scholarly journals Secretion and endocytosis at the interface of plants and fungi

1995 ◽  
Vol 73 (S1) ◽  
pp. 640-648 ◽  
Author(s):  
K. Mendgen ◽  
U. Bachem ◽  
M. Stark-Urnau ◽  
H. Xu
Keyword(s):  
Plant Material ◽  
Plant Cell Wall ◽  
Signal Sequence ◽  
Rust Fungi ◽  
High Pressure Freezing ◽  
Vigna Sinensis ◽  
Immuno Electron Microscopy ◽  
Host Parasite ◽  
Further Development ◽  
Parasitic Phase

Secretion products and the uptake of material from the outside of the protoplasts of plants and microbes may influence the mutual interaction in host–parasite systems. Organelles involved in secretion by rust fungi have been characterized using immuno-electron microscopy. Proteins with the C-terminal histidine – aspartic acid – glutamic acid – leucine tetrapeptide (HDEL) signal sequence accumulated in tubular vesicular complexes of the ER in the parasitic phase of the fungi. The tubular complexes were differentiated from smooth cisternae that probably correspond to the Golgi equivalent. In the plant, material was secreted into the papilla and at the same time, endocytosis of 1, 3-β-glucans by clathrin-coated vesicles occurred at the penetration site of the monokaryotic appressorium. During further development of monokaryotic haustoria, different wall layers were produced around these haustoria. Components of those layers were plant cell wall constituents most of which were also detected in the Golgi apparatus. One layer was rich in callose, which is supposed to be synthesized at the plasma membrane. Obviously, endo- and exo-cytosis occur permanently by host and parasite during fungal development within the plant. Key words: Uromyces, Golgi, secretion, endocytosis, high-pressure freezing, Saccharomyces, Vigna sinensis, Vicia faba.

scholarly journals Capillaria hepatica-induced septal fibrosis in rats: a contribution to the study of liver fibrogenesis

2010 ◽  
Vol 43 (5) ◽  
pp. 504-507 ◽  
Author(s):  
Valter Lucas Chaves Barbosa ◽  
Zilton de Araújo Andrade
Keyword(s):  
Wistar Rats ◽  
Curative Treatment ◽  
Treatment Results ◽  
Treatment Methods ◽  
Capillaria Hepatica ◽  
End Of Treatment ◽  
Liver Fibrogenesis ◽  
Host Parasite ◽  
Further Development

INTRODUCTION: Septal fibrosis of the liver regularly develops in rats infected with the nematode Capillaria hepatica. Curative treatment of the infection prevents the development of septal fibrosis when intervention occurs up to postinfection day (PID) 15, but not later. The present investigation aimed to demonstrate which parasitic factors are present when the process of septal fibrosis can no longer be prevented by curative treatment. METHODS: Wistar rats were infected with 600 embryonated eggs of C. hepatica administered by gavage and treated with ivermectin and mebendazole in separate groups at PIDs 10, 12, 15, 17 or 20. Rats from each group and their nontreated controls, were killed and examined 40 days after the end of treatment. RESULTS: Findings by PID 15 were compatible with the stage of complete maturation of infection, when worms and eggs were fully developed and a complex host-parasite multifocal necroinflammatory reaction showed greater intensity, but with no signs of septal fibrosis, which appeared from PID 17 onward. CONCLUSIONS: Since the worms spontaneously died by PID 15, not only septal fibrosis production, but also its maintenance and further development appeared dependent on the presence of eggs, which were the only parasitic factor remaining thereafter.

scholarly journals A Meloidogyne graminicola Pectate Lyase Is Involved in Virulence and Activation of Host Defense Responses

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiansong Chen ◽  
Zhiwen Li ◽  
Borong Lin ◽  
Jinling Liao ◽  
Kan Zhuo
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Signal Sequence ◽  
Expression System ◽  
Pectate Lyase ◽  
Defense Responses ◽  
Hydrolytic Activity ◽  
Parasitic Nematodes ◽  
Cell Wall Degrading Enzymes

Plant-parasitic nematodes secrete an array of cell-wall-degrading enzymes to overcome the physical barrier formed by the plant cell wall. Here, we describe a novel pectate lyase gene Mg-PEL1 from M. graminicola. Quantitative real-time PCR assay showed that the highest transcriptional expression level of Mg-PEL1 occurred in pre-parasitic second-stage juveniles, and it was still detected during the early parasitic stage. Using in situ hybridization, we showed that Mg-PEL1 was expressed exclusively within the subventral esophageal gland cells of M. graminicola. The yeast signal sequence trap system revealed that it possessed an N-terminal signal peptide with secretion function. Recombinant Mg-PEL1 exhibited hydrolytic activity toward polygalacturonic acid. Rice plants expressing RNA interference vectors targeting Mg-PEL1 showed an increased resistance to M. graminicola. In addition, using an Agrobacterium-mediated transient expression system and plant immune response assays, we demonstrated that the cell wall localization of Mg-PEL1 was required for the activation of plant defense responses, including programmed plant cell death, reactive oxygen species (ROS) accumulation and expression of defense-related genes. Taken together, our results indicated that Mg-PEL1 could enhance the pathogenicity of M. graminicola and induce plant immune responses during nematode invasion into plants or migration in plants. This provides a new insight into the function of pectate lyases in plants-nematodes interaction.

Radiation, Biological Diversity and Host–Parasite Interactions in Wild Roses, Rust Fungi and Insects

2010 ◽  
pp. 215-238
Author(s):  
Annette Kohnen ◽  
Roland Brandl ◽  
Roman Fricke ◽  
Friederike Gallenmüller ◽  
Katrin Klinge ◽  
...  
Keyword(s):  
Biological Diversity ◽  
Rust Fungi ◽  
Host Parasite Interactions ◽  
Host Parasite

scholarly journals A Rhamnogalacturonan Lyase in the Clostridium cellulolyticum Cellulosome

2003 ◽  
Vol 185 (16) ◽  
pp. 4727-4733 ◽  
Author(s):  
Sandrine Pagès ◽  
Odile Valette ◽  
Laetitia Abdou ◽  
Anne Bélaïch ◽  
Jean-Pierre Bélaïch
Keyword(s):  
Plant Cell Wall ◽  
Biochemical Characterization ◽  
Catalytic Domain ◽  
Specific Activity ◽  
Signal Sequence ◽  
Present Report ◽  
Reading Frame ◽  
Clostridium Cellulolyticum ◽  
Rhamnogalacturonan I ◽  
Large Gene

ABSTRACT Clostridium cellulolyticum secretes large multienzymatic complexes with plant cell wall-degrading activities named cellulosomes. Most of the genes encoding cellulosomal components are located in a large gene cluster: cipC-cel48F-cel8C-cel9G-cel9E-orfX-cel9H-cel9J-man5K-cel9M. Downstream of the cel9M gene, a new open reading frame was discovered and named rgl11Y. Amino acid sequence analysis indicates that this gene encodes a multidomain pectinase, Rgl11Y, containing an N-terminal signal sequence, a catalytic domain belonging to family 11 of the polysaccharide lyases, and a C-terminal dockerin domain. The present report describes the biochemical characterization of a recombinant form of Rgl11Y. Rgl11Y cleaves the α-l-Rhap-(1→4)-α-d-GalpA glycosidic bond in the backbone of rhamnogalacturonan I (RGI) via a β-elimination mechanism. Its specific activity on potato pectic galactan and rhamnogalacturonan was found to be 28 and 3.6 IU/mg, respectively, indicating that Rgl11Y requires galactan decoration of the RGI backbone. The optimal pH of Rgl11Y is 8.5 and calcium is required for its activity. Rgl11Y was shown to be incorporated in the C. cellulolyticum cellulosome through a typical cohesin-dockerin interaction. Rgl11Y from C. cellulolyticum is the first cellulosomal rhamnogalacturonase characterized.

scholarly journals Early defence responses of cowpea (Vigna sinensis L.) induced by non-pathogenic rust fungi

Planta ◽  
1991 ◽  
Vol 185 (2) ◽  
Author(s):  
W. Fink ◽  
M. Haug ◽  
H. Deising ◽  
K. Mendgen
Keyword(s):  
Rust Fungi ◽  
Vigna Sinensis ◽  
Defence Responses
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