Direct Tissue Blot Immunoassay for Analysis of Plant Pathogens *

2017 ◽  
pp. 367-376
Author(s):  
H. T. Hsu ◽  
R. H. Lawson ◽  
N. S. Lin ◽  
Y. H. Hsu
Keyword(s):  
Plant Pathogens ◽  
Tissue Blot Immunoassay

Freeze substitution fixation of fungal reproductive structures and spores

1989 ◽  
Vol 47 ◽  
pp. 990-991
Author(s):  
C. W. Mims ◽  
E. A. Richardson
Keyword(s):  
Plant Pathogens ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Dialysis Membrane ◽  
Razor Blade ◽  
Thin Sections ◽  
Reproductive Structures ◽  
Dry Down ◽  
Diamond Knife

The advantages of freeze substitution fixation over conventional chemical fixation for preservation of ultrastructural details in fungi have been discussed by various authors. As most ascomycetes, basidiomycetes and deuteromycetes do not fix well using conventional chemical fixation protocols, freeze substitution has attracted the attention of many individuals interested in fungal ultrastructure. Thus far most workers using this technique on fungi have concentrated on thin walled somatic hyphae. However, in our laboratory we have experimented with the use of freeze substitution on a variety of fungal reproductive structures and spores with promising results.Here we present data on freeze substituted samples of sporangia of the zygomycete Umbellopsis vinacea, basidia of Exobasidium camelliae var. gracilis, developing teliospores of the smut Sporisorium sorghi, germinating teliospores of the rust Gymnosporangium clavipes, germinating conidia of the deuteromycete Cercosporidium personatum, and developing ascospores of Ascodesmis nigricans.Spores of G. clavipes and C. personatum were deposited on moist pieces of sterile dialysis membrane where they hydrated and germinated. Asci of A. nigricans developed on pieces of dialysis membrane lying on nutrient agar plates. U. vinacea was cultured on small pieces of agar-coated wire. In the plant pathogens E. camelliae var. gracilis and S. sorghi, a razor blade was used to remove smal1 pieces of infected host issue. All samples were plunged directly into liquid propane and processed for study according to Hoch.l Samples on dialysis membrane were flat embedded. Serial thin sections were cut using a diamond knife, collected on slot grids, and allowed to dry down onto Formvar coated aluminum racks. Sections were post stained with uranyl acetate and lead citrate.

Effect of Homeopathic Preparations on Lettuce, Parasitized or Not by Meloidogyne enterolobii

Homeopathy ◽  
2020 ◽  
Author(s):  
Thais Moraes Ferreira ◽  
Mariana Zandomênico Mangeiro ◽  
Alexandre Macedo Almeida ◽  
Ricardo Moreira Souza
Keyword(s):  
Plant Pathogens ◽  
Nematode Control ◽  
Plant Tolerance ◽  
Nematode Reproduction ◽  
Meloidogyne Enterolobii ◽  
Negative Effect ◽  
Meloidogyne Spp ◽  
Constant Dose ◽  
Lettuce Growth ◽  
Complementary Strategy

Abstract Background There are relatively few scientific works on the use of homeopathy to manage plant pathogens, particularly nematodes. A handful of studies focused on Meloidogyne spp. parasitizing vegetables have brought contradictory results on nematode control and enhancement of plant tolerance to parasitism. Objective Our goal was to assess the effect of Cina—a well-known anti-nematode ingredient—on Meloidogyne enterolobii parasitizing lettuce. Methods Cina was applied daily on nematode-inoculated plants, from the seedling stage until harvest. We tested an evenly spaced range of Hahnemannian concentrations (c), which were applied though irrigation with a constant dose of the ingredient. Several absolute and relative controls were employed to allow the assessment of the effect of Cina on nematode reproduction and lettuce growth. Results Cina affected growth of non-parasitized plants, both positively and negatively; this effect was modulated by the c applied and the thermal stress suffered by the plants in one of the assays. The effect of Cina on the growth of nematode-parasitized plants was neutral or negative. Cina reduced nematode reproduction by 25–36%. Conclusion Based on the moderate negative effect of Cina on M. enterolobii reproduction, it seems this ingredient may be useful as a complementary strategy for Meloidogyne control. But Cina did not enhance the tolerance of lettuce to Meloidogyne spp.

Effect of C6-Volatiles on Bioluminescent Plant Pathogens

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557d-557
Author(s):  
Jennifer Warr ◽  
Fenny Dane ◽  
Bob Ebel
Keyword(s):  
Biological Activity ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Genetically Engineered ◽  
The Other ◽  
Computer Assisted ◽  
Signal Molecules ◽  
Low Concentrations

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.

Studies on the EC50 of Natural Monoterpenes as Fungal Inhibitors with Quantitative Structure-Activity Relationships (QSARs)

2020 ◽  
Vol 10 (1) ◽  
pp. 44-60
Author(s):  
Mohamed E.I. Badawy ◽  
Entsar I. Rabea ◽  
Samir A.M. Abdelgaleil
Keyword(s):  
Biological Activity ◽  
Plant Pathogens ◽  
Molecular Descriptors ◽  
Microbial Pathogens ◽  
Quantitative Structure ◽  
Qsar Study ◽  
Qsar Analysis ◽  
Pharmacophore Modelling ◽  
Structure Activity ◽  
Wide Range

Background:Monoterpenes are the main constituents of the essential oils obtained from plants. These natural products offered wide spectra of biological activity and extensively tested against microbial pathogens and other agricultural pests.Methods:Antifungal activity of 10 monoterpenes, including two hydrocarbons (camphene and (S)- limonene) and eight oxygenated hydrocarbons ((R)-camphor, (R)-carvone, (S)-fenchone, geraniol, (R)-linalool, (+)-menthol, menthone, and thymol), was determined against fungi of Alternaria alternata, Botrytis cinerea, Botryodiplodia theobromae, Fusarium graminearum, Phoma exigua, Phytophthora infestans, and Sclerotinia sclerotiorum by the mycelia radial growth technique. Subsequently, Quantitative Structure-Activity Relationship (QSAR) analysis using different molecular descriptors with multiple regression analysis based on systematic search and LOOCV technique was performed. Moreover, pharmacophore modelling was carried out using LigandScout software to evaluate the common features essential for the activity and the hypothetical geometries adopted by these ligands in their most active forms.Results:The results showed that the antifungal activities were high, but depended on the chemical structure and the type of microorganism. Thymol showed the highest effect against all fungi tested with respective EC50 in the range of 10-86 mg/L. The QSAR study proved that the molecular descriptors HBA, MR, Pz, tPSA, and Vp were correlated positively with the biological activity in all of the best models with a correlation coefficient (r) ≥ 0.98 and cross-validated values (Q2) ≥ 0.77.Conclusion:The results of this work offer the opportunity to choose monoterpenes with preferential antimicrobial activity against a wide range of plant pathogens.

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