Changes in chemical composition related to fungal infection and induced resistance in carnation and radish investigated by pyrolysis mass spectrometry

Abstract

Pseudomonas fluorescens WCR 417r induces systemic resistance in radish roots challenged by Fusarium oxysporum f. sp. raphani and, incidentally, in carnation stems challenged by Fusarium oxysporum f. sp. dianthi. The induced systemic resistance is not associated with accumulation of pathogenesis-related proteins (PRs) or, at least in case of radish, with increased peroxidase activity. We tested whether the induced systemic resistance might be associated with changes in the host cell wall composition. Cell wall degradation, using pyrolysis mass spectrometry, was demonstrated on fungal infection in carnation and probably in radish as well. Lignin was found to be demethoxylated, oxidized and depolymerized. In carnation both syringyl and guaiacyl lignin were broken down. In radish root probably mainly syringyl lignin was degraded. Cellulose and hemicellulose were degraded in carnation and possibly in radish. Bacterization with P. fluorescens WCS 417r prior to fungal infection reduced such cell wall degradation, consistent with its resistance inducing action. In the case of the radish roots it seems very improbable that this reduction is a necessary component of the induced fungal resistance. For carnation it remains to be investigated.

Shikimic Acid and Salicylic Acid Induced Protection on Growth Vigor, Seed Yield and Biochemical Aspects of Yielded Seeds of Vicia faba Plants Infected by Botrytis fabae

“…Meanwhile, the reduction in shoot dry weight might be related to increased rate of respiration and decompartementalization due to membrane degradation as suggested by Orcutt and Nilsen [24]. Furthermore, the present results showed that infection by B. fabae markedly decreased fresh and dry weights in roots of faba bean plants, and this may be related to the accumulation and action of phenolics produced from degradation of cell wall (lignin) mainly via depolymerization resulting from fungal elicitors [25].…”

Biological management of Fusarium wilt of tomato using biofortified vermicompost

“…This hormonal imbalance in tomato seedling after Fusarium infection included the accumulation of ABA and reduction of IAA, GA3 and cytokinines (El-Khallal2007). In addition, the short root and shoot lengths in tomato seedlings infected with Fusarium oxysporum could be due to the production of some toxins by fungi and the accumulation of phenolic compounds produced from the cell wall degradation mainly lignin via depolymerization resulting from fungal elicitors (Steijl et al 1999, Hanaa et al 2011 The evolution of wilt disease incidence in tomato plants infected with Fusarium oxysporum f. sp. lycopersici was recorded at different time interval.…”

Pseudomonas fluorescens, a potential bacterial antagonist to control plant diseases

“…Meena et al (1999) got a substantial increase in phenyl alanine ammonia lyase activity in rice leaves sprayed with P. fluorescens Pf 1 strain one day after treatment, whereas maximum activity was observed 3 days after treatment. Steijl et al (1999) working with radish and carnation for control of F. oxysporum f. sp. raphani and F. oxysporum f. sp.…”