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Spore Suspension (spore + suspension)
Selected AbstractsEffect of inoculum type and timing of application of Coniothyrium minitans on Sclerotinia sclerotiorum: control of sclerotinia disease in glasshouse lettucePLANT PATHOLOGY, Issue 5 2004E. E. Jones The effects of Coniothyrium minitans inoculum quality and an 8-week interval between inoculum application and crop planting on sclerotinia (Sclerotinia sclerotiorum) disease in three successive lettuce crops were investigated in a glasshouse trial. Spore suspensions of three isolates of C. minitans (Conio, IVT1 and Contans) applied at 108 CFU m,2 and a standard Conio maizemeal,perlite application (06 L m,2, 1011 CFU m,2) were assessed for their ability to control S. sclerotiorum. Only the maizemeal,perlite inoculum (isolate Conio) consistently reduced sclerotinia disease. In the third lettuce crop only, isolates IVT1 and Contans formulated by Prophyta and isolate IVT as an oil,water formulation, all applied as spore suspensions, reduced disease at harvest compared with the untreated control. Recovery, viability and C. minitans infection of sclerotia buried during the 8-week period prior to each of the three lettuce crops, and of sclerotia formed on the crop, were tested. Only the maizemeal,perlite inoculum (isolate Conio) reduced the recovery of sclerotia buried in soil for weeks between inoculum application and crop planting, reducing their viability and increasing infection by C. minitans. Eight weeks was sufficient to enable C. minitans to infect sclerotia of S. sclerotiorum, and may account for disease control. After harvest of the second and third crops, maizemeal,perlite treatment (isolate Conio) reduced the number and viability of sclerotia recovered on the soil surface and increased infection by C. minitans compared with spore-suspension treatments. The effect of inoculum concentration and the influence of soil temperature (varying with time of year) on infection of sclerotia by C. minitans are discussed. [source] The formation of spores in biofilms of Anoxybacillus flavithermusJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2009S.A. Burgess Abstract Aims:, To examine the rate and the extent of spore formation in Anoxybacillus flavithermus biofilms and to test the effect of one key variable , temperature , on spore formation. Methods and Results:, A continuous flow laboratory reactor was used to grow biofilms of the typical dairy thermophile A. flavithermus (strain CM) in skim milk. The reactor was inoculated with either a washed culture or a spore suspension of A. flavithermus CM, and was run over an 8·5 h period at three different temperatures of 48, 55 and 60°C. Change in impedance was used to determine the cell numbers in the milk and on the surface of the stainless steel reactor tubes. The biofilm developed at all three temperatures within 6,8 h. Spores formed at 55 and 60°C and amounted to approx. 10,50% of the biofilm. No spores formed at 48°C. Conclusions:, The results suggest that both biofilm formation and spore formation of A. flavithermus can occur very rapidly and simultaneously. In addition, temperature variation has a considerable effect on the formation of spores. Significance and Impact of the Study:, This information will provide direction for developing improved ways in which to manipulate conditions in milk powder manufacturing plants to control biofilms and spores of A. flavithermus. [source] In vitro Selection for Fusarium Wilt Resistance in GladiolusJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2008Idrees Ahmad Nasir Abstract Cormels pieces of four Fusarium susceptible Gladiolus cultivars (Friendship, Peter Pears, Victor Borge and Novalux) formed friable calli when cultured in vitro on Murashige and Skoog basal medium containing various concentrations of auxin and cytokinin. The friable calli established cell suspensions. Plantlet regeneration was obtained from the control callus, control cell suspension derived callus and in vitro selected Fusarium oxysporum Schlecht. resistant cell-lines of Friendship. The in vitro cormlets showed 85,95% germination after breaking dormancy of 8 weeks at 4 °C. Cell suspensions of all four Gladiolus cultivars were found to be highly sensitive to fusaric acid. Gradual increase in fusaric acid concentrations to the cell-suspension cultures decreased cell growth considerably. One albino plant was found from the second generation of the in vitro selected cell line of Friendship. The albino plant was found to be highly susceptible to F. oxysporum. The cormlets of all in vitro selected cell lines of Friendship were inoculated with a conidial suspension of the F. oxysporum before planting and were also sprayed with the same spore suspension for further characterization when the height of plants was about 6 cm. The four selected cell lines showed the same response whether or not they were inoculated with conidia of the F. oxysporum. Plantlets of all of the selected cell lines exhibited significant growth as compared with the control after application of conidia of the F. oxysporum. [source] Biochemical Changes in Leaf Tissues of Taro [Colocasia esculenta L. (Schott)] Infected with Phytophthora colocasiaeJOURNAL OF PHYTOPATHOLOGY, Issue 3 2010Manas Ranjan Sahoo Abstract The changes in some biochemical parameters due to Phytophthora leaf blight infection were assessed in leaf tissues of one resistant (DP-25), two moderately resistant (Duradim and Jhankri) and one susceptible (N-118) genotypes of taro [Colocasia esculenta (L.) Schott]. Phytophthora spore suspension (15 000 spore/ml water) was sprayed onto the in vitro raised taro plantlets at 30 days after establishment in pots to induce disease. In comparison with the uninoculated leaves, blight infected leaves showed reduction in protein content and activity of nitrate reductase and increase in total soluble sugar, reducing sugar content and activities of acid phosphatase and alkaline phosphatase among the studied genotypes. Changes in biochemical parameters under induced blight stress as compared with uninoculated control were less in resistant genotypes than that in susceptible genotype. The deviations in biochemical contents were highest in susceptible genotype N-118. Based on the variations of above parameters under stress and non-stress control among the four tested genotypes, the overall pattern of changes was N-118 > Duradim > Jhankri > DP-25, which is in accordance with the pattern of increasing resistance. The resistant genotypes could be used for commercial cultivation and genetic improvement programme to develop resistant varieties to Phytophthora leaf blight disease. [source] Pathogenicity of Phaeoacremonium Species on GrapevinesJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2009Angeles Aroca Abstract Several Phaeoacremonium species have been recently described to include some species involved in disease of decline of woody plants and others associated with human infections. Thirteen species are currently reported on grapevines and they are suspected to be involved in Esca and Petri disease. The pathogenic character of new defined species is still unknown and, therefore, pathogenicity studies were conducted in this work. The pathogenicity of the following species was studied on grapevine seedlings and cuttings: Phaeoacremonium aleophilum, P. angustius, P. inflatipes, P. krajdenii, P. mortoniae, P. parasiticum, P. scolyti, P. venezuelense, P. viticola, and Phaeomoniella chlamydospora included as positive control. Two-month-old grapevine seedlings of Vitis vinifera cv. Malvar and cv. Airen were inoculated by watering 10 individual pots with a spore suspension (107 spores/ml) of each Phaeoacremonium species. All inoculated seedlings showed typical symptoms of a vascular disease 2 months after inoculation. Grapevine cuttings of Vitis vinifera cv. Monastrell were vacuum-inoculated with a spore suspension (108 spores/ml) and individually planted. Plants rated after 5 months showed that all Phaeoacremonium species and P. chlamydospora (used as positive control) caused a significant vascular discoloration, while only Phaeomoniella chlamydospora, Phaoeacremonium mortoniae and P. aleophilum caused a significant root weight reduction compared with a non-inoculated control. Phaoeacremonium parasiticum, P. angustius, P. inflatipes and P. venezuelense caused significant foliar symptoms that included interveinal chlorosis and stunted leaves. [source] Increased effectiveness of the Trichoderma harzianum isolate T-78 against Fusarium wilt on melon plants under nursery conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009Agustina Bernal-Vicente Abstract BACKGROUND: The use of isolates of the genus Trichoderma to control Fusarium wilt in melon plants is one of the most recent and effective alternatives to chemical treatments. In this work we have studied the immobilization of the isolate Trichoderma harzianum T-78 on different carriers as an efficient method to control vascular Fusarium wilt of melon in nurseries. Different formulations were developed: liquids (spore suspension, guar gum and carboxymethylcellulose) and solids (bentonite, vermiculite and wheat bran). RESULTS: The introduction of F. oxysporum resulted in a significant decrease in seedling fresh weight. The treatments which gave a lesser reduction in weight and showing a greater biocontrol effect were the liquid conidial suspension and the solid treatments with bentonite and superficial vermiculite. Microbiological analyses revealed that the conidial suspension and all the solid treatments, except wheat bran, significantly decreased F. oxysporum populations. Of all the treatments assayed, bentonite produced the greatest decline in the F. oxysporum population. CONCLUSIONS: The most effective treatments against Fusarium wilt on melon plants were the solid treatments bentonite and superficial vermiculite. These two treatments gave the greatest plant weight, the lowest percentage of infected plants and the greatest T. harzianum population throughout the assay. Copyright © 2009 Society of Chemical Industry [source] Inhibition of aflatoxin B1 production of Aspergillus flavus, isolated from soybean seeds by certain natural plant productsLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2006Y.L. Krishnamurthy Abstract Aims:, The inhibitory effect of cowdung fumes, Captan, leaf powder of Withania somnifera, Hyptis suaveolens, Eucalyptus citriodora, peel powder of Citrus sinensis, Citrus medica and Punica granatum, neem cake and pongamia cake and spore suspension of Trichoderma harzianum and Aspergillus niger on aflatoxin B1 production by toxigenic strain of Aspergillus flavus isolated from soybean seeds was investigated. Methods and Results:, Soybean seed was treated with different natural products and fungicide captan and was inoculated with toxigenic strain of A. flavus and incubated for different periods. The results showed that all the treatments were effective in controlling aflatoxin B1 production. Captan, neem cake, spore suspension of T. harzianum, A. niger and combination of both reduced the level of aflatoxin B1 to a great extent. Leaf powder of W. somnifera, H. suaveolens, peel powder of C. sinensis, C. medica and pongamia cake also controlled the aflatoxin B1 production. Conclusions:, All the natural product treatments applied were significantly effective in inhibiting aflatoxin B1 production on soybean seeds by A. flavus. Significance and Impact of the Study:, These natural plant products may successfully replace chemical fungicides and provide an alternative method to protect soybean and other agricultural commodities from aflatoxin B1 production by A. flavus. [source] Genetic analysis of seedling resistance to Stagonospora nodorum blotch in selected tetraploid and hexaploid wheat genotypesPLANT BREEDING, Issue 2 2009P. K. Singh Abstract Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, is a major component of the leaf-spotting disease complex of wheat (Triticum aestivum L.) in the northern Great Plains of North America. This study was conducted, under controlled environmental conditions, to determine the inheritance of resistance to SNB in a diverse set of hexaploid and tetraploid wheat genotypes and to decipher the genic/allelic relationship among the resistance gene(s). Plants were inoculated at the two to three-leaf stages with a spore suspension of P. nodorum isolate Kelvington-SK and disease reaction was assessed 8 days after inoculation based on a lesion-type scale. Tests of the F1 and F2 generations and of F2 : 3 or F2 : 5 families indicated that a single recessive gene controlled resistance to SNB in both hexaploid and tetraploid resistance sources. Lack of segregation in intra-specific and inter-specific crosses between the hexaploid and the tetraploid resistant genotypes, indicated that these genetically diverse sources of resistance possess the same gene for resistance to SNB. Results of this study suggest that the wheat- P. nodorum interaction may follow the toxin model of the gene-for-gene hypothesis. [source] Effect of initial concentration of bacterial suspensions on their inactivation by high hydrostatic pressureINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2002S. Furukawa The effects of initial concentration [104,109 colony forming units (CFU) mL,1] on the inactivation of vegetative cell suspensions (Escherichia coli) and spore suspensions (Bacillus subtilis) by hydrostatic pressure treatment were investigated. The inactivation rates of E. coli and B. subtilis decreased as the initial concentration of cell and spore suspensions increased. In the practical application of hydrostatic pressure treatment, it was considered that the initial concentration of the bacteria suspensions should be as low as possible. [source] Biocontrol and Plant Pathogenic Fusarium oxysporum -Induced Changes in Phenolic Compounds in Tomato Leaves and RootsJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2007Y. Panina Abstract The biocontrol fungus Fusarium oxysporum strain CS-20 was previously shown to reduce the incidence of Fusarium wilt of tomato through an uncharacterized host-mediated response. As phenolic compounds are involved in the defence response of tomato to pathogens and other stressors, this work was undertaken to determine whether biocontrol strains induced changes in phenolic compounds in leaves and roots of tomato seedlings in the presence and absence of pathogenic F. oxysporum f. sp. lycopersici. Roots of intact tomato seedlings were placed in water or aqueous fungal spore suspensions. Two biocontrol F. oxysporum strains [CS-20 (host-mediated mechanism) and 85SK-1 (control mechanism unknown)] and two plant pathogenic strains of F. oxysporum f. sp. lycopersici Race 1 were used. After 24 or 72 h exposure, phenolic compounds were extracted from leaves and roots before identification by HPLC. There were significant qualitative and quantitative differences between the two sampling times. Compared with the control treatment, strain CS-20 significantly altered (usually increasing) the ferulic, caffeic and vanillic acid contents, and concentrations once unidentified phenolic compounds recovered from leaves and roots. In another experiment, tomato seedlings growing in sterile sand were drenched with spores of strain CS-20 the day before treating them with varying concentrations of spores of the pathogen for 24 or 72 h. The amount of pathogen present did not significantly affect the plant phenolic response to the presence of strain CS-20. This work demonstrates that tomato responds within 24 h to the presence of the biocontrol strain CS-20 by alterations in secondary metabolism that are typical of resistance responses in tomato. [source] Potential of Trichoderma harzianum and T. atroviride to Control Botryosphaeria berengeriana f. sp. piricola, the Cause of Apple Ring RotJOURNAL OF PHYTOPATHOLOGY, Issue 4-5 2002G. KEXIANG Abstract Trichoderma harzianum T88 and T. atroviride T95 were tested for their efficacy in controlling apple ring rot (caused by Botryosphaeria berengeriana f. sp. piricola) in vitro and in the field. Isolates of T88 and T95 produced both volatile and non-volatile antibiotics that suppressed mycelial growth of the pathogen. Light and scanning electron microscopy showed that mycoparasitism by Trichoderma spp. of B. berengeriana f. sp. piricola resulted in penetration and disruption of hyphal cells, and thinning of cytoplasm of the pathogen. The culture filtrates of T88 and T95 in Czapek's liquid medium suppressed conidial germination of the pathogen, and the germination level was negatively correlated with the duration of culture of Trichoderma. In inoculation tests, 32 days after simultaneous inoculation or preinoculation with B. berengeriana f. sp. piricola and Trichoderma spp., the incidence of infected apple shoots was reduced, respectively, by 65.3,76.4% and 62.5,76.4%, and the index of infection reduced by 36.9,38.9 and 40.7,44.4, The effect of inoculating B. berengeriana f. sp. piricola 3 days after the antagonists were inoculated was greater (81.4,88.8%) than simultaneous inoculation (72.2,77.8%). Re-isolation from inoculated apple shoots demonstrated that the pathogen had been suppressed by Trichoderma. The ability to re-isolate the pathogen from apple after co-inoculation and pre-inoculation with Trichoderma spp. was reduced by 27.0,42.3% and 22.2,47.1%, respectively. The biocontrol field trial suggested that the B. berengeriana f. sp. piricola canker on apple shoots and stems and rotting fruit had been efficiently controlled by the application of spore suspensions of T. harzianum T88 and T. atroviride T95. The efficacy of control by Trichoderma is thus similar to that of routine chemical control. [source] Berry infection and the development of bunch rot in grapes caused by Aspergillus carbonariusPLANT PATHOLOGY, Issue 2 2008B. A. Kazi The effects of different levels of inoculum of Aspergillus carbonarius and time of inoculation on berry infection and the development of aspergillus bunch rot on grapevines (cv. Sultana) were studied under field conditions. Inflorescences at full bloom were inoculated with aqueous spore suspensions of A. carbonarius containing 0 or 1 × 106 spores mL,1 in 2004/05 and 0, 1 × 102 or 1 × 105 spores mL,1 in 2005/06. In both years, the incidence of infection in inoculated berries was significantly higher than in uninoculated berries. Incidence of infection in berries from veraison until harvest was higher than at earlier stages of bunch development (berry set to berries that were still hard and green). Inoculation of bunches at veraison did not significantly increase A. carbonarius infection prior to harvest, at harvest, 6 days after harvest or when berries were over-ripe. Bunches inoculated at harvest did not significantly increase infection 6 days after harvest or when berries were over-ripe. Aspergillus carbonarius was isolated more frequently from the pedicel end (53·1%) than from the middle section (37·5%) and distal end (35·0%) of berries that were inoculated with 105 spores mL,1. [source] Effect of inoculum type and timing of application of Coniothyrium minitans on Sclerotinia sclerotiorum: control of sclerotinia disease in glasshouse lettucePLANT PATHOLOGY, Issue 5 2004E. E. Jones The effects of Coniothyrium minitans inoculum quality and an 8-week interval between inoculum application and crop planting on sclerotinia (Sclerotinia sclerotiorum) disease in three successive lettuce crops were investigated in a glasshouse trial. Spore suspensions of three isolates of C. minitans (Conio, IVT1 and Contans) applied at 108 CFU m,2 and a standard Conio maizemeal,perlite application (06 L m,2, 1011 CFU m,2) were assessed for their ability to control S. sclerotiorum. Only the maizemeal,perlite inoculum (isolate Conio) consistently reduced sclerotinia disease. In the third lettuce crop only, isolates IVT1 and Contans formulated by Prophyta and isolate IVT as an oil,water formulation, all applied as spore suspensions, reduced disease at harvest compared with the untreated control. Recovery, viability and C. minitans infection of sclerotia buried during the 8-week period prior to each of the three lettuce crops, and of sclerotia formed on the crop, were tested. Only the maizemeal,perlite inoculum (isolate Conio) reduced the recovery of sclerotia buried in soil for weeks between inoculum application and crop planting, reducing their viability and increasing infection by C. minitans. Eight weeks was sufficient to enable C. minitans to infect sclerotia of S. sclerotiorum, and may account for disease control. After harvest of the second and third crops, maizemeal,perlite treatment (isolate Conio) reduced the number and viability of sclerotia recovered on the soil surface and increased infection by C. minitans compared with spore-suspension treatments. The effect of inoculum concentration and the influence of soil temperature (varying with time of year) on infection of sclerotia by C. minitans are discussed. [source] Factors affecting the development of Botrytis cinerea (grey mould) on linseed (Linum usitatissimum) buds, flowers and capsulesANNALS OF APPLIED BIOLOGY, Issue 1 2002S A M FERRYMAN Summary A key was produced to describe 10 stages of development of linseed buds, flowers and capsules. Botrytis cinerea conidia germinated more rapidly and germ tubes grew longer on linseed stigmas, petals and mature senescing capsules than on green leaves, sepals and immature capsules. The proportion of conidia which germinated increased and the germ tubes continued growing for longer in the presence of linseed pollen and flower petal extracts. In controlled environment and field experiments, the response of buds, flowers and capsules to inoculation with B. cinerea changed with stage of development; few pre-flowering buds developed symptoms (brown lesions, then grey mould), but high proportions of flowering and post-flowering buds did so. Few immature green capsules developed symptoms and the proportion of capsules which developed symptoms increased as they matured. The presence of linseed pollen decreased the incubation period from inoculation with spore suspensions to appearance of B. cinerea symptoms on buds. A disease cycle was produced to suggest the changes in susceptibility of linseed to infection by B. cinerea conidia during bud, flower and capsule development. [source] | |||||||||||||||||||||||||