Fungi are an extraordinary and immensely diverse group of microorganisms that colonize many habitats even competing with other microorganisms. Fungi have received recognition for interesting metabolic activities that have an enormous variety of biotechnological applications. Previously, volatile organic compounds produced by fungi (FVOCs) have been demonstrated to have a great capacity for use as antagonist products against plant pathogens. However, in recent years, FVOCs have been received attention as potential alternatives to the use of traditional pesticides and, therefore, as important eco-friendly biotechnological tools to control plant pathogens. Therefore, highlighting the current state of knowledge of these fascinating FVOCs, the actual detection techniques and the bioactivity against plant pathogens is essential to the discovery of new products that can be used as biopesticides.

No abstract

BACKGROUND: 'Murtilla', 'mutilla' or 'murta' (Ugni molinae Turcz) is a native Chilean species that produces a small berry fruit with a special aroma, whose volatile compounds have not yet been identified. The fruit may be consumed raw and also as jams, juice, canned products, confections and liquor.

No abstract

Seven compounds belonging to different structural skeletons were isolated from Microsphaeropsis olivacea grown in liquid and solid media. The enalin derivative 7-hydroxy-2,4- dimethyl-3(2H)-benzofuranone is reported for the first time, while additional spectroscopic information is provided for the acetates of botrallin and ulocladol. The activity of the isolated compounds was assessed towards the enzyme acetylcholinesterase (AChE) and their cytotoxicity against human lung fibroblasts. Graphislactone A and botrallin presented a moderate activity towards AChE, with IC50 of 8.1 and 6.1 μg/ml (27 and 19 μᴍ, respectively). Under the same experimental conditions, the IC50 of the standard inhibitor galanthamine was 3 μg/ml. The cytotoxicity of both compounds was > 1000 and 330 μᴍ, respectively. None of the compounds was promising as antibacterial or antifungic against phytopathogenic fungi and bacteria. Botrallin and graphislactone A were detected in the liquid potato-dextrose and yeast extract/ malt extract/dextrose as well as on a solid substrate (rice). Butyrolactone I was obtained from the fungus growing on solid medium.

Thirty-eight endophytic fungi were isolated from eight Chilean gymnosperms. Isolates were characterized and grouped according to culture characteristics, colony growth, and conidia morphology. Thirteen isolates were identified: Acremonium bacillisporum, A. bactrocephalum, A. strictum, Alternaria alternata, Aureobasidium pullulans, Chaetomium funicola, Cladosporium tenuissimum, Curvularia protuberata, C. tritici, Microsphaeropsis olivacea, Penicillium chrysogenum, P. janczewskii, and Triblidiopycnis pinastri. Malbranchea and Stegonosporium were identified at the genus level. Fourteen isolates, considered to be sterile mycelia, did not fructify in the culture medium. Crude extracts of liquid cultures from endophytes were examined for antibacterial and antifungal activity against bacteria and phytopathogenic fungi using agar diffusion. Antifungal activity against pathogenic fungi was determined by microdilution assays. Extracts of Acremonium bactrocephalum, Microsphaeropsis olivacea, and isolate E-3 inhibited growth of selected pathogenic organisms, indicating they merit further study. This is the first comparative report on the antimicrobial activity of endophytic fungi from Chilean gymnosperms.

Penicillium janczewskiiK. M. Zalessky was isolated as an endophytic fungus from the phloem of the Chilean gymnosperm Prumnopitys andina. When grown in liquid yeast extractmalt extract-glucose broth, the fungus produced two main secondary metabolites. The compounds were for the first time isolated from this species and identified by spectroscopic methods as pseurotin A and cycloaspeptide A. This is the first report on the production of cyclic peptides by endophytic fungi from Chilean gymnosperms. Pseurotin A and cycloaspeptide A presented low cytotoxicity towards human lung fibroblasts with IC50 ≥ 1000 μm. Pseurotin A showed a moderate effect against the phytopathogenic bacteria Erwinia carotovora and Pseudomonas syringae, with IC50 values of 220 and 112 μg ml-1, respectively.

In Chile, the horn fly, Hematobia irritans (L., 1758), is a major pest of grazing cattle and affects livestock production during the summer. Previous studies in Europe and the United States have shown that cattle flies, including H. irritans, are differentially attracted to individual cattle within herds and that volatile semiochemicals are responsible for this phenomenon. This study provides evidence that similar differential attractiveness occurs for the interaction between Chilean Holstein-Friesian cattle herds and local H. irritans populations. Thus, Holstein-Friesian dairy cattle, Bos taurus, which were of similar age and physiological condition, were shown to possess an uneven distribution of H. irritans. Heifers h6904 and h8104 were defined as low-carrier heifers and h5804, h2304 and h1404 as high-carrier heifers. Gas chromatography (GC) and coupled GC-mass spectrometric (GC-MS) analysis of samples collected from heifers revealed the presence of compounds previously reported as semiochemicals for cattle flies, including meta- and para-cresol, methylketones (C8-C11), and 6-methyl-5-hepten-2-one. Other compounds identified included carboxylic acids (butanoic, 3-methylbutanoic, pentanoic, and hexanoic acids), 1-hexanol, and 3-octanone. In Y-tube olfactometer studies, both m- and p-cresol attracted H. irritans at the highest doses tested (10(-6) g), as did the positive control 1-octen-3-ol. Of the other compounds tested, only 2-decanone and 2-undecanone produced a behavioral response, with significantly more flies being recorded in the control arm when the former compound was tested (at 10(-6) and 10(-8) g), and more flies being recorded in the treated arm for the latter compound (at 10(-7) g). This demonstration of behavioral activity with the identified compounds represents a first step for research into the application of semiochemicals in monitoring and control of cattle flies in Chile.