Il processo infettivo di Fusarium Culmorum su plantule di frumento: degradazione delle componenti della parete cellulare, induzione di metaboliti di difesa e varaizione del ph tissutale
Author(s)
Aleandri, Maria Pia
Date Issued
January 31, 2006
Type
Doctoral Thesis
Abstract
Foot rot caused by Fusarium culmorum represents one of the most serious seed- and soil-borne diseases of wheat worldwide. During an ongoing research focused on the plant-microbe interaction wheat-F.culmorum, pectolytic enzymes produced by this pathogen in a liquid medium containing pectin as sole carbon source and in inoculated wheat seedlings were studied quantitatively and qualitatively. The pathogen was capable to produce in vitro both polygalacturonase (PG) and pectin-lyase (PNL). Total PNL was found to be active also on polygalacturonic acid and in the absence of Ca++; however, increasing doses of this cation consistently augmented the catalytic activity. Total PNL and PG activity was represented by an isoenzymatic complex. During early growing, F. culmorum produced in vitro only PG, whereas during further phases the pathogen produced mainly PNL accompanied by an increase of pH value of medium close to the PNL optimum activity. Moreover, PNL isoenzymes were differentially active at diverse pH values, thus indicating a high degree of flexibility of this enzyme complex. F. culmorum was capable to produce a pectolytic isoenzymatic pattern similar to that observed in vitro also during wheat seedlings colonisation and to enhance tissue pH level, even if less pronounced than that observed in vitro. Results suggest that alkalinisation process may represent a co-factor of F. culmorum pathogenicity.
Additional information
Dottorato di ricerca in Protezione delle piante
Subjects
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mpaleandri_tesid.pdf
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