Photoprotector adjuvants to enhance UV tolerance of yeast strains for controlling mango decay using pre-harvest spraying

Post-harvest mango decay is caused by multiple pathogens in tropical conditions but concerns regarding the risk of food contamination by fungicides established biocontrol as a promising alternative. However, occurrence of quiescent infections requires pre-harvest applications of biocontrol agents (BCA), exposing them to harmful UV radiation effects. The objective of this work was to evaluate UV sensitivity of yeast BCA strains previously selected against multiple pathogens that cause mango decay and evaluate suitable UV protectants. In a first bioassay conducted exposing yeast suspensions sprayed on glass plates, it was verified that Saccharomyces sp. ESA47 and Pichia kudriavzevii CMIAT171 were highly sensitive to UV, while Saccharomyces cerevisiae ESA45 had a slightly lower mortality. A bioassay using fragments of mango peels evaluated UV protection from increasing concentrations of starch, dextrin, casein, benzophenone, and cinnamic acid derivative compounds. Results showed that starch and isoamyl p-methoxycinnamate (NHE-1000) resulted in higher survival for yeast strains in doses of 10.0 and 1.0?g?kg^?1, respectively. Application of the yeast BCA in a semi-commercial mango orchard resulted in a significant reduction of post-harvest disease incidence and severity. Field application of the yeasts in technical grade preparations containing both UV protectants enhanced the control efficiency by 52.5, 31.9, and 37.7% for ESA45, ESA47, and CMIAT171, respectively.     

Symbionts mediate oviposition behaviour in invasive and native woodwasps

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Morphological variants of Moniliophthora roreri on artificial media and the biotroph/necrotroph shift

Moniliophthora roreri (Mr) causes frosty pod rot of Theobroma cacao in a hemibiotrophic association. The Mr biotroph-like phase has not been studied in culture. Mr spores (isolates Co12, Co52, and B3) were germinated on high (V8) and low (BPMM) nutrients with different media hardness (0.5% to 3% agarose). Germination was high on V8 media. Hardness affected germination on BPMM. Most colonies on V8 were slow-growing, failing to sporulate. Colony morphology depended on the isolate. On BPMM, exaggerated mycelia formed of limited length with enlarged cells. On agarose, rapidly expanding sporulating necrotrophic colonies formed rarely. Co12 and B3 spores were germinated on V8 and BPMM with low melting point (LMP) agarose. Slow-growing colonies of B3 on BPMM were unstable on LMP agarose, often forming slow-growing/rapidly expanding hybrids. Slow-growing colonies are hypothesized to represent the biotrophic phase. One nucleus was common in Mr cells, other than spores. Binucleate cells were occasionally observed in aged cells of slow-growing mycelia. Co52 cells often had more than two nuclei per cell after germination. Mr mycelia cells typically carry a single nucleus, being considered haploid. Biotroph- and necrotroph-like mycelia displayed differential gene expression but results were inconsistent with published in vivo results and require further study.     

Temperature effects on hyphal growth of wood-decay basidiomycetes isolated from Pinus densiflora deadwood

Hyphal growth rates were tested on malt extract agar plates at eight different temperatures (5–40?°C) using 36 isolates of 17 basidiomycete species obtained from Pinus densiflora deadwood in Japan. All isolates of four brown rot species showed optimum growth at 30?°C, whereas the optimum growth temperature of white rot species varied from 20?°C to 30?°C. Analysis using a dataset from four cooler sites showed that brown rot fungi grew more rapidly than white rot fungi at higher temperatures (25?°C, 30?°C, and 35?°C). These results suggest that the hyphal growth of brown rot fungi might be physiologically adapted to higher temperatures than those of white rot fungi among the fungal species inhabiting deadwood of P. densiflora in Japan.     

White rot fungi and advanced combined biotechnology with nanomaterials: promising tools for endocrine-disrupting compounds biotransformation

Endocrine-disrupting compounds (EDCs) can interfere with endocrine systems and bio-accumulate through the food chain and even decrease biodiversity in contaminated areas. This review discusses a critical overview of recent research progress in the biotransformation of EDCs (including polychlorinated biphenyl and nonylphenol, and suspected EDCs such as heavy metals and sulfonamide antibiotics) by white rot fungi (WRF) based on techniques with an emphasis on summarizing and analyzing fungal molecular, metabolic and genetic mechanisms. Not only intracellular metabolism which seems to perform essential roles in the ability of WRF to transform EDCs, but also advanced applications are deeply discussed. This review mainly reveals the removal pathway of heavy metal and antibiotic pollutants because the single pollution almost did not exist in a real environment while the combined pollution has become more serious and close to people’s life. The trends in WRF technology and its related advanced applications which use the combined technology, including biocatalysis of WRF and adsorption of nanomaterials, to degrade EDCs have also been introduced. Furthermore, challenges and future research needs EDCs biotransformation by WRF are also discussed. This research, referring to metabolic mechanisms and the combined technology of WRF with nanomaterials, undoubtedly contributes to the applications of biotechnology. This review will be of great benefit to an understanding of the trends in biotechnology for the removal of EDCs.     

ICP-AES analysis in sesame on the root rot disease incidence

Five different sesame varieties namely CO-1, VRI-1, VRI-2, TMV-3 and TMV-4 are grown in different trial plots with three treatments viz., control (T₁), chemical fertiliser (T₂) and organic manure (T₃). Diseased and healthy roots are collected fieldwide using standard procedures. Roots are subjected to ICP-AES analysis and the elemental status of the diseased and healthy roots are estimated. A correlation between the elements (Ca, K, Na, Mg, Fe, Cu, Zn) of healthy and diseased plants with reference to manure treatment and different varieties has been attempted. It could be suggested that lowering the concentration of Ca, Na, Mg and Fe and increasing the concentration of K, Cu and Zn in the soil with T₃ treatment may very much reduce root rot disease occurrence.     

Outbreak of basal stem rot and wilt disease of pepper in Katsina,Nigeria

Abstract

A survey was conducted in February 2004 on the outbreak of stem rot and wilt disease of pepper at the Kitabawa/Danzakara and Ajiwa irrigation sites in Katsina State, Nigeria. Laboratory investigations revealed that it was elicited by Phytophthora capsici (Leon). The disease caused severe loss in yield and $1,700.00 to $3,200.00 loss in revenue/ha. The pathogen was probably further aggravated by the presence of Fusarium sp. as well as ecto- and endo-parasitic nematodes. Reasons for the outbreak were elucidated and solutions proffered.     

Vermicompost-based bioformulation for the management of sugarbeet root rot caused by Sclerotium rolfsii

Vermicompost-based bioformulations of bacterial and fungal biocontrol agents were examined against sugarbeet root rot caused by Sclerotium rolfsii. The result showed that the Pseudomonas fluorescens strain Pf1 in combination with either Trichoderma asperellum strain TTH1 or Bacillus subtilis strain EPCO-16 performed better in reducing disease next to the chemical difenoconazole. Similarly, enhanced yield was observed in the same combination treatments under both pot and field conditions.     

In vitro antifungal activity of chitinolytic enzymes produced by bio-agents against root rot pathogenic fungi

A study was carried out using simple laboratory techniques to examine the influence of the antagonistic isolates of Trichoderma harzianum, T. viride, Bacillius subtilis and Pseudomons flourescence and their culture filtrates on selected soil-borne root rot pathogens Rhizoctonia solani and Fusarium solani. Testing procedures were standardised using two different methods. The experiments were based on the principle of dual culture and agar diffusion techniques. The experiment involved the recording of the percentage of reduction in growth and inhibition zones formed by various filtrates of antagonistic culture growth. The results showed that the antagonists tested had the ability to reduce the linear growth of fungal pathogens. Also, the cultures filtrates of antagonists had antifungal activities by forming inhibition zones. Culture filtrates have shown a strong clear inhibition zone which increases in diameter as the incubation period of antagonists increases. This observation was related to the increase in the activity of chitinolytic enzymes as secondary metabolic compounds produced in growth media by prolonging the period of incubation. The study has proved that such enzymes can be effectively used for suppression of soil-borne pathogens and that it can evolve as a potential biocide.