Colletotrichin Causes Rapid Membrane Damage to Plant Cells

Abstract

The effect of colletotrichin, purified from Colletotricbum tabacum, on a diverse array of physiological processes was determined. Colletotrichin caused rapid loss of membrane integrity, as measured by cellular electrolyte leakage, in leaf discs of tobacco, cucumber, and four nightshade (Solanum) species floated on a 0.3 mM solution of the phy to toxin. The first ultrastructural damage observable was plasmolysis and disruption of the plasmalemma. Loss of membrane integrity occurred at similar rates in light or darkness and was dependent upon the presence of atmospheric oxygen. Membrane destruction was associated with an increase in malondialdehyde formation, an indicator of membrane lipid peroxidation. However, several free radical‐quenching compounds did not reduce the effect of colletotrichin on cellular leakage. No direct effect of colletotrichin was found on photosynthesis, respiration, ATPase activity, or membrane‐generated proton gradients. Calcium uptake and transport by plant roots were inhibited by the compound; however, the effect was relatively slow and was probably a secondary effect. Colletotrichin acted synergistically with atrazine, additively with paraquat, and antagonistically with acifluorfen. Acifluorfen activity requires oxidation of plastidsynthesized protoporphyrinogen to protoporphyrin IX at the plasmalemma. This process was inhibited by colletotrichin. These data indicate that colletotrichin causes oxidative plasmalemma destruction by an unknown mechanism. Zusammenfassung Colletotrichin verursacht eine rasche Beschädigung der Membran in Pflanzenzellen Ermittelt wurde der Einfluß von CoEetotrichin, gereinigt aus Colletotrichum tabacum, auf eine Reihe von physiologischen Prozessen. Blattscheiben von Tabak, Gurken und vier Nachtschattengewächsen (Solanum spp.), die auf einer 0,3 mM‐Lösung des Phytotoxins schwammen, zeigten eine rasche Beschädigung der Membran, festgestellt durch zellularen Elektrolytenverlust, als Folge der Colletotrichin‐Behandlung. Eine Plasmolyse und der Zerfall des Plasmalemmas wurde als erste ultrastrukturelle Beobachtung ermittelt. Ein Verlust der Membranintegrität ereignete sich mit einer ähnlichen Geschwindigkeit im Licht wie in Dunkelheit, und zwar in Abhängigkeit vom Vorhandensein von atmospharischem Sauerstoff. Die Membranzerstorung war mit einer Erhöhung der Malondialdehydproduktion verbunden, ein Zeichen der Membranlipidperoxidation. Einige, Freie Radikale löschende Substanzen konnten jedoch den CoUetotrichin‐Einfluß auf den zellularen Verlust nicht reduzieren. Ein direkter Einfluß des Colletotrichins auf die Photosynthese, die Atmung, die ATPase‐ Aktivitat oder auf membranerzeugte Protongradienten wurde nicht festgestellt. Die Kalziumaufnahme und dessen Transport durch Pflanzenwurzeln wurde durch die Verbindung gehemmt, dies erfolgte relativ langsam und konnte daher als sekundäre Wirkung der Substanz betrachtet werden. Colletotrichin wirkte synergistisch mit Atrazin, ergänzend mit Paraquat, und antagonistisch mit Acifluorfen. Acifluorfen‐Aktivität benö...

Responses of embryogenic mango cultures and seedling bioassays to a partially purified phytotoxin produced by a mango leaf isolate of Colletotrichum gloeosporioides penz

“…While some phytotoxins, e.g., helminthosporin, are host-specific (Wheeler, 1975), all of the Colletotrichum phytotoxins reported are nonspecific (Sahni et al, 1974;Gohbara et al, 1978;Duke et al, 1992). This is corroborated by the present study in which the partially purified phytotoxin was lethal to two non-hosts, lettuce and tobacco.…”

“…The development of necrotic spots following inoculation of mango leaves with partially purified phytotoxin is similar to the effect of colletotrichins on tobacco leaves (Duke et al, 1992). Inhibition of seed germination is also a useful bioassay for demonstrating phytotoxicity (Gohbara et al, 1978;Yoder, 1980) and was confirmed by the lettuce and tobacco seed bioassays in our study.…”

“…(Sahni et al, 1974), C. musae (Berk. and M. A. Curtis) (Chen, 1968) and C. nicotianae (Gohbara et al, 1978;Duke et al, 1992) have also been shown to produce phytotoxins that are involved in the disease process. Colletotrichum gloeosporioides produces phytotoxic metabolites in vitro and in vivo in Citrus aurantifolia L. (Sharma and Sharma, 1969;Sahni et al, 1974), northern jointvetch (Aeschynomene virginica L.) (Walker and Templeton, 1978), olive (Olea europaea L.) (Ballio et al, 1969;Bosquet et al, 1971) and Stylosanthes scabra L. (Szabados et al, 1987).…”

Microbial detoxification of pathotoxin produced by spot blotch pathogen Bipolaris sorokiniana infecting wheat

“…Malathi et al (2002) also reported reduction of electrolytes loss caused by toxin produced from Collectrotricum falcatum, a sugarcane pathogen by its treatment with antagonists, P. fluorescens and T. harzianum. It has been observed that reduction of symptom production and electrolyte leakage by antagonists are positively correlated, which has been reported in various other crops such as oats by victorin (Damann et al 1974); and tobacco, cucumber and Solanum species by collectotrichin (Duke et al 1992). Our results were in agreement with Sriram et al (2000), who observed a sharp fall in electrolyte leakage after treating the pathotoxin from R. solani with the biocontrol agents.…”

Actividad fitotóxica del filtrado crudo de colletotrichum gloeosporioides en cardamomo (elettaria cardamomum)

“…En el filtrado del cultivo de Colletotrichum, se han encontrado sustancias fitotóxicas que interfieren con los mecanismos subcelulares y se sugiere que poseen actividad mutagénica (Jayasankar et al, 1998). También, se encuentran diversas enzimas que pueden degradar paredes celulares, macerar tejidos y alterar la permeabilidad de las células de la planta causando pérdida de la integridad foliar (Duke et al, 1992;Levi et al, 2007;Theerthagiri et al, 2008). Los metabolitos producidos por esta especie son de diferente tipo, entre ellos se encuentran; diterpenos como colletotricina A, B y C (Gohbara et al, 1978); taxol (Gangadevi, 2008); lpoliaminoacidos como las aspergillomarasmina A y B (Ballio et al, 1969) y pironas, como las colletopironas (Gohbara et al, 1976).…”