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Induction of defense mechanisms in greengram leaves and suspension-cultured cells by Macrophomina phaseolina and its elicitors / Induktion von Resistenzmechanismen in Blättern von Mungbohnen und in Suspensionszellkulturen durch Macrophomina phaseolina und seinen Elicitoren

A. Ramanathan, P. Vidhasekaran and R. Samiyappan
Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz / Journal of Plant Diseases and Protection
Vol. 107, No. 3 (Mai 2000), pp. 245-257
Published by: Verlag Eugen Ulmer KG
Stable URL: http://www.jstor.org/stable/43386991
Page Count: 13
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Induction of defense mechanisms in greengram leaves and suspension-cultured cells by Macrophomina phaseolina and its elicitors / Induktion von Resistenzmechanismen in Blättern von Mungbohnen und in Suspensionszellkulturen durch Macrophomina phaseolina und seinen Elicitoren
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Abstract

When greengram (Vigna radiata) leaves were inoculated with Macrophomina phaseolina y activities of phenylalanine ammonia-lyase (PAL) and peroxidase activities increased several fold. Synthesis of phenolics and lignin were also induced in the inoculated leaves. A glycoprotein elicitor was isolated from cell walls of M phaseolina. Another proteinaceous elicitor with xylanase activity was isolated from culture filtrate of the fungus. When the trifoliate leaves with petiols were dipped in either of these elicitors, similar increases in PAL and peroxidase and their metabolic products phenolics and lignin were observed. Suspension-cultured cells of greengram, which responded to the fungal elicitors, were established. When the suspension-cultured cells were treated with either of these elicitors, a sharp increase in PAL and peroxidase activities and several fold increases in the synthesis of phenolics and lignin were observed. Thus, cultured greengram cells mimic the reaction of the greengram leaves and the fungal elicitors mimic the true fungal infection process. Nach Inokulation von Blättern der Mungbohne (Vigna radiata) mit Macrophomina phaseolina nahmen die Aktivitäten der Phenylalaninammonium-Lyase (PAL) und Peroxidase um ein Mehrfaches zu. Auch die Synthese von phenolischen Substanzen und Lignin wurde in den inokulierten Blättern induziert. Aus den Zellwänden von M. phaseolina konnte ein Glykoprotein als Elicitor und ein anderer mit Proteincharakter und Xylanaseaktivität aus dem Kulturfìltrat isoliert werden. Eintauchen der Blätter mit den Stielen in Lösungen der jeweiligen Elicitoren führte zu ähnlichen Erhöhungen der PAL und Peroxidase sowie der phenolischen Substanzen und des Lignins. Ferner gelang es, Suspensionszellkulturen der Mungbohne anzulegen, die auf die pilzlichen Elicitoren reagierten. Behandlungen der Suspensionszellkulturen mit den jeweiligen Elicitoren hatten einen starken Anstieg der PAL- und Peroxidaseaktivitäten sowie eine mehrfache Erhöhung der Synthese von phenolischen Substanzen und Lignin zur Folge. Also zeigen kultivierte Mungbohnenzellen genau die gleiche Reaktion wie Mungbohnenblätter und die pilzlichen Elicitoren wirken genau wie im natürlichen Infektionsprozess.

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