title: Gulypyrones A and B and Phomentrioloxins B and C Produced by Diaporthe gulyae, a Potential Mycoherbicide for Saffron Thistle (Carthamus lanatus).
abstract: 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.
authors.affiliation: †Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Andolfi
authors.affiliation: ‡Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Via Amendola 122/O, 70125, Bari, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Boari
authors.affiliation: †Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Evidente
authors.affiliation: †Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Cimmino
authors.affiliation: ‡Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Via Amendola 122/O, 70125, Bari, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Vurro
authors.affiliation: §Graham Centre for Agriculture Innovation (an alliance between Charles Sturt University and NSW DPI), Booroma Street, Locked Bag 588, Wagga Wagga, NSW 2678, Australia.
authors.forename: Gavin
authors.initials: G
authors.lastname: Ash
authors.affiliation: †Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126, Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Evidente
mesh_terms: D001203:Ascomycota / Q000737:chemistry*; D001315:Australia; D001547:Benzaldehydes / Q000302:isolation & purification; D031178:Carthamus / Q000382:microbiology*; D003511:Cyclohexanols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006540:Herbicides / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D015394:Molecular Structure; D009574:Nitro Compounds / Q000302:isolation & purification; D011422:Propionates / Q000302:isolation & purification; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D001547:Benzaldehydes; D003511:Cyclohexanols; D006540:Herbicides; D009574:Nitro Compounds; D011422:Propionates; D011753:Pyrones; C000600344:gulypyrone A; C000600346:gulypyrone B; C574853:phomentrioloxin; C000600347:phomentrioloxin B; C000600348:phomentrioloxin C; C011483:4-hydroxybenzaldehyde; C015392:3-nitropropionic acid