Complete Abolition of High Inoculum Threshold of Two Mycoherbicides (<i>Alternaria cassiae</i>and<i>A. crassa</i>) When Applied in Invert Emulsion

Amsellem, Ziva; Sharon, Amir; Gressel, Jonathan; Quimby, P. C.

doi:10.1094/phyto-80-925

Cited by 64 publications

(30 citation statements)

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“…Musco, (Rohm and Hass, Springhouse, PA) and subsequently were propagated and grown as previously described (1). Alternaria cassiae Jurair & Khan was provided by Dr. C. D. Boyette (USDA, Stoneville, MS).…”

Section: Plants and Fungal Materialsmentioning

confidence: 99%

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Isolation, Purification, and Identification of 2-(p-Hydroxyphenoxy)-5, 7-Dihydroxychromone: A Fungal-Induced Phytoalexin from Cassia obtusifolia

Sharon¹,

Ghirlando²,

Gressel³

1992

Plant Physiol.

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A single phytoalexin was isolated and purified from 12-to 14-day-old leaves of Cassia obtusifolia L. inoculated with Afternaria cassiae Jurair & Khan. The structure was elucidated by 'H-and 13C-nuclear magnetic resonance and mass spectrometry as 2-(phydroxyphenoxy)-5,7-dihydroxychromone. The compound was shown to be derived in part from phenylalanine. Radial MATERIALS AND METHODS Plants and Fungal MaterialsSeeds of Cassia obtusifolia L. were provided by V.A. Musco, (Rohm and Hass, Springhouse, PA) and subsequently were propagated and grown as previously described (1). Alternaria cassiae Jurair & Khan was provided by Dr. C. D. Boyette (USDA, Stoneville, MS). Fungus was cultured and conidia produced as previously described (1). Plants were inoculated by spraying 12-to 14-d-old plants to run-off with a water suspension containing 0.02% Tween 80 and 105 conidia/mL. The control plants were sprayed with 0.02% Tween 80. The plants were incubated in a dew chamber (100% RH) for 16 h and then were moved to a high humidity (60-80% RH) greenhouse as described earlier (1). Leaves were harvested directly into extractant 48 h after inoculation. Purification of the PhytoalexinLeaves were extracted overnight at room temperature in the dark with 10 volumes of 90% methanol based on fresh weight (80% methanol final concentration). The leaves were then separated from the solvent and extracted again for 5 min with 2 volumes (v/w) of 90% methanol. The extracts were pooled, and the methanol was evaporated under reduced pressure at 45°C, leaving an aqueous residue. The residue was brought to 10 mL/g initial fresh weight with glass-distilled water and centrifuged for 30 min at 20,000g. The pellet was discarded, and the aqueous material was partitioned three times against ethyl acetate (1:1, v/v). No antifungal activity was found in the aqueous phase after partitioning, nor in the pellet. The organic phases were pooled and dried in vacuo. Part of the crude residue of the organic phase was loaded onto a 0.2 mm silica gel G254 TLC plate (Merck), developed for 7 cm with ethyl acetate:methanol (96:4), and directly bioassayed as described below. Part was redissolved in 1 mL of 70% methanol and chromatographed on a Sephadex LH-20 column (0.8 x 30 cm) with 70% methanol at a flow rate of 13.5 mL/h. The column was washed with 300 mL of pure methanol and equilibrated with 200 mL of 70% methanol after each run. An aliquot from each fraction was loaded onto a TLC plate, and the plate was developed with ethyl acetate:methanol (96:4). The presence ofthe putative phytoalexin was detected by the yellow fluorescence after spraying the plate with 1% AlCl3 in absolute ethanol ( 17).

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Section: Plants and Fungal Materialsmentioning

confidence: 99%

“…The control plants were sprayed with 0.02% Tween 80. The plants were incubated in a dew chamber (100% RH) for 16 h and then were moved to a high humidity (60-80% RH) greenhouse as described earlier (1). Leaves were harvested directly into extractant 48 h after inoculation.…”

Section: Plants and Fungal Materialsmentioning

confidence: 99%

Isolation, Purification, and Identification of 2-(p-Hydroxyphenoxy)-5, 7-Dihydroxychromone: A Fungal-Induced Phytoalexin from Cassia obtusifolia

Sharon¹,

Ghirlando²,

Gressel³

1992

Plant Physiol.

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“…This is particularly beneficial for organisms that are sensitive to desiccation. Some examples of successful application of W/O emulsions for formulation of microorganisms for improved delivery include formulation of the mycoherbicides Alternaria cassiae, A. crassa and Colletotrichum truncatum (Quimby et al, 1989;Amsellem et al, 1990;Boyette, 1994;Egley and Boyette, 1995) and formulation of Fusarium lateritium for control of Eutypa dieback in grapevine (Ho et al, 2005). A W/O emulsion of Ascochyta pteridis was produced using soybean and paraffin oils, and paraffin wax (Womack and Burge, 1993;Womack et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Water-in-oil emulsions that improve the storage and delivery of the biolarvacide Lagenidium giganteum

et al. 2006

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Lagenidium giganteum is an effective biological control agent for mosquitoes with limited use due to poor survival and contamination during storage. Invert (waterin-oil) emulsions using crop oils were investigated for formulating L. giganteum mycelium for improved shelf life and delivery. Cells formulated in a water-in-oil (W/O) emulsion were just as effective against larvae as those formulated in aqueous suspension. Cells formulated in the W/O emulsion and cell suspension settled during storage and formed clumps, which significantly reduced the efficacy of formulations. Hydrophobic silica nanoparticles were added to the W/O emulsion formulation for oil thickening. The addition of silica significantly reduced cell sedimentation and improved storage; thickened W/O emulsions with an initial cell density of 3900 CFU/mg applied at 0.5 mg/cm 2 were greater than 95% effective at infecting mosquitoes after 12 weeks of storage at room temperature. Cell density reduction during storage was represented using first-order kinetics. Surface treatment of silica nanoparticles and oil refinement both had a significant effect on the first-order rate constant; as the hydrophobicity of the silica increased and level of oil refinement decreased, the rate constant increased. The percentage of water in the W/O emulsion and type of refined crop oil had no significant effect on the first-order rate constant. Cells formulated in the thickened W/O emulsion were less likely to settle when applied to water compared to cells in aqueous suspension, suggesting better cell distribution in an aqueous environment could be achieved when cells are applied in a W/O emulsion.

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“…Although the host range was also altered to include some solanaceous crops, the pathogen could still be used with these crops if the timing of the applications was carefully considered. Formulation with invert emulsions expanded the host range of Alternaria cassiae (Amsellam et al, 1990) and Colletotrichum truncatum and C. gloeosporioides f. sp. aeschynomone Boyette et al, 1992).…”

Section: Risks Associated With Bioherbicidesmentioning

confidence: 99%

Bioherbicides: Research and Risks

Hoagland¹,

Boyette²,

Weaver³

et al. 2007

Toxin Reviews

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Complete Abolition of High Inoculum Threshold of Two Mycoherbicides (Alternaria cassiaeandA. crassa) When Applied in Invert Emulsion

Cited by 64 publications

References 0 publications

Isolation, Purification, and Identification of 2-(p-Hydroxyphenoxy)-5, 7-Dihydroxychromone: A Fungal-Induced Phytoalexin from Cassia obtusifolia

Isolation, Purification, and Identification of 2-(p-Hydroxyphenoxy)-5, 7-Dihydroxychromone: A Fungal-Induced Phytoalexin from Cassia obtusifolia

Water-in-oil emulsions that improve the storage and delivery of the biolarvacide Lagenidium giganteum

Bioherbicides: Research and Risks

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