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A strain of Kalmusia variispora associated with grapevine trunk diseases (GTDs) was identified in Iran and induced disease symptoms on the host in greenhouse conditions. The grapevine pathogens are able to produce a plethora of toxic metabolites belonging to different classes of naturally occurring compounds. Two homogeneous compounds were isolated from the organic extract of K. variispora culture filtrates. They were identified by physic (specific optical rotation), and spectroscopic (essentially 1D 1H and 13C NMR and HR ESIMS) methods as the fungal polyketides massarilactones D and H (1 and 2). The unassigned absolute configuration of massarilactone D was unambiguously determined by X-ray diffractometric analysis. Massarilactones D and H showed phytotoxic activity on Vitis vinifera L. at two concentrations used and depending from the days of inoculation. Phytotoxicity is also increased when the 3,4,7-O,O',O"-triacetyl derivative of massarilactone D (3) was assayed on the host plant. This is the first report on the investigation of phytotoxic metabolites produced by K. variispora isolated from infected grapevine in Iran and they seem to be involved in the development of disease symptoms.

Grapevine trunk diseases (GTDs) are one of the most serious biotic stresses affecting this important crop. Among them a range of diseases were identified and associated to a plethora of phytopathogenic fungi, including species of Diaporthe. Diaporthe eres was recently identified as one of the species involved in cane blight of grapevine. The ability of a strain of this fungus isolated from infected grapevine plant in Italy to produce in vitro phytotoxic metabolites was investigated. Five phytotoxic metabolites were identified by their physical and spectroscopic properties as 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, nectriapyrone, p-cresol and tyrosol. When tested on grapevine leaf disks and by leaf absorption, 4-hydroxybenzoic acid induced symptoms on both disks and leaves, 4-hydroxybenzaldehyde and p-cresol showed, respectively, phytotoxicity on leaf disks and on the leaf absorption bioassay.

The organic extract of the aerial parts of Dittrichia viscosa, a perennial native plant of the Mediterranean basin, showed a significant acaricidal activity against Varroa destructor, the parasite mite of Apis mellifera, commonly called honey bee. Among the metabolites isolated from the organic extract of this Asteraceae, α-costic acid showed to be one of the compounds responsible for the toxic activity exhibited by the crude plant extract on this parasite mite species. In addition to the toxic effect a clear acaricidal response has been recorded when the parasitic mite was exposed to 1 mg/mL concentration of α-costic acid while no effects have been showed on honey bees using the same compound at the same concentration. This finding suggests a potential use of α-costic acid to control Varroa mites. The possibility to reliably achieve absolute configuration of α-costic acid by DFT computational analysis of chiroptical spectra has been also demonstrated.†

Aphids are noxious insect pests of major crops including cereals and legumes. Particularly, pea aphid (Acyrthosiphon pisum) causes significant yield and quality loses in pea. Crop protection is largely based on noxious chemical pesticides which have prompted a renewed interest in the discovery of natural products as alternatives to synthetic insecticides. In this study different classes of natural compounds were tested in dual choice bioassays to evaluate their feeding deterrence and mortality effect on pea aphid. High feeding deterrence was produced by some of the compounds, particularly1-hexadecanol, gliotoxin, cyclopaldic acid and seiridin. On the contrary, aphid mortality was low although significant for 1-heptadecanol, cytochalasin A, 1-nonadecanol and gliotoxin. Phytotoxicity assessment showed low or imperceptible plant damaged for cytochalasin A, seiridin and 1-nonadecanol. The results obtained showed the potential of seiridin to be used as an alternative to synthetic insecticides., This work was supported by the Spanish Ministry of Economy and Competitiveness FPI program and projects [grant number AGL2014-52871-R], [grant number AGL2017-82907-R]; the FEDER; the EU-FP7-LEGATO [grant number 613551].

Moulds food infestation is a heavy dangerous problem for human health and also could generate heavy economic losses. The intelligent packaging using eco-friendly biodegradable biofilm incorporating bioactive natural safe compounds represents a new frontier. This manuscript reports the inhibitory activity of 12 bacterial, fungal and plant metabolites against Penicillium roqueforti and Aspergillus niger. Among them α-costic acid and ungeremine (3 and 12) are the most promising as potential biofungicide against both fungal strains. They inhibited fungal growth by more than 60% respect to the control at 72 h and this activity persisted also at 96 h. Ungeremine showed MIC90 lower than 0.003 mg/mL after 48 h of incubation and of 0.025 mg/mL at 72 h against P. roqueforti. The MIC90 value for A. niger was 0.2 mg/mL at 48 h for both compounds. The α-costic acid showed generally MIC values at 48 and 72 h higher than ungeremine.

Cavoxin is a tetrasubstituted phytotoxic chalcone and cavoxone is the corresponding chroman-4-one, both produced in vitro by Phoma cava, a fungus isolated from chestnut. Cavoxin showed biofungicide potential against fungal species responsible for food moulding. Therefore, cavoxin has potential to be incorporated into biopolymer to generate ‘intelligent food packaging’. To reach this objective, large-scale production of cavoxin by P. cava fermentation needs to be optimized. A rapid and efficient method for cavoxin analysis, as well as of cavoxone, in the fungal culture filtrates and the corresponding organic extracts is the first experimental step. Thus, a HPLC method was developed and applied to quantify cavoxin and cavoxone production in two different fungal culture conditions. The analysis proved that cavoxin production in stirred culture filtrates is significantly higher than in static ones.