Gulypyrones A and B and phomentrioloxins B and C produced by Diaporthe gulyae, a potential mycoherbicide for saffron thistle (Carthamus lanatus)

A virulent strain of Diaporthe gulyae, isolated from stem cankers of sunflower and known to be pathogenic to saffron thistle, has been shown to produce both known and previously undescribed metabolites when grown in either static liquid culture or a bioreactor. Together with phomentrioloxin, a phytotoxic geranylcyclohexenetriol recently isolated from a strain of Phomopsis sp., two new phytotoxic trisubstituted α-pyrones, named gulypyrones A and B (1 and 2), and two new 1,O- and 2,O-dehydro derivatives of phomentrioloxin, named phomentrioloxins B and C (3 and 4), were isolated from the liquid culture filtrates of D. gulyae. These four metabolites were characterized as 6-[(2S)2-hydroxy-1-methylpropyl]-4-methoxy-5-methylpyran-2-one (1), 6-[(1E)-3-hydroxy-1-methylpropenyl]- 4-methoxy-3-methylpyran-2-one (2), 4,6-dihydroxy-5-methoxy-2-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-2-enone (3), and 2,5-dihydroxy-6-methoxy-3-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-3-enone (4) using spectroscopic and chemical methods. The absolute configuration of the hydroxylated secondary carbon of the 2-hydroxy-1-methylpropyl side chain at C-6 of gulypyrone A was determined as S by applying a modified Mosher’s method. Other well-known metabolites were also isolated including 3-nitropropionic, succinic, and p-hydroxy- and p-methylbenzoic acids, p-hydroxybenzaldehyde, and nectriapyrone. When assayed using a 5 mM concentration on punctured leaf disks of weedy and crop plants, apart from 3-nitropropionic acid (the main metabolite responsible for the strong phytotoxicity of the culture filtrate), phomentrioloxin B caused small, but clear, necrotic spots on a number of plant species, whereas gulypyrone A caused leaf necrosis on Helianthus annuus plantlets. All other compounds were weakly active or inactive

Antioxidant response in Chenopodium album elicited by Ascochyta caulina mycoherbicide phytotoxins

Antioxidant defence responses were evaluated in Chenopodium album plants treated with a mixture of the phytotoxins ascaulitoxin, 2,4,7-triamino-5-hydroxyoctandioic acid (ascaulitoxin aglycone) and trans-4-aminoproline, produced by the pathogenic fungus Ascochyta caulina, previously proposed as mycoherbicide for this noxious weed. The enzymatic and non-enzymatic effects of these phytotoxins on the ascorbate system and on catalase activity were assessed by evaluating their biological and specific activities through spectrophotometric and electrophoretic analyses. In addition, the oxidative status was monitored through evaluating H2O2 content during the time-course. The mixture of toxins induced high levels of H2O2 accumulation resulting in an oxidative burst in the plant cells. Ascorbate peroxidase and catalase had crucial roles in detoxifying H2O2. The persisting metabolic perturbations, however, led to severe necrosis and death of C. album plants. The induced H2O2 production may be generated by the fungus as part of its necrotrophic nature. This study explains the defence responses in C. album to the mycoherbicide, in particular, the ascorbate systems’ components and H2O2 as an index of oxidative stress

Phytotoxins produced by Pestalotiopsis guepinii, the causal agent of hazelnut twig blight

The main lipophilic phytotoxic metabolite was isolated from the culture filtrates of Pestalotiopsis guepinii, the fungus causing twig blight of hazelnut. The metabolite was spectroscopically identified as pestalopyrone, a pentaketide that it was originally identified as a minor toxin produced by Pestalotiopsis oenotherae. The toxic activity of pestalopyrone was compared with that of nectriapyrone, a structurally related monoterpenoid recently isolated from Phomopsis foeniculi, and that of the new dihydro-derivative of nectriapyrone. The high phytotoxic activity of nectriapyrone and its dihydro-derivative on three non host  plants, showed that the double bond of the 1-methylpropenyl group at C-6 of the aromatic ring is inessential for its activity, while the much lower activity of pestalopyrone showed that the methyl group at C-3 of the same ring is an important structural feature. The high molecular weight hydrophilic phytotoxins produced by this fungus are reported for the first time

Creare valore nella supply chain: Modelli di gestione a confronto

A partire dagli anni Settanta, l’affermarsi della dimensione mondiale nell’attività economica si è accompagnato alla progressiva creazione di reti globali di produzione. Sebbene la globalizzazione abbia favorito un’ampia crescita economica ed evidenti miglioramenti nei livelli educativi, igienici e sanitari in quei paesi in via di sviluppo che hanno progressivamente partecipato alla nuova divisione internazionale del lavoro, la competizione tra aree produttive per l’ottenimento di capitali, clienti e insediamenti ha assunto proporzioni inaspettate. In tale contesto, la gestione della filiera produttiva è diventata un prerequisito essenziale per competere a livello nazionale e globale, beneficiando dei vantaggi derivanti dalla globalizzazione. Partendo da tali premesse, la ricerca punta all’approfondimento delle dinamiche in atto nella gestione della filiera produttiva, attraverso la comparazione tra settori in cui la contrapposizione tra modelli concorrenziali alternativi è particolarmente evidente, tra produzioni basate sul prezzo e rappresentative di una competizione sui costi (cost-driven supply chain competition) e produzioni a più alto valore aggiunto, espressione di una competizione basata sul valore (value-driven supply chain competition). Emergono, dunque, interessanti spunti di riflessione tanto per gli studiosi che intendono approfondire la gestione della supply chain, quanto per i manager che intendono approfondire nuovi modelli di gestione

Weeds in Non-Agricultural Areas: How to Evaluate the Impact? A Preliminary Case Study in Archaeological Sites

The term “weeds” refers to “plants suitable for habitats modified by man and that interfere with human activities”. It implies an anthropocentric rather than an ecological vision since the existence and the characteristic of the interference depends on men’s purposes. In the archaeological sites, the most important damage is the functional one and it ranges from hazards for the structures to the interference that weed flora can exert on the technical management and fruition of the site. In this particular type of environment, the diverse methods available to quantify the magnitude of the infestation are not sufficient to describe the potential or actual hazard to which a given infested site is subjected. Therefore, it is necessary to consider a greater degree of detail (including morphological, ecological, and physiological properties of the weeds) and to keep them all in consideration. The aim of the present work was to try to identify and propose a method for the assessment of the hazards and thus the damages that a weed community can lead in sites of historical and archaeological interest. The procedure quantifies the degree of the infestation, in terms of occurring species, quantifies the related hazard based on some traits of the weed species, and calculates indexes capable of providing synthetic and comparable information on the hazard to which the site is exposed. The proposed method was applied and tested in some sites of archaeological interest in the Apulia Region, in southern Italy. Applied to the surveyed archaeological sites, the proposed Indexes revealed the presence of weed infestations variously assorted in terms of potential damage, generating different hazard scores. This confirms the importance of understanding the type of infestation and not only its extent. In this study, a procedure was provided that can support decision-makers. Although studied for archaeological sites, the same principles adopted in this procedure could be proposed for other non-agricultural areas

Advances in Parasitic Weeds Research

Parasitic weeds are severe constraint to agriculture and major crop production, and the efficacy of available means to control them is minimal. Control strategies have centred around agronomic practices, resistant varieties and the use of herbicides. Novel integrated control programmes should be sympathetic to agricultural extensification while exerting minimal harmful effects on the environment. This eBook covers recent advances in biology, physiology of parasitism, genetics, population dynamics, resistance, host-parasite relationships, regulation of seed germination, etc., in order to offer an outstanding windows to these enigmatic plants, and contribute to their practical management