Electronmicroscopic demonstration of peroxidase activities in Phaseolus vulgaris after infection with Uromyces phaseoli typica

Abstract

Eleetronmicroscopic Demonstration of Peroxidase Activitiesin Phaseolus vulgaris after Infection with Uromyces phaseoli typica Summary. Peroxidase activity in Phaseolus vulgaris (cultivar Favorit), infected with Uromyces phaseoli typica, was studied with the help of an electronmicroscope.The plant material was prefixed three days after inoculation and 3,3-diaminobenzidine was used as a substrate to detect the enzyme activity.The mitochondrial membranes showed an enhanced enzyme activity (due to a cytochrome oxidase or possibly due to a cytochrome peroxidase) in the infected ceil. There was no change in the structure and catalase activity of peroxisomes of the host. No catalase activity was detected in the fungus.A layer with evident peroxidase activity is seen outside the cell wall. This layer is sometimes thickened especially when it is in touch with intercellular hyphae.The penetration site of the haustorium has been intensively studied. Activity was observed in the neck region (from the penetration site of the haustorium to the neckband) in the zone between the host plasmalemma and the plasmalemma of the fungus. Some activity was also seen on the cisternae of the endoplasmic reticulum surrounding the neck. In a few preparations, activity was also found between sheath and wall of the haustorium.ZusammeuJassung. Bei der Wirt-Parasit-Kombination Phaseolus vulgaris (cv. Favorit) und Uromyces phaseoli typica wird die Aktivit/it peroxydatischer Enzyme am dritten Tag nach Infektion elektronenmikroskopisch dargestellt. Die Aktivit/it in den Mitochondrien (m6glicherweise eine Cytochromoxydase oder Cytochromperoxydase) ist in der infizierten Zelle erh5ht. Die Peroxisomen (sic enthalten eine Katalase) bleiben in der infizierten Zelle unver~ndert. Im Pilz wird keine Katalaseaktivit~t gefunden.Die Schicht mit peroxydatischer Aktivit~t auf der AuBenseite der Zellwand (Zellwandperoxydase) ist an der Beriihrungsstelle Hyphe --Wirtswand oft verdickt. An der Eintrittsstelle des Hanstoriums in die Zelle wird Aktivit~tt auf der Wand des Haustoriumhalses und auf den Cisternen des benachbarten ribosomenbesetzten endoplasmatischen getieulums beobaehtet. Manehmal finder man aueh eine Sehieht mit peroxydatischer Aktivit~t zwischen Scheide und Wand des ttaustoriums.Bei verschiedenen Wirt-Parasit-Kombinationen wird nach Infektion ein Anstieg der Peroxydaseaktivit/~t beobachtet (Wood, 1967;Kosuge, 1969). Nach Auftrennung in Isoenzyme zeigen jedoeh nieht

Ultrastructural demonstration of different peroxidase activities during the bean rust infection process

“…After heat treatment, the dark deposit of oxidized DAB was absent. This corresponds to our earlier results [20].…”

“…However, 3 days after infection, haustoria had neckbands [9,20] and the peroxidase activity on the haustorial neck reached up to the neckband [20].…”

“…These studies were made either by measuring the total peroxidase activity in extracts or by separating proteins by gel electrophoresis and staining of bands for enzyme activity. Mter incubation of bean rust infected leaves with 3,3'-diaminobenzidine, the ultrastructural localization of the oxidized substrate indicated peroxidase activities on the outside of the cell wall, on the haustorial neck at the site of fungal penetration and sometimes on the ribosomes of the endoplasmic reticulum around the haustorium [20].…”

“…These studies were made either by measuring the total peroxidase activity in extracts or by separating proteins by gel electrophoresis and staining of bands for enzyme activity. Mter incubation of bean rust infected leaves with 3,3'-diaminobenzidine, the ultrastructural localization of the oxidized substrate indicated peroxidase activities on the outside of the cell wall, on the haustorial neck at the site of fungal penetration and sometimes on the ribosomes of the endoplasmic reticulum around the haustorium [20].Recent electrophoretic studies [21] show that only a temporary increase of some peroxidase isoenzymes occurs during the first 24 h after infection.The purpose of this study was to investigate: (1) whether the increase of peroxidase activity is a contribution of the host or the pathogen; (2) if this enzyme influences the fungal penetration in the leaf as weil as the formation of the first haustorium within the leaf cells; and (3) whether synthesis of peroxidase occurs in particular cell organelles during infection.Physiological Plant Pathology (1975) 6,275-282 Ultrastructural demonstration of different peroxidase activities during the bean rust infection process KURT …”

Micro-autoradiographic studies on host-parasite interactions

“…Around the bean rust haustorium, these secretory vesicles contain peroxidase activity (Mendgen, 1975). In older haustoria, the peroxidase activity can be detected in the sheath (Mendgen and Fuchs, 1973). However, it remained open if only the host contributes to the sheath material or both, host and parasite.…”