia, Argentina, and Iran. The disease is characterized b...

  6. Draft Genome Sequence of Broad-Spectrum Antifungal Bacterium Burkholderia gladioli Strain NGJ1, Isolated from Healthy Rice Seeds

    PubMed Central

    Tyagi, Isha; Kumar, Rajeev; Ghosh, Srayan

    2015-01-01

    We report here the draft genome sequence of Burkholderia gladioli strain NGJ1. The strain was isolated from healthy rice seeds and exhibits broad-spectrum antifungal activity against several agriculturally important pathogens, including Rhizoctonia solani, Magnaporthe oryzae, Venturia inaequalis, and Fusarium oxysporum. PMID:26205861

  7. Developing a Bengal / O. nivara Advanced Backcross Mapping Population to Identify Sheath Blight QTL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight disease, caused by the soilborne necrotrophic fungus Rhizoctonia solani Kühn, is one of the most important diseases of cultivated rice (Oryza sativa L.). Wild relatives of rice (Oryza spp.) are a valuable source of genes for biotic and abiotic stress tolerance, and may contain nov...

  8. Root rot in sugar beet piles at harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar beet root rots are not only a concern because of reduced yields, but can also be associated with losses in storage. Our primary sugar beet root rot disease problem in the Amalgamated production area is Rhizoctonia root rot. However, this rot frequently only penetrates a short distance past t...

  9. Timing of fungicide sprays to prevent azalea web blight symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight is an annual problem on evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. Fungicides are the only approach currently used to control Rhizoctonia web blight; however, control is poor in some years because the specifics of...

  10. Increases in snap bean and soybean seedling diseases associated with a chloride salt and changes in the micro-partitioning of tap root calcium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In a series of field experiments from 1995 through 2010, the incidence of seedling diseases of snap bean and soybean caused by Rhizoctonia solani, Macrophomina phaseolina, Pythium spp., and Fusarium spp. was greater with an application of KCl than with K2SO4 applied at 93 kg K/ha. To determine if th...

  11. Rooting response of azalea cultivars to hot water treatment used for pathogen conrol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Submerging terminal leafy cuttings of Rhododendron L. 'Gumpo White' ('Gumpo White' azalea) in 50 °C water for 21 min was previously shown to eliminate binucleate Rhizoctonia species, the cause of azalea web blight, from plant tissues. Prior to considering commercial use of this practice, a better un...

  12. This article was originally published in the Encyclopedia of Virology, Volumes 15 published by Elsevier, and the attached copy is provided by Elsevier for

    E-print Network

    Baker, Timothy S.

    This article was originally published in the Encyclopedia of Virology, Volumes 1­5 published, Ochoa W F, Baker T S and Nibert M L. Partitiviruses: General Features. Encyclopedia of Virology, 5 vols of the genome of a partitivirus from the basidiomycete Rhizoctonia solani. Journal of General Virology 81: 549

  13. Confirming QTLs and finding additional loci responsible for resistance to rice sheath blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight disease (Rhizoctonia solani AG1-1AKühn) is one of the most destructive rice diseases worldwide. Utilization of host resistance is the most economical and environmentally sound strategy in managing sheath blight (ShB). Ten ShB-QTLs were previously mapped in a LJRIL population using...

  14. Cultivar selection for bacterial root rot in sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial root rot of sugar beet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States, which has frequently been found in association with Rhizoctonia root rot. To reduce the impact of bacterial root rot on sucrose loss in the field, st...

  15. The effect of Pseudomonas fluorescens strain q2-87 in pathogen inhibition and growth promotion of slash pine seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens strain Q2-87 showed significant antagonistic activity against the damping-off pathogens of slash pine (Pinus elliottii), including Rhizoctonia solani, Alternaria alternata and Fusarium oxysporum. In vitro assays showed that strain Q2-87, which has an inhibition index higher t...

  16. Rapeseed rotation, compost and biocontrol amendments reduce soilborne diseases and increase tuber yield in conventional and organic potato production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three different potential disease-suppressive management practices, including a Brassica napus (rapeseed) green manure rotation crop, a conifer-based compost amendment, and three biological control organisms (Trichoderma virens, Bacillus subtilis, and Rhizoctonia solani hypovirulent isolate Rhs1A1)...

  17. Notice of Release of FC1018, FC1019, FC1020 and FC1022 Multigerm Sugarbeet Germplasms with Multiple Disease Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FC1018 (PI 658059) has excellent resistance to root-rotting strains (AG-2-2) of Rhizoctonia solani Kühn and carries the Rz1 gene, which confers resistance to some strains of Beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania. FC1018 has shown a moderate tolerance to cercospora ...

  18. PGPR: A novel strategy for the control of rice sheath blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by Rhizoctonia solani is the most important rice disease in Texas, Arkansas, Mississippi and other southern states. Due to the lack of sheath blight resistance in most commonly planted cultivars, southern rice famers apply more than 1 million pounds of fungicides annually to co...

  19. Genetic and genomic dissection of resistance genes to the rice sheath blight pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight disease caused by the anastomosis group AG1-IA of the fungal pathogen Rhizoctonia solani is one of the most serious rice diseases in the southern US and the world. The use of fungicides is a popular but costly method to control this disease worldwide. Genetic analysis of host re...

  20. Integrated control of soilborne plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are no resistant varieties or chemical controls for the Major soilborne pathogens of wheat in the Pacific Northwest of the U.S. These diseases include Rhizoctonia root rot and bare patch (caused by R. solani and R. oryzae), Fusarium crown rot (caused by F. pseudograminearum and F. culmorum), P...

  1. IDENTIFYING NOVEL R-GENES IN RICE WILD RELATIVES WITH MICROSATELLITE MARKERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice wild relatives (Oryza spp.) are an important source of novel R(resistance)-genes for rice improvement. Rice sheath blight, caused by Rhizoctonia solani, and leaf blast, caused by Magnaporthe grisea, are major fungal diseases of cultivated rice (O. sativa) in the USA and of irrigated rice world...

  2. Improved quantification of pathogen DNA from soil using pressure cycling technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Detection and quantification of Rhizoctonia, Pythium and other soilborne pathogens are inconsistent at low pathogen populations and in hard-to-extract samples, despite use of sensitive diagnostic assays such as real-time PCR. An efficient and reproducible extraction system in which samples are subj...

  3. Development and characterization of RiceCAP QTL mapping population for sheath blight resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RiceCAP is a USDA CSREES funded project that has as one of its main objectives developing genetic markers associated with sheath blight resistance. Sheath blight, caused by Rhizoctonia solani, is an important disease of rice in the southern US. Tolerance to the disease is quantitatively inherited an...

  4. Sheath blight resistance increases with an increase of putative resistant alleles in rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight (ShB), caused by the soil-borne fungal pathogen Rhizoctonia solani Kühn, is an economically important rice disease worldwide, especially in intensive production systems. Over the past two decades, great efforts have been made to explore ShB quantitative trait loci (QTLs) by the tr...

  5. Sheath-blight resistance QTLs and in japonica rice germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight (SB), caused by Rhizoctonia solani, is one of the most serious diseases of cultivated rice (Oryza sativa L.) and genetic resistance is in demand by rice breeders. With the goal of resistance-QTL discovery in U. S. japonica breeding material, a set of 197 F1 doubled-haploid lines (DHLs)...

  6. Confirming QTLs and finding additional Loci responsible for resistance to Sheath Blight in Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight (ShB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice around the globe, causing severe losses in rice yield and quality annually. Major genes governing resistance to ShB have not been found in cultivated rice worldwide; however...

  7. RiceCAP: Sheath blight QTLs identified in two Bengal/O. nivara advanced backcross populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight disease, caused by Rhizoctonia solani, is one of the most important fungal diseases worldwide. Wild relatives of rice may contain novel genes for biotic/abiotic stress resistance lost during domestication. We identified seven moderately resistant accessions from a collection of 67...

  8. Brassica juncea seed meal particle size influences chemistry but not soil biology-based suppression of individual agents inciting apple replant disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple replant disease is incited by a pathogen complex composed of multiple fungal, oomycete and nematode species. Rhizoctonia solani AG-5 is a significant component of this complex and is suppressed via multiple mechanisms in response to Brassica juncea seed meal (SM) amendment. These mechanisms i...

  9. Identification of rice sheath blight QTLs in a Bengal/O. nivara advanced backcross population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice wild relatives contain novel genes for important biotic and abiotic stresses. Rice sheath blight disease, caused by Rhizoctonia solani, is a very important disease of rice worldwide. We screened 67 accessions from 15 Oryza species, and identified seven moderately resistant accessions. Using the...

  10. Two widespread green Neottia species (Orchidaceae) show mycorrhizal preference for Sebacinales in various habitats and ontogenetic stages.

    PubMed

    T?šitelová, Tamara; Kotilínek, Milan; Jersáková, Jana; Joly, François-Xavier; Košnar, Ji?í; Tatarenko, Irina; Selosse, Marc-André

    2015-03-01

    Plant dependence on fungal carbon (mycoheterotrophy) evolved repeatedly. In orchids, it is connected with a mycorrhizal shift from rhizoctonia to ectomycorrhizal fungi and a high natural (13)C and (15)N abundance. Some green relatives of mycoheterotrophic species show identical trends, but most of these remain unstudied, blurring our understanding of evolution to mycoheterotrophy. We analysed mycorrhizal associations and (13)C and (15)N biomass content in two green species, Neottia ovata and N. cordata (tribe Neottieae), from a genus comprising green and nongreen (mycoheterotrophic) species. Our study covered 41 European sites, including different meadow and forest habitats and orchid developmental stages. Fungal ITS barcoding and electron microscopy showed that both Neottia species associated mainly with nonectomycorrhizal Sebacinales Clade B, a group of rhizoctonia symbionts of green orchids, regardless of the habitat or growth stage. Few additional rhizoctonias from Ceratobasidiaceae and Tulasnellaceae, and ectomycorrhizal fungi were detected. Isotope abundances did not detect carbon gain from the ectomycorrhizal fungi, suggesting a usual nutrition of rhizoctonia-associated green orchids. Considering associations of related partially or fully mycoheterotrophic species such as Neottia camtschatea or N. nidus-avis with ectomycorrhizal Sebacinales Clade A, we propose that the genus Neottia displays a mycorrhizal preference for Sebacinales and that the association with nonectomycorrhizal Sebacinales Clade B is likely ancestral. Such a change in preference for mycorrhizal associates differing in ecology within the same fungal taxon is rare among orchids. Moreover, the existence of rhizoctonia-associated Neottia spp. challenges the shift to ectomycorrhizal fungi as an ancestral pre-adaptation to mycoheterotrophy in the whole Neottieae. PMID:25612936

  11. Diversity and Activity of Lysobacter Species from Disease Suppressive Soils

    PubMed Central

    Gómez Expósito, Ruth; Postma, Joeke; Raaijmakers, Jos M.; De Bruijn, Irene

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'–based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils. PMID:26635735

  12. Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

    PubMed

    Gómez Expósito, Ruth; Postma, Joeke; Raaijmakers, Jos M; De Bruijn, Irene

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils. PMID:26635735

  13. CONTROL OF SOIL-BORNE DISEASES BY DIFFERENT COMPOSTS IN POTTED VEGETABLE CROPS.

    PubMed

    Pugliese, M; Benetti, A; Gilardi, G; Gullino, M L; Garibaldi, A

    2014-01-01

    The composting process and the type and nature of wastes and raw materials influence the maturity, quality and suppressiveness of composts. Variability in disease suppression also depends on the pathosystem, on soil or substrate type, on chemical-physical conditions, like pH and moisture, and on the microbial component of compost. The aim of the research was to evaluate the suppressiveness of composts, originated from green wastes and/or municipal biowastes, and produced by different composting plants located in Europe. The composts were tested against soil-borne pathogens in greenhouse on potted plants: Fusarium oxysporum f.sp. busilici/basil, Pythium ultimum/cucumber, Rhizoctonia solani/bean. Composts were blended with a peat substrate at different dosages (10, 20 and 50% vol./vol.) 14 days before seeding or transplanting. Pythium ultimum and Rhizoctonia solani were mixed into the substrate at 0.5 g of wheat kernels L(-1) 7 days before seeding, while, in the case of Fusarium oxysporum f.sp. basilici, chlamydospores were applied at 1 x 10(4) CFU/g. Seeds of basil, cucumber and bean were sown into 2 L pots in greenhouse. The number of alive plants was counted and above ground biomass was weighed 30 days after seeding. The number of infected cucumber and basil plants was significantly reduced by increasing dosages of composts, but municipal compost was phytotoxic when applied at high dosages compared to green compost. Moreover, municipal compost increased the disease caused by Rhizoctonia solani on bean. The use of compost in substrates can be a suitable strategy for controlling soil-borne diseases on vegetable crops, but results depend on type of composts, application rates and pathosystems. PMID:26084080

  14. Draft Genome Sequence of a Plant Growth-Promoting Rhizobacterium, Serratia fonticola Strain AU-P3(3)

    PubMed Central

    Devi, Usha; Khatri, Indu; Kumar, Navinder; Kumar, Lalit; Sharma, Deepak

    2013-01-01

    Plant growth-promoting rhizobacteria (PGPR), found in the rhizospheric region of plants, not only suppress plant disease, but also directly improve plant health by improving the availability of nutrients and by providing phytostimulants. Herein, we report the high-quality genome sequence of Serratia fonticola strain AU-P3(3), a PGPR of the pea plant, which confers phosphate solubilization, indole-3-acetic acid production, ammonia production, hydrogen cyanide (HCN) production, and siderophore production and also confers activity against Rhizoctonia species. The 5.02-Mb genome sequence contains genes related to plant growth promotion and biocontrol activities. PMID:24233592

  15. Activity of Vitis vinifera Tendrils Extract Against Phytopathogenic Fungi.

    PubMed

    Fraternale, Daniele; Ricci, Donata; Verardo, Giancarlo; Gorassini, Andrea; Stocchia, Vilberto; Sestili, Piero

    2015-06-01

    The in vitro antifungal activity was determined of an ethanolic extract of Vitis vinifera L. tendrils (TVV) against ten plant pathogenic fungi, using the agar dilution method; activity was shown against all tested fungi. Fusarium species were the most sensitive with MIC values ranging from 250 to 300 ppm, while the basidiomycete fungus Rhizoctonia solani was the most resistant, with a MIC value of 500 ppm. Electrospray ionization tandem mass spectrometry (ESI-MS(n)) was used to obtain qualitative information on the main components of TVV. The high amount of polyphenolic compounds contained in TVV is likely to contribute significantly to its antifungal activity. PMID:26197546

  16. Mycorrhizal fungi isolated from native terrestrial orchids of pristine regions in Cordoba (Argentina).

    PubMed

    Fernández Di Pardo, Agustina; Chiocchio, Viviana M; Barrera, Viviana; Colombo, Roxana P; Martinez, Alicia E; Gasoni, Laura; Godeas, Alicia M

    2015-03-01

    Orchidaceae is a highly dependent group on the Rhizoctonia complex that includes Ceratorhiza, Moniliopsis, Epulorhiza and Rhizoctonia, for seed germination and the development of new orchid plants. Thus, the isolation and identification of orchid mycorrhizal fungi are important to understand the orchid-fungus relationship, which can lead to the development of efficient conservation strategies by in vivo germination of seeds from endangered orchid plants. The aim of our work was to isolate and characterize the different mycorrhizal fungi found in roots of terrestrial orchids from Cordoba (Argentina), and, to learn about the natural habit and fungal associations in the Chaco Serrano woodland pristine region. In this study, bloomed orchid root and rhizosphere soil samples were obtained in two times from Valle de Punilla during spring of 2007; samples were kept in plastic bags until processed within 48 hours, and mycorrhizal condition confirmed assessing peloton presence. A total of 23 isolates of the orchideous mycorrhizal Rhizoctonia complex were obtained. The isolates were studied based on morphological characters and ITS-rDNA sequences. Morphological characteristics as color of colonies, texture, growth rate, hyphal diameter and length and presence of sclerotia were observed on culture media. To define the number of nuclei per cell, the isolates were grown in Petri dishes containing water-agar (WA) for three days at 25 degrees C and stained with Safranine-O solution. The mycorrhizal fungi were grouped into binucleate (MSGib, 10 isolates) and multinucleate (MSGim, 13 isolates) based on morphological characteristics of the colonies. We obtained the ITS1-5.8s-ITS4 region that was amplified using primers ITSI and ITS4. Based on DNA sequencing, isolates Q23 and Q29 were found to be related to species of Ceratobasidium. Isolates Q24 and Q4 were related to the binucleated anastomosis group AG-C of Rhizoctonia sp. The rest of the isolates grouped in the Ceratobasidium clade without grouping. From our knowledge this is the first report of the asso- ciation of the AG-C testers with terrestrial orchids. A high specificity was observed in the symbiotic relationship. As the mycorrhizal fungal isolates were obtained from native orchids, they could be incorporated in conservation programes of endangered orchids in Argentina. PMID:26299131

  17. Dolichin, a new chitinase-like antifungal protein isolated from field beans (Dolichos lablab).

    PubMed

    Ye, X Y; Wang, H X; Ng, T B

    2000-03-01

    An antifungal protein, possessing a molecular weight of 28 kDa and an N-terminal sequence resembling chitinases, has been purified from the seeds of the field bean Dolichos lablab. The procedure involved extraction with aqueous buffer, affinity chromatography on Affi-gel blue gel, and ion exchange chromatography on CM-Sepharose. The protein, designated dolichin, exhibited antifungal activity against the fungi Fusarium oxysporum, Rhizoctonia solani, and Coprinus comatus. Dolichin was capable of inhibiting human immunodeficiency virus (HIV) reverse transcriptase and alpha- and beta-glucosidases which are glycohydrolases implicated in HIV infection. It had very low ribonuclease and cell-free translation-inhibitory activities. PMID:10694493

  18. Isolation and partial characterization of an antifungal protein produced by Bacillus licheniformis BS-3.

    PubMed

    Cui, Tang-Bing; Chai, Hai-Yun; Jiang, Li-Xiang

    2012-01-01

    An antifungal protein produced by Bacillus licheniformis strain BS-3 was purified to homogeneity by ammonium sulfate precipitation, DEAE-52 column chromatography and Sephadex G-75 column chromatography. The purified protein was designated as F2 protein, inhibited the growth of Aspergillus niger, Magnaporthe oryzae and Rhizoctonia solani. F2 protein was a monomer with approximately molecular weight of 31 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gave a single peak on High Performance Liquid Chromatography (HPLC). Using Rhizoctonia solani as the indicator strain, the EC50 of F2 protein was 35.82 µg/mL, displaying a higher antifungal activity in a range of pH 6.0 to pH 10.0, and at a temperature below 70 °C for 30 min. F2 protein was moderately resistant to hydrolysis by trypsin, proteinase K, after which its relative activities were 41.7% and 59.5%, respectively. F2 protein was assayed using various substrates to determine the enzymatic activities, the results showed the hydrolyzing activity on casein, however, no enzymatic activities on colloidal chitin, CM-cellulose, xylan, M. lysodeikticus, and p-nitrophenyl-N-acetylglucosaminide. PMID:22699567

  19. Biocontrol and plant growth-promoting activity of rhizobacteria from Chinese fields with contaminated soils

    PubMed Central

    Wang, Xuefei; Mavrodi, Dmitri V; Ke, Linfeng; Mavrodi, Olga V; Yang, Mingming; Thomashow, Linda S; Zheng, Na; Weller, David M; Zhang, Jibin

    2015-01-01

    The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to R.?solani, Gaeumannomyces graminis var. tritici and/or S.?sclerotiorum and representing the dominant morphotypes were assayed for PGPR activity. Seven strains contained phlD, prnD, pltC or phzF genes and produced the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin, pyoluteorin and phenazines respectively. Six strains contained acdS, which encodes 1-aminocyclopropane-1-carboxylic acid deaminase. Phylogenetic analysis of 16S rDNA and phlD, phzF and acdS genes demonstrated that some strains identified as Pseudomonas were similar to model PGPR strains Pseudomonas protegens?Pf-5, Pseudomonas chlororaphis subsp. aureofaciens 30–84 and P.?brassicacearum?Q8r1-96. Pseudomonas protegens- and P.?chlororaphis-like strains had the greatest biocontrol activity against Rhizoctonia root rot and take-all of wheat. Pseudomonas protegens and P.?brassicacearum-like strains showed the greatest promotion of canola growth. Our results indicate that strains from contaminated soils are similar to well-described PGPR found in agricultural soils worldwide. Growth-promoting rhizobacteria in polluted soils PMID:25219642

  20. Are fungi important for breaking seed dormancy in desert species? Experimental evidence in Opuntia streptacantha (Cactaceae).

    PubMed

    Delgado-Sánchez, P; Ortega-Amaro, M A; Jiménez-Bremont, J F; Flores, J

    2011-01-01

    Seeds of Opuntia spp. have physiological dormancy; they need a period of after-ripening to break dormancy, and the embryos have low growth potential. We evaluated the combined effects of seed age and presence of fungi on the testa on germination of Opuntia streptacantha, an abundant species in the Chihuahuan Desert (Mexico), assuming that older seeds have broken seed dormancy and fungi can reduce mechanical resistance to germination. In a preliminary experiment, we found no germination of 9-year-old (1998) and freshly collected (2007) seeds. However, we obtained 67% and 27% germination from 9-year-old and fresh non-sterilized seeds, respectively, and found fungi growing on the testa of all germinated seeds. Two fungal strains were isolated and identified using ribosomal internal transcribed spacer (ITS) sequence analysis: Penicillium chrysogenum and Phoma sp. In a second experiment, we inoculated seeds with strains of P. chrysogenum and Phoma sp., as well as Trichoderma koningii and binucleate Rhizoctonia (Gto17S2), to evaluate their ability to break seed dormancy. Seeds inoculated with P. chrysogenum, Phoma sp. and T. koningii had higher germination than controls for both seed ages, but germination was higher in older seeds. Scanning electron microscopy showed that these fungi eroded the funiculus, reducing its resistance. Binucleate Rhizoctonia did not lead to germination and controls had almost no germination. Our results strongly indicate that fungi are involved in breaking seed dormancy of O. streptacantha, and that the effect of fungi on seeds is species-specific. PMID:21143736

  1. Antimicrobial action effect and stability of nanosized silica hybrid Ag complex.

    PubMed

    Kim, Hwa-Jung; Park, Hae-Jun; Choi, Seong-Ho

    2011-07-01

    Nanosized silica hybrid silver complex (NSS) showing strong antifungal activity, in which nanosilver (nano-Ag) was bound to silica (SiO2) molecules, was synthesized via gamma-irradiation at room temperature. NSS was characterized via field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDXS), ultraviolet-visible (UV-Vis) spectrophotometer, and thermogravimetric analysis (TGA). The FESEM images and EDXS data showed that well-dispersed 3-to-10-nm Ag nanoparticles (core part) were loaded onto the outer parts of 5-to-20 nm SiO2 nanoparticles. The antifungal efficiency of NSS was evaluated against Rhizoctonia solani, Botrytis cinerea, and Colletotrichum gloeosporioides. In the case of Rhizoctonia solani, the growth rate was decreased typically by more than 90% at a 6 microg/ml concentration of NSS as a medium additive. The antifungal-action mechanism was investigated via transmission electron microscopy (TEM) analysis of the NSS treatment against Botrytis cinerea. The stability and antimicrobial activity of NSS were determined, using the plate culture method, from several water samples containing NSS after 7-day NSS treatment. Moreover, the NSS solution maintained stable antifungal activity for at least 24 mos. These results suggest that NSS, an environment-friendly nanomaterial, can be used as strongly effective growth inhibitor of various microorganisms, making it applicable to diverse antimicrobial-control systems. PMID:22121607

  2. Burkholderia terrae BS001 migrates proficiently with diverse fungal hosts through soil and provides protection from antifungal agents

    PubMed Central

    Nazir, Rashid; Tazetdinova, Diana I.; van Elsas, Jan Dirk

    2014-01-01

    Soil bacteria can benefit from co-occurring soil fungi in respect of the acquisition of carbonaceous nutrients released by fungal hyphae and the access to novel territories in soil. Here, we investigated the capacity of the mycosphere-isolated bacterium Burkholderia terrae BS001 to comigrate through soil along with hyphae of the soil fungi Trichoderma asperellum, Rhizoctonia solani, Fusarium oxysporum, F. oxysporum pv lini, Coniochaeta ligniaria, Phanerochaete velutina, and Phallus impudicus. We used Lyophyllum sp. strain Karsten as the reference migration-inciting fungus. Bacterial migration through presterilized soil on the extending fungal hyphae was detected with six of the seven test fungi, with only Phallus impudicus not showing any bacterial transport. Much like with Lyophyllum sp. strain Karsten, intermediate (106–108 CFU g-1 dry soil) to high (>108 CFU g-1 dry soil) strain BS001 cell population sizes were found at the hyphal migration fronts of four fungi, i.e., T. asperellum, Rhizoctonia solani, F. oxysporum and F. oxysporum pv lini, whereas for two fungi, Coniochaeta ligniaria and Phanerochaete velutina, the migration responses were retarded and population sizes were lower (103–106 CFU g-1 dry soil). Consistent with previous data obtained with the reference fungus, migration with the migration-inciting fungi occurred only in the direction of the hyphal growth front. Remarkably, Burkholderia terrae BS001 provided protection from several antifungal agents to the canonical host Lyophyllum sp. strain Karsten. Specifically, this host was protected from Pseudomonas fluorescens strain CHA0 metabolites, as well as from the anti-fungal agent cycloheximide. Similar protection by strain BS001was observed for T. asperellum, and, to a lower extent, F. oxysporum and Rhizoctonia solani. The protective effect may be related to the consistent occurrence of biofilm-like cell layers or agglomerates at the surfaces of the protected fungi. The current study represents the first report of protection of soil fungi against antagonistic agents present in the soil provided by fungal-associated Burkholderia terrae cells. PMID:25426111

  3. Isolation of a New Mexican Strain of Bacillus subtilis with Antifungal and Antibacterial Activities

    PubMed Central

    Basurto-Cadena, M. G. L.; Vázquez-Arista, M.; García-Jiménez, J.; Salcedo-Hernández, R.; Bideshi, D. K.; Barboza-Corona, J. E.

    2012-01-01

    Although several strains of B. subtilis with antifungal activity have been isolated worldwide, to date there are no published reports regarding the isolation of a native B. subtilis strain from strawberry plants in Mexico. A native bacterium (Bacillus subtilis 21) demonstrated in vitro antagonistic activity against different plant pathogenic fungi. Under greenhouse conditions, it was shown that plants infected with Rhizoctonia solani and Fusarium verticillioides and treated with B. subtilis 21 produced augment in the number of leaves per plant and an increment in the length of healthy leaves in comparison with untreated plants. In addition, B. subtilis 21 showed activity against pathogenic bacteria. Secreted proteins by B. subtilis 21 were studied, detecting the presence of proteases and bacteriocin-like inhibitor substances that could be implicated in its antagonistic activity. Chitinases and zwittermicin production could not be detected. Then, B. subtilis 21 could potentially be used to control phytopathogenic fungi that infect strawberry plants. PMID:22593682

  4. The evolution and pathogenic mechanisms of the rice sheath blight pathogen

    PubMed Central

    Zheng, Aiping; Lin, Runmao; Zhang, Danhua; Qin, Peigang; Xu, Lizhi; Ai, Peng; Ding, Lei; Wang, Yanran; Chen, Yao; Liu, Yao; Sun, Zhigang; Feng, Haitao; Liang, Xiaoxing; Fu, Rongtao; Tang, Changqing; Li, Qiao; Zhang, Jing; Xie, Zelin; Deng, Qiming; Li, Shuangcheng; Wang, Shiquan; Zhu, Jun; Wang, Lingxia; Liu, Huainian; Li, Ping

    2013-01-01

    Rhizoctonia solani is a major fungal pathogen of rice (Oryza sativa L.) that causes great yield losses in all rice-growing regions of the world. Here we report the draft genome sequence of the rice sheath blight disease pathogen, R. solani AG1 IA, assembled using next-generation Illumina Genome Analyser sequencing technologies. The genome encodes a large and diverse set of secreted proteins, enzymes of primary and secondary metabolism, carbohydrate-active enzymes, and transporters, which probably reflect an exclusive necrotrophic lifestyle. We find few repetitive elements, a closer relationship to Agaricomycotina among Basidiomycetes, and expand protein domains and families. Among the 25 candidate pathogen effectors identified according to their functionality and evolution, we validate 3 that trigger crop defence responses; hence we reveal the exclusive expression patterns of the pathogenic determinants during host infection. PMID:23361014

  5. Antifungal Substances from Streptomyces sp. A3265 Antagonistic to Plant Pathogenic Fungi.

    PubMed

    Van Minh, Nguyen; Woo, E-Eum; Kim, Ji-Yul; Kim, Dae-Won; Hwang, Byung Soon; Lee, Yoon-Ju; Lee, In-Kyoung; Yun, Bong-Sik

    2015-09-01

    In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria. PMID:26539051

  6. Role of Antagonistic Microorganisms and Organic Amendment in Stimulating the Defense System of Okra Against Root Rotting Fungi.

    PubMed

    Shafique, Hafiza Asma; Sultana, Viqar; Ara, Jehan; Ehteshamul-Haque, Syed; Athar, Mohammad

    2015-01-01

    Without application of chemical pesticides control of soilborne diseases is a great challenge. Stimulation of natural plant's defense is considered as one of the most promising alternative strategy for crop protection. Organic amendment of soil besides direct suppressing the pathogen, has been reported to have an influence on phytochemicals in plants. In the present study, Pseudomonas aeruginosa, a plant growth promoting rhizobacterium and Paecilomyces lilacinus, an egg parasite of root knot and cysts nematodes were examined individually and in combination in soil amended with cotton cake for suppressing the root rotting fungi and stimulating the synthesis of polyphenols and improving the antioxidant status in okra. Application of P. aeruginosa and P. lilacinus in soil amended with cotton cake significantly (P < 0.05) suppressed Macrophomina phaseolina, Fusarium oxysporum, and Fusarium solani with complete reduction of Rhizoctonia solani. Combine use of biocontrol agents in cotton cake amended soil showed maximum positive impact on plant growth, polyphenol concentration and antioxidant activity in okra. PMID:26373176

  7. Physiological and biochemical characterization of Trichoderma harzianum, a biological control agent against soilborne fungal plant pathogens.

    PubMed Central

    Grondona, I; Hermosa, R; Tejada, M; Gomis, M D; Mateos, P F; Bridge, P D; Monte, E; Garcia-Acha, I

    1997-01-01

    Monoconidial cultures of 15 isolates of Trichoderma harzianum were characterized on the basis of 82 morphological, physiological, and biochemical features and 99 isoenzyme bands from seven enzyme systems. The results were subjected to numerical analysis which revealed four distinct groups. Representative sequences of the internal transcribed spacer 1 (ITS 1)-ITS 2 region in the ribosomal DNA gene cluster were compared between groups confirming this distribution. The utility of the groupings generated from the morphological, physiological, and biochemical data was assessed by including an additional environmental isolate in the electrophoretic analysis. The in vitro antibiotic activity of the T. harzianum isolates was assayed against 10 isolates of five different soilborne fungal plant pathogens: Aphanomyces cochlioides, Rhizoctonia solani, Phoma betae, Acremonium cucurbitacearum, and Fusarium oxysporum f. sp. radicis lycopersici. Similarities between levels and specificities of biological activity and the numerical characterization groupings are both discussed in relation to antagonist-specific populations in known and potential biocontrol species. PMID:9251205

  8. Mn(II) and Cu(II) complexes of a bidentate Schiff's base ligand: Spectral, thermal, molecular modelling and mycological studies

    NASA Astrophysics Data System (ADS)

    Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

    2014-01-01

    Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L = 2-acetyl thiophene thiosemicarbazone and X = Cl- and NO3-]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum.

  9. Anti-microbial screening of endophytic fungi from Hypericum perforatum Linn.

    PubMed

    Zhang, Huawei; Ying, Chen; Tang, Yifei

    2014-09-01

    Anti-microbial properties of 21 endophytic fungal strains from Hypericum perforatum Linn. were evaluated against three human pathogens, Staphyloccocus aureus, Escherichia coli and Rhodotorula glutinis, and two phytopathogens, Rhizoctonia cerealis and Pyricularia grisea. The results indicated that the ethyl acetate extracts of endophytic fermentation broth had stronger anti-microbial activities than their fermentation broth. And the inhibitory effect of the endophytic extracts on human pathogens was better than those on phytopathogens. Among these endophytic fungi, strains GYLQ-10, GYLQ-24 and GYLQ-22 respectively showed the strongest activities against S. aureu, E. coli, R. glutinis. GYLQ-14 and GYLQ-22 exhibited the most pronounced effect on P. Grisea while both GYLQ-06 and GYLQ-08 had the strongest anti-microbial activities against R. cerealis. Till now, this study is the first report on the isolation of endophytic fungi from H. perforatum Linn. and their anti-microbial evaluation. PMID:25176358

  10. Fungal invasion of the rhizosphere microbiome.

    PubMed

    Chapelle, Emilie; Mendes, Rodrigo; Bakker, Peter A Hm; Raaijmakers, Jos M

    2016-01-01

    The rhizosphere is the infection court where soil-borne pathogens establish a parasitic relationship with the plant. To infect root tissue, pathogens have to compete with members of the rhizosphere microbiome for available nutrients and microsites. In disease-suppressive soils, pathogens are strongly restricted in growth by the activities of specific rhizosphere microorganisms. Here, we sequenced metagenomic DNA and RNA of the rhizosphere microbiome of sugar beet seedlings grown in a soil suppressive to the fungal pathogen Rhizoctonia solani. rRNA-based analyses showed that Oxalobacteraceae, Burkholderiaceae, Sphingobacteriaceae and Sphingomonadaceae were significantly more abundant in the rhizosphere upon fungal invasion. Metatranscriptomics revealed that stress-related genes (ppGpp metabolism and oxidative stress) were upregulated in these bacterial families. We postulate that the invading pathogenic fungus induces, directly or via the plant, stress responses in the rhizobacterial community that lead to shifts in microbiome composition and to activation of antagonistic traits that restrict pathogen infection. PMID:26023875

  11. Compatible fungi, suitable medium, and appropriate developmental stage essential for stable association of Dendrobium chrysanthum.

    PubMed

    Hajong, Subarna; Kumaria, Suman; Tandon, Pramod

    2013-12-01

    Establishment of symbiotic association at the appropriate developmental stage helped maintain continued growth which is vital for the long-term ex vitro survival of the orchid. In the present study, symbiotic association was carried out using different developmental stages of Dendrobium chrysanthum and pathogenic Rhizoctonia isolates (obtained from orchids and non-orchid hosts) in different culture media. Isolate 2162 supported highest symbiotic germination on OMA-S (oat meal agar medium without nutrients?+?sucrose), whereas, stable symbiotic association with plantlets was obtained with isolate 4634 on OMA-NC (oat meal agar medium?+?cellulose). Isolate Dc-2S2 obtained from the host plant did not promote seed germination nor did it form association with protocorms or plantlets. This study, for the first time identifies a combination of compatible fungal isolate, suitable culture medium, and appropriate developmental stage at which symbiotic association in vitro can be deemed successful for the medicinally important orchid, D. chrysanthum. PMID:23553724

  12. Zoosporicidal metabolites from an endophytic fungus Cryptosporiopsis sp. of Zanthoxylum leprieurii.

    PubMed

    Talontsi, Ferdinand Mouafo; Facey, Petrea; Tatong, Michel D Kongue; Tofazzal Islam, M; Frauendorf, Holm; Draeger, Siegfried; Tiedemann, Andreas von; Laatsch, Hartmut

    2012-11-01

    Two polyketides, cryptosporiopsin A (1) and hydroxypropan-2',3'-diol orsellinate (3), and a natural cyclic pentapeptide (4), together with two known compounds were isolated from the culture of Cryptosporiopsis sp., an endophytic fungus from leaves and branches of Zanthoxylum leprieurii (Rutaceae). The structures of these metabolites were elucidated on the basis of their spectroscopic and spectrometric data. Cryptosporiopsin A and the other metabolites exhibited motility inhibitory and lytic activities against zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10-25?g/mL. In addition, the isolated compounds displayed potent inhibitory activity against mycelial growth of two other peronosporomycete phytopathogens, Pythium ultimum, Aphanomyces cochlioides and a basidiomycetous fungus Rhizoctonia solani. Weak cytotoxic activity on brine shrimp larvae was observed. PMID:22883958

  13. Antifungal Substances from Streptomyces sp. A3265 Antagonistic to Plant Pathogenic Fungi

    PubMed Central

    Van Minh, Nguyen; Woo, E-Eum; Kim, Ji-Yul; Kim, Dae-Won; Hwang, Byung Soon; Lee, Yoon-Ju; Lee, In-Kyoung

    2015-01-01

    In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria. PMID:26539051

  14. Antifungal activity of violacein purified from a novel strain of Chromobacterium sp. NIIST (MTCC 5522).

    PubMed

    Sasidharan, Anju; Sasidharan, Nishanth Kumar; Amma, Dileepkumar Bhaskaran Nair Saraswathy; Vasu, Radhakrishnan Kokkuvayil; Nataraja, Anupama Vijaya; Bhaskaran, Krishnakumar

    2015-10-01

    A novel strain of Chromobacterium sp. NIIST (MTCC 5522) producing high level of purple blue bioactive compound violacein was isolated from clay mine acidic sediment. During 24 h aerobic incubation in modified Luria Bertani medium, around 0.6 g crude violacein was produced per gram of dry weight biomass. An inexpensive method for preparing crystalline, pure violacein from crude pigment was developed (12.8 mg violacein/L) and the pure compound was characterized by different spectrometric methods. The violacein prepared was found effective against a number of plant and human pathogenic fungi and yeast species such as Cryptococcus gastricus, Trichophyton rubrum, Fusarium oxysporum, Rhizoctonia solani, Aspergillus flavus, Penicillium expansum, and Candida albicans. The best activity was recorded against Trichophyton rubrum (2 -g/ml), a human pathogen responsible for causing athlete-s foot infection. This is the first report of antifungal activity of purified violacein against pathogenic fungi and yeast. PMID:26428920

  15. A new antifungal coumarin from Clausena excavata.

    PubMed

    Kumar, Ramashish; Saha, Aniruddha; Saha, Dipanwita

    2012-01-01

    A new ?-lactone coumarin, named as excavarin-A, showing antifungal activity was isolated from the leaves of Clausena excavata by bioassay guided fractionation method. The structure was elucidated by spectroscopic data analysis and identified as 7((2E)-4(4,5-dihydro-3-methylene-2-oxo-5-furanyl)-3-methylbut-2-enyloxy) coumarin. Minimum inhibitory concentration (MIC) was determined against fifteen fungal strains pathogenic against plants and human. The least MIC was recorded against the human pathogen, Candida tropicalis and the plant pathogens Rhizoctonia solani and Sclerotinia sclerotiorum. Antifungal activities against the human pathogens, Aspergillus fumigatus and Mucor circinelloides and plant pathogens, Colletotrichum gloeosporioides, Lasiodiplodia theobromae, Fusarium oxysporum and Rhizopus stolonifer were stronger than that of the standard antimicrobials. PMID:22088496

  16. Isolation of antifungal bacteria from Japanese fermented soybeans, natto.

    PubMed

    Murata, Daichi; Sawano, Sayaka; Ohike, Tatsuya; Okanami, Masahiro; Ano, Takashi

    2013-12-01

    An inhibitory effect of a traditional Japanese fermented food, natto, was found against plant pathogens such as Rhizoctonia solani and Fusarium oxysporum, and the bacteria which showed inhibition were isolated from the natto. Among isolated bacteria, BC-1 and GAc exhibited a strong antagonistic effect in vitro against plant pathogens on an agar medium. The supernatant of bacterial culture also showed strong activity against R. solani, which meant the antimicrobial substances were produced and secreted into the medium. Both of the bacteria were estimated as Bacillus amyloliquefaciens from a partial sequence of the 16s rRNA gene. High performance liquid chromatography analysis clearly showed the production of the lipopeptide antibiotic iturin A by BC-1 and GAc. PMID:25078814

  17. Screening of endophytic bacteria against fungal plant pathogens.

    PubMed

    Ohike, Tatsuya; Makuni, Kohei; Okanami, Masahiro; Ano, Takashi

    2013-12-01

    Bacterial endophytes were found from 6 plant leaves among 35 plant leaves screened. Two of the isolated bacteria showed antagonistic activity against fungal plant pathogens. An isolate named KL1 showed the clear inihibition against plant pathogens, Fusarium oxysporum and Rhizoctonia solani, on PDA as well as TSA plate. Supernatant of the bacterial culture also showed the clear inhibition against the fungal growth on the plate and the antibiotic substance was identified as iturin A by HPLC analysis. KL1 was identified as Bacillus sp. from the 16S rRNA gene analysis. Very thin hyphae of R. solani was miccroscopically observed when the fungus was co-cultivated with KL1. PMID:25078813

  18. Chestnut green waste composting for sustainable forest management: Microbiota dynamics and impact on plant disease control.

    PubMed

    Ventorino, Valeria; Parillo, Rita; Testa, Antonino; Viscardi, Sharon; Espresso, Francesco; Pepe, Olimpia

    2016-01-15

    Making compost from chestnut lignocellulosic waste is a possible sustainable management strategy for forests that employs a high-quality renewable organic resource. Characterization of the microbiota involved in composting is essential to better understand the entire process as well as the properties of the final product. Therefore, this study investigated the microbial communities involved in the composting of chestnut residues obtained from tree cleaning and pruning. The culture-independent approach taken highlighted the fact that the microbiota varied only slightly during the process, with the exception of those of the starting substrate and mature compost. The statistical analysis indicated that most of the bacterial and fungal species in the chestnut compost persisted during composting. The dominant microbial population detected during the process belonged to genera known to degrade recalcitrant lignocellulosic materials. Specifically, we identified fungal genera, such as Penicillium, Fusarium, Cladosporium, Aspergillus and Mucor, and prokaryotic species affiliated with Bacilli, Actinobacteria, Flavobacteria and ?-Proteobacteria. The suppressive properties of compost supplements for the biocontrol of Sclerotinia minor and Rhizoctonia solani were also investigated. Compared to pure substrate, the addition of compost to the peat-based growth substrates resulted in a significant reduction of disease in tomato plants of up to 70 % or 51 % in the presence of Sclerotinia minor or Rhizoctonia solani, respectively. The obtained results were related to the presence of putative bio-control agents and plant growth-promoting rhizobacteria belonging to the genera Azotobacter, Pseudomonas, Stenotrophomonas, Bacillus, Flavobacterium, Streptomyces and Actinomyces in the chestnut compost. The composting of chestnut waste may represent a sustainable agricultural practice for disposing of lignocellulosic waste by transforming it into green waste compost that can be used to improve the fitness of agricultural plants. PMID:26496847

  19. Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.)

    PubMed Central

    Runion, G. Brett; Prior, Stephen A.; Price, Andrew J.; McElroy, J. Scott; Torbert, H. Allen

    2014-01-01

    Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotypes known to be resistant or susceptible to glyphosate herbicide were exposed to either ambient or elevated (ambient +200 ? mol mol?1) concentrations of CO2 in open top chambers. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems. Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed, several of which can be either pathogens (i.e., Alternaria, Fusarium, Rhizoctonia), aiding the decline in health of the ragweed plants, or saprophytes existing on dead plant tissues. The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves. Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds. This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. PMID:25309569

  20. Untangling above- and belowground mycorrhizal fungal networks in tropical orchids.

    PubMed

    Leake, J R; Cameron, D D

    2012-10-01

    Orchids typically depend on fungi for establishment from seeds, forming mycorrhizal associations with basidiomycete fungal partners in the polyphyletic group rhizoctonia from early stages of germination, sometimes with very high specificity. This has raised important questions about the roles of plant and fungal phylogenetics, and their habitat preferences, in controlling which fungi associate with which plants. In this issue of Molecular Ecology, Martos et al. (2012) report the largest network analysis to date for orchids and their mycorrhizal fungi, sampling a total of over 450 plants from nearly half the 150 tropical orchid species on Reunion Island, encompassing its main terrestrial and epiphytic orchid genera. The authors found a total of 95 operational taxonomic units of mycorrhizal fungi and investigated the architecture and nestedness of their bipartite networks with 73 orchid species. The most striking finding was a major ecological barrier between above- and belowground mycorrhizal fungal networks, despite both epiphytic and terrestrial orchids often associating with closely related taxa across all three major lineages of rhizoctonia fungi. The fungal partnerships of the epiphytes and terrestrial species involved a diversity of fungal taxa in a modular network architecture, with only about one in ten mycorrhizal fungi partnering orchids in both groups. In contrast, plant and fungal phylogenetics had weak or no effects on the network. This highlights the power of recently developed ecological network analyses to give new insights into controls on plant-fungal symbioses and raises exciting new hypotheses about the differences in properties and functioning of mycorrhiza in epiphytic and terrestrial orchids. PMID:23057699

  1. Communities and populations of sebacinoid basidiomycetes associated with the achlorophyllous orchid Neottia nidus-avis (L.) L.C.M. Rich. and neighbouring tree ectomycorrhizae.

    PubMed

    Selosse, Marc-André; WEIss, Michael; Jany, Jean-Luc; Tillier, Annie

    2002-09-01

    Several achlorophyllous orchids associate with ectomycorrhizal hymenomycetes deriving carbon from surrounding trees for the plant. However, this has not been shown for achlorophyllous orchids associating with species of Rhizoctonia, a complex of basal lineages of hymenomycetes that are the most common orchid partners. We analysed Neottia nidus-avis, an achlorophyllous orchid symbiotic with a Rhizoctonia, to identify its symbionts by internal transcribed spacer (ITS) sequencing. Analysis of 61 root systems from 23 French populations showed that N. nidus-avis associates highly specifically with a group of species of Sebacinaceae. Their diversity emphasizes the need for further investigations in the Sebacinaceae systematics. Sebacinoid ITS sequences were often identical within orchid populations and a trend to regional variation in symbionts was observed. Using ITS and intergenic spacer (IGS) polymorphism, we showed that each root system harboured a single species, but that several genets colonized it. However, no polymorphism of these markers was found among portions of each root: this is consistent with the putative mode of entry of the fungus, i.e. from the rhizome into roots but not repeatedly from the soil. In addition, ectomycorrhizae were always found within the N. nidus-avis root systems: 120 of the 144 ectomycorrhizae typed by ITS sequencing were colonized by a sebacinoid fungus identical in ITS sequence to the respective orchid symbiont (even for the IGS polymorphism in some cases). Because sebacinoids were demonstrated recently to be ectomycorrhizal, the orchid is likely to derive its resources from surrounding trees, a mycorrhizal cheating strategy similar to other myco-heterotrophic plants studied to date. PMID:12207732

  2. Diversity and functions of volatile organic compounds produced by Streptomyces from a disease-suppressive soil

    PubMed Central

    Cordovez, Viviane; Carrion, Victor J.; Etalo, Desalegn W.; Mumm, Roland; Zhu, Hua; van Wezel, Gilles P.; Raaijmakers, Jos M.

    2015-01-01

    In disease-suppressive soils, plants are protected from infections by specific root pathogens due to the antagonistic activities of soil and rhizosphere microorganisms. For most disease-suppressive soils, however, the microorganisms and mechanisms involved in pathogen control are largely unknown. Our recent studies identified Actinobacteria as the most dynamic phylum in a soil suppressive to the fungal root pathogen Rhizoctonia solani. Here we isolated and characterized 300 isolates of rhizospheric Actinobacteria from the Rhizoctonia-suppressive soil. Streptomyces species were the most abundant, representing approximately 70% of the isolates. Streptomyces are renowned for the production of an exceptionally large number of secondary metabolites, including volatile organic compounds (VOCs). VOC profiling of 12 representative Streptomyces isolates by SPME-GC-MS allowed a more refined phylogenetic delineation of the Streptomyces isolates than the sequencing of 16S rRNA and the house-keeping genes atpD and recA only. VOCs of several Streptomyces isolates inhibited hyphal growth of R. solani and significantly enhanced plant shoot and root biomass. Coupling of Streptomyces VOC profiles with their effects on fungal growth, pointed to VOCs potentially involved in antifungal activity. Subsequent assays with five synthetic analogs of the identified VOCs showed that methyl 2-methylpentanoate, 1,3,5-trichloro-2-methoxy benzene and the VOCs mixture have antifungal activity. In conclusion, our results point to a potential role of VOC-producing Streptomyces in disease suppressive soils and show that VOC profiling of rhizospheric Streptomyces can be used as a complementary identification tool to construct strain-specific metabolic signatures. PMID:26500626

  3. Fungal Community Structure in Disease Suppressive Soils Assessed by 28S LSU Gene Sequencing

    PubMed Central

    Penton, C. Ryan; Gupta, V. V. S. R.; Tiedje, James M.; Neate, Stephen M.; Ophel-Keller, Kathy; Gillings, Michael; Harvey, Paul; Pham, Amanda; Roget, David K.

    2014-01-01

    Natural biological suppression of soil-borne diseases is a function of the activity and composition of soil microbial communities. Soil microbe and phytopathogen interactions can occur prior to crop sowing and/or in the rhizosphere, subsequently influencing both plant growth and productivity. Research on suppressive microbial communities has concentrated on bacteria although fungi can also influence soil-borne disease. Fungi were analyzed in co-located soils ‘suppressive’ or ‘non-suppressive’ for disease caused by Rhizoctonia solani AG 8 at two sites in South Australia using 454 pyrosequencing targeting the fungal 28S LSU rRNA gene. DNA was extracted from a minimum of 125 g of soil per replicate to reduce the micro-scale community variability, and from soil samples taken at sowing and from the rhizosphere at 7 weeks to cover the peak Rhizoctonia infection period. A total of ?994,000 reads were classified into 917 genera covering 54% of the RDP Fungal Classifier database, a high diversity for an alkaline, low organic matter soil. Statistical analyses and community ordinations revealed significant differences in fungal community composition between suppressive and non-suppressive soil and between soil type/location. The majority of differences associated with suppressive soils were attributed to less than 40 genera including a number of endophytic species with plant pathogen suppression potentials and mycoparasites such as Xylaria spp. Non-suppressive soils were dominated by Alternaria, Gibberella and Penicillum. Pyrosequencing generated a detailed description of fungal community structure and identified candidate taxa that may influence pathogen-plant interactions in stable disease suppression. PMID:24699870

  4. Efficacy of microorganisms selected from compost to control soil-borne pathogens.

    PubMed

    Pugliese, M; Gullino, M L; Garibaldi, A

    2010-01-01

    Suppression of soil-borne plant pathogens with compost has been widely studied. Compost has been found to be suppressive against several soil-borne pathogens in various cropping systems. However, an increase of some diseases due to compost usage has also been observed, since compost is a product that varies considerably in chemical, physical and biotic composition, and, consequently, also in ability to suppress soil borne diseases. New opportunities in disease management can be obtained by the selection of antagonists from suppressive composts. The objective of the present work was to isolate microorganisms from a suppressive compost and to test them for their activity against soil-borne pathogens. A compost from green wastes, organic domestic wastes and urban sludge's that showed a good suppressive activity in previous trials was used as source of microorganisms. Serial diluted suspensions of compost samples were plated on five different media: selective for Fusarium sp., selective for Trichoderma sp., selective for oomycetes, potato dextrose agar (PDA) for isolation of fungi, lysogeny broth (LB) for isolation of bacteria. In total, 101 colonies were isolated from plates and tested under laboratory conditions on tomato seedlings growing on perlite medium in Petri plates infected with Fusarium oxysporum f.sp. radicis-lycopersici and compared to a commercial antagonist (Streptomyces griserovidis, Mycostop, Bioplanet). Among them, 28 showed a significant disease reduction and were assessed under greenhouse condition on three pathosystems: Fusarium oxysporum f.sp. basilica/basil, Phytophthora nicotianae/tomato and Rhizoctonia solani/bean. Fusarium spp. selected from compost generally showed a good disease control against Fusarium wilts, while only bacteria significantly controlled P. nicotianae on tomato under greenhouse conditions. None of the microorganisms was able to control the three soil-borne pathogens together, in particular Rhizoctonia solani. Results confirmed the good suppressive activity of the compost under study against soil-borne pathogens. The selection of antagonists from compost is a promising strategy for the development of new biological control agents against soil-borne pathogens. PMID:21534476

  5. Fungitoxicity of lyophilized and spray-dried garlic extracts.

    PubMed

    Tedeschi, Paola; Maietti, Annalisa; Boggian, Marisa; Vecchiati, Giorgio; Brandolini, Vincenzo

    2007-01-01

    Among the compounds discussed for anti-microbial and anti-fungal use allicin (allylthiosulfinate, diallyl disulfide-S-monoxide), an active ingredient of garlic, has attracted considerable attention. The objective of this study is to determine the antifungal activity of a local garlic ecotype (Voghiera) extracts against different pathogens. Primary screening was carried out by the agar plates technique using ethanol garlic extract at four final concentrations against the following organisms: Alternaria alternata, Aspergillus spp., Colletotrichum acutatum, Didymella bryoniae, Fusarium culmorum, Fusarium avenaceum, Fusarium gramineareum, Gliocladium roseum 47, Pythium splendens, Rhizoctonia solani, Sclerotium rolfsii, Stemphylium vesicarium, Trichoderma longibranchiatum, and Botrytis cinerea. Secondary screening was carried out using a lyophilized and a spray-dried preparation at different concentrations against the organisms selected for the high inhibition garlic effect in the primary screening and compared with the commercial fungicides mancozeb and iprodione. The best results were observed for the spray-dried garlic compound that showed a good fungicidal activity at the concentration of 1.5 g/10 mL while lyophilized garlic at the same concentration exhibited less inhibition activity against the four fungi analyzed in the second screening. PMID:17763036

  6. Bioassays guided isolation of compounds from Chaetomium globosum.

    PubMed

    Awad, N E; Kassem, H A; Hamed, M A; El-Naggar, M A A; El-Feky, A M M

    2014-06-01

    The aim of the present study was to evaluate different biological activities of the fungus Chaetomium globosum (family Chaetomiaceae). The evaluation was done through testing its antimicrobial, antioxidant and anticancer effects. C. globosum was isolated from the Cucumber soil (rhizosphere) and caused inhibition of the mycelial growth of Fusarium solani, Rhizoctonia solani and Sclerotium rolfsii in the biculture test. Petroleum ether and ethyl acetate extracts of the liquid culture of C. globosum showed potent in vitro antioxidant activity. C. globosum proved potent antibacterial activity against Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens. It also recorded significant antifungal activity against Candida albicans, F. solani, Fusarium oxysporum, R. solani and Pythium ultimum. It exerted cytotoxic effect on human hepatocellular carcinoma cell line (HepG2). Unsaponifiable and saponifiable matters of the petroleum ether extract showed the presence of hydrocarbons, sterols and fatty acids. The ethyl acetate extract showed the presence of prenisatin, chrysophanol, chrysazin, chaetoviridin A and B. The isolated secondary metabolites proved significant antioxidant and antimicrobial activity on B. subtilis, E. coli and R. solani. In conclusion, this fungus showed different biological activities. Further studies must be done to apply its use in the agricultural and medicinal field. PMID:24361402

  7. Identification of a new biocontrol gene in Trichoderma atroviride: the role of an ABC transporter membrane pump in the interaction with different plant-pathogenic fungi.

    PubMed

    Ruocco, Michelina; Lanzuise, Stefania; Vinale, Francesco; Marra, Roberta; Turrà, David; Woo, Sheridan Lois; Lorito, Matteo

    2009-03-01

    Successful biocontrol interactions often require that the beneficial microbes involved are resistant or tolerant to a variety of toxicants, including antibiotics produced by themselves or phytopathogens, plant antimicrobial compounds, and synthetic chemicals or contaminants. The ability of Trichoderma spp., the most widely applied biocontrol fungi, to withstand different chemical stresses, including those associated with mycoparasitism, is well known. In this work, we identified an ATP-binding cassette transporter cell membrane pump as an important component of the above indicated resistance mechanisms that appears to be supported by an extensive and powerful cell detoxification system. The encoding gene, named Taabc2, was cloned from a strain of Trichoderma atroviride and characterized. Its expression was found to be upregulated in the presence of pathogen-secreted metabolites, specific mycotoxins and some fungicides, and in conditions that stimulate the production in Trichoderma spp. of antagonism-related factors (toxins and enzymes). The key role of this gene in antagonism and biocontrol was demonstrated by the characterization of the obtained deletion mutants. They suffered an increased susceptibility to inhibitory compounds either secreted by pathogenic fungi or possibly produced by the biocontrol microbe itself and lost, partially or entirely, the ability to protect tomato plants from Pythium ultimum and Rhizoctonia solani attack. PMID:19245323

  8. Nonribosomal Peptides, Key Biocontrol Components for Pseudomonas fluorescens In5, Isolated from a Greenlandic Suppressive Soil

    PubMed Central

    Michelsen, Charlotte F.; Watrous, Jeramie; Glaring, Mikkel A.; Kersten, Roland; Koyama, Nobuhiro

    2015-01-01

    ABSTRACT Potatoes are cultivated in southwest Greenland without the use of pesticides and with limited crop rotation. Despite the fact that plant-pathogenic fungi are present, no severe-disease outbreaks have yet been observed. In this report, we document that a potato soil at Inneruulalik in southern Greenland is suppressive against Rhizoctonia solani Ag3 and uncover the suppressive antifungal mechanism of a highly potent biocontrol bacterium, Pseudomonas fluorescens In5, isolated from the suppressive potato soil. A combination of molecular genetics, genomics, and matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) imaging mass spectrometry (IMS) revealed an antifungal genomic island in P. fluorescens In5 encoding two nonribosomal peptides, nunamycin and nunapeptin, which are key components for the biocontrol activity by strain In5 in vitro and in soil microcosm experiments. Furthermore, complex microbial behaviors were highlighted. Whereas nunamycin was demonstrated to inhibit the mycelial growth of R. solani Ag3, but not that of Pythium aphanidermatum, nunapeptin instead inhibited P. aphanidermatum but not R. solani Ag3. Moreover, the synthesis of nunamycin by P. fluorescens In5 was inhibited in the presence of P. aphanidermatum. Further characterization of the two peptides revealed nunamycin to be a monochlorinated 9-amino-acid cyclic lipopeptide with similarity to members of the syringomycin group, whereas nunapeptin was a 22-amino-acid cyclic lipopeptide with similarity to corpeptin and syringopeptin. PMID:25784695

  9. Molecular and phenotypic characterization of Sebacina vermifera strains associated with orchids, and the description of Piriformospora williamsii sp. nov.

    PubMed

    Basiewicz, Magdalena; Weiss, Michael; Kogel, Karl-Heinz; Langen, Gregor; Zorn, Holger; Zuccaro, Alga

    2012-02-01

    Sebacinales was described in 2004 and is currently recognized as the earliest diverging lineage of mycorrhizal Basidiomycota. In addition, recent research has demonstrated that no other known fungal order harbours a broader spectrum of mycorrhizal types. Yet because of the character poor morphology of these inconspicuous fungi, a reliable systematic framework for Sebacinales is still out of reach. In order to increase the body of comparative data on Sebacinales, we followed a polyphasic approach using a sampling of seven diverse Sebacinales strains, including several isolates of Australian orchid mycorrhizae, Piriformospora indica, and a multinucleate rhizoctonia isolated from a pot culture of Glomus fasciculatum (Williams 1985) with clover. We performed molecular phylogenetic analyses from candidate barcoding regions [rDNA: internal transcribed spacer (ITS)1-5.8-ITS2, 28S; translation elongation factor 1-? (TEF)], enzymatic profiling, genome size estimation by quantitative polymerase chain reaction (PCR), and karyotype analysis using pulsed field gel electrophoresis. Here, we report significant differences in the physiological and molecular parameters inferred from these morphologically very similar strains. Particularly, our results indicate that intron sequences of the TEF gene are useful markers for Sebacinales at the species level. As a first taxonomic consequence, we describe Piriformospora williamsii as a new member of the so far monotypic genus Piriformospora and show that this genus contains still undescribed species that were recently discovered as endophytes of field-collected specimens of Anthyllis, Medicago, and Lolium in Germany. PMID:22289766

  10. Naturally produced citral can significantly inhibit normal physiology and induce cytotoxicity on Magnaporthe grisea.

    PubMed

    Li, Rong-Yu; Wu, Xiao-Mao; Yin, Xian-Hui; Long, You-Hua; Li, Ming

    2015-02-01

    Given the importance of finding alternatives to synthetic fungicides, the antifungal effects of natural product citral on six plant pathogenic fungi (Magnaporthe grisea, Gibberella zeae, Fusarium oxysporum, Valsa mali, Botrytis cinerea, and Rhizoctonia solani) were determined. Mycelial growth rate results showed that citral possessed high antifungal activities on those test fungi with EC50 values ranging from 39.52 to 193.00?µg/mL, which had the highest inhibition rates against M. grisea. Further action mechanism of citral on M. grisea was carried out. Citral treatment was found to alter the morphology of M. grisea hyphae by causing a loss of cytoplasm and distortion of mycelia. Moreover, citral was able to induce an increase in chitinase activity in M. grisea, indicating disruption of the cell wall. These results indicate that citral may act by disrupting cell wall integrity and membrane permeability, thus resulting in physiology changes and causing cytotoxicity. Importantly, the inhibitory effect of citral on M. grisea appears to be associated with its effects on mycelia reducing sugar, soluble protein, chitinase activity, pyruvate content, and malondialdehyde content. PMID:25752425

  11. Isolation, selection, and characterization of beneficial rhizobacteria from pea, lentil, and chickpea grown in western Canada.

    PubMed

    Hynes, Russell K; Leung, Grant C Y; Hirkala, Danielle L M; Nelson, Louise M

    2008-04-01

    The use of beneficial soil microorganisms as agricultural inputs for improved crop production requires selection of rhizosphere-competent microorganisms with plant growth-promoting attributes. A collection of 563 bacteria originating from the roots of pea, lentil, and chickpea grown in Saskatchewan was screened for several plant growth-promoting traits, for suppression of legume fungal pathogens, and for plant growth promotion. Siderophore production was detected in 427 isolates (76%), amino-cyclopropane-1-carboxylic acid (ACC) deaminase activity in 29 isolates (5%), and indole production in 38 isolates (7%). Twenty-six isolates (5%) suppressed the growth of Pythium sp. strain p88-p3, 40 isolates (7%) suppressed the growth of Fusarium avenaceum, and 53 isolates (9%) suppressed the growth of Rhizoctonia solani CKP7. Seventeen isolates (3%) promoted canola root elongation in a growth pouch assay, and of these, 4 isolates promoted the growth of lentil and one isolate promoted the growth of pea. Fatty acid profile analysis and 16S rRNA sequencing of smaller subsets of the isolates that were positive for the plant growth-promotion traits tested showed that 39%-42% were members of the Pseudomonadaceae and 36%-42% of the Enterobacteriaceae families. Several of these isolates may have potential for development as biofertilizers or biopesticides for western Canadian legume crops. PMID:18388997

  12. Cow dung extract: a medium for the growth of pseudomonads enhancing their efficiency as biofertilizer and biocontrol agent in rice.

    PubMed

    Srivastava, Rashmi; Aragno, Michel; Sharma, A K

    2010-09-01

    Some pseudomands are being utilized as biofertilizers and biopesticides because of their role in plant growth promotion and plant protection against root parasites, respectively. Two strains of Pseudomonas, P. jessenii LHRE62 and P. synxantha HHRE81, recovered from wheat rhizosphere, have shown their potential in field bioinoculation tests under rice-wheat and pulse-wheat rotation systems. Normally, pseudomonads are cultivated on synthetic media-like King's B and used for inoculation on seeds/soil drench with talcum or charcoal as carrier material. Cow dung is being used for different purposes from the ancient time and has a significant role in crop growth because of the content in humic compounds and fertilizing bioelements available in it. Here, cow dung extract was tested as a growth medium for strains LHRE62 and HHRE81, in comparison with growth in King's B medium. The log phase was delayed by 2 h as compared to growth in King's B medium. The bacterial growth yield, lower in plain cow dung extract as compared to King's B medium, was improved upon addition of different carbon substrates. Growth of rice var. Pant Dhan 4 in pot cultures was increased using liquid formulation of cow dung extract and bacteria as foliar spray, compared to their respective controls. Biocontrol efficacy of the bioagents was assessed by challenging rice crop with Rhizoctonia solani, a sheath blight pathogen. The growth promotion and biocontrol efficiencies were more pronounced in the case of mixed inocula of strains LHRE62 and HHRE81. PMID:23100852

  13. Arbuscular mycorrhizal fungal spores host bacteria that affect nutrient biodynamics and biocontrol of soil-borne plant pathogens

    PubMed Central

    Cruz, Andre Freire; Ishii, Takaaki

    2012-01-01

    Summary The aim of this research was to isolate and characterize bacteria from spores of arbuscular mycorrhizal fungi (AMF). We designated these bacteria ‘probable endobacteria’ (PE). Three bacterial strains were isolated from approximately 500 spores of Gigaspora margarita (Becker and Hall) using a hypodermic needle (diameter, 200??m). The bacteria were identified by morphological methods and on the basis of ribosomal gene sequences as Bacillus sp. (KTCIGM01), Bacillus thuringiensis (KTCIGM02), and Paenibacillus rhizospherae (KTCIGM03). We evaluated the effect of these probable endobacteria on antagonistic activity to the soil-borne plant pathogens (SBPPs) Fusarium oxysporum f. sp. lactucae MAFF 744088, Rosellinia necatrix, Rhizoctonia solani MAFF 237426, and Pythium ultimum NBRC 100123. We also tested whether these probable endobacteria affected phosphorus solubilization, ethylene production, nitrogenase activity (NA), and stimulation of AMF hyphal growth. In addition, fresh samples of spores and hyphae were photographed using an in situ scanning electron microscope (SEM) (Quanta 250FEG; FEI Co., Japan). Bacterial aggregates (BAs), structures similar to biofilms, could be detected on the surface of hyphae and spores. We demonstrate that using extraction with an ultrathin needle, it is possible to isolate AMF-associated bacterial species that are likely derived from inside the fungal spores. PMID:23213368

  14. Arbuscular mycorrhizal fungal spores host bacteria that affect nutrient biodynamics and biocontrol of soil-borne plant pathogens.

    PubMed

    Cruz, Andre Freire; Ishii, Takaaki

    2012-01-15

    The aim of this research was to isolate and characterize bacteria from spores of arbuscular mycorrhizal fungi (AMF). We designated these bacteria 'probable endobacteria' (PE). Three bacterial strains were isolated from approximately 500 spores of Gigaspora margarita (Becker and Hall) using a hypodermic needle (diameter, 200??m). The bacteria were identified by morphological methods and on the basis of ribosomal gene sequences as Bacillus sp. (KTCIGM01), Bacillus thuringiensis (KTCIGM02), and Paenibacillus rhizospherae (KTCIGM03). We evaluated the effect of these probable endobacteria on antagonistic activity to the soil-borne plant pathogens (SBPPs) Fusarium oxysporum f. sp. lactucae MAFF 744088, Rosellinia necatrix, Rhizoctonia solani MAFF 237426, and Pythium ultimum NBRC 100123. We also tested whether these probable endobacteria affected phosphorus solubilization, ethylene production, nitrogenase activity (NA), and stimulation of AMF hyphal growth. In addition, fresh samples of spores and hyphae were photographed using an in situ scanning electron microscope (SEM) (Quanta 250FEG; FEI Co., Japan). Bacterial aggregates (BAs), structures similar to biofilms, could be detected on the surface of hyphae and spores. We demonstrate that using extraction with an ultrathin needle, it is possible to isolate AMF-associated bacterial species that are likely derived from inside the fungal spores. PMID:23213368

  15. Biological Role of Trichoderma harzianum-Derived Platelet-Activating Factor Acetylhydrolase (PAF-AH) on Stress Response and Antagonism

    PubMed Central

    Yu, Chuanjin; Fan, Lili; Wu, Qiong; Fu, Kehe; Gao, Shigang; Wang, Meng; Gao, Jinxin; Li, Yaqian; Chen, Jie

    2014-01-01

    We investigated the properties of platelet-activating factor acetylhydrolase (PAF-AH) derived from Trichoderma harzianum. The enzyme, comprised of 572 amino acids, shares high homology with PAF-AH proteins from T. koningii and other microbial species. The optimum enzymatic activity of PAF-AH occurred at pH 6 in the absence of Ca2+ and it localized in the cytoplasm, and we observed the upregulation of PAF-AH expression in response to carbon starvation and strong heat shock. Furthermore, PAF-AH knockout transformant growth occurred more slowly than wild type cells and over-expression strains grown in SM medium at 37°C and 42°C. In addition, PAF-AH expression significantly increased under a series of maize root induction assay. Eicosanoic acid and ergosterol levels decreased in the PAF-AH knockouts compared to wild type cells, as revealed by GC/MS analysis. We also determined stress responses mediated by PAF-AH were related to proteins HEX1, Cu/Zn superoxide dismutase, and cytochrome c. Finally, PAF-AH exhibited antagonistic activity against Rhizoctonia solani in plate confrontation assays. Our results indicate PAF-AH may play an important role in T. harzianum stress response and antagonism under diverse environmental conditions. PMID:24964161

  16. Plant growth-promoting fungus Penicillium spp. GP15-1 enhances growth and confers protection against damping-off and anthracnose in the cucumber.

    PubMed

    Hossain, Md Motaher; Sultana, Farjana; Miyazawa, Mitsuo; Hyakumachi, Mitsuro

    2014-01-01

    Plant growth-promoting fungi (PGPF) have the potential to confer several benefits to plants in terms of growth and protection against pests and pathogens. In the present study, we tested whether a PGPF isolate, Penicillium spp. GP15-1 (derived from zoysiagrass rhizospheres), stimulates growth and disease resistance in the cucumber plant. The use of the barley grain inoculum GP15-1 significantly enhanced root and shoot growth and biomass of cucumber plants. A root colonization study revealed that GP15-1 was a very rapid and efficient root colonizer and was isolated in significantly higher frequencies from the upper root parts than from the middle and lower root parts during the first 14 d of seedling growth. Inoculating the cucumber seedlings with GP15-1 significantly reduced the damping-off disease caused by Rhizoctonia solani, and the disease suppression effects of GP15-1 were considerably influenced by the inoculum potential of both GP15-1 and the pathogen. Treatment with the barley grain inoculum or a cell-free filtrate of GP15-1 increased systemic resistance against leaf infection by the anthracnose pathogen Colletotrichum orbiculare, resulting in a significant decrease in lesion number and size. Molecular and phylogenetic analyses of internal transcribed spacer sequences of the genomic DNA of GP15-1 revealed that the fungal isolate is a strain of either Penicillium neoechinulatum or Penicillium viridicatum. PMID:24671024

  17. Partial purification, characterization, and kinetic studies of a low-molecular-weight, alkali-tolerant chitinase enzyme from Bacillus subtilis JN032305, A potential biocontrol strain.

    PubMed

    Shivakumar, Srividya; Karmali, Anika Nayak; Ruhimbana, Charles

    2014-01-01

    A new alkalophilic low-molecular-mass chitinase of 14 kD from the potent biocontrol agent Bacillus subtilis JN032305 was partially purified and enzymology of the chitinase was studied. The enzyme showed optimal pH of 9.0 and temperature of 50°C. The enzyme was found stable during the 60-min incubation at 50 °C. The chitinase was inhibited by group specific agents like IAA, DAN, TLCK, and SDS and metal ions Mg(2+), Ca(2+), Fe(2+), Mn(2+), Ba(2+), and Hg(2+), whereas Zn(2+) did not show significant inhibitory effect against the chitinase. PMSF partially inhibited the enzyme. Substrates specificity tests indicated that the enzyme showed 75% of relative activity on glycol chitin, 58% on carboxymethylcellulose (CMC), 33% on chitin flakes, and 166% laminarin compared to that on colloidal chitin. The enzyme also hydrolyzed 4-methylumbelliferyl-N-acetyl-D-glucosaminide, indicating its chitobiase activity. The chitinase of this study has broad specificity, which could hydrolyze not only the glycosidic bond in GlcNAc-GlcNAc but also that of related carbohydrates with glycosidic linkages. The partially purified chitinase not only showed antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides, two potent phytopathogens of chilli, but also increased the germination of chilli seeds when infected with the two potent phytopathogenic fungi. PMID:24499366

  18. Identification of antifungal niphimycin from Streptomyces sp. KP6107 by screening based on adenylate kinase assay.

    PubMed

    Kim, Hye Yoon; Kim, Jeong Do; Hong, Jin Sung; Ham, Jong Hyun; Kim, Beom Seok

    2013-07-01

    Microbial culture extracts are used for natural product screening to find antifungal lead compounds. A microbial culture extract library was constructed using 343 actinomycete isolates to examine the value of the adenylate kinase (AK) assay for screening to identify antifungal metabolites that disrupt cell integrity in plant pathogenic fungi. A culture extract of Streptomyces sp. strain KP6107 lysed cells of Fusarium oxysporum f.sp. lycopersici which resulted in high AK activity. The active ingredient N-1 was purified from the culture extract using various chromatographic procedures and identified to be the guanidyl-polyol macrolide antibiotic, niphimycin, which is a potent fungal cell membrane disruptor. Niphimycin showed broad-spectrum antifungal activity against Alternaria mali, Aspergillus oryzae, Colletotrichum coccodes, Colletotrichum gloeosporioides, Cercospora canescens, Cylindrocarpon destructans, F. oxysporum f.sp. cucumerinum, F. oxysporum f.sp. lycopersici, and Rhizoctonia solani at concentrations of 8-64?µg?ml(-1). Anthracnose development in pepper plants was completely inhibited by treatment with 50 µg?ml(-1) niphimycin, which was as effective as chlorothalonil. These results show that the AK assay is an efficient and selective tool in screening for cell membrane/wall disruptors of plant pathogenic fungi. PMID:22915202

  19. Characterization of the bioactive metabolites from a plant growth-promoting rhizobacteria and their exploitation as antimicrobial and plant growth-promoting agents.

    PubMed

    George, Emrin; Kumar, S Nishanth; Jacob, Jubi; Bommasani, Bhaskara; Lankalapalli, Ravi S; Morang, P; Kumar, B S Dileep

    2015-05-01

    A plant growth-promoting bacterial strain, PM 105, isolated from a tea plantation soil from the North Eastern region of India was identified as Pseudomonas aeruginosa through classical and 16S ribosomal DNA (rDNA) gene sequencing. Further studies with this strain confirmed broad spectrum antifungal activity against ten human and plant pathogenic fungal pathogens viz. Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus tubingensis, Candida albicans, Colletotrichum gloeosporioides, Fusarium oxysporum, Pencillium expansum, Rhizoctonia solani, Trichophyton rubrum besides growth-promoting property in cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan). However, no antibacterial property was exhibited by this strain against the four test bacterial pathogens tested in agar overlay method. The crude bioactive metabolites produced by this strain were isolated with three different solvents that exhibited significant antimicrobial and plant growth-promoting activity. Chloroform extract recorded significant antimicrobial and plant growth-promoting activity. Three major compounds viz. 1-hydroxyphenazine, pyocyanin, and phenazine-1-carboxamide were purified and characterized from crude extracts of this strain by various spectral data. The purified compounds recorded prominent antimicrobial activity but failed to establish the plant growth promotion activity in test crop plants under gnotobiotic conditions. Pyocyanin recorded significant antimicrobial activity, and best activity was recorded against T. rubrum (29 mm), followed by P. expansum (28 mm). These results suggest the use of PM 105 as plant growth-promoting agent in crop plants after successful field trials. PMID:25832181

  20. Prediction of invasion from the early stage of an epidemic.

    PubMed

    Pérez-Reche, Francisco J; Neri, Franco M; Taraskin, Sergei N; Gilligan, Christopher A

    2012-09-01

    Predictability of undesired events is a question of great interest in many scientific disciplines including seismology, economy and epidemiology. Here, we focus on the predictability of invasion of a broad class of epidemics caused by diseases that lead to permanent immunity of infected hosts after recovery or death. We approach the problem from the perspective of the science of complexity by proposing and testing several strategies for the estimation of important characteristics of epidemics, such as the probability of invasion. Our results suggest that parsimonious approximate methodologies may lead to the most reliable and robust predictions. The proposed methodologies are first applied to analysis of experimentally observed epidemics: invasion of the fungal plant pathogen Rhizoctonia solani in replicated host microcosms. We then consider numerical experiments of the susceptible-infected-removed model to investigate the performance of the proposed methods in further detail. The suggested framework can be used as a valuable tool for quick assessment of epidemic threat at the stage when epidemics only start developing. Moreover, our work amplifies the significance of the small-scale and finite-time microcosm realizations of epidemics revealing their predictive power. PMID:22513723

  1. Susceptibility and Resistance of Several Fungi to Microbial Lysis1

    PubMed Central

    Potgieter, H. J.; Alexander, M.

    1966-01-01

    Potgieter, H. J. (Cornell University, Ithaca, N.Y.), and M. Alexander. Susceptibility and resistance of several fungi to microbial lysis. J. Bacteriol. 91:1526–1532. 1966.—Strains of Streptomyces, Nocardia, and Pseudomonas capable of lysing hyphae of Fusarium solani or Neurospora crassa were obtained by selective culture, but attempts to isolate an organism lysing Rhizoctonia solani failed. When provided with F. solani or N. crassa as carbon sources, the actinomycetes tested produced ?-(1 ? 3) glucanase and chitinase. A mixture containing purified chitinase and ?-(1 ? 3) glucanase induced spheroplast formation in F. solani, caused some morphological changes in N. crassa, but had almost no effect on R. solani hyphae. The polysaccharides in R. solani walls, which contain a large amount of glucose as well as galactose, mannose, and glucosamine, were not hydrolyzed appreciably by the two enzymes. Laminaribiose and laminaritriose were released by enzymatic hydrolysis of F. solani and N. crassa walls, and gentiobiose was liberated from R. solani and N. crassa walls. Melaninlike materials were found in R. solani walls, accounting for 8.50% of the wall weight. A role for melanin in protecting hyphae from microbial lysis is suggested. PMID:5929777

  2. A Single-Step Purification of Cauliflower Lysozyme and Its Dual Role Against Bacterial and Fungal Plant Pathogens.

    PubMed

    Manikandan, Muthu; Balasubramaniam, R; Chun, Se-Chul

    2015-09-01

    A novel lysozyme from cauliflower was purified in a single step, for the first time, using Sephadex G100 column chromatography. The purified lysozyme exhibited a homogenized single band in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and its molecular mass was calculated to be 22.0 kDa. The purified lysozyme showed activity between 30 to 60 °C with 40 °C as the optimum temperature for its maximal activity. Although the purified lysozyme was functional at pH ranges between 3.0 and 9.0, the optimum pH for the enzyme activity was 8.0. By Michaelis-Menten equation, the threshold substrate concentration for the optimal enzyme activity was calculated to be 133.0 ?g. The purified lysozyme showed extraordinary activity against plant pathogenic bacteria and fungi. At 10-?g concentrations, it inhibited the growth of plant pathogenic bacteria such as Pseudomonas syringae, Xanthomonas campestris, and Erwinia carotovora exhibiting 4.28, 5.90, and 3.88-fold inhibition, respectively. Further, it also completely inhibited the conidial germination of Archemonium obclavatum and, to a very large extent, other fungal species such as Fusarium solani (79.3 %), Leptosphaeria maculans (88.6 %), Botrytis cinera (73.3 %), Curvularia lunata (68 %), Rhizoctonia solani (79.6 %), and Alternaria alternata (83.6 %). PMID:26208688

  3. Heterologous expression of the antifungal ?-chitin binding protein CBP24 from bacillus thuringiensis and its synergistic action with bacterial chitinases.

    PubMed

    Mehmood, Muhammad A; Latif, Mamoona; Hussain, Khadim; Gull, Munazza; Latif, Farooq; Rajoka, Muhammad I

    2015-01-01

    The genome sequence analysis of Bacillus thuringiensis serovar konkukian S4 has shown to contain two chitinases (Chi74, Chi39) and two chitin-binding proteins (CBP50 and CBP24). The Chi74, Chi39 and CBP50 have been characterized previously. The chitin-binding protein CBP24 was cloned and heterologously expressed in Escherichia coli. The recombinant protein was purified using a Ni-NTA purification system. The purified protein was used to study its substrate binding activity using crystalline chitin variants as substrates. The Bmax and Kd values have shown that it preferably binds to ?-type of the crystalline chitin at a range of pH with peak activity between 5.5-7.5. To elucidate the role of CBP24 in the chitin degradation system of S4, the purified chitinases Chi74, Chi39 along with the ChiA from Serratia proteamcualans were used in different combinations with the CBP24 and chitinolytic activity was assayed. It was shown that the CBP24 acts synergistically with chitin degradation activity of bacterial chitinases non-specifically. Moreover, the CBP24 has shown antifungal activity against plant pathogenic fungi Fusarium oxysporum and Rhizoctonia solani. The present study will lead us to develop a technology for environmental friendly conversion of chitin to valuable products. PMID:25182053

  4. Signaling via the Trichoderma atroviride mitogen-activated protein kinase Tmk1 differentially affects mycoparasitism and plant protection

    PubMed Central

    Reithner, Barbara; Schuhmacher, Rainer; Stoppacher, Norbert; Pucher, Marion; Brunner, Kurt; Zeilinger, Susanne

    2015-01-01

    Trichoderma atroviride is a mycoparasite of a number of plant pathogenic fungi thereby employing morphological changes and secretion of cell wall degrading enzymes and antibiotics. The function of the tmk1 gene encoding a mitogen-activated protein kinase (MAPK) during fungal growth, mycoparasitic interaction, and biocontrol was examined in T. atroviride. ?tmk1 mutants exhibited altered radial growth and conidiation, and displayed de-regulated infection structure formation in the absence of a host-derived signal. In confrontation assays, tmk1 deletion caused reduced mycoparasitic activity although attachment to Rhizoctonia solani and Botrytis cinerea hyphae was comparable to the parental strain. Under chitinase-inducing conditions, nag1 and ech42 transcript levels and extracellular chitinase activities were elevated in a ?tmk1 mutant, whereas upon direct confrontation with R. solani or B. cinerea a host-specific regulation of ech42 transcription was found and nag1 gene transcription was no more inducible over an elevated basal level. ?tmk1 mutants exhibited higher antifungal activity caused by low molecular weight substances, which was reflected by an over-production of 6-pentyl-?-pyrone and peptaibol antibiotics. In biocontrol assays, a ?tmk1 mutant displayed a higher ability to protect bean plants against R. solani. PMID:17509915

  5. Homotypic clustering of OsMYB4 binding site motifs in promoters of the rice genome and cellular-level implications on sheath blight disease resistance.

    PubMed

    Pooja, Singh; Sweta, Kumari; Mohanapriya, A; Sudandiradoss, C; Siva, Ramamoorthy; Gothandam, Kodiveri M; Babu, Subramanian

    2015-05-01

    The promoter regions (1 kb upstream sequences) of 45,836 annotated genes of rice were analyzed for the presence of OsMYB4 binding sites using a Perl program algorithm. Based on the homotypic clustering concept, 113 promoters were found to have more than 4 binding site motifs. Among the downstream genes of these promoters, five genes which are known to have a role in disease resistance were selected and the binding capacity of OsMYB4 protein in the promoter regions was analyzed by docking studies. Expression level of these genes was analyzed by RT-PCR in Rhizoctonia solani infected rice seedlings. Upon pathogen challenge, higher expression of aminotransferase, ankyrin and WRKY 12 genes was observed corresponding to higher expression of Osmyb4. Over-expression of Osmyb4 cDNA in rice leaf tissues by agro-infection failed to result in similar over-expression of aminotransferase, ankyrin and WRKY 12 as expected. Although the role of OsMYB4 in sheath blight resistance was found to be definitive based on our initial results, artificial over-expression of this TF was observed to be insufficient in regulating the disease resistance related genes. PMID:25688880

  6. Development of pyramidal lines with two major QTLs conferring resistance to sheath blight in rice (Oryza sativa L.)

    NASA Astrophysics Data System (ADS)

    Hossain, Md Kamal; Jena, Kshirod; Bhuiyan, Md Atiqur Rahman; Ratnam, Wickneswari

    2014-09-01

    Sheath blight is an emerging threat in rice cultivation. It is animportant disease caused by the soil-borne necrotrophic pathogenic fungus, Rhizoctonia solani Kühn. However, to date neither known major genes for quantitative resistance, nor any rice lines immune to this disease has been identified. The disease resistance is quantitative in nature. Numerous genes are involved in this resistance process. There are few quantitative trait loci (QTLs) detected conferring improved resistance against the disease. Teqing and Tetepshowimproved resistance having QTLs, qSB-9 and qSBR11-1, respectively. Since, these QTLs demonstrates additive effects, pyramiding of these QTLs might be an option to increase the sheath blight resistance in rice. Nine rice cultivars were screened at greenhouse conditions. Results showed that Tetep and Teqing had the lowest disease ratings. UKMRC2a new high yielding cultivar was as recipient parent. Crosses between UKMRC2 and Teqing, and UKMRC2 and Tetep were made and confirmed. Subsequently 4-way crosses between the two F1s were performed to develop pyramidal lines.

  7. DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes

    NASA Astrophysics Data System (ADS)

    Raman, N.; Sobha, S.; Selvaganapathy, M.; Mahalakshmi, R.

    2012-10-01

    Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2rad -) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.

  8. Microemulsion formulation of Carbendazim and its in vitro antifungal activities evaluation.

    PubMed

    Leng, Pengfei; Zhang, Zhiming; Li, Qian; Zhao, Maojun; Pan, Guangtang

    2014-01-01

    The fungus Rhizoctonia solani Kuhn is a widespread and destructive plant pathogen with a very broad host range. Although various pathogens, including R. solani, have been traditionally controlled using chemical pesticides, their use faces drawbacks such as environmental pollution, development of pesticide resistance, and other negative effects. Carbendazim is a well-known antifungal agent capable of controlling a broad range of plant diseases, but its use is hampered by its poor aqueous solubility. In this study, we describe an environmentally friendly pharmaceutical microemulsion system using carbendazim as the active ingredient, chloroform and acetic acid as solvents, and the surfactants HSH and 0204 as emulsifiers. This system increased the solubility of carbendazim to 30 g/L. The optimal microemulsion formulation was determined based on a pseudo-ternary phase diagram; its physicochemical characteristics were also tested. The cloud point was greater than 90°C and it was resistant to freezing down to -18°C, both of which are improvements over the temperature range in which pure carbendazim can be used. This microemulsion meets the standard for pesticide microemulsions and demonstrated better activity against R. solani AG1-IA, relative to an aqueous solution of pure carbendazim (0.2 g/L). The mechanism of activity was reflected in the inhibition of against R. solani AG1-IA including mycelium growth, and sclerotia formation and germination were significantly better than that of 0.2 g/L carbendazim water solution according to the results of t-test done by SPSS 19. PMID:25310219

  9. In Vitro Antifungal Activity of Burkholderia gladioli pv. agaricicola against Some Phytopathogenic Fungi

    PubMed Central

    Elshafie, Hazem S.; Camele, Ippolito; Racioppi, Rocco; Scrano, Laura; Iacobellis, Nicola S.; Bufo, Sabino A.

    2012-01-01

    The trend to search novel microbial natural biocides has recently been increasing in order to avoid the environmental pollution from use of synthetic pesticides. Among these novel natural biocides are the bioactive secondary metabolites of Burkholderia gladioli pv. agaricicola (Bga). The aim of this study is to determine antifungal activity of Bga strains against some phytopathogenic fungi. The fungicidal tests were carried out using cultures and cell-free culture filtrates against Botrytis cinerea, Aspergillus flavus, Aspergillus niger, Penicillium digitatum, Penicillium expansum, Sclerotinia sclerotiorum and Phytophthora cactorum. Results demonstrated that all tested strains exert antifungal activity against all studied fungi by producing diffusible metabolites which are correlated with their ability to produce extracellular hydrolytic enzymes. All strains significantly reduced the growth of studied fungi and the bacterial cells were more bioactive than bacterial filtrates. All tested Bulkholderia strains produced volatile organic compounds (VOCs), which inhibited the fungal growth and reduced the growth rate of Fusarium oxysporum and Rhizoctonia solani. GC/MS analysis of VOCs emitted by strain Bga 11096 indicated the presence of a compound that was identified as 1-methyl-4-(1-methylethenyl)-cyclohexene, a liquid hydrocarbon classified as cyclic terpene. This compound could be responsible for the antifungal activity, which is also in agreement with the work of other authors. PMID:23208371

  10. Antifungal Activity of Paenibacillus kribbensis Strain T-9 Isolated from Soils against Several Plant Pathogenic Fungi

    PubMed Central

    Xu, Sheng Jun; Hong, Sae Jin; Choi, Woobong; Kim, Byung Sup

    2014-01-01

    The bacterial strain T-9, which shows strong antifungal activity, is isolated from the soils of Samcheok, Gangwondo and identified as Paenibacillus kribbensis according to morphological and taxonomic characteristics and 16S rRNA gene sequence analysis. The P. kribbensis strain T-9 strongly inhibits the growth of various phytopathogenic fungi including Botrytis cinerea, Colletotricum acutatum, Fusarium oxysporum f. sp. radicis-lycopersici, Magnaporthe oryzae, Phytophthora capsici, Rhizoctonia solani, and Sclerotium cepivorum in vitro. Also, the P. kribbensis strain T-9 exhibited similar or better control effects to plant diseases than in fungicide treatment through in vivo assays. In the 2-year greenhouse experiments, P. kribbensis strain T-9 was highly effective against clubroot. In the 2-year field trials, the P. kribbensis strain T-9 was less effective than the fungicide, but reduced clubroot on Chinese cabbage when compared to the control. The above-described results indicate that the strain T-9 may have the potential as an antagonist to control various phytopathogenic fungi. PMID:25288992

  11. Production of lipopeptides by Bacillus amyloliquefaciens XZ-173 in solid state fermentation using soybean flour and rice straw as the substrate.

    PubMed

    Zhu, Zhen; Zhang, Guoyi; Luo, Yi; Ran, Wei; Shen, Qirong

    2012-05-01

    This work was aimed to produce lipopeptides by Bacillus amyloliquefaciens XZ-173 in solid state fermentation using agro-industrial byproducts. A central composite design was used to get the highest lipopeptides production. Results revealed that the optimal conditions for maximum lipopeptides production were 1.79% starch and 1.91% yeast extract by employing 5.58 g soybean flour and 3.67 g rice straw as the solid substrate with initial pH 7.5, moisture content 55% and a 10% inoculum level at 30°C for 2 days. Under these conditions, the experimental yield of lipopeptides reached 50.01 mg/gds, which was very close to the predicted value (49.91 mg/gds). At high concentration, the lipopeptides extracted from fermented substrates showed strong antibiotic activity against Rhizoctonia solani and Ralstonia solanacearum and certain emulsification but good emulsion stability. This is the first report on lipopeptides production that uses rice straw as a major substrate. PMID:22418084

  12. Antiproliferative, Antibacterial and Antifungal Activity of the Lichen Xanthoria parietina and Its Secondary Metabolite Parietin

    PubMed Central

    Basile, Adriana; Rigano, Daniela; Loppi, Stefano; Di Santi, Annalisa; Nebbioso, Angela; Sorbo, Sergio; Conte, Barbara; Paoli, Luca; De Ruberto, Francesca; Molinari, Anna Maria; Altucci, Lucia; Bontempo, Paola

    2015-01-01

    Lichens are valuable natural resources used for centuries throughout the world as medicine, food, fodder, perfume, spices and dyes, as well as for other miscellaneous purposes. This study investigates the antiproliferative, antibacterial and antifungal activity of the acetone extract of the lichen Xanthoria parietina (Linnaeus) Theodor Fries and its major secondary metabolite, parietin. The extract and parietin were tested for antimicrobial activity against nine American Type Culture Collection standard and clinically isolated bacterial strains, and three fungal strains. Both showed strong antibacterial activity against all bacterial strains and matched clinical isolates, particularly against Staphylococcus aureus from standard and clinical sources. Among the fungi tested, Rhizoctonia solani was the most sensitive. The antiproliferative effects of the extract and parietin were also investigated in human breast cancer cells. The extract inhibited proliferation and induced apoptosis, both effects being accompanied by modulation of expression of cell cycle regulating genes such as p16, p27, cyclin D1 and cyclin A. It also mediated apoptosis by activating extrinsic and intrinsic cell death pathways, modulating Tumor Necrosis Factor-related apoptosis-inducing ligand (TRAIL) and B-cell lymphoma 2 (Bcl-2), and inducing Bcl-2-associated agonist of cell death (BAD) phosphorylation. Our results indicate that Xanthoria parietina is a major potential source of antimicrobial and anticancer substances. PMID:25860944

  13. Antiproliferative, antibacterial and antifungal activity of the lichen Xanthoria parietina and its secondary metabolite parietin.

    PubMed

    Basile, Adriana; Rigano, Daniela; Loppi, Stefano; Di Santi, Annalisa; Nebbioso, Angela; Sorbo, Sergio; Conte, Barbara; Paoli, Luca; De Ruberto, Francesca; Molinari, Anna Maria; Altucci, Lucia; Bontempo, Paola

    2015-01-01

    Lichens are valuable natural resources used for centuries throughout the world as medicine, food, fodder, perfume, spices and dyes, as well as for other miscellaneous purposes. This study investigates the antiproliferative, antibacterial and antifungal activity of the acetone extract of the lichen Xanthoria parietina (Linnaeus) Theodor Fries and its major secondary metabolite, parietin. The extract and parietin were tested for antimicrobial activity against nine American Type Culture Collection standard and clinically isolated bacterial strains, and three fungal strains. Both showed strong antibacterial activity against all bacterial strains and matched clinical isolates, particularly against Staphylococcus aureus from standard and clinical sources. Among the fungi tested, Rhizoctonia solani was the most sensitive. The antiproliferative effects of the extract and parietin were also investigated in human breast cancer cells. The extract inhibited proliferation and induced apoptosis, both effects being accompanied by modulation of expression of cell cycle regulating genes such as p16, p27, cyclin D1 and cyclin A. It also mediated apoptosis by activating extrinsic and intrinsic cell death pathways, modulating Tumor Necrosis Factor-related apoptosis-inducing ligand (TRAIL) and B-cell lymphoma 2 (Bcl-2), and inducing Bcl-2-associated agonist of cell death (BAD) phosphorylation. Our results indicate that Xanthoria parietina is a major potential source of antimicrobial and anticancer substances. PMID:25860944

  14. Relevance of trichothecenes in fungal physiology: disruption of tri5 in Trichoderma arundinaceum.

    PubMed

    Malmierca, Mónica G; Cardoza, Rosa Elena; Alexander, Nancy J; McCormick, Susan P; Collado, Isidro G; Hermosa, Rosa; Monte, Enrique; Gutiérrez, Santiago

    2013-04-01

    Trichothecenes are sesquiterpenoid mycotoxins produced mainly by Fusarium species. Harzianum A (HA), a non-phytotoxic trichothecene produced by Trichoderma arundinaceum, has recently been found to have antagonistic activity against fungal plant pathogens and to induce plant genes involved in defense responses. In the present work, we have shown that disruption of the T. arundinaceum tri5 gene, which encodes a terpene synthase, stops the production of HA, alters the expression of other tri genes involved in HA biosynthesis, and alters the expression of hmgR, dpp1, erg9, erg1, and erg7, all genes involved in terpene biosynthetic pathways. An increase in the level of ergosterol biosynthesis was also observed in the tri5 disrupted transformant in comparison with the wild type strain. The loss of HA also resulted in a drastic reduction of the biocontrol activity of the transformants against the phytopathogenic fungi Botrytis cinerea and Rhizoctonia solani. Finally, the effect of tri5 gene disruption on the regulation and balance of intermediates in terpene biosynthetic pathways, as well as the hypothetical physiological role of trichothecenes, both inter- and intracellularly, on regulation and biocontrol, are discussed. PMID:23454546

  15. A new antifungal protein and a chitinase with prominent macrophage-stimulating activity from seeds of Phaseolus vulgaris cv. pinto.

    PubMed

    Ye, X Y; Ng, T B

    2002-01-18

    From the seeds of the pinto bean (Phaseolus vulgaris cv. pinto), a chitinase and a novel antifungal protein, both with the ability of markedly augmenting nitrite production by murine peritoneal macrophages, were isolated. The antifungal proteins, designated phasein A and phasein B, exhibited molecular weights of 28 and 32 kDa, respectively. Phaseins A and B were adsorbed on Affi-gel blue gel and CM-Sepharose and were eluted as adjacent peaks from CM-Sepharose. Phasein A demonstrated potent antifungal activity toward Fusarium oxysporum and Physalospora piricola. Phasein B was more potent than phasein A toward P. piricola but less potent than phasein A toward F. oxysporum and Rhizoctonia solani. Both antifungal proteins inhibited the activity of HIV-1 reverse transcriptase and translation in a rabbit reticulocyte lysate system, with phasein B being more potent. Nitrite production by mouse macrophages was greatly boosted in the presence of both phaseins A and B, although the effect of phasein A was more prominent. The bioactivities of phaseins were in general potent compared with those of other antifungal proteins. PMID:11785974

  16. Chemical constituents and antimicrobial properties of the essential oil and ethanol extract from the stem of Aglaia odorata Lour.

    PubMed

    Joycharat, Nantiya; Thammavong, Sonesay; Voravuthikunchai, Supayang Piyawan; Plodpai, Patimaporn; Mitsuwan, Watcharapong; Limsuwan, Surasak; Subhadhirasakul, Sanan

    2014-01-01

    The stem-derived essential oil of Aglaia odorata Lour. was obtained by hydrodistillation using a Clevenger-type system. Gas chromatography-mass spectrometry analysis of the oil revealed the identification of 39 compounds, representing 76.4% of the oil; germacrene D (20.3%), ?-humulene (17.1%), ?-himachalene (12.7%) and ?-caryophyllene (10.2%) were the major components. Ar-turmerone (1) and eichlerialactone (2) were isolated from the stem oil and ethanolic stem extract of this plant species, respectively. Antimicrobial activities of the oil and ethanol extract were tested against both Gram-positive and Gram-negative bacterial strains including Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, Acinetobacter baumannii ATCC 19606 and Escherichia coli ATCC 25922, as well as three rice fungal pathogens Bipolaris oryzae, Pyricularia oryzae and Rhizoctonia solani using broth microdilution method. The oil and 1 exhibited significant antifungal activity against the three rice pathogens tested, whereas 2 exhibited good antibacterial activity against both the Gram-positive pathogens tested. PMID:24934340

  17. Synthesis and Fungicidal Activities of (Z/E)-3,7-Dimethyl-2,6-octadienamide and Its 6,7-Epoxy Analogues.

    PubMed

    Yang, Mingyan; Dong, Hongbo; Jiang, Jiazhen; Wang, Mingan

    2015-01-01

    In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl-2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and ¹H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 µg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC50 values of 4.3 and 9.7 µM against Fusahum graminearum and R. Solani, respectively. PMID:26610465

  18. DNA interaction, antimicrobial, electrochemical and spectroscopic studies of metal(II) complexes with tridentate heterocyclic Schiff base derived from 2?-methylacetoacetanilide

    NASA Astrophysics Data System (ADS)

    Raman, Natarajan; Pothiraj, Krishnan; Baskaran, Thanasekaran

    2011-08-01

    A new Schiff base ligand (HL) was synthesized by the condensation reaction between 2'-methyleacetoacetanilide and 2-amino-3-hydroxypyridine. Its Co(II), Ni(II), Cu(II) and Zn(II) complexes were prepared by the interaction of the ligand with metal(II) chloride. They were characterized by elemental analysis, IR, 1H NMR, EPR, UV-Vis, magnetic susceptibility measurements, conductivity measurements and FAB-mass spectra. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption, viscosity and cyclic voltammetry methods, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. It was found to be oxidative hydroxyl radical cleavage in the presence of 3-mercaptopropionic acid (MPA). The Schiff base and its complexes have been screened for their antibacterial ( Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa) and antifungal ( Aspergillus niger, Rhizopus stolonifer, Rhizoctonia bataicola and Candida albicans) activities and the data reveal that the complexes have higher activity than the free ligand.

  19. Study of the antifungal activity of Acinetobacter baumannii LCH001 in vitro and identification of its antifungal components.

    PubMed

    Liu, C H; Chen, X; Liu, T T; Lian, B; Gu, Yucheng; Caer, V; Xue, Y R; Wang, B T

    2007-08-01

    An Acinetobacter strain, given the code name LCH001 and having the potential to be an endophytic antagonist, has been isolated from healthy stems of the plant Cinnamomum camphora (L.) Presl, guided by an in vitro screening technique. The bacterium inhibited the growth of several phytopathogenic fungi such as Cryphonectria parasitica, Glomerella glycines, Phytophthora capsici, Fusarium graminearum, Botrytis cinerea, and Rhizoctonia solani. Biochemical, physiological, and 16S rDNA sequence analysis proved that it is Acinetobacter baumannii. When the filtrate from the fermentation broth of strain LCH001 was tested in vitro and in vivo, it showed strong growth inhibition against several phytopathogens including P. capsici, F. graminearum, and R. solani, indicating that suppression of the growth of the fungi was due to the presence of antifungal compounds in the culture broth. Moreover, the antifungal activity of the culture filtrate was significantly correlated with the cell growth of strain LCH001. The active metabolites in the filtrate were relatively thermally stable, but were sensitive to acidic conditions. Three antifungal compounds were isolated from the culture broth by absorption onto macropore resin, ethanol extraction, chromatography on silica gel or LH-20 columns, and crystallization. The structures of the bioactive compounds were identified by spectroscopic methods as isomers of iturin A, namely, iturin A2, iturin A3, and iturin A6. The characterization of an unusual endophytic bacterial strain LCH001 and its bioactive components may provide an alternative resource for the biocontrol of plant diseases. PMID:17534613

  20. Non-cytotoxic antifungal agents: isolation and structures of gageopeptides A-D from a Bacillus strain 109GGC020.

    PubMed

    Tareq, Fakir Shahidullah; Lee, Min Ah; Lee, Hyi-Seung; Lee, Yeon-Ju; Lee, Jong Seok; Hasan, Choudhury M; Islam, Md Tofazzal; Shin, Hee Jae

    2014-06-18

    Antifungal resistance and toxicity problems of conventional fungicides highlighted the requirement of search for new safe antifungal agents. To comply with the requirement, we discovered four new non-cytotoxic lipopeptides, gageopeptides A-D, 1-4, from a marine-derived bacterium Bacillus subtilis. The structures and stereochemistry of gageopeptides were determined by NMR data analysis and chemical means. Gageopeptides exhibited significant antifungal activities against pathogenic fungi Rhizoctonia solani, Botrytis cinerea, and Colletotrichum acutatum with minimum inhibitory concentration (MIC) values of 0.02-0.06 ?M. In addition, these lipopeptides showed significant motility inhibition and lytic activities against zoospores of the late blight pathogen Phytophthora capsici. These compounds also showed potent antimicrobial activity against Gram positive and Gram negative bacteria with MIC values of 0.04-0.08 ?M. However, gageopeptides A-D did not exhibit any cytotoxicity (GI50 > 25 ?M) against cancer cell lines in sulforhodamine B (SRB), 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), and WST-1 ((4-[3-4-iodophenyl]-2-(4-nitrophenyl)-2H-5-tetrazolio)-1,3-benzene disulfonate)) assays, demonstrating that these compounds could be promising candidates for the development of non-cytotoxic antifungal agents. PMID:24857413

  1. The effects of some polyamine biosynthetic inhibitors on growth and morphology of phytopathogenic fungi

    NASA Technical Reports Server (NTRS)

    Rajam, M. V.; Galston, A. W.

    1985-01-01

    We have studied the effects of two polyamine biosynthetic inhibitors, alpha-difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA), and of polyamines (PAs), alone and in combination, on mycelial growth and morphology of four phytopathogenic fungi: Botrytis sp, B. cinerea, Rhizoctonia solani and Monilinia fructicola. The inhibitors were added to a Czapek agar medium to get final concentrations of 0.1, 0.5 and 1.0 mM. DFMO and DFMA, suicide inhibitors of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) respectively, inhibited mycelial growth strongly; the effect was generally more pronounced with DFMA than with DFMO, but each fungus had its own response pattern. The addition of the PAs putrescine (Put) and spermidine (Spd) to the culture medium resulted in a promotion of growth. In Botrytis sp and Monilinia fructicola exposed to inhibitors plus PAs, mycelial growth was actually increased above control values. Mycelial morphology was altered and cell size dramatically reduced in plates containing inhibitors alone, whereas with PAs alone, or in combination with inhibitors, morphology was normal, but cell length and diameters increased considerably. These results suggest that PAs are essential for growth in fungal mycelia. The inhibition caused by DFMA may be due to its arginase-mediated conversion to DFMO.

  2. Plant growth promoting bacteria from cow dung based biodynamic preparations.

    PubMed

    Radha, T K; Rao, D L N

    2014-12-01

    Indigenous formulations based on cow dung fermentation are commonly used in organic farming. Three biodynamic preparations viz., Panchagavya (PG), BD500 and 'Cow pat pit' (CPP) showed high counts of lactobacilli (10(9) ml(-1)) and yeasts (10(4) ml(-1)). Actinomycetes were present only in CPP (10(4) ml(-1)) and absent in the other two. Seven bacterial isolates from these ferments were identified by a polyphasic approach: Bacillus safensis (PG1), Bacillus cereus (PG2, PG4 PG5), Bacillus subtilis (BD2) Lysinibacillus xylanilyticus (BD3) and Bacillus licheniformis (CPP1). This is the first report of L. xylanilyticus and B. licheniformis in biodynamic preparations. Only three carbon sources-dextrose, sucrose and trehalose out of 21 tested were utilized by all the bacteria. None could utilize arabinose, dulcitol, galactose, inositol, inulin, melibiose, raffinose, rhamnose and sorbitol. All the strains produced indole acetic acid (1.8-3.7 ?g ml(-1) culture filtrate) and ammonia. None could fix nitrogen; but all except B. safensis and B. licheniformis could solubilize phosphorous from insoluble tri-calcium phosphate. All the strains except L. xylaniliticus exhibited antagonism to the plant pathogen Rhizoctonia bataticola whereas none could inhibit Sclerotium rolfsi. In green house experiment in soil microcosms, bacterial inoculation significantly promoted growth of maize; plant dry weight increased by ~21 % due to inoculation with B. cereus (PG2). Results provide a basis for understanding the beneficial effects of biodynamic preparations and industrial deployment of the strains. PMID:25320439

  3. Selection of available suicide vectors for gene mutagenesis using chiA (a chitinase encoding gene) as a new reporter and primary functional analysis of chiA in Lysobacter enzymogenes strain OH11.

    PubMed

    Qian, Guoliang; Wang, Yansheng; Qian, Dongyu; Fan, Jiaqin; Hu, Baishi; Liu, Fengquan

    2012-02-01

    Here, three different suicide vectors were evaluated for the possibility of performing gene mutagenesis in strain OH11 using the chiA gene (accession number: DQ888611) as a new reporter. Suicide vector pEX18GM was selected, and it was successfully applied for disruption and in-frame deletions in the chiA gene in strain OH11, which was confirmed by PCR amplification and Southern hybridization. The chiA-deletion mutant OH11-3 did not have the ability to produce chitinase on chitine selection medium. Interestingly, the chiA-deletion mutants displayed wild-type antimicrobial activity against Saccharomyces cerevisiae, Magnaporthe grisea, Phytophthora capsici, Rhizoctonia solani, Sclerotinia sclerotiorum and Pythium ultimum. Our data suggest that chitinase might not be a unique lytic enzyme in controlling S. cerevisiae, M. grisea, P. capsici, and P. ultimum. R. solani, S. sclerotiorum. Also, suicide vector pEX18GM might be explored as a potential tool for gene deletions in L. enzymogenes, which will facilitate the molecular study of mechanisms of biological control in L. enzymogenes. PMID:22806850

  4. Indigenous populations of three closely related Lysobacter spp. in agricultural soils using real-time PCR.

    PubMed

    Postma, Joeke; Schilder, Mirjam T; van Hoof, Richard A

    2011-11-01

    Previous research had shown that three closely related species of Lysobacter, i.e., Lysobacter antibioticus, Lysobacter capsici, and Lysobacter gummosus, were present in different Rhizoctonia-suppressive soils. However, the population dynamics of these three Lysobacter spp. in different habitats remains unknown. Therefore, a specific primer-probe combination was designed for the combined quantification of these three Lysobacter spp. using TaqMan. Strains of the three target species were efficiently detected with TaqMan, whereas related non-target strains of Lysobacter enzymogenes and Xanthomonas campestris were not or only weakly amplified. Indigenous Lysobacter populations were analyzed in soils of 10 organic farms in the Netherlands during three subsequent years with TaqMan. These soils differed in soil characteristics and crop rotation. Additionally, Lysobacter populations in rhizosphere and bulk soil of different crops on one of these farms were studied. In acid sandy soils low Lysobacter populations were present, whereas pH neutral clay soils contained high populations (respectively, <4.0-5.87 and 6.22-6.95 log gene copy numbers g(-1) soil). Clay content, pH and C/N ratio, but not organic matter content in soil, correlated with higher Lysobacter populations. Unexpectedly, different crops did not significantly influence population size of the three Lysobacter spp. and their populations were barely higher in rhizosphere than in bulk soil. PMID:21448673

  5. Pectin localization in the Mediterranean orchid Limodorum abortivum reveals modulation of the plant interface in response to different mycorrhizal fungi.

    PubMed

    Paduano, Chiara; Rodda, Michele; Ercole, Enrico; Girlanda, Mariangela; Perotto, Silvia

    2011-02-01

    In most mycorrhizal symbioses, phylogenetically distinct fungi colonize simultaneously the roots of individual host plants. A matter of debate is whether plants can distinguish among these fungal partners and differentiate their cellular responses. We have addressed this question in the orchid mycorrhizal symbiosis, where individual roots of the Mediterranean species Limodorum abortivum can be colonized by a dominant unculturable fungal symbiont belonging to the genus Russula and by more sporadic mycelia in the genus Ceratobasidium (form-genus Rhizoctonia). The phylogenetic position of the Ceratobasidium symbionts was further investigated in this work. Both Russula and Ceratobasidium symbionts form intracellular coils in the cortical roots of L. abortivum, but hyphae are very different in size and morphology, making the two fungi easily distinguishable. We have used John Innes Monoclonal 5, a widely used monoclonal antibody against pectin, to investigate the composition of the symbiotic plant interface around the intracellular coils formed by the two fungal partners. Immunolabelling experiments showed that pectin is exclusively found in the interface formed around the Ceratobasidium, and not around the Russula symbiont. These data indicate that the plant responses towards distinct mycorrhizal fungal partners can vary at a cellular level. PMID:20428900

  6. Diversity of mycorrhizal fungi of terrestrial orchids: compatibility webs, brief encounters, lasting relationships and alien invasions.

    PubMed

    Bonnardeaux, Yumiko; Brundrett, Mark; Batty, Andrew; Dixon, Kingsley; Koch, John; Sivasithamparam, K

    2007-01-01

    The diversity of mycorrhizal fungi associated with an introduced weed-like South African orchid (Disa bracteata) and a disturbance-intolerant, widespread, native West Australian orchid (Pyrorchis nigricans) were compared by molecular identification of the fungi isolated from single pelotons. Molecular identification revealed both orchids were associated with fungi from diverse groups in the Rhizoctonia complex with worldwide distribution. Symbiotic germination assays confirmed the majority of fungi isolated from pelotons were mycorrhizal and a factorial experiment uncovered complex webs of compatibility between six terrestrial orchids and 12 fungi from Australia and South Africa. Two weed-like (disturbance-tolerant rapidly spreading) orchids - D. bracteata and the indigenous Australian Microtis media, had the broadest webs of mycorrhizal fungi. In contrast, other native orchids had relatively small webs of fungi (Diuris magnifica and Thelymitra crinita), or germinated exclusively with their own fungus (Caladenia falcata and Pterostylis sanguinea). Orchids, such as D. bracteata and M. media, which form relationships with diverse webs of fungi, had apparent specificity that decreased with time, as some fungi had brief encounters with orchids that supported protocorm formation but not subsequent seedling growth. The interactions between orchid mycorrhizal fungi and their hosts are discussed. PMID:17289365

  7. Isolation and identification of endophytic and mycorrhizal fungi from seeds and roots of Dendrobium (Orchidaceae).

    PubMed

    Chen, Juan; Wang, Hui; Guo, Shun-Xing

    2012-05-01

    The seed germination of orchids under natural conditions requires association with mycorrhizal fungi. Dendrobium nobile and Dendrobium chrysanthum are threatened orchid species in China where they are considered medicinal plants. For conservation and application of Dendrobium using symbiosis technology, we isolated culturable endophytic and mycorrhizal fungi colonized in the protocorms and adult roots of two species plants and identified them by morphological and molecular analyses (5.8S and nrLSU). Of the 127 endophytic fungi isolated, 11 Rhizoctonia-like strains were identified as Tulasnellales (three strains from protocorms of D. nobile), Sebacinales (three strains from roots of D. nobile and two strains from protocorms of D. chrysanthum) and Cantharellales (three strains from roots of D. nobile), respectively. In addition, species of Xylaria, Fusarium, Trichoderma, Colletotrichum, Pestalotiopsis, and Phomopsis were the predominant non-mycorrhizal fungi isolated, and their probable ecological roles in the Dendrobium plants are discussed. These fungal resources will be of great importance for the large-scale cultivation of Dendrobium plants using symbiotic germination technology and for the screening of bioactive metabolites from them in the future. PMID:21779810

  8. Identification of QTLs and possible candidate genes conferring sheath blight resistance in rice (Oryza sativa L.).

    PubMed

    Yadav, Shailesh; Anuradha, Ghanta; Kumar, Ravi Ranjan; Vemireddy, Lakshminaryana Reddy; Sudhakar, Ravuru; Donempudi, Krishnaveni; Venkata, Durgarani; Jabeen, Farzana; Narasimhan, Yamini Kalinati; Marathi, Balram; Siddiq, Ebrahimali Abubacker

    2015-01-01

    Sheath blight, caused by the pathogenic fungus Rhizoctonia solani Kühn, is one of the most devastating diseases in rice. Breeders have always faced challenges in acquiring reliable and absolute resistance to this disease in existing rice germplasm. In this context, 40 rice germplasm including eight wild, four landraces, twenty- six cultivated and two advanced breeding lines were screened utilizing the colonized bits of typha. Except Tetep and ARC10531 which expressed moderate level of resistance to the disease, none could be found to be authentically resistant. In order to map the quantitative trait loci (QTLs) governing the sheath blight resistance, two mapping populations (F2 and BC1F2) were developed from the cross BPT-5204/ARC10531. Utilizing composite interval mapping analysis, 9 QTLs mapped to five different chromosomes were identified with phenotypic variance ranging from 8.40 to 21.76%. Two SSR markers namely RM336 and RM205 were found to be closely associated with the major QTLs qshb7.3 and qshb9.2 respectively and were attested as well in BC1F2 population by bulk segregant analysis approach. A hypothetical ? 1-3 glucanase with other 31 candidate genes were identified in silico utilizing rice database RAP-DB within the identified QTL region qshb9.2. A detailed insight into these candidate genes will facilitate at molecular level the intricate nature of sheath blight, a step forward towards functional genomics. PMID:25977888

  9. Wheat puroindolines enhance fungal disease resistance in transgenic rice.

    PubMed

    Krishnamurthy, K; Balconi, C; Sherwood, J E; Giroux, M J

    2001-10-01

    Antimicrobial peptides play a role in the immune systems of animals and plants by limiting pathogen infection and growth. The puroindolines, endosperm-specific proteins involved in wheat seed hardness, are small proteins reported to have in vitro antimicrobial properties. Rice, the most widely used cereal crop worldwide, normally does not contain puroindolines. Transgenic rice plants that constitutively express the puroindoline genes pinA and/or pinB throughout the plants were produced. PIN extracts of leaves from the transgenic plants reduced in vitro growth of Magnaporthe grisea and Rhizoctonia solani, two major fungal pathogens of rice, by 35 to 50%. Transgenic rice expressing pinA and/or pinB showed significantly increased tolerance to M. grisea (rice blast), with a 29 to 54% reduction in symptoms, and R. solani (sheath blight), with an 11 to 22% reduction in symptoms. Puroindolines are effective in vivo in antifungal proteins and could be valuable new tools in the control of a wide range of fungal pathogens of crop plants. PMID:11605965

  10. Determination of lytic enzyme activities of indigenous Trichoderma isolates from Pakistan.

    PubMed

    Asad, Saeed Ahmad; Tabassum, Ayesha; Hameed, Abdul; Hassan, Fayyaz Ul; Afzal, Aftab; Khan, Sabaz Ali; Ahmed, Rafiq; Shahzad, Muhammad

    2015-12-01

    This study investigated lytic enzyme activities in three indigenous Trichoderma strains namely, Trichoderma asperellum, Trichoderma harzianum and Trichoderma sp. Native Trichoderma strains and a virulent strain of Rhizoctonia solani isolated from infected bean plants were also included in the study. Enzyme activities were determined by measuring sugar reduction by dinitrosalicylic acid (DNS) method using suitable substrates. The antagonists were cultured in minimal salt medium with the following modifications: medium A (1 g of glucose), medium B (0.5 g of glucose + 0.5 g of deactivated R. solani mycelia), medium C (1.0 g of deactivated respective antagonist mycelium) and medium D (1 g of deactivated R. solani mycelia). T asperellum showed presence of higher amounts of chitinases, ?-1, 3-glucanases and xylanases in extracellular protein extracts from medium D as compared to medium A. While, the higher activities of glucosidases and endoglucanses were shown in medium D extracts by T. harzianum. ?-glucosidase activities were lower compared with other enzymes; however, activities of the extracts of medium D were significantly different. T. asperellum exhibited maximum inhibition (97.7%). On the other hand, Trichoderma sp. did not show any effect on mycelia growth of R. solani on crude extract. PMID:26691463

  11. The induction of Ethylene response factor 3 (ERF3) in potato as a result of co-inoculation with Pseudomonas sp. R41805 and Rhizophagus irregularis MUCL 41833 – a possible role in plant defense

    PubMed Central

    Velivelli, Siva LS; Lojan, Paul; Cranenbrouck, Sylvie; de Boulois, Hervé Dupré; Suarez, Juan Pablo; Declerck, Stéphane; Franco, Javier; Prestwich, Barbara Doyle

    2015-01-01

    Colonization of plant rhizosphere/roots by beneficial microorganisms (e.g. plant growth promoting rhizobacteria – PGPR, arbuscular mycorrhizal fungi – AMF) confers broad-spectrum resistance to virulent pathogens and is known as induced systemic resistance (ISR) and mycorrhizal-induced resistance (MIR). ISR or MIR, an indirect mechanism for biocontrol, involves complex signaling networks that are regulated by several plant hormones, the most important of which are salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). In the present study, we investigated if inoculation of potato plantlets with an AMF (Rhizophagus irregularis MUCL 41833) and a PGPR (Pseudomonas sp R41805) either alone or in combination, could elicit host defense response genes in the presence or absence of Rhizoctonia Solani EC-1, a major potato pathogen. RT-qPCR revealed the significant expression of ethylene response factor 3 (EFR3) in mycorrhized potato plantlets inoculated with Pseudomonas sp R41805 and also in mycorrhized potato plantlets inoculated with Pseudomonas sp R41805 and challenged with R. solani. The significance of ethylene response factors (ERFs) in pathogen defense has been well documented in the literature. The results of the present study suggest that the dual inoculation of potato with PGPR and AMF may play a part in the activation of plant systemic defense systems via ERF3. PMID:25723847

  12. Bioactive lipopeptides of ice-nucleating snow bacterium Pseudomonas syringae strain 31R1.

    PubMed

    Fiore, Alberto; Mannina, Luisa; Sobolev, Anatoli P; Salzano, Anna Maria; Scaloni, Andrea; Grgurina, Ingeborg; Fullone, Maria Rosaria; Gallo, Monica; Swasey, Camille; Fogliano, Vincenzo; Takemoto, Jon Y

    2008-09-01

    The production of secondary metabolite lipopeptides by ice-nucleating Pseudomonas syringae strain 31R1 was investigated. Pseudomonas syringae strain 31R1 is a rifampicin-resistant derivative of P. syringae no. 31 used for the commercial production of snow. It is shown that P. syringae strain 31R1 produces antifungal lipodepsipeptides, syringomycins E and G, and, in addition, a novel and unique lipopeptide, peptin31. Spectroscopic and spectrometric analyses revealed that peptin31 is a linear undecalipopeptide with sequence identities to N- and C-terminal portions but lacking 11 amino acids of known lipodepsipeptide syringopeptin SPPhv. Peptin31 displayed antifungal activities against Rhodotorula pilimanae, Rhizoctonia solani, and Trichoderma harzianum and also hemolytic and antibacterial activities. Extracts of P. syringae strain 31R1 grown in medium with chloride were fungicidal, but not when grown without chloride. The latter extracts lacked peptin 31 and contained des-chloro forms of syringomycins E and G with low antifungal activities. Thus, the three lipopeptides account for the fungicidal properties of P. syringae 31R1 extracts. The occurrence of these bioactive metabolites should be considered when P. syringae no. 31 and its derivatives are used in products for making artificial snow. PMID:18789127

  13. Prospecting cold deserts of north western Himalayas for microbial diversity and plant growth promoting attributes.

    PubMed

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Saxena, Anil Kumar

    2015-06-01

    Microbial communities in different samples collected from cold deserts of north western Himalayas, India, were analyzed using 16S rRNA gene sequencing and phospholipid fatty acids (PLFA) analysis. A total of 232 bacterial isolates were characterized employing 16S rDNA-Amplified Ribosomal DNA Restriction Analysis with the three restriction endonucleases Alu I, Msp I and Hae III, which led to formation of 29-54 groups for the different sites, adding up to169 groups. 16S rRNA gene based phylogenetic analysis, revealed that 82 distinct species of 31 different genera, belonged to four phyla Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. PLFA profiling was performed for concerned samples which gave an estimate of microbial communities without cultivating the microorganisms. PLFA analysis led to characterization of diverse group of microbes in different samples such as gram-negative, gram-positive bacteria, actinomycetes, cyanobacteria, anaerobic bacteria, sulphate reducing bacteria and fungi. The representative strains were screened for their plant growth promoting attributes, which included production of ammonia, HCN, gibberellic acid, IAA and siderophore; solubilization of phosphorus and activity of ACC deaminase. In vitro antifungal activity assay was performed against Rhizoctonia solani and Macrophomina phaseolina. Cold adapted microorganisms may serve as inoculants for crops growing under cold climatic conditions. To our knowledge, this is the first report for the presence of Arthrobacter nicotianae, Brevundimonas terrae, Paenibacillus tylopili and Pseudomonas cedrina in cold deserts and exhibit multifunctional PGP attributes at low temperatures. PMID:25575970

  14. Marine isolates of Trichoderma spp. as potential halotolerant agents of biological control for arid-zone agriculture.

    PubMed

    Gal-Hemed, Inbal; Atanasova, Lea; Komon-Zelazowska, Monika; Druzhinina, Irina S; Viterbo, Ada; Yarden, Oded

    2011-08-01

    The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents. PMID:21666030

  15. Lignin and lignans in plant defence: insight from expression profiling of cinnamyl alcohol dehydrogenase genes during development and following fungal infection in Populus.

    PubMed

    Bagniewska-Zadworna, Agnieszka; Barakat, Abdelali; Lakomy, Piotr; Smoli?ski, Dariusz J; Zadworny, Marcin

    2014-12-01

    Cinnamyl alcohol dehydrogenase (CAD) catalyses the final step in the biosynthesis of monolignol, the main component of lignin. Lignins, deposited in the secondary cell wall, play a role in plant defence against pathogens. We re-analysed the phylogeny of CAD/CAD-like genes using sequences from recently sequenced genomes, and analysed the temporal and spatial expression profiles of CAD/CAD-like genes in Populus trichocarpa healthy and infected plants. Three fungal pathogens (Rhizoctonia solani, Fusarium oxysporum, and Cytospora sp.), varying in lifestyle and pathogenicity, were used for plant infection. Phylogenetic analyses showed that CAD/CAD-like genes were distributed in classes represented by all members from angiosperm lineages including basal angiosperms and Selaginella. The analysed genes showed different expression profiles during development and demonstrated that three genes were involved in primary xylem maturation while five may function in secondary xylem formation. Expression analysis following inoculation with fungal pathogens, showed that five genes were induced in either stem or leaves. These results add further evidence that CAD/CAD-like genes have evolved specialised functions in plant development and defence against various pest and pathogens. Two genes (PoptrCAD11 and PoptrCAD15), which were induced under various stresses, could be treated as universal markers of plant defence using lignification or lignan biosynthesis. PMID:25443838

  16. Functional Analysis of the Trichoderma harzianum nox1 Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum?†

    PubMed Central

    Montero-Barrientos, M.; Hermosa, R.; Cardoza, R. E.; Gutiérrez, S.; Monte, E.

    2011-01-01

    The synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. The nox1 gene of Trichoderma harzianum was cloned, and its role in antagonism against phytopathogens was analyzed in nox1-overexpressed transformants. The increased levels of nox1 expression in these transformants were accompanied by an increase in ROS production during their direct confrontation with Pythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays against P. ultimum the nox1-overexpressed transformants were more effective than the wild type, but not in assays against Botrytis cinerea or Rhizoctonia solani. A transcriptomic analysis using a Trichoderma high-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-type T. harzianum and P. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of a nox1-overexpressed transformant with this pathogen. Our results show that nox1 is involved in T. harzianum ROS production and antagonism against P. ultimum. PMID:21421791

  17. A novel fungal metabolite with beneficial properties for agricultural applications.

    PubMed

    Vinale, Francesco; Manganiello, Gelsomina; Nigro, Marco; Mazzei, Pierluigi; Piccolo, Alessandro; Pascale, Alberto; Ruocco, Michelina; Marra, Roberta; Lombardi, Nadia; Lanzuise, Stefania; Varlese, Rosaria; Cavallo, Pierpaolo; Lorito, Matteo; Woo, Sheridan L

    2014-01-01

    Trichoderma are ubiquitous soil fungi that include species widely used as biocontrol agents in agriculture. Many isolates are known to secrete several secondary metabolites with different biological activities towards plants and other microbes. Harzianic acid (HA) is a T. harzianum metabolite able to promote plant growth and strongly bind iron. In this work, we isolated from the culture filtrate of a T. harzianum strain a new metabolite, named isoharzianic acid (iso-HA), a stereoisomer of HA. The structure and absolute configuration of this compound has been determined by spectroscopic methods, including UV-Vis, MS, 1D and 2D NMR analyses. In vitro applications of iso-HA inhibited the mycelium radial growth of Sclerotinia sclerotiorum and Rhizoctonia solani. Moreover, iso HA improved the germination of tomato seeds and induced disease resistance. HPLC-DAD experiments showed that the production of HA and iso HA was affected by the presence of plant tissue in the liquid medium. In particular, tomato tissue elicited the production of HA but negatively modulated the biosynthesis of its analogue iso-HA, suggesting that different forms of the same Trichoderma secondary metabolite have specific roles in the molecular mechanism regulating the Trichoderma plant interaction. PMID:25006784

  18. Effect of Biocontrol Agent Pseudomonas fluorescens 2P24 on Soil Fungal Community in Cucumber Rhizosphere Using T-RFLP and DGGE

    PubMed Central

    Gao, Guanpeng; Yin, Danhan; Chen, Shengju; Xia, Fei; Yang, Jie; Li, Qing; Wang, Wei

    2012-01-01

    Fungi and fungal community play important roles in the soil ecosystem, and the diversity of fungal community could act as natural antagonists of various plant pathogens. Biological control is a promising method to protect plants as chemical pesticides may cause environment pollution. Pseudomonas fluorescens 2P24 had strong inhibitory on Rastonia solanacearum, Fusarium oxysporum and Rhizoctonia solani, etc., and was isolated from the wheat rhizosphere take-all decline soils in Shandong province, China. However, its potential effect on soil fungal community was still unknown. In this study, the gfp-labeled P. fluorescens 2P24 was inoculated into cucumber rhizosphere, and the survival of 2P24 was monitored weekly. The amount decreased from 108 to 105 CFU/g dry soils. The effect of 2P24 on soil fungal community in cucumber rhizosphere was investigated using T-RFLP and DGGE. In T-RFLP analysis, principle component analysis showed that the soil fungal community was greatly influenced at first, digested with restriction enzyme Hinf I and Taq I. However, there was little difference as digested by different enzymes. DGGE results demonstrated that the soil fungal community was greatly shocked at the beginning, but it recovered slowly with the decline of P. fluorescens 2P24. Four weeks later, there was little difference between the treatment and control. Generally speaking, the effect of P. fluorescens 2P24 on soil fungal community in cucumber rhizosphere was just transient. PMID:22359632

  19. Ieodoglucomide C and Ieodoglycolipid, New Glycolipids from a Marine-Derived Bacterium Bacillus licheniformis 09IDYM23.

    PubMed

    Tareq, Fakir Shahidullah; Lee, Hyi-Seung; Lee, Yeon-Ju; Lee, Jong Seok; Shin, Hee Jae

    2015-05-01

    Chemical examination of the ethyl acetate extract from the fermentation broth of the marine-derived bacterium Bacillus licheniformis resulted in the isolation of two new glycolipids, ieodoglucomide C (1) and ieodoglycolipid (2). The structural characterization of 1 and 2 was achieved by extensive spectroscopic evidence, including 2D NMR experiments. A combination of chemical derivatization techniques followed by NMR studies, LC-MS data analysis and a literature review was deployed for the establishment of the stereo-configurations of 1 and 2. Compounds 1 and 2 exhibited good antibiotic properties against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Salmonella typhi, Escherichia coli and Pseudomonas aeruginosa with MICs ranging from 0.01 to 0.05 ?M. Furthermore, the antifungal activity of 1 and 2 was evaluated against plant pathogenic fungi Aspergillus niger, Rhizoctonia solani, Botrytis cinerea and Colletotrichum acutatum as well as the human pathogen Candida albicans. Compounds 1 and 2 inhibited the mycelial growth of these pathogens with MIC values of 0.03-0.05 ?M, revealing that these compounds are good candidates for the development of new fungicides. PMID:25893812

  20. Novel, Synergistic Antifungal Combinations that Target Translation Fidelity.

    PubMed

    Moreno-Martinez, Elena; Vallieres, Cindy; Holland, Sara L; Avery, Simon V

    2015-01-01

    There is an unmet need for new antifungal or fungicide treatments, as resistance to existing treatments grows. Combination treatments help to combat resistance. Here we develop a novel, effective target for combination antifungal therapy. Different aminoglycoside antibiotics combined with different sulphate-transport inhibitors produced strong, synergistic growth-inhibition of several fungi. Combinations decreased the respective MICs by ?8-fold. Synergy was suppressed in yeast mutants resistant to effects of sulphate-mimetics (like chromate or molybdate) on sulphate transport. By different mechanisms, aminoglycosides and inhibition of sulphate transport cause errors in mRNA translation. The mistranslation rate was stimulated up to 10-fold when the agents were used in combination, consistent with this being the mode of synergistic action. A range of undesirable fungi were susceptible to synergistic inhibition by the combinations, including the human pathogens Candida albicans, C. glabrata and Cryptococcus neoformans, the food spoilage organism Zygosaccharomyces bailii and the phytopathogens Rhizoctonia solani and Zymoseptoria tritici. There was some specificity as certain fungi were unaffected. There was no synergy against bacterial or mammalian cells. The results indicate that translation fidelity is a promising new target for combinatorial treatment of undesirable fungi, the combinations requiring substantially decreased doses of active components compared to each agent alone. PMID:26573415

  1. Growth promoting influence of siderophore-producing Pseudomonas strains GRP3A and PRS9 in maize (Zea mays L.) under iron limiting conditions.

    PubMed

    Sharma, Alok; Johri, B N

    2003-01-01

    Maize seeds were bacterized with siderophore-producing pseudomonads with the goal to develop a system suitable for better iron uptake under iron-stressed conditions. Siderophore production was compared in fluorescent Pseudomonas spp. GRP3A, PRS9 and P. chlororaphis ATCC 9446 in standard succinate (SSM) and citrate (SCM) media. Succinate was better suited for siderophore production, however, deferration of media resulted in increased siderophore production in all the strains. Maximum siderophore level (216.23 microg/ml) was observed in strain PRS9 in deferrated SSM after 72 h of incubation. Strains GRP3A and PRS9 were used for plant growth promotion experiments. Strains GRP3A and PRS9 were also antagonistic against the phytopathogens, Colletotrichum dematium, Rhizoctonia solani and Sclerotium rolfsii. Bacterization of maize seeds with strains GRP3A and PRS9 showed significant increase in germination percentage and plant growth. Maximum shoot and root length and dry weight were observed with 10 microM Fe3+ along with bacterial inoculants suggesting application of siderophore producing plant growth promoting rhizobacterial strains in crop productivity in calcareous soil system. PMID:14521234

  2. Activation of Pathogenesis-related Genes by the Rhizobacterium, Bacillus sp. JS, Which Induces Systemic Resistance in Tobacco Plants

    PubMed Central

    Kim, Ji-Seong; Lee, Jeongeun; Lee, Chan-hui; Woo, Su Young; Kang, Hoduck; Seo, Sang-Gyu; Kim, Sun-Hyung

    2015-01-01

    Plant growth promoting rhizobacteria (PGPR) are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR) gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding ?-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA) induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression. PMID:26060440

  3. Microemulsion Formulation of Carbendazim and Its In Vitro Antifungal Activities Evaluation

    PubMed Central

    Leng, Pengfei; Zhang, Zhiming; Li, Qian; Zhao, Maojun; Pan, Guangtang

    2014-01-01

    The fungus Rhizoctonia solani Kuhn is a widespread and destructive plant pathogen with a very broad host range. Although various pathogens, including R. solani, have been traditionally controlled using chemical pesticides, their use faces drawbacks such as environmental pollution, development of pesticide resistance, and other negative effects. Carbendazim is a well-known antifungal agent capable of controlling a broad range of plant diseases, but its use is hampered by its poor aqueous solubility. In this study, we describe an environmentally friendly pharmaceutical microemulsion system using carbendazim as the active ingredient, chloroform and acetic acid as solvents, and the surfactants HSH and 0204 as emulsifiers. This system increased the solubility of carbendazim to 30 g/L. The optimal microemulsion formulation was determined based on a pseudo-ternary phase diagram; its physicochemical characteristics were also tested. The cloud point was greater than 90°C and it was resistant to freezing down to ?18°C, both of which are improvements over the temperature range in which pure carbendazim can be used. This microemulsion meets the standard for pesticide microemulsions and demonstrated better activity against R. solani AG1-IA, relative to an aqueous solution of pure carbendazim (0.2 g/L). The mechanism of activity was reflected in the inhibition of against R. solani AG1-IA including mycelium growth, and sclerotia formation and germination were significantly better than that of 0.2 g/L carbendazim water solution according to the results of t-test done by SPSS 19. PMID:25310219

  4. Endophytic bacterial communities in ginseng and their antifungal activity against pathogens.

    PubMed

    Cho, Kye Man; Hong, Su Young; Lee, Sun Mi; Kim, Yong Hee; Kahng, Goon Gjung; Lim, Yong Pyo; Kim, Hoon; Yun, Han Dae

    2007-08-01

    Plant roots are associated with diverse communities of endophytic bacteria which do not exert adverse effects. The diversity of bacterial endophytes associated with ginseng roots cultivated in three different areas in Korea was investigated. Sixty-three colonies were isolated from the interior of ginseng roots. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolates belonged to three major phylogenetic groups: the high G+C Gram-positive bacteria (HGCGPB), low G+C Gram-positive bacteria (LGCGPB), and the Proteobacteria. The dominant species at the three different ginseng growing areas were: HGCGPB at Ganghwa (55.0%), LGCGPB at Geumsan (45.5%), and Proteobacteria at Jinan (61.9%). Most cellulase-, xylanase-, and pectinase-producing colonies among the isolates belong to the LGCGPB group, except for Pectobacterium carotovora which belonged to the Proteobacteria. The 13 isolates belonging to LGCGPB and Proteobacteria were assessed for their antifungal activity against phytopathogenic fungi such as Rhizoctonia solani. Among them, Paenibacillus polymyxa GS01, Bacillus sp. GS07, and Pseudomonas poae JA01 show potential activity as biocontrol agents against phytopathogenic fungi. Finally, most of the low G+C Gram-positive bacteria with antifungal activity against phytopathogenic microorganisms showed cellulolytic enzyme activity while some Proteobacteria with the antifungal activity and the high G+C Gram-positive bacteria did not show any cellulolytic activity. PMID:17492474

  5. Effects of Bacillus amyloliquefaciens FZB42 on Lettuce Growth and Health under Pathogen Pressure and Its Impact on the Rhizosphere Bacterial Community

    PubMed Central

    Rändler, Manuela; Schmid, Michael; Junge, Helmut; Borriss, Rainer; Hartmann, Anton; Grosch, Rita

    2013-01-01

    The soil-borne pathogen Rhizoctonia solani is responsible for crop losses on a wide range of important crops worldwide. The lack of effective control strategies and the increasing demand for organically grown food has stimulated research on biological control. The aim of the present study was to evaluate the rhizosphere competence of the commercially available inoculant Bacillus amyloliquefaciens FZB42 on lettuce growth and health together with its impact on the indigenous rhizosphere bacterial community in field and pot experiments. Results of both experiments demonstrated that FZB42 is able to effectively colonize the rhizosphere (7.45 to 6.61 Log 10 CFU g?1 root dry mass) within the growth period of lettuce in the field. The disease severity (DS) of bottom rot on lettuce was significantly reduced from severe symptoms with DS category 5 to slight symptom expression with DS category 3 on average through treatment of young plants with FZB42 before and after planting. The 16S rRNA gene based fingerprinting method terminal restriction fragment length polymorphism (T-RFLP) showed that the treatment with FZB42 did not have a major impact on the indigenous rhizosphere bacterial community. However, the bacterial community showed a clear temporal shift. The results also indicated that the pathogen R. solani AG1-IB affects the rhizosphere microbial community after inoculation. Thus, we revealed that the inoculant FZB42 could establish itself successfully in the rhizosphere without showing any durable effect on the rhizosphere bacterial community. PMID:23935892

  6. Protozoa Drive the Dynamics of Culturable Biocontrol Bacterial Communities

    PubMed Central

    Müller, Maren Stella; Scheu, Stefan; Jousset, Alexandre

    2013-01-01

    Some soil bacteria protect plants against soil-borne diseases by producing toxic secondary metabolites. Such beneficial biocontrol bacteria can be used in agricultural systems as alternative to agrochemicals. The broad spectrum toxins responsible for plant protection also inhibit predation by protozoa and nematodes, the main consumers of bacteria in soil. Therefore, predation pressure may favour biocontrol bacteria and contribute to plant health. We analyzed the effect of Acanthamoeba castellanii on semi-natural soil bacterial communities in a microcosm experiment. We determined the frequency of culturable bacteria carrying genes responsible for the production of the antifungal compounds 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin (PRN) and hydrogen cyanide (HCN) in presence and absence of A. castellanii. We then measured if amoebae affected soil suppressiveness in a bioassay with sugar beet seedlings confronted to the fungal pathogen Rhizoctonia solani. Amoebae increased the frequency of both DAPG and HCN positive bacteria in later plant growth phases (2 and 3 weeks), as well as the average number of biocontrol genes per bacterium. The abundance of DAPG positive bacteria correlated with disease suppression, suggesting that their promotion by amoebae may enhance soil health. However, the net effect of amoebae on soil suppressiveness was neutral to slightly negative, possibly because amoebae slow down the establishment of biocontrol bacteria on the recently emerged seedlings used in the assay. The results indicate that microfaunal predators foster biocontrol bacterial communities. Understanding interactions between biocontrol bacteria and their predators may thus help developing environmentally friendly management practices of agricultural systems. PMID:23840423

  7. Mycotoxicoses of ruminants and horses.

    PubMed

    Riet-Correa, Franklin; Rivero, Rodolfo; Odriozola, Ernesto; Adrien, Maria de Lourdes; Medeiros, Rosane M T; Schild, Ana Lucia

    2013-11-01

    In the current study, mycotoxicoses of ruminants and horses are reviewed, with an emphasis on the occurrence of these diseases in South America. The main mycotoxicoses observed in grazing cattle include intoxications by indole-diterpenoid mycotoxins (Paspalum spp. contaminated by Claviceps paspali, Lolium perenne infected by Neotyphodium lolii, Cynodon dactylon infected by Claviceps cynodontis, and Poa huecu), gangrenous ergotism and dysthermic syndrome (hyperthermia) caused by Festuca arundinacea (syn. Festuca elatior) infected by Neotyphodium coenophialum (syn. Acremonium coenophialum), and photosensitization in pastures contaminated by toxigenic Pithomyces chartarum. Other mycotoxicoses in grazing cattle include slaframine toxicity in clover pastures infected by Rhizoctonia leguminicola and diplodiosis in cattle grazing in corn stubbles. The mycotoxicoses caused by contaminated concentrated food or byproducts in cattle include poisoning by toxins of Aspergillus clavatus, which contaminate barley or sugar beetroot by-products, gangrenous ergotism or dysthermic syndrome caused by wheat bran or wheat screenings contaminated with Claviceps purpurea, and acute respiratory distress caused by damaged sweet potatoes (Ipomoea batatas). The main mycotoxicosis of horses is leukoencephalomalacia caused by the fumonisins B1 and B2 produced by Fusarium spp. Poisoning by C. purpurea and F. elatior infected by N. coenophialum has also been reported as a cause of agalactia and neonatal mortality in mares. Slaframine toxicosis caused by the ingestion of alfalfa hay contaminated by R. leguminicola has also been reported in horses. PMID:24091682

  8. The Novel Lipopeptide Poaeamide of the Endophyte Pseudomonas poae RE*1-1-14 Is Involved in Pathogen Suppression and Root Colonization.

    PubMed

    Zachow, Christin; Jahanshah, Ghazaleh; de Bruijn, Irene; Song, Chunxu; Ianni, Federica; Pataj, Zoltán; Gerhardt, Heike; Pianet, Isabelle; Lämmerhofer, Michael; Berg, Gabriele; Gross, Harald; Raaijmakers, Jos M

    2015-07-01

    Endophytic Pseudomonas poae strain RE*1-1-14 was originally isolated from internal root tissue of sugar beet plants and shown to suppress growth of the fungal pathogen Rhizoctonia solani both in vitro and in the field. To identify genes involved in its biocontrol activity, RE*1-1-14 random mutagenesis and sequencing led to the identification of a nonribosomal peptide synthetase (NRPS) gene cluster predicted to encode a lipopeptide (LP) with a 10-amino-acid peptide moiety. The two unlinked gene clusters consisted of three NRPS genes, designated poaA (cluster 1) and poaB and poaC (cluster 2), spanning approximately 33.7 kb. In silico analysis followed by chemical analyses revealed that the encoded LP, designated poaeamide, is a structurally new member of the orfamide family. Poaeamide inhibited mycelial growth of R. solani and different oomycetes, including Phytophthora capsici, P. infestans, and Pythium ultimum. The novel LP was shown to be essential for swarming motility of strain RE*1-1-14 and had an impact on root colonization of sugar beet seedlings The poaeamide-deficient mutant colonized the rhizosphere and upper plant cortex at higher densities and with more scattered colonization patterns than the wild type. Collectively, these results indicate that Pseudomonas poae RE*1-1-14 produces a structurally new LP that is relevant for its antagonistic activity against soilborne plant pathogens and for colonization of sugar beet roots. PMID:25761208

  9. Resistance to multiple tuber diseases expressed in somaclonal variants of the potato cultivar Russet Burbank.

    PubMed

    Thangavel, Tamilarasan; Steven Tegg, Robert; Wilson, Calum Rae

    2014-01-01

    Multiple disease resistance is an aim of many plant breeding programs. Previously, novel somatic cell selection was used to generate potato variants of "Russet Burbank" with resistance to common scab caused by infection with an actinomycete pathogen. Coexpression of resistance to powdery scab caused by a protozoan pathogen was subsequently shown. This study sought to define whether this resistance was effective against additional potato tuber diseases, black scurf, and tuber soft rot induced by fungal and bacterial pathogens. Pot trials and in vitro assays with multiple pathogenic strains identified significant resistance to both tuber diseases across the potato variants examined; the best clone A380 showed 51% and 65% reductions in disease severity to tuber soft rot and black scurf, respectively, when compared with the parent line. The resistance appeared to be tuber specific as no enhanced resistance was recorded in stolons or stem material when challenged Rhizoctonia solani that induces stolon pruning and stem canker. The work presented here suggests that morphological characteristics associated with tuber resistance may be the predominant change that has resulted from the somaclonal cell selection process, potentially underpinning the demonstrated broad spectrum of resistance to tuber invading pathogens. PMID:24523639

  10. Antifungal Activities of Copper(II) with Biosensitive Macrocyclic Schiff Base Ligands Derived from 4-Aminoantipyrine Derivatives

    PubMed Central

    Joseph, J.

    2009-01-01

    Novel copper(II) complexes have been synthesized from the macrocyclic Schiff bases derived from Knoevenagel condensed ?-ketoanilides (obtained by the condensation of acetoacetanilide and substituted benzaldehydes), 4-aminoantipyrine and o-phenylene diamine. The structural features have been determined from their analytical and spectral data. All the Cu(II) complexes exhibit square planar geometry. Their high molar conductance values support their 1 : 2 electrolytic nature. The magnetic moment data provide evidence for the monomeric nature of the complexes. The X-band ESR spectra of the [CuL1](OAc)2 in DMSO solution at 300 and 77 K were recorded and their salient features are reported. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by well diffusion method. A comparative study of inhibition values of the Schiff bases and their complexes indicate that complexes exhibit higher antimicrobial activity than the Schiff bases. Copper ions proved to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium. PMID:23983523

  11. Chiral triazole fungicide difenoconazole: absolute stereochemistry, stereoselective bioactivity, aquatic toxicity, and environmental behavior in vegetables and soil.

    PubMed

    Dong, Fengshou; Li, Jing; Chankvetadze, Bezhan; Cheng, Yongpu; Xu, Jun; Liu, Xingang; Li, Yuanbo; Chen, Xiu; Bertucci, Carlo; Tedesco, Daniele; Zanasi, Riccardo; Zheng, Yongquan

    2013-04-01

    In this study, the systemic assessments of the stereoisomers of triazole fungicide difenoconazole are reported for the first time, including absolute stereochemistry, stereoselective bioactivity toward pathogens (Alternaria sonali, Fulvia fulva, Botrytis cinerea, and Rhizoctonia solani), and toxicity toward aquatic organisms (Scenedesmus obliquus, Daphnia magna, and Danio rerio). Moreover, the stereoselective degradation of difenoconazole in vegetables (cucumber, Cucumis sativus and tomato, Lycopersicon esculentum) under field conditions and in soil under laboratory-controlled conditions (aerobic and anaerobic) was investigated. There were 1.33-24.2-fold and 1.04-6.78-fold differences in bioactivity and toxicity, respectively. Investigations on the stereoselective degradation of difenoconazole in vegetables showed that the highest-toxic and lowest-bioactive (2S,4S)-stereoisomer displays a different enrichment behavior in different plant species. Under aerobic or anaerobic conditions, (2R,4R)- and (2R,4S)-difenoconazole were preferentially degraded in the soil. Moreover, difenoconazole was configurationally stable in the test soil matrices. On the basis of biological activity, ecotoxicity, and environmental behavior, it is likely that the use of pure (2R,4S)-difenoconazole instead of the commercial stereoisomer mix may help to increase the bioactivity and reduce environmental pollution. PMID:23451708

  12. Anti-fungal activity of cold and hot water extracts of spices against fungal pathogens of Roselle (Hibiscus sabdariffa) in vitro.

    PubMed

    Touba, Eslaminejad Parizi; Zakaria, Maziah; Tahereh, Eslaminejad

    2012-02-01

    Crude extracts of seven spices, viz. cardamom, chilli, coriander, onion, garlic, ginger, and galangale were made using cold water and hot water extraction and they were tested for their anti-fungal effects against the three Roselle pathogens i.e. Phoma exigua, Fusarium nygamai and Rhizoctonia solani using the 'poisoned food technique'. All seven spices studied showed significant anti-fungal activity at three concentrations (10, 20 and 30% of the crude extract) in-vitro. The cold water extract of garlic exhibited good anti-fungal activity against all three tested fungi. In the case of the hot water extracts, garlic and ginger showed the best anti-fungal activity. Of the two extraction methods, cold water extraction was generally more effective than hot water extraction in controlling the pathogens. Against P. exigua, the 10% cold water extracts of galangale, ginger, coriander and cardamom achieved total (100%) inhibition of pathogen mycelial growth. Total inhibition of F. nygamai mycelial growth was similarly achieved with the 10% cold water extracts garlic. Against R. solani, the 10% cold water extract of galangale was effective in imposing 100% inhibition. Accordingly, the 10% galangale extract effectively controlled both P. exigua and R. solani in vitro. None of the hot water extracts of the spices succeeded in achieving 100% inhibition of the pathogen mycelial growth. PMID:22138549

  13. Comparative Analyses of Exoproteinases Produced by Three Phytopathogenic Microorganisms

    PubMed Central

    Valueva, Tatiana A.; Kudryavtseva, Natalia N.; Sof'in, Alexis V.; Revina, Tatiana A.; Gvozdeva, Ekaterina L.; Ievleva, Elena V.

    2011-01-01

    Proteinases secreted by the oomycete Phytophthora infestans (Mont.) de Bary, Rhizoctonia solani, and Fusarium culmorum belonging to different families of fungi have been studied to determine if the exoenzyme secretion depends on the environmental conditions and the phylogenetic position of the pathogen. The substrate specificity of the extracellular proteinases of F. culmorum, R. solani, and P. infestans and their sensitivity to the action of synthetic and protein inhibitors suggest that they contain trypsin-like and subtilisin-like enzymes regardless of culture medium composition. The relation of trypsin-like and subtilisin-like enzymes is dependent on the culture medium composition, especially on the form of nitrogen nutrition, particularly in the case of the exoenzymes secreted by R. solani. Phylogenetic analyses have shown that the exoproteinase set of ascomycetes and oomycetes has more similarities than basidiomycetes although they are more distant relatives. Our data suggests that the multiple proteinases secreted by pathogenic fungi could play different roles in pathogenesis, increasing the adaptability and host range, or could have different functions in survival in various ecological habitats outside the host. PMID:22567343

  14. Novel, Synergistic Antifungal Combinations that Target Translation Fidelity

    PubMed Central

    Moreno-Martinez, Elena; Vallieres, Cindy; Holland, Sara L.; Avery, Simon V.

    2015-01-01

    There is an unmet need for new antifungal or fungicide treatments, as resistance to existing treatments grows. Combination treatments help to combat resistance. Here we develop a novel, effective target for combination antifungal therapy. Different aminoglycoside antibiotics combined with different sulphate-transport inhibitors produced strong, synergistic growth-inhibition of several fungi. Combinations decreased the respective MICs by ?8-fold. Synergy was suppressed in yeast mutants resistant to effects of sulphate-mimetics (like chromate or molybdate) on sulphate transport. By different mechanisms, aminoglycosides and inhibition of sulphate transport cause errors in mRNA translation. The mistranslation rate was stimulated up to 10-fold when the agents were used in combination, consistent with this being the mode of synergistic action. A range of undesirable fungi were susceptible to synergistic inhibition by the combinations, including the human pathogens Candida albicans, C. glabrata and Cryptococcus neoformans, the food spoilage organism Zygosaccharomyces bailii and the phytopathogens Rhizoctonia solani and Zymoseptoria tritici. There was some specificity as certain fungi were unaffected. There was no synergy against bacterial or mammalian cells. The results indicate that translation fidelity is a promising new target for combinatorial treatment of undesirable fungi, the combinations requiring substantially decreased doses of active components compared to each agent alone. PMID:26573415

  15. The Role of Antioxidant Enzymes in Adaptive Responses to Sheath Blight Infestation under Different Fertilization Rates and Hill Densities

    PubMed Central

    Wan, Xuejie; Shah, Farooq; Fahad, Shah; Huang, Jianliang

    2014-01-01

    Sheath blight of rice, caused by Rhizoctonia solani, is one of the most devastating rice diseases worldwide. No rice cultivar has been found to be completely resistant to this fungus. Identifying antioxidant enzymes activities (activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) and malondialdehyde content (MDA) responding to sheath blight infestation is imperative to understand the defensive mechanism systems of rice. In the present study, two inoculation methods (toothpick and agar block method) were tested in double-season rice. Toothpick method had greater lesion length than agar block method in late season. A higher MDA content was found under toothpick method compared with agar block method, which led to greater POD and SOD activities. Dense planting caused higher lesion length resulting in a higher MDA content, which also subsequently stimulated higher POD and SOD activity. Sheath blight severity was significantly related to the activity of antioxidant enzyme during both seasons. The present study implies that rice plants possess a system of antioxidant protective enzymes which helps them in adaptation to sheath blight infection stresses. Several agronomic practices, such as rational use of fertilizers and optimum planting density, involved in regulating antioxidant protective enzyme systems can be regarded as promising strategy to suppress the sheath blight development. PMID:25136671

  16. Antimicrobial and insecticidal protein isolated from seeds of Clitoria ternatea, a tropical forage legume.

    PubMed

    Kelemu, Segenet; Cardona, César; Segura, Gustavo

    2004-12-01

    The tropical forage legume Clitoria ternatea (L.) has important agronomic traits such as adaptation to a wide range of soil conditions and resistance to drought. It is resistant to a number of pathogens and pests. These important traits gave us reasons to look more closely at the plant. A highly basic small protein was purified from seeds of C. ternatea to homogeneity by using ultrafiltration with Centricon-3 membrane tubes and preparative granulated-bed isoelectric focusing (IEF). A single protein band was obtained on both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and IEF gels. The protein, designated 'finotin', has broad and potent inhibitory effect on the growth of various important fungal pathogens of plants, namely Rhizoctonia solani, Fusarium solani, Colletotrichum lindemuthianum, Lasiodiplodia theobromae, Pyricularia grisea, Bipolaris oryzae and Colletotrichum gloeosporioides. It also inhibits the common bean bacterial blight pathogen Xanthomonas axonopodis pv. phaseoli. Moreover, finotin has powerful inhibitory properties against the bean bruchids Zabrotes subfasciatus and Acanthoscelides obtectus. PMID:15694280

  17. Molecular cloning, structural analysis, and expression in Escherichia coli of a chitinase gene from Enterobacter agglomerans.

    PubMed Central

    Chernin, L S; De la Fuente, L; Sobolev, V; Haran, S; Vorgias, C E; Oppenheim, A B; Chet, I

    1997-01-01

    The gene chiA, which codes for endochitinase, was cloned from a soilborne Enterobacter agglomerans. Its complete sequence was determined, and the deduced amino acid sequence of the enzyme designated Chia_Entag yielded an open reading frame coding for 562 amino acids of a 61-kDa precursor protein with a putative leader peptide at its N terminus. The nucleotide and polypeptide sequences of Chia_Entag showed 86.8 and 87.7% identity with the corresponding gene and enzyme, Chia_Serma, of Serratia marcescens, respectively. Homology modeling of Chia_Entag's three-dimensional structure demonstrated that most amino acid substitutions are at solvent-accessible sites. Escherichia coli JM109 carrying the E. agglomerans chiA gene produced and secreted Chia_Entag. The antifungal activity of the secreted endochitinase was demonstrated in vitro by inhibition of Fusarium oxysporum spore germination. The transformed strain inhibited Rhizoctonia solani growth on plates and the root rot disease caused by this fungus in cotton seedlings under greenhouse conditions. PMID:9055404

  18. New insights into membrane-active action in plasma membrane of fungal hyphae by the lipopeptide antibiotic bacillomycin L.

    PubMed

    Zhang, Bao; Dong, Chunjuan; Shang, Qingmao; Han, Yuzhu; Li, Pinglan

    2013-09-01

    Bacillomycin L, a natural iturinic lipopeptide produced by Bacillus amyloliquefaciens, is characterized by strong antifungal activities against a variety of agronomically important filamentous fungi including Rhizoctonia solani Kühn. Prior to this study, the role of membrane permeabilization in the antimicrobial activity of bacillomycin L against plant pathogenic fungi had not been investigated. To shed light on the mechanism of this antifungal activity, the permeabilization of R. solani hyphae by bacillomycin L was investigated and compared with that by amphotericin B, a polyene antibiotic which is thought to act primarily through membrane disruption. Our results derived from electron microscopy, various fluorescent techniques and gel retardation experiments revealed that the antifungal activity of bacillomycin L may be not solely a consequence of fungal membrane permeabilization, but related to the interaction of it with intracellular targets. Our findings provide more insights into the mode of action of bacillomycin L and other iturins, which could in turn help to develop new or improved antifungal formulations or result in novel strategies to prevent fungal spoilage. PMID:23756779

  19. Responses of beneficial Bacillus amyloliquefaciens SQR9 to different soilborne fungal pathogens through the alteration of antifungal compounds production

    PubMed Central

    Li, Bing; Li, Qing; Xu, Zhihui; Zhang, Nan; Shen, Qirong; Zhang, Ruifu

    2014-01-01

    Bacillus amyloliquefaciens SQR9 exhibited predominantly antagonistic activities against a broad range of soilborne pathogens. The fungi-induced SQR9 extracts possess stronger antifungal activities compared with SQR9 monoculture extracts. To investigate how SQR9 fine-tunes lipopeptides (LPs) and a siderophore bacillibactin production to control different fungal pathogens, LPs and bacillibactin production and transcription of the respective encoding genes in SQR9 were measured and compared with six different soilborne fungal pathogens. SQR9 altered its spectrum of antifungal compounds production responding to different fungal pathogen. Bacillomycin D was the major LP produced when SQR9 was confronted with Fusarium oxysporum. Fengycin contributed to the antagonistic activity against Verticillium dahliae kleb, Fusarium oxysporum, Fusarium solani, and Phytophthora parasitica. Surfactin participated in the antagonistic process against Sclerotinia sclerotiorum, Rhizoctonia solani, and Fusarium solani. Bacillibactin was up-regulated when SQR9 was confronted with all tested fungi. The reduction in antagonistic activities of three LP and bacillibactin deficient mutants of SQR9 when confronted with the six soilborne fungal pathogens provided further evidence of the contribution of LPs and bacillibactin in controlling fungal pathogens. These results provide a new understanding of specific cues in bacteria-fungi interactions and provide insights for agricultural applications. PMID:25484880

  20. Enhanced micropropagation response and biocontrol effect of Azospirillum brasilense Sp245 on Prunus cerasifera L. clone Mr.S 2/5 plants.

    PubMed

    Russo, Anna; Vettori, Lorenzo; Felici, Cristiana; Fiaschi, Grazia; Morini, Stefano; Toffanin, Annita

    2008-04-30

    Inoculation with Azospirillum brasilense Sp245 exerts beneficial effects on micropropagated plants of Prunus cerasifera L. clone Mr.S 2/5, as seen in the results of a comparative analysis of inoculated and non-inoculated explants, during both the rooting and acclimatation phases. The presence of Azospirillum brasilense Sp245 increased root system, root hair biomass production and apical activity. Although the presence of the bacteria had a positive effect on rooting, the addition of indolebutyric acid (IBA) to Murashige and Skoog (MS) medium was seen as indispensable in order to promote the rooting of explants. Aside from the promotion of plant growth, A. brasilense Sp245 protects plants against pathogen attacks, such as Rhizoctonia spp., with a plant survival rate of nearly 100% vs. 0% as seen in the negative control. The biocontrol effect of A. brasilense Sp245 on the fungal rhizospheric community has been confirmed by denaturing gradient gel electrophoresis (DGGE) profiles of the rhizospheric microbial community. This study indicates that A. brasilense Sp245 could be employed as a tool in plant biotechnology. PMID:18358553

  1. Purification and characterisation of an antifungal protein, MCha-Pr, from the intercellular fluid of bitter gourd (Momordica charantia) leaves.

    PubMed

    Zhang, Beibei; Xie, Chengjian; Wei, Yunming; Li, Jing; Yang, Xingyong

    2015-03-01

    An antifungal protein, designated MCha-Pr, was isolated from the intercellular fluid of bitter gourd (Momordica charantia) leaves during a screen for potent antimicrobial proteins from plants. The isolation procedure involved a combination of extraction, ammonium sulphate precipitation, gel filtration on Bio-Gel P-6, ion exchange chromatography on CM-Sephadex, an additional gel filtration on HiLoad 16/60 Superdex 30, and finally, HPLC on a SOURCE 5RPC column. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry indicated that the protein had a molecular mass of 25733.46Da. Automated Edman degradation was used to determine the N-terminal sequence of MCha-Pr, and the amino acid sequence was identified as V-E-Y-T-I-T-G-N-A-G-N-T-P-G-G. The MCha-Pr protein has some similarity to the pathogenesis-related proteins from Atropa belladonna (deadly nightshade), Solanum tuberosum (potato), Ricinus communis (castor bean), and Nicotiana tabacum (tobacco). Analysis of the circular dichroism spectra indicated that MCha-Pr predominantly contains ?-helix and ?-sheet structures. MCha-Pr had inhibitory effects towards a variety of fungal species and the 50% inhibition of fungal growth (IC50) for Alternaria brassicae, Cercospora personata, Fusarium oxysporum, Mucor sp., and Rhizoctonia solani are 33 ?M, 42 ?M, 37 ?M, 40 ?M, and 48 ?M, respectively. In addition, this antifungal protein can inhibit the germination of A. brassicae spores at 12.5 ?M. These results suggest that MCha-Pr in bitter gourd leaves plays a protective role against phytopathogens and has a wide antimicrobial spectrum. PMID:25245535

  2. Genome mining and metabolic profiling of the rhizosphere bacterium Pseudomonas sp. SH-C52 for antimicrobial compounds

    PubMed Central

    Van Der Voort, Menno; Meijer, Harold J. G.; Schmidt, Yvonne; Watrous, Jeramie; Dekkers, Ester; Mendes, Rodrigo; Dorrestein, Pieter C.; Gross, Harald; Raaijmakers, Jos M.

    2015-01-01

    The plant microbiome represents an enormous untapped resource for discovering novel genes and bioactive compounds. Previously, we isolated Pseudomonas sp. SH-C52 from the rhizosphere of sugar beet plants grown in a soil suppressive to the fungal pathogen Rhizoctonia solani and showed that its antifungal activity is, in part, attributed to the production of the chlorinated 9-amino-acid lipopeptide thanamycin (Mendes et al., 2011). To get more insight into its biosynthetic repertoire, the genome of Pseudomonas sp. SH-C52 was sequenced and subjected to in silico, mutational and functional analyses. The sequencing revealed a genome size of 6.3 Mb and 5579 predicted ORFs. Phylogenetic analysis placed strain SH-C52 within the Pseudomonas corrugata clade. In silico analysis for secondary metabolites revealed a total of six non-ribosomal peptide synthetase (NRPS) gene clusters, including the two previously described NRPS clusters for thanamycin and the 2-amino acid antibacterial lipopeptide brabantamide. Here we show that thanamycin also has activity against an array of other fungi and that brabantamide A exhibits anti-oomycete activity and affects phospholipases of the late blight pathogen Phytophthora infestans. Most notably, mass spectrometry led to the discovery of a third lipopeptide, designated thanapeptin, with a 22-amino-acid peptide moiety. Seven structural variants of thanapeptin were found with varying degrees of activity against P. infestans. Of the remaining four NRPS clusters, one was predicted to encode for yet another and unknown lipopeptide with a predicted peptide moiety of 8-amino acids. Collectively, these results show an enormous metabolic potential for Pseudomonas sp. SH-C52, with at least three structurally diverse lipopeptides, each with a different antimicrobial activity spectrum. PMID:26217324

  3. Expression of a Novel Antimicrobial Peptide Penaeidin4-1 in Creeping Bentgrass (Agrostis stolonifera L.) Enhances Plant Fungal Disease Resistance

    PubMed Central

    Zhou, Man; Hu, Qian; Li, Zhigang; Li, Dayong; Chen, Chin-Fu; Luo, Hong

    2011-01-01

    Background Turfgrass species are agriculturally and economically important perennial crops. Turfgrass species are highly susceptible to a wide range of fungal pathogens. Dollar spot and brown patch, two important diseases caused by fungal pathogens Sclerotinia homoecarpa and Rhizoctonia solani, respectively, are among the most severe turfgrass diseases. Currently, turf fungal disease control mainly relies on fungicide treatments, which raises many concerns for human health and the environment. Antimicrobial peptides found in various organisms play an important role in innate immune response. Methodology/Principal Findings The antimicrobial peptide - Penaeidin4-1 (Pen4-1) from the shrimp, Litopenaeus setiferus has been reported to possess in vitro antifungal and antibacterial activities against various economically important fungal and bacterial pathogens. In this study, we have studied the feasibility of using this novel peptide for engineering enhanced disease resistance into creeping bentgrass plants (Agrostis stolonifera L., cv. Penn A-4). Two DNA constructs were prepared containing either the coding sequence of a single peptide, Pen4-1 or the DNA sequence coding for the transit signal peptide of the secreted tobacco AP24 protein translationally fused to the Pen4-1 coding sequence. A maize ubiquitin promoter was used in both constructs to drive gene expression. Transgenic turfgrass plants containing different DNA constructs were generated by Agrobacterium-mediated transformation and analyzed for transgene insertion and expression. In replicated in vitro and in vivo experiments under controlled environments, transgenic plants exhibited significantly enhanced resistance to dollar spot and brown patch, the two major fungal diseases in turfgrass. The targeting of Pen4-1 to endoplasmic reticulum by the transit peptide of AP24 protein did not significantly impact disease resistance in transgenic plants. Conclusion/Significance Our results demonstrate the effectiveness of Pen4-1 in a perennial species against fungal pathogens and suggest a potential strategy for engineering broad-spectrum fungal disease resistance in crop species. PMID:21931807

  4. A Novel and Effective Streptomyces sp. N2 Against Various Phytopathogenic Fungi.

    PubMed

    Xu, Bo; Chen, Wei; Wu, Zhi-Ming; Long, Yue; Li, Kun-Tai

    2015-11-01

    Phytopathogenic fungi would induce a variety of plant diseases, resulting in a severe reduction of agricultural output. However, the current plant disease control is mainly dependent on the environmentally and healthily hazardous chemical fungicides. Thus, the present work aimed to isolate an effective antagonistic microorganism against various soilborne phytopathogenic fungi. By dual culture with Rhizoctonia solani, a novel Streptomyces specie, Streptomyces sp. N2, was screened out from a total of 167 isolated actinomycetes, which displayed a strong inhibitory effect on R. solani (26.85?±?1.35 mm of inhibition zone diameter). By means of macroporous resin and silica gel column chromatography coupled with preparative HPLC, an antifungal metabolite (3-methyl-3,5-amino-4-vinyl-2-pyrone, C6H7O2N) was isolated and purified from Streptomyces sp. N2. The bioassay results showed that the purified antifungal metabolite could not only possess a broad-spectrum inhibitory effect on a range of plant pathogenic fungi in vitro (e.g., R. solani, Pyricularia grisea, Fusarium oxysporum f. sp. niveum, F. oxysporum f. sp. vasinfectum, Penicillium italicum, and Colletotrichum gloeosporioides), but also had a significantly effective in vivo biocontrol efficacy on grape fruits anthracnose caused by C. gloeosporioides. Microscopic observation indicated that the antifungal metabolite from Streptomyces sp. N2 would exert its antimicrobial activity by disorganizing the cytoplasmic organelles of phytopathogenic fungi. The above results suggested that Streptomyces sp. N2 was one of promising fungicide for biocontrol of fungal plant diseases, especially due to its broad-spectrum and effective antagonist on various plant pathogens. PMID:26306529

  5. Genetic analysis of plant endophytic Pseudomonas putida BP25 and chemo-profiling of its antimicrobial volatile organic compounds.

    PubMed

    Sheoran, Neelam; Valiya Nadakkakath, Agisha; Munjal, Vibhuti; Kundu, Aditi; Subaharan, Kesavan; Venugopal, Vibina; Rajamma, Suseelabhai; Eapen, Santhosh J; Kumar, Aundy

    2015-04-01

    Black pepper associated bacterium BP25 was isolated from root endosphere of apparently healthy cultivar Panniyur-5 that protected black pepper against Phytophthora capsici and Radopholus similis - the major production constraints. The bacterium was characterized and mechanisms of its antagonistic action against major pathogens are elucidated. The polyphasic phenotypic analysis revealed its identity as Pseudomonas putida. Multi locus sequence typing revealed that the bacterium shared gene sequences with several other isolates representing diverse habitats. Tissue localization assays exploiting green fluorescence protein expression clearly indicated that PpBP25 endophytically colonized not only its host plant - black pepper, but also other distantly related plants such as ginger and arabidopsis. PpBP25 colonies could be enumerated from internal tissues of plants four weeks post inoculation indicated its stable establishment and persistence in the plant system. The bacterium inhibited broad range of pathogens such as Phytophthora capsici, Pythium myriotylum, Giberella moniliformis, Rhizoctonia solani, Athelia rolfsii, Colletotrichum gloeosporioides and plant parasitic nematode, Radopholus similis by its volatile substances. GC/MS based chemical profiling revealed presence of Heneicosane; Tetratetracontane; Pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl); Tetracosyl heptafluorobutyrate; 1-3-Eicosene, (E)-; 1-Heneicosanol; Octadecyl trifluoroacetate and 1-Pentadecene in PpBP25 metabolite. Dynamic head space GC/MS analysis of airborne volatiles indicated the presence of aromatic compounds such as 1-Undecene;Disulfide dimethyl; Pyrazine, methyl-Pyrazine, 2,5-dimethyl-; Isoamyl alcohol; Pyrazine, methyl-; Dimethyl trisulfide, etc. The work paved way for profiling of broad spectrum antimicrobial VOCs in endophytic PpBP25 for crop protection. PMID:25801973

  6. Isolate Identity Determines Plant Tolerance to Pathogen Attack in Assembled Mycorrhizal Communities

    PubMed Central

    Lewandowski, Thaddeus J.; Dunfield, Kari E.; Antunes, Pedro M.

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) are widespread soil microorganisms that associate mutualistically with plant hosts. AMF receive photosynthates from the host in return for various benefits. One of such benefits is in the form of enhanced pathogen tolerance. However, this aspect of the symbiosis has been understudied compared to effects on plant growth and its ability to acquire nutrients. While it is known that increased AMF species richness positively correlates with plant productivity, the relationship between AMF diversity and host responses to pathogen attack remains obscure. The objective of this study was to test whether AMF isolates can differentially attenuate the deleterious effects of a root pathogen on plant growth, whether the richest assemblage of AMF isolates provides the most tolerance against the pathogen, and whether AMF-induced changes to root architecture serve as a mechanism for improved plant disease tolerance. In a growth chamber study, we exposed the plant oxeye daisy (Leucanthemum vulgare) to all combinations of three AMF isolates and to the plant root pathogen Rhizoctonia solani. We found that the pathogen caused an 81% reduction in shoot and a 70% reduction in root biomass. AMF significantly reduced the highly deleterious effect of the pathogen. Mycorrhizal plants infected with the pathogen produced 91% more dry shoot biomass and 72% more dry root biomass relative to plants solely infected with R. solani. AMF isolate identity was a better predictor of AMF-mediated host tolerance to the pathogen than AMF richness. However, the enhanced tolerance response did not result from AMF-mediated changes to root architecture. Our data indicate that AMF communities can play a major role in alleviating host pathogen attack but this depends primarily on the capacity of individual AMF isolates to provide this benefit. PMID:23620744

  7. Antifungal Rhizosphere Bacteria Can increase as Response to the Presence of Saprotrophic Fungi

    PubMed Central

    de Boer, Wietse; Hundscheid, Maria P. J.; Klein Gunnewiek, Paulien J. A.; de Ridder-Duine, Annelies S.; Thion, Cecile; van Veen, Johannes A.; van der Wal, Annemieke

    2015-01-01

    Knowledge on the factors that determine the composition of bacterial communities in the vicinity of roots (rhizosphere) is essential to understand plant-soil interactions. Plant species identity, plant growth stage and soil properties have been indicated as major determinants of rhizosphere bacterial community composition. Here we show that the presence of saprotrophic fungi can be an additional factor steering rhizosphere bacterial community composition and functioning. We studied the impact of presence of two common fungal rhizosphere inhabitants (Mucor hiemalis and Trichoderma harzianum) on the composition of cultivable bacterial communities developing in the rhizosphere of Carex arenaria (sand sedge) in sand microcosms. Identification and phenotypic characterization of bacterial isolates revealed clear shifts in the rhizosphere bacterial community composition by the presence of two fungal strains (M. hiemalis BHB1 and T. harzianum PvdG2), whereas another M. hiemalis strain did not show this effect. Presence of both M. hiemalis BHB1 and T. harzianum PvdG2 resulted in a significant increase of chitinolytic and (in vitro) antifungal bacteria. The latter was most pronounced for M. hiemalis BHB1, an isolate from Carex roots, which stimulated the development of the bacterial genera Achromobacter and Stenotrophomonas. In vitro tests showed that these genera were strongly antagonistic against M. hiemalis but also against the plant-pathogenic fungus Rhizoctonia solani. The most likely explanation for fungal-induced shifts in the composition of rhizosphere bacteria is that bacteria are being selected which are successful in competing with fungi for root exudates. Based on the results we propose that measures increasing saprotrophic fungi in agricultural soils should be explored as an alternative approach to enhance natural biocontrol against soil-borne plant-pathogenic fungi, namely by stimulating indigenous antifungal rhizosphere bacteria. PMID:26393509

  8. Chemical composition and antifungal activity of essential oils from different tissues of Japanese Cedar (Cryptomeria japonica).

    PubMed

    Cheng, Sen-Sung; Lin, Huang-Yuan; Chang, Shang-Tzen

    2005-02-01

    In this study antifungal activities of essential oils from different tissues of Japanese cedar (Cryptomeria japonica D. Don) against four wood decay fungi and six tree pathogenic fungi were investigated. In addition, the yields of essential oils obtained by water distillation were compared and their constituents determined by GC-MS analyses. The yield of essential oils from four tissues of Japanese cedar is in the decreasing order of leaf (27.38 mL/kg) > bark (6.31 mL/kg) > heartwood (3.80 mL/kg) > sapwood (1.27 mL/kg). Results obtained from the antifungal tests demonstrate that the essential oil of Japanese cedar heartwood used against Laetiporus sulphureus and Trametes versicolor and sapwood essential oil used against L. sulphureus had strong antifungal activities at 500 mug/mL, with IC(50) values of 39, 91, and 94 microg/mL, respectively. Besides, the essential oils of Japanese cedar heartwood used against Rhizoctonia solani, Collectotrichum gloeosporioides, Fusarium solani, and Ganoderma australe had strong antifungal activities at 500 microg/mL, with IC(50) values of 65, 80, 80, and 110 microg/mL, respectively. GC-MS analyses showed that the sesquiterpene hydrocarbon compounds dominate in the essential oil from Japanese cedar heartwood, amounting to a total percentage of 82.56%, with the major compounds of delta-cadinene (18.60%), isoledene (12.41%), and gamma-muurolene (11.82%). It is proposed that the excellent antifungal activities of Japanese cedar heartwood essential oils might correlate with the presence of these compounds. PMID:15686410

  9. Biological control of potato black scurf by rhizosphere associated bacteria

    PubMed Central

    Tariq, Mohsin; Yasmin, Sumera; Hafeez, Fauzia Y.

    2010-01-01

    The present work was carried out to study the potential of plant rhizosphere associated bacteria for the biocontrol of potato black scurf disease caused by Rhizoctonia solani Khun AG-3. A total of twenty-eight bacteria isolated from diseased and healthy potato plants grown in the soil of Naran and Faisalabad, Pakistan were evaluated for their antagonistic potential. Nine bacterial strains were found to be antagonistic in vitro, reduced the fungal growth and caused the lysis of sclerotia of R. solani in dual culture assay as well as in extracellular metabolite efficacy test. The selected antagonistic strains were further tested for the production and efficacy of volatile and diffusible antibiotics, lytic enzymes and siderophores against R. solani. Selected antagonistic bacteria were also characterized for growth promoting attributes i.e., phosphate solubilization, nitrogen fixation and indole acetic acid production. Biocontrol efficacy and percent yield increase by these antagonists was estimated in greenhouse experiment. Statistical analysis showed that two Pseudomonas spp. StT2 and StS3 were the most effective with 65.1 and 73.9 percent biocontrol efficacy, as well as 87.3 and 98.3 percent yield increase, respectively. Potential antagonistic bacterial strain StS3 showed maximum homology to Pseudomonas sp. as determined by 16S rRNA gene sequencing. These results suggest that bacterial isolates StS3 and StT2 have excellent potential to be used as effective biocontrol agents promoting plant growth with reduced disease incidence. PMID:24031515

  10. [Antagonistic interactions between saprotrophic fungi and geohelminths. 1. Saprotrophic fungi in the biological control of phytopathogenic geohelminths].

    PubMed

    Mazurkiewicz-Zapa?owicz, Kinga; Ko?odziejczyk, Lidia

    2009-01-01

    The state of knowledge on the possible antagonism between soil saprotrophic fungi and phytopathogenic nematodes of the genera Meloidogyne, Heterodera, and Globodera is reviewed basing on the literature and our own research. Mycelial colonisation of various developmental stages of these geohelminths is the most common factor thought to reduce their populations in nature. The following parasitic fungi can be found on the cysts, eggs, as well as the larvae of the nematodes: Paecilomyces lilacinus, Verticillium chlamydosporium, Cylindrocarpon destructans, Pochonia chlamydosporia, Fusarium spp., and Penicillium spp. The fungi invade the nematodes, such as Heterodera, Globodera, or Meloidogyne, "passively" penetrating through the natural orifices of the cysts, eggs, and larvae of the host. Equally frequent, however, is a biochemical action of the fungi prior to colonisation, which is linked with production of mycotoxirls or hydrolytic enzymes. Such an active way of fungal penetration of various stages of the phytopathogenic nematodes has been observed in Pochonia chlamydosporia, Penicillium verrucosum var. cyclopium, P. frequentans, Sclerotinia rolfsii, Rhizoctonia solani, and Fusarium spp. Triacylglycerols (TAG), phenols, as well as trichothecene, T-2, have been found in the metabolites extracted from mycelia of these species. Predation by fungi is also a factor that may reduce a population of phytopathogenic nematodes. This form of antagonism is characteristic for nematicidal fungi of the genera Arthrobotrys and Dactylella. These fungi form shrinking rings and hooks in their mycelia by which the fungus entangles and paralyses a migrating form of nematode. Despite the fact that the antagonism between fungi and nematodes is a commonly occurring phenomenon observed in the soil, the nematicidal and nematotoxic properties of fungi have not a wide application in biological plant protection. Up till now, only the bionematicides based on Arthrobotrys robusta (Royal 300 and Royal 350) as well as Paecilomyces lilacinus (Biocon and PL Plus) have found its commercial application. PMID:19579778

  11. Acidophilic actinomycetes from rhizosphere soil: diversity and properties beneficial to plants.

    PubMed

    Poomthongdee, Nalin; Duangmal, Kannika; Pathom-aree, Wasu

    2015-02-01

    Three hundred and fifty-one isolates of actinomycetes were recovered from 21 rhizospheric soil samples using acidified media of pH 5.5. They were evaluated for their antifungal, siderophore production and phosphate solubilization activities. The total count of actinomycetes growing on acidified starch casein agar and Gause no. 1 agar were below 2.48 × 10(4)?CFU?g(-1) soil. Two hundred and twelve isolates were assigned to acidophiles and the remaining 139 isolates were neutrophiles. Of these actinomycetes, 57.8, 32.5 and 50.4%, showed antagonistic activity against three rice pathogenic fungi; Fusarium moniliforme, Helminthosporium oryzae and Rhizoctonia solani, respectively. More than half of the isolates (68.1%) inhibited at least one tested pathogenic fungus, whereas 25.9% exhibited antifungal activities against all tested fungi. Three hundred and thirty-eight isolates (96.3%) produced siderophore and 266 isolates (75.8%) solubilized phosphate. A greater proportion of the acidophilic actinomycetes exhibited antifungal, siderophore production and phosphate solubilization activity compared with the neutrophiles. Three hundred and twenty-five isolates (92.6%) were classified as streptomycetes based on their morphological characteristics and the presence of the LL-isomeric form of diaminopimelic acid in whole-cell hydrolysates. The 16S ribosomal RNA (rRNA) gene analysis of representative non-streptomycete strains showed that the isolates belonged to seven genera, that is, Allokutzneria, Amycolatopsis, Mycobacterium, Nocardia, Nonomuraea, Saccharopolyspora and Verrucosispora. The potential antifungal acidophilic isolates, R9-4, R14-1, R14-5 and R20-5, showed close similarity to Streptomyces misionensis NBRC 13063(T) (AB184285) in terms of morphological characteristics and 16S rRNA gene sequences. PMID:25160509

  12. Jinggangmycin increases fecundity of the brown planthopper, Nilaparvata lugens (Stål) via fatty acid synthase gene expression.

    PubMed

    Li, Lei; Jiang, Yiping; Liu, Zongyu; You, Linlin; Wu, You; Xu, Bing; Ge, Linquan; Stanley, David; Song, Qisheng; Wu, Jincai

    2016-01-01

    The antibiotic jinggangmycin (JGM) is mainly used in controlling the rice sheath blight, Rhizoctonia solani, in China. JGM also enhances reproduction of the brown planthopper (BPH), Nilaparvata lugens (Stål). To date, however, molecular mechanisms of the enhancement are unclear. Our related report documented the influence of foliar JGM sprays on ovarian protein content. Here, we used isobaric tags for relative and absolute quantitation (iTRAQ) protocols to analyze ovarian proteins of BPH females following JGM spray (JGM-S) and topical application (JGM-T). We recorded changes in expression of 284 proteins (142? and 142?) in JGM-S compared to the JGM-S control group (S-control); 267 proteins were differentially expressed (130? and 137?) in JGM-T compared to the JGM-T control group (T-control), of which, 22 proteins were up-regulated in both groups. Comparing the JGM-S to the JGM-T group, 114 proteins were differentially expressed (62? and 52?). Based on the biological significance of fatty acids, pathway annotation and enrichment analysis, we designed a dsRNA construct to silence a gene encoding fatty acid synthase (FAS). FAS was more highly expressed in JGM-S vs S-control and JGM-S vs JGM-T groups. The dsFAS treatment reduced fecundity by about 46% and reduced ovarian and fat body fatty acid concentrations in JGM-S-treated females relative to controls. We infer FAS provides critically needed fatty acids to support JGM-enhanced fecundity in BPH. PMID:26388431

  13. Allelopathic effect of new introduced biofuel crops on the soil biota: A comparative study

    NASA Astrophysics Data System (ADS)

    Hed?nec, Petr; Frouz, Jan; Ustak, Sergej; Novotny, David

    2015-04-01

    Biofuel crops as an alternative to fossil fuels are a component of the energy mix in many countries. Many of them are introduced plants, so they pose a serious threat of biological invasions. Production of allelopathic compounds can increase invasion success by limiting co-occurring species in the invaded environment (novel weapons hypothesis). In this study, we focused on plant chemistry and production of allelopathic compounds by biofuel crops (hybrid sorrel Rumex tianschanicus x Rumex patientia and miscanthus Miscanthus sinensis) in comparison with invasive knotweed (Fallopia sachalinensis) and cultural meadow species. First, we tested the impact of leachates isolated from hybrid sorrel, miscanthus, knotweed and cultural meadow species compared to deionized water, used as a control, on seed germination of mustard (Sinapis arvensis) and wheat (Triticum aestivum) cultivated on sand and soil. Secondly, we studied the effect of leachates on the growth of soil fungal pathogens Fusarium culmorum, Rhizoctonia solani, Sclerotinia solani and Cochliobolus sativus. Finally, we tested the effect of litter of hybrid sorrel, miscanthus, knotweed and cultural meadow litter mixed with soil on population growth of Enchytraeus crypticus and Folsomia candida. Miscanthus and knotweed litter had a higher C:N ratio than the control meadow and hybrid sorrel litter. Miscanthus and hybrid sorrel litter had a higher content of phenols than knotweed and cultural meadow litter. Leachates from hybrid sorrel, miscanthus and knotweed biomass significantly decreased seed germination of wheat and mustard in both substrates. Soil fungal pathogens grew less vigorously on agar enriched by leachates from both biofuel crops than on agar enriched by knotweed and leachates. Litter from hybrid sorrel, miscanthus and knotweed significantly altered (both ways) the population growth of the soil mesofauna.

  14. The colonization patterns of different fungi on roots of Cymbidium hybridum plantlets and their respective inoculation effects on growth and nutrient uptake of orchid plantlets.

    PubMed

    Zhao, Xiao-Lan; Yang, Jing-Ze; Liu, Shu; Chen, Chun-Li; Zhu, Hai-Yan; Cao, Jun-Xi

    2014-07-01

    Cymbidium hybridum is one of the most popular pot orchids and cut flowers worldwide. However, the long vegetative growth period and the discordant blooming retarded its mass production. The mixotrophic nutritional mode of some chlorophyllous Cymbidium suggested the essential role of mycorrhizal fungi in the growth of adult green orchids. Here 34 root-associated endophytes were obtained from wild and cultivated Cymbidium and eight strains exhibited obvious growth-promoting effects on the C. hybridum plantlets with increasing root number, root diameter or new bud initiation. Among these, three isolates CL01, ZH3A-3 and CY5-1 with distinct cultural traits and colonization patterns showed better growth-promoting effects. Internal transcribed spacer sequence analyses and morphological observation revealed isolate CL01 belonged to Tulasnella-like Rhizoctonia, ZH3A-3, Umbelopsis nana and CY5-1, Scytalidium lignicola. Microscopic study showed isolate CL01 formed typical orchid mycorrhiza and isolate CY5-1 formed pseudo-mycorrhiza with orchid, whereas hyphae of isolate ZH3A-3 aggregated in the host velamen cells at regular intervals and caused the hypertrophied nucleus and aggregated cytoplasm of neighboring host cell. These three isolates significantly enhanced the increased percentage of total fresh weight of plantlets compared with un-inoculated control (83, 99 and 75%, respectively). In addition, isolate CL01 increased the N, P, Zn, Cu, Fe contents and ZH3A-3 significantly improved K, Ca, Cu, Mn contents of the symbiotic plantlets compared with control. These results suggested that the mass production of C. hybridum and related orchids could be improved by different beneficial fungi from its parents. PMID:24532077

  15. Predicting Cereal Root Disease in Western Australia Using Soil DNA and Environmental Parameters.

    PubMed

    Poole, Grant J; Harries, Martin; Hüberli, D; Miyan, S; MacLeod, W J; Lawes, Roger; McKay, A

    2015-08-01

    Root diseases have long been prevalent in Australian grain-growing regions, and most management decisions to reduce the risk of yield loss need to be implemented before the crop is sown. The levels of pathogens that cause the major root diseases can be measured using DNA-based services such as PreDicta B. Although these pathogens are often studied individually, in the field they often occur as mixed populations and their combined effect on crop production is likely to vary across diverse cropping environments. A 3-year survey was conducted covering most cropping regions in Western Australia, utilizing PreDicta B to determine soilborne pathogen levels and visual assessments to score root health and incidence of individual crop root diseases caused by the major root pathogens, including Rhizoctonia solani (anastomosis group [AG]-8), Gaeumannomyces graminis var. tritici (take-all), Fusarium pseudograminearum, and Pratylenchus spp. (root-lesion nematodes) on wheat roots for 115, 50, and 94 fields during 2010, 2011, and 2012, respectively. A predictive model was developed for root health utilizing autumn and summer rainfall and soil temperature parameters. The model showed that pathogen DNA explained 16, 5, and 2% of the variation in root health whereas environmental parameters explained 22, 11, and 1% of the variation in 2010, 2011, and 2012, respectively. Results showed that R. solani AG-8 soil pathogen DNA, environmental soil temperature, and rainfall parameters explained most of the variation in the root health. This research shows that interactions between environment and pathogen levels before seeding can be utilized in predictive models to improve assessment of risk from root diseases to assist growers to plan more profitable cropping programs. PMID:25822184

  16. Biosynthesis and characterization of zinc, magnesium and titanium nanoparticles: an eco-friendly approach

    NASA Astrophysics Data System (ADS)

    Raliya, Ramesh; Tarafdar, J. C.

    2014-02-01

    In the present study, zinc (Zn), magnesium (Mg) and titanium (Ti) nanoparticles synthesized using fungus by employing various precursor salts of sulfate salts, nitrate salts, chloride salts and oxide salts. To access the nanoparticle production potential, over a hundreds of fungi were isolated from the soil and tested with precursor salts of the Zn, Mg and Ti. Out of which, only 14 fungal isolates were identified, having potential to reduce metal salt into metal nanoparticles. Upon molecular identification, six were identified as Aspergillus flavus, two each as Aspergillus terreus and Aspergillus tubingensis and one each as Aspergillus niger, Rhizoctonia bataticola, Aspergillus fumigatus, and Aspergillus oryzae. Factors responsible for more production of monodispersed Zn, Mg and Ti nanoparticles were optimized. It was concluded that 0.01 mM precursor salt concentration, 72 h of incubation at pH 5.5 and temperature 28 °C resulted smaller nanoparticles obtained. The biosynthesized functional Zn and Ti nanoparticles can be stored up to 90 days and Mg nanoparticles up to 105 days in its nanoform. Bio-transformed products were analyzed using valid characterization technique i.e. dynamic light scattering, transmission electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy to confirm size, shape, surface morphology and elemental composition. It was found that the average size of developed nano Zn was 8.2 nm, with surface charge of -5.70 mV and 98 % particles were of Zn metal only. Similarly, the average size of Mg nanoparticles was 6.4 nm with surface charge of -6.66 and 97.4 % Mg metal yield, whereas, Ti nanoparticles size were found in the ranges between 1.5 and 30 nm with surface charge of -6.25 mV and 98.6 % Ti metal yield.

  17. Identifying glycoside hydrolase family 18 genes in the mycoparasitic fungal species Clonostachys rosea.

    PubMed

    Tzelepis, Georgios; Dubey, Mukesh; Jensen, Dan Funck; Karlsson, Magnus

    2015-07-01

    Clonostachysrosea is a mycoparasitic fungal species that is an efficient biocontrol agent against many plant diseases. During mycoparasitic interactions, one of the most crucial steps is the hydrolysis of the prey's fungal cell wall, which mainly consists of glucans, glycoproteins and chitin. Chitinases are hydrolytic enzymes responsible for chitin degradation and it is suggested that they play an important role in fungal-fungal interactions. Fungal chitinases belong exclusively to the glycoside hydrolase (GH) family 18.These GH18 proteins are categorized into three distinct phylogenetic groups (A, B and C), subdivided into several subgroups. In this study, we identified 14 GH18 genes in the C. rosea genome, which is remarkably low compared with the high numbers found in mycoparasitic Trichoderma species. Phylogenetic analysis revealed that C. rosea contains eight genes in group A, two genes in group B, two genes in group C, one gene encoding a putative ENGase (endo-?-N-acetylglucosaminidase) and the ech37 gene, which is of bacterial origin. Gene expression analysis showed that only two genes had higher transcription levels during fungal-fungal interactions, while eight out of 14 GH18 genes were triggered by chitin. Furthermore, deletion of the C group chiC2 gene decreased the growth inhibitory activity of C. rosea culture filtrates against Botrytis cinerea and Rhizoctonia solani, although the biocontrol ability of C. rosea against B. cinerea was not affected. In addition, a potential role of the CHIC2 chitinase in the sporulation process was revealed. These results provide new information about the role of GH18 proteins in mycoparasitic interactions. PMID:25881898

  18. Bioactivities by a crude extract from the Greenlandic Pseudomonas sp. In5 involves the nonribosomal peptides, nunamycin and nunapeptin

    PubMed Central

    Venditto, Vincent J.; Hennessy, Rosanna C.

    2015-01-01

    Background. Bioactive microbial metabolites provide a successful source of novel compounds with pharmaceutical potentials. The bacterium Pseudomonas sp. In5 is a biocontrol strain isolated from a plant disease suppressive soil in Greenland, which produces two antimicrobial nonribosomal peptides (NRPs), nunapeptin and nunamycin. Methods. In this study, we used in vitro antimicrobial and anticancer bioassays to evaluate the potential bioactivities of both a crude extract derived from Pseudomonas sp. In5 and NRPs purified from the crude extract. Results. We verified that the crude extract derived from Pseudomonas sp. In5 showed suppressive activity against the basidiomycete Rhizoctonia solani by inducing a mitochondrial stress-response. Furthermore, we confirmed suppressive activity against the oomycete Pythium aphanidermatum by the Pseudomonas sp. In5 crude extract, and that the purified nunamycin and nunapeptin displayed distinct antimicrobial activities. In addition to the antimicrobial activity, we found that treatment of the cancer cell lines, Jurkat T-cells, Granta cells, and melanoma cells, with the Pseudomonas sp. In5 crude extract increased staining with the apoptotic marker Annexin V while no staining of healthy normal cells, i.e., naïve or activated CD4 T-cells, was observed. Treatment with either of the NRPs alone did not increase Annexin V staining of the Jurkat T-cells, despite individually showing robust antimicrobial activity, whereas an anticancer activity was detected when nunamycin and nunapeptin were used in combination. Discussion. Our results suggest that the bioactivity of a crude extract derived from Pseudomonas sp. In5 involves the presence of both nunamycin and nunapeptin and highlight the possibility of synergy between multiple microbial metabolites.

  19. Transcriptomic response of the mycoparasitic fungus Trichoderma atroviride to the presence of a fungal prey

    SciTech Connect

    Seidl, Verena; Song, Lifu; Lindquist, Erika; Gruber, Sabine; Koptchinskiy, Alexeji; Zeilinger, Susanne; Schmoll, Monika; Martinez, Pedro; Sun, Jibin; Grigoriev, Igor V.; Herrera-Estrella, Alfredo; Baker, Scott E.; Kubicek, Christian P.

    2009-11-30

    Background: Fungi of the genus Trichoderma are effective mycoparasites an for this reason used as biocontrol agents agents plant pathogenic fungi. The ability to recognize, combat and finally besiege and kill the prey are essential skills for this process. Only fragments of the biochemical processes related to this ability have been uncovered so far, however. This study aims at uncovering transcriptional responses occurring in the mycoparasite Trichoderma atroviride when being confronted with a potential prey. Results: T. atroviride was confronted with two fungal preys, Botrytis cinerea and Rhizoctonia solani, and cDNAs prepared from mycelia immediately before getting into physical contact with them (“onset of mycoparasitism”), and compared with such prepared from mycelial and conidiating cultures, respectively. About 3000 ESTs, representing about 900 genes each, were obtained from each of these three conditions. 65 genes, represented by 439 ESTs, were specifically and significantly overexpressed during onset of mycoparasitism, and the expression of a subset thereof verified by expression analysis. They comprised 18 KOG groups, but were most abundant from those including posttranslational processing (159 from 183 ESTs), and amino acid metabolism (70 of 84 ESTs), respectively. Several heat shock factors and tRNA synthases were particularly abundant. Metabolic network analysis confirmed the upregulation of the amino acid biosynthesic and the lipid catabolic capacity. Conclusion: Analysis of the genes overexpressed during the onset of mycoparasitism in T. atroviride has revealed that the fungus reacts to this condition with several previously undetected physiological reactions including strong stress response, sensing of nitrogen shortage and lipid catabolism. The data enable a new and more comprehensive interpretation of the physiology of mycoparasitism, and will aid in the selection of traits for breeding of biocontrol strains by recombinant techniques.

  20. Gene expression in mycorrhizal orchid protocorms suggests a friendly plant-fungus relationship.

    PubMed

    Perotto, Silvia; Rodda, Marco; Benetti, Alex; Sillo, Fabiano; Ercole, Enrico; Rodda, Michele; Girlanda, Mariangela; Murat, Claude; Balestrini, Raffaella

    2014-06-01

    Orchids fully depend on symbiotic interactions with specific soil fungi for seed germination and early development. Germinated seeds give rise to a protocorm, a heterotrophic organ that acquires nutrients, including organic carbon, from the mycorrhizal partner. It has long been debated if this interaction is mutualistic or antagonistic. To investigate the molecular bases of the orchid response to mycorrhizal invasion, we developed a symbiotic in vitro system between Serapias vomeracea, a Mediterranean green meadow orchid, and the rhizoctonia-like fungus Tulasnella calospora. 454 pyrosequencing was used to generate an inventory of plant and fungal genes expressed in mycorrhizal protocorms, and plant genes could be reliably identified with a customized bioinformatic pipeline. A small panel of plant genes was selected and expression was assessed by real-time quantitative PCR in mycorrhizal and non-mycorrhizal protocorm tissues. Among these genes were some markers of mutualistic (e.g. nodulins) as well as antagonistic (e.g. pathogenesis-related and wound/stress-induced) genes. None of the pathogenesis or wound/stress-related genes were significantly up-regulated in mycorrhizal tissues, suggesting that fungal colonization does not trigger strong plant defence responses. In addition, the highest expression fold change in mycorrhizal tissues was found for a nodulin-like gene similar to the plastocyanin domain-containing ENOD55. Another nodulin-like gene significantly more expressed in the symbiotic tissues of mycorrhizal protocorms was similar to a sugar transporter of the SWEET family. Two genes coding for mannose-binding lectins were significantly up-regulated in the presence of the mycorrhizal fungus, but their role in the symbiosis is unclear. PMID:24760407

  1. Characterization of a Pathogen Induced Thaumatin-Like Protein Gene AdTLP from Arachis diogoi, a Wild Peanut

    PubMed Central

    Singh, Naveen Kumar; Kumar, Koppolu Raja Rajesh; Kumar, Dilip; Shukla, Pawan; Kirti, P. B.

    2013-01-01

    Peanut (Arachis hypogaea L) is one of the widely cultivated and leading oilseed crops of the world and its yields are greatly affected by various biotic and abiotic stresses. Arachis diogoi, a wild relative of peanut, is an important source of genes for resistance against various stresses that affect peanut. In our previous study a thaumatin-like protein gene was found to be upregulated in a differential expression reverse transcription PCR (DDRT-PCR) study using the conidial spray of the late leaf spot pathogen, Phaeoisariopsis personata. In the present study, the corresponding full length cDNA was cloned using RACE-PCR and has been designated as AdTLP. It carried an open reading frame of 726 bp potentially capable of encoding a polypeptide of 241 amino acids with 16 conserved cysteine residues. The semi-quantitative RT-PCR analysis showed that the transcript level of AdTLP increased upon treatment with the late leaf spot pathogen of peanut, P. personata and various hormone treatments indicating its involvement in both, biotic and abiotic stresses. The antifungal activity of the purified recombinant protein was checked against different fungal pathogens, which showed enhanced anti-fungal activity compared to many other reported TLP proteins. The recombinant AdTLP-GFP fusion protein was found to be predominantly localized to extracellular spaces. Transgenic tobacco plants ectopically expressing AdTLP showed enhanced resistance to fungal pathogen, Rhizoctonia solani. The seedling assays showed enhanced tolerance of AdTLP transgenic plants against salt and oxidative stress. The transcript analysis of various defense related genes highlighted constitutively higher level expression of PR1a, PI-I and PI-II genes in transgenic plants. These results suggest that the AdTLP is a good candidate gene for enhancing stress resistance in crop plants. PMID:24367621

  2. Exploring the Antibacterial and Antifungal Potential of Jellyfish-Associated Marine Fungi by Cultivation-Dependent Approaches

    PubMed Central

    Yue, Yang; Yu, Huahua; Li, Rongfeng; Xing, Ronge; Liu, Song; Li, Pengcheng

    2015-01-01

    Fungi isolated from marine invertebrates are of considerable importance as new promising sources of unique secondary metabolites with significant biomedical potential. However, the cultivable fungal community harbored in jellyfish was less investigated. In this work, we seek to recover symbiotic fungi from different tissues of jellyfish Nemopilema nomurai. A total of seven morphotypes were isolated, which were assigned into four genera (Aspergillus, Cladosporium, Purpureocillium, and Tilletiopsis) from two phyla (Ascomycota and Basidiomycota) by comparing the rDNA-ITS sequences with the reference sequences in GenBank. The most fungi were found in the inner tissues of subumbrella. Two of the cultivation-independent procedures, changing media type and co-cultivation, were employed to maximize the complexity of metabolites. Thus, thirteen EtOAc gum were obtained and fingerprinted by High Performance Liquid Chromatography (HPLC) equipped with a photodiode array (PDA) detector. Antibacterial and antifungal activities of these complex mixtures were tested against a panel of bacterial and fungal pathogens. The antimicrobial results showed that all of the 13 EtOAc extracts displayed different levels of antibacterial activity, three of which exhibited strong to significant antibacterial activity to the bacterial pathogens Staphylococcus aureus and Salmonella entrica. Antifungal activity indicated that the EtOAc extracts from pure culture of Aspergillus versicolor and co-culture of A. versicolor and Tilletiopsis sp. in rice media were promising for searching new compounds, with the maximal mycelial growth inhibition of 82.32% ± 0.61% for Rhizoctonia solani and 48.41% ± 11.02% for Botrytis cinerea at 200 ?g/ml, respectively. This study is the first report on the antibacterial and antifungal activity of jellyfish-associated fungi and allows the first sight into cultivable fungal community residing in jellyfish. Induced metabolites by cultivation-dependent approaches provides a new reservoir for drug discovery from jellyfish-derived fungi. PMID:26637162

  3. Effect of abiotic stress on phosphate solubilization by biocontrol fungus Trichoderma sp.

    PubMed

    Rawat, Rekha; Tewari, Lakshmi

    2011-05-01

    This study was undertaken to explore the role of Trichoderma sp. in phosphate (P) solubilization and antagonism against fungal phytopathogens. All fungal isolates (SE(6), KT(6), KT(28), and BRT(11)) and a standard culture of T. harzianum (Th-std) were able to antagonize two fungal phytopathogens (Sclerotium rolfsii and Rhizoctonia solani) of chickpea (Cicer arietinum L.) wilt complex. Transmission electron microscopic studies (TEM) further confirmed ultra-cytological changes in the sclerotia of S. rolfsii parasitized by Trichoderma sp. All fungal cultures exhibited production of NH(3) and siderophore, but only BRT(11), SE(6), and Th-std could produce HCN. Among all the cultures tested, isolate KT(6) was found to be most effective for solubilization of ferric phosphate releasing 398.4 ?g ml(-1) phosphate while isolates BRT(11) and SE(6) showed more potential for tricalcium phosphate (TCP) solubilization releasing 449.05 and 412.64 ?g ml(-1) phosphate, respectively, in their culture filtrates. Part of this study focused on the influence of abiotic stress conditions such as pH, temperature, and heavy metal (cadmium) on phosphate (TCP) solubilizing efficiency. Two selected cultures KT(6) and T. harzianum retained their P solubilizing potential at varying concentrations of cadmium (0-1000 ?g ml(-1)). Isolate KT(6) and standard culture of T. harzianum released 278.4 and 287.6 ?g ml(-1) phosphate, respectively, at 1000 ?g ml(-1)cadmium. Maximum solubilization of TCP was obtained at alkaline pH and at 28°C temperature. Isolate BRT(11) was found most alkalo-tolerant releasing 448.0 ?g ml(-1) phosphate at pH 9. PMID:21327557

  4. Isolation and Identification of Antifungal Compounds from Bacillus subtilis C9 Inhibiting the Growth of Plant Pathogenic Fungi

    PubMed Central

    Islam, Md. Rezuanul; Jeong, Yong Tae; Lee, Yong Se

    2012-01-01

    Antagonistic microorganisms against Rhizoctonia solani were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by R. solani AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as Bacillus subtilis subsp. subtilis. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance (1H NMR), carbon nuclear magneric resonance (13C NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants. PMID:22783136

  5. An Arabidopsis mutant impaired in intracellular calcium elevation is sensitive to biotic and abiotic stress

    PubMed Central

    2014-01-01

    Background Ca2+, a versatile intracellular second messenger in various signaling pathways, initiates many responses involved in growth, defense and tolerance to biotic and abiotic stress. Endogenous and exogenous signals induce cytoplasmic Ca2+ ([Ca2+]cyt) elevation, which are responsible for the appropriate downstream responses. Results Here we report on an ethyl-methane sulfonate-mediated Arabidopsis mutant that fails to induce [Ca2+]cyt elevation in response to exudate preparations from the pathogenic mibrobes Alternaria brassicae, Rhizoctonia solani, Phytophthora parasitica var. nicotianae and Agrobacterium tumefaciens. The cytoplasmic Ca2+elevation mutant1 (cycam1) is susceptible to infections by A. brassicae, its toxin preparation and sensitive to abiotic stress such as drought and salt. It accumulates high levels of reactive oxygen species and contains elevated salicylic acid, abscisic acid and bioactive jasmonic acid iso-leucine levels. Reactive oxygen species- and phytohormone-related genes are higher in A. brassicae-treated wild-type and mutant seedlings. Depending on the analysed response, the elevated levels of defense-related compounds are either caused by the cycam mutation and are promoted by the pathogen, or they are mainly due to the pathogen infection or application of pathogen-associated molecular patterns. Furthermore, cycam1 shows altered responses to abscisic acid treatments: the hormone inhibits germination and growth of the mutant. Conclusions We isolated an Arabidopsis mutant which fails to induce [Ca2+]cyt elevation in response to exudate preparations from various microbes. The higher susceptibility of the mutant to pathogen infections correlates with the higher accumulation of defense-related compounds, such as phytohormones, reactive oxygen-species, defense-related mRNA levels and secondary metabolites. Therefore, CYCAM1 couples [Ca2+]cyt elevation to biotic, abiotic and oxidative stress responses. PMID:24920452

  6. Expression of BvGLP-1 encoding a germin-like protein from sugar beet in Arabidopsis thaliana leads to resistance against phytopathogenic fungi.

    PubMed

    Knecht, Katrin; Seyffarth, Monique; Desel, Christine; Thurau, Tim; Sherameti, Irena; Lou, Binggan; Oelmüller, Ralf; Cai, Daguang

    2010-04-01

    Nematode (Heterodera schachtii) resistance in sugar beet (Beta vulgaris) is controlled by a single dominant resistance gene, Hs1(pro-1). BvGLP-1 was cloned from resistant sugar beet. The BvGLP-1 messenger (m)RNA is highly upregulated in the resistant plants after nematode infection, suggesting its role in the Hs1(pro-1) mediated resistance. BvGLP-1 exhibits sequence homology to a set of plant germin-like proteins (GLP), from which several have proved to be functional in plant basal or defense resistance against fungal pathogens. To test whether BvGLP-1 is also involved in the plant-fungus interaction, we transferred BvGLP-1 into Arabidopsis and challenged the transgenic plants with the pathogenic fungi Verticillium longisporum and Rhizoctonia solani as well as with the beneficial endophytic fungus Piriformospora indica. The expression of BvGLP-1 in Arabidopsis elevated the H(2)O(2) content and conferred significant resistance to V. longisporum and R. solani but did not affect the beneficial interaction with P. indica in seedlings. Microscopic observations revealed a dramatic reduction in the amount of hyphae of the pathogenic fungi on the root surface as well as of fungal mycelium developed inside the roots of transgenic Arabidopsis compared with wild-type plants. Molecular analysis demonstrated that the BvGLP-1 expression in Arabidopsis constitutively activates the expression of a subset of plant defense-related proteins such as PR-1 to PR-4 and PDF1.2 but not PDF2.1 and PDF2.3. In contrast, the PDF2.1 mRNA level was downregulated. These data suggest an important role of BvGLP-1 in establishment of plant defense responses, which follow specific signaling routes that diverge from those induced by the beneficial fungus. PMID:20192832

  7. Tandem combination of Trigonella foenum-graecum defensin (Tfgd2) and Raphanus sativus antifungal protein (RsAFP2) generates a more potent antifungal protein.

    PubMed

    Karri, Vasavirama; Bharadwaja, Kirti Pulugurtha

    2013-11-01

    Plant defensins are small (45 to 54 amino acids) positively charged antimicrobial peptides produced by the plant species, which can inhibit the growth of a broad range of fungi at micro-molar concentrations. These basic peptides share a common characteristic three-dimensional folding pattern with one ?-helix and three ?-sheets that are stabilized by eight disulfide-linked cysteine residues. Instead of using two single-gene constructs, it is beneficial when two effective genes are made into a single fusion gene with one promoter and terminator. In this approach, we have linked two plant defensins namely Trigonella foenum-graecum defensin 2 (Tfgd2) and Raphanus sativus antifungal protein 2 (RsAFP2) genes by a linker peptide sequence (occurring in the seeds of Impatiens balsamina) and made into a single-fusion gene construct. We used pET-32a+ vector system to express Tfgd2-RsAFP2 fusion gene with hexahistidine tag in Escherichia coli BL21 (DE3) pLysS cells. Induction of these cells with 1 mM IPTG achieved expression of the fusion protein. The solubilized His6-tagged recombinant fusion protein was purified by immobilized-metal (Ni2+) affinity column chromatography. The final yield of the fusion protein was 500 ng/?L. This method produced biologically active recombinant His6-tagged fusion protein, which exhibited potent antifungal action towards the plant pathogenic fungi (Botrytis cinerea, Fusarium moniliforme, Fusarium oxysporum, Phaeoisariopsis personata and Rhizoctonia solani along with an oomycete pathogen Phytophthora parasitica var nicotianae) at lower concentrations under in vitro conditions. This strategy of combining activity of two defensin genes into a single-fusion gene will definitely be a promising utility for biotechnological applications. PMID:24022215

  8. Posttranscriptional Regulation of 2,4-Diacetylphloroglucinol Production by GidA and TrmE in Pseudomonas fluorescens 2P24

    PubMed Central

    Zhang, Wei; Zhao, Zhao; Zhang, Bo; Wu, Xiao-Gang; Ren, Zheng-Guang

    2014-01-01

    Pseudomonas fluorescens 2P24 is a soilborne bacterium that synthesizes and excretes multiple antimicrobial metabolites. The polyketide compound 2,4-diacetylphloroglucinol (2,4-DAPG), synthesized by the phlACBD locus, is its major biocontrol determinant. This study investigated two mutants defective in antagonistic activity against Rhizoctonia solani. Deletion of the gidA (PM701) or trmE (PM702) gene from strain 2P24 completely inhibited the production of 2,4-DAPG and its precursors, monoacetylphloroglucinol (MAPG) and phloroglucinol (PG). The transcription of the phlA gene was not affected, but the translation of the phlA and phlD genes was reduced significantly. Two components of the Gac/Rsm pathway, RsmA and RsmE, were found to be regulated by gidA and trmE, whereas the other components, RsmX, RsmY, and RsmZ, were not. The regulation of 2,4-DAPG production by gidA and trmE, however, was independent of the Gac/Rsm pathway. Both the gidA and trmE mutants were unable to produce PG but could convert PG to MAPG and MAPG to 2,4-DAPG. Overexpression of PhlD in the gidA and trmE mutants could restore the production of PG and 2,4-DAPG. Taken together, these findings suggest that GidA and TrmE are positive regulatory elements that influence the biosynthesis of 2,4-DAPG posttranscriptionally. PMID:24747907

  9. Effect of the strain Bacillus amyloliquefaciens FZB42 on the microbial community in the rhizosphere of lettuce under field conditions analyzed by whole metagenome sequencing

    PubMed Central

    Kröber, Magdalena; Wibberg, Daniel; Grosch, Rita; Eikmeyer, Felix; Verwaaijen, Bart; Chowdhury, Soumitra P.; Hartmann, Anton; Pühler, Alfred; Schlüter, Andreas

    2014-01-01

    Application of the plant associated bacterium Bacillus amyloliquefaciens FZB42 on lettuce (Lactuca sativa) confirmed its capability to promote plant growth and health by reducing disease severity (DS) caused by the phytopathogenic fungus Rhizoctonia solani. Therefore this strain is commercially applied as an eco-friendly plant protective agent. It is able to produce cyclic lipopeptides (CLP) and polyketides featuring antifungal and antibacterial properties. Production of these secondary metabolites led to the question of a possible impact of strain FZB42 on the composition of microbial rhizosphere communities after its application. Rating of DS and lettuce growth during a field trial confirmed the positive impact of strain FZB42 on the health of the host plant. To verify B. amyloliquefaciens as an environmentally compatible plant protective agent, its effect on the indigenous rhizosphere community was analyzed by metagenome sequencing. Rhizosphere microbial communities of lettuce treated with B. amyloliquefaciens FZB42 and non-treated plants were profiled by high-throughput metagenome sequencing of whole community DNA. Fragment recruitments of metagenome sequence reads on the genome sequence of B. amyloliquefaciens FZB42 proved the presence of the strain in the rhizosphere over 5 weeks of the field trial. Comparison of taxonomic community profiles only revealed marginal changes after application of strain FZB42. The orders Burkholderiales, Actinomycetales and Rhizobiales were most abundant in all samples. Depending on plant age a general shift within the composition of the microbial communities that was independent of the application of strain FZB42 was observed. In addition to the taxonomic profiling, functional analysis of annotated sequences revealed no major differences between samples regarding application of the inoculant strain. PMID:24904564

  10. Comparative transcriptomics reveals different strategies of Trichoderma mycoparasitism

    PubMed Central

    2013-01-01

    Background Trichoderma is a genus of mycotrophic filamentous fungi (teleomorph Hypocrea) which possess a bright variety of biotrophic and saprotrophic lifestyles. The ability to parasitize and/or kill other fungi (mycoparasitism) is used in plant protection against soil-borne fungal diseases (biological control, or biocontrol). To investigate mechanisms of mycoparasitism, we compared the transcriptional responses of cosmopolitan opportunistic species and powerful biocontrol agents Trichoderma atroviride and T. virens with tropical ecologically restricted species T. reesei during confrontations with a plant pathogenic fungus Rhizoctonia solani. Results The three Trichoderma spp. exhibited a strikingly different transcriptomic response already before physical contact with alien hyphae. T. atroviride expressed an array of genes involved in production of secondary metabolites, GH16 ß-glucanases, various proteases and small secreted cysteine rich proteins. T. virens, on the other hand, expressed mainly the genes for biosynthesis of gliotoxin, respective precursors and also glutathione, which is necessary for gliotoxin biosynthesis. In contrast, T. reesei increased the expression of genes encoding cellulases and hemicellulases, and of the genes involved in solute transport. The majority of differentially regulated genes were orthologues present in all three species or both in T. atroviride and T. virens, indicating that the regulation of expression of these genes is different in the three Trichoderma spp. The genes expressed in all three fungi exhibited a nonrandom genomic distribution, indicating a possibility for their regulation via chromatin modification. Conclusion This genome-wide expression study demonstrates that the initial Trichoderma mycotrophy has differentiated into several alternative ecological strategies ranging from parasitism to predation and saprotrophy. It provides first insights into the mechanisms of interactions between Trichoderma and other fungi that may be exploited for further development of biofungicides. PMID:23432824

  11. Transcriptomic response of the mycoparasitic fungus Trichoderma atroviride to the presence of a fungal prey

    SciTech Connect

    Seidl, Verena; Song, Lifu; Lindquist, Erika; Gruber, Sabine; Koptchinskiy, Alexeji; Zeilinger, Susanne; Schmoll, Monika; Martinez, Pedro; Sun, Jibin; Grigoriev, Igor; Herrera-Estrella, Alfredo; Baker, Scott E; Kubicek, Christian P.

    2010-07-23

    BACKGROUND: Combating the action of plant pathogenic microorganisms by mycoparasitic fungi has been announced as an attractive biological alternative to the use of chemical fungicides since two decades. The fungal genus Trichoderma includes a high number of taxa which are able to recognize, combat and finally besiege and kill their prey. Only fragments of the biochemical processes related to this ability have been uncovered so far, however. RESULTS: We analyzed genome-wide gene expression changes during the begin of physical contact between Trichoderma atroviride and two plant pathogens Botrytis cinerea and Rhizoctonia solani, and compared with gene expression patterns of mycelial and conidiating cultures, respectively. About 3000 ESTs, representing about 900 genes, were obtained from each of these three growth conditions. 66 genes, represented by 442 ESTs, were specifically and significantly overexpressed during onset of mycoparasitism, and the expression of a subset thereof was verified by expression analysis. The upregulated genes comprised 18 KOG groups, but were most abundant from the groups representing posttranslational processing, and amino acid metabolism, and included components of the stress response, reaction to nitrogen shortage, signal transduction and lipid catabolism. Metabolic network analysis confirmed the upregulation of the genes for amino acid biosynthesis and of those involved in the catabolism of lipids and aminosugars. CONCLUSION: The analysis of the genes overexpressed during the onset of mycoparasitism in T. atroviride has revealed that the fungus reacts to this condition with several previously undetected physiological reactions. These data enable a new and more comprehensive interpretation of the physiology of mycoparasitism, and will aid in the selection of traits for improvement of biocontrol strains by recombinant techniques.

  12. Role of gliotoxin in the symbiotic and pathogenic interactions of Trichoderma virens.

    PubMed

    Vargas, Walter A; Mukherjee, Prasun K; Laughlin, David; Wiest, Aric; Moran-Diez, Maria E; Kenerley, Charles M

    2014-10-01

    Using a gene disruption strategy, we generated mutants in the gliP locus of the plant-beneficial fungus Trichoderma virens that were no longer capable of producing gliotoxin. Phenotypic assays demonstrated that the gliP-disrupted mutants grew faster, were more sensitive to oxidative stress and exhibited a sparse colony edge compared with the WT strain. In a plate confrontation assay, the mutants deficient in gliotoxin production were ineffective as mycoparasites against the oomycete, Pythium ultimum, and the necrotrophic fungal pathogen, Sclerotinia sclerotiorum, but retained mycoparasitic ability against Rhizoctonia solani. Biocontrol assays in soil showed that the mutants were incapable of protecting cotton seedlings from attack by P. ultimum, against which the WT strain was highly effective. The mutants, however, were as effective as the WT strain in protecting cotton seedlings against R. solani. Loss of gliotoxin production also resulted in a reduced ability of the mutants to attack the sclerotia of S. sclerotiorum compared with the WT. The addition of exogenous gliotoxin to the sclerotia colonized by the mutants partially restored their degradative abilities. Interestingly, as in Aspergillus fumigatus, an opportunistic human pathogen, gliotoxin was found to be involved in pathogenicity of T. virens against larvae of the wax moth, Galleria mellonella. The loss of gliotoxin production in T. virens was restored by complementation with the gliP gene from A. fumigatus. We have, thus, demonstrated that the putative gliP cluster of T. virens is responsible for the biosynthesis of gliotoxin, and gliotoxin is involved in mycoparasitism and biocontrol properties of this plant-beneficial fungus. PMID:25082950

  13. Stress-Responsive Expression, Subcellular Localization and Protein–Protein Interactions of the Rice Metacaspase Family

    PubMed Central

    Huang, Lei; Zhang, Huijuan; Hong, Yongbo; Liu, Shixia; Li, Dayong; Song, Fengming

    2015-01-01

    Metacaspases, a class of cysteine-dependent proteases like caspases in animals, are important regulators of programmed cell death (PCD) during development and stress responses in plants. The present study was focused on comprehensive analyses of expression patterns of the rice metacaspase (OsMC) genes in response to abiotic and biotic stresses and stress-related hormones. Results indicate that members of the OsMC family displayed differential expression patterns in response to abiotic (e.g., drought, salt, cold, and heat) and biotic (e.g., infection by Magnaporthe oryzae, Xanthomonas oryzae pv. oryzae and Rhizoctonia solani) stresses and stress-related hormones such as abscisic acid, salicylic acid, jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (a precursor of ethylene), although the responsiveness to these stresses or hormones varies to some extent. Subcellular localization analyses revealed that OsMC1 was solely localized and OsMC2 was mainly localized in the nucleus. Whereas OsMC3, OsMC4, and OsMC7 were evenly distributed in the cells, OsMC5, OsMC6, and OsMC8 were localized in cytoplasm. OsMC1 interacted with OsLSD1 and OsLSD3 while OsMC3 only interacted with OsLSD1 and that the zinc finger domain in OsMC1 is responsible for the interaction activity. The systematic expression and biochemical analyses of the OsMC family provide valuable information for further functional studies on the biological roles of OsMCs in PCD that is related to abiotic and biotic stress responses. PMID:26193260

  14. Characterization of an Endophytic Gloeosporium sp. and Its Novel Bioactivity with "Synergistans".

    PubMed

    Schaible, George A; Strobel, Gary A; Mends, Morgan Tess; Geary, Brad; Sears, Joe

    2015-07-01

    Gloeosporium sp. (OR-10) was isolated as an endophyte of Tsuga heterophylla (Western hemlock). Both ITS and 18S sequence analyses indicated that the organism best fits either Hypocrea spp. or Trichoderma spp., but neither of these organisms possess conidiophores associated with acervuli, in which case the endophytic isolate OR-10 does. Therefore, the preferred taxonomic assignment was primarily based on the morphological features of the organism as one belonging to the genus Gloeosporium sp. These taxonomic observations clearly point out that limited ITS and 18S sequence information can be misleading when solely used in making taxonomic assignments. The volatile phase of this endophyte was active against a number of plant pathogenic fungi including Phytophthora palmivora, Rhizoctonia solani, Ceratocystis ulmi, Botrytis cinerea, and Verticillium dahliae. Among several terpenes and furans, the most abundantly produced compound in the volatile phase was 6-pentyl-2H-pyran-2-one, a compound possessing antimicrobial activities. When used in conjunction with microliter amounts of any in a series of esters or isobutyric acid, an enhanced inhibitory response occurred with each test fungus that was greater than that exhibited by Gloeosporium sp. or the compounds tested individually. Compounds behaving in this manner are hereby designated "synergistans." An expression of the "median synergistic effect," under prescribed conditions, has been termed the mSE50. This value describes the amount of a potential synergistan that is required to yield an additional median 50% inhibition of a target organism. In this report, the mSE50s are reported for a series of esters and isobutyric acid. The results indicated that isoamyl acetate, allyl acetate, and isobutyric acid generally possessed the lowest mSE50 values. The value and potential importance of these microbial synergistic effects to the microbial environment are also discussed. PMID:25501886

  15. The importance of chorismate mutase in the biocontrol potential of Trichoderma parareesei

    PubMed Central

    Pérez, Esclaudys; Rubio, M. Belén; Cardoza, Rosa E.; Gutiérrez, Santiago; Bettiol, Wagner; Monte, Enrique; Hermosa, Rosa

    2015-01-01

    Species of Trichoderma exert direct biocontrol activity against soil-borne plant pathogens due to their ability to compete for nutrients and to inhibit or kill their targets through the production of antibiotics and/or hydrolytic enzymes. In addition to these abilities, Trichoderma spp. have beneficial effects for plants, including the stimulation of defenses and the promotion of growth. Here we study the role in biocontrol of the T. parareesei Tparo7 gene, encoding a chorismate mutase (CM), a shikimate pathway branch point leading to the production of aromatic amino acids, which are not only essential components of protein synthesis but also the precursors of a wide range of secondary metabolites. We isolated T. parareesei transformants with the Tparo7 gene silenced. Compared with the wild-type, decreased levels of Tparo7 expression in the silenced transformants were accompanied by reduced CM activity, lower growth rates on different culture media, and reduced mycoparasitic behavior against the phytopathogenic fungi Rhizoctonia solani, Fusarium oxysporum and Botrytis cinerea in dual cultures. By contrast, higher amounts of the aromatic metabolites tyrosol, 2-phenylethanol and salicylic acid were detected in supernatants from the silenced transformants, which were able to inhibit the growth of F. oxysporum and B. cinerea. In in vitro plant assays, Tparo7-silenced transformants also showed a reduced capacity to colonize tomato roots. The effect of Tparo7-silencing on tomato plant responses was examined in greenhouse assays. The growth of plants colonized by the silenced transformants was reduced and the plants exhibited an increased susceptibility to B. cinerea in comparison with the responses observed for control plants. In addition, the plants turned yellowish and were defective in jasmonic acid- and ethylene-regulated signaling pathways which was seen by expression analysis of lipoxygenase 1 (LOX1), ethylene-insensitive protein 2 (EIN2) and pathogenesis-related protein 1 (PR-1) genes. PMID:26579090

  16. Phoenix dactylifera (date palm) pit aqueous extract mediated novel route for synthesis high stable silver nanoparticles with high antifungal and antibacterial activity.

    PubMed

    Khatami, Mehrdad; Pourseyedi, Shahram

    2015-08-01

    The biological synthesis of silver nanoparticles (AgNPs) was conducted using date palm pit aqueous extract. The first visible sign of the synthesis of AgNPs was the change in colour of reaction mixtures from yellowish to reddish brown. The resulting synthesised AgNPs were characterised using UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The UV-visible spectra gave surface plasmon resonance at 428 nm. XRD confirmed that the silver particles formed in our experiments were in the form of nanocrystals. TEM images revealed the formation of AgNPs with spherical shape and sizes in the range between 1-40 nm. DLS showed nanoparticles with an average size of 27 nm. Fourier transform infrared spectroscopy indicated the role of different possible functional groups (carboxyl, amine, aromatic and hydroxyl) in the formation of AgNPs. AgNPs were stable at 28°C in vitro for over a year without any precipitation or decreased production of antimicrobial effect. Then, the antifungal and antibacterial activities of synthesised AgNPs were investigated. The synthesised AgNPs showed significant inhibitory effects on Rhizoctonia solani (AG2_2) cultures, so that the concentration of 25 µg/ml prevented approximately 83% of the mycelium growth of the fungus. Then, the broth macro-dilution method was used for examining antibacterial effect of AgNPs. The minimum inhibitory concentration and minimum bactericide concentration against Klebsiella pneumonia (PCI 602) and Acinetobacter baumannii (ATCC 19606) were recorded as 1.56 and 3.12 µg/ml AgNPs, respectively. PMID:26224347

  17. Soil Type Dependent Rhizosphere Competence and Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Lettuce

    PubMed Central

    Schreiter, Susanne; Sandmann, Martin; Smalla, Kornelia; Grosch, Rita

    2014-01-01

    Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 106 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected the bottom rot disease severity. PMID:25099168

  18. Efficacy of Oryza sativa husk and Quercus phillyraeoides extracts for the in vitro and in vivo control of fungal rot disease of white yam (Dioscorea rotundata Poir).

    PubMed

    Dania, Victor Ohileobo; Fadina, Olubunmi Omowunmi; Ayodele, Maria; Kumar, P Lava

    2014-01-01

    Tuber rot disease is a major constraint to white yam (Dioscorea rotundata) production, accounting for 50-60% of annual yield losses in Nigeria. The main method of control using synthetic fungicides is being discouraged due to human and environmental health hazards. The potential of Oryza sativa husk (OSH) and Quercus phillyraeoides (QP) extracts for the in vitro and in vivo control of six virulent rot-causing fungal pathogens, Lasiodiplodia theobromae, Aspergillus niger, Rhizoctonia solani, Penicillium oxalicum, Sclerotium rolfsii, and Fusarium oxysporum was evaluated, using five different extract concentrations of 0.5%, 1.0%, 1.5%, 2.5%, and 3.5% w/v. These fungi were isolated from rotted tubers of D. rotundata, across three agroecological zones in Nigeria-the Humid rainforest, Derived savanna, and southern Guinea savanna. All treatments were subjected to three methods of inoculation 48 hours before the application of both extracts and stored at 28?±?2°C for 6 months. Radial mycelial growth of the test pathogens was effectively inhibited at concentrations???3.5% w/v in vitro for both OSH and QP extracts. Rotting was significantly reduced (P???0.05) to between 0 to 18.8% and 0% to 20.9% for OSH and QP extracts respectively. The extracts significantly (P???0.05) inhibited percent rot of the test pathogens at 3.5% concentration w/v in vivo. Rot incidence was, however, lower in replicate tubers that were inoculated, treated with extracts and exposed than treatments that were covered. Phytochemical analysis of OSH and QP extracts revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, tannins, ferulic acid, phlobatanins, Terpenoids, phenols, anthraquinone and pyroligneous acid. The efficacy of both extracts in reducing rot in this study recommends their development as prospective biopesticide formulation and use in the management of post-harvest rot of yam tubers. PMID:25674452

  19. Ubiquitous urease affects soybean susceptibility to fungi.

    PubMed

    Wiebke-Strohm, Beatriz; Pasquali, Giancarlo; Margis-Pinheiro, Márcia; Bencke, Marta; Bücker-Neto, Lauro; Becker-Ritt, Arlete B; Martinelli, Anne H S; Rechenmacher, Ciliana; Polacco, Joseph C; Stolf, Renata; Marcelino, Francismar C; Abdelnoor, Ricardo V; Homrich, Milena S; Del Ponte, Emerson M; Carlini, Celia R; De Carvalho, Mayra C C G; Bodanese-Zanettini, Maria Helena

    2012-05-01

    The soybean ubiquitous urease (encoded by GmEu4) is responsible for recycling metabolically derived urea. Additional biological roles have been demonstrated for plant ureases, notably in toxicity to other organisms. However, urease enzymatic activity is not related to its toxicity. The role of GmEu4 in soybean susceptibility to fungi was investigated in this study. A differential expression pattern of GmEu4 was observed in susceptible and resistant genotypes of soybeans over the course of a Phakopsora pachyrhizi infection, especially 24 h after infection. Twenty-nine adult, transgenic soybean plants, representing six independently transformed lines, were obtained. Although the initial aim of this study was to overexpress GmEu4, the transgenic plants exhibited GmEu4 co-suppression and decreased ureolytic activity. The growth of Rhizoctonia solani, Phomopsis sp., and Penicillium herguei in media containing a crude protein extract from either transgenic or non-transgenic leaves was evaluated. The fungal growth was higher in the protein extracts from transgenic urease-deprived plants than in extracts from non-transgenic controls. When infected by P. pachyrhizi uredospores, detached leaves of urease-deprived plants developed a significantly higher number of lesions, pustules and erupted pustules than leaves of non-transgenic plants containing normal levels of the enzyme. The results of the present work show that the soybean plants were more susceptible to fungi in the absence of urease. It was not possible to overexpress active GmEu4. For future work, overexpression of urease fungitoxic peptides could be attempted as an alternative approach. PMID:22382992

  20. Bahiagrass, Corn, Cotton Rotations, and Pesticides for Managing Nematodes, Diseases, and Insects on Peanut

    PubMed Central

    Johnson, A. W.; Minton, N. A.; Brenneman, T. B.; Burton, G. W.; Culbreath, A. K.; Gascho, G. J.; Baker, S. H.

    1999-01-01

    Florunner peanut was grown after 1 and 2 years of Tifton 9 bahiagrass, corn, cotton, and continuous peanut as whole-plots. Pesticide treatments aldicarb (3.4 kg a.i./ha), flutolanil (1.7 kg a.i./ha), aldicarb + flutolanil, and untreated (control) were sub-plots. Numbers of Meloidogyne arenaria second-stage juveniles in the soil and root-gall indices of peanut at harvest were consistently lower in plots treated with aldicarb and aldicarb + flutolanil than in flutolanil-treated and untreated plots. Percentages of peanut leaflets damaged by thrips and leafhoppers were consistently greater in flutolaniltreated and untreated plots than in plots treated with aldicarb or aldicarb + flutolanil but not affected by cropping sequences. Incidence of southern stem rot was moderate to high for all chemical treatments except those that included flutolanil. Stem rot loci were low in peanut following 2 years of bahiagrass, intermediate following 2 years of corn or cotton, and highest in continuous peanut. Rhizoctonia limb rot was more severe in the peanut monoculture than in peanut following 2 years of bahiagrass, corn, or cotton. Flutolanil alone or combined with aldicarb suppressed limb rot compared with aldicarb-treated and untreated plots. Peanut pod yields were 4,186 kg/ha from aldicarb + flutolanil-treated plots, 3,627 kg/ha from aldicarb-treated plots, 3,426 kg/ha from flutolanil-treated plots, and 3,056 kg/ha from untreated plots. Yields of peanut following 2 years of bahiagrass, corn, and cotton were 29% to 33% higher than yield of monocultured peanut. PMID:19270889

  1. Peanut-Cotton-Rye Rotations and Soil Chemical Treatment for Managing Nematodes and Thrips

    PubMed Central

    Johnson, A. W.; Minton, N. A.; Brenneman, T. B.; Todd, J. W.; Herzog, G. A.; Gascho, G. J.; Baker, S. H.; Bondari, Y.

    1998-01-01

    In the southeastern United States, a cotton-peanut rotation is attractive because of the high value and extensive planting of both crops in the region. The objective of this experiment was to determine the effects of cotton-peanut rotations, rye, and soil chemical treatments on management of plant-parasitic nematodes, thrips, and soilborne fungal diseases and on crop yield. Peanut-cotton-rye rotations were conducted from 1988 to 1994 on Tifton loamy sand (Plinthic Kandiudult) infested primarily with Meloidogyne incognita race 3, Belonolaimus longicaudatus, Sclerotium rolfsii, Rhizoctonia solani, and Fusarium oxysporum. Continuous peanut, continuous cotton, cotton-peanut rotation, or peanut-cotton rotation were used as main plots; winter rye or fallow as sub-plots; and cotton with and without aldicarb (3.36 kg a.i./ha), or peanut with and without aldicarb (3.36 kg a.i./ha) plus flutolanil (1.12 kg a.i./ha), as sub-sub-plots. Population densities of M. incognita and B. longicaudatus declined rapidly after the first crop in continuous peanut and remained low thereafter. Neither rye nor soil chemical treatment affected M. incognita or B. longicaudatus population density on peanut or cotton. Cotton and peanut yields from the cotton-peanut rotation were 26% and 10% greater, respectively, than those from monoculmre over the 7-year study. Cotton and peanut yields were improved 9% and 4%, respectively, following rye vs. fallow. Soil chemical treatments increased yields of cotton 23% and peanut 32% over those of untreated plots. Our data demonstrate the sustainable benefits of using cotton-peanut rotations, winter rye, and soil chemical treatments to manage plant-parasitic nematodes and other pests and pathogens and improve yield of both cotton and peanut. PMID:19274213

  2. Improvement of the Fungal Biocontrol Agent Trichoderma atroviride To Enhance both Antagonism and Induction of Plant Systemic Disease Resistance

    PubMed Central

    Brunner, Kurt; Zeilinger, Susanne; Ciliento, Rosalia; Woo, Sheridian L.; Lorito, Matteo; Kubicek, Christian P.; Mach, Robert L.

    2005-01-01

    Biocontrol agents generally do not perform well enough under field conditions to compete with chemical fungicides. We determined whether transgenic strain SJ3-4 of Trichoderma atroviride, which expresses the Aspergillus niger glucose oxidase-encoding gene, goxA, under a homologous chitinase (nag1) promoter had increased capabilities as a fungal biocontrol agent. The transgenic strain differed only slightly from the wild-type in sporulation or the growth rate. goxA expression occurred immediately after contact with the plant pathogen, and the glucose oxidase formed was secreted. SJ3-4 had significantly less N-acetylglucosaminidase and endochitinase activities than its nontransformed parent. Glucose oxidase-containing culture filtrates exhibited threefold-greater inhibition of germination of spores of Botrytis cinerea. The transgenic strain also more quickly overgrew and lysed the plant pathogens Rhizoctonia solani and Pythium ultimum. In planta, SJ3-4 had no detectable improved effect against low inoculum levels of these pathogens. Beans planted in heavily infested soil and treated with conidia of the transgenic Trichoderma strain germinated, but beans treated with wild-type spores did not germinate. SJ3-4 also was more effective in inducing systemic resistance in plants. Beans with SJ3-4 root protection were highly resistant to leaf lesions caused by the foliar pathogen B. cinerea. This work demonstrates that heterologous genes driven by pathogen-inducible promoters can increase the biocontrol and systemic resistance-inducing properties of fungal biocontrol agents, such as Trichoderma spp., and that these microbes can be used as vectors to provide plants with useful molecules (e.g., glucose oxidase) that can increase their resistance to pathogens. PMID:16000810

  3. Spectroscopic studies and biological evaluation of some transition metal complexes of azo Schiff-base ligand derived from (1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one) and 5-((4-chlorophenyl)diazenyl)-2-hydroxybenzaldehyde

    NASA Astrophysics Data System (ADS)

    Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Sumathi, S.

    2012-10-01

    A series of metal(II) complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the azo Schiff base ligand 4-((E)-4-((E)-(4-chlorophenyl)diazenyl)-2-hydroxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (CDHBAP) and characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR, ESR and EI-mass), magnetic moment measurements, molar conductance, DNA, SEM, X-ray crystallography and fluorescence studies. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate square pyramidal geometry for VO(II) and octahedral geometry for all the other complexes. The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied and implies that CDHBAP is coordinated to the metal ions in a neutral tridentate manner. The redox behavior of copper(II) and vanadyl(II) complexes have been studied by cyclic voltammetry. The nuclease activity of the above metal(II) complexes shows that the complexes cleave DNA. All the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The antibacterial and antifungal activities of the synthesized ligand and its metal complexes were screened against bacterial species (Staphylococcus aureus, Salmonella typhi, Escherichia coli, Bacillus subtilis, Shigella sonnie) and fungi (Candida albicans, Aspergillus niger, Rhizoctonia bataicola). Amikacin and Ketoconozole were used as references for antibacterial and antifungal studies. The activity data show that the metal complexes have a promising biological activity comparable with the parent Schiff base ligand against bacterial and fungal species. The second harmonic generation (SHG) efficiency of the ligand was measured and the NLO (non-linear optical) properties of the ligand are expected to result in the realization of advanced optical devices in optical fiber communication (OFC) and optical computing. The SEM image of the copper(II) complex implies that the size of the particles is 1 ?m.

  4. Penetration through the peritrophic matrix is a key to lectin toxicity against Tribolium castaneum.

    PubMed

    Walski, Tomasz; Van Damme, Els J M; Smagghe, Guy

    2014-11-01

    In the last decades lectins have received a lot of attention as potential tools in pest control. Despite substantial progress in the field not all the factors determining insecticidal potency and selectivity of these proteins have been described. Recently, three lectins, RSA (Rhizoctonia solani agglutinin), SNA-I and SNA-II (Sambucus nigra agglutinin I and II) have been shown to be toxic to aphids and caterpillars. In this project we investigated if these lectins are also toxic against larvae and a cell line of the red flour beetle, Tribolium castaneum, a model organism and important pest of stored products. Furthermore, we analyzed the stability of the lectins in the larval gut and used confocal microscopy to compare their efficiency in passing through the peritrophic matrix (PM). We observed that all three lectins were toxic against the T. castaneum cell line and their effectiveness in vitro was in decreasing order SNA-II>SNA-I>RSA with the respective EC50 being 0.1, 0.5 and 3.6 ?g/ml. Larvae feeding for 16 day on diets containing 2% RSA, 2% SNA-II and 2% SNA-I weighed 0.14 ± 0.07 mg, 0.67 ± 0.44 mg and 1.89 ± 0.38 mg, corresponding to approximately 7%, 36% and 80% of control larvae, respectively. As a consequence, RSA increased the time to adult emergence by over 3-fold, SNA-II by 1.9-fold and SNA-I by 1.2-fold. RSA and SNA-II were stable in the larval gut, while SNA-I was digested and excreted with the feces. Finally, confocal microscopy confirmed that RSA passed through the PM more efficiently than SNA-II. In conclusion, our data suggest that the lectin ability to pass through the PM, governed by molecule dimensions, charge and size of PM pores, is one of the features that determine the toxicity of these insecticidal proteins. PMID:25240534

  5. Differential effectiveness of Serratia plymuthica IC1270-induced systemic resistance against hemibiotrophic and necrotrophic leaf pathogens in rice

    PubMed Central

    De Vleesschauwer, David; Chernin, Leonid; Höfte, Monica M

    2009-01-01

    Background Induced resistance is a state of enhanced defensive capacity developed by a plant reacting to specific biotic or chemical stimuli. Over the years, several forms of induced resistance have been characterized, including systemic acquired resistance, which is induced upon localized infection by an avirulent necrotizing pathogen, and induced systemic resistance (ISR), which is elicited by selected strains of nonpathogenic rhizobacteria. However, contrary to the relative wealth of information on inducible defense responses in dicotyledoneous plants, our understanding of the molecular mechanisms underlying induced resistance phenomena in cereal crops is still in its infancy. Using a combined cytomolecular and pharmacological approach, we analyzed the host defense mechanisms associated with the establishment of ISR in rice by the rhizobacterium Serratia plymuthica IC1270. Results In a standardized soil-based assay, root treatment with IC1270 rendered foliar tissues more resistant to the hemibiotrophic pathogen Magnaporthe oryzae, causal agent of the devastating rice blast disease. Analysis of the cytological and biochemical alterations associated with restriction of fungal growth in IC1270-induced plants revealed that IC1270 primes rice for enhanced attacker-induced accumulation of reactive oxygen species (ROS) and autofluorescent phenolic compounds in and near epidermal cells displaying dense cytoplasmic granulation. Similar, yet more abundant, phenotypes of hypersensitively dying cells in the vicinity of fungal hyphae were evident in a gene-for-gene interaction with an avirulent M. oryzae strain, suggesting that IC1270-inducible ISR and R protein conditioned effector-triggered immunity (ETI) target similar defense mechanisms. Yet, this IC1270-inducible ISR response seems to act as a double-edged sword within the rice defense network as induced plants displayed an increased vulnerability to the necrotrophic pathogens Rhizoctonia solani and Cochliobolus miyabeanus. Artificial enhancement of ROS levels in inoculated leaves faithfully mimicked the opposite effects of IC1270 bacteria on aforementioned pathogens, suggesting a central role for oxidative events in the IC1270-induced resistance mechanism. Conclusion Besides identifying ROS as modulators of antagonistic defense mechanisms in rice, this work reveals the mechanistic similarities between S. plymuthica-mediated ISR and R protein-dictated ETI and underscores the importance of using appropriate innate defense mechanisms when breeding for broad-spectrum rice disease resistance. PMID:19161601

  6. Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn

    PubMed Central

    Chowdhary, Kanika; Kaushik, Nutan

    2015-01-01

    Endophytic mycopopulation isolated from India’s Queen of herbs Tulsi (Ocimum sanctum) were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues) from three different geographic locations (Delhi, Hyderabad and Mukteshwar) during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011) in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907) whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846). Mukteshwar (altitude: 7500 feet) reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in antiphytopathogenic activity of hexane extract. The production of 2H-pyran-2-one, 5,6-dihydro-6-pentyl from M. phaseolina, an endophytic fungus is being reported for the first time. PMID:26529087

  7. Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn.

    PubMed

    Chowdhary, Kanika; Kaushik, Nutan

    2015-01-01

    Endophytic mycopopulation isolated from India's Queen of herbs Tulsi (Ocimum sanctum) were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues) from three different geographic locations (Delhi, Hyderabad and Mukteshwar) during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011) in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907) whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846). Mukteshwar (altitude: 7500 feet) reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in antiphytopathogenic activity of hexane extract. The production of 2H-pyran-2-one, 5,6-dihydro-6-pentyl from M. phaseolina, an endophytic fungus is being reported for the first time. PMID:26529087

  8. How do microorganisms influence trace element uptake by plants? Screening in an agar model rhizosphere.

    NASA Astrophysics Data System (ADS)

    Marchetti, M.; Robinson, B. H.; Evangelou, M. W. H.; Vachey, A.; Schwitzguebel, J. P.; Bernier-Latmani, R.; Schulin, R.

    2009-04-01

    Trace elements (TE) are essential for humans and plants, but they may be toxic if their concentration is too high. For this reason, the management of TE in soils is very important. In some cases it may be necessary to increase the uptake of nutrients or TE by plants, for example in a biofortification perspective. Conversely, in some other cases TE uptake by plants should be decreased, for instance to avoid heavy metals entering the food chain via edible crops. Microorganisms living in the rhizosphere affect trace element (TE) uptake by plants. However, due to the complexity of this space and the variety of microorganisms that occur there, it is difficult to isolate the effect of any particular strain. To overcome this hurdle, we developed a system in which we grew plants under sterile conditions in agar and inoculated their rhizosphere with a single, well-defined microbial strain. For many years, agar has been used as a growth substrate for microorganisms and plant tissues. It is cheap, easy to use, and can be autoclaved to ensure its sterility. Because of its widespread use, an experiment conducted using this substrate can be reproduced under the same conditions in any laboratory. In contrast to soil, there is little interaction between the trace elements and the agar matrix. There are many studies investigating the influence of microorganisms on TE uptake by plants. However, so far only a small variety of microorganisms has been tested on few plant species. Therefore, the first objective of our research was to develop a method to rapidly screen a large variety of microorganisms on various plant species. Once this goal was achieved, we sought to study the effect of single, well-defined microbial strains on TE uptake by sunflower and wheat. The substrate for plants growth was a 10% agar solution prepared with modified Hoagland's solution and a TE solution containing 1 mg/kg Pb and molar equivalents of Cu, Ni and Zn. The agar solution was autoclaved and poured into sterile, transparent plastic boxes, whose lid was equipped with a filter allowing gas exchanges without contamination by external microorganisms. The seed surface was sterilised and the plants grew one week in agar before their rhizosphere was inoculated with LB broth containing a pure bacterial strain or agar plugs colonized by fungal hyphae. We tested 14 strains, with 5 replicates per treatment and a control where the system was inoculated with sterile LB broth. The plants grew for 2 weeks in a climate chamber and their shoots were analysed for their TEs by ICP-OES. Samples of agar and roots were collected to confirm microbial colonization of the rhizosphere, respectively sterile conditions in the control treatments. Concerning the method development, the plants grew without visible toxicity in all the boxes, and the analysis of root and agar samples indicated that the controls were sterile and the strains inoculated were growing along the roots. More than 90% of the TE and nutrients added to the system were in the liquid fraction of the agar medium, thus available for root uptake. The screening showed that the microorganisms in general decreased TE uptake by wheat and sunflower, although some of them had an opposite effect on the plants. However, with the same plant species, the microorganisms had a consistent effect on all TE tested, i.e. a given single strain caused the same effect (increase or decrease of TE uptake) on all TE tested. In sunflower, 3 microorganisms (Paenibacillus polymyxa, Pythium ultimum and Rhizoctonia solani) decreased Cu and Zn uptake by 50% compared to the control treatment. These three species are common soil microorganisms. All three are known to exude auxin, a phytohormone. This hormone can modify root morphology and physiology and thus may affect TE uptake by plants. R. solani and P. ultimum are root pathogens. Their effect was opposite to what we expected. If roots are damaged, TE should have flooded into the plant and accumulate in the tissues, but this was not the case. One explanation could be the biosorption of TE by these mi