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Sample records for tridentatacontra rhizoctonia solanien

  1. Rhizoctonia web blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...

  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 solani: Understanding the Terminology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani can cause seedling damping-off and root rot in dry bean and a number of other major crops including sugarbeet, soybean, cotton, potato, etc. There appears to be an increase in reported incidence in both temperate regions and in tropical areas. As well as a root rot, some stains ca...

  4. Rhizoctonia seedling disease on sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia seedling damping-off can cause losses in sugar beet as well as providing inoculum for later root rot. The disease is caused by Rhizoctonia solani. The pathogen has several subgroups, anastomosis groups (AG), of which AG-4 has historically been associated with damping-off, while AG-2-2 is...

  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. 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...

  7. 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. ...

  8. Bi-fluorescence imaging for estimating accurately the nuclear condition of Rhizoctonia spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the absence of perfect state, the number of nuclei in their vegetative hyphae is one of the anamorphic features that separate Rhizoctonia solani from other Rhizoctonia-like fungi. Anamorphs of Rhizoctonia solani are typically multinucleate while the other Rhizoctonia species are binucleate. Howev...

  9. 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...

  10. 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) ...

  11. 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...

  12. 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...

  13. 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...

  14. Sugar Beet Resistance to Rhizoctonia Root and Crown Rot: Where does it fit in?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In sugar beet (Beta vulgaris L.), Rhizoctonia root- or crown-rot is caused by Rhizoctonia solani (AG-2-2). Seedling damping-off in sugar beet is caused by R. solani of both anastomosis groups, AG-2-2 and AG-4. Rhizoctonia solani subgroup AG-2-2 IV had been considered to be the primary cause of Rhi...

  15. A rare case of human mycosis by Rhizoctonia solani.

    PubMed

    Kaore, N M; Atul, A R; Khan, M Z; Ramnani, V K

    2012-01-01

    Rhizoctonia solani is a most widely recognized strong saprophyte with a great diversity of host plants. It is a first ever case of extensive human mycosis caused by Rhizoctonia solani in a 65-year-old diabetic and hypertensive farmer, with a history of head injury caused by fall of mud wall. Necrotic material collected revealed septate fungal hyphae with bacterial co-infection. Fungal culture on SDA at 25°C showed cotton wooly growth progressing to greyish-white to shiny metallic black colonies and identified on basis of septate mycelial growth without conidia, right angle branching, presence of compact hyphal forms and anastomosis between branching hyphae on LPCB mount.

  16. Rhizoctonia seedling damping-off in sugar beet in Michigan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is an important seedling pathogen of sugar beet, causing damping-off following seedling emergence. Anastomosis group (AG)-4 has been the primary seedling pathogen reported on sugar beet, however, recent screening has found high incidence of infection by AG-2-2. Isolations of R. so...

  17. The Pathogen Biology, Identification and Management of Rhizoctonia Diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani is an economically important soilborne pathogen causing economic losses to crops, vegetables, ornamentals, forest trees and turfgrasses. The pathogenic isolates may belong to diverse genera and species and are variously responsible for pre- or post-emergence damping off of seedlin...

  18. 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...

  19. Characterization and pathogenicity of Rhizoctonia and Rhizoctonia-like spp. from pea crops in the Columbia Basin of Oregon and Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 179 isolates of Rhizoctonia and Rhizoctonia-like species were obtained from soil and plant samples collected from irrigated pea crops in the semi-arid Columbia Basin of Oregon and Washington from 2011 to 2013, and characterized to species, subspecies, and anastomosis groups (AG) based on ...

  20. Novel mitoviruses in Rhizoctonia solani AG-3PT infecting potato.

    PubMed

    Das, Subha; Falloon, Richard E; Stewart, Alison; Pitman, Andrew R

    2016-03-01

    Double-stranded RNA (dsRNA) elements are ubiquitous in Rhizoctonia solani. Total dsRNA was randomly amplified from a R. solani isolate (RS002) belonging to anastomosis group-3PT (AG-3PT), associated with black scurf in potato. Assembly of resulting cDNA sequences identified a nearly complete genome of a novel virus related to the genus Mitovirus (family Narnaviridae), herein named Rhizoctonia mitovirus 1 RS002 (RMV-1-RS002). The 2797 nucleotide partial genome of RMV-1-RS002 is A-U rich (59.06 %), and can be folded into stable stem-loop structures at 5' and 3' ends. Universal and mold mitochondrial codon usages revealed a large open reading frame in the genome, putatively encoding an 826 amino acid polypeptide, which has conserved motifs for mitoviral RNA-dependent RNA polymerase. The full length putative polypeptide shared 25.6 % sequence identity with the corresponding region of Tuber excavatum mitovirus (TeMV). The partial genome of a second mitovirus (proposed name Rhizoctonia mitovirus 2 RS002 (RMV-2-RS002)) was also amplified from RS002. A nearly identical copy of RMV-1-RS002 was detected in two additional AG-3PT isolates. These data indicate that multiple mitoviruses can exist in a single isolate of R. solani AG-3PT, and that mitoviruses such as RMV-1-RS002 are probably widespread in this pathogen. The roles of mitoviruses in the biology of R. solani AG-3PT remain unknown.

  1. 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...

  2. Chemical and Hot Water Treatments to Eliminate Rhizoctonia From Azalea Stem Cuttings: Failures and Successes

    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...

  3. Chemical and hot water treatments to control Rhizoctonia AG P infesting stem cuttings of azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the southern and eastern U.S., azalea 'Gumpo' stems cut during the spring for propagation may be infested with Rhizoctonia spp. Multiple methods were evaluated for the purpose of eliminating Rhizoctonia spp. from stem cuttings to prevent spread into the propagation house. Stems were inoculated w...

  4. 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...

  5. 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...

  6. Identification of resistance to Rhizoctonia root rot in mutant and wild barley (Hordeum vulgare subsp. spontaneum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct seeding cereal crops into non-tilled fields is a practice that is gaining importance in the Pacific Northwest region of the United States. Unfortunately, Rhizoctonia root rot and bare-patch caused by Rhizoctonia solani AG-8 limits the yield of direct-seeded cereals in this region. No resistan...

  7. 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 ...

  8. 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...

  9. Leuconostoc spp. associated with root rot in sugar beet and their interaction with rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root and crown is an important disease problem in sugar beet caused by Rhizoctonia solani and also shown to be associated with Leuconostoc. Since, the initial Leuconostoc studies were conducted with only a few isolates and the relationship of Leuconostoc with R. solani is poorly underst...

  10. 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...

  11. Preparation of 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...

  12. Preparation of Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trail

    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...

  13. 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...

  14. Preparation of inoculum of Rhizoctonia solani Kühn 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...

  15. 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...

  16. 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...

  17. 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...

  18. Rhizoctonia root rot resistance in experimental 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 experimental sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface ...

  19. Potential of spreading binucleate Rhizoctonia from nursery propagation floors to trays containing azalea stem cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Binucleate Rhizoctonia fungi cause web blight on azaleas and other woody ornamental plants. This research focused on one aspect of how the pathogen may spread from contaminated floors of propagation houses into trays containing clean azalea stem cuttings that generate new root systems. Rhizoctonia w...

  20. Proteomic analysis of Rhizoctonia solani AG-1 sclerotia maturation.

    PubMed

    Kwon, Young Sang; Kim, Sang Gon; Chung, Woo Sik; Bae, Hanhong; Jeong, Sung Woo; Shin, Sung Chul; Jeong, Mi-Jeong; Park, Soo-Chul; Kwak, Youn-Sig; Bae, Dong-Won; Lee, Yong Bok

    2014-01-01

    Rhizoctonia solani (R. solani), a soil-borne necrotrophic pathogen, causes various plant diseases. Rhizoctonia solani is a mitosporic fungus, the sclerotium of which is the primary inoculum and ensures survival of the fungus during the offseason of the host crop. Since the fungus does not produce any asexual or sexual spores, understanding the biology of sclerotia is important to examine pathogen ecology and develop more efficient methods for crop protection. Here, one- and two-dimensional gel electrophoresis (1-DE and 2-DE, respectively) were used to examine protein regulation during the maturation of fungal sclerotia. A total of 75 proteins (20 proteins from 1-DE using matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) and 55 proteins from 2-DE using MALDI-TOF MS or MALDI-TOF/TOF MS) were differentially expressed during sclerotial maturation. The identified proteins were classified into ten categories based on their biological functions, including genetic information processing, carbohydrate metabolism, cell defense, amino acid metabolism, nucleotide metabolism, cellular processes, pathogenicity and mycotoxin production, and hypothetical or unknown functions. Interestingly, two vacuole function-related proteins were highly up-regulated throughout sclerotial maturation, which was confirmed at the transcript level by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. These findings contribute to our understanding of the biology of R. solani sclerotia.

  1. Phylogenetic relationships of Rhizoctonia fungi within the Cantharellales

    PubMed Central

    Gónzalez, Dolores; Rodriguez-Carres, Marianela; Boekhout, Teun; Stalpers, Joost; Kuramae, Eiko E.; Nakatani, Andreia K.; Vilgalys, Rytas; Cubeta, Marc A.

    2016-01-01

    Phylogenetic relationships of Rhizoctonia fungi within the order Cantharellales were studied using sequence data from portions of the ribosomal DNA cluster regions ITS-LSU, rpb2, tef1 and atp6 for 50 taxa, and public sequence data from the rpb2 locus for 165 taxa. Data sets were analyzed individually and combined using Maximum Parsimony, Maximum Likelihood and Bayesian Phylogenetic Inference methods. All analyses supported the monophyly of the family Ceratobasidiaceae, which comprises the genera Ceratobasidium and Thanatephorus. Multi-locus analysis revealed 10 well supported monophyletic groups that were consistent with previous separation into anastomosis groups based on hyphal fusion criteria. This analysis coupled with analyses of a larger sample of 165 rpb2 sequences of fungi in the Cantharellales supported a sister relationship between the Botryobasidiaceae and Ceratobasidiaceae and a sister relationship of the Tulasnellaceae with the rest of the Cantharellales. The inclusion of additional sequence data did not clarify incongruences observed in previous studies of Rhizoctonia fungi in the Cantharellales based on analyses of a single or multiple genes. The diversity of ecological and morphological characters associated with these fungi requires further investigation on character evolution for re-evaluating homologous and homoplasious characters. PMID:27020160

  2. Purification and identification of Bacillus subtilis SPB1 lipopeptide biosurfactant exhibiting antifungal activity against Rhizoctonia bataticola and Rhizoctonia solani.

    PubMed

    Mnif, Inès; Grau-Campistany, Ariadna; Coronel-León, Jonathan; Hammami, Inès; Triki, Mohamed Ali; Manresa, Angeles; Ghribi, Dhouha

    2016-04-01

    This study reports the potential of a soil bacterium, Bacillus subtilis strain SPB1, to produce lipopeptide biosurfactants. Firstly, the crude lipopeptide mixture was tested for its inhibitory activity against phytopathogenic fungi. A minimal inhibitory concentration (MIC), an inhibitory concentration at 50% (IC50%), and an inhibitory concentration at 90% (IC90%) values were determined to be 0.04, 0.012, and 0.02 mg/ml, respectively, for Rhizoctonia bataticola with a fungistatic mode of action. For Rhizoctonia solani, a MIC, an IC50%, and IC90% values were determined to be 4, 0.25, and 3.3 mg/ml, respectively, with a fungicidal mode of action. For both of the fungi, a loss of sclerotial integrity, granulation and fragmentation of hyphal mycelia, followed by hyphal shriveling and cell lysis were observed with the treatment with SPB1 biosurfactant fraction. After extraction, separation, and purification, different lipopeptide compounds were identified in the culture filtrate of strain SPB1. Mass spectroscopic analysis confirmed the presence of different lipopeptide compounds consisting of surfactin isoforms with molecular weights of 1007, 1021, and 1035 Da; iturin isoforms with molecular weights of 1028, 1042, and 1056 Da; and fengycin isoforms with molecular weights of 1432 and 1446 Da. Two new clusters of lipopeptide isoforms with molecular weights of 1410 and 1424 Da and 973 and 987 Da, respectively, were also detected. This study reported the ability of a B. subtilis strain to co-produce lipopeptide isoforms with potential use as antifungal compounds.

  3. Biological control of soilborne diseases in organic potato production using hypovirulent strains of Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soilborne diseases are persistent problems in potato production and alternative management practices are needed, particularly in organic production, where control options are limited. Selected biocontrol organisms, including two naturally-occurring hypovirulent strains of Rhizoctonia solani (Rhs1a1 ...

  4. Lysine catabolism in Rhizoctonia leguminicola and related fungi.

    PubMed Central

    Guengerich, F P; Broquist, H P

    1976-01-01

    The catabolism of lysine was studied in several yeasts and fungi. Results with cell-free extracts of Rhizoctonia leguminicola support a proposed pathway involving (D- and L-) EPSILON-N-acetyllysine, alpha-keto-epsilon-acetamidohexanoic acid, delta-acetamidovaleric acid, and delta-aminovaleric acid in the conversion of L-lysine to shortchain organic acids. Label from radioactive L-lysine was found to accumulate in D- and L-epsilon-N-acetyllysine, delta-acetamidovaleric acid, delta-aminovaleric acid, and glutaric acid in cultures of R. leguminicola, Neurospora crassa, Saccharomyces cerevisiae, and Hansenula saturnus, suggesting that the proposed omega-acetyl pathway of lysine catabolism is generalized among yeasts and fungi. In N. crassa, as is the case in R. leguminicola, the major precursor of L-pipecolic acid was the L-isomer of lysine; 15N experiments were consistent with delta1-piperideine-2-carboxylic acid as an intermediate in the transformation. PMID:131119

  5. Lysine catabolism in Rhizoctonia leguminicola and related fungi.

    PubMed

    Guengerich, F P; Broquist, H P

    1976-04-01

    The catabolism of lysine was studied in several yeasts and fungi. Results with cell-free extracts of Rhizoctonia leguminicola support a proposed pathway involving (D- and L-) EPSILON-N-acetyllysine, alpha-keto-epsilon-acetamidohexanoic acid, delta-acetamidovaleric acid, and delta-aminovaleric acid in the conversion of L-lysine to shortchain organic acids. Label from radioactive L-lysine was found to accumulate in D- and L-epsilon-N-acetyllysine, delta-acetamidovaleric acid, delta-aminovaleric acid, and glutaric acid in cultures of R. leguminicola, Neurospora crassa, Saccharomyces cerevisiae, and Hansenula saturnus, suggesting that the proposed omega-acetyl pathway of lysine catabolism is generalized among yeasts and fungi. In N. crassa, as is the case in R. leguminicola, the major precursor of L-pipecolic acid was the L-isomer of lysine; 15N experiments were consistent with delta1-piperideine-2-carboxylic acid as an intermediate in the transformation.

  6. Development of SCAR markers and UP-PCR cross-hybridization method for specific detection of four major subgroups of Rhizoctonia from infected turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several species and hyphal anastomosis groups (AG) of Rhizoctonia solani (sensu lato) cause brown patch diseases of turfgrasses. Conventional methods of identification of Rhizoctonia pathogens are time consuming and often inaccurate. A rapid identification assay for Waitea circinata (anamorph: Rhizo...

  7. The influence of soil moisture and Rhizoctonia solani anastomosis and intraspecific group on the incidence of damping-off and the incidence and severity of Rhizoctonia crown and root rot in sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown and root rot (Rhizoctonia solani) reduces plant stands, sugar quality and yield in sugar beet. To evaluate the influence of R. solani anastomosis (AG) and intraspecific groups and soil moisture on disease incidence and severity, a field trial was established in Ridgetown, Ontario, ...

  8. Interactions between cauliflower and Rhizoctonia anastomosis groups with different levels of aggressiveness

    PubMed Central

    Pannecoucque, Joke; Höfte, Monica

    2009-01-01

    Background The soil borne fungus Rhizoctonia is one of the most important plant pathogenic fungi, with a wide host range and worldwide distribution. In cauliflower (Brassica oleracea var. botrytis), several anastomosis groups (AGs) including both multinucleate R. solani and binucleate Rhizoctonia species have been identified showing different levels of aggressiveness. The infection and colonization process of Rhizoctonia during pathogenic interactions is well described. In contrast, insights into processes during interactions with weak aggressive or non-pathogenic isolates are limited. In this study the interaction of cauliflower with seven R. solani AGs and one binucleate Rhizoctonia AG differing in aggressiveness, was compared. Using microscopic and histopathological techniques, the early steps of the infection process, the colonization process and several host responses were studied. Results For aggressive Rhizoctonia AGs (R. solani AG 1-1B, AG 1-1C, AG 2-1, AG 2-2 IIIb and AG 4 HGII), a higher developmental rate was detected for several steps of the infection process, including directed growth along anticlinal cell walls and formation of T-shaped branches, infection cushion formation and stomatal penetration. Weak or non-aggressive AGs (R. solani AG 5, AG 3 and binucleate Rhizoctonia AG K) required more time, notwithstanding all AGs were able to penetrate cauliflower hypocotyls. Histopathological observations indicated that Rhizoctonia AGs provoked differential host responses and pectin degradation. We demonstrated the pronounced deposition of phenolic compounds and callose against weak and non-aggressive AGs which resulted in a delay or complete block of the host colonization. Degradation of pectic compounds was observed for all pathogenic AGs, except for AG 2-2 IIIb. Ranking the AGs based on infection rate, level of induced host responses and pectin degradation revealed a strong correlation with the disease severity caused by the AGs. Conclusion The

  9. Genetic diversity and virulence of Rhizoctonia species associated with plantings of Lotus corniculatus.

    PubMed

    Emery, Keith M; Beuselinck, Paul R; English, James T

    2003-02-01

    Species of Rhizoctonia cause a blight of Lotus corniculatus, a perennial forage legume. We characterized genetic variation and virulence in populations of R. solani and binucleate Rhizoctonia's associated with diseased L. corniculatus in field plantings over several years. Isolates of anastomosis groups AG-1 and AG-4 accounted for the R. solani recovered from diseased leaf and shoot tissues. Isolates of binucleate Rhizoctonia were recovered predominantly from soil and associated plant debris. Isolates of R. solani were more virulent on leaves and shoots of L. corniculatus than were binucleate Rhizoctonia isolates. Numerous unique DNA restriction patterns were observed among binucleate isolates and anastomosis groups of R. solani. Variation in restriction patterns was greater among isolates of AG-1 from the lower plant canopy than from the upper canopy. No restriction pattern was shared by any isolate from AG-1 and AG-4. Allelic and genotypic heterogeneity of AG-1 isolates were also greater in the lower plant canopy. Binucleate isolates exhibited greater heterogeneity than AG-1 isolates from either canopy region. L. corniculatus offers significant opportunities for investigating temporal and spatial dynamics of genetic structure of Rhizoctonia populations in perennial plant systems.

  10. 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...

  11. 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...

  12. The role of bacterial communities in the natural suppression of Rhizoctonia bare patch of wheat Triticum aestivum L

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia bare patch and root rot of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants, and limits the yield of direct-seeded wheat in the Pacific Northwest (PNW) of the United States. At a long-term wheat cropping systems study site near Ritzville, WA, conve...

  13. Metabolome profiling to understand the defense response to sugar beet (Beta vulgaris) to Rhizoctonia solani AG 2-2 IIIB

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia crown and root rot, caused by Rhizoctonia solani Kühn AG 2-2 IIIB, is an important disease of sugar beet (Beta vulgaris L.). The molecular processes that mediate sugar beet resistance to R. solani are largely unknown and identifying the metabolites associated with R. solani infection ma...

  14. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot and damping-off, caused by Rhizoctonia solani, are among the most economically important root and hypocotyl diseases in the world and affect a wide range of hosts including the common bean (Phaseolus vulgaris). To identify potential sources of resistance, screening material was ...

  16. 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...

  17. Biochar Amendment Modifies Expression of Soybean and Rhizoctonia solani Genes Leading to Increased Severity of Rhizoctonia Foliar Blight.

    PubMed

    Copley, Tanya; Bayen, Stéphane; Jabaji, Suha

    2017-01-01

    Application of biochar, a pyrolyzed biomass from organic sources, to agricultural soils is considered a promising strategy to sustain soil fertility leading to increased plant productivity. It is also known that applications of biochar to soilless potting substrates and to soil increases resistance of plants against diseases, but also bear the potential to have inconsistent and contradictory results depending on the type of biochar feedstock and application rate. The following study examined the effect of biochar produced from maple bark on soybean resistance against Rhizoctonia foliar blight (RFB) disease caused by Rhizoctonia solani, and examined the underlying molecular responses of both soybean and R. solani during interaction with biochar application. Soybean plants were grown in the presence of 1, 3, or 5% (w/w) or absence of maple bark biochar for 2 weeks, and leaves were infected with R. solani AG1-IA. At lower concentrations (1 and 3%), biochar was ineffective against RFB, however at the 5% amendment rate, biochar was conducive to RFB with a significant increase in disease severity. For the first time, soybean and R. solani responsive genes were monitored during the development of RFB on detached leaves of plants grown in the absence and presence of 5% biochar at 0, 6, 12, and 24 h post-inoculation (h.p.i.). Generally, large decreases in soybean transcript abundances of genes associated with primary metabolism such as glycolysis, tricarboxylic acid (TCA) cycle, starch, amino acid and glutathione metabolism together with genes associated with plant defense and immunity such as salicylic acid (SA) and jasmonic acid pathways were observed after exposure of soybean to high concentration of biochar. Such genes are critical for plant protection against biotic and abiotic stresses. The general down-regulation of soybean genes and changes in SA hormonal balance were tightly linked with an increased susceptibility to RFB. In conjunction, R. solani genes associated

  18. Biochar Amendment Modifies Expression of Soybean and Rhizoctonia solani Genes Leading to Increased Severity of Rhizoctonia Foliar Blight

    PubMed Central

    Copley, Tanya; Bayen, Stéphane; Jabaji, Suha

    2017-01-01

    Application of biochar, a pyrolyzed biomass from organic sources, to agricultural soils is considered a promising strategy to sustain soil fertility leading to increased plant productivity. It is also known that applications of biochar to soilless potting substrates and to soil increases resistance of plants against diseases, but also bear the potential to have inconsistent and contradictory results depending on the type of biochar feedstock and application rate. The following study examined the effect of biochar produced from maple bark on soybean resistance against Rhizoctonia foliar blight (RFB) disease caused by Rhizoctonia solani, and examined the underlying molecular responses of both soybean and R. solani during interaction with biochar application. Soybean plants were grown in the presence of 1, 3, or 5% (w/w) or absence of maple bark biochar for 2 weeks, and leaves were infected with R. solani AG1-IA. At lower concentrations (1 and 3%), biochar was ineffective against RFB, however at the 5% amendment rate, biochar was conducive to RFB with a significant increase in disease severity. For the first time, soybean and R. solani responsive genes were monitored during the development of RFB on detached leaves of plants grown in the absence and presence of 5% biochar at 0, 6, 12, and 24 h post-inoculation (h.p.i.). Generally, large decreases in soybean transcript abundances of genes associated with primary metabolism such as glycolysis, tricarboxylic acid (TCA) cycle, starch, amino acid and glutathione metabolism together with genes associated with plant defense and immunity such as salicylic acid (SA) and jasmonic acid pathways were observed after exposure of soybean to high concentration of biochar. Such genes are critical for plant protection against biotic and abiotic stresses. The general down-regulation of soybean genes and changes in SA hormonal balance were tightly linked with an increased susceptibility to RFB. In conjunction, R. solani genes associated

  19. Quantification of rice sheath blight progression caused by Rhizoctonia solani.

    PubMed

    Su'udi, Mukhamad; Park, Jong-Mi; Kang, Woo-Ri; Hwang, Duk-Ju; Kim, Soonok; Ahn, Il-Pyung

    2013-06-01

    Rhizoctonia solani has a wide host range, including almost all cultivated crops and its subgroup anastomosis group (AG)-1 IA causes sheath blight in rice. An accurate measurement of pathogen's biomass is a convincing tool for enumeration of this disease. Mycological characteristics and molecular diagnosis simultaneously supported that all six strains in this study were R. solani AG-1 IA. Heterokaryons between strains Rs40104, Rs40105, and Rs45811 were stable and viable, whereas Rs40103 and Rs40106 did not form viable fused cells, except for the combination of Rs40106 and Rs40104. A primer pair was highly specific to RsAROM gene of R. solani strains and the amplified fragment exists as double copies within fungal genome. The relationship between crossing point (CP) values and the amount of fungal DNA was reliable (R (2) >0.99). Based on these results, we determined R. solani's proliferation within infected stems through real time PCR using a primer pair and a Taqman probe specific to the RsAROM gene. The amount of fungal DNA within the 250 ng of tissue DNA from rice cv. Dongjin infected with Rs40104, Rs40105, and Rs45811 were 7.436, 5.830, and 5.085 ng, respectively. In contrast, the fungal DNAs within the stems inoculated with Rs40103 and Rs40106 were 0.091 and 0.842 ng. The sheath blight symptom progression approximately coincided with the amount of fungal DNA within the symptoms. In summary, our quantitative evaluation method provided reliable and objective results reflecting the amount of fungal biomass within the infected tissues and would be useful for evaluation of resistance germplasm or fungicides and estimation of inoculum potential.

  20. Azomethine based nano-chemicals: Development, in vitro and in vivo fungicidal evaluation against Sclerotium rolfsii, Rhizoctonia bataticola and Rhizoctonia solani.

    PubMed

    Mondal, Prithusayak; Kumar, Rajesh; Gogoi, Robin

    2017-02-01

    Fungal diseases posing a severe threat to the production of pulses, a major protein source, necessitates the need of new highly efficient antifungal agents. The present study was aimed to develop azomethine based nano-fungicides for protecting the crop from fungal pathogens and subsequent yield losses. The protocol for the formation of nano-azomethines was generated and standardized. Technically pure azomethines were transformed into their nano-forms exploiting polyethylene glycol as the surface stabilizer. Characterization was performed by optical (imaging) probe (Zetasizer) and electron probe (TEM) characterization techniques. The mean particle sizes of all nano-fungicides were below 100nm. In vitro fungicidal potential of nano-chemicals was increased by 2 times in comparison to that of conventional sized azomethines against pathogenic fungi, namely, Rhizoctonia solani, Rhizoctonia bataticola and Sclerotium rolfsii. The performance of nano-chemicals in pot experiment study was also superior to conventional ones as antifungal agent.

  1. Chemical and Hot Water Treatments to Control Rhizoctonia on Infected Azalea Stem Cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spring shoot growth of azalea 'Gumpo White' used for propagation of stem cuttings can harbor binucleate Rhizoctonia species that cause web blight, thus the pathogen is unsuspectingly propagated with the plant. The objective of this study was to evaluate efficacy of disinfesting methods (commercially...

  2. nalyses of rhizoctonia screening nursery results over 15 selected years from 1980 to 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA-ARS has had a research program at Fort Collins focused on breeding for resistance to Rhizoctonia crown and root rot (Rcrr) since the late 1950s. By 1980, current resistant and susceptible checks were in use. All individual roots from each plot were lifted and rated on a disease index (DI)...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. Geographic distribution of Rhizoctonia and Pythium species in soils throughout eastern Washington.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia and Pythium species cause substantial reductions in yield in eastern Washington. Both organisms are common in agricultural soils; however, the specific species or anastomosis group (AG) present can vary from site to site. Due to a wide range in virulence among these different groups, t...

  10. 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...

  11. 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...

  12. Rhizoctonia crown and root rot resistance evaluation of Beta PIs in Fort Collins, CO, 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-six sugar beet (Beta vulgaris subsp. vulgaris) germplasm from the USDA-Agricultural Research Service pre-breeding program at Fort Collins, Colorado were screened for resistance to Rhizoctonia crown and root rot (RCRR) at the Colorado State University ARDEC facility in Fort Collins, CO. There...

  13. 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...

  14. 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...

  15. Molecular characterization, morphological characteristics, virulence and geographic distribution of Rhizoctonia spp. in Washington State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia root rot and bare patch, caused by R. solani AG-8 and R. oryzae, are chronic and important yield-limiting diseases of wheat and barley in the Inland Pacific Northwest (PNW) of the USA. Major gaps remain in our understanding of the epidemiology of these diseases, and because multiple Rhiz...

  16. 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 ...

  17. Screening of pea genotypes for resistance to root rot caused by Rhizoctonia solani AG 8, 2012.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 8 is one of the major pathogens that causes pea root rot and stunting in the Columbia Basin of Oregon and Washington. The disease is most severe in fields where wheat has been mono-cropped for a number of years or where cereal cover crops are incorporated just before pea seedin...

  18. Rhizoctonia crown and root rot resistance evaluation of Beta PIs in Fort Collins, CO, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty beet accessions of either cultivated beet or sea beet (Beta vulgaris subsp. vulgaris or Beta vulgaris subsp. maritima (L.) Arcang) from the Beta collection of the USDA-Agricultural Research Service National Plant Germplasm System were screened for resistance to Rhizoctonia crown and root rot ...

  19. Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 35 onion genotypes was evaluated for resistance to onion stunting caused by Rhizoctonia solani anastomosis group 8 (AG-8) under temperature-controlled greenhouse conditions (15 ± 1oC) in 2013. Each onion genotype was planted in a cone-tainer with and without inoculation with R. solani AG ...

  20. 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...

  1. Rhizoctonia web blight development on azalea in relation to leaf wetness duration in the glasshouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In field trials done in nurseries, temperature was identified as the primary variable for predicting web blight development, caused by binucleate Rhizoctonia spp., on container-grown azaleas (Rhododendron spp.). Moisture, in the form of very low vapor pressure deficits, provided only a minor predict...

  2. 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...

  3. 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...

  4. Bi-fluorescence imaging for estimating accurately the nuclear condition of Rhizoctonia spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To simplify the determination of the nuclear condition of the pathogenic Rhizoctonia, which currently needs to be performed either using two fluorescent dyes, thus is more costly and time-consuming, or using only one fluorescent dye, and thus less accurate. Methods and Results: A red primary ...

  5. Molecular identification, genetic diversity, population genetics, and genomics of Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The basidiomycetous soilborne fungus Rhizoctonia (sensu lato) is an economically important pathogen of worldwide distribution and it is known to attack at least 188 species of higher plants, including agronomic crops, vegetables, ornamentals, forest trees and turfgrasses. The pathogenic isolates may...

  6. 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...

  7. Molecular Characterization, Morphological Characteristics, Virulence, and Geographic Distribution of Rhizoctonia spp. in Washington State.

    PubMed

    Jaaffar, Ahmad Kamil Mohd; Paulitz, Timothy C; Schroeder, Kurtis L; Thomashow, Linda S; Weller, David M

    2016-05-01

    Rhizoctonia root rot and bare patch, caused by Rhizoctonia solani anastomosis group (AG)-8 and R. oryzae, are chronic and important yield-limiting diseases of wheat and barley in the Inland Pacific Northwest (PNW) of the United States. Major gaps remain in our understanding of the epidemiology of these diseases, in part because multiple Rhizoctonia AGs and species can be isolated from the same cereal roots from the field, contributing to the challenge of identifying the causal agents correctly. In this study, a collection totaling 498 isolates of Rhizoctonia was assembled from surveys conducted from 2000 to 2009, 2010, and 2011 over a wide range of cereal production fields throughout Washington State in the PNW. To determine the identity of the isolates, PCR with AG- or species-specific primers and/or DNA sequence analysis of the internal transcribed spacers was performed. R. solani AG-2-1, AG-8, AG-10, AG-3, AG-4, and AG-11 comprised 157 (32%), 70 (14%), 21 (4%), 20 (4%), 1 (0.2%), and 1 (0.2%), respectively, of the total isolates. AG-I-like binucleate Rhizoctonia sp. comprised 44 (9%) of the total; and 53 (11%), 80 (16%), and 51 (10%) were identified as R. oryzae genotypes I, II, and III, respectively. Isolates of AG-2-1, the dominant Rhizoctonia, occurred in all six agronomic zones defined by annual precipitation and temperature within the region sampled. Isolates of AG-8 also were cosmopolitan in their distribution but the frequency of isolation varied among years, and they were most abundant in zones of low and moderate precipitation. R. oryzae was cosmopolitan, and collectively the three genotypes comprised 37% of the isolates. Only isolates of R. solani AG-8 and R. oryzae genotypes II and III (but not genotype I) caused symptoms typically associated with Rhizoctonia root rot and bare patch of wheat. Isolates of AG-2-1 caused only mild root rot and AG-I-like binucleate isolates and members of groups AG-3, AG-4, and AG-11 showed only slight or no discoloration

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

    PubMed

    Amaradasa, B S; Horvath, B J; Lakshman, D K; Warnke, S E

    2013-01-01

    Rhizoctonia blight is a common and serious disease of many turfgrass species. The most widespread causal agent, Thanatephorus cucumeris (anamorph: R. solani), consists of several genetically different subpopulations. In addition, Waitea circinata varieties zeae, oryzae and circinata (anamorph: Rhizoctonia spp.) also can cause the disease. Accurate identification of the causal pathogen is important for effective management of the disease. It is challenging to distinguish the specific causal pathogen based on disease symptoms or macroscopic and microscopic morphology. Traditional methods such as anastomosis reactions with tester isolates are time consuming and sometimes difficult to interpret. In the present study universally primed PCR (UP-PCR) fingerprinting was used to assess genetic diversity of Rhizoctonia spp. infecting turfgrasses. Eighty-four Rhizoctonia isolates were sampled from diseased turfgrass leaves from seven distinct geographic areas in Virginia and Maryland. Rhizoctonia isolates were characterized by ribosomal DNA internal transcribed spacer (rDNA-ITS) region and UP-PCR. The isolates formed seven clusters based on ITS sequences analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering of UP-PCR markers, which corresponded well with anastomosis groups (AGs) of the isolates. Isolates of R. solani AG 1-IB (n = 18), AG 2-2IIIB (n = 30) and AG 5 (n = 1) clustered separately. Waitea circinata var. zeae (n = 9) and var. circinata (n = 4) grouped separately. A cluster of six isolates of Waitea (UWC) did not fall into any known Waitea variety. The binucleate Rhizoctonia-like fungi (BNR) (n = 16) clustered into two groups. Rhizoctonia solani AG 2-2IIIB was the most dominant pathogen in this study, followed by AG 1-IB. There was no relationship between the geographic origin of the isolates and clustering of isolates based on the genetic associations. To our knowledge this is the first time UP-PCR was used to characterize Rhizoctonia

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

    PubMed

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

    2015-03-01

    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.

  10. 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

  11. 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.

  12. Maple Bark Biochar Affects Rhizoctonia solani Metabolism and Increases Damping-Off Severity.

    PubMed

    Copley, Tanya R; Aliferis, Konstantinos A; Jabaji, Suha

    2015-10-01

    Many studies have investigated the effect of biochar on plant yield, nutrient uptake, and soil microbial populations; however, little work has been done on its effect on soilborne plant diseases. To determine the effect of maple bark biochar on Rhizoctonia damping-off, 11 plant species were grown in a soilless potting substrate amended with different concentrations of biochar and inoculated or not with Rhizoctonia solani anastomosis group 4. Additionally, the effect of biochar amendment on R. solani growth and metabolism in vitro was evaluated. Increasing concentrations of maple bark biochar increased Rhizoctonia damping-off of all 11 plant species. Using multivariate analyses, we observed positive correlations between biochar amendments, disease severity and incidence, abundance of culturable bacterial communities, and physicochemical parameters. Additionally, biochar amendment significantly increased R. solani growth and hyphal extension in vitro, and altered its primary metabolism, notably the mannitol and tricarboxylic acid cycles and the glycolysis pathway. One or several organic compounds present in the biochar, as identified by gas chromatography-mass spectrometry analysis, may be metabolized by R. solani. Taken together, these results indicate that future studies on biochar should focus on the effect of its use as an amendment on soilborne plant pathogens before applying it to soils.

  13. Timing of fungicides in relation to calendar date, weather, and disease thresholds to control Rhizoctonia web blight 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. Fungicides are the only practical control method, but a guideline for timing of fungicides is not available....

  14. Molecular characterisation of an endornavirus from Rhizoctonia solani AG-3PT infecting potato.

    PubMed

    Das, Subha; Falloon, Richard E; Stewart, Alison; Pitman, Andrew R

    2014-11-01

    Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a soil-borne plant pathogenic fungus that has a broad host range, including potato. In this study, the double-stranded RNA (dsRNA) profiles were defined for 39 Rhizoctonia solani isolates representative of two different anastomosis groups (AGs) associated with black scurf of potato in New Zealand. A large dsRNA of c. 12 kb-18 kb was detected in each of the isolates, regardless of AG or virulence on potato. Characterisation of the large dsRNA from R. solani AG-3PT isolate RS002, using random amplification of total dsRNA and analyses of overlapping cDNA sequences, resulted in the assembly of a consensus sequence of 14 694 nt. A single, large open reading frame was identified on the positive strand of the assembled sequence encoding a putative polypeptide of at least 4893 amino acids, with a predicted molecular mass of 555.6 kDa. Conserved domains within this polypeptide included those for a viral methyltransferase, a viral RNA helicase 1 and an RNA-dependent RNA polymerase. The domains and their sequential organisation revealed the polyprotein was very similar to those encoded by dsRNA viruses of the genus Endornavirus, in the family Endornaviridae. This is the first report of an endornavirus in R. solani, and thus the putative virus is herein named Rhizoctonia solani endornavirus - RS002 (RsEV-RS002). Partial characterisation of the large dsRNAs in five additional AG-3PT isolates of R. solani also identified them as probable endornaviruses, suggesting this family of viruses is widespread in R. solani infecting potato. The ubiquitous nature of endornaviruses in this plant pathogen implies they may have an important, but yet uncharacterised, role in R. solani.

  15. Cropping systems and cultural practices determine the Rhizoctonia anastomosis groups associated with Brassica spp. in Vietnam.

    PubMed

    Hua, Gia Khuong Hoang; Bertier, Lien; 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.

  16. 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

  17. Leuconostoc spp. Associated with Root Rot in Sugar Beet and Their Interaction with Rhizoctonia solani.

    PubMed

    Strausbaugh, Carl A

    2016-05-01

    Rhizoctonia root and crown rot is an important disease problem in sugar beet caused by Rhizoctonia solani and also shown to be associated with Leuconostoc spp. Initial Leuconostoc studies were conducted with only a few isolates and the relationship of Leuconostoc with R. solani is poorly understood; therefore, a more thorough investigation was conducted. In total, 203 Leuconostoc isolates were collected from recently harvested sugar beet roots in southern Idaho and southeastern Oregon during 2010 and 2012: 88 and 85% Leuconostoc mesenteroides, 6 and 15% L. pseudomesenteroides, 2 and 0% L. kimchi, and 4 and 0% unrecognized Leuconostoc spp., respectively. Based on 16S ribosomal RNA sequencing, haplotype 11 (L. mesenteroides isolates) comprised 68 to 70% of the isolates in both years. In pathogenicity field studies with commercial sugar beet 'B-7', all Leuconostoc isolates caused more rot (P < 0.0001; α = 0.05) when combined with R. solani than when inoculated alone in both years. Also, 46 of the 52 combination treatments over the 2 years had significantly more rot (P < 0.0001; α = 0.05) than the fungal check. The data support the conclusion that a synergistic interaction leads to more rot when both Leuconostoc spp. and R. solani are present in sugar beet roots.

  18. Interaction of Pratylenchus penetrans and Rhizoctonia fragariae in Strawberry Black Root Rot

    PubMed Central

    LaMondia, J. A.

    2003-01-01

    A split-root technique was used to examine the interaction between Pratylenchus penetrans and the cortical root-rotting pathogen Rhizoctonia fragariae in strawberry black root rot. Plants inoculated with both pathogens on the same half of a split-root crown had greater levels of root rot than plants inoculated separately or with either pathogen alone. Isolation of R. fragariae from field-grown roots differed with root type and time of sampling. Fungal infection of structural roots was low until fruiting, whereas perennial root colonization was high. Isolation of R. fragariae from feeder roots was variable, but was greater from feeder roots on perennial than from structural roots. Isolation of the fungus was greater from structural roots with nematode lesions than from non-symptomatic roots. Rhizoctonia fragariae was a common resident on the sloughed cortex of healthy perennial roots. From this source, the fungus may infect additional roots. The direct effects of lesion nematode feeding and movement are cortical cell damage and death. Indirect effects include discoloration of the endodermis and early polyderm formation. Perhaps weakened or dying cells caused directly or indirectly by P. penetrans are more susceptible to R. fragariae, leading to increased disease. PMID:19265969

  19. 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...

  20. Identity and specificity of Rhizoctonia-like fungi from different populations of Liparis japonica (Orchidaceae) in Northeast China.

    PubMed

    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.

  1. 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

  2. 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-...

  3. USDA-ARS germplasm evaluated for resistance to Rhizoctonia crown and root rot in Fort Collins, CO, 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-six sugar beet (Beta vulgaris subsp. vulgaris) germplasm from the USDA-Agricultural Research Service pre-breeding program at Fort Collins, Colorado were screened for resistance to Rhizoctonia crown and root rot (RCRR) at the Colorado State University ARDEC facility in Fort Collins, CO. There...

  4. Sugar beet breeding lines evaluated for resistance to Rhizoctonia crown and root rot in Fort Collins, CO, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-nine beet sugar beet breeding lines (Beta vulgaris subsp. vulgaris) from the USDA-Agricultural Research Service breeding program at Fort Collins, CO, were screened for resistance to Rhizoctonia crown and root rot (Rcrr) at the Colorado State University ARDEC facility in Fort Collins, CO. The...

  5. Use of the polymerase chain reaction to help determine the presence of blackpatch (Rhizoctonia leguminicola) in inoculated red clover leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia leguminicola, the causal agent of blackpatch of red clover, produces alkaloids that cause livestock to salivate excessively. Its presence is generally confirmed by microscopy, disappearance of symptoms after removal of the suspect forage, and chromatographic analysis of slaframine in ext...

  6. 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 ...

  7. Isolates of Rhizoctonia solani can produce both web blight and root rot symptoms in common bean (Phaseolus vulgaris L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani Kühn (Rs) is an important pathogen in the tropics, causing web blight (WB), and a widespread soil-borne root rot (RR) pathogen of common bean (Phaseolus vulgaris L.) worldwide. This pathogen is a species complex classified into 14 anastomosis groups (AG). Some AGs have been report...

  8. 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...

  9. Blackpatch of clover, cause of slobbers syndrome: A review of the disease and the pathogen, Rhizoctonia leguminicola

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia leguminicola Gough and E.S. Elliott is a widely used name for the causal agent of blackpatch disease of red clover (Trifolium pratense L.), which infects other legumes as well. This fungal pathogen produces alkaloids (slaframine and swainsonine) that affect grazing mammals. Slaframine ca...

  10. Spread potential of binucleate Rhizoctonia from nursery propagation floors to trays containing azalea stem cuttings and sanitary control options

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Binucelate Rhizoctonia sp. (BNR), the cause of web blight, can be spread on azalea stem cuttings into propagation houses, but can be eliminated from stems by submerging cuttings in 50°C water for 21 minutes. The overall objective was to evaluate risk of rooting cuttings in trays becoming contaminate...

  11. 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...

  12. 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

  13. Screening of bioagents against root rot of mung bean caused by Rhizoctonia solani.

    PubMed

    Singh, S; Chand, H

    2006-01-01

    A laboratory and green house experiment was carried out on the comparative antagonistic performance of four different bioagents (Aspergillus sp., Gliocladium virens, Trichoderma harzianum and T. viride) isolated from soil against Rhizoctonia solani. Under laboratory conditions, T. harzianum exhibited maximum (75.55%) mycelial growth inhibition of R. solani This was followed by T. viride, which showed 65.93 per cent mycelial growth inhibition of the pathogen. Gliocladium virens was also found to be effective antagonists, which exhibited 57.77 per cent mycelial growth inhibition. While Aspergillus sp exhibited minimum growth inhibition (45.74%) in comparison to other bioagents. Under green house conditions, T. harzianum gave maximum protection of the disease (72.72%) followed by T. viride, which exhibited 54.54 per cent disease control. However, G. virens and Aspergillus sp were found least effective in controlling root rot of mungbean.

  14. Screening of bioagents against root rot of mung bean caused by Rhizoctonia solani.

    PubMed

    Singh, Surender; Chand, Hari

    2006-01-01

    A laboratory and green house experiment was carried out on the comparative antagonistic performance of four different bioagents (Aspergillus sp. Gliocladium virens, Trichoderma harzianum and T. viride) isolated from soil against Rhizoctonia solani. Under laboratory conditions, T. harzianum exhibited maximum (75.55%) mycelial growth inhibition of R. solani. This was followed by T. viride, which showed 65.93% mycelial growth inhibition of the pathogen. Gliocladium virens was also found to be effective antagonists, which exhibited 57.77% mycelial growth inhibition. While Aspergillus sp exhibited minimum growth inhibition (45.74%) in comparison to other bioagents. Under green house conditions, T. harzianum gave maximum protection of the disease (72.72%) followed by T. viride, which exhibited 54.54% disease control. However, G. virens and Aspergillus sp were found least effective in controlling root rot of mungbean.

  15. Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

    PubMed

    Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

    2014-01-01

    Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.

  16. Effects of the herbicides fluometuron and prometryn of Rhizoctonia solani in soil cultures.

    PubMed

    Beam, H W; Curl, E A; Rodriguez-Kabana, R

    1977-05-01

    Responses of Rhizoctonia solani to herbicides in soil cultures were assessed by measuring soil enzyme activity and other growth-related factors. Both beta-galactosidase (EC 3.2.1.23) and phosphatase (EC 3.1.3.1.3.1.3.2) activities were highly correlated with amounts of mycelium in soil. Both enzyme activities were reduced significantly by either fluometuron or prometryn at 40 microgram/g of soil; the pathogen was more distinctly suppressed by fluometron and showed a stronger tendency to overcome the effects of prometryn with time. Inhibition was also reflected in reduced ultilization of glucose and less CO2-C evolved. Except for an increase in beta-galactosidase activity in the presence of 1 microgram fluometuron, low levels of either herbicide had little effect on the pathogen.

  17. 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.

  18. Biocontrol efficacy of different isolates of Trichoderma against soil borne pathogen Rhizoctonia solani.

    PubMed

    Asad, Saeed Ahmad; Ali, Naeem; Hameed, Abdul; Khan, Sabaz Ali; Ahmad, Rafiq; Bilal, Muhammad; Shahzad, Muhammad; Tabassum, Ayesha

    2014-01-01

    In this study, the biocontrol abilities of water-soluble and volatile metabolites of three different isolates of Trichoderma (T. asperellum, T. harzianum and Trichoderma spp.) against soil borne plant pathogen Rhizoctonia solani were investigated both in vitro and in vivo. The results showed for the first time that mycelial growth inhibition of the pathogen was 74.4-67.8% with water-soluble metabolites as compared to 15.3-10.6% with volatile metabolites in vitro. In vivo antagonistic activity of Trichoderma isolates against R. solani was evaluated on bean plants under laboratory and greenhouse conditions. We observed that T. asperellum was more effective and consistent, lowering disease incidence up to 19.3% in laboratory and 30.5% in green house conditions. These results showed that three isolates of Trichoderma could be used as effective biocontrol agents against R. solani.

  19. Antifungal effect and mechanism of chitosan against the rice sheath blight pathogen, Rhizoctonia solani.

    PubMed

    Liu, He; Tian, Wenxiao; Li, Bin; Wu, Guoxing; Ibrahim, Muhammad; Tao, Zhongyun; Wang, Yangli; Xie, Guanlin; Li, Hongye; Sun, Guochang

    2012-12-01

    The antifungal properties and mechanism of three types of chitosan against the rice sheath blight pathogen, Rhizoctonia solani, were evaluated. Each chitosan had strong antifungal activity against R. solani and protected rice seedlings from sheath blight, in particular, two types of acid-soluble chitosan caused a 60-91 % inhibition in mycelial growth, 31-84 % inhibition of disease incidence, and 66-91 % inhibition in lesion length. The mechanism of chitosan in protection of rice from R. solani pathogen was attributed to direct destruction of the mycelium, evidenced by scanning and transmission electron microscopic observations and pathogenicity testing; indirect induced resistance was evidenced by the changes in the activities of the defense-related phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in rice seedling. To our knowledge, this is the first report on the antifungal activity of chitosan against rice R. solani.

  20. Genome sequence of a novel mycovirus of Rhizoctonia solani, a plant pathogenic fungus.

    PubMed

    Zhong, Jie; Chen, Chuan-Yuan; Gao, Bi-Da

    2015-08-01

    Here we present the genome sequence of a novel dsRNA virus we designed as Rhizoctonia solani RNA virus HN008 (RsRV-HN008) from a filamentous fungus R. solani. Its genome (7596 nucleotides) contains two non-overlapping open reading frames (ORF1 and ORF2). ORF1 encoded a 128 kDa protein that showed no significant identity to any other virus sequence in the NCBI database. ORF2 encoded a protein with a molecular weight of 140 kDa and shared a low percentage of sequence identity to the RdRps of unclassified dsRNA viruses. Sequence analysis revealed that RsRV-HN008 may be a member of a novel unclassified family of mycoviruses.

  1. Alterations in rice chloroplast integrity, photosynthesis and metabolome associated with pathogenesis of Rhizoctonia solani

    PubMed Central

    Ghosh, Srayan; Kanwar, Poonam; Jha, Gopaljee

    2017-01-01

    Sheath blight disease is caused by a necrotrophic fungal pathogen Rhizoctonia solani and it continues to be a challenge for sustainable rice cultivation. In this study, we adopted a multi-pronged approach to understand the intricacies of rice undergoing susceptible interactions with R. solani. Extensive anatomical alteration, chloroplast localized ROS, deformed chloroplast ultrastructure along with decreased photosynthetic efficiency were observed in infected tissue. GC-MS based metabolite profiling revealed accumulation of glycolysis and TCA cycle intermediates, suggesting enhanced respiration. Several aromatic and aliphatic amino acids along with phenylpropanoid intermediates were also accumulated, suggesting induction of secondary metabolism during pathogenesis. Furthermore, alterations in carbon metabolism along with perturbation of hormonal signalling were highlighted in this study. The gene expression analysis including RNAseq profiling reinforced observed metabolic alterations in the infected tissues. In conclusion, the present study unravels key events associated during susceptible rice-R. solani interactions and identifies metabolites and transcripts that are accumulated in infected tissues. PMID:28165003

  2. Characterization and colonization of endomycorrhizal Rhizoctonia fungi in the medicinal herb Anoectochilus formosanus (Orchidaceae).

    PubMed

    Jiang, Jr-Hau; Lee, Yung-I; Cubeta, Marc A; Chen, Lung-Chung

    2015-08-01

    The medicinal effects and techniques for cultivating Anoectochilus formosanus are well-documented, but little is known about the mycorrhizal fungi associated with A. formosanus. Rhizoctonia (Thanatephorus) anastomosis group 6 (AG-6) was the most common species isolated from fungal pelotons in native A. formosanus and represented 67% of the sample. Rhizoctonia (Ceratobasidium) AG-G, P, and R were also isolated and represent the first occurrence in the Orchidaceae. Isolates of AG-6, AG-R, and AG-P in clade I increased seed germination 44-91% and promoted protocorm growth from phases III to VI compared to asymbiotic treatments and isolates of AG-G in clade II and Tulasnella species in clade III. All isolates in clades I to III formed fungal pelotons in tissue-cultured seedlings of A. formosanus, which exhibited significantly greater growth than nonmycorrhizal seedlings. An analysis of the relative effect of treatment ([Formula: see text]) showed that the low level of colonization ([Formula: see text]) by isolates in clade I resulted in a significant increase in seedling growth compared to isolates in clades II (0.63-0.82) and III (0.63-0.75). There was also a negative correlation (r = -0.8801) with fresh plant weight and fungal colonization. Our results suggest that isolates in clade I may represent an important group associated with native populations of A. formosanus and can vary in their ability to establish a symbiotic association with A. formosanus. The results presented here are potentially useful for advancing research on the medicinal properties, production, and conservation of A. formosanus in diverse ecosystems.

  3. Identification and functional analysis of AG1-IA specific genes of Rhizoctonia solani.

    PubMed

    Ghosh, Srayan; Gupta, Santosh Kumar; Jha, Gopaljee

    2014-11-01

    Rhizoctonia solani is an important necrotrophic fungal pathogen which causes disease on diverse plant species. It has been classified into 14 genetically distinct anastomosis groups (AGs), however, very little is known about their genomic diversity. AG1-IA causes sheath blight disease in rice and controlling this disease remains a challenge for sustainable rice cultivation. Recently the draft genome sequences of AG1-IA (rice isolate) and AG1-IB (lettuce isolate) had become publicly available. In this study, using comparative genomics, we report identification of 3,942 R. solani genes that are uniquely present in AG1-IA. Many of these genes encode important biological, molecular functions and exhibit dynamic expression during in-planta growth of the pathogen in rice. Based upon sequence similarity with genes that are required for plant and human/zoonotic diseases, we identified several putative virulence/pathogenicity determinants amongst AG1-IA specific genes. While studying the expression of 19 randomly selected genes, we identified three genes highly up-regulated during in-planta growth. The detailed in silico characterization of these genes and extent of their up-regulation in different rice genotypes, having variable degree of disease susceptibility, suggests their importance in rice-Rhizoctonia interactions. In summary, the present study reports identification, functional characterization of AG1-IA specific genes and predicts important virulence determinants that might enable the pathogen to grow inside hostile plant environment. Further characterization of these genes would shed useful insights about the pathogenicity mechanism of AG1-IA on rice.

  4. Postharvest dark skin spots in potato tubers are an oversuberization response to Rhizoctonia solani infection.

    PubMed

    Buskila, Yossi; Tsror Lahkim, Leah; Sharon, Michal; Teper-Bamnolker, Paula; Holczer-Erlich, Orly; Warshavsky, Shimon; Ginzberg, Idit; Burdman, Saul; Eshel, Dani

    2011-04-01

    Israeli farmers export 250,000 tons of potato tubers annually, ≈40,000 tons of which are harvested early, before skin set. In recent years, there has been an increase in the occurrence of dark skin spots on early-harvested potato tubers ('Nicola') packed in large bags containing peat to retain moisture. The irregular necrotic spots form during storage and overseas transport. Characterization of the conditions required for symptom development indicated that bag temperature after packing is 11 to 13°C and it reaches the target temperature (8°C) only 25 days postharvest. This slow decrease in temperature may promote the establishment of pathogen infection. Isolates from typical lesions were identified as Rhizoctonia spp., and Koch's postulates were completed with 25 isolates by artificial inoculation performed at 13 to 14°C. Phylogenetic analysis, using the internal transcribed spacer sequences (ITS1 and ITS2) of rDNA genes, assigned three isolates to anastomosis group 3 of Rhizoctonia solani. Inoculation of wounded tubers with mycelium of these R. solani isolates resulted in an oversuberization response in the infected area. With isolate Rh17 of R. solani, expression of the suberin biosynthesis-related genes StKCS6 and CYP86A33 increased 6.8- and 3.4-fold, respectively, 24 h postinoculation, followed by a 2.9-fold increase in POP_A, a gene associated with wound-induced suberization, expression 48 h postinoculation, compared with the noninoculated tubers. We suggest that postharvest dark spot disease is an oversuberization response to R. solani of AG-3 infection that occurs prior to tuber skin set.

  5. Wide variation in virulence and genetic diversity of binucleate Rhizoctonia isolates associated with root rot of strawberry in Western Australia.

    PubMed

    Fang, Xiangling; Finnegan, Patrick M; Barbetti, Martin J

    2013-01-01

    Strawberry (Fragaria×ananassa) is one of the most important berry crops in the world. Root rot of strawberry caused by Rhizoctonia spp. is a serious threat to commercial strawberry production worldwide. However, there is no information on the genetic diversity and phylogenetic status of Rhizoctonia spp. associated with root rot of strawberry in Australia. To address this, a total of 96 Rhizoctonia spp. isolates recovered from diseased strawberry plants in Western Australia were characterized for their nuclear condition, virulence, genetic diversity and phylogenetic status. All the isolates were found to be binucleate Rhizoctonia (BNR). Sixty-five of the 96 BNR isolates were pathogenic on strawberry, but with wide variation in virulence, with 25 isolates having high virulence. Sequence analysis of the internal transcribed spacers of the ribosomal DNA separated the 65 pathogenic BNR isolates into six distinct clades. The sequence analysis also separated reference BNR isolates from strawberry or other crops across the world into clades that correspond to their respective anastomosis group (AG). Some of the pathogenic BNR isolates from this study were embedded in the clades for AG-A, AG-K and AG-I, while other isolates formed clades that were sister to the clades specific for AG-G, AG-B, AG-I and AG-C. There was no significant association between genetic diversity and virulence of these BNR isolates. This study demonstrates that pathogenic BNR isolates associated with root rot of strawberry in Western Australia have wide genetic diversity, and highlights new genetic groups not previously found to be associated with root rot of strawberry in the world (e.g., AG-B) or in Australia (e.g., AG-G). The wide variation in virulence and genetic diversity identified in this study will be of high value for strawberry breeding programs in selecting, developing and deploying new cultivars with resistance to these multi-genetic groups of BNR.

  6. Draft Genome Sequence of the Plant-Pathogenic Soil Fungus Rhizoctonia solani Anastomosis Group 3 Strain Rhs1AP

    PubMed Central

    Cubeta, Marc A.; Dean, Ralph A.; Jabaji, Suha; Neate, Stephen M.; Tavantzis, Stellos; Toda, Takeshi; Vilgalys, Rytas; Bharathan, Narayanaswamy; Fedorova-Abrams, Natalie; Pakala, Suman B.; Pakala, Suchitra M.; Zafar, Nikhat; Joardar, Vinita; Losada, Liliana; Nierman, William C.

    2014-01-01

    The soil fungus Rhizoctonia solani is a pathogen of agricultural crops. Here, we report on the 51,705,945 bp draft consensus genome sequence of R. solani strain Rhs1AP. A comprehensive understanding of the heterokaryotic genome complexity and organization of R. solani may provide insight into the plant disease ecology and adaptive behavior of the fungus. PMID:25359908

  7. Elucidating the role of the phenylacetic acid metabolic complex in the pathogenic activity of Rhizoctonia solani anastomosis group 3.

    PubMed

    Bartz, Faith E; Glassbrook, Norman J; Danehower, David A; Cubeta, Marc A

    2012-01-01

    The soil fungus Rhizoctonia solani produces phytotoxic phenylacetic acid (PAA) and hydroxy (OH-) and methoxy (MeO-) derivatives of PAA. However, limited information is available on the specific role that these compounds play in the development of Rhizoctonia disease symptoms and concentration(s) required to induce a host response. Reports that PAA inhibits the growth of R. solani conflict with the established ability of the fungus to produce and metabolize PAA. Experiments were conducted to clarify the role of the PAA metabolic complex in Rhizoctonia disease. In this study the concentration of PAA and derivatives required to induce tomato root necrosis and stem canker, in the absence of the fungus, and the concentration that inhibits mycelial growth of R. solani were determined. The effect of exogenous PAA and derivatives of PAA on tomato seedling growth also was investigated. Growth of tomato seedlings in medium containing 0.1-7.5 mM PAA and derivatives induced necrosis of up to 85% of root system. Canker development resulted from injection of tomato seedling stems with 7.5 mM PAA, 3-OH-PAA, or 3-MeO-PAA. PAA in the growth medium reduced R. solani biomass, with 50% reduction observed at 7.5 mM. PAA, and derivatives were quantified from the culture medium of 14 isolates of R. solani belonging to three distinct anastomosis groups by GC-MS. The quantities ranged from below the limit of detection to 678 nM, below the concentrations experimentally determined to be phytotoxic. Correlation analyses revealed that isolates of R. solani that produced high PAA and derivatives in vitro also caused high mortality on tomato seedlings. The results of this investigation add to the body of evidence that the PAA metabolic complex is involved in Rhizoctonia disease development but do not indicate that production of these compounds is the primary or the only determinant of pathogenicity.

  8. Characterizing and Mapping Resistance in Synthetic-Derived Wheat to Rhizoctonia Root Rot in a Green Bridge Environment.

    PubMed

    Mahoney, A K; Babiker, E M; Paulitz, T C; See, D; Okubara, P A; Hulbert, S H

    2016-10-01

    Root rot caused by Rhizoctonia spp. is an economically important soilborne disease of spring-planted wheat in growing regions of the Pacific Northwest (PNW). The main method of controlling the disease currently is through tillage, which deters farmers from adopting the benefits of minimal tillage. Genetic resistance to this disease would provide an economic and environmentally sustainable resource for farmers. In this study, a collection of synthetic-derived genotypes was screened in high-inoculum and low-inoculum field environments. Six genotypes were found to have varying levels of resistance and tolerance to Rhizoctonia root rot. One of the lines, SPBC-3104 ('Vorobey'), exhibited good tolerance in the field and was crossed to susceptible PNW-adapted 'Louise' to examine the inheritance of the trait. A population of 190 BC1-derived recombinant inbred lines was assessed in two field green bridge environments and in soils artificially infested with Rhizoctonia solani AG8. Genotyping by sequencing and composite interval mapping identified three quantitative trait loci (QTL) controlling tolerance. Beneficial alleles of all three QTL were contributed by the synthetic-derived genotype SPCB-3104.

  9. A novel L-amino acid oxidase from Trichoderma harzianum ETS 323 associated with antagonism of Rhizoctonia solani.

    PubMed

    Yang, Chia-Ann; Cheng, Chi-Hua; Lo, Chaur-Tsuen; Liu, Shu-Ying; Lee, Jeng-Woei; Peng, Kou-Cheng

    2011-05-11

    Trichoderma spp. are used as biocontrol agents against phytopathogens such as Rhizoctonia solani, but their biocontrol mechanisms are poorly understood. A novel L-amino oxidase (Th-LAAO) was identified from the extracellular proteins of Trichoderma harzianum ETS 323. Here, we show a FAD-binding glycoprotein with the best substrate specificity constant for L-phenylalanine. Although the amino acid sequence of Th-LAAO revealed limited homology (16-24%) to other LAAO members, a highly conserved FAD-binding motif was identified in the N-terminus. Th-LAAO was shown to be a homodimeric protein, but the monomeric form was predominant when grown in the presence of deactivated Rhizoctonia solani. Furthermore, in vitro assays demonstrated that Th-LAAO had an antagonistic effect against Rhizoctonia solani and a stimulatory one on hyphal density and sporulation in T. harzianum ETS 323. These findings further our understanding of T. harzianum as a biocontrol agent and provide insight into the biological function of l-amino acid oxidase.

  10. Sensitivity of Rhizoctonia Isolates to Phenazine-1-Carboxylic Acid and Biological Control by Phenazine-Producing Pseudomonas spp.

    PubMed

    Jaaffar, Ahmad Kamil Mohd; Parejko, James A; Paulitz, Timothy C; Weller, David M; Thomashow, Linda S

    2017-04-04

    Rhizoctonia solani anastomosis groups (AG)-8 and AG-2-1 and R. oryzae are ubiquitous in cereal-based cropping systems of the Columbia Plateau of the Inland Pacific Northwest and commonly infect wheat. AG-8 and R. oryzae, causal agents of Rhizoctonia root rot and bare patch, are most commonly found in fields in the low-precipitation zone, whereas R. solani AG-2-1 is much less virulent on wheat and is distributed in fields throughout the low-, intermediate-, and high-precipitation zones. Fluorescent Pseudomonas spp. that produce the antibiotic phenazine-1-carboxylic acid (PCA) also are abundant in the rhizosphere of crops grown in the low-precipitation zone but their broader geographic distribution and effect on populations of Rhizoctonia is unknown. To address these questions, we surveyed the distribution of PCA producers (Phz(+)) in 59 fields in cereal-based cropping systems throughout the Columbia Plateau. Phz(+) Pseudomonas spp. were detected in 37 of 59 samples and comprised from 0 to 12.5% of the total culturable heterotrophic aerobic rhizosphere bacteria. The frequency with which individual plants were colonized by Phz(+) pseudomonads ranged from 0 to 100%. High and moderate colonization frequencies of Phz(+) pseudomonads were associated with roots from fields located in the driest areas whereas only moderate and low colonization frequencies were associated with crops where higher annual precipitation occurs. Thus, the geographic distribution of Phz(+) pseudomonads overlaps closely with the distribution of R. solani AG-8 but not with that of R. oryzae or R. solani AG-2-1. Moreover, linear regression analysis demonstrated a highly significant inverse relationship between annual precipitation and the frequency of rhizospheres colonized by Phz(+) pseudomonads. Phz(+) pseudomonads representative of the four major indigenous species (P. aridus, P. cerealis, P. orientalis, and P. synxantha) suppressed Rhizoctonia root rot of wheat when applied as seed treatments. In

  11. 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

  12. Biological control of Rhizoctonia solani on potato by using indigenous Trichoderma spp.

    NASA Astrophysics Data System (ADS)

    Durak, Emre Demirer

    2016-04-01

    At this study, it was aimed to determine the effect of Trichoderma isolates that was isolated from the soil samples taken from the different regions on black scurf and stem canker disease caused by Rhizoctonia solani Kühn that has been one of the biggest problems of the potato cultivation. At the end of the soil isolations, totally 81 Trichoderma isolates were obtained and their species were identified. Of these isolates, T. harzianum (42%), T. virens (31%), T. asperellum (15%) and T. viride (12%). All of the isolates were tested in vitro for their antagonistic activity against the R. solani isolate. The isolates that show high inhibition rate was selected and tested against R. solani in vitro. Potato plants were grown in a greenhouse for about 10 weeks. Then the plants were evaluated according to the scale, plant height, shoot fresh and dry weights, root fresh and dry weights were noted. The experiment was conducted two times in three replications. At the in vitro tests, generally, it was determined that Trichoderma isolates have inhibited to R. solani and in vivo, they were reduced the effects of the disease and they were raised the development of the plant. In particular, it was determined that some isolates of the T. harzianum and T. virens have reduced the severity of the disease. It was determined that both in vitro and in vivo isolates have shown different efficiency against R. solani.

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

    PubMed

    Venu, R C; Jia, Yulin; Gowda, Malali; Jia, Melissa H; Jantasuriyarat, Chatchawan; Stahlberg, Eric; Li, Huameng; Rhineheart, Andrew; Boddhireddy, Prashanth; Singh, Pratibha; Rutger, Neil; Kudrna, David; Wing, Rod; Nelson, James C; Wang, Guo-Liang

    2007-10-01

    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 microarray hybridization. RL-SAGE sequence analysis identified 20,233 and 24,049 distinct tags from the control and inoculated libraries, respectively. Nearly half of the significant tags (> or =2 copies) from both libraries matched TIGR annotated genes and KOME full-length cDNAs. Among them, 42% represented sense and 7% antisense transcripts, respectively. Interestingly, 60% of the library-specific (> or =10 copies) and differentially expressed (>4.0-fold change) tags were novel transcripts matching genomic sequence but not annotated genes. About 70% of the genes identified in the SAGE libraries showed similar expression patterns (up or down-regulated) in the microarray data obtained from three biological replications. Some candidate RL-SAGE tags and microarray genes were located in known sheath blight QTL regions. The expression of ten differentially expressed RL-SAGE tags was confirmed with RT-PCR. The defense genes associated with resistance to R. solani identified in this study are useful genomic materials for further elucidation of the molecular basis of the defense response to R. solani and fine mapping of target sheath blight QTLs.

  14. Proteomic response of Rhizoctonia solani GD118 suppressed by Paenibacillus kribbensis PS04.

    PubMed

    Wang, Liuqing; Liu, Mei; Liao, Meide

    2014-12-01

    Rice sheath blight, caused by Rhizoctonia solani, is considered a worldwide destructive rice disease and leads to considerable yield losses. A bio-control agent, Paenibacillus kribbensis PS04, was screened to resist against the pathogen. The inhibitory effects were investigated (>80 %) by the growth of the hyphae. Microscopic observation of the hypha structure manifested that the morphology of the pathogenic mycelium was strongly affected by P. kribbensis PS04. To explore essentially inhibitory mechanisms, proteomic approach was adopted to identify differentially expressed proteins from R. solani GD118 in response to P. kribbensis PS04 using two-dimensional gel electrophoresis. Protein profiling was used to identify 13 differential proteins: 10 proteins were found to be down-regulated while 3 proteins were up-regulated. These proteins were involved in material and energy metabolism, antioxidant activity, protein folding and degradation, and cytoskeleton regulation. Among them, material and energy metabolism was differentially regulated by P. kribbensis PS04. Protein expression was separately inhibited by the bio-control agent in oxidation resistance, protein folding and degradation, and cytoskeleton regulation. Proteome changes of the mycelium assist in understanding how the pathogen was directly suppressed by P. kribbensis PS04.

  15. Infection with Rhizoctonia solani induces defense genes and systemic resistance in potato sprouts grown without light.

    PubMed

    Lehtonen, M J; Somervuo, P; Valkonen, J P T

    2008-11-01

    Rhizoctonia solani is an important soilborne and seedborne fungal pathogen of potato (Solanum tuberosum). The initial infection of sprouts prior to emergence causes lesions and may be lethal to the sprout or sprout tip, which results in initiation and compensatory growth of new sprouts. They emerge successfully and do not suffer significant damage. The mechanism behind this recovery phenomenon is not known. It was hypothesized that infection may induce pathogen defense in sprouts, which was investigated in the present study. Tubers were sprouted in cool and moist conditions in darkness to mimic conditions beneath soil. The basal portion of the sprout was isolated from the apical portion with a soft plastic collar and inoculated with highly virulent R. solani. Induction of defense-related responses was monitored in the apical portion using microarray and quantitative polymerase chain reaction techniques at 48 and 120 h postinoculation (hpi) and by challenge-inoculation with R. solani in two experiments. Differential expression of 122 and 779 genes, including many well-characterized defense-related genes, was detected at 48 and 120 hpi, respectively. The apical portion of the sprout also expressed resistance which inhibited secondary infection of the sprouts. The observed systemic induction of resistance in sprouts upon infection with virulent R. solani provides novel information about pathogen defense in potato before the plant emerges and becomes photosynthetically active. These results advance our understanding of the little studied subject of pathogen defense in subterranean parts of plants.

  16. The supernatant of Bacillus pumilus SQR-N43 has antifungal activity towards Rhizoctonia solani.

    PubMed

    Huang, Xinqi; Yong, Xiaoyu; Zhang, Ruifu; Shen, Qirong; Yang, Xingming

    2013-08-01

    For clarification of the antagonistic mechanism of Bacillus pumilus SQR-N43 (N43) against Rhizoctonia solani Q1, production of antibiotics by N43 was determined, and the effect of the antibiotics on the pathogen mycelium was microscopically observed. Further more, the control efficiencies of the antifungal compounds on damping-off disease were investigated. The results obtained are listed as follows: N43 produced antibiotic substances towards R. solani Q1 at logarithmic growth phase. The antibiotics caused hyphal deformation and enlargement of cytoplasmic vacuoles in R. solani Q1 mycelia. 70% saturation of ammonium sulfate made a complete precipitation of the antibiotics in culture broth. When treated with protease K and trypsase, the activities of antibiotics were decreased by 79% and 53%, respectively, compared with control. The antibiotics were sensitive to high temperature and were alkaline stable. The molecular weights of the substances were about 500-1000 Da. The bio-control efficiencies of the antibiotics had no significant difference with that of N43 cell suspension. It is a first report that B. pumilus strain produced oligopeptides which had inhibitory effect on R. solani Q1 at logarithmic growth phase.

  17. Efficacy of different fungicides against Rhizoctonia brown patch and Pythium blight on turfgrass in Italy.

    PubMed

    Mocioni, M; Titone, P; Garibaldi, A; Gullino, M L

    2003-01-01

    Brown patch, incited by Rhizoctonia solani Kuhn, and Pythium blight, caused by Pythium spp. are two of the diseases most frequently observed on turfgrass in high maintenance stands, as on golf courses. In such conditions the control strategies, based on chemicals, are particularly difficult due to the scarcity of fungicides registered for turf in Italy. The results obtained in experimental trials carried out to evaluate the efficacy of chemical and biological products against brown patch and Pythium blight are reported. On mature turfgrass, maintained under fairway conditions, azoxystrobin, and trifoxystrobin, not yet registered on turf, were very effective against brown patch. Tebuconazole, applied in three different formulations, was very effective against R. solani, while Trichoderma spp. and azadiractine did not control the pathogen. In greenhouse conditions on Agrostis stolonifera, in the presence of severe disease incidence, due to artificial inoculation, benalaxyl-M satisfactorily controlled Pythium blight; Trichoderma spp. as well as a commercial formulation of T. harzianum, applied one week before the inoculation, were not effective. Among the fungicides not yet registered for use on turfgrass in Italy, metalaxyl-M + mancozeb was effective against Pythium blight.

  18. Expression of a chitinase gene from Metarhizium anisopliae in tobacco plants confers resistance against Rhizoctonia solani.

    PubMed

    Kern, Marcelo Fernando; Maraschin, Simone de Faria; Vom Endt, Débora; Schrank, Augusto; Vainstein, Marilene Henning; Pasquali, Giancarlo

    2010-04-01

    The chit1 gene from the entomopathogenic fungus Metarhizium anisopliae, encoding the endochitinase CHIT42, was placed under the control of the CaMV 35S promoter, and the resulting construct was transferred to tobacco. Seventeen kanamycin-resistant transgenic lines were recovered, and the presence of the transgene was confirmed by polymerase chain reactions and Southern blot hybridization. The number of chit1 copies was determined to be varying from one to four. Copy number had observable effects neither on plant growth nor development. Substantial heterogeneity concerning production of the recombinant chitinase, and both general and specific chitinolytic activities were detected in leaf extracts from primary transformants. The highest chitinase activities were found in plants harboring two copies of chit1 inserts at different loci. Progeny derived from self-pollination of the primary transgenics revealed a stable inheritance pattern, with transgene segregation following a mendelian dihybrid ratio. Two selected plants expressing high levels of CHIT42 were consistently resistant to the soilborne pathogen Rhizoctonia solani, suggesting a direct relationship between enzyme activity and reduction of foliar area affected by fungal lesions. To date, this is the first report of resistance to fungal attack in plants mediated by a recombinant chitinase from an entomopathogenic and acaricide fungus.

  19. RSIADB, a collective resource for genome and transcriptome analyses in Rhizoctonia solani AG1 IA.

    PubMed

    Chen, Lei; Ai, Peng; Zhang, Jinfeng; Deng, Qiming; Wang, Shiquan; Li, Shuangcheng; Zhu, Jun; Li, Ping; Zheng, Aiping

    2016-01-01

    Rice [Oryza sativa (L.)] feeds more than half of the world's population. Rhizoctonia solaniis a major fungal pathogen of rice causing extreme crop losses in all rice-growing regions of the world. R. solani AG1 IA is a major cause of sheath blight in rice. In this study, we constructed a comprehensive and user-friendly web-based database, RSIADB, to analyse its draft genome and transcriptome. The database was built using the genome sequence (10,489 genes) and annotation information for R. solani AG1 IA. A total of six RNAseq samples of R. solani AG1 IA were also analysed, corresponding to 10, 18, 24, 32, 48 and 72 h after infection of rice leaves. The RSIADB database enables users to search, browse, and download gene sequences for R. solani AG1 IA, and mine the data using BLAST, Sequence Extractor, Browse and Construction Diagram tools that were integrated into the database. RSIADB is an important genomic resource for scientists working with R. solani AG1 IA and will assist researchers in analysing the annotated genome and transcriptome of this pathogen. This resource will facilitate studies on gene function, pathogenesis factors and secreted proteins, as well as provide an avenue for comparative analyses of genes expressed during different stages of infection. Database URL:http://genedenovoweb.ticp.net:81/rsia/index.php.

  20. 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

  1. Unraveling Aspects of Bacillus amyloliquefaciens Mediated Enhanced Production of Rice under Biotic Stress of Rhizoctonia solani

    PubMed Central

    Srivastava, Suchi; Bist, Vidisha; Srivastava, Sonal; Singh, Poonam C.; Trivedi, Prabodh K.; Asif, Mehar H.; Chauhan, Puneet S.; Nautiyal, Chandra S.

    2016-01-01

    Rhizoctonia solani is a necrotrophic fungi causing sheath blight in rice leading to substantial loss in yield. Excessive and persistent use of preventive chemicals raises human health and environment safety concerns. As an alternative, use of biocontrol agents is highly recommended. In the present study, an abiotic stress tolerant, plant growth promoting rhizobacteria Bacillus amyloliquefaciens (SN13) is demonstrated to act as a biocontrol agent and enhance immune response against R. solani in rice by modulating various physiological, metabolic, and molecular functions. A sustained tolerance by SN13 primed plant over a longer period of time, post R. solani infection may be attributed to several unconventional aspects of the plants’ physiological status. The prolonged stress tolerance observed in presence of SN13 is characterized by (a) involvement of bacterial mycolytic enzymes, (b) sustained maintenance of elicitors to keep the immune system induced involving non-metabolizable sugars such as turanose besides the known elicitors, (c) a delicate balance of ROS and ROS scavengers through production of proline, mannitol, and arabitol and rare sugars like fructopyranose, β-D-glucopyranose and myoinositol and expression of ferric reductases and hypoxia induced proteins, (d) production of metabolites like quinazoline and expression of terpene synthase, and (e) hormonal cross talk. As the novel aspect of biological control this study highlights the role of rare sugars, maintenance of hypoxic conditions, and sucrose and starch metabolism in B. amyloliquefaciens (SN13) mediated sustained biotic stress tolerance in rice. PMID:27200058

  2. The population genetic structure of Rhizoctonia solani AG-3PT from potato in the Colombian Andes.

    PubMed

    Ferrucho, Rosa L; Ceresini, Paulo C; Ramirez-Escobar, Ursula M; McDonald, Bruce A; Cubeta, Marc A; García-Domínguez, Celsa

    2013-08-01

    The soilborne fungus Rhizoctonia solani anastomosis group 3 (AG-3PT) is a globally important potato pathogen. However, little is known about the population genetic processes affecting field populations of R. solani AG-3PT, especially in the South American Colombian Andes, which is near the center of diversity of the two most common groups of cultivated potato, Solanum tuberosum and S. phureja. We analyzed the genetic structure of 15 populations of R. solani AG-3PT infecting potato in Colombia using 11 simple-sequence repeat (SSR) markers. In total, 288 different multilocus genotypes were identified among 349 fungal isolates. Clonal fractions within field populations were 7 to 33%. RST statistics indicated a very low level of population differentiation overall, consistent with high contemporary gene flow, though moderate differentiation was found for the most distant southern populations. Genotype flow was also detected, with the most common genotype found widely distributed among field populations. All populations showed evidence of a mixed reproductive mode, including both asexual and sexual reproduction, but two populations displayed evidence of inbreeding.

  3. Isolation and characterization of siderophore producing antagonistic rhizobacteria against Rhizoctonia solani.

    PubMed

    Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K; Arora, Dilip K

    2014-06-01

    Plant protection through siderophore producing rhizobacteria (SPR) has emerged as a sustainable approach for crop health management. In present study, 220 bacteria isolated from tomato rhizosphere were screened for in vitro antagonistic activity against Rhizoctonia solani AG-4. Nine potent antagonistic strains viz., Alcaligenes sp. (MUN1, MB21, and MPF37), Enterobacter sp. (MPM1), Pseudomonas sp. (M10A and MB65), P. aeruginosa (MPF14 and MB123) and P. fluorescens (MPF47) were identified on the basis of physiological characters and 16S rDNA sequencing. These strains were able to produce hydrolytic enzymes, hydrogen cyanide, indole acetic acid, although, only few strains were able to solubilize phosphate. Two strains (MB123 and MPF47) showed significant disease reduction in glasshouse conditions were further evaluated under field conditions using three different application methods. Application of P. fluorescens (MPF47) in nursery as soil mix + seedling root treatments prior to transplantation resulted in significant disease reduction compared to control. Total chlorophyll and available iron were significantly higher in the MPF47 treated plants in contrast to infected control. In conclusion, siderophore producing bacteria MPF47 have strong biocontrol abilities and its application as soil mix + seedling root treatments provided strong shield to plant roots against R. solani and could be used for effective bio-management of pathogen.

  4. Molecular characterization and screening for sheath blight resistance using Malaysian isolates of Rhizoctonia solani.

    PubMed

    Nadarajah, Kalaivani; Omar, Nurfarahana Syuhada; 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.

  5. Antifungal activity of volatile compounds-producing Pseudomonas P2 strain against Rhizoctonia solani.

    PubMed

    Elkahoui, Salem; Djébali, Naceur; Yaich, Najeh; Azaiez, Sana; Hammami, Majdi; Essid, Rym; Limam, Ferid

    2015-01-01

    Several volatile organic compounds (VOCs) producing endophyte bacteria were isolated from the leaves of olive trees and tested for their antifungal activity against several pathogenic fungi. An antagonistic strain called P2 showed 97 % of homology with Pseudomonas sp. strains on the basis of its 16S rDNA sequence and biochemical properties. P2 strain drastically inhibited the growth of Rhizoctonia solani mycelia (86 %) at 5 day-post-confrontation (dpc) and strongly reduced fungi infection on potato slices at 10(7) bacteria ml(-1) for 3 and 7 dpc. P2 strain was also positive for protease activity as well as siderophore production. Light microscopy analysis showed that treatment of R. solani mycelia with P2 strain induced thickening of the cell-wall, vesiculation of protoplasm and blockage of fungal hyphae branching. VOCs analysis using GC-MS allowed the detection of two major products with m/z of 93.9910 and 125.9630 corresponding to dimethyl disulfide and dimethyl trisulfide respectively. VOCs-producing P2 strain could be a promising agent in the protection of tuber crops against fungal diseases.

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

    PubMed

    Rioux, Renee; Manmathan, Harish; Singh, Pratibha; de los Reyes, Benildo; Jia, Yulin; Tavantzis, Stellos

    2011-12-01

    Rhizoctonia solani, teleomorph Thanatephorus cucumeris, is a polyphagous necrotrophic plant pathogen of the Basidiomycete order that is split into 14 different anastomosis groups (AGs) based on hyphal interactions and host range. In this investigation, quantitative real-time PCR (qRT-PCR) techniques were used to determine potential pathogenicity factors of R. solani in the AG1-IA/rice and AG3/potato pathosystems. These factors were identified by mining for sequences of pathogen origin in a library of rice tissue infected with R. solani AG1-IA and comparing these sequences against the recently released R. solani AG3 genome. Ten genes common to both AGs and two specific to AG1-IA were selected for expression analysis by qRT-PCR. Results indicate that a number of genes are similarly expressed by AG1 and AG3 during the early stages of pathogenesis. Grouping of these pathogenicity factors based on relatedness of expression profiles suggests three key events are involved in R. solani pathogenesis: early host contact and infiltration, adjustment to the host environment, and pathogen proliferation through necrotic tissue. Further studies of the pathogenesis-associated genes identified in this project will enable more precise elucidation of the molecular mechanisms that allow for the widespread success of R. solani as a phytopathogen and allow for more targeted, effective methods of management.

  7. [Identification of chemicals in root exudates of potato and their effects on Rhizoctonia solani].

    PubMed

    Zhang, Wen-ming; Qiu, Hui-zhen; Zhang, Chun-hong; Hai, Long

    2015-03-01

    This study was conducted to identify chemicals in root exudates and their effect on Rhizoctonia solani in potato cropping systems. Root exudates were collected from the fields with 5 years of continuous potato cropping in comparison with rotational cropping of potato and other crops, using in-house made root boxes at the seedling and squaring stages. Chemicals in the root exudates were identified using the GC-MS method. The results showed that glucide concentration was the highest in the root exudates, followed by organic acids. Compared with the rotational cropping, the continuous cropping significantly decreased the glucide content and increased the content of organic acids in the root exudates. The contents of almitic acid in root exudates under continuous cropping was 0.94% at seedling stage and 1.4% at squaring stage, the dibutyl phthalate was 0.15%, whereas under rotational cropping, those values were decreased to 0.15%, 0.2%, and being negligible, respectively. The root exudates promoted the growth of R. solani, especially under continuous potato cropping. The simulation test showed that the palmitic acid and dibutyl phthalate in root exudates could promote the growth of R. solani.

  8. Factors affecting antifungal activity of Streptomyces philanthi RM-1-138 against Rhizoctonia solani.

    PubMed

    Boukaew, Sawai; Prasertsan, Poonsuk

    2014-01-01

    Sheath blight disease of rice caused by Rhizoctonia solani Kühn is economically important disease in most of the world's rice growing areas. The disease causes severe yield losses of >20% of rice in Thailand. Our previous investigation reported the antifungal activity of Streptomyces philanthi RM-1-138 against R. solani PTRRC-9. In this study, glucose yeast-malt extract medium, initial pH of 7.5 and a temperature of 30 °C were found to be optimum for both cell growth and antifungal activity of S. philanthi RM-1-138. The inhibition of 94 and 100% on the growth of R. solani PTRRC-9 were achieved from the antifungal metabolites of the 6 and 9-days-old culture filtrates of S. philanthi RM-1-138, respectively. Heat treatment on the culture filtrate had slight effect on its antifungal activity. The culture broth demonstrated higher antifungal activity on growth of R. solani PTRRC-9 (90.4%) than the culture filtrate (31.5%) and its effective dose was at 0.1% (v/v). The present results indicated the possibilities of using either the culture broth or culture filtrate of S. philanthi RM-1-138 to inhibit growth of R. solani PTRRC-9.

  9. Triallelic SNP-mediated genotyping of regenerated protoplasts of the heterokaryotic fungus Rhizoctonia solani.

    PubMed

    Thomas, Elizabeth; Pakala, Suman; Fedorova, Natalie D; Nierman, William C; Cubeta, Marc A

    2012-04-15

    The aneuploid and heterokaryotic nuclear condition of the soil fungus Rhizoctonia solani have provided challenges in obtaining a complete genome sequence. To better aid in the assembly and annotation process, a protoplast and single nucleotide polymorphism (SNP)-based method was developed to identify regenerated protoplasts with a reduced nuclear genome. Protocol optimization experiments showed that enzymatic digestion of mycelium from a 24 h culture of R. solani increased the proportion of protoplasts with a diameter of ≤7.5 μm and 1-4 nuclei. To determine whether strains regenerated from protoplasts with a reduced number of nuclei were genetically different from the parental strain, triallelic SNPs identified from variance records of the genomic DNA sequence reads of R. solani were used in PCR-based genotyping assays. Results from 16 of the 24 SNP-based PCR assays provided evidence that one of the three alleles was missing in the 11 regenerated protoplast strains, suggesting that these strains represent a reduced genomic complement of the parental strain. The protoplast and triallelic SNP-based method used in this study may be useful in strain development and analysis of other basidiomycete fungi with complex nuclear genomes.

  10. 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.

  11. 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

  12. Do fungicides used to control Rhizoctonia solani impact the non-target arbuscular mycorrhizal fungus Rhizophagus irregularis?

    PubMed

    Buysens, Catherine; Dupré de Boulois, Hervé; Declerck, Stéphane

    2015-05-01

    There is growing evidence that the application of biocontrol organisms (e.g., Pseudomonas and Bacillus spp., arbuscular mycorrhizal fungi-AMF) is a feasible option to reduce incidence of plant pathogens in an integrated control strategy. However, the utilization of these microorganisms, in particular AMF, may be threatened by the application of fungicides, a widely-used measure to control Rhizoctonia solani in various crops among which potato. Prior to their application, it is thus important to determine the impact of fungicides on AMF. The present study investigated, under in vitro controlled conditions, the impact of azoxystrobin (a systemic broad-spectrum fungicide), flutolanil (a systemic Basidiomycota-specific fungicide), and pencycuron (a contact Rhizoctonia-specific fungicide) and their respective formulations (Amistar, Monarch, and Monceren) on the growth and development of the AMF Rhizophagus irregularis MUCL 41833 (spore germination, root colonization, extraradical mycelium development, and spore production) at doses used to control R. solani. Results demonstrated that azoxystrobin and its formulation Amistar, at threshold values for R. solani control (estimated by the half maximal inhibitory concentration, IC50, on a dry weight basis), did not affect spore germination and potato root colonization by R. irregularis, while the development of extra-radical mycelium and spore production was reduced at 10 times the threshold value. Flutolanil and its formulation Monarch at threshold value did not affect spore germination or extra-radical development but decreased root colonization and arbuscule formation. At threshold value, pencycuron and its formulation Monceren, did not affect spore germination and intra- or extraradical development of R. irregularis. These results suggest that azoxystrobin and pencycuron do not affect the AMF at threshold concentrations to control R. solani in vitro, while flutolanil (as formulation) impacts the intraradical phase of the

  13. Diversity of Rhizoctonia solani associated with pulse crops in different agro-ecological regions of India.

    PubMed

    Dubey, Sunil C; Tripathi, Aradhika; Upadhyay, Balendu K; Deka, Utpal K

    2014-06-01

    Four hundred seventy Rhizoctonia solani isolates from different leguminous hosts originating from 16 agro-ecological regions of India covering 21 states and 72 districts were collected. The disease incidence caused by R. solani varied from 6.8 to 22.2 % in the areas surveyed. Deccan plateau and central highlands, hot sub-humid ecoregion followed by northern plain and central highlands and hot semi-arid ecoregion showed the highest disease incidence. R. solani isolates were highly variable in growth diameter, number, size and pattern of sclerotia formation as well as hyphal width. The isolates obtained from aerial part of the infected plants showing web blight symptoms produced sclerotia of 1-2 mm in size whereas, the isolates obtained from infected root of the plants showing wet root rot symptoms produced microsclerotia (<1 mm). Majority of R. solani isolates showed <8 μm hyphal diameter. Based on morphological characters the isolates were categorized into 49 groups. Seven anastomosis groups (AGs) were identified among the populations of R. solani associated with the pulse crops. The frequency (25.6 %) of AG3 was the highest followed by AG2-3 (20.9 %) and AG5 (17.4 %). The cropping sequence of rice/sorghum/wheat-chickpea/mungbean/urdbean/cowpea/ricebean influenced the dominance of AG1 (16.3 %). Phylogenetic analysis utilizing ITS-5.8S rDNA gene sequences indicated high level of genetic similarity among isolates representing different AGs, crops and regions. ITS groups did not correspond to the morphological characters. The sequence data from this article has been deposited with NCBI data libraries with JF701707 to JF701795 accession numbers.

  14. Recombinant expression and characterization of a L-amino acid oxidase from the fungus Rhizoctonia solani.

    PubMed

    Hahn, Katharina; Neumeister, Katrin; Mix, Andreas; Kottke, Tilman; Gröger, Harald; Fischer von Mollard, Gabriele

    2017-04-01

    L-Amino acid oxidases (L-AAOs) catalyze the oxidative deamination of L-amino acids to the corresponding α-keto acids, ammonia, and hydrogen peroxide. L-AAOs are homodimeric enzymes with FAD as a non-covalently bound cofactor. They are of potential interest for biotechnological applications. However, heterologous expression has not succeeded in producing large quantities of active recombinant L-AAOs with a broad substrate spectrum so far. Here, we report the heterologous expression of an active L-AAO from the fungus Rhizoctonia solani in Escherichia coli as a fusion protein with maltose-binding protein (MBP) as a solubility tag. After purification, it was possible to remove the MBP-tag proteolytically without influencing the enzyme activity. MBP-rsLAAO1 and 9His-rsLAAO1 converted basic and large hydrophobic L-amino acids as well as methyl esters of these L-amino acids. The progress of the conversion of L-phenylalanine and L-leucine into the corresponding α-keto acids was determined by HPLC and (1)H-NMR analysis of reaction mixtures, respectively. Enzymatic activity was stimulated 50-100-fold by SDS treatment. K m values ranging from 0.9-10 mM and v max values from 3 to 10 U mg(-1) were determined after SDS activation of 9His-rsLAAO1 for the best substrates. The enzyme displayed a broad pH optimum between pH 7.0 and 9.5. In summary, a successful overexpression of recombinant L-AAO in E. coli was established that results in a promising enzymatic activity and a broad substrate spectrum for biotechnological application.

  15. Genetic diversity of Rhizoctonia solani associated with potato tubers in France.

    PubMed

    Fiers, Marie; Edel-Hermann, Véronique; Héraud, Cécile; Gautheron, Nadine; Chatot, Catherine; Le Hingrat, Yves; Bouchek-Mechiche, Karima; Steinberg, Christian

    2011-01-01

    The soilborne fungus Rhizoctonia solani is a pathogen of many plants and causes severe damage in crops around the world. Strains of R. solani from the anastomosis group (AG) 3 attack potatoes, leading to great yield losses and to the downgrading of production. The study of the genetic diversity of the strains of R. solani in France allows the structure of the populations to be determined and adapted control strategies against this pathogen to be established. The diversity of 73 French strains isolated from tubers grown in the main potato seed production areas and 31 strains isolated in nine other countries was assessed by phylogenetic analyses of (i) the internal transcribed spacer sequences (ITS1 and ITS2) of ribosomal RNA (rRNA), (ii) a part of the gene tef-1α and (iii) the total DNA fingerprints of each strain established by amplified fragment length polymorphism (AFLP). The determination of the AGs of R. solani based on the sequencing of the ITS region showed three different AGs among our collection (60 AG 3 PT, 8 AG 2-1 and 5 AG 5). Grouping of the strains belonging to the same AG was confirmed by sequencing of the gene tef-1α used for the first time to study the genetic diversity of R. solani. About 42% of ITS sequences and 72% of tef-1α sequences contained polymorphic sites, suggesting that the cells of R. solani strains contain several copies of ITS and the tef-1α gene within the same nucleus or between different nuclei. Phylogenetic trees showed a greater genetic diversity within AGs in tef-1α sequences than in ITS sequences. The AFLP analyses showed an even greater diversity among the strains demonstrating that the French strains of R. solani isolated from potatoes were not a clonal population. Moreover there was no relationship between the geographical origins of the strains or the variety from which they were isolated and their genetic diversity.

  16. Mechanism of the generation of new somatic compatibility groups within Thanatephorus cucumeris (Rhizoctonia solani).

    PubMed

    Qu, Ping; Saldajeno, Mary Grace B; Hyakumachi, Mitsuro

    2013-01-01

    Single-basidiospore isolates (SBIs) were obtained from field isolates of Thanatephorus cucumeris (Rhizoctonia solani) AG-1 IC and AG-2-2 IV. Formation of distinctive tufts, a recognized feature of heterokaryon synthesis, was observed, and isolates derived from hyphal-tipped tuft hyphae were obtained following pairings between various strains. Three distinctive types of tufts were formed: the fibrous type of mating-compatible homokaryon-homokaryon (Hom-Hom) pairings, the sparse type between heterokaryon-homokaryon (Het-Hom) pairings originating from one parent, and the compact type between Het-Hom pairings originating from different parents. Amplified Fragment Length Polymorphism (AFLP) profile of fingerprints of these tuft isolates verified that they were all heterokaryotic. Because of heterokaryotic vigor, the growth and pathogenicity of the majority of tuft isolates increased compared with their contributing SBIs. New somatic compatibility groups (SCGs) that were different from parental field isolates occurred following heterokaryon formation within T. cucumeris. Tuft isolates produced by Hom-Hom and Het-Hom pairings among isolates of different parents yielded no somatic compatibility with the original parent isolates and a high frequency of new SCGs (62-100%). This was in contrast to those produced by Hom-Hom and Het-Hom pairings among isolates with a common parent that yielded only 12-37% new SCGs. The SCG diversity of R. solani in the field may be attributed to new fitter heterokaryons formed between a heterokaryon of one pair of parents and a homokaryon of another parent pair. This mechanism greatly contributes to genetic diversity in the field and accounts for the failure to recover the expected distribution of SCGs from a field population.

  17. 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

  18. Effectiveness of 3 antagonistic bacterial isolates to control Rhizoctonia solani Kühn on lettuce and potato.

    PubMed

    Grosch, Rita; Faltin, Franziska; Lottmann, Jana; Kofoet, A; Berg, Gabriele

    2005-04-01

    Rhizoctonia solani causes yield losses in numerous economically important European crops. To develop a biocontrol strategy, 3 potato-associated ecto- and endophytically living bacterial strains Pseudomonas fluorescens B1, Pseudomonas fluorescens B2, and Serratia plymuthica B4 were evaluated against R. solani in potato and in lettuce. The disease-suppression effect of the 3 biocontrol agents (BCAs) was tested in a growth chamber and in the field. In growth chamber experiments, all 3 BCAs completely or significantly limited the dry mass (DM) losses on lettuce and the disease severity (DS) caused by R. solani on potato sprouts. Strain B1 showed the highest suppression effect (52% on average) on potato. Under field conditions, the DS on both crops, which were bacterized, decreased significantly, and the biomass losses on lettuce decreased significantly as well. The greatest disease-suppression effect on potato was achieved by strain B1 (37%), followed by B2 (33%) and then B4 (31%), whereas the marketable tuber yield increased up to 12% (B1), 6% (B2), and 17% (B4) compared with the pathogen control at higher disease pressure. Furthermore, in all experiments, B1 proved to be the most effective BCA against R. solani. Therefore, this BCA could be a candidate for developing a commercial product against Rhizoctonia diseases. To our knowledge, this is the first report on the high potential of endophytes to be used as a biological control agent against R. solani under field conditions.

  19. Blackpatch of Clover, Cause of Slobbers Syndrome: A Review of the Disease and the Pathogen, Rhizoctonia leguminicola

    PubMed Central

    Kagan, Isabelle A.

    2016-01-01

    Rhizoctonia leguminicola Gough and Elliott is a widely used name for the causal agent of blackpatch disease of red clover (Trifolium pratense L.). This fungal pathogen produces alkaloids (slaframine and swainsonine) that affect grazing mammals. Slaframine causes livestock to salivate profusely, and swainsonine causes neurological problems. Although the blackpatch fungus was classified as a Rhizoctonia species (phylum Basidiomycota), morphological studies have indicated that it is in the phylum Ascomycota, and sequencing data have indicated that it may be a new genus of ascomycete. The effects of the alkaloids on grazing mammals and their biosynthetic pathways have been extensively studied. In contrast, few studies have been done on management of the disease, which requires a greater understanding of the pathogen. Methods of disease management have included seed treatments and fungicides, but these have not been investigated since the 1950s. Searches for resistant cultivars have been limited. This review summarizes the biological effects and biosynthetic precursors of slaframine and swainsonine. Emphasis is placed on current knowledge about the epidemiology of blackpatch disease and the ecology and taxonomy of the pathogen. Possibilities for future research and disease management efforts are suggested. PMID:26858953

  20. Effect of bacterial antagonists on lettuce: active biocontrol of Rhizoctonia solani and negligible, short-term effects on nontarget microorganisms.

    PubMed

    Scherwinski, Katja; Grosch, Rita; Berg, Gabriele

    2008-04-01

    The aim of this study was to assess the biocontrol efficacy against Rhizoctonia solani of three bacterial antagonists introduced into naturally Rhizoctonia-infested lettuce fields and to analyse their impact on the indigenous plant-associated bacteria and fungi. Lettuce seedlings were inoculated with bacterial suspensions of two endophytic strains, Serratia plymuthica 3Re4-18 and Pseudomonas trivialis 3Re2-7, and with the rhizobacterium Pseudomonas fluorescens L13-6-12 7 days before and 5 days after planting in the field. Similar statistically significant biocontrol effects were observed for all applied bacterial antagonists compared with the uninoculated control. Single-strand conformation polymorphism analysis of 16S rRNA gene or ITS1 fragments revealed a highly diverse rhizosphere and a less diverse endophytic microbial community for lettuce. Representatives of several bacterial (Alpha-, Beta- and Gammaproteobacteria, Firmicutes, Bacteriodetes), fungal (Ascomycetes, Basidiomycetes) and protist (Oomycetes) groups were present inside or on lettuce plants. Surprisingly, given that lettuce is a vegetable that is eaten raw, species of genera such as Flavobacterium, Burkholderia, Staphylococcus, Cladosporium and Aspergillus, which contain potentially human pathogenic strains, were identified. Analysis of the indigenous bacterial and endophytic fungal populations revealed only negligible, short-term effects resulting from the bacterial treatments, and that they were more influenced by field site, plant growth stage and microenvironment.

  1. 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. ...

  2. 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...

  3. Yield responses of three onion cultivars to stunting caused by Rhizoctonia spp. in the Columbia Basin of Oregon and Washington, 2012.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia spp. cause patches of stunted onion plants in onion bulbs crop in the Columbia Basin of Washington and Oregon when onion crops are planted in sandy soils of this semi-arid region following winter cereal cover crops. A herbicide application is used to kill the cereal cover crop, usually ...

  4. 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....

  5. Mid-infared and near-infared detection of Rhizoctonia solani AG 2-2IIIB on barley based artifical inoculum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The amount of Rhizoctonia solani in the soil and how much is needed to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities natually found in soil, and the low sensitivity of traditional serial dilution assays. We invest...

  6. Mid-infared (MidIR) and near-infared (NIR) dection of rhizoctonia solani AG 2-2 IIIB on barley based artificial inoculum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The amount of Rhizoctonia solani in the soil and how much is needed to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities natually found in soil, and the low sensitivity of traditional serial dilution assays. We invest...

  7. Proteomic investigation of Rhizoctonia solani AG 4 identifies secretome and mycelial proteins with roles in plant cell wall degradation and virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia solani AG 4 is a soilborne necrotrophic fungal plant pathogen that causes economically important diseases on agronomic crops worldwide. Our long-term goal is to elucidate the molecular basis of pathogenesis of isolates of R. solani AG 4 in an effort to develop more effective control meth...

  8. Carbon source-dependent effects of anaerobic soil disinfestation on soil microbiome and suppression of rhizoctonia solani AG-5 and pratylenchus penetrans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of carbon source on efficacy of anaerobic soil disinfestation (ASD) toward suppression of apple root infection by Rhizoctonia solani AG-5 and Pratylenchus penetrans was examined. Orchard grass (GR), rice bran (RB), ethanol (ET), composted steer manure (CM) and Brassica juncea seed meal (S...

  9. Deep Sequencing Analysis Reveals the Mycoviral Diversity of the Virome of an Avirulent Isolate of Rhizoctonia solani AG-2-2 IV

    PubMed Central

    Bartholomäus, Anika; Wibberg, Daniel; Winkler, Anika; Pühler, Alfred; Schlüter, Andreas; Varrelmann, Mark

    2016-01-01

    Rhizoctonia solani represents an important plant pathogenic Basidiomycota species complex and the host of many different mycoviruses, as indicated by frequent detection of dsRNA elements in natural populations of the fungus. To date, eight different mycoviruses have been characterized in Rhizoctonia and some of them have been reported to modulate its virulence. DsRNA extracts of the avirulent R. solani isolate DC17 (AG2-2-IV) displayed a diverse pattern, indicating multiple infections with mycoviruses. Deep sequencing analysis of the dsRNA extract, converted to cDNA, revealed that this isolate harbors at least 17 different mycovirus species. Based on the alignment of the conserved RNA-dependent RNA-polymerase (RdRp) domain, this viral community included putative members of the families Narnaviridae, Endornaviridae, Partitiviridae and Megabirnaviridae as well as of the order Tymovirales. Furthermore, viruses, which could not be assigned to any existing family or order, but showed similarities to so far unassigned species like Sclerotinia sclerotiorum RNA virus L, Rhizoctonia solani dsRNA virus 1, Aspergillus foetidus slow virus 2 or Rhizoctonia fumigata virus 1, were identified. This is the first report of a fungal isolate infected by 17 different viral species and a valuable study case to explore the diversity of mycoviruses infecting R. solani. PMID:27814394

  10. Sanitation Can Be A Foundation Disease Management Tool: Potential Of Spreading Binucleate Rhizoctonia from Nursery Propagation Floors To Trays Containing Azalea 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 being con...

  11. 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

  12. Integrated options for the management of black root rot of strawberry caused by Rhizoctonia solani Kuhn.

    PubMed

    Asad-Uz-Zaman, Md; Bhuiyan, Mohammad Rejwan; Khan, Mohammad Ashik Iqbal; Alam Bhuiyan, Md Khurshed; Latif, Mohammad Abdul

    2015-02-01

    An investigation was made to manage strawberry black root rot caused by Rhizoctonia solani (R. solani) through the integration of Trichoderma harzianum (T. harzianum) isolate STA7, mustard oil cake and Provax 200. A series of preliminary experiments were conducted to select a virulent isolate of R. solani, an effective isolate of T. harzianum, a suitable organic amendment, and a suitable fungicide before setting the experiment for integration. The pathogenicity of the selected four isolates of R. solani was evaluated against strawberry and isolate SR1 was selected as the test pathogen due to its highest virulent (95.47% mortality) characteristics. Among the 20 isolates of T. harzianum, isolate STA7 showed maximum inhibition (71.97%) against the test pathogen (R. solani). Among the fungicides, Provax-200 was found to be more effective at lowest concentration (100 ppm) and highly compatible with Trichoderma isolates STA7. In the case of organic amendments, maximum inhibition (59.66%) of R. solani was obtained through mustard oil cake at the highest concentration (3%), which was significantly superior to other amendments. Minimum percentages of diseased roots were obtained with pathogen (R. solani)+Trichoderma+mustard oil cake+Provax-200 treatment, while the highest was observed with healthy seedlings with a pathogen-inoculated soil. In the case of leaf and fruit rot diseases, significantly lowest infected leaves as well as fruit rot were observed with a pathogen+Trichoderma+mustard oil cake+Provax-200 treatment in comparison with the control. A similar trend of high effectiveness was observed by the integration of Trichoderma, fungicide and organic amendments in controlling root rot and fruit diseases of strawberry. Single application of Trichoderma isolate STA7, Provax 200 or mustard oil cake did not show satisfactory performance in terms of disease-free plants, but when they were applied in combination, the number of healthy plants increased significantly. The

  13. 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

  14. Comparative proteomic analysis reveals intracellular targets for bacillomycin L to induce Rhizoctonia solani Kühn hyphal cell death.

    PubMed

    Zhang, Bao; Qin, Yuxuan; Han, Yuzhu; Dong, Chunjuan; Li, Pinglan; Shang, Qingmao

    2016-09-01

    Bacillomycin L, a natural iturinic lipopeptide produced by Bacillus amyloliquefaciens, is characterized by strong antifungal activity against a variety of agronomically important filamentous fungi including Rhizoctonia solani Kühn. To further understand its antifungal actions, proteomes were comparatively studied within R. solani hyphal cells treated with or without bacillomycin L. The results show that 39 proteins were alternatively expressed within cells in response to this lipopeptide, which are involved in stress response, carbohydrate, amino acid and nucleotide metabolism, cellular component organization, calcium homeostasis, protein degradation, RNA processing, gene transcription, and others, suggesting that, in addition to inducing cell membrane permeabilization, iturin exhibits antibiotic activities by targeting intracellular molecules. Based on these results, a model of action of bacillomycin L against R. solani hyphal cells was proposed. Our study provides new insight into the antibiotic mechanisms of iturins.

  15. The double life of Ceratobasidium: orchid mycorrhizal fungi and their potential for biocontrol of Rhizoctonia solani sheath blight of rice.

    PubMed

    Mosquera-Espinosa, Ana Teresa; Bayman, Paul; Prado, Gustavo A; Gómez-Carabalí, Arnulfo; Otero, J Tupac

    2013-01-01

    Ceratobasidium includes orchid mycorrhizal symbionts, plant pathogens and biocontrol agents of soilborne plant pathogens. It is not known to what extent members of the first guild also can participate in the others. Ceratobasidium spp. were isolated from roots of Colombian orchids and identified by phylogeny based on nrITS sequences. Phylogenetic grouping of Ceratobasidium spp. isolates corresponded to orchid host substrate (epiphytic vs. terrestrial). Isolates were tested for virulence on rice and for biocontrol of Rhizoctonia solani, causal agent of sheath blight of rice. All Ceratobasidium spp. isolates caused some signs of sheath blight but significantly less than a pathogenic R. solani used as a positive control. When Ceratobasidium spp. isolates were inoculated on rice seedlings 3 d before R. solani, they significantly reduced disease expression compared to controls inoculated with R. solani alone. The use of Ceratobasidium spp. from orchids for biological control is novel, and biodiverse countries such as Colombia are promising places to look for new biocontrol agents.

  16. Metabolomic study of two rice lines infected by Rhizoctonia solani in negative ion mode by CE/TOF-MS.

    PubMed

    Suharti, Woro Sri; Nose, Akihiro; Zheng, Shao-Hui

    2016-11-01

    Rhizoctonia solani is a fungal pathogen that causes sheath blight disease in rice plants. In this study, metabolomic analysis using CE/TOF-MS in negative ion mode was used to investigate the resistance response of resistant and susceptible rice lines (32R and 29S, respectively) due to R. solani infection. Two rice lines showed different responses to the infection of R. solani. In 32R, R. solani infection induced significant increases in adenosine diphosphate (ADP), glyceric acid, mucic acid and jasmonic acid. In 29S, inosine monophosphate (IMP) was involved in the plant response to R. solani infection. Phenol compounds showed an increase as a response of the rice lines to R. solani infection. The study suggests that R. solani infection effects in 32R are associated with the induction of plant metabolic processes such as respiration, photorespiration, pectin synthesis, and lignin accumulation. In 29S, the R. solani infection is suggested to correlate with nitrogen metabolism.

  17. Draft genome sequence of the sugar beet pathogen Rhizoctonia solani AG2-2IIIB strain BBA69670.

    PubMed

    Wibberg, Daniel; Andersson, Louise; Rupp, Oliver; Goesmann, Alexander; Pühler, Alfred; Varrelmann, Mark; Dixelius, Christina; Schlüter, Andreas

    2016-03-20

    Rhizoctonia solani is a widespread plant pathogenic fungus featuring a broad host range including several economically important crops. Accordingly, genome analyses of R. solani isolates are important to uncover their pathogenic potential. Draft genome sequences for four R. solani isolates representing three of the 14 R. solani anastomosis groups (AGs) are available. Here, we present the first draft genome sequence for an R. solani AG2-2IIIB isolate that is pathogenic on sugar beet. The fungal genome was assembled in 2065 scaffolds consisting of 5826 contigs amounting to a size of about 52 Mb which is larger than any other R. solani isolate known today. Genes potentially encoding cellulolytic, lignolytic and pectinolytic enzymes were identified.

  18. 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.

  19. Mobile elements and mitochondrial genome expansion in the soil fungus and potato pathogen Rhizoctonia solani AG-3.

    PubMed

    Losada, Liliana; Pakala, Suman B; Fedorova, Natalie D; Joardar, Vinita; Shabalina, Svetlana A; Hostetler, Jessica; Pakala, Suchitra M; Zafar, Nikhat; Thomas, Elizabeth; Rodriguez-Carres, Marianela; Dean, Ralph; Vilgalys, Rytas; Nierman, William C; Cubeta, Marc A

    2014-03-01

    The soil fungus Rhizoctonia solani is an economically important pathogen of agricultural and forestry crops. Here, we present the complete sequence and analysis of the mitochondrial genome of R. solani, field isolate Rhs1AP. The genome (235 849 bp) is the largest mitochondrial genome of a filamentous fungus sequenced to date and exhibits a rich accumulation of introns, novel repeat sequences, homing endonuclease genes, and hypothetical genes. Stable secondary structures exhibited by repeat sequences suggest that they comprise functional, possibly catalytic RNA elements. RNA-Seq expression profiling confirmed that the majority of homing endonuclease genes and hypothetical genes are transcriptionally active. Comparative analysis suggests that the mitochondrial genome of R. solani is an example of a dynamic history of expansion in filamentous fungi.

  20. A gene for plant protection: expression of a bean polygalacturonase inhibitor in tobacco confers a strong resistance against Rhizoctonia solani and two oomycetes.

    PubMed

    Borras-Hidalgo, Orlando; Caprari, Claudio; Hernandez-Estevez, Ingrid; Lorenzo, Giulia De; Cervone, Felice

    2012-01-01

    We have tested whether a gene encoding a polygalacturonase-inhibiting protein (PGIP) protects tobacco against a fungal pathogen (Rhizoctonia solani) and two oomycetes (Phytophthora parasitica var. nicotianae and Peronospora hyoscyami f. sp. tabacina). The trials were performed in greenhouse conditions for R. solani and P. parasitica and in the field for P. hyoscyami. Our results show that expression of PGIP is a powerful way of engineering a broad-spectrum disease resistance.

  1. The importance of associations with saprotrophic non-Rhizoctonia fungi among fully mycoheterotrophic orchids is currently under-estimated: novel evidence from sub-tropical Asia

    PubMed Central

    Lee, Yung-I; Yang, Chih-Kai; Gebauer, Gerhard

    2015-01-01

    Background and Aims Most fully mycoheterotrophic (MH) orchids investigated to date are mycorrhizal with fungi that simultaneously form ectomycorrhizas with forest trees. Only a few MH orchids are currently known to be mycorrhizal with saprotrophic, mostly wood-decomposing, fungi instead of ectomycorrhizal fungi. This study provides evidence that the importance of associations between MH orchids and saprotrophic non-Rhizoctonia fungi is currently under-estimated. Methods Using microscopic techniques and molecular approaches, mycorrhizal fungi were localized and identified for seven MH orchid species from four genera and two subfamilies, Vanilloideae and Epidendroideae, growing in four humid and warm sub-tropical forests in Taiwan. Carbon and nitrogen stable isotope natural abundances of MH orchids and autotrophic reference plants were used in order to elucidate the nutritional resources utilized by the orchids. Key Results Six out of the seven MH orchid species were mycorrhizal with either wood- or litter-decaying saprotrophic fungi. Only one orchid species was associated with ectomycorrhizal fungi. Stable isotope abundance patterns showed significant distinctions between orchids mycorrhizal with the three groups of fungal hosts. Conclusions Mycoheterotrophic orchids utilizing saprotrophic non-Rhizoctonia fungi as a carbon and nutrient source are clearly more frequent than hitherto assumed. On the basis of this kind of nutrition, orchids can thrive in deeply shaded, light-limiting forest understoreys even without support from ectomycorrhizal fungi. Sub-tropical East Asia appears to be a hotspot for orchids mycorrhizal with saprotrophic non-Rhizoctonia fungi. PMID:26113634

  2. 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.

  3. 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.

  4. Proteomic Analysis of Rhizoctonia solani Identifies Infection-specific, Redox Associated Proteins and Insight into Adaptation to Different Plant Hosts*

    PubMed Central

    Anderson, Jonathan P.; Hane, James K.; Stoll, Thomas; Pain, Nicholas; Hastie, Marcus L.; Kaur, Parwinder; Hoogland, Christine; Gorman, Jeffrey J.; Singh, Karam B.

    2016-01-01

    Rhizoctonia solani is an important root infecting pathogen of a range of food staples worldwide including wheat, rice, maize, soybean, potato and others. Conventional resistance breeding strategies are hindered by the absence of tractable genetic resistance in any crop host. Understanding the biology and pathogenicity mechanisms of this fungus is important for addressing these disease issues, however, little is known about how R. solani causes disease. This study capitalizes on recent genomic studies by applying mass spectrometry based proteomics to identify soluble, membrane-bound and culture filtrate proteins produced under wheat infection and vegetative growth conditions. Many of the proteins found in the culture filtrate had predicted functions relating to modification of the plant cell wall, a major activity required for pathogenesis on the plant host, including a number found only under infection conditions. Other infection related proteins included a high proportion of proteins with redox associated functions and many novel proteins without functional classification. The majority of infection only proteins tested were confirmed to show transcript up-regulation during infection including a thaumatin which increased susceptibility to R. solani when expressed in Nicotiana benthamiana. In addition, analysis of expression during infection of different plant hosts highlighted how the infection strategy of this broad host range pathogen can be adapted to the particular host being encountered. Data are available via ProteomeXchange with identifier PXD002806. PMID:26811357

  5. FT-ICR/MS and GC-EI/MS Metabolomics Networking Unravels Global Potato Sprout's Responses to Rhizoctonia solani Infection

    PubMed Central

    Aliferis, Konstantinos A.; Jabaji, Suha

    2012-01-01

    The complexity of plant-pathogen interactions makes their dissection a challenging task for metabolomics studies. Here we are reporting on an integrated metabolomics networking approach combining gas chromatography/mass spectrometry (GC/MS) with Fourier transform ion cyclotron resonance/mass spectrometry (FT-ICR/MS) and bioinformatics analyses for the study of interactions in the potato sprout-Rhizoctonia solani pathosystem and the fluctuations in the global metabolome of sprouts. The developed bioanalytical and bioinformatics protocols provided a snapshot of the sprout's global metabolic network and its perturbations as a result of pathogen invasion. Mevalonic acid and deoxy-xylulose pathways were substantially up-regulated leading to the biosynthesis of sesquiterpene alkaloids such as the phytoalexins phytuberin, rishitin, and solavetivone, and steroidal alkaloids having solasodine and solanidine as their common aglycons. Additionally, the perturbation of the sprout's metabolism was depicted in fluctuations of the content of their amino acids pool and that of carboxylic and fatty acids. Components of the systemic acquired resistance (SAR) and hypersensitive reaction (HR) such as azelaic and oxalic acids were detected in increased levels in infected sprouts and strategies of the pathogen to overcome plant defense were proposed. Our metabolic approach has not only greatly expanded the multitude of metabolites previously reported in potato in response to pathogen invasion, but also enabled the identification of bioactive plant-derived metabolites providing valuable information that could be exploited in biotechnology, biomarker-assisted plant breeding, and crop protection for the development of new crop protection agents. PMID:22880040

  6. Overexpression of snakin-1 gene enhances resistance to Rhizoctonia solani and Erwinia carotovora in transgenic potato plants.

    PubMed

    Almasia, Natalia I; Bazzini, Ariel A; Hopp, H Esteban; Vazquez-Rovere, Cecilia

    2008-05-01

    Snakin-1 (SN1), a cysteine-rich peptide with broad-spectrum antimicrobial activity in vitro, was evaluated for its ability to confer resistance to pathogens in transgenic potatoes. Genetic variants of this gene were cloned from wild and cultivated Solanum species. Nucleotide sequences revealed highly evolutionary conservation with 91-98% identity values. Potato plants (S. tuberosum subsp. tuberosum cv. Kennebec) were transformed via Agrobacterium tumefaciens with a construct encoding the S. chacoense SN1 gene under the regulation of the ubiquitous CaMV 35S promoter. Transgenic lines were molecularly characterized and challenged with either Rhizoctonia solani or Erwinia carotovora to analyse whether constitutive in vivo overexpression of the SN1 gene may lead to disease resistance. Only transgenic lines that accumulated high levels of SN1 mRNA exhibited significant symptom reductions of R. solani infection such as stem cankers and damping-off. Furthermore, these overexpressing lines showed significantly higher survival rates throughout the fungal resistance bioassays. In addition, the same lines showed significant protection against E. carotovora measured as: a reduction of lesion areas (from 46.5 to 88.1% with respect to the wild-type), number of fallen leaves and thickened or necrotic stems. Enhanced resistance to these two important potato pathogens suggests in vivo antifungal and antibacterial activity of SN1 and thus its possible biotechnological application.

  7. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat

    PubMed Central

    Foley, Rhonda C.; Kidd, Brendan N.; Hane, James K.; Anderson, Jonathan P.; Singh, Karam B.

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction. PMID:27031952

  8. Proteomic Analysis of Rhizoctonia solani Identifies Infection-specific, Redox Associated Proteins and Insight into Adaptation to Different Plant Hosts.

    PubMed

    Anderson, Jonathan P; Hane, James K; Stoll, Thomas; Pain, Nicholas; Hastie, Marcus L; Kaur, Parwinder; Hoogland, Christine; Gorman, Jeffrey J; Singh, Karam B

    2016-04-01

    Rhizoctonia solaniis an important root infecting pathogen of a range of food staples worldwide including wheat, rice, maize, soybean, potato and others. Conventional resistance breeding strategies are hindered by the absence of tractable genetic resistance in any crop host. Understanding the biology and pathogenicity mechanisms of this fungus is important for addressing these disease issues, however, little is known about howR. solanicauses disease. This study capitalizes on recent genomic studies by applying mass spectrometry based proteomics to identify soluble, membrane-bound and culture filtrate proteins produced under wheat infection and vegetative growth conditions. Many of the proteins found in the culture filtrate had predicted functions relating to modification of the plant cell wall, a major activity required for pathogenesis on the plant host, including a number found only under infection conditions. Other infection related proteins included a high proportion of proteins with redox associated functions and many novel proteins without functional classification. The majority of infection only proteins tested were confirmed to show transcript up-regulation during infection including a thaumatin which increased susceptibility toR. solaniwhen expressed inNicotiana benthamiana In addition, analysis of expression during infection of different plant hosts highlighted how the infection strategy of this broad host range pathogen can be adapted to the particular host being encountered. Data are available via ProteomeXchange with identifier PXD002806.

  9. Chitosan-cinnamon beads enhance suppressive activity against Rhizoctonia solani and Meloidogyne incognita in vitro.

    PubMed

    Seo, Dong-Jun; Nguyen, Dang-Minh-Chanh; Park, Ro-Dong; Jung, Woo-Jin

    2014-01-01

    A novel chitosan-cinnamon bead carrier was prepared in this study. Chitosan was mixed with cinnamon powder (CP) and cinnamon extract (CE) to obtain chitosan-cinnamon powder (CCP) beads and chitosan-cinnamon extracted (CCE) beads, respectively. The potential antifungal and nematicidal activities of CCP and CCE were investigated against Rhizoctonia solani and Meloidogyne incognita in vitro. Relative antifungal activity of the CCP (5% CP) bead-treated R. solani was 30.9 and 23.9% after 1 and 2 day incubations, respectively. Relative antifungal activity of the CCE (0.5% CE) bead-treated R. solani was 4.3, 3.0 and 4.2% after 1, 2 and 3 days of incubation. Inhibition of hatch by CCP beads with CP of 5% was 78.8%. Inhibition of hatch by CCE beads with CE of 0.5% was 82.0%. J2 mortality following the CCP (5% CP) and CCE (0.5% CE) bead treatments was 85.0 and 95.8%, respectively against M. incognita after 48 h incubations.

  10. 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 μg/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.

  11. Development of controlled release nanoformulations of carbendazim employing amphiphilic polymers and their bioefficacy evaluation against Rhizoctonia solani.

    PubMed

    Koli, Pushpendra; Singh, Braj B; Shakil, Najam A; Kumar, Jitendra; Kamil, Deeba

    2015-01-01

    Controlled release nanoformulations of carbendazim (Methyl 1H-benzimidazol-2-ylcarbamate), a systemic fungicide, have been prepared using laboratory synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers. The release kinetics of carbendazim from developed controlled release (CR) formulations was studied and compared with that of the commercially available 50% Wettable Powder (WP). Further, the bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Rhizoctonia solani by the poison food technique method. The release of maximum amount of carbendazim from developed formulations was dependent on the molecular weight of PEGs and was found to increase with increasing molecular weights. The range of carbendazim release was found to be between 10th to 35th day as compared to commercial formulation which was up to 7th day. The diffusion exponent (n value) of carbendazim in water ranged from 0.37 to 0.52 in the tested formulations. The half-release (t1/2) values ranged between 9.47 and 24.20 days, and the period of optimum availability (POA) of carbendazim ranged from 9.15 to 26.63 days. Also, ED50 values of the developed formulations vary from 0.40 to 0.74 mg L(-1). These formulations can be used to optimize the release of carbendazim to achieve disease control for the desired period depending on the matrix of the polymer used.

  12. Genetic and genomic analysis of Rhizoctonia solani interactions with Arabidopsis; evidence of resistance mediated through NADPH oxidases.

    PubMed

    Foley, Rhonda C; Gleason, Cynthia A; Anderson, Jonathan P; Hamann, Thorsten; Singh, Karam B

    2013-01-01

    Rhizoctonia solani is an important soil-borne necrotrophic fungal pathogen, with a broad host range and little effective resistance in crop plants. Arabidopsis is resistant to R. solani AG8 but susceptible to R. solani AG2-1. A screen of 36 Arabidopsis ecotypes and mutants affected in the auxin, camalexin, salicylic acid, abscisic acid and ethylene/jasmonic acid pathways did not reveal any variation in response to R. solani and demonstrated that resistance to AG8 was independent of these defense pathways. The Arabidopsis Affymetrix ATH1 Genome array was used to assess global gene expression changes in plants infected with AG8 and AG2-1 at seven days post-infection. While there was considerable overlap in the response, some gene families were differentially affected by AG8 or AG2-1 and included those involved in oxidative stress, cell wall associated proteins, transcription factors and heat shock protein genes. Since a substantial proportion of the gene expression changes were associated with oxidative stress responses, we analysed the role of NADPH oxidases in resistance. While single NADPH oxidase mutants had no effect, a NADPH oxidase double mutant atrbohf atrbohd resulted in an almost complete loss of resistance to AG8, suggesting that reactive oxidative species play an important role in Arabidopsis's resistance to R. solani.

  13. Biocontrol of Rhizoctonia solani AG-2, the causal agent of damping-off by Muscodor cinnamomi CMU-Cib 461.

    PubMed

    Suwannarach, Nakarin; Kumla, Jaturong; Bussaban, Boonsom; Lumyong, Saisamorn

    2012-11-01

    Rhizoctonia solani is a damping-off pathogen that causes significant crop loss worldwide. In this study, the potential of Muscodor cinnamomi, a new species of endophytic fungus for controlling R. solani AG-2 damping-off disease of plant seedlings by biological fumigation was investigated. In vitro tests showed that M. cinnamomi volatile compounds inhibited mycelial growth of pathogens. Among nine solid media tested, rye grain was the best grain for inoculum production. An in vivo experiment of four seedlings, bird pepper, bush bean, garden pea and tomato were conducted. The results indicated that treatment with 30 g of M. cinnamomi inoculum was the minimum dose that caused complete control of damping-off symptoms of all seedlings after one month of planting. The R. solani-infested soil showed the lowest percentage of seed germination. In addition, M. cinnamomi did not cause any disease symptoms. From the results it is clear that M. cinnamomi is effective in controlling R. solani AG-2 both in vitro and in vivo.

  14. A novel mycovirus closely related to viruses in the genus Alphapartitivirus confers hypovirulence in the phytopathogenic fungus Rhizoctonia solani.

    PubMed

    Zheng, Li; Zhang, Meiling; Chen, Qiguang; Zhu, Minghai; Zhou, Erxun

    2014-05-01

    We report here the biological and molecular attributes of a novel dsRNA mycovirus designated Rhizoctonia solani partitivirus 2 (RsPV2) from strain GD-11 of R. solani AG-1 IA, the causal agent of rice sheath blight. The RsPV2 genome comprises two dsRNAs, each possessing a single ORF. Phylogenetic analyses indicated that this novel virus species RsPV2 showed a high sequence identity with the members of genus Alphapartitivirus in the family Partitiviridae, and formed a distinct clade distantly related to the other genera of Partitiviridae. Introduction of purified RsPV2 virus particles into protoplasts of a virus-free virulent strain GD-118 of R. solani AG-1 IA resulted in a derivative isogenic strain GD-118T with reduced mycelial growth and hypovirulence to rice leaves. Taken together, it is concluded that RsPV2 is a novel dsRNA virus belonging to Alphapartitivirus, with potential role in biological control of R. solani.

  15. Characterization of mycolytic enzymes of Bacillus strains and their bio-protection role against Rhizoctonia solani in tomato.

    PubMed

    Solanki, Manoj Kumar; Robert, Amrita Shalini; Singh, Rajesh Kumar; Kumar, Sudheer; Pandey, Akhilesh Kumar; Srivastava, Alok K; Arora, Dilip K

    2012-09-01

    Four antagonists bacteria namely, Bacillus megaterium MB3, B. subtilis MB14, B. subtilis MB99 and B. amyloliquefaciens MB101 were able to produce chitinase, β-1,3-glucanase and protease in different range with the presence of Rhizoctonia solani cell wall as a carbon source. Amplification of chitinase (chiA) gene of 270 bp and β-1, 3-glucanase gene of 415 bp was given supportive evidence at molecular level of antibiosis. After in vitro screening, all antagonists were tested against R. solani under greenhouse conditions. Root treatment of Bacillus strains showed superior defense during pathogen suppression in terms of chitinase, glucanase, peroxidase, poly phenol oxidase, phenylalanine ammonia-lyase activity and total phenolic content in leaves of tomato. All these enzymes accumulated high in tomato leaves as compared to roots. Pathogenesis-related proteins and defense-related enzymes accumulation was directly correlated with plant protection and greenhouse results indicated that B. amyloliquefaciens MB101- and B. subtilis MB14-treated plants offered 69.76 and 61.51 % disease reductions, respectively, over the infected control. These results established that these organisms have the potential to act as biocontrol agents. This study could be highlighted a mutual importance of liquid formulation of antagonistic Bacillus spp. against root associated sclerotia former pathogen R. solani.

  16. 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.

  17. iTRAQ-based proteomic analysis of defence responses triggered by the necrotrophic pathogen Rhizoctonia solani in cotton.

    PubMed

    Zhang, Min; Cheng, Shou-Ting; Wang, Hai-Yun; Wu, Jia-He; Luo, Yuan-Ming; Wang, Qian; Wang, Fu-Xin; Xia, Gui-Xian

    2017-01-30

    The soil-borne necrotrophic pathogen fungus Rhizoctonia solani is destructive, causing disease in various important crops. To date, little is known about the host defence mechanism in response to invasion of R. solani. Here, an iTRAQ-based proteomic analysis was employed to investigate pathogen-responsive proteins in the disease tolerant/resistant cotton cultivar CRI35. A total of 174 differentially accumulated proteins (DAPs) were identified after inoculation of cotton plants with R. solani. Functional categorization analysis indicated that these DAPs can be divided into 12 subclasses. Notably, a large portion of DAPs are known to function in reactive oxygen species (ROS) metabolism and the expression of several histone-modifying and DNA methylating proteins were significantly induced upon challenge with the fungus, indicating that the redox homeostasis and epigenetic regulation are important for cotton defence against the pathogen. Additionally, the expression of proteins involved in phenylpropanoid biosynthesis was markedly changed in response to pathogen invasion, which may reflect a particular contribution of secondary metabolism in protection against the fungal attack in cotton. Together, our results indicate that the defence response of cotton plants to R. solani infection is active and multifaceted and involves the induction of proteins from various innate immunity-related pathways.

  18. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat.

    PubMed

    Foley, Rhonda C; Kidd, Brendan N; Hane, James K; Anderson, Jonathan P; Singh, Karam B

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction.

  19. The adaptive potential of a plant pathogenic fungus, Rhizoctonia solani AG-3, under heat and fungicide stress.

    PubMed

    Willi, Yvonne; Frank, Aline; Heinzelmann, Renate; Kälin, Andrea; Spalinger, Lena; Ceresini, Paulo C

    2011-07-01

    The ability to improve fitness via adaptive evolution may be affected by environmental change. We tested this hypothesis in an in vitro experiment with the plant pathogen Rhizoctonia solani Anastomosis Group 3 (AG-3), assessing genetic and environmental variances under two temperatures (optimal and higher than optimal) and three fungicide concentrations (no fungicide, low and high concentration of a copper-based fungicide). We measured the mean daily growth rate, the coefficient of variation for genotypic (I (G)) and environmental variance (I (E)) in growth, and broad-sense heritability in growth. Both higher temperature and increased fungicide concentration caused a decline in growth, confirming their potential as stressors for the pathogen. All types of standardized variances in growth-I (G), phenotypic variance, and I (E) as a trend-increased with elevated stress. However, heritability was not significantly higher under enhanced stress because the increase in I (G) was counterbalanced by somewhat increased I (E). The results illustrate that predictions for adaptation under environmental stress may depend on the type of short-term evolvability measure. Because mycelial growth is linked to fitness, I (G) reflects short-term evolvability better than heritability, and it indicates that the evolutionary potential of R. solani is positively affected by stress.

  20. Enhanced production of phenazine-like metabolite produced by Streptomyces aurantiogriseus VSMGT1014 against rice pathogen, Rhizoctonia solani.

    PubMed

    Harikrishnan, Hariharan; Shanmugaiah, Vellasamy; Nithya, Karmegham; Balasubramanian, Natesan; Sharma, Mahaveer P; Gachomo, Emma W; Kotchoni, Simeon O

    2016-02-01

    The efficacy of a rhizobacterium Streptomyces aurantiogriseus VSMGT1014 for the production of bioactive metabolites with antifungal properties was evaluated under in vitro conditions. The production of bioactive metabolites by S. aurantiogriseus VSMGT1014 in International Streptomyces Project-2 (ISP-2) broth, supplemented with glucose and ammonium acetate was found to be the most suitable carbon and nitrogen sources for the maximum production of bioactive metabolites against rice pathogen, Rhizoctonia solani. The zone of inhibition range from 23.5 to 28.5 mm and 10.3 to 18.3 mm for glucose and ammonium acetate supplemented media, respectively. The culture filtrate of S. aurantiogriseus VSMGT1014 at pH 7.5, 37 °C at 120 rpm in 6 days of incubation showed the maximum production of bioactive metabolites with antagonistic potential. The crude metabolite was characterized by different spectral studies such as Ultraviolet spectrum, infrared-spectrum and based on the different analytical techniques, including thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with the retention time 29.4 and the bioactive metabolite was identified as phenazine, which was confirmed by pure phenazine compound as positive control.

  1. Isolation of mycoparasitic-related transcripts by SSH during interaction of the mycoparasite Stachybotrys elegans with its host Rhizoctonia solani.

    PubMed

    Morissette, Danielle C; Dauch, Amélie; Beech, Robin; Masson, Luke; Brousseau, Roland; Jabaji-Hare, Suha

    2008-02-01

    Mycoparasitism by antagonistic fungi involves changes in the biochemistry and physiology of both partners. Analysis of genes that are expressed during mycoparasite-host interaction represents a powerful strategy to obtain insight into the molecular events underlying these changes. The aim of this study is to identify genes whose expression is upregulated when the mycoparasite Stachybotrys elegans is in direct confrontation with its host Rhizoctonia solani. Suppression subtractive hybridization (SSH) was used to create a subtracted cDNA library, and differential screening was applied to identify the over-expressed transcripts. We report the analysis of 2,166 clones, among which 47% were upregulated during mycoparasitism. Two hundred and sixty-one clones were sequenced that corresponded to 94 unique genes. Forty-four of these were identified as novel genes, while the remainder showed similarity to a broad diversity of genes with putative functions related to toxin production, pathogenicity, and metabolism. As a result of mycoparasitism, 15 genes belonged to R. solani among which 9 genes were assigned putative functions. Quantitative RT-PCR was used to examine the upregulation of 12 genes during the course of mycoparasitism. Seven genes showed significant upregulation at least at one-time point during interaction of the mycoparasite with its host. This study describes a first step toward knowledge of S. elegans genome. The results present the useful application of EST analysis on S. elegans and provide preliminary indication of gene expression putatively involved in mycoparasitism.

  2. Induction of laccase activity in Rhizoctonia solani by antagonistic Pseudomonas fluorescens strains and a range of chemical treatments.

    PubMed

    Crowe, J D; Olsson, S

    2001-05-01

    Fungi often produce the phenoloxidase enzyme laccase during interactions with other organisms, an observation relevant to the development of biocontrols. By incorporating the laccase substrate 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into agar, we analyzed laccase induction in the plant-pathogenic fungus Rhizoctonia solani when paired against isolates of the soil bacterium Pseudomonas fluorescens. Substantial induction of R. solani laccase was seen only in pairings with strains of P. fluorescens known to produce antifungal metabolites. To study laccase induction further, a range of chemical treatments was applied to R. solani liquid cultures. p-Anisidine, copper(II), manganese(II), calcium ionophore A23187, lithium chloride, calcium chloride, cyclic AMP (cAMP), caffeine, amphotericin B, paraquat, ethanol, and isopropanol were all found to induce laccase; however, the P. fluorescens metabolite viscosinamide did not do so at the concentrations tested. The stress caused by these treatments was assessed by measuring changes in lipid peroxidation levels and dry weight. The results indicated that the laccase induction seen in pairing plate experiments was most likely due to calcium or heat shock signaling in response to the effects of bacterial metabolites, but that heavy metal and cAMP-driven laccase induction was involved in sclerotization.

  3. In vitro and in silico antifungal efficacy of nitrogen-doped carbon nanohorn (NCNH) against Rhizoctonia solani.

    PubMed

    Dharni, Seema; Sanchita; Unni, SreeKuttan M; Kurungot, Sreekumar; Samad, Abdul; Sharma, Ashok; Patra, Dharani Dhar

    2016-01-01

    We have investigated in vitro antifungal efficiency of nitrogen-doped carbon nanohorn (NCNH) against Rhizoctonia solani (R. solani) plant pathogenic fungi. NCNH with size of 50-60 nm and concentrations of 10, 50, 100, and 150 μg mL(-1) were used. The results showed that growth of fungi in the presence of NCNH was significantly (p > .05) inhibited at 150 μg mL(-1) (85.13 ± .97) after 72 h. The results were validated through computational approaches. Molecular docking analysis of NCNH with endochitinase protein of R. solani was performed to validate the potential of antifungal activity of NCNH. Docking results showed different conformations of interaction of NCNH with endochitinase enzyme. The conformation with least binding energy -13.54 kcal/mol was considered further. It is likely that NCNH interacts with the pathogens by mechanically wrapping, which may be one of the major toxicity actions of NCNH against R. solani. The analysis showed that NCNH might interwinds to endochitinase of R. solani leading to the deactivation of the enzyme. To best of our knowledge, this is the first report of antifungal efficacy of NCNH against R. solani and provides useful information about the application of NCNH in resisting crop disease.

  4. Induction of systemic resistance in rice by leaf extracts of Zizyphus jujuba and Ipomoea carnea against Rhizoctonia solani

    PubMed Central

    Marimuthu, Thambiayya; Kagale, Jayashree; Thayumanavan, Balsamy; Samiyappan, Ramasamy

    2011-01-01

    Plants accumulate a great diversity of natural products, many of which confer protective effects against phytopathogenic attack. Earlier we had demonstrated that the leaf extracts of Zizyphus jujuba and Ipomoea carnea inhibit the in vitro mycelial growth of Rhizoctonia solani, and effectively reduce the incidence of sheath blight disease in rice.7 Here we demonstrate that foliar application of the aqueous leaf extracts of Z. jujuba and I. carnea followed by challenge inoculation with R. solani induces systemic resistance in rice as evident from significantly increased accumulation of pathogenesis-related proteins such as chitinase, β-1,3-glucanase and peroxidase, as well as defense-related compounds such as phenylalanine ammonia-lyase and phenolic substances. Thin layer chromatographic separation of secondary metabolites revealed presence of alkaloid and terpenoid compounds in the leaf extracts of Z. jujuba that exhibited toxicity against R. solani under in vitro condition. Thus, the enhanced sheath blight resistance in rice seedlings treated with leaf extracts of Z. jujuba or I. carnea can be attributed to the direct inhibitory effects of these leaf extracts as well as their ability to elicit systemic resistance against R. solani. PMID:21593600

  5. 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

  6. 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.

  7. The Interaction Pattern between a Homology Model of 40S Ribosomal S9 Protein of Rhizoctonia solani and 1-Hydroxyphenaize by Docking Study

    PubMed Central

    Dharni, Seema; Sanchita; Sharma, Ashok; Patra, Dharani Dhar

    2014-01-01

    1-Hydroxyphenazine (1-OH-PHZ), a natural product from Pseudomonas aeruginosa strain SD12, was earlier reported to have potent antifungal activity against Rhizoctonia solani. In the present work, the antifungal activity of 1-OH-PHZ on 40S ribosomal S9 protein was validated by molecular docking approach. 1-OH-PHZ showed interaction with two polar contacts with residues, Arg69 and Phe19, which inhibits the synthesis of fungal protein. Our study reveals that 1-OH-PHZ can be a potent inhibitor of 40S ribosomal S9 protein of R. solani that may be a promising approach for the management of fungal diseases. PMID:24864254

  8. Solanioic Acid, an Antibacterial Degraded Steroid Produced in Culture by the Fungus Rhizoctonia solani Isolated from Tubers of the Medicinal Plant Cyperus rotundus.

    PubMed

    Ratnaweera, Pamoda B; Williams, David E; Patrick, Brian O; de Silva, E Dilip; Andersen, Raymond J

    2015-05-01

    Solanioic acid (1), a degraded and rearranged steroid that exhibits in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), has been isolated from laboratory cultures of the fungus Rhizoctonia solani obtained from tubers of the plant Cyperus rotundus collected in Sri Lanka. The structure of solanioic acid (1) was elucidated by detailed analysis of NMR data, a single crystal X-ray diffraction analysis of a reduction product 2, and Mosher ester analysis on a derivative of the natural product. Solanioic acid (1) has an unprecedented carbon skeleton.

  9. The interaction pattern between a homology model of 40S ribosomal S9 protein of Rhizoctonia solani and 1-hydroxyphenaize by docking study.

    PubMed

    Dharni, Seema; Sanchita; Samad, Abdul; Sharma, Ashok; Patra, Dharani Dhar

    2014-01-01

    1-Hydroxyphenazine (1-OH-PHZ), a natural product from Pseudomonas aeruginosa strain SD12, was earlier reported to have potent antifungal activity against Rhizoctonia solani. In the present work, the antifungal activity of 1-OH-PHZ on 40S ribosomal S9 protein was validated by molecular docking approach. 1-OH-PHZ showed interaction with two polar contacts with residues, Arg69 and Phe19, which inhibits the synthesis of fungal protein. Our study reveals that 1-OH-PHZ can be a potent inhibitor of 40S ribosomal S9 protein of R. solani that may be a promising approach for the management of fungal diseases.

  10. Characterization of antagonistic-potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato.

    PubMed

    Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K

    2015-01-01

    To investigate the biocontrol mechanism of two antagonistic Bacillus strains (Bacillus subtilis MB14 and Bacillus amyloliquefaciens MB101), three in vitro antagonism assays were screened and the results were concluded that both strains inhibited Rhizoctonia solani growth in a similar manner by dual culture assay, but the maximum percent of inhibition only resulted with MB101 by volatile and diffusible metabolite assays. Moreover, cell free supernatant (CFS) of MB101 also showed significant (p > 0.05) growth inhibition as compared to MB14, when 10 and 20% CFS mix with the growth medium of R. solani. After in vitro-validation, both strains were evaluated under greenhouse and the results concluded that strain MB101 had significant biocontrol potential as compared to MB14. Strain MB101 was enhanced the plant height, biomass and chlorophyll content of tomato plant through a higher degree of root colonization. In field trials, strain MB101 showed higher lessening in root rot symptoms with significant fruit yield as compare to strain MB14 and infected control. Next to the field study, the presence of four antibiotic genes (srfAA, fenD, ituC, and bmyB) also concluded the antifungal nature of both Bacillus strains. Phylogenetic analysis of protein sequences revealed a close relatedness of three genes (srfAA, fenD, and ituC) with earlier reported sequences of B. subtilis and B. amyloliquefaciens. However, bmyB showed heterogeneity in among both strains (MB14 and MB101) and it may be concluded that higher degree of antagonism, root colonization and different antibiotic producing genes may play an important role in biocontrol mechanism of strain MB101.

  11. Biocontrol of Rhizoctonia solani damping-off disease in cucumber with Bacillus pumilus SQR-N43.

    PubMed

    Huang, Xinqi; Zhang, Nan; Yong, Xiaoyu; Yang, Xingming; Shen, Qirong

    2012-03-20

    Biological control is an efficient and environmentally friendly way to prevent damping-off disease. Micrographs were used to investigate the ability of Bacillus pumilus (B. pumilus) SQR-N43 to control Rhizoctonia solani (R. solani) Q1 in cucumbers. The root colonization ability of B. pumilus SQR-N43 was analyzed in vivo with a green fluorescent protein (GFP) tag. A pot experiment was performed to assess the in vivo disease-control efficiency of B. pumilus SQR-N43 and its bio-organic fertilizer. Results indicate that B. pumilus SQR-N43 induced hyphal deformation, enlargement of cytoplasmic vacuoles and cytoplasmic leakage in R. solani Q1 mycelia. A biofilm on the root surface was formed when the roots were inoculated with 10(7)-10(8)cells g(-1) of soil of GFP-tagged B. pumilus SQR-N43. In the pot experiment, the biocontrol reduced the concentration of R. solani. In contrast to applications of only B. pumilus SQR-N43 (N treatment), which produced control efficiencies of 23%, control efficiencies of 68% were obtained with applications of a fermented organic fertilizer inoculated with B. pumilus SQR-N43 (BIO treatment). After twenty days of incubation, significant differences in the number of CFUs and the percentage of spores of B. pumilus SQR-N43 were recorded between the N treatment (2.20×10(7)CFU g(-1) of soil and 79%, respectively) and the BIO treatment (1.67×10(8)CFU g(-1) of soil and 52%, respectively). The results indicate that B. pumilus SQR-N43 is a potent antagonist against R. solani Q1. The BIO treatment was more effective than the N treatment because it stabilized the population and increased the active form of the antagonist.

  12. De novo Transcriptome Analysis of Rhizoctonia solani AG1 IA Strain Early Invasion in Zoysia japonica Root.

    PubMed

    Zhu, Chen; Ai, Lin; Wang, Li; Yin, Pingping; Liu, Chenglan; Li, Shanshan; Zeng, Huiming

    2016-01-01

    Zoysia japonica brown spot was caused by necrotrophic fungus Rhizoctonia solani invasion, which led to severe financial loss in city lawn and golf ground maintenance. However, little was known about the molecular mechanism of R. solani pathogenicity in Z. japonica. In this study we examined early stage interaction between R. solani AG1 IA strain and Z. japonica cultivar "Zenith" root by cell ultra-structure analysis, pathogenesis-related proteins assay and transcriptome analysis to explore molecular clues for AG1 IA strain pathogenicity in Z. japonica. No obvious cell structure damage was found in infected roots and most pathogenesis-related protein activities showedg a downward trend especially in 36 h post inoculation, which exhibits AG1 IA strain stealthy invasion characteristic. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database classification, most DEGs in infected "Zenith" roots dynamically changed especially in three aspects, signal transduction, gene translation, and protein synthesis. Total 3422 unigenes of "Zenith" root were predicted into 14 kinds of resistance (R) gene class. Potential fungal resistance related unigenes of "Zenith" root were involved in ligin biosynthesis, phytoalexin synthesis, oxidative burst, wax biosynthesis, while two down-regulated unigenes encoding leucine-rich repeat receptor protein kinase and subtilisin-like protease might be important for host-derived signal perception to AG1 IA strain invasion. According to Pathogen Host Interaction (PHI) database annotation, 1508 unigenes of AG1 IA strain were predicted and classified into 37 known pathogen species, in addition, unigenes encoding virulence, signaling, host stress tolerance, and potential effector were also predicted. This research uncovered transcriptional profiling during the early phase interaction between R. solani AG1 IA strain and Z. japonica, and will greatly help identify key pathogenicity of AG1 IA strain.

  13. De novo Transcriptome Analysis of Rhizoctonia solani AG1 IA Strain Early Invasion in Zoysia japonica Root

    PubMed Central

    Zhu, Chen; Ai, Lin; Wang, Li; Yin, Pingping; Liu, Chenglan; Li, Shanshan; Zeng, Huiming

    2016-01-01

    Zoysia japonica brown spot was caused by necrotrophic fungus Rhizoctonia solani invasion, which led to severe financial loss in city lawn and golf ground maintenance. However, little was known about the molecular mechanism of R. solani pathogenicity in Z. japonica. In this study we examined early stage interaction between R. solani AG1 IA strain and Z. japonica cultivar “Zenith” root by cell ultra-structure analysis, pathogenesis-related proteins assay and transcriptome analysis to explore molecular clues for AG1 IA strain pathogenicity in Z. japonica. No obvious cell structure damage was found in infected roots and most pathogenesis-related protein activities showedg a downward trend especially in 36 h post inoculation, which exhibits AG1 IA strain stealthy invasion characteristic. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database classification, most DEGs in infected “Zenith” roots dynamically changed especially in three aspects, signal transduction, gene translation, and protein synthesis. Total 3422 unigenes of “Zenith” root were predicted into 14 kinds of resistance (R) gene class. Potential fungal resistance related unigenes of “Zenith” root were involved in ligin biosynthesis, phytoalexin synthesis, oxidative burst, wax biosynthesis, while two down-regulated unigenes encoding leucine-rich repeat receptor protein kinase and subtilisin-like protease might be important for host-derived signal perception to AG1 IA strain invasion. According to Pathogen Host Interaction (PHI) database annotation, 1508 unigenes of AG1 IA strain were predicted and classified into 37 known pathogen species, in addition, unigenes encoding virulence, signaling, host stress tolerance, and potential effector were also predicted. This research uncovered transcriptional profiling during the early phase interaction between R. solani AG1 IA strain and Z. japonica, and will greatly help identify key pathogenicity of AG1 IA strain

  14. Molecular diversity analysis of Rhizoctonia solani isolates infecting various pulse crops in different agro-ecological regions of India.

    PubMed

    Dubey, Sunil C; Tripathi, Aradhika; Upadhyay, B K

    2012-11-01

    Genetic diversity of 89 isolates of Rhizoctonia solani isolated from different pulse crops representing 21 states from 16 agro-ecological regions of India, 49 morphological, and 7 anastomosis groups (AGs) was analyzed using 12 universal rice primers (URPs), 22 random amplified polymorphic DNA (RAPD), and 23 inter-simple sequence repeats (ISSR) markers. Both URPs and RAPD markers provided 100 % polymorphism with the bands ranging from 0.1 to 5 kb in size, whereas ISSR markers gave 99.7 % polymorphism with the bands sizes ranging from 0.1 to 3 kb. The marker URP 38F followed by URP13R, URP25F, and URP30F, RAPD marker R1 followed by OPM6, A3 and OPA12 and ISSR3 followed by ISSR1, ISSR4, and ISSR20 produced the highest number of amplicons. R. solani isolates showed a high level of genetic diversity. Unweighted pair group method with an arithmetic average (UPGMA) analysis grouped the isolates into 7 major clusters at 35 % genetic similarity using the three sets of markers evaluated. In spite of using three different types of markers, about 95 % isolates shared common grouping patterns. The majority of the isolates representing various AGs were grouped together into different sub-clusters using all three types of markers. Molecular groups of the isolates did not correspond to agro-ecological regions or states and crops of the origin. An attempt was made for the first time in the present study to determine the genetic diversity of R. solani populations isolated from different pulse crops representing various AGs and agro-ecological regions.

  15. Effects of Pseudomonas aureofaciens 63-28 on defense responses in soybean plants infected by Rhizoctonia solani.

    PubMed

    Jung, Woo-Jin; Park, Ro-Dong; Mabood, Fazli; Souleimanov, Alfred; L Smith, Donald

    2011-04-01

    The objective of this work was to investigate the ability of the plant growth-promoting rhizobacterium Pseudomonas aureofaciens 63-28 to induce plant defense systems, including defense-related enzyme levels and expression of defense-related isoenzymes, and isoflavone production, leading to improved resistance to the phytopathogen Rhizoctonia solani AG-4 in soybean seedlings. Seven-dayold soybean seedlings were inoculated with P. aureofaciens 63-28, R. solani AG-4, or P. aureofaciens 63-28 plus R. solani AG-4 (P+R), or not inoculated (control). After 7 days of incubation, roots treated with R. solani AG-4 had obvious damping-off symptoms, but P+R-treated soybean plants had less disease development, indicating suppression of R. solani AG-4 in soybean seedlings. Superoxide dismutase (SOD) and catalase (CAT) activities of R. solani AG-4-treated roots increased by 24.6% and 54.0%, respectively, compared with control roots. Ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) activities of R. solani AG-4-treated roots were increased by 75.1% and 23.6%, respectively. Polyphenol oxidase (PPO) activity in soybean roots challenged with P. aureofaciens 63-28 and P+R increased by 25.0% and 11.6%, respectively. Mn-SOD (S1 band on gel) and Fe-SOD (S2) were strongly induced in P+R-treated roots, whereas one CAT (C1) and one APX (A3) were strongly induced in R. solani AG-4- treated roots. The total isoflavone concentration in P+Rtreated shoots was 27.2% greater than the control treatment. The isoflavone yield of R. solani AG-4-treated shoots was 60.9% less than the control.

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

    PubMed

    Lakshman, Dilip K; Alkharouf, Nadim; Roberts, Daniel P; Natarajan, Savithiry S; Mitra, Amitava

    2012-01-01

    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. To get broad gene-expression coverage, two normalized EST libraries were developed from mycelia grown under high nitrogen-induced virulent and low nitrogen/methylglucose-induced hypovirulent conditions. A pilot-scale assessment of gene diversity was made from the sequence analyses of the two libraries. A total of 2280 cDNA clones was sequenced that corresponded to 220 unique sequence sets or clusters (contigs) and 805 singlets, making up a total of 1025 unique genes identified from the two virulence-differentiated cDNA libraries. From the total sequences, 295 genes (38.7%) exhibited strong similarities with genes in public databases and were categorized into 11 functional groups. Approximately 61.3% of the R. solani ESTs have no apparent homologs in publicly available fungal genome databases and are considered unique genes. We have identified several cDNAs with potential roles in fungal pathogenicity, virulence, signal transduction, vegetative incompatibility and mating, drug resistance, lignin degradation, bioremediation and morphological differentiation. A codon-usage table has been formulated based on 14694 R. solani EST codons. Further analysis of ESTs might provide insights into virulence mechanisms of R. solani AG 4 as well as roles of these genes in development, saprophytic colonization and ecological adaptation of this important fungal plant pathogen.

  17. Proteomic and genetic approaches to identifying defence-related proteins in rice challenged with the fungal pathogen Rhizoctonia solani.

    PubMed

    Lee, Joohyun; Bricker, Terry M; Lefevre, Michael; Pinson, Shannon R M; Oard, James H

    2006-09-01

    SUMMARY Sheath blight, caused by the fungus Rhizoctonia solani, is a major disease of rice world-wide, 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. solani. Replicated two-dimensional polyacrylamide gel electrophoresis experiments were conducted to detect proteins differentially expressed under inoculated and non-inoculated conditions. Tandem mass spectra analysis using electrospray ionization quadrupole-time of flight mass spectrometry (ESI Q-TOF MS) was carried out for protein identification with the NCBI non-redundant protein database. Seven proteins were increased after inoculation in both susceptible and resistant plants. Six of the seven proteins were identified with presumed antifungal, photosynthetic and proteolytic activities. An additional 14 proteins were detected in the response of the resistant line. Eleven of the 14 proteins were identified with presumed functions relating to antifungal activity, signal transduction, energy metabolism, photosynthesis, molecular chaperone, proteolysis and antioxidation. The induction of 3-beta-hydroxysteroid dehydrogenase/isomerase was detected for the first time in resistant rice plants after pathogen challenge, suggesting a defensive role of this enzyme in rice against attack by R. solani. The chromosomal locations of four induced proteins were found to be in close physical proximity to genetic markers for sheath blight resistance in two genetic mapping populations. The proteomic and genetic results from this study indicate a complex response of rice to challenge by R. solani that involves simultaneous induction of proteins from multiple defence pathways.

  18. 3-Methylthiopropionic Acid of Rhizoctonia solani AG-3 and Its Role in the Pathogenicity of the Fungus

    PubMed Central

    Kankam, Frederick; Long, Hai-Tao; He, Jing; Zhang, Chun-hong; Zhang, Hui-Xiu; Pu, Lumei; Qiu, Huizhen

    2016-01-01

    Studies were conducted to determine the role of 3-methylthioproprionic acid (MTPA) in the pathogenicity of potato stem canker, Rhizoctonia solani, and the concentrations required to inhibit growth of R. solani under laboratory and plant house-based conditions. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4, and 8 mM concentrations of MTPA. The purified toxin exhibited maximal activity at pH 2.5 and 30°C. MTPA at 1, 2, 4, and 8 mM levels reduced plant height, chlorophyll content, haulm fresh weight, number of stolons, canopy development, and tuber weight of potato plants, as compared to the control. MTPA significantly affected mycelial growth with 8 mM causing the highest infection. The potato seedlings treated with MTPA concentrations of 1.0–8.0 mM induced necrosis of up to 80% of root system area. Cankers were resulted from the injection of potato seedling stems with 8.0 mM MTPA. The results showed the disappearance of cell membrane, rough mitochondrial and cell walls, change of the shape of chloroplasts, and swollen endoplasmic reticulum. Seventy-six (76) hours after toxin treatment, cell contents were completely broken, cytoplasm dissolved, and more chromatin were seen in the nucleus. The results suggested that high levels of the toxin concentration caused cell membrane and cytoplasm fracture. The integrity of cellular structure was destroyed by the phytotoxin. The concentrations of the phytotoxin were significantly correlated with pathogenicity and caused damage to the cell membrane of potato stem base tissue. PMID:27147928

  19. Rapid and sensitive diagnoses of dry root rot pathogen of chickpea (Rhizoctonia bataticola (Taub.) Butler) using loop-mediated isothermal amplification assay

    PubMed Central

    Ghosh, Raju; Tarafdar, Avijit; Sharma, Mamta

    2017-01-01

    Dry root rot (DRR) caused by the fungus Rhizoctonia bataticola (Taub.) Butler, is an emerging disease in chickpea. The disease is often mistaken with other root rots like Fusarium wilt, collar rot and black root rot in chickpea. Therefore, its timely and specific detection is important. Current detection protocols are either based on mycological methods or on protocols involving DNA amplification by polymerase chain reaction (PCR). Here we report the rapid and specific detection of R. bataticola using loop-mediated isothermal amplification (LAMP) assay targeting fungal specific 5.8S rDNA sequence for visual detection of R. bataticola. The reaction was optimized at 63 °C for 75 min using minimum 10 fg of DNA. After adding SYBR Green I in LAMP products, the amplification was found to be highly specific in all the 94 isolates of R. bataticola collected from diverse geographical regions as well as DRR infected plants and sick soil. No reaction was found in other pathogenic fungi infecting chickpea (Fusarium oxysporum f. sp. ciceris, Rhizoctonia solani, Sclerotium rolfsii and Fusarium solani) and pigeonpea (Fusarium udum and Phytophthora cajani). The standardised LAMP assay with its simplicity, rapidity and specificity is very useful for the visual detection of this emerging disease in chickpea. PMID:28218268

  20. Identification of a novel mycovirus isolated from Rhizoctonia solani (AG 2-2 IV) provides further information about genome plasticity within the order Tymovirales.

    PubMed

    Bartholomäus, Anika; Wibberg, Daniel; Winkler, Anika; Pühler, Alfred; Schlüter, Andreas; Varrelmann, Mark

    2017-02-01

    The complete genome of a novel mycovirus, named Rhizoctonia solani flexivirus 1 (RsFV-1), which infects an avirulent strain of Rhizoctonia solani AG 2-2 IV, was sequenced and analyzed. Its RNA genome consists of 10,621 nucleotides, excluding the poly-A tail, and encodes a single protein of 3477 amino acids. The identification of conserved motifs of methyltransferase, helicase and RNA-dependent RNA polymerase revealed its relatedness to members of the alphavirus-like superfamily of positive-strand RNA viruses. Phylogenetic analysis of these fused domains suggested that this virus should be assigned to the order Tymovirales. The recently described Fusarium graminearum deltaflexivirus 1 was found to be its closest relative. However, the whole genome, as well as the encoded protein of RsFV-1, is larger than that of other known members of the order Tymovirales, and unlike all other viruses belonging to this order, its methyltransferase domain is not located at the N-terminus of the replicase. Although genome diversity, as a result of recombination and gene loss, is a well-documented trait in members of the order Tymovirales, no related virus with a comparable genome alteration has been reported before. For these reasons, RsFV-1 broadens our perception about genome plasticity and diversity within the order Tymovirales.

  1. Rapid and sensitive diagnoses of dry root rot pathogen of chickpea (Rhizoctonia bataticola (Taub.) Butler) using loop-mediated isothermal amplification assay.

    PubMed

    Ghosh, Raju; Tarafdar, Avijit; Sharma, Mamta

    2017-02-20

    Dry root rot (DRR) caused by the fungus Rhizoctonia bataticola (Taub.) Butler, is an emerging disease in chickpea. The disease is often mistaken with other root rots like Fusarium wilt, collar rot and black root rot in chickpea. Therefore, its timely and specific detection is important. Current detection protocols are either based on mycological methods or on protocols involving DNA amplification by polymerase chain reaction (PCR). Here we report the rapid and specific detection of R. bataticola using loop-mediated isothermal amplification (LAMP) assay targeting fungal specific 5.8S rDNA sequence for visual detection of R. bataticola. The reaction was optimized at 63 °C for 75 min using minimum 10 fg of DNA. After adding SYBR Green I in LAMP products, the amplification was found to be highly specific in all the 94 isolates of R. bataticola collected from diverse geographical regions as well as DRR infected plants and sick soil. No reaction was found in other pathogenic fungi infecting chickpea (Fusarium oxysporum f. sp. ciceris, Rhizoctonia solani, Sclerotium rolfsii and Fusarium solani) and pigeonpea (Fusarium udum and Phytophthora cajani). The standardised LAMP assay with its simplicity, rapidity and specificity is very useful for the visual detection of this emerging disease in chickpea.

  2. Effect of timing of glyphosate application to a winter wheat cover crop on stunting of spring-sown onions caused by Rhizoctonia spp. in the Columbia Basin of Washington, 2012.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of patches of stunted onion plants caused by Rhizoctonia spp. is an emerging problem in onion bulb crops planted in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Cereals such as winter wheat are used as cover crops to protect onion seedlin...

  3. Proteomic Investigation of Rhizoctonia solani AG 4 Identifies Secretome and Mycelial Proteins with Roles in Plant Cell Wall Degradation and Virulence.

    PubMed

    Lakshman, Dilip K; Roberts, Daniel P; Garrett, Wesley M; Natarajan, Savithiry S; Darwish, Omar; Alkharouf, Nadim; Pain, Arnab; Khan, Farooq; Jambhulkar, Prashant P; Mitra, Amitava

    2016-04-20

    Rhizoctonia solani AG 4 is a soilborne necrotrophic fungal plant pathogen that causes economically important diseases on agronomic crops worldwide. This study used a proteomics approach to characterize both intracellular proteins and the secretome of R. solani AG 4 isolate Rs23A under several growth conditions, the secretome being highly important in pathogenesis. From over 500 total secretome and soluble intracellular protein spots from 2-D gels, 457 protein spots were analyzed and 318 proteins positively matched with fungal proteins of known function by comparison with available R. solani genome databases specific for anastomosis groups 1-IA, 1-IB, and 3. These proteins were categorized to possible cellular locations and functional groups and for some proteins their putative roles in plant cell wall degradation and virulence. The majority of the secreted proteins were grouped to extracellular regions and contain hydrolase activity.

  4. The mechanism of antifungal action of a new polyene macrolide antibiotic antifungalmycin 702 from Streptomyces padanus JAU4234 on the rice sheath blight pathogen Rhizoctonia solani.

    PubMed

    Xiong, Zhi-Qiang; Tu, Xiao-Rong; Wei, Sai-Jin; Huang, Lin; Li, Xun-Hang; Lu, Hui; Tu, Guo-Quan

    2013-01-01

    Antifungalmycin 702, a new polyene macrolide antibiotic produced by Streptomycespadanus JAU4234, has a broad antifungal activity and may have potential future agricultural and/or clinical applications. However, the mechanism of antifungal action of antifungalmycin 702 remains unknown. Antifungalmycin 702 strongly inhibited mycelial growth and sclerotia formation/germination of Rhizoctonia solani. When treated with antifungalmycin 702, the hyphae morphology of R. solani became more irregular. The membrane and the cellular organelles were disrupted and there were many vacuoles in the cellular space. The lesion in the plasma membrane was detected through the increase of membrane permeability, lipid peroxidation and leakage of cell constituents. In summary, antifungalmycin 702 may exert its antifungal activity against R. solani by changing the structure of cell membranes and the cytoskeleton and interacting with the organelles.

  5. 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.

  6. Identification of two novel Rhizoctonia solani-inducible cis-acting elements in the promoter of the maize gene, GRMZM2G315431

    PubMed Central

    Li, Ning; Chen, Jing; Yang, Fangfang; Wei, Shutong; Kong, Lingguang; Ding, Xinhua; Chu, Zhaohui

    2017-01-01

    Plants are continuously exposed to myriad pathogen stresses. However, the molecular mechanisms by which these stress signals are perceived and transduced are poorly understood. In this study, the maize gene GRMZM2G315431 was identified to be highly inducible by Rhizoctonia solani infection, suggesting that the promoter of GRMZM2G315431 (pGRMZM2G315431) might contain a specific cis-acting element responsive to R. solani attack. To identify the R. solani-responsive element in pGRMZM2G315431, a series of binary plant transformation vectors were constructed by fusing pGRMZM2G315431 or its deletion-derivatives with the reporter genes. In the transient gene expression system of Nicotiana benthamiana leaves inoculated with R. solani, GUS quantification suggested that the DNA fragment contains the unknown pathogen-inducible cis-elements in the −1323 to −1212 region. Furthermore, detailed quantitative assays showed that two novel cis-elements, GTTGA in the −1243 to −1239 region and TATTT in the −1232 to −1228 region, were responsible for the R. solani-inducible activity. These two cis-elements were also identified to have R. solani-specific-inducible activity in stable transgenic rice plants, suggesting the existence of a novel regulation mechanism involved in the interaction between R. solani and Zea mays. PMID:28163300

  7. Effect of above-ground plant species on soil microbial community structure and its impact on suppression of Rhizoctonia solani AG3.

    PubMed

    Garbeva, P; Postma, J; van Veen, J A; van Elsas, J D

    2006-02-01

    The extent of soil microbial diversity is seen to be critical to the maintenance of soil health and quality. Different agricultural practices are able to affect soil microbial diversity and thus the level of suppressiveness of plant diseases. In a 4-year field experiment, we investigated the microbial diversity of soil under different agricultural regimes. We studied permanent grassland, grassland turned into arable land, long-term arable land and arable land turned into grassland. The diversity of microbial communities was described by using cultivation-based and cultivation-independent methods. Both types of methods revealed differences in the diversities of soil microbial communities between different treatments. The treatments with higher above-ground biodiversity generally maintained higher levels of microbial diversity. Moreover, a positive correlation between suppression of Rhizoctonia solani AG3 and microbial diversity was observed. Permanent (species-rich) grassland and grassland turned into maize stimulated higher microbial diversities and higher levels of suppressiveness of R. solani AG3 compared with the long-term arable land. Effects of agricultural practices on Bacillus and Pseudomonas communities were also observed and clear correlations between the levels of suppressiveness and the diversities of these bacterial groups were found. This study highlighted the importance of agricultural management regime for soil microbial community structure and diversity as well as the level of soil suppressiveness.

  8. Compositional variability and antifungal potentials of ocimum basilicum, O. tenuiflorum, O. gratissimum and O. kilimandscharicum essential oils against Rhizoctonia solani and Choanephora cucurbitarum.

    PubMed

    Padalia, Rajendra C; Verma, Ram S; Chauhan, Amit; Goswami, Prakash; Chanotiya, Chandan S; Saroj, Arvind; Samad, Abdul; Khaliq, Abdul

    2014-10-01

    The composition of hydrodistilled essential oils of Ocimum basilicum L. (four chemovariants), O. tenuiflorum L., O. gratissimum L., and O. kilimandscharicum Guerke were analyzed and compared by using capillary gas chromatography (GC/FID) and GC-mass spectrometry (GC/MS). Phenyl propanoids (upto 87.0%) and monoterpenoids (upto 83.3%) were prevalent constituents distributed in the studied Ocimum taxa. The major constituents of the four distinct chemovariants of O. basilicum were methyl chavicol (86.3%), methyl chavicol (61.5%)/linalool (28.6%), citral (65.9%); and linalool (36.1%)/citral (28.8%). Eugenol (66.5% and 78.0%) was the major constituent of O. tenuiflorum and O. gratissimum. Eugenol (34.0%), β-bisabolene (15.4%), (E)-α-bisabolene (10.9%), methyl chavicol (10.2%) and 1,8-cineole (8.2%) were the major constituents of O. kilimandscharicum. In order to explore the potential for industrial use, the extracted essential oils were assessed for their antifungal potential through poison food technique against two phytopathogens, Rhizoctonia solani and Choanephora cucurbitarum, which cause root and wet rot diseases in various crops. O. tenuiflorum, O. gratissimum, and O. kilimandscharicum exhibited complete growth inhibition against R. solani and C. cucurbitarum after 24 and 48 h of treatment. O. basilicum chemotypes showed variable levels of growth inhibition (63.0%-100%) against these two phytopathogens.

  9. 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

  10. Liquid culture production of microsclerotia and submerged conidia by Trichoderma harzianum active against damping-off disease caused by Rhizoctonia solani.

    PubMed

    Kobori, Nilce N; Mascarin, Gabriel M; Jackson, Mark A; Schisler, David A

    2015-04-01

    Media and culturing protocols were identified that supported the formation of submerged conidia and microsclerotia (MS) by Trichoderma harzianum Rifai strain T-22 using liquid culture fermentation. Liquid media with a higher carbon concentration (36 g L(-1)) promoted MS formation at all C:N ratios tested. Hyphae aggregated to form MS after 2 d growth and after 7 d MS were fully melanized. This is the first report of MS formation by T. harzianum or any species of Trichoderma. Furthermore, submerged conidia formation was induced by liquid culture media, but yields, desiccation tolerance, and storage stability varied with C:N ratio and carbon rate. Air-dried MS granules (<4% moisture) retained excellent shelf life under cool and unrefrigerated storage conditions with no loss in conidial production. A low-cost complex nitrogen source based on cottonseed flour effectively supported high MS yields. Amending potting mix with dried MS formulations reduced or eliminated damping-off of melon seedlings caused by Rhizoctonia solani. Together, the results provide insights into the liquid culture production, stabilization process, and bioefficacy of the hitherto unreported MS of T. harzianum as a potential biofungicide for use in integrated management programs against soilborne diseases.

  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. Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara.

    PubMed

    Goudjal, Yacine; Toumatia, Omrane; Yekkour, Amine; Sabaou, Nasserdine; Mathieu, Florence; Zitouni, Abdelghani

    2014-01-20

    Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomyces genus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activity against Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequently tested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils, and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seeds with antagonistic isolates significantly reduced (P<0.05) the severity of damping-off of tomato seedlings. Among the isolates tested, the strains CA-2 and AA-2 exhibited the same disease incidence reduction as thioperoxydicarbonic diamide, tetramethylthiram (TMTD) and no significant differences (P<0.05) were observed. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic position based on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 and AA-2 were related to Streptomyces mutabilis NBRC 12800(T) (100% of similarity) and Streptomyces cyaneofuscatus JCM 4364(T) (100% of similarity), respectively.

  13. Rice WRKY4 acts as a transcriptional activator mediating defense responses toward Rhizoctonia solani, the causing agent of rice sheath blight.

    PubMed

    Wang, Haihua; Meng, Jiao; Peng, Xixu; Tang, Xinke; Zhou, Pinglan; Xiang, Jianhua; Deng, Xiaobo

    2015-09-01

    WRKY transcription factors have been implicated in the regulation of transcriptional reprogramming associated with various plant processes but most notably with plant defense responses to pathogens. Here we demonstrate that expression of rice WRKY4 gene (OsWRKY4) was rapidly and strongly induced upon infection of Rhizoctonia solani, the causing agent of rice sheath blight, and exogenous jasmonic acid (JA) and ethylene (ET). OsWRKY4 is localized to the nucleus of plant cells and possesses transcriptional activation ability. Modulation of OsWRKY4 transcript levels by constitutive overexpression increases resistance to the necrotrophic sheath blight fungus, concomitant with elevated expression of JA- and ET-responsive pathogenesis-related (PR) genes such as PR1a, PR1b, PR5 and PR10/PBZ1. Suppression by RNA interference (RNAi), on the other hand, compromises resistance to the fungal pathogen. Yeast one-hybrid assay and transient expression in tobacco cells reveal that OsWRKY4 specifically binds to the promoter regions of PR1b and PR5 which contain W-box (TTGAC[C/T]), or W-box like (TGAC[C/T]) cis-elements. In conclusion, we propose that OsWRKY4 functions as an important positive regulator that is implicated in the defense responses to rice sheath blight via JA/ET-dependent signal pathway.

  14. Trichoderma harzianum ETS 323-mediated resistance in Brassica oleracea var. capitata to Rhizoctonia solani involves the novel expression of a glutathione S-transferase and a deoxycytidine deaminase.

    PubMed

    Shibu, Marthandam Asokan; Lin, Hong-Shin; Yang, Hsueh-Hui; Peng, Kou-Cheng

    2012-10-31

    Plant interactions with microbial biocontrol agents are used as experimental models to understand resistance-related molecular adaptations of plants. In a hydroponic three-way interaction study, a novel Trichoderma harzianum ETS 323 mediated mechanism was found to induce resistance to Rhizoctonia solani infection in Brassica oleracea var. capitata plantlets. The R. solani challenge on leaves initiate an increase in lipoxygenase activity and associated hypersensitive tissue damage with characteristic "programmed cell death" that facilitate the infection. However, B. oleracea plantlets whose roots were briefly (6 h) colonized by T. harzianum ETS 323 developed resistance to R. solani infection through a significant reduction of the host hypersensitive tissue damage. The resistance developed in the distal leaf tissue was associated with the expression of a H(2)O(2)-inducible glutathione S-transferase (BoGST), which scavenges cytotoxic reactive electrophiles, and of a deoxycytidine deaminase (BoDCD), which modulates the host molecular expression and potentially neutralizes the DNA adducts and maintains DNA integrity. The cDNAs of BoGST and BoDCD were cloned and sequenced; their expressions were verified by reverse-transcription polymerase chain reaction analysis and were found to be transcriptionally activated during the three-way interaction.

  15. Rice oxalate oxidase gene driven by green tissue-specific promoter increases tolerance to sheath blight pathogen (Rhizoctonia solani) in transgenic rice.

    PubMed

    Molla, Kutubuddin A; Karmakar, Subhasis; Chanda, Palas K; Ghosh, Satabdi; Sarkar, Sailendra N; Datta, Swapan K; Datta, Karabi

    2013-12-01

    Rice sheath blight, caused by the necrotrophic fungus Rhizoctonia solani, is one of the most devastating and intractable diseases of rice, leading to a significant reduction in rice productivity worldwide. In this article, in order to examine sheath blight resistance, we report the generation of transgenic rice lines overexpressing the rice oxalate oxidase 4 (Osoxo4) gene in a green tissue-specific manner which breaks down oxalic acid (OA), the pathogenesis factor secreted by R. solani. Transgenic plants showed higher enzyme activity of oxalate oxidase (OxO) than nontransgenic control plants, which was visualized by histochemical assays and sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Transgenic rice leaves were more tolerant than control rice leaves to exogenous OA. Transgenic plants showed a higher level of expression of other defence-related genes in response to pathogen infection. More importantly, transgenic plants exhibited significantly enhanced durable resistance to R. solani. The overexpression of Osoxo4 in rice did not show any detrimental phenotypic or agronomic effect. Our findings indicate that rice OxO can be utilized effectively in plant genetic manipulation for sheath blight resistance, and possibly for resistance to other diseases caused by necrotrophic fungi, especially those that secrete OA. This is the first report of the expression of defence genes in rice in a green tissue-specific manner for sheath blight resistance.

  16. Molecular characterization of the pathogenic plant fungus Rhizoctonia solani (Ceratobasidiaceae) isolated from Egypt based on protein and PCR-RAPD profiles.

    PubMed

    Mahmoud, M A; Al-Sohaibani, S A; Abdelbacki, A M M; Al-Othman, M R; Abd El-Aziz, A R M; Kasem, K K; Mikhail, M S; Sabet, K K; Omar, M R; Hussein, E M

    2012-10-04

    Twenty-one isolates of Rhizoctonia solani were categorized into three anastomosis groups consisting of AG-4-HG-I (eight isolates), AG-2-2 (nine isolates) and AG-5 (four isolates). Their pathogenic capacities were tested on cotton cultivar Giza 86. Pre-emergence damping-off varied in response to the different isolates; however, the differences were not significant. Soluble proteins of the fungal isolates were electrophoresed using SDS-PAGE and gel electrophoreses. A dendrogram of the protein banding patterns by the UPGMA of arithmetic means placed the fungal isolates into distinct groups. There was no evidence of a relationship between protein dendrogram, anastomosis grouping or level of virulence or geographic origin. The dendrogram generated from these isolates based on PCR analysis with five RAPD-PCR primers showed high levels of genetic similarity among the isolates from the same geographical locations. There was partially relationship between the genetic similarity and AGs or level of virulence or geographic origin based on RAPD dendrogram. These results demonstrate that RAPD technique is a useful tool in determining the genetic characterization among isolates of R. solani.

  17. 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.

  18. Transcriptome analysis of the phytopathogenic fungus Rhizoctonia solani AG1-IB 7/3/14 applying high-throughput sequencing of expressed sequence tags (ESTs).

    PubMed

    Wibberg, Daniel; Jelonek, Lukas; Rupp, Oliver; Kröber, Magdalena; Goesmann, Alexander; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2014-01-01

    Rhizoctonia solani is a soil-borne plant pathogenic fungus of the phylum Basidiomycota. It affects a wide range of agriculturally important crops and hence is responsible for economically relevant crop losses. Transcriptome analysis of the bottom rot pathogen R. solani AG1-1B (isolate 7/3/14) by applying high-throughput sequencing and bioinformatics methods addressing Expressed Sequence Tag (EST) data interpretation provided new insights in expressed genes of this fungus. Two normalized cDNA libraries representing different cultivation conditions of the fungus were sequenced on the 454 FLX (Roche) system. Subsequent to cDNA sequence assembly and quality control, ESTs were analysed applying advanced bioinformatics methods. More than 14 000 transcript isoforms originating from approximately 10 000 predictable R. solani AG1-IB 7/3/14 genes are represented in each dataset. Comparative analyses revealed several differentially expressed genes depending on the growth conditions applied. Determinants with predicted functions in recognition processes between the fungus and the host plant were identified. Moreover, many R. solani AG1-IB ESTs were predicted to encode putative cellulose, pectin, and lignin degrading enzymes. Furthermore, genes playing a possible role in mitogen-activated protein (MAP) kinase cascades, 4-aminobutyric acid (GABA) metabolism, melanin synthesis, plant defence antagonism, phytotoxin, and mycotoxin synthesis were detected.

  19. 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 μl⁻¹ of genomic DNA; and that of the ITS-Mp-LAMP assay was 100 pg μl⁻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.

  20. Chitinolytic Streptomyces vinaceusdrappus S5MW2 isolated from Chilika lake, India enhances plant growth and biocontrol efficacy through chitin supplementation against Rhizoctonia solani.

    PubMed

    Yandigeri, Mahesh S; Malviya, Nityanand; Solanki, Manoj Kumar; Shrivastava, Pooja; Sivakumar, G

    2015-08-01

    A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance.

  1. Monomeric L-amino acid oxidase-induced mitochondrial dysfunction in Rhizoctonia solani Reveals a novel antagonistic mechanism of Trichoderma harzianum ETS 323.

    PubMed

    Yang, Chia-Ann; Cheng, Chi-Hua; Lee, Jeng-Woei; Lo, Chaur-Tsuen; Liu, Shu-Ying; Peng, Kou-Cheng

    2012-03-14

    The monomeric L-amino acid oxidase (mTh-LAAO) of Trichoderma harzianum ETS 323 has been suggested to antagonize Rhizoctonia solani by an unknown mechanism. Here, the mTh-LAAO-treated R. solani exhibited hyphal lysis and apoptotic characteristics such as DNA fragmentation, reactive oxygen species (ROS) accumulation, lipid peroxidation, and mitochondrial membrane potential depolarization. This hyphal lysis was suppressed by the mitochondria-dependent apoptosis inhibitor oligomycin while accompanied by reduction of ROS accumulation. This result suggested that mitochondria-mediated apoptosis in R. solani was involved in mTh-LAAO-induced growth inhibition, which was supported by the evidence of cytocheome c release and activation of caspases 9 and 3. Furthermore, the data indicated that the mTh-LAAO-induced fungal cell death was also closely interrelated with the interaction of mTh-LAAO with R. solani hyphal cell wall proteins. These results illuminate the biological function and mechanism underlying the antagonistic action of T. harzianum mTh-LAAO against fungal pathogens.

  2. Two distinct classes of protein related to GTB and RRM are critical in the sclerotial metamorphosis process of Rhizoctonia solani AG-1 IA.

    PubMed

    Shu, Canwei; Chen, Jieling; Sun, Si; Zhang, Meiling; Wang, Chenjiaozi; Zhou, Erxun

    2015-07-01

    Sheath blight of rice, caused by Rhizoctonia solani Kühn AG-1 IA [teleomorph: Thanatephorus cucumeris (Frank) Donk], is one of the major diseases of rice (Oryza sativa L.) worldwide. Sclerotia produced by R. solani AG-1 IA are crucial for their survival in adverse environments and further dissemination when environmental conditions become conducive. Differentially expressed genes during three stages of sclerotial metamorphosis of R. solani AG-1 IA were investigated by utilizing complementary DNA amplified fragment length polymorphism (cDNA-AFLP) technique. A total of 258 transcript derived fragments (TDFs) were obtained and sequenced, among which 253 TDFs were annotated with known functions through BLASTX by searching the GenBank database and 19 annotated TDFs were assigned into 19 secondary metabolic pathways through searching the Kyoto Encyclopedia of Genes and Genomes (KEGG) PATHWAY database. Moreover, the results of quantitative real-time PCR (qRT-PCR) analysis showed that the expression patterns of eight representative annotated TDFs were positively correlated with sclerotial metamorphosis. Sequence annotation of TDFs showed homology similarities to several genes encoding for proteins belonging to the glycosyltransferases B (GTB) and RNA recognition motif (RRM) superfamily and to other development-related proteins. Taken together, it is concluded that the members of the GTB and RRM superfamilies and several new genes involved in proteolytic process identified in this study might serve as the scavengers of free radicals and reactive oxygen species (ROS) and thus play an important role in the sclerotial metamorphosis process of R. solani AG-1 IA.

  3. Identification of phenazine-1-carboxylic acid gene (phc CD) from Bacillus pumilus MTCC7615 and its role in antagonism against Rhizoctonia solani.

    PubMed

    Padaria, Jasdeep Chatrath; Tarafdar, Avijit; Raipuria, Rajkumar; Lone, Showkat Ahmad; Gahlot, Pallavi; Shakil, Najam A; Kumar, Jitendra

    2016-09-01

    Bacillus pumilus MTCC7615, a biocontrol agent isolated from rice rhizosphere was characterized to be antagonistic to Rhizoctonia solani, the pathogen causing sheath blight disease of rice. The phenazine-1-carboxylic acid gene (phc CD) of this bacterium was PCR amplified (1400 bp), cloned, and sequenced. The sequence analysis revealed the presence of two ORFs of phc CD gene commonly found in Pseudomonas species. The sequence showed 98% similarity to phc CD gene of the Pseudomonas isolate LBUM223 (DQ788993). The crude antibiotic extract from B. pumilus MTCC7615 was observed to inhibit mycelial growth of R. solani under in vitro conditions. The HPLC analysis of crude antibiotic extract from B. pumilus MTCC7615 confirmed the presence of phenazine. The study has also reported the presence of phc CD gene which is responsible for the synthesis of phenazine-1-carboxylic acid in B. pumilus. The ability of the bacterial isolate to control sheath blight disease in rice seedlings under in vivo conditions was confirmed by the pot culture experiment. The structural and functional genomics of phc C and phc D genes would lead to a better understanding of phenazine biosynthesis in B. pumilus for its efficient utilization in plant protection strategies.

  4. Characterization of genes involved in biosynthesis of a novel antibiotic from Burkholderia cepacia BC11 and their role in biological control of Rhizoctonia solani

    SciTech Connect

    Kang, Y.; Carlson, R.; Tharpe, W.; Schell, M.A.

    1998-10-01

    Genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. Burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. Here the authors report genetic and biochemical characterization of a soil isolate of B. cepacia relating to its production of an unusual antibiotic that is very active against a variety of soil fungi. Purification and preliminary structural analyses suggest that this antibiotic (called AFC-BC11) is a novel lipopeptide associated largely with the cell membrane. Analysis of conditions for optimal production of AFC-BC11 indicated stringent environmental regulation of its synthesis. Furthermore, the authors show that production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11 to effectively control the damping-Off of cotton caused by the fungal pathogen Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, they identified, cloned, and characterized a region of the genome of strain BC11 that is required for production of this antifungal metabolite. DNA sequence analysis suggested that this region encodes proteins directly involved in the production of a nonribosomally synthesized lipopeptide.

  5. Enrichment of perforate septal pore caps from the basidiomycetous fungus Rhizoctonia solani by combined use of French press, isopycnic centrifugation, and Triton X-100.

    PubMed

    van Driel, Kenneth G A; van Peer, Arend F; Wösten, Han A B; Verkleij, Arie J; Boekhout, Teun; Müller, Wally H

    2007-12-01

    Septal pore caps occur in many filamentous basidiomycetes located at both sides of the dolipore septum and are at their base connected to the endoplasmic reticulum. The septal pore cap ultrastructure has been described extensively by the use of electron microscopy, but its composition and function are not yet known. To enable biochemical and functional analyses in the future, we here describe an enrichment method for perforate septal pore caps from Rhizoctonia solani. Our method is based on the combined use of French press and isopycnic centrifugation, using a discontinuous sucrose gradient followed by a treatment with Triton X-100. Enrichment was monitored by the use of scanning electron microscopy and transmission electron microscopy. Using the same isolation method, smaller septal pore caps were isolated from two other basidiomycetes as well. Furthermore, we showed pore-occluding material co-purified with the septal pore caps. This observation supports the hypothesis that septal pore caps play a key role in the plugging process of the septal pores in filamentous basidiomycetes.

  6. 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

    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.

  7. The wheat R2R3-MYB transcription factor TaRIM1 participates in resistance response against the pathogen Rhizoctonia cerealis infection through regulating defense genes

    PubMed Central

    Shan, Tianlei; Rong, Wei; Xu, Huijun; Du, Lipu; Liu, Xin; Zhang, Zengyan

    2016-01-01

    The necrotrophic fungus Rhizoctonia cerealis is a major pathogen of sharp eyespot that is a devastating disease of wheat (Triticum aestivum). Little is known about roles of MYB genes in wheat defense response to R. cerealis. In this study, TaRIM1, a R. cerealis-induced wheat MYB gene, was identified by transcriptome analysis, then cloned from resistant wheat CI12633, and its function and preliminary mechanism were studied. Sequence analysis showed that TaRIM1 encodes a R2R3-MYB transcription factor with transcription-activation activity. The molecular-biological assays revealed that the TaRIM1 protein localizes to nuclear and can bind to five MYB-binding site cis-elements. Functional dissection results showed that following R. cerealis inoculation, TaRIM1 silencing impaired the resistance of wheat CI12633, whereas TaRIM1 overexpression significantly increased resistance of transgenic wheat compared with susceptible recipient. TaRIM1 positively regulated the expression of five defense genes (Defensin, PR10, PR17c, nsLTP1, and chitinase1) possibly through binding to MYB-binding sites in their promoters. These results suggest that the R2R3-MYB transcription factor TaRIM1 positively regulates resistance response to R. cerealis infection through modulating the expression of a range of defense genes, and that TaRIM1 is a candidate gene to improve sharp eyespot resistance in wheat. PMID:27364458

  8. Identification of anastomosis group of Rhizoctonia solani, the causal agent of seed rot and damping-off of bean in Iran.

    PubMed

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

    2005-01-01

    Bean is one of the major crops in Iran. Seed rot and damping-off caused by Rhizoctonia solani is the most important disease of bean. In this research, infected roots and seedlings of beans were collected from different fields of Tehran Province. The samples were sterilized with 10% sodium hypochloride (5% stock) and incubated on PDA surface in petri-dishes. The purified fungi kept on filter paper and identified, pathogenicity test of R. solani was carried out on 2 cultivars of bean (red bean cv. Naz and white bean cv. Dehghan) and it determined. For identification of the anastomosis groups, the discs of cultured media with 5 mm. diameter of standard AG placed on one side of microscopic slides covered with water agar (2%) of 1 mm. thick and the isolates of the fungus on another side of slide about 2 cm away from each other. Experiment carried out in 4 replications. The cultures were incubated in 25 +/- 1 degrees C incubator for 24 hours, then the mycelial contact stained with lactophenol, cotton blue and hyphal anastomosis looked for under the light microscope with 10 x 40 and 10 x 100 magnifications. As a result, anastomosis groups: AG4, AG4HGII, AG2-2-2B and AG6 determined, frequency of these groups were 64, 18, 2, 16%, respectively. The group AG6 and subgroups AG4HGII and AG2-2-2B are introduced as new anastomosis groups on bean in Iran.

  9. Trichoderma harzianum strain SQR-T37 and its bio-organic fertilizer could control Rhizoctonia solani damping-off disease in cucumber seedlings mainly by the mycoparasitism.

    PubMed

    Huang, Xinqi; Chen, Lihua; Ran, Wei; Shen, Qirong; Yang, Xingming

    2011-08-01

    Damping-off disease is caused by Rhizoctonia solani and leads to serious loss in many crops. Biological control is an efficient and environmentally friendly way to prevent damping-off disease. Optical micrographs, scanning electron micrographs, and the determination of hydrolytic enzymes were used to investigate the antagonism of Trichoderma harzianum SQR-T37 (SQR-T37) against R. solani. Experiments were performed in pots to assess the in vivo disease-control efficiency of SQR-T37 and bio-organic fertilizer. The results indicate that the mycoparasitism was the main mechanism accounting for the antagonistic activity of SQR-T37. In one experiment, the population of R. solani was decreased from 10(6) internal transcribed spacer (ITS) copies per gram soil to 10(4) ITS copies per gram soil by the presence of the antagonist. In this experiment, 45% of the control efficiency was obtained when 8 g of SQR-T37 hyphae per gram soil was applied. In a second experiment, as much as 81.82% of the control efficiency was obtained when bio-organic fertilizer (SQR-T37 fermented organic fertilizer, BIO) was applied compared to only 27.27% of the control efficiency when only 4 g of SQR-T37 hyphae per gram soil was applied. Twenty days after incubation, the population of T. harzianum was 4.12 × 10(7) ITS copies per gram soil in the BIO treatment, which was much higher than that in the previous treatment (8.77 × 10(5) ITS copies per gram soil), where only SQR-T37 was applied. The results indicated that SQR-T37 was a potent antagonist against R. solani in a mycoparasitic way that decreased the population of the pathogen. Applying BIO was more efficient than SQR-T37 application alone because it stabilized the population of the antagonist.

  10. Development of a qPCR Strategy to Select Bean Genes Involved in Plant Defense Response and Regulated by the Trichoderma velutinum - Rhizoctonia solani Interaction.

    PubMed

    Mayo, Sara; Cominelli, Eleonora; Sparvoli, Francesca; González-López, Oscar; Rodríguez-González, Alvaro; Gutiérrez, Santiago; Casquero, Pedro A

    2016-01-01

    Bean production is affected by a wide diversity of fungal pathogens, among them Rhizoctonia solani is one of the most important. A strategy to control bean infectious diseases, mainly those caused by fungi, is based on the use of biocontrol agents (BCAs) that can reduce the negative effects of plant pathogens and also can promote positive responses in the plant. Trichoderma is a fungal genus that is able to induce the expression of genes involved in plant defense response and also to promote plant growth, root development and nutrient uptake. In this article, a strategy that combines in silico analysis and real time PCR to detect additional bean defense-related genes, regulated by the presence of Trichoderma velutinum and/or R. solani has been applied. Based in this strategy, from the 48 bean genes initially analyzed, 14 were selected, and only WRKY33, CH5b and hGS showed an up-regulatory response in the presence of T. velutinum. The other genes were or not affected (OSM34) or down-regulated by the presence of this fungus. R. solani infection resulted in a down-regulation of most of the genes analyzed, except PR1, OSM34 and CNGC2 that were not affected, and the presence of both, T. velutinum and R. solani, up-regulates hGS and down-regulates all the other genes analyzed, except CH5b which was not significantly affected. As conclusion, the strategy described in the present work has been shown to be effective to detect genes involved in plant defense, which respond to the presence of a BCA or to a pathogen and also to the presence of both. The selected genes show significant homology with previously described plant defense genes and they are expressed in bean leaves of plants treated with T. velutinum and/or infected with R. solani.

  11. 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.

  12. 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.

  13. Hyphae-colonizing Burkholderia sp.--a new source of biological control agents against sheath blight disease (Rhizoctonia solani AG1-IA) in rice.

    PubMed

    Cuong, Nguyen Duc; Nicolaisen, Mette Haubjerg; Sørensen, Jan; Olsson, Stefan

    2011-08-01

    Sheath blight infection of rice by Rhizoctonia solani Kühn AG1-IA often results in serious yield losses in intensive rice cultivation. Biological control agents (BCAs) have previously been isolated but poor efficiency is often observed when applied under field conditions. This study compares a traditional dual-culture plate assay and a new water-surface microcosm assay for isolation of antagonistic soil bacteria. In the water-surface microcosm assay, floating pathogen mycelium is used as a source for isolation of hyphae-colonizing soil bacteria (HCSB), which are subsequently screened for antagonism. Ten antagonistic soil bacteria (ASB) isolated from a variety of Vietnamese rice soils using dual-culture plates were found to be affiliated with Bacillus based on 16S rRNA gene sequencing. However, all the ASB isolates grew poorly and showed no antagonism in the water-surface microcosm assay. In contrast, 11 (out of 13) HCSB isolates affiliated with Burkholderia sp. all grew well by colonizing the hyphae in the microcosms. Two of the Burkholderia sp. isolates, assigned to B. vietnamiensis based on recA gene sequencing, strongly inhibited fungal growth in both the dual-culture and water-surface microcosm assays; HCSB isolates affiliated to other species or species groups showed limited or no inhibition of R. solani in the microcosms. Our results suggest that HCSB obtained from floating pathogen hyphae can be a new source for isolation of efficient BCAs against R. solani, as the isolation assay mimics the natural habitat for fungal-bacterial interaction in the fields.

  14. The wheat NB-LRR gene TaRCR1 is required for host defence response to the necrotrophic fungal pathogen Rhizoctonia cerealis.

    PubMed

    Zhu, Xiuliang; Lu, Chungui; Du, Lipu; Ye, Xingguo; Liu, Xin; Coules, Anne; Zhang, Zengyan

    2016-11-18

    The necrotrophic fungus Rhizoctonia cerealis is the major pathogen causing sharp eyespot disease in wheat (Triticum aestivum). Nucleotide-binding leucine-rich repeat (NB-LRR) proteins often mediate plant disease resistance to biotrophic pathogens. Little is known about the role of NB-LRR genes involved in wheat response to R. cerealis. In this study, a wheat NB-LRR gene, named TaRCR1, was identified in response to R. cerealis infection using Artificial Neural Network analysis based on comparative transcriptomics and its defence role was characterized. The transcriptional level of TaRCR1 was enhanced after R. cerealis inoculation and associated with the resistance level of wheat. TaRCR1 was located on wheat chromosome 3BS and encoded an NB-LRR protein that was consisting of a coiled-coil domain, an NB-ARC domain and 13 imperfect leucine-rich repeats. TaRCR1 was localized in both the cytoplasm and the nucleus. Silencing of TaRCR1 impaired wheat resistance to R. cerealis, whereas TaRCR1 overexpression significantly increased the resistance in transgenic wheat. TaRCR1 regulated certain reactive oxygen species (ROS)-scavenging and production, and defence-related genes, and peroxidase activity. Furthermore, H2 O2 pretreatment for 12-h elevated expression levels of TaRCR1 and the above defence-related genes, whereas treatment with a peroxidase inhibitor for 12 h reduced the resistance of TaRCR1-overexpressing transgenic plants and expression levels of these defence-related genes. Taken together, TaRCR1 positively contributes to defence response to R. cerealis through maintaining ROS homoeostasis and regulating the expression of defence-related genes.

  15. Genes of the de novo and Salvage Biosynthesis Pathways of Vitamin B6 are Regulated under Oxidative Stress in the Plant Pathogen Rhizoctonia solani

    PubMed Central

    Samsatly, Jamil; Chamoun, Rony; Gluck-Thaler, Emile; Jabaji, Suha

    2016-01-01

    Vitamin B6 is recognized as an important cofactor required for numerous metabolic enzymes, and has been shown to act as an antioxidant and play a role in stress responses. It can be synthesized through two different routes: salvage and de novo pathways. However, little is known about the possible function of the vitamin B6 pathways in the fungal plant pathogen Rhizoctonia solani. Using genome walking, the de novo biosynthetic pathway genes; RsolPDX1 and RsolPDX2 and the salvage biosynthetic pathway gene, RsolPLR were sequenced. The predicted amino acid sequences of the three genes had high degrees of similarity to other fungal PDX1, PDX2, and PLR proteins and are closely related to other R. solani anastomosis groups. We also examined their regulation when subjected to reactive oxygen species (ROS) stress inducers, the superoxide generator paraquat, or H2O2, and compared it to the well-known antioxidant genes, catalase and glutathione-S-transferase (GST). The genes were differentially regulated with transcript levels as high as 33 fold depending on the gene and type of stress reflecting differences in the type of damage induced by ROS. Exogenous addition of the vitamers PN or PLP in culture medium significantly induced the transcription of the vitamin B6 de novo encoding genes as early as 0.5 hour post treatment (HPT). On the other hand, transcription of RsolPLR was vitamer-specific; a down regulation upon supplementation of PN and upregulation with PLP. Our results suggest that accumulation of ROS in R. solani mycelia is linked to transcriptional regulation of the three genes and implicate the vitamin B6 biosynthesis machinery in R. solani, similar to catalases and GST, as an antioxidant stress protector against oxidative stress. PMID:26779127

  16. Modulation of the phenylacetic acid metabolic complex by quinic acid alters the disease-causing activity of Rhizoctonia solani on tomato.

    PubMed

    Bartz, Faith E; Glassbrook, Norman J; Danehower, David A; Cubeta, Marc A

    2013-05-01

    The metabolic control of plant growth regulator production by the plant pathogenic fungus Rhizoctonia solani Kühn (teleomorph=Thanatephorus cucumeris (A.B. Frank) Donk) and consequences associated with the parasitic and saprobic activity of the fungus were investigated. Fourteen genetically distinct isolates of the fungus belonging to anastomosis groups (AG) AG-3, AG-4, and AG-1-IA were grown on Vogel's minimal medium N with and without the addition of a 25 mM quinic acid (QA) source of carbon. The effect of QA on fungal biomass was determined by measuring the dry wt of mycelia produced under each growth condition. QA stimulated growth of 13 of 14 isolates of R. solani examined. The production of phenylacetic acid (PAA) and the chemically related derivatives 2-hydroxy-PAA, 3-hydroxy-PAA, 4-hydroxy-PAA, and 3-methoxy-PAA on the two different media was compared by gas chromatography coupled with mass spectrometry (GC-MS). The presence of QA in the growth medium of R. solani altered the PAA production profile, limiting the conversion of PAA to derivative forms. The effect of QA on the ability of R. solani to cause disease was examined by inoculating tomato (Solanum lycopersicum L.) plants with 11 isolates of R. solani AG-3 grown on media with and without the addition of 25 mM QA. Mean percent survival of tomato plants inoculated with R. solani was significantly higher when the fungal inoculum was generated on growth medium containing QA. The results of this study support the hypotheses that utilization of QA by R. solani leads to reduced production of the plant growth regulators belonging to the PAA metabolic complex which can suppress plant disease development.

  17. Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.

    PubMed

    Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi

    2015-02-01

    The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants Δbac, Δsrf, and Δsrf + bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant Δbac, not Δsrf or Δsrf + bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 μg/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 μg/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization.

  18. 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.

  19. Development of a qPCR Strategy to Select Bean Genes Involved in Plant Defense Response and Regulated by the Trichoderma velutinum – Rhizoctonia solani Interaction

    PubMed Central

    Mayo, Sara; Cominelli, Eleonora; Sparvoli, Francesca; González-López, Oscar; Rodríguez-González, Alvaro; Gutiérrez, Santiago; Casquero, Pedro A.

    2016-01-01

    Bean production is affected by a wide diversity of fungal pathogens, among them Rhizoctonia solani is one of the most important. A strategy to control bean infectious diseases, mainly those caused by fungi, is based on the use of biocontrol agents (BCAs) that can reduce the negative effects of plant pathogens and also can promote positive responses in the plant. Trichoderma is a fungal genus that is able to induce the expression of genes involved in plant defense response and also to promote plant growth, root development and nutrient uptake. In this article, a strategy that combines in silico analysis and real time PCR to detect additional bean defense-related genes, regulated by the presence of Trichoderma velutinum and/or R. solani has been applied. Based in this strategy, from the 48 bean genes initially analyzed, 14 were selected, and only WRKY33, CH5b and hGS showed an up-regulatory response in the presence of T. velutinum. The other genes were or not affected (OSM34) or down-regulated by the presence of this fungus. R. solani infection resulted in a down-regulation of most of the genes analyzed, except PR1, OSM34 and CNGC2 that were not affected, and the presence of both, T. velutinum and R. solani, up-regulates hGS and down-regulates all the other genes analyzed, except CH5b which was not significantly affected. As conclusion, the strategy described in the present work has been shown to be effective to detect genes involved in plant defense, which respond to the presence of a BCA or to a pathogen and also to the presence of both. The selected genes show significant homology with previously described plant defense genes and they are expressed in bean leaves of plants treated with T. velutinum and/or infected with R. solani. PMID:27540382

  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.

  1. Effect of carbon and nitrogen sources on growth and biological efficacy of Pseudomonas fluorescens and Bacillus subtilis against Rhizoctonia solani, the causal agent of bean damping-off.

    PubMed

    Peighamy-Ashnaei, S; Sharifi-Tehrani, A; Ahmadzadeh, M; Behboudi, K

    2007-01-01

    One of the most important environmental factors that regulate the growth and antagonistic efficacy of biocontrol agents is the medium. The aim of this paper was to find the nitrogen and carbon sources that provide maximum biomass production of strains P-5 and P-6 (Pseudomonas fluorescens), B-3 and B-16 (Bacillus subtilis) and minimum cost of media, whilst maintaining biocontrol efficacy. All of the strains were grown in seven liquid media (pH=6.9) including: sucrose + yeast extract, molasses of sugar beet + yeast extract in 2:1 and 1:1 w/w ratios, molasses of sugar beet + urea, nutrient broth, molasses and malt extract, at an initial inoculation of 1 x 10(5) CFU ml(-1). Cells from over night cultures used to inoculate soil at 1 x 10(9) CFU cm(-3) soil. At the same time, fungal inoculum (infected millet seed with Rhizoctonia solani) was added to soil at the rate of 2 g kg(-1) soil. Results indicated that growth of P-6, B-3 and B-16 in molasses + yeast extract (1:1 w/w) medium was significantly higher than in the other media. Molasses + yeast extract (1:1 and 2:1 w/w) media supported rapid growth and high cell yields in P-5. In greenhouse condition, results indicated that the influence of the media on the biocontrol efficacy of P-5, P-6, B-3 and B-16 was the same and Pseudomonas fluorescens P-5 in molasses and malt extract media reduced the severity of disease up to 72.8 percent. On the other hand, there were observed significant differences on bean growth after one month in greenhouse. P-5 in molasses + yeast extract (1:1 w/w) medium had the most effects on bean growth promotion. In this study molasses media showed good yield efficacy in all of the strains. The high sucrose concentration in molasses justifies the high biomass in all of the strains. Also, the low cost of molasses allows its concentration to be increased in media. On the other hand, yeast extract was the best organic nitrogen source for antagonist bacteria but it is expensive for an industrial process

  2. 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

  3. Improved genome sequence of the phytopathogenic fungus Rhizoctonia solani AG1-IB 7/3/14 as established by deep mate-pair sequencing on the MiSeq (Illumina) system.

    PubMed

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

    2015-06-10

    The phytopathogenic fungus Rhizoctonia solani AG1-IB of the phylum Basidiomycota affects various economically important crops comprising bean, rice, soybean, figs, cabbage and lettuce. The R. solani isolate 7/3/14 of the anastomosis group AG1-IB was deeply resequenced on the Illumina MiSeq system applying the mate-pair mode to improve its genome sequence. Assembly of obtained sequence reads significantly reduced the amount of scaffolds and improved the genome sequence of the isolate compared to the previous sequencing approach. The genome sequence of the AG1-IB isolate 7/3/14 now provides an up-graded basis to analyze genome features predicted to play a role in pathogenesis and for the development of strategies to antagonize the pathogenic impact of this fungus.

  4. 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 μCT) 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

  5. 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 μCT) 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.

  6. Establishment and interpretation of the genome sequence of the phytopathogenic fungus Rhizoctonia solani AG1-IB isolate 7/3/14.

    PubMed

    Wibberg, Daniel; Jelonek, Lukas; Rupp, Oliver; Hennig, Magdalena; Eikmeyer, Felix; Goesmann, Alexander; Hartmann, Anton; Borriss, Rainer; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas

    2013-08-20

    Anastomosis group AG1-IB isolates of the anamorphic basidiomycetous fungus Rhizoctonia solani Kühn affect various agricultural and horticultural important crops including bean, rice, soybean, figs, hortensia, cabbage and lettuce. To gain insights into the genome structure and content, the first draft genome sequence of R. solani AG1-IB isolate 7/3/14 was established. Four complete runs on the Genome Sequencer (GS) FLX platform (Roche Applied Science) yielding approx. a 25-fold coverage of the R. solani genome were accomplished. Assembly of the sequence reads by means of the gsAssembler software version 2.6 applying the heterozygotic mode resulted in numerous contigs and scaffolds and a predicted size of 87.1 Mb for the diploid status of the genome. 'Contig-length vs. read-count' analysis revealed that the assembled contigs can be classified into five different groups. Detailed BLAST-analysis revealed that most contigs of group II feature high-scoring matches to other contigs of the same group suggesting that distinguishable allelic variants exist for many genes. Due to the supposed diploid and heterokaryotic nature of R. solani AG1-IB 7/3/14, this result has been anticipated. However, the heterokaryotic character of the isolate is not really supported by sequencing data obtained for the isolate R. solani AG1-IB 7/3/14. Coverage of group III contigs is twice as high as for group II contigs which can also be explained by the diploid status of the genome and indistinguishable alleles on homologous chromosomes. Assembly of sequence data led to the identification of the rRNA unit (group V contigs) and the mitochondrial (mt) genome (group IV contigs) which is a circular molecule of 162,751 bp in size featuring a GC-content of 36.4%. The R. solani 7/3/14 mt-genome is one of the largest fungal mitochondrial genomes known to date. Its large size essentially is due to the presence of numerous non-conserved hypothetical ORFs and introns. Gene prediction for the R. solani AG1

  7. Strain-specific SCAR markers for the detection of Trichoderma harzianum AS12-2, a biological control agent against Rhizoctonia solani, the causal agent of rice sheath blight.

    PubMed

    Naeimi, S; Kocsubé, S; Antal, Zsuzsanna; Okhovvat, S M; Javan-Nikkhah, M; Vágvölgyi, C; Kredics, L

    2011-03-01

    In order to identify a specific marker for T. harzianum AS12-2, a strain capable of controlling rice sheath blight caused by Rhizoctonia solani, UP-PCR was performed using five universal primers (UP) both separately and in pairwise combinations. The application of two UP primers resulted in the amplification of unique fragments from the genomic DNA of T. harzianum AS12-2, clearly distinguishing it from other Trichoderma strains. The unique fragments had no significant sequence homology with any other known sequence available in databases. Based on the sequences of the unique fragments, 14 oligonucleotide primers were designed. Two primer sets amplified a fragment of expected size from the DNA of strain T. harzianum AS12-2 but not from any other examined strains belonging to T. harzianum, to other Trichoderma species assayed, or to other common fungi present in paddy fields of Mazandaran province, Iran. In conclusion, SCAR (sequence characterized amplified regions) markers were successfully identified and rapid, reliable tools were provided for the detection of an effective biocontrol Trichoderma strain, which can facilitate studies of its population dynamics and establishment after release into the natural environment.

  8. Reducing the Use of Pesticides with Site-Specific Application: The Chemical Control of Rhizoctonia solani as a Case of Study for the Management of Soil-Borne Diseases

    PubMed Central

    Le Cointe, Ronan; Simon, Thomas E.; Delarue, Patrick; Hervé, Maxime; Leclerc, Melen; Poggi, Sylvain

    2016-01-01

    Reducing our reliance on pesticides is an essential step towards the sustainability of agricultural production. One approach involves the rational use of pesticides combined with innovative crop management. Most control strategies currently focus on the temporal aspect of epidemics, e.g. determining the optimal date for spraying, regardless of the spatial mechanics and ecology of disease spread. Designing innovative pest management strategies incorporating the spatial aspect of epidemics involves thorough knowledge on how disease control affects the life-history traits of the pathogen. In this study, using Rhizoctonia solani/Raphanus sativus as an example of a soil-borne pathosystem, we investigated the effects of a chemical control currently used by growers, Monceren® L, on key epidemiological components (saprotrophic spread and infectivity). We tested the potential “shield effect” of Monceren® L on pathogenic spread in a site-specific application context, i.e. the efficiency of this chemical to contain the spread of the fungus from an infected host when application is spatially localized, in our case, a strip placed between the infected host and a recipient bait. Our results showed that Monceren® L mainly inhibits the saprotrophic spread of the fungus in soil and may prevent the fungus from reaching its host plant. However, perhaps surprisingly we did not detect any significant effect of the fungicide on the pathogen infectivity. Finally, highly localized application of the fungicide—a narrow strip of soil (12.5 mm wide) sprayed with Monceren® L—significantly decreased local transmission of the pathogen, suggesting lowered risk of occurrence of invasive epidemics. Our results highlight that detailed knowledge on epidemiological processes could contribute to the design of innovative management strategies based on precision agriculture tools to improve the efficacy of disease control and reduce pesticide use. PMID:27668731

  9. 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

    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.

  10. Extraction and identification of bioactive compounds (eicosane and dibutyl phthalate) produced by Streptomyces strain KX852460 for the biological control of Rhizoctonia solani AG-3 strain KX852461 to control target spot disease in tobacco leaf.

    PubMed

    Ahsan, Taswar; Chen, Jianguang; Zhao, Xiuxiang; Irfan, Muhammad; Wu, Yuanhua

    2017-12-01

    Streptomyces strain KX852460 having antifungal activity against Rhizoctonia solani AG-3 KX852461 that is the causal agent of target spot disease in tobacco leaf. The aim of the study was to determine the antifungal activity of Streptomyces strain KX852460 extract against R. solani AG-3 and to identify bioactive antifungal compounds produced by strain KX852460. Crude substance was produced by submerged fermentation process from Streptomyces strain KX852460. Various solvent was used to extract the culture filtrate. Among all, ethyl acetate extracted supernatant showed great potency against R. solani AG-3 KX852461. The active fractions were purified by silica gel column chromatography having 52 mm zone of inhibition against R. solani AG-3 KX852461. The purified fractions were identified by gas chromatography-mass spectrometry technique. Twenty-seven compounds were identified and most of the compounds were the derivatives of aromatic compounds. Eicosane (C20H42) and dibutyl phthalate (C16H22O4) were found antifungal compounds in this study. While morphinan, 7,8-didehydro-4,5-epoxy-17-methyl-3,6-bis[(trimethylsilyl)oxy]-, (5.Alpha. 6.Alpha)-(C23H35NO3Si2), cyclononasiloxane, octadecamethyl-(C18H54O9Si9) and benzoic acid, 2,5-bis(trimethylsiloxy) (C16H30O4Si3) were the major compounds with highest peak number. These results suggested that Streptomyces strain KX852460 had good general antifungal activity and might have potential biocontrol antagonist against R. solani AG-3 KX852461 to cure the target spot in tobacco leaf.

  11. The Wheat Ethylene Response Factor Transcription Factor PATHOGEN-INDUCED ERF1 Mediates Host Responses to Both the Necrotrophic Pathogen Rhizoctonia cerealis and Freezing Stresses1[C][W][OPEN

    PubMed Central

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

    2014-01-01

    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

  12. Pea Disease Diagnostic Series- Rhizoctonia seed, seedling and root rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pea disease diagnostic cards that growers can carry with them into the field that are water resistant and durable which can be used to identify the signs and symptoms of major pea pathogens were developed. Color photographs of major fungal, bacterial, and viral pathogens on peas and a brief descript...

  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. Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot of wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tissues of plants in the family Brassicaceae contain glucosinolates, compounds whose hydrolysis results in the release of various bioactive products including isothiocyanates. The broad spectrum of biological activity of these glucosinolate hydrolysis products has led to the promotion of brassicace...

  15. Effect of arbuscular mycorrhizal fungi on onion growth and onion stunting caused by Rhizoctonia solani, 2013.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A preliminary study was conducted in a greenhouse (15 ± 1oC, with supplemental lights for 12 h/day) to determine the role of AMF on onion growth and for reducing the severity of onion stunting, using a commercial AMF inoculant, BioTerra Plus, that contains 104 propagules/g (ppg) of Glomus intraradic...

  16. The pathogen biology, identification and management of Rhizoctonia species with emphasis on isolates infecting turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    R. solani is an economically important soilborne basidiomycetous pathogen of worldwide distribution and it is known to attack at least 188 species of higher plants, including crops, vegetables, ornamentals, forest trees and turfgrasses. The pathogenic isolates may belong to multiple genera and speci...

  17. Bacillus amyloliquefaciens SB14 from rhizosphere alleviates Rhizoctonia damping-off disease on sugar beet.

    PubMed

    Karimi, Elham; Safaie, Naser; Shams-Baksh, Masoud; Mahmoudi, Bagher

    2016-11-01

    The use of biocontrol strains recently has become a popular alternative to conventional chemical treatments. A set of bacteria isolated from sugar beet rhizosphere and from roots and shoots of apple and walnut were evaluated for their potential to control sugar beet seedling damping-off caused by R. solani AG-4 and AG2-2.The results of in vitro assays concluded that three isolates, SB6, SB14, SB15, obtained from rhizosphere of sugar beet and five isolates, AP2, AP4, AP6, AP7, AP8, obtained from shoots and roots of apple were the most effective antagonists that inhibited the mycelial growth of both R. solani isolates. Combination of several biochemical tests and partial sequencing of 16S rRNA and gyrBgenes revealed that eight efficient bacterial isolates could be assigned to the genus Bacillus and all could tolerate high temperatures and salt concentrations in their vegetative growth. The potential biocontrol activity of the eight bacterial antagonists were tested in greenhouse condition. The results indicated that four strains,B. amyloliquefaciens SB14, B. pumilus SB6,B. siamensis AP2 and B. siamensisAP8 exerted a significant influence on controlling of seedling damping-off and performed significantly better than others.However, the treatment of the seeds with bacteria was most effective when the isolate SB14 was used, which significantly controlled damping-off disease by 58% caused by R. solani AG-4 and by 52.5% caused by R. solani AG-2-2. This indicates that the use of beneficial bacterial native to the host plant may increase the success rate in screening biocontrols, because these microbes are likely to be better adapted to their host and its associated environmental conditions than are strains isolated from other plant species grown in different environmental conditions. We can infer from the results reported here that sugar beet plantsmay recruitbeneficial microbes to the rhizosphere to help them solve context-specific challenges.

  18. Identification of unknown sterile fungi as Rhizoctonia zeae and potential for biological control for fungal root diseases of sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several soilborne diseases routinely damage sugar beet in production areas of the Central High Plains, and it is becoming more common to find fields infested simultaneously with multiple pathogens. Due to a shortage of available fungicides for effective management of multiple diseases, alternative ...

  19. Evaluation of Rhizoctonia zeae as a potential biological control option for fungal root diseases of sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several common root diseases routinely damage sugar beet in Nebraska and other production areas of the Central High Plains, and it is becoming more common to find fields infested simultaneously with multiple pathogens. Due to the lack of available chemicals for economic management of soilborne dise...

  20. 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...

  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. In vitro evaluation of Pseudomonas bacterial isolates from rice phylloplane for biocontrol of Rhizoctonia solani and plant growth promoting traits.

    PubMed

    Akter, Shamima; Kadir, Jugah; Juraimi, Abdul Shukor; Saud, Halimi Mohd

    2016-07-01

    The ability for biocontrol and plant growth promotion of three Pseudomonas bacterial isolates namely Pseudomonas fluorescens (UMB20), Pseudomonas aeruginosa (KMB25) and Pseudomonas asplenii (BMB42) obtained from rice plants was investigated. Fungal growth inhibition by the isolates ranged from 86.85 to 93.15% in volatile and 100% in diffusible metabolites test. Among the isolates, BMB42 showed fungal growth inhibition significantly in the volatile metabolite test. Isolates UMB20 and BMB42 were able to synthesis chitinase with chitinolytic indices of 13.66 and 13.50, respectively. In case of -1,3-glucanase, all the isolates showed activity to produce this enzyme at varied levels and isolate KMB25 showed significantly highest activity (53.53 ppm). Among the three isolates, KMB25 showed positive response to protease production and all of them were negative to pectinase and lipase and positive to the production of siderophore, and HCN, and were able to solubilize tricalcium phosphate. All the three bacterial isolates were capable of forming biofilm at different levels. Above results suggest that phylloplane Pseudomonas bacterial isolates have potential for antifungal activities and plant growth promotion.

  3. Impacts of biocontrol products on Rhizoctonia disease of potato and soil microbial communities, and their persistence in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four commercial biocontrol formulations (Bacillus subtilis GB03, Burkholderia ambifaria type Wisconsin isolate J82, Trichoderma virens Gl-21, and Trichoderma harzianum strain T-22), a chemical seed treatment (Topsin, mancozeb, and cymoxanil mixture, TMC), and a combination chemical/biological treatm...

  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

    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.

  5. First Report of Aerial Blight of Ruth’s Golden Aster (Pityopsis ruthii) caused by Rhizoctonia solani in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ruth's golden aster (Pityopsis ruthii) is an endangered, herbaceous perennial that occurs only at a few sites along small reaches of the Hiwassee and Ocoee rivers in Polk County, Tennessee. This species has ornamental potential. In 2012, we vegetatively propagated various genotypes and established p...

  6. 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

  7. Stunted patches in onion bulb crops in Oregon and Washington: Etiology and yield loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onion stunting caused by Rhizoctonia spp. is an important soilborne disease in the Columbia Basin of Oregon and Washington. From 2010 to 2013, 251 isolates of Rhizoctonia or Rhizoctonia-like spp. were obtained from soil and onion plant samples collected from Oregon and Washington. Sequence analysis ...

  8. 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...

  9. 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.

  10. Seedling disease in Michigan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar beet seedlings (24 entries of a larger genetic population constructed to dissect Rhizoctonia disease reaction in sugar beet) were screened for their response to a highly virulent isolate of Rhizoctonia solani AG 2-2. Seedlings were grown to the two-leaf stage in the greenhouse, thinned to 15 p...

  11. Isolation of endosymbionts from Ipomoea carnea and Swainsona canescens that produce swainsonine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungi including Metarhizium anisopliae (Clavicipitaceae), Rhizoctonia leguminicola (Ceratobasidiaceae), and Undifilum (Pleosporaceae), an endophyte found in the plant genera Astragalus and Oxytropis (Fabaceae) have been reported to be responsible for the production of swainsonine. Based upon the ass...

  12. 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...

  13. Biological control of soilborne diseases in organic potato production as affected by varying environmental conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soilborne diseases are persistent problems in potato production and alternative management practices are needed, particularly in organic production, where control options are limited. Selected biocontrol organisms, including two naturally-occurring hypovirulent strains of Rhizoctonia solani (Rhs1a1 ...

  14. Synthesis, Characterization, and Antifungal Studies of Cr(III) Complex of Norfloxacin and Bipiridyl Ligand

    PubMed Central

    Debnath, Anamika; Hussain, Firasat; Masram, Dhanraj T.

    2014-01-01

    A novel slightly distorted octahedral complex of Cr(III) of norfloxacin (Nor) with the formula [CrIII(Nor)(Bipy)Cl2]Cl·2CH3OH has been synthesized hydrothermally in the presence of a N-containing heterocyclic compound 2,2′-bipyridyl (Bipy). The complex was characterized with FT-IR, elemental analysis, UV-visible spectroscopy, and X-ray crystallography. Spectral studies suggest that the Nor acts as a deprotonated bidentate ligand. Thermal studies were also carried out. The synthesised complex was screened against four fungi Pythium aphanidermatum (PA), Sclerotinia rolfsii (SR), Rhizoctonia solani (RS), and Rhizoctonia bataticola (RB). PMID:25276111

  15. 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...

  16. Cutting propagation of azaleas using hot water treatments to control pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight, caused by certain binucleate species of Rhizoctonia, occurs yearly on some azalea cultivars during nursery production in the southern and eastern U.S. Azalea shoots collected for cutting propagation can harbor the pathogen, thus allowing the disease to be perpetuated during the cu...

  17. Pre-breeding for root rot resistance using root morphology and shoot length.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our goal is to identify new wheat varieties that display field resistance/tolerance to root rot diseases, such as those caused by Rhizoctonia and Pythium. We are tapping into the genetic diversity of ‘synthetic’ hexaploid wheats (genome composition AABBDD), which were generated at CIMMYT by artifici...

  18. Antifungal, Mosquito Deterrent, and Larvicidal Activity of N-(benzylidene)-3-cyclohexylpropionic Acid Hydrazide Derivatives

    DTIC Science & Technology

    2013-01-01

    Alternaria alternata, Botrytis cinerea , Rhizoctonia solani, Fusarium culmorum, Phytohtora cactorum, and Erysiphe graminis. More recently, the research...the untreated positive growth controls were used to evaluate fungal growth . The SAS, Proc ANOVA (Statistical Anal- ysis System, Cary, North Carolina...were evaluated for their anti- fungal activity against Colletotrichum, Botrytis , Fusarium, and Phomopsis species and for their biting deterrent and

  19. 77 FR 18806 - Fluxapyroxad; Receipt of Application for Emergency Exemption for Use on Rice in Louisiana...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... AGENCY Fluxapyroxad; Receipt of Application for Emergency Exemption for Use on Rice in Louisiana... pesticide fluxapyroxad (CAS No. 907204-31-3) to treat up to 40,000 acres of rice to control sheath blight... fluxapyroxad on rice to control sheath blight caused by the fungus Rhizoctonia solani. Information...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. Genome sequence of the plant growth-promoting rhizobacterium Bacillus sp. strain 916.

    PubMed

    Wang, Xiaoyu; Luo, Chuping; Chen, Zhiyi

    2012-10-01

    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.

  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. 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...

  8. 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...

  9. Disease evaluations and agronomic traits of advanced peanut breeding lines in 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 21 peanut cultivars and high-oleic advanced breeding lines were evaluated in small field plots in 2013 for agronomic traits (crop value, yield, seed grade, and characteristics) and resistance to diseases (Sclerotinia blight, southern blight, and Pythium and Rhizoctonia pod rot). Among th...

  10. Sugar beet activities of the USDA-ARS East Lansing conducted in cooperation with Saginaw Research & Extension Center during 2013 (including Project 905)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation and rating plots were planted at the Saginaw Valley Research & Extension Center (SVREC) in Frankenmuth, MI in 2013 that focused on Cercospora leaf spot and Rhizoctonia seedling disease performance of a wide range of Beta vulgaris materials. Leaf spot trials were conducted in conjunction w...

  11. Sugar beet activities of the USDA-ARS East Lansing conducted in cooperation with Saginaw Research & Extension Center during 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation and rating plots were planted at the Saginaw Valley Research & Extension Center (SVREC) in Frankenmuth, MI in 2014 that focused on Cercospora leaf spot (CLS) and Rhizoctonia crown and root rot (CRR) disease performance of a wide range of Beta vulgaris materials. CLS and CRR trials were co...

  12. Dealing with damping-off

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Damping-off is a common disease that rots and kills both seeds and recently germinated seedlings. The disease is caused by number of different soilborne pathogens, including true fungi (Botrytis, Fusarium, and Rhizoctonia species) and oomycetes (Phytophthora and Pythium species). The seedlings of mo...

  13. 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...

  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. Identification of external inoculum sources of apple replant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple replant disease (ARD) is an important disease world-wide and occurs when old apple orchards are replanted with apple. The disease is mainly caused by biological agents, since fumigation alleviates symptom development. The main ARD causative agents are fungi (Rhizoctonia solani AG-5 and AG-6, a...

  17. Pre-Breeding for root rot resistance using root morphology traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root rot caused by the fungal pathogen Rhizoctonia solani can be a major yield-limiting disease in minimal tillage or direct-seeded cereal production systems. Reduced tillage greatly influences the plant residue retained on the soil surfaces. This retained residue (green bridge) provides increased d...

  18. 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...

  19. 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)...

  20. 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...

  1. 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)...

  2. 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...

  3. 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 ...

  4. Project 722: Seedling diseases of sugar beet – diversity and host interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In five years of testing, Rhizoctonia solani and Fusarium spp. were commonly isolated from infected field-isolated diseased sugar beet seedlings. Which fungus is more commonly isolated from seedlings has varied over the seasons. For example, R. solani was the most frequently isolated pathogen in 201...

  5. Seedling diseases of sugar beet – diversity and host interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seedling diseases cause loss of plant stand due to pre- and post-emergence damping-off and weakened plants due to root or hypocotyl infection. Several pathogens cause seedling disease of sugar beet, including Rhizoctonia solani, Aphanomyces cochlioides, Pythium species, and Fusarium species. Differe...

  6. Jinggangmycin increases fecundity of the brown planthopper, Nilaparvata lugens (Stal), via fatty acid synthase gene expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 d...

  7. 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...

  8. 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...

  9. 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...

  10. 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),...

  11. 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...

  12. 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...

  13. Induced systemic resistance in Arabidopsis against Pseudomonas syringae pv. tomato by disease suppressive soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two-week-old Arabidopsis thaliana ecotype Col-0 seedlings were transferred into an autoclaved sand-soil mixture amended with 10% or 20% (weight/weight) soil that is suppressive to either take-all or Rhizoctonia root rot of wheat from fields in Washington State USA. These soils contain population siz...

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

    PubMed

    Těšitelová, Tamara; Kotilínek, Milan; Jersáková, Jana; Joly, François-Xavier; Košnar, Jiří; 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.

  15. Effect of neem (Azardirachta indica A. Juss) seeds and leaves extract on some plant pathogenic fungi.

    PubMed

    Moslem, M A; El-Kholie, E M

    2009-07-15

    In this study plant pathogenic fungi Alternaria solani, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum were chosen to study the effect of ethanolic, hexane and methanolic extracts of neem seeds and leaves. Antifungal effects of neem leave and seed extracts obtained by ethanol, hexane and ptrolium ether were examined separately in vitro against Fusarium oxysporum, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum. Results indicated that seeds and leaves extracts could cause growth inhibition of tested fungi, although the rate of inhibition of tested fungi varied with different extracts and concentrations. But all these extracts and concentrations of extract inhibited the growth of pathogenic fungi at a significant level. Azadirachtin, nimonol and expoxyazdirodione were detected from neem extract by using High Performance Liquid Chromatography (HPLC). We can conclude that neem leave and seed extracts were effective as antifungal against all tested fungi but F. oxysporum and R. solani were the most sensitive fungi.

  16. Agricultural Use of Burkholderia (Pseudomonas) Cepacia: A Threat to Human Health?

    DTIC Science & Technology

    1998-06-01

    Benson D. Pyrrolnitrin and phenazine production by Pseudomonas cepacia strain 5.5B, a biocontrol agent of Rhizoctonia solani. Appl Microbiol Biotechnol...INTERNET DOCUMENT INFORMATION FORM A. Report Title: Agricultural Use of Burkholderia ( Pseudomonas ) cepacia: A Threat to Human Health? B. DATE...questions, contact the above OCA Representative for resolution. rIfllC QUALITY INSPECTED 1 O-* Synopses Agricultural Use of Burkholderia ( Pseudomonas

  17. Effects of nematicides on cotton root mycobiota.

    PubMed

    Baird, R E; Carling, D E; Watson, C E; Scruggs, M L; Hightower, P

    2004-02-01

    Baseline information on the diversity and population densities of fungi collected from soil debris and cotton (Gossypium hirsutum L.) roots was determined. Samples were collected from Tifton, GA, and Starkville, MS containing cotton field soil treated with the nematicides 1,3-dichloroproprene (fumigant) and aldicarb (granules). A total of 10,550 and 13,450 fungal isolates were collected from these two study sites, respectively. Of this total, 34 genera of plant pathogenic or saprophytic species were identified. Pathogenic root fungi included Fusarium spp. (40% of all isolations), Macrophomina, Pythium, Rhizoctonia, and Sclerotium. Fusarium and Rhizoctonia were the most common fungal species identified and included F. oxysporum, F. verticillioides and F. solani, the three Fusarium species pathogenic on cotton plants. Population densities of Fusarium were not significantly different among locations or tissue types sampled. Macrophomina was isolated at greater numbers near the end of the growing seasons. Anastomosis groups of R. solani isolated from roots and soil debris included AG-3, -4, -7, 2-2, and -13 and anastomosis groups of binucleate Rhizoctonia included CAG-2, -3, and -5. Occurrences and frequency of isolations among sampling dates were not consistent. Fluctuations in the frequency of isolation of Rhizoctonia did not correspond with changes in frequency of isolation of the biological control fungus, Trichoderma. When individual or pooled frequencies of the mycobiota were compared to nematicide treatments, no specific trends occurred between treatments, application methods or rates. Results from this study show that use of 1,3-D and aldicarb in cotton fields does not significantly impact plant pathogenic fungi or saprophytic fungal populations. Thus cotton producers need not adjust seedling disease control measures when these two nematicides are used.

  18. 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

  19. 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

  20. A new steroidal saponin, yuccalan, from the leaves of Yucca smalliana.

    PubMed

    Jin, Yu-Lan; Kuk, Ju-Hee; Oh, Kyung-Taek; Kim, Young-Ju; Piao, Xiang-Lan; Park, Ro-Dong

    2007-05-01

    An extract of the leaves of Yucca smalliana Fern. (Agavaceae) showed potential antimicrobial activity. Employing a bioassay linked fractionation method, one of the active principles, namely yuccalan, was isolated as a new steroidal saponin. The structure of the new steroidal saponin was elucidated as 3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(3beta, 5alpha, 6alpha, 25S)-spirostan-3,6,27-triol (1) using various spectroscopic techniques, including IR, MS, 1D and 2D 1H-NMR, and 13C-NMR. The purified yuccalan showed antifungal activities against both Rhizoctonia solani and Fusarium oxysporum.

  1. 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.

  2. 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.

  3. Phytophthora tropicalis on Hedera helix and Epipremnum aureum in Polish greenhouses.

    PubMed

    Orlikowski, L B; Trzewik, A; Wiejacha, K

    2006-01-01

    Phytophthora tropicalis was isolated from Hedera helix and Epipremnum aureum showing discoloration of leaves, necrosis of shoot base, spread upwards and on roots. The species was detected from 7/8 plants of Hedera and 3/4 of Epipremnum. Additionally Botrytis cinerea, Fusarium avenaceum and Rhizoctonia solani were recovered from some of diseased plants. P. tropicalis caused leaf necrosis of 13 plant species and tomato seedlings. The quickest spread of necrosis was observed on leaves of Peperomia magnoliaefolia, Pelargonium zonale and Phalaenopsis x hybridum. The disease developed at temperature ranged from 10 degrees to 32.5 degrees C with optimum 30 degrees C.

  4. Opportunistic invasive fungal pathogen Macrophomina phaseolina prognosis from immunocompromised humans to potential mitogenic RBL with an exceptional and novel antitumor and cytotoxic effect.

    PubMed

    Arora, P; Dilbaghi, N; Chaudhury, A

    2012-02-01

    With the ever-increasing risk for fungal infections, one can no longer ignore fungi. It is imperative that clinical manifestations "presume fungus" with their epidemiologic and pathogenic features when evaluating a potentially infected patient. In the high-risk patient groups, fungi with intrinsic resistance to antifungal agents already exist, with a tendency to emerge as opportunistic pathogens. One of the smart pathogens is Macrophomina phaseolina, with the potential to disarm plant, animal, and human immunity. The response prophylaxis may vary from antifungal therapy and surgical measures to biochemical (Rhizoctonia bataticola lectin [RBL] with antitumor and cytotoxic nature) and gene therapeutics.

  5. Symbiotic seed germination and protocorm development of Aa achalensis Schltr., a terrestrial orchid endemic from Argentina.

    PubMed

    Sebastián, Fracchia; Vanesa, Silvani; Eduardo, Flachsland; Graciela, Terada; Silvana, Sede

    2014-01-01

    Aa achalensis is an endangered terrestrial orchid endemic from Argentina. In vitro symbiotic seed germination was evaluated for its propagation. Five different fungal strains were isolated from this species: two Rhizoctonia-like related to Thanatephorus cucumeris and three ascomicetaceous fungi belonging to Phialophora graminicola and one to an uncultured Pezizaceae. All five isolates promoted seed germination being one T. cucumeris strain the most effective. After 16 weeks of growth, 30% of A. achalensis protocorms developed until seedlings with two/four leaves in this treatment. These findings open an opportunity to the knowledge and preservation of this species.

  6. Synthesis and bioactivities of Phenazine-1-carboxylic acid derivatives based on the modification of PCA carboxyl group.

    PubMed

    Xiong, Zhipeng; Niu, Junfan; Liu, Hao; Xu, Zhihong; Li, Junkai; Wu, Qinglai

    2017-03-08

    Phenazine-1-carboxylic acid (PCA) as a natural product widely exists in microbial metabolites of Pseudomonads and Streptomycetes and has been registered for the fungicide against rice sheath blight in China. To find higher fungicidal activities compounds and study the effects on fungicidal activities after changing the carboxyl group of PCA, we synthesized a series of PCA derivatives by modifying the carboxyl group of PCA and their structures were confirmed by (1)H NMR and HRMS. Most compounds exhibited significant fungicidal activities in vitro. In particular, compound 6 exhibited inhibition effect against Rhizoctonia solani with EC50 values of 4.35mg/L and compound 3b exhibited effect against Fusarium graminearum with EC50 values of 8.30mg/L, compared to the positive control PCA with its EC50 values of 7.88mg/L (Rhizoctonia solani) and 127.28mg/L (Fusarium graminearum), respectively. The results indicated that the carboxyl group of PCA could be modified to be amide group, acylhydrazine group, ester group, methyl, hydroxymethyl, chloromethyl and ether group etc. And appropriate modifications on carboxyl group of PCA were useful to extend the fungicidal scope.

  7. Mycorrhizal compatibility and symbiotic seed germination of orchids from the Coastal Range and Andes in south central Chile.

    PubMed

    Herrera, Hector; Valadares, Rafael; Contreras, Domingo; Bashan, Yoav; Arriagada, Cesar

    2017-04-01

    Little is known about Orchidaceae plants in Chile and their mycorrhizal associations, a key issue for designing protective actions for endangered species. We investigated root fungi from seven terrestrial orchid species to identify potential mycorrhizal fungi. The main characteristics of Rhizoctonia-like fungi were observed under light microscopy, and isolates were identified through PCR-ITS sequencing. Molecular identification of fungal sequences showed a high diversity of fungi colonizing roots. Fungal ability to germinate seeds of different orchids was determined in symbiotic germination tests; 24 fungal groups were isolated, belonging to the genera Tulasnella, Ceratobasidium, and Thanatephorus. Furthermore, dark septate and other endophytic fungi were identified. The high number of Rhizoctonia-like fungi obtained from adult orchids from the Coastal mountain range suggests that, after germination, these orchids may complement their nutritional demands through mycoheterotrophy. Nonetheless, beneficial associations with other endophytic fungi may also co-exist. In this study, isolated mycorrhizal fungi had the ability to induce seed germination at different efficiencies and with low specificity. Germin ation rates were low, but protocorms continued to develop for 60 days. A Tulasnella sp. isolated from Chloraea gavilu was most effective to induce seed germination of different species. The dark septate endophytic (DSE) fungi did not show any effect on seed development; however, their widespread occurrence in some orchids suggests a putative role in plant establishment.

  8. 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

  9. Suppression of Specific Apple Root Pathogens by Brassica napus Seed Meal Amendment Regardless of Glucosinolate Content.

    PubMed

    Mazzola, M; Granatstein, D M; Elfving, D C; Mullinix, K

    2001-07-01

    ABSTRACT The impact of Brassica napus seed meal on the microbial complex that incites apple replant disease was evaluated in greenhouse trials. Regardless of glucosinolate content, seed meal amendment at a rate of 0.1% (vol/vol) significantly enhanced growth of apple and suppressed apple root infection by Rhizoctonia spp. and Pratylenchus penetrans. High glucosinolate B. napus cv. Dwarf Essex seed meal amendments did not consistently suppress soil populations of Pythium spp. or apple root infection by this pathogen. Application of a low glucosinolate containing B. napus seed meal at a rate of 1.0% (vol/vol) resulted in a significant increase in recovery of Pythium spp. from apple roots, and a corresponding reduction in apple seedling root biomass. When applied at lower rates, B. napus seed meal amendments enhanced populations of fluorescent Pseudomonas spp., but these bacteria were not recovered from soils amended with seed meal at a rate of 2% (vol/vol). Seed meal amendments resulted in increased soil populations of total bacteria and actinomycetes. B. napus cv. Dwarf Essex seed meal amendments were phytotoxic to apple when applied at a rate of 2% (vol/vol), and phytotoxicity was not diminished when planting was delayed for as long as 12 weeks after application. These findings suggest that B. napus seed meal amendments can be a useful tool in the management of apple replant disease and, in the case of Rhizoctonia spp., that disease control operates through mechanisms other than production of glucosinolate hydrolysis products.

  10. 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.

  11. Fungi associated with the southern Eurasian orchid Spiranthes spiralis (L.) Chevall.

    PubMed

    Tondello, Alessandra; Vendramin, Elena; Villani, Mariacristina; Baldan, Barbara; Squartini, Andrea

    2012-04-01

    The hitherto unknown relationships between the European orchid Spiranthes spiralis (L.) Chevall and its internally associated fungi were explored by a combined approach involving microscopy-based investigations at a morpho-histological level as well as by molecular analyses of the identity of the eukaryotic endophytes present in the root tissue of the plant. We found that this orchid which is currently reported to have a vulnerable status in northern Italy, can host and interact with at least nine types of fungi. Some of these fungi show similarity to mycorrhizal genera found in orchids such as the Ceratobasidium-Rhizoctonia group. Other fungi found are from the genera Davidiella (Ascomycota), Leptosphaeria (Ascomycota), Alternaria (Ascomycota), and Malassezia (Basidiomycota), some of which until have not previously been reported to have an endophytic relationship with plants. The repeated occurrence of often pathogenic fungi such as Fusarium oxysporum, Bionectria ochroleuca, and Alternaria sp., within healthy specimens of this orchid suggests a tempered interaction with species that are sometimes deleterious to non-orchid plants. The fact is reminiscent of the symbiotic compromise established by orchids with fungi of the rhizoctonia group.

  12. Purification and characterization of a novel antifungal protein from Bacillus subtilis strain B29*

    PubMed Central

    Li, Jing; Yang, Qian; Zhao, Li-hua; Zhang, Shu-mei; Wang, Yu-xia; Zhao, Xiao-yu

    2009-01-01

    An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel® P-100. The protein was absorbed on DEAE-cellulose and Bio-Gel® P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pI value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited inhibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia sclerotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B29I also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germinated spores. PMID:19353744

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

    PubMed

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

    2015-05-01

    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.

  14. An antifungal compound involved in symbiotic germination of Cypripedium macranthos var. rebunense (Orchidaceae).

    PubMed

    Shimura, Hanako; Matsuura, Mayumi; Takada, Noboru; Koda, Yasunori

    2007-05-01

    Germination of orchid seeds fully depends on a symbiotic association with soil-borne fungi, usually Rhizoctonia spp. In contrast to the peaceful symbiotic associations between many other terrestrial plants and mycorrhizal fungi, this association is a life-and-death struggle. The fungi always try to invade the cytoplasm of orchid cells to obtain nutritional compounds. On the other hand, the orchid cells restrict the growth of the infecting hyphae and obtain nutrition by digesting them. It is likely that antifungal compounds are involved in the restriction of fungal growth. Two antifungal compounds, lusianthrin and chrysin, were isolated from the seedlings of Cypripedium macranthos var. rebunense that had developed shoots. The former had a slightly stronger antifungal activity than the latter, and the antifungal spectra of these compounds were relatively specific to the nonpathogenic Rhizoctonia spp. The level of lusianthrin, which was very low in aseptic protocorm-like bodies, dramatically increased following infection with the symbiotic fungus. In contrast, chrysin was not detected in infected protocorm-like bodies. These results suggest that orchid plants equip multiple antifungal compounds and use them at specific developmental stages; lusianthrin maintains the perilous symbiotic association for germination and chrysin helps to protect adult plants.

  15. 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.

  16. A New Operation for Producing Disease-Suppressive Compost from Grass Clippings

    PubMed Central

    Nakasaki, Kiyohiko; Hiraoka, Sachiko; Nagata, Hiroyuki

    1998-01-01

    This study evaluated the use of grass clippings discharged from golf courses as the raw material for production of a suppressive compost to control Rhizoctonia large-patch disease in mascarene grass. Bacillus subtilis N4, a mesophilic bacterium with suppressive effects on the pathogenic fungus Rhizoctonia solani AG2-2, was used as an inoculum in a procedure developed with the aim of controlling composting temperatures and inoculation timing. The population density of mesophilic bacteria in the raw material was reduced to around 5 log10 CFU/g (dry weight) of composting material in the self-heating reaction at the initial stage of composting by maintaining a temperature of 80°C for 1 day. The inoculum was applied immediately, and the composting material was maintained at 40°C for 3 days. This served both to highly concentrate the suppressive bacterium and to achieve sporulation. The temperature was then raised to 60°C and maintained, enabling hygienic, high-speed composting while maintaining the population density of the suppressive bacterium as high as 8 log10 CFU/g (dry weight) in the compost. The suppressiveness of compost made in this way was confirmed in a turf grass disease prevention assay. PMID:9758834

  17. Omics for understanding synergistic action of validamycin A and Trichoderma asperellum GDFS1009 against maize sheath blight pathogen

    PubMed Central

    Wu, Qiong; Zhang, Lida; Xia, Hai; Yu, Chuanjin; Dou, Kai; Li, Yaqian; Chen, Jie

    2017-01-01

    Sheath blight, causes by Rhizoctonia spp., threaten maize yield every year throughout the world. Trichoderma could degrade Rhizoctonia solani on maize mainly via competition and hyperparasitism, whereas validamycin A could efficiently inhibit the growth of R. solani via disturbing the energy system. By contrast, validamycin A is efficient but it takes effect in a short period, while Trichoderma takes effect in a long period though time-consuming. To overcome the disadvantages, Trichoderma asperellum GDFS1009 was used together with validamycin A. In vitro tests proved that the combined pathogen-inhibiting efficiency was significantly improved. Furthermore, results based on transcriptome and metabolome showed that validamycin A had no significant effects on growth, basic metabolism and main bio-control mechanisms of T. asperellum GDFS1009. Such few impacts may be attributed to detoxification and tolerance mechanism of T. asperellum GDFS1009. In addition, T. asperellum GDFS1009 has an ability to relieve the stress caused by validaymicn A. Meanwhile, liquid chromatography-mass spectrometry (LC-MS) results showed that only minor degradation (20%) of validamycin A was caused by T. asperellum GDFS1009 during cofermentation. All results together provide solid bases for validamycin A synergy with T. asperellum GDFS1009 in their combined biocontrol application. PMID:28057927

  18. Role of phenazines and cyclic lipopeptides produced by pseudomonas sp. CMR12a in induced systemic resistance on rice and bean.

    PubMed

    Ma, Zongwang; Hua, Gia Khuong Hoang; Ongena, Marc; Höfte, Monica

    2016-08-25

    Pseudomonas sp. CMR12a produces two different classes of cyclic lipopeptides (CLPs) (orfamides and sessilins), which all play a role in direct antagonism against soilborne pathogens. Here we show that Pseudomonas sp. CMR12a is also able to induce systemic resistance to Magnaporthe oryzae on rice and to the web blight pathogen Rhizoctonia solani AG2-2 on bean. Plant assays with biosynthesis mutants of Pseudomonas sp. CMR12a impaired in the production of phenazines and/or CLPs and purified metabolites revealed that distinct bacterial determinants are responsible for inducing systemic resistance in these two pathosystems. In rice, mutants impaired in phenazine production completely lost their ability to induce systemic resistance, while a soil drench with pure phenazine-1-carboxamide (PCN) at a concentration of 0.1 or 1 μM was active in inducing resistance against M. oryzae. In bean, mutants that only produced phenazines, sessilins or orfamides were still able to induce systemic resistance against Rhizoctonia web blight, but a balanced production of these metabolites was needed. This study not only shows that Pseudomonas sp. CMR12a can protect rice to blast disease and bean to web blight disease, but also displays that the determinants involved in induced systemic resistance are plant, pathogen and concentration dependent.

  19. Comparison of Pratylenchus penetrans Infection and Maladera castanea Feeding on Strawberry Root Rot

    PubMed Central

    LaMondia, J. A.; Cowles, R. S.

    2005-01-01

    The interaction of lesion nematodes, black root rot disease caused by Rhizoctonia fragariae, and root damage caused by feeding of the scarab larva, Maladera castanea, was determined in greenhouse studies. Averaged over all experiments after 12 weeks, root weight was reduced 13% by R. fragariae and 20% by M. castanea. The percentage of the root system affected by root rot was increased by inoculation with either R. fragariae (35% more disease) or P. penetrans (50% more disease) but was unaffected by M. castanea. Rhizoctonia fragariae was isolated from 9.2% of the root segments from plants not inoculated with R. fragariae. The percentage of R. fragariae-infected root segments was increased 3.6-fold by inoculation with R. fragariae on rye seeds. The presence of P. penetrans also increased R. fragariae root infection. The type of injury to root systems was important in determining whether roots were invaded by R. fragariae and increased the severity of black root rot. Pratylenchus penetrans increased R. fragariae infection and the severity of black root rot. Traumatic cutting action by Asiatic garden beetle did not increase root infection or root disease by R. fragariae. Both insects and diseases need to be managed to extend the productive life of perennial strawberry plantings. PMID:19262852

  20. Molecular Characterisation of Endophytic Fungi from Roots of Wild Banana (Musa acuminata)

    PubMed Central

    Zakaria, Latiffah; Jamil, Muhamad Izham Muhamad; Anuar, Intan Sakinah Mohd

    2016-01-01

    Endophytic fungi inhabit apparently healthy plant tissues and are prevalent in terrestrial plants, especially root tissues, which harbour a wide assemblage of fungal endophytes. Therefore, this study focused on the isolation and characterisation of endophytic fungi from the roots of wild banana (Musa acuminata). A total of 31 isolates of endophytic fungi were isolated from 80 root fragments. The endophytic fungi were initially sorted according to morphological characteristics and identified using the sequences of the translation elongation factor-1α (TEF-1α) gene of Fusarium spp. and the Internal Transcribed Spacer (ITS) regions of other fungi. The most common fungal isolates were species of the genus Fusarium, which were identified as F. proliferatum, Fusarium sp., F. solani species complex, and F. oxysporum. Other isolated endophytic fungi included Curvularia lunata, Trichoderma atroviride, Calonectria gracilis, Rhizoctonia solani, Bionectria ochroleuca, and Stromatoneurospora phoenix (Xylariceae). Several of the fungal genera, such as Fusarium, Trichoderma, Rhizoctonia, and Xylariceae, are among the common fungal endophytes reported in plants. This study showed that the roots of wild banana harbour a diverse group of endophytic fungi. PMID:27019688

  1. 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

  2. Phytopathogenic fungal inhibitors from celery seeds.

    PubMed

    Liu, Tao; Liu, Fu-Guang; Xie, Hui-Qin; Mu, Qing

    2012-07-01

    Extract of celery (Apium graveolens L.) seeds was investigated against phytopathogenic fungi. The light petroleum extract showed promising inhibition activities in the tests against Rhizoctonia solani and Fusarium oxysporum f. sp. vasinfecum. Chromatographic separation of the extract gave 19 fractions, one of which, QCZ-4, possessed significant inhibitory rates of 64.6%, 88.4% and 54.7% at a concentration of 100 ppm against R. solani, F. oxysporium f. sp. vasinfecum and Alternaria alternata, respectively. Major components in the active fraction were identified by GC-MS as p-(2-aminoethyl)phenol (39.7%), 3-(3,4-dimethybenzoyl) propionic acid (32.6%) and p-heptylphenol (26.9%).

  3. Screening of Pseudomonas and Bacillus isolates for potential biocontrol of the damping-off of bean (Phaseolus coccineus).

    PubMed

    Peighami-Ashnaei, S; Sharifi-Tehrani, A; Ahmadzadeh, M; Behboudi, K

    2009-01-01

    In this study fifteen isolates of identified Pseudomonas fluorescens and Bacillus subtilis were investigated for control of bean damping-off disease caused by Rhizoctonia solani. In vitro, P. fluorescens P-6 and B. subtilis B-3 showed the most inhibitory zone in dual culture assay against R. solani. The growth of P-6 (4.5 x 10(8) cfu/ml) was significantly higher than in the other treatments. In greenhouse condition, all of the isolates effectively controlled damping-off on bean. P. fluorescens P-5 and P-6 showed the considerable results against R. solani and could reduce the damping-off disease from 100% to less than 30%. P-5, P-6 (P. fluorescens) and 8-16 (8. subtilis) strains had the highest effect on fresh weight of bean.

  4. 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.

  5. Isolation and identification of N-butyl-tetrahydro-5-oxofuran-2-carboxamide produced by Bacillus sp. L60 and its antifungal activity.

    PubMed

    Lee, Yong-Seong; Cho, Jeong-Yong; Moon, Jae-Hak; Kim, Kil-Yong

    2017-03-01

    Rhizoctonia solani is the cause of substantial economic loss in many crops. The aim of this study is to investigate biocontrol potential of Bacillus sp. L60 against R. solani and to purify an antifungal compound. In this study, Bacillus sp. L60 demonstrated significant antagonism toward R. solani with the dual culture assay. The antifungal compound was extracted from Bacillus sp. L60 culture supernatant with n-butanol, and identified as N-butyl-tetrahydro-5-oxofuran-2-carboxamide (BT-5O-2C) having molecular weights of 185.1052 Da with the formula C9 H15 NO3 using NMR and HR-ESI-MS analysis. The minimum inhibitory concentration (MIC) value of the antifungal compound was 256 µg ml(-1) against R. solani. Therefore, our results clearly demonstrated BT-5O-2C as well as Bacillus sp. L60 as potential biological control agents for the management of R. solani.

  6. Chemical composition and antifungal properties of essential oils of three Pistacia species.

    PubMed

    Duru, M E; Cakir, A; Kordali, S; Zengin, H; Harmandar, M; Izumi, S; Hirata, T

    2003-02-01

    The chemical composition of essential oils obtained from the leaves of Pistacia vera, Pistacia terebinthus, Pistacia lentiscus and the resin of Pistacia lentiscus were analyzed by GC and GC-MS. alpha-Pinene, beta-pinene, limonene, terpinen-4-ol and alpha-terpineol were found to be the major components. The antifungal activities of the above oils and P. lentiscus resin (total, acidic and neutral fractions) against the growth of three agricultural pathogens, Pythium ultimum, Rhizoctonia solani and Fusarium sambucinum were evaluated. Some doses of P. terebinthus, P. vera and P. lentiscus leaf oils and total and neutral fraction of P. lentiscus resin significantly inhibited the growth of R. solani. However, all samples did not show antifungal activity against P. ultimum and F. sambucinum, but increased the growth of F. sambucinum.

  7. Mycorrhizal status and diversity of fungal endophytes in roots of common buckwheat (Fagopyrum esculentum) and tartary buckwheat (F. tataricum).

    PubMed

    Likar, Matevz; Bukovnik, Urska; Kreft, Ivan; Chrungoo, Nikhil K; Regvar, Marjana

    2008-09-01

    To determine the mycorrhizal status and to identify the fungi colonising the roots of the plants, common buckwheat (Fagopyrum esculentum) and tartary buckwheat (F. tataricum) were inoculated with an indigenous fungal mixture from a buckwheat field. Root colonisation was characterised by the hyphae and distinct microsclerotia of dark septate endophytes, with occasional arbuscules and vesicles of arbuscular mycorrhizal fungi. Sequences of arbuscular mycorrhizal fungi colonising tartary buckwheat clustered close to the Glomus species group A. Sequences with similarity to the Ceratobasidium/Rhizoctonia complex, a putative dark septate endophyte fungus, were amplified from the roots of both common and tartary buckwheat. To the best of our knowledge, this is the first report of arbuscular mycorrhizal colonisation in tartary buckwheat and the first molecular characterisation of these fungi that can colonise both of these economically important plant species.

  8. Antifungal activity in seed coat extracts of woodland plants.

    PubMed

    Warr, Susan J; Thompson, Ken; Kent, Martin

    1992-11-01

    Aqueous extracts from seeds of four woodland ground flora species (Hyacinthoides non-scripta, Allium ursinum, Digitalis purpurea and Hypericum pulchrum) were tested for antifungal activity using a petriplate technique. Four species of fungi were investigated. The growth of three of these (Trichoderma viride, Rhizoctonia solani and Pythium sp.) was not affected by any of the seed coat extracts. The growth of Botrytis cinerea was inhibited by the seed coat extracts of Digitalis purpurea and Hypericum pulchrum but not by those of Hyacinthoides non-scripta or Allium ursinum. The buried seeds of Digitalis purpurea and Hypericum pulchrum can survive in woodland soils for long periods, whereas those of Hyacinthoides non-scripta and Allium ursinum are short-lived. The presence of antifungal agents in the seed coats of persistent species and their possible role in protecting seeds against fungal pathogens is discussed.

  9. 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.

  10. Antibacterial and antifungal activities of Otanthus maritimus (L.) Hoffmanns. & Link essential oil from Sicily.

    PubMed

    Basile, Adriana; Rigano, Daniela; Sorbo, Sergio; Conte, Barbara; Rosselli, Sergio; Bruno, Maurizio; Senatore, Felice

    2013-01-01

    The chemical composition of the essential oil obtained from the flowers of Otanthus maritimus L., a perennial plant growing wild in maritime sands in the Mediterranean region, was investigated by GC and GC-MS analyses. Totally 66 were identified. The oil was dominated by the high content of monoterpene compounds, especially oxygenated monoterpenes which accounted for 73.1%. The most abundant components were yomogi alcohol (20.8%), camphor (15.8%), artemisyl acetate (15.3%) and artemisia alcohol (13.7%). The oil was tested against two Gram (+) and six Gram (-) bacterial strains, both American Type Culture Collection standard strains and clinically isolated (CI), one potentially pathogenic yeast (Candida albicans CI) and two filamentous phytopathogenic fungi (Botrytis cinerea and Rhizoctonia solani). The results show that the oil from O. maritimus exerts strong antibacterial and antifungal activities.

  11. 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

  12. Novel macrocyclic molecules based on 12a-N substituted 16-membered azalides and azalactams as potential antifungal agents.

    PubMed

    Wang, Xiaolei; Zhang, Shun; Pang, Yanlong; Yuan, Huihui; Liang, Xiaomei; Zhang, Jianjun; Wang, Daoquan; Wang, Mingan; Dong, Yanhong

    2014-02-12

    Novel macrocyclic molecules comprising sulfonyl and acyl moiety at the position N-12a of 16-membered azalides (6a-n) and azalactams (10a-r) scaffold were synthesized from cyclododecanone 1 as starting material via 5 steps and 4 steps, respectively. The antifungal activity of these compounds against Sclerotinia sclerotiorum, Pyricularia oryzae, Botrytis cinerea, Rhizoctonia solani and Phytophthora capsici were evaluated and found that compounds possessing α-exomethylene (6c, 6d, 6e and 6g) showed antifungal activity comparable to commercial fungicide Chlorothalonil against P. oryzae and compounds possessing p-chlorobenzoyl exhibited enhanced antifungal activity than those with other substituents against S. sclerotiorum, P. oryzae, and B. cinerea. These findings suggested that the α-exomethylene and p-chlorobenzoyl may be two potential pharmacological active groups with antifungal activities.

  13. Optimization for rapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi

    NASA Astrophysics Data System (ADS)

    Krishnaraj, C.; Ramachandran, R.; Mohan, K.; Kalaichelvan, P. T.

    In this present study, silver nanoparticles were synthesized by green chemistry approach using Acalypha indica leaf extract as reducing agents. The reaction medium employed in the synthesis process was optimized to attain better yield, controlled size and stability. Further, the biosynthesized silver nanoparticles were conformed through UV-vis spectrum, XRD and HR-TEM analyses. Different concentration of silver nanoparticles were tested to know the inhibitory effect of fungal plant pathogens namely Alternaria alternata, Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, Botrytis cinerea and Curvularia lunata. Interestingly, 15 mg concentration of silver nanoparticles showed excellent inhibitory activity against all the tested pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

  14. 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.

  15. 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.

  16. Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens.

    PubMed

    Evangelista-Martínez, Zahaed

    2014-05-01

    The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90 %. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi.

  17. Pyramiding transgenic resistance in elite indica rice cultivars against the sheath blight and bacterial blight.

    PubMed

    Maruthasalam, S; Kalpana, K; Kumar, K K; Loganathan, M; Poovannan, K; Raja, J A J; Kokiladevi, E; Samiyappan, R; Sudhakar, D; Balasubramanian, P

    2007-06-01

    Elite indica rice cultivars were cotransformed with genes expressing a rice chitinase (chi11) and a thaumatin-like protein (tlp) conferring resistance to fungal pathogens and a serine-threonine kinase (Xa21) conferring bacterial blight resistance, through particle bombardment, with a view to pyramiding sheath blight and bacterial blight resistance. Molecular analyses of putative transgenic lines by polymerase chain reaction, Southern Blot hybridization, and Western Blotting revealed stable integration and expression of the transgenes in a few independent transgenic lines. Progeny analyses showed the stable inheritance of transgenes to their progeny. Coexpression of chitinase and thaumatin-like protein in the progenies of a transgenic Pusa Basmati1 line revealed an enhanced resistance to the sheath blight pathogen, Rhizoctonia solani, as compared to that in the lines expressing the individual genes. A transgenic Pusa Basmati1 line pyramided with chi11, tlp, and Xa21 showed an enhanced resistance to both sheath blight and bacterial blight.

  18. Synthesis of Novel Pyrimethanil Grafted Chitosan Derivatives with Enhanced Antifungal Activity

    PubMed Central

    Liu, Song; Xing, Ronge; Chen, Xiaolin

    2016-01-01

    In this study, three pyrimethanil grafted chitosan (PML-g-CS) derivatives were obtained. The structures of the conjugates were confirmed by FT-IR, 1H NMR, and EA. The grafting ratios were measured by HPLC. Antifungal properties of pyrimethanil grafted chitosan (PML-g-CS) derivatives against the plant pathogenic fungi Rhizoctonia solani and Gibberella zeae were investigated at concentrations of 100, 200, and 400 mg/L. The PML-g-CS derivatives showed enhanced antifungal activity in comparison with chitosan. The PML-g-CS-1 showed the best antifungal activity against R. solani, whose antifungal index was 58.32%. The PML-g-CS-2 showed the best antifungal activity against G. zeae, whose antifungal index was 53.48%. The conjugation of chitosan and pyrimethanil showed synergistic effect. The PML-g-CS derivatives we developed showed potential for further study and application in crop protection. PMID:27529072

  19. Adipose triglyceride lipase (Atgl) mediates the antibiotic jinggangmycin-stimulated reproduction in the brown planthopper, Nilaparvata lugens Stål

    PubMed Central

    Jiang, Yi-Ping; Li, Lei; Liu, Zong-Yu; You, Lin-Lin; Wu, You; Xu, Bing; Ge, Lin-Quan; Song, Qi-Sheng; Wu, Jin-Cai

    2016-01-01

    The antibiotic jinggangmycin (JGM) is an agrochemical product widely used in China for controlling rice sheath blight, Rhizoctonia solani. Unexpectedly, it stimulates reproduction in the brown planthopper (BPH), Nilaparvata lugens (Stål). However, the underlying molecular mechanisms of the stimulation are unclear. The present investigation demonstrates that adipose triglyceride lipase (Atgl) is one of the enzymes involved in the JGM-stimulated reproduction in BPH. Silence of Atgl in JGM-treated (JGM + dsAtgl) females eliminated JGM-stimulated fecundity of BPH females. In addition, Atgl knockdown significantly reduced the protein and glycerin contents in the ovaries and fat bodies of JGM + dsAtgl females required for reproduction. We conclude that Atgl is one of the key enzymes responsible for JGM-stimulated reproduction in BPH. PMID:26739506

  20. 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.

  1. 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

  2. Comparative essential oil composition and antifungal effect of bitter fennel (Foeniculum vulgare ssp. piperitum) fruit oils obtained during different vegetation.

    PubMed

    Ozcan, Mehmet Musa; Chalchat, Jean-Claude; Arslan, Derya; Ateş, Ayşe; Unver, Ahmet

    2006-01-01

    The chemical composition of the flower and unripe and ripe fruits from fennel (bitter) (Foeniculum vulgare ssp. piperitum) has been examined by gas chromatography and gas chromatography-mass spectrometry. The main identified components of the flower and unripe and ripe fruit oils were estragole (53.08%, 56.11%, and 61.08%), fenchone (13.53%, 19.18%, and 23.46%), and alpha-phellandrene (5.77%, 3.30%, and 0.72%), respectively. Minor qualitative and major quantitative variations for some compounds of essential oils were determined with respect to the different parts of F. vulgare. The oils exerted varying levels of antifungal effects on the experimental mycelial growth of Alternaria alternata, Fusarium oxysporum, and Rhizoctonia solani. The 40 ppm concentrations of fennel oils showed inhibitory effect against mycelial growth of A. alternaria, whereas 10 ppm levels were ineffective. The analyses show that fennel oils exhibited different degrees of fungistatic activity depending on the doses.

  3. Violet-Pigmented Pseudomonads With Antifungal Activity From the Rhizosphere of Beans

    PubMed Central

    Ayers, W. A.; Papavizas, G. C.

    1963-01-01

    Bean rhizosphere bacteria antagonistic to four root-infecting fungi and an antibiotic produced by these bacteria were studied. The bacteria were violet-pigmented gram-negative rods, probably belonging to the genus Pseudomonas. The antibiotic, which was localized largely in the bacterial cell mass, was easily extracted with acetone. It was selectively active against a wide variety of plant-pathogenic and saprophytic fungi tested in vitro but was relatively inactive against bacteria. The compound, partially purified by chromatography, was soluble in all organic solvents tried, but nearly insoluble in water. It demonstrated no characteristic ultraviolet- or visible-absorption spectrum and was chemically unidentified. The antagonistic bacteria or crude antibiotic applied to buried buckwheat segments suppressed the colonization of this substrate by Rhizoctonia spp. The data suggested that the bacteria or the antibiotic may play a role in the suppression of root-infecting fungi in soil. PMID:16349643

  4. Mycoparasitism studies of Trichoderma species against three phytopathogenic fungi: evaluation of antagonism and hydrolytic enzyme production.

    PubMed

    Qualhato, Thiago Fernandes; Lopes, Fabyano Alvares Cardoso; Steindorff, Andrei Stecca; Brandão, Renata Silva; Jesuino, Rosália Santos Amorim; Ulhoa, Cirano José

    2013-09-01

    Trichoderma spp. are used for biocontrol of several plant pathogens. However, their efficient interaction with the host needs to be accompanied by production of secondary metabolites and cell wall-degrading enzymes. Three parameters were evaluated after interaction between four Trichoderma species and plant-pathogenic fungi: Fusarium solani, Rhizoctonia solani and Sclerotinia sclerotiorum. Trichoderma harzianum and T. asperellum were the most effective antagonists against the pathogens. Most of the Trichoderma species produced toxic volatile metabolites, having significant effects on growth and development of the plant pathogens. When these species were grown in liquid cultures with cell walls from these plant pathogens, they produced and secreted β-1,3-glucanase, NAGAse, chitinase, acid phosphatase, acid proteases and alginate lyase.

  5. Syntheses, characterization and antifungal activity of novel dimethylbis(N-R-sulfonyldithiocarbimato)stannate(IV) complexes

    NASA Astrophysics Data System (ADS)

    Bomfim Filho, Lucius F. O.; Oliveira, Marcelo R. L.; Miranda, Liany D. L.; Vidigal, Antonio E. C.; Guilardi, Silvana; Souza, Rafael A. C.; Ellena, Javier; Ardisson, José D.; Zambolim, Laércio; Rubinger, Mayura M. M.

    2017-02-01

    Four new complexes of the general formula: (Ph4P)2[Sn(CH3)2(RSO2Ndbnd CS2)2], where Ph4P = tetraphenylphosphonium cation and R = CH3, (1), CH3CH2 (2), C6H5 (3), 4-FC6H4 (4), were prepared by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimates, K2(RSO2Ndbnd CS2), and tetraphenylphosphonium chloride with dimethyltin dichloride. The compounds 1-4 were characterized by 1H, 13C and 119Sn NMR, 119Sn Mössbauer, vibrational spectroscopy and by elemental analyses of C, H, N and Sn. The crystal structure of 1 was determined by X-ray diffraction techniques. The in vitro antifungal activity of the tin(IV) complexes were evaluated against the fungi Rhizoctonia solani and Botrytis cinerea by the Poisoned food test. The new compounds showed comparable activities to the fungicides manzate and ziram.

  6. Microwave-assisted synthesis and antifungal activity of novel fused Osthole derivatives.

    PubMed

    Zhang, Ming-Zhi; Zhang, Rong-Rong; Wang, Jia-Qun; Yu, Xiang; Zhang, Ya-Ling; Wang, Qing-Qing; Zhang, Wei-Hua

    2016-11-29

    Based on the microwave-assisted synthetic protocol developed in our previous work, we have synthesized a series of novel furo[3,2-c]coumarins as fused Osthole derivatives, via the reaction of 4-hydroxycoumarins and β-ketoesters catalyzed by DMAP. All the target compounds were evaluated in vitro for their antifungal activity against six phytopathogenic fungi, some compounds exhibited potential activity in the primary assays. Especially compounds 6c, 7b, 8b and 8c (shown in Fig. 1) were the most active ones, EC50 values of these four compounds against Colletotrichum capsica, Botrytis cinerea and Rhizoctonia solani were further investigated. 6c was identified as the most promising candidate with the EC50 value at 0.110 μM against Botrytis cinerea and 0.040 μM against Colletotrichum capsica, respectively, representing better antifungal activity than that of the commonly used fungicide Azoxystrobin.

  7. Inoculation and scoring methods for rice sheath blight disease.

    PubMed

    Jia, Yulin; Liu, Guangjie; Park, Dong-Soo; Yang, Yinong

    2013-01-01

    Sheath blight disease of rice caused by the soilborne fungal pathogen Rhizoctonia solani has been a major disease of rice with a serious threat to stable rice production worldwide. Although various cultural practices have been used to manage the disease, it is advantageous and important to screen rice germplasm and identify resistant rice cultivars for more effective disease control. Recent advances in methods for the fungal inoculation and disease evaluation have enabled a better measurement of host resistance by minimizing confounding factors from plant architectures and environmental conditions. This chapter introduces five such methods: (1) detached leaf method; (2) micro-chamber method; (3) mist-chamber method; (4) parafilm sachet method; and (5) aluminum foil method. These methods are useful for screening and evaluating disease reactions of rice germplasm and facilitating the genetic mapping of disease resistance genes.

  8. 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

  9. Effect of three nematicides on the growth of some phytopathogenic bacteria and fungi.

    PubMed

    El-Khadem, M; Mehiar, F; Embabi, M S

    1977-01-01

    The effect of three nematicides, aldicarb, fensulfothion, and phenamiphos at four concentrations (1, 5, 25, and 125 ppm) was tested on the growth of five bacteria, Agrobacterium tumefaciens, Corynebacterium fascians, Erwinia carotovora, Pseudomonas solanacearum, and Streptomyces scabies and four fungi, Fusarium oxysporum f. sp. vasinfectum, Fusarium solani, Rhizoctonia solani, and Sclerotium bataticola. Of the bacteria, P. solanacearum was most affected by the chemicals at all concentrations, while E. carotovora was least affected. Fensulfothion was generally the most effective nematicide on the bacteria tested, while phenamiphos was the least effective. Similarly, the effect of the chemicals on the fungi tested varied greatly. F. solani and R. solani were generally most affected, followed by F. oxysporum, while S. bataticola was least affected. Of the chemicals tested, phenamiphos was generally the most effective, followed by fensulfothion, while aldicarb was the least effective.

  10. The post-harvest fruit rots of tomato (Lycopersicum esculentum) in Nigeria.

    PubMed

    Fajola, A O

    1979-01-01

    A survey of the post-harvest fruit rot diseases of tomato was conducted in five states of Nigeria. During severe infections, the diseases could cause 25% loss at harvest and 34% loss of the remaining product in transit, storage and market stalls; thus giving an overall loss of about 50% of the product. Two types of rots, soft and dry were recognised. The soft rot was found to account for about 85% and the dry rot about 15% of the overall loss. Erwinia carotovora, Rhizopus oryzae, R. stolonifer, Fusarium equiseti, F. nivale and F. oxysporum were established as the soft rot pathogens; while Aspergillus aculeatus, A. flavus, Cladosporium tenuissimum, Corynespora cassiicola, Curvularia lunata, Penicillium expansum P. multicolor and Rhizoctonia solani were established as the dry rot pathogens of tomato fruits in Nigeria.

  11. 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.

  12. Synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones

    NASA Astrophysics Data System (ADS)

    Wang, H. M.; Deng, S. H.; Zheng, A. H.; Zhang, Q. Y.; Chen, X. B.; Zeng, X. H.; Hu, Y. G.

    2016-08-01

    The 3-aryl substituted thieno[2,3-d]pyrimidinones 3 by sequential reaction of iminophosphorane 1, aromatic isocyanates and various nucleophiles (HY), found some compounds showed good antitumor and antibacterial activities. Meanwhile, aliphatic isocyanates were applied in the reaction to prepare 3-alkyl substituted thieno[2,3- d]pyrimidinones, but there are no reports of their antifungal activities. As a continuation of our research for new biologically active heterocycles, we herein wish to report a facile synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones 6 via easily accessible iminophosphorane 1. The growth inhibitory effect of one concentration (50mg/L) of compounds 6 against five fungus(Fusarium oxysporium, Rhizoctonia solani, Colletotrichum gossypii, Gibberella zeae and Dothiorella gregaria) in vitro was tested by the method of toxic medium. Compound 6d showed the best inhibition rate against Gibberella zeae with 85.68%.

  13. Overexpression of Rice Wall-Associated Kinase 25 (OsWAK25) Alters Resistance to Bacterial and Fungal Pathogens

    PubMed Central

    Harkenrider, Mitch; Sharma, Rita; De Vleesschauwer, David; Tsao, Li; Zhang, Xuting; Chern, Mawsheng; Canlas, Patrick; Zuo, Shimin; Ronald, Pamela C.

    2016-01-01

    Wall-associated kinases comprise a sub-family of receptor-like kinases that function in plant growth and stress responses. Previous studies have shown that the rice wall-associated kinase, OsWAK25, interacts with a diverse set of proteins associated with both biotic and abiotic stress responses. Here, we show that wounding and BTH treatments induce OsWAK25 transcript expression in rice. We generated OsWAK25 overexpression lines and show that these lines exhibit a lesion mimic phenotype and enhanced expression of rice NH1 (NPR1 homolog 1), OsPAL2, PBZ1 and PR10. Furthermore, these lines show resistance to the hemibiotrophic pathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae, yet display increased susceptibility to necrotrophic fungal pathogens, Rhizoctonia solani and Cochliobolus miyabeanus. PMID:26795719

  14. Isolation and in vivo and in vitro antifungal activity of phenylacetic acid and sodium phenylacetate from Streptomyces humidus.

    PubMed

    Hwang, B K; Lim, S W; Kim, B S; Lee, J Y; Moon, S S

    2001-08-01

    The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae, and Pseudomonas syringae pv. syringae at concentrations from 10 to 50 microg/ml. The two compounds were as effective as the commercial fungicide metalaxyl in inhibiting spore germination and hyphal growth of P. capsici. However, the in vivo control efficacies of the two antifungal compounds against P. capsici infection on pepper plants were similar to those of H(3)PO(3) and fosetyl-AI but less than that of metalaxyl.

  15. Comparison of antifungal activity of extracts from different Juglans regia cultivars and juglone.

    PubMed

    Wianowska, D; Garbaczewska, S; Cieniecka-Roslonkiewicz, A; Dawidowicz, A L; Jankowska, A

    2016-11-01

    This study discusses the similarities and differences between the antifungal activity of extracts from walnut green husks of Lake, Koszycki, UO1, UO2 and non-grafted cultivars as well as juglone against the plant pathogenic fungi such as Alternaria alternata, Rhizoctonia solani, Botrytis cinerea, Fusarium culmorum, Phytophthora infestans as well as Ascosphaera apis causing chalkbrood disease in honey bees. The obtained data show that the antifungal activities of the extracts do not always depend on the antifungal activity of juglone, and that they can be modulated by their other components. This fact allows us to conclude that juglone is not the only component of walnut green husk extracts which is responsible for the inhibition of mycelial growth. Phenolic compounds were found to be responsible for activity of the extracts and they can modify antifungal activity of juglone.

  16. Study on Mutagenic Breeding of Bacillus Subtilis and Properties of Its Antifungal Substances

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Yao, Jianming

    2004-08-01

    Bacillus subtitles JA isolated by our laboratory produced a large amount of antifungal substances, which had strong inhibitory activity against various plant pathogenic fungi, such as Rhizoctonia solani, Fusarium graminearum and so on. Ion beam implantation as a new mutagenic methods was applied in our studay. After B. subtitles JA was implanted by N+ ions, a strain designated as B. subtitles JA-026 was screened and obtained, which had a higher ability to produce those antifungal substances. A series of experiments indicated that the antifungal substances were thermostable and partially sensitive to proteinases K and tryproteinase. When the fermentating broth was fractionated with ammonium sulphate of a final saturation of 70%, the precipitate-enhanced inhibitory activity while the supernatant lost this activity. It appeared that the antifungal substances were likely to be protein.

  17. Synthesis and Biological Evaluation of Benzimidazole Phenylhydrazone Derivatives as Antifungal Agents against Phytopathogenic Fungi.

    PubMed

    Wang, Xing; Chen, Yong-Fei; Yan, Wei; Cao, Ling-Ling; Ye, Yong-Hao

    2016-11-22

    A series of benzimidazole phenylhydrazone derivatives (6a-6ai) were synthesized and characterized by ¹H-NMR, ESI-MS, and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction as (E)-configuration. All the compounds were screened for antifungal activity against Rhizoctonia solani and Magnaporthe oryzae employing a mycelium growth rate method. Compound 6f exhibited significant inhibitory activity against R. solani and M. oryzae with the EC50 values of 1.20 and 1.85 μg/mL, respectively. In vivo testing demonstrated that 6f could effectively control the development of rice sheath blight (RSB) and rice blast (RB) caused by the above two phytopathogens. This work indicated that the compound 6f with a benzimidazole phenylhydrazone scaffold could be considered as a leading structure for the development of novel fungicides.

  18. Isolation and characterization of genetic variability in bacteria with β-hemolytic and antifungal activity isolated from the rhizosphere of Medicago truncatula plants.

    PubMed

    Hernández-Salmerón, J E; Prieto-Barajas, C M; Valencia-Cantero, E; Moreno-Hagelsieb, G; Santoyo, G

    2014-07-04

    In the present study, we analyzed the frequency of hemolytic and antifungal activities in bacterial isolates from the rhizosphere of Medicago truncatula plants. Of the 2000 bacterial colonies, 96 showed β-hemolytic activities (frequency, 4.8 x 10(-2)). Hemolytic isolates were analyzed for their genetic diversity by using random amplification of polymorphic DNA, yielding 88 haplotypes. The similarity coefficient of Nei and Li showed a polymorphic diversity ranging from 0.3 to 1. Additionally, 8 of the hemolytic isolates showed antifungal activity toward plant pathogens, Diaporthe phaseolorum, Colletotrichum acutatum, Rhizoctonia solani, and Fusarium oxysporum. The 16S ribosomal sequencing analysis showed that antagonistic bacterial isolates corresponded to Bacillus subtilis (UM15, UM33, UM42, UM49, UM52, and UM91), Bacillus pumilus (UM24), and Bacillus licheniformis (UM88). The present results revealed a higher genetic diversity among hemolytic isolates compared to that of isolates with antifungal action.

  19. Synthesis and antifungal activity evaluation of new heterocycle containing amide derivatives.

    PubMed

    Wang, Xuesong; Gao, Sumei; Yang, Jian; Gao, Yang; Wang, Ling; Tang, Xiaorong

    2016-01-01

    A series of heterocycle containing amide derivatives (1-28) were synthesised by the combination of acyl chlorides (1a, 2a) and heterocyclic/homocyclic ring containing amines, and their in vitro antifungal activity was evaluated against five plant pathogenic fungi, namely Gibberella zeae, Helminthosporium maydis, Rhizoctonia solani, Botrytis cinerea and Sclerotinia sclerotiorum. Results of antifungal activity analysis indicated that some of the products showed good to excellent antifungal activity, as compound 2 showed excellent activity against G. zeae and R. solani and potent activity against H. maydi, B. cinerea and S. sclerotiorum, and compounds 1, 8 and 10 also displayed excellent antifungal potential against H. maydi, B. cinerea and S. sclerotiorum and good activity against R. solani when compared with the standard carbendazim.

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

    PubMed

    Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek

    2014-01-03

    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.

  1. 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

  2. Synthesis and antifungal activity of the derivatives of novel pyrazole carboxamide and isoxazolol pyrazole carboxylate.

    PubMed

    Sun, Jialong; Zhou, Yuanming

    2015-03-09

    A series of pyrazole carboxamide and isoxazolol pyrazole carboxylate derivatives were designed and synthesized in this study. The structures of the compounds were elucidated based on spectral data (infrared, proton nuclear magnetic resonance and mass spectroscopy). Then, all of the compounds were bioassayed in vitro against four types of phytopathogenic fungi (Alternaria porri, Marssonina coronaria, Cercospora petroselini and Rhizoctonia solani) using the mycelium growth inhibition method. The results showed that some of the synthesized pyrazole carboxamides displayed notable antifungal activity. The isoxazole pyrazole carboxylate 7ai exhibited significant antifungal activity against R. solani, with an EC50 value of 0.37 μg/mL. Nonetheless, this value was lower than that of the commercial fungicide, carbendazol.

  3. Antifungal properties of surangin B, a coumarin from Mammea longifolia.

    PubMed

    Deng, Yanshen; Nicholson, Russell A

    2005-04-01

    The natural product electron transport inhibitor surangin B was examined for its ability to inhibit in vitro mycelial growth and spore germination in several species of fungi. As an inhibitor of mycelial growth, surangin B showed strongest activity against Rhizoctonia solani (IC50 = 3.8 microM) and Botrytis cinerea (IC50 = 11.2 microM). Inhibitory effects were less pronounced in Alternaria dauci, Fusarium oxysporum and Penicillium sp. (IC50 values > 30 microM) and absent in Trichoderma harzianum. Surangin B reduced the level of spore germination in Fusarium oxysporum (IC50 = 2.3 microM) and Botrytis cinerea (IC50 = 1.4 microM), although Alternaria dauci was considerably more tolerant of this coumarin (IC50 = 500 microM). Our results indicate that surangin B may have potential as an antifungal agent.

  4. Isolation of a new Mexican strain of Bacillus subtilis with antifungal and antibacterial activities.

    PubMed

    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.

  5. Isolation and In Vivo and In Vitro Antifungal Activity of Phenylacetic Acid and Sodium Phenylacetate from Streptomyces humidus

    PubMed Central

    Hwang, Byung Kook; Lim, Song Won; Kim, Beom Seok; Lee, Jung Yeop; Moon, Surk Sik

    2001-01-01

    The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae, and Pseudomonas syringae pv. syringae at concentrations from 10 to 50 μg/ml. The two compounds were as effective as the commercial fungicide metalaxyl in inhibiting spore germination and hyphal growth of P. capsici. However, the in vivo control efficacies of the two antifungal compounds against P. capsici infection on pepper plants were similar to those of H3PO3 and fosetyl-AI but less than that of metalaxyl. PMID:11472958

  6. Keratinolytic activities of alkaliphilic Bacillus sp. MBRL 575 from a novel habitat, limestone deposit site in Manipur, India.

    PubMed

    Kshetri, Pintubala; Ningthoujam, Debananda S

    2016-01-01

    Microbial degradation of keratinous wastes is preferred over physicochemical methods as the latter is costlier and not eco-friendly. Novel habitats are promising for discovery of new microbial strains. Towards discovery of novel keratinolytic bacteria, screening of bacterial strains from a novel limestone habitat in Hundung, Manipur, India was done and a promising isolate, MBRL 575, was found to degrade native chicken feather efficiently. It could grow over a broad pH range (Langeveld et al. in J Infect Dis 188:1782-1789, 2003; Park and Son in Microbiol Res 164:478-485, 2009; Zaghloul et al. in Biodegradation 22:111-128, 2011; Takami et al. in Biosci Biotechnol Biochem 56:1667-1669, 1992; Riffel et al. in J Biotechnol 128:693-703, 2007; Wang et al. in Bioresour Technol 99:5679-5686, 2008) and in presence of 0-15 % NaCl. Based on phenotypic characterization and 16S rRNA gene sequence analysis, the new keratinolytic limestone isolate was identified as Bacillus sp. MBRL 575. It produced 305 ± 12 U/ml keratinase and liberated 120 ± 5.5 mg of soluble peptides and 158 ± 4 mg of amino acids per gram of feather after 48 h of incubation at 30 °C in chicken feather medium. The strain could also degrade feathers of other species besides chicken. The cell-free enzyme was also able to degrade feather. Citrate and soybean meal were found to be the best carbon and nitrogen supplements for enhanced enzyme, soluble peptide and amino acid production. In addition to keratinolytic activity, MBRL 575 also exhibited antagonistic activity against two major rice fungal pathogens, Rhizoctonia oryzae-sativae (65 %) and Rhizoctonia solani (58 %).

  7. 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

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

    PubMed

    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 μ 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.

  9. 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 μ 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

  10. Biosynthesis, Chemical Structure, and Structure-Activity Relationship of Orfamide Lipopeptides Produced by Pseudomonas protegens and Related Species

    PubMed Central

    Ma, Zongwang; Geudens, Niels; Kieu, Nam P.; Sinnaeve, Davy; Ongena, Marc; Martins, José C.; Höfte, Monica

    2016-01-01

    Orfamide-type cyclic lipopeptides (CLPs) are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study, we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudomonas species. Genetic characterization together with chemical identification revealed that the main orfamide compound produced by the P. protegens group is orfamide A, while the related strains Pseudomonas sp. CMR5c and CMR12a produce orfamide B. Comparison of orfamide fingerprints led to the discovery of two new orfamide homologs (orfamide F and orfamide G) in Pseudomonas sp. CMR5c. The structures of these two CLPs were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Mutagenesis and complementation showed that orfamides determine the swarming motility of parental Pseudomonas sp. strain CMR5c and their production was regulated by luxR type regulators. Orfamide A and orfamide B differ only in the identity of a single amino acid, while orfamide B and orfamide G share the same amino acid sequence but differ in length of the fatty acid part. The biological activities of orfamide A, orfamide B, and orfamide G were compared in further bioassays. The three compounds were equally active against Magnaporthe oryzae on rice, against Rhizoctonia solani AG 4-HGI in in vitro assays, and caused zoospore lysis of Phytophthora and Pythium. Furthermore, we could show that orfamides decrease blast severity in rice plants by blocking appressorium formation in M. oryzae. Taken all together, our study shows that orfamides produced by P. protegens and related species have potential in biological control of a broad spectrum of fungal plant pathogens. PMID:27065956

  11. Changes in the soil microbial community after reductive soil disinfestation and cucumber seedling cultivation.

    PubMed

    Huang, Xinqi; Liu, Liangliang; Wen, Teng; Zhang, Jinbo; Wang, Fenghe; Cai, Zucong

    2016-06-01

    Reductive soil disinfestation (RSD) has been proven to be an effective and environmentally friendly way to control many soilborne pathogens and diseases. In this study, the RSDs using ethanol (Et-RSD) and alfalfa (Al-RSD) as organic carbons were performed in a Rhizoctonia solani-infected soil, and the dissimilarities of microbial communities during the RSDs and after planting two seasons of cucumber seedlings in the RSDs-treated soil were respectively investigated by MiSeq pyrosequencing. The results showed that, as for bacteria, Coprococcus, Flavisolibacter, Rhodanobacter, Symbiobacterium, and UC-Ruminococcaceae became the dominant bacterial genera at the end of Al-RSD. In contrast, Et-RSD soil involved more bacteria belonging to Firmicutes, such as Sedimentibacter, UC-Gracilibacteraceae, and Desulfosporosinus. For fungi, Chaetomium significantly increased at the end of RSDs, while Rhizoctonia and Aspergillus significantly decreased. After planting two seasons of cucumber seedlings, those bacteria belonging to Firmicutes significantly decreased, but Lysobacter and Rhodanobacter belonging to the phylum Proteobacteria as well as UC-Sordariales and Humicola belonging to Ascomycota alternatively increased in Al- and Et-RSD-treated soils. Besides, some nitrification, denitrification, and nitrogen fixation genes were apparently increased in the RSD-treated soils, but the effect was more profound in Al-RSD than Et-RSD. Overall, Et-RSD could induced more antagonists belonging to Firmicutes under anaerobic condition, whereas Al-RSD could continuously stimulate some functional microorganisms (Lysobacter and Rhodanobacter) and further improve nitrogen transformation activities in the soil at the coming cropping season.

  12. [Suppression of three soil-borne diseases of cucumber by a rhizosphere fungal strain].

    PubMed

    Lyu, Heng; Niu, Yong-chun; Deng, Hui; Lin, Xiao-min; Jin, Chun-li

    2015-12-01

    To understand the effect of rhizosphere fungi on soil-borne diseases of cucumber, 16 fungal, strains from rhizosphere soil were investigated for the antagonistic activity to three soilborne pathogenic fungi with dual culture method and for suppression of cucumber diseases caused by the pathogens in pot experiments. Four strains showed antagonism to one or more pathogenic fungi tested. The strain JCL143, identified as Aspergillus terreus, showed strong antagonistic activity to the three pathogenic fungi Fusarium oxysporum f. sp. cucumerinum, Rhizoctonia solani and Sclerotinia sclerotiorum. In greenhouse pot experiments, inoculation with strain JCL143 provided 74% or more of relative control effect to all the three diseases of cucumber seedling caused by the above three pathogenic fungi, and provided 85% or more of relative control effect to Rhizoctonia root rot and Sclerotinia root and stem rot in pot experiment with non-sterilized substrate. In pot experiment with natural soil as substrate, inoculation with strain JCL143 provided average 84.1% of relative control effect to Fusarium wilt of cucumber at vine elongation stage. The fermentation broth of strain JCL143 showed inhibitory effect in different degrees on the colonial growth of the three pathogenic fungi tested, and reached 63.3% of inhibitory rate of colonial growth to S. sclerotiorum. The inhibitory activity of the fermentation broth decreased with increasing treatment temperature, was liable to decrease to alkaline pH than acid pH, and stable to protease treatment. The results indicated that A. terreus is an important factor in suppression of plant soil-borne diseases, and strain JCL143 with stable disease suppression is potential in biocontrol application.

  13. 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 γ-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

  14. 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

  15. 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

  16. Enhancement of Seed Dehiscence by Seed Treatment with Talaromyces flavus GG01 and GG04 in Ginseng (Panax ginseng)

    PubMed Central

    Kim, Min-Jeong; Shim, Chang-Ki; Kim, Yong-Ki; Hong, Sung-Jun; Park, Jong-Ho; Han, Eun-Jung; Kim, Seok-Cheol

    2017-01-01

    Seed dehiscence of ginseng (Panax ginseng C. A. Mayer) is affected by moisture, temperature, storage conditions and microbes. Several microbes were isolated from completely dehisced seed coat of ginseng cultivars, Chunpoong and Younpoong at Gumsan, Korea. We investigated the potential of five Talaromyces flavus isolates from the dehiscence of ginseng seed in four traditional stratification facilities. The isolates showed antagonistic activities against fungal plant pathogens, such as Cylindrocarpon destructans, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia nivalis, Botrytis cinerea, and Phytophthora capsici. The dehiscence ratios of ginseng seed increased more than 33% by treatment of T. flavus GG01, GG02, GG04, GG12, and GG23 in comparison to control (28%). Among the treatments, the reformulating treatment of T. flavus isolates GG01 and GG04 showed the highest of stratification ratio of ginseng seed. After 16 weeks, the reformulating treatment of T. flavus isolates GG01 and GG04 significantly enhanced dehiscence of ginseng seed by about 81% compared to the untreated control. The candidate’s treatment of T. flavus GG01 and GG04 showed the highest decreasing rate of 93% in seed coat hardness for 112 days in dehiscence period. The results suggested that the pre-inoculation of T. flavus GG01 and GG04 found to be very effective applications in improving dehiscence and germination of ginseng seed. PMID:28167883

  17. Influence of host plant genotype, presence of a pathogen, and coinoculation with Pseudomonas fluorescens strains on the rhizosphere expression of hydrogen cyanide- and 2,4-diacetylphloroglucinol biosynthetic genes in P. fluorescens biocontrol strain CHA0.

    PubMed

    Jamali, Fatemeh; Sharifi-Tehrani, Abbas; Lutz, Matthias P; Maurhofer, Monika

    2009-02-01

    The production of hydrogen cyanide (HCN) and 2,4-diacetylphloroglucinol (DAPG) is a major factor in the control of soil-borne diseases by Pseudomonas fluorescens CHA0. We investigated the impact of different biotic factors on the expression of HCN-in comparison to DAPG biosynthetic genes in the rhizosphere. To this end, the influence of plant cultivar, pathogen infection, and coinoculation with other biocontrol strains on the expression of hcnA-lacZ and phlA-lacZ fusion in strain CHA0 was monitored on the roots of bean. Interestingly, all the tested factors influenced the expression of the two biocontrol traits in a similar way. For both genes, we observed a several-fold higher expression in the rhizosphere of cv. Derakhshan compared with cvs. Goli and Naz, although bacterial rhizosphere colonization levels were similar on all cultivars tested. Root infection by Rhizoctonia solani stimulated total phlA and hcnA gene expression in the bean rhizosphere. Coinoculation of strain CHA0 with DAPG-producing P. fluorescens biocontrol strains Pf-68 and Pf-100 did neither result in a substantial alteration of hcnA nor of phlA expression in CHA0 on bean roots. To our best knowledge, this is the first study investigating the impact of biotic factors on HCN production by a bacterial biocontrol strain in the rhizosphere.

  18. 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.

  19. Impact of soil heat on reassembly of bacterial communities in the rhizosphere microbiome and plant disease suppression.

    PubMed

    van der Voort, Menno; Kempenaar, Marcel; van Driel, Marc; Raaijmakers, Jos M; Mendes, Rodrigo

    2016-04-01

    The rhizosphere microbiome offers a range of ecosystem services to the plant, including nutrient acquisition and tolerance to (a)biotic stress. Here, analysing the data by Mendes et al. (2011), we show that short heat disturbances (50 or 80 °C, 1 h) of a soil suppressive to the root pathogenic fungus Rhizoctonia solani caused significant increase in alpha diversity of the rhizobacterial community and led to partial or complete loss of disease protection. A reassembly model is proposed where bacterial families that are heat tolerant and have high growth rates significantly increase in relative abundance after heat disturbance, while temperature-sensitive and slow-growing bacteria have a disadvantage. The results also pointed to a potential role of slow-growing, heat-tolerant bacterial families from Actinobacteria and Acidobacteria phyla in plant disease protection. In conclusion, short heat disturbance of soil results in rearrangement of rhizobacterial communities and this is correlated with changes in the ecosystem service disease suppression.

  20. The role of antioxidant enzymes in adaptive responses to sheath blight infestation under different fertilization rates and hill densities.

    PubMed

    Wu, Wei; 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.

  1. Antibacterial and Antifungal Studies on Some Schiff Base Complexes of Zinc(II).

    PubMed

    Joseyphus, R Selwin; Nair, M Sivasankaran

    2008-06-01

    Two Schiff base ligands L1and L2 were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1: 1electrolytes. The IR data demonstrate the tetradentate binding of L1and tridentate binding of L2. The XRD data show that Zn(II) complexes with L1and L2 have the crystallite sizes of 53 and 61nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven 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.

  2. Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12.

    PubMed

    Ryder, Lauren S; Harris, Beverley D; Soanes, Darren M; Kershaw, Michael J; Talbot, Nicholas J; Thornton, Christopher R

    2012-01-01

    Trichoderma species are ubiquitous soil fungi that hold enormous potential for the development of credible alternatives to agrochemicals and synthetic fertilizers in sustainable crop production. In this paper, we show that substantial improvements in plant productivity can be met by genetic modification of a plant-growth-promoting and biocontrol strain of Trichoderma hamatum, but that these improvements are obtained in the absence of disease pressure only. Using a quantitative monoclonal antibody-based ELISA, we show that an N-acetyl-β-d-glucosaminidase-deficient mutant of T. hamatum, generated by insertional mutagenesis of the corresponding gene, has impaired saprotrophic competitiveness during antagonistic interactions with Rhizoctonia solani in soil. Furthermore, its fitness as a biocontrol agent of the pre-emergence damping-off pathogen Sclerotinia sclerotiorum is significantly reduced, and its ability to promote plant growth is constrained by the presence of both pathogens. This work shows that while gains in T. hamatum-mediated plant-growth-promotion can be met through genetic manipulation of a single beneficial trait, such a modification has negative impacts on other aspects of its biology and ecology that contribute to its success as a saprotrophic competitor and antagonist of soil-borne pathogens. The work has important implications for fungal morphogenesis, demonstrating a clear link between hyphal architecture and secretory potential. Furthermore, it highlights the need for a holistic approach to the development of genetically modified Trichoderma strains for use as crop stimulants and biocontrol agents in plant agriculture.

  3. Effects of Rapeseed and Vetch as Green Manure Crops and Fallow on Nematodes and Soil-borne Pathogens

    PubMed Central

    Johnson, A. W.; Golden, A. M.; Auld, D. L.; Sumner, D. R.

    1992-01-01

    In a rapeseed-squash cropping system, Meloidogyne incognita race 1 and M. javanica did not enter, feed, or reproduce in roots of seven rapeseed cultivars. Both nematode species reproduced at low levels on roots of the third crop of rapeseed. Reproduction of M. incognita and M. javanica was high on squash following rapeseed, hairy vetch, and fallow. The application of fenamiphos suppressed (P = 0.05) root-gall indices on squash following rapeseed, hairy vetch, and fallow; and on Dwarf Essex and Cascade rapeseed, but not Bridger and Humus rapeseed in 1987. The incorporation of 30-61 mt/ha green biomass of rapeseed into the soil 6 months after planting did not affect the population densities of Criconemella ornata, M. incognita, M. javanica, Pythium spp., Rhizoctonia solani AG-4; nor did it consistently increase yield of squash. Hairy vetch supported larger numbers of M. incognita and M. javanica than rapeseed cultivars or fallow. Meloidogyne incognita and M. javanica survived in fallow plots in the absence of a host from October to May each year at a level sufficient to warrant the use of a nematicide to manage nematodes on the following susceptible crop. PMID:19283212

  4. Novel copper-based therapeutic agent for anti-inflammatory: synthesis, characterization, and biochemical activities of copper(II) complexes of hydroxyflavone Schiff bases.

    PubMed

    Joseph, J; Nagashri, K

    2012-07-01

    Four hydroxyflavone derivatives have been synthesized with the aim of obtaining a good model of superoxide dismutase. Better to mimic the natural metalloenzyme, copper complexes have been designed. The Cu(II) complexes of general formulae, [CuL] where L = 5-hydroxyflavone-o-phenylenediamine (L¹H₂)/m-phenylenediamine (L²H₂) and 3-hydroxyflavone-o-phenylenediamine (L³H₂)/m-phenylenediamine (L⁴H₂) have been synthesized. The structural features have been determined from their analytical and spectral data. All the Cu(II) complexes exhibit square planar geometry. Redox behavior of copper complexes was studied and the present ligand systems stabilize the unusual oxidation state of the copper ion during electrolysis. The in vitro antimicrobial activities 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. Superoxide dismutase and anti-inflammatory activities of the copper complexes have also been measured and discussed.

  5. Evaluation of Nostoc strain ATCC 53789 as a potential source of natural pesticides.

    PubMed

    Biondi, Natascia; Piccardi, Raffaella; Margheri, M Cristina; Rodolfi, Liliana; Smith, Geoffrey D; Tredici, Mario R

    2004-06-01

    The cyanobacterium Nostoc strain ATCC 53789, a known cryptophycin producer, was tested for its potential as a source of natural pesticides. The antibacterial, antifungal, insecticidal, nematocidal, and cytotoxic activities of methanolic extracts of the cyanobacterium were evaluated. Among the target organisms, nine fungi (Armillaria sp., Fusarium oxysporum f. sp. melonis, Penicillium expansum, Phytophthora cambivora, P. cinnamomi, Rhizoctonia solani, Rosellinia, sp., Sclerotinia sclerotiorum, and Verticillium albo-atrum) were growth inhibited and one insect (Helicoverpa armigera) was killed by the extract, as well as the two model organisms for nematocidal (Caenorhabditis elegans) and cytotoxic (Artemia salina) activity. No antibacterial activity was detected. The antifungal activity against S. sclerotiorum was further studied with both extracts and biomass of the cyanobacterium in a system involving tomato as a host plant. Finally, the herbicidal activity of Nostoc strain ATCC 53789 was evaluated against a grass mixture. To fully exploit the potential of this cyanobacterium in agriculture as a source of pesticides, suitable application methods to overcome its toxicity toward plants and nontarget organisms must be developed.

  6. Characterization of the volatile constituents in the essential oil of Pistacia lentiscus L. from different origins and its antifungal and antioxidant activity.

    PubMed

    Barra, Andrea; Coroneo, Valentina; Dessi, Sandro; Cabras, Paolo; Angioni, Alberto

    2007-08-22

    Essential oil (EO) from aerial parts (leaves, juvenile branches, and flowers when present) of Pistacia lentiscus L. growing wild in five localities of Sardinia (Italy) was extracted by steam-distillation (SD) and analyzed by gas chromatography (GC), FID, and GC-ion trap mass spectrometry (ITMS). Samples of P. lentiscus L. were harvested between April and October to study the seasonal chemical variability of the EO. A total of 45 compounds accounting for 97.5-98.4% of the total EO were identified, and the major compounds were alpha-pinene (14.8-22.6%), beta-myrcene (1-19.4%), p-cymene (1.6-16.2%), and terpinen-4-ol (14.2-28.3%). The yields of EO (v/dry w) ranged between 0.09 and 0.32%. Similar content of the major compounds was found in samples from different origins and seasonal variability was also observed. The EOs were tested for their antifungal activity against Aspergillus flavus, Rhizoctonia solani, Penicillium commune, Fusarium oxysporum. Two samples were weakly effective against Aspergillus flavus. Furthermore, terpinenol and alpha-terpineol, two of the major components of EO of Pistacia lentiscus L., totally inhibited the mycelian growth of A. flavus. Quite good antioxidant activity of the EO was also found.

  7. Isolation and Characterization of a Bacteriophage Preying an Antifungal Bacterium.

    PubMed

    Rahimi-Midani, Aryan; Kim, Kyoung-Ho; Lee, Seon-Woo; Jung, Sang Bong; Choi, Tae-Jin

    2016-12-01

    Several Bacillus species were isolated from rice field soils, and 16S rRNA gene sequence analysis showed that Bacillus cereus was the most abundant. A strain named BC1 showed antifungal activity against Rhizoctonia solani. Bacteriophages infecting strain BC1 were isolated from the same soil sample. The isolated phage PK16 had an icosahedral head of 100 ± 5 nm and tail of 200 ± 5 nm, indicating that it belonged to the family Myoviridae. Analysis of the complete linear dsDNA genome revealed a 158,127-bp genome with G + C content of 39.9% comprising 235 open reading frames as well as 19 tRNA genes (including 1 pseudogene). Blastp analysis showed that the proteins encoded by the PK16 genome had the closest hits to proteins of seven different bacteriophages. A neighbor-joining phylogenetic tree based on the major capsid protein showed a robust clustering of phage PK16 with phage JBP901 and BCP8-2 isolated from Korean fermented food.

  8. 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.

  9. Metagenomic Analysis of Fungal Diversity on Strawberry Plants and the Effect of Management Practices on the Fungal Community Structure of Aerial Organs

    PubMed Central

    Abdelfattah, Ahmed; Wisniewski, Michael; Li Destri Nicosia, Maria Giulia; Cacciola, Santa Olga

    2016-01-01

    An amplicon metagenomic approach based on the ITS2 region of fungal rDNA was used to identify the composition of fungal communities associated with different strawberry organs (leaves, flowers, immature and mature fruits), grown on a farm using management practices that entailed the routine use of various chemical pesticides. ITS2 sequences clustered into 316 OTUs and Ascomycota was the dominant phyla (95.6%) followed by Basidiomycota (3.9%). Strawberry plants supported a high diversity of microbial organisms, but two genera, Botrytis and Cladosporium, were the most abundant, representing 70–99% of the relative abundance (RA) of all detected sequences. According to alpha and beta diversity analyses, strawberry organs displayed significantly different fungal communities with leaves having the most diverse fungal community, followed by flowers, and fruit. The interruption of chemical treatments for one month resulted in a significant modification in the structure of the fungal community of leaves and flowers while immature and mature fruit were not significantly affected. Several plant pathogens of other plant species, that would not be intuitively expected to be present on strawberry plants such as Erysiphe, were detected, while some common strawberry pathogens, such as Rhizoctonia, were less evident or absent. PMID:27490110

  10. Salivary syndrome in horses: identification of slaframine in red clover hay.

    PubMed Central

    Hagler, W M; Behlow, R F

    1981-01-01

    An outbreak of salivary syndrome in horses in North Carolina was investigated. Rhizoctonia leguminicola was the predominant fungus isolated from toxic red clover hay. The fungus was less prevalent in the hay after 10 months of storage, and the hay had also decreased in biological activity after 10 months. Toxic hay caused extreme salivation, piloerection, respiratory distress, and increased frequency of defecation when fed to guinea pigs, and purified extracts of toxic hay and pure slaframine elicited these same responses when injected intraperitoneally into guinea pigs. The freshly acquired hay, based on the biological (slobber-producing) activity in hay and in purified extracts, contained the equivalent to 50 to 100 ppm (50 to 100 microgram/g) of slaframine, but this level had decreased after 10 months by about 10-fold to about 7 ppm. Slaframine and seven synthetic derivates of slaframine were used in presumptive gas-liquid chromatographic identification of this mycotoxin. Slaframine (1-acetoxy-6-amino-octahydroindolizine) was identified in purified extracts of toxic hay by gas-liquid chromatography-mass spectrometry after preparative thin-layer chromatography. This was the first direct identification of slaframine in toxic red clove hay. PMID:7316513

  11. Microbiome Networks: A Systems Framework for Identifying Candidate Microbial Assemblages for Disease Management.

    PubMed

    Poudel, R; Jumpponen, A; Schlatter, D C; Paulitz, T C; Gardener, B B McSpadden; Kinkel, L L; Garrett, K A

    2016-10-01

    Network models of soil and plant microbiomes provide new opportunities for enhancing disease management, but also challenges for interpretation. We present a framework for interpreting microbiome networks, illustrating how observed network structures can be used to generate testable hypotheses about candidate microbes affecting plant health. The framework includes four types of network analyses. "General network analysis" identifies candidate taxa for maintaining an existing microbial community. "Host-focused analysis" includes a node representing a plant response such as yield, identifying taxa with direct or indirect associations with that node. "Pathogen-focused analysis" identifies taxa with direct or indirect associations with taxa known a priori as pathogens. "Disease-focused analysis" identifies taxa associated with disease. Positive direct or indirect associations with desirable outcomes, or negative associations with undesirable outcomes, indicate candidate taxa. Network analysis provides characterization not only of taxa with direct associations with important outcomes such as disease suppression, biofertilization, or expression of plant host resistance, but also taxa with indirect associations via their association with other key taxa. We illustrate the interpretation of network structure with analyses of microbiomes in the oak phyllosphere, and in wheat rhizosphere and bulk soil associated with the presence or absence of infection by Rhizoctonia solani.

  12. Effects of plant genotype and growth stage on the structure of bacterial communities associated with potato (Solanum tuberosum L.).

    PubMed

    van Overbeek, Leo; van Elsas, Jan Dirk

    2008-05-01

    The effects of genotype, plant growth and experimental factors (soil and year) on potato-associated bacterial communities were studied. Cultivars Achirana Inta, Désirée, Merkur and transgenic Désirée line DL12 (containing T4 lysozyme gene) were assessed in two field experiments. Cross-comparisons between both experiments were made using Désirée plants. Culture-dependent and -independent approaches were used to demonstrate effects on total bacterial, actinobacterial and Pseudomonas communities in bulk and rhizosphere soils and endospheres. PCR-denaturing gradient gel electrophoresis fingerprints prepared with group-specific primers were analyzed using multivariate analyses and revealed that bacterial communities in Achirana Inta plants differed most from those of Désirée and Merkur. No significant effects were found between Désirée and DL12 lines. Plant growth stage strongly affected different plant-associated communities in both experiments. To investigate the effect of plant-associated communities on plant health, 800 isolates from rhizospheres and endospheres at the flowering stage were tested for suppression of Ralstonia solanacearum biovar 2 and/or Rhizoctonia solani AG3. A group of isolates closely resembling Lysobacter sp. dominated in young plants. Its prevalence was affected by plant growth stage and experiment rather than by plant genotype. It was concluded that plant growth stage overwhelmed any effect of plant genotype on the bacterial communities associated with potato.

  13. The Transcription Factor OsWRKY45 Negatively Modulates the Resistance of Rice to the Brown Planthopper Nilaparvata lugens

    PubMed Central

    Huangfu, Jiayi; Li, Jiancai; Li, Ran; Ye, Meng; Kuai, Peng; Zhang, Tongfang; Lou, Yonggen

    2016-01-01

    WRKY transcription factors play a central role not only in plant growth and development but also in plant stress responses. However, the role of WRKY transcription factors in herbivore-induced plant defenses and their underlying mechanisms, especially in rice, remains largely unclear. Here, we cloned a rice WRKY gene OsWRKY45, whose expression was induced by mechanical wounding, by infestation of the brown planthopper (BPH, Nilaparvata lugens) and by treatment with jasmonic acid (JA) or salicylic acid (SA). The antisense expression of OsWRKY45 (as-wrky) enhanced BPH-induced levels of H2O2 and ethylene, reduced feeding and oviposition preference as well as the survival rate of BPH, and delayed the development of BPH nymphs. Consistently, lower population densities of BPH on as-wrky lines, compared to those on wild-type (WT) plants, were observed in field experiments. On the other hand, as-wrky lines in the field had lower susceptibility to sheath blight (caused by Rhizoctonia solani) but higher susceptibility to rice blast (caused by Magnaporthe oryzae) than did WT plants. These findings suggest that OsWRKY45 plays important but contrasting roles in regulating the resistance of rice to pathogens and herbivores, and attention should be paid if OsWRKY45 is used to develop disease or herbivore-resistant rice. PMID:27258255

  14. Molecular cloning, characterization, and expression of a chitinase from the entomopathogenic fungus Paecilomyces javanicus.

    PubMed

    Chen, Chien-Cheng; Kumar, H G Ashok; Kumar, Senthil; Tzean, Shean-Shong; Yeh, Kai-Wun

    2007-07-01

    Paecilomyces javanicus is an entomopathogenic fungus of coleopteran and lepidopteran insects. Here we report on cloning, characterization, and expression patterns of a chitinase from P. javanicus. A strong chitinase activity was detected in P. javanicus cultures added to chitin. The full-length cDNA, designated PjChi-1, was cloned from mycelia by using both degenerate primer/reverse transcription polymerase chain reaction (RT-PCR) amplification and 5'-/3'-RACE extension. The 1.18-kb cDNA gene contains a 1035-bp open reading frame and encodes a 345-amino acid polypeptide with a deduced molecular mass of 37 kDa. A conserved motif for chitinase activity -F82DGIDIDWE90- was present in deduced amino acid sequence. Both RT-PCR and Northern analysis revealed that the expression of the PjChi gene was constitutive at low level, but enhanced to high level when chitin was the substrate. Fungal inhibitory assay showed that PjChi-1 inhibited the growth of phytopathogenic fungi such as Sclerotium rolfsii, Colletotrichum gloeosporioides, Aspergillus nidulans, and Rhizoctonia solani.

  15. 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

    2015-11-25

    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.

  16. Preparation and evaluation of Bacillus megaterium-alginate microcapsules for control of rice sheath blight disease.

    PubMed

    Wiwattanapatapee, R; Chumthong, A; Pengnoo, A; Kanjanamaneesathian, M

    2013-08-01

    Bacillus megaterium encapsulated in calcium alginate microcapsules was prepared and tested for its efficacy against sheath blight disease of rice. In laboratory conditions, the aqueous suspension (1:100, v/v in potato dextrose agar) of the bacterial microcapsules (10(10) spores/ml) inhibited mycelial growth of Rhizoctonia solani (>99 %) after the microcapsules were produced and stored for 12 months at room temperature (28 ± 2 °C). The survival of the bacterium in the microcapsules in response to ultraviolet (u.v.) irradiation and high temperature was investigated. The survivability of the bacterium in the encapsulated form was greater than that of the fresh cells when it was subjected to u.v. (20-W General electric u.v. lamp from a 25 cm distance for 48 h) and a high temperature treatment (80 °C for 48 h). Cells of the bacterium were detected by scanning electron microscope on both the leaf sheath and the leaf blade (in pot tests in a greenhouse) after spraying encapsulated product. The number of bacteria on the surface of both rice tissues (5 Log. number/g of plant) after spraying with encapsulated product was not significantly different from that after spraying with fresh cells onto the rice seedlings. Spraying the encapsulated B. megaterium on rice plants in the greenhouse was as effective as spraying a chemical fungicide for suppressing rice sheath blight disease.

  17. Implementation of bio-fungicides and seed treatment in organic rice cv. KDML 105 farming.

    PubMed

    Thobunluepop, Pitipong

    2009-08-15

    This study was aimed to evaluate the several chemical compounds of relatively composite structure with antifungal activity from Thai local medical plants. The antifungal activity of Stemona curtisii HK. f., Stemona tuberose L., Acorus calamus L., Eugenia caryophyllus, Memmea siamensis Kost. and an eugenol active compound were studied in vitro. Four pathogenic seed borne fungi, Alternaria solani, Colletotrichum sp., Fusarium moniliforme and Rhizoctonia solani were used as target organisms. The agar overlay technique and spore inhibition techniques were applied for the determination of their essential oil and active compound antifungal activity at various concentration; 0.10, 0.25, 0.50 and 1.00% (v/v) and untreated as control (0% v/v). Eugenol active compound showed the strongest antifungal activity on all species of tested fungal species. On the other hand, the antifungal activity of those bio-fungicides was lined up into a series from strong to low, as follows: Eugenia caryophyllus > Acorus calamus Linn. > Stemona tuberosa L. > Stemona curtisii Hk.f, while Mammea siamensis Kost. could not control any fungal species. Moreover, after eugenol application, lysis of spore and inhibition of mycelium growth were detected. Microscopic analysis exhibited complete lysis of spores after 24 h at a concentration of 1.00% v/v. Moreover, at the same concentration and 96 h incubation the mycelia growth was completely inhibited.

  18. Genetic parameters and correlations of collar rot resistance with important biochemical and yield traits in opium poppy (Papaver somniferum L.).

    PubMed

    Trivedi, Mala; Tiwari, Rajesh K; Dhawan, Om P

    2006-01-01

    Collar rot, caused by Rhizoctonia solani Kühn, is one of the most severe fungal diseases of opium poppy. In this study, heritability, genetic advance and correlation for 10 agronomic, 1 physiological, 3 biochemical and 1 chemical traits with disease severity index (DSI) for collar rot were assessed in 35 accessions of opium poppy. Most of the economically important characters, like seed and capsule straw yield per plant, oil and protein content of seeds, peroxidase activity in leaves, morphine content of capsule straw and DSI for collar rot showed high heritability as well as genetic advance. Highly significant negative correlation between DSI and seed yield clearly shows that as the disease progresses in plants, seed yield declines, chiefly due to premature death of infected plants as well as low seed and capsule setting in the survived population of susceptible plants. Similarly, a highly significant negative correlation between peroxidase activity and DSI indicated that marker-assisted selection of disease-resistant plants based on high peroxidase activity would be effective and survived susceptible plants could be removed from the population to stop further spread.

  19. [Induction, purification and antifungal activity of beta-1, 3-glucanase from wheat leaves].

    PubMed

    Sun, Bin; Li, Duo-Chuan; Ci, Xiao-Yan; Guo, Run-Fang; Wang, Ying

    2004-08-01

    Treatment with mercuric chloride (0.01%), salicylic acid (10.0 mg/mL) or riboflavin (1 mmol/L) induced the beta-1, 3-glucanase activity in all the three wheat varieties i.e. 331, Kangdao 680 and Lumai 23 tested, with the strongest inductive effect on variety 331 by treatment with mercuric chloride (0.01%) for 24 h. From leaves of variety 331 treated with mercuric chloride (0.01%) for 24 h, a kind of beta-1, 3-glucanase was purified by fractional precipitation with ammonium sulphate, Phenyl-Sepharose chromatography (Phenyl-Sepharose Fast Flow), ion-exchange chromatography (DEAE-Sepharose Fast Flow) and gel-filtration chromatography (Sephacryl S-100). Through SDS-PAGE and gel filtration, the molecular weight of the purified beta-1, 3-glucanase was determined to be about 52.0-53.6 kD. The purified beta-1, 3-glucanase showed antifungal activity against both Alternaria longipes and Rhizoctonia cerealis on tested plates, and inhibited the germ tube elongation and spore germination of Verticillium dahliae and Fusarium omysporum f.sp cucumerinum.

  20. Synthesis and antifungal activity of 2-allylphenol derivatives against fungal plant pathogens.

    PubMed

    Qu, Tianli; Gao, Shumei; Li, Jianqiang; Hao, Jianjun J; Ji, Pingsheng

    2017-01-01

    2-Allylphenol (2-AP) is an effective fungicide against a number of plant pathogens, which can be metabolized and bio-transformed to four chemical compounds by Rhizoctonia cerealis. To determine if its degradation affects antifungal activity, two major metabolites derived from 2-AP including 2-(2-hydroxypropyl) phenol and 2-(3-hydroxypropyl) phenol were synthesized. Inhibition of mycelial growth of several plant pathogens by the metabolites was evaluated, and structures of two metabolites were determined by hydrogen nuclear magnetic resonance ((1)H NMR). Among these metabolites, only 2-(2-hydroxypropyl) phenol inhibited test pathogens effectively. EC50 values of 2-(2-hydroxypropyl) phenol for inhibition of mycelial growth of R. cerealis, Pythium aphanidermatum, Valsa mali and Botrytis cinerea ranged from 1.0 to 23.5μg/ml, which were lower than the parental fungicide 2-AP that ranged from 8.2 to 48.8μg/ml. Hyphae of R. cerealis and P. aphanidermatum treated with 2-(2-hydroxypropyl) phenol were twisted. Newly developed hyphae were slender, twisted and swollen on the tip, while old hyphae were hollow and ruptured. This is the first report indicating the formation of 2-(2-hydroxypropyl) phenol may have contributed to toxicity of 2-allylphenol in control of plant pathogens.

  1. Phytogenic synthesis of silver nanoparticles, optimization and evaluation of in vitro antifungal activity against human and plant pathogens.

    PubMed

    Balashanmugam, P; Balakumaran, M D; Murugan, R; Dhanapal, K; Kalaichelvan, P T

    2016-11-01

    An attempt was made to synthesis of biocompatible silver nanoparticles from ten different Cassia spp. Among them, Cassia roxburghii aqueous leaf extract supported the synthesis of highly efficient and stable AgNPs. The synthesis of AgNPs was optimized at different physico-chemical condition and highly stable AgNPs were synthesized with 1.0mL of C. roxburghii leaf extract, pH 7.0, 1.0mM AgNO3 and at 37°C. The synthesized AgNPs were characterized by XPS, DLS and ZETA potential. DLS and ZETA potential analysis, the average AgNPs size was 35nm and the zeta potential was -18.3mV. The AgNPs exhibit higher antifungal activity when compared with the conventional antifungal drug amphotericin B against all the tested human fungal pathogens such as Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Penicillium sp., Candida albicans and the plant pathogens such as Rhizoctonia solani, Fusarium oxysporum and Curvularia sp. Scanning electron microscope (SEM) analysis showed distinct structural changes in the cell membranes of C. albicans upon AgNPs treatment. These results suggest that phytosynthesized AgNPs could be used as effective growth inhibitors in controlling various human and plant diseases caused by fungi.

  2. Lactoferrin-derived resistance against plant pathogens in transgenic plants.

    PubMed

    Lakshman, Dilip K; Natarajan, Savithiry; Mandal, Sudhamoy; Mitra, Amitava

    2013-12-04

    Lactoferrin (LF) is a ubiquitous cationic iron-binding milk glycoprotein that contributes to nutrition and exerts a broad-spectrum primary defense against bacteria, fungi, protozoa, and viruses in mammals. These qualities make lactoferrin protein and its antimicrobial motifs highly desirable candidates to be incorporated in plants to impart broad-based resistance against plant pathogens or to economically produce them in bulk quantities for pharmaceutical and nutritional purposes. This study introduced bovine LF (BLF) gene into tobacco ( Nicotiana tabacum var. Xanthi), Arabidopsis ( A. thaliana ) and wheat ( Triticum aestivum ) via Agrobacterium -mediated plant transformation. Transgenic plants or detached leaves exhibited high levels of resistance against the damping-off causing fungal pathogen Rhizoctonia solani and the head blight causing fungal pathogen Fusarium graminearum . LF also imparted resistance to tomato plants against a bacterial pathogen, Ralstonia solanacearum . Similarly, other researchers demonstrated expression of LF and LF-mediated high-quality resistance to several other aggressive fungal and bacterial plant pathogens in transgenic plants and against viral pathogens by foliar applications of LF or its derivatives. Taken together, these studies demonstrated the effectiveness of LF for improving crop quality and its biopharming potentials for pharmaceautical and nutritional applications.

  3. Decolorization of synthetic brilliant green carpet industry dye through fungal co-culture technology.

    PubMed

    Kumari, Simpal; Naraian, Ram

    2016-09-15

    Aim of the present study was to evaluate the efficiency of fungal co-culture for the decolorization of synthetic brilliant green carpet industry dye. For this purpose two lignocellulolytic fungi Pleurotus florida (PF) and Rhizoctonia solani (RS) were employed. The study includes determination of enzyme profiles (laccase and peroxidase), dye decolorization efficiency of co-culture and crude enzyme extracts. Both fungi produced laccase and Mn peroxidase and successfully decolorized solutions of different concentrations (2.0, 4.0, 6.0, & 8.0(w/v) of dye. The co-culture resulted highest 98.54% dye decolorization at 2% (w/v) of dye as compared to monocultures (82.12% with PF and 68.89% with RS) during 12 days of submerged fermentation. The lower levels of dyes were rapidly decolorized, while higher levels in slow order as 87.67% decolorization of 8% dye. The promising achievement of the study was remarkable decolorizing efficiency of co-culture over monocultures. The direct treatment of the mono and co-culture enzyme extracts to dye also influenced remarkable. The highest enzymatic decolorization was through combined (PF and RS) extracts, while lesser by monoculture extracts. Based on the observations and potentiality of co-culture technology; further it can be exploited for the bioremediation of areas contaminated with hazardous environmental pollutants including textile and other industry effluents.

  4. 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

  5. Phytophthora capsici Epidemic Dispersion on Commercial Pepper Fields in Aguascalientes, Mexico

    PubMed Central

    Zapata-Vázquez, Adrián; Sánchez-Sánchez, Mario; del-Río-Robledo, Alicia; Silos-Espino, Héctor; Perales-Segovia, Catarino; Flores-Benítez, Silvia; González-Chavira, Mario Martín; Valera-Montero, Luis Lorenzo

    2012-01-01

    Chili pepper blight observed on pepper farms from north Aguascalientes was monitored for the presence of Phytophthora capsici during 2008–2010. Initially, ELISA tests were directed to plant samples from greenhouses and rustic nurseries, showing an 86% of positive samples. Later, samples of wilted plants from the farms during the first survey were tested with ELISA. The subsequent survey on soil samples included mycelia isolation and PCR amplification of a 560 bp fragment of ITS-specific DNA sequence of P. capsici. Data was analyzed according to four geographical areas defined by coordinates to ease the dispersal assessment. In general, one-third of the samples from surveyed fields contained P. capsici, inferring that this may be the pathogen responsible of the observed wilt. Nevertheless, only five sites from a total of 92 were consistently negative to P. capsici. The presence of this pathogen was detected through ELISA and confirmed through PCR. The other two-thirds of the negative samples may be attributable to Fusarium and Rhizoctonia, both isolated instead of Phytophthora in these areas. Due to these striking results, this information would be of interest for local plant protection committees and farmers to avoid further dispersal of pathogens to new lands. PMID:22629131

  6. Genetic modification of potato against microbial diseases: in vitro and in planta activity of a dermaseptin B1 derivative, MsrA2.

    PubMed

    Osusky, Milan; Osuska, Lubica; Kay, William; Misra, Santosh

    2005-08-01

    Dermaseptin B1 is a potent cationic antimicrobial peptide found in skin secretions of the arboreal frog Phyllomedusa bicolor. A synthetic derivative of dermaseptin B1, MsrA2 (N-Met-dermaseptin B1), elicited strong antimicrobial activities against various phytopathogenic fungi and bacteria in vitro. To assess its potential for plant protection, MsrA2 was expressed at low levels (1-5 microg/g of fresh tissue) in the transgenic potato (Solanum tuberosum L.) cv. Desiree. Stringent challenges of these transgenic potato plants with a variety of highly virulent fungal phytopathogens--Alternaria, Cercospora, Fusarium, Phytophthora, Pythium, Rhizoctonia and Verticillium species--and with the bacterial pathogen Erwinia carotovora demonstrated that the plants had an unusually broad-spectrum and powerful resistance to infection. MsrA2 profoundly protected both plants and tubers from diseases such as late blight, dry rot and pink rot and markedly extended the storage life of tubers. Due to these properties in planta, MsrA2 is proposed as an ideal antimicrobial peptide candidate to significantly increase resistance to phytopathogens and improve quality in a variety of crops worldwide with the potential to obviate fungicides and facilitate storage under difficult conditions.

  7. Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem/leaves and flowers.

    PubMed

    Angioni, Alberto; Barra, Andrea; Coroneo, Valentina; Dessi, Sandro; Cabras, Paolo

    2006-06-14

    Essential oils from the stems/leaves (L) and flowers (F) of Lavandula stoechas L. ssp. stoechas growing wild in southern Sardinia (Italy) were extracted by hydrodistillation and analyzed by gas chromatography coupled with flame ionization detector and ion trap mass spectrometry. The major compound was fenchone, accounting for, on average, 52.60% in L and 66.20% in F, followed by camphor (13.13% versus 27.08%, in L and F, respectively). F essential oil yields (volume per dry weight) decreased from the beginning to the end of the flowering stage, whereas L yields remained constant during the year. The nine main compounds derived from two different subpathways, A and B. The compounds that belong to the same subpathway showed a similar behavior during the year. The essential oils were tested for their antifungal activity using the paper disk diffusion method. The essential oils tested were effective on the inactivation of Rhizoctonia solani and Fusarium oxysporum and less effective against Aspergillus flavus. Among the single compounds tested, fenchone, limonene, and myrtenal appeared to be the more effective on the inhibition of R. solani growth.

  8. 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

  9. In vitro and in vivo antagonism of pathogenic turfgrass fungi by Streptomyces hygroscopicus strains YCED9 and WYE53.

    PubMed

    Chamberlain, K; Crawford, D L

    1999-07-01

    Disease prevention is a current practice used to minimize fungal diseases of turfgrasses in lawns and golf greens. Prevention is accomplished through fungicide applications, and by periodic thatch removal. During the development of a microbial biodethatch product utilizing the lignocellulose-degrading Streptomyces hygroscopicus strains YCED9 and WYE53, we demonstrated using in vitro plate antagonism bioassays that both strains are antagonists of various turfgrass fungal pathogens. These activities were present when the cultures were growing on thatch, as demonstrated by antifungal antagonism bioassays with culture filtrates. Experiments conducted using a growth chamber demonstrated that a bio-dethatch formulation containing spores of strains YCED9 and WYE53 in a zeolite carrier, provided protection for Kentucky bluegrass seedlings against turfgrass pathogens, including Pythium ultimum, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia homeocarpa, Gaeumannomyces graminis and Microdochium nivale. Results showed that by integrating the use of the S. hygroscopicus YCED9/WYE53 bio-dethatch formulation into routine turf management practices, it should be possible to both minimize thatch build-up while also controlling fungal turfgrass diseases by way of the antifungal biocontrol activity of these strains. This in turn would help control fungal pathogens in turfgrass while minimizing the need for routine chemical fungicide applications.

  10. 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.

  11. 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 μg. The purified lysozyme showed extraordinary activity against plant pathogenic bacteria and fungi. At 10-μg 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 %).

  12. Molecular and Functional Characterization of a Polygalacturonase-Inhibiting Protein from Cynanchum komarovii That Confers Fungal Resistance in Arabidopsis

    PubMed Central

    Liu, Nana; Ma, Xiaowen; Zhou, Sihong; Wang, Ping; Sun, Yun; Li, Xiancai; Hou, Yuxia

    2016-01-01

    Compliance with ethical standards: This study did not involve human participants and animals, and the plant of interest is not an endangered species. Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat proteins that plants produce against polygalacturonase, a key virulence agent in pathogens. In this paper, we cloned and purified CkPGIP1, a gene product from Cynanchum komarovii that effectively inhibits polygalacturonases from Botrytis cinerea and Rhizoctonia solani. We found the expression of CkPGIP1 to be induced in response to salicylic acid, wounding, and infection with B. cinerea and R. solani. In addition, transgenic overexpression in Arabidopsis enhanced resistance against B. cinerea. Furthermore, CkPGIP1 obtained from transgenic Arabidopsis inhibited the activity of B. cinerea and R. solani polygalacturonases by 62.7–66.4% and 56.5–60.2%, respectively. Docking studies indicated that the protein interacts strongly with the B1-sheet at the N-terminus of the B. cinerea polygalacturonase, and with the C-terminus of the polygalacturonase from R. solani. This study highlights the significance of CkPGIP1 in plant disease resistance, and its possible application to manage fungal pathogens. PMID:26752638

  13. Linkage map construction in allotetraploid creeping bentgrass (Agrostis stolonifera L.).

    PubMed

    Chakraborty, N; Bae, J; Warnke, S; Chang, T; Jung, G

    2005-08-01

    Creeping bentgrass (Agrostis stolonifera L.) is one of the most adapted bentgrass species for use on golf course fairways and putting greens because of its high tolerance to low mowing height. It is a highly outcrossing allotetraploid species (2n=4x=28, A(2) and A(3) subgenomes). The first linkage map in this species is reported herein, and it was constructed based on a population derived from a cross between two heterozygous clones using 169 RAPD, 180 AFLP, and 39 heterologous cereal and 36 homologous bentgrass cDNA RFLP markers. The linkage map consists of 424 mapped loci covering 1,110 cM in 14 linkage groups, of which seven pairs of homoeologous chromosomes were identified based on duplicated loci. The numbering of all seven linkage groups in the bentgrass map was assigned according to common markers mapped on syntenous chromosomes of ryegrass and wheat. The number of markers linked in coupling and repulsion phase was in a 1:1 ratio, indicating disomic inheritance. This supports a strict allotetraploid inheritance in creeping bentgrass, as suggested by previous work based on chromosomal pairing and isozymes. This linkage map will assist in the tagging and eventually in marker-assisted breeding of economically important quantitative traits like disease resistance to dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn).

  14. Collagenolytic enzymes produced by fungi: a systematic review.

    PubMed

    Wanderley, Maria Carolina de Albuquerque; Neto, José Manoel Wanderley Duarte; Filho, José Luiz de Lima; Lima, Carolina de Albuquerque; Teixeira, José António Couto; Porto, Ana Lúcia Figueiredo

    Specific proteases capable of degrading native triple helical or denatured collagen have been required for many years and have a large spectrum of applications. There are few complete reports that fully uncover production, characterization and purification of fungi collagenases. In this review, authors searched through four scientific on line data bases using the following keywords (collagenolytic OR collagenase) AND (fungi OR fungus OR fungal) AND (production OR synthesis OR synthesize) AND (characterization). Scientific criteria were adopted in this review to classify found articles by score (from 0 to 10). After exclusion criteria, 21 articles were selected. None obtained the maximum of 10 points defined by the methodology, which indicates a deficiency in studies dealing simultaneously with production, characterization and purification of collagenase by fungi. Among microorganisms studied the non-pathogenic fungi Penicillium aurantiogriseum and Rhizoctonia solani stood out in volumetric and specific collagenase activity. The only article found that made sequencing of a true collagenase showed 100% homology with several metalloproteinases fungi. A clear gap in literature about collagenase production by fungi was verified, which prevents further development in the area and increases the need for further studies, particularly full characterization of fungal collagenases with high specificity to collagen.

  15. Antifungal activity of essential oil and its constituents from Calocedrus macrolepis var. formosana Florin leaf against plant pathogenic fungi.

    PubMed

    Chang, Hui-Ting; Cheng, Ying-Hung; Wu, Chi-Lin; Chang, Shang-Tzen; Chang, Tun-Tschu; Su, Yu-Chang

    2008-09-01

    Resistance to conventional fungicides causes the poor disease control of agriculture. Natural products from plants have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antipathogenic activity of the leaf essential oil and its constituents from Calocedrus macrolepis var. formosana Florin were evaluated in vitro against six plant pathogenic fungi. Chemical analysis of leaf oil by GC/MS allowed identification of alpha-pinene (44.2%), limonene (21.6%), beta-myrcene (8.9%), beta-caryophyllene (8.2%), caryophyllene oxide (2.4%), alpha-cadinol (1.6%), beta-pinene (1.2%), and T-muurolol (1.1%) as main components. Sesquiterpenoid components of the oil were more effective than monoterpenoid components of the oil. In particular, T-muurolol and alpha-cadinol strongly inhibited the growth of Rhizoctonia solani and Fusarium oxysporum, with the IC(50) values < 50 microg ml(-1). These compounds also efficiently inhibited the mycelial growths of Colletotrichum gloeosporioides, P. funerea, Ganoderma australe and F. solani. These results showed that T-muurolol and alpha-cadinol possess antifungal activities against a broad spectrum of tested plant pathogenic fungi and could be used as potential antifungal agents for the control of fungal diseases in plants.

  16. Stacking of antimicrobial genes in potato transgenic plants confers increased resistance to bacterial and fungal pathogens.

    PubMed

    Rivero, Mercedes; Furman, Nicolás; Mencacci, Nicolás; Picca, Pablo; Toum, Laila; Lentz, Ezequiel; Bravo-Almonacid, Fernando; Mentaberry, Alejandro

    2012-01-20

    Solanum tuberosum plants were transformed with three genetic constructions expressing the Nicotiana tabacum AP24 osmotine, Phyllomedusa sauvagii dermaseptin and Gallus gallus lysozyme, and with a double-transgene construction expressing the AP24 and lysozyme sequences. Re-transformation of dermaseptin-transformed plants with the AP24/lysozyme construction allowed selection of plants simultaneously expressing the three transgenes. Potato lines expressing individual transgenes or double- and triple-transgene combinations were assayed for resistance to Erwinia carotovora using whole-plant and tuber infection assays. Resistance levels for both infection tests compared consistently for most potato lines and allowed selection of highly resistant phenotypes. Higher resistance levels were found in lines carrying the dermaseptin and lysozyme sequences, indicating that theses proteins are the major contributors to antibacterial activity. Similar results were obtained in tuber infection tests conducted with Streptomyces scabies. Plant lines showing the higher resistance to bacterial infections were challenged with Phytophthora infestans, Rhizoctonia solani and Fusarium solani. Considerable levels of resistance to each of these pathogens were evidenced employing semi-quantitative tests based in detached-leaf inoculation, fungal growth inhibition and in vitro plant inoculation. On the basis of these results, we propose that stacking of these transgenes is a promising approach to achieve resistance to both bacterial and fungal pathogens.

  17. Effect of Nanohexaconazole on Nitrogen Fixing Blue Green Algae and Bacteria.

    PubMed

    Kumar, Rajesh; Gopal, Madhuban; Pabbi, Sunil; Paul, Sangeeta; Alam, Md Imteyaz; Yadav, Saurabh; Nair, Kishore Kumar; Chauhan, Neetu; Srivastava, Chitra; Gogoi, Robin; Singh, Pradeep Kumar; Goswami, Arunava

    2016-01-01

    Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.

  18. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.)

    PubMed Central

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens. PMID:28056070

  19. Pathogen-induced SGT1 of Arachis diogoi induces cell death and enhanced disease resistance in tobacco and peanut.

    PubMed

    Kumar, Dilip; Kirti, Pulugurtha Bharadwaja

    2015-01-01

    We have identified a transcript derived fragment (TDF) corresponding to SGT1 in a study of differential gene expression on the resistant wild peanut, Arachis diogoi, upon challenge from the late leaf spot pathogen, Phaeoisariopsis personata, and cloned its full-length cDNA followed by subsequent validation through q-PCR. Sodium nitroprusside, salicylic acid, ethephon and methyl jasmonate induced the expression of AdSGT1, while the treatment with abscisic acid did not elicit its up-regulation. AdSGT1 is localized to both nucleus and cytoplasm. Its overexpression induced hypersensitive-like cell death in tobacco under transient conditional expression using the estradiol system, and this conditional expression of AdSGT1 was also associated with the up-regulation of NtHSR203J, HMGR and HIN1, which have been shown to be associated with hypersensitive response in tobacco in earlier studies. Expression of the cDNA in a susceptible cultivated peanut variety enhanced its resistance against the late leaf spot pathogen, Phaeoisariopsis personata, while the heterologous expression in tobacco enhanced its resistance against Phytophthora parasitica var. nicotianae, Alternaria alternata var. nicotianae and Rhizoctonia solani. Constitutive expression in peanut was associated with the co-expression of resistance-related genes, CC-NB-LRR and some protein kinases.

  20. Rhizobia: a potential biocontrol agent for soilborne fungal pathogens.

    PubMed

    Das, Krishnashis; Prasanna, Radha; Saxena, Anil Kumar

    2017-03-12

    Rhizobia are a group of organisms that are well known for their ability to colonize root surfaces and form symbiotic associations with legume plants. They not only play a major role in biological nitrogen fixation but also improve plant growth and reduce disease incidence in various crops. Rhizobia are known to control the growth of many soilborne plant pathogenic fungi belonging to different genera like Fusarium, Rhizoctonia, Sclerotium, and Macrophomina. Antagonistic activity of rhizobia is mainly attributed to production of antibiotics, hydrocyanic acid (HCN), mycolytic enzymes, and siderophore under iron limiting conditions. Rhizobia are also reported to induce systemic resistance and enhance expression of plant defense-related genes, which effectively immunize the plants against pathogens. Seed bacterization with appropriate rhizobial strain leads to elicitation and accumulation of phenolic compounds, isoflavonoid phytoalexins, and activation of enzymes like L-phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), peroxidase (POX), polyphenol oxidase (PPO), and others involved in phenylpropanoid and isoflavonoid pathways. Development of Rhizobium inoculants with dual attributes of nitrogen fixation and antagonism against phytopathogens can contribute to increased plant growth and productivity. This compilation aims to bring together the available information on the biocontrol facet of rhizobia and identify research gaps and effective strategies for future research in this area.

  1. 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.

  2. 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.

  3. 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; Smoliński, 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.

  4. Synthesis, antifungal activity and structure-activity relationships of vanillin oxime-N-O-alkanoates.

    PubMed

    Ahluwalia, Vivek; Garg, Nandini; Kumar, Birendra; Walia, Suresh; Sati, Om P

    2012-12-01

    Vanillin oxime-N-O-alkanoates were synthesized following reaction of vanillin with hydroxylamine hydrochloride, followed by reaction of the resultant oxime with acyl chlorides. The structures of the compounds were confirmed by IR, 1H, 13C NMR and mass spectral data. The test compounds were evaluated for their in vitro antifungal activity against three phytopathogenic fungi Macrophomina phaseolina, Rhizoctonia solani and Sclerotium rolfsii by the poisoned food technique. The moderate antifungal activity of vanillin was slightly increased following its conversion to vanillin oxime, but significantly increased after conversion of the oxime to oxime-N-O-alkanoates. While vanillin oxime-N-O-dodecanoate with an EC50 value 73.1 microg/mL was most active against M. phaseolina, vanillin oxime-N-O-nonanoate with EC50 of value 66.7 microg/mL was most active against R. solani. The activity increased with increases in the acyl chain length and was maximal with an acyl chain length of nine carbons.

  5. Bioprospecting of plant growth promoting psychrotrophic Bacilli from the cold desert of north western Indian Himalayas.

    PubMed

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

    2016-02-01

    The plant growth promoting psychrotrophic Bacilli were investigated from different sites in north western Indian Himalayas. A total of 247 morphotypes were obtained from different soil and water samples and were grouped into 43 clusters based on 16S rDNA-RFLP analysis with three restriction endonucleases. Sequencing of representative isolates has revealed that these 43 Bacilli belonged to different species of 11 genera viz., Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus and Virgibacillus. With an aim to develop microbial inoculants that can perform efficiently at low temperatures, all representative isolates were screened for different plant growth promoting traits at low temperatures (5-15 degrees C). Among the strains, variations were observed for production (%) of indole-3-acetic acid (20), ammonia (19), siderophores (11), gibberellic acid (4) and hydrogen cyanide (2); solubilisation (%) of zinc (14), phosphate (13) and potassium (7); 1-aminocyclopropane-1-carboxylate deaminase activity (6%) and biocontrol activity (4%) against Rhizoctonia solani and Macrophomina phaseolina. Among all the strains, Bacillus licheniformis, Bacillus muralis, Desemzia incerta, Paenibacillus tylopili and Sporosarcina globispora were found to be potent candidates to be developed as inoculants as they exhibited multiple PGP traits at low temperature.

  6. Proteomic and morphometric study of the in vitro interaction between Oncidium sphacelatum Lindl. (Orchidaceae) and Thanatephorus sp. RG26 (Ceratobasidiaceae).

    PubMed

    López-Chávez, Mariana Yadira; Guillén-Navarro, Karina; Bertolini, Vincenzo; Encarnación, Sergio; Hernández-Ortiz, Magdalena; Sánchez-Moreno, Irene; Damon, Anne

    2016-07-01

    Orchidaceae establish symbiotic relationships with fungi in the Rhizoctonia group, resulting in interactions beneficial to both organisms or in cell destruction in one of them (pathogenicity). Previous studies have focused mostly on terrestrial species with a few, preliminary studies, on epiphytes. To further our understanding of the molecular mechanisms involved in these symbioses, we evaluated the interaction between Oncidium sphacelatum Lindl. and the mycorrhizal fungus Thanatephorus sp. strain RG26 (isolated from a different orchid species) in vitro using morphometric and proteomic analyses. Evidence from the morphometric and microscopic analysis showed that the fungus promoted linear growth and differentiation of orchid protocorms during 98 days interaction. On day 63, protocorm development was evident, so we analyzed the physiological response of both organisms at that moment. Proteome results suggest that orchid development stimulated by the fungus apparently involves cell cycle proteins, purine recycling, ribosome biogenesis, energy metabolism, and secretion that were up-regulated in the orchid; whereas in the fungus, a high expression of proteins implicated in stress response, protein-protein interaction, and saccharides and protein biosynthesis were found in the symbiotic interaction. This is the first work reporting proteins differentially expressed in the epiphytic orchid-fungus interaction and will contribute to the search for molecular markers that will facilitate the study of this symbiosis in both wild orchids and those in danger of extinction.

  7. Laccase-catalysed iodide oxidation in presence of methyl syringate.

    PubMed

    Kulys, Juozas; Bratkovskaja, Irina; Vidziunaite, Regina

    2005-10-05

    The kinetics of potassium triiodide (KI(3)) formation during fungal laccase action was investigated in presence of methyl syringate (MS). The recombinant forms of Polyporus pinsitus (rPpL), Myceliophthora thermophila (rMtL), Coprinus cinereus (rCcL), and Rhizoctonia solani (rRsL) laccases were used. The triiodide formation rate reached 6.1, 5.5, 6.0, and 2.1 microM/min at saturated rPpL, rCcL, rRsL, and rMtL concentration, respectively, in acetate buffer solution pH 5.5 and in presence of 10 microM of MS and 1 mM of potassium iodide. The triiodide formation rate increased if pH decreased from 6.5 to 4.5. The scheme of laccase-catalysed iodide oxidation includes stadium of MS interaction with oxidized laccase with concomitant production of MS(ox). The reaction of MS(ox) with iodide produced triiodide. The turnover number of MS was 93 and 44 at pH 5.5 for rPpL and rMtL, respectively. The scheme also contained a stadium of reversible reduction of laccase active centre with the mediator explaining the different saturation rate of triiodide production. The fitting kinetic data revealed that the reversibility of the reaction increased for laccases containing lower redox potential of copper type I.

  8. Biological Control of Soil Pests by Mixed Application of Entomopathogenic and Fungivorous Nematodes

    PubMed Central

    Ishibashi, N.; Choi, D-R.

    1991-01-01

    In greenhouse experiments, massive application of the fungivorous nematode, Aphelenchus avenae, in summer at 26-33 C (1 x l0⁵ nematodes/500 cm³ autoclaved soil) or in autumn at 18-23 C (5 x 10⁴ nematodes/500 cm³ autoclaved soil) suppressed pre-emergence damping-off of cucumber seedlings due to Rhizoctonia solani AG-4 by 67% or 87%, respectively. Application of 2 x l0⁵ A. avenae to sterilized soil infested with R. solani caused leafminer-like symptom on the cotyledons, which did not occur in mixed inoculations with the entomopathogenic nematode, Steinernema carpocapsae. When 1 x 10⁶ A. avenae were applied 3 days before inoculation with 100 Meloidogyne incognita juveniles, gall numbers on tomato roots were reduced to 50% of controls. Gall numbers also were suppressed by S. carpocapsae (str. All). Reduction in gall numbers was no greater with mixed application of A. avenae and S. carpocapsae than with application of single species, even though twice the number of nematodes were added in the former case. These nematodes were positively attracted to tomato root tips. Aphelenchus avenae suppressed infection of the turnip moth, Agrotis segetum, but not the common cutworm, Spodoptera litura, by S. carpocapsae. PMID:19283109

  9. Toxicity of zinc to fungi, bacteria, and coliphages: influence of chloride ions.

    PubMed Central

    Babich, H; Stotzky, G

    1978-01-01

    A 10 mM concentration of Zn2+ decreased the survival of Escherichia coli; enhanced the survival of Bacillus cereus; did not significantly affect the survival of Pseudomonas aeruginosa, Norcardia corallina, and T1, T7, P1, and phi80 coliphages; completely inhibited mycelial growth of Rhizoctonia solani; and reduced mycelial growth of Fusarium solani, Cunninghamella echinulata, Aspergillus niger, and Trichoderma viride. The toxicity of zinc to the fungi, bacteria, and coliphages was unaffected, lessened, or increased by the addition of high concentrations of NaCl. The increased toxicity of zinc in the presence of high concentrations of NaCl was not a result of a synergistic interaction between Zn2+ and elevated osmotic pressures but of the formation of complex anionic ZnCl species that exerted greater toxicities than did cationic Zn2+. Conversely, the decrease in zinc toxicity with increasing concentrations of NaCl probably reflected the decrease in the levels of Zn2+ due to the formation of Zn-Cl species, which was less inhibitory to these microbes than was Zn2+. A. niger tolerated higher concentrations of zinc in the presence of NaCl at 37 than at 25 degrees C. PMID:736544

  10. Resistance to Multiple Tuber Diseases Expressed in Somaclonal Variants of the Potato Cultivar Russet Burbank

    PubMed Central

    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

  11. Fine-scale spatial distribution of orchid mycorrhizal fungi in the soil of host-rich grasslands.

    PubMed

    Voyron, Samuele; Ercole, Enrico; Ghignone, Stefano; Perotto, Silvia; Girlanda, Mariangela

    2017-02-01

    Mycorrhizal fungi are essential for the survival of orchid seedlings under natural conditions. The distribution of these fungi in soil can constrain the establishment and resulting spatial arrangement of orchids at the local scale, but the actual extent of occurrence and spatial patterns of orchid mycorrhizal (OrM) fungi in soil remain largely unknown. We addressed the fine-scale spatial distribution of OrM fungi in two orchid-rich Mediterranean grasslands by means of high-throughput sequencing of fungal ITS2 amplicons, obtained from soil samples collected either directly beneath or at a distance from adult Anacamptis morio and Ophrys sphegodes plants. Like ectomycorrhizal and arbuscular mycobionts, OrM fungi (tulasnelloid, ceratobasidioid, sebacinoid and pezizoid fungi) exhibited significant horizontal spatial autocorrelation in soil. However, OrM fungal read numbers did not correlate with distance from adult orchid plants, and several of these fungi were extremely sporadic or undetected even in the soil samples containing the orchid roots. Orchid mycorrhizal 'rhizoctonias' are commonly regarded as unspecialized saprotrophs. The sporadic occurrence of mycobionts of grassland orchids in host-rich stands questions the view of these mycorrhizal fungi as capable of sustained growth in soil.

  12. Evaluation of the Biocontrol Potential of Purpureocillium lilacinum QLP12 against Verticillium dahliae in Eggplant

    PubMed Central

    Zhang, Jing; Zong, Zhaofeng

    2017-01-01

    A fungus with broad spectrum antifungal activity was isolated from the soil in Qinling Mountain, Shaanxi Province, in China. The fungus was identified as Purpureocillium lilacinum based on ITS rDNA gene analysis. The strain, coded as QLP12, showed high inhibition activity on fungal mycelium growth in vitro, especially to Mucor piriformis, Trichothecium roseum, Rhizoctonia solani, and Verticillium dahliae, and its potential for biocontrol efficacy of eggplant. Verticillium wilt disease caused by Verticillium dahliae among 10 fungal species tested was explored. In greenhouse experiments, QLP12 showed an excellent growth-promoting effect on eggplant seed germination (76.7%), bud growth (79.4%), chlorophyll content (47.83%), root activity (182.02%), and so on. QLP12 can colonize the eggplant interior and also develop in rhizosphere soil. In greenhouse, the incidence of Verticillium wilt decreased by 83.82% with pretreated QLP12 fermentation broth in the soil. In the field, QLP12 showed prominent biocontrol effects on Verticillium wilt by reducing the disease index over the whole growth period, a decline of 40.1%. This study showed that the strain QLP12 is not only an effective biocontrol agent for controlling Verticillium wilt of eggplant, but also a plant growth-promoting fungus that deserves to be further developed. PMID:28303252

  13. Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics.

    PubMed

    Calvo, Pamela; Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza; Zúñiga, Doris

    2010-10-01

    Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promising PGP strains. In this study, sixty three Bacillus strains isolated from the rhizosphere of native potato varieties growing in the Andean highlands of Peru were screened for in vitro antagonism against Rhizoctonia solani and Fusarium solani. A high prevalence (68%) of antagonists against R. solani was found. Ninety one percent of those strains also inhibited the growth of F. solani. The antagonistic strains were also tested for other plant growth promotion activities. Eighty one percent produced some level of the auxin indole-3-acetic acid, and 58% solubilized tricalcium phosphate. Phylogenetic analysis revealed that the majority of the strains belonged to the B. amyloliquefaciens species, while strains Bac17M11, Bac20M1 and Bac20M2 may correspond to a putative new Bacillus species. The results suggested that the rhizosphere of native potatoes growing in their natural habitat in the Andes is a rich source of Bacillus fungal antagonists, which have a potential to be used in the future as PGP inoculants to improve potato crop.

  14. Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics

    PubMed Central

    Calvo, Pamela; Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza; Zúñiga, Doris

    2010-01-01

    Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promising PGP strains. In this study, sixty three Bacillus strains isolated from the rhizosphere of native potato varieties growing in the Andean highlands of Peru were screened for in vitro antagonism against Rhizoctonia solani and Fusarium solani. A high prevalence (68%) of antagonists against R. solani was found. Ninety one percent of those strains also inhibited the growth of F. solani. The antagonistic strains were also tested for other plant growth promotion activities. Eighty one percent produced some level of the auxin indole-3-acetic acid, and 58% solubilized tricalcium phosphate. Phylogenetic analysis revealed that the majority of the strains belonged to the B. amyloliquefaciens species, while strains Bac17M11, Bac20M1 and Bac20M2 may correspond to a putative new Bacillus species. The results suggested that the rhizosphere of native potatoes growing in their natural habitat in the Andes is a rich source of Bacillus fungal antagonists, which have a potential to be used in the future as PGP inoculants to improve potato crop. PMID:24031569

  15. 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.

  16. Antifungal activity of metabolites of the endophytic fungus Trichoderma brevicompactum from garlic

    PubMed Central

    Shentu, Xuping; Zhan, Xiaohuan; Ma, Zheng; Yu, Xiaoping; Zhang, Chuanxi

    2014-01-01

    The endophytic fungus strain 0248, isolated from garlic, was identified as Trichoderma brevicompactum based on morphological characteristics and the nucleotide sequences of ITS1-5.8S- ITS2 and tef1. The bioactive compound T2 was isolated from the culture extracts of this fungus by bioactivity-guided fractionation and identified as 4β-acetoxy-12,13- epoxy-Δ9-trichothecene (trichodermin) by spectral analysis and mass spectrometry. Trichodermin has a marked inhibitory activity on Rhizoctonia solani, with an EC50 of 0.25 μgmL−1. Strong inhibition by trichodermin was also found for Botrytis cinerea, with an EC50 of 2.02 μgmL−1. However, a relatively poor inhibitory effect was observed for trichodermin against Colletotrichum lindemuthianum (EC50 = 25.60 μgmL−1). Compared with the positive control Carbendazim, trichodermin showed a strong antifungal activity on the above phytopathogens. There is little known about endophytes from garlic. This paper studied in detail the identification of endophytic T. brevicompactum from garlic and the characterization of its active metabolite trichodermin. PMID:24948941

  17. New production process of the antifungal chaetoglobosin A using cornstalks.

    PubMed

    Jiang, Cheng; Song, Jinzhu; Zhang, Junzheng; Yang, Qian

    2017-02-04

    Chaetoglobosin A is an antibacterial compound produced by Chaetomium globosum, with potential application as a biopesticide and cancer treatment drug. The aim of this study was to evaluate the feasibility of utilizing cornstalks to produce chaetoglobosin A by C. globosum W7 in solid-batch fermentation and to determine an optimal method for purification of the products. The output of chaetoglobosin A from the cornstalks was 0.34mg/g, and its content in the crude extract was 4.80%. Purification conditions were optimized to increase the content of chaetoglobosin A in the crude extract, including the extract solvent, temperature, and pH value. The optimum process conditions were found to be acetone as the extractant, under room temperature, and at a pH value of 13. Under these conditions, a production process of the antifungal chaetoglobosin A was established, and the content reached 19.17%. Through further verification, cornstalks could replace crops for the production of chaetoglobosin A using this new production process. Moreover, the purified products showed great inhibition against Rhizoctonia solani, with chaetoglobosin A confirmed as the main effective constituent (IC50=3.88μg/mL). Collectively, these results demonstrate the feasibility of using cornstalks to synthesize chaetoglobosin A and that the production process established in this study was effective.

  18. 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.

  19. Detection and assessment of chemical hormesis on the radial growth in vitro of oomycetes and fungal plant pathogens.

    PubMed

    Flores, Francisco J; Garzon, Carla D

    2012-01-01

    Although plant diseases can be caused by bacteria, viruses, and protists, most are caused by fungi and fungus-like oomycetes. Intensive use of fungicides with the same mode of action can lead to selection of resistant strains increasing the risk of unmanageable epidemics. In spite of the integrated use of nonchemical plant disease management strategies, agricultural productivity relies heavily on the use of chemical pesticides and biocides for disease prevention and treatment and sanitation of tools and substrates. Despite the prominent use of fungi in early hormesis studies and the continuous use of yeast as a research model, the relevance of hormesis in agricultural systems has not been investigated by plant pathologists, until recently. A protocol was standardized for detection and assessment of chemical hormesis in fungi and oomycetes using radial growth as endpoint. Biphasic dose-responses were observed in Pythium aphanidermatum exposed to sub-inhibitory doses of ethanol, cyazofamid, and propamocarb, and in Rhizoctonia zeae exposed to ethanol. This report provides an update on chemical hormesis in fungal plant pathogens and a perspective on the potential risks it poses to crop productivity and global food supply.

  20. Potential of a novel antibiotic, 2-methylheptyl isonicotinate, as a biocontrol agent against fusarial wilt of crucifers.

    PubMed

    Bordoloi, Gojen N; Kumari, Babita; Guha, Arijit; Thakur, Debajit; Bordoloi, Manabjyoti; Roy, Monoj K; Bora, Tarun C

    2002-03-01

    Screening for newer bioactive compounds from microbial metabolites resulted in the isolation of a novel antibiotic from the culture filtrate, Streptomyces sp 201, of a soil. The bioactive compound, with antifungal and antibacterial activity, was identified as 2-methylheptyl isonicotinate. The antifungal activity of live culture, culture broth and the isolated bioactive compound showed marked inhibition against dominant soil-borne phytopathogens such as Fusarium oxysporum Schlect, F moniliforme Sheldon, F semitectum Berkeley & Ravenel, F solani (Martius) Sacc and Rhizoctonia solani Kuehn. The compound had no effect on seed germination and seedling development as displayed by root and stem growth of the test plant species. In pot experiments with seedlings of cruciferous plants such as Raphanus sativus L (radish), Brassica campestris L (yellow mustard), Brassica oleracea var botrytis L (cauliflower), the antibiotic compound showed promising protective activity of 92% when seeds of the test plants were treated at a dose of 50 micrograms ml-1 prior to sowing. Seed treatment with a spore suspension (3 x 10(8) spores ml-1) of the Streptomyces sp 201 displayed protective activity in the range of 56-60%. Seeds coated with 2.5% methyl cellulose-amended spores of the antagonist showed protective activity in the range of 64-72%. Further, seed treatment with the culture filtrate of the antagonist also showed promising protective activity in the range of 64-84%.

  1. Humus bacteria of Norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity.

    PubMed

    Elo; Maunuksela; Salkinoja-Salonen; Smolander; Haahtela

    2000-02-01

    We studied the potential of the humus layer of the Norway spruce stands to supply beneficial rhizobacteria to birch (Betula pendula), alder (Alnus incana) and fescue grass (Festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. Axenically grown seedlings of these species were inoculated with the acid spruce humus, pH 3.7-5.3. Actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed plots, whereas plots with nitrogen fertilization contained almost none (Rhizoctonia sp., Botrytis cinerea and Fusarium culmorum. The antagonistic isolates also commonly produced siderophores and/or cell wall degrading enzymes.

  2. Gastrodia anti-fungal protein from the orchid Gastrodia elata confers disease resistance to root pathogens in transgenic tobacco.

    PubMed

    Cox, K D; Layne, D R; Scorza, R; Schnabel, G

    2006-11-01

    Diseases of agricultural crops are caused by pathogens from several higher-order phylogenetic lineages including fungi, straminipila, eubacteria, and metazoa. These pathogens are commonly managed with pesticides due to the lack of broad-spectrum host resistance. Gastrodia anti-fungal protein (GAFP; gastrodianin) may provide a level of broad-spectrum resistance due to its documented anti-fungal activity in vitro and structural similarity to insecticidal lectins. We transformed tobacco (Nicotiana tabacum cv. Wisconsin 38) with GAFP-1 and challenged transformants with agriculturally important plant pathogens from several higher-order lineages including Rhizoctonia solani (fungus), Phytophthora nicotianae (straminipile), Ralstonia solanacearum (eubacterium), and Meloidogyne incognita (metazoan). Quantitative real-time PCR and western blotting analysis indicated that GAFP-1 was transcribed and translated in transgenic lines. When challenged by R. solani and P. nicotianae, GAFP-1 expressing lines had reduced symptom development and improved plant vigor compared to non-transformed and empty vector control lines. These lines also exhibited reduced root galling when challenged by M. incognita. Against R. solanacearum expression of GAFP-1 neither conferred resistance, nor exacerbated disease development. These results indicate that heterologous expression of GAFP-1 can confer enhanced resistance to a diverse set of plant pathogens and may be a good candidate gene for the development of transgenic, root-disease-resistant crops.

  3. 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.

  4. Preparation of Ag/SiO2 nanocomposite and assessment of its antifungal effect on soybean plant (a Vietnamese species DT-26)

    NASA Astrophysics Data System (ADS)

    Chau Nguyen, Hoai; Thuy Nguyen, Thi; Hien Dao, Trong; Buu Ngo, Quoc; Pham, Hoang Long; Nguyen, Thi Bich Ngoc

    2016-12-01

    Soybean crop losses due to fungal diseases are considerable and directly depend on the severity of the disease. The objective of this study was to assess antifungal activity of silver/silica (Ag/SiO2) nanocomposite against crop pathogenic fungi (Fusarium oxysporium and Rhizoctonia solani) in soybean farming. Firstly, silica particles with a size ranging from 20 to 30 nm were modified with 3-aminopropyl triethoxysilane (APTES) for 2 h. Then these amino acid - functionalized silica particles were exposed to silver ion solution followed by reduction of silver ions with sodium borohydride to form Ag/SiO2 nanocomposite. The formation of the linkage between APTES and silica particles was confirmed by Fourier transform infrared (FTIR) spectroscopy. The surface plasmon absorption maximum at 400 nm confirmed the nano essence of the silver particles on silica particles. For the seed coating, bentonite from Lam Dong deposit, Vietnam, was used as an encapsulation substance, while carboxymethyl cellulose (CMC) was used as a binding agent. The assessment of fungicidal activity of the Ag/SiO2 nanocomposite produced showed that this product is effective in inhibition of the pathogenic fungi in soybean plant.

  5. Effect of Compost on Rhizosphere Microflora of the Tomato and on the Incidence of Plant Growth-Promoting Rhizobacteria

    PubMed Central

    de Brito, Alvarez M. A.; Gagne, S.; Antoun, H.

    1995-01-01

    Four commercial composts were added to soil to study their effect on plant growth, total rhizosphere microflora, and incidence of plant growth-promoting rhizobacteria (PGPR) in the rhizosphere of tomato plants. Three of the compost treatments significantly improved plant growth, while one compost treatment significantly depressed it. Compost amendments caused only small variations in the total numbers of bacteria, actinomycetes, and fungi in the rhizosphere of tomato plants. A total of 709 bacteria were isolated from the four compost treatments and the soil control to determine the percentage of PGPR in each treatment. The PGPR tests measured antagonism to soilborne root pathogens, production of indoleacetic acid, cyanide, and siderophores, phosphate solubilization, and intrinsic resistance to antibiotics. Our results show that the addition of some composts to soil increased the incidence in the tomato rhizosphere of bacteria exhibiting antagonism towards Fusarium oxysporum f. sp. radicis-lycopersici, Pyrenochaeta lycopersici, Pythium ultimum, and Rhizoctonia solani. The antagonistic effects observed were associated with marked increases in the percentage of siderophore producers. No significant differences were observed in the percentage of cyanogens, whereas the percentages of phosphate solubilizers and indoleacetic acid producers were affected, respectively, by one and two compost treatments. Intrinsic resistance to antibiotics was only marginally different among the rhizobacterial populations. Our results suggest that compost may stimulate the proliferation of antagonists in the rhizosphere and confirm previous reports indicating that the use of composts in container media has the potential to protect plants from soilborne root pathogens. PMID:16534902

  6. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.).

    PubMed

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens.

  7. 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

  8. 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.

  9. The Transcription Factor OsWRKY45 Negatively Modulates the Resistance of Rice to the Brown Planthopper Nilaparvata lugens.

    PubMed

    Huangfu, Jiayi; Li, Jiancai; Li, Ran; Ye, Meng; Kuai, Peng; Zhang, Tongfang; Lou, Yonggen

    2016-05-31

    WRKY transcription factors play a central role not only in plant growth and development but also in plant stress responses. However, the role of WRKY transcription factors in herbivore-induced plant defenses and their underlying mechanisms, especially in rice, remains largely unclear. Here, we cloned a rice WRKY gene OsWRKY45, whose expression was induced by mechanical wounding, by infestation of the brown planthopper (BPH, Nilaparvata lugens) and by treatment with jasmonic acid (JA) or salicylic acid (SA). The antisense expression of OsWRKY45 (as-wrky) enhanced BPH-induced levels of H₂O₂ and ethylene, reduced feeding and oviposition preference as well as the survival rate of BPH, and delayed the development of BPH nymphs. Consistently, lower population densities of BPH on as-wrky lines, compared to those on wild-type (WT) plants, were observed in field experiments. On the other hand, as-wrky lines in the field had lower susceptibility to sheath blight (caused by Rhizoctonia solani) but higher susceptibility to rice blast (caused by Magnaporthe oryzae) than did WT plants. These findings suggest that OsWRKY45 plays important but contrasting roles in regulating the resistance of rice to pathogens and herbivores, and attention should be paid if OsWRKY45 is used to develop disease or herbivore-resistant rice.

  10. 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 β 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.

  11. 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.

  12. Evaluation of the Biocontrol Potential of Purpureocillium lilacinum QLP12 against Verticillium dahliae in Eggplant.

    PubMed

    Lan, Xingjie; Zhang, Jing; Zong, Zhaofeng; Ma, Qing; Wang, Yang

    2017-01-01

    A fungus with broad spectrum antifungal activity was isolated from the soil in Qinling Mountain, Shaanxi Province, in China. The fungus was identified as Purpureocillium lilacinum based on ITS rDNA gene analysis. The strain, coded as QLP12, showed high inhibition activity on fungal mycelium growth in vitro, especially to Mucor piriformis, Trichothecium roseum, Rhizoctonia solani, and Verticillium dahliae, and its potential for biocontrol efficacy of eggplant. Verticillium wilt disease caused by Verticillium dahliae among 10 fungal species tested was explored. In greenhouse experiments, QLP12 showed an excellent growth-promoting effect on eggplant seed germination (76.7%), bud growth (79.4%), chlorophyll content (47.83%), root activity (182.02%), and so on. QLP12 can colonize the eggplant interior and also develop in rhizosphere soil. In greenhouse, the incidence of Verticillium wilt decreased by 83.82% with pretreated QLP12 fermentation broth in the soil. In the field, QLP12 showed prominent biocontrol effects on Verticillium wilt by reducing the disease index over the whole growth period, a decline of 40.1%. This study showed that the strain QLP12 is not only an effective biocontrol agent for controlling Verticillium wilt of eggplant, but also a plant growth-promoting fungus that deserves to be further developed.

  13. 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.

  14. Effect of three organophosphorous nematicides on non-target nematodes and soil microbial community.

    PubMed

    Wada, Satoko; Toyota, Koki

    2008-01-01

    The toxicity of three organophosphorous nematicides, imicyafos, fosthiazate and cadusafos, to non-target organisms in soil was evaluated. Imicyafos and fosthiazate had no significant inhibitory effect on the growth of fungal (Fusarium oxysporum f. sp. lactucae, Rhizoctonia solani and Trichoderma viride) and bacterial (Ralstonia solanacearum and Pseudomonas fluorescens) strains in media at 12.5 to 200 mg L(-1). Cadusafos, however, significantly inhibited the growth of all these strains except R. solanacearum. A pot test was conducted using a soil naturally infested with Pratylenchus penetrans, and treated with imicyafos or fosthiazate, which are less toxic to non-target organisms. The density of P. penetrans decreased to less than 10% of the control level after exposure to imicyafos and fosthiazate at 3 kg active ingredient ha(-1), the conventional dose. No significant effect was observed on the density of free-living nematodes, cellulose decomposition activity, microbial biomass evaluated with the ATP method and number of ammonia oxidizers between the soil treated with imicyafos or fosthiazate and the untreated control soil. Our results revealed that imicyafos and fosthiazate effectively suppressed a plant-parasitic nematode, P. penetrans, but had little impact on free-living nematodes and the soil microbial community.

  15. Involvement of Trichoderma Trichothecenes in the Biocontrol Activity and Induction of Plant Defense-Related Genes

    PubMed Central

    Malmierca, M. G.; Cardoza, R. E.; Alexander, N. J.; McCormick, S. P.; Hermosa, R.; Monte, E.

    2012-01-01

    Trichoderma species produce trichothecenes, most notably trichodermin and harzianum A (HA), by a biosynthetic pathway in which several of the involved proteins have significant differences in functionality compared to their Fusarium orthologues. In addition, the genes encoding these proteins show a genomic organization differing from that of the Fusarium tri clusters. Here we describe the isolation of Trichoderma arundinaceum IBT 40837 transformants which have a disrupted or silenced tri4 gene, a gene encoding a cytochrome P450 monooxygenase that oxygenates trichodiene to give rise to isotrichodiol, and the effect of tri4 gene disruption and silencing on the expression of other tri genes. Our results indicate that the tri4 gene disruption resulted in a reduced antifungal activity against Botrytis cinerea and Rhizoctonia solani and also in a reduced ability to induce the expression of tomato plant defense-related genes belonging to the salicylic acid (SA) and jasmonate (JA) pathways against B. cinerea, in comparison to the wild-type strain, indicating that HA plays an important function in the sensitization of Trichoderma-pretreated plants against this fungal pathogen. Additionally, the effect of the interaction of T. arundinaceum with B. cinerea or R. solani and with tomato seedlings on the expressions of the tri genes was studied. PMID:22562989

  16. Complete genome sequences of the Serratia plymuthica strains 3Rp8 and 3Re4-18, two rhizosphere bacteria with antagonistic activity towards fungal phytopathogens and plant growth promoting abilities.

    PubMed

    Adam, Eveline; Müller, Henry; Erlacher, Armin; Berg, Gabriele

    2016-01-01

    The Serratia plymuthica strains 3Rp8 and 3Re4-18 are motile, Gram-negative, non-sporulating bacteria. Strain 3Rp8 was isolated from the rhizosphere of Brassica napus L. and strain 3Re4-18 from the endorhiza of Solanum tuberosum L. Studies have shown in vitro activity against the soil-borne fungi Verticillium dahliae Kleb., Rhizoctonia solani Kühn, and Sclerotinia sclerotiorum. Here, we announce and describe the complete genome sequence of S. plymuthica 3Rp8 consisting of a single circular chromosome of 5.5 Mb that encodes 4954 protein-coding and 108 RNA-only encoding genes and of S. plymuthica 3Re4-18 consisting of a single circular chromosome of 5.4 Mb that encodes 4845 protein-coding and 109 RNA-only encoding genes. The whole genome sequences and annotations are available in NCBI under the locus numbers CP012096 and CP012097, respectively. The genome analyses revealed genes putatively responsible for the promising plant growth promoting and biocontrol properties including predicting factors such as secretion systems, iron scavenging siderophores, chitinases, secreted proteases, glucanases and non-ribosomal peptide synthetases, as well as unique genomic islands.

  17. Resistance to Multiple Soil-Borne Pathogens of the Pacific Northwest, USA Is Colocated in a Wheat Recombinant Inbred Line Population

    PubMed Central

    Thompson, Alison L.; Mahoney, Aaron K.; Smiley, Richard W.; Paulitz, Timothy C.; Hulbert, Scot; Garland-Campbell, Kim

    2017-01-01

    Soil-borne pathogens of the Pacific Northwest decrease yields in both spring and winter wheat. Pathogens of economic importance include Fusarium culmorum, Pratylenchus neglectus, P. thornei, and Rhizoctonia solani AG8. Few options are available to growers to manage these pathogens and reduce yield loss, therefore the focus for breeding programs is on developing resistant wheat cultivars. A recombinant inbred line population, LouAu (MP-7, NSL 511036), was developed to identify quantitative trait loci (QTL) associated with resistance to P. neglectus and P. thornei. This same population was later suspected to be resistant to F. culmorum and R. solani AG8. This study confirms partial resistance to F. culmorum and R. solani AG8 is present in this population. Six major and 16 speculative QTL were identified across seven measured traits. Four of the six major QTL were found within the same genomic region of the 5A wheat chromosome suggesting shared gene(s) contribute to the resistance. These QTL will be useful in breeding programs looking to incorporate resistance to soil-borne pathogens in wheat cultivars. PMID:28159864

  18. 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.

  19. Antimicrobial activity of globulol isolated from the fruits of Eucalyptus globulus Labill.

    PubMed

    Tan, Manliang; Zhou, Ligang; Huang, Yongfu; Wang, Ye; Hao, Xiaojiang; Wang, Jingguo

    2008-05-10

    An antimicrobial sesquiterpene was separated by bioassay-guided isolation from the petroleum ether fraction of the ethanol crude extract of Eucalyptus globulus Labill (Myrtaceae) fruits, and was identified as globulol by physicochemical properties and spectroscopic analysis. Mycelial growth method revealed that the median effective inhibitory concentration (IC50) values of globulol on Alternaria solani, Fusarium oxysporum f.sp. niverum, F. graminearum, Rhizoctonia solani and Venturia pirina were 47.1 microg mL(-1), 114.3 microg mL(-1), 53.4 microg mL(-1), 56.9 microg mL(-1), 32.1 microg mL(-1) and 21.8 microg mL(-1), respectively. MTT-colorimetric assay revealed that IC50 values of globulol on Xanthomonas vesicatoria and Bacillus subtilis were 158.0 microg mL(-1) and 737.2 microg mL(-1), respectively. The results indicated that globulol could be a main antimicrobial compound in the ethanol crude extract of E. globulus fruits.

  20. Isolation, purification, and characterization of a stable defensin-like antifungal peptide from Trigonella foenum-graecum (fenugreek) seeds.

    PubMed

    Oddepally, R; Guruprasad, L

    2015-03-01

    A novel defensin-like antifungal peptide (Tf-AFP) with molecular mass of 10.3 kDa was isolated from seeds of Trigonella foenum-graecum (fenugreek) by ammonium sulfate precipitation, cation-exchange, gel-filtration, hydrophobic chromatography, and RP-HPLC. Mass spectroscopic analysis revealed the intact mass of the purified antifungal peptide as 10321.5 Da and high similarity to plant defensins and other antifungal proteins in database search. 2D-PAGE showed pI value to be 8.8 and absence of isoforms. Isolated Tf-AFP inhibited growth of fungal species such as Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani. The antifungal activity was inhibited in the presence of 50 mM NaCl. Circular dichroism analysis demonstrated that the protein is rich in β-sheet structure and highly stable over a wide range of temperatures. Surprisingly, reduction of disulfide bridges and chemical denaturation did not produce large changes in secondary structure as judged by circular dichroism as well as by fluorescence spectroscopy.