Troise, Ciro (2014) Fungal phytotoxins as natural herbicides for weeds biocontrol in pastures and crops. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Lingua: English
Title: Fungal phytotoxins as natural herbicides for weeds biocontrol in pastures and crops
Creators:
CreatorsEmail
Troise, Cirociro.troise2@unina.it
Date: 31 March 2014
Number of Pages: 172
Institution: Università degli Studi di Napoli Federico II
Department: Agraria
Scuola di dottorato: Scienze agrarie e agro-alimentari
Dottorato: Agrobiologia e agrochimica
Ciclo di dottorato: 26
Coordinatore del Corso di dottorato:
nomeemail
Carputo, Domenicocarputo@unina.it
Tutor:
nomeemail
Evidente, AntonioUNSPECIFIED
Date: 31 March 2014
Number of Pages: 172
Uncontrolled Keywords: Phytotoxins, Natural herbicides
Settori scientifico-disciplinari del MIUR: Area 07 - Scienze agrarie e veterinarie > AGR/12 - Patologia vegetale
Area 07 - Scienze agrarie e veterinarie > AGR/13 - Chimica agraria
Area 03 - Scienze chimiche > CHIM/06 - Chimica organica
Date Deposited: 08 Apr 2014 09:08
Last Modified: 26 Jan 2015 11:50
URI: http://www.fedoa.unina.it/id/eprint/9927

Abstract

A phytotoxic substituted salycilic aldehyde, named agropyrenol, produced in liquid culture by Ascochyta agropyrina var. nana, a potential mycoherbicide proposed for the control of perennial weed Elytrigia repens, was characterized together with other two new minor metabolites named agropyrenale and agropyrenone, respectively. When assayed on different weedy plants, agropyrenol showed a strong phytotoxic activity, agropyrenale was less active, while agropyrenone was inactive. Six derivatives obtained by chemical modifications of agropyrenol were assayed for phytotoxic, antimicrobial and zootoxic activities, and the structure-activity relationships were examined. Both the double bond and the diol system of the 3,4-dihydroxypentenyl side chain, as well as the aldehyde group at C-6 and C-1 of the phenolic ring of agropyrenol proved to be important for the phytotoxicity. A new phytotoxic geranylcyclohexentriol, named phomentrioloxin, was isolated from the liquid culture of Phomopsis sp., a fungal pathogen proposed for the biological control of Carthamus lanatus, a widespread and troublesome thistle weed belonging to the Asteraceae family causing severe crop and pastures losses in Australia. Seven derivatives obtained by chemical modifications of the toxin were assayed for phytotoxic, antimicrobial and zootoxic activities, and the structure-activity relationships were examined. The hydroxy groups at C-2 and C-4 appeared to be important features for the phytotoxicity, as well as an unchanged cyclohexentriol ring. A role seemed also to be played by the unsaturations of the geranyl side chain. These findings could be useful for understanding the mechanisms of action of novel natural products, for identifying the active sites, and possibly in devising new herbicides of natural origin.

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